1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 1999 Eric Youngdale
4 * Copyright (C) 2014 Christoph Hellwig
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.
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>
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>
37 #include <trace/events/scsi.h>
39 #include "scsi_debugfs.h"
40 #include "scsi_priv.h"
41 #include "scsi_logging.h"
44 * Size of integrity metadata is usually small, 1 inline sg should
47 #ifdef CONFIG_ARCH_NO_SG_CHAIN
48 #define SCSI_INLINE_PROT_SG_CNT 0
49 #define SCSI_INLINE_SG_CNT 0
51 #define SCSI_INLINE_PROT_SG_CNT 1
52 #define SCSI_INLINE_SG_CNT 2
55 static struct kmem_cache *scsi_sdb_cache;
56 static struct kmem_cache *scsi_sense_cache;
57 static struct kmem_cache *scsi_sense_isadma_cache;
58 static DEFINE_MUTEX(scsi_sense_cache_mutex);
60 static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd);
62 static inline struct kmem_cache *
63 scsi_select_sense_cache(bool unchecked_isa_dma)
65 return unchecked_isa_dma ? scsi_sense_isadma_cache : scsi_sense_cache;
68 static void scsi_free_sense_buffer(bool unchecked_isa_dma,
69 unsigned char *sense_buffer)
71 kmem_cache_free(scsi_select_sense_cache(unchecked_isa_dma),
75 static unsigned char *scsi_alloc_sense_buffer(bool unchecked_isa_dma,
76 gfp_t gfp_mask, int numa_node)
78 return kmem_cache_alloc_node(scsi_select_sense_cache(unchecked_isa_dma),
82 int scsi_init_sense_cache(struct Scsi_Host *shost)
84 struct kmem_cache *cache;
87 mutex_lock(&scsi_sense_cache_mutex);
88 cache = scsi_select_sense_cache(shost->unchecked_isa_dma);
92 if (shost->unchecked_isa_dma) {
93 scsi_sense_isadma_cache =
94 kmem_cache_create("scsi_sense_cache(DMA)",
95 SCSI_SENSE_BUFFERSIZE, 0,
96 SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA, NULL);
97 if (!scsi_sense_isadma_cache)
101 kmem_cache_create_usercopy("scsi_sense_cache",
102 SCSI_SENSE_BUFFERSIZE, 0, SLAB_HWCACHE_ALIGN,
103 0, SCSI_SENSE_BUFFERSIZE, NULL);
104 if (!scsi_sense_cache)
108 mutex_unlock(&scsi_sense_cache_mutex);
113 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
114 * not change behaviour from the previous unplug mechanism, experimentation
115 * may prove this needs changing.
117 #define SCSI_QUEUE_DELAY 3
120 scsi_set_blocked(struct scsi_cmnd *cmd, int reason)
122 struct Scsi_Host *host = cmd->device->host;
123 struct scsi_device *device = cmd->device;
124 struct scsi_target *starget = scsi_target(device);
127 * Set the appropriate busy bit for the device/host.
129 * If the host/device isn't busy, assume that something actually
130 * completed, and that we should be able to queue a command now.
132 * Note that the prior mid-layer assumption that any host could
133 * always queue at least one command is now broken. The mid-layer
134 * will implement a user specifiable stall (see
135 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
136 * if a command is requeued with no other commands outstanding
137 * either for the device or for the host.
140 case SCSI_MLQUEUE_HOST_BUSY:
141 atomic_set(&host->host_blocked, host->max_host_blocked);
143 case SCSI_MLQUEUE_DEVICE_BUSY:
144 case SCSI_MLQUEUE_EH_RETRY:
145 atomic_set(&device->device_blocked,
146 device->max_device_blocked);
148 case SCSI_MLQUEUE_TARGET_BUSY:
149 atomic_set(&starget->target_blocked,
150 starget->max_target_blocked);
155 static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd)
157 if (cmd->request->rq_flags & RQF_DONTPREP) {
158 cmd->request->rq_flags &= ~RQF_DONTPREP;
159 scsi_mq_uninit_cmd(cmd);
163 blk_mq_requeue_request(cmd->request, true);
167 * __scsi_queue_insert - private queue insertion
168 * @cmd: The SCSI command being requeued
169 * @reason: The reason for the requeue
170 * @unbusy: Whether the queue should be unbusied
172 * This is a private queue insertion. The public interface
173 * scsi_queue_insert() always assumes the queue should be unbusied
174 * because it's always called before the completion. This function is
175 * for a requeue after completion, which should only occur in this
178 static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy)
180 struct scsi_device *device = cmd->device;
182 SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd,
183 "Inserting command %p into mlqueue\n", cmd));
185 scsi_set_blocked(cmd, reason);
188 * Decrement the counters, since these commands are no longer
189 * active on the host/device.
192 scsi_device_unbusy(device, cmd);
195 * Requeue this command. It will go before all other commands
196 * that are already in the queue. Schedule requeue work under
197 * lock such that the kblockd_schedule_work() call happens
198 * before blk_cleanup_queue() finishes.
202 blk_mq_requeue_request(cmd->request, true);
206 * Function: scsi_queue_insert()
208 * Purpose: Insert a command in the midlevel queue.
210 * Arguments: cmd - command that we are adding to queue.
211 * reason - why we are inserting command to queue.
213 * Lock status: Assumed that lock is not held upon entry.
217 * Notes: We do this for one of two cases. Either the host is busy
218 * and it cannot accept any more commands for the time being,
219 * or the device returned QUEUE_FULL and can accept no more
221 * Notes: This could be called either from an interrupt context or a
222 * normal process context.
224 void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
226 __scsi_queue_insert(cmd, reason, true);
231 * __scsi_execute - insert request and wait for the result
234 * @data_direction: data direction
235 * @buffer: data buffer
236 * @bufflen: len of buffer
237 * @sense: optional sense buffer
238 * @sshdr: optional decoded sense header
239 * @timeout: request timeout in seconds
240 * @retries: number of times to retry request
241 * @flags: flags for ->cmd_flags
242 * @rq_flags: flags for ->rq_flags
243 * @resid: optional residual length
245 * Returns the scsi_cmnd result field if a command was executed, or a negative
246 * Linux error code if we didn't get that far.
248 int __scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
249 int data_direction, void *buffer, unsigned bufflen,
250 unsigned char *sense, struct scsi_sense_hdr *sshdr,
251 int timeout, int retries, u64 flags, req_flags_t rq_flags,
255 struct scsi_request *rq;
256 int ret = DRIVER_ERROR << 24;
258 req = blk_get_request(sdev->request_queue,
259 data_direction == DMA_TO_DEVICE ?
260 REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, BLK_MQ_REQ_PREEMPT);
265 if (bufflen && blk_rq_map_kern(sdev->request_queue, req,
266 buffer, bufflen, GFP_NOIO))
269 rq->cmd_len = COMMAND_SIZE(cmd[0]);
270 memcpy(rq->cmd, cmd, rq->cmd_len);
271 rq->retries = retries;
272 req->timeout = timeout;
273 req->cmd_flags |= flags;
274 req->rq_flags |= rq_flags | RQF_QUIET;
277 * head injection *required* here otherwise quiesce won't work
279 blk_execute_rq(req->q, NULL, req, 1);
282 * Some devices (USB mass-storage in particular) may transfer
283 * garbage data together with a residue indicating that the data
284 * is invalid. Prevent the garbage from being misinterpreted
285 * and prevent security leaks by zeroing out the excess data.
287 if (unlikely(rq->resid_len > 0 && rq->resid_len <= bufflen))
288 memset(buffer + (bufflen - rq->resid_len), 0, rq->resid_len);
291 *resid = rq->resid_len;
292 if (sense && rq->sense_len)
293 memcpy(sense, rq->sense, SCSI_SENSE_BUFFERSIZE);
295 scsi_normalize_sense(rq->sense, rq->sense_len, sshdr);
298 blk_put_request(req);
302 EXPORT_SYMBOL(__scsi_execute);
305 * Function: scsi_init_cmd_errh()
307 * Purpose: Initialize cmd fields related to error handling.
309 * Arguments: cmd - command that is ready to be queued.
311 * Notes: This function has the job of initializing a number of
312 * fields related to error handling. Typically this will
313 * be called once for each command, as required.
315 static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
317 scsi_set_resid(cmd, 0);
318 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
319 if (cmd->cmd_len == 0)
320 cmd->cmd_len = scsi_command_size(cmd->cmnd);
324 * Wake up the error handler if necessary. Avoid as follows that the error
325 * handler is not woken up if host in-flight requests number ==
326 * shost->host_failed: use call_rcu() in scsi_eh_scmd_add() in combination
327 * with an RCU read lock in this function to ensure that this function in
328 * its entirety either finishes before scsi_eh_scmd_add() increases the
329 * host_failed counter or that it notices the shost state change made by
330 * scsi_eh_scmd_add().
332 static void scsi_dec_host_busy(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
337 __clear_bit(SCMD_STATE_INFLIGHT, &cmd->state);
338 if (unlikely(scsi_host_in_recovery(shost))) {
339 spin_lock_irqsave(shost->host_lock, flags);
340 if (shost->host_failed || shost->host_eh_scheduled)
341 scsi_eh_wakeup(shost);
342 spin_unlock_irqrestore(shost->host_lock, flags);
347 void scsi_device_unbusy(struct scsi_device *sdev, struct scsi_cmnd *cmd)
349 struct Scsi_Host *shost = sdev->host;
350 struct scsi_target *starget = scsi_target(sdev);
352 scsi_dec_host_busy(shost, cmd);
354 if (starget->can_queue > 0)
355 atomic_dec(&starget->target_busy);
357 atomic_dec(&sdev->device_busy);
360 static void scsi_kick_queue(struct request_queue *q)
362 blk_mq_run_hw_queues(q, false);
366 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
367 * and call blk_run_queue for all the scsi_devices on the target -
368 * including current_sdev first.
370 * Called with *no* scsi locks held.
372 static void scsi_single_lun_run(struct scsi_device *current_sdev)
374 struct Scsi_Host *shost = current_sdev->host;
375 struct scsi_device *sdev, *tmp;
376 struct scsi_target *starget = scsi_target(current_sdev);
379 spin_lock_irqsave(shost->host_lock, flags);
380 starget->starget_sdev_user = NULL;
381 spin_unlock_irqrestore(shost->host_lock, flags);
384 * Call blk_run_queue for all LUNs on the target, starting with
385 * current_sdev. We race with others (to set starget_sdev_user),
386 * but in most cases, we will be first. Ideally, each LU on the
387 * target would get some limited time or requests on the target.
