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