drivers/scsi/st.c

   1 /*
   2    SCSI Tape Driver for Linux version 1.1 and newer. See the accompanying
   3    file Documentation/scsi/st.txt for more information.
   4
   5    History:
   6    Rewritten from Dwayne Forsyth's SCSI tape driver by Kai Makisara.
   7    Contribution and ideas from several people including (in alphabetical
   8    order) Klaus Ehrenfried, Eugene Exarevsky, Eric Lee Green, Wolfgang Denk,
   9    Steve Hirsch, Andreas Koppenh"ofer, Michael Leodolter, Eyal Lebedinsky,
  10    Michael Schaefer, J"org Weule, and Eric Youngdale.
  11
  12    Copyright 1992 - 2016 Kai Makisara
  13    email Kai.Makisara@kolumbus.fi
  14
  15    Some small formal changes - aeb, 950809
  16
  17    Last modified: 18-JAN-1998 Richard Gooch <rgooch@atnf.csiro.au> Devfs support
  18  */
  19
  20 static const char *verstr = "20160209";
  21
  22 #include <linux/module.h>
  23
  24 #include <linux/fs.h>
  25 #include <linux/kernel.h>
  26 #include <linux/sched/signal.h>
  27 #include <linux/mm.h>
  28 #include <linux/init.h>
  29 #include <linux/string.h>
  30 #include <linux/slab.h>
  31 #include <linux/errno.h>
  32 #include <linux/mtio.h>
  33 #include <linux/cdrom.h>
  34 #include <linux/ioctl.h>
  35 #include <linux/fcntl.h>
  36 #include <linux/spinlock.h>
  37 #include <linux/blkdev.h>
  38 #include <linux/moduleparam.h>
  39 #include <linux/cdev.h>
  40 #include <linux/idr.h>
  41 #include <linux/delay.h>
  42 #include <linux/mutex.h>
  43
  44 #include <linux/uaccess.h>
  45 #include <asm/dma.h>
  46
  47 #include <scsi/scsi.h>
  48 #include <scsi/scsi_dbg.h>
  49 #include <scsi/scsi_device.h>
  50 #include <scsi/scsi_driver.h>
  51 #include <scsi/scsi_eh.h>
  52 #include <scsi/scsi_host.h>
  53 #include <scsi/scsi_ioctl.h>
  54 #include <scsi/sg.h>
  55
  56
  57 /* The driver prints some debugging information on the console if DEBUG
  58    is defined and non-zero. */
  59 #define DEBUG 1
  60 #define NO_DEBUG 0
  61
  62 #define ST_DEB_MSG  KERN_NOTICE
  63 #if DEBUG
  64 /* The message level for the debug messages is currently set to KERN_NOTICE
  65    so that people can easily see the messages. Later when the debugging messages
  66    in the drivers are more widely classified, this may be changed to KERN_DEBUG. */
  67 #define DEB(a) a
  68 #define DEBC(a) if (debugging) { a ; }
  69 #else
  70 #define DEB(a)
  71 #define DEBC(a)
  72 #endif
  73
  74 #define ST_KILOBYTE 1024
  75
  76 #include "st_options.h"
  77 #include "st.h"
  78
  79 static int buffer_kbs;
  80 static int max_sg_segs;
  81 static int try_direct_io = TRY_DIRECT_IO;
  82 static int try_rdio = 1;
  83 static int try_wdio = 1;
  84 static int debug_flag;
  85
  86 static struct class st_sysfs_class;
  87 static const struct attribute_group *st_dev_groups[];
  88 static const struct attribute_group *st_drv_groups[];
  89
  90 MODULE_AUTHOR("Kai Makisara");
  91 MODULE_DESCRIPTION("SCSI tape (st) driver");
  92 MODULE_LICENSE("GPL");
  93 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_TAPE_MAJOR);
  94 MODULE_ALIAS_SCSI_DEVICE(TYPE_TAPE);
  95
  96 /* Set 'perm' (4th argument) to 0 to disable module_param's definition
  97  * of sysfs parameters (which module_param doesn't yet support).
  98  * Sysfs parameters defined explicitly later.
  99  */
 100 module_param_named(buffer_kbs, buffer_kbs, int, 0);
 101 MODULE_PARM_DESC(buffer_kbs, "Default driver buffer size for fixed block mode (KB; 32)");
 102 module_param_named(max_sg_segs, max_sg_segs, int, 0);
 103 MODULE_PARM_DESC(max_sg_segs, "Maximum number of scatter/gather segments to use (256)");
 104 module_param_named(try_direct_io, try_direct_io, int, 0);
 105 MODULE_PARM_DESC(try_direct_io, "Try direct I/O between user buffer and tape drive (1)");
 106 module_param_named(debug_flag, debug_flag, int, 0);
 107 MODULE_PARM_DESC(debug_flag, "Enable DEBUG, same as setting debugging=1");
 108
 109
 110 /* Extra parameters for testing */
 111 module_param_named(try_rdio, try_rdio, int, 0);
 112 MODULE_PARM_DESC(try_rdio, "Try direct read i/o when possible");
 113 module_param_named(try_wdio, try_wdio, int, 0);
 114 MODULE_PARM_DESC(try_wdio, "Try direct write i/o when possible");
 115
 116 #ifndef MODULE
 117 static int write_threshold_kbs;  /* retained for compatibility */
 118 static struct st_dev_parm {
 119         char *name;
 120         int *val;
 121 } parms[] __initdata = {
 122         {
 123                 "buffer_kbs", &buffer_kbs
 124         },
 125         {       /* Retained for compatibility with 2.4 */
 126                 "write_threshold_kbs", &write_threshold_kbs
 127         },
 128         {
 129                 "max_sg_segs", NULL
 130         },
 131         {
 132                 "try_direct_io", &try_direct_io
 133         },
 134         {
 135                 "debug_flag", &debug_flag
 136         }
 137 };
 138 #endif
 139
 140 /* Restrict the number of modes so that names for all are assigned */
 141 #if ST_NBR_MODES > 16
 142 #error "Maximum number of modes is 16"
 143 #endif
 144 /* Bit reversed order to get same names for same minors with all
 145    mode counts */
 146 static const char *st_formats[] = {
 147         "",  "r", "k", "s", "l", "t", "o", "u",
 148         "m", "v", "p", "x", "a", "y", "q", "z"};
 149
 150 /* The default definitions have been moved to st_options.h */
 151
 152 #define ST_FIXED_BUFFER_SIZE (ST_FIXED_BUFFER_BLOCKS * ST_KILOBYTE)
 153
 154 /* The buffer size should fit into the 24 bits for length in the
 155    6-byte SCSI read and write commands. */
 156 #if ST_FIXED_BUFFER_SIZE >= (2 << 24 - 1)
 157 #error "Buffer size should not exceed (2 << 24 - 1) bytes!"
 158 #endif
 159
 160 static int debugging = DEBUG;
 161
 162 #define MAX_RETRIES 0
 163 #define MAX_WRITE_RETRIES 0
 164 #define MAX_READY_RETRIES 0
 165 #define NO_TAPE  NOT_READY
 166
 167 #define ST_TIMEOUT (900 * HZ)
 168 #define ST_LONG_TIMEOUT (14000 * HZ)
 169
 170 /* Remove mode bits and auto-rewind bit (7) */
 171 #define TAPE_NR(x) ( ((iminor(x) & ~255) >> (ST_NBR_MODE_BITS + 1)) | \
 172     (iminor(x) & ~(-1 << ST_MODE_SHIFT)) )
 173 #define TAPE_MODE(x) ((iminor(x) & ST_MODE_MASK) >> ST_MODE_SHIFT)
 174
 175 /* Construct the minor number from the device (d), mode (m), and non-rewind (n) data */
 176 #define TAPE_MINOR(d, m, n) (((d & ~(255 >> (ST_NBR_MODE_BITS + 1))) << (ST_NBR_MODE_BITS + 1)) | \
 177   (d & (255 >> (ST_NBR_MODE_BITS + 1))) | (m << ST_MODE_SHIFT) | ((n != 0) << 7) )
 178
 179 /* Internal ioctl to set both density (uppermost 8 bits) and blocksize (lower
 180    24 bits) */
 181 #define SET_DENS_AND_BLK 0x10001
 182
 183 static int st_fixed_buffer_size = ST_FIXED_BUFFER_SIZE;
 184 static int st_max_sg_segs = ST_MAX_SG;
 185
 186 static int modes_defined;
 187
 188 static int enlarge_buffer(struct st_buffer *, int, int);
 189 static void clear_buffer(struct st_buffer *);
 190 static void normalize_buffer(struct st_buffer *);
 191 static int append_to_buffer(const char __user *, struct st_buffer *, int);
 192 static int from_buffer(struct st_buffer *, char __user *, int);
 193 static void move_buffer_data(struct st_buffer *, int);
 194
 195 static int sgl_map_user_pages(struct st_buffer *, const unsigned int,
 196                               unsigned long, size_t, int);
 197 static int sgl_unmap_user_pages(struct st_buffer *, const unsigned int, int);
 198
 199 static int st_probe(struct device *);
 200 static int st_remove(struct device *);
 201
 202 static struct scsi_driver st_template = {
 203         .gendrv = {
 204                 .name           = "st",
 205                 .owner          = THIS_MODULE,
 206                 .probe          = st_probe,
 207                 .remove         = st_remove,
 208                 .groups         = st_drv_groups,
 209         },
 210 };
 211
 212 static int st_compression(struct scsi_tape *, int);
 213
 214 static int find_partition(struct scsi_tape *);
 215 static int switch_partition(struct scsi_tape *);
 216
 217 static int st_int_ioctl(struct scsi_tape *, unsigned int, unsigned long);
 218
 219 static void scsi_tape_release(struct kref *);
 220
 221 #define to_scsi_tape(obj) container_of(obj, struct scsi_tape, kref)
 222
 223 static DEFINE_MUTEX(st_ref_mutex);
 224 static DEFINE_SPINLOCK(st_index_lock);
 225 static DEFINE_SPINLOCK(st_use_lock);
 226 static DEFINE_IDR(st_index_idr);
 227
 228
 229 \f
 230 #include "osst_detect.h"
 231 #ifndef SIGS_FROM_OSST
 232 #define SIGS_FROM_OSST \
 233         {"OnStream", "SC-", "", "osst"}, \
 234         {"OnStream", "DI-", "", "osst"}, \
 235         {"OnStream", "DP-", "", "osst"}, \
 236         {"OnStream", "USB", "", "osst"}, \
 237         {"OnStream", "FW-", "", "osst"}
 238 #endif
 239
 240 static struct scsi_tape *scsi_tape_get(int dev)
 241 {
 242         struct scsi_tape *STp = NULL;
 243
 244         mutex_lock(&st_ref_mutex);
 245         spin_lock(&st_index_lock);
 246
 247         STp = idr_find(&st_index_idr, dev);
 248         if (!STp) goto out;
 249
 250         kref_get(&STp->kref);
 251
 252         if (!STp->device)
 253                 goto out_put;
 254
 255         if (scsi_device_get(STp->device))
 256                 goto out_put;
 257
 258         goto out;
 259
 260 out_put:
 261         kref_put(&STp->kref, scsi_tape_release);
 262         STp = NULL;
 263 out:
 264         spin_unlock(&st_index_lock);
 265         mutex_unlock(&st_ref_mutex);
 266         return STp;
 267 }
 268
 269 static void scsi_tape_put(struct scsi_tape *STp)
 270 {
 271         struct scsi_device *sdev = STp->device;
 272
 273         mutex_lock(&st_ref_mutex);
 274         kref_put(&STp->kref, scsi_tape_release);
 275         scsi_device_put(sdev);
 276         mutex_unlock(&st_ref_mutex);
 277 }
 278
 279 struct st_reject_data {
 280         char *vendor;
 281         char *model;
 282         char *rev;
 283         char *driver_hint; /* Name of the correct driver, NULL if unknown */
 284 };
 285
 286 static struct st_reject_data reject_list[] = {
 287         /* {"XXX", "Yy-", "", NULL},  example */
 288         SIGS_FROM_OSST,
 289         {NULL, }};
 290
 291 /* If the device signature is on the list of incompatible drives, the
 292    function returns a pointer to the name of the correct driver (if known) */
 293 static char * st_incompatible(struct scsi_device* SDp)
 294 {
 295         struct st_reject_data *rp;
 296
 297         for (rp=&(reject_list[0]); rp->vendor != NULL; rp++)
 298                 if (!strncmp(rp->vendor, SDp->vendor, strlen(rp->vendor)) &&
 299                     !strncmp(rp->model, SDp->model, strlen(rp->model)) &&
 300                     !strncmp(rp->rev, SDp->rev, strlen(rp->rev))) {
 301                         if (rp->driver_hint)
 302                                 return rp->driver_hint;
 303                         else
 304                                 return "unknown";
 305                 }
 306         return NULL;
 307 }
 308 \f
 309
 310 static inline char *tape_name(struct scsi_tape *tape)
 311 {
 312         return tape->disk->disk_name;
 313 }
 314
 315 #define st_printk(prefix, t, fmt, a...) \
 316         sdev_prefix_printk(prefix, (t)->device, tape_name(t), fmt, ##a)
 317 #ifdef DEBUG
 318 #define DEBC_printk(t, fmt, a...) \
 319         if (debugging) { st_printk(ST_DEB_MSG, t, fmt, ##a ); }
 320 #else
 321 #define DEBC_printk(t, fmt, a...)
 322 #endif
 323
 324 static void st_analyze_sense(struct st_request *SRpnt, struct st_cmdstatus *s)
 325 {
 326         const u8 *ucp;
 327         const u8 *sense = SRpnt->sense;
 328
 329         s->have_sense = scsi_normalize_sense(SRpnt->sense,
 330                                 SCSI_SENSE_BUFFERSIZE, &s->sense_hdr);
 331         s->flags = 0;
 332
 333         if (s->have_sense) {
 334                 s->deferred = 0;
 335                 s->remainder_valid =
 336                         scsi_get_sense_info_fld(sense, SCSI_SENSE_BUFFERSIZE, &s->uremainder64);
 337                 switch (sense[0] & 0x7f) {
 338                 case 0x71:
 339                         s->deferred = 1;
 340                 case 0x70:
 341                         s->fixed_format = 1;
 342                         s->flags = sense[2] & 0xe0;
 343                         break;
 344                 case 0x73:
 345                         s->deferred = 1;
 346                 case 0x72:
 347                         s->fixed_format = 0;
 348                         ucp = scsi_sense_desc_find(sense, SCSI_SENSE_BUFFERSIZE, 4);
 349                         s->flags = ucp ? (ucp[3] & 0xe0) : 0;
 350                         break;
 351                 }
 352         }
 353 }
 354
 355
 356 /* Convert the result to success code */
 357 static int st_chk_result(struct scsi_tape *STp, struct st_request * SRpnt)
 358 {
 359         int result = SRpnt->result;
 360         u8 scode;
 361         DEB(const char *stp;)
 362         char *name = tape_name(STp);
 363         struct st_cmdstatus *cmdstatp;
 364
 365         if (!result)
 366                 return 0;
 367
 368         cmdstatp = &STp->buffer->cmdstat;
 369         st_analyze_sense(SRpnt, cmdstatp);
 370
 371         if (cmdstatp->have_sense)
 372                 scode = STp->buffer->cmdstat.sense_hdr.sense_key;
 373         else
 374                 scode = 0;
 375
 376         DEB(
 377         if (debugging) {
 378                 st_printk(ST_DEB_MSG, STp,
 379                             "Error: %x, cmd: %x %x %x %x %x %x\n", result,
 380                             SRpnt->cmd[0], SRpnt->cmd[1], SRpnt->cmd[2],
 381                             SRpnt->cmd[3], SRpnt->cmd[4], SRpnt->cmd[5]);
 382                 if (cmdstatp->have_sense)
 383                         __scsi_print_sense(STp->device, name,
 384                                            SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
 385         } ) /* end DEB */
 386         if (!debugging) { /* Abnormal conditions for tape */
 387                 if (!cmdstatp->have_sense)
 388                         st_printk(KERN_WARNING, STp,
 389                                "Error %x (driver bt 0x%x, host bt 0x%x).\n",
 390                                result, driver_byte(result), host_byte(result));
 391                 else if (cmdstatp->have_sense &&
 392                          scode != NO_SENSE &&
 393                          scode != RECOVERED_ERROR &&
 394                          /* scode != UNIT_ATTENTION && */
 395                          scode != BLANK_CHECK &&
 396                          scode != VOLUME_OVERFLOW &&
 397                          SRpnt->cmd[0] != MODE_SENSE &&
 398                          SRpnt->cmd[0] != TEST_UNIT_READY) {
 399
 400                         __scsi_print_sense(STp->device, name,
 401                                            SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
 402                 }
 403         }
 404
 405         if (cmdstatp->fixed_format &&
 406             STp->cln_mode >= EXTENDED_SENSE_START) {  /* Only fixed format sense */
 407                 if (STp->cln_sense_value)
 408                         STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
 409                                                STp->cln_sense_mask) == STp->cln_sense_value);
 410                 else
 411                         STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
 412                                                STp->cln_sense_mask) != 0);
 413         }
 414         if (cmdstatp->have_sense &&
 415             cmdstatp->sense_hdr.asc == 0 && cmdstatp->sense_hdr.ascq == 0x17)
 416                 STp->cleaning_req = 1; /* ASC and ASCQ => cleaning requested */
 417
 418         STp->pos_unknown |= STp->device->was_reset;
 419
 420         if (cmdstatp->have_sense &&
 421             scode == RECOVERED_ERROR
 422 #if ST_RECOVERED_WRITE_FATAL
 423             && SRpnt->cmd[0] != WRITE_6
 424             && SRpnt->cmd[0] != WRITE_FILEMARKS
 425 #endif
 426             ) {
 427                 STp->recover_count++;
 428                 STp->recover_reg++;
 429
 430                 DEB(
 431                 if (debugging) {
 432                         if (SRpnt->cmd[0] == READ_6)
 433                                 stp = "read";
 434                         else if (SRpnt->cmd[0] == WRITE_6)
 435                                 stp = "write";
 436                         else
 437                                 stp = "ioctl";
 438                         st_printk(ST_DEB_MSG, STp,
 439                                   "Recovered %s error (%d).\n",
 440                                   stp, STp->recover_count);
 441                 } ) /* end DEB */
 442
 443                 if (cmdstatp->flags == 0)
 444                         return 0;
 445         }
 446         return (-EIO);
 447 }
 448
 449 static struct st_request *st_allocate_request(struct scsi_tape *stp)
 450 {
 451         struct st_request *streq;
 452
 453         streq = kzalloc(sizeof(*streq), GFP_KERNEL);
 454         if (streq)
 455                 streq->stp = stp;
 456         else {
 457                 st_printk(KERN_ERR, stp,
 458                           "Can't get SCSI request.\n");
 459                 if (signal_pending(current))
 460                         stp->buffer->syscall_result = -EINTR;
 461                 else
 462                         stp->buffer->syscall_result = -EBUSY;
 463         }
 464
 465         return streq;
 466 }
 467
 468 static void st_release_request(struct st_request *streq)
 469 {
 470         kfree(streq);
 471 }
 472
 473 static void st_do_stats(struct scsi_tape *STp, struct request *req)
 474 {
 475         ktime_t now;
 476
 477         now = ktime_get();
 478         if (scsi_req(req)->cmd[0] == WRITE_6) {
 479                 now = ktime_sub(now, STp->stats->write_time);
 480                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_write_time);
 481                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 482                 atomic64_inc(&STp->stats->write_cnt);
 483                 if (scsi_req(req)->result) {
 484                         atomic64_add(atomic_read(&STp->stats->last_write_size)
 485                                 - STp->buffer->cmdstat.residual,
 486                                 &STp->stats->write_byte_cnt);
 487                         if (STp->buffer->cmdstat.residual > 0)
 488                                 atomic64_inc(&STp->stats->resid_cnt);
 489                 } else
 490                         atomic64_add(atomic_read(&STp->stats->last_write_size),
 491                                 &STp->stats->write_byte_cnt);
 492         } else if (scsi_req(req)->cmd[0] == READ_6) {
 493                 now = ktime_sub(now, STp->stats->read_time);
 494                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_read_time);
 495                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 496                 atomic64_inc(&STp->stats->read_cnt);
 497                 if (scsi_req(req)->result) {
 498                         atomic64_add(atomic_read(&STp->stats->last_read_size)
 499                                 - STp->buffer->cmdstat.residual,
 500                                 &STp->stats->read_byte_cnt);
 501                         if (STp->buffer->cmdstat.residual > 0)
 502                                 atomic64_inc(&STp->stats->resid_cnt);
 503                 } else
 504                         atomic64_add(atomic_read(&STp->stats->last_read_size),
 505                                 &STp->stats->read_byte_cnt);
 506         } else {
 507                 now = ktime_sub(now, STp->stats->other_time);
 508                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 509                 atomic64_inc(&STp->stats->other_cnt);
 510         }
 511         atomic64_dec(&STp->stats->in_flight);
 512 }
 513
 514 static void st_scsi_execute_end(struct request *req, blk_status_t status)
 515 {
 516         struct st_request *SRpnt = req->end_io_data;
 517         struct scsi_request *rq = scsi_req(req);
 518         struct scsi_tape *STp = SRpnt->stp;
 519         struct bio *tmp;
 520
 521         STp->buffer->cmdstat.midlevel_result = SRpnt->result = rq->result;
 522         STp->buffer->cmdstat.residual = rq->resid_len;
 523
 524         st_do_stats(STp, req);
 525
 526         tmp = SRpnt->bio;
 527         if (rq->sense_len)
 528                 memcpy(SRpnt->sense, rq->sense, SCSI_SENSE_BUFFERSIZE);
 529         if (SRpnt->waiting)
 530                 complete(SRpnt->waiting);
 531
 532         blk_rq_unmap_user(tmp);
 533         __blk_put_request(req->q, req);
 534 }
 535
 536 static int st_scsi_execute(struct st_request *SRpnt, const unsigned char *cmd,
 537                            int data_direction, void *buffer, unsigned bufflen,
 538                            int timeout, int retries)
 539 {
 540         struct request *req;
 541         struct scsi_request *rq;
 542         struct rq_map_data *mdata = &SRpnt->stp->buffer->map_data;
 543         int err = 0;
 544         struct scsi_tape *STp = SRpnt->stp;
 545
 546         req = blk_get_request(SRpnt->stp->device->request_queue,
 547                         data_direction == DMA_TO_DEVICE ?
 548                         REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, 0);
 549         if (IS_ERR(req))
 550                 return DRIVER_ERROR << 24;
 551         rq = scsi_req(req);
 552         req->rq_flags |= RQF_QUIET;
 553
 554         mdata->null_mapped = 1;
 555
 556         if (bufflen) {
 557                 err = blk_rq_map_user(req->q, req, mdata, NULL, bufflen,
 558                                       GFP_KERNEL);
 559                 if (err) {
 560                         blk_put_request(req);
 561                         return DRIVER_ERROR << 24;
 562                 }
 563         }
 564
 565         atomic64_inc(&STp->stats->in_flight);
 566         if (cmd[0] == WRITE_6) {
 567                 atomic_set(&STp->stats->last_write_size, bufflen);
 568                 STp->stats->write_time = ktime_get();
 569         } else if (cmd[0] == READ_6) {
 570                 atomic_set(&STp->stats->last_read_size, bufflen);
 571                 STp->stats->read_time = ktime_get();
 572         } else {
 573                 STp->stats->other_time = ktime_get();
 574         }
 575
 576         SRpnt->bio = req->bio;
 577         rq->cmd_len = COMMAND_SIZE(cmd[0]);
 578         memset(rq->cmd, 0, BLK_MAX_CDB);
 579         memcpy(rq->cmd, cmd, rq->cmd_len);
 580         req->timeout = timeout;
 581         rq->retries = retries;
 582         req->end_io_data = SRpnt;
 583
 584         blk_execute_rq_nowait(req->q, NULL, req, 1, st_scsi_execute_end);
 585         return 0;
 586 }
 587
 588 /* Do the scsi command. Waits until command performed if do_wait is true.
