drivers/scsi/sg.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  History:
   4  *  Started: Aug 9 by Lawrence Foard (entropy@world.std.com),
   5  *           to allow user process control of SCSI devices.
   6  *  Development Sponsored by Killy Corp. NY NY
   7  *
   8  * Original driver (sg.c):
   9  *        Copyright (C) 1992 Lawrence Foard
  10  * Version 2 and 3 extensions to driver:
  11  *        Copyright (C) 1998 - 2014 Douglas Gilbert
  12  */
  13
  14 static int sg_version_num = 30536;      /* 2 digits for each component */
  15 #define SG_VERSION_STR "3.5.36"
  16
  17 /*
  18  *  D. P. Gilbert (dgilbert@interlog.com), notes:
  19  *      - scsi logging is available via SCSI_LOG_TIMEOUT macros. First
  20  *        the kernel/module needs to be built with CONFIG_SCSI_LOGGING
  21  *        (otherwise the macros compile to empty statements).
  22  *
  23  */
  24 #include <linux/module.h>
  25
  26 #include <linux/fs.h>
  27 #include <linux/kernel.h>
  28 #include <linux/sched.h>
  29 #include <linux/string.h>
  30 #include <linux/mm.h>
  31 #include <linux/errno.h>
  32 #include <linux/mtio.h>
  33 #include <linux/ioctl.h>
  34 #include <linux/slab.h>
  35 #include <linux/fcntl.h>
  36 #include <linux/init.h>
  37 #include <linux/poll.h>
  38 #include <linux/moduleparam.h>
  39 #include <linux/cdev.h>
  40 #include <linux/idr.h>
  41 #include <linux/seq_file.h>
  42 #include <linux/blkdev.h>
  43 #include <linux/delay.h>
  44 #include <linux/blktrace_api.h>
  45 #include <linux/mutex.h>
  46 #include <linux/atomic.h>
  47 #include <linux/ratelimit.h>
  48 #include <linux/uio.h>
  49 #include <linux/cred.h> /* for sg_check_file_access() */
  50
  51 #include "scsi.h"
  52 #include <scsi/scsi_dbg.h>
  53 #include <scsi/scsi_host.h>
  54 #include <scsi/scsi_driver.h>
  55 #include <scsi/scsi_ioctl.h>
  56 #include <scsi/sg.h>
  57
  58 #include "scsi_logging.h"
  59
  60 #ifdef CONFIG_SCSI_PROC_FS
  61 #include <linux/proc_fs.h>
  62 static char *sg_version_date = "20140603";
  63
  64 static int sg_proc_init(void);
  65 #endif
  66
  67 #define SG_ALLOW_DIO_DEF 0
  68
  69 #define SG_MAX_DEVS 32768
  70
  71 /* SG_MAX_CDB_SIZE should be 260 (spc4r37 section 3.1.30) however the type
  72  * of sg_io_hdr::cmd_len can only represent 255. All SCSI commands greater
  73  * than 16 bytes are "variable length" whose length is a multiple of 4
  74  */
  75 #define SG_MAX_CDB_SIZE 252
  76
  77 #define SG_DEFAULT_TIMEOUT mult_frac(SG_DEFAULT_TIMEOUT_USER, HZ, USER_HZ)
  78
  79 int sg_big_buff = SG_DEF_RESERVED_SIZE;
  80 /* N.B. This variable is readable and writeable via
  81    /proc/scsi/sg/def_reserved_size . Each time sg_open() is called a buffer
  82    of this size (or less if there is not enough memory) will be reserved
  83    for use by this file descriptor. [Deprecated usage: this variable is also
  84    readable via /proc/sys/kernel/sg-big-buff if the sg driver is built into
  85    the kernel (i.e. it is not a module).] */
  86 static int def_reserved_size = -1;      /* picks up init parameter */
  87 static int sg_allow_dio = SG_ALLOW_DIO_DEF;
  88
  89 static int scatter_elem_sz = SG_SCATTER_SZ;
  90 static int scatter_elem_sz_prev = SG_SCATTER_SZ;
  91
  92 #define SG_SECTOR_SZ 512
  93
  94 static int sg_add_device(struct device *, struct class_interface *);
  95 static void sg_remove_device(struct device *, struct class_interface *);
  96
  97 static DEFINE_IDR(sg_index_idr);
  98 static DEFINE_RWLOCK(sg_index_lock);    /* Also used to lock
  99                                                            file descriptor list for device */
 100
 101 static struct class_interface sg_interface = {
 102         .add_dev        = sg_add_device,
 103         .remove_dev     = sg_remove_device,
 104 };
 105
 106 typedef struct sg_scatter_hold { /* holding area for scsi scatter gather info */
 107         unsigned short k_use_sg; /* Count of kernel scatter-gather pieces */
 108         unsigned sglist_len; /* size of malloc'd scatter-gather list ++ */
 109         unsigned bufflen;       /* Size of (aggregate) data buffer */
 110         struct page **pages;
 111         int page_order;
 112         char dio_in_use;        /* 0->indirect IO (or mmap), 1->dio */
 113         unsigned char cmd_opcode; /* first byte of command */
 114 } Sg_scatter_hold;
 115
 116 struct sg_device;               /* forward declarations */
 117 struct sg_fd;
 118
 119 typedef struct sg_request {     /* SG_MAX_QUEUE requests outstanding per file */
 120         struct list_head entry; /* list entry */
 121         struct sg_fd *parentfp; /* NULL -> not in use */
 122         Sg_scatter_hold data;   /* hold buffer, perhaps scatter list */
 123         sg_io_hdr_t header;     /* scsi command+info, see <scsi/sg.h> */
 124         unsigned char sense_b[SCSI_SENSE_BUFFERSIZE];
 125         char res_used;          /* 1 -> using reserve buffer, 0 -> not ... */
 126         char orphan;            /* 1 -> drop on sight, 0 -> normal */
 127         char sg_io_owned;       /* 1 -> packet belongs to SG_IO */
 128         /* done protected by rq_list_lock */
 129         char done;              /* 0->before bh, 1->before read, 2->read */
 130         struct request *rq;
 131         struct bio *bio;
 132         struct execute_work ew;
 133 } Sg_request;
 134
 135 typedef struct sg_fd {          /* holds the state of a file descriptor */
 136         struct list_head sfd_siblings;  /* protected by device's sfd_lock */
 137         struct sg_device *parentdp;     /* owning device */
 138         wait_queue_head_t read_wait;    /* queue read until command done */
 139         rwlock_t rq_list_lock;  /* protect access to list in req_arr */
 140         struct mutex f_mutex;   /* protect against changes in this fd */
 141         int timeout;            /* defaults to SG_DEFAULT_TIMEOUT      */
 142         int timeout_user;       /* defaults to SG_DEFAULT_TIMEOUT_USER */
 143         Sg_scatter_hold reserve;        /* buffer held for this file descriptor */
 144         struct list_head rq_list; /* head of request list */
 145         struct fasync_struct *async_qp; /* used by asynchronous notification */
 146         Sg_request req_arr[SG_MAX_QUEUE];       /* used as singly-linked list */
 147         char force_packid;      /* 1 -> pack_id input to read(), 0 -> ignored */
 148         char cmd_q;             /* 1 -> allow command queuing, 0 -> don't */
 149         unsigned char next_cmd_len; /* 0: automatic, >0: use on next write() */
 150         char keep_orphan;       /* 0 -> drop orphan (def), 1 -> keep for read() */
 151         char mmap_called;       /* 0 -> mmap() never called on this fd */
 152         char res_in_use;        /* 1 -> 'reserve' array in use */
 153         struct kref f_ref;
 154         struct execute_work ew;
 155 } Sg_fd;
 156
 157 typedef struct sg_device { /* holds the state of each scsi generic device */
 158         struct scsi_device *device;
 159         wait_queue_head_t open_wait;    /* queue open() when O_EXCL present */
 160         struct mutex open_rel_lock;     /* held when in open() or release() */
 161         int sg_tablesize;       /* adapter's max scatter-gather table size */
 162         u32 index;              /* device index number */
 163         struct list_head sfds;
 164         rwlock_t sfd_lock;      /* protect access to sfd list */
 165         atomic_t detaching;     /* 0->device usable, 1->device detaching */
 166         bool exclude;           /* 1->open(O_EXCL) succeeded and is active */
 167         int open_cnt;           /* count of opens (perhaps < num(sfds) ) */
 168         char sgdebug;           /* 0->off, 1->sense, 9->dump dev, 10-> all devs */
 169         struct gendisk *disk;
 170         struct cdev * cdev;     /* char_dev [sysfs: /sys/cdev/major/sg<n>] */
 171         struct kref d_ref;
 172 } Sg_device;
 173
 174 /* tasklet or soft irq callback */
 175 static void sg_rq_end_io(struct request *rq, blk_status_t status);
 176 static int sg_start_req(Sg_request *srp, unsigned char *cmd);
 177 static int sg_finish_rem_req(Sg_request * srp);
 178 static int sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size);
 179 static ssize_t sg_new_read(Sg_fd * sfp, char __user *buf, size_t count,
 180                            Sg_request * srp);
 181 static ssize_t sg_new_write(Sg_fd *sfp, struct file *file,
 182                         const char __user *buf, size_t count, int blocking,
 183                         int read_only, int sg_io_owned, Sg_request **o_srp);
 184 static int sg_common_write(Sg_fd * sfp, Sg_request * srp,
 185                            unsigned char *cmnd, int timeout, int blocking);
 186 static int sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer);
 187 static void sg_remove_scat(Sg_fd * sfp, Sg_scatter_hold * schp);
 188 static void sg_build_reserve(Sg_fd * sfp, int req_size);
 189 static void sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size);
 190 static void sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp);
 191 static Sg_fd *sg_add_sfp(Sg_device * sdp);
 192 static void sg_remove_sfp(struct kref *);
 193 static Sg_request *sg_get_rq_mark(Sg_fd * sfp, int pack_id, bool *busy);
 194 static Sg_request *sg_add_request(Sg_fd * sfp);
 195 static int sg_remove_request(Sg_fd * sfp, Sg_request * srp);
 196 static Sg_device *sg_get_dev(int dev);
 197 static void sg_device_destroy(struct kref *kref);
 198
 199 #define SZ_SG_HEADER sizeof(struct sg_header)
 200 #define SZ_SG_IO_HDR sizeof(sg_io_hdr_t)
 201 #define SZ_SG_IOVEC sizeof(sg_iovec_t)
 202 #define SZ_SG_REQ_INFO sizeof(sg_req_info_t)
 203
 204 #define sg_printk(prefix, sdp, fmt, a...) \
 205         sdev_prefix_printk(prefix, (sdp)->device,               \
 206                            (sdp)->disk->disk_name, fmt, ##a)
 207
 208 /*
 209  * The SCSI interfaces that use read() and write() as an asynchronous variant of
 210  * ioctl(..., SG_IO, ...) are fundamentally unsafe, since there are lots of ways
 211  * to trigger read() and write() calls from various contexts with elevated
 212  * privileges. This can lead to kernel memory corruption (e.g. if these
 213  * interfaces are called through splice()) and privilege escalation inside
 214  * userspace (e.g. if a process with access to such a device passes a file
 215  * descriptor to a SUID binary as stdin/stdout/stderr).
 216  *
 217  * This function provides protection for the legacy API by restricting the
 218  * calling context.
