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, int 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, 1);
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;
677 * In the MQ case the command gets freed by __blk_mq_end_request,
678 * so we have to do all cleanup that depends on it earlier.
680 * We also can't kick the queues from irq context, so we
681 * will have to defer it to a workqueue.
683 scsi_mq_uninit_cmd(cmd);
685 __blk_mq_end_request(req, error);
687 if (scsi_target(sdev)->single_lun ||
688 !list_empty(&sdev->host->starved_list))
689 kblockd_schedule_work(&sdev->requeue_work);
691 blk_mq_run_hw_queues(q, true);
696 scsi_release_bidi_buffers(cmd);
697 scsi_release_buffers(cmd);
698 scsi_put_command(cmd);
700 spin_lock_irqsave(q->queue_lock, flags);
701 blk_finish_request(req, error);
702 spin_unlock_irqrestore(q->queue_lock, flags);
707 put_device(&sdev->sdev_gendev);
712 * __scsi_error_from_host_byte - translate SCSI error code into errno
713 * @cmd: SCSI command (unused)
714 * @result: scsi error code
716 * Translate SCSI error code into block errors.
718 static blk_status_t __scsi_error_from_host_byte(struct scsi_cmnd *cmd,
721 switch (host_byte(result)) {
722 case DID_TRANSPORT_FAILFAST:
723 return BLK_STS_TRANSPORT;
724 case DID_TARGET_FAILURE:
725 set_host_byte(cmd, DID_OK);
726 return BLK_STS_TARGET;
727 case DID_NEXUS_FAILURE:
728 return BLK_STS_NEXUS;
729 case DID_ALLOC_FAILURE:
730 set_host_byte(cmd, DID_OK);
731 return BLK_STS_NOSPC;
732 case DID_MEDIUM_ERROR:
733 set_host_byte(cmd, DID_OK);
734 return BLK_STS_MEDIUM;
736 return BLK_STS_IOERR;
741 * Function: scsi_io_completion()
743 * Purpose: Completion processing for block device I/O requests.
745 * Arguments: cmd - command that is finished.
747 * Lock status: Assumed that no lock is held upon entry.
751 * Notes: We will finish off the specified number of sectors. If we
752 * are done, the command block will be released and the queue
753 * function will be goosed. If we are not done then we have to
754 * figure out what to do next:
756 * a) We can call scsi_requeue_command(). The request
757 * will be unprepared and put back on the queue. Then
758 * a new command will be created for it. This should
759 * be used if we made forward progress, or if we want
760 * to switch from READ(10) to READ(6) for example.
762 * b) We can call __scsi_queue_insert(). The request will
763 * be put back on the queue and retried using the same
764 * command as before, possibly after a delay.
766 * c) We can call scsi_end_request() with -EIO to fail
767 * the remainder of the request.
769 void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
771 int result = cmd->result;
772 struct request_queue *q = cmd->device->request_queue;
773 struct request *req = cmd->request;
774 blk_status_t error = BLK_STS_OK;
775 struct scsi_sense_hdr sshdr;
776 bool sense_valid = false;
777 int sense_deferred = 0, level = 0;
778 enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,
779 ACTION_DELAYED_RETRY} action;
780 unsigned long wait_for = (cmd->allowed + 1) * req->timeout;
783 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
785 sense_deferred = scsi_sense_is_deferred(&sshdr);
788 if (blk_rq_is_passthrough(req)) {
792 * SG_IO wants current and deferred errors
794 scsi_req(req)->sense_len =
795 min(8 + cmd->sense_buffer[7],
796 SCSI_SENSE_BUFFERSIZE);
799 error = __scsi_error_from_host_byte(cmd, result);
802 * __scsi_error_from_host_byte may have reset the host_byte
804 scsi_req(req)->result = cmd->result;
805 scsi_req(req)->resid_len = scsi_get_resid(cmd);
807 if (scsi_bidi_cmnd(cmd)) {
809 * Bidi commands Must be complete as a whole,
810 * both sides at once.
812 scsi_req(req->next_rq)->resid_len = scsi_in(cmd)->resid;
813 if (scsi_end_request(req, BLK_STS_OK, blk_rq_bytes(req),
814 blk_rq_bytes(req->next_rq)))
818 } else if (blk_rq_bytes(req) == 0 && result && !sense_deferred) {
820 * Flush commands do not transfers any data, and thus cannot use
821 * good_bytes != blk_rq_bytes(req) as the signal for an error.
822 * This sets the error explicitly for the problem case.
824 error = __scsi_error_from_host_byte(cmd, result);
827 /* no bidi support for !blk_rq_is_passthrough yet */
828 BUG_ON(blk_bidi_rq(req));
831 * Next deal with any sectors which we were able to correctly
834 SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd,
835 "%u sectors total, %d bytes done.\n",
836 blk_rq_sectors(req), good_bytes));
839 * Recovered errors need reporting, but they're always treated as
840 * success, so fiddle the result code here. For passthrough requests
841 * we already took a copy of the original into sreq->result which
842 * is what gets returned to the user
844 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
845 /* if ATA PASS-THROUGH INFORMATION AVAILABLE skip
846 * print since caller wants ATA registers. Only occurs on
847 * SCSI ATA PASS_THROUGH commands when CK_COND=1
849 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
851 else if (!(req->rq_flags & RQF_QUIET))
852 scsi_print_sense(cmd);
854 /* for passthrough error may be set */
859 * special case: failed zero length commands always need to
860 * drop down into the retry code. Otherwise, if we finished
861 * all bytes in the request we are done now.
863 if (!(blk_rq_bytes(req) == 0 && error) &&
864 !scsi_end_request(req, error, good_bytes, 0))
868 * Kill remainder if no retrys.
870 if (error && scsi_noretry_cmd(cmd)) {
871 if (scsi_end_request(req, error, blk_rq_bytes(req), 0))
877 * If there had been no error, but we have leftover bytes in the
878 * requeues just queue the command up again.
883 error = __scsi_error_from_host_byte(cmd, result);
885 if (host_byte(result) == DID_RESET) {
886 /* Third party bus reset or reset for error recovery
887 * reasons. Just retry the command and see what
890 action = ACTION_RETRY;
891 } else if (sense_valid && !sense_deferred) {
892 switch (sshdr.sense_key) {
894 if (cmd->device->removable) {
895 /* Detected disc change. Set a bit
896 * and quietly refuse further access.
898 cmd->device->changed = 1;
899 action = ACTION_FAIL;
901 /* Must have been a power glitch, or a
902 * bus reset. Could not have been a
903 * media change, so we just retry the
904 * command and see what happens.
906 action = ACTION_RETRY;
909 case ILLEGAL_REQUEST:
910 /* If we had an ILLEGAL REQUEST returned, then
911 * we may have performed an unsupported
912 * command. The only thing this should be
913 * would be a ten byte read where only a six
914 * byte read was supported. Also, on a system
915 * where READ CAPACITY failed, we may have
916 * read past the end of the disk.
918 if ((cmd->device->use_10_for_rw &&
919 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
920 (cmd->cmnd[0] == READ_10 ||
921 cmd->cmnd[0] == WRITE_10)) {
922 /* This will issue a new 6-byte command. */
923 cmd->device->use_10_for_rw = 0;
924 action = ACTION_REPREP;
925 } else if (sshdr.asc == 0x10) /* DIX */ {
926 action = ACTION_FAIL;
927 error = BLK_STS_PROTECTION;
928 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
929 } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
930 action = ACTION_FAIL;
931 error = BLK_STS_TARGET;
933 action = ACTION_FAIL;
935 case ABORTED_COMMAND:
936 action = ACTION_FAIL;
937 if (sshdr.asc == 0x10) /* DIF */
938 error = BLK_STS_PROTECTION;
941 /* If the device is in the process of becoming
942 * ready, or has a temporary blockage, retry.
944 if (sshdr.asc == 0x04) {
945 switch (sshdr.ascq) {
946 case 0x01: /* becoming ready */
947 case 0x04: /* format in progress */
948 case 0x05: /* rebuild in progress */
949 case 0x06: /* recalculation in progress */
950 case 0x07: /* operation in progress */
951 case 0x08: /* Long write in progress */
952 case 0x09: /* self test in progress */
953 case 0x14: /* space allocation in progress */
954 action = ACTION_DELAYED_RETRY;
957 action = ACTION_FAIL;
961 action = ACTION_FAIL;
963 case VOLUME_OVERFLOW:
964 /* See SSC3rXX or current. */
965 action = ACTION_FAIL;
968 action = ACTION_FAIL;
972 action = ACTION_FAIL;
974 if (action != ACTION_FAIL &&
975 time_before(cmd->jiffies_at_alloc + wait_for, jiffies))
976 action = ACTION_FAIL;
980 /* Give up and fail the remainder of the request */
981 if (!(req->rq_flags & RQF_QUIET)) {
982 static DEFINE_RATELIMIT_STATE(_rs,
983 DEFAULT_RATELIMIT_INTERVAL,
984 DEFAULT_RATELIMIT_BURST);
986 if (unlikely(scsi_logging_level))
987 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
988 SCSI_LOG_MLCOMPLETE_BITS);
991 * if logging is enabled the failure will be printed
992 * in scsi_log_completion(), so avoid duplicate messages
994 if (!level && __ratelimit(&_rs)) {
995 scsi_print_result(cmd, NULL, FAILED);
996 if (driver_byte(result) & DRIVER_SENSE)
997 scsi_print_sense(cmd);
998 scsi_print_command(cmd);
1001 if (!scsi_end_request(req, error, blk_rq_err_bytes(req), 0))
1006 /* Unprep the request and put it back at the head of the queue.
