2 * Copyright (C) 1999 Eric Youngdale
3 * Copyright (C) 2014 Christoph Hellwig
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.
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/init.h>
18 #include <linux/pci.h>
19 #include <linux/delay.h>
20 #include <linux/hardirq.h>
21 #include <linux/scatterlist.h>
22 #include <linux/blk-mq.h>
23 #include <linux/ratelimit.h>
24 #include <asm/unaligned.h>
26 #include <scsi/scsi.h>
27 #include <scsi/scsi_cmnd.h>
28 #include <scsi/scsi_dbg.h>
29 #include <scsi/scsi_device.h>
30 #include <scsi/scsi_driver.h>
31 #include <scsi/scsi_eh.h>
32 #include <scsi/scsi_host.h>
33 #include <scsi/scsi_transport.h> /* __scsi_init_queue() */
34 #include <scsi/scsi_dh.h>
36 #include <trace/events/scsi.h>
38 #include "scsi_debugfs.h"
39 #include "scsi_priv.h"
40 #include "scsi_logging.h"
42 static struct kmem_cache *scsi_sdb_cache;
43 static struct kmem_cache *scsi_sense_cache;
44 static struct kmem_cache *scsi_sense_isadma_cache;
45 static DEFINE_MUTEX(scsi_sense_cache_mutex);
47 static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd);
49 static inline struct kmem_cache *
50 scsi_select_sense_cache(bool unchecked_isa_dma)
52 return unchecked_isa_dma ? scsi_sense_isadma_cache : scsi_sense_cache;
55 static void scsi_free_sense_buffer(bool unchecked_isa_dma,
56 unsigned char *sense_buffer)
58 kmem_cache_free(scsi_select_sense_cache(unchecked_isa_dma),
62 static unsigned char *scsi_alloc_sense_buffer(bool unchecked_isa_dma,
63 gfp_t gfp_mask, int numa_node)
65 return kmem_cache_alloc_node(scsi_select_sense_cache(unchecked_isa_dma),
69 int scsi_init_sense_cache(struct Scsi_Host *shost)
71 struct kmem_cache *cache;
74 cache = scsi_select_sense_cache(shost->unchecked_isa_dma);
78 mutex_lock(&scsi_sense_cache_mutex);
79 if (shost->unchecked_isa_dma) {
80 scsi_sense_isadma_cache =
81 kmem_cache_create("scsi_sense_cache(DMA)",
82 SCSI_SENSE_BUFFERSIZE, 0,
83 SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA, NULL);
84 if (!scsi_sense_isadma_cache)
88 kmem_cache_create_usercopy("scsi_sense_cache",
89 SCSI_SENSE_BUFFERSIZE, 0, SLAB_HWCACHE_ALIGN,
90 0, SCSI_SENSE_BUFFERSIZE, NULL);
91 if (!scsi_sense_cache)
95 mutex_unlock(&scsi_sense_cache_mutex);
100 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
101 * not change behaviour from the previous unplug mechanism, experimentation
102 * may prove this needs changing.
104 #define SCSI_QUEUE_DELAY 3
107 scsi_set_blocked(struct scsi_cmnd *cmd, int reason)
109 struct Scsi_Host *host = cmd->device->host;
110 struct scsi_device *device = cmd->device;
111 struct scsi_target *starget = scsi_target(device);
114 * Set the appropriate busy bit for the device/host.
116 * If the host/device isn't busy, assume that something actually
117 * completed, and that we should be able to queue a command now.
119 * Note that the prior mid-layer assumption that any host could
120 * always queue at least one command is now broken. The mid-layer
121 * will implement a user specifiable stall (see
122 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
123 * if a command is requeued with no other commands outstanding
124 * either for the device or for the host.
127 case SCSI_MLQUEUE_HOST_BUSY:
128 atomic_set(&host->host_blocked, host->max_host_blocked);
130 case SCSI_MLQUEUE_DEVICE_BUSY:
131 case SCSI_MLQUEUE_EH_RETRY:
132 atomic_set(&device->device_blocked,
133 device->max_device_blocked);
135 case SCSI_MLQUEUE_TARGET_BUSY:
136 atomic_set(&starget->target_blocked,
137 starget->max_target_blocked);
142 static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd)
144 struct scsi_device *sdev = cmd->device;
146 if (cmd->request->rq_flags & RQF_DONTPREP) {
147 cmd->request->rq_flags &= ~RQF_DONTPREP;
148 scsi_mq_uninit_cmd(cmd);
152 blk_mq_requeue_request(cmd->request, true);
153 put_device(&sdev->sdev_gendev);
157 * __scsi_queue_insert - private queue insertion
158 * @cmd: The SCSI command being requeued
159 * @reason: The reason for the requeue
160 * @unbusy: Whether the queue should be unbusied
162 * This is a private queue insertion. The public interface
163 * scsi_queue_insert() always assumes the queue should be unbusied
164 * because it's always called before the completion. This function is
165 * for a requeue after completion, which should only occur in this
168 static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy)
170 struct scsi_device *device = cmd->device;
172 SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd,
173 "Inserting command %p into mlqueue\n", cmd));
175 scsi_set_blocked(cmd, reason);
178 * Decrement the counters, since these commands are no longer
179 * active on the host/device.
182 scsi_device_unbusy(device);
185 * Requeue this command. It will go before all other commands
186 * that are already in the queue. Schedule requeue work under
187 * lock such that the kblockd_schedule_work() call happens
188 * before blk_cleanup_queue() finishes.
193 * Before a SCSI command is dispatched,
194 * get_device(&sdev->sdev_gendev) is called and the host,
195 * target and device busy counters are increased. Since
196 * requeuing a request causes these actions to be repeated and
197 * since scsi_device_unbusy() has already been called,
198 * put_device(&device->sdev_gendev) must still be called. Call
199 * put_device() after blk_mq_requeue_request() to avoid that
200 * removal of the SCSI device can start before requeueing has
203 blk_mq_requeue_request(cmd->request, true);
204 put_device(&device->sdev_gendev);
208 * Function: scsi_queue_insert()
210 * Purpose: Insert a command in the midlevel queue.
212 * Arguments: cmd - command that we are adding to queue.
213 * reason - why we are inserting command to queue.
215 * Lock status: Assumed that lock is not held upon entry.
219 * Notes: We do this for one of two cases. Either the host is busy
220 * and it cannot accept any more commands for the time being,
221 * or the device returned QUEUE_FULL and can accept no more
223 * Notes: This could be called either from an interrupt context or a
224 * normal process context.
226 void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
228 __scsi_queue_insert(cmd, reason, true);
233 * __scsi_execute - insert request and wait for the result
236 * @data_direction: data direction
237 * @buffer: data buffer
238 * @bufflen: len of buffer
239 * @sense: optional sense buffer
240 * @sshdr: optional decoded sense header
241 * @timeout: request timeout in seconds
242 * @retries: number of times to retry request
243 * @flags: flags for ->cmd_flags
244 * @rq_flags: flags for ->rq_flags
245 * @resid: optional residual length
247 * Returns the scsi_cmnd result field if a command was executed, or a negative
248 * Linux error code if we didn't get that far.
250 int __scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
251 int data_direction, void *buffer, unsigned bufflen,
252 unsigned char *sense, struct scsi_sense_hdr *sshdr,
253 int timeout, int retries, u64 flags, req_flags_t rq_flags,
257 struct scsi_request *rq;
258 int ret = DRIVER_ERROR << 24;
260 req = blk_get_request(sdev->request_queue,
261 data_direction == DMA_TO_DEVICE ?
262 REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, BLK_MQ_REQ_PREEMPT);
267 if (bufflen && blk_rq_map_kern(sdev->request_queue, req,
268 buffer, bufflen, GFP_NOIO))
271 rq->cmd_len = COMMAND_SIZE(cmd[0]);
272 memcpy(rq->cmd, cmd, rq->cmd_len);
273 rq->retries = retries;
274 req->timeout = timeout;
275 req->cmd_flags |= flags;
276 req->rq_flags |= rq_flags | RQF_QUIET;
279 * head injection *required* here otherwise quiesce won't work
281 blk_execute_rq(req->q, NULL, req, 1);
284 * Some devices (USB mass-storage in particular) may transfer
285 * garbage data together with a residue indicating that the data
286 * is invalid. Prevent the garbage from being misinterpreted
287 * and prevent security leaks by zeroing out the excess data.
289 if (unlikely(rq->resid_len > 0 && rq->resid_len <= bufflen))
290 memset(buffer + (bufflen - rq->resid_len), 0, rq->resid_len);
293 *resid = rq->resid_len;
294 if (sense && rq->sense_len)
295 memcpy(sense, rq->sense, SCSI_SENSE_BUFFERSIZE);
297 scsi_normalize_sense(rq->sense, rq->sense_len, sshdr);
300 blk_put_request(req);
304 EXPORT_SYMBOL(__scsi_execute);
307 * Function: scsi_init_cmd_errh()
309 * Purpose: Initialize cmd fields related to error handling.
311 * Arguments: cmd - command that is ready to be queued.
313 * Notes: This function has the job of initializing a number of
314 * fields related to error handling. Typically this will
315 * be called once for each command, as required.
317 static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
319 scsi_set_resid(cmd, 0);
320 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
321 if (cmd->cmd_len == 0)
322 cmd->cmd_len = scsi_command_size(cmd->cmnd);
326 * Decrement the host_busy counter and wake up the error handler if necessary.
327 * Avoid as follows that the error handler is not woken up if shost->host_busy
328 * == shost->host_failed: use call_rcu() in scsi_eh_scmd_add() in combination
329 * with an RCU read lock in this function to ensure that this function in its
330 * entirety either finishes before scsi_eh_scmd_add() increases the
331 * host_failed counter or that it notices the shost state change made by
332 * scsi_eh_scmd_add().