 589    Otherwise write_behind_check() is used to check that the command
 590    has finished. */
 591 static struct st_request *
 592 st_do_scsi(struct st_request * SRpnt, struct scsi_tape * STp, unsigned char *cmd,
 593            int bytes, int direction, int timeout, int retries, int do_wait)
 594 {
 595         struct completion *waiting;
 596         struct rq_map_data *mdata = &STp->buffer->map_data;
 597         int ret;
 598
 599         /* if async, make sure there's no command outstanding */
 600         if (!do_wait && ((STp->buffer)->last_SRpnt)) {
 601                 st_printk(KERN_ERR, STp,
 602                           "Async command already active.\n");
 603                 if (signal_pending(current))
 604                         (STp->buffer)->syscall_result = (-EINTR);
 605                 else
 606                         (STp->buffer)->syscall_result = (-EBUSY);
 607                 return NULL;
 608         }
 609
 610         if (!SRpnt) {
 611                 SRpnt = st_allocate_request(STp);
 612                 if (!SRpnt)
 613                         return NULL;
 614         }
 615
 616         /* If async IO, set last_SRpnt. This ptr tells write_behind_check
 617            which IO is outstanding. It's nulled out when the IO completes. */
 618         if (!do_wait)
 619                 (STp->buffer)->last_SRpnt = SRpnt;
 620
 621         waiting = &STp->wait;
 622         init_completion(waiting);
 623         SRpnt->waiting = waiting;
 624
 625         if (STp->buffer->do_dio) {
 626                 mdata->page_order = 0;
 627                 mdata->nr_entries = STp->buffer->sg_segs;
 628                 mdata->pages = STp->buffer->mapped_pages;
 629         } else {
 630                 mdata->page_order = STp->buffer->reserved_page_order;
 631                 mdata->nr_entries =
 632                         DIV_ROUND_UP(bytes, PAGE_SIZE << mdata->page_order);
 633                 mdata->pages = STp->buffer->reserved_pages;
 634                 mdata->offset = 0;
 635         }
 636
 637         memcpy(SRpnt->cmd, cmd, sizeof(SRpnt->cmd));
 638         STp->buffer->cmdstat.have_sense = 0;
 639         STp->buffer->syscall_result = 0;
 640
 641         ret = st_scsi_execute(SRpnt, cmd, direction, NULL, bytes, timeout,
 642                               retries);
 643         if (ret) {
 644                 /* could not allocate the buffer or request was too large */
 645                 (STp->buffer)->syscall_result = (-EBUSY);
 646                 (STp->buffer)->last_SRpnt = NULL;
 647         } else if (do_wait) {
 648                 wait_for_completion(waiting);
 649                 SRpnt->waiting = NULL;
 650                 (STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
 651         }
 652
 653         return SRpnt;
 654 }
 655
 656
 657 /* Handle the write-behind checking (waits for completion). Returns -ENOSPC if
 658    write has been correct but EOM early warning reached, -EIO if write ended in
 659    error or zero if write successful. Asynchronous writes are used only in
 660    variable block mode. */
 661 static int write_behind_check(struct scsi_tape * STp)
 662 {
 663         int retval = 0;
 664         struct st_buffer *STbuffer;
 665         struct st_partstat *STps;
 666         struct st_cmdstatus *cmdstatp;
 667         struct st_request *SRpnt;
 668
 669         STbuffer = STp->buffer;
 670         if (!STbuffer->writing)
 671                 return 0;
 672
 673         DEB(
 674         if (STp->write_pending)
 675                 STp->nbr_waits++;
 676         else
 677                 STp->nbr_finished++;
 678         ) /* end DEB */
 679
 680         wait_for_completion(&(STp->wait));
 681         SRpnt = STbuffer->last_SRpnt;
 682         STbuffer->last_SRpnt = NULL;
 683         SRpnt->waiting = NULL;
 684
 685         (STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
 686         st_release_request(SRpnt);
 687
 688         STbuffer->buffer_bytes -= STbuffer->writing;
 689         STps = &(STp->ps[STp->partition]);
 690         if (STps->drv_block >= 0) {
 691                 if (STp->block_size == 0)
 692                         STps->drv_block++;
 693                 else
 694                         STps->drv_block += STbuffer->writing / STp->block_size;
 695         }
 696
 697         cmdstatp = &STbuffer->cmdstat;
 698         if (STbuffer->syscall_result) {
 699                 retval = -EIO;
 700                 if (cmdstatp->have_sense && !cmdstatp->deferred &&
 701                     (cmdstatp->flags & SENSE_EOM) &&
 702                     (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
 703                      cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR)) {
 704                         /* EOM at write-behind, has all data been written? */
 705                         if (!cmdstatp->remainder_valid ||
 706                             cmdstatp->uremainder64 == 0)
 707                                 retval = -ENOSPC;
 708                 }
 709                 if (retval == -EIO)
 710                         STps->drv_block = -1;
 711         }
 712         STbuffer->writing = 0;
 713
 714         DEB(if (debugging && retval)
 715                     st_printk(ST_DEB_MSG, STp,
 716                                 "Async write error %x, return value %d.\n",
 717                                 STbuffer->cmdstat.midlevel_result, retval);) /* end DEB */
 718
 719         return retval;
 720 }
 721
 722
 723 /* Step over EOF if it has been inadvertently crossed (ioctl not used because
 724    it messes up the block number). */
 725 static int cross_eof(struct scsi_tape * STp, int forward)
 726 {
 727         struct st_request *SRpnt;
 728         unsigned char cmd[MAX_COMMAND_SIZE];
 729
 730         cmd[0] = SPACE;
 731         cmd[1] = 0x01;          /* Space FileMarks */
 732         if (forward) {
 733                 cmd[2] = cmd[3] = 0;
 734                 cmd[4] = 1;
 735         } else
 736                 cmd[2] = cmd[3] = cmd[4] = 0xff;        /* -1 filemarks */
 737         cmd[5] = 0;
 738
 739         DEBC_printk(STp, "Stepping over filemark %s.\n",
 740                     forward ? "forward" : "backward");
 741
 742         SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
 743                            STp->device->request_queue->rq_timeout,
 744                            MAX_RETRIES, 1);
 745         if (!SRpnt)
 746                 return (STp->buffer)->syscall_result;
 747
 748         st_release_request(SRpnt);
 749         SRpnt = NULL;
 750
 751         if ((STp->buffer)->cmdstat.midlevel_result != 0)
 752                 st_printk(KERN_ERR, STp,
 753                           "Stepping over filemark %s failed.\n",
 754                           forward ? "forward" : "backward");
 755
 756         return (STp->buffer)->syscall_result;
 757 }
 758
 759
 760 /* Flush the write buffer (never need to write if variable blocksize). */
 761 static int st_flush_write_buffer(struct scsi_tape * STp)
 762 {
 763         int transfer, blks;
 764         int result;
 765         unsigned char cmd[MAX_COMMAND_SIZE];
 766         struct st_request *SRpnt;
 767         struct st_partstat *STps;
 768
 769         result = write_behind_check(STp);
 770         if (result)
 771                 return result;
 772
 773         result = 0;
 774         if (STp->dirty == 1) {
 775
 776                 transfer = STp->buffer->buffer_bytes;
 777                 DEBC_printk(STp, "Flushing %d bytes.\n", transfer);
 778
 779                 memset(cmd, 0, MAX_COMMAND_SIZE);
 780                 cmd[0] = WRITE_6;
 781                 cmd[1] = 1;
 782                 blks = transfer / STp->block_size;
 783                 cmd[2] = blks >> 16;
 784                 cmd[3] = blks >> 8;
 785                 cmd[4] = blks;
 786
 787                 SRpnt = st_do_scsi(NULL, STp, cmd, transfer, DMA_TO_DEVICE,
 788                                    STp->device->request_queue->rq_timeout,
 789                                    MAX_WRITE_RETRIES, 1);
 790                 if (!SRpnt)
 791                         return (STp->buffer)->syscall_result;
 792
 793                 STps = &(STp->ps[STp->partition]);
 794                 if ((STp->buffer)->syscall_result != 0) {
 795                         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
 796
 797                         if (cmdstatp->have_sense && !cmdstatp->deferred &&
 798                             (cmdstatp->flags & SENSE_EOM) &&
 799                             (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
 800                              cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) &&
 801                             (!cmdstatp->remainder_valid ||
 802                              cmdstatp->uremainder64 == 0)) { /* All written at EOM early warning */
 803                                 STp->dirty = 0;
 804                                 (STp->buffer)->buffer_bytes = 0;
 805                                 if (STps->drv_block >= 0)
 806                                         STps->drv_block += blks;
 807                                 result = (-ENOSPC);
 808                         } else {
 809                                 st_printk(KERN_ERR, STp, "Error on flush.\n");
 810                                 STps->drv_block = (-1);
 811                                 result = (-EIO);
 812                         }
 813                 } else {
 814                         if (STps->drv_block >= 0)
 815                                 STps->drv_block += blks;
 816                         STp->dirty = 0;
 817                         (STp->buffer)->buffer_bytes = 0;
 818                 }
 819                 st_release_request(SRpnt);
 820                 SRpnt = NULL;
 821         }
 822         return result;
 823 }
 824
 825
 826 /* Flush the tape buffer. The tape will be positioned correctly unless
 827    seek_next is true. */
 828 static int flush_buffer(struct scsi_tape *STp, int seek_next)
 829 {
 830         int backspace, result;
 831         struct st_partstat *STps;
 832
 833         /*
 834          * If there was a bus reset, block further access
 835          * to this device.
 836          */
 837         if (STp->pos_unknown)
 838                 return (-EIO);
 839
 840         if (STp->ready != ST_READY)
 841                 return 0;
 842         STps = &(STp->ps[STp->partition]);
 843         if (STps->rw == ST_WRITING)     /* Writing */
 844                 return st_flush_write_buffer(STp);
 845
 846         if (STp->block_size == 0)
 847                 return 0;
 848
 849         backspace = ((STp->buffer)->buffer_bytes +
 850                      (STp->buffer)->read_pointer) / STp->block_size -
 851             ((STp->buffer)->read_pointer + STp->block_size - 1) /
 852             STp->block_size;
 853         (STp->buffer)->buffer_bytes = 0;
 854         (STp->buffer)->read_pointer = 0;
 855         result = 0;
 856         if (!seek_next) {
 857                 if (STps->eof == ST_FM_HIT) {
 858                         result = cross_eof(STp, 0);     /* Back over the EOF hit */
 859                         if (!result)
 860                                 STps->eof = ST_NOEOF;
 861                         else {
 862                                 if (STps->drv_file >= 0)
 863                                         STps->drv_file++;
 864                                 STps->drv_block = 0;
 865                         }
 866                 }
 867                 if (!result && backspace > 0)
 868                         result = st_int_ioctl(STp, MTBSR, backspace);
 869         } else if (STps->eof == ST_FM_HIT) {
 870                 if (STps->drv_file >= 0)
 871                         STps->drv_file++;
 872                 STps->drv_block = 0;
 873                 STps->eof = ST_NOEOF;
 874         }
 875         return result;
 876
 877 }
 878 \f
 879 /* Set the mode parameters */
 880 static int set_mode_densblk(struct scsi_tape * STp, struct st_modedef * STm)
 881 {
 882         int set_it = 0;
 883         unsigned long arg;
 884
 885         if (!STp->density_changed &&
 886             STm->default_density >= 0 &&
 887             STm->default_density != STp->density) {
 888                 arg = STm->default_density;
 889                 set_it = 1;
 890         } else
 891                 arg = STp->density;
 892         arg <<= MT_ST_DENSITY_SHIFT;
 893         if (!STp->blksize_changed &&
 894             STm->default_blksize >= 0 &&
 895             STm->default_blksize != STp->block_size) {
 896                 arg |= STm->default_blksize;
 897                 set_it = 1;
 898         } else
 899                 arg |= STp->block_size;
 900         if (set_it &&
 901             st_int_ioctl(STp, SET_DENS_AND_BLK, arg)) {
 902                 st_printk(KERN_WARNING, STp,
 903                           "Can't set default block size to %d bytes "
 904                           "and density %x.\n",
 905                           STm->default_blksize, STm->default_density);
 906                 if (modes_defined)
 907                         return (-EINVAL);
 908         }
 909         return 0;
 910 }
 911
 912
 913 /* Lock or unlock the drive door. Don't use when st_request allocated. */
 914 static int do_door_lock(struct scsi_tape * STp, int do_lock)
 915 {
 916         int retval;
 917
 918         DEBC_printk(STp, "%socking drive door.\n", do_lock ? "L" : "Unl");
 919
 920         retval = scsi_set_medium_removal(STp->device,
 921                         do_lock ? SCSI_REMOVAL_PREVENT : SCSI_REMOVAL_ALLOW);
 922         if (!retval)
 923                 STp->door_locked = do_lock ? ST_LOCKED_EXPLICIT : ST_UNLOCKED;
 924         else
 925                 STp->door_locked = ST_LOCK_FAILS;
 926         return retval;
 927 }
 928
 929
 930 /* Set the internal state after reset */
 931 static void reset_state(struct scsi_tape *STp)
 932 {
 933         int i;
 934         struct st_partstat *STps;
 935
 936         STp->pos_unknown = 0;
 937         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
 938                 STps = &(STp->ps[i]);
 939                 STps->rw = ST_IDLE;
 940                 STps->eof = ST_NOEOF;
 941                 STps->at_sm = 0;
 942                 STps->last_block_valid = 0;
 943                 STps->drv_block = -1;
 944                 STps->drv_file = -1;
 945         }
 946         if (STp->can_partitions) {
 947                 STp->partition = find_partition(STp);
 948                 if (STp->partition < 0)
 949                         STp->partition = 0;
 950                 STp->new_partition = STp->partition;
 951         }
 952 }
 953 \f
 954 /* Test if the drive is ready. Returns either one of the codes below or a negative system
 955    error code. */
 956 #define CHKRES_READY       0
 957 #define CHKRES_NEW_SESSION 1
 958 #define CHKRES_NOT_READY   2
 959 #define CHKRES_NO_TAPE     3
 960
 961 #define MAX_ATTENTIONS    10
 962
 963 static int test_ready(struct scsi_tape *STp, int do_wait)
 964 {
 965         int attentions, waits, max_wait, scode;
 966         int retval = CHKRES_READY, new_session = 0;
 967         unsigned char cmd[MAX_COMMAND_SIZE];
 968         struct st_request *SRpnt = NULL;
 969         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
 970
 971         max_wait = do_wait ? ST_BLOCK_SECONDS : 0;
 972
 973         for (attentions=waits=0; ; ) {
 974                 memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
 975                 cmd[0] = TEST_UNIT_READY;
 976                 SRpnt = st_do_scsi(SRpnt, STp, cmd, 0, DMA_NONE,
 977                                    STp->long_timeout, MAX_READY_RETRIES, 1);
 978
 979                 if (!SRpnt) {
 980                         retval = (STp->buffer)->syscall_result;
 981                         break;
 982                 }
 983
 984                 if (cmdstatp->have_sense) {
 985
 986                         scode = cmdstatp->sense_hdr.sense_key;
 987
 988                         if (scode == UNIT_ATTENTION) { /* New media? */
 989                                 new_session = 1;
 990                                 if (attentions < MAX_ATTENTIONS) {
 991                                         attentions++;
 992                                         continue;
 993                                 }
 994                                 else {
 995                                         retval = (-EIO);
 996                                         break;
 997                                 }
 998                         }
 999
1000                         if (scode == NOT_READY) {
1001                                 if (waits < max_wait) {
1002                                         if (msleep_interruptible(1000)) {
1003                                                 retval = (-EINTR);
1004                                                 break;
1005                                         }
1006                                         waits++;
1007                                         continue;
1008                                 }
1009                                 else {
1010                                         if ((STp->device)->scsi_level >= SCSI_2 &&
1011                                             cmdstatp->sense_hdr.asc == 0x3a)    /* Check ASC */
1012                                                 retval = CHKRES_NO_TAPE;
1013                                         else
1014                                                 retval = CHKRES_NOT_READY;
1015                                         break;
1016                                 }
1017                         }
1018                 }
1019
1020                 retval = (STp->buffer)->syscall_result;
1021                 if (!retval)
1022                         retval = new_session ? CHKRES_NEW_SESSION : CHKRES_READY;
1023                 break;
1024         }
1025
1026         if (SRpnt != NULL)
1027                 st_release_request(SRpnt);
1028         return retval;
1029 }
1030
1031
1032 /* See if the drive is ready and gather information about the tape. Return values:
1033    < 0   negative error code from errno.h
1034    0     drive ready
1035    1     drive not ready (possibly no tape)
1036 */
1037 static int check_tape(struct scsi_tape *STp, struct file *filp)
1038 {
1039         int i, retval, new_session = 0, do_wait;
1040         unsigned char cmd[MAX_COMMAND_SIZE], saved_cleaning;
1041         unsigned short st_flags = filp->f_flags;
1042         struct st_request *SRpnt = NULL;
1043         struct st_modedef *STm;
1044         struct st_partstat *STps;
1045         struct inode *inode = file_inode(filp);
1046         int mode = TAPE_MODE(inode);
1047
1048         STp->ready = ST_READY;
1049
1050         if (mode != STp->current_mode) {
1051                 DEBC_printk(STp, "Mode change from %d to %d.\n",
1052                             STp->current_mode, mode);
1053                 new_session = 1;
1054                 STp->current_mode = mode;
1055         }
1056         STm = &(STp->modes[STp->current_mode]);
1057
1058         saved_cleaning = STp->cleaning_req;
1059         STp->cleaning_req = 0;
1060
1061         do_wait = ((filp->f_flags & O_NONBLOCK) == 0);
1062         retval = test_ready(STp, do_wait);
1063
1064         if (retval < 0)
1065             goto err_out;
1066
1067         if (retval == CHKRES_NEW_SESSION) {
1068                 STp->pos_unknown = 0;
1069                 STp->partition = STp->new_partition = 0;
1070                 if (STp->can_partitions)
1071                         STp->nbr_partitions = 1; /* This guess will be updated later
1072                                                     if necessary */
1073                 for (i = 0; i < ST_NBR_PARTITIONS; i++) {
1074                         STps = &(STp->ps[i]);
1075                         STps->rw = ST_IDLE;
1076                         STps->eof = ST_NOEOF;
1077                         STps->at_sm = 0;
1078                         STps->last_block_valid = 0;
1079                         STps->drv_block = 0;
1080                         STps->drv_file = 0;
1081                 }
1082                 new_session = 1;
1083         }
1084         else {
1085                 STp->cleaning_req |= saved_cleaning;
1086
1087                 if (retval == CHKRES_NOT_READY || retval == CHKRES_NO_TAPE) {
1088                         if (retval == CHKRES_NO_TAPE)
1089                                 STp->ready = ST_NO_TAPE;
1090                         else
1091                                 STp->ready = ST_NOT_READY;
1092
1093                         STp->density = 0;       /* Clear the erroneous "residue" */
1094                         STp->write_prot = 0;
1095                         STp->block_size = 0;
1096                         STp->ps[0].drv_file = STp->ps[0].drv_block = (-1);
1097                         STp->partition = STp->new_partition = 0;
1098                         STp->door_locked = ST_UNLOCKED;
1099                         return CHKRES_NOT_READY;
1100                 }
1101         }
1102
1103         if (STp->omit_blklims)
1104                 STp->min_block = STp->max_block = (-1);
1105         else {
1106                 memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
1107                 cmd[0] = READ_BLOCK_LIMITS;
1108
1109                 SRpnt = st_do_scsi(SRpnt, STp, cmd, 6, DMA_FROM_DEVICE,
1110                                    STp->device->request_queue->rq_timeout,
1111                                    MAX_READY_RETRIES, 1);
1112                 if (!SRpnt) {
1113                         retval = (STp->buffer)->syscall_result;
1114                         goto err_out;
1115                 }
1116
1117                 if (!SRpnt->result && !STp->buffer->cmdstat.have_sense) {
1118                         STp->max_block = ((STp->buffer)->b_data[1] << 16) |
1119                             ((STp->buffer)->b_data[2] << 8) | (STp->buffer)->b_data[3];
1120                         STp->min_block = ((STp->buffer)->b_data[4] << 8) |
1121                             (STp->buffer)->b_data[5];
1122                         if ( DEB( debugging || ) !STp->inited)
1123                                 st_printk(KERN_INFO, STp,
1124                                           "Block limits %d - %d bytes.\n",
1125                                           STp->min_block, STp->max_block);
1126                 } else {
1127                         STp->min_block = STp->max_block = (-1);
1128                         DEBC_printk(STp, "Can't read block limits.\n");
1129                 }
1130         }
1131
1132         memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
1133         cmd[0] = MODE_SENSE;
1134         cmd[4] = 12;
1135
1136         SRpnt = st_do_scsi(SRpnt, STp, cmd, 12, DMA_FROM_DEVICE,
1137                            STp->device->request_queue->rq_timeout,
1138                            MAX_READY_RETRIES, 1);
1139         if (!SRpnt) {
1140                 retval = (STp->buffer)->syscall_result;
1141                 goto err_out;
1142         }
1143
1144         if ((STp->buffer)->syscall_result != 0) {
1145                 DEBC_printk(STp, "No Mode Sense.\n");
1146                 STp->block_size = ST_DEFAULT_BLOCK;     /* Educated guess (?) */
1147                 (STp->buffer)->syscall_result = 0;      /* Prevent error propagation */
1148                 STp->drv_write_prot = 0;
1149         } else {
1150                 DEBC_printk(STp,"Mode sense. Length %d, "
1151                             "medium %x, WBS %x, BLL %d\n",
1152                             (STp->buffer)->b_data[0],
1153                             (STp->buffer)->b_data[1],
1154                             (STp->buffer)->b_data[2],
1155                             (STp->buffer)->b_data[3]);
1156
1157                 if ((STp->buffer)->b_data[3] >= 8) {
1158                         STp->drv_buffer = ((STp->buffer)->b_data[2] >> 4) & 7;
1159                         STp->density = (STp->buffer)->b_data[4];
1160                         STp->block_size = (STp->buffer)->b_data[9] * 65536 +
1161                             (STp->buffer)->b_data[10] * 256 + (STp->buffer)->b_data[11];
1162                         DEBC_printk(STp, "Density %x, tape length: %x, "
1163                                     "drv buffer: %d\n",
1164                                     STp->density,
1165                                     (STp->buffer)->b_data[5] * 65536 +
1166                                     (STp->buffer)->b_data[6] * 256 +
1167                                     (STp->buffer)->b_data[7],
1168                                     STp->drv_buffer);
1169                 }
1170                 STp->drv_write_prot = ((STp->buffer)->b_data[2] & 0x80) != 0;
1171                 if (!STp->drv_buffer && STp->immediate_filemark) {
1172                         st_printk(KERN_WARNING, STp,
1173                                   "non-buffered tape: disabling "
1174                                   "writing immediate filemarks\n");
1175                         STp->immediate_filemark = 0;
1176                 }
1177         }
1178         st_release_request(SRpnt);
1179         SRpnt = NULL;
1180         STp->inited = 1;
1181
1182         if (STp->block_size > 0)
1183                 (STp->buffer)->buffer_blocks =
1184                         (STp->buffer)->buffer_size / STp->block_size;
1185         else
1186                 (STp->buffer)->buffer_blocks = 1;
1187         (STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
1188
1189         DEBC_printk(STp, "Block size: %d, buffer size: %d (%d blocks).\n",
1190                     STp->block_size, (STp->buffer)->buffer_size,
1191                     (STp->buffer)->buffer_blocks);
1192
1193         if (STp->drv_write_prot) {
1194                 STp->write_prot = 1;
1195
1196                 DEBC_printk(STp, "Write protected\n");
1197
1198                 if (do_wait &&
1199                     ((st_flags & O_ACCMODE) == O_WRONLY ||
1200                      (st_flags & O_ACCMODE) == O_RDWR)) {
1201                         retval = (-EROFS);
1202                         goto err_out;
1203                 }
1204         }
1205
1206         if (STp->can_partitions && STp->nbr_partitions < 1) {
1207                 /* This code is reached when the device is opened for the first time
1208                    after the driver has been initialized with tape in the drive and the
1209                    partition support has been enabled. */
1210                 DEBC_printk(STp, "Updating partition number in status.\n");
1211                 if ((STp->partition = find_partition(STp)) < 0) {
1212                         retval = STp->partition;
1213                         goto err_out;
1214                 }
1215                 STp->new_partition = STp->partition;
1216                 STp->nbr_partitions = 1; /* This guess will be updated when necessary */
1217         }
1218
1219         if (new_session) {      /* Change the drive parameters for the new mode */
1220                 STp->density_changed = STp->blksize_changed = 0;
1221                 STp->compression_changed = 0;
1222                 if (!(STm->defaults_for_writes) &&
1223                     (retval = set_mode_densblk(STp, STm)) < 0)
1224                     goto err_out;
1225
1226                 if (STp->default_drvbuffer != 0xff) {
1227                         if (st_int_ioctl(STp, MTSETDRVBUFFER, STp->default_drvbuffer))
1228                                 st_printk(KERN_WARNING, STp,
1229                                           "Can't set default drive "
1230                                           "buffering to %d.\n",
1231                                           STp->default_drvbuffer);
1232                 }
1233         }
1234
1235         return CHKRES_READY;
1236
1237  err_out:
1238         return retval;
1239 }
1240
1241
1242 \f/* Open the device. Needs to take the BKL only because of incrementing the SCSI host
1243    module count. */
1244 static int st_open(struct inode *inode, struct file *filp)
1245 {
1246         int i, retval = (-EIO);
1247         int resumed = 0;
1248         struct scsi_tape *STp;
1249         struct st_partstat *STps;
1250         int dev = TAPE_NR(inode);
1251
1252         /*
1253          * We really want to do nonseekable_open(inode, filp); here, but some
1254          * versions of tar incorrectly call lseek on tapes and bail out if that
1255          * fails.  So we disallow pread() and pwrite(), but permit lseeks.
