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v5.9
   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Copyright (C) 1999 Eric Youngdale
   4 * Copyright (C) 2014 Christoph Hellwig
   5 *
   6 *  SCSI queueing library.
   7 *      Initial versions: Eric Youngdale (eric@andante.org).
   8 *                        Based upon conversations with large numbers
   9 *                        of people at Linux Expo.
  10 */
  11
  12#include <linux/bio.h>
  13#include <linux/bitops.h>
  14#include <linux/blkdev.h>
  15#include <linux/completion.h>
  16#include <linux/kernel.h>
  17#include <linux/export.h>
 
 
  18#include <linux/init.h>
  19#include <linux/pci.h>
  20#include <linux/delay.h>
  21#include <linux/hardirq.h>
  22#include <linux/scatterlist.h>
  23#include <linux/blk-mq.h>
  24#include <linux/ratelimit.h>
  25#include <asm/unaligned.h>
  26
  27#include <scsi/scsi.h>
  28#include <scsi/scsi_cmnd.h>
  29#include <scsi/scsi_dbg.h>
  30#include <scsi/scsi_device.h>
  31#include <scsi/scsi_driver.h>
  32#include <scsi/scsi_eh.h>
  33#include <scsi/scsi_host.h>
  34#include <scsi/scsi_transport.h> /* __scsi_init_queue() */
  35#include <scsi/scsi_dh.h>
  36
  37#include <trace/events/scsi.h>
  38
  39#include "scsi_debugfs.h"
  40#include "scsi_priv.h"
  41#include "scsi_logging.h"
  42
  43/*
  44 * Size of integrity metadata is usually small, 1 inline sg should
  45 * cover normal cases.
  46 */
  47#ifdef CONFIG_ARCH_NO_SG_CHAIN
  48#define  SCSI_INLINE_PROT_SG_CNT  0
  49#define  SCSI_INLINE_SG_CNT  0
  50#else
  51#define  SCSI_INLINE_PROT_SG_CNT  1
  52#define  SCSI_INLINE_SG_CNT  2
  53#endif
  54
  55static struct kmem_cache *scsi_sense_cache;
  56static struct kmem_cache *scsi_sense_isadma_cache;
  57static DEFINE_MUTEX(scsi_sense_cache_mutex);
  58
  59static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd);
  60
  61static inline struct kmem_cache *
  62scsi_select_sense_cache(bool unchecked_isa_dma)
  63{
  64	return unchecked_isa_dma ? scsi_sense_isadma_cache : scsi_sense_cache;
  65}
  66
  67static void scsi_free_sense_buffer(bool unchecked_isa_dma,
  68				   unsigned char *sense_buffer)
  69{
  70	kmem_cache_free(scsi_select_sense_cache(unchecked_isa_dma),
  71			sense_buffer);
  72}
  73
  74static unsigned char *scsi_alloc_sense_buffer(bool unchecked_isa_dma,
  75	gfp_t gfp_mask, int numa_node)
  76{
  77	return kmem_cache_alloc_node(scsi_select_sense_cache(unchecked_isa_dma),
  78				     gfp_mask, numa_node);
  79}
  80
  81int scsi_init_sense_cache(struct Scsi_Host *shost)
  82{
  83	struct kmem_cache *cache;
  84	int ret = 0;
 
 
  85
  86	mutex_lock(&scsi_sense_cache_mutex);
  87	cache = scsi_select_sense_cache(shost->unchecked_isa_dma);
  88	if (cache)
  89		goto exit;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  90
  91	if (shost->unchecked_isa_dma) {
  92		scsi_sense_isadma_cache =
  93			kmem_cache_create("scsi_sense_cache(DMA)",
  94				SCSI_SENSE_BUFFERSIZE, 0,
  95				SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA, NULL);
  96		if (!scsi_sense_isadma_cache)
  97			ret = -ENOMEM;
  98	} else {
  99		scsi_sense_cache =
 100			kmem_cache_create_usercopy("scsi_sense_cache",
 101				SCSI_SENSE_BUFFERSIZE, 0, SLAB_HWCACHE_ALIGN,
 102				0, SCSI_SENSE_BUFFERSIZE, NULL);
 103		if (!scsi_sense_cache)
 104			ret = -ENOMEM;
 105	}
 106 exit:
 107	mutex_unlock(&scsi_sense_cache_mutex);
 108	return ret;
 109}
 110
 111/*
 112 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
 113 * not change behaviour from the previous unplug mechanism, experimentation
 114 * may prove this needs changing.
 115 */
 116#define SCSI_QUEUE_DELAY	3
 117
 118static void
 119scsi_set_blocked(struct scsi_cmnd *cmd, int reason)
 120{
 121	struct Scsi_Host *host = cmd->device->host;
 122	struct scsi_device *device = cmd->device;
 123	struct scsi_target *starget = scsi_target(device);
 124
 125	/*
 126	 * Set the appropriate busy bit for the device/host.
 127	 *
 128	 * If the host/device isn't busy, assume that something actually
 129	 * completed, and that we should be able to queue a command now.
 130	 *
 131	 * Note that the prior mid-layer assumption that any host could
 132	 * always queue at least one command is now broken.  The mid-layer
 133	 * will implement a user specifiable stall (see
 134	 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
 135	 * if a command is requeued with no other commands outstanding
 136	 * either for the device or for the host.
 137	 */
 138	switch (reason) {
 139	case SCSI_MLQUEUE_HOST_BUSY:
 140		atomic_set(&host->host_blocked, host->max_host_blocked);
 141		break;
 142	case SCSI_MLQUEUE_DEVICE_BUSY:
 143	case SCSI_MLQUEUE_EH_RETRY:
 144		atomic_set(&device->device_blocked,
 145			   device->max_device_blocked);
 146		break;
 147	case SCSI_MLQUEUE_TARGET_BUSY:
 148		atomic_set(&starget->target_blocked,
 149			   starget->max_target_blocked);
 150		break;
 151	}
 152}
 153
 154static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd)
 155{
 156	if (cmd->request->rq_flags & RQF_DONTPREP) {
 157		cmd->request->rq_flags &= ~RQF_DONTPREP;
 158		scsi_mq_uninit_cmd(cmd);
 159	} else {
 160		WARN_ON_ONCE(true);
 161	}
 162	blk_mq_requeue_request(cmd->request, true);
 163}
 164
 165/**
 166 * __scsi_queue_insert - private queue insertion
 167 * @cmd: The SCSI command being requeued
 168 * @reason:  The reason for the requeue
 169 * @unbusy: Whether the queue should be unbusied
 170 *
 171 * This is a private queue insertion.  The public interface
 172 * scsi_queue_insert() always assumes the queue should be unbusied
 173 * because it's always called before the completion.  This function is
 174 * for a requeue after completion, which should only occur in this
 175 * file.
 176 */
 177static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy)
 178{
 179	struct scsi_device *device = cmd->device;
 
 
 180
 181	SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd,
 182		"Inserting command %p into mlqueue\n", cmd));
 183
 184	scsi_set_blocked(cmd, reason);
 185
 186	/*
 187	 * Decrement the counters, since these commands are no longer
 188	 * active on the host/device.
 189	 */
 190	if (unbusy)
 191		scsi_device_unbusy(device, cmd);
 192
 193	/*
 194	 * Requeue this command.  It will go before all other commands
 195	 * that are already in the queue. Schedule requeue work under
 196	 * lock such that the kblockd_schedule_work() call happens
 197	 * before blk_cleanup_queue() finishes.
 198	 */
 199	cmd->result = 0;
 200
 201	blk_mq_requeue_request(cmd->request, true);
 
 
 
 
 
 
 202}
 203
 204/**
 205 * scsi_queue_insert - Reinsert a command in the queue.
 206 * @cmd:    command that we are adding to queue.
 207 * @reason: why we are inserting command to queue.
 
 
 
 208 *
 209 * We do this for one of two cases. Either the host is busy and it cannot accept
 210 * any more commands for the time being, or the device returned QUEUE_FULL and
 211 * can accept no more commands.
 212 *
 213 * Context: This could be called either from an interrupt context or a normal
 214 * process context.
 
 
 
 
 
 
 215 */
 216void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
 217{
 218	__scsi_queue_insert(cmd, reason, true);
 219}
 220
 221
 222/**
 223 * __scsi_execute - insert request and wait for the result
 224 * @sdev:	scsi device
 225 * @cmd:	scsi command
 226 * @data_direction: data direction
 227 * @buffer:	data buffer
 228 * @bufflen:	len of buffer
 229 * @sense:	optional sense buffer
 230 * @sshdr:	optional decoded sense header
 231 * @timeout:	request timeout in seconds
 232 * @retries:	number of times to retry request
 233 * @flags:	flags for ->cmd_flags
 234 * @rq_flags:	flags for ->rq_flags
 235 * @resid:	optional residual length
 236 *
 237 * Returns the scsi_cmnd result field if a command was executed, or a negative
 238 * Linux error code if we didn't get that far.
 239 */
 240int __scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
 241		 int data_direction, void *buffer, unsigned bufflen,
 242		 unsigned char *sense, struct scsi_sense_hdr *sshdr,
 243		 int timeout, int retries, u64 flags, req_flags_t rq_flags,
 244		 int *resid)
 245{
 246	struct request *req;
 247	struct scsi_request *rq;
 248	int ret = DRIVER_ERROR << 24;
 249
 250	req = blk_get_request(sdev->request_queue,
 251			data_direction == DMA_TO_DEVICE ?
 252			REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, BLK_MQ_REQ_PREEMPT);
 253	if (IS_ERR(req))
 254		return ret;
 255	rq = scsi_req(req);
 256
 257	if (bufflen &&	blk_rq_map_kern(sdev->request_queue, req,
 258					buffer, bufflen, GFP_NOIO))
 259		goto out;
 260
 261	rq->cmd_len = COMMAND_SIZE(cmd[0]);
 262	memcpy(rq->cmd, cmd, rq->cmd_len);
 263	rq->retries = retries;
 
 
 264	req->timeout = timeout;
 265	req->cmd_flags |= flags;
 266	req->rq_flags |= rq_flags | RQF_QUIET;
 267
 268	/*
 269	 * head injection *required* here otherwise quiesce won't work
 270	 */
 271	blk_execute_rq(req->q, NULL, req, 1);
 272
 273	/*
 274	 * Some devices (USB mass-storage in particular) may transfer
 275	 * garbage data together with a residue indicating that the data
 276	 * is invalid.  Prevent the garbage from being misinterpreted
 277	 * and prevent security leaks by zeroing out the excess data.
 278	 */
 279	if (unlikely(rq->resid_len > 0 && rq->resid_len <= bufflen))
 280		memset(buffer + (bufflen - rq->resid_len), 0, rq->resid_len);
 281
 282	if (resid)
 283		*resid = rq->resid_len;
 284	if (sense && rq->sense_len)
 285		memcpy(sense, rq->sense, SCSI_SENSE_BUFFERSIZE);
 286	if (sshdr)
 287		scsi_normalize_sense(rq->sense, rq->sense_len, sshdr);
 288	ret = rq->result;
 289 out:
 290	blk_put_request(req);
 291
 292	return ret;
 293}
 294EXPORT_SYMBOL(__scsi_execute);
 295
 296/**
 297 * scsi_init_cmd_errh - Initialize cmd fields related to error handling.
 298 * @cmd:  command that is ready to be queued.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 299 *
 300 * This function has the job of initializing a number of fields related to error
 301 * handling. Typically this will be called once for each command, as required.
 
 302 */
 303static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
 304{
 
 305	scsi_set_resid(cmd, 0);
 306	memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
 307	if (cmd->cmd_len == 0)
 308		cmd->cmd_len = scsi_command_size(cmd->cmnd);
 309}
 310
 311/*
 312 * Wake up the error handler if necessary. Avoid as follows that the error
 313 * handler is not woken up if host in-flight requests number ==
 314 * shost->host_failed: use call_rcu() in scsi_eh_scmd_add() in combination
 315 * with an RCU read lock in this function to ensure that this function in
 316 * its entirety either finishes before scsi_eh_scmd_add() increases the
 317 * host_failed counter or that it notices the shost state change made by
 318 * scsi_eh_scmd_add().
 319 */
 320static void scsi_dec_host_busy(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
 321{
 322	unsigned long flags;
 323
 324	rcu_read_lock();
 325	__clear_bit(SCMD_STATE_INFLIGHT, &cmd->state);
 326	if (unlikely(scsi_host_in_recovery(shost))) {
 327		spin_lock_irqsave(shost->host_lock, flags);
 328		if (shost->host_failed || shost->host_eh_scheduled)
 329			scsi_eh_wakeup(shost);
 330		spin_unlock_irqrestore(shost->host_lock, flags);
 331	}
 332	rcu_read_unlock();
 333}
 334
 335void scsi_device_unbusy(struct scsi_device *sdev, struct scsi_cmnd *cmd)
 336{
 337	struct Scsi_Host *shost = sdev->host;
 338	struct scsi_target *starget = scsi_target(sdev);
 
 339
 340	scsi_dec_host_busy(shost, cmd);
 341
 342	if (starget->can_queue > 0)
 343		atomic_dec(&starget->target_busy);
 344
 
 
 
 
 
 
 
 345	atomic_dec(&sdev->device_busy);
 346}
 347
 348static void scsi_kick_queue(struct request_queue *q)
 349{
 350	blk_mq_run_hw_queues(q, false);
 
 
 
 351}
 352
 353/*
 354 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
 355 * and call blk_run_queue for all the scsi_devices on the target -
 356 * including current_sdev first.
 357 *
 358 * Called with *no* scsi locks held.
 359 */
 360static void scsi_single_lun_run(struct scsi_device *current_sdev)
 361{
 362	struct Scsi_Host *shost = current_sdev->host;
 363	struct scsi_device *sdev, *tmp;
 364	struct scsi_target *starget = scsi_target(current_sdev);
 365	unsigned long flags;
 366
 367	spin_lock_irqsave(shost->host_lock, flags);
 368	starget->starget_sdev_user = NULL;
 369	spin_unlock_irqrestore(shost->host_lock, flags);
 370
 371	/*
 372	 * Call blk_run_queue for all LUNs on the target, starting with
 373	 * current_sdev. We race with others (to set starget_sdev_user),
 374	 * but in most cases, we will be first. Ideally, each LU on the
 375	 * target would get some limited time or requests on the target.
 376	 */
 377	scsi_kick_queue(current_sdev->request_queue);
 378
 379	spin_lock_irqsave(shost->host_lock, flags);
 380	if (starget->starget_sdev_user)
 381		goto out;
 382	list_for_each_entry_safe(sdev, tmp, &starget->devices,
 383			same_target_siblings) {
 384		if (sdev == current_sdev)
 385			continue;
 386		if (scsi_device_get(sdev))
 387			continue;
 388
 389		spin_unlock_irqrestore(shost->host_lock, flags);
 390		scsi_kick_queue(sdev->request_queue);
 391		spin_lock_irqsave(shost->host_lock, flags);
 392
 393		scsi_device_put(sdev);
 394	}
 395 out:
 396	spin_unlock_irqrestore(shost->host_lock, flags);
 397}
 398
 399static inline bool scsi_device_is_busy(struct scsi_device *sdev)
 400{
 401	if (atomic_read(&sdev->device_busy) >= sdev->queue_depth)
 402		return true;
 403	if (atomic_read(&sdev->device_blocked) > 0)
 404		return true;
 405	return false;
 406}
 407
 408static inline bool scsi_target_is_busy(struct scsi_target *starget)
 409{
 410	if (starget->can_queue > 0) {
 411		if (atomic_read(&starget->target_busy) >= starget->can_queue)
 412			return true;
 413		if (atomic_read(&starget->target_blocked) > 0)
 414			return true;
 415	}
 416	return false;
 417}
 418
 419static inline bool scsi_host_is_busy(struct Scsi_Host *shost)
 420{
 
 
 
 421	if (atomic_read(&shost->host_blocked) > 0)
 422		return true;
 423	if (shost->host_self_blocked)
 424		return true;
 425	return false;
 426}
 427
 428static void scsi_starved_list_run(struct Scsi_Host *shost)
 429{
 430	LIST_HEAD(starved_list);
 431	struct scsi_device *sdev;
 432	unsigned long flags;
 433
 434	spin_lock_irqsave(shost->host_lock, flags);
 435	list_splice_init(&shost->starved_list, &starved_list);
 436
 437	while (!list_empty(&starved_list)) {
 438		struct request_queue *slq;
 439
 440		/*
 441		 * As long as shost is accepting commands and we have
 442		 * starved queues, call blk_run_queue. scsi_request_fn
 443		 * drops the queue_lock and can add us back to the
 444		 * starved_list.
 445		 *
 446		 * host_lock protects the starved_list and starved_entry.
 447		 * scsi_request_fn must get the host_lock before checking
 448		 * or modifying starved_list or starved_entry.
 449		 */
 450		if (scsi_host_is_busy(shost))
 451			break;
 452
 453		sdev = list_entry(starved_list.next,
 454				  struct scsi_device, starved_entry);
 455		list_del_init(&sdev->starved_entry);
 456		if (scsi_target_is_busy(scsi_target(sdev))) {
 457			list_move_tail(&sdev->starved_entry,
 458				       &shost->starved_list);
 459			continue;
 460		}
 461
 462		/*
 463		 * Once we drop the host lock, a racing scsi_remove_device()
 464		 * call may remove the sdev from the starved list and destroy
 465		 * it and the queue.  Mitigate by taking a reference to the
 466		 * queue and never touching the sdev again after we drop the
 467		 * host lock.  Note: if __scsi_remove_device() invokes
 468		 * blk_cleanup_queue() before the queue is run from this
 469		 * function then blk_run_queue() will return immediately since
 470		 * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING.
 471		 */
 472		slq = sdev->request_queue;
 473		if (!blk_get_queue(slq))
 474			continue;
 475		spin_unlock_irqrestore(shost->host_lock, flags);
 476
 477		scsi_kick_queue(slq);
 478		blk_put_queue(slq);
 479
 480		spin_lock_irqsave(shost->host_lock, flags);
 481	}
 482	/* put any unprocessed entries back */
 483	list_splice(&starved_list, &shost->starved_list);
 484	spin_unlock_irqrestore(shost->host_lock, flags);
 485}
 486
 487/**
 488 * scsi_run_queue - Select a proper request queue to serve next.
 489 * @q:  last request's queue
 
 490 *
 491 * The previous command was completely finished, start a new one if possible.
 
 
 
 
 
 492 */
 493static void scsi_run_queue(struct request_queue *q)
 494{
 495	struct scsi_device *sdev = q->queuedata;
 496
 497	if (scsi_target(sdev)->single_lun)
 498		scsi_single_lun_run(sdev);
 499	if (!list_empty(&sdev->host->starved_list))
 500		scsi_starved_list_run(sdev->host);
 501
 502	blk_mq_run_hw_queues(q, false);
 
 
 
 503}
 504
 505void scsi_requeue_run_queue(struct work_struct *work)
 506{
 507	struct scsi_device *sdev;
 508	struct request_queue *q;
 509
 510	sdev = container_of(work, struct scsi_device, requeue_work);
 511	q = sdev->request_queue;
 512	scsi_run_queue(q);
 513}
 514
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 515void scsi_run_host_queues(struct Scsi_Host *shost)
 516{
 517	struct scsi_device *sdev;
 518
 519	shost_for_each_device(sdev, shost)
 520		scsi_run_queue(sdev->request_queue);
 521}
 522
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 523static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
 524{
 525	if (!blk_rq_is_passthrough(cmd->request)) {
 526		struct scsi_driver *drv = scsi_cmd_to_driver(cmd);
 527
 528		if (drv->uninit_command)
 529			drv->uninit_command(cmd);
 530	}
 531}
 532
 533static void scsi_free_sgtables(struct scsi_cmnd *cmd)
 534{
 535	if (cmd->sdb.table.nents)
 536		sg_free_table_chained(&cmd->sdb.table,
 537				SCSI_INLINE_SG_CNT);
 
 538	if (scsi_prot_sg_count(cmd))
 539		sg_free_table_chained(&cmd->prot_sdb->table,
 540				SCSI_INLINE_PROT_SG_CNT);
 541}
 542
 543static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
 544{
 545	scsi_free_sgtables(cmd);
 
 
 
 
 546	scsi_uninit_cmd(cmd);
 
 
 
 
 
 
 
 547}
 548
 549static void scsi_run_queue_async(struct scsi_device *sdev)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 550{
 551	if (scsi_target(sdev)->single_lun ||
 552	    !list_empty(&sdev->host->starved_list))
 553		kblockd_schedule_work(&sdev->requeue_work);
 554	else
 555		blk_mq_run_hw_queues(sdev->request_queue, true);
 
 
 556}
 557
 558/* Returns false when no more bytes to process, true if there are more */
 559static bool scsi_end_request(struct request *req, blk_status_t error,
 560		unsigned int bytes)
 561{
 562	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
 
 
 
 
 
 
 
 
 
 
 563	struct scsi_device *sdev = cmd->device;
 564	struct request_queue *q = sdev->request_queue;
 565
 566	if (blk_update_request(req, error, bytes))
 567		return true;
 568
 
 
 
 
 
 569	if (blk_queue_add_random(q))
 570		add_disk_randomness(req->rq_disk);
 571
 572	if (!blk_rq_is_scsi(req)) {
 573		WARN_ON_ONCE(!(cmd->flags & SCMD_INITIALIZED));
 574		cmd->flags &= ~SCMD_INITIALIZED;
 575	}
 
 
 
 
 
 576
 577	/*
 578	 * Calling rcu_barrier() is not necessary here because the
 579	 * SCSI error handler guarantees that the function called by
 580	 * call_rcu() has been called before scsi_end_request() is
 581	 * called.
 582	 */
 583	destroy_rcu_head(&cmd->rcu);
 584
 585	/*
 586	 * In the MQ case the command gets freed by __blk_mq_end_request,
 587	 * so we have to do all cleanup that depends on it earlier.
 588	 *
 589	 * We also can't kick the queues from irq context, so we
 590	 * will have to defer it to a workqueue.
 591	 */
 592	scsi_mq_uninit_cmd(cmd);
 593
 594	/*
 595	 * queue is still alive, so grab the ref for preventing it
 596	 * from being cleaned up during running queue.
 597	 */
 598	percpu_ref_get(&q->q_usage_counter);
 
 599
 600	__blk_mq_end_request(req, error);
 601
 602	scsi_run_queue_async(sdev);
 
 
 603
 604	percpu_ref_put(&q->q_usage_counter);
 605	return false;
 606}
 607
 608/**
 609 * scsi_result_to_blk_status - translate a SCSI result code into blk_status_t
 610 * @cmd:	SCSI command
 611 * @result:	scsi error code
 612 *
 613 * Translate a SCSI result code into a blk_status_t value. May reset the host
 614 * byte of @cmd->result.
 
 
 
 
 
 
 615 */
 616static blk_status_t scsi_result_to_blk_status(struct scsi_cmnd *cmd, int result)
 617{
 618	switch (host_byte(result)) {
 619	case DID_OK:
 620		/*
 621		 * Also check the other bytes than the status byte in result
 622		 * to handle the case when a SCSI LLD sets result to
 623		 * DRIVER_SENSE << 24 without setting SAM_STAT_CHECK_CONDITION.
 624		 */
 625		if (scsi_status_is_good(result) && (result & ~0xff) == 0)
 626			return BLK_STS_OK;
 627		return BLK_STS_IOERR;
 628	case DID_TRANSPORT_FAILFAST:
 629		return BLK_STS_TRANSPORT;
 
 630	case DID_TARGET_FAILURE:
 631		set_host_byte(cmd, DID_OK);
 632		return BLK_STS_TARGET;
 
 633	case DID_NEXUS_FAILURE:
 634		set_host_byte(cmd, DID_OK);
 635		return BLK_STS_NEXUS;
 
 636	case DID_ALLOC_FAILURE:
 637		set_host_byte(cmd, DID_OK);
 638		return BLK_STS_NOSPC;
 
 639	case DID_MEDIUM_ERROR:
 640		set_host_byte(cmd, DID_OK);
 641		return BLK_STS_MEDIUM;
 
 642	default:
 643		return BLK_STS_IOERR;
 
 644	}
 645}
 646
 647/* Helper for scsi_io_completion() when "reprep" action required. */
 648static void scsi_io_completion_reprep(struct scsi_cmnd *cmd,
 649				      struct request_queue *q)
 650{
 651	/* A new command will be prepared and issued. */
 652	scsi_mq_requeue_cmd(cmd);
 653}
 654
 655/* Helper for scsi_io_completion() when special action required. */
 656static void scsi_io_completion_action(struct scsi_cmnd *cmd, int result)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 657{
 
 658	struct request_queue *q = cmd->device->request_queue;
 659	struct request *req = cmd->request;
 660	int level = 0;
 
 
 
 661	enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,
 662	      ACTION_DELAYED_RETRY} action;
 663	unsigned long wait_for = (cmd->allowed + 1) * req->timeout;
 664	struct scsi_sense_hdr sshdr;
 665	bool sense_valid;
 666	bool sense_current = true;      /* false implies "deferred sense" */
 667	blk_status_t blk_stat;
 668
 669	sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
 670	if (sense_valid)
 671		sense_current = !scsi_sense_is_deferred(&sshdr);
 672
 673	blk_stat = scsi_result_to_blk_status(cmd, result);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 674
 675	if (host_byte(result) == DID_RESET) {
 676		/* Third party bus reset or reset for error recovery
 677		 * reasons.  Just retry the command and see what
 678		 * happens.
 679		 */
 680		action = ACTION_RETRY;
 681	} else if (sense_valid && sense_current) {
 682		switch (sshdr.sense_key) {
 683		case UNIT_ATTENTION:
 684			if (cmd->device->removable) {
 685				/* Detected disc change.  Set a bit
 686				 * and quietly refuse further access.
 687				 */
 688				cmd->device->changed = 1;
 689				action = ACTION_FAIL;
 690			} else {
 691				/* Must have been a power glitch, or a
 692				 * bus reset.  Could not have been a
 693				 * media change, so we just retry the
 694				 * command and see what happens.
 695				 */
 696				action = ACTION_RETRY;
 697			}
 698			break;
 699		case ILLEGAL_REQUEST:
 700			/* If we had an ILLEGAL REQUEST returned, then
 701			 * we may have performed an unsupported
 702			 * command.  The only thing this should be
 703			 * would be a ten byte read where only a six
 704			 * byte read was supported.  Also, on a system
 705			 * where READ CAPACITY failed, we may have
 706			 * read past the end of the disk.
 707			 */
 708			if ((cmd->device->use_10_for_rw &&
 709			    sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
 710			    (cmd->cmnd[0] == READ_10 ||
 711			     cmd->cmnd[0] == WRITE_10)) {
 712				/* This will issue a new 6-byte command. */
 713				cmd->device->use_10_for_rw = 0;
 714				action = ACTION_REPREP;
 715			} else if (sshdr.asc == 0x10) /* DIX */ {
 716				action = ACTION_FAIL;
 717				blk_stat = BLK_STS_PROTECTION;
 718			/* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
 719			} else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
 720				action = ACTION_FAIL;
 721				blk_stat = BLK_STS_TARGET;
 722			} else
 723				action = ACTION_FAIL;
 724			break;
 725		case ABORTED_COMMAND:
 726			action = ACTION_FAIL;
 727			if (sshdr.asc == 0x10) /* DIF */
 728				blk_stat = BLK_STS_PROTECTION;
 729			break;
 730		case NOT_READY:
 731			/* If the device is in the process of becoming
 732			 * ready, or has a temporary blockage, retry.
 733			 */
 734			if (sshdr.asc == 0x04) {
 735				switch (sshdr.ascq) {
 736				case 0x01: /* becoming ready */
 737				case 0x04: /* format in progress */
 738				case 0x05: /* rebuild in progress */
 739				case 0x06: /* recalculation in progress */
 740				case 0x07: /* operation in progress */
 741				case 0x08: /* Long write in progress */
 742				case 0x09: /* self test in progress */
 743				case 0x14: /* space allocation in progress */
 744				case 0x1a: /* start stop unit in progress */
 745				case 0x1b: /* sanitize in progress */
 746				case 0x1d: /* configuration in progress */
 747				case 0x24: /* depopulation in progress */
 748					action = ACTION_DELAYED_RETRY;
 749					break;
 750				default:
 751					action = ACTION_FAIL;
 752					break;
 753				}
 754			} else
 755				action = ACTION_FAIL;
 756			break;
 757		case VOLUME_OVERFLOW:
 758			/* See SSC3rXX or current. */
 759			action = ACTION_FAIL;
 760			break;
 761		default:
 762			action = ACTION_FAIL;
 763			break;
 764		}
 765	} else
 766		action = ACTION_FAIL;
 767
 768	if (action != ACTION_FAIL &&
 769	    time_before(cmd->jiffies_at_alloc + wait_for, jiffies))
 770		action = ACTION_FAIL;
 771
 772	switch (action) {
 773	case ACTION_FAIL:
 774		/* Give up and fail the remainder of the request */
 775		if (!(req->rq_flags & RQF_QUIET)) {
 776			static DEFINE_RATELIMIT_STATE(_rs,
 777					DEFAULT_RATELIMIT_INTERVAL,
 778					DEFAULT_RATELIMIT_BURST);
 779
 780			if (unlikely(scsi_logging_level))
 781				level =
 782				     SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
 783						    SCSI_LOG_MLCOMPLETE_BITS);
 784
 785			/*
 786			 * if logging is enabled the failure will be printed
 787			 * in scsi_log_completion(), so avoid duplicate messages
 788			 */
 789			if (!level && __ratelimit(&_rs)) {
 790				scsi_print_result(cmd, NULL, FAILED);
 791				if (driver_byte(result) == DRIVER_SENSE)
 792					scsi_print_sense(cmd);
 793				scsi_print_command(cmd);
 794			}
 795		}
 796		if (!scsi_end_request(req, blk_stat, blk_rq_err_bytes(req)))
 797			return;
 798		fallthrough;
 799	case ACTION_REPREP:
 800		scsi_io_completion_reprep(cmd, q);
 
