git.oblomov.eu Git - linux-2.6/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 /**
 335  * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD.
 336  * @scmd:       SCSI cmd to examine.
 337  *
 338  * Notes:
 339  *    This is *only* called when we are examining the status of commands
 340  *    queued during error recovery.  the main difference here is that we
 341  *    don't allow for the possibility of retries here, and we are a lot
 342  *    more restrictive about what we consider acceptable.
 343  */
 344 static int scsi_eh_completed_normally(struct scsi_cmnd *scmd)
 345 {
 346         /*
 347          * first check the host byte, to see if there is anything in there
 348          * that would indicate what we need to do.
 349          */
 350         if (host_byte(scmd->result) == DID_RESET) {
 351                 /*
 352                  * rats.  we are already in the error handler, so we now
 353                  * get to try and figure out what to do next.  if the sense
 354                  * is valid, we have a pretty good idea of what to do.
 355                  * if not, we mark it as FAILED.
 356                  */
 357                 return scsi_check_sense(scmd);
 358         }
 359         if (host_byte(scmd->result) != DID_OK)
 360                 return FAILED;
 361
 362         /*
 363          * next, check the message byte.
 364          */
 365         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
 366                 return FAILED;
 367
 368         /*
 369          * now, check the status byte to see if this indicates
 370          * anything special.
 371          */
 372         switch (status_byte(scmd->result)) {
 373         case GOOD:
 374         case COMMAND_TERMINATED:
 375                 return SUCCESS;
 376         case CHECK_CONDITION:
 377                 return scsi_check_sense(scmd);
 378         case CONDITION_GOOD:
 379         case INTERMEDIATE_GOOD:
 380         case INTERMEDIATE_C_GOOD:
 381                 /*
 382                  * who knows?  FIXME(eric)
 383                  */
 384                 return SUCCESS;
 385         case BUSY:
 386         case QUEUE_FULL:
 387         case RESERVATION_CONFLICT:
 388         default:
 389                 return FAILED;
 390         }
 391         return FAILED;
 392 }
 393
 394 /**
 395  * scsi_eh_done - Completion function for error handling.
 396  * @scmd:       Cmd that is done.
 397  */
 398 static void scsi_eh_done(struct scsi_cmnd *scmd)
 399 {
 400         struct completion     *eh_action;
 401
 402         SCSI_LOG_ERROR_RECOVERY(3,
 403                 printk("%s scmd: %p result: %x\n",
 404                         __func__, scmd, scmd->result));
 405
 406         eh_action = scmd->device->host->eh_action;
 407         if (eh_action)
 408                 complete(eh_action);
 409 }
 410
 411 /**
 412  * scsi_try_host_reset - ask host adapter to reset itself
 413  * @scmd:       SCSI cmd to send hsot reset.
 414  */
 415 static int scsi_try_host_reset(struct scsi_cmnd *scmd)
 416 {
 417         unsigned long flags;
 418         int rtn;
 419
 420         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Host RST\n",
 421                                           __func__));
 422
 423         if (!scmd->device->host->hostt->eh_host_reset_handler)
 424                 return FAILED;
 425
 426         rtn = scmd->device->host->hostt->eh_host_reset_handler(scmd);
 427
 428         if (rtn == SUCCESS) {
 429                 if (!scmd->device->host->hostt->skip_settle_delay)
 430                         ssleep(HOST_RESET_SETTLE_TIME);
 431                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
 432                 scsi_report_bus_reset(scmd->device->host,
 433                                       scmd_channel(scmd));
 434                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
 435         }
 436
 437         return rtn;
 438 }
 439
 440 /**
 441  * scsi_try_bus_reset - ask host to perform a bus reset
 442  * @scmd:       SCSI cmd to send bus reset.
 443  */
 444 static int scsi_try_bus_reset(struct scsi_cmnd *scmd)
 445 {
 446         unsigned long flags;
 447         int rtn;
 448
 449         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Bus RST\n",
 450                                           __func__));
 451
 452         if (!scmd->device->host->hostt->eh_bus_reset_handler)
 453                 return FAILED;
 454
 455         rtn = scmd->device->host->hostt->eh_bus_reset_handler(scmd);
 456
 457         if (rtn == SUCCESS) {
 458                 if (!scmd->device->host->hostt->skip_settle_delay)
 459                         ssleep(BUS_RESET_SETTLE_TIME);
 460                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
 461                 scsi_report_bus_reset(scmd->device->host,
 462                                       scmd_channel(scmd));
 463                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
 464         }
 465
 466         return rtn;
 467 }
 468
 469 static void __scsi_report_device_reset(struct scsi_device *sdev, void *data)
 470 {
 471         sdev->was_reset = 1;
 472         sdev->expecting_cc_ua = 1;
 473 }
 474
 475 /**
 476  * scsi_try_target_reset - Ask host to perform a target reset
 477  * @scmd:       SCSI cmd used to send a target reset
 478  *
 479  * Notes:
 480  *    There is no timeout for this operation.  if this operation is
 481  *    unreliable for a given host, then the host itself needs to put a
 482  *    timer on it, and set the host back to a consistent state prior to
 483  *    returning.
 484  */
 485 static int scsi_try_target_reset(struct scsi_cmnd *scmd)
 486 {
 487         unsigned long flags;
 488         int rtn;
 489
 490         if (!scmd->device->host->hostt->eh_target_reset_handler)
 491                 return FAILED;
 492
 493         rtn = scmd->device->host->hostt->eh_target_reset_handler(scmd);
 494         if (rtn == SUCCESS) {
 495                 spin_lock_irqsave(scmd->device->host->host_lock, flags);
 496                 __starget_for_each_device(scsi_target(scmd->device), NULL,
 497                                           __scsi_report_device_reset);
 498                 spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
 499         }
 500
 501         return rtn;
 502 }
 503
 504 /**
 505  * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
 506  * @scmd:       SCSI cmd used to send BDR
 507  *
 508  * Notes:
 509  *    There is no timeout for this operation.  if this operation is
 510  *    unreliable for a given host, then the host itself needs to put a
 511  *    timer on it, and set the host back to a consistent state prior to
 512  *    returning.
 513  */
 514 static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
 515 {
 516         int rtn;
 517
 518         if (!scmd->device->host->hostt->eh_device_reset_handler)
 519                 return FAILED;
 520
 521         rtn = scmd->device->host->hostt->eh_device_reset_handler(scmd);
 522         if (rtn == SUCCESS)
 523                 __scsi_report_device_reset(scmd->device, NULL);
 524         return rtn;
 525 }
 526
 527 static int __scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
 528 {
 529         if (!scmd->device->host->hostt->eh_abort_handler)
 530                 return FAILED;
 531
 532         return scmd->device->host->hostt->eh_abort_handler(scmd);
 533 }
 534
 535 /**
 536  * scsi_try_to_abort_cmd - Ask host to abort a running command.
 537  * @scmd:       SCSI cmd to abort from Lower Level.
 538  *
 539  * Notes:
 540  *    This function will not return until the user's completion function
 541  *    has been called.  there is no timeout on this operation.  if the
 542  *    author of the low-level driver wishes this operation to be timed,
 543  *    they can provide this facility themselves.  helper functions in
 544  *    scsi_error.c can be supplied to make this easier to do.
