drivers/scsi/scsi_error.c

   1 /*
   2  *  scsi_error.c Copyright (C) 1997 Eric Youngdale
   3  *
   4  *  SCSI error/timeout handling
   5  *      Initial versions: Eric Youngdale.  Based upon conversations with
   6  *                        Leonard Zubkoff and David Miller at Linux Expo,
   7  *                        ideas originating from all over the place.
   8  *
   9  *      Restructured scsi_unjam_host and associated functions.
  10  *      September 04, 2002 Mike Anderson (andmike@us.ibm.com)
  11  *
  12  *      Forward port of Russell King's (rmk@arm.linux.org.uk) changes and
  13  *      minor cleanups.
  14  *      September 30, 2002 Mike Anderson (andmike@us.ibm.com)
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/sched.h>
  19 #include <linux/gfp.h>
  20 #include <linux/timer.h>
  21 #include <linux/string.h>
  22 #include <linux/kernel.h>
  23 #include <linux/freezer.h>
  24 #include <linux/kthread.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/blkdev.h>
  27 #include <linux/delay.h>
  28 #include <linux/jiffies.h>
  29
  30 #include <scsi/scsi.h>
  31 #include <scsi/scsi_cmnd.h>
  32 #include <scsi/scsi_dbg.h>
  33 #include <scsi/scsi_device.h>
  34 #include <scsi/scsi_driver.h>
  35 #include <scsi/scsi_eh.h>
  36 #include <scsi/scsi_common.h>
  37 #include <scsi/scsi_transport.h>
  38 #include <scsi/scsi_host.h>
  39 #include <scsi/scsi_ioctl.h>
  40 #include <scsi/scsi_dh.h>
  41 #include <scsi/sg.h>
  42
  43 #include "scsi_priv.h"
  44 #include "scsi_logging.h"
  45 #include "scsi_transport_api.h"
  46
  47 #include <trace/events/scsi.h>
  48
  49 static void scsi_eh_done(struct scsi_cmnd *scmd);
  50
  51 /*
  52  * These should *probably* be handled by the host itself.
  53  * Since it is allowed to sleep, it probably should.
  54  */
  55 #define BUS_RESET_SETTLE_TIME   (10)
  56 #define HOST_RESET_SETTLE_TIME  (10)
  57
  58 static int scsi_eh_try_stu(struct scsi_cmnd *scmd);
  59 static int scsi_try_to_abort_cmd(struct scsi_host_template *,
  60                                  struct scsi_cmnd *);
  61
  62 /* called with shost->host_lock held */
  63 void scsi_eh_wakeup(struct Scsi_Host *shost)
  64 {
  65         if (atomic_read(&shost->host_busy) == shost->host_failed) {
  66                 trace_scsi_eh_wakeup(shost);
  67                 wake_up_process(shost->ehandler);
  68                 SCSI_LOG_ERROR_RECOVERY(5, shost_printk(KERN_INFO, shost,
  69                         "Waking error handler thread\n"));
  70         }
  71 }
  72
  73 /**
  74  * scsi_schedule_eh - schedule EH for SCSI host
  75  * @shost:      SCSI host to invoke error handling on.
  76  *
  77  * Schedule SCSI EH without scmd.
  78  */
  79 void scsi_schedule_eh(struct Scsi_Host *shost)
  80 {
  81         unsigned long flags;
  82
  83         spin_lock_irqsave(shost->host_lock, flags);
  84
  85         if (scsi_host_set_state(shost, SHOST_RECOVERY) == 0 ||
  86             scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY) == 0) {
  87                 shost->host_eh_scheduled++;
  88                 scsi_eh_wakeup(shost);
  89         }
  90
  91         spin_unlock_irqrestore(shost->host_lock, flags);
  92 }
  93 EXPORT_SYMBOL_GPL(scsi_schedule_eh);
  94
  95 static int scsi_host_eh_past_deadline(struct Scsi_Host *shost)
  96 {
  97         if (!shost->last_reset || shost->eh_deadline == -1)
  98                 return 0;
  99
 100         /*
 101          * 32bit accesses are guaranteed to be atomic
 102          * (on all supported architectures), so instead
 103          * of using a spinlock we can as well double check
 104          * if eh_deadline has been set to 'off' during the
 105          * time_before call.
 106          */
 107         if (time_before(jiffies, shost->last_reset + shost->eh_deadline) &&
 108             shost->eh_deadline > -1)
 109                 return 0;
 110
 111         return 1;
 112 }
 113
 114 /**
 115  * scmd_eh_abort_handler - Handle command aborts
 116  * @work:       command to be aborted.
 117  */
 118 void
 119 scmd_eh_abort_handler(struct work_struct *work)
 120 {
 121         struct scsi_cmnd *scmd =
 122                 container_of(work, struct scsi_cmnd, abort_work.work);
 123         struct scsi_device *sdev = scmd->device;
 124         int rtn;
 125
 126         if (scsi_host_eh_past_deadline(sdev->host)) {
 127                 SCSI_LOG_ERROR_RECOVERY(3,
 128                         scmd_printk(KERN_INFO, scmd,
 129                                     "eh timeout, not aborting\n"));
 130         } else {
 131                 SCSI_LOG_ERROR_RECOVERY(3,
 132                         scmd_printk(KERN_INFO, scmd,
 133                                     "aborting command\n"));
 134                 rtn = scsi_try_to_abort_cmd(sdev->host->hostt, scmd);
 135                 if (rtn == SUCCESS) {
 136                         set_host_byte(scmd, DID_TIME_OUT);
 137                         if (scsi_host_eh_past_deadline(sdev->host)) {
 138                                 SCSI_LOG_ERROR_RECOVERY(3,
 139                                         scmd_printk(KERN_INFO, scmd,
 140                                                     "eh timeout, not retrying "
 141                                                     "aborted command\n"));
 142                         } else if (!scsi_noretry_cmd(scmd) &&
 143                             (++scmd->retries <= scmd->allowed)) {
 144                                 SCSI_LOG_ERROR_RECOVERY(3,
 145                                         scmd_printk(KERN_WARNING, scmd,
 146                                                     "retry aborted command\n"));
 147                                 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
 148                                 return;
 149                         } else {
 150                                 SCSI_LOG_ERROR_RECOVERY(3,
 151                                         scmd_printk(KERN_WARNING, scmd,
 152                                                     "finish aborted command\n"));
 153                                 scsi_finish_command(scmd);
 154                                 return;
 155                         }
 156                 } else {
 157                         SCSI_LOG_ERROR_RECOVERY(3,
 158                                 scmd_printk(KERN_INFO, scmd,
 159                                             "cmd abort %s\n",
 160                                             (rtn == FAST_IO_FAIL) ?
 161                                             "not send" : "failed"));
 162                 }
 163         }
 164
 165         if (!scsi_eh_scmd_add(scmd, 0)) {
 166                 SCSI_LOG_ERROR_RECOVERY(3,
 167                         scmd_printk(KERN_WARNING, scmd,
 168                                     "terminate aborted command\n"));
 169                 set_host_byte(scmd, DID_TIME_OUT);
 170                 scsi_finish_command(scmd);
 171         }
 172 }
 173
 174 /**
 175  * scsi_abort_command - schedule a command abort
 176  * @scmd:       scmd to abort.
 177  *
 178  * We only need to abort commands after a command timeout
 179  */
 180 static int
 181 scsi_abort_command(struct scsi_cmnd *scmd)
 182 {
 183         struct scsi_device *sdev = scmd->device;
 184         struct Scsi_Host *shost = sdev->host;
 185         unsigned long flags;
 186
 187         if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) {
 188                 /*
 189                  * Retry after abort failed, escalate to next level.
 190                  */
 191                 scmd->eh_eflags &= ~SCSI_EH_ABORT_SCHEDULED;
 192                 SCSI_LOG_ERROR_RECOVERY(3,
 193                         scmd_printk(KERN_INFO, scmd,
 194                                     "previous abort failed\n"));
 195                 BUG_ON(delayed_work_pending(&scmd->abort_work));
 196                 return FAILED;
 197         }
 198
 199         /*
 200          * Do not try a command abort if
 201          * SCSI EH has already started.
 202          */
 203         spin_lock_irqsave(shost->host_lock, flags);
 204         if (scsi_host_in_recovery(shost)) {
 205                 spin_unlock_irqrestore(shost->host_lock, flags);
 206                 SCSI_LOG_ERROR_RECOVERY(3,
 207                         scmd_printk(KERN_INFO, scmd,
 208                                     "not aborting, host in recovery\n"));
 209                 return FAILED;
 210         }
 211
 212         if (shost->eh_deadline != -1 && !shost->last_reset)
 213                 shost->last_reset = jiffies;
 214         spin_unlock_irqrestore(shost->host_lock, flags);
 215
 216         scmd->eh_eflags |= SCSI_EH_ABORT_SCHEDULED;
 217         SCSI_LOG_ERROR_RECOVERY(3,
 218                 scmd_printk(KERN_INFO, scmd, "abort scheduled\n"));
 219         queue_delayed_work(shost->tmf_work_q, &scmd->abort_work, HZ / 100);
 220         return SUCCESS;
 221 }
 222
 223 /**
 224  * scsi_eh_scmd_add - add scsi cmd to error handling.
 225  * @scmd:       scmd to run eh on.
 226  * @eh_flag:    optional SCSI_EH flag.
 227  *
 228  * Return value:
 229  *      0 on failure.
 230  */
 231 int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
 232 {
 233         struct Scsi_Host *shost = scmd->device->host;
 234         unsigned long flags;
 235         int ret = 0;
 236
 237         if (!shost->ehandler)
 238                 return 0;
 239
 240         spin_lock_irqsave(shost->host_lock, flags);
 241         if (scsi_host_set_state(shost, SHOST_RECOVERY))
 242                 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY))
 243                         goto out_unlock;
 244
 245         if (shost->eh_deadline != -1 && !shost->last_reset)
 246                 shost->last_reset = jiffies;
 247
 248         ret = 1;
 249         if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED)
 250                 eh_flag &= ~SCSI_EH_CANCEL_CMD;
 251         scmd->eh_eflags |= eh_flag;
 252         list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
 253         shost->host_failed++;
 254         scsi_eh_wakeup(shost);
 255  out_unlock:
 256         spin_unlock_irqrestore(shost->host_lock, flags);
 257         return ret;
 258 }
 259
 260 /**
 261  * scsi_times_out - Timeout function for normal scsi commands.
 262  * @req:        request that is timing out.
 263  *
 264  * Notes:
 265  *     We do not need to lock this.  There is the potential for a race
 266  *     only in that the normal completion handling might run, but if the
 267  *     normal completion function determines that the timer has already
 268  *     fired, then it mustn't do anything.
 269  */
 270 enum blk_eh_timer_return scsi_times_out(struct request *req)
 271 {
 272         struct scsi_cmnd *scmd = req->special;
 273         enum blk_eh_timer_return rtn = BLK_EH_NOT_HANDLED;
 274         struct Scsi_Host *host = scmd->device->host;
 275
 276         trace_scsi_dispatch_cmd_timeout(scmd);
 277         scsi_log_completion(scmd, TIMEOUT_ERROR);
 278
 279         if (host->eh_deadline != -1 && !host->last_reset)
 280                 host->last_reset = jiffies;
 281
 282         if (host->transportt->eh_timed_out)
 283                 rtn = host->transportt->eh_timed_out(scmd);
 284         else if (host->hostt->eh_timed_out)
 285                 rtn = host->hostt->eh_timed_out(scmd);
 286
 287         if (rtn == BLK_EH_NOT_HANDLED) {
 288                 if (!host->hostt->no_async_abort &&
 289                     scsi_abort_command(scmd) == SUCCESS)
 290                         return BLK_EH_NOT_HANDLED;
 291
 292                 set_host_byte(scmd, DID_TIME_OUT);
 293                 if (!scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD))
 294                         rtn = BLK_EH_HANDLED;
 295         }
 296
 297         return rtn;
 298 }
 299
 300 /**
 301  * scsi_block_when_processing_errors - Prevent cmds from being queued.
