2 * scsi_lib.c Copyright (C) 1999 Eric Youngdale
4 * SCSI queueing library.
5 * Initial versions: Eric Youngdale (eric@andante.org).
6 * Based upon conversations with large numbers
7 * of people at Linux Expo.
10 #include <linux/bio.h>
11 #include <linux/bitops.h>
12 #include <linux/blkdev.h>
13 #include <linux/completion.h>
14 #include <linux/kernel.h>
15 #include <linux/export.h>
16 #include <linux/mempool.h>
17 #include <linux/slab.h>
18 #include <linux/init.h>
19 #include <linux/pci.h>
20 #include <linux/delay.h>
21 #include <linux/hardirq.h>
22 #include <linux/scatterlist.h>
24 #include <scsi/scsi.h>
25 #include <scsi/scsi_cmnd.h>
26 #include <scsi/scsi_dbg.h>
27 #include <scsi/scsi_device.h>
28 #include <scsi/scsi_driver.h>
29 #include <scsi/scsi_eh.h>
30 #include <scsi/scsi_host.h>
32 #include "scsi_priv.h"
33 #include "scsi_logging.h"
36 #define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools)
37 #define SG_MEMPOOL_SIZE 2
39 struct scsi_host_sg_pool
{
42 struct kmem_cache
*slab
;
46 #define SP(x) { x, "sgpool-" __stringify(x) }
47 #if (SCSI_MAX_SG_SEGMENTS < 32)
48 #error SCSI_MAX_SG_SEGMENTS is too small (must be 32 or greater)
50 static struct scsi_host_sg_pool scsi_sg_pools
[] = {
53 #if (SCSI_MAX_SG_SEGMENTS > 32)
55 #if (SCSI_MAX_SG_SEGMENTS > 64)
57 #if (SCSI_MAX_SG_SEGMENTS > 128)
59 #if (SCSI_MAX_SG_SEGMENTS > 256)
60 #error SCSI_MAX_SG_SEGMENTS is too large (256 MAX)
65 SP(SCSI_MAX_SG_SEGMENTS
)
69 struct kmem_cache
*scsi_sdb_cache
;
72 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
73 * not change behaviour from the previous unplug mechanism, experimentation
74 * may prove this needs changing.
76 #define SCSI_QUEUE_DELAY 3
79 * Function: scsi_unprep_request()
81 * Purpose: Remove all preparation done for a request, including its
82 * associated scsi_cmnd, so that it can be requeued.
84 * Arguments: req - request to unprepare
86 * Lock status: Assumed that no locks are held upon entry.
90 static void scsi_unprep_request(struct request
*req
)
92 struct scsi_cmnd
*cmd
= req
->special
;
94 blk_unprep_request(req
);
97 scsi_put_command(cmd
);
101 * __scsi_queue_insert - private queue insertion
102 * @cmd: The SCSI command being requeued
103 * @reason: The reason for the requeue
104 * @unbusy: Whether the queue should be unbusied
106 * This is a private queue insertion. The public interface
107 * scsi_queue_insert() always assumes the queue should be unbusied
108 * because it's always called before the completion. This function is
109 * for a requeue after completion, which should only occur in this
112 static int __scsi_queue_insert(struct scsi_cmnd
*cmd
, int reason
, int unbusy
)
114 struct Scsi_Host
*host
= cmd
->device
->host
;
115 struct scsi_device
*device
= cmd
->device
;
116 struct scsi_target
*starget
= scsi_target(device
);
117 struct request_queue
*q
= device
->request_queue
;
121 printk("Inserting command %p into mlqueue\n", cmd
));
124 * Set the appropriate busy bit for the device/host.
126 * If the host/device isn't busy, assume that something actually
127 * completed, and that we should be able to queue a command now.
129 * Note that the prior mid-layer assumption that any host could
130 * always queue at least one command is now broken. The mid-layer
131 * will implement a user specifiable stall (see
132 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
133 * if a command is requeued with no other commands outstanding
134 * either for the device or for the host.
137 case SCSI_MLQUEUE_HOST_BUSY
:
138 host
->host_blocked
= host
->max_host_blocked
;
140 case SCSI_MLQUEUE_DEVICE_BUSY
:
141 case SCSI_MLQUEUE_EH_RETRY
:
142 device
->device_blocked
= device
->max_device_blocked
;
144 case SCSI_MLQUEUE_TARGET_BUSY
:
145 starget
->target_blocked
= starget
->max_target_blocked
;
150 * Decrement the counters, since these commands are no longer
151 * active on the host/device.
154 scsi_device_unbusy(device
);
157 * Requeue this command. It will go before all other commands
158 * that are already in the queue.
160 spin_lock_irqsave(q
->queue_lock
, flags
);
161 blk_requeue_request(q
, cmd
->request
);
162 spin_unlock_irqrestore(q
->queue_lock
, flags
);
164 kblockd_schedule_work(q
, &device
->requeue_work
);
170 * Function: scsi_queue_insert()
172 * Purpose: Insert a command in the midlevel queue.
174 * Arguments: cmd - command that we are adding to queue.
175 * reason - why we are inserting command to queue.
177 * Lock status: Assumed that lock is not held upon entry.
181 * Notes: We do this for one of two cases. Either the host is busy
182 * and it cannot accept any more commands for the time being,
183 * or the device returned QUEUE_FULL and can accept no more
185 * Notes: This could be called either from an interrupt context or a
186 * normal process context.
188 int scsi_queue_insert(struct scsi_cmnd
*cmd
, int reason
)
190 return __scsi_queue_insert(cmd
, reason
, 1);
193 * scsi_execute - insert request and wait for the result
196 * @data_direction: data direction
197 * @buffer: data buffer
198 * @bufflen: len of buffer
199 * @sense: optional sense buffer
200 * @timeout: request timeout in seconds
201 * @retries: number of times to retry request
202 * @flags: or into request flags;
203 * @resid: optional residual length
205 * returns the req->errors value which is the scsi_cmnd result
208 int scsi_execute(struct scsi_device
*sdev
, const unsigned char *cmd
,
209 int data_direction
, void *buffer
, unsigned bufflen
,
210 unsigned char *sense
, int timeout
, int retries
, int flags
,
214 int write
= (data_direction
== DMA_TO_DEVICE
);
215 int ret
= DRIVER_ERROR
<< 24;
217 req
= blk_get_request(sdev
->request_queue
, write
, __GFP_WAIT
);
221 if (bufflen
&& blk_rq_map_kern(sdev
->request_queue
, req
,
222 buffer
, bufflen
, __GFP_WAIT
))
225 req
->cmd_len
= COMMAND_SIZE(cmd
[0]);
226 memcpy(req
->cmd
, cmd
, req
->cmd_len
);
229 req
->retries
= retries
;
230 req
->timeout
= timeout
;
231 req
->cmd_type
= REQ_TYPE_BLOCK_PC
;
232 req
->cmd_flags
|= flags
| REQ_QUIET
| REQ_PREEMPT
;
235 * head injection *required* here otherwise quiesce won't work
237 blk_execute_rq(req
->q
, NULL
, req
, 1);
240 * Some devices (USB mass-storage in particular) may transfer
241 * garbage data together with a residue indicating that the data
242 * is invalid. Prevent the garbage from being misinterpreted
243 * and prevent security leaks by zeroing out the excess data.
