2 * scsi_lib.c Copyright (C) 1999 Eric Youngdale
4 * SCSI queueing library.
5 * Initial versions: Eric Youngdale (eric@andante.org).
6 * Based upon conversations with large numbers
7 * of people at Linux Expo.
10 #include <linux/bio.h>
11 #include <linux/bitops.h>
12 #include <linux/blkdev.h>
13 #include <linux/completion.h>
14 #include <linux/kernel.h>
15 #include <linux/export.h>
16 #include <linux/mempool.h>
17 #include <linux/slab.h>
18 #include <linux/init.h>
19 #include <linux/pci.h>
20 #include <linux/delay.h>
21 #include <linux/hardirq.h>
22 #include <linux/scatterlist.h>
24 #include <scsi/scsi.h>
25 #include <scsi/scsi_cmnd.h>
26 #include <scsi/scsi_dbg.h>
27 #include <scsi/scsi_device.h>
28 #include <scsi/scsi_driver.h>
29 #include <scsi/scsi_eh.h>
30 #include <scsi/scsi_host.h>
32 #include "scsi_priv.h"
33 #include "scsi_logging.h"
36 #define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools)
37 #define SG_MEMPOOL_SIZE 2
39 struct scsi_host_sg_pool {
42 struct kmem_cache *slab;
46 #define SP(x) { x, "sgpool-" __stringify(x) }
47 #if (SCSI_MAX_SG_SEGMENTS < 32)
48 #error SCSI_MAX_SG_SEGMENTS is too small (must be 32 or greater)
50 static struct scsi_host_sg_pool scsi_sg_pools[] = {
53 #if (SCSI_MAX_SG_SEGMENTS > 32)
55 #if (SCSI_MAX_SG_SEGMENTS > 64)
57 #if (SCSI_MAX_SG_SEGMENTS > 128)
59 #if (SCSI_MAX_SG_SEGMENTS > 256)
60 #error SCSI_MAX_SG_SEGMENTS is too large (256 MAX)
65 SP(SCSI_MAX_SG_SEGMENTS)
69 struct kmem_cache *scsi_sdb_cache;
72 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
73 * not change behaviour from the previous unplug mechanism, experimentation
74 * may prove this needs changing.
76 #define SCSI_QUEUE_DELAY 3
79 * Function: scsi_unprep_request()
81 * Purpose: Remove all preparation done for a request, including its
82 * associated scsi_cmnd, so that it can be requeued.
84 * Arguments: req - request to unprepare
86 * Lock status: Assumed that no locks are held upon entry.
90 static void scsi_unprep_request(struct request *req)
92 struct scsi_cmnd *cmd = req->special;
94 blk_unprep_request(req);
97 scsi_put_command(cmd);
98 put_device(&cmd->device->sdev_gendev);
102 * __scsi_queue_insert - private queue insertion
103 * @cmd: The SCSI command being requeued
104 * @reason: The reason for the requeue
105 * @unbusy: Whether the queue should be unbusied
107 * This is a private queue insertion. The public interface
108 * scsi_queue_insert() always assumes the queue should be unbusied
109 * because it's always called before the completion. This function is
110 * for a requeue after completion, which should only occur in this
113 static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy)
115 struct Scsi_Host *host = cmd->device->host;
116 struct scsi_device *device = cmd->device;
117 struct scsi_target *starget = scsi_target(device);
118 struct request_queue *q = device->request_queue;
122 printk("Inserting command %p into mlqueue\n", cmd));
125 * Set the appropriate busy bit for the device/host.
127 * If the host/device isn't busy, assume that something actually
128 * completed, and that we should be able to queue a command now.
130 * Note that the prior mid-layer assumption that any host could
131 * always queue at least one command is now broken. The mid-layer
132 * will implement a user specifiable stall (see
133 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
134 * if a command is requeued with no other commands outstanding
135 * either for the device or for the host.
138 case SCSI_MLQUEUE_HOST_BUSY:
139 host->host_blocked = host->max_host_blocked;
141 case SCSI_MLQUEUE_DEVICE_BUSY:
142 case SCSI_MLQUEUE_EH_RETRY:
143 device->device_blocked = device->max_device_blocked;
145 case SCSI_MLQUEUE_TARGET_BUSY:
146 starget->target_blocked = starget->max_target_blocked;
151 * Decrement the counters, since these commands are no longer
152 * active on the host/device.
155 scsi_device_unbusy(device);
158 * Requeue this command. It will go before all other commands
159 * that are already in the queue. Schedule requeue work under
160 * lock such that the kblockd_schedule_work() call happens
161 * before blk_cleanup_queue() finishes.
163 spin_lock_irqsave(q->queue_lock, flags);
164 blk_requeue_request(q, cmd->request);
165 kblockd_schedule_work(q, &device->requeue_work);
166 spin_unlock_irqrestore(q->queue_lock, flags);
170 * Function: scsi_queue_insert()
172 * Purpose: Insert a command in the midlevel queue.
174 * Arguments: cmd - command that we are adding to queue.
175 * reason - why we are inserting command to queue.
177 * Lock status: Assumed that lock is not held upon entry.
181 * Notes: We do this for one of two cases. Either the host is busy
182 * and it cannot accept any more commands for the time being,
183 * or the device returned QUEUE_FULL and can accept no more
185 * Notes: This could be called either from an interrupt context or a
186 * normal process context.
188 void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
190 __scsi_queue_insert(cmd, reason, 1);
193 * scsi_execute - insert request and wait for the result
196 * @data_direction: data direction
197 * @buffer: data buffer
198 * @bufflen: len of buffer
199 * @sense: optional sense buffer
200 * @timeout: request timeout in seconds
201 * @retries: number of times to retry request
202 * @flags: or into request flags;
203 * @resid: optional residual length
205 * returns the req->errors value which is the scsi_cmnd result
208 int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
209 int data_direction, void *buffer, unsigned bufflen,
210 unsigned char *sense, int timeout, int retries, int flags,
214 int write = (data_direction == DMA_TO_DEVICE);
215 int ret = DRIVER_ERROR << 24;
217 req = blk_get_request(sdev->request_queue, write, __GFP_WAIT);
221 if (bufflen && blk_rq_map_kern(sdev->request_queue, req,
222 buffer, bufflen, __GFP_WAIT))
225 req->cmd_len = COMMAND_SIZE(cmd[0]);
226 memcpy(req->cmd, cmd, req->cmd_len);
229 req->retries = retries;
230 req->timeout = timeout;
231 req->cmd_type = REQ_TYPE_BLOCK_PC;
232 req->cmd_flags |= flags | REQ_QUIET | REQ_PREEMPT;
235 * head injection *required* here otherwise quiesce won't work
237 blk_execute_rq(req->q, NULL, req, 1);
240 * Some devices (USB mass-storage in particular) may transfer
241 * garbage data together with a residue indicating that the data
242 * is invalid. Prevent the garbage from being misinterpreted
243 * and prevent security leaks by zeroing out the excess data.
245 if (unlikely(req->resid_len > 0 && req->resid_len <= bufflen))
246 memset(buffer + (bufflen - req->resid_len), 0, req->resid_len);
249 *resid = req->resid_len;
252 blk_put_request(req);
256 EXPORT_SYMBOL(scsi_execute);
258 int scsi_execute_req_flags(struct scsi_device *sdev, const unsigned char *cmd,
259 int data_direction, void *buffer, unsigned bufflen,
260 struct scsi_sense_hdr *sshdr, int timeout, int retries,
261 int *resid, int flags)
267 sense = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO);
269 return DRIVER_ERROR << 24;
271 result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen,
272 sense, timeout, retries, flags, resid);
274 scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr);
279 EXPORT_SYMBOL(scsi_execute_req_flags);
282 * Function: scsi_init_cmd_errh()
284 * Purpose: Initialize cmd fields related to error handling.
286 * Arguments: cmd - command that is ready to be queued.
288 * Notes: This function has the job of initializing a number of
289 * fields related to error handling. Typically this will
290 * be called once for each command, as required.
