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 inline struct kmem_cache *
48 scsi_select_sense_cache(bool unchecked_isa_dma)
50 return unchecked_isa_dma ? scsi_sense_isadma_cache : scsi_sense_cache;
53 static void scsi_free_sense_buffer(bool unchecked_isa_dma,
54 unsigned char *sense_buffer)
56 kmem_cache_free(scsi_select_sense_cache(unchecked_isa_dma),
60 static unsigned char *scsi_alloc_sense_buffer(bool unchecked_isa_dma,
61 gfp_t gfp_mask, int numa_node)
63 return kmem_cache_alloc_node(scsi_select_sense_cache(unchecked_isa_dma),
67 int scsi_init_sense_cache(struct Scsi_Host *shost)
69 struct kmem_cache *cache;
72 cache = scsi_select_sense_cache(shost->unchecked_isa_dma);
76 mutex_lock(&scsi_sense_cache_mutex);
77 if (shost->unchecked_isa_dma) {
78 scsi_sense_isadma_cache =
79 kmem_cache_create("scsi_sense_cache(DMA)",
80 SCSI_SENSE_BUFFERSIZE, 0,
81 SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA, NULL);
82 if (!scsi_sense_isadma_cache)
86 kmem_cache_create("scsi_sense_cache",
87 SCSI_SENSE_BUFFERSIZE, 0, SLAB_HWCACHE_ALIGN, NULL);
88 if (!scsi_sense_cache)
92 mutex_unlock(&scsi_sense_cache_mutex);
97 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
98 * not change behaviour from the previous unplug mechanism, experimentation
99 * may prove this needs changing.
101 #define SCSI_QUEUE_DELAY 3
104 scsi_set_blocked(struct scsi_cmnd *cmd, int reason)
106 struct Scsi_Host *host = cmd->device->host;
107 struct scsi_device *device = cmd->device;
108 struct scsi_target *starget = scsi_target(device);
111 * Set the appropriate busy bit for the device/host.
113 * If the host/device isn't busy, assume that something actually
114 * completed, and that we should be able to queue a command now.
116 * Note that the prior mid-layer assumption that any host could
117 * always queue at least one command is now broken. The mid-layer
118 * will implement a user specifiable stall (see
119 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
120 * if a command is requeued with no other commands outstanding
121 * either for the device or for the host.
124 case SCSI_MLQUEUE_HOST_BUSY:
125 atomic_set(&host->host_blocked, host->max_host_blocked);
127 case SCSI_MLQUEUE_DEVICE_BUSY:
128 case SCSI_MLQUEUE_EH_RETRY:
129 atomic_set(&device->device_blocked,
130 device->max_device_blocked);
132 case SCSI_MLQUEUE_TARGET_BUSY:
133 atomic_set(&starget->target_blocked,
134 starget->max_target_blocked);
139 static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd)
141 struct scsi_device *sdev = cmd->device;
143 blk_mq_requeue_request(cmd->request, true);
144 put_device(&sdev->sdev_gendev);
148 * __scsi_queue_insert - private queue insertion
149 * @cmd: The SCSI command being requeued
150 * @reason: The reason for the requeue
151 * @unbusy: Whether the queue should be unbusied
153 * This is a private queue insertion. The public interface
154 * scsi_queue_insert() always assumes the queue should be unbusied
155 * because it's always called before the completion. This function is
156 * for a requeue after completion, which should only occur in this
159 static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy)
161 struct scsi_device *device = cmd->device;
162 struct request_queue *q = device->request_queue;
165 SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd,
166 "Inserting command %p into mlqueue\n", cmd));
168 scsi_set_blocked(cmd, reason);
171 * Decrement the counters, since these commands are no longer
172 * active on the host/device.
175 scsi_device_unbusy(device);
178 * Requeue this command. It will go before all other commands
179 * that are already in the queue. Schedule requeue work under
180 * lock such that the kblockd_schedule_work() call happens
181 * before blk_cleanup_queue() finishes.
185 scsi_mq_requeue_cmd(cmd);
188 spin_lock_irqsave(q->queue_lock, flags);
189 blk_requeue_request(q, cmd->request);
190 kblockd_schedule_work(&device->requeue_work);
191 spin_unlock_irqrestore(q->queue_lock, flags);
195 * Function: scsi_queue_insert()
197 * Purpose: Insert a command in the midlevel queue.
199 * Arguments: cmd - command that we are adding to queue.
200 * reason - why we are inserting command to queue.
202 * Lock status: Assumed that lock is not held upon entry.
206 * Notes: We do this for one of two cases. Either the host is busy
207 * and it cannot accept any more commands for the time being,
208 * or the device returned QUEUE_FULL and can accept no more
210 * Notes: This could be called either from an interrupt context or a
211 * normal process context.
213 void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
215 __scsi_queue_insert(cmd, reason, 1);
220 * scsi_execute - insert request and wait for the result
223 * @data_direction: data direction
224 * @buffer: data buffer
225 * @bufflen: len of buffer
226 * @sense: optional sense buffer
227 * @sshdr: optional decoded sense header
228 * @timeout: request timeout in seconds
229 * @retries: number of times to retry request
230 * @flags: flags for ->cmd_flags
231 * @rq_flags: flags for ->rq_flags
232 * @resid: optional residual length
234 * Returns the scsi_cmnd result field if a command was executed, or a negative
235 * Linux error code if we didn't get that far.
237 int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
238 int data_direction, void *buffer, unsigned bufflen,
239 unsigned char *sense, struct scsi_sense_hdr *sshdr,
240 int timeout, int retries, u64 flags, req_flags_t rq_flags,
244 struct scsi_request *rq;
245 int ret = DRIVER_ERROR << 24;
247 req = blk_get_request(sdev->request_queue,
248 data_direction == DMA_TO_DEVICE ?
249 REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, __GFP_RECLAIM);
255 if (bufflen && blk_rq_map_kern(sdev->request_queue, req,
256 buffer, bufflen, __GFP_RECLAIM))
259 rq->cmd_len = COMMAND_SIZE(cmd[0]);
260 memcpy(rq->cmd, cmd, rq->cmd_len);
261 rq->retries = retries;
262 req->timeout = timeout;
263 req->cmd_flags |= flags;
264 req->rq_flags |= rq_flags | RQF_QUIET | RQF_PREEMPT;
267 * head injection *required* here otherwise quiesce won't work
269 blk_execute_rq(req->q, NULL, req, 1);
272 * Some devices (USB mass-storage in particular) may transfer
273 * garbage data together with a residue indicating that the data
274 * is invalid. Prevent the garbage from being misinterpreted
275 * and prevent security leaks by zeroing out the excess data.
277 if (unlikely(rq->resid_len > 0 && rq->resid_len <= bufflen))
278 memset(buffer + (bufflen - rq->resid_len), 0, rq->resid_len);
281 *resid = rq->resid_len;
282 if (sense && rq->sense_len)
283 memcpy(sense, rq->sense, SCSI_SENSE_BUFFERSIZE);
285 scsi_normalize_sense(rq->sense, rq->sense_len, sshdr);
288 blk_put_request(req);
292 EXPORT_SYMBOL(scsi_execute);
295 * Function: scsi_init_cmd_errh()
297 * Purpose: Initialize cmd fields related to error handling.
299 * Arguments: cmd - command that is ready to be queued.
301 * Notes: This function has the job of initializing a number of
302 * fields related to error handling. Typically this will
303 * be called once for each command, as required.
305 static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
307 cmd->serial_number = 0;
308 scsi_set_resid(cmd, 0);
309 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
310 if (cmd->cmd_len == 0)
311 cmd->cmd_len = scsi_command_size(cmd->cmnd);
314 void scsi_device_unbusy(struct scsi_device *sdev)
316 struct Scsi_Host *shost = sdev->host;
317 struct scsi_target *starget = scsi_target(sdev);
320 atomic_dec(&shost->host_busy);
321 if (starget->can_queue > 0)
322 atomic_dec(&starget->target_busy);
324 if (unlikely(scsi_host_in_recovery(shost) &&
325 (shost->host_failed || shost->host_eh_scheduled))) {
326 spin_lock_irqsave(shost->host_lock, flags);
327 scsi_eh_wakeup(shost);
328 spin_unlock_irqrestore(shost->host_lock, flags);
331 atomic_dec(&sdev->device_busy);
334 static void scsi_kick_queue(struct request_queue *q)
337 blk_mq_start_hw_queues(q);
343 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
344 * and call blk_run_queue for all the scsi_devices on the target -
345 * including current_sdev first.
347 * Called with *no* scsi locks held.
349 static void scsi_single_lun_run(struct scsi_device *current_sdev)
351 struct Scsi_Host *shost = current_sdev->host;
352 struct scsi_device *sdev, *tmp;
353 struct scsi_target *starget = scsi_target(current_sdev);
356 spin_lock_irqsave(shost->host_lock, flags);
357 starget->starget_sdev_user = NULL;
358 spin_unlock_irqrestore(shost->host_lock, flags);
361 * Call blk_run_queue for all LUNs on the target, starting with
362 * current_sdev. We race with others (to set starget_sdev_user),
363 * but in most cases, we will be first. Ideally, each LU on the
364 * target would get some limited time or requests on the target.
366 scsi_kick_queue(current_sdev->request_queue);
368 spin_lock_irqsave(shost->host_lock, flags);
369 if (starget->starget_sdev_user)
371 list_for_each_entry_safe(sdev, tmp, &starget->devices,
372 same_target_siblings) {
373 if (sdev == current_sdev)
375 if (scsi_device_get(sdev))
378 spin_unlock_irqrestore(shost->host_lock, flags);
379 scsi_kick_queue(sdev->request_queue);
380 spin_lock_irqsave(shost->host_lock, flags);
382 scsi_device_put(sdev);
385 spin_unlock_irqrestore(shost->host_lock, flags);
388 static inline bool scsi_device_is_busy(struct scsi_device *sdev)
390 if (atomic_read(&sdev->device_busy) >= sdev->queue_depth)
392 if (atomic_read(&sdev->device_blocked) > 0)
397 static inline bool scsi_target_is_busy(struct scsi_target *starget)
399 if (starget->can_queue > 0) {
400 if (atomic_read(&starget->target_busy) >= starget->can_queue)
402 if (atomic_read(&starget->target_blocked) > 0)
408 static inline bool scsi_host_is_busy(struct Scsi_Host *shost)
410 if (shost->can_queue > 0 &&
411 atomic_read(&shost->host_busy) >= shost->can_queue)
413 if (atomic_read(&shost->host_blocked) > 0)
415 if (shost->host_self_blocked)
420 static void scsi_starved_list_run(struct Scsi_Host *shost)
422 LIST_HEAD(starved_list);
423 struct scsi_device *sdev;
426 spin_lock_irqsave(shost->host_lock, flags);
427 list_splice_init(&shost->starved_list, &starved_list);
429 while (!list_empty(&starved_list)) {
430 struct request_queue *slq;
433 * As long as shost is accepting commands and we have
434 * starved queues, call blk_run_queue. scsi_request_fn
435 * drops the queue_lock and can add us back to the
438 * host_lock protects the starved_list and starved_entry.