 545  */
 546 static int scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
 547 {
 548         /*
 549          * scsi_done was called just after the command timed out and before
 550          * we had a chance to process it. (db)
 551          */
 552         if (scmd->serial_number == 0)
 553                 return SUCCESS;
 554         return __scsi_try_to_abort_cmd(scmd);
 555 }
 556
 557 static void scsi_abort_eh_cmnd(struct scsi_cmnd *scmd)
 558 {
 559         if (__scsi_try_to_abort_cmd(scmd) != SUCCESS)
 560                 if (scsi_try_bus_device_reset(scmd) != SUCCESS)
 561                         if (scsi_try_target_reset(scmd) != SUCCESS)
 562                                 if (scsi_try_bus_reset(scmd) != SUCCESS)
 563                                         scsi_try_host_reset(scmd);
 564 }
 565
 566 /**
 567  * scsi_eh_prep_cmnd  - Save a scsi command info as part of error recory
 568  * @scmd:       SCSI command structure to hijack
 569  * @ses:        structure to save restore information
 570  * @cmnd:       CDB to send. Can be NULL if no new cmnd is needed
 571  * @cmnd_size:  size in bytes of @cmnd (must be <= BLK_MAX_CDB)
 572  * @sense_bytes: size of sense data to copy. or 0 (if != 0 @cmnd is ignored)
 573  *
 574  * This function is used to save a scsi command information before re-execution
 575  * as part of the error recovery process.  If @sense_bytes is 0 the command
 576  * sent must be one that does not transfer any data.  If @sense_bytes != 0
 577  * @cmnd is ignored and this functions sets up a REQUEST_SENSE command
 578  * and cmnd buffers to read @sense_bytes into @scmd->sense_buffer.
 579  */
 580 void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses,
 581                         unsigned char *cmnd, int cmnd_size, unsigned sense_bytes)
 582 {
 583         struct scsi_device *sdev = scmd->device;
 584
 585         /*
 586          * We need saved copies of a number of fields - this is because
 587          * error handling may need to overwrite these with different values
 588          * to run different commands, and once error handling is complete,
 589          * we will need to restore these values prior to running the actual
 590          * command.
 591          */
 592         ses->cmd_len = scmd->cmd_len;
 593         ses->cmnd = scmd->cmnd;
 594         ses->data_direction = scmd->sc_data_direction;
 595         ses->sdb = scmd->sdb;
 596         ses->next_rq = scmd->request->next_rq;
 597         ses->result = scmd->result;
 598         ses->underflow = scmd->underflow;
 599         ses->prot_op = scmd->prot_op;
 600
 601         scmd->prot_op = SCSI_PROT_NORMAL;
 602         scmd->cmnd = ses->eh_cmnd;
 603         memset(scmd->cmnd, 0, BLK_MAX_CDB);
 604         memset(&scmd->sdb, 0, sizeof(scmd->sdb));
 605         scmd->request->next_rq = NULL;
 606
 607         if (sense_bytes) {
 608                 scmd->sdb.length = min_t(unsigned, SCSI_SENSE_BUFFERSIZE,
 609                                          sense_bytes);
 610                 sg_init_one(&ses->sense_sgl, scmd->sense_buffer,
 611                             scmd->sdb.length);
 612                 scmd->sdb.table.sgl = &ses->sense_sgl;
 613                 scmd->sc_data_direction = DMA_FROM_DEVICE;
 614                 scmd->sdb.table.nents = 1;
 615                 scmd->cmnd[0] = REQUEST_SENSE;
 616                 scmd->cmnd[4] = scmd->sdb.length;
 617                 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
 618         } else {
 619                 scmd->sc_data_direction = DMA_NONE;
 620                 if (cmnd) {
 621                         BUG_ON(cmnd_size > BLK_MAX_CDB);
 622                         memcpy(scmd->cmnd, cmnd, cmnd_size);
 623                         scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
 624                 }
 625         }
 626
 627         scmd->underflow = 0;
 628
 629         if (sdev->scsi_level <= SCSI_2 && sdev->scsi_level != SCSI_UNKNOWN)
 630                 scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
 631                         (sdev->lun << 5 & 0xe0);
 632
 633         /*
 634          * Zero the sense buffer.  The scsi spec mandates that any
 635          * untransferred sense data should be interpreted as being zero.
 636          */
 637         memset(scmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
 638 }
 639 EXPORT_SYMBOL(scsi_eh_prep_cmnd);
 640
 641 /**
 642  * scsi_eh_restore_cmnd  - Restore a scsi command info as part of error recory
 643  * @scmd:       SCSI command structure to restore
 644  * @ses:        saved information from a coresponding call to scsi_prep_eh_cmnd
 645  *
 646  * Undo any damage done by above scsi_prep_eh_cmnd().
 647  */
 648 void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct scsi_eh_save *ses)
 649 {
 650         /*
 651          * Restore original data
 652          */
 653         scmd->cmd_len = ses->cmd_len;
 654         scmd->cmnd = ses->cmnd;
 655         scmd->sc_data_direction = ses->data_direction;
 656         scmd->sdb = ses->sdb;
 657         scmd->request->next_rq = ses->next_rq;
 658         scmd->result = ses->result;
 659         scmd->underflow = ses->underflow;
 660         scmd->prot_op = ses->prot_op;
 661 }
 662 EXPORT_SYMBOL(scsi_eh_restore_cmnd);
 663
 664 /**
 665  * scsi_send_eh_cmnd  - submit a scsi command as part of error recory
 666  * @scmd:       SCSI command structure to hijack
 667  * @cmnd:       CDB to send
 668  * @cmnd_size:  size in bytes of @cmnd
 669  * @timeout:    timeout for this request
 670  * @sense_bytes: size of sense data to copy or 0
 671  *
 672  * This function is used to send a scsi command down to a target device
 673  * as part of the error recovery process. See also scsi_eh_prep_cmnd() above.
 674  *
 675  * Return value:
 676  *    SUCCESS or FAILED or NEEDS_RETRY
 677  */
 678 static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd,
 679                              int cmnd_size, int timeout, unsigned sense_bytes)
 680 {
 681         struct scsi_device *sdev = scmd->device;
 682         struct Scsi_Host *shost = sdev->host;
 683         DECLARE_COMPLETION_ONSTACK(done);
 684         unsigned long timeleft;
 685         unsigned long flags;
 686         struct scsi_eh_save ses;
 687         int rtn;
 688
 689         scsi_eh_prep_cmnd(scmd, &ses, cmnd, cmnd_size, sense_bytes);
 690         shost->eh_action = &done;
 691
 692         spin_lock_irqsave(shost->host_lock, flags);
 693         scsi_log_send(scmd);
 694         shost->hostt->queuecommand(scmd, scsi_eh_done);
 695         spin_unlock_irqrestore(shost->host_lock, flags);
 696
 697         timeleft = wait_for_completion_timeout(&done, timeout);
 698
 699         shost->eh_action = NULL;
 700
 701         scsi_log_completion(scmd, SUCCESS);
 702
 703         SCSI_LOG_ERROR_RECOVERY(3,
 704                 printk("%s: scmd: %p, timeleft: %ld\n",
 705                         __func__, scmd, timeleft));
 706
 707         /*
 708          * If there is time left scsi_eh_done got called, and we will
 709          * examine the actual status codes to see whether the command
 710          * actually did complete normally, else tell the host to forget
 711          * about this command.
 712          */
 713         if (timeleft) {
 714                 rtn = scsi_eh_completed_normally(scmd);
 715                 SCSI_LOG_ERROR_RECOVERY(3,
 716                         printk("%s: scsi_eh_completed_normally %x\n",
 717                                __func__, rtn));
 718
 719                 switch (rtn) {
 720                 case SUCCESS:
 721                 case NEEDS_RETRY:
 722                 case FAILED:
 723                         break;
 724                 default:
 725                         rtn = FAILED;
 726                         break;
 727                 }
 728         } else {
 729                 scsi_abort_eh_cmnd(scmd);
 730                 rtn = FAILED;
 731         }
 732
 733         scsi_eh_restore_cmnd(scmd, &ses);
 734         return rtn;
 735 }
 736
 737 /**
 738  * scsi_request_sense - Request sense data from a particular target.
 739  * @scmd:       SCSI cmd for request sense.
 740  *
 741  * Notes:
 742  *    Some hosts automatically obtain this information, others require
 743  *    that we obtain it on our own. This function will *not* return until
 744  *    the command either times out, or it completes.