 
 
 
 
 
 
 
 
 
 
 801		break;
 802	case ACTION_RETRY:
 803		/* Retry the same command immediately */
 804		__scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, false);
 805		break;
 806	case ACTION_DELAYED_RETRY:
 807		/* Retry the same command after a delay */
 808		__scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, false);
 809		break;
 810	}
 811}
 812
 813/*
 814 * Helper for scsi_io_completion() when cmd->result is non-zero. Returns a
 815 * new result that may suppress further error checking. Also modifies
 816 * *blk_statp in some cases.
 817 */
 818static int scsi_io_completion_nz_result(struct scsi_cmnd *cmd, int result,
 819					blk_status_t *blk_statp)
 820{
 821	bool sense_valid;
 822	bool sense_current = true;	/* false implies "deferred sense" */
 823	struct request *req = cmd->request;
 824	struct scsi_sense_hdr sshdr;
 825
 826	sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
 827	if (sense_valid)
 828		sense_current = !scsi_sense_is_deferred(&sshdr);
 829
 830	if (blk_rq_is_passthrough(req)) {
 831		if (sense_valid) {
 832			/*
 833			 * SG_IO wants current and deferred errors
 834			 */
 835			scsi_req(req)->sense_len =
 836				min(8 + cmd->sense_buffer[7],
 837				    SCSI_SENSE_BUFFERSIZE);
 838		}
 839		if (sense_current)
 840			*blk_statp = scsi_result_to_blk_status(cmd, result);
 841	} else if (blk_rq_bytes(req) == 0 && sense_current) {
 842		/*
 843		 * Flush commands do not transfers any data, and thus cannot use
 844		 * good_bytes != blk_rq_bytes(req) as the signal for an error.
 845		 * This sets *blk_statp explicitly for the problem case.
 846		 */
 847		*blk_statp = scsi_result_to_blk_status(cmd, result);
 848	}
 849	/*
 850	 * Recovered errors need reporting, but they're always treated as
 851	 * success, so fiddle the result code here.  For passthrough requests
 852	 * we already took a copy of the original into sreq->result which
 853	 * is what gets returned to the user
 854	 */
 855	if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
 856		bool do_print = true;
 857		/*
 858		 * if ATA PASS-THROUGH INFORMATION AVAILABLE [0x0, 0x1d]
 859		 * skip print since caller wants ATA registers. Only occurs
 860		 * on SCSI ATA PASS_THROUGH commands when CK_COND=1
 861		 */
 862		if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
 863			do_print = false;
 864		else if (req->rq_flags & RQF_QUIET)
 865			do_print = false;
 866		if (do_print)
 867			scsi_print_sense(cmd);
 868		result = 0;
 869		/* for passthrough, *blk_statp may be set */
 870		*blk_statp = BLK_STS_OK;
 871	}
 872	/*
 873	 * Another corner case: the SCSI status byte is non-zero but 'good'.
 874	 * Example: PRE-FETCH command returns SAM_STAT_CONDITION_MET when
 875	 * it is able to fit nominated LBs in its cache (and SAM_STAT_GOOD
 876	 * if it can't fit). Treat SAM_STAT_CONDITION_MET and the related
 877	 * intermediate statuses (both obsolete in SAM-4) as good.
 878	 */
 879	if (status_byte(result) && scsi_status_is_good(result)) {
 880		result = 0;
 881		*blk_statp = BLK_STS_OK;
 882	}
 883	return result;
 884}
 885
 886/**
 887 * scsi_io_completion - Completion processing for SCSI commands.
 888 * @cmd:	command that is finished.
 889 * @good_bytes:	number of processed bytes.
 890 *
 891 * We will finish off the specified number of sectors. If we are done, the
 892 * command block will be released and the queue function will be goosed. If we
 893 * are not done then we have to figure out what to do next:
 894 *
 895 *   a) We can call scsi_io_completion_reprep().  The request will be
 896 *	unprepared and put back on the queue.  Then a new command will
 897 *	be created for it.  This should be used if we made forward
 898 *	progress, or if we want to switch from READ(10) to READ(6) for
 899 *	example.
 900 *
 901 *   b) We can call scsi_io_completion_action().  The request will be
 902 *	put back on the queue and retried using the same command as
 903 *	before, possibly after a delay.
 904 *
 905 *   c) We can call scsi_end_request() with blk_stat other than
 906 *	BLK_STS_OK, to fail the remainder of the request.
 907 */
 908void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
 909{
 910	int result = cmd->result;
 911	struct request_queue *q = cmd->device->request_queue;
 912	struct request *req = cmd->request;
 913	blk_status_t blk_stat = BLK_STS_OK;
 914
 915	if (unlikely(result))	/* a nz result may or may not be an error */
 916		result = scsi_io_completion_nz_result(cmd, result, &blk_stat);
 917
 918	if (unlikely(blk_rq_is_passthrough(req))) {
 919		/*
 920		 * scsi_result_to_blk_status may have reset the host_byte
 921		 */
 922		scsi_req(req)->result = cmd->result;
 923	}
 924
 925	/*
 926	 * Next deal with any sectors which we were able to correctly
 927	 * handle.
 928	 */
 929	SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd,
 930		"%u sectors total, %d bytes done.\n",
 931		blk_rq_sectors(req), good_bytes));
 932
 933	/*
 934	 * Failed, zero length commands always need to drop down
 935	 * to retry code. Fast path should return in this block.
 936	 */
 937	if (likely(blk_rq_bytes(req) > 0 || blk_stat == BLK_STS_OK)) {
 938		if (likely(!scsi_end_request(req, blk_stat, good_bytes)))
 939			return; /* no bytes remaining */
 940	}
 941
 942	/* Kill remainder if no retries. */
 943	if (unlikely(blk_stat && scsi_noretry_cmd(cmd))) {
 944		if (scsi_end_request(req, blk_stat, blk_rq_bytes(req)))
 945			WARN_ONCE(true,
 946			    "Bytes remaining after failed, no-retry command");
 947		return;
 948	}
 949
 950	/*
 951	 * If there had been no error, but we have leftover bytes in the
 952	 * requeues just queue the command up again.
 953	 */
 954	if (likely(result == 0))
 955		scsi_io_completion_reprep(cmd, q);
 956	else
 957		scsi_io_completion_action(cmd, result);
 
 958}
 959
 960static inline bool scsi_cmd_needs_dma_drain(struct scsi_device *sdev,
 961		struct request *rq)
 962{
 963	return sdev->dma_drain_len && blk_rq_is_passthrough(rq) &&
 964	       !op_is_write(req_op(rq)) &&
 965	       sdev->host->hostt->dma_need_drain(rq);
 966}
 967
 968/**
 969 * scsi_init_io - SCSI I/O initialization function.
 970 * @cmd:  command descriptor we wish to initialize
 971 *
 972 * Returns:
 973 * * BLK_STS_OK       - on success
 974 * * BLK_STS_RESOURCE - if the failure is retryable
 975 * * BLK_STS_IOERR    - if the failure is fatal
 
 976 */
 977blk_status_t scsi_init_io(struct scsi_cmnd *cmd)
 978{
 979	struct scsi_device *sdev = cmd->device;
 980	struct request *rq = cmd->request;
 981	unsigned short nr_segs = blk_rq_nr_phys_segments(rq);
 982	struct scatterlist *last_sg = NULL;
 983	blk_status_t ret;
 984	bool need_drain = scsi_cmd_needs_dma_drain(sdev, rq);
 985	int count;
 986
 987	if (WARN_ON_ONCE(!nr_segs))
 988		return BLK_STS_IOERR;
 989
 990	/*
 991	 * Make sure there is space for the drain.  The driver must adjust
 992	 * max_hw_segments to be prepared for this.
 993	 */
 994	if (need_drain)
 995		nr_segs++;
 996
 997	/*
 998	 * If sg table allocation fails, requeue request later.
 999	 */
1000	if (unlikely(sg_alloc_table_chained(&cmd->sdb.table, nr_segs,
1001			cmd->sdb.table.sgl, SCSI_INLINE_SG_CNT)))
1002		return BLK_STS_RESOURCE;
1003
1004	/*
1005	 * Next, walk the list, and fill in the addresses and sizes of
1006	 * each segment.
1007	 */
1008	count = __blk_rq_map_sg(rq->q, rq, cmd->sdb.table.sgl, &last_sg);
1009
1010	if (blk_rq_bytes(rq) & rq->q->dma_pad_mask) {
1011		unsigned int pad_len =
1012			(rq->q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1;
1013
1014		last_sg->length += pad_len;
1015		cmd->extra_len += pad_len;
1016	}
 
 
 
 
 
 
 
 
 
1017
1018	if (need_drain) {
1019		sg_unmark_end(last_sg);
1020		last_sg = sg_next(last_sg);
1021		sg_set_buf(last_sg, sdev->dma_drain_buf, sdev->dma_drain_len);
1022		sg_mark_end(last_sg);
1023
1024		cmd->extra_len += sdev->dma_drain_len;
1025		count++;
 
1026	}
1027
1028	BUG_ON(count > cmd->sdb.table.nents);
1029	cmd->sdb.table.nents = count;
1030	cmd->sdb.length = blk_rq_payload_bytes(rq);
1031
1032	if (blk_integrity_rq(rq)) {
1033		struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1034		int ivecs;
1035
1036		if (WARN_ON_ONCE(!prot_sdb)) {
1037			/*
1038			 * This can happen if someone (e.g. multipath)
1039			 * queues a command to a device on an adapter
1040			 * that does not support DIX.
1041			 */
1042			ret = BLK_STS_IOERR;
1043			goto out_free_sgtables;
 
1044		}
1045
1046		ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
1047
1048		if (sg_alloc_table_chained(&prot_sdb->table, ivecs,
1049				prot_sdb->table.sgl,
1050				SCSI_INLINE_PROT_SG_CNT)) {
1051			ret = BLK_STS_RESOURCE;
1052			goto out_free_sgtables;
1053		}
1054
1055		count = blk_rq_map_integrity_sg(rq->q, rq->bio,
1056						prot_sdb->table.sgl);
1057		BUG_ON(count > ivecs);
1058		BUG_ON(count > queue_max_integrity_segments(rq->q));
1059
1060		cmd->prot_sdb = prot_sdb;
1061		cmd->prot_sdb->table.nents = count;
1062	}
1063
1064	return BLK_STS_OK;
1065out_free_sgtables:
1066	scsi_free_sgtables(cmd);
1067	return ret;
1068}
1069EXPORT_SYMBOL(scsi_init_io);
1070
1071/**
1072 * scsi_initialize_rq - initialize struct scsi_cmnd partially
1073 * @rq: Request associated with the SCSI command to be initialized.
1074 *
1075 * This function initializes the members of struct scsi_cmnd that must be
1076 * initialized before request processing starts and that won't be
1077 * reinitialized if a SCSI command is requeued.
1078 *
1079 * Called from inside blk_get_request() for pass-through requests and from
1080 * inside scsi_init_command() for filesystem requests.
1081 */
1082static void scsi_initialize_rq(struct request *rq)
1083{
1084	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1085
1086	scsi_req_init(&cmd->req);
1087	init_rcu_head(&cmd->rcu);
1088	cmd->jiffies_at_alloc = jiffies;
1089	cmd->retries = 0;
1090}
1091
1092/*
1093 * Only called when the request isn't completed by SCSI, and not freed by
1094 * SCSI
1095 */
1096static void scsi_cleanup_rq(struct request *rq)
1097{
1098	if (rq->rq_flags & RQF_DONTPREP) {
1099		scsi_mq_uninit_cmd(blk_mq_rq_to_pdu(rq));
1100		rq->rq_flags &= ~RQF_DONTPREP;
1101	}
 
1102}
 
1103
1104/* Called before a request is prepared. See also scsi_mq_prep_fn(). */
1105void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd)
1106{
1107	void *buf = cmd->sense_buffer;
1108	void *prot = cmd->prot_sdb;
1109	struct request *rq = blk_mq_rq_from_pdu(cmd);
1110	unsigned int flags = cmd->flags & SCMD_PRESERVED_FLAGS;
1111	unsigned long jiffies_at_alloc;
1112	int retries, to_clear;
1113	bool in_flight;
1114
1115	if (!blk_rq_is_scsi(rq) && !(flags & SCMD_INITIALIZED)) {
1116		flags |= SCMD_INITIALIZED;
1117		scsi_initialize_rq(rq);
 
 
 
 
 
 
 
 
 
 
1118	}
1119
1120	jiffies_at_alloc = cmd->jiffies_at_alloc;
1121	retries = cmd->retries;
1122	in_flight = test_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1123	/*
1124	 * Zero out the cmd, except for the embedded scsi_request. Only clear
1125	 * the driver-private command data if the LLD does not supply a
1126	 * function to initialize that data.
1127	 */
1128	to_clear = sizeof(*cmd) - sizeof(cmd->req);
1129	if (!dev->host->hostt->init_cmd_priv)
1130		to_clear += dev->host->hostt->cmd_size;
1131	memset((char *)cmd + sizeof(cmd->req), 0, to_clear);
1132
1133	cmd->device = dev;
1134	cmd->sense_buffer = buf;
1135	cmd->prot_sdb = prot;
1136	cmd->flags = flags;
1137	INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
1138	cmd->jiffies_at_alloc = jiffies_at_alloc;
1139	cmd->retries = retries;
1140	if (in_flight)
1141		__set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1142
 
1143}
1144
1145static blk_status_t scsi_setup_scsi_cmnd(struct scsi_device *sdev,
1146		struct request *req)
1147{
1148	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1149
1150	/*
1151	 * Passthrough requests may transfer data, in which case they must
1152	 * a bio attached to them.  Or they might contain a SCSI command
1153	 * that does not transfer data, in which case they may optionally
1154	 * submit a request without an attached bio.
1155	 */
1156	if (req->bio) {
1157		blk_status_t ret = scsi_init_io(cmd);
1158		if (unlikely(ret != BLK_STS_OK))
1159			return ret;
1160	} else {
1161		BUG_ON(blk_rq_bytes(req));
1162
1163		memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1164	}
1165
1166	cmd->cmd_len = scsi_req(req)->cmd_len;
1167	cmd->cmnd = scsi_req(req)->cmd;
1168	cmd->transfersize = blk_rq_bytes(req);
1169	cmd->allowed = scsi_req(req)->retries;
1170	return BLK_STS_OK;
1171}
1172
1173/*
1174 * Setup a normal block command.  These are simple request from filesystems
1175 * that still need to be translated to SCSI CDBs from the ULD.
1176 */
1177static blk_status_t scsi_setup_fs_cmnd(struct scsi_device *sdev,
1178		struct request *req)
1179{
1180	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1181
1182	if (unlikely(sdev->handler && sdev->handler->prep_fn)) {
1183		blk_status_t ret = sdev->handler->prep_fn(sdev, req);
1184		if (ret != BLK_STS_OK)
1185			return ret;
1186	}
1187
1188	cmd->cmnd = scsi_req(req)->cmd = scsi_req(req)->__cmd;
1189	memset(cmd->cmnd, 0, BLK_MAX_CDB);
1190	return scsi_cmd_to_driver(cmd)->init_command(cmd);
1191}
1192
1193static blk_status_t scsi_setup_cmnd(struct scsi_device *sdev,
1194		struct request *req)
1195{
1196	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1197	blk_status_t ret;
1198
1199	if (!blk_rq_bytes(req))
1200		cmd->sc_data_direction = DMA_NONE;
1201	else if (rq_data_dir(req) == WRITE)
1202		cmd->sc_data_direction = DMA_TO_DEVICE;
1203	else
1204		cmd->sc_data_direction = DMA_FROM_DEVICE;
1205
1206	if (blk_rq_is_scsi(req))
1207		ret = scsi_setup_scsi_cmnd(sdev, req);
1208	else
1209		ret = scsi_setup_fs_cmnd(sdev, req);
1210
1211	if (ret != BLK_STS_OK)
1212		scsi_free_sgtables(cmd);
1213
1214	return ret;
1215}
1216
1217static blk_status_t
1218scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
1219{
1220	switch (sdev->sdev_state) {
1221	case SDEV_OFFLINE:
1222	case SDEV_TRANSPORT_OFFLINE:
1223		/*
1224		 * If the device is offline we refuse to process any
1225		 * commands.  The device must be brought online
1226		 * before trying any recovery commands.
1227		 */
1228		if (!sdev->offline_already) {
1229			sdev->offline_already = true;
 
 
 
 
 
1230			sdev_printk(KERN_ERR, sdev,
1231				    "rejecting I/O to offline device\n");
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1232		}
1233		return BLK_STS_IOERR;
1234	case SDEV_DEL:
1235		/*
1236		 * If the device is fully deleted, we refuse to
1237		 * process any commands as well.
1238		 */
1239		sdev_printk(KERN_ERR, sdev,
1240			    "rejecting I/O to dead device\n");
1241		return BLK_STS_IOERR;
1242	case SDEV_BLOCK:
1243	case SDEV_CREATED_BLOCK:
1244		return BLK_STS_RESOURCE;
1245	case SDEV_QUIESCE:
 
 
 
 
 
 
 
 
 
 
1246		/*
1247		 * If the devices is blocked we defer normal commands.
 
 
1248		 */
1249		if (req && !(req->rq_flags & RQF_PREEMPT))
1250			return BLK_STS_RESOURCE;
1251		return BLK_STS_OK;
1252	default:
1253		/*
1254		 * For any other not fully online state we only allow
1255		 * special commands.  In particular any user initiated
1256		 * command is not allowed.
1257		 */
1258		if (req && !(req->rq_flags & RQF_PREEMPT))
1259			return BLK_STS_IOERR;
1260		return BLK_STS_OK;
1261	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1262}
1263
1264/*
1265 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1266 * return 0.
1267 *
1268 * Called with the queue_lock held.
1269 */
1270static inline int scsi_dev_queue_ready(struct request_queue *q,
1271				  struct scsi_device *sdev)
1272{
1273	unsigned int busy;
1274
1275	busy = atomic_inc_return(&sdev->device_busy) - 1;
1276	if (atomic_read(&sdev->device_blocked)) {
1277		if (busy)
1278			goto out_dec;
1279
1280		/*
1281		 * unblock after device_blocked iterates to zero
1282		 */
1283		if (atomic_dec_return(&sdev->device_blocked) > 0)
 
 
 
 
 
1284			goto out_dec;
 
1285		SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev,
1286				   "unblocking device at zero depth\n"));
1287	}
1288
1289	if (busy >= sdev->queue_depth)
1290		goto out_dec;
1291
1292	return 1;
1293out_dec:
1294	atomic_dec(&sdev->device_busy);
1295	return 0;
1296}
1297
1298/*
1299 * scsi_target_queue_ready: checks if there we can send commands to target
1300 * @sdev: scsi device on starget to check.
1301 */
1302static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1303					   struct scsi_device *sdev)
1304{
1305	struct scsi_target *starget = scsi_target(sdev);
1306	unsigned int busy;
1307
1308	if (starget->single_lun) {
1309		spin_lock_irq(shost->host_lock);
1310		if (starget->starget_sdev_user &&
1311		    starget->starget_sdev_user != sdev) {
1312			spin_unlock_irq(shost->host_lock);
1313			return 0;
1314		}
1315		starget->starget_sdev_user = sdev;
1316		spin_unlock_irq(shost->host_lock);
1317	}
1318
1319	if (starget->can_queue <= 0)
1320		return 1;
1321
1322	busy = atomic_inc_return(&starget->target_busy) - 1;
1323	if (atomic_read(&starget->target_blocked) > 0) {
1324		if (busy)
1325			goto starved;
1326
1327		/*
1328		 * unblock after target_blocked iterates to zero
1329		 */
1330		if (atomic_dec_return(&starget->target_blocked) > 0)
1331			goto out_dec;
1332
1333		SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1334				 "unblocking target at zero depth\n"));
1335	}
1336
1337	if (busy >= starget->can_queue)
1338		goto starved;
1339
1340	return 1;
1341
1342starved:
1343	spin_lock_irq(shost->host_lock);
1344	list_move_tail(&sdev->starved_entry, &shost->starved_list);
1345	spin_unlock_irq(shost->host_lock);
1346out_dec:
1347	if (starget->can_queue > 0)
1348		atomic_dec(&starget->target_busy);
1349	return 0;
1350}
1351
1352/*
1353 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1354 * return 0. We must end up running the queue again whenever 0 is
1355 * returned, else IO can hang.
1356 */
1357static inline int scsi_host_queue_ready(struct request_queue *q,
1358				   struct Scsi_Host *shost,
1359				   struct scsi_device *sdev,
1360				   struct scsi_cmnd *cmd)
1361{
 
 
1362	if (scsi_host_in_recovery(shost))
1363		return 0;
1364
 
1365	if (atomic_read(&shost->host_blocked) > 0) {
1366		if (scsi_host_busy(shost) > 0)
1367			goto starved;
1368
1369		/*
1370		 * unblock after host_blocked iterates to zero
1371		 */
1372		if (atomic_dec_return(&shost->host_blocked) > 0)
1373			goto out_dec;
1374
1375		SCSI_LOG_MLQUEUE(3,
1376			shost_printk(KERN_INFO, shost,
1377				     "unblocking host at zero depth\n"));
1378	}
1379
 
 
1380	if (shost->host_self_blocked)
1381		goto starved;
1382
1383	/* We're OK to process the command, so we can't be starved */
1384	if (!list_empty(&sdev->starved_entry)) {
1385		spin_lock_irq(shost->host_lock);
1386		if (!list_empty(&sdev->starved_entry))
1387			list_del_init(&sdev->starved_entry);
1388		spin_unlock_irq(shost->host_lock);
1389	}
1390
1391	__set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1392
1393	return 1;
1394
1395starved:
1396	spin_lock_irq(shost->host_lock);
1397	if (list_empty(&sdev->starved_entry))
1398		list_add_tail(&sdev->starved_entry, &shost->starved_list);
1399	spin_unlock_irq(shost->host_lock);
1400out_dec:
1401	scsi_dec_host_busy(shost, cmd);
1402	return 0;
1403}
1404
1405/*
1406 * Busy state exporting function for request stacking drivers.
1407 *
1408 * For efficiency, no lock is taken to check the busy state of
1409 * shost/starget/sdev, since the returned value is not guaranteed and
1410 * may be changed after request stacking drivers call the function,
1411 * regardless of taking lock or not.
1412 *
1413 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1414 * needs to return 'not busy'. Otherwise, request stacking drivers
1415 * may hold requests forever.
1416 */
1417static bool scsi_mq_lld_busy(struct request_queue *q)
1418{
1419	struct scsi_device *sdev = q->queuedata;
1420	struct Scsi_Host *shost;
1421
1422	if (blk_queue_dying(q))
1423		return false;
1424
1425	shost = sdev->host;
1426
1427	/*
1428	 * Ignore host/starget busy state.
1429	 * Since block layer does not have a concept of fairness across
1430	 * multiple queues, congestion of host/starget needs to be handled
1431	 * in SCSI layer.
1432	 */
1433	if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
1434		return true;
1435
1436	return false;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1437}
1438
1439static void scsi_softirq_done(struct request *rq)
1440{
1441	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1442	unsigned long wait_for = (cmd->allowed + 1) * rq->timeout;
1443	int disposition;
1444
1445	INIT_LIST_HEAD(&cmd->eh_entry);
1446
1447	atomic_inc(&cmd->device->iodone_cnt);
1448	if (cmd->result)
1449		atomic_inc(&cmd->device->ioerr_cnt);
1450
1451	disposition = scsi_decide_disposition(cmd);
1452	if (disposition != SUCCESS &&
1453	    time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
1454		scmd_printk(KERN_ERR, cmd,
1455			    "timing out command, waited %lus\n",
1456			    wait_for/HZ);
1457		disposition = SUCCESS;
1458	}
1459
1460	scsi_log_completion(cmd, disposition);
1461
1462	switch (disposition) {
1463	case SUCCESS:
1464		scsi_finish_command(cmd);
1465		break;
1466	case NEEDS_RETRY:
1467		scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
1468		break;
1469	case ADD_TO_MLQUEUE:
1470		scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1471		break;
1472	default:
1473		scsi_eh_scmd_add(cmd);
1474		break;
1475	}
1476}
1477
1478/**
1479 * scsi_dispatch_command - Dispatch a command to the low-level driver.
1480 * @cmd: command block we are dispatching.
1481 *
1482 * Return: nonzero return request was rejected and device's queue needs to be
1483 * plugged.
1484 */
1485static int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
1486{
1487	struct Scsi_Host *host = cmd->device->host;
1488	int rtn = 0;
1489
1490	atomic_inc(&cmd->device->iorequest_cnt);
1491
1492	/* check if the device is still usable */
1493	if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
1494		/* in SDEV_DEL we error all commands. DID_NO_CONNECT
1495		 * returns an immediate error upwards, and signals
1496		 * that the device is no longer present */
1497		cmd->result = DID_NO_CONNECT << 16;
1498		goto done;
1499	}
1500
1501	/* Check to see if the scsi lld made this device blocked. */
1502	if (unlikely(scsi_device_blocked(cmd->device))) {
1503		/*
1504		 * in blocked state, the command is just put back on
1505		 * the device queue.  The suspend state has already
1506		 * blocked the queue so future requests should not
1507		 * occur until the device transitions out of the
1508		 * suspend state.
1509		 */
1510		SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1511			"queuecommand : device blocked\n"));
1512		return SCSI_MLQUEUE_DEVICE_BUSY;
1513	}
1514
1515	/* Store the LUN value in cmnd, if needed. */
1516	if (cmd->device->lun_in_cdb)
1517		cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
1518			       (cmd->device->lun << 5 & 0xe0);
1519
1520	scsi_log_send(cmd);
1521
1522	/*
1523	 * Before we queue this command, check if the command
1524	 * length exceeds what the host adapter can handle.
1525	 */
1526	if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
1527		SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1528			       "queuecommand : command too long. "
1529			       "cdb_size=%d host->max_cmd_len=%d\n",
1530			       cmd->cmd_len, cmd->device->host->max_cmd_len));
1531		cmd->result = (DID_ABORT << 16);
1532		goto done;
1533	}
1534
1535	if (unlikely(host->shost_state == SHOST_DEL)) {
1536		cmd->result = (DID_NO_CONNECT << 16);
1537		goto done;
1538
1539	}
1540
1541	trace_scsi_dispatch_cmd_start(cmd);
1542	rtn = host->hostt->queuecommand(host, cmd);
1543	if (rtn) {
1544		trace_scsi_dispatch_cmd_error(cmd, rtn);
1545		if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
1546		    rtn != SCSI_MLQUEUE_TARGET_BUSY)
1547			rtn = SCSI_MLQUEUE_HOST_BUSY;
1548
1549		SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1550			"queuecommand : request rejected\n"));
1551	}
1552
1553	return rtn;
1554 done:
1555	cmd->scsi_done(cmd);
1556	return 0;
1557}
1558
1559/* Size in bytes of the sg-list stored in the scsi-mq command-private data. */
1560static unsigned int scsi_mq_inline_sgl_size(struct Scsi_Host *shost)
 
