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_driver *sdrv = scsi_cmd_to_driver(scmd);
 793	struct Scsi_Host *shost = sdev->host;
 794	DECLARE_COMPLETION_ONSTACK(done);
 795	unsigned long timeleft;
 796	struct scsi_eh_save ses;
 
 797	int rtn;
 798
 
 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	shost->hostt->queuecommand(shost, scmd);
 805
 806	timeleft = wait_for_completion_timeout(&done, timeout);
 
 
 
 
 
 
 
 
 
 
 
 807
 808	shost->eh_action = NULL;
 809
 810	scsi_log_completion(scmd, SUCCESS);
 811
 812	SCSI_LOG_ERROR_RECOVERY(3,
 813		printk("%s: scmd: %p, timeleft: %ld\n",
 814			__func__, scmd, timeleft));
 815
 816	/*
 817	 * If there is time left scsi_eh_done got called, and we will
 818	 * examine the actual status codes to see whether the command
 819	 * actually did complete normally, else tell the host to forget
 820	 * about this command.
 
 
 
 821	 */
 822	if (timeleft) {
 823		rtn = scsi_eh_completed_normally(scmd);
 824		SCSI_LOG_ERROR_RECOVERY(3,
 825			printk("%s: scsi_eh_completed_normally %x\n",
 826			       __func__, rtn));
 827
 828		switch (rtn) {
 829		case SUCCESS:
 830		case NEEDS_RETRY:
 831		case FAILED:
 832		case TARGET_ERROR:
 833			break;
 834		case ADD_TO_MLQUEUE:
 835			rtn = NEEDS_RETRY;
 836			break;
 837		default:
 838			rtn = FAILED;
 839			break;
 840		}
 841	} else {
 842		scsi_abort_eh_cmnd(scmd);
 843		rtn = FAILED;
 844	}
 845
 846	scsi_eh_restore_cmnd(scmd, &ses);
 847
 848	if (sdrv && sdrv->eh_action)
 849		rtn = sdrv->eh_action(scmd, cmnd, cmnd_size, rtn);
 850
 851	return rtn;
 852}
 853
 854/**
 855 * scsi_request_sense - Request sense data from a particular target.
 856 * @scmd:	SCSI cmd for request sense.
 857 *
 858 * Notes:
 859 *    Some hosts automatically obtain this information, others require
 860 *    that we obtain it on our own. This function will *not* return until
 861 *    the command either times out, or it completes.
 862 */
 863static int scsi_request_sense(struct scsi_cmnd *scmd)
 864{
 865	return scsi_send_eh_cmnd(scmd, NULL, 0, SENSE_TIMEOUT, ~0);
 
 
 
 
 
 
 
 
 
 
 866}
 867
 868/**
 869 * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
 870 * @scmd:	Original SCSI cmd that eh has finished.
 871 * @done_q:	Queue for processed commands.
 872 *
 873 * Notes:
 874 *    We don't want to use the normal command completion while we are are
 875 *    still handling errors - it may cause other commands to be queued,
 876 *    and that would disturb what we are doing.  Thus we really want to
 877 *    keep a list of pending commands for final completion, and once we
 878 *    are ready to leave error handling we handle completion for real.
 879 */
 880void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)
 881{
 882	scmd->device->host->host_failed--;
 883	scmd->eh_eflags = 0;
 884	list_move_tail(&scmd->eh_entry, done_q);
 885}
 886EXPORT_SYMBOL(scsi_eh_finish_cmd);
 887
 888/**
 889 * scsi_eh_get_sense - Get device sense data.
 890 * @work_q:	Queue of commands to process.
 891 * @done_q:	Queue of processed commands.
 892 *
 893 * Description:
 894 *    See if we need to request sense information.  if so, then get it
 895 *    now, so we have a better idea of what to do.
 896 *
 897 * Notes:
 898 *    This has the unfortunate side effect that if a shost adapter does
 899 *    not automatically request sense information, we end up shutting
 900 *    it down before we request it.
 901 *
 902 *    All drivers should request sense information internally these days,
 903 *    so for now all I have to say is tough noogies if you end up in here.
 904 *
 905 *    XXX: Long term this code should go away, but that needs an audit of
 906 *         all LLDDs first.
 907 */
 908int scsi_eh_get_sense(struct list_head *work_q,
 909		      struct list_head *done_q)
 910{
 911	struct scsi_cmnd *scmd, *next;
 