 302  * @sdev:       Device on which we are performing recovery.
 303  *
 304  * Description:
 305  *     We block until the host is out of error recovery, and then check to
 306  *     see whether the host or the device is offline.
 307  *
 308  * Return value:
 309  *     0 when dev was taken offline by error recovery. 1 OK to proceed.
 310  */
 311 int scsi_block_when_processing_errors(struct scsi_device *sdev)
 312 {
 313         int online;
 314
 315         wait_event(sdev->host->host_wait, !scsi_host_in_recovery(sdev->host));
 316
 317         online = scsi_device_online(sdev);
 318
 319         SCSI_LOG_ERROR_RECOVERY(5, sdev_printk(KERN_INFO, sdev,
 320                 "%s: rtn: %d\n", __func__, online));
 321
 322         return online;
 323 }
 324 EXPORT_SYMBOL(scsi_block_when_processing_errors);
 325
 326 #ifdef CONFIG_SCSI_LOGGING
 327 /**
 328  * scsi_eh_prt_fail_stats - Log info on failures.
 329  * @shost:      scsi host being recovered.
 330  * @work_q:     Queue of scsi cmds to process.
 331  */
 332 static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
 333                                           struct list_head *work_q)
 334 {
 335         struct scsi_cmnd *scmd;
 336         struct scsi_device *sdev;
 337         int total_failures = 0;
 338         int cmd_failed = 0;
 339         int cmd_cancel = 0;
 340         int devices_failed = 0;
 341
 342         shost_for_each_device(sdev, shost) {
 343                 list_for_each_entry(scmd, work_q, eh_entry) {
 344                         if (scmd->device == sdev) {
 345                                 ++total_failures;
 346                                 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD)
 347                                         ++cmd_cancel;
 348                                 else
 349                                         ++cmd_failed;
 350                         }
 351                 }
 352
 353                 if (cmd_cancel || cmd_failed) {
 354                         SCSI_LOG_ERROR_RECOVERY(3,
 355                                 shost_printk(KERN_INFO, shost,
 356                                             "%s: cmds failed: %d, cancel: %d\n",
 357                                             __func__, cmd_failed,
 358                                             cmd_cancel));
 359                         cmd_cancel = 0;
 360                         cmd_failed = 0;
 361                         ++devices_failed;
 362                 }
 363         }
 364
 365         SCSI_LOG_ERROR_RECOVERY(2, shost_printk(KERN_INFO, shost,
 366                                    "Total of %d commands on %d"
 367                                    " devices require eh work\n",
 368                                    total_failures, devices_failed));
 369 }
 370 #endif
 371
 372  /**
 373  * scsi_report_lun_change - Set flag on all *other* devices on the same target
 374  *                          to indicate that a UNIT ATTENTION is expected.
 375  * @sdev:       Device reporting the UNIT ATTENTION
 376  */
 377 static void scsi_report_lun_change(struct scsi_device *sdev)
 378 {
 379         sdev->sdev_target->expecting_lun_change = 1;
 380 }
 381
 382 /**
 383  * scsi_report_sense - Examine scsi sense information and log messages for
 384  *                     certain conditions, also issue uevents for some of them.
 385  * @sdev:       Device reporting the sense code
 386  * @sshdr:      sshdr to be examined
 387  */
 388 static void scsi_report_sense(struct scsi_device *sdev,
 389                               struct scsi_sense_hdr *sshdr)
 390 {
 391         enum scsi_device_event evt_type = SDEV_EVT_MAXBITS;     /* i.e. none */
 392
 393         if (sshdr->sense_key == UNIT_ATTENTION) {
 394                 if (sshdr->asc == 0x3f && sshdr->ascq == 0x03) {
 395                         evt_type = SDEV_EVT_INQUIRY_CHANGE_REPORTED;
 396                         sdev_printk(KERN_WARNING, sdev,
 397                                     "Inquiry data has changed");
 398                 } else if (sshdr->asc == 0x3f && sshdr->ascq == 0x0e) {
 399                         evt_type = SDEV_EVT_LUN_CHANGE_REPORTED;
 400                         scsi_report_lun_change(sdev);
 401                         sdev_printk(KERN_WARNING, sdev,
 402                                     "Warning! Received an indication that the "
 403                                     "LUN assignments on this target have "
 404                                     "changed. The Linux SCSI layer does not "
 405                                     "automatically remap LUN assignments.\n");
 406                 } else if (sshdr->asc == 0x3f)
 407                         sdev_printk(KERN_WARNING, sdev,
 408                                     "Warning! Received an indication that the "
 409                                     "operating parameters on this target have "
 410                                     "changed. The Linux SCSI layer does not "
 411                                     "automatically adjust these parameters.\n");
 412
 413                 if (sshdr->asc == 0x38 && sshdr->ascq == 0x07) {
 414                         evt_type = SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED;
 415                         sdev_printk(KERN_WARNING, sdev,
 416                                     "Warning! Received an indication that the "
 417                                     "LUN reached a thin provisioning soft "
 418                                     "threshold.\n");
 419                 }
 420
 421                 if (sshdr->asc == 0x2a && sshdr->ascq == 0x01) {
 422                         evt_type = SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED;
 423                         sdev_printk(KERN_WARNING, sdev,
 424                                     "Mode parameters changed");
 425                 } else if (sshdr->asc == 0x2a && sshdr->ascq == 0x06) {
 426                         evt_type = SDEV_EVT_ALUA_STATE_CHANGE_REPORTED;
 427                         sdev_printk(KERN_WARNING, sdev,
 428                                     "Asymmetric access state changed");
 429                 } else if (sshdr->asc == 0x2a && sshdr->ascq == 0x09) {
 430                         evt_type = SDEV_EVT_CAPACITY_CHANGE_REPORTED;
 431                         sdev_printk(KERN_WARNING, sdev,
 432                                     "Capacity data has changed");
 433                 } else if (sshdr->asc == 0x2a)
 434                         sdev_printk(KERN_WARNING, sdev,
 435                                     "Parameters changed");
 436         }
 437
 438         if (evt_type != SDEV_EVT_MAXBITS) {
 439                 set_bit(evt_type, sdev->pending_events);
 440                 schedule_work(&sdev->event_work);
 441         }
 442 }
 443
 444 /**
 445  * scsi_check_sense - Examine scsi cmd sense
 446  * @scmd:       Cmd to have sense checked.
 447  *
 448  * Return value:
 449  *      SUCCESS or FAILED or NEEDS_RETRY or ADD_TO_MLQUEUE
 450  *
 451  * Notes:
 452  *      When a deferred error is detected the current command has
 453  *      not been executed and needs retrying.
 454  */
 455 int scsi_check_sense(struct scsi_cmnd *scmd)
 456 {
 457         struct scsi_device *sdev = scmd->device;
 458         struct scsi_sense_hdr sshdr;
 459
 460         if (! scsi_command_normalize_sense(scmd, &sshdr))
 461                 return FAILED;  /* no valid sense data */
 462
 463         scsi_report_sense(sdev, &sshdr);
 464
 465         if (scsi_sense_is_deferred(&sshdr))
 466                 return NEEDS_RETRY;
 467
 468         if (sdev->handler && sdev->handler->check_sense) {
 469                 int rc;
 470
 471                 rc = sdev->handler->check_sense(sdev, &sshdr);
 472                 if (rc != SCSI_RETURN_NOT_HANDLED)
 473                         return rc;
 474                 /* handler does not care. Drop down to default handling */
 475         }
 476
 477         if (scmd->cmnd[0] == TEST_UNIT_READY && scmd->scsi_done != scsi_eh_done)
 478                 /*
 479                  * nasty: for mid-layer issued TURs, we need to return the
 480                  * actual sense data without any recovery attempt.  For eh
 481                  * issued ones, we need to try to recover and interpret
 482                  */
 483                 return SUCCESS;
 484
 485         /*
 486          * Previous logic looked for FILEMARK, EOM or ILI which are
 487          * mainly associated with tapes and returned SUCCESS.
 488          */
 489         if (sshdr.response_code == 0x70) {
 490                 /* fixed format */
 491                 if (scmd->sense_buffer[2] & 0xe0)
 492                         return SUCCESS;
 493         } else {
 494                 /*
 495                  * descriptor format: look for "stream commands sense data
 496                  * descriptor" (see SSC-3). Assume single sense data
 497                  * descriptor. Ignore ILI from SBC-2 READ LONG and WRITE LONG.
 498                  */
 499                 if ((sshdr.additional_length > 3) &&
 500                     (scmd->sense_buffer[8] == 0x4) &&
 501                     (scmd->sense_buffer[11] & 0xe0))
 502                         return SUCCESS;
 503         }
 504
 505         switch (sshdr.sense_key) {
 506         case NO_SENSE:
 507                 return SUCCESS;
 508         case RECOVERED_ERROR:
 509                 return /* soft_error */ SUCCESS;
 510
 511         case ABORTED_COMMAND:
 512                 if (sshdr.asc == 0x10) /* DIF */
 513                         return SUCCESS;
 514
 515                 return NEEDS_RETRY;
 516         case NOT_READY:
 517         case UNIT_ATTENTION:
 518                 /*
 519                  * if we are expecting a cc/ua because of a bus reset that we
 520                  * performed, treat this just as a retry.  otherwise this is
 521                  * information that we should pass up to the upper-level driver
 522                  * so that we can deal with it there.
 523                  */
 524                 if (scmd->device->expecting_cc_ua) {
 525                         /*
 526                          * Because some device does not queue unit
 527                          * attentions correctly, we carefully check
 528                          * additional sense code and qualifier so as
 529                          * not to squash media change unit attention.
 530                          */
 531                         if (sshdr.asc != 0x28 || sshdr.ascq != 0x00) {
 532                                 scmd->device->expecting_cc_ua = 0;
 533                                 return NEEDS_RETRY;
 534                         }
 535                 }
 536                 /*
 537                  * we might also expect a cc/ua if another LUN on the target
 538                  * reported a UA with an ASC/ASCQ of 3F 0E -
 539                  * REPORTED LUNS DATA HAS CHANGED.
 540                  */
 541                 if (scmd->device->sdev_target->expecting_lun_change &&
 542                     sshdr.asc == 0x3f && sshdr.ascq == 0x0e)
 543                         return NEEDS_RETRY;
 544                 /*
 545                  * if the device is in the process of becoming ready, we
 546                  * should retry.
 547                  */
 548                 if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01))
 549                         return NEEDS_RETRY;
 550                 /*
 551                  * if the device is not started, we need to wake
 552                  * the error handler to start the motor
 553                  */
 554                 if (scmd->device->allow_restart &&
 555                     (sshdr.asc == 0x04) && (sshdr.ascq == 0x02))
 556                         return FAILED;
 557                 /*
 558                  * Pass the UA upwards for a determination in the completion
 559                  * functions.
