linux/drivers/scsi/scsi_error.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *  scsi_error.c Copyright (C) 1997 Eric Youngdale
   4 *
   5 *  SCSI error/timeout handling
   6 *      Initial versions: Eric Youngdale.  Based upon conversations with
   7 *                        Leonard Zubkoff and David Miller at Linux Expo,
   8 *                        ideas originating from all over the place.
   9 *
  10 *      Restructured scsi_unjam_host and associated functions.
  11 *      September 04, 2002 Mike Anderson (andmike@us.ibm.com)
  12 *
  13 *      Forward port of Russell King's (rmk@arm.linux.org.uk) changes and
  14 *      minor cleanups.
  15 *      September 30, 2002 Mike Anderson (andmike@us.ibm.com)
  16 */
  17
  18#include <linux/module.h>
  19#include <linux/sched.h>
  20#include <linux/gfp.h>
  21#include <linux/timer.h>
  22#include <linux/string.h>
  23#include <linux/kernel.h>
  24#include <linux/freezer.h>
  25#include <linux/kthread.h>
  26#include <linux/interrupt.h>
  27#include <linux/blkdev.h>
  28#include <linux/delay.h>
  29#include <linux/jiffies.h>
  30
  31#include <scsi/scsi.h>
  32#include <scsi/scsi_cmnd.h>
  33#include <scsi/scsi_dbg.h>
  34#include <scsi/scsi_device.h>
  35#include <scsi/scsi_driver.h>
  36#include <scsi/scsi_eh.h>
  37#include <scsi/scsi_common.h>
  38#include <scsi/scsi_transport.h>
  39#include <scsi/scsi_host.h>
  40#include <scsi/scsi_ioctl.h>
  41#include <scsi/scsi_dh.h>
  42#include <scsi/scsi_devinfo.h>
  43#include <scsi/sg.h>
  44
  45#include "scsi_priv.h"
  46#include "scsi_logging.h"
  47#include "scsi_transport_api.h"
  48
  49#include <trace/events/scsi.h>
  50
  51#include <asm/unaligned.h>
  52
  53static void scsi_eh_done(struct scsi_cmnd *scmd);
  54
  55/*
  56 * These should *probably* be handled by the host itself.
  57 * Since it is allowed to sleep, it probably should.
  58 */
  59#define BUS_RESET_SETTLE_TIME   (10)
  60#define HOST_RESET_SETTLE_TIME  (10)
  61
  62static int scsi_eh_try_stu(struct scsi_cmnd *scmd);
  63static enum scsi_disposition scsi_try_to_abort_cmd(struct scsi_host_template *,
  64                                                   struct scsi_cmnd *);
  65
  66void scsi_eh_wakeup(struct Scsi_Host *shost)
  67{
  68        lockdep_assert_held(shost->host_lock);
  69
  70        if (scsi_host_busy(shost) == shost->host_failed) {
  71                trace_scsi_eh_wakeup(shost);
  72                wake_up_process(shost->ehandler);
  73                SCSI_LOG_ERROR_RECOVERY(5, shost_printk(KERN_INFO, shost,
  74                        "Waking error handler thread\n"));
  75        }
  76}
  77
  78/**
  79 * scsi_schedule_eh - schedule EH for SCSI host
  80 * @shost:      SCSI host to invoke error handling on.
  81 *
  82 * Schedule SCSI EH without scmd.
  83 */
  84void scsi_schedule_eh(struct Scsi_Host *shost)
  85{
  86        unsigned long flags;
  87
  88        spin_lock_irqsave(shost->host_lock, flags);
  89
  90        if (scsi_host_set_state(shost, SHOST_RECOVERY) == 0 ||
  91            scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY) == 0) {
  92                shost->host_eh_scheduled++;
  93                scsi_eh_wakeup(shost);
  94        }
  95
  96        spin_unlock_irqrestore(shost->host_lock, flags);
  97}
  98EXPORT_SYMBOL_GPL(scsi_schedule_eh);
  99
 100static int scsi_host_eh_past_deadline(struct Scsi_Host *shost)
 101{
 102        if (!shost->last_reset || shost->eh_deadline == -1)
 103                return 0;
 104
 105        /*
 106         * 32bit accesses are guaranteed to be atomic
 107         * (on all supported architectures), so instead
 108         * of using a spinlock we can as well double check
 109         * if eh_deadline has been set to 'off' during the
 110         * time_before call.
 111         */
 112        if (time_before(jiffies, shost->last_reset + shost->eh_deadline) &&
 113            shost->eh_deadline > -1)
 114                return 0;
 115
 116        return 1;
 117}
 118
 119static bool scsi_cmd_retry_allowed(struct scsi_cmnd *cmd)
 120{
 121        if (cmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT)
 122                return true;
 123
 124        return ++cmd->retries <= cmd->allowed;
 125}
 126
 127static bool scsi_eh_should_retry_cmd(struct scsi_cmnd *cmd)
 128{
 129        struct scsi_device *sdev = cmd->device;
 130        struct Scsi_Host *host = sdev->host;
 131
 132        if (host->hostt->eh_should_retry_cmd)
 133                return  host->hostt->eh_should_retry_cmd(cmd);
 134
 135        return true;
 136}
 137
 138/**
 139 * scmd_eh_abort_handler - Handle command aborts
 140 * @work:       command to be aborted.
 141 *
 142 * Note: this function must be called only for a command that has timed out.
 143 * Because the block layer marks a request as complete before it calls
 144 * scsi_times_out(), a .scsi_done() call from the LLD for a command that has
 145 * timed out do not have any effect. Hence it is safe to call
 146 * scsi_finish_command() from this function.
 147 */
 148void
 149scmd_eh_abort_handler(struct work_struct *work)
 150{
 151        struct scsi_cmnd *scmd =
 152                container_of(work, struct scsi_cmnd, abort_work.work);
 153        struct scsi_device *sdev = scmd->device;
 154        enum scsi_disposition rtn;
 155
 156        if (scsi_host_eh_past_deadline(sdev->host)) {
 157                SCSI_LOG_ERROR_RECOVERY(3,
 158                        scmd_printk(KERN_INFO, scmd,
 159                                    "eh timeout, not aborting\n"));
 160        } else {
 161                SCSI_LOG_ERROR_RECOVERY(3,
 162                        scmd_printk(KERN_INFO, scmd,
 163                                    "aborting command\n"));
 164                rtn = scsi_try_to_abort_cmd(sdev->host->hostt, scmd);
 165                if (rtn == SUCCESS) {
 166                        set_host_byte(scmd, DID_TIME_OUT);
 167                        if (scsi_host_eh_past_deadline(sdev->host)) {
 168                                SCSI_LOG_ERROR_RECOVERY(3,
 169                                        scmd_printk(KERN_INFO, scmd,
 170                                                    "eh timeout, not retrying "
 171                                                    "aborted command\n"));
 172                        } else if (!scsi_noretry_cmd(scmd) &&
 173                                   scsi_cmd_retry_allowed(scmd) &&
 174                                scsi_eh_should_retry_cmd(scmd)) {
 175                                SCSI_LOG_ERROR_RECOVERY(3,
 176                                        scmd_printk(KERN_WARNING, scmd,
 177                                                    "retry aborted command\n"));
 178                                scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
 179                                return;
 180                        } else {
 181                                SCSI_LOG_ERROR_RECOVERY(3,
 182                                        scmd_printk(KERN_WARNING, scmd,
 183                                                    "finish aborted command\n"));
 184                                scsi_finish_command(scmd);
 185                                return;
 186                        }
 187                } else {
 188                        SCSI_LOG_ERROR_RECOVERY(3,
 189                                scmd_printk(KERN_INFO, scmd,
 190                                            "cmd abort %s\n",
 191                                            (rtn == FAST_IO_FAIL) ?
 192                                            "not send" : "failed"));
 193                }
 194        }
 195
 196        scsi_eh_scmd_add(scmd);
 197}
 198
 199/**
 200 * scsi_abort_command - schedule a command abort
 201 * @scmd:       scmd to abort.
 202 *
 203 * We only need to abort commands after a command timeout
 204 */
 205static int
 206scsi_abort_command(struct scsi_cmnd *scmd)
 207{
 208        struct scsi_device *sdev = scmd->device;
 209        struct Scsi_Host *shost = sdev->host;
 210        unsigned long flags;
 211
 212        if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) {
 213                /*
 214                 * Retry after abort failed, escalate to next level.
 215                 */
 216                SCSI_LOG_ERROR_RECOVERY(3,
 217                        scmd_printk(KERN_INFO, scmd,
 218                                    "previous abort failed\n"));
 219                BUG_ON(delayed_work_pending(&scmd->abort_work));
 220                return FAILED;
 221        }
 222
 223        spin_lock_irqsave(shost->host_lock, flags);
 224        if (shost->eh_deadline != -1 && !shost->last_reset)
 225                shost->last_reset = jiffies;
 226        spin_unlock_irqrestore(shost->host_lock, flags);
 227
 228        scmd->eh_eflags |= SCSI_EH_ABORT_SCHEDULED;
 229        SCSI_LOG_ERROR_RECOVERY(3,
 230                scmd_printk(KERN_INFO, scmd, "abort scheduled\n"));
 231        queue_delayed_work(shost->tmf_work_q, &scmd->abort_work, HZ / 100);
 232        return SUCCESS;
 233}
 234
 235/**
 236 * scsi_eh_reset - call into ->eh_action to reset internal counters
 237 * @scmd:       scmd to run eh on.
 238 *
 239 * The scsi driver might be carrying internal state about the
 240 * devices, so we need to call into the driver to reset the
 241 * internal state once the error handler is started.
 242 */
 243static void scsi_eh_reset(struct scsi_cmnd *scmd)
 244{
 245        if (!blk_rq_is_passthrough(scmd->request)) {
 246                struct scsi_driver *sdrv = scsi_cmd_to_driver(scmd);
 247                if (sdrv->eh_reset)
 248                        sdrv->eh_reset(scmd);
 249        }
 250}
 251
 252static void scsi_eh_inc_host_failed(struct rcu_head *head)
 253{
 254        struct scsi_cmnd *scmd = container_of(head, typeof(*scmd), rcu);
 255        struct Scsi_Host *shost = scmd->device->host;
 256        unsigned long flags;
 257
 258        spin_lock_irqsave(shost->host_lock, flags);
 259        shost->host_failed++;
 260        scsi_eh_wakeup(shost);
 261        spin_unlock_irqrestore(shost->host_lock, flags);
 262}
 263
 264/**
 265 * scsi_eh_scmd_add - add scsi cmd to error handling.
 266 * @scmd:       scmd to run eh on.
 267 */
 268void scsi_eh_scmd_add(struct scsi_cmnd *scmd)
 269{
 270        struct Scsi_Host *shost = scmd->device->host;
 271        unsigned long flags;
 272        int ret;
 273
 274        WARN_ON_ONCE(!shost->ehandler);
 275
 276        spin_lock_irqsave(shost->host_lock, flags);
 277        if (scsi_host_set_state(shost, SHOST_RECOVERY)) {
 278                ret = scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY);
 279                WARN_ON_ONCE(ret);
 280        }
 281        if (shost->eh_deadline != -1 && !shost->last_reset)
 282                shost->last_reset = jiffies;
 283
 284        scsi_eh_reset(scmd);
 285        list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
 286        spin_unlock_irqrestore(shost->host_lock, flags);
 287        /*
 288         * Ensure that all tasks observe the host state change before the
 289         * host_failed change.
 290         */
 291        call_rcu(&scmd->rcu, scsi_eh_inc_host_failed);
 292}
 293
 294/**
 295 * scsi_times_out - Timeout function for normal scsi commands.
 296 * @req:        request that is timing out.
 297 *
 298 * Notes:
 299 *     We do not need to lock this.  There is the potential for a race
 300 *     only in that the normal completion handling might run, but if the
 301 *     normal completion function determines that the timer has already
 302 *     fired, then it mustn't do anything.