 912	int rtn;
 913
 914	list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
 915		if ((scmd->eh_eflags & SCSI_EH_CANCEL_CMD) ||
 916		    SCSI_SENSE_VALID(scmd))
 917			continue;
 918
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 919		SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd,
 920						  "%s: requesting sense\n",
 921						  current->comm));
 922		rtn = scsi_request_sense(scmd);
 923		if (rtn != SUCCESS)
 924			continue;
 925
 926		SCSI_LOG_ERROR_RECOVERY(3, printk("sense requested for %p"
 927						  " result %x\n", scmd,
 928						  scmd->result));
 929		SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense("bh", scmd));
 930
 931		rtn = scsi_decide_disposition(scmd);
 932
 933		/*
 934		 * if the result was normal, then just pass it along to the
 935		 * upper level.
 936		 */
 937		if (rtn == SUCCESS)
 938			/* we don't want this command reissued, just
 939			 * finished with the sense data, so set
 940			 * retries to the max allowed to ensure it
 941			 * won't get reissued */
 942			scmd->retries = scmd->allowed;
 943		else if (rtn != NEEDS_RETRY)
 944			continue;
 945
 946		scsi_eh_finish_cmd(scmd, done_q);
 947	}
 948
 949	return list_empty(work_q);
 950}
 951EXPORT_SYMBOL_GPL(scsi_eh_get_sense);
 952
 953/**
 954 * scsi_eh_tur - Send TUR to device.
 955 * @scmd:	&scsi_cmnd to send TUR
 956 *
 957 * Return value:
 958 *    0 - Device is ready. 1 - Device NOT ready.
 959 */
 960static int scsi_eh_tur(struct scsi_cmnd *scmd)
 961{
 962	static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
 963	int retry_cnt = 1, rtn;
 964
 965retry_tur:
 966	rtn = scsi_send_eh_cmnd(scmd, tur_command, 6, SENSE_TIMEOUT, 0);
 
 967
 968	SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
 969		__func__, scmd, rtn));
 970
 971	switch (rtn) {
 972	case NEEDS_RETRY:
 973		if (retry_cnt--)
 974			goto retry_tur;
 975		/*FALLTHRU*/
 976	case SUCCESS:
 977		return 0;
 978	default:
 979		return 1;
 980	}
 981}
 982
 983/**
 984 * scsi_eh_test_devices - check if devices are responding from error recovery.
 985 * @cmd_list:	scsi commands in error recovery.
 986 * @work_q:     queue for commands which still need more error recovery
 987 * @done_q:     queue for commands which are finished
 988 * @try_stu:    boolean on if a STU command should be tried in addition to TUR.
 989 *
 990 * Decription:
 991 *    Tests if devices are in a working state.  Commands to devices now in
 992 *    a working state are sent to the done_q while commands to devices which
 993 *    are still failing to respond are returned to the work_q for more
 994 *    processing.
 995 **/
 996static int scsi_eh_test_devices(struct list_head *cmd_list,
 997				struct list_head *work_q,
 998				struct list_head *done_q, int try_stu)
 999{
1000	struct scsi_cmnd *scmd, *next;
1001	struct scsi_device *sdev;
1002	int finish_cmds;
1003
1004	while (!list_empty(cmd_list)) {
1005		scmd = list_entry(cmd_list->next, struct scsi_cmnd, eh_entry);
1006		sdev = scmd->device;
1007
 
 
 
 
 
 
 
 
 
 
 
 
1008		finish_cmds = !scsi_device_online(scmd->device) ||
1009			(try_stu && !scsi_eh_try_stu(scmd) &&
1010			 !scsi_eh_tur(scmd)) ||
1011			!scsi_eh_tur(scmd);
1012
1013		list_for_each_entry_safe(scmd, next, cmd_list, eh_entry)
1014			if (scmd->device == sdev) {
1015				if (finish_cmds)
 
 
1016					scsi_eh_finish_cmd(scmd, done_q);
1017				else
1018					list_move_tail(&scmd->eh_entry, work_q);
1019			}
1020	}
1021	return list_empty(work_q);
1022}
1023
1024
1025/**
1026 * scsi_eh_abort_cmds - abort pending commands.
1027 * @work_q:	&list_head for pending commands.
1028 * @done_q:	&list_head for processed commands.
1029 *
1030 * Decription:
1031 *    Try and see whether or not it makes sense to try and abort the
1032 *    running command.  This only works out to be the case if we have one
1033 *    command that has timed out.  If the command simply failed, it makes
1034 *    no sense to try and abort the command, since as far as the shost
1035 *    adapter is concerned, it isn't running.
1036 */
1037static int scsi_eh_abort_cmds(struct list_head *work_q,
1038			      struct list_head *done_q)
1039{
1040	struct scsi_cmnd *scmd, *next;
1041	LIST_HEAD(check_list);
1042	int rtn;
 
1043
1044	list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1045		if (!(scmd->eh_eflags & SCSI_EH_CANCEL_CMD))
1046			continue;
 
 
 
 
 
 
 
 
 
1047		SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting cmd:"
1048						  "0x%p\n", current->comm,
1049						  scmd));
1050		rtn = scsi_try_to_abort_cmd(scmd->device->host->hostt, scmd);
1051		if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1052			scmd->eh_eflags &= ~SCSI_EH_CANCEL_CMD;
1053			if (rtn == FAST_IO_FAIL)
1054				scsi_eh_finish_cmd(scmd, done_q);
1055			else
1056				list_move_tail(&scmd->eh_entry, &check_list);
1057		} else
1058			SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting"
1059							  " cmd failed:"
1060							  "0x%p\n",
1061							  current->comm,
1062							  scmd));
 