245 if (unlikely(req
->resid_len
> 0 && req
->resid_len
<= bufflen
))
246 memset(buffer
+ (bufflen
- req
->resid_len
), 0, req
->resid_len
);
249 *resid
= req
->resid_len
;
252 blk_put_request(req
);
256 EXPORT_SYMBOL(scsi_execute
);
259 int scsi_execute_req(struct scsi_device
*sdev
, const unsigned char *cmd
,
260 int data_direction
, void *buffer
, unsigned bufflen
,
261 struct scsi_sense_hdr
*sshdr
, int timeout
, int retries
,
268 sense
= kzalloc(SCSI_SENSE_BUFFERSIZE
, GFP_NOIO
);
270 return DRIVER_ERROR
<< 24;
272 result
= scsi_execute(sdev
, cmd
, data_direction
, buffer
, bufflen
,
273 sense
, timeout
, retries
, 0, resid
);
275 scsi_normalize_sense(sense
, SCSI_SENSE_BUFFERSIZE
, sshdr
);
280 EXPORT_SYMBOL(scsi_execute_req
);
283 * Function: scsi_init_cmd_errh()
285 * Purpose: Initialize cmd fields related to error handling.
287 * Arguments: cmd - command that is ready to be queued.
289 * Notes: This function has the job of initializing a number of
290 * fields related to error handling. Typically this will
291 * be called once for each command, as required.
293 static void scsi_init_cmd_errh(struct scsi_cmnd
*cmd
)
295 cmd
->serial_number
= 0;
296 scsi_set_resid(cmd
, 0);
297 memset(cmd
->sense_buffer
, 0, SCSI_SENSE_BUFFERSIZE
);
298 if (cmd
->cmd_len
== 0)
299 cmd
->cmd_len
= scsi_command_size(cmd
->cmnd
);
302 void scsi_device_unbusy(struct scsi_device
*sdev
)
304 struct Scsi_Host
*shost
= sdev
->host
;
305 struct scsi_target
*starget
= scsi_target(sdev
);
308 spin_lock_irqsave(shost
->host_lock
, flags
);
310 starget
->target_busy
--;
311 if (unlikely(scsi_host_in_recovery(shost
) &&
312 (shost
->host_failed
|| shost
->host_eh_scheduled
)))
313 scsi_eh_wakeup(shost
);
314 spin_unlock(shost
->host_lock
);
315 spin_lock(sdev
->request_queue
->queue_lock
);
317 spin_unlock_irqrestore(sdev
->request_queue
->queue_lock
, flags
);
321 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
322 * and call blk_run_queue for all the scsi_devices on the target -
323 * including current_sdev first.
325 * Called with *no* scsi locks held.
327 static void scsi_single_lun_run(struct scsi_device
*current_sdev
)
329 struct Scsi_Host
*shost
= current_sdev
->host
;
330 struct scsi_device
*sdev
, *tmp
;
331 struct scsi_target
*starget
= scsi_target(current_sdev
);
334 spin_lock_irqsave(shost
->host_lock
, flags
);
335 starget
->starget_sdev_user
= NULL
;
336 spin_unlock_irqrestore(shost
->host_lock
, flags
);
339 * Call blk_run_queue for all LUNs on the target, starting with
340 * current_sdev. We race with others (to set starget_sdev_user),
341 * but in most cases, we will be first. Ideally, each LU on the
342 * target would get some limited time or requests on the target.
344 blk_run_queue(current_sdev
->request_queue
);
346 spin_lock_irqsave(shost
->host_lock
, flags
);
347 if (starget
->starget_sdev_user
)
349 list_for_each_entry_safe(sdev
, tmp
, &starget
->devices
,
350 same_target_siblings
) {
351 if (sdev
== current_sdev
)
353 if (scsi_device_get(sdev
))
356 spin_unlock_irqrestore(shost
->host_lock
, flags
);
357 blk_run_queue(sdev
->request_queue
);
358 spin_lock_irqsave(shost
->host_lock
, flags
);
360 scsi_device_put(sdev
);
363 spin_unlock_irqrestore(shost
->host_lock
, flags
);
366 static inline int scsi_device_is_busy(struct scsi_device
*sdev
)
368 if (sdev
->device_busy
>= sdev
->queue_depth
|| sdev
->device_blocked
)
374 static inline int scsi_target_is_busy(struct scsi_target
*starget
)
376 return ((starget
->can_queue
> 0 &&
377 starget
->target_busy
>= starget
->can_queue
) ||
378 starget
->target_blocked
);
381 static inline int scsi_host_is_busy(struct Scsi_Host
*shost
)
383 if ((shost
->can_queue
> 0 && shost
->host_busy
>= shost
->can_queue
) ||
384 shost
->host_blocked
|| shost
->host_self_blocked
)
391 * Function: scsi_run_queue()
393 * Purpose: Select a proper request queue to serve next
395 * Arguments: q - last request's queue
399 * Notes: The previous command was completely finished, start
400 * a new one if possible.
402 static void scsi_run_queue(struct request_queue
*q
)
404 struct scsi_device
*sdev
= q
->queuedata
;
405 struct Scsi_Host
*shost
;
406 LIST_HEAD(starved_list
);
409 /* if the device is dead, sdev will be NULL, so no queue to run */
414 if (scsi_target(sdev
)->single_lun
)
415 scsi_single_lun_run(sdev
);
417 spin_lock_irqsave(shost
->host_lock
, flags
);
418 list_splice_init(&shost
->starved_list
, &starved_list
);
420 while (!list_empty(&starved_list
)) {
422 * As long as shost is accepting commands and we have
423 * starved queues, call blk_run_queue. scsi_request_fn
424 * drops the queue_lock and can add us back to the
427 * host_lock protects the starved_list and starved_entry.
428 * scsi_request_fn must get the host_lock before checking
429 * or modifying starved_list or starved_entry.
431 if (scsi_host_is_busy(shost
))
434 sdev
= list_entry(starved_list
.next
,
435 struct scsi_device
, starved_entry
);
436 list_del_init(&sdev
->starved_entry
);
437 if (scsi_target_is_busy(scsi_target(sdev
))) {
438 list_move_tail(&sdev
->starved_entry
,
439 &shost
->starved_list
);
443 spin_unlock(shost
->host_lock
);
444 spin_lock(sdev
->request_queue
->queue_lock
);
445 __blk_run_queue(sdev
->request_queue
);
446 spin_unlock(sdev
->request_queue
->queue_lock
);
447 spin_lock(shost
->host_lock
);
449 /* put any unprocessed entries back */
450 list_splice(&starved_list
, &shost
->starved_list
);
451 spin_unlock_irqrestore(shost
->host_lock
, flags
);
456 void scsi_requeue_run_queue(struct work_struct
*work
)
458 struct scsi_device
*sdev
;
459 struct request_queue
*q
;
461 sdev
= container_of(work
, struct scsi_device
, requeue_work
);
462 q
= sdev
->request_queue
;
467 * Function: scsi_requeue_command()
469 * Purpose: Handle post-processing of completed commands.
471 * Arguments: q - queue to operate on
472 * cmd - command that may need to be requeued.
476 * Notes: After command completion, there may be blocks left
477 * over which weren't finished by the previous command
478 * this can be for a number of reasons - the main one is
479 * I/O errors in the middle of the request, in which case
480 * we need to request the blocks that come after the bad
482 * Notes: Upon return, cmd is a stale pointer.
484 static void scsi_requeue_command(struct request_queue
*q
, struct scsi_cmnd
*cmd
)
486 struct request
*req
= cmd
->request
;
489 spin_lock_irqsave(q
->queue_lock
, flags
);
490 scsi_unprep_request(req
);
491 blk_requeue_request(q
, req
);
492 spin_unlock_irqrestore(q
->queue_lock
, flags
);
497 void scsi_next_command(struct scsi_cmnd
*cmd
)
499 struct scsi_device
*sdev
= cmd
->device
;
500 struct request_queue
*q
= sdev
->request_queue
;
502 /* need to hold a reference on the device before we let go of the cmd */
503 get_device(&sdev
->sdev_gendev
);
505 scsi_put_command(cmd
);
508 /* ok to remove device now */
509 put_device(&sdev
->sdev_gendev
);
512 void scsi_run_host_queues(struct Scsi_Host
*shost
)
514 struct scsi_device
*sdev
;
516 shost_for_each_device(sdev
, shost
)
517 scsi_run_queue(sdev
->request_queue
);
520 static void __scsi_release_buffers(struct scsi_cmnd
*, int);
523 * Function: scsi_end_request()
525 * Purpose: Post-processing of completed commands (usually invoked at end
526 * of upper level post-processing and scsi_io_completion).