389 scsi_kick_queue(current_sdev->request_queue);
391 spin_lock_irqsave(shost->host_lock, flags);
392 if (starget->starget_sdev_user)
394 list_for_each_entry_safe(sdev, tmp, &starget->devices,
395 same_target_siblings) {
396 if (sdev == current_sdev)
398 if (scsi_device_get(sdev))
401 spin_unlock_irqrestore(shost->host_lock, flags);
402 scsi_kick_queue(sdev->request_queue);
403 spin_lock_irqsave(shost->host_lock, flags);
405 scsi_device_put(sdev);
408 spin_unlock_irqrestore(shost->host_lock, flags);
411 static inline bool scsi_device_is_busy(struct scsi_device *sdev)
413 if (atomic_read(&sdev->device_busy) >= sdev->queue_depth)
415 if (atomic_read(&sdev->device_blocked) > 0)
420 static inline bool scsi_target_is_busy(struct scsi_target *starget)
422 if (starget->can_queue > 0) {
423 if (atomic_read(&starget->target_busy) >= starget->can_queue)
425 if (atomic_read(&starget->target_blocked) > 0)
431 static inline bool scsi_host_is_busy(struct Scsi_Host *shost)
433 if (atomic_read(&shost->host_blocked) > 0)
435 if (shost->host_self_blocked)
440 static void scsi_starved_list_run(struct Scsi_Host *shost)
442 LIST_HEAD(starved_list);
443 struct scsi_device *sdev;
446 spin_lock_irqsave(shost->host_lock, flags);
447 list_splice_init(&shost->starved_list, &starved_list);
449 while (!list_empty(&starved_list)) {
450 struct request_queue *slq;
453 * As long as shost is accepting commands and we have
454 * starved queues, call blk_run_queue. scsi_request_fn
455 * drops the queue_lock and can add us back to the
458 * host_lock protects the starved_list and starved_entry.
459 * scsi_request_fn must get the host_lock before checking
460 * or modifying starved_list or starved_entry.
462 if (scsi_host_is_busy(shost))
465 sdev = list_entry(starved_list.next,
466 struct scsi_device, starved_entry);
467 list_del_init(&sdev->starved_entry);
468 if (scsi_target_is_busy(scsi_target(sdev))) {
469 list_move_tail(&sdev->starved_entry,
470 &shost->starved_list);
475 * Once we drop the host lock, a racing scsi_remove_device()
476 * call may remove the sdev from the starved list and destroy
477 * it and the queue. Mitigate by taking a reference to the
478 * queue and never touching the sdev again after we drop the
479 * host lock. Note: if __scsi_remove_device() invokes
480 * blk_cleanup_queue() before the queue is run from this
481 * function then blk_run_queue() will return immediately since
482 * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING.
484 slq = sdev->request_queue;
485 if (!blk_get_queue(slq))
487 spin_unlock_irqrestore(shost->host_lock, flags);
489 scsi_kick_queue(slq);
492 spin_lock_irqsave(shost->host_lock, flags);
494 /* put any unprocessed entries back */
495 list_splice(&starved_list, &shost->starved_list);
496 spin_unlock_irqrestore(shost->host_lock, flags);
500 * Function: scsi_run_queue()
502 * Purpose: Select a proper request queue to serve next
504 * Arguments: q - last request's queue
508 * Notes: The previous command was completely finished, start
509 * a new one if possible.
511 static void scsi_run_queue(struct request_queue *q)
513 struct scsi_device *sdev = q->queuedata;
515 if (scsi_target(sdev)->single_lun)
516 scsi_single_lun_run(sdev);
517 if (!list_empty(&sdev->host->starved_list))
518 scsi_starved_list_run(sdev->host);
520 blk_mq_run_hw_queues(q, false);
523 void scsi_requeue_run_queue(struct work_struct *work)
525 struct scsi_device *sdev;
526 struct request_queue *q;
528 sdev = container_of(work, struct scsi_device, requeue_work);
529 q = sdev->request_queue;
533 void scsi_run_host_queues(struct Scsi_Host *shost)
535 struct scsi_device *sdev;
537 shost_for_each_device(sdev, shost)
538 scsi_run_queue(sdev->request_queue);
541 static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
543 if (!blk_rq_is_passthrough(cmd->request)) {
544 struct scsi_driver *drv = scsi_cmd_to_driver(cmd);
546 if (drv->uninit_command)
547 drv->uninit_command(cmd);
551 static void scsi_mq_free_sgtables(struct scsi_cmnd *cmd)
553 if (cmd->sdb.table.nents)
554 sg_free_table_chained(&cmd->sdb.table,
556 if (scsi_prot_sg_count(cmd))
557 sg_free_table_chained(&cmd->prot_sdb->table,
558 SCSI_INLINE_PROT_SG_CNT);
561 static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
563 scsi_mq_free_sgtables(cmd);
564 scsi_uninit_cmd(cmd);
567 /* Returns false when no more bytes to process, true if there are more */
568 static bool scsi_end_request(struct request *req, blk_status_t error,
571 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
572 struct scsi_device *sdev = cmd->device;
573 struct request_queue *q = sdev->request_queue;
575 if (blk_update_request(req, error, bytes))
578 if (blk_queue_add_random(q))
579 add_disk_randomness(req->rq_disk);
581 if (!blk_rq_is_scsi(req)) {
582 WARN_ON_ONCE(!(cmd->flags & SCMD_INITIALIZED));
583 cmd->flags &= ~SCMD_INITIALIZED;
587 * Calling rcu_barrier() is not necessary here because the
588 * SCSI error handler guarantees that the function called by
589 * call_rcu() has been called before scsi_end_request() is
592 destroy_rcu_head(&cmd->rcu);
595 * In the MQ case the command gets freed by __blk_mq_end_request,
596 * so we have to do all cleanup that depends on it earlier.
598 * We also can't kick the queues from irq context, so we
599 * will have to defer it to a workqueue.
601 scsi_mq_uninit_cmd(cmd);
604 * queue is still alive, so grab the ref for preventing it
605 * from being cleaned up during running queue.
607 percpu_ref_get(&q->q_usage_counter);
609 __blk_mq_end_request(req, error);
611 if (scsi_target(sdev)->single_lun ||
612 !list_empty(&sdev->host->starved_list))
613 kblockd_schedule_work(&sdev->requeue_work);
615 blk_mq_run_hw_queues(q, true);
617 percpu_ref_put(&q->q_usage_counter);
622 * scsi_result_to_blk_status - translate a SCSI result code into blk_status_t
624 * @result: scsi error code
626 * Translate a SCSI result code into a blk_status_t value. May reset the host
627 * byte of @cmd->result.
629 static blk_status_t scsi_result_to_blk_status(struct scsi_cmnd *cmd, int result)
631 switch (host_byte(result)) {
634 * Also check the other bytes than the status byte in result
635 * to handle the case when a SCSI LLD sets result to
636 * DRIVER_SENSE << 24 without setting SAM_STAT_CHECK_CONDITION.
638 if (scsi_status_is_good(result) && (result & ~0xff) == 0)
640 return BLK_STS_IOERR;
641 case DID_TRANSPORT_FAILFAST:
642 return BLK_STS_TRANSPORT;
643 case DID_TARGET_FAILURE:
644 set_host_byte(cmd, DID_OK);
645 return BLK_STS_TARGET;
646 case DID_NEXUS_FAILURE:
647 set_host_byte(cmd, DID_OK);
648 return BLK_STS_NEXUS;
649 case DID_ALLOC_FAILURE:
650 set_host_byte(cmd, DID_OK);
651 return BLK_STS_NOSPC;
652 case DID_MEDIUM_ERROR:
653 set_host_byte(cmd, DID_OK);
654 return BLK_STS_MEDIUM;
656 return BLK_STS_IOERR;
660 /* Helper for scsi_io_completion() when "reprep" action required. */
661 static void scsi_io_completion_reprep(struct scsi_cmnd *cmd,
662 struct request_queue *q)
664 /* A new command will be prepared and issued. */
665 scsi_mq_requeue_cmd(cmd);
668 /* Helper for scsi_io_completion() when special action required. */
669 static void scsi_io_completion_action(struct scsi_cmnd *cmd, int result)
671 struct request_queue *q = cmd->device->request_queue;
672 struct request *req = cmd->request;
674 enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,
675 ACTION_DELAYED_RETRY} action;
676 unsigned long wait_for = (cmd->allowed + 1) * req->timeout;
677 struct scsi_sense_hdr sshdr;
679 bool sense_current = true; /* false implies "deferred sense" */
680 blk_status_t blk_stat;
682 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
684 sense_current = !scsi_sense_is_deferred(&sshdr);
686 blk_stat = scsi_result_to_blk_status(cmd, result);
688 if (host_byte(result) == DID_RESET) {
689 /* Third party bus reset or reset for error recovery
690 * reasons. Just retry the command and see what
693 action = ACTION_RETRY;
694 } else if (sense_valid && sense_current) {
695 switch (sshdr.sense_key) {
697 if (cmd->device->removable) {
698 /* Detected disc change. Set a bit
699 * and quietly refuse further access.
701 cmd->device->changed = 1;
702 action = ACTION_FAIL;
704 /* Must have been a power glitch, or a
705 * bus reset. Could not have been a
706 * media change, so we just retry the
707 * command and see what happens.
709 action = ACTION_RETRY;
712 case ILLEGAL_REQUEST:
713 /* If we had an ILLEGAL REQUEST returned, then
714 * we may have performed an unsupported
715 * command. The only thing this should be
716 * would be a ten byte read where only a six
717 * byte read was supported. Also, on a system
718 * where READ CAPACITY failed, we may have
719 * read past the end of the disk.
721 if ((cmd->device->use_10_for_rw &&
722 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
723 (cmd->cmnd[0] == READ_10 ||
724 cmd->cmnd[0] == WRITE_10)) {
725 /* This will issue a new 6-byte command. */
726 cmd->device->use_10_for_rw = 0;
727 action = ACTION_REPREP;
728 } else if (sshdr.asc == 0x10) /* DIX */ {
729 action = ACTION_FAIL;
730 blk_stat = BLK_STS_PROTECTION;
731 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
732 } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
733 action = ACTION_FAIL;
734 blk_stat = BLK_STS_TARGET;
736 action = ACTION_FAIL;
738 case ABORTED_COMMAND:
739 action = ACTION_FAIL;
740 if (sshdr.asc == 0x10) /* DIF */
741 blk_stat = BLK_STS_PROTECTION;
744 /* If the device is in the process of becoming
745 * ready, or has a temporary blockage, retry.