 
 
 
 
 
 
 
1063	}
1064
1065	return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1066}
1067
1068/**
1069 * scsi_eh_try_stu - Send START_UNIT to device.
1070 * @scmd:	&scsi_cmnd to send START_UNIT
1071 *
1072 * Return value:
1073 *    0 - Device is ready. 1 - Device NOT ready.
1074 */
1075static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
1076{
1077	static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
1078
1079	if (scmd->device->allow_restart) {
1080		int i, rtn = NEEDS_RETRY;
1081
1082		for (i = 0; rtn == NEEDS_RETRY && i < 2; i++)
1083			rtn = scsi_send_eh_cmnd(scmd, stu_command, 6, scmd->device->request_queue->rq_timeout, 0);
1084
1085		if (rtn == SUCCESS)
1086			return 0;
1087	}
1088
1089	return 1;
1090}
1091
1092 /**
1093 * scsi_eh_stu - send START_UNIT if needed
1094 * @shost:	&scsi host being recovered.
1095 * @work_q:     &list_head for pending commands.
1096 * @done_q:	&list_head for processed commands.
1097 *
1098 * Notes:
1099 *    If commands are failing due to not ready, initializing command required,
1100 *	try revalidating the device, which will end up sending a start unit.
1101 */
1102static int scsi_eh_stu(struct Scsi_Host *shost,
1103			      struct list_head *work_q,
1104			      struct list_head *done_q)
1105{
1106	struct scsi_cmnd *scmd, *stu_scmd, *next;
1107	struct scsi_device *sdev;
1108
1109	shost_for_each_device(sdev, shost) {
 
 
 
 
 
 
 
1110		stu_scmd = NULL;
1111		list_for_each_entry(scmd, work_q, eh_entry)
1112			if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
1113			    scsi_check_sense(scmd) == FAILED ) {
1114				stu_scmd = scmd;
1115				break;
1116			}
1117
1118		if (!stu_scmd)
1119			continue;
1120
1121		SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending START_UNIT to sdev:"
1122						  " 0x%p\n", current->comm, sdev));
1123
1124		if (!scsi_eh_try_stu(stu_scmd)) {
1125			if (!scsi_device_online(sdev) ||
1126			    !scsi_eh_tur(stu_scmd)) {
1127				list_for_each_entry_safe(scmd, next,
1128							  work_q, eh_entry) {
1129					if (scmd->device == sdev)
 
1130						scsi_eh_finish_cmd(scmd, done_q);
1131				}
1132			}
1133		} else {
1134			SCSI_LOG_ERROR_RECOVERY(3,
1135						printk("%s: START_UNIT failed to sdev:"
1136						       " 0x%p\n", current->comm, sdev));
1137		}
1138	}
1139
1140	return list_empty(work_q);
1141}
1142
1143
1144/**
1145 * scsi_eh_bus_device_reset - send bdr if needed
1146 * @shost:	scsi host being recovered.
1147 * @work_q:     &list_head for pending commands.
1148 * @done_q:	&list_head for processed commands.
1149 *
1150 * Notes:
1151 *    Try a bus device reset.  Still, look to see whether we have multiple
1152 *    devices that are jammed or not - if we have multiple devices, it
1153 *    makes no sense to try bus_device_reset - we really would need to try
1154 *    a bus_reset instead.
1155 */
1156static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
1157				    struct list_head *work_q,
1158				    struct list_head *done_q)
1159{
1160	struct scsi_cmnd *scmd, *bdr_scmd, *next;
1161	struct scsi_device *sdev;
1162	int rtn;
1163
1164	shost_for_each_device(sdev, shost) {
 
 
 
 
 
 
 
1165		bdr_scmd = NULL;
1166		list_for_each_entry(scmd, work_q, eh_entry)
1167			if (scmd->device == sdev) {
1168				bdr_scmd = scmd;
1169				break;
1170			}
1171
1172		if (!bdr_scmd)
1173			continue;
1174
1175		SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BDR sdev:"
1176						  " 0x%p\n", current->comm,
1177						  sdev));
1178		rtn = scsi_try_bus_device_reset(bdr_scmd);
1179		if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1180			if (!scsi_device_online(sdev) ||
1181			    rtn == FAST_IO_FAIL ||
1182			    !scsi_eh_tur(bdr_scmd)) {
1183				list_for_each_entry_safe(scmd, next,
1184							 work_q, eh_entry) {
1185					if (scmd->device == sdev)
 