292 static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
294 cmd->serial_number = 0;
295 scsi_set_resid(cmd, 0);
296 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
297 if (cmd->cmd_len == 0)
298 cmd->cmd_len = scsi_command_size(cmd->cmnd);
301 void scsi_device_unbusy(struct scsi_device *sdev)
303 struct Scsi_Host *shost = sdev->host;
304 struct scsi_target *starget = scsi_target(sdev);
307 spin_lock_irqsave(shost->host_lock, flags);
309 starget->target_busy--;
310 if (unlikely(scsi_host_in_recovery(shost) &&
311 (shost->host_failed || shost->host_eh_scheduled)))
312 scsi_eh_wakeup(shost);
313 spin_unlock(shost->host_lock);
314 spin_lock(sdev->request_queue->queue_lock);
316 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
320 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
321 * and call blk_run_queue for all the scsi_devices on the target -
322 * including current_sdev first.
324 * Called with *no* scsi locks held.
326 static void scsi_single_lun_run(struct scsi_device *current_sdev)
328 struct Scsi_Host *shost = current_sdev->host;
329 struct scsi_device *sdev, *tmp;
330 struct scsi_target *starget = scsi_target(current_sdev);
333 spin_lock_irqsave(shost->host_lock, flags);
334 starget->starget_sdev_user = NULL;
335 spin_unlock_irqrestore(shost->host_lock, flags);
338 * Call blk_run_queue for all LUNs on the target, starting with
339 * current_sdev. We race with others (to set starget_sdev_user),
340 * but in most cases, we will be first. Ideally, each LU on the
341 * target would get some limited time or requests on the target.
343 blk_run_queue(current_sdev->request_queue);
345 spin_lock_irqsave(shost->host_lock, flags);
346 if (starget->starget_sdev_user)
348 list_for_each_entry_safe(sdev, tmp, &starget->devices,
349 same_target_siblings) {
350 if (sdev == current_sdev)
352 if (scsi_device_get(sdev))
355 spin_unlock_irqrestore(shost->host_lock, flags);
356 blk_run_queue(sdev->request_queue);
357 spin_lock_irqsave(shost->host_lock, flags);
359 scsi_device_put(sdev);
362 spin_unlock_irqrestore(shost->host_lock, flags);
365 static inline int scsi_device_is_busy(struct scsi_device *sdev)
367 if (sdev->device_busy >= sdev->queue_depth || sdev->device_blocked)
373 static inline int scsi_target_is_busy(struct scsi_target *starget)
375 return ((starget->can_queue > 0 &&
376 starget->target_busy >= starget->can_queue) ||
377 starget->target_blocked);
380 static inline int scsi_host_is_busy(struct Scsi_Host *shost)
382 if ((shost->can_queue > 0 && shost->host_busy >= shost->can_queue) ||
383 shost->host_blocked || shost->host_self_blocked)
389 static void scsi_starved_list_run(struct Scsi_Host *shost)
391 LIST_HEAD(starved_list);
392 struct scsi_device *sdev;
395 spin_lock_irqsave(shost->host_lock, flags);
396 list_splice_init(&shost->starved_list, &starved_list);
398 while (!list_empty(&starved_list)) {
399 struct request_queue *slq;
402 * As long as shost is accepting commands and we have
403 * starved queues, call blk_run_queue. scsi_request_fn
404 * drops the queue_lock and can add us back to the
407 * host_lock protects the starved_list and starved_entry.
408 * scsi_request_fn must get the host_lock before checking
409 * or modifying starved_list or starved_entry.
411 if (scsi_host_is_busy(shost))
414 sdev = list_entry(starved_list.next,
415 struct scsi_device, starved_entry);
416 list_del_init(&sdev->starved_entry);
417 if (scsi_target_is_busy(scsi_target(sdev))) {
418 list_move_tail(&sdev->starved_entry,
419 &shost->starved_list);
424 * Once we drop the host lock, a racing scsi_remove_device()
425 * call may remove the sdev from the starved list and destroy
426 * it and the queue. Mitigate by taking a reference to the
427 * queue and never touching the sdev again after we drop the
428 * host lock. Note: if __scsi_remove_device() invokes
429 * blk_cleanup_queue() before the queue is run from this
430 * function then blk_run_queue() will return immediately since
431 * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING.
433 slq = sdev->request_queue;
434 if (!blk_get_queue(slq))
436 spin_unlock_irqrestore(shost->host_lock, flags);
441 spin_lock_irqsave(shost->host_lock, flags);
443 /* put any unprocessed entries back */
444 list_splice(&starved_list, &shost->starved_list);
445 spin_unlock_irqrestore(shost->host_lock, flags);
449 * Function: scsi_run_queue()
451 * Purpose: Select a proper request queue to serve next
453 * Arguments: q - last request's queue
457 * Notes: The previous command was completely finished, start
458 * a new one if possible.
460 static void scsi_run_queue(struct request_queue *q)
462 struct scsi_device *sdev = q->queuedata;
464 if (scsi_target(sdev)->single_lun)
465 scsi_single_lun_run(sdev);
466 if (!list_empty(&sdev->host->starved_list))
467 scsi_starved_list_run(sdev->host);
472 void scsi_requeue_run_queue(struct work_struct *work)
474 struct scsi_device *sdev;
475 struct request_queue *q;
477 sdev = container_of(work, struct scsi_device, requeue_work);
478 q = sdev->request_queue;
483 * Function: scsi_requeue_command()
485 * Purpose: Handle post-processing of completed commands.
487 * Arguments: q - queue to operate on
488 * cmd - command that may need to be requeued.
492 * Notes: After command completion, there may be blocks left
493 * over which weren't finished by the previous command
494 * this can be for a number of reasons - the main one is
495 * I/O errors in the middle of the request, in which case
496 * we need to request the blocks that come after the bad
498 * Notes: Upon return, cmd is a stale pointer.
500 static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd)
502 struct scsi_device *sdev = cmd->device;
503 struct request *req = cmd->request;
507 * We need to hold a reference on the device to avoid the queue being
508 * killed after the unlock and before scsi_run_queue is invoked which
509 * may happen because scsi_unprep_request() puts the command which
510 * releases its reference on the device.
512 get_device(&sdev->sdev_gendev);
514 spin_lock_irqsave(q->queue_lock, flags);
515 scsi_unprep_request(req);
516 blk_requeue_request(q, req);
517 spin_unlock_irqrestore(q->queue_lock, flags);
521 put_device(&sdev->sdev_gendev);
524 void scsi_next_command(struct scsi_cmnd *cmd)
526 struct scsi_device *sdev = cmd->device;
527 struct request_queue *q = sdev->request_queue;
529 /* need to hold a reference on the device before we let go of the cmd */
530 get_device(&sdev->sdev_gendev);
532 scsi_put_command(cmd);
533 put_device(&sdev->sdev_gendev);
536 /* ok to remove device now */
537 put_device(&sdev->sdev_gendev);
540 void scsi_run_host_queues(struct Scsi_Host *shost)
542 struct scsi_device *sdev;
544 shost_for_each_device(sdev, shost)
545 scsi_run_queue(sdev->request_queue);
548 static void __scsi_release_buffers(struct scsi_cmnd *, int);
551 * Function: scsi_end_request()
553 * Purpose: Post-processing of completed commands (usually invoked at end
554 * of upper level post-processing and scsi_io_completion).
556 * Arguments: cmd - command that is complete.
557 * error - 0 if I/O indicates success, < 0 for I/O error.
558 * bytes - number of bytes of completed I/O
559 * requeue - indicates whether we should requeue leftovers.
561 * Lock status: Assumed that lock is not held upon entry.
563 * Returns: cmd if requeue required, NULL otherwise.
565 * Notes: This is called for block device requests in order to
566 * mark some number of sectors as complete.
568 * We are guaranteeing that the request queue will be goosed
569 * at some point during this call.
570 * Notes: If cmd was requeued, upon return it will be a stale pointer.
572 static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int error,
573 int bytes, int requeue)
575 struct request_queue *q = cmd->device->request_queue;
576 struct request *req = cmd->request;
579 * If there are blocks left over at the end, set up the command
580 * to queue the remainder of them.
582 if (blk_end_request(req, error, bytes)) {
583 /* kill remainder if no retrys */
584 if (error && scsi_noretry_cmd(cmd))
585 blk_end_request_all(req, error);
589 * Bleah. Leftovers again. Stick the
590 * leftovers in the front of the
591 * queue, and goose the queue again.
593 scsi_release_buffers(cmd);
594 scsi_requeue_command(q, cmd);
602 * This will goose the queue request function at the end, so we don't
603 * need to worry about launching another command.
