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_sense_cache;
56 static DEFINE_MUTEX(scsi_sense_cache_mutex);
58 static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd);
60 int scsi_init_sense_cache(struct Scsi_Host *shost)
64 mutex_lock(&scsi_sense_cache_mutex);
65 if (!scsi_sense_cache) {
67 kmem_cache_create_usercopy("scsi_sense_cache",
68 SCSI_SENSE_BUFFERSIZE, 0, SLAB_HWCACHE_ALIGN,
69 0, SCSI_SENSE_BUFFERSIZE, NULL);
70 if (!scsi_sense_cache)
73 mutex_unlock(&scsi_sense_cache_mutex);
78 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
79 * not change behaviour from the previous unplug mechanism, experimentation
80 * may prove this needs changing.
82 #define SCSI_QUEUE_DELAY 3
85 scsi_set_blocked(struct scsi_cmnd *cmd, int reason)
87 struct Scsi_Host *host = cmd->device->host;
88 struct scsi_device *device = cmd->device;
89 struct scsi_target *starget = scsi_target(device);
92 * Set the appropriate busy bit for the device/host.
94 * If the host/device isn't busy, assume that something actually
95 * completed, and that we should be able to queue a command now.
97 * Note that the prior mid-layer assumption that any host could
98 * always queue at least one command is now broken. The mid-layer
99 * will implement a user specifiable stall (see
100 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
101 * if a command is requeued with no other commands outstanding
102 * either for the device or for the host.
105 case SCSI_MLQUEUE_HOST_BUSY:
106 atomic_set(&host->host_blocked, host->max_host_blocked);
108 case SCSI_MLQUEUE_DEVICE_BUSY:
109 case SCSI_MLQUEUE_EH_RETRY:
110 atomic_set(&device->device_blocked,
111 device->max_device_blocked);
113 case SCSI_MLQUEUE_TARGET_BUSY:
114 atomic_set(&starget->target_blocked,
115 starget->max_target_blocked);
120 static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd)
122 if (cmd->request->rq_flags & RQF_DONTPREP) {
123 cmd->request->rq_flags &= ~RQF_DONTPREP;
124 scsi_mq_uninit_cmd(cmd);
128 blk_mq_requeue_request(cmd->request, true);
132 * __scsi_queue_insert - private queue insertion
133 * @cmd: The SCSI command being requeued
134 * @reason: The reason for the requeue
135 * @unbusy: Whether the queue should be unbusied
137 * This is a private queue insertion. The public interface
138 * scsi_queue_insert() always assumes the queue should be unbusied
139 * because it's always called before the completion. This function is
140 * for a requeue after completion, which should only occur in this
143 static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy)
145 struct scsi_device *device = cmd->device;
147 SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd,
148 "Inserting command %p into mlqueue\n", cmd));
150 scsi_set_blocked(cmd, reason);
153 * Decrement the counters, since these commands are no longer
154 * active on the host/device.
157 scsi_device_unbusy(device, cmd);
160 * Requeue this command. It will go before all other commands
161 * that are already in the queue. Schedule requeue work under
162 * lock such that the kblockd_schedule_work() call happens
163 * before blk_cleanup_queue() finishes.
167 blk_mq_requeue_request(cmd->request, true);
171 * scsi_queue_insert - Reinsert a command in the queue.
172 * @cmd: command that we are adding to queue.
173 * @reason: why we are inserting command to queue.
175 * We do this for one of two cases. Either the host is busy and it cannot accept
176 * any more commands for the time being, or the device returned QUEUE_FULL and
177 * can accept no more commands.
179 * Context: This could be called either from an interrupt context or a normal
182 void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
184 __scsi_queue_insert(cmd, reason, true);
189 * __scsi_execute - insert request and wait for the result
192 * @data_direction: data direction
193 * @buffer: data buffer
194 * @bufflen: len of buffer
195 * @sense: optional sense buffer
196 * @sshdr: optional decoded sense header
197 * @timeout: request timeout in HZ
198 * @retries: number of times to retry request
199 * @flags: flags for ->cmd_flags
200 * @rq_flags: flags for ->rq_flags
201 * @resid: optional residual length
203 * Returns the scsi_cmnd result field if a command was executed, or a negative
204 * Linux error code if we didn't get that far.
206 int __scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
207 int data_direction, void *buffer, unsigned bufflen,
208 unsigned char *sense, struct scsi_sense_hdr *sshdr,
209 int timeout, int retries, u64 flags, req_flags_t rq_flags,
213 struct scsi_request *rq;
216 req = blk_get_request(sdev->request_queue,
217 data_direction == DMA_TO_DEVICE ?
218 REQ_OP_DRV_OUT : REQ_OP_DRV_IN,
219 rq_flags & RQF_PM ? BLK_MQ_REQ_PM : 0);
226 ret = blk_rq_map_kern(sdev->request_queue, req,
227 buffer, bufflen, GFP_NOIO);
231 rq->cmd_len = COMMAND_SIZE(cmd[0]);
232 memcpy(rq->cmd, cmd, rq->cmd_len);
233 rq->retries = retries;
234 req->timeout = timeout;
235 req->cmd_flags |= flags;
236 req->rq_flags |= rq_flags | RQF_QUIET;
239 * head injection *required* here otherwise quiesce won't work
241 blk_execute_rq(NULL, req, 1);
244 * Some devices (USB mass-storage in particular) may transfer
245 * garbage data together with a residue indicating that the data
246 * is invalid. Prevent the garbage from being misinterpreted
247 * and prevent security leaks by zeroing out the excess data.
249 if (unlikely(rq->resid_len > 0 && rq->resid_len <= bufflen))
250 memset(buffer + (bufflen - rq->resid_len), 0, rq->resid_len);
253 *resid = rq->resid_len;
254 if (sense && rq->sense_len)
255 memcpy(sense, rq->sense, SCSI_SENSE_BUFFERSIZE);
257 scsi_normalize_sense(rq->sense, rq->sense_len, sshdr);
260 blk_put_request(req);
264 EXPORT_SYMBOL(__scsi_execute);
267 * Wake up the error handler if necessary. Avoid as follows that the error
268 * handler is not woken up if host in-flight requests number ==
269 * shost->host_failed: use call_rcu() in scsi_eh_scmd_add() in combination
270 * with an RCU read lock in this function to ensure that this function in
271 * its entirety either finishes before scsi_eh_scmd_add() increases the
272 * host_failed counter or that it notices the shost state change made by
273 * scsi_eh_scmd_add().
275 static void scsi_dec_host_busy(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
280 __clear_bit(SCMD_STATE_INFLIGHT, &cmd->state);
281 if (unlikely(scsi_host_in_recovery(shost))) {
282 spin_lock_irqsave(shost->host_lock, flags);
283 if (shost->host_failed || shost->host_eh_scheduled)
284 scsi_eh_wakeup(shost);
285 spin_unlock_irqrestore(shost->host_lock, flags);
290 void scsi_device_unbusy(struct scsi_device *sdev, struct scsi_cmnd *cmd)
292 struct Scsi_Host *shost = sdev->host;
293 struct scsi_target *starget = scsi_target(sdev);
295 scsi_dec_host_busy(shost, cmd);
297 if (starget->can_queue > 0)
298 atomic_dec(&starget->target_busy);
300 sbitmap_put(&sdev->budget_map, cmd->budget_token);
301 cmd->budget_token = -1;
304 static void scsi_kick_queue(struct request_queue *q)
306 blk_mq_run_hw_queues(q, false);
310 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
311 * and call blk_run_queue for all the scsi_devices on the target -
312 * including current_sdev first.
314 * Called with *no* scsi locks held.
316 static void scsi_single_lun_run(struct scsi_device *current_sdev)
318 struct Scsi_Host *shost = current_sdev->host;
319 struct scsi_device *sdev, *tmp;
320 struct scsi_target *starget = scsi_target(current_sdev);
323 spin_lock_irqsave(shost->host_lock, flags);
324 starget->starget_sdev_user = NULL;
325 spin_unlock_irqrestore(shost->host_lock, flags);
328 * Call blk_run_queue for all LUNs on the target, starting with
329 * current_sdev. We race with others (to set starget_sdev_user),
330 * but in most cases, we will be first. Ideally, each LU on the
331 * target would get some limited time or requests on the target.
333 scsi_kick_queue(current_sdev->request_queue);
335 spin_lock_irqsave(shost->host_lock, flags);
336 if (starget->starget_sdev_user)
338 list_for_each_entry_safe(sdev, tmp, &starget->devices,
339 same_target_siblings) {
340 if (sdev == current_sdev)
342 if (scsi_device_get(sdev))
345 spin_unlock_irqrestore(shost->host_lock, flags);
346 scsi_kick_queue(sdev->request_queue);
347 spin_lock_irqsave(shost->host_lock, flags);
349 scsi_device_put(sdev);
352 spin_unlock_irqrestore(shost->host_lock, flags);
355 static inline bool scsi_device_is_busy(struct scsi_device *sdev)
357 if (scsi_device_busy(sdev) >= sdev->queue_depth)
359 if (atomic_read(&sdev->device_blocked) > 0)
364 static inline bool scsi_target_is_busy(struct scsi_target *starget)
366 if (starget->can_queue > 0) {
367 if (atomic_read(&starget->target_busy) >= starget->can_queue)
369 if (atomic_read(&starget->target_blocked) > 0)
375 static inline bool scsi_host_is_busy(struct Scsi_Host *shost)
377 if (atomic_read(&shost->host_blocked) > 0)
379 if (shost->host_self_blocked)
384 static void scsi_starved_list_run(struct Scsi_Host *shost)
386 LIST_HEAD(starved_list);
387 struct scsi_device *sdev;
390 spin_lock_irqsave(shost->host_lock, flags);
391 list_splice_init(&shost->starved_list, &starved_list);
393 while (!list_empty(&starved_list)) {
394 struct request_queue *slq;
397 * As long as shost is accepting commands and we have
398 * starved queues, call blk_run_queue. scsi_request_fn
399 * drops the queue_lock and can add us back to the
402 * host_lock protects the starved_list and starved_entry.
403 * scsi_request_fn must get the host_lock before checking
404 * or modifying starved_list or starved_entry.