1186						scsi_eh_finish_cmd(scmd,
1187								   done_q);
1188				}
1189			}
1190		} else {
1191			SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BDR"
1192							  " failed sdev:"
1193							  "0x%p\n",
1194							  current->comm,
1195							   sdev));
1196		}
1197	}
1198
1199	return list_empty(work_q);
1200}
1201
1202/**
1203 * scsi_eh_target_reset - send target reset if needed
1204 * @shost:	scsi host being recovered.
1205 * @work_q:     &list_head for pending commands.
1206 * @done_q:	&list_head for processed commands.
1207 *
1208 * Notes:
1209 *    Try a target reset.
1210 */
1211static int scsi_eh_target_reset(struct Scsi_Host *shost,
1212				struct list_head *work_q,
1213				struct list_head *done_q)
1214{
1215	LIST_HEAD(tmp_list);
1216	LIST_HEAD(check_list);
1217
1218	list_splice_init(work_q, &tmp_list);
1219
1220	while (!list_empty(&tmp_list)) {
1221		struct scsi_cmnd *next, *scmd;
1222		int rtn;
1223		unsigned int id;
1224
 
 
 
 
 
 
 
 
 
 
 
1225		scmd = list_entry(tmp_list.next, struct scsi_cmnd, eh_entry);
1226		id = scmd_id(scmd);
1227
1228		SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending target reset "
1229						  "to target %d\n",
1230						  current->comm, id));
1231		rtn = scsi_try_target_reset(scmd);
1232		if (rtn != SUCCESS && rtn != FAST_IO_FAIL)
1233			SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Target reset"
1234							  " failed target: "
1235							  "%d\n",
1236							  current->comm, id));
1237		list_for_each_entry_safe(scmd, next, &tmp_list, eh_entry) {
1238			if (scmd_id(scmd) != id)
1239				continue;
1240
1241			if (rtn == SUCCESS)
1242				list_move_tail(&scmd->eh_entry, &check_list);
1243			else if (rtn == FAST_IO_FAIL)
1244				scsi_eh_finish_cmd(scmd, done_q);
1245			else
1246				/* push back on work queue for further processing */
1247				list_move(&scmd->eh_entry, work_q);
1248		}
1249	}
1250
1251	return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1252}
1253
1254/**
1255 * scsi_eh_bus_reset - send a bus reset
1256 * @shost:	&scsi host being recovered.
1257 * @work_q:     &list_head for pending commands.
1258 * @done_q:	&list_head for processed commands.
1259 */
1260static int scsi_eh_bus_reset(struct Scsi_Host *shost,
1261			     struct list_head *work_q,
1262			     struct list_head *done_q)
1263{
1264	struct scsi_cmnd *scmd, *chan_scmd, *next;
1265	LIST_HEAD(check_list);
1266	unsigned int channel;
1267	int rtn;
1268
1269	/*
1270	 * we really want to loop over the various channels, and do this on
1271	 * a channel by channel basis.  we should also check to see if any
1272	 * of the failed commands are on soft_reset devices, and if so, skip
1273	 * the reset.
1274	 */
1275
1276	for (channel = 0; channel <= shost->max_channel; channel++) {
 
 
 
 
 
 
 
 
 
1277		chan_scmd = NULL;
1278		list_for_each_entry(scmd, work_q, eh_entry) {
1279			if (channel == scmd_channel(scmd)) {
1280				chan_scmd = scmd;
1281				break;
1282				/*
1283				 * FIXME add back in some support for
1284				 * soft_reset devices.
1285				 */
1286			}
1287		}
1288
1289		if (!chan_scmd)
1290			continue;
1291		SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BRST chan:"
1292						  " %d\n", current->comm,
1293						  channel));
1294		rtn = scsi_try_bus_reset(chan_scmd);
1295		if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1296			list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1297				if (channel == scmd_channel(scmd)) {
1298					if (rtn == FAST_IO_FAIL)
1299						scsi_eh_finish_cmd(scmd,
1300								   done_q);
1301					else
1302						list_move_tail(&scmd->eh_entry,
1303							       &check_list);
1304				}
1305			}
1306		} else {
1307			SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BRST"
1308							  " failed chan: %d\n",
1309							  current->comm,
1310							  channel));
1311		}
1312	}
1313	return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1314}
1315
1316/**
1317 * scsi_eh_host_reset - send a host reset
1318 * @work_q:	list_head for processed commands.
1319 * @done_q:	list_head for processed commands.
1320 */
1321static int scsi_eh_host_reset(struct list_head *work_q,
1322			      struct list_head *done_q)
1323{
1324	struct scsi_cmnd *scmd, *next;
1325	LIST_HEAD(check_list);
1326	int rtn;
1327
1328	if (!list_empty(work_q)) {
1329		scmd = list_entry(work_q->next,
1330				  struct scsi_cmnd, eh_entry);
1331
1332		SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending HRST\n"
1333						  , current->comm));
1334
1335		rtn = scsi_try_host_reset(scmd);
1336		if (rtn == SUCCESS) {
1337			list_splice_init(work_q, &check_list);
1338		} else if (rtn == FAST_IO_FAIL) {
1339			list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1340					scsi_eh_finish_cmd(scmd, done_q);
1341			}
1342		} else {
1343			SCSI_LOG_ERROR_RECOVERY(3, printk("%s: HRST"
1344							  " failed\n",
1345							  current->comm));
1346		}
1347	}
1348	return scsi_eh_test_devices(&check_list, work_q, done_q, 1);
1349}
1350
1351/**
1352 * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
1353 * @work_q:	list_head for processed commands.
1354 * @done_q:	list_head for processed commands.
1355 */
1356static void scsi_eh_offline_sdevs(struct list_head *work_q,
1357				  struct list_head *done_q)
1358{
1359	struct scsi_cmnd *scmd, *next;
1360
1361	list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1362		sdev_printk(KERN_INFO, scmd->device, "Device offlined - "
1363			    "not ready after error recovery\n");
1364		scsi_device_set_state(scmd->device, SDEV_OFFLINE);
1365		if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD) {
1366			/*
1367			 * FIXME: Handle lost cmds.
1368			 */
1369		}
1370		scsi_eh_finish_cmd(scmd, done_q);
1371	}
1372	return;
1373}
1374
1375/**
1376 * scsi_noretry_cmd - determinte if command should be failed fast
1377 * @scmd:	SCSI cmd to examine.
1378 */
1379int scsi_noretry_cmd(struct scsi_cmnd *scmd)
1380{
1381	switch (host_byte(scmd->result)) {
1382	case DID_OK:
1383		break;
 