 
 
 
 
 
 
 
 
 
1561{
1562	return min_t(unsigned int, shost->sg_tablesize, SCSI_INLINE_SG_CNT) *
1563		sizeof(struct scatterlist);
1564}
1565
1566static blk_status_t scsi_mq_prep_fn(struct request *req)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1567{
1568	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1569	struct scsi_device *sdev = req->q->queuedata;
1570	struct Scsi_Host *shost = sdev->host;
 
1571	struct scatterlist *sg;
1572
1573	scsi_init_command(sdev, cmd);
 
 
1574
1575	cmd->request = req;
 
 
 
1576	cmd->tag = req->tag;
 
 
1577	cmd->prot_op = SCSI_PROT_NORMAL;
1578
 
 
 
 
 
 
 
 
 
 
1579	sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
1580	cmd->sdb.table.sgl = sg;
1581
1582	if (scsi_host_get_prot(shost)) {
 
 
 
 
1583		memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer));
1584
1585		cmd->prot_sdb->table.sgl =
1586			(struct scatterlist *)(cmd->prot_sdb + 1);
1587	}
1588
 
 
 
 
 
 
 
 
 
 
 
1589	blk_mq_start_request(req);
1590
1591	return scsi_setup_cmnd(sdev, req);
1592}
1593
1594static void scsi_mq_done(struct scsi_cmnd *cmd)
1595{
1596	if (unlikely(blk_should_fake_timeout(cmd->request->q)))
1597		return;
1598	if (unlikely(test_and_set_bit(SCMD_STATE_COMPLETE, &cmd->state)))
1599		return;
1600	trace_scsi_dispatch_cmd_done(cmd);
1601	blk_mq_complete_request(cmd->request);
1602}
1603
1604static void scsi_mq_put_budget(struct request_queue *q)
1605{
1606	struct scsi_device *sdev = q->queuedata;
1607
1608	atomic_dec(&sdev->device_busy);
1609}
1610
1611static bool scsi_mq_get_budget(struct request_queue *q)
1612{
1613	struct scsi_device *sdev = q->queuedata;
1614
1615	return scsi_dev_queue_ready(q, sdev);
1616}
1617
1618static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
1619			 const struct blk_mq_queue_data *bd)
1620{
1621	struct request *req = bd->rq;
1622	struct request_queue *q = req->q;
1623	struct scsi_device *sdev = q->queuedata;
1624	struct Scsi_Host *shost = sdev->host;
1625	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1626	blk_status_t ret;
1627	int reason;
1628
1629	/*
1630	 * If the device is not in running state we will reject some or all
1631	 * commands.
1632	 */
1633	if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
1634		ret = scsi_prep_state_check(sdev, req);
1635		if (ret != BLK_STS_OK)
1636			goto out_put_budget;
1637	}
1638
1639	ret = BLK_STS_RESOURCE;
 
1640	if (!scsi_target_queue_ready(shost, sdev))
1641		goto out_put_budget;
1642	if (!scsi_host_queue_ready(q, shost, sdev, cmd))
1643		goto out_dec_target_busy;
1644
1645	if (!(req->rq_flags & RQF_DONTPREP)) {
1646		ret = scsi_mq_prep_fn(req);
1647		if (ret != BLK_STS_OK)
 
1648			goto out_dec_host_busy;
1649		req->rq_flags |= RQF_DONTPREP;
1650	} else {
1651		clear_bit(SCMD_STATE_COMPLETE, &cmd->state);
1652		blk_mq_start_request(req);
1653	}
1654
1655	cmd->flags &= SCMD_PRESERVED_FLAGS;
1656	if (sdev->simple_tags)
1657		cmd->flags |= SCMD_TAGGED;
1658	if (bd->last)
1659		cmd->flags |= SCMD_LAST;
1660
1661	scsi_init_cmd_errh(cmd);
1662	cmd->scsi_done = scsi_mq_done;
1663
1664	reason = scsi_dispatch_cmd(cmd);
1665	if (reason) {
1666		scsi_set_blocked(cmd, reason);
1667		ret = BLK_STS_RESOURCE;
1668		goto out_dec_host_busy;
1669	}
1670
1671	return BLK_STS_OK;
1672
1673out_dec_host_busy:
1674	scsi_dec_host_busy(shost, cmd);
1675out_dec_target_busy:
1676	if (scsi_target(sdev)->can_queue > 0)
1677		atomic_dec(&scsi_target(sdev)->target_busy);
1678out_put_budget:
1679	scsi_mq_put_budget(q);
 
 
 
1680	switch (ret) {
1681	case BLK_STS_OK:
 
 
 
 
1682		break;
1683	case BLK_STS_RESOURCE:
1684	case BLK_STS_ZONE_RESOURCE:
1685		if (atomic_read(&sdev->device_busy) ||
1686		    scsi_device_blocked(sdev))
1687			ret = BLK_STS_DEV_RESOURCE;
1688		break;
1689	default:
1690		if (unlikely(!scsi_device_online(sdev)))
1691			scsi_req(req)->result = DID_NO_CONNECT << 16;
1692		else
1693			scsi_req(req)->result = DID_ERROR << 16;
1694		/*
1695		 * Make sure to release all allocated resources when
1696		 * we hit an error, as we will never see this command
1697		 * again.
1698		 */
1699		if (req->rq_flags & RQF_DONTPREP)
1700			scsi_mq_uninit_cmd(cmd);
1701		scsi_run_queue_async(sdev);
 
1702		break;
1703	}
1704	return ret;
1705}
1706
1707static enum blk_eh_timer_return scsi_timeout(struct request *req,
1708		bool reserved)
1709{
1710	if (reserved)
1711		return BLK_EH_RESET_TIMER;
1712	return scsi_times_out(req);
1713}
1714
1715static int scsi_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
1716				unsigned int hctx_idx, unsigned int numa_node)
 
1717{
1718	struct Scsi_Host *shost = set->driver_data;
1719	const bool unchecked_isa_dma = shost->unchecked_isa_dma;
1720	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1721	struct scatterlist *sg;
1722	int ret = 0;
1723
1724	if (unchecked_isa_dma)
1725		cmd->flags |= SCMD_UNCHECKED_ISA_DMA;
1726	cmd->sense_buffer = scsi_alloc_sense_buffer(unchecked_isa_dma,
1727						    GFP_KERNEL, numa_node);
1728	if (!cmd->sense_buffer)
1729		return -ENOMEM;
1730	cmd->req.sense = cmd->sense_buffer;
1731
1732	if (scsi_host_get_prot(shost)) {
1733		sg = (void *)cmd + sizeof(struct scsi_cmnd) +
1734			shost->hostt->cmd_size;
1735		cmd->prot_sdb = (void *)sg + scsi_mq_inline_sgl_size(shost);
1736	}
1737
1738	if (shost->hostt->init_cmd_priv) {
1739		ret = shost->hostt->init_cmd_priv(shost, cmd);
1740		if (ret < 0)
1741			scsi_free_sense_buffer(unchecked_isa_dma,
1742					       cmd->sense_buffer);
1743	}
1744
1745	return ret;
1746}
1747
1748static void scsi_mq_exit_request(struct blk_mq_tag_set *set, struct request *rq,
1749				 unsigned int hctx_idx)
1750{
1751	struct Scsi_Host *shost = set->driver_data;
1752	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1753
1754	if (shost->hostt->exit_cmd_priv)
1755		shost->hostt->exit_cmd_priv(shost, cmd);
1756	scsi_free_sense_buffer(cmd->flags & SCMD_UNCHECKED_ISA_DMA,
1757			       cmd->sense_buffer);
1758}
1759
1760static int scsi_map_queues(struct blk_mq_tag_set *set)
1761{
1762	struct Scsi_Host *shost = container_of(set, struct Scsi_Host, tag_set);
 
1763
1764	if (shost->hostt->map_queues)
1765		return shost->hostt->map_queues(shost);
1766	return blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]);
 
 
 
 
 
 
 
 
 
 
 
1767}
1768
1769void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
1770{
1771	struct device *dev = shost->dma_dev;
1772
1773	/*
1774	 * this limit is imposed by hardware restrictions
1775	 */
1776	blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
1777					SG_MAX_SEGMENTS));
1778
1779	if (scsi_host_prot_dma(shost)) {
1780		shost->sg_prot_tablesize =
1781			min_not_zero(shost->sg_prot_tablesize,
1782				     (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
1783		BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
1784		blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
1785	}
1786
1787	if (dev->dma_mask) {
1788		shost->max_sectors = min_t(unsigned int, shost->max_sectors,
1789				dma_max_mapping_size(dev) >> SECTOR_SHIFT);
1790	}
1791	blk_queue_max_hw_sectors(q, shost->max_sectors);
1792	if (shost->unchecked_isa_dma)
1793		blk_queue_bounce_limit(q, BLK_BOUNCE_ISA);
1794	blk_queue_segment_boundary(q, shost->dma_boundary);
1795	dma_set_seg_boundary(dev, shost->dma_boundary);
1796
1797	blk_queue_max_segment_size(q, shost->max_segment_size);
1798	blk_queue_virt_boundary(q, shost->virt_boundary_mask);
1799	dma_set_max_seg_size(dev, queue_max_segment_size(q));
 
1800
1801	/*
1802	 * Set a reasonable default alignment:  The larger of 32-byte (dword),
1803	 * which is a common minimum for HBAs, and the minimum DMA alignment,
1804	 * which is set by the platform.
1805	 *
1806	 * Devices that require a bigger alignment can increase it later.
1807	 */
1808	blk_queue_dma_alignment(q, max(4, dma_get_cache_alignment()) - 1);
1809}
1810EXPORT_SYMBOL_GPL(__scsi_init_queue);
1811
1812static const struct blk_mq_ops scsi_mq_ops_no_commit = {
1813	.get_budget	= scsi_mq_get_budget,
1814	.put_budget	= scsi_mq_put_budget,
1815	.queue_rq	= scsi_queue_rq,
1816	.complete	= scsi_softirq_done,
1817	.timeout	= scsi_timeout,
1818#ifdef CONFIG_BLK_DEBUG_FS
1819	.show_rq	= scsi_show_rq,
1820#endif
1821	.init_request	= scsi_mq_init_request,
1822	.exit_request	= scsi_mq_exit_request,
1823	.initialize_rq_fn = scsi_initialize_rq,
1824	.cleanup_rq	= scsi_cleanup_rq,
1825	.busy		= scsi_mq_lld_busy,
1826	.map_queues	= scsi_map_queues,
1827};
1828
 
 
 
 
 
 
 
1829
1830static void scsi_commit_rqs(struct blk_mq_hw_ctx *hctx)
1831{
1832	struct request_queue *q = hctx->queue;
1833	struct scsi_device *sdev = q->queuedata;
1834	struct Scsi_Host *shost = sdev->host;
1835
1836	shost->hostt->commit_rqs(shost, hctx->queue_num);
 
 
 
 
 
 
 
 
 
1837}
1838
1839static const struct blk_mq_ops scsi_mq_ops = {
1840	.get_budget	= scsi_mq_get_budget,
1841	.put_budget	= scsi_mq_put_budget,
1842	.queue_rq	= scsi_queue_rq,
1843	.commit_rqs	= scsi_commit_rqs,
1844	.complete	= scsi_softirq_done,
1845	.timeout	= scsi_timeout,
1846#ifdef CONFIG_BLK_DEBUG_FS
1847	.show_rq	= scsi_show_rq,
1848#endif
1849	.init_request	= scsi_mq_init_request,
1850	.exit_request	= scsi_mq_exit_request,
1851	.initialize_rq_fn = scsi_initialize_rq,
1852	.cleanup_rq	= scsi_cleanup_rq,
1853	.busy		= scsi_mq_lld_busy,
1854	.map_queues	= scsi_map_queues,
1855};
1856
1857struct request_queue *scsi_mq_alloc_queue(struct scsi_device *sdev)
1858{
1859	sdev->request_queue = blk_mq_init_queue(&sdev->host->tag_set);
1860	if (IS_ERR(sdev->request_queue))
1861		return NULL;
1862
1863	sdev->request_queue->queuedata = sdev;
1864	__scsi_init_queue(sdev->host, sdev->request_queue);
1865	blk_queue_flag_set(QUEUE_FLAG_SCSI_PASSTHROUGH, sdev->request_queue);
1866	return sdev->request_queue;
1867}
1868
1869int scsi_mq_setup_tags(struct Scsi_Host *shost)
1870{
1871	unsigned int cmd_size, sgl_size;
1872	struct blk_mq_tag_set *tag_set = &shost->tag_set;
1873
1874	sgl_size = max_t(unsigned int, sizeof(struct scatterlist),
1875				scsi_mq_inline_sgl_size(shost));
 
 
1876	cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size;
1877	if (scsi_host_get_prot(shost))
1878		cmd_size += sizeof(struct scsi_data_buffer) +
1879			sizeof(struct scatterlist) * SCSI_INLINE_PROT_SG_CNT;
1880
1881	memset(tag_set, 0, sizeof(*tag_set));
1882	if (shost->hostt->commit_rqs)
1883		tag_set->ops = &scsi_mq_ops;
1884	else
1885		tag_set->ops = &scsi_mq_ops_no_commit;
1886	tag_set->nr_hw_queues = shost->nr_hw_queues ? : 1;
1887	tag_set->queue_depth = shost->can_queue;
1888	tag_set->cmd_size = cmd_size;
1889	tag_set->numa_node = NUMA_NO_NODE;
1890	tag_set->flags = BLK_MQ_F_SHOULD_MERGE;
1891	tag_set->flags |=
1892		BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
1893	tag_set->driver_data = shost;
1894
1895	return blk_mq_alloc_tag_set(tag_set);
1896}
1897
1898void scsi_mq_destroy_tags(struct Scsi_Host *shost)
1899{
1900	blk_mq_free_tag_set(&shost->tag_set);
1901}
1902
1903/**
1904 * scsi_device_from_queue - return sdev associated with a request_queue
1905 * @q: The request queue to return the sdev from
1906 *
1907 * Return the sdev associated with a request queue or NULL if the
1908 * request_queue does not reference a SCSI device.
1909 */
1910struct scsi_device *scsi_device_from_queue(struct request_queue *q)
1911{
1912	struct scsi_device *sdev = NULL;
1913
1914	if (q->mq_ops == &scsi_mq_ops_no_commit ||
1915	    q->mq_ops == &scsi_mq_ops)
1916		sdev = q->queuedata;
1917	if (!sdev || !get_device(&sdev->sdev_gendev))
1918		sdev = NULL;
1919
1920	return sdev;
1921}
1922EXPORT_SYMBOL_GPL(scsi_device_from_queue);
1923
1924/**
1925 * scsi_block_requests - Utility function used by low-level drivers to prevent
1926 * further commands from being queued to the device.
1927 * @shost:  host in question
1928 *
1929 * There is no timer nor any other means by which the requests get unblocked
1930 * other than the low-level driver calling scsi_unblock_requests().
 
 
 
1931 */
1932void scsi_block_requests(struct Scsi_Host *shost)
1933{
1934	shost->host_self_blocked = 1;
1935}
1936EXPORT_SYMBOL(scsi_block_requests);
1937
1938/**
1939 * scsi_unblock_requests - Utility function used by low-level drivers to allow
1940 * further commands to be queued to the device.
1941 * @shost:  host in question
1942 *
1943 * There is no timer nor any other means by which the requests get unblocked
1944 * other than the low-level driver calling scsi_unblock_requests(). This is done
1945 * as an API function so that changes to the internals of the scsi mid-layer
1946 * won't require wholesale changes to drivers that use this feature.
 
 
 
 
 
 
 
 
 
 
1947 */
1948void scsi_unblock_requests(struct Scsi_Host *shost)
1949{
1950	shost->host_self_blocked = 0;
1951	scsi_run_host_queues(shost);
1952}
1953EXPORT_SYMBOL(scsi_unblock_requests);
1954
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1955void scsi_exit_queue(void)
1956{
1957	kmem_cache_destroy(scsi_sense_cache);
1958	kmem_cache_destroy(scsi_sense_isadma_cache);
 
 
 
 
 
 
 
1959}
1960
1961/**
1962 *	scsi_mode_select - issue a mode select
1963 *	@sdev:	SCSI device to be queried
1964 *	@pf:	Page format bit (1 == standard, 0 == vendor specific)
1965 *	@sp:	Save page bit (0 == don't save, 1 == save)
1966 *	@modepage: mode page being requested
1967 *	@buffer: request buffer (may not be smaller than eight bytes)
1968 *	@len:	length of request buffer.
1969 *	@timeout: command timeout
1970 *	@retries: number of retries before failing
1971 *	@data: returns a structure abstracting the mode header data
1972 *	@sshdr: place to put sense data (or NULL if no sense to be collected).
1973 *		must be SCSI_SENSE_BUFFERSIZE big.
1974 *
1975 *	Returns zero if successful; negative error number or scsi
1976 *	status on error
1977 *
1978 */
1979int
1980scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
1981		 unsigned char *buffer, int len, int timeout, int retries,
1982		 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
1983{
1984	unsigned char cmd[10];
1985	unsigned char *real_buffer;
1986	int ret;
1987
1988	memset(cmd, 0, sizeof(cmd));
1989	cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
1990
1991	if (sdev->use_10_for_ms) {
1992		if (len > 65535)
1993			return -EINVAL;
1994		real_buffer = kmalloc(8 + len, GFP_KERNEL);
1995		if (!real_buffer)
1996			return -ENOMEM;
1997		memcpy(real_buffer + 8, buffer, len);
1998		len += 8;
1999		real_buffer[0] = 0;
2000		real_buffer[1] = 0;
2001		real_buffer[2] = data->medium_type;
2002		real_buffer[3] = data->device_specific;
2003		real_buffer[4] = data->longlba ? 0x01 : 0;
2004		real_buffer[5] = 0;
2005		real_buffer[6] = data->block_descriptor_length >> 8;
2006		real_buffer[7] = data->block_descriptor_length;
2007
2008		cmd[0] = MODE_SELECT_10;
2009		cmd[7] = len >> 8;
2010		cmd[8] = len;
2011	} else {
2012		if (len > 255 || data->block_descriptor_length > 255 ||
2013		    data->longlba)
2014			return -EINVAL;
2015
2016		real_buffer = kmalloc(4 + len, GFP_KERNEL);
2017		if (!real_buffer)
2018			return -ENOMEM;
2019		memcpy(real_buffer + 4, buffer, len);
2020		len += 4;
2021		real_buffer[0] = 0;
2022		real_buffer[1] = data->medium_type;
2023		real_buffer[2] = data->device_specific;
2024		real_buffer[3] = data->block_descriptor_length;
 
2025
2026		cmd[0] = MODE_SELECT;
2027		cmd[4] = len;
2028	}
2029
2030	ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
2031			       sshdr, timeout, retries, NULL);
2032	kfree(real_buffer);
2033	return ret;
2034}
2035EXPORT_SYMBOL_GPL(scsi_mode_select);
2036
2037/**
2038 *	scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
2039 *	@sdev:	SCSI device to be queried
2040 *	@dbd:	set if mode sense will allow block descriptors to be returned
2041 *	@modepage: mode page being requested
2042 *	@buffer: request buffer (may not be smaller than eight bytes)
2043 *	@len:	length of request buffer.
2044 *	@timeout: command timeout
2045 *	@retries: number of retries before failing
2046 *	@data: returns a structure abstracting the mode header data
2047 *	@sshdr: place to put sense data (or NULL if no sense to be collected).
2048 *		must be SCSI_SENSE_BUFFERSIZE big.
2049 *
2050 *	Returns zero if unsuccessful, or the header offset (either 4
2051 *	or 8 depending on whether a six or ten byte command was
2052 *	issued) if successful.
2053 */
2054int
2055scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
2056		  unsigned char *buffer, int len, int timeout, int retries,
2057		  struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2058{
2059	unsigned char cmd[12];
2060	int use_10_for_ms;
2061	int header_length;
2062	int result, retry_count = retries;
2063	struct scsi_sense_hdr my_sshdr;
2064
2065	memset(data, 0, sizeof(*data));
2066	memset(&cmd[0], 0, 12);
2067
2068	dbd = sdev->set_dbd_for_ms ? 8 : dbd;
2069	cmd[1] = dbd & 0x18;	/* allows DBD and LLBA bits */
2070	cmd[2] = modepage;
2071
2072	/* caller might not be interested in sense, but we need it */
2073	if (!sshdr)
2074		sshdr = &my_sshdr;
2075
2076 retry:
2077	use_10_for_ms = sdev->use_10_for_ms;
2078
2079	if (use_10_for_ms) {
2080		if (len < 8)
2081			len = 8;
2082
2083		cmd[0] = MODE_SENSE_10;
2084		cmd[8] = len;
2085		header_length = 8;
2086	} else {
2087		if (len < 4)
2088			len = 4;
2089
2090		cmd[0] = MODE_SENSE;
2091		cmd[4] = len;
2092		header_length = 4;
2093	}
2094
2095	memset(buffer, 0, len);
2096
2097	result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
2098				  sshdr, timeout, retries, NULL);
2099
2100	/* This code looks awful: what it's doing is making sure an
2101	 * ILLEGAL REQUEST sense return identifies the actual command
2102	 * byte as the problem.  MODE_SENSE commands can return
2103	 * ILLEGAL REQUEST if the code page isn't supported */
2104
2105	if (use_10_for_ms && !scsi_status_is_good(result) &&
2106	    driver_byte(result) == DRIVER_SENSE) {
2107		if (scsi_sense_valid(sshdr)) {
2108			if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
2109			    (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
2110				/*
2111				 * Invalid command operation code
2112				 */
2113				sdev->use_10_for_ms = 0;
2114				goto retry;
2115			}
2116		}
2117	}
2118
2119	if (scsi_status_is_good(result)) {
2120		if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
2121			     (modepage == 6 || modepage == 8))) {
2122			/* Initio breakage? */
2123			header_length = 0;
2124			data->length = 13;
2125			data->medium_type = 0;
2126			data->device_specific = 0;
2127			data->longlba = 0;
2128			data->block_descriptor_length = 0;
2129		} else if (use_10_for_ms) {
2130			data->length = buffer[0]*256 + buffer[1] + 2;
2131			data->medium_type = buffer[2];
2132			data->device_specific = buffer[3];
2133			data->longlba = buffer[4] & 0x01;
2134			data->block_descriptor_length = buffer[6]*256
2135				+ buffer[7];
2136		} else {
2137			data->length = buffer[0] + 1;
2138			data->medium_type = buffer[1];
2139			data->device_specific = buffer[2];
2140			data->block_descriptor_length = buffer[3];
2141		}
2142		data->header_length = header_length;
2143	} else if ((status_byte(result) == CHECK_CONDITION) &&
2144		   scsi_sense_valid(sshdr) &&
2145		   sshdr->sense_key == UNIT_ATTENTION && retry_count) {
2146		retry_count--;
2147		goto retry;
2148	}
2149
2150	return result;
2151}
2152EXPORT_SYMBOL(scsi_mode_sense);
2153
2154/**
2155 *	scsi_test_unit_ready - test if unit is ready
2156 *	@sdev:	scsi device to change the state of.
2157 *	@timeout: command timeout
2158 *	@retries: number of retries before failing
2159 *	@sshdr: outpout pointer for decoded sense information.
 