406 if (scsi_host_is_busy(shost))
409 sdev = list_entry(starved_list.next,
410 struct scsi_device, starved_entry);
411 list_del_init(&sdev->starved_entry);
412 if (scsi_target_is_busy(scsi_target(sdev))) {
413 list_move_tail(&sdev->starved_entry,
414 &shost->starved_list);
419 * Once we drop the host lock, a racing scsi_remove_device()
420 * call may remove the sdev from the starved list and destroy
421 * it and the queue. Mitigate by taking a reference to the
422 * queue and never touching the sdev again after we drop the
423 * host lock. Note: if __scsi_remove_device() invokes
424 * blk_cleanup_queue() before the queue is run from this
425 * function then blk_run_queue() will return immediately since
426 * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING.
428 slq = sdev->request_queue;
429 if (!blk_get_queue(slq))
431 spin_unlock_irqrestore(shost->host_lock, flags);
433 scsi_kick_queue(slq);
436 spin_lock_irqsave(shost->host_lock, flags);
438 /* put any unprocessed entries back */
439 list_splice(&starved_list, &shost->starved_list);
440 spin_unlock_irqrestore(shost->host_lock, flags);
444 * scsi_run_queue - Select a proper request queue to serve next.
445 * @q: last request's queue
447 * The previous command was completely finished, start a new one if possible.
449 static void scsi_run_queue(struct request_queue *q)
451 struct scsi_device *sdev = q->queuedata;
453 if (scsi_target(sdev)->single_lun)
454 scsi_single_lun_run(sdev);
455 if (!list_empty(&sdev->host->starved_list))
456 scsi_starved_list_run(sdev->host);
458 blk_mq_run_hw_queues(q, false);
461 void scsi_requeue_run_queue(struct work_struct *work)
463 struct scsi_device *sdev;
464 struct request_queue *q;
466 sdev = container_of(work, struct scsi_device, requeue_work);
467 q = sdev->request_queue;
471 void scsi_run_host_queues(struct Scsi_Host *shost)
473 struct scsi_device *sdev;
475 shost_for_each_device(sdev, shost)
476 scsi_run_queue(sdev->request_queue);
479 static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
481 if (!blk_rq_is_passthrough(cmd->request)) {
482 struct scsi_driver *drv = scsi_cmd_to_driver(cmd);
484 if (drv->uninit_command)
485 drv->uninit_command(cmd);
489 void scsi_free_sgtables(struct scsi_cmnd *cmd)
491 if (cmd->sdb.table.nents)
492 sg_free_table_chained(&cmd->sdb.table,
494 if (scsi_prot_sg_count(cmd))
495 sg_free_table_chained(&cmd->prot_sdb->table,
496 SCSI_INLINE_PROT_SG_CNT);
498 EXPORT_SYMBOL_GPL(scsi_free_sgtables);
500 static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
502 scsi_free_sgtables(cmd);
503 scsi_uninit_cmd(cmd);
506 static void scsi_run_queue_async(struct scsi_device *sdev)
508 if (scsi_target(sdev)->single_lun ||
509 !list_empty(&sdev->host->starved_list)) {
510 kblockd_schedule_work(&sdev->requeue_work);
513 * smp_mb() present in sbitmap_queue_clear() or implied in
514 * .end_io is for ordering writing .device_busy in
515 * scsi_device_unbusy() and reading sdev->restarts.
517 int old = atomic_read(&sdev->restarts);
520 * ->restarts has to be kept as non-zero if new budget
523 * No need to run queue when either another re-run
524 * queue wins in updating ->restarts or a new budget
527 if (old && atomic_cmpxchg(&sdev->restarts, old, 0) == old)
528 blk_mq_run_hw_queues(sdev->request_queue, true);
532 /* Returns false when no more bytes to process, true if there are more */
533 static bool scsi_end_request(struct request *req, blk_status_t error,
536 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
537 struct scsi_device *sdev = cmd->device;
538 struct request_queue *q = sdev->request_queue;
540 if (blk_update_request(req, error, bytes))
543 if (blk_queue_add_random(q))
544 add_disk_randomness(req->rq_disk);
546 if (!blk_rq_is_passthrough(req)) {
547 WARN_ON_ONCE(!(cmd->flags & SCMD_INITIALIZED));
548 cmd->flags &= ~SCMD_INITIALIZED;
552 * Calling rcu_barrier() is not necessary here because the
553 * SCSI error handler guarantees that the function called by
554 * call_rcu() has been called before scsi_end_request() is
557 destroy_rcu_head(&cmd->rcu);
560 * In the MQ case the command gets freed by __blk_mq_end_request,
561 * so we have to do all cleanup that depends on it earlier.
563 * We also can't kick the queues from irq context, so we
564 * will have to defer it to a workqueue.
566 scsi_mq_uninit_cmd(cmd);
569 * queue is still alive, so grab the ref for preventing it
570 * from being cleaned up during running queue.
572 percpu_ref_get(&q->q_usage_counter);
574 __blk_mq_end_request(req, error);
576 scsi_run_queue_async(sdev);
578 percpu_ref_put(&q->q_usage_counter);
583 * scsi_result_to_blk_status - translate a SCSI result code into blk_status_t
585 * @result: scsi error code
587 * Translate a SCSI result code into a blk_status_t value. May reset the host
588 * byte of @cmd->result.
590 static blk_status_t scsi_result_to_blk_status(struct scsi_cmnd *cmd, int result)
592 switch (host_byte(result)) {
594 if (scsi_status_is_good(result))
596 return BLK_STS_IOERR;
597 case DID_TRANSPORT_FAILFAST:
598 case DID_TRANSPORT_MARGINAL:
599 return BLK_STS_TRANSPORT;
600 case DID_TARGET_FAILURE:
601 set_host_byte(cmd, DID_OK);
602 return BLK_STS_TARGET;
603 case DID_NEXUS_FAILURE:
604 set_host_byte(cmd, DID_OK);
605 return BLK_STS_NEXUS;
606 case DID_ALLOC_FAILURE:
607 set_host_byte(cmd, DID_OK);
608 return BLK_STS_NOSPC;
609 case DID_MEDIUM_ERROR:
610 set_host_byte(cmd, DID_OK);
611 return BLK_STS_MEDIUM;
613 return BLK_STS_IOERR;
617 /* Helper for scsi_io_completion() when "reprep" action required. */
618 static void scsi_io_completion_reprep(struct scsi_cmnd *cmd,
619 struct request_queue *q)
621 /* A new command will be prepared and issued. */
622 scsi_mq_requeue_cmd(cmd);
625 static bool scsi_cmd_runtime_exceeced(struct scsi_cmnd *cmd)
627 struct request *req = cmd->request;
628 unsigned long wait_for;
630 if (cmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT)
633 wait_for = (cmd->allowed + 1) * req->timeout;
634 if (time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
635 scmd_printk(KERN_ERR, cmd, "timing out command, waited %lus\n",
642 /* Helper for scsi_io_completion() when special action required. */
643 static void scsi_io_completion_action(struct scsi_cmnd *cmd, int result)
645 struct request_queue *q = cmd->device->request_queue;
646 struct request *req = cmd->request;
648 enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,
649 ACTION_DELAYED_RETRY} action;
650 struct scsi_sense_hdr sshdr;
652 bool sense_current = true; /* false implies "deferred sense" */
653 blk_status_t blk_stat;
655 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
657 sense_current = !scsi_sense_is_deferred(&sshdr);
659 blk_stat = scsi_result_to_blk_status(cmd, result);
661 if (host_byte(result) == DID_RESET) {
662 /* Third party bus reset or reset for error recovery
663 * reasons. Just retry the command and see what
666 action = ACTION_RETRY;
667 } else if (sense_valid && sense_current) {
668 switch (sshdr.sense_key) {
670 if (cmd->device->removable) {
671 /* Detected disc change. Set a bit
672 * and quietly refuse further access.
674 cmd->device->changed = 1;
675 action = ACTION_FAIL;
677 /* Must have been a power glitch, or a
678 * bus reset. Could not have been a
679 * media change, so we just retry the
680 * command and see what happens.
682 action = ACTION_RETRY;
685 case ILLEGAL_REQUEST:
686 /* If we had an ILLEGAL REQUEST returned, then
687 * we may have performed an unsupported
688 * command. The only thing this should be
689 * would be a ten byte read where only a six
690 * byte read was supported. Also, on a system
691 * where READ CAPACITY failed, we may have
692 * read past the end of the disk.
694 if ((cmd->device->use_10_for_rw &&
695 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
696 (cmd->cmnd[0] == READ_10 ||
697 cmd->cmnd[0] == WRITE_10)) {
698 /* This will issue a new 6-byte command. */
699 cmd->device->use_10_for_rw = 0;
700 action = ACTION_REPREP;
701 } else if (sshdr.asc == 0x10) /* DIX */ {
702 action = ACTION_FAIL;
703 blk_stat = BLK_STS_PROTECTION;
704 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
705 } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
706 action = ACTION_FAIL;
707 blk_stat = BLK_STS_TARGET;
709 action = ACTION_FAIL;
711 case ABORTED_COMMAND:
712 action = ACTION_FAIL;
713 if (sshdr.asc == 0x10) /* DIF */
714 blk_stat = BLK_STS_PROTECTION;
717 /* If the device is in the process of becoming
718 * ready, or has a temporary blockage, retry.
720 if (sshdr.asc == 0x04) {
721 switch (sshdr.ascq) {
722 case 0x01: /* becoming ready */
723 case 0x04: /* format in progress */
724 case 0x05: /* rebuild in progress */
725 case 0x06: /* recalculation in progress */
726 case 0x07: /* operation in progress */
727 case 0x08: /* Long write in progress */
728 case 0x09: /* self test in progress */
729 case 0x11: /* notify (enable spinup) required */
730 case 0x14: /* space allocation in progress */
731 case 0x1a: /* start stop unit in progress */
732 case 0x1b: /* sanitize in progress */
733 case 0x1d: /* configuration in progress */
734 case 0x24: /* depopulation in progress */
735 action = ACTION_DELAYED_RETRY;
737 case 0x0a: /* ALUA state transition */
738 blk_stat = BLK_STS_AGAIN;
741 action = ACTION_FAIL;
745 action = ACTION_FAIL;
747 case VOLUME_OVERFLOW:
748 /* See SSC3rXX or current. */
749 action = ACTION_FAIL;
752 action = ACTION_FAIL;
753 if ((sshdr.asc == 0x0C && sshdr.ascq == 0x12) ||
754 (sshdr.asc == 0x55 &&
755 (sshdr.ascq == 0x0E || sshdr.ascq == 0x0F))) {
756 /* Insufficient zone resources */
757 blk_stat = BLK_STS_ZONE_OPEN_RESOURCE;
761 action = ACTION_FAIL;
765 action = ACTION_FAIL;
767 if (action != ACTION_FAIL && scsi_cmd_runtime_exceeced(cmd))
768 action = ACTION_FAIL;
772 /* Give up and fail the remainder of the request */
773 if (!(req->rq_flags & RQF_QUIET)) {
774 static DEFINE_RATELIMIT_STATE(_rs,
775 DEFAULT_RATELIMIT_INTERVAL,
776 DEFAULT_RATELIMIT_BURST);
778 if (unlikely(scsi_logging_level))
780 SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
781 SCSI_LOG_MLCOMPLETE_BITS);
784 * if logging is enabled the failure will be printed
785 * in scsi_log_completion(), so avoid duplicate messages
787 if (!level && __ratelimit(&_rs)) {
788 scsi_print_result(cmd, NULL, FAILED);
790 scsi_print_sense(cmd);
791 scsi_print_command(cmd);
794 if (!scsi_end_request(req, blk_stat, blk_rq_err_bytes(req)))
798 scsi_io_completion_reprep(cmd, q);
801 /* Retry the same command immediately */
802 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, false);
804 case ACTION_DELAYED_RETRY:
805 /* Retry the same command after a delay */
806 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, false);
812 * Helper for scsi_io_completion() when cmd->result is non-zero. Returns a
813 * new result that may suppress further error checking. Also modifies
814 * *blk_statp in some cases.