334 static void scsi_dec_host_busy(struct Scsi_Host *shost)
339 atomic_dec(&shost->host_busy);
340 if (unlikely(scsi_host_in_recovery(shost))) {
341 spin_lock_irqsave(shost->host_lock, flags);
342 if (shost->host_failed || shost->host_eh_scheduled)
343 scsi_eh_wakeup(shost);
344 spin_unlock_irqrestore(shost->host_lock, flags);
349 void scsi_device_unbusy(struct scsi_device *sdev)
351 struct Scsi_Host *shost = sdev->host;
352 struct scsi_target *starget = scsi_target(sdev);
354 scsi_dec_host_busy(shost);
356 if (starget->can_queue > 0)
357 atomic_dec(&starget->target_busy);
359 atomic_dec(&sdev->device_busy);
362 static void scsi_kick_queue(struct request_queue *q)
364 blk_mq_run_hw_queues(q, false);
368 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
369 * and call blk_run_queue for all the scsi_devices on the target -
370 * including current_sdev first.
372 * Called with *no* scsi locks held.
374 static void scsi_single_lun_run(struct scsi_device *current_sdev)
376 struct Scsi_Host *shost = current_sdev->host;
377 struct scsi_device *sdev, *tmp;
378 struct scsi_target *starget = scsi_target(current_sdev);
381 spin_lock_irqsave(shost->host_lock, flags);
382 starget->starget_sdev_user = NULL;
383 spin_unlock_irqrestore(shost->host_lock, flags);
386 * Call blk_run_queue for all LUNs on the target, starting with
387 * current_sdev. We race with others (to set starget_sdev_user),
388 * but in most cases, we will be first. Ideally, each LU on the
389 * target would get some limited time or requests on the target.
391 scsi_kick_queue(current_sdev->request_queue);
393 spin_lock_irqsave(shost->host_lock, flags);
394 if (starget->starget_sdev_user)
396 list_for_each_entry_safe(sdev, tmp, &starget->devices,
397 same_target_siblings) {
398 if (sdev == current_sdev)
400 if (scsi_device_get(sdev))
403 spin_unlock_irqrestore(shost->host_lock, flags);
404 scsi_kick_queue(sdev->request_queue);
405 spin_lock_irqsave(shost->host_lock, flags);
407 scsi_device_put(sdev);
410 spin_unlock_irqrestore(shost->host_lock, flags);
413 static inline bool scsi_device_is_busy(struct scsi_device *sdev)
415 if (atomic_read(&sdev->device_busy) >= sdev->queue_depth)
417 if (atomic_read(&sdev->device_blocked) > 0)
422 static inline bool scsi_target_is_busy(struct scsi_target *starget)
424 if (starget->can_queue > 0) {
425 if (atomic_read(&starget->target_busy) >= starget->can_queue)
427 if (atomic_read(&starget->target_blocked) > 0)
433 static inline bool scsi_host_is_busy(struct Scsi_Host *shost)
435 if (shost->can_queue > 0 &&
436 atomic_read(&shost->host_busy) >= shost->can_queue)
438 if (atomic_read(&shost->host_blocked) > 0)
440 if (shost->host_self_blocked)
445 static void scsi_starved_list_run(struct Scsi_Host *shost)
447 LIST_HEAD(starved_list);
448 struct scsi_device *sdev;
451 spin_lock_irqsave(shost->host_lock, flags);
452 list_splice_init(&shost->starved_list, &starved_list);
454 while (!list_empty(&starved_list)) {
455 struct request_queue *slq;
458 * As long as shost is accepting commands and we have
459 * starved queues, call blk_run_queue. scsi_request_fn
460 * drops the queue_lock and can add us back to the
463 * host_lock protects the starved_list and starved_entry.
464 * scsi_request_fn must get the host_lock before checking
465 * or modifying starved_list or starved_entry.
467 if (scsi_host_is_busy(shost))
470 sdev = list_entry(starved_list.next,
471 struct scsi_device, starved_entry);
472 list_del_init(&sdev->starved_entry);
473 if (scsi_target_is_busy(scsi_target(sdev))) {
474 list_move_tail(&sdev->starved_entry,
475 &shost->starved_list);
480 * Once we drop the host lock, a racing scsi_remove_device()
481 * call may remove the sdev from the starved list and destroy
482 * it and the queue. Mitigate by taking a reference to the
483 * queue and never touching the sdev again after we drop the
484 * host lock. Note: if __scsi_remove_device() invokes
485 * blk_cleanup_queue() before the queue is run from this
486 * function then blk_run_queue() will return immediately since
487 * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING.
489 slq = sdev->request_queue;
490 if (!blk_get_queue(slq))
492 spin_unlock_irqrestore(shost->host_lock, flags);
494 scsi_kick_queue(slq);
497 spin_lock_irqsave(shost->host_lock, flags);
499 /* put any unprocessed entries back */
500 list_splice(&starved_list, &shost->starved_list);
501 spin_unlock_irqrestore(shost->host_lock, flags);
505 * Function: scsi_run_queue()
507 * Purpose: Select a proper request queue to serve next
509 * Arguments: q - last request's queue
513 * Notes: The previous command was completely finished, start
514 * a new one if possible.
516 static void scsi_run_queue(struct request_queue *q)
518 struct scsi_device *sdev = q->queuedata;
520 if (scsi_target(sdev)->single_lun)
521 scsi_single_lun_run(sdev);
522 if (!list_empty(&sdev->host->starved_list))
523 scsi_starved_list_run(sdev->host);
525 blk_mq_run_hw_queues(q, false);
528 void scsi_requeue_run_queue(struct work_struct *work)
530 struct scsi_device *sdev;
531 struct request_queue *q;
533 sdev = container_of(work, struct scsi_device, requeue_work);
534 q = sdev->request_queue;
538 void scsi_run_host_queues(struct Scsi_Host *shost)
540 struct scsi_device *sdev;
542 shost_for_each_device(sdev, shost)
543 scsi_run_queue(sdev->request_queue);
546 static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
548 if (!blk_rq_is_passthrough(cmd->request)) {
549 struct scsi_driver *drv = scsi_cmd_to_driver(cmd);
551 if (drv->uninit_command)
552 drv->uninit_command(cmd);
556 static void scsi_mq_free_sgtables(struct scsi_cmnd *cmd)
558 if (cmd->sdb.table.nents)
559 sg_free_table_chained(&cmd->sdb.table, true);
560 if (scsi_prot_sg_count(cmd))
561 sg_free_table_chained(&cmd->prot_sdb->table, true);
564 static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
566 scsi_mq_free_sgtables(cmd);
567 scsi_uninit_cmd(cmd);
568 scsi_del_cmd_from_list(cmd);
571 /* Returns false when no more bytes to process, true if there are more */
572 static bool scsi_end_request(struct request *req, blk_status_t error,
575 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
576 struct scsi_device *sdev = cmd->device;
577 struct request_queue *q = sdev->request_queue;
579 if (blk_update_request(req, error, bytes))
582 if (blk_queue_add_random(q))
583 add_disk_randomness(req->rq_disk);
585 if (!blk_rq_is_scsi(req)) {
586 WARN_ON_ONCE(!(cmd->flags & SCMD_INITIALIZED));
587 cmd->flags &= ~SCMD_INITIALIZED;
591 * Calling rcu_barrier() is not necessary here because the
592 * SCSI error handler guarantees that the function called by
593 * call_rcu() has been called before scsi_end_request() is
596 destroy_rcu_head(&cmd->rcu);
599 * In the MQ case the command gets freed by __blk_mq_end_request,
600 * so we have to do all cleanup that depends on it earlier.
602 * We also can't kick the queues from irq context, so we
603 * will have to defer it to a workqueue.
605 scsi_mq_uninit_cmd(cmd);
608 * queue is still alive, so grab the ref for preventing it
609 * from being cleaned up during running queue.
611 percpu_ref_get(&q->q_usage_counter);
613 __blk_mq_end_request(req, error);
615 if (scsi_target(sdev)->single_lun ||
616 !list_empty(&sdev->host->starved_list))
617 kblockd_schedule_work(&sdev->requeue_work);
619 blk_mq_run_hw_queues(q, true);
621 percpu_ref_put(&q->q_usage_counter);
622 put_device(&sdev->sdev_gendev);
627 * scsi_result_to_blk_status - translate a SCSI result code into blk_status_t
629 * @result: scsi error code
631 * Translate a SCSI result code into a blk_status_t value. May reset the host
632 * byte of @cmd->result.
634 static blk_status_t scsi_result_to_blk_status(struct scsi_cmnd *cmd, int result)
636 switch (host_byte(result)) {
639 * Also check the other bytes than the status byte in result
640 * to handle the case when a SCSI LLD sets result to
641 * DRIVER_SENSE << 24 without setting SAM_STAT_CHECK_CONDITION.
643 if (scsi_status_is_good(result) && (result & ~0xff) == 0)
645 return BLK_STS_IOERR;
646 case DID_TRANSPORT_FAILFAST:
647 return BLK_STS_TRANSPORT;
648 case DID_TARGET_FAILURE:
649 set_host_byte(cmd, DID_OK);
650 return BLK_STS_TARGET;
651 case DID_NEXUS_FAILURE:
652 set_host_byte(cmd, DID_OK);
653 return BLK_STS_NEXUS;
654 case DID_ALLOC_FAILURE:
655 set_host_byte(cmd, DID_OK);
656 return BLK_STS_NOSPC;
657 case DID_MEDIUM_ERROR:
658 set_host_byte(cmd, DID_OK);
659 return BLK_STS_MEDIUM;
661 return BLK_STS_IOERR;
665 /* Helper for scsi_io_completion() when "reprep" action required. */
666 static void scsi_io_completion_reprep(struct scsi_cmnd *cmd,
667 struct request_queue *q)
669 /* A new command will be prepared and issued. */
670 scsi_mq_requeue_cmd(cmd);
673 /* Helper for scsi_io_completion() when special action required. */
674 static void scsi_io_completion_action(struct scsi_cmnd *cmd, int result)
676 struct request_queue *q = cmd->device->request_queue;
677 struct request *req = cmd->request;
679 enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,
680 ACTION_DELAYED_RETRY} action;
681 unsigned long wait_for = (cmd->allowed + 1) * req->timeout;
682 struct scsi_sense_hdr sshdr;
684 bool sense_current = true; /* false implies "deferred sense" */
685 blk_status_t blk_stat;
687 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
689 sense_current = !scsi_sense_is_deferred(&sshdr);
691 blk_stat = scsi_result_to_blk_status(cmd, result);
693 if (host_byte(result) == DID_RESET) {
694 /* Third party bus reset or reset for error recovery
695 * reasons. Just retry the command and see what
698 action = ACTION_RETRY;
699 } else if (sense_valid && sense_current) {
700 switch (sshdr.sense_key) {
702 if (cmd->device->removable) {
703 /* Detected disc change. Set a bit
704 * and quietly refuse further access.
