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 * __scsi_queue_insert - private queue insertion
80 * @cmd: The SCSI command being requeued
81 * @reason: The reason for the requeue
82 * @unbusy: Whether the queue should be unbusied
84 * This is a private queue insertion. The public interface
85 * scsi_queue_insert() always assumes the queue should be unbusied
86 * because it's always called before the completion. This function is
87 * for a requeue after completion, which should only occur in this
90 static void __scsi_queue_insert(struct scsi_cmnd
*cmd
, int reason
, int unbusy
)
92 struct Scsi_Host
*host
= cmd
->device
->host
;
93 struct scsi_device
*device
= cmd
->device
;
94 struct scsi_target
*starget
= scsi_target(device
);
95 struct request_queue
*q
= device
->request_queue
;
99 printk("Inserting command %p into mlqueue\n", cmd
));
102 * Set the appropriate busy bit for the device/host.
104 * If the host/device isn't busy, assume that something actually
105 * completed, and that we should be able to queue a command now.
107 * Note that the prior mid-layer assumption that any host could
108 * always queue at least one command is now broken. The mid-layer
109 * will implement a user specifiable stall (see
110 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
111 * if a command is requeued with no other commands outstanding
112 * either for the device or for the host.
115 case SCSI_MLQUEUE_HOST_BUSY
:
116 host
->host_blocked
= host
->max_host_blocked
;
118 case SCSI_MLQUEUE_DEVICE_BUSY
:
119 case SCSI_MLQUEUE_EH_RETRY
:
120 device
->device_blocked
= device
->max_device_blocked
;
122 case SCSI_MLQUEUE_TARGET_BUSY
:
123 starget
->target_blocked
= starget
->max_target_blocked
;
128 * Decrement the counters, since these commands are no longer
129 * active on the host/device.
132 scsi_device_unbusy(device
);
135 * Requeue this command. It will go before all other commands
136 * that are already in the queue. Schedule requeue work under
137 * lock such that the kblockd_schedule_work() call happens
138 * before blk_cleanup_queue() finishes.
141 spin_lock_irqsave(q
->queue_lock
, flags
);
142 blk_requeue_request(q
, cmd
->request
);
143 kblockd_schedule_work(&device
->requeue_work
);
144 spin_unlock_irqrestore(q
->queue_lock
, flags
);
148 * Function: scsi_queue_insert()
150 * Purpose: Insert a command in the midlevel queue.
152 * Arguments: cmd - command that we are adding to queue.
153 * reason - why we are inserting command to queue.
155 * Lock status: Assumed that lock is not held upon entry.
159 * Notes: We do this for one of two cases. Either the host is busy
160 * and it cannot accept any more commands for the time being,
161 * or the device returned QUEUE_FULL and can accept no more
163 * Notes: This could be called either from an interrupt context or a
164 * normal process context.
166 void scsi_queue_insert(struct scsi_cmnd
*cmd
, int reason
)
168 __scsi_queue_insert(cmd
, reason
, 1);
171 * scsi_execute - insert request and wait for the result
174 * @data_direction: data direction
175 * @buffer: data buffer
176 * @bufflen: len of buffer
177 * @sense: optional sense buffer
178 * @timeout: request timeout in seconds
179 * @retries: number of times to retry request
180 * @flags: or into request flags;
181 * @resid: optional residual length
183 * returns the req->errors value which is the scsi_cmnd result
186 int scsi_execute(struct scsi_device
*sdev
, const unsigned char *cmd
,
187 int data_direction
, void *buffer
, unsigned bufflen
,
188 unsigned char *sense
, int timeout
, int retries
, u64 flags
,
192 int write
= (data_direction
== DMA_TO_DEVICE
);
193 int ret
= DRIVER_ERROR
<< 24;
195 req
= blk_get_request(sdev
->request_queue
, write
, __GFP_WAIT
);
198 blk_rq_set_block_pc(req
);
200 if (bufflen
&& blk_rq_map_kern(sdev
->request_queue
, req
,
201 buffer
, bufflen
, __GFP_WAIT
))
204 req
->cmd_len
= COMMAND_SIZE(cmd
[0]);
205 memcpy(req
->cmd
, cmd
, req
->cmd_len
);
208 req
->retries
= retries
;
209 req
->timeout
= timeout
;
210 req
->cmd_flags
|= flags
| REQ_QUIET
| REQ_PREEMPT
;
213 * head injection *required* here otherwise quiesce won't work
215 blk_execute_rq(req
->q
, NULL
, req
, 1);
218 * Some devices (USB mass-storage in particular) may transfer
219 * garbage data together with a residue indicating that the data
220 * is invalid. Prevent the garbage from being misinterpreted
221 * and prevent security leaks by zeroing out the excess data.
223 if (unlikely(req
->resid_len
> 0 && req
->resid_len
<= bufflen
))
224 memset(buffer
+ (bufflen
- req
->resid_len
), 0, req
->resid_len
);
227 *resid
= req
->resid_len
;
230 blk_put_request(req
);
234 EXPORT_SYMBOL(scsi_execute
);
236 int scsi_execute_req_flags(struct scsi_device
*sdev
, const unsigned char *cmd
,
237 int data_direction
, void *buffer
, unsigned bufflen
,
238 struct scsi_sense_hdr
*sshdr
, int timeout
, int retries
,
239 int *resid
, u64 flags
)
245 sense
= kzalloc(SCSI_SENSE_BUFFERSIZE
, GFP_NOIO
);
247 return DRIVER_ERROR
<< 24;
249 result
= scsi_execute(sdev
, cmd
, data_direction
, buffer
, bufflen
,
250 sense
, timeout
, retries
, flags
, resid
);
252 scsi_normalize_sense(sense
, SCSI_SENSE_BUFFERSIZE
, sshdr
);
257 EXPORT_SYMBOL(scsi_execute_req_flags
);
260 * Function: scsi_init_cmd_errh()
262 * Purpose: Initialize cmd fields related to error handling.
264 * Arguments: cmd - command that is ready to be queued.
266 * Notes: This function has the job of initializing a number of
267 * fields related to error handling. Typically this will
268 * be called once for each command, as required.
270 static void scsi_init_cmd_errh(struct scsi_cmnd
*cmd
)
272 cmd
->serial_number
= 0;
273 scsi_set_resid(cmd
, 0);
274 memset(cmd
->sense_buffer
, 0, SCSI_SENSE_BUFFERSIZE
);
275 if (cmd
->cmd_len
== 0)
276 cmd
->cmd_len
= scsi_command_size(cmd
->cmnd
);
279 void scsi_device_unbusy(struct scsi_device
*sdev
)
281 struct Scsi_Host
*shost
= sdev
->host
;
282 struct scsi_target
*starget
= scsi_target(sdev
);
285 spin_lock_irqsave(shost
->host_lock
, flags
);
287 starget
->target_busy
--;
288 if (unlikely(scsi_host_in_recovery(shost
) &&
289 (shost
->host_failed
|| shost
->host_eh_scheduled
)))
290 scsi_eh_wakeup(shost
);
291 spin_unlock(shost
->host_lock
);
292 spin_lock(sdev
->request_queue
->queue_lock
);
294 spin_unlock_irqrestore(sdev
->request_queue
->queue_lock
, flags
);
298 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
299 * and call blk_run_queue for all the scsi_devices on the target -
300 * including current_sdev first.
302 * Called with *no* scsi locks held.
304 static void scsi_single_lun_run(struct scsi_device
*current_sdev
)
306 struct Scsi_Host
*shost
= current_sdev
->host
;
307 struct scsi_device
*sdev
, *tmp
;
308 struct scsi_target
*starget
= scsi_target(current_sdev
);
311 spin_lock_irqsave(shost
->host_lock
, flags
);
312 starget
->starget_sdev_user
= NULL
;
313 spin_unlock_irqrestore(shost
->host_lock
, flags
);
316 * Call blk_run_queue for all LUNs on the target, starting with
317 * current_sdev. We race with others (to set starget_sdev_user),
318 * but in most cases, we will be first. Ideally, each LU on the
319 * target would get some limited time or requests on the target.
321 blk_run_queue(current_sdev
->request_queue
);
323 spin_lock_irqsave(shost
->host_lock
, flags
);
324 if (starget
->starget_sdev_user
)
326 list_for_each_entry_safe(sdev
, tmp
, &starget
->devices
,
327 same_target_siblings
) {
328 if (sdev
== current_sdev
)
330 if (scsi_device_get(sdev
))
333 spin_unlock_irqrestore(shost
->host_lock
, flags
);
334 blk_run_queue(sdev
->request_queue
);
335 spin_lock_irqsave(shost
->host_lock
, flags
);
337 scsi_device_put(sdev
);
340 spin_unlock_irqrestore(shost
->host_lock
, flags
);
343 static inline int scsi_device_is_busy(struct scsi_device
*sdev
)
345 if (sdev
->device_busy
>= sdev
->queue_depth
|| sdev
->device_blocked
)
351 static inline int scsi_target_is_busy(struct scsi_target
*starget
)
353 return ((starget
->can_queue
> 0 &&
354 starget
->target_busy
>= starget
->can_queue
) ||
355 starget
->target_blocked
);
358 static inline int scsi_host_is_busy(struct Scsi_Host
*shost
)
360 if ((shost
->can_queue
> 0 && shost
->host_busy
>= shost
->can_queue
) ||
361 shost
->host_blocked
|| shost
->host_self_blocked
)
367 static void scsi_starved_list_run(struct Scsi_Host
*shost
)
369 LIST_HEAD(starved_list
);
370 struct scsi_device
*sdev
;
373 spin_lock_irqsave(shost
->host_lock
, flags
);
374 list_splice_init(&shost
->starved_list
, &starved_list
);
376 while (!list_empty(&starved_list
)) {
377 struct request_queue
*slq
;
380 * As long as shost is accepting commands and we have
381 * starved queues, call blk_run_queue. scsi_request_fn
382 * drops the queue_lock and can add us back to the
385 * host_lock protects the starved_list and starved_entry.