528 * Arguments: cmd - command that is complete.
529 * error - 0 if I/O indicates success, < 0 for I/O error.
530 * bytes - number of bytes of completed I/O
531 * requeue - indicates whether we should requeue leftovers.
533 * Lock status: Assumed that lock is not held upon entry.
535 * Returns: cmd if requeue required, NULL otherwise.
537 * Notes: This is called for block device requests in order to
538 * mark some number of sectors as complete.
540 * We are guaranteeing that the request queue will be goosed
541 * at some point during this call.
542 * Notes: If cmd was requeued, upon return it will be a stale pointer.
544 static struct scsi_cmnd
*scsi_end_request(struct scsi_cmnd
*cmd
, int error
,
545 int bytes
, int requeue
)
547 struct request_queue
*q
= cmd
->device
->request_queue
;
548 struct request
*req
= cmd
->request
;
551 * If there are blocks left over at the end, set up the command
552 * to queue the remainder of them.
554 if (blk_end_request(req
, error
, bytes
)) {
555 /* kill remainder if no retrys */
556 if (error
&& scsi_noretry_cmd(cmd
))
557 blk_end_request_all(req
, error
);
561 * Bleah. Leftovers again. Stick the
562 * leftovers in the front of the
563 * queue, and goose the queue again.
565 scsi_release_buffers(cmd
);
566 scsi_requeue_command(q
, cmd
);
574 * This will goose the queue request function at the end, so we don't
575 * need to worry about launching another command.
577 __scsi_release_buffers(cmd
, 0);
578 scsi_next_command(cmd
);
582 static inline unsigned int scsi_sgtable_index(unsigned short nents
)
586 BUG_ON(nents
> SCSI_MAX_SG_SEGMENTS
);
591 index
= get_count_order(nents
) - 3;
596 static void scsi_sg_free(struct scatterlist
*sgl
, unsigned int nents
)
598 struct scsi_host_sg_pool
*sgp
;
600 sgp
= scsi_sg_pools
+ scsi_sgtable_index(nents
);
601 mempool_free(sgl
, sgp
->pool
);
604 static struct scatterlist
*scsi_sg_alloc(unsigned int nents
, gfp_t gfp_mask
)
606 struct scsi_host_sg_pool
*sgp
;
608 sgp
= scsi_sg_pools
+ scsi_sgtable_index(nents
);
609 return mempool_alloc(sgp
->pool
, gfp_mask
);
612 static int scsi_alloc_sgtable(struct scsi_data_buffer
*sdb
, int nents
,
619 ret
= __sg_alloc_table(&sdb
->table
, nents
, SCSI_MAX_SG_SEGMENTS
,
620 gfp_mask
, scsi_sg_alloc
);
622 __sg_free_table(&sdb
->table
, SCSI_MAX_SG_SEGMENTS
,
628 static void scsi_free_sgtable(struct scsi_data_buffer
*sdb
)
630 __sg_free_table(&sdb
->table
, SCSI_MAX_SG_SEGMENTS
, scsi_sg_free
);
633 static void __scsi_release_buffers(struct scsi_cmnd
*cmd
, int do_bidi_check
)
636 if (cmd
->sdb
.table
.nents
)
637 scsi_free_sgtable(&cmd
->sdb
);
639 memset(&cmd
->sdb
, 0, sizeof(cmd
->sdb
));
641 if (do_bidi_check
&& scsi_bidi_cmnd(cmd
)) {
642 struct scsi_data_buffer
*bidi_sdb
=
643 cmd
->request
->next_rq
->special
;
644 scsi_free_sgtable(bidi_sdb
);
645 kmem_cache_free(scsi_sdb_cache
, bidi_sdb
);
646 cmd
->request
->next_rq
->special
= NULL
;
649 if (scsi_prot_sg_count(cmd
))
650 scsi_free_sgtable(cmd
->prot_sdb
);
654 * Function: scsi_release_buffers()
656 * Purpose: Completion processing for block device I/O requests.
658 * Arguments: cmd - command that we are bailing.
660 * Lock status: Assumed that no lock is held upon entry.
664 * Notes: In the event that an upper level driver rejects a
665 * command, we must release resources allocated during
666 * the __init_io() function. Primarily this would involve
667 * the scatter-gather table, and potentially any bounce
670 void scsi_release_buffers(struct scsi_cmnd
*cmd
)
672 __scsi_release_buffers(cmd
, 1);
674 EXPORT_SYMBOL(scsi_release_buffers
);
676 static int __scsi_error_from_host_byte(struct scsi_cmnd
*cmd
, int result
)
680 switch(host_byte(result
)) {
681 case DID_TRANSPORT_FAILFAST
:
684 case DID_TARGET_FAILURE
:
685 cmd
->result
|= (DID_OK
<< 16);
688 case DID_NEXUS_FAILURE
:
689 cmd
->result
|= (DID_OK
<< 16);
701 * Function: scsi_io_completion()
703 * Purpose: Completion processing for block device I/O requests.
705 * Arguments: cmd - command that is finished.
707 * Lock status: Assumed that no lock is held upon entry.
711 * Notes: This function is matched in terms of capabilities to
712 * the function that created the scatter-gather list.
713 * In other words, if there are no bounce buffers
714 * (the normal case for most drivers), we don't need
715 * the logic to deal with cleaning up afterwards.
717 * We must call scsi_end_request(). This will finish off
718 * the specified number of sectors. If we are done, the
719 * command block will be released and the queue function
720 * will be goosed. If we are not done then we have to
721 * figure out what to do next:
723 * a) We can call scsi_requeue_command(). The request
724 * will be unprepared and put back on the queue. Then
725 * a new command will be created for it. This should
726 * be used if we made forward progress, or if we want
727 * to switch from READ(10) to READ(6) for example.
729 * b) We can call scsi_queue_insert(). The request will
730 * be put back on the queue and retried using the same
731 * command as before, possibly after a delay.
733 * c) We can call blk_end_request() with -EIO to fail
734 * the remainder of the request.
736 void scsi_io_completion(struct scsi_cmnd
*cmd
, unsigned int good_bytes
)
738 int result
= cmd
->result
;
739 struct request_queue
*q
= cmd
->device
->request_queue
;
740 struct request
*req
= cmd
->request
;
742 struct scsi_sense_hdr sshdr
;
744 int sense_deferred
= 0;
745 enum {ACTION_FAIL
, ACTION_REPREP
, ACTION_RETRY
,
746 ACTION_DELAYED_RETRY
} action
;
747 char *description
= NULL
;
750 sense_valid
= scsi_command_normalize_sense(cmd
, &sshdr
);
752 sense_deferred
= scsi_sense_is_deferred(&sshdr
);
755 if (req
->cmd_type
== REQ_TYPE_BLOCK_PC
) { /* SG_IO ioctl from block level */
756 req
->errors
= result
;
758 if (sense_valid
&& req
->sense
) {
760 * SG_IO wants current and deferred errors
762 int len
= 8 + cmd
->sense_buffer
[7];
764 if (len
> SCSI_SENSE_BUFFERSIZE
)
765 len
= SCSI_SENSE_BUFFERSIZE
;
766 memcpy(req
->sense
, cmd
->sense_buffer
, len
);
767 req
->sense_len
= len
;
770 error
= __scsi_error_from_host_byte(cmd
, result
);
773 req
->resid_len
= scsi_get_resid(cmd
);
775 if (scsi_bidi_cmnd(cmd
)) {
777 * Bidi commands Must be complete as a whole,
778 * both sides at once.