 560                  */
 561                 return SUCCESS;
 562
 563                 /* these are not supported */
 564         case DATA_PROTECT:
 565                 if (sshdr.asc == 0x27 && sshdr.ascq == 0x07) {
 566                         /* Thin provisioning hard threshold reached */
 567                         set_host_byte(scmd, DID_ALLOC_FAILURE);
 568                         return SUCCESS;
 569                 }
 570         case COPY_ABORTED:
 571         case VOLUME_OVERFLOW:
 572         case MISCOMPARE:
 573         case BLANK_CHECK:
 574                 set_host_byte(scmd, DID_TARGET_FAILURE);
 575                 return SUCCESS;
 576
 577         case MEDIUM_ERROR:
 578                 if (sshdr.asc == 0x11 || /* UNRECOVERED READ ERR */
 579                     sshdr.asc == 0x13 || /* AMNF DATA FIELD */
 580                     sshdr.asc == 0x14) { /* RECORD NOT FOUND */
 581                         set_host_byte(scmd, DID_MEDIUM_ERROR);
 582                         return SUCCESS;
 583                 }
 584                 return NEEDS_RETRY;
 585
 586         case HARDWARE_ERROR:
 587                 if (scmd->device->retry_hwerror)
 588                         return ADD_TO_MLQUEUE;
 589                 else
 590                         set_host_byte(scmd, DID_TARGET_FAILURE);
 591
 592         case ILLEGAL_REQUEST:
 593                 if (sshdr.asc == 0x20 || /* Invalid command operation code */
 594                     sshdr.asc == 0x21 || /* Logical block address out of range */
 595                     sshdr.asc == 0x24 || /* Invalid field in cdb */
 596                     sshdr.asc == 0x26) { /* Parameter value invalid */
 597                         set_host_byte(scmd, DID_TARGET_FAILURE);
 598                 }
 599                 return SUCCESS;
 600
 601         default:
 602                 return SUCCESS;
 603         }
 604 }
 605 EXPORT_SYMBOL_GPL(scsi_check_sense);
 606
 607 static void scsi_handle_queue_ramp_up(struct scsi_device *sdev)
 608 {
 609         struct scsi_host_template *sht = sdev->host->hostt;
 610         struct scsi_device *tmp_sdev;
 611
 612         if (!sht->track_queue_depth ||
 613             sdev->queue_depth >= sdev->max_queue_depth)
 614                 return;
 615
 616         if (time_before(jiffies,
 617             sdev->last_queue_ramp_up + sdev->queue_ramp_up_period))
 618                 return;
 619
 620         if (time_before(jiffies,
 621             sdev->last_queue_full_time + sdev->queue_ramp_up_period))
 622                 return;
 623
 624         /*
 625          * Walk all devices of a target and do
 626          * ramp up on them.
 627          */
 628         shost_for_each_device(tmp_sdev, sdev->host) {
 629                 if (tmp_sdev->channel != sdev->channel ||
 630                     tmp_sdev->id != sdev->id ||
 631                     tmp_sdev->queue_depth == sdev->max_queue_depth)
 632                         continue;
 633
 634                 scsi_change_queue_depth(tmp_sdev, tmp_sdev->queue_depth + 1);
 635                 sdev->last_queue_ramp_up = jiffies;
 636         }
 637 }
 638
 639 static void scsi_handle_queue_full(struct scsi_device *sdev)
 640 {
 641         struct scsi_host_template *sht = sdev->host->hostt;
 642         struct scsi_device *tmp_sdev;
 643
 644         if (!sht->track_queue_depth)
 645                 return;
 646
 647         shost_for_each_device(tmp_sdev, sdev->host) {
 648                 if (tmp_sdev->channel != sdev->channel ||
 649                     tmp_sdev->id != sdev->id)
 650                         continue;
 651                 /*
 652                  * We do not know the number of commands that were at
 653                  * the device when we got the queue full so we start
 654                  * from the highest possible value and work our way down.
 655                  */
 656                 scsi_track_queue_full(tmp_sdev, tmp_sdev->queue_depth - 1);
 657         }
 658 }
 659
 660 /**
 661  * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD.
 662  * @scmd:       SCSI cmd to examine.
 663  *
 664  * Notes:
 665  *    This is *only* called when we are examining the status of commands
 666  *    queued during error recovery.  the main difference here is that we
 667  *    don't allow for the possibility of retries here, and we are a lot
 668  *    more restrictive about what we consider acceptable.
 669  */
 670 static int scsi_eh_completed_normally(struct scsi_cmnd *scmd)
 671 {
 672         /*
 673          * first check the host byte, to see if there is anything in there
 674          * that would indicate what we need to do.
 675          */
 676         if (host_byte(scmd->result) == DID_RESET) {
 677                 /*
 678                  * rats.  we are already in the error handler, so we now
 679                  * get to try and figure out what to do next.  if the sense
 680                  * is valid, we have a pretty good idea of what to do.
 681                  * if not, we mark it as FAILED.
 682                  */
 683                 return scsi_check_sense(scmd);
 684         }
 685         if (host_byte(scmd->result) != DID_OK)
 686                 return FAILED;
 687
 688         /*
 689          * next, check the message byte.
 690          */
 691         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
 692                 return FAILED;
 693
 694         /*
 695          * now, check the status byte to see if this indicates
 696          * anything special.
 697          */
 698         switch (status_byte(scmd->result)) {
 699         case GOOD:
 700                 scsi_handle_queue_ramp_up(scmd->device);
 701         case COMMAND_TERMINATED:
 702                 return SUCCESS;
 703         case CHECK_CONDITION:
 704                 return scsi_check_sense(scmd);
 705         case CONDITION_GOOD:
 706         case INTERMEDIATE_GOOD:
 707         case INTERMEDIATE_C_GOOD:
 708                 /*
 709                  * who knows?  FIXME(eric)
 710                  */
 711                 return SUCCESS;
 712         case RESERVATION_CONFLICT:
 713                 if (scmd->cmnd[0] == TEST_UNIT_READY)
 714                         /* it is a success, we probed the device and
 715                          * found it */
 716                         return SUCCESS;
 717                 /* otherwise, we failed to send the command */
 718                 return FAILED;
 719         case QUEUE_FULL:
 720                 scsi_handle_queue_full(scmd->device);
 721                 /* fall through */
 722         case BUSY:
 723                 return NEEDS_RETRY;
 724         default:
 725                 return FAILED;
 726         }
 727         return FAILED;
 728 }
 729
 730 /**
 731  * scsi_eh_done - Completion function for error handling.
 732  * @scmd:       Cmd that is done.
 733  */
 734 static void scsi_eh_done(struct scsi_cmnd *scmd)
 735 {
 736         struct completion *eh_action;
 737
 738         SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
 739                         "%s result: %x\n", __func__, scmd->result));
 740
 741         eh_action = scmd->device->host->eh_action;
 742         if (eh_action)
 743                 complete(eh_action);
 744 }
 745
 746 /**
 747  * scsi_try_host_reset - ask host adapter to reset itself
 748  * @scmd:       SCSI cmd to send host reset.
 749  */
 750 static int scsi_try_host_reset(struct scsi_cmnd *scmd)
 751 {
 752         unsigned long flags;
 753         int rtn;
 754         struct Scsi_Host *host = scmd->device->host;
 755         struct scsi_host_template *hostt = host->hostt;
 756
 757         SCSI_LOG_ERROR_RECOVERY(3,
 758                 shost_printk(KERN_INFO, host, "Snd Host RST\n"));
 759
 760         if (!hostt->eh_host_reset_handler)
 761                 return FAILED;
 762
 763         rtn = hostt->eh_host_reset_handler(scmd);
 764
 765         if (rtn == SUCCESS) {
 766                 if (!hostt->skip_settle_delay)
 767                         ssleep(HOST_RESET_SETTLE_TIME);
 768                 spin_lock_irqsave(host->host_lock, flags);
 769                 scsi_report_bus_reset(host, scmd_channel(scmd));
 770                 spin_unlock_irqrestore(host->host_lock, flags);
 771         }
 772
 773         return rtn;
 774 }
 775
 776 /**
 777  * scsi_try_bus_reset - ask host to perform a bus reset
 778  * @scmd:       SCSI cmd to send bus reset.
 779  */
 780 static int scsi_try_bus_reset(struct scsi_cmnd *scmd)
 781 {
 782         unsigned long flags;
 783         int rtn;
 784         struct Scsi_Host *host = scmd->device->host;
 785         struct scsi_host_template *hostt = host->hostt;
 786
 787         SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
 788                 "%s: Snd Bus RST\n", __func__));
 789
 790         if (!hostt->eh_bus_reset_handler)
 791                 return FAILED;
 792
 793         rtn = hostt->eh_bus_reset_handler(scmd);
 794
 795         if (rtn == SUCCESS) {
 796                 if (!hostt->skip_settle_delay)
 797                         ssleep(BUS_RESET_SETTLE_TIME);
 798                 spin_lock_irqsave(host->host_lock, flags);
 799                 scsi_report_bus_reset(host, scmd_channel(scmd));
 800                 spin_unlock_irqrestore(host->host_lock, flags);
 801         }
 802
 803         return rtn;
 804 }
 805
 806 static void __scsi_report_device_reset(struct scsi_device *sdev, void *data)
 807 {
 808         sdev->was_reset = 1;
 809         sdev->expecting_cc_ua = 1;
 810 }
 811
 812 /**
 813  * scsi_try_target_reset - Ask host to perform a target reset
 814  * @scmd:       SCSI cmd used to send a target reset
 815  *
 816  * Notes:
 817  *    There is no timeout for this operation.  if this operation is
 818  *    unreliable for a given host, then the host itself needs to put a
 819  *    timer on it, and set the host back to a consistent state prior to
 820  *    returning.
 821  */
 822 static int scsi_try_target_reset(struct scsi_cmnd *scmd)
 823 {
 824         unsigned long flags;
 825         int rtn;
 826         struct Scsi_Host *host = scmd->device->host;
 827         struct scsi_host_template *hostt = host->hostt;
 828
 829         if (!hostt->eh_target_reset_handler)
 830                 return FAILED;
 831
 832         rtn = hostt->eh_target_reset_handler(scmd);
 833         if (rtn == SUCCESS) {
 834                 spin_lock_irqsave(host->host_lock, flags);
 835                 __starget_for_each_device(scsi_target(scmd->device), NULL,
 836                                           __scsi_report_device_reset);
 837                 spin_unlock_irqrestore(host->host_lock, flags);
 838         }
 839
 840         return rtn;
 841 }
 842
 843 /**
 844  * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
 845  * @scmd:       SCSI cmd used to send BDR
 846  *
 847  * Notes:
 848  *    There is no timeout for this operation.  if this operation is
 849  *    unreliable for a given host, then the host itself needs to put a
 850  *    timer on it, and set the host back to a consistent state prior to
 851  *    returning.
 852  */
 853 static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
 854 {
 855         int rtn;
 856         struct scsi_host_template *hostt = scmd->device->host->hostt;
 857
 858         if (!hostt->eh_device_reset_handler)
 859                 return FAILED;
 860
 861         rtn = hostt->eh_device_reset_handler(scmd);
 862         if (rtn == SUCCESS)
 863                 __scsi_report_device_reset(scmd->device, NULL);
 864         return rtn;
 865 }
 866
 867 /**
 868  * scsi_try_to_abort_cmd - Ask host to abort a SCSI command
 869  * @hostt:      SCSI driver host template
 870  * @scmd:       SCSI cmd used to send a target reset
 871  *
 872  * Return value:
 873  *      SUCCESS, FAILED, or FAST_IO_FAIL
 874  *
 875  * Notes:
 876  *    SUCCESS does not necessarily indicate that the command
 877  *    has been aborted; it only indicates that the LLDDs
 878  *    has cleared all references to that command.
 879  *    LLDDs should return FAILED only if an abort was required
 880  *    but could not be executed. LLDDs should return FAST_IO_FAIL
 881  *    if the device is temporarily unavailable (eg due to a
 882  *    link down on FibreChannel)
 883  */
 884 static int scsi_try_to_abort_cmd(struct scsi_host_template *hostt,
 885                                  struct scsi_cmnd *scmd)
 886 {
 887         if (!hostt->eh_abort_handler)
 888                 return FAILED;
 889
 890         return hostt->eh_abort_handler(scmd);
 891 }
 892
 893 static void scsi_abort_eh_cmnd(struct scsi_cmnd *scmd)
 894 {
 895         if (scsi_try_to_abort_cmd(scmd->device->host->hostt, scmd) != SUCCESS)
 896                 if (scsi_try_bus_device_reset(scmd) != SUCCESS)
 897                         if (scsi_try_target_reset(scmd) != SUCCESS)
 898                                 if (scsi_try_bus_reset(scmd) != SUCCESS)
 899                                         scsi_try_host_reset(scmd);
 900 }
 901
 902 /**
 903  * scsi_eh_prep_cmnd  - Save a scsi command info as part of error recovery
 904  * @scmd:       SCSI command structure to hijack
 905  * @ses:        structure to save restore information
 906  * @cmnd:       CDB to send. Can be NULL if no new cmnd is needed
 907  * @cmnd_size:  size in bytes of @cmnd (must be <= BLK_MAX_CDB)
 908  * @sense_bytes: size of sense data to copy. or 0 (if != 0 @cmnd is ignored)
 909  *
 910  * This function is used to save a scsi command information before re-execution
 911  * as part of the error recovery process.  If @sense_bytes is 0 the command
 912  * sent must be one that does not transfer any data.  If @sense_bytes != 0
 913  * @cmnd is ignored and this functions sets up a REQUEST_SENSE command
 914  * and cmnd buffers to read @sense_bytes into @scmd->sense_buffer.