 745  */
 746 static int scsi_request_sense(struct scsi_cmnd *scmd)
 747 {
 748         return scsi_send_eh_cmnd(scmd, NULL, 0, SENSE_TIMEOUT, ~0);
 749 }
 750
 751 /**
 752  * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
 753  * @scmd:       Original SCSI cmd that eh has finished.
 754  * @done_q:     Queue for processed commands.
 755  *
 756  * Notes:
 757  *    We don't want to use the normal command completion while we are are
 758  *    still handling errors - it may cause other commands to be queued,
 759  *    and that would disturb what we are doing.  Thus we really want to
 760  *    keep a list of pending commands for final completion, and once we
 761  *    are ready to leave error handling we handle completion for real.
 762  */
 763 void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)
 764 {
 765         scmd->device->host->host_failed--;
 766         scmd->eh_eflags = 0;
 767         list_move_tail(&scmd->eh_entry, done_q);
 768 }
 769 EXPORT_SYMBOL(scsi_eh_finish_cmd);
 770
 771 /**
 772  * scsi_eh_get_sense - Get device sense data.
 773  * @work_q:     Queue of commands to process.
 774  * @done_q:     Queue of processed commands.
 775  *
 776  * Description:
 777  *    See if we need to request sense information.  if so, then get it
 778  *    now, so we have a better idea of what to do.
 779  *
 780  * Notes:
 781  *    This has the unfortunate side effect that if a shost adapter does
 782  *    not automatically request sense information, we end up shutting
 783  *    it down before we request it.
 784  *
 785  *    All drivers should request sense information internally these days,
 786  *    so for now all I have to say is tough noogies if you end up in here.
 787  *
 788  *    XXX: Long term this code should go away, but that needs an audit of
 789  *         all LLDDs first.
 790  */
 791 int scsi_eh_get_sense(struct list_head *work_q,
 792                       struct list_head *done_q)
 793 {
 794         struct scsi_cmnd *scmd, *next;
 795         int rtn;
 796
 797         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
 798                 if ((scmd->eh_eflags & SCSI_EH_CANCEL_CMD) ||
 799                     SCSI_SENSE_VALID(scmd))
 800                         continue;
 801
 802                 SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd,
 803                                                   "%s: requesting sense\n",
 804                                                   current->comm));
 805                 rtn = scsi_request_sense(scmd);
 806                 if (rtn != SUCCESS)
 807                         continue;
 808
 809                 SCSI_LOG_ERROR_RECOVERY(3, printk("sense requested for %p"
 810                                                   " result %x\n", scmd,
 811                                                   scmd->result));
 812                 SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense("bh", scmd));
 813
 814                 rtn = scsi_decide_disposition(scmd);
 815
 816                 /*
 817                  * if the result was normal, then just pass it along to the
 818                  * upper level.
 819                  */
 820                 if (rtn == SUCCESS)
 821                         /* we don't want this command reissued, just
 822                          * finished with the sense data, so set
 823                          * retries to the max allowed to ensure it
 824                          * won't get reissued */
 825                         scmd->retries = scmd->allowed;
 826                 else if (rtn != NEEDS_RETRY)
 827                         continue;
 828
 829                 scsi_eh_finish_cmd(scmd, done_q);
 830         }
 831
 832         return list_empty(work_q);
 833 }
 834 EXPORT_SYMBOL_GPL(scsi_eh_get_sense);
 835
 836 /**
 837  * scsi_eh_tur - Send TUR to device.
 838  * @scmd:       &scsi_cmnd to send TUR
 839  *
 840  * Return value:
 841  *    0 - Device is ready. 1 - Device NOT ready.
 842  */
 843 static int scsi_eh_tur(struct scsi_cmnd *scmd)
 844 {
 845         static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
 846         int retry_cnt = 1, rtn;
 847
 848 retry_tur:
 849         rtn = scsi_send_eh_cmnd(scmd, tur_command, 6, SENSE_TIMEOUT, 0);
 850
 851         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
 852                 __func__, scmd, rtn));
 853
 854         switch (rtn) {
 855         case NEEDS_RETRY:
 856                 if (retry_cnt--)
 857                         goto retry_tur;
 858                 /*FALLTHRU*/
 859         case SUCCESS:
 860                 return 0;
 861         default:
 862                 return 1;
 863         }
 864 }
 865
 866 /**
 867  * scsi_eh_abort_cmds - abort pending commands.
 868  * @work_q:     &list_head for pending commands.
 869  * @done_q:     &list_head for processed commands.
 870  *
 871  * Decription:
 872  *    Try and see whether or not it makes sense to try and abort the
 873  *    running command.  This only works out to be the case if we have one
 874  *    command that has timed out.  If the command simply failed, it makes
 875  *    no sense to try and abort the command, since as far as the shost
 876  *    adapter is concerned, it isn't running.
 877  */
 878 static int scsi_eh_abort_cmds(struct list_head *work_q,
 879                               struct list_head *done_q)
 880 {
 881         struct scsi_cmnd *scmd, *next;
 882         int rtn;
 883
 884         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
 885                 if (!(scmd->eh_eflags & SCSI_EH_CANCEL_CMD))
 886                         continue;
 887                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting cmd:"
 888                                                   "0x%p\n", current->comm,
 889                                                   scmd));
 890                 rtn = scsi_try_to_abort_cmd(scmd);
 891                 if (rtn == SUCCESS) {
 892                         scmd->eh_eflags &= ~SCSI_EH_CANCEL_CMD;
 893                         if (!scsi_device_online(scmd->device) ||
 894                             !scsi_eh_tur(scmd)) {
 895                                 scsi_eh_finish_cmd(scmd, done_q);
 896                         }
 897
 898                 } else
 899                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting"
 900                                                           " cmd failed:"
 901                                                           "0x%p\n",
 902                                                           current->comm,
 903                                                           scmd));
 904         }
 905
 906         return list_empty(work_q);
 907 }
 908
 909 /**
 910  * scsi_eh_try_stu - Send START_UNIT to device.
 911  * @scmd:       &scsi_cmnd to send START_UNIT
 912  *
 913  * Return value:
 914  *    0 - Device is ready. 1 - Device NOT ready.
 915  */
 916 static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
 917 {
 918         static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
 919
 920         if (scmd->device->allow_restart) {
 921                 int i, rtn = NEEDS_RETRY;
 922
 923                 for (i = 0; rtn == NEEDS_RETRY && i < 2; i++)
 924                         rtn = scsi_send_eh_cmnd(scmd, stu_command, 6, scmd->device->request_queue->rq_timeout, 0);
 925
 926                 if (rtn == SUCCESS)
 927                         return 0;
 928         }
 929
 930         return 1;
 931 }
 932
 933  /**
 934  * scsi_eh_stu - send START_UNIT if needed
 935  * @shost:      &scsi host being recovered.
 936  * @work_q:     &list_head for pending commands.
 937  * @done_q:     &list_head for processed commands.
 938  *
 939  * Notes:
 940  *    If commands are failing due to not ready, initializing command required,
 941  *      try revalidating the device, which will end up sending a start unit.
 942  */
 943 static int scsi_eh_stu(struct Scsi_Host *shost,
 944                               struct list_head *work_q,
 945                               struct list_head *done_q)
 946 {
 947         struct scsi_cmnd *scmd, *stu_scmd, *next;
 948         struct scsi_device *sdev;
 949
 950         shost_for_each_device(sdev, shost) {
 951                 stu_scmd = NULL;
 952                 list_for_each_entry(scmd, work_q, eh_entry)
 953                         if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
 954                             scsi_check_sense(scmd) == FAILED ) {
 955                                 stu_scmd = scmd;
 956                                 break;
 957                         }
 958
 959                 if (!stu_scmd)
 960                         continue;
 961
 962                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending START_UNIT to sdev:"
 963                                                   " 0x%p\n", current->comm, sdev));
 964
 965                 if (!scsi_eh_try_stu(stu_scmd)) {
 966                         if (!scsi_device_online(sdev) ||
 967                             !scsi_eh_tur(stu_scmd)) {
 968                                 list_for_each_entry_safe(scmd, next,
 969                                                           work_q, eh_entry) {
 970                                         if (scmd->device == sdev)
 971                                                 scsi_eh_finish_cmd(scmd, done_q);
 972                                 }
 973                         }
 974                 } else {
 975                         SCSI_LOG_ERROR_RECOVERY(3,
 976                                                 printk("%s: START_UNIT failed to sdev:"
 977                                                        " 0x%p\n", current->comm, sdev));
 978                 }
 979         }
 980
 981         return list_empty(work_q);
 982 }
 983
 984
 985 /**
 986  * scsi_eh_bus_device_reset - send bdr if needed
 987  * @shost:      scsi host being recovered.