386 * scsi_request_fn must get the host_lock before checking
387 * or modifying starved_list or starved_entry.
389 if (scsi_host_is_busy(shost
))
392 sdev
= list_entry(starved_list
.next
,
393 struct scsi_device
, starved_entry
);
394 list_del_init(&sdev
->starved_entry
);
395 if (scsi_target_is_busy(scsi_target(sdev
))) {
396 list_move_tail(&sdev
->starved_entry
,
397 &shost
->starved_list
);
402 * Once we drop the host lock, a racing scsi_remove_device()
403 * call may remove the sdev from the starved list and destroy
404 * it and the queue. Mitigate by taking a reference to the
405 * queue and never touching the sdev again after we drop the
406 * host lock. Note: if __scsi_remove_device() invokes
407 * blk_cleanup_queue() before the queue is run from this
408 * function then blk_run_queue() will return immediately since
409 * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING.
411 slq
= sdev
->request_queue
;
412 if (!blk_get_queue(slq
))
414 spin_unlock_irqrestore(shost
->host_lock
, flags
);
419 spin_lock_irqsave(shost
->host_lock
, flags
);
421 /* put any unprocessed entries back */
422 list_splice(&starved_list
, &shost
->starved_list
);
423 spin_unlock_irqrestore(shost
->host_lock
, flags
);
427 * Function: scsi_run_queue()
429 * Purpose: Select a proper request queue to serve next
431 * Arguments: q - last request's queue
435 * Notes: The previous command was completely finished, start
436 * a new one if possible.
438 static void scsi_run_queue(struct request_queue
*q
)
440 struct scsi_device
*sdev
= q
->queuedata
;
442 if (scsi_target(sdev
)->single_lun
)
443 scsi_single_lun_run(sdev
);
444 if (!list_empty(&sdev
->host
->starved_list
))
445 scsi_starved_list_run(sdev
->host
);
450 void scsi_requeue_run_queue(struct work_struct
*work
)
452 struct scsi_device
*sdev
;
453 struct request_queue
*q
;
455 sdev
= container_of(work
, struct scsi_device
, requeue_work
);
456 q
= sdev
->request_queue
;
461 * Function: scsi_requeue_command()
463 * Purpose: Handle post-processing of completed commands.
465 * Arguments: q - queue to operate on
466 * cmd - command that may need to be requeued.
470 * Notes: After command completion, there may be blocks left
471 * over which weren't finished by the previous command
472 * this can be for a number of reasons - the main one is
473 * I/O errors in the middle of the request, in which case
474 * we need to request the blocks that come after the bad
476 * Notes: Upon return, cmd is a stale pointer.
478 static void scsi_requeue_command(struct request_queue
*q
, struct scsi_cmnd
*cmd
)
480 struct scsi_device
*sdev
= cmd
->device
;
481 struct request
*req
= cmd
->request
;
484 spin_lock_irqsave(q
->queue_lock
, flags
);
485 blk_unprep_request(req
);
487 scsi_put_command(cmd
);
488 blk_requeue_request(q
, req
);
489 spin_unlock_irqrestore(q
->queue_lock
, flags
);
493 put_device(&sdev
->sdev_gendev
);
496 void scsi_next_command(struct scsi_cmnd
*cmd
)
498 struct scsi_device
*sdev
= cmd
->device
;
499 struct request_queue
*q
= sdev
->request_queue
;
501 scsi_put_command(cmd
);
504 put_device(&sdev
->sdev_gendev
);
507 void scsi_run_host_queues(struct Scsi_Host
*shost
)
509 struct scsi_device
*sdev
;
511 shost_for_each_device(sdev
, shost
)
512 scsi_run_queue(sdev
->request_queue
);
515 static inline unsigned int scsi_sgtable_index(unsigned short nents
)
519 BUG_ON(nents
> SCSI_MAX_SG_SEGMENTS
);
524 index
= get_count_order(nents
) - 3;
529 static void scsi_sg_free(struct scatterlist
*sgl
, unsigned int nents
)
531 struct scsi_host_sg_pool
*sgp
;
533 sgp
= scsi_sg_pools
+ scsi_sgtable_index(nents
);
534 mempool_free(sgl
, sgp
->pool
);
537 static struct scatterlist
*scsi_sg_alloc(unsigned int nents
, gfp_t gfp_mask
)
539 struct scsi_host_sg_pool
*sgp
;
541 sgp
= scsi_sg_pools
+ scsi_sgtable_index(nents
);
542 return mempool_alloc(sgp
->pool
, gfp_mask
);
545 static int scsi_alloc_sgtable(struct scsi_data_buffer
*sdb
, int nents
,
552 ret
= __sg_alloc_table(&sdb
->table
, nents
, SCSI_MAX_SG_SEGMENTS
,
553 gfp_mask
, scsi_sg_alloc
);
555 __sg_free_table(&sdb
->table
, SCSI_MAX_SG_SEGMENTS
,
561 static void scsi_free_sgtable(struct scsi_data_buffer
*sdb
)
563 __sg_free_table(&sdb
->table
, SCSI_MAX_SG_SEGMENTS
, scsi_sg_free
);
567 * Function: scsi_release_buffers()
569 * Purpose: Free resources allocate for a scsi_command.
571 * Arguments: cmd - command that we are bailing.
573 * Lock status: Assumed that no lock is held upon entry.
577 * Notes: In the event that an upper level driver rejects a
578 * command, we must release resources allocated during
579 * the __init_io() function. Primarily this would involve
580 * the scatter-gather table.
582 void scsi_release_buffers(struct scsi_cmnd
*cmd
)
584 if (cmd
->sdb
.table
.nents
)
585 scsi_free_sgtable(&cmd
->sdb
);
587 memset(&cmd
->sdb
, 0, sizeof(cmd
->sdb
));
589 if (scsi_prot_sg_count(cmd
))
590 scsi_free_sgtable(cmd
->prot_sdb
);
592 EXPORT_SYMBOL(scsi_release_buffers
);
594 static void scsi_release_bidi_buffers(struct scsi_cmnd
*cmd
)
596 struct scsi_data_buffer
*bidi_sdb
= cmd
->request
->next_rq
->special
;
598 scsi_free_sgtable(bidi_sdb
);
599 kmem_cache_free(scsi_sdb_cache
, bidi_sdb
);
600 cmd
->request
->next_rq
->special
= NULL
;
604 * __scsi_error_from_host_byte - translate SCSI error code into errno
605 * @cmd: SCSI command (unused)
606 * @result: scsi error code
608 * Translate SCSI error code into standard UNIX errno.
610 * -ENOLINK temporary transport failure
611 * -EREMOTEIO permanent target failure, do not retry
612 * -EBADE permanent nexus failure, retry on other path
613 * -ENOSPC No write space available
614 * -ENODATA Medium error
615 * -EIO unspecified I/O error
617 static int __scsi_error_from_host_byte(struct scsi_cmnd
*cmd
, int result
)
621 switch(host_byte(result
)) {
622 case DID_TRANSPORT_FAILFAST
:
625 case DID_TARGET_FAILURE
:
626 set_host_byte(cmd
, DID_OK
);
629 case DID_NEXUS_FAILURE
:
630 set_host_byte(cmd
, DID_OK
);
633 case DID_ALLOC_FAILURE
:
634 set_host_byte(cmd
, DID_OK
);
637 case DID_MEDIUM_ERROR
:
638 set_host_byte(cmd
, DID_OK
);
650 * Function: scsi_io_completion()
652 * Purpose: Completion processing for block device I/O requests.
654 * Arguments: cmd - command that is finished.
656 * Lock status: Assumed that no lock is held upon entry.
660 * Notes: We will finish off the specified number of sectors. If we
661 * are done, the command block will be released and the queue
662 * function will be goosed. If we are not done then we have to
663 * figure out what to do next:
665 * a) We can call scsi_requeue_command(). The request
666 * will be unprepared and put back on the queue. Then
667 * a new command will be created for it. This should
668 * be used if we made forward progress, or if we want
669 * to switch from READ(10) to READ(6) for example.
671 * b) We can call __scsi_queue_insert(). The request will
672 * be put back on the queue and retried using the same
673 * command as before, possibly after a delay.
675 * c) We can call blk_end_request() with -EIO to fail
676 * the remainder of the request.