780 req
->next_rq
->resid_len
= scsi_in(cmd
)->resid
;
782 scsi_release_buffers(cmd
);
783 blk_end_request_all(req
, 0);
785 scsi_next_command(cmd
);
790 /* no bidi support for !REQ_TYPE_BLOCK_PC yet */
791 BUG_ON(blk_bidi_rq(req
));
794 * Next deal with any sectors which we were able to correctly
797 SCSI_LOG_HLCOMPLETE(1, printk("%u sectors total, "
799 blk_rq_sectors(req
), good_bytes
));
802 * Recovered errors need reporting, but they're always treated
803 * as success, so fiddle the result code here. For BLOCK_PC
804 * we already took a copy of the original into rq->errors which
805 * is what gets returned to the user
807 if (sense_valid
&& (sshdr
.sense_key
== RECOVERED_ERROR
)) {
808 /* if ATA PASS-THROUGH INFORMATION AVAILABLE skip
809 * print since caller wants ATA registers. Only occurs on
810 * SCSI ATA PASS_THROUGH commands when CK_COND=1
812 if ((sshdr
.asc
== 0x0) && (sshdr
.ascq
== 0x1d))
814 else if (!(req
->cmd_flags
& REQ_QUIET
))
815 scsi_print_sense("", cmd
);
817 /* BLOCK_PC may have set error */
822 * A number of bytes were successfully read. If there
823 * are leftovers and there is some kind of error
824 * (result != 0), retry the rest.
826 if (scsi_end_request(cmd
, error
, good_bytes
, result
== 0) == NULL
)
829 error
= __scsi_error_from_host_byte(cmd
, result
);
831 if (host_byte(result
) == DID_RESET
) {
832 /* Third party bus reset or reset for error recovery
833 * reasons. Just retry the command and see what
836 action
= ACTION_RETRY
;
837 } else if (sense_valid
&& !sense_deferred
) {
838 switch (sshdr
.sense_key
) {
840 if (cmd
->device
->removable
) {
841 /* Detected disc change. Set a bit
842 * and quietly refuse further access.
844 cmd
->device
->changed
= 1;
845 description
= "Media Changed";
846 action
= ACTION_FAIL
;
848 /* Must have been a power glitch, or a
849 * bus reset. Could not have been a
850 * media change, so we just retry the
851 * command and see what happens.
853 action
= ACTION_RETRY
;
856 case ILLEGAL_REQUEST
:
857 /* If we had an ILLEGAL REQUEST returned, then
858 * we may have performed an unsupported
859 * command. The only thing this should be
860 * would be a ten byte read where only a six
861 * byte read was supported. Also, on a system
862 * where READ CAPACITY failed, we may have
863 * read past the end of the disk.
865 if ((cmd
->device
->use_10_for_rw
&&
866 sshdr
.asc
== 0x20 && sshdr
.ascq
== 0x00) &&
867 (cmd
->cmnd
[0] == READ_10
||
868 cmd
->cmnd
[0] == WRITE_10
)) {
869 /* This will issue a new 6-byte command. */
870 cmd
->device
->use_10_for_rw
= 0;
871 action
= ACTION_REPREP
;
872 } else if (sshdr
.asc
== 0x10) /* DIX */ {
873 description
= "Host Data Integrity Failure";
874 action
= ACTION_FAIL
;
876 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
877 } else if ((sshdr
.asc
== 0x20 || sshdr
.asc
== 0x24) &&
878 (cmd
->cmnd
[0] == UNMAP
||
879 cmd
->cmnd
[0] == WRITE_SAME_16
||
880 cmd
->cmnd
[0] == WRITE_SAME
)) {
881 description
= "Discard failure";
882 action
= ACTION_FAIL
;
884 action
= ACTION_FAIL
;
886 case ABORTED_COMMAND
:
887 action
= ACTION_FAIL
;
888 if (sshdr
.asc
== 0x10) { /* DIF */
889 description
= "Target Data Integrity Failure";
894 /* If the device is in the process of becoming
895 * ready, or has a temporary blockage, retry.
897 if (sshdr
.asc
== 0x04) {
898 switch (sshdr
.ascq
) {
899 case 0x01: /* becoming ready */
900 case 0x04: /* format in progress */
901 case 0x05: /* rebuild in progress */
902 case 0x06: /* recalculation in progress */
903 case 0x07: /* operation in progress */
904 case 0x08: /* Long write in progress */
905 case 0x09: /* self test in progress */
906 case 0x14: /* space allocation in progress */
907 action
= ACTION_DELAYED_RETRY
;
910 description
= "Device not ready";
911 action
= ACTION_FAIL
;
915 description
= "Device not ready";
916 action
= ACTION_FAIL
;
919 case VOLUME_OVERFLOW
:
920 /* See SSC3rXX or current. */
921 action
= ACTION_FAIL
;
924 description
= "Unhandled sense code";
925 action
= ACTION_FAIL
;
929 description
= "Unhandled error code";
930 action
= ACTION_FAIL
;
935 /* Give up and fail the remainder of the request */
936 scsi_release_buffers(cmd
);
937 if (!(req
->cmd_flags
& REQ_QUIET
)) {
939 scmd_printk(KERN_INFO
, cmd
, "%s\n",
941 scsi_print_result(cmd
);
942 if (driver_byte(result
) & DRIVER_SENSE
)
943 scsi_print_sense("", cmd
);
944 scsi_print_command(cmd
);
946 if (blk_end_request_err(req
, error
))
947 scsi_requeue_command(q
, cmd
);
949 scsi_next_command(cmd
);
952 /* Unprep the request and put it back at the head of the queue.
953 * A new command will be prepared and issued.
955 scsi_release_buffers(cmd
);
956 scsi_requeue_command(q
, cmd
);
959 /* Retry the same command immediately */
960 __scsi_queue_insert(cmd
, SCSI_MLQUEUE_EH_RETRY
, 0);
962 case ACTION_DELAYED_RETRY
:
963 /* Retry the same command after a delay */
964 __scsi_queue_insert(cmd
, SCSI_MLQUEUE_DEVICE_BUSY
, 0);
969 static int scsi_init_sgtable(struct request
*req
, struct scsi_data_buffer
*sdb
,
975 * If sg table allocation fails, requeue request later.
977 if (unlikely(scsi_alloc_sgtable(sdb
, req
->nr_phys_segments
,
979 return BLKPREP_DEFER
;
985 * Next, walk the list, and fill in the addresses and sizes of
988 count
= blk_rq_map_sg(req
->q
, req
, sdb
->table
.sgl
);
989 BUG_ON(count
> sdb
->table
.nents
);
990 sdb
->table
.nents
= count
;
991 sdb
->length
= blk_rq_bytes(req
);
996 * Function: scsi_init_io()
998 * Purpose: SCSI I/O initialize function.
