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.
140 spin_lock_irqsave(q
->queue_lock
, flags
);
141 blk_requeue_request(q
, cmd
->request
);
142 kblockd_schedule_work(q
, &device
->requeue_work
);
143 spin_unlock_irqrestore(q
->queue_lock
, flags
);
147 * Function: scsi_queue_insert()
149 * Purpose: Insert a command in the midlevel queue.
151 * Arguments: cmd - command that we are adding to queue.
152 * reason - why we are inserting command to queue.
154 * Lock status: Assumed that lock is not held upon entry.
158 * Notes: We do this for one of two cases. Either the host is busy
159 * and it cannot accept any more commands for the time being,
160 * or the device returned QUEUE_FULL and can accept no more
162 * Notes: This could be called either from an interrupt context or a
163 * normal process context.
165 void scsi_queue_insert(struct scsi_cmnd
*cmd
, int reason
)
167 __scsi_queue_insert(cmd
, reason
, 1);
170 * scsi_execute - insert request and wait for the result
173 * @data_direction: data direction
174 * @buffer: data buffer
175 * @bufflen: len of buffer
176 * @sense: optional sense buffer
177 * @timeout: request timeout in seconds
178 * @retries: number of times to retry request
179 * @flags: or into request flags;
180 * @resid: optional residual length
182 * returns the req->errors value which is the scsi_cmnd result
185 int scsi_execute(struct scsi_device
*sdev
, const unsigned char *cmd
,
186 int data_direction
, void *buffer
, unsigned bufflen
,
187 unsigned char *sense
, int timeout
, int retries
, u64 flags
,
191 int write
= (data_direction
== DMA_TO_DEVICE
);
192 int ret
= DRIVER_ERROR
<< 24;
194 req
= blk_get_request(sdev
->request_queue
, write
, __GFP_WAIT
);
198 if (bufflen
&& blk_rq_map_kern(sdev
->request_queue
, req
,
199 buffer
, bufflen
, __GFP_WAIT
))
202 req
->cmd_len
= COMMAND_SIZE(cmd
[0]);
203 memcpy(req
->cmd
, cmd
, req
->cmd_len
);
206 req
->retries
= retries
;
207 req
->timeout
= timeout
;
208 req
->cmd_type
= REQ_TYPE_BLOCK_PC
;
209 req
->cmd_flags
|= flags
| REQ_QUIET
| REQ_PREEMPT
;
212 * head injection *required* here otherwise quiesce won't work
214 blk_execute_rq(req
->q
, NULL
, req
, 1);
217 * Some devices (USB mass-storage in particular) may transfer
218 * garbage data together with a residue indicating that the data
219 * is invalid. Prevent the garbage from being misinterpreted
220 * and prevent security leaks by zeroing out the excess data.
222 if (unlikely(req
->resid_len
> 0 && req
->resid_len
<= bufflen
))
223 memset(buffer
+ (bufflen
- req
->resid_len
), 0, req
->resid_len
);
226 *resid
= req
->resid_len
;
229 blk_put_request(req
);
233 EXPORT_SYMBOL(scsi_execute
);
235 int scsi_execute_req_flags(struct scsi_device
*sdev
, const unsigned char *cmd
,
236 int data_direction
, void *buffer
, unsigned bufflen
,
237 struct scsi_sense_hdr
*sshdr
, int timeout
, int retries
,
238 int *resid
, u64 flags
)
244 sense
= kzalloc(SCSI_SENSE_BUFFERSIZE
, GFP_NOIO
);
246 return DRIVER_ERROR
<< 24;
248 result
= scsi_execute(sdev
, cmd
, data_direction
, buffer
, bufflen
,
249 sense
, timeout
, retries
, flags
, resid
);
251 scsi_normalize_sense(sense
, SCSI_SENSE_BUFFERSIZE
, sshdr
);
256 EXPORT_SYMBOL(scsi_execute_req_flags
);
259 * Function: scsi_init_cmd_errh()
261 * Purpose: Initialize cmd fields related to error handling.
263 * Arguments: cmd - command that is ready to be queued.
265 * Notes: This function has the job of initializing a number of
266 * fields related to error handling. Typically this will
267 * be called once for each command, as required.
269 static void scsi_init_cmd_errh(struct scsi_cmnd
*cmd
)
271 cmd
->serial_number
= 0;
272 scsi_set_resid(cmd
, 0);
273 memset(cmd
->sense_buffer
, 0, SCSI_SENSE_BUFFERSIZE
);
274 if (cmd
->cmd_len
== 0)
275 cmd
->cmd_len
= scsi_command_size(cmd
->cmnd
);
278 void scsi_device_unbusy(struct scsi_device
*sdev
)
280 struct Scsi_Host
*shost
= sdev
->host
;
281 struct scsi_target
*starget
= scsi_target(sdev
);
284 spin_lock_irqsave(shost
->host_lock
, flags
);
286 starget
->target_busy
--;
287 if (unlikely(scsi_host_in_recovery(shost
) &&
288 (shost
->host_failed
|| shost
->host_eh_scheduled
)))
289 scsi_eh_wakeup(shost
);
290 spin_unlock(shost
->host_lock
);
291 spin_lock(sdev
->request_queue
->queue_lock
);
293 spin_unlock_irqrestore(sdev
->request_queue
->queue_lock
, flags
);
297 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
298 * and call blk_run_queue for all the scsi_devices on the target -
299 * including current_sdev first.
301 * Called with *no* scsi locks held.
303 static void scsi_single_lun_run(struct scsi_device
*current_sdev
)
305 struct Scsi_Host
*shost
= current_sdev
->host
;
306 struct scsi_device
*sdev
, *tmp
;
307 struct scsi_target
*starget
= scsi_target(current_sdev
);
310 spin_lock_irqsave(shost
->host_lock
, flags
);
311 starget
->starget_sdev_user
= NULL
;
312 spin_unlock_irqrestore(shost
->host_lock
, flags
);
315 * Call blk_run_queue for all LUNs on the target, starting with
316 * current_sdev. We race with others (to set starget_sdev_user),
317 * but in most cases, we will be first. Ideally, each LU on the
318 * target would get some limited time or requests on the target.
320 blk_run_queue(current_sdev
->request_queue
);
322 spin_lock_irqsave(shost
->host_lock
, flags
);
323 if (starget
->starget_sdev_user
)
325 list_for_each_entry_safe(sdev
, tmp
, &starget
->devices
,
326 same_target_siblings
) {
327 if (sdev
== current_sdev
)
329 if (scsi_device_get(sdev
))
332 spin_unlock_irqrestore(shost
->host_lock
, flags
);
333 blk_run_queue(sdev
->request_queue
);
334 spin_lock_irqsave(shost
->host_lock
, flags
);
336 scsi_device_put(sdev
);
339 spin_unlock_irqrestore(shost
->host_lock
, flags
);
342 static inline int scsi_device_is_busy(struct scsi_device
*sdev
)
344 if (sdev
->device_busy
>= sdev
->queue_depth
|| sdev
->device_blocked
)
350 static inline int scsi_target_is_busy(struct scsi_target
*starget
)
352 return ((starget
->can_queue
> 0 &&
353 starget
->target_busy
>= starget
->can_queue
) ||
354 starget
->target_blocked
);
357 static inline int scsi_host_is_busy(struct Scsi_Host
*shost
)
359 if ((shost
->can_queue
> 0 && shost
->host_busy
>= shost
->can_queue
) ||
360 shost
->host_blocked
|| shost
->host_self_blocked
)
366 static void scsi_starved_list_run(struct Scsi_Host
*shost
)
368 LIST_HEAD(starved_list
);
369 struct scsi_device
*sdev
;
372 spin_lock_irqsave(shost
->host_lock
, flags
);
373 list_splice_init(&shost
->starved_list
, &starved_list
);
375 while (!list_empty(&starved_list
)) {
376 struct request_queue
*slq
;
379 * As long as shost is accepting commands and we have
380 * starved queues, call blk_run_queue. scsi_request_fn
381 * drops the queue_lock and can add us back to the
384 * host_lock protects the starved_list and starved_entry.
385 * scsi_request_fn must get the host_lock before checking
386 * or modifying starved_list or starved_entry.
388 if (scsi_host_is_busy(shost
))
391 sdev
= list_entry(starved_list
.next
,
392 struct scsi_device
, starved_entry
);
393 list_del_init(&sdev
->starved_entry
);
394 if (scsi_target_is_busy(scsi_target(sdev
))) {
395 list_move_tail(&sdev
->starved_entry
,
396 &shost
->starved_list
);
401 * Once we drop the host lock, a racing scsi_remove_device()
402 * call may remove the sdev from the starved list and destroy
403 * it and the queue. Mitigate by taking a reference to the
404 * queue and never touching the sdev again after we drop the
405 * host lock. Note: if __scsi_remove_device() invokes
406 * blk_cleanup_queue() before the queue is run from this
407 * function then blk_run_queue() will return immediately since
408 * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING.