747 if (sshdr.asc == 0x04) {
748 switch (sshdr.ascq) {
749 case 0x01: /* becoming ready */
750 case 0x04: /* format in progress */
751 case 0x05: /* rebuild in progress */
752 case 0x06: /* recalculation in progress */
753 case 0x07: /* operation in progress */
754 case 0x08: /* Long write in progress */
755 case 0x09: /* self test in progress */
756 case 0x14: /* space allocation in progress */
757 case 0x1a: /* start stop unit in progress */
758 case 0x1b: /* sanitize in progress */
759 case 0x1d: /* configuration in progress */
760 case 0x24: /* depopulation in progress */
761 action = ACTION_DELAYED_RETRY;
764 action = ACTION_FAIL;
768 action = ACTION_FAIL;
770 case VOLUME_OVERFLOW:
771 /* See SSC3rXX or current. */
772 action = ACTION_FAIL;
775 action = ACTION_FAIL;
779 action = ACTION_FAIL;
781 if (action != ACTION_FAIL &&
782 time_before(cmd->jiffies_at_alloc + wait_for, jiffies))
783 action = ACTION_FAIL;
787 /* Give up and fail the remainder of the request */
788 if (!(req->rq_flags & RQF_QUIET)) {
789 static DEFINE_RATELIMIT_STATE(_rs,
790 DEFAULT_RATELIMIT_INTERVAL,
791 DEFAULT_RATELIMIT_BURST);
793 if (unlikely(scsi_logging_level))
795 SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
796 SCSI_LOG_MLCOMPLETE_BITS);
799 * if logging is enabled the failure will be printed
800 * in scsi_log_completion(), so avoid duplicate messages
802 if (!level && __ratelimit(&_rs)) {
803 scsi_print_result(cmd, NULL, FAILED);
804 if (driver_byte(result) == DRIVER_SENSE)
805 scsi_print_sense(cmd);
806 scsi_print_command(cmd);
809 if (!scsi_end_request(req, blk_stat, blk_rq_err_bytes(req)))
813 scsi_io_completion_reprep(cmd, q);
816 /* Retry the same command immediately */
817 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, false);
819 case ACTION_DELAYED_RETRY:
820 /* Retry the same command after a delay */
821 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, false);
827 * Helper for scsi_io_completion() when cmd->result is non-zero. Returns a
828 * new result that may suppress further error checking. Also modifies
829 * *blk_statp in some cases.
831 static int scsi_io_completion_nz_result(struct scsi_cmnd *cmd, int result,
832 blk_status_t *blk_statp)
835 bool sense_current = true; /* false implies "deferred sense" */
836 struct request *req = cmd->request;
837 struct scsi_sense_hdr sshdr;
839 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
841 sense_current = !scsi_sense_is_deferred(&sshdr);
843 if (blk_rq_is_passthrough(req)) {
846 * SG_IO wants current and deferred errors
848 scsi_req(req)->sense_len =
849 min(8 + cmd->sense_buffer[7],
850 SCSI_SENSE_BUFFERSIZE);
853 *blk_statp = scsi_result_to_blk_status(cmd, result);
854 } else if (blk_rq_bytes(req) == 0 && sense_current) {
856 * Flush commands do not transfers any data, and thus cannot use
857 * good_bytes != blk_rq_bytes(req) as the signal for an error.
858 * This sets *blk_statp explicitly for the problem case.
860 *blk_statp = scsi_result_to_blk_status(cmd, result);
863 * Recovered errors need reporting, but they're always treated as
864 * success, so fiddle the result code here. For passthrough requests
865 * we already took a copy of the original into sreq->result which
866 * is what gets returned to the user
868 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
869 bool do_print = true;
871 * if ATA PASS-THROUGH INFORMATION AVAILABLE [0x0, 0x1d]
872 * skip print since caller wants ATA registers. Only occurs
873 * on SCSI ATA PASS_THROUGH commands when CK_COND=1
875 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
877 else if (req->rq_flags & RQF_QUIET)
880 scsi_print_sense(cmd);
882 /* for passthrough, *blk_statp may be set */
883 *blk_statp = BLK_STS_OK;
886 * Another corner case: the SCSI status byte is non-zero but 'good'.
887 * Example: PRE-FETCH command returns SAM_STAT_CONDITION_MET when
888 * it is able to fit nominated LBs in its cache (and SAM_STAT_GOOD
889 * if it can't fit). Treat SAM_STAT_CONDITION_MET and the related
890 * intermediate statuses (both obsolete in SAM-4) as good.
892 if (status_byte(result) && scsi_status_is_good(result)) {
894 *blk_statp = BLK_STS_OK;
900 * Function: scsi_io_completion()
902 * Purpose: Completion processing for block device I/O requests.
904 * Arguments: cmd - command that is finished.
906 * Lock status: Assumed that no lock is held upon entry.
910 * Notes: We will finish off the specified number of sectors. If we
911 * are done, the command block will be released and the queue
912 * function will be goosed. If we are not done then we have to
913 * figure out what to do next:
915 * a) We can call scsi_requeue_command(). The request
916 * will be unprepared and put back on the queue. Then
917 * a new command will be created for it. This should
918 * be used if we made forward progress, or if we want
919 * to switch from READ(10) to READ(6) for example.
921 * b) We can call __scsi_queue_insert(). The request will
922 * be put back on the queue and retried using the same
923 * command as before, possibly after a delay.
925 * c) We can call scsi_end_request() with blk_stat other than
926 * BLK_STS_OK, to fail the remainder of the request.
928 void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
930 int result = cmd->result;
931 struct request_queue *q = cmd->device->request_queue;
932 struct request *req = cmd->request;
933 blk_status_t blk_stat = BLK_STS_OK;
935 if (unlikely(result)) /* a nz result may or may not be an error */
936 result = scsi_io_completion_nz_result(cmd, result, &blk_stat);
938 if (unlikely(blk_rq_is_passthrough(req))) {
940 * scsi_result_to_blk_status may have reset the host_byte
942 scsi_req(req)->result = cmd->result;
946 * Next deal with any sectors which we were able to correctly
949 SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd,
950 "%u sectors total, %d bytes done.\n",
951 blk_rq_sectors(req), good_bytes));
954 * Next deal with any sectors which we were able to correctly
955 * handle. Failed, zero length commands always need to drop down
956 * to retry code. Fast path should return in this block.
958 if (likely(blk_rq_bytes(req) > 0 || blk_stat == BLK_STS_OK)) {
959 if (likely(!scsi_end_request(req, blk_stat, good_bytes)))
960 return; /* no bytes remaining */
963 /* Kill remainder if no retries. */
964 if (unlikely(blk_stat && scsi_noretry_cmd(cmd))) {
965 if (scsi_end_request(req, blk_stat, blk_rq_bytes(req)))
967 "Bytes remaining after failed, no-retry command");
972 * If there had been no error, but we have leftover bytes in the
973 * requeues just queue the command up again.
975 if (likely(result == 0))
976 scsi_io_completion_reprep(cmd, q);
978 scsi_io_completion_action(cmd, result);
981 static inline bool scsi_cmd_needs_dma_drain(struct scsi_device *sdev,
984 return sdev->dma_drain_len && blk_rq_is_passthrough(rq) &&
985 !op_is_write(req_op(rq)) &&
986 sdev->host->hostt->dma_need_drain(rq);
990 * Function: scsi_init_io()
992 * Purpose: SCSI I/O initialize function.
994 * Arguments: cmd - Command descriptor we wish to initialize
996 * Returns: BLK_STS_OK on success
997 * BLK_STS_RESOURCE if the failure is retryable
998 * BLK_STS_IOERR if the failure is fatal
1000 blk_status_t scsi_init_io(struct scsi_cmnd *cmd)
1002 struct scsi_device *sdev = cmd->device;
1003 struct request *rq = cmd->request;
1004 unsigned short nr_segs = blk_rq_nr_phys_segments(rq);
1005 struct scatterlist *last_sg = NULL;
1007 bool need_drain = scsi_cmd_needs_dma_drain(sdev, rq);
1010 if (WARN_ON_ONCE(!nr_segs))
1011 return BLK_STS_IOERR;
1014 * Make sure there is space for the drain. The driver must adjust
1015 * max_hw_segments to be prepared for this.
1021 * If sg table allocation fails, requeue request later.
1023 if (unlikely(sg_alloc_table_chained(&cmd->sdb.table, nr_segs,
1024 cmd->sdb.table.sgl, SCSI_INLINE_SG_CNT)))
1025 return BLK_STS_RESOURCE;
1028 * Next, walk the list, and fill in the addresses and sizes of
1031 count = __blk_rq_map_sg(rq->q, rq, cmd->sdb.table.sgl, &last_sg);
1033 if (blk_rq_bytes(rq) & rq->q->dma_pad_mask) {
1034 unsigned int pad_len =
1035 (rq->q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1;
1037 last_sg->length += pad_len;
1038 cmd->extra_len += pad_len;
1042 sg_unmark_end(last_sg);
1043 last_sg = sg_next(last_sg);
1044 sg_set_buf(last_sg, sdev->dma_drain_buf, sdev->dma_drain_len);
1045 sg_mark_end(last_sg);
1047 cmd->extra_len += sdev->dma_drain_len;
1051 BUG_ON(count > cmd->sdb.table.nents);
1052 cmd->sdb.table.nents = count;
1053 cmd->sdb.length = blk_rq_payload_bytes(rq);
1055 if (blk_integrity_rq(rq)) {
1056 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1059 if (WARN_ON_ONCE(!prot_sdb)) {
1061 * This can happen if someone (e.g. multipath)
1062 * queues a command to a device on an adapter
1063 * that does not support DIX.
1065 ret = BLK_STS_IOERR;
1066 goto out_free_sgtables;
1069 ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
1071 if (sg_alloc_table_chained(&prot_sdb->table, ivecs,
1072 prot_sdb->table.sgl,
1073 SCSI_INLINE_PROT_SG_CNT)) {
1074 ret = BLK_STS_RESOURCE;
1075 goto out_free_sgtables;
1078 count = blk_rq_map_integrity_sg(rq->q, rq->bio,
1079 prot_sdb->table.sgl);
1080 BUG_ON(count > ivecs);
1081 BUG_ON(count > queue_max_integrity_segments(rq->q));
1083 cmd->prot_sdb = prot_sdb;
1084 cmd->prot_sdb->table.nents = count;
1089 scsi_mq_free_sgtables(cmd);
1092 EXPORT_SYMBOL(scsi_init_io);
1095 * scsi_initialize_rq - initialize struct scsi_cmnd partially
1096 * @rq: Request associated with the SCSI command to be initialized.