 
1384	case DID_BUS_BUSY:
1385		return (scmd->request->cmd_flags & REQ_FAILFAST_TRANSPORT);
1386	case DID_PARITY:
1387		return (scmd->request->cmd_flags & REQ_FAILFAST_DEV);
1388	case DID_ERROR:
1389		if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1390		    status_byte(scmd->result) == RESERVATION_CONFLICT)
1391			return 0;
1392		/* fall through */
1393	case DID_SOFT_ERROR:
1394		return (scmd->request->cmd_flags & REQ_FAILFAST_DRIVER);
1395	}
1396
1397	switch (status_byte(scmd->result)) {
1398	case CHECK_CONDITION:
1399		/*
1400		 * assume caller has checked sense and determinted
1401		 * the check condition was retryable.
1402		 */
1403		if (scmd->request->cmd_flags & REQ_FAILFAST_DEV ||
1404		    scmd->request->cmd_type == REQ_TYPE_BLOCK_PC)
1405			return 1;
1406	}
1407
1408	return 0;
 
 
 
 
 
 
 
 
 
1409}
1410
1411/**
1412 * scsi_decide_disposition - Disposition a cmd on return from LLD.
1413 * @scmd:	SCSI cmd to examine.
1414 *
1415 * Notes:
1416 *    This is *only* called when we are examining the status after sending
1417 *    out the actual data command.  any commands that are queued for error
1418 *    recovery (e.g. test_unit_ready) do *not* come through here.
1419 *
1420 *    When this routine returns failed, it means the error handler thread
1421 *    is woken.  In cases where the error code indicates an error that
1422 *    doesn't require the error handler read (i.e. we don't need to
1423 *    abort/reset), this function should return SUCCESS.
1424 */
1425int scsi_decide_disposition(struct scsi_cmnd *scmd)
1426{
1427	int rtn;
1428
1429	/*
1430	 * if the device is offline, then we clearly just pass the result back
1431	 * up to the top level.
1432	 */
1433	if (!scsi_device_online(scmd->device)) {
1434		SCSI_LOG_ERROR_RECOVERY(5, printk("%s: device offline - report"
1435						  " as SUCCESS\n",
1436						  __func__));
1437		return SUCCESS;
1438	}
1439
1440	/*
1441	 * first check the host byte, to see if there is anything in there
1442	 * that would indicate what we need to do.
1443	 */
1444	switch (host_byte(scmd->result)) {
1445	case DID_PASSTHROUGH:
1446		/*
1447		 * no matter what, pass this through to the upper layer.
1448		 * nuke this special code so that it looks like we are saying
1449		 * did_ok.
1450		 */
1451		scmd->result &= 0xff00ffff;
1452		return SUCCESS;
1453	case DID_OK:
1454		/*
1455		 * looks good.  drop through, and check the next byte.
1456		 */
1457		break;
 
 
 
 
 