1256          */
1257         filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
1258
1259         if (!(STp = scsi_tape_get(dev))) {
1260                 return -ENXIO;
1261         }
1262
1263         filp->private_data = STp;
1264
1265         spin_lock(&st_use_lock);
1266         if (STp->in_use) {
1267                 spin_unlock(&st_use_lock);
1268                 DEBC_printk(STp, "Device already in use.\n");
1269                 scsi_tape_put(STp);
1270                 return (-EBUSY);
1271         }
1272
1273         STp->in_use = 1;
1274         spin_unlock(&st_use_lock);
1275         STp->rew_at_close = STp->autorew_dev = (iminor(inode) & 0x80) == 0;
1276
1277         if (scsi_autopm_get_device(STp->device) < 0) {
1278                 retval = -EIO;
1279                 goto err_out;
1280         }
1281         resumed = 1;
1282         if (!scsi_block_when_processing_errors(STp->device)) {
1283                 retval = (-ENXIO);
1284                 goto err_out;
1285         }
1286
1287         /* See that we have at least a one page buffer available */
1288         if (!enlarge_buffer(STp->buffer, PAGE_SIZE, STp->restr_dma)) {
1289                 st_printk(KERN_WARNING, STp,
1290                           "Can't allocate one page tape buffer.\n");
1291                 retval = (-EOVERFLOW);
1292                 goto err_out;
1293         }
1294
1295         (STp->buffer)->cleared = 0;
1296         (STp->buffer)->writing = 0;
1297         (STp->buffer)->syscall_result = 0;
1298
1299         STp->write_prot = ((filp->f_flags & O_ACCMODE) == O_RDONLY);
1300
1301         STp->dirty = 0;
1302         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
1303                 STps = &(STp->ps[i]);
1304                 STps->rw = ST_IDLE;
1305         }
1306         STp->try_dio_now = STp->try_dio;
1307         STp->recover_count = 0;
1308         DEB( STp->nbr_waits = STp->nbr_finished = 0;
1309              STp->nbr_requests = STp->nbr_dio = STp->nbr_pages = 0; )
1310
1311         retval = check_tape(STp, filp);
1312         if (retval < 0)
1313                 goto err_out;
1314         if ((filp->f_flags & O_NONBLOCK) == 0 &&
1315             retval != CHKRES_READY) {
1316                 if (STp->ready == NO_TAPE)
1317                         retval = (-ENOMEDIUM);
1318                 else
1319                         retval = (-EIO);
1320                 goto err_out;
1321         }
1322         return 0;
1323
1324  err_out:
1325         normalize_buffer(STp->buffer);
1326         spin_lock(&st_use_lock);
1327         STp->in_use = 0;
1328         spin_unlock(&st_use_lock);
1329         if (resumed)
1330                 scsi_autopm_put_device(STp->device);
1331         scsi_tape_put(STp);
1332         return retval;
1333
1334 }
1335 \f
1336
1337 /* Flush the tape buffer before close */
1338 static int st_flush(struct file *filp, fl_owner_t id)
1339 {
1340         int result = 0, result2;
1341         unsigned char cmd[MAX_COMMAND_SIZE];
1342         struct st_request *SRpnt;
1343         struct scsi_tape *STp = filp->private_data;
1344         struct st_modedef *STm = &(STp->modes[STp->current_mode]);
1345         struct st_partstat *STps = &(STp->ps[STp->partition]);
1346
1347         if (file_count(filp) > 1)
1348                 return 0;
1349
1350         if (STps->rw == ST_WRITING && !STp->pos_unknown) {
1351                 result = st_flush_write_buffer(STp);
1352                 if (result != 0 && result != (-ENOSPC))
1353                         goto out;
1354         }
1355
1356         if (STp->can_partitions &&
1357             (result2 = switch_partition(STp)) < 0) {
1358                 DEBC_printk(STp, "switch_partition at close failed.\n");
1359                 if (result == 0)
1360                         result = result2;
1361                 goto out;
1362         }
1363
1364         DEBC( if (STp->nbr_requests)
1365                 st_printk(KERN_DEBUG, STp,
1366                           "Number of r/w requests %d, dio used in %d, "
1367                           "pages %d.\n", STp->nbr_requests, STp->nbr_dio,
1368                           STp->nbr_pages));
1369
1370         if (STps->rw == ST_WRITING && !STp->pos_unknown) {
1371                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1372
1373 #if DEBUG
1374                 DEBC_printk(STp, "Async write waits %d, finished %d.\n",
1375                             STp->nbr_waits, STp->nbr_finished);
1376 #endif
1377                 memset(cmd, 0, MAX_COMMAND_SIZE);
1378                 cmd[0] = WRITE_FILEMARKS;
1379                 if (STp->immediate_filemark)
1380                         cmd[1] = 1;
1381                 cmd[4] = 1 + STp->two_fm;
1382
1383                 SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
1384                                    STp->device->request_queue->rq_timeout,
1385                                    MAX_WRITE_RETRIES, 1);
1386                 if (!SRpnt) {
1387                         result = (STp->buffer)->syscall_result;
1388                         goto out;
1389                 }
1390
1391                 if (STp->buffer->syscall_result == 0 ||
1392                     (cmdstatp->have_sense && !cmdstatp->deferred &&
1393                      (cmdstatp->flags & SENSE_EOM) &&
1394                      (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
1395                       cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) &&
1396                      (!cmdstatp->remainder_valid || cmdstatp->uremainder64 == 0))) {
1397                         /* Write successful at EOM */
1398                         st_release_request(SRpnt);
1399                         SRpnt = NULL;
1400                         if (STps->drv_file >= 0)
1401                                 STps->drv_file++;
1402                         STps->drv_block = 0;
1403                         if (STp->two_fm)
1404                                 cross_eof(STp, 0);
1405                         STps->eof = ST_FM;
1406                 }
1407                 else { /* Write error */
1408                         st_release_request(SRpnt);
1409                         SRpnt = NULL;
1410                         st_printk(KERN_ERR, STp,
1411                                   "Error on write filemark.\n");
1412                         if (result == 0)
1413                                 result = (-EIO);
1414                 }
1415
1416                 DEBC_printk(STp, "Buffer flushed, %d EOF(s) written\n", cmd[4]);
1417         } else if (!STp->rew_at_close) {
1418                 STps = &(STp->ps[STp->partition]);
1419                 if (!STm->sysv || STps->rw != ST_READING) {
1420                         if (STp->can_bsr)
1421                                 result = flush_buffer(STp, 0);
1422                         else if (STps->eof == ST_FM_HIT) {
1423                                 result = cross_eof(STp, 0);
1424                                 if (result) {
1425                                         if (STps->drv_file >= 0)
1426                                                 STps->drv_file++;
1427                                         STps->drv_block = 0;
1428                                         STps->eof = ST_FM;
1429                                 } else
1430                                         STps->eof = ST_NOEOF;
1431                         }
1432                 } else if ((STps->eof == ST_NOEOF &&
1433                             !(result = cross_eof(STp, 1))) ||
1434                            STps->eof == ST_FM_HIT) {
1435                         if (STps->drv_file >= 0)
1436                                 STps->drv_file++;
1437                         STps->drv_block = 0;
1438                         STps->eof = ST_FM;
1439                 }
1440         }
1441
1442       out:
1443         if (STp->rew_at_close) {
1444                 result2 = st_int_ioctl(STp, MTREW, 1);
1445                 if (result == 0)
1446                         result = result2;
1447         }
1448         return result;
1449 }
1450
1451
1452 /* Close the device and release it. BKL is not needed: this is the only thread
1453    accessing this tape. */
1454 static int st_release(struct inode *inode, struct file *filp)
1455 {
1456         int result = 0;
1457         struct scsi_tape *STp = filp->private_data;
1458
1459         if (STp->door_locked == ST_LOCKED_AUTO)
1460                 do_door_lock(STp, 0);
1461
1462         normalize_buffer(STp->buffer);
1463         spin_lock(&st_use_lock);
1464         STp->in_use = 0;
1465         spin_unlock(&st_use_lock);
1466         scsi_autopm_put_device(STp->device);
1467         scsi_tape_put(STp);
1468
1469         return result;
1470 }
1471 \f
1472 /* The checks common to both reading and writing */
1473 static ssize_t rw_checks(struct scsi_tape *STp, struct file *filp, size_t count)
1474 {
1475         ssize_t retval = 0;
1476
1477         /*
1478          * If we are in the middle of error recovery, don't let anyone
1479          * else try and use this device.  Also, if error recovery fails, it
1480          * may try and take the device offline, in which case all further
1481          * access to the device is prohibited.
1482          */
1483         if (!scsi_block_when_processing_errors(STp->device)) {
1484                 retval = (-ENXIO);
1485                 goto out;
1486         }
1487
1488         if (STp->ready != ST_READY) {
1489                 if (STp->ready == ST_NO_TAPE)
1490                         retval = (-ENOMEDIUM);
1491                 else
1492                         retval = (-EIO);
1493                 goto out;
1494         }
1495
1496         if (! STp->modes[STp->current_mode].defined) {
1497                 retval = (-ENXIO);
1498                 goto out;
1499         }
1500
1501
1502         /*
1503          * If there was a bus reset, block further access
1504          * to this device.
1505          */
1506         if (STp->pos_unknown) {
1507                 retval = (-EIO);
1508                 goto out;
1509         }
1510
1511         if (count == 0)
1512                 goto out;
1513
1514         DEB(
1515         if (!STp->in_use) {
1516                 st_printk(ST_DEB_MSG, STp,
1517                           "Incorrect device.\n");
1518                 retval = (-EIO);
1519                 goto out;
1520         } ) /* end DEB */
1521
1522         if (STp->can_partitions &&
1523             (retval = switch_partition(STp)) < 0)
1524                 goto out;
1525
1526         if (STp->block_size == 0 && STp->max_block > 0 &&
1527             (count < STp->min_block || count > STp->max_block)) {
1528                 retval = (-EINVAL);
1529                 goto out;
1530         }
1531
1532         if (STp->do_auto_lock && STp->door_locked == ST_UNLOCKED &&
1533             !do_door_lock(STp, 1))
1534                 STp->door_locked = ST_LOCKED_AUTO;
1535
1536  out:
1537         return retval;
1538 }
1539
1540
1541 static int setup_buffering(struct scsi_tape *STp, const char __user *buf,
1542                            size_t count, int is_read)
1543 {
1544         int i, bufsize, retval = 0;
1545         struct st_buffer *STbp = STp->buffer;
1546
1547         if (is_read)
1548                 i = STp->try_dio_now && try_rdio;
1549         else
1550                 i = STp->try_dio_now && try_wdio;
1551
1552         if (i && ((unsigned long)buf & queue_dma_alignment(
1553                                         STp->device->request_queue)) == 0) {
1554                 i = sgl_map_user_pages(STbp, STbp->use_sg, (unsigned long)buf,
1555                                        count, (is_read ? READ : WRITE));
1556                 if (i > 0) {
1557                         STbp->do_dio = i;
1558                         STbp->buffer_bytes = 0;   /* can be used as transfer counter */
1559                 }
1560                 else
1561                         STbp->do_dio = 0;  /* fall back to buffering with any error */
1562                 STbp->sg_segs = STbp->do_dio;
1563                 DEB(
1564                      if (STbp->do_dio) {
1565                         STp->nbr_dio++;
1566                         STp->nbr_pages += STbp->do_dio;
1567                      }
1568                 )
1569         } else
1570                 STbp->do_dio = 0;
1571         DEB( STp->nbr_requests++; )
1572
1573         if (!STbp->do_dio) {
1574                 if (STp->block_size)
1575                         bufsize = STp->block_size > st_fixed_buffer_size ?
1576                                 STp->block_size : st_fixed_buffer_size;
1577                 else {
1578                         bufsize = count;
1579                         /* Make sure that data from previous user is not leaked even if
1580                            HBA does not return correct residual */
1581                         if (is_read && STp->sili && !STbp->cleared)
1582                                 clear_buffer(STbp);
1583                 }
1584
1585                 if (bufsize > STbp->buffer_size &&
1586                     !enlarge_buffer(STbp, bufsize, STp->restr_dma)) {
1587                         st_printk(KERN_WARNING, STp,
1588                                   "Can't allocate %d byte tape buffer.\n",
1589                                   bufsize);
1590                         retval = (-EOVERFLOW);
1591                         goto out;
1592                 }
1593                 if (STp->block_size)
1594                         STbp->buffer_blocks = bufsize / STp->block_size;
1595         }
1596
1597  out:
1598         return retval;
1599 }
1600
1601
1602 /* Can be called more than once after each setup_buffer() */
1603 static void release_buffering(struct scsi_tape *STp, int is_read)
1604 {
1605         struct st_buffer *STbp;
1606
1607         STbp = STp->buffer;
1608         if (STbp->do_dio) {
1609                 sgl_unmap_user_pages(STbp, STbp->do_dio, is_read);
1610                 STbp->do_dio = 0;
1611                 STbp->sg_segs = 0;
1612         }
1613 }
1614
1615
1616 /* Write command */
1617 static ssize_t
1618 st_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
1619 {
1620         ssize_t total;
1621         ssize_t i, do_count, blks, transfer;
1622         ssize_t retval;
1623         int undone, retry_eot = 0, scode;
1624         int async_write;
1625         unsigned char cmd[MAX_COMMAND_SIZE];
1626         const char __user *b_point;
1627         struct st_request *SRpnt = NULL;
1628         struct scsi_tape *STp = filp->private_data;
1629         struct st_modedef *STm;
1630         struct st_partstat *STps;
1631         struct st_buffer *STbp;
1632
1633         if (mutex_lock_interruptible(&STp->lock))
1634                 return -ERESTARTSYS;
1635
1636         retval = rw_checks(STp, filp, count);
1637         if (retval || count == 0)
1638                 goto out;
1639
1640         /* Write must be integral number of blocks */
1641         if (STp->block_size != 0 && (count % STp->block_size) != 0) {
1642                 st_printk(KERN_WARNING, STp,
1643                           "Write not multiple of tape block size.\n");
1644                 retval = (-EINVAL);
1645                 goto out;
1646         }
1647
1648         STm = &(STp->modes[STp->current_mode]);
1649         STps = &(STp->ps[STp->partition]);
1650
1651         if (STp->write_prot) {
1652                 retval = (-EACCES);
1653                 goto out;
1654         }
1655
1656
1657         if (STps->rw == ST_READING) {
1658                 retval = flush_buffer(STp, 0);
1659                 if (retval)
1660                         goto out;
1661                 STps->rw = ST_WRITING;
1662         } else if (STps->rw != ST_WRITING &&
1663                    STps->drv_file == 0 && STps->drv_block == 0) {
1664                 if ((retval = set_mode_densblk(STp, STm)) < 0)
1665                         goto out;
1666                 if (STm->default_compression != ST_DONT_TOUCH &&
1667                     !(STp->compression_changed)) {
1668                         if (st_compression(STp, (STm->default_compression == ST_YES))) {
1669                                 st_printk(KERN_WARNING, STp,
1670                                           "Can't set default compression.\n");
1671                                 if (modes_defined) {
1672                                         retval = (-EINVAL);
1673                                         goto out;
1674                                 }
1675                         }
1676                 }
1677         }
1678
1679         STbp = STp->buffer;
1680         i = write_behind_check(STp);
1681         if (i) {
1682                 if (i == -ENOSPC)
1683                         STps->eof = ST_EOM_OK;
1684                 else
1685                         STps->eof = ST_EOM_ERROR;
1686         }
1687
1688         if (STps->eof == ST_EOM_OK) {
1689                 STps->eof = ST_EOD_1;  /* allow next write */
1690                 retval = (-ENOSPC);
1691                 goto out;
1692         }
1693         else if (STps->eof == ST_EOM_ERROR) {
1694                 retval = (-EIO);
1695                 goto out;
1696         }
1697
1698         /* Check the buffer readability in cases where copy_user might catch
1699            the problems after some tape movement. */
1700         if (STp->block_size != 0 &&
1701             !STbp->do_dio &&
1702             (copy_from_user(&i, buf, 1) != 0 ||
1703              copy_from_user(&i, buf + count - 1, 1) != 0)) {
1704                 retval = (-EFAULT);
1705                 goto out;
1706         }
1707
1708         retval = setup_buffering(STp, buf, count, 0);
1709         if (retval)
1710                 goto out;
1711
1712         total = count;
1713
1714         memset(cmd, 0, MAX_COMMAND_SIZE);
1715         cmd[0] = WRITE_6;
1716         cmd[1] = (STp->block_size != 0);
1717
1718         STps->rw = ST_WRITING;
1719
1720         b_point = buf;
1721         while (count > 0 && !retry_eot) {
1722
1723                 if (STbp->do_dio) {
1724                         do_count = count;
1725                 }
1726                 else {
1727                         if (STp->block_size == 0)
1728                                 do_count = count;
1729                         else {
1730                                 do_count = STbp->buffer_blocks * STp->block_size -
1731                                         STbp->buffer_bytes;
1732                                 if (do_count > count)
1733                                         do_count = count;
1734                         }
1735
1736                         i = append_to_buffer(b_point, STbp, do_count);
1737                         if (i) {
1738                                 retval = i;
1739                                 goto out;
1740                         }
1741                 }
1742                 count -= do_count;
1743                 b_point += do_count;
1744
1745                 async_write = STp->block_size == 0 && !STbp->do_dio &&
1746                         STm->do_async_writes && STps->eof < ST_EOM_OK;
1747
1748                 if (STp->block_size != 0 && STm->do_buffer_writes &&
1749                     !(STp->try_dio_now && try_wdio) && STps->eof < ST_EOM_OK &&
1750                     STbp->buffer_bytes < STbp->buffer_size) {
1751                         STp->dirty = 1;
1752                         /* Don't write a buffer that is not full enough. */
1753                         if (!async_write && count == 0)
1754                                 break;
1755                 }
1756
1757         retry_write:
1758                 if (STp->block_size == 0)
1759                         blks = transfer = do_count;
1760                 else {
1761                         if (!STbp->do_dio)
1762                                 blks = STbp->buffer_bytes;
1763                         else
1764                                 blks = do_count;
1765                         blks /= STp->block_size;
1766                         transfer = blks * STp->block_size;
1767                 }
1768                 cmd[2] = blks >> 16;
1769                 cmd[3] = blks >> 8;
1770                 cmd[4] = blks;
1771
1772                 SRpnt = st_do_scsi(SRpnt, STp, cmd, transfer, DMA_TO_DEVICE,
1773                                    STp->device->request_queue->rq_timeout,
1774                                    MAX_WRITE_RETRIES, !async_write);
1775                 if (!SRpnt) {
1776                         retval = STbp->syscall_result;
1777                         goto out;
1778                 }
1779                 if (async_write && !STbp->syscall_result) {
1780                         STbp->writing = transfer;
1781                         STp->dirty = !(STbp->writing ==
1782                                        STbp->buffer_bytes);
1783                         SRpnt = NULL;  /* Prevent releasing this request! */
1784                         DEB( STp->write_pending = 1; )
1785                         break;
1786                 }
1787
1788                 if (STbp->syscall_result != 0) {
1789                         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1790
1791                         DEBC_printk(STp, "Error on write:\n");
1792                         if (cmdstatp->have_sense && (cmdstatp->flags & SENSE_EOM)) {
1793                                 scode = cmdstatp->sense_hdr.sense_key;
1794                                 if (cmdstatp->remainder_valid)
1795                                         undone = (int)cmdstatp->uremainder64;
1796                                 else if (STp->block_size == 0 &&
1797                                          scode == VOLUME_OVERFLOW)
1798                                         undone = transfer;
1799                                 else
1800                                         undone = 0;
1801                                 if (STp->block_size != 0)
1802                                         undone *= STp->block_size;
1803                                 if (undone <= do_count) {
1804                                         /* Only data from this write is not written */
1805                                         count += undone;
1806                                         b_point -= undone;
1807                                         do_count -= undone;
1808                                         if (STp->block_size)
1809                                                 blks = (transfer - undone) / STp->block_size;
1810                                         STps->eof = ST_EOM_OK;
1811                                         /* Continue in fixed block mode if all written
1812                                            in this request but still something left to write
1813                                            (retval left to zero)
1814                                         */
1815                                         if (STp->block_size == 0 ||
1816                                             undone > 0 || count == 0)
1817                                                 retval = (-ENOSPC); /* EOM within current request */
1818                                         DEBC_printk(STp, "EOM with %d "
1819                                                     "bytes unwritten.\n",
1820                                                     (int)count);
1821                                 } else {
1822                                         /* EOT within data buffered earlier (possible only
1823                                            in fixed block mode without direct i/o) */
1824                                         if (!retry_eot && !cmdstatp->deferred &&
1825                                             (scode == NO_SENSE || scode == RECOVERED_ERROR)) {
1826                                                 move_buffer_data(STp->buffer, transfer - undone);
1827                                                 retry_eot = 1;
1828                                                 if (STps->drv_block >= 0) {
1829                                                         STps->drv_block += (transfer - undone) /
1830                                                                 STp->block_size;
1831                                                 }
1832                                                 STps->eof = ST_EOM_OK;
1833                                                 DEBC_printk(STp, "Retry "
1834                                                             "write of %d "
1835                                                             "bytes at EOM.\n",
1836                                                             STp->buffer->buffer_bytes);
1837                                                 goto retry_write;
1838                                         }
1839                                         else {
1840                                                 /* Either error within data buffered by driver or
1841                                                    failed retry */
1842                                                 count -= do_count;
1843                                                 blks = do_count = 0;
1844                                                 STps->eof = ST_EOM_ERROR;
1845                                                 STps->drv_block = (-1); /* Too cautious? */
1846                                                 retval = (-EIO);        /* EOM for old data */
1847                                                 DEBC_printk(STp, "EOM with "
1848                                                             "lost data.\n");
1849                                         }
1850                                 }
1851                         } else {
1852                                 count += do_count;
1853                                 STps->drv_block = (-1);         /* Too cautious? */
1854                                 retval = STbp->syscall_result;
1855                         }
1856
1857                 }
1858
1859                 if (STps->drv_block >= 0) {
1860                         if (STp->block_size == 0)
1861                                 STps->drv_block += (do_count > 0);
1862                         else
1863                                 STps->drv_block += blks;
1864                 }
1865
1866                 STbp->buffer_bytes = 0;
1867                 STp->dirty = 0;
1868
1869                 if (retval || retry_eot) {
1870                         if (count < total)
1871                                 retval = total - count;
1872                         goto out;
1873                 }
1874         }
1875
1876         if (STps->eof == ST_EOD_1)
1877                 STps->eof = ST_EOM_OK;
1878         else if (STps->eof != ST_EOM_OK)
1879                 STps->eof = ST_NOEOF;
1880         retval = total - count;
1881
1882  out:
1883         if (SRpnt != NULL)
1884                 st_release_request(SRpnt);
1885         release_buffering(STp, 0);
1886         mutex_unlock(&STp->lock);
1887
1888         return retval;
1889 }
1890 \f
1891 /* Read data from the tape. Returns zero in the normal case, one if the
1892    eof status has changed, and the negative error code in case of a
1893    fatal error. Otherwise updates the buffer and the eof state.
