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/mempool.h>
18 #include <linux/slab.h>
19 #include <linux/init.h>
20 #include <linux/pci.h>
21 #include <linux/delay.h>
22 #include <linux/hardirq.h>
23 #include <linux/scatterlist.h>
24 #include <linux/blk-mq.h>
25 #include <linux/ratelimit.h>
27 #include <scsi/scsi.h>
28 #include <scsi/scsi_cmnd.h>
29 #include <scsi/scsi_dbg.h>
30 #include <scsi/scsi_device.h>
31 #include <scsi/scsi_driver.h>
32 #include <scsi/scsi_eh.h>
33 #include <scsi/scsi_host.h>
35 #include <trace/events/scsi.h>
37 #include "scsi_priv.h"
38 #include "scsi_logging.h"
41 #define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools)
42 #define SG_MEMPOOL_SIZE 2
44 struct scsi_host_sg_pool {
47 struct kmem_cache *slab;
51 #define SP(x) { .size = x, "sgpool-" __stringify(x) }
52 #if (SCSI_MAX_SG_SEGMENTS < 32)
53 #error SCSI_MAX_SG_SEGMENTS is too small (must be 32 or greater)
55 static struct scsi_host_sg_pool scsi_sg_pools[] = {
58 #if (SCSI_MAX_SG_SEGMENTS > 32)
60 #if (SCSI_MAX_SG_SEGMENTS > 64)
62 #if (SCSI_MAX_SG_SEGMENTS > 128)
64 #if (SCSI_MAX_SG_SEGMENTS > 256)
65 #error SCSI_MAX_SG_SEGMENTS is too large (256 MAX)
70 SP(SCSI_MAX_SG_SEGMENTS)
74 struct kmem_cache *scsi_sdb_cache;
77 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
78 * not change behaviour from the previous unplug mechanism, experimentation
79 * may prove this needs changing.
81 #define SCSI_QUEUE_DELAY 3
84 scsi_set_blocked(struct scsi_cmnd *cmd, int reason)
86 struct Scsi_Host *host = cmd->device->host;
87 struct scsi_device *device = cmd->device;
88 struct scsi_target *starget = scsi_target(device);
91 * Set the appropriate busy bit for the device/host.
93 * If the host/device isn't busy, assume that something actually
94 * completed, and that we should be able to queue a command now.
96 * Note that the prior mid-layer assumption that any host could
97 * always queue at least one command is now broken. The mid-layer
98 * will implement a user specifiable stall (see
99 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
100 * if a command is requeued with no other commands outstanding
101 * either for the device or for the host.
104 case SCSI_MLQUEUE_HOST_BUSY:
105 atomic_set(&host->host_blocked, host->max_host_blocked);
107 case SCSI_MLQUEUE_DEVICE_BUSY:
108 case SCSI_MLQUEUE_EH_RETRY:
109 atomic_set(&device->device_blocked,
110 device->max_device_blocked);
112 case SCSI_MLQUEUE_TARGET_BUSY:
113 atomic_set(&starget->target_blocked,
114 starget->max_target_blocked);
119 static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd)
121 struct scsi_device *sdev = cmd->device;
122 struct request_queue *q = cmd->request->q;
124 blk_mq_requeue_request(cmd->request);
125 blk_mq_kick_requeue_list(q);
126 put_device(&sdev->sdev_gendev);
130 * __scsi_queue_insert - private queue insertion
131 * @cmd: The SCSI command being requeued
132 * @reason: The reason for the requeue
133 * @unbusy: Whether the queue should be unbusied
135 * This is a private queue insertion. The public interface
136 * scsi_queue_insert() always assumes the queue should be unbusied
137 * because it's always called before the completion. This function is
138 * for a requeue after completion, which should only occur in this
141 static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy)
143 struct scsi_device *device = cmd->device;
144 struct request_queue *q = device->request_queue;
147 SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd,
148 "Inserting command %p into mlqueue\n", cmd));
150 scsi_set_blocked(cmd, reason);
153 * Decrement the counters, since these commands are no longer
154 * active on the host/device.
157 scsi_device_unbusy(device);
160 * Requeue this command. It will go before all other commands
161 * that are already in the queue. Schedule requeue work under
162 * lock such that the kblockd_schedule_work() call happens
163 * before blk_cleanup_queue() finishes.
167 scsi_mq_requeue_cmd(cmd);
170 spin_lock_irqsave(q->queue_lock, flags);
171 blk_requeue_request(q, cmd->request);
172 kblockd_schedule_work(&device->requeue_work);
173 spin_unlock_irqrestore(q->queue_lock, flags);
177 * Function: scsi_queue_insert()
179 * Purpose: Insert a command in the midlevel queue.
181 * Arguments: cmd - command that we are adding to queue.
182 * reason - why we are inserting command to queue.
184 * Lock status: Assumed that lock is not held upon entry.
188 * Notes: We do this for one of two cases. Either the host is busy
189 * and it cannot accept any more commands for the time being,
190 * or the device returned QUEUE_FULL and can accept no more
192 * Notes: This could be called either from an interrupt context or a
193 * normal process context.
195 void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
197 __scsi_queue_insert(cmd, reason, 1);
200 * scsi_execute - insert request and wait for the result
203 * @data_direction: data direction
204 * @buffer: data buffer
205 * @bufflen: len of buffer
206 * @sense: optional sense buffer
207 * @timeout: request timeout in seconds
208 * @retries: number of times to retry request
209 * @flags: or into request flags;
210 * @resid: optional residual length
212 * returns the req->errors value which is the scsi_cmnd result
215 int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
216 int data_direction, void *buffer, unsigned bufflen,
217 unsigned char *sense, int timeout, int retries, u64 flags,
221 int write = (data_direction == DMA_TO_DEVICE);
222 int ret = DRIVER_ERROR << 24;
224 req = blk_get_request(sdev->request_queue, write, __GFP_WAIT);
227 blk_rq_set_block_pc(req);
229 if (bufflen && blk_rq_map_kern(sdev->request_queue, req,
230 buffer, bufflen, __GFP_WAIT))
233 req->cmd_len = COMMAND_SIZE(cmd[0]);
234 memcpy(req->cmd, cmd, req->cmd_len);
237 req->retries = retries;
238 req->timeout = timeout;
239 req->cmd_flags |= flags | REQ_QUIET | REQ_PREEMPT;
242 * head injection *required* here otherwise quiesce won't work
244 blk_execute_rq(req->q, NULL, req, 1);
247 * Some devices (USB mass-storage in particular) may transfer
248 * garbage data together with a residue indicating that the data
249 * is invalid. Prevent the garbage from being misinterpreted
250 * and prevent security leaks by zeroing out the excess data.
252 if (unlikely(req->resid_len > 0 && req->resid_len <= bufflen))
253 memset(buffer + (bufflen - req->resid_len), 0, req->resid_len);
256 *resid = req->resid_len;
259 blk_put_request(req);
263 EXPORT_SYMBOL(scsi_execute);
265 int scsi_execute_req_flags(struct scsi_device *sdev, const unsigned char *cmd,
266 int data_direction, void *buffer, unsigned bufflen,
267 struct scsi_sense_hdr *sshdr, int timeout, int retries,
268 int *resid, u64 flags)
274 sense = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO);
276 return DRIVER_ERROR << 24;
278 result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen,
279 sense, timeout, retries, flags, resid);
281 scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr);
286 EXPORT_SYMBOL(scsi_execute_req_flags);
289 * Function: scsi_init_cmd_errh()
291 * Purpose: Initialize cmd fields related to error handling.
293 * Arguments: cmd - command that is ready to be queued.
295 * Notes: This function has the job of initializing a number of
296 * fields related to error handling. Typically this will
297 * be called once for each command, as required.
299 static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
301 cmd->serial_number = 0;
302 scsi_set_resid(cmd, 0);
303 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
304 if (cmd->cmd_len == 0)
305 cmd->cmd_len = scsi_command_size(cmd->cmnd);
308 void scsi_device_unbusy(struct scsi_device *sdev)
310 struct Scsi_Host *shost = sdev->host;
311 struct scsi_target *starget = scsi_target(sdev);
314 atomic_dec(&shost->host_busy);
315 if (starget->can_queue > 0)
316 atomic_dec(&starget->target_busy);
318 if (unlikely(scsi_host_in_recovery(shost) &&
319 (shost->host_failed || shost->host_eh_scheduled))) {
320 spin_lock_irqsave(shost->host_lock, flags);
321 scsi_eh_wakeup(shost);
322 spin_unlock_irqrestore(shost->host_lock, flags);
325 atomic_dec(&sdev->device_busy);
328 static void scsi_kick_queue(struct request_queue *q)
331 blk_mq_start_hw_queues(q);
337 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
338 * and call blk_run_queue for all the scsi_devices on the target -
339 * including current_sdev first.
341 * Called with *no* scsi locks held.
343 static void scsi_single_lun_run(struct scsi_device *current_sdev)
345 struct Scsi_Host *shost = current_sdev->host;
346 struct scsi_device *sdev, *tmp;
347 struct scsi_target *starget = scsi_target(current_sdev);
350 spin_lock_irqsave(shost->host_lock, flags);
351 starget->starget_sdev_user = NULL;
352 spin_unlock_irqrestore(shost->host_lock, flags);
355 * Call blk_run_queue for all LUNs on the target, starting with
356 * current_sdev. We race with others (to set starget_sdev_user),
357 * but in most cases, we will be first. Ideally, each LU on the
358 * target would get some limited time or requests on the target.