1458	case DID_NO_CONNECT:
1459	case DID_BAD_TARGET:
1460	case DID_ABORT:
1461		/*
1462		 * note - this means that we just report the status back
1463		 * to the top level driver, not that we actually think
1464		 * that it indicates SUCCESS.
1465		 */
1466		return SUCCESS;
1467		/*
1468		 * when the low level driver returns did_soft_error,
1469		 * it is responsible for keeping an internal retry counter
1470		 * in order to avoid endless loops (db)
1471		 *
1472		 * actually this is a bug in this function here.  we should
1473		 * be mindful of the maximum number of retries specified
1474		 * and not get stuck in a loop.
1475		 */
1476	case DID_SOFT_ERROR:
1477		goto maybe_retry;
1478	case DID_IMM_RETRY:
1479		return NEEDS_RETRY;
1480
1481	case DID_REQUEUE:
1482		return ADD_TO_MLQUEUE;
1483	case DID_TRANSPORT_DISRUPTED:
1484		/*
1485		 * LLD/transport was disrupted during processing of the IO.
1486		 * The transport class is now blocked/blocking,
1487		 * and the transport will decide what to do with the IO
1488		 * based on its timers and recovery capablilities if
1489		 * there are enough retries.
1490		 */
1491		goto maybe_retry;
1492	case DID_TRANSPORT_FAILFAST:
1493		/*
1494		 * The transport decided to failfast the IO (most likely
1495		 * the fast io fail tmo fired), so send IO directly upwards.
1496		 */
1497		return SUCCESS;
1498	case DID_ERROR:
1499		if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
1500		    status_byte(scmd->result) == RESERVATION_CONFLICT)
1501			/*
1502			 * execute reservation conflict processing code
1503			 * lower down
1504			 */
1505			break;
1506		/* fallthrough */
1507	case DID_BUS_BUSY:
1508	case DID_PARITY:
1509		goto maybe_retry;
1510	case DID_TIME_OUT:
1511		/*
1512		 * when we scan the bus, we get timeout messages for
1513		 * these commands if there is no device available.
1514		 * other hosts report did_no_connect for the same thing.
1515		 */
1516		if ((scmd->cmnd[0] == TEST_UNIT_READY ||
1517		     scmd->cmnd[0] == INQUIRY)) {
1518			return SUCCESS;
1519		} else {
1520			return FAILED;
1521		}
1522	case DID_RESET:
1523		return SUCCESS;
1524	default:
1525		return FAILED;
1526	}
1527
1528	/*
1529	 * next, check the message byte.
1530	 */
1531	if (msg_byte(scmd->result) != COMMAND_COMPLETE)
1532		return FAILED;
1533
1534	/*
1535	 * check the status byte to see if this indicates anything special.
1536	 */
1537	switch (status_byte(scmd->result)) {
1538	case QUEUE_FULL:
1539		scsi_handle_queue_full(scmd->device);
1540		/*
1541		 * the case of trying to send too many commands to a
1542		 * tagged queueing device.
1543		 */
1544	case BUSY:
1545		/*
1546		 * device can't talk to us at the moment.  Should only
1547		 * occur (SAM-3) when the task queue is empty, so will cause
1548		 * the empty queue handling to trigger a stall in the
1549		 * device.
1550		 */
1551		return ADD_TO_MLQUEUE;
1552	case GOOD:
 
 
1553		scsi_handle_queue_ramp_up(scmd->device);
1554	case COMMAND_TERMINATED:
1555		return SUCCESS;
1556	case TASK_ABORTED:
1557		goto maybe_retry;
1558	case CHECK_CONDITION:
1559		rtn = scsi_check_sense(scmd);
1560		if (rtn == NEEDS_RETRY)
1561			goto maybe_retry;
1562		else if (rtn == TARGET_ERROR) {
1563			/*
1564			 * Need to modify host byte to signal a
1565			 * permanent target failure
1566			 */
1567			set_host_byte(scmd, DID_TARGET_FAILURE);
1568			rtn = SUCCESS;
1569		}
1570		/* if rtn == FAILED, we have no sense information;
1571		 * returning FAILED will wake the error handler thread
1572		 * to collect the sense and redo the decide
1573		 * disposition */
1574		return rtn;
1575	case CONDITION_GOOD:
1576	case INTERMEDIATE_GOOD:
1577	case INTERMEDIATE_C_GOOD:
1578	case ACA_ACTIVE:
1579		/*
1580		 * who knows?  FIXME(eric)
1581		 */
1582		return SUCCESS;
1583
1584	case RESERVATION_CONFLICT:
1585		sdev_printk(KERN_INFO, scmd->device,
1586			    "reservation conflict\n");
1587		set_host_byte(scmd, DID_NEXUS_FAILURE);
1588		return SUCCESS; /* causes immediate i/o error */
1589	default:
1590		return FAILED;
1591	}
1592	return FAILED;
1593
1594      maybe_retry:
1595
1596	/* we requeue for retry because the error was retryable, and
1597	 * the request was not marked fast fail.  Note that above,
1598	 * even if the request is marked fast fail, we still requeue
1599	 * for queue congestion conditions (QUEUE_FULL or BUSY) */
1600	if ((++scmd->retries) <= scmd->allowed
1601	    && !scsi_noretry_cmd(scmd)) {
1602		return NEEDS_RETRY;
1603	} else {
1604		/*
1605		 * no more retries - report this one back to upper level.
1606		 */
1607		return SUCCESS;
1608	}
1609}
1610
1611static void eh_lock_door_done(struct request *req, int uptodate)
1612{
1613	__blk_put_request(req->q, req);
1614}
1615
1616/**
1617 * scsi_eh_lock_door - Prevent medium removal for the specified device
1618 * @sdev:	SCSI device to prevent medium removal
1619 *
1620 * Locking:
1621 * 	We must be called from process context.
1622 *
1623 * Notes:
1624 * 	We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
1625 * 	head of the devices request queue, and continue.
1626 */
1627static void scsi_eh_lock_door(struct scsi_device *sdev)
1628{
1629	struct request *req;
1630
1631	/*
1632	 * blk_get_request with GFP_KERNEL (__GFP_WAIT) sleeps until a
1633	 * request becomes available
1634	 */
1635	req = blk_get_request(sdev->request_queue, READ, GFP_KERNEL);
1636
1637	req->cmd[0] = ALLOW_MEDIUM_REMOVAL;
1638	req->cmd[1] = 0;
1639	req->cmd[2] = 0;
1640	req->cmd[3] = 0;
1641	req->cmd[4] = SCSI_REMOVAL_PREVENT;
1642	req->cmd[5] = 0;
1643
1644	req->cmd_len = COMMAND_SIZE(req->cmd[0]);
1645
1646	req->cmd_type = REQ_TYPE_BLOCK_PC;
1647	req->cmd_flags |= REQ_QUIET;
1648	req->timeout = 10 * HZ;
1649	req->retries = 5;
1650
1651	blk_execute_rq_nowait(req->q, NULL, req, 1, eh_lock_door_done);
1652}
1653
1654/**
1655 * scsi_restart_operations - restart io operations to the specified host.
1656 * @shost:	Host we are restarting.
1657 *
1658 * Notes:
1659 *    When we entered the error handler, we blocked all further i/o to
1660 *    this device.  we need to 'reverse' this process.
1661 */
1662static void scsi_restart_operations(struct Scsi_Host *shost)
1663{
1664	struct scsi_device *sdev;
1665	unsigned long flags;
1666
1667	/*
1668	 * If the door was locked, we need to insert a door lock request
1669	 * onto the head of the SCSI request queue for the device.  There
1670	 * is no point trying to lock the door of an off-line device.
1671	 */
1672	shost_for_each_device(sdev, shost) {
1673		if (scsi_device_online(sdev) && sdev->locked)
1674			scsi_eh_lock_door(sdev);
1675	}
1676
1677	/*
1678	 * next free up anything directly waiting upon the host.  this
1679	 * will be requests for character device operations, and also for
1680	 * ioctls to queued block devices.
1681	 */
1682	SCSI_LOG_ERROR_RECOVERY(3, printk("%s: waking up host to restart\n",
1683					  __func__));
 