1894
1895    Does release user buffer mapping if it is set.
1896 */
1897 static long read_tape(struct scsi_tape *STp, long count,
1898                       struct st_request ** aSRpnt)
1899 {
1900         int transfer, blks, bytes;
1901         unsigned char cmd[MAX_COMMAND_SIZE];
1902         struct st_request *SRpnt;
1903         struct st_modedef *STm;
1904         struct st_partstat *STps;
1905         struct st_buffer *STbp;
1906         int retval = 0;
1907
1908         if (count == 0)
1909                 return 0;
1910
1911         STm = &(STp->modes[STp->current_mode]);
1912         STps = &(STp->ps[STp->partition]);
1913         if (STps->eof == ST_FM_HIT)
1914                 return 1;
1915         STbp = STp->buffer;
1916
1917         if (STp->block_size == 0)
1918                 blks = bytes = count;
1919         else {
1920                 if (!(STp->try_dio_now && try_rdio) && STm->do_read_ahead) {
1921                         blks = (STp->buffer)->buffer_blocks;
1922                         bytes = blks * STp->block_size;
1923                 } else {
1924                         bytes = count;
1925                         if (!STbp->do_dio && bytes > (STp->buffer)->buffer_size)
1926                                 bytes = (STp->buffer)->buffer_size;
1927                         blks = bytes / STp->block_size;
1928                         bytes = blks * STp->block_size;
1929                 }
1930         }
1931
1932         memset(cmd, 0, MAX_COMMAND_SIZE);
1933         cmd[0] = READ_6;
1934         cmd[1] = (STp->block_size != 0);
1935         if (!cmd[1] && STp->sili)
1936                 cmd[1] |= 2;
1937         cmd[2] = blks >> 16;
1938         cmd[3] = blks >> 8;
1939         cmd[4] = blks;
1940
1941         SRpnt = *aSRpnt;
1942         SRpnt = st_do_scsi(SRpnt, STp, cmd, bytes, DMA_FROM_DEVICE,
1943                            STp->device->request_queue->rq_timeout,
1944                            MAX_RETRIES, 1);
1945         release_buffering(STp, 1);
1946         *aSRpnt = SRpnt;
1947         if (!SRpnt)
1948                 return STbp->syscall_result;
1949
1950         STbp->read_pointer = 0;
1951         STps->at_sm = 0;
1952
1953         /* Something to check */
1954         if (STbp->syscall_result) {
1955                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1956
1957                 retval = 1;
1958                 DEBC_printk(STp,
1959                             "Sense: %2x %2x %2x %2x %2x %2x %2x %2x\n",
1960                             SRpnt->sense[0], SRpnt->sense[1],
1961                             SRpnt->sense[2], SRpnt->sense[3],
1962                             SRpnt->sense[4], SRpnt->sense[5],
1963                             SRpnt->sense[6], SRpnt->sense[7]);
1964                 if (cmdstatp->have_sense) {
1965
1966                         if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
1967                                 cmdstatp->flags &= 0xcf;        /* No need for EOM in this case */
1968
1969                         if (cmdstatp->flags != 0) { /* EOF, EOM, or ILI */
1970                                 /* Compute the residual count */
1971                                 if (cmdstatp->remainder_valid)
1972                                         transfer = (int)cmdstatp->uremainder64;
1973                                 else
1974                                         transfer = 0;
1975                                 if (cmdstatp->sense_hdr.sense_key == MEDIUM_ERROR) {
1976                                         if (STp->block_size == 0)
1977                                                 transfer = bytes;
1978                                         /* Some drives set ILI with MEDIUM ERROR */
1979                                         cmdstatp->flags &= ~SENSE_ILI;
1980                                 }
1981
1982                                 if (cmdstatp->flags & SENSE_ILI) {      /* ILI */
1983                                         if (STp->block_size == 0 &&
1984                                             transfer < 0) {
1985                                                 st_printk(KERN_NOTICE, STp,
1986                                                           "Failed to read %d "
1987                                                           "byte block with %d "
1988                                                           "byte transfer.\n",
1989                                                           bytes - transfer,
1990                                                           bytes);
1991                                                 if (STps->drv_block >= 0)
1992                                                         STps->drv_block += 1;
1993                                                 STbp->buffer_bytes = 0;
1994                                                 return (-ENOMEM);
1995                                         } else if (STp->block_size == 0) {
1996                                                 STbp->buffer_bytes = bytes - transfer;
1997                                         } else {
1998                                                 st_release_request(SRpnt);
1999                                                 SRpnt = *aSRpnt = NULL;
2000                                                 if (transfer == blks) { /* We did not get anything, error */
2001                                                         st_printk(KERN_NOTICE, STp,
2002                                                                   "Incorrect "
2003                                                                   "block size.\n");
2004                                                         if (STps->drv_block >= 0)
2005                                                                 STps->drv_block += blks - transfer + 1;
2006                                                         st_int_ioctl(STp, MTBSR, 1);
2007                                                         return (-EIO);
2008                                                 }
2009                                                 /* We have some data, deliver it */
2010                                                 STbp->buffer_bytes = (blks - transfer) *
2011                                                     STp->block_size;
2012                                                 DEBC_printk(STp, "ILI but "
2013                                                             "enough data "
2014                                                             "received %ld "
2015                                                             "%d.\n", count,
2016                                                             STbp->buffer_bytes);
2017                                                 if (STps->drv_block >= 0)
2018                                                         STps->drv_block += 1;
2019                                                 if (st_int_ioctl(STp, MTBSR, 1))
2020                                                         return (-EIO);
2021                                         }
2022                                 } else if (cmdstatp->flags & SENSE_FMK) {       /* FM overrides EOM */
2023                                         if (STps->eof != ST_FM_HIT)
2024                                                 STps->eof = ST_FM_HIT;
2025                                         else
2026                                                 STps->eof = ST_EOD_2;
2027                                         if (STp->block_size == 0)
2028                                                 STbp->buffer_bytes = 0;
2029                                         else
2030                                                 STbp->buffer_bytes =
2031                                                     bytes - transfer * STp->block_size;
2032                                         DEBC_printk(STp, "EOF detected (%d "
2033                                                     "bytes read).\n",
2034                                                     STbp->buffer_bytes);
2035                                 } else if (cmdstatp->flags & SENSE_EOM) {
2036                                         if (STps->eof == ST_FM)
2037                                                 STps->eof = ST_EOD_1;
2038                                         else
2039                                                 STps->eof = ST_EOM_OK;
2040                                         if (STp->block_size == 0)
2041                                                 STbp->buffer_bytes = bytes - transfer;
2042                                         else
2043                                                 STbp->buffer_bytes =
2044                                                     bytes - transfer * STp->block_size;
2045
2046                                         DEBC_printk(STp, "EOM detected (%d "
2047                                                     "bytes read).\n",
2048                                                     STbp->buffer_bytes);
2049                                 }
2050                         }
2051                         /* end of EOF, EOM, ILI test */
2052                         else {  /* nonzero sense key */
2053                                 DEBC_printk(STp, "Tape error while reading.\n");
2054                                 STps->drv_block = (-1);
2055                                 if (STps->eof == ST_FM &&
2056                                     cmdstatp->sense_hdr.sense_key == BLANK_CHECK) {
2057                                         DEBC_printk(STp, "Zero returned for "
2058                                                     "first BLANK CHECK "
2059                                                     "after EOF.\n");
2060                                         STps->eof = ST_EOD_2;   /* First BLANK_CHECK after FM */
2061                                 } else  /* Some other extended sense code */
2062                                         retval = (-EIO);
2063                         }
2064
2065                         if (STbp->buffer_bytes < 0)  /* Caused by bogus sense data */
2066                                 STbp->buffer_bytes = 0;
2067                 }
2068                 /* End of extended sense test */
2069                 else {          /* Non-extended sense */
2070                         retval = STbp->syscall_result;
2071                 }
2072
2073         }
2074         /* End of error handling */
2075         else {                  /* Read successful */
2076                 STbp->buffer_bytes = bytes;
2077                 if (STp->sili) /* In fixed block mode residual is always zero here */
2078                         STbp->buffer_bytes -= STp->buffer->cmdstat.residual;
2079         }
2080
2081         if (STps->drv_block >= 0) {
2082                 if (STp->block_size == 0)
2083                         STps->drv_block++;
2084                 else
2085                         STps->drv_block += STbp->buffer_bytes / STp->block_size;
2086         }
2087         return retval;
2088 }
2089 \f
2090
2091 /* Read command */
2092 static ssize_t
2093 st_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
2094 {
2095         ssize_t total;
2096         ssize_t retval = 0;
2097         ssize_t i, transfer;
2098         int special, do_dio = 0;
2099         struct st_request *SRpnt = NULL;
2100         struct scsi_tape *STp = filp->private_data;
2101         struct st_modedef *STm;
2102         struct st_partstat *STps;
2103         struct st_buffer *STbp = STp->buffer;
2104
2105         if (mutex_lock_interruptible(&STp->lock))
2106                 return -ERESTARTSYS;
2107
2108         retval = rw_checks(STp, filp, count);
2109         if (retval || count == 0)
2110                 goto out;
2111
2112         STm = &(STp->modes[STp->current_mode]);
2113         if (STp->block_size != 0 && (count % STp->block_size) != 0) {
2114                 if (!STm->do_read_ahead) {
2115                         retval = (-EINVAL);     /* Read must be integral number of blocks */
2116                         goto out;
2117                 }
2118                 STp->try_dio_now = 0;  /* Direct i/o can't handle split blocks */
2119         }
2120
2121         STps = &(STp->ps[STp->partition]);
2122         if (STps->rw == ST_WRITING) {
2123                 retval = flush_buffer(STp, 0);
2124                 if (retval)
2125                         goto out;
2126                 STps->rw = ST_READING;
2127         }
2128         DEB(
2129         if (debugging && STps->eof != ST_NOEOF)
2130                 st_printk(ST_DEB_MSG, STp,
2131                           "EOF/EOM flag up (%d). Bytes %d\n",
2132                           STps->eof, STbp->buffer_bytes);
2133         ) /* end DEB */
2134
2135         retval = setup_buffering(STp, buf, count, 1);
2136         if (retval)
2137                 goto out;
2138         do_dio = STbp->do_dio;
2139
2140         if (STbp->buffer_bytes == 0 &&
2141             STps->eof >= ST_EOD_1) {
2142                 if (STps->eof < ST_EOD) {
2143                         STps->eof += 1;
2144                         retval = 0;
2145                         goto out;
2146                 }
2147                 retval = (-EIO);        /* EOM or Blank Check */
2148                 goto out;
2149         }
2150
2151         if (do_dio) {
2152                 /* Check the buffer writability before any tape movement. Don't alter
2153                    buffer data. */
2154                 if (copy_from_user(&i, buf, 1) != 0 ||
2155                     copy_to_user(buf, &i, 1) != 0 ||
2156                     copy_from_user(&i, buf + count - 1, 1) != 0 ||
2157                     copy_to_user(buf + count - 1, &i, 1) != 0) {
2158                         retval = (-EFAULT);
2159                         goto out;
2160                 }
2161         }
2162
2163         STps->rw = ST_READING;
2164
2165
2166         /* Loop until enough data in buffer or a special condition found */
2167         for (total = 0, special = 0; total < count && !special;) {
2168
2169                 /* Get new data if the buffer is empty */
2170                 if (STbp->buffer_bytes == 0) {
2171                         special = read_tape(STp, count - total, &SRpnt);
2172                         if (special < 0) {      /* No need to continue read */
2173                                 retval = special;
2174                                 goto out;
2175                         }
2176                 }
2177
2178                 /* Move the data from driver buffer to user buffer */
2179                 if (STbp->buffer_bytes > 0) {
2180                         DEB(
2181                         if (debugging && STps->eof != ST_NOEOF)
2182                                 st_printk(ST_DEB_MSG, STp,
2183                                           "EOF up (%d). Left %d, needed %d.\n",
2184                                           STps->eof, STbp->buffer_bytes,
2185                                           (int)(count - total));
2186                         ) /* end DEB */
2187                         transfer = STbp->buffer_bytes < count - total ?
2188                             STbp->buffer_bytes : count - total;
2189                         if (!do_dio) {
2190                                 i = from_buffer(STbp, buf, transfer);
2191                                 if (i) {
2192                                         retval = i;
2193                                         goto out;
2194                                 }
2195                         }
2196                         buf += transfer;
2197                         total += transfer;
2198                 }
2199
2200                 if (STp->block_size == 0)
2201                         break;  /* Read only one variable length block */
2202
2203         }                       /* for (total = 0, special = 0;
2204                                    total < count && !special; ) */
2205
2206         /* Change the eof state if no data from tape or buffer */
2207         if (total == 0) {
2208                 if (STps->eof == ST_FM_HIT) {
2209                         STps->eof = ST_FM;
2210                         STps->drv_block = 0;
2211                         if (STps->drv_file >= 0)
2212                                 STps->drv_file++;
2213                 } else if (STps->eof == ST_EOD_1) {
2214                         STps->eof = ST_EOD_2;
2215                         STps->drv_block = 0;
2216                         if (STps->drv_file >= 0)
2217                                 STps->drv_file++;
2218                 } else if (STps->eof == ST_EOD_2)
2219                         STps->eof = ST_EOD;
2220         } else if (STps->eof == ST_FM)
2221                 STps->eof = ST_NOEOF;
2222         retval = total;
2223
2224  out:
2225         if (SRpnt != NULL) {
2226                 st_release_request(SRpnt);
2227                 SRpnt = NULL;
2228         }
2229         if (do_dio) {
2230                 release_buffering(STp, 1);
2231                 STbp->buffer_bytes = 0;
2232         }
2233         mutex_unlock(&STp->lock);
2234
2235         return retval;
2236 }
2237 \f
2238
2239
2240 DEB(
2241 /* Set the driver options */
2242 static void st_log_options(struct scsi_tape * STp, struct st_modedef * STm)
2243 {
2244         if (debugging) {
2245                 st_printk(KERN_INFO, STp,
2246                           "Mode %d options: buffer writes: %d, "
2247                           "async writes: %d, read ahead: %d\n",
2248                           STp->current_mode, STm->do_buffer_writes,
2249                           STm->do_async_writes, STm->do_read_ahead);
2250                 st_printk(KERN_INFO, STp,
2251                           "    can bsr: %d, two FMs: %d, "
2252                           "fast mteom: %d, auto lock: %d,\n",
2253                           STp->can_bsr, STp->two_fm, STp->fast_mteom,
2254                           STp->do_auto_lock);
2255                 st_printk(KERN_INFO, STp,
2256                           "    defs for wr: %d, no block limits: %d, "
2257                           "partitions: %d, s2 log: %d\n",
2258                           STm->defaults_for_writes, STp->omit_blklims,
2259                           STp->can_partitions, STp->scsi2_logical);
2260                 st_printk(KERN_INFO, STp,
2261                           "    sysv: %d nowait: %d sili: %d "
2262                           "nowait_filemark: %d\n",
2263                           STm->sysv, STp->immediate, STp->sili,
2264                           STp->immediate_filemark);
2265                 st_printk(KERN_INFO, STp, "    debugging: %d\n", debugging);
2266         }
2267 }
2268         )
2269
2270
2271 static int st_set_options(struct scsi_tape *STp, long options)
2272 {
2273         int value;
2274         long code;
2275         struct st_modedef *STm;
2276         struct cdev *cd0, *cd1;
2277         struct device *d0, *d1;
2278
2279         STm = &(STp->modes[STp->current_mode]);
2280         if (!STm->defined) {
2281                 cd0 = STm->cdevs[0];
2282                 cd1 = STm->cdevs[1];
2283                 d0  = STm->devs[0];
2284                 d1  = STm->devs[1];
2285                 memcpy(STm, &(STp->modes[0]), sizeof(struct st_modedef));
2286                 STm->cdevs[0] = cd0;
2287                 STm->cdevs[1] = cd1;
2288                 STm->devs[0]  = d0;
2289                 STm->devs[1]  = d1;
2290                 modes_defined = 1;
2291                 DEBC_printk(STp, "Initialized mode %d definition from mode 0\n",
2292                             STp->current_mode);
2293         }
2294
2295         code = options & MT_ST_OPTIONS;
2296         if (code == MT_ST_BOOLEANS) {
2297                 STm->do_buffer_writes = (options & MT_ST_BUFFER_WRITES) != 0;
2298                 STm->do_async_writes = (options & MT_ST_ASYNC_WRITES) != 0;
2299                 STm->defaults_for_writes = (options & MT_ST_DEF_WRITES) != 0;
2300                 STm->do_read_ahead = (options & MT_ST_READ_AHEAD) != 0;
2301                 STp->two_fm = (options & MT_ST_TWO_FM) != 0;
2302                 STp->fast_mteom = (options & MT_ST_FAST_MTEOM) != 0;
2303                 STp->do_auto_lock = (options & MT_ST_AUTO_LOCK) != 0;
2304                 STp->can_bsr = (options & MT_ST_CAN_BSR) != 0;
2305                 STp->omit_blklims = (options & MT_ST_NO_BLKLIMS) != 0;
2306                 if ((STp->device)->scsi_level >= SCSI_2)
2307                         STp->can_partitions = (options & MT_ST_CAN_PARTITIONS) != 0;
2308                 STp->scsi2_logical = (options & MT_ST_SCSI2LOGICAL) != 0;
2309                 STp->immediate = (options & MT_ST_NOWAIT) != 0;
2310                 STp->immediate_filemark = (options & MT_ST_NOWAIT_EOF) != 0;
2311                 STm->sysv = (options & MT_ST_SYSV) != 0;
2312                 STp->sili = (options & MT_ST_SILI) != 0;
2313                 DEB( debugging = (options & MT_ST_DEBUGGING) != 0;
2314                      st_log_options(STp, STm); )
2315         } else if (code == MT_ST_SETBOOLEANS || code == MT_ST_CLEARBOOLEANS) {
2316                 value = (code == MT_ST_SETBOOLEANS);
2317                 if ((options & MT_ST_BUFFER_WRITES) != 0)
2318                         STm->do_buffer_writes = value;
2319                 if ((options & MT_ST_ASYNC_WRITES) != 0)
2320                         STm->do_async_writes = value;
2321                 if ((options & MT_ST_DEF_WRITES) != 0)
2322                         STm->defaults_for_writes = value;
2323                 if ((options & MT_ST_READ_AHEAD) != 0)
2324                         STm->do_read_ahead = value;
2325                 if ((options & MT_ST_TWO_FM) != 0)
2326                         STp->two_fm = value;
2327                 if ((options & MT_ST_FAST_MTEOM) != 0)
2328                         STp->fast_mteom = value;
2329                 if ((options & MT_ST_AUTO_LOCK) != 0)
2330                         STp->do_auto_lock = value;
2331                 if ((options & MT_ST_CAN_BSR) != 0)
2332                         STp->can_bsr = value;
2333                 if ((options & MT_ST_NO_BLKLIMS) != 0)
2334                         STp->omit_blklims = value;
2335                 if ((STp->device)->scsi_level >= SCSI_2 &&
2336                     (options & MT_ST_CAN_PARTITIONS) != 0)
2337                         STp->can_partitions = value;
2338                 if ((options & MT_ST_SCSI2LOGICAL) != 0)
2339                         STp->scsi2_logical = value;
2340                 if ((options & MT_ST_NOWAIT) != 0)
2341                         STp->immediate = value;
2342                 if ((options & MT_ST_NOWAIT_EOF) != 0)
2343                         STp->immediate_filemark = value;
2344                 if ((options & MT_ST_SYSV) != 0)
2345                         STm->sysv = value;
2346                 if ((options & MT_ST_SILI) != 0)
2347                         STp->sili = value;
2348                 DEB(
2349                 if ((options & MT_ST_DEBUGGING) != 0)
2350                         debugging = value;
2351                         st_log_options(STp, STm); )
2352         } else if (code == MT_ST_WRITE_THRESHOLD) {
2353                 /* Retained for compatibility */
2354         } else if (code == MT_ST_DEF_BLKSIZE) {
2355                 value = (options & ~MT_ST_OPTIONS);
2356                 if (value == ~MT_ST_OPTIONS) {
2357                         STm->default_blksize = (-1);
2358                         DEBC_printk(STp, "Default block size disabled.\n");
2359                 } else {
2360                         STm->default_blksize = value;
2361                         DEBC_printk(STp,"Default block size set to "
2362                                     "%d bytes.\n", STm->default_blksize);
2363                         if (STp->ready == ST_READY) {
2364                                 STp->blksize_changed = 0;
2365                                 set_mode_densblk(STp, STm);
2366                         }
2367                 }
2368         } else if (code == MT_ST_TIMEOUTS) {
2369                 value = (options & ~MT_ST_OPTIONS);
2370                 if ((value & MT_ST_SET_LONG_TIMEOUT) != 0) {
2371                         STp->long_timeout = (value & ~MT_ST_SET_LONG_TIMEOUT) * HZ;
2372                         DEBC_printk(STp, "Long timeout set to %d seconds.\n",
2373                                     (value & ~MT_ST_SET_LONG_TIMEOUT));
2374                 } else {
2375                         blk_queue_rq_timeout(STp->device->request_queue,
2376                                              value * HZ);
2377                         DEBC_printk(STp, "Normal timeout set to %d seconds.\n",
2378                                     value);
2379                 }
2380         } else if (code == MT_ST_SET_CLN) {
2381                 value = (options & ~MT_ST_OPTIONS) & 0xff;
2382                 if (value != 0 &&
2383                         (value < EXTENDED_SENSE_START ||
2384                                 value >= SCSI_SENSE_BUFFERSIZE))
2385                         return (-EINVAL);
2386                 STp->cln_mode = value;
2387                 STp->cln_sense_mask = (options >> 8) & 0xff;
2388                 STp->cln_sense_value = (options >> 16) & 0xff;
2389                 st_printk(KERN_INFO, STp,
2390                           "Cleaning request mode %d, mask %02x, value %02x\n",
2391                           value, STp->cln_sense_mask, STp->cln_sense_value);
2392         } else if (code == MT_ST_DEF_OPTIONS) {
2393                 code = (options & ~MT_ST_CLEAR_DEFAULT);
2394                 value = (options & MT_ST_CLEAR_DEFAULT);
2395                 if (code == MT_ST_DEF_DENSITY) {
2396                         if (value == MT_ST_CLEAR_DEFAULT) {
2397                                 STm->default_density = (-1);
2398                                 DEBC_printk(STp,
2399                                             "Density default disabled.\n");
2400                         } else {
2401                                 STm->default_density = value & 0xff;
2402                                 DEBC_printk(STp, "Density default set to %x\n",
2403                                             STm->default_density);
2404                                 if (STp->ready == ST_READY) {
2405                                         STp->density_changed = 0;
2406                                         set_mode_densblk(STp, STm);
2407                                 }
2408                         }
2409                 } else if (code == MT_ST_DEF_DRVBUFFER) {
2410                         if (value == MT_ST_CLEAR_DEFAULT) {
2411                                 STp->default_drvbuffer = 0xff;
2412                                 DEBC_printk(STp,
2413                                             "Drive buffer default disabled.\n");
2414                         } else {
2415                                 STp->default_drvbuffer = value & 7;
2416                                 DEBC_printk(STp,
2417                                             "Drive buffer default set to %x\n",
2418                                             STp->default_drvbuffer);
2419                                 if (STp->ready == ST_READY)
2420                                         st_int_ioctl(STp, MTSETDRVBUFFER, STp->default_drvbuffer);
2421                         }
2422                 } else if (code == MT_ST_DEF_COMPRESSION) {
2423                         if (value == MT_ST_CLEAR_DEFAULT) {
2424                                 STm->default_compression = ST_DONT_TOUCH;
2425                                 DEBC_printk(STp,
2426                                             "Compression default disabled.\n");
2427                         } else {
2428                                 if ((value & 0xff00) != 0) {
2429                                         STp->c_algo = (value & 0xff00) >> 8;
2430                                         DEBC_printk(STp, "Compression "
2431                                                     "algorithm set to 0x%x.\n",
2432                                                     STp->c_algo);
2433                                 }
2434                                 if ((value & 0xff) != 0xff) {
2435                                         STm->default_compression = (value & 1 ? ST_YES : ST_NO);
2436                                         DEBC_printk(STp, "Compression default "
2437                                                     "set to %x\n",
2438                                                     (value & 1));
2439                                         if (STp->ready == ST_READY) {
2440                                                 STp->compression_changed = 0;
2441                                                 st_compression(STp, (STm->default_compression == ST_YES));
2442                                         }
2443                                 }
2444                         }
2445                 }
2446         } else
2447                 return (-EIO);
2448
2449         return 0;
2450 }
2451 \f
2452 #define MODE_HEADER_LENGTH  4
2453
2454 /* Mode header and page byte offsets */
2455 #define MH_OFF_DATA_LENGTH     0
2456 #define MH_OFF_MEDIUM_TYPE     1
2457 #define MH_OFF_DEV_SPECIFIC    2
2458 #define MH_OFF_BDESCS_LENGTH   3
2459 #define MP_OFF_PAGE_NBR        0
2460 #define MP_OFF_PAGE_LENGTH     1
2461
2462 /* Mode header and page bit masks */
2463 #define MH_BIT_WP              0x80
2464 #define MP_MSK_PAGE_NBR        0x3f
2465
2466 /* Don't return block descriptors */
2467 #define MODE_SENSE_OMIT_BDESCS 0x08
2468
2469 #define MODE_SELECT_PAGE_FORMAT 0x10
2470
2471 /* Read a mode page into the tape buffer. The block descriptors are included
2472    if incl_block_descs is true. The page control is ored to the page number
2473    parameter, if necessary. */
2474 static int read_mode_page(struct scsi_tape *STp, int page, int omit_block_descs)
2475 {
2476         unsigned char cmd[MAX_COMMAND_SIZE];
2477         struct st_request *SRpnt;
2478
2479         memset(cmd, 0, MAX_COMMAND_SIZE);
2480         cmd[0] = MODE_SENSE;
2481         if (omit_block_descs)
2482                 cmd[1] = MODE_SENSE_OMIT_BDESCS;
2483         cmd[2] = page;
2484         cmd[4] = 255;
2485
2486         SRpnt = st_do_scsi(NULL, STp, cmd, cmd[4], DMA_FROM_DEVICE,
2487                            STp->device->request_queue->rq_timeout, 0, 1);
2488         if (SRpnt == NULL)
2489                 return (STp->buffer)->syscall_result;
2490
2491         st_release_request(SRpnt);
2492
2493         return STp->buffer->syscall_result;
2494 }
2495
2496
2497 /* Send the mode page in the tape buffer to the drive. Assumes that the mode data
2498    in the buffer is correctly formatted. The long timeout is used if slow is non-zero. */
2499 static int write_mode_page(struct scsi_tape *STp, int page, int slow)
2500 {
2501         int pgo;
2502         unsigned char cmd[MAX_COMMAND_SIZE];
2503         struct st_request *SRpnt;
2504         int timeout;
2505
2506         memset(cmd, 0, MAX_COMMAND_SIZE);
2507         cmd[0] = MODE_SELECT;
2508         cmd[1] = MODE_SELECT_PAGE_FORMAT;
2509         pgo = MODE_HEADER_LENGTH + (STp->buffer)->b_data[MH_OFF_BDESCS_LENGTH];
2510         cmd[4] = pgo + (STp->buffer)->b_data[pgo + MP_OFF_PAGE_LENGTH] + 2;
2511
2512         /* Clear reserved fields */
2513         (STp->buffer)->b_data[MH_OFF_DATA_LENGTH] = 0;
2514         (STp->buffer)->b_data[MH_OFF_MEDIUM_TYPE] = 0;
2515         (STp->buffer)->b_data[MH_OFF_DEV_SPECIFIC] &= ~MH_BIT_WP;
2516         (STp->buffer)->b_data[pgo + MP_OFF_PAGE_NBR] &= MP_MSK_PAGE_NBR;
2517
2518         timeout = slow ?
