Pileus Git - ~andy/linux/blob - 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/timer.h>
  20 #include <linux/string.h>
  21 #include <linux/kernel.h>
  22 #include <linux/freezer.h>
  23 #include <linux/kthread.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/blkdev.h>
  26 #include <linux/delay.h>
  27
  28 #include <scsi/scsi.h>
  29 #include <scsi/scsi_cmnd.h>
  30 #include <scsi/scsi_dbg.h>
  31 #include <scsi/scsi_device.h>
  32 #include <scsi/scsi_eh.h>
  33 #include <scsi/scsi_transport.h>
  34 #include <scsi/scsi_host.h>
  35 #include <scsi/scsi_ioctl.h>
  36
  37 #include "scsi_priv.h"
  38 #include "scsi_logging.h"
  39 #include "scsi_transport_api.h"
  40
  41 #define SENSE_TIMEOUT           (10*HZ)
  42
  43 /*
  44  * These should *probably* be handled by the host itself.
  45  * Since it is allowed to sleep, it probably should.
  46  */
  47 #define BUS_RESET_SETTLE_TIME   (10)
  48 #define HOST_RESET_SETTLE_TIME  (10)
  49
  50 /* called with shost->host_lock held */
  51 void scsi_eh_wakeup(struct Scsi_Host *shost)
  52 {
  53         if (shost->host_busy == shost->host_failed) {
  54                 wake_up_process(shost->ehandler);
  55                 SCSI_LOG_ERROR_RECOVERY(5,
  56                                 printk("Waking error handler thread\n"));
  57         }
  58 }
  59
  60 /**
  61  * scsi_schedule_eh - schedule EH for SCSI host
  62  * @shost:      SCSI host to invoke error handling on.
  63  *
  64  * Schedule SCSI EH without scmd.
  65  */
  66 void scsi_schedule_eh(struct Scsi_Host *shost)
  67 {
  68         unsigned long flags;
  69
  70         spin_lock_irqsave(shost->host_lock, flags);
  71
  72         if (scsi_host_set_state(shost, SHOST_RECOVERY) == 0 ||
  73             scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY) == 0) {
  74                 shost->host_eh_scheduled++;
  75                 scsi_eh_wakeup(shost);
  76         }
  77
  78         spin_unlock_irqrestore(shost->host_lock, flags);
  79 }
  80 EXPORT_SYMBOL_GPL(scsi_schedule_eh);
  81
  82 /**
  83  * scsi_eh_scmd_add - add scsi cmd to error handling.
  84  * @scmd:       scmd to run eh on.
  85  * @eh_flag:    optional SCSI_EH flag.
  86  *
  87  * Return value:
  88  *      0 on failure.
  89  */
  90 int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
  91 {
  92         struct Scsi_Host *shost = scmd->device->host;
  93         unsigned long flags;
  94         int ret = 0;
  95
  96         if (!shost->ehandler)
  97                 return 0;
  98
  99         spin_lock_irqsave(shost->host_lock, flags);
 100         if (scsi_host_set_state(shost, SHOST_RECOVERY))
 101                 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY))
 102                         goto out_unlock;
 103
 104         ret = 1;
 105         scmd->eh_eflags |= eh_flag;
 106         list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
 107         shost->host_failed++;
 108         scsi_eh_wakeup(shost);
 109  out_unlock:
 110         spin_unlock_irqrestore(shost->host_lock, flags);
 111         return ret;
 112 }
 113
 114 /**
 115  * scsi_times_out - Timeout function for normal scsi commands.
 116  * @req:        request that is timing out.
 117  *
 118  * Notes:
 119  *     We do not need to lock this.  There is the potential for a race
 120  *     only in that the normal completion handling might run, but if the
 121  *     normal completion function determines that the timer has already
 122  *     fired, then it mustn't do anything.
 123  */
 124 enum blk_eh_timer_return scsi_times_out(struct request *req)
 125 {
 126         struct scsi_cmnd *scmd = req->special;
 127         enum blk_eh_timer_return rtn = BLK_EH_NOT_HANDLED;
 128
 129         scsi_log_completion(scmd, TIMEOUT_ERROR);
 130
 131         if (scmd->device->host->transportt->eh_timed_out)
 132                 rtn = scmd->device->host->transportt->eh_timed_out(scmd);
 133         else if (scmd->device->host->hostt->eh_timed_out)
 134                 rtn = scmd->device->host->hostt->eh_timed_out(scmd);
 135
 136         if (unlikely(rtn == BLK_EH_NOT_HANDLED &&
 137                      !scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD))) {
 138                 scmd->result |= DID_TIME_OUT << 16;
 139                 rtn = BLK_EH_HANDLED;
 140         }
 141
 142         return rtn;
 143 }
 144
 145 /**
 146  * scsi_block_when_processing_errors - Prevent cmds from being queued.
 147  * @sdev:       Device on which we are performing recovery.
 148  *
 149  * Description:
 150  *     We block until the host is out of error recovery, and then check to
 151  *     see whether the host or the device is offline.
 152  *
 153  * Return value:
 154  *     0 when dev was taken offline by error recovery. 1 OK to proceed.
 155  */
 156 int scsi_block_when_processing_errors(struct scsi_device *sdev)
 157 {
 158         int online;
 159
 160         wait_event(sdev->host->host_wait, !scsi_host_in_recovery(sdev->host));
 161
 162         online = scsi_device_online(sdev);
 163
 164         SCSI_LOG_ERROR_RECOVERY(5, printk("%s: rtn: %d\n", __func__,
 165                                           online));
 166
 167         return online;
 168 }
 169 EXPORT_SYMBOL(scsi_block_when_processing_errors);
 170
 171 #ifdef CONFIG_SCSI_LOGGING
 172 /**
 173  * scsi_eh_prt_fail_stats - Log info on failures.
 174  * @shost:      scsi host being recovered.
 175  * @work_q:     Queue of scsi cmds to process.
 176  */
 177 static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
 178                                           struct list_head *work_q)
 179 {
 180         struct scsi_cmnd *scmd;
 181         struct scsi_device *sdev;
 182         int total_failures = 0;
 183         int cmd_failed = 0;
 184         int cmd_cancel = 0;
 185         int devices_failed = 0;
 186
 187         shost_for_each_device(sdev, shost) {
 188                 list_for_each_entry(scmd, work_q, eh_entry) {
 189                         if (scmd->device == sdev) {
 190                                 ++total_failures;
 191                                 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD)
 192                                         ++cmd_cancel;
 193                                 else
 194                                         ++cmd_failed;
 195                         }
 196                 }
 197
 198                 if (cmd_cancel || cmd_failed) {
 199                         SCSI_LOG_ERROR_RECOVERY(3,
 200                                 sdev_printk(KERN_INFO, sdev,
 201                                             "%s: cmds failed: %d, cancel: %d\n",
 202                                             __func__, cmd_failed,
 203                                             cmd_cancel));
 204                         cmd_cancel = 0;
 205                         cmd_failed = 0;
 206                         ++devices_failed;
 207                 }
 208         }
 209
 210         SCSI_LOG_ERROR_RECOVERY(2, printk("Total of %d commands on %d"
 211                                           " devices require eh work\n",
 212                                   total_failures, devices_failed));
 213 }
 214 #endif
 215
 216 /**
 217  * scsi_check_sense - Examine scsi cmd sense
 218  * @scmd:       Cmd to have sense checked.
 219  *
 220  * Return value:
 221  *      SUCCESS or FAILED or NEEDS_RETRY
 222  *
 223  * Notes:
 224  *      When a deferred error is detected the current command has
 225  *      not been executed and needs retrying.
 226  */
 227 static int scsi_check_sense(struct scsi_cmnd *scmd)
 228 {
 229         struct scsi_device *sdev = scmd->device;
 230         struct scsi_sense_hdr sshdr;
 231
 232         if (! scsi_command_normalize_sense(scmd, &sshdr))
 233                 return FAILED;  /* no valid sense data */
 234
 235         if (scsi_sense_is_deferred(&sshdr))
 236                 return NEEDS_RETRY;
 237
 238         if (sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh &&
 239                         sdev->scsi_dh_data->scsi_dh->check_sense) {
 240                 int rc;
 241
 242                 rc = sdev->scsi_dh_data->scsi_dh->check_sense(sdev, &sshdr);
 243                 if (rc != SCSI_RETURN_NOT_HANDLED)
 244                         return rc;
 245                 /* handler does not care. Drop down to default handling */
 246         }
 247
 248         /*
 249          * Previous logic looked for FILEMARK, EOM or ILI which are
 250          * mainly associated with tapes and returned SUCCESS.
 251          */
 252         if (sshdr.response_code == 0x70) {
 253                 /* fixed format */
 254                 if (scmd->sense_buffer[2] & 0xe0)
 255                         return SUCCESS;
 256         } else {
 257                 /*
 258                  * descriptor format: look for "stream commands sense data
 259                  * descriptor" (see SSC-3). Assume single sense data
 260                  * descriptor. Ignore ILI from SBC-2 READ LONG and WRITE LONG.
