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_transport.h>
  37 #include <scsi/scsi_host.h>
  38 #include <scsi/scsi_ioctl.h>
  39
  40 #include "scsi_priv.h"
  41 #include "scsi_logging.h"
  42 #include "scsi_transport_api.h"
  43
  44 #include <trace/events/scsi.h>
  45
  46 static void scsi_eh_done(struct scsi_cmnd *scmd);
  47
  48 /*
  49  * These should *probably* be handled by the host itself.
  50  * Since it is allowed to sleep, it probably should.
  51  */
  52 #define BUS_RESET_SETTLE_TIME   (10)
  53 #define HOST_RESET_SETTLE_TIME  (10)
  54
  55 static int scsi_eh_try_stu(struct scsi_cmnd *scmd);
  56 static int scsi_try_to_abort_cmd(struct scsi_host_template *,
  57                                  struct scsi_cmnd *);
  58
  59 /* called with shost->host_lock held */
  60 void scsi_eh_wakeup(struct Scsi_Host *shost)
  61 {
  62         if (atomic_read(&shost->host_busy) == shost->host_failed) {
  63                 trace_scsi_eh_wakeup(shost);
  64                 wake_up_process(shost->ehandler);
  65                 SCSI_LOG_ERROR_RECOVERY(5, shost_printk(KERN_INFO, shost,
  66                         "Waking error handler thread\n"));
  67         }
  68 }
  69
  70 /**
  71  * scsi_schedule_eh - schedule EH for SCSI host
  72  * @shost:      SCSI host to invoke error handling on.
  73  *
  74  * Schedule SCSI EH without scmd.
  75  */
  76 void scsi_schedule_eh(struct Scsi_Host *shost)
  77 {
  78         unsigned long flags;
  79
  80         spin_lock_irqsave(shost->host_lock, flags);
  81
  82         if (scsi_host_set_state(shost, SHOST_RECOVERY) == 0 ||
  83             scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY) == 0) {
  84                 shost->host_eh_scheduled++;
  85                 scsi_eh_wakeup(shost);
  86         }
  87
  88         spin_unlock_irqrestore(shost->host_lock, flags);
  89 }
  90 EXPORT_SYMBOL_GPL(scsi_schedule_eh);
  91
  92 static int scsi_host_eh_past_deadline(struct Scsi_Host *shost)
  93 {
  94         if (!shost->last_reset || shost->eh_deadline == -1)
  95                 return 0;
  96
  97         /*
  98          * 32bit accesses are guaranteed to be atomic
  99          * (on all supported architectures), so instead
 100          * of using a spinlock we can as well double check
 101          * if eh_deadline has been set to 'off' during the
 102          * time_before call.
 103          */
 104         if (time_before(jiffies, shost->last_reset + shost->eh_deadline) &&
 105             shost->eh_deadline > -1)
 106                 return 0;
 107
 108         return 1;
 109 }
 110
 111 /**
 112  * scmd_eh_abort_handler - Handle command aborts
 113  * @work:       command to be aborted.
 114  */
 115 void
 116 scmd_eh_abort_handler(struct work_struct *work)
 117 {
 118         struct scsi_cmnd *scmd =
 119                 container_of(work, struct scsi_cmnd, abort_work.work);
 120         struct scsi_device *sdev = scmd->device;
 121         int rtn;
 122
 123         if (scsi_host_eh_past_deadline(sdev->host)) {
 124                 SCSI_LOG_ERROR_RECOVERY(3,
 125                         scmd_printk(KERN_INFO, scmd,
 126                                     "scmd %p eh timeout, not aborting\n",
 127                                     scmd));
 128         } else {
 129                 SCSI_LOG_ERROR_RECOVERY(3,
 130                         scmd_printk(KERN_INFO, scmd,
 131                                     "aborting command %p\n", scmd));
 132                 rtn = scsi_try_to_abort_cmd(sdev->host->hostt, scmd);
 133                 if (rtn == SUCCESS) {
 134                         set_host_byte(scmd, DID_TIME_OUT);
 135                         if (scsi_host_eh_past_deadline(sdev->host)) {
 136                                 SCSI_LOG_ERROR_RECOVERY(3,
 137                                         scmd_printk(KERN_INFO, scmd,
 138                                                     "scmd %p eh timeout, "
 139                                                     "not retrying aborted "
 140                                                     "command\n", scmd));
 141                         } else if (!scsi_noretry_cmd(scmd) &&
 142                             (++scmd->retries <= scmd->allowed)) {
 143                                 SCSI_LOG_ERROR_RECOVERY(3,
 144                                         scmd_printk(KERN_WARNING, scmd,
 145                                                     "scmd %p retry "
 146                                                     "aborted command\n", scmd));
 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                                                     "scmd %p finish "
 153                                                     "aborted command\n", scmd));
 154                                 scsi_finish_command(scmd);
 155                                 return;
 156                         }
 157                 } else {
 158                         SCSI_LOG_ERROR_RECOVERY(3,
 159                                 scmd_printk(KERN_INFO, scmd,
 160                                             "scmd %p abort failed, rtn %d\n",
 161                                             scmd, rtn));
 162                 }
 163         }
 164
 165         if (!scsi_eh_scmd_add(scmd, 0)) {
 166                 SCSI_LOG_ERROR_RECOVERY(3,
 167                         scmd_printk(KERN_WARNING, scmd,
 168                                     "scmd %p terminate "
 169                                     "aborted command\n", scmd));
 170                 set_host_byte(scmd, DID_TIME_OUT);
 171                 scsi_finish_command(scmd);
 172         }
 173 }
 174
 175 /**
 176  * scsi_abort_command - schedule a command abort
 177  * @scmd:       scmd to abort.
 178  *
 179  * We only need to abort commands after a command timeout
 180  */
 181 static int
 182 scsi_abort_command(struct scsi_cmnd *scmd)
 183 {
 184         struct scsi_device *sdev = scmd->device;
 185         struct Scsi_Host *shost = sdev->host;
 186         unsigned long flags;
 187
 188         if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) {
 189                 /*
 190                  * Retry after abort failed, escalate to next level.
 191                  */
 192                 scmd->eh_eflags &= ~SCSI_EH_ABORT_SCHEDULED;
 193                 SCSI_LOG_ERROR_RECOVERY(3,
 194                         scmd_printk(KERN_INFO, scmd,
 195                                     "scmd %p previous abort failed\n", scmd));
 196                 BUG_ON(delayed_work_pending(&scmd->abort_work));
 197                 return FAILED;
 198         }
 199
 200         /*
 201          * Do not try a command abort if
 202          * SCSI EH has already started.
 203          */
 204         spin_lock_irqsave(shost->host_lock, flags);
 205         if (scsi_host_in_recovery(shost)) {
 206                 spin_unlock_irqrestore(shost->host_lock, flags);
 207                 SCSI_LOG_ERROR_RECOVERY(3,
 208                         scmd_printk(KERN_INFO, scmd,
 209                                     "scmd %p not aborting, host in recovery\n",
 210                                     scmd));
 211                 return FAILED;
 212         }
 213
 214         if (shost->eh_deadline != -1 && !shost->last_reset)
 215                 shost->last_reset = jiffies;
 216         spin_unlock_irqrestore(shost->host_lock, flags);
 217
 218         scmd->eh_eflags |= SCSI_EH_ABORT_SCHEDULED;
 219         SCSI_LOG_ERROR_RECOVERY(3,
 220                 scmd_printk(KERN_INFO, scmd,
 221                             "scmd %p abort scheduled\n", scmd));
 222         queue_delayed_work(shost->tmf_work_q, &scmd->abort_work, HZ / 100);
 223         return SUCCESS;
 224 }
 225
 226 /**
 227  * scsi_eh_scmd_add - add scsi cmd to error handling.
 228  * @scmd:       scmd to run eh on.
 229  * @eh_flag:    optional SCSI_EH flag.
 230  *
 231  * Return value:
 232  *      0 on failure.
 233  */
 234 int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
 235 {
 236         struct Scsi_Host *shost = scmd->device->host;
 237         unsigned long flags;
 238         int ret = 0;
 239
 240         if (!shost->ehandler)
 241                 return 0;
 242
 243         spin_lock_irqsave(shost->host_lock, flags);
 244         if (scsi_host_set_state(shost, SHOST_RECOVERY))
 245                 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY))
 246                         goto out_unlock;
 247
 248         if (shost->eh_deadline != -1 && !shost->last_reset)
 249                 shost->last_reset = jiffies;
 250
 251         ret = 1;
 252         if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED)
 253                 eh_flag &= ~SCSI_EH_CANCEL_CMD;
 254         scmd->eh_eflags |= eh_flag;
 255         list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
 256         shost->host_failed++;
 257         scsi_eh_wakeup(shost);
 258  out_unlock:
 259         spin_unlock_irqrestore(shost->host_lock, flags);
 260         return ret;
 261 }
 262
 263 /**
 264  * scsi_times_out - Timeout function for normal scsi commands.
 265  * @req:        request that is timing out.
 266  *
 267  * Notes:
 268  *     We do not need to lock this.  There is the potential for a race
 269  *     only in that the normal completion handling might run, but if the
 270  *     normal completion function determines that the timer has already
 271  *     fired, then it mustn't do anything.
 272  */
 273 enum blk_eh_timer_return scsi_times_out(struct request *req)
 274 {
 275         struct scsi_cmnd *scmd = req->special;
 276         enum blk_eh_timer_return rtn = BLK_EH_NOT_HANDLED;
 277         struct Scsi_Host *host = scmd->device->host;
 278
 279         trace_scsi_dispatch_cmd_timeout(scmd);
 280         scsi_log_completion(scmd, TIMEOUT_ERROR);
 281
 282         if (host->eh_deadline != -1 && !host->last_reset)
 283                 host->last_reset = jiffies;
 284
 285         if (host->transportt->eh_timed_out)
 286                 rtn = host->transportt->eh_timed_out(scmd);
 287         else if (host->hostt->eh_timed_out)
 288                 rtn = host->hostt->eh_timed_out(scmd);
 289
 290         if (rtn == BLK_EH_NOT_HANDLED) {
 291                 if (!host->hostt->no_async_abort &&
 292                     scsi_abort_command(scmd) == SUCCESS)
 293                         return BLK_EH_NOT_HANDLED;
 294
 295                 set_host_byte(scmd, DID_TIME_OUT);
 296                 if (!scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD))
 297                         rtn = BLK_EH_HANDLED;
 298         }
 299
 300         return rtn;
 301 }
 302
 303 /**
 304  * scsi_block_when_processing_errors - Prevent cmds from being queued.
 305  * @sdev:       Device on which we are performing recovery.
 306  *
 307  * Description:
 308  *     We block until the host is out of error recovery, and then check to
 309  *     see whether the host or the device is offline.
 310  *
 311  * Return value:
 312  *     0 when dev was taken offline by error recovery. 1 OK to proceed.
 313  */
 314 int scsi_block_when_processing_errors(struct scsi_device *sdev)
 315 {
 316         int online;
 317
 318         wait_event(sdev->host->host_wait, !scsi_host_in_recovery(sdev->host));
 319
 320         online = scsi_device_online(sdev);
 321
 322         SCSI_LOG_ERROR_RECOVERY(5, sdev_printk(KERN_INFO, sdev,
 323                 "%s: rtn: %d\n", __func__, online));
 324
 325         return online;
 326 }
 327 EXPORT_SYMBOL(scsi_block_when_processing_errors);
 328
 329 #ifdef CONFIG_SCSI_LOGGING
 330 /**
 331  * scsi_eh_prt_fail_stats - Log info on failures.
 332  * @shost:      scsi host being recovered.
 333  * @work_q:     Queue of scsi cmds to process.