816 static int scsi_io_completion_nz_result(struct scsi_cmnd *cmd, int result,
817 blk_status_t *blk_statp)
820 bool sense_current = true; /* false implies "deferred sense" */
821 struct request *req = cmd->request;
822 struct scsi_sense_hdr sshdr;
824 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
826 sense_current = !scsi_sense_is_deferred(&sshdr);
828 if (blk_rq_is_passthrough(req)) {
831 * SG_IO wants current and deferred errors
833 scsi_req(req)->sense_len =
834 min(8 + cmd->sense_buffer[7],
835 SCSI_SENSE_BUFFERSIZE);
838 *blk_statp = scsi_result_to_blk_status(cmd, result);
839 } else if (blk_rq_bytes(req) == 0 && sense_current) {
841 * Flush commands do not transfers any data, and thus cannot use
842 * good_bytes != blk_rq_bytes(req) as the signal for an error.
843 * This sets *blk_statp explicitly for the problem case.
845 *blk_statp = scsi_result_to_blk_status(cmd, result);
848 * Recovered errors need reporting, but they're always treated as
849 * success, so fiddle the result code here. For passthrough requests
850 * we already took a copy of the original into sreq->result which
851 * is what gets returned to the user
853 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
854 bool do_print = true;
856 * if ATA PASS-THROUGH INFORMATION AVAILABLE [0x0, 0x1d]
857 * skip print since caller wants ATA registers. Only occurs
858 * on SCSI ATA PASS_THROUGH commands when CK_COND=1
860 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
862 else if (req->rq_flags & RQF_QUIET)
865 scsi_print_sense(cmd);
867 /* for passthrough, *blk_statp may be set */
868 *blk_statp = BLK_STS_OK;
871 * Another corner case: the SCSI status byte is non-zero but 'good'.
872 * Example: PRE-FETCH command returns SAM_STAT_CONDITION_MET when
873 * it is able to fit nominated LBs in its cache (and SAM_STAT_GOOD
874 * if it can't fit). Treat SAM_STAT_CONDITION_MET and the related
875 * intermediate statuses (both obsolete in SAM-4) as good.
877 if ((result & 0xff) && scsi_status_is_good(result)) {
879 *blk_statp = BLK_STS_OK;
885 * scsi_io_completion - Completion processing for SCSI commands.
886 * @cmd: command that is finished.
887 * @good_bytes: number of processed bytes.
889 * We will finish off the specified number of sectors. If we are done, the
890 * command block will be released and the queue function will be goosed. If we
891 * are not done then we have to figure out what to do next:
893 * a) We can call scsi_io_completion_reprep(). The request will be
894 * unprepared and put back on the queue. Then a new command will
895 * be created for it. This should be used if we made forward
896 * progress, or if we want to switch from READ(10) to READ(6) for
899 * b) We can call scsi_io_completion_action(). The request will be
900 * put back on the queue and retried using the same command as
901 * before, possibly after a delay.
903 * c) We can call scsi_end_request() with blk_stat other than
904 * BLK_STS_OK, to fail the remainder of the request.
906 void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
908 int result = cmd->result;
909 struct request_queue *q = cmd->device->request_queue;
910 struct request *req = cmd->request;
911 blk_status_t blk_stat = BLK_STS_OK;
913 if (unlikely(result)) /* a nz result may or may not be an error */
914 result = scsi_io_completion_nz_result(cmd, result, &blk_stat);
916 if (unlikely(blk_rq_is_passthrough(req))) {
918 * scsi_result_to_blk_status may have reset the host_byte
920 scsi_req(req)->result = cmd->result;
924 * Next deal with any sectors which we were able to correctly
927 SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd,
928 "%u sectors total, %d bytes done.\n",
929 blk_rq_sectors(req), good_bytes));
932 * Failed, zero length commands always need to drop down
933 * to retry code. Fast path should return in this block.
935 if (likely(blk_rq_bytes(req) > 0 || blk_stat == BLK_STS_OK)) {
936 if (likely(!scsi_end_request(req, blk_stat, good_bytes)))
937 return; /* no bytes remaining */
940 /* Kill remainder if no retries. */
941 if (unlikely(blk_stat && scsi_noretry_cmd(cmd))) {
942 if (scsi_end_request(req, blk_stat, blk_rq_bytes(req)))
944 "Bytes remaining after failed, no-retry command");
949 * If there had been no error, but we have leftover bytes in the
950 * requeues just queue the command up again.
952 if (likely(result == 0))
953 scsi_io_completion_reprep(cmd, q);
955 scsi_io_completion_action(cmd, result);
958 static inline bool scsi_cmd_needs_dma_drain(struct scsi_device *sdev,
961 return sdev->dma_drain_len && blk_rq_is_passthrough(rq) &&
962 !op_is_write(req_op(rq)) &&
963 sdev->host->hostt->dma_need_drain(rq);
967 * scsi_alloc_sgtables - Allocate and initialize data and integrity scatterlists
968 * @cmd: SCSI command data structure to initialize.
970 * Initializes @cmd->sdb and also @cmd->prot_sdb if data integrity is enabled
974 * * BLK_STS_OK - on success
975 * * BLK_STS_RESOURCE - if the failure is retryable
976 * * BLK_STS_IOERR - if the failure is fatal
978 blk_status_t scsi_alloc_sgtables(struct scsi_cmnd *cmd)
980 struct scsi_device *sdev = cmd->device;
981 struct request *rq = cmd->request;
982 unsigned short nr_segs = blk_rq_nr_phys_segments(rq);
983 struct scatterlist *last_sg = NULL;
985 bool need_drain = scsi_cmd_needs_dma_drain(sdev, rq);
988 if (WARN_ON_ONCE(!nr_segs))
989 return BLK_STS_IOERR;
992 * Make sure there is space for the drain. The driver must adjust
993 * max_hw_segments to be prepared for this.
999 * If sg table allocation fails, requeue request later.
1001 if (unlikely(sg_alloc_table_chained(&cmd->sdb.table, nr_segs,
1002 cmd->sdb.table.sgl, SCSI_INLINE_SG_CNT)))
1003 return BLK_STS_RESOURCE;
1006 * Next, walk the list, and fill in the addresses and sizes of
1009 count = __blk_rq_map_sg(rq->q, rq, cmd->sdb.table.sgl, &last_sg);
1011 if (blk_rq_bytes(rq) & rq->q->dma_pad_mask) {
1012 unsigned int pad_len =
1013 (rq->q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1;
1015 last_sg->length += pad_len;
1016 cmd->extra_len += pad_len;
1020 sg_unmark_end(last_sg);
1021 last_sg = sg_next(last_sg);
1022 sg_set_buf(last_sg, sdev->dma_drain_buf, sdev->dma_drain_len);
1023 sg_mark_end(last_sg);
1025 cmd->extra_len += sdev->dma_drain_len;
1029 BUG_ON(count > cmd->sdb.table.nents);
1030 cmd->sdb.table.nents = count;
1031 cmd->sdb.length = blk_rq_payload_bytes(rq);
1033 if (blk_integrity_rq(rq)) {
1034 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1037 if (WARN_ON_ONCE(!prot_sdb)) {
1039 * This can happen if someone (e.g. multipath)
1040 * queues a command to a device on an adapter
1041 * that does not support DIX.
1043 ret = BLK_STS_IOERR;
1044 goto out_free_sgtables;
1047 ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
1049 if (sg_alloc_table_chained(&prot_sdb->table, ivecs,
1050 prot_sdb->table.sgl,
1051 SCSI_INLINE_PROT_SG_CNT)) {
1052 ret = BLK_STS_RESOURCE;
1053 goto out_free_sgtables;
1056 count = blk_rq_map_integrity_sg(rq->q, rq->bio,
1057 prot_sdb->table.sgl);
1058 BUG_ON(count > ivecs);
1059 BUG_ON(count > queue_max_integrity_segments(rq->q));
1061 cmd->prot_sdb = prot_sdb;
1062 cmd->prot_sdb->table.nents = count;
1067 scsi_free_sgtables(cmd);
1070 EXPORT_SYMBOL(scsi_alloc_sgtables);
1073 * scsi_initialize_rq - initialize struct scsi_cmnd partially
1074 * @rq: Request associated with the SCSI command to be initialized.
1076 * This function initializes the members of struct scsi_cmnd that must be
1077 * initialized before request processing starts and that won't be
1078 * reinitialized if a SCSI command is requeued.
1080 * Called from inside blk_get_request() for pass-through requests and from
1081 * inside scsi_init_command() for filesystem requests.