360 scsi_kick_queue(current_sdev->request_queue);
362 spin_lock_irqsave(shost->host_lock, flags);
363 if (starget->starget_sdev_user)
365 list_for_each_entry_safe(sdev, tmp, &starget->devices,
366 same_target_siblings) {
367 if (sdev == current_sdev)
369 if (scsi_device_get(sdev))
372 spin_unlock_irqrestore(shost->host_lock, flags);
373 scsi_kick_queue(sdev->request_queue);
374 spin_lock_irqsave(shost->host_lock, flags);
376 scsi_device_put(sdev);
379 spin_unlock_irqrestore(shost->host_lock, flags);
382 static inline bool scsi_device_is_busy(struct scsi_device *sdev)
384 if (atomic_read(&sdev->device_busy) >= sdev->queue_depth)
386 if (atomic_read(&sdev->device_blocked) > 0)
391 static inline bool scsi_target_is_busy(struct scsi_target *starget)
393 if (starget->can_queue > 0) {
394 if (atomic_read(&starget->target_busy) >= starget->can_queue)
396 if (atomic_read(&starget->target_blocked) > 0)
402 static inline bool scsi_host_is_busy(struct Scsi_Host *shost)
404 if (shost->can_queue > 0 &&
405 atomic_read(&shost->host_busy) >= shost->can_queue)
407 if (atomic_read(&shost->host_blocked) > 0)
409 if (shost->host_self_blocked)
414 static void scsi_starved_list_run(struct Scsi_Host *shost)
416 LIST_HEAD(starved_list);
417 struct scsi_device *sdev;
420 spin_lock_irqsave(shost->host_lock, flags);
421 list_splice_init(&shost->starved_list, &starved_list);
423 while (!list_empty(&starved_list)) {
424 struct request_queue *slq;
427 * As long as shost is accepting commands and we have
428 * starved queues, call blk_run_queue. scsi_request_fn
429 * drops the queue_lock and can add us back to the
432 * host_lock protects the starved_list and starved_entry.
433 * scsi_request_fn must get the host_lock before checking
434 * or modifying starved_list or starved_entry.
436 if (scsi_host_is_busy(shost))
439 sdev = list_entry(starved_list.next,
440 struct scsi_device, starved_entry);
441 list_del_init(&sdev->starved_entry);
442 if (scsi_target_is_busy(scsi_target(sdev))) {
443 list_move_tail(&sdev->starved_entry,
444 &shost->starved_list);
449 * Once we drop the host lock, a racing scsi_remove_device()
450 * call may remove the sdev from the starved list and destroy
451 * it and the queue. Mitigate by taking a reference to the
452 * queue and never touching the sdev again after we drop the
453 * host lock. Note: if __scsi_remove_device() invokes
454 * blk_cleanup_queue() before the queue is run from this
455 * function then blk_run_queue() will return immediately since
456 * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING.
458 slq = sdev->request_queue;
459 if (!blk_get_queue(slq))
461 spin_unlock_irqrestore(shost->host_lock, flags);
463 scsi_kick_queue(slq);
466 spin_lock_irqsave(shost->host_lock, flags);
468 /* put any unprocessed entries back */
469 list_splice(&starved_list, &shost->starved_list);
470 spin_unlock_irqrestore(shost->host_lock, flags);
474 * Function: scsi_run_queue()
476 * Purpose: Select a proper request queue to serve next
478 * Arguments: q - last request's queue
482 * Notes: The previous command was completely finished, start
483 * a new one if possible.
485 static void scsi_run_queue(struct request_queue *q)
487 struct scsi_device *sdev = q->queuedata;
489 if (scsi_target(sdev)->single_lun)
490 scsi_single_lun_run(sdev);
491 if (!list_empty(&sdev->host->starved_list))
492 scsi_starved_list_run(sdev->host);
495 blk_mq_start_stopped_hw_queues(q, false);
500 void scsi_requeue_run_queue(struct work_struct *work)
502 struct scsi_device *sdev;
503 struct request_queue *q;
505 sdev = container_of(work, struct scsi_device, requeue_work);
506 q = sdev->request_queue;
511 * Function: scsi_requeue_command()
513 * Purpose: Handle post-processing of completed commands.
515 * Arguments: q - queue to operate on
516 * cmd - command that may need to be requeued.
520 * Notes: After command completion, there may be blocks left
521 * over which weren't finished by the previous command
522 * this can be for a number of reasons - the main one is
523 * I/O errors in the middle of the request, in which case
524 * we need to request the blocks that come after the bad
526 * Notes: Upon return, cmd is a stale pointer.
528 static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd)
530 struct scsi_device *sdev = cmd->device;
531 struct request *req = cmd->request;
534 spin_lock_irqsave(q->queue_lock, flags);
535 blk_unprep_request(req);
537 scsi_put_command(cmd);
538 blk_requeue_request(q, req);
539 spin_unlock_irqrestore(q->queue_lock, flags);
543 put_device(&sdev->sdev_gendev);
546 void scsi_run_host_queues(struct Scsi_Host *shost)
548 struct scsi_device *sdev;
550 shost_for_each_device(sdev, shost)
551 scsi_run_queue(sdev->request_queue);
554 static inline unsigned int scsi_sgtable_index(unsigned short nents)
558 BUG_ON(nents > SCSI_MAX_SG_SEGMENTS);
563 index = get_count_order(nents) - 3;
568 static void scsi_sg_free(struct scatterlist *sgl, unsigned int nents)
570 struct scsi_host_sg_pool *sgp;
572 sgp = scsi_sg_pools + scsi_sgtable_index(nents);
573 mempool_free(sgl, sgp->pool);
576 static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask)
578 struct scsi_host_sg_pool *sgp;
580 sgp = scsi_sg_pools + scsi_sgtable_index(nents);
581 return mempool_alloc(sgp->pool, gfp_mask);
584 static void scsi_free_sgtable(struct scsi_data_buffer *sdb, bool mq)
586 if (mq && sdb->table.nents <= SCSI_MAX_SG_SEGMENTS)
588 __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, mq, scsi_sg_free);
591 static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents, bool mq)
593 struct scatterlist *first_chunk = NULL;
594 gfp_t gfp_mask = mq ? GFP_NOIO : GFP_ATOMIC;
600 if (nents <= SCSI_MAX_SG_SEGMENTS) {
601 sdb->table.nents = nents;
602 sg_init_table(sdb->table.sgl, sdb->table.nents);
605 first_chunk = sdb->table.sgl;
608 ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS,
609 first_chunk, gfp_mask, scsi_sg_alloc);
611 scsi_free_sgtable(sdb, mq);
615 static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
617 if (cmd->request->cmd_type == REQ_TYPE_FS) {
618 struct scsi_driver *drv = scsi_cmd_to_driver(cmd);
620 if (drv->uninit_command)
621 drv->uninit_command(cmd);
625 static void scsi_mq_free_sgtables(struct scsi_cmnd *cmd)
627 if (cmd->sdb.table.nents)
628 scsi_free_sgtable(&cmd->sdb, true);
629 if (cmd->request->next_rq && cmd->request->next_rq->special)
630 scsi_free_sgtable(cmd->request->next_rq->special, true);
631 if (scsi_prot_sg_count(cmd))
632 scsi_free_sgtable(cmd->prot_sdb, true);
635 static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
637 struct scsi_device *sdev = cmd->device;
638 struct Scsi_Host *shost = sdev->host;
641 scsi_mq_free_sgtables(cmd);
642 scsi_uninit_cmd(cmd);
644 if (shost->use_cmd_list) {
645 BUG_ON(list_empty(&cmd->list));
646 spin_lock_irqsave(&sdev->list_lock, flags);
647 list_del_init(&cmd->list);
648 spin_unlock_irqrestore(&sdev->list_lock, flags);
653 * Function: scsi_release_buffers()
655 * Purpose: Free resources allocate for a scsi_command.
657 * Arguments: cmd - command that we are bailing.
659 * Lock status: Assumed that no lock is held upon entry.
663 * Notes: In the event that an upper level driver rejects a
664 * command, we must release resources allocated during
665 * the __init_io() function. Primarily this would involve
666 * the scatter-gather table.
668 static void scsi_release_buffers(struct scsi_cmnd *cmd)
670 if (cmd->sdb.table.nents)
671 scsi_free_sgtable(&cmd->sdb, false);
673 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
675 if (scsi_prot_sg_count(cmd))
676 scsi_free_sgtable(cmd->prot_sdb, false);
679 static void scsi_release_bidi_buffers(struct scsi_cmnd *cmd)
681 struct scsi_data_buffer *bidi_sdb = cmd->request->next_rq->special;
683 scsi_free_sgtable(bidi_sdb, false);
684 kmem_cache_free(scsi_sdb_cache, bidi_sdb);
685 cmd->request->next_rq->special = NULL;
688 static bool scsi_end_request(struct request *req, int error,
689 unsigned int bytes, unsigned int bidi_bytes)
691 struct scsi_cmnd *cmd = req->special;
692 struct scsi_device *sdev = cmd->device;
693 struct request_queue *q = sdev->request_queue;
695 if (blk_update_request(req, error, bytes))
698 /* Bidi request must be completed as a whole */
699 if (unlikely(bidi_bytes) &&
700 blk_update_request(req->next_rq, error, bidi_bytes))
703 if (blk_queue_add_random(q))
704 add_disk_randomness(req->rq_disk);
708 * In the MQ case the command gets freed by __blk_mq_end_request,
709 * so we have to do all cleanup that depends on it earlier.
711 * We also can't kick the queues from irq context, so we
712 * will have to defer it to a workqueue.