 219  */
 220 static int sg_check_file_access(struct file *filp, const char *caller)
 221 {
 222         if (filp->f_cred != current_real_cred()) {
 223                 pr_err_once("%s: process %d (%s) changed security contexts after opening file descriptor, this is not allowed.\n",
 224                         caller, task_tgid_vnr(current), current->comm);
 225                 return -EPERM;
 226         }
 227         if (uaccess_kernel()) {
 228                 pr_err_once("%s: process %d (%s) called from kernel context, this is not allowed.\n",
 229                         caller, task_tgid_vnr(current), current->comm);
 230                 return -EACCES;
 231         }
 232         return 0;
 233 }
 234
 235 static int sg_allow_access(struct file *filp, unsigned char *cmd)
 236 {
 237         struct sg_fd *sfp = filp->private_data;
 238
 239         if (sfp->parentdp->device->type == TYPE_SCANNER)
 240                 return 0;
 241
 242         return blk_verify_command(cmd, filp->f_mode);
 243 }
 244
 245 static int
 246 open_wait(Sg_device *sdp, int flags)
 247 {
 248         int retval = 0;
 249
 250         if (flags & O_EXCL) {
 251                 while (sdp->open_cnt > 0) {
 252                         mutex_unlock(&sdp->open_rel_lock);
 253                         retval = wait_event_interruptible(sdp->open_wait,
 254                                         (atomic_read(&sdp->detaching) ||
 255                                          !sdp->open_cnt));
 256                         mutex_lock(&sdp->open_rel_lock);
 257
 258                         if (retval) /* -ERESTARTSYS */
 259                                 return retval;
 260                         if (atomic_read(&sdp->detaching))
 261                                 return -ENODEV;
 262                 }
 263         } else {
 264                 while (sdp->exclude) {
 265                         mutex_unlock(&sdp->open_rel_lock);
 266                         retval = wait_event_interruptible(sdp->open_wait,
 267                                         (atomic_read(&sdp->detaching) ||
 268                                          !sdp->exclude));
 269                         mutex_lock(&sdp->open_rel_lock);
 270
 271                         if (retval) /* -ERESTARTSYS */
 272                                 return retval;
 273                         if (atomic_read(&sdp->detaching))
 274                                 return -ENODEV;
 275                 }
 276         }
 277
 278         return retval;
 279 }
 280
 281 /* Returns 0 on success, else a negated errno value */
 282 static int
 283 sg_open(struct inode *inode, struct file *filp)
 284 {
 285         int dev = iminor(inode);
 286         int flags = filp->f_flags;
 287         struct request_queue *q;
 288         Sg_device *sdp;
 289         Sg_fd *sfp;
 290         int retval;
 291
 292         nonseekable_open(inode, filp);
 293         if ((flags & O_EXCL) && (O_RDONLY == (flags & O_ACCMODE)))
 294                 return -EPERM; /* Can't lock it with read only access */
 295         sdp = sg_get_dev(dev);
 296         if (IS_ERR(sdp))
 297                 return PTR_ERR(sdp);
 298
 299         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
 300                                       "sg_open: flags=0x%x\n", flags));
 301
 302         /* This driver's module count bumped by fops_get in <linux/fs.h> */
 303         /* Prevent the device driver from vanishing while we sleep */
 304         retval = scsi_device_get(sdp->device);
 305         if (retval)
 306                 goto sg_put;
 307
 308         retval = scsi_autopm_get_device(sdp->device);
 309         if (retval)
 310                 goto sdp_put;
 311
 312         /* scsi_block_when_processing_errors() may block so bypass
 313          * check if O_NONBLOCK. Permits SCSI commands to be issued
 314          * during error recovery. Tread carefully. */
 315         if (!((flags & O_NONBLOCK) ||
 316               scsi_block_when_processing_errors(sdp->device))) {
 317                 retval = -ENXIO;
 318                 /* we are in error recovery for this device */
 319                 goto error_out;
 320         }
 321
 322         mutex_lock(&sdp->open_rel_lock);
 323         if (flags & O_NONBLOCK) {
 324                 if (flags & O_EXCL) {
 325                         if (sdp->open_cnt > 0) {
 326                                 retval = -EBUSY;
 327                                 goto error_mutex_locked;
 328                         }
 329                 } else {
 330                         if (sdp->exclude) {
 331                                 retval = -EBUSY;
 332                                 goto error_mutex_locked;
 333                         }
 334                 }
 335         } else {
 336                 retval = open_wait(sdp, flags);
 337                 if (retval) /* -ERESTARTSYS or -ENODEV */
 338                         goto error_mutex_locked;
 339         }
 340
 341         /* N.B. at this point we are holding the open_rel_lock */
 342         if (flags & O_EXCL)
 343                 sdp->exclude = true;
 344
 345         if (sdp->open_cnt < 1) {  /* no existing opens */
 346                 sdp->sgdebug = 0;
 347                 q = sdp->device->request_queue;
 348                 sdp->sg_tablesize = queue_max_segments(q);
 349         }
 350         sfp = sg_add_sfp(sdp);
 351         if (IS_ERR(sfp)) {
 352                 retval = PTR_ERR(sfp);
 353                 goto out_undo;
 354         }
 355
 356         filp->private_data = sfp;
 357         sdp->open_cnt++;
 358         mutex_unlock(&sdp->open_rel_lock);
 359
 360         retval = 0;
 361 sg_put:
 362         kref_put(&sdp->d_ref, sg_device_destroy);
 363         return retval;
 364
 365 out_undo:
 366         if (flags & O_EXCL) {
 367                 sdp->exclude = false;   /* undo if error */
 368                 wake_up_interruptible(&sdp->open_wait);
 369         }
 370 error_mutex_locked:
 371         mutex_unlock(&sdp->open_rel_lock);
 372 error_out:
 373         scsi_autopm_put_device(sdp->device);
 374 sdp_put:
 375         scsi_device_put(sdp->device);
 376         goto sg_put;
 377 }
 378
 379 /* Release resources associated with a successful sg_open()
 380  * Returns 0 on success, else a negated errno value */
 381 static int
 382 sg_release(struct inode *inode, struct file *filp)
 383 {
 384         Sg_device *sdp;
 385         Sg_fd *sfp;
 386
 387         if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
 388                 return -ENXIO;
 389         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp, "sg_release\n"));
 390
 391         mutex_lock(&sdp->open_rel_lock);
 392         scsi_autopm_put_device(sdp->device);
 393         kref_put(&sfp->f_ref, sg_remove_sfp);
 394         sdp->open_cnt--;
 395
 396         /* possibly many open()s waiting on exlude clearing, start many;
 397          * only open(O_EXCL)s wait on 0==open_cnt so only start one */
 398         if (sdp->exclude) {
 399                 sdp->exclude = false;
 400                 wake_up_interruptible_all(&sdp->open_wait);
 401         } else if (0 == sdp->open_cnt) {
 402                 wake_up_interruptible(&sdp->open_wait);
 403         }
 404         mutex_unlock(&sdp->open_rel_lock);
 405         return 0;
 406 }
 407
 408 static int get_sg_io_pack_id(int *pack_id, void __user *buf, size_t count)
 409 {
 410         struct sg_header __user *old_hdr = buf;
 411         int reply_len;
 412
 413         if (count >= SZ_SG_HEADER) {
 414                 /* negative reply_len means v3 format, otherwise v1/v2 */
 415                 if (get_user(reply_len, &old_hdr->reply_len))
 416                         return -EFAULT;
 417
 418                 if (reply_len >= 0)
 419                         return get_user(*pack_id, &old_hdr->pack_id);
 420
 421                 if (in_compat_syscall() &&
 422                     count >= sizeof(struct compat_sg_io_hdr)) {
 423                         struct compat_sg_io_hdr __user *hp = buf;
 424
 425                         return get_user(*pack_id, &hp->pack_id);
 426                 }
 427
 428                 if (count >= sizeof(struct sg_io_hdr)) {
 429                         struct sg_io_hdr __user *hp = buf;
 430
 431                         return get_user(*pack_id, &hp->pack_id);
 432                 }
 433         }
 434
 435         /* no valid header was passed, so ignore the pack_id */
 436         *pack_id = -1;
 437         return 0;
 438 }
 439
 440 static ssize_t
 441 sg_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
 442 {
 443         Sg_device *sdp;
 444         Sg_fd *sfp;
 445         Sg_request *srp;
 446         int req_pack_id = -1;
 447         bool busy;
 448         sg_io_hdr_t *hp;
 449         struct sg_header *old_hdr;
 450         int retval;
 451
 452         /*
 453          * This could cause a response to be stranded. Close the associated
 454          * file descriptor to free up any resources being held.
 455          */
 456         retval = sg_check_file_access(filp, __func__);
 457         if (retval)
 458                 return retval;
 459
 460         if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
 461                 return -ENXIO;
 462         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
 463                                       "sg_read: count=%d\n", (int) count));
 464
 465         if (sfp->force_packid)
 466                 retval = get_sg_io_pack_id(&req_pack_id, buf, count);
 467         if (retval)
 468                 return retval;
 469
 470         srp = sg_get_rq_mark(sfp, req_pack_id, &busy);
 471         if (!srp) {             /* now wait on packet to arrive */
 472                 if (filp->f_flags & O_NONBLOCK)
 473                         return -EAGAIN;
 474                 retval = wait_event_interruptible(sfp->read_wait,
 475                         ((srp = sg_get_rq_mark(sfp, req_pack_id, &busy)) ||
 476                         (!busy && atomic_read(&sdp->detaching))));
 477                 if (!srp)
 478                         /* signal or detaching */
 479                         return retval ? retval : -ENODEV;
 480         }
 481         if (srp->header.interface_id != '\0')
 482                 return sg_new_read(sfp, buf, count, srp);
 483
 484         hp = &srp->header;
 485         old_hdr = kzalloc(SZ_SG_HEADER, GFP_KERNEL);
 486         if (!old_hdr)
 487                 return -ENOMEM;
 488
 489         old_hdr->reply_len = (int) hp->timeout;
 490         old_hdr->pack_len = old_hdr->reply_len; /* old, strange behaviour */
 491         old_hdr->pack_id = hp->pack_id;
 492         old_hdr->twelve_byte =
 493             ((srp->data.cmd_opcode >= 0xc0) && (12 == hp->cmd_len)) ? 1 : 0;
 494         old_hdr->target_status = hp->masked_status;
 495         old_hdr->host_status = hp->host_status;
 496         old_hdr->driver_status = hp->driver_status;
 497         if ((CHECK_CONDITION & hp->masked_status) ||
 498             (DRIVER_SENSE & hp->driver_status))
 499                 memcpy(old_hdr->sense_buffer, srp->sense_b,
 500                        sizeof (old_hdr->sense_buffer));
 501         switch (hp->host_status) {
 502         /* This setup of 'result' is for backward compatibility and is best
 503            ignored by the user who should use target, host + driver status */
 504         case DID_OK:
 505         case DID_PASSTHROUGH:
 506         case DID_SOFT_ERROR:
 507                 old_hdr->result = 0;
 508                 break;
 509         case DID_NO_CONNECT:
 510         case DID_BUS_BUSY:
 511         case DID_TIME_OUT:
 512                 old_hdr->result = EBUSY;
 513                 break;
 514         case DID_BAD_TARGET:
 515         case DID_ABORT:
 516         case DID_PARITY:
 517         case DID_RESET:
 518         case DID_BAD_INTR:
 519                 old_hdr->result = EIO;
 520                 break;
 521         case DID_ERROR:
 522                 old_hdr->result = (srp->sense_b[0] == 0 &&
 523                                   hp->masked_status == GOOD) ? 0 : EIO;
 524                 break;
 525         default:
 526                 old_hdr->result = EIO;
 527                 break;
 528         }
 529
 530         /* Now copy the result back to the user buffer.  */
 531         if (count >= SZ_SG_HEADER) {
 532                 if (copy_to_user(buf, old_hdr, SZ_SG_HEADER)) {
 533                         retval = -EFAULT;
 534                         goto free_old_hdr;
 535                 }
 536                 buf += SZ_SG_HEADER;
 537                 if (count > old_hdr->reply_len)
 538                         count = old_hdr->reply_len;
 539                 if (count > SZ_SG_HEADER) {
 540                         if (sg_read_oxfer(srp, buf, count - SZ_SG_HEADER)) {
 541                                 retval = -EFAULT;
 542                                 goto free_old_hdr;
 543                         }
 544                 }
 545         } else
 546                 count = (old_hdr->result == 0) ? 0 : -EIO;
 547         sg_finish_rem_req(srp);
 548         sg_remove_request(sfp, srp);
 549         retval = count;
 550 free_old_hdr:
 551         kfree(old_hdr);
 552         return retval;
 553 }
 554
 555 static ssize_t
 556 sg_new_read(Sg_fd * sfp, char __user *buf, size_t count, Sg_request * srp)
 557 {
 558         sg_io_hdr_t *hp = &srp->header;
 559         int err = 0, err2;
 560         int len;
 561
 562         if (in_compat_syscall()) {
 563                 if (count < sizeof(struct compat_sg_io_hdr)) {
 564                         err = -EINVAL;
 565                         goto err_out;
 566                 }
 567         } else if (count < SZ_SG_IO_HDR) {
 568                 err = -EINVAL;
 569                 goto err_out;
 570         }
 571         hp->sb_len_wr = 0;
 572         if ((hp->mx_sb_len > 0) && hp->sbp) {
 573                 if ((CHECK_CONDITION & hp->masked_status) ||
 574                     (DRIVER_SENSE & hp->driver_status)) {
 575                         int sb_len = SCSI_SENSE_BUFFERSIZE;
 576                         sb_len = (hp->mx_sb_len > sb_len) ? sb_len : hp->mx_sb_len;
 577                         len = 8 + (int) srp->sense_b[7];        /* Additional sense length field */
 578                         len = (len > sb_len) ? sb_len : len;
 579                         if (copy_to_user(hp->sbp, srp->sense_b, len)) {
 580                                 err = -EFAULT;
 581                                 goto err_out;
 582                         }
 583                         hp->sb_len_wr = len;
 584                 }
 585         }
 586         if (hp->masked_status || hp->host_status || hp->driver_status)
 587                 hp->info |= SG_INFO_CHECK;
 588         err = put_sg_io_hdr(hp, buf);
 589 err_out:
 590         err2 = sg_finish_rem_req(srp);
 591         sg_remove_request(sfp, srp);
 592         return err ? : err2 ? : count;
 593 }
 594
 595 static ssize_t
 596 sg_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
 597 {
 598         int mxsize, cmd_size, k;
 599         int input_size, blocking;
 600         unsigned char opcode;
 601         Sg_device *sdp;
 602         Sg_fd *sfp;
 603         Sg_request *srp;
 604         struct sg_header old_hdr;
 605         sg_io_hdr_t *hp;
 606         unsigned char cmnd[SG_MAX_CDB_SIZE];
 607         int retval;
 608
 609         retval = sg_check_file_access(filp, __func__);
 610         if (retval)
 611                 return retval;
 612
 613         if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
 614                 return -ENXIO;
 615         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
 616                                       "sg_write: count=%d\n", (int) count));
 617         if (atomic_read(&sdp->detaching))
 618                 return -ENODEV;
 619         if (!((filp->f_flags & O_NONBLOCK) ||
 620               scsi_block_when_processing_errors(sdp->device)))
 621                 return -ENXIO;
 622
 623         if (count < SZ_SG_HEADER)
 624                 return -EIO;
 625         if (copy_from_user(&old_hdr, buf, SZ_SG_HEADER))
 626                 return -EFAULT;
 627         blocking = !(filp->f_flags & O_NONBLOCK);
 628         if (old_hdr.reply_len < 0)
 629                 return sg_new_write(sfp, filp, buf, count,
 630                                     blocking, 0, 0, NULL);
 631         if (count < (SZ_SG_HEADER + 6))
 632                 return -EIO;    /* The minimum scsi command length is 6 bytes. */
 633
 634         buf += SZ_SG_HEADER;
 635         if (get_user(opcode, buf))
 636                 return -EFAULT;
 637
 638         if (!(srp = sg_add_request(sfp))) {
 639                 SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sdp,
 640                                               "sg_write: queue full\n"));
 641                 return -EDOM;
 642         }
 643         mutex_lock(&sfp->f_mutex);
 644         if (sfp->next_cmd_len > 0) {
 645                 cmd_size = sfp->next_cmd_len;
 646                 sfp->next_cmd_len = 0;  /* reset so only this write() effected */
 647         } else {
 648                 cmd_size = COMMAND_SIZE(opcode);        /* based on SCSI command group */
 649                 if ((opcode >= 0xc0) && old_hdr.twelve_byte)
 650                         cmd_size = 12;
 651         }
 652         mutex_unlock(&sfp->f_mutex);
 653         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sdp,
 654                 "sg_write:   scsi opcode=0x%02x, cmd_size=%d\n", (int) opcode, cmd_size));
 655 /* Determine buffer size.  */
 656         input_size = count - cmd_size;
 657         mxsize = (input_size > old_hdr.reply_len) ? input_size : old_hdr.reply_len;
 658         mxsize -= SZ_SG_HEADER;
 659         input_size -= SZ_SG_HEADER;
 660         if (input_size < 0) {
 661                 sg_remove_request(sfp, srp);
 662                 return -EIO;    /* User did not pass enough bytes for this command. */
 663         }
 664         hp = &srp->header;
 665         hp->interface_id = '\0';        /* indicator of old interface tunnelled */
 666         hp->cmd_len = (unsigned char) cmd_size;
 667         hp->iovec_count = 0;
 668         hp->mx_sb_len = 0;
 669         if (input_size > 0)
 670                 hp->dxfer_direction = (old_hdr.reply_len > SZ_SG_HEADER) ?