439 * scsi_request_fn must get the host_lock before checking
440 * or modifying starved_list or starved_entry.
442 if (scsi_host_is_busy(shost))
445 sdev = list_entry(starved_list.next,
446 struct scsi_device, starved_entry);
447 list_del_init(&sdev->starved_entry);
448 if (scsi_target_is_busy(scsi_target(sdev))) {
449 list_move_tail(&sdev->starved_entry,
450 &shost->starved_list);
455 * Once we drop the host lock, a racing scsi_remove_device()
456 * call may remove the sdev from the starved list and destroy
457 * it and the queue. Mitigate by taking a reference to the
458 * queue and never touching the sdev again after we drop the
459 * host lock. Note: if __scsi_remove_device() invokes
460 * blk_cleanup_queue() before the queue is run from this
461 * function then blk_run_queue() will return immediately since
462 * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING.
464 slq = sdev->request_queue;
465 if (!blk_get_queue(slq))
467 spin_unlock_irqrestore(shost->host_lock, flags);
469 scsi_kick_queue(slq);
472 spin_lock_irqsave(shost->host_lock, flags);
474 /* put any unprocessed entries back */
475 list_splice(&starved_list, &shost->starved_list);
476 spin_unlock_irqrestore(shost->host_lock, flags);
480 * Function: scsi_run_queue()
482 * Purpose: Select a proper request queue to serve next
484 * Arguments: q - last request's queue
488 * Notes: The previous command was completely finished, start
489 * a new one if possible.
491 static void scsi_run_queue(struct request_queue *q)
493 struct scsi_device *sdev = q->queuedata;
495 if (scsi_target(sdev)->single_lun)
496 scsi_single_lun_run(sdev);
497 if (!list_empty(&sdev->host->starved_list))
498 scsi_starved_list_run(sdev->host);
501 blk_mq_run_hw_queues(q, false);
506 void scsi_requeue_run_queue(struct work_struct *work)
508 struct scsi_device *sdev;
509 struct request_queue *q;
511 sdev = container_of(work, struct scsi_device, requeue_work);
512 q = sdev->request_queue;
517 * Function: scsi_requeue_command()
519 * Purpose: Handle post-processing of completed commands.
521 * Arguments: q - queue to operate on
522 * cmd - command that may need to be requeued.
526 * Notes: After command completion, there may be blocks left
527 * over which weren't finished by the previous command
528 * this can be for a number of reasons - the main one is
529 * I/O errors in the middle of the request, in which case
530 * we need to request the blocks that come after the bad
532 * Notes: Upon return, cmd is a stale pointer.
534 static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd)
536 struct scsi_device *sdev = cmd->device;
537 struct request *req = cmd->request;
540 spin_lock_irqsave(q->queue_lock, flags);
541 blk_unprep_request(req);
543 scsi_put_command(cmd);
544 blk_requeue_request(q, req);
545 spin_unlock_irqrestore(q->queue_lock, flags);
549 put_device(&sdev->sdev_gendev);
552 void scsi_run_host_queues(struct Scsi_Host *shost)
554 struct scsi_device *sdev;
556 shost_for_each_device(sdev, shost)
557 scsi_run_queue(sdev->request_queue);
560 static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
562 if (!blk_rq_is_passthrough(cmd->request)) {
563 struct scsi_driver *drv = scsi_cmd_to_driver(cmd);
565 if (drv->uninit_command)
566 drv->uninit_command(cmd);
570 static void scsi_mq_free_sgtables(struct scsi_cmnd *cmd)
572 struct scsi_data_buffer *sdb;
574 if (cmd->sdb.table.nents)
575 sg_free_table_chained(&cmd->sdb.table, true);
576 if (cmd->request->next_rq) {
577 sdb = cmd->request->next_rq->special;
579 sg_free_table_chained(&sdb->table, true);
581 if (scsi_prot_sg_count(cmd))
582 sg_free_table_chained(&cmd->prot_sdb->table, true);
585 static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
587 struct scsi_device *sdev = cmd->device;
588 struct Scsi_Host *shost = sdev->host;
591 scsi_mq_free_sgtables(cmd);
592 scsi_uninit_cmd(cmd);
594 if (shost->use_cmd_list) {
595 BUG_ON(list_empty(&cmd->list));
596 spin_lock_irqsave(&sdev->list_lock, flags);
597 list_del_init(&cmd->list);
598 spin_unlock_irqrestore(&sdev->list_lock, flags);
603 * Function: scsi_release_buffers()
605 * Purpose: Free resources allocate for a scsi_command.
607 * Arguments: cmd - command that we are bailing.
609 * Lock status: Assumed that no lock is held upon entry.
613 * Notes: In the event that an upper level driver rejects a
614 * command, we must release resources allocated during
615 * the __init_io() function. Primarily this would involve
616 * the scatter-gather table.
618 static void scsi_release_buffers(struct scsi_cmnd *cmd)
620 if (cmd->sdb.table.nents)
621 sg_free_table_chained(&cmd->sdb.table, false);
623 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
625 if (scsi_prot_sg_count(cmd))
626 sg_free_table_chained(&cmd->prot_sdb->table, false);
629 static void scsi_release_bidi_buffers(struct scsi_cmnd *cmd)
631 struct scsi_data_buffer *bidi_sdb = cmd->request->next_rq->special;
633 sg_free_table_chained(&bidi_sdb->table, false);
634 kmem_cache_free(scsi_sdb_cache, bidi_sdb);
635 cmd->request->next_rq->special = NULL;
638 static bool scsi_end_request(struct request *req, int error,
639 unsigned int bytes, unsigned int bidi_bytes)
641 struct scsi_cmnd *cmd = req->special;
642 struct scsi_device *sdev = cmd->device;
643 struct request_queue *q = sdev->request_queue;
645 if (blk_update_request(req, error, bytes))
648 /* Bidi request must be completed as a whole */
649 if (unlikely(bidi_bytes) &&
650 blk_update_request(req->next_rq, error, bidi_bytes))
653 if (blk_queue_add_random(q))
654 add_disk_randomness(req->rq_disk);
658 * In the MQ case the command gets freed by __blk_mq_end_request,
659 * so we have to do all cleanup that depends on it earlier.
661 * We also can't kick the queues from irq context, so we
662 * will have to defer it to a workqueue.
664 scsi_mq_uninit_cmd(cmd);
666 __blk_mq_end_request(req, error);
668 if (scsi_target(sdev)->single_lun ||
669 !list_empty(&sdev->host->starved_list))
670 kblockd_schedule_work(&sdev->requeue_work);
672 blk_mq_run_hw_queues(q, true);
677 scsi_release_bidi_buffers(cmd);
678 scsi_release_buffers(cmd);
679 scsi_put_command(cmd);
681 spin_lock_irqsave(q->queue_lock, flags);
682 blk_finish_request(req, error);
683 spin_unlock_irqrestore(q->queue_lock, flags);
688 put_device(&sdev->sdev_gendev);
693 * __scsi_error_from_host_byte - translate SCSI error code into errno
694 * @cmd: SCSI command (unused)
695 * @result: scsi error code
697 * Translate SCSI error code into standard UNIX errno.
699 * -ENOLINK temporary transport failure
700 * -EREMOTEIO permanent target failure, do not retry
701 * -EBADE permanent nexus failure, retry on other path
702 * -ENOSPC No write space available
703 * -ENODATA Medium error
704 * -EIO unspecified I/O error
706 static int __scsi_error_from_host_byte(struct scsi_cmnd *cmd, int result)
710 switch(host_byte(result)) {
711 case DID_TRANSPORT_FAILFAST:
714 case DID_TARGET_FAILURE:
715 set_host_byte(cmd, DID_OK);
718 case DID_NEXUS_FAILURE:
719 set_host_byte(cmd, DID_OK);
722 case DID_ALLOC_FAILURE:
723 set_host_byte(cmd, DID_OK);
726 case DID_MEDIUM_ERROR:
727 set_host_byte(cmd, DID_OK);
739 * Function: scsi_io_completion()
741 * Purpose: Completion processing for block device I/O requests.
743 * Arguments: cmd - command that is finished.
745 * Lock status: Assumed that no lock is held upon entry.
749 * Notes: We will finish off the specified number of sectors. If we
750 * are done, the command block will be released and the queue
751 * function will be goosed. If we are not done then we have to
752 * figure out what to do next:
754 * a) We can call scsi_requeue_command(). The request
755 * will be unprepared and put back on the queue. Then
756 * a new command will be created for it. This should
757 * be used if we made forward progress, or if we want
758 * to switch from READ(10) to READ(6) for example.
760 * b) We can call __scsi_queue_insert(). The request will
761 * be put back on the queue and retried using the same
762 * command as before, possibly after a delay.
764 * c) We can call scsi_end_request() with -EIO to fail
765 * the remainder of the request.
767 void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
769 int result = cmd->result;
770 struct request_queue *q = cmd->device->request_queue;
771 struct request *req = cmd->request;
773 struct scsi_sense_hdr sshdr;
774 bool sense_valid = false;
775 int sense_deferred = 0, level = 0;
776 enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,
777 ACTION_DELAYED_RETRY} action;
778 unsigned long wait_for = (cmd->allowed + 1) * req->timeout;
781 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
783 sense_deferred = scsi_sense_is_deferred(&sshdr);
786 if (blk_rq_is_passthrough(req)) {
790 * SG_IO wants current and deferred errors
792 scsi_req(req)->sense_len =
793 min(8 + cmd->sense_buffer[7],
794 SCSI_SENSE_BUFFERSIZE);
797 error = __scsi_error_from_host_byte(cmd, result);
800 * __scsi_error_from_host_byte may have reset the host_byte
802 scsi_req(req)->result = cmd->result;
803 scsi_req(req)->resid_len = scsi_get_resid(cmd);
805 if (scsi_bidi_cmnd(cmd)) {
807 * Bidi commands Must be complete as a whole,
808 * both sides at once.
810 scsi_req(req->next_rq)->resid_len = scsi_in(cmd)->resid;
811 if (scsi_end_request(req, 0, blk_rq_bytes(req),
812 blk_rq_bytes(req->next_rq)))
816 } else if (blk_rq_bytes(req) == 0 && result && !sense_deferred) {
818 * Flush commands do not transfers any data, and thus cannot use
819 * good_bytes != blk_rq_bytes(req) as the signal for an error.