 261                  */
 262                 if ((sshdr.additional_length > 3) &&
 263                     (scmd->sense_buffer[8] == 0x4) &&
 264                     (scmd->sense_buffer[11] & 0xe0))
 265                         return SUCCESS;
 266         }
 267
 268         switch (sshdr.sense_key) {
 269         case NO_SENSE:
 270                 return SUCCESS;
 271         case RECOVERED_ERROR:
 272                 return /* soft_error */ SUCCESS;
 273
 274         case ABORTED_COMMAND:
 275                 if (sshdr.asc == 0x10) /* DIF */
 276                         return SUCCESS;
 277
 278                 return NEEDS_RETRY;
 279         case NOT_READY:
 280         case UNIT_ATTENTION:
 281                 /*
 282                  * if we are expecting a cc/ua because of a bus reset that we
 283                  * performed, treat this just as a retry.  otherwise this is
 284                  * information that we should pass up to the upper-level driver
 285                  * so that we can deal with it there.
 286                  */
 287                 if (scmd->device->expecting_cc_ua) {
 288                         scmd->device->expecting_cc_ua = 0;
 289                         return NEEDS_RETRY;
 290                 }
 291                 /*
 292                  * if the device is in the process of becoming ready, we
 293                  * should retry.
 294                  */
 295                 if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01))
 296                         return NEEDS_RETRY;
 297                 /*
 298                  * if the device is not started, we need to wake
 299                  * the error handler to start the motor
 300                  */
 301                 if (scmd->device->allow_restart &&
 302                     (sshdr.asc == 0x04) && (sshdr.ascq == 0x02))
 303                         return FAILED;
 304                 return SUCCESS;
 305
 306                 /* these three are not supported */
 307         case COPY_ABORTED:
 308         case VOLUME_OVERFLOW:
 309         case MISCOMPARE:
 310                 return SUCCESS;
 311
 312         case MEDIUM_ERROR:
 313                 if (sshdr.asc == 0x11 || /* UNRECOVERED READ ERR */
 314                     sshdr.asc == 0x13 || /* AMNF DATA FIELD */
 315                     sshdr.asc == 0x14) { /* RECORD NOT FOUND */
 316                         return SUCCESS;
 317                 }
 318                 return NEEDS_RETRY;
 319
 320         case HARDWARE_ERROR:
 321                 if (scmd->device->retry_hwerror)
 322                         return ADD_TO_MLQUEUE;
 323                 else
 324                         return SUCCESS;
 325
 326         case ILLEGAL_REQUEST:
 327         case BLANK_CHECK:
 328         case DATA_PROTECT:
 329         default:
 330                 return SUCCESS;
 331         }
 332 }
 333
 334 static void scsi_handle_queue_full(struct scsi_device *sdev)
 335 {
 336         struct scsi_host_template *sht = sdev->host->hostt;
 337         struct scsi_device *tmp_sdev;
 338
 339         if (!sht->change_queue_depth)
 340                 return;
 341
 342         shost_for_each_device(tmp_sdev, sdev->host) {
 343                 if (tmp_sdev->channel != sdev->channel ||
 344                     tmp_sdev->id != sdev->id)
 345                         continue;
 346                 /*
 347                  * We do not know the number of commands that were at
 348                  * the device when we got the queue full so we start
 349                  * from the highest possible value and work our way down.
 350                  */
 351                 sht->change_queue_depth(tmp_sdev, tmp_sdev->queue_depth - 1,
 352                                         SCSI_QDEPTH_QFULL);
 353         }
 354 }
 355
 356 /**
 357  * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD.
 358  * @scmd:       SCSI cmd to examine.
 359  *
 360  * Notes:
 361  *    This is *only* called when we are examining the status of commands
 362  *    queued during error recovery.  the main difference here is that we
 363  *    don't allow for the possibility of retries here, and we are a lot
 364  *    more restrictive about what we consider acceptable.
 365  */
 366 static int scsi_eh_completed_normally(struct scsi_cmnd *scmd)
 367 {
 368         /*
 369          * first check the host byte, to see if there is anything in there
 370          * that would indicate what we need to do.
 371          */
 372         if (host_byte(scmd->result) == DID_RESET) {
 373                 /*
 374                  * rats.  we are already in the error handler, so we now
 375                  * get to try and figure out what to do next.  if the sense
 376                  * is valid, we have a pretty good idea of what to do.
 377                  * if not, we mark it as FAILED.
 378                  */
 379                 return scsi_check_sense(scmd);
 380         }
 381         if (host_byte(scmd->result) != DID_OK)
 382                 return FAILED;
 383
 384         /*
 385          * next, check the message byte.
 386          */
 387         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
 388                 return FAILED;
 389
 390         /*
 391          * now, check the status byte to see if this indicates
 392          * anything special.
 393          */
 394         switch (status_byte(scmd->result)) {
 395         case GOOD:
 396         case COMMAND_TERMINATED:
 397                 return SUCCESS;
 398         case CHECK_CONDITION:
 399                 return scsi_check_sense(scmd);
 400         case CONDITION_GOOD:
 401         case INTERMEDIATE_GOOD:
 402         case INTERMEDIATE_C_GOOD:
 403                 /*
 404                  * who knows?  FIXME(eric)
 405                  */
 406                 return SUCCESS;
 407         case RESERVATION_CONFLICT:
 408                 /*
 409                  * let issuer deal with this, it could be just fine
 410                  */
 411                 return SUCCESS;
 412         case QUEUE_FULL:
 413                 scsi_handle_queue_full(scmd->device);
 414                 /* fall through */
 415         case BUSY:
 416         default:
 417                 return FAILED;
 418         }
 419         return FAILED;
 420 }
 421
 422 /**
 423  * scsi_eh_done - Completion function for error handling.
 424  * @scmd:       Cmd that is done.
 425  */
 426 static void scsi_eh_done(struct scsi_cmnd *scmd)
 427 {
 428         struct completion     *eh_action;
 429
 430         SCSI_LOG_ERROR_RECOVERY(3,
 431                 printk("%s scmd: %p result: %x\n",
 432                         __func__, scmd, scmd->result));
 433
 434         eh_action = scmd->device->host->eh_action;
 435         if (eh_action)
 436                 complete(eh_action);
 437 }
 438
 439 /**
 440  * scsi_try_host_reset - ask host adapter to reset itself
 441  * @scmd:       SCSI cmd to send hsot reset.
 442  */
 443 static int scsi_try_host_reset(struct scsi_cmnd *scmd)
 444 {
 445         unsigned long flags;
 446         int rtn;
 447
 448         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Host RST\n",
 449                                           __func__));
 450
 451         if (!scmd->device->host->hostt->eh_host_reset_handler)
 452                 return FAILED;
 453
 454         rtn = scmd->device->host->hostt->eh_host_reset_handler(scmd);
 455
 456         if (rtn == SUCCESS) {
 457                 if (!scmd->device->host->hostt->skip_settle_delay)
 458                         ssleep(HOST_RESET_SETTLE_TIME);
 459                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
 460                 scsi_report_bus_reset(scmd->device->host,
 461                                       scmd_channel(scmd));
 462                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
 463         }
 464
 465         return rtn;
 466 }
 467
 468 /**
 469  * scsi_try_bus_reset - ask host to perform a bus reset
 470  * @scmd:       SCSI cmd to send bus reset.
 471  */
 472 static int scsi_try_bus_reset(struct scsi_cmnd *scmd)
 473 {
 474         unsigned long flags;
 475         int rtn;
 476
 477         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Bus RST\n",
 478                                           __func__));
 479
 480         if (!scmd->device->host->hostt->eh_bus_reset_handler)
 481                 return FAILED;
 482
 483         rtn = scmd->device->host->hostt->eh_bus_reset_handler(scmd);
 484
 485         if (rtn == SUCCESS) {
 486                 if (!scmd->device->host->hostt->skip_settle_delay)
 487                         ssleep(BUS_RESET_SETTLE_TIME);
 488                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
 489                 scsi_report_bus_reset(scmd->device->host,
 490                                       scmd_channel(scmd));
 491                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
 492         }
 493
 494         return rtn;
 495 }
 496
 497 static void __scsi_report_device_reset(struct scsi_device *sdev, void *data)
 498 {
 499         sdev->was_reset = 1;
 500         sdev->expecting_cc_ua = 1;
 501 }
 502
 503 /**
 504  * scsi_try_target_reset - Ask host to perform a target reset
 505  * @scmd:       SCSI cmd used to send a target reset
 506  *
 507  * Notes:
 508  *    There is no timeout for this operation.  if this operation is
 509  *    unreliable for a given host, then the host itself needs to put a
 510  *    timer on it, and set the host back to a consistent state prior to
 511  *    returning.
 512  */
 513 static int scsi_try_target_reset(struct scsi_cmnd *scmd)
 514 {
 515         unsigned long flags;
 516         int rtn;
 517
 518         if (!scmd->device->host->hostt->eh_target_reset_handler)
 519                 return FAILED;
 520
 521         rtn = scmd->device->host->hostt->eh_target_reset_handler(scmd);
 522         if (rtn == SUCCESS) {
 523                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
 524                 __starget_for_each_device(scsi_target(scmd->device), NULL,
 525                                           __scsi_report_device_reset);
 526                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
 527         }
 528
 529         return rtn;
 530 }
 531
 532 /**
 533  * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
 534  * @scmd:       SCSI cmd used to send BDR
 535  *
 536  * Notes:
 537  *    There is no timeout for this operation.  if this operation is
 538  *    unreliable for a given host, then the host itself needs to put a
 539  *    timer on it, and set the host back to a consistent state prior to
 540  *    returning.