1684
1685	spin_lock_irqsave(shost->host_lock, flags);
1686	if (scsi_host_set_state(shost, SHOST_RUNNING))
1687		if (scsi_host_set_state(shost, SHOST_CANCEL))
1688			BUG_ON(scsi_host_set_state(shost, SHOST_DEL));
1689	spin_unlock_irqrestore(shost->host_lock, flags);
1690
1691	wake_up(&shost->host_wait);
1692
1693	/*
1694	 * finally we need to re-initiate requests that may be pending.  we will
1695	 * have had everything blocked while error handling is taking place, and
1696	 * now that error recovery is done, we will need to ensure that these
1697	 * requests are started.
1698	 */
1699	scsi_run_host_queues(shost);
1700
1701	/*
1702	 * if eh is active and host_eh_scheduled is pending we need to re-run
1703	 * recovery.  we do this check after scsi_run_host_queues() to allow
1704	 * everything pent up since the last eh run a chance to make forward
1705	 * progress before we sync again.  Either we'll immediately re-run
1706	 * recovery or scsi_device_unbusy() will wake us again when these
1707	 * pending commands complete.
1708	 */
1709	spin_lock_irqsave(shost->host_lock, flags);
1710	if (shost->host_eh_scheduled)
1711		if (scsi_host_set_state(shost, SHOST_RECOVERY))
1712			WARN_ON(scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY));
1713	spin_unlock_irqrestore(shost->host_lock, flags);
1714}
1715
1716/**
1717 * scsi_eh_ready_devs - check device ready state and recover if not.
1718 * @shost: 	host to be recovered.
1719 * @work_q:     &list_head for pending commands.
1720 * @done_q:	&list_head for processed commands.
1721 */
1722void scsi_eh_ready_devs(struct Scsi_Host *shost,
1723			struct list_head *work_q,
1724			struct list_head *done_q)
1725{
1726	if (!scsi_eh_stu(shost, work_q, done_q))
1727		if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
1728			if (!scsi_eh_target_reset(shost, work_q, done_q))
1729				if (!scsi_eh_bus_reset(shost, work_q, done_q))
1730					if (!scsi_eh_host_reset(work_q, done_q))
1731						scsi_eh_offline_sdevs(work_q,
1732								      done_q);
1733}
1734EXPORT_SYMBOL_GPL(scsi_eh_ready_devs);
1735
1736/**
1737 * scsi_eh_flush_done_q - finish processed commands or retry them.
1738 * @done_q:	list_head of processed commands.
1739 */
1740void scsi_eh_flush_done_q(struct list_head *done_q)
1741{
1742	struct scsi_cmnd *scmd, *next;
1743
1744	list_for_each_entry_safe(scmd, next, done_q, eh_entry) {
1745		list_del_init(&scmd->eh_entry);
1746		if (scsi_device_online(scmd->device) &&
1747		    !scsi_noretry_cmd(scmd) &&
1748		    (++scmd->retries <= scmd->allowed)) {
1749			SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush"
1750							  " retry cmd: %p\n",
1751							  current->comm,
1752							  scmd));
1753				scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
1754		} else {
1755			/*
1756			 * If just we got sense for the device (called
1757			 * scsi_eh_get_sense), scmd->result is already
1758			 * set, do not set DRIVER_TIMEOUT.
1759			 */
1760			if (!scmd->result)
1761				scmd->result |= (DRIVER_TIMEOUT << 24);
1762			SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush finish"
1763							" cmd: %p\n",
1764							current->comm, scmd));
1765			scsi_finish_command(scmd);
1766		}
1767	}
1768}
1769EXPORT_SYMBOL(scsi_eh_flush_done_q);
1770
1771/**
1772 * scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
1773 * @shost:	Host to unjam.
1774 *
1775 * Notes:
1776 *    When we come in here, we *know* that all commands on the bus have
1777 *    either completed, failed or timed out.  we also know that no further
1778 *    commands are being sent to the host, so things are relatively quiet
1779 *    and we have freedom to fiddle with things as we wish.
1780 *
1781 *    This is only the *default* implementation.  it is possible for
1782 *    individual drivers to supply their own version of this function, and
1783 *    if the maintainer wishes to do this, it is strongly suggested that
1784 *    this function be taken as a template and modified.  this function
1785 *    was designed to correctly handle problems for about 95% of the
1786 *    different cases out there, and it should always provide at least a
1787 *    reasonable amount of error recovery.
1788 *
1789 *    Any command marked 'failed' or 'timeout' must eventually have
1790 *    scsi_finish_cmd() called for it.  we do all of the retry stuff
1791 *    here, so when we restart the host after we return it should have an
1792 *    empty queue.
1793 */
1794static void scsi_unjam_host(struct Scsi_Host *shost)
1795{
1796	unsigned long flags;
1797	LIST_HEAD(eh_work_q);
1798	LIST_HEAD(eh_done_q);
1799
1800	spin_lock_irqsave(shost->host_lock, flags);
1801	list_splice_init(&shost->eh_cmd_q, &eh_work_q);
1802	spin_unlock_irqrestore(shost->host_lock, flags);
1803
1804	SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
1805
1806	if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
1807		if (!scsi_eh_abort_cmds(&eh_work_q, &eh_done_q))
1808			scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
1809
 