1098 * This function initializes the members of struct scsi_cmnd that must be
1099 * initialized before request processing starts and that won't be
1100 * reinitialized if a SCSI command is requeued.
1102 * Called from inside blk_get_request() for pass-through requests and from
1103 * inside scsi_init_command() for filesystem requests.
1105 static void scsi_initialize_rq(struct request *rq)
1107 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1109 scsi_req_init(&cmd->req);
1110 init_rcu_head(&cmd->rcu);
1111 cmd->jiffies_at_alloc = jiffies;
1116 * Only called when the request isn't completed by SCSI, and not freed by
1119 static void scsi_cleanup_rq(struct request *rq)
1121 if (rq->rq_flags & RQF_DONTPREP) {
1122 scsi_mq_uninit_cmd(blk_mq_rq_to_pdu(rq));
1123 rq->rq_flags &= ~RQF_DONTPREP;
1127 /* Called before a request is prepared. See also scsi_mq_prep_fn(). */
1128 void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd)
1130 void *buf = cmd->sense_buffer;
1131 void *prot = cmd->prot_sdb;
1132 struct request *rq = blk_mq_rq_from_pdu(cmd);
1133 unsigned int flags = cmd->flags & SCMD_PRESERVED_FLAGS;
1134 unsigned long jiffies_at_alloc;
1135 int retries, to_clear;
1138 if (!blk_rq_is_scsi(rq) && !(flags & SCMD_INITIALIZED)) {
1139 flags |= SCMD_INITIALIZED;
1140 scsi_initialize_rq(rq);
1143 jiffies_at_alloc = cmd->jiffies_at_alloc;
1144 retries = cmd->retries;
1145 in_flight = test_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1147 * Zero out the cmd, except for the embedded scsi_request. Only clear
1148 * the driver-private command data if the LLD does not supply a
1149 * function to initialize that data.
1151 to_clear = sizeof(*cmd) - sizeof(cmd->req);
1152 if (!dev->host->hostt->init_cmd_priv)
1153 to_clear += dev->host->hostt->cmd_size;
1154 memset((char *)cmd + sizeof(cmd->req), 0, to_clear);
1157 cmd->sense_buffer = buf;
1158 cmd->prot_sdb = prot;
1160 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
1161 cmd->jiffies_at_alloc = jiffies_at_alloc;
1162 cmd->retries = retries;
1164 __set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1168 static blk_status_t scsi_setup_scsi_cmnd(struct scsi_device *sdev,
1169 struct request *req)
1171 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1174 * Passthrough requests may transfer data, in which case they must
1175 * a bio attached to them. Or they might contain a SCSI command
1176 * that does not transfer data, in which case they may optionally
1177 * submit a request without an attached bio.
1180 blk_status_t ret = scsi_init_io(cmd);
1181 if (unlikely(ret != BLK_STS_OK))
1184 BUG_ON(blk_rq_bytes(req));
1186 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1189 cmd->cmd_len = scsi_req(req)->cmd_len;
1190 cmd->cmnd = scsi_req(req)->cmd;
1191 cmd->transfersize = blk_rq_bytes(req);
1192 cmd->allowed = scsi_req(req)->retries;
1197 * Setup a normal block command. These are simple request from filesystems
1198 * that still need to be translated to SCSI CDBs from the ULD.
1200 static blk_status_t scsi_setup_fs_cmnd(struct scsi_device *sdev,
1201 struct request *req)
1203 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1205 if (unlikely(sdev->handler && sdev->handler->prep_fn)) {
1206 blk_status_t ret = sdev->handler->prep_fn(sdev, req);
1207 if (ret != BLK_STS_OK)
1211 cmd->cmnd = scsi_req(req)->cmd = scsi_req(req)->__cmd;
1212 memset(cmd->cmnd, 0, BLK_MAX_CDB);
1213 return scsi_cmd_to_driver(cmd)->init_command(cmd);
1216 static blk_status_t scsi_setup_cmnd(struct scsi_device *sdev,
1217 struct request *req)
1219 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1221 if (!blk_rq_bytes(req))
1222 cmd->sc_data_direction = DMA_NONE;
1223 else if (rq_data_dir(req) == WRITE)
1224 cmd->sc_data_direction = DMA_TO_DEVICE;
1226 cmd->sc_data_direction = DMA_FROM_DEVICE;
1228 if (blk_rq_is_scsi(req))
1229 return scsi_setup_scsi_cmnd(sdev, req);
1231 return scsi_setup_fs_cmnd(sdev, req);
1235 scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
1237 switch (sdev->sdev_state) {
1239 case SDEV_TRANSPORT_OFFLINE:
1241 * If the device is offline we refuse to process any
1242 * commands. The device must be brought online
1243 * before trying any recovery commands.
1245 if (!sdev->offline_already) {
1246 sdev->offline_already = true;
1247 sdev_printk(KERN_ERR, sdev,
1248 "rejecting I/O to offline device\n");
1250 return BLK_STS_IOERR;
1253 * If the device is fully deleted, we refuse to
1254 * process any commands as well.
1256 sdev_printk(KERN_ERR, sdev,
1257 "rejecting I/O to dead device\n");
1258 return BLK_STS_IOERR;
1260 case SDEV_CREATED_BLOCK:
1261 return BLK_STS_RESOURCE;
1264 * If the devices is blocked we defer normal commands.
1266 if (req && !(req->rq_flags & RQF_PREEMPT))
1267 return BLK_STS_RESOURCE;
1271 * For any other not fully online state we only allow
1272 * special commands. In particular any user initiated
1273 * command is not allowed.
1275 if (req && !(req->rq_flags & RQF_PREEMPT))
1276 return BLK_STS_IOERR;
1282 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1285 * Called with the queue_lock held.
1287 static inline int scsi_dev_queue_ready(struct request_queue *q,
1288 struct scsi_device *sdev)
1292 busy = atomic_inc_return(&sdev->device_busy) - 1;
1293 if (atomic_read(&sdev->device_blocked)) {
1298 * unblock after device_blocked iterates to zero
1300 if (atomic_dec_return(&sdev->device_blocked) > 0)
1302 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev,
1303 "unblocking device at zero depth\n"));
1306 if (busy >= sdev->queue_depth)
1311 atomic_dec(&sdev->device_busy);
1316 * scsi_target_queue_ready: checks if there we can send commands to target
1317 * @sdev: scsi device on starget to check.
1319 static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1320 struct scsi_device *sdev)
1322 struct scsi_target *starget = scsi_target(sdev);
1325 if (starget->single_lun) {
1326 spin_lock_irq(shost->host_lock);
1327 if (starget->starget_sdev_user &&
1328 starget->starget_sdev_user != sdev) {
1329 spin_unlock_irq(shost->host_lock);
1332 starget->starget_sdev_user = sdev;
1333 spin_unlock_irq(shost->host_lock);
1336 if (starget->can_queue <= 0)
1339 busy = atomic_inc_return(&starget->target_busy) - 1;
1340 if (atomic_read(&starget->target_blocked) > 0) {
1345 * unblock after target_blocked iterates to zero
1347 if (atomic_dec_return(&starget->target_blocked) > 0)
1350 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1351 "unblocking target at zero depth\n"));
1354 if (busy >= starget->can_queue)
1360 spin_lock_irq(shost->host_lock);
1361 list_move_tail(&sdev->starved_entry, &shost->starved_list);
1362 spin_unlock_irq(shost->host_lock);
1364 if (starget->can_queue > 0)
1365 atomic_dec(&starget->target_busy);
1370 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1371 * return 0. We must end up running the queue again whenever 0 is
1372 * returned, else IO can hang.
1374 static inline int scsi_host_queue_ready(struct request_queue *q,
1375 struct Scsi_Host *shost,
1376 struct scsi_device *sdev,
1377 struct scsi_cmnd *cmd)
1379 if (scsi_host_in_recovery(shost))
1382 if (atomic_read(&shost->host_blocked) > 0) {
1383 if (scsi_host_busy(shost) > 0)
1387 * unblock after host_blocked iterates to zero
1389 if (atomic_dec_return(&shost->host_blocked) > 0)
1393 shost_printk(KERN_INFO, shost,
1394 "unblocking host at zero depth\n"));
1397 if (shost->host_self_blocked)
1400 /* We're OK to process the command, so we can't be starved */
1401 if (!list_empty(&sdev->starved_entry)) {
1402 spin_lock_irq(shost->host_lock);
1403 if (!list_empty(&sdev->starved_entry))
1404 list_del_init(&sdev->starved_entry);
1405 spin_unlock_irq(shost->host_lock);
1408 __set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1413 spin_lock_irq(shost->host_lock);
1414 if (list_empty(&sdev->starved_entry))
1415 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1416 spin_unlock_irq(shost->host_lock);
1418 scsi_dec_host_busy(shost, cmd);
1423 * Busy state exporting function for request stacking drivers.
1425 * For efficiency, no lock is taken to check the busy state of
1426 * shost/starget/sdev, since the returned value is not guaranteed and
1427 * may be changed after request stacking drivers call the function,
1428 * regardless of taking lock or not.
1430 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1431 * needs to return 'not busy'. Otherwise, request stacking drivers
1432 * may hold requests forever.
1434 static bool scsi_mq_lld_busy(struct request_queue *q)
1436 struct scsi_device *sdev = q->queuedata;
1437 struct Scsi_Host *shost;
1439 if (blk_queue_dying(q))
1445 * Ignore host/starget busy state.
1446 * Since block layer does not have a concept of fairness across
1447 * multiple queues, congestion of host/starget needs to be handled
1450 if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
1456 static void scsi_softirq_done(struct request *rq)
1458 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1459 unsigned long wait_for = (cmd->allowed + 1) * rq->timeout;
1462 INIT_LIST_HEAD(&cmd->eh_entry);
1464 atomic_inc(&cmd->device->iodone_cnt);
1466 atomic_inc(&cmd->device->ioerr_cnt);
1468 disposition = scsi_decide_disposition(cmd);
1469 if (disposition != SUCCESS &&
1470 time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
1471 scmd_printk(KERN_ERR, cmd,
1472 "timing out command, waited %lus\n",
1474 disposition = SUCCESS;
1477 scsi_log_completion(cmd, disposition);
1479 switch (disposition) {
1481 scsi_finish_command(cmd);
1484 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
1486 case ADD_TO_MLQUEUE:
1487 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1490 scsi_eh_scmd_add(cmd);
1496 * scsi_dispatch_command - Dispatch a command to the low-level driver.
1497 * @cmd: command block we are dispatching.