 303 */
 304enum blk_eh_timer_return scsi_times_out(struct request *req)
 305{
 306        struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(req);
 307        enum blk_eh_timer_return rtn = BLK_EH_DONE;
 308        struct Scsi_Host *host = scmd->device->host;
 309
 310        trace_scsi_dispatch_cmd_timeout(scmd);
 311        scsi_log_completion(scmd, TIMEOUT_ERROR);
 312
 313        if (host->eh_deadline != -1 && !host->last_reset)
 314                host->last_reset = jiffies;
 315
 316        if (host->hostt->eh_timed_out)
 317                rtn = host->hostt->eh_timed_out(scmd);
 318
 319        if (rtn == BLK_EH_DONE) {
 320                /*
 321                 * Set the command to complete first in order to prevent a real
 322                 * completion from releasing the command while error handling
 323                 * is using it. If the command was already completed, then the
 324                 * lower level driver beat the timeout handler, and it is safe
 325                 * to return without escalating error recovery.
 326                 *
 327                 * If timeout handling lost the race to a real completion, the
 328                 * block layer may ignore that due to a fake timeout injection,
 329                 * so return RESET_TIMER to allow error handling another shot
 330                 * at this command.
 331                 */
 332                if (test_and_set_bit(SCMD_STATE_COMPLETE, &scmd->state))
 333                        return BLK_EH_RESET_TIMER;
 334                if (scsi_abort_command(scmd) != SUCCESS) {
 335                        set_host_byte(scmd, DID_TIME_OUT);
 336                        scsi_eh_scmd_add(scmd);
 337                }
 338        }
 339
 340        return rtn;
 341}
 342
 343/**
 344 * scsi_block_when_processing_errors - Prevent cmds from being queued.
 345 * @sdev:       Device on which we are performing recovery.
 346 *
 347 * Description:
 348 *     We block until the host is out of error recovery, and then check to
 349 *     see whether the host or the device is offline.
 350 *
 351 * Return value:
 352 *     0 when dev was taken offline by error recovery. 1 OK to proceed.
 353 */
 354int scsi_block_when_processing_errors(struct scsi_device *sdev)
 355{
 356        int online;
 357
 358        wait_event(sdev->host->host_wait, !scsi_host_in_recovery(sdev->host));
 359
 360        online = scsi_device_online(sdev);
 361
 362        return online;
 363}
 364EXPORT_SYMBOL(scsi_block_when_processing_errors);
 365
 366#ifdef CONFIG_SCSI_LOGGING
 367/**
 368 * scsi_eh_prt_fail_stats - Log info on failures.
 369 * @shost:      scsi host being recovered.
 370 * @work_q:     Queue of scsi cmds to process.
 371 */
 372static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
 373                                          struct list_head *work_q)
 374{
 375        struct scsi_cmnd *scmd;
 376        struct scsi_device *sdev;
 377        int total_failures = 0;
 378        int cmd_failed = 0;
 379        int cmd_cancel = 0;
 380        int devices_failed = 0;
 381
 382        shost_for_each_device(sdev, shost) {
 383                list_for_each_entry(scmd, work_q, eh_entry) {
 384                        if (scmd->device == sdev) {
 385                                ++total_failures;
 386                                if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED)
 387                                        ++cmd_cancel;
 388                                else
 389                                        ++cmd_failed;
 390                        }
 391                }
 392
 393                if (cmd_cancel || cmd_failed) {
 394                        SCSI_LOG_ERROR_RECOVERY(3,
 395                                shost_printk(KERN_INFO, shost,
 396                                            "%s: cmds failed: %d, cancel: %d\n",
 397                                            __func__, cmd_failed,
 398                                            cmd_cancel));
 399                        cmd_cancel = 0;
 400                        cmd_failed = 0;
 401                        ++devices_failed;
 402                }
 403        }
 404
 405        SCSI_LOG_ERROR_RECOVERY(2, shost_printk(KERN_INFO, shost,
 406                                   "Total of %d commands on %d"
 407                                   " devices require eh work\n",
 408                                   total_failures, devices_failed));
 409}
 410#endif
 411
 412 /**
 413 * scsi_report_lun_change - Set flag on all *other* devices on the same target
 414 *                          to indicate that a UNIT ATTENTION is expected.
 415 * @sdev:       Device reporting the UNIT ATTENTION
 416 */
 417static void scsi_report_lun_change(struct scsi_device *sdev)
 418{
 419        sdev->sdev_target->expecting_lun_change = 1;
 420}
 421
 422/**
 423 * scsi_report_sense - Examine scsi sense information and log messages for
 424 *                     certain conditions, also issue uevents for some of them.
 425 * @sdev:       Device reporting the sense code
 426 * @sshdr:      sshdr to be examined
 427 */
 428static void scsi_report_sense(struct scsi_device *sdev,
 429                              struct scsi_sense_hdr *sshdr)
 430{
 431        enum scsi_device_event evt_type = SDEV_EVT_MAXBITS;     /* i.e. none */
 432
 433        if (sshdr->sense_key == UNIT_ATTENTION) {
 434                if (sshdr->asc == 0x3f && sshdr->ascq == 0x03) {
 435                        evt_type = SDEV_EVT_INQUIRY_CHANGE_REPORTED;
 436                        sdev_printk(KERN_WARNING, sdev,
 437                                    "Inquiry data has changed");
 438                } else if (sshdr->asc == 0x3f && sshdr->ascq == 0x0e) {
 439                        evt_type = SDEV_EVT_LUN_CHANGE_REPORTED;
 440                        scsi_report_lun_change(sdev);
 441                        sdev_printk(KERN_WARNING, sdev,
 442                                    "Warning! Received an indication that the "
 443                                    "LUN assignments on this target have "
 444                                    "changed. The Linux SCSI layer does not "
 445                                    "automatically remap LUN assignments.\n");
 446                } else if (sshdr->asc == 0x3f)
 447                        sdev_printk(KERN_WARNING, sdev,
 448                                    "Warning! Received an indication that the "
 449                                    "operating parameters on this target have "
 450                                    "changed. The Linux SCSI layer does not "
 451                                    "automatically adjust these parameters.\n");
 452
 453                if (sshdr->asc == 0x38 && sshdr->ascq == 0x07) {
 454                        evt_type = SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED;
 455                        sdev_printk(KERN_WARNING, sdev,
 456                                    "Warning! Received an indication that the "
 457                                    "LUN reached a thin provisioning soft "
 458                                    "threshold.\n");
 459                }
 460
 461                if (sshdr->asc == 0x29) {
 462                        evt_type = SDEV_EVT_POWER_ON_RESET_OCCURRED;
 463                        sdev_printk(KERN_WARNING, sdev,
 464                                    "Power-on or device reset occurred\n");
 465                }
 466
 467                if (sshdr->asc == 0x2a && sshdr->ascq == 0x01) {
 468                        evt_type = SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED;
 469                        sdev_printk(KERN_WARNING, sdev,
 470                                    "Mode parameters changed");
 471                } else if (sshdr->asc == 0x2a && sshdr->ascq == 0x06) {
 472                        evt_type = SDEV_EVT_ALUA_STATE_CHANGE_REPORTED;
 473                        sdev_printk(KERN_WARNING, sdev,
 474                                    "Asymmetric access state changed");
 475                } else if (sshdr->asc == 0x2a && sshdr->ascq == 0x09) {
 476                        evt_type = SDEV_EVT_CAPACITY_CHANGE_REPORTED;
 477                        sdev_printk(KERN_WARNING, sdev,
 478                                    "Capacity data has changed");
 479                } else if (sshdr->asc == 0x2a)
 480                        sdev_printk(KERN_WARNING, sdev,
 481                                    "Parameters changed");
 482        }
 483
 484        if (evt_type != SDEV_EVT_MAXBITS) {
 485                set_bit(evt_type, sdev->pending_events);
 486                schedule_work(&sdev->event_work);
 487        }
 488}
 489
 490/**
 491 * scsi_check_sense - Examine scsi cmd sense
 492 * @scmd:       Cmd to have sense checked.
 493 *
 494 * Return value:
 495 *      SUCCESS or FAILED or NEEDS_RETRY or ADD_TO_MLQUEUE
 496 *
 497 * Notes:
 498 *      When a deferred error is detected the current command has
 499 *      not been executed and needs retrying.
 500 */
 501enum scsi_disposition scsi_check_sense(struct scsi_cmnd *scmd)
 502{
 503        struct scsi_device *sdev = scmd->device;
 504        struct scsi_sense_hdr sshdr;
 505
 506        if (! scsi_command_normalize_sense(scmd, &sshdr))
 507                return FAILED;  /* no valid sense data */
 508
 509        scsi_report_sense(sdev, &sshdr);
 510
 511        if (scsi_sense_is_deferred(&sshdr))
 512                return NEEDS_RETRY;
 513
 514        if (sdev->handler && sdev->handler->check_sense) {
 515                enum scsi_disposition rc;
 516
 517                rc = sdev->handler->check_sense(sdev, &sshdr);
 518                if (rc != SCSI_RETURN_NOT_HANDLED)
 519                        return rc;
 520                /* handler does not care. Drop down to default handling */
 521        }
 522
 523        if (scmd->cmnd[0] == TEST_UNIT_READY && scmd->scsi_done != scsi_eh_done)
 524                /*
 525                 * nasty: for mid-layer issued TURs, we need to return the
 526                 * actual sense data without any recovery attempt.  For eh
 527                 * issued ones, we need to try to recover and interpret
 528                 */
 529                return SUCCESS;
 530
 531        /*
 532         * Previous logic looked for FILEMARK, EOM or ILI which are
 533         * mainly associated with tapes and returned SUCCESS.
 534         */
 535        if (sshdr.response_code == 0x70) {
 536                /* fixed format */
 537                if (scmd->sense_buffer[2] & 0xe0)
 538                        return SUCCESS;
 539        } else {
 540                /*
 541                 * descriptor format: look for "stream commands sense data
 542                 * descriptor" (see SSC-3). Assume single sense data
 543                 * descriptor. Ignore ILI from SBC-2 READ LONG and WRITE LONG.
 544                 */
 545                if ((sshdr.additional_length > 3) &&
 546                    (scmd->sense_buffer[8] == 0x4) &&
 547                    (scmd->sense_buffer[11] & 0xe0))
 548                        return SUCCESS;
 549        }
 550
 551        switch (sshdr.sense_key) {
 552        case NO_SENSE:
 553                return SUCCESS;
 554        case RECOVERED_ERROR:
 555                return /* soft_error */ SUCCESS;
 556
 557        case ABORTED_COMMAND:
 558                if (sshdr.asc == 0x10) /* DIF */
 559                        return SUCCESS;
 560
 561                if (sshdr.asc == 0x44 && sdev->sdev_bflags & BLIST_RETRY_ITF)
 562                        return ADD_TO_MLQUEUE;
 563                if (sshdr.asc == 0xc1 && sshdr.ascq == 0x01 &&
 564                    sdev->sdev_bflags & BLIST_RETRY_ASC_C1)
 565                        return ADD_TO_MLQUEUE;
 566
 567                return NEEDS_RETRY;
 568        case NOT_READY:
 569        case UNIT_ATTENTION:
 570                /*
 571                 * if we are expecting a cc/ua because of a bus reset that we
 572                 * performed, treat this just as a retry.  otherwise this is
 573                 * information that we should pass up to the upper-level driver
 574                 * so that we can deal with it there.
 575                 */
 576                if (scmd->device->expecting_cc_ua) {
 577                        /*
 578                         * Because some device does not queue unit
 579                         * attentions correctly, we carefully check
 580                         * additional sense code and qualifier so as
 581                         * not to squash media change unit attention.
 582                         */
 583                        if (sshdr.asc != 0x28 || sshdr.ascq != 0x00) {
 584                                scmd->device->expecting_cc_ua = 0;
 585                                return NEEDS_RETRY;
 586                        }
 587                }
 588                /*
 589                 * we might also expect a cc/ua if another LUN on the target
 590                 * reported a UA with an ASC/ASCQ of 3F 0E -
 591                 * REPORTED LUNS DATA HAS CHANGED.