714 scsi_mq_uninit_cmd(cmd);
716 __blk_mq_end_request(req, error);
718 if (scsi_target(sdev)->single_lun ||
719 !list_empty(&sdev->host->starved_list))
720 kblockd_schedule_work(&sdev->requeue_work);
722 blk_mq_start_stopped_hw_queues(q, true);
727 scsi_release_bidi_buffers(cmd);
729 spin_lock_irqsave(q->queue_lock, flags);
730 blk_finish_request(req, error);
731 spin_unlock_irqrestore(q->queue_lock, flags);
733 scsi_release_buffers(cmd);
735 scsi_put_command(cmd);
739 put_device(&sdev->sdev_gendev);
744 * __scsi_error_from_host_byte - translate SCSI error code into errno
745 * @cmd: SCSI command (unused)
746 * @result: scsi error code
748 * Translate SCSI error code into standard UNIX errno.
750 * -ENOLINK temporary transport failure
751 * -EREMOTEIO permanent target failure, do not retry
752 * -EBADE permanent nexus failure, retry on other path
753 * -ENOSPC No write space available
754 * -ENODATA Medium error
755 * -EIO unspecified I/O error
757 static int __scsi_error_from_host_byte(struct scsi_cmnd *cmd, int result)
761 switch(host_byte(result)) {
762 case DID_TRANSPORT_FAILFAST:
765 case DID_TARGET_FAILURE:
766 set_host_byte(cmd, DID_OK);
769 case DID_NEXUS_FAILURE:
770 set_host_byte(cmd, DID_OK);
773 case DID_ALLOC_FAILURE:
774 set_host_byte(cmd, DID_OK);
777 case DID_MEDIUM_ERROR:
778 set_host_byte(cmd, DID_OK);
790 * Function: scsi_io_completion()
792 * Purpose: Completion processing for block device I/O requests.
794 * Arguments: cmd - command that is finished.
796 * Lock status: Assumed that no lock is held upon entry.
800 * Notes: We will finish off the specified number of sectors. If we
801 * are done, the command block will be released and the queue
802 * function will be goosed. If we are not done then we have to
803 * figure out what to do next:
805 * a) We can call scsi_requeue_command(). The request
806 * will be unprepared and put back on the queue. Then
807 * a new command will be created for it. This should
808 * be used if we made forward progress, or if we want
809 * to switch from READ(10) to READ(6) for example.
811 * b) We can call __scsi_queue_insert(). The request will
812 * be put back on the queue and retried using the same
813 * command as before, possibly after a delay.
815 * c) We can call scsi_end_request() with -EIO to fail
816 * the remainder of the request.
818 void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
820 int result = cmd->result;
821 struct request_queue *q = cmd->device->request_queue;
822 struct request *req = cmd->request;
824 struct scsi_sense_hdr sshdr;
825 bool sense_valid = false;
826 int sense_deferred = 0, level = 0;
827 enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,
828 ACTION_DELAYED_RETRY} action;
829 unsigned long wait_for = (cmd->allowed + 1) * req->timeout;
832 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
834 sense_deferred = scsi_sense_is_deferred(&sshdr);
837 if (req->cmd_type == REQ_TYPE_BLOCK_PC) { /* SG_IO ioctl from block level */
839 if (sense_valid && req->sense) {
841 * SG_IO wants current and deferred errors
843 int len = 8 + cmd->sense_buffer[7];
845 if (len > SCSI_SENSE_BUFFERSIZE)
846 len = SCSI_SENSE_BUFFERSIZE;
847 memcpy(req->sense, cmd->sense_buffer, len);
848 req->sense_len = len;
851 error = __scsi_error_from_host_byte(cmd, result);
854 * __scsi_error_from_host_byte may have reset the host_byte
856 req->errors = cmd->result;
858 req->resid_len = scsi_get_resid(cmd);
860 if (scsi_bidi_cmnd(cmd)) {
862 * Bidi commands Must be complete as a whole,
863 * both sides at once.
865 req->next_rq->resid_len = scsi_in(cmd)->resid;
866 if (scsi_end_request(req, 0, blk_rq_bytes(req),
867 blk_rq_bytes(req->next_rq)))
871 } else if (blk_rq_bytes(req) == 0 && result && !sense_deferred) {
873 * Certain non BLOCK_PC requests are commands that don't
874 * actually transfer anything (FLUSH), so cannot use
875 * good_bytes != blk_rq_bytes(req) as the signal for an error.
876 * This sets the error explicitly for the problem case.
878 error = __scsi_error_from_host_byte(cmd, result);
881 /* no bidi support for !REQ_TYPE_BLOCK_PC yet */
882 BUG_ON(blk_bidi_rq(req));
885 * Next deal with any sectors which we were able to correctly
888 SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd,
889 "%u sectors total, %d bytes done.\n",
890 blk_rq_sectors(req), good_bytes));
893 * Recovered errors need reporting, but they're always treated
894 * as success, so fiddle the result code here. For BLOCK_PC
895 * we already took a copy of the original into rq->errors which
896 * is what gets returned to the user
898 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
899 /* if ATA PASS-THROUGH INFORMATION AVAILABLE skip
900 * print since caller wants ATA registers. Only occurs on
901 * SCSI ATA PASS_THROUGH commands when CK_COND=1
903 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
905 else if (!(req->cmd_flags & REQ_QUIET))
906 scsi_print_sense(cmd);
908 /* BLOCK_PC may have set error */
913 * If we finished all bytes in the request we are done now.
915 if (!scsi_end_request(req, error, good_bytes, 0))
919 * Kill remainder if no retrys.
921 if (error && scsi_noretry_cmd(cmd)) {
922 if (scsi_end_request(req, error, blk_rq_bytes(req), 0))
928 * If there had been no error, but we have leftover bytes in the
929 * requeues just queue the command up again.
934 error = __scsi_error_from_host_byte(cmd, result);
936 if (host_byte(result) == DID_RESET) {
937 /* Third party bus reset or reset for error recovery
938 * reasons. Just retry the command and see what
941 action = ACTION_RETRY;
942 } else if (sense_valid && !sense_deferred) {
943 switch (sshdr.sense_key) {
945 if (cmd->device->removable) {
946 /* Detected disc change. Set a bit
947 * and quietly refuse further access.
949 cmd->device->changed = 1;
950 action = ACTION_FAIL;
952 /* Must have been a power glitch, or a
953 * bus reset. Could not have been a
954 * media change, so we just retry the
955 * command and see what happens.
957 action = ACTION_RETRY;
960 case ILLEGAL_REQUEST:
961 /* If we had an ILLEGAL REQUEST returned, then
962 * we may have performed an unsupported
963 * command. The only thing this should be
964 * would be a ten byte read where only a six
965 * byte read was supported. Also, on a system
966 * where READ CAPACITY failed, we may have
967 * read past the end of the disk.
969 if ((cmd->device->use_10_for_rw &&
970 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
971 (cmd->cmnd[0] == READ_10 ||
972 cmd->cmnd[0] == WRITE_10)) {
973 /* This will issue a new 6-byte command. */
974 cmd->device->use_10_for_rw = 0;
975 action = ACTION_REPREP;
976 } else if (sshdr.asc == 0x10) /* DIX */ {
977 action = ACTION_FAIL;
979 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
980 } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
981 action = ACTION_FAIL;
984 action = ACTION_FAIL;
986 case ABORTED_COMMAND:
987 action = ACTION_FAIL;
988 if (sshdr.asc == 0x10) /* DIF */
992 /* If the device is in the process of becoming
993 * ready, or has a temporary blockage, retry.
995 if (sshdr.asc == 0x04) {
996 switch (sshdr.ascq) {
997 case 0x01: /* becoming ready */
998 case 0x04: /* format in progress */
999 case 0x05: /* rebuild in progress */
1000 case 0x06: /* recalculation in progress */
1001 case 0x07: /* operation in progress */
1002 case 0x08: /* Long write in progress */
1003 case 0x09: /* self test in progress */
1004 case 0x14: /* space allocation in progress */
1005 action = ACTION_DELAYED_RETRY;
1008 action = ACTION_FAIL;
1012 action = ACTION_FAIL;
1014 case VOLUME_OVERFLOW:
1015 /* See SSC3rXX or current. */
1016 action = ACTION_FAIL;
1019 action = ACTION_FAIL;
1023 action = ACTION_FAIL;
1025 if (action != ACTION_FAIL &&
1026 time_before(cmd->jiffies_at_alloc + wait_for, jiffies))
1027 action = ACTION_FAIL;
1031 /* Give up and fail the remainder of the request */
1032 if (!(req->cmd_flags & REQ_QUIET)) {
1033 static DEFINE_RATELIMIT_STATE(_rs,
1034 DEFAULT_RATELIMIT_INTERVAL,
1035 DEFAULT_RATELIMIT_BURST);
1037 if (unlikely(scsi_logging_level))
1038 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
1039 SCSI_LOG_MLCOMPLETE_BITS);
1042 * if logging is enabled the failure will be printed
1043 * in scsi_log_completion(), so avoid duplicate messages
1045 if (!level && __ratelimit(&_rs)) {
1046 scsi_print_result(cmd, NULL, FAILED);
1047 if (driver_byte(result) & DRIVER_SENSE)
1048 scsi_print_sense(cmd);
1049 scsi_print_command(cmd);
1052 if (!scsi_end_request(req, error, blk_rq_err_bytes(req), 0))
1057 /* Unprep the request and put it back at the head of the queue.
1058 * A new command will be prepared and issued.
1061 cmd->request->cmd_flags &= ~REQ_DONTPREP;
1062 scsi_mq_uninit_cmd(cmd);
1063 scsi_mq_requeue_cmd(cmd);
1065 scsi_release_buffers(cmd);
1066 scsi_requeue_command(q, cmd);
1070 /* Retry the same command immediately */
1071 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, 0);
1073 case ACTION_DELAYED_RETRY:
1074 /* Retry the same command after a delay */
1075 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, 0);
1080 static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb)
1085 * If sg table allocation fails, requeue request later.