 541  */
 542 static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
 543 {
 544         int rtn;
 545
 546         if (!scmd->device->host->hostt->eh_device_reset_handler)
 547                 return FAILED;
 548
 549         rtn = scmd->device->host->hostt->eh_device_reset_handler(scmd);
 550         if (rtn == SUCCESS)
 551                 __scsi_report_device_reset(scmd->device, NULL);
 552         return rtn;
 553 }
 554
 555 static int __scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
 556 {
 557         if (!scmd->device->host->hostt->eh_abort_handler)
 558                 return FAILED;
 559
 560         return scmd->device->host->hostt->eh_abort_handler(scmd);
 561 }
 562
 563 /**
 564  * scsi_try_to_abort_cmd - Ask host to abort a running command.
 565  * @scmd:       SCSI cmd to abort from Lower Level.
 566  *
 567  * Notes:
 568  *    This function will not return until the user's completion function
 569  *    has been called.  there is no timeout on this operation.  if the
 570  *    author of the low-level driver wishes this operation to be timed,
 571  *    they can provide this facility themselves.  helper functions in
 572  *    scsi_error.c can be supplied to make this easier to do.
 573  */
 574 static int scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
 575 {
 576         /*
 577          * scsi_done was called just after the command timed out and before
 578          * we had a chance to process it. (db)
 579          */
 580         if (scmd->serial_number == 0)
 581                 return SUCCESS;
 582         return __scsi_try_to_abort_cmd(scmd);
 583 }
 584
 585 static void scsi_abort_eh_cmnd(struct scsi_cmnd *scmd)
 586 {
 587         if (__scsi_try_to_abort_cmd(scmd) != SUCCESS)
 588                 if (scsi_try_bus_device_reset(scmd) != SUCCESS)
 589                         if (scsi_try_target_reset(scmd) != SUCCESS)
 590                                 if (scsi_try_bus_reset(scmd) != SUCCESS)
 591                                         scsi_try_host_reset(scmd);
 592 }
 593
 594 /**
 595  * scsi_eh_prep_cmnd  - Save a scsi command info as part of error recory
 596  * @scmd:       SCSI command structure to hijack
 597  * @ses:        structure to save restore information
 598  * @cmnd:       CDB to send. Can be NULL if no new cmnd is needed
 599  * @cmnd_size:  size in bytes of @cmnd (must be <= BLK_MAX_CDB)
 600  * @sense_bytes: size of sense data to copy. or 0 (if != 0 @cmnd is ignored)
 601  *
 602  * This function is used to save a scsi command information before re-execution
 603  * as part of the error recovery process.  If @sense_bytes is 0 the command
 604  * sent must be one that does not transfer any data.  If @sense_bytes != 0
 605  * @cmnd is ignored and this functions sets up a REQUEST_SENSE command
 606  * and cmnd buffers to read @sense_bytes into @scmd->sense_buffer.
 607  */
 608 void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses,
 609                         unsigned char *cmnd, int cmnd_size, unsigned sense_bytes)
 610 {
 611         struct scsi_device *sdev = scmd->device;
 612
 613         /*
 614          * We need saved copies of a number of fields - this is because
 615          * error handling may need to overwrite these with different values
 616          * to run different commands, and once error handling is complete,
 617          * we will need to restore these values prior to running the actual
 618          * command.
 619          */
 620         ses->cmd_len = scmd->cmd_len;
 621         ses->cmnd = scmd->cmnd;
 622         ses->data_direction = scmd->sc_data_direction;
 623         ses->sdb = scmd->sdb;
 624         ses->next_rq = scmd->request->next_rq;
 625         ses->result = scmd->result;
 626         ses->underflow = scmd->underflow;
 627         ses->prot_op = scmd->prot_op;
 628
 629         scmd->prot_op = SCSI_PROT_NORMAL;
 630         scmd->cmnd = ses->eh_cmnd;
 631         memset(scmd->cmnd, 0, BLK_MAX_CDB);
 632         memset(&scmd->sdb, 0, sizeof(scmd->sdb));
 633         scmd->request->next_rq = NULL;
 634
 635         if (sense_bytes) {
 636                 scmd->sdb.length = min_t(unsigned, SCSI_SENSE_BUFFERSIZE,
 637                                          sense_bytes);
 638                 sg_init_one(&ses->sense_sgl, scmd->sense_buffer,
 639                             scmd->sdb.length);
 640                 scmd->sdb.table.sgl = &ses->sense_sgl;
 641                 scmd->sc_data_direction = DMA_FROM_DEVICE;
 642                 scmd->sdb.table.nents = 1;
 643                 scmd->cmnd[0] = REQUEST_SENSE;
 644                 scmd->cmnd[4] = scmd->sdb.length;
 645                 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
 646         } else {
 647                 scmd->sc_data_direction = DMA_NONE;
 648                 if (cmnd) {
 649                         BUG_ON(cmnd_size > BLK_MAX_CDB);
 650                         memcpy(scmd->cmnd, cmnd, cmnd_size);
 651                         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
 652                 }
 653         }
 654
 655         scmd->underflow = 0;
 656
 657         if (sdev->scsi_level <= SCSI_2 && sdev->scsi_level != SCSI_UNKNOWN)
 658                 scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
 659                         (sdev->lun << 5 & 0xe0);
 660
 661         /*
 662          * Zero the sense buffer.  The scsi spec mandates that any
 663          * untransferred sense data should be interpreted as being zero.
 664          */
 665         memset(scmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
 666 }
 667 EXPORT_SYMBOL(scsi_eh_prep_cmnd);
 668
 669 /**
 670  * scsi_eh_restore_cmnd  - Restore a scsi command info as part of error recory
 671  * @scmd:       SCSI command structure to restore
 672  * @ses:        saved information from a coresponding call to scsi_eh_prep_cmnd
 673  *
 674  * Undo any damage done by above scsi_eh_prep_cmnd().
 675  */
 676 void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct scsi_eh_save *ses)
 677 {
 678         /*
 679          * Restore original data
 680          */
 681         scmd->cmd_len = ses->cmd_len;
 682         scmd->cmnd = ses->cmnd;
 683         scmd->sc_data_direction = ses->data_direction;
 684         scmd->sdb = ses->sdb;
 685         scmd->request->next_rq = ses->next_rq;
 686         scmd->result = ses->result;
 687         scmd->underflow = ses->underflow;
 688         scmd->prot_op = ses->prot_op;
 689 }
 690 EXPORT_SYMBOL(scsi_eh_restore_cmnd);
 691
 692 /**
 693  * scsi_send_eh_cmnd  - submit a scsi command as part of error recory
 694  * @scmd:       SCSI command structure to hijack
 695  * @cmnd:       CDB to send
 696  * @cmnd_size:  size in bytes of @cmnd
 697  * @timeout:    timeout for this request
 698  * @sense_bytes: size of sense data to copy or 0
 699  *
 700  * This function is used to send a scsi command down to a target device
 701  * as part of the error recovery process. See also scsi_eh_prep_cmnd() above.
 702  *
 703  * Return value:
 704  *    SUCCESS or FAILED or NEEDS_RETRY
 705  */
 706 static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd,
 707                              int cmnd_size, int timeout, unsigned sense_bytes)
 708 {
 709         struct scsi_device *sdev = scmd->device;
 710         struct Scsi_Host *shost = sdev->host;
 711         DECLARE_COMPLETION_ONSTACK(done);
 712         unsigned long timeleft;
 713         unsigned long flags;
 714         struct scsi_eh_save ses;
 715         int rtn;
 716
 717         scsi_eh_prep_cmnd(scmd, &ses, cmnd, cmnd_size, sense_bytes);
 718         shost->eh_action = &done;
 719
 720         spin_lock_irqsave(shost->host_lock, flags);
 721         scsi_log_send(scmd);
 722         shost->hostt->queuecommand(scmd, scsi_eh_done);
 723         spin_unlock_irqrestore(shost->host_lock, flags);
 724
 725         timeleft = wait_for_completion_timeout(&done, timeout);
 726
 727         shost->eh_action = NULL;
 728
 729         scsi_log_completion(scmd, SUCCESS);
 730
 731         SCSI_LOG_ERROR_RECOVERY(3,
 732                 printk("%s: scmd: %p, timeleft: %ld\n",
 733                         __func__, scmd, timeleft));
 734
 735         /*
 736          * If there is time left scsi_eh_done got called, and we will
 737          * examine the actual status codes to see whether the command
 738          * actually did complete normally, else tell the host to forget
 739          * about this command.
 740          */
 741         if (timeleft) {
 742                 rtn = scsi_eh_completed_normally(scmd);
 743                 SCSI_LOG_ERROR_RECOVERY(3,
 744                         printk("%s: scsi_eh_completed_normally %x\n",
 745                                __func__, rtn));
 746
 747                 switch (rtn) {
 748                 case SUCCESS:
 749                 case NEEDS_RETRY:
 750                 case FAILED:
 751                         break;
 752                 case ADD_TO_MLQUEUE:
 753                         rtn = NEEDS_RETRY;
 754                         break;
 755                 default:
 756                         rtn = FAILED;
 757                         break;
 758                 }
 759         } else {
 760                 scsi_abort_eh_cmnd(scmd);
 761                 rtn = FAILED;
 762         }
 763
 764         scsi_eh_restore_cmnd(scmd, &ses);
 765         return rtn;
 766 }
 767
 768 /**
 769  * scsi_request_sense - Request sense data from a particular target.
 770  * @scmd:       SCSI cmd for request sense.