820 * This sets the error explicitly for the problem case.
822 error = __scsi_error_from_host_byte(cmd, result);
825 /* no bidi support for !blk_rq_is_passthrough yet */
826 BUG_ON(blk_bidi_rq(req));
829 * Next deal with any sectors which we were able to correctly
832 SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd,
833 "%u sectors total, %d bytes done.\n",
834 blk_rq_sectors(req), good_bytes));
837 * Recovered errors need reporting, but they're always treated as
838 * success, so fiddle the result code here. For passthrough requests
839 * we already took a copy of the original into sreq->result which
840 * is what gets returned to the user
842 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
843 /* if ATA PASS-THROUGH INFORMATION AVAILABLE skip
844 * print since caller wants ATA registers. Only occurs on
845 * SCSI ATA PASS_THROUGH commands when CK_COND=1
847 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
849 else if (!(req->rq_flags & RQF_QUIET))
850 scsi_print_sense(cmd);
852 /* for passthrough error may be set */
857 * special case: failed zero length commands always need to
858 * drop down into the retry code. Otherwise, if we finished
859 * all bytes in the request we are done now.
861 if (!(blk_rq_bytes(req) == 0 && error) &&
862 !scsi_end_request(req, error, good_bytes, 0))
866 * Kill remainder if no retrys.
868 if (error && scsi_noretry_cmd(cmd)) {
869 if (scsi_end_request(req, error, blk_rq_bytes(req), 0))
875 * If there had been no error, but we have leftover bytes in the
876 * requeues just queue the command up again.
881 error = __scsi_error_from_host_byte(cmd, result);
883 if (host_byte(result) == DID_RESET) {
884 /* Third party bus reset or reset for error recovery
885 * reasons. Just retry the command and see what
888 action = ACTION_RETRY;
889 } else if (sense_valid && !sense_deferred) {
890 switch (sshdr.sense_key) {
892 if (cmd->device->removable) {
893 /* Detected disc change. Set a bit
894 * and quietly refuse further access.
896 cmd->device->changed = 1;
897 action = ACTION_FAIL;
899 /* Must have been a power glitch, or a
900 * bus reset. Could not have been a
901 * media change, so we just retry the
902 * command and see what happens.
904 action = ACTION_RETRY;
907 case ILLEGAL_REQUEST:
908 /* If we had an ILLEGAL REQUEST returned, then
909 * we may have performed an unsupported
910 * command. The only thing this should be
911 * would be a ten byte read where only a six
912 * byte read was supported. Also, on a system
913 * where READ CAPACITY failed, we may have
914 * read past the end of the disk.
916 if ((cmd->device->use_10_for_rw &&
917 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
918 (cmd->cmnd[0] == READ_10 ||
919 cmd->cmnd[0] == WRITE_10)) {
920 /* This will issue a new 6-byte command. */
921 cmd->device->use_10_for_rw = 0;
922 action = ACTION_REPREP;
923 } else if (sshdr.asc == 0x10) /* DIX */ {
924 action = ACTION_FAIL;
926 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
927 } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
928 action = ACTION_FAIL;
931 action = ACTION_FAIL;
933 case ABORTED_COMMAND:
934 action = ACTION_FAIL;
935 if (sshdr.asc == 0x10) /* DIF */
939 /* If the device is in the process of becoming
940 * ready, or has a temporary blockage, retry.
942 if (sshdr.asc == 0x04) {
943 switch (sshdr.ascq) {
944 case 0x01: /* becoming ready */
945 case 0x04: /* format in progress */
946 case 0x05: /* rebuild in progress */
947 case 0x06: /* recalculation in progress */
948 case 0x07: /* operation in progress */
949 case 0x08: /* Long write in progress */
950 case 0x09: /* self test in progress */
951 case 0x14: /* space allocation in progress */
952 action = ACTION_DELAYED_RETRY;
955 action = ACTION_FAIL;
959 action = ACTION_FAIL;
961 case VOLUME_OVERFLOW:
962 /* See SSC3rXX or current. */
963 action = ACTION_FAIL;
966 action = ACTION_FAIL;
970 action = ACTION_FAIL;
972 if (action != ACTION_FAIL &&
973 time_before(cmd->jiffies_at_alloc + wait_for, jiffies))
974 action = ACTION_FAIL;
978 /* Give up and fail the remainder of the request */
979 if (!(req->rq_flags & RQF_QUIET)) {
980 static DEFINE_RATELIMIT_STATE(_rs,
981 DEFAULT_RATELIMIT_INTERVAL,
982 DEFAULT_RATELIMIT_BURST);
984 if (unlikely(scsi_logging_level))
985 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
986 SCSI_LOG_MLCOMPLETE_BITS);
989 * if logging is enabled the failure will be printed
990 * in scsi_log_completion(), so avoid duplicate messages
992 if (!level && __ratelimit(&_rs)) {
993 scsi_print_result(cmd, NULL, FAILED);
994 if (driver_byte(result) & DRIVER_SENSE)
995 scsi_print_sense(cmd);
996 scsi_print_command(cmd);
999 if (!scsi_end_request(req, error, blk_rq_err_bytes(req), 0))
1004 /* Unprep the request and put it back at the head of the queue.
1005 * A new command will be prepared and issued.
1008 cmd->request->rq_flags &= ~RQF_DONTPREP;
1009 scsi_mq_uninit_cmd(cmd);
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);
1137 void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd)
1139 void *buf = cmd->sense_buffer;
1140 void *prot = cmd->prot_sdb;
1141 unsigned int unchecked_isa_dma = cmd->flags & SCMD_UNCHECKED_ISA_DMA;
1142 unsigned long flags;
1144 /* zero out the cmd, except for the embedded scsi_request */
1145 memset((char *)cmd + sizeof(cmd->req), 0,
1146 sizeof(*cmd) - sizeof(cmd->req) + dev->host->hostt->cmd_size);
1149 cmd->sense_buffer = buf;
1150 cmd->prot_sdb = prot;
1151 cmd->flags = unchecked_isa_dma;
1152 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
1153 cmd->jiffies_at_alloc = jiffies;
1155 spin_lock_irqsave(&dev->list_lock, flags);
1156 list_add_tail(&cmd->list, &dev->cmd_list);
1157 spin_unlock_irqrestore(&dev->list_lock, flags);
1160 static int scsi_setup_scsi_cmnd(struct scsi_device *sdev, struct request *req)
1162 struct scsi_cmnd *cmd = req->special;
1165 * Passthrough requests may transfer data, in which case they must
1166 * a bio attached to them. Or they might contain a SCSI command
1167 * that does not transfer data, in which case they may optionally
1168 * submit a request without an attached bio.
1171 int ret = scsi_init_io(cmd);
1175 BUG_ON(blk_rq_bytes(req));
1177 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1180 cmd->cmd_len = scsi_req(req)->cmd_len;
1181 cmd->cmnd = scsi_req(req)->cmd;
1182 cmd->transfersize = blk_rq_bytes(req);
1183 cmd->allowed = scsi_req(req)->retries;
1188 * Setup a normal block command. These are simple request from filesystems
1189 * that still need to be translated to SCSI CDBs from the ULD.
1191 static int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
1193 struct scsi_cmnd *cmd = req->special;
1195 if (unlikely(sdev->handler && sdev->handler->prep_fn)) {
1196 int ret = sdev->handler->prep_fn(sdev, req);
1197 if (ret != BLKPREP_OK)
1201 cmd->cmnd = scsi_req(req)->cmd = scsi_req(req)->__cmd;
1202 memset(cmd->cmnd, 0, BLK_MAX_CDB);
1203 return scsi_cmd_to_driver(cmd)->init_command(cmd);
1206 static int scsi_setup_cmnd(struct scsi_device *sdev, struct request *req)
1208 struct scsi_cmnd *cmd = req->special;
1210 if (!blk_rq_bytes(req))
1211 cmd->sc_data_direction = DMA_NONE;
1212 else if (rq_data_dir(req) == WRITE)
1213 cmd->sc_data_direction = DMA_TO_DEVICE;
1215 cmd->sc_data_direction = DMA_FROM_DEVICE;
1217 if (blk_rq_is_scsi(req))
1218 return scsi_setup_scsi_cmnd(sdev, req);
1220 return scsi_setup_fs_cmnd(sdev, req);
1224 scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
1226 int ret = BLKPREP_OK;
1229 * If the device is not in running state we will reject some
1232 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
1233 switch (sdev->sdev_state) {
1235 case SDEV_TRANSPORT_OFFLINE:
1237 * If the device is offline we refuse to process any
1238 * commands. The device must be brought online
1239 * before trying any recovery commands.
1241 sdev_printk(KERN_ERR, sdev,
1242 "rejecting I/O to offline device\n");
1247 * If the device is fully deleted, we refuse to
1248 * process any commands as well.
1250 sdev_printk(KERN_ERR, sdev,
1251 "rejecting I/O to dead device\n");
1255 case SDEV_CREATED_BLOCK:
1256 ret = BLKPREP_DEFER;
1260 * If the devices is blocked we defer normal commands.
1262 if (!(req->rq_flags & RQF_PREEMPT))
1263 ret = BLKPREP_DEFER;
1267 * For any other not fully online state we only allow
1268 * special commands. In particular any user initiated
1269 * command is not allowed.
1271 if (!(req->rq_flags & RQF_PREEMPT))
1280 scsi_prep_return(struct request_queue *q, struct request *req, int ret)
1282 struct scsi_device *sdev = q->queuedata;
1286 case BLKPREP_INVALID:
1287 scsi_req(req)->result = DID_NO_CONNECT << 16;
1288 /* release the command and kill it */
1290 struct scsi_cmnd *cmd = req->special;
1291 scsi_release_buffers(cmd);
1292 scsi_put_command(cmd);
1293 put_device(&sdev->sdev_gendev);
1294 req->special = NULL;
1299 * If we defer, the blk_peek_request() returns NULL, but the
1300 * queue must be restarted, so we schedule a callback to happen
1303 if (atomic_read(&sdev->device_busy) == 0)
1304 blk_delay_queue(q, SCSI_QUEUE_DELAY);
1307 req->rq_flags |= RQF_DONTPREP;
1313 static int scsi_prep_fn(struct request_queue *q, struct request *req)
1315 struct scsi_device *sdev = q->queuedata;
1316 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1319 ret = scsi_prep_state_check(sdev, req);
1320 if (ret != BLKPREP_OK)
1323 if (!req->special) {
1324 /* Bail if we can't get a reference to the device */
1325 if (unlikely(!get_device(&sdev->sdev_gendev))) {
1326 ret = BLKPREP_DEFER;
1330 scsi_init_command(sdev, cmd);
1334 cmd->tag = req->tag;
1336 cmd->prot_op = SCSI_PROT_NORMAL;
1338 ret = scsi_setup_cmnd(sdev, req);
1340 return scsi_prep_return(q, req, ret);
1343 static void scsi_unprep_fn(struct request_queue *q, struct request *req)
1345 scsi_uninit_cmd(req->special);
1349 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1352 * Called with the queue_lock held.