1000 * Arguments: cmd - Command descriptor we wish to initialize
1002 * Returns: 0 on success
1003 * BLKPREP_DEFER if the failure is retryable
1004 * BLKPREP_KILL if the failure is fatal
1006 int scsi_init_io(struct scsi_cmnd
*cmd
, gfp_t gfp_mask
)
1008 struct request
*rq
= cmd
->request
;
1010 int error
= scsi_init_sgtable(rq
, &cmd
->sdb
, gfp_mask
);
1014 if (blk_bidi_rq(rq
)) {
1015 struct scsi_data_buffer
*bidi_sdb
= kmem_cache_zalloc(
1016 scsi_sdb_cache
, GFP_ATOMIC
);
1018 error
= BLKPREP_DEFER
;
1022 rq
->next_rq
->special
= bidi_sdb
;
1023 error
= scsi_init_sgtable(rq
->next_rq
, bidi_sdb
, GFP_ATOMIC
);
1028 if (blk_integrity_rq(rq
)) {
1029 struct scsi_data_buffer
*prot_sdb
= cmd
->prot_sdb
;
1032 BUG_ON(prot_sdb
== NULL
);
1033 ivecs
= blk_rq_count_integrity_sg(rq
->q
, rq
->bio
);
1035 if (scsi_alloc_sgtable(prot_sdb
, ivecs
, gfp_mask
)) {
1036 error
= BLKPREP_DEFER
;
1040 count
= blk_rq_map_integrity_sg(rq
->q
, rq
->bio
,
1041 prot_sdb
->table
.sgl
);
1042 BUG_ON(unlikely(count
> ivecs
));
1043 BUG_ON(unlikely(count
> queue_max_integrity_segments(rq
->q
)));
1045 cmd
->prot_sdb
= prot_sdb
;
1046 cmd
->prot_sdb
->table
.nents
= count
;
1052 scsi_release_buffers(cmd
);
1053 cmd
->request
->special
= NULL
;
1054 scsi_put_command(cmd
);
1057 EXPORT_SYMBOL(scsi_init_io
);
1059 static struct scsi_cmnd
*scsi_get_cmd_from_req(struct scsi_device
*sdev
,
1060 struct request
*req
)
1062 struct scsi_cmnd
*cmd
;
1064 if (!req
->special
) {
1065 cmd
= scsi_get_command(sdev
, GFP_ATOMIC
);
1073 /* pull a tag out of the request if we have one */
1074 cmd
->tag
= req
->tag
;
1077 cmd
->cmnd
= req
->cmd
;
1078 cmd
->prot_op
= SCSI_PROT_NORMAL
;
1083 int scsi_setup_blk_pc_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1085 struct scsi_cmnd
*cmd
;
1086 int ret
= scsi_prep_state_check(sdev
, req
);
1088 if (ret
!= BLKPREP_OK
)
1091 cmd
= scsi_get_cmd_from_req(sdev
, req
);
1093 return BLKPREP_DEFER
;
1096 * BLOCK_PC requests may transfer data, in which case they must
1097 * a bio attached to them. Or they might contain a SCSI command
1098 * that does not transfer data, in which case they may optionally
1099 * submit a request without an attached bio.
1104 BUG_ON(!req
->nr_phys_segments
);
1106 ret
= scsi_init_io(cmd
, GFP_ATOMIC
);
1110 BUG_ON(blk_rq_bytes(req
));
1112 memset(&cmd
->sdb
, 0, sizeof(cmd
->sdb
));
1116 cmd
->cmd_len
= req
->cmd_len
;
1117 if (!blk_rq_bytes(req
))
1118 cmd
->sc_data_direction
= DMA_NONE
;
1119 else if (rq_data_dir(req
) == WRITE
)
1120 cmd
->sc_data_direction
= DMA_TO_DEVICE
;
1122 cmd
->sc_data_direction
= DMA_FROM_DEVICE
;
1124 cmd
->transfersize
= blk_rq_bytes(req
);
1125 cmd
->allowed
= req
->retries
;
1128 EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd
);
1131 * Setup a REQ_TYPE_FS command. These are simple read/write request
1132 * from filesystems that still need to be translated to SCSI CDBs from
1135 int scsi_setup_fs_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1137 struct scsi_cmnd
*cmd
;
1138 int ret
= scsi_prep_state_check(sdev
, req
);
1140 if (ret
!= BLKPREP_OK
)
1143 if (unlikely(sdev
->scsi_dh_data
&& sdev
->scsi_dh_data
->scsi_dh
1144 && sdev
->scsi_dh_data
->scsi_dh
->prep_fn
)) {
1145 ret
= sdev
->scsi_dh_data
->scsi_dh
->prep_fn(sdev
, req
);
1146 if (ret
!= BLKPREP_OK
)
1151 * Filesystem requests must transfer data.
1153 BUG_ON(!req
->nr_phys_segments
);
1155 cmd
= scsi_get_cmd_from_req(sdev
, req
);
1157 return BLKPREP_DEFER
;
1159 memset(cmd
->cmnd
, 0, BLK_MAX_CDB
);
1160 return scsi_init_io(cmd
, GFP_ATOMIC
);
1162 EXPORT_SYMBOL(scsi_setup_fs_cmnd
);
1164 int scsi_prep_state_check(struct scsi_device
*sdev
, struct request
*req
)
1166 int ret
= BLKPREP_OK
;
1169 * If the device is not in running state we will reject some
1172 if (unlikely(sdev
->sdev_state
!= SDEV_RUNNING
)) {
1173 switch (sdev
->sdev_state
) {
1176 * If the device is offline we refuse to process any
1177 * commands. The device must be brought online
1178 * before trying any recovery commands.
1180 sdev_printk(KERN_ERR
, sdev
,
1181 "rejecting I/O to offline device\n");
1186 * If the device is fully deleted, we refuse to
1187 * process any commands as well.
1189 sdev_printk(KERN_ERR
, sdev
,
1190 "rejecting I/O to dead device\n");
1195 case SDEV_CREATED_BLOCK
:
1197 * If the devices is blocked we defer normal commands.
1199 if (!(req
->cmd_flags
& REQ_PREEMPT
))
1200 ret
= BLKPREP_DEFER
;
1204 * For any other not fully online state we only allow
1205 * special commands. In particular any user initiated
1206 * command is not allowed.
1208 if (!(req
->cmd_flags
& REQ_PREEMPT
))
1215 EXPORT_SYMBOL(scsi_prep_state_check
);
1217 int scsi_prep_return(struct request_queue
*q
, struct request
*req
, int ret
)
1219 struct scsi_device
*sdev
= q
->queuedata
;
1223 req
->errors
= DID_NO_CONNECT
<< 16;
1224 /* release the command and kill it */
1226 struct scsi_cmnd
*cmd
= req
->special
;
1227 scsi_release_buffers(cmd
);
1228 scsi_put_command(cmd
);
1229 req
->special
= NULL
;
1234 * If we defer, the blk_peek_request() returns NULL, but the
1235 * queue must be restarted, so we schedule a callback to happen
1238 if (sdev
->device_busy
== 0)
1239 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1242 req
->cmd_flags
|= REQ_DONTPREP
;
1247 EXPORT_SYMBOL(scsi_prep_return
);
1249 int scsi_prep_fn(struct request_queue
*q
, struct request
*req
)
1251 struct scsi_device
*sdev
= q
->queuedata
;
1252 int ret
= BLKPREP_KILL
;
1254 if (req
->cmd_type
== REQ_TYPE_BLOCK_PC
)
1255 ret
= scsi_setup_blk_pc_cmnd(sdev
, req
);
1256 return scsi_prep_return(q
, req
, ret
);
1258 EXPORT_SYMBOL(scsi_prep_fn
);
1261 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1264 * Called with the queue_lock held.
1266 static inline int scsi_dev_queue_ready(struct request_queue
*q
,
1267 struct scsi_device
*sdev
)
1269 if (sdev
->device_busy
== 0 && sdev
->device_blocked
) {
1271 * unblock after device_blocked iterates to zero
1273 if (--sdev
->device_blocked
== 0) {
1275 sdev_printk(KERN_INFO
, sdev
,
1276 "unblocking device at zero depth\n"));
1278 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1282 if (scsi_device_is_busy(sdev
))
1290 * scsi_target_queue_ready: checks if there we can send commands to target
1291 * @sdev: scsi device on starget to check.
1293 * Called with the host lock held.