1007 * A new command will be prepared and issued.
1010 scsi_mq_requeue_cmd(cmd);
1012 scsi_release_buffers(cmd);
1013 scsi_requeue_command(q, cmd);
1017 /* Retry the same command immediately */
1018 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, 0);
1020 case ACTION_DELAYED_RETRY:
1021 /* Retry the same command after a delay */
1022 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, 0);
1027 static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb)
1032 * If sg table allocation fails, requeue request later.
1034 if (unlikely(sg_alloc_table_chained(&sdb->table,
1035 blk_rq_nr_phys_segments(req), sdb->table.sgl)))
1036 return BLKPREP_DEFER;
1039 * Next, walk the list, and fill in the addresses and sizes of
1042 count = blk_rq_map_sg(req->q, req, sdb->table.sgl);
1043 BUG_ON(count > sdb->table.nents);
1044 sdb->table.nents = count;
1045 sdb->length = blk_rq_payload_bytes(req);
1050 * Function: scsi_init_io()
1052 * Purpose: SCSI I/O initialize function.
1054 * Arguments: cmd - Command descriptor we wish to initialize
1056 * Returns: 0 on success
1057 * BLKPREP_DEFER if the failure is retryable
1058 * BLKPREP_KILL if the failure is fatal
1060 int scsi_init_io(struct scsi_cmnd *cmd)
1062 struct scsi_device *sdev = cmd->device;
1063 struct request *rq = cmd->request;
1064 bool is_mq = (rq->mq_ctx != NULL);
1065 int error = BLKPREP_KILL;
1067 if (WARN_ON_ONCE(!blk_rq_nr_phys_segments(rq)))
1070 error = scsi_init_sgtable(rq, &cmd->sdb);
1074 if (blk_bidi_rq(rq)) {
1075 if (!rq->q->mq_ops) {
1076 struct scsi_data_buffer *bidi_sdb =
1077 kmem_cache_zalloc(scsi_sdb_cache, GFP_ATOMIC);
1079 error = BLKPREP_DEFER;
1083 rq->next_rq->special = bidi_sdb;
1086 error = scsi_init_sgtable(rq->next_rq, rq->next_rq->special);
1091 if (blk_integrity_rq(rq)) {
1092 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1095 if (prot_sdb == NULL) {
1097 * This can happen if someone (e.g. multipath)
1098 * queues a command to a device on an adapter
1099 * that does not support DIX.
1102 error = BLKPREP_KILL;
1106 ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
1108 if (sg_alloc_table_chained(&prot_sdb->table, ivecs,
1109 prot_sdb->table.sgl)) {
1110 error = BLKPREP_DEFER;
1114 count = blk_rq_map_integrity_sg(rq->q, rq->bio,
1115 prot_sdb->table.sgl);
1116 BUG_ON(unlikely(count > ivecs));
1117 BUG_ON(unlikely(count > queue_max_integrity_segments(rq->q)));
1119 cmd->prot_sdb = prot_sdb;
1120 cmd->prot_sdb->table.nents = count;
1126 scsi_mq_free_sgtables(cmd);
1128 scsi_release_buffers(cmd);
1129 cmd->request->special = NULL;
1130 scsi_put_command(cmd);
1131 put_device(&sdev->sdev_gendev);
1135 EXPORT_SYMBOL(scsi_init_io);
1138 * scsi_initialize_rq - initialize struct scsi_cmnd partially
1139 * @rq: Request associated with the SCSI command to be initialized.
1141 * This function initializes the members of struct scsi_cmnd that must be
1142 * initialized before request processing starts and that won't be
1143 * reinitialized if a SCSI command is requeued.
1145 * Called from inside blk_get_request() for pass-through requests and from
1146 * inside scsi_init_command() for filesystem requests.
1148 static void scsi_initialize_rq(struct request *rq)
1150 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1152 scsi_req_init(&cmd->req);
1153 cmd->jiffies_at_alloc = jiffies;
1157 /* Add a command to the list used by the aacraid and dpt_i2o drivers */
1158 void scsi_add_cmd_to_list(struct scsi_cmnd *cmd)
1160 struct scsi_device *sdev = cmd->device;
1161 struct Scsi_Host *shost = sdev->host;
1162 unsigned long flags;
1164 if (shost->use_cmd_list) {
1165 spin_lock_irqsave(&sdev->list_lock, flags);
1166 list_add_tail(&cmd->list, &sdev->cmd_list);
1167 spin_unlock_irqrestore(&sdev->list_lock, flags);
1171 /* Remove a command from the list used by the aacraid and dpt_i2o drivers */
1172 void scsi_del_cmd_from_list(struct scsi_cmnd *cmd)
1174 struct scsi_device *sdev = cmd->device;
1175 struct Scsi_Host *shost = sdev->host;
1176 unsigned long flags;
1178 if (shost->use_cmd_list) {
1179 spin_lock_irqsave(&sdev->list_lock, flags);
1180 BUG_ON(list_empty(&cmd->list));
1181 list_del_init(&cmd->list);
1182 spin_unlock_irqrestore(&sdev->list_lock, flags);
1186 /* Called after a request has been started. */
1187 void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd)
1189 void *buf = cmd->sense_buffer;
1190 void *prot = cmd->prot_sdb;
1191 struct request *rq = blk_mq_rq_from_pdu(cmd);
1192 unsigned int flags = cmd->flags & SCMD_PRESERVED_FLAGS;
1193 unsigned long jiffies_at_alloc;
1196 if (!blk_rq_is_scsi(rq) && !(flags & SCMD_INITIALIZED)) {
1197 flags |= SCMD_INITIALIZED;
1198 scsi_initialize_rq(rq);
1201 jiffies_at_alloc = cmd->jiffies_at_alloc;
1202 retries = cmd->retries;
1203 /* zero out the cmd, except for the embedded scsi_request */
1204 memset((char *)cmd + sizeof(cmd->req), 0,
1205 sizeof(*cmd) - sizeof(cmd->req) + dev->host->hostt->cmd_size);
1208 cmd->sense_buffer = buf;
1209 cmd->prot_sdb = prot;
1211 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
1212 cmd->jiffies_at_alloc = jiffies_at_alloc;
1213 cmd->retries = retries;
1215 scsi_add_cmd_to_list(cmd);
1218 static int scsi_setup_scsi_cmnd(struct scsi_device *sdev, struct request *req)
1220 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1223 * Passthrough requests may transfer data, in which case they must
1224 * a bio attached to them. Or they might contain a SCSI command
1225 * that does not transfer data, in which case they may optionally
1226 * submit a request without an attached bio.
1229 int ret = scsi_init_io(cmd);
1233 BUG_ON(blk_rq_bytes(req));
1235 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1238 cmd->cmd_len = scsi_req(req)->cmd_len;
1239 cmd->cmnd = scsi_req(req)->cmd;
1240 cmd->transfersize = blk_rq_bytes(req);
1241 cmd->allowed = scsi_req(req)->retries;
1246 * Setup a normal block command. These are simple request from filesystems
1247 * that still need to be translated to SCSI CDBs from the ULD.
1249 static int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
1251 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1253 if (unlikely(sdev->handler && sdev->handler->prep_fn)) {
1254 int ret = sdev->handler->prep_fn(sdev, req);
1255 if (ret != BLKPREP_OK)
1259 cmd->cmnd = scsi_req(req)->cmd = scsi_req(req)->__cmd;
1260 memset(cmd->cmnd, 0, BLK_MAX_CDB);
1261 return scsi_cmd_to_driver(cmd)->init_command(cmd);
1264 static int scsi_setup_cmnd(struct scsi_device *sdev, struct request *req)
1266 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1268 if (!blk_rq_bytes(req))
1269 cmd->sc_data_direction = DMA_NONE;
1270 else if (rq_data_dir(req) == WRITE)
1271 cmd->sc_data_direction = DMA_TO_DEVICE;
1273 cmd->sc_data_direction = DMA_FROM_DEVICE;
1275 if (blk_rq_is_scsi(req))
1276 return scsi_setup_scsi_cmnd(sdev, req);
1278 return scsi_setup_fs_cmnd(sdev, req);
1282 scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
1284 int ret = BLKPREP_OK;
1287 * If the device is not in running state we will reject some
1290 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
1291 switch (sdev->sdev_state) {
1293 case SDEV_TRANSPORT_OFFLINE:
1295 * If the device is offline we refuse to process any
1296 * commands. The device must be brought online
1297 * before trying any recovery commands.
1299 sdev_printk(KERN_ERR, sdev,
1300 "rejecting I/O to offline device\n");
1305 * If the device is fully deleted, we refuse to
1306 * process any commands as well.
1308 sdev_printk(KERN_ERR, sdev,
1309 "rejecting I/O to dead device\n");
1313 case SDEV_CREATED_BLOCK:
1314 ret = BLKPREP_DEFER;
1318 * If the devices is blocked we defer normal commands.
1320 if (req && !(req->rq_flags & RQF_PREEMPT))
1321 ret = BLKPREP_DEFER;
1325 * For any other not fully online state we only allow
1326 * special commands. In particular any user initiated
1327 * command is not allowed.