 334  */
 335 static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
 336                                           struct list_head *work_q)
 337 {
 338         struct scsi_cmnd *scmd;
 339         struct scsi_device *sdev;
 340         int total_failures = 0;
 341         int cmd_failed = 0;
 342         int cmd_cancel = 0;
 343         int devices_failed = 0;
 344
 345         shost_for_each_device(sdev, shost) {
 346                 list_for_each_entry(scmd, work_q, eh_entry) {
 347                         if (scmd->device == sdev) {
 348                                 ++total_failures;
 349                                 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD)
 350                                         ++cmd_cancel;
 351                                 else
 352                                         ++cmd_failed;
 353                         }
 354                 }
 355
 356                 if (cmd_cancel || cmd_failed) {
 357                         SCSI_LOG_ERROR_RECOVERY(3,
 358                                 sdev_printk(KERN_INFO, sdev,
 359                                             "%s: cmds failed: %d, cancel: %d\n",
 360                                             __func__, cmd_failed,
 361                                             cmd_cancel));
 362                         cmd_cancel = 0;
 363                         cmd_failed = 0;
 364                         ++devices_failed;
 365                 }
 366         }
 367
 368         SCSI_LOG_ERROR_RECOVERY(2, shost_printk(KERN_INFO, shost,
 369                                    "Total of %d commands on %d"
 370                                    " devices require eh work\n",
 371                                    total_failures, devices_failed));
 372 }
 373 #endif
 374
 375  /**
 376  * scsi_report_lun_change - Set flag on all *other* devices on the same target
 377  *                          to indicate that a UNIT ATTENTION is expected.
 378  * @sdev:       Device reporting the UNIT ATTENTION
 379  */
 380 static void scsi_report_lun_change(struct scsi_device *sdev)
 381 {
 382         sdev->sdev_target->expecting_lun_change = 1;
 383 }
 384
 385 /**
 386  * scsi_report_sense - Examine scsi sense information and log messages for
 387  *                     certain conditions, also issue uevents for some of them.
 388  * @sdev:       Device reporting the sense code
 389  * @sshdr:      sshdr to be examined
 390  */
 391 static void scsi_report_sense(struct scsi_device *sdev,
 392                               struct scsi_sense_hdr *sshdr)
 393 {
 394         enum scsi_device_event evt_type = SDEV_EVT_MAXBITS;     /* i.e. none */
 395
 396         if (sshdr->sense_key == UNIT_ATTENTION) {
 397                 if (sshdr->asc == 0x3f && sshdr->ascq == 0x03) {
 398                         evt_type = SDEV_EVT_INQUIRY_CHANGE_REPORTED;
 399                         sdev_printk(KERN_WARNING, sdev,
 400                                     "Inquiry data has changed");
 401                 } else if (sshdr->asc == 0x3f && sshdr->ascq == 0x0e) {
 402                         evt_type = SDEV_EVT_LUN_CHANGE_REPORTED;
 403                         scsi_report_lun_change(sdev);
 404                         sdev_printk(KERN_WARNING, sdev,
 405                                     "Warning! Received an indication that the "
 406                                     "LUN assignments on this target have "
 407                                     "changed. The Linux SCSI layer does not "
 408                                     "automatically remap LUN assignments.\n");
 409                 } else if (sshdr->asc == 0x3f)
 410                         sdev_printk(KERN_WARNING, sdev,
 411                                     "Warning! Received an indication that the "
 412                                     "operating parameters on this target have "
 413                                     "changed. The Linux SCSI layer does not "
 414                                     "automatically adjust these parameters.\n");
 415
 416                 if (sshdr->asc == 0x38 && sshdr->ascq == 0x07) {
 417                         evt_type = SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED;
 418                         sdev_printk(KERN_WARNING, sdev,
 419                                     "Warning! Received an indication that the "
 420                                     "LUN reached a thin provisioning soft "
 421                                     "threshold.\n");
 422                 }
 423
 424                 if (sshdr->asc == 0x2a && sshdr->ascq == 0x01) {
 425                         evt_type = SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED;
 426                         sdev_printk(KERN_WARNING, sdev,
 427                                     "Mode parameters changed");
 428                 } else if (sshdr->asc == 0x2a && sshdr->ascq == 0x09) {
 429                         evt_type = SDEV_EVT_CAPACITY_CHANGE_REPORTED;
 430                         sdev_printk(KERN_WARNING, sdev,
 431                                     "Capacity data has changed");
 432                 } else if (sshdr->asc == 0x2a)
 433                         sdev_printk(KERN_WARNING, sdev,
 434                                     "Parameters changed");
 435         }
 436
 437         if (evt_type != SDEV_EVT_MAXBITS) {
 438                 set_bit(evt_type, sdev->pending_events);
 439                 schedule_work(&sdev->event_work);
 440         }
 441 }
 442
 443 /**
 444  * scsi_check_sense - Examine scsi cmd sense
 445  * @scmd:       Cmd to have sense checked.
 446  *
 447  * Return value:
 448  *      SUCCESS or FAILED or NEEDS_RETRY or ADD_TO_MLQUEUE
 449  *
 450  * Notes:
 451  *      When a deferred error is detected the current command has
 452  *      not been executed and needs retrying.
 453  */
 454 static int scsi_check_sense(struct scsi_cmnd *scmd)
 455 {
 456         struct scsi_device *sdev = scmd->device;
 457         struct scsi_sense_hdr sshdr;
 458
 459         if (! scsi_command_normalize_sense(scmd, &sshdr))
 460                 return FAILED;  /* no valid sense data */
 461
 462         if (scmd->cmnd[0] == TEST_UNIT_READY && scmd->scsi_done != scsi_eh_done)
 463                 /*
 464                  * nasty: for mid-layer issued TURs, we need to return the
 465                  * actual sense data without any recovery attempt.  For eh
 466                  * issued ones, we need to try to recover and interpret
 467                  */
 468                 return SUCCESS;
 469
 470         scsi_report_sense(sdev, &sshdr);
 471
 472         if (scsi_sense_is_deferred(&sshdr))
 473                 return NEEDS_RETRY;
 474
 475         if (sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh &&
 476                         sdev->scsi_dh_data->scsi_dh->check_sense) {
 477                 int rc;
 478
 479                 rc = sdev->scsi_dh_data->scsi_dh->check_sense(sdev, &sshdr);
 480                 if (rc != SCSI_RETURN_NOT_HANDLED)
 481                         return rc;
 482                 /* handler does not care. Drop down to default handling */
 483         }
 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
 606 static void scsi_handle_queue_ramp_up(struct scsi_device *sdev)
 607 {
 608         struct scsi_host_template *sht = sdev->host->hostt;
 609         struct scsi_device *tmp_sdev;
 610
 611         if (!sht->change_queue_depth ||
 612             sdev->queue_depth >= sdev->max_queue_depth)
 613                 return;
 614
 615         if (time_before(jiffies,
 616             sdev->last_queue_ramp_up + sdev->queue_ramp_up_period))
 617                 return;
 618
 619         if (time_before(jiffies,
 620             sdev->last_queue_full_time + sdev->queue_ramp_up_period))
 621                 return;
 622
 623         /*
 624          * Walk all devices of a target and do
 625          * ramp up on them.
 626          */
 627         shost_for_each_device(tmp_sdev, sdev->host) {
 628                 if (tmp_sdev->channel != sdev->channel ||
 629                     tmp_sdev->id != sdev->id ||
 630                     tmp_sdev->queue_depth == sdev->max_queue_depth)
 631                         continue;
 632                 /*
 633                  * call back into LLD to increase queue_depth by one
 634                  * with ramp up reason code.
 635                  */
 636                 sht->change_queue_depth(tmp_sdev, tmp_sdev->queue_depth + 1,
 637                                         SCSI_QDEPTH_RAMP_UP);
 638                 sdev->last_queue_ramp_up = jiffies;
 639         }
 640 }
 641
 642 static void scsi_handle_queue_full(struct scsi_device *sdev)
 643 {
 644         struct scsi_host_template *sht = sdev->host->hostt;
 645         struct scsi_device *tmp_sdev;
 646
 647         if (!sht->change_queue_depth)
 648                 return;
 649
 650         shost_for_each_device(tmp_sdev, sdev->host) {
 651                 if (tmp_sdev->channel != sdev->channel ||
 652                     tmp_sdev->id != sdev->id)
 653                         continue;
 654                 /*
 655                  * We do not know the number of commands that were at
 656                  * the device when we got the queue full so we start
 657                  * from the highest possible value and work our way down.
 658                  */
 659                 sht->change_queue_depth(tmp_sdev, tmp_sdev->queue_depth - 1,
 660                                         SCSI_QDEPTH_QFULL);
 661         }
 662 }
 663
 664 /**
 665  * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD.
 666  * @scmd:       SCSI cmd to examine.
 667  *
 668  * Notes:
 669  *    This is *only* called when we are examining the status of commands
 670  *    queued during error recovery.  the main difference here is that we
 671  *    don't allow for the possibility of retries here, and we are a lot
 672  *    more restrictive about what we consider acceptable.
 673  */
 674 static int scsi_eh_completed_normally(struct scsi_cmnd *scmd)
 675 {
 676         /*
 677          * first check the host byte, to see if there is anything in there
 678          * that would indicate what we need to do.
 679          */
 680         if (host_byte(scmd->result) == DID_RESET) {
 681                 /*
 682                  * rats.  we are already in the error handler, so we now
 683                  * get to try and figure out what to do next.  if the sense
 684                  * is valid, we have a pretty good idea of what to do.
 685                  * if not, we mark it as FAILED.
 686                  */
 687                 return scsi_check_sense(scmd);
 688         }
 689         if (host_byte(scmd->result) != DID_OK)
 690                 return FAILED;
 691
 692         /*
 693          * next, check the message byte.
 694          */
 695         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
 696                 return FAILED;
 697
 698         /*
 699          * now, check the status byte to see if this indicates
 700          * anything special.
 701          */
 702         switch (status_byte(scmd->result)) {
 703         case GOOD:
 704                 scsi_handle_queue_ramp_up(scmd->device);
 705         case COMMAND_TERMINATED:
 706                 return SUCCESS;
 707         case CHECK_CONDITION:
 708                 return scsi_check_sense(scmd);
 709         case CONDITION_GOOD:
 710         case INTERMEDIATE_GOOD:
 711         case INTERMEDIATE_C_GOOD:
 712                 /*
 713                  * who knows?  FIXME(eric)
 714                  */
 715                 return SUCCESS;
 716         case RESERVATION_CONFLICT:
 717                 if (scmd->cmnd[0] == TEST_UNIT_READY)
 718                         /* it is a success, we probed the device and
 719                          * found it */
 720                         return SUCCESS;
 721                 /* otherwise, we failed to send the command */
 722                 return FAILED;
 723         case QUEUE_FULL:
 724                 scsi_handle_queue_full(scmd->device);
 725                 /* fall through */
 726         case BUSY:
 727                 return NEEDS_RETRY;
 728         default:
 729                 return FAILED;
 730         }
 731         return FAILED;
 732 }
 733
 734 /**
 735  * scsi_eh_done - Completion function for error handling.
 736  * @scmd:       Cmd that is done.
 737  */
 738 static void scsi_eh_done(struct scsi_cmnd *scmd)
 739 {
 740         struct completion *eh_action;
 741
 742         SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
 743                         "%s scmd: %p result: %x\n",
 744                         __func__, scmd, scmd->result));
 745
 746         eh_action = scmd->device->host->eh_action;
 747         if (eh_action)
 748                 complete(eh_action);
 749 }
 750
 751 /**
 752  * scsi_try_host_reset - ask host adapter to reset itself
 753  * @scmd:       SCSI cmd to send host reset.