 671                     SG_DXFER_TO_FROM_DEV : SG_DXFER_TO_DEV;
 672         else
 673                 hp->dxfer_direction = (mxsize > 0) ? SG_DXFER_FROM_DEV : SG_DXFER_NONE;
 674         hp->dxfer_len = mxsize;
 675         if ((hp->dxfer_direction == SG_DXFER_TO_DEV) ||
 676             (hp->dxfer_direction == SG_DXFER_TO_FROM_DEV))
 677                 hp->dxferp = (char __user *)buf + cmd_size;
 678         else
 679                 hp->dxferp = NULL;
 680         hp->sbp = NULL;
 681         hp->timeout = old_hdr.reply_len;        /* structure abuse ... */
 682         hp->flags = input_size; /* structure abuse ... */
 683         hp->pack_id = old_hdr.pack_id;
 684         hp->usr_ptr = NULL;
 685         if (copy_from_user(cmnd, buf, cmd_size)) {
 686                 sg_remove_request(sfp, srp);
 687                 return -EFAULT;
 688         }
 689         /*
 690          * SG_DXFER_TO_FROM_DEV is functionally equivalent to SG_DXFER_FROM_DEV,
 691          * but is is possible that the app intended SG_DXFER_TO_DEV, because there
 692          * is a non-zero input_size, so emit a warning.
 693          */
 694         if (hp->dxfer_direction == SG_DXFER_TO_FROM_DEV) {
 695                 printk_ratelimited(KERN_WARNING
 696                                    "sg_write: data in/out %d/%d bytes "
 697                                    "for SCSI command 0x%x-- guessing "
 698                                    "data in;\n   program %s not setting "
 699                                    "count and/or reply_len properly\n",
 700                                    old_hdr.reply_len - (int)SZ_SG_HEADER,
 701                                    input_size, (unsigned int) cmnd[0],
 702                                    current->comm);
 703         }
 704         k = sg_common_write(sfp, srp, cmnd, sfp->timeout, blocking);
 705         return (k < 0) ? k : count;
 706 }
 707
 708 static ssize_t
 709 sg_new_write(Sg_fd *sfp, struct file *file, const char __user *buf,
 710                  size_t count, int blocking, int read_only, int sg_io_owned,
 711                  Sg_request **o_srp)
 712 {
 713         int k;
 714         Sg_request *srp;
 715         sg_io_hdr_t *hp;
 716         unsigned char cmnd[SG_MAX_CDB_SIZE];
 717         int timeout;
 718         unsigned long ul_timeout;
 719
 720         if (count < SZ_SG_IO_HDR)
 721                 return -EINVAL;
 722
 723         sfp->cmd_q = 1; /* when sg_io_hdr seen, set command queuing on */
 724         if (!(srp = sg_add_request(sfp))) {
 725                 SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sfp->parentdp,
 726                                               "sg_new_write: queue full\n"));
 727                 return -EDOM;
 728         }
 729         srp->sg_io_owned = sg_io_owned;
 730         hp = &srp->header;
 731         if (get_sg_io_hdr(hp, buf)) {
 732                 sg_remove_request(sfp, srp);
 733                 return -EFAULT;
 734         }
 735         if (hp->interface_id != 'S') {
 736                 sg_remove_request(sfp, srp);
 737                 return -ENOSYS;
 738         }
 739         if (hp->flags & SG_FLAG_MMAP_IO) {
 740                 if (hp->dxfer_len > sfp->reserve.bufflen) {
 741                         sg_remove_request(sfp, srp);
 742                         return -ENOMEM; /* MMAP_IO size must fit in reserve buffer */
 743                 }
 744                 if (hp->flags & SG_FLAG_DIRECT_IO) {
 745                         sg_remove_request(sfp, srp);
 746                         return -EINVAL; /* either MMAP_IO or DIRECT_IO (not both) */
 747                 }
 748                 if (sfp->res_in_use) {
 749                         sg_remove_request(sfp, srp);
 750                         return -EBUSY;  /* reserve buffer already being used */
 751                 }
 752         }
 753         ul_timeout = msecs_to_jiffies(srp->header.timeout);
 754         timeout = (ul_timeout < INT_MAX) ? ul_timeout : INT_MAX;
 755         if ((!hp->cmdp) || (hp->cmd_len < 6) || (hp->cmd_len > sizeof (cmnd))) {
 756                 sg_remove_request(sfp, srp);
 757                 return -EMSGSIZE;
 758         }
 759         if (copy_from_user(cmnd, hp->cmdp, hp->cmd_len)) {
 760                 sg_remove_request(sfp, srp);
 761                 return -EFAULT;
 762         }
 763         if (read_only && sg_allow_access(file, cmnd)) {
 764                 sg_remove_request(sfp, srp);
 765                 return -EPERM;
 766         }
 767         k = sg_common_write(sfp, srp, cmnd, timeout, blocking);
 768         if (k < 0)
 769                 return k;
 770         if (o_srp)
 771                 *o_srp = srp;
 772         return count;
 773 }
 774
 775 static int
 776 sg_common_write(Sg_fd * sfp, Sg_request * srp,
 777                 unsigned char *cmnd, int timeout, int blocking)
 778 {
 779         int k, at_head;
 780         Sg_device *sdp = sfp->parentdp;
 781         sg_io_hdr_t *hp = &srp->header;
 782
 783         srp->data.cmd_opcode = cmnd[0]; /* hold opcode of command */
 784         hp->status = 0;
 785         hp->masked_status = 0;
 786         hp->msg_status = 0;
 787         hp->info = 0;
 788         hp->host_status = 0;
 789         hp->driver_status = 0;
 790         hp->resid = 0;
 791         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
 792                         "sg_common_write:  scsi opcode=0x%02x, cmd_size=%d\n",
 793                         (int) cmnd[0], (int) hp->cmd_len));
 794
 795         if (hp->dxfer_len >= SZ_256M) {
 796                 sg_remove_request(sfp, srp);
 797                 return -EINVAL;
 798         }
 799
 800         k = sg_start_req(srp, cmnd);
 801         if (k) {
 802                 SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sfp->parentdp,
 803                         "sg_common_write: start_req err=%d\n", k));
 804                 sg_finish_rem_req(srp);
 805                 sg_remove_request(sfp, srp);
 806                 return k;       /* probably out of space --> ENOMEM */
 807         }
 808         if (atomic_read(&sdp->detaching)) {
 809                 if (srp->bio) {
 810                         scsi_req_free_cmd(scsi_req(srp->rq));
 811                         blk_put_request(srp->rq);
 812                         srp->rq = NULL;
 813                 }
 814
 815                 sg_finish_rem_req(srp);
 816                 sg_remove_request(sfp, srp);
 817                 return -ENODEV;
 818         }
 819
 820         hp->duration = jiffies_to_msecs(jiffies);
 821         if (hp->interface_id != '\0' && /* v3 (or later) interface */
 822             (SG_FLAG_Q_AT_TAIL & hp->flags))
 823                 at_head = 0;
 824         else
 825                 at_head = 1;
 826
 827         srp->rq->timeout = timeout;
 828         kref_get(&sfp->f_ref); /* sg_rq_end_io() does kref_put(). */
 829         blk_execute_rq_nowait(sdp->device->request_queue, sdp->disk,
 830                               srp->rq, at_head, sg_rq_end_io);
 831         return 0;
 832 }
 833
 834 static int srp_done(Sg_fd *sfp, Sg_request *srp)
 835 {
 836         unsigned long flags;
 837         int ret;
 838
 839         read_lock_irqsave(&sfp->rq_list_lock, flags);
 840         ret = srp->done;
 841         read_unlock_irqrestore(&sfp->rq_list_lock, flags);
 842         return ret;
 843 }
 844
 845 static int max_sectors_bytes(struct request_queue *q)
 846 {
 847         unsigned int max_sectors = queue_max_sectors(q);
 848
 849         max_sectors = min_t(unsigned int, max_sectors, INT_MAX >> 9);
 850
 851         return max_sectors << 9;
 852 }
 853
 854 static void
 855 sg_fill_request_table(Sg_fd *sfp, sg_req_info_t *rinfo)
 856 {
 857         Sg_request *srp;
 858         int val;
 859         unsigned int ms;
 860
 861         val = 0;
 862         list_for_each_entry(srp, &sfp->rq_list, entry) {
 863                 if (val >= SG_MAX_QUEUE)
 864                         break;
 865                 rinfo[val].req_state = srp->done + 1;
 866                 rinfo[val].problem =
 867                         srp->header.masked_status &
 868                         srp->header.host_status &
 869                         srp->header.driver_status;
 870                 if (srp->done)
 871                         rinfo[val].duration =
 872                                 srp->header.duration;
 873                 else {
 874                         ms = jiffies_to_msecs(jiffies);
 875                         rinfo[val].duration =
 876                                 (ms > srp->header.duration) ?
 877                                 (ms - srp->header.duration) : 0;
 878                 }
 879                 rinfo[val].orphan = srp->orphan;
 880                 rinfo[val].sg_io_owned = srp->sg_io_owned;
 881                 rinfo[val].pack_id = srp->header.pack_id;
 882                 rinfo[val].usr_ptr = srp->header.usr_ptr;
 883                 val++;
 884         }
 885 }
 886
 887 #ifdef CONFIG_COMPAT
 888 struct compat_sg_req_info { /* used by SG_GET_REQUEST_TABLE ioctl() */
 889         char req_state;
 890         char orphan;
 891         char sg_io_owned;
 892         char problem;
 893         int pack_id;
 894         compat_uptr_t usr_ptr;
 895         unsigned int duration;
 896         int unused;
 897 };
 898
 899 static int put_compat_request_table(struct compat_sg_req_info __user *o,
 900                                     struct sg_req_info *rinfo)
 901 {
 902         int i;
 903         for (i = 0; i < SG_MAX_QUEUE; i++) {
 904                 if (copy_to_user(o + i, rinfo + i, offsetof(sg_req_info_t, usr_ptr)) ||
 905                     put_user((uintptr_t)rinfo[i].usr_ptr, &o[i].usr_ptr) ||
 906                     put_user(rinfo[i].duration, &o[i].duration) ||
 907                     put_user(rinfo[i].unused, &o[i].unused))
 908                         return -EFAULT;
 909         }
 910         return 0;
 911 }
 912 #endif
 913
 914 static long
 915 sg_ioctl_common(struct file *filp, Sg_device *sdp, Sg_fd *sfp,
 916                 unsigned int cmd_in, void __user *p)
 917 {
 918         int __user *ip = p;
 919         int result, val, read_only;
 920         Sg_request *srp;
 921         unsigned long iflags;
 922
 923         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
 924                                    "sg_ioctl: cmd=0x%x\n", (int) cmd_in));
 925         read_only = (O_RDWR != (filp->f_flags & O_ACCMODE));
 926
 927         switch (cmd_in) {
 928         case SG_IO:
 929                 if (atomic_read(&sdp->detaching))
 930                         return -ENODEV;
 931                 if (!scsi_block_when_processing_errors(sdp->device))
 932                         return -ENXIO;
 933                 result = sg_new_write(sfp, filp, p, SZ_SG_IO_HDR,
 934                                  1, read_only, 1, &srp);
 935                 if (result < 0)
 936                         return result;
 937                 result = wait_event_interruptible(sfp->read_wait,
 938                         srp_done(sfp, srp));
 939                 write_lock_irq(&sfp->rq_list_lock);
 940                 if (srp->done) {
 941                         srp->done = 2;
 942                         write_unlock_irq(&sfp->rq_list_lock);
 943                         result = sg_new_read(sfp, p, SZ_SG_IO_HDR, srp);
 944                         return (result < 0) ? result : 0;
 945                 }
 946                 srp->orphan = 1;
 947                 write_unlock_irq(&sfp->rq_list_lock);
 948                 return result;  /* -ERESTARTSYS because signal hit process */
 949         case SG_SET_TIMEOUT:
 950                 result = get_user(val, ip);
 951                 if (result)
 952                         return result;
 953                 if (val < 0)
 954                         return -EIO;
 955                 if (val >= mult_frac((s64)INT_MAX, USER_HZ, HZ))
 956                         val = min_t(s64, mult_frac((s64)INT_MAX, USER_HZ, HZ),
 957                                     INT_MAX);
 958                 sfp->timeout_user = val;
 959                 sfp->timeout = mult_frac(val, HZ, USER_HZ);
 960
 961                 return 0;
 962         case SG_GET_TIMEOUT:    /* N.B. User receives timeout as return value */
 963                                 /* strange ..., for backward compatibility */
 964                 return sfp->timeout_user;
 965         case SG_SET_FORCE_LOW_DMA:
 966                 /*
 967                  * N.B. This ioctl never worked properly, but failed to
 968                  * return an error value. So returning '0' to keep compability
 969                  * with legacy applications.