1499 * Return: nonzero return request was rejected and device's queue needs to be
1502 static int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
1504 struct Scsi_Host *host = cmd->device->host;
1507 atomic_inc(&cmd->device->iorequest_cnt);
1509 /* check if the device is still usable */
1510 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
1511 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
1512 * returns an immediate error upwards, and signals
1513 * that the device is no longer present */
1514 cmd->result = DID_NO_CONNECT << 16;
1518 /* Check to see if the scsi lld made this device blocked. */
1519 if (unlikely(scsi_device_blocked(cmd->device))) {
1521 * in blocked state, the command is just put back on
1522 * the device queue. The suspend state has already
1523 * blocked the queue so future requests should not
1524 * occur until the device transitions out of the
1527 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1528 "queuecommand : device blocked\n"));
1529 return SCSI_MLQUEUE_DEVICE_BUSY;
1532 /* Store the LUN value in cmnd, if needed. */
1533 if (cmd->device->lun_in_cdb)
1534 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
1535 (cmd->device->lun << 5 & 0xe0);
1540 * Before we queue this command, check if the command
1541 * length exceeds what the host adapter can handle.
1543 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
1544 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1545 "queuecommand : command too long. "
1546 "cdb_size=%d host->max_cmd_len=%d\n",
1547 cmd->cmd_len, cmd->device->host->max_cmd_len));
1548 cmd->result = (DID_ABORT << 16);
1552 if (unlikely(host->shost_state == SHOST_DEL)) {
1553 cmd->result = (DID_NO_CONNECT << 16);
1558 trace_scsi_dispatch_cmd_start(cmd);
1559 rtn = host->hostt->queuecommand(host, cmd);
1561 trace_scsi_dispatch_cmd_error(cmd, rtn);
1562 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
1563 rtn != SCSI_MLQUEUE_TARGET_BUSY)
1564 rtn = SCSI_MLQUEUE_HOST_BUSY;
1566 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1567 "queuecommand : request rejected\n"));
1572 cmd->scsi_done(cmd);
1576 /* Size in bytes of the sg-list stored in the scsi-mq command-private data. */
1577 static unsigned int scsi_mq_inline_sgl_size(struct Scsi_Host *shost)
1579 return min_t(unsigned int, shost->sg_tablesize, SCSI_INLINE_SG_CNT) *
1580 sizeof(struct scatterlist);
1583 static blk_status_t scsi_mq_prep_fn(struct request *req)
1585 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1586 struct scsi_device *sdev = req->q->queuedata;
1587 struct Scsi_Host *shost = sdev->host;
1588 struct scatterlist *sg;
1590 scsi_init_command(sdev, cmd);
1593 cmd->tag = req->tag;
1594 cmd->prot_op = SCSI_PROT_NORMAL;
1596 sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
1597 cmd->sdb.table.sgl = sg;
1599 if (scsi_host_get_prot(shost)) {
1600 memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer));
1602 cmd->prot_sdb->table.sgl =
1603 (struct scatterlist *)(cmd->prot_sdb + 1);
1606 blk_mq_start_request(req);
1608 return scsi_setup_cmnd(sdev, req);
1611 static void scsi_mq_done(struct scsi_cmnd *cmd)
1613 if (unlikely(test_and_set_bit(SCMD_STATE_COMPLETE, &cmd->state)))
1615 trace_scsi_dispatch_cmd_done(cmd);
1618 * If the block layer didn't complete the request due to a timeout
1619 * injection, scsi must clear its internal completed state so that the
1620 * timeout handler will see it needs to escalate its own error
1623 if (unlikely(!blk_mq_complete_request(cmd->request)))
1624 clear_bit(SCMD_STATE_COMPLETE, &cmd->state);
1627 static void scsi_mq_put_budget(struct blk_mq_hw_ctx *hctx)
1629 struct request_queue *q = hctx->queue;
1630 struct scsi_device *sdev = q->queuedata;
1632 atomic_dec(&sdev->device_busy);
1635 static bool scsi_mq_get_budget(struct blk_mq_hw_ctx *hctx)
1637 struct request_queue *q = hctx->queue;
1638 struct scsi_device *sdev = q->queuedata;
1640 return scsi_dev_queue_ready(q, sdev);
1643 static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
1644 const struct blk_mq_queue_data *bd)
1646 struct request *req = bd->rq;
1647 struct request_queue *q = req->q;
1648 struct scsi_device *sdev = q->queuedata;
1649 struct Scsi_Host *shost = sdev->host;
1650 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1655 * If the device is not in running state we will reject some or all
1658 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
1659 ret = scsi_prep_state_check(sdev, req);
1660 if (ret != BLK_STS_OK)
1661 goto out_put_budget;
1664 ret = BLK_STS_RESOURCE;
1665 if (!scsi_target_queue_ready(shost, sdev))
1666 goto out_put_budget;
1667 if (!scsi_host_queue_ready(q, shost, sdev, cmd))
1668 goto out_dec_target_busy;
1670 if (!(req->rq_flags & RQF_DONTPREP)) {
1671 ret = scsi_mq_prep_fn(req);
1672 if (ret != BLK_STS_OK)
1673 goto out_dec_host_busy;
1674 req->rq_flags |= RQF_DONTPREP;
1676 clear_bit(SCMD_STATE_COMPLETE, &cmd->state);
1677 blk_mq_start_request(req);
1680 cmd->flags &= SCMD_PRESERVED_FLAGS;
1681 if (sdev->simple_tags)
1682 cmd->flags |= SCMD_TAGGED;
1684 cmd->flags |= SCMD_LAST;
1686 scsi_init_cmd_errh(cmd);
1687 cmd->scsi_done = scsi_mq_done;
1689 reason = scsi_dispatch_cmd(cmd);
1691 scsi_set_blocked(cmd, reason);
1692 ret = BLK_STS_RESOURCE;
1693 goto out_dec_host_busy;
1699 scsi_dec_host_busy(shost, cmd);
1700 out_dec_target_busy:
1701 if (scsi_target(sdev)->can_queue > 0)
1702 atomic_dec(&scsi_target(sdev)->target_busy);
1704 scsi_mq_put_budget(hctx);
1708 case BLK_STS_RESOURCE:
1709 case BLK_STS_ZONE_RESOURCE:
1710 if (atomic_read(&sdev->device_busy) ||
1711 scsi_device_blocked(sdev))
1712 ret = BLK_STS_DEV_RESOURCE;
1715 if (unlikely(!scsi_device_online(sdev)))
1716 scsi_req(req)->result = DID_NO_CONNECT << 16;
1718 scsi_req(req)->result = DID_ERROR << 16;
1720 * Make sure to release all allocated resources when
1721 * we hit an error, as we will never see this command
1724 if (req->rq_flags & RQF_DONTPREP)
1725 scsi_mq_uninit_cmd(cmd);
1731 static enum blk_eh_timer_return scsi_timeout(struct request *req,
1735 return BLK_EH_RESET_TIMER;
1736 return scsi_times_out(req);
1739 static int scsi_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
1740 unsigned int hctx_idx, unsigned int numa_node)
1742 struct Scsi_Host *shost = set->driver_data;
1743 const bool unchecked_isa_dma = shost->unchecked_isa_dma;
1744 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1745 struct scatterlist *sg;
1748 if (unchecked_isa_dma)
1749 cmd->flags |= SCMD_UNCHECKED_ISA_DMA;
1750 cmd->sense_buffer = scsi_alloc_sense_buffer(unchecked_isa_dma,
1751 GFP_KERNEL, numa_node);
1752 if (!cmd->sense_buffer)
1754 cmd->req.sense = cmd->sense_buffer;
1756 if (scsi_host_get_prot(shost)) {
1757 sg = (void *)cmd + sizeof(struct scsi_cmnd) +
1758 shost->hostt->cmd_size;
1759 cmd->prot_sdb = (void *)sg + scsi_mq_inline_sgl_size(shost);
1762 if (shost->hostt->init_cmd_priv) {
1763 ret = shost->hostt->init_cmd_priv(shost, cmd);
1765 scsi_free_sense_buffer(unchecked_isa_dma,
1772 static void scsi_mq_exit_request(struct blk_mq_tag_set *set, struct request *rq,
1773 unsigned int hctx_idx)
1775 struct Scsi_Host *shost = set->driver_data;
1776 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1778 if (shost->hostt->exit_cmd_priv)
1779 shost->hostt->exit_cmd_priv(shost, cmd);
1780 scsi_free_sense_buffer(cmd->flags & SCMD_UNCHECKED_ISA_DMA,
1784 static int scsi_map_queues(struct blk_mq_tag_set *set)
1786 struct Scsi_Host *shost = container_of(set, struct Scsi_Host, tag_set);
1788 if (shost->hostt->map_queues)
1789 return shost->hostt->map_queues(shost);
1790 return blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]);
1793 void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
1795 struct device *dev = shost->dma_dev;
1798 * this limit is imposed by hardware restrictions
1800 blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
1803 if (scsi_host_prot_dma(shost)) {
1804 shost->sg_prot_tablesize =
1805 min_not_zero(shost->sg_prot_tablesize,
1806 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
1807 BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
1808 blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
1811 if (dev->dma_mask) {
1812 shost->max_sectors = min_t(unsigned int, shost->max_sectors,
1813 dma_max_mapping_size(dev) >> SECTOR_SHIFT);
1815 blk_queue_max_hw_sectors(q, shost->max_sectors);
1816 if (shost->unchecked_isa_dma)
1817 blk_queue_bounce_limit(q, BLK_BOUNCE_ISA);
1818 blk_queue_segment_boundary(q, shost->dma_boundary);
1819 dma_set_seg_boundary(dev, shost->dma_boundary);
1821 blk_queue_max_segment_size(q, shost->max_segment_size);
1822 blk_queue_virt_boundary(q, shost->virt_boundary_mask);
1823 dma_set_max_seg_size(dev, queue_max_segment_size(q));
1826 * Set a reasonable default alignment: The larger of 32-byte (dword),
1827 * which is a common minimum for HBAs, and the minimum DMA alignment,
1828 * which is set by the platform.
1830 * Devices that require a bigger alignment can increase it later.