706 cmd->device->changed = 1;
707 action = ACTION_FAIL;
709 /* Must have been a power glitch, or a
710 * bus reset. Could not have been a
711 * media change, so we just retry the
712 * command and see what happens.
714 action = ACTION_RETRY;
717 case ILLEGAL_REQUEST:
718 /* If we had an ILLEGAL REQUEST returned, then
719 * we may have performed an unsupported
720 * command. The only thing this should be
721 * would be a ten byte read where only a six
722 * byte read was supported. Also, on a system
723 * where READ CAPACITY failed, we may have
724 * read past the end of the disk.
726 if ((cmd->device->use_10_for_rw &&
727 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
728 (cmd->cmnd[0] == READ_10 ||
729 cmd->cmnd[0] == WRITE_10)) {
730 /* This will issue a new 6-byte command. */
731 cmd->device->use_10_for_rw = 0;
732 action = ACTION_REPREP;
733 } else if (sshdr.asc == 0x10) /* DIX */ {
734 action = ACTION_FAIL;
735 blk_stat = BLK_STS_PROTECTION;
736 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
737 } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
738 action = ACTION_FAIL;
739 blk_stat = BLK_STS_TARGET;
741 action = ACTION_FAIL;
743 case ABORTED_COMMAND:
744 action = ACTION_FAIL;
745 if (sshdr.asc == 0x10) /* DIF */
746 blk_stat = BLK_STS_PROTECTION;
749 /* If the device is in the process of becoming
750 * ready, or has a temporary blockage, retry.
752 if (sshdr.asc == 0x04) {
753 switch (sshdr.ascq) {
754 case 0x01: /* becoming ready */
755 case 0x04: /* format in progress */
756 case 0x05: /* rebuild in progress */
757 case 0x06: /* recalculation in progress */
758 case 0x07: /* operation in progress */
759 case 0x08: /* Long write in progress */
760 case 0x09: /* self test in progress */
761 case 0x14: /* space allocation in progress */
762 case 0x1a: /* start stop unit in progress */
763 case 0x1b: /* sanitize in progress */
764 case 0x1d: /* configuration in progress */
765 case 0x24: /* depopulation in progress */
766 action = ACTION_DELAYED_RETRY;
769 action = ACTION_FAIL;
773 action = ACTION_FAIL;
775 case VOLUME_OVERFLOW:
776 /* See SSC3rXX or current. */
777 action = ACTION_FAIL;
780 action = ACTION_FAIL;
784 action = ACTION_FAIL;
786 if (action != ACTION_FAIL &&
787 time_before(cmd->jiffies_at_alloc + wait_for, jiffies))
788 action = ACTION_FAIL;
792 /* Give up and fail the remainder of the request */
793 if (!(req->rq_flags & RQF_QUIET)) {
794 static DEFINE_RATELIMIT_STATE(_rs,
795 DEFAULT_RATELIMIT_INTERVAL,
796 DEFAULT_RATELIMIT_BURST);
798 if (unlikely(scsi_logging_level))
800 SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
801 SCSI_LOG_MLCOMPLETE_BITS);
804 * if logging is enabled the failure will be printed
805 * in scsi_log_completion(), so avoid duplicate messages
807 if (!level && __ratelimit(&_rs)) {
808 scsi_print_result(cmd, NULL, FAILED);
809 if (driver_byte(result) == DRIVER_SENSE)
810 scsi_print_sense(cmd);
811 scsi_print_command(cmd);
814 if (!scsi_end_request(req, blk_stat, blk_rq_err_bytes(req)))
818 scsi_io_completion_reprep(cmd, q);
821 /* Retry the same command immediately */
822 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, false);
824 case ACTION_DELAYED_RETRY:
825 /* Retry the same command after a delay */
826 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, false);
832 * Helper for scsi_io_completion() when cmd->result is non-zero. Returns a
833 * new result that may suppress further error checking. Also modifies
834 * *blk_statp in some cases.
836 static int scsi_io_completion_nz_result(struct scsi_cmnd *cmd, int result,
837 blk_status_t *blk_statp)
840 bool sense_current = true; /* false implies "deferred sense" */
841 struct request *req = cmd->request;
842 struct scsi_sense_hdr sshdr;
844 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
846 sense_current = !scsi_sense_is_deferred(&sshdr);
848 if (blk_rq_is_passthrough(req)) {
851 * SG_IO wants current and deferred errors
853 scsi_req(req)->sense_len =
854 min(8 + cmd->sense_buffer[7],
855 SCSI_SENSE_BUFFERSIZE);
858 *blk_statp = scsi_result_to_blk_status(cmd, result);
859 } else if (blk_rq_bytes(req) == 0 && sense_current) {
861 * Flush commands do not transfers any data, and thus cannot use
862 * good_bytes != blk_rq_bytes(req) as the signal for an error.
863 * This sets *blk_statp explicitly for the problem case.
865 *blk_statp = scsi_result_to_blk_status(cmd, result);
868 * Recovered errors need reporting, but they're always treated as
869 * success, so fiddle the result code here. For passthrough requests
870 * we already took a copy of the original into sreq->result which
871 * is what gets returned to the user
873 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
874 bool do_print = true;
876 * if ATA PASS-THROUGH INFORMATION AVAILABLE [0x0, 0x1d]
877 * skip print since caller wants ATA registers. Only occurs
878 * on SCSI ATA PASS_THROUGH commands when CK_COND=1
880 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
882 else if (req->rq_flags & RQF_QUIET)
885 scsi_print_sense(cmd);
887 /* for passthrough, *blk_statp may be set */
888 *blk_statp = BLK_STS_OK;
891 * Another corner case: the SCSI status byte is non-zero but 'good'.
892 * Example: PRE-FETCH command returns SAM_STAT_CONDITION_MET when
893 * it is able to fit nominated LBs in its cache (and SAM_STAT_GOOD
894 * if it can't fit). Treat SAM_STAT_CONDITION_MET and the related
895 * intermediate statuses (both obsolete in SAM-4) as good.
897 if (status_byte(result) && scsi_status_is_good(result)) {
899 *blk_statp = BLK_STS_OK;
905 * Function: scsi_io_completion()
907 * Purpose: Completion processing for block device I/O requests.
909 * Arguments: cmd - command that is finished.
911 * Lock status: Assumed that no lock is held upon entry.
915 * Notes: We will finish off the specified number of sectors. If we
916 * are done, the command block will be released and the queue
917 * function will be goosed. If we are not done then we have to
918 * figure out what to do next:
920 * a) We can call scsi_requeue_command(). The request
921 * will be unprepared and put back on the queue. Then
922 * a new command will be created for it. This should
923 * be used if we made forward progress, or if we want
924 * to switch from READ(10) to READ(6) for example.
926 * b) We can call __scsi_queue_insert(). The request will
927 * be put back on the queue and retried using the same
928 * command as before, possibly after a delay.
930 * c) We can call scsi_end_request() with blk_stat other than
931 * BLK_STS_OK, to fail the remainder of the request.
933 void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
935 int result = cmd->result;
936 struct request_queue *q = cmd->device->request_queue;
937 struct request *req = cmd->request;
938 blk_status_t blk_stat = BLK_STS_OK;
940 if (unlikely(result)) /* a nz result may or may not be an error */
941 result = scsi_io_completion_nz_result(cmd, result, &blk_stat);
943 if (unlikely(blk_rq_is_passthrough(req))) {
945 * scsi_result_to_blk_status may have reset the host_byte
947 scsi_req(req)->result = cmd->result;
951 * Next deal with any sectors which we were able to correctly
954 SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd,
955 "%u sectors total, %d bytes done.\n",
956 blk_rq_sectors(req), good_bytes));
959 * Next deal with any sectors which we were able to correctly
960 * handle. Failed, zero length commands always need to drop down
961 * to retry code. Fast path should return in this block.
963 if (likely(blk_rq_bytes(req) > 0 || blk_stat == BLK_STS_OK)) {
964 if (likely(!scsi_end_request(req, blk_stat, good_bytes)))
965 return; /* no bytes remaining */
968 /* Kill remainder if no retries. */
969 if (unlikely(blk_stat && scsi_noretry_cmd(cmd))) {
970 if (scsi_end_request(req, blk_stat, blk_rq_bytes(req)))
972 "Bytes remaining after failed, no-retry command");
977 * If there had been no error, but we have leftover bytes in the
978 * requeues just queue the command up again.
980 if (likely(result == 0))
981 scsi_io_completion_reprep(cmd, q);
983 scsi_io_completion_action(cmd, result);
986 static blk_status_t scsi_init_sgtable(struct request *req,
987 struct scsi_data_buffer *sdb)
992 * If sg table allocation fails, requeue request later.
994 if (unlikely(sg_alloc_table_chained(&sdb->table,
995 blk_rq_nr_phys_segments(req), sdb->table.sgl)))
996 return BLK_STS_RESOURCE;
999 * Next, walk the list, and fill in the addresses and sizes of
1002 count = blk_rq_map_sg(req->q, req, sdb->table.sgl);
1003 BUG_ON(count > sdb->table.nents);
1004 sdb->table.nents = count;
1005 sdb->length = blk_rq_payload_bytes(req);
1010 * Function: scsi_init_io()
1012 * Purpose: SCSI I/O initialize function.