 970                  */
 971                 return 0;
 972         case SG_GET_LOW_DMA:
 973                 return put_user((int) sdp->device->host->unchecked_isa_dma, ip);
 974         case SG_GET_SCSI_ID:
 975                 {
 976                         sg_scsi_id_t v;
 977
 978                         if (atomic_read(&sdp->detaching))
 979                                 return -ENODEV;
 980                         memset(&v, 0, sizeof(v));
 981                         v.host_no = sdp->device->host->host_no;
 982                         v.channel = sdp->device->channel;
 983                         v.scsi_id = sdp->device->id;
 984                         v.lun = sdp->device->lun;
 985                         v.scsi_type = sdp->device->type;
 986                         v.h_cmd_per_lun = sdp->device->host->cmd_per_lun;
 987                         v.d_queue_depth = sdp->device->queue_depth;
 988                         if (copy_to_user(p, &v, sizeof(sg_scsi_id_t)))
 989                                 return -EFAULT;
 990                         return 0;
 991                 }
 992         case SG_SET_FORCE_PACK_ID:
 993                 result = get_user(val, ip);
 994                 if (result)
 995                         return result;
 996                 sfp->force_packid = val ? 1 : 0;
 997                 return 0;
 998         case SG_GET_PACK_ID:
 999                 read_lock_irqsave(&sfp->rq_list_lock, iflags);
1000                 list_for_each_entry(srp, &sfp->rq_list, entry) {
1001                         if ((1 == srp->done) && (!srp->sg_io_owned)) {
1002                                 read_unlock_irqrestore(&sfp->rq_list_lock,
1003                                                        iflags);
1004                                 return put_user(srp->header.pack_id, ip);
1005                         }
1006                 }
1007                 read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1008                 return put_user(-1, ip);
1009         case SG_GET_NUM_WAITING:
1010                 read_lock_irqsave(&sfp->rq_list_lock, iflags);
1011                 val = 0;
1012                 list_for_each_entry(srp, &sfp->rq_list, entry) {
1013                         if ((1 == srp->done) && (!srp->sg_io_owned))
1014                                 ++val;
1015                 }
1016                 read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1017                 return put_user(val, ip);
1018         case SG_GET_SG_TABLESIZE:
1019                 return put_user(sdp->sg_tablesize, ip);
1020         case SG_SET_RESERVED_SIZE:
1021                 result = get_user(val, ip);
1022                 if (result)
1023                         return result;
1024                 if (val < 0)
1025                         return -EINVAL;
1026                 val = min_t(int, val,
1027                             max_sectors_bytes(sdp->device->request_queue));
1028                 mutex_lock(&sfp->f_mutex);
1029                 if (val != sfp->reserve.bufflen) {
1030                         if (sfp->mmap_called ||
1031                             sfp->res_in_use) {
1032                                 mutex_unlock(&sfp->f_mutex);
1033                                 return -EBUSY;
1034                         }
1035
1036                         sg_remove_scat(sfp, &sfp->reserve);
1037                         sg_build_reserve(sfp, val);
1038                 }
1039                 mutex_unlock(&sfp->f_mutex);
1040                 return 0;
1041         case SG_GET_RESERVED_SIZE:
1042                 val = min_t(int, sfp->reserve.bufflen,
1043                             max_sectors_bytes(sdp->device->request_queue));
1044                 return put_user(val, ip);
1045         case SG_SET_COMMAND_Q:
1046                 result = get_user(val, ip);
1047                 if (result)
1048                         return result;
1049                 sfp->cmd_q = val ? 1 : 0;
1050                 return 0;
1051         case SG_GET_COMMAND_Q:
1052                 return put_user((int) sfp->cmd_q, ip);
1053         case SG_SET_KEEP_ORPHAN:
1054                 result = get_user(val, ip);
1055                 if (result)
1056                         return result;
1057                 sfp->keep_orphan = val;
1058                 return 0;
1059         case SG_GET_KEEP_ORPHAN:
1060                 return put_user((int) sfp->keep_orphan, ip);
1061         case SG_NEXT_CMD_LEN:
1062                 result = get_user(val, ip);
1063                 if (result)
1064                         return result;
1065                 if (val > SG_MAX_CDB_SIZE)
1066                         return -ENOMEM;
1067                 sfp->next_cmd_len = (val > 0) ? val : 0;
1068                 return 0;
1069         case SG_GET_VERSION_NUM:
1070                 return put_user(sg_version_num, ip);
1071         case SG_GET_ACCESS_COUNT:
1072                 /* faked - we don't have a real access count anymore */
1073                 val = (sdp->device ? 1 : 0);
1074                 return put_user(val, ip);
1075         case SG_GET_REQUEST_TABLE:
1076                 {
1077                         sg_req_info_t *rinfo;
1078
1079                         rinfo = kcalloc(SG_MAX_QUEUE, SZ_SG_REQ_INFO,
1080                                         GFP_KERNEL);
1081                         if (!rinfo)
1082                                 return -ENOMEM;
1083                         read_lock_irqsave(&sfp->rq_list_lock, iflags);
1084                         sg_fill_request_table(sfp, rinfo);
1085                         read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1086         #ifdef CONFIG_COMPAT
1087                         if (in_compat_syscall())
1088                                 result = put_compat_request_table(p, rinfo);
1089                         else
1090         #endif
1091                                 result = copy_to_user(p, rinfo,
1092                                                       SZ_SG_REQ_INFO * SG_MAX_QUEUE);
1093                         result = result ? -EFAULT : 0;
1094                         kfree(rinfo);
1095                         return result;
1096                 }
1097         case SG_EMULATED_HOST:
1098                 if (atomic_read(&sdp->detaching))
1099                         return -ENODEV;
1100                 return put_user(sdp->device->host->hostt->emulated, ip);
1101         case SCSI_IOCTL_SEND_COMMAND:
1102                 if (atomic_read(&sdp->detaching))
1103                         return -ENODEV;
1104                 return sg_scsi_ioctl(sdp->device->request_queue, NULL, filp->f_mode, p);
1105         case SG_SET_DEBUG:
1106                 result = get_user(val, ip);
1107                 if (result)
1108                         return result;
1109                 sdp->sgdebug = (char) val;
1110                 return 0;
1111         case BLKSECTGET:
1112                 return put_user(max_sectors_bytes(sdp->device->request_queue),
1113                                 ip);
1114         case BLKTRACESETUP:
1115                 return blk_trace_setup(sdp->device->request_queue,
1116                                        sdp->disk->disk_name,
1117                                        MKDEV(SCSI_GENERIC_MAJOR, sdp->index),
1118                                        NULL, p);
1119         case BLKTRACESTART:
1120                 return blk_trace_startstop(sdp->device->request_queue, 1);
1121         case BLKTRACESTOP:
1122                 return blk_trace_startstop(sdp->device->request_queue, 0);
1123         case BLKTRACETEARDOWN:
1124                 return blk_trace_remove(sdp->device->request_queue);
1125         case SCSI_IOCTL_GET_IDLUN:
1126         case SCSI_IOCTL_GET_BUS_NUMBER:
1127         case SCSI_IOCTL_PROBE_HOST:
1128         case SG_GET_TRANSFORM:
1129         case SG_SCSI_RESET:
1130                 if (atomic_read(&sdp->detaching))
1131                         return -ENODEV;
1132                 break;
1133         default:
1134                 if (read_only)
1135                         return -EPERM;  /* don't know so take safe approach */
1136                 break;
1137         }
1138
1139         result = scsi_ioctl_block_when_processing_errors(sdp->device,
1140                         cmd_in, filp->f_flags & O_NDELAY);
1141         if (result)
1142                 return result;
1143
1144         return -ENOIOCTLCMD;
1145 }
1146
1147 static long
1148 sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
1149 {
1150         void __user *p = (void __user *)arg;
1151         Sg_device *sdp;
1152         Sg_fd *sfp;
1153         int ret;
1154
1155         if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1156                 return -ENXIO;
1157
1158         ret = sg_ioctl_common(filp, sdp, sfp, cmd_in, p);
1159         if (ret != -ENOIOCTLCMD)
1160                 return ret;
1161
1162         return scsi_ioctl(sdp->device, cmd_in, p);
1163 }
1164
1165 #ifdef CONFIG_COMPAT
1166 static long sg_compat_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
1167 {
1168         void __user *p = compat_ptr(arg);
1169         Sg_device *sdp;
1170         Sg_fd *sfp;
1171         int ret;
1172
1173         if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1174                 return -ENXIO;
1175
1176         ret = sg_ioctl_common(filp, sdp, sfp, cmd_in, p);
1177         if (ret != -ENOIOCTLCMD)
1178                 return ret;
1179
1180         return scsi_compat_ioctl(sdp->device, cmd_in, p);
1181 }
1182 #endif
1183
1184 static __poll_t
1185 sg_poll(struct file *filp, poll_table * wait)
1186 {
1187         __poll_t res = 0;
1188         Sg_device *sdp;
1189         Sg_fd *sfp;
1190         Sg_request *srp;
1191         int count = 0;
1192         unsigned long iflags;
1193
1194         sfp = filp->private_data;
1195         if (!sfp)
1196                 return EPOLLERR;
1197         sdp = sfp->parentdp;
1198         if (!sdp)
1199                 return EPOLLERR;
1200         poll_wait(filp, &sfp->read_wait, wait);
1201         read_lock_irqsave(&sfp->rq_list_lock, iflags);
1202         list_for_each_entry(srp, &sfp->rq_list, entry) {
1203                 /* if any read waiting, flag it */
1204                 if ((0 == res) && (1 == srp->done) && (!srp->sg_io_owned))
1205                         res = EPOLLIN | EPOLLRDNORM;
1206                 ++count;
1207         }
1208         read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1209
1210         if (atomic_read(&sdp->detaching))
1211                 res |= EPOLLHUP;
1212         else if (!sfp->cmd_q) {
1213                 if (0 == count)
1214                         res |= EPOLLOUT | EPOLLWRNORM;
1215         } else if (count < SG_MAX_QUEUE)
1216                 res |= EPOLLOUT | EPOLLWRNORM;
1217         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
1218                                       "sg_poll: res=0x%x\n", (__force u32) res));
1219         return res;
1220 }
1221
1222 static int
1223 sg_fasync(int fd, struct file *filp, int mode)
1224 {
1225         Sg_device *sdp;
1226         Sg_fd *sfp;
1227
1228         if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1229                 return -ENXIO;
1230         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
1231                                       "sg_fasync: mode=%d\n", mode));
1232
1233         return fasync_helper(fd, filp, mode, &sfp->async_qp);
1234 }
1235
1236 static vm_fault_t
1237 sg_vma_fault(struct vm_fault *vmf)
1238 {
1239         struct vm_area_struct *vma = vmf->vma;
1240         Sg_fd *sfp;
1241         unsigned long offset, len, sa;
1242         Sg_scatter_hold *rsv_schp;
1243         int k, length;
1244
1245         if ((NULL == vma) || (!(sfp = (Sg_fd *) vma->vm_private_data)))
1246                 return VM_FAULT_SIGBUS;
1247         rsv_schp = &sfp->reserve;
1248         offset = vmf->pgoff << PAGE_SHIFT;
1249         if (offset >= rsv_schp->bufflen)
1250                 return VM_FAULT_SIGBUS;
1251         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sfp->parentdp,
1252                                       "sg_vma_fault: offset=%lu, scatg=%d\n",
1253                                       offset, rsv_schp->k_use_sg));
1254         sa = vma->vm_start;
1255         length = 1 << (PAGE_SHIFT + rsv_schp->page_order);
1256         for (k = 0; k < rsv_schp->k_use_sg && sa < vma->vm_end; k++) {
1257                 len = vma->vm_end - sa;
1258                 len = (len < length) ? len : length;
1259                 if (offset < len) {
1260                         struct page *page = nth_page(rsv_schp->pages[k],
1261                                                      offset >> PAGE_SHIFT);
1262                         get_page(page); /* increment page count */
1263                         vmf->page = page;
1264                         return 0; /* success */
1265                 }
1266                 sa += len;
1267                 offset -= len;
1268         }
1269
1270         return VM_FAULT_SIGBUS;
1271 }
1272
1273 static const struct vm_operations_struct sg_mmap_vm_ops = {
1274         .fault = sg_vma_fault,
1275 };
1276
1277 static int
1278 sg_mmap(struct file *filp, struct vm_area_struct *vma)
1279 {
1280         Sg_fd *sfp;
1281         unsigned long req_sz, len, sa;
1282         Sg_scatter_hold *rsv_schp;
1283         int k, length;
1284         int ret = 0;
1285
1286         if ((!filp) || (!vma) || (!(sfp = (Sg_fd *) filp->private_data)))
1287                 return -ENXIO;
1288         req_sz = vma->vm_end - vma->vm_start;
1289         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sfp->parentdp,
1290                                       "sg_mmap starting, vm_start=%p, len=%d\n",
1291                                       (void *) vma->vm_start, (int) req_sz));
1292         if (vma->vm_pgoff)
1293                 return -EINVAL; /* want no offset */
1294         rsv_schp = &sfp->reserve;
1295         mutex_lock(&sfp->f_mutex);
1296         if (req_sz > rsv_schp->bufflen) {
1297                 ret = -ENOMEM;  /* cannot map more than reserved buffer */
1298                 goto out;
1299         }
1300
1301         sa = vma->vm_start;
1302         length = 1 << (PAGE_SHIFT + rsv_schp->page_order);
1303         for (k = 0; k < rsv_schp->k_use_sg && sa < vma->vm_end; k++) {
1304                 len = vma->vm_end - sa;
1305                 len = (len < length) ? len : length;
1306                 sa += len;
1307         }
1308
1309         sfp->mmap_called = 1;
1310         vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP;
1311         vma->vm_private_data = sfp;
1312         vma->vm_ops = &sg_mmap_vm_ops;
1313 out:
1314         mutex_unlock(&sfp->f_mutex);
1315         return ret;
1316 }
1317
1318 static void
1319 sg_rq_end_io_usercontext(struct work_struct *work)
1320 {
1321         struct sg_request *srp = container_of(work, struct sg_request, ew.work);
1322         struct sg_fd *sfp = srp->parentfp;
1323
1324         sg_finish_rem_req(srp);
1325         sg_remove_request(sfp, srp);
1326         kref_put(&sfp->f_ref, sg_remove_sfp);
1327 }
1328
1329 /*
1330  * This function is a "bottom half" handler that is called by the mid
1331  * level when a command is completed (or has failed).