1832 blk_queue_dma_alignment(q, max(4, dma_get_cache_alignment()) - 1);
1834 EXPORT_SYMBOL_GPL(__scsi_init_queue);
1836 static const struct blk_mq_ops scsi_mq_ops_no_commit = {
1837 .get_budget = scsi_mq_get_budget,
1838 .put_budget = scsi_mq_put_budget,
1839 .queue_rq = scsi_queue_rq,
1840 .complete = scsi_softirq_done,
1841 .timeout = scsi_timeout,
1842 #ifdef CONFIG_BLK_DEBUG_FS
1843 .show_rq = scsi_show_rq,
1845 .init_request = scsi_mq_init_request,
1846 .exit_request = scsi_mq_exit_request,
1847 .initialize_rq_fn = scsi_initialize_rq,
1848 .cleanup_rq = scsi_cleanup_rq,
1849 .busy = scsi_mq_lld_busy,
1850 .map_queues = scsi_map_queues,
1854 static void scsi_commit_rqs(struct blk_mq_hw_ctx *hctx)
1856 struct request_queue *q = hctx->queue;
1857 struct scsi_device *sdev = q->queuedata;
1858 struct Scsi_Host *shost = sdev->host;
1860 shost->hostt->commit_rqs(shost, hctx->queue_num);
1863 static const struct blk_mq_ops scsi_mq_ops = {
1864 .get_budget = scsi_mq_get_budget,
1865 .put_budget = scsi_mq_put_budget,
1866 .queue_rq = scsi_queue_rq,
1867 .commit_rqs = scsi_commit_rqs,
1868 .complete = scsi_softirq_done,
1869 .timeout = scsi_timeout,
1870 #ifdef CONFIG_BLK_DEBUG_FS
1871 .show_rq = scsi_show_rq,
1873 .init_request = scsi_mq_init_request,
1874 .exit_request = scsi_mq_exit_request,
1875 .initialize_rq_fn = scsi_initialize_rq,
1876 .cleanup_rq = scsi_cleanup_rq,
1877 .busy = scsi_mq_lld_busy,
1878 .map_queues = scsi_map_queues,
1881 struct request_queue *scsi_mq_alloc_queue(struct scsi_device *sdev)
1883 sdev->request_queue = blk_mq_init_queue(&sdev->host->tag_set);
1884 if (IS_ERR(sdev->request_queue))
1887 sdev->request_queue->queuedata = sdev;
1888 __scsi_init_queue(sdev->host, sdev->request_queue);
1889 blk_queue_flag_set(QUEUE_FLAG_SCSI_PASSTHROUGH, sdev->request_queue);
1890 return sdev->request_queue;
1893 int scsi_mq_setup_tags(struct Scsi_Host *shost)
1895 unsigned int cmd_size, sgl_size;
1897 sgl_size = max_t(unsigned int, sizeof(struct scatterlist),
1898 scsi_mq_inline_sgl_size(shost));
1899 cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size;
1900 if (scsi_host_get_prot(shost))
1901 cmd_size += sizeof(struct scsi_data_buffer) +
1902 sizeof(struct scatterlist) * SCSI_INLINE_PROT_SG_CNT;
1904 memset(&shost->tag_set, 0, sizeof(shost->tag_set));
1905 if (shost->hostt->commit_rqs)
1906 shost->tag_set.ops = &scsi_mq_ops;
1908 shost->tag_set.ops = &scsi_mq_ops_no_commit;
1909 shost->tag_set.nr_hw_queues = shost->nr_hw_queues ? : 1;
1910 shost->tag_set.queue_depth = shost->can_queue;
1911 shost->tag_set.cmd_size = cmd_size;
1912 shost->tag_set.numa_node = NUMA_NO_NODE;
1913 shost->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
1914 shost->tag_set.flags |=
1915 BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
1916 shost->tag_set.driver_data = shost;
1918 return blk_mq_alloc_tag_set(&shost->tag_set);
1921 void scsi_mq_destroy_tags(struct Scsi_Host *shost)
1923 blk_mq_free_tag_set(&shost->tag_set);
1927 * scsi_device_from_queue - return sdev associated with a request_queue
1928 * @q: The request queue to return the sdev from
1930 * Return the sdev associated with a request queue or NULL if the
1931 * request_queue does not reference a SCSI device.
1933 struct scsi_device *scsi_device_from_queue(struct request_queue *q)
1935 struct scsi_device *sdev = NULL;
1937 if (q->mq_ops == &scsi_mq_ops_no_commit ||
1938 q->mq_ops == &scsi_mq_ops)
1939 sdev = q->queuedata;
1940 if (!sdev || !get_device(&sdev->sdev_gendev))
1945 EXPORT_SYMBOL_GPL(scsi_device_from_queue);
1948 * Function: scsi_block_requests()
1950 * Purpose: Utility function used by low-level drivers to prevent further
1951 * commands from being queued to the device.
1953 * Arguments: shost - Host in question
1957 * Lock status: No locks are assumed held.
1959 * Notes: There is no timer nor any other means by which the requests
1960 * get unblocked other than the low-level driver calling
1961 * scsi_unblock_requests().
1963 void scsi_block_requests(struct Scsi_Host *shost)
1965 shost->host_self_blocked = 1;
1967 EXPORT_SYMBOL(scsi_block_requests);
1970 * Function: scsi_unblock_requests()
1972 * Purpose: Utility function used by low-level drivers to allow further
1973 * commands from being queued to the device.
1975 * Arguments: shost - Host in question
1979 * Lock status: No locks are assumed held.
1981 * Notes: There is no timer nor any other means by which the requests
1982 * get unblocked other than the low-level driver calling
1983 * scsi_unblock_requests().
1985 * This is done as an API function so that changes to the
1986 * internals of the scsi mid-layer won't require wholesale
1987 * changes to drivers that use this feature.
1989 void scsi_unblock_requests(struct Scsi_Host *shost)
1991 shost->host_self_blocked = 0;
1992 scsi_run_host_queues(shost);
1994 EXPORT_SYMBOL(scsi_unblock_requests);
1996 int __init scsi_init_queue(void)
1998 scsi_sdb_cache = kmem_cache_create("scsi_data_buffer",
1999 sizeof(struct scsi_data_buffer),
2001 if (!scsi_sdb_cache) {
2002 printk(KERN_ERR "SCSI: can't init scsi sdb cache\n");
2009 void scsi_exit_queue(void)
2011 kmem_cache_destroy(scsi_sense_cache);
2012 kmem_cache_destroy(scsi_sense_isadma_cache);
2013 kmem_cache_destroy(scsi_sdb_cache);
2017 * scsi_mode_select - issue a mode select
2018 * @sdev: SCSI device to be queried
2019 * @pf: Page format bit (1 == standard, 0 == vendor specific)
2020 * @sp: Save page bit (0 == don't save, 1 == save)
2021 * @modepage: mode page being requested
2022 * @buffer: request buffer (may not be smaller than eight bytes)
2023 * @len: length of request buffer.
2024 * @timeout: command timeout
2025 * @retries: number of retries before failing
2026 * @data: returns a structure abstracting the mode header data
2027 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2028 * must be SCSI_SENSE_BUFFERSIZE big.
2030 * Returns zero if successful; negative error number or scsi
2035 scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
2036 unsigned char *buffer, int len, int timeout, int retries,
2037 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2039 unsigned char cmd[10];
2040 unsigned char *real_buffer;
2043 memset(cmd, 0, sizeof(cmd));
2044 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
2046 if (sdev->use_10_for_ms) {
2049 real_buffer = kmalloc(8 + len, GFP_KERNEL);
2052 memcpy(real_buffer + 8, buffer, len);
2056 real_buffer[2] = data->medium_type;
2057 real_buffer[3] = data->device_specific;
2058 real_buffer[4] = data->longlba ? 0x01 : 0;
2060 real_buffer[6] = data->block_descriptor_length >> 8;
2061 real_buffer[7] = data->block_descriptor_length;
2063 cmd[0] = MODE_SELECT_10;
2067 if (len > 255 || data->block_descriptor_length > 255 ||
2071 real_buffer = kmalloc(4 + len, GFP_KERNEL);
2074 memcpy(real_buffer + 4, buffer, len);
2077 real_buffer[1] = data->medium_type;
2078 real_buffer[2] = data->device_specific;
2079 real_buffer[3] = data->block_descriptor_length;
2082 cmd[0] = MODE_SELECT;
2086 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
2087 sshdr, timeout, retries, NULL);
2091 EXPORT_SYMBOL_GPL(scsi_mode_select);
2094 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
2095 * @sdev: SCSI device to be queried
2096 * @dbd: set if mode sense will allow block descriptors to be returned
2097 * @modepage: mode page being requested
2098 * @buffer: request buffer (may not be smaller than eight bytes)
2099 * @len: length of request buffer.
2100 * @timeout: command timeout
2101 * @retries: number of retries before failing
2102 * @data: returns a structure abstracting the mode header data
2103 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2104 * must be SCSI_SENSE_BUFFERSIZE big.
2106 * Returns zero if unsuccessful, or the header offset (either 4
2107 * or 8 depending on whether a six or ten byte command was
2108 * issued) if successful.
2111 scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
2112 unsigned char *buffer, int len, int timeout, int retries,
2113 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2115 unsigned char cmd[12];
2118 int result, retry_count = retries;
2119 struct scsi_sense_hdr my_sshdr;
2121 memset(data, 0, sizeof(*data));
2122 memset(&cmd[0], 0, 12);
2124 dbd = sdev->set_dbd_for_ms ? 8 : dbd;
2125 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
2128 /* caller might not be interested in sense, but we need it */
2133 use_10_for_ms = sdev->use_10_for_ms;
2135 if (use_10_for_ms) {
2139 cmd[0] = MODE_SENSE_10;
2146 cmd[0] = MODE_SENSE;
2151 memset(buffer, 0, len);
2153 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
2154 sshdr, timeout, retries, NULL);
2156 /* This code looks awful: what it's doing is making sure an
2157 * ILLEGAL REQUEST sense return identifies the actual command
2158 * byte as the problem. MODE_SENSE commands can return
2159 * ILLEGAL REQUEST if the code page isn't supported */
2161 if (use_10_for_ms && !scsi_status_is_good(result) &&
2162 driver_byte(result) == DRIVER_SENSE) {
2163 if (scsi_sense_valid(sshdr)) {
2164 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
2165 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
2167 * Invalid command operation code
2169 sdev->use_10_for_ms = 0;
2175 if(scsi_status_is_good(result)) {
2176 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
2177 (modepage == 6 || modepage == 8))) {
2178 /* Initio breakage? */
2181 data->medium_type = 0;
2182 data->device_specific = 0;
2184 data->block_descriptor_length = 0;
2185 } else if(use_10_for_ms) {
2186 data->length = buffer[0]*256 + buffer[1] + 2;
2187 data->medium_type = buffer[2];
2188 data->device_specific = buffer[3];
2189 data->longlba = buffer[4] & 0x01;
2190 data->block_descriptor_length = buffer[6]*256
2193 data->length = buffer[0] + 1;
2194 data->medium_type = buffer[1];
2195 data->device_specific = buffer[2];
2196 data->block_descriptor_length = buffer[3];
2198 data->header_length = header_length;
2199 } else if ((status_byte(result) == CHECK_CONDITION) &&
2200 scsi_sense_valid(sshdr) &&
2201 sshdr->sense_key == UNIT_ATTENTION && retry_count) {
2208 EXPORT_SYMBOL(scsi_mode_sense);
2211 * scsi_test_unit_ready - test if unit is ready
2212 * @sdev: scsi device to change the state of.
