2 * Copyright (C) 1999 Eric Youngdale
3 * Copyright (C) 2014 Christoph Hellwig
5 * SCSI queueing library.
6 * Initial versions: Eric Youngdale (eric@andante.org).
7 * Based upon conversations with large numbers
8 * of people at Linux Expo.
11 #include <linux/bio.h>
12 #include <linux/bitops.h>
13 #include <linux/blkdev.h>
14 #include <linux/completion.h>
15 #include <linux/kernel.h>
16 #include <linux/export.h>
17 #include <linux/init.h>
18 #include <linux/pci.h>
19 #include <linux/delay.h>
20 #include <linux/hardirq.h>
21 #include <linux/scatterlist.h>
22 #include <linux/blk-mq.h>
23 #include <linux/ratelimit.h>
24 #include <asm/unaligned.h>
26 #include <scsi/scsi.h>
27 #include <scsi/scsi_cmnd.h>
28 #include <scsi/scsi_dbg.h>
29 #include <scsi/scsi_device.h>
30 #include <scsi/scsi_driver.h>
31 #include <scsi/scsi_eh.h>
32 #include <scsi/scsi_host.h>
33 #include <scsi/scsi_transport.h> /* __scsi_init_queue() */
34 #include <scsi/scsi_dh.h>
36 #include <trace/events/scsi.h>
38 #include "scsi_debugfs.h"
39 #include "scsi_priv.h"
40 #include "scsi_logging.h"
42 static struct kmem_cache *scsi_sdb_cache;
43 static struct kmem_cache *scsi_sense_cache;
44 static struct kmem_cache *scsi_sense_isadma_cache;
45 static DEFINE_MUTEX(scsi_sense_cache_mutex);
47 static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd);
49 static inline struct kmem_cache *
50 scsi_select_sense_cache(bool unchecked_isa_dma)
52 return unchecked_isa_dma ? scsi_sense_isadma_cache : scsi_sense_cache;
55 static void scsi_free_sense_buffer(bool unchecked_isa_dma,
56 unsigned char *sense_buffer)
58 kmem_cache_free(scsi_select_sense_cache(unchecked_isa_dma),
62 static unsigned char *scsi_alloc_sense_buffer(bool unchecked_isa_dma,
63 gfp_t gfp_mask, int numa_node)
65 return kmem_cache_alloc_node(scsi_select_sense_cache(unchecked_isa_dma),
69 int scsi_init_sense_cache(struct Scsi_Host *shost)
71 struct kmem_cache *cache;
74 cache = scsi_select_sense_cache(shost->unchecked_isa_dma);
78 mutex_lock(&scsi_sense_cache_mutex);
79 if (shost->unchecked_isa_dma) {
80 scsi_sense_isadma_cache =
81 kmem_cache_create("scsi_sense_cache(DMA)",
82 SCSI_SENSE_BUFFERSIZE, 0,
83 SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA, NULL);
84 if (!scsi_sense_isadma_cache)
88 kmem_cache_create("scsi_sense_cache",
89 SCSI_SENSE_BUFFERSIZE, 0, SLAB_HWCACHE_ALIGN, NULL);
90 if (!scsi_sense_cache)
94 mutex_unlock(&scsi_sense_cache_mutex);
99 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
100 * not change behaviour from the previous unplug mechanism, experimentation
101 * may prove this needs changing.
103 #define SCSI_QUEUE_DELAY 3
106 scsi_set_blocked(struct scsi_cmnd *cmd, int reason)
108 struct Scsi_Host *host = cmd->device->host;
109 struct scsi_device *device = cmd->device;
110 struct scsi_target *starget = scsi_target(device);
113 * Set the appropriate busy bit for the device/host.
115 * If the host/device isn't busy, assume that something actually
116 * completed, and that we should be able to queue a command now.
118 * Note that the prior mid-layer assumption that any host could
119 * always queue at least one command is now broken. The mid-layer
120 * will implement a user specifiable stall (see
121 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
122 * if a command is requeued with no other commands outstanding
123 * either for the device or for the host.
126 case SCSI_MLQUEUE_HOST_BUSY:
127 atomic_set(&host->host_blocked, host->max_host_blocked);
129 case SCSI_MLQUEUE_DEVICE_BUSY:
130 case SCSI_MLQUEUE_EH_RETRY:
131 atomic_set(&device->device_blocked,
132 device->max_device_blocked);
134 case SCSI_MLQUEUE_TARGET_BUSY:
135 atomic_set(&starget->target_blocked,
136 starget->max_target_blocked);
141 static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd)
143 struct scsi_device *sdev = cmd->device;
145 if (cmd->request->rq_flags & RQF_DONTPREP) {
146 cmd->request->rq_flags &= ~RQF_DONTPREP;
147 scsi_mq_uninit_cmd(cmd);
151 blk_mq_requeue_request(cmd->request, true);
152 put_device(&sdev->sdev_gendev);
156 * __scsi_queue_insert - private queue insertion
157 * @cmd: The SCSI command being requeued
158 * @reason: The reason for the requeue
159 * @unbusy: Whether the queue should be unbusied
161 * This is a private queue insertion. The public interface
162 * scsi_queue_insert() always assumes the queue should be unbusied
163 * because it's always called before the completion. This function is
164 * for a requeue after completion, which should only occur in this
167 static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy)
169 struct scsi_device *device = cmd->device;
170 struct request_queue *q = device->request_queue;
173 SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd,
174 "Inserting command %p into mlqueue\n", cmd));
176 scsi_set_blocked(cmd, reason);
179 * Decrement the counters, since these commands are no longer
180 * active on the host/device.
183 scsi_device_unbusy(device);
186 * Requeue this command. It will go before all other commands
187 * that are already in the queue. Schedule requeue work under
188 * lock such that the kblockd_schedule_work() call happens
189 * before blk_cleanup_queue() finishes.
193 scsi_mq_requeue_cmd(cmd);
196 spin_lock_irqsave(q->queue_lock, flags);
197 blk_requeue_request(q, cmd->request);
198 kblockd_schedule_work(&device->requeue_work);
199 spin_unlock_irqrestore(q->queue_lock, flags);
203 * Function: scsi_queue_insert()
205 * Purpose: Insert a command in the midlevel queue.
207 * Arguments: cmd - command that we are adding to queue.
208 * reason - why we are inserting command to queue.
210 * Lock status: Assumed that lock is not held upon entry.
214 * Notes: We do this for one of two cases. Either the host is busy
215 * and it cannot accept any more commands for the time being,
216 * or the device returned QUEUE_FULL and can accept no more
218 * Notes: This could be called either from an interrupt context or a
219 * normal process context.
221 void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
223 __scsi_queue_insert(cmd, reason, true);
228 * scsi_execute - insert request and wait for the result
231 * @data_direction: data direction
232 * @buffer: data buffer
233 * @bufflen: len of buffer
234 * @sense: optional sense buffer
235 * @sshdr: optional decoded sense header
236 * @timeout: request timeout in seconds
237 * @retries: number of times to retry request
238 * @flags: flags for ->cmd_flags
239 * @rq_flags: flags for ->rq_flags
240 * @resid: optional residual length
242 * Returns the scsi_cmnd result field if a command was executed, or a negative
243 * Linux error code if we didn't get that far.
245 int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
246 int data_direction, void *buffer, unsigned bufflen,
247 unsigned char *sense, struct scsi_sense_hdr *sshdr,
248 int timeout, int retries, u64 flags, req_flags_t rq_flags,
252 struct scsi_request *rq;
253 int ret = DRIVER_ERROR << 24;
255 req = blk_get_request_flags(sdev->request_queue,
256 data_direction == DMA_TO_DEVICE ?
257 REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, BLK_MQ_REQ_PREEMPT);
262 if (bufflen && blk_rq_map_kern(sdev->request_queue, req,
263 buffer, bufflen, __GFP_RECLAIM))
266 rq->cmd_len = COMMAND_SIZE(cmd[0]);
267 memcpy(rq->cmd, cmd, rq->cmd_len);
268 rq->retries = retries;
269 req->timeout = timeout;
270 req->cmd_flags |= flags;
271 req->rq_flags |= rq_flags | RQF_QUIET;
274 * head injection *required* here otherwise quiesce won't work
276 blk_execute_rq(req->q, NULL, req, 1);
279 * Some devices (USB mass-storage in particular) may transfer
280 * garbage data together with a residue indicating that the data
281 * is invalid. Prevent the garbage from being misinterpreted
282 * and prevent security leaks by zeroing out the excess data.
284 if (unlikely(rq->resid_len > 0 && rq->resid_len <= bufflen))
285 memset(buffer + (bufflen - rq->resid_len), 0, rq->resid_len);
288 *resid = rq->resid_len;
289 if (sense && rq->sense_len)
290 memcpy(sense, rq->sense, SCSI_SENSE_BUFFERSIZE);
292 scsi_normalize_sense(rq->sense, rq->sense_len, sshdr);
295 blk_put_request(req);
299 EXPORT_SYMBOL(scsi_execute);
302 * Function: scsi_init_cmd_errh()
304 * Purpose: Initialize cmd fields related to error handling.
306 * Arguments: cmd - command that is ready to be queued.
308 * Notes: This function has the job of initializing a number of
309 * fields related to error handling. Typically this will
310 * be called once for each command, as required.
312 static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
314 cmd->serial_number = 0;
315 scsi_set_resid(cmd, 0);
316 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
317 if (cmd->cmd_len == 0)
318 cmd->cmd_len = scsi_command_size(cmd->cmnd);
322 * Decrement the host_busy counter and wake up the error handler if necessary.
323 * Avoid as follows that the error handler is not woken up if shost->host_busy
324 * == shost->host_failed: use call_rcu() in scsi_eh_scmd_add() in combination
325 * with an RCU read lock in this function to ensure that this function in its
326 * entirety either finishes before scsi_eh_scmd_add() increases the
327 * host_failed counter or that it notices the shost state change made by
328 * scsi_eh_scmd_add().
330 static void scsi_dec_host_busy(struct Scsi_Host *shost)
335 atomic_dec(&shost->host_busy);
336 if (unlikely(scsi_host_in_recovery(shost))) {
337 spin_lock_irqsave(shost->host_lock, flags);
338 if (shost->host_failed || shost->host_eh_scheduled)
339 scsi_eh_wakeup(shost);
340 spin_unlock_irqrestore(shost->host_lock, flags);
345 void scsi_device_unbusy(struct scsi_device *sdev)
347 struct Scsi_Host *shost = sdev->host;
348 struct scsi_target *starget = scsi_target(sdev);
350 scsi_dec_host_busy(shost);
352 if (starget->can_queue > 0)
353 atomic_dec(&starget->target_busy);
355 atomic_dec(&sdev->device_busy);
358 static void scsi_kick_queue(struct request_queue *q)
361 blk_mq_start_hw_queues(q);
367 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
368 * and call blk_run_queue for all the scsi_devices on the target -
369 * including current_sdev first.
371 * Called with *no* scsi locks held.
373 static void scsi_single_lun_run(struct scsi_device *current_sdev)
375 struct Scsi_Host *shost = current_sdev->host;
376 struct scsi_device *sdev, *tmp;
377 struct scsi_target *starget = scsi_target(current_sdev);
380 spin_lock_irqsave(shost->host_lock, flags);
381 starget->starget_sdev_user = NULL;
382 spin_unlock_irqrestore(shost->host_lock, flags);
385 * Call blk_run_queue for all LUNs on the target, starting with
386 * current_sdev. We race with others (to set starget_sdev_user),
387 * but in most cases, we will be first. Ideally, each LU on the
388 * target would get some limited time or requests on the target.