1083 static void scsi_initialize_rq(struct request *rq)
1085 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1087 scsi_req_init(&cmd->req);
1088 init_rcu_head(&cmd->rcu);
1089 cmd->jiffies_at_alloc = jiffies;
1094 * Only called when the request isn't completed by SCSI, and not freed by
1097 static void scsi_cleanup_rq(struct request *rq)
1099 if (rq->rq_flags & RQF_DONTPREP) {
1100 scsi_mq_uninit_cmd(blk_mq_rq_to_pdu(rq));
1101 rq->rq_flags &= ~RQF_DONTPREP;
1105 /* Called before a request is prepared. See also scsi_mq_prep_fn(). */
1106 void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd)
1108 void *buf = cmd->sense_buffer;
1109 void *prot = cmd->prot_sdb;
1110 struct request *rq = blk_mq_rq_from_pdu(cmd);
1111 unsigned int flags = cmd->flags & SCMD_PRESERVED_FLAGS;
1112 unsigned long jiffies_at_alloc;
1113 int retries, to_clear;
1115 int budget_token = cmd->budget_token;
1117 if (!blk_rq_is_passthrough(rq) && !(flags & SCMD_INITIALIZED)) {
1118 flags |= SCMD_INITIALIZED;
1119 scsi_initialize_rq(rq);
1122 jiffies_at_alloc = cmd->jiffies_at_alloc;
1123 retries = cmd->retries;
1124 in_flight = test_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1126 * Zero out the cmd, except for the embedded scsi_request. Only clear
1127 * the driver-private command data if the LLD does not supply a
1128 * function to initialize that data.
1130 to_clear = sizeof(*cmd) - sizeof(cmd->req);
1131 if (!dev->host->hostt->init_cmd_priv)
1132 to_clear += dev->host->hostt->cmd_size;
1133 memset((char *)cmd + sizeof(cmd->req), 0, to_clear);
1136 cmd->sense_buffer = buf;
1137 cmd->prot_sdb = prot;
1139 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
1140 cmd->jiffies_at_alloc = jiffies_at_alloc;
1141 cmd->retries = retries;
1143 __set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1144 cmd->budget_token = budget_token;
1148 static blk_status_t scsi_setup_scsi_cmnd(struct scsi_device *sdev,
1149 struct request *req)
1151 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1154 * Passthrough requests may transfer data, in which case they must
1155 * a bio attached to them. Or they might contain a SCSI command
1156 * that does not transfer data, in which case they may optionally
1157 * submit a request without an attached bio.
1160 blk_status_t ret = scsi_alloc_sgtables(cmd);
1161 if (unlikely(ret != BLK_STS_OK))
1164 BUG_ON(blk_rq_bytes(req));
1166 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1169 cmd->cmd_len = scsi_req(req)->cmd_len;
1170 if (cmd->cmd_len == 0)
1171 cmd->cmd_len = scsi_command_size(cmd->cmnd);
1172 cmd->cmnd = scsi_req(req)->cmd;
1173 cmd->transfersize = blk_rq_bytes(req);
1174 cmd->allowed = scsi_req(req)->retries;
1179 scsi_device_state_check(struct scsi_device *sdev, struct request *req)
1181 switch (sdev->sdev_state) {
1185 case SDEV_TRANSPORT_OFFLINE:
1187 * If the device is offline we refuse to process any
1188 * commands. The device must be brought online
1189 * before trying any recovery commands.
1191 if (!sdev->offline_already) {
1192 sdev->offline_already = true;
1193 sdev_printk(KERN_ERR, sdev,
1194 "rejecting I/O to offline device\n");
1196 return BLK_STS_IOERR;
1199 * If the device is fully deleted, we refuse to
1200 * process any commands as well.
1202 sdev_printk(KERN_ERR, sdev,
1203 "rejecting I/O to dead device\n");
1204 return BLK_STS_IOERR;
1206 case SDEV_CREATED_BLOCK:
1207 return BLK_STS_RESOURCE;
1210 * If the device is blocked we only accept power management
1213 if (req && WARN_ON_ONCE(!(req->rq_flags & RQF_PM)))
1214 return BLK_STS_RESOURCE;
1218 * For any other not fully online state we only allow
1219 * power management commands.
1221 if (req && !(req->rq_flags & RQF_PM))
1222 return BLK_STS_IOERR;
1228 * scsi_dev_queue_ready: if we can send requests to sdev, assign one token
1229 * and return the token else return -1.
1231 static inline int scsi_dev_queue_ready(struct request_queue *q,
1232 struct scsi_device *sdev)
1236 token = sbitmap_get(&sdev->budget_map);
1237 if (atomic_read(&sdev->device_blocked)) {
1241 if (scsi_device_busy(sdev) > 1)
1245 * unblock after device_blocked iterates to zero
1247 if (atomic_dec_return(&sdev->device_blocked) > 0)
1249 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev,
1250 "unblocking device at zero depth\n"));
1256 sbitmap_put(&sdev->budget_map, token);
1262 * scsi_target_queue_ready: checks if there we can send commands to target
1263 * @sdev: scsi device on starget to check.
1265 static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1266 struct scsi_device *sdev)
1268 struct scsi_target *starget = scsi_target(sdev);
1271 if (starget->single_lun) {
1272 spin_lock_irq(shost->host_lock);
1273 if (starget->starget_sdev_user &&
1274 starget->starget_sdev_user != sdev) {
1275 spin_unlock_irq(shost->host_lock);
1278 starget->starget_sdev_user = sdev;
1279 spin_unlock_irq(shost->host_lock);
1282 if (starget->can_queue <= 0)
1285 busy = atomic_inc_return(&starget->target_busy) - 1;
1286 if (atomic_read(&starget->target_blocked) > 0) {
1291 * unblock after target_blocked iterates to zero
1293 if (atomic_dec_return(&starget->target_blocked) > 0)
1296 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1297 "unblocking target at zero depth\n"));
1300 if (busy >= starget->can_queue)
1306 spin_lock_irq(shost->host_lock);
1307 list_move_tail(&sdev->starved_entry, &shost->starved_list);
1308 spin_unlock_irq(shost->host_lock);
1310 if (starget->can_queue > 0)
1311 atomic_dec(&starget->target_busy);
1316 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1317 * return 0. We must end up running the queue again whenever 0 is
1318 * returned, else IO can hang.
1320 static inline int scsi_host_queue_ready(struct request_queue *q,
1321 struct Scsi_Host *shost,
1322 struct scsi_device *sdev,
1323 struct scsi_cmnd *cmd)
1325 if (scsi_host_in_recovery(shost))
1328 if (atomic_read(&shost->host_blocked) > 0) {
1329 if (scsi_host_busy(shost) > 0)
1333 * unblock after host_blocked iterates to zero
1335 if (atomic_dec_return(&shost->host_blocked) > 0)
1339 shost_printk(KERN_INFO, shost,
1340 "unblocking host at zero depth\n"));
1343 if (shost->host_self_blocked)
1346 /* We're OK to process the command, so we can't be starved */
1347 if (!list_empty(&sdev->starved_entry)) {
1348 spin_lock_irq(shost->host_lock);
1349 if (!list_empty(&sdev->starved_entry))
1350 list_del_init(&sdev->starved_entry);
1351 spin_unlock_irq(shost->host_lock);
1354 __set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1359 spin_lock_irq(shost->host_lock);
1360 if (list_empty(&sdev->starved_entry))
1361 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1362 spin_unlock_irq(shost->host_lock);
1364 scsi_dec_host_busy(shost, cmd);
1369 * Busy state exporting function for request stacking drivers.
1371 * For efficiency, no lock is taken to check the busy state of
1372 * shost/starget/sdev, since the returned value is not guaranteed and
1373 * may be changed after request stacking drivers call the function,
1374 * regardless of taking lock or not.
1376 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1377 * needs to return 'not busy'. Otherwise, request stacking drivers
1378 * may hold requests forever.
1380 static bool scsi_mq_lld_busy(struct request_queue *q)
1382 struct scsi_device *sdev = q->queuedata;
1383 struct Scsi_Host *shost;
1385 if (blk_queue_dying(q))
1391 * Ignore host/starget busy state.
1392 * Since block layer does not have a concept of fairness across
1393 * multiple queues, congestion of host/starget needs to be handled
1396 if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
1403 * Block layer request completion callback. May be called from interrupt
1406 static void scsi_complete(struct request *rq)
1408 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1409 enum scsi_disposition disposition;
1411 INIT_LIST_HEAD(&cmd->eh_entry);
1413 atomic_inc(&cmd->device->iodone_cnt);
1415 atomic_inc(&cmd->device->ioerr_cnt);
1417 disposition = scsi_decide_disposition(cmd);
1418 if (disposition != SUCCESS && scsi_cmd_runtime_exceeced(cmd))
1419 disposition = SUCCESS;
1421 scsi_log_completion(cmd, disposition);
1423 switch (disposition) {
1425 scsi_finish_command(cmd);
1428 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
1430 case ADD_TO_MLQUEUE:
1431 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1434 scsi_eh_scmd_add(cmd);
1440 * scsi_dispatch_cmd - Dispatch a command to the low-level driver.
1441 * @cmd: command block we are dispatching.
1443 * Return: nonzero return request was rejected and device's queue needs to be
1446 static int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
1448 struct Scsi_Host *host = cmd->device->host;
1451 atomic_inc(&cmd->device->iorequest_cnt);
1453 /* check if the device is still usable */
1454 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
1455 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
1456 * returns an immediate error upwards, and signals
1457 * that the device is no longer present */
1458 cmd->result = DID_NO_CONNECT << 16;
1462 /* Check to see if the scsi lld made this device blocked. */
1463 if (unlikely(scsi_device_blocked(cmd->device))) {
1465 * in blocked state, the command is just put back on
1466 * the device queue. The suspend state has already
1467 * blocked the queue so future requests should not
1468 * occur until the device transitions out of the
1471 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1472 "queuecommand : device blocked\n"));
1473 return SCSI_MLQUEUE_DEVICE_BUSY;
1476 /* Store the LUN value in cmnd, if needed. */
1477 if (cmd->device->lun_in_cdb)
1478 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
1479 (cmd->device->lun << 5 & 0xe0);
1484 * Before we queue this command, check if the command
1485 * length exceeds what the host adapter can handle.
