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