410 slq
= sdev
->request_queue
;
411 if (!blk_get_queue(slq
))
413 spin_unlock_irqrestore(shost
->host_lock
, flags
);
418 spin_lock_irqsave(shost
->host_lock
, flags
);
420 /* put any unprocessed entries back */
421 list_splice(&starved_list
, &shost
->starved_list
);
422 spin_unlock_irqrestore(shost
->host_lock
, flags
);
426 * Function: scsi_run_queue()
428 * Purpose: Select a proper request queue to serve next
430 * Arguments: q - last request's queue
434 * Notes: The previous command was completely finished, start
435 * a new one if possible.
437 static void scsi_run_queue(struct request_queue
*q
)
439 struct scsi_device
*sdev
= q
->queuedata
;
441 if (scsi_target(sdev
)->single_lun
)
442 scsi_single_lun_run(sdev
);
443 if (!list_empty(&sdev
->host
->starved_list
))
444 scsi_starved_list_run(sdev
->host
);
449 void scsi_requeue_run_queue(struct work_struct
*work
)
451 struct scsi_device
*sdev
;
452 struct request_queue
*q
;
454 sdev
= container_of(work
, struct scsi_device
, requeue_work
);
455 q
= sdev
->request_queue
;
460 * Function: scsi_requeue_command()
462 * Purpose: Handle post-processing of completed commands.
464 * Arguments: q - queue to operate on
465 * cmd - command that may need to be requeued.
469 * Notes: After command completion, there may be blocks left
470 * over which weren't finished by the previous command
471 * this can be for a number of reasons - the main one is
472 * I/O errors in the middle of the request, in which case
473 * we need to request the blocks that come after the bad
475 * Notes: Upon return, cmd is a stale pointer.
477 static void scsi_requeue_command(struct request_queue
*q
, struct scsi_cmnd
*cmd
)
479 struct scsi_device
*sdev
= cmd
->device
;
480 struct request
*req
= cmd
->request
;
483 spin_lock_irqsave(q
->queue_lock
, flags
);
484 blk_unprep_request(req
);
486 scsi_put_command(cmd
);
487 blk_requeue_request(q
, req
);
488 spin_unlock_irqrestore(q
->queue_lock
, flags
);
492 put_device(&sdev
->sdev_gendev
);
495 void scsi_next_command(struct scsi_cmnd
*cmd
)
497 struct scsi_device
*sdev
= cmd
->device
;
498 struct request_queue
*q
= sdev
->request_queue
;
500 scsi_put_command(cmd
);
503 put_device(&sdev
->sdev_gendev
);
506 void scsi_run_host_queues(struct Scsi_Host
*shost
)
508 struct scsi_device
*sdev
;
510 shost_for_each_device(sdev
, shost
)
511 scsi_run_queue(sdev
->request_queue
);
514 static void __scsi_release_buffers(struct scsi_cmnd
*, int);
517 * Function: scsi_end_request()
519 * Purpose: Post-processing of completed commands (usually invoked at end
520 * of upper level post-processing and scsi_io_completion).
522 * Arguments: cmd - command that is complete.
523 * error - 0 if I/O indicates success, < 0 for I/O error.
524 * bytes - number of bytes of completed I/O
525 * requeue - indicates whether we should requeue leftovers.
527 * Lock status: Assumed that lock is not held upon entry.
529 * Returns: cmd if requeue required, NULL otherwise.
531 * Notes: This is called for block device requests in order to
532 * mark some number of sectors as complete.
534 * We are guaranteeing that the request queue will be goosed
535 * at some point during this call.
536 * Notes: If cmd was requeued, upon return it will be a stale pointer.
538 static struct scsi_cmnd
*scsi_end_request(struct scsi_cmnd
*cmd
, int error
,
539 int bytes
, int requeue
)
541 struct request_queue
*q
= cmd
->device
->request_queue
;
542 struct request
*req
= cmd
->request
;
545 * If there are blocks left over at the end, set up the command
546 * to queue the remainder of them.
548 if (blk_end_request(req
, error
, bytes
)) {
549 /* kill remainder if no retrys */
550 if (error
&& scsi_noretry_cmd(cmd
))
551 blk_end_request_all(req
, error
);
555 * Bleah. Leftovers again. Stick the
556 * leftovers in the front of the
557 * queue, and goose the queue again.
559 scsi_release_buffers(cmd
);
560 scsi_requeue_command(q
, cmd
);
568 * This will goose the queue request function at the end, so we don't
569 * need to worry about launching another command.
571 __scsi_release_buffers(cmd
, 0);
572 scsi_next_command(cmd
);
576 static inline unsigned int scsi_sgtable_index(unsigned short nents
)
580 BUG_ON(nents
> SCSI_MAX_SG_SEGMENTS
);
585 index
= get_count_order(nents
) - 3;
590 static void scsi_sg_free(struct scatterlist
*sgl
, unsigned int nents
)
592 struct scsi_host_sg_pool
*sgp
;
594 sgp
= scsi_sg_pools
+ scsi_sgtable_index(nents
);
595 mempool_free(sgl
, sgp
->pool
);
598 static struct scatterlist
*scsi_sg_alloc(unsigned int nents
, gfp_t gfp_mask
)
600 struct scsi_host_sg_pool
*sgp
;
602 sgp
= scsi_sg_pools
+ scsi_sgtable_index(nents
);
603 return mempool_alloc(sgp
->pool
, gfp_mask
);
606 static int scsi_alloc_sgtable(struct scsi_data_buffer
*sdb
, int nents
,
613 ret
= __sg_alloc_table(&sdb
->table
, nents
, SCSI_MAX_SG_SEGMENTS
,
614 gfp_mask
, scsi_sg_alloc
);
616 __sg_free_table(&sdb
->table
, SCSI_MAX_SG_SEGMENTS
,
622 static void scsi_free_sgtable(struct scsi_data_buffer
*sdb
)
624 __sg_free_table(&sdb
->table
, SCSI_MAX_SG_SEGMENTS
, scsi_sg_free
);
627 static void __scsi_release_buffers(struct scsi_cmnd
*cmd
, int do_bidi_check
)
630 if (cmd
->sdb
.table
.nents
)
631 scsi_free_sgtable(&cmd
->sdb
);
633 memset(&cmd
->sdb
, 0, sizeof(cmd
->sdb
));
635 if (do_bidi_check
&& scsi_bidi_cmnd(cmd
)) {
636 struct scsi_data_buffer
*bidi_sdb
=
637 cmd
->request
->next_rq
->special
;
638 scsi_free_sgtable(bidi_sdb
);
639 kmem_cache_free(scsi_sdb_cache
, bidi_sdb
);
640 cmd
->request
->next_rq
->special
= NULL
;
643 if (scsi_prot_sg_count(cmd
))
644 scsi_free_sgtable(cmd
->prot_sdb
);
648 * Function: scsi_release_buffers()
650 * Purpose: Completion processing for block device I/O requests.
652 * Arguments: cmd - command that we are bailing.
654 * Lock status: Assumed that no lock is held upon entry.
658 * Notes: In the event that an upper level driver rejects a
659 * command, we must release resources allocated during
660 * the __init_io() function. Primarily this would involve
661 * the scatter-gather table, and potentially any bounce
664 void scsi_release_buffers(struct scsi_cmnd
*cmd
)
666 __scsi_release_buffers(cmd
, 1);
668 EXPORT_SYMBOL(scsi_release_buffers
);
671 * __scsi_error_from_host_byte - translate SCSI error code into errno
672 * @cmd: SCSI command (unused)
673 * @result: scsi error code
675 * Translate SCSI error code into standard UNIX errno.
677 * -ENOLINK temporary transport failure
678 * -EREMOTEIO permanent target failure, do not retry
679 * -EBADE permanent nexus failure, retry on other path
680 * -ENOSPC No write space available
681 * -ENODATA Medium error
682 * -EIO unspecified I/O error
684 static int __scsi_error_from_host_byte(struct scsi_cmnd
*cmd
, int result
)
688 switch(host_byte(result
)) {
689 case DID_TRANSPORT_FAILFAST
:
692 case DID_TARGET_FAILURE
:
693 set_host_byte(cmd
, DID_OK
);
696 case DID_NEXUS_FAILURE
:
697 set_host_byte(cmd
, DID_OK
);
700 case DID_ALLOC_FAILURE
:
701 set_host_byte(cmd
, DID_OK
);
704 case DID_MEDIUM_ERROR
:
705 set_host_byte(cmd
, DID_OK
);
717 * Function: scsi_io_completion()
719 * Purpose: Completion processing for block device I/O requests.
721 * Arguments: cmd - command that is finished.
723 * Lock status: Assumed that no lock is held upon entry.
727 * Notes: This function is matched in terms of capabilities to
728 * the function that created the scatter-gather list.
729 * In other words, if there are no bounce buffers
730 * (the normal case for most drivers), we don't need
731 * the logic to deal with cleaning up afterwards.
733 * We must call scsi_end_request(). This will finish off
734 * the specified number of sectors. If we are done, the
735 * command block will be released and the queue function
736 * will be goosed. If we are not done then we have to
737 * figure out what to do next:
739 * a) We can call scsi_requeue_command(). The request
740 * will be unprepared and put back on the queue. Then
741 * a new command will be created for it. This should
742 * be used if we made forward progress, or if we want
743 * to switch from READ(10) to READ(6) for example.