1487 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
1488 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1489 "queuecommand : command too long. "
1490 "cdb_size=%d host->max_cmd_len=%d\n",
1491 cmd->cmd_len, cmd->device->host->max_cmd_len));
1492 cmd->result = (DID_ABORT << 16);
1496 if (unlikely(host->shost_state == SHOST_DEL)) {
1497 cmd->result = (DID_NO_CONNECT << 16);
1502 trace_scsi_dispatch_cmd_start(cmd);
1503 rtn = host->hostt->queuecommand(host, cmd);
1505 trace_scsi_dispatch_cmd_error(cmd, rtn);
1506 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
1507 rtn != SCSI_MLQUEUE_TARGET_BUSY)
1508 rtn = SCSI_MLQUEUE_HOST_BUSY;
1510 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1511 "queuecommand : request rejected\n"));
1516 cmd->scsi_done(cmd);
1520 /* Size in bytes of the sg-list stored in the scsi-mq command-private data. */
1521 static unsigned int scsi_mq_inline_sgl_size(struct Scsi_Host *shost)
1523 return min_t(unsigned int, shost->sg_tablesize, SCSI_INLINE_SG_CNT) *
1524 sizeof(struct scatterlist);
1527 static blk_status_t scsi_prepare_cmd(struct request *req)
1529 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1530 struct scsi_device *sdev = req->q->queuedata;
1531 struct Scsi_Host *shost = sdev->host;
1532 struct scatterlist *sg;
1534 scsi_init_command(sdev, cmd);
1537 cmd->tag = req->tag;
1538 cmd->prot_op = SCSI_PROT_NORMAL;
1539 if (blk_rq_bytes(req))
1540 cmd->sc_data_direction = rq_dma_dir(req);
1542 cmd->sc_data_direction = DMA_NONE;
1544 sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
1545 cmd->sdb.table.sgl = sg;
1547 if (scsi_host_get_prot(shost)) {
1548 memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer));
1550 cmd->prot_sdb->table.sgl =
1551 (struct scatterlist *)(cmd->prot_sdb + 1);
1555 * Special handling for passthrough commands, which don't go to the ULP
1558 if (blk_rq_is_passthrough(req))
1559 return scsi_setup_scsi_cmnd(sdev, req);
1561 if (sdev->handler && sdev->handler->prep_fn) {
1562 blk_status_t ret = sdev->handler->prep_fn(sdev, req);
1564 if (ret != BLK_STS_OK)
1568 cmd->cmnd = scsi_req(req)->cmd = scsi_req(req)->__cmd;
1569 memset(cmd->cmnd, 0, BLK_MAX_CDB);
1570 return scsi_cmd_to_driver(cmd)->init_command(cmd);
1573 static void scsi_mq_done(struct scsi_cmnd *cmd)
1575 if (unlikely(blk_should_fake_timeout(cmd->request->q)))
1577 if (unlikely(test_and_set_bit(SCMD_STATE_COMPLETE, &cmd->state)))
1579 trace_scsi_dispatch_cmd_done(cmd);
1580 blk_mq_complete_request(cmd->request);
1583 static void scsi_mq_put_budget(struct request_queue *q, int budget_token)
1585 struct scsi_device *sdev = q->queuedata;
1587 sbitmap_put(&sdev->budget_map, budget_token);
1590 static int scsi_mq_get_budget(struct request_queue *q)
1592 struct scsi_device *sdev = q->queuedata;
1593 int token = scsi_dev_queue_ready(q, sdev);
1598 atomic_inc(&sdev->restarts);
1601 * Orders atomic_inc(&sdev->restarts) and atomic_read(&sdev->device_busy).
1602 * .restarts must be incremented before .device_busy is read because the
1603 * code in scsi_run_queue_async() depends on the order of these operations.
1605 smp_mb__after_atomic();
1608 * If all in-flight requests originated from this LUN are completed
1609 * before reading .device_busy, sdev->device_busy will be observed as
1610 * zero, then blk_mq_delay_run_hw_queues() will dispatch this request
1611 * soon. Otherwise, completion of one of these requests will observe
1612 * the .restarts flag, and the request queue will be run for handling
1613 * this request, see scsi_end_request().
1615 if (unlikely(scsi_device_busy(sdev) == 0 &&
1616 !scsi_device_blocked(sdev)))
1617 blk_mq_delay_run_hw_queues(sdev->request_queue, SCSI_QUEUE_DELAY);
1621 static void scsi_mq_set_rq_budget_token(struct request *req, int token)
1623 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1625 cmd->budget_token = token;
1628 static int scsi_mq_get_rq_budget_token(struct request *req)
1630 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1632 return cmd->budget_token;
1635 static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
1636 const struct blk_mq_queue_data *bd)
1638 struct request *req = bd->rq;
1639 struct request_queue *q = req->q;
1640 struct scsi_device *sdev = q->queuedata;
1641 struct Scsi_Host *shost = sdev->host;
1642 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1646 WARN_ON_ONCE(cmd->budget_token < 0);
1649 * If the device is not in running state we will reject some or all
1652 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
1653 ret = scsi_device_state_check(sdev, req);
1654 if (ret != BLK_STS_OK)
1655 goto out_put_budget;
1658 ret = BLK_STS_RESOURCE;
1659 if (!scsi_target_queue_ready(shost, sdev))
1660 goto out_put_budget;
1661 if (!scsi_host_queue_ready(q, shost, sdev, cmd))
1662 goto out_dec_target_busy;
1664 if (!(req->rq_flags & RQF_DONTPREP)) {
1665 ret = scsi_prepare_cmd(req);
1666 if (ret != BLK_STS_OK)
1667 goto out_dec_host_busy;
1668 req->rq_flags |= RQF_DONTPREP;
1670 clear_bit(SCMD_STATE_COMPLETE, &cmd->state);
1673 cmd->flags &= SCMD_PRESERVED_FLAGS;
1674 if (sdev->simple_tags)
1675 cmd->flags |= SCMD_TAGGED;
1677 cmd->flags |= SCMD_LAST;
1679 scsi_set_resid(cmd, 0);
1680 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
1681 cmd->scsi_done = scsi_mq_done;
1683 blk_mq_start_request(req);
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, cmd);
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(q, cmd->budget_token);
1700 cmd->budget_token = -1;
1704 case BLK_STS_RESOURCE:
1705 case BLK_STS_ZONE_RESOURCE:
1706 if (scsi_device_blocked(sdev))
1707 ret = BLK_STS_DEV_RESOURCE;
1710 scsi_req(req)->result = DID_BUS_BUSY << 16;
1711 if (req->rq_flags & RQF_DONTPREP)
1712 scsi_mq_uninit_cmd(cmd);
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);
1726 scsi_run_queue_async(sdev);
1732 static enum blk_eh_timer_return scsi_timeout(struct request *req,
1736 return BLK_EH_RESET_TIMER;
1737 return scsi_times_out(req);
1740 static int scsi_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
1741 unsigned int hctx_idx, unsigned int numa_node)
1743 struct Scsi_Host *shost = set->driver_data;
1744 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1745 struct scatterlist *sg;
1749 kmem_cache_alloc_node(scsi_sense_cache, GFP_KERNEL, numa_node);
1750 if (!cmd->sense_buffer)
1752 cmd->req.sense = cmd->sense_buffer;
1754 if (scsi_host_get_prot(shost)) {
1755 sg = (void *)cmd + sizeof(struct scsi_cmnd) +
1756 shost->hostt->cmd_size;
1757 cmd->prot_sdb = (void *)sg + scsi_mq_inline_sgl_size(shost);
1760 if (shost->hostt->init_cmd_priv) {
1761 ret = shost->hostt->init_cmd_priv(shost, cmd);
1763 kmem_cache_free(scsi_sense_cache, cmd->sense_buffer);
1769 static void scsi_mq_exit_request(struct blk_mq_tag_set *set, struct request *rq,
1770 unsigned int hctx_idx)
1772 struct Scsi_Host *shost = set->driver_data;
1773 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1775 if (shost->hostt->exit_cmd_priv)
1776 shost->hostt->exit_cmd_priv(shost, cmd);
1777 kmem_cache_free(scsi_sense_cache, cmd->sense_buffer);
1781 static int scsi_mq_poll(struct blk_mq_hw_ctx *hctx)
1783 struct Scsi_Host *shost = hctx->driver_data;
1785 if (shost->hostt->mq_poll)
1786 return shost->hostt->mq_poll(shost, hctx->queue_num);
1791 static int scsi_init_hctx(struct blk_mq_hw_ctx *hctx, void *data,
1792 unsigned int hctx_idx)
1794 struct Scsi_Host *shost = data;
1796 hctx->driver_data = shost;
1800 static int scsi_map_queues(struct blk_mq_tag_set *set)
1802 struct Scsi_Host *shost = container_of(set, struct Scsi_Host, tag_set);
1804 if (shost->hostt->map_queues)
1805 return shost->hostt->map_queues(shost);
1806 return blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]);
1809 void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
1811 struct device *dev = shost->dma_dev;
1814 * this limit is imposed by hardware restrictions
1816 blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
1819 if (scsi_host_prot_dma(shost)) {
1820 shost->sg_prot_tablesize =
1821 min_not_zero(shost->sg_prot_tablesize,
1822 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
1823 BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
1824 blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
1827 if (dev->dma_mask) {
1828 shost->max_sectors = min_t(unsigned int, shost->max_sectors,
1829 dma_max_mapping_size(dev) >> SECTOR_SHIFT);
1831 blk_queue_max_hw_sectors(q, shost->max_sectors);
1832 blk_queue_segment_boundary(q, shost->dma_boundary);
1833 dma_set_seg_boundary(dev, shost->dma_boundary);
1835 blk_queue_max_segment_size(q, shost->max_segment_size);
1836 blk_queue_virt_boundary(q, shost->virt_boundary_mask);
1837 dma_set_max_seg_size(dev, queue_max_segment_size(q));
1840 * Set a reasonable default alignment: The larger of 32-byte (dword),
1841 * which is a common minimum for HBAs, and the minimum DMA alignment,
1842 * which is set by the platform.
1844 * Devices that require a bigger alignment can increase it later.