2519                 STp->long_timeout : STp->device->request_queue->rq_timeout;
2520         SRpnt = st_do_scsi(NULL, STp, cmd, cmd[4], DMA_TO_DEVICE,
2521                            timeout, 0, 1);
2522         if (SRpnt == NULL)
2523                 return (STp->buffer)->syscall_result;
2524
2525         st_release_request(SRpnt);
2526
2527         return STp->buffer->syscall_result;
2528 }
2529
2530
2531 #define COMPRESSION_PAGE        0x0f
2532 #define COMPRESSION_PAGE_LENGTH 16
2533
2534 #define CP_OFF_DCE_DCC          2
2535 #define CP_OFF_C_ALGO           7
2536
2537 #define DCE_MASK  0x80
2538 #define DCC_MASK  0x40
2539 #define RED_MASK  0x60
2540
2541
2542 /* Control the compression with mode page 15. Algorithm not changed if zero.
2543
2544    The block descriptors are read and written because Sony SDT-7000 does not
2545    work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
2546    Including block descriptors should not cause any harm to other drives. */
2547
2548 static int st_compression(struct scsi_tape * STp, int state)
2549 {
2550         int retval;
2551         int mpoffs;  /* Offset to mode page start */
2552         unsigned char *b_data = (STp->buffer)->b_data;
2553
2554         if (STp->ready != ST_READY)
2555                 return (-EIO);
2556
2557         /* Read the current page contents */
2558         retval = read_mode_page(STp, COMPRESSION_PAGE, 0);
2559         if (retval) {
2560                 DEBC_printk(STp, "Compression mode page not supported.\n");
2561                 return (-EIO);
2562         }
2563
2564         mpoffs = MODE_HEADER_LENGTH + b_data[MH_OFF_BDESCS_LENGTH];
2565         DEBC_printk(STp, "Compression state is %d.\n",
2566                     (b_data[mpoffs + CP_OFF_DCE_DCC] & DCE_MASK ? 1 : 0));
2567
2568         /* Check if compression can be changed */
2569         if ((b_data[mpoffs + CP_OFF_DCE_DCC] & DCC_MASK) == 0) {
2570                 DEBC_printk(STp, "Compression not supported.\n");
2571                 return (-EIO);
2572         }
2573
2574         /* Do the change */
2575         if (state) {
2576                 b_data[mpoffs + CP_OFF_DCE_DCC] |= DCE_MASK;
2577                 if (STp->c_algo != 0)
2578                         b_data[mpoffs + CP_OFF_C_ALGO] = STp->c_algo;
2579         }
2580         else {
2581                 b_data[mpoffs + CP_OFF_DCE_DCC] &= ~DCE_MASK;
2582                 if (STp->c_algo != 0)
2583                         b_data[mpoffs + CP_OFF_C_ALGO] = 0; /* no compression */
2584         }
2585
2586         retval = write_mode_page(STp, COMPRESSION_PAGE, 0);
2587         if (retval) {
2588                 DEBC_printk(STp, "Compression change failed.\n");
2589                 return (-EIO);
2590         }
2591         DEBC_printk(STp, "Compression state changed to %d.\n", state);
2592
2593         STp->compression_changed = 1;
2594         return 0;
2595 }
2596
2597
2598 /* Process the load and unload commands (does unload if the load code is zero) */
2599 static int do_load_unload(struct scsi_tape *STp, struct file *filp, int load_code)
2600 {
2601         int retval = (-EIO), timeout;
2602         unsigned char cmd[MAX_COMMAND_SIZE];
2603         struct st_partstat *STps;
2604         struct st_request *SRpnt;
2605
2606         if (STp->ready != ST_READY && !load_code) {
2607                 if (STp->ready == ST_NO_TAPE)
2608                         return (-ENOMEDIUM);
2609                 else
2610                         return (-EIO);
2611         }
2612
2613         memset(cmd, 0, MAX_COMMAND_SIZE);
2614         cmd[0] = START_STOP;
2615         if (load_code)
2616                 cmd[4] |= 1;
2617         /*
2618          * If arg >= 1 && arg <= 6 Enhanced load/unload in HP C1553A
2619          */
2620         if (load_code >= 1 + MT_ST_HPLOADER_OFFSET
2621             && load_code <= 6 + MT_ST_HPLOADER_OFFSET) {
2622                 DEBC_printk(STp, " Enhanced %sload slot %2d.\n",
2623                             (cmd[4]) ? "" : "un",
2624                             load_code - MT_ST_HPLOADER_OFFSET);
2625                 cmd[3] = load_code - MT_ST_HPLOADER_OFFSET; /* MediaID field of C1553A */
2626         }
2627         if (STp->immediate) {
2628                 cmd[1] = 1;     /* Don't wait for completion */
2629                 timeout = STp->device->request_queue->rq_timeout;
2630         }
2631         else
2632                 timeout = STp->long_timeout;
2633
2634         DEBC(
2635                 if (!load_code)
2636                         st_printk(ST_DEB_MSG, STp, "Unloading tape.\n");
2637                 else
2638                         st_printk(ST_DEB_MSG, STp, "Loading tape.\n");
2639                 );
2640
2641         SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
2642                            timeout, MAX_RETRIES, 1);
2643         if (!SRpnt)
2644                 return (STp->buffer)->syscall_result;
2645
2646         retval = (STp->buffer)->syscall_result;
2647         st_release_request(SRpnt);
2648
2649         if (!retval) {  /* SCSI command successful */
2650
2651                 if (!load_code) {
2652                         STp->rew_at_close = 0;
2653                         STp->ready = ST_NO_TAPE;
2654                 }
2655                 else {
2656                         STp->rew_at_close = STp->autorew_dev;
2657                         retval = check_tape(STp, filp);
2658                         if (retval > 0)
2659                                 retval = 0;
2660                 }
2661         }
2662         else {
2663                 STps = &(STp->ps[STp->partition]);
2664                 STps->drv_file = STps->drv_block = (-1);
2665         }
2666
2667         return retval;
2668 }
2669 \f
2670 #if DEBUG
2671 #define ST_DEB_FORWARD  0
2672 #define ST_DEB_BACKWARD 1
2673 static void deb_space_print(struct scsi_tape *STp, int direction, char *units, unsigned char *cmd)
2674 {
2675         s32 sc;
2676
2677         if (!debugging)
2678                 return;
2679
2680         sc = cmd[2] & 0x80 ? 0xff000000 : 0;
2681         sc |= (cmd[2] << 16) | (cmd[3] << 8) | cmd[4];
2682         if (direction)
2683                 sc = -sc;
2684         st_printk(ST_DEB_MSG, STp, "Spacing tape %s over %d %s.\n",
2685                   direction ? "backward" : "forward", sc, units);
2686 }
2687 #else
2688 #define ST_DEB_FORWARD  0
2689 #define ST_DEB_BACKWARD 1
2690 static void deb_space_print(struct scsi_tape *STp, int direction, char *units, unsigned char *cmd) {}
2691 #endif
2692
2693
2694 /* Internal ioctl function */
2695 static int st_int_ioctl(struct scsi_tape *STp, unsigned int cmd_in, unsigned long arg)
2696 {
2697         int timeout;
2698         long ltmp;
2699         int ioctl_result;
2700         int chg_eof = 1;
2701         unsigned char cmd[MAX_COMMAND_SIZE];
2702         struct st_request *SRpnt;
2703         struct st_partstat *STps;
2704         int fileno, blkno, at_sm, undone;
2705         int datalen = 0, direction = DMA_NONE;
2706
2707         WARN_ON(STp->buffer->do_dio != 0);
2708         if (STp->ready != ST_READY) {
2709                 if (STp->ready == ST_NO_TAPE)
2710                         return (-ENOMEDIUM);
2711                 else
2712                         return (-EIO);
2713         }
2714         timeout = STp->long_timeout;
2715         STps = &(STp->ps[STp->partition]);
2716         fileno = STps->drv_file;
2717         blkno = STps->drv_block;
2718         at_sm = STps->at_sm;
2719
2720         memset(cmd, 0, MAX_COMMAND_SIZE);
2721         switch (cmd_in) {
2722         case MTFSFM:
2723                 chg_eof = 0;    /* Changed from the FSF after this */
2724         case MTFSF:
2725                 cmd[0] = SPACE;
2726                 cmd[1] = 0x01;  /* Space FileMarks */
2727                 cmd[2] = (arg >> 16);
2728                 cmd[3] = (arg >> 8);
2729                 cmd[4] = arg;
2730                 deb_space_print(STp, ST_DEB_FORWARD, "filemarks", cmd);
2731                 if (fileno >= 0)
2732                         fileno += arg;
2733                 blkno = 0;
2734                 at_sm &= (arg == 0);
2735                 break;
2736         case MTBSFM:
2737                 chg_eof = 0;    /* Changed from the FSF after this */
2738         case MTBSF:
2739                 cmd[0] = SPACE;
2740                 cmd[1] = 0x01;  /* Space FileMarks */
2741                 ltmp = (-arg);
2742                 cmd[2] = (ltmp >> 16);
2743                 cmd[3] = (ltmp >> 8);
2744                 cmd[4] = ltmp;
2745                 deb_space_print(STp, ST_DEB_BACKWARD, "filemarks", cmd);
2746                 if (fileno >= 0)
2747                         fileno -= arg;
2748                 blkno = (-1);   /* We can't know the block number */
2749                 at_sm &= (arg == 0);
2750                 break;
2751         case MTFSR:
2752                 cmd[0] = SPACE;
2753                 cmd[1] = 0x00;  /* Space Blocks */
2754                 cmd[2] = (arg >> 16);
2755                 cmd[3] = (arg >> 8);
2756                 cmd[4] = arg;
2757                 deb_space_print(STp, ST_DEB_FORWARD, "blocks", cmd);
2758                 if (blkno >= 0)
2759                         blkno += arg;
2760                 at_sm &= (arg == 0);
2761                 break;
2762         case MTBSR:
2763                 cmd[0] = SPACE;
2764                 cmd[1] = 0x00;  /* Space Blocks */
2765                 ltmp = (-arg);
2766                 cmd[2] = (ltmp >> 16);
2767                 cmd[3] = (ltmp >> 8);
2768                 cmd[4] = ltmp;
2769                 deb_space_print(STp, ST_DEB_BACKWARD, "blocks", cmd);
2770                 if (blkno >= 0)
2771                         blkno -= arg;
2772                 at_sm &= (arg == 0);
2773                 break;
2774         case MTFSS:
2775                 cmd[0] = SPACE;
2776                 cmd[1] = 0x04;  /* Space Setmarks */
2777                 cmd[2] = (arg >> 16);
2778                 cmd[3] = (arg >> 8);
2779                 cmd[4] = arg;
2780                 deb_space_print(STp, ST_DEB_FORWARD, "setmarks", cmd);
2781                 if (arg != 0) {
2782                         blkno = fileno = (-1);
2783                         at_sm = 1;
2784                 }
2785                 break;
2786         case MTBSS:
2787                 cmd[0] = SPACE;
2788                 cmd[1] = 0x04;  /* Space Setmarks */
2789                 ltmp = (-arg);
2790                 cmd[2] = (ltmp >> 16);
2791                 cmd[3] = (ltmp >> 8);
2792                 cmd[4] = ltmp;
2793                 deb_space_print(STp, ST_DEB_BACKWARD, "setmarks", cmd);
2794                 if (arg != 0) {
2795                         blkno = fileno = (-1);
2796                         at_sm = 1;
2797                 }
2798                 break;
2799         case MTWEOF:
2800         case MTWEOFI:
2801         case MTWSM:
2802                 if (STp->write_prot)
2803                         return (-EACCES);
2804                 cmd[0] = WRITE_FILEMARKS;
2805                 if (cmd_in == MTWSM)
2806                         cmd[1] = 2;
2807                 if (cmd_in == MTWEOFI ||
2808                     (cmd_in == MTWEOF && STp->immediate_filemark))
2809                         cmd[1] |= 1;
2810                 cmd[2] = (arg >> 16);
2811                 cmd[3] = (arg >> 8);
2812                 cmd[4] = arg;
2813                 timeout = STp->device->request_queue->rq_timeout;
2814                 DEBC(
2815                         if (cmd_in != MTWSM)
2816                                 st_printk(ST_DEB_MSG, STp,
2817                                           "Writing %d filemarks.\n",
2818                                           cmd[2] * 65536 +
2819                                           cmd[3] * 256 +
2820                                           cmd[4]);
2821                         else
2822                                 st_printk(ST_DEB_MSG, STp,
2823                                           "Writing %d setmarks.\n",
2824                                           cmd[2] * 65536 +
2825                                           cmd[3] * 256 +
2826                                           cmd[4]);
2827                 )
2828                 if (fileno >= 0)
2829                         fileno += arg;
2830                 blkno = 0;
2831                 at_sm = (cmd_in == MTWSM);
2832                 break;
2833         case MTREW:
2834                 cmd[0] = REZERO_UNIT;
2835                 if (STp->immediate) {
2836                         cmd[1] = 1;     /* Don't wait for completion */
2837                         timeout = STp->device->request_queue->rq_timeout;
2838                 }
2839                 DEBC_printk(STp, "Rewinding tape.\n");
2840                 fileno = blkno = at_sm = 0;
2841                 break;
2842         case MTNOP:
2843                 DEBC_printk(STp, "No op on tape.\n");
2844                 return 0;       /* Should do something ? */
2845                 break;
2846         case MTRETEN:
2847                 cmd[0] = START_STOP;
2848                 if (STp->immediate) {
2849                         cmd[1] = 1;     /* Don't wait for completion */
2850                         timeout = STp->device->request_queue->rq_timeout;
2851                 }
2852                 cmd[4] = 3;
2853                 DEBC_printk(STp, "Retensioning tape.\n");
2854                 fileno = blkno = at_sm = 0;
2855                 break;
2856         case MTEOM:
2857                 if (!STp->fast_mteom) {
2858                         /* space to the end of tape */
2859                         ioctl_result = st_int_ioctl(STp, MTFSF, 0x7fffff);
2860                         fileno = STps->drv_file;
2861                         if (STps->eof >= ST_EOD_1)
2862                                 return 0;
2863                         /* The next lines would hide the number of spaced FileMarks
2864                            That's why I inserted the previous lines. I had no luck
2865                            with detecting EOM with FSF, so we go now to EOM.
2866                            Joerg Weule */
2867                 } else
2868                         fileno = (-1);
2869                 cmd[0] = SPACE;
2870                 cmd[1] = 3;
2871                 DEBC_printk(STp, "Spacing to end of recorded medium.\n");
2872                 blkno = -1;
2873                 at_sm = 0;
2874                 break;
2875         case MTERASE:
2876                 if (STp->write_prot)
2877                         return (-EACCES);
2878                 cmd[0] = ERASE;
2879                 cmd[1] = (arg ? 1 : 0); /* Long erase with non-zero argument */
2880                 if (STp->immediate) {
2881                         cmd[1] |= 2;    /* Don't wait for completion */
2882                         timeout = STp->device->request_queue->rq_timeout;
2883                 }
2884                 else
2885                         timeout = STp->long_timeout * 8;
2886
2887                 DEBC_printk(STp, "Erasing tape.\n");
2888                 fileno = blkno = at_sm = 0;
2889                 break;
2890         case MTSETBLK:          /* Set block length */
2891         case MTSETDENSITY:      /* Set tape density */
2892         case MTSETDRVBUFFER:    /* Set drive buffering */
2893         case SET_DENS_AND_BLK:  /* Set density and block size */
2894                 chg_eof = 0;
2895                 if (STp->dirty || (STp->buffer)->buffer_bytes != 0)
2896                         return (-EIO);  /* Not allowed if data in buffer */
2897                 if ((cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) &&
2898                     (arg & MT_ST_BLKSIZE_MASK) != 0 &&
2899                     STp->max_block > 0 &&
2900                     ((arg & MT_ST_BLKSIZE_MASK) < STp->min_block ||
2901                      (arg & MT_ST_BLKSIZE_MASK) > STp->max_block)) {
2902                         st_printk(KERN_WARNING, STp, "Illegal block size.\n");
2903                         return (-EINVAL);
2904                 }
2905                 cmd[0] = MODE_SELECT;
2906                 if ((STp->use_pf & USE_PF))
2907                         cmd[1] = MODE_SELECT_PAGE_FORMAT;
2908                 cmd[4] = datalen = 12;
2909                 direction = DMA_TO_DEVICE;
2910
2911                 memset((STp->buffer)->b_data, 0, 12);
2912                 if (cmd_in == MTSETDRVBUFFER)
2913                         (STp->buffer)->b_data[2] = (arg & 7) << 4;
2914                 else
2915                         (STp->buffer)->b_data[2] =
2916                             STp->drv_buffer << 4;
2917                 (STp->buffer)->b_data[3] = 8;   /* block descriptor length */
2918                 if (cmd_in == MTSETDENSITY) {
2919                         (STp->buffer)->b_data[4] = arg;
2920                         STp->density_changed = 1;       /* At least we tried ;-) */
2921                 } else if (cmd_in == SET_DENS_AND_BLK)
2922                         (STp->buffer)->b_data[4] = arg >> 24;
2923                 else
2924                         (STp->buffer)->b_data[4] = STp->density;
2925                 if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2926                         ltmp = arg & MT_ST_BLKSIZE_MASK;
2927                         if (cmd_in == MTSETBLK)
2928                                 STp->blksize_changed = 1; /* At least we tried ;-) */
2929                 } else
2930                         ltmp = STp->block_size;
2931                 (STp->buffer)->b_data[9] = (ltmp >> 16);
2932                 (STp->buffer)->b_data[10] = (ltmp >> 8);
2933                 (STp->buffer)->b_data[11] = ltmp;
2934                 timeout = STp->device->request_queue->rq_timeout;
2935                 DEBC(
2936                         if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK)
2937                                 st_printk(ST_DEB_MSG, STp,
2938                                           "Setting block size to %d bytes.\n",
2939                                           (STp->buffer)->b_data[9] * 65536 +
2940                                           (STp->buffer)->b_data[10] * 256 +
2941                                           (STp->buffer)->b_data[11]);
2942                         if (cmd_in == MTSETDENSITY || cmd_in == SET_DENS_AND_BLK)
2943                                 st_printk(ST_DEB_MSG, STp,
2944                                           "Setting density code to %x.\n",
2945                                           (STp->buffer)->b_data[4]);
2946                         if (cmd_in == MTSETDRVBUFFER)
2947                                 st_printk(ST_DEB_MSG, STp,
2948                                           "Setting drive buffer code to %d.\n",
2949                                           ((STp->buffer)->b_data[2] >> 4) & 7);
2950                 )
2951                 break;
2952         default:
2953                 return (-ENOSYS);
2954         }
2955
2956         SRpnt = st_do_scsi(NULL, STp, cmd, datalen, direction,
2957                            timeout, MAX_RETRIES, 1);
2958         if (!SRpnt)
2959                 return (STp->buffer)->syscall_result;
2960
2961         ioctl_result = (STp->buffer)->syscall_result;
2962
2963         if (!ioctl_result) {    /* SCSI command successful */
2964                 st_release_request(SRpnt);
2965                 SRpnt = NULL;
2966                 STps->drv_block = blkno;
2967                 STps->drv_file = fileno;
2968                 STps->at_sm = at_sm;
2969
2970                 if (cmd_in == MTBSFM)
2971                         ioctl_result = st_int_ioctl(STp, MTFSF, 1);
2972                 else if (cmd_in == MTFSFM)
2973                         ioctl_result = st_int_ioctl(STp, MTBSF, 1);
2974
2975                 if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2976                         STp->block_size = arg & MT_ST_BLKSIZE_MASK;
2977                         if (STp->block_size != 0) {
2978                                 (STp->buffer)->buffer_blocks =
2979                                     (STp->buffer)->buffer_size / STp->block_size;
2980                         }
2981                         (STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
2982                         if (cmd_in == SET_DENS_AND_BLK)
2983                                 STp->density = arg >> MT_ST_DENSITY_SHIFT;
2984                 } else if (cmd_in == MTSETDRVBUFFER)
2985                         STp->drv_buffer = (arg & 7);
2986                 else if (cmd_in == MTSETDENSITY)
2987                         STp->density = arg;
2988
2989                 if (cmd_in == MTEOM)
2990                         STps->eof = ST_EOD;
2991                 else if (cmd_in == MTFSF)
2992                         STps->eof = ST_FM;
2993                 else if (chg_eof)
2994                         STps->eof = ST_NOEOF;
2995
2996                 if (cmd_in == MTWEOF || cmd_in == MTWEOFI)
2997                         STps->rw = ST_IDLE;  /* prevent automatic WEOF at close */
2998         } else { /* SCSI command was not completely successful. Don't return
2999                     from this block without releasing the SCSI command block! */
3000                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
3001
3002                 if (cmdstatp->flags & SENSE_EOM) {
3003                         if (cmd_in != MTBSF && cmd_in != MTBSFM &&
3004                             cmd_in != MTBSR && cmd_in != MTBSS)
3005                                 STps->eof = ST_EOM_OK;
3006                         STps->drv_block = 0;
3007                 }
3008
3009                 if (cmdstatp->remainder_valid)
3010                         undone = (int)cmdstatp->uremainder64;
3011                 else
3012                         undone = 0;
3013
3014                 if ((cmd_in == MTWEOF || cmd_in == MTWEOFI) &&
3015                     cmdstatp->have_sense &&
3016                     (cmdstatp->flags & SENSE_EOM)) {
3017                         if (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
3018                             cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) {
3019                                 ioctl_result = 0;       /* EOF(s) written successfully at EOM */
3020                                 STps->eof = ST_NOEOF;
3021                         } else {  /* Writing EOF(s) failed */
3022                                 if (fileno >= 0)
3023                                         fileno -= undone;
3024                                 if (undone < arg)
3025                                         STps->eof = ST_NOEOF;
3026                         }
3027                         STps->drv_file = fileno;
3028                 } else if ((cmd_in == MTFSF) || (cmd_in == MTFSFM)) {
3029                         if (fileno >= 0)
3030                                 STps->drv_file = fileno - undone;
3031                         else
3032                                 STps->drv_file = fileno;
3033                         STps->drv_block = -1;
3034                         STps->eof = ST_NOEOF;
3035                 } else if ((cmd_in == MTBSF) || (cmd_in == MTBSFM)) {
3036                         if (arg > 0 && undone < 0)  /* Some drives get this wrong */
3037                                 undone = (-undone);
3038                         if (STps->drv_file >= 0)
3039                                 STps->drv_file = fileno + undone;
3040                         STps->drv_block = 0;
3041                         STps->eof = ST_NOEOF;
3042                 } else if (cmd_in == MTFSR) {
3043                         if (cmdstatp->flags & SENSE_FMK) {      /* Hit filemark */
3044                                 if (STps->drv_file >= 0)
3045                                         STps->drv_file++;
3046                                 STps->drv_block = 0;
3047                                 STps->eof = ST_FM;
3048                         } else {
3049                                 if (blkno >= undone)
3050                                         STps->drv_block = blkno - undone;
3051                                 else
3052                                         STps->drv_block = (-1);
3053                                 STps->eof = ST_NOEOF;
3054                         }
3055                 } else if (cmd_in == MTBSR) {
3056                         if (cmdstatp->flags & SENSE_FMK) {      /* Hit filemark */
3057                                 STps->drv_file--;
3058                                 STps->drv_block = (-1);