1087 if (unlikely(scsi_alloc_sgtable(sdb, req->nr_phys_segments,
1088 req->mq_ctx != NULL)))
1089 return BLKPREP_DEFER;
1092 * Next, walk the list, and fill in the addresses and sizes of
1095 count = blk_rq_map_sg(req->q, req, sdb->table.sgl);
1096 BUG_ON(count > sdb->table.nents);
1097 sdb->table.nents = count;
1098 sdb->length = blk_rq_bytes(req);
1103 * Function: scsi_init_io()
1105 * Purpose: SCSI I/O initialize function.
1107 * Arguments: cmd - Command descriptor we wish to initialize
1109 * Returns: 0 on success
1110 * BLKPREP_DEFER if the failure is retryable
1111 * BLKPREP_KILL if the failure is fatal
1113 int scsi_init_io(struct scsi_cmnd *cmd)
1115 struct scsi_device *sdev = cmd->device;
1116 struct request *rq = cmd->request;
1117 bool is_mq = (rq->mq_ctx != NULL);
1120 BUG_ON(!rq->nr_phys_segments);
1122 error = scsi_init_sgtable(rq, &cmd->sdb);
1126 if (blk_bidi_rq(rq)) {
1127 if (!rq->q->mq_ops) {
1128 struct scsi_data_buffer *bidi_sdb =
1129 kmem_cache_zalloc(scsi_sdb_cache, GFP_ATOMIC);
1131 error = BLKPREP_DEFER;
1135 rq->next_rq->special = bidi_sdb;
1138 error = scsi_init_sgtable(rq->next_rq, rq->next_rq->special);
1143 if (blk_integrity_rq(rq)) {
1144 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1147 BUG_ON(prot_sdb == NULL);
1148 ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
1150 if (scsi_alloc_sgtable(prot_sdb, ivecs, is_mq)) {
1151 error = BLKPREP_DEFER;
1155 count = blk_rq_map_integrity_sg(rq->q, rq->bio,
1156 prot_sdb->table.sgl);
1157 BUG_ON(unlikely(count > ivecs));
1158 BUG_ON(unlikely(count > queue_max_integrity_segments(rq->q)));
1160 cmd->prot_sdb = prot_sdb;
1161 cmd->prot_sdb->table.nents = count;
1167 scsi_mq_free_sgtables(cmd);
1169 scsi_release_buffers(cmd);
1170 cmd->request->special = NULL;
1171 scsi_put_command(cmd);
1172 put_device(&sdev->sdev_gendev);
1176 EXPORT_SYMBOL(scsi_init_io);
1178 static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev,
1179 struct request *req)
1181 struct scsi_cmnd *cmd;
1183 if (!req->special) {
1184 /* Bail if we can't get a reference to the device */
1185 if (!get_device(&sdev->sdev_gendev))
1188 cmd = scsi_get_command(sdev, GFP_ATOMIC);
1189 if (unlikely(!cmd)) {
1190 put_device(&sdev->sdev_gendev);
1198 /* pull a tag out of the request if we have one */
1199 cmd->tag = req->tag;
1202 cmd->cmnd = req->cmd;
1203 cmd->prot_op = SCSI_PROT_NORMAL;
1208 static int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
1210 struct scsi_cmnd *cmd = req->special;
1213 * BLOCK_PC requests may transfer data, in which case they must
1214 * a bio attached to them. Or they might contain a SCSI command
1215 * that does not transfer data, in which case they may optionally
1216 * submit a request without an attached bio.
1219 int ret = scsi_init_io(cmd);
1223 BUG_ON(blk_rq_bytes(req));
1225 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1228 cmd->cmd_len = req->cmd_len;
1229 cmd->transfersize = blk_rq_bytes(req);
1230 cmd->allowed = req->retries;
1235 * Setup a REQ_TYPE_FS command. These are simple request from filesystems
1236 * that still need to be translated to SCSI CDBs from the ULD.
1238 static int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
1240 struct scsi_cmnd *cmd = req->special;
1242 if (unlikely(sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh
1243 && sdev->scsi_dh_data->scsi_dh->prep_fn)) {
1244 int ret = sdev->scsi_dh_data->scsi_dh->prep_fn(sdev, req);
1245 if (ret != BLKPREP_OK)
1249 memset(cmd->cmnd, 0, BLK_MAX_CDB);
1250 return scsi_cmd_to_driver(cmd)->init_command(cmd);
1253 static int scsi_setup_cmnd(struct scsi_device *sdev, struct request *req)
1255 struct scsi_cmnd *cmd = req->special;
1257 if (!blk_rq_bytes(req))
1258 cmd->sc_data_direction = DMA_NONE;
1259 else if (rq_data_dir(req) == WRITE)
1260 cmd->sc_data_direction = DMA_TO_DEVICE;
1262 cmd->sc_data_direction = DMA_FROM_DEVICE;
1264 switch (req->cmd_type) {
1266 return scsi_setup_fs_cmnd(sdev, req);
1267 case REQ_TYPE_BLOCK_PC:
1268 return scsi_setup_blk_pc_cmnd(sdev, req);
1270 return BLKPREP_KILL;
1275 scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
1277 int ret = BLKPREP_OK;
1280 * If the device is not in running state we will reject some
1283 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
1284 switch (sdev->sdev_state) {
1286 case SDEV_TRANSPORT_OFFLINE:
1288 * If the device is offline we refuse to process any
1289 * commands. The device must be brought online
1290 * before trying any recovery commands.
1292 sdev_printk(KERN_ERR, sdev,
1293 "rejecting I/O to offline device\n");
1298 * If the device is fully deleted, we refuse to
1299 * process any commands as well.
1301 sdev_printk(KERN_ERR, sdev,
1302 "rejecting I/O to dead device\n");
1307 case SDEV_CREATED_BLOCK:
1309 * If the devices is blocked we defer normal commands.
1311 if (!(req->cmd_flags & REQ_PREEMPT))
1312 ret = BLKPREP_DEFER;
1316 * For any other not fully online state we only allow
1317 * special commands. In particular any user initiated
1318 * command is not allowed.
1320 if (!(req->cmd_flags & REQ_PREEMPT))
1329 scsi_prep_return(struct request_queue *q, struct request *req, int ret)
1331 struct scsi_device *sdev = q->queuedata;
1335 req->errors = DID_NO_CONNECT << 16;
1336 /* release the command and kill it */
1338 struct scsi_cmnd *cmd = req->special;
1339 scsi_release_buffers(cmd);
1340 scsi_put_command(cmd);
1341 put_device(&sdev->sdev_gendev);
1342 req->special = NULL;
1347 * If we defer, the blk_peek_request() returns NULL, but the
1348 * queue must be restarted, so we schedule a callback to happen
1351 if (atomic_read(&sdev->device_busy) == 0)
1352 blk_delay_queue(q, SCSI_QUEUE_DELAY);
1355 req->cmd_flags |= REQ_DONTPREP;
1361 static int scsi_prep_fn(struct request_queue *q, struct request *req)
1363 struct scsi_device *sdev = q->queuedata;
1364 struct scsi_cmnd *cmd;
1367 ret = scsi_prep_state_check(sdev, req);
1368 if (ret != BLKPREP_OK)
1371 cmd = scsi_get_cmd_from_req(sdev, req);
1372 if (unlikely(!cmd)) {
1373 ret = BLKPREP_DEFER;
1377 ret = scsi_setup_cmnd(sdev, req);
1379 return scsi_prep_return(q, req, ret);
1382 static void scsi_unprep_fn(struct request_queue *q, struct request *req)
1384 scsi_uninit_cmd(req->special);
1388 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1391 * Called with the queue_lock held.
1393 static inline int scsi_dev_queue_ready(struct request_queue *q,
1394 struct scsi_device *sdev)
1398 busy = atomic_inc_return(&sdev->device_busy) - 1;
1399 if (atomic_read(&sdev->device_blocked)) {
1404 * unblock after device_blocked iterates to zero
1406 if (atomic_dec_return(&sdev->device_blocked) > 0) {
1408 * For the MQ case we take care of this in the caller.
1411 blk_delay_queue(q, SCSI_QUEUE_DELAY);
1414 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev,
1415 "unblocking device at zero depth\n"));
1418 if (busy >= sdev->queue_depth)
1423 atomic_dec(&sdev->device_busy);
1428 * scsi_target_queue_ready: checks if there we can send commands to target
1429 * @sdev: scsi device on starget to check.
1431 static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1432 struct scsi_device *sdev)
1434 struct scsi_target *starget = scsi_target(sdev);
1437 if (starget->single_lun) {
1438 spin_lock_irq(shost->host_lock);
1439 if (starget->starget_sdev_user &&
1440 starget->starget_sdev_user != sdev) {
1441 spin_unlock_irq(shost->host_lock);
1444 starget->starget_sdev_user = sdev;
1445 spin_unlock_irq(shost->host_lock);
1448 if (starget->can_queue <= 0)
1451 busy = atomic_inc_return(&starget->target_busy) - 1;
1452 if (atomic_read(&starget->target_blocked) > 0) {
1457 * unblock after target_blocked iterates to zero
1459 if (atomic_dec_return(&starget->target_blocked) > 0)
1462 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1463 "unblocking target at zero depth\n"));
1466 if (busy >= starget->can_queue)
1472 spin_lock_irq(shost->host_lock);
1473 list_move_tail(&sdev->starved_entry, &shost->starved_list);
1474 spin_unlock_irq(shost->host_lock);
1476 if (starget->can_queue > 0)
1477 atomic_dec(&starget->target_busy);
1482 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1483 * return 0. We must end up running the queue again whenever 0 is
1484 * returned, else IO can hang.