1329 if (req && !(req->rq_flags & RQF_PREEMPT))
1338 scsi_prep_return(struct request_queue *q, struct request *req, int ret)
1340 struct scsi_device *sdev = q->queuedata;
1344 case BLKPREP_INVALID:
1345 scsi_req(req)->result = DID_NO_CONNECT << 16;
1346 /* release the command and kill it */
1348 struct scsi_cmnd *cmd = req->special;
1349 scsi_release_buffers(cmd);
1350 scsi_put_command(cmd);
1351 put_device(&sdev->sdev_gendev);
1352 req->special = NULL;
1357 * If we defer, the blk_peek_request() returns NULL, but the
1358 * queue must be restarted, so we schedule a callback to happen
1361 if (atomic_read(&sdev->device_busy) == 0)
1362 blk_delay_queue(q, SCSI_QUEUE_DELAY);
1365 req->rq_flags |= RQF_DONTPREP;
1371 static int scsi_prep_fn(struct request_queue *q, struct request *req)
1373 struct scsi_device *sdev = q->queuedata;
1374 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1377 ret = scsi_prep_state_check(sdev, req);
1378 if (ret != BLKPREP_OK)
1381 if (!req->special) {
1382 /* Bail if we can't get a reference to the device */
1383 if (unlikely(!get_device(&sdev->sdev_gendev))) {
1384 ret = BLKPREP_DEFER;
1388 scsi_init_command(sdev, cmd);
1392 cmd->tag = req->tag;
1394 cmd->prot_op = SCSI_PROT_NORMAL;
1396 ret = scsi_setup_cmnd(sdev, req);
1398 return scsi_prep_return(q, req, ret);
1401 static void scsi_unprep_fn(struct request_queue *q, struct request *req)
1403 scsi_uninit_cmd(blk_mq_rq_to_pdu(req));
1407 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1410 * Called with the queue_lock held.
1412 static inline int scsi_dev_queue_ready(struct request_queue *q,
1413 struct scsi_device *sdev)
1417 busy = atomic_inc_return(&sdev->device_busy) - 1;
1418 if (atomic_read(&sdev->device_blocked)) {
1423 * unblock after device_blocked iterates to zero
1425 if (atomic_dec_return(&sdev->device_blocked) > 0) {
1427 * For the MQ case we take care of this in the caller.
1430 blk_delay_queue(q, SCSI_QUEUE_DELAY);
1433 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev,
1434 "unblocking device at zero depth\n"));
1437 if (busy >= sdev->queue_depth)
1442 atomic_dec(&sdev->device_busy);
1447 * scsi_target_queue_ready: checks if there we can send commands to target
1448 * @sdev: scsi device on starget to check.
1450 static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1451 struct scsi_device *sdev)
1453 struct scsi_target *starget = scsi_target(sdev);
1456 if (starget->single_lun) {
1457 spin_lock_irq(shost->host_lock);
1458 if (starget->starget_sdev_user &&
1459 starget->starget_sdev_user != sdev) {
1460 spin_unlock_irq(shost->host_lock);
1463 starget->starget_sdev_user = sdev;
1464 spin_unlock_irq(shost->host_lock);
1467 if (starget->can_queue <= 0)
1470 busy = atomic_inc_return(&starget->target_busy) - 1;
1471 if (atomic_read(&starget->target_blocked) > 0) {
1476 * unblock after target_blocked iterates to zero
1478 if (atomic_dec_return(&starget->target_blocked) > 0)
1481 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1482 "unblocking target at zero depth\n"));
1485 if (busy >= starget->can_queue)
1491 spin_lock_irq(shost->host_lock);
1492 list_move_tail(&sdev->starved_entry, &shost->starved_list);
1493 spin_unlock_irq(shost->host_lock);
1495 if (starget->can_queue > 0)
1496 atomic_dec(&starget->target_busy);
1501 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1502 * return 0. We must end up running the queue again whenever 0 is
1503 * returned, else IO can hang.
1505 static inline int scsi_host_queue_ready(struct request_queue *q,
1506 struct Scsi_Host *shost,
1507 struct scsi_device *sdev)
1511 if (scsi_host_in_recovery(shost))
1514 busy = atomic_inc_return(&shost->host_busy) - 1;
1515 if (atomic_read(&shost->host_blocked) > 0) {
1520 * unblock after host_blocked iterates to zero
1522 if (atomic_dec_return(&shost->host_blocked) > 0)
1526 shost_printk(KERN_INFO, shost,
1527 "unblocking host at zero depth\n"));
1530 if (shost->can_queue > 0 && busy >= shost->can_queue)
1532 if (shost->host_self_blocked)
1535 /* We're OK to process the command, so we can't be starved */
1536 if (!list_empty(&sdev->starved_entry)) {
1537 spin_lock_irq(shost->host_lock);
1538 if (!list_empty(&sdev->starved_entry))
1539 list_del_init(&sdev->starved_entry);
1540 spin_unlock_irq(shost->host_lock);
1546 spin_lock_irq(shost->host_lock);
1547 if (list_empty(&sdev->starved_entry))
1548 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1549 spin_unlock_irq(shost->host_lock);
1551 scsi_dec_host_busy(shost);
1556 * Busy state exporting function for request stacking drivers.
1558 * For efficiency, no lock is taken to check the busy state of
1559 * shost/starget/sdev, since the returned value is not guaranteed and
1560 * may be changed after request stacking drivers call the function,
1561 * regardless of taking lock or not.
1563 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1564 * needs to return 'not busy'. Otherwise, request stacking drivers
1565 * may hold requests forever.
1567 static int scsi_lld_busy(struct request_queue *q)
1569 struct scsi_device *sdev = q->queuedata;
1570 struct Scsi_Host *shost;
1572 if (blk_queue_dying(q))
1578 * Ignore host/starget busy state.
1579 * Since block layer does not have a concept of fairness across
1580 * multiple queues, congestion of host/starget needs to be handled
1583 if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
1590 * Kill a request for a dead device
1592 static void scsi_kill_request(struct request *req, struct request_queue *q)
1594 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1595 struct scsi_device *sdev;
1596 struct scsi_target *starget;
1597 struct Scsi_Host *shost;
1599 blk_start_request(req);
1601 scmd_printk(KERN_INFO, cmd, "killing request\n");
1604 starget = scsi_target(sdev);
1606 scsi_init_cmd_errh(cmd);
1607 cmd->result = DID_NO_CONNECT << 16;
1608 atomic_inc(&cmd->device->iorequest_cnt);
1611 * SCSI request completion path will do scsi_device_unbusy(),
1612 * bump busy counts. To bump the counters, we need to dance
1613 * with the locks as normal issue path does.
1615 atomic_inc(&sdev->device_busy);
1616 atomic_inc(&shost->host_busy);
1617 if (starget->can_queue > 0)
1618 atomic_inc(&starget->target_busy);
1620 blk_complete_request(req);
1623 static void scsi_softirq_done(struct request *rq)
1625 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1626 unsigned long wait_for = (cmd->allowed + 1) * rq->timeout;
1629 INIT_LIST_HEAD(&cmd->eh_entry);
1631 atomic_inc(&cmd->device->iodone_cnt);
1633 atomic_inc(&cmd->device->ioerr_cnt);
1635 disposition = scsi_decide_disposition(cmd);
1636 if (disposition != SUCCESS &&
1637 time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
1638 sdev_printk(KERN_ERR, cmd->device,
1639 "timing out command, waited %lus\n",
1641 disposition = SUCCESS;
1644 scsi_log_completion(cmd, disposition);
1646 switch (disposition) {
1648 scsi_finish_command(cmd);
1651 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
1653 case ADD_TO_MLQUEUE:
1654 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1657 scsi_eh_scmd_add(cmd);
1663 * scsi_dispatch_command - Dispatch a command to the low-level driver.
1664 * @cmd: command block we are dispatching.
1666 * Return: nonzero return request was rejected and device's queue needs to be
1669 static int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
1671 struct Scsi_Host *host = cmd->device->host;
1674 atomic_inc(&cmd->device->iorequest_cnt);
1676 /* check if the device is still usable */
1677 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
1678 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
1679 * returns an immediate error upwards, and signals
1680 * that the device is no longer present */
1681 cmd->result = DID_NO_CONNECT << 16;
1685 /* Check to see if the scsi lld made this device blocked. */
1686 if (unlikely(scsi_device_blocked(cmd->device))) {
1688 * in blocked state, the command is just put back on
1689 * the device queue. The suspend state has already
1690 * blocked the queue so future requests should not
1691 * occur until the device transitions out of the
1694 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1695 "queuecommand : device blocked\n"));
1696 return SCSI_MLQUEUE_DEVICE_BUSY;
1699 /* Store the LUN value in cmnd, if needed. */
1700 if (cmd->device->lun_in_cdb)
1701 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
1702 (cmd->device->lun << 5 & 0xe0);
1707 * Before we queue this command, check if the command
1708 * length exceeds what the host adapter can handle.