 754  */
 755 static int scsi_try_host_reset(struct scsi_cmnd *scmd)
 756 {
 757         unsigned long flags;
 758         int rtn;
 759         struct Scsi_Host *host = scmd->device->host;
 760         struct scsi_host_template *hostt = host->hostt;
 761
 762         SCSI_LOG_ERROR_RECOVERY(3,
 763                 shost_printk(KERN_INFO, host, "Snd Host RST\n"));
 764
 765         if (!hostt->eh_host_reset_handler)
 766                 return FAILED;
 767
 768         rtn = hostt->eh_host_reset_handler(scmd);
 769
 770         if (rtn == SUCCESS) {
 771                 if (!hostt->skip_settle_delay)
 772                         ssleep(HOST_RESET_SETTLE_TIME);
 773                 spin_lock_irqsave(host->host_lock, flags);
 774                 scsi_report_bus_reset(host, scmd_channel(scmd));
 775                 spin_unlock_irqrestore(host->host_lock, flags);
 776         }
 777
 778         return rtn;
 779 }
 780
 781 /**
 782  * scsi_try_bus_reset - ask host to perform a bus reset
 783  * @scmd:       SCSI cmd to send bus reset.
 784  */
 785 static int scsi_try_bus_reset(struct scsi_cmnd *scmd)
 786 {
 787         unsigned long flags;
 788         int rtn;
 789         struct Scsi_Host *host = scmd->device->host;
 790         struct scsi_host_template *hostt = host->hostt;
 791
 792         SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
 793                 "%s: Snd Bus RST\n", __func__));
 794
 795         if (!hostt->eh_bus_reset_handler)
 796                 return FAILED;
 797
 798         rtn = hostt->eh_bus_reset_handler(scmd);
 799
 800         if (rtn == SUCCESS) {
 801                 if (!hostt->skip_settle_delay)
 802                         ssleep(BUS_RESET_SETTLE_TIME);
 803                 spin_lock_irqsave(host->host_lock, flags);
 804                 scsi_report_bus_reset(host, scmd_channel(scmd));
 805                 spin_unlock_irqrestore(host->host_lock, flags);
 806         }
 807
 808         return rtn;
 809 }
 810
 811 static void __scsi_report_device_reset(struct scsi_device *sdev, void *data)
 812 {
 813         sdev->was_reset = 1;
 814         sdev->expecting_cc_ua = 1;
 815 }
 816
 817 /**
 818  * scsi_try_target_reset - Ask host to perform a target reset
 819  * @scmd:       SCSI cmd used to send a target reset
 820  *
 821  * Notes:
 822  *    There is no timeout for this operation.  if this operation is
 823  *    unreliable for a given host, then the host itself needs to put a
 824  *    timer on it, and set the host back to a consistent state prior to
 825  *    returning.
 826  */
 827 static int scsi_try_target_reset(struct scsi_cmnd *scmd)
 828 {
 829         unsigned long flags;
 830         int rtn;
 831         struct Scsi_Host *host = scmd->device->host;
 832         struct scsi_host_template *hostt = host->hostt;
 833
 834         if (!hostt->eh_target_reset_handler)
 835                 return FAILED;
 836
 837         rtn = hostt->eh_target_reset_handler(scmd);
 838         if (rtn == SUCCESS) {
 839                 spin_lock_irqsave(host->host_lock, flags);
 840                 __starget_for_each_device(scsi_target(scmd->device), NULL,
 841                                           __scsi_report_device_reset);
 842                 spin_unlock_irqrestore(host->host_lock, flags);
 843         }
 844
 845         return rtn;
 846 }
 847
 848 /**
 849  * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
 850  * @scmd:       SCSI cmd used to send BDR
 851  *
 852  * Notes:
 853  *    There is no timeout for this operation.  if this operation is
 854  *    unreliable for a given host, then the host itself needs to put a
 855  *    timer on it, and set the host back to a consistent state prior to
 856  *    returning.
 857  */
 858 static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
 859 {
 860         int rtn;
 861         struct scsi_host_template *hostt = scmd->device->host->hostt;
 862
 863         if (!hostt->eh_device_reset_handler)
 864                 return FAILED;
 865
 866         rtn = hostt->eh_device_reset_handler(scmd);
 867         if (rtn == SUCCESS)
 868                 __scsi_report_device_reset(scmd->device, NULL);
 869         return rtn;
 870 }
 871
 872 static int scsi_try_to_abort_cmd(struct scsi_host_template *hostt, struct scsi_cmnd *scmd)
 873 {
 874         if (!hostt->eh_abort_handler)
 875                 return FAILED;
 876
 877         return hostt->eh_abort_handler(scmd);
 878 }
 879
 880 static void scsi_abort_eh_cmnd(struct scsi_cmnd *scmd)
 881 {
 882         if (scsi_try_to_abort_cmd(scmd->device->host->hostt, scmd) != SUCCESS)
 883                 if (scsi_try_bus_device_reset(scmd) != SUCCESS)
 884                         if (scsi_try_target_reset(scmd) != SUCCESS)
 885                                 if (scsi_try_bus_reset(scmd) != SUCCESS)
 886                                         scsi_try_host_reset(scmd);
 887 }
 888
 889 /**
 890  * scsi_eh_prep_cmnd  - Save a scsi command info as part of error recovery
 891  * @scmd:       SCSI command structure to hijack
 892  * @ses:        structure to save restore information
 893  * @cmnd:       CDB to send. Can be NULL if no new cmnd is needed
 894  * @cmnd_size:  size in bytes of @cmnd (must be <= BLK_MAX_CDB)
 895  * @sense_bytes: size of sense data to copy. or 0 (if != 0 @cmnd is ignored)
 896  *
 897  * This function is used to save a scsi command information before re-execution
 898  * as part of the error recovery process.  If @sense_bytes is 0 the command
 899  * sent must be one that does not transfer any data.  If @sense_bytes != 0
 900  * @cmnd is ignored and this functions sets up a REQUEST_SENSE command
 901  * and cmnd buffers to read @sense_bytes into @scmd->sense_buffer.
 902  */
 903 void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses,
 904                         unsigned char *cmnd, int cmnd_size, unsigned sense_bytes)
 905 {
 906         struct scsi_device *sdev = scmd->device;
 907
 908         /*
 909          * We need saved copies of a number of fields - this is because
 910          * error handling may need to overwrite these with different values
 911          * to run different commands, and once error handling is complete,
 912          * we will need to restore these values prior to running the actual
 913          * command.
 914          */
 915         ses->cmd_len = scmd->cmd_len;
 916         ses->cmnd = scmd->cmnd;
 917         ses->data_direction = scmd->sc_data_direction;
 918         ses->sdb = scmd->sdb;
 919         ses->next_rq = scmd->request->next_rq;
 920         ses->result = scmd->result;
 921         ses->underflow = scmd->underflow;
 922         ses->prot_op = scmd->prot_op;
 923
 924         scmd->prot_op = SCSI_PROT_NORMAL;
 925         scmd->eh_eflags = 0;
 926         scmd->cmnd = ses->eh_cmnd;
 927         memset(scmd->cmnd, 0, BLK_MAX_CDB);
 928         memset(&scmd->sdb, 0, sizeof(scmd->sdb));
 929         scmd->request->next_rq = NULL;
 930         scmd->result = 0;
 931
 932         if (sense_bytes) {
 933                 scmd->sdb.length = min_t(unsigned, SCSI_SENSE_BUFFERSIZE,
 934                                          sense_bytes);
 935                 sg_init_one(&ses->sense_sgl, scmd->sense_buffer,
 936                             scmd->sdb.length);
 937                 scmd->sdb.table.sgl = &ses->sense_sgl;
 938                 scmd->sc_data_direction = DMA_FROM_DEVICE;
 939                 scmd->sdb.table.nents = 1;
 940                 scmd->cmnd[0] = REQUEST_SENSE;
 941                 scmd->cmnd[4] = scmd->sdb.length;
 942                 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
 943         } else {
 944                 scmd->sc_data_direction = DMA_NONE;
 945                 if (cmnd) {
 946                         BUG_ON(cmnd_size > BLK_MAX_CDB);
 947                         memcpy(scmd->cmnd, cmnd, cmnd_size);
 948                         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
 949                 }
 950         }
 951
 952         scmd->underflow = 0;
 953
 954         if (sdev->scsi_level <= SCSI_2 && sdev->scsi_level != SCSI_UNKNOWN)
 955                 scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
 956                         (sdev->lun << 5 & 0xe0);
 957
 958         /*
 959          * Zero the sense buffer.  The scsi spec mandates that any
 960          * untransferred sense data should be interpreted as being zero.
 961          */
 962         memset(scmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
 963 }
 964 EXPORT_SYMBOL(scsi_eh_prep_cmnd);
 965
 966 /**
 967  * scsi_eh_restore_cmnd  - Restore a scsi command info as part of error recovery
 968  * @scmd:       SCSI command structure to restore
 969  * @ses:        saved information from a coresponding call to scsi_eh_prep_cmnd
 970  *
 971  * Undo any damage done by above scsi_eh_prep_cmnd().
 972  */
 973 void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct scsi_eh_save *ses)
 974 {
 975         /*
 976          * Restore original data
 977          */
 978         scmd->cmd_len = ses->cmd_len;
 979         scmd->cmnd = ses->cmnd;
 980         scmd->sc_data_direction = ses->data_direction;
 981         scmd->sdb = ses->sdb;
 982         scmd->request->next_rq = ses->next_rq;
 983         scmd->result = ses->result;
 984         scmd->underflow = ses->underflow;
 985         scmd->prot_op = ses->prot_op;
 986 }
 987 EXPORT_SYMBOL(scsi_eh_restore_cmnd);
 988
 989 /**
 990  * scsi_send_eh_cmnd  - submit a scsi command as part of error recovery
 991  * @scmd:       SCSI command structure to hijack
 992  * @cmnd:       CDB to send
 993  * @cmnd_size:  size in bytes of @cmnd
 994  * @timeout:    timeout for this request
 995  * @sense_bytes: size of sense data to copy or 0
 996  *
 997  * This function is used to send a scsi command down to a target device
 998  * as part of the error recovery process. See also scsi_eh_prep_cmnd() above.
 999  *
1000  * Return value:
1001  *    SUCCESS or FAILED or NEEDS_RETRY
1002  */
1003 static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd,
1004                              int cmnd_size, int timeout, unsigned sense_bytes)
1005 {
1006         struct scsi_device *sdev = scmd->device;
1007         struct Scsi_Host *shost = sdev->host;
1008         DECLARE_COMPLETION_ONSTACK(done);
1009         unsigned long timeleft = timeout;
1010         struct scsi_eh_save ses;
1011         const unsigned long stall_for = msecs_to_jiffies(100);
1012         int rtn;
1013
1014 retry:
1015         scsi_eh_prep_cmnd(scmd, &ses, cmnd, cmnd_size, sense_bytes);
1016         shost->eh_action = &done;
1017
1018         scsi_log_send(scmd);
1019         scmd->scsi_done = scsi_eh_done;
1020         rtn = shost->hostt->queuecommand(shost, scmd);
1021         if (rtn) {
1022                 if (timeleft > stall_for) {
1023                         scsi_eh_restore_cmnd(scmd, &ses);
1024                         timeleft -= stall_for;
1025                         msleep(jiffies_to_msecs(stall_for));
1026                         goto retry;
1027                 }
1028                 /* signal not to enter either branch of the if () below */
1029                 timeleft = 0;
1030                 rtn = NEEDS_RETRY;
1031         } else {
1032                 timeleft = wait_for_completion_timeout(&done, timeout);
1033                 rtn = SUCCESS;
1034         }
1035
1036         shost->eh_action = NULL;
1037
1038         scsi_log_completion(scmd, rtn);
1039
1040         SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1041                         "%s: scmd: %p, timeleft: %ld\n",
1042                         __func__, scmd, timeleft));
1043
1044         /*
1045          * If there is time left scsi_eh_done got called, and we will examine
1046          * the actual status codes to see whether the command actually did
1047          * complete normally, else if we have a zero return and no time left,
1048          * the command must still be pending, so abort it and return FAILED.