1014 * Arguments: cmd - Command descriptor we wish to initialize
1016 * Returns: BLK_STS_OK on success
1017 * BLK_STS_RESOURCE if the failure is retryable
1018 * BLK_STS_IOERR if the failure is fatal
1020 blk_status_t scsi_init_io(struct scsi_cmnd *cmd)
1022 struct request *rq = cmd->request;
1025 if (WARN_ON_ONCE(!blk_rq_nr_phys_segments(rq)))
1026 return BLK_STS_IOERR;
1028 ret = scsi_init_sgtable(rq, &cmd->sdb);
1032 if (blk_integrity_rq(rq)) {
1033 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1036 if (WARN_ON_ONCE(!prot_sdb)) {
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.
1042 ret = BLK_STS_IOERR;
1043 goto out_free_sgtables;
1046 ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
1048 if (sg_alloc_table_chained(&prot_sdb->table, ivecs,
1049 prot_sdb->table.sgl)) {
1050 ret = BLK_STS_RESOURCE;
1051 goto out_free_sgtables;
1054 count = blk_rq_map_integrity_sg(rq->q, rq->bio,
1055 prot_sdb->table.sgl);
1056 BUG_ON(count > ivecs);
1057 BUG_ON(count > queue_max_integrity_segments(rq->q));
1059 cmd->prot_sdb = prot_sdb;
1060 cmd->prot_sdb->table.nents = count;
1065 scsi_mq_free_sgtables(cmd);
1068 EXPORT_SYMBOL(scsi_init_io);
1071 * scsi_initialize_rq - initialize struct scsi_cmnd partially
1072 * @rq: Request associated with the SCSI command to be initialized.
1074 * This function initializes the members of struct scsi_cmnd that must be
1075 * initialized before request processing starts and that won't be
1076 * reinitialized if a SCSI command is requeued.
1078 * Called from inside blk_get_request() for pass-through requests and from
1079 * inside scsi_init_command() for filesystem requests.
1081 static void scsi_initialize_rq(struct request *rq)
1083 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1085 scsi_req_init(&cmd->req);
1086 init_rcu_head(&cmd->rcu);
1087 cmd->jiffies_at_alloc = jiffies;
1091 /* Add a command to the list used by the aacraid and dpt_i2o drivers */
1092 void scsi_add_cmd_to_list(struct scsi_cmnd *cmd)
1094 struct scsi_device *sdev = cmd->device;
1095 struct Scsi_Host *shost = sdev->host;
1096 unsigned long flags;
1098 if (shost->use_cmd_list) {
1099 spin_lock_irqsave(&sdev->list_lock, flags);
1100 list_add_tail(&cmd->list, &sdev->cmd_list);
1101 spin_unlock_irqrestore(&sdev->list_lock, flags);
1105 /* Remove a command from the list used by the aacraid and dpt_i2o drivers */
1106 void scsi_del_cmd_from_list(struct scsi_cmnd *cmd)
1108 struct scsi_device *sdev = cmd->device;
1109 struct Scsi_Host *shost = sdev->host;
1110 unsigned long flags;
1112 if (shost->use_cmd_list) {
1113 spin_lock_irqsave(&sdev->list_lock, flags);
1114 BUG_ON(list_empty(&cmd->list));
1115 list_del_init(&cmd->list);
1116 spin_unlock_irqrestore(&sdev->list_lock, flags);
1120 /* Called after a request has been started. */
1121 void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd)
1123 void *buf = cmd->sense_buffer;
1124 void *prot = cmd->prot_sdb;
1125 struct request *rq = blk_mq_rq_from_pdu(cmd);
1126 unsigned int flags = cmd->flags & SCMD_PRESERVED_FLAGS;
1127 unsigned long jiffies_at_alloc;
1130 if (!blk_rq_is_scsi(rq) && !(flags & SCMD_INITIALIZED)) {
1131 flags |= SCMD_INITIALIZED;
1132 scsi_initialize_rq(rq);
1135 jiffies_at_alloc = cmd->jiffies_at_alloc;
1136 retries = cmd->retries;
1137 /* zero out the cmd, except for the embedded scsi_request */
1138 memset((char *)cmd + sizeof(cmd->req), 0,
1139 sizeof(*cmd) - sizeof(cmd->req) + dev->host->hostt->cmd_size);
1142 cmd->sense_buffer = buf;
1143 cmd->prot_sdb = prot;
1145 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
1146 cmd->jiffies_at_alloc = jiffies_at_alloc;
1147 cmd->retries = retries;
1149 scsi_add_cmd_to_list(cmd);
1152 static blk_status_t scsi_setup_scsi_cmnd(struct scsi_device *sdev,
1153 struct request *req)
1155 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1158 * Passthrough requests may transfer data, in which case they must
1159 * a bio attached to them. Or they might contain a SCSI command
1160 * that does not transfer data, in which case they may optionally
1161 * submit a request without an attached bio.
1164 blk_status_t ret = scsi_init_io(cmd);
1165 if (unlikely(ret != BLK_STS_OK))
1168 BUG_ON(blk_rq_bytes(req));
1170 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1173 cmd->cmd_len = scsi_req(req)->cmd_len;
1174 cmd->cmnd = scsi_req(req)->cmd;
1175 cmd->transfersize = blk_rq_bytes(req);
1176 cmd->allowed = scsi_req(req)->retries;
1181 * Setup a normal block command. These are simple request from filesystems
1182 * that still need to be translated to SCSI CDBs from the ULD.
1184 static blk_status_t scsi_setup_fs_cmnd(struct scsi_device *sdev,
1185 struct request *req)
1187 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1189 if (unlikely(sdev->handler && sdev->handler->prep_fn)) {
1190 blk_status_t ret = sdev->handler->prep_fn(sdev, req);
1191 if (ret != BLK_STS_OK)
1195 cmd->cmnd = scsi_req(req)->cmd = scsi_req(req)->__cmd;
1196 memset(cmd->cmnd, 0, BLK_MAX_CDB);
1197 return scsi_cmd_to_driver(cmd)->init_command(cmd);
1200 static blk_status_t scsi_setup_cmnd(struct scsi_device *sdev,
1201 struct request *req)
1203 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1205 if (!blk_rq_bytes(req))
1206 cmd->sc_data_direction = DMA_NONE;
1207 else if (rq_data_dir(req) == WRITE)
1208 cmd->sc_data_direction = DMA_TO_DEVICE;
1210 cmd->sc_data_direction = DMA_FROM_DEVICE;
1212 if (blk_rq_is_scsi(req))
1213 return scsi_setup_scsi_cmnd(sdev, req);
1215 return scsi_setup_fs_cmnd(sdev, req);
1219 scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
1221 switch (sdev->sdev_state) {
1223 case SDEV_TRANSPORT_OFFLINE:
1225 * If the device is offline we refuse to process any
1226 * commands. The device must be brought online
1227 * before trying any recovery commands.
1229 sdev_printk(KERN_ERR, sdev,
1230 "rejecting I/O to offline device\n");
1231 return BLK_STS_IOERR;
1234 * If the device is fully deleted, we refuse to
1235 * process any commands as well.
1237 sdev_printk(KERN_ERR, sdev,
1238 "rejecting I/O to dead device\n");
1239 return BLK_STS_IOERR;
1241 case SDEV_CREATED_BLOCK:
1242 return BLK_STS_RESOURCE;
1245 * If the devices is blocked we defer normal commands.
1247 if (req && !(req->rq_flags & RQF_PREEMPT))
1248 return BLK_STS_RESOURCE;
1252 * For any other not fully online state we only allow
1253 * special commands. In particular any user initiated
1254 * command is not allowed.
1256 if (req && !(req->rq_flags & RQF_PREEMPT))
1257 return BLK_STS_IOERR;
1263 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1266 * Called with the queue_lock held.
1268 static inline int scsi_dev_queue_ready(struct request_queue *q,
1269 struct scsi_device *sdev)
1273 busy = atomic_inc_return(&sdev->device_busy) - 1;
1274 if (atomic_read(&sdev->device_blocked)) {
1279 * unblock after device_blocked iterates to zero
1281 if (atomic_dec_return(&sdev->device_blocked) > 0)
1283 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev,
1284 "unblocking device at zero depth\n"));
1287 if (busy >= sdev->queue_depth)
1292 atomic_dec(&sdev->device_busy);
1297 * scsi_target_queue_ready: checks if there we can send commands to target
1298 * @sdev: scsi device on starget to check.
1300 static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1301 struct scsi_device *sdev)
1303 struct scsi_target *starget = scsi_target(sdev);
1306 if (starget->single_lun) {
1307 spin_lock_irq(shost->host_lock);
1308 if (starget->starget_sdev_user &&
1309 starget->starget_sdev_user != sdev) {
1310 spin_unlock_irq(shost->host_lock);
1313 starget->starget_sdev_user = sdev;
1314 spin_unlock_irq(shost->host_lock);
1317 if (starget->can_queue <= 0)
1320 busy = atomic_inc_return(&starget->target_busy) - 1;
1321 if (atomic_read(&starget->target_blocked) > 0) {
1326 * unblock after target_blocked iterates to zero
1328 if (atomic_dec_return(&starget->target_blocked) > 0)
1331 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1332 "unblocking target at zero depth\n"));
1335 if (busy >= starget->can_queue)
1341 spin_lock_irq(shost->host_lock);
1342 list_move_tail(&sdev->starved_entry, &shost->starved_list);
1343 spin_unlock_irq(shost->host_lock);
1345 if (starget->can_queue > 0)
1346 atomic_dec(&starget->target_busy);
1351 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1352 * return 0. We must end up running the queue again whenever 0 is
1353 * returned, else IO can hang.
1355 static inline int scsi_host_queue_ready(struct request_queue *q,
1356 struct Scsi_Host *shost,
1357 struct scsi_device *sdev)
1361 if (scsi_host_in_recovery(shost))
1364 busy = atomic_inc_return(&shost->host_busy) - 1;
1365 if (atomic_read(&shost->host_blocked) > 0) {
1370 * unblock after host_blocked iterates to zero
1372 if (atomic_dec_return(&shost->host_blocked) > 0)
1376 shost_printk(KERN_INFO, shost,
1377 "unblocking host at zero depth\n"));
1380 if (shost->can_queue > 0 && busy >= shost->can_queue)
1382 if (shost->host_self_blocked)
1385 /* We're OK to process the command, so we can't be starved */
1386 if (!list_empty(&sdev->starved_entry)) {
1387 spin_lock_irq(shost->host_lock);
1388 if (!list_empty(&sdev->starved_entry))
1389 list_del_init(&sdev->starved_entry);
1390 spin_unlock_irq(shost->host_lock);
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);
1401 scsi_dec_host_busy(shost);
1406 * Busy state exporting function for request stacking drivers.