1332  */
1333 static void
1334 sg_rq_end_io(struct request *rq, blk_status_t status)
1335 {
1336         struct sg_request *srp = rq->end_io_data;
1337         struct scsi_request *req = scsi_req(rq);
1338         Sg_device *sdp;
1339         Sg_fd *sfp;
1340         unsigned long iflags;
1341         unsigned int ms;
1342         char *sense;
1343         int result, resid, done = 1;
1344
1345         if (WARN_ON(srp->done != 0))
1346                 return;
1347
1348         sfp = srp->parentfp;
1349         if (WARN_ON(sfp == NULL))
1350                 return;
1351
1352         sdp = sfp->parentdp;
1353         if (unlikely(atomic_read(&sdp->detaching)))
1354                 pr_info("%s: device detaching\n", __func__);
1355
1356         sense = req->sense;
1357         result = req->result;
1358         resid = req->resid_len;
1359
1360         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sdp,
1361                                       "sg_cmd_done: pack_id=%d, res=0x%x\n",
1362                                       srp->header.pack_id, result));
1363         srp->header.resid = resid;
1364         ms = jiffies_to_msecs(jiffies);
1365         srp->header.duration = (ms > srp->header.duration) ?
1366                                 (ms - srp->header.duration) : 0;
1367         if (0 != result) {
1368                 struct scsi_sense_hdr sshdr;
1369
1370                 srp->header.status = 0xff & result;
1371                 srp->header.masked_status = status_byte(result);
1372                 srp->header.msg_status = msg_byte(result);
1373                 srp->header.host_status = host_byte(result);
1374                 srp->header.driver_status = driver_byte(result);
1375                 if ((sdp->sgdebug > 0) &&
1376                     ((CHECK_CONDITION == srp->header.masked_status) ||
1377                      (COMMAND_TERMINATED == srp->header.masked_status)))
1378                         __scsi_print_sense(sdp->device, __func__, sense,
1379                                            SCSI_SENSE_BUFFERSIZE);
1380
1381                 /* Following if statement is a patch supplied by Eric Youngdale */
1382                 if (driver_byte(result) != 0
1383                     && scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, &sshdr)
1384                     && !scsi_sense_is_deferred(&sshdr)
1385                     && sshdr.sense_key == UNIT_ATTENTION
1386                     && sdp->device->removable) {
1387                         /* Detected possible disc change. Set the bit - this */
1388                         /* may be used if there are filesystems using this device */
1389                         sdp->device->changed = 1;
1390                 }
1391         }
1392
1393         if (req->sense_len)
1394                 memcpy(srp->sense_b, req->sense, SCSI_SENSE_BUFFERSIZE);
1395
1396         /* Rely on write phase to clean out srp status values, so no "else" */
1397
1398         /*
1399          * Free the request as soon as it is complete so that its resources
1400          * can be reused without waiting for userspace to read() the
1401          * result.  But keep the associated bio (if any) around until
1402          * blk_rq_unmap_user() can be called from user context.
1403          */
1404         srp->rq = NULL;
1405         scsi_req_free_cmd(scsi_req(rq));
1406         blk_put_request(rq);
1407
1408         write_lock_irqsave(&sfp->rq_list_lock, iflags);
1409         if (unlikely(srp->orphan)) {
1410                 if (sfp->keep_orphan)
1411                         srp->sg_io_owned = 0;
1412                 else
1413                         done = 0;
1414         }
1415         srp->done = done;
1416         write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1417
1418         if (likely(done)) {
1419                 /* Now wake up any sg_read() that is waiting for this
1420                  * packet.
1421                  */
1422                 wake_up_interruptible(&sfp->read_wait);
1423                 kill_fasync(&sfp->async_qp, SIGPOLL, POLL_IN);
1424                 kref_put(&sfp->f_ref, sg_remove_sfp);
1425         } else {
1426                 INIT_WORK(&srp->ew.work, sg_rq_end_io_usercontext);
1427                 schedule_work(&srp->ew.work);
1428         }
1429 }
1430
1431 static const struct file_operations sg_fops = {
1432         .owner = THIS_MODULE,
1433         .read = sg_read,
1434         .write = sg_write,
1435         .poll = sg_poll,
1436         .unlocked_ioctl = sg_ioctl,
1437 #ifdef CONFIG_COMPAT
1438         .compat_ioctl = sg_compat_ioctl,
1439 #endif
1440         .open = sg_open,
1441         .mmap = sg_mmap,
1442         .release = sg_release,
1443         .fasync = sg_fasync,
1444         .llseek = no_llseek,
1445 };
1446
1447 static struct class *sg_sysfs_class;
1448
1449 static int sg_sysfs_valid = 0;
1450
1451 static Sg_device *
1452 sg_alloc(struct gendisk *disk, struct scsi_device *scsidp)
1453 {
1454         struct request_queue *q = scsidp->request_queue;
1455         Sg_device *sdp;
1456         unsigned long iflags;
1457         int error;
1458         u32 k;
1459
1460         sdp = kzalloc(sizeof(Sg_device), GFP_KERNEL);
1461         if (!sdp) {
1462                 sdev_printk(KERN_WARNING, scsidp, "%s: kmalloc Sg_device "
1463                             "failure\n", __func__);
1464                 return ERR_PTR(-ENOMEM);
1465         }
1466
1467         idr_preload(GFP_KERNEL);
1468         write_lock_irqsave(&sg_index_lock, iflags);
1469
1470         error = idr_alloc(&sg_index_idr, sdp, 0, SG_MAX_DEVS, GFP_NOWAIT);
1471         if (error < 0) {
1472                 if (error == -ENOSPC) {
1473                         sdev_printk(KERN_WARNING, scsidp,
1474                                     "Unable to attach sg device type=%d, minor number exceeds %d\n",
1475                                     scsidp->type, SG_MAX_DEVS - 1);
1476                         error = -ENODEV;
1477                 } else {
1478                         sdev_printk(KERN_WARNING, scsidp, "%s: idr "
1479                                     "allocation Sg_device failure: %d\n",
1480                                     __func__, error);
1481                 }
1482                 goto out_unlock;
1483         }
1484         k = error;
1485
1486         SCSI_LOG_TIMEOUT(3, sdev_printk(KERN_INFO, scsidp,
1487                                         "sg_alloc: dev=%d \n", k));
1488         sprintf(disk->disk_name, "sg%d", k);
1489         disk->first_minor = k;
1490         sdp->disk = disk;
1491         sdp->device = scsidp;
1492         mutex_init(&sdp->open_rel_lock);
1493         INIT_LIST_HEAD(&sdp->sfds);
1494         init_waitqueue_head(&sdp->open_wait);
1495         atomic_set(&sdp->detaching, 0);
1496         rwlock_init(&sdp->sfd_lock);
1497         sdp->sg_tablesize = queue_max_segments(q);
1498         sdp->index = k;
1499         kref_init(&sdp->d_ref);
1500         error = 0;
1501
1502 out_unlock:
1503         write_unlock_irqrestore(&sg_index_lock, iflags);
1504         idr_preload_end();
1505
1506         if (error) {
1507                 kfree(sdp);
1508                 return ERR_PTR(error);
1509         }
1510         return sdp;
1511 }
1512
1513 static int
1514 sg_add_device(struct device *cl_dev, struct class_interface *cl_intf)
1515 {
1516         struct scsi_device *scsidp = to_scsi_device(cl_dev->parent);
1517         struct gendisk *disk;
1518         Sg_device *sdp = NULL;
1519         struct cdev * cdev = NULL;
1520         int error;
1521         unsigned long iflags;
1522
1523         disk = alloc_disk(1);
1524         if (!disk) {
1525                 pr_warn("%s: alloc_disk failed\n", __func__);
1526                 return -ENOMEM;
1527         }
1528         disk->major = SCSI_GENERIC_MAJOR;
1529
1530         error = -ENOMEM;
1531         cdev = cdev_alloc();
1532         if (!cdev) {
1533                 pr_warn("%s: cdev_alloc failed\n", __func__);
1534                 goto out;
1535         }
1536         cdev->owner = THIS_MODULE;
1537         cdev->ops = &sg_fops;
1538
1539         sdp = sg_alloc(disk, scsidp);
1540         if (IS_ERR(sdp)) {
1541                 pr_warn("%s: sg_alloc failed\n", __func__);
1542                 error = PTR_ERR(sdp);
1543                 goto out;
1544         }
1545
1546         error = cdev_add(cdev, MKDEV(SCSI_GENERIC_MAJOR, sdp->index), 1);
1547         if (error)
1548                 goto cdev_add_err;
1549
1550         sdp->cdev = cdev;
1551         if (sg_sysfs_valid) {
1552                 struct device *sg_class_member;
1553
1554                 sg_class_member = device_create(sg_sysfs_class, cl_dev->parent,
1555                                                 MKDEV(SCSI_GENERIC_MAJOR,
1556                                                       sdp->index),
1557                                                 sdp, "%s", disk->disk_name);
1558                 if (IS_ERR(sg_class_member)) {
1559                         pr_err("%s: device_create failed\n", __func__);
1560                         error = PTR_ERR(sg_class_member);
1561                         goto cdev_add_err;
1562                 }
1563                 error = sysfs_create_link(&scsidp->sdev_gendev.kobj,
1564                                           &sg_class_member->kobj, "generic");
1565                 if (error)
1566                         pr_err("%s: unable to make symlink 'generic' back "
1567                                "to sg%d\n", __func__, sdp->index);
1568         } else
1569                 pr_warn("%s: sg_sys Invalid\n", __func__);
1570
1571         sdev_printk(KERN_NOTICE, scsidp, "Attached scsi generic sg%d "
1572                     "type %d\n", sdp->index, scsidp->type);
1573
1574         dev_set_drvdata(cl_dev, sdp);
1575
1576         return 0;
1577
1578 cdev_add_err:
1579         write_lock_irqsave(&sg_index_lock, iflags);
1580         idr_remove(&sg_index_idr, sdp->index);
1581         write_unlock_irqrestore(&sg_index_lock, iflags);
1582         kfree(sdp);
1583
1584 out:
1585         put_disk(disk);
1586         if (cdev)
1587                 cdev_del(cdev);
1588         return error;
1589 }
1590
1591 static void
1592 sg_device_destroy(struct kref *kref)
1593 {
1594         struct sg_device *sdp = container_of(kref, struct sg_device, d_ref);
1595         unsigned long flags;
1596
1597         /* CAUTION!  Note that the device can still be found via idr_find()
1598          * even though the refcount is 0.  Therefore, do idr_remove() BEFORE
1599          * any other cleanup.