 771  *
 772  * Notes:
 773  *    Some hosts automatically obtain this information, others require
 774  *    that we obtain it on our own. This function will *not* return until
 775  *    the command either times out, or it completes.
 776  */
 777 static int scsi_request_sense(struct scsi_cmnd *scmd)
 778 {
 779         return scsi_send_eh_cmnd(scmd, NULL, 0, SENSE_TIMEOUT, ~0);
 780 }
 781
 782 /**
 783  * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
 784  * @scmd:       Original SCSI cmd that eh has finished.
 785  * @done_q:     Queue for processed commands.
 786  *
 787  * Notes:
 788  *    We don't want to use the normal command completion while we are are
 789  *    still handling errors - it may cause other commands to be queued,
 790  *    and that would disturb what we are doing.  Thus we really want to
 791  *    keep a list of pending commands for final completion, and once we
 792  *    are ready to leave error handling we handle completion for real.
 793  */
 794 void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)
 795 {
 796         scmd->device->host->host_failed--;
 797         scmd->eh_eflags = 0;
 798         list_move_tail(&scmd->eh_entry, done_q);
 799 }
 800 EXPORT_SYMBOL(scsi_eh_finish_cmd);
 801
 802 /**
 803  * scsi_eh_get_sense - Get device sense data.
 804  * @work_q:     Queue of commands to process.
 805  * @done_q:     Queue of processed commands.
 806  *
 807  * Description:
 808  *    See if we need to request sense information.  if so, then get it
 809  *    now, so we have a better idea of what to do.
 810  *
 811  * Notes:
 812  *    This has the unfortunate side effect that if a shost adapter does
 813  *    not automatically request sense information, we end up shutting
 814  *    it down before we request it.
 815  *
 816  *    All drivers should request sense information internally these days,
 817  *    so for now all I have to say is tough noogies if you end up in here.
 818  *
 819  *    XXX: Long term this code should go away, but that needs an audit of
 820  *         all LLDDs first.
 821  */
 822 int scsi_eh_get_sense(struct list_head *work_q,
 823                       struct list_head *done_q)
 824 {
 825         struct scsi_cmnd *scmd, *next;
 826         int rtn;
 827
 828         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
 829                 if ((scmd->eh_eflags & SCSI_EH_CANCEL_CMD) ||
 830                     SCSI_SENSE_VALID(scmd))
 831                         continue;
 832
 833                 SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd,
 834                                                   "%s: requesting sense\n",
 835                                                   current->comm));
 836                 rtn = scsi_request_sense(scmd);
 837                 if (rtn != SUCCESS)
 838                         continue;
 839
 840                 SCSI_LOG_ERROR_RECOVERY(3, printk("sense requested for %p"
 841                                                   " result %x\n", scmd,
 842                                                   scmd->result));
 843                 SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense("bh", scmd));
 844
 845                 rtn = scsi_decide_disposition(scmd);
 846
 847                 /*
 848                  * if the result was normal, then just pass it along to the
 849                  * upper level.
 850                  */
 851                 if (rtn == SUCCESS)
 852                         /* we don't want this command reissued, just
 853                          * finished with the sense data, so set
 854                          * retries to the max allowed to ensure it
 855                          * won't get reissued */
 856                         scmd->retries = scmd->allowed;
 857                 else if (rtn != NEEDS_RETRY)
 858                         continue;
 859
 860                 scsi_eh_finish_cmd(scmd, done_q);
 861         }
 862
 863         return list_empty(work_q);
 864 }
 865 EXPORT_SYMBOL_GPL(scsi_eh_get_sense);
 866
 867 /**
 868  * scsi_eh_tur - Send TUR to device.
 869  * @scmd:       &scsi_cmnd to send TUR
 870  *
 871  * Return value:
 872  *    0 - Device is ready. 1 - Device NOT ready.
 873  */
 874 static int scsi_eh_tur(struct scsi_cmnd *scmd)
 875 {
 876         static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
 877         int retry_cnt = 1, rtn;
 878
 879 retry_tur:
 880         rtn = scsi_send_eh_cmnd(scmd, tur_command, 6, SENSE_TIMEOUT, 0);
 881
 882         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
 883                 __func__, scmd, rtn));
 884
 885         switch (rtn) {
 886         case NEEDS_RETRY:
 887                 if (retry_cnt--)
 888                         goto retry_tur;
 889                 /*FALLTHRU*/
 890         case SUCCESS:
 891                 return 0;
 892         default:
 893                 return 1;
 894         }
 895 }
 896
 897 /**
 898  * scsi_eh_abort_cmds - abort pending commands.
 899  * @work_q:     &list_head for pending commands.
 900  * @done_q:     &list_head for processed commands.
 901  *
 902  * Decription:
 903  *    Try and see whether or not it makes sense to try and abort the
 904  *    running command.  This only works out to be the case if we have one
 905  *    command that has timed out.  If the command simply failed, it makes
 906  *    no sense to try and abort the command, since as far as the shost
 907  *    adapter is concerned, it isn't running.
 908  */
 909 static int scsi_eh_abort_cmds(struct list_head *work_q,
 910                               struct list_head *done_q)
 911 {
 912         struct scsi_cmnd *scmd, *next;
 913         int rtn;
 914
 915         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
 916                 if (!(scmd->eh_eflags & SCSI_EH_CANCEL_CMD))
 917                         continue;
 918                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting cmd:"
 919                                                   "0x%p\n", current->comm,
 920                                                   scmd));
 921                 rtn = scsi_try_to_abort_cmd(scmd);
 922                 if (rtn == SUCCESS) {
 923                         scmd->eh_eflags &= ~SCSI_EH_CANCEL_CMD;
 924                         if (!scsi_device_online(scmd->device) ||
 925                             !scsi_eh_tur(scmd)) {
 926                                 scsi_eh_finish_cmd(scmd, done_q);
 927                         }
 928
 929                 } else
 930                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting"
 931                                                           " cmd failed:"
 932                                                           "0x%p\n",
 933                                                           current->comm,
 934                                                           scmd));
 935         }
 936
 937         return list_empty(work_q);
 938 }
 939
 940 /**
 941  * scsi_eh_try_stu - Send START_UNIT to device.
 942  * @scmd:       &scsi_cmnd to send START_UNIT
 943  *
 944  * Return value:
 945  *    0 - Device is ready. 1 - Device NOT ready.
 946  */
 947 static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
 948 {
 949         static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
 950
 951         if (scmd->device->allow_restart) {
 952                 int i, rtn = NEEDS_RETRY;
 953
 954                 for (i = 0; rtn == NEEDS_RETRY && i < 2; i++)
 955                         rtn = scsi_send_eh_cmnd(scmd, stu_command, 6, scmd->device->request_queue->rq_timeout, 0);
 956
 957                 if (rtn == SUCCESS)
 958                         return 0;
 959         }
 960
 961         return 1;
 962 }
 963
 964  /**
 965  * scsi_eh_stu - send START_UNIT if needed
 966  * @shost:      &scsi host being recovered.
 967  * @work_q:     &list_head for pending commands.
 968  * @done_q:     &list_head for processed commands.
 969  *
 970  * Notes:
 971  *    If commands are failing due to not ready, initializing command required,
 972  *      try revalidating the device, which will end up sending a start unit.
 973  */
 974 static int scsi_eh_stu(struct Scsi_Host *shost,
 975                               struct list_head *work_q,
 976                               struct list_head *done_q)
 977 {
 978         struct scsi_cmnd *scmd, *stu_scmd, *next;
 979         struct scsi_device *sdev;
 980
 981         shost_for_each_device(sdev, shost) {
 982                 stu_scmd = NULL;
 983                 list_for_each_entry(scmd, work_q, eh_entry)
 984                         if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
 985                             scsi_check_sense(scmd) == FAILED ) {
 986                                 stu_scmd = scmd;
 987                                 break;
 988                         }
 989
 990                 if (!stu_scmd)
 991                         continue;
 992
 993                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending START_UNIT to sdev:"
 994                                                   " 0x%p\n", current->comm, sdev));
 995
 996                 if (!scsi_eh_try_stu(stu_scmd)) {
 997                         if (!scsi_device_online(sdev) ||
 998                             !scsi_eh_tur(stu_scmd)) {
 999                                 list_for_each_entry_safe(scmd, next,
1000                                                           work_q, eh_entry) {
1001                                         if (scmd->device == sdev)
1002                                                 scsi_eh_finish_cmd(scmd, done_q);
1003                                 }
1004                         }
1005                 } else {
1006                         SCSI_LOG_ERROR_RECOVERY(3,
1007                                                 printk("%s: START_UNIT failed to sdev:"
1008                                                        " 0x%p\n", current->comm, sdev));
1009                 }
1010         }
1011
1012         return list_empty(work_q);
1013 }
1014
1015
1016 /**
1017  * scsi_eh_bus_device_reset - send bdr if needed
1018  * @shost:      scsi host being recovered.
1019  * @work_q:     &list_head for pending commands.
1020  * @done_q:     &list_head for processed commands.
1021  *
1022  * Notes:
1023  *    Try a bus device reset.  Still, look to see whether we have multiple
1024  *    devices that are jammed or not - if we have multiple devices, it
1025  *    makes no sense to try bus_device_reset - we really would need to try
1026  *    a bus_reset instead.