1710 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
1711 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1712 "queuecommand : command too long. "
1713 "cdb_size=%d host->max_cmd_len=%d\n",
1714 cmd->cmd_len, cmd->device->host->max_cmd_len));
1715 cmd->result = (DID_ABORT << 16);
1719 if (unlikely(host->shost_state == SHOST_DEL)) {
1720 cmd->result = (DID_NO_CONNECT << 16);
1725 trace_scsi_dispatch_cmd_start(cmd);
1726 rtn = host->hostt->queuecommand(host, cmd);
1728 trace_scsi_dispatch_cmd_error(cmd, rtn);
1729 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
1730 rtn != SCSI_MLQUEUE_TARGET_BUSY)
1731 rtn = SCSI_MLQUEUE_HOST_BUSY;
1733 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1734 "queuecommand : request rejected\n"));
1739 cmd->scsi_done(cmd);
1744 * scsi_done - Invoke completion on finished SCSI command.
1745 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
1746 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
1748 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
1749 * which regains ownership of the SCSI command (de facto) from a LLDD, and
1750 * calls blk_complete_request() for further processing.
1752 * This function is interrupt context safe.
1754 static void scsi_done(struct scsi_cmnd *cmd)
1756 trace_scsi_dispatch_cmd_done(cmd);
1757 blk_complete_request(cmd->request);
1761 * Function: scsi_request_fn()
1763 * Purpose: Main strategy routine for SCSI.
1765 * Arguments: q - Pointer to actual queue.
1769 * Lock status: request queue lock assumed to be held when called.
1771 * Note: See sd_zbc.c sd_zbc_write_lock_zone() for write order
1772 * protection for ZBC disks.
1774 static void scsi_request_fn(struct request_queue *q)
1775 __releases(q->queue_lock)
1776 __acquires(q->queue_lock)
1778 struct scsi_device *sdev = q->queuedata;
1779 struct Scsi_Host *shost;
1780 struct scsi_cmnd *cmd;
1781 struct request *req;
1784 * To start with, we keep looping until the queue is empty, or until
1785 * the host is no longer able to accept any more requests.
1791 * get next queueable request. We do this early to make sure
1792 * that the request is fully prepared even if we cannot
1795 req = blk_peek_request(q);
1799 if (unlikely(!scsi_device_online(sdev))) {
1800 sdev_printk(KERN_ERR, sdev,
1801 "rejecting I/O to offline device\n");
1802 scsi_kill_request(req, q);
1806 if (!scsi_dev_queue_ready(q, sdev))
1810 * Remove the request from the request list.
1812 if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req)))
1813 blk_start_request(req);
1815 spin_unlock_irq(q->queue_lock);
1816 cmd = blk_mq_rq_to_pdu(req);
1817 if (cmd != req->special) {
1818 printk(KERN_CRIT "impossible request in %s.\n"
1819 "please mail a stack trace to "
1820 "linux-scsi@vger.kernel.org\n",
1822 blk_dump_rq_flags(req, "foo");
1827 * We hit this when the driver is using a host wide
1828 * tag map. For device level tag maps the queue_depth check
1829 * in the device ready fn would prevent us from trying
1830 * to allocate a tag. Since the map is a shared host resource
1831 * we add the dev to the starved list so it eventually gets
1832 * a run when a tag is freed.
1834 if (blk_queue_tagged(q) && !(req->rq_flags & RQF_QUEUED)) {
1835 spin_lock_irq(shost->host_lock);
1836 if (list_empty(&sdev->starved_entry))
1837 list_add_tail(&sdev->starved_entry,
1838 &shost->starved_list);
1839 spin_unlock_irq(shost->host_lock);
1843 if (!scsi_target_queue_ready(shost, sdev))
1846 if (!scsi_host_queue_ready(q, shost, sdev))
1847 goto host_not_ready;
1849 if (sdev->simple_tags)
1850 cmd->flags |= SCMD_TAGGED;
1852 cmd->flags &= ~SCMD_TAGGED;
1855 * Finally, initialize any error handling parameters, and set up
1856 * the timers for timeouts.
1858 scsi_init_cmd_errh(cmd);
1861 * Dispatch the command to the low-level driver.
1863 cmd->scsi_done = scsi_done;
1864 rtn = scsi_dispatch_cmd(cmd);
1866 scsi_queue_insert(cmd, rtn);
1867 spin_lock_irq(q->queue_lock);
1870 spin_lock_irq(q->queue_lock);
1876 if (scsi_target(sdev)->can_queue > 0)
1877 atomic_dec(&scsi_target(sdev)->target_busy);
1880 * lock q, handle tag, requeue req, and decrement device_busy. We
1881 * must return with queue_lock held.
1883 * Decrementing device_busy without checking it is OK, as all such
1884 * cases (host limits or settings) should run the queue at some
1887 spin_lock_irq(q->queue_lock);
1888 blk_requeue_request(q, req);
1889 atomic_dec(&sdev->device_busy);
1891 if (!atomic_read(&sdev->device_busy) && !scsi_device_blocked(sdev))
1892 blk_delay_queue(q, SCSI_QUEUE_DELAY);
1895 static inline blk_status_t prep_to_mq(int ret)
1901 return BLK_STS_RESOURCE;
1903 return BLK_STS_IOERR;
1907 /* Size in bytes of the sg-list stored in the scsi-mq command-private data. */
1908 static unsigned int scsi_mq_sgl_size(struct Scsi_Host *shost)
1910 return min_t(unsigned int, shost->sg_tablesize, SG_CHUNK_SIZE) *
1911 sizeof(struct scatterlist);
1914 static int scsi_mq_prep_fn(struct request *req)
1916 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1917 struct scsi_device *sdev = req->q->queuedata;
1918 struct Scsi_Host *shost = sdev->host;
1919 struct scatterlist *sg;
1921 scsi_init_command(sdev, cmd);
1927 cmd->tag = req->tag;
1928 cmd->prot_op = SCSI_PROT_NORMAL;
1930 sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
1931 cmd->sdb.table.sgl = sg;
1933 if (scsi_host_get_prot(shost)) {
1934 memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer));
1936 cmd->prot_sdb->table.sgl =
1937 (struct scatterlist *)(cmd->prot_sdb + 1);
1940 if (blk_bidi_rq(req)) {
1941 struct request *next_rq = req->next_rq;
1942 struct scsi_data_buffer *bidi_sdb = blk_mq_rq_to_pdu(next_rq);
1944 memset(bidi_sdb, 0, sizeof(struct scsi_data_buffer));
1945 bidi_sdb->table.sgl =
1946 (struct scatterlist *)(bidi_sdb + 1);
1948 next_rq->special = bidi_sdb;
1951 blk_mq_start_request(req);
1953 return scsi_setup_cmnd(sdev, req);
1956 static void scsi_mq_done(struct scsi_cmnd *cmd)
1958 trace_scsi_dispatch_cmd_done(cmd);
1959 blk_mq_complete_request(cmd->request);
1962 static void scsi_mq_put_budget(struct blk_mq_hw_ctx *hctx)
1964 struct request_queue *q = hctx->queue;
1965 struct scsi_device *sdev = q->queuedata;
1967 atomic_dec(&sdev->device_busy);
1968 put_device(&sdev->sdev_gendev);
1971 static bool scsi_mq_get_budget(struct blk_mq_hw_ctx *hctx)
1973 struct request_queue *q = hctx->queue;
1974 struct scsi_device *sdev = q->queuedata;
1976 if (!get_device(&sdev->sdev_gendev))
1978 if (!scsi_dev_queue_ready(q, sdev))
1979 goto out_put_device;
1984 put_device(&sdev->sdev_gendev);
1989 static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
1990 const struct blk_mq_queue_data *bd)
1992 struct request *req = bd->rq;
1993 struct request_queue *q = req->q;
1994 struct scsi_device *sdev = q->queuedata;
1995 struct Scsi_Host *shost = sdev->host;
1996 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
2000 ret = prep_to_mq(scsi_prep_state_check(sdev, req));
2001 if (ret != BLK_STS_OK)
2002 goto out_put_budget;
2004 ret = BLK_STS_RESOURCE;
2005 if (!scsi_target_queue_ready(shost, sdev))
2006 goto out_put_budget;
2007 if (!scsi_host_queue_ready(q, shost, sdev))
2008 goto out_dec_target_busy;
2010 if (!(req->rq_flags & RQF_DONTPREP)) {
2011 ret = prep_to_mq(scsi_mq_prep_fn(req));
2012 if (ret != BLK_STS_OK)
2013 goto out_dec_host_busy;
2014 req->rq_flags |= RQF_DONTPREP;
2016 blk_mq_start_request(req);
2019 if (sdev->simple_tags)
2020 cmd->flags |= SCMD_TAGGED;
2022 cmd->flags &= ~SCMD_TAGGED;
2024 scsi_init_cmd_errh(cmd);
2025 cmd->scsi_done = scsi_mq_done;
2027 reason = scsi_dispatch_cmd(cmd);
2029 scsi_set_blocked(cmd, reason);
2030 ret = BLK_STS_RESOURCE;
2031 goto out_dec_host_busy;
2037 scsi_dec_host_busy(shost);
2038 out_dec_target_busy:
2039 if (scsi_target(sdev)->can_queue > 0)
2040 atomic_dec(&scsi_target(sdev)->target_busy);
2042 scsi_mq_put_budget(hctx);
2046 case BLK_STS_RESOURCE:
2047 if (atomic_read(&sdev->device_busy) == 0 &&
2048 !scsi_device_blocked(sdev))
2049 blk_mq_delay_run_hw_queue(hctx, SCSI_QUEUE_DELAY);
2053 * Make sure to release all allocated ressources when
2054 * we hit an error, as we will never see this command
2057 if (req->rq_flags & RQF_DONTPREP)
2058 scsi_mq_uninit_cmd(cmd);
2064 static enum blk_eh_timer_return scsi_timeout(struct request *req,
2068 return BLK_EH_RESET_TIMER;
2069 return scsi_times_out(req);
2072 static int scsi_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
2073 unsigned int hctx_idx, unsigned int numa_node)
2075 struct Scsi_Host *shost = set->driver_data;
2076 const bool unchecked_isa_dma = shost->unchecked_isa_dma;
2077 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
2078 struct scatterlist *sg;
2080 if (unchecked_isa_dma)
2081 cmd->flags |= SCMD_UNCHECKED_ISA_DMA;
2082 cmd->sense_buffer = scsi_alloc_sense_buffer(unchecked_isa_dma,
2083 GFP_KERNEL, numa_node);
2084 if (!cmd->sense_buffer)
2086 cmd->req.sense = cmd->sense_buffer;
2088 if (scsi_host_get_prot(shost)) {
2089 sg = (void *)cmd + sizeof(struct scsi_cmnd) +
2090 shost->hostt->cmd_size;
2091 cmd->prot_sdb = (void *)sg + scsi_mq_sgl_size(shost);
2097 static void scsi_mq_exit_request(struct blk_mq_tag_set *set, struct request *rq,
2098 unsigned int hctx_idx)
2100 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
2102 scsi_free_sense_buffer(cmd->flags & SCMD_UNCHECKED_ISA_DMA,
2106 static int scsi_map_queues(struct blk_mq_tag_set *set)
2108 struct Scsi_Host *shost = container_of(set, struct Scsi_Host, tag_set);
2110 if (shost->hostt->map_queues)
2111 return shost->hostt->map_queues(shost);
2112 return blk_mq_map_queues(set);
2115 static u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost)
2117 struct device *host_dev;
2118 u64 bounce_limit = 0xffffffff;
2120 if (shost->unchecked_isa_dma)
2121 return BLK_BOUNCE_ISA;
2123 * Platforms with virtual-DMA translation
2124 * hardware have no practical limit.