1049          * If we never actually managed to issue the command, because
1050          * ->queuecommand() kept returning non zero, use the rtn = FAILED
1051          * value above (so don't execute either branch of the if)
1052          */
1053         if (timeleft) {
1054                 rtn = scsi_eh_completed_normally(scmd);
1055                 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1056                         "%s: scsi_eh_completed_normally %x\n", __func__, rtn));
1057
1058                 switch (rtn) {
1059                 case SUCCESS:
1060                 case NEEDS_RETRY:
1061                 case FAILED:
1062                         break;
1063                 case ADD_TO_MLQUEUE:
1064                         rtn = NEEDS_RETRY;
1065                         break;
1066                 default:
1067                         rtn = FAILED;
1068                         break;
1069                 }
1070         } else if (!rtn) {
1071                 scsi_abort_eh_cmnd(scmd);
1072                 rtn = FAILED;
1073         }
1074
1075         scsi_eh_restore_cmnd(scmd, &ses);
1076
1077         return rtn;
1078 }
1079
1080 /**
1081  * scsi_request_sense - Request sense data from a particular target.
1082  * @scmd:       SCSI cmd for request sense.
1083  *
1084  * Notes:
1085  *    Some hosts automatically obtain this information, others require
1086  *    that we obtain it on our own. This function will *not* return until
1087  *    the command either times out, or it completes.
1088  */
1089 static int scsi_request_sense(struct scsi_cmnd *scmd)
1090 {
1091         return scsi_send_eh_cmnd(scmd, NULL, 0, scmd->device->eh_timeout, ~0);
1092 }
1093
1094 static int scsi_eh_action(struct scsi_cmnd *scmd, int rtn)
1095 {
1096         if (scmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
1097                 struct scsi_driver *sdrv = scsi_cmd_to_driver(scmd);
1098                 if (sdrv->eh_action)
1099                         rtn = sdrv->eh_action(scmd, rtn);
1100         }
1101         return rtn;
1102 }
1103
1104 /**
1105  * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
1106  * @scmd:       Original SCSI cmd that eh has finished.
1107  * @done_q:     Queue for processed commands.
1108  *
1109  * Notes:
1110  *    We don't want to use the normal command completion while we are are
1111  *    still handling errors - it may cause other commands to be queued,
1112  *    and that would disturb what we are doing.  Thus we really want to
1113  *    keep a list of pending commands for final completion, and once we
1114  *    are ready to leave error handling we handle completion for real.
1115  */
1116 void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)
1117 {
1118         scmd->device->host->host_failed--;
1119         scmd->eh_eflags = 0;
1120         list_move_tail(&scmd->eh_entry, done_q);
1121 }
1122 EXPORT_SYMBOL(scsi_eh_finish_cmd);
1123
1124 /**
1125  * scsi_eh_get_sense - Get device sense data.
1126  * @work_q:     Queue of commands to process.
1127  * @done_q:     Queue of processed commands.
1128  *
1129  * Description:
1130  *    See if we need to request sense information.  if so, then get it
1131  *    now, so we have a better idea of what to do.
1132  *
1133  * Notes:
1134  *    This has the unfortunate side effect that if a shost adapter does
1135  *    not automatically request sense information, we end up shutting
1136  *    it down before we request it.
1137  *
1138  *    All drivers should request sense information internally these days,
1139  *    so for now all I have to say is tough noogies if you end up in here.
1140  *
1141  *    XXX: Long term this code should go away, but that needs an audit of
1142  *         all LLDDs first.
1143  */
1144 int scsi_eh_get_sense(struct list_head *work_q,
1145                       struct list_head *done_q)
1146 {
1147         struct scsi_cmnd *scmd, *next;
1148         struct Scsi_Host *shost;
1149         int rtn;
1150
1151         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1152                 if ((scmd->eh_eflags & SCSI_EH_CANCEL_CMD) ||
1153                     SCSI_SENSE_VALID(scmd))
1154                         continue;
1155
1156                 shost = scmd->device->host;
1157                 if (scsi_host_eh_past_deadline(shost)) {
1158                         SCSI_LOG_ERROR_RECOVERY(3,
1159                                 shost_printk(KERN_INFO, shost,
1160                                             "skip %s, past eh deadline\n",
1161                                              __func__));
1162                         break;
1163                 }
1164                 if (status_byte(scmd->result) != CHECK_CONDITION)
1165                         /*
1166                          * don't request sense if there's no check condition
1167                          * status because the error we're processing isn't one
1168                          * that has a sense code (and some devices get
1169                          * confused by sense requests out of the blue)
1170                          */
1171                         continue;
1172
1173                 SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd,
1174                                                   "%s: requesting sense\n",
1175                                                   current->comm));
1176                 rtn = scsi_request_sense(scmd);
1177                 if (rtn != SUCCESS)
1178                         continue;
1179
1180                 SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1181                         "sense requested for %p result %x\n",
1182                         scmd, scmd->result));
1183                 SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense("bh", scmd));
1184
1185                 rtn = scsi_decide_disposition(scmd);
1186
1187                 /*
1188                  * if the result was normal, then just pass it along to the
1189                  * upper level.
1190                  */
1191                 if (rtn == SUCCESS)
1192                         /* we don't want this command reissued, just
1193                          * finished with the sense data, so set
1194                          * retries to the max allowed to ensure it
1195                          * won't get reissued */
1196                         scmd->retries = scmd->allowed;
1197                 else if (rtn != NEEDS_RETRY)
1198                         continue;
1199
1200                 scsi_eh_finish_cmd(scmd, done_q);
1201         }
1202
1203         return list_empty(work_q);
1204 }
1205 EXPORT_SYMBOL_GPL(scsi_eh_get_sense);
1206
1207 /**
1208  * scsi_eh_tur - Send TUR to device.
1209  * @scmd:       &scsi_cmnd to send TUR
1210  *
1211  * Return value:
1212  *    0 - Device is ready. 1 - Device NOT ready.
1213  */
1214 static int scsi_eh_tur(struct scsi_cmnd *scmd)
1215 {
1216         static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
1217         int retry_cnt = 1, rtn;
1218
1219 retry_tur:
1220         rtn = scsi_send_eh_cmnd(scmd, tur_command, 6,
1221                                 scmd->device->eh_timeout, 0);
1222
1223         SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1224                 "%s: scmd %p rtn %x\n", __func__, scmd, rtn));
1225
1226         switch (rtn) {
1227         case NEEDS_RETRY:
1228                 if (retry_cnt--)
1229                         goto retry_tur;
1230                 /*FALLTHRU*/
1231         case SUCCESS:
1232                 return 0;
1233         default:
1234                 return 1;
1235         }
1236 }
1237
1238 /**
1239  * scsi_eh_test_devices - check if devices are responding from error recovery.
1240  * @cmd_list:   scsi commands in error recovery.
1241  * @work_q:     queue for commands which still need more error recovery
1242  * @done_q:     queue for commands which are finished
1243  * @try_stu:    boolean on if a STU command should be tried in addition to TUR.
1244  *
1245  * Decription:
1246  *    Tests if devices are in a working state.  Commands to devices now in
1247  *    a working state are sent to the done_q while commands to devices which
1248  *    are still failing to respond are returned to the work_q for more
1249  *    processing.
1250  **/
1251 static int scsi_eh_test_devices(struct list_head *cmd_list,
1252                                 struct list_head *work_q,
1253                                 struct list_head *done_q, int try_stu)
1254 {
1255         struct scsi_cmnd *scmd, *next;
1256         struct scsi_device *sdev;
1257         int finish_cmds;
1258
1259         while (!list_empty(cmd_list)) {
1260                 scmd = list_entry(cmd_list->next, struct scsi_cmnd, eh_entry);
1261                 sdev = scmd->device;
1262
1263                 if (!try_stu) {
1264                         if (scsi_host_eh_past_deadline(sdev->host)) {
1265                                 /* Push items back onto work_q */
1266                                 list_splice_init(cmd_list, work_q);
1267                                 SCSI_LOG_ERROR_RECOVERY(3,
1268                                         shost_printk(KERN_INFO, sdev->host,
1269                                                      "skip %s, past eh deadline",
1270                                                      __func__));
1271                                 break;
1272                         }
1273                 }
1274
1275                 finish_cmds = !scsi_device_online(scmd->device) ||
1276                         (try_stu && !scsi_eh_try_stu(scmd) &&
1277                          !scsi_eh_tur(scmd)) ||
1278                         !scsi_eh_tur(scmd);
1279
1280                 list_for_each_entry_safe(scmd, next, cmd_list, eh_entry)
1281                         if (scmd->device == sdev) {
1282                                 if (finish_cmds &&
1283                                     (try_stu ||
1284                                      scsi_eh_action(scmd, SUCCESS) == SUCCESS))
1285                                         scsi_eh_finish_cmd(scmd, done_q);
1286                                 else
1287                                         list_move_tail(&scmd->eh_entry, work_q);
1288                         }
1289         }
1290         return list_empty(work_q);
1291 }
1292
1293
1294 /**
1295  * scsi_eh_abort_cmds - abort pending commands.
1296  * @work_q:     &list_head for pending commands.
1297  * @done_q:     &list_head for processed commands.
1298  *
1299  * Decription:
1300  *    Try and see whether or not it makes sense to try and abort the
1301  *    running command.  This only works out to be the case if we have one
1302  *    command that has timed out.  If the command simply failed, it makes
1303  *    no sense to try and abort the command, since as far as the shost
1304  *    adapter is concerned, it isn't running.
1305  */
1306 static int scsi_eh_abort_cmds(struct list_head *work_q,
1307                               struct list_head *done_q)
1308 {
1309         struct scsi_cmnd *scmd, *next;
1310         LIST_HEAD(check_list);
1311         int rtn;
1312         struct Scsi_Host *shost;
1313
1314         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1315                 if (!(scmd->eh_eflags & SCSI_EH_CANCEL_CMD))
1316                         continue;
1317                 shost = scmd->device->host;
1318                 if (scsi_host_eh_past_deadline(shost)) {
1319                         list_splice_init(&check_list, work_q);
1320                         SCSI_LOG_ERROR_RECOVERY(3,
1321                                 shost_printk(KERN_INFO, shost,
1322                                             "skip %s, past eh deadline\n",
1323                                              __func__));
1324                         return list_empty(work_q);
1325                 }
1326                 SCSI_LOG_ERROR_RECOVERY(3,
1327                         shost_printk(KERN_INFO, shost,
1328                                      "%s: aborting cmd: 0x%p\n",
1329                                      current->comm, scmd));
1330                 rtn = scsi_try_to_abort_cmd(shost->hostt, scmd);
1331                 if (rtn == FAILED) {
1332                         SCSI_LOG_ERROR_RECOVERY(3,
1333                                 shost_printk(KERN_INFO, shost,
1334                                              "%s: aborting cmd failed: 0x%p\n",
1335                                              current->comm, scmd));
1336                         list_splice_init(&check_list, work_q);
1337                         return list_empty(work_q);
1338                 }
1339                 scmd->eh_eflags &= ~SCSI_EH_CANCEL_CMD;
1340                 if (rtn == FAST_IO_FAIL)
1341                         scsi_eh_finish_cmd(scmd, done_q);
1342                 else
1343                         list_move_tail(&scmd->eh_entry, &check_list);
1344         }
1345
1346         return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1347 }
1348
1349 /**
1350  * scsi_eh_try_stu - Send START_UNIT to device.