1027  */
1028 static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
1029                                     struct list_head *work_q,
1030                                     struct list_head *done_q)
1031 {
1032         struct scsi_cmnd *scmd, *bdr_scmd, *next;
1033         struct scsi_device *sdev;
1034         int rtn;
1035
1036         shost_for_each_device(sdev, shost) {
1037                 bdr_scmd = NULL;
1038                 list_for_each_entry(scmd, work_q, eh_entry)
1039                         if (scmd->device == sdev) {
1040                                 bdr_scmd = scmd;
1041                                 break;
1042                         }
1043
1044                 if (!bdr_scmd)
1045                         continue;
1046
1047                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BDR sdev:"
1048                                                   " 0x%p\n", current->comm,
1049                                                   sdev));
1050                 rtn = scsi_try_bus_device_reset(bdr_scmd);
1051                 if (rtn == SUCCESS) {
1052                         if (!scsi_device_online(sdev) ||
1053                             !scsi_eh_tur(bdr_scmd)) {
1054                                 list_for_each_entry_safe(scmd, next,
1055                                                          work_q, eh_entry) {
1056                                         if (scmd->device == sdev)
1057                                                 scsi_eh_finish_cmd(scmd,
1058                                                                    done_q);
1059                                 }
1060                         }
1061                 } else {
1062                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BDR"
1063                                                           " failed sdev:"
1064                                                           "0x%p\n",
1065                                                           current->comm,
1066                                                            sdev));
1067                 }
1068         }
1069
1070         return list_empty(work_q);
1071 }
1072
1073 /**
1074  * scsi_eh_target_reset - send target reset if needed
1075  * @shost:      scsi host being recovered.
1076  * @work_q:     &list_head for pending commands.
1077  * @done_q:     &list_head for processed commands.
1078  *
1079  * Notes:
1080  *    Try a target reset.
1081  */
1082 static int scsi_eh_target_reset(struct Scsi_Host *shost,
1083                                 struct list_head *work_q,
1084                                 struct list_head *done_q)
1085 {
1086         struct scsi_cmnd *scmd, *tgtr_scmd, *next;
1087         unsigned int id = 0;
1088         int rtn;
1089
1090         do {
1091                 tgtr_scmd = NULL;
1092                 list_for_each_entry(scmd, work_q, eh_entry) {
1093                         if (id == scmd_id(scmd)) {
1094                                 tgtr_scmd = scmd;
1095                                 break;
1096                         }
1097                 }
1098                 if (!tgtr_scmd) {
1099                         /* not one exactly equal; find the next highest */
1100                         list_for_each_entry(scmd, work_q, eh_entry) {
1101                                 if (scmd_id(scmd) > id &&
1102                                     (!tgtr_scmd ||
1103                                      scmd_id(tgtr_scmd) > scmd_id(scmd)))
1104                                                 tgtr_scmd = scmd;
1105                         }
1106                 }
1107                 if (!tgtr_scmd)
1108                         /* no more commands, that's it */
1109                         break;
1110
1111                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending target reset "
1112                                                   "to target %d\n",
1113                                                   current->comm, id));
1114                 rtn = scsi_try_target_reset(tgtr_scmd);
1115                 if (rtn == SUCCESS) {
1116                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1117                                 if (id == scmd_id(scmd))
1118                                         if (!scsi_device_online(scmd->device) ||
1119                                             !scsi_eh_tur(tgtr_scmd))
1120                                                 scsi_eh_finish_cmd(scmd,
1121                                                                    done_q);
1122                         }
1123                 } else
1124                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Target reset"
1125                                                           " failed target: "
1126                                                           "%d\n",
1127                                                           current->comm, id));
1128                 id++;
1129         } while(id != 0);
1130
1131         return list_empty(work_q);
1132 }
1133
1134 /**
1135  * scsi_eh_bus_reset - send a bus reset
1136  * @shost:      &scsi host being recovered.
1137  * @work_q:     &list_head for pending commands.
1138  * @done_q:     &list_head for processed commands.
1139  */
1140 static int scsi_eh_bus_reset(struct Scsi_Host *shost,
1141                              struct list_head *work_q,
1142                              struct list_head *done_q)
1143 {
1144         struct scsi_cmnd *scmd, *chan_scmd, *next;
1145         unsigned int channel;
1146         int rtn;
1147
1148         /*
1149          * we really want to loop over the various channels, and do this on
1150          * a channel by channel basis.  we should also check to see if any
1151          * of the failed commands are on soft_reset devices, and if so, skip
1152          * the reset.
1153          */
1154
1155         for (channel = 0; channel <= shost->max_channel; channel++) {
1156                 chan_scmd = NULL;
1157                 list_for_each_entry(scmd, work_q, eh_entry) {
1158                         if (channel == scmd_channel(scmd)) {
1159                                 chan_scmd = scmd;
1160                                 break;
1161                                 /*
1162                                  * FIXME add back in some support for
1163                                  * soft_reset devices.
1164                                  */
1165                         }
1166                 }
1167
1168                 if (!chan_scmd)
1169                         continue;
1170                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BRST chan:"
1171                                                   " %d\n", current->comm,
1172                                                   channel));
1173                 rtn = scsi_try_bus_reset(chan_scmd);
1174                 if (rtn == SUCCESS) {
1175                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1176                                 if (channel == scmd_channel(scmd))
1177                                         if (!scsi_device_online(scmd->device) ||
1178                                             !scsi_eh_tur(scmd))
1179                                                 scsi_eh_finish_cmd(scmd,
1180                                                                    done_q);
1181                         }
1182                 } else {
1183                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BRST"
1184                                                           " failed chan: %d\n",
1185                                                           current->comm,
1186                                                           channel));
1187                 }
1188         }
1189         return list_empty(work_q);
1190 }
1191
1192 /**
1193  * scsi_eh_host_reset - send a host reset
1194  * @work_q:     list_head for processed commands.
1195  * @done_q:     list_head for processed commands.
1196  */
1197 static int scsi_eh_host_reset(struct list_head *work_q,
1198                               struct list_head *done_q)
1199 {
1200         struct scsi_cmnd *scmd, *next;
1201         int rtn;
1202
1203         if (!list_empty(work_q)) {
1204                 scmd = list_entry(work_q->next,
1205                                   struct scsi_cmnd, eh_entry);
1206
1207                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending HRST\n"
1208                                                   , current->comm));
1209
1210                 rtn = scsi_try_host_reset(scmd);
1211                 if (rtn == SUCCESS) {
1212                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1213                                 if (!scsi_device_online(scmd->device) ||
1214                                     (!scsi_eh_try_stu(scmd) && !scsi_eh_tur(scmd)) ||
1215                                     !scsi_eh_tur(scmd))
1216                                         scsi_eh_finish_cmd(scmd, done_q);
1217                         }
1218                 } else {
1219                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: HRST"
1220                                                           " failed\n",
1221                                                           current->comm));
1222                 }
1223         }
1224         return list_empty(work_q);
1225 }
1226
1227 /**
1228  * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
1229  * @work_q:     list_head for processed commands.
1230  * @done_q:     list_head for processed commands.
1231  */
1232 static void scsi_eh_offline_sdevs(struct list_head *work_q,
1233                                   struct list_head *done_q)
1234 {
1235         struct scsi_cmnd *scmd, *next;
1236
1237         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1238                 sdev_printk(KERN_INFO, scmd->device, "Device offlined - "
1239                             "not ready after error recovery\n");
1240                 scsi_device_set_state(scmd->device, SDEV_OFFLINE);
1241                 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD) {
1242                         /*
1243                          * FIXME: Handle lost cmds.
1244                          */
1245                 }
1246                 scsi_eh_finish_cmd(scmd, done_q);
1247         }
1248         return;
1249 }
1250
1251 /**
1252  * scsi_noretry_cmd - determinte if command should be failed fast
1253  * @scmd:       SCSI cmd to examine.
1254  */
1255 int scsi_noretry_cmd(struct scsi_cmnd *scmd)
1256 {
1257         switch (host_byte(scmd->result)) {
1258         case DID_OK:
1259                 break;
1260         case DID_BUS_BUSY:
1261                 return blk_failfast_transport(scmd->request);
1262         case DID_PARITY:
1263                 return blk_failfast_dev(scmd->request);
1264         case DID_ERROR:
1265                 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1266                     status_byte(scmd->result) == RESERVATION_CONFLICT)
1267                         return 0;
1268                 /* fall through */
1269         case DID_SOFT_ERROR:
1270                 return blk_failfast_driver(scmd->request);
1271         }
1272
1273         switch (status_byte(scmd->result)) {
1274         case CHECK_CONDITION:
1275                 /*
1276                  * assume caller has checked sense and determinted
1277                  * the check condition was retryable.
1278                  */
1279                 return blk_failfast_dev(scmd->request);
1280         }
1281
1282         return 0;
1283 }
1284
1285 /**
1286  * scsi_decide_disposition - Disposition a cmd on return from LLD.
1287  * @scmd:       SCSI cmd to examine.
1288  *
1289  * Notes:
1290  *    This is *only* called when we are examining the status after sending
1291  *    out the actual data command.  any commands that are queued for error
1292  *    recovery (e.g. test_unit_ready) do *not* come through here.
1293  *
1294  *    When this routine returns failed, it means the error handler thread
1295  *    is woken.  In cases where the error code indicates an error that
1296  *    doesn't require the error handler read (i.e. we don't need to
1297  *    abort/reset), this function should return SUCCESS.
1298  */
1299 int scsi_decide_disposition(struct scsi_cmnd *scmd)
1300 {
1301         int rtn;
1302
1303         /*
1304          * if the device is offline, then we clearly just pass the result back
1305          * up to the top level.