745 * b) We can call scsi_queue_insert(). The request will
746 * be put back on the queue and retried using the same
747 * command as before, possibly after a delay.
749 * c) We can call blk_end_request() with -EIO to fail
750 * the remainder of the request.
752 void scsi_io_completion(struct scsi_cmnd
*cmd
, unsigned int good_bytes
)
754 int result
= cmd
->result
;
755 struct request_queue
*q
= cmd
->device
->request_queue
;
756 struct request
*req
= cmd
->request
;
758 struct scsi_sense_hdr sshdr
;
760 int sense_deferred
= 0;
761 enum {ACTION_FAIL
, ACTION_REPREP
, ACTION_RETRY
,
762 ACTION_DELAYED_RETRY
} action
;
763 char *description
= NULL
;
764 unsigned long wait_for
= (cmd
->allowed
+ 1) * req
->timeout
;
767 sense_valid
= scsi_command_normalize_sense(cmd
, &sshdr
);
769 sense_deferred
= scsi_sense_is_deferred(&sshdr
);
772 if (req
->cmd_type
== REQ_TYPE_BLOCK_PC
) { /* SG_IO ioctl from block level */
774 if (sense_valid
&& req
->sense
) {
776 * SG_IO wants current and deferred errors
778 int len
= 8 + cmd
->sense_buffer
[7];
780 if (len
> SCSI_SENSE_BUFFERSIZE
)
781 len
= SCSI_SENSE_BUFFERSIZE
;
782 memcpy(req
->sense
, cmd
->sense_buffer
, len
);
783 req
->sense_len
= len
;
786 error
= __scsi_error_from_host_byte(cmd
, result
);
789 * __scsi_error_from_host_byte may have reset the host_byte
791 req
->errors
= cmd
->result
;
793 req
->resid_len
= scsi_get_resid(cmd
);
795 if (scsi_bidi_cmnd(cmd
)) {
797 * Bidi commands Must be complete as a whole,
798 * both sides at once.
800 req
->next_rq
->resid_len
= scsi_in(cmd
)->resid
;
802 scsi_release_buffers(cmd
);
803 blk_end_request_all(req
, 0);
805 scsi_next_command(cmd
);
810 /* no bidi support for !REQ_TYPE_BLOCK_PC yet */
811 BUG_ON(blk_bidi_rq(req
));
814 * Next deal with any sectors which we were able to correctly
817 SCSI_LOG_HLCOMPLETE(1, printk("%u sectors total, "
819 blk_rq_sectors(req
), good_bytes
));
822 * Recovered errors need reporting, but they're always treated
823 * as success, so fiddle the result code here. For BLOCK_PC
824 * we already took a copy of the original into rq->errors which
825 * is what gets returned to the user
827 if (sense_valid
&& (sshdr
.sense_key
== RECOVERED_ERROR
)) {
828 /* if ATA PASS-THROUGH INFORMATION AVAILABLE skip
829 * print since caller wants ATA registers. Only occurs on
830 * SCSI ATA PASS_THROUGH commands when CK_COND=1
832 if ((sshdr
.asc
== 0x0) && (sshdr
.ascq
== 0x1d))
834 else if (!(req
->cmd_flags
& REQ_QUIET
))
835 scsi_print_sense("", cmd
);
837 /* BLOCK_PC may have set error */
842 * A number of bytes were successfully read. If there
843 * are leftovers and there is some kind of error
844 * (result != 0), retry the rest.
846 if (scsi_end_request(cmd
, error
, good_bytes
, result
== 0) == NULL
)
849 error
= __scsi_error_from_host_byte(cmd
, result
);
851 if (host_byte(result
) == DID_RESET
) {
852 /* Third party bus reset or reset for error recovery
853 * reasons. Just retry the command and see what
856 action
= ACTION_RETRY
;
857 } else if (sense_valid
&& !sense_deferred
) {
858 switch (sshdr
.sense_key
) {
860 if (cmd
->device
->removable
) {
861 /* Detected disc change. Set a bit
862 * and quietly refuse further access.
864 cmd
->device
->changed
= 1;
865 description
= "Media Changed";
866 action
= ACTION_FAIL
;
868 /* Must have been a power glitch, or a
869 * bus reset. Could not have been a
870 * media change, so we just retry the
871 * command and see what happens.
873 action
= ACTION_RETRY
;
876 case ILLEGAL_REQUEST
:
877 /* If we had an ILLEGAL REQUEST returned, then
878 * we may have performed an unsupported
879 * command. The only thing this should be
880 * would be a ten byte read where only a six
881 * byte read was supported. Also, on a system
882 * where READ CAPACITY failed, we may have
883 * read past the end of the disk.
885 if ((cmd
->device
->use_10_for_rw
&&
886 sshdr
.asc
== 0x20 && sshdr
.ascq
== 0x00) &&
887 (cmd
->cmnd
[0] == READ_10
||
888 cmd
->cmnd
[0] == WRITE_10
)) {
889 /* This will issue a new 6-byte command. */
890 cmd
->device
->use_10_for_rw
= 0;
891 action
= ACTION_REPREP
;
892 } else if (sshdr
.asc
== 0x10) /* DIX */ {
893 description
= "Host Data Integrity Failure";
894 action
= ACTION_FAIL
;
896 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
897 } else if (sshdr
.asc
== 0x20 || sshdr
.asc
== 0x24) {
898 switch (cmd
->cmnd
[0]) {
900 description
= "Discard failure";
904 if (cmd
->cmnd
[1] & 0x8)
905 description
= "Discard failure";
908 "Write same failure";
911 description
= "Invalid command failure";
914 action
= ACTION_FAIL
;
917 action
= ACTION_FAIL
;
919 case ABORTED_COMMAND
:
920 action
= ACTION_FAIL
;
921 if (sshdr
.asc
== 0x10) { /* DIF */
922 description
= "Target Data Integrity Failure";
927 /* If the device is in the process of becoming
928 * ready, or has a temporary blockage, retry.
930 if (sshdr
.asc
== 0x04) {
931 switch (sshdr
.ascq
) {
932 case 0x01: /* becoming ready */
933 case 0x04: /* format in progress */
934 case 0x05: /* rebuild in progress */
935 case 0x06: /* recalculation in progress */
936 case 0x07: /* operation in progress */
937 case 0x08: /* Long write in progress */
938 case 0x09: /* self test in progress */
939 case 0x14: /* space allocation in progress */
940 action
= ACTION_DELAYED_RETRY
;
943 description
= "Device not ready";
944 action
= ACTION_FAIL
;
948 description
= "Device not ready";
949 action
= ACTION_FAIL
;
952 case VOLUME_OVERFLOW
:
953 /* See SSC3rXX or current. */
954 action
= ACTION_FAIL
;
957 description
= "Unhandled sense code";
958 action
= ACTION_FAIL
;
962 description
= "Unhandled error code";
963 action
= ACTION_FAIL
;
966 if (action
!= ACTION_FAIL
&&
967 time_before(cmd
->jiffies_at_alloc
+ wait_for
, jiffies
)) {
968 action
= ACTION_FAIL
;
969 description
= "Command timed out";
974 /* Give up and fail the remainder of the request */
975 scsi_release_buffers(cmd
);
976 if (!(req
->cmd_flags
& REQ_QUIET
)) {
978 scmd_printk(KERN_INFO
, cmd
, "%s\n",
980 scsi_print_result(cmd
);
981 if (driver_byte(result
) & DRIVER_SENSE
)
982 scsi_print_sense("", cmd
);
983 scsi_print_command(cmd
);
985 if (blk_end_request_err(req
, error
))
986 scsi_requeue_command(q
, cmd
);
988 scsi_next_command(cmd
);
991 /* Unprep the request and put it back at the head of the queue.
992 * A new command will be prepared and issued.
994 scsi_release_buffers(cmd
);
995 scsi_requeue_command(q
, cmd
);
998 /* Retry the same command immediately */
999 __scsi_queue_insert(cmd
, SCSI_MLQUEUE_EH_RETRY
, 0);
1001 case ACTION_DELAYED_RETRY
:
1002 /* Retry the same command after a delay */
1003 __scsi_queue_insert(cmd
, SCSI_MLQUEUE_DEVICE_BUSY
, 0);
1008 static int scsi_init_sgtable(struct request
*req
, struct scsi_data_buffer
*sdb
,
1014 * If sg table allocation fails, requeue request later.
1016 if (unlikely(scsi_alloc_sgtable(sdb
, req
->nr_phys_segments
,
1018 return BLKPREP_DEFER
;
1024 * Next, walk the list, and fill in the addresses and sizes of
1027 count
= blk_rq_map_sg(req
->q
, req
, sdb
->table
.sgl
);
1028 BUG_ON(count
> sdb
->table
.nents
);
1029 sdb
->table
.nents
= count
;
1030 sdb
->length
= blk_rq_bytes(req
);
1035 * Function: scsi_init_io()
1037 * Purpose: SCSI I/O initialize function.