 
2160 *
2161 *	Returns zero if unsuccessful or an error if TUR failed.  For
2162 *	removable media, UNIT_ATTENTION sets ->changed flag.
2163 **/
2164int
2165scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2166		     struct scsi_sense_hdr *sshdr)
2167{
2168	char cmd[] = {
2169		TEST_UNIT_READY, 0, 0, 0, 0, 0,
2170	};
 
2171	int result;
2172
 
 
 
 
 
2173	/* try to eat the UNIT_ATTENTION if there are enough retries */
2174	do {
2175		result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
2176					  timeout, 1, NULL);
2177		if (sdev->removable && scsi_sense_valid(sshdr) &&
2178		    sshdr->sense_key == UNIT_ATTENTION)
2179			sdev->changed = 1;
2180	} while (scsi_sense_valid(sshdr) &&
2181		 sshdr->sense_key == UNIT_ATTENTION && --retries);
2182
 
 
2183	return result;
2184}
2185EXPORT_SYMBOL(scsi_test_unit_ready);
2186
2187/**
2188 *	scsi_device_set_state - Take the given device through the device state model.
2189 *	@sdev:	scsi device to change the state of.
2190 *	@state:	state to change to.
2191 *
2192 *	Returns zero if successful or an error if the requested
2193 *	transition is illegal.
2194 */
2195int
2196scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2197{
2198	enum scsi_device_state oldstate = sdev->sdev_state;
2199
2200	if (state == oldstate)
2201		return 0;
2202
2203	switch (state) {
2204	case SDEV_CREATED:
2205		switch (oldstate) {
2206		case SDEV_CREATED_BLOCK:
2207			break;
2208		default:
2209			goto illegal;
2210		}
2211		break;
2212
2213	case SDEV_RUNNING:
2214		switch (oldstate) {
2215		case SDEV_CREATED:
2216		case SDEV_OFFLINE:
2217		case SDEV_TRANSPORT_OFFLINE:
2218		case SDEV_QUIESCE:
2219		case SDEV_BLOCK:
2220			break;
2221		default:
2222			goto illegal;
2223		}
2224		break;
2225
2226	case SDEV_QUIESCE:
2227		switch (oldstate) {
2228		case SDEV_RUNNING:
2229		case SDEV_OFFLINE:
2230		case SDEV_TRANSPORT_OFFLINE:
2231			break;
2232		default:
2233			goto illegal;
2234		}
2235		break;
2236
2237	case SDEV_OFFLINE:
2238	case SDEV_TRANSPORT_OFFLINE:
2239		switch (oldstate) {
2240		case SDEV_CREATED:
2241		case SDEV_RUNNING:
2242		case SDEV_QUIESCE:
2243		case SDEV_BLOCK:
2244			break;
2245		default:
2246			goto illegal;
2247		}
2248		break;
2249
2250	case SDEV_BLOCK:
2251		switch (oldstate) {
2252		case SDEV_RUNNING:
2253		case SDEV_CREATED_BLOCK:
2254		case SDEV_QUIESCE:
2255		case SDEV_OFFLINE:
2256			break;
2257		default:
2258			goto illegal;
2259		}
2260		break;
2261
2262	case SDEV_CREATED_BLOCK:
2263		switch (oldstate) {
2264		case SDEV_CREATED:
2265			break;
2266		default:
2267			goto illegal;
2268		}
2269		break;
2270
2271	case SDEV_CANCEL:
2272		switch (oldstate) {
2273		case SDEV_CREATED:
2274		case SDEV_RUNNING:
2275		case SDEV_QUIESCE:
2276		case SDEV_OFFLINE:
2277		case SDEV_TRANSPORT_OFFLINE:
 
2278			break;
2279		default:
2280			goto illegal;
2281		}
2282		break;
2283
2284	case SDEV_DEL:
2285		switch (oldstate) {
2286		case SDEV_CREATED:
2287		case SDEV_RUNNING:
2288		case SDEV_OFFLINE:
2289		case SDEV_TRANSPORT_OFFLINE:
2290		case SDEV_CANCEL:
2291		case SDEV_BLOCK:
2292		case SDEV_CREATED_BLOCK:
2293			break;
2294		default:
2295			goto illegal;
2296		}
2297		break;
2298
2299	}
2300	sdev->offline_already = false;
2301	sdev->sdev_state = state;
2302	return 0;
2303
2304 illegal:
2305	SCSI_LOG_ERROR_RECOVERY(1,
2306				sdev_printk(KERN_ERR, sdev,
2307					    "Illegal state transition %s->%s",
2308					    scsi_device_state_name(oldstate),
2309					    scsi_device_state_name(state))
2310				);
2311	return -EINVAL;
2312}
2313EXPORT_SYMBOL(scsi_device_set_state);
2314
2315/**
2316 * 	sdev_evt_emit - emit a single SCSI device uevent
2317 *	@sdev: associated SCSI device
2318 *	@evt: event to emit
2319 *
2320 *	Send a single uevent (scsi_event) to the associated scsi_device.
2321 */
2322static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2323{
2324	int idx = 0;
2325	char *envp[3];
2326
2327	switch (evt->evt_type) {
2328	case SDEV_EVT_MEDIA_CHANGE:
2329		envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2330		break;
2331	case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2332		scsi_rescan_device(&sdev->sdev_gendev);
2333		envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2334		break;
2335	case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2336		envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2337		break;
2338	case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2339	       envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2340		break;
2341	case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2342		envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2343		break;
2344	case SDEV_EVT_LUN_CHANGE_REPORTED:
2345		envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2346		break;
2347	case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2348		envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
2349		break;
2350	case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2351		envp[idx++] = "SDEV_UA=POWER_ON_RESET_OCCURRED";
2352		break;
2353	default:
2354		/* do nothing */
2355		break;
2356	}
2357
2358	envp[idx++] = NULL;
2359
2360	kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2361}
2362
2363/**
2364 * 	sdev_evt_thread - send a uevent for each scsi event
2365 *	@work: work struct for scsi_device
2366 *
2367 *	Dispatch queued events to their associated scsi_device kobjects
2368 *	as uevents.
2369 */
2370void scsi_evt_thread(struct work_struct *work)
2371{
2372	struct scsi_device *sdev;
2373	enum scsi_device_event evt_type;
2374	LIST_HEAD(event_list);
2375
2376	sdev = container_of(work, struct scsi_device, event_work);
2377
2378	for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
2379		if (test_and_clear_bit(evt_type, sdev->pending_events))
2380			sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
2381
2382	while (1) {
2383		struct scsi_event *evt;
2384		struct list_head *this, *tmp;
2385		unsigned long flags;
2386
2387		spin_lock_irqsave(&sdev->list_lock, flags);
2388		list_splice_init(&sdev->event_list, &event_list);
2389		spin_unlock_irqrestore(&sdev->list_lock, flags);
2390
2391		if (list_empty(&event_list))
2392			break;
2393
2394		list_for_each_safe(this, tmp, &event_list) {
2395			evt = list_entry(this, struct scsi_event, node);
2396			list_del(&evt->node);
2397			scsi_evt_emit(sdev, evt);
2398			kfree(evt);
2399		}
2400	}
2401}
2402
2403/**
2404 * 	sdev_evt_send - send asserted event to uevent thread
2405 *	@sdev: scsi_device event occurred on
2406 *	@evt: event to send
2407 *
2408 *	Assert scsi device event asynchronously.
2409 */
2410void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2411{
2412	unsigned long flags;
2413
2414#if 0
2415	/* FIXME: currently this check eliminates all media change events
2416	 * for polled devices.  Need to update to discriminate between AN
2417	 * and polled events */
2418	if (!test_bit(evt->evt_type, sdev->supported_events)) {
2419		kfree(evt);
2420		return;
2421	}
2422#endif
2423
2424	spin_lock_irqsave(&sdev->list_lock, flags);
2425	list_add_tail(&evt->node, &sdev->event_list);
2426	schedule_work(&sdev->event_work);
2427	spin_unlock_irqrestore(&sdev->list_lock, flags);
2428}
2429EXPORT_SYMBOL_GPL(sdev_evt_send);
2430
2431/**
2432 * 	sdev_evt_alloc - allocate a new scsi event
2433 *	@evt_type: type of event to allocate
2434 *	@gfpflags: GFP flags for allocation
2435 *
2436 *	Allocates and returns a new scsi_event.
2437 */
2438struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2439				  gfp_t gfpflags)
2440{
2441	struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2442	if (!evt)
2443		return NULL;
2444
2445	evt->evt_type = evt_type;
2446	INIT_LIST_HEAD(&evt->node);
2447
2448	/* evt_type-specific initialization, if any */
2449	switch (evt_type) {
2450	case SDEV_EVT_MEDIA_CHANGE:
2451	case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2452	case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2453	case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2454	case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2455	case SDEV_EVT_LUN_CHANGE_REPORTED:
2456	case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2457	case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2458	default:
2459		/* do nothing */
2460		break;
2461	}
2462
2463	return evt;
2464}
2465EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2466
2467/**
2468 * 	sdev_evt_send_simple - send asserted event to uevent thread
2469 *	@sdev: scsi_device event occurred on
2470 *	@evt_type: type of event to send
2471 *	@gfpflags: GFP flags for allocation
2472 *
2473 *	Assert scsi device event asynchronously, given an event type.
2474 */
2475void sdev_evt_send_simple(struct scsi_device *sdev,
2476			  enum scsi_device_event evt_type, gfp_t gfpflags)
2477{
2478	struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2479	if (!evt) {
2480		sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2481			    evt_type);
2482		return;
2483	}
2484
2485	sdev_evt_send(sdev, evt);
2486}
2487EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2488
2489/**
2490 *	scsi_device_quiesce - Block user issued commands.
2491 *	@sdev:	scsi device to quiesce.
2492 *
2493 *	This works by trying to transition to the SDEV_QUIESCE state
2494 *	(which must be a legal transition).  When the device is in this
2495 *	state, only special requests will be accepted, all others will
2496 *	be deferred.  Since special requests may also be requeued requests,
2497 *	a successful return doesn't guarantee the device will be
2498 *	totally quiescent.
2499 *
2500 *	Must be called with user context, may sleep.
2501 *
2502 *	Returns zero if unsuccessful or an error if not.
2503 */
2504int
2505scsi_device_quiesce(struct scsi_device *sdev)
2506{
2507	struct request_queue *q = sdev->request_queue;
2508	int err;
2509
2510	/*
2511	 * It is allowed to call scsi_device_quiesce() multiple times from
2512	 * the same context but concurrent scsi_device_quiesce() calls are
2513	 * not allowed.
2514	 */
2515	WARN_ON_ONCE(sdev->quiesced_by && sdev->quiesced_by != current);
2516
2517	if (sdev->quiesced_by == current)
2518		return 0;
2519
2520	blk_set_pm_only(q);
2521
2522	blk_mq_freeze_queue(q);
2523	/*
2524	 * Ensure that the effect of blk_set_pm_only() will be visible
2525	 * for percpu_ref_tryget() callers that occur after the queue
2526	 * unfreeze even if the queue was already frozen before this function
2527	 * was called. See also https://lwn.net/Articles/573497/.
2528	 */
2529	synchronize_rcu();
2530	blk_mq_unfreeze_queue(q);
2531
2532	mutex_lock(&sdev->state_mutex);
2533	err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2534	if (err == 0)
2535		sdev->quiesced_by = current;
2536	else
2537		blk_clear_pm_only(q);
2538	mutex_unlock(&sdev->state_mutex);
2539
2540	return err;
2541}
2542EXPORT_SYMBOL(scsi_device_quiesce);
2543
2544/**
2545 *	scsi_device_resume - Restart user issued commands to a quiesced device.
2546 *	@sdev:	scsi device to resume.
2547 *
2548 *	Moves the device from quiesced back to running and restarts the
2549 *	queues.
2550 *
2551 *	Must be called with user context, may sleep.
2552 */
2553void scsi_device_resume(struct scsi_device *sdev)
2554{
2555	/* check if the device state was mutated prior to resume, and if
2556	 * so assume the state is being managed elsewhere (for example
2557	 * device deleted during suspend)
2558	 */
2559	mutex_lock(&sdev->state_mutex);
2560	if (sdev->quiesced_by) {
2561		sdev->quiesced_by = NULL;
2562		blk_clear_pm_only(sdev->request_queue);
2563	}
2564	if (sdev->sdev_state == SDEV_QUIESCE)
2565		scsi_device_set_state(sdev, SDEV_RUNNING);
2566	mutex_unlock(&sdev->state_mutex);
2567}
2568EXPORT_SYMBOL(scsi_device_resume);
2569
2570static void
2571device_quiesce_fn(struct scsi_device *sdev, void *data)
2572{
2573	scsi_device_quiesce(sdev);
2574}
2575
2576void
2577scsi_target_quiesce(struct scsi_target *starget)
2578{
2579	starget_for_each_device(starget, NULL, device_quiesce_fn);
2580}
2581EXPORT_SYMBOL(scsi_target_quiesce);
2582
2583static void
2584device_resume_fn(struct scsi_device *sdev, void *data)
2585{
2586	scsi_device_resume(sdev);
2587}
2588
2589void
2590scsi_target_resume(struct scsi_target *starget)
2591{
2592	starget_for_each_device(starget, NULL, device_resume_fn);
2593}
2594EXPORT_SYMBOL(scsi_target_resume);
2595
2596/**
2597 * scsi_internal_device_block_nowait - try to transition to the SDEV_BLOCK state
2598 * @sdev: device to block
2599 *
2600 * Pause SCSI command processing on the specified device. Does not sleep.
 
 
2601 *
2602 * Returns zero if successful or a negative error code upon failure.
2603 *
2604 * Notes:
2605 * This routine transitions the device to the SDEV_BLOCK state (which must be
2606 * a legal transition). When the device is in this state, command processing
2607 * is paused until the device leaves the SDEV_BLOCK state. See also
2608 * scsi_internal_device_unblock_nowait().
2609 */
2610int scsi_internal_device_block_nowait(struct scsi_device *sdev)
 
2611{
2612	struct request_queue *q = sdev->request_queue;
 
2613	int err = 0;
2614
2615	err = scsi_device_set_state(sdev, SDEV_BLOCK);
2616	if (err) {
2617		err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2618
2619		if (err)
2620			return err;
2621	}
2622
2623	/*
2624	 * The device has transitioned to SDEV_BLOCK.  Stop the
2625	 * block layer from calling the midlayer with this device's
2626	 * request queue.
2627	 */
2628	blk_mq_quiesce_queue_nowait(q);
2629	return 0;
2630}
2631EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait);
2632
2633/**
2634 * scsi_internal_device_block - try to transition to the SDEV_BLOCK state
2635 * @sdev: device to block
2636 *
2637 * Pause SCSI command processing on the specified device and wait until all
2638 * ongoing scsi_request_fn() / scsi_queue_rq() calls have finished. May sleep.
2639 *
2640 * Returns zero if successful or a negative error code upon failure.
2641 *
2642 * Note:
2643 * This routine transitions the device to the SDEV_BLOCK state (which must be
2644 * a legal transition). When the device is in this state, command processing
2645 * is paused until the device leaves the SDEV_BLOCK state. See also
2646 * scsi_internal_device_unblock().
2647 */
2648static int scsi_internal_device_block(struct scsi_device *sdev)
2649{
2650	struct request_queue *q = sdev->request_queue;
2651	int err;
2652
2653	mutex_lock(&sdev->state_mutex);
2654	err = scsi_internal_device_block_nowait(sdev);
2655	if (err == 0)
2656		blk_mq_quiesce_queue(q);
2657	mutex_unlock(&sdev->state_mutex);
2658
2659	return err;
2660}
2661
2662void scsi_start_queue(struct scsi_device *sdev)
2663{
2664	struct request_queue *q = sdev->request_queue;
2665
2666	blk_mq_unquiesce_queue(q);
2667}
2668
 
2669/**
2670 * scsi_internal_device_unblock_nowait - resume a device after a block request
2671 * @sdev:	device to resume
2672 * @new_state:	state to set the device to after unblocking
2673 *
2674 * Restart the device queue for a previously suspended SCSI device. Does not
2675 * sleep.
2676 *
2677 * Returns zero if successful or a negative error code upon failure.
2678 *
2679 * Notes:
2680 * This routine transitions the device to the SDEV_RUNNING state or to one of
2681 * the offline states (which must be a legal transition) allowing the midlayer
2682 * to goose the queue for this device.
 
 
 
 
 
 
2683 */
2684int scsi_internal_device_unblock_nowait(struct scsi_device *sdev,
2685					enum scsi_device_state new_state)
 
2686{
2687	switch (new_state) {
2688	case SDEV_RUNNING:
2689	case SDEV_TRANSPORT_OFFLINE:
2690		break;
2691	default:
2692		return -EINVAL;
2693	}
2694
2695	/*
2696	 * Try to transition the scsi device to SDEV_RUNNING or one of the
2697	 * offlined states and goose the device queue if successful.
2698	 */
2699	switch (sdev->sdev_state) {
2700	case SDEV_BLOCK:
2701	case SDEV_TRANSPORT_OFFLINE:
2702		sdev->sdev_state = new_state;
2703		break;
2704	case SDEV_CREATED_BLOCK:
2705		if (new_state == SDEV_TRANSPORT_OFFLINE ||
2706		    new_state == SDEV_OFFLINE)
2707			sdev->sdev_state = new_state;
2708		else
2709			sdev->sdev_state = SDEV_CREATED;
2710		break;
2711	case SDEV_CANCEL:
2712	case SDEV_OFFLINE:
2713		break;
2714	default:
2715		return -EINVAL;
 
 
 
 
 
 
 
2716	}
2717	scsi_start_queue(sdev);
2718
2719	return 0;
2720}
2721EXPORT_SYMBOL_GPL(scsi_internal_device_unblock_nowait);
2722
2723/**
2724 * scsi_internal_device_unblock - resume a device after a block request
2725 * @sdev:	device to resume
2726 * @new_state:	state to set the device to after unblocking
2727 *
2728 * Restart the device queue for a previously suspended SCSI device. May sleep.
2729 *
2730 * Returns zero if successful or a negative error code upon failure.
2731 *
2732 * Notes:
2733 * This routine transitions the device to the SDEV_RUNNING state or to one of
2734 * the offline states (which must be a legal transition) allowing the midlayer
2735 * to goose the queue for this device.
2736 */
2737static int scsi_internal_device_unblock(struct scsi_device *sdev,
2738					enum scsi_device_state new_state)
2739{
2740	int ret;
2741
2742	mutex_lock(&sdev->state_mutex);
2743	ret = scsi_internal_device_unblock_nowait(sdev, new_state);
2744	mutex_unlock(&sdev->state_mutex);
2745
2746	return ret;
2747}
2748
2749static void
2750device_block(struct scsi_device *sdev, void *data)
2751{
2752	int ret;
2753
2754	ret = scsi_internal_device_block(sdev);
2755
2756	WARN_ONCE(ret, "scsi_internal_device_block(%s) failed: ret = %d\n",
2757		  dev_name(&sdev->sdev_gendev), ret);
2758}
2759
2760static int
2761target_block(struct device *dev, void *data)
2762{
2763	if (scsi_is_target_device(dev))
2764		starget_for_each_device(to_scsi_target(dev), NULL,
2765					device_block);
2766	return 0;
2767}
2768
2769void
2770scsi_target_block(struct device *dev)
2771{
2772	if (scsi_is_target_device(dev))
2773		starget_for_each_device(to_scsi_target(dev), NULL,
2774					device_block);
2775	else
2776		device_for_each_child(dev, NULL, target_block);
2777}
2778EXPORT_SYMBOL_GPL(scsi_target_block);
2779
2780static void
2781device_unblock(struct scsi_device *sdev, void *data)
2782{
2783	scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
2784}
2785
2786static int
2787target_unblock(struct device *dev, void *data)
2788{
2789	if (scsi_is_target_device(dev))
2790		starget_for_each_device(to_scsi_target(dev), data,
2791					device_unblock);
2792	return 0;
2793}
2794
2795void
2796scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
2797{
2798	if (scsi_is_target_device(dev))
2799		starget_for_each_device(to_scsi_target(dev), &new_state,
2800					device_unblock);
2801	else
2802		device_for_each_child(dev, &new_state, target_unblock);
2803}
2804EXPORT_SYMBOL_GPL(scsi_target_unblock);
2805
2806int
2807scsi_host_block(struct Scsi_Host *shost)
2808{
2809	struct scsi_device *sdev;
2810	int ret = 0;
2811
2812	/*
2813	 * Call scsi_internal_device_block_nowait so we can avoid
2814	 * calling synchronize_rcu() for each LUN.
2815	 */
2816	shost_for_each_device(sdev, shost) {
2817		mutex_lock(&sdev->state_mutex);
2818		ret = scsi_internal_device_block_nowait(sdev);
2819		mutex_unlock(&sdev->state_mutex);
2820		if (ret) {
2821			scsi_device_put(sdev);
2822			break;
2823		}
2824	}
2825
2826	/*
2827	 * SCSI never enables blk-mq's BLK_MQ_F_BLOCKING flag so
2828	 * calling synchronize_rcu() once is enough.
2829	 */
2830	WARN_ON_ONCE(shost->tag_set.flags & BLK_MQ_F_BLOCKING);
2831
2832	if (!ret)
2833		synchronize_rcu();
2834
2835	return ret;
2836}
2837EXPORT_SYMBOL_GPL(scsi_host_block);
2838
2839int
2840scsi_host_unblock(struct Scsi_Host *shost, int new_state)
2841{
2842	struct scsi_device *sdev;
2843	int ret = 0;
2844
2845	shost_for_each_device(sdev, shost) {
2846		ret = scsi_internal_device_unblock(sdev, new_state);
2847		if (ret) {
2848			scsi_device_put(sdev);
2849			break;
2850		}
2851	}
2852	return ret;
2853}
2854EXPORT_SYMBOL_GPL(scsi_host_unblock);
2855
2856/**
2857 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
2858 * @sgl:	scatter-gather list
2859 * @sg_count:	number of segments in sg
2860 * @offset:	offset in bytes into sg, on return offset into the mapped area
2861 * @len:	bytes to map, on return number of bytes mapped
2862 *
2863 * Returns virtual address of the start of the mapped page
2864 */
2865void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
2866			  size_t *offset, size_t *len)
2867{
2868	int i;
2869	size_t sg_len = 0, len_complete = 0;
2870	struct scatterlist *sg;
2871	struct page *page;
2872
2873	WARN_ON(!irqs_disabled());
2874
2875	for_each_sg(sgl, sg, sg_count, i) {
2876		len_complete = sg_len; /* Complete sg-entries */
2877		sg_len += sg->length;
2878		if (sg_len > *offset)
2879			break;
2880	}
2881
2882	if (unlikely(i == sg_count)) {
2883		printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
2884			"elements %d\n",
2885		       __func__, sg_len, *offset, sg_count);
2886		WARN_ON(1);
2887		return NULL;
2888	}
2889
2890	/* Offset starting from the beginning of first page in this sg-entry */
2891	*offset = *offset - len_complete + sg->offset;
2892
2893	/* Assumption: contiguous pages can be accessed as "page + i" */
2894	page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
2895	*offset &= ~PAGE_MASK;
2896
2897	/* Bytes in this sg-entry from *offset to the end of the page */
2898	sg_len = PAGE_SIZE - *offset;
2899	if (*len > sg_len)
2900		*len = sg_len;
2901
2902	return kmap_atomic(page);
2903}
2904EXPORT_SYMBOL(scsi_kmap_atomic_sg);
2905
2906/**
2907 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
2908 * @virt:	virtual address to be unmapped
2909 */
2910void scsi_kunmap_atomic_sg(void *virt)
2911{
2912	kunmap_atomic(virt);
2913}
2914EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
2915
2916void sdev_disable_disk_events(struct scsi_device *sdev)
2917{
2918	atomic_inc(&sdev->disk_events_disable_depth);
2919}
2920EXPORT_SYMBOL(sdev_disable_disk_events);
2921
2922void sdev_enable_disk_events(struct scsi_device *sdev)
2923{
2924	if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0))
2925		return;
2926	atomic_dec(&sdev->disk_events_disable_depth);
2927}
2928EXPORT_SYMBOL(sdev_enable_disk_events);
2929
2930/**
2931 * scsi_vpd_lun_id - return a unique device identification
2932 * @sdev: SCSI device
2933 * @id:   buffer for the identification
2934 * @id_len:  length of the buffer
2935 *
2936 * Copies a unique device identification into @id based
2937 * on the information in the VPD page 0x83 of the device.
2938 * The string will be formatted as a SCSI name string.
2939 *
2940 * Returns the length of the identification or error on failure.
2941 * If the identifier is longer than the supplied buffer the actual
2942 * identifier length is returned and the buffer is not zero-padded.
2943 */
2944int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len)
2945{
2946	u8 cur_id_type = 0xff;
2947	u8 cur_id_size = 0;
2948	const unsigned char *d, *cur_id_str;
2949	const struct scsi_vpd *vpd_pg83;
2950	int id_size = -EINVAL;
2951
2952	rcu_read_lock();
2953	vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
2954	if (!vpd_pg83) {
2955		rcu_read_unlock();
2956		return -ENXIO;
2957	}
2958
2959	/*
2960	 * Look for the correct descriptor.
2961	 * Order of preference for lun descriptor:
2962	 * - SCSI name string
2963	 * - NAA IEEE Registered Extended
2964	 * - EUI-64 based 16-byte
2965	 * - EUI-64 based 12-byte
2966	 * - NAA IEEE Registered
2967	 * - NAA IEEE Extended
2968	 * - T10 Vendor ID
2969	 * as longer descriptors reduce the likelyhood
2970	 * of identification clashes.
2971	 */
2972
2973	/* The id string must be at least 20 bytes + terminating NULL byte */
2974	if (id_len < 21) {
2975		rcu_read_unlock();
2976		return -EINVAL;
2977	}
2978
2979	memset(id, 0, id_len);
2980	d = vpd_pg83->data + 4;
2981	while (d < vpd_pg83->data + vpd_pg83->len) {
2982		/* Skip designators not referring to the LUN */
2983		if ((d[1] & 0x30) != 0x00)
2984			goto next_desig;
2985
2986		switch (d[1] & 0xf) {
2987		case 0x1:
2988			/* T10 Vendor ID */
2989			if (cur_id_size > d[3])
2990				break;
2991			/* Prefer anything */
2992			if (cur_id_type > 0x01 && cur_id_type != 0xff)
2993				break;
2994			cur_id_size = d[3];
2995			if (cur_id_size + 4 > id_len)
2996				cur_id_size = id_len - 4;
2997			cur_id_str = d + 4;
2998			cur_id_type = d[1] & 0xf;
2999			id_size = snprintf(id, id_len, "t10.%*pE",
3000					   cur_id_size, cur_id_str);
3001			break;
3002		case 0x2:
3003			/* EUI-64 */
3004			if (cur_id_size > d[3])
3005				break;
3006			/* Prefer NAA IEEE Registered Extended */
3007			if (cur_id_type == 0x3 &&
3008			    cur_id_size == d[3])
3009				break;
3010			cur_id_size = d[3];
3011			cur_id_str = d + 4;
3012			cur_id_type = d[1] & 0xf;
3013			switch (cur_id_size) {
3014			case 8:
3015				id_size = snprintf(id, id_len,
3016						   "eui.%8phN",
3017						   cur_id_str);
3018				break;
3019			case 12:
3020				id_size = snprintf(id, id_len,
3021						   "eui.%12phN",
3022						   cur_id_str);
3023				break;
3024			case 16:
3025				id_size = snprintf(id, id_len,
3026						   "eui.%16phN",
3027						   cur_id_str);
3028				break;
3029			default:
3030				cur_id_size = 0;
3031				break;
3032			}
3033			break;
3034		case 0x3:
3035			/* NAA */
3036			if (cur_id_size > d[3])
3037				break;
3038			cur_id_size = d[3];
3039			cur_id_str = d + 4;
3040			cur_id_type = d[1] & 0xf;
3041			switch (cur_id_size) {
3042			case 8:
3043				id_size = snprintf(id, id_len,
3044						   "naa.%8phN",
3045						   cur_id_str);
3046				break;
3047			case 16:
3048				id_size = snprintf(id, id_len,
3049						   "naa.%16phN",
3050						   cur_id_str);
3051				break;
3052			default:
3053				cur_id_size = 0;
3054				break;
3055			}
3056			break;
3057		case 0x8:
3058			/* SCSI name string */
3059			if (cur_id_size + 4 > d[3])
3060				break;
3061			/* Prefer others for truncated descriptor */
3062			if (cur_id_size && d[3] > id_len)
3063				break;
3064			cur_id_size = id_size = d[3];
3065			cur_id_str = d + 4;
3066			cur_id_type = d[1] & 0xf;
3067			if (cur_id_size >= id_len)
3068				cur_id_size = id_len - 1;
3069			memcpy(id, cur_id_str, cur_id_size);
3070			/* Decrease priority for truncated descriptor */
3071			if (cur_id_size != id_size)
3072				cur_id_size = 6;
3073			break;
3074		default:
3075			break;
3076		}
3077next_desig:
3078		d += d[3] + 4;
3079	}
3080	rcu_read_unlock();
3081
3082	return id_size;
3083}
3084EXPORT_SYMBOL(scsi_vpd_lun_id);
3085
3086/*
3087 * scsi_vpd_tpg_id - return a target port group identifier
3088 * @sdev: SCSI device
3089 *
3090 * Returns the Target Port Group identifier from the information
3091 * froom VPD page 0x83 of the device.
3092 *
3093 * Returns the identifier or error on failure.
3094 */
3095int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id)
3096{
3097	const unsigned char *d;
3098	const struct scsi_vpd *vpd_pg83;
3099	int group_id = -EAGAIN, rel_port = -1;
3100
3101	rcu_read_lock();
3102	vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3103	if (!vpd_pg83) {
3104		rcu_read_unlock();
3105		return -ENXIO;
3106	}
3107
3108	d = vpd_pg83->data + 4;
3109	while (d < vpd_pg83->data + vpd_pg83->len) {
3110		switch (d[1] & 0xf) {
3111		case 0x4:
3112			/* Relative target port */
3113			rel_port = get_unaligned_be16(&d[6]);
3114			break;
3115		case 0x5:
3116			/* Target port group */
3117			group_id = get_unaligned_be16(&d[6]);
3118			break;
3119		default:
3120			break;
3121		}
3122		d += d[3] + 4;
3123	}
3124	rcu_read_unlock();
3125
3126	if (group_id >= 0 && rel_id && rel_port != -1)
3127		*rel_id = rel_port;
3128
3129	return group_id;
3130}
3131EXPORT_SYMBOL(scsi_vpd_tpg_id);
v4.6
 
   1/*
   2 * Copyright (C) 1999 Eric Youngdale
   3 * Copyright (C) 2014 Christoph Hellwig
   4 *
   5 *  SCSI queueing library.
   6 *      Initial versions: Eric Youngdale (eric@andante.org).
   7 *                        Based upon conversations with large numbers
   8 *                        of people at Linux Expo.
   9 */
  10
  11#include <linux/bio.h>
  12#include <linux/bitops.h>
  13#include <linux/blkdev.h>
  14#include <linux/completion.h>
  15#include <linux/kernel.h>
  16#include <linux/export.h>
  17#include <linux/mempool.h>
  18#include <linux/slab.h>
  19#include <linux/init.h>
  20#include <linux/pci.h>
  21#include <linux/delay.h>
  22#include <linux/hardirq.h>
  23#include <linux/scatterlist.h>
  24#include <linux/blk-mq.h>
  25#include <linux/ratelimit.h>
  26#include <asm/unaligned.h>
  27
  28#include <scsi/scsi.h>
  29#include <scsi/scsi_cmnd.h>
  30#include <scsi/scsi_dbg.h>
  31#include <scsi/scsi_device.h>
  32#include <scsi/scsi_driver.h>
  33#include <scsi/scsi_eh.h>
  34#include <scsi/scsi_host.h>
 