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.
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.
1417 static bool scsi_mq_lld_busy(struct request_queue *q)
1419 struct scsi_device *sdev = q->queuedata;
1420 struct Scsi_Host *shost;
1422 if (blk_queue_dying(q))
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
1433 if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
1439 static void scsi_softirq_done(struct request *rq)
1441 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1442 unsigned long wait_for = (cmd->allowed + 1) * rq->timeout;
1445 INIT_LIST_HEAD(&cmd->eh_entry);
1447 atomic_inc(&cmd->device->iodone_cnt);
1449 atomic_inc(&cmd->device->ioerr_cnt);
1451 disposition = scsi_decide_disposition(cmd);
1452 if (disposition != SUCCESS &&
1453 time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
1454 sdev_printk(KERN_ERR, cmd->device,
1455 "timing out command, waited %lus\n",
1457 disposition = SUCCESS;
1460 scsi_log_completion(cmd, disposition);
1462 switch (disposition) {
1464 scsi_finish_command(cmd);
1467 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
1469 case ADD_TO_MLQUEUE:
1470 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1473 scsi_eh_scmd_add(cmd);
1479 * scsi_dispatch_command - Dispatch a command to the low-level driver.
1480 * @cmd: command block we are dispatching.
1482 * Return: nonzero return request was rejected and device's queue needs to be
1485 static int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
1487 struct Scsi_Host *host = cmd->device->host;
1490 atomic_inc(&cmd->device->iorequest_cnt);
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;
1501 /* Check to see if the scsi lld made this device blocked. */
1502 if (unlikely(scsi_device_blocked(cmd->device))) {
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
1510 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1511 "queuecommand : device blocked\n"));
1512 return SCSI_MLQUEUE_DEVICE_BUSY;
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);
1523 * Before we queue this command, check if the command
1524 * length exceeds what the host adapter can handle.
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);
1535 if (unlikely(host->shost_state == SHOST_DEL)) {
1536 cmd->result = (DID_NO_CONNECT << 16);
1541 trace_scsi_dispatch_cmd_start(cmd);
1542 rtn = host->hostt->queuecommand(host, cmd);
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;
1549 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1550 "queuecommand : request rejected\n"));
1555 cmd->scsi_done(cmd);
1559 /* Size in bytes of the sg-list stored in the scsi-mq command-private data. */
1560 static unsigned int scsi_mq_sgl_size(struct Scsi_Host *shost)
1562 return min_t(unsigned int, shost->sg_tablesize, SG_CHUNK_SIZE) *
1563 sizeof(struct scatterlist);
1566 static blk_status_t scsi_mq_prep_fn(struct request *req)
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;
1573 scsi_init_command(sdev, cmd);
1576 cmd->tag = req->tag;
1577 cmd->prot_op = SCSI_PROT_NORMAL;
1579 sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
1580 cmd->sdb.table.sgl = sg;
1582 if (scsi_host_get_prot(shost)) {
1583 memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer));
1585 cmd->prot_sdb->table.sgl =
1586 (struct scatterlist *)(cmd->prot_sdb + 1);
1589 blk_mq_start_request(req);
1591 return scsi_setup_cmnd(sdev, req);
1594 static void scsi_mq_done(struct scsi_cmnd *cmd)
1596 if (unlikely(test_and_set_bit(SCMD_STATE_COMPLETE, &cmd->state)))
1598 trace_scsi_dispatch_cmd_done(cmd);
1601 * If the block layer didn't complete the request due to a timeout
1602 * injection, scsi must clear its internal completed state so that the
1603 * timeout handler will see it needs to escalate its own error
1606 if (unlikely(!blk_mq_complete_request(cmd->request)))
1607 clear_bit(SCMD_STATE_COMPLETE, &cmd->state);
1610 static void scsi_mq_put_budget(struct blk_mq_hw_ctx *hctx)
1612 struct request_queue *q = hctx->queue;
1613 struct scsi_device *sdev = q->queuedata;
1615 atomic_dec(&sdev->device_busy);
1616 put_device(&sdev->sdev_gendev);
1619 static bool scsi_mq_get_budget(struct blk_mq_hw_ctx *hctx)
1621 struct request_queue *q = hctx->queue;
1622 struct scsi_device *sdev = q->queuedata;
1624 if (!get_device(&sdev->sdev_gendev))
1626 if (!scsi_dev_queue_ready(q, sdev))
1627 goto out_put_device;
1632 put_device(&sdev->sdev_gendev);
1634 if (atomic_read(&sdev->device_busy) == 0 && !scsi_device_blocked(sdev))
1635 blk_mq_delay_run_hw_queue(hctx, SCSI_QUEUE_DELAY);
1639 static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
1640 const struct blk_mq_queue_data *bd)
1642 struct request *req = bd->rq;
1643 struct request_queue *q = req->q;
1644 struct scsi_device *sdev = q->queuedata;
1645 struct Scsi_Host *shost = sdev->host;
1646 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1651 * If the device is not in running state we will reject some or all
1654 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
1655 ret = scsi_prep_state_check(sdev, req);
1656 if (ret != BLK_STS_OK)
1657 goto out_put_budget;
1660 ret = BLK_STS_RESOURCE;
1661 if (!scsi_target_queue_ready(shost, sdev))
1662 goto out_put_budget;
1663 if (!scsi_host_queue_ready(q, shost, sdev))
1664 goto out_dec_target_busy;
1666 if (!(req->rq_flags & RQF_DONTPREP)) {
1667 ret = scsi_mq_prep_fn(req);
1668 if (ret != BLK_STS_OK)
1669 goto out_dec_host_busy;
1670 req->rq_flags |= RQF_DONTPREP;
1672 clear_bit(SCMD_STATE_COMPLETE, &cmd->state);
1673 blk_mq_start_request(req);
1676 if (sdev->simple_tags)
1677 cmd->flags |= SCMD_TAGGED;
1679 cmd->flags &= ~SCMD_TAGGED;
1681 scsi_init_cmd_errh(cmd);
1682 cmd->scsi_done = scsi_mq_done;
1684 reason = scsi_dispatch_cmd(cmd);
1686 scsi_set_blocked(cmd, reason);
1687 ret = BLK_STS_RESOURCE;
1688 goto out_dec_host_busy;
1694 scsi_dec_host_busy(shost);
1695 out_dec_target_busy:
1696 if (scsi_target(sdev)->can_queue > 0)
1697 atomic_dec(&scsi_target(sdev)->target_busy);
1699 scsi_mq_put_budget(hctx);
1703 case BLK_STS_RESOURCE:
1704 if (atomic_read(&sdev->device_busy) ||
1705 scsi_device_blocked(sdev))
1706 ret = BLK_STS_DEV_RESOURCE;
1709 if (unlikely(!scsi_device_online(sdev)))
1710 scsi_req(req)->result = DID_NO_CONNECT << 16;
1712 scsi_req(req)->result = DID_ERROR << 16;
1714 * Make sure to release all allocated resources when
1715 * we hit an error, as we will never see this command
1718 if (req->rq_flags & RQF_DONTPREP)
1719 scsi_mq_uninit_cmd(cmd);
1725 static enum blk_eh_timer_return scsi_timeout(struct request *req,
1729 return BLK_EH_RESET_TIMER;
1730 return scsi_times_out(req);
1733 static int scsi_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
1734 unsigned int hctx_idx, unsigned int numa_node)
1736 struct Scsi_Host *shost = set->driver_data;
1737 const bool unchecked_isa_dma = shost->unchecked_isa_dma;
1738 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1739 struct scatterlist *sg;
1741 if (unchecked_isa_dma)
1742 cmd->flags |= SCMD_UNCHECKED_ISA_DMA;
1743 cmd->sense_buffer = scsi_alloc_sense_buffer(unchecked_isa_dma,
1744 GFP_KERNEL, numa_node);
1745 if (!cmd->sense_buffer)
1747 cmd->req.sense = cmd->sense_buffer;
1749 if (scsi_host_get_prot(shost)) {
1750 sg = (void *)cmd + sizeof(struct scsi_cmnd) +
1751 shost->hostt->cmd_size;
1752 cmd->prot_sdb = (void *)sg + scsi_mq_sgl_size(shost);
1758 static void scsi_mq_exit_request(struct blk_mq_tag_set *set, struct request *rq,
1759 unsigned int hctx_idx)
1761 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1763 scsi_free_sense_buffer(cmd->flags & SCMD_UNCHECKED_ISA_DMA,
1767 static int scsi_map_queues(struct blk_mq_tag_set *set)
1769 struct Scsi_Host *shost = container_of(set, struct Scsi_Host, tag_set);
1771 if (shost->hostt->map_queues)
1772 return shost->hostt->map_queues(shost);
1773 return blk_mq_map_queues(&set->map[0]);
1776 void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
1778 struct device *dev = shost->dma_dev;
1781 * this limit is imposed by hardware restrictions
1783 blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
1786 if (scsi_host_prot_dma(shost)) {
1787 shost->sg_prot_tablesize =
1788 min_not_zero(shost->sg_prot_tablesize,
1789 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
1790 BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
1791 blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
1794 blk_queue_max_hw_sectors(q, shost->max_sectors);
1795 if (shost->unchecked_isa_dma)
1796 blk_queue_bounce_limit(q, BLK_BOUNCE_ISA);
1797 blk_queue_segment_boundary(q, shost->dma_boundary);
1798 dma_set_seg_boundary(dev, shost->dma_boundary);
1800 blk_queue_max_segment_size(q, shost->max_segment_size);
1801 dma_set_max_seg_size(dev, shost->max_segment_size);
1804 * Set a reasonable default alignment: The larger of 32-byte (dword),
1805 * which is a common minimum for HBAs, and the minimum DMA alignment,
1806 * which is set by the platform.