1039 * Arguments: cmd - Command descriptor we wish to initialize
1041 * Returns: 0 on success
1042 * BLKPREP_DEFER if the failure is retryable
1043 * BLKPREP_KILL if the failure is fatal
1045 int scsi_init_io(struct scsi_cmnd
*cmd
, gfp_t gfp_mask
)
1047 struct scsi_device
*sdev
= cmd
->device
;
1048 struct request
*rq
= cmd
->request
;
1050 int error
= scsi_init_sgtable(rq
, &cmd
->sdb
, gfp_mask
);
1054 if (blk_bidi_rq(rq
)) {
1055 struct scsi_data_buffer
*bidi_sdb
= kmem_cache_zalloc(
1056 scsi_sdb_cache
, GFP_ATOMIC
);
1058 error
= BLKPREP_DEFER
;
1062 rq
->next_rq
->special
= bidi_sdb
;
1063 error
= scsi_init_sgtable(rq
->next_rq
, bidi_sdb
, GFP_ATOMIC
);
1068 if (blk_integrity_rq(rq
)) {
1069 struct scsi_data_buffer
*prot_sdb
= cmd
->prot_sdb
;
1072 BUG_ON(prot_sdb
== NULL
);
1073 ivecs
= blk_rq_count_integrity_sg(rq
->q
, rq
->bio
);
1075 if (scsi_alloc_sgtable(prot_sdb
, ivecs
, gfp_mask
)) {
1076 error
= BLKPREP_DEFER
;
1080 count
= blk_rq_map_integrity_sg(rq
->q
, rq
->bio
,
1081 prot_sdb
->table
.sgl
);
1082 BUG_ON(unlikely(count
> ivecs
));
1083 BUG_ON(unlikely(count
> queue_max_integrity_segments(rq
->q
)));
1085 cmd
->prot_sdb
= prot_sdb
;
1086 cmd
->prot_sdb
->table
.nents
= count
;
1092 scsi_release_buffers(cmd
);
1093 cmd
->request
->special
= NULL
;
1094 scsi_put_command(cmd
);
1095 put_device(&sdev
->sdev_gendev
);
1098 EXPORT_SYMBOL(scsi_init_io
);
1100 static struct scsi_cmnd
*scsi_get_cmd_from_req(struct scsi_device
*sdev
,
1101 struct request
*req
)
1103 struct scsi_cmnd
*cmd
;
1105 if (!req
->special
) {
1106 /* Bail if we can't get a reference to the device */
1107 if (!get_device(&sdev
->sdev_gendev
))
1110 cmd
= scsi_get_command(sdev
, GFP_ATOMIC
);
1111 if (unlikely(!cmd
)) {
1112 put_device(&sdev
->sdev_gendev
);
1120 /* pull a tag out of the request if we have one */
1121 cmd
->tag
= req
->tag
;
1124 cmd
->cmnd
= req
->cmd
;
1125 cmd
->prot_op
= SCSI_PROT_NORMAL
;
1130 int scsi_setup_blk_pc_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1132 struct scsi_cmnd
*cmd
;
1133 int ret
= scsi_prep_state_check(sdev
, req
);
1135 if (ret
!= BLKPREP_OK
)
1138 cmd
= scsi_get_cmd_from_req(sdev
, req
);
1140 return BLKPREP_DEFER
;
1143 * BLOCK_PC requests may transfer data, in which case they must
1144 * a bio attached to them. Or they might contain a SCSI command
1145 * that does not transfer data, in which case they may optionally
1146 * submit a request without an attached bio.
1151 BUG_ON(!req
->nr_phys_segments
);
1153 ret
= scsi_init_io(cmd
, GFP_ATOMIC
);
1157 BUG_ON(blk_rq_bytes(req
));
1159 memset(&cmd
->sdb
, 0, sizeof(cmd
->sdb
));
1163 cmd
->cmd_len
= req
->cmd_len
;
1164 if (!blk_rq_bytes(req
))
1165 cmd
->sc_data_direction
= DMA_NONE
;
1166 else if (rq_data_dir(req
) == WRITE
)
1167 cmd
->sc_data_direction
= DMA_TO_DEVICE
;
1169 cmd
->sc_data_direction
= DMA_FROM_DEVICE
;
1171 cmd
->transfersize
= blk_rq_bytes(req
);
1172 cmd
->allowed
= req
->retries
;
1175 EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd
);
1178 * Setup a REQ_TYPE_FS command. These are simple read/write request
1179 * from filesystems that still need to be translated to SCSI CDBs from
1182 int scsi_setup_fs_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1184 struct scsi_cmnd
*cmd
;
1185 int ret
= scsi_prep_state_check(sdev
, req
);
1187 if (ret
!= BLKPREP_OK
)
1190 if (unlikely(sdev
->scsi_dh_data
&& sdev
->scsi_dh_data
->scsi_dh
1191 && sdev
->scsi_dh_data
->scsi_dh
->prep_fn
)) {
1192 ret
= sdev
->scsi_dh_data
->scsi_dh
->prep_fn(sdev
, req
);
1193 if (ret
!= BLKPREP_OK
)
1198 * Filesystem requests must transfer data.
1200 BUG_ON(!req
->nr_phys_segments
);
1202 cmd
= scsi_get_cmd_from_req(sdev
, req
);
1204 return BLKPREP_DEFER
;
1206 memset(cmd
->cmnd
, 0, BLK_MAX_CDB
);
1207 return scsi_init_io(cmd
, GFP_ATOMIC
);
1209 EXPORT_SYMBOL(scsi_setup_fs_cmnd
);
1211 int scsi_prep_state_check(struct scsi_device
*sdev
, struct request
*req
)
1213 int ret
= BLKPREP_OK
;
1216 * If the device is not in running state we will reject some
1219 if (unlikely(sdev
->sdev_state
!= SDEV_RUNNING
)) {
1220 switch (sdev
->sdev_state
) {
1222 case SDEV_TRANSPORT_OFFLINE
:
1224 * If the device is offline we refuse to process any
1225 * commands. The device must be brought online
1226 * before trying any recovery commands.
1228 sdev_printk(KERN_ERR
, sdev
,
1229 "rejecting I/O to offline device\n");
1234 * If the device is fully deleted, we refuse to
1235 * process any commands as well.
1237 sdev_printk(KERN_ERR
, sdev
,
1238 "rejecting I/O to dead device\n");
1243 case SDEV_CREATED_BLOCK
:
1245 * If the devices is blocked we defer normal commands.
1247 if (!(req
->cmd_flags
& REQ_PREEMPT
))
1248 ret
= BLKPREP_DEFER
;
1252 * For any other not fully online state we only allow
1253 * special commands. In particular any user initiated
1254 * command is not allowed.
1256 if (!(req
->cmd_flags
& REQ_PREEMPT
))
1263 EXPORT_SYMBOL(scsi_prep_state_check
);
1265 int scsi_prep_return(struct request_queue
*q
, struct request
*req
, int ret
)
1267 struct scsi_device
*sdev
= q
->queuedata
;
1271 req
->errors
= DID_NO_CONNECT
<< 16;
1272 /* release the command and kill it */
1274 struct scsi_cmnd
*cmd
= req
->special
;
1275 scsi_release_buffers(cmd
);
1276 scsi_put_command(cmd
);
1277 put_device(&sdev
->sdev_gendev
);
1278 req
->special
= NULL
;
1283 * If we defer, the blk_peek_request() returns NULL, but the
1284 * queue must be restarted, so we schedule a callback to happen
1287 if (sdev
->device_busy
== 0)
1288 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1291 req
->cmd_flags
|= REQ_DONTPREP
;
1296 EXPORT_SYMBOL(scsi_prep_return
);
1298 int scsi_prep_fn(struct request_queue
*q
, struct request
*req
)
1300 struct scsi_device
*sdev
= q
->queuedata
;
1301 int ret
= BLKPREP_KILL
;
1303 if (req
->cmd_type
== REQ_TYPE_BLOCK_PC
)
1304 ret
= scsi_setup_blk_pc_cmnd(sdev
, req
);
1305 return scsi_prep_return(q
, req
, ret
);
1307 EXPORT_SYMBOL(scsi_prep_fn
);
1310 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1313 * Called with the queue_lock held.
1315 static inline int scsi_dev_queue_ready(struct request_queue
*q
,
1316 struct scsi_device
*sdev
)
1318 if (sdev
->device_busy
== 0 && sdev
->device_blocked
) {
1320 * unblock after device_blocked iterates to zero
1322 if (--sdev
->device_blocked
== 0) {
1324 sdev_printk(KERN_INFO
, sdev
,
1325 "unblocking device at zero depth\n"));
1327 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1331 if (scsi_device_is_busy(sdev
))
1339 * scsi_target_queue_ready: checks if there we can send commands to target
1340 * @sdev: scsi device on starget to check.
1342 * Called with the host lock held.
1344 static inline int scsi_target_queue_ready(struct Scsi_Host
*shost
,
1345 struct scsi_device
*sdev
)
1347 struct scsi_target
*starget
= scsi_target(sdev
);
1349 if (starget
->single_lun
) {
1350 if (starget
->starget_sdev_user
&&
1351 starget
->starget_sdev_user
!= sdev
)
1353 starget
->starget_sdev_user
= sdev
;
1356 if (starget
->target_busy
== 0 && starget
->target_blocked
) {
1358 * unblock after target_blocked iterates to zero
1360 if (--starget
->target_blocked
== 0) {
1361 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO
, starget
,
1362 "unblocking target at zero depth\n"));
1367 if (scsi_target_is_busy(starget
)) {
1368 list_move_tail(&sdev
->starved_entry
, &shost
->starved_list
);
1376 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1377 * return 0. We must end up running the queue again whenever 0 is
1378 * returned, else IO can hang.