1351  * @scmd:       &scsi_cmnd to send START_UNIT
1352  *
1353  * Return value:
1354  *    0 - Device is ready. 1 - Device NOT ready.
1355  */
1356 static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
1357 {
1358         static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
1359
1360         if (scmd->device->allow_restart) {
1361                 int i, rtn = NEEDS_RETRY;
1362
1363                 for (i = 0; rtn == NEEDS_RETRY && i < 2; i++)
1364                         rtn = scsi_send_eh_cmnd(scmd, stu_command, 6, scmd->device->request_queue->rq_timeout, 0);
1365
1366                 if (rtn == SUCCESS)
1367                         return 0;
1368         }
1369
1370         return 1;
1371 }
1372
1373  /**
1374  * scsi_eh_stu - send START_UNIT if needed
1375  * @shost:      &scsi host being recovered.
1376  * @work_q:     &list_head for pending commands.
1377  * @done_q:     &list_head for processed commands.
1378  *
1379  * Notes:
1380  *    If commands are failing due to not ready, initializing command required,
1381  *      try revalidating the device, which will end up sending a start unit.
1382  */
1383 static int scsi_eh_stu(struct Scsi_Host *shost,
1384                               struct list_head *work_q,
1385                               struct list_head *done_q)
1386 {
1387         struct scsi_cmnd *scmd, *stu_scmd, *next;
1388         struct scsi_device *sdev;
1389
1390         shost_for_each_device(sdev, shost) {
1391                 if (scsi_host_eh_past_deadline(shost)) {
1392                         SCSI_LOG_ERROR_RECOVERY(3,
1393                                 shost_printk(KERN_INFO, shost,
1394                                             "skip %s, past eh deadline\n",
1395                                              __func__));
1396                         break;
1397                 }
1398                 stu_scmd = NULL;
1399                 list_for_each_entry(scmd, work_q, eh_entry)
1400                         if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
1401                             scsi_check_sense(scmd) == FAILED ) {
1402                                 stu_scmd = scmd;
1403                                 break;
1404                         }
1405
1406                 if (!stu_scmd)
1407                         continue;
1408
1409                 SCSI_LOG_ERROR_RECOVERY(3,
1410                         shost_printk(KERN_INFO, shost,
1411                                      "%s: Sending START_UNIT to sdev: 0x%p\n",
1412                                      current->comm, sdev));
1413
1414                 if (!scsi_eh_try_stu(stu_scmd)) {
1415                         if (!scsi_device_online(sdev) ||
1416                             !scsi_eh_tur(stu_scmd)) {
1417                                 list_for_each_entry_safe(scmd, next,
1418                                                           work_q, eh_entry) {
1419                                         if (scmd->device == sdev &&
1420                                             scsi_eh_action(scmd, SUCCESS) == SUCCESS)
1421                                                 scsi_eh_finish_cmd(scmd, done_q);
1422                                 }
1423                         }
1424                 } else {
1425                         SCSI_LOG_ERROR_RECOVERY(3,
1426                                 shost_printk(KERN_INFO, shost,
1427                                              "%s: START_UNIT failed to sdev:"
1428                                              " 0x%p\n", current->comm, sdev));
1429                 }
1430         }
1431
1432         return list_empty(work_q);
1433 }
1434
1435
1436 /**
1437  * scsi_eh_bus_device_reset - send bdr if needed
1438  * @shost:      scsi host being recovered.
1439  * @work_q:     &list_head for pending commands.
1440  * @done_q:     &list_head for processed commands.
1441  *
1442  * Notes:
1443  *    Try a bus device reset.  Still, look to see whether we have multiple
1444  *    devices that are jammed or not - if we have multiple devices, it
1445  *    makes no sense to try bus_device_reset - we really would need to try
1446  *    a bus_reset instead.
1447  */
1448 static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
1449                                     struct list_head *work_q,
1450                                     struct list_head *done_q)
1451 {
1452         struct scsi_cmnd *scmd, *bdr_scmd, *next;
1453         struct scsi_device *sdev;
1454         int rtn;
1455
1456         shost_for_each_device(sdev, shost) {
1457                 if (scsi_host_eh_past_deadline(shost)) {
1458                         SCSI_LOG_ERROR_RECOVERY(3,
1459                                 shost_printk(KERN_INFO, shost,
1460                                             "skip %s, past eh deadline\n",
1461                                              __func__));
1462                         break;
1463                 }
1464                 bdr_scmd = NULL;
1465                 list_for_each_entry(scmd, work_q, eh_entry)
1466                         if (scmd->device == sdev) {
1467                                 bdr_scmd = scmd;
1468                                 break;
1469                         }
1470
1471                 if (!bdr_scmd)
1472                         continue;
1473
1474                 SCSI_LOG_ERROR_RECOVERY(3,
1475                         shost_printk(KERN_INFO, shost,
1476                                      "%s: Sending BDR sdev: 0x%p\n",
1477                                      current->comm, sdev));
1478                 rtn = scsi_try_bus_device_reset(bdr_scmd);
1479                 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1480                         if (!scsi_device_online(sdev) ||
1481                             rtn == FAST_IO_FAIL ||
1482                             !scsi_eh_tur(bdr_scmd)) {
1483                                 list_for_each_entry_safe(scmd, next,
1484                                                          work_q, eh_entry) {
1485                                         if (scmd->device == sdev &&
1486                                             scsi_eh_action(scmd, rtn) != FAILED)
1487                                                 scsi_eh_finish_cmd(scmd,
1488                                                                    done_q);
1489                                 }
1490                         }
1491                 } else {
1492                         SCSI_LOG_ERROR_RECOVERY(3,
1493                                 shost_printk(KERN_INFO, shost,
1494                                              "%s: BDR failed sdev: 0x%p\n",
1495                                              current->comm, sdev));
1496                 }
1497         }
1498
1499         return list_empty(work_q);
1500 }
1501
1502 /**
1503  * scsi_eh_target_reset - send target reset if needed
1504  * @shost:      scsi host being recovered.
1505  * @work_q:     &list_head for pending commands.
1506  * @done_q:     &list_head for processed commands.
1507  *
1508  * Notes:
1509  *    Try a target reset.
1510  */
1511 static int scsi_eh_target_reset(struct Scsi_Host *shost,
1512                                 struct list_head *work_q,
1513                                 struct list_head *done_q)
1514 {
1515         LIST_HEAD(tmp_list);
1516         LIST_HEAD(check_list);
1517
1518         list_splice_init(work_q, &tmp_list);
1519
1520         while (!list_empty(&tmp_list)) {
1521                 struct scsi_cmnd *next, *scmd;
1522                 int rtn;
1523                 unsigned int id;
1524
1525                 if (scsi_host_eh_past_deadline(shost)) {
1526                         /* push back on work queue for further processing */
1527                         list_splice_init(&check_list, work_q);
1528                         list_splice_init(&tmp_list, work_q);
1529                         SCSI_LOG_ERROR_RECOVERY(3,
1530                                 shost_printk(KERN_INFO, shost,
1531                                             "skip %s, past eh deadline\n",
1532                                              __func__));
1533                         return list_empty(work_q);
1534                 }
1535
1536                 scmd = list_entry(tmp_list.next, struct scsi_cmnd, eh_entry);
1537                 id = scmd_id(scmd);
1538
1539                 SCSI_LOG_ERROR_RECOVERY(3,
1540                         shost_printk(KERN_INFO, shost,
1541                                      "%s: Sending target reset to target %d\n",
1542                                      current->comm, id));
1543                 rtn = scsi_try_target_reset(scmd);
1544                 if (rtn != SUCCESS && rtn != FAST_IO_FAIL)
1545                         SCSI_LOG_ERROR_RECOVERY(3,
1546                                 shost_printk(KERN_INFO, shost,
1547                                              "%s: Target reset failed"
1548                                              " target: %d\n",
1549                                              current->comm, id));
1550                 list_for_each_entry_safe(scmd, next, &tmp_list, eh_entry) {
1551                         if (scmd_id(scmd) != id)
1552                                 continue;
1553
1554                         if (rtn == SUCCESS)
1555                                 list_move_tail(&scmd->eh_entry, &check_list);
1556                         else if (rtn == FAST_IO_FAIL)
1557                                 scsi_eh_finish_cmd(scmd, done_q);
1558                         else
1559                                 /* push back on work queue for further processing */
1560                                 list_move(&scmd->eh_entry, work_q);
1561                 }
1562         }
1563
1564         return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1565 }
1566
1567 /**
1568  * scsi_eh_bus_reset - send a bus reset
1569  * @shost:      &scsi host being recovered.
1570  * @work_q:     &list_head for pending commands.
1571  * @done_q:     &list_head for processed commands.
1572  */
1573 static int scsi_eh_bus_reset(struct Scsi_Host *shost,
1574                              struct list_head *work_q,
1575                              struct list_head *done_q)
1576 {
1577         struct scsi_cmnd *scmd, *chan_scmd, *next;
1578         LIST_HEAD(check_list);
1579         unsigned int channel;
1580         int rtn;
1581
1582         /*
1583          * we really want to loop over the various channels, and do this on
1584          * a channel by channel basis.  we should also check to see if any
1585          * of the failed commands are on soft_reset devices, and if so, skip
1586          * the reset.
1587          */
1588
1589         for (channel = 0; channel <= shost->max_channel; channel++) {
1590                 if (scsi_host_eh_past_deadline(shost)) {
1591                         list_splice_init(&check_list, work_q);
1592                         SCSI_LOG_ERROR_RECOVERY(3,
1593                                 shost_printk(KERN_INFO, shost,
1594                                             "skip %s, past eh deadline\n",
1595                                              __func__));
1596                         return list_empty(work_q);
1597                 }
1598
1599                 chan_scmd = NULL;
1600                 list_for_each_entry(scmd, work_q, eh_entry) {
1601                         if (channel == scmd_channel(scmd)) {
1602                                 chan_scmd = scmd;
1603                                 break;
1604                                 /*
1605                                  * FIXME add back in some support for
1606                                  * soft_reset devices.
1607                                  */
1608                         }
1609                 }
1610
1611                 if (!chan_scmd)
1612                         continue;
1613                 SCSI_LOG_ERROR_RECOVERY(3,
1614                         shost_printk(KERN_INFO, shost,
1615                                      "%s: Sending BRST chan: %d\n",
1616                                      current->comm, channel));
1617                 rtn = scsi_try_bus_reset(chan_scmd);
1618                 if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1619                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1620                                 if (channel == scmd_channel(scmd)) {
1621                                         if (rtn == FAST_IO_FAIL)
1622                                                 scsi_eh_finish_cmd(scmd,
1623                                                                    done_q);
1624                                         else
1625                                                 list_move_tail(&scmd->eh_entry,
1626                                                                &check_list);
1627                                 }
1628                         }
1629                 } else {
1630                         SCSI_LOG_ERROR_RECOVERY(3,
1631                                 shost_printk(KERN_INFO, shost,
1632                                              "%s: BRST failed chan: %d\n",
1633                                              current->comm, channel));
1634                 }
1635         }
1636         return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1637 }
1638
1639 /**
1640  * scsi_eh_host_reset - send a host reset
1641  * @shost:      host to be reset.
1642  * @work_q:     &list_head for pending commands.
1643  * @done_q:     &list_head for processed commands.