605 __scsi_release_buffers(cmd, 0);
606 scsi_next_command(cmd);
610 static inline unsigned int scsi_sgtable_index(unsigned short nents)
614 BUG_ON(nents > SCSI_MAX_SG_SEGMENTS);
619 index = get_count_order(nents) - 3;
624 static void scsi_sg_free(struct scatterlist *sgl, unsigned int nents)
626 struct scsi_host_sg_pool *sgp;
628 sgp = scsi_sg_pools + scsi_sgtable_index(nents);
629 mempool_free(sgl, sgp->pool);
632 static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask)
634 struct scsi_host_sg_pool *sgp;
636 sgp = scsi_sg_pools + scsi_sgtable_index(nents);
637 return mempool_alloc(sgp->pool, gfp_mask);
640 static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents,
647 ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS,
648 gfp_mask, scsi_sg_alloc);
650 __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS,
656 static void scsi_free_sgtable(struct scsi_data_buffer *sdb)
658 __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free);
661 static void __scsi_release_buffers(struct scsi_cmnd *cmd, int do_bidi_check)
664 if (cmd->sdb.table.nents)
665 scsi_free_sgtable(&cmd->sdb);
667 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
669 if (do_bidi_check && scsi_bidi_cmnd(cmd)) {
670 struct scsi_data_buffer *bidi_sdb =
671 cmd->request->next_rq->special;
672 scsi_free_sgtable(bidi_sdb);
673 kmem_cache_free(scsi_sdb_cache, bidi_sdb);
674 cmd->request->next_rq->special = NULL;
677 if (scsi_prot_sg_count(cmd))
678 scsi_free_sgtable(cmd->prot_sdb);
682 * Function: scsi_release_buffers()
684 * Purpose: Completion processing for block device I/O requests.
686 * Arguments: cmd - command that we are bailing.
688 * Lock status: Assumed that no lock is held upon entry.
692 * Notes: In the event that an upper level driver rejects a
693 * command, we must release resources allocated during
694 * the __init_io() function. Primarily this would involve
695 * the scatter-gather table, and potentially any bounce
698 void scsi_release_buffers(struct scsi_cmnd *cmd)
700 __scsi_release_buffers(cmd, 1);
702 EXPORT_SYMBOL(scsi_release_buffers);
705 * __scsi_error_from_host_byte - translate SCSI error code into errno
706 * @cmd: SCSI command (unused)
707 * @result: scsi error code
709 * Translate SCSI error code into standard UNIX errno.
711 * -ENOLINK temporary transport failure
712 * -EREMOTEIO permanent target failure, do not retry
713 * -EBADE permanent nexus failure, retry on other path
714 * -ENOSPC No write space available
715 * -ENODATA Medium error
716 * -EIO unspecified I/O error
718 static int __scsi_error_from_host_byte(struct scsi_cmnd *cmd, int result)
722 switch(host_byte(result)) {
723 case DID_TRANSPORT_FAILFAST:
726 case DID_TARGET_FAILURE:
727 set_host_byte(cmd, DID_OK);
730 case DID_NEXUS_FAILURE:
731 set_host_byte(cmd, DID_OK);
734 case DID_ALLOC_FAILURE:
735 set_host_byte(cmd, DID_OK);
738 case DID_MEDIUM_ERROR:
739 set_host_byte(cmd, DID_OK);
751 * Function: scsi_io_completion()
753 * Purpose: Completion processing for block device I/O requests.
755 * Arguments: cmd - command that is finished.
757 * Lock status: Assumed that no lock is held upon entry.
761 * Notes: This function is matched in terms of capabilities to
762 * the function that created the scatter-gather list.
763 * In other words, if there are no bounce buffers
764 * (the normal case for most drivers), we don't need
765 * the logic to deal with cleaning up afterwards.
767 * We must call scsi_end_request(). This will finish off
768 * the specified number of sectors. If we are done, the
769 * command block will be released and the queue function
770 * will be goosed. If we are not done then we have to
771 * figure out what to do next:
773 * a) We can call scsi_requeue_command(). The request
774 * will be unprepared and put back on the queue. Then
775 * a new command will be created for it. This should
776 * be used if we made forward progress, or if we want
777 * to switch from READ(10) to READ(6) for example.
779 * b) We can call scsi_queue_insert(). The request will
780 * be put back on the queue and retried using the same
781 * command as before, possibly after a delay.
783 * c) We can call blk_end_request() with -EIO to fail
784 * the remainder of the request.
786 void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
788 int result = cmd->result;
789 struct request_queue *q = cmd->device->request_queue;
790 struct request *req = cmd->request;
792 struct scsi_sense_hdr sshdr;
794 int sense_deferred = 0;
795 enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,
796 ACTION_DELAYED_RETRY} action;
797 char *description = NULL;
798 unsigned long wait_for = (cmd->allowed + 1) * req->timeout;
801 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
803 sense_deferred = scsi_sense_is_deferred(&sshdr);
806 if (req->cmd_type == REQ_TYPE_BLOCK_PC) { /* SG_IO ioctl from block level */
808 if (sense_valid && req->sense) {
810 * SG_IO wants current and deferred errors
812 int len = 8 + cmd->sense_buffer[7];
814 if (len > SCSI_SENSE_BUFFERSIZE)
815 len = SCSI_SENSE_BUFFERSIZE;
816 memcpy(req->sense, cmd->sense_buffer, len);
817 req->sense_len = len;
820 error = __scsi_error_from_host_byte(cmd, result);
823 * __scsi_error_from_host_byte may have reset the host_byte
825 req->errors = cmd->result;
827 req->resid_len = scsi_get_resid(cmd);
829 if (scsi_bidi_cmnd(cmd)) {
831 * Bidi commands Must be complete as a whole,
832 * both sides at once.
834 req->next_rq->resid_len = scsi_in(cmd)->resid;
836 scsi_release_buffers(cmd);
837 blk_end_request_all(req, 0);
839 scsi_next_command(cmd);
844 /* no bidi support for !REQ_TYPE_BLOCK_PC yet */
845 BUG_ON(blk_bidi_rq(req));
848 * Next deal with any sectors which we were able to correctly
851 SCSI_LOG_HLCOMPLETE(1, printk("%u sectors total, "
853 blk_rq_sectors(req), good_bytes));
856 * Recovered errors need reporting, but they're always treated
857 * as success, so fiddle the result code here. For BLOCK_PC
858 * we already took a copy of the original into rq->errors which
859 * is what gets returned to the user
861 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
862 /* if ATA PASS-THROUGH INFORMATION AVAILABLE skip
863 * print since caller wants ATA registers. Only occurs on
864 * SCSI ATA PASS_THROUGH commands when CK_COND=1
866 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
868 else if (!(req->cmd_flags & REQ_QUIET))
869 scsi_print_sense("", cmd);
871 /* BLOCK_PC may have set error */
876 * A number of bytes were successfully read. If there
877 * are leftovers and there is some kind of error
878 * (result != 0), retry the rest.
880 if (scsi_end_request(cmd, error, good_bytes, result == 0) == NULL)
883 error = __scsi_error_from_host_byte(cmd, result);
885 if (host_byte(result) == DID_RESET) {
886 /* Third party bus reset or reset for error recovery
887 * reasons. Just retry the command and see what
890 action = ACTION_RETRY;
891 } else if (sense_valid && !sense_deferred) {
892 switch (sshdr.sense_key) {
894 if (cmd->device->removable) {
895 /* Detected disc change. Set a bit
896 * and quietly refuse further access.
898 cmd->device->changed = 1;
899 description = "Media Changed";
900 action = ACTION_FAIL;
902 /* Must have been a power glitch, or a
903 * bus reset. Could not have been a
904 * media change, so we just retry the
905 * command and see what happens.
907 action = ACTION_RETRY;
910 case ILLEGAL_REQUEST:
911 /* If we had an ILLEGAL REQUEST returned, then
912 * we may have performed an unsupported
913 * command. The only thing this should be
914 * would be a ten byte read where only a six
915 * byte read was supported. Also, on a system
916 * where READ CAPACITY failed, we may have
917 * read past the end of the disk.