 592                 */
 593                if (scmd->device->sdev_target->expecting_lun_change &&
 594                    sshdr.asc == 0x3f && sshdr.ascq == 0x0e)
 595                        return NEEDS_RETRY;
 596                /*
 597                 * if the device is in the process of becoming ready, we
 598                 * should retry.
 599                 */
 600                if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01))
 601                        return NEEDS_RETRY;
 602                /*
 603                 * if the device is not started, we need to wake
 604                 * the error handler to start the motor
 605                 */
 606                if (scmd->device->allow_restart &&
 607                    (sshdr.asc == 0x04) && (sshdr.ascq == 0x02))
 608                        return FAILED;
 609                /*
 610                 * Pass the UA upwards for a determination in the completion
 611                 * functions.
 612                 */
 613                return SUCCESS;
 614
 615                /* these are not supported */
 616        case DATA_PROTECT:
 617                if (sshdr.asc == 0x27 && sshdr.ascq == 0x07) {
 618                        /* Thin provisioning hard threshold reached */
 619                        set_host_byte(scmd, DID_ALLOC_FAILURE);
 620                        return SUCCESS;
 621                }
 622                fallthrough;
 623        case COPY_ABORTED:
 624        case VOLUME_OVERFLOW:
 625        case MISCOMPARE:
 626        case BLANK_CHECK:
 627                set_host_byte(scmd, DID_TARGET_FAILURE);
 628                return SUCCESS;
 629
 630        case MEDIUM_ERROR:
 631                if (sshdr.asc == 0x11 || /* UNRECOVERED READ ERR */
 632                    sshdr.asc == 0x13 || /* AMNF DATA FIELD */
 633                    sshdr.asc == 0x14) { /* RECORD NOT FOUND */
 634                        set_host_byte(scmd, DID_MEDIUM_ERROR);
 635                        return SUCCESS;
 636                }
 637                return NEEDS_RETRY;
 638
 639        case HARDWARE_ERROR:
 640                if (scmd->device->retry_hwerror)
 641                        return ADD_TO_MLQUEUE;
 642                else
 643                        set_host_byte(scmd, DID_TARGET_FAILURE);
 644                fallthrough;
 645
 646        case ILLEGAL_REQUEST:
 647                if (sshdr.asc == 0x20 || /* Invalid command operation code */
 648                    sshdr.asc == 0x21 || /* Logical block address out of range */
 649                    sshdr.asc == 0x22 || /* Invalid function */
 650                    sshdr.asc == 0x24 || /* Invalid field in cdb */
 651                    sshdr.asc == 0x26 || /* Parameter value invalid */
 652                    sshdr.asc == 0x27) { /* Write protected */
 653                        set_host_byte(scmd, DID_TARGET_FAILURE);
 654                }
 655                return SUCCESS;
 656
 657        default:
 658                return SUCCESS;
 659        }
 660}
 661EXPORT_SYMBOL_GPL(scsi_check_sense);
 662
 663static void scsi_handle_queue_ramp_up(struct scsi_device *sdev)
 664{
 665        struct scsi_host_template *sht = sdev->host->hostt;
 666        struct scsi_device *tmp_sdev;
 667
 668        if (!sht->track_queue_depth ||
 669            sdev->queue_depth >= sdev->max_queue_depth)
 670                return;
 671
 672        if (time_before(jiffies,
 673            sdev->last_queue_ramp_up + sdev->queue_ramp_up_period))
 674                return;
 675
 676        if (time_before(jiffies,
 677            sdev->last_queue_full_time + sdev->queue_ramp_up_period))
 678                return;
 679
 680        /*
 681         * Walk all devices of a target and do
 682         * ramp up on them.
 683         */
 684        shost_for_each_device(tmp_sdev, sdev->host) {
 685                if (tmp_sdev->channel != sdev->channel ||
 686                    tmp_sdev->id != sdev->id ||
 687                    tmp_sdev->queue_depth == sdev->max_queue_depth)
 688                        continue;
 689
 690                scsi_change_queue_depth(tmp_sdev, tmp_sdev->queue_depth + 1);
 691                sdev->last_queue_ramp_up = jiffies;
 692        }
 693}
 694
 695static void scsi_handle_queue_full(struct scsi_device *sdev)
 696{
 697        struct scsi_host_template *sht = sdev->host->hostt;
 698        struct scsi_device *tmp_sdev;
 699
 700        if (!sht->track_queue_depth)
 701                return;
 702
 703        shost_for_each_device(tmp_sdev, sdev->host) {
 704                if (tmp_sdev->channel != sdev->channel ||
 705                    tmp_sdev->id != sdev->id)
 706                        continue;
 707                /*
 708                 * We do not know the number of commands that were at
 709                 * the device when we got the queue full so we start
 710                 * from the highest possible value and work our way down.
 711                 */
 712                scsi_track_queue_full(tmp_sdev, tmp_sdev->queue_depth - 1);
 713        }
 714}
 715
 716/**
 717 * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD.
 718 * @scmd:       SCSI cmd to examine.
 719 *
 720 * Notes:
 721 *    This is *only* called when we are examining the status of commands
 722 *    queued during error recovery.  the main difference here is that we
 723 *    don't allow for the possibility of retries here, and we are a lot
 724 *    more restrictive about what we consider acceptable.
 725 */
 726static enum scsi_disposition scsi_eh_completed_normally(struct scsi_cmnd *scmd)
 727{
 728        /*
 729         * first check the host byte, to see if there is anything in there
 730         * that would indicate what we need to do.
 731         */
 732        if (host_byte(scmd->result) == DID_RESET) {
 733                /*
 734                 * rats.  we are already in the error handler, so we now
 735                 * get to try and figure out what to do next.  if the sense
 736                 * is valid, we have a pretty good idea of what to do.
 737                 * if not, we mark it as FAILED.
 738                 */
 739                return scsi_check_sense(scmd);
 740        }
 741        if (host_byte(scmd->result) != DID_OK)
 742                return FAILED;
 743
 744        /*
 745         * next, check the message byte.
 746         */
 747        if (msg_byte(scmd->result) != COMMAND_COMPLETE)
 748                return FAILED;
 749
 750        /*
 751         * now, check the status byte to see if this indicates
 752         * anything special.
 753         */
 754        switch (status_byte(scmd->result)) {
 755        case GOOD:
 756                scsi_handle_queue_ramp_up(scmd->device);
 757                fallthrough;
 758        case COMMAND_TERMINATED:
 759                return SUCCESS;
 760        case CHECK_CONDITION:
 761                return scsi_check_sense(scmd);
 762        case CONDITION_GOOD:
 763        case INTERMEDIATE_GOOD:
 764        case INTERMEDIATE_C_GOOD:
 765                /*
 766                 * who knows?  FIXME(eric)
 767                 */
 768                return SUCCESS;
 769        case RESERVATION_CONFLICT:
 770                if (scmd->cmnd[0] == TEST_UNIT_READY)
 771                        /* it is a success, we probed the device and
 772                         * found it */
 773                        return SUCCESS;
 774                /* otherwise, we failed to send the command */
 775                return FAILED;
 776        case QUEUE_FULL:
 777                scsi_handle_queue_full(scmd->device);
 778                fallthrough;
 779        case BUSY:
 780                return NEEDS_RETRY;
 781        default:
 782                return FAILED;
 783        }
 784        return FAILED;
 785}
 786
 787/**
 788 * scsi_eh_done - Completion function for error handling.
 789 * @scmd:       Cmd that is done.
 790 */
 791static void scsi_eh_done(struct scsi_cmnd *scmd)
 792{
 793        struct completion *eh_action;
 794
 795        SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
 796                        "%s result: %x\n", __func__, scmd->result));
 797
 798        eh_action = scmd->device->host->eh_action;
 799        if (eh_action)
 800                complete(eh_action);
 801}
 802
 803/**
 804 * scsi_try_host_reset - ask host adapter to reset itself
 805 * @scmd:       SCSI cmd to send host reset.
 806 */
 807static enum scsi_disposition scsi_try_host_reset(struct scsi_cmnd *scmd)
 808{
 809        unsigned long flags;
 810        enum scsi_disposition rtn;
 811        struct Scsi_Host *host = scmd->device->host;
 812        struct scsi_host_template *hostt = host->hostt;
 813
 814        SCSI_LOG_ERROR_RECOVERY(3,
 815                shost_printk(KERN_INFO, host, "Snd Host RST\n"));
 816
 817        if (!hostt->eh_host_reset_handler)
 818                return FAILED;
 819
 820        rtn = hostt->eh_host_reset_handler(scmd);
 821
 822        if (rtn == SUCCESS) {
 823                if (!hostt->skip_settle_delay)
 824                        ssleep(HOST_RESET_SETTLE_TIME);
 825                spin_lock_irqsave(host->host_lock, flags);
 826                scsi_report_bus_reset(host, scmd_channel(scmd));
 827                spin_unlock_irqrestore(host->host_lock, flags);
 828        }
 829
 830        return rtn;
 831}
 832
 833/**
 834 * scsi_try_bus_reset - ask host to perform a bus reset
 835 * @scmd:       SCSI cmd to send bus reset.
 836 */
 837static enum scsi_disposition scsi_try_bus_reset(struct scsi_cmnd *scmd)
 838{
 839        unsigned long flags;
 840        enum scsi_disposition rtn;
 841        struct Scsi_Host *host = scmd->device->host;
 842        struct scsi_host_template *hostt = host->hostt;
 843
 844        SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
 845                "%s: Snd Bus RST\n", __func__));
 846
 847        if (!hostt->eh_bus_reset_handler)
 848                return FAILED;
 849
 850        rtn = hostt->eh_bus_reset_handler(scmd);
 851
 852        if (rtn == SUCCESS) {
 853                if (!hostt->skip_settle_delay)
 854                        ssleep(BUS_RESET_SETTLE_TIME);
 855                spin_lock_irqsave(host->host_lock, flags);
 856                scsi_report_bus_reset(host, scmd_channel(scmd));
 857                spin_unlock_irqrestore(host->host_lock, flags);
 858        }
 859
 860        return rtn;
 861}
 862
 863static void __scsi_report_device_reset(struct scsi_device *sdev, void *data)
 864{
 865        sdev->was_reset = 1;
 866        sdev->expecting_cc_ua = 1;
 867}
 868
 869/**
 870 * scsi_try_target_reset - Ask host to perform a target reset
 871 * @scmd:       SCSI cmd used to send a target reset
 872 *
 873 * Notes:
 874 *    There is no timeout for this operation.  if this operation is
 875 *    unreliable for a given host, then the host itself needs to put a
 876 *    timer on it, and set the host back to a consistent state prior to
 877 *    returning.
 878 */
 879static enum scsi_disposition scsi_try_target_reset(struct scsi_cmnd *scmd)
 880{
 881        unsigned long flags;
 882        enum scsi_disposition rtn;
 883        struct Scsi_Host *host = scmd->device->host;
 884        struct scsi_host_template *hostt = host->hostt;
 885
 886        if (!hostt->eh_target_reset_handler)
 887                return FAILED;
 888
 889        rtn = hostt->eh_target_reset_handler(scmd);
 890        if (rtn == SUCCESS) {
 891                spin_lock_irqsave(host->host_lock, flags);
 892                __starget_for_each_device(scsi_target(scmd->device), NULL,
 893                                          __scsi_report_device_reset);
 894                spin_unlock_irqrestore(host->host_lock, flags);
 895        }
 896
 897        return rtn;
 898}
 899
 900/**
 901 * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
 902 * @scmd:       SCSI cmd used to send BDR
 903 *
 904 * Notes:
 905 *    There is no timeout for this operation.  if this operation is
 906 *    unreliable for a given host, then the host itself needs to put a
 907 *    timer on it, and set the host back to a consistent state prior to
 908 *    returning.