1846 blk_queue_dma_alignment(q, max(4, dma_get_cache_alignment()) - 1);
1848 EXPORT_SYMBOL_GPL(__scsi_init_queue);
1850 static const struct blk_mq_ops scsi_mq_ops_no_commit = {
1851 .get_budget = scsi_mq_get_budget,
1852 .put_budget = scsi_mq_put_budget,
1853 .queue_rq = scsi_queue_rq,
1854 .complete = scsi_complete,
1855 .timeout = scsi_timeout,
1856 #ifdef CONFIG_BLK_DEBUG_FS
1857 .show_rq = scsi_show_rq,
1859 .init_request = scsi_mq_init_request,
1860 .exit_request = scsi_mq_exit_request,
1861 .initialize_rq_fn = scsi_initialize_rq,
1862 .cleanup_rq = scsi_cleanup_rq,
1863 .busy = scsi_mq_lld_busy,
1864 .map_queues = scsi_map_queues,
1865 .init_hctx = scsi_init_hctx,
1866 .poll = scsi_mq_poll,
1867 .set_rq_budget_token = scsi_mq_set_rq_budget_token,
1868 .get_rq_budget_token = scsi_mq_get_rq_budget_token,
1872 static void scsi_commit_rqs(struct blk_mq_hw_ctx *hctx)
1874 struct Scsi_Host *shost = hctx->driver_data;
1876 shost->hostt->commit_rqs(shost, hctx->queue_num);
1879 static const struct blk_mq_ops scsi_mq_ops = {
1880 .get_budget = scsi_mq_get_budget,
1881 .put_budget = scsi_mq_put_budget,
1882 .queue_rq = scsi_queue_rq,
1883 .commit_rqs = scsi_commit_rqs,
1884 .complete = scsi_complete,
1885 .timeout = scsi_timeout,
1886 #ifdef CONFIG_BLK_DEBUG_FS
1887 .show_rq = scsi_show_rq,
1889 .init_request = scsi_mq_init_request,
1890 .exit_request = scsi_mq_exit_request,
1891 .initialize_rq_fn = scsi_initialize_rq,
1892 .cleanup_rq = scsi_cleanup_rq,
1893 .busy = scsi_mq_lld_busy,
1894 .map_queues = scsi_map_queues,
1895 .init_hctx = scsi_init_hctx,
1896 .poll = scsi_mq_poll,
1897 .set_rq_budget_token = scsi_mq_set_rq_budget_token,
1898 .get_rq_budget_token = scsi_mq_get_rq_budget_token,
1901 int scsi_mq_setup_tags(struct Scsi_Host *shost)
1903 unsigned int cmd_size, sgl_size;
1904 struct blk_mq_tag_set *tag_set = &shost->tag_set;
1906 sgl_size = max_t(unsigned int, sizeof(struct scatterlist),
1907 scsi_mq_inline_sgl_size(shost));
1908 cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size;
1909 if (scsi_host_get_prot(shost))
1910 cmd_size += sizeof(struct scsi_data_buffer) +
1911 sizeof(struct scatterlist) * SCSI_INLINE_PROT_SG_CNT;
1913 memset(tag_set, 0, sizeof(*tag_set));
1914 if (shost->hostt->commit_rqs)
1915 tag_set->ops = &scsi_mq_ops;
1917 tag_set->ops = &scsi_mq_ops_no_commit;
1918 tag_set->nr_hw_queues = shost->nr_hw_queues ? : 1;
1919 tag_set->nr_maps = shost->nr_maps ? : 1;
1920 tag_set->queue_depth = shost->can_queue;
1921 tag_set->cmd_size = cmd_size;
1922 tag_set->numa_node = NUMA_NO_NODE;
1923 tag_set->flags = BLK_MQ_F_SHOULD_MERGE;
1925 BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
1926 tag_set->driver_data = shost;
1927 if (shost->host_tagset)
1928 tag_set->flags |= BLK_MQ_F_TAG_HCTX_SHARED;
1930 return blk_mq_alloc_tag_set(tag_set);
1933 void scsi_mq_destroy_tags(struct Scsi_Host *shost)
1935 blk_mq_free_tag_set(&shost->tag_set);
1939 * scsi_device_from_queue - return sdev associated with a request_queue
1940 * @q: The request queue to return the sdev from
1942 * Return the sdev associated with a request queue or NULL if the
1943 * request_queue does not reference a SCSI device.
1945 struct scsi_device *scsi_device_from_queue(struct request_queue *q)
1947 struct scsi_device *sdev = NULL;
1949 if (q->mq_ops == &scsi_mq_ops_no_commit ||
1950 q->mq_ops == &scsi_mq_ops)
1951 sdev = q->queuedata;
1952 if (!sdev || !get_device(&sdev->sdev_gendev))
1959 * scsi_block_requests - Utility function used by low-level drivers to prevent
1960 * further commands from being queued to the device.
1961 * @shost: host in question
1963 * There is no timer nor any other means by which the requests get unblocked
1964 * other than the low-level driver calling scsi_unblock_requests().
1966 void scsi_block_requests(struct Scsi_Host *shost)
1968 shost->host_self_blocked = 1;
1970 EXPORT_SYMBOL(scsi_block_requests);
1973 * scsi_unblock_requests - Utility function used by low-level drivers to allow
1974 * further commands to be queued to the device.
1975 * @shost: host in question
1977 * There is no timer nor any other means by which the requests get unblocked
1978 * other than the low-level driver calling scsi_unblock_requests(). This is done
1979 * as an API function so that changes to the internals of the scsi mid-layer
1980 * won't require wholesale changes to drivers that use this feature.
1982 void scsi_unblock_requests(struct Scsi_Host *shost)
1984 shost->host_self_blocked = 0;
1985 scsi_run_host_queues(shost);
1987 EXPORT_SYMBOL(scsi_unblock_requests);
1989 void scsi_exit_queue(void)
1991 kmem_cache_destroy(scsi_sense_cache);
1995 * scsi_mode_select - issue a mode select
1996 * @sdev: SCSI device to be queried
1997 * @pf: Page format bit (1 == standard, 0 == vendor specific)
1998 * @sp: Save page bit (0 == don't save, 1 == save)
1999 * @modepage: mode page being requested
2000 * @buffer: request buffer (may not be smaller than eight bytes)
2001 * @len: length of request buffer.
2002 * @timeout: command timeout
2003 * @retries: number of retries before failing
2004 * @data: returns a structure abstracting the mode header data
2005 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2006 * must be SCSI_SENSE_BUFFERSIZE big.
2008 * Returns zero if successful; negative error number or scsi
2013 scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
2014 unsigned char *buffer, int len, int timeout, int retries,
2015 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2017 unsigned char cmd[10];
2018 unsigned char *real_buffer;
2021 memset(cmd, 0, sizeof(cmd));
2022 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
2024 if (sdev->use_10_for_ms) {
2027 real_buffer = kmalloc(8 + len, GFP_KERNEL);
2030 memcpy(real_buffer + 8, buffer, len);
2034 real_buffer[2] = data->medium_type;
2035 real_buffer[3] = data->device_specific;
2036 real_buffer[4] = data->longlba ? 0x01 : 0;
2038 real_buffer[6] = data->block_descriptor_length >> 8;
2039 real_buffer[7] = data->block_descriptor_length;
2041 cmd[0] = MODE_SELECT_10;
2045 if (len > 255 || data->block_descriptor_length > 255 ||
2049 real_buffer = kmalloc(4 + len, GFP_KERNEL);
2052 memcpy(real_buffer + 4, buffer, len);
2055 real_buffer[1] = data->medium_type;
2056 real_buffer[2] = data->device_specific;
2057 real_buffer[3] = data->block_descriptor_length;
2059 cmd[0] = MODE_SELECT;
2063 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
2064 sshdr, timeout, retries, NULL);
2068 EXPORT_SYMBOL_GPL(scsi_mode_select);
2071 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
2072 * @sdev: SCSI device to be queried
2073 * @dbd: set if mode sense will allow block descriptors to be returned
2074 * @modepage: mode page being requested
2075 * @buffer: request buffer (may not be smaller than eight bytes)
2076 * @len: length of request buffer.
2077 * @timeout: command timeout
2078 * @retries: number of retries before failing
2079 * @data: returns a structure abstracting the mode header data
2080 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2081 * must be SCSI_SENSE_BUFFERSIZE big.
2083 * Returns zero if successful, or a negative error number on failure
2086 scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
2087 unsigned char *buffer, int len, int timeout, int retries,
2088 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2090 unsigned char cmd[12];
2093 int result, retry_count = retries;
2094 struct scsi_sense_hdr my_sshdr;
2096 memset(data, 0, sizeof(*data));
2097 memset(&cmd[0], 0, 12);
2099 dbd = sdev->set_dbd_for_ms ? 8 : dbd;
2100 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
2103 /* caller might not be interested in sense, but we need it */
2108 use_10_for_ms = sdev->use_10_for_ms;
2110 if (use_10_for_ms) {
2114 cmd[0] = MODE_SENSE_10;
2121 cmd[0] = MODE_SENSE;
2126 memset(buffer, 0, len);
2128 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
2129 sshdr, timeout, retries, NULL);
2133 /* This code looks awful: what it's doing is making sure an
2134 * ILLEGAL REQUEST sense return identifies the actual command
2135 * byte as the problem. MODE_SENSE commands can return
2136 * ILLEGAL REQUEST if the code page isn't supported */
2138 if (!scsi_status_is_good(result)) {
2139 if (scsi_sense_valid(sshdr)) {
2140 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
2141 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
2143 * Invalid command operation code
2145 if (use_10_for_ms) {
2146 sdev->use_10_for_ms = 0;
2150 if (scsi_status_is_check_condition(result) &&
2151 sshdr->sense_key == UNIT_ATTENTION &&
2159 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
2160 (modepage == 6 || modepage == 8))) {
2161 /* Initio breakage? */
2164 data->medium_type = 0;
2165 data->device_specific = 0;
2167 data->block_descriptor_length = 0;
2168 } else if (use_10_for_ms) {
2169 data->length = buffer[0]*256 + buffer[1] + 2;
2170 data->medium_type = buffer[2];
2171 data->device_specific = buffer[3];
2172 data->longlba = buffer[4] & 0x01;
2173 data->block_descriptor_length = buffer[6]*256
2176 data->length = buffer[0] + 1;
2177 data->medium_type = buffer[1];
2178 data->device_specific = buffer[2];
2179 data->block_descriptor_length = buffer[3];
2181 data->header_length = header_length;
2185 EXPORT_SYMBOL(scsi_mode_sense);
2188 * scsi_test_unit_ready - test if unit is ready
2189 * @sdev: scsi device to change the state of.
2190 * @timeout: command timeout
2191 * @retries: number of retries before failing
2192 * @sshdr: outpout pointer for decoded sense information.
2194 * Returns zero if unsuccessful or an error if TUR failed. For
2195 * removable media, UNIT_ATTENTION sets ->changed flag.
2198 scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2199 struct scsi_sense_hdr *sshdr)
2202 TEST_UNIT_READY, 0, 0, 0, 0, 0,
2206 /* try to eat the UNIT_ATTENTION if there are enough retries */
2208 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
2210 if (sdev->removable && scsi_sense_valid(sshdr) &&
2211 sshdr->sense_key == UNIT_ATTENTION)
2213 } while (scsi_sense_valid(sshdr) &&
2214 sshdr->sense_key == UNIT_ATTENTION && --retries);
2218 EXPORT_SYMBOL(scsi_test_unit_ready);
2221 * scsi_device_set_state - Take the given device through the device state model.