1295 static inline int scsi_target_queue_ready(struct Scsi_Host
*shost
,
1296 struct scsi_device
*sdev
)
1298 struct scsi_target
*starget
= scsi_target(sdev
);
1300 if (starget
->single_lun
) {
1301 if (starget
->starget_sdev_user
&&
1302 starget
->starget_sdev_user
!= sdev
)
1304 starget
->starget_sdev_user
= sdev
;
1307 if (starget
->target_busy
== 0 && starget
->target_blocked
) {
1309 * unblock after target_blocked iterates to zero
1311 if (--starget
->target_blocked
== 0) {
1312 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO
, starget
,
1313 "unblocking target at zero depth\n"));
1318 if (scsi_target_is_busy(starget
)) {
1319 if (list_empty(&sdev
->starved_entry
))
1320 list_add_tail(&sdev
->starved_entry
,
1321 &shost
->starved_list
);
1325 /* We're OK to process the command, so we can't be starved */
1326 if (!list_empty(&sdev
->starved_entry
))
1327 list_del_init(&sdev
->starved_entry
);
1332 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1333 * return 0. We must end up running the queue again whenever 0 is
1334 * returned, else IO can hang.
1336 * Called with host_lock held.
1338 static inline int scsi_host_queue_ready(struct request_queue
*q
,
1339 struct Scsi_Host
*shost
,
1340 struct scsi_device
*sdev
)
1342 if (scsi_host_in_recovery(shost
))
1344 if (shost
->host_busy
== 0 && shost
->host_blocked
) {
1346 * unblock after host_blocked iterates to zero
1348 if (--shost
->host_blocked
== 0) {
1350 printk("scsi%d unblocking host at zero depth\n",
1356 if (scsi_host_is_busy(shost
)) {
1357 if (list_empty(&sdev
->starved_entry
))
1358 list_add_tail(&sdev
->starved_entry
, &shost
->starved_list
);
1362 /* We're OK to process the command, so we can't be starved */
1363 if (!list_empty(&sdev
->starved_entry
))
1364 list_del_init(&sdev
->starved_entry
);
1370 * Busy state exporting function for request stacking drivers.
1372 * For efficiency, no lock is taken to check the busy state of
1373 * shost/starget/sdev, since the returned value is not guaranteed and
1374 * may be changed after request stacking drivers call the function,
1375 * regardless of taking lock or not.
1377 * When scsi can't dispatch I/Os anymore and needs to kill I/Os
1378 * (e.g. !sdev), scsi needs to return 'not busy'.
1379 * Otherwise, request stacking drivers may hold requests forever.
1381 static int scsi_lld_busy(struct request_queue
*q
)
1383 struct scsi_device
*sdev
= q
->queuedata
;
1384 struct Scsi_Host
*shost
;
1385 struct scsi_target
*starget
;
1391 starget
= scsi_target(sdev
);
1393 if (scsi_host_in_recovery(shost
) || scsi_host_is_busy(shost
) ||
1394 scsi_target_is_busy(starget
) || scsi_device_is_busy(sdev
))
1401 * Kill a request for a dead device
1403 static void scsi_kill_request(struct request
*req
, struct request_queue
*q
)
1405 struct scsi_cmnd
*cmd
= req
->special
;
1406 struct scsi_device
*sdev
;
1407 struct scsi_target
*starget
;
1408 struct Scsi_Host
*shost
;
1410 blk_start_request(req
);
1413 starget
= scsi_target(sdev
);
1415 scsi_init_cmd_errh(cmd
);
1416 cmd
->result
= DID_NO_CONNECT
<< 16;
1417 atomic_inc(&cmd
->device
->iorequest_cnt
);
1420 * SCSI request completion path will do scsi_device_unbusy(),
1421 * bump busy counts. To bump the counters, we need to dance
1422 * with the locks as normal issue path does.
1424 sdev
->device_busy
++;
1425 spin_unlock(sdev
->request_queue
->queue_lock
);
1426 spin_lock(shost
->host_lock
);
1428 starget
->target_busy
++;
1429 spin_unlock(shost
->host_lock
);
1430 spin_lock(sdev
->request_queue
->queue_lock
);
1432 blk_complete_request(req
);
1435 static void scsi_softirq_done(struct request
*rq
)
1437 struct scsi_cmnd
*cmd
= rq
->special
;
1438 unsigned long wait_for
= (cmd
->allowed
+ 1) * rq
->timeout
;
1441 INIT_LIST_HEAD(&cmd
->eh_entry
);
1443 atomic_inc(&cmd
->device
->iodone_cnt
);
1445 atomic_inc(&cmd
->device
->ioerr_cnt
);
1447 disposition
= scsi_decide_disposition(cmd
);
1448 if (disposition
!= SUCCESS
&&
1449 time_before(cmd
->jiffies_at_alloc
+ wait_for
, jiffies
)) {
1450 sdev_printk(KERN_ERR
, cmd
->device
,
1451 "timing out command, waited %lus\n",
1453 disposition
= SUCCESS
;
1456 scsi_log_completion(cmd
, disposition
);
1458 switch (disposition
) {
1460 scsi_finish_command(cmd
);
1463 scsi_queue_insert(cmd
, SCSI_MLQUEUE_EH_RETRY
);
1465 case ADD_TO_MLQUEUE
:
1466 scsi_queue_insert(cmd
, SCSI_MLQUEUE_DEVICE_BUSY
);
1469 if (!scsi_eh_scmd_add(cmd
, 0))
1470 scsi_finish_command(cmd
);
1475 * Function: scsi_request_fn()
1477 * Purpose: Main strategy routine for SCSI.
1479 * Arguments: q - Pointer to actual queue.
1483 * Lock status: IO request lock assumed to be held when called.
1485 static void scsi_request_fn(struct request_queue
*q
)
1487 struct scsi_device
*sdev
= q
->queuedata
;
1488 struct Scsi_Host
*shost
;
1489 struct scsi_cmnd
*cmd
;
1490 struct request
*req
;
1493 printk("scsi: killing requests for dead queue\n");
1494 while ((req
= blk_peek_request(q
)) != NULL
)
1495 scsi_kill_request(req
, q
);
1499 if(!get_device(&sdev
->sdev_gendev
))
1500 /* We must be tearing the block queue down already */
1504 * To start with, we keep looping until the queue is empty, or until
1505 * the host is no longer able to accept any more requests.
1511 * get next queueable request. We do this early to make sure
1512 * that the request is fully prepared even if we cannot
1515 req
= blk_peek_request(q
);
1516 if (!req
|| !scsi_dev_queue_ready(q
, sdev
))
1519 if (unlikely(!scsi_device_online(sdev
))) {
1520 sdev_printk(KERN_ERR
, sdev
,
1521 "rejecting I/O to offline device\n");
1522 scsi_kill_request(req
, q
);
1528 * Remove the request from the request list.
1530 if (!(blk_queue_tagged(q
) && !blk_queue_start_tag(q
, req
)))
1531 blk_start_request(req
);
1532 sdev
->device_busy
++;
1534 spin_unlock(q
->queue_lock
);
1536 if (unlikely(cmd
== NULL
)) {
1537 printk(KERN_CRIT
"impossible request in %s.\n"
1538 "please mail a stack trace to "
1539 "linux-scsi@vger.kernel.org\n",
1541 blk_dump_rq_flags(req
, "foo");
1544 spin_lock(shost
->host_lock
);
1547 * We hit this when the driver is using a host wide
1548 * tag map. For device level tag maps the queue_depth check
1549 * in the device ready fn would prevent us from trying
1550 * to allocate a tag. Since the map is a shared host resource
1551 * we add the dev to the starved list so it eventually gets
1552 * a run when a tag is freed.