1354 static inline int scsi_dev_queue_ready(struct request_queue *q,
1355 struct scsi_device *sdev)
1359 busy = atomic_inc_return(&sdev->device_busy) - 1;
1360 if (atomic_read(&sdev->device_blocked)) {
1365 * unblock after device_blocked iterates to zero
1367 if (atomic_dec_return(&sdev->device_blocked) > 0) {
1369 * For the MQ case we take care of this in the caller.
1372 blk_delay_queue(q, SCSI_QUEUE_DELAY);
1375 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev,
1376 "unblocking device at zero depth\n"));
1379 if (busy >= sdev->queue_depth)
1384 atomic_dec(&sdev->device_busy);
1389 * scsi_target_queue_ready: checks if there we can send commands to target
1390 * @sdev: scsi device on starget to check.
1392 static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1393 struct scsi_device *sdev)
1395 struct scsi_target *starget = scsi_target(sdev);
1398 if (starget->single_lun) {
1399 spin_lock_irq(shost->host_lock);
1400 if (starget->starget_sdev_user &&
1401 starget->starget_sdev_user != sdev) {
1402 spin_unlock_irq(shost->host_lock);
1405 starget->starget_sdev_user = sdev;
1406 spin_unlock_irq(shost->host_lock);
1409 if (starget->can_queue <= 0)
1412 busy = atomic_inc_return(&starget->target_busy) - 1;
1413 if (atomic_read(&starget->target_blocked) > 0) {
1418 * unblock after target_blocked iterates to zero
1420 if (atomic_dec_return(&starget->target_blocked) > 0)
1423 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1424 "unblocking target at zero depth\n"));
1427 if (busy >= starget->can_queue)
1433 spin_lock_irq(shost->host_lock);
1434 list_move_tail(&sdev->starved_entry, &shost->starved_list);
1435 spin_unlock_irq(shost->host_lock);
1437 if (starget->can_queue > 0)
1438 atomic_dec(&starget->target_busy);
1443 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1444 * return 0. We must end up running the queue again whenever 0 is
1445 * returned, else IO can hang.
1447 static inline int scsi_host_queue_ready(struct request_queue *q,
1448 struct Scsi_Host *shost,
1449 struct scsi_device *sdev)
1453 if (scsi_host_in_recovery(shost))
1456 busy = atomic_inc_return(&shost->host_busy) - 1;
1457 if (atomic_read(&shost->host_blocked) > 0) {
1462 * unblock after host_blocked iterates to zero
1464 if (atomic_dec_return(&shost->host_blocked) > 0)
1468 shost_printk(KERN_INFO, shost,
1469 "unblocking host at zero depth\n"));
1472 if (shost->can_queue > 0 && busy >= shost->can_queue)
1474 if (shost->host_self_blocked)
1477 /* We're OK to process the command, so we can't be starved */
1478 if (!list_empty(&sdev->starved_entry)) {
1479 spin_lock_irq(shost->host_lock);
1480 if (!list_empty(&sdev->starved_entry))
1481 list_del_init(&sdev->starved_entry);
1482 spin_unlock_irq(shost->host_lock);
1488 spin_lock_irq(shost->host_lock);
1489 if (list_empty(&sdev->starved_entry))
1490 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1491 spin_unlock_irq(shost->host_lock);
1493 atomic_dec(&shost->host_busy);
1498 * Busy state exporting function for request stacking drivers.
1500 * For efficiency, no lock is taken to check the busy state of
1501 * shost/starget/sdev, since the returned value is not guaranteed and
1502 * may be changed after request stacking drivers call the function,
1503 * regardless of taking lock or not.
1505 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1506 * needs to return 'not busy'. Otherwise, request stacking drivers
1507 * may hold requests forever.
1509 static int scsi_lld_busy(struct request_queue *q)
1511 struct scsi_device *sdev = q->queuedata;
1512 struct Scsi_Host *shost;
1514 if (blk_queue_dying(q))
1520 * Ignore host/starget busy state.
1521 * Since block layer does not have a concept of fairness across
1522 * multiple queues, congestion of host/starget needs to be handled
1525 if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
1532 * Kill a request for a dead device
1534 static void scsi_kill_request(struct request *req, struct request_queue *q)
1536 struct scsi_cmnd *cmd = req->special;
1537 struct scsi_device *sdev;
1538 struct scsi_target *starget;
1539 struct Scsi_Host *shost;
1541 blk_start_request(req);
1543 scmd_printk(KERN_INFO, cmd, "killing request\n");
1546 starget = scsi_target(sdev);
1548 scsi_init_cmd_errh(cmd);
1549 cmd->result = DID_NO_CONNECT << 16;
1550 atomic_inc(&cmd->device->iorequest_cnt);
1553 * SCSI request completion path will do scsi_device_unbusy(),
1554 * bump busy counts. To bump the counters, we need to dance
1555 * with the locks as normal issue path does.
1557 atomic_inc(&sdev->device_busy);
1558 atomic_inc(&shost->host_busy);
1559 if (starget->can_queue > 0)
1560 atomic_inc(&starget->target_busy);
1562 blk_complete_request(req);
1565 static void scsi_softirq_done(struct request *rq)
1567 struct scsi_cmnd *cmd = rq->special;
1568 unsigned long wait_for = (cmd->allowed + 1) * rq->timeout;
1571 INIT_LIST_HEAD(&cmd->eh_entry);
1573 atomic_inc(&cmd->device->iodone_cnt);
1575 atomic_inc(&cmd->device->ioerr_cnt);
1577 disposition = scsi_decide_disposition(cmd);
1578 if (disposition != SUCCESS &&
1579 time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
1580 sdev_printk(KERN_ERR, cmd->device,
1581 "timing out command, waited %lus\n",
1583 disposition = SUCCESS;
1586 scsi_log_completion(cmd, disposition);
1588 switch (disposition) {
1590 scsi_finish_command(cmd);
1593 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
1595 case ADD_TO_MLQUEUE:
1596 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1599 scsi_eh_scmd_add(cmd);
1605 * scsi_dispatch_command - Dispatch a command to the low-level driver.
1606 * @cmd: command block we are dispatching.
1608 * Return: nonzero return request was rejected and device's queue needs to be
1611 static int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
1613 struct Scsi_Host *host = cmd->device->host;
1616 atomic_inc(&cmd->device->iorequest_cnt);
1618 /* check if the device is still usable */
1619 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
1620 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
1621 * returns an immediate error upwards, and signals
1622 * that the device is no longer present */
1623 cmd->result = DID_NO_CONNECT << 16;
1627 /* Check to see if the scsi lld made this device blocked. */
1628 if (unlikely(scsi_device_blocked(cmd->device))) {
1630 * in blocked state, the command is just put back on
1631 * the device queue. The suspend state has already
1632 * blocked the queue so future requests should not
1633 * occur until the device transitions out of the
1636 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1637 "queuecommand : device blocked\n"));
1638 return SCSI_MLQUEUE_DEVICE_BUSY;
1641 /* Store the LUN value in cmnd, if needed. */
1642 if (cmd->device->lun_in_cdb)
1643 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
1644 (cmd->device->lun << 5 & 0xe0);
1649 * Before we queue this command, check if the command
1650 * length exceeds what the host adapter can handle.
1652 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
1653 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1654 "queuecommand : command too long. "
1655 "cdb_size=%d host->max_cmd_len=%d\n",
1656 cmd->cmd_len, cmd->device->host->max_cmd_len));
1657 cmd->result = (DID_ABORT << 16);
1661 if (unlikely(host->shost_state == SHOST_DEL)) {
1662 cmd->result = (DID_NO_CONNECT << 16);
1667 trace_scsi_dispatch_cmd_start(cmd);
1668 rtn = host->hostt->queuecommand(host, cmd);
1670 trace_scsi_dispatch_cmd_error(cmd, rtn);
1671 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
1672 rtn != SCSI_MLQUEUE_TARGET_BUSY)
1673 rtn = SCSI_MLQUEUE_HOST_BUSY;
1675 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1676 "queuecommand : request rejected\n"));
1681 cmd->scsi_done(cmd);
1686 * scsi_done - Invoke completion on finished SCSI command.
1687 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
1688 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
1690 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
1691 * which regains ownership of the SCSI command (de facto) from a LLDD, and
1692 * calls blk_complete_request() for further processing.
1694 * This function is interrupt context safe.
1696 static void scsi_done(struct scsi_cmnd *cmd)
1698 trace_scsi_dispatch_cmd_done(cmd);
1699 blk_complete_request(cmd->request);
1703 * Function: scsi_request_fn()
1705 * Purpose: Main strategy routine for SCSI.
1707 * Arguments: q - Pointer to actual queue.
1711 * Lock status: IO request lock assumed to be held when called.
1713 static void scsi_request_fn(struct request_queue *q)
1714 __releases(q->queue_lock)
1715 __acquires(q->queue_lock)
1717 struct scsi_device *sdev = q->queuedata;
1718 struct Scsi_Host *shost;
1719 struct scsi_cmnd *cmd;
1720 struct request *req;
1723 * To start with, we keep looping until the queue is empty, or until
1724 * the host is no longer able to accept any more requests.
1730 * get next queueable request. We do this early to make sure
1731 * that the request is fully prepared even if we cannot
1734 req = blk_peek_request(q);
1738 if (unlikely(!scsi_device_online(sdev))) {
1739 sdev_printk(KERN_ERR, sdev,
1740 "rejecting I/O to offline device\n");
1741 scsi_kill_request(req, q);
1745 if (!scsi_dev_queue_ready(q, sdev))
1749 * Remove the request from the request list.
1751 if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req)))
1752 blk_start_request(req);
1754 spin_unlock_irq(q->queue_lock);
1756 if (unlikely(cmd == NULL)) {
1757 printk(KERN_CRIT "impossible request in %s.\n"
1758 "please mail a stack trace to "
1759 "linux-scsi@vger.kernel.org\n",
1761 blk_dump_rq_flags(req, "foo");
1766 * We hit this when the driver is using a host wide
1767 * tag map. For device level tag maps the queue_depth check
1768 * in the device ready fn would prevent us from trying
1769 * to allocate a tag. Since the map is a shared host resource
1770 * we add the dev to the starved list so it eventually gets
1771 * a run when a tag is freed.