 909 */
 910static enum scsi_disposition scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
 911{
 912        enum scsi_disposition rtn;
 913        struct scsi_host_template *hostt = scmd->device->host->hostt;
 914
 915        if (!hostt->eh_device_reset_handler)
 916                return FAILED;
 917
 918        rtn = hostt->eh_device_reset_handler(scmd);
 919        if (rtn == SUCCESS)
 920                __scsi_report_device_reset(scmd->device, NULL);
 921        return rtn;
 922}
 923
 924/**
 925 * scsi_try_to_abort_cmd - Ask host to abort a SCSI command
 926 * @hostt:      SCSI driver host template
 927 * @scmd:       SCSI cmd used to send a target reset
 928 *
 929 * Return value:
 930 *      SUCCESS, FAILED, or FAST_IO_FAIL
 931 *
 932 * Notes:
 933 *    SUCCESS does not necessarily indicate that the command
 934 *    has been aborted; it only indicates that the LLDDs
 935 *    has cleared all references to that command.
 936 *    LLDDs should return FAILED only if an abort was required
 937 *    but could not be executed. LLDDs should return FAST_IO_FAIL
 938 *    if the device is temporarily unavailable (eg due to a
 939 *    link down on FibreChannel)
 940 */
 941static enum scsi_disposition
 942scsi_try_to_abort_cmd(struct scsi_host_template *hostt, struct scsi_cmnd *scmd)
 943{
 944        if (!hostt->eh_abort_handler)
 945                return FAILED;
 946
 947        return hostt->eh_abort_handler(scmd);
 948}
 949
 950static void scsi_abort_eh_cmnd(struct scsi_cmnd *scmd)
 951{
 952        if (scsi_try_to_abort_cmd(scmd->device->host->hostt, scmd) != SUCCESS)
 953                if (scsi_try_bus_device_reset(scmd) != SUCCESS)
 954                        if (scsi_try_target_reset(scmd) != SUCCESS)
 955                                if (scsi_try_bus_reset(scmd) != SUCCESS)
 956                                        scsi_try_host_reset(scmd);
 957}
 958
 959/**
 960 * scsi_eh_prep_cmnd  - Save a scsi command info as part of error recovery
 961 * @scmd:       SCSI command structure to hijack
 962 * @ses:        structure to save restore information
 963 * @cmnd:       CDB to send. Can be NULL if no new cmnd is needed
 964 * @cmnd_size:  size in bytes of @cmnd (must be <= BLK_MAX_CDB)
 965 * @sense_bytes: size of sense data to copy. or 0 (if != 0 @cmnd is ignored)
 966 *
 967 * This function is used to save a scsi command information before re-execution
 968 * as part of the error recovery process.  If @sense_bytes is 0 the command
 969 * sent must be one that does not transfer any data.  If @sense_bytes != 0
 970 * @cmnd is ignored and this functions sets up a REQUEST_SENSE command
 971 * and cmnd buffers to read @sense_bytes into @scmd->sense_buffer.
 972 */
 973void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses,
 974                        unsigned char *cmnd, int cmnd_size, unsigned sense_bytes)
 975{
 976        struct scsi_device *sdev = scmd->device;
 977
 978        /*
 979         * We need saved copies of a number of fields - this is because
 980         * error handling may need to overwrite these with different values
 981         * to run different commands, and once error handling is complete,
 982         * we will need to restore these values prior to running the actual
 983         * command.
 984         */
 985        ses->cmd_len = scmd->cmd_len;
 986        ses->cmnd = scmd->cmnd;
 987        ses->data_direction = scmd->sc_data_direction;
 988        ses->sdb = scmd->sdb;
 989        ses->result = scmd->result;
 990        ses->resid_len = scmd->req.resid_len;
 991        ses->underflow = scmd->underflow;
 992        ses->prot_op = scmd->prot_op;
 993        ses->eh_eflags = scmd->eh_eflags;
 994
 995        scmd->prot_op = SCSI_PROT_NORMAL;
 996        scmd->eh_eflags = 0;
 997        scmd->cmnd = ses->eh_cmnd;
 998        memset(scmd->cmnd, 0, BLK_MAX_CDB);
 999        memset(&scmd->sdb, 0, sizeof(scmd->sdb));
1000        scmd->result = 0;
1001        scmd->req.resid_len = 0;
1002
1003        if (sense_bytes) {
1004                scmd->sdb.length = min_t(unsigned, SCSI_SENSE_BUFFERSIZE,
1005                                         sense_bytes);
1006                sg_init_one(&ses->sense_sgl, scmd->sense_buffer,
1007                            scmd->sdb.length);
1008                scmd->sdb.table.sgl = &ses->sense_sgl;
1009                scmd->sc_data_direction = DMA_FROM_DEVICE;
1010                scmd->sdb.table.nents = scmd->sdb.table.orig_nents = 1;
1011                scmd->cmnd[0] = REQUEST_SENSE;
1012                scmd->cmnd[4] = scmd->sdb.length;
1013                scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
1014        } else {
1015                scmd->sc_data_direction = DMA_NONE;
1016                if (cmnd) {
1017                        BUG_ON(cmnd_size > BLK_MAX_CDB);
1018                        memcpy(scmd->cmnd, cmnd, cmnd_size);
1019                        scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
1020                }
1021        }
1022
1023        scmd->underflow = 0;
1024
1025        if (sdev->scsi_level <= SCSI_2 && sdev->scsi_level != SCSI_UNKNOWN)
1026                scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
1027                        (sdev->lun << 5 & 0xe0);
1028
1029        /*
1030         * Zero the sense buffer.  The scsi spec mandates that any
1031         * untransferred sense data should be interpreted as being zero.
1032         */
1033        memset(scmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
1034}
1035EXPORT_SYMBOL(scsi_eh_prep_cmnd);
1036
1037/**
1038 * scsi_eh_restore_cmnd  - Restore a scsi command info as part of error recovery
1039 * @scmd:       SCSI command structure to restore
1040 * @ses:        saved information from a coresponding call to scsi_eh_prep_cmnd
1041 *
1042 * Undo any damage done by above scsi_eh_prep_cmnd().
1043 */
1044void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct scsi_eh_save *ses)
1045{
1046        /*
1047         * Restore original data
1048         */
1049        scmd->cmd_len = ses->cmd_len;
1050        scmd->cmnd = ses->cmnd;
1051        scmd->sc_data_direction = ses->data_direction;
1052        scmd->sdb = ses->sdb;
1053        scmd->result = ses->result;
1054        scmd->req.resid_len = ses->resid_len;
1055        scmd->underflow = ses->underflow;
1056        scmd->prot_op = ses->prot_op;
1057        scmd->eh_eflags = ses->eh_eflags;
1058}
1059EXPORT_SYMBOL(scsi_eh_restore_cmnd);
1060
1061/**
1062 * scsi_send_eh_cmnd  - submit a scsi command as part of error recovery
1063 * @scmd:       SCSI command structure to hijack
1064 * @cmnd:       CDB to send
1065 * @cmnd_size:  size in bytes of @cmnd
1066 * @timeout:    timeout for this request
1067 * @sense_bytes: size of sense data to copy or 0
1068 *
1069 * This function is used to send a scsi command down to a target device
1070 * as part of the error recovery process. See also scsi_eh_prep_cmnd() above.
1071 *
1072 * Return value:
1073 *    SUCCESS or FAILED or NEEDS_RETRY
1074 */
1075static enum scsi_disposition scsi_send_eh_cmnd(struct scsi_cmnd *scmd,
1076        unsigned char *cmnd, int cmnd_size, int timeout, unsigned sense_bytes)
1077{
1078        struct scsi_device *sdev = scmd->device;
1079        struct Scsi_Host *shost = sdev->host;
1080        DECLARE_COMPLETION_ONSTACK(done);
1081        unsigned long timeleft = timeout, delay;
1082        struct scsi_eh_save ses;
1083        const unsigned long stall_for = msecs_to_jiffies(100);
1084        int rtn;
1085
1086retry:
1087        scsi_eh_prep_cmnd(scmd, &ses, cmnd, cmnd_size, sense_bytes);
1088        shost->eh_action = &done;
1089
1090        scsi_log_send(scmd);
1091        scmd->scsi_done = scsi_eh_done;
1092
1093        /*
1094         * Lock sdev->state_mutex to avoid that scsi_device_quiesce() can
1095         * change the SCSI device state after we have examined it and before
1096         * .queuecommand() is called.
1097         */
1098        mutex_lock(&sdev->state_mutex);
1099        while (sdev->sdev_state == SDEV_BLOCK && timeleft > 0) {
1100                mutex_unlock(&sdev->state_mutex);
1101                SCSI_LOG_ERROR_RECOVERY(5, sdev_printk(KERN_DEBUG, sdev,
1102                        "%s: state %d <> %d\n", __func__, sdev->sdev_state,
1103                        SDEV_BLOCK));
1104                delay = min(timeleft, stall_for);
1105                timeleft -= delay;
1106                msleep(jiffies_to_msecs(delay));
1107                mutex_lock(&sdev->state_mutex);
1108        }
1109        if (sdev->sdev_state != SDEV_BLOCK)
1110                rtn = shost->hostt->queuecommand(shost, scmd);
1111        else
1112                rtn = FAILED;
1113        mutex_unlock(&sdev->state_mutex);
1114
1115        if (rtn) {
1116                if (timeleft > stall_for) {
1117                        scsi_eh_restore_cmnd(scmd, &ses);
1118                        timeleft -= stall_for;
1119                        msleep(jiffies_to_msecs(stall_for));
1120                        goto retry;
1121                }
1122                /* signal not to enter either branch of the if () below */
1123                timeleft = 0;
1124                rtn = FAILED;
1125        } else {
1126                timeleft = wait_for_completion_timeout(&done, timeout);
1127                rtn = SUCCESS;
1128        }
1129
1130        shost->eh_action = NULL;
1131
1132        scsi_log_completion(scmd, rtn);
1133
1134        SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1135                        "%s timeleft: %ld\n",
1136                        __func__, timeleft));
1137
1138        /*
1139         * If there is time left scsi_eh_done got called, and we will examine
1140         * the actual status codes to see whether the command actually did
1141         * complete normally, else if we have a zero return and no time left,
1142         * the command must still be pending, so abort it and return FAILED.
1143         * If we never actually managed to issue the command, because
1144         * ->queuecommand() kept returning non zero, use the rtn = FAILED
1145         * value above (so don't execute either branch of the if)
1146         */
1147        if (timeleft) {
1148                rtn = scsi_eh_completed_normally(scmd);
1149                SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1150                        "%s: scsi_eh_completed_normally %x\n", __func__, rtn));
1151
1152                switch (rtn) {
1153                case SUCCESS:
1154                case NEEDS_RETRY:
1155                case FAILED:
1156                        break;
1157                case ADD_TO_MLQUEUE:
1158                        rtn = NEEDS_RETRY;
1159                        break;
1160                default:
1161                        rtn = FAILED;
1162                        break;
1163                }
1164        } else if (rtn != FAILED) {
1165                scsi_abort_eh_cmnd(scmd);
1166                rtn = FAILED;
1167        }
1168
1169        scsi_eh_restore_cmnd(scmd, &ses);
1170
1171        return rtn;
1172}
1173
1174/**
1175 * scsi_request_sense - Request sense data from a particular target.
1176 * @scmd:       SCSI cmd for request sense.
1177 *
1178 * Notes:
1179 *    Some hosts automatically obtain this information, others require
1180 *    that we obtain it on our own. This function will *not* return until
1181 *    the command either times out, or it completes.
1182 */
1183static enum scsi_disposition scsi_request_sense(struct scsi_cmnd *scmd)
1184{
1185        return scsi_send_eh_cmnd(scmd, NULL, 0, scmd->device->eh_timeout, ~0);
1186}
1187
1188static enum scsi_disposition
1189scsi_eh_action(struct scsi_cmnd *scmd, enum scsi_disposition rtn)
1190{
1191        if (!blk_rq_is_passthrough(scmd->request)) {
1192                struct scsi_driver *sdrv = scsi_cmd_to_driver(scmd);
1193                if (sdrv->eh_action)
1194                        rtn = sdrv->eh_action(scmd, rtn);
1195        }
1196        return rtn;
1197}
1198
1199/**
1200 * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
1201 * @scmd:       Original SCSI cmd that eh has finished.
1202 * @done_q:     Queue for processed commands.