1486 static inline int scsi_host_queue_ready(struct request_queue *q,
1487 struct Scsi_Host *shost,
1488 struct scsi_device *sdev)
1492 if (scsi_host_in_recovery(shost))
1495 busy = atomic_inc_return(&shost->host_busy) - 1;
1496 if (atomic_read(&shost->host_blocked) > 0) {
1501 * unblock after host_blocked iterates to zero
1503 if (atomic_dec_return(&shost->host_blocked) > 0)
1507 shost_printk(KERN_INFO, shost,
1508 "unblocking host at zero depth\n"));
1511 if (shost->can_queue > 0 && busy >= shost->can_queue)
1513 if (shost->host_self_blocked)
1516 /* We're OK to process the command, so we can't be starved */
1517 if (!list_empty(&sdev->starved_entry)) {
1518 spin_lock_irq(shost->host_lock);
1519 if (!list_empty(&sdev->starved_entry))
1520 list_del_init(&sdev->starved_entry);
1521 spin_unlock_irq(shost->host_lock);
1527 spin_lock_irq(shost->host_lock);
1528 if (list_empty(&sdev->starved_entry))
1529 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1530 spin_unlock_irq(shost->host_lock);
1532 atomic_dec(&shost->host_busy);
1537 * Busy state exporting function for request stacking drivers.
1539 * For efficiency, no lock is taken to check the busy state of
1540 * shost/starget/sdev, since the returned value is not guaranteed and
1541 * may be changed after request stacking drivers call the function,
1542 * regardless of taking lock or not.
1544 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1545 * needs to return 'not busy'. Otherwise, request stacking drivers
1546 * may hold requests forever.
1548 static int scsi_lld_busy(struct request_queue *q)
1550 struct scsi_device *sdev = q->queuedata;
1551 struct Scsi_Host *shost;
1553 if (blk_queue_dying(q))
1559 * Ignore host/starget busy state.
1560 * Since block layer does not have a concept of fairness across
1561 * multiple queues, congestion of host/starget needs to be handled
1564 if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
1571 * Kill a request for a dead device
1573 static void scsi_kill_request(struct request *req, struct request_queue *q)
1575 struct scsi_cmnd *cmd = req->special;
1576 struct scsi_device *sdev;
1577 struct scsi_target *starget;
1578 struct Scsi_Host *shost;
1580 blk_start_request(req);
1582 scmd_printk(KERN_INFO, cmd, "killing request\n");
1585 starget = scsi_target(sdev);
1587 scsi_init_cmd_errh(cmd);
1588 cmd->result = DID_NO_CONNECT << 16;
1589 atomic_inc(&cmd->device->iorequest_cnt);
1592 * SCSI request completion path will do scsi_device_unbusy(),
1593 * bump busy counts. To bump the counters, we need to dance
1594 * with the locks as normal issue path does.
1596 atomic_inc(&sdev->device_busy);
1597 atomic_inc(&shost->host_busy);
1598 if (starget->can_queue > 0)
1599 atomic_inc(&starget->target_busy);
1601 blk_complete_request(req);
1604 static void scsi_softirq_done(struct request *rq)
1606 struct scsi_cmnd *cmd = rq->special;
1607 unsigned long wait_for = (cmd->allowed + 1) * rq->timeout;
1610 INIT_LIST_HEAD(&cmd->eh_entry);
1612 atomic_inc(&cmd->device->iodone_cnt);
1614 atomic_inc(&cmd->device->ioerr_cnt);
1616 disposition = scsi_decide_disposition(cmd);
1617 if (disposition != SUCCESS &&
1618 time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
1619 sdev_printk(KERN_ERR, cmd->device,
1620 "timing out command, waited %lus\n",
1622 disposition = SUCCESS;
1625 scsi_log_completion(cmd, disposition);
1627 switch (disposition) {
1629 scsi_finish_command(cmd);
1632 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
1634 case ADD_TO_MLQUEUE:
1635 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1638 if (!scsi_eh_scmd_add(cmd, 0))
1639 scsi_finish_command(cmd);
1644 * scsi_done - Invoke completion on finished SCSI command.
1645 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
1646 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
1648 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
1649 * which regains ownership of the SCSI command (de facto) from a LLDD, and
1650 * calls blk_complete_request() for further processing.
1652 * This function is interrupt context safe.
1654 static void scsi_done(struct scsi_cmnd *cmd)
1656 trace_scsi_dispatch_cmd_done(cmd);
1657 blk_complete_request(cmd->request);
1661 * Function: scsi_request_fn()
1663 * Purpose: Main strategy routine for SCSI.
1665 * Arguments: q - Pointer to actual queue.
1669 * Lock status: IO request lock assumed to be held when called.
1671 static void scsi_request_fn(struct request_queue *q)
1672 __releases(q->queue_lock)
1673 __acquires(q->queue_lock)
1675 struct scsi_device *sdev = q->queuedata;
1676 struct Scsi_Host *shost;
1677 struct scsi_cmnd *cmd;
1678 struct request *req;
1681 * To start with, we keep looping until the queue is empty, or until
1682 * the host is no longer able to accept any more requests.
1688 * get next queueable request. We do this early to make sure
1689 * that the request is fully prepared even if we cannot
1692 req = blk_peek_request(q);
1696 if (unlikely(!scsi_device_online(sdev))) {
1697 sdev_printk(KERN_ERR, sdev,
1698 "rejecting I/O to offline device\n");
1699 scsi_kill_request(req, q);
1703 if (!scsi_dev_queue_ready(q, sdev))
1707 * Remove the request from the request list.
1709 if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req)))
1710 blk_start_request(req);
1712 spin_unlock_irq(q->queue_lock);
1714 if (unlikely(cmd == NULL)) {
1715 printk(KERN_CRIT "impossible request in %s.\n"
1716 "please mail a stack trace to "
1717 "linux-scsi@vger.kernel.org\n",
1719 blk_dump_rq_flags(req, "foo");
1724 * We hit this when the driver is using a host wide
1725 * tag map. For device level tag maps the queue_depth check
1726 * in the device ready fn would prevent us from trying
1727 * to allocate a tag. Since the map is a shared host resource
1728 * we add the dev to the starved list so it eventually gets
1729 * a run when a tag is freed.
1731 if (blk_queue_tagged(q) && !(req->cmd_flags & REQ_QUEUED)) {
1732 spin_lock_irq(shost->host_lock);
1733 if (list_empty(&sdev->starved_entry))
1734 list_add_tail(&sdev->starved_entry,
1735 &shost->starved_list);
1736 spin_unlock_irq(shost->host_lock);
1740 if (!scsi_target_queue_ready(shost, sdev))
1743 if (!scsi_host_queue_ready(q, shost, sdev))
1744 goto host_not_ready;
1746 if (sdev->simple_tags)
1747 cmd->flags |= SCMD_TAGGED;
1749 cmd->flags &= ~SCMD_TAGGED;
1752 * Finally, initialize any error handling parameters, and set up
1753 * the timers for timeouts.
1755 scsi_init_cmd_errh(cmd);
1758 * Dispatch the command to the low-level driver.
1760 cmd->scsi_done = scsi_done;
1761 rtn = scsi_dispatch_cmd(cmd);
1763 scsi_queue_insert(cmd, rtn);
1764 spin_lock_irq(q->queue_lock);
1767 spin_lock_irq(q->queue_lock);
1773 if (scsi_target(sdev)->can_queue > 0)
1774 atomic_dec(&scsi_target(sdev)->target_busy);
1777 * lock q, handle tag, requeue req, and decrement device_busy. We
1778 * must return with queue_lock held.