2126 if (!PCI_DMA_BUS_IS_PHYS)
2127 return BLK_BOUNCE_ANY;
2129 host_dev = scsi_get_device(shost);
2130 if (host_dev && host_dev->dma_mask)
2131 bounce_limit = (u64)dma_max_pfn(host_dev) << PAGE_SHIFT;
2133 return bounce_limit;
2136 void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
2138 struct device *dev = shost->dma_dev;
2140 queue_flag_set_unlocked(QUEUE_FLAG_SCSI_PASSTHROUGH, q);
2143 * this limit is imposed by hardware restrictions
2145 blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
2148 if (scsi_host_prot_dma(shost)) {
2149 shost->sg_prot_tablesize =
2150 min_not_zero(shost->sg_prot_tablesize,
2151 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
2152 BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
2153 blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
2156 blk_queue_max_hw_sectors(q, shost->max_sectors);
2157 blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost));
2158 blk_queue_segment_boundary(q, shost->dma_boundary);
2159 dma_set_seg_boundary(dev, shost->dma_boundary);
2161 blk_queue_max_segment_size(q, dma_get_max_seg_size(dev));
2163 if (!shost->use_clustering)
2164 q->limits.cluster = 0;
2167 * set a reasonable default alignment on word boundaries: the
2168 * host and device may alter it using
2169 * blk_queue_update_dma_alignment() later.
2171 blk_queue_dma_alignment(q, 0x03);
2173 EXPORT_SYMBOL_GPL(__scsi_init_queue);
2175 static int scsi_old_init_rq(struct request_queue *q, struct request *rq,
2178 struct Scsi_Host *shost = q->rq_alloc_data;
2179 const bool unchecked_isa_dma = shost->unchecked_isa_dma;
2180 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
2182 memset(cmd, 0, sizeof(*cmd));
2184 if (unchecked_isa_dma)
2185 cmd->flags |= SCMD_UNCHECKED_ISA_DMA;
2186 cmd->sense_buffer = scsi_alloc_sense_buffer(unchecked_isa_dma, gfp,
2188 if (!cmd->sense_buffer)
2190 cmd->req.sense = cmd->sense_buffer;
2192 if (scsi_host_get_prot(shost) >= SHOST_DIX_TYPE0_PROTECTION) {
2193 cmd->prot_sdb = kmem_cache_zalloc(scsi_sdb_cache, gfp);
2195 goto fail_free_sense;
2201 scsi_free_sense_buffer(unchecked_isa_dma, cmd->sense_buffer);
2206 static void scsi_old_exit_rq(struct request_queue *q, struct request *rq)
2208 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
2211 kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb);
2212 scsi_free_sense_buffer(cmd->flags & SCMD_UNCHECKED_ISA_DMA,
2216 struct request_queue *scsi_old_alloc_queue(struct scsi_device *sdev)
2218 struct Scsi_Host *shost = sdev->host;
2219 struct request_queue *q;
2221 q = blk_alloc_queue_node(GFP_KERNEL, NUMA_NO_NODE);
2224 q->cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
2225 q->rq_alloc_data = shost;
2226 q->request_fn = scsi_request_fn;
2227 q->init_rq_fn = scsi_old_init_rq;
2228 q->exit_rq_fn = scsi_old_exit_rq;
2229 q->initialize_rq_fn = scsi_initialize_rq;
2231 if (blk_init_allocated_queue(q) < 0) {
2232 blk_cleanup_queue(q);
2236 __scsi_init_queue(shost, q);
2237 blk_queue_prep_rq(q, scsi_prep_fn);
2238 blk_queue_unprep_rq(q, scsi_unprep_fn);
2239 blk_queue_softirq_done(q, scsi_softirq_done);
2240 blk_queue_rq_timed_out(q, scsi_times_out);
2241 blk_queue_lld_busy(q, scsi_lld_busy);
2245 static const struct blk_mq_ops scsi_mq_ops = {
2246 .get_budget = scsi_mq_get_budget,
2247 .put_budget = scsi_mq_put_budget,
2248 .queue_rq = scsi_queue_rq,
2249 .complete = scsi_softirq_done,
2250 .timeout = scsi_timeout,
2251 #ifdef CONFIG_BLK_DEBUG_FS
2252 .show_rq = scsi_show_rq,
2254 .init_request = scsi_mq_init_request,
2255 .exit_request = scsi_mq_exit_request,
2256 .initialize_rq_fn = scsi_initialize_rq,
2257 .map_queues = scsi_map_queues,
2260 struct request_queue *scsi_mq_alloc_queue(struct scsi_device *sdev)
2262 sdev->request_queue = blk_mq_init_queue(&sdev->host->tag_set);
2263 if (IS_ERR(sdev->request_queue))
2266 sdev->request_queue->queuedata = sdev;
2267 __scsi_init_queue(sdev->host, sdev->request_queue);
2268 return sdev->request_queue;
2271 int scsi_mq_setup_tags(struct Scsi_Host *shost)
2273 unsigned int cmd_size, sgl_size;
2275 sgl_size = scsi_mq_sgl_size(shost);
2276 cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size;
2277 if (scsi_host_get_prot(shost))
2278 cmd_size += sizeof(struct scsi_data_buffer) + sgl_size;
2280 memset(&shost->tag_set, 0, sizeof(shost->tag_set));
2281 shost->tag_set.ops = &scsi_mq_ops;
2282 shost->tag_set.nr_hw_queues = shost->nr_hw_queues ? : 1;
2283 shost->tag_set.queue_depth = shost->can_queue;
2284 shost->tag_set.cmd_size = cmd_size;
2285 shost->tag_set.numa_node = NUMA_NO_NODE;
2286 shost->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
2287 shost->tag_set.flags |=
2288 BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
2289 shost->tag_set.driver_data = shost;
2291 return blk_mq_alloc_tag_set(&shost->tag_set);
2294 void scsi_mq_destroy_tags(struct Scsi_Host *shost)
2296 blk_mq_free_tag_set(&shost->tag_set);
2300 * scsi_device_from_queue - return sdev associated with a request_queue
2301 * @q: The request queue to return the sdev from
2303 * Return the sdev associated with a request queue or NULL if the
2304 * request_queue does not reference a SCSI device.
2306 struct scsi_device *scsi_device_from_queue(struct request_queue *q)
2308 struct scsi_device *sdev = NULL;
2311 if (q->mq_ops == &scsi_mq_ops)
2312 sdev = q->queuedata;
2313 } else if (q->request_fn == scsi_request_fn)
2314 sdev = q->queuedata;
2315 if (!sdev || !get_device(&sdev->sdev_gendev))
2320 EXPORT_SYMBOL_GPL(scsi_device_from_queue);
2323 * Function: scsi_block_requests()
2325 * Purpose: Utility function used by low-level drivers to prevent further
2326 * commands from being queued to the device.
2328 * Arguments: shost - Host in question
2332 * Lock status: No locks are assumed held.
2334 * Notes: There is no timer nor any other means by which the requests
2335 * get unblocked other than the low-level driver calling
2336 * scsi_unblock_requests().