2213 * @timeout: command timeout
2214 * @retries: number of retries before failing
2215 * @sshdr: outpout pointer for decoded sense information.
2217 * Returns zero if unsuccessful or an error if TUR failed. For
2218 * removable media, UNIT_ATTENTION sets ->changed flag.
2221 scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2222 struct scsi_sense_hdr *sshdr)
2225 TEST_UNIT_READY, 0, 0, 0, 0, 0,
2229 /* try to eat the UNIT_ATTENTION if there are enough retries */
2231 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
2233 if (sdev->removable && scsi_sense_valid(sshdr) &&
2234 sshdr->sense_key == UNIT_ATTENTION)
2236 } while (scsi_sense_valid(sshdr) &&
2237 sshdr->sense_key == UNIT_ATTENTION && --retries);
2241 EXPORT_SYMBOL(scsi_test_unit_ready);
2244 * scsi_device_set_state - Take the given device through the device state model.
2245 * @sdev: scsi device to change the state of.
2246 * @state: state to change to.
2248 * Returns zero if successful or an error if the requested
2249 * transition is illegal.
2252 scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2254 enum scsi_device_state oldstate = sdev->sdev_state;
2256 if (state == oldstate)
2262 case SDEV_CREATED_BLOCK:
2273 case SDEV_TRANSPORT_OFFLINE:
2286 case SDEV_TRANSPORT_OFFLINE:
2294 case SDEV_TRANSPORT_OFFLINE:
2309 case SDEV_CREATED_BLOCK:
2318 case SDEV_CREATED_BLOCK:
2333 case SDEV_TRANSPORT_OFFLINE:
2345 case SDEV_TRANSPORT_OFFLINE:
2348 case SDEV_CREATED_BLOCK:
2356 sdev->offline_already = false;
2357 sdev->sdev_state = state;
2361 SCSI_LOG_ERROR_RECOVERY(1,
2362 sdev_printk(KERN_ERR, sdev,
2363 "Illegal state transition %s->%s",
2364 scsi_device_state_name(oldstate),
2365 scsi_device_state_name(state))
2369 EXPORT_SYMBOL(scsi_device_set_state);
2372 * sdev_evt_emit - emit a single SCSI device uevent
2373 * @sdev: associated SCSI device
2374 * @evt: event to emit
2376 * Send a single uevent (scsi_event) to the associated scsi_device.
2378 static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2383 switch (evt->evt_type) {
2384 case SDEV_EVT_MEDIA_CHANGE:
2385 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2387 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2388 scsi_rescan_device(&sdev->sdev_gendev);
2389 envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2391 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2392 envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2394 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2395 envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2397 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2398 envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2400 case SDEV_EVT_LUN_CHANGE_REPORTED:
2401 envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2403 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2404 envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
2406 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2407 envp[idx++] = "SDEV_UA=POWER_ON_RESET_OCCURRED";
2416 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2420 * sdev_evt_thread - send a uevent for each scsi event
2421 * @work: work struct for scsi_device
2423 * Dispatch queued events to their associated scsi_device kobjects
2426 void scsi_evt_thread(struct work_struct *work)
2428 struct scsi_device *sdev;
2429 enum scsi_device_event evt_type;
2430 LIST_HEAD(event_list);
2432 sdev = container_of(work, struct scsi_device, event_work);
2434 for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
2435 if (test_and_clear_bit(evt_type, sdev->pending_events))
2436 sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
2439 struct scsi_event *evt;
2440 struct list_head *this, *tmp;
2441 unsigned long flags;
2443 spin_lock_irqsave(&sdev->list_lock, flags);
2444 list_splice_init(&sdev->event_list, &event_list);
2445 spin_unlock_irqrestore(&sdev->list_lock, flags);
2447 if (list_empty(&event_list))
2450 list_for_each_safe(this, tmp, &event_list) {
2451 evt = list_entry(this, struct scsi_event, node);
2452 list_del(&evt->node);
2453 scsi_evt_emit(sdev, evt);
2460 * sdev_evt_send - send asserted event to uevent thread
2461 * @sdev: scsi_device event occurred on
2462 * @evt: event to send
2464 * Assert scsi device event asynchronously.
2466 void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2468 unsigned long flags;
2471 /* FIXME: currently this check eliminates all media change events
2472 * for polled devices. Need to update to discriminate between AN
2473 * and polled events */
2474 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2480 spin_lock_irqsave(&sdev->list_lock, flags);
2481 list_add_tail(&evt->node, &sdev->event_list);
2482 schedule_work(&sdev->event_work);
2483 spin_unlock_irqrestore(&sdev->list_lock, flags);
2485 EXPORT_SYMBOL_GPL(sdev_evt_send);
2488 * sdev_evt_alloc - allocate a new scsi event
2489 * @evt_type: type of event to allocate
2490 * @gfpflags: GFP flags for allocation
2492 * Allocates and returns a new scsi_event.
2494 struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2497 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2501 evt->evt_type = evt_type;
2502 INIT_LIST_HEAD(&evt->node);
2504 /* evt_type-specific initialization, if any */
2506 case SDEV_EVT_MEDIA_CHANGE:
2507 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2508 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2509 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2510 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2511 case SDEV_EVT_LUN_CHANGE_REPORTED:
2512 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2513 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2521 EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2524 * sdev_evt_send_simple - send asserted event to uevent thread
2525 * @sdev: scsi_device event occurred on
2526 * @evt_type: type of event to send
2527 * @gfpflags: GFP flags for allocation
2529 * Assert scsi device event asynchronously, given an event type.
2531 void sdev_evt_send_simple(struct scsi_device *sdev,
2532 enum scsi_device_event evt_type, gfp_t gfpflags)
2534 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2536 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2541 sdev_evt_send(sdev, evt);
2543 EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2546 * scsi_device_quiesce - Block user issued commands.
2547 * @sdev: scsi device to quiesce.
2549 * This works by trying to transition to the SDEV_QUIESCE state
2550 * (which must be a legal transition). When the device is in this
2551 * state, only special requests will be accepted, all others will
2552 * be deferred. Since special requests may also be requeued requests,
2553 * a successful return doesn't guarantee the device will be
2554 * totally quiescent.
2556 * Must be called with user context, may sleep.
2558 * Returns zero if unsuccessful or an error if not.
2561 scsi_device_quiesce(struct scsi_device *sdev)
2563 struct request_queue *q = sdev->request_queue;
2567 * It is allowed to call scsi_device_quiesce() multiple times from
2568 * the same context but concurrent scsi_device_quiesce() calls are
2571 WARN_ON_ONCE(sdev->quiesced_by && sdev->quiesced_by != current);
2573 if (sdev->quiesced_by == current)
2578 blk_mq_freeze_queue(q);
2580 * Ensure that the effect of blk_set_pm_only() will be visible
2581 * for percpu_ref_tryget() callers that occur after the queue
2582 * unfreeze even if the queue was already frozen before this function
2583 * was called. See also https://lwn.net/Articles/573497/.
2586 blk_mq_unfreeze_queue(q);
2588 mutex_lock(&sdev->state_mutex);
2589 err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2591 sdev->quiesced_by = current;
2593 blk_clear_pm_only(q);
2594 mutex_unlock(&sdev->state_mutex);
2598 EXPORT_SYMBOL(scsi_device_quiesce);
2601 * scsi_device_resume - Restart user issued commands to a quiesced device.
2602 * @sdev: scsi device to resume.
2604 * Moves the device from quiesced back to running and restarts the
2607 * Must be called with user context, may sleep.
2609 void scsi_device_resume(struct scsi_device *sdev)
2611 /* check if the device state was mutated prior to resume, and if
2612 * so assume the state is being managed elsewhere (for example
2613 * device deleted during suspend)
2615 mutex_lock(&sdev->state_mutex);
2616 if (sdev->quiesced_by) {
2617 sdev->quiesced_by = NULL;
2618 blk_clear_pm_only(sdev->request_queue);
2620 if (sdev->sdev_state == SDEV_QUIESCE)
2621 scsi_device_set_state(sdev, SDEV_RUNNING);
2622 mutex_unlock(&sdev->state_mutex);
2624 EXPORT_SYMBOL(scsi_device_resume);
2627 device_quiesce_fn(struct scsi_device *sdev, void *data)
2629 scsi_device_quiesce(sdev);
2633 scsi_target_quiesce(struct scsi_target *starget)
2635 starget_for_each_device(starget, NULL, device_quiesce_fn);
2637 EXPORT_SYMBOL(scsi_target_quiesce);
2640 device_resume_fn(struct scsi_device *sdev, void *data)
2642 scsi_device_resume(sdev);
2646 scsi_target_resume(struct scsi_target *starget)
2648 starget_for_each_device(starget, NULL, device_resume_fn);
2650 EXPORT_SYMBOL(scsi_target_resume);
2653 * scsi_internal_device_block_nowait - try to transition to the SDEV_BLOCK state
2654 * @sdev: device to block
2656 * Pause SCSI command processing on the specified device. Does not sleep.
2658 * Returns zero if successful or a negative error code upon failure.
2661 * This routine transitions the device to the SDEV_BLOCK state (which must be
2662 * a legal transition). When the device is in this state, command processing
2663 * is paused until the device leaves the SDEV_BLOCK state. See also
2664 * scsi_internal_device_unblock_nowait().
2666 int scsi_internal_device_block_nowait(struct scsi_device *sdev)
2668 struct request_queue *q = sdev->request_queue;
2671 err = scsi_device_set_state(sdev, SDEV_BLOCK);
2673 err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2680 * The device has transitioned to SDEV_BLOCK. Stop the
2681 * block layer from calling the midlayer with this device's
2684 blk_mq_quiesce_queue_nowait(q);
2687 EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait);
2690 * scsi_internal_device_block - try to transition to the SDEV_BLOCK state
2691 * @sdev: device to block
2693 * Pause SCSI command processing on the specified device and wait until all
2694 * ongoing scsi_request_fn() / scsi_queue_rq() calls have finished. May sleep.
2696 * Returns zero if successful or a negative error code upon failure.