1380 * Called with host_lock held.
1382 static inline int scsi_host_queue_ready(struct request_queue
*q
,
1383 struct Scsi_Host
*shost
,
1384 struct scsi_device
*sdev
)
1386 if (scsi_host_in_recovery(shost
))
1388 if (shost
->host_busy
== 0 && shost
->host_blocked
) {
1390 * unblock after host_blocked iterates to zero
1392 if (--shost
->host_blocked
== 0) {
1394 printk("scsi%d unblocking host at zero depth\n",
1400 if (scsi_host_is_busy(shost
)) {
1401 if (list_empty(&sdev
->starved_entry
))
1402 list_add_tail(&sdev
->starved_entry
, &shost
->starved_list
);
1406 /* We're OK to process the command, so we can't be starved */
1407 if (!list_empty(&sdev
->starved_entry
))
1408 list_del_init(&sdev
->starved_entry
);
1414 * Busy state exporting function for request stacking drivers.
1416 * For efficiency, no lock is taken to check the busy state of
1417 * shost/starget/sdev, since the returned value is not guaranteed and
1418 * may be changed after request stacking drivers call the function,
1419 * regardless of taking lock or not.
1421 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1422 * needs to return 'not busy'. Otherwise, request stacking drivers
1423 * may hold requests forever.
1425 static int scsi_lld_busy(struct request_queue
*q
)
1427 struct scsi_device
*sdev
= q
->queuedata
;
1428 struct Scsi_Host
*shost
;
1430 if (blk_queue_dying(q
))
1436 * Ignore host/starget busy state.
1437 * Since block layer does not have a concept of fairness across
1438 * multiple queues, congestion of host/starget needs to be handled
1441 if (scsi_host_in_recovery(shost
) || scsi_device_is_busy(sdev
))
1448 * Kill a request for a dead device
1450 static void scsi_kill_request(struct request
*req
, struct request_queue
*q
)
1452 struct scsi_cmnd
*cmd
= req
->special
;
1453 struct scsi_device
*sdev
;
1454 struct scsi_target
*starget
;
1455 struct Scsi_Host
*shost
;
1457 blk_start_request(req
);
1459 scmd_printk(KERN_INFO
, cmd
, "killing request\n");
1462 starget
= scsi_target(sdev
);
1464 scsi_init_cmd_errh(cmd
);
1465 cmd
->result
= DID_NO_CONNECT
<< 16;
1466 atomic_inc(&cmd
->device
->iorequest_cnt
);
1469 * SCSI request completion path will do scsi_device_unbusy(),
1470 * bump busy counts. To bump the counters, we need to dance
1471 * with the locks as normal issue path does.
1473 sdev
->device_busy
++;
1474 spin_unlock(sdev
->request_queue
->queue_lock
);
1475 spin_lock(shost
->host_lock
);
1477 starget
->target_busy
++;
1478 spin_unlock(shost
->host_lock
);
1479 spin_lock(sdev
->request_queue
->queue_lock
);
1481 blk_complete_request(req
);
1484 static void scsi_softirq_done(struct request
*rq
)
1486 struct scsi_cmnd
*cmd
= rq
->special
;
1487 unsigned long wait_for
= (cmd
->allowed
+ 1) * rq
->timeout
;
1490 INIT_LIST_HEAD(&cmd
->eh_entry
);
1492 atomic_inc(&cmd
->device
->iodone_cnt
);
1494 atomic_inc(&cmd
->device
->ioerr_cnt
);
1496 disposition
= scsi_decide_disposition(cmd
);
1497 if (disposition
!= SUCCESS
&&
1498 time_before(cmd
->jiffies_at_alloc
+ wait_for
, jiffies
)) {
1499 sdev_printk(KERN_ERR
, cmd
->device
,
1500 "timing out command, waited %lus\n",
1502 disposition
= SUCCESS
;
1505 scsi_log_completion(cmd
, disposition
);
1507 switch (disposition
) {
1509 scsi_finish_command(cmd
);
1512 scsi_queue_insert(cmd
, SCSI_MLQUEUE_EH_RETRY
);
1514 case ADD_TO_MLQUEUE
:
1515 scsi_queue_insert(cmd
, SCSI_MLQUEUE_DEVICE_BUSY
);
1518 if (!scsi_eh_scmd_add(cmd
, 0))
1519 scsi_finish_command(cmd
);
1524 * Function: scsi_request_fn()
1526 * Purpose: Main strategy routine for SCSI.
1528 * Arguments: q - Pointer to actual queue.
1532 * Lock status: IO request lock assumed to be held when called.
1534 static void scsi_request_fn(struct request_queue
*q
)
1535 __releases(q
->queue_lock
)
1536 __acquires(q
->queue_lock
)
1538 struct scsi_device
*sdev
= q
->queuedata
;
1539 struct Scsi_Host
*shost
;
1540 struct scsi_cmnd
*cmd
;
1541 struct request
*req
;
1544 * To start with, we keep looping until the queue is empty, or until
1545 * the host is no longer able to accept any more requests.
1551 * get next queueable request. We do this early to make sure
1552 * that the request is fully prepared even if we cannot
1555 req
= blk_peek_request(q
);
1556 if (!req
|| !scsi_dev_queue_ready(q
, sdev
))
1559 if (unlikely(!scsi_device_online(sdev
))) {
1560 sdev_printk(KERN_ERR
, sdev
,
1561 "rejecting I/O to offline device\n");
1562 scsi_kill_request(req
, q
);
1568 * Remove the request from the request list.
1570 if (!(blk_queue_tagged(q
) && !blk_queue_start_tag(q
, req
)))
1571 blk_start_request(req
);
1572 sdev
->device_busy
++;
1574 spin_unlock(q
->queue_lock
);
1576 if (unlikely(cmd
== NULL
)) {
1577 printk(KERN_CRIT
"impossible request in %s.\n"
1578 "please mail a stack trace to "
1579 "linux-scsi@vger.kernel.org\n",
1581 blk_dump_rq_flags(req
, "foo");
1584 spin_lock(shost
->host_lock
);
1587 * We hit this when the driver is using a host wide
1588 * tag map. For device level tag maps the queue_depth check
1589 * in the device ready fn would prevent us from trying
1590 * to allocate a tag. Since the map is a shared host resource
1591 * we add the dev to the starved list so it eventually gets
1592 * a run when a tag is freed.
1594 if (blk_queue_tagged(q
) && !blk_rq_tagged(req
)) {
1595 if (list_empty(&sdev
->starved_entry
))
1596 list_add_tail(&sdev
->starved_entry
,
1597 &shost
->starved_list
);
1601 if (!scsi_target_queue_ready(shost
, sdev
))
1604 if (!scsi_host_queue_ready(q
, shost
, sdev
))
1607 scsi_target(sdev
)->target_busy
++;
1611 * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will
1612 * take the lock again.
1614 spin_unlock_irq(shost
->host_lock
);
1617 * Finally, initialize any error handling parameters, and set up
1618 * the timers for timeouts.
1620 scsi_init_cmd_errh(cmd
);
1623 * Dispatch the command to the low-level driver.
1625 rtn
= scsi_dispatch_cmd(cmd
);
1626 spin_lock_irq(q
->queue_lock
);
1634 spin_unlock_irq(shost
->host_lock
);
1637 * lock q, handle tag, requeue req, and decrement device_busy. We
1638 * must return with queue_lock held.
1640 * Decrementing device_busy without checking it is OK, as all such
1641 * cases (host limits or settings) should run the queue at some
1644 spin_lock_irq(q
->queue_lock
);
1645 blk_requeue_request(q
, req
);
1646 sdev
->device_busy
--;
1648 if (sdev
->device_busy
== 0)
1649 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1652 u64
scsi_calculate_bounce_limit(struct Scsi_Host
*shost
)
1654 struct device
*host_dev
;
1655 u64 bounce_limit
= 0xffffffff;
1657 if (shost
->unchecked_isa_dma
)
1658 return BLK_BOUNCE_ISA
;
1660 * Platforms with virtual-DMA translation
1661 * hardware have no practical limit.