1203 *
1204 * Notes:
1205 *    We don't want to use the normal command completion while we are are
1206 *    still handling errors - it may cause other commands to be queued,
1207 *    and that would disturb what we are doing.  Thus we really want to
1208 *    keep a list of pending commands for final completion, and once we
1209 *    are ready to leave error handling we handle completion for real.
1210 */
1211void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)
1212{
1213        list_move_tail(&scmd->eh_entry, done_q);
1214}
1215EXPORT_SYMBOL(scsi_eh_finish_cmd);
1216
1217/**
1218 * scsi_eh_get_sense - Get device sense data.
1219 * @work_q:     Queue of commands to process.
1220 * @done_q:     Queue of processed commands.
1221 *
1222 * Description:
1223 *    See if we need to request sense information.  if so, then get it
1224 *    now, so we have a better idea of what to do.
1225 *
1226 * Notes:
1227 *    This has the unfortunate side effect that if a shost adapter does
1228 *    not automatically request sense information, we end up shutting
1229 *    it down before we request it.
1230 *
1231 *    All drivers should request sense information internally these days,
1232 *    so for now all I have to say is tough noogies if you end up in here.
1233 *
1234 *    XXX: Long term this code should go away, but that needs an audit of
1235 *         all LLDDs first.
1236 */
1237int scsi_eh_get_sense(struct list_head *work_q,
1238                      struct list_head *done_q)
1239{
1240        struct scsi_cmnd *scmd, *next;
1241        struct Scsi_Host *shost;
1242        enum scsi_disposition rtn;
1243
1244        /*
1245         * If SCSI_EH_ABORT_SCHEDULED has been set, it is timeout IO,
1246         * should not get sense.
1247         */
1248        list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1249                if ((scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) ||
1250                    SCSI_SENSE_VALID(scmd))
1251                        continue;
1252
1253                shost = scmd->device->host;
1254                if (scsi_host_eh_past_deadline(shost)) {
1255                        SCSI_LOG_ERROR_RECOVERY(3,
1256                                scmd_printk(KERN_INFO, scmd,
1257                                            "%s: skip request sense, past eh deadline\n",
1258                                             current->comm));
1259                        break;
1260                }
1261                if (status_byte(scmd->result) != CHECK_CONDITION)
1262                        /*
1263                         * don't request sense if there's no check condition
1264                         * status because the error we're processing isn't one
1265                         * that has a sense code (and some devices get
1266                         * confused by sense requests out of the blue)
1267                         */
1268                        continue;
1269
1270                SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd,
1271                                                  "%s: requesting sense\n",
1272                                                  current->comm));
1273                rtn = scsi_request_sense(scmd);
1274                if (rtn != SUCCESS)
1275                        continue;
1276
1277                SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1278                        "sense requested, result %x\n", scmd->result));
1279                SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense(scmd));
1280
1281                rtn = scsi_decide_disposition(scmd);
1282
1283                /*
1284                 * if the result was normal, then just pass it along to the
1285                 * upper level.
1286                 */
1287                if (rtn == SUCCESS)
1288                        /*
1289                         * We don't want this command reissued, just finished
1290                         * with the sense data, so set retries to the max
1291                         * allowed to ensure it won't get reissued. If the user
1292                         * has requested infinite retries, we also want to
1293                         * finish this command, so force completion by setting
1294                         * retries and allowed to the same value.
1295                         */
1296                        if (scmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT)
1297                                scmd->retries = scmd->allowed = 1;
1298                        else
1299                                scmd->retries = scmd->allowed;
1300                else if (rtn != NEEDS_RETRY)
1301                        continue;
1302
1303                scsi_eh_finish_cmd(scmd, done_q);
1304        }
1305
1306        return list_empty(work_q);
1307}
1308EXPORT_SYMBOL_GPL(scsi_eh_get_sense);
1309
1310/**
1311 * scsi_eh_tur - Send TUR to device.
1312 * @scmd:       &scsi_cmnd to send TUR
1313 *
1314 * Return value:
1315 *    0 - Device is ready. 1 - Device NOT ready.
1316 */
1317static int scsi_eh_tur(struct scsi_cmnd *scmd)
1318{
1319        static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
1320        int retry_cnt = 1;
1321        enum scsi_disposition rtn;
1322
1323retry_tur:
1324        rtn = scsi_send_eh_cmnd(scmd, tur_command, 6,
1325                                scmd->device->eh_timeout, 0);
1326
1327        SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
1328                "%s return: %x\n", __func__, rtn));
1329
1330        switch (rtn) {
1331        case NEEDS_RETRY:
1332                if (retry_cnt--)
1333                        goto retry_tur;
1334                fallthrough;
1335        case SUCCESS:
1336                return 0;
1337        default:
1338                return 1;
1339        }
1340}
1341
1342/**
1343 * scsi_eh_test_devices - check if devices are responding from error recovery.
1344 * @cmd_list:   scsi commands in error recovery.
1345 * @work_q:     queue for commands which still need more error recovery
1346 * @done_q:     queue for commands which are finished
1347 * @try_stu:    boolean on if a STU command should be tried in addition to TUR.
1348 *
1349 * Decription:
1350 *    Tests if devices are in a working state.  Commands to devices now in
1351 *    a working state are sent to the done_q while commands to devices which
1352 *    are still failing to respond are returned to the work_q for more
1353 *    processing.
1354 **/
1355static int scsi_eh_test_devices(struct list_head *cmd_list,
1356                                struct list_head *work_q,
1357                                struct list_head *done_q, int try_stu)
1358{
1359        struct scsi_cmnd *scmd, *next;
1360        struct scsi_device *sdev;
1361        int finish_cmds;
1362
1363        while (!list_empty(cmd_list)) {
1364                scmd = list_entry(cmd_list->next, struct scsi_cmnd, eh_entry);
1365                sdev = scmd->device;
1366
1367                if (!try_stu) {
1368                        if (scsi_host_eh_past_deadline(sdev->host)) {
1369                                /* Push items back onto work_q */
1370                                list_splice_init(cmd_list, work_q);
1371                                SCSI_LOG_ERROR_RECOVERY(3,
1372                                        sdev_printk(KERN_INFO, sdev,
1373                                                    "%s: skip test device, past eh deadline",
1374                                                    current->comm));
1375                                break;
1376                        }
1377                }
1378
1379                finish_cmds = !scsi_device_online(scmd->device) ||
1380                        (try_stu && !scsi_eh_try_stu(scmd) &&
1381                         !scsi_eh_tur(scmd)) ||
1382                        !scsi_eh_tur(scmd);
1383
1384                list_for_each_entry_safe(scmd, next, cmd_list, eh_entry)
1385                        if (scmd->device == sdev) {
1386                                if (finish_cmds &&
1387                                    (try_stu ||
1388                                     scsi_eh_action(scmd, SUCCESS) == SUCCESS))
1389                                        scsi_eh_finish_cmd(scmd, done_q);
1390                                else
1391                                        list_move_tail(&scmd->eh_entry, work_q);
1392                        }
1393        }
1394        return list_empty(work_q);
1395}
1396
1397/**
1398 * scsi_eh_try_stu - Send START_UNIT to device.
1399 * @scmd:       &scsi_cmnd to send START_UNIT
1400 *
1401 * Return value:
1402 *    0 - Device is ready. 1 - Device NOT ready.
1403 */
1404static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
1405{
1406        static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
1407
1408        if (scmd->device->allow_restart) {
1409                int i;
1410                enum scsi_disposition rtn = NEEDS_RETRY;
1411
1412                for (i = 0; rtn == NEEDS_RETRY && i < 2; i++)
1413                        rtn = scsi_send_eh_cmnd(scmd, stu_command, 6, scmd->device->request_queue->rq_timeout, 0);
1414
1415                if (rtn == SUCCESS)
1416                        return 0;
1417        }
1418
1419        return 1;
1420}
1421
1422 /**
1423 * scsi_eh_stu - send START_UNIT if needed
1424 * @shost:      &scsi host being recovered.
1425 * @work_q:     &list_head for pending commands.
1426 * @done_q:     &list_head for processed commands.
1427 *
1428 * Notes:
1429 *    If commands are failing due to not ready, initializing command required,
1430 *      try revalidating the device, which will end up sending a start unit.
1431 */
1432static int scsi_eh_stu(struct Scsi_Host *shost,
1433                              struct list_head *work_q,
1434                              struct list_head *done_q)
1435{
1436        struct scsi_cmnd *scmd, *stu_scmd, *next;
1437        struct scsi_device *sdev;
1438
1439        shost_for_each_device(sdev, shost) {
1440                if (scsi_host_eh_past_deadline(shost)) {
1441                        SCSI_LOG_ERROR_RECOVERY(3,
1442                                sdev_printk(KERN_INFO, sdev,
1443                                            "%s: skip START_UNIT, past eh deadline\n",
1444                                            current->comm));
1445                        scsi_device_put(sdev);
1446                        break;
1447                }
1448                stu_scmd = NULL;
1449                list_for_each_entry(scmd, work_q, eh_entry)
1450                        if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
1451                            scsi_check_sense(scmd) == FAILED ) {
1452                                stu_scmd = scmd;
1453                                break;
1454                        }
1455
1456                if (!stu_scmd)
1457                        continue;
1458
1459                SCSI_LOG_ERROR_RECOVERY(3,
1460                        sdev_printk(KERN_INFO, sdev,
1461                                     "%s: Sending START_UNIT\n",
1462                                    current->comm));
1463
1464                if (!scsi_eh_try_stu(stu_scmd)) {
1465                        if (!scsi_device_online(sdev) ||
1466                            !scsi_eh_tur(stu_scmd)) {
1467                                list_for_each_entry_safe(scmd, next,
1468                                                          work_q, eh_entry) {
1469                                        if (scmd->device == sdev &&
1470                                            scsi_eh_action(scmd, SUCCESS) == SUCCESS)
1471                                                scsi_eh_finish_cmd(scmd, done_q);
1472                                }
1473                        }
1474                } else {
1475                        SCSI_LOG_ERROR_RECOVERY(3,
1476                                sdev_printk(KERN_INFO, sdev,
1477                                            "%s: START_UNIT failed\n",
1478                                            current->comm));
1479                }
1480        }
1481
1482        return list_empty(work_q);
1483}
1484
1485
1486/**
1487 * scsi_eh_bus_device_reset - send bdr if needed
1488 * @shost:      scsi host being recovered.
1489 * @work_q:     &list_head for pending commands.
1490 * @done_q:     &list_head for processed commands.
1491 *
1492 * Notes:
1493 *    Try a bus device reset.  Still, look to see whether we have multiple
1494 *    devices that are jammed or not - if we have multiple devices, it
1495 *    makes no sense to try bus_device_reset - we really would need to try
1496 *    a bus_reset instead.
1497 */
1498static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
1499                                    struct list_head *work_q,
1500                                    struct list_head *done_q)
1501{
1502        struct scsi_cmnd *scmd, *bdr_scmd, *next;
1503        struct scsi_device *sdev;
1504        enum scsi_disposition rtn;
1505
1506        shost_for_each_device(sdev, shost) {
1507                if (scsi_host_eh_past_deadline(shost)) {
1508                        SCSI_LOG_ERROR_RECOVERY(3,
1509                                sdev_printk(KERN_INFO, sdev,
1510                                            "%s: skip BDR, past eh deadline\n",
1511                                             current->comm));
1512                        scsi_device_put(sdev);
1513                        break;
1514                }
1515                bdr_scmd = NULL;
1516                list_for_each_entry(scmd, work_q, eh_entry)
1517                        if (scmd->device == sdev) {
1518                                bdr_scmd = scmd;
1519                                break;
1520                        }
1521
1522                if (!bdr_scmd)
1523                        continue;
1524
1525                SCSI_LOG_ERROR_RECOVERY(3,
1526                        sdev_printk(KERN_INFO, sdev,
1527                                     "%s: Sending BDR\n", current->comm));
1528                rtn = scsi_try_bus_device_reset(bdr_scmd);
1529                if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1530                        if (!scsi_device_online(sdev) ||
1531                            rtn == FAST_IO_FAIL ||
1532                            !scsi_eh_tur(bdr_scmd)) {
1533                                list_for_each_entry_safe(scmd, next,
1534                                                         work_q, eh_entry) {
1535                                        if (scmd->device == sdev &&
1536                                            scsi_eh_action(scmd, rtn) != FAILED)
1537                                                scsi_eh_finish_cmd(scmd,
1538                                                                   done_q);
1539                                }
1540                        }
1541                } else {
1542                        SCSI_LOG_ERROR_RECOVERY(3,
1543                                sdev_printk(KERN_INFO, sdev,
1544                                            "%s: BDR failed\n", current->comm));
1545                }
1546        }
1547
1548        return list_empty(work_q);
1549}
1550
1551/**
1552 * scsi_eh_target_reset - send target reset if needed
1553 * @shost:      scsi host being recovered.