390 scsi_kick_queue(current_sdev->request_queue);
392 spin_lock_irqsave(shost->host_lock, flags);
393 if (starget->starget_sdev_user)
395 list_for_each_entry_safe(sdev, tmp, &starget->devices,
396 same_target_siblings) {
397 if (sdev == current_sdev)
399 if (scsi_device_get(sdev))
402 spin_unlock_irqrestore(shost->host_lock, flags);
403 scsi_kick_queue(sdev->request_queue);
404 spin_lock_irqsave(shost->host_lock, flags);
406 scsi_device_put(sdev);
409 spin_unlock_irqrestore(shost->host_lock, flags);
412 static inline bool scsi_device_is_busy(struct scsi_device *sdev)
414 if (atomic_read(&sdev->device_busy) >= sdev->queue_depth)
416 if (atomic_read(&sdev->device_blocked) > 0)
421 static inline bool scsi_target_is_busy(struct scsi_target *starget)
423 if (starget->can_queue > 0) {
424 if (atomic_read(&starget->target_busy) >= starget->can_queue)
426 if (atomic_read(&starget->target_blocked) > 0)
432 static inline bool scsi_host_is_busy(struct Scsi_Host *shost)
434 if (shost->can_queue > 0 &&
435 atomic_read(&shost->host_busy) >= shost->can_queue)
437 if (atomic_read(&shost->host_blocked) > 0)
439 if (shost->host_self_blocked)
444 static void scsi_starved_list_run(struct Scsi_Host *shost)
446 LIST_HEAD(starved_list);
447 struct scsi_device *sdev;
450 spin_lock_irqsave(shost->host_lock, flags);
451 list_splice_init(&shost->starved_list, &starved_list);
453 while (!list_empty(&starved_list)) {
454 struct request_queue *slq;
457 * As long as shost is accepting commands and we have
458 * starved queues, call blk_run_queue. scsi_request_fn
459 * drops the queue_lock and can add us back to the
462 * host_lock protects the starved_list and starved_entry.
463 * scsi_request_fn must get the host_lock before checking
464 * or modifying starved_list or starved_entry.
466 if (scsi_host_is_busy(shost))
469 sdev = list_entry(starved_list.next,
470 struct scsi_device, starved_entry);
471 list_del_init(&sdev->starved_entry);
472 if (scsi_target_is_busy(scsi_target(sdev))) {
473 list_move_tail(&sdev->starved_entry,
474 &shost->starved_list);
479 * Once we drop the host lock, a racing scsi_remove_device()
480 * call may remove the sdev from the starved list and destroy
481 * it and the queue. Mitigate by taking a reference to the
482 * queue and never touching the sdev again after we drop the
483 * host lock. Note: if __scsi_remove_device() invokes
484 * blk_cleanup_queue() before the queue is run from this
485 * function then blk_run_queue() will return immediately since
486 * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING.
488 slq = sdev->request_queue;
489 if (!blk_get_queue(slq))
491 spin_unlock_irqrestore(shost->host_lock, flags);
493 scsi_kick_queue(slq);
496 spin_lock_irqsave(shost->host_lock, flags);
498 /* put any unprocessed entries back */
499 list_splice(&starved_list, &shost->starved_list);
500 spin_unlock_irqrestore(shost->host_lock, flags);
504 * Function: scsi_run_queue()
506 * Purpose: Select a proper request queue to serve next
508 * Arguments: q - last request's queue
512 * Notes: The previous command was completely finished, start
513 * a new one if possible.
515 static void scsi_run_queue(struct request_queue *q)
517 struct scsi_device *sdev = q->queuedata;
519 if (scsi_target(sdev)->single_lun)
520 scsi_single_lun_run(sdev);
521 if (!list_empty(&sdev->host->starved_list))
522 scsi_starved_list_run(sdev->host);
525 blk_mq_run_hw_queues(q, false);
530 void scsi_requeue_run_queue(struct work_struct *work)
532 struct scsi_device *sdev;
533 struct request_queue *q;
535 sdev = container_of(work, struct scsi_device, requeue_work);
536 q = sdev->request_queue;
541 * Function: scsi_requeue_command()
543 * Purpose: Handle post-processing of completed commands.
545 * Arguments: q - queue to operate on
546 * cmd - command that may need to be requeued.
550 * Notes: After command completion, there may be blocks left
551 * over which weren't finished by the previous command
552 * this can be for a number of reasons - the main one is
553 * I/O errors in the middle of the request, in which case
554 * we need to request the blocks that come after the bad
556 * Notes: Upon return, cmd is a stale pointer.
558 static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd)
560 struct scsi_device *sdev = cmd->device;
561 struct request *req = cmd->request;
564 spin_lock_irqsave(q->queue_lock, flags);
565 blk_unprep_request(req);
567 scsi_put_command(cmd);
568 blk_requeue_request(q, req);
569 spin_unlock_irqrestore(q->queue_lock, flags);
573 put_device(&sdev->sdev_gendev);
576 void scsi_run_host_queues(struct Scsi_Host *shost)
578 struct scsi_device *sdev;
580 shost_for_each_device(sdev, shost)
581 scsi_run_queue(sdev->request_queue);
584 static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
586 if (!blk_rq_is_passthrough(cmd->request)) {
587 struct scsi_driver *drv = scsi_cmd_to_driver(cmd);
589 if (drv->uninit_command)
590 drv->uninit_command(cmd);
594 static void scsi_mq_free_sgtables(struct scsi_cmnd *cmd)
596 struct scsi_data_buffer *sdb;
598 if (cmd->sdb.table.nents)
599 sg_free_table_chained(&cmd->sdb.table, true);
600 if (cmd->request->next_rq) {
601 sdb = cmd->request->next_rq->special;
603 sg_free_table_chained(&sdb->table, true);
605 if (scsi_prot_sg_count(cmd))
606 sg_free_table_chained(&cmd->prot_sdb->table, true);
609 static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
611 scsi_mq_free_sgtables(cmd);
612 scsi_uninit_cmd(cmd);
613 scsi_del_cmd_from_list(cmd);
617 * Function: scsi_release_buffers()
619 * Purpose: Free resources allocate for a scsi_command.
621 * Arguments: cmd - command that we are bailing.
623 * Lock status: Assumed that no lock is held upon entry.
627 * Notes: In the event that an upper level driver rejects a
628 * command, we must release resources allocated during
629 * the __init_io() function. Primarily this would involve
630 * the scatter-gather table.
632 static void scsi_release_buffers(struct scsi_cmnd *cmd)
634 if (cmd->sdb.table.nents)
635 sg_free_table_chained(&cmd->sdb.table, false);
637 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
639 if (scsi_prot_sg_count(cmd))
640 sg_free_table_chained(&cmd->prot_sdb->table, false);
643 static void scsi_release_bidi_buffers(struct scsi_cmnd *cmd)
645 struct scsi_data_buffer *bidi_sdb = cmd->request->next_rq->special;
647 sg_free_table_chained(&bidi_sdb->table, false);
648 kmem_cache_free(scsi_sdb_cache, bidi_sdb);
649 cmd->request->next_rq->special = NULL;
652 static bool scsi_end_request(struct request *req, blk_status_t error,
653 unsigned int bytes, unsigned int bidi_bytes)
655 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
656 struct scsi_device *sdev = cmd->device;
657 struct request_queue *q = sdev->request_queue;
659 if (blk_update_request(req, error, bytes))
662 /* Bidi request must be completed as a whole */
663 if (unlikely(bidi_bytes) &&
664 blk_update_request(req->next_rq, error, bidi_bytes))
667 if (blk_queue_add_random(q))
668 add_disk_randomness(req->rq_disk);
670 if (!blk_rq_is_scsi(req)) {
671 WARN_ON_ONCE(!(cmd->flags & SCMD_INITIALIZED));
672 cmd->flags &= ~SCMD_INITIALIZED;
673 destroy_rcu_head(&cmd->rcu);
678 * In the MQ case the command gets freed by __blk_mq_end_request,
679 * so we have to do all cleanup that depends on it earlier.
681 * We also can't kick the queues from irq context, so we
682 * will have to defer it to a workqueue.
684 scsi_mq_uninit_cmd(cmd);
686 __blk_mq_end_request(req, error);
688 if (scsi_target(sdev)->single_lun ||
689 !list_empty(&sdev->host->starved_list))
690 kblockd_schedule_work(&sdev->requeue_work);
692 blk_mq_run_hw_queues(q, true);
697 scsi_release_bidi_buffers(cmd);
698 scsi_release_buffers(cmd);
699 scsi_put_command(cmd);
701 spin_lock_irqsave(q->queue_lock, flags);
702 blk_finish_request(req, error);
703 spin_unlock_irqrestore(q->queue_lock, flags);
708 put_device(&sdev->sdev_gendev);
713 * __scsi_error_from_host_byte - translate SCSI error code into errno
714 * @cmd: SCSI command (unused)
715 * @result: scsi error code
717 * Translate SCSI error code into block errors.
719 static blk_status_t __scsi_error_from_host_byte(struct scsi_cmnd *cmd,
722 switch (host_byte(result)) {
723 case DID_TRANSPORT_FAILFAST:
724 return BLK_STS_TRANSPORT;
725 case DID_TARGET_FAILURE:
726 set_host_byte(cmd, DID_OK);
727 return BLK_STS_TARGET;
728 case DID_NEXUS_FAILURE:
729 return BLK_STS_NEXUS;
730 case DID_ALLOC_FAILURE:
731 set_host_byte(cmd, DID_OK);
732 return BLK_STS_NOSPC;
733 case DID_MEDIUM_ERROR:
734 set_host_byte(cmd, DID_OK);
735 return BLK_STS_MEDIUM;
737 return BLK_STS_IOERR;
742 * Function: scsi_io_completion()
744 * Purpose: Completion processing for block device I/O requests.
746 * Arguments: cmd - command that is finished.
748 * Lock status: Assumed that no lock is held upon entry.
752 * Notes: We will finish off the specified number of sectors. If we
753 * are done, the command block will be released and the queue
754 * function will be goosed. If we are not done then we have to
755 * figure out what to do next:
757 * a) We can call scsi_requeue_command(). The request
758 * will be unprepared and put back on the queue. Then
759 * a new command will be created for it. This should
760 * be used if we made forward progress, or if we want
761 * to switch from READ(10) to READ(6) for example.
763 * b) We can call __scsi_queue_insert(). The request will
764 * be put back on the queue and retried using the same
765 * command as before, possibly after a delay.
767 * c) We can call scsi_end_request() with -EIO to fail
768 * the remainder of the request.
770 void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
772 int result = cmd->result;
773 struct request_queue *q = cmd->device->request_queue;
774 struct request *req = cmd->request;
775 blk_status_t error = BLK_STS_OK;
776 struct scsi_sense_hdr sshdr;
777 bool sense_valid = false;
778 int sense_deferred = 0, level = 0;
779 enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,
780 ACTION_DELAYED_RETRY} action;
781 unsigned long wait_for = (cmd->allowed + 1) * req->timeout;
784 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
786 sense_deferred = scsi_sense_is_deferred(&sshdr);
789 if (blk_rq_is_passthrough(req)) {
793 * SG_IO wants current and deferred errors
795 scsi_req(req)->sense_len =
796 min(8 + cmd->sense_buffer[7],
797 SCSI_SENSE_BUFFERSIZE);
800 error = __scsi_error_from_host_byte(cmd, result);
803 * __scsi_error_from_host_byte may have reset the host_byte
805 scsi_req(req)->result = cmd->result;
806 scsi_req(req)->resid_len = scsi_get_resid(cmd);
808 if (scsi_bidi_cmnd(cmd)) {
810 * Bidi commands Must be complete as a whole,
811 * both sides at once.
