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