1306          */
1307         if (!scsi_device_online(scmd->device)) {
1308                 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: device offline - report"
1309                                                   " as SUCCESS\n",
1310                                                   __func__));
1311                 return SUCCESS;
1312         }
1313
1314         /*
1315          * first check the host byte, to see if there is anything in there
1316          * that would indicate what we need to do.
1317          */
1318         switch (host_byte(scmd->result)) {
1319         case DID_PASSTHROUGH:
1320                 /*
1321                  * no matter what, pass this through to the upper layer.
1322                  * nuke this special code so that it looks like we are saying
1323                  * did_ok.
1324                  */
1325                 scmd->result &= 0xff00ffff;
1326                 return SUCCESS;
1327         case DID_OK:
1328                 /*
1329                  * looks good.  drop through, and check the next byte.
1330                  */
1331                 break;
1332         case DID_NO_CONNECT:
1333         case DID_BAD_TARGET:
1334         case DID_ABORT:
1335                 /*
1336                  * note - this means that we just report the status back
1337                  * to the top level driver, not that we actually think
1338                  * that it indicates SUCCESS.
1339                  */
1340                 return SUCCESS;
1341                 /*
1342                  * when the low level driver returns did_soft_error,
1343                  * it is responsible for keeping an internal retry counter
1344                  * in order to avoid endless loops (db)
1345                  *
1346                  * actually this is a bug in this function here.  we should
1347                  * be mindful of the maximum number of retries specified
1348                  * and not get stuck in a loop.
1349                  */
1350         case DID_SOFT_ERROR:
1351                 goto maybe_retry;
1352         case DID_IMM_RETRY:
1353                 return NEEDS_RETRY;
1354
1355         case DID_REQUEUE:
1356                 return ADD_TO_MLQUEUE;
1357         case DID_TRANSPORT_DISRUPTED:
1358                 /*
1359                  * LLD/transport was disrupted during processing of the IO.
1360                  * The transport class is now blocked/blocking,
1361                  * and the transport will decide what to do with the IO
1362                  * based on its timers and recovery capablilities if
1363                  * there are enough retries.
1364                  */
1365                 goto maybe_retry;
1366         case DID_TRANSPORT_FAILFAST:
1367                 /*
1368                  * The transport decided to failfast the IO (most likely
1369                  * the fast io fail tmo fired), so send IO directly upwards.
1370                  */
1371                 return SUCCESS;
1372         case DID_ERROR:
1373                 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1374                     status_byte(scmd->result) == RESERVATION_CONFLICT)
1375                         /*
1376                          * execute reservation conflict processing code
1377                          * lower down
1378                          */
1379                         break;
1380                 /* fallthrough */
1381
1382         case DID_BUS_BUSY:
1383         case DID_PARITY:
1384                 goto maybe_retry;
1385         case DID_TIME_OUT:
1386                 /*
1387                  * when we scan the bus, we get timeout messages for
1388                  * these commands if there is no device available.
1389                  * other hosts report did_no_connect for the same thing.
1390                  */
1391                 if ((scmd->cmnd[0] == TEST_UNIT_READY ||
1392                      scmd->cmnd[0] == INQUIRY)) {
1393                         return SUCCESS;
1394                 } else {
1395                         return FAILED;
1396                 }
1397         case DID_RESET:
1398                 return SUCCESS;
1399         default:
1400                 return FAILED;
1401         }
1402
1403         /*
1404          * next, check the message byte.
1405          */
1406         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
1407                 return FAILED;
1408
1409         /*
1410          * check the status byte to see if this indicates anything special.
1411          */
1412         switch (status_byte(scmd->result)) {
1413         case QUEUE_FULL:
1414                 scsi_handle_queue_full(scmd->device);
1415                 /*
1416                  * the case of trying to send too many commands to a
1417                  * tagged queueing device.
1418                  */
1419         case BUSY:
1420                 /*
1421                  * device can't talk to us at the moment.  Should only
1422                  * occur (SAM-3) when the task queue is empty, so will cause
1423                  * the empty queue handling to trigger a stall in the
1424                  * device.
1425                  */
1426                 return ADD_TO_MLQUEUE;
1427         case GOOD:
1428         case COMMAND_TERMINATED:
1429                 return SUCCESS;
1430         case TASK_ABORTED:
1431                 goto maybe_retry;
1432         case CHECK_CONDITION:
1433                 rtn = scsi_check_sense(scmd);
1434                 if (rtn == NEEDS_RETRY)
1435                         goto maybe_retry;
1436                 /* if rtn == FAILED, we have no sense information;
1437                  * returning FAILED will wake the error handler thread
1438                  * to collect the sense and redo the decide
1439                  * disposition */
1440                 return rtn;
1441         case CONDITION_GOOD:
1442         case INTERMEDIATE_GOOD:
1443         case INTERMEDIATE_C_GOOD:
1444         case ACA_ACTIVE:
1445                 /*
1446                  * who knows?  FIXME(eric)
1447                  */
1448                 return SUCCESS;
1449
1450         case RESERVATION_CONFLICT:
1451                 sdev_printk(KERN_INFO, scmd->device,
1452                             "reservation conflict\n");
1453                 return SUCCESS; /* causes immediate i/o error */
1454         default:
1455                 return FAILED;
1456         }
1457         return FAILED;
1458
1459       maybe_retry:
1460
1461         /* we requeue for retry because the error was retryable, and
1462          * the request was not marked fast fail.  Note that above,
1463          * even if the request is marked fast fail, we still requeue
1464          * for queue congestion conditions (QUEUE_FULL or BUSY) */
1465         if ((++scmd->retries) <= scmd->allowed
1466             && !scsi_noretry_cmd(scmd)) {
1467                 return NEEDS_RETRY;
1468         } else {
1469                 /*
1470                  * no more retries - report this one back to upper level.
1471                  */
1472                 return SUCCESS;
1473         }
1474 }
1475
1476 static void eh_lock_door_done(struct request *req, int uptodate)
1477 {
1478         __blk_put_request(req->q, req);
1479 }
1480
1481 /**
1482  * scsi_eh_lock_door - Prevent medium removal for the specified device
1483  * @sdev:       SCSI device to prevent medium removal
1484  *
1485  * Locking:
1486  *      We must be called from process context.
1487  *
1488  * Notes:
1489  *      We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
1490  *      head of the devices request queue, and continue.
1491  */
1492 static void scsi_eh_lock_door(struct scsi_device *sdev)
1493 {
1494         struct request *req;
1495
1496         /*
1497          * blk_get_request with GFP_KERNEL (__GFP_WAIT) sleeps until a
1498          * request becomes available
1499          */
1500         req = blk_get_request(sdev->request_queue, READ, GFP_KERNEL);
1501
1502         req->cmd[0] = ALLOW_MEDIUM_REMOVAL;
1503         req->cmd[1] = 0;
1504         req->cmd[2] = 0;
1505         req->cmd[3] = 0;
1506         req->cmd[4] = SCSI_REMOVAL_PREVENT;
1507         req->cmd[5] = 0;
1508
1509         req->cmd_len = COMMAND_SIZE(req->cmd[0]);
1510
1511         req->cmd_type = REQ_TYPE_BLOCK_PC;
1512         req->cmd_flags |= REQ_QUIET;
1513         req->timeout = 10 * HZ;
1514         req->retries = 5;
1515
1516         blk_execute_rq_nowait(req->q, NULL, req, 1, eh_lock_door_done);
1517 }
1518
1519 /**
1520  * scsi_restart_operations - restart io operations to the specified host.
1521  * @shost:      Host we are restarting.
1522  *
1523  * Notes:
1524  *    When we entered the error handler, we blocked all further i/o to
1525  *    this device.  we need to 'reverse' this process.
1526  */
1527 static void scsi_restart_operations(struct Scsi_Host *shost)
1528 {
1529         struct scsi_device *sdev;
1530         unsigned long flags;
1531
1532         /*
1533          * If the door was locked, we need to insert a door lock request
1534          * onto the head of the SCSI request queue for the device.  There
1535          * is no point trying to lock the door of an off-line device.
1536          */
1537         shost_for_each_device(sdev, shost) {
1538                 if (scsi_device_online(sdev) && sdev->locked)
1539                         scsi_eh_lock_door(sdev);
1540         }
1541
1542         /*
1543          * next free up anything directly waiting upon the host.  this
1544          * will be requests for character device operations, and also for
1545          * ioctls to queued block devices.
1546          */
1547         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: waking up host to restart\n",
1548                                           __func__));
1549
1550         spin_lock_irqsave(shost->host_lock, flags);
1551         if (scsi_host_set_state(shost, SHOST_RUNNING))
1552                 if (scsi_host_set_state(shost, SHOST_CANCEL))
1553                         BUG_ON(scsi_host_set_state(shost, SHOST_DEL));
1554         spin_unlock_irqrestore(shost->host_lock, flags);
1555
1556         wake_up(&shost->host_wait);
1557
1558         /*
1559          * finally we need to re-initiate requests that may be pending.  we will
1560          * have had everything blocked while error handling is taking place, and
1561          * now that error recovery is done, we will need to ensure that these
1562          * requests are started.
1563          */
1564         scsi_run_host_queues(shost);
1565 }
1566
1567 /**
1568  * scsi_eh_ready_devs - check device ready state and recover if not.
1569  * @shost:      host to be recovered.
1570  * @work_q:     &list_head for pending commands.