813 scsi_req(req->next_rq)->resid_len = scsi_in(cmd)->resid;
814 if (scsi_end_request(req, BLK_STS_OK, blk_rq_bytes(req),
815 blk_rq_bytes(req->next_rq)))
819 } else if (blk_rq_bytes(req) == 0 && result && !sense_deferred) {
821 * Flush commands do not transfers any data, and thus cannot use
822 * good_bytes != blk_rq_bytes(req) as the signal for an error.
823 * This sets the error explicitly for the problem case.
825 error = __scsi_error_from_host_byte(cmd, result);
828 /* no bidi support for !blk_rq_is_passthrough yet */
829 BUG_ON(blk_bidi_rq(req));
832 * Next deal with any sectors which we were able to correctly
835 SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd,
836 "%u sectors total, %d bytes done.\n",
837 blk_rq_sectors(req), good_bytes));
840 * Recovered errors need reporting, but they're always treated as
841 * success, so fiddle the result code here. For passthrough requests
842 * we already took a copy of the original into sreq->result which
843 * is what gets returned to the user
845 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
846 /* if ATA PASS-THROUGH INFORMATION AVAILABLE skip
847 * print since caller wants ATA registers. Only occurs on
848 * SCSI ATA PASS_THROUGH commands when CK_COND=1
850 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
852 else if (!(req->rq_flags & RQF_QUIET))
853 scsi_print_sense(cmd);
855 /* for passthrough error may be set */
860 * special case: failed zero length commands always need to
861 * drop down into the retry code. Otherwise, if we finished
862 * all bytes in the request we are done now.
864 if (!(blk_rq_bytes(req) == 0 && error) &&
865 !scsi_end_request(req, error, good_bytes, 0))
869 * Kill remainder if no retrys.
871 if (error && scsi_noretry_cmd(cmd)) {
872 if (scsi_end_request(req, error, blk_rq_bytes(req), 0))
878 * If there had been no error, but we have leftover bytes in the
879 * requeues just queue the command up again.
884 error = __scsi_error_from_host_byte(cmd, result);
886 if (host_byte(result) == DID_RESET) {
887 /* Third party bus reset or reset for error recovery
888 * reasons. Just retry the command and see what
891 action = ACTION_RETRY;
892 } else if (sense_valid && !sense_deferred) {
893 switch (sshdr.sense_key) {
895 if (cmd->device->removable) {
896 /* Detected disc change. Set a bit
897 * and quietly refuse further access.
899 cmd->device->changed = 1;
900 action = ACTION_FAIL;
902 /* Must have been a power glitch, or a
903 * bus reset. Could not have been a
904 * media change, so we just retry the
905 * command and see what happens.
907 action = ACTION_RETRY;
910 case ILLEGAL_REQUEST:
911 /* If we had an ILLEGAL REQUEST returned, then
912 * we may have performed an unsupported
913 * command. The only thing this should be
914 * would be a ten byte read where only a six
915 * byte read was supported. Also, on a system
916 * where READ CAPACITY failed, we may have
917 * read past the end of the disk.
919 if ((cmd->device->use_10_for_rw &&
920 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
921 (cmd->cmnd[0] == READ_10 ||
922 cmd->cmnd[0] == WRITE_10)) {
923 /* This will issue a new 6-byte command. */
924 cmd->device->use_10_for_rw = 0;
925 action = ACTION_REPREP;
926 } else if (sshdr.asc == 0x10) /* DIX */ {
927 action = ACTION_FAIL;
928 error = BLK_STS_PROTECTION;
929 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
930 } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
931 action = ACTION_FAIL;
932 error = BLK_STS_TARGET;
934 action = ACTION_FAIL;
936 case ABORTED_COMMAND:
937 action = ACTION_FAIL;
938 if (sshdr.asc == 0x10) /* DIF */
939 error = BLK_STS_PROTECTION;
942 /* If the device is in the process of becoming
943 * ready, or has a temporary blockage, retry.
945 if (sshdr.asc == 0x04) {
946 switch (sshdr.ascq) {
947 case 0x01: /* becoming ready */
948 case 0x04: /* format in progress */
949 case 0x05: /* rebuild in progress */
950 case 0x06: /* recalculation in progress */
951 case 0x07: /* operation in progress */
952 case 0x08: /* Long write in progress */
953 case 0x09: /* self test in progress */
954 case 0x14: /* space allocation in progress */
955 action = ACTION_DELAYED_RETRY;
958 action = ACTION_FAIL;
962 action = ACTION_FAIL;
964 case VOLUME_OVERFLOW:
965 /* See SSC3rXX or current. */
966 action = ACTION_FAIL;
969 action = ACTION_FAIL;
973 action = ACTION_FAIL;
975 if (action != ACTION_FAIL &&
976 time_before(cmd->jiffies_at_alloc + wait_for, jiffies))
977 action = ACTION_FAIL;
981 /* Give up and fail the remainder of the request */
982 if (!(req->rq_flags & RQF_QUIET)) {
983 static DEFINE_RATELIMIT_STATE(_rs,
984 DEFAULT_RATELIMIT_INTERVAL,
985 DEFAULT_RATELIMIT_BURST);
987 if (unlikely(scsi_logging_level))
988 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
989 SCSI_LOG_MLCOMPLETE_BITS);
992 * if logging is enabled the failure will be printed
993 * in scsi_log_completion(), so avoid duplicate messages
995 if (!level && __ratelimit(&_rs)) {
996 scsi_print_result(cmd, NULL, FAILED);
997 if (driver_byte(result) & DRIVER_SENSE)
998 scsi_print_sense(cmd);
999 scsi_print_command(cmd);
1002 if (!scsi_end_request(req, error, blk_rq_err_bytes(req), 0))
1007 /* Unprep the request and put it back at the head of the queue.
1008 * A new command will be prepared and issued.
1011 scsi_mq_requeue_cmd(cmd);
1013 scsi_release_buffers(cmd);
1014 scsi_requeue_command(q, cmd);
1018 /* Retry the same command immediately */
1019 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, false);
1021 case ACTION_DELAYED_RETRY:
1022 /* Retry the same command after a delay */
1023 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, false);
1028 static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb)
1033 * If sg table allocation fails, requeue request later.
1035 if (unlikely(sg_alloc_table_chained(&sdb->table,
1036 blk_rq_nr_phys_segments(req), sdb->table.sgl)))
1037 return BLKPREP_DEFER;
1040 * Next, walk the list, and fill in the addresses and sizes of
1043 count = blk_rq_map_sg(req->q, req, sdb->table.sgl);
1044 BUG_ON(count > sdb->table.nents);
1045 sdb->table.nents = count;
1046 sdb->length = blk_rq_payload_bytes(req);
1051 * Function: scsi_init_io()
1053 * Purpose: SCSI I/O initialize function.
1055 * Arguments: cmd - Command descriptor we wish to initialize
1057 * Returns: 0 on success
1058 * BLKPREP_DEFER if the failure is retryable
1059 * BLKPREP_KILL if the failure is fatal
1061 int scsi_init_io(struct scsi_cmnd *cmd)
1063 struct scsi_device *sdev = cmd->device;
1064 struct request *rq = cmd->request;
1065 bool is_mq = (rq->mq_ctx != NULL);
1066 int error = BLKPREP_KILL;
1068 if (WARN_ON_ONCE(!blk_rq_nr_phys_segments(rq)))
1071 error = scsi_init_sgtable(rq, &cmd->sdb);
1075 if (blk_bidi_rq(rq)) {
1076 if (!rq->q->mq_ops) {
1077 struct scsi_data_buffer *bidi_sdb =
1078 kmem_cache_zalloc(scsi_sdb_cache, GFP_ATOMIC);
1080 error = BLKPREP_DEFER;
1084 rq->next_rq->special = bidi_sdb;
1087 error = scsi_init_sgtable(rq->next_rq, rq->next_rq->special);
1092 if (blk_integrity_rq(rq)) {
1093 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1096 if (prot_sdb == NULL) {
1098 * This can happen if someone (e.g. multipath)
1099 * queues a command to a device on an adapter
1100 * that does not support DIX.
1103 error = BLKPREP_KILL;
1107 ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
1109 if (sg_alloc_table_chained(&prot_sdb->table, ivecs,
1110 prot_sdb->table.sgl)) {
1111 error = BLKPREP_DEFER;
1115 count = blk_rq_map_integrity_sg(rq->q, rq->bio,
1116 prot_sdb->table.sgl);
1117 BUG_ON(unlikely(count > ivecs));
1118 BUG_ON(unlikely(count > queue_max_integrity_segments(rq->q)));
1120 cmd->prot_sdb = prot_sdb;
1121 cmd->prot_sdb->table.nents = count;
1127 scsi_mq_free_sgtables(cmd);
1129 scsi_release_buffers(cmd);
1130 cmd->request->special = NULL;
1131 scsi_put_command(cmd);
1132 put_device(&sdev->sdev_gendev);
1136 EXPORT_SYMBOL(scsi_init_io);
1139 * scsi_initialize_rq - initialize struct scsi_cmnd partially
1140 * @rq: Request associated with the SCSI command to be initialized.
1142 * This function initializes the members of struct scsi_cmnd that must be
1143 * initialized before request processing starts and that won't be
1144 * reinitialized if a SCSI command is requeued.
1146 * Called from inside blk_get_request() for pass-through requests and from
1147 * inside scsi_init_command() for filesystem requests.
1149 static void scsi_initialize_rq(struct request *rq)
1151 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1153 scsi_req_init(&cmd->req);
1154 init_rcu_head(&cmd->rcu);
1155 cmd->jiffies_at_alloc = jiffies;
1159 /* Add a command to the list used by the aacraid and dpt_i2o drivers */
1160 void scsi_add_cmd_to_list(struct scsi_cmnd *cmd)
1162 struct scsi_device *sdev = cmd->device;
1163 struct Scsi_Host *shost = sdev->host;
1164 unsigned long flags;
1166 if (shost->use_cmd_list) {
1167 spin_lock_irqsave(&sdev->list_lock, flags);
1168 list_add_tail(&cmd->list, &sdev->cmd_list);
1169 spin_unlock_irqrestore(&sdev->list_lock, flags);
1173 /* Remove a command from the list used by the aacraid and dpt_i2o drivers */
1174 void scsi_del_cmd_from_list(struct scsi_cmnd *cmd)
1176 struct scsi_device *sdev = cmd->device;
1177 struct Scsi_Host *shost = sdev->host;
1178 unsigned long flags;
1180 if (shost->use_cmd_list) {
1181 spin_lock_irqsave(&sdev->list_lock, flags);
1182 BUG_ON(list_empty(&cmd->list));
1183 list_del_init(&cmd->list);
1184 spin_unlock_irqrestore(&sdev->list_lock, flags);
1188 /* Called after a request has been started. */
1189 void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd)
1191 void *buf = cmd->sense_buffer;
1192 void *prot = cmd->prot_sdb;
1193 struct request *rq = blk_mq_rq_from_pdu(cmd);
1194 unsigned int flags = cmd->flags & SCMD_PRESERVED_FLAGS;
1195 unsigned long jiffies_at_alloc;
1198 if (!blk_rq_is_scsi(rq) && !(flags & SCMD_INITIALIZED)) {
1199 flags |= SCMD_INITIALIZED;
1200 scsi_initialize_rq(rq);
1203 jiffies_at_alloc = cmd->jiffies_at_alloc;
1204 retries = cmd->retries;
1205 /* zero out the cmd, except for the embedded scsi_request */
1206 memset((char *)cmd + sizeof(cmd->req), 0,
1207 sizeof(*cmd) - sizeof(cmd->req) + dev->host->hostt->cmd_size);
1210 cmd->sense_buffer = buf;
1211 cmd->prot_sdb = prot;
1213 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
1214 cmd->jiffies_at_alloc = jiffies_at_alloc;
1215 cmd->retries = retries;
1217 scsi_add_cmd_to_list(cmd);
1220 static int scsi_setup_scsi_cmnd(struct scsi_device *sdev, struct request *req)
1222 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1225 * Passthrough requests may transfer data, in which case they must
1226 * a bio attached to them. Or they might contain a SCSI command
1227 * that does not transfer data, in which case they may optionally
1228 * submit a request without an attached bio.