 988  * @work_q:     &list_head for pending commands.
 989  * @done_q:     &list_head for processed commands.
 990  *
 991  * Notes:
 992  *    Try a bus device reset.  Still, look to see whether we have multiple
 993  *    devices that are jammed or not - if we have multiple devices, it
 994  *    makes no sense to try bus_device_reset - we really would need to try
 995  *    a bus_reset instead.
 996  */
 997 static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
 998                                     struct list_head *work_q,
 999                                     struct list_head *done_q)
1000 {
1001         struct scsi_cmnd *scmd, *bdr_scmd, *next;
1002         struct scsi_device *sdev;
1003         int rtn;
1004
1005         shost_for_each_device(sdev, shost) {
1006                 bdr_scmd = NULL;
1007                 list_for_each_entry(scmd, work_q, eh_entry)
1008                         if (scmd->device == sdev) {
1009                                 bdr_scmd = scmd;
1010                                 break;
1011                         }
1012
1013                 if (!bdr_scmd)
1014                         continue;
1015
1016                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BDR sdev:"
1017                                                   " 0x%p\n", current->comm,
1018                                                   sdev));
1019                 rtn = scsi_try_bus_device_reset(bdr_scmd);
1020                 if (rtn == SUCCESS) {
1021                         if (!scsi_device_online(sdev) ||
1022                             !scsi_eh_tur(bdr_scmd)) {
1023                                 list_for_each_entry_safe(scmd, next,
1024                                                          work_q, eh_entry) {
1025                                         if (scmd->device == sdev)
1026                                                 scsi_eh_finish_cmd(scmd,
1027                                                                    done_q);
1028                                 }
1029                         }
1030                 } else {
1031                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BDR"
1032                                                           " failed sdev:"
1033                                                           "0x%p\n",
1034                                                           current->comm,
1035                                                            sdev));
1036                 }
1037         }
1038
1039         return list_empty(work_q);
1040 }
1041
1042 /**
1043  * scsi_eh_target_reset - send target reset if needed
1044  * @shost:      scsi host being recovered.
1045  * @work_q:     &list_head for pending commands.
1046  * @done_q:     &list_head for processed commands.
1047  *
1048  * Notes:
1049  *    Try a target reset.
1050  */
1051 static int scsi_eh_target_reset(struct Scsi_Host *shost,
1052                                 struct list_head *work_q,
1053                                 struct list_head *done_q)
1054 {
1055         struct scsi_cmnd *scmd, *tgtr_scmd, *next;
1056         unsigned int id = 0;
1057         int rtn;
1058
1059         do {
1060                 tgtr_scmd = NULL;
1061                 list_for_each_entry(scmd, work_q, eh_entry) {
1062                         if (id == scmd_id(scmd)) {
1063                                 tgtr_scmd = scmd;
1064                                 break;
1065                         }
1066                 }
1067                 if (!tgtr_scmd) {
1068                         /* not one exactly equal; find the next highest */
1069                         list_for_each_entry(scmd, work_q, eh_entry) {
1070                                 if (scmd_id(scmd) > id &&
1071                                     (!tgtr_scmd ||
1072                                      scmd_id(tgtr_scmd) > scmd_id(scmd)))
1073                                                 tgtr_scmd = scmd;
1074                         }
1075                 }
1076                 if (!tgtr_scmd)
1077                         /* no more commands, that's it */
1078                         break;
1079
1080                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending target reset "
1081                                                   "to target %d\n",
1082                                                   current->comm, id));
1083                 rtn = scsi_try_target_reset(tgtr_scmd);
1084                 if (rtn == SUCCESS) {
1085                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1086                                 if (id == scmd_id(scmd))
1087                                         if (!scsi_device_online(scmd->device) ||
1088                                             !scsi_eh_tur(tgtr_scmd))
1089                                                 scsi_eh_finish_cmd(scmd,
1090                                                                    done_q);
1091                         }
1092                 } else
1093                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Target reset"
1094                                                           " failed target: "
1095                                                           "%d\n",
1096                                                           current->comm, id));
1097                 id++;
1098         } while(id != 0);
1099
1100         return list_empty(work_q);
1101 }
1102
1103 /**
1104  * scsi_eh_bus_reset - send a bus reset
1105  * @shost:      &scsi host being recovered.
1106  * @work_q:     &list_head for pending commands.
1107  * @done_q:     &list_head for processed commands.
1108  */
1109 static int scsi_eh_bus_reset(struct Scsi_Host *shost,
1110                              struct list_head *work_q,
1111                              struct list_head *done_q)
1112 {
1113         struct scsi_cmnd *scmd, *chan_scmd, *next;
1114         unsigned int channel;
1115         int rtn;
1116
1117         /*
1118          * we really want to loop over the various channels, and do this on
1119          * a channel by channel basis.  we should also check to see if any
1120          * of the failed commands are on soft_reset devices, and if so, skip
1121          * the reset.
1122          */
1123
1124         for (channel = 0; channel <= shost->max_channel; channel++) {
1125                 chan_scmd = NULL;
1126                 list_for_each_entry(scmd, work_q, eh_entry) {
1127                         if (channel == scmd_channel(scmd)) {
1128                                 chan_scmd = scmd;
1129                                 break;
1130                                 /*
1131                                  * FIXME add back in some support for
1132                                  * soft_reset devices.
1133                                  */
1134                         }
1135                 }
1136
1137                 if (!chan_scmd)
1138                         continue;
1139                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BRST chan:"
1140                                                   " %d\n", current->comm,
1141                                                   channel));
1142                 rtn = scsi_try_bus_reset(chan_scmd);
1143                 if (rtn == SUCCESS) {
1144                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1145                                 if (channel == scmd_channel(scmd))
1146                                         if (!scsi_device_online(scmd->device) ||
1147                                             !scsi_eh_tur(scmd))
1148                                                 scsi_eh_finish_cmd(scmd,
1149                                                                    done_q);
1150                         }
1151                 } else {
1152                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BRST"
1153                                                           " failed chan: %d\n",
1154                                                           current->comm,
1155                                                           channel));
1156                 }
1157         }
1158         return list_empty(work_q);
1159 }
1160
1161 /**
1162  * scsi_eh_host_reset - send a host reset
1163  * @work_q:     list_head for processed commands.
1164  * @done_q:     list_head for processed commands.
1165  */
1166 static int scsi_eh_host_reset(struct list_head *work_q,
1167                               struct list_head *done_q)
1168 {
1169         struct scsi_cmnd *scmd, *next;
1170         int rtn;
1171
1172         if (!list_empty(work_q)) {
1173                 scmd = list_entry(work_q->next,
1174                                   struct scsi_cmnd, eh_entry);
1175
1176                 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending HRST\n"
1177                                                   , current->comm));
1178
1179                 rtn = scsi_try_host_reset(scmd);
1180                 if (rtn == SUCCESS) {
1181                         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1182                                 if (!scsi_device_online(scmd->device) ||
1183                                     (!scsi_eh_try_stu(scmd) && !scsi_eh_tur(scmd)) ||
1184                                     !scsi_eh_tur(scmd))
1185                                         scsi_eh_finish_cmd(scmd, done_q);
1186                         }
1187                 } else {
1188                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: HRST"
1189                                                           " failed\n",
1190                                                           current->comm));
1191                 }
1192         }
1193         return list_empty(work_q);
1194 }
1195
1196 /**
1197  * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
1198  * @work_q:     list_head for processed commands.