 915  */
 916 void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses,
 917                         unsigned char *cmnd, int cmnd_size, unsigned sense_bytes)
 918 {
 919         struct scsi_device *sdev = scmd->device;
 920
 921         /*
 922          * We need saved copies of a number of fields - this is because
 923          * error handling may need to overwrite these with different values
 924          * to run different commands, and once error handling is complete,
 925          * we will need to restore these values prior to running the actual
 926          * command.
 927          */
 928         ses->cmd_len = scmd->cmd_len;
 929         ses->cmnd = scmd->cmnd;
 930         ses->data_direction = scmd->sc_data_direction;
 931         ses->sdb = scmd->sdb;
 932         ses->next_rq = scmd->request->next_rq;
 933         ses->result = scmd->result;
 934         ses->underflow = scmd->underflow;
 935         ses->prot_op = scmd->prot_op;
 936
 937         scmd->prot_op = SCSI_PROT_NORMAL;
 938         scmd->eh_eflags = 0;
 939         scmd->cmnd = ses->eh_cmnd;
 940         memset(scmd->cmnd, 0, BLK_MAX_CDB);
 941         memset(&scmd->sdb, 0, sizeof(scmd->sdb));
 942         scmd->request->next_rq = NULL;
 943         scmd->result = 0;
 944
 945         if (sense_bytes) {
 946                 scmd->sdb.length = min_t(unsigned, SCSI_SENSE_BUFFERSIZE,
 947                                          sense_bytes);
 948                 sg_init_one(&ses->sense_sgl, scmd->sense_buffer,
 949                             scmd->sdb.length);
 950                 scmd->sdb.table.sgl = &ses->sense_sgl;
 951                 scmd->sc_data_direction = DMA_FROM_DEVICE;
 952                 scmd->sdb.table.nents = scmd->sdb.table.orig_nents = 1;
 953                 scmd->cmnd[0] = REQUEST_SENSE;
 954                 scmd->cmnd[4] = scmd->sdb.length;
 955                 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
 956         } else {
 957                 scmd->sc_data_direction = DMA_NONE;
 958                 if (cmnd) {
 959                         BUG_ON(cmnd_size > BLK_MAX_CDB);
 960                         memcpy(scmd->cmnd, cmnd, cmnd_size);
 961                         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
 962                 }
 963         }
 964
 965         scmd->underflow = 0;
 966
 967         if (sdev->scsi_level <= SCSI_2 && sdev->scsi_level != SCSI_UNKNOWN)
 968                 scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
 969                         (sdev->lun << 5 & 0xe0);
 970
 971         /*
 972          * Zero the sense buffer.  The scsi spec mandates that any
 973          * untransferred sense data should be interpreted as being zero.
 974          */
 975         memset(scmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
 976 }
 977 EXPORT_SYMBOL(scsi_eh_prep_cmnd);
 978
 979 /**
 980  * scsi_eh_restore_cmnd  - Restore a scsi command info as part of error recovery
 981  * @scmd:       SCSI command structure to restore
 982  * @ses:        saved information from a coresponding call to scsi_eh_prep_cmnd
 983  *
 984  * Undo any damage done by above scsi_eh_prep_cmnd().
 985  */
 986 void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct scsi_eh_save *ses)
 987 {
 988         /*
 989          * Restore original data
 990          */
 991         scmd->cmd_len = ses->cmd_len;
 992         scmd->cmnd = ses->cmnd;
 993         scmd->sc_data_direction = ses->data_direction;
 994         scmd->sdb = ses->sdb;
 995         scmd->request->next_rq = ses->next_rq;
 996         scmd->result = ses->result;
 997         scmd->underflow = ses->underflow;
 998         scmd->prot_op = ses->prot_op;
 999 }
1000 EXPORT_SYMBOL(scsi_eh_restore_cmnd);
1001
1002 /**
1003  * scsi_send_eh_cmnd  - submit a scsi command as part of error recovery
1004  * @scmd:       SCSI command structure to hijack
1005  * @cmnd:       CDB to send
1006  * @cmnd_size:  size in bytes of @cmnd
1007  * @timeout:    timeout for this request
1008  * @sense_bytes: size of sense data to copy or 0
1009  *
1010  * This function is used to send a scsi command down to a target device
1011  * as part of the error recovery process. See also scsi_eh_prep_cmnd() above.
1012  *
1013  * Return value:
1014  *    SUCCESS or FAILED or NEEDS_RETRY
1015  */
1016 static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd,
1017                              int cmnd_size, int timeout, unsigned sense_bytes)
1018 {
1019         struct scsi_device *sdev = scmd->device;
1020         struct Scsi_Host *shost = sdev->host;
1021         DECLARE_COMPLETION_ONSTACK(done);
1022         unsigned long timeleft = timeout;
1023         struct scsi_eh_save ses;
1024         const unsigned long stall_for = msecs_to_jiffies(100);
1025         int rtn;
1026
1027 retry:
1028         scsi_eh_prep_cmnd(scmd, &ses, cmnd, cmnd_size, sense_bytes);
1029         shost->eh_action = &done;
1030
1031         scsi_log_send(scmd);
1032         scmd->scsi_done = scsi_eh_done;
1033         rtn = shost->hostt->queuecommand(shost, scmd);
1034         if (rtn) {
1035                 if (timeleft > stall_for) {
1036                         scsi_eh_restore_cmnd(scmd, &ses);
1037                         timeleft -= stall_for;
1038                         msleep(jiffies_to_msecs(stall_for));
1039                         goto retry;
1040                 }
1041                 /* signal not to enter either branch of the if () below */
1042                 timeleft = 0;
1043                 rtn = FAILED;
1044         } else {
1045                 timeleft = wait_for_completion_timeout(&done, timeout);
1046                 rtn = SUCCESS;
1047         }
1048
1049         shost->eh_action = NULL;
1050
1051         scsi_log_completion(scmd, rtn);
1052
1053         SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1054                         "%s timeleft: %ld\n",
1055                         __func__, timeleft));
1056
1057         /*
1058          * If there is time left scsi_eh_done got called, and we will examine
1059          * the actual status codes to see whether the command actually did
1060          * complete normally, else if we have a zero return and no time left,
1061          * the command must still be pending, so abort it and return FAILED.
1062          * If we never actually managed to issue the command, because
1063          * ->queuecommand() kept returning non zero, use the rtn = FAILED
1064          * value above (so don't execute either branch of the if)
1065          */
1066         if (timeleft) {
1067                 rtn = scsi_eh_completed_normally(scmd);
1068                 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1069                         "%s: scsi_eh_completed_normally %x\n", __func__, rtn));
1070
1071                 switch (rtn) {
1072                 case SUCCESS:
1073                 case NEEDS_RETRY:
1074                 case FAILED:
1075                         break;
1076                 case ADD_TO_MLQUEUE:
1077                         rtn = NEEDS_RETRY;
1078                         break;
1079                 default:
1080                         rtn = FAILED;
1081                         break;
1082                 }
1083         } else if (rtn != FAILED) {
1084                 scsi_abort_eh_cmnd(scmd);
1085                 rtn = FAILED;
1086         }
1087
1088         scsi_eh_restore_cmnd(scmd, &ses);
1089
1090         return rtn;
1091 }
1092
1093 /**
1094  * scsi_request_sense - Request sense data from a particular target.
1095  * @scmd:       SCSI cmd for request sense.
1096  *
1097  * Notes:
1098  *    Some hosts automatically obtain this information, others require
1099  *    that we obtain it on our own. This function will *not* return until
1100  *    the command either times out, or it completes.
1101  */
1102 static int scsi_request_sense(struct scsi_cmnd *scmd)
1103 {
1104         return scsi_send_eh_cmnd(scmd, NULL, 0, scmd->device->eh_timeout, ~0);
1105 }
1106
1107 static int scsi_eh_action(struct scsi_cmnd *scmd, int rtn)
1108 {
1109         if (scmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
1110                 struct scsi_driver *sdrv = scsi_cmd_to_driver(scmd);
1111                 if (sdrv->eh_action)
1112                         rtn = sdrv->eh_action(scmd, rtn);
1113         }
1114         return rtn;
1115 }
1116
1117 /**
1118  * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
1119  * @scmd:       Original SCSI cmd that eh has finished.
1120  * @done_q:     Queue for processed commands.
1121  *
1122  * Notes:
1123  *    We don't want to use the normal command completion while we are are
1124  *    still handling errors - it may cause other commands to be queued,
1125  *    and that would disturb what we are doing.  Thus we really want to
1126  *    keep a list of pending commands for final completion, and once we
1127  *    are ready to leave error handling we handle completion for real.
1128  */
1129 void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)
1130 {
1131         scmd->eh_eflags = 0;
1132         list_move_tail(&scmd->eh_entry, done_q);
1133 }
1134 EXPORT_SYMBOL(scsi_eh_finish_cmd);
1135
1136 /**
1137  * scsi_eh_get_sense - Get device sense data.
1138  * @work_q:     Queue of commands to process.
1139  * @done_q:     Queue of processed commands.
1140  *
1141  * Description:
1142  *    See if we need to request sense information.  if so, then get it
1143  *    now, so we have a better idea of what to do.
1144  *
1145  * Notes:
1146  *    This has the unfortunate side effect that if a shost adapter does
1147  *    not automatically request sense information, we end up shutting
1148  *    it down before we request it.
1149  *
1150  *    All drivers should request sense information internally these days,
1151  *    so for now all I have to say is tough noogies if you end up in here.
1152  *
1153  *    XXX: Long term this code should go away, but that needs an audit of
1154  *         all LLDDs first.
1155  */
1156 int scsi_eh_get_sense(struct list_head *work_q,
1157                       struct list_head *done_q)
1158 {
1159         struct scsi_cmnd *scmd, *next;
1160         struct Scsi_Host *shost;
1161         int rtn;
1162
1163         /*
1164          * If SCSI_EH_ABORT_SCHEDULED has been set, it is timeout IO,
1165          * should not get sense.
1166          */
1167         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1168                 if ((scmd->eh_eflags & SCSI_EH_CANCEL_CMD) ||
1169                     (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) ||
1170                     SCSI_SENSE_VALID(scmd))
1171                         continue;
1172
1173                 shost = scmd->device->host;
1174                 if (scsi_host_eh_past_deadline(shost)) {
1175                         SCSI_LOG_ERROR_RECOVERY(3,
1176                                 scmd_printk(KERN_INFO, scmd,
1177                                             "%s: skip request sense, past eh deadline\n",
1178                                              current->comm));
1179                         break;
1180                 }
1181                 if (status_byte(scmd->result) != CHECK_CONDITION)
1182                         /*
1183                          * don't request sense if there's no check condition
1184                          * status because the error we're processing isn't one
1185                          * that has a sense code (and some devices get
1186                          * confused by sense requests out of the blue)
1187                          */
1188                         continue;
1189
1190                 SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd,
1191                                                   "%s: requesting sense\n",
1192                                                   current->comm));
1193                 rtn = scsi_request_sense(scmd);
1194                 if (rtn != SUCCESS)
1195                         continue;
1196
1197                 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1198                         "sense requested, result %x\n", scmd->result));
1199                 SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense(scmd));
1200
1201                 rtn = scsi_decide_disposition(scmd);
1202
1203                 /*
1204                  * if the result was normal, then just pass it along to the
1205                  * upper level.