678 void scsi_io_completion(struct scsi_cmnd
*cmd
, unsigned int good_bytes
)
680 int result
= cmd
->result
;
681 struct request_queue
*q
= cmd
->device
->request_queue
;
682 struct request
*req
= cmd
->request
;
684 struct scsi_sense_hdr sshdr
;
686 int sense_deferred
= 0;
687 enum {ACTION_FAIL
, ACTION_REPREP
, ACTION_RETRY
,
688 ACTION_DELAYED_RETRY
} action
;
689 char *description
= NULL
;
690 unsigned long wait_for
= (cmd
->allowed
+ 1) * req
->timeout
;
693 sense_valid
= scsi_command_normalize_sense(cmd
, &sshdr
);
695 sense_deferred
= scsi_sense_is_deferred(&sshdr
);
698 if (req
->cmd_type
== REQ_TYPE_BLOCK_PC
) { /* SG_IO ioctl from block level */
700 if (sense_valid
&& req
->sense
) {
702 * SG_IO wants current and deferred errors
704 int len
= 8 + cmd
->sense_buffer
[7];
706 if (len
> SCSI_SENSE_BUFFERSIZE
)
707 len
= SCSI_SENSE_BUFFERSIZE
;
708 memcpy(req
->sense
, cmd
->sense_buffer
, len
);
709 req
->sense_len
= len
;
712 error
= __scsi_error_from_host_byte(cmd
, result
);
715 * __scsi_error_from_host_byte may have reset the host_byte
717 req
->errors
= cmd
->result
;
719 req
->resid_len
= scsi_get_resid(cmd
);
721 if (scsi_bidi_cmnd(cmd
)) {
723 * Bidi commands Must be complete as a whole,
724 * both sides at once.
726 req
->next_rq
->resid_len
= scsi_in(cmd
)->resid
;
728 scsi_release_buffers(cmd
);
729 scsi_release_bidi_buffers(cmd
);
731 blk_end_request_all(req
, 0);
733 scsi_next_command(cmd
);
738 /* no bidi support for !REQ_TYPE_BLOCK_PC yet */
739 BUG_ON(blk_bidi_rq(req
));
742 * Next deal with any sectors which we were able to correctly
745 SCSI_LOG_HLCOMPLETE(1, printk("%u sectors total, "
747 blk_rq_sectors(req
), good_bytes
));
750 * Recovered errors need reporting, but they're always treated
751 * as success, so fiddle the result code here. For BLOCK_PC
752 * we already took a copy of the original into rq->errors which
753 * is what gets returned to the user
755 if (sense_valid
&& (sshdr
.sense_key
== RECOVERED_ERROR
)) {
756 /* if ATA PASS-THROUGH INFORMATION AVAILABLE skip
757 * print since caller wants ATA registers. Only occurs on
758 * SCSI ATA PASS_THROUGH commands when CK_COND=1
760 if ((sshdr
.asc
== 0x0) && (sshdr
.ascq
== 0x1d))
762 else if (!(req
->cmd_flags
& REQ_QUIET
))
763 scsi_print_sense("", cmd
);
765 /* BLOCK_PC may have set error */
770 * If we finished all bytes in the request we are done now.
772 if (!blk_end_request(req
, error
, good_bytes
))
776 * Kill remainder if no retrys.
778 if (error
&& scsi_noretry_cmd(cmd
)) {
779 blk_end_request_all(req
, error
);
784 * If there had been no error, but we have leftover bytes in the
785 * requeues just queue the command up again.
790 error
= __scsi_error_from_host_byte(cmd
, result
);
792 if (host_byte(result
) == DID_RESET
) {
793 /* Third party bus reset or reset for error recovery
794 * reasons. Just retry the command and see what
797 action
= ACTION_RETRY
;
798 } else if (sense_valid
&& !sense_deferred
) {
799 switch (sshdr
.sense_key
) {
801 if (cmd
->device
->removable
) {
802 /* Detected disc change. Set a bit
803 * and quietly refuse further access.
805 cmd
->device
->changed
= 1;
806 description
= "Media Changed";
807 action
= ACTION_FAIL
;
809 /* Must have been a power glitch, or a
810 * bus reset. Could not have been a
811 * media change, so we just retry the
812 * command and see what happens.
814 action
= ACTION_RETRY
;
817 case ILLEGAL_REQUEST
:
818 /* If we had an ILLEGAL REQUEST returned, then
819 * we may have performed an unsupported
820 * command. The only thing this should be
821 * would be a ten byte read where only a six
822 * byte read was supported. Also, on a system
823 * where READ CAPACITY failed, we may have
824 * read past the end of the disk.
826 if ((cmd
->device
->use_10_for_rw
&&
827 sshdr
.asc
== 0x20 && sshdr
.ascq
== 0x00) &&
828 (cmd
->cmnd
[0] == READ_10
||
829 cmd
->cmnd
[0] == WRITE_10
)) {
830 /* This will issue a new 6-byte command. */
831 cmd
->device
->use_10_for_rw
= 0;
832 action
= ACTION_REPREP
;
833 } else if (sshdr
.asc
== 0x10) /* DIX */ {
834 description
= "Host Data Integrity Failure";
835 action
= ACTION_FAIL
;
837 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
838 } else if (sshdr
.asc
== 0x20 || sshdr
.asc
== 0x24) {
839 switch (cmd
->cmnd
[0]) {
841 description
= "Discard failure";
845 if (cmd
->cmnd
[1] & 0x8)
846 description
= "Discard failure";
849 "Write same failure";
852 description
= "Invalid command failure";
855 action
= ACTION_FAIL
;
858 action
= ACTION_FAIL
;
860 case ABORTED_COMMAND
:
861 action
= ACTION_FAIL
;
862 if (sshdr
.asc
== 0x10) { /* DIF */
863 description
= "Target Data Integrity Failure";
868 /* If the device is in the process of becoming
869 * ready, or has a temporary blockage, retry.
871 if (sshdr
.asc
== 0x04) {
872 switch (sshdr
.ascq
) {
873 case 0x01: /* becoming ready */
874 case 0x04: /* format in progress */
875 case 0x05: /* rebuild in progress */
876 case 0x06: /* recalculation in progress */
877 case 0x07: /* operation in progress */
878 case 0x08: /* Long write in progress */
879 case 0x09: /* self test in progress */
880 case 0x14: /* space allocation in progress */
881 action
= ACTION_DELAYED_RETRY
;
884 description
= "Device not ready";
885 action
= ACTION_FAIL
;
889 description
= "Device not ready";
890 action
= ACTION_FAIL
;
893 case VOLUME_OVERFLOW
:
894 /* See SSC3rXX or current. */
895 action
= ACTION_FAIL
;
898 description
= "Unhandled sense code";
899 action
= ACTION_FAIL
;
903 description
= "Unhandled error code";
904 action
= ACTION_FAIL
;
907 if (action
!= ACTION_FAIL
&&
908 time_before(cmd
->jiffies_at_alloc
+ wait_for
, jiffies
)) {
909 action
= ACTION_FAIL
;
910 description
= "Command timed out";
915 /* Give up and fail the remainder of the request */
916 if (!(req
->cmd_flags
& REQ_QUIET
)) {
918 scmd_printk(KERN_INFO
, cmd
, "%s\n",
920 scsi_print_result(cmd
);
921 if (driver_byte(result
) & DRIVER_SENSE
)
922 scsi_print_sense("", cmd
);
923 scsi_print_command(cmd
);
925 if (!blk_end_request_err(req
, error
))
930 /* Unprep the request and put it back at the head of the queue.
931 * A new command will be prepared and issued.
933 scsi_release_buffers(cmd
);
934 scsi_requeue_command(q
, cmd
);
937 /* Retry the same command immediately */
938 __scsi_queue_insert(cmd
, SCSI_MLQUEUE_EH_RETRY
, 0);
940 case ACTION_DELAYED_RETRY
:
941 /* Retry the same command after a delay */
942 __scsi_queue_insert(cmd
, SCSI_MLQUEUE_DEVICE_BUSY
, 0);
948 scsi_release_buffers(cmd
);
949 scsi_next_command(cmd
);
952 static int scsi_init_sgtable(struct request
*req
, struct scsi_data_buffer
*sdb
,
958 * If sg table allocation fails, requeue request later.
960 if (unlikely(scsi_alloc_sgtable(sdb
, req
->nr_phys_segments
,
962 return BLKPREP_DEFER
;
966 * Next, walk the list, and fill in the addresses and sizes of
969 count
= blk_rq_map_sg(req
->q
, req
, sdb
->table
.sgl
);
970 BUG_ON(count
> sdb
->table
.nents
);
971 sdb
->table
.nents
= count
;
972 sdb
->length
= blk_rq_bytes(req
);
977 * Function: scsi_init_io()
979 * Purpose: SCSI I/O initialize function.