1199  * @done_q:     list_head for processed commands.
1200  */
1201 static void scsi_eh_offline_sdevs(struct list_head *work_q,
1202                                   struct list_head *done_q)
1203 {
1204         struct scsi_cmnd *scmd, *next;
1205
1206         list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1207                 sdev_printk(KERN_INFO, scmd->device, "Device offlined - "
1208                             "not ready after error recovery\n");
1209                 scsi_device_set_state(scmd->device, SDEV_OFFLINE);
1210                 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD) {
1211                         /*
1212                          * FIXME: Handle lost cmds.
1213                          */
1214                 }
1215                 scsi_eh_finish_cmd(scmd, done_q);
1216         }
1217         return;
1218 }
1219
1220 /**
1221  * scsi_noretry_cmd - determinte if command should be failed fast
1222  * @scmd:       SCSI cmd to examine.
1223  */
1224 int scsi_noretry_cmd(struct scsi_cmnd *scmd)
1225 {
1226         switch (host_byte(scmd->result)) {
1227         case DID_OK:
1228                 break;
1229         case DID_BUS_BUSY:
1230                 return blk_failfast_transport(scmd->request);
1231         case DID_PARITY:
1232                 return blk_failfast_dev(scmd->request);
1233         case DID_ERROR:
1234                 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1235                     status_byte(scmd->result) == RESERVATION_CONFLICT)
1236                         return 0;
1237                 /* fall through */
1238         case DID_SOFT_ERROR:
1239                 return blk_failfast_driver(scmd->request);
1240         }
1241
1242         switch (status_byte(scmd->result)) {
1243         case CHECK_CONDITION:
1244                 /*
1245                  * assume caller has checked sense and determinted
1246                  * the check condition was retryable.
1247                  */
1248                 return blk_failfast_dev(scmd->request);
1249         }
1250
1251         return 0;
1252 }
1253
1254 /**
1255  * scsi_decide_disposition - Disposition a cmd on return from LLD.
1256  * @scmd:       SCSI cmd to examine.
1257  *
1258  * Notes:
1259  *    This is *only* called when we are examining the status after sending
1260  *    out the actual data command.  any commands that are queued for error
1261  *    recovery (e.g. test_unit_ready) do *not* come through here.
1262  *
1263  *    When this routine returns failed, it means the error handler thread
1264  *    is woken.  In cases where the error code indicates an error that
1265  *    doesn't require the error handler read (i.e. we don't need to
1266  *    abort/reset), this function should return SUCCESS.
1267  */
1268 int scsi_decide_disposition(struct scsi_cmnd *scmd)
1269 {
1270         int rtn;
1271
1272         /*
1273          * if the device is offline, then we clearly just pass the result back
1274          * up to the top level.
1275          */
1276         if (!scsi_device_online(scmd->device)) {
1277                 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: device offline - report"
1278                                                   " as SUCCESS\n",
1279                                                   __func__));
1280                 return SUCCESS;
1281         }
1282
1283         /*
1284          * first check the host byte, to see if there is anything in there
1285          * that would indicate what we need to do.
1286          */
1287         switch (host_byte(scmd->result)) {
1288         case DID_PASSTHROUGH:
1289                 /*
1290                  * no matter what, pass this through to the upper layer.
1291                  * nuke this special code so that it looks like we are saying
1292                  * did_ok.
1293                  */
1294                 scmd->result &= 0xff00ffff;
1295                 return SUCCESS;
1296         case DID_OK:
1297                 /*
1298                  * looks good.  drop through, and check the next byte.
1299                  */
1300                 break;
1301         case DID_NO_CONNECT:
1302         case DID_BAD_TARGET:
1303         case DID_ABORT:
1304                 /*
1305                  * note - this means that we just report the status back
1306                  * to the top level driver, not that we actually think
1307                  * that it indicates SUCCESS.
1308                  */
1309                 return SUCCESS;
1310                 /*
1311                  * when the low level driver returns did_soft_error,
1312                  * it is responsible for keeping an internal retry counter
1313                  * in order to avoid endless loops (db)
1314                  *
1315                  * actually this is a bug in this function here.  we should
1316                  * be mindful of the maximum number of retries specified
1317                  * and not get stuck in a loop.
1318                  */
1319         case DID_SOFT_ERROR:
1320                 goto maybe_retry;
1321         case DID_IMM_RETRY:
1322                 return NEEDS_RETRY;
1323
1324         case DID_REQUEUE:
1325                 return ADD_TO_MLQUEUE;
1326         case DID_TRANSPORT_DISRUPTED:
1327                 /*
1328                  * LLD/transport was disrupted during processing of the IO.
1329                  * The transport class is now blocked/blocking,
1330                  * and the transport will decide what to do with the IO
1331                  * based on its timers and recovery capablilities if
1332                  * there are enough retries.
1333                  */
1334                 goto maybe_retry;
1335         case DID_TRANSPORT_FAILFAST:
1336                 /*
1337                  * The transport decided to failfast the IO (most likely
1338                  * the fast io fail tmo fired), so send IO directly upwards.
1339                  */
1340                 return SUCCESS;
1341         case DID_ERROR:
1342                 if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1343                     status_byte(scmd->result) == RESERVATION_CONFLICT)
1344                         /*
1345                          * execute reservation conflict processing code
1346                          * lower down
1347                          */
1348                         break;
1349                 /* fallthrough */
1350
1351         case DID_BUS_BUSY:
1352         case DID_PARITY:
1353                 goto maybe_retry;
1354         case DID_TIME_OUT:
1355                 /*
1356                  * when we scan the bus, we get timeout messages for
1357                  * these commands if there is no device available.
1358                  * other hosts report did_no_connect for the same thing.
1359                  */
1360                 if ((scmd->cmnd[0] == TEST_UNIT_READY ||
1361                      scmd->cmnd[0] == INQUIRY)) {
1362                         return SUCCESS;
1363                 } else {
1364                         return FAILED;
1365                 }
1366         case DID_RESET:
1367                 return SUCCESS;
1368         default:
1369                 return FAILED;
1370         }
1371
1372         /*
1373          * next, check the message byte.
1374          */
1375         if (msg_byte(scmd->result) != COMMAND_COMPLETE)
1376                 return FAILED;
1377
1378         /*
1379          * check the status byte to see if this indicates anything special.
1380          */
1381         switch (status_byte(scmd->result)) {
1382         case QUEUE_FULL:
1383                 /*
1384                  * the case of trying to send too many commands to a
1385                  * tagged queueing device.
1386                  */
1387         case BUSY:
1388                 /*
1389                  * device can't talk to us at the moment.  Should only
1390                  * occur (SAM-3) when the task queue is empty, so will cause
1391                  * the empty queue handling to trigger a stall in the
1392                  * device.
1393                  */
1394                 return ADD_TO_MLQUEUE;
1395         case GOOD:
1396         case COMMAND_TERMINATED:
1397                 return SUCCESS;
1398         case TASK_ABORTED:
1399                 goto maybe_retry;
1400         case CHECK_CONDITION:
1401                 rtn = scsi_check_sense(scmd);
1402                 if (rtn == NEEDS_RETRY)
1403                         goto maybe_retry;
1404                 /* if rtn == FAILED, we have no sense information;
1405                  * returning FAILED will wake the error handler thread
1406                  * to collect the sense and redo the decide
1407                  * disposition */
1408                 return rtn;
1409         case CONDITION_GOOD:
1410         case INTERMEDIATE_GOOD:
1411         case INTERMEDIATE_C_GOOD:
1412         case ACA_ACTIVE:
1413                 /*
1414                  * who knows?  FIXME(eric)
1415                  */
1416                 return SUCCESS;
1417
1418         case RESERVATION_CONFLICT:
1419                 sdev_printk(KERN_INFO, scmd->device,
1420                             "reservation conflict\n");
1421                 return SUCCESS; /* causes immediate i/o error */
1422         default:
1423                 return FAILED;
1424         }
1425         return FAILED;
1426
1427       maybe_retry:
1428
1429         /* we requeue for retry because the error was retryable, and
1430          * the request was not marked fast fail.  Note that above,
1431          * even if the request is marked fast fail, we still requeue
1432          * for queue congestion conditions (QUEUE_FULL or BUSY) */
1433         if ((++scmd->retries) <= scmd->allowed
1434             && !scsi_noretry_cmd(scmd)) {
1435                 return NEEDS_RETRY;
1436         } else {
1437                 /*
1438                  * no more retries - report this one back to upper level.