919 if ((cmd->device->use_10_for_rw &&
920 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
921 (cmd->cmnd[0] == READ_10 ||
922 cmd->cmnd[0] == WRITE_10)) {
923 /* This will issue a new 6-byte command. */
924 cmd->device->use_10_for_rw = 0;
925 action = ACTION_REPREP;
926 } else if (sshdr.asc == 0x10) /* DIX */ {
927 description = "Host Data Integrity Failure";
928 action = ACTION_FAIL;
930 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
931 } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
932 switch (cmd->cmnd[0]) {
934 description = "Discard failure";
938 if (cmd->cmnd[1] & 0x8)
939 description = "Discard failure";
942 "Write same failure";
945 description = "Invalid command failure";
948 action = ACTION_FAIL;
951 action = ACTION_FAIL;
953 case ABORTED_COMMAND:
954 action = ACTION_FAIL;
955 if (sshdr.asc == 0x10) { /* DIF */
956 description = "Target Data Integrity Failure";
961 /* If the device is in the process of becoming
962 * ready, or has a temporary blockage, retry.
964 if (sshdr.asc == 0x04) {
965 switch (sshdr.ascq) {
966 case 0x01: /* becoming ready */
967 case 0x04: /* format in progress */
968 case 0x05: /* rebuild in progress */
969 case 0x06: /* recalculation in progress */
970 case 0x07: /* operation in progress */
971 case 0x08: /* Long write in progress */
972 case 0x09: /* self test in progress */
973 case 0x14: /* space allocation in progress */
974 action = ACTION_DELAYED_RETRY;
977 description = "Device not ready";
978 action = ACTION_FAIL;
982 description = "Device not ready";
983 action = ACTION_FAIL;
986 case VOLUME_OVERFLOW:
987 /* See SSC3rXX or current. */
988 action = ACTION_FAIL;
991 description = "Unhandled sense code";
992 action = ACTION_FAIL;
996 description = "Unhandled error code";
997 action = ACTION_FAIL;
1000 if (action != ACTION_FAIL &&
1001 time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
1002 action = ACTION_FAIL;
1003 description = "Command timed out";
1008 /* Give up and fail the remainder of the request */
1009 scsi_release_buffers(cmd);
1010 if (!(req->cmd_flags & REQ_QUIET)) {
1012 scmd_printk(KERN_INFO, cmd, "%s\n",
1014 scsi_print_result(cmd);
1015 if (driver_byte(result) & DRIVER_SENSE)
1016 scsi_print_sense("", cmd);
1017 scsi_print_command(cmd);
1019 if (blk_end_request_err(req, error))
1020 scsi_requeue_command(q, cmd);
1022 scsi_next_command(cmd);
1025 /* Unprep the request and put it back at the head of the queue.
1026 * A new command will be prepared and issued.
1028 scsi_release_buffers(cmd);
1029 scsi_requeue_command(q, cmd);
1032 /* Retry the same command immediately */
1033 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, 0);
1035 case ACTION_DELAYED_RETRY:
1036 /* Retry the same command after a delay */
1037 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, 0);
1042 static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb,
1048 * If sg table allocation fails, requeue request later.
1050 if (unlikely(scsi_alloc_sgtable(sdb, req->nr_phys_segments,
1052 return BLKPREP_DEFER;
1058 * Next, walk the list, and fill in the addresses and sizes of
1061 count = blk_rq_map_sg(req->q, req, sdb->table.sgl);
1062 BUG_ON(count > sdb->table.nents);
1063 sdb->table.nents = count;
1064 sdb->length = blk_rq_bytes(req);
1069 * Function: scsi_init_io()
1071 * Purpose: SCSI I/O initialize function.
1073 * Arguments: cmd - Command descriptor we wish to initialize
1075 * Returns: 0 on success
1076 * BLKPREP_DEFER if the failure is retryable
1077 * BLKPREP_KILL if the failure is fatal
1079 int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask)
1081 struct request *rq = cmd->request;
1083 int error = scsi_init_sgtable(rq, &cmd->sdb, gfp_mask);
1087 if (blk_bidi_rq(rq)) {
1088 struct scsi_data_buffer *bidi_sdb = kmem_cache_zalloc(
1089 scsi_sdb_cache, GFP_ATOMIC);
1091 error = BLKPREP_DEFER;
1095 rq->next_rq->special = bidi_sdb;
1096 error = scsi_init_sgtable(rq->next_rq, bidi_sdb, GFP_ATOMIC);
1101 if (blk_integrity_rq(rq)) {
1102 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1105 BUG_ON(prot_sdb == NULL);
1106 ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
1108 if (scsi_alloc_sgtable(prot_sdb, ivecs, gfp_mask)) {
1109 error = BLKPREP_DEFER;
1113 count = blk_rq_map_integrity_sg(rq->q, rq->bio,
1114 prot_sdb->table.sgl);
1115 BUG_ON(unlikely(count > ivecs));
1116 BUG_ON(unlikely(count > queue_max_integrity_segments(rq->q)));
1118 cmd->prot_sdb = prot_sdb;
1119 cmd->prot_sdb->table.nents = count;
1125 scsi_release_buffers(cmd);
1126 cmd->request->special = NULL;
1127 scsi_put_command(cmd);
1128 put_device(&cmd->device->sdev_gendev);
1131 EXPORT_SYMBOL(scsi_init_io);
1133 static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev,
1134 struct request *req)
1136 struct scsi_cmnd *cmd;
1138 if (!req->special) {
1139 /* Bail if we can't get a reference to the device */
1140 if (!get_device(&sdev->sdev_gendev))
1143 cmd = scsi_get_command(sdev, GFP_ATOMIC);
1144 if (unlikely(!cmd)) {
1145 put_device(&sdev->sdev_gendev);
1153 /* pull a tag out of the request if we have one */
1154 cmd->tag = req->tag;
1157 cmd->cmnd = req->cmd;
1158 cmd->prot_op = SCSI_PROT_NORMAL;
1163 int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
1165 struct scsi_cmnd *cmd;
1166 int ret = scsi_prep_state_check(sdev, req);
1168 if (ret != BLKPREP_OK)
1171 cmd = scsi_get_cmd_from_req(sdev, req);
1173 return BLKPREP_DEFER;
1176 * BLOCK_PC requests may transfer data, in which case they must
1177 * a bio attached to them. Or they might contain a SCSI command
1178 * that does not transfer data, in which case they may optionally
1179 * submit a request without an attached bio.
1184 BUG_ON(!req->nr_phys_segments);
1186 ret = scsi_init_io(cmd, GFP_ATOMIC);
1190 BUG_ON(blk_rq_bytes(req));
1192 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1196 cmd->cmd_len = req->cmd_len;
1197 if (!blk_rq_bytes(req))
1198 cmd->sc_data_direction = DMA_NONE;
1199 else if (rq_data_dir(req) == WRITE)
1200 cmd->sc_data_direction = DMA_TO_DEVICE;
1202 cmd->sc_data_direction = DMA_FROM_DEVICE;
1204 cmd->transfersize = blk_rq_bytes(req);
1205 cmd->allowed = req->retries;
1208 EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd);
1211 * Setup a REQ_TYPE_FS command. These are simple read/write request
1212 * from filesystems that still need to be translated to SCSI CDBs from
1215 int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
1217 struct scsi_cmnd *cmd;
1218 int ret = scsi_prep_state_check(sdev, req);
1220 if (ret != BLKPREP_OK)
1223 if (unlikely(sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh
1224 && sdev->scsi_dh_data->scsi_dh->prep_fn)) {
1225 ret = sdev->scsi_dh_data->scsi_dh->prep_fn(sdev, req);
1226 if (ret != BLKPREP_OK)
1231 * Filesystem requests must transfer data.
1233 BUG_ON(!req->nr_phys_segments);
1235 cmd = scsi_get_cmd_from_req(sdev, req);
1237 return BLKPREP_DEFER;
1239 memset(cmd->cmnd, 0, BLK_MAX_CDB);
1240 return scsi_init_io(cmd, GFP_ATOMIC);
1242 EXPORT_SYMBOL(scsi_setup_fs_cmnd);
1244 int scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
1246 int ret = BLKPREP_OK;
1249 * If the device is not in running state we will reject some
1252 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
1253 switch (sdev->sdev_state) {
1255 case SDEV_TRANSPORT_OFFLINE:
1257 * If the device is offline we refuse to process any
1258 * commands. The device must be brought online
1259 * before trying any recovery commands.
1261 sdev_printk(KERN_ERR, sdev,
1262 "rejecting I/O to offline device\n");
1267 * If the device is fully deleted, we refuse to
1268 * process any commands as well.
1270 sdev_printk(KERN_ERR, sdev,
1271 "rejecting I/O to dead device\n");
1276 case SDEV_CREATED_BLOCK:
1278 * If the devices is blocked we defer normal commands.