1644  */
1645 static int scsi_eh_host_reset(struct Scsi_Host *shost,
1646                               struct list_head *work_q,
1647                               struct list_head *done_q)
1648 {
1649         struct scsi_cmnd *scmd, *next;
1650         LIST_HEAD(check_list);
1651         int rtn;
1652
1653         if (!list_empty(work_q)) {
1654                 scmd = list_entry(work_q->next,
1655                                   struct scsi_cmnd, eh_entry);
1656
1657                 SCSI_LOG_ERROR_RECOVERY(3,
1658                         shost_printk(KERN_INFO, shost,
1659                                      "%s: Sending HRST\n",
1660                                      current->comm));
1661
1662                 rtn = scsi_try_host_reset(scmd);
1663                 if (rtn == SUCCESS) {
1664                         list_splice_init(work_q, &check_list);
1665                 } else if (rtn == FAST_IO_FAIL) {
1666                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1667                                         scsi_eh_finish_cmd(scmd, done_q);
1668                         }
1669                 } else {
1670                         SCSI_LOG_ERROR_RECOVERY(3,
1671                                 shost_printk(KERN_INFO, shost,
1672                                              "%s: HRST failed\n",
1673                                              current->comm));
1674                 }
1675         }
1676         return scsi_eh_test_devices(&check_list, work_q, done_q, 1);
1677 }
1678
1679 /**
1680  * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
1681  * @work_q:     &list_head for pending commands.
1682  * @done_q:     &list_head for processed commands.
1683  */
1684 static void scsi_eh_offline_sdevs(struct list_head *work_q,
1685                                   struct list_head *done_q)
1686 {
1687         struct scsi_cmnd *scmd, *next;
1688
1689         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1690                 sdev_printk(KERN_INFO, scmd->device, "Device offlined - "
1691                             "not ready after error recovery\n");
1692                 scsi_device_set_state(scmd->device, SDEV_OFFLINE);
1693                 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD) {
1694                         /*
1695                          * FIXME: Handle lost cmds.
1696                          */
1697                 }
1698                 scsi_eh_finish_cmd(scmd, done_q);
1699         }
1700         return;
1701 }
1702
1703 /**
1704  * scsi_noretry_cmd - determine if command should be failed fast
1705  * @scmd:       SCSI cmd to examine.
1706  */
1707 int scsi_noretry_cmd(struct scsi_cmnd *scmd)
1708 {
1709         switch (host_byte(scmd->result)) {
1710         case DID_OK:
1711                 break;
1712         case DID_TIME_OUT:
1713                 goto check_type;
1714         case DID_BUS_BUSY:
1715                 return (scmd->request->cmd_flags & REQ_FAILFAST_TRANSPORT);
1716         case DID_PARITY:
1717                 return (scmd->request->cmd_flags & REQ_FAILFAST_DEV);
1718         case DID_ERROR:
1719                 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1720                     status_byte(scmd->result) == RESERVATION_CONFLICT)
1721                         return 0;
1722                 /* fall through */
1723         case DID_SOFT_ERROR:
1724                 return (scmd->request->cmd_flags & REQ_FAILFAST_DRIVER);
1725         }
1726
1727         if (status_byte(scmd->result) != CHECK_CONDITION)
1728                 return 0;
1729
1730 check_type:
1731         /*
1732          * assume caller has checked sense and determined
1733          * the check condition was retryable.
1734          */
1735         if (scmd->request->cmd_flags & REQ_FAILFAST_DEV ||
1736             scmd->request->cmd_type == REQ_TYPE_BLOCK_PC)
1737                 return 1;
1738         else
1739                 return 0;
1740 }
1741
1742 /**
1743  * scsi_decide_disposition - Disposition a cmd on return from LLD.
1744  * @scmd:       SCSI cmd to examine.
1745  *
1746  * Notes:
1747  *    This is *only* called when we are examining the status after sending
1748  *    out the actual data command.  any commands that are queued for error
1749  *    recovery (e.g. test_unit_ready) do *not* come through here.
1750  *
1751  *    When this routine returns failed, it means the error handler thread
1752  *    is woken.  In cases where the error code indicates an error that
1753  *    doesn't require the error handler read (i.e. we don't need to
1754  *    abort/reset), this function should return SUCCESS.
1755  */
1756 int scsi_decide_disposition(struct scsi_cmnd *scmd)
1757 {
1758         int rtn;
1759
1760         /*
1761          * if the device is offline, then we clearly just pass the result back
1762          * up to the top level.
1763          */
1764         if (!scsi_device_online(scmd->device)) {
1765                 SCSI_LOG_ERROR_RECOVERY(5, scmd_printk(KERN_INFO, scmd,
1766                         "%s: device offline - report as SUCCESS\n", __func__));
1767                 return SUCCESS;
1768         }
1769
1770         /*
1771          * first check the host byte, to see if there is anything in there
1772          * that would indicate what we need to do.
1773          */
1774         switch (host_byte(scmd->result)) {
1775         case DID_PASSTHROUGH:
1776                 /*
1777                  * no matter what, pass this through to the upper layer.
1778                  * nuke this special code so that it looks like we are saying
1779                  * did_ok.
1780                  */
1781                 scmd->result &= 0xff00ffff;
1782                 return SUCCESS;
1783         case DID_OK:
1784                 /*
1785                  * looks good.  drop through, and check the next byte.
1786                  */
1787                 break;
1788         case DID_ABORT:
1789                 if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) {
1790                         set_host_byte(scmd, DID_TIME_OUT);
1791                         return SUCCESS;
1792                 }
1793         case DID_NO_CONNECT:
1794         case DID_BAD_TARGET:
1795                 /*
1796                  * note - this means that we just report the status back
1797                  * to the top level driver, not that we actually think
1798                  * that it indicates SUCCESS.
1799                  */
1800                 return SUCCESS;
1801                 /*
1802                  * when the low level driver returns did_soft_error,
1803                  * it is responsible for keeping an internal retry counter
1804                  * in order to avoid endless loops (db)
1805                  *
1806                  * actually this is a bug in this function here.  we should
1807                  * be mindful of the maximum number of retries specified
1808                  * and not get stuck in a loop.
1809                  */
1810         case DID_SOFT_ERROR:
1811                 goto maybe_retry;
1812         case DID_IMM_RETRY:
1813                 return NEEDS_RETRY;
1814
1815         case DID_REQUEUE:
1816                 return ADD_TO_MLQUEUE;
1817         case DID_TRANSPORT_DISRUPTED:
1818                 /*
1819                  * LLD/transport was disrupted during processing of the IO.
1820                  * The transport class is now blocked/blocking,
1821                  * and the transport will decide what to do with the IO
1822                  * based on its timers and recovery capablilities if
1823                  * there are enough retries.
1824                  */
1825                 goto maybe_retry;
1826         case DID_TRANSPORT_FAILFAST:
1827                 /*
1828                  * The transport decided to failfast the IO (most likely
1829                  * the fast io fail tmo fired), so send IO directly upwards.
1830                  */
1831                 return SUCCESS;
1832         case DID_ERROR:
1833                 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1834                     status_byte(scmd->result) == RESERVATION_CONFLICT)
1835                         /*
1836                          * execute reservation conflict processing code
1837                          * lower down
1838                          */
1839                         break;
1840                 /* fallthrough */
1841         case DID_BUS_BUSY:
1842         case DID_PARITY:
1843                 goto maybe_retry;
1844         case DID_TIME_OUT:
1845                 /*
1846                  * when we scan the bus, we get timeout messages for
1847                  * these commands if there is no device available.
1848                  * other hosts report did_no_connect for the same thing.
1849                  */
1850                 if ((scmd->cmnd[0] == TEST_UNIT_READY ||
1851                      scmd->cmnd[0] == INQUIRY)) {
1852                         return SUCCESS;
1853                 } else {
1854                         return FAILED;
1855                 }
1856         case DID_RESET:
1857                 return SUCCESS;
1858         default:
1859                 return FAILED;
1860         }
1861
1862         /*
1863          * next, check the message byte.
1864          */
1865         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
1866                 return FAILED;
1867
1868         /*
1869          * check the status byte to see if this indicates anything special.
1870          */
1871         switch (status_byte(scmd->result)) {
1872         case QUEUE_FULL:
1873                 scsi_handle_queue_full(scmd->device);
1874                 /*
1875                  * the case of trying to send too many commands to a
1876                  * tagged queueing device.
1877                  */
1878         case BUSY:
1879                 /*
1880                  * device can't talk to us at the moment.  Should only
1881                  * occur (SAM-3) when the task queue is empty, so will cause
1882                  * the empty queue handling to trigger a stall in the
1883                  * device.
1884                  */
1885                 return ADD_TO_MLQUEUE;
1886         case GOOD:
1887                 if (scmd->cmnd[0] == REPORT_LUNS)
1888                         scmd->device->sdev_target->expecting_lun_change = 0;
1889                 scsi_handle_queue_ramp_up(scmd->device);
1890         case COMMAND_TERMINATED:
1891                 return SUCCESS;
1892         case TASK_ABORTED:
1893                 goto maybe_retry;
1894         case CHECK_CONDITION:
1895                 rtn = scsi_check_sense(scmd);
1896                 if (rtn == NEEDS_RETRY)
1897                         goto maybe_retry;
1898                 /* if rtn == FAILED, we have no sense information;
1899                  * returning FAILED will wake the error handler thread
1900                  * to collect the sense and redo the decide
1901                  * disposition */
1902                 return rtn;
1903         case CONDITION_GOOD:
1904         case INTERMEDIATE_GOOD:
1905         case INTERMEDIATE_C_GOOD:
1906         case ACA_ACTIVE:
1907                 /*
1908                  * who knows?  FIXME(eric)
1909                  */
1910                 return SUCCESS;
1911
1912         case RESERVATION_CONFLICT:
1913                 sdev_printk(KERN_INFO, scmd->device,
1914                             "reservation conflict\n");
1915                 set_host_byte(scmd, DID_NEXUS_FAILURE);
1916                 return SUCCESS; /* causes immediate i/o error */
1917         default:
1918                 return FAILED;
1919         }
1920         return FAILED;
1921
1922       maybe_retry:
1923
1924         /* we requeue for retry because the error was retryable, and
1925          * the request was not marked fast fail.  Note that above,
1926          * even if the request is marked fast fail, we still requeue
1927          * for queue congestion conditions (QUEUE_FULL or BUSY) */
1928         if ((++scmd->retries) <= scmd->allowed
1929             && !scsi_noretry_cmd(scmd)) {
1930                 return NEEDS_RETRY;
1931         } else {
1932                 /*
1933                  * no more retries - report this one back to upper level.
1934                  */
1935                 return SUCCESS;
1936         }
1937 }
1938
1939 static void eh_lock_door_done(struct request *req, int uptodate)
1940 {
1941         __blk_put_request(req->q, req);
1942 }
1943
1944 /**
1945  * scsi_eh_lock_door - Prevent medium removal for the specified device
1946  * @sdev:       SCSI device to prevent medium removal
1947  *
1948  * Locking:
1949  *      We must be called from process context.
1950  *
1951  * Notes:
1952  *      We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
1953  *      head of the devices request queue, and continue.
1954  */
1955 static void scsi_eh_lock_door(struct scsi_device *sdev)
1956 {
1957         struct request *req;
1958
1959         /*
1960          * blk_get_request with GFP_KERNEL (__GFP_WAIT) sleeps until a
1961          * request becomes available
1962          */
1963         req = blk_get_request(sdev->request_queue, READ, GFP_KERNEL);
1964         if (IS_ERR(req))
1965                 return;
1966
1967         blk_rq_set_block_pc(req);
1968
1969         req->cmd[0] = ALLOW_MEDIUM_REMOVAL;
1970         req->cmd[1] = 0;
1971         req->cmd[2] = 0;
1972         req->cmd[3] = 0;
1973         req->cmd[4] = SCSI_REMOVAL_PREVENT;
1974         req->cmd[5] = 0;
1975
1976         req->cmd_len = COMMAND_SIZE(req->cmd[0]);
1977
1978         req->cmd_flags |= REQ_QUIET;
1979         req->timeout = 10 * HZ;
1980         req->retries = 5;
1981
1982         blk_execute_rq_nowait(req->q, NULL, req, 1, eh_lock_door_done);
1983 }
1984
1985 /**
1986  * scsi_restart_operations - restart io operations to the specified host.