1231 int ret = scsi_init_io(cmd);
1235 BUG_ON(blk_rq_bytes(req));
1237 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1240 cmd->cmd_len = scsi_req(req)->cmd_len;
1241 cmd->cmnd = scsi_req(req)->cmd;
1242 cmd->transfersize = blk_rq_bytes(req);
1243 cmd->allowed = scsi_req(req)->retries;
1248 * Setup a normal block command. These are simple request from filesystems
1249 * that still need to be translated to SCSI CDBs from the ULD.
1251 static int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
1253 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1255 if (unlikely(sdev->handler && sdev->handler->prep_fn)) {
1256 int ret = sdev->handler->prep_fn(sdev, req);
1257 if (ret != BLKPREP_OK)
1261 cmd->cmnd = scsi_req(req)->cmd = scsi_req(req)->__cmd;
1262 memset(cmd->cmnd, 0, BLK_MAX_CDB);
1263 return scsi_cmd_to_driver(cmd)->init_command(cmd);
1266 static int scsi_setup_cmnd(struct scsi_device *sdev, struct request *req)
1268 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1270 if (!blk_rq_bytes(req))
1271 cmd->sc_data_direction = DMA_NONE;
1272 else if (rq_data_dir(req) == WRITE)
1273 cmd->sc_data_direction = DMA_TO_DEVICE;
1275 cmd->sc_data_direction = DMA_FROM_DEVICE;
1277 if (blk_rq_is_scsi(req))
1278 return scsi_setup_scsi_cmnd(sdev, req);
1280 return scsi_setup_fs_cmnd(sdev, req);
1284 scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
1286 int ret = BLKPREP_OK;
1289 * If the device is not in running state we will reject some
1292 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
1293 switch (sdev->sdev_state) {
1295 case SDEV_TRANSPORT_OFFLINE:
1297 * If the device is offline we refuse to process any
1298 * commands. The device must be brought online
1299 * before trying any recovery commands.
1301 sdev_printk(KERN_ERR, sdev,
1302 "rejecting I/O to offline device\n");
1307 * If the device is fully deleted, we refuse to
1308 * process any commands as well.
1310 sdev_printk(KERN_ERR, sdev,
1311 "rejecting I/O to dead device\n");
1315 case SDEV_CREATED_BLOCK:
1316 ret = BLKPREP_DEFER;
1320 * If the devices is blocked we defer normal commands.
1322 if (req && !(req->rq_flags & RQF_PREEMPT))
1323 ret = BLKPREP_DEFER;
1327 * For any other not fully online state we only allow
1328 * special commands. In particular any user initiated
1329 * command is not allowed.
1331 if (req && !(req->rq_flags & RQF_PREEMPT))
1340 scsi_prep_return(struct request_queue *q, struct request *req, int ret)
1342 struct scsi_device *sdev = q->queuedata;
1346 case BLKPREP_INVALID:
1347 scsi_req(req)->result = DID_NO_CONNECT << 16;
1348 /* release the command and kill it */
1350 struct scsi_cmnd *cmd = req->special;
1351 scsi_release_buffers(cmd);
1352 scsi_put_command(cmd);
1353 put_device(&sdev->sdev_gendev);
1354 req->special = NULL;
1359 * If we defer, the blk_peek_request() returns NULL, but the
1360 * queue must be restarted, so we schedule a callback to happen
1363 if (atomic_read(&sdev->device_busy) == 0)
1364 blk_delay_queue(q, SCSI_QUEUE_DELAY);
1367 req->rq_flags |= RQF_DONTPREP;
1373 static int scsi_prep_fn(struct request_queue *q, struct request *req)
1375 struct scsi_device *sdev = q->queuedata;
1376 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1379 ret = scsi_prep_state_check(sdev, req);
1380 if (ret != BLKPREP_OK)
1383 if (!req->special) {
1384 /* Bail if we can't get a reference to the device */
1385 if (unlikely(!get_device(&sdev->sdev_gendev))) {
1386 ret = BLKPREP_DEFER;
1390 scsi_init_command(sdev, cmd);
1394 cmd->tag = req->tag;
1396 cmd->prot_op = SCSI_PROT_NORMAL;
1398 ret = scsi_setup_cmnd(sdev, req);
1400 return scsi_prep_return(q, req, ret);
1403 static void scsi_unprep_fn(struct request_queue *q, struct request *req)
1405 scsi_uninit_cmd(blk_mq_rq_to_pdu(req));
1409 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1412 * Called with the queue_lock held.
1414 static inline int scsi_dev_queue_ready(struct request_queue *q,
1415 struct scsi_device *sdev)
1419 busy = atomic_inc_return(&sdev->device_busy) - 1;
1420 if (atomic_read(&sdev->device_blocked)) {
1425 * unblock after device_blocked iterates to zero
1427 if (atomic_dec_return(&sdev->device_blocked) > 0) {
1429 * For the MQ case we take care of this in the caller.
1432 blk_delay_queue(q, SCSI_QUEUE_DELAY);
1435 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev,
1436 "unblocking device at zero depth\n"));
1439 if (busy >= sdev->queue_depth)
1444 atomic_dec(&sdev->device_busy);
1449 * scsi_target_queue_ready: checks if there we can send commands to target
1450 * @sdev: scsi device on starget to check.
1452 static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1453 struct scsi_device *sdev)
1455 struct scsi_target *starget = scsi_target(sdev);
1458 if (starget->single_lun) {
1459 spin_lock_irq(shost->host_lock);
1460 if (starget->starget_sdev_user &&
1461 starget->starget_sdev_user != sdev) {
1462 spin_unlock_irq(shost->host_lock);
1465 starget->starget_sdev_user = sdev;
1466 spin_unlock_irq(shost->host_lock);
1469 if (starget->can_queue <= 0)
1472 busy = atomic_inc_return(&starget->target_busy) - 1;
1473 if (atomic_read(&starget->target_blocked) > 0) {
1478 * unblock after target_blocked iterates to zero
1480 if (atomic_dec_return(&starget->target_blocked) > 0)
1483 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1484 "unblocking target at zero depth\n"));
1487 if (busy >= starget->can_queue)
1493 spin_lock_irq(shost->host_lock);
1494 list_move_tail(&sdev->starved_entry, &shost->starved_list);
1495 spin_unlock_irq(shost->host_lock);
1497 if (starget->can_queue > 0)
1498 atomic_dec(&starget->target_busy);
1503 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1504 * return 0. We must end up running the queue again whenever 0 is
1505 * returned, else IO can hang.
1507 static inline int scsi_host_queue_ready(struct request_queue *q,
1508 struct Scsi_Host *shost,
1509 struct scsi_device *sdev)
1513 if (scsi_host_in_recovery(shost))
1516 busy = atomic_inc_return(&shost->host_busy) - 1;
1517 if (atomic_read(&shost->host_blocked) > 0) {
1522 * unblock after host_blocked iterates to zero
1524 if (atomic_dec_return(&shost->host_blocked) > 0)
1528 shost_printk(KERN_INFO, shost,
1529 "unblocking host at zero depth\n"));
1532 if (shost->can_queue > 0 && busy >= shost->can_queue)
1534 if (shost->host_self_blocked)
1537 /* We're OK to process the command, so we can't be starved */
1538 if (!list_empty(&sdev->starved_entry)) {
1539 spin_lock_irq(shost->host_lock);
1540 if (!list_empty(&sdev->starved_entry))
1541 list_del_init(&sdev->starved_entry);
1542 spin_unlock_irq(shost->host_lock);
1548 spin_lock_irq(shost->host_lock);
1549 if (list_empty(&sdev->starved_entry))
1550 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1551 spin_unlock_irq(shost->host_lock);
1553 scsi_dec_host_busy(shost);
1558 * Busy state exporting function for request stacking drivers.
1560 * For efficiency, no lock is taken to check the busy state of
1561 * shost/starget/sdev, since the returned value is not guaranteed and
1562 * may be changed after request stacking drivers call the function,
1563 * regardless of taking lock or not.
1565 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1566 * needs to return 'not busy'. Otherwise, request stacking drivers
1567 * may hold requests forever.
1569 static int scsi_lld_busy(struct request_queue *q)
1571 struct scsi_device *sdev = q->queuedata;
1572 struct Scsi_Host *shost;
1574 if (blk_queue_dying(q))
1580 * Ignore host/starget busy state.
1581 * Since block layer does not have a concept of fairness across
1582 * multiple queues, congestion of host/starget needs to be handled
1585 if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
1592 * Kill a request for a dead device
1594 static void scsi_kill_request(struct request *req, struct request_queue *q)
1596 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1597 struct scsi_device *sdev;
1598 struct scsi_target *starget;
1599 struct Scsi_Host *shost;
1601 blk_start_request(req);
1603 scmd_printk(KERN_INFO, cmd, "killing request\n");
1606 starget = scsi_target(sdev);
1608 scsi_init_cmd_errh(cmd);
1609 cmd->result = DID_NO_CONNECT << 16;
1610 atomic_inc(&cmd->device->iorequest_cnt);
1613 * SCSI request completion path will do scsi_device_unbusy(),
1614 * bump busy counts. To bump the counters, we need to dance
1615 * with the locks as normal issue path does.
1617 atomic_inc(&sdev->device_busy);
1618 atomic_inc(&shost->host_busy);
1619 if (starget->can_queue > 0)
1620 atomic_inc(&starget->target_busy);
1622 blk_complete_request(req);
1625 static void scsi_softirq_done(struct request *rq)
1627 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1628 unsigned long wait_for = (cmd->allowed + 1) * rq->timeout;
1631 INIT_LIST_HEAD(&cmd->eh_entry);
1633 atomic_inc(&cmd->device->iodone_cnt);
1635 atomic_inc(&cmd->device->ioerr_cnt);
1637 disposition = scsi_decide_disposition(cmd);
1638 if (disposition != SUCCESS &&
1639 time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
1640 sdev_printk(KERN_ERR, cmd->device,
1641 "timing out command, waited %lus\n",
1643 disposition = SUCCESS;
1646 scsi_log_completion(cmd, disposition);
1648 switch (disposition) {
1650 scsi_finish_command(cmd);
1653 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
1655 case ADD_TO_MLQUEUE:
1656 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1659 scsi_eh_scmd_add(cmd);
1665 * scsi_dispatch_command - Dispatch a command to the low-level driver.
1666 * @cmd: command block we are dispatching.
1668 * Return: nonzero return request was rejected and device's queue needs to be
1671 static int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
1673 struct Scsi_Host *host = cmd->device->host;
1676 atomic_inc(&cmd->device->iorequest_cnt);
1678 /* check if the device is still usable */
1679 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
1680 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
1681 * returns an immediate error upwards, and signals
1682 * that the device is no longer present */
1683 cmd->result = DID_NO_CONNECT << 16;
1687 /* Check to see if the scsi lld made this device blocked. */
1688 if (unlikely(scsi_device_blocked(cmd->device))) {
1690 * in blocked state, the command is just put back on
1691 * the device queue. The suspend state has already
1692 * blocked the queue so future requests should not
1693 * occur until the device transitions out of the
1696 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1697 "queuecommand : device blocked\n"));
1698 return SCSI_MLQUEUE_DEVICE_BUSY;
1701 /* Store the LUN value in cmnd, if needed. */
1702 if (cmd->device->lun_in_cdb)
1703 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
1704 (cmd->device->lun << 5 & 0xe0);
1709 * Before we queue this command, check if the command
1710 * length exceeds what the host adapter can handle.