1280 if (!(req->cmd_flags & REQ_PREEMPT))
1281 ret = BLKPREP_DEFER;
1285 * For any other not fully online state we only allow
1286 * special commands. In particular any user initiated
1287 * command is not allowed.
1289 if (!(req->cmd_flags & REQ_PREEMPT))
1296 EXPORT_SYMBOL(scsi_prep_state_check);
1298 int scsi_prep_return(struct request_queue *q, struct request *req, int ret)
1300 struct scsi_device *sdev = q->queuedata;
1304 req->errors = DID_NO_CONNECT << 16;
1305 /* release the command and kill it */
1307 struct scsi_cmnd *cmd = req->special;
1308 scsi_release_buffers(cmd);
1309 scsi_put_command(cmd);
1310 put_device(&cmd->device->sdev_gendev);
1311 req->special = NULL;
1316 * If we defer, the blk_peek_request() returns NULL, but the
1317 * queue must be restarted, so we schedule a callback to happen
1320 if (sdev->device_busy == 0)
1321 blk_delay_queue(q, SCSI_QUEUE_DELAY);
1324 req->cmd_flags |= REQ_DONTPREP;
1329 EXPORT_SYMBOL(scsi_prep_return);
1331 int scsi_prep_fn(struct request_queue *q, struct request *req)
1333 struct scsi_device *sdev = q->queuedata;
1334 int ret = BLKPREP_KILL;
1336 if (req->cmd_type == REQ_TYPE_BLOCK_PC)
1337 ret = scsi_setup_blk_pc_cmnd(sdev, req);
1338 return scsi_prep_return(q, req, ret);
1340 EXPORT_SYMBOL(scsi_prep_fn);
1343 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1346 * Called with the queue_lock held.
1348 static inline int scsi_dev_queue_ready(struct request_queue *q,
1349 struct scsi_device *sdev)
1351 if (sdev->device_busy == 0 && sdev->device_blocked) {
1353 * unblock after device_blocked iterates to zero
1355 if (--sdev->device_blocked == 0) {
1357 sdev_printk(KERN_INFO, sdev,
1358 "unblocking device at zero depth\n"));
1360 blk_delay_queue(q, SCSI_QUEUE_DELAY);
1364 if (scsi_device_is_busy(sdev))
1372 * scsi_target_queue_ready: checks if there we can send commands to target
1373 * @sdev: scsi device on starget to check.
1375 * Called with the host lock held.
1377 static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1378 struct scsi_device *sdev)
1380 struct scsi_target *starget = scsi_target(sdev);
1382 if (starget->single_lun) {
1383 if (starget->starget_sdev_user &&
1384 starget->starget_sdev_user != sdev)
1386 starget->starget_sdev_user = sdev;
1389 if (starget->target_busy == 0 && starget->target_blocked) {
1391 * unblock after target_blocked iterates to zero
1393 if (--starget->target_blocked == 0) {
1394 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1395 "unblocking target at zero depth\n"));
1400 if (scsi_target_is_busy(starget)) {
1401 list_move_tail(&sdev->starved_entry, &shost->starved_list);
1409 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1410 * return 0. We must end up running the queue again whenever 0 is
1411 * returned, else IO can hang.
1413 * Called with host_lock held.
1415 static inline int scsi_host_queue_ready(struct request_queue *q,
1416 struct Scsi_Host *shost,
1417 struct scsi_device *sdev)
1419 if (scsi_host_in_recovery(shost))
1421 if (shost->host_busy == 0 && shost->host_blocked) {
1423 * unblock after host_blocked iterates to zero
1425 if (--shost->host_blocked == 0) {
1427 printk("scsi%d unblocking host at zero depth\n",
1433 if (scsi_host_is_busy(shost)) {
1434 if (list_empty(&sdev->starved_entry))
1435 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1439 /* We're OK to process the command, so we can't be starved */
1440 if (!list_empty(&sdev->starved_entry))
1441 list_del_init(&sdev->starved_entry);
1447 * Busy state exporting function for request stacking drivers.
1449 * For efficiency, no lock is taken to check the busy state of
1450 * shost/starget/sdev, since the returned value is not guaranteed and
1451 * may be changed after request stacking drivers call the function,
1452 * regardless of taking lock or not.
1454 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1455 * needs to return 'not busy'. Otherwise, request stacking drivers
1456 * may hold requests forever.
1458 static int scsi_lld_busy(struct request_queue *q)
1460 struct scsi_device *sdev = q->queuedata;
1461 struct Scsi_Host *shost;
1463 if (blk_queue_dying(q))
1469 * Ignore host/starget busy state.
1470 * Since block layer does not have a concept of fairness across
1471 * multiple queues, congestion of host/starget needs to be handled
1474 if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
1481 * Kill a request for a dead device
1483 static void scsi_kill_request(struct request *req, struct request_queue *q)
1485 struct scsi_cmnd *cmd = req->special;
1486 struct scsi_device *sdev;
1487 struct scsi_target *starget;
1488 struct Scsi_Host *shost;
1490 blk_start_request(req);
1492 scmd_printk(KERN_INFO, cmd, "killing request\n");
1495 starget = scsi_target(sdev);
1497 scsi_init_cmd_errh(cmd);
1498 cmd->result = DID_NO_CONNECT << 16;
1499 atomic_inc(&cmd->device->iorequest_cnt);
1502 * SCSI request completion path will do scsi_device_unbusy(),
1503 * bump busy counts. To bump the counters, we need to dance
1504 * with the locks as normal issue path does.
1506 sdev->device_busy++;
1507 spin_unlock(sdev->request_queue->queue_lock);
1508 spin_lock(shost->host_lock);
1510 starget->target_busy++;
1511 spin_unlock(shost->host_lock);
1512 spin_lock(sdev->request_queue->queue_lock);
1514 blk_complete_request(req);
1517 static void scsi_softirq_done(struct request *rq)
1519 struct scsi_cmnd *cmd = rq->special;
1520 unsigned long wait_for = (cmd->allowed + 1) * rq->timeout;
1523 INIT_LIST_HEAD(&cmd->eh_entry);
1525 atomic_inc(&cmd->device->iodone_cnt);
1527 atomic_inc(&cmd->device->ioerr_cnt);
1529 disposition = scsi_decide_disposition(cmd);
1530 if (disposition != SUCCESS &&
1531 time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
1532 sdev_printk(KERN_ERR, cmd->device,
1533 "timing out command, waited %lus\n",
1535 disposition = SUCCESS;
1538 scsi_log_completion(cmd, disposition);
1540 switch (disposition) {
1542 scsi_finish_command(cmd);
1545 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
1547 case ADD_TO_MLQUEUE:
1548 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1551 if (!scsi_eh_scmd_add(cmd, 0))
1552 scsi_finish_command(cmd);
1557 * Function: scsi_request_fn()
1559 * Purpose: Main strategy routine for SCSI.
1561 * Arguments: q - Pointer to actual queue.
1565 * Lock status: IO request lock assumed to be held when called.
1567 static void scsi_request_fn(struct request_queue *q)
1568 __releases(q->queue_lock)
1569 __acquires(q->queue_lock)
1571 struct scsi_device *sdev = q->queuedata;
1572 struct Scsi_Host *shost;
1573 struct scsi_cmnd *cmd;
1574 struct request *req;
1577 * To start with, we keep looping until the queue is empty, or until
1578 * the host is no longer able to accept any more requests.
1584 * get next queueable request. We do this early to make sure
1585 * that the request is fully prepared even if we cannot
1588 req = blk_peek_request(q);
1589 if (!req || !scsi_dev_queue_ready(q, sdev))
1592 if (unlikely(!scsi_device_online(sdev))) {
1593 sdev_printk(KERN_ERR, sdev,
1594 "rejecting I/O to offline device\n");
1595 scsi_kill_request(req, q);
1601 * Remove the request from the request list.
1603 if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req)))
1604 blk_start_request(req);
1605 sdev->device_busy++;
1607 spin_unlock(q->queue_lock);
1609 if (unlikely(cmd == NULL)) {
1610 printk(KERN_CRIT "impossible request in %s.\n"
1611 "please mail a stack trace to "
1612 "linux-scsi@vger.kernel.org\n",
1614 blk_dump_rq_flags(req, "foo");
1617 spin_lock(shost->host_lock);
1620 * We hit this when the driver is using a host wide
1621 * tag map. For device level tag maps the queue_depth check
1622 * in the device ready fn would prevent us from trying
1623 * to allocate a tag. Since the map is a shared host resource
1624 * we add the dev to the starved list so it eventually gets
1625 * a run when a tag is freed.