2222 * @sdev: scsi device to change the state of.
2223 * @state: state to change to.
2225 * Returns zero if successful or an error if the requested
2226 * transition is illegal.
2229 scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2231 enum scsi_device_state oldstate = sdev->sdev_state;
2233 if (state == oldstate)
2239 case SDEV_CREATED_BLOCK:
2250 case SDEV_TRANSPORT_OFFLINE:
2263 case SDEV_TRANSPORT_OFFLINE:
2271 case SDEV_TRANSPORT_OFFLINE:
2286 case SDEV_CREATED_BLOCK:
2295 case SDEV_CREATED_BLOCK:
2310 case SDEV_TRANSPORT_OFFLINE:
2322 case SDEV_TRANSPORT_OFFLINE:
2325 case SDEV_CREATED_BLOCK:
2333 sdev->offline_already = false;
2334 sdev->sdev_state = state;
2338 SCSI_LOG_ERROR_RECOVERY(1,
2339 sdev_printk(KERN_ERR, sdev,
2340 "Illegal state transition %s->%s",
2341 scsi_device_state_name(oldstate),
2342 scsi_device_state_name(state))
2346 EXPORT_SYMBOL(scsi_device_set_state);
2349 * scsi_evt_emit - emit a single SCSI device uevent
2350 * @sdev: associated SCSI device
2351 * @evt: event to emit
2353 * Send a single uevent (scsi_event) to the associated scsi_device.
2355 static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2360 switch (evt->evt_type) {
2361 case SDEV_EVT_MEDIA_CHANGE:
2362 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2364 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2365 scsi_rescan_device(&sdev->sdev_gendev);
2366 envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2368 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2369 envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2371 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2372 envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2374 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2375 envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2377 case SDEV_EVT_LUN_CHANGE_REPORTED:
2378 envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2380 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2381 envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
2383 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2384 envp[idx++] = "SDEV_UA=POWER_ON_RESET_OCCURRED";
2393 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2397 * scsi_evt_thread - send a uevent for each scsi event
2398 * @work: work struct for scsi_device
2400 * Dispatch queued events to their associated scsi_device kobjects
2403 void scsi_evt_thread(struct work_struct *work)
2405 struct scsi_device *sdev;
2406 enum scsi_device_event evt_type;
2407 LIST_HEAD(event_list);
2409 sdev = container_of(work, struct scsi_device, event_work);
2411 for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
2412 if (test_and_clear_bit(evt_type, sdev->pending_events))
2413 sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
2416 struct scsi_event *evt;
2417 struct list_head *this, *tmp;
2418 unsigned long flags;
2420 spin_lock_irqsave(&sdev->list_lock, flags);
2421 list_splice_init(&sdev->event_list, &event_list);
2422 spin_unlock_irqrestore(&sdev->list_lock, flags);
2424 if (list_empty(&event_list))
2427 list_for_each_safe(this, tmp, &event_list) {
2428 evt = list_entry(this, struct scsi_event, node);
2429 list_del(&evt->node);
2430 scsi_evt_emit(sdev, evt);
2437 * sdev_evt_send - send asserted event to uevent thread
2438 * @sdev: scsi_device event occurred on
2439 * @evt: event to send
2441 * Assert scsi device event asynchronously.
2443 void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2445 unsigned long flags;
2448 /* FIXME: currently this check eliminates all media change events
2449 * for polled devices. Need to update to discriminate between AN
2450 * and polled events */
2451 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2457 spin_lock_irqsave(&sdev->list_lock, flags);
2458 list_add_tail(&evt->node, &sdev->event_list);
2459 schedule_work(&sdev->event_work);
2460 spin_unlock_irqrestore(&sdev->list_lock, flags);
2462 EXPORT_SYMBOL_GPL(sdev_evt_send);
2465 * sdev_evt_alloc - allocate a new scsi event
2466 * @evt_type: type of event to allocate
2467 * @gfpflags: GFP flags for allocation
2469 * Allocates and returns a new scsi_event.
2471 struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2474 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2478 evt->evt_type = evt_type;
2479 INIT_LIST_HEAD(&evt->node);
2481 /* evt_type-specific initialization, if any */
2483 case SDEV_EVT_MEDIA_CHANGE:
2484 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2485 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2486 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2487 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2488 case SDEV_EVT_LUN_CHANGE_REPORTED:
2489 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2490 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2498 EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2501 * sdev_evt_send_simple - send asserted event to uevent thread
2502 * @sdev: scsi_device event occurred on
2503 * @evt_type: type of event to send
2504 * @gfpflags: GFP flags for allocation
2506 * Assert scsi device event asynchronously, given an event type.
2508 void sdev_evt_send_simple(struct scsi_device *sdev,
2509 enum scsi_device_event evt_type, gfp_t gfpflags)
2511 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2513 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2518 sdev_evt_send(sdev, evt);
2520 EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2523 * scsi_device_quiesce - Block all commands except power management.
2524 * @sdev: scsi device to quiesce.
2526 * This works by trying to transition to the SDEV_QUIESCE state
2527 * (which must be a legal transition). When the device is in this
2528 * state, only power management requests will be accepted, all others will
2531 * Must be called with user context, may sleep.
2533 * Returns zero if unsuccessful or an error if not.
2536 scsi_device_quiesce(struct scsi_device *sdev)
2538 struct request_queue *q = sdev->request_queue;
2542 * It is allowed to call scsi_device_quiesce() multiple times from
2543 * the same context but concurrent scsi_device_quiesce() calls are
2546 WARN_ON_ONCE(sdev->quiesced_by && sdev->quiesced_by != current);
2548 if (sdev->quiesced_by == current)
2553 blk_mq_freeze_queue(q);
2555 * Ensure that the effect of blk_set_pm_only() will be visible
2556 * for percpu_ref_tryget() callers that occur after the queue
2557 * unfreeze even if the queue was already frozen before this function
2558 * was called. See also https://lwn.net/Articles/573497/.
2561 blk_mq_unfreeze_queue(q);
2563 mutex_lock(&sdev->state_mutex);
2564 err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2566 sdev->quiesced_by = current;
2568 blk_clear_pm_only(q);
2569 mutex_unlock(&sdev->state_mutex);
2573 EXPORT_SYMBOL(scsi_device_quiesce);
2576 * scsi_device_resume - Restart user issued commands to a quiesced device.
2577 * @sdev: scsi device to resume.
2579 * Moves the device from quiesced back to running and restarts the
2582 * Must be called with user context, may sleep.
2584 void scsi_device_resume(struct scsi_device *sdev)
2586 /* check if the device state was mutated prior to resume, and if
2587 * so assume the state is being managed elsewhere (for example
2588 * device deleted during suspend)
2590 mutex_lock(&sdev->state_mutex);
2591 if (sdev->sdev_state == SDEV_QUIESCE)
2592 scsi_device_set_state(sdev, SDEV_RUNNING);
2593 if (sdev->quiesced_by) {
2594 sdev->quiesced_by = NULL;
2595 blk_clear_pm_only(sdev->request_queue);
2597 mutex_unlock(&sdev->state_mutex);
2599 EXPORT_SYMBOL(scsi_device_resume);
2602 device_quiesce_fn(struct scsi_device *sdev, void *data)
2604 scsi_device_quiesce(sdev);
2608 scsi_target_quiesce(struct scsi_target *starget)
2610 starget_for_each_device(starget, NULL, device_quiesce_fn);
2612 EXPORT_SYMBOL(scsi_target_quiesce);
2615 device_resume_fn(struct scsi_device *sdev, void *data)
2617 scsi_device_resume(sdev);
2621 scsi_target_resume(struct scsi_target *starget)
2623 starget_for_each_device(starget, NULL, device_resume_fn);
2625 EXPORT_SYMBOL(scsi_target_resume);
2628 * scsi_internal_device_block_nowait - try to transition to the SDEV_BLOCK state
2629 * @sdev: device to block
2631 * Pause SCSI command processing on the specified device. Does not sleep.
2633 * Returns zero if successful or a negative error code upon failure.
2636 * This routine transitions the device to the SDEV_BLOCK state (which must be
2637 * a legal transition). When the device is in this state, command processing
2638 * is paused until the device leaves the SDEV_BLOCK state. See also
2639 * scsi_internal_device_unblock_nowait().
2641 int scsi_internal_device_block_nowait(struct scsi_device *sdev)
2643 struct request_queue *q = sdev->request_queue;
2646 err = scsi_device_set_state(sdev, SDEV_BLOCK);
2648 err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2655 * The device has transitioned to SDEV_BLOCK. Stop the
2656 * block layer from calling the midlayer with this device's
2659 blk_mq_quiesce_queue_nowait(q);
2662 EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait);
2665 * scsi_internal_device_block - try to transition to the SDEV_BLOCK state
2666 * @sdev: device to block
2668 * Pause SCSI command processing on the specified device and wait until all
2669 * ongoing scsi_request_fn() / scsi_queue_rq() calls have finished. May sleep.
2671 * Returns zero if successful or a negative error code upon failure.
2674 * This routine transitions the device to the SDEV_BLOCK state (which must be
2675 * a legal transition). When the device is in this state, command processing
2676 * is paused until the device leaves the SDEV_BLOCK state. See also
2677 * scsi_internal_device_unblock().
2679 static int scsi_internal_device_block(struct scsi_device *sdev)
2681 struct request_queue *q = sdev->request_queue;
2684 mutex_lock(&sdev->state_mutex);
2685 err = scsi_internal_device_block_nowait(sdev);
2687 blk_mq_quiesce_queue(q);
2688 mutex_unlock(&sdev->state_mutex);
2693 void scsi_start_queue(struct scsi_device *sdev)
2695 struct request_queue *q = sdev->request_queue;
2697 blk_mq_unquiesce_queue(q);
2701 * scsi_internal_device_unblock_nowait - resume a device after a block request
2702 * @sdev: device to resume
2703 * @new_state: state to set the device to after unblocking
2705 * Restart the device queue for a previously suspended SCSI device. Does not
2708 * Returns zero if successful or a negative error code upon failure.
2711 * This routine transitions the device to the SDEV_RUNNING state or to one of
2712 * the offline states (which must be a legal transition) allowing the midlayer
2713 * to goose the queue for this device.