1663 if (!PCI_DMA_BUS_IS_PHYS
)
1664 return BLK_BOUNCE_ANY
;
1666 host_dev
= scsi_get_device(shost
);
1667 if (host_dev
&& host_dev
->dma_mask
)
1668 bounce_limit
= (u64
)dma_max_pfn(host_dev
) << PAGE_SHIFT
;
1670 return bounce_limit
;
1672 EXPORT_SYMBOL(scsi_calculate_bounce_limit
);
1674 struct request_queue
*__scsi_alloc_queue(struct Scsi_Host
*shost
,
1675 request_fn_proc
*request_fn
)
1677 struct request_queue
*q
;
1678 struct device
*dev
= shost
->dma_dev
;
1680 q
= blk_init_queue(request_fn
, NULL
);
1685 * this limit is imposed by hardware restrictions
1687 blk_queue_max_segments(q
, min_t(unsigned short, shost
->sg_tablesize
,
1688 SCSI_MAX_SG_CHAIN_SEGMENTS
));
1690 if (scsi_host_prot_dma(shost
)) {
1691 shost
->sg_prot_tablesize
=
1692 min_not_zero(shost
->sg_prot_tablesize
,
1693 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS
);
1694 BUG_ON(shost
->sg_prot_tablesize
< shost
->sg_tablesize
);
1695 blk_queue_max_integrity_segments(q
, shost
->sg_prot_tablesize
);
1698 blk_queue_max_hw_sectors(q
, shost
->max_sectors
);
1699 blk_queue_bounce_limit(q
, scsi_calculate_bounce_limit(shost
));
1700 blk_queue_segment_boundary(q
, shost
->dma_boundary
);
1701 dma_set_seg_boundary(dev
, shost
->dma_boundary
);
1703 blk_queue_max_segment_size(q
, dma_get_max_seg_size(dev
));
1705 if (!shost
->use_clustering
)
1706 q
->limits
.cluster
= 0;
1709 * set a reasonable default alignment on word boundaries: the
1710 * host and device may alter it using
1711 * blk_queue_update_dma_alignment() later.
1713 blk_queue_dma_alignment(q
, 0x03);
1717 EXPORT_SYMBOL(__scsi_alloc_queue
);
1719 struct request_queue
*scsi_alloc_queue(struct scsi_device
*sdev
)
1721 struct request_queue
*q
;
1723 q
= __scsi_alloc_queue(sdev
->host
, scsi_request_fn
);
1727 blk_queue_prep_rq(q
, scsi_prep_fn
);
1728 blk_queue_softirq_done(q
, scsi_softirq_done
);
1729 blk_queue_rq_timed_out(q
, scsi_times_out
);
1730 blk_queue_lld_busy(q
, scsi_lld_busy
);
1735 * Function: scsi_block_requests()
1737 * Purpose: Utility function used by low-level drivers to prevent further
1738 * commands from being queued to the device.
1740 * Arguments: shost - Host in question
1744 * Lock status: No locks are assumed held.
1746 * Notes: There is no timer nor any other means by which the requests
1747 * get unblocked other than the low-level driver calling
1748 * scsi_unblock_requests().
1750 void scsi_block_requests(struct Scsi_Host
*shost
)
1752 shost
->host_self_blocked
= 1;
1754 EXPORT_SYMBOL(scsi_block_requests
);
1757 * Function: scsi_unblock_requests()
1759 * Purpose: Utility function used by low-level drivers to allow further
1760 * commands from being queued to the device.
1762 * Arguments: shost - Host in question
1766 * Lock status: No locks are assumed held.
1768 * Notes: There is no timer nor any other means by which the requests
1769 * get unblocked other than the low-level driver calling
1770 * scsi_unblock_requests().
1772 * This is done as an API function so that changes to the
1773 * internals of the scsi mid-layer won't require wholesale
1774 * changes to drivers that use this feature.
1776 void scsi_unblock_requests(struct Scsi_Host
*shost
)
1778 shost
->host_self_blocked
= 0;
1779 scsi_run_host_queues(shost
);
1781 EXPORT_SYMBOL(scsi_unblock_requests
);
1783 int __init
scsi_init_queue(void)
1787 scsi_sdb_cache
= kmem_cache_create("scsi_data_buffer",
1788 sizeof(struct scsi_data_buffer
),
1790 if (!scsi_sdb_cache
) {
1791 printk(KERN_ERR
"SCSI: can't init scsi sdb cache\n");
1795 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
1796 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
1797 int size
= sgp
->size
* sizeof(struct scatterlist
);
1799 sgp
->slab
= kmem_cache_create(sgp
->name
, size
, 0,
1800 SLAB_HWCACHE_ALIGN
, NULL
);
1802 printk(KERN_ERR
"SCSI: can't init sg slab %s\n",
1807 sgp
->pool
= mempool_create_slab_pool(SG_MEMPOOL_SIZE
,
1810 printk(KERN_ERR
"SCSI: can't init sg mempool %s\n",
1819 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
1820 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
1822 mempool_destroy(sgp
->pool
);
1824 kmem_cache_destroy(sgp
->slab
);
1826 kmem_cache_destroy(scsi_sdb_cache
);
1831 void scsi_exit_queue(void)
1835 kmem_cache_destroy(scsi_sdb_cache
);
1837 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
1838 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
1839 mempool_destroy(sgp
->pool
);
1840 kmem_cache_destroy(sgp
->slab
);
1845 * scsi_mode_select - issue a mode select
1846 * @sdev: SCSI device to be queried
1847 * @pf: Page format bit (1 == standard, 0 == vendor specific)
1848 * @sp: Save page bit (0 == don't save, 1 == save)
1849 * @modepage: mode page being requested
1850 * @buffer: request buffer (may not be smaller than eight bytes)
1851 * @len: length of request buffer.
1852 * @timeout: command timeout
1853 * @retries: number of retries before failing
1854 * @data: returns a structure abstracting the mode header data
1855 * @sshdr: place to put sense data (or NULL if no sense to be collected).
1856 * must be SCSI_SENSE_BUFFERSIZE big.
1858 * Returns zero if successful; negative error number or scsi
1863 scsi_mode_select(struct scsi_device
*sdev
, int pf
, int sp
, int modepage
,
1864 unsigned char *buffer
, int len
, int timeout
, int retries
,
1865 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
1867 unsigned char cmd
[10];
1868 unsigned char *real_buffer
;
1871 memset(cmd
, 0, sizeof(cmd
));
1872 cmd
[1] = (pf
? 0x10 : 0) | (sp
? 0x01 : 0);
1874 if (sdev
->use_10_for_ms
) {
1877 real_buffer
= kmalloc(8 + len
, GFP_KERNEL
);
1880 memcpy(real_buffer
+ 8, buffer
, len
);
1884 real_buffer
[2] = data
->medium_type
;
1885 real_buffer
[3] = data
->device_specific
;
1886 real_buffer
[4] = data
->longlba
? 0x01 : 0;
1888 real_buffer
[6] = data
->block_descriptor_length
>> 8;
1889 real_buffer
[7] = data
->block_descriptor_length
;
1891 cmd
[0] = MODE_SELECT_10
;
1895 if (len
> 255 || data
->block_descriptor_length
> 255 ||
1899 real_buffer
= kmalloc(4 + len
, GFP_KERNEL
);
1902 memcpy(real_buffer
+ 4, buffer
, len
);
1905 real_buffer
[1] = data
->medium_type
;
1906 real_buffer
[2] = data
->device_specific
;
1907 real_buffer
[3] = data
->block_descriptor_length
;
1910 cmd
[0] = MODE_SELECT
;
1914 ret
= scsi_execute_req(sdev
, cmd
, DMA_TO_DEVICE
, real_buffer
, len
,
1915 sshdr
, timeout
, retries
, NULL
);
1919 EXPORT_SYMBOL_GPL(scsi_mode_select
);
1922 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
1923 * @sdev: SCSI device to be queried
1924 * @dbd: set if mode sense will allow block descriptors to be returned
1925 * @modepage: mode page being requested
1926 * @buffer: request buffer (may not be smaller than eight bytes)
1927 * @len: length of request buffer.
1928 * @timeout: command timeout
1929 * @retries: number of retries before failing
1930 * @data: returns a structure abstracting the mode header data
1931 * @sshdr: place to put sense data (or NULL if no sense to be collected).
1932 * must be SCSI_SENSE_BUFFERSIZE big.
1934 * Returns zero if unsuccessful, or the header offset (either 4
1935 * or 8 depending on whether a six or ten byte command was
1936 * issued) if successful.