1808 * Devices that require a bigger alignment can increase it later.
1810 blk_queue_dma_alignment(q, max(4, dma_get_cache_alignment()) - 1);
1812 EXPORT_SYMBOL_GPL(__scsi_init_queue);
1814 static const struct blk_mq_ops scsi_mq_ops = {
1815 .get_budget = scsi_mq_get_budget,
1816 .put_budget = scsi_mq_put_budget,
1817 .queue_rq = scsi_queue_rq,
1818 .complete = scsi_softirq_done,
1819 .timeout = scsi_timeout,
1820 #ifdef CONFIG_BLK_DEBUG_FS
1821 .show_rq = scsi_show_rq,
1823 .init_request = scsi_mq_init_request,
1824 .exit_request = scsi_mq_exit_request,
1825 .initialize_rq_fn = scsi_initialize_rq,
1826 .busy = scsi_mq_lld_busy,
1827 .map_queues = scsi_map_queues,
1830 struct request_queue *scsi_mq_alloc_queue(struct scsi_device *sdev)
1832 sdev->request_queue = blk_mq_init_queue(&sdev->host->tag_set);
1833 if (IS_ERR(sdev->request_queue))
1836 sdev->request_queue->queuedata = sdev;
1837 __scsi_init_queue(sdev->host, sdev->request_queue);
1838 blk_queue_flag_set(QUEUE_FLAG_SCSI_PASSTHROUGH, sdev->request_queue);
1839 return sdev->request_queue;
1842 int scsi_mq_setup_tags(struct Scsi_Host *shost)
1844 unsigned int cmd_size, sgl_size;
1846 sgl_size = scsi_mq_sgl_size(shost);
1847 cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size;
1848 if (scsi_host_get_prot(shost))
1849 cmd_size += sizeof(struct scsi_data_buffer) + sgl_size;
1851 memset(&shost->tag_set, 0, sizeof(shost->tag_set));
1852 shost->tag_set.ops = &scsi_mq_ops;
1853 shost->tag_set.nr_hw_queues = shost->nr_hw_queues ? : 1;
1854 shost->tag_set.queue_depth = shost->can_queue;
1855 shost->tag_set.cmd_size = cmd_size;
1856 shost->tag_set.numa_node = NUMA_NO_NODE;
1857 shost->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
1858 shost->tag_set.flags |=
1859 BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
1860 shost->tag_set.driver_data = shost;
1862 return blk_mq_alloc_tag_set(&shost->tag_set);
1865 void scsi_mq_destroy_tags(struct Scsi_Host *shost)
1867 blk_mq_free_tag_set(&shost->tag_set);
1871 * scsi_device_from_queue - return sdev associated with a request_queue
1872 * @q: The request queue to return the sdev from
1874 * Return the sdev associated with a request queue or NULL if the
1875 * request_queue does not reference a SCSI device.
1877 struct scsi_device *scsi_device_from_queue(struct request_queue *q)
1879 struct scsi_device *sdev = NULL;
1881 if (q->mq_ops == &scsi_mq_ops)
1882 sdev = q->queuedata;
1883 if (!sdev || !get_device(&sdev->sdev_gendev))
1888 EXPORT_SYMBOL_GPL(scsi_device_from_queue);
1891 * Function: scsi_block_requests()
1893 * Purpose: Utility function used by low-level drivers to prevent further
1894 * commands from being queued to the device.
1896 * Arguments: shost - Host in question
1900 * Lock status: No locks are assumed held.
1902 * Notes: There is no timer nor any other means by which the requests
1903 * get unblocked other than the low-level driver calling
1904 * scsi_unblock_requests().
1906 void scsi_block_requests(struct Scsi_Host *shost)
1908 shost->host_self_blocked = 1;
1910 EXPORT_SYMBOL(scsi_block_requests);
1913 * Function: scsi_unblock_requests()
1915 * Purpose: Utility function used by low-level drivers to allow further
1916 * commands from being queued to the device.
1918 * Arguments: shost - Host in question
1922 * Lock status: No locks are assumed held.
1924 * Notes: There is no timer nor any other means by which the requests
1925 * get unblocked other than the low-level driver calling
1926 * scsi_unblock_requests().
1928 * This is done as an API function so that changes to the
1929 * internals of the scsi mid-layer won't require wholesale
1930 * changes to drivers that use this feature.
1932 void scsi_unblock_requests(struct Scsi_Host *shost)
1934 shost->host_self_blocked = 0;
1935 scsi_run_host_queues(shost);
1937 EXPORT_SYMBOL(scsi_unblock_requests);
1939 int __init scsi_init_queue(void)
1941 scsi_sdb_cache = kmem_cache_create("scsi_data_buffer",
1942 sizeof(struct scsi_data_buffer),
1944 if (!scsi_sdb_cache) {
1945 printk(KERN_ERR "SCSI: can't init scsi sdb cache\n");
1952 void scsi_exit_queue(void)
1954 kmem_cache_destroy(scsi_sense_cache);
1955 kmem_cache_destroy(scsi_sense_isadma_cache);
1956 kmem_cache_destroy(scsi_sdb_cache);
1960 * scsi_mode_select - issue a mode select
1961 * @sdev: SCSI device to be queried
1962 * @pf: Page format bit (1 == standard, 0 == vendor specific)
1963 * @sp: Save page bit (0 == don't save, 1 == save)
1964 * @modepage: mode page being requested
1965 * @buffer: request buffer (may not be smaller than eight bytes)
1966 * @len: length of request buffer.
1967 * @timeout: command timeout
1968 * @retries: number of retries before failing
1969 * @data: returns a structure abstracting the mode header data
1970 * @sshdr: place to put sense data (or NULL if no sense to be collected).
1971 * must be SCSI_SENSE_BUFFERSIZE big.
1973 * Returns zero if successful; negative error number or scsi
1978 scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
1979 unsigned char *buffer, int len, int timeout, int retries,
1980 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
1982 unsigned char cmd[10];
1983 unsigned char *real_buffer;
1986 memset(cmd, 0, sizeof(cmd));
1987 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
1989 if (sdev->use_10_for_ms) {
1992 real_buffer = kmalloc(8 + len, GFP_KERNEL);
1995 memcpy(real_buffer + 8, buffer, len);
1999 real_buffer[2] = data->medium_type;
2000 real_buffer[3] = data->device_specific;
2001 real_buffer[4] = data->longlba ? 0x01 : 0;
2003 real_buffer[6] = data->block_descriptor_length >> 8;
2004 real_buffer[7] = data->block_descriptor_length;
2006 cmd[0] = MODE_SELECT_10;
2010 if (len > 255 || data->block_descriptor_length > 255 ||
2014 real_buffer = kmalloc(4 + len, GFP_KERNEL);
2017 memcpy(real_buffer + 4, buffer, len);
2020 real_buffer[1] = data->medium_type;
2021 real_buffer[2] = data->device_specific;
2022 real_buffer[3] = data->block_descriptor_length;
2025 cmd[0] = MODE_SELECT;
2029 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
2030 sshdr, timeout, retries, NULL);
2034 EXPORT_SYMBOL_GPL(scsi_mode_select);
2037 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
2038 * @sdev: SCSI device to be queried
2039 * @dbd: set if mode sense will allow block descriptors to be returned
2040 * @modepage: mode page being requested
2041 * @buffer: request buffer (may not be smaller than eight bytes)
2042 * @len: length of request buffer.
2043 * @timeout: command timeout
2044 * @retries: number of retries before failing
2045 * @data: returns a structure abstracting the mode header data
2046 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2047 * must be SCSI_SENSE_BUFFERSIZE big.
2049 * Returns zero if unsuccessful, or the header offset (either 4
2050 * or 8 depending on whether a six or ten byte command was
2051 * issued) if successful.
2054 scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
2055 unsigned char *buffer, int len, int timeout, int retries,
2056 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2058 unsigned char cmd[12];
2061 int result, retry_count = retries;
2062 struct scsi_sense_hdr my_sshdr;
2064 memset(data, 0, sizeof(*data));
2065 memset(&cmd[0], 0, 12);
2066 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
2069 /* caller might not be interested in sense, but we need it */
2074 use_10_for_ms = sdev->use_10_for_ms;
2076 if (use_10_for_ms) {
2080 cmd[0] = MODE_SENSE_10;
2087 cmd[0] = MODE_SENSE;
2092 memset(buffer, 0, len);
2094 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
2095 sshdr, timeout, retries, NULL);
2097 /* This code looks awful: what it's doing is making sure an
2098 * ILLEGAL REQUEST sense return identifies the actual command
2099 * byte as the problem. MODE_SENSE commands can return
2100 * ILLEGAL REQUEST if the code page isn't supported */
2102 if (use_10_for_ms && !scsi_status_is_good(result) &&
2103 driver_byte(result) == DRIVER_SENSE) {
2104 if (scsi_sense_valid(sshdr)) {
2105 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
2106 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
2108 * Invalid command operation code
2110 sdev->use_10_for_ms = 0;
2116 if(scsi_status_is_good(result)) {
2117 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
2118 (modepage == 6 || modepage == 8))) {
2119 /* Initio breakage? */
2122 data->medium_type = 0;
2123 data->device_specific = 0;
2125 data->block_descriptor_length = 0;
2126 } else if(use_10_for_ms) {
2127 data->length = buffer[0]*256 + buffer[1] + 2;
2128 data->medium_type = buffer[2];
2129 data->device_specific = buffer[3];
2130 data->longlba = buffer[4] & 0x01;
2131 data->block_descriptor_length = buffer[6]*256
2134 data->length = buffer[0] + 1;
2135 data->medium_type = buffer[1];
2136 data->device_specific = buffer[2];
2137 data->block_descriptor_length = buffer[3];
2139 data->header_length = header_length;
2140 } else if ((status_byte(result) == CHECK_CONDITION) &&
2141 scsi_sense_valid(sshdr) &&
2142 sshdr->sense_key == UNIT_ATTENTION && retry_count) {
2149 EXPORT_SYMBOL(scsi_mode_sense);
2152 * scsi_test_unit_ready - test if unit is ready
2153 * @sdev: scsi device to change the state of.