1554 * @work_q:     &list_head for pending commands.
1555 * @done_q:     &list_head for processed commands.
1556 *
1557 * Notes:
1558 *    Try a target reset.
1559 */
1560static int scsi_eh_target_reset(struct Scsi_Host *shost,
1561                                struct list_head *work_q,
1562                                struct list_head *done_q)
1563{
1564        LIST_HEAD(tmp_list);
1565        LIST_HEAD(check_list);
1566
1567        list_splice_init(work_q, &tmp_list);
1568
1569        while (!list_empty(&tmp_list)) {
1570                struct scsi_cmnd *next, *scmd;
1571                enum scsi_disposition rtn;
1572                unsigned int id;
1573
1574                if (scsi_host_eh_past_deadline(shost)) {
1575                        /* push back on work queue for further processing */
1576                        list_splice_init(&check_list, work_q);
1577                        list_splice_init(&tmp_list, work_q);
1578                        SCSI_LOG_ERROR_RECOVERY(3,
1579                                shost_printk(KERN_INFO, shost,
1580                                            "%s: Skip target reset, past eh deadline\n",
1581                                             current->comm));
1582                        return list_empty(work_q);
1583                }
1584
1585                scmd = list_entry(tmp_list.next, struct scsi_cmnd, eh_entry);
1586                id = scmd_id(scmd);
1587
1588                SCSI_LOG_ERROR_RECOVERY(3,
1589                        shost_printk(KERN_INFO, shost,
1590                                     "%s: Sending target reset to target %d\n",
1591                                     current->comm, id));
1592                rtn = scsi_try_target_reset(scmd);
1593                if (rtn != SUCCESS && rtn != FAST_IO_FAIL)
1594                        SCSI_LOG_ERROR_RECOVERY(3,
1595                                shost_printk(KERN_INFO, shost,
1596                                             "%s: Target reset failed"
1597                                             " target: %d\n",
1598                                             current->comm, id));
1599                list_for_each_entry_safe(scmd, next, &tmp_list, eh_entry) {
1600                        if (scmd_id(scmd) != id)
1601                                continue;
1602
1603                        if (rtn == SUCCESS)
1604                                list_move_tail(&scmd->eh_entry, &check_list);
1605                        else if (rtn == FAST_IO_FAIL)
1606                                scsi_eh_finish_cmd(scmd, done_q);
1607                        else
1608                                /* push back on work queue for further processing */
1609                                list_move(&scmd->eh_entry, work_q);
1610                }
1611        }
1612
1613        return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1614}
1615
1616/**
1617 * scsi_eh_bus_reset - send a bus reset
1618 * @shost:      &scsi host being recovered.
1619 * @work_q:     &list_head for pending commands.
1620 * @done_q:     &list_head for processed commands.
1621 */
1622static int scsi_eh_bus_reset(struct Scsi_Host *shost,
1623                             struct list_head *work_q,
1624                             struct list_head *done_q)
1625{
1626        struct scsi_cmnd *scmd, *chan_scmd, *next;
1627        LIST_HEAD(check_list);
1628        unsigned int channel;
1629        enum scsi_disposition rtn;
1630
1631        /*
1632         * we really want to loop over the various channels, and do this on
1633         * a channel by channel basis.  we should also check to see if any
1634         * of the failed commands are on soft_reset devices, and if so, skip
1635         * the reset.
1636         */
1637
1638        for (channel = 0; channel <= shost->max_channel; channel++) {
1639                if (scsi_host_eh_past_deadline(shost)) {
1640                        list_splice_init(&check_list, work_q);
1641                        SCSI_LOG_ERROR_RECOVERY(3,
1642                                shost_printk(KERN_INFO, shost,
1643                                            "%s: skip BRST, past eh deadline\n",
1644                                             current->comm));
1645                        return list_empty(work_q);
1646                }
1647
1648                chan_scmd = NULL;
1649                list_for_each_entry(scmd, work_q, eh_entry) {
1650                        if (channel == scmd_channel(scmd)) {
1651                                chan_scmd = scmd;
1652                                break;
1653                                /*
1654                                 * FIXME add back in some support for
1655                                 * soft_reset devices.
1656                                 */
1657                        }
1658                }
1659
1660                if (!chan_scmd)
1661                        continue;
1662                SCSI_LOG_ERROR_RECOVERY(3,
1663                        shost_printk(KERN_INFO, shost,
1664                                     "%s: Sending BRST chan: %d\n",
1665                                     current->comm, channel));
1666                rtn = scsi_try_bus_reset(chan_scmd);
1667                if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1668                        list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1669                                if (channel == scmd_channel(scmd)) {
1670                                        if (rtn == FAST_IO_FAIL)
1671                                                scsi_eh_finish_cmd(scmd,
1672                                                                   done_q);
1673                                        else
1674                                                list_move_tail(&scmd->eh_entry,
1675                                                               &check_list);
1676                                }
1677                        }
1678                } else {
1679                        SCSI_LOG_ERROR_RECOVERY(3,
1680                                shost_printk(KERN_INFO, shost,
1681                                             "%s: BRST failed chan: %d\n",
1682                                             current->comm, channel));
1683                }
1684        }
1685        return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1686}
1687
1688/**
1689 * scsi_eh_host_reset - send a host reset
1690 * @shost:      host to be reset.
1691 * @work_q:     &list_head for pending commands.
1692 * @done_q:     &list_head for processed commands.
1693 */
1694static int scsi_eh_host_reset(struct Scsi_Host *shost,
1695                              struct list_head *work_q,
1696                              struct list_head *done_q)
1697{
1698        struct scsi_cmnd *scmd, *next;
1699        LIST_HEAD(check_list);
1700        enum scsi_disposition rtn;
1701
1702        if (!list_empty(work_q)) {
1703                scmd = list_entry(work_q->next,
1704                                  struct scsi_cmnd, eh_entry);
1705
1706                SCSI_LOG_ERROR_RECOVERY(3,
1707                        shost_printk(KERN_INFO, shost,
1708                                     "%s: Sending HRST\n",
1709                                     current->comm));
1710
1711                rtn = scsi_try_host_reset(scmd);
1712                if (rtn == SUCCESS) {
1713                        list_splice_init(work_q, &check_list);
1714                } else if (rtn == FAST_IO_FAIL) {
1715                        list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1716                                        scsi_eh_finish_cmd(scmd, done_q);
1717                        }
1718                } else {
1719                        SCSI_LOG_ERROR_RECOVERY(3,
1720                                shost_printk(KERN_INFO, shost,
1721                                             "%s: HRST failed\n",
1722                                             current->comm));
1723                }
1724        }
1725        return scsi_eh_test_devices(&check_list, work_q, done_q, 1);
1726}
1727
1728/**
1729 * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
1730 * @work_q:     &list_head for pending commands.
1731 * @done_q:     &list_head for processed commands.
1732 */
1733static void scsi_eh_offline_sdevs(struct list_head *work_q,
1734                                  struct list_head *done_q)
1735{
1736        struct scsi_cmnd *scmd, *next;
1737        struct scsi_device *sdev;
1738
1739        list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1740                sdev_printk(KERN_INFO, scmd->device, "Device offlined - "
1741                            "not ready after error recovery\n");
1742                sdev = scmd->device;
1743
1744                mutex_lock(&sdev->state_mutex);
1745                scsi_device_set_state(sdev, SDEV_OFFLINE);
1746                mutex_unlock(&sdev->state_mutex);
1747
1748                scsi_eh_finish_cmd(scmd, done_q);
1749        }
1750        return;
1751}
1752
1753/**
1754 * scsi_noretry_cmd - determine if command should be failed fast
1755 * @scmd:       SCSI cmd to examine.
1756 */
1757int scsi_noretry_cmd(struct scsi_cmnd *scmd)
1758{
1759        switch (host_byte(scmd->result)) {
1760        case DID_OK:
1761                break;
1762        case DID_TIME_OUT:
1763                goto check_type;
1764        case DID_BUS_BUSY:
1765                return (scmd->request->cmd_flags & REQ_FAILFAST_TRANSPORT);
1766        case DID_PARITY:
1767                return (scmd->request->cmd_flags & REQ_FAILFAST_DEV);
1768        case DID_ERROR:
1769                if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1770                    status_byte(scmd->result) == RESERVATION_CONFLICT)
1771                        return 0;
1772                fallthrough;
1773        case DID_SOFT_ERROR:
1774                return (scmd->request->cmd_flags & REQ_FAILFAST_DRIVER);
1775        }
1776
1777        if (status_byte(scmd->result) != CHECK_CONDITION)
1778                return 0;
1779
1780check_type:
1781        /*
1782         * assume caller has checked sense and determined
1783         * the check condition was retryable.
1784         */
1785        if (scmd->request->cmd_flags & REQ_FAILFAST_DEV ||
1786            blk_rq_is_passthrough(scmd->request))
1787                return 1;
1788
1789        return 0;
1790}
1791
1792/**
1793 * scsi_decide_disposition - Disposition a cmd on return from LLD.
1794 * @scmd:       SCSI cmd to examine.
1795 *
1796 * Notes:
1797 *    This is *only* called when we are examining the status after sending
1798 *    out the actual data command.  any commands that are queued for error
1799 *    recovery (e.g. test_unit_ready) do *not* come through here.
1800 *
1801 *    When this routine returns failed, it means the error handler thread
1802 *    is woken.  In cases where the error code indicates an error that
1803 *    doesn't require the error handler read (i.e. we don't need to
1804 *    abort/reset), this function should return SUCCESS.
1805 */
1806enum scsi_disposition scsi_decide_disposition(struct scsi_cmnd *scmd)
1807{
1808        enum scsi_disposition rtn;
1809
1810        /*
1811         * if the device is offline, then we clearly just pass the result back
1812         * up to the top level.
1813         */
1814        if (!scsi_device_online(scmd->device)) {
1815                SCSI_LOG_ERROR_RECOVERY(5, scmd_printk(KERN_INFO, scmd,
1816                        "%s: device offline - report as SUCCESS\n", __func__));
1817                return SUCCESS;
1818        }
1819
1820        /*
1821         * first check the host byte, to see if there is anything in there
1822         * that would indicate what we need to do.
1823         */
1824        switch (host_byte(scmd->result)) {
1825        case DID_PASSTHROUGH:
1826                /*
1827                 * no matter what, pass this through to the upper layer.
1828                 * nuke this special code so that it looks like we are saying
1829                 * did_ok.
1830                 */
1831                scmd->result &= 0xff00ffff;
1832                return SUCCESS;
1833        case DID_OK:
1834                /*
1835                 * looks good.  drop through, and check the next byte.
1836                 */
1837                break;
1838        case DID_ABORT:
1839                if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) {
1840                        set_host_byte(scmd, DID_TIME_OUT);
1841                        return SUCCESS;
1842                }
1843                fallthrough;
1844        case DID_NO_CONNECT:
1845        case DID_BAD_TARGET:
1846                /*
1847                 * note - this means that we just report the status back
1848                 * to the top level driver, not that we actually think
1849                 * that it indicates SUCCESS.