  35#include <scsi/scsi_dh.h>
  36
  37#include <trace/events/scsi.h>
  38
 
  39#include "scsi_priv.h"
  40#include "scsi_logging.h"
  41
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  42
  43#define SG_MEMPOOL_NR		ARRAY_SIZE(scsi_sg_pools)
  44#define SG_MEMPOOL_SIZE		2
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  45
  46struct scsi_host_sg_pool {
  47	size_t		size;
  48	char		*name;
  49	struct kmem_cache	*slab;
  50	mempool_t	*pool;
  51};
  52
  53#define SP(x) { .size = x, "sgpool-" __stringify(x) }
  54#if (SCSI_MAX_SG_SEGMENTS < 32)
  55#error SCSI_MAX_SG_SEGMENTS is too small (must be 32 or greater)
  56#endif
  57static struct scsi_host_sg_pool scsi_sg_pools[] = {
  58	SP(8),
  59	SP(16),
  60#if (SCSI_MAX_SG_SEGMENTS > 32)
  61	SP(32),
  62#if (SCSI_MAX_SG_SEGMENTS > 64)
  63	SP(64),
  64#if (SCSI_MAX_SG_SEGMENTS > 128)
  65	SP(128),
  66#if (SCSI_MAX_SG_SEGMENTS > 256)
  67#error SCSI_MAX_SG_SEGMENTS is too large (256 MAX)
  68#endif
  69#endif
  70#endif
  71#endif
  72	SP(SCSI_MAX_SG_SEGMENTS)
  73};
  74#undef SP
  75
  76struct kmem_cache *scsi_sdb_cache;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  77
  78/*
  79 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
  80 * not change behaviour from the previous unplug mechanism, experimentation
  81 * may prove this needs changing.
  82 */
  83#define SCSI_QUEUE_DELAY	3
  84
  85static void
  86scsi_set_blocked(struct scsi_cmnd *cmd, int reason)
  87{
  88	struct Scsi_Host *host = cmd->device->host;
  89	struct scsi_device *device = cmd->device;
  90	struct scsi_target *starget = scsi_target(device);
  91
  92	/*
  93	 * Set the appropriate busy bit for the device/host.
  94	 *
  95	 * If the host/device isn't busy, assume that something actually
  96	 * completed, and that we should be able to queue a command now.
  97	 *
  98	 * Note that the prior mid-layer assumption that any host could
  99	 * always queue at least one command is now broken.  The mid-layer
 100	 * will implement a user specifiable stall (see
 101	 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
 102	 * if a command is requeued with no other commands outstanding
 103	 * either for the device or for the host.
 104	 */
 105	switch (reason) {
 106	case SCSI_MLQUEUE_HOST_BUSY:
 107		atomic_set(&host->host_blocked, host->max_host_blocked);
 108		break;
 109	case SCSI_MLQUEUE_DEVICE_BUSY:
 110	case SCSI_MLQUEUE_EH_RETRY:
 111		atomic_set(&device->device_blocked,
 112			   device->max_device_blocked);
 113		break;
 114	case SCSI_MLQUEUE_TARGET_BUSY:
 115		atomic_set(&starget->target_blocked,
 116			   starget->max_target_blocked);
 117		break;
 118	}
 119}
 120
 121static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd)
 122{
 123	struct scsi_device *sdev = cmd->device;
 124	struct request_queue *q = cmd->request->q;
 125
 126	blk_mq_requeue_request(cmd->request);
 127	blk_mq_kick_requeue_list(q);
 128	put_device(&sdev->sdev_gendev);
 
 129}
 130
 131/**
 132 * __scsi_queue_insert - private queue insertion
 133 * @cmd: The SCSI command being requeued
 134 * @reason:  The reason for the requeue
 135 * @unbusy: Whether the queue should be unbusied
 136 *
 137 * This is a private queue insertion.  The public interface
 138 * scsi_queue_insert() always assumes the queue should be unbusied
 139 * because it's always called before the completion.  This function is
 140 * for a requeue after completion, which should only occur in this
 141 * file.
 142 */
 143static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy)
 144{
 145	struct scsi_device *device = cmd->device;
 146	struct request_queue *q = device->request_queue;
 147	unsigned long flags;
 148
 149	SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd,
 150		"Inserting command %p into mlqueue\n", cmd));
 151
 152	scsi_set_blocked(cmd, reason);
 153
 154	/*
 155	 * Decrement the counters, since these commands are no longer
 156	 * active on the host/device.
 157	 */
 158	if (unbusy)
 159		scsi_device_unbusy(device);
 160
 161	/*
 162	 * Requeue this command.  It will go before all other commands
 163	 * that are already in the queue. Schedule requeue work under
 164	 * lock such that the kblockd_schedule_work() call happens
 165	 * before blk_cleanup_queue() finishes.
 166	 */
 167	cmd->result = 0;
 168	if (q->mq_ops) {
 169		scsi_mq_requeue_cmd(cmd);
 170		return;
 171	}
 172	spin_lock_irqsave(q->queue_lock, flags);
 173	blk_requeue_request(q, cmd->request);
 174	kblockd_schedule_work(&device->requeue_work);
 175	spin_unlock_irqrestore(q->queue_lock, flags);
 176}
 177
 178/*
 179 * Function:    scsi_queue_insert()
 180 *
 181 * Purpose:     Insert a command in the midlevel queue.
 182 *
 183 * Arguments:   cmd    - command that we are adding to queue.
 184 *              reason - why we are inserting command to queue.
 185 *
 186 * Lock status: Assumed that lock is not held upon entry.
 
 
 187 *
 188 * Returns:     Nothing.
 189 *
 190 * Notes:       We do this for one of two cases.  Either the host is busy
 191 *              and it cannot accept any more commands for the time being,
 192 *              or the device returned QUEUE_FULL and can accept no more
 193 *              commands.
 194 * Notes:       This could be called either from an interrupt context or a
 195 *              normal process context.
 196 */
 197void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
 198{
 199	__scsi_queue_insert(cmd, reason, 1);
 200}
 
 
 201/**
 202 * scsi_execute - insert request and wait for the result
 203 * @sdev:	scsi device
 204 * @cmd:	scsi command
 205 * @data_direction: data direction
 206 * @buffer:	data buffer
 207 * @bufflen:	len of buffer
 208 * @sense:	optional sense buffer
 
 209 * @timeout:	request timeout in seconds
 210 * @retries:	number of times to retry request
 211 * @flags:	or into request flags;
 
 212 * @resid:	optional residual length
 213 *
 214 * returns the req->errors value which is the scsi_cmnd result
 215 * field.
 216 */
 217int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
 218		 int data_direction, void *buffer, unsigned bufflen,
 219		 unsigned char *sense, int timeout, int retries, u64 flags,
 
 220		 int *resid)
 221{
 222	struct request *req;
 223	int write = (data_direction == DMA_TO_DEVICE);
 224	int ret = DRIVER_ERROR << 24;
 225
 226	req = blk_get_request(sdev->request_queue, write, __GFP_RECLAIM);
 
 
 227	if (IS_ERR(req))
 228		return ret;
 229	blk_rq_set_block_pc(req);
 230
 231	if (bufflen &&	blk_rq_map_kern(sdev->request_queue, req,
 232					buffer, bufflen, __GFP_RECLAIM))
 233		goto out;
 234
 235	req->cmd_len = COMMAND_SIZE(cmd[0]);
 236	memcpy(req->cmd, cmd, req->cmd_len);
 237	req->sense = sense;
 238	req->sense_len = 0;
 239	req->retries = retries;
 240	req->timeout = timeout;
 241	req->cmd_flags |= flags | REQ_QUIET | REQ_PREEMPT;
 
 242
 243	/*
 244	 * head injection *required* here otherwise quiesce won't work
 245	 */
 246	blk_execute_rq(req->q, NULL, req, 1);
 247
 248	/*
 249	 * Some devices (USB mass-storage in particular) may transfer
 250	 * garbage data together with a residue indicating that the data
 251	 * is invalid.  Prevent the garbage from being misinterpreted
 252	 * and prevent security leaks by zeroing out the excess data.
 253	 */
 254	if (unlikely(req->resid_len > 0 && req->resid_len <= bufflen))
 255		memset(buffer + (bufflen - req->resid_len), 0, req->resid_len);
 256
 257	if (resid)
 258		*resid = req->resid_len;
 259	ret = req->errors;
 
 
 
 
 260 out:
 261	blk_put_request(req);
 262
 263	return ret;
 264}
 265EXPORT_SYMBOL(scsi_execute);
 266
 267int scsi_execute_req_flags(struct scsi_device *sdev, const unsigned char *cmd,
 268		     int data_direction, void *buffer, unsigned bufflen,
 269		     struct scsi_sense_hdr *sshdr, int timeout, int retries,
 270		     int *resid, u64 flags)
 271{
 272	char *sense = NULL;
 273	int result;
 274	
 275	if (sshdr) {
 276		sense = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO);
 277		if (!sense)
 278			return DRIVER_ERROR << 24;
 279	}
 280	result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen,
 281			      sense, timeout, retries, flags, resid);
 282	if (sshdr)
 283		scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr);
 284
 285	kfree(sense);
 286	return result;
 287}
 288EXPORT_SYMBOL(scsi_execute_req_flags);
 289
 290/*
 291 * Function:    scsi_init_cmd_errh()
 292 *
 293 * Purpose:     Initialize cmd fields related to error handling.
 294 *
 295 * Arguments:   cmd	- command that is ready to be queued.
 296 *
 297 * Notes:       This function has the job of initializing a number of
 298 *              fields related to error handling.   Typically this will
 299 *              be called once for each command, as required.
 300 */
 301static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
 302{
 303	cmd->serial_number = 0;
 304	scsi_set_resid(cmd, 0);
 305	memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
 306	if (cmd->cmd_len == 0)
 307		cmd->cmd_len = scsi_command_size(cmd->cmnd);
 308}
 309
 310void scsi_device_unbusy(struct scsi_device *sdev)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 311{
 312	struct Scsi_Host *shost = sdev->host;
 313	struct scsi_target *starget = scsi_target(sdev);
 314	unsigned long flags;
 315
 316	atomic_dec(&shost->host_busy);
 
 317	if (starget->can_queue > 0)
 318		atomic_dec(&starget->target_busy);
 319
 320	if (unlikely(scsi_host_in_recovery(shost) &&
 321		     (shost->host_failed || shost->host_eh_scheduled))) {
 322		spin_lock_irqsave(shost->host_lock, flags);
 323		scsi_eh_wakeup(shost);
 324		spin_unlock_irqrestore(shost->host_lock, flags);
 325	}
 326
 327	atomic_dec(&sdev->device_busy);
 328}
 329
 330static void scsi_kick_queue(struct request_queue *q)
 331{
 332	if (q->mq_ops)
 333		blk_mq_start_hw_queues(q);
 334	else
 335		blk_run_queue(q);
 336}
 337
 338/*
 339 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
 340 * and call blk_run_queue for all the scsi_devices on the target -
 341 * including current_sdev first.
 342 *
 343 * Called with *no* scsi locks held.
 344 */
 345static void scsi_single_lun_run(struct scsi_device *current_sdev)
 346{
 347	struct Scsi_Host *shost = current_sdev->host;
 348	struct scsi_device *sdev, *tmp;
 349	struct scsi_target *starget = scsi_target(current_sdev);
 350	unsigned long flags;
 351
 352	spin_lock_irqsave(shost->host_lock, flags);
 353	starget->starget_sdev_user = NULL;
 354	spin_unlock_irqrestore(shost->host_lock, flags);
 355
 356	/*
 357	 * Call blk_run_queue for all LUNs on the target, starting with
 358	 * current_sdev. We race with others (to set starget_sdev_user),
 359	 * but in most cases, we will be first. Ideally, each LU on the
 360	 * target would get some limited time or requests on the target.
 361	 */
 362	scsi_kick_queue(current_sdev->request_queue);
 363
 364	spin_lock_irqsave(shost->host_lock, flags);
 365	if (starget->starget_sdev_user)
 366		goto out;
 367	list_for_each_entry_safe(sdev, tmp, &starget->devices,
 368			same_target_siblings) {
 369		if (sdev == current_sdev)
 370			continue;
 371		if (scsi_device_get(sdev))
 372			continue;
 373
 374		spin_unlock_irqrestore(shost->host_lock, flags);
 375		scsi_kick_queue(sdev->request_queue);
 376		spin_lock_irqsave(shost->host_lock, flags);
 377	
 378		scsi_device_put(sdev);
 379	}
 380 out:
 381	spin_unlock_irqrestore(shost->host_lock, flags);
 382}
 383
 384static inline bool scsi_device_is_busy(struct scsi_device *sdev)
 385{
 386	if (atomic_read(&sdev->device_busy) >= sdev->queue_depth)
 387		return true;
 388	if (atomic_read(&sdev->device_blocked) > 0)
 389		return true;
 390	return false;
 391}
 392
 393static inline bool scsi_target_is_busy(struct scsi_target *starget)
 394{
 395	if (starget->can_queue > 0) {
 396		if (atomic_read(&starget->target_busy) >= starget->can_queue)
 397			return true;
 398		if (atomic_read(&starget->target_blocked) > 0)
 399			return true;
 400	}
 401	return false;
 402}
 403
 404static inline bool scsi_host_is_busy(struct Scsi_Host *shost)
 405{
 406	if (shost->can_queue > 0 &&
 407	    atomic_read(&shost->host_busy) >= shost->can_queue)
 408		return true;
 409	if (atomic_read(&shost->host_blocked) > 0)
 410		return true;
 411	if (shost->host_self_blocked)
 412		return true;
 413	return false;
 414}
 415
 416static void scsi_starved_list_run(struct Scsi_Host *shost)
 417{
 418	LIST_HEAD(starved_list);
 419	struct scsi_device *sdev;
 420	unsigned long flags;
 421
 422	spin_lock_irqsave(shost->host_lock, flags);
 423	list_splice_init(&shost->starved_list, &starved_list);
 424
 425	while (!list_empty(&starved_list)) {
 426		struct request_queue *slq;
 427
 428		/*
 429		 * As long as shost is accepting commands and we have
 430		 * starved queues, call blk_run_queue. scsi_request_fn
 431		 * drops the queue_lock and can add us back to the
 432		 * starved_list.
 433		 *
 434		 * host_lock protects the starved_list and starved_entry.
 435		 * scsi_request_fn must get the host_lock before checking
 436		 * or modifying starved_list or starved_entry.
 437		 */
 438		if (scsi_host_is_busy(shost))
 439			break;
 440
 441		sdev = list_entry(starved_list.next,
 442				  struct scsi_device, starved_entry);
 443		list_del_init(&sdev->starved_entry);
 444		if (scsi_target_is_busy(scsi_target(sdev))) {
 445			list_move_tail(&sdev->starved_entry,
 446				       &shost->starved_list);
 447			continue;
 448		}
 449
 450		/*
 451		 * Once we drop the host lock, a racing scsi_remove_device()
 452		 * call may remove the sdev from the starved list and destroy
 453		 * it and the queue.  Mitigate by taking a reference to the
 454		 * queue and never touching the sdev again after we drop the
 455		 * host lock.  Note: if __scsi_remove_device() invokes
 456		 * blk_cleanup_queue() before the queue is run from this
 457		 * function then blk_run_queue() will return immediately since
 458		 * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING.
 459		 */
 460		slq = sdev->request_queue;
 461		if (!blk_get_queue(slq))
 462			continue;
 463		spin_unlock_irqrestore(shost->host_lock, flags);
 464
 465		scsi_kick_queue(slq);
 466		blk_put_queue(slq);
 467
 468		spin_lock_irqsave(shost->host_lock, flags);
 469	}
 470	/* put any unprocessed entries back */
 471	list_splice(&starved_list, &shost->starved_list);
 472	spin_unlock_irqrestore(shost->host_lock, flags);
 473}
 474
 475/*
 476 * Function:   scsi_run_queue()
 477 *
 478 * Purpose:    Select a proper request queue to serve next
 479 *
 480 * Arguments:  q       - last request's queue
 481 *
 482 * Returns:     Nothing
 483 *
 484 * Notes:      The previous command was completely finished, start
 485 *             a new one if possible.
 486 */
 487static void scsi_run_queue(struct request_queue *q)
 488{
 489	struct scsi_device *sdev = q->queuedata;
 490
 491	if (scsi_target(sdev)->single_lun)
 492		scsi_single_lun_run(sdev);
 493	if (!list_empty(&sdev->host->starved_list))
 494		scsi_starved_list_run(sdev->host);
 495
 496	if (q->mq_ops)
 497		blk_mq_start_stopped_hw_queues(q, false);
 498	else
 499		blk_run_queue(q);
 500}
 501
 502void scsi_requeue_run_queue(struct work_struct *work)
 503{
 504	struct scsi_device *sdev;
 505	struct request_queue *q;
 506
 507	sdev = container_of(work, struct scsi_device, requeue_work);
 508	q = sdev->request_queue;
 509	scsi_run_queue(q);
 510}
 511
 512/*
 513 * Function:	scsi_requeue_command()
 514 *
 515 * Purpose:	Handle post-processing of completed commands.
 516 *
 517 * Arguments:	q	- queue to operate on
 518 *		cmd	- command that may need to be requeued.
 519 *
 520 * Returns:	Nothing
 521 *
 522 * Notes:	After command completion, there may be blocks left
 523 *		over which weren't finished by the previous command
 524 *		this can be for a number of reasons - the main one is
 525 *		I/O errors in the middle of the request, in which case
 526 *		we need to request the blocks that come after the bad
 527 *		sector.
 528 * Notes:	Upon return, cmd is a stale pointer.
 529 */
 530static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd)
 531{
 532	struct scsi_device *sdev = cmd->device;
 533	struct request *req = cmd->request;
 534	unsigned long flags;
 535
 536	spin_lock_irqsave(q->queue_lock, flags);
 537	blk_unprep_request(req);
 538	req->special = NULL;
 539	scsi_put_command(cmd);
 540	blk_requeue_request(q, req);
 541	spin_unlock_irqrestore(q->queue_lock, flags);
 542
 543	scsi_run_queue(q);
 544
 545	put_device(&sdev->sdev_gendev);
 546}
 547
 548void scsi_run_host_queues(struct Scsi_Host *shost)
 549{
 550	struct scsi_device *sdev;
 551
 552	shost_for_each_device(sdev, shost)
 553		scsi_run_queue(sdev->request_queue);
 554}
 555
 556static inline unsigned int scsi_sgtable_index(unsigned short nents)
 557{
 558	unsigned int index;
 559
 560	BUG_ON(nents > SCSI_MAX_SG_SEGMENTS);
 561
 562	if (nents <= 8)
 563		index = 0;
 564	else
 565		index = get_count_order(nents) - 3;
 566
 567	return index;
 568}
 569
 570static void scsi_sg_free(struct scatterlist *sgl, unsigned int nents)
 571{
 572	struct scsi_host_sg_pool *sgp;
 573
 574	sgp = scsi_sg_pools + scsi_sgtable_index(nents);
 575	mempool_free(sgl, sgp->pool);
 576}
 577
 578static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask)
 579{
 580	struct scsi_host_sg_pool *sgp;
 581
 582	sgp = scsi_sg_pools + scsi_sgtable_index(nents);
 583	return mempool_alloc(sgp->pool, gfp_mask);
 584}
 585
 586static void scsi_free_sgtable(struct scsi_data_buffer *sdb, bool mq)
 587{
 588	if (mq && sdb->table.orig_nents <= SCSI_MAX_SG_SEGMENTS)
 589		return;
 590	__sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, mq, scsi_sg_free);
 591}
 592
 593static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents, bool mq)
 594{
 595	struct scatterlist *first_chunk = NULL;
 596	int ret;
 597
 598	BUG_ON(!nents);
 599
 600	if (mq) {
 601		if (nents <= SCSI_MAX_SG_SEGMENTS) {
 602			sdb->table.nents = sdb->table.orig_nents = nents;
 603			sg_init_table(sdb->table.sgl, nents);
 604			return 0;
 605		}
 606		first_chunk = sdb->table.sgl;
 607	}
 608
 609	ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS,
 610			       first_chunk, GFP_ATOMIC, scsi_sg_alloc);
 611	if (unlikely(ret))
 612		scsi_free_sgtable(sdb, mq);
 613	return ret;
 614}
 615
 616static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
 617{
 618	if (cmd->request->cmd_type == REQ_TYPE_FS) {
 619		struct scsi_driver *drv = scsi_cmd_to_driver(cmd);
 620
 621		if (drv->uninit_command)
 622			drv->uninit_command(cmd);
 623	}
 624}
 625
 626static void scsi_mq_free_sgtables(struct scsi_cmnd *cmd)
 627{
 628	if (cmd->sdb.table.nents)
 629		scsi_free_sgtable(&cmd->sdb, true);
 630	if (cmd->request->next_rq && cmd->request->next_rq->special)
 631		scsi_free_sgtable(cmd->request->next_rq->special, true);
 632	if (scsi_prot_sg_count(cmd))
 633		scsi_free_sgtable(cmd->prot_sdb, true);
 
 634}
 635
 636static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
 637{
 638	struct scsi_device *sdev = cmd->device;
 639	struct Scsi_Host *shost = sdev->host;
 640	unsigned long flags;
 641
 642	scsi_mq_free_sgtables(cmd);
 643	scsi_uninit_cmd(cmd);
 644
 645	if (shost->use_cmd_list) {
 646		BUG_ON(list_empty(&cmd->list));
 647		spin_lock_irqsave(&sdev->list_lock, flags);
 648		list_del_init(&cmd->list);
 649		spin_unlock_irqrestore(&sdev->list_lock, flags);
 650	}
 651}
 652
 653/*
 654 * Function:    scsi_release_buffers()
 655 *
 656 * Purpose:     Free resources allocate for a scsi_command.
 657 *
 658 * Arguments:   cmd	- command that we are bailing.
 659 *
 660 * Lock status: Assumed that no lock is held upon entry.
 661 *
 662 * Returns:     Nothing
 663 *
 664 * Notes:       In the event that an upper level driver rejects a
 665 *		command, we must release resources allocated during
 666 *		the __init_io() function.  Primarily this would involve
 667 *		the scatter-gather table.
 668 */
 669static void scsi_release_buffers(struct scsi_cmnd *cmd)
 670{
 671	if (cmd->sdb.table.nents)
 672		scsi_free_sgtable(&cmd->sdb, false);
 673
 674	memset(&cmd->sdb, 0, sizeof(cmd->sdb));
 675
 676	if (scsi_prot_sg_count(cmd))
 677		scsi_free_sgtable(cmd->prot_sdb, false);
 678}
 679
 680static void scsi_release_bidi_buffers(struct scsi_cmnd *cmd)
 
 
 681{
 682	struct scsi_data_buffer *bidi_sdb = cmd->request->next_rq->special;
 683
 684	scsi_free_sgtable(bidi_sdb, false);
 685	kmem_cache_free(scsi_sdb_cache, bidi_sdb);
 686	cmd->request->next_rq->special = NULL;
 687}
 688
 689static bool scsi_end_request(struct request *req, int error,
 690		unsigned int bytes, unsigned int bidi_bytes)
 691{
 692	struct scsi_cmnd *cmd = req->special;
 693	struct scsi_device *sdev = cmd->device;
 694	struct request_queue *q = sdev->request_queue;
 695
 696	if (blk_update_request(req, error, bytes))
 697		return true;
 698
 699	/* Bidi request must be completed as a whole */
 700	if (unlikely(bidi_bytes) &&
 701	    blk_update_request(req->next_rq, error, bidi_bytes))
 702		return true;
 703
 704	if (blk_queue_add_random(q))
 705		add_disk_randomness(req->rq_disk);
 706
 707	if (req->mq_ctx) {
 708		/*
 709		 * In the MQ case the command gets freed by __blk_mq_end_request,
 710		 * so we have to do all cleanup that depends on it earlier.
 711		 *
 712		 * We also can't kick the queues from irq context, so we
 713		 * will have to defer it to a workqueue.
 714		 */
 715		scsi_mq_uninit_cmd(cmd);
 716
 717		__blk_mq_end_request(req, error);
 
 
 
 
 
 
 718
 719		if (scsi_target(sdev)->single_lun ||
 720		    !list_empty(&sdev->host->starved_list))
 721			kblockd_schedule_work(&sdev->requeue_work);
 722		else
 723			blk_mq_start_stopped_hw_queues(q, true);
 724	} else {
 725		unsigned long flags;
 
 726
 727		if (bidi_bytes)
 728			scsi_release_bidi_buffers(cmd);
 729
 730		spin_lock_irqsave(q->queue_lock, flags);
 731		blk_finish_request(req, error);
 732		spin_unlock_irqrestore(q->queue_lock, flags);
 733
 734		scsi_release_buffers(cmd);
 735
 736		scsi_put_command(cmd);
 737		scsi_run_queue(q);
 738	}
 739
 740	put_device(&sdev->sdev_gendev);
 741	return false;
 742}
 743
 744/**
 745 * __scsi_error_from_host_byte - translate SCSI error code into errno
 746 * @cmd:	SCSI command (unused)
 747 * @result:	scsi error code
 748 *
 749 * Translate SCSI error code into standard UNIX errno.
 750 * Return values:
 751 * -ENOLINK	temporary transport failure
 752 * -EREMOTEIO	permanent target failure, do not retry
 753 * -EBADE	permanent nexus failure, retry on other path
 754 * -ENOSPC	No write space available
 755 * -ENODATA	Medium error
 756 * -EIO		unspecified I/O error
 757 */
 758static int __scsi_error_from_host_byte(struct scsi_cmnd *cmd, int result)
 759{
 760	int error = 0;
 761
 762	switch(host_byte(result)) {
 
 
 
 
 
 
 
 763	case DID_TRANSPORT_FAILFAST:
 764		error = -ENOLINK;
 765		break;
 766	case DID_TARGET_FAILURE:
 767		set_host_byte(cmd, DID_OK);
 768		error = -EREMOTEIO;
 769		break;
 770	case DID_NEXUS_FAILURE:
 771		set_host_byte(cmd, DID_OK);
 772		error = -EBADE;
 773		break;
 774	case DID_ALLOC_FAILURE:
 775		set_host_byte(cmd, DID_OK);
 776		error = -ENOSPC;
 777		break;
 778	case DID_MEDIUM_ERROR:
 779		set_host_byte(cmd, DID_OK);
 780		error = -ENODATA;
 781		break;
 782	default:
 783		error = -EIO;
 784		break;
 785	}
 
 786
 787	return error;
 
 
 
 
 
 788}
 789
 790/*
 791 * Function:    scsi_io_completion()
 792 *
 793 * Purpose:     Completion processing for block device I/O requests.
 794 *
 795 * Arguments:   cmd   - command that is finished.
 796 *
 797 * Lock status: Assumed that no lock is held upon entry.
 798 *
 799 * Returns:     Nothing
 800 *
 801 * Notes:       We will finish off the specified number of sectors.  If we
 802 *		are done, the command block will be released and the queue
 803 *		function will be goosed.  If we are not done then we have to
 804 *		figure out what to do next:
 805 *
 806 *		a) We can call scsi_requeue_command().  The request
 807 *		   will be unprepared and put back on the queue.  Then
 808 *		   a new command will be created for it.  This should
 809 *		   be used if we made forward progress, or if we want
 810 *		   to switch from READ(10) to READ(6) for example.
 811 *
 812 *		b) We can call __scsi_queue_insert().  The request will
 813 *		   be put back on the queue and retried using the same
 814 *		   command as before, possibly after a delay.
 815 *
 816 *		c) We can call scsi_end_request() with -EIO to fail
 817 *		   the remainder of the request.
 818 */
 819void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
 820{
 821	int result = cmd->result;
 822	struct request_queue *q = cmd->device->request_queue;
 823	struct request *req = cmd->request;
 824	int error = 0;
 825	struct scsi_sense_hdr sshdr;
 826	bool sense_valid = false;
 827	int sense_deferred = 0, level = 0;
 828	enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,
 829	      ACTION_DELAYED_RETRY} action;
 830	unsigned long wait_for = (cmd->allowed + 1) * req->timeout;
 
 
 
 
 
 
 