1780 * Decrementing device_busy without checking it is OK, as all such
1781 * cases (host limits or settings) should run the queue at some
1784 spin_lock_irq(q->queue_lock);
1785 blk_requeue_request(q, req);
1786 atomic_dec(&sdev->device_busy);
1788 if (!atomic_read(&sdev->device_busy) && !scsi_device_blocked(sdev))
1789 blk_delay_queue(q, SCSI_QUEUE_DELAY);
1792 static inline int prep_to_mq(int ret)
1798 return BLK_MQ_RQ_QUEUE_BUSY;
1800 return BLK_MQ_RQ_QUEUE_ERROR;
1804 static int scsi_mq_prep_fn(struct request *req)
1806 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1807 struct scsi_device *sdev = req->q->queuedata;
1808 struct Scsi_Host *shost = sdev->host;
1809 unsigned char *sense_buf = cmd->sense_buffer;
1810 struct scatterlist *sg;
1812 memset(cmd, 0, sizeof(struct scsi_cmnd));
1818 cmd->sense_buffer = sense_buf;
1820 cmd->tag = req->tag;
1822 cmd->cmnd = req->cmd;
1823 cmd->prot_op = SCSI_PROT_NORMAL;
1825 INIT_LIST_HEAD(&cmd->list);
1826 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
1827 cmd->jiffies_at_alloc = jiffies;
1829 if (shost->use_cmd_list) {
1830 spin_lock_irq(&sdev->list_lock);
1831 list_add_tail(&cmd->list, &sdev->cmd_list);
1832 spin_unlock_irq(&sdev->list_lock);
1835 sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
1836 cmd->sdb.table.sgl = sg;
1838 if (scsi_host_get_prot(shost)) {
1839 cmd->prot_sdb = (void *)sg +
1840 shost->sg_tablesize * sizeof(struct scatterlist);
1841 memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer));
1843 cmd->prot_sdb->table.sgl =
1844 (struct scatterlist *)(cmd->prot_sdb + 1);
1847 if (blk_bidi_rq(req)) {
1848 struct request *next_rq = req->next_rq;
1849 struct scsi_data_buffer *bidi_sdb = blk_mq_rq_to_pdu(next_rq);
1851 memset(bidi_sdb, 0, sizeof(struct scsi_data_buffer));
1852 bidi_sdb->table.sgl =
1853 (struct scatterlist *)(bidi_sdb + 1);
1855 next_rq->special = bidi_sdb;
1858 blk_mq_start_request(req);
1860 return scsi_setup_cmnd(sdev, req);
1863 static void scsi_mq_done(struct scsi_cmnd *cmd)
1865 trace_scsi_dispatch_cmd_done(cmd);
1866 blk_mq_complete_request(cmd->request);
1869 static int scsi_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *req,
1872 struct request_queue *q = req->q;
1873 struct scsi_device *sdev = q->queuedata;
1874 struct Scsi_Host *shost = sdev->host;
1875 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1879 ret = prep_to_mq(scsi_prep_state_check(sdev, req));
1883 ret = BLK_MQ_RQ_QUEUE_BUSY;
1884 if (!get_device(&sdev->sdev_gendev))
1887 if (!scsi_dev_queue_ready(q, sdev))
1888 goto out_put_device;
1889 if (!scsi_target_queue_ready(shost, sdev))
1890 goto out_dec_device_busy;
1891 if (!scsi_host_queue_ready(q, shost, sdev))
1892 goto out_dec_target_busy;
1895 if (!(req->cmd_flags & REQ_DONTPREP)) {
1896 ret = prep_to_mq(scsi_mq_prep_fn(req));
1898 goto out_dec_host_busy;
1899 req->cmd_flags |= REQ_DONTPREP;
1901 blk_mq_start_request(req);
1904 if (sdev->simple_tags)
1905 cmd->flags |= SCMD_TAGGED;
1907 cmd->flags &= ~SCMD_TAGGED;
1909 scsi_init_cmd_errh(cmd);
1910 cmd->scsi_done = scsi_mq_done;
1912 reason = scsi_dispatch_cmd(cmd);
1914 scsi_set_blocked(cmd, reason);
1915 ret = BLK_MQ_RQ_QUEUE_BUSY;
1916 goto out_dec_host_busy;
1919 return BLK_MQ_RQ_QUEUE_OK;
1922 atomic_dec(&shost->host_busy);
1923 out_dec_target_busy:
1924 if (scsi_target(sdev)->can_queue > 0)
1925 atomic_dec(&scsi_target(sdev)->target_busy);
1926 out_dec_device_busy:
1927 atomic_dec(&sdev->device_busy);
1929 put_device(&sdev->sdev_gendev);
1932 case BLK_MQ_RQ_QUEUE_BUSY:
1933 blk_mq_stop_hw_queue(hctx);
1934 if (atomic_read(&sdev->device_busy) == 0 &&
1935 !scsi_device_blocked(sdev))
1936 blk_mq_delay_queue(hctx, SCSI_QUEUE_DELAY);
1938 case BLK_MQ_RQ_QUEUE_ERROR:
1940 * Make sure to release all allocated ressources when
1941 * we hit an error, as we will never see this command
1944 if (req->cmd_flags & REQ_DONTPREP)
1945 scsi_mq_uninit_cmd(cmd);
1953 static enum blk_eh_timer_return scsi_timeout(struct request *req,
1957 return BLK_EH_RESET_TIMER;
1958 return scsi_times_out(req);
1961 static int scsi_init_request(void *data, struct request *rq,
1962 unsigned int hctx_idx, unsigned int request_idx,
1963 unsigned int numa_node)
1965 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1967 cmd->sense_buffer = kzalloc_node(SCSI_SENSE_BUFFERSIZE, GFP_KERNEL,
1969 if (!cmd->sense_buffer)
1974 static void scsi_exit_request(void *data, struct request *rq,
1975 unsigned int hctx_idx, unsigned int request_idx)
1977 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1979 kfree(cmd->sense_buffer);
1982 static u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost)
1984 struct device *host_dev;
1985 u64 bounce_limit = 0xffffffff;
1987 if (shost->unchecked_isa_dma)
1988 return BLK_BOUNCE_ISA;
1990 * Platforms with virtual-DMA translation
1991 * hardware have no practical limit.
1993 if (!PCI_DMA_BUS_IS_PHYS)
1994 return BLK_BOUNCE_ANY;
1996 host_dev = scsi_get_device(shost);
1997 if (host_dev && host_dev->dma_mask)
1998 bounce_limit = (u64)dma_max_pfn(host_dev) << PAGE_SHIFT;
2000 return bounce_limit;
2003 static void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
2005 struct device *dev = shost->dma_dev;
2008 * this limit is imposed by hardware restrictions
2010 blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
2011 SCSI_MAX_SG_CHAIN_SEGMENTS));
2013 if (scsi_host_prot_dma(shost)) {
2014 shost->sg_prot_tablesize =
2015 min_not_zero(shost->sg_prot_tablesize,
2016 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
2017 BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
2018 blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
2021 blk_queue_max_hw_sectors(q, shost->max_sectors);
2022 blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost));
2023 blk_queue_segment_boundary(q, shost->dma_boundary);
2024 dma_set_seg_boundary(dev, shost->dma_boundary);
2026 blk_queue_max_segment_size(q, dma_get_max_seg_size(dev));
2028 if (!shost->use_clustering)
2029 q->limits.cluster = 0;
2032 * set a reasonable default alignment on word boundaries: the
2033 * host and device may alter it using
2034 * blk_queue_update_dma_alignment() later.
2036 blk_queue_dma_alignment(q, 0x03);
2039 struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost,
2040 request_fn_proc *request_fn)
2042 struct request_queue *q;
2044 q = blk_init_queue(request_fn, NULL);
2047 __scsi_init_queue(shost, q);
2050 EXPORT_SYMBOL(__scsi_alloc_queue);
2052 struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
2054 struct request_queue *q;
2056 q = __scsi_alloc_queue(sdev->host, scsi_request_fn);
2060 blk_queue_prep_rq(q, scsi_prep_fn);
2061 blk_queue_unprep_rq(q, scsi_unprep_fn);
2062 blk_queue_softirq_done(q, scsi_softirq_done);
2063 blk_queue_rq_timed_out(q, scsi_times_out);
2064 blk_queue_lld_busy(q, scsi_lld_busy);
2068 static struct blk_mq_ops scsi_mq_ops = {
2069 .map_queue = blk_mq_map_queue,
2070 .queue_rq = scsi_queue_rq,
2071 .complete = scsi_softirq_done,
2072 .timeout = scsi_timeout,
2073 .init_request = scsi_init_request,
2074 .exit_request = scsi_exit_request,
2077 struct request_queue *scsi_mq_alloc_queue(struct scsi_device *sdev)
2079 sdev->request_queue = blk_mq_init_queue(&sdev->host->tag_set);
2080 if (IS_ERR(sdev->request_queue))
2083 sdev->request_queue->queuedata = sdev;
2084 __scsi_init_queue(sdev->host, sdev->request_queue);
2085 return sdev->request_queue;
2088 int scsi_mq_setup_tags(struct Scsi_Host *shost)
2090 unsigned int cmd_size, sgl_size, tbl_size;
2092 tbl_size = shost->sg_tablesize;
2093 if (tbl_size > SCSI_MAX_SG_SEGMENTS)
2094 tbl_size = SCSI_MAX_SG_SEGMENTS;
2095 sgl_size = tbl_size * sizeof(struct scatterlist);
2096 cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size;
2097 if (scsi_host_get_prot(shost))
2098 cmd_size += sizeof(struct scsi_data_buffer) + sgl_size;
2100 memset(&shost->tag_set, 0, sizeof(shost->tag_set));
2101 shost->tag_set.ops = &scsi_mq_ops;
2102 shost->tag_set.nr_hw_queues = shost->nr_hw_queues ? : 1;
2103 shost->tag_set.queue_depth = shost->can_queue;
2104 shost->tag_set.cmd_size = cmd_size;
2105 shost->tag_set.numa_node = NUMA_NO_NODE;
2106 shost->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
2107 shost->tag_set.driver_data = shost;
2109 return blk_mq_alloc_tag_set(&shost->tag_set);
2112 void scsi_mq_destroy_tags(struct Scsi_Host *shost)
2114 blk_mq_free_tag_set(&shost->tag_set);
2118 * Function: scsi_block_requests()
2120 * Purpose: Utility function used by low-level drivers to prevent further
2121 * commands from being queued to the device.
2123 * Arguments: shost - Host in question
2127 * Lock status: No locks are assumed held.
2129 * Notes: There is no timer nor any other means by which the requests
2130 * get unblocked other than the low-level driver calling
2131 * scsi_unblock_requests().
2133 void scsi_block_requests(struct Scsi_Host *shost)
2135 shost->host_self_blocked = 1;
2137 EXPORT_SYMBOL(scsi_block_requests);
2140 * Function: scsi_unblock_requests()
2142 * Purpose: Utility function used by low-level drivers to allow further
2143 * commands from being queued to the device.
2145 * Arguments: shost - Host in question
2149 * Lock status: No locks are assumed held.
2151 * Notes: There is no timer nor any other means by which the requests
2152 * get unblocked other than the low-level driver calling
2153 * scsi_unblock_requests().
2155 * This is done as an API function so that changes to the
2156 * internals of the scsi mid-layer won't require wholesale
2157 * changes to drivers that use this feature.