1206                  */
1207                 if (rtn == SUCCESS)
1208                         /* we don't want this command reissued, just
1209                          * finished with the sense data, so set
1210                          * retries to the max allowed to ensure it
1211                          * won't get reissued */
1212                         scmd->retries = scmd->allowed;
1213                 else if (rtn != NEEDS_RETRY)
1214                         continue;
1215
1216                 scsi_eh_finish_cmd(scmd, done_q);
1217         }
1218
1219         return list_empty(work_q);
1220 }
1221 EXPORT_SYMBOL_GPL(scsi_eh_get_sense);
1222
1223 /**
1224  * scsi_eh_tur - Send TUR to device.
1225  * @scmd:       &scsi_cmnd to send TUR
1226  *
1227  * Return value:
1228  *    0 - Device is ready. 1 - Device NOT ready.
1229  */
1230 static int scsi_eh_tur(struct scsi_cmnd *scmd)
1231 {
1232         static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
1233         int retry_cnt = 1, rtn;
1234
1235 retry_tur:
1236         rtn = scsi_send_eh_cmnd(scmd, tur_command, 6,
1237                                 scmd->device->eh_timeout, 0);
1238
1239         SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1240                 "%s return: %x\n", __func__, rtn));
1241
1242         switch (rtn) {
1243         case NEEDS_RETRY:
1244                 if (retry_cnt--)
1245                         goto retry_tur;
1246                 /*FALLTHRU*/
1247         case SUCCESS:
1248                 return 0;
1249         default:
1250                 return 1;
1251         }
1252 }
1253
1254 /**
1255  * scsi_eh_test_devices - check if devices are responding from error recovery.
1256  * @cmd_list:   scsi commands in error recovery.
1257  * @work_q:     queue for commands which still need more error recovery
1258  * @done_q:     queue for commands which are finished
1259  * @try_stu:    boolean on if a STU command should be tried in addition to TUR.
1260  *
1261  * Decription:
1262  *    Tests if devices are in a working state.  Commands to devices now in
1263  *    a working state are sent to the done_q while commands to devices which
1264  *    are still failing to respond are returned to the work_q for more
1265  *    processing.
1266  **/
1267 static int scsi_eh_test_devices(struct list_head *cmd_list,
1268                                 struct list_head *work_q,
1269                                 struct list_head *done_q, int try_stu)
1270 {
1271         struct scsi_cmnd *scmd, *next;
1272         struct scsi_device *sdev;
1273         int finish_cmds;
1274
1275         while (!list_empty(cmd_list)) {
1276                 scmd = list_entry(cmd_list->next, struct scsi_cmnd, eh_entry);
1277                 sdev = scmd->device;
1278
1279                 if (!try_stu) {
1280                         if (scsi_host_eh_past_deadline(sdev->host)) {
1281                                 /* Push items back onto work_q */
1282                                 list_splice_init(cmd_list, work_q);
1283                                 SCSI_LOG_ERROR_RECOVERY(3,
1284                                         sdev_printk(KERN_INFO, sdev,
1285                                                     "%s: skip test device, past eh deadline",
1286                                                     current->comm));
1287                                 break;
1288                         }
1289                 }
1290
1291                 finish_cmds = !scsi_device_online(scmd->device) ||
1292                         (try_stu && !scsi_eh_try_stu(scmd) &&
1293                          !scsi_eh_tur(scmd)) ||
1294                         !scsi_eh_tur(scmd);
1295
1296                 list_for_each_entry_safe(scmd, next, cmd_list, eh_entry)
1297                         if (scmd->device == sdev) {
1298                                 if (finish_cmds &&
1299                                     (try_stu ||
1300                                      scsi_eh_action(scmd, SUCCESS) == SUCCESS))
1301                                         scsi_eh_finish_cmd(scmd, done_q);
1302                                 else
1303                                         list_move_tail(&scmd->eh_entry, work_q);
1304                         }
1305         }
1306         return list_empty(work_q);
1307 }
1308
1309
1310 /**
1311  * scsi_eh_abort_cmds - abort pending commands.
1312  * @work_q:     &list_head for pending commands.
1313  * @done_q:     &list_head for processed commands.
1314  *
1315  * Decription:
1316  *    Try and see whether or not it makes sense to try and abort the
1317  *    running command.  This only works out to be the case if we have one
1318  *    command that has timed out.  If the command simply failed, it makes
1319  *    no sense to try and abort the command, since as far as the shost
1320  *    adapter is concerned, it isn't running.
1321  */
1322 static int scsi_eh_abort_cmds(struct list_head *work_q,
1323                               struct list_head *done_q)
1324 {
1325         struct scsi_cmnd *scmd, *next;
1326         LIST_HEAD(check_list);
1327         int rtn;
1328         struct Scsi_Host *shost;
1329
1330         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1331                 if (!(scmd->eh_eflags & SCSI_EH_CANCEL_CMD))
1332                         continue;
1333                 shost = scmd->device->host;
1334                 if (scsi_host_eh_past_deadline(shost)) {
1335                         list_splice_init(&check_list, work_q);
1336                         SCSI_LOG_ERROR_RECOVERY(3,
1337                                 scmd_printk(KERN_INFO, scmd,
1338                                             "%s: skip aborting cmd, past eh deadline\n",
1339                                             current->comm));
1340                         return list_empty(work_q);
1341                 }
1342                 SCSI_LOG_ERROR_RECOVERY(3,
1343                         scmd_printk(KERN_INFO, scmd,
1344                                      "%s: aborting cmd\n", current->comm));
1345                 rtn = scsi_try_to_abort_cmd(shost->hostt, scmd);
1346                 if (rtn == FAILED) {
1347                         SCSI_LOG_ERROR_RECOVERY(3,
1348                                 scmd_printk(KERN_INFO, scmd,
1349                                             "%s: aborting cmd failed\n",
1350                                              current->comm));
1351                         list_splice_init(&check_list, work_q);
1352                         return list_empty(work_q);
1353                 }
1354                 scmd->eh_eflags &= ~SCSI_EH_CANCEL_CMD;
1355                 if (rtn == FAST_IO_FAIL)
1356                         scsi_eh_finish_cmd(scmd, done_q);
1357                 else
1358                         list_move_tail(&scmd->eh_entry, &check_list);
1359         }
1360
1361         return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1362 }
1363
1364 /**
1365  * scsi_eh_try_stu - Send START_UNIT to device.
1366  * @scmd:       &scsi_cmnd to send START_UNIT
1367  *
1368  * Return value:
1369  *    0 - Device is ready. 1 - Device NOT ready.
1370  */
1371 static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
1372 {
1373         static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
1374
1375         if (scmd->device->allow_restart) {
1376                 int i, rtn = NEEDS_RETRY;
1377
1378                 for (i = 0; rtn == NEEDS_RETRY && i < 2; i++)
1379                         rtn = scsi_send_eh_cmnd(scmd, stu_command, 6, scmd->device->request_queue->rq_timeout, 0);
1380
1381                 if (rtn == SUCCESS)
1382                         return 0;
1383         }
1384
1385         return 1;
1386 }
1387
1388  /**
1389  * scsi_eh_stu - send START_UNIT if needed
1390  * @shost:      &scsi host being recovered.
1391  * @work_q:     &list_head for pending commands.
1392  * @done_q:     &list_head for processed commands.
1393  *
1394  * Notes:
1395  *    If commands are failing due to not ready, initializing command required,
1396  *      try revalidating the device, which will end up sending a start unit.
1397  */
1398 static int scsi_eh_stu(struct Scsi_Host *shost,
1399                               struct list_head *work_q,
1400                               struct list_head *done_q)
1401 {
1402         struct scsi_cmnd *scmd, *stu_scmd, *next;
1403         struct scsi_device *sdev;
1404
1405         shost_for_each_device(sdev, shost) {
1406                 if (scsi_host_eh_past_deadline(shost)) {
1407                         SCSI_LOG_ERROR_RECOVERY(3,
1408                                 sdev_printk(KERN_INFO, sdev,
1409                                             "%s: skip START_UNIT, past eh deadline\n",
1410                                             current->comm));
1411                         break;
1412                 }
1413                 stu_scmd = NULL;
1414                 list_for_each_entry(scmd, work_q, eh_entry)
1415                         if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
1416                             scsi_check_sense(scmd) == FAILED ) {
1417                                 stu_scmd = scmd;
1418                                 break;
1419                         }
1420
1421                 if (!stu_scmd)
1422                         continue;
1423
1424                 SCSI_LOG_ERROR_RECOVERY(3,
1425                         sdev_printk(KERN_INFO, sdev,
1426                                      "%s: Sending START_UNIT\n",
1427                                     current->comm));
1428
1429                 if (!scsi_eh_try_stu(stu_scmd)) {
1430                         if (!scsi_device_online(sdev) ||
1431                             !scsi_eh_tur(stu_scmd)) {
1432                                 list_for_each_entry_safe(scmd, next,
1433                                                           work_q, eh_entry) {
1434                                         if (scmd->device == sdev &&
1435                                             scsi_eh_action(scmd, SUCCESS) == SUCCESS)
1436                                                 scsi_eh_finish_cmd(scmd, done_q);
1437                                 }
1438                         }
1439                 } else {
1440                         SCSI_LOG_ERROR_RECOVERY(3,
1441                                 sdev_printk(KERN_INFO, sdev,
1442                                             "%s: START_UNIT failed\n",
1443                                             current->comm));
1444                 }
1445         }
1446
1447         return list_empty(work_q);
1448 }
1449
1450
1451 /**
1452  * scsi_eh_bus_device_reset - send bdr if needed
1453  * @shost:      scsi host being recovered.
1454  * @work_q:     &list_head for pending commands.
1455  * @done_q:     &list_head for processed commands.
1456  *
1457  * Notes:
1458  *    Try a bus device reset.  Still, look to see whether we have multiple
1459  *    devices that are jammed or not - if we have multiple devices, it
1460  *    makes no sense to try bus_device_reset - we really would need to try
1461  *    a bus_reset instead.
1462  */
1463 static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
1464                                     struct list_head *work_q,
1465                                     struct list_head *done_q)
1466 {
1467         struct scsi_cmnd *scmd, *bdr_scmd, *next;
1468         struct scsi_device *sdev;
1469         int rtn;
1470
1471         shost_for_each_device(sdev, shost) {
1472                 if (scsi_host_eh_past_deadline(shost)) {
1473                         SCSI_LOG_ERROR_RECOVERY(3,
1474                                 sdev_printk(KERN_INFO, sdev,
1475                                             "%s: skip BDR, past eh deadline\n",
1476                                              current->comm));
1477                         break;
1478                 }
1479                 bdr_scmd = NULL;
1480                 list_for_each_entry(scmd, work_q, eh_entry)
1481                         if (scmd->device == sdev) {
1482                                 bdr_scmd = scmd;
1483                                 break;
1484                         }
1485
1486                 if (!bdr_scmd)
1487                         continue;
1488
1489                 SCSI_LOG_ERROR_RECOVERY(3,
1490                         sdev_printk(KERN_INFO, sdev,
1491                                      "%s: Sending BDR\n", current->comm));
1492                 rtn = scsi_try_bus_device_reset(bdr_scmd);
1493                 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1494                         if (!scsi_device_online(sdev) ||
1495                             rtn == FAST_IO_FAIL ||
1496                             !scsi_eh_tur(bdr_scmd)) {
1497                                 list_for_each_entry_safe(scmd, next,
1498                                                          work_q, eh_entry) {
1499                                         if (scmd->device == sdev &&
1500                                             scsi_eh_action(scmd, rtn) != FAILED)
1501                                                 scsi_eh_finish_cmd(scmd,
1502                                                                    done_q);
1503                                 }
1504                         }
1505                 } else {
1506                         SCSI_LOG_ERROR_RECOVERY(3,
1507                                 sdev_printk(KERN_INFO, sdev,
1508                                             "%s: BDR failed\n", current->comm));
1509                 }
1510         }
1511
1512         return list_empty(work_q);
1513 }
1514
1515 /**
1516  * scsi_eh_target_reset - send target reset if needed
1517  * @shost:      scsi host being recovered.
1518  * @work_q:     &list_head for pending commands.