1773 if (blk_queue_tagged(q) && !(req->rq_flags & RQF_QUEUED)) {
1774 spin_lock_irq(shost->host_lock);
1775 if (list_empty(&sdev->starved_entry))
1776 list_add_tail(&sdev->starved_entry,
1777 &shost->starved_list);
1778 spin_unlock_irq(shost->host_lock);
1782 if (!scsi_target_queue_ready(shost, sdev))
1785 if (!scsi_host_queue_ready(q, shost, sdev))
1786 goto host_not_ready;
1788 if (sdev->simple_tags)
1789 cmd->flags |= SCMD_TAGGED;
1791 cmd->flags &= ~SCMD_TAGGED;
1794 * Finally, initialize any error handling parameters, and set up
1795 * the timers for timeouts.
1797 scsi_init_cmd_errh(cmd);
1800 * Dispatch the command to the low-level driver.
1802 cmd->scsi_done = scsi_done;
1803 rtn = scsi_dispatch_cmd(cmd);
1805 scsi_queue_insert(cmd, rtn);
1806 spin_lock_irq(q->queue_lock);
1809 spin_lock_irq(q->queue_lock);
1815 if (scsi_target(sdev)->can_queue > 0)
1816 atomic_dec(&scsi_target(sdev)->target_busy);
1819 * lock q, handle tag, requeue req, and decrement device_busy. We
1820 * must return with queue_lock held.
1822 * Decrementing device_busy without checking it is OK, as all such
1823 * cases (host limits or settings) should run the queue at some
1826 spin_lock_irq(q->queue_lock);
1827 blk_requeue_request(q, req);
1828 atomic_dec(&sdev->device_busy);
1830 if (!atomic_read(&sdev->device_busy) && !scsi_device_blocked(sdev))
1831 blk_delay_queue(q, SCSI_QUEUE_DELAY);
1834 static inline int prep_to_mq(int ret)
1838 return BLK_MQ_RQ_QUEUE_OK;
1840 return BLK_MQ_RQ_QUEUE_BUSY;
1842 return BLK_MQ_RQ_QUEUE_ERROR;
1846 static int scsi_mq_prep_fn(struct request *req)
1848 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1849 struct scsi_device *sdev = req->q->queuedata;
1850 struct Scsi_Host *shost = sdev->host;
1851 unsigned char *sense_buf = cmd->sense_buffer;
1852 unsigned int unchecked_isa_dma = cmd->flags & SCMD_UNCHECKED_ISA_DMA;
1853 struct scatterlist *sg;
1855 /* zero out the cmd, except for the embedded scsi_request */
1856 memset((char *)cmd + sizeof(cmd->req), 0,
1857 sizeof(*cmd) - sizeof(cmd->req) + shost->hostt->cmd_size);
1863 cmd->sense_buffer = sense_buf;
1864 cmd->flags = unchecked_isa_dma;
1866 cmd->tag = req->tag;
1868 cmd->prot_op = SCSI_PROT_NORMAL;
1870 INIT_LIST_HEAD(&cmd->list);
1871 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
1872 cmd->jiffies_at_alloc = jiffies;
1874 if (shost->use_cmd_list) {
1875 spin_lock_irq(&sdev->list_lock);
1876 list_add_tail(&cmd->list, &sdev->cmd_list);
1877 spin_unlock_irq(&sdev->list_lock);
1880 sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
1881 cmd->sdb.table.sgl = sg;
1883 if (scsi_host_get_prot(shost)) {
1884 cmd->prot_sdb = (void *)sg +
1886 shost->sg_tablesize, SG_CHUNK_SIZE) *
1887 sizeof(struct scatterlist);
1888 memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer));
1890 cmd->prot_sdb->table.sgl =
1891 (struct scatterlist *)(cmd->prot_sdb + 1);
1894 if (blk_bidi_rq(req)) {
1895 struct request *next_rq = req->next_rq;
1896 struct scsi_data_buffer *bidi_sdb = blk_mq_rq_to_pdu(next_rq);
1898 memset(bidi_sdb, 0, sizeof(struct scsi_data_buffer));
1899 bidi_sdb->table.sgl =
1900 (struct scatterlist *)(bidi_sdb + 1);
1902 next_rq->special = bidi_sdb;
1905 blk_mq_start_request(req);
1907 return scsi_setup_cmnd(sdev, req);
1910 static void scsi_mq_done(struct scsi_cmnd *cmd)
1912 trace_scsi_dispatch_cmd_done(cmd);
1913 blk_mq_complete_request(cmd->request);
1916 static int scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
1917 const struct blk_mq_queue_data *bd)
1919 struct request *req = bd->rq;
1920 struct request_queue *q = req->q;
1921 struct scsi_device *sdev = q->queuedata;
1922 struct Scsi_Host *shost = sdev->host;
1923 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1927 ret = prep_to_mq(scsi_prep_state_check(sdev, req));
1928 if (ret != BLK_MQ_RQ_QUEUE_OK)
1931 ret = BLK_MQ_RQ_QUEUE_BUSY;
1932 if (!get_device(&sdev->sdev_gendev))
1935 if (!scsi_dev_queue_ready(q, sdev))
1936 goto out_put_device;
1937 if (!scsi_target_queue_ready(shost, sdev))
1938 goto out_dec_device_busy;
1939 if (!scsi_host_queue_ready(q, shost, sdev))
1940 goto out_dec_target_busy;
1942 if (!(req->rq_flags & RQF_DONTPREP)) {
1943 ret = prep_to_mq(scsi_mq_prep_fn(req));
1944 if (ret != BLK_MQ_RQ_QUEUE_OK)
1945 goto out_dec_host_busy;
1946 req->rq_flags |= RQF_DONTPREP;
1948 blk_mq_start_request(req);
1951 if (sdev->simple_tags)
1952 cmd->flags |= SCMD_TAGGED;
1954 cmd->flags &= ~SCMD_TAGGED;
1956 scsi_init_cmd_errh(cmd);
1957 cmd->scsi_done = scsi_mq_done;
1959 reason = scsi_dispatch_cmd(cmd);
1961 scsi_set_blocked(cmd, reason);
1962 ret = BLK_MQ_RQ_QUEUE_BUSY;
1963 goto out_dec_host_busy;
1966 return BLK_MQ_RQ_QUEUE_OK;
1969 atomic_dec(&shost->host_busy);
1970 out_dec_target_busy:
1971 if (scsi_target(sdev)->can_queue > 0)
1972 atomic_dec(&scsi_target(sdev)->target_busy);
1973 out_dec_device_busy:
1974 atomic_dec(&sdev->device_busy);
1976 put_device(&sdev->sdev_gendev);
1979 case BLK_MQ_RQ_QUEUE_BUSY:
1980 if (atomic_read(&sdev->device_busy) == 0 &&
1981 !scsi_device_blocked(sdev))
1982 blk_mq_delay_run_hw_queue(hctx, SCSI_QUEUE_DELAY);
1984 case BLK_MQ_RQ_QUEUE_ERROR:
1986 * Make sure to release all allocated ressources when
1987 * we hit an error, as we will never see this command
1990 if (req->rq_flags & RQF_DONTPREP)
1991 scsi_mq_uninit_cmd(cmd);
1999 static enum blk_eh_timer_return scsi_timeout(struct request *req,
2003 return BLK_EH_RESET_TIMER;
2004 return scsi_times_out(req);
2007 static int scsi_init_request(struct blk_mq_tag_set *set, struct request *rq,
2008 unsigned int hctx_idx, unsigned int numa_node)
2010 struct Scsi_Host *shost = set->driver_data;
2011 const bool unchecked_isa_dma = shost->unchecked_isa_dma;
2012 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
2014 if (unchecked_isa_dma)
2015 cmd->flags |= SCMD_UNCHECKED_ISA_DMA;
2016 cmd->sense_buffer = scsi_alloc_sense_buffer(unchecked_isa_dma,
2017 GFP_KERNEL, numa_node);
2018 if (!cmd->sense_buffer)
2020 cmd->req.sense = cmd->sense_buffer;
2024 static void scsi_exit_request(struct blk_mq_tag_set *set, struct request *rq,
2025 unsigned int hctx_idx)
2027 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
2029 scsi_free_sense_buffer(cmd->flags & SCMD_UNCHECKED_ISA_DMA,
2033 static int scsi_map_queues(struct blk_mq_tag_set *set)
2035 struct Scsi_Host *shost = container_of(set, struct Scsi_Host, tag_set);
2037 if (shost->hostt->map_queues)
2038 return shost->hostt->map_queues(shost);
2039 return blk_mq_map_queues(set);
2042 static u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost)
2044 struct device *host_dev;
2045 u64 bounce_limit = 0xffffffff;
2047 if (shost->unchecked_isa_dma)
2048 return BLK_BOUNCE_ISA;
2050 * Platforms with virtual-DMA translation
2051 * hardware have no practical limit.
2053 if (!PCI_DMA_BUS_IS_PHYS)
2054 return BLK_BOUNCE_ANY;
2056 host_dev = scsi_get_device(shost);
2057 if (host_dev && host_dev->dma_mask)
2058 bounce_limit = (u64)dma_max_pfn(host_dev) << PAGE_SHIFT;
2060 return bounce_limit;
2063 void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
2065 struct device *dev = shost->dma_dev;
2068 * this limit is imposed by hardware restrictions
2070 blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
2073 if (scsi_host_prot_dma(shost)) {
2074 shost->sg_prot_tablesize =
2075 min_not_zero(shost->sg_prot_tablesize,
2076 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
2077 BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
2078 blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
2081 blk_queue_max_hw_sectors(q, shost->max_sectors);
2082 blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost));
2083 blk_queue_segment_boundary(q, shost->dma_boundary);
2084 dma_set_seg_boundary(dev, shost->dma_boundary);
2086 blk_queue_max_segment_size(q, dma_get_max_seg_size(dev));
2088 if (!shost->use_clustering)
2089 q->limits.cluster = 0;
2092 * set a reasonable default alignment on word boundaries: the
2093 * host and device may alter it using
2094 * blk_queue_update_dma_alignment() later.