3059                         } else {
3060                                 if (arg > 0 && undone < 0)  /* Some drives get this wrong */
3061                                         undone = (-undone);
3062                                 if (STps->drv_block >= 0)
3063                                         STps->drv_block = blkno + undone;
3064                         }
3065                         STps->eof = ST_NOEOF;
3066                 } else if (cmd_in == MTEOM) {
3067                         STps->drv_file = (-1);
3068                         STps->drv_block = (-1);
3069                         STps->eof = ST_EOD;
3070                 } else if (cmd_in == MTSETBLK ||
3071                            cmd_in == MTSETDENSITY ||
3072                            cmd_in == MTSETDRVBUFFER ||
3073                            cmd_in == SET_DENS_AND_BLK) {
3074                         if (cmdstatp->sense_hdr.sense_key == ILLEGAL_REQUEST &&
3075                             !(STp->use_pf & PF_TESTED)) {
3076                                 /* Try the other possible state of Page Format if not
3077                                    already tried */
3078                                 STp->use_pf = (STp->use_pf ^ USE_PF) | PF_TESTED;
3079                                 st_release_request(SRpnt);
3080                                 SRpnt = NULL;
3081                                 return st_int_ioctl(STp, cmd_in, arg);
3082                         }
3083                 } else if (chg_eof)
3084                         STps->eof = ST_NOEOF;
3085
3086                 if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
3087                         STps->eof = ST_EOD;
3088
3089                 st_release_request(SRpnt);
3090                 SRpnt = NULL;
3091         }
3092
3093         return ioctl_result;
3094 }
3095 \f
3096
3097 /* Get the tape position. If bt == 2, arg points into a kernel space mt_loc
3098    structure. */
3099
3100 static int get_location(struct scsi_tape *STp, unsigned int *block, int *partition,
3101                         int logical)
3102 {
3103         int result;
3104         unsigned char scmd[MAX_COMMAND_SIZE];
3105         struct st_request *SRpnt;
3106
3107         if (STp->ready != ST_READY)
3108                 return (-EIO);
3109
3110         memset(scmd, 0, MAX_COMMAND_SIZE);
3111         if ((STp->device)->scsi_level < SCSI_2) {
3112                 scmd[0] = QFA_REQUEST_BLOCK;
3113                 scmd[4] = 3;
3114         } else {
3115                 scmd[0] = READ_POSITION;
3116                 if (!logical && !STp->scsi2_logical)
3117                         scmd[1] = 1;
3118         }
3119         SRpnt = st_do_scsi(NULL, STp, scmd, 20, DMA_FROM_DEVICE,
3120                            STp->device->request_queue->rq_timeout,
3121                            MAX_READY_RETRIES, 1);
3122         if (!SRpnt)
3123                 return (STp->buffer)->syscall_result;
3124
3125         if ((STp->buffer)->syscall_result != 0 ||
3126             (STp->device->scsi_level >= SCSI_2 &&
3127              ((STp->buffer)->b_data[0] & 4) != 0)) {
3128                 *block = *partition = 0;
3129                 DEBC_printk(STp, " Can't read tape position.\n");
3130                 result = (-EIO);
3131         } else {
3132                 result = 0;
3133                 if ((STp->device)->scsi_level < SCSI_2) {
3134                         *block = ((STp->buffer)->b_data[0] << 16)
3135                             + ((STp->buffer)->b_data[1] << 8)
3136                             + (STp->buffer)->b_data[2];
3137                         *partition = 0;
3138                 } else {
3139                         *block = ((STp->buffer)->b_data[4] << 24)
3140                             + ((STp->buffer)->b_data[5] << 16)
3141                             + ((STp->buffer)->b_data[6] << 8)
3142                             + (STp->buffer)->b_data[7];
3143                         *partition = (STp->buffer)->b_data[1];
3144                         if (((STp->buffer)->b_data[0] & 0x80) &&
3145                             (STp->buffer)->b_data[1] == 0)      /* BOP of partition 0 */
3146                                 STp->ps[0].drv_block = STp->ps[0].drv_file = 0;
3147                 }
3148                 DEBC_printk(STp, "Got tape pos. blk %d part %d.\n",
3149                             *block, *partition);
3150         }
3151         st_release_request(SRpnt);
3152         SRpnt = NULL;
3153
3154         return result;
3155 }
3156
3157
3158 /* Set the tape block and partition. Negative partition means that only the
3159    block should be set in vendor specific way. */
3160 static int set_location(struct scsi_tape *STp, unsigned int block, int partition,
3161                         int logical)
3162 {
3163         struct st_partstat *STps;
3164         int result, p;
3165         unsigned int blk;
3166         int timeout;
3167         unsigned char scmd[MAX_COMMAND_SIZE];
3168         struct st_request *SRpnt;
3169
3170         if (STp->ready != ST_READY)
3171                 return (-EIO);
3172         timeout = STp->long_timeout;
3173         STps = &(STp->ps[STp->partition]);
3174
3175         DEBC_printk(STp, "Setting block to %d and partition to %d.\n",
3176                     block, partition);
3177         DEB(if (partition < 0)
3178                 return (-EIO); )
3179
3180         /* Update the location at the partition we are leaving */
3181         if ((!STp->can_partitions && partition != 0) ||
3182             partition >= ST_NBR_PARTITIONS)
3183                 return (-EINVAL);
3184         if (partition != STp->partition) {
3185                 if (get_location(STp, &blk, &p, 1))
3186                         STps->last_block_valid = 0;
3187                 else {
3188                         STps->last_block_valid = 1;
3189                         STps->last_block_visited = blk;
3190                         DEBC_printk(STp, "Visited block %d for "
3191                                     "partition %d saved.\n",
3192                                     blk, STp->partition);
3193                 }
3194         }
3195
3196         memset(scmd, 0, MAX_COMMAND_SIZE);
3197         if ((STp->device)->scsi_level < SCSI_2) {
3198                 scmd[0] = QFA_SEEK_BLOCK;
3199                 scmd[2] = (block >> 16);
3200                 scmd[3] = (block >> 8);
3201                 scmd[4] = block;
3202                 scmd[5] = 0;
3203         } else {
3204                 scmd[0] = SEEK_10;
3205                 scmd[3] = (block >> 24);
3206                 scmd[4] = (block >> 16);
3207                 scmd[5] = (block >> 8);
3208                 scmd[6] = block;
3209                 if (!logical && !STp->scsi2_logical)
3210                         scmd[1] = 4;
3211                 if (STp->partition != partition) {
3212                         scmd[1] |= 2;
3213                         scmd[8] = partition;
3214                         DEBC_printk(STp, "Trying to change partition "
3215                                     "from %d to %d\n", STp->partition,
3216                                     partition);
3217                 }
3218         }
3219         if (STp->immediate) {
3220                 scmd[1] |= 1;           /* Don't wait for completion */
3221                 timeout = STp->device->request_queue->rq_timeout;
3222         }
3223
3224         SRpnt = st_do_scsi(NULL, STp, scmd, 0, DMA_NONE,
3225                            timeout, MAX_READY_RETRIES, 1);
3226         if (!SRpnt)
3227                 return (STp->buffer)->syscall_result;
3228
3229         STps->drv_block = STps->drv_file = (-1);
3230         STps->eof = ST_NOEOF;
3231         if ((STp->buffer)->syscall_result != 0) {
3232                 result = (-EIO);
3233                 if (STp->can_partitions &&
3234                     (STp->device)->scsi_level >= SCSI_2 &&
3235                     (p = find_partition(STp)) >= 0)
3236                         STp->partition = p;
3237         } else {
3238                 if (STp->can_partitions) {
3239                         STp->partition = partition;
3240                         STps = &(STp->ps[partition]);
3241                         if (!STps->last_block_valid ||
3242                             STps->last_block_visited != block) {
3243                                 STps->at_sm = 0;
3244                                 STps->rw = ST_IDLE;
3245                         }
3246                 } else
3247                         STps->at_sm = 0;
3248                 if (block == 0)
3249                         STps->drv_block = STps->drv_file = 0;
3250                 result = 0;
3251         }
3252
3253         st_release_request(SRpnt);
3254         SRpnt = NULL;
3255
3256         return result;
3257 }
3258
3259
3260 /* Find the current partition number for the drive status. Called from open and
3261    returns either partition number of negative error code. */
3262 static int find_partition(struct scsi_tape *STp)
3263 {
3264         int i, partition;
3265         unsigned int block;
3266
3267         if ((i = get_location(STp, &block, &partition, 1)) < 0)
3268                 return i;
3269         if (partition >= ST_NBR_PARTITIONS)
3270                 return (-EIO);
3271         return partition;
3272 }
3273
3274
3275 /* Change the partition if necessary */
3276 static int switch_partition(struct scsi_tape *STp)
3277 {
3278         struct st_partstat *STps;
3279
3280         if (STp->partition == STp->new_partition)
3281                 return 0;
3282         STps = &(STp->ps[STp->new_partition]);
3283         if (!STps->last_block_valid)
3284                 STps->last_block_visited = 0;
3285         return set_location(STp, STps->last_block_visited, STp->new_partition, 1);
3286 }
3287 \f
3288 /* Functions for reading and writing the medium partition mode page. */
3289
3290 #define PART_PAGE   0x11
3291 #define PART_PAGE_FIXED_LENGTH 8
3292
3293 #define PP_OFF_MAX_ADD_PARTS   2
3294 #define PP_OFF_NBR_ADD_PARTS   3
3295 #define PP_OFF_FLAGS           4
3296 #define PP_OFF_PART_UNITS      6
3297 #define PP_OFF_RESERVED        7
3298
3299 #define PP_BIT_IDP             0x20
3300 #define PP_BIT_FDP             0x80
3301 #define PP_MSK_PSUM_MB         0x10
3302 #define PP_MSK_PSUM_UNITS      0x18
3303 #define PP_MSK_POFM            0x04
3304
3305 /* Get the number of partitions on the tape. As a side effect reads the
3306    mode page into the tape buffer. */
3307 static int nbr_partitions(struct scsi_tape *STp)
3308 {
3309         int result;
3310
3311         if (STp->ready != ST_READY)
3312                 return (-EIO);
3313
3314         result = read_mode_page(STp, PART_PAGE, 1);
3315
3316         if (result) {
3317                 DEBC_printk(STp, "Can't read medium partition page.\n");
3318                 result = (-EIO);
3319         } else {
3320                 result = (STp->buffer)->b_data[MODE_HEADER_LENGTH +
3321                                               PP_OFF_NBR_ADD_PARTS] + 1;
3322                 DEBC_printk(STp, "Number of partitions %d.\n", result);
3323         }
3324
3325         return result;
3326 }
3327
3328
3329 static int format_medium(struct scsi_tape *STp, int format)
3330 {
3331         int result = 0;
3332         int timeout = STp->long_timeout;
3333         unsigned char scmd[MAX_COMMAND_SIZE];
3334         struct st_request *SRpnt;
3335
3336         memset(scmd, 0, MAX_COMMAND_SIZE);
3337         scmd[0] = FORMAT_UNIT;
3338         scmd[2] = format;
3339         if (STp->immediate) {
3340                 scmd[1] |= 1;           /* Don't wait for completion */
3341                 timeout = STp->device->request_queue->rq_timeout;
3342         }
3343         DEBC_printk(STp, "Sending FORMAT MEDIUM\n");
3344         SRpnt = st_do_scsi(NULL, STp, scmd, 0, DMA_NONE,
3345                            timeout, MAX_RETRIES, 1);
3346         if (!SRpnt)
3347                 result = STp->buffer->syscall_result;
3348         return result;
3349 }
3350
3351
3352 /* Partition the tape into two partitions if size > 0 or one partition if
3353    size == 0.
3354
3355    The block descriptors are read and written because Sony SDT-7000 does not
3356    work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
3357
3358    My HP C1533A drive returns only one partition size field. This is used to
3359    set the size of partition 1. There is no size field for the default partition.
3360    Michael Schaefer's Sony SDT-7000 returns two descriptors and the second is
3361    used to set the size of partition 1 (this is what the SCSI-3 standard specifies).
3362    The following algorithm is used to accommodate both drives: if the number of
3363    partition size fields is greater than the maximum number of additional partitions
3364    in the mode page, the second field is used. Otherwise the first field is used.
3365
3366    For Seagate DDS drives the page length must be 8 when no partitions is defined
3367    and 10 when 1 partition is defined (information from Eric Lee Green). This is
3368    is acceptable also to some other old drives and enforced if the first partition
3369    size field is used for the first additional partition size.
3370
3371    For drives that advertize SCSI-3 or newer, use the SSC-3 methods.
3372  */
3373 static int partition_tape(struct scsi_tape *STp, int size)
3374 {
3375         int result;
3376         int target_partition;
3377         bool scsi3 = STp->device->scsi_level >= SCSI_3, needs_format = false;
3378         int pgo, psd_cnt, psdo;
3379         int psum = PP_MSK_PSUM_MB, units = 0;
3380         unsigned char *bp;
3381
3382         result = read_mode_page(STp, PART_PAGE, 0);
3383         if (result) {
3384                 DEBC_printk(STp, "Can't read partition mode page.\n");
3385                 return result;
3386         }
3387         target_partition = 1;
3388         if (size < 0) {
3389                 target_partition = 0;
3390                 size = -size;
3391         }
3392
3393         /* The mode page is in the buffer. Let's modify it and write it. */
3394         bp = (STp->buffer)->b_data;
3395         pgo = MODE_HEADER_LENGTH + bp[MH_OFF_BDESCS_LENGTH];
3396         DEBC_printk(STp, "Partition page length is %d bytes.\n",
3397                     bp[pgo + MP_OFF_PAGE_LENGTH] + 2);
3398
3399         psd_cnt = (bp[pgo + MP_OFF_PAGE_LENGTH] + 2 - PART_PAGE_FIXED_LENGTH) / 2;
3400
3401         if (scsi3) {
3402                 needs_format = (bp[pgo + PP_OFF_FLAGS] & PP_MSK_POFM) != 0;
3403                 if (needs_format && size == 0) {
3404                         /* No need to write the mode page when clearing
3405                          *  partitioning
3406                          */
3407                         DEBC_printk(STp, "Formatting tape with one partition.\n");
3408                         result = format_medium(STp, 0);
3409                         goto out;
3410                 }
3411                 if (needs_format)  /* Leave the old value for HP DATs claiming SCSI_3 */
3412                         psd_cnt = 2;
3413                 if ((bp[pgo + PP_OFF_FLAGS] & PP_MSK_PSUM_UNITS) == PP_MSK_PSUM_UNITS) {
3414                         /* Use units scaling for large partitions if the device
3415                          * suggests it and no precision lost. Required for IBM
3416                          * TS1140/50 drives that don't support MB units.
3417                          */
3418                         if (size >= 1000 && (size % 1000) == 0) {
3419                                 size /= 1000;
3420                                 psum = PP_MSK_PSUM_UNITS;
3421                                 units = 9; /* GB */
3422                         }
3423                 }
3424                 /* Try it anyway if too large to specify in MB */
3425                 if (psum == PP_MSK_PSUM_MB && size >= 65534) {
3426                         size /= 1000;
3427                         psum = PP_MSK_PSUM_UNITS;
3428                         units = 9;  /* GB */
3429                 }
3430         }
3431
3432         if (size >= 65535 ||  /* Does not fit into two bytes */
3433             (target_partition == 0 && psd_cnt < 2)) {
3434                 result = -EINVAL;
3435                 goto out;
3436         }
3437
3438         psdo = pgo + PART_PAGE_FIXED_LENGTH;
3439         /* The second condition is for HP DDS which use only one partition size
3440          * descriptor
3441          */
3442         if (target_partition > 0 &&
3443             (psd_cnt > bp[pgo + PP_OFF_MAX_ADD_PARTS] ||
3444              bp[pgo + PP_OFF_MAX_ADD_PARTS] != 1)) {
3445                 bp[psdo] = bp[psdo + 1] = 0xff;  /* Rest to partition 0 */
3446                 psdo += 2;
3447         }
3448         memset(bp + psdo, 0, bp[pgo + PP_OFF_NBR_ADD_PARTS] * 2);
3449
3450         DEBC_printk(STp, "psd_cnt %d, max.parts %d, nbr_parts %d\n",
3451                     psd_cnt, bp[pgo + PP_OFF_MAX_ADD_PARTS],
3452                     bp[pgo + PP_OFF_NBR_ADD_PARTS]);
3453
3454         if (size == 0) {
3455                 bp[pgo + PP_OFF_NBR_ADD_PARTS] = 0;
3456                 if (psd_cnt <= bp[pgo + PP_OFF_MAX_ADD_PARTS])
3457                     bp[pgo + MP_OFF_PAGE_LENGTH] = 6;
3458                 DEBC_printk(STp, "Formatting tape with one partition.\n");
3459         } else {
3460                 bp[psdo] = (size >> 8) & 0xff;
3461                 bp[psdo + 1] = size & 0xff;
3462                 if (target_partition == 0)
3463                         bp[psdo + 2] = bp[psdo + 3] = 0xff;
3464                 bp[pgo + 3] = 1;
3465                 if (bp[pgo + MP_OFF_PAGE_LENGTH] < 8)
3466                     bp[pgo + MP_OFF_PAGE_LENGTH] = 8;
3467                 DEBC_printk(STp,
3468                             "Formatting tape with two partitions (%i = %d MB).\n",
3469                             target_partition, units > 0 ? size * 1000 : size);
3470         }
3471         bp[pgo + PP_OFF_PART_UNITS] = 0;
3472         bp[pgo + PP_OFF_RESERVED] = 0;
3473         if (size != 1 || units != 0) {
3474                 bp[pgo + PP_OFF_FLAGS] = PP_BIT_IDP | psum |
3475                         (bp[pgo + PP_OFF_FLAGS] & 0x07);
3476                 bp[pgo + PP_OFF_PART_UNITS] = units;
3477         } else
3478                 bp[pgo + PP_OFF_FLAGS] = PP_BIT_FDP |
3479                         (bp[pgo + PP_OFF_FLAGS] & 0x1f);
3480         bp[pgo + MP_OFF_PAGE_LENGTH] = 6 + psd_cnt * 2;
3481
3482         result = write_mode_page(STp, PART_PAGE, 1);
3483
3484         if (!result && needs_format)
3485                 result = format_medium(STp, 1);
3486
3487         if (result) {
3488                 st_printk(KERN_INFO, STp, "Partitioning of tape failed.\n");
3489                 result = (-EIO);
3490         }
3491
3492 out:
3493         return result;
3494 }
3495 \f
3496
3497
3498 /* The ioctl command */
3499 static long st_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
3500 {
3501         int i, cmd_nr, cmd_type, bt;
3502         int retval = 0;
3503         unsigned int blk;
3504         struct scsi_tape *STp = file->private_data;
3505         struct st_modedef *STm;
3506         struct st_partstat *STps;
3507         void __user *p = (void __user *)arg;
3508
3509         if (mutex_lock_interruptible(&STp->lock))
3510                 return -ERESTARTSYS;
3511
3512         DEB(
3513         if (debugging && !STp->in_use) {
3514                 st_printk(ST_DEB_MSG, STp, "Incorrect device.\n");
3515                 retval = (-EIO);
3516                 goto out;
3517         } ) /* end DEB */
3518
3519         STm = &(STp->modes[STp->current_mode]);
3520         STps = &(STp->ps[STp->partition]);
3521
3522         /*
3523          * If we are in the middle of error recovery, don't let anyone
3524          * else try and use this device.  Also, if error recovery fails, it
3525          * may try and take the device offline, in which case all further
3526          * access to the device is prohibited.
3527          */
3528         retval = scsi_ioctl_block_when_processing_errors(STp->device, cmd_in,
3529                         file->f_flags & O_NDELAY);
3530         if (retval)
3531                 goto out;
3532
3533         cmd_type = _IOC_TYPE(cmd_in);
3534         cmd_nr = _IOC_NR(cmd_in);
3535
3536         if (cmd_type == _IOC_TYPE(MTIOCTOP) && cmd_nr == _IOC_NR(MTIOCTOP)) {
3537                 struct mtop mtc;
3538
3539                 if (_IOC_SIZE(cmd_in) != sizeof(mtc)) {
3540                         retval = (-EINVAL);
3541                         goto out;
3542                 }
3543
3544                 i = copy_from_user(&mtc, p, sizeof(struct mtop));
3545                 if (i) {
3546                         retval = (-EFAULT);
3547                         goto out;
3548                 }
3549
3550                 if (mtc.mt_op == MTSETDRVBUFFER && !capable(CAP_SYS_ADMIN)) {
3551                         st_printk(KERN_WARNING, STp,
3552                                   "MTSETDRVBUFFER only allowed for root.\n");
3553                         retval = (-EPERM);
3554                         goto out;
3555                 }
3556                 if (!STm->defined &&
3557                     (mtc.mt_op != MTSETDRVBUFFER &&
3558                      (mtc.mt_count & MT_ST_OPTIONS) == 0)) {
3559                         retval = (-ENXIO);
3560                         goto out;
3561                 }
3562
3563                 if (!STp->pos_unknown) {
3564
3565                         if (STps->eof == ST_FM_HIT) {
3566                                 if (mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3567                                     mtc.mt_op == MTEOM) {
3568                                         mtc.mt_count -= 1;
3569                                         if (STps->drv_file >= 0)
3570                                                 STps->drv_file += 1;
3571                                 } else if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM) {
3572                                         mtc.mt_count += 1;
3573                                         if (STps->drv_file >= 0)
3574                                                 STps->drv_file += 1;
3575                                 }
3576                         }
3577
3578                         if (mtc.mt_op == MTSEEK) {
3579                                 /* Old position must be restored if partition will be
3580                                    changed */
3581                                 i = !STp->can_partitions ||
3582                                     (STp->new_partition != STp->partition);
3583                         } else {
3584                                 i = mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3585                                     mtc.mt_op == MTRETEN || mtc.mt_op == MTEOM ||
3586                                     mtc.mt_op == MTLOCK || mtc.mt_op == MTLOAD ||
3587                                     mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3588                                     mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM ||
3589                                     mtc.mt_op == MTCOMPRESSION;
3590                         }
3591                         i = flush_buffer(STp, i);
3592                         if (i < 0) {
3593                                 retval = i;
3594                                 goto out;
3595                         }
3596                         if (STps->rw == ST_WRITING &&
3597                             (mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3598                              mtc.mt_op == MTSEEK ||
3599                              mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)) {
3600                                 i = st_int_ioctl(STp, MTWEOF, 1);
3601                                 if (i < 0) {
3602                                         retval = i;
3603                                         goto out;
3604                                 }
3605                                 if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)
3606                                         mtc.mt_count++;
3607                                 STps->rw = ST_IDLE;
3608                              }
3609
3610                 } else {
3611                         /*
3612                          * If there was a bus reset, block further access
3613                          * to this device.  If the user wants to rewind the tape,
3614                          * then reset the flag and allow access again.
