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