2159 void scsi_unblock_requests(struct Scsi_Host *shost)
2161 shost->host_self_blocked = 0;
2162 scsi_run_host_queues(shost);
2164 EXPORT_SYMBOL(scsi_unblock_requests);
2166 int __init scsi_init_queue(void)
2170 scsi_sdb_cache = kmem_cache_create("scsi_data_buffer",
2171 sizeof(struct scsi_data_buffer),
2173 if (!scsi_sdb_cache) {
2174 printk(KERN_ERR "SCSI: can't init scsi sdb cache\n");
2178 for (i = 0; i < SG_MEMPOOL_NR; i++) {
2179 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
2180 int size = sgp->size * sizeof(struct scatterlist);
2182 sgp->slab = kmem_cache_create(sgp->name, size, 0,
2183 SLAB_HWCACHE_ALIGN, NULL);
2185 printk(KERN_ERR "SCSI: can't init sg slab %s\n",
2190 sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE,
2193 printk(KERN_ERR "SCSI: can't init sg mempool %s\n",
2202 for (i = 0; i < SG_MEMPOOL_NR; i++) {
2203 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
2205 mempool_destroy(sgp->pool);
2207 kmem_cache_destroy(sgp->slab);
2209 kmem_cache_destroy(scsi_sdb_cache);
2214 void scsi_exit_queue(void)
2218 kmem_cache_destroy(scsi_sdb_cache);
2220 for (i = 0; i < SG_MEMPOOL_NR; i++) {
2221 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
2222 mempool_destroy(sgp->pool);
2223 kmem_cache_destroy(sgp->slab);
2228 * scsi_mode_select - issue a mode select
2229 * @sdev: SCSI device to be queried
2230 * @pf: Page format bit (1 == standard, 0 == vendor specific)
2231 * @sp: Save page bit (0 == don't save, 1 == save)
2232 * @modepage: mode page being requested
2233 * @buffer: request buffer (may not be smaller than eight bytes)
2234 * @len: length of request buffer.
2235 * @timeout: command timeout
2236 * @retries: number of retries before failing
2237 * @data: returns a structure abstracting the mode header data
2238 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2239 * must be SCSI_SENSE_BUFFERSIZE big.
2241 * Returns zero if successful; negative error number or scsi
2246 scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
2247 unsigned char *buffer, int len, int timeout, int retries,
2248 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2250 unsigned char cmd[10];
2251 unsigned char *real_buffer;
2254 memset(cmd, 0, sizeof(cmd));
2255 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
2257 if (sdev->use_10_for_ms) {
2260 real_buffer = kmalloc(8 + len, GFP_KERNEL);
2263 memcpy(real_buffer + 8, buffer, len);
2267 real_buffer[2] = data->medium_type;
2268 real_buffer[3] = data->device_specific;
2269 real_buffer[4] = data->longlba ? 0x01 : 0;
2271 real_buffer[6] = data->block_descriptor_length >> 8;
2272 real_buffer[7] = data->block_descriptor_length;
2274 cmd[0] = MODE_SELECT_10;
2278 if (len > 255 || data->block_descriptor_length > 255 ||
2282 real_buffer = kmalloc(4 + len, GFP_KERNEL);
2285 memcpy(real_buffer + 4, buffer, len);
2288 real_buffer[1] = data->medium_type;
2289 real_buffer[2] = data->device_specific;
2290 real_buffer[3] = data->block_descriptor_length;
2293 cmd[0] = MODE_SELECT;
2297 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
2298 sshdr, timeout, retries, NULL);
2302 EXPORT_SYMBOL_GPL(scsi_mode_select);
2305 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
2306 * @sdev: SCSI device to be queried
2307 * @dbd: set if mode sense will allow block descriptors to be returned
2308 * @modepage: mode page being requested
2309 * @buffer: request buffer (may not be smaller than eight bytes)
2310 * @len: length of request buffer.
2311 * @timeout: command timeout
2312 * @retries: number of retries before failing
2313 * @data: returns a structure abstracting the mode header data
2314 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2315 * must be SCSI_SENSE_BUFFERSIZE big.
2317 * Returns zero if unsuccessful, or the header offset (either 4
2318 * or 8 depending on whether a six or ten byte command was
2319 * issued) if successful.
2322 scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
2323 unsigned char *buffer, int len, int timeout, int retries,
2324 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2326 unsigned char cmd[12];
2330 struct scsi_sense_hdr my_sshdr;
2332 memset(data, 0, sizeof(*data));
2333 memset(&cmd[0], 0, 12);
2334 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
2337 /* caller might not be interested in sense, but we need it */
2342 use_10_for_ms = sdev->use_10_for_ms;
2344 if (use_10_for_ms) {
2348 cmd[0] = MODE_SENSE_10;
2355 cmd[0] = MODE_SENSE;
2360 memset(buffer, 0, len);
2362 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
2363 sshdr, timeout, retries, NULL);
2365 /* This code looks awful: what it's doing is making sure an
2366 * ILLEGAL REQUEST sense return identifies the actual command
2367 * byte as the problem. MODE_SENSE commands can return
2368 * ILLEGAL REQUEST if the code page isn't supported */
2370 if (use_10_for_ms && !scsi_status_is_good(result) &&
2371 (driver_byte(result) & DRIVER_SENSE)) {
2372 if (scsi_sense_valid(sshdr)) {
2373 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
2374 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
2376 * Invalid command operation code
2378 sdev->use_10_for_ms = 0;
2384 if(scsi_status_is_good(result)) {
2385 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
2386 (modepage == 6 || modepage == 8))) {
2387 /* Initio breakage? */
2390 data->medium_type = 0;
2391 data->device_specific = 0;
2393 data->block_descriptor_length = 0;
2394 } else if(use_10_for_ms) {
2395 data->length = buffer[0]*256 + buffer[1] + 2;
2396 data->medium_type = buffer[2];
2397 data->device_specific = buffer[3];
2398 data->longlba = buffer[4] & 0x01;
2399 data->block_descriptor_length = buffer[6]*256
2402 data->length = buffer[0] + 1;
2403 data->medium_type = buffer[1];
2404 data->device_specific = buffer[2];
2405 data->block_descriptor_length = buffer[3];
2407 data->header_length = header_length;
2412 EXPORT_SYMBOL(scsi_mode_sense);
2415 * scsi_test_unit_ready - test if unit is ready
2416 * @sdev: scsi device to change the state of.
2417 * @timeout: command timeout
2418 * @retries: number of retries before failing
2419 * @sshdr_external: Optional pointer to struct scsi_sense_hdr for
2420 * returning sense. Make sure that this is cleared before passing
2423 * Returns zero if unsuccessful or an error if TUR failed. For
2424 * removable media, UNIT_ATTENTION sets ->changed flag.
2427 scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2428 struct scsi_sense_hdr *sshdr_external)
2431 TEST_UNIT_READY, 0, 0, 0, 0, 0,
2433 struct scsi_sense_hdr *sshdr;
2436 if (!sshdr_external)
2437 sshdr = kzalloc(sizeof(*sshdr), GFP_KERNEL);
2439 sshdr = sshdr_external;
2441 /* try to eat the UNIT_ATTENTION if there are enough retries */
2443 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
2444 timeout, retries, NULL);
2445 if (sdev->removable && scsi_sense_valid(sshdr) &&
2446 sshdr->sense_key == UNIT_ATTENTION)
2448 } while (scsi_sense_valid(sshdr) &&
2449 sshdr->sense_key == UNIT_ATTENTION && --retries);
2451 if (!sshdr_external)
2455 EXPORT_SYMBOL(scsi_test_unit_ready);
2458 * scsi_device_set_state - Take the given device through the device state model.
2459 * @sdev: scsi device to change the state of.
2460 * @state: state to change to.
2462 * Returns zero if unsuccessful or an error if the requested
2463 * transition is illegal.
2466 scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2468 enum scsi_device_state oldstate = sdev->sdev_state;
2470 if (state == oldstate)
2476 case SDEV_CREATED_BLOCK:
2487 case SDEV_TRANSPORT_OFFLINE:
2500 case SDEV_TRANSPORT_OFFLINE:
2508 case SDEV_TRANSPORT_OFFLINE:
2523 case SDEV_CREATED_BLOCK:
2530 case SDEV_CREATED_BLOCK:
2545 case SDEV_TRANSPORT_OFFLINE:
2558 case SDEV_TRANSPORT_OFFLINE:
2560 case SDEV_CREATED_BLOCK:
2568 sdev->sdev_state = state;
2572 SCSI_LOG_ERROR_RECOVERY(1,
2573 sdev_printk(KERN_ERR, sdev,
2574 "Illegal state transition %s->%s",
2575 scsi_device_state_name(oldstate),
2576 scsi_device_state_name(state))
2580 EXPORT_SYMBOL(scsi_device_set_state);
2583 * sdev_evt_emit - emit a single SCSI device uevent
2584 * @sdev: associated SCSI device
2585 * @evt: event to emit
2587 * Send a single uevent (scsi_event) to the associated scsi_device.
2589 static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2594 switch (evt->evt_type) {
2595 case SDEV_EVT_MEDIA_CHANGE:
2596 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2598 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2599 envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2601 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2602 envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2604 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2605 envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2607 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2608 envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2610 case SDEV_EVT_LUN_CHANGE_REPORTED:
2611 envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2620 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2624 * sdev_evt_thread - send a uevent for each scsi event
2625 * @work: work struct for scsi_device
2627 * Dispatch queued events to their associated scsi_device kobjects
2630 void scsi_evt_thread(struct work_struct *work)
2632 struct scsi_device *sdev;
2633 enum scsi_device_event evt_type;
2634 LIST_HEAD(event_list);
2636 sdev = container_of(work, struct scsi_device, event_work);
2638 for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
2639 if (test_and_clear_bit(evt_type, sdev->pending_events))
2640 sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
2643 struct scsi_event *evt;
2644 struct list_head *this, *tmp;
2645 unsigned long flags;
2647 spin_lock_irqsave(&sdev->list_lock, flags);
2648 list_splice_init(&sdev->event_list, &event_list);
2649 spin_unlock_irqrestore(&sdev->list_lock, flags);
2651 if (list_empty(&event_list))
2654 list_for_each_safe(this, tmp, &event_list) {
2655 evt = list_entry(this, struct scsi_event, node);
2656 list_del(&evt->node);
2657 scsi_evt_emit(sdev, evt);
2664 * sdev_evt_send - send asserted event to uevent thread
2665 * @sdev: scsi_device event occurred on
2666 * @evt: event to send
2668 * Assert scsi device event asynchronously.