1519  * @done_q:     &list_head for processed commands.
1520  *
1521  * Notes:
1522  *    Try a target reset.
1523  */
1524 static int scsi_eh_target_reset(struct Scsi_Host *shost,
1525                                 struct list_head *work_q,
1526                                 struct list_head *done_q)
1527 {
1528         LIST_HEAD(tmp_list);
1529         LIST_HEAD(check_list);
1530
1531         list_splice_init(work_q, &tmp_list);
1532
1533         while (!list_empty(&tmp_list)) {
1534                 struct scsi_cmnd *next, *scmd;
1535                 int rtn;
1536                 unsigned int id;
1537
1538                 if (scsi_host_eh_past_deadline(shost)) {
1539                         /* push back on work queue for further processing */
1540                         list_splice_init(&check_list, work_q);
1541                         list_splice_init(&tmp_list, work_q);
1542                         SCSI_LOG_ERROR_RECOVERY(3,
1543                                 shost_printk(KERN_INFO, shost,
1544                                             "%s: Skip target reset, past eh deadline\n",
1545                                              current->comm));
1546                         return list_empty(work_q);
1547                 }
1548
1549                 scmd = list_entry(tmp_list.next, struct scsi_cmnd, eh_entry);
1550                 id = scmd_id(scmd);
1551
1552                 SCSI_LOG_ERROR_RECOVERY(3,
1553                         shost_printk(KERN_INFO, shost,
1554                                      "%s: Sending target reset to target %d\n",
1555                                      current->comm, id));
1556                 rtn = scsi_try_target_reset(scmd);
1557                 if (rtn != SUCCESS && rtn != FAST_IO_FAIL)
1558                         SCSI_LOG_ERROR_RECOVERY(3,
1559                                 shost_printk(KERN_INFO, shost,
1560                                              "%s: Target reset failed"
1561                                              " target: %d\n",
1562                                              current->comm, id));
1563                 list_for_each_entry_safe(scmd, next, &tmp_list, eh_entry) {
1564                         if (scmd_id(scmd) != id)
1565                                 continue;
1566
1567                         if (rtn == SUCCESS)
1568                                 list_move_tail(&scmd->eh_entry, &check_list);
1569                         else if (rtn == FAST_IO_FAIL)
1570                                 scsi_eh_finish_cmd(scmd, done_q);
1571                         else
1572                                 /* push back on work queue for further processing */
1573                                 list_move(&scmd->eh_entry, work_q);
1574                 }
1575         }
1576
1577         return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1578 }
1579
1580 /**
1581  * scsi_eh_bus_reset - send a bus reset
1582  * @shost:      &scsi host being recovered.
1583  * @work_q:     &list_head for pending commands.
1584  * @done_q:     &list_head for processed commands.
1585  */
1586 static int scsi_eh_bus_reset(struct Scsi_Host *shost,
1587                              struct list_head *work_q,
1588                              struct list_head *done_q)
1589 {
1590         struct scsi_cmnd *scmd, *chan_scmd, *next;
1591         LIST_HEAD(check_list);
1592         unsigned int channel;
1593         int rtn;
1594
1595         /*
1596          * we really want to loop over the various channels, and do this on
1597          * a channel by channel basis.  we should also check to see if any
1598          * of the failed commands are on soft_reset devices, and if so, skip
1599          * the reset.
1600          */
1601
1602         for (channel = 0; channel <= shost->max_channel; channel++) {
1603                 if (scsi_host_eh_past_deadline(shost)) {
1604                         list_splice_init(&check_list, work_q);
1605                         SCSI_LOG_ERROR_RECOVERY(3,
1606                                 shost_printk(KERN_INFO, shost,
1607                                             "%s: skip BRST, past eh deadline\n",
1608                                              current->comm));
1609                         return list_empty(work_q);
1610                 }
1611
1612                 chan_scmd = NULL;
1613                 list_for_each_entry(scmd, work_q, eh_entry) {
1614                         if (channel == scmd_channel(scmd)) {
1615                                 chan_scmd = scmd;
1616                                 break;
1617                                 /*
1618                                  * FIXME add back in some support for
1619                                  * soft_reset devices.
1620                                  */
1621                         }
1622                 }
1623
1624                 if (!chan_scmd)
1625                         continue;
1626                 SCSI_LOG_ERROR_RECOVERY(3,
1627                         shost_printk(KERN_INFO, shost,
1628                                      "%s: Sending BRST chan: %d\n",
1629                                      current->comm, channel));
1630                 rtn = scsi_try_bus_reset(chan_scmd);
1631                 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1632                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1633                                 if (channel == scmd_channel(scmd)) {
1634                                         if (rtn == FAST_IO_FAIL)
1635                                                 scsi_eh_finish_cmd(scmd,
1636                                                                    done_q);
1637                                         else
1638                                                 list_move_tail(&scmd->eh_entry,
1639                                                                &check_list);
1640                                 }
1641                         }
1642                 } else {
1643                         SCSI_LOG_ERROR_RECOVERY(3,
1644                                 shost_printk(KERN_INFO, shost,
1645                                              "%s: BRST failed chan: %d\n",
1646                                              current->comm, channel));
1647                 }
1648         }
1649         return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1650 }
1651
1652 /**
1653  * scsi_eh_host_reset - send a host reset
1654  * @shost:      host to be reset.
1655  * @work_q:     &list_head for pending commands.
1656  * @done_q:     &list_head for processed commands.
1657  */
1658 static int scsi_eh_host_reset(struct Scsi_Host *shost,
1659                               struct list_head *work_q,
1660                               struct list_head *done_q)
1661 {
1662         struct scsi_cmnd *scmd, *next;
1663         LIST_HEAD(check_list);
1664         int rtn;
1665
1666         if (!list_empty(work_q)) {
1667                 scmd = list_entry(work_q->next,
1668                                   struct scsi_cmnd, eh_entry);
1669
1670                 SCSI_LOG_ERROR_RECOVERY(3,
1671                         shost_printk(KERN_INFO, shost,
1672                                      "%s: Sending HRST\n",
1673                                      current->comm));
1674
1675                 rtn = scsi_try_host_reset(scmd);
1676                 if (rtn == SUCCESS) {
1677                         list_splice_init(work_q, &check_list);
1678                 } else if (rtn == FAST_IO_FAIL) {
1679                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1680                                         scsi_eh_finish_cmd(scmd, done_q);
1681                         }
1682                 } else {
1683                         SCSI_LOG_ERROR_RECOVERY(3,
1684                                 shost_printk(KERN_INFO, shost,
1685                                              "%s: HRST failed\n",
1686                                              current->comm));
1687                 }
1688         }
1689         return scsi_eh_test_devices(&check_list, work_q, done_q, 1);
1690 }
1691
1692 /**
1693  * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
1694  * @work_q:     &list_head for pending commands.
1695  * @done_q:     &list_head for processed commands.
1696  */
1697 static void scsi_eh_offline_sdevs(struct list_head *work_q,
1698                                   struct list_head *done_q)
1699 {
1700         struct scsi_cmnd *scmd, *next;
1701
1702         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1703                 sdev_printk(KERN_INFO, scmd->device, "Device offlined - "
1704                             "not ready after error recovery\n");
1705                 scsi_device_set_state(scmd->device, SDEV_OFFLINE);
1706                 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD) {
1707                         /*
1708                          * FIXME: Handle lost cmds.
1709                          */
1710                 }
1711                 scsi_eh_finish_cmd(scmd, done_q);
1712         }
1713         return;
1714 }
1715
1716 /**
1717  * scsi_noretry_cmd - determine if command should be failed fast
1718  * @scmd:       SCSI cmd to examine.
1719  */
1720 int scsi_noretry_cmd(struct scsi_cmnd *scmd)
1721 {
1722         switch (host_byte(scmd->result)) {
1723         case DID_OK:
1724                 break;
1725         case DID_TIME_OUT:
1726                 goto check_type;
1727         case DID_BUS_BUSY:
1728                 return (scmd->request->cmd_flags & REQ_FAILFAST_TRANSPORT);
1729         case DID_PARITY:
1730                 return (scmd->request->cmd_flags & REQ_FAILFAST_DEV);
1731         case DID_ERROR:
1732                 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1733                     status_byte(scmd->result) == RESERVATION_CONFLICT)
1734                         return 0;
1735                 /* fall through */
1736         case DID_SOFT_ERROR:
1737                 return (scmd->request->cmd_flags & REQ_FAILFAST_DRIVER);
1738         }
1739
1740         if (status_byte(scmd->result) != CHECK_CONDITION)
1741                 return 0;
1742
1743 check_type:
1744         /*
1745          * assume caller has checked sense and determined
1746          * the check condition was retryable.
1747          */
1748         if (scmd->request->cmd_flags & REQ_FAILFAST_DEV ||
1749             scmd->request->cmd_type == REQ_TYPE_BLOCK_PC)
1750                 return 1;
1751         else
1752                 return 0;
1753 }
1754
1755 /**
1756  * scsi_decide_disposition - Disposition a cmd on return from LLD.
1757  * @scmd:       SCSI cmd to examine.
1758  *
1759  * Notes:
1760  *    This is *only* called when we are examining the status after sending
1761  *    out the actual data command.  any commands that are queued for error
1762  *    recovery (e.g. test_unit_ready) do *not* come through here.
1763  *
1764  *    When this routine returns failed, it means the error handler thread
1765  *    is woken.  In cases where the error code indicates an error that
1766  *    doesn't require the error handler read (i.e. we don't need to
1767  *    abort/reset), this function should return SUCCESS.
1768  */
1769 int scsi_decide_disposition(struct scsi_cmnd *scmd)
1770 {
1771         int rtn;
1772
1773         /*
1774          * if the device is offline, then we clearly just pass the result back
1775          * up to the top level.
1776          */
1777         if (!scsi_device_online(scmd->device)) {
1778                 SCSI_LOG_ERROR_RECOVERY(5, scmd_printk(KERN_INFO, scmd,
1779                         "%s: device offline - report as SUCCESS\n", __func__));
1780                 return SUCCESS;
1781         }
1782
1783         /*
1784          * first check the host byte, to see if there is anything in there
1785          * that would indicate what we need to do.
1786          */
1787         switch (host_byte(scmd->result)) {
1788         case DID_PASSTHROUGH:
1789                 /*
1790                  * no matter what, pass this through to the upper layer.
1791                  * nuke this special code so that it looks like we are saying
1792                  * did_ok.
1793                  */
1794                 scmd->result &= 0xff00ffff;
1795                 return SUCCESS;
1796         case DID_OK:
1797                 /*
1798                  * looks good.  drop through, and check the next byte.
1799                  */
1800                 break;
1801         case DID_ABORT:
1802                 if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) {
1803                         set_host_byte(scmd, DID_TIME_OUT);
1804                         return SUCCESS;
1805                 }
1806         case DID_NO_CONNECT:
1807         case DID_BAD_TARGET:
1808                 /*
1809                  * note - this means that we just report the status back
1810                  * to the top level driver, not that we actually think
1811                  * that it indicates SUCCESS.
1812                  */
1813                 return SUCCESS;
1814                 /*
1815                  * when the low level driver returns did_soft_error,
1816                  * it is responsible for keeping an internal retry counter
1817                  * in order to avoid endless loops (db)
1818                  *
1819                  * actually this is a bug in this function here.  we should
1820                  * be mindful of the maximum number of retries specified
1821                  * and not get stuck in a loop.
1822                  */
1823         case DID_SOFT_ERROR:
1824                 goto maybe_retry;
1825         case DID_IMM_RETRY:
1826                 return NEEDS_RETRY;
1827
1828         case DID_REQUEUE:
1829                 return ADD_TO_MLQUEUE;
1830         case DID_TRANSPORT_DISRUPTED:
1831                 /*
1832                  * LLD/transport was disrupted during processing of the IO.
1833                  * The transport class is now blocked/blocking,
1834                  * and the transport will decide what to do with the IO
1835                  * based on its timers and recovery capablilities if
1836                  * there are enough retries.