 
 831
 832	if (result) {
 833		sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
 834		if (sense_valid)
 835			sense_deferred = scsi_sense_is_deferred(&sshdr);
 836	}
 837
 838	if (req->cmd_type == REQ_TYPE_BLOCK_PC) { /* SG_IO ioctl from block level */
 839		if (result) {
 840			if (sense_valid && req->sense) {
 841				/*
 842				 * SG_IO wants current and deferred errors
 843				 */
 844				int len = 8 + cmd->sense_buffer[7];
 845
 846				if (len > SCSI_SENSE_BUFFERSIZE)
 847					len = SCSI_SENSE_BUFFERSIZE;
 848				memcpy(req->sense, cmd->sense_buffer,  len);
 849				req->sense_len = len;
 850			}
 851			if (!sense_deferred)
 852				error = __scsi_error_from_host_byte(cmd, result);
 853		}
 854		/*
 855		 * __scsi_error_from_host_byte may have reset the host_byte
 856		 */
 857		req->errors = cmd->result;
 858
 859		req->resid_len = scsi_get_resid(cmd);
 860
 861		if (scsi_bidi_cmnd(cmd)) {
 862			/*
 863			 * Bidi commands Must be complete as a whole,
 864			 * both sides at once.
 865			 */
 866			req->next_rq->resid_len = scsi_in(cmd)->resid;
 867			if (scsi_end_request(req, 0, blk_rq_bytes(req),
 868					blk_rq_bytes(req->next_rq)))
 869				BUG();
 870			return;
 871		}
 872	} else if (blk_rq_bytes(req) == 0 && result && !sense_deferred) {
 873		/*
 874		 * Certain non BLOCK_PC requests are commands that don't
 875		 * actually transfer anything (FLUSH), so cannot use
 876		 * good_bytes != blk_rq_bytes(req) as the signal for an error.
 877		 * This sets the error explicitly for the problem case.
 878		 */
 879		error = __scsi_error_from_host_byte(cmd, result);
 880	}
 881
 882	/* no bidi support for !REQ_TYPE_BLOCK_PC yet */
 883	BUG_ON(blk_bidi_rq(req));
 884
 885	/*
 886	 * Next deal with any sectors which we were able to correctly
 887	 * handle.
 888	 */
 889	SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd,
 890		"%u sectors total, %d bytes done.\n",
 891		blk_rq_sectors(req), good_bytes));
 892
 893	/*
 894	 * Recovered errors need reporting, but they're always treated
 895	 * as success, so fiddle the result code here.  For BLOCK_PC
 896	 * we already took a copy of the original into rq->errors which
 897	 * is what gets returned to the user
 898	 */
 899	if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
 900		/* if ATA PASS-THROUGH INFORMATION AVAILABLE skip
 901		 * print since caller wants ATA registers. Only occurs on
 902		 * SCSI ATA PASS_THROUGH commands when CK_COND=1
 903		 */
 904		if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
 905			;
 906		else if (!(req->cmd_flags & REQ_QUIET))
 907			scsi_print_sense(cmd);
 908		result = 0;
 909		/* BLOCK_PC may have set error */
 910		error = 0;
 911	}
 912
 913	/*
 914	 * If we finished all bytes in the request we are done now.
 915	 */
 916	if (!scsi_end_request(req, error, good_bytes, 0))
 917		return;
 918
 919	/*
 920	 * Kill remainder if no retrys.
 921	 */
 922	if (error && scsi_noretry_cmd(cmd)) {
 923		if (scsi_end_request(req, error, blk_rq_bytes(req), 0))
 924			BUG();
 925		return;
 926	}
 927
 928	/*
 929	 * If there had been no error, but we have leftover bytes in the
 930	 * requeues just queue the command up again.
 931	 */
 932	if (result == 0)
 933		goto requeue;
 934
 935	error = __scsi_error_from_host_byte(cmd, result);
 936
 937	if (host_byte(result) == DID_RESET) {
 938		/* Third party bus reset or reset for error recovery
 939		 * reasons.  Just retry the command and see what
 940		 * happens.
 941		 */
 942		action = ACTION_RETRY;
 943	} else if (sense_valid && !sense_deferred) {
 944		switch (sshdr.sense_key) {
 945		case UNIT_ATTENTION:
 946			if (cmd->device->removable) {
 947				/* Detected disc change.  Set a bit
 948				 * and quietly refuse further access.
 949				 */
 950				cmd->device->changed = 1;
 951				action = ACTION_FAIL;
 952			} else {
 953				/* Must have been a power glitch, or a
 954				 * bus reset.  Could not have been a
 955				 * media change, so we just retry the
 956				 * command and see what happens.
 957				 */
 958				action = ACTION_RETRY;
 959			}
 960			break;
 961		case ILLEGAL_REQUEST:
 962			/* If we had an ILLEGAL REQUEST returned, then
 963			 * we may have performed an unsupported
 964			 * command.  The only thing this should be
 965			 * would be a ten byte read where only a six
 966			 * byte read was supported.  Also, on a system
 967			 * where READ CAPACITY failed, we may have
 968			 * read past the end of the disk.
 969			 */
 970			if ((cmd->device->use_10_for_rw &&
 971			    sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
 972			    (cmd->cmnd[0] == READ_10 ||
 973			     cmd->cmnd[0] == WRITE_10)) {
 974				/* This will issue a new 6-byte command. */
 975				cmd->device->use_10_for_rw = 0;
 976				action = ACTION_REPREP;
 977			} else if (sshdr.asc == 0x10) /* DIX */ {
 978				action = ACTION_FAIL;
 979				error = -EILSEQ;
 980			/* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
 981			} else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
 982				action = ACTION_FAIL;
 983				error = -EREMOTEIO;
 984			} else
 985				action = ACTION_FAIL;
 986			break;
 987		case ABORTED_COMMAND:
 988			action = ACTION_FAIL;
 989			if (sshdr.asc == 0x10) /* DIF */
 990				error = -EILSEQ;
 991			break;
 992		case NOT_READY:
 993			/* If the device is in the process of becoming
 994			 * ready, or has a temporary blockage, retry.
 995			 */
 996			if (sshdr.asc == 0x04) {
 997				switch (sshdr.ascq) {
 998				case 0x01: /* becoming ready */
 999				case 0x04: /* format in progress */
1000				case 0x05: /* rebuild in progress */
1001				case 0x06: /* recalculation in progress */
1002				case 0x07: /* operation in progress */
1003				case 0x08: /* Long write in progress */
1004				case 0x09: /* self test in progress */
1005				case 0x14: /* space allocation in progress */
 
 
 
 
1006					action = ACTION_DELAYED_RETRY;
1007					break;
1008				default:
1009					action = ACTION_FAIL;
1010					break;
1011				}
1012			} else
1013				action = ACTION_FAIL;
1014			break;
1015		case VOLUME_OVERFLOW:
1016			/* See SSC3rXX or current. */
1017			action = ACTION_FAIL;
1018			break;
1019		default:
1020			action = ACTION_FAIL;
1021			break;
1022		}
1023	} else
1024		action = ACTION_FAIL;
1025
1026	if (action != ACTION_FAIL &&
1027	    time_before(cmd->jiffies_at_alloc + wait_for, jiffies))
1028		action = ACTION_FAIL;
1029
1030	switch (action) {
1031	case ACTION_FAIL:
1032		/* Give up and fail the remainder of the request */
1033		if (!(req->cmd_flags & REQ_QUIET)) {
1034			static DEFINE_RATELIMIT_STATE(_rs,
1035					DEFAULT_RATELIMIT_INTERVAL,
1036					DEFAULT_RATELIMIT_BURST);
1037
1038			if (unlikely(scsi_logging_level))
1039				level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
1040						       SCSI_LOG_MLCOMPLETE_BITS);
 
1041
1042			/*
1043			 * if logging is enabled the failure will be printed
1044			 * in scsi_log_completion(), so avoid duplicate messages
1045			 */
1046			if (!level && __ratelimit(&_rs)) {
1047				scsi_print_result(cmd, NULL, FAILED);
1048				if (driver_byte(result) & DRIVER_SENSE)
1049					scsi_print_sense(cmd);
1050				scsi_print_command(cmd);
1051			}
1052		}
1053		if (!scsi_end_request(req, error, blk_rq_err_bytes(req), 0))
1054			return;
1055		/*FALLTHRU*/
1056	case ACTION_REPREP:
1057	requeue:
1058		/* Unprep the request and put it back at the head of the queue.
1059		 * A new command will be prepared and issued.
1060		 */
1061		if (q->mq_ops) {
1062			cmd->request->cmd_flags &= ~REQ_DONTPREP;
1063			scsi_mq_uninit_cmd(cmd);
1064			scsi_mq_requeue_cmd(cmd);
1065		} else {
1066			scsi_release_buffers(cmd);
1067			scsi_requeue_command(q, cmd);
1068		}
1069		break;
1070	case ACTION_RETRY:
1071		/* Retry the same command immediately */
1072		__scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, 0);
1073		break;
1074	case ACTION_DELAYED_RETRY:
1075		/* Retry the same command after a delay */
1076		__scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, 0);
1077		break;
1078	}
1079}
1080
1081static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb)
 
 
 
 
 
 
1082{
1083	int count;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1084
1085	/*
1086	 * If sg table allocation fails, requeue request later.
 
1087	 */
1088	if (unlikely(scsi_alloc_sgtable(sdb, req->nr_phys_segments,
1089					req->mq_ctx != NULL)))
1090		return BLKPREP_DEFER;
 
 
 
 
 
 
 
 
 
1091
1092	/* 
1093	 * Next, walk the list, and fill in the addresses and sizes of
1094	 * each segment.
1095	 */
1096	count = blk_rq_map_sg(req->q, req, sdb->table.sgl);
1097	BUG_ON(count > sdb->table.nents);
1098	sdb->table.nents = count;
1099	sdb->length = blk_rq_bytes(req);
1100	return BLKPREP_OK;
1101}
1102
1103/*
1104 * Function:    scsi_init_io()
1105 *
1106 * Purpose:     SCSI I/O initialize function.
 
 
 
 
 
 
 
1107 *
1108 * Arguments:   cmd   - Command descriptor we wish to initialize
1109 *
1110 * Returns:     0 on success
1111 *		BLKPREP_DEFER if the failure is retryable
1112 *		BLKPREP_KILL if the failure is fatal
1113 */
1114int scsi_init_io(struct scsi_cmnd *cmd)
1115{
1116	struct scsi_device *sdev = cmd->device;
1117	struct request *rq = cmd->request;
1118	bool is_mq = (rq->mq_ctx != NULL);
1119	int error;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1120
1121	BUG_ON(!rq->nr_phys_segments);
 
 
1122
1123	error = scsi_init_sgtable(rq, &cmd->sdb);
1124	if (error)
1125		goto err_exit;
1126
1127	if (blk_bidi_rq(rq)) {
1128		if (!rq->q->mq_ops) {
1129			struct scsi_data_buffer *bidi_sdb =
1130				kmem_cache_zalloc(scsi_sdb_cache, GFP_ATOMIC);
1131			if (!bidi_sdb) {
1132				error = BLKPREP_DEFER;
1133				goto err_exit;
1134			}
1135
1136			rq->next_rq->special = bidi_sdb;
1137		}
 
 
 
1138
1139		error = scsi_init_sgtable(rq->next_rq, rq->next_rq->special);
1140		if (error)
1141			goto err_exit;
1142	}
1143
 
 
 
 
1144	if (blk_integrity_rq(rq)) {
1145		struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1146		int ivecs, count;
1147
1148		if (prot_sdb == NULL) {
1149			/*
1150			 * This can happen if someone (e.g. multipath)
1151			 * queues a command to a device on an adapter
1152			 * that does not support DIX.
1153			 */
1154			WARN_ON_ONCE(1);
1155			error = BLKPREP_KILL;
1156			goto err_exit;
1157		}
1158
1159		ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
1160
1161		if (scsi_alloc_sgtable(prot_sdb, ivecs, is_mq)) {
1162			error = BLKPREP_DEFER;
1163			goto err_exit;
 
 
1164		}
1165
1166		count = blk_rq_map_integrity_sg(rq->q, rq->bio,
1167						prot_sdb->table.sgl);
1168		BUG_ON(unlikely(count > ivecs));
1169		BUG_ON(unlikely(count > queue_max_integrity_segments(rq->q)));
1170
1171		cmd->prot_sdb = prot_sdb;
1172		cmd->prot_sdb->table.nents = count;
1173	}
1174
1175	return BLKPREP_OK;
1176err_exit:
1177	if (is_mq) {
1178		scsi_mq_free_sgtables(cmd);
1179	} else {
1180		scsi_release_buffers(cmd);
1181		cmd->request->special = NULL;
1182		scsi_put_command(cmd);
1183		put_device(&sdev->sdev_gendev);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1184	}
1185	return error;
1186}
1187EXPORT_SYMBOL(scsi_init_io);
1188
1189static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev,
1190		struct request *req)
1191{
1192	struct scsi_cmnd *cmd;
 
 
 
 
 
 
1193
1194	if (!req->special) {
1195		/* Bail if we can't get a reference to the device */
1196		if (!get_device(&sdev->sdev_gendev))
1197			return NULL;
1198
1199		cmd = scsi_get_command(sdev, GFP_ATOMIC);
1200		if (unlikely(!cmd)) {
1201			put_device(&sdev->sdev_gendev);
1202			return NULL;
1203		}
1204		req->special = cmd;
1205	} else {
1206		cmd = req->special;
1207	}
1208
1209	/* pull a tag out of the request if we have one */
1210	cmd->tag = req->tag;
1211	cmd->request = req;
 
 
 
 
 
 
 
 
 
1212
1213	cmd->cmnd = req->cmd;
1214	cmd->prot_op = SCSI_PROT_NORMAL;
 
 
 
 
 
 
 
1215
1216	return cmd;
1217}
1218
1219static int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
 
1220{
1221	struct scsi_cmnd *cmd = req->special;
1222
1223	/*
1224	 * BLOCK_PC requests may transfer data, in which case they must
1225	 * a bio attached to them.  Or they might contain a SCSI command
1226	 * that does not transfer data, in which case they may optionally
1227	 * submit a request without an attached bio.
1228	 */
1229	if (req->bio) {
1230		int ret = scsi_init_io(cmd);
1231		if (unlikely(ret))
1232			return ret;
1233	} else {
1234		BUG_ON(blk_rq_bytes(req));
1235
1236		memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1237	}
1238
1239	cmd->cmd_len = req->cmd_len;
 
1240	cmd->transfersize = blk_rq_bytes(req);
1241	cmd->allowed = req->retries;
1242	return BLKPREP_OK;
1243}
1244
1245/*
1246 * Setup a REQ_TYPE_FS command.  These are simple request from filesystems
1247 * that still need to be translated to SCSI CDBs from the ULD.
1248 */
1249static int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
 
1250{
1251	struct scsi_cmnd *cmd = req->special;
1252
1253	if (unlikely(sdev->handler && sdev->handler->prep_fn)) {
1254		int ret = sdev->handler->prep_fn(sdev, req);
1255		if (ret != BLKPREP_OK)
1256			return ret;
1257	}
1258
 
1259	memset(cmd->cmnd, 0, BLK_MAX_CDB);
1260	return scsi_cmd_to_driver(cmd)->init_command(cmd);
1261}
1262
1263static int scsi_setup_cmnd(struct scsi_device *sdev, struct request *req)
 
1264{
1265	struct scsi_cmnd *cmd = req->special;
 
1266
1267	if (!blk_rq_bytes(req))
1268		cmd->sc_data_direction = DMA_NONE;
1269	else if (rq_data_dir(req) == WRITE)
1270		cmd->sc_data_direction = DMA_TO_DEVICE;
1271	else
1272		cmd->sc_data_direction = DMA_FROM_DEVICE;
1273
1274	switch (req->cmd_type) {
1275	case REQ_TYPE_FS:
1276		return scsi_setup_fs_cmnd(sdev, req);
1277	case REQ_TYPE_BLOCK_PC:
1278		return scsi_setup_blk_pc_cmnd(sdev, req);
1279	default:
1280		return BLKPREP_KILL;
1281	}
 
1282}
1283
1284static int
1285scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
1286{
1287	int ret = BLKPREP_OK;
1288
1289	/*
1290	 * If the device is not in running state we will reject some
1291	 * or all commands.
1292	 */
1293	if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
1294		switch (sdev->sdev_state) {
1295		case SDEV_OFFLINE:
1296		case SDEV_TRANSPORT_OFFLINE:
1297			/*
1298			 * If the device is offline we refuse to process any
1299			 * commands.  The device must be brought online
1300			 * before trying any recovery commands.
1301			 */
1302			sdev_printk(KERN_ERR, sdev,
1303				    "rejecting I/O to offline device\n");
1304			ret = BLKPREP_KILL;
1305			break;
1306		case SDEV_DEL:
1307			/*
1308			 * If the device is fully deleted, we refuse to
1309			 * process any commands as well.
1310			 */
1311			sdev_printk(KERN_ERR, sdev,
1312				    "rejecting I/O to dead device\n");
1313			ret = BLKPREP_KILL;
1314			break;
1315		case SDEV_BLOCK:
1316		case SDEV_CREATED_BLOCK:
1317			ret = BLKPREP_DEFER;
1318			break;
1319		case SDEV_QUIESCE:
1320			/*
1321			 * If the devices is blocked we defer normal commands.
1322			 */
1323			if (!(req->cmd_flags & REQ_PREEMPT))
1324				ret = BLKPREP_DEFER;
1325			break;
1326		default:
1327			/*
1328			 * For any other not fully online state we only allow
1329			 * special commands.  In particular any user initiated
1330			 * command is not allowed.
1331			 */
1332			if (!(req->cmd_flags & REQ_PREEMPT))
1333				ret = BLKPREP_KILL;
1334			break;
1335		}
1336	}
1337	return ret;
1338}
1339
1340static int
1341scsi_prep_return(struct request_queue *q, struct request *req, int ret)
1342{
1343	struct scsi_device *sdev = q->queuedata;
1344
1345	switch (ret) {
1346	case BLKPREP_KILL:
1347	case BLKPREP_INVALID:
1348		req->errors = DID_NO_CONNECT << 16;
1349		/* release the command and kill it */
1350		if (req->special) {
1351			struct scsi_cmnd *cmd = req->special;
1352			scsi_release_buffers(cmd);
1353			scsi_put_command(cmd);
1354			put_device(&sdev->sdev_gendev);
1355			req->special = NULL;
1356		}
1357		break;
1358	case BLKPREP_DEFER:
1359		/*
1360		 * If we defer, the blk_peek_request() returns NULL, but the
1361		 * queue must be restarted, so we schedule a callback to happen
1362		 * shortly.
1363		 */
1364		if (atomic_read(&sdev->device_busy) == 0)
1365			blk_delay_queue(q, SCSI_QUEUE_DELAY);
1366		break;
1367	default:
1368		req->cmd_flags |= REQ_DONTPREP;
 
 
 
 
 
 
 
1369	}
1370
1371	return ret;
1372}
1373
1374static int scsi_prep_fn(struct request_queue *q, struct request *req)
1375{
1376	struct scsi_device *sdev = q->queuedata;
1377	struct scsi_cmnd *cmd;
1378	int ret;
1379
1380	ret = scsi_prep_state_check(sdev, req);
1381	if (ret != BLKPREP_OK)
1382		goto out;
1383
1384	cmd = scsi_get_cmd_from_req(sdev, req);
1385	if (unlikely(!cmd)) {
1386		ret = BLKPREP_DEFER;
1387		goto out;
1388	}
1389
1390	ret = scsi_setup_cmnd(sdev, req);
1391out:
1392	return scsi_prep_return(q, req, ret);
1393}
1394
1395static void scsi_unprep_fn(struct request_queue *q, struct request *req)
1396{
1397	scsi_uninit_cmd(req->special);
1398}
1399
1400/*
1401 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1402 * return 0.
1403 *
1404 * Called with the queue_lock held.
1405 */
1406static inline int scsi_dev_queue_ready(struct request_queue *q,
1407				  struct scsi_device *sdev)
1408{
1409	unsigned int busy;
1410
1411	busy = atomic_inc_return(&sdev->device_busy) - 1;
1412	if (atomic_read(&sdev->device_blocked)) {
1413		if (busy)
1414			goto out_dec;
1415
1416		/*
1417		 * unblock after device_blocked iterates to zero
1418		 */
1419		if (atomic_dec_return(&sdev->device_blocked) > 0) {
1420			/*
1421			 * For the MQ case we take care of this in the caller.
1422			 */
1423			if (!q->mq_ops)
1424				blk_delay_queue(q, SCSI_QUEUE_DELAY);
1425			goto out_dec;
1426		}
1427		SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev,
1428				   "unblocking device at zero depth\n"));
1429	}
1430
1431	if (busy >= sdev->queue_depth)
1432		goto out_dec;
1433
1434	return 1;
1435out_dec:
1436	atomic_dec(&sdev->device_busy);
1437	return 0;
1438}
1439
1440/*
1441 * scsi_target_queue_ready: checks if there we can send commands to target
1442 * @sdev: scsi device on starget to check.
1443 */
1444static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1445					   struct scsi_device *sdev)
1446{
1447	struct scsi_target *starget = scsi_target(sdev);
1448	unsigned int busy;
1449
1450	if (starget->single_lun) {
1451		spin_lock_irq(shost->host_lock);
1452		if (starget->starget_sdev_user &&
1453		    starget->starget_sdev_user != sdev) {
1454			spin_unlock_irq(shost->host_lock);
1455			return 0;
1456		}
1457		starget->starget_sdev_user = sdev;
1458		spin_unlock_irq(shost->host_lock);
1459	}
1460
1461	if (starget->can_queue <= 0)
1462		return 1;
1463
1464	busy = atomic_inc_return(&starget->target_busy) - 1;
1465	if (atomic_read(&starget->target_blocked) > 0) {
1466		if (busy)
1467			goto starved;
1468
1469		/*
1470		 * unblock after target_blocked iterates to zero
1471		 */
1472		if (atomic_dec_return(&starget->target_blocked) > 0)
1473			goto out_dec;
1474
1475		SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1476				 "unblocking target at zero depth\n"));
1477	}
1478
1479	if (busy >= starget->can_queue)
1480		goto starved;
1481
1482	return 1;
1483
1484starved:
1485	spin_lock_irq(shost->host_lock);
1486	list_move_tail(&sdev->starved_entry, &shost->starved_list);
1487	spin_unlock_irq(shost->host_lock);
1488out_dec:
1489	if (starget->can_queue > 0)
1490		atomic_dec(&starget->target_busy);
1491	return 0;
1492}
1493
1494/*
1495 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1496 * return 0. We must end up running the queue again whenever 0 is
1497 * returned, else IO can hang.
1498 */
1499static inline int scsi_host_queue_ready(struct request_queue *q,
1500				   struct Scsi_Host *shost,
1501				   struct scsi_device *sdev)
 
1502{
1503	unsigned int busy;
1504
1505	if (scsi_host_in_recovery(shost))
1506		return 0;
1507
1508	busy = atomic_inc_return(&shost->host_busy) - 1;
1509	if (atomic_read(&shost->host_blocked) > 0) {
1510		if (busy)
1511			goto starved;
1512
1513		/*
1514		 * unblock after host_blocked iterates to zero
1515		 */
1516		if (atomic_dec_return(&shost->host_blocked) > 0)
1517			goto out_dec;
1518
1519		SCSI_LOG_MLQUEUE(3,
1520			shost_printk(KERN_INFO, shost,
1521				     "unblocking host at zero depth\n"));
1522	}
1523
1524	if (shost->can_queue > 0 && busy >= shost->can_queue)
1525		goto starved;
1526	if (shost->host_self_blocked)
1527		goto starved;
1528
1529	/* We're OK to process the command, so we can't be starved */
1530	if (!list_empty(&sdev->starved_entry)) {
1531		spin_lock_irq(shost->host_lock);
1532		if (!list_empty(&sdev->starved_entry))
1533			list_del_init(&sdev->starved_entry);
1534		spin_unlock_irq(shost->host_lock);
1535	}
1536
 