2096 blk_queue_dma_alignment(q, 0x03);
2098 EXPORT_SYMBOL_GPL(__scsi_init_queue);
2100 static int scsi_init_rq(struct request_queue *q, struct request *rq, gfp_t gfp)
2102 struct Scsi_Host *shost = q->rq_alloc_data;
2103 const bool unchecked_isa_dma = shost->unchecked_isa_dma;
2104 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
2106 memset(cmd, 0, sizeof(*cmd));
2108 if (unchecked_isa_dma)
2109 cmd->flags |= SCMD_UNCHECKED_ISA_DMA;
2110 cmd->sense_buffer = scsi_alloc_sense_buffer(unchecked_isa_dma, gfp,
2112 if (!cmd->sense_buffer)
2114 cmd->req.sense = cmd->sense_buffer;
2116 if (scsi_host_get_prot(shost) >= SHOST_DIX_TYPE0_PROTECTION) {
2117 cmd->prot_sdb = kmem_cache_zalloc(scsi_sdb_cache, gfp);
2119 goto fail_free_sense;
2125 scsi_free_sense_buffer(unchecked_isa_dma, cmd->sense_buffer);
2130 static void scsi_exit_rq(struct request_queue *q, struct request *rq)
2132 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
2135 kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb);
2136 scsi_free_sense_buffer(cmd->flags & SCMD_UNCHECKED_ISA_DMA,
2140 struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
2142 struct Scsi_Host *shost = sdev->host;
2143 struct request_queue *q;
2145 q = blk_alloc_queue_node(GFP_KERNEL, NUMA_NO_NODE);
2148 q->cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
2149 q->rq_alloc_data = shost;
2150 q->request_fn = scsi_request_fn;
2151 q->init_rq_fn = scsi_init_rq;
2152 q->exit_rq_fn = scsi_exit_rq;
2154 if (blk_init_allocated_queue(q) < 0) {
2155 blk_cleanup_queue(q);
2159 __scsi_init_queue(shost, q);
2160 blk_queue_prep_rq(q, scsi_prep_fn);
2161 blk_queue_unprep_rq(q, scsi_unprep_fn);
2162 blk_queue_softirq_done(q, scsi_softirq_done);
2163 blk_queue_rq_timed_out(q, scsi_times_out);
2164 blk_queue_lld_busy(q, scsi_lld_busy);
2168 static const struct blk_mq_ops scsi_mq_ops = {
2169 .queue_rq = scsi_queue_rq,
2170 .complete = scsi_softirq_done,
2171 .timeout = scsi_timeout,
2172 #ifdef CONFIG_BLK_DEBUG_FS
2173 .show_rq = scsi_show_rq,
2175 .init_request = scsi_init_request,
2176 .exit_request = scsi_exit_request,
2177 .map_queues = scsi_map_queues,
2180 struct request_queue *scsi_mq_alloc_queue(struct scsi_device *sdev)
2182 sdev->request_queue = blk_mq_init_queue(&sdev->host->tag_set);
2183 if (IS_ERR(sdev->request_queue))
2186 sdev->request_queue->queuedata = sdev;
2187 __scsi_init_queue(sdev->host, sdev->request_queue);
2188 return sdev->request_queue;
2191 int scsi_mq_setup_tags(struct Scsi_Host *shost)
2193 unsigned int cmd_size, sgl_size, tbl_size;
2195 tbl_size = shost->sg_tablesize;
2196 if (tbl_size > SG_CHUNK_SIZE)
2197 tbl_size = SG_CHUNK_SIZE;
2198 sgl_size = tbl_size * sizeof(struct scatterlist);
2199 cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size;
2200 if (scsi_host_get_prot(shost))
2201 cmd_size += sizeof(struct scsi_data_buffer) + sgl_size;
2203 memset(&shost->tag_set, 0, sizeof(shost->tag_set));
2204 shost->tag_set.ops = &scsi_mq_ops;
2205 shost->tag_set.nr_hw_queues = shost->nr_hw_queues ? : 1;
2206 shost->tag_set.queue_depth = shost->can_queue;
2207 shost->tag_set.cmd_size = cmd_size;
2208 shost->tag_set.numa_node = NUMA_NO_NODE;
2209 shost->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
2210 shost->tag_set.flags |=
2211 BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
2212 shost->tag_set.driver_data = shost;
2214 return blk_mq_alloc_tag_set(&shost->tag_set);
2217 void scsi_mq_destroy_tags(struct Scsi_Host *shost)
2219 blk_mq_free_tag_set(&shost->tag_set);
2223 * scsi_device_from_queue - return sdev associated with a request_queue
2224 * @q: The request queue to return the sdev from
2226 * Return the sdev associated with a request queue or NULL if the
2227 * request_queue does not reference a SCSI device.
2229 struct scsi_device *scsi_device_from_queue(struct request_queue *q)
2231 struct scsi_device *sdev = NULL;
2234 if (q->mq_ops == &scsi_mq_ops)
2235 sdev = q->queuedata;
2236 } else if (q->request_fn == scsi_request_fn)
2237 sdev = q->queuedata;
2238 if (!sdev || !get_device(&sdev->sdev_gendev))
2243 EXPORT_SYMBOL_GPL(scsi_device_from_queue);
2246 * Function: scsi_block_requests()
2248 * Purpose: Utility function used by low-level drivers to prevent further
2249 * commands from being queued to the device.
2251 * Arguments: shost - Host in question
2255 * Lock status: No locks are assumed held.
2257 * Notes: There is no timer nor any other means by which the requests
2258 * get unblocked other than the low-level driver calling
2259 * scsi_unblock_requests().
2261 void scsi_block_requests(struct Scsi_Host *shost)
2263 shost->host_self_blocked = 1;
2265 EXPORT_SYMBOL(scsi_block_requests);
2268 * Function: scsi_unblock_requests()
2270 * Purpose: Utility function used by low-level drivers to allow further
2271 * commands from being queued to the device.
2273 * Arguments: shost - Host in question
2277 * Lock status: No locks are assumed held.
2279 * Notes: There is no timer nor any other means by which the requests
2280 * get unblocked other than the low-level driver calling
2281 * scsi_unblock_requests().
2283 * This is done as an API function so that changes to the
2284 * internals of the scsi mid-layer won't require wholesale
2285 * changes to drivers that use this feature.
2287 void scsi_unblock_requests(struct Scsi_Host *shost)
2289 shost->host_self_blocked = 0;
2290 scsi_run_host_queues(shost);
2292 EXPORT_SYMBOL(scsi_unblock_requests);
2294 int __init scsi_init_queue(void)
2296 scsi_sdb_cache = kmem_cache_create("scsi_data_buffer",
2297 sizeof(struct scsi_data_buffer),
2299 if (!scsi_sdb_cache) {
2300 printk(KERN_ERR "SCSI: can't init scsi sdb cache\n");
2307 void scsi_exit_queue(void)
2309 kmem_cache_destroy(scsi_sense_cache);
2310 kmem_cache_destroy(scsi_sense_isadma_cache);
2311 kmem_cache_destroy(scsi_sdb_cache);
2315 * scsi_mode_select - issue a mode select
2316 * @sdev: SCSI device to be queried
2317 * @pf: Page format bit (1 == standard, 0 == vendor specific)
2318 * @sp: Save page bit (0 == don't save, 1 == save)
2319 * @modepage: mode page being requested
2320 * @buffer: request buffer (may not be smaller than eight bytes)
2321 * @len: length of request buffer.
2322 * @timeout: command timeout
2323 * @retries: number of retries before failing
2324 * @data: returns a structure abstracting the mode header data
2325 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2326 * must be SCSI_SENSE_BUFFERSIZE big.
2328 * Returns zero if successful; negative error number or scsi
2333 scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
2334 unsigned char *buffer, int len, int timeout, int retries,
2335 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2337 unsigned char cmd[10];
2338 unsigned char *real_buffer;
2341 memset(cmd, 0, sizeof(cmd));
2342 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
2344 if (sdev->use_10_for_ms) {
2347 real_buffer = kmalloc(8 + len, GFP_KERNEL);
2350 memcpy(real_buffer + 8, buffer, len);
2354 real_buffer[2] = data->medium_type;
2355 real_buffer[3] = data->device_specific;
2356 real_buffer[4] = data->longlba ? 0x01 : 0;
2358 real_buffer[6] = data->block_descriptor_length >> 8;
2359 real_buffer[7] = data->block_descriptor_length;
2361 cmd[0] = MODE_SELECT_10;
2365 if (len > 255 || data->block_descriptor_length > 255 ||
2369 real_buffer = kmalloc(4 + len, GFP_KERNEL);
2372 memcpy(real_buffer + 4, buffer, len);
2375 real_buffer[1] = data->medium_type;
2376 real_buffer[2] = data->device_specific;
2377 real_buffer[3] = data->block_descriptor_length;
2380 cmd[0] = MODE_SELECT;
2384 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
2385 sshdr, timeout, retries, NULL);
2389 EXPORT_SYMBOL_GPL(scsi_mode_select);
2392 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
2393 * @sdev: SCSI device to be queried
2394 * @dbd: set if mode sense will allow block descriptors to be returned
2395 * @modepage: mode page being requested
2396 * @buffer: request buffer (may not be smaller than eight bytes)
2397 * @len: length of request buffer.
2398 * @timeout: command timeout
2399 * @retries: number of retries before failing
2400 * @data: returns a structure abstracting the mode header data
2401 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2402 * must be SCSI_SENSE_BUFFERSIZE big.
2404 * Returns zero if unsuccessful, or the header offset (either 4
2405 * or 8 depending on whether a six or ten byte command was
2406 * issued) if successful.
2409 scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
2410 unsigned char *buffer, int len, int timeout, int retries,
2411 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2413 unsigned char cmd[12];
2416 int result, retry_count = retries;
2417 struct scsi_sense_hdr my_sshdr;
2419 memset(data, 0, sizeof(*data));
2420 memset(&cmd[0], 0, 12);
2421 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
2424 /* caller might not be interested in sense, but we need it */
2429 use_10_for_ms = sdev->use_10_for_ms;
2431 if (use_10_for_ms) {
2435 cmd[0] = MODE_SENSE_10;
2442 cmd[0] = MODE_SENSE;
2447 memset(buffer, 0, len);
2449 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
2450 sshdr, timeout, retries, NULL);
2452 /* This code looks awful: what it's doing is making sure an
2453 * ILLEGAL REQUEST sense return identifies the actual command
2454 * byte as the problem. MODE_SENSE commands can return
2455 * ILLEGAL REQUEST if the code page isn't supported */
2457 if (use_10_for_ms && !scsi_status_is_good(result) &&
2458 (driver_byte(result) & DRIVER_SENSE)) {
2459 if (scsi_sense_valid(sshdr)) {
2460 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
2461 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
2463 * Invalid command operation code
2465 sdev->use_10_for_ms = 0;
2471 if(scsi_status_is_good(result)) {
2472 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
2473 (modepage == 6 || modepage == 8))) {
2474 /* Initio breakage? */
2477 data->medium_type = 0;
2478 data->device_specific = 0;
2480 data->block_descriptor_length = 0;
2481 } else if(use_10_for_ms) {
2482 data->length = buffer[0]*256 + buffer[1] + 2;
2483 data->medium_type = buffer[2];
2484 data->device_specific = buffer[3];
2485 data->longlba = buffer[4] & 0x01;
2486 data->block_descriptor_length = buffer[6]*256
2489 data->length = buffer[0] + 1;
2490 data->medium_type = buffer[1];
2491 data->device_specific = buffer[2];
2492 data->block_descriptor_length = buffer[3];
2494 data->header_length = header_length;
2495 } else if ((status_byte(result) == CHECK_CONDITION) &&
2496 scsi_sense_valid(sshdr) &&
2497 sshdr->sense_key == UNIT_ATTENTION && retry_count) {
2504 EXPORT_SYMBOL(scsi_mode_sense);
2507 * scsi_test_unit_ready - test if unit is ready
2508 * @sdev: scsi device to change the state of.