1627 if (blk_queue_tagged(q) && !blk_rq_tagged(req)) {
1628 if (list_empty(&sdev->starved_entry))
1629 list_add_tail(&sdev->starved_entry,
1630 &shost->starved_list);
1634 if (!scsi_target_queue_ready(shost, sdev))
1637 if (!scsi_host_queue_ready(q, shost, sdev))
1640 scsi_target(sdev)->target_busy++;
1644 * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will
1645 * take the lock again.
1647 spin_unlock_irq(shost->host_lock);
1650 * Finally, initialize any error handling parameters, and set up
1651 * the timers for timeouts.
1653 scsi_init_cmd_errh(cmd);
1656 * Dispatch the command to the low-level driver.
1658 rtn = scsi_dispatch_cmd(cmd);
1659 spin_lock_irq(q->queue_lock);
1667 spin_unlock_irq(shost->host_lock);
1670 * lock q, handle tag, requeue req, and decrement device_busy. We
1671 * must return with queue_lock held.
1673 * Decrementing device_busy without checking it is OK, as all such
1674 * cases (host limits or settings) should run the queue at some
1677 spin_lock_irq(q->queue_lock);
1678 blk_requeue_request(q, req);
1679 sdev->device_busy--;
1681 if (sdev->device_busy == 0)
1682 blk_delay_queue(q, SCSI_QUEUE_DELAY);
1685 u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost)
1687 struct device *host_dev;
1688 u64 bounce_limit = 0xffffffff;
1690 if (shost->unchecked_isa_dma)
1691 return BLK_BOUNCE_ISA;
1693 * Platforms with virtual-DMA translation
1694 * hardware have no practical limit.
1696 if (!PCI_DMA_BUS_IS_PHYS)
1697 return BLK_BOUNCE_ANY;
1699 host_dev = scsi_get_device(shost);
1700 if (host_dev && host_dev->dma_mask)
1701 bounce_limit = (u64)dma_max_pfn(host_dev) << PAGE_SHIFT;
1703 return bounce_limit;
1705 EXPORT_SYMBOL(scsi_calculate_bounce_limit);
1707 struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost,
1708 request_fn_proc *request_fn)
1710 struct request_queue *q;
1711 struct device *dev = shost->dma_dev;
1713 q = blk_init_queue(request_fn, NULL);
1718 * this limit is imposed by hardware restrictions
1720 blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
1721 SCSI_MAX_SG_CHAIN_SEGMENTS));
1723 if (scsi_host_prot_dma(shost)) {
1724 shost->sg_prot_tablesize =
1725 min_not_zero(shost->sg_prot_tablesize,
1726 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
1727 BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
1728 blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
1731 blk_queue_max_hw_sectors(q, shost->max_sectors);
1732 blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost));
1733 blk_queue_segment_boundary(q, shost->dma_boundary);
1734 dma_set_seg_boundary(dev, shost->dma_boundary);
1736 blk_queue_max_segment_size(q, dma_get_max_seg_size(dev));
1738 if (!shost->use_clustering)
1739 q->limits.cluster = 0;
1742 * set a reasonable default alignment on word boundaries: the
1743 * host and device may alter it using
1744 * blk_queue_update_dma_alignment() later.
1746 blk_queue_dma_alignment(q, 0x03);
1750 EXPORT_SYMBOL(__scsi_alloc_queue);
1752 struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
1754 struct request_queue *q;
1756 q = __scsi_alloc_queue(sdev->host, scsi_request_fn);
1760 blk_queue_prep_rq(q, scsi_prep_fn);
1761 blk_queue_softirq_done(q, scsi_softirq_done);
1762 blk_queue_rq_timed_out(q, scsi_times_out);
1763 blk_queue_lld_busy(q, scsi_lld_busy);
1768 * Function: scsi_block_requests()
1770 * Purpose: Utility function used by low-level drivers to prevent further
1771 * commands from being queued to the device.
1773 * Arguments: shost - Host in question
1777 * Lock status: No locks are assumed held.
1779 * Notes: There is no timer nor any other means by which the requests
1780 * get unblocked other than the low-level driver calling
1781 * scsi_unblock_requests().
1783 void scsi_block_requests(struct Scsi_Host *shost)
1785 shost->host_self_blocked = 1;
1787 EXPORT_SYMBOL(scsi_block_requests);
1790 * Function: scsi_unblock_requests()
1792 * Purpose: Utility function used by low-level drivers to allow further
1793 * commands from being queued to the device.
1795 * Arguments: shost - Host in question
1799 * Lock status: No locks are assumed held.
1801 * Notes: There is no timer nor any other means by which the requests
1802 * get unblocked other than the low-level driver calling
1803 * scsi_unblock_requests().
1805 * This is done as an API function so that changes to the
1806 * internals of the scsi mid-layer won't require wholesale
1807 * changes to drivers that use this feature.
1809 void scsi_unblock_requests(struct Scsi_Host *shost)
1811 shost->host_self_blocked = 0;
1812 scsi_run_host_queues(shost);
1814 EXPORT_SYMBOL(scsi_unblock_requests);
1816 int __init scsi_init_queue(void)
1820 scsi_sdb_cache = kmem_cache_create("scsi_data_buffer",
1821 sizeof(struct scsi_data_buffer),
1823 if (!scsi_sdb_cache) {
1824 printk(KERN_ERR "SCSI: can't init scsi sdb cache\n");
1828 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1829 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1830 int size = sgp->size * sizeof(struct scatterlist);
1832 sgp->slab = kmem_cache_create(sgp->name, size, 0,
1833 SLAB_HWCACHE_ALIGN, NULL);
1835 printk(KERN_ERR "SCSI: can't init sg slab %s\n",
1840 sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE,
1843 printk(KERN_ERR "SCSI: can't init sg mempool %s\n",
1852 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1853 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1855 mempool_destroy(sgp->pool);
1857 kmem_cache_destroy(sgp->slab);
1859 kmem_cache_destroy(scsi_sdb_cache);
1864 void scsi_exit_queue(void)
1868 kmem_cache_destroy(scsi_sdb_cache);
1870 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1871 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1872 mempool_destroy(sgp->pool);
1873 kmem_cache_destroy(sgp->slab);
1878 * scsi_mode_select - issue a mode select
1879 * @sdev: SCSI device to be queried
1880 * @pf: Page format bit (1 == standard, 0 == vendor specific)
1881 * @sp: Save page bit (0 == don't save, 1 == save)
1882 * @modepage: mode page being requested
1883 * @buffer: request buffer (may not be smaller than eight bytes)
1884 * @len: length of request buffer.
1885 * @timeout: command timeout
1886 * @retries: number of retries before failing
1887 * @data: returns a structure abstracting the mode header data
1888 * @sshdr: place to put sense data (or NULL if no sense to be collected).
1889 * must be SCSI_SENSE_BUFFERSIZE big.
1891 * Returns zero if successful; negative error number or scsi
1896 scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
1897 unsigned char *buffer, int len, int timeout, int retries,
1898 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
1900 unsigned char cmd[10];
1901 unsigned char *real_buffer;
1904 memset(cmd, 0, sizeof(cmd));
1905 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
1907 if (sdev->use_10_for_ms) {
1910 real_buffer = kmalloc(8 + len, GFP_KERNEL);
1913 memcpy(real_buffer + 8, buffer, len);
1917 real_buffer[2] = data->medium_type;
1918 real_buffer[3] = data->device_specific;
1919 real_buffer[4] = data->longlba ? 0x01 : 0;
1921 real_buffer[6] = data->block_descriptor_length >> 8;
1922 real_buffer[7] = data->block_descriptor_length;
1924 cmd[0] = MODE_SELECT_10;
1928 if (len > 255 || data->block_descriptor_length > 255 ||
1932 real_buffer = kmalloc(4 + len, GFP_KERNEL);
1935 memcpy(real_buffer + 4, buffer, len);
1938 real_buffer[1] = data->medium_type;
1939 real_buffer[2] = data->device_specific;
1940 real_buffer[3] = data->block_descriptor_length;
1943 cmd[0] = MODE_SELECT;
1947 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
1948 sshdr, timeout, retries, NULL);
1952 EXPORT_SYMBOL_GPL(scsi_mode_select);
1955 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
1956 * @sdev: SCSI device to be queried
1957 * @dbd: set if mode sense will allow block descriptors to be returned
1958 * @modepage: mode page being requested
1959 * @buffer: request buffer (may not be smaller than eight bytes)
1960 * @len: length of request buffer.