1712 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
1713 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1714 "queuecommand : command too long. "
1715 "cdb_size=%d host->max_cmd_len=%d\n",
1716 cmd->cmd_len, cmd->device->host->max_cmd_len));
1717 cmd->result = (DID_ABORT << 16);
1721 if (unlikely(host->shost_state == SHOST_DEL)) {
1722 cmd->result = (DID_NO_CONNECT << 16);
1727 trace_scsi_dispatch_cmd_start(cmd);
1728 rtn = host->hostt->queuecommand(host, cmd);
1730 trace_scsi_dispatch_cmd_error(cmd, rtn);
1731 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
1732 rtn != SCSI_MLQUEUE_TARGET_BUSY)
1733 rtn = SCSI_MLQUEUE_HOST_BUSY;
1735 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1736 "queuecommand : request rejected\n"));
1741 cmd->scsi_done(cmd);
1746 * scsi_done - Invoke completion on finished SCSI command.
1747 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
1748 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
1750 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
1751 * which regains ownership of the SCSI command (de facto) from a LLDD, and
1752 * calls blk_complete_request() for further processing.
1754 * This function is interrupt context safe.
1756 static void scsi_done(struct scsi_cmnd *cmd)
1758 trace_scsi_dispatch_cmd_done(cmd);
1759 blk_complete_request(cmd->request);
1763 * Function: scsi_request_fn()
1765 * Purpose: Main strategy routine for SCSI.
1767 * Arguments: q - Pointer to actual queue.
1771 * Lock status: request queue lock assumed to be held when called.
1773 * Note: See sd_zbc.c sd_zbc_write_lock_zone() for write order
1774 * protection for ZBC disks.
1776 static void scsi_request_fn(struct request_queue *q)
1777 __releases(q->queue_lock)
1778 __acquires(q->queue_lock)
1780 struct scsi_device *sdev = q->queuedata;
1781 struct Scsi_Host *shost;
1782 struct scsi_cmnd *cmd;
1783 struct request *req;
1786 * To start with, we keep looping until the queue is empty, or until
1787 * the host is no longer able to accept any more requests.
1793 * get next queueable request. We do this early to make sure
1794 * that the request is fully prepared even if we cannot
1797 req = blk_peek_request(q);
1801 if (unlikely(!scsi_device_online(sdev))) {
1802 sdev_printk(KERN_ERR, sdev,
1803 "rejecting I/O to offline device\n");
1804 scsi_kill_request(req, q);
1808 if (!scsi_dev_queue_ready(q, sdev))
1812 * Remove the request from the request list.
1814 if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req)))
1815 blk_start_request(req);
1817 spin_unlock_irq(q->queue_lock);
1818 cmd = blk_mq_rq_to_pdu(req);
1819 if (cmd != req->special) {
1820 printk(KERN_CRIT "impossible request in %s.\n"
1821 "please mail a stack trace to "
1822 "linux-scsi@vger.kernel.org\n",
1824 blk_dump_rq_flags(req, "foo");
1829 * We hit this when the driver is using a host wide
1830 * tag map. For device level tag maps the queue_depth check
1831 * in the device ready fn would prevent us from trying
1832 * to allocate a tag. Since the map is a shared host resource
1833 * we add the dev to the starved list so it eventually gets
1834 * a run when a tag is freed.
1836 if (blk_queue_tagged(q) && !(req->rq_flags & RQF_QUEUED)) {
1837 spin_lock_irq(shost->host_lock);
1838 if (list_empty(&sdev->starved_entry))
1839 list_add_tail(&sdev->starved_entry,
1840 &shost->starved_list);
1841 spin_unlock_irq(shost->host_lock);
1845 if (!scsi_target_queue_ready(shost, sdev))
1848 if (!scsi_host_queue_ready(q, shost, sdev))
1849 goto host_not_ready;
1851 if (sdev->simple_tags)
1852 cmd->flags |= SCMD_TAGGED;
1854 cmd->flags &= ~SCMD_TAGGED;
1857 * Finally, initialize any error handling parameters, and set up
1858 * the timers for timeouts.
1860 scsi_init_cmd_errh(cmd);
1863 * Dispatch the command to the low-level driver.
1865 cmd->scsi_done = scsi_done;
1866 rtn = scsi_dispatch_cmd(cmd);
1868 scsi_queue_insert(cmd, rtn);
1869 spin_lock_irq(q->queue_lock);
1872 spin_lock_irq(q->queue_lock);
1878 if (scsi_target(sdev)->can_queue > 0)
1879 atomic_dec(&scsi_target(sdev)->target_busy);
1882 * lock q, handle tag, requeue req, and decrement device_busy. We
1883 * must return with queue_lock held.
1885 * Decrementing device_busy without checking it is OK, as all such
1886 * cases (host limits or settings) should run the queue at some
1889 spin_lock_irq(q->queue_lock);
1890 blk_requeue_request(q, req);
1891 atomic_dec(&sdev->device_busy);
1893 if (!atomic_read(&sdev->device_busy) && !scsi_device_blocked(sdev))
1894 blk_delay_queue(q, SCSI_QUEUE_DELAY);
1897 static inline blk_status_t prep_to_mq(int ret)
1903 return BLK_STS_RESOURCE;
1905 return BLK_STS_IOERR;
1909 /* Size in bytes of the sg-list stored in the scsi-mq command-private data. */
1910 static unsigned int scsi_mq_sgl_size(struct Scsi_Host *shost)
1912 return min_t(unsigned int, shost->sg_tablesize, SG_CHUNK_SIZE) *
1913 sizeof(struct scatterlist);
1916 static int scsi_mq_prep_fn(struct request *req)
1918 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1919 struct scsi_device *sdev = req->q->queuedata;
1920 struct Scsi_Host *shost = sdev->host;
1921 struct scatterlist *sg;
1923 scsi_init_command(sdev, cmd);
1929 cmd->tag = req->tag;
1930 cmd->prot_op = SCSI_PROT_NORMAL;
1932 sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
1933 cmd->sdb.table.sgl = sg;
1935 if (scsi_host_get_prot(shost)) {
1936 memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer));
1938 cmd->prot_sdb->table.sgl =
1939 (struct scatterlist *)(cmd->prot_sdb + 1);
1942 if (blk_bidi_rq(req)) {
1943 struct request *next_rq = req->next_rq;
1944 struct scsi_data_buffer *bidi_sdb = blk_mq_rq_to_pdu(next_rq);
1946 memset(bidi_sdb, 0, sizeof(struct scsi_data_buffer));
1947 bidi_sdb->table.sgl =
1948 (struct scatterlist *)(bidi_sdb + 1);
1950 next_rq->special = bidi_sdb;
1953 blk_mq_start_request(req);
1955 return scsi_setup_cmnd(sdev, req);
1958 static void scsi_mq_done(struct scsi_cmnd *cmd)
1960 trace_scsi_dispatch_cmd_done(cmd);
1961 blk_mq_complete_request(cmd->request);
1964 static void scsi_mq_put_budget(struct blk_mq_hw_ctx *hctx)
1966 struct request_queue *q = hctx->queue;
1967 struct scsi_device *sdev = q->queuedata;
1969 atomic_dec(&sdev->device_busy);
1970 put_device(&sdev->sdev_gendev);
1973 static bool scsi_mq_get_budget(struct blk_mq_hw_ctx *hctx)
1975 struct request_queue *q = hctx->queue;
1976 struct scsi_device *sdev = q->queuedata;
1978 if (!get_device(&sdev->sdev_gendev))
1980 if (!scsi_dev_queue_ready(q, sdev))
1981 goto out_put_device;
1986 put_device(&sdev->sdev_gendev);
1991 static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
1992 const struct blk_mq_queue_data *bd)
1994 struct request *req = bd->rq;
1995 struct request_queue *q = req->q;
1996 struct scsi_device *sdev = q->queuedata;
1997 struct Scsi_Host *shost = sdev->host;
1998 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
2002 ret = prep_to_mq(scsi_prep_state_check(sdev, req));
2003 if (ret != BLK_STS_OK)
2004 goto out_put_budget;
2006 ret = BLK_STS_RESOURCE;
2007 if (!scsi_target_queue_ready(shost, sdev))
2008 goto out_put_budget;
2009 if (!scsi_host_queue_ready(q, shost, sdev))
2010 goto out_dec_target_busy;
2012 if (!(req->rq_flags & RQF_DONTPREP)) {
2013 ret = prep_to_mq(scsi_mq_prep_fn(req));
2014 if (ret != BLK_STS_OK)
2015 goto out_dec_host_busy;
2016 req->rq_flags |= RQF_DONTPREP;
2018 blk_mq_start_request(req);
2021 if (sdev->simple_tags)
2022 cmd->flags |= SCMD_TAGGED;
2024 cmd->flags &= ~SCMD_TAGGED;
2026 scsi_init_cmd_errh(cmd);
2027 cmd->scsi_done = scsi_mq_done;
2029 reason = scsi_dispatch_cmd(cmd);
2031 scsi_set_blocked(cmd, reason);
2032 ret = BLK_STS_RESOURCE;
2033 goto out_dec_host_busy;
2039 scsi_dec_host_busy(shost);
2040 out_dec_target_busy:
2041 if (scsi_target(sdev)->can_queue > 0)
2042 atomic_dec(&scsi_target(sdev)->target_busy);
2044 scsi_mq_put_budget(hctx);
2048 case BLK_STS_RESOURCE:
2049 if (atomic_read(&sdev->device_busy) == 0 &&
2050 !scsi_device_blocked(sdev))
2051 blk_mq_delay_run_hw_queue(hctx, SCSI_QUEUE_DELAY);
2055 * Make sure to release all allocated ressources when
2056 * we hit an error, as we will never see this command
2059 if (req->rq_flags & RQF_DONTPREP)
2060 scsi_mq_uninit_cmd(cmd);
2066 static enum blk_eh_timer_return scsi_timeout(struct request *req,
2070 return BLK_EH_RESET_TIMER;
2071 return scsi_times_out(req);
2074 static int scsi_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
2075 unsigned int hctx_idx, unsigned int numa_node)
2077 struct Scsi_Host *shost = set->driver_data;
2078 const bool unchecked_isa_dma = shost->unchecked_isa_dma;
2079 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
2080 struct scatterlist *sg;
2082 if (unchecked_isa_dma)
2083 cmd->flags |= SCMD_UNCHECKED_ISA_DMA;
2084 cmd->sense_buffer = scsi_alloc_sense_buffer(unchecked_isa_dma,
2085 GFP_KERNEL, numa_node);
2086 if (!cmd->sense_buffer)
2088 cmd->req.sense = cmd->sense_buffer;
2090 if (scsi_host_get_prot(shost)) {
2091 sg = (void *)cmd + sizeof(struct scsi_cmnd) +
2092 shost->hostt->cmd_size;
2093 cmd->prot_sdb = (void *)sg + scsi_mq_sgl_size(shost);
2099 static void scsi_mq_exit_request(struct blk_mq_tag_set *set, struct request *rq,
2100 unsigned int hctx_idx)
2102 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
2104 scsi_free_sense_buffer(cmd->flags & SCMD_UNCHECKED_ISA_DMA,
2108 static int scsi_map_queues(struct blk_mq_tag_set *set)
2110 struct Scsi_Host *shost = container_of(set, struct Scsi_Host, tag_set);
2112 if (shost->hostt->map_queues)
2113 return shost->hostt->map_queues(shost);
2114 return blk_mq_map_queues(set);
2117 static u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost)
2119 struct device *host_dev;
2120 u64 bounce_limit = 0xffffffff;
2122 if (shost->unchecked_isa_dma)
2123 return BLK_BOUNCE_ISA;
2125 * Platforms with virtual-DMA translation
2126 * hardware have no practical limit.