1939 scsi_mode_sense(struct scsi_device
*sdev
, int dbd
, int modepage
,
1940 unsigned char *buffer
, int len
, int timeout
, int retries
,
1941 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
1943 unsigned char cmd
[12];
1947 struct scsi_sense_hdr my_sshdr
;
1949 memset(data
, 0, sizeof(*data
));
1950 memset(&cmd
[0], 0, 12);
1951 cmd
[1] = dbd
& 0x18; /* allows DBD and LLBA bits */
1954 /* caller might not be interested in sense, but we need it */
1959 use_10_for_ms
= sdev
->use_10_for_ms
;
1961 if (use_10_for_ms
) {
1965 cmd
[0] = MODE_SENSE_10
;
1972 cmd
[0] = MODE_SENSE
;
1977 memset(buffer
, 0, len
);
1979 result
= scsi_execute_req(sdev
, cmd
, DMA_FROM_DEVICE
, buffer
, len
,
1980 sshdr
, timeout
, retries
, NULL
);
1982 /* This code looks awful: what it's doing is making sure an
1983 * ILLEGAL REQUEST sense return identifies the actual command
1984 * byte as the problem. MODE_SENSE commands can return
1985 * ILLEGAL REQUEST if the code page isn't supported */
1987 if (use_10_for_ms
&& !scsi_status_is_good(result
) &&
1988 (driver_byte(result
) & DRIVER_SENSE
)) {
1989 if (scsi_sense_valid(sshdr
)) {
1990 if ((sshdr
->sense_key
== ILLEGAL_REQUEST
) &&
1991 (sshdr
->asc
== 0x20) && (sshdr
->ascq
== 0)) {
1993 * Invalid command operation code
1995 sdev
->use_10_for_ms
= 0;
2001 if(scsi_status_is_good(result
)) {
2002 if (unlikely(buffer
[0] == 0x86 && buffer
[1] == 0x0b &&
2003 (modepage
== 6 || modepage
== 8))) {
2004 /* Initio breakage? */
2007 data
->medium_type
= 0;
2008 data
->device_specific
= 0;
2010 data
->block_descriptor_length
= 0;
2011 } else if(use_10_for_ms
) {
2012 data
->length
= buffer
[0]*256 + buffer
[1] + 2;
2013 data
->medium_type
= buffer
[2];
2014 data
->device_specific
= buffer
[3];
2015 data
->longlba
= buffer
[4] & 0x01;
2016 data
->block_descriptor_length
= buffer
[6]*256
2019 data
->length
= buffer
[0] + 1;
2020 data
->medium_type
= buffer
[1];
2021 data
->device_specific
= buffer
[2];
2022 data
->block_descriptor_length
= buffer
[3];
2024 data
->header_length
= header_length
;
2029 EXPORT_SYMBOL(scsi_mode_sense
);
2032 * scsi_test_unit_ready - test if unit is ready
2033 * @sdev: scsi device to change the state of.
2034 * @timeout: command timeout
2035 * @retries: number of retries before failing
2036 * @sshdr_external: Optional pointer to struct scsi_sense_hdr for
2037 * returning sense. Make sure that this is cleared before passing
2040 * Returns zero if unsuccessful or an error if TUR failed. For
2041 * removable media, UNIT_ATTENTION sets ->changed flag.
2044 scsi_test_unit_ready(struct scsi_device
*sdev
, int timeout
, int retries
,
2045 struct scsi_sense_hdr
*sshdr_external
)
2048 TEST_UNIT_READY
, 0, 0, 0, 0, 0,
2050 struct scsi_sense_hdr
*sshdr
;
2053 if (!sshdr_external
)
2054 sshdr
= kzalloc(sizeof(*sshdr
), GFP_KERNEL
);
2056 sshdr
= sshdr_external
;
2058 /* try to eat the UNIT_ATTENTION if there are enough retries */
2060 result
= scsi_execute_req(sdev
, cmd
, DMA_NONE
, NULL
, 0, sshdr
,
2061 timeout
, retries
, NULL
);
2062 if (sdev
->removable
&& scsi_sense_valid(sshdr
) &&
2063 sshdr
->sense_key
== UNIT_ATTENTION
)
2065 } while (scsi_sense_valid(sshdr
) &&
2066 sshdr
->sense_key
== UNIT_ATTENTION
&& --retries
);
2068 if (!sshdr_external
)
2072 EXPORT_SYMBOL(scsi_test_unit_ready
);
2075 * scsi_device_set_state - Take the given device through the device state model.
2076 * @sdev: scsi device to change the state of.
2077 * @state: state to change to.
2079 * Returns zero if unsuccessful or an error if the requested
2080 * transition is illegal.
2083 scsi_device_set_state(struct scsi_device
*sdev
, enum scsi_device_state state
)
2085 enum scsi_device_state oldstate
= sdev
->sdev_state
;
2087 if (state
== oldstate
)
2093 case SDEV_CREATED_BLOCK
:
2104 case SDEV_TRANSPORT_OFFLINE
:
2117 case SDEV_TRANSPORT_OFFLINE
:
2125 case SDEV_TRANSPORT_OFFLINE
:
2140 case SDEV_CREATED_BLOCK
:
2147 case SDEV_CREATED_BLOCK
:
2162 case SDEV_TRANSPORT_OFFLINE
:
2175 case SDEV_TRANSPORT_OFFLINE
:
2177 case SDEV_CREATED_BLOCK
:
2185 sdev
->sdev_state
= state
;
2189 SCSI_LOG_ERROR_RECOVERY(1,
2190 sdev_printk(KERN_ERR
, sdev
,
2191 "Illegal state transition %s->%s\n",
2192 scsi_device_state_name(oldstate
),
2193 scsi_device_state_name(state
))
2197 EXPORT_SYMBOL(scsi_device_set_state
);
2200 * sdev_evt_emit - emit a single SCSI device uevent
2201 * @sdev: associated SCSI device
2202 * @evt: event to emit
2204 * Send a single uevent (scsi_event) to the associated scsi_device.
2206 static void scsi_evt_emit(struct scsi_device
*sdev
, struct scsi_event
*evt
)
2211 switch (evt
->evt_type
) {
2212 case SDEV_EVT_MEDIA_CHANGE
:
2213 envp
[idx
++] = "SDEV_MEDIA_CHANGE=1";
2215 case SDEV_EVT_INQUIRY_CHANGE_REPORTED
:
2216 envp
[idx
++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2218 case SDEV_EVT_CAPACITY_CHANGE_REPORTED
:
2219 envp
[idx
++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2221 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED
:
2222 envp
[idx
++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2224 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED
:
2225 envp
[idx
++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2227 case SDEV_EVT_LUN_CHANGE_REPORTED
:
2228 envp
[idx
++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2237 kobject_uevent_env(&sdev
->sdev_gendev
.kobj
, KOBJ_CHANGE
, envp
);
2241 * sdev_evt_thread - send a uevent for each scsi event
2242 * @work: work struct for scsi_device
2244 * Dispatch queued events to their associated scsi_device kobjects
2247 void scsi_evt_thread(struct work_struct
*work
)
2249 struct scsi_device
*sdev
;
2250 enum scsi_device_event evt_type
;
2251 LIST_HEAD(event_list
);
2253 sdev
= container_of(work
, struct scsi_device
, event_work
);
2255 for (evt_type
= SDEV_EVT_FIRST
; evt_type
<= SDEV_EVT_LAST
; evt_type
++)
2256 if (test_and_clear_bit(evt_type
, sdev
->pending_events
))
2257 sdev_evt_send_simple(sdev
, evt_type
, GFP_KERNEL
);
2260 struct scsi_event
*evt
;
2261 struct list_head
*this, *tmp
;
2262 unsigned long flags
;
2264 spin_lock_irqsave(&sdev
->list_lock
, flags
);
2265 list_splice_init(&sdev
->event_list
, &event_list
);
2266 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
2268 if (list_empty(&event_list
))
2271 list_for_each_safe(this, tmp
, &event_list
) {
2272 evt
= list_entry(this, struct scsi_event
, node
);
2273 list_del(&evt
->node
);
2274 scsi_evt_emit(sdev
, evt
);
2281 * sdev_evt_send - send asserted event to uevent thread
2282 * @sdev: scsi_device event occurred on
2283 * @evt: event to send
2285 * Assert scsi device event asynchronously.
2287 void sdev_evt_send(struct scsi_device
*sdev
, struct scsi_event
*evt
)
2289 unsigned long flags
;
2292 /* FIXME: currently this check eliminates all media change events
2293 * for polled devices. Need to update to discriminate between AN
2294 * and polled events */
2295 if (!test_bit(evt
->evt_type
, sdev
->supported_events
)) {
2301 spin_lock_irqsave(&sdev
->list_lock
, flags
);
2302 list_add_tail(&evt
->node
, &sdev
->event_list
);
2303 schedule_work(&sdev
->event_work
);
2304 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
2306 EXPORT_SYMBOL_GPL(sdev_evt_send
);
2309 * sdev_evt_alloc - allocate a new scsi event
2310 * @evt_type: type of event to allocate
2311 * @gfpflags: GFP flags for allocation
2313 * Allocates and returns a new scsi_event.
2315 struct scsi_event
*sdev_evt_alloc(enum scsi_device_event evt_type
,
2318 struct scsi_event
*evt
= kzalloc(sizeof(struct scsi_event
), gfpflags
);
2322 evt
->evt_type
= evt_type
;
2323 INIT_LIST_HEAD(&evt
->node
);
2325 /* evt_type-specific initialization, if any */
2327 case SDEV_EVT_MEDIA_CHANGE
:
2328 case SDEV_EVT_INQUIRY_CHANGE_REPORTED
:
2329 case SDEV_EVT_CAPACITY_CHANGE_REPORTED
:
2330 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED
:
2331 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED
:
2332 case SDEV_EVT_LUN_CHANGE_REPORTED
:
2340 EXPORT_SYMBOL_GPL(sdev_evt_alloc
);
2343 * sdev_evt_send_simple - send asserted event to uevent thread
2344 * @sdev: scsi_device event occurred on
2345 * @evt_type: type of event to send
2346 * @gfpflags: GFP flags for allocation
2348 * Assert scsi device event asynchronously, given an event type.
2350 void sdev_evt_send_simple(struct scsi_device
*sdev
,
2351 enum scsi_device_event evt_type
, gfp_t gfpflags
)
2353 struct scsi_event
*evt
= sdev_evt_alloc(evt_type
, gfpflags
);
2355 sdev_printk(KERN_ERR
, sdev
, "event %d eaten due to OOM\n",
2360 sdev_evt_send(sdev
, evt
);
2362 EXPORT_SYMBOL_GPL(sdev_evt_send_simple
);
2365 * scsi_device_quiesce - Block user issued commands.