1439                  */
1440                 return SUCCESS;
1441         }
1442 }
1443
1444 static void eh_lock_door_done(struct request *req, int uptodate)
1445 {
1446         __blk_put_request(req->q, req);
1447 }
1448
1449 /**
1450  * scsi_eh_lock_door - Prevent medium removal for the specified device
1451  * @sdev:       SCSI device to prevent medium removal
1452  *
1453  * Locking:
1454  *      We must be called from process context; scsi_allocate_request()
1455  *      may sleep.
1456  *
1457  * Notes:
1458  *      We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
1459  *      head of the devices request queue, and continue.
1460  *
1461  * Bugs:
1462  *      scsi_allocate_request() may sleep waiting for existing requests to
1463  *      be processed.  However, since we haven't kicked off any request
1464  *      processing for this host, this may deadlock.
1465  *
1466  *      If scsi_allocate_request() fails for what ever reason, we
1467  *      completely forget to lock the door.
1468  */
1469 static void scsi_eh_lock_door(struct scsi_device *sdev)
1470 {
1471         struct request *req;
1472
1473         req = blk_get_request(sdev->request_queue, READ, GFP_KERNEL);
1474         if (!req)
1475                 return;
1476
1477         req->cmd[0] = ALLOW_MEDIUM_REMOVAL;
1478         req->cmd[1] = 0;
1479         req->cmd[2] = 0;
1480         req->cmd[3] = 0;
1481         req->cmd[4] = SCSI_REMOVAL_PREVENT;
1482         req->cmd[5] = 0;
1483
1484         req->cmd_len = COMMAND_SIZE(req->cmd[0]);
1485
1486         req->cmd_type = REQ_TYPE_BLOCK_PC;
1487         req->cmd_flags |= REQ_QUIET;
1488         req->timeout = 10 * HZ;
1489         req->retries = 5;
1490
1491         blk_execute_rq_nowait(req->q, NULL, req, 1, eh_lock_door_done);
1492 }
1493
1494 /**
1495  * scsi_restart_operations - restart io operations to the specified host.
1496  * @shost:      Host we are restarting.
1497  *
1498  * Notes:
1499  *    When we entered the error handler, we blocked all further i/o to
1500  *    this device.  we need to 'reverse' this process.
1501  */
1502 static void scsi_restart_operations(struct Scsi_Host *shost)
1503 {
1504         struct scsi_device *sdev;
1505         unsigned long flags;
1506
1507         /*
1508          * If the door was locked, we need to insert a door lock request
1509          * onto the head of the SCSI request queue for the device.  There
1510          * is no point trying to lock the door of an off-line device.
1511          */
1512         shost_for_each_device(sdev, shost) {
1513                 if (scsi_device_online(sdev) && sdev->locked)
1514                         scsi_eh_lock_door(sdev);
1515         }
1516
1517         /*
1518          * next free up anything directly waiting upon the host.  this
1519          * will be requests for character device operations, and also for
1520          * ioctls to queued block devices.
1521          */
1522         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: waking up host to restart\n",
1523                                           __func__));
1524
1525         spin_lock_irqsave(shost->host_lock, flags);
1526         if (scsi_host_set_state(shost, SHOST_RUNNING))
1527                 if (scsi_host_set_state(shost, SHOST_CANCEL))
1528                         BUG_ON(scsi_host_set_state(shost, SHOST_DEL));
1529         spin_unlock_irqrestore(shost->host_lock, flags);
1530
1531         wake_up(&shost->host_wait);
1532
1533         /*
1534          * finally we need to re-initiate requests that may be pending.  we will
1535          * have had everything blocked while error handling is taking place, and
1536          * now that error recovery is done, we will need to ensure that these
1537          * requests are started.
1538          */
1539         scsi_run_host_queues(shost);
1540 }
1541
1542 /**
1543  * scsi_eh_ready_devs - check device ready state and recover if not.
1544  * @shost:      host to be recovered.
1545  * @work_q:     &list_head for pending commands.
1546  * @done_q:     &list_head for processed commands.
1547  */
1548 void scsi_eh_ready_devs(struct Scsi_Host *shost,
1549                         struct list_head *work_q,
1550                         struct list_head *done_q)
1551 {
1552         if (!scsi_eh_stu(shost, work_q, done_q))
1553                 if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
1554                         if (!scsi_eh_target_reset(shost, work_q, done_q))
1555                                 if (!scsi_eh_bus_reset(shost, work_q, done_q))
1556                                         if (!scsi_eh_host_reset(work_q, done_q))
1557                                                 scsi_eh_offline_sdevs(work_q,
1558                                                                       done_q);
1559 }
1560 EXPORT_SYMBOL_GPL(scsi_eh_ready_devs);
1561
1562 /**
1563  * scsi_eh_flush_done_q - finish processed commands or retry them.
1564  * @done_q:     list_head of processed commands.
1565  */
1566 void scsi_eh_flush_done_q(struct list_head *done_q)
1567 {
1568         struct scsi_cmnd *scmd, *next;
1569
1570         list_for_each_entry_safe(scmd, next, done_q, eh_entry) {
1571                 list_del_init(&scmd->eh_entry);
1572                 if (scsi_device_online(scmd->device) &&
1573                     !scsi_noretry_cmd(scmd) &&
1574                     (++scmd->retries <= scmd->allowed)) {
1575                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush"
1576                                                           " retry cmd: %p\n",
1577                                                           current->comm,
1578                                                           scmd));
1579                                 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
1580                 } else {
1581                         /*
1582                          * If just we got sense for the device (called
1583                          * scsi_eh_get_sense), scmd->result is already
1584                          * set, do not set DRIVER_TIMEOUT.
1585                          */
1586                         if (!scmd->result)
1587                                 scmd->result |= (DRIVER_TIMEOUT << 24);
1588                         SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush finish"
1589                                                         " cmd: %p\n",
1590                                                         current->comm, scmd));
1591                         scsi_finish_command(scmd);
1592                 }
1593         }
1594 }
1595 EXPORT_SYMBOL(scsi_eh_flush_done_q);
1596
1597 /**
1598  * scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
1599  * @shost:      Host to unjam.
1600  *
1601  * Notes:
1602  *    When we come in here, we *know* that all commands on the bus have
1603  *    either completed, failed or timed out.  we also know that no further
1604  *    commands are being sent to the host, so things are relatively quiet
1605  *    and we have freedom to fiddle with things as we wish.
1606  *
1607  *    This is only the *default* implementation.  it is possible for
1608  *    individual drivers to supply their own version of this function, and
1609  *    if the maintainer wishes to do this, it is strongly suggested that
1610  *    this function be taken as a template and modified.  this function
1611  *    was designed to correctly handle problems for about 95% of the
1612  *    different cases out there, and it should always provide at least a
1613  *    reasonable amount of error recovery.
1614  *
1615  *    Any command marked 'failed' or 'timeout' must eventually have
1616  *    scsi_finish_cmd() called for it.  we do all of the retry stuff
1617  *    here, so when we restart the host after we return it should have an
1618  *    empty queue.