981 * Arguments: cmd - Command descriptor we wish to initialize
983 * Returns: 0 on success
984 * BLKPREP_DEFER if the failure is retryable
985 * BLKPREP_KILL if the failure is fatal
987 int scsi_init_io(struct scsi_cmnd
*cmd
, gfp_t gfp_mask
)
989 struct scsi_device
*sdev
= cmd
->device
;
990 struct request
*rq
= cmd
->request
;
992 int error
= scsi_init_sgtable(rq
, &cmd
->sdb
, gfp_mask
);
996 if (blk_bidi_rq(rq
)) {
997 struct scsi_data_buffer
*bidi_sdb
= kmem_cache_zalloc(
998 scsi_sdb_cache
, GFP_ATOMIC
);
1000 error
= BLKPREP_DEFER
;
1004 rq
->next_rq
->special
= bidi_sdb
;
1005 error
= scsi_init_sgtable(rq
->next_rq
, bidi_sdb
, GFP_ATOMIC
);
1010 if (blk_integrity_rq(rq
)) {
1011 struct scsi_data_buffer
*prot_sdb
= cmd
->prot_sdb
;
1014 BUG_ON(prot_sdb
== NULL
);
1015 ivecs
= blk_rq_count_integrity_sg(rq
->q
, rq
->bio
);
1017 if (scsi_alloc_sgtable(prot_sdb
, ivecs
, gfp_mask
)) {
1018 error
= BLKPREP_DEFER
;
1022 count
= blk_rq_map_integrity_sg(rq
->q
, rq
->bio
,
1023 prot_sdb
->table
.sgl
);
1024 BUG_ON(unlikely(count
> ivecs
));
1025 BUG_ON(unlikely(count
> queue_max_integrity_segments(rq
->q
)));
1027 cmd
->prot_sdb
= prot_sdb
;
1028 cmd
->prot_sdb
->table
.nents
= count
;
1034 scsi_release_buffers(cmd
);
1035 cmd
->request
->special
= NULL
;
1036 scsi_put_command(cmd
);
1037 put_device(&sdev
->sdev_gendev
);
1040 EXPORT_SYMBOL(scsi_init_io
);
1042 static struct scsi_cmnd
*scsi_get_cmd_from_req(struct scsi_device
*sdev
,
1043 struct request
*req
)
1045 struct scsi_cmnd
*cmd
;
1047 if (!req
->special
) {
1048 /* Bail if we can't get a reference to the device */
1049 if (!get_device(&sdev
->sdev_gendev
))
1052 cmd
= scsi_get_command(sdev
, GFP_ATOMIC
);
1053 if (unlikely(!cmd
)) {
1054 put_device(&sdev
->sdev_gendev
);
1062 /* pull a tag out of the request if we have one */
1063 cmd
->tag
= req
->tag
;
1066 cmd
->cmnd
= req
->cmd
;
1067 cmd
->prot_op
= SCSI_PROT_NORMAL
;
1072 int scsi_setup_blk_pc_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1074 struct scsi_cmnd
*cmd
= req
->special
;
1077 * BLOCK_PC requests may transfer data, in which case they must
1078 * a bio attached to them. Or they might contain a SCSI command
1079 * that does not transfer data, in which case they may optionally
1080 * submit a request without an attached bio.
1085 BUG_ON(!req
->nr_phys_segments
);
1087 ret
= scsi_init_io(cmd
, GFP_ATOMIC
);
1091 BUG_ON(blk_rq_bytes(req
));
1093 memset(&cmd
->sdb
, 0, sizeof(cmd
->sdb
));
1096 cmd
->cmd_len
= req
->cmd_len
;
1097 if (!blk_rq_bytes(req
))
1098 cmd
->sc_data_direction
= DMA_NONE
;
1099 else if (rq_data_dir(req
) == WRITE
)
1100 cmd
->sc_data_direction
= DMA_TO_DEVICE
;
1102 cmd
->sc_data_direction
= DMA_FROM_DEVICE
;
1104 cmd
->transfersize
= blk_rq_bytes(req
);
1105 cmd
->allowed
= req
->retries
;
1108 EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd
);
1111 * Setup a REQ_TYPE_FS command. These are simple read/write request
1112 * from filesystems that still need to be translated to SCSI CDBs from
1115 int scsi_setup_fs_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1117 struct scsi_cmnd
*cmd
= req
->special
;
1119 if (unlikely(sdev
->scsi_dh_data
&& sdev
->scsi_dh_data
->scsi_dh
1120 && sdev
->scsi_dh_data
->scsi_dh
->prep_fn
)) {
1121 int ret
= sdev
->scsi_dh_data
->scsi_dh
->prep_fn(sdev
, req
);
1122 if (ret
!= BLKPREP_OK
)
1127 * Filesystem requests must transfer data.
1129 BUG_ON(!req
->nr_phys_segments
);
1131 memset(cmd
->cmnd
, 0, BLK_MAX_CDB
);
1132 return scsi_init_io(cmd
, GFP_ATOMIC
);
1134 EXPORT_SYMBOL(scsi_setup_fs_cmnd
);
1137 scsi_prep_state_check(struct scsi_device
*sdev
, struct request
*req
)
1139 int ret
= BLKPREP_OK
;
1142 * If the device is not in running state we will reject some
1145 if (unlikely(sdev
->sdev_state
!= SDEV_RUNNING
)) {
1146 switch (sdev
->sdev_state
) {
1148 case SDEV_TRANSPORT_OFFLINE
:
1150 * If the device is offline we refuse to process any
1151 * commands. The device must be brought online
1152 * before trying any recovery commands.
1154 sdev_printk(KERN_ERR
, sdev
,
1155 "rejecting I/O to offline device\n");
1160 * If the device is fully deleted, we refuse to
1161 * process any commands as well.
1163 sdev_printk(KERN_ERR
, sdev
,
1164 "rejecting I/O to dead device\n");
1169 case SDEV_CREATED_BLOCK
:
1171 * If the devices is blocked we defer normal commands.
1173 if (!(req
->cmd_flags
& REQ_PREEMPT
))
1174 ret
= BLKPREP_DEFER
;
1178 * For any other not fully online state we only allow
1179 * special commands. In particular any user initiated
1180 * command is not allowed.
1182 if (!(req
->cmd_flags
& REQ_PREEMPT
))
1191 scsi_prep_return(struct request_queue
*q
, struct request
*req
, int ret
)
1193 struct scsi_device
*sdev
= q
->queuedata
;
1197 req
->errors
= DID_NO_CONNECT
<< 16;
1198 /* release the command and kill it */
1200 struct scsi_cmnd
*cmd
= req
->special
;
1201 scsi_release_buffers(cmd
);
1202 scsi_put_command(cmd
);
1203 put_device(&sdev
->sdev_gendev
);
1204 req
->special
= NULL
;
1209 * If we defer, the blk_peek_request() returns NULL, but the
1210 * queue must be restarted, so we schedule a callback to happen
1213 if (sdev
->device_busy
== 0)
1214 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1217 req
->cmd_flags
|= REQ_DONTPREP
;
1223 static int scsi_prep_fn(struct request_queue
*q
, struct request
*req
)
1225 struct scsi_device
*sdev
= q
->queuedata
;
1226 struct scsi_cmnd
*cmd
;
1229 ret
= scsi_prep_state_check(sdev
, req
);
1230 if (ret
!= BLKPREP_OK
)
1233 cmd
= scsi_get_cmd_from_req(sdev
, req
);
1234 if (unlikely(!cmd
)) {
1235 ret
= BLKPREP_DEFER
;
1239 if (req
->cmd_type
== REQ_TYPE_FS
)
1240 ret
= scsi_cmd_to_driver(cmd
)->init_command(cmd
);
1241 else if (req
->cmd_type
== REQ_TYPE_BLOCK_PC
)
1242 ret
= scsi_setup_blk_pc_cmnd(sdev
, req
);
1247 return scsi_prep_return(q
, req
, ret
);
1250 static void scsi_unprep_fn(struct request_queue
*q
, struct request
*req
)
1252 if (req
->cmd_type
== REQ_TYPE_FS
) {
1253 struct scsi_cmnd
*cmd
= req
->special
;
1254 struct scsi_driver
*drv
= scsi_cmd_to_driver(cmd
);
1256 if (drv
->uninit_command
)
1257 drv
->uninit_command(cmd
);
1262 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1265 * Called with the queue_lock held.
1267 static inline int scsi_dev_queue_ready(struct request_queue
*q
,
1268 struct scsi_device
*sdev
)
1270 if (sdev
->device_busy
== 0 && sdev
->device_blocked
) {
1272 * unblock after device_blocked iterates to zero
1274 if (--sdev
->device_blocked
== 0) {
1276 sdev_printk(KERN_INFO
, sdev
,
1277 "unblocking device at zero depth\n"));
1279 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1283 if (scsi_device_is_busy(sdev
))
1291 * scsi_target_queue_ready: checks if there we can send commands to target
1292 * @sdev: scsi device on starget to check.
1294 * Called with the host lock held.
1296 static inline int scsi_target_queue_ready(struct Scsi_Host
*shost
,
1297 struct scsi_device
*sdev
)
1299 struct scsi_target
*starget
= scsi_target(sdev
);
1301 if (starget
->single_lun
) {
1302 if (starget
->starget_sdev_user
&&
1303 starget
->starget_sdev_user
!= sdev
)
1305 starget
->starget_sdev_user
= sdev
;
1308 if (starget
->target_busy
== 0 && starget
->target_blocked
) {
1310 * unblock after target_blocked iterates to zero
1312 if (--starget
->target_blocked
== 0) {
1313 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO
, starget
,
1314 "unblocking target at zero depth\n"));
1319 if (scsi_target_is_busy(starget
)) {
1320 list_move_tail(&sdev
->starved_entry
, &shost
->starved_list
);
1328 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1329 * return 0. We must end up running the queue again whenever 0 is
1330 * returned, else IO can hang.