1600          */
1601
1602         write_lock_irqsave(&sg_index_lock, flags);
1603         idr_remove(&sg_index_idr, sdp->index);
1604         write_unlock_irqrestore(&sg_index_lock, flags);
1605
1606         SCSI_LOG_TIMEOUT(3,
1607                 sg_printk(KERN_INFO, sdp, "sg_device_destroy\n"));
1608
1609         put_disk(sdp->disk);
1610         kfree(sdp);
1611 }
1612
1613 static void
1614 sg_remove_device(struct device *cl_dev, struct class_interface *cl_intf)
1615 {
1616         struct scsi_device *scsidp = to_scsi_device(cl_dev->parent);
1617         Sg_device *sdp = dev_get_drvdata(cl_dev);
1618         unsigned long iflags;
1619         Sg_fd *sfp;
1620         int val;
1621
1622         if (!sdp)
1623                 return;
1624         /* want sdp->detaching non-zero as soon as possible */
1625         val = atomic_inc_return(&sdp->detaching);
1626         if (val > 1)
1627                 return; /* only want to do following once per device */
1628
1629         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
1630                                       "%s\n", __func__));
1631
1632         read_lock_irqsave(&sdp->sfd_lock, iflags);
1633         list_for_each_entry(sfp, &sdp->sfds, sfd_siblings) {
1634                 wake_up_interruptible_all(&sfp->read_wait);
1635                 kill_fasync(&sfp->async_qp, SIGPOLL, POLL_HUP);
1636         }
1637         wake_up_interruptible_all(&sdp->open_wait);
1638         read_unlock_irqrestore(&sdp->sfd_lock, iflags);
1639
1640         sysfs_remove_link(&scsidp->sdev_gendev.kobj, "generic");
1641         device_destroy(sg_sysfs_class, MKDEV(SCSI_GENERIC_MAJOR, sdp->index));
1642         cdev_del(sdp->cdev);
1643         sdp->cdev = NULL;
1644
1645         kref_put(&sdp->d_ref, sg_device_destroy);
1646 }
1647
1648 module_param_named(scatter_elem_sz, scatter_elem_sz, int, S_IRUGO | S_IWUSR);
1649 module_param_named(def_reserved_size, def_reserved_size, int,
1650                    S_IRUGO | S_IWUSR);
1651 module_param_named(allow_dio, sg_allow_dio, int, S_IRUGO | S_IWUSR);
1652
1653 MODULE_AUTHOR("Douglas Gilbert");
1654 MODULE_DESCRIPTION("SCSI generic (sg) driver");
1655 MODULE_LICENSE("GPL");
1656 MODULE_VERSION(SG_VERSION_STR);
1657 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_GENERIC_MAJOR);
1658
1659 MODULE_PARM_DESC(scatter_elem_sz, "scatter gather element "
1660                 "size (default: max(SG_SCATTER_SZ, PAGE_SIZE))");
1661 MODULE_PARM_DESC(def_reserved_size, "size of buffer reserved for each fd");
1662 MODULE_PARM_DESC(allow_dio, "allow direct I/O (default: 0 (disallow))");
1663
1664 static int __init
1665 init_sg(void)
1666 {
1667         int rc;
1668
1669         if (scatter_elem_sz < PAGE_SIZE) {
1670                 scatter_elem_sz = PAGE_SIZE;
1671                 scatter_elem_sz_prev = scatter_elem_sz;
1672         }
1673         if (def_reserved_size >= 0)
1674                 sg_big_buff = def_reserved_size;
1675         else
1676                 def_reserved_size = sg_big_buff;
1677
1678         rc = register_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
1679                                     SG_MAX_DEVS, "sg");
1680         if (rc)
1681                 return rc;
1682         sg_sysfs_class = class_create(THIS_MODULE, "scsi_generic");
1683         if ( IS_ERR(sg_sysfs_class) ) {
1684                 rc = PTR_ERR(sg_sysfs_class);
1685                 goto err_out;
1686         }
1687         sg_sysfs_valid = 1;
1688         rc = scsi_register_interface(&sg_interface);
1689         if (0 == rc) {
1690 #ifdef CONFIG_SCSI_PROC_FS
1691                 sg_proc_init();
1692 #endif                          /* CONFIG_SCSI_PROC_FS */
1693                 return 0;
1694         }
1695         class_destroy(sg_sysfs_class);
1696 err_out:
1697         unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0), SG_MAX_DEVS);
1698         return rc;
1699 }
1700
1701 static void __exit
1702 exit_sg(void)
1703 {
1704 #ifdef CONFIG_SCSI_PROC_FS
1705         remove_proc_subtree("scsi/sg", NULL);
1706 #endif                          /* CONFIG_SCSI_PROC_FS */
1707         scsi_unregister_interface(&sg_interface);
1708         class_destroy(sg_sysfs_class);
1709         sg_sysfs_valid = 0;
1710         unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
1711                                  SG_MAX_DEVS);
1712         idr_destroy(&sg_index_idr);
1713 }
1714
1715 static int
1716 sg_start_req(Sg_request *srp, unsigned char *cmd)
1717 {
1718         int res;
1719         struct request *rq;
1720         struct scsi_request *req;
1721         Sg_fd *sfp = srp->parentfp;
1722         sg_io_hdr_t *hp = &srp->header;
1723         int dxfer_len = (int) hp->dxfer_len;
1724         int dxfer_dir = hp->dxfer_direction;
1725         unsigned int iov_count = hp->iovec_count;
1726         Sg_scatter_hold *req_schp = &srp->data;
1727         Sg_scatter_hold *rsv_schp = &sfp->reserve;
1728         struct request_queue *q = sfp->parentdp->device->request_queue;
1729         struct rq_map_data *md, map_data;
1730         int rw = hp->dxfer_direction == SG_DXFER_TO_DEV ? WRITE : READ;
1731         unsigned char *long_cmdp = NULL;
1732
1733         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1734                                       "sg_start_req: dxfer_len=%d\n",
1735                                       dxfer_len));
1736
1737         if (hp->cmd_len > BLK_MAX_CDB) {
1738                 long_cmdp = kzalloc(hp->cmd_len, GFP_KERNEL);
1739                 if (!long_cmdp)
1740                         return -ENOMEM;
1741         }
1742
1743         /*
1744          * NOTE
1745          *
1746          * With scsi-mq enabled, there are a fixed number of preallocated
1747          * requests equal in number to shost->can_queue.  If all of the
1748          * preallocated requests are already in use, then blk_get_request()
1749          * will sleep until an active command completes, freeing up a request.
1750          * Although waiting in an asynchronous interface is less than ideal, we
1751          * do not want to use BLK_MQ_REQ_NOWAIT here because userspace might
1752          * not expect an EWOULDBLOCK from this condition.
1753          */
1754         rq = blk_get_request(q, hp->dxfer_direction == SG_DXFER_TO_DEV ?
1755                         REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, 0);
1756         if (IS_ERR(rq)) {
1757                 kfree(long_cmdp);
1758                 return PTR_ERR(rq);
1759         }
1760         req = scsi_req(rq);
1761
1762         if (hp->cmd_len > BLK_MAX_CDB)
1763                 req->cmd = long_cmdp;
1764         memcpy(req->cmd, cmd, hp->cmd_len);
1765         req->cmd_len = hp->cmd_len;
1766
1767         srp->rq = rq;
1768         rq->end_io_data = srp;
1769         req->retries = SG_DEFAULT_RETRIES;
1770
1771         if ((dxfer_len <= 0) || (dxfer_dir == SG_DXFER_NONE))
1772                 return 0;
1773
1774         if (sg_allow_dio && hp->flags & SG_FLAG_DIRECT_IO &&
1775             dxfer_dir != SG_DXFER_UNKNOWN && !iov_count &&
1776             !sfp->parentdp->device->host->unchecked_isa_dma &&
1777             blk_rq_aligned(q, (unsigned long)hp->dxferp, dxfer_len))
1778                 md = NULL;
1779         else
1780                 md = &map_data;
1781
1782         if (md) {
1783                 mutex_lock(&sfp->f_mutex);
1784                 if (dxfer_len <= rsv_schp->bufflen &&
1785                     !sfp->res_in_use) {
1786                         sfp->res_in_use = 1;
1787                         sg_link_reserve(sfp, srp, dxfer_len);
1788                 } else if (hp->flags & SG_FLAG_MMAP_IO) {
1789                         res = -EBUSY; /* sfp->res_in_use == 1 */
1790                         if (dxfer_len > rsv_schp->bufflen)
1791                                 res = -ENOMEM;
1792                         mutex_unlock(&sfp->f_mutex);
1793                         return res;
1794                 } else {
1795                         res = sg_build_indirect(req_schp, sfp, dxfer_len);
1796                         if (res) {
1797                                 mutex_unlock(&sfp->f_mutex);
1798                                 return res;
1799                         }
1800                 }
1801                 mutex_unlock(&sfp->f_mutex);
1802
1803                 md->pages = req_schp->pages;
1804                 md->page_order = req_schp->page_order;
1805                 md->nr_entries = req_schp->k_use_sg;
1806                 md->offset = 0;
1807                 md->null_mapped = hp->dxferp ? 0 : 1;
1808                 if (dxfer_dir == SG_DXFER_TO_FROM_DEV)
1809                         md->from_user = 1;
1810                 else
1811                         md->from_user = 0;
1812         }
1813
1814         if (iov_count) {
1815                 struct iovec *iov = NULL;
1816                 struct iov_iter i;
1817
1818                 res = import_iovec(rw, hp->dxferp, iov_count, 0, &iov, &i);
1819                 if (res < 0)
1820                         return res;
1821
1822                 iov_iter_truncate(&i, hp->dxfer_len);
1823                 if (!iov_iter_count(&i)) {
1824                         kfree(iov);
1825                         return -EINVAL;
1826                 }
1827
1828                 res = blk_rq_map_user_iov(q, rq, md, &i, GFP_ATOMIC);
1829                 kfree(iov);
1830         } else
1831                 res = blk_rq_map_user(q, rq, md, hp->dxferp,
1832                                       hp->dxfer_len, GFP_ATOMIC);
1833
1834         if (!res) {
1835                 srp->bio = rq->bio;
1836
1837                 if (!md) {
1838                         req_schp->dio_in_use = 1;
1839                         hp->info |= SG_INFO_DIRECT_IO;
1840                 }
1841         }
1842         return res;
1843 }
1844
1845 static int
1846 sg_finish_rem_req(Sg_request *srp)
1847 {
1848         int ret = 0;
1849
1850         Sg_fd *sfp = srp->parentfp;
1851         Sg_scatter_hold *req_schp = &srp->data;
1852
1853         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1854                                       "sg_finish_rem_req: res_used=%d\n",
1855                                       (int) srp->res_used));
1856         if (srp->bio)
1857                 ret = blk_rq_unmap_user(srp->bio);
1858
1859         if (srp->rq) {
1860                 scsi_req_free_cmd(scsi_req(srp->rq));
1861                 blk_put_request(srp->rq);
1862         }
1863
1864         if (srp->res_used)
1865                 sg_unlink_reserve(sfp, srp);
1866         else
1867                 sg_remove_scat(sfp, req_schp);
1868
1869         return ret;
1870 }
1871
1872 static int
1873 sg_build_sgat(Sg_scatter_hold * schp, const Sg_fd * sfp, int tablesize)
1874 {
1875         int sg_bufflen = tablesize * sizeof(struct page *);
1876         gfp_t gfp_flags = GFP_ATOMIC | __GFP_NOWARN;
1877
1878         schp->pages = kzalloc(sg_bufflen, gfp_flags);
1879         if (!schp->pages)
1880                 return -ENOMEM;
1881         schp->sglist_len = sg_bufflen;
1882         return tablesize;       /* number of scat_gath elements allocated */
1883 }
1884
1885 static int
1886 sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size)
1887 {
1888         int ret_sz = 0, i, k, rem_sz, num, mx_sc_elems;
1889         int sg_tablesize = sfp->parentdp->sg_tablesize;
1890         int blk_size = buff_size, order;
1891         gfp_t gfp_mask = GFP_ATOMIC | __GFP_COMP | __GFP_NOWARN | __GFP_ZERO;
1892         struct sg_device *sdp = sfp->parentdp;
1893
1894         if (blk_size < 0)
1895                 return -EFAULT;
1896         if (0 == blk_size)
1897                 ++blk_size;     /* don't know why */
1898         /* round request up to next highest SG_SECTOR_SZ byte boundary */
1899         blk_size = ALIGN(blk_size, SG_SECTOR_SZ);
1900         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1901                 "sg_build_indirect: buff_size=%d, blk_size=%d\n",
1902                 buff_size, blk_size));
1903
1904         /* N.B. ret_sz carried into this block ... */
1905         mx_sc_elems = sg_build_sgat(schp, sfp, sg_tablesize);
1906         if (mx_sc_elems < 0)
1907                 return mx_sc_elems;     /* most likely -ENOMEM */
1908
1909         num = scatter_elem_sz;
1910         if (unlikely(num != scatter_elem_sz_prev)) {
1911                 if (num < PAGE_SIZE) {
1912                         scatter_elem_sz = PAGE_SIZE;
1913                         scatter_elem_sz_prev = PAGE_SIZE;
1914                 } else
1915                         scatter_elem_sz_prev = num;
1916         }
1917
1918         if (sdp->device->host->unchecked_isa_dma)
1919                 gfp_mask |= GFP_DMA;
1920
1921         order = get_order(num);
1922 retry:
1923         ret_sz = 1 << (PAGE_SHIFT + order);
1924
1925         for (k = 0, rem_sz = blk_size; rem_sz > 0 && k < mx_sc_elems;
1926              k++, rem_sz -= ret_sz) {
1927
1928                 num = (rem_sz > scatter_elem_sz_prev) ?