 
1537	return 1;
1538
1539starved:
1540	spin_lock_irq(shost->host_lock);
1541	if (list_empty(&sdev->starved_entry))
1542		list_add_tail(&sdev->starved_entry, &shost->starved_list);
1543	spin_unlock_irq(shost->host_lock);
1544out_dec:
1545	atomic_dec(&shost->host_busy);
1546	return 0;
1547}
1548
1549/*
1550 * Busy state exporting function for request stacking drivers.
1551 *
1552 * For efficiency, no lock is taken to check the busy state of
1553 * shost/starget/sdev, since the returned value is not guaranteed and
1554 * may be changed after request stacking drivers call the function,
1555 * regardless of taking lock or not.
1556 *
1557 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1558 * needs to return 'not busy'. Otherwise, request stacking drivers
1559 * may hold requests forever.
1560 */
1561static int scsi_lld_busy(struct request_queue *q)
1562{
1563	struct scsi_device *sdev = q->queuedata;
1564	struct Scsi_Host *shost;
1565
1566	if (blk_queue_dying(q))
1567		return 0;
1568
1569	shost = sdev->host;
1570
1571	/*
1572	 * Ignore host/starget busy state.
1573	 * Since block layer does not have a concept of fairness across
1574	 * multiple queues, congestion of host/starget needs to be handled
1575	 * in SCSI layer.
1576	 */
1577	if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
1578		return 1;
1579
1580	return 0;
1581}
1582
1583/*
1584 * Kill a request for a dead device
1585 */
1586static void scsi_kill_request(struct request *req, struct request_queue *q)
1587{
1588	struct scsi_cmnd *cmd = req->special;
1589	struct scsi_device *sdev;
1590	struct scsi_target *starget;
1591	struct Scsi_Host *shost;
1592
1593	blk_start_request(req);
1594
1595	scmd_printk(KERN_INFO, cmd, "killing request\n");
1596
1597	sdev = cmd->device;
1598	starget = scsi_target(sdev);
1599	shost = sdev->host;
1600	scsi_init_cmd_errh(cmd);
1601	cmd->result = DID_NO_CONNECT << 16;
1602	atomic_inc(&cmd->device->iorequest_cnt);
1603
1604	/*
1605	 * SCSI request completion path will do scsi_device_unbusy(),
1606	 * bump busy counts.  To bump the counters, we need to dance
1607	 * with the locks as normal issue path does.
1608	 */
1609	atomic_inc(&sdev->device_busy);
1610	atomic_inc(&shost->host_busy);
1611	if (starget->can_queue > 0)
1612		atomic_inc(&starget->target_busy);
1613
1614	blk_complete_request(req);
1615}
1616
1617static void scsi_softirq_done(struct request *rq)
1618{
1619	struct scsi_cmnd *cmd = rq->special;
1620	unsigned long wait_for = (cmd->allowed + 1) * rq->timeout;
1621	int disposition;
1622
1623	INIT_LIST_HEAD(&cmd->eh_entry);
1624
1625	atomic_inc(&cmd->device->iodone_cnt);
1626	if (cmd->result)
1627		atomic_inc(&cmd->device->ioerr_cnt);
1628
1629	disposition = scsi_decide_disposition(cmd);
1630	if (disposition != SUCCESS &&
1631	    time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
1632		sdev_printk(KERN_ERR, cmd->device,
1633			    "timing out command, waited %lus\n",
1634			    wait_for/HZ);
1635		disposition = SUCCESS;
1636	}
1637
1638	scsi_log_completion(cmd, disposition);
1639
1640	switch (disposition) {
1641		case SUCCESS:
1642			scsi_finish_command(cmd);
1643			break;
1644		case NEEDS_RETRY:
1645			scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
1646			break;
1647		case ADD_TO_MLQUEUE:
1648			scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1649			break;
1650		default:
1651			if (!scsi_eh_scmd_add(cmd, 0))
1652				scsi_finish_command(cmd);
1653	}
1654}
1655
1656/**
1657 * scsi_dispatch_command - Dispatch a command to the low-level driver.
1658 * @cmd: command block we are dispatching.
1659 *
1660 * Return: nonzero return request was rejected and device's queue needs to be
1661 * plugged.
1662 */
1663static int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
1664{
1665	struct Scsi_Host *host = cmd->device->host;
1666	int rtn = 0;
1667
1668	atomic_inc(&cmd->device->iorequest_cnt);
1669
1670	/* check if the device is still usable */
1671	if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
1672		/* in SDEV_DEL we error all commands. DID_NO_CONNECT
1673		 * returns an immediate error upwards, and signals
1674		 * that the device is no longer present */
1675		cmd->result = DID_NO_CONNECT << 16;
1676		goto done;
1677	}
1678
1679	/* Check to see if the scsi lld made this device blocked. */
1680	if (unlikely(scsi_device_blocked(cmd->device))) {
1681		/*
1682		 * in blocked state, the command is just put back on
1683		 * the device queue.  The suspend state has already
1684		 * blocked the queue so future requests should not
1685		 * occur until the device transitions out of the
1686		 * suspend state.
1687		 */
1688		SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1689			"queuecommand : device blocked\n"));
1690		return SCSI_MLQUEUE_DEVICE_BUSY;
1691	}
1692
1693	/* Store the LUN value in cmnd, if needed. */
1694	if (cmd->device->lun_in_cdb)
1695		cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
1696			       (cmd->device->lun << 5 & 0xe0);
1697
1698	scsi_log_send(cmd);
1699
1700	/*
1701	 * Before we queue this command, check if the command
1702	 * length exceeds what the host adapter can handle.
1703	 */
1704	if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
1705		SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1706			       "queuecommand : command too long. "
1707			       "cdb_size=%d host->max_cmd_len=%d\n",
1708			       cmd->cmd_len, cmd->device->host->max_cmd_len));
1709		cmd->result = (DID_ABORT << 16);
1710		goto done;
1711	}
1712
1713	if (unlikely(host->shost_state == SHOST_DEL)) {
1714		cmd->result = (DID_NO_CONNECT << 16);
1715		goto done;
1716
1717	}
1718
1719	trace_scsi_dispatch_cmd_start(cmd);
1720	rtn = host->hostt->queuecommand(host, cmd);
1721	if (rtn) {
1722		trace_scsi_dispatch_cmd_error(cmd, rtn);
1723		if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
1724		    rtn != SCSI_MLQUEUE_TARGET_BUSY)
1725			rtn = SCSI_MLQUEUE_HOST_BUSY;
1726
1727		SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1728			"queuecommand : request rejected\n"));
1729	}
1730
1731	return rtn;
1732 done:
1733	cmd->scsi_done(cmd);
1734	return 0;
1735}
1736
1737/**
1738 * scsi_done - Invoke completion on finished SCSI command.
1739 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
1740 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
1741 *
1742 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
1743 * which regains ownership of the SCSI command (de facto) from a LLDD, and
1744 * calls blk_complete_request() for further processing.
1745 *
1746 * This function is interrupt context safe.
1747 */
1748static void scsi_done(struct scsi_cmnd *cmd)
1749{
1750	trace_scsi_dispatch_cmd_done(cmd);
1751	blk_complete_request(cmd->request);
1752}
1753
1754/*
1755 * Function:    scsi_request_fn()
1756 *
1757 * Purpose:     Main strategy routine for SCSI.
1758 *
1759 * Arguments:   q       - Pointer to actual queue.
1760 *
1761 * Returns:     Nothing
1762 *
1763 * Lock status: IO request lock assumed to be held when called.
1764 */
1765static void scsi_request_fn(struct request_queue *q)
1766	__releases(q->queue_lock)
1767	__acquires(q->queue_lock)
1768{
1769	struct scsi_device *sdev = q->queuedata;
1770	struct Scsi_Host *shost;
1771	struct scsi_cmnd *cmd;
1772	struct request *req;
1773
1774	/*
1775	 * To start with, we keep looping until the queue is empty, or until
1776	 * the host is no longer able to accept any more requests.
1777	 */
1778	shost = sdev->host;
1779	for (;;) {
1780		int rtn;
1781		/*
1782		 * get next queueable request.  We do this early to make sure
1783		 * that the request is fully prepared even if we cannot
1784		 * accept it.
1785		 */
1786		req = blk_peek_request(q);
1787		if (!req)
1788			break;
1789
1790		if (unlikely(!scsi_device_online(sdev))) {
1791			sdev_printk(KERN_ERR, sdev,
1792				    "rejecting I/O to offline device\n");
1793			scsi_kill_request(req, q);
1794			continue;
1795		}
1796
1797		if (!scsi_dev_queue_ready(q, sdev))
1798			break;
1799
1800		/*
1801		 * Remove the request from the request list.
1802		 */
1803		if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req)))
1804			blk_start_request(req);
1805
1806		spin_unlock_irq(q->queue_lock);
1807		cmd = req->special;
1808		if (unlikely(cmd == NULL)) {
1809			printk(KERN_CRIT "impossible request in %s.\n"
1810					 "please mail a stack trace to "
1811					 "linux-scsi@vger.kernel.org\n",
1812					 __func__);
1813			blk_dump_rq_flags(req, "foo");
1814			BUG();
1815		}
1816
1817		/*
1818		 * We hit this when the driver is using a host wide
1819		 * tag map. For device level tag maps the queue_depth check
1820		 * in the device ready fn would prevent us from trying
1821		 * to allocate a tag. Since the map is a shared host resource
1822		 * we add the dev to the starved list so it eventually gets
1823		 * a run when a tag is freed.
1824		 */
1825		if (blk_queue_tagged(q) && !(req->cmd_flags & REQ_QUEUED)) {
1826			spin_lock_irq(shost->host_lock);
1827			if (list_empty(&sdev->starved_entry))
1828				list_add_tail(&sdev->starved_entry,
1829					      &shost->starved_list);
1830			spin_unlock_irq(shost->host_lock);
1831			goto not_ready;
1832		}
1833
1834		if (!scsi_target_queue_ready(shost, sdev))
1835			goto not_ready;
1836
1837		if (!scsi_host_queue_ready(q, shost, sdev))
1838			goto host_not_ready;
1839	
1840		if (sdev->simple_tags)
1841			cmd->flags |= SCMD_TAGGED;
1842		else
1843			cmd->flags &= ~SCMD_TAGGED;
1844
1845		/*
1846		 * Finally, initialize any error handling parameters, and set up
1847		 * the timers for timeouts.
1848		 */
1849		scsi_init_cmd_errh(cmd);
1850
1851		/*
1852		 * Dispatch the command to the low-level driver.
1853		 */
1854		cmd->scsi_done = scsi_done;
1855		rtn = scsi_dispatch_cmd(cmd);
1856		if (rtn) {
1857			scsi_queue_insert(cmd, rtn);
1858			spin_lock_irq(q->queue_lock);
1859			goto out_delay;
1860		}
1861		spin_lock_irq(q->queue_lock);
1862	}
1863
1864	return;
1865
1866 host_not_ready:
1867	if (scsi_target(sdev)->can_queue > 0)
1868		atomic_dec(&scsi_target(sdev)->target_busy);
1869 not_ready:
1870	/*
1871	 * lock q, handle tag, requeue req, and decrement device_busy. We
1872	 * must return with queue_lock held.
1873	 *
1874	 * Decrementing device_busy without checking it is OK, as all such
1875	 * cases (host limits or settings) should run the queue at some
1876	 * later time.
1877	 */
1878	spin_lock_irq(q->queue_lock);
1879	blk_requeue_request(q, req);
1880	atomic_dec(&sdev->device_busy);
1881out_delay:
1882	if (!atomic_read(&sdev->device_busy) && !scsi_device_blocked(sdev))
1883		blk_delay_queue(q, SCSI_QUEUE_DELAY);
1884}
1885
1886static inline int prep_to_mq(int ret)
1887{
1888	switch (ret) {
1889	case BLKPREP_OK:
1890		return 0;
1891	case BLKPREP_DEFER:
1892		return BLK_MQ_RQ_QUEUE_BUSY;
1893	default:
1894		return BLK_MQ_RQ_QUEUE_ERROR;
1895	}
1896}
1897
1898static int scsi_mq_prep_fn(struct request *req)
1899{
1900	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1901	struct scsi_device *sdev = req->q->queuedata;
1902	struct Scsi_Host *shost = sdev->host;
1903	unsigned char *sense_buf = cmd->sense_buffer;
1904	struct scatterlist *sg;
1905
1906	memset(cmd, 0, sizeof(struct scsi_cmnd));
1907
1908	req->special = cmd;
1909
1910	cmd->request = req;
1911	cmd->device = sdev;
1912	cmd->sense_buffer = sense_buf;
1913
1914	cmd->tag = req->tag;
1915
1916	cmd->cmnd = req->cmd;
1917	cmd->prot_op = SCSI_PROT_NORMAL;
1918
1919	INIT_LIST_HEAD(&cmd->list);
1920	INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
1921	cmd->jiffies_at_alloc = jiffies;
1922
1923	if (shost->use_cmd_list) {
1924		spin_lock_irq(&sdev->list_lock);
1925		list_add_tail(&cmd->list, &sdev->cmd_list);
1926		spin_unlock_irq(&sdev->list_lock);
1927	}
1928
1929	sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
1930	cmd->sdb.table.sgl = sg;
1931
1932	if (scsi_host_get_prot(shost)) {
1933		cmd->prot_sdb = (void *)sg +
1934			min_t(unsigned int,
1935			      shost->sg_tablesize, SCSI_MAX_SG_SEGMENTS) *
1936			sizeof(struct scatterlist);
1937		memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer));
1938
1939		cmd->prot_sdb->table.sgl =
1940			(struct scatterlist *)(cmd->prot_sdb + 1);
1941	}
1942
1943	if (blk_bidi_rq(req)) {
1944		struct request *next_rq = req->next_rq;
1945		struct scsi_data_buffer *bidi_sdb = blk_mq_rq_to_pdu(next_rq);
1946
1947		memset(bidi_sdb, 0, sizeof(struct scsi_data_buffer));
1948		bidi_sdb->table.sgl =
1949			(struct scatterlist *)(bidi_sdb + 1);
1950
1951		next_rq->special = bidi_sdb;
1952	}
1953
1954	blk_mq_start_request(req);
1955
1956	return scsi_setup_cmnd(sdev, req);
1957}
1958
1959static void scsi_mq_done(struct scsi_cmnd *cmd)
1960{
 
 
 
 
1961	trace_scsi_dispatch_cmd_done(cmd);
1962	blk_mq_complete_request(cmd->request, cmd->request->errors);
1963}
1964
1965static int scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1966			 const struct blk_mq_queue_data *bd)
1967{
1968	struct request *req = bd->rq;
1969	struct request_queue *q = req->q;
1970	struct scsi_device *sdev = q->queuedata;
1971	struct Scsi_Host *shost = sdev->host;
1972	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1973	int ret;
1974	int reason;
1975
1976	ret = prep_to_mq(scsi_prep_state_check(sdev, req));
1977	if (ret)
1978		goto out;
1979
1980	ret = BLK_MQ_RQ_QUEUE_BUSY;
1981	if (!get_device(&sdev->sdev_gendev))
1982		goto out;
 
 
1983
1984	if (!scsi_dev_queue_ready(q, sdev))
1985		goto out_put_device;
1986	if (!scsi_target_queue_ready(shost, sdev))
1987		goto out_dec_device_busy;
1988	if (!scsi_host_queue_ready(q, shost, sdev))
1989		goto out_dec_target_busy;
1990
1991
1992	if (!(req->cmd_flags & REQ_DONTPREP)) {
1993		ret = prep_to_mq(scsi_mq_prep_fn(req));
1994		if (ret)
1995			goto out_dec_host_busy;
1996		req->cmd_flags |= REQ_DONTPREP;
1997	} else {
 
1998		blk_mq_start_request(req);
1999	}
2000
 
2001	if (sdev->simple_tags)
2002		cmd->flags |= SCMD_TAGGED;
2003	else
2004		cmd->flags &= ~SCMD_TAGGED;
2005
2006	scsi_init_cmd_errh(cmd);
2007	cmd->scsi_done = scsi_mq_done;
2008
2009	reason = scsi_dispatch_cmd(cmd);
2010	if (reason) {
2011		scsi_set_blocked(cmd, reason);
2012		ret = BLK_MQ_RQ_QUEUE_BUSY;
2013		goto out_dec_host_busy;
2014	}
2015
2016	return BLK_MQ_RQ_QUEUE_OK;
2017
2018out_dec_host_busy:
2019	atomic_dec(&shost->host_busy);
2020out_dec_target_busy:
2021	if (scsi_target(sdev)->can_queue > 0)
2022		atomic_dec(&scsi_target(sdev)->target_busy);
2023out_dec_device_busy:
2024	atomic_dec(&sdev->device_busy);
2025out_put_device:
2026	put_device(&sdev->sdev_gendev);
2027out:
2028	switch (ret) {
2029	case BLK_MQ_RQ_QUEUE_BUSY:
2030		blk_mq_stop_hw_queue(hctx);
2031		if (atomic_read(&sdev->device_busy) == 0 &&
2032		    !scsi_device_blocked(sdev))
2033			blk_mq_delay_queue(hctx, SCSI_QUEUE_DELAY);
2034		break;
2035	case BLK_MQ_RQ_QUEUE_ERROR:
 
 
 
 
 
 
 
 
 
 
2036		/*
2037		 * Make sure to release all allocated ressources when
2038		 * we hit an error, as we will never see this command
2039		 * again.
2040		 */
2041		if (req->cmd_flags & REQ_DONTPREP)
2042			scsi_mq_uninit_cmd(cmd);
2043		break;
2044	default:
2045		break;
2046	}
2047	return ret;
2048}
2049
2050static enum blk_eh_timer_return scsi_timeout(struct request *req,
2051		bool reserved)
2052{
2053	if (reserved)
2054		return BLK_EH_RESET_TIMER;
2055	return scsi_times_out(req);
2056}
2057
2058static int scsi_init_request(void *data, struct request *rq,
2059		unsigned int hctx_idx, unsigned int request_idx,
2060		unsigned int numa_node)
2061{
 
 
2062	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
 
 
2063
2064	cmd->sense_buffer = kzalloc_node(SCSI_SENSE_BUFFERSIZE, GFP_KERNEL,
2065			numa_node);
 
 
2066	if (!cmd->sense_buffer)
2067		return -ENOMEM;
2068	return 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2069}
2070
2071static void scsi_exit_request(void *data, struct request *rq,
2072		unsigned int hctx_idx, unsigned int request_idx)
2073{
 
2074	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
2075
2076	kfree(cmd->sense_buffer);
 
 
 
2077}
2078
2079static u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost)
2080{
2081	struct device *host_dev;
2082	u64 bounce_limit = 0xffffffff;
2083
2084	if (shost->unchecked_isa_dma)
2085		return BLK_BOUNCE_ISA;
2086	/*
2087	 * Platforms with virtual-DMA translation
2088	 * hardware have no practical limit.
2089	 */
2090	if (!PCI_DMA_BUS_IS_PHYS)
2091		return BLK_BOUNCE_ANY;
2092
2093	host_dev = scsi_get_device(shost);
2094	if (host_dev && host_dev->dma_mask)
2095		bounce_limit = (u64)dma_max_pfn(host_dev) << PAGE_SHIFT;
2096
2097	return bounce_limit;
2098}
2099
2100static void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
2101{
2102	struct device *dev = shost->dma_dev;
2103
2104	/*
2105	 * this limit is imposed by hardware restrictions
2106	 */
2107	blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
2108					SCSI_MAX_SG_CHAIN_SEGMENTS));
2109
2110	if (scsi_host_prot_dma(shost)) {
2111		shost->sg_prot_tablesize =
2112			min_not_zero(shost->sg_prot_tablesize,
2113				     (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
2114		BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
2115		blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
2116	}
2117
 
 
 
 
2118	blk_queue_max_hw_sectors(q, shost->max_sectors);
2119	blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost));
 
2120	blk_queue_segment_boundary(q, shost->dma_boundary);
2121	dma_set_seg_boundary(dev, shost->dma_boundary);
2122
2123	blk_queue_max_segment_size(q, dma_get_max_seg_size(dev));
2124
2125	if (!shost->use_clustering)
2126		q->limits.cluster = 0;
2127
2128	/*
2129	 * set a reasonable default alignment on word boundaries: the
2130	 * host and device may alter it using
2131	 * blk_queue_update_dma_alignment() later.
 
 
2132	 */
2133	blk_queue_dma_alignment(q, 0x03);
2134}
 
2135
2136struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost,
2137					 request_fn_proc *request_fn)
2138{
2139	struct request_queue *q;
 
 
 
 
 
 
 
 
 
 
 
 
2140
2141	q = blk_init_queue(request_fn, NULL);
2142	if (!q)
2143		return NULL;
2144	__scsi_init_queue(shost, q);
2145	return q;
2146}
2147EXPORT_SYMBOL(__scsi_alloc_queue);
2148
2149struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
2150{
2151	struct request_queue *q;
 
 
2152
2153	q = __scsi_alloc_queue(sdev->host, scsi_request_fn);
2154	if (!q)
2155		return NULL;
2156
2157	blk_queue_prep_rq(q, scsi_prep_fn);
2158	blk_queue_unprep_rq(q, scsi_unprep_fn);
2159	blk_queue_softirq_done(q, scsi_softirq_done);
2160	blk_queue_rq_timed_out(q, scsi_times_out);
2161	blk_queue_lld_busy(q, scsi_lld_busy);
2162	return q;
2163}
2164
2165static struct blk_mq_ops scsi_mq_ops = {
2166	.map_queue	= blk_mq_map_queue,
 
2167	.queue_rq	= scsi_queue_rq,
 
2168	.complete	= scsi_softirq_done,
2169	.timeout	= scsi_timeout,
2170	.init_request	= scsi_init_request,
2171	.exit_request	= scsi_exit_request,
 
 
 
 
 
 
 
2172};
2173
2174struct request_queue *scsi_mq_alloc_queue(struct scsi_device *sdev)
2175{
2176	sdev->request_queue = blk_mq_init_queue(&sdev->host->tag_set);
2177	if (IS_ERR(sdev->request_queue))
2178		return NULL;
2179
2180	sdev->request_queue->queuedata = sdev;
2181	__scsi_init_queue(sdev->host, sdev->request_queue);
 
2182	return sdev->request_queue;
2183}
2184
2185int scsi_mq_setup_tags(struct Scsi_Host *shost)
2186{
2187	unsigned int cmd_size, sgl_size, tbl_size;
 
2188
2189	tbl_size = shost->sg_tablesize;
2190	if (tbl_size > SCSI_MAX_SG_SEGMENTS)
2191		tbl_size = SCSI_MAX_SG_SEGMENTS;
2192	sgl_size = tbl_size * sizeof(struct scatterlist);
2193	cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size;
2194	if (scsi_host_get_prot(shost))
2195		cmd_size += sizeof(struct scsi_data_buffer) + sgl_size;
 
2196
2197	memset(&shost->tag_set, 0, sizeof(shost->tag_set));
2198	shost->tag_set.ops = &scsi_mq_ops;
2199	shost->tag_set.nr_hw_queues = shost->nr_hw_queues ? : 1;
2200	shost->tag_set.queue_depth = shost->can_queue;
2201	shost->tag_set.cmd_size = cmd_size;
2202	shost->tag_set.numa_node = NUMA_NO_NODE;
2203	shost->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
2204	shost->tag_set.flags |=
 
 
 
2205		BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
2206	shost->tag_set.driver_data = shost;
2207
2208	return blk_mq_alloc_tag_set(&shost->tag_set);
2209}
2210
2211void scsi_mq_destroy_tags(struct Scsi_Host *shost)
2212{
2213	blk_mq_free_tag_set(&shost->tag_set);
2214}
2215
2216/*
2217 * Function:    scsi_block_requests()
 
2218 *
2219 * Purpose:     Utility function used by low-level drivers to prevent further
2220 *		commands from being queued to the device.
2221 *
2222 * Arguments:   shost       - Host in question
2223 *
2224 * Returns:     Nothing
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2225 *
2226 * Lock status: No locks are assumed held.
2227 *
2228 * Notes:       There is no timer nor any other means by which the requests
2229 *		get unblocked other than the low-level driver calling
2230 *		scsi_unblock_requests().
2231 */
2232void scsi_block_requests(struct Scsi_Host *shost)
2233{
2234	shost->host_self_blocked = 1;
2235}
2236EXPORT_SYMBOL(scsi_block_requests);
2237
2238/*
2239 * Function:    scsi_unblock_requests()
2240 *
2241 * Purpose:     Utility function used by low-level drivers to allow further
2242 *		commands from being queued to the device.
2243 *
2244 * Arguments:   shost       - Host in question
2245 *
2246 * Returns:     Nothing
2247 *
2248 * Lock status: No locks are assumed held.
2249 *
2250 * Notes:       There is no timer nor any other means by which the requests
2251 *		get unblocked other than the low-level driver calling
2252 *		scsi_unblock_requests().
2253 *
2254 *		This is done as an API function so that changes to the
2255 *		internals of the scsi mid-layer won't require wholesale
2256 *		changes to drivers that use this feature.
2257 */
2258void scsi_unblock_requests(struct Scsi_Host *shost)
2259{
2260	shost->host_self_blocked = 0;
2261	scsi_run_host_queues(shost);
2262}
2263EXPORT_SYMBOL(scsi_unblock_requests);
2264
2265int __init scsi_init_queue(void)
2266{
2267	int i;
2268
2269	scsi_sdb_cache = kmem_cache_create("scsi_data_buffer",
2270					   sizeof(struct scsi_data_buffer),
2271					   0, 0, NULL);
2272	if (!scsi_sdb_cache) {
2273		printk(KERN_ERR "SCSI: can't init scsi sdb cache\n");
2274		return -ENOMEM;
2275	}
2276
2277	for (i = 0; i < SG_MEMPOOL_NR; i++) {
2278		struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
2279		int size = sgp->size * sizeof(struct scatterlist);
2280
2281		sgp->slab = kmem_cache_create(sgp->name, size, 0,
2282				SLAB_HWCACHE_ALIGN, NULL);
2283		if (!sgp->slab) {
2284			printk(KERN_ERR "SCSI: can't init sg slab %s\n",
2285					sgp->name);
2286			goto cleanup_sdb;
2287		}
2288
2289		sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE,
2290						     sgp->slab);
2291		if (!sgp->pool) {
2292			printk(KERN_ERR "SCSI: can't init sg mempool %s\n",
2293					sgp->name);
2294			goto cleanup_sdb;
2295		}
2296	}
2297
2298	return 0;
2299
2300cleanup_sdb:
2301	for (i = 0; i < SG_MEMPOOL_NR; i++) {
2302		struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
2303		if (sgp->pool)
2304			mempool_destroy(sgp->pool);
2305		if (sgp->slab)
2306			kmem_cache_destroy(sgp->slab);
2307	}
2308	kmem_cache_destroy(scsi_sdb_cache);
2309
2310	return -ENOMEM;
2311}
2312
2313void scsi_exit_queue(void)
2314{
2315	int i;
2316
2317	kmem_cache_destroy(scsi_sdb_cache);
2318
2319	for (i = 0; i < SG_MEMPOOL_NR; i++) {
2320		struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
2321		mempool_destroy(sgp->pool);
2322		kmem_cache_destroy(sgp->slab);
2323	}
2324}
2325
2326/**
2327 *	scsi_mode_select - issue a mode select
2328 *	@sdev:	SCSI device to be queried
2329 *	@pf:	Page format bit (1 == standard, 0 == vendor specific)
2330 *	@sp:	Save page bit (0 == don't save, 1 == save)
2331 *	@modepage: mode page being requested
2332 *	@buffer: request buffer (may not be smaller than eight bytes)
2333 *	@len:	length of request buffer.
2334 *	@timeout: command timeout
2335 *	@retries: number of retries before failing
2336 *	@data: returns a structure abstracting the mode header data
2337 *	@sshdr: place to put sense data (or NULL if no sense to be collected).
2338 *		must be SCSI_SENSE_BUFFERSIZE big.
2339 *
2340 *	Returns zero if successful; negative error number or scsi
2341 *	status on error
2342 *
2343 */
2344int
2345scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
2346		 unsigned char *buffer, int len, int timeout, int retries,
2347		 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2348{
2349	unsigned char cmd[10];
2350	unsigned char *real_buffer;
2351	int ret;
2352
2353	memset(cmd, 0, sizeof(cmd));
2354	cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
2355
2356	if (sdev->use_10_for_ms) {
2357		if (len > 65535)
2358			return -EINVAL;
2359		real_buffer = kmalloc(8 + len, GFP_KERNEL);
2360		if (!real_buffer)
2361			return -ENOMEM;
2362		memcpy(real_buffer + 8, buffer, len);
2363		len += 8;
2364		real_buffer[0] = 0;
2365		real_buffer[1] = 0;
2366		real_buffer[2] = data->medium_type;
2367		real_buffer[3] = data->device_specific;
2368		real_buffer[4] = data->longlba ? 0x01 : 0;
2369		real_buffer[5] = 0;
2370		real_buffer[6] = data->block_descriptor_length >> 8;
2371		real_buffer[7] = data->block_descriptor_length;
2372
2373		cmd[0] = MODE_SELECT_10;
2374		cmd[7] = len >> 8;
2375		cmd[8] = len;
2376	} else {
2377		if (len > 255 || data->block_descriptor_length > 255 ||
2378		    data->longlba)
2379			return -EINVAL;
2380
2381		real_buffer = kmalloc(4 + len, GFP_KERNEL);
2382		if (!real_buffer)
2383			return -ENOMEM;
2384		memcpy(real_buffer + 4, buffer, len);
2385		len += 4;
2386		real_buffer[0] = 0;
2387		real_buffer[1] = data->medium_type;
2388		real_buffer[2] = data->device_specific;
2389		real_buffer[3] = data->block_descriptor_length;
2390		
2391
2392		cmd[0] = MODE_SELECT;
2393		cmd[4] = len;
2394	}
2395
2396	ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
2397			       sshdr, timeout, retries, NULL);
2398	kfree(real_buffer);
2399	return ret;
2400}
2401EXPORT_SYMBOL_GPL(scsi_mode_select);
2402
2403/**
2404 *	scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
2405 *	@sdev:	SCSI device to be queried
2406 *	@dbd:	set if mode sense will allow block descriptors to be returned
2407 *	@modepage: mode page being requested
2408 *	@buffer: request buffer (may not be smaller than eight bytes)
2409 *	@len:	length of request buffer.
2410 *	@timeout: command timeout
2411 *	@retries: number of retries before failing
2412 *	@data: returns a structure abstracting the mode header data
2413 *	@sshdr: place to put sense data (or NULL if no sense to be collected).
2414 *		must be SCSI_SENSE_BUFFERSIZE big.
2415 *
2416 *	Returns zero if unsuccessful, or the header offset (either 4
2417 *	or 8 depending on whether a six or ten byte command was
2418 *	issued) if successful.
2419 */
2420int
2421scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
2422		  unsigned char *buffer, int len, int timeout, int retries,
2423		  struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2424{
2425	unsigned char cmd[12];
2426	int use_10_for_ms;
2427	int header_length;
2428	int result, retry_count = retries;
2429	struct scsi_sense_hdr my_sshdr;
2430
2431	memset(data, 0, sizeof(*data));
2432	memset(&cmd[0], 0, 12);
 