1554 if (blk_queue_tagged(q
) && !blk_rq_tagged(req
)) {
1555 if (list_empty(&sdev
->starved_entry
))
1556 list_add_tail(&sdev
->starved_entry
,
1557 &shost
->starved_list
);
1561 if (!scsi_target_queue_ready(shost
, sdev
))
1564 if (!scsi_host_queue_ready(q
, shost
, sdev
))
1567 scsi_target(sdev
)->target_busy
++;
1571 * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will
1572 * take the lock again.
1574 spin_unlock_irq(shost
->host_lock
);
1577 * Finally, initialize any error handling parameters, and set up
1578 * the timers for timeouts.
1580 scsi_init_cmd_errh(cmd
);
1583 * Dispatch the command to the low-level driver.
1585 rtn
= scsi_dispatch_cmd(cmd
);
1586 spin_lock_irq(q
->queue_lock
);
1594 spin_unlock_irq(shost
->host_lock
);
1597 * lock q, handle tag, requeue req, and decrement device_busy. We
1598 * must return with queue_lock held.
1600 * Decrementing device_busy without checking it is OK, as all such
1601 * cases (host limits or settings) should run the queue at some
1604 spin_lock_irq(q
->queue_lock
);
1605 blk_requeue_request(q
, req
);
1606 sdev
->device_busy
--;
1608 if (sdev
->device_busy
== 0)
1609 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1611 /* must be careful here...if we trigger the ->remove() function
1612 * we cannot be holding the q lock */
1613 spin_unlock_irq(q
->queue_lock
);
1614 put_device(&sdev
->sdev_gendev
);
1615 spin_lock_irq(q
->queue_lock
);
1618 u64
scsi_calculate_bounce_limit(struct Scsi_Host
*shost
)
1620 struct device
*host_dev
;
1621 u64 bounce_limit
= 0xffffffff;
1623 if (shost
->unchecked_isa_dma
)
1624 return BLK_BOUNCE_ISA
;
1626 * Platforms with virtual-DMA translation
1627 * hardware have no practical limit.
1629 if (!PCI_DMA_BUS_IS_PHYS
)
1630 return BLK_BOUNCE_ANY
;
1632 host_dev
= scsi_get_device(shost
);
1633 if (host_dev
&& host_dev
->dma_mask
)
1634 bounce_limit
= *host_dev
->dma_mask
;
1636 return bounce_limit
;
1638 EXPORT_SYMBOL(scsi_calculate_bounce_limit
);
1640 struct request_queue
*__scsi_alloc_queue(struct Scsi_Host
*shost
,
1641 request_fn_proc
*request_fn
)
1643 struct request_queue
*q
;
1644 struct device
*dev
= shost
->shost_gendev
.parent
;
1646 q
= blk_init_queue(request_fn
, NULL
);
1651 * this limit is imposed by hardware restrictions
1653 blk_queue_max_segments(q
, min_t(unsigned short, shost
->sg_tablesize
,
1654 SCSI_MAX_SG_CHAIN_SEGMENTS
));
1656 if (scsi_host_prot_dma(shost
)) {
1657 shost
->sg_prot_tablesize
=
1658 min_not_zero(shost
->sg_prot_tablesize
,
1659 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS
);
1660 BUG_ON(shost
->sg_prot_tablesize
< shost
->sg_tablesize
);
1661 blk_queue_max_integrity_segments(q
, shost
->sg_prot_tablesize
);
1664 blk_queue_max_hw_sectors(q
, shost
->max_sectors
);
1665 blk_queue_bounce_limit(q
, scsi_calculate_bounce_limit(shost
));
1666 blk_queue_segment_boundary(q
, shost
->dma_boundary
);
1667 dma_set_seg_boundary(dev
, shost
->dma_boundary
);
1669 blk_queue_max_segment_size(q
, dma_get_max_seg_size(dev
));
1671 if (!shost
->use_clustering
)
1672 q
->limits
.cluster
= 0;
1675 * set a reasonable default alignment on word boundaries: the
1676 * host and device may alter it using
1677 * blk_queue_update_dma_alignment() later.
1679 blk_queue_dma_alignment(q
, 0x03);
1683 EXPORT_SYMBOL(__scsi_alloc_queue
);
1685 struct request_queue
*scsi_alloc_queue(struct scsi_device
*sdev
)
1687 struct request_queue
*q
;
1689 q
= __scsi_alloc_queue(sdev
->host
, scsi_request_fn
);
1693 blk_queue_prep_rq(q
, scsi_prep_fn
);
1694 blk_queue_softirq_done(q
, scsi_softirq_done
);
1695 blk_queue_rq_timed_out(q
, scsi_times_out
);
1696 blk_queue_lld_busy(q
, scsi_lld_busy
);
1700 void scsi_free_queue(struct request_queue
*q
)
1702 unsigned long flags
;
1704 WARN_ON(q
->queuedata
);
1706 /* cause scsi_request_fn() to kill all non-finished requests */
1707 spin_lock_irqsave(q
->queue_lock
, flags
);
1709 spin_unlock_irqrestore(q
->queue_lock
, flags
);
1711 blk_cleanup_queue(q
);
1715 * Function: scsi_block_requests()
1717 * Purpose: Utility function used by low-level drivers to prevent further
1718 * commands from being queued to the device.
1720 * Arguments: shost - Host in question
1724 * Lock status: No locks are assumed held.
1726 * Notes: There is no timer nor any other means by which the requests
1727 * get unblocked other than the low-level driver calling
1728 * scsi_unblock_requests().
1730 void scsi_block_requests(struct Scsi_Host
*shost
)
1732 shost
->host_self_blocked
= 1;
1734 EXPORT_SYMBOL(scsi_block_requests
);
1737 * Function: scsi_unblock_requests()
1739 * Purpose: Utility function used by low-level drivers to allow further
1740 * commands from being queued to the device.
1742 * Arguments: shost - Host in question
1746 * Lock status: No locks are assumed held.
1748 * Notes: There is no timer nor any other means by which the requests
1749 * get unblocked other than the low-level driver calling
1750 * scsi_unblock_requests().
1752 * This is done as an API function so that changes to the
1753 * internals of the scsi mid-layer won't require wholesale
1754 * changes to drivers that use this feature.
1756 void scsi_unblock_requests(struct Scsi_Host
*shost
)
1758 shost
->host_self_blocked
= 0;
1759 scsi_run_host_queues(shost
);
1761 EXPORT_SYMBOL(scsi_unblock_requests
);
1763 int __init
scsi_init_queue(void)
1767 scsi_sdb_cache
= kmem_cache_create("scsi_data_buffer",
1768 sizeof(struct scsi_data_buffer
),
1770 if (!scsi_sdb_cache
) {
1771 printk(KERN_ERR
"SCSI: can't init scsi sdb cache\n");
1775 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
1776 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
1777 int size
= sgp
->size
* sizeof(struct scatterlist
);
1779 sgp
->slab
= kmem_cache_create(sgp
->name
, size
, 0,
1780 SLAB_HWCACHE_ALIGN
, NULL
);
1782 printk(KERN_ERR
"SCSI: can't init sg slab %s\n",
1787 sgp
->pool
= mempool_create_slab_pool(SG_MEMPOOL_SIZE
,
1790 printk(KERN_ERR
"SCSI: can't init sg mempool %s\n",
1799 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
1800 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
1802 mempool_destroy(sgp
->pool
);
1804 kmem_cache_destroy(sgp
->slab
);
1806 kmem_cache_destroy(scsi_sdb_cache
);
1811 void scsi_exit_queue(void)
1815 kmem_cache_destroy(scsi_sdb_cache
);
1817 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
1818 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
1819 mempool_destroy(sgp
->pool
);
1820 kmem_cache_destroy(sgp
->slab
);
1825 * scsi_mode_select - issue a mode select
1826 * @sdev: SCSI device to be queried
1827 * @pf: Page format bit (1 == standard, 0 == vendor specific)
1828 * @sp: Save page bit (0 == don't save, 1 == save)
1829 * @modepage: mode page being requested
1830 * @buffer: request buffer (may not be smaller than eight bytes)
1831 * @len: length of request buffer.