1619  */
1620 static void scsi_unjam_host(struct Scsi_Host *shost)
1621 {
1622         unsigned long flags;
1623         LIST_HEAD(eh_work_q);
1624         LIST_HEAD(eh_done_q);
1625
1626         spin_lock_irqsave(shost->host_lock, flags);
1627         list_splice_init(&shost->eh_cmd_q, &eh_work_q);
1628         spin_unlock_irqrestore(shost->host_lock, flags);
1629
1630         SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
1631
1632         if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
1633                 if (!scsi_eh_abort_cmds(&eh_work_q, &eh_done_q))
1634                         scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
1635
1636         scsi_eh_flush_done_q(&eh_done_q);
1637 }
1638
1639 /**
1640  * scsi_error_handler - SCSI error handler thread
1641  * @data:       Host for which we are running.
1642  *
1643  * Notes:
1644  *    This is the main error handling loop.  This is run as a kernel thread
1645  *    for every SCSI host and handles all error handling activity.
1646  */
1647 int scsi_error_handler(void *data)
1648 {
1649         struct Scsi_Host *shost = data;
1650
1651         /*
1652          * We use TASK_INTERRUPTIBLE so that the thread is not
1653          * counted against the load average as a running process.
1654          * We never actually get interrupted because kthread_run
1655          * disables signal delivery for the created thread.
1656          */
1657         set_current_state(TASK_INTERRUPTIBLE);
1658         while (!kthread_should_stop()) {
1659                 if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||
1660                     shost->host_failed != shost->host_busy) {
1661                         SCSI_LOG_ERROR_RECOVERY(1,
1662                                 printk("Error handler scsi_eh_%d sleeping\n",
1663                                         shost->host_no));
1664                         schedule();
1665                         set_current_state(TASK_INTERRUPTIBLE);
1666                         continue;
1667                 }
1668
1669                 __set_current_state(TASK_RUNNING);
1670                 SCSI_LOG_ERROR_RECOVERY(1,
1671                         printk("Error handler scsi_eh_%d waking up\n",
1672                                 shost->host_no));
1673
1674                 /*
1675                  * We have a host that is failing for some reason.  Figure out
1676                  * what we need to do to get it up and online again (if we can).
1677                  * If we fail, we end up taking the thing offline.
1678                  */
1679                 if (shost->transportt->eh_strategy_handler)
1680                         shost->transportt->eh_strategy_handler(shost);
1681                 else
1682                         scsi_unjam_host(shost);
1683
1684                 /*
1685                  * Note - if the above fails completely, the action is to take
1686                  * individual devices offline and flush the queue of any
1687                  * outstanding requests that may have been pending.  When we
1688                  * restart, we restart any I/O to any other devices on the bus
1689                  * which are still online.
1690                  */
1691                 scsi_restart_operations(shost);
1692                 set_current_state(TASK_INTERRUPTIBLE);
1693         }
1694         __set_current_state(TASK_RUNNING);
1695
1696         SCSI_LOG_ERROR_RECOVERY(1,
1697                 printk("Error handler scsi_eh_%d exiting\n", shost->host_no));
1698         shost->ehandler = NULL;
1699         return 0;
1700 }
1701
1702 /*
1703  * Function:    scsi_report_bus_reset()
1704  *
1705  * Purpose:     Utility function used by low-level drivers to report that
1706  *              they have observed a bus reset on the bus being handled.
1707  *
1708  * Arguments:   shost       - Host in question
1709  *              channel     - channel on which reset was observed.
1710  *
1711  * Returns:     Nothing
1712  *
1713  * Lock status: Host lock must be held.
1714  *
1715  * Notes:       This only needs to be called if the reset is one which
1716  *              originates from an unknown location.  Resets originated
1717  *              by the mid-level itself don't need to call this, but there
1718  *              should be no harm.
1719  *
1720  *              The main purpose of this is to make sure that a CHECK_CONDITION
1721  *              is properly treated.
1722  */
1723 void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
1724 {
1725         struct scsi_device *sdev;
1726
1727         __shost_for_each_device(sdev, shost) {
1728                 if (channel == sdev_channel(sdev))
1729                         __scsi_report_device_reset(sdev, NULL);
1730         }
1731 }
1732 EXPORT_SYMBOL(scsi_report_bus_reset);
1733
1734 /*
1735  * Function:    scsi_report_device_reset()
1736  *
1737  * Purpose:     Utility function used by low-level drivers to report that
1738  *              they have observed a device reset on the device being handled.
1739  *
1740  * Arguments:   shost       - Host in question
1741  *              channel     - channel on which reset was observed
1742  *              target      - target on which reset was observed
1743  *
1744  * Returns:     Nothing
1745  *
1746  * Lock status: Host lock must be held
1747  *
1748  * Notes:       This only needs to be called if the reset is one which
1749  *              originates from an unknown location.  Resets originated
1750  *              by the mid-level itself don't need to call this, but there
1751  *              should be no harm.
1752  *
1753  *              The main purpose of this is to make sure that a CHECK_CONDITION
1754  *              is properly treated.
1755  */
1756 void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
1757 {
1758         struct scsi_device *sdev;
1759
1760         __shost_for_each_device(sdev, shost) {
1761                 if (channel == sdev_channel(sdev) &&
1762                     target == sdev_id(sdev))
1763                         __scsi_report_device_reset(sdev, NULL);
1764         }
1765 }
1766 EXPORT_SYMBOL(scsi_report_device_reset);
1767
1768 static void
1769 scsi_reset_provider_done_command(struct scsi_cmnd *scmd)
1770 {
1771 }
1772
1773 /*
1774  * Function:    scsi_reset_provider
1775  *
1776  * Purpose:     Send requested reset to a bus or device at any phase.
1777  *
1778  * Arguments:   device  - device to send reset to
1779  *              flag - reset type (see scsi.h)
1780  *
1781  * Returns:     SUCCESS/FAILURE.
1782  *
1783  * Notes:       This is used by the SCSI Generic driver to provide
1784  *              Bus/Device reset capability.
1785  */
1786 int
1787 scsi_reset_provider(struct scsi_device *dev, int flag)
1788 {
1789         struct scsi_cmnd *scmd = scsi_get_command(dev, GFP_KERNEL);
1790         struct Scsi_Host *shost = dev->host;
1791         struct request req;
1792         unsigned long flags;
1793         int rtn;
1794
1795         blk_rq_init(NULL, &req);
1796         scmd->request = &req;
1797
1798         scmd->cmnd = req.cmd;
1799
1800         scmd->scsi_done         = scsi_reset_provider_done_command;
1801         memset(&scmd->sdb, 0, sizeof(scmd->sdb));
1802
1803         scmd->cmd_len                   = 0;
1804
1805         scmd->sc_data_direction         = DMA_BIDIRECTIONAL;
1806
1807         spin_lock_irqsave(shost->host_lock, flags);
1808         shost->tmf_in_progress = 1;
1809         spin_unlock_irqrestore(shost->host_lock, flags);
1810
1811         switch (flag) {
1812         case SCSI_TRY_RESET_DEVICE:
1813                 rtn = scsi_try_bus_device_reset(scmd);
1814                 if (rtn == SUCCESS)
1815                         break;
1816                 /* FALLTHROUGH */
1817         case SCSI_TRY_RESET_TARGET:
1818                 rtn = scsi_try_target_reset(scmd);
1819                 if (rtn == SUCCESS)
1820                         break;
1821                 /* FALLTHROUGH */
1822         case SCSI_TRY_RESET_BUS:
1823                 rtn = scsi_try_bus_reset(scmd);
1824                 if (rtn == SUCCESS)
1825                         break;
1826                 /* FALLTHROUGH */
1827         case SCSI_TRY_RESET_HOST:
1828                 rtn = scsi_try_host_reset(scmd);
1829                 break;
1830         default:
1831                 rtn = FAILED;
1832         }
1833
1834         spin_lock_irqsave(shost->host_lock, flags);
1835         shost->tmf_in_progress = 0;
1836         spin_unlock_irqrestore(shost->host_lock, flags);
1837
1838         /*
1839          * be sure to wake up anyone who was sleeping or had their queue
1840          * suspended while we performed the TMF.