2128 if (!PCI_DMA_BUS_IS_PHYS)
2129 return BLK_BOUNCE_ANY;
2131 host_dev = scsi_get_device(shost);
2132 if (host_dev && host_dev->dma_mask)
2133 bounce_limit = (u64)dma_max_pfn(host_dev) << PAGE_SHIFT;
2135 return bounce_limit;
2138 void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
2140 struct device *dev = shost->dma_dev;
2142 queue_flag_set_unlocked(QUEUE_FLAG_SCSI_PASSTHROUGH, q);
2145 * this limit is imposed by hardware restrictions
2147 blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
2150 if (scsi_host_prot_dma(shost)) {
2151 shost->sg_prot_tablesize =
2152 min_not_zero(shost->sg_prot_tablesize,
2153 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
2154 BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
2155 blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
2158 blk_queue_max_hw_sectors(q, shost->max_sectors);
2159 blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost));
2160 blk_queue_segment_boundary(q, shost->dma_boundary);
2161 dma_set_seg_boundary(dev, shost->dma_boundary);
2163 blk_queue_max_segment_size(q, dma_get_max_seg_size(dev));
2165 if (!shost->use_clustering)
2166 q->limits.cluster = 0;
2169 * set a reasonable default alignment on word boundaries: the
2170 * host and device may alter it using
2171 * blk_queue_update_dma_alignment() later.
2173 blk_queue_dma_alignment(q, 0x03);
2175 EXPORT_SYMBOL_GPL(__scsi_init_queue);
2177 static int scsi_old_init_rq(struct request_queue *q, struct request *rq,
2180 struct Scsi_Host *shost = q->rq_alloc_data;
2181 const bool unchecked_isa_dma = shost->unchecked_isa_dma;
2182 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
2184 memset(cmd, 0, sizeof(*cmd));
2186 if (unchecked_isa_dma)
2187 cmd->flags |= SCMD_UNCHECKED_ISA_DMA;
2188 cmd->sense_buffer = scsi_alloc_sense_buffer(unchecked_isa_dma, gfp,
2190 if (!cmd->sense_buffer)
2192 cmd->req.sense = cmd->sense_buffer;
2194 if (scsi_host_get_prot(shost) >= SHOST_DIX_TYPE0_PROTECTION) {
2195 cmd->prot_sdb = kmem_cache_zalloc(scsi_sdb_cache, gfp);
2197 goto fail_free_sense;
2203 scsi_free_sense_buffer(unchecked_isa_dma, cmd->sense_buffer);
2208 static void scsi_old_exit_rq(struct request_queue *q, struct request *rq)
2210 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
2213 kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb);
2214 scsi_free_sense_buffer(cmd->flags & SCMD_UNCHECKED_ISA_DMA,
2218 struct request_queue *scsi_old_alloc_queue(struct scsi_device *sdev)
2220 struct Scsi_Host *shost = sdev->host;
2221 struct request_queue *q;
2223 q = blk_alloc_queue_node(GFP_KERNEL, NUMA_NO_NODE);
2226 q->cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
2227 q->rq_alloc_data = shost;
2228 q->request_fn = scsi_request_fn;
2229 q->init_rq_fn = scsi_old_init_rq;
2230 q->exit_rq_fn = scsi_old_exit_rq;
2231 q->initialize_rq_fn = scsi_initialize_rq;
2233 if (blk_init_allocated_queue(q) < 0) {
2234 blk_cleanup_queue(q);
2238 __scsi_init_queue(shost, q);
2239 blk_queue_prep_rq(q, scsi_prep_fn);
2240 blk_queue_unprep_rq(q, scsi_unprep_fn);
2241 blk_queue_softirq_done(q, scsi_softirq_done);
2242 blk_queue_rq_timed_out(q, scsi_times_out);
2243 blk_queue_lld_busy(q, scsi_lld_busy);
2247 static const struct blk_mq_ops scsi_mq_ops = {
2248 .get_budget = scsi_mq_get_budget,
2249 .put_budget = scsi_mq_put_budget,
2250 .queue_rq = scsi_queue_rq,
2251 .complete = scsi_softirq_done,
2252 .timeout = scsi_timeout,
2253 #ifdef CONFIG_BLK_DEBUG_FS
2254 .show_rq = scsi_show_rq,
2256 .init_request = scsi_mq_init_request,
2257 .exit_request = scsi_mq_exit_request,
2258 .initialize_rq_fn = scsi_initialize_rq,
2259 .map_queues = scsi_map_queues,
2262 struct request_queue *scsi_mq_alloc_queue(struct scsi_device *sdev)
2264 sdev->request_queue = blk_mq_init_queue(&sdev->host->tag_set);
2265 if (IS_ERR(sdev->request_queue))
2268 sdev->request_queue->queuedata = sdev;
2269 __scsi_init_queue(sdev->host, sdev->request_queue);
2270 return sdev->request_queue;
2273 int scsi_mq_setup_tags(struct Scsi_Host *shost)
2275 unsigned int cmd_size, sgl_size;
2277 sgl_size = scsi_mq_sgl_size(shost);
2278 cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size;
2279 if (scsi_host_get_prot(shost))
2280 cmd_size += sizeof(struct scsi_data_buffer) + sgl_size;
2282 memset(&shost->tag_set, 0, sizeof(shost->tag_set));
2283 shost->tag_set.ops = &scsi_mq_ops;
2284 shost->tag_set.nr_hw_queues = shost->nr_hw_queues ? : 1;
2285 shost->tag_set.queue_depth = shost->can_queue;
2286 shost->tag_set.cmd_size = cmd_size;
2287 shost->tag_set.numa_node = NUMA_NO_NODE;
2288 shost->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
2289 shost->tag_set.flags |=
2290 BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
2291 shost->tag_set.driver_data = shost;
2293 return blk_mq_alloc_tag_set(&shost->tag_set);
2296 void scsi_mq_destroy_tags(struct Scsi_Host *shost)
2298 blk_mq_free_tag_set(&shost->tag_set);
2302 * scsi_device_from_queue - return sdev associated with a request_queue
2303 * @q: The request queue to return the sdev from
2305 * Return the sdev associated with a request queue or NULL if the
2306 * request_queue does not reference a SCSI device.
2308 struct scsi_device *scsi_device_from_queue(struct request_queue *q)
2310 struct scsi_device *sdev = NULL;
2313 if (q->mq_ops == &scsi_mq_ops)
2314 sdev = q->queuedata;
2315 } else if (q->request_fn == scsi_request_fn)
2316 sdev = q->queuedata;
2317 if (!sdev || !get_device(&sdev->sdev_gendev))
2322 EXPORT_SYMBOL_GPL(scsi_device_from_queue);
2325 * Function: scsi_block_requests()
2327 * Purpose: Utility function used by low-level drivers to prevent further
2328 * commands from being queued to the device.
2330 * Arguments: shost - Host in question
2334 * Lock status: No locks are assumed held.
2336 * Notes: There is no timer nor any other means by which the requests
2337 * get unblocked other than the low-level driver calling
2338 * scsi_unblock_requests().
2340 void scsi_block_requests(struct Scsi_Host *shost)
2342 shost->host_self_blocked = 1;
2344 EXPORT_SYMBOL(scsi_block_requests);
2347 * Function: scsi_unblock_requests()
2349 * Purpose: Utility function used by low-level drivers to allow further
2350 * commands from being queued to the device.
2352 * Arguments: shost - Host in question
2356 * Lock status: No locks are assumed held.
2358 * Notes: There is no timer nor any other means by which the requests
2359 * get unblocked other than the low-level driver calling
2360 * scsi_unblock_requests().
2362 * This is done as an API function so that changes to the
2363 * internals of the scsi mid-layer won't require wholesale
2364 * changes to drivers that use this feature.
2366 void scsi_unblock_requests(struct Scsi_Host *shost)
2368 shost->host_self_blocked = 0;
2369 scsi_run_host_queues(shost);
2371 EXPORT_SYMBOL(scsi_unblock_requests);
2373 int __init scsi_init_queue(void)
2375 scsi_sdb_cache = kmem_cache_create("scsi_data_buffer",
2376 sizeof(struct scsi_data_buffer),
2378 if (!scsi_sdb_cache) {
2379 printk(KERN_ERR "SCSI: can't init scsi sdb cache\n");
2386 void scsi_exit_queue(void)
2388 kmem_cache_destroy(scsi_sense_cache);
2389 kmem_cache_destroy(scsi_sense_isadma_cache);
2390 kmem_cache_destroy(scsi_sdb_cache);
2394 * scsi_mode_select - issue a mode select
2395 * @sdev: SCSI device to be queried
2396 * @pf: Page format bit (1 == standard, 0 == vendor specific)
2397 * @sp: Save page bit (0 == don't save, 1 == save)
2398 * @modepage: mode page being requested
2399 * @buffer: request buffer (may not be smaller than eight bytes)
2400 * @len: length of request buffer.
2401 * @timeout: command timeout
2402 * @retries: number of retries before failing
2403 * @data: returns a structure abstracting the mode header data
2404 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2405 * must be SCSI_SENSE_BUFFERSIZE big.
2407 * Returns zero if successful; negative error number or scsi
2412 scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
2413 unsigned char *buffer, int len, int timeout, int retries,
2414 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2416 unsigned char cmd[10];
2417 unsigned char *real_buffer;
2420 memset(cmd, 0, sizeof(cmd));
2421 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
2423 if (sdev->use_10_for_ms) {
2426 real_buffer = kmalloc(8 + len, GFP_KERNEL);
2429 memcpy(real_buffer + 8, buffer, len);
2433 real_buffer[2] = data->medium_type;
2434 real_buffer[3] = data->device_specific;
2435 real_buffer[4] = data->longlba ? 0x01 : 0;
2437 real_buffer[6] = data->block_descriptor_length >> 8;
2438 real_buffer[7] = data->block_descriptor_length;
2440 cmd[0] = MODE_SELECT_10;
2444 if (len > 255 || data->block_descriptor_length > 255 ||
2448 real_buffer = kmalloc(4 + len, GFP_KERNEL);
2451 memcpy(real_buffer + 4, buffer, len);
2454 real_buffer[1] = data->medium_type;
2455 real_buffer[2] = data->device_specific;
2456 real_buffer[3] = data->block_descriptor_length;
2459 cmd[0] = MODE_SELECT;
2463 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
2464 sshdr, timeout, retries, NULL);
2468 EXPORT_SYMBOL_GPL(scsi_mode_select);
2471 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
2472 * @sdev: SCSI device to be queried
2473 * @dbd: set if mode sense will allow block descriptors to be returned
2474 * @modepage: mode page being requested
2475 * @buffer: request buffer (may not be smaller than eight bytes)
2476 * @len: length of request buffer.
2477 * @timeout: command timeout
2478 * @retries: number of retries before failing
2479 * @data: returns a structure abstracting the mode header data
2480 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2481 * must be SCSI_SENSE_BUFFERSIZE big.
2483 * Returns zero if unsuccessful, or the header offset (either 4
2484 * or 8 depending on whether a six or ten byte command was
2485 * issued) if successful.