1961 * @timeout: command timeout
1962 * @retries: number of retries before failing
1963 * @data: returns a structure abstracting the mode header data
1964 * @sshdr: place to put sense data (or NULL if no sense to be collected).
1965 * must be SCSI_SENSE_BUFFERSIZE big.
1967 * Returns zero if unsuccessful, or the header offset (either 4
1968 * or 8 depending on whether a six or ten byte command was
1969 * issued) if successful.
1972 scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
1973 unsigned char *buffer, int len, int timeout, int retries,
1974 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
1976 unsigned char cmd[12];
1980 struct scsi_sense_hdr my_sshdr;
1982 memset(data, 0, sizeof(*data));
1983 memset(&cmd[0], 0, 12);
1984 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
1987 /* caller might not be interested in sense, but we need it */
1992 use_10_for_ms = sdev->use_10_for_ms;
1994 if (use_10_for_ms) {
1998 cmd[0] = MODE_SENSE_10;
2005 cmd[0] = MODE_SENSE;
2010 memset(buffer, 0, len);
2012 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
2013 sshdr, timeout, retries, NULL);
2015 /* This code looks awful: what it's doing is making sure an
2016 * ILLEGAL REQUEST sense return identifies the actual command
2017 * byte as the problem. MODE_SENSE commands can return
2018 * ILLEGAL REQUEST if the code page isn't supported */
2020 if (use_10_for_ms && !scsi_status_is_good(result) &&
2021 (driver_byte(result) & DRIVER_SENSE)) {
2022 if (scsi_sense_valid(sshdr)) {
2023 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
2024 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
2026 * Invalid command operation code
2028 sdev->use_10_for_ms = 0;
2034 if(scsi_status_is_good(result)) {
2035 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
2036 (modepage == 6 || modepage == 8))) {
2037 /* Initio breakage? */
2040 data->medium_type = 0;
2041 data->device_specific = 0;
2043 data->block_descriptor_length = 0;
2044 } else if(use_10_for_ms) {
2045 data->length = buffer[0]*256 + buffer[1] + 2;
2046 data->medium_type = buffer[2];
2047 data->device_specific = buffer[3];
2048 data->longlba = buffer[4] & 0x01;
2049 data->block_descriptor_length = buffer[6]*256
2052 data->length = buffer[0] + 1;
2053 data->medium_type = buffer[1];
2054 data->device_specific = buffer[2];
2055 data->block_descriptor_length = buffer[3];
2057 data->header_length = header_length;
2062 EXPORT_SYMBOL(scsi_mode_sense);
2065 * scsi_test_unit_ready - test if unit is ready
2066 * @sdev: scsi device to change the state of.
2067 * @timeout: command timeout
2068 * @retries: number of retries before failing
2069 * @sshdr_external: Optional pointer to struct scsi_sense_hdr for
2070 * returning sense. Make sure that this is cleared before passing
2073 * Returns zero if unsuccessful or an error if TUR failed. For
2074 * removable media, UNIT_ATTENTION sets ->changed flag.
2077 scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2078 struct scsi_sense_hdr *sshdr_external)
2081 TEST_UNIT_READY, 0, 0, 0, 0, 0,
2083 struct scsi_sense_hdr *sshdr;
2086 if (!sshdr_external)
2087 sshdr = kzalloc(sizeof(*sshdr), GFP_KERNEL);
2089 sshdr = sshdr_external;
2091 /* try to eat the UNIT_ATTENTION if there are enough retries */
2093 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
2094 timeout, retries, NULL);
2095 if (sdev->removable && scsi_sense_valid(sshdr) &&
2096 sshdr->sense_key == UNIT_ATTENTION)
2098 } while (scsi_sense_valid(sshdr) &&
2099 sshdr->sense_key == UNIT_ATTENTION && --retries);
2101 if (!sshdr_external)
2105 EXPORT_SYMBOL(scsi_test_unit_ready);
2108 * scsi_device_set_state - Take the given device through the device state model.
2109 * @sdev: scsi device to change the state of.
2110 * @state: state to change to.
2112 * Returns zero if unsuccessful or an error if the requested
2113 * transition is illegal.
2116 scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2118 enum scsi_device_state oldstate = sdev->sdev_state;
2120 if (state == oldstate)
2126 case SDEV_CREATED_BLOCK:
2137 case SDEV_TRANSPORT_OFFLINE:
2150 case SDEV_TRANSPORT_OFFLINE:
2158 case SDEV_TRANSPORT_OFFLINE:
2173 case SDEV_CREATED_BLOCK:
2180 case SDEV_CREATED_BLOCK:
2195 case SDEV_TRANSPORT_OFFLINE:
2208 case SDEV_TRANSPORT_OFFLINE:
2210 case SDEV_CREATED_BLOCK:
2218 sdev->sdev_state = state;
2222 SCSI_LOG_ERROR_RECOVERY(1,
2223 sdev_printk(KERN_ERR, sdev,
2224 "Illegal state transition %s->%s\n",
2225 scsi_device_state_name(oldstate),
2226 scsi_device_state_name(state))
2230 EXPORT_SYMBOL(scsi_device_set_state);
2233 * sdev_evt_emit - emit a single SCSI device uevent
2234 * @sdev: associated SCSI device
2235 * @evt: event to emit
2237 * Send a single uevent (scsi_event) to the associated scsi_device.
2239 static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2244 switch (evt->evt_type) {
2245 case SDEV_EVT_MEDIA_CHANGE:
2246 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2248 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2249 envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2251 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2252 envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2254 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2255 envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2257 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2258 envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2260 case SDEV_EVT_LUN_CHANGE_REPORTED:
2261 envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2270 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2274 * sdev_evt_thread - send a uevent for each scsi event
2275 * @work: work struct for scsi_device
2277 * Dispatch queued events to their associated scsi_device kobjects
2280 void scsi_evt_thread(struct work_struct *work)
2282 struct scsi_device *sdev;
2283 enum scsi_device_event evt_type;
2284 LIST_HEAD(event_list);
2286 sdev = container_of(work, struct scsi_device, event_work);
2288 for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
2289 if (test_and_clear_bit(evt_type, sdev->pending_events))
2290 sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
2293 struct scsi_event *evt;
2294 struct list_head *this, *tmp;
2295 unsigned long flags;
2297 spin_lock_irqsave(&sdev->list_lock, flags);
2298 list_splice_init(&sdev->event_list, &event_list);
2299 spin_unlock_irqrestore(&sdev->list_lock, flags);
2301 if (list_empty(&event_list))
2304 list_for_each_safe(this, tmp, &event_list) {
2305 evt = list_entry(this, struct scsi_event, node);
2306 list_del(&evt->node);
2307 scsi_evt_emit(sdev, evt);
2314 * sdev_evt_send - send asserted event to uevent thread
2315 * @sdev: scsi_device event occurred on
2316 * @evt: event to send
2318 * Assert scsi device event asynchronously.
2320 void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2322 unsigned long flags;
2325 /* FIXME: currently this check eliminates all media change events
2326 * for polled devices. Need to update to discriminate between AN
2327 * and polled events */
2328 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2334 spin_lock_irqsave(&sdev->list_lock, flags);
2335 list_add_tail(&evt->node, &sdev->event_list);
2336 schedule_work(&sdev->event_work);
2337 spin_unlock_irqrestore(&sdev->list_lock, flags);
2339 EXPORT_SYMBOL_GPL(sdev_evt_send);
2342 * sdev_evt_alloc - allocate a new scsi event
2343 * @evt_type: type of event to allocate
2344 * @gfpflags: GFP flags for allocation
2346 * Allocates and returns a new scsi_event.
2348 struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2351 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2355 evt->evt_type = evt_type;
2356 INIT_LIST_HEAD(&evt->node);
2358 /* evt_type-specific initialization, if any */
2360 case SDEV_EVT_MEDIA_CHANGE:
2361 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2362 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2363 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2364 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2365 case SDEV_EVT_LUN_CHANGE_REPORTED:
2373 EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2376 * sdev_evt_send_simple - send asserted event to uevent thread
2377 * @sdev: scsi_device event occurred on
2378 * @evt_type: type of event to send
2379 * @gfpflags: GFP flags for allocation
2381 * Assert scsi device event asynchronously, given an event type.