1571  * @done_q:     &list_head for processed commands.
1572  */
1573 void scsi_eh_ready_devs(struct Scsi_Host *shost,
1574                         struct list_head *work_q,
1575                         struct list_head *done_q)
1576 {
1577         if (!scsi_eh_stu(shost, work_q, done_q))
1578                 if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
1579                         if (!scsi_eh_target_reset(shost, work_q, done_q))
1580                                 if (!scsi_eh_bus_reset(shost, work_q, done_q))
1581                                         if (!scsi_eh_host_reset(work_q, done_q))
1582                                                 scsi_eh_offline_sdevs(work_q,
1583                                                                       done_q);
1584 }
1585 EXPORT_SYMBOL_GPL(scsi_eh_ready_devs);
1586
1587 /**
1588  * scsi_eh_flush_done_q - finish processed commands or retry them.
1589  * @done_q:     list_head of processed commands.
1590  */
1591 void scsi_eh_flush_done_q(struct list_head *done_q)
1592 {
1593         struct scsi_cmnd *scmd, *next;
1594
1595         list_for_each_entry_safe(scmd, next, done_q, eh_entry) {
1596                 list_del_init(&scmd->eh_entry);
1597                 if (scsi_device_online(scmd->device) &&
1598                     !scsi_noretry_cmd(scmd) &&
1599                     (++scmd->retries <= scmd->allowed)) {
1600                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush"
1601                                                           " retry cmd: %p\n",
1602                                                           current->comm,
1603                                                           scmd));
1604                                 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
1605                 } else {
1606                         /*
1607                          * If just we got sense for the device (called
1608                          * scsi_eh_get_sense), scmd->result is already
1609                          * set, do not set DRIVER_TIMEOUT.
1610                          */
1611                         if (!scmd->result)
1612                                 scmd->result |= (DRIVER_TIMEOUT << 24);
1613                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush finish"
1614                                                         " cmd: %p\n",
1615                                                         current->comm, scmd));
1616                         scsi_finish_command(scmd);
1617                 }
1618         }
1619 }
1620 EXPORT_SYMBOL(scsi_eh_flush_done_q);
1621
1622 /**
1623  * scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
1624  * @shost:      Host to unjam.
1625  *
1626  * Notes:
1627  *    When we come in here, we *know* that all commands on the bus have
1628  *    either completed, failed or timed out.  we also know that no further
1629  *    commands are being sent to the host, so things are relatively quiet
1630  *    and we have freedom to fiddle with things as we wish.
1631  *
1632  *    This is only the *default* implementation.  it is possible for
1633  *    individual drivers to supply their own version of this function, and
1634  *    if the maintainer wishes to do this, it is strongly suggested that
1635  *    this function be taken as a template and modified.  this function
1636  *    was designed to correctly handle problems for about 95% of the
1637  *    different cases out there, and it should always provide at least a
1638  *    reasonable amount of error recovery.
1639  *
1640  *    Any command marked 'failed' or 'timeout' must eventually have
1641  *    scsi_finish_cmd() called for it.  we do all of the retry stuff
1642  *    here, so when we restart the host after we return it should have an
1643  *    empty queue.
1644  */
1645 static void scsi_unjam_host(struct Scsi_Host *shost)
1646 {
1647         unsigned long flags;
1648         LIST_HEAD(eh_work_q);
1649         LIST_HEAD(eh_done_q);
1650
1651         spin_lock_irqsave(shost->host_lock, flags);
1652         list_splice_init(&shost->eh_cmd_q, &eh_work_q);
1653         spin_unlock_irqrestore(shost->host_lock, flags);
1654
1655         SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
1656
1657         if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
1658                 if (!scsi_eh_abort_cmds(&eh_work_q, &eh_done_q))
1659                         scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
1660
1661         scsi_eh_flush_done_q(&eh_done_q);
1662 }
1663
1664 /**
1665  * scsi_error_handler - SCSI error handler thread
1666  * @data:       Host for which we are running.
1667  *
1668  * Notes:
1669  *    This is the main error handling loop.  This is run as a kernel thread
1670  *    for every SCSI host and handles all error handling activity.
1671  */
1672 int scsi_error_handler(void *data)
1673 {
1674         struct Scsi_Host *shost = data;
1675
1676         /*
1677          * We use TASK_INTERRUPTIBLE so that the thread is not
1678          * counted against the load average as a running process.
1679          * We never actually get interrupted because kthread_run
1680          * disables signal delivery for the created thread.
1681          */
1682         set_current_state(TASK_INTERRUPTIBLE);
1683         while (!kthread_should_stop()) {
1684                 if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||
1685                     shost->host_failed != shost->host_busy) {
1686                         SCSI_LOG_ERROR_RECOVERY(1,
1687                                 printk("Error handler scsi_eh_%d sleeping\n",
1688                                         shost->host_no));
1689                         schedule();
1690                         set_current_state(TASK_INTERRUPTIBLE);
1691                         continue;
1692                 }
1693
1694                 __set_current_state(TASK_RUNNING);
1695                 SCSI_LOG_ERROR_RECOVERY(1,
1696                         printk("Error handler scsi_eh_%d waking up\n",
1697                                 shost->host_no));
1698
1699                 /*
1700                  * We have a host that is failing for some reason.  Figure out
1701                  * what we need to do to get it up and online again (if we can).
1702                  * If we fail, we end up taking the thing offline.
1703                  */
1704                 if (shost->transportt->eh_strategy_handler)
1705                         shost->transportt->eh_strategy_handler(shost);
1706                 else
1707                         scsi_unjam_host(shost);
1708
1709                 /*
1710                  * Note - if the above fails completely, the action is to take
1711                  * individual devices offline and flush the queue of any
1712                  * outstanding requests that may have been pending.  When we
1713                  * restart, we restart any I/O to any other devices on the bus
1714                  * which are still online.
1715                  */
1716                 scsi_restart_operations(shost);
1717                 set_current_state(TASK_INTERRUPTIBLE);
1718         }
1719         __set_current_state(TASK_RUNNING);
1720
1721         SCSI_LOG_ERROR_RECOVERY(1,
1722                 printk("Error handler scsi_eh_%d exiting\n", shost->host_no));
1723         shost->ehandler = NULL;
1724         return 0;
1725 }
1726
1727 /*
1728  * Function:    scsi_report_bus_reset()
1729  *
1730  * Purpose:     Utility function used by low-level drivers to report that
1731  *              they have observed a bus reset on the bus being handled.
1732  *
1733  * Arguments:   shost       - Host in question
1734  *              channel     - channel on which reset was observed.
1735  *
1736  * Returns:     Nothing
1737  *
1738  * Lock status: Host lock must be held.
1739  *
1740  * Notes:       This only needs to be called if the reset is one which
1741  *              originates from an unknown location.  Resets originated
1742  *              by the mid-level itself don't need to call this, but there
1743  *              should be no harm.
1744  *
1745  *              The main purpose of this is to make sure that a CHECK_CONDITION
1746  *              is properly treated.
1747  */
1748 void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
1749 {
1750         struct scsi_device *sdev;
1751
1752         __shost_for_each_device(sdev, shost) {
1753                 if (channel == sdev_channel(sdev))
1754                         __scsi_report_device_reset(sdev, NULL);
1755         }
1756 }
1757 EXPORT_SYMBOL(scsi_report_bus_reset);
1758
1759 /*
1760  * Function:    scsi_report_device_reset()
1761  *
1762  * Purpose:     Utility function used by low-level drivers to report that
1763  *              they have observed a device reset on the device being handled.
1764  *
1765  * Arguments:   shost       - Host in question
1766  *              channel     - channel on which reset was observed
1767  *              target      - target on which reset was observed
1768  *
1769  * Returns:     Nothing
1770  *
1771  * Lock status: Host lock must be held
1772  *
1773  * Notes:       This only needs to be called if the reset is one which
1774  *              originates from an unknown location.  Resets originated
1775  *              by the mid-level itself don't need to call this, but there
1776  *              should be no harm.
1777  *
1778  *              The main purpose of this is to make sure that a CHECK_CONDITION
1779  *              is properly treated.
1780  */
1781 void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
1782 {
1783         struct scsi_device *sdev;
1784
1785         __shost_for_each_device(sdev, shost) {
1786                 if (channel == sdev_channel(sdev) &&
1787                     target == sdev_id(sdev))
1788                         __scsi_report_device_reset(sdev, NULL);
1789         }
1790 }
1791 EXPORT_SYMBOL(scsi_report_device_reset);
1792
1793 static void
1794 scsi_reset_provider_done_command(struct scsi_cmnd *scmd)
1795 {
1796 }
1797
1798 /*
1799  * Function:    scsi_reset_provider
1800  *
1801  * Purpose:     Send requested reset to a bus or device at any phase.
1802  *
1803  * Arguments:   device  - device to send reset to
1804  *              flag - reset type (see scsi.h)
1805  *
1806  * Returns:     SUCCESS/FAILURE.
1807  *
1808  * Notes:       This is used by the SCSI Generic driver to provide
1809  *              Bus/Device reset capability.