1850                 */
1851                return SUCCESS;
1852        case DID_SOFT_ERROR:
1853                /*
1854                 * when the low level driver returns did_soft_error,
1855                 * it is responsible for keeping an internal retry counter
1856                 * in order to avoid endless loops (db)
1857                 */
1858                goto maybe_retry;
1859        case DID_IMM_RETRY:
1860                return NEEDS_RETRY;
1861
1862        case DID_REQUEUE:
1863                return ADD_TO_MLQUEUE;
1864        case DID_TRANSPORT_DISRUPTED:
1865                /*
1866                 * LLD/transport was disrupted during processing of the IO.
1867                 * The transport class is now blocked/blocking,
1868                 * and the transport will decide what to do with the IO
1869                 * based on its timers and recovery capablilities if
1870                 * there are enough retries.
1871                 */
1872                goto maybe_retry;
1873        case DID_TRANSPORT_FAILFAST:
1874                /*
1875                 * The transport decided to failfast the IO (most likely
1876                 * the fast io fail tmo fired), so send IO directly upwards.
1877                 */
1878                return SUCCESS;
1879        case DID_TRANSPORT_MARGINAL:
1880                /*
1881                 * caller has decided not to do retries on
1882                 * abort success, so send IO directly upwards
1883                 */
1884                return SUCCESS;
1885        case DID_ERROR:
1886                if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1887                    status_byte(scmd->result) == RESERVATION_CONFLICT)
1888                        /*
1889                         * execute reservation conflict processing code
1890                         * lower down
1891                         */
1892                        break;
1893                fallthrough;
1894        case DID_BUS_BUSY:
1895        case DID_PARITY:
1896                goto maybe_retry;
1897        case DID_TIME_OUT:
1898                /*
1899                 * when we scan the bus, we get timeout messages for
1900                 * these commands if there is no device available.
1901                 * other hosts report did_no_connect for the same thing.
1902                 */
1903                if ((scmd->cmnd[0] == TEST_UNIT_READY ||
1904                     scmd->cmnd[0] == INQUIRY)) {
1905                        return SUCCESS;
1906                } else {
1907                        return FAILED;
1908                }
1909        case DID_RESET:
1910                return SUCCESS;
1911        default:
1912                return FAILED;
1913        }
1914
1915        /*
1916         * next, check the message byte.
1917         */
1918        if (msg_byte(scmd->result) != COMMAND_COMPLETE)
1919                return FAILED;
1920
1921        /*
1922         * check the status byte to see if this indicates anything special.
1923         */
1924        switch (status_byte(scmd->result)) {
1925        case QUEUE_FULL:
1926                scsi_handle_queue_full(scmd->device);
1927                /*
1928                 * the case of trying to send too many commands to a
1929                 * tagged queueing device.
1930                 */
1931                fallthrough;
1932        case BUSY:
1933                /*
1934                 * device can't talk to us at the moment.  Should only
1935                 * occur (SAM-3) when the task queue is empty, so will cause
1936                 * the empty queue handling to trigger a stall in the
1937                 * device.
1938                 */
1939                return ADD_TO_MLQUEUE;
1940        case GOOD:
1941                if (scmd->cmnd[0] == REPORT_LUNS)
1942                        scmd->device->sdev_target->expecting_lun_change = 0;
1943                scsi_handle_queue_ramp_up(scmd->device);
1944                fallthrough;
1945        case COMMAND_TERMINATED:
1946                return SUCCESS;
1947        case TASK_ABORTED:
1948                goto maybe_retry;
1949        case CHECK_CONDITION:
1950                rtn = scsi_check_sense(scmd);
1951                if (rtn == NEEDS_RETRY)
1952                        goto maybe_retry;
1953                /* if rtn == FAILED, we have no sense information;
1954                 * returning FAILED will wake the error handler thread
1955                 * to collect the sense and redo the decide
1956                 * disposition */
1957                return rtn;
1958        case CONDITION_GOOD:
1959        case INTERMEDIATE_GOOD:
1960        case INTERMEDIATE_C_GOOD:
1961        case ACA_ACTIVE:
1962                /*
1963                 * who knows?  FIXME(eric)
1964                 */
1965                return SUCCESS;
1966
1967        case RESERVATION_CONFLICT:
1968                sdev_printk(KERN_INFO, scmd->device,
1969                            "reservation conflict\n");
1970                set_host_byte(scmd, DID_NEXUS_FAILURE);
1971                return SUCCESS; /* causes immediate i/o error */
1972        default:
1973                return FAILED;
1974        }
1975        return FAILED;
1976
1977maybe_retry:
1978
1979        /* we requeue for retry because the error was retryable, and
1980         * the request was not marked fast fail.  Note that above,
1981         * even if the request is marked fast fail, we still requeue
1982         * for queue congestion conditions (QUEUE_FULL or BUSY) */
1983        if (scsi_cmd_retry_allowed(scmd) && !scsi_noretry_cmd(scmd)) {
1984                return NEEDS_RETRY;
1985        } else {
1986                /*
1987                 * no more retries - report this one back to upper level.
1988                 */
1989                return SUCCESS;
1990        }
1991}
1992
1993static void eh_lock_door_done(struct request *req, blk_status_t status)
1994{
1995        blk_put_request(req);
1996}
1997
1998/**
1999 * scsi_eh_lock_door - Prevent medium removal for the specified device
2000 * @sdev:       SCSI device to prevent medium removal
2001 *
2002 * Locking:
2003 *      We must be called from process context.
2004 *
2005 * Notes:
2006 *      We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
2007 *      head of the devices request queue, and continue.
2008 */
2009static void scsi_eh_lock_door(struct scsi_device *sdev)
2010{
2011        struct request *req;
2012        struct scsi_request *rq;
2013
2014        req = blk_get_request(sdev->request_queue, REQ_OP_SCSI_IN, 0);
2015        if (IS_ERR(req))
2016                return;
2017        rq = scsi_req(req);
2018
2019        rq->cmd[0] = ALLOW_MEDIUM_REMOVAL;
2020        rq->cmd[1] = 0;
2021        rq->cmd[2] = 0;
2022        rq->cmd[3] = 0;
2023        rq->cmd[4] = SCSI_REMOVAL_PREVENT;
2024        rq->cmd[5] = 0;
2025        rq->cmd_len = COMMAND_SIZE(rq->cmd[0]);
2026
2027        req->rq_flags |= RQF_QUIET;
2028        req->timeout = 10 * HZ;
2029        rq->retries = 5;
2030
2031        blk_execute_rq_nowait(NULL, req, 1, eh_lock_door_done);
2032}
2033
2034/**
2035 * scsi_restart_operations - restart io operations to the specified host.
2036 * @shost:      Host we are restarting.
2037 *
2038 * Notes:
2039 *    When we entered the error handler, we blocked all further i/o to
2040 *    this device.  we need to 'reverse' this process.
2041 */
2042static void scsi_restart_operations(struct Scsi_Host *shost)
2043{
2044        struct scsi_device *sdev;
2045        unsigned long flags;
2046
2047        /*
2048         * If the door was locked, we need to insert a door lock request
2049         * onto the head of the SCSI request queue for the device.  There
2050         * is no point trying to lock the door of an off-line device.
2051         */
2052        shost_for_each_device(sdev, shost) {
2053                if (scsi_device_online(sdev) && sdev->was_reset && sdev->locked) {
2054                        scsi_eh_lock_door(sdev);
2055                        sdev->was_reset = 0;
2056                }
2057        }
2058
2059        /*
2060         * next free up anything directly waiting upon the host.  this
2061         * will be requests for character device operations, and also for
2062         * ioctls to queued block devices.
2063         */
2064        SCSI_LOG_ERROR_RECOVERY(3,
2065                shost_printk(KERN_INFO, shost, "waking up host to restart\n"));
2066
2067        spin_lock_irqsave(shost->host_lock, flags);
2068        if (scsi_host_set_state(shost, SHOST_RUNNING))
2069                if (scsi_host_set_state(shost, SHOST_CANCEL))
2070                        BUG_ON(scsi_host_set_state(shost, SHOST_DEL));
2071        spin_unlock_irqrestore(shost->host_lock, flags);
2072
2073        wake_up(&shost->host_wait);
2074
2075        /*
2076         * finally we need to re-initiate requests that may be pending.  we will
2077         * have had everything blocked while error handling is taking place, and
2078         * now that error recovery is done, we will need to ensure that these
2079         * requests are started.
2080         */
2081        scsi_run_host_queues(shost);
2082
2083        /*
2084         * if eh is active and host_eh_scheduled is pending we need to re-run
2085         * recovery.  we do this check after scsi_run_host_queues() to allow
2086         * everything pent up since the last eh run a chance to make forward
2087         * progress before we sync again.  Either we'll immediately re-run
2088         * recovery or scsi_device_unbusy() will wake us again when these
2089         * pending commands complete.
2090         */
2091        spin_lock_irqsave(shost->host_lock, flags);
2092        if (shost->host_eh_scheduled)
2093                if (scsi_host_set_state(shost, SHOST_RECOVERY))
2094                        WARN_ON(scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY));
2095        spin_unlock_irqrestore(shost->host_lock, flags);
2096}
2097
2098/**
2099 * scsi_eh_ready_devs - check device ready state and recover if not.
2100 * @shost:      host to be recovered.
2101 * @work_q:     &list_head for pending commands.
2102 * @done_q:     &list_head for processed commands.
2103 */
2104void scsi_eh_ready_devs(struct Scsi_Host *shost,
2105                        struct list_head *work_q,
2106                        struct list_head *done_q)
2107{
2108        if (!scsi_eh_stu(shost, work_q, done_q))
2109                if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
2110                        if (!scsi_eh_target_reset(shost, work_q, done_q))
2111                                if (!scsi_eh_bus_reset(shost, work_q, done_q))
2112                                        if (!scsi_eh_host_reset(shost, work_q, done_q))
2113                                                scsi_eh_offline_sdevs(work_q,
2114                                                                      done_q);
2115}
2116EXPORT_SYMBOL_GPL(scsi_eh_ready_devs);
2117
2118/**
2119 * scsi_eh_flush_done_q - finish processed commands or retry them.
2120 * @done_q:     list_head of processed commands.
2121 */
2122void scsi_eh_flush_done_q(struct list_head *done_q)
2123{
2124        struct scsi_cmnd *scmd, *next;
2125
2126        list_for_each_entry_safe(scmd, next, done_q, eh_entry) {
2127                list_del_init(&scmd->eh_entry);
2128                if (scsi_device_online(scmd->device) &&
2129                    !scsi_noretry_cmd(scmd) && scsi_cmd_retry_allowed(scmd) &&
2130                        scsi_eh_should_retry_cmd(scmd)) {
2131                        SCSI_LOG_ERROR_RECOVERY(3,
2132                                scmd_printk(KERN_INFO, scmd,
2133                                             "%s: flush retry cmd\n",
2134                                             current->comm));
2135                                scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
2136                } else {
2137                        /*
2138                         * If just we got sense for the device (called
2139                         * scsi_eh_get_sense), scmd->result is already
2140                         * set, do not set DRIVER_TIMEOUT.
2141                         */
2142                        if (!scmd->result)
2143                                scmd->result |= (DRIVER_TIMEOUT << 24);
2144                        SCSI_LOG_ERROR_RECOVERY(3,
2145                                scmd_printk(KERN_INFO, scmd,
2146                                             "%s: flush finish cmd\n",
2147                                             current->comm));
2148                        scsi_finish_command(scmd);
2149                }
2150        }
2151}
2152EXPORT_SYMBOL(scsi_eh_flush_done_q);
2153
2154/**
2155 * scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
2156 * @shost:      Host to unjam.
2157 *
2158 * Notes:
2159 *    When we come in here, we *know* that all commands on the bus have
2160 *    either completed, failed or timed out.  we also know that no further
2161 *    commands are being sent to the host, so things are relatively quiet
2162 *    and we have freedom to fiddle with things as we wish.
2163 *
2164 *    This is only the *default* implementation.  it is possible for
2165 *    individual drivers to supply their own version of this function, and
2166 *    if the maintainer wishes to do this, it is strongly suggested that
2167 *    this function be taken as a template and modified.  this function
2168 *    was designed to correctly handle problems for about 95% of the
2169 *    different cases out there, and it should always provide at least a
2170 *    reasonable amount of error recovery.