1837                  */
1838                 goto maybe_retry;
1839         case DID_TRANSPORT_FAILFAST:
1840                 /*
1841                  * The transport decided to failfast the IO (most likely
1842                  * the fast io fail tmo fired), so send IO directly upwards.
1843                  */
1844                 return SUCCESS;
1845         case DID_ERROR:
1846                 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1847                     status_byte(scmd->result) == RESERVATION_CONFLICT)
1848                         /*
1849                          * execute reservation conflict processing code
1850                          * lower down
1851                          */
1852                         break;
1853                 /* fallthrough */
1854         case DID_BUS_BUSY:
1855         case DID_PARITY:
1856                 goto maybe_retry;
1857         case DID_TIME_OUT:
1858                 /*
1859                  * when we scan the bus, we get timeout messages for
1860                  * these commands if there is no device available.
1861                  * other hosts report did_no_connect for the same thing.
1862                  */
1863                 if ((scmd->cmnd[0] == TEST_UNIT_READY ||
1864                      scmd->cmnd[0] == INQUIRY)) {
1865                         return SUCCESS;
1866                 } else {
1867                         return FAILED;
1868                 }
1869         case DID_RESET:
1870                 return SUCCESS;
1871         default:
1872                 return FAILED;
1873         }
1874
1875         /*
1876          * next, check the message byte.
1877          */
1878         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
1879                 return FAILED;
1880
1881         /*
1882          * check the status byte to see if this indicates anything special.
1883          */
1884         switch (status_byte(scmd->result)) {
1885         case QUEUE_FULL:
1886                 scsi_handle_queue_full(scmd->device);
1887                 /*
1888                  * the case of trying to send too many commands to a
1889                  * tagged queueing device.
1890                  */
1891         case BUSY:
1892                 /*
1893                  * device can't talk to us at the moment.  Should only
1894                  * occur (SAM-3) when the task queue is empty, so will cause
1895                  * the empty queue handling to trigger a stall in the
1896                  * device.
1897                  */
1898                 return ADD_TO_MLQUEUE;
1899         case GOOD:
1900                 if (scmd->cmnd[0] == REPORT_LUNS)
1901                         scmd->device->sdev_target->expecting_lun_change = 0;
1902                 scsi_handle_queue_ramp_up(scmd->device);
1903         case COMMAND_TERMINATED:
1904                 return SUCCESS;
1905         case TASK_ABORTED:
1906                 goto maybe_retry;
1907         case CHECK_CONDITION:
1908                 rtn = scsi_check_sense(scmd);
1909                 if (rtn == NEEDS_RETRY)
1910                         goto maybe_retry;
1911                 /* if rtn == FAILED, we have no sense information;
1912                  * returning FAILED will wake the error handler thread
1913                  * to collect the sense and redo the decide
1914                  * disposition */
1915                 return rtn;
1916         case CONDITION_GOOD:
1917         case INTERMEDIATE_GOOD:
1918         case INTERMEDIATE_C_GOOD:
1919         case ACA_ACTIVE:
1920                 /*
1921                  * who knows?  FIXME(eric)
1922                  */
1923                 return SUCCESS;
1924
1925         case RESERVATION_CONFLICT:
1926                 sdev_printk(KERN_INFO, scmd->device,
1927                             "reservation conflict\n");
1928                 set_host_byte(scmd, DID_NEXUS_FAILURE);
1929                 return SUCCESS; /* causes immediate i/o error */
1930         default:
1931                 return FAILED;
1932         }
1933         return FAILED;
1934
1935       maybe_retry:
1936
1937         /* we requeue for retry because the error was retryable, and
1938          * the request was not marked fast fail.  Note that above,
1939          * even if the request is marked fast fail, we still requeue
1940          * for queue congestion conditions (QUEUE_FULL or BUSY) */
1941         if ((++scmd->retries) <= scmd->allowed
1942             && !scsi_noretry_cmd(scmd)) {
1943                 return NEEDS_RETRY;
1944         } else {
1945                 /*
1946                  * no more retries - report this one back to upper level.
1947                  */
1948                 return SUCCESS;
1949         }
1950 }
1951
1952 static void eh_lock_door_done(struct request *req, int uptodate)
1953 {
1954         __blk_put_request(req->q, req);
1955 }
1956
1957 /**
1958  * scsi_eh_lock_door - Prevent medium removal for the specified device
1959  * @sdev:       SCSI device to prevent medium removal
1960  *
1961  * Locking:
1962  *      We must be called from process context.
1963  *
1964  * Notes:
1965  *      We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
1966  *      head of the devices request queue, and continue.
1967  */
1968 static void scsi_eh_lock_door(struct scsi_device *sdev)
1969 {
1970         struct request *req;
1971
1972         /*
1973          * blk_get_request with GFP_KERNEL (__GFP_RECLAIM) sleeps until a
1974          * request becomes available
1975          */
1976         req = blk_get_request(sdev->request_queue, READ, GFP_KERNEL);
1977         if (IS_ERR(req))
1978                 return;
1979
1980         blk_rq_set_block_pc(req);
1981
1982         req->cmd[0] = ALLOW_MEDIUM_REMOVAL;
1983         req->cmd[1] = 0;
1984         req->cmd[2] = 0;
1985         req->cmd[3] = 0;
1986         req->cmd[4] = SCSI_REMOVAL_PREVENT;
1987         req->cmd[5] = 0;
1988
1989         req->cmd_len = COMMAND_SIZE(req->cmd[0]);
1990
1991         req->cmd_flags |= REQ_QUIET;
1992         req->timeout = 10 * HZ;
1993         req->retries = 5;
1994
1995         blk_execute_rq_nowait(req->q, NULL, req, 1, eh_lock_door_done);
1996 }
1997
1998 /**
1999  * scsi_restart_operations - restart io operations to the specified host.
2000  * @shost:      Host we are restarting.
2001  *
2002  * Notes:
2003  *    When we entered the error handler, we blocked all further i/o to
2004  *    this device.  we need to 'reverse' this process.
2005  */
2006 static void scsi_restart_operations(struct Scsi_Host *shost)
2007 {
2008         struct scsi_device *sdev;
2009         unsigned long flags;
2010
2011         /*
2012          * If the door was locked, we need to insert a door lock request
2013          * onto the head of the SCSI request queue for the device.  There
2014          * is no point trying to lock the door of an off-line device.
2015          */
2016         shost_for_each_device(sdev, shost) {
2017                 if (scsi_device_online(sdev) && sdev->was_reset && sdev->locked) {
2018                         scsi_eh_lock_door(sdev);
2019                         sdev->was_reset = 0;
2020                 }
2021         }
2022
2023         /*
2024          * next free up anything directly waiting upon the host.  this
2025          * will be requests for character device operations, and also for
2026          * ioctls to queued block devices.
2027          */
2028         SCSI_LOG_ERROR_RECOVERY(3,
2029                 shost_printk(KERN_INFO, shost, "waking up host to restart\n"));
2030
2031         spin_lock_irqsave(shost->host_lock, flags);
2032         if (scsi_host_set_state(shost, SHOST_RUNNING))
2033                 if (scsi_host_set_state(shost, SHOST_CANCEL))
2034                         BUG_ON(scsi_host_set_state(shost, SHOST_DEL));
2035         spin_unlock_irqrestore(shost->host_lock, flags);
2036
2037         wake_up(&shost->host_wait);
2038
2039         /*
2040          * finally we need to re-initiate requests that may be pending.  we will
2041          * have had everything blocked while error handling is taking place, and
2042          * now that error recovery is done, we will need to ensure that these
2043          * requests are started.
2044          */
2045         scsi_run_host_queues(shost);
2046
2047         /*
2048          * if eh is active and host_eh_scheduled is pending we need to re-run
2049          * recovery.  we do this check after scsi_run_host_queues() to allow
2050          * everything pent up since the last eh run a chance to make forward
2051          * progress before we sync again.  Either we'll immediately re-run
2052          * recovery or scsi_device_unbusy() will wake us again when these
2053          * pending commands complete.
2054          */
2055         spin_lock_irqsave(shost->host_lock, flags);
2056         if (shost->host_eh_scheduled)
2057                 if (scsi_host_set_state(shost, SHOST_RECOVERY))
2058                         WARN_ON(scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY));
2059         spin_unlock_irqrestore(shost->host_lock, flags);
2060 }
2061
2062 /**
2063  * scsi_eh_ready_devs - check device ready state and recover if not.
2064  * @shost:      host to be recovered.
2065  * @work_q:     &list_head for pending commands.
2066  * @done_q:     &list_head for processed commands.
2067  */
2068 void scsi_eh_ready_devs(struct Scsi_Host *shost,
2069                         struct list_head *work_q,
2070                         struct list_head *done_q)
2071 {
2072         if (!scsi_eh_stu(shost, work_q, done_q))
2073                 if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
2074                         if (!scsi_eh_target_reset(shost, work_q, done_q))
2075                                 if (!scsi_eh_bus_reset(shost, work_q, done_q))
2076                                         if (!scsi_eh_host_reset(shost, work_q, done_q))
2077                                                 scsi_eh_offline_sdevs(work_q,
2078                                                                       done_q);
2079 }
2080 EXPORT_SYMBOL_GPL(scsi_eh_ready_devs);
2081
2082 /**
2083  * scsi_eh_flush_done_q - finish processed commands or retry them.
2084  * @done_q:     list_head of processed commands.
2085  */
2086 void scsi_eh_flush_done_q(struct list_head *done_q)
2087 {
2088         struct scsi_cmnd *scmd, *next;
2089
2090         list_for_each_entry_safe(scmd, next, done_q, eh_entry) {
2091                 list_del_init(&scmd->eh_entry);
2092                 if (scsi_device_online(scmd->device) &&
2093                     !scsi_noretry_cmd(scmd) &&
2094                     (++scmd->retries <= scmd->allowed)) {
2095                         SCSI_LOG_ERROR_RECOVERY(3,
2096                                 scmd_printk(KERN_INFO, scmd,
2097                                              "%s: flush retry cmd\n",
2098                                              current->comm));
2099                                 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
2100                 } else {
2101                         /*
2102                          * If just we got sense for the device (called
2103                          * scsi_eh_get_sense), scmd->result is already
2104                          * set, do not set DRIVER_TIMEOUT.
2105                          */
2106                         if (!scmd->result)
2107                                 scmd->result |= (DRIVER_TIMEOUT << 24);
2108                         SCSI_LOG_ERROR_RECOVERY(3,
2109                                 scmd_printk(KERN_INFO, scmd,
2110                                              "%s: flush finish cmd\n",
2111                                              current->comm));
2112                         scsi_finish_command(scmd);
2113                 }
2114         }
2115 }
2116 EXPORT_SYMBOL(scsi_eh_flush_done_q);
2117
2118 /**
2119  * scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
2120  * @shost:      Host to unjam.
2121  *
2122  * Notes:
2123  *    When we come in here, we *know* that all commands on the bus have
2124  *    either completed, failed or timed out.  we also know that no further
2125  *    commands are being sent to the host, so things are relatively quiet
2126  *    and we have freedom to fiddle with things as we wish.
2127  *
2128  *    This is only the *default* implementation.  it is possible for
2129  *    individual drivers to supply their own version of this function, and
2130  *    if the maintainer wishes to do this, it is strongly suggested that
2131  *    this function be taken as a template and modified.  this function
2132  *    was designed to correctly handle problems for about 95% of the
2133  *    different cases out there, and it should always provide at least a
2134  *    reasonable amount of error recovery.
2135  *
2136  *    Any command marked 'failed' or 'timeout' must eventually have
2137  *    scsi_finish_cmd() called for it.  we do all of the retry stuff
2138  *    here, so when we restart the host after we return it should have an
2139  *    empty queue.