2366 * @sdev: scsi device to quiesce.
2368 * This works by trying to transition to the SDEV_QUIESCE state
2369 * (which must be a legal transition). When the device is in this
2370 * state, only special requests will be accepted, all others will
2371 * be deferred. Since special requests may also be requeued requests,
2372 * a successful return doesn't guarantee the device will be
2373 * totally quiescent.
2375 * Must be called with user context, may sleep.
2377 * Returns zero if unsuccessful or an error if not.
2380 scsi_device_quiesce(struct scsi_device
*sdev
)
2382 int err
= scsi_device_set_state(sdev
, SDEV_QUIESCE
);
2386 scsi_run_queue(sdev
->request_queue
);
2387 while (sdev
->device_busy
) {
2388 msleep_interruptible(200);
2389 scsi_run_queue(sdev
->request_queue
);
2393 EXPORT_SYMBOL(scsi_device_quiesce
);
2396 * scsi_device_resume - Restart user issued commands to a quiesced device.
2397 * @sdev: scsi device to resume.
2399 * Moves the device from quiesced back to running and restarts the
2402 * Must be called with user context, may sleep.
2404 void scsi_device_resume(struct scsi_device
*sdev
)
2406 /* check if the device state was mutated prior to resume, and if
2407 * so assume the state is being managed elsewhere (for example
2408 * device deleted during suspend)
2410 if (sdev
->sdev_state
!= SDEV_QUIESCE
||
2411 scsi_device_set_state(sdev
, SDEV_RUNNING
))
2413 scsi_run_queue(sdev
->request_queue
);
2415 EXPORT_SYMBOL(scsi_device_resume
);
2418 device_quiesce_fn(struct scsi_device
*sdev
, void *data
)
2420 scsi_device_quiesce(sdev
);
2424 scsi_target_quiesce(struct scsi_target
*starget
)
2426 starget_for_each_device(starget
, NULL
, device_quiesce_fn
);
2428 EXPORT_SYMBOL(scsi_target_quiesce
);
2431 device_resume_fn(struct scsi_device
*sdev
, void *data
)
2433 scsi_device_resume(sdev
);
2437 scsi_target_resume(struct scsi_target
*starget
)
2439 starget_for_each_device(starget
, NULL
, device_resume_fn
);
2441 EXPORT_SYMBOL(scsi_target_resume
);
2444 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state
2445 * @sdev: device to block
2447 * Block request made by scsi lld's to temporarily stop all
2448 * scsi commands on the specified device. Called from interrupt
2449 * or normal process context.
2451 * Returns zero if successful or error if not
2454 * This routine transitions the device to the SDEV_BLOCK state
2455 * (which must be a legal transition). When the device is in this
2456 * state, all commands are deferred until the scsi lld reenables
2457 * the device with scsi_device_unblock or device_block_tmo fires.
2460 scsi_internal_device_block(struct scsi_device
*sdev
)
2462 struct request_queue
*q
= sdev
->request_queue
;
2463 unsigned long flags
;
2466 err
= scsi_device_set_state(sdev
, SDEV_BLOCK
);
2468 err
= scsi_device_set_state(sdev
, SDEV_CREATED_BLOCK
);
2475 * The device has transitioned to SDEV_BLOCK. Stop the
2476 * block layer from calling the midlayer with this device's
2479 spin_lock_irqsave(q
->queue_lock
, flags
);
2481 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2485 EXPORT_SYMBOL_GPL(scsi_internal_device_block
);
2488 * scsi_internal_device_unblock - resume a device after a block request
2489 * @sdev: device to resume
2490 * @new_state: state to set devices to after unblocking
2492 * Called by scsi lld's or the midlayer to restart the device queue
2493 * for the previously suspended scsi device. Called from interrupt or
2494 * normal process context.
2496 * Returns zero if successful or error if not.
2499 * This routine transitions the device to the SDEV_RUNNING state
2500 * or to one of the offline states (which must be a legal transition)
2501 * allowing the midlayer to goose the queue for this device.
2504 scsi_internal_device_unblock(struct scsi_device
*sdev
,
2505 enum scsi_device_state new_state
)
2507 struct request_queue
*q
= sdev
->request_queue
;
2508 unsigned long flags
;
2511 * Try to transition the scsi device to SDEV_RUNNING or one of the
2512 * offlined states and goose the device queue if successful.
2514 if ((sdev
->sdev_state
== SDEV_BLOCK
) ||
2515 (sdev
->sdev_state
== SDEV_TRANSPORT_OFFLINE
))
2516 sdev
->sdev_state
= new_state
;
2517 else if (sdev
->sdev_state
== SDEV_CREATED_BLOCK
) {
2518 if (new_state
== SDEV_TRANSPORT_OFFLINE
||
2519 new_state
== SDEV_OFFLINE
)
2520 sdev
->sdev_state
= new_state
;
2522 sdev
->sdev_state
= SDEV_CREATED
;
2523 } else if (sdev
->sdev_state
!= SDEV_CANCEL
&&
2524 sdev
->sdev_state
!= SDEV_OFFLINE
)
2527 spin_lock_irqsave(q
->queue_lock
, flags
);
2529 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2533 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock
);
2536 device_block(struct scsi_device
*sdev
, void *data
)
2538 scsi_internal_device_block(sdev
);
2542 target_block(struct device
*dev
, void *data
)
2544 if (scsi_is_target_device(dev
))
2545 starget_for_each_device(to_scsi_target(dev
), NULL
,
2551 scsi_target_block(struct device
*dev
)
2553 if (scsi_is_target_device(dev
))
2554 starget_for_each_device(to_scsi_target(dev
), NULL
,
2557 device_for_each_child(dev
, NULL
, target_block
);
2559 EXPORT_SYMBOL_GPL(scsi_target_block
);
2562 device_unblock(struct scsi_device
*sdev
, void *data
)
2564 scsi_internal_device_unblock(sdev
, *(enum scsi_device_state
*)data
);
2568 target_unblock(struct device
*dev
, void *data
)
2570 if (scsi_is_target_device(dev
))
2571 starget_for_each_device(to_scsi_target(dev
), data
,
2577 scsi_target_unblock(struct device
*dev
, enum scsi_device_state new_state
)
2579 if (scsi_is_target_device(dev
))
2580 starget_for_each_device(to_scsi_target(dev
), &new_state
,
2583 device_for_each_child(dev
, &new_state
, target_unblock
);
2585 EXPORT_SYMBOL_GPL(scsi_target_unblock
);
2588 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
2589 * @sgl: scatter-gather list
2590 * @sg_count: number of segments in sg
2591 * @offset: offset in bytes into sg, on return offset into the mapped area
2592 * @len: bytes to map, on return number of bytes mapped
2594 * Returns virtual address of the start of the mapped page
2596 void *scsi_kmap_atomic_sg(struct scatterlist
*sgl
, int sg_count
,
2597 size_t *offset
, size_t *len
)
2600 size_t sg_len
= 0, len_complete
= 0;
2601 struct scatterlist
*sg
;
2604 WARN_ON(!irqs_disabled());
2606 for_each_sg(sgl
, sg
, sg_count
, i
) {
2607 len_complete
= sg_len
; /* Complete sg-entries */
2608 sg_len
+= sg
->length
;
2609 if (sg_len
> *offset
)
2613 if (unlikely(i
== sg_count
)) {
2614 printk(KERN_ERR
"%s: Bytes in sg: %zu, requested offset %zu, "
2616 __func__
, sg_len
, *offset
, sg_count
);
2621 /* Offset starting from the beginning of first page in this sg-entry */
2622 *offset
= *offset
- len_complete
+ sg
->offset
;
2624 /* Assumption: contiguous pages can be accessed as "page + i" */
2625 page
= nth_page(sg_page(sg
), (*offset
>> PAGE_SHIFT
));
2626 *offset
&= ~PAGE_MASK
;
2628 /* Bytes in this sg-entry from *offset to the end of the page */
2629 sg_len
= PAGE_SIZE
- *offset
;
2633 return kmap_atomic(page
);
2635 EXPORT_SYMBOL(scsi_kmap_atomic_sg
);
2638 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
2639 * @virt: virtual address to be unmapped
2641 void scsi_kunmap_atomic_sg(void *virt
)
2643 kunmap_atomic(virt
);
2645 EXPORT_SYMBOL(scsi_kunmap_atomic_sg
);
2647 void sdev_disable_disk_events(struct scsi_device
*sdev
)
2649 atomic_inc(&sdev
->disk_events_disable_depth
);
2651 EXPORT_SYMBOL(sdev_disable_disk_events
);
2653 void sdev_enable_disk_events(struct scsi_device
*sdev
)
2655 if (WARN_ON_ONCE(atomic_read(&sdev
->disk_events_disable_depth
) <= 0))
2657 atomic_dec(&sdev
->disk_events_disable_depth
);
2659 EXPORT_SYMBOL(sdev_enable_disk_events
);