1332 * Called with host_lock held.
1334 static inline int scsi_host_queue_ready(struct request_queue
*q
,
1335 struct Scsi_Host
*shost
,
1336 struct scsi_device
*sdev
)
1338 if (scsi_host_in_recovery(shost
))
1340 if (shost
->host_busy
== 0 && shost
->host_blocked
) {
1342 * unblock after host_blocked iterates to zero
1344 if (--shost
->host_blocked
== 0) {
1346 printk("scsi%d unblocking host at zero depth\n",
1352 if (scsi_host_is_busy(shost
)) {
1353 if (list_empty(&sdev
->starved_entry
))
1354 list_add_tail(&sdev
->starved_entry
, &shost
->starved_list
);
1358 /* We're OK to process the command, so we can't be starved */
1359 if (!list_empty(&sdev
->starved_entry
))
1360 list_del_init(&sdev
->starved_entry
);
1366 * Busy state exporting function for request stacking drivers.
1368 * For efficiency, no lock is taken to check the busy state of
1369 * shost/starget/sdev, since the returned value is not guaranteed and
1370 * may be changed after request stacking drivers call the function,
1371 * regardless of taking lock or not.
1373 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1374 * needs to return 'not busy'. Otherwise, request stacking drivers
1375 * may hold requests forever.
1377 static int scsi_lld_busy(struct request_queue
*q
)
1379 struct scsi_device
*sdev
= q
->queuedata
;
1380 struct Scsi_Host
*shost
;
1382 if (blk_queue_dying(q
))
1388 * Ignore host/starget busy state.
1389 * Since block layer does not have a concept of fairness across
1390 * multiple queues, congestion of host/starget needs to be handled
1393 if (scsi_host_in_recovery(shost
) || scsi_device_is_busy(sdev
))
1400 * Kill a request for a dead device
1402 static void scsi_kill_request(struct request
*req
, struct request_queue
*q
)
1404 struct scsi_cmnd
*cmd
= req
->special
;
1405 struct scsi_device
*sdev
;
1406 struct scsi_target
*starget
;
1407 struct Scsi_Host
*shost
;
1409 blk_start_request(req
);
1411 scmd_printk(KERN_INFO
, cmd
, "killing request\n");
1414 starget
= scsi_target(sdev
);
1416 scsi_init_cmd_errh(cmd
);
1417 cmd
->result
= DID_NO_CONNECT
<< 16;
1418 atomic_inc(&cmd
->device
->iorequest_cnt
);
1421 * SCSI request completion path will do scsi_device_unbusy(),
1422 * bump busy counts. To bump the counters, we need to dance
1423 * with the locks as normal issue path does.
1425 sdev
->device_busy
++;
1426 spin_unlock(sdev
->request_queue
->queue_lock
);
1427 spin_lock(shost
->host_lock
);
1429 starget
->target_busy
++;
1430 spin_unlock(shost
->host_lock
);
1431 spin_lock(sdev
->request_queue
->queue_lock
);
1433 blk_complete_request(req
);
1436 static void scsi_softirq_done(struct request
*rq
)
1438 struct scsi_cmnd
*cmd
= rq
->special
;
1439 unsigned long wait_for
= (cmd
->allowed
+ 1) * rq
->timeout
;
1442 INIT_LIST_HEAD(&cmd
->eh_entry
);
1444 atomic_inc(&cmd
->device
->iodone_cnt
);
1446 atomic_inc(&cmd
->device
->ioerr_cnt
);
1448 disposition
= scsi_decide_disposition(cmd
);
1449 if (disposition
!= SUCCESS
&&
1450 time_before(cmd
->jiffies_at_alloc
+ wait_for
, jiffies
)) {
1451 sdev_printk(KERN_ERR
, cmd
->device
,
1452 "timing out command, waited %lus\n",
1454 disposition
= SUCCESS
;
1457 scsi_log_completion(cmd
, disposition
);
1459 switch (disposition
) {
1461 scsi_finish_command(cmd
);
1464 scsi_queue_insert(cmd
, SCSI_MLQUEUE_EH_RETRY
);
1466 case ADD_TO_MLQUEUE
:
1467 scsi_queue_insert(cmd
, SCSI_MLQUEUE_DEVICE_BUSY
);
1470 if (!scsi_eh_scmd_add(cmd
, 0))
1471 scsi_finish_command(cmd
);
1476 * Function: scsi_request_fn()
1478 * Purpose: Main strategy routine for SCSI.
1480 * Arguments: q - Pointer to actual queue.
1484 * Lock status: IO request lock assumed to be held when called.
1486 static void scsi_request_fn(struct request_queue
*q
)
1487 __releases(q
->queue_lock
)
1488 __acquires(q
->queue_lock
)
1490 struct scsi_device
*sdev
= q
->queuedata
;
1491 struct Scsi_Host
*shost
;
1492 struct scsi_cmnd
*cmd
;
1493 struct request
*req
;
1496 * To start with, we keep looping until the queue is empty, or until
1497 * the host is no longer able to accept any more requests.
1503 * get next queueable request. We do this early to make sure
1504 * that the request is fully prepared even if we cannot
1507 req
= blk_peek_request(q
);
1508 if (!req
|| !scsi_dev_queue_ready(q
, sdev
))
1511 if (unlikely(!scsi_device_online(sdev
))) {
1512 sdev_printk(KERN_ERR
, sdev
,
1513 "rejecting I/O to offline device\n");
1514 scsi_kill_request(req
, q
);
1520 * Remove the request from the request list.
1522 if (!(blk_queue_tagged(q
) && !blk_queue_start_tag(q
, req
)))
1523 blk_start_request(req
);
1524 sdev
->device_busy
++;
1526 spin_unlock(q
->queue_lock
);
1528 if (unlikely(cmd
== NULL
)) {
1529 printk(KERN_CRIT
"impossible request in %s.\n"
1530 "please mail a stack trace to "
1531 "linux-scsi@vger.kernel.org\n",
1533 blk_dump_rq_flags(req
, "foo");
1536 spin_lock(shost
->host_lock
);
1539 * We hit this when the driver is using a host wide
1540 * tag map. For device level tag maps the queue_depth check
1541 * in the device ready fn would prevent us from trying
1542 * to allocate a tag. Since the map is a shared host resource
1543 * we add the dev to the starved list so it eventually gets
1544 * a run when a tag is freed.
1546 if (blk_queue_tagged(q
) && !blk_rq_tagged(req
)) {
1547 if (list_empty(&sdev
->starved_entry
))
1548 list_add_tail(&sdev
->starved_entry
,
1549 &shost
->starved_list
);
1553 if (!scsi_target_queue_ready(shost
, sdev
))
1556 if (!scsi_host_queue_ready(q
, shost
, sdev
))
1559 scsi_target(sdev
)->target_busy
++;
1563 * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will
1564 * take the lock again.
1566 spin_unlock_irq(shost
->host_lock
);
1569 * Finally, initialize any error handling parameters, and set up
1570 * the timers for timeouts.
1572 scsi_init_cmd_errh(cmd
);
1575 * Dispatch the command to the low-level driver.
1577 rtn
= scsi_dispatch_cmd(cmd
);
1578 spin_lock_irq(q
->queue_lock
);
1586 spin_unlock_irq(shost
->host_lock
);
1589 * lock q, handle tag, requeue req, and decrement device_busy. We
1590 * must return with queue_lock held.
1592 * Decrementing device_busy without checking it is OK, as all such
1593 * cases (host limits or settings) should run the queue at some
1596 spin_lock_irq(q
->queue_lock
);
1597 blk_requeue_request(q
, req
);
1598 sdev
->device_busy
--;
1600 if (sdev
->device_busy
== 0)
1601 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1604 u64
scsi_calculate_bounce_limit(struct Scsi_Host
*shost
)
1606 struct device
*host_dev
;
1607 u64 bounce_limit
= 0xffffffff;
1609 if (shost
->unchecked_isa_dma
)
1610 return BLK_BOUNCE_ISA
;
1612 * Platforms with virtual-DMA translation
1613 * hardware have no practical limit.