2338 void scsi_block_requests(struct Scsi_Host *shost)
2340 shost->host_self_blocked = 1;
2342 EXPORT_SYMBOL(scsi_block_requests);
2345 * Function: scsi_unblock_requests()
2347 * Purpose: Utility function used by low-level drivers to allow further
2348 * commands from being queued to the device.
2350 * Arguments: shost - Host in question
2354 * Lock status: No locks are assumed held.
2356 * Notes: There is no timer nor any other means by which the requests
2357 * get unblocked other than the low-level driver calling
2358 * scsi_unblock_requests().
2360 * This is done as an API function so that changes to the
2361 * internals of the scsi mid-layer won't require wholesale
2362 * changes to drivers that use this feature.
2364 void scsi_unblock_requests(struct Scsi_Host *shost)
2366 shost->host_self_blocked = 0;
2367 scsi_run_host_queues(shost);
2369 EXPORT_SYMBOL(scsi_unblock_requests);
2371 int __init scsi_init_queue(void)
2373 scsi_sdb_cache = kmem_cache_create("scsi_data_buffer",
2374 sizeof(struct scsi_data_buffer),
2376 if (!scsi_sdb_cache) {
2377 printk(KERN_ERR "SCSI: can't init scsi sdb cache\n");
2384 void scsi_exit_queue(void)
2386 kmem_cache_destroy(scsi_sense_cache);
2387 kmem_cache_destroy(scsi_sense_isadma_cache);
2388 kmem_cache_destroy(scsi_sdb_cache);
2392 * scsi_mode_select - issue a mode select
2393 * @sdev: SCSI device to be queried
2394 * @pf: Page format bit (1 == standard, 0 == vendor specific)
2395 * @sp: Save page bit (0 == don't save, 1 == save)
2396 * @modepage: mode page being requested
2397 * @buffer: request buffer (may not be smaller than eight bytes)
2398 * @len: length of request buffer.
2399 * @timeout: command timeout
2400 * @retries: number of retries before failing
2401 * @data: returns a structure abstracting the mode header data
2402 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2403 * must be SCSI_SENSE_BUFFERSIZE big.
2405 * Returns zero if successful; negative error number or scsi
2410 scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
2411 unsigned char *buffer, int len, int timeout, int retries,
2412 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2414 unsigned char cmd[10];
2415 unsigned char *real_buffer;
2418 memset(cmd, 0, sizeof(cmd));
2419 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
2421 if (sdev->use_10_for_ms) {
2424 real_buffer = kmalloc(8 + len, GFP_KERNEL);
2427 memcpy(real_buffer + 8, buffer, len);
2431 real_buffer[2] = data->medium_type;
2432 real_buffer[3] = data->device_specific;
2433 real_buffer[4] = data->longlba ? 0x01 : 0;
2435 real_buffer[6] = data->block_descriptor_length >> 8;
2436 real_buffer[7] = data->block_descriptor_length;
2438 cmd[0] = MODE_SELECT_10;
2442 if (len > 255 || data->block_descriptor_length > 255 ||
2446 real_buffer = kmalloc(4 + len, GFP_KERNEL);
2449 memcpy(real_buffer + 4, buffer, len);
2452 real_buffer[1] = data->medium_type;
2453 real_buffer[2] = data->device_specific;
2454 real_buffer[3] = data->block_descriptor_length;
2457 cmd[0] = MODE_SELECT;
2461 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
2462 sshdr, timeout, retries, NULL);
2466 EXPORT_SYMBOL_GPL(scsi_mode_select);
2469 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
2470 * @sdev: SCSI device to be queried
2471 * @dbd: set if mode sense will allow block descriptors to be returned
2472 * @modepage: mode page being requested
2473 * @buffer: request buffer (may not be smaller than eight bytes)
2474 * @len: length of request buffer.
2475 * @timeout: command timeout
2476 * @retries: number of retries before failing
2477 * @data: returns a structure abstracting the mode header data
2478 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2479 * must be SCSI_SENSE_BUFFERSIZE big.
2481 * Returns zero if unsuccessful, or the header offset (either 4
2482 * or 8 depending on whether a six or ten byte command was
2483 * issued) if successful.
2486 scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
2487 unsigned char *buffer, int len, int timeout, int retries,
2488 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2490 unsigned char cmd[12];
2493 int result, retry_count = retries;
2494 struct scsi_sense_hdr my_sshdr;
2496 memset(data, 0, sizeof(*data));
2497 memset(&cmd[0], 0, 12);
2498 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
2501 /* caller might not be interested in sense, but we need it */
2506 use_10_for_ms = sdev->use_10_for_ms;
2508 if (use_10_for_ms) {
2512 cmd[0] = MODE_SENSE_10;
2519 cmd[0] = MODE_SENSE;
2524 memset(buffer, 0, len);
2526 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
2527 sshdr, timeout, retries, NULL);
2529 /* This code looks awful: what it's doing is making sure an
2530 * ILLEGAL REQUEST sense return identifies the actual command
2531 * byte as the problem. MODE_SENSE commands can return
2532 * ILLEGAL REQUEST if the code page isn't supported */
2534 if (use_10_for_ms && !scsi_status_is_good(result) &&
2535 (driver_byte(result) & DRIVER_SENSE)) {
2536 if (scsi_sense_valid(sshdr)) {
2537 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
2538 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
2540 * Invalid command operation code
2542 sdev->use_10_for_ms = 0;
2548 if(scsi_status_is_good(result)) {
2549 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
2550 (modepage == 6 || modepage == 8))) {
2551 /* Initio breakage? */
2554 data->medium_type = 0;
2555 data->device_specific = 0;
2557 data->block_descriptor_length = 0;
2558 } else if(use_10_for_ms) {
2559 data->length = buffer[0]*256 + buffer[1] + 2;
2560 data->medium_type = buffer[2];
2561 data->device_specific = buffer[3];
2562 data->longlba = buffer[4] & 0x01;
2563 data->block_descriptor_length = buffer[6]*256
2566 data->length = buffer[0] + 1;
2567 data->medium_type = buffer[1];
2568 data->device_specific = buffer[2];
2569 data->block_descriptor_length = buffer[3];
2571 data->header_length = header_length;
2572 } else if ((status_byte(result) == CHECK_CONDITION) &&
2573 scsi_sense_valid(sshdr) &&
2574 sshdr->sense_key == UNIT_ATTENTION && retry_count) {
2581 EXPORT_SYMBOL(scsi_mode_sense);
2584 * scsi_test_unit_ready - test if unit is ready
2585 * @sdev: scsi device to change the state of.
2586 * @timeout: command timeout
2587 * @retries: number of retries before failing
2588 * @sshdr: outpout pointer for decoded sense information.
2590 * Returns zero if unsuccessful or an error if TUR failed. For
2591 * removable media, UNIT_ATTENTION sets ->changed flag.
2594 scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2595 struct scsi_sense_hdr *sshdr)
2598 TEST_UNIT_READY, 0, 0, 0, 0, 0,
2602 /* try to eat the UNIT_ATTENTION if there are enough retries */
2604 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
2605 timeout, retries, NULL);
2606 if (sdev->removable && scsi_sense_valid(sshdr) &&
2607 sshdr->sense_key == UNIT_ATTENTION)
2609 } while (scsi_sense_valid(sshdr) &&
2610 sshdr->sense_key == UNIT_ATTENTION && --retries);
2614 EXPORT_SYMBOL(scsi_test_unit_ready);
2617 * scsi_device_set_state - Take the given device through the device state model.
2618 * @sdev: scsi device to change the state of.
2619 * @state: state to change to.
2621 * Returns zero if successful or an error if the requested
2622 * transition is illegal.
2625 scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2627 enum scsi_device_state oldstate = sdev->sdev_state;
2629 if (state == oldstate)
2635 case SDEV_CREATED_BLOCK:
2646 case SDEV_TRANSPORT_OFFLINE:
2659 case SDEV_TRANSPORT_OFFLINE:
2667 case SDEV_TRANSPORT_OFFLINE:
2682 case SDEV_CREATED_BLOCK:
2689 case SDEV_CREATED_BLOCK:
2704 case SDEV_TRANSPORT_OFFLINE:
2716 case SDEV_TRANSPORT_OFFLINE:
2719 case SDEV_CREATED_BLOCK:
2727 sdev->sdev_state = state;
2731 SCSI_LOG_ERROR_RECOVERY(1,
2732 sdev_printk(KERN_ERR, sdev,
2733 "Illegal state transition %s->%s",
2734 scsi_device_state_name(oldstate),
2735 scsi_device_state_name(state))
2739 EXPORT_SYMBOL(scsi_device_set_state);
2742 * sdev_evt_emit - emit a single SCSI device uevent
2743 * @sdev: associated SCSI device
2744 * @evt: event to emit
2746 * Send a single uevent (scsi_event) to the associated scsi_device.