2171 *
2172 *    Any command marked 'failed' or 'timeout' must eventually have
2173 *    scsi_finish_cmd() called for it.  we do all of the retry stuff
2174 *    here, so when we restart the host after we return it should have an
2175 *    empty queue.
2176 */
2177static void scsi_unjam_host(struct Scsi_Host *shost)
2178{
2179        unsigned long flags;
2180        LIST_HEAD(eh_work_q);
2181        LIST_HEAD(eh_done_q);
2182
2183        spin_lock_irqsave(shost->host_lock, flags);
2184        list_splice_init(&shost->eh_cmd_q, &eh_work_q);
2185        spin_unlock_irqrestore(shost->host_lock, flags);
2186
2187        SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
2188
2189        if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
2190                scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
2191
2192        spin_lock_irqsave(shost->host_lock, flags);
2193        if (shost->eh_deadline != -1)
2194                shost->last_reset = 0;
2195        spin_unlock_irqrestore(shost->host_lock, flags);
2196        scsi_eh_flush_done_q(&eh_done_q);
2197}
2198
2199/**
2200 * scsi_error_handler - SCSI error handler thread
2201 * @data:       Host for which we are running.
2202 *
2203 * Notes:
2204 *    This is the main error handling loop.  This is run as a kernel thread
2205 *    for every SCSI host and handles all error handling activity.
2206 */
2207int scsi_error_handler(void *data)
2208{
2209        struct Scsi_Host *shost = data;
2210
2211        /*
2212         * We use TASK_INTERRUPTIBLE so that the thread is not
2213         * counted against the load average as a running process.
2214         * We never actually get interrupted because kthread_run
2215         * disables signal delivery for the created thread.
2216         */
2217        while (true) {
2218                /*
2219                 * The sequence in kthread_stop() sets the stop flag first
2220                 * then wakes the process.  To avoid missed wakeups, the task
2221                 * should always be in a non running state before the stop
2222                 * flag is checked
2223                 */
2224                set_current_state(TASK_INTERRUPTIBLE);
2225                if (kthread_should_stop())
2226                        break;
2227
2228                if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||
2229                    shost->host_failed != scsi_host_busy(shost)) {
2230                        SCSI_LOG_ERROR_RECOVERY(1,
2231                                shost_printk(KERN_INFO, shost,
2232                                             "scsi_eh_%d: sleeping\n",
2233                                             shost->host_no));
2234                        schedule();
2235                        continue;
2236                }
2237
2238                __set_current_state(TASK_RUNNING);
2239                SCSI_LOG_ERROR_RECOVERY(1,
2240                        shost_printk(KERN_INFO, shost,
2241                                     "scsi_eh_%d: waking up %d/%d/%d\n",
2242                                     shost->host_no, shost->host_eh_scheduled,
2243                                     shost->host_failed,
2244                                     scsi_host_busy(shost)));
2245
2246                /*
2247                 * We have a host that is failing for some reason.  Figure out
2248                 * what we need to do to get it up and online again (if we can).
2249                 * If we fail, we end up taking the thing offline.
2250                 */
2251                if (!shost->eh_noresume && scsi_autopm_get_host(shost) != 0) {
2252                        SCSI_LOG_ERROR_RECOVERY(1,
2253                                shost_printk(KERN_ERR, shost,
2254                                             "scsi_eh_%d: unable to autoresume\n",
2255                                             shost->host_no));
2256                        continue;
2257                }
2258
2259                if (shost->transportt->eh_strategy_handler)
2260                        shost->transportt->eh_strategy_handler(shost);
2261                else
2262                        scsi_unjam_host(shost);
2263
2264                /* All scmds have been handled */
2265                shost->host_failed = 0;
2266
2267                /*
2268                 * Note - if the above fails completely, the action is to take
2269                 * individual devices offline and flush the queue of any
2270                 * outstanding requests that may have been pending.  When we
2271                 * restart, we restart any I/O to any other devices on the bus
2272                 * which are still online.
2273                 */
2274                scsi_restart_operations(shost);
2275                if (!shost->eh_noresume)
2276                        scsi_autopm_put_host(shost);
2277        }
2278        __set_current_state(TASK_RUNNING);
2279
2280        SCSI_LOG_ERROR_RECOVERY(1,
2281                shost_printk(KERN_INFO, shost,
2282                             "Error handler scsi_eh_%d exiting\n",
2283                             shost->host_no));
2284        shost->ehandler = NULL;
2285        return 0;
2286}
2287
2288/*
2289 * Function:    scsi_report_bus_reset()
2290 *
2291 * Purpose:     Utility function used by low-level drivers to report that
2292 *              they have observed a bus reset on the bus being handled.
2293 *
2294 * Arguments:   shost       - Host in question
2295 *              channel     - channel on which reset was observed.
2296 *
2297 * Returns:     Nothing
2298 *
2299 * Lock status: Host lock must be held.
2300 *
2301 * Notes:       This only needs to be called if the reset is one which
2302 *              originates from an unknown location.  Resets originated
2303 *              by the mid-level itself don't need to call this, but there
2304 *              should be no harm.
2305 *
2306 *              The main purpose of this is to make sure that a CHECK_CONDITION
2307 *              is properly treated.
2308 */
2309void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
2310{
2311        struct scsi_device *sdev;
2312
2313        __shost_for_each_device(sdev, shost) {
2314                if (channel == sdev_channel(sdev))
2315                        __scsi_report_device_reset(sdev, NULL);
2316        }
2317}
2318EXPORT_SYMBOL(scsi_report_bus_reset);
2319
2320/*
2321 * Function:    scsi_report_device_reset()
2322 *
2323 * Purpose:     Utility function used by low-level drivers to report that
2324 *              they have observed a device reset on the device being handled.
2325 *
2326 * Arguments:   shost       - Host in question
2327 *              channel     - channel on which reset was observed
2328 *              target      - target on which reset was observed
2329 *
2330 * Returns:     Nothing
2331 *
2332 * Lock status: Host lock must be held
2333 *
2334 * Notes:       This only needs to be called if the reset is one which
2335 *              originates from an unknown location.  Resets originated
2336 *              by the mid-level itself don't need to call this, but there
2337 *              should be no harm.
2338 *
2339 *              The main purpose of this is to make sure that a CHECK_CONDITION
2340 *              is properly treated.
2341 */
2342void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
2343{
2344        struct scsi_device *sdev;
2345
2346        __shost_for_each_device(sdev, shost) {
2347                if (channel == sdev_channel(sdev) &&
2348                    target == sdev_id(sdev))
2349                        __scsi_report_device_reset(sdev, NULL);
2350        }
2351}
2352EXPORT_SYMBOL(scsi_report_device_reset);
2353
2354static void
2355scsi_reset_provider_done_command(struct scsi_cmnd *scmd)
2356{
2357}
2358
2359/**
2360 * scsi_ioctl_reset: explicitly reset a host/bus/target/device
2361 * @dev:        scsi_device to operate on
2362 * @arg:        reset type (see sg.h)
2363 */
2364int
2365scsi_ioctl_reset(struct scsi_device *dev, int __user *arg)
2366{
2367        struct scsi_cmnd *scmd;
2368        struct Scsi_Host *shost = dev->host;
2369        struct request *rq;
2370        unsigned long flags;
2371        int error = 0, val;
2372        enum scsi_disposition rtn;
2373
2374        if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2375                return -EACCES;
2376
2377        error = get_user(val, arg);
2378        if (error)
2379                return error;
2380
2381        if (scsi_autopm_get_host(shost) < 0)
2382                return -EIO;
2383
2384        error = -EIO;
2385        rq = kzalloc(sizeof(struct request) + sizeof(struct scsi_cmnd) +
2386                        shost->hostt->cmd_size, GFP_KERNEL);
2387        if (!rq)
2388                goto out_put_autopm_host;
2389        blk_rq_init(NULL, rq);
2390
2391        scmd = (struct scsi_cmnd *)(rq + 1);
2392        scsi_init_command(dev, scmd);
2393        scmd->request = rq;
2394        scmd->cmnd = scsi_req(rq)->cmd;
2395
2396        scmd->scsi_done         = scsi_reset_provider_done_command;
2397        memset(&scmd->sdb, 0, sizeof(scmd->sdb));
2398
2399        scmd->cmd_len                   = 0;
2400
2401        scmd->sc_data_direction         = DMA_BIDIRECTIONAL;
2402
2403        spin_lock_irqsave(shost->host_lock, flags);
2404        shost->tmf_in_progress = 1;
2405        spin_unlock_irqrestore(shost->host_lock, flags);
2406
2407        switch (val & ~SG_SCSI_RESET_NO_ESCALATE) {
2408        case SG_SCSI_RESET_NOTHING:
2409                rtn = SUCCESS;
2410                break;
2411        case SG_SCSI_RESET_DEVICE:
2412                rtn = scsi_try_bus_device_reset(scmd);
2413                if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
2414                        break;
2415                fallthrough;
2416        case SG_SCSI_RESET_TARGET:
2417                rtn = scsi_try_target_reset(scmd);
2418                if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
2419                        break;
2420                fallthrough;
2421        case SG_SCSI_RESET_BUS:
2422                rtn = scsi_try_bus_reset(scmd);
2423                if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
2424                        break;
2425                fallthrough;
2426        case SG_SCSI_RESET_HOST:
2427                rtn = scsi_try_host_reset(scmd);
2428                if (rtn == SUCCESS)
2429                        break;
2430                fallthrough;
2431        default:
2432                rtn = FAILED;
2433                break;
2434        }
2435
2436        error = (rtn == SUCCESS) ? 0 : -EIO;
2437
2438        spin_lock_irqsave(shost->host_lock, flags);
2439        shost->tmf_in_progress = 0;
2440        spin_unlock_irqrestore(shost->host_lock, flags);
2441
2442        /*
2443         * be sure to wake up anyone who was sleeping or had their queue
2444         * suspended while we performed the TMF.
2445         */
2446        SCSI_LOG_ERROR_RECOVERY(3,
2447                shost_printk(KERN_INFO, shost,
2448                             "waking up host to restart after TMF\n"));
2449
2450        wake_up(&shost->host_wait);
2451        scsi_run_host_queues(shost);
2452
2453        kfree(rq);
2454
2455out_put_autopm_host:
2456        scsi_autopm_put_host(shost);
2457        return error;
2458}
2459
2460bool scsi_command_normalize_sense(const struct scsi_cmnd *cmd,
2461                                  struct scsi_sense_hdr *sshdr)
2462{
2463        return scsi_normalize_sense(cmd->sense_buffer,
2464                        SCSI_SENSE_BUFFERSIZE, sshdr);
2465}
2466EXPORT_SYMBOL(scsi_command_normalize_sense);
2467
2468/**
2469 * scsi_get_sense_info_fld - get information field from sense data (either fixed or descriptor format)
2470 * @sense_buffer:       byte array of sense data
2471 * @sb_len:             number of valid bytes in sense_buffer
2472 * @info_out:           pointer to 64 integer where 8 or 4 byte information
2473 *                      field will be placed if found.
2474 *
2475 * Return value:
2476 *      true if information field found, false if not found.
2477 */
2478bool scsi_get_sense_info_fld(const u8 *sense_buffer, int sb_len,
2479                             u64 *info_out)
2480{
2481        const u8 * ucp;
2482
2483        if (sb_len < 7)
2484                return false;
2485        switch (sense_buffer[0] & 0x7f) {
2486        case 0x70:
2487        case 0x71:
2488                if (sense_buffer[0] & 0x80) {
2489                        *info_out = get_unaligned_be32(&sense_buffer[3]);
2490                        return true;
2491                }
2492                return false;
2493        case 0x72:
2494        case 0x73:
2495                ucp = scsi_sense_desc_find(sense_buffer, sb_len,
2496                                           0 /* info desc */);
2497                if (ucp && (0xa == ucp[1])) {
2498                        *info_out = get_unaligned_be64(&ucp[4]);
2499                        return true;
2500                }
2501                return false;
2502        default:
2503                return false;
2504        }
2505}
2506EXPORT_SYMBOL(scsi_get_sense_info_fld);
2507