1929                         scatter_elem_sz_prev : rem_sz;
1930
1931                 schp->pages[k] = alloc_pages(gfp_mask, order);
1932                 if (!schp->pages[k])
1933                         goto out;
1934
1935                 if (num == scatter_elem_sz_prev) {
1936                         if (unlikely(ret_sz > scatter_elem_sz_prev)) {
1937                                 scatter_elem_sz = ret_sz;
1938                                 scatter_elem_sz_prev = ret_sz;
1939                         }
1940                 }
1941
1942                 SCSI_LOG_TIMEOUT(5, sg_printk(KERN_INFO, sfp->parentdp,
1943                                  "sg_build_indirect: k=%d, num=%d, ret_sz=%d\n",
1944                                  k, num, ret_sz));
1945         }               /* end of for loop */
1946
1947         schp->page_order = order;
1948         schp->k_use_sg = k;
1949         SCSI_LOG_TIMEOUT(5, sg_printk(KERN_INFO, sfp->parentdp,
1950                          "sg_build_indirect: k_use_sg=%d, rem_sz=%d\n",
1951                          k, rem_sz));
1952
1953         schp->bufflen = blk_size;
1954         if (rem_sz > 0) /* must have failed */
1955                 return -ENOMEM;
1956         return 0;
1957 out:
1958         for (i = 0; i < k; i++)
1959                 __free_pages(schp->pages[i], order);
1960
1961         if (--order >= 0)
1962                 goto retry;
1963
1964         return -ENOMEM;
1965 }
1966
1967 static void
1968 sg_remove_scat(Sg_fd * sfp, Sg_scatter_hold * schp)
1969 {
1970         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1971                          "sg_remove_scat: k_use_sg=%d\n", schp->k_use_sg));
1972         if (schp->pages && schp->sglist_len > 0) {
1973                 if (!schp->dio_in_use) {
1974                         int k;
1975
1976                         for (k = 0; k < schp->k_use_sg && schp->pages[k]; k++) {
1977                                 SCSI_LOG_TIMEOUT(5,
1978                                         sg_printk(KERN_INFO, sfp->parentdp,
1979                                         "sg_remove_scat: k=%d, pg=0x%p\n",
1980                                         k, schp->pages[k]));
1981                                 __free_pages(schp->pages[k], schp->page_order);
1982                         }
1983
1984                         kfree(schp->pages);
1985                 }
1986         }
1987         memset(schp, 0, sizeof (*schp));
1988 }
1989
1990 static int
1991 sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer)
1992 {
1993         Sg_scatter_hold *schp = &srp->data;
1994         int k, num;
1995
1996         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, srp->parentfp->parentdp,
1997                          "sg_read_oxfer: num_read_xfer=%d\n",
1998                          num_read_xfer));
1999         if ((!outp) || (num_read_xfer <= 0))
2000                 return 0;
2001
2002         num = 1 << (PAGE_SHIFT + schp->page_order);
2003         for (k = 0; k < schp->k_use_sg && schp->pages[k]; k++) {
2004                 if (num > num_read_xfer) {
2005                         if (copy_to_user(outp, page_address(schp->pages[k]),
2006                                            num_read_xfer))
2007                                 return -EFAULT;
2008                         break;
2009                 } else {
2010                         if (copy_to_user(outp, page_address(schp->pages[k]),
2011                                            num))
2012                                 return -EFAULT;
2013                         num_read_xfer -= num;
2014                         if (num_read_xfer <= 0)
2015                                 break;
2016                         outp += num;
2017                 }
2018         }
2019
2020         return 0;
2021 }
2022
2023 static void
2024 sg_build_reserve(Sg_fd * sfp, int req_size)
2025 {
2026         Sg_scatter_hold *schp = &sfp->reserve;
2027
2028         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
2029                          "sg_build_reserve: req_size=%d\n", req_size));
2030         do {
2031                 if (req_size < PAGE_SIZE)
2032                         req_size = PAGE_SIZE;
2033                 if (0 == sg_build_indirect(schp, sfp, req_size))
2034                         return;
2035                 else
2036                         sg_remove_scat(sfp, schp);
2037                 req_size >>= 1; /* divide by 2 */
2038         } while (req_size > (PAGE_SIZE / 2));
2039 }
2040
2041 static void
2042 sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size)
2043 {
2044         Sg_scatter_hold *req_schp = &srp->data;
2045         Sg_scatter_hold *rsv_schp = &sfp->reserve;
2046         int k, num, rem;
2047
2048         srp->res_used = 1;
2049         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
2050                          "sg_link_reserve: size=%d\n", size));
2051         rem = size;
2052
2053         num = 1 << (PAGE_SHIFT + rsv_schp->page_order);
2054         for (k = 0; k < rsv_schp->k_use_sg; k++) {
2055                 if (rem <= num) {
2056                         req_schp->k_use_sg = k + 1;
2057                         req_schp->sglist_len = rsv_schp->sglist_len;
2058                         req_schp->pages = rsv_schp->pages;
2059
2060                         req_schp->bufflen = size;
2061                         req_schp->page_order = rsv_schp->page_order;
2062                         break;
2063                 } else
2064                         rem -= num;
2065         }
2066
2067         if (k >= rsv_schp->k_use_sg)
2068                 SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sfp->parentdp,
2069                                  "sg_link_reserve: BAD size\n"));
2070 }
2071
2072 static void
2073 sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp)
2074 {
2075         Sg_scatter_hold *req_schp = &srp->data;
2076
2077         SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, srp->parentfp->parentdp,
2078                                       "sg_unlink_reserve: req->k_use_sg=%d\n",
2079                                       (int) req_schp->k_use_sg));
2080         req_schp->k_use_sg = 0;
2081         req_schp->bufflen = 0;
2082         req_schp->pages = NULL;
2083         req_schp->page_order = 0;
2084         req_schp->sglist_len = 0;
2085         srp->res_used = 0;
2086         /* Called without mutex lock to avoid deadlock */
2087         sfp->res_in_use = 0;
2088 }
2089
2090 static Sg_request *
2091 sg_get_rq_mark(Sg_fd * sfp, int pack_id, bool *busy)
2092 {
2093         Sg_request *resp;
2094         unsigned long iflags;
2095
2096         *busy = false;
2097         write_lock_irqsave(&sfp->rq_list_lock, iflags);
2098         list_for_each_entry(resp, &sfp->rq_list, entry) {
2099                 /* look for requests that are not SG_IO owned */
2100                 if ((!resp->sg_io_owned) &&
2101                     ((-1 == pack_id) || (resp->header.pack_id == pack_id))) {
2102                         switch (resp->done) {
2103                         case 0: /* request active */
2104                                 *busy = true;
2105                                 break;
2106                         case 1: /* request done; response ready to return */
2107                                 resp->done = 2; /* guard against other readers */
2108                                 write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2109                                 return resp;
2110                         case 2: /* response already being returned */
2111                                 break;
2112                         }
2113                 }
2114         }
2115         write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2116         return NULL;
2117 }
2118
2119 /* always adds to end of list */
2120 static Sg_request *
2121 sg_add_request(Sg_fd * sfp)
2122 {
2123         int k;
2124         unsigned long iflags;
2125         Sg_request *rp = sfp->req_arr;
2126
2127         write_lock_irqsave(&sfp->rq_list_lock, iflags);
2128         if (!list_empty(&sfp->rq_list)) {
2129                 if (!sfp->cmd_q)
2130                         goto out_unlock;
2131
2132                 for (k = 0; k < SG_MAX_QUEUE; ++k, ++rp) {
2133                         if (!rp->parentfp)
2134                                 break;
2135                 }
2136                 if (k >= SG_MAX_QUEUE)
2137                         goto out_unlock;
2138         }
2139         memset(rp, 0, sizeof (Sg_request));
2140         rp->parentfp = sfp;
2141         rp->header.duration = jiffies_to_msecs(jiffies);
2142         list_add_tail(&rp->entry, &sfp->rq_list);
2143         write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2144         return rp;
2145 out_unlock:
2146         write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2147         return NULL;
2148 }
2149
2150 /* Return of 1 for found; 0 for not found */
2151 static int
2152 sg_remove_request(Sg_fd * sfp, Sg_request * srp)
2153 {
2154         unsigned long iflags;
2155         int res = 0;
2156
2157         if (!sfp || !srp || list_empty(&sfp->rq_list))
2158                 return res;
2159         write_lock_irqsave(&sfp->rq_list_lock, iflags);
2160         if (!list_empty(&srp->entry)) {
2161                 list_del(&srp->entry);
2162                 srp->parentfp = NULL;
2163                 res = 1;
2164         }
2165         write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2166
2167         /*
2168          * If the device is detaching, wakeup any readers in case we just
2169          * removed the last response, which would leave nothing for them to
2170          * return other than -ENODEV.
2171          */
2172         if (unlikely(atomic_read(&sfp->parentdp->detaching)))
2173                 wake_up_interruptible_all(&sfp->read_wait);
2174
2175         return res;
2176 }
2177
2178 static Sg_fd *
2179 sg_add_sfp(Sg_device * sdp)
2180 {
2181         Sg_fd *sfp;
2182         unsigned long iflags;
2183         int bufflen;
2184
2185         sfp = kzalloc(sizeof(*sfp), GFP_ATOMIC | __GFP_NOWARN);
2186         if (!sfp)
2187                 return ERR_PTR(-ENOMEM);
2188
2189         init_waitqueue_head(&sfp->read_wait);
2190         rwlock_init(&sfp->rq_list_lock);
2191         INIT_LIST_HEAD(&sfp->rq_list);
2192         kref_init(&sfp->f_ref);
2193         mutex_init(&sfp->f_mutex);
2194         sfp->timeout = SG_DEFAULT_TIMEOUT;
2195         sfp->timeout_user = SG_DEFAULT_TIMEOUT_USER;
2196         sfp->force_packid = SG_DEF_FORCE_PACK_ID;
2197         sfp->cmd_q = SG_DEF_COMMAND_Q;
2198         sfp->keep_orphan = SG_DEF_KEEP_ORPHAN;
2199         sfp->parentdp = sdp;
2200         write_lock_irqsave(&sdp->sfd_lock, iflags);
2201         if (atomic_read(&sdp->detaching)) {
2202                 write_unlock_irqrestore(&sdp->sfd_lock, iflags);
2203                 kfree(sfp);
2204                 return ERR_PTR(-ENODEV);
2205         }
2206         list_add_tail(&sfp->sfd_siblings, &sdp->sfds);
2207         write_unlock_irqrestore(&sdp->sfd_lock, iflags);
2208         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
2209                                       "sg_add_sfp: sfp=0x%p\n", sfp));
2210         if (unlikely(sg_big_buff != def_reserved_size))
2211                 sg_big_buff = def_reserved_size;
2212
2213         bufflen = min_t(int, sg_big_buff,
2214                         max_sectors_bytes(sdp->device->request_queue));
2215         sg_build_reserve(sfp, bufflen);
2216         SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
2217                                       "sg_add_sfp: bufflen=%d, k_use_sg=%d\n",
2218                                       sfp->reserve.bufflen,
2219                                       sfp->reserve.k_use_sg));
2220
2221         kref_get(&sdp->d_ref);
2222         __module_get(THIS_MODULE);
2223         return sfp;
2224 }
2225
2226 static void
2227 sg_remove_sfp_usercontext(struct work_struct *work)
2228 {
2229         struct sg_fd *sfp = container_of(work, struct sg_fd, ew.work);
2230         struct sg_device *sdp = sfp->parentdp;
2231         Sg_request *srp;
2232         unsigned long iflags;
2233
2234         /* Cleanup any responses which were never read(). */
2235         write_lock_irqsave(&sfp->rq_list_lock, iflags);
2236         while (!list_empty(&sfp->rq_list)) {
2237                 srp = list_first_entry(&sfp->rq_list, Sg_request, entry);
2238                 sg_finish_rem_req(srp);
2239                 list_del(&srp->entry);
2240                 srp->parentfp = NULL;
2241         }
2242         write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2243
2244         if (sfp->reserve.bufflen > 0) {
2245                 SCSI_LOG_TIMEOUT(6, sg_printk(KERN_INFO, sdp,
2246                                 "sg_remove_sfp:    bufflen=%d, k_use_sg=%d\n",
2247                                 (int) sfp->reserve.bufflen,
2248                                 (int) sfp->reserve.k_use_sg));
2249                 sg_remove_scat(sfp, &sfp->reserve);
2250         }
2251
2252         SCSI_LOG_TIMEOUT(6, sg_printk(KERN_INFO, sdp,
2253                         "sg_remove_sfp: sfp=0x%p\n", sfp));
2254         kfree(sfp);
2255
2256         scsi_device_put(sdp->device);
2257         kref_put(&sdp->d_ref, sg_device_destroy);
2258         module_put(THIS_MODULE);
2259 }
2260
2261 static void
2262 sg_remove_sfp(struct kref *kref)
2263 {
2264         struct sg_fd *sfp = container_of(kref, struct sg_fd, f_ref);
2265         struct sg_device *sdp = sfp->parentdp;
2266         unsigned long iflags;
2267
2268         write_lock_irqsave(&sdp->sfd_lock, iflags);
2269         list_del(&sfp->sfd_siblings);
2270         write_unlock_irqrestore(&sdp->sfd_lock, iflags);
2271
2272         INIT_WORK(&sfp->ew.work, sg_remove_sfp_usercontext);
2273         schedule_work(&sfp->ew.work);
2274 }
2275
2276 #ifdef CONFIG_SCSI_PROC_FS
2277 static int
2278 sg_idr_max_id(int id, void *p, void *data)
2279 {
2280         int *k = data;
2281
2282         if (*k < id)
2283                 *k = id;
2284
2285         return 0;
2286 }
2287
2288 static int
2289 sg_last_dev(void)
2290 {
2291         int k = -1;
2292         unsigned long iflags;
2293
2294         read_lock_irqsave(&sg_index_lock, iflags);
2295         idr_for_each(&sg_index_idr, sg_idr_max_id, &k);
2296         read_unlock_irqrestore(&sg_index_lock, iflags);
2297         return k + 1;           /* origin 1 */
2298 }
2299 #endif
2300
2301 /* must be called with sg_index_lock held */
2302 static Sg_device *sg_lookup_dev(int dev)
2303 {
2304         return idr_find(&sg_index_idr, dev);
2305 }
2306
2307 static Sg_device *
2308 sg_get_dev(int dev)
2309 {
2310         struct sg_device *sdp;
2311         unsigned long flags;
2312
2313         read_lock_irqsave(&sg_index_lock, flags);
2314         sdp = sg_lookup_dev(dev);
2315         if (!sdp)
2316                 sdp = ERR_PTR(-ENXIO);
2317         else if (atomic_read(&sdp->detaching)) {
2318                 /* If sdp->detaching, then the refcount may already be 0, in
2319                  * which case it would be a bug to do kref_get().