2154 * @timeout: command timeout
2155 * @retries: number of retries before failing
2156 * @sshdr: outpout pointer for decoded sense information.
2158 * Returns zero if unsuccessful or an error if TUR failed. For
2159 * removable media, UNIT_ATTENTION sets ->changed flag.
2162 scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2163 struct scsi_sense_hdr *sshdr)
2166 TEST_UNIT_READY, 0, 0, 0, 0, 0,
2170 /* try to eat the UNIT_ATTENTION if there are enough retries */
2172 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
2174 if (sdev->removable && scsi_sense_valid(sshdr) &&
2175 sshdr->sense_key == UNIT_ATTENTION)
2177 } while (scsi_sense_valid(sshdr) &&
2178 sshdr->sense_key == UNIT_ATTENTION && --retries);
2182 EXPORT_SYMBOL(scsi_test_unit_ready);
2185 * scsi_device_set_state - Take the given device through the device state model.
2186 * @sdev: scsi device to change the state of.
2187 * @state: state to change to.
2189 * Returns zero if successful or an error if the requested
2190 * transition is illegal.
2193 scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2195 enum scsi_device_state oldstate = sdev->sdev_state;
2197 if (state == oldstate)
2203 case SDEV_CREATED_BLOCK:
2214 case SDEV_TRANSPORT_OFFLINE:
2227 case SDEV_TRANSPORT_OFFLINE:
2235 case SDEV_TRANSPORT_OFFLINE:
2250 case SDEV_CREATED_BLOCK:
2258 case SDEV_CREATED_BLOCK:
2273 case SDEV_TRANSPORT_OFFLINE:
2285 case SDEV_TRANSPORT_OFFLINE:
2288 case SDEV_CREATED_BLOCK:
2296 sdev->sdev_state = state;
2300 SCSI_LOG_ERROR_RECOVERY(1,
2301 sdev_printk(KERN_ERR, sdev,
2302 "Illegal state transition %s->%s",
2303 scsi_device_state_name(oldstate),
2304 scsi_device_state_name(state))
2308 EXPORT_SYMBOL(scsi_device_set_state);
2311 * sdev_evt_emit - emit a single SCSI device uevent
2312 * @sdev: associated SCSI device
2313 * @evt: event to emit
2315 * Send a single uevent (scsi_event) to the associated scsi_device.
2317 static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2322 switch (evt->evt_type) {
2323 case SDEV_EVT_MEDIA_CHANGE:
2324 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2326 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2327 scsi_rescan_device(&sdev->sdev_gendev);
2328 envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2330 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2331 envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2333 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2334 envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2336 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2337 envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2339 case SDEV_EVT_LUN_CHANGE_REPORTED:
2340 envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2342 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2343 envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
2345 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2346 envp[idx++] = "SDEV_UA=POWER_ON_RESET_OCCURRED";
2355 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2359 * sdev_evt_thread - send a uevent for each scsi event
2360 * @work: work struct for scsi_device
2362 * Dispatch queued events to their associated scsi_device kobjects
2365 void scsi_evt_thread(struct work_struct *work)
2367 struct scsi_device *sdev;
2368 enum scsi_device_event evt_type;
2369 LIST_HEAD(event_list);
2371 sdev = container_of(work, struct scsi_device, event_work);
2373 for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
2374 if (test_and_clear_bit(evt_type, sdev->pending_events))
2375 sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
2378 struct scsi_event *evt;
2379 struct list_head *this, *tmp;
2380 unsigned long flags;
2382 spin_lock_irqsave(&sdev->list_lock, flags);
2383 list_splice_init(&sdev->event_list, &event_list);
2384 spin_unlock_irqrestore(&sdev->list_lock, flags);
2386 if (list_empty(&event_list))
2389 list_for_each_safe(this, tmp, &event_list) {
2390 evt = list_entry(this, struct scsi_event, node);
2391 list_del(&evt->node);
2392 scsi_evt_emit(sdev, evt);
2399 * sdev_evt_send - send asserted event to uevent thread
2400 * @sdev: scsi_device event occurred on
2401 * @evt: event to send
2403 * Assert scsi device event asynchronously.
2405 void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2407 unsigned long flags;
2410 /* FIXME: currently this check eliminates all media change events
2411 * for polled devices. Need to update to discriminate between AN
2412 * and polled events */
2413 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2419 spin_lock_irqsave(&sdev->list_lock, flags);
2420 list_add_tail(&evt->node, &sdev->event_list);
2421 schedule_work(&sdev->event_work);
2422 spin_unlock_irqrestore(&sdev->list_lock, flags);
2424 EXPORT_SYMBOL_GPL(sdev_evt_send);
2427 * sdev_evt_alloc - allocate a new scsi event
2428 * @evt_type: type of event to allocate
2429 * @gfpflags: GFP flags for allocation
2431 * Allocates and returns a new scsi_event.
2433 struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2436 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2440 evt->evt_type = evt_type;
2441 INIT_LIST_HEAD(&evt->node);
2443 /* evt_type-specific initialization, if any */
2445 case SDEV_EVT_MEDIA_CHANGE:
2446 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2447 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2448 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2449 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2450 case SDEV_EVT_LUN_CHANGE_REPORTED:
2451 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2452 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2460 EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2463 * sdev_evt_send_simple - send asserted event to uevent thread
2464 * @sdev: scsi_device event occurred on
2465 * @evt_type: type of event to send
2466 * @gfpflags: GFP flags for allocation
2468 * Assert scsi device event asynchronously, given an event type.
2470 void sdev_evt_send_simple(struct scsi_device *sdev,
2471 enum scsi_device_event evt_type, gfp_t gfpflags)
2473 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2475 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2480 sdev_evt_send(sdev, evt);
2482 EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2485 * scsi_device_quiesce - Block user issued commands.
2486 * @sdev: scsi device to quiesce.
2488 * This works by trying to transition to the SDEV_QUIESCE state
2489 * (which must be a legal transition). When the device is in this
2490 * state, only special requests will be accepted, all others will
2491 * be deferred. Since special requests may also be requeued requests,
2492 * a successful return doesn't guarantee the device will be
2493 * totally quiescent.
2495 * Must be called with user context, may sleep.
2497 * Returns zero if unsuccessful or an error if not.
2500 scsi_device_quiesce(struct scsi_device *sdev)
2502 struct request_queue *q = sdev->request_queue;
2506 * It is allowed to call scsi_device_quiesce() multiple times from
2507 * the same context but concurrent scsi_device_quiesce() calls are
2510 WARN_ON_ONCE(sdev->quiesced_by && sdev->quiesced_by != current);
2512 if (sdev->quiesced_by == current)
2517 blk_mq_freeze_queue(q);
2519 * Ensure that the effect of blk_set_pm_only() will be visible
2520 * for percpu_ref_tryget() callers that occur after the queue
2521 * unfreeze even if the queue was already frozen before this function
2522 * was called. See also https://lwn.net/Articles/573497/.
2525 blk_mq_unfreeze_queue(q);
2527 mutex_lock(&sdev->state_mutex);
2528 err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2530 sdev->quiesced_by = current;
2532 blk_clear_pm_only(q);
2533 mutex_unlock(&sdev->state_mutex);
2537 EXPORT_SYMBOL(scsi_device_quiesce);
2540 * scsi_device_resume - Restart user issued commands to a quiesced device.
2541 * @sdev: scsi device to resume.
2543 * Moves the device from quiesced back to running and restarts the
2546 * Must be called with user context, may sleep.
2548 void scsi_device_resume(struct scsi_device *sdev)
2550 /* check if the device state was mutated prior to resume, and if
2551 * so assume the state is being managed elsewhere (for example
2552 * device deleted during suspend)
2554 mutex_lock(&sdev->state_mutex);
2555 if (sdev->quiesced_by) {
2556 sdev->quiesced_by = NULL;
2557 blk_clear_pm_only(sdev->request_queue);
2559 if (sdev->sdev_state == SDEV_QUIESCE)
2560 scsi_device_set_state(sdev, SDEV_RUNNING);
2561 mutex_unlock(&sdev->state_mutex);
2563 EXPORT_SYMBOL(scsi_device_resume);
2566 device_quiesce_fn(struct scsi_device *sdev, void *data)
2568 scsi_device_quiesce(sdev);
2572 scsi_target_quiesce(struct scsi_target *starget)
2574 starget_for_each_device(starget, NULL, device_quiesce_fn);
2576 EXPORT_SYMBOL(scsi_target_quiesce);
2579 device_resume_fn(struct scsi_device *sdev, void *data)
2581 scsi_device_resume(sdev);
2585 scsi_target_resume(struct scsi_target *starget)
2587 starget_for_each_device(starget, NULL, device_resume_fn);
2589 EXPORT_SYMBOL(scsi_target_resume);
2592 * scsi_internal_device_block_nowait - try to transition to the SDEV_BLOCK state
2593 * @sdev: device to block
2595 * Pause SCSI command processing on the specified device. Does not sleep.
2597 * Returns zero if successful or a negative error code upon failure.
2600 * This routine transitions the device to the SDEV_BLOCK state (which must be
2601 * a legal transition). When the device is in this state, command processing
2602 * is paused until the device leaves the SDEV_BLOCK state. See also
2603 * scsi_internal_device_unblock_nowait().
2605 int scsi_internal_device_block_nowait(struct scsi_device *sdev)
2607 struct request_queue *q = sdev->request_queue;
2610 err = scsi_device_set_state(sdev, SDEV_BLOCK);
2612 err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2619 * The device has transitioned to SDEV_BLOCK. Stop the
2620 * block layer from calling the midlayer with this device's
2623 blk_mq_quiesce_queue_nowait(q);
2626 EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait);
2629 * scsi_internal_device_block - try to transition to the SDEV_BLOCK state
2630 * @sdev: device to block
2632 * Pause SCSI command processing on the specified device and wait until all
2633 * ongoing scsi_request_fn() / scsi_queue_rq() calls have finished. May sleep.
2635 * Returns zero if successful or a negative error code upon failure.