1615 if (!PCI_DMA_BUS_IS_PHYS
)
1616 return BLK_BOUNCE_ANY
;
1618 host_dev
= scsi_get_device(shost
);
1619 if (host_dev
&& host_dev
->dma_mask
)
1620 bounce_limit
= (u64
)dma_max_pfn(host_dev
) << PAGE_SHIFT
;
1622 return bounce_limit
;
1624 EXPORT_SYMBOL(scsi_calculate_bounce_limit
);
1626 struct request_queue
*__scsi_alloc_queue(struct Scsi_Host
*shost
,
1627 request_fn_proc
*request_fn
)
1629 struct request_queue
*q
;
1630 struct device
*dev
= shost
->dma_dev
;
1632 q
= blk_init_queue(request_fn
, NULL
);
1637 * this limit is imposed by hardware restrictions
1639 blk_queue_max_segments(q
, min_t(unsigned short, shost
->sg_tablesize
,
1640 SCSI_MAX_SG_CHAIN_SEGMENTS
));
1642 if (scsi_host_prot_dma(shost
)) {
1643 shost
->sg_prot_tablesize
=
1644 min_not_zero(shost
->sg_prot_tablesize
,
1645 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS
);
1646 BUG_ON(shost
->sg_prot_tablesize
< shost
->sg_tablesize
);
1647 blk_queue_max_integrity_segments(q
, shost
->sg_prot_tablesize
);
1650 blk_queue_max_hw_sectors(q
, shost
->max_sectors
);
1651 blk_queue_bounce_limit(q
, scsi_calculate_bounce_limit(shost
));
1652 blk_queue_segment_boundary(q
, shost
->dma_boundary
);
1653 dma_set_seg_boundary(dev
, shost
->dma_boundary
);
1655 blk_queue_max_segment_size(q
, dma_get_max_seg_size(dev
));
1657 if (!shost
->use_clustering
)
1658 q
->limits
.cluster
= 0;
1661 * set a reasonable default alignment on word boundaries: the
1662 * host and device may alter it using
1663 * blk_queue_update_dma_alignment() later.
1665 blk_queue_dma_alignment(q
, 0x03);
1669 EXPORT_SYMBOL(__scsi_alloc_queue
);
1671 struct request_queue
*scsi_alloc_queue(struct scsi_device
*sdev
)
1673 struct request_queue
*q
;
1675 q
= __scsi_alloc_queue(sdev
->host
, scsi_request_fn
);
1679 blk_queue_prep_rq(q
, scsi_prep_fn
);
1680 blk_queue_unprep_rq(q
, scsi_unprep_fn
);
1681 blk_queue_softirq_done(q
, scsi_softirq_done
);
1682 blk_queue_rq_timed_out(q
, scsi_times_out
);
1683 blk_queue_lld_busy(q
, scsi_lld_busy
);
1688 * Function: scsi_block_requests()
1690 * Purpose: Utility function used by low-level drivers to prevent further
1691 * commands from being queued to the device.
1693 * Arguments: shost - Host in question
1697 * Lock status: No locks are assumed held.
1699 * Notes: There is no timer nor any other means by which the requests
1700 * get unblocked other than the low-level driver calling
1701 * scsi_unblock_requests().
1703 void scsi_block_requests(struct Scsi_Host
*shost
)
1705 shost
->host_self_blocked
= 1;
1707 EXPORT_SYMBOL(scsi_block_requests
);
1710 * Function: scsi_unblock_requests()
1712 * Purpose: Utility function used by low-level drivers to allow further
1713 * commands from being queued to the device.
1715 * Arguments: shost - Host in question
1719 * Lock status: No locks are assumed held.
1721 * Notes: There is no timer nor any other means by which the requests
1722 * get unblocked other than the low-level driver calling
1723 * scsi_unblock_requests().
1725 * This is done as an API function so that changes to the
1726 * internals of the scsi mid-layer won't require wholesale
1727 * changes to drivers that use this feature.
1729 void scsi_unblock_requests(struct Scsi_Host
*shost
)
1731 shost
->host_self_blocked
= 0;
1732 scsi_run_host_queues(shost
);
1734 EXPORT_SYMBOL(scsi_unblock_requests
);
1736 int __init
scsi_init_queue(void)
1740 scsi_sdb_cache
= kmem_cache_create("scsi_data_buffer",
1741 sizeof(struct scsi_data_buffer
),
1743 if (!scsi_sdb_cache
) {
1744 printk(KERN_ERR
"SCSI: can't init scsi sdb cache\n");
1748 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
1749 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
1750 int size
= sgp
->size
* sizeof(struct scatterlist
);
1752 sgp
->slab
= kmem_cache_create(sgp
->name
, size
, 0,
1753 SLAB_HWCACHE_ALIGN
, NULL
);
1755 printk(KERN_ERR
"SCSI: can't init sg slab %s\n",
1760 sgp
->pool
= mempool_create_slab_pool(SG_MEMPOOL_SIZE
,
1763 printk(KERN_ERR
"SCSI: can't init sg mempool %s\n",
1772 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
1773 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
1775 mempool_destroy(sgp
->pool
);
1777 kmem_cache_destroy(sgp
->slab
);
1779 kmem_cache_destroy(scsi_sdb_cache
);
1784 void scsi_exit_queue(void)
1788 kmem_cache_destroy(scsi_sdb_cache
);
1790 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
1791 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
1792 mempool_destroy(sgp
->pool
);
1793 kmem_cache_destroy(sgp
->slab
);
1798 * scsi_mode_select - issue a mode select
1799 * @sdev: SCSI device to be queried
1800 * @pf: Page format bit (1 == standard, 0 == vendor specific)
1801 * @sp: Save page bit (0 == don't save, 1 == save)
1802 * @modepage: mode page being requested
1803 * @buffer: request buffer (may not be smaller than eight bytes)
1804 * @len: length of request buffer.
1805 * @timeout: command timeout
1806 * @retries: number of retries before failing
1807 * @data: returns a structure abstracting the mode header data
1808 * @sshdr: place to put sense data (or NULL if no sense to be collected).
1809 * must be SCSI_SENSE_BUFFERSIZE big.
1811 * Returns zero if successful; negative error number or scsi
1816 scsi_mode_select(struct scsi_device
*sdev
, int pf
, int sp
, int modepage
,
1817 unsigned char *buffer
, int len
, int timeout
, int retries
,
1818 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
1820 unsigned char cmd
[10];
1821 unsigned char *real_buffer
;
1824 memset(cmd
, 0, sizeof(cmd
));
1825 cmd
[1] = (pf
? 0x10 : 0) | (sp
? 0x01 : 0);
1827 if (sdev
->use_10_for_ms
) {
1830 real_buffer
= kmalloc(8 + len
, GFP_KERNEL
);
1833 memcpy(real_buffer
+ 8, buffer
, len
);
1837 real_buffer
[2] = data
->medium_type
;
1838 real_buffer
[3] = data
->device_specific
;
1839 real_buffer
[4] = data
->longlba
? 0x01 : 0;
1841 real_buffer
[6] = data
->block_descriptor_length
>> 8;
1842 real_buffer
[7] = data
->block_descriptor_length
;
1844 cmd
[0] = MODE_SELECT_10
;
1848 if (len
> 255 || data
->block_descriptor_length
> 255 ||
1852 real_buffer
= kmalloc(4 + len
, GFP_KERNEL
);
1855 memcpy(real_buffer
+ 4, buffer
, len
);
1858 real_buffer
[1] = data
->medium_type
;
1859 real_buffer
[2] = data
->device_specific
;
1860 real_buffer
[3] = data
->block_descriptor_length
;
1863 cmd
[0] = MODE_SELECT
;
1867 ret
= scsi_execute_req(sdev
, cmd
, DMA_TO_DEVICE
, real_buffer
, len
,
1868 sshdr
, timeout
, retries
, NULL
);
1872 EXPORT_SYMBOL_GPL(scsi_mode_select
);
1875 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
1876 * @sdev: SCSI device to be queried
1877 * @dbd: set if mode sense will allow block descriptors to be returned
1878 * @modepage: mode page being requested
1879 * @buffer: request buffer (may not be smaller than eight bytes)
1880 * @len: length of request buffer.
1881 * @timeout: command timeout
1882 * @retries: number of retries before failing
1883 * @data: returns a structure abstracting the mode header data
1884 * @sshdr: place to put sense data (or NULL if no sense to be collected).
1885 * must be SCSI_SENSE_BUFFERSIZE big.
1887 * Returns zero if unsuccessful, or the header offset (either 4
1888 * or 8 depending on whether a six or ten byte command was
1889 * issued) if successful.