1987  * @shost:      Host we are restarting.
1988  *
1989  * Notes:
1990  *    When we entered the error handler, we blocked all further i/o to
1991  *    this device.  we need to 'reverse' this process.
1992  */
1993 static void scsi_restart_operations(struct Scsi_Host *shost)
1994 {
1995         struct scsi_device *sdev;
1996         unsigned long flags;
1997
1998         /*
1999          * If the door was locked, we need to insert a door lock request
2000          * onto the head of the SCSI request queue for the device.  There
2001          * is no point trying to lock the door of an off-line device.
2002          */
2003         shost_for_each_device(sdev, shost) {
2004                 if (scsi_device_online(sdev) && sdev->locked)
2005                         scsi_eh_lock_door(sdev);
2006         }
2007
2008         /*
2009          * next free up anything directly waiting upon the host.  this
2010          * will be requests for character device operations, and also for
2011          * ioctls to queued block devices.
2012          */
2013         SCSI_LOG_ERROR_RECOVERY(3,
2014                 shost_printk(KERN_INFO, shost, "waking up host to restart\n"));
2015
2016         spin_lock_irqsave(shost->host_lock, flags);
2017         if (scsi_host_set_state(shost, SHOST_RUNNING))
2018                 if (scsi_host_set_state(shost, SHOST_CANCEL))
2019                         BUG_ON(scsi_host_set_state(shost, SHOST_DEL));
2020         spin_unlock_irqrestore(shost->host_lock, flags);
2021
2022         wake_up(&shost->host_wait);
2023
2024         /*
2025          * finally we need to re-initiate requests that may be pending.  we will
2026          * have had everything blocked while error handling is taking place, and
2027          * now that error recovery is done, we will need to ensure that these
2028          * requests are started.
2029          */
2030         scsi_run_host_queues(shost);
2031
2032         /*
2033          * if eh is active and host_eh_scheduled is pending we need to re-run
2034          * recovery.  we do this check after scsi_run_host_queues() to allow
2035          * everything pent up since the last eh run a chance to make forward
2036          * progress before we sync again.  Either we'll immediately re-run
2037          * recovery or scsi_device_unbusy() will wake us again when these
2038          * pending commands complete.
2039          */
2040         spin_lock_irqsave(shost->host_lock, flags);
2041         if (shost->host_eh_scheduled)
2042                 if (scsi_host_set_state(shost, SHOST_RECOVERY))
2043                         WARN_ON(scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY));
2044         spin_unlock_irqrestore(shost->host_lock, flags);
2045 }
2046
2047 /**
2048  * scsi_eh_ready_devs - check device ready state and recover if not.
2049  * @shost:      host to be recovered.
2050  * @work_q:     &list_head for pending commands.
2051  * @done_q:     &list_head for processed commands.
2052  */
2053 void scsi_eh_ready_devs(struct Scsi_Host *shost,
2054                         struct list_head *work_q,
2055                         struct list_head *done_q)
2056 {
2057         if (!scsi_eh_stu(shost, work_q, done_q))
2058                 if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
2059                         if (!scsi_eh_target_reset(shost, work_q, done_q))
2060                                 if (!scsi_eh_bus_reset(shost, work_q, done_q))
2061                                         if (!scsi_eh_host_reset(shost, work_q, done_q))
2062                                                 scsi_eh_offline_sdevs(work_q,
2063                                                                       done_q);
2064 }
2065 EXPORT_SYMBOL_GPL(scsi_eh_ready_devs);
2066
2067 /**
2068  * scsi_eh_flush_done_q - finish processed commands or retry them.
2069  * @done_q:     list_head of processed commands.
2070  */
2071 void scsi_eh_flush_done_q(struct list_head *done_q)
2072 {
2073         struct scsi_cmnd *scmd, *next;
2074
2075         list_for_each_entry_safe(scmd, next, done_q, eh_entry) {
2076                 list_del_init(&scmd->eh_entry);
2077                 if (scsi_device_online(scmd->device) &&
2078                     !scsi_noretry_cmd(scmd) &&
2079                     (++scmd->retries <= scmd->allowed)) {
2080                         SCSI_LOG_ERROR_RECOVERY(3,
2081                                 scmd_printk(KERN_INFO, scmd,
2082                                              "%s: flush retry cmd: %p\n",
2083                                              current->comm, scmd));
2084                                 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
2085                 } else {
2086                         /*
2087                          * If just we got sense for the device (called
2088                          * scsi_eh_get_sense), scmd->result is already
2089                          * set, do not set DRIVER_TIMEOUT.
2090                          */
2091                         if (!scmd->result)
2092                                 scmd->result |= (DRIVER_TIMEOUT << 24);
2093                         SCSI_LOG_ERROR_RECOVERY(3,
2094                                 scmd_printk(KERN_INFO, scmd,
2095                                              "%s: flush finish cmd: %p\n",
2096                                              current->comm, scmd));
2097                         scsi_finish_command(scmd);
2098                 }
2099         }
2100 }
2101 EXPORT_SYMBOL(scsi_eh_flush_done_q);
2102
2103 /**
2104  * scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
2105  * @shost:      Host to unjam.
2106  *
2107  * Notes:
2108  *    When we come in here, we *know* that all commands on the bus have
2109  *    either completed, failed or timed out.  we also know that no further
2110  *    commands are being sent to the host, so things are relatively quiet
2111  *    and we have freedom to fiddle with things as we wish.
2112  *
2113  *    This is only the *default* implementation.  it is possible for
2114  *    individual drivers to supply their own version of this function, and
2115  *    if the maintainer wishes to do this, it is strongly suggested that
2116  *    this function be taken as a template and modified.  this function
2117  *    was designed to correctly handle problems for about 95% of the
2118  *    different cases out there, and it should always provide at least a
2119  *    reasonable amount of error recovery.
2120  *
2121  *    Any command marked 'failed' or 'timeout' must eventually have
2122  *    scsi_finish_cmd() called for it.  we do all of the retry stuff
2123  *    here, so when we restart the host after we return it should have an
2124  *    empty queue.
2125  */
2126 static void scsi_unjam_host(struct Scsi_Host *shost)
2127 {
2128         unsigned long flags;
2129         LIST_HEAD(eh_work_q);
2130         LIST_HEAD(eh_done_q);
2131
2132         spin_lock_irqsave(shost->host_lock, flags);
2133         list_splice_init(&shost->eh_cmd_q, &eh_work_q);
2134         spin_unlock_irqrestore(shost->host_lock, flags);
2135
2136         SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
2137
2138         if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
2139                 if (!scsi_eh_abort_cmds(&eh_work_q, &eh_done_q))
2140                         scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
2141
2142         spin_lock_irqsave(shost->host_lock, flags);
2143         if (shost->eh_deadline != -1)
2144                 shost->last_reset = 0;
2145         spin_unlock_irqrestore(shost->host_lock, flags);
2146         scsi_eh_flush_done_q(&eh_done_q);
2147 }
2148
2149 /**
2150  * scsi_error_handler - SCSI error handler thread
2151  * @data:       Host for which we are running.
2152  *
2153  * Notes:
2154  *    This is the main error handling loop.  This is run as a kernel thread
2155  *    for every SCSI host and handles all error handling activity.
2156  */
2157 int scsi_error_handler(void *data)
2158 {
2159         struct Scsi_Host *shost = data;
2160
2161         /*
2162          * We use TASK_INTERRUPTIBLE so that the thread is not
2163          * counted against the load average as a running process.
2164          * We never actually get interrupted because kthread_run
2165          * disables signal delivery for the created thread.
2166          */
2167         while (!kthread_should_stop()) {
2168                 set_current_state(TASK_INTERRUPTIBLE);
2169                 if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||
2170                     shost->host_failed != atomic_read(&shost->host_busy)) {
2171                         SCSI_LOG_ERROR_RECOVERY(1,
2172                                 shost_printk(KERN_INFO, shost,
2173                                              "scsi_eh_%d: sleeping\n",
2174                                              shost->host_no));
2175                         schedule();
2176                         continue;
2177                 }
2178
2179                 __set_current_state(TASK_RUNNING);
2180                 SCSI_LOG_ERROR_RECOVERY(1,
2181                         shost_printk(KERN_INFO, shost,
2182                                      "scsi_eh_%d: waking up %d/%d/%d\n",
2183                                      shost->host_no, shost->host_eh_scheduled,
2184                                      shost->host_failed,
2185                                      atomic_read(&shost->host_busy)));
2186
2187                 /*
2188                  * We have a host that is failing for some reason.  Figure out
2189                  * what we need to do to get it up and online again (if we can).
2190                  * If we fail, we end up taking the thing offline.
2191                  */
2192                 if (!shost->eh_noresume && scsi_autopm_get_host(shost) != 0) {
2193                         SCSI_LOG_ERROR_RECOVERY(1,
2194                                 printk(KERN_ERR "Error handler scsi_eh_%d "
2195                                                 "unable to autoresume\n",
2196                                                 shost->host_no));
2197                         continue;
2198                 }
2199
2200                 if (shost->transportt->eh_strategy_handler)
2201                         shost->transportt->eh_strategy_handler(shost);
2202                 else
2203                         scsi_unjam_host(shost);
2204
2205                 /*
2206                  * Note - if the above fails completely, the action is to take
2207                  * individual devices offline and flush the queue of any
2208                  * outstanding requests that may have been pending.  When we
2209                  * restart, we restart any I/O to any other devices on the bus
2210                  * which are still online.
2211                  */
2212                 scsi_restart_operations(shost);
2213                 if (!shost->eh_noresume)
2214                         scsi_autopm_put_host(shost);
2215         }
2216         __set_current_state(TASK_RUNNING);
2217
2218         SCSI_LOG_ERROR_RECOVERY(1,
2219                 shost_printk(KERN_INFO, shost,
2220                              "Error handler scsi_eh_%d exiting\n",
2221                              shost->host_no));
2222         shost->ehandler = NULL;
2223         return 0;
2224 }
2225
2226 /*
2227  * Function:    scsi_report_bus_reset()
2228  *
2229  * Purpose:     Utility function used by low-level drivers to report that
2230  *              they have observed a bus reset on the bus being handled.
2231  *
2232  * Arguments:   shost       - Host in question
2233  *              channel     - channel on which reset was observed.
2234  *
2235  * Returns:     Nothing
2236  *
2237  * Lock status: Host lock must be held.
2238  *
2239  * Notes:       This only needs to be called if the reset is one which
2240  *              originates from an unknown location.  Resets originated
2241  *              by the mid-level itself don't need to call this, but there
2242  *              should be no harm.
2243  *
2244  *              The main purpose of this is to make sure that a CHECK_CONDITION
2245  *              is properly treated.
2246  */
2247 void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
2248 {
2249         struct scsi_device *sdev;
2250
2251         __shost_for_each_device(sdev, shost) {
2252                 if (channel == sdev_channel(sdev))
2253                         __scsi_report_device_reset(sdev, NULL);
2254         }
2255 }
2256 EXPORT_SYMBOL(scsi_report_bus_reset);
2257
2258 /*
2259  * Function:    scsi_report_device_reset()
2260  *
2261  * Purpose:     Utility function used by low-level drivers to report that
2262  *              they have observed a device reset on the device being handled.