 
2433	cmd[1] = dbd & 0x18;	/* allows DBD and LLBA bits */
2434	cmd[2] = modepage;
2435
2436	/* caller might not be interested in sense, but we need it */
2437	if (!sshdr)
2438		sshdr = &my_sshdr;
2439
2440 retry:
2441	use_10_for_ms = sdev->use_10_for_ms;
2442
2443	if (use_10_for_ms) {
2444		if (len < 8)
2445			len = 8;
2446
2447		cmd[0] = MODE_SENSE_10;
2448		cmd[8] = len;
2449		header_length = 8;
2450	} else {
2451		if (len < 4)
2452			len = 4;
2453
2454		cmd[0] = MODE_SENSE;
2455		cmd[4] = len;
2456		header_length = 4;
2457	}
2458
2459	memset(buffer, 0, len);
2460
2461	result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
2462				  sshdr, timeout, retries, NULL);
2463
2464	/* This code looks awful: what it's doing is making sure an
2465	 * ILLEGAL REQUEST sense return identifies the actual command
2466	 * byte as the problem.  MODE_SENSE commands can return
2467	 * ILLEGAL REQUEST if the code page isn't supported */
2468
2469	if (use_10_for_ms && !scsi_status_is_good(result) &&
2470	    (driver_byte(result) & DRIVER_SENSE)) {
2471		if (scsi_sense_valid(sshdr)) {
2472			if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
2473			    (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
2474				/* 
2475				 * Invalid command operation code
2476				 */
2477				sdev->use_10_for_ms = 0;
2478				goto retry;
2479			}
2480		}
2481	}
2482
2483	if(scsi_status_is_good(result)) {
2484		if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
2485			     (modepage == 6 || modepage == 8))) {
2486			/* Initio breakage? */
2487			header_length = 0;
2488			data->length = 13;
2489			data->medium_type = 0;
2490			data->device_specific = 0;
2491			data->longlba = 0;
2492			data->block_descriptor_length = 0;
2493		} else if(use_10_for_ms) {
2494			data->length = buffer[0]*256 + buffer[1] + 2;
2495			data->medium_type = buffer[2];
2496			data->device_specific = buffer[3];
2497			data->longlba = buffer[4] & 0x01;
2498			data->block_descriptor_length = buffer[6]*256
2499				+ buffer[7];
2500		} else {
2501			data->length = buffer[0] + 1;
2502			data->medium_type = buffer[1];
2503			data->device_specific = buffer[2];
2504			data->block_descriptor_length = buffer[3];
2505		}
2506		data->header_length = header_length;
2507	} else if ((status_byte(result) == CHECK_CONDITION) &&
2508		   scsi_sense_valid(sshdr) &&
2509		   sshdr->sense_key == UNIT_ATTENTION && retry_count) {
2510		retry_count--;
2511		goto retry;
2512	}
2513
2514	return result;
2515}
2516EXPORT_SYMBOL(scsi_mode_sense);
2517
2518/**
2519 *	scsi_test_unit_ready - test if unit is ready
2520 *	@sdev:	scsi device to change the state of.
2521 *	@timeout: command timeout
2522 *	@retries: number of retries before failing
2523 *	@sshdr_external: Optional pointer to struct scsi_sense_hdr for
2524 *		returning sense. Make sure that this is cleared before passing
2525 *		in.
2526 *
2527 *	Returns zero if unsuccessful or an error if TUR failed.  For
2528 *	removable media, UNIT_ATTENTION sets ->changed flag.
2529 **/
2530int
2531scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2532		     struct scsi_sense_hdr *sshdr_external)
2533{
2534	char cmd[] = {
2535		TEST_UNIT_READY, 0, 0, 0, 0, 0,
2536	};
2537	struct scsi_sense_hdr *sshdr;
2538	int result;
2539
2540	if (!sshdr_external)
2541		sshdr = kzalloc(sizeof(*sshdr), GFP_KERNEL);
2542	else
2543		sshdr = sshdr_external;
2544
2545	/* try to eat the UNIT_ATTENTION if there are enough retries */
2546	do {
2547		result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
2548					  timeout, retries, NULL);
2549		if (sdev->removable && scsi_sense_valid(sshdr) &&
2550		    sshdr->sense_key == UNIT_ATTENTION)
2551			sdev->changed = 1;
2552	} while (scsi_sense_valid(sshdr) &&
2553		 sshdr->sense_key == UNIT_ATTENTION && --retries);
2554
2555	if (!sshdr_external)
2556		kfree(sshdr);
2557	return result;
2558}
2559EXPORT_SYMBOL(scsi_test_unit_ready);
2560
2561/**
2562 *	scsi_device_set_state - Take the given device through the device state model.
2563 *	@sdev:	scsi device to change the state of.
2564 *	@state:	state to change to.
2565 *
2566 *	Returns zero if unsuccessful or an error if the requested 
2567 *	transition is illegal.
2568 */
2569int
2570scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2571{
2572	enum scsi_device_state oldstate = sdev->sdev_state;
2573
2574	if (state == oldstate)
2575		return 0;
2576
2577	switch (state) {
2578	case SDEV_CREATED:
2579		switch (oldstate) {
2580		case SDEV_CREATED_BLOCK:
2581			break;
2582		default:
2583			goto illegal;
2584		}
2585		break;
2586			
2587	case SDEV_RUNNING:
2588		switch (oldstate) {
2589		case SDEV_CREATED:
2590		case SDEV_OFFLINE:
2591		case SDEV_TRANSPORT_OFFLINE:
2592		case SDEV_QUIESCE:
2593		case SDEV_BLOCK:
2594			break;
2595		default:
2596			goto illegal;
2597		}
2598		break;
2599
2600	case SDEV_QUIESCE:
2601		switch (oldstate) {
2602		case SDEV_RUNNING:
2603		case SDEV_OFFLINE:
2604		case SDEV_TRANSPORT_OFFLINE:
2605			break;
2606		default:
2607			goto illegal;
2608		}
2609		break;
2610
2611	case SDEV_OFFLINE:
2612	case SDEV_TRANSPORT_OFFLINE:
2613		switch (oldstate) {
2614		case SDEV_CREATED:
2615		case SDEV_RUNNING:
2616		case SDEV_QUIESCE:
2617		case SDEV_BLOCK:
2618			break;
2619		default:
2620			goto illegal;
2621		}
2622		break;
2623
2624	case SDEV_BLOCK:
2625		switch (oldstate) {
2626		case SDEV_RUNNING:
2627		case SDEV_CREATED_BLOCK:
 
 
2628			break;
2629		default:
2630			goto illegal;
2631		}
2632		break;
2633
2634	case SDEV_CREATED_BLOCK:
2635		switch (oldstate) {
2636		case SDEV_CREATED:
2637			break;
2638		default:
2639			goto illegal;
2640		}
2641		break;
2642
2643	case SDEV_CANCEL:
2644		switch (oldstate) {
2645		case SDEV_CREATED:
2646		case SDEV_RUNNING:
2647		case SDEV_QUIESCE:
2648		case SDEV_OFFLINE:
2649		case SDEV_TRANSPORT_OFFLINE:
2650		case SDEV_BLOCK:
2651			break;
2652		default:
2653			goto illegal;
2654		}
2655		break;
2656
2657	case SDEV_DEL:
2658		switch (oldstate) {
2659		case SDEV_CREATED:
2660		case SDEV_RUNNING:
2661		case SDEV_OFFLINE:
2662		case SDEV_TRANSPORT_OFFLINE:
2663		case SDEV_CANCEL:
 
2664		case SDEV_CREATED_BLOCK:
2665			break;
2666		default:
2667			goto illegal;
2668		}
2669		break;
2670
2671	}
 
2672	sdev->sdev_state = state;
2673	return 0;
2674
2675 illegal:
2676	SCSI_LOG_ERROR_RECOVERY(1,
2677				sdev_printk(KERN_ERR, sdev,
2678					    "Illegal state transition %s->%s",
2679					    scsi_device_state_name(oldstate),
2680					    scsi_device_state_name(state))
2681				);
2682	return -EINVAL;
2683}
2684EXPORT_SYMBOL(scsi_device_set_state);
2685
2686/**
2687 * 	sdev_evt_emit - emit a single SCSI device uevent
2688 *	@sdev: associated SCSI device
2689 *	@evt: event to emit
2690 *
2691 *	Send a single uevent (scsi_event) to the associated scsi_device.
2692 */
2693static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2694{
2695	int idx = 0;
2696	char *envp[3];
2697
2698	switch (evt->evt_type) {
2699	case SDEV_EVT_MEDIA_CHANGE:
2700		envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2701		break;
2702	case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2703		scsi_rescan_device(&sdev->sdev_gendev);
2704		envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2705		break;
2706	case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2707		envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2708		break;
2709	case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2710	       envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2711		break;
2712	case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2713		envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2714		break;
2715	case SDEV_EVT_LUN_CHANGE_REPORTED:
2716		envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2717		break;
2718	case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2719		envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
2720		break;
 
 
 
2721	default:
2722		/* do nothing */
2723		break;
2724	}
2725
2726	envp[idx++] = NULL;
2727
2728	kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2729}
2730
2731/**
2732 * 	sdev_evt_thread - send a uevent for each scsi event
2733 *	@work: work struct for scsi_device
2734 *
2735 *	Dispatch queued events to their associated scsi_device kobjects
2736 *	as uevents.
2737 */
2738void scsi_evt_thread(struct work_struct *work)
2739{
2740	struct scsi_device *sdev;
2741	enum scsi_device_event evt_type;
2742	LIST_HEAD(event_list);
2743
2744	sdev = container_of(work, struct scsi_device, event_work);
2745
2746	for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
2747		if (test_and_clear_bit(evt_type, sdev->pending_events))
2748			sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
2749
2750	while (1) {
2751		struct scsi_event *evt;
2752		struct list_head *this, *tmp;
2753		unsigned long flags;
2754
2755		spin_lock_irqsave(&sdev->list_lock, flags);
2756		list_splice_init(&sdev->event_list, &event_list);
2757		spin_unlock_irqrestore(&sdev->list_lock, flags);
2758
2759		if (list_empty(&event_list))
2760			break;
2761
2762		list_for_each_safe(this, tmp, &event_list) {
2763			evt = list_entry(this, struct scsi_event, node);
2764			list_del(&evt->node);
2765			scsi_evt_emit(sdev, evt);
2766			kfree(evt);
2767		}
2768	}
2769}
2770
2771/**
2772 * 	sdev_evt_send - send asserted event to uevent thread
2773 *	@sdev: scsi_device event occurred on
2774 *	@evt: event to send
2775 *
2776 *	Assert scsi device event asynchronously.
2777 */
2778void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2779{
2780	unsigned long flags;
2781
2782#if 0
2783	/* FIXME: currently this check eliminates all media change events
2784	 * for polled devices.  Need to update to discriminate between AN
2785	 * and polled events */
2786	if (!test_bit(evt->evt_type, sdev->supported_events)) {
2787		kfree(evt);
2788		return;
2789	}
2790#endif
2791
2792	spin_lock_irqsave(&sdev->list_lock, flags);
2793	list_add_tail(&evt->node, &sdev->event_list);
2794	schedule_work(&sdev->event_work);
2795	spin_unlock_irqrestore(&sdev->list_lock, flags);
2796}
2797EXPORT_SYMBOL_GPL(sdev_evt_send);
2798
2799/**
2800 * 	sdev_evt_alloc - allocate a new scsi event
2801 *	@evt_type: type of event to allocate
2802 *	@gfpflags: GFP flags for allocation
2803 *
2804 *	Allocates and returns a new scsi_event.
2805 */
2806struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2807				  gfp_t gfpflags)
2808{
2809	struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2810	if (!evt)
2811		return NULL;
2812
2813	evt->evt_type = evt_type;
2814	INIT_LIST_HEAD(&evt->node);
2815
2816	/* evt_type-specific initialization, if any */
2817	switch (evt_type) {
2818	case SDEV_EVT_MEDIA_CHANGE:
2819	case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2820	case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2821	case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2822	case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2823	case SDEV_EVT_LUN_CHANGE_REPORTED:
2824	case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
 
2825	default:
2826		/* do nothing */
2827		break;
2828	}
2829
2830	return evt;
2831}
2832EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2833
2834/**
2835 * 	sdev_evt_send_simple - send asserted event to uevent thread
2836 *	@sdev: scsi_device event occurred on
2837 *	@evt_type: type of event to send
2838 *	@gfpflags: GFP flags for allocation
2839 *
2840 *	Assert scsi device event asynchronously, given an event type.
2841 */
2842void sdev_evt_send_simple(struct scsi_device *sdev,
2843			  enum scsi_device_event evt_type, gfp_t gfpflags)
2844{
2845	struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2846	if (!evt) {
2847		sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2848			    evt_type);
2849		return;
2850	}
2851
2852	sdev_evt_send(sdev, evt);
2853}
2854EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2855
2856/**
2857 *	scsi_device_quiesce - Block user issued commands.
2858 *	@sdev:	scsi device to quiesce.
2859 *
2860 *	This works by trying to transition to the SDEV_QUIESCE state
2861 *	(which must be a legal transition).  When the device is in this
2862 *	state, only special requests will be accepted, all others will
2863 *	be deferred.  Since special requests may also be requeued requests,
2864 *	a successful return doesn't guarantee the device will be 
2865 *	totally quiescent.
2866 *
2867 *	Must be called with user context, may sleep.
2868 *
2869 *	Returns zero if unsuccessful or an error if not.
2870 */
2871int
2872scsi_device_quiesce(struct scsi_device *sdev)
2873{
2874	int err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2875	if (err)
2876		return err;
2877
2878	scsi_run_queue(sdev->request_queue);
2879	while (atomic_read(&sdev->device_busy)) {
2880		msleep_interruptible(200);
2881		scsi_run_queue(sdev->request_queue);
2882	}
2883	return 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2884}
2885EXPORT_SYMBOL(scsi_device_quiesce);
2886
2887/**
2888 *	scsi_device_resume - Restart user issued commands to a quiesced device.
2889 *	@sdev:	scsi device to resume.
2890 *
2891 *	Moves the device from quiesced back to running and restarts the
2892 *	queues.
2893 *
2894 *	Must be called with user context, may sleep.
2895 */
2896void scsi_device_resume(struct scsi_device *sdev)
2897{
2898	/* check if the device state was mutated prior to resume, and if
2899	 * so assume the state is being managed elsewhere (for example
2900	 * device deleted during suspend)
2901	 */
2902	if (sdev->sdev_state != SDEV_QUIESCE ||
2903	    scsi_device_set_state(sdev, SDEV_RUNNING))
2904		return;
2905	scsi_run_queue(sdev->request_queue);
 
 
 
 
2906}
2907EXPORT_SYMBOL(scsi_device_resume);
2908
2909static void
2910device_quiesce_fn(struct scsi_device *sdev, void *data)
2911{
2912	scsi_device_quiesce(sdev);
2913}
2914
2915void
2916scsi_target_quiesce(struct scsi_target *starget)
2917{
2918	starget_for_each_device(starget, NULL, device_quiesce_fn);
2919}
2920EXPORT_SYMBOL(scsi_target_quiesce);
2921
2922static void
2923device_resume_fn(struct scsi_device *sdev, void *data)
2924{
2925	scsi_device_resume(sdev);
2926}
2927
2928void
2929scsi_target_resume(struct scsi_target *starget)
2930{
2931	starget_for_each_device(starget, NULL, device_resume_fn);
2932}
2933EXPORT_SYMBOL(scsi_target_resume);
2934
2935/**
2936 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state
2937 * @sdev:	device to block
2938 *
2939 * Block request made by scsi lld's to temporarily stop all
2940 * scsi commands on the specified device.  Called from interrupt
2941 * or normal process context.
2942 *
2943 * Returns zero if successful or error if not
2944 *
2945 * Notes:       
2946 *	This routine transitions the device to the SDEV_BLOCK state
2947 *	(which must be a legal transition).  When the device is in this
2948 *	state, all commands are deferred until the scsi lld reenables
2949 *	the device with scsi_device_unblock or device_block_tmo fires.
2950 */
2951int
2952scsi_internal_device_block(struct scsi_device *sdev)
2953{
2954	struct request_queue *q = sdev->request_queue;
2955	unsigned long flags;
2956	int err = 0;
2957
2958	err = scsi_device_set_state(sdev, SDEV_BLOCK);
2959	if (err) {
2960		err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2961
2962		if (err)
2963			return err;
2964	}
2965
2966	/* 
2967	 * The device has transitioned to SDEV_BLOCK.  Stop the
2968	 * block layer from calling the midlayer with this device's
2969	 * request queue. 
2970	 */
2971	if (q->mq_ops) {
2972		blk_mq_stop_hw_queues(q);
2973	} else {
2974		spin_lock_irqsave(q->queue_lock, flags);
2975		blk_stop_queue(q);
2976		spin_unlock_irqrestore(q->queue_lock, flags);
2977	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2978
2979	return 0;
2980}
2981EXPORT_SYMBOL_GPL(scsi_internal_device_block);
2982 
2983/**
2984 * scsi_internal_device_unblock - resume a device after a block request
2985 * @sdev:	device to resume
2986 * @new_state:	state to set devices to after unblocking
 
 
 
 
 
2987 *
2988 * Called by scsi lld's or the midlayer to restart the device queue
2989 * for the previously suspended scsi device.  Called from interrupt or
2990 * normal process context.
2991 *
2992 * Returns zero if successful or error if not.
2993 *
2994 * Notes:       
2995 *	This routine transitions the device to the SDEV_RUNNING state
2996 *	or to one of the offline states (which must be a legal transition)
2997 *	allowing the midlayer to goose the queue for this device.
2998 */
2999int
3000scsi_internal_device_unblock(struct scsi_device *sdev,
3001			     enum scsi_device_state new_state)
3002{
3003	struct request_queue *q = sdev->request_queue; 
3004	unsigned long flags;
 
 
 
 
 
3005
3006	/*
3007	 * Try to transition the scsi device to SDEV_RUNNING or one of the
3008	 * offlined states and goose the device queue if successful.
3009	 */
3010	if ((sdev->sdev_state == SDEV_BLOCK) ||
3011	    (sdev->sdev_state == SDEV_TRANSPORT_OFFLINE))
 
3012		sdev->sdev_state = new_state;
3013	else if (sdev->sdev_state == SDEV_CREATED_BLOCK) {
 
3014		if (new_state == SDEV_TRANSPORT_OFFLINE ||
3015		    new_state == SDEV_OFFLINE)
3016			sdev->sdev_state = new_state;
3017		else
3018			sdev->sdev_state = SDEV_CREATED;
3019	} else if (sdev->sdev_state != SDEV_CANCEL &&
3020		 sdev->sdev_state != SDEV_OFFLINE)
 
 
 
3021		return -EINVAL;
3022
3023	if (q->mq_ops) {
3024		blk_mq_start_stopped_hw_queues(q, false);
3025	} else {
3026		spin_lock_irqsave(q->queue_lock, flags);
3027		blk_start_queue(q);
3028		spin_unlock_irqrestore(q->queue_lock, flags);
3029	}
 
3030
3031	return 0;
3032}
3033EXPORT_SYMBOL_GPL(scsi_internal_device_unblock);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3034
3035static void
3036device_block(struct scsi_device *sdev, void *data)
3037{
3038	scsi_internal_device_block(sdev);
 
 
 
 
 
3039}
3040
3041static int
3042target_block(struct device *dev, void *data)
3043{
3044	if (scsi_is_target_device(dev))
3045		starget_for_each_device(to_scsi_target(dev), NULL,
3046					device_block);
3047	return 0;
3048}
3049
3050void
3051scsi_target_block(struct device *dev)
3052{
3053	if (scsi_is_target_device(dev))
3054		starget_for_each_device(to_scsi_target(dev), NULL,
3055					device_block);
3056	else
3057		device_for_each_child(dev, NULL, target_block);
3058}
3059EXPORT_SYMBOL_GPL(scsi_target_block);
3060
3061static void
3062device_unblock(struct scsi_device *sdev, void *data)
3063{
3064	scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
3065}
3066
3067static int
3068target_unblock(struct device *dev, void *data)
3069{
3070	if (scsi_is_target_device(dev))
3071		starget_for_each_device(to_scsi_target(dev), data,
3072					device_unblock);
3073	return 0;
3074}
3075
3076void
3077scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
3078{
3079	if (scsi_is_target_device(dev))
3080		starget_for_each_device(to_scsi_target(dev), &new_state,
3081					device_unblock);
3082	else
3083		device_for_each_child(dev, &new_state, target_unblock);
3084}
3085EXPORT_SYMBOL_GPL(scsi_target_unblock);
3086
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3087/**
3088 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
3089 * @sgl:	scatter-gather list
3090 * @sg_count:	number of segments in sg
3091 * @offset:	offset in bytes into sg, on return offset into the mapped area
3092 * @len:	bytes to map, on return number of bytes mapped
3093 *
3094 * Returns virtual address of the start of the mapped page
3095 */
3096void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
3097			  size_t *offset, size_t *len)
3098{
3099	int i;
3100	size_t sg_len = 0, len_complete = 0;
3101	struct scatterlist *sg;
3102	struct page *page;
3103
3104	WARN_ON(!irqs_disabled());
3105
3106	for_each_sg(sgl, sg, sg_count, i) {
3107		len_complete = sg_len; /* Complete sg-entries */
3108		sg_len += sg->length;
3109		if (sg_len > *offset)
3110			break;
3111	}
3112
3113	if (unlikely(i == sg_count)) {
3114		printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
3115			"elements %d\n",
3116		       __func__, sg_len, *offset, sg_count);
3117		WARN_ON(1);
3118		return NULL;
3119	}
3120
3121	/* Offset starting from the beginning of first page in this sg-entry */
3122	*offset = *offset - len_complete + sg->offset;
3123
3124	/* Assumption: contiguous pages can be accessed as "page + i" */
3125	page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
3126	*offset &= ~PAGE_MASK;
3127
3128	/* Bytes in this sg-entry from *offset to the end of the page */
3129	sg_len = PAGE_SIZE - *offset;
3130	if (*len > sg_len)
3131		*len = sg_len;
3132
3133	return kmap_atomic(page);
3134}
3135EXPORT_SYMBOL(scsi_kmap_atomic_sg);
3136
3137/**
3138 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
3139 * @virt:	virtual address to be unmapped
3140 */
3141void scsi_kunmap_atomic_sg(void *virt)
3142{
3143	kunmap_atomic(virt);
3144}
3145EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
3146
3147void sdev_disable_disk_events(struct scsi_device *sdev)
3148{
3149	atomic_inc(&sdev->disk_events_disable_depth);
3150}
3151EXPORT_SYMBOL(sdev_disable_disk_events);
3152
3153void sdev_enable_disk_events(struct scsi_device *sdev)
3154{
3155	if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0))
3156		return;
3157	atomic_dec(&sdev->disk_events_disable_depth);
3158}
3159EXPORT_SYMBOL(sdev_enable_disk_events);
3160
3161/**
3162 * scsi_vpd_lun_id - return a unique device identification
3163 * @sdev: SCSI device
3164 * @id:   buffer for the identification
3165 * @id_len:  length of the buffer
3166 *
3167 * Copies a unique device identification into @id based
3168 * on the information in the VPD page 0x83 of the device.
3169 * The string will be formatted as a SCSI name string.
3170 *
3171 * Returns the length of the identification or error on failure.
3172 * If the identifier is longer than the supplied buffer the actual
3173 * identifier length is returned and the buffer is not zero-padded.
3174 */
3175int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len)
3176{
3177	u8 cur_id_type = 0xff;
3178	u8 cur_id_size = 0;
3179	unsigned char *d, *cur_id_str;
3180	unsigned char __rcu *vpd_pg83;
3181	int id_size = -EINVAL;
3182
3183	rcu_read_lock();
3184	vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3185	if (!vpd_pg83) {
3186		rcu_read_unlock();
3187		return -ENXIO;
3188	}
3189
3190	/*
3191	 * Look for the correct descriptor.
3192	 * Order of preference for lun descriptor:
3193	 * - SCSI name string
3194	 * - NAA IEEE Registered Extended
3195	 * - EUI-64 based 16-byte
3196	 * - EUI-64 based 12-byte
3197	 * - NAA IEEE Registered
3198	 * - NAA IEEE Extended
 
3199	 * as longer descriptors reduce the likelyhood
3200	 * of identification clashes.
3201	 */
3202
3203	/* The id string must be at least 20 bytes + terminating NULL byte */
3204	if (id_len < 21) {
3205		rcu_read_unlock();
3206		return -EINVAL;
3207	}
3208
3209	memset(id, 0, id_len);
3210	d = vpd_pg83 + 4;
3211	while (d < vpd_pg83 + sdev->vpd_pg83_len) {
3212		/* Skip designators not referring to the LUN */
3213		if ((d[1] & 0x30) != 0x00)
3214			goto next_desig;
3215
3216		switch (d[1] & 0xf) {
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3217		case 0x2:
3218			/* EUI-64 */
3219			if (cur_id_size > d[3])
3220				break;
3221			/* Prefer NAA IEEE Registered Extended */
3222			if (cur_id_type == 0x3 &&
3223			    cur_id_size == d[3])
3224				break;
3225			cur_id_size = d[3];
3226			cur_id_str = d + 4;
3227			cur_id_type = d[1] & 0xf;
3228			switch (cur_id_size) {
3229			case 8:
3230				id_size = snprintf(id, id_len,
3231						   "eui.%8phN",
3232						   cur_id_str);
3233				break;
3234			case 12:
3235				id_size = snprintf(id, id_len,
3236						   "eui.%12phN",
3237						   cur_id_str);
3238				break;
3239			case 16:
3240				id_size = snprintf(id, id_len,
3241						   "eui.%16phN",
3242						   cur_id_str);
3243				break;
3244			default:
3245				cur_id_size = 0;
3246				break;
3247			}
3248			break;
3249		case 0x3:
3250			/* NAA */
3251			if (cur_id_size > d[3])
3252				break;
3253			cur_id_size = d[3];
3254			cur_id_str = d + 4;
3255			cur_id_type = d[1] & 0xf;
3256			switch (cur_id_size) {
3257			case 8:
3258				id_size = snprintf(id, id_len,
3259						   "naa.%8phN",
3260						   cur_id_str);
3261				break;
3262			case 16:
3263				id_size = snprintf(id, id_len,
3264						   "naa.%16phN",
3265						   cur_id_str);
3266				break;
3267			default:
3268				cur_id_size = 0;
3269				break;
3270			}
3271			break;
3272		case 0x8:
3273			/* SCSI name string */
3274			if (cur_id_size + 4 > d[3])
3275				break;
3276			/* Prefer others for truncated descriptor */
3277			if (cur_id_size && d[3] > id_len)
3278				break;
3279			cur_id_size = id_size = d[3];
3280			cur_id_str = d + 4;
3281			cur_id_type = d[1] & 0xf;
3282			if (cur_id_size >= id_len)
3283				cur_id_size = id_len - 1;
3284			memcpy(id, cur_id_str, cur_id_size);
3285			/* Decrease priority for truncated descriptor */
3286			if (cur_id_size != id_size)
3287				cur_id_size = 6;
3288			break;
3289		default:
3290			break;
3291		}
3292next_desig:
3293		d += d[3] + 4;
3294	}
3295	rcu_read_unlock();
3296
3297	return id_size;
3298}
3299EXPORT_SYMBOL(scsi_vpd_lun_id);
3300
3301/*
3302 * scsi_vpd_tpg_id - return a target port group identifier
3303 * @sdev: SCSI device
3304 *
3305 * Returns the Target Port Group identifier from the information
3306 * froom VPD page 0x83 of the device.
3307 *
3308 * Returns the identifier or error on failure.
3309 */
3310int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id)
3311{
3312	unsigned char *d;
3313	unsigned char __rcu *vpd_pg83;
3314	int group_id = -EAGAIN, rel_port = -1;
3315
3316	rcu_read_lock();
3317	vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3318	if (!vpd_pg83) {
3319		rcu_read_unlock();
3320		return -ENXIO;
3321	}
3322
3323	d = sdev->vpd_pg83 + 4;
3324	while (d < sdev->vpd_pg83 + sdev->vpd_pg83_len) {
3325		switch (d[1] & 0xf) {
3326		case 0x4:
3327			/* Relative target port */
3328			rel_port = get_unaligned_be16(&d[6]);
3329			break;
3330		case 0x5:
3331			/* Target port group */
3332			group_id = get_unaligned_be16(&d[6]);
3333			break;
3334		default:
3335			break;
3336		}
3337		d += d[3] + 4;
3338	}
3339	rcu_read_unlock();
3340
3341	if (group_id >= 0 && rel_id && rel_port != -1)
3342		*rel_id = rel_port;
3343
3344	return group_id;
3345}
3346EXPORT_SYMBOL(scsi_vpd_tpg_id);