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