2699 * This routine transitions the device to the SDEV_BLOCK state (which must be
2700 * a legal transition). When the device is in this state, command processing
2701 * is paused until the device leaves the SDEV_BLOCK state. See also
2702 * scsi_internal_device_unblock().
2704 static int scsi_internal_device_block(struct scsi_device *sdev)
2706 struct request_queue *q = sdev->request_queue;
2709 mutex_lock(&sdev->state_mutex);
2710 err = scsi_internal_device_block_nowait(sdev);
2712 blk_mq_quiesce_queue(q);
2713 mutex_unlock(&sdev->state_mutex);
2718 void scsi_start_queue(struct scsi_device *sdev)
2720 struct request_queue *q = sdev->request_queue;
2722 blk_mq_unquiesce_queue(q);
2726 * scsi_internal_device_unblock_nowait - resume a device after a block request
2727 * @sdev: device to resume
2728 * @new_state: state to set the device to after unblocking
2730 * Restart the device queue for a previously suspended SCSI device. Does not
2733 * Returns zero if successful or a negative error code upon failure.
2736 * This routine transitions the device to the SDEV_RUNNING state or to one of
2737 * the offline states (which must be a legal transition) allowing the midlayer
2738 * to goose the queue for this device.
2740 int scsi_internal_device_unblock_nowait(struct scsi_device *sdev,
2741 enum scsi_device_state new_state)
2743 switch (new_state) {
2745 case SDEV_TRANSPORT_OFFLINE:
2752 * Try to transition the scsi device to SDEV_RUNNING or one of the
2753 * offlined states and goose the device queue if successful.
2755 switch (sdev->sdev_state) {
2757 case SDEV_TRANSPORT_OFFLINE:
2758 sdev->sdev_state = new_state;
2760 case SDEV_CREATED_BLOCK:
2761 if (new_state == SDEV_TRANSPORT_OFFLINE ||
2762 new_state == SDEV_OFFLINE)
2763 sdev->sdev_state = new_state;
2765 sdev->sdev_state = SDEV_CREATED;
2773 scsi_start_queue(sdev);
2777 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock_nowait);
2780 * scsi_internal_device_unblock - resume a device after a block request
2781 * @sdev: device to resume
2782 * @new_state: state to set the device to after unblocking
2784 * Restart the device queue for a previously suspended SCSI device. May sleep.
2786 * Returns zero if successful or a negative error code upon failure.
2789 * This routine transitions the device to the SDEV_RUNNING state or to one of
2790 * the offline states (which must be a legal transition) allowing the midlayer
2791 * to goose the queue for this device.
2793 static int scsi_internal_device_unblock(struct scsi_device *sdev,
2794 enum scsi_device_state new_state)
2798 mutex_lock(&sdev->state_mutex);
2799 ret = scsi_internal_device_unblock_nowait(sdev, new_state);
2800 mutex_unlock(&sdev->state_mutex);
2806 device_block(struct scsi_device *sdev, void *data)
2810 ret = scsi_internal_device_block(sdev);
2812 WARN_ONCE(ret, "scsi_internal_device_block(%s) failed: ret = %d\n",
2813 dev_name(&sdev->sdev_gendev), ret);
2817 target_block(struct device *dev, void *data)
2819 if (scsi_is_target_device(dev))
2820 starget_for_each_device(to_scsi_target(dev), NULL,
2826 scsi_target_block(struct device *dev)
2828 if (scsi_is_target_device(dev))
2829 starget_for_each_device(to_scsi_target(dev), NULL,
2832 device_for_each_child(dev, NULL, target_block);
2834 EXPORT_SYMBOL_GPL(scsi_target_block);
2837 device_unblock(struct scsi_device *sdev, void *data)
2839 scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
2843 target_unblock(struct device *dev, void *data)
2845 if (scsi_is_target_device(dev))
2846 starget_for_each_device(to_scsi_target(dev), data,
2852 scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
2854 if (scsi_is_target_device(dev))
2855 starget_for_each_device(to_scsi_target(dev), &new_state,
2858 device_for_each_child(dev, &new_state, target_unblock);
2860 EXPORT_SYMBOL_GPL(scsi_target_unblock);
2863 scsi_host_block(struct Scsi_Host *shost)
2865 struct scsi_device *sdev;
2868 shost_for_each_device(sdev, shost) {
2869 ret = scsi_internal_device_block(sdev);
2875 EXPORT_SYMBOL_GPL(scsi_host_block);
2878 scsi_host_unblock(struct Scsi_Host *shost, int new_state)
2880 struct scsi_device *sdev;
2883 shost_for_each_device(sdev, shost) {
2884 ret = scsi_internal_device_unblock(sdev, new_state);
2890 EXPORT_SYMBOL_GPL(scsi_host_unblock);
2893 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
2894 * @sgl: scatter-gather list
2895 * @sg_count: number of segments in sg
2896 * @offset: offset in bytes into sg, on return offset into the mapped area
2897 * @len: bytes to map, on return number of bytes mapped
2899 * Returns virtual address of the start of the mapped page
2901 void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
2902 size_t *offset, size_t *len)
2905 size_t sg_len = 0, len_complete = 0;
2906 struct scatterlist *sg;
2909 WARN_ON(!irqs_disabled());
2911 for_each_sg(sgl, sg, sg_count, i) {
2912 len_complete = sg_len; /* Complete sg-entries */
2913 sg_len += sg->length;
2914 if (sg_len > *offset)
2918 if (unlikely(i == sg_count)) {
2919 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
2921 __func__, sg_len, *offset, sg_count);
2926 /* Offset starting from the beginning of first page in this sg-entry */
2927 *offset = *offset - len_complete + sg->offset;
2929 /* Assumption: contiguous pages can be accessed as "page + i" */
2930 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
2931 *offset &= ~PAGE_MASK;
2933 /* Bytes in this sg-entry from *offset to the end of the page */
2934 sg_len = PAGE_SIZE - *offset;
2938 return kmap_atomic(page);
2940 EXPORT_SYMBOL(scsi_kmap_atomic_sg);
2943 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
2944 * @virt: virtual address to be unmapped
2946 void scsi_kunmap_atomic_sg(void *virt)
2948 kunmap_atomic(virt);
2950 EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
2952 void sdev_disable_disk_events(struct scsi_device *sdev)
2954 atomic_inc(&sdev->disk_events_disable_depth);
2956 EXPORT_SYMBOL(sdev_disable_disk_events);
2958 void sdev_enable_disk_events(struct scsi_device *sdev)
2960 if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0))
2962 atomic_dec(&sdev->disk_events_disable_depth);
2964 EXPORT_SYMBOL(sdev_enable_disk_events);
2967 * scsi_vpd_lun_id - return a unique device identification
2968 * @sdev: SCSI device
2969 * @id: buffer for the identification
2970 * @id_len: length of the buffer
2972 * Copies a unique device identification into @id based
2973 * on the information in the VPD page 0x83 of the device.
2974 * The string will be formatted as a SCSI name string.
2976 * Returns the length of the identification or error on failure.
2977 * If the identifier is longer than the supplied buffer the actual
2978 * identifier length is returned and the buffer is not zero-padded.
2980 int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len)
2982 u8 cur_id_type = 0xff;
2984 const unsigned char *d, *cur_id_str;
2985 const struct scsi_vpd *vpd_pg83;
2986 int id_size = -EINVAL;
2989 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
2996 * Look for the correct descriptor.
2997 * Order of preference for lun descriptor:
2998 * - SCSI name string
2999 * - NAA IEEE Registered Extended
3000 * - EUI-64 based 16-byte
3001 * - EUI-64 based 12-byte
3002 * - NAA IEEE Registered
3003 * - NAA IEEE Extended
3005 * as longer descriptors reduce the likelyhood
3006 * of identification clashes.
3009 /* The id string must be at least 20 bytes + terminating NULL byte */
3015 memset(id, 0, id_len);
3016 d = vpd_pg83->data + 4;
3017 while (d < vpd_pg83->data + vpd_pg83->len) {
3018 /* Skip designators not referring to the LUN */
3019 if ((d[1] & 0x30) != 0x00)
3022 switch (d[1] & 0xf) {
3025 if (cur_id_size > d[3])
3027 /* Prefer anything */
3028 if (cur_id_type > 0x01 && cur_id_type != 0xff)
3031 if (cur_id_size + 4 > id_len)
3032 cur_id_size = id_len - 4;
3034 cur_id_type = d[1] & 0xf;
3035 id_size = snprintf(id, id_len, "t10.%*pE",
3036 cur_id_size, cur_id_str);
3040 if (cur_id_size > d[3])
3042 /* Prefer NAA IEEE Registered Extended */
3043 if (cur_id_type == 0x3 &&
3044 cur_id_size == d[3])
3048 cur_id_type = d[1] & 0xf;
3049 switch (cur_id_size) {
3051 id_size = snprintf(id, id_len,
3056 id_size = snprintf(id, id_len,
3061 id_size = snprintf(id, id_len,
3072 if (cur_id_size > d[3])
3076 cur_id_type = d[1] & 0xf;
3077 switch (cur_id_size) {
3079 id_size = snprintf(id, id_len,
3084 id_size = snprintf(id, id_len,
3094 /* SCSI name string */
3095 if (cur_id_size + 4 > d[3])
3097 /* Prefer others for truncated descriptor */
3098 if (cur_id_size && d[3] > id_len)
3100 cur_id_size = id_size = d[3];
3102 cur_id_type = d[1] & 0xf;
3103 if (cur_id_size >= id_len)
3104 cur_id_size = id_len - 1;
3105 memcpy(id, cur_id_str, cur_id_size);
3106 /* Decrease priority for truncated descriptor */
3107 if (cur_id_size != id_size)
3120 EXPORT_SYMBOL(scsi_vpd_lun_id);
3123 * scsi_vpd_tpg_id - return a target port group identifier
3124 * @sdev: SCSI device
3126 * Returns the Target Port Group identifier from the information
3127 * froom VPD page 0x83 of the device.
3129 * Returns the identifier or error on failure.
3131 int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id)
3133 const unsigned char *d;
3134 const struct scsi_vpd *vpd_pg83;
3135 int group_id = -EAGAIN, rel_port = -1;
3138 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3144 d = vpd_pg83->data + 4;
3145 while (d < vpd_pg83->data + vpd_pg83->len) {
3146 switch (d[1] & 0xf) {
3148 /* Relative target port */
3149 rel_port = get_unaligned_be16(&d[6]);
3152 /* Target port group */
3153 group_id = get_unaligned_be16(&d[6]);
3162 if (group_id >= 0 && rel_id && rel_port != -1)
3167 EXPORT_SYMBOL(scsi_vpd_tpg_id);