3615                          */
3616                         if (mtc.mt_op != MTREW &&
3617                             mtc.mt_op != MTOFFL &&
3618                             mtc.mt_op != MTRETEN &&
3619                             mtc.mt_op != MTERASE &&
3620                             mtc.mt_op != MTSEEK &&
3621                             mtc.mt_op != MTEOM) {
3622                                 retval = (-EIO);
3623                                 goto out;
3624                         }
3625                         reset_state(STp);
3626                         /* remove this when the midlevel properly clears was_reset */
3627                         STp->device->was_reset = 0;
3628                 }
3629
3630                 if (mtc.mt_op != MTNOP && mtc.mt_op != MTSETBLK &&
3631                     mtc.mt_op != MTSETDENSITY && mtc.mt_op != MTWSM &&
3632                     mtc.mt_op != MTSETDRVBUFFER && mtc.mt_op != MTSETPART)
3633                         STps->rw = ST_IDLE;     /* Prevent automatic WEOF and fsf */
3634
3635                 if (mtc.mt_op == MTOFFL && STp->door_locked != ST_UNLOCKED)
3636                         do_door_lock(STp, 0);   /* Ignore result! */
3637
3638                 if (mtc.mt_op == MTSETDRVBUFFER &&
3639                     (mtc.mt_count & MT_ST_OPTIONS) != 0) {
3640                         retval = st_set_options(STp, mtc.mt_count);
3641                         goto out;
3642                 }
3643
3644                 if (mtc.mt_op == MTSETPART) {
3645                         if (!STp->can_partitions ||
3646                             mtc.mt_count < 0 || mtc.mt_count >= ST_NBR_PARTITIONS) {
3647                                 retval = (-EINVAL);
3648                                 goto out;
3649                         }
3650                         if (mtc.mt_count >= STp->nbr_partitions &&
3651                             (STp->nbr_partitions = nbr_partitions(STp)) < 0) {
3652                                 retval = (-EIO);
3653                                 goto out;
3654                         }
3655                         if (mtc.mt_count >= STp->nbr_partitions) {
3656                                 retval = (-EINVAL);
3657                                 goto out;
3658                         }
3659                         STp->new_partition = mtc.mt_count;
3660                         retval = 0;
3661                         goto out;
3662                 }
3663
3664                 if (mtc.mt_op == MTMKPART) {
3665                         if (!STp->can_partitions) {
3666                                 retval = (-EINVAL);
3667                                 goto out;
3668                         }
3669                         i = do_load_unload(STp, file, 1);
3670                         if (i < 0) {
3671                                 retval = i;
3672                                 goto out;
3673                         }
3674                         i = partition_tape(STp, mtc.mt_count);
3675                         if (i < 0) {
3676                                 retval = i;
3677                                 goto out;
3678                         }
3679                         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
3680                                 STp->ps[i].rw = ST_IDLE;
3681                                 STp->ps[i].at_sm = 0;
3682                                 STp->ps[i].last_block_valid = 0;
3683                         }
3684                         STp->partition = STp->new_partition = 0;
3685                         STp->nbr_partitions = mtc.mt_count != 0 ? 2 : 1;
3686                         STps->drv_block = STps->drv_file = 0;
3687                         retval = 0;
3688                         goto out;
3689                 }
3690
3691                 if (mtc.mt_op == MTSEEK) {
3692                         i = set_location(STp, mtc.mt_count, STp->new_partition, 0);
3693                         if (!STp->can_partitions)
3694                                 STp->ps[0].rw = ST_IDLE;
3695                         retval = i;
3696                         goto out;
3697                 }
3698
3699                 if (mtc.mt_op == MTUNLOAD || mtc.mt_op == MTOFFL) {
3700                         retval = do_load_unload(STp, file, 0);
3701                         goto out;
3702                 }
3703
3704                 if (mtc.mt_op == MTLOAD) {
3705                         retval = do_load_unload(STp, file, max(1, mtc.mt_count));
3706                         goto out;
3707                 }
3708
3709                 if (mtc.mt_op == MTLOCK || mtc.mt_op == MTUNLOCK) {
3710                         retval = do_door_lock(STp, (mtc.mt_op == MTLOCK));
3711                         goto out;
3712                 }
3713
3714                 if (STp->can_partitions && STp->ready == ST_READY &&
3715                     (i = switch_partition(STp)) < 0) {
3716                         retval = i;
3717                         goto out;
3718                 }
3719
3720                 if (mtc.mt_op == MTCOMPRESSION)
3721                         retval = st_compression(STp, (mtc.mt_count & 1));
3722                 else
3723                         retval = st_int_ioctl(STp, mtc.mt_op, mtc.mt_count);
3724                 goto out;
3725         }
3726         if (!STm->defined) {
3727                 retval = (-ENXIO);
3728                 goto out;
3729         }
3730
3731         if ((i = flush_buffer(STp, 0)) < 0) {
3732                 retval = i;
3733                 goto out;
3734         }
3735         if (STp->can_partitions &&
3736             (i = switch_partition(STp)) < 0) {
3737                 retval = i;
3738                 goto out;
3739         }
3740
3741         if (cmd_type == _IOC_TYPE(MTIOCGET) && cmd_nr == _IOC_NR(MTIOCGET)) {
3742                 struct mtget mt_status;
3743
3744                 if (_IOC_SIZE(cmd_in) != sizeof(struct mtget)) {
3745                          retval = (-EINVAL);
3746                          goto out;
3747                 }
3748
3749                 mt_status.mt_type = STp->tape_type;
3750                 mt_status.mt_dsreg =
3751                     ((STp->block_size << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK) |
3752                     ((STp->density << MT_ST_DENSITY_SHIFT) & MT_ST_DENSITY_MASK);
3753                 mt_status.mt_blkno = STps->drv_block;
3754                 mt_status.mt_fileno = STps->drv_file;
3755                 if (STp->block_size != 0) {
3756                         if (STps->rw == ST_WRITING)
3757                                 mt_status.mt_blkno +=
3758                                     (STp->buffer)->buffer_bytes / STp->block_size;
3759                         else if (STps->rw == ST_READING)
3760                                 mt_status.mt_blkno -=
3761                                         ((STp->buffer)->buffer_bytes +
3762                                          STp->block_size - 1) / STp->block_size;
3763                 }
3764
3765                 mt_status.mt_gstat = 0;
3766                 if (STp->drv_write_prot)
3767                         mt_status.mt_gstat |= GMT_WR_PROT(0xffffffff);
3768                 if (mt_status.mt_blkno == 0) {
3769                         if (mt_status.mt_fileno == 0)
3770                                 mt_status.mt_gstat |= GMT_BOT(0xffffffff);
3771                         else
3772                                 mt_status.mt_gstat |= GMT_EOF(0xffffffff);
3773                 }
3774                 mt_status.mt_erreg = (STp->recover_reg << MT_ST_SOFTERR_SHIFT);
3775                 mt_status.mt_resid = STp->partition;
3776                 if (STps->eof == ST_EOM_OK || STps->eof == ST_EOM_ERROR)
3777                         mt_status.mt_gstat |= GMT_EOT(0xffffffff);
3778                 else if (STps->eof >= ST_EOM_OK)
3779                         mt_status.mt_gstat |= GMT_EOD(0xffffffff);
3780                 if (STp->density == 1)
3781                         mt_status.mt_gstat |= GMT_D_800(0xffffffff);
3782                 else if (STp->density == 2)
3783                         mt_status.mt_gstat |= GMT_D_1600(0xffffffff);
3784                 else if (STp->density == 3)
3785                         mt_status.mt_gstat |= GMT_D_6250(0xffffffff);
3786                 if (STp->ready == ST_READY)
3787                         mt_status.mt_gstat |= GMT_ONLINE(0xffffffff);
3788                 if (STp->ready == ST_NO_TAPE)
3789                         mt_status.mt_gstat |= GMT_DR_OPEN(0xffffffff);
3790                 if (STps->at_sm)
3791                         mt_status.mt_gstat |= GMT_SM(0xffffffff);
3792                 if (STm->do_async_writes ||
3793                     (STm->do_buffer_writes && STp->block_size != 0) ||
3794                     STp->drv_buffer != 0)
3795                         mt_status.mt_gstat |= GMT_IM_REP_EN(0xffffffff);
3796                 if (STp->cleaning_req)
3797                         mt_status.mt_gstat |= GMT_CLN(0xffffffff);
3798
3799                 i = copy_to_user(p, &mt_status, sizeof(struct mtget));
3800                 if (i) {
3801                         retval = (-EFAULT);
3802                         goto out;
3803                 }
3804
3805                 STp->recover_reg = 0;           /* Clear after read */
3806                 retval = 0;
3807                 goto out;
3808         }                       /* End of MTIOCGET */
3809         if (cmd_type == _IOC_TYPE(MTIOCPOS) && cmd_nr == _IOC_NR(MTIOCPOS)) {
3810                 struct mtpos mt_pos;
3811                 if (_IOC_SIZE(cmd_in) != sizeof(struct mtpos)) {
3812                          retval = (-EINVAL);
3813                          goto out;
3814                 }
3815                 if ((i = get_location(STp, &blk, &bt, 0)) < 0) {
3816                         retval = i;
3817                         goto out;
3818                 }
3819                 mt_pos.mt_blkno = blk;
3820                 i = copy_to_user(p, &mt_pos, sizeof(struct mtpos));
3821                 if (i)
3822                         retval = (-EFAULT);
3823                 goto out;
3824         }
3825         mutex_unlock(&STp->lock);
3826         switch (cmd_in) {
3827                 case SCSI_IOCTL_GET_IDLUN:
3828                 case SCSI_IOCTL_GET_BUS_NUMBER:
3829                         break;
3830                 default:
3831                         if ((cmd_in == SG_IO ||
3832                              cmd_in == SCSI_IOCTL_SEND_COMMAND ||
3833                              cmd_in == CDROM_SEND_PACKET) &&
3834                             !capable(CAP_SYS_RAWIO))
3835                                 i = -EPERM;
3836                         else
3837                                 i = scsi_cmd_ioctl(STp->disk->queue, STp->disk,
3838                                                    file->f_mode, cmd_in, p);
3839                         if (i != -ENOTTY)
3840                                 return i;
3841                         break;
3842         }
3843         retval = scsi_ioctl(STp->device, cmd_in, p);
3844         if (!retval && cmd_in == SCSI_IOCTL_STOP_UNIT) { /* unload */
3845                 STp->rew_at_close = 0;
3846                 STp->ready = ST_NO_TAPE;
3847         }
3848         return retval;
3849
3850  out:
3851         mutex_unlock(&STp->lock);
3852         return retval;
3853 }
3854
3855 #ifdef CONFIG_COMPAT
3856 static long st_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
3857 {
3858         struct scsi_tape *STp = file->private_data;
3859         struct scsi_device *sdev = STp->device;
3860         int ret = -ENOIOCTLCMD;
3861         if (sdev->host->hostt->compat_ioctl) {
3862
3863                 ret = sdev->host->hostt->compat_ioctl(sdev, cmd, (void __user *)arg);
3864
3865         }
3866         return ret;
3867 }
3868 #endif
3869
3870 \f
3871
3872 /* Try to allocate a new tape buffer. Calling function must not hold
3873    dev_arr_lock. */
3874 static struct st_buffer *new_tape_buffer(int need_dma, int max_sg)
3875 {
3876         struct st_buffer *tb;
3877
3878         tb = kzalloc(sizeof(struct st_buffer), GFP_KERNEL);
3879         if (!tb) {
3880                 printk(KERN_NOTICE "st: Can't allocate new tape buffer.\n");
3881                 return NULL;
3882         }
3883         tb->frp_segs = 0;
3884         tb->use_sg = max_sg;
3885         tb->dma = need_dma;
3886         tb->buffer_size = 0;
3887
3888         tb->reserved_pages = kcalloc(max_sg, sizeof(struct page *),
3889                                      GFP_KERNEL);
3890         if (!tb->reserved_pages) {
3891                 kfree(tb);
3892                 return NULL;
3893         }
3894
3895         return tb;
3896 }
3897
3898
3899 /* Try to allocate enough space in the tape buffer */
3900 #define ST_MAX_ORDER 6
3901
3902 static int enlarge_buffer(struct st_buffer * STbuffer, int new_size, int need_dma)
3903 {
3904         int segs, max_segs, b_size, order, got;
3905         gfp_t priority;
3906
3907         if (new_size <= STbuffer->buffer_size)
3908                 return 1;
3909
3910         if (STbuffer->buffer_size <= PAGE_SIZE)
3911                 normalize_buffer(STbuffer);  /* Avoid extra segment */
3912
3913         max_segs = STbuffer->use_sg;
3914
3915         priority = GFP_KERNEL | __GFP_NOWARN;
3916         if (need_dma)
3917                 priority |= GFP_DMA;
3918
3919         if (STbuffer->cleared)
3920                 priority |= __GFP_ZERO;
3921
3922         if (STbuffer->frp_segs) {
3923                 order = STbuffer->reserved_page_order;
3924                 b_size = PAGE_SIZE << order;
3925         } else {
3926                 for (b_size = PAGE_SIZE, order = 0;
3927                      order < ST_MAX_ORDER &&
3928                              max_segs * (PAGE_SIZE << order) < new_size;
3929                      order++, b_size *= 2)
3930                         ;  /* empty */
3931                 STbuffer->reserved_page_order = order;
3932         }
3933         if (max_segs * (PAGE_SIZE << order) < new_size) {
3934                 if (order == ST_MAX_ORDER)
3935                         return 0;
3936                 normalize_buffer(STbuffer);
3937                 return enlarge_buffer(STbuffer, new_size, need_dma);
3938         }
3939
3940         for (segs = STbuffer->frp_segs, got = STbuffer->buffer_size;
3941              segs < max_segs && got < new_size;) {
3942                 struct page *page;
3943
3944                 page = alloc_pages(priority, order);
3945                 if (!page) {
3946                         DEB(STbuffer->buffer_size = got);
3947                         normalize_buffer(STbuffer);
3948                         return 0;
3949                 }
3950
3951                 STbuffer->frp_segs += 1;
3952                 got += b_size;
3953                 STbuffer->buffer_size = got;
3954                 STbuffer->reserved_pages[segs] = page;
3955                 segs++;
3956         }
3957         STbuffer->b_data = page_address(STbuffer->reserved_pages[0]);
3958
3959         return 1;
3960 }
3961
3962
3963 /* Make sure that no data from previous user is in the internal buffer */
3964 static void clear_buffer(struct st_buffer * st_bp)
3965 {
3966         int i;
3967
3968         for (i=0; i < st_bp->frp_segs; i++)
3969                 memset(page_address(st_bp->reserved_pages[i]), 0,
3970                        PAGE_SIZE << st_bp->reserved_page_order);
3971         st_bp->cleared = 1;
3972 }
3973
3974
3975 /* Release the extra buffer */
3976 static void normalize_buffer(struct st_buffer * STbuffer)
3977 {
3978         int i, order = STbuffer->reserved_page_order;
3979
3980         for (i = 0; i < STbuffer->frp_segs; i++) {
3981                 __free_pages(STbuffer->reserved_pages[i], order);
3982                 STbuffer->buffer_size -= (PAGE_SIZE << order);
3983         }
3984         STbuffer->frp_segs = 0;
3985         STbuffer->sg_segs = 0;
3986         STbuffer->reserved_page_order = 0;
3987         STbuffer->map_data.offset = 0;
3988 }
3989
3990
3991 /* Move data from the user buffer to the tape buffer. Returns zero (success) or
3992    negative error code. */
3993 static int append_to_buffer(const char __user *ubp, struct st_buffer * st_bp, int do_count)
3994 {
3995         int i, cnt, res, offset;
3996         int length = PAGE_SIZE << st_bp->reserved_page_order;
3997
3998         for (i = 0, offset = st_bp->buffer_bytes;
3999              i < st_bp->frp_segs && offset >= length; i++)
4000                 offset -= length;
4001         if (i == st_bp->frp_segs) {     /* Should never happen */
4002                 printk(KERN_WARNING "st: append_to_buffer offset overflow.\n");
4003                 return (-EIO);
4004         }
4005         for (; i < st_bp->frp_segs && do_count > 0; i++) {
4006                 struct page *page = st_bp->reserved_pages[i];
4007                 cnt = length - offset < do_count ? length - offset : do_count;
4008                 res = copy_from_user(page_address(page) + offset, ubp, cnt);
4009                 if (res)
4010                         return (-EFAULT);
4011                 do_count -= cnt;
4012                 st_bp->buffer_bytes += cnt;
4013                 ubp += cnt;
4014                 offset = 0;
4015         }
4016         if (do_count) /* Should never happen */
4017                 return (-EIO);
4018
4019         return 0;
4020 }
4021
4022
4023 /* Move data from the tape buffer to the user buffer. Returns zero (success) or
4024    negative error code. */
4025 static int from_buffer(struct st_buffer * st_bp, char __user *ubp, int do_count)
4026 {
4027         int i, cnt, res, offset;
4028         int length = PAGE_SIZE << st_bp->reserved_page_order;
4029
4030         for (i = 0, offset = st_bp->read_pointer;
4031              i < st_bp->frp_segs && offset >= length; i++)
4032                 offset -= length;
4033         if (i == st_bp->frp_segs) {     /* Should never happen */
4034                 printk(KERN_WARNING "st: from_buffer offset overflow.\n");
4035                 return (-EIO);
4036         }
4037         for (; i < st_bp->frp_segs && do_count > 0; i++) {
4038                 struct page *page = st_bp->reserved_pages[i];
4039                 cnt = length - offset < do_count ? length - offset : do_count;
4040                 res = copy_to_user(ubp, page_address(page) + offset, cnt);
4041                 if (res)
4042                         return (-EFAULT);
4043                 do_count -= cnt;
4044                 st_bp->buffer_bytes -= cnt;
4045                 st_bp->read_pointer += cnt;
4046                 ubp += cnt;
4047                 offset = 0;
4048         }
4049         if (do_count) /* Should never happen */
4050                 return (-EIO);
4051
4052         return 0;
4053 }
4054
4055
4056 /* Move data towards start of buffer */
4057 static void move_buffer_data(struct st_buffer * st_bp, int offset)
4058 {
4059         int src_seg, dst_seg, src_offset = 0, dst_offset;
4060         int count, total;
4061         int length = PAGE_SIZE << st_bp->reserved_page_order;
4062
4063         if (offset == 0)
4064                 return;
4065
4066         total=st_bp->buffer_bytes - offset;
4067         for (src_seg=0; src_seg < st_bp->frp_segs; src_seg++) {
4068                 src_offset = offset;
4069                 if (src_offset < length)
4070                         break;
4071                 offset -= length;
4072         }
4073
4074         st_bp->buffer_bytes = st_bp->read_pointer = total;
4075         for (dst_seg=dst_offset=0; total > 0; ) {
4076                 struct page *dpage = st_bp->reserved_pages[dst_seg];
4077                 struct page *spage = st_bp->reserved_pages[src_seg];
4078
4079                 count = min(length - dst_offset, length - src_offset);
4080                 memmove(page_address(dpage) + dst_offset,
4081                         page_address(spage) + src_offset, count);
4082                 src_offset += count;
4083                 if (src_offset >= length) {
4084                         src_seg++;
4085                         src_offset = 0;
4086                 }
4087                 dst_offset += count;
4088                 if (dst_offset >= length) {
4089                         dst_seg++;
4090                         dst_offset = 0;
4091                 }
4092                 total -= count;
4093         }
4094 }
4095
4096 /* Validate the options from command line or module parameters */
4097 static void validate_options(void)
4098 {
4099         if (buffer_kbs > 0)
4100                 st_fixed_buffer_size = buffer_kbs * ST_KILOBYTE;
4101         if (max_sg_segs >= ST_FIRST_SG)
4102                 st_max_sg_segs = max_sg_segs;
4103 }
4104
4105 #ifndef MODULE
4106 /* Set the boot options. Syntax is defined in Documenation/scsi/st.txt.
4107  */
4108 static int __init st_setup(char *str)
4109 {
4110         int i, len, ints[5];
4111         char *stp;
4112
4113         stp = get_options(str, ARRAY_SIZE(ints), ints);
4114
4115         if (ints[0] > 0) {
4116                 for (i = 0; i < ints[0] && i < ARRAY_SIZE(parms); i++)
4117                         if (parms[i].val)
4118                                 *parms[i].val = ints[i + 1];
4119         } else {
4120                 while (stp != NULL) {
4121                         for (i = 0; i < ARRAY_SIZE(parms); i++) {
4122                                 len = strlen(parms[i].name);
4123                                 if (!strncmp(stp, parms[i].name, len) &&
4124                                     (*(stp + len) == ':' || *(stp + len) == '=')) {
4125                                         if (parms[i].val)
4126                                                 *parms[i].val =
4127                                                         simple_strtoul(stp + len + 1, NULL, 0);
4128                                         else
4129                                                 printk(KERN_WARNING "st: Obsolete parameter %s\n",
4130                                                        parms[i].name);
4131                                         break;
4132                                 }
4133                         }
4134                         if (i >= ARRAY_SIZE(parms))
4135                                  printk(KERN_WARNING "st: invalid parameter in '%s'\n",
4136                                         stp);
4137                         stp = strchr(stp, ',');
4138                         if (stp)
4139                                 stp++;
4140                 }
4141         }
4142
4143         validate_options();
4144
4145         return 1;
4146 }
4147
4148 __setup("st=", st_setup);
4149
4150 #endif
4151
4152 static const struct file_operations st_fops =
4153 {
4154         .owner =        THIS_MODULE,
4155         .read =         st_read,
4156         .write =        st_write,
4157         .unlocked_ioctl = st_ioctl,
4158 #ifdef CONFIG_COMPAT
4159         .compat_ioctl = st_compat_ioctl,
4160 #endif
4161         .open =         st_open,
4162         .flush =        st_flush,
4163         .release =      st_release,
4164         .llseek =       noop_llseek,
4165 };
4166
4167 static int create_one_cdev(struct scsi_tape *tape, int mode, int rew)
4168 {
4169         int i, error;
4170         dev_t cdev_devno;
4171         struct cdev *cdev;
4172         struct device *dev;
4173         struct st_modedef *STm = &(tape->modes[mode]);
4174         char name[10];
4175         int dev_num = tape->index;
4176
4177         cdev_devno = MKDEV(SCSI_TAPE_MAJOR, TAPE_MINOR(dev_num, mode, rew));
4178
4179         cdev = cdev_alloc();
4180         if (!cdev) {
4181                 pr_err("st%d: out of memory. Device not attached.\n", dev_num);
4182                 error = -ENOMEM;
4183                 goto out;
4184         }
4185         cdev->owner = THIS_MODULE;
4186         cdev->ops = &st_fops;
4187         STm->cdevs[rew] = cdev;
4188
4189         error = cdev_add(cdev, cdev_devno, 1);
4190         if (error) {
4191                 pr_err("st%d: Can't add %s-rewind mode %d\n", dev_num,
4192                        rew ? "non" : "auto", mode);
4193                 pr_err("st%d: Device not attached.\n", dev_num);
4194                 goto out_free;
4195         }
4196
4197         i = mode << (4 - ST_NBR_MODE_BITS);
4198         snprintf(name, 10, "%s%s%s", rew ? "n" : "",
4199                  tape->disk->disk_name, st_formats[i]);
4200
4201         dev = device_create(&st_sysfs_class, &tape->device->sdev_gendev,
4202                             cdev_devno, &tape->modes[mode], "%s", name);
4203         if (IS_ERR(dev)) {
4204                 pr_err("st%d: device_create failed\n", dev_num);
4205                 error = PTR_ERR(dev);
4206                 goto out_free;
4207         }
4208
4209         STm->devs[rew] = dev;
4210
4211         return 0;
4212 out_free:
4213         cdev_del(STm->cdevs[rew]);
4214 out:
4215         STm->cdevs[rew] = NULL;
4216         STm->devs[rew] = NULL;
4217         return error;
4218 }
4219
4220 static int create_cdevs(struct scsi_tape *tape)
4221 {
4222         int mode, error;
4223         for (mode = 0; mode < ST_NBR_MODES; ++mode) {
4224                 error = create_one_cdev(tape, mode, 0);
4225                 if (error)
4226                         return error;
4227                 error = create_one_cdev(tape, mode, 1);
4228                 if (error)
4229                         return error;
4230         }
4231
4232         return sysfs_create_link(&tape->device->sdev_gendev.kobj,
4233                                  &tape->modes[0].devs[0]->kobj, "tape");
4234 }
4235
4236 static void remove_cdevs(struct scsi_tape *tape)
4237 {
4238         int mode, rew;
4239         sysfs_remove_link(&tape->device->sdev_gendev.kobj, "tape");
4240         for (mode = 0; mode < ST_NBR_MODES; mode++) {
4241                 struct st_modedef *STm = &(tape->modes[mode]);
4242                 for (rew = 0; rew < 2; rew++) {
4243                         if (STm->cdevs[rew])
4244                                 cdev_del(STm->cdevs[rew]);
4245                         if (STm->devs[rew])
4246                                 device_unregister(STm->devs[rew]);
4247                 }
4248         }
4249 }
4250
4251 static int st_probe(struct device *dev)
4252 {
4253         struct scsi_device *SDp = to_scsi_device(dev);
4254         struct gendisk *disk = NULL;
4255         struct scsi_tape *tpnt = NULL;
4256         struct st_modedef *STm;
4257         struct st_partstat *STps;
4258         struct st_buffer *buffer;
4259         int i, error;
4260         char *stp;
4261
4262         if (SDp->type != TYPE_TAPE)
4263                 return -ENODEV;
4264         if ((stp = st_incompatible(SDp))) {
4265                 sdev_printk(KERN_INFO, SDp, "Found incompatible tape\n");
4266                 sdev_printk(KERN_INFO, SDp,
4267                             "st: The suggested driver is %s.\n", stp);
4268                 return -ENODEV;
4269         }
4270
4271         scsi_autopm_get_device(SDp);
4272         i = queue_max_segments(SDp->request_queue);
4273         if (st_max_sg_segs < i)
4274                 i = st_max_sg_segs;
4275         buffer = new_tape_buffer((SDp->host)->unchecked_isa_dma, i);
4276         if (buffer == NULL) {
4277                 sdev_printk(KERN_ERR, SDp,
4278                             "st: Can't allocate new tape buffer. "
4279                             "Device not attached.\n");
4280                 goto out;
4281         }
4282
4283         disk = alloc_disk(1);
4284         if (!disk) {
4285                 sdev_printk(KERN_ERR, SDp,
4286                             "st: out of memory. Device not attached.\n");
4287                 goto out_buffer_free;
4288         }
4289
4290         tpnt = kzalloc(sizeof(struct scsi_tape), GFP_KERNEL);
4291         if (tpnt == NULL) {
4292                 sdev_printk(KERN_ERR, SDp,
4293                             "st: Can't allocate device descriptor.\n");
4294                 goto out_put_disk;
4295         }
4296         kref_init(&tpnt->kref);
4297         tpnt->disk = disk;
4298         disk->private_data = &tpnt->driver;
4299         /* SCSI tape doesn't register this gendisk via add_disk().  Manually
4300          * take queue reference that release_disk() expects. */
4301         if (!blk_get_queue(SDp->request_queue))
4302                 goto out_put_disk;
4303         disk->queue = SDp->request_queue;
4304         tpnt->driver = &st_template;
4305
4306         tpnt->device = SDp;
4307         if (SDp->scsi_level <= 2)
4308                 tpnt->tape_type = MT_ISSCSI1;
4309         else
4310                 tpnt->tape_type = MT_ISSCSI2;
4311
4312         tpnt->buffer = buffer;
4313         tpnt->buffer->last_SRpnt = NULL;
4314
4315         tpnt->inited = 0;
4316         tpnt->dirty = 0;
4317         tpnt->in_use = 0;
4318         tpnt->drv_buffer = 1;   /* Try buffering if no mode sense */
4319         tpnt->restr_dma = (SDp->host)->unchecked_isa_dma;
4320         tpnt->use_pf = (SDp->scsi_level >= SCSI_2);
4321         tpnt->density = 0;
4322         tpnt->do_auto_lock = ST_AUTO_LOCK;
4323         tpnt->can_bsr = (SDp->scsi_level > 2 ? 1 : ST_IN_FILE_POS); /* BSR mandatory in SCSI3 */
4324         tpnt->can_partitions = 0;
4325         tpnt->two_fm = ST_TWO_FM;
4326         tpnt->fast_mteom = ST_FAST_MTEOM;
4327         tpnt->scsi2_logical = ST_SCSI2LOGICAL;
4328         tpnt->sili = ST_SILI;
4329         tpnt->immediate = ST_NOWAIT;
4330         tpnt->immediate_filemark = 0;
4331         tpnt->default_drvbuffer = 0xff;         /* No forced buffering */
4332         tpnt->partition = 0;
4333         tpnt->new_partition = 0;
4334         tpnt->nbr_partitions = 0;
4335         blk_queue_rq_timeout(tpnt->device->request_queue, ST_TIMEOUT);
4336         tpnt->long_timeout = ST_LONG_TIMEOUT;
4337         tpnt->try_dio = try_direct_io && !SDp->host->unchecked_isa_dma;
4338
4339         for (i = 0; i < ST_NBR_MODES; i++) {
4340                 STm = &(tpnt->modes[i]);
4341                 STm->defined = 0;
4342                 STm->sysv = ST_SYSV;
4343                 STm->defaults_for_writes = 0;
4344                 STm->do_async_writes = ST_ASYNC_WRITES;
4345                 STm->do_buffer_writes = ST_BUFFER_WRITES;
4346                 STm->do_read_ahead = ST_READ_AHEAD;
4347                 STm->default_compression = ST_DONT_TOUCH;
4348                 STm->default_blksize = (-1);    /* No forced size */
4349                 STm->default_density = (-1);    /* No forced density */
4350                 STm->tape = tpnt;
4351         }
4352
4353         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
4354                 STps = &(tpnt->ps[i]);
4355                 STps->rw = ST_IDLE;
4356                 STps->eof = ST_NOEOF;
4357                 STps->at_sm = 0;
4358                 STps->last_block_valid = 0;
4359                 STps->drv_block = (-1);
4360                 STps->drv_file = (-1);
4361         }
4362
4363         tpnt->current_mode = 0;
4364         tpnt->modes[0].defined = 1;
4365
4366         tpnt->density_changed = tpnt->compression_changed =
4367             tpnt->blksize_changed = 0;
4368         mutex_init(&tpnt->lock);
4369
4370         idr_preload(GFP_KERNEL);
4371         spin_lock(&st_index_lock);
4372         error = idr_alloc(&st_index_idr, tpnt, 0, ST_MAX_TAPES + 1, GFP_NOWAIT);
4373         spin_unlock(&st_index_lock);
4374         idr_preload_end();
4375         if (error < 0) {
4376                 pr_warn("st: idr allocation failed: %d\n", error);
4377                 goto out_put_queue;
4378         }
4379         tpnt->index = error;
4380         sprintf(disk->disk_name, "st%d", tpnt->index);
4381         tpnt->stats = kzalloc(sizeof(struct scsi_tape_stats), GFP_KERNEL);
4382         if (tpnt->stats == NULL) {
4383                 sdev_printk(KERN_ERR, SDp,
4384                             "st: Can't allocate statistics.\n");
4385                 goto out_idr_remove;
4386         }
4387
4388         dev_set_drvdata(dev, tpnt);
4389
4390
4391         error = create_cdevs(tpnt);
4392         if (error)
4393                 goto out_remove_devs;
4394         scsi_autopm_put_device(SDp);
4395
4396         sdev_printk(KERN_NOTICE, SDp,
4397                     "Attached scsi tape %s\n", tape_name(tpnt));
4398         sdev_printk(KERN_INFO, SDp, "%s: try direct i/o: %s (alignment %d B)\n",
4399                     tape_name(tpnt), tpnt->try_dio ? "yes" : "no",
4400                     queue_dma_alignment(SDp->request_queue) + 1);
4401
4402         return 0;
4403
4404 out_remove_devs:
4405         remove_cdevs(tpnt);
4406         kfree(tpnt->stats);
4407 out_idr_remove:
4408         spin_lock(&st_index_lock);
4409         idr_remove(&st_index_idr, tpnt->index);
4410         spin_unlock(&st_index_lock);
4411 out_put_queue:
4412         blk_put_queue(disk->queue);
4413 out_put_disk:
4414         put_disk(disk);
4415         kfree(tpnt);
4416 out_buffer_free:
4417         kfree(buffer);
4418 out:
4419         scsi_autopm_put_device(SDp);
4420         return -ENODEV;
4421 };
4422
4423
4424 static int st_remove(struct device *dev)
4425 {
4426         struct scsi_tape *tpnt = dev_get_drvdata(dev);
4427         int index = tpnt->index;
4428
4429         scsi_autopm_get_device(to_scsi_device(dev));
4430         remove_cdevs(tpnt);
4431
4432         mutex_lock(&st_ref_mutex);
4433         kref_put(&tpnt->kref, scsi_tape_release);
4434         mutex_unlock(&st_ref_mutex);
4435         spin_lock(&st_index_lock);
4436         idr_remove(&st_index_idr, index);
4437         spin_unlock(&st_index_lock);
4438         return 0;
4439 }
4440
4441 /**
4442  *      scsi_tape_release - Called to free the Scsi_Tape structure
4443  *      @kref: pointer to embedded kref
4444  *
4445  *      st_ref_mutex must be held entering this routine.  Because it is
4446  *      called on last put, you should always use the scsi_tape_get()
4447  *      scsi_tape_put() helpers which manipulate the semaphore directly
4448  *      and never do a direct kref_put().