2140  */
2141 static void scsi_unjam_host(struct Scsi_Host *shost)
2142 {
2143         unsigned long flags;
2144         LIST_HEAD(eh_work_q);
2145         LIST_HEAD(eh_done_q);
2146
2147         spin_lock_irqsave(shost->host_lock, flags);
2148         list_splice_init(&shost->eh_cmd_q, &eh_work_q);
2149         spin_unlock_irqrestore(shost->host_lock, flags);
2150
2151         SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
2152
2153         if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
2154                 if (!scsi_eh_abort_cmds(&eh_work_q, &eh_done_q))
2155                         scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
2156
2157         spin_lock_irqsave(shost->host_lock, flags);
2158         if (shost->eh_deadline != -1)
2159                 shost->last_reset = 0;
2160         spin_unlock_irqrestore(shost->host_lock, flags);
2161         scsi_eh_flush_done_q(&eh_done_q);
2162 }
2163
2164 /**
2165  * scsi_error_handler - SCSI error handler thread
2166  * @data:       Host for which we are running.
2167  *
2168  * Notes:
2169  *    This is the main error handling loop.  This is run as a kernel thread
2170  *    for every SCSI host and handles all error handling activity.
2171  */
2172 int scsi_error_handler(void *data)
2173 {
2174         struct Scsi_Host *shost = data;
2175
2176         /*
2177          * We use TASK_INTERRUPTIBLE so that the thread is not
2178          * counted against the load average as a running process.
2179          * We never actually get interrupted because kthread_run
2180          * disables signal delivery for the created thread.
2181          */
2182         while (true) {
2183                 /*
2184                  * The sequence in kthread_stop() sets the stop flag first
2185                  * then wakes the process.  To avoid missed wakeups, the task
2186                  * should always be in a non running state before the stop
2187                  * flag is checked
2188                  */
2189                 set_current_state(TASK_INTERRUPTIBLE);
2190                 if (kthread_should_stop())
2191                         break;
2192
2193                 if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||
2194                     shost->host_failed != atomic_read(&shost->host_busy)) {
2195                         SCSI_LOG_ERROR_RECOVERY(1,
2196                                 shost_printk(KERN_INFO, shost,
2197                                              "scsi_eh_%d: sleeping\n",
2198                                              shost->host_no));
2199                         schedule();
2200                         continue;
2201                 }
2202
2203                 __set_current_state(TASK_RUNNING);
2204                 SCSI_LOG_ERROR_RECOVERY(1,
2205                         shost_printk(KERN_INFO, shost,
2206                                      "scsi_eh_%d: waking up %d/%d/%d\n",
2207                                      shost->host_no, shost->host_eh_scheduled,
2208                                      shost->host_failed,
2209                                      atomic_read(&shost->host_busy)));
2210
2211                 /*
2212                  * We have a host that is failing for some reason.  Figure out
2213                  * what we need to do to get it up and online again (if we can).
2214                  * If we fail, we end up taking the thing offline.
2215                  */
2216                 if (!shost->eh_noresume && scsi_autopm_get_host(shost) != 0) {
2217                         SCSI_LOG_ERROR_RECOVERY(1,
2218                                 shost_printk(KERN_ERR, shost,
2219                                              "scsi_eh_%d: unable to autoresume\n",
2220                                              shost->host_no));
2221                         continue;
2222                 }
2223
2224                 if (shost->transportt->eh_strategy_handler)
2225                         shost->transportt->eh_strategy_handler(shost);
2226                 else
2227                         scsi_unjam_host(shost);
2228
2229                 /* All scmds have been handled */
2230                 shost->host_failed = 0;
2231
2232                 /*
2233                  * Note - if the above fails completely, the action is to take
2234                  * individual devices offline and flush the queue of any
2235                  * outstanding requests that may have been pending.  When we
2236                  * restart, we restart any I/O to any other devices on the bus
2237                  * which are still online.
2238                  */
2239                 scsi_restart_operations(shost);
2240                 if (!shost->eh_noresume)
2241                         scsi_autopm_put_host(shost);
2242         }
2243         __set_current_state(TASK_RUNNING);
2244
2245         SCSI_LOG_ERROR_RECOVERY(1,
2246                 shost_printk(KERN_INFO, shost,
2247                              "Error handler scsi_eh_%d exiting\n",
2248                              shost->host_no));
2249         shost->ehandler = NULL;
2250         return 0;
2251 }
2252
2253 /*
2254  * Function:    scsi_report_bus_reset()
2255  *
2256  * Purpose:     Utility function used by low-level drivers to report that
2257  *              they have observed a bus reset on the bus being handled.
2258  *
2259  * Arguments:   shost       - Host in question
2260  *              channel     - channel on which reset was observed.
2261  *
2262  * Returns:     Nothing
2263  *
2264  * Lock status: Host lock must be held.
2265  *
2266  * Notes:       This only needs to be called if the reset is one which
2267  *              originates from an unknown location.  Resets originated
2268  *              by the mid-level itself don't need to call this, but there
2269  *              should be no harm.
2270  *
2271  *              The main purpose of this is to make sure that a CHECK_CONDITION
2272  *              is properly treated.
2273  */
2274 void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
2275 {
2276         struct scsi_device *sdev;
2277
2278         __shost_for_each_device(sdev, shost) {
2279                 if (channel == sdev_channel(sdev))
2280                         __scsi_report_device_reset(sdev, NULL);
2281         }
2282 }
2283 EXPORT_SYMBOL(scsi_report_bus_reset);
2284
2285 /*
2286  * Function:    scsi_report_device_reset()
2287  *
2288  * Purpose:     Utility function used by low-level drivers to report that
2289  *              they have observed a device reset on the device being handled.
2290  *
2291  * Arguments:   shost       - Host in question
2292  *              channel     - channel on which reset was observed
2293  *              target      - target on which reset was observed
2294  *
2295  * Returns:     Nothing
2296  *
2297  * Lock status: Host lock must be held
2298  *
2299  * Notes:       This only needs to be called if the reset is one which
2300  *              originates from an unknown location.  Resets originated
2301  *              by the mid-level itself don't need to call this, but there
2302  *              should be no harm.
2303  *
2304  *              The main purpose of this is to make sure that a CHECK_CONDITION
2305  *              is properly treated.
2306  */
2307 void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
2308 {
2309         struct scsi_device *sdev;
2310
2311         __shost_for_each_device(sdev, shost) {
2312                 if (channel == sdev_channel(sdev) &&
2313                     target == sdev_id(sdev))
2314                         __scsi_report_device_reset(sdev, NULL);
2315         }
2316 }
2317 EXPORT_SYMBOL(scsi_report_device_reset);
2318
2319 static void
2320 scsi_reset_provider_done_command(struct scsi_cmnd *scmd)
2321 {
2322 }
2323
2324 /**
2325  * scsi_ioctl_reset: explicitly reset a host/bus/target/device
2326  * @dev:        scsi_device to operate on
2327  * @arg:        reset type (see sg.h)
2328  */
2329 int
2330 scsi_ioctl_reset(struct scsi_device *dev, int __user *arg)
2331 {
2332         struct scsi_cmnd *scmd;
2333         struct Scsi_Host *shost = dev->host;
2334         struct request req;
2335         unsigned long flags;
2336         int error = 0, rtn, val;
2337
2338         if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2339                 return -EACCES;
2340
2341         error = get_user(val, arg);
2342         if (error)
2343                 return error;
2344
2345         if (scsi_autopm_get_host(shost) < 0)
2346                 return -EIO;
2347
2348         error = -EIO;
2349         scmd = scsi_get_command(dev, GFP_KERNEL);
2350         if (!scmd)
2351                 goto out_put_autopm_host;
2352
2353         blk_rq_init(NULL, &req);
2354         scmd->request = &req;
2355
2356         scmd->cmnd = req.cmd;
2357
2358         scmd->scsi_done         = scsi_reset_provider_done_command;
2359         memset(&scmd->sdb, 0, sizeof(scmd->sdb));
2360
2361         scmd->cmd_len                   = 0;
2362
2363         scmd->sc_data_direction         = DMA_BIDIRECTIONAL;
2364
2365         spin_lock_irqsave(shost->host_lock, flags);
2366         shost->tmf_in_progress = 1;
2367         spin_unlock_irqrestore(shost->host_lock, flags);
2368
2369         switch (val & ~SG_SCSI_RESET_NO_ESCALATE) {
2370         case SG_SCSI_RESET_NOTHING:
2371                 rtn = SUCCESS;
2372                 break;
2373         case SG_SCSI_RESET_DEVICE:
2374                 rtn = scsi_try_bus_device_reset(scmd);
2375                 if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
2376                         break;
2377                 /* FALLTHROUGH */
2378         case SG_SCSI_RESET_TARGET:
2379                 rtn = scsi_try_target_reset(scmd);
2380                 if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
2381                         break;
2382                 /* FALLTHROUGH */
2383         case SG_SCSI_RESET_BUS:
2384                 rtn = scsi_try_bus_reset(scmd);
2385                 if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
2386                         break;
2387                 /* FALLTHROUGH */
2388         case SG_SCSI_RESET_HOST:
2389                 rtn = scsi_try_host_reset(scmd);
2390                 if (rtn == SUCCESS)
2391                         break;
2392         default:
2393                 /* FALLTHROUGH */
2394                 rtn = FAILED;
2395                 break;
2396         }
2397
2398         error = (rtn == SUCCESS) ? 0 : -EIO;
2399
2400         spin_lock_irqsave(shost->host_lock, flags);
2401         shost->tmf_in_progress = 0;
2402         spin_unlock_irqrestore(shost->host_lock, flags);
2403
2404         /*
2405          * be sure to wake up anyone who was sleeping or had their queue
2406          * suspended while we performed the TMF.
2407          */
2408         SCSI_LOG_ERROR_RECOVERY(3,
2409                 shost_printk(KERN_INFO, shost,
2410                              "waking up host to restart after TMF\n"));
2411
2412         wake_up(&shost->host_wait);
2413         scsi_run_host_queues(shost);
2414
2415         scsi_put_command(scmd);
2416
2417 out_put_autopm_host:
2418         scsi_autopm_put_host(shost);
2419         return error;
2420 }
2421 EXPORT_SYMBOL(scsi_ioctl_reset);
2422
2423 bool scsi_command_normalize_sense(const struct scsi_cmnd *cmd,
2424                                   struct scsi_sense_hdr *sshdr)
2425 {
2426         return scsi_normalize_sense(cmd->sense_buffer,
2427                         SCSI_SENSE_BUFFERSIZE, sshdr);
2428 }
2429 EXPORT_SYMBOL(scsi_command_normalize_sense);
2430
2431 /**
2432  * scsi_get_sense_info_fld - get information field from sense data (either fixed or descriptor format)
2433  * @sense_buffer:       byte array of sense data
2434  * @sb_len:             number of valid bytes in sense_buffer
2435  * @info_out:           pointer to 64 integer where 8 or 4 byte information
2436  *                      field will be placed if found.
2437  *
2438  * Return value:
2439  *      1 if information field found, 0 if not found.
2440  */
2441 int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
2442                             u64 * info_out)
2443 {
2444         int j;
2445         const u8 * ucp;
2446         u64 ull;
2447
2448         if (sb_len < 7)
2449                 return 0;
2450         switch (sense_buffer[0] & 0x7f) {
2451         case 0x70:
2452         case 0x71:
2453                 if (sense_buffer[0] & 0x80) {
2454                         *info_out = (sense_buffer[3] << 24) +
2455                                     (sense_buffer[4] << 16) +
2456                                     (sense_buffer[5] << 8) + sense_buffer[6];
2457                         return 1;
2458                 } else
2459                         return 0;
2460         case 0x72:
2461         case 0x73:
2462                 ucp = scsi_sense_desc_find(sense_buffer, sb_len,
2463                                            0 /* info desc */);
2464                 if (ucp && (0xa == ucp[1])) {
2465                         ull = 0;
2466                         for (j = 0; j < 8; ++j) {
2467                                 if (j > 0)
2468                                         ull <<= 8;
2469                                 ull |= ucp[4 + j];
2470                         }
2471                         *info_out = ull;
2472                         return 1;
2473                 } else
2474                         return 0;
2475         default:
2476                 return 0;
2477         }
2478 }
2479 EXPORT_SYMBOL(scsi_get_sense_info_fld);