2488 scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
2489 unsigned char *buffer, int len, int timeout, int retries,
2490 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2492 unsigned char cmd[12];
2495 int result, retry_count = retries;
2496 struct scsi_sense_hdr my_sshdr;
2498 memset(data, 0, sizeof(*data));
2499 memset(&cmd[0], 0, 12);
2500 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
2503 /* caller might not be interested in sense, but we need it */
2508 use_10_for_ms = sdev->use_10_for_ms;
2510 if (use_10_for_ms) {
2514 cmd[0] = MODE_SENSE_10;
2521 cmd[0] = MODE_SENSE;
2526 memset(buffer, 0, len);
2528 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
2529 sshdr, timeout, retries, NULL);
2531 /* This code looks awful: what it's doing is making sure an
2532 * ILLEGAL REQUEST sense return identifies the actual command
2533 * byte as the problem. MODE_SENSE commands can return
2534 * ILLEGAL REQUEST if the code page isn't supported */
2536 if (use_10_for_ms && !scsi_status_is_good(result) &&
2537 (driver_byte(result) & DRIVER_SENSE)) {
2538 if (scsi_sense_valid(sshdr)) {
2539 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
2540 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
2542 * Invalid command operation code
2544 sdev->use_10_for_ms = 0;
2550 if(scsi_status_is_good(result)) {
2551 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
2552 (modepage == 6 || modepage == 8))) {
2553 /* Initio breakage? */
2556 data->medium_type = 0;
2557 data->device_specific = 0;
2559 data->block_descriptor_length = 0;
2560 } else if(use_10_for_ms) {
2561 data->length = buffer[0]*256 + buffer[1] + 2;
2562 data->medium_type = buffer[2];
2563 data->device_specific = buffer[3];
2564 data->longlba = buffer[4] & 0x01;
2565 data->block_descriptor_length = buffer[6]*256
2568 data->length = buffer[0] + 1;
2569 data->medium_type = buffer[1];
2570 data->device_specific = buffer[2];
2571 data->block_descriptor_length = buffer[3];
2573 data->header_length = header_length;
2574 } else if ((status_byte(result) == CHECK_CONDITION) &&
2575 scsi_sense_valid(sshdr) &&
2576 sshdr->sense_key == UNIT_ATTENTION && retry_count) {
2583 EXPORT_SYMBOL(scsi_mode_sense);
2586 * scsi_test_unit_ready - test if unit is ready
2587 * @sdev: scsi device to change the state of.
2588 * @timeout: command timeout
2589 * @retries: number of retries before failing
2590 * @sshdr: outpout pointer for decoded sense information.
2592 * Returns zero if unsuccessful or an error if TUR failed. For
2593 * removable media, UNIT_ATTENTION sets ->changed flag.
2596 scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2597 struct scsi_sense_hdr *sshdr)
2600 TEST_UNIT_READY, 0, 0, 0, 0, 0,
2604 /* try to eat the UNIT_ATTENTION if there are enough retries */
2606 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
2607 timeout, retries, NULL);
2608 if (sdev->removable && scsi_sense_valid(sshdr) &&
2609 sshdr->sense_key == UNIT_ATTENTION)
2611 } while (scsi_sense_valid(sshdr) &&
2612 sshdr->sense_key == UNIT_ATTENTION && --retries);
2616 EXPORT_SYMBOL(scsi_test_unit_ready);
2619 * scsi_device_set_state - Take the given device through the device state model.
2620 * @sdev: scsi device to change the state of.
2621 * @state: state to change to.
2623 * Returns zero if successful or an error if the requested
2624 * transition is illegal.
2627 scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2629 enum scsi_device_state oldstate = sdev->sdev_state;
2631 if (state == oldstate)
2637 case SDEV_CREATED_BLOCK:
2648 case SDEV_TRANSPORT_OFFLINE:
2661 case SDEV_TRANSPORT_OFFLINE:
2669 case SDEV_TRANSPORT_OFFLINE:
2684 case SDEV_CREATED_BLOCK:
2691 case SDEV_CREATED_BLOCK:
2706 case SDEV_TRANSPORT_OFFLINE:
2718 case SDEV_TRANSPORT_OFFLINE:
2721 case SDEV_CREATED_BLOCK:
2729 sdev->sdev_state = state;
2733 SCSI_LOG_ERROR_RECOVERY(1,
2734 sdev_printk(KERN_ERR, sdev,
2735 "Illegal state transition %s->%s",
2736 scsi_device_state_name(oldstate),
2737 scsi_device_state_name(state))
2741 EXPORT_SYMBOL(scsi_device_set_state);
2744 * sdev_evt_emit - emit a single SCSI device uevent
2745 * @sdev: associated SCSI device
2746 * @evt: event to emit
2748 * Send a single uevent (scsi_event) to the associated scsi_device.
2750 static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2755 switch (evt->evt_type) {
2756 case SDEV_EVT_MEDIA_CHANGE:
2757 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2759 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2760 scsi_rescan_device(&sdev->sdev_gendev);
2761 envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2763 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2764 envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2766 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2767 envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2769 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2770 envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2772 case SDEV_EVT_LUN_CHANGE_REPORTED:
2773 envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2775 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2776 envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
2778 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2779 envp[idx++] = "SDEV_UA=POWER_ON_RESET_OCCURRED";
2788 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2792 * sdev_evt_thread - send a uevent for each scsi event
2793 * @work: work struct for scsi_device
2795 * Dispatch queued events to their associated scsi_device kobjects
2798 void scsi_evt_thread(struct work_struct *work)
2800 struct scsi_device *sdev;
2801 enum scsi_device_event evt_type;
2802 LIST_HEAD(event_list);
2804 sdev = container_of(work, struct scsi_device, event_work);
2806 for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
2807 if (test_and_clear_bit(evt_type, sdev->pending_events))
2808 sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
2811 struct scsi_event *evt;
2812 struct list_head *this, *tmp;
2813 unsigned long flags;
2815 spin_lock_irqsave(&sdev->list_lock, flags);
2816 list_splice_init(&sdev->event_list, &event_list);
2817 spin_unlock_irqrestore(&sdev->list_lock, flags);
2819 if (list_empty(&event_list))
2822 list_for_each_safe(this, tmp, &event_list) {
2823 evt = list_entry(this, struct scsi_event, node);
2824 list_del(&evt->node);
2825 scsi_evt_emit(sdev, evt);
2832 * sdev_evt_send - send asserted event to uevent thread
2833 * @sdev: scsi_device event occurred on
2834 * @evt: event to send
2836 * Assert scsi device event asynchronously.
2838 void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2840 unsigned long flags;
2843 /* FIXME: currently this check eliminates all media change events
2844 * for polled devices. Need to update to discriminate between AN
2845 * and polled events */
2846 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2852 spin_lock_irqsave(&sdev->list_lock, flags);
2853 list_add_tail(&evt->node, &sdev->event_list);
2854 schedule_work(&sdev->event_work);
2855 spin_unlock_irqrestore(&sdev->list_lock, flags);
2857 EXPORT_SYMBOL_GPL(sdev_evt_send);
2860 * sdev_evt_alloc - allocate a new scsi event
2861 * @evt_type: type of event to allocate
2862 * @gfpflags: GFP flags for allocation
2864 * Allocates and returns a new scsi_event.
2866 struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2869 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2873 evt->evt_type = evt_type;
2874 INIT_LIST_HEAD(&evt->node);
2876 /* evt_type-specific initialization, if any */
2878 case SDEV_EVT_MEDIA_CHANGE:
2879 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2880 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2881 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2882 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2883 case SDEV_EVT_LUN_CHANGE_REPORTED:
2884 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2885 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2893 EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2896 * sdev_evt_send_simple - send asserted event to uevent thread
2897 * @sdev: scsi_device event occurred on
2898 * @evt_type: type of event to send
2899 * @gfpflags: GFP flags for allocation
2901 * Assert scsi device event asynchronously, given an event type.
2903 void sdev_evt_send_simple(struct scsi_device *sdev,
2904 enum scsi_device_event evt_type, gfp_t gfpflags)
2906 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2908 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2913 sdev_evt_send(sdev, evt);
2915 EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2918 * scsi_request_fn_active() - number of kernel threads inside scsi_request_fn()
2919 * @sdev: SCSI device to count the number of scsi_request_fn() callers for.
2921 static int scsi_request_fn_active(struct scsi_device *sdev)
2923 struct request_queue *q = sdev->request_queue;
2924 int request_fn_active;
2926 WARN_ON_ONCE(sdev->host->use_blk_mq);
2928 spin_lock_irq(q->queue_lock);
2929 request_fn_active = q->request_fn_active;
2930 spin_unlock_irq(q->queue_lock);
2932 return request_fn_active;
2936 * scsi_wait_for_queuecommand() - wait for ongoing queuecommand() calls
2937 * @sdev: SCSI device pointer.
2939 * Wait until the ongoing shost->hostt->queuecommand() calls that are
2940 * invoked from scsi_request_fn() have finished.
2942 static void scsi_wait_for_queuecommand(struct scsi_device *sdev)
2944 WARN_ON_ONCE(sdev->host->use_blk_mq);
2946 while (scsi_request_fn_active(sdev))
2951 * scsi_device_quiesce - Block user issued commands.
2952 * @sdev: scsi device to quiesce.
2954 * This works by trying to transition to the SDEV_QUIESCE state
2955 * (which must be a legal transition). When the device is in this
2956 * state, only special requests will be accepted, all others will
2957 * be deferred. Since special requests may also be requeued requests,
2958 * a successful return doesn't guarantee the device will be
2959 * totally quiescent.
2961 * Must be called with user context, may sleep.
2963 * Returns zero if unsuccessful or an error if not.
2966 scsi_device_quiesce(struct scsi_device *sdev)
2968 struct request_queue *q = sdev->request_queue;
2972 * It is allowed to call scsi_device_quiesce() multiple times from
2973 * the same context but concurrent scsi_device_quiesce() calls are
2976 WARN_ON_ONCE(sdev->quiesced_by && sdev->quiesced_by != current);
2978 blk_set_preempt_only(q);
2980 blk_mq_freeze_queue(q);
2982 * Ensure that the effect of blk_set_preempt_only() will be visible
2983 * for percpu_ref_tryget() callers that occur after the queue
2984 * unfreeze even if the queue was already frozen before this function
2985 * was called. See also https://lwn.net/Articles/573497/.
2988 blk_mq_unfreeze_queue(q);
2990 mutex_lock(&sdev->state_mutex);
2991 err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2993 sdev->quiesced_by = current;
2995 blk_clear_preempt_only(q);
2996 mutex_unlock(&sdev->state_mutex);
3000 EXPORT_SYMBOL(scsi_device_quiesce);
3003 * scsi_device_resume - Restart user issued commands to a quiesced device.
3004 * @sdev: scsi device to resume.
3006 * Moves the device from quiesced back to running and restarts the
3009 * Must be called with user context, may sleep.
3011 void scsi_device_resume(struct scsi_device *sdev)
3013 /* check if the device state was mutated prior to resume, and if
3014 * so assume the state is being managed elsewhere (for example
3015 * device deleted during suspend)
3017 mutex_lock(&sdev->state_mutex);
3018 WARN_ON_ONCE(!sdev->quiesced_by);
3019 sdev->quiesced_by = NULL;
3020 blk_clear_preempt_only(sdev->request_queue);
3021 if (sdev->sdev_state == SDEV_QUIESCE)
3022 scsi_device_set_state(sdev, SDEV_RUNNING);
3023 mutex_unlock(&sdev->state_mutex);
3025 EXPORT_SYMBOL(scsi_device_resume);
3028 device_quiesce_fn(struct scsi_device *sdev, void *data)
3030 scsi_device_quiesce(sdev);
3034 scsi_target_quiesce(struct scsi_target *starget)
3036 starget_for_each_device(starget, NULL, device_quiesce_fn);
3038 EXPORT_SYMBOL(scsi_target_quiesce);
3041 device_resume_fn(struct scsi_device *sdev, void *data)
3043 scsi_device_resume(sdev);
3047 scsi_target_resume(struct scsi_target *starget)
3049 starget_for_each_device(starget, NULL, device_resume_fn);
3051 EXPORT_SYMBOL(scsi_target_resume);
3054 * scsi_internal_device_block_nowait - try to transition to the SDEV_BLOCK state
3055 * @sdev: device to block
3057 * Pause SCSI command processing on the specified device. Does not sleep.