1892 scsi_mode_sense(struct scsi_device
*sdev
, int dbd
, int modepage
,
1893 unsigned char *buffer
, int len
, int timeout
, int retries
,
1894 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
1896 unsigned char cmd
[12];
1900 struct scsi_sense_hdr my_sshdr
;
1902 memset(data
, 0, sizeof(*data
));
1903 memset(&cmd
[0], 0, 12);
1904 cmd
[1] = dbd
& 0x18; /* allows DBD and LLBA bits */
1907 /* caller might not be interested in sense, but we need it */
1912 use_10_for_ms
= sdev
->use_10_for_ms
;
1914 if (use_10_for_ms
) {
1918 cmd
[0] = MODE_SENSE_10
;
1925 cmd
[0] = MODE_SENSE
;
1930 memset(buffer
, 0, len
);
1932 result
= scsi_execute_req(sdev
, cmd
, DMA_FROM_DEVICE
, buffer
, len
,
1933 sshdr
, timeout
, retries
, NULL
);
1935 /* This code looks awful: what it's doing is making sure an
1936 * ILLEGAL REQUEST sense return identifies the actual command
1937 * byte as the problem. MODE_SENSE commands can return
1938 * ILLEGAL REQUEST if the code page isn't supported */
1940 if (use_10_for_ms
&& !scsi_status_is_good(result
) &&
1941 (driver_byte(result
) & DRIVER_SENSE
)) {
1942 if (scsi_sense_valid(sshdr
)) {
1943 if ((sshdr
->sense_key
== ILLEGAL_REQUEST
) &&
1944 (sshdr
->asc
== 0x20) && (sshdr
->ascq
== 0)) {
1946 * Invalid command operation code
1948 sdev
->use_10_for_ms
= 0;
1954 if(scsi_status_is_good(result
)) {
1955 if (unlikely(buffer
[0] == 0x86 && buffer
[1] == 0x0b &&
1956 (modepage
== 6 || modepage
== 8))) {
1957 /* Initio breakage? */
1960 data
->medium_type
= 0;
1961 data
->device_specific
= 0;
1963 data
->block_descriptor_length
= 0;
1964 } else if(use_10_for_ms
) {
1965 data
->length
= buffer
[0]*256 + buffer
[1] + 2;
1966 data
->medium_type
= buffer
[2];
1967 data
->device_specific
= buffer
[3];
1968 data
->longlba
= buffer
[4] & 0x01;
1969 data
->block_descriptor_length
= buffer
[6]*256
1972 data
->length
= buffer
[0] + 1;
1973 data
->medium_type
= buffer
[1];
1974 data
->device_specific
= buffer
[2];
1975 data
->block_descriptor_length
= buffer
[3];
1977 data
->header_length
= header_length
;
1982 EXPORT_SYMBOL(scsi_mode_sense
);
1985 * scsi_test_unit_ready - test if unit is ready
1986 * @sdev: scsi device to change the state of.
1987 * @timeout: command timeout
1988 * @retries: number of retries before failing
1989 * @sshdr_external: Optional pointer to struct scsi_sense_hdr for
1990 * returning sense. Make sure that this is cleared before passing
1993 * Returns zero if unsuccessful or an error if TUR failed. For
1994 * removable media, UNIT_ATTENTION sets ->changed flag.
1997 scsi_test_unit_ready(struct scsi_device
*sdev
, int timeout
, int retries
,
1998 struct scsi_sense_hdr
*sshdr_external
)
2001 TEST_UNIT_READY
, 0, 0, 0, 0, 0,
2003 struct scsi_sense_hdr
*sshdr
;
2006 if (!sshdr_external
)
2007 sshdr
= kzalloc(sizeof(*sshdr
), GFP_KERNEL
);
2009 sshdr
= sshdr_external
;
2011 /* try to eat the UNIT_ATTENTION if there are enough retries */
2013 result
= scsi_execute_req(sdev
, cmd
, DMA_NONE
, NULL
, 0, sshdr
,
2014 timeout
, retries
, NULL
);
2015 if (sdev
->removable
&& scsi_sense_valid(sshdr
) &&
2016 sshdr
->sense_key
== UNIT_ATTENTION
)
2018 } while (scsi_sense_valid(sshdr
) &&
2019 sshdr
->sense_key
== UNIT_ATTENTION
&& --retries
);
2021 if (!sshdr_external
)
2025 EXPORT_SYMBOL(scsi_test_unit_ready
);
2028 * scsi_device_set_state - Take the given device through the device state model.
2029 * @sdev: scsi device to change the state of.
2030 * @state: state to change to.
2032 * Returns zero if unsuccessful or an error if the requested
2033 * transition is illegal.
2036 scsi_device_set_state(struct scsi_device
*sdev
, enum scsi_device_state state
)
2038 enum scsi_device_state oldstate
= sdev
->sdev_state
;
2040 if (state
== oldstate
)
2046 case SDEV_CREATED_BLOCK
:
2057 case SDEV_TRANSPORT_OFFLINE
:
2070 case SDEV_TRANSPORT_OFFLINE
:
2078 case SDEV_TRANSPORT_OFFLINE
:
2093 case SDEV_CREATED_BLOCK
:
2100 case SDEV_CREATED_BLOCK
:
2115 case SDEV_TRANSPORT_OFFLINE
:
2128 case SDEV_TRANSPORT_OFFLINE
:
2130 case SDEV_CREATED_BLOCK
:
2138 sdev
->sdev_state
= state
;
2142 SCSI_LOG_ERROR_RECOVERY(1,
2143 sdev_printk(KERN_ERR
, sdev
,
2144 "Illegal state transition %s->%s\n",
2145 scsi_device_state_name(oldstate
),
2146 scsi_device_state_name(state
))
2150 EXPORT_SYMBOL(scsi_device_set_state
);
2153 * sdev_evt_emit - emit a single SCSI device uevent
2154 * @sdev: associated SCSI device
2155 * @evt: event to emit
2157 * Send a single uevent (scsi_event) to the associated scsi_device.
2159 static void scsi_evt_emit(struct scsi_device
*sdev
, struct scsi_event
*evt
)
2164 switch (evt
->evt_type
) {
2165 case SDEV_EVT_MEDIA_CHANGE
:
2166 envp
[idx
++] = "SDEV_MEDIA_CHANGE=1";
2168 case SDEV_EVT_INQUIRY_CHANGE_REPORTED
:
2169 envp
[idx
++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2171 case SDEV_EVT_CAPACITY_CHANGE_REPORTED
:
2172 envp
[idx
++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2174 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED
:
2175 envp
[idx
++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2177 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED
:
2178 envp
[idx
++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2180 case SDEV_EVT_LUN_CHANGE_REPORTED
:
2181 envp
[idx
++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2190 kobject_uevent_env(&sdev
->sdev_gendev
.kobj
, KOBJ_CHANGE
, envp
);
2194 * sdev_evt_thread - send a uevent for each scsi event
2195 * @work: work struct for scsi_device
2197 * Dispatch queued events to their associated scsi_device kobjects
2200 void scsi_evt_thread(struct work_struct
*work
)
2202 struct scsi_device
*sdev
;
2203 enum scsi_device_event evt_type
;
2204 LIST_HEAD(event_list
);
2206 sdev
= container_of(work
, struct scsi_device
, event_work
);
2208 for (evt_type
= SDEV_EVT_FIRST
; evt_type
<= SDEV_EVT_LAST
; evt_type
++)
2209 if (test_and_clear_bit(evt_type
, sdev
->pending_events
))
2210 sdev_evt_send_simple(sdev
, evt_type
, GFP_KERNEL
);
2213 struct scsi_event
*evt
;
2214 struct list_head
*this, *tmp
;
2215 unsigned long flags
;
2217 spin_lock_irqsave(&sdev
->list_lock
, flags
);
2218 list_splice_init(&sdev
->event_list
, &event_list
);
2219 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
2221 if (list_empty(&event_list
))
2224 list_for_each_safe(this, tmp
, &event_list
) {
2225 evt
= list_entry(this, struct scsi_event
, node
);
2226 list_del(&evt
->node
);
2227 scsi_evt_emit(sdev
, evt
);
2234 * sdev_evt_send - send asserted event to uevent thread
2235 * @sdev: scsi_device event occurred on
2236 * @evt: event to send
2238 * Assert scsi device event asynchronously.
2240 void sdev_evt_send(struct scsi_device
*sdev
, struct scsi_event
*evt
)
2242 unsigned long flags
;
2245 /* FIXME: currently this check eliminates all media change events
2246 * for polled devices. Need to update to discriminate between AN
2247 * and polled events */
2248 if (!test_bit(evt
->evt_type
, sdev
->supported_events
)) {
2254 spin_lock_irqsave(&sdev
->list_lock
, flags
);
2255 list_add_tail(&evt
->node
, &sdev
->event_list
);
2256 schedule_work(&sdev
->event_work
);
2257 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
2259 EXPORT_SYMBOL_GPL(sdev_evt_send
);
2262 * sdev_evt_alloc - allocate a new scsi event
2263 * @evt_type: type of event to allocate
2264 * @gfpflags: GFP flags for allocation
2266 * Allocates and returns a new scsi_event.
2268 struct scsi_event
*sdev_evt_alloc(enum scsi_device_event evt_type
,
2271 struct scsi_event
*evt
= kzalloc(sizeof(struct scsi_event
), gfpflags
);
2275 evt
->evt_type
= evt_type
;
2276 INIT_LIST_HEAD(&evt
->node
);
2278 /* evt_type-specific initialization, if any */
2280 case SDEV_EVT_MEDIA_CHANGE
:
2281 case SDEV_EVT_INQUIRY_CHANGE_REPORTED
:
2282 case SDEV_EVT_CAPACITY_CHANGE_REPORTED
:
2283 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED
:
2284 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED
:
2285 case SDEV_EVT_LUN_CHANGE_REPORTED
:
2293 EXPORT_SYMBOL_GPL(sdev_evt_alloc
);
2296 * sdev_evt_send_simple - send asserted event to uevent thread
2297 * @sdev: scsi_device event occurred on
2298 * @evt_type: type of event to send
2299 * @gfpflags: GFP flags for allocation
2301 * Assert scsi device event asynchronously, given an event type.