2383 void sdev_evt_send_simple(struct scsi_device *sdev,
2384 enum scsi_device_event evt_type, gfp_t gfpflags)
2386 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2388 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2393 sdev_evt_send(sdev, evt);
2395 EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2398 * scsi_device_quiesce - Block user issued commands.
2399 * @sdev: scsi device to quiesce.
2401 * This works by trying to transition to the SDEV_QUIESCE state
2402 * (which must be a legal transition). When the device is in this
2403 * state, only special requests will be accepted, all others will
2404 * be deferred. Since special requests may also be requeued requests,
2405 * a successful return doesn't guarantee the device will be
2406 * totally quiescent.
2408 * Must be called with user context, may sleep.
2410 * Returns zero if unsuccessful or an error if not.
2413 scsi_device_quiesce(struct scsi_device *sdev)
2415 int err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2419 scsi_run_queue(sdev->request_queue);
2420 while (sdev->device_busy) {
2421 msleep_interruptible(200);
2422 scsi_run_queue(sdev->request_queue);
2426 EXPORT_SYMBOL(scsi_device_quiesce);
2429 * scsi_device_resume - Restart user issued commands to a quiesced device.
2430 * @sdev: scsi device to resume.
2432 * Moves the device from quiesced back to running and restarts the
2435 * Must be called with user context, may sleep.
2437 void scsi_device_resume(struct scsi_device *sdev)
2439 /* check if the device state was mutated prior to resume, and if
2440 * so assume the state is being managed elsewhere (for example
2441 * device deleted during suspend)
2443 if (sdev->sdev_state != SDEV_QUIESCE ||
2444 scsi_device_set_state(sdev, SDEV_RUNNING))
2446 scsi_run_queue(sdev->request_queue);
2448 EXPORT_SYMBOL(scsi_device_resume);
2451 device_quiesce_fn(struct scsi_device *sdev, void *data)
2453 scsi_device_quiesce(sdev);
2457 scsi_target_quiesce(struct scsi_target *starget)
2459 starget_for_each_device(starget, NULL, device_quiesce_fn);
2461 EXPORT_SYMBOL(scsi_target_quiesce);
2464 device_resume_fn(struct scsi_device *sdev, void *data)
2466 scsi_device_resume(sdev);
2470 scsi_target_resume(struct scsi_target *starget)
2472 starget_for_each_device(starget, NULL, device_resume_fn);
2474 EXPORT_SYMBOL(scsi_target_resume);
2477 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state
2478 * @sdev: device to block
2480 * Block request made by scsi lld's to temporarily stop all
2481 * scsi commands on the specified device. Called from interrupt
2482 * or normal process context.
2484 * Returns zero if successful or error if not
2487 * This routine transitions the device to the SDEV_BLOCK state
2488 * (which must be a legal transition). When the device is in this
2489 * state, all commands are deferred until the scsi lld reenables
2490 * the device with scsi_device_unblock or device_block_tmo fires.
2493 scsi_internal_device_block(struct scsi_device *sdev)
2495 struct request_queue *q = sdev->request_queue;
2496 unsigned long flags;
2499 err = scsi_device_set_state(sdev, SDEV_BLOCK);
2501 err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2508 * The device has transitioned to SDEV_BLOCK. Stop the
2509 * block layer from calling the midlayer with this device's
2512 spin_lock_irqsave(q->queue_lock, flags);
2514 spin_unlock_irqrestore(q->queue_lock, flags);
2518 EXPORT_SYMBOL_GPL(scsi_internal_device_block);
2521 * scsi_internal_device_unblock - resume a device after a block request
2522 * @sdev: device to resume
2523 * @new_state: state to set devices to after unblocking
2525 * Called by scsi lld's or the midlayer to restart the device queue
2526 * for the previously suspended scsi device. Called from interrupt or
2527 * normal process context.
2529 * Returns zero if successful or error if not.
2532 * This routine transitions the device to the SDEV_RUNNING state
2533 * or to one of the offline states (which must be a legal transition)
2534 * allowing the midlayer to goose the queue for this device.
2537 scsi_internal_device_unblock(struct scsi_device *sdev,
2538 enum scsi_device_state new_state)
2540 struct request_queue *q = sdev->request_queue;
2541 unsigned long flags;
2544 * Try to transition the scsi device to SDEV_RUNNING or one of the
2545 * offlined states and goose the device queue if successful.
2547 if ((sdev->sdev_state == SDEV_BLOCK) ||
2548 (sdev->sdev_state == SDEV_TRANSPORT_OFFLINE))
2549 sdev->sdev_state = new_state;
2550 else if (sdev->sdev_state == SDEV_CREATED_BLOCK) {
2551 if (new_state == SDEV_TRANSPORT_OFFLINE ||
2552 new_state == SDEV_OFFLINE)
2553 sdev->sdev_state = new_state;
2555 sdev->sdev_state = SDEV_CREATED;
2556 } else if (sdev->sdev_state != SDEV_CANCEL &&
2557 sdev->sdev_state != SDEV_OFFLINE)
2560 spin_lock_irqsave(q->queue_lock, flags);
2562 spin_unlock_irqrestore(q->queue_lock, flags);
2566 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock);
2569 device_block(struct scsi_device *sdev, void *data)
2571 scsi_internal_device_block(sdev);
2575 target_block(struct device *dev, void *data)
2577 if (scsi_is_target_device(dev))
2578 starget_for_each_device(to_scsi_target(dev), NULL,
2584 scsi_target_block(struct device *dev)
2586 if (scsi_is_target_device(dev))
2587 starget_for_each_device(to_scsi_target(dev), NULL,
2590 device_for_each_child(dev, NULL, target_block);
2592 EXPORT_SYMBOL_GPL(scsi_target_block);
2595 device_unblock(struct scsi_device *sdev, void *data)
2597 scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
2601 target_unblock(struct device *dev, void *data)
2603 if (scsi_is_target_device(dev))
2604 starget_for_each_device(to_scsi_target(dev), data,
2610 scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
2612 if (scsi_is_target_device(dev))
2613 starget_for_each_device(to_scsi_target(dev), &new_state,
2616 device_for_each_child(dev, &new_state, target_unblock);
2618 EXPORT_SYMBOL_GPL(scsi_target_unblock);
2621 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
2622 * @sgl: scatter-gather list
2623 * @sg_count: number of segments in sg
2624 * @offset: offset in bytes into sg, on return offset into the mapped area
2625 * @len: bytes to map, on return number of bytes mapped
2627 * Returns virtual address of the start of the mapped page
2629 void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
2630 size_t *offset, size_t *len)
2633 size_t sg_len = 0, len_complete = 0;
2634 struct scatterlist *sg;
2637 WARN_ON(!irqs_disabled());
2639 for_each_sg(sgl, sg, sg_count, i) {
2640 len_complete = sg_len; /* Complete sg-entries */
2641 sg_len += sg->length;
2642 if (sg_len > *offset)
2646 if (unlikely(i == sg_count)) {
2647 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
2649 __func__, sg_len, *offset, sg_count);
2654 /* Offset starting from the beginning of first page in this sg-entry */
2655 *offset = *offset - len_complete + sg->offset;
2657 /* Assumption: contiguous pages can be accessed as "page + i" */
2658 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
2659 *offset &= ~PAGE_MASK;
2661 /* Bytes in this sg-entry from *offset to the end of the page */
2662 sg_len = PAGE_SIZE - *offset;
2666 return kmap_atomic(page);
2668 EXPORT_SYMBOL(scsi_kmap_atomic_sg);
2671 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
2672 * @virt: virtual address to be unmapped
2674 void scsi_kunmap_atomic_sg(void *virt)
2676 kunmap_atomic(virt);
2678 EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
2680 void sdev_disable_disk_events(struct scsi_device *sdev)
2682 atomic_inc(&sdev->disk_events_disable_depth);
2684 EXPORT_SYMBOL(sdev_disable_disk_events);
2686 void sdev_enable_disk_events(struct scsi_device *sdev)
2688 if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0))
2690 atomic_dec(&sdev->disk_events_disable_depth);
2692 EXPORT_SYMBOL(sdev_enable_disk_events);