1841          */
1842         SCSI_LOG_ERROR_RECOVERY(3,
1843                 printk("%s: waking up host to restart after TMF\n",
1844                 __func__));
1845
1846         wake_up(&shost->host_wait);
1847
1848         scsi_run_host_queues(shost);
1849
1850         scsi_next_command(scmd);
1851         return rtn;
1852 }
1853 EXPORT_SYMBOL(scsi_reset_provider);
1854
1855 /**
1856  * scsi_normalize_sense - normalize main elements from either fixed or
1857  *                      descriptor sense data format into a common format.
1858  *
1859  * @sense_buffer:       byte array containing sense data returned by device
1860  * @sb_len:             number of valid bytes in sense_buffer
1861  * @sshdr:              pointer to instance of structure that common
1862  *                      elements are written to.
1863  *
1864  * Notes:
1865  *      The "main elements" from sense data are: response_code, sense_key,
1866  *      asc, ascq and additional_length (only for descriptor format).
1867  *
1868  *      Typically this function can be called after a device has
1869  *      responded to a SCSI command with the CHECK_CONDITION status.
1870  *
1871  * Return value:
1872  *      1 if valid sense data information found, else 0;
1873  */
1874 int scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
1875                          struct scsi_sense_hdr *sshdr)
1876 {
1877         if (!sense_buffer || !sb_len)
1878                 return 0;
1879
1880         memset(sshdr, 0, sizeof(struct scsi_sense_hdr));
1881
1882         sshdr->response_code = (sense_buffer[0] & 0x7f);
1883
1884         if (!scsi_sense_valid(sshdr))
1885                 return 0;
1886
1887         if (sshdr->response_code >= 0x72) {
1888                 /*
1889                  * descriptor format
1890                  */
1891                 if (sb_len > 1)
1892                         sshdr->sense_key = (sense_buffer[1] & 0xf);
1893                 if (sb_len > 2)
1894                         sshdr->asc = sense_buffer[2];
1895                 if (sb_len > 3)
1896                         sshdr->ascq = sense_buffer[3];
1897                 if (sb_len > 7)
1898                         sshdr->additional_length = sense_buffer[7];
1899         } else {
1900                 /*
1901                  * fixed format
1902                  */
1903                 if (sb_len > 2)
1904                         sshdr->sense_key = (sense_buffer[2] & 0xf);
1905                 if (sb_len > 7) {
1906                         sb_len = (sb_len < (sense_buffer[7] + 8)) ?
1907                                          sb_len : (sense_buffer[7] + 8);
1908                         if (sb_len > 12)
1909                                 sshdr->asc = sense_buffer[12];
1910                         if (sb_len > 13)
1911                                 sshdr->ascq = sense_buffer[13];
1912                 }
1913         }
1914
1915         return 1;
1916 }
1917 EXPORT_SYMBOL(scsi_normalize_sense);
1918
1919 int scsi_command_normalize_sense(struct scsi_cmnd *cmd,
1920                                  struct scsi_sense_hdr *sshdr)
1921 {
1922         return scsi_normalize_sense(cmd->sense_buffer,
1923                         SCSI_SENSE_BUFFERSIZE, sshdr);
1924 }
1925 EXPORT_SYMBOL(scsi_command_normalize_sense);
1926
1927 /**
1928  * scsi_sense_desc_find - search for a given descriptor type in descriptor sense data format.
1929  * @sense_buffer:       byte array of descriptor format sense data
1930  * @sb_len:             number of valid bytes in sense_buffer
1931  * @desc_type:          value of descriptor type to find
1932  *                      (e.g. 0 -> information)
1933  *
1934  * Notes:
1935  *      only valid when sense data is in descriptor format
1936  *
1937  * Return value:
1938  *      pointer to start of (first) descriptor if found else NULL
1939  */
1940 const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len,
1941                                 int desc_type)
1942 {
1943         int add_sen_len, add_len, desc_len, k;
1944         const u8 * descp;
1945
1946         if ((sb_len < 8) || (0 == (add_sen_len = sense_buffer[7])))
1947                 return NULL;
1948         if ((sense_buffer[0] < 0x72) || (sense_buffer[0] > 0x73))
1949                 return NULL;
1950         add_sen_len = (add_sen_len < (sb_len - 8)) ?
1951                         add_sen_len : (sb_len - 8);
1952         descp = &sense_buffer[8];
1953         for (desc_len = 0, k = 0; k < add_sen_len; k += desc_len) {
1954                 descp += desc_len;
1955                 add_len = (k < (add_sen_len - 1)) ? descp[1]: -1;
1956                 desc_len = add_len + 2;
1957                 if (descp[0] == desc_type)
1958                         return descp;
1959                 if (add_len < 0) // short descriptor ??
1960                         break;
1961         }
1962         return NULL;
1963 }
1964 EXPORT_SYMBOL(scsi_sense_desc_find);
1965
1966 /**
1967  * scsi_get_sense_info_fld - get information field from sense data (either fixed or descriptor format)
1968  * @sense_buffer:       byte array of sense data
1969  * @sb_len:             number of valid bytes in sense_buffer
1970  * @info_out:           pointer to 64 integer where 8 or 4 byte information
1971  *                      field will be placed if found.
1972  *
1973  * Return value:
1974  *      1 if information field found, 0 if not found.
1975  */
1976 int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
1977                             u64 * info_out)
1978 {
1979         int j;
1980         const u8 * ucp;
1981         u64 ull;
1982
1983         if (sb_len < 7)
1984                 return 0;
1985         switch (sense_buffer[0] & 0x7f) {
1986         case 0x70:
1987         case 0x71:
1988                 if (sense_buffer[0] & 0x80) {
1989                         *info_out = (sense_buffer[3] << 24) +
1990                                     (sense_buffer[4] << 16) +
1991                                     (sense_buffer[5] << 8) + sense_buffer[6];
1992                         return 1;
1993                 } else
1994                         return 0;
1995         case 0x72:
1996         case 0x73:
1997                 ucp = scsi_sense_desc_find(sense_buffer, sb_len,
1998                                            0 /* info desc */);
1999                 if (ucp && (0xa == ucp[1])) {
2000                         ull = 0;
2001                         for (j = 0; j < 8; ++j) {
2002                                 if (j > 0)
2003                                         ull <<= 8;
2004                                 ull |= ucp[4 + j];
2005                         }
2006                         *info_out = ull;
2007                         return 1;
2008                 } else
2009                         return 0;
2010         default:
2011                 return 0;
2012         }
2013 }
2014 EXPORT_SYMBOL(scsi_get_sense_info_fld);
2015
2016 /**
2017  * scsi_build_sense_buffer - build sense data in a buffer
2018  * @desc:       Sense format (non zero == descriptor format,
2019  *              0 == fixed format)
2020  * @buf:        Where to build sense data
2021  * @key:        Sense key
2022  * @asc:        Additional sense code
2023  * @ascq:       Additional sense code qualifier
2024  *
2025  **/
2026 void scsi_build_sense_buffer(int desc, u8 *buf, u8 key, u8 asc, u8 ascq)
2027 {
2028         if (desc) {
2029                 buf[0] = 0x72;  /* descriptor, current */
2030                 buf[1] = key;
2031                 buf[2] = asc;
2032                 buf[3] = ascq;
2033                 buf[7] = 0;
2034         } else {
2035                 buf[0] = 0x70;  /* fixed, current */
2036                 buf[2] = key;
2037                 buf[7] = 0xa;
2038                 buf[12] = asc;
2039                 buf[13] = ascq;
2040         }
2041 }
2042 EXPORT_SYMBOL(scsi_build_sense_buffer);