2638 * This routine transitions the device to the SDEV_BLOCK state (which must be
2639 * a legal transition). When the device is in this state, command processing
2640 * is paused until the device leaves the SDEV_BLOCK state. See also
2641 * scsi_internal_device_unblock().
2643 * To do: avoid that scsi_send_eh_cmnd() calls queuecommand() after
2644 * scsi_internal_device_block() has blocked a SCSI device and also
2645 * remove the rport mutex lock and unlock calls from srp_queuecommand().
2647 static int scsi_internal_device_block(struct scsi_device *sdev)
2649 struct request_queue *q = sdev->request_queue;
2652 mutex_lock(&sdev->state_mutex);
2653 err = scsi_internal_device_block_nowait(sdev);
2655 blk_mq_quiesce_queue(q);
2656 mutex_unlock(&sdev->state_mutex);
2661 void scsi_start_queue(struct scsi_device *sdev)
2663 struct request_queue *q = sdev->request_queue;
2665 blk_mq_unquiesce_queue(q);
2669 * scsi_internal_device_unblock_nowait - resume a device after a block request
2670 * @sdev: device to resume
2671 * @new_state: state to set the device to after unblocking
2673 * Restart the device queue for a previously suspended SCSI device. Does not
2676 * Returns zero if successful or a negative error code upon failure.
2679 * This routine transitions the device to the SDEV_RUNNING state or to one of
2680 * the offline states (which must be a legal transition) allowing the midlayer
2681 * to goose the queue for this device.
2683 int scsi_internal_device_unblock_nowait(struct scsi_device *sdev,
2684 enum scsi_device_state new_state)
2687 * Try to transition the scsi device to SDEV_RUNNING or one of the
2688 * offlined states and goose the device queue if successful.
2690 switch (sdev->sdev_state) {
2692 case SDEV_TRANSPORT_OFFLINE:
2693 sdev->sdev_state = new_state;
2695 case SDEV_CREATED_BLOCK:
2696 if (new_state == SDEV_TRANSPORT_OFFLINE ||
2697 new_state == SDEV_OFFLINE)
2698 sdev->sdev_state = new_state;
2700 sdev->sdev_state = SDEV_CREATED;
2708 scsi_start_queue(sdev);
2712 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock_nowait);
2715 * scsi_internal_device_unblock - resume a device after a block request
2716 * @sdev: device to resume
2717 * @new_state: state to set the device to after unblocking
2719 * Restart the device queue for a previously suspended SCSI device. May sleep.
2721 * Returns zero if successful or a negative error code upon failure.
2724 * This routine transitions the device to the SDEV_RUNNING state or to one of
2725 * the offline states (which must be a legal transition) allowing the midlayer
2726 * to goose the queue for this device.
2728 static int scsi_internal_device_unblock(struct scsi_device *sdev,
2729 enum scsi_device_state new_state)
2733 mutex_lock(&sdev->state_mutex);
2734 ret = scsi_internal_device_unblock_nowait(sdev, new_state);
2735 mutex_unlock(&sdev->state_mutex);
2741 device_block(struct scsi_device *sdev, void *data)
2743 scsi_internal_device_block(sdev);
2747 target_block(struct device *dev, void *data)
2749 if (scsi_is_target_device(dev))
2750 starget_for_each_device(to_scsi_target(dev), NULL,
2756 scsi_target_block(struct device *dev)
2758 if (scsi_is_target_device(dev))
2759 starget_for_each_device(to_scsi_target(dev), NULL,
2762 device_for_each_child(dev, NULL, target_block);
2764 EXPORT_SYMBOL_GPL(scsi_target_block);
2767 device_unblock(struct scsi_device *sdev, void *data)
2769 scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
2773 target_unblock(struct device *dev, void *data)
2775 if (scsi_is_target_device(dev))
2776 starget_for_each_device(to_scsi_target(dev), data,
2782 scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
2784 if (scsi_is_target_device(dev))
2785 starget_for_each_device(to_scsi_target(dev), &new_state,
2788 device_for_each_child(dev, &new_state, target_unblock);
2790 EXPORT_SYMBOL_GPL(scsi_target_unblock);
2793 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
2794 * @sgl: scatter-gather list
2795 * @sg_count: number of segments in sg
2796 * @offset: offset in bytes into sg, on return offset into the mapped area
2797 * @len: bytes to map, on return number of bytes mapped
2799 * Returns virtual address of the start of the mapped page
2801 void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
2802 size_t *offset, size_t *len)
2805 size_t sg_len = 0, len_complete = 0;
2806 struct scatterlist *sg;
2809 WARN_ON(!irqs_disabled());
2811 for_each_sg(sgl, sg, sg_count, i) {
2812 len_complete = sg_len; /* Complete sg-entries */
2813 sg_len += sg->length;
2814 if (sg_len > *offset)
2818 if (unlikely(i == sg_count)) {
2819 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
2821 __func__, sg_len, *offset, sg_count);
2826 /* Offset starting from the beginning of first page in this sg-entry */
2827 *offset = *offset - len_complete + sg->offset;
2829 /* Assumption: contiguous pages can be accessed as "page + i" */
2830 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
2831 *offset &= ~PAGE_MASK;
2833 /* Bytes in this sg-entry from *offset to the end of the page */
2834 sg_len = PAGE_SIZE - *offset;
2838 return kmap_atomic(page);
2840 EXPORT_SYMBOL(scsi_kmap_atomic_sg);
2843 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
2844 * @virt: virtual address to be unmapped
2846 void scsi_kunmap_atomic_sg(void *virt)
2848 kunmap_atomic(virt);
2850 EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
2852 void sdev_disable_disk_events(struct scsi_device *sdev)
2854 atomic_inc(&sdev->disk_events_disable_depth);
2856 EXPORT_SYMBOL(sdev_disable_disk_events);
2858 void sdev_enable_disk_events(struct scsi_device *sdev)
2860 if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0))
2862 atomic_dec(&sdev->disk_events_disable_depth);
2864 EXPORT_SYMBOL(sdev_enable_disk_events);
2867 * scsi_vpd_lun_id - return a unique device identification
2868 * @sdev: SCSI device
2869 * @id: buffer for the identification
2870 * @id_len: length of the buffer
2872 * Copies a unique device identification into @id based
2873 * on the information in the VPD page 0x83 of the device.
2874 * The string will be formatted as a SCSI name string.
2876 * Returns the length of the identification or error on failure.
2877 * If the identifier is longer than the supplied buffer the actual
2878 * identifier length is returned and the buffer is not zero-padded.
2880 int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len)
2882 u8 cur_id_type = 0xff;
2884 const unsigned char *d, *cur_id_str;
2885 const struct scsi_vpd *vpd_pg83;
2886 int id_size = -EINVAL;
2889 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
2896 * Look for the correct descriptor.
2897 * Order of preference for lun descriptor:
2898 * - SCSI name string
2899 * - NAA IEEE Registered Extended
2900 * - EUI-64 based 16-byte
2901 * - EUI-64 based 12-byte
2902 * - NAA IEEE Registered
2903 * - NAA IEEE Extended
2905 * as longer descriptors reduce the likelyhood
2906 * of identification clashes.
2909 /* The id string must be at least 20 bytes + terminating NULL byte */
2915 memset(id, 0, id_len);
2916 d = vpd_pg83->data + 4;
2917 while (d < vpd_pg83->data + vpd_pg83->len) {
2918 /* Skip designators not referring to the LUN */
2919 if ((d[1] & 0x30) != 0x00)
2922 switch (d[1] & 0xf) {
2925 if (cur_id_size > d[3])
2927 /* Prefer anything */
2928 if (cur_id_type > 0x01 && cur_id_type != 0xff)
2931 if (cur_id_size + 4 > id_len)
2932 cur_id_size = id_len - 4;
2934 cur_id_type = d[1] & 0xf;
2935 id_size = snprintf(id, id_len, "t10.%*pE",
2936 cur_id_size, cur_id_str);
2940 if (cur_id_size > d[3])
2942 /* Prefer NAA IEEE Registered Extended */
2943 if (cur_id_type == 0x3 &&
2944 cur_id_size == d[3])
2948 cur_id_type = d[1] & 0xf;
2949 switch (cur_id_size) {
2951 id_size = snprintf(id, id_len,
2956 id_size = snprintf(id, id_len,
2961 id_size = snprintf(id, id_len,
2972 if (cur_id_size > d[3])
2976 cur_id_type = d[1] & 0xf;
2977 switch (cur_id_size) {
2979 id_size = snprintf(id, id_len,
2984 id_size = snprintf(id, id_len,
2994 /* SCSI name string */
2995 if (cur_id_size + 4 > d[3])
2997 /* Prefer others for truncated descriptor */
2998 if (cur_id_size && d[3] > id_len)
3000 cur_id_size = id_size = d[3];
3002 cur_id_type = d[1] & 0xf;
3003 if (cur_id_size >= id_len)
3004 cur_id_size = id_len - 1;
3005 memcpy(id, cur_id_str, cur_id_size);
3006 /* Decrease priority for truncated descriptor */
3007 if (cur_id_size != id_size)
3020 EXPORT_SYMBOL(scsi_vpd_lun_id);
3023 * scsi_vpd_tpg_id - return a target port group identifier
3024 * @sdev: SCSI device
3026 * Returns the Target Port Group identifier from the information
3027 * froom VPD page 0x83 of the device.
3029 * Returns the identifier or error on failure.
3031 int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id)
3033 const unsigned char *d;
3034 const struct scsi_vpd *vpd_pg83;
3035 int group_id = -EAGAIN, rel_port = -1;
3038 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3044 d = vpd_pg83->data + 4;
3045 while (d < vpd_pg83->data + vpd_pg83->len) {
3046 switch (d[1] & 0xf) {
3048 /* Relative target port */
3049 rel_port = get_unaligned_be16(&d[6]);
3052 /* Target port group */
3053 group_id = get_unaligned_be16(&d[6]);
3062 if (group_id >= 0 && rel_id && rel_port != -1)
3067 EXPORT_SYMBOL(scsi_vpd_tpg_id);