2263  *
2264  * Arguments:   shost       - Host in question
2265  *              channel     - channel on which reset was observed
2266  *              target      - target on which reset was observed
2267  *
2268  * Returns:     Nothing
2269  *
2270  * Lock status: Host lock must be held
2271  *
2272  * Notes:       This only needs to be called if the reset is one which
2273  *              originates from an unknown location.  Resets originated
2274  *              by the mid-level itself don't need to call this, but there
2275  *              should be no harm.
2276  *
2277  *              The main purpose of this is to make sure that a CHECK_CONDITION
2278  *              is properly treated.
2279  */
2280 void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
2281 {
2282         struct scsi_device *sdev;
2283
2284         __shost_for_each_device(sdev, shost) {
2285                 if (channel == sdev_channel(sdev) &&
2286                     target == sdev_id(sdev))
2287                         __scsi_report_device_reset(sdev, NULL);
2288         }
2289 }
2290 EXPORT_SYMBOL(scsi_report_device_reset);
2291
2292 static void
2293 scsi_reset_provider_done_command(struct scsi_cmnd *scmd)
2294 {
2295 }
2296
2297 /*
2298  * Function:    scsi_reset_provider
2299  *
2300  * Purpose:     Send requested reset to a bus or device at any phase.
2301  *
2302  * Arguments:   device  - device to send reset to
2303  *              flag - reset type (see scsi.h)
2304  *
2305  * Returns:     SUCCESS/FAILURE.
2306  *
2307  * Notes:       This is used by the SCSI Generic driver to provide
2308  *              Bus/Device reset capability.
2309  */
2310 int
2311 scsi_reset_provider(struct scsi_device *dev, int flag)
2312 {
2313         struct scsi_cmnd *scmd;
2314         struct Scsi_Host *shost = dev->host;
2315         struct request req;
2316         unsigned long flags;
2317         int rtn;
2318
2319         if (scsi_autopm_get_host(shost) < 0)
2320                 return FAILED;
2321
2322         if (!get_device(&dev->sdev_gendev)) {
2323                 rtn = FAILED;
2324                 goto out_put_autopm_host;
2325         }
2326
2327         scmd = scsi_get_command(dev, GFP_KERNEL);
2328         if (!scmd) {
2329                 rtn = FAILED;
2330                 put_device(&dev->sdev_gendev);
2331                 goto out_put_autopm_host;
2332         }
2333
2334         blk_rq_init(NULL, &req);
2335         scmd->request = &req;
2336
2337         scmd->cmnd = req.cmd;
2338
2339         scmd->scsi_done         = scsi_reset_provider_done_command;
2340         memset(&scmd->sdb, 0, sizeof(scmd->sdb));
2341
2342         scmd->cmd_len                   = 0;
2343
2344         scmd->sc_data_direction         = DMA_BIDIRECTIONAL;
2345
2346         spin_lock_irqsave(shost->host_lock, flags);
2347         shost->tmf_in_progress = 1;
2348         spin_unlock_irqrestore(shost->host_lock, flags);
2349
2350         switch (flag) {
2351         case SCSI_TRY_RESET_DEVICE:
2352                 rtn = scsi_try_bus_device_reset(scmd);
2353                 if (rtn == SUCCESS)
2354                         break;
2355                 /* FALLTHROUGH */
2356         case SCSI_TRY_RESET_TARGET:
2357                 rtn = scsi_try_target_reset(scmd);
2358                 if (rtn == SUCCESS)
2359                         break;
2360                 /* FALLTHROUGH */
2361         case SCSI_TRY_RESET_BUS:
2362                 rtn = scsi_try_bus_reset(scmd);
2363                 if (rtn == SUCCESS)
2364                         break;
2365                 /* FALLTHROUGH */
2366         case SCSI_TRY_RESET_HOST:
2367                 rtn = scsi_try_host_reset(scmd);
2368                 break;
2369         default:
2370                 rtn = FAILED;
2371         }
2372
2373         spin_lock_irqsave(shost->host_lock, flags);
2374         shost->tmf_in_progress = 0;
2375         spin_unlock_irqrestore(shost->host_lock, flags);
2376
2377         /*
2378          * be sure to wake up anyone who was sleeping or had their queue
2379          * suspended while we performed the TMF.
2380          */
2381         SCSI_LOG_ERROR_RECOVERY(3,
2382                 shost_printk(KERN_INFO, shost,
2383                              "waking up host to restart after TMF\n"));
2384
2385         wake_up(&shost->host_wait);
2386
2387         scsi_run_host_queues(shost);
2388
2389         scsi_next_command(scmd);
2390 out_put_autopm_host:
2391         scsi_autopm_put_host(shost);
2392         return rtn;
2393 }
2394 EXPORT_SYMBOL(scsi_reset_provider);
2395
2396 /**
2397  * scsi_normalize_sense - normalize main elements from either fixed or
2398  *                      descriptor sense data format into a common format.
2399  *
2400  * @sense_buffer:       byte array containing sense data returned by device
2401  * @sb_len:             number of valid bytes in sense_buffer
2402  * @sshdr:              pointer to instance of structure that common
2403  *                      elements are written to.
2404  *
2405  * Notes:
2406  *      The "main elements" from sense data are: response_code, sense_key,
2407  *      asc, ascq and additional_length (only for descriptor format).
2408  *
2409  *      Typically this function can be called after a device has
2410  *      responded to a SCSI command with the CHECK_CONDITION status.
2411  *
2412  * Return value:
2413  *      1 if valid sense data information found, else 0;
2414  */
2415 int scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
2416                          struct scsi_sense_hdr *sshdr)
2417 {
2418         if (!sense_buffer || !sb_len)
2419                 return 0;
2420
2421         memset(sshdr, 0, sizeof(struct scsi_sense_hdr));
2422
2423         sshdr->response_code = (sense_buffer[0] & 0x7f);
2424
2425         if (!scsi_sense_valid(sshdr))
2426                 return 0;
2427
2428         if (sshdr->response_code >= 0x72) {
2429                 /*
2430                  * descriptor format
2431                  */
2432                 if (sb_len > 1)
2433                         sshdr->sense_key = (sense_buffer[1] & 0xf);
2434                 if (sb_len > 2)
2435                         sshdr->asc = sense_buffer[2];
2436                 if (sb_len > 3)
2437                         sshdr->ascq = sense_buffer[3];
2438                 if (sb_len > 7)
2439                         sshdr->additional_length = sense_buffer[7];
2440         } else {
2441                 /*
2442                  * fixed format
2443                  */
2444                 if (sb_len > 2)
2445                         sshdr->sense_key = (sense_buffer[2] & 0xf);
2446                 if (sb_len > 7) {
2447                         sb_len = (sb_len < (sense_buffer[7] + 8)) ?
2448                                          sb_len : (sense_buffer[7] + 8);
2449                         if (sb_len > 12)
2450                                 sshdr->asc = sense_buffer[12];
2451                         if (sb_len > 13)
2452                                 sshdr->ascq = sense_buffer[13];
2453                 }
2454         }
2455
2456         return 1;
2457 }
2458 EXPORT_SYMBOL(scsi_normalize_sense);
2459
2460 int scsi_command_normalize_sense(struct scsi_cmnd *cmd,
2461                                  struct scsi_sense_hdr *sshdr)
2462 {
2463         return scsi_normalize_sense(cmd->sense_buffer,
2464                         SCSI_SENSE_BUFFERSIZE, sshdr);
2465 }
2466 EXPORT_SYMBOL(scsi_command_normalize_sense);
2467
2468 /**
2469  * scsi_sense_desc_find - search for a given descriptor type in descriptor sense data format.
2470  * @sense_buffer:       byte array of descriptor format sense data
2471  * @sb_len:             number of valid bytes in sense_buffer
2472  * @desc_type:          value of descriptor type to find
2473  *                      (e.g. 0 -> information)
2474  *
2475  * Notes:
2476  *      only valid when sense data is in descriptor format
2477  *
2478  * Return value:
2479  *      pointer to start of (first) descriptor if found else NULL
2480  */
2481 const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len,
2482                                 int desc_type)
2483 {
2484         int add_sen_len, add_len, desc_len, k;
2485         const u8 * descp;
2486
2487         if ((sb_len < 8) || (0 == (add_sen_len = sense_buffer[7])))
2488                 return NULL;
2489         if ((sense_buffer[0] < 0x72) || (sense_buffer[0] > 0x73))
2490                 return NULL;
2491         add_sen_len = (add_sen_len < (sb_len - 8)) ?
2492                         add_sen_len : (sb_len - 8);
2493         descp = &sense_buffer[8];
2494         for (desc_len = 0, k = 0; k < add_sen_len; k += desc_len) {
2495                 descp += desc_len;
2496                 add_len = (k < (add_sen_len - 1)) ? descp[1]: -1;
2497                 desc_len = add_len + 2;
2498                 if (descp[0] == desc_type)
2499                         return descp;
2500                 if (add_len < 0) // short descriptor ??
2501                         break;
2502         }
2503         return NULL;
2504 }
2505 EXPORT_SYMBOL(scsi_sense_desc_find);
2506
2507 /**
2508  * scsi_get_sense_info_fld - get information field from sense data (either fixed or descriptor format)
2509  * @sense_buffer:       byte array of sense data
2510  * @sb_len:             number of valid bytes in sense_buffer
2511  * @info_out:           pointer to 64 integer where 8 or 4 byte information
2512  *                      field will be placed if found.
2513  *
2514  * Return value:
2515  *      1 if information field found, 0 if not found.
2516  */
2517 int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
2518                             u64 * info_out)
2519 {
2520         int j;
2521         const u8 * ucp;
2522         u64 ull;
2523
2524         if (sb_len < 7)
2525                 return 0;
2526         switch (sense_buffer[0] & 0x7f) {
2527         case 0x70:
2528         case 0x71:
2529                 if (sense_buffer[0] & 0x80) {
2530                         *info_out = (sense_buffer[3] << 24) +
2531                                     (sense_buffer[4] << 16) +
2532                                     (sense_buffer[5] << 8) + sense_buffer[6];
2533                         return 1;
2534                 } else
2535                         return 0;
2536         case 0x72:
2537         case 0x73:
2538                 ucp = scsi_sense_desc_find(sense_buffer, sb_len,
2539                                            0 /* info desc */);
2540                 if (ucp && (0xa == ucp[1])) {
2541                         ull = 0;
2542                         for (j = 0; j < 8; ++j) {
2543                                 if (j > 0)
2544                                         ull <<= 8;
2545                                 ull |= ucp[4 + j];
2546                         }
2547                         *info_out = ull;
2548                         return 1;
2549                 } else
2550                         return 0;
2551         default:
2552                 return 0;
2553         }
2554 }
2555 EXPORT_SYMBOL(scsi_get_sense_info_fld);
2556
2557 /**
2558  * scsi_build_sense_buffer - build sense data in a buffer
2559  * @desc:       Sense format (non zero == descriptor format,
2560  *              0 == fixed format)
2561  * @buf:        Where to build sense data
2562  * @key:        Sense key
2563  * @asc:        Additional sense code
2564  * @ascq:       Additional sense code qualifier
2565  *
2566  **/
2567 void scsi_build_sense_buffer(int desc, u8 *buf, u8 key, u8 asc, u8 ascq)
2568 {
2569         if (desc) {
2570                 buf[0] = 0x72;  /* descriptor, current */
2571                 buf[1] = key;
2572                 buf[2] = asc;
2573                 buf[3] = ascq;
2574                 buf[7] = 0;
2575         } else {
2576                 buf[0] = 0x70;  /* fixed, current */
2577                 buf[2] = key;
2578                 buf[7] = 0xa;
2579                 buf[12] = asc;
2580                 buf[13] = ascq;
2581         }
2582 }
2583 EXPORT_SYMBOL(scsi_build_sense_buffer);