4449  **/
4450 static void scsi_tape_release(struct kref *kref)
4451 {
4452         struct scsi_tape *tpnt = to_scsi_tape(kref);
4453         struct gendisk *disk = tpnt->disk;
4454
4455         tpnt->device = NULL;
4456
4457         if (tpnt->buffer) {
4458                 normalize_buffer(tpnt->buffer);
4459                 kfree(tpnt->buffer->reserved_pages);
4460                 kfree(tpnt->buffer);
4461         }
4462
4463         disk->private_data = NULL;
4464         put_disk(disk);
4465         kfree(tpnt->stats);
4466         kfree(tpnt);
4467         return;
4468 }
4469
4470 static struct class st_sysfs_class = {
4471         .name = "scsi_tape",
4472         .dev_groups = st_dev_groups,
4473 };
4474
4475 static int __init init_st(void)
4476 {
4477         int err;
4478
4479         validate_options();
4480
4481         printk(KERN_INFO "st: Version %s, fixed bufsize %d, s/g segs %d\n",
4482                 verstr, st_fixed_buffer_size, st_max_sg_segs);
4483
4484         debugging = (debug_flag > 0) ? debug_flag : NO_DEBUG;
4485         if (debugging) {
4486                 printk(KERN_INFO "st: Debugging enabled debug_flag = %d\n",
4487                         debugging);
4488         }
4489
4490         err = class_register(&st_sysfs_class);
4491         if (err) {
4492                 pr_err("Unable register sysfs class for SCSI tapes\n");
4493                 return err;
4494         }
4495
4496         err = register_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4497                                      ST_MAX_TAPE_ENTRIES, "st");
4498         if (err) {
4499                 printk(KERN_ERR "Unable to get major %d for SCSI tapes\n",
4500                        SCSI_TAPE_MAJOR);
4501                 goto err_class;
4502         }
4503
4504         err = scsi_register_driver(&st_template.gendrv);
4505         if (err)
4506                 goto err_chrdev;
4507
4508         return 0;
4509
4510 err_chrdev:
4511         unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4512                                  ST_MAX_TAPE_ENTRIES);
4513 err_class:
4514         class_unregister(&st_sysfs_class);
4515         return err;
4516 }
4517
4518 static void __exit exit_st(void)
4519 {
4520         scsi_unregister_driver(&st_template.gendrv);
4521         unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4522                                  ST_MAX_TAPE_ENTRIES);
4523         class_unregister(&st_sysfs_class);
4524         idr_destroy(&st_index_idr);
4525         printk(KERN_INFO "st: Unloaded.\n");
4526 }
4527
4528 module_init(init_st);
4529 module_exit(exit_st);
4530
4531
4532 /* The sysfs driver interface. Read-only at the moment */
4533 static ssize_t try_direct_io_show(struct device_driver *ddp, char *buf)
4534 {
4535         return scnprintf(buf, PAGE_SIZE, "%d\n", try_direct_io);
4536 }
4537 static DRIVER_ATTR_RO(try_direct_io);
4538
4539 static ssize_t fixed_buffer_size_show(struct device_driver *ddp, char *buf)
4540 {
4541         return scnprintf(buf, PAGE_SIZE, "%d\n", st_fixed_buffer_size);
4542 }
4543 static DRIVER_ATTR_RO(fixed_buffer_size);
4544
4545 static ssize_t max_sg_segs_show(struct device_driver *ddp, char *buf)
4546 {
4547         return scnprintf(buf, PAGE_SIZE, "%d\n", st_max_sg_segs);
4548 }
4549 static DRIVER_ATTR_RO(max_sg_segs);
4550
4551 static ssize_t version_show(struct device_driver *ddd, char *buf)
4552 {
4553         return scnprintf(buf, PAGE_SIZE, "[%s]\n", verstr);
4554 }
4555 static DRIVER_ATTR_RO(version);
4556
4557 #if DEBUG
4558 static ssize_t debug_flag_store(struct device_driver *ddp,
4559         const char *buf, size_t count)
4560 {
4561 /* We only care what the first byte of the data is the rest is unused.
4562  * if it's a '1' we turn on debug and if it's a '0' we disable it. All
4563  * other values have -EINVAL returned if they are passed in.
4564  */
4565         if (count > 0) {
4566                 if (buf[0] == '0') {
4567                         debugging = NO_DEBUG;
4568                         return count;
4569                 } else if (buf[0] == '1') {
4570                         debugging = 1;
4571                         return count;
4572                 }
4573         }
4574         return -EINVAL;
4575 }
4576
4577 static ssize_t debug_flag_show(struct device_driver *ddp, char *buf)
4578 {
4579         return scnprintf(buf, PAGE_SIZE, "%d\n", debugging);
4580 }
4581 static DRIVER_ATTR_RW(debug_flag);
4582 #endif
4583
4584 static struct attribute *st_drv_attrs[] = {
4585         &driver_attr_try_direct_io.attr,
4586         &driver_attr_fixed_buffer_size.attr,
4587         &driver_attr_max_sg_segs.attr,
4588         &driver_attr_version.attr,
4589 #if DEBUG
4590         &driver_attr_debug_flag.attr,
4591 #endif
4592         NULL,
4593 };
4594 ATTRIBUTE_GROUPS(st_drv);
4595
4596 /* The sysfs simple class interface */
4597 static ssize_t
4598 defined_show(struct device *dev, struct device_attribute *attr, char *buf)
4599 {
4600         struct st_modedef *STm = dev_get_drvdata(dev);
4601         ssize_t l = 0;
4602
4603         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->defined);
4604         return l;
4605 }
4606 static DEVICE_ATTR_RO(defined);
4607
4608 static ssize_t
4609 default_blksize_show(struct device *dev, struct device_attribute *attr,
4610                      char *buf)
4611 {
4612         struct st_modedef *STm = dev_get_drvdata(dev);
4613         ssize_t l = 0;
4614
4615         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_blksize);
4616         return l;
4617 }
4618 static DEVICE_ATTR_RO(default_blksize);
4619
4620 static ssize_t
4621 default_density_show(struct device *dev, struct device_attribute *attr,
4622                      char *buf)
4623 {
4624         struct st_modedef *STm = dev_get_drvdata(dev);
4625         ssize_t l = 0;
4626         char *fmt;
4627
4628         fmt = STm->default_density >= 0 ? "0x%02x\n" : "%d\n";
4629         l = snprintf(buf, PAGE_SIZE, fmt, STm->default_density);
4630         return l;
4631 }
4632 static DEVICE_ATTR_RO(default_density);
4633
4634 static ssize_t
4635 default_compression_show(struct device *dev, struct device_attribute *attr,
4636                          char *buf)
4637 {
4638         struct st_modedef *STm = dev_get_drvdata(dev);
4639         ssize_t l = 0;
4640
4641         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_compression - 1);
4642         return l;
4643 }
4644 static DEVICE_ATTR_RO(default_compression);
4645
4646 static ssize_t
4647 options_show(struct device *dev, struct device_attribute *attr, char *buf)
4648 {
4649         struct st_modedef *STm = dev_get_drvdata(dev);
4650         struct scsi_tape *STp = STm->tape;
4651         int options;
4652         ssize_t l = 0;
4653
4654         options = STm->do_buffer_writes ? MT_ST_BUFFER_WRITES : 0;
4655         options |= STm->do_async_writes ? MT_ST_ASYNC_WRITES : 0;
4656         options |= STm->do_read_ahead ? MT_ST_READ_AHEAD : 0;
4657         DEB( options |= debugging ? MT_ST_DEBUGGING : 0 );
4658         options |= STp->two_fm ? MT_ST_TWO_FM : 0;
4659         options |= STp->fast_mteom ? MT_ST_FAST_MTEOM : 0;
4660         options |= STm->defaults_for_writes ? MT_ST_DEF_WRITES : 0;
4661         options |= STp->can_bsr ? MT_ST_CAN_BSR : 0;
4662         options |= STp->omit_blklims ? MT_ST_NO_BLKLIMS : 0;
4663         options |= STp->can_partitions ? MT_ST_CAN_PARTITIONS : 0;
4664         options |= STp->scsi2_logical ? MT_ST_SCSI2LOGICAL : 0;
4665         options |= STm->sysv ? MT_ST_SYSV : 0;
4666         options |= STp->immediate ? MT_ST_NOWAIT : 0;
4667         options |= STp->immediate_filemark ? MT_ST_NOWAIT_EOF : 0;
4668         options |= STp->sili ? MT_ST_SILI : 0;
4669
4670         l = snprintf(buf, PAGE_SIZE, "0x%08x\n", options);
4671         return l;
4672 }
4673 static DEVICE_ATTR_RO(options);
4674
4675 /* Support for tape stats */
4676
4677 /**
4678  * read_cnt_show - return read count - count of reads made from tape drive
4679  * @dev: struct device
4680  * @attr: attribute structure
4681  * @buf: buffer to return formatted data in
4682  */
4683 static ssize_t read_cnt_show(struct device *dev,
4684         struct device_attribute *attr, char *buf)
4685 {
4686         struct st_modedef *STm = dev_get_drvdata(dev);
4687
4688         return sprintf(buf, "%lld",
4689                        (long long)atomic64_read(&STm->tape->stats->read_cnt));
4690 }
4691 static DEVICE_ATTR_RO(read_cnt);
4692
4693 /**
4694  * read_byte_cnt_show - return read byte count - tape drives
4695  * may use blocks less than 512 bytes this gives the raw byte count of
4696  * of data read from the tape drive.
4697  * @dev: struct device
4698  * @attr: attribute structure
4699  * @buf: buffer to return formatted data in
4700  */
4701 static ssize_t read_byte_cnt_show(struct device *dev,
4702         struct device_attribute *attr, char *buf)
4703 {
4704         struct st_modedef *STm = dev_get_drvdata(dev);
4705
4706         return sprintf(buf, "%lld",
4707                        (long long)atomic64_read(&STm->tape->stats->read_byte_cnt));
4708 }
4709 static DEVICE_ATTR_RO(read_byte_cnt);
4710
4711 /**
4712  * read_ns_show - return read ns - overall time spent waiting on reads in ns.
4713  * @dev: struct device
4714  * @attr: attribute structure
4715  * @buf: buffer to return formatted data in
4716  */
4717 static ssize_t read_ns_show(struct device *dev,
4718         struct device_attribute *attr, char *buf)
4719 {
4720         struct st_modedef *STm = dev_get_drvdata(dev);
4721
4722         return sprintf(buf, "%lld",
4723                        (long long)atomic64_read(&STm->tape->stats->tot_read_time));
4724 }
4725 static DEVICE_ATTR_RO(read_ns);
4726
4727 /**
4728  * write_cnt_show - write count - number of user calls
4729  * to write(2) that have written data to tape.
4730  * @dev: struct device
4731  * @attr: attribute structure
4732  * @buf: buffer to return formatted data in
4733  */
4734 static ssize_t write_cnt_show(struct device *dev,
4735         struct device_attribute *attr, char *buf)
4736 {
4737         struct st_modedef *STm = dev_get_drvdata(dev);
4738
4739         return sprintf(buf, "%lld",
4740                        (long long)atomic64_read(&STm->tape->stats->write_cnt));
4741 }
4742 static DEVICE_ATTR_RO(write_cnt);
4743
4744 /**
4745  * write_byte_cnt_show - write byte count - raw count of
4746  * bytes written to tape.
4747  * @dev: struct device
4748  * @attr: attribute structure
4749  * @buf: buffer to return formatted data in
4750  */
4751 static ssize_t write_byte_cnt_show(struct device *dev,
4752         struct device_attribute *attr, char *buf)
4753 {
4754         struct st_modedef *STm = dev_get_drvdata(dev);
4755
4756         return sprintf(buf, "%lld",
4757                        (long long)atomic64_read(&STm->tape->stats->write_byte_cnt));
4758 }
4759 static DEVICE_ATTR_RO(write_byte_cnt);
4760
4761 /**
4762  * write_ns_show - write ns - number of nanoseconds waiting on write
4763  * requests to complete.
4764  * @dev: struct device
4765  * @attr: attribute structure
4766  * @buf: buffer to return formatted data in
4767  */
4768 static ssize_t write_ns_show(struct device *dev,
4769         struct device_attribute *attr, char *buf)
4770 {
4771         struct st_modedef *STm = dev_get_drvdata(dev);
4772
4773         return sprintf(buf, "%lld",
4774                        (long long)atomic64_read(&STm->tape->stats->tot_write_time));
4775 }
4776 static DEVICE_ATTR_RO(write_ns);
4777
4778 /**
4779  * in_flight_show - number of I/Os currently in flight -
4780  * in most cases this will be either 0 or 1. It may be higher if someone
4781  * has also issued other SCSI commands such as via an ioctl.
4782  * @dev: struct device
4783  * @attr: attribute structure
4784  * @buf: buffer to return formatted data in
4785  */
4786 static ssize_t in_flight_show(struct device *dev,
4787         struct device_attribute *attr, char *buf)
4788 {
4789         struct st_modedef *STm = dev_get_drvdata(dev);
4790
4791         return sprintf(buf, "%lld",
4792                        (long long)atomic64_read(&STm->tape->stats->in_flight));
4793 }
4794 static DEVICE_ATTR_RO(in_flight);
4795
4796 /**
4797  * io_ns_show - io wait ns - this is the number of ns spent
4798  * waiting on all I/O to complete. This includes tape movement commands
4799  * such as rewinding, seeking to end of file or tape, it also includes
4800  * read and write. To determine the time spent on tape movement
4801  * subtract the read and write ns from this value.
4802  * @dev: struct device
4803  * @attr: attribute structure
4804  * @buf: buffer to return formatted data in
4805  */
4806 static ssize_t io_ns_show(struct device *dev,
4807         struct device_attribute *attr, char *buf)
4808 {
4809         struct st_modedef *STm = dev_get_drvdata(dev);
4810
4811         return sprintf(buf, "%lld",
4812                        (long long)atomic64_read(&STm->tape->stats->tot_io_time));
4813 }
4814 static DEVICE_ATTR_RO(io_ns);
4815
4816 /**
4817  * other_cnt_show - other io count - this is the number of
4818  * I/O requests other than read and write requests.
4819  * Typically these are tape movement requests but will include driver
4820  * tape movement. This includes only requests issued by the st driver.
4821  * @dev: struct device
4822  * @attr: attribute structure
4823  * @buf: buffer to return formatted data in
4824  */
4825 static ssize_t other_cnt_show(struct device *dev,
4826         struct device_attribute *attr, char *buf)
4827 {
4828         struct st_modedef *STm = dev_get_drvdata(dev);
4829
4830         return sprintf(buf, "%lld",
4831                        (long long)atomic64_read(&STm->tape->stats->other_cnt));
4832 }
4833 static DEVICE_ATTR_RO(other_cnt);
4834
4835 /**
4836  * resid_cnt_show - A count of the number of times we get a residual
4837  * count - this should indicate someone issuing reads larger than the
4838  * block size on tape.
4839  * @dev: struct device
4840  * @attr: attribute structure
4841  * @buf: buffer to return formatted data in
4842  */
4843 static ssize_t resid_cnt_show(struct device *dev,
4844         struct device_attribute *attr, char *buf)
4845 {
4846         struct st_modedef *STm = dev_get_drvdata(dev);
4847
4848         return sprintf(buf, "%lld",
4849                        (long long)atomic64_read(&STm->tape->stats->resid_cnt));
4850 }
4851 static DEVICE_ATTR_RO(resid_cnt);
4852
4853 static struct attribute *st_dev_attrs[] = {
4854         &dev_attr_defined.attr,
4855         &dev_attr_default_blksize.attr,
4856         &dev_attr_default_density.attr,
4857         &dev_attr_default_compression.attr,
4858         &dev_attr_options.attr,
4859         NULL,
4860 };
4861
4862 static struct attribute *st_stats_attrs[] = {
4863         &dev_attr_read_cnt.attr,
4864         &dev_attr_read_byte_cnt.attr,
4865         &dev_attr_read_ns.attr,
4866         &dev_attr_write_cnt.attr,
4867         &dev_attr_write_byte_cnt.attr,
4868         &dev_attr_write_ns.attr,
4869         &dev_attr_in_flight.attr,
4870         &dev_attr_io_ns.attr,
4871         &dev_attr_other_cnt.attr,
4872         &dev_attr_resid_cnt.attr,
4873         NULL,
4874 };
4875
4876 static struct attribute_group stats_group = {
4877         .name = "stats",
4878         .attrs = st_stats_attrs,
4879 };
4880
4881 static struct attribute_group st_group = {
4882         .attrs = st_dev_attrs,
4883 };
4884
4885 static const struct attribute_group *st_dev_groups[] = {
4886         &st_group,
4887         &stats_group,
4888         NULL,
4889 };
4890
4891 /* The following functions may be useful for a larger audience. */
4892 static int sgl_map_user_pages(struct st_buffer *STbp,
4893                               const unsigned int max_pages, unsigned long uaddr,
4894                               size_t count, int rw)
4895 {
4896         unsigned long end = (uaddr + count + PAGE_SIZE - 1) >> PAGE_SHIFT;
4897         unsigned long start = uaddr >> PAGE_SHIFT;
4898         const int nr_pages = end - start;
4899         int res, i, j;
4900         struct page **pages;
4901         struct rq_map_data *mdata = &STbp->map_data;
4902
4903         /* User attempted Overflow! */
4904         if ((uaddr + count) < uaddr)
4905                 return -EINVAL;
4906
4907         /* Too big */
4908         if (nr_pages > max_pages)
4909                 return -ENOMEM;
4910
4911         /* Hmm? */
4912         if (count == 0)
4913                 return 0;
4914
4915         pages = kmalloc_array(max_pages, sizeof(*pages), GFP_KERNEL);
4916         if (pages == NULL)
4917                 return -ENOMEM;
4918
4919         /* Try to fault in all of the necessary pages */
4920         /* rw==READ means read from drive, write into memory area */
4921         res = get_user_pages_fast(uaddr, nr_pages, rw == READ, pages);
4922
4923         /* Errors and no page mapped should return here */
4924         if (res < nr_pages)
4925                 goto out_unmap;
4926
4927         for (i=0; i < nr_pages; i++) {
4928                 /* FIXME: flush superflous for rw==READ,
4929                  * probably wrong function for rw==WRITE
4930                  */
4931                 flush_dcache_page(pages[i]);
4932         }
4933
4934         mdata->offset = uaddr & ~PAGE_MASK;
4935         STbp->mapped_pages = pages;
4936
4937         return nr_pages;
4938  out_unmap:
4939         if (res > 0) {
4940                 for (j=0; j < res; j++)
4941                         put_page(pages[j]);
4942                 res = 0;
4943         }
4944         kfree(pages);
4945         return res;
4946 }
4947
4948
4949 /* And unmap them... */
4950 static int sgl_unmap_user_pages(struct st_buffer *STbp,
4951                                 const unsigned int nr_pages, int dirtied)
4952 {
4953         int i;
4954
4955         for (i=0; i < nr_pages; i++) {
4956                 struct page *page = STbp->mapped_pages[i];
4957
4958                 if (dirtied)
4959                         SetPageDirty(page);
4960                 /* FIXME: cache flush missing for rw==READ
4961                  * FIXME: call the correct reference counting function
4962                  */
4963                 put_page(page);
4964         }
4965         kfree(STbp->mapped_pages);
4966         STbp->mapped_pages = NULL;
4967
4968         return 0;
4969 }