2748 static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2753 switch (evt->evt_type) {
2754 case SDEV_EVT_MEDIA_CHANGE:
2755 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2757 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2758 scsi_rescan_device(&sdev->sdev_gendev);
2759 envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2761 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2762 envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2764 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2765 envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2767 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2768 envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2770 case SDEV_EVT_LUN_CHANGE_REPORTED:
2771 envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2773 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2774 envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
2776 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2777 envp[idx++] = "SDEV_UA=POWER_ON_RESET_OCCURRED";
2786 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2790 * sdev_evt_thread - send a uevent for each scsi event
2791 * @work: work struct for scsi_device
2793 * Dispatch queued events to their associated scsi_device kobjects
2796 void scsi_evt_thread(struct work_struct *work)
2798 struct scsi_device *sdev;
2799 enum scsi_device_event evt_type;
2800 LIST_HEAD(event_list);
2802 sdev = container_of(work, struct scsi_device, event_work);
2804 for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
2805 if (test_and_clear_bit(evt_type, sdev->pending_events))
2806 sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
2809 struct scsi_event *evt;
2810 struct list_head *this, *tmp;
2811 unsigned long flags;
2813 spin_lock_irqsave(&sdev->list_lock, flags);
2814 list_splice_init(&sdev->event_list, &event_list);
2815 spin_unlock_irqrestore(&sdev->list_lock, flags);
2817 if (list_empty(&event_list))
2820 list_for_each_safe(this, tmp, &event_list) {
2821 evt = list_entry(this, struct scsi_event, node);
2822 list_del(&evt->node);
2823 scsi_evt_emit(sdev, evt);
2830 * sdev_evt_send - send asserted event to uevent thread
2831 * @sdev: scsi_device event occurred on
2832 * @evt: event to send
2834 * Assert scsi device event asynchronously.
2836 void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2838 unsigned long flags;
2841 /* FIXME: currently this check eliminates all media change events
2842 * for polled devices. Need to update to discriminate between AN
2843 * and polled events */
2844 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2850 spin_lock_irqsave(&sdev->list_lock, flags);
2851 list_add_tail(&evt->node, &sdev->event_list);
2852 schedule_work(&sdev->event_work);
2853 spin_unlock_irqrestore(&sdev->list_lock, flags);
2855 EXPORT_SYMBOL_GPL(sdev_evt_send);
2858 * sdev_evt_alloc - allocate a new scsi event
2859 * @evt_type: type of event to allocate
2860 * @gfpflags: GFP flags for allocation
2862 * Allocates and returns a new scsi_event.
2864 struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2867 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2871 evt->evt_type = evt_type;
2872 INIT_LIST_HEAD(&evt->node);
2874 /* evt_type-specific initialization, if any */
2876 case SDEV_EVT_MEDIA_CHANGE:
2877 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2878 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2879 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2880 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2881 case SDEV_EVT_LUN_CHANGE_REPORTED:
2882 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2883 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2891 EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2894 * sdev_evt_send_simple - send asserted event to uevent thread
2895 * @sdev: scsi_device event occurred on
2896 * @evt_type: type of event to send
2897 * @gfpflags: GFP flags for allocation
2899 * Assert scsi device event asynchronously, given an event type.
2901 void sdev_evt_send_simple(struct scsi_device *sdev,
2902 enum scsi_device_event evt_type, gfp_t gfpflags)
2904 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2906 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2911 sdev_evt_send(sdev, evt);
2913 EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2916 * scsi_request_fn_active() - number of kernel threads inside scsi_request_fn()
2917 * @sdev: SCSI device to count the number of scsi_request_fn() callers for.
2919 static int scsi_request_fn_active(struct scsi_device *sdev)
2921 struct request_queue *q = sdev->request_queue;
2922 int request_fn_active;
2924 WARN_ON_ONCE(sdev->host->use_blk_mq);
2926 spin_lock_irq(q->queue_lock);
2927 request_fn_active = q->request_fn_active;
2928 spin_unlock_irq(q->queue_lock);
2930 return request_fn_active;
2934 * scsi_wait_for_queuecommand() - wait for ongoing queuecommand() calls
2935 * @sdev: SCSI device pointer.
2937 * Wait until the ongoing shost->hostt->queuecommand() calls that are
2938 * invoked from scsi_request_fn() have finished.
2940 static void scsi_wait_for_queuecommand(struct scsi_device *sdev)
2942 WARN_ON_ONCE(sdev->host->use_blk_mq);
2944 while (scsi_request_fn_active(sdev))
2949 * scsi_device_quiesce - Block user issued commands.
2950 * @sdev: scsi device to quiesce.
2952 * This works by trying to transition to the SDEV_QUIESCE state
2953 * (which must be a legal transition). When the device is in this
2954 * state, only special requests will be accepted, all others will
2955 * be deferred. Since special requests may also be requeued requests,
2956 * a successful return doesn't guarantee the device will be
2957 * totally quiescent.
2959 * Must be called with user context, may sleep.
2961 * Returns zero if unsuccessful or an error if not.
2964 scsi_device_quiesce(struct scsi_device *sdev)
2966 struct request_queue *q = sdev->request_queue;
2970 * It is allowed to call scsi_device_quiesce() multiple times from
2971 * the same context but concurrent scsi_device_quiesce() calls are
2974 WARN_ON_ONCE(sdev->quiesced_by && sdev->quiesced_by != current);
2976 blk_set_preempt_only(q);
2978 blk_mq_freeze_queue(q);
2980 * Ensure that the effect of blk_set_preempt_only() will be visible
2981 * for percpu_ref_tryget() callers that occur after the queue
2982 * unfreeze even if the queue was already frozen before this function
2983 * was called. See also https://lwn.net/Articles/573497/.
2986 blk_mq_unfreeze_queue(q);
2988 mutex_lock(&sdev->state_mutex);
2989 err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2991 sdev->quiesced_by = current;
2993 blk_clear_preempt_only(q);
2994 mutex_unlock(&sdev->state_mutex);
2998 EXPORT_SYMBOL(scsi_device_quiesce);
3001 * scsi_device_resume - Restart user issued commands to a quiesced device.
3002 * @sdev: scsi device to resume.
3004 * Moves the device from quiesced back to running and restarts the
3007 * Must be called with user context, may sleep.
3009 void scsi_device_resume(struct scsi_device *sdev)
3011 /* check if the device state was mutated prior to resume, and if
3012 * so assume the state is being managed elsewhere (for example
3013 * device deleted during suspend)
3015 mutex_lock(&sdev->state_mutex);
3016 WARN_ON_ONCE(!sdev->quiesced_by);
3017 sdev->quiesced_by = NULL;
3018 blk_clear_preempt_only(sdev->request_queue);
3019 if (sdev->sdev_state == SDEV_QUIESCE)
3020 scsi_device_set_state(sdev, SDEV_RUNNING);
3021 mutex_unlock(&sdev->state_mutex);
3023 EXPORT_SYMBOL(scsi_device_resume);
3026 device_quiesce_fn(struct scsi_device *sdev, void *data)
3028 scsi_device_quiesce(sdev);
3032 scsi_target_quiesce(struct scsi_target *starget)
3034 starget_for_each_device(starget, NULL, device_quiesce_fn);
3036 EXPORT_SYMBOL(scsi_target_quiesce);
3039 device_resume_fn(struct scsi_device *sdev, void *data)
3041 scsi_device_resume(sdev);
3045 scsi_target_resume(struct scsi_target *starget)
3047 starget_for_each_device(starget, NULL, device_resume_fn);
3049 EXPORT_SYMBOL(scsi_target_resume);
3052 * scsi_internal_device_block_nowait - try to transition to the SDEV_BLOCK state
3053 * @sdev: device to block
3055 * Pause SCSI command processing on the specified device. Does not sleep.
3057 * Returns zero if successful or a negative error code upon failure.
3060 * This routine transitions the device to the SDEV_BLOCK state (which must be
3061 * a legal transition). When the device is in this state, command processing
3062 * is paused until the device leaves the SDEV_BLOCK state. See also
3063 * scsi_internal_device_unblock_nowait().
3065 int scsi_internal_device_block_nowait(struct scsi_device *sdev)
3067 struct request_queue *q = sdev->request_queue;
3068 unsigned long flags;
3071 err = scsi_device_set_state(sdev, SDEV_BLOCK);
3073 err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
3080 * The device has transitioned to SDEV_BLOCK. Stop the
3081 * block layer from calling the midlayer with this device's
3085 blk_mq_quiesce_queue_nowait(q);
3087 spin_lock_irqsave(q->queue_lock, flags);
3089 spin_unlock_irqrestore(q->queue_lock, flags);
3094 EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait);
3097 * scsi_internal_device_block - try to transition to the SDEV_BLOCK state
3098 * @sdev: device to block
3100 * Pause SCSI command processing on the specified device and wait until all
3101 * ongoing scsi_request_fn() / scsi_queue_rq() calls have finished. May sleep.
3103 * Returns zero if successful or a negative error code upon failure.
3106 * This routine transitions the device to the SDEV_BLOCK state (which must be
3107 * a legal transition). When the device is in this state, command processing
3108 * is paused until the device leaves the SDEV_BLOCK state. See also
3109 * scsi_internal_device_unblock().
3111 * To do: avoid that scsi_send_eh_cmnd() calls queuecommand() after
3112 * scsi_internal_device_block() has blocked a SCSI device and also
3113 * remove the rport mutex lock and unlock calls from srp_queuecommand().