2320                  */
2321                 sdp = ERR_PTR(-ENODEV);
2322         } else
2323                 kref_get(&sdp->d_ref);
2324         read_unlock_irqrestore(&sg_index_lock, flags);
2325
2326         return sdp;
2327 }
2328
2329 #ifdef CONFIG_SCSI_PROC_FS
2330 static int sg_proc_seq_show_int(struct seq_file *s, void *v);
2331
2332 static int sg_proc_single_open_adio(struct inode *inode, struct file *file);
2333 static ssize_t sg_proc_write_adio(struct file *filp, const char __user *buffer,
2334                                   size_t count, loff_t *off);
2335 static const struct proc_ops adio_proc_ops = {
2336         .proc_open      = sg_proc_single_open_adio,
2337         .proc_read      = seq_read,
2338         .proc_lseek     = seq_lseek,
2339         .proc_write     = sg_proc_write_adio,
2340         .proc_release   = single_release,
2341 };
2342
2343 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file);
2344 static ssize_t sg_proc_write_dressz(struct file *filp,
2345                 const char __user *buffer, size_t count, loff_t *off);
2346 static const struct proc_ops dressz_proc_ops = {
2347         .proc_open      = sg_proc_single_open_dressz,
2348         .proc_read      = seq_read,
2349         .proc_lseek     = seq_lseek,
2350         .proc_write     = sg_proc_write_dressz,
2351         .proc_release   = single_release,
2352 };
2353
2354 static int sg_proc_seq_show_version(struct seq_file *s, void *v);
2355 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v);
2356 static int sg_proc_seq_show_dev(struct seq_file *s, void *v);
2357 static void * dev_seq_start(struct seq_file *s, loff_t *pos);
2358 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos);
2359 static void dev_seq_stop(struct seq_file *s, void *v);
2360 static const struct seq_operations dev_seq_ops = {
2361         .start = dev_seq_start,
2362         .next  = dev_seq_next,
2363         .stop  = dev_seq_stop,
2364         .show  = sg_proc_seq_show_dev,
2365 };
2366
2367 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v);
2368 static const struct seq_operations devstrs_seq_ops = {
2369         .start = dev_seq_start,
2370         .next  = dev_seq_next,
2371         .stop  = dev_seq_stop,
2372         .show  = sg_proc_seq_show_devstrs,
2373 };
2374
2375 static int sg_proc_seq_show_debug(struct seq_file *s, void *v);
2376 static const struct seq_operations debug_seq_ops = {
2377         .start = dev_seq_start,
2378         .next  = dev_seq_next,
2379         .stop  = dev_seq_stop,
2380         .show  = sg_proc_seq_show_debug,
2381 };
2382
2383 static int
2384 sg_proc_init(void)
2385 {
2386         struct proc_dir_entry *p;
2387
2388         p = proc_mkdir("scsi/sg", NULL);
2389         if (!p)
2390                 return 1;
2391
2392         proc_create("allow_dio", S_IRUGO | S_IWUSR, p, &adio_proc_ops);
2393         proc_create_seq("debug", S_IRUGO, p, &debug_seq_ops);
2394         proc_create("def_reserved_size", S_IRUGO | S_IWUSR, p, &dressz_proc_ops);
2395         proc_create_single("device_hdr", S_IRUGO, p, sg_proc_seq_show_devhdr);
2396         proc_create_seq("devices", S_IRUGO, p, &dev_seq_ops);
2397         proc_create_seq("device_strs", S_IRUGO, p, &devstrs_seq_ops);
2398         proc_create_single("version", S_IRUGO, p, sg_proc_seq_show_version);
2399         return 0;
2400 }
2401
2402
2403 static int sg_proc_seq_show_int(struct seq_file *s, void *v)
2404 {
2405         seq_printf(s, "%d\n", *((int *)s->private));
2406         return 0;
2407 }
2408
2409 static int sg_proc_single_open_adio(struct inode *inode, struct file *file)
2410 {
2411         return single_open(file, sg_proc_seq_show_int, &sg_allow_dio);
2412 }
2413
2414 static ssize_t
2415 sg_proc_write_adio(struct file *filp, const char __user *buffer,
2416                    size_t count, loff_t *off)
2417 {
2418         int err;
2419         unsigned long num;
2420
2421         if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2422                 return -EACCES;
2423         err = kstrtoul_from_user(buffer, count, 0, &num);
2424         if (err)
2425                 return err;
2426         sg_allow_dio = num ? 1 : 0;
2427         return count;
2428 }
2429
2430 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file)
2431 {
2432         return single_open(file, sg_proc_seq_show_int, &sg_big_buff);
2433 }
2434
2435 static ssize_t
2436 sg_proc_write_dressz(struct file *filp, const char __user *buffer,
2437                      size_t count, loff_t *off)
2438 {
2439         int err;
2440         unsigned long k = ULONG_MAX;
2441
2442         if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2443                 return -EACCES;
2444
2445         err = kstrtoul_from_user(buffer, count, 0, &k);
2446         if (err)
2447                 return err;
2448         if (k <= 1048576) {     /* limit "big buff" to 1 MB */
2449                 sg_big_buff = k;
2450                 return count;
2451         }
2452         return -ERANGE;
2453 }
2454
2455 static int sg_proc_seq_show_version(struct seq_file *s, void *v)
2456 {
2457         seq_printf(s, "%d\t%s [%s]\n", sg_version_num, SG_VERSION_STR,
2458                    sg_version_date);
2459         return 0;
2460 }
2461
2462 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v)
2463 {
2464         seq_puts(s, "host\tchan\tid\tlun\ttype\topens\tqdepth\tbusy\tonline\n");
2465         return 0;
2466 }
2467
2468 struct sg_proc_deviter {
2469         loff_t  index;
2470         size_t  max;
2471 };
2472
2473 static void * dev_seq_start(struct seq_file *s, loff_t *pos)
2474 {
2475         struct sg_proc_deviter * it = kmalloc(sizeof(*it), GFP_KERNEL);
2476
2477         s->private = it;
2478         if (! it)
2479                 return NULL;
2480
2481         it->index = *pos;
2482         it->max = sg_last_dev();
2483         if (it->index >= it->max)
2484                 return NULL;
2485         return it;
2486 }
2487
2488 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos)
2489 {
2490         struct sg_proc_deviter * it = s->private;
2491
2492         *pos = ++it->index;
2493         return (it->index < it->max) ? it : NULL;
2494 }
2495
2496 static void dev_seq_stop(struct seq_file *s, void *v)
2497 {
2498         kfree(s->private);
2499 }
2500
2501 static int sg_proc_seq_show_dev(struct seq_file *s, void *v)
2502 {
2503         struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2504         Sg_device *sdp;
2505         struct scsi_device *scsidp;
2506         unsigned long iflags;
2507
2508         read_lock_irqsave(&sg_index_lock, iflags);
2509         sdp = it ? sg_lookup_dev(it->index) : NULL;
2510         if ((NULL == sdp) || (NULL == sdp->device) ||
2511             (atomic_read(&sdp->detaching)))
2512                 seq_puts(s, "-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\n");
2513         else {
2514                 scsidp = sdp->device;
2515                 seq_printf(s, "%d\t%d\t%d\t%llu\t%d\t%d\t%d\t%d\t%d\n",
2516                               scsidp->host->host_no, scsidp->channel,
2517                               scsidp->id, scsidp->lun, (int) scsidp->type,
2518                               1,
2519                               (int) scsidp->queue_depth,
2520                               (int) atomic_read(&scsidp->device_busy),
2521                               (int) scsi_device_online(scsidp));
2522         }
2523         read_unlock_irqrestore(&sg_index_lock, iflags);
2524         return 0;
2525 }
2526
2527 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v)
2528 {
2529         struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2530         Sg_device *sdp;
2531         struct scsi_device *scsidp;
2532         unsigned long iflags;
2533
2534         read_lock_irqsave(&sg_index_lock, iflags);
2535         sdp = it ? sg_lookup_dev(it->index) : NULL;
2536         scsidp = sdp ? sdp->device : NULL;
2537         if (sdp && scsidp && (!atomic_read(&sdp->detaching)))
2538                 seq_printf(s, "%8.8s\t%16.16s\t%4.4s\n",
2539                            scsidp->vendor, scsidp->model, scsidp->rev);
2540         else
2541                 seq_puts(s, "<no active device>\n");
2542         read_unlock_irqrestore(&sg_index_lock, iflags);
2543         return 0;
2544 }
2545
2546 /* must be called while holding sg_index_lock */
2547 static void sg_proc_debug_helper(struct seq_file *s, Sg_device * sdp)
2548 {
2549         int k, new_interface, blen, usg;
2550         Sg_request *srp;
2551         Sg_fd *fp;
2552         const sg_io_hdr_t *hp;
2553         const char * cp;
2554         unsigned int ms;
2555
2556         k = 0;
2557         list_for_each_entry(fp, &sdp->sfds, sfd_siblings) {
2558                 k++;
2559                 read_lock(&fp->rq_list_lock); /* irqs already disabled */
2560                 seq_printf(s, "   FD(%d): timeout=%dms bufflen=%d "
2561                            "(res)sgat=%d low_dma=%d\n", k,
2562                            jiffies_to_msecs(fp->timeout),
2563                            fp->reserve.bufflen,
2564                            (int) fp->reserve.k_use_sg,
2565                            (int) sdp->device->host->unchecked_isa_dma);
2566                 seq_printf(s, "   cmd_q=%d f_packid=%d k_orphan=%d closed=0\n",
2567                            (int) fp->cmd_q, (int) fp->force_packid,
2568                            (int) fp->keep_orphan);
2569                 list_for_each_entry(srp, &fp->rq_list, entry) {
2570                         hp = &srp->header;
2571                         new_interface = (hp->interface_id == '\0') ? 0 : 1;
2572                         if (srp->res_used) {
2573                                 if (new_interface &&
2574                                     (SG_FLAG_MMAP_IO & hp->flags))
2575                                         cp = "     mmap>> ";
2576                                 else
2577                                         cp = "     rb>> ";
2578                         } else {
2579                                 if (SG_INFO_DIRECT_IO_MASK & hp->info)
2580                                         cp = "     dio>> ";
2581                                 else
2582                                         cp = "     ";
2583                         }
2584                         seq_puts(s, cp);
2585                         blen = srp->data.bufflen;
2586                         usg = srp->data.k_use_sg;
2587                         seq_puts(s, srp->done ?
2588                                  ((1 == srp->done) ?  "rcv:" : "fin:")
2589                                   : "act:");
2590                         seq_printf(s, " id=%d blen=%d",
2591                                    srp->header.pack_id, blen);
2592                         if (srp->done)
2593                                 seq_printf(s, " dur=%d", hp->duration);
2594                         else {
2595                                 ms = jiffies_to_msecs(jiffies);
2596                                 seq_printf(s, " t_o/elap=%d/%d",
2597                                         (new_interface ? hp->timeout :
2598                                                   jiffies_to_msecs(fp->timeout)),
2599                                         (ms > hp->duration ? ms - hp->duration : 0));
2600                         }
2601                         seq_printf(s, "ms sgat=%d op=0x%02x\n", usg,
2602                                    (int) srp->data.cmd_opcode);
2603                 }
2604                 if (list_empty(&fp->rq_list))
2605                         seq_puts(s, "     No requests active\n");
2606                 read_unlock(&fp->rq_list_lock);
2607         }
2608 }
2609
2610 static int sg_proc_seq_show_debug(struct seq_file *s, void *v)
2611 {
2612         struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2613         Sg_device *sdp;
2614         unsigned long iflags;
2615
2616         if (it && (0 == it->index))
2617                 seq_printf(s, "max_active_device=%d  def_reserved_size=%d\n",
2618                            (int)it->max, sg_big_buff);
2619
2620         read_lock_irqsave(&sg_index_lock, iflags);
2621         sdp = it ? sg_lookup_dev(it->index) : NULL;
2622         if (NULL == sdp)
2623                 goto skip;
2624         read_lock(&sdp->sfd_lock);
2625         if (!list_empty(&sdp->sfds)) {
2626                 seq_printf(s, " >>> device=%s ", sdp->disk->disk_name);
2627                 if (atomic_read(&sdp->detaching))
2628                         seq_puts(s, "detaching pending close ");
2629                 else if (sdp->device) {
2630                         struct scsi_device *scsidp = sdp->device;
2631
2632                         seq_printf(s, "%d:%d:%d:%llu   em=%d",
2633                                    scsidp->host->host_no,
2634                                    scsidp->channel, scsidp->id,
2635                                    scsidp->lun,
2636                                    scsidp->host->hostt->emulated);
2637                 }
2638                 seq_printf(s, " sg_tablesize=%d excl=%d open_cnt=%d\n",
2639                            sdp->sg_tablesize, sdp->exclude, sdp->open_cnt);
2640                 sg_proc_debug_helper(s, sdp);
2641         }
2642         read_unlock(&sdp->sfd_lock);
2643 skip:
2644         read_unlock_irqrestore(&sg_index_lock, iflags);
2645         return 0;
2646 }
2647
2648 #endif                          /* CONFIG_SCSI_PROC_FS */
2649
2650 module_init(init_sg);
2651 module_exit(exit_sg);