 
 
 
1810	scsi_eh_flush_done_q(&eh_done_q);
1811}
1812
1813/**
1814 * scsi_error_handler - SCSI error handler thread
1815 * @data:	Host for which we are running.
1816 *
1817 * Notes:
1818 *    This is the main error handling loop.  This is run as a kernel thread
1819 *    for every SCSI host and handles all error handling activity.
1820 */
1821int scsi_error_handler(void *data)
1822{
1823	struct Scsi_Host *shost = data;
1824
1825	/*
1826	 * We use TASK_INTERRUPTIBLE so that the thread is not
1827	 * counted against the load average as a running process.
1828	 * We never actually get interrupted because kthread_run
1829	 * disables signal delivery for the created thread.
1830	 */
1831	set_current_state(TASK_INTERRUPTIBLE);
1832	while (!kthread_should_stop()) {
 
1833		if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||
1834		    shost->host_failed != shost->host_busy) {
1835			SCSI_LOG_ERROR_RECOVERY(1,
1836				printk("Error handler scsi_eh_%d sleeping\n",
1837					shost->host_no));
1838			schedule();
1839			set_current_state(TASK_INTERRUPTIBLE);
1840			continue;
1841		}
1842
1843		__set_current_state(TASK_RUNNING);
1844		SCSI_LOG_ERROR_RECOVERY(1,
1845			printk("Error handler scsi_eh_%d waking up\n",
1846				shost->host_no));
 
1847
1848		/*
1849		 * We have a host that is failing for some reason.  Figure out
1850		 * what we need to do to get it up and online again (if we can).
1851		 * If we fail, we end up taking the thing offline.
1852		 */
1853		if (!shost->eh_noresume && scsi_autopm_get_host(shost) != 0) {
1854			SCSI_LOG_ERROR_RECOVERY(1,
1855				printk(KERN_ERR "Error handler scsi_eh_%d "
1856						"unable to autoresume\n",
1857						shost->host_no));
1858			continue;
1859		}
1860
1861		if (shost->transportt->eh_strategy_handler)
1862			shost->transportt->eh_strategy_handler(shost);
1863		else
1864			scsi_unjam_host(shost);
1865
1866		/*
1867		 * Note - if the above fails completely, the action is to take
1868		 * individual devices offline and flush the queue of any
1869		 * outstanding requests that may have been pending.  When we
1870		 * restart, we restart any I/O to any other devices on the bus
1871		 * which are still online.
1872		 */
1873		scsi_restart_operations(shost);
1874		if (!shost->eh_noresume)
1875			scsi_autopm_put_host(shost);
1876		set_current_state(TASK_INTERRUPTIBLE);
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);