3115 static int scsi_internal_device_block(struct scsi_device *sdev)
3117 struct request_queue *q = sdev->request_queue;
3120 mutex_lock(&sdev->state_mutex);
3121 err = scsi_internal_device_block_nowait(sdev);
3124 blk_mq_quiesce_queue(q);
3126 scsi_wait_for_queuecommand(sdev);
3128 mutex_unlock(&sdev->state_mutex);
3133 void scsi_start_queue(struct scsi_device *sdev)
3135 struct request_queue *q = sdev->request_queue;
3136 unsigned long flags;
3139 blk_mq_unquiesce_queue(q);
3141 spin_lock_irqsave(q->queue_lock, flags);
3143 spin_unlock_irqrestore(q->queue_lock, flags);
3148 * scsi_internal_device_unblock_nowait - resume a device after a block request
3149 * @sdev: device to resume
3150 * @new_state: state to set the device to after unblocking
3152 * Restart the device queue for a previously suspended SCSI device. Does not
3155 * Returns zero if successful or a negative error code upon failure.
3158 * This routine transitions the device to the SDEV_RUNNING state or to one of
3159 * the offline states (which must be a legal transition) allowing the midlayer
3160 * to goose the queue for this device.
3162 int scsi_internal_device_unblock_nowait(struct scsi_device *sdev,
3163 enum scsi_device_state new_state)
3166 * Try to transition the scsi device to SDEV_RUNNING or one of the
3167 * offlined states and goose the device queue if successful.
3169 switch (sdev->sdev_state) {
3171 case SDEV_TRANSPORT_OFFLINE:
3172 sdev->sdev_state = new_state;
3174 case SDEV_CREATED_BLOCK:
3175 if (new_state == SDEV_TRANSPORT_OFFLINE ||
3176 new_state == SDEV_OFFLINE)
3177 sdev->sdev_state = new_state;
3179 sdev->sdev_state = SDEV_CREATED;
3187 scsi_start_queue(sdev);
3191 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock_nowait);
3194 * scsi_internal_device_unblock - resume a device after a block request
3195 * @sdev: device to resume
3196 * @new_state: state to set the device to after unblocking
3198 * Restart the device queue for a previously suspended SCSI device. May sleep.
3200 * Returns zero if successful or a negative error code upon failure.
3203 * This routine transitions the device to the SDEV_RUNNING state or to one of
3204 * the offline states (which must be a legal transition) allowing the midlayer
3205 * to goose the queue for this device.
3207 static int scsi_internal_device_unblock(struct scsi_device *sdev,
3208 enum scsi_device_state new_state)
3212 mutex_lock(&sdev->state_mutex);
3213 ret = scsi_internal_device_unblock_nowait(sdev, new_state);
3214 mutex_unlock(&sdev->state_mutex);
3220 device_block(struct scsi_device *sdev, void *data)
3222 scsi_internal_device_block(sdev);
3226 target_block(struct device *dev, void *data)
3228 if (scsi_is_target_device(dev))
3229 starget_for_each_device(to_scsi_target(dev), NULL,
3235 scsi_target_block(struct device *dev)
3237 if (scsi_is_target_device(dev))
3238 starget_for_each_device(to_scsi_target(dev), NULL,
3241 device_for_each_child(dev, NULL, target_block);
3243 EXPORT_SYMBOL_GPL(scsi_target_block);
3246 device_unblock(struct scsi_device *sdev, void *data)
3248 scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
3252 target_unblock(struct device *dev, void *data)
3254 if (scsi_is_target_device(dev))
3255 starget_for_each_device(to_scsi_target(dev), data,
3261 scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
3263 if (scsi_is_target_device(dev))
3264 starget_for_each_device(to_scsi_target(dev), &new_state,
3267 device_for_each_child(dev, &new_state, target_unblock);
3269 EXPORT_SYMBOL_GPL(scsi_target_unblock);
3272 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
3273 * @sgl: scatter-gather list
3274 * @sg_count: number of segments in sg
3275 * @offset: offset in bytes into sg, on return offset into the mapped area
3276 * @len: bytes to map, on return number of bytes mapped
3278 * Returns virtual address of the start of the mapped page
3280 void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
3281 size_t *offset, size_t *len)
3284 size_t sg_len = 0, len_complete = 0;
3285 struct scatterlist *sg;
3288 WARN_ON(!irqs_disabled());
3290 for_each_sg(sgl, sg, sg_count, i) {
3291 len_complete = sg_len; /* Complete sg-entries */
3292 sg_len += sg->length;
3293 if (sg_len > *offset)
3297 if (unlikely(i == sg_count)) {
3298 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
3300 __func__, sg_len, *offset, sg_count);
3305 /* Offset starting from the beginning of first page in this sg-entry */
3306 *offset = *offset - len_complete + sg->offset;
3308 /* Assumption: contiguous pages can be accessed as "page + i" */
3309 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
3310 *offset &= ~PAGE_MASK;
3312 /* Bytes in this sg-entry from *offset to the end of the page */
3313 sg_len = PAGE_SIZE - *offset;
3317 return kmap_atomic(page);
3319 EXPORT_SYMBOL(scsi_kmap_atomic_sg);
3322 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
3323 * @virt: virtual address to be unmapped
3325 void scsi_kunmap_atomic_sg(void *virt)
3327 kunmap_atomic(virt);
3329 EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
3331 void sdev_disable_disk_events(struct scsi_device *sdev)
3333 atomic_inc(&sdev->disk_events_disable_depth);
3335 EXPORT_SYMBOL(sdev_disable_disk_events);
3337 void sdev_enable_disk_events(struct scsi_device *sdev)
3339 if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0))
3341 atomic_dec(&sdev->disk_events_disable_depth);
3343 EXPORT_SYMBOL(sdev_enable_disk_events);
3346 * scsi_vpd_lun_id - return a unique device identification
3347 * @sdev: SCSI device
3348 * @id: buffer for the identification
3349 * @id_len: length of the buffer
3351 * Copies a unique device identification into @id based
3352 * on the information in the VPD page 0x83 of the device.
3353 * The string will be formatted as a SCSI name string.
3355 * Returns the length of the identification or error on failure.
3356 * If the identifier is longer than the supplied buffer the actual
3357 * identifier length is returned and the buffer is not zero-padded.
3359 int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len)
3361 u8 cur_id_type = 0xff;
3363 const unsigned char *d, *cur_id_str;
3364 const struct scsi_vpd *vpd_pg83;
3365 int id_size = -EINVAL;
3368 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3375 * Look for the correct descriptor.
3376 * Order of preference for lun descriptor:
3377 * - SCSI name string
3378 * - NAA IEEE Registered Extended
3379 * - EUI-64 based 16-byte
3380 * - EUI-64 based 12-byte
3381 * - NAA IEEE Registered
3382 * - NAA IEEE Extended
3384 * as longer descriptors reduce the likelyhood
3385 * of identification clashes.
3388 /* The id string must be at least 20 bytes + terminating NULL byte */
3394 memset(id, 0, id_len);
3395 d = vpd_pg83->data + 4;
3396 while (d < vpd_pg83->data + vpd_pg83->len) {
3397 /* Skip designators not referring to the LUN */
3398 if ((d[1] & 0x30) != 0x00)
3401 switch (d[1] & 0xf) {
3404 if (cur_id_size > d[3])
3406 /* Prefer anything */
3407 if (cur_id_type > 0x01 && cur_id_type != 0xff)
3410 if (cur_id_size + 4 > id_len)
3411 cur_id_size = id_len - 4;
3413 cur_id_type = d[1] & 0xf;
3414 id_size = snprintf(id, id_len, "t10.%*pE",
3415 cur_id_size, cur_id_str);
3419 if (cur_id_size > d[3])
3421 /* Prefer NAA IEEE Registered Extended */
3422 if (cur_id_type == 0x3 &&
3423 cur_id_size == d[3])
3427 cur_id_type = d[1] & 0xf;
3428 switch (cur_id_size) {
3430 id_size = snprintf(id, id_len,
3435 id_size = snprintf(id, id_len,
3440 id_size = snprintf(id, id_len,
3451 if (cur_id_size > d[3])
3455 cur_id_type = d[1] & 0xf;
3456 switch (cur_id_size) {
3458 id_size = snprintf(id, id_len,
3463 id_size = snprintf(id, id_len,
3473 /* SCSI name string */
3474 if (cur_id_size + 4 > d[3])
3476 /* Prefer others for truncated descriptor */
3477 if (cur_id_size && d[3] > id_len)
3479 cur_id_size = id_size = d[3];
3481 cur_id_type = d[1] & 0xf;
3482 if (cur_id_size >= id_len)
3483 cur_id_size = id_len - 1;
3484 memcpy(id, cur_id_str, cur_id_size);
3485 /* Decrease priority for truncated descriptor */
3486 if (cur_id_size != id_size)
3499 EXPORT_SYMBOL(scsi_vpd_lun_id);
3502 * scsi_vpd_tpg_id - return a target port group identifier
3503 * @sdev: SCSI device
3505 * Returns the Target Port Group identifier from the information
3506 * froom VPD page 0x83 of the device.
3508 * Returns the identifier or error on failure.
3510 int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id)
3512 const unsigned char *d;
3513 const struct scsi_vpd *vpd_pg83;
3514 int group_id = -EAGAIN, rel_port = -1;
3517 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3523 d = vpd_pg83->data + 4;
3524 while (d < vpd_pg83->data + vpd_pg83->len) {
3525 switch (d[1] & 0xf) {
3527 /* Relative target port */
3528 rel_port = get_unaligned_be16(&d[6]);
3531 /* Target port group */
3532 group_id = get_unaligned_be16(&d[6]);
3541 if (group_id >= 0 && rel_id && rel_port != -1)
3546 EXPORT_SYMBOL(scsi_vpd_tpg_id);