2715 int scsi_internal_device_unblock_nowait(struct scsi_device *sdev,
2716 enum scsi_device_state new_state)
2718 switch (new_state) {
2720 case SDEV_TRANSPORT_OFFLINE:
2727 * Try to transition the scsi device to SDEV_RUNNING or one of the
2728 * offlined states and goose the device queue if successful.
2730 switch (sdev->sdev_state) {
2732 case SDEV_TRANSPORT_OFFLINE:
2733 sdev->sdev_state = new_state;
2735 case SDEV_CREATED_BLOCK:
2736 if (new_state == SDEV_TRANSPORT_OFFLINE ||
2737 new_state == SDEV_OFFLINE)
2738 sdev->sdev_state = new_state;
2740 sdev->sdev_state = SDEV_CREATED;
2748 scsi_start_queue(sdev);
2752 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock_nowait);
2755 * scsi_internal_device_unblock - resume a device after a block request
2756 * @sdev: device to resume
2757 * @new_state: state to set the device to after unblocking
2759 * Restart the device queue for a previously suspended SCSI device. May sleep.
2761 * Returns zero if successful or a negative error code upon failure.
2764 * This routine transitions the device to the SDEV_RUNNING state or to one of
2765 * the offline states (which must be a legal transition) allowing the midlayer
2766 * to goose the queue for this device.
2768 static int scsi_internal_device_unblock(struct scsi_device *sdev,
2769 enum scsi_device_state new_state)
2773 mutex_lock(&sdev->state_mutex);
2774 ret = scsi_internal_device_unblock_nowait(sdev, new_state);
2775 mutex_unlock(&sdev->state_mutex);
2781 device_block(struct scsi_device *sdev, void *data)
2785 ret = scsi_internal_device_block(sdev);
2787 WARN_ONCE(ret, "scsi_internal_device_block(%s) failed: ret = %d\n",
2788 dev_name(&sdev->sdev_gendev), ret);
2792 target_block(struct device *dev, void *data)
2794 if (scsi_is_target_device(dev))
2795 starget_for_each_device(to_scsi_target(dev), NULL,
2801 scsi_target_block(struct device *dev)
2803 if (scsi_is_target_device(dev))
2804 starget_for_each_device(to_scsi_target(dev), NULL,
2807 device_for_each_child(dev, NULL, target_block);
2809 EXPORT_SYMBOL_GPL(scsi_target_block);
2812 device_unblock(struct scsi_device *sdev, void *data)
2814 scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
2818 target_unblock(struct device *dev, void *data)
2820 if (scsi_is_target_device(dev))
2821 starget_for_each_device(to_scsi_target(dev), data,
2827 scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
2829 if (scsi_is_target_device(dev))
2830 starget_for_each_device(to_scsi_target(dev), &new_state,
2833 device_for_each_child(dev, &new_state, target_unblock);
2835 EXPORT_SYMBOL_GPL(scsi_target_unblock);
2838 scsi_host_block(struct Scsi_Host *shost)
2840 struct scsi_device *sdev;
2844 * Call scsi_internal_device_block_nowait so we can avoid
2845 * calling synchronize_rcu() for each LUN.
2847 shost_for_each_device(sdev, shost) {
2848 mutex_lock(&sdev->state_mutex);
2849 ret = scsi_internal_device_block_nowait(sdev);
2850 mutex_unlock(&sdev->state_mutex);
2852 scsi_device_put(sdev);
2858 * SCSI never enables blk-mq's BLK_MQ_F_BLOCKING flag so
2859 * calling synchronize_rcu() once is enough.
2861 WARN_ON_ONCE(shost->tag_set.flags & BLK_MQ_F_BLOCKING);
2868 EXPORT_SYMBOL_GPL(scsi_host_block);
2871 scsi_host_unblock(struct Scsi_Host *shost, int new_state)
2873 struct scsi_device *sdev;
2876 shost_for_each_device(sdev, shost) {
2877 ret = scsi_internal_device_unblock(sdev, new_state);
2879 scsi_device_put(sdev);
2885 EXPORT_SYMBOL_GPL(scsi_host_unblock);
2888 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
2889 * @sgl: scatter-gather list
2890 * @sg_count: number of segments in sg
2891 * @offset: offset in bytes into sg, on return offset into the mapped area
2892 * @len: bytes to map, on return number of bytes mapped
2894 * Returns virtual address of the start of the mapped page
2896 void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
2897 size_t *offset, size_t *len)
2900 size_t sg_len = 0, len_complete = 0;
2901 struct scatterlist *sg;
2904 WARN_ON(!irqs_disabled());
2906 for_each_sg(sgl, sg, sg_count, i) {
2907 len_complete = sg_len; /* Complete sg-entries */
2908 sg_len += sg->length;
2909 if (sg_len > *offset)
2913 if (unlikely(i == sg_count)) {
2914 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
2916 __func__, sg_len, *offset, sg_count);
2921 /* Offset starting from the beginning of first page in this sg-entry */
2922 *offset = *offset - len_complete + sg->offset;
2924 /* Assumption: contiguous pages can be accessed as "page + i" */
2925 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
2926 *offset &= ~PAGE_MASK;
2928 /* Bytes in this sg-entry from *offset to the end of the page */
2929 sg_len = PAGE_SIZE - *offset;
2933 return kmap_atomic(page);
2935 EXPORT_SYMBOL(scsi_kmap_atomic_sg);
2938 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
2939 * @virt: virtual address to be unmapped
2941 void scsi_kunmap_atomic_sg(void *virt)
2943 kunmap_atomic(virt);
2945 EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
2947 void sdev_disable_disk_events(struct scsi_device *sdev)
2949 atomic_inc(&sdev->disk_events_disable_depth);
2951 EXPORT_SYMBOL(sdev_disable_disk_events);
2953 void sdev_enable_disk_events(struct scsi_device *sdev)
2955 if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0))
2957 atomic_dec(&sdev->disk_events_disable_depth);
2959 EXPORT_SYMBOL(sdev_enable_disk_events);
2961 static unsigned char designator_prio(const unsigned char *d)
2964 /* not associated with LUN */
2968 /* invalid length */
2972 * Order of preference for lun descriptor:
2973 * - SCSI name string
2974 * - NAA IEEE Registered Extended
2975 * - EUI-64 based 16-byte
2976 * - EUI-64 based 12-byte
2977 * - NAA IEEE Registered
2978 * - NAA IEEE Extended
2979 * - EUI-64 based 8-byte
2980 * - SCSI name string (truncated)
2982 * as longer descriptors reduce the likelyhood
2983 * of identification clashes.
2986 switch (d[1] & 0xf) {
2988 /* SCSI name string, variable-length UTF-8 */
2991 switch (d[4] >> 4) {
2993 /* NAA registered extended */
2996 /* NAA registered */
3002 /* NAA locally assigned */
3011 /* EUI64-based, 16 byte */
3014 /* EUI64-based, 12 byte */
3017 /* EUI64-based, 8 byte */
3034 * scsi_vpd_lun_id - return a unique device identification
3035 * @sdev: SCSI device
3036 * @id: buffer for the identification
3037 * @id_len: length of the buffer
3039 * Copies a unique device identification into @id based
3040 * on the information in the VPD page 0x83 of the device.
3041 * The string will be formatted as a SCSI name string.
3043 * Returns the length of the identification or error on failure.
3044 * If the identifier is longer than the supplied buffer the actual
3045 * identifier length is returned and the buffer is not zero-padded.
3047 int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len)
3051 const unsigned char *d, *cur_id_str;
3052 const struct scsi_vpd *vpd_pg83;
3053 int id_size = -EINVAL;
3056 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3062 /* The id string must be at least 20 bytes + terminating NULL byte */
3068 memset(id, 0, id_len);
3069 for (d = vpd_pg83->data + 4;
3070 d < vpd_pg83->data + vpd_pg83->len;
3072 u8 prio = designator_prio(d);
3074 if (prio == 0 || cur_id_prio > prio)
3077 switch (d[1] & 0xf) {
3080 if (cur_id_size > d[3])
3084 if (cur_id_size + 4 > id_len)
3085 cur_id_size = id_len - 4;
3087 id_size = snprintf(id, id_len, "t10.%*pE",
3088 cur_id_size, cur_id_str);
3095 switch (cur_id_size) {
3097 id_size = snprintf(id, id_len,
3102 id_size = snprintf(id, id_len,
3107 id_size = snprintf(id, id_len,
3120 switch (cur_id_size) {
3122 id_size = snprintf(id, id_len,
3127 id_size = snprintf(id, id_len,
3136 /* SCSI name string */
3137 if (cur_id_size > d[3])
3139 /* Prefer others for truncated descriptor */
3140 if (d[3] > id_len) {
3142 if (cur_id_prio > prio)
3146 cur_id_size = id_size = d[3];
3148 if (cur_id_size >= id_len)
3149 cur_id_size = id_len - 1;
3150 memcpy(id, cur_id_str, cur_id_size);
3160 EXPORT_SYMBOL(scsi_vpd_lun_id);
3163 * scsi_vpd_tpg_id - return a target port group identifier
3164 * @sdev: SCSI device
3166 * Returns the Target Port Group identifier from the information
3167 * froom VPD page 0x83 of the device.
3169 * Returns the identifier or error on failure.
3171 int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id)
3173 const unsigned char *d;
3174 const struct scsi_vpd *vpd_pg83;
3175 int group_id = -EAGAIN, rel_port = -1;
3178 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3184 d = vpd_pg83->data + 4;
3185 while (d < vpd_pg83->data + vpd_pg83->len) {
3186 switch (d[1] & 0xf) {
3188 /* Relative target port */
3189 rel_port = get_unaligned_be16(&d[6]);
3192 /* Target port group */
3193 group_id = get_unaligned_be16(&d[6]);
3202 if (group_id >= 0 && rel_id && rel_port != -1)
3207 EXPORT_SYMBOL(scsi_vpd_tpg_id);
3210 * scsi_build_sense - build sense data for a command
3211 * @scmd: scsi command for which the sense should be formatted
3212 * @desc: Sense format (non-zero == descriptor format,
3213 * 0 == fixed format)
3215 * @asc: Additional sense code
3216 * @ascq: Additional sense code qualifier
3219 void scsi_build_sense(struct scsi_cmnd *scmd, int desc, u8 key, u8 asc, u8 ascq)
3221 scsi_build_sense_buffer(desc, scmd->sense_buffer, key, asc, ascq);
3222 scmd->result = SAM_STAT_CHECK_CONDITION;
3224 EXPORT_SYMBOL_GPL(scsi_build_sense);