2509 * @timeout: command timeout
2510 * @retries: number of retries before failing
2511 * @sshdr: outpout pointer for decoded sense information.
2513 * Returns zero if unsuccessful or an error if TUR failed. For
2514 * removable media, UNIT_ATTENTION sets ->changed flag.
2517 scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2518 struct scsi_sense_hdr *sshdr)
2521 TEST_UNIT_READY, 0, 0, 0, 0, 0,
2525 /* try to eat the UNIT_ATTENTION if there are enough retries */
2527 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
2528 timeout, retries, NULL);
2529 if (sdev->removable && scsi_sense_valid(sshdr) &&
2530 sshdr->sense_key == UNIT_ATTENTION)
2532 } while (scsi_sense_valid(sshdr) &&
2533 sshdr->sense_key == UNIT_ATTENTION && --retries);
2537 EXPORT_SYMBOL(scsi_test_unit_ready);
2540 * scsi_device_set_state - Take the given device through the device state model.
2541 * @sdev: scsi device to change the state of.
2542 * @state: state to change to.
2544 * Returns zero if unsuccessful or an error if the requested
2545 * transition is illegal.
2548 scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2550 enum scsi_device_state oldstate = sdev->sdev_state;
2552 if (state == oldstate)
2558 case SDEV_CREATED_BLOCK:
2569 case SDEV_TRANSPORT_OFFLINE:
2582 case SDEV_TRANSPORT_OFFLINE:
2590 case SDEV_TRANSPORT_OFFLINE:
2605 case SDEV_CREATED_BLOCK:
2612 case SDEV_CREATED_BLOCK:
2627 case SDEV_TRANSPORT_OFFLINE:
2640 case SDEV_TRANSPORT_OFFLINE:
2642 case SDEV_CREATED_BLOCK:
2650 sdev->sdev_state = state;
2654 SCSI_LOG_ERROR_RECOVERY(1,
2655 sdev_printk(KERN_ERR, sdev,
2656 "Illegal state transition %s->%s",
2657 scsi_device_state_name(oldstate),
2658 scsi_device_state_name(state))
2662 EXPORT_SYMBOL(scsi_device_set_state);
2665 * sdev_evt_emit - emit a single SCSI device uevent
2666 * @sdev: associated SCSI device
2667 * @evt: event to emit
2669 * Send a single uevent (scsi_event) to the associated scsi_device.
2671 static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2676 switch (evt->evt_type) {
2677 case SDEV_EVT_MEDIA_CHANGE:
2678 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2680 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2681 scsi_rescan_device(&sdev->sdev_gendev);
2682 envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2684 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2685 envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2687 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2688 envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2690 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2691 envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2693 case SDEV_EVT_LUN_CHANGE_REPORTED:
2694 envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2696 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2697 envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
2706 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2710 * sdev_evt_thread - send a uevent for each scsi event
2711 * @work: work struct for scsi_device
2713 * Dispatch queued events to their associated scsi_device kobjects
2716 void scsi_evt_thread(struct work_struct *work)
2718 struct scsi_device *sdev;
2719 enum scsi_device_event evt_type;
2720 LIST_HEAD(event_list);
2722 sdev = container_of(work, struct scsi_device, event_work);
2724 for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
2725 if (test_and_clear_bit(evt_type, sdev->pending_events))
2726 sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
2729 struct scsi_event *evt;
2730 struct list_head *this, *tmp;
2731 unsigned long flags;
2733 spin_lock_irqsave(&sdev->list_lock, flags);
2734 list_splice_init(&sdev->event_list, &event_list);
2735 spin_unlock_irqrestore(&sdev->list_lock, flags);
2737 if (list_empty(&event_list))
2740 list_for_each_safe(this, tmp, &event_list) {
2741 evt = list_entry(this, struct scsi_event, node);
2742 list_del(&evt->node);
2743 scsi_evt_emit(sdev, evt);
2750 * sdev_evt_send - send asserted event to uevent thread
2751 * @sdev: scsi_device event occurred on
2752 * @evt: event to send
2754 * Assert scsi device event asynchronously.
2756 void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2758 unsigned long flags;
2761 /* FIXME: currently this check eliminates all media change events
2762 * for polled devices. Need to update to discriminate between AN
2763 * and polled events */
2764 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2770 spin_lock_irqsave(&sdev->list_lock, flags);
2771 list_add_tail(&evt->node, &sdev->event_list);
2772 schedule_work(&sdev->event_work);
2773 spin_unlock_irqrestore(&sdev->list_lock, flags);
2775 EXPORT_SYMBOL_GPL(sdev_evt_send);
2778 * sdev_evt_alloc - allocate a new scsi event
2779 * @evt_type: type of event to allocate
2780 * @gfpflags: GFP flags for allocation
2782 * Allocates and returns a new scsi_event.
2784 struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2787 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2791 evt->evt_type = evt_type;
2792 INIT_LIST_HEAD(&evt->node);
2794 /* evt_type-specific initialization, if any */
2796 case SDEV_EVT_MEDIA_CHANGE:
2797 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2798 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2799 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2800 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2801 case SDEV_EVT_LUN_CHANGE_REPORTED:
2802 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2810 EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2813 * sdev_evt_send_simple - send asserted event to uevent thread
2814 * @sdev: scsi_device event occurred on
2815 * @evt_type: type of event to send
2816 * @gfpflags: GFP flags for allocation
2818 * Assert scsi device event asynchronously, given an event type.
2820 void sdev_evt_send_simple(struct scsi_device *sdev,
2821 enum scsi_device_event evt_type, gfp_t gfpflags)
2823 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2825 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2830 sdev_evt_send(sdev, evt);
2832 EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2835 * scsi_request_fn_active() - number of kernel threads inside scsi_request_fn()
2836 * @sdev: SCSI device to count the number of scsi_request_fn() callers for.
2838 static int scsi_request_fn_active(struct scsi_device *sdev)
2840 struct request_queue *q = sdev->request_queue;
2841 int request_fn_active;
2843 WARN_ON_ONCE(sdev->host->use_blk_mq);
2845 spin_lock_irq(q->queue_lock);
2846 request_fn_active = q->request_fn_active;
2847 spin_unlock_irq(q->queue_lock);
2849 return request_fn_active;
2853 * scsi_wait_for_queuecommand() - wait for ongoing queuecommand() calls
2854 * @sdev: SCSI device pointer.
2856 * Wait until the ongoing shost->hostt->queuecommand() calls that are
2857 * invoked from scsi_request_fn() have finished.
2859 static void scsi_wait_for_queuecommand(struct scsi_device *sdev)
2861 WARN_ON_ONCE(sdev->host->use_blk_mq);
2863 while (scsi_request_fn_active(sdev))
2868 * scsi_device_quiesce - Block user issued commands.
2869 * @sdev: scsi device to quiesce.
2871 * This works by trying to transition to the SDEV_QUIESCE state
2872 * (which must be a legal transition). When the device is in this
2873 * state, only special requests will be accepted, all others will
2874 * be deferred. Since special requests may also be requeued requests,
2875 * a successful return doesn't guarantee the device will be
2876 * totally quiescent.
2878 * Must be called with user context, may sleep.
2880 * Returns zero if unsuccessful or an error if not.
2883 scsi_device_quiesce(struct scsi_device *sdev)
2887 mutex_lock(&sdev->state_mutex);
2888 err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2889 mutex_unlock(&sdev->state_mutex);
2894 scsi_run_queue(sdev->request_queue);
2895 while (atomic_read(&sdev->device_busy)) {
2896 msleep_interruptible(200);
2897 scsi_run_queue(sdev->request_queue);
2901 EXPORT_SYMBOL(scsi_device_quiesce);
2904 * scsi_device_resume - Restart user issued commands to a quiesced device.
2905 * @sdev: scsi device to resume.
2907 * Moves the device from quiesced back to running and restarts the
2910 * Must be called with user context, may sleep.
2912 void scsi_device_resume(struct scsi_device *sdev)
2914 /* check if the device state was mutated prior to resume, and if
2915 * so assume the state is being managed elsewhere (for example
2916 * device deleted during suspend)
2918 mutex_lock(&sdev->state_mutex);
2919 if (sdev->sdev_state == SDEV_QUIESCE &&
2920 scsi_device_set_state(sdev, SDEV_RUNNING) == 0)
2921 scsi_run_queue(sdev->request_queue);
2922 mutex_unlock(&sdev->state_mutex);
2924 EXPORT_SYMBOL(scsi_device_resume);
2927 device_quiesce_fn(struct scsi_device *sdev, void *data)
2929 scsi_device_quiesce(sdev);
2933 scsi_target_quiesce(struct scsi_target *starget)
2935 starget_for_each_device(starget, NULL, device_quiesce_fn);
2937 EXPORT_SYMBOL(scsi_target_quiesce);
2940 device_resume_fn(struct scsi_device *sdev, void *data)
2942 scsi_device_resume(sdev);
2946 scsi_target_resume(struct scsi_target *starget)
2948 starget_for_each_device(starget, NULL, device_resume_fn);
2950 EXPORT_SYMBOL(scsi_target_resume);
2953 * scsi_internal_device_block_nowait - try to transition to the SDEV_BLOCK state
2954 * @sdev: device to block
2956 * Pause SCSI command processing on the specified device. Does not sleep.
2958 * Returns zero if successful or a negative error code upon failure.
2961 * This routine transitions the device to the SDEV_BLOCK state (which must be
2962 * a legal transition). When the device is in this state, command processing
2963 * is paused until the device leaves the SDEV_BLOCK state. See also
2964 * scsi_internal_device_unblock_nowait().
2966 int scsi_internal_device_block_nowait(struct scsi_device *sdev)
2968 struct request_queue *q = sdev->request_queue;
2969 unsigned long flags;
2972 err = scsi_device_set_state(sdev, SDEV_BLOCK);
2974 err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2981 * The device has transitioned to SDEV_BLOCK. Stop the
2982 * block layer from calling the midlayer with this device's
2986 blk_mq_stop_hw_queues(q);
2988 spin_lock_irqsave(q->queue_lock, flags);
2990 spin_unlock_irqrestore(q->queue_lock, flags);
2995 EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait);
2998 * scsi_internal_device_block - try to transition to the SDEV_BLOCK state
2999 * @sdev: device to block
3001 * Pause SCSI command processing on the specified device and wait until all
3002 * ongoing scsi_request_fn() / scsi_queue_rq() calls have finished. May sleep.