2303 void sdev_evt_send_simple(struct scsi_device
*sdev
,
2304 enum scsi_device_event evt_type
, gfp_t gfpflags
)
2306 struct scsi_event
*evt
= sdev_evt_alloc(evt_type
, gfpflags
);
2308 sdev_printk(KERN_ERR
, sdev
, "event %d eaten due to OOM\n",
2313 sdev_evt_send(sdev
, evt
);
2315 EXPORT_SYMBOL_GPL(sdev_evt_send_simple
);
2318 * scsi_device_quiesce - Block user issued commands.
2319 * @sdev: scsi device to quiesce.
2321 * This works by trying to transition to the SDEV_QUIESCE state
2322 * (which must be a legal transition). When the device is in this
2323 * state, only special requests will be accepted, all others will
2324 * be deferred. Since special requests may also be requeued requests,
2325 * a successful return doesn't guarantee the device will be
2326 * totally quiescent.
2328 * Must be called with user context, may sleep.
2330 * Returns zero if unsuccessful or an error if not.
2333 scsi_device_quiesce(struct scsi_device
*sdev
)
2335 int err
= scsi_device_set_state(sdev
, SDEV_QUIESCE
);
2339 scsi_run_queue(sdev
->request_queue
);
2340 while (sdev
->device_busy
) {
2341 msleep_interruptible(200);
2342 scsi_run_queue(sdev
->request_queue
);
2346 EXPORT_SYMBOL(scsi_device_quiesce
);
2349 * scsi_device_resume - Restart user issued commands to a quiesced device.
2350 * @sdev: scsi device to resume.
2352 * Moves the device from quiesced back to running and restarts the
2355 * Must be called with user context, may sleep.
2357 void scsi_device_resume(struct scsi_device
*sdev
)
2359 /* check if the device state was mutated prior to resume, and if
2360 * so assume the state is being managed elsewhere (for example
2361 * device deleted during suspend)
2363 if (sdev
->sdev_state
!= SDEV_QUIESCE
||
2364 scsi_device_set_state(sdev
, SDEV_RUNNING
))
2366 scsi_run_queue(sdev
->request_queue
);
2368 EXPORT_SYMBOL(scsi_device_resume
);
2371 device_quiesce_fn(struct scsi_device
*sdev
, void *data
)
2373 scsi_device_quiesce(sdev
);
2377 scsi_target_quiesce(struct scsi_target
*starget
)
2379 starget_for_each_device(starget
, NULL
, device_quiesce_fn
);
2381 EXPORT_SYMBOL(scsi_target_quiesce
);
2384 device_resume_fn(struct scsi_device
*sdev
, void *data
)
2386 scsi_device_resume(sdev
);
2390 scsi_target_resume(struct scsi_target
*starget
)
2392 starget_for_each_device(starget
, NULL
, device_resume_fn
);
2394 EXPORT_SYMBOL(scsi_target_resume
);
2397 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state
2398 * @sdev: device to block
2400 * Block request made by scsi lld's to temporarily stop all
2401 * scsi commands on the specified device. Called from interrupt
2402 * or normal process context.
2404 * Returns zero if successful or error if not
2407 * This routine transitions the device to the SDEV_BLOCK state
2408 * (which must be a legal transition). When the device is in this
2409 * state, all commands are deferred until the scsi lld reenables
2410 * the device with scsi_device_unblock or device_block_tmo fires.
2413 scsi_internal_device_block(struct scsi_device
*sdev
)
2415 struct request_queue
*q
= sdev
->request_queue
;
2416 unsigned long flags
;
2419 err
= scsi_device_set_state(sdev
, SDEV_BLOCK
);
2421 err
= scsi_device_set_state(sdev
, SDEV_CREATED_BLOCK
);
2428 * The device has transitioned to SDEV_BLOCK. Stop the
2429 * block layer from calling the midlayer with this device's
2432 spin_lock_irqsave(q
->queue_lock
, flags
);
2434 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2438 EXPORT_SYMBOL_GPL(scsi_internal_device_block
);
2441 * scsi_internal_device_unblock - resume a device after a block request
2442 * @sdev: device to resume
2443 * @new_state: state to set devices to after unblocking
2445 * Called by scsi lld's or the midlayer to restart the device queue
2446 * for the previously suspended scsi device. Called from interrupt or
2447 * normal process context.
2449 * Returns zero if successful or error if not.
2452 * This routine transitions the device to the SDEV_RUNNING state
2453 * or to one of the offline states (which must be a legal transition)
2454 * allowing the midlayer to goose the queue for this device.
2457 scsi_internal_device_unblock(struct scsi_device
*sdev
,
2458 enum scsi_device_state new_state
)
2460 struct request_queue
*q
= sdev
->request_queue
;
2461 unsigned long flags
;
2464 * Try to transition the scsi device to SDEV_RUNNING or one of the
2465 * offlined states and goose the device queue if successful.
2467 if ((sdev
->sdev_state
== SDEV_BLOCK
) ||
2468 (sdev
->sdev_state
== SDEV_TRANSPORT_OFFLINE
))
2469 sdev
->sdev_state
= new_state
;
2470 else if (sdev
->sdev_state
== SDEV_CREATED_BLOCK
) {
2471 if (new_state
== SDEV_TRANSPORT_OFFLINE
||
2472 new_state
== SDEV_OFFLINE
)
2473 sdev
->sdev_state
= new_state
;
2475 sdev
->sdev_state
= SDEV_CREATED
;
2476 } else if (sdev
->sdev_state
!= SDEV_CANCEL
&&
2477 sdev
->sdev_state
!= SDEV_OFFLINE
)
2480 spin_lock_irqsave(q
->queue_lock
, flags
);
2482 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2486 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock
);
2489 device_block(struct scsi_device
*sdev
, void *data
)
2491 scsi_internal_device_block(sdev
);
2495 target_block(struct device
*dev
, void *data
)
2497 if (scsi_is_target_device(dev
))
2498 starget_for_each_device(to_scsi_target(dev
), NULL
,
2504 scsi_target_block(struct device
*dev
)
2506 if (scsi_is_target_device(dev
))
2507 starget_for_each_device(to_scsi_target(dev
), NULL
,
2510 device_for_each_child(dev
, NULL
, target_block
);
2512 EXPORT_SYMBOL_GPL(scsi_target_block
);
2515 device_unblock(struct scsi_device
*sdev
, void *data
)
2517 scsi_internal_device_unblock(sdev
, *(enum scsi_device_state
*)data
);
2521 target_unblock(struct device
*dev
, void *data
)
2523 if (scsi_is_target_device(dev
))
2524 starget_for_each_device(to_scsi_target(dev
), data
,
2530 scsi_target_unblock(struct device
*dev
, enum scsi_device_state new_state
)
2532 if (scsi_is_target_device(dev
))
2533 starget_for_each_device(to_scsi_target(dev
), &new_state
,
2536 device_for_each_child(dev
, &new_state
, target_unblock
);
2538 EXPORT_SYMBOL_GPL(scsi_target_unblock
);
2541 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
2542 * @sgl: scatter-gather list
2543 * @sg_count: number of segments in sg
2544 * @offset: offset in bytes into sg, on return offset into the mapped area
2545 * @len: bytes to map, on return number of bytes mapped
2547 * Returns virtual address of the start of the mapped page
2549 void *scsi_kmap_atomic_sg(struct scatterlist
*sgl
, int sg_count
,
2550 size_t *offset
, size_t *len
)
2553 size_t sg_len
= 0, len_complete
= 0;
2554 struct scatterlist
*sg
;
2557 WARN_ON(!irqs_disabled());
2559 for_each_sg(sgl
, sg
, sg_count
, i
) {
2560 len_complete
= sg_len
; /* Complete sg-entries */
2561 sg_len
+= sg
->length
;
2562 if (sg_len
> *offset
)
2566 if (unlikely(i
== sg_count
)) {
2567 printk(KERN_ERR
"%s: Bytes in sg: %zu, requested offset %zu, "
2569 __func__
, sg_len
, *offset
, sg_count
);
2574 /* Offset starting from the beginning of first page in this sg-entry */
2575 *offset
= *offset
- len_complete
+ sg
->offset
;
2577 /* Assumption: contiguous pages can be accessed as "page + i" */
2578 page
= nth_page(sg_page(sg
), (*offset
>> PAGE_SHIFT
));
2579 *offset
&= ~PAGE_MASK
;
2581 /* Bytes in this sg-entry from *offset to the end of the page */
2582 sg_len
= PAGE_SIZE
- *offset
;
2586 return kmap_atomic(page
);
2588 EXPORT_SYMBOL(scsi_kmap_atomic_sg
);
2591 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
2592 * @virt: virtual address to be unmapped
2594 void scsi_kunmap_atomic_sg(void *virt
)
2596 kunmap_atomic(virt
);
2598 EXPORT_SYMBOL(scsi_kunmap_atomic_sg
);
2600 void sdev_disable_disk_events(struct scsi_device
*sdev
)
2602 atomic_inc(&sdev
->disk_events_disable_depth
);
2604 EXPORT_SYMBOL(sdev_disable_disk_events
);
2606 void sdev_enable_disk_events(struct scsi_device
*sdev
)
2608 if (WARN_ON_ONCE(atomic_read(&sdev
->disk_events_disable_depth
) <= 0))
2610 atomic_dec(&sdev
->disk_events_disable_depth
);
2612 EXPORT_SYMBOL(sdev_enable_disk_events
);