3059 * Returns zero if successful or a negative error code upon failure.
3062 * This routine transitions the device to the SDEV_BLOCK state (which must be
3063 * a legal transition). When the device is in this state, command processing
3064 * is paused until the device leaves the SDEV_BLOCK state. See also
3065 * scsi_internal_device_unblock_nowait().
3067 int scsi_internal_device_block_nowait(struct scsi_device *sdev)
3069 struct request_queue *q = sdev->request_queue;
3070 unsigned long flags;
3073 err = scsi_device_set_state(sdev, SDEV_BLOCK);
3075 err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
3082 * The device has transitioned to SDEV_BLOCK. Stop the
3083 * block layer from calling the midlayer with this device's
3087 blk_mq_quiesce_queue_nowait(q);
3089 spin_lock_irqsave(q->queue_lock, flags);
3091 spin_unlock_irqrestore(q->queue_lock, flags);
3096 EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait);
3099 * scsi_internal_device_block - try to transition to the SDEV_BLOCK state
3100 * @sdev: device to block
3102 * Pause SCSI command processing on the specified device and wait until all
3103 * ongoing scsi_request_fn() / scsi_queue_rq() calls have finished. May sleep.
3105 * Returns zero if successful or a negative error code upon failure.
3108 * This routine transitions the device to the SDEV_BLOCK state (which must be
3109 * a legal transition). When the device is in this state, command processing
3110 * is paused until the device leaves the SDEV_BLOCK state. See also
3111 * scsi_internal_device_unblock().
3113 * To do: avoid that scsi_send_eh_cmnd() calls queuecommand() after
3114 * scsi_internal_device_block() has blocked a SCSI device and also
3115 * remove the rport mutex lock and unlock calls from srp_queuecommand().
3117 static int scsi_internal_device_block(struct scsi_device *sdev)
3119 struct request_queue *q = sdev->request_queue;
3122 mutex_lock(&sdev->state_mutex);
3123 err = scsi_internal_device_block_nowait(sdev);
3126 blk_mq_quiesce_queue(q);
3128 scsi_wait_for_queuecommand(sdev);
3130 mutex_unlock(&sdev->state_mutex);
3135 void scsi_start_queue(struct scsi_device *sdev)
3137 struct request_queue *q = sdev->request_queue;
3138 unsigned long flags;
3141 blk_mq_unquiesce_queue(q);
3143 spin_lock_irqsave(q->queue_lock, flags);
3145 spin_unlock_irqrestore(q->queue_lock, flags);
3150 * scsi_internal_device_unblock_nowait - resume a device after a block request
3151 * @sdev: device to resume
3152 * @new_state: state to set the device to after unblocking
3154 * Restart the device queue for a previously suspended SCSI device. Does not
3157 * Returns zero if successful or a negative error code upon failure.
3160 * This routine transitions the device to the SDEV_RUNNING state or to one of
3161 * the offline states (which must be a legal transition) allowing the midlayer
3162 * to goose the queue for this device.
3164 int scsi_internal_device_unblock_nowait(struct scsi_device *sdev,
3165 enum scsi_device_state new_state)
3168 * Try to transition the scsi device to SDEV_RUNNING or one of the
3169 * offlined states and goose the device queue if successful.
3171 switch (sdev->sdev_state) {
3173 case SDEV_TRANSPORT_OFFLINE:
3174 sdev->sdev_state = new_state;
3176 case SDEV_CREATED_BLOCK:
3177 if (new_state == SDEV_TRANSPORT_OFFLINE ||
3178 new_state == SDEV_OFFLINE)
3179 sdev->sdev_state = new_state;
3181 sdev->sdev_state = SDEV_CREATED;
3189 scsi_start_queue(sdev);
3193 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock_nowait);
3196 * scsi_internal_device_unblock - resume a device after a block request
3197 * @sdev: device to resume
3198 * @new_state: state to set the device to after unblocking
3200 * Restart the device queue for a previously suspended SCSI device. May sleep.
3202 * Returns zero if successful or a negative error code upon failure.
3205 * This routine transitions the device to the SDEV_RUNNING state or to one of
3206 * the offline states (which must be a legal transition) allowing the midlayer
3207 * to goose the queue for this device.
3209 static int scsi_internal_device_unblock(struct scsi_device *sdev,
3210 enum scsi_device_state new_state)
3214 mutex_lock(&sdev->state_mutex);
3215 ret = scsi_internal_device_unblock_nowait(sdev, new_state);
3216 mutex_unlock(&sdev->state_mutex);
3222 device_block(struct scsi_device *sdev, void *data)
3224 scsi_internal_device_block(sdev);
3228 target_block(struct device *dev, void *data)
3230 if (scsi_is_target_device(dev))
3231 starget_for_each_device(to_scsi_target(dev), NULL,
3237 scsi_target_block(struct device *dev)
3239 if (scsi_is_target_device(dev))
3240 starget_for_each_device(to_scsi_target(dev), NULL,
3243 device_for_each_child(dev, NULL, target_block);
3245 EXPORT_SYMBOL_GPL(scsi_target_block);
3248 device_unblock(struct scsi_device *sdev, void *data)
3250 scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
3254 target_unblock(struct device *dev, void *data)
3256 if (scsi_is_target_device(dev))
3257 starget_for_each_device(to_scsi_target(dev), data,
3263 scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
3265 if (scsi_is_target_device(dev))
3266 starget_for_each_device(to_scsi_target(dev), &new_state,
3269 device_for_each_child(dev, &new_state, target_unblock);
3271 EXPORT_SYMBOL_GPL(scsi_target_unblock);
3274 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
3275 * @sgl: scatter-gather list
3276 * @sg_count: number of segments in sg
3277 * @offset: offset in bytes into sg, on return offset into the mapped area
3278 * @len: bytes to map, on return number of bytes mapped
3280 * Returns virtual address of the start of the mapped page
3282 void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
3283 size_t *offset, size_t *len)
3286 size_t sg_len = 0, len_complete = 0;
3287 struct scatterlist *sg;
3290 WARN_ON(!irqs_disabled());
3292 for_each_sg(sgl, sg, sg_count, i) {
3293 len_complete = sg_len; /* Complete sg-entries */
3294 sg_len += sg->length;
3295 if (sg_len > *offset)
3299 if (unlikely(i == sg_count)) {
3300 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
3302 __func__, sg_len, *offset, sg_count);
3307 /* Offset starting from the beginning of first page in this sg-entry */
3308 *offset = *offset - len_complete + sg->offset;
3310 /* Assumption: contiguous pages can be accessed as "page + i" */
3311 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
3312 *offset &= ~PAGE_MASK;
3314 /* Bytes in this sg-entry from *offset to the end of the page */
3315 sg_len = PAGE_SIZE - *offset;
3319 return kmap_atomic(page);
3321 EXPORT_SYMBOL(scsi_kmap_atomic_sg);
3324 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
3325 * @virt: virtual address to be unmapped
3327 void scsi_kunmap_atomic_sg(void *virt)
3329 kunmap_atomic(virt);
3331 EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
3333 void sdev_disable_disk_events(struct scsi_device *sdev)
3335 atomic_inc(&sdev->disk_events_disable_depth);
3337 EXPORT_SYMBOL(sdev_disable_disk_events);
3339 void sdev_enable_disk_events(struct scsi_device *sdev)
3341 if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0))
3343 atomic_dec(&sdev->disk_events_disable_depth);
3345 EXPORT_SYMBOL(sdev_enable_disk_events);
3348 * scsi_vpd_lun_id - return a unique device identification
3349 * @sdev: SCSI device
3350 * @id: buffer for the identification
3351 * @id_len: length of the buffer
3353 * Copies a unique device identification into @id based
3354 * on the information in the VPD page 0x83 of the device.
3355 * The string will be formatted as a SCSI name string.
3357 * Returns the length of the identification or error on failure.
3358 * If the identifier is longer than the supplied buffer the actual
3359 * identifier length is returned and the buffer is not zero-padded.
3361 int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len)
3363 u8 cur_id_type = 0xff;
3365 const unsigned char *d, *cur_id_str;
3366 const struct scsi_vpd *vpd_pg83;
3367 int id_size = -EINVAL;
3370 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3377 * Look for the correct descriptor.
3378 * Order of preference for lun descriptor:
3379 * - SCSI name string
3380 * - NAA IEEE Registered Extended
3381 * - EUI-64 based 16-byte
3382 * - EUI-64 based 12-byte
3383 * - NAA IEEE Registered
3384 * - NAA IEEE Extended
3386 * as longer descriptors reduce the likelyhood
3387 * of identification clashes.
3390 /* The id string must be at least 20 bytes + terminating NULL byte */
3396 memset(id, 0, id_len);
3397 d = vpd_pg83->data + 4;
3398 while (d < vpd_pg83->data + vpd_pg83->len) {
3399 /* Skip designators not referring to the LUN */
3400 if ((d[1] & 0x30) != 0x00)
3403 switch (d[1] & 0xf) {
3406 if (cur_id_size > d[3])
3408 /* Prefer anything */
3409 if (cur_id_type > 0x01 && cur_id_type != 0xff)
3412 if (cur_id_size + 4 > id_len)
3413 cur_id_size = id_len - 4;
3415 cur_id_type = d[1] & 0xf;
3416 id_size = snprintf(id, id_len, "t10.%*pE",
3417 cur_id_size, cur_id_str);
3421 if (cur_id_size > d[3])
3423 /* Prefer NAA IEEE Registered Extended */
3424 if (cur_id_type == 0x3 &&
3425 cur_id_size == d[3])
3429 cur_id_type = d[1] & 0xf;
3430 switch (cur_id_size) {
3432 id_size = snprintf(id, id_len,
3437 id_size = snprintf(id, id_len,
3442 id_size = snprintf(id, id_len,
3453 if (cur_id_size > d[3])
3457 cur_id_type = d[1] & 0xf;
3458 switch (cur_id_size) {
3460 id_size = snprintf(id, id_len,
3465 id_size = snprintf(id, id_len,
3475 /* SCSI name string */
3476 if (cur_id_size + 4 > d[3])
3478 /* Prefer others for truncated descriptor */
3479 if (cur_id_size && d[3] > id_len)
3481 cur_id_size = id_size = d[3];
3483 cur_id_type = d[1] & 0xf;
3484 if (cur_id_size >= id_len)
3485 cur_id_size = id_len - 1;
3486 memcpy(id, cur_id_str, cur_id_size);
3487 /* Decrease priority for truncated descriptor */
3488 if (cur_id_size != id_size)
3501 EXPORT_SYMBOL(scsi_vpd_lun_id);
3504 * scsi_vpd_tpg_id - return a target port group identifier
3505 * @sdev: SCSI device
3507 * Returns the Target Port Group identifier from the information
3508 * froom VPD page 0x83 of the device.
3510 * Returns the identifier or error on failure.
3512 int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id)
3514 const unsigned char *d;
3515 const struct scsi_vpd *vpd_pg83;
3516 int group_id = -EAGAIN, rel_port = -1;
3519 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3525 d = vpd_pg83->data + 4;
3526 while (d < vpd_pg83->data + vpd_pg83->len) {
3527 switch (d[1] & 0xf) {
3529 /* Relative target port */
3530 rel_port = get_unaligned_be16(&d[6]);
3533 /* Target port group */
3534 group_id = get_unaligned_be16(&d[6]);
3543 if (group_id >= 0 && rel_id && rel_port != -1)
3548 EXPORT_SYMBOL(scsi_vpd_tpg_id);