3004 * Returns zero if successful or a negative error code upon failure.
3007 * This routine transitions the device to the SDEV_BLOCK state (which must be
3008 * a legal transition). When the device is in this state, command processing
3009 * is paused until the device leaves the SDEV_BLOCK state. See also
3010 * scsi_internal_device_unblock().
3012 * To do: avoid that scsi_send_eh_cmnd() calls queuecommand() after
3013 * scsi_internal_device_block() has blocked a SCSI device and also
3014 * remove the rport mutex lock and unlock calls from srp_queuecommand().
3016 static int scsi_internal_device_block(struct scsi_device *sdev)
3018 struct request_queue *q = sdev->request_queue;
3021 mutex_lock(&sdev->state_mutex);
3022 err = scsi_internal_device_block_nowait(sdev);
3025 blk_mq_quiesce_queue(q);
3027 scsi_wait_for_queuecommand(sdev);
3029 mutex_unlock(&sdev->state_mutex);
3034 void scsi_start_queue(struct scsi_device *sdev)
3036 struct request_queue *q = sdev->request_queue;
3037 unsigned long flags;
3040 blk_mq_start_stopped_hw_queues(q, false);
3042 spin_lock_irqsave(q->queue_lock, flags);
3044 spin_unlock_irqrestore(q->queue_lock, flags);
3049 * scsi_internal_device_unblock_nowait - resume a device after a block request
3050 * @sdev: device to resume
3051 * @new_state: state to set the device to after unblocking
3053 * Restart the device queue for a previously suspended SCSI device. Does not
3056 * Returns zero if successful or a negative error code upon failure.
3059 * This routine transitions the device to the SDEV_RUNNING state or to one of
3060 * the offline states (which must be a legal transition) allowing the midlayer
3061 * to goose the queue for this device.
3063 int scsi_internal_device_unblock_nowait(struct scsi_device *sdev,
3064 enum scsi_device_state new_state)
3067 * Try to transition the scsi device to SDEV_RUNNING or one of the
3068 * offlined states and goose the device queue if successful.
3070 if ((sdev->sdev_state == SDEV_BLOCK) ||
3071 (sdev->sdev_state == SDEV_TRANSPORT_OFFLINE))
3072 sdev->sdev_state = new_state;
3073 else if (sdev->sdev_state == SDEV_CREATED_BLOCK) {
3074 if (new_state == SDEV_TRANSPORT_OFFLINE ||
3075 new_state == SDEV_OFFLINE)
3076 sdev->sdev_state = new_state;
3078 sdev->sdev_state = SDEV_CREATED;
3079 } else if (sdev->sdev_state != SDEV_CANCEL &&
3080 sdev->sdev_state != SDEV_OFFLINE)
3083 scsi_start_queue(sdev);
3087 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock_nowait);
3090 * scsi_internal_device_unblock - resume a device after a block request
3091 * @sdev: device to resume
3092 * @new_state: state to set the device to after unblocking
3094 * Restart the device queue for a previously suspended SCSI device. May sleep.
3096 * Returns zero if successful or a negative error code upon failure.
3099 * This routine transitions the device to the SDEV_RUNNING state or to one of
3100 * the offline states (which must be a legal transition) allowing the midlayer
3101 * to goose the queue for this device.
3103 static int scsi_internal_device_unblock(struct scsi_device *sdev,
3104 enum scsi_device_state new_state)
3108 mutex_lock(&sdev->state_mutex);
3109 ret = scsi_internal_device_unblock_nowait(sdev, new_state);
3110 mutex_unlock(&sdev->state_mutex);
3116 device_block(struct scsi_device *sdev, void *data)
3118 scsi_internal_device_block(sdev);
3122 target_block(struct device *dev, void *data)
3124 if (scsi_is_target_device(dev))
3125 starget_for_each_device(to_scsi_target(dev), NULL,
3131 scsi_target_block(struct device *dev)
3133 if (scsi_is_target_device(dev))
3134 starget_for_each_device(to_scsi_target(dev), NULL,
3137 device_for_each_child(dev, NULL, target_block);
3139 EXPORT_SYMBOL_GPL(scsi_target_block);
3142 device_unblock(struct scsi_device *sdev, void *data)
3144 scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
3148 target_unblock(struct device *dev, void *data)
3150 if (scsi_is_target_device(dev))
3151 starget_for_each_device(to_scsi_target(dev), data,
3157 scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
3159 if (scsi_is_target_device(dev))
3160 starget_for_each_device(to_scsi_target(dev), &new_state,
3163 device_for_each_child(dev, &new_state, target_unblock);
3165 EXPORT_SYMBOL_GPL(scsi_target_unblock);
3168 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
3169 * @sgl: scatter-gather list
3170 * @sg_count: number of segments in sg
3171 * @offset: offset in bytes into sg, on return offset into the mapped area
3172 * @len: bytes to map, on return number of bytes mapped
3174 * Returns virtual address of the start of the mapped page
3176 void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
3177 size_t *offset, size_t *len)
3180 size_t sg_len = 0, len_complete = 0;
3181 struct scatterlist *sg;
3184 WARN_ON(!irqs_disabled());
3186 for_each_sg(sgl, sg, sg_count, i) {
3187 len_complete = sg_len; /* Complete sg-entries */
3188 sg_len += sg->length;
3189 if (sg_len > *offset)
3193 if (unlikely(i == sg_count)) {
3194 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
3196 __func__, sg_len, *offset, sg_count);
3201 /* Offset starting from the beginning of first page in this sg-entry */
3202 *offset = *offset - len_complete + sg->offset;
3204 /* Assumption: contiguous pages can be accessed as "page + i" */
3205 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
3206 *offset &= ~PAGE_MASK;
3208 /* Bytes in this sg-entry from *offset to the end of the page */
3209 sg_len = PAGE_SIZE - *offset;
3213 return kmap_atomic(page);
3215 EXPORT_SYMBOL(scsi_kmap_atomic_sg);
3218 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
3219 * @virt: virtual address to be unmapped
3221 void scsi_kunmap_atomic_sg(void *virt)
3223 kunmap_atomic(virt);
3225 EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
3227 void sdev_disable_disk_events(struct scsi_device *sdev)
3229 atomic_inc(&sdev->disk_events_disable_depth);
3231 EXPORT_SYMBOL(sdev_disable_disk_events);
3233 void sdev_enable_disk_events(struct scsi_device *sdev)
3235 if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0))
3237 atomic_dec(&sdev->disk_events_disable_depth);
3239 EXPORT_SYMBOL(sdev_enable_disk_events);
3242 * scsi_vpd_lun_id - return a unique device identification
3243 * @sdev: SCSI device
3244 * @id: buffer for the identification
3245 * @id_len: length of the buffer
3247 * Copies a unique device identification into @id based
3248 * on the information in the VPD page 0x83 of the device.
3249 * The string will be formatted as a SCSI name string.
3251 * Returns the length of the identification or error on failure.
3252 * If the identifier is longer than the supplied buffer the actual
3253 * identifier length is returned and the buffer is not zero-padded.
3255 int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len)
3257 u8 cur_id_type = 0xff;
3259 unsigned char *d, *cur_id_str;
3260 unsigned char __rcu *vpd_pg83;
3261 int id_size = -EINVAL;
3264 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3271 * Look for the correct descriptor.
3272 * Order of preference for lun descriptor:
3273 * - SCSI name string
3274 * - NAA IEEE Registered Extended
3275 * - EUI-64 based 16-byte
3276 * - EUI-64 based 12-byte
3277 * - NAA IEEE Registered
3278 * - NAA IEEE Extended
3280 * as longer descriptors reduce the likelyhood
3281 * of identification clashes.
3284 /* The id string must be at least 20 bytes + terminating NULL byte */
3290 memset(id, 0, id_len);
3292 while (d < vpd_pg83 + sdev->vpd_pg83_len) {
3293 /* Skip designators not referring to the LUN */
3294 if ((d[1] & 0x30) != 0x00)
3297 switch (d[1] & 0xf) {
3300 if (cur_id_size > d[3])
3302 /* Prefer anything */
3303 if (cur_id_type > 0x01 && cur_id_type != 0xff)
3306 if (cur_id_size + 4 > id_len)
3307 cur_id_size = id_len - 4;
3309 cur_id_type = d[1] & 0xf;
3310 id_size = snprintf(id, id_len, "t10.%*pE",
3311 cur_id_size, cur_id_str);
3315 if (cur_id_size > d[3])
3317 /* Prefer NAA IEEE Registered Extended */
3318 if (cur_id_type == 0x3 &&
3319 cur_id_size == d[3])
3323 cur_id_type = d[1] & 0xf;
3324 switch (cur_id_size) {
3326 id_size = snprintf(id, id_len,
3331 id_size = snprintf(id, id_len,
3336 id_size = snprintf(id, id_len,
3347 if (cur_id_size > d[3])
3351 cur_id_type = d[1] & 0xf;
3352 switch (cur_id_size) {
3354 id_size = snprintf(id, id_len,
3359 id_size = snprintf(id, id_len,
3369 /* SCSI name string */
3370 if (cur_id_size + 4 > d[3])
3372 /* Prefer others for truncated descriptor */
3373 if (cur_id_size && d[3] > id_len)
3375 cur_id_size = id_size = d[3];
3377 cur_id_type = d[1] & 0xf;
3378 if (cur_id_size >= id_len)
3379 cur_id_size = id_len - 1;
3380 memcpy(id, cur_id_str, cur_id_size);
3381 /* Decrease priority for truncated descriptor */
3382 if (cur_id_size != id_size)
3395 EXPORT_SYMBOL(scsi_vpd_lun_id);
3398 * scsi_vpd_tpg_id - return a target port group identifier
3399 * @sdev: SCSI device
3401 * Returns the Target Port Group identifier from the information
3402 * froom VPD page 0x83 of the device.
3404 * Returns the identifier or error on failure.
3406 int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id)
3409 unsigned char __rcu *vpd_pg83;
3410 int group_id = -EAGAIN, rel_port = -1;
3413 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3419 d = sdev->vpd_pg83 + 4;
3420 while (d < sdev->vpd_pg83 + sdev->vpd_pg83_len) {
3421 switch (d[1] & 0xf) {
3423 /* Relative target port */
3424 rel_port = get_unaligned_be16(&d[6]);
3427 /* Target port group */
3428 group_id = get_unaligned_be16(&d[6]);
3437 if (group_id >= 0 && rel_id && rel_port != -1)
3442 EXPORT_SYMBOL(scsi_vpd_tpg_id);