1810  */
1811 int
1812 scsi_reset_provider(struct scsi_device *dev, int flag)
1813 {
1814         struct scsi_cmnd *scmd = scsi_get_command(dev, GFP_KERNEL);
1815         struct Scsi_Host *shost = dev->host;
1816         struct request req;
1817         unsigned long flags;
1818         int rtn;
1819
1820         blk_rq_init(NULL, &req);
1821         scmd->request = &req;
1822
1823         scmd->cmnd = req.cmd;
1824
1825         scmd->scsi_done         = scsi_reset_provider_done_command;
1826         memset(&scmd->sdb, 0, sizeof(scmd->sdb));
1827
1828         scmd->cmd_len                   = 0;
1829
1830         scmd->sc_data_direction         = DMA_BIDIRECTIONAL;
1831
1832         spin_lock_irqsave(shost->host_lock, flags);
1833         shost->tmf_in_progress = 1;
1834         spin_unlock_irqrestore(shost->host_lock, flags);
1835
1836         switch (flag) {
1837         case SCSI_TRY_RESET_DEVICE:
1838                 rtn = scsi_try_bus_device_reset(scmd);
1839                 if (rtn == SUCCESS)
1840                         break;
1841                 /* FALLTHROUGH */
1842         case SCSI_TRY_RESET_TARGET:
1843                 rtn = scsi_try_target_reset(scmd);
1844                 if (rtn == SUCCESS)
1845                         break;
1846                 /* FALLTHROUGH */
1847         case SCSI_TRY_RESET_BUS:
1848                 rtn = scsi_try_bus_reset(scmd);
1849                 if (rtn == SUCCESS)
1850                         break;
1851                 /* FALLTHROUGH */
1852         case SCSI_TRY_RESET_HOST:
1853                 rtn = scsi_try_host_reset(scmd);
1854                 break;
1855         default:
1856                 rtn = FAILED;
1857         }
1858
1859         spin_lock_irqsave(shost->host_lock, flags);
1860         shost->tmf_in_progress = 0;
1861         spin_unlock_irqrestore(shost->host_lock, flags);
1862
1863         /*
1864          * be sure to wake up anyone who was sleeping or had their queue
1865          * suspended while we performed the TMF.
1866          */
1867         SCSI_LOG_ERROR_RECOVERY(3,
1868                 printk("%s: waking up host to restart after TMF\n",
1869                 __func__));
1870
1871         wake_up(&shost->host_wait);
1872
1873         scsi_run_host_queues(shost);
1874
1875         scsi_next_command(scmd);
1876         return rtn;
1877 }
1878 EXPORT_SYMBOL(scsi_reset_provider);
1879
1880 /**
1881  * scsi_normalize_sense - normalize main elements from either fixed or
1882  *                      descriptor sense data format into a common format.
1883  *
1884  * @sense_buffer:       byte array containing sense data returned by device
1885  * @sb_len:             number of valid bytes in sense_buffer
1886  * @sshdr:              pointer to instance of structure that common
1887  *                      elements are written to.
1888  *
1889  * Notes:
1890  *      The "main elements" from sense data are: response_code, sense_key,
1891  *      asc, ascq and additional_length (only for descriptor format).
1892  *
1893  *      Typically this function can be called after a device has
1894  *      responded to a SCSI command with the CHECK_CONDITION status.
1895  *
1896  * Return value:
1897  *      1 if valid sense data information found, else 0;
1898  */
1899 int scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
1900                          struct scsi_sense_hdr *sshdr)
1901 {
1902         if (!sense_buffer || !sb_len)
1903                 return 0;
1904
1905         memset(sshdr, 0, sizeof(struct scsi_sense_hdr));
1906
1907         sshdr->response_code = (sense_buffer[0] & 0x7f);
1908
1909         if (!scsi_sense_valid(sshdr))
1910                 return 0;
1911
1912         if (sshdr->response_code >= 0x72) {
1913                 /*
1914                  * descriptor format
1915                  */
1916                 if (sb_len > 1)
1917                         sshdr->sense_key = (sense_buffer[1] & 0xf);
1918                 if (sb_len > 2)
1919                         sshdr->asc = sense_buffer[2];
1920                 if (sb_len > 3)
1921                         sshdr->ascq = sense_buffer[3];
1922                 if (sb_len > 7)
1923                         sshdr->additional_length = sense_buffer[7];
1924         } else {
1925                 /*
1926                  * fixed format
1927                  */
1928                 if (sb_len > 2)
1929                         sshdr->sense_key = (sense_buffer[2] & 0xf);
1930                 if (sb_len > 7) {
1931                         sb_len = (sb_len < (sense_buffer[7] + 8)) ?
1932                                          sb_len : (sense_buffer[7] + 8);
1933                         if (sb_len > 12)
1934                                 sshdr->asc = sense_buffer[12];
1935                         if (sb_len > 13)
1936                                 sshdr->ascq = sense_buffer[13];
1937                 }
1938         }
1939
1940         return 1;
1941 }
1942 EXPORT_SYMBOL(scsi_normalize_sense);
1943
1944 int scsi_command_normalize_sense(struct scsi_cmnd *cmd,
1945                                  struct scsi_sense_hdr *sshdr)
1946 {
1947         return scsi_normalize_sense(cmd->sense_buffer,
1948                         SCSI_SENSE_BUFFERSIZE, sshdr);
1949 }
1950 EXPORT_SYMBOL(scsi_command_normalize_sense);
1951
1952 /**
1953  * scsi_sense_desc_find - search for a given descriptor type in descriptor sense data format.
1954  * @sense_buffer:       byte array of descriptor format sense data
1955  * @sb_len:             number of valid bytes in sense_buffer
1956  * @desc_type:          value of descriptor type to find
1957  *                      (e.g. 0 -> information)
1958  *
1959  * Notes:
1960  *      only valid when sense data is in descriptor format
1961  *
1962  * Return value:
1963  *      pointer to start of (first) descriptor if found else NULL
1964  */
1965 const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len,
1966                                 int desc_type)
1967 {
1968         int add_sen_len, add_len, desc_len, k;
1969         const u8 * descp;
1970
1971         if ((sb_len < 8) || (0 == (add_sen_len = sense_buffer[7])))
1972                 return NULL;
1973         if ((sense_buffer[0] < 0x72) || (sense_buffer[0] > 0x73))
1974                 return NULL;
1975         add_sen_len = (add_sen_len < (sb_len - 8)) ?
1976                         add_sen_len : (sb_len - 8);
1977         descp = &sense_buffer[8];
1978         for (desc_len = 0, k = 0; k < add_sen_len; k += desc_len) {
1979                 descp += desc_len;
1980                 add_len = (k < (add_sen_len - 1)) ? descp[1]: -1;
1981                 desc_len = add_len + 2;
1982                 if (descp[0] == desc_type)
1983                         return descp;
1984                 if (add_len < 0) // short descriptor ??
1985                         break;
1986         }
1987         return NULL;
1988 }
1989 EXPORT_SYMBOL(scsi_sense_desc_find);
1990
1991 /**
1992  * scsi_get_sense_info_fld - get information field from sense data (either fixed or descriptor format)
1993  * @sense_buffer:       byte array of sense data
1994  * @sb_len:             number of valid bytes in sense_buffer
1995  * @info_out:           pointer to 64 integer where 8 or 4 byte information
1996  *                      field will be placed if found.
1997  *
1998  * Return value:
1999  *      1 if information field found, 0 if not found.
2000  */
2001 int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
2002                             u64 * info_out)
2003 {
2004         int j;
2005         const u8 * ucp;
2006         u64 ull;
2007
2008         if (sb_len < 7)
2009                 return 0;
2010         switch (sense_buffer[0] & 0x7f) {
2011         case 0x70:
2012         case 0x71:
2013                 if (sense_buffer[0] & 0x80) {
2014                         *info_out = (sense_buffer[3] << 24) +
2015                                     (sense_buffer[4] << 16) +
2016                                     (sense_buffer[5] << 8) + sense_buffer[6];
2017                         return 1;
2018                 } else
2019                         return 0;
2020         case 0x72:
2021         case 0x73:
2022                 ucp = scsi_sense_desc_find(sense_buffer, sb_len,
2023                                            0 /* info desc */);
2024                 if (ucp && (0xa == ucp[1])) {
2025                         ull = 0;
2026                         for (j = 0; j < 8; ++j) {
2027                                 if (j > 0)
2028                                         ull <<= 8;
2029                                 ull |= ucp[4 + j];
2030                         }
2031                         *info_out = ull;
2032                         return 1;
2033                 } else
2034                         return 0;
2035         default:
2036                 return 0;
2037         }
2038 }
2039 EXPORT_SYMBOL(scsi_get_sense_info_fld);
2040
2041 /**
2042  * scsi_build_sense_buffer - build sense data in a buffer
2043  * @desc:       Sense format (non zero == descriptor format,
2044  *              0 == fixed format)
2045  * @buf:        Where to build sense data
2046  * @key:        Sense key
2047  * @asc:        Additional sense code
2048  * @ascq:       Additional sense code qualifier
2049  *
2050  **/
2051 void scsi_build_sense_buffer(int desc, u8 *buf, u8 key, u8 asc, u8 ascq)
2052 {
2053         if (desc) {
2054                 buf[0] = 0x72;  /* descriptor, current */
2055                 buf[1] = key;
2056                 buf[2] = asc;
2057                 buf[3] = ascq;
2058                 buf[7] = 0;
2059         } else {
2060                 buf[0] = 0x70;  /* fixed, current */
2061                 buf[2] = key;
2062                 buf[7] = 0xa;
2063                 buf[12] = asc;
2064                 buf[13] = ascq;
2065         }
2066 }
2067 EXPORT_SYMBOL(scsi_build_sense_buffer);