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