2670 void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2672 unsigned long flags;
2675 /* FIXME: currently this check eliminates all media change events
2676 * for polled devices. Need to update to discriminate between AN
2677 * and polled events */
2678 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2684 spin_lock_irqsave(&sdev->list_lock, flags);
2685 list_add_tail(&evt->node, &sdev->event_list);
2686 schedule_work(&sdev->event_work);
2687 spin_unlock_irqrestore(&sdev->list_lock, flags);
2689 EXPORT_SYMBOL_GPL(sdev_evt_send);
2692 * sdev_evt_alloc - allocate a new scsi event
2693 * @evt_type: type of event to allocate
2694 * @gfpflags: GFP flags for allocation
2696 * Allocates and returns a new scsi_event.
2698 struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2701 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2705 evt->evt_type = evt_type;
2706 INIT_LIST_HEAD(&evt->node);
2708 /* evt_type-specific initialization, if any */
2710 case SDEV_EVT_MEDIA_CHANGE:
2711 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2712 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2713 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2714 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2715 case SDEV_EVT_LUN_CHANGE_REPORTED:
2723 EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2726 * sdev_evt_send_simple - send asserted event to uevent thread
2727 * @sdev: scsi_device event occurred on
2728 * @evt_type: type of event to send
2729 * @gfpflags: GFP flags for allocation
2731 * Assert scsi device event asynchronously, given an event type.
2733 void sdev_evt_send_simple(struct scsi_device *sdev,
2734 enum scsi_device_event evt_type, gfp_t gfpflags)
2736 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2738 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2743 sdev_evt_send(sdev, evt);
2745 EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2748 * scsi_device_quiesce - Block user issued commands.
2749 * @sdev: scsi device to quiesce.
2751 * This works by trying to transition to the SDEV_QUIESCE state
2752 * (which must be a legal transition). When the device is in this
2753 * state, only special requests will be accepted, all others will
2754 * be deferred. Since special requests may also be requeued requests,
2755 * a successful return doesn't guarantee the device will be
2756 * totally quiescent.
2758 * Must be called with user context, may sleep.
2760 * Returns zero if unsuccessful or an error if not.
2763 scsi_device_quiesce(struct scsi_device *sdev)
2765 int err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2769 scsi_run_queue(sdev->request_queue);
2770 while (atomic_read(&sdev->device_busy)) {
2771 msleep_interruptible(200);
2772 scsi_run_queue(sdev->request_queue);
2776 EXPORT_SYMBOL(scsi_device_quiesce);
2779 * scsi_device_resume - Restart user issued commands to a quiesced device.
2780 * @sdev: scsi device to resume.
2782 * Moves the device from quiesced back to running and restarts the
2785 * Must be called with user context, may sleep.
2787 void scsi_device_resume(struct scsi_device *sdev)
2789 /* check if the device state was mutated prior to resume, and if
2790 * so assume the state is being managed elsewhere (for example
2791 * device deleted during suspend)
2793 if (sdev->sdev_state != SDEV_QUIESCE ||
2794 scsi_device_set_state(sdev, SDEV_RUNNING))
2796 scsi_run_queue(sdev->request_queue);
2798 EXPORT_SYMBOL(scsi_device_resume);
2801 device_quiesce_fn(struct scsi_device *sdev, void *data)
2803 scsi_device_quiesce(sdev);
2807 scsi_target_quiesce(struct scsi_target *starget)
2809 starget_for_each_device(starget, NULL, device_quiesce_fn);
2811 EXPORT_SYMBOL(scsi_target_quiesce);
2814 device_resume_fn(struct scsi_device *sdev, void *data)
2816 scsi_device_resume(sdev);
2820 scsi_target_resume(struct scsi_target *starget)
2822 starget_for_each_device(starget, NULL, device_resume_fn);
2824 EXPORT_SYMBOL(scsi_target_resume);
2827 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state
2828 * @sdev: device to block
2830 * Block request made by scsi lld's to temporarily stop all
2831 * scsi commands on the specified device. Called from interrupt
2832 * or normal process context.
2834 * Returns zero if successful or error if not
2837 * This routine transitions the device to the SDEV_BLOCK state
2838 * (which must be a legal transition). When the device is in this
2839 * state, all commands are deferred until the scsi lld reenables
2840 * the device with scsi_device_unblock or device_block_tmo fires.
2843 scsi_internal_device_block(struct scsi_device *sdev)
2845 struct request_queue *q = sdev->request_queue;
2846 unsigned long flags;
2849 err = scsi_device_set_state(sdev, SDEV_BLOCK);
2851 err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2858 * The device has transitioned to SDEV_BLOCK. Stop the
2859 * block layer from calling the midlayer with this device's
2863 blk_mq_stop_hw_queues(q);
2865 spin_lock_irqsave(q->queue_lock, flags);
2867 spin_unlock_irqrestore(q->queue_lock, flags);
2872 EXPORT_SYMBOL_GPL(scsi_internal_device_block);
2875 * scsi_internal_device_unblock - resume a device after a block request
2876 * @sdev: device to resume
2877 * @new_state: state to set devices to after unblocking
2879 * Called by scsi lld's or the midlayer to restart the device queue
2880 * for the previously suspended scsi device. Called from interrupt or
2881 * normal process context.
2883 * Returns zero if successful or error if not.
2886 * This routine transitions the device to the SDEV_RUNNING state
2887 * or to one of the offline states (which must be a legal transition)
2888 * allowing the midlayer to goose the queue for this device.
2891 scsi_internal_device_unblock(struct scsi_device *sdev,
2892 enum scsi_device_state new_state)
2894 struct request_queue *q = sdev->request_queue;
2895 unsigned long flags;
2898 * Try to transition the scsi device to SDEV_RUNNING or one of the
2899 * offlined states and goose the device queue if successful.
2901 if ((sdev->sdev_state == SDEV_BLOCK) ||
2902 (sdev->sdev_state == SDEV_TRANSPORT_OFFLINE))
2903 sdev->sdev_state = new_state;
2904 else if (sdev->sdev_state == SDEV_CREATED_BLOCK) {
2905 if (new_state == SDEV_TRANSPORT_OFFLINE ||
2906 new_state == SDEV_OFFLINE)
2907 sdev->sdev_state = new_state;
2909 sdev->sdev_state = SDEV_CREATED;
2910 } else if (sdev->sdev_state != SDEV_CANCEL &&
2911 sdev->sdev_state != SDEV_OFFLINE)
2915 blk_mq_start_stopped_hw_queues(q, false);
2917 spin_lock_irqsave(q->queue_lock, flags);
2919 spin_unlock_irqrestore(q->queue_lock, flags);
2924 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock);
2927 device_block(struct scsi_device *sdev, void *data)
2929 scsi_internal_device_block(sdev);
2933 target_block(struct device *dev, void *data)
2935 if (scsi_is_target_device(dev))
2936 starget_for_each_device(to_scsi_target(dev), NULL,
2942 scsi_target_block(struct device *dev)
2944 if (scsi_is_target_device(dev))
2945 starget_for_each_device(to_scsi_target(dev), NULL,
2948 device_for_each_child(dev, NULL, target_block);
2950 EXPORT_SYMBOL_GPL(scsi_target_block);
2953 device_unblock(struct scsi_device *sdev, void *data)
2955 scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
2959 target_unblock(struct device *dev, void *data)
2961 if (scsi_is_target_device(dev))
2962 starget_for_each_device(to_scsi_target(dev), data,
2968 scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
2970 if (scsi_is_target_device(dev))
2971 starget_for_each_device(to_scsi_target(dev), &new_state,
2974 device_for_each_child(dev, &new_state, target_unblock);
2976 EXPORT_SYMBOL_GPL(scsi_target_unblock);
2979 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
2980 * @sgl: scatter-gather list
2981 * @sg_count: number of segments in sg
2982 * @offset: offset in bytes into sg, on return offset into the mapped area
2983 * @len: bytes to map, on return number of bytes mapped
2985 * Returns virtual address of the start of the mapped page
2987 void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
2988 size_t *offset, size_t *len)
2991 size_t sg_len = 0, len_complete = 0;
2992 struct scatterlist *sg;
2995 WARN_ON(!irqs_disabled());
2997 for_each_sg(sgl, sg, sg_count, i) {
2998 len_complete = sg_len; /* Complete sg-entries */
2999 sg_len += sg->length;
3000 if (sg_len > *offset)
3004 if (unlikely(i == sg_count)) {
3005 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
3007 __func__, sg_len, *offset, sg_count);
3012 /* Offset starting from the beginning of first page in this sg-entry */
3013 *offset = *offset - len_complete + sg->offset;
3015 /* Assumption: contiguous pages can be accessed as "page + i" */
3016 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
3017 *offset &= ~PAGE_MASK;
3019 /* Bytes in this sg-entry from *offset to the end of the page */
3020 sg_len = PAGE_SIZE - *offset;
3024 return kmap_atomic(page);
3026 EXPORT_SYMBOL(scsi_kmap_atomic_sg);
3029 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
3030 * @virt: virtual address to be unmapped
3032 void scsi_kunmap_atomic_sg(void *virt)
3034 kunmap_atomic(virt);
3036 EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
3038 void sdev_disable_disk_events(struct scsi_device *sdev)
3040 atomic_inc(&sdev->disk_events_disable_depth);
3042 EXPORT_SYMBOL(sdev_disable_disk_events);
3044 void sdev_enable_disk_events(struct scsi_device *sdev)
3046 if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0))
3048 atomic_dec(&sdev->disk_events_disable_depth);
3050 EXPORT_SYMBOL(sdev_enable_disk_events);