1832 * @timeout: command timeout
1833 * @retries: number of retries before failing
1834 * @data: returns a structure abstracting the mode header data
1835 * @sshdr: place to put sense data (or NULL if no sense to be collected).
1836 * must be SCSI_SENSE_BUFFERSIZE big.
1838 * Returns zero if successful; negative error number or scsi
1843 scsi_mode_select(struct scsi_device
*sdev
, int pf
, int sp
, int modepage
,
1844 unsigned char *buffer
, int len
, int timeout
, int retries
,
1845 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
1847 unsigned char cmd
[10];
1848 unsigned char *real_buffer
;
1851 memset(cmd
, 0, sizeof(cmd
));
1852 cmd
[1] = (pf
? 0x10 : 0) | (sp
? 0x01 : 0);
1854 if (sdev
->use_10_for_ms
) {
1857 real_buffer
= kmalloc(8 + len
, GFP_KERNEL
);
1860 memcpy(real_buffer
+ 8, buffer
, len
);
1864 real_buffer
[2] = data
->medium_type
;
1865 real_buffer
[3] = data
->device_specific
;
1866 real_buffer
[4] = data
->longlba
? 0x01 : 0;
1868 real_buffer
[6] = data
->block_descriptor_length
>> 8;
1869 real_buffer
[7] = data
->block_descriptor_length
;
1871 cmd
[0] = MODE_SELECT_10
;
1875 if (len
> 255 || data
->block_descriptor_length
> 255 ||
1879 real_buffer
= kmalloc(4 + len
, GFP_KERNEL
);
1882 memcpy(real_buffer
+ 4, buffer
, len
);
1885 real_buffer
[1] = data
->medium_type
;
1886 real_buffer
[2] = data
->device_specific
;
1887 real_buffer
[3] = data
->block_descriptor_length
;
1890 cmd
[0] = MODE_SELECT
;
1894 ret
= scsi_execute_req(sdev
, cmd
, DMA_TO_DEVICE
, real_buffer
, len
,
1895 sshdr
, timeout
, retries
, NULL
);
1899 EXPORT_SYMBOL_GPL(scsi_mode_select
);
1902 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
1903 * @sdev: SCSI device to be queried
1904 * @dbd: set if mode sense will allow block descriptors to be returned
1905 * @modepage: mode page being requested
1906 * @buffer: request buffer (may not be smaller than eight bytes)
1907 * @len: length of request buffer.
1908 * @timeout: command timeout
1909 * @retries: number of retries before failing
1910 * @data: returns a structure abstracting the mode header data
1911 * @sshdr: place to put sense data (or NULL if no sense to be collected).
1912 * must be SCSI_SENSE_BUFFERSIZE big.
1914 * Returns zero if unsuccessful, or the header offset (either 4
1915 * or 8 depending on whether a six or ten byte command was
1916 * issued) if successful.
1919 scsi_mode_sense(struct scsi_device
*sdev
, int dbd
, int modepage
,
1920 unsigned char *buffer
, int len
, int timeout
, int retries
,
1921 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
1923 unsigned char cmd
[12];
1927 struct scsi_sense_hdr my_sshdr
;
1929 memset(data
, 0, sizeof(*data
));
1930 memset(&cmd
[0], 0, 12);
1931 cmd
[1] = dbd
& 0x18; /* allows DBD and LLBA bits */
1934 /* caller might not be interested in sense, but we need it */
1939 use_10_for_ms
= sdev
->use_10_for_ms
;
1941 if (use_10_for_ms
) {
1945 cmd
[0] = MODE_SENSE_10
;
1952 cmd
[0] = MODE_SENSE
;
1957 memset(buffer
, 0, len
);
1959 result
= scsi_execute_req(sdev
, cmd
, DMA_FROM_DEVICE
, buffer
, len
,
1960 sshdr
, timeout
, retries
, NULL
);
1962 /* This code looks awful: what it's doing is making sure an
1963 * ILLEGAL REQUEST sense return identifies the actual command
1964 * byte as the problem. MODE_SENSE commands can return
1965 * ILLEGAL REQUEST if the code page isn't supported */
1967 if (use_10_for_ms
&& !scsi_status_is_good(result
) &&
1968 (driver_byte(result
) & DRIVER_SENSE
)) {
1969 if (scsi_sense_valid(sshdr
)) {
1970 if ((sshdr
->sense_key
== ILLEGAL_REQUEST
) &&
1971 (sshdr
->asc
== 0x20) && (sshdr
->ascq
== 0)) {
1973 * Invalid command operation code
1975 sdev
->use_10_for_ms
= 0;
1981 if(scsi_status_is_good(result
)) {
1982 if (unlikely(buffer
[0] == 0x86 && buffer
[1] == 0x0b &&
1983 (modepage
== 6 || modepage
== 8))) {
1984 /* Initio breakage? */
1987 data
->medium_type
= 0;
1988 data
->device_specific
= 0;
1990 data
->block_descriptor_length
= 0;
1991 } else if(use_10_for_ms
) {
1992 data
->length
= buffer
[0]*256 + buffer
[1] + 2;
1993 data
->medium_type
= buffer
[2];
1994 data
->device_specific
= buffer
[3];
1995 data
->longlba
= buffer
[4] & 0x01;
1996 data
->block_descriptor_length
= buffer
[6]*256
1999 data
->length
= buffer
[0] + 1;
2000 data
->medium_type
= buffer
[1];
2001 data
->device_specific
= buffer
[2];
2002 data
->block_descriptor_length
= buffer
[3];
2004 data
->header_length
= header_length
;
2009 EXPORT_SYMBOL(scsi_mode_sense
);
2012 * scsi_test_unit_ready - test if unit is ready
2013 * @sdev: scsi device to change the state of.
2014 * @timeout: command timeout
2015 * @retries: number of retries before failing
2016 * @sshdr_external: Optional pointer to struct scsi_sense_hdr for
2017 * returning sense. Make sure that this is cleared before passing
2020 * Returns zero if unsuccessful or an error if TUR failed. For
2021 * removable media, UNIT_ATTENTION sets ->changed flag.
2024 scsi_test_unit_ready(struct scsi_device
*sdev
, int timeout
, int retries
,
2025 struct scsi_sense_hdr
*sshdr_external
)
2028 TEST_UNIT_READY
, 0, 0, 0, 0, 0,
2030 struct scsi_sense_hdr
*sshdr
;
2033 if (!sshdr_external
)
2034 sshdr
= kzalloc(sizeof(*sshdr
), GFP_KERNEL
);
2036 sshdr
= sshdr_external
;
2038 /* try to eat the UNIT_ATTENTION if there are enough retries */
2040 result
= scsi_execute_req(sdev
, cmd
, DMA_NONE
, NULL
, 0, sshdr
,
2041 timeout
, retries
, NULL
);
2042 if (sdev
->removable
&& scsi_sense_valid(sshdr
) &&
2043 sshdr
->sense_key
== UNIT_ATTENTION
)
2045 } while (scsi_sense_valid(sshdr
) &&
2046 sshdr
->sense_key
== UNIT_ATTENTION
&& --retries
);
2048 if (!sshdr_external
)
2052 EXPORT_SYMBOL(scsi_test_unit_ready
);
2055 * scsi_device_set_state - Take the given device through the device state model.
2056 * @sdev: scsi device to change the state of.
2057 * @state: state to change to.
2059 * Returns zero if unsuccessful or an error if the requested
2060 * transition is illegal.
2063 scsi_device_set_state(struct scsi_device
*sdev
, enum scsi_device_state state
)
2065 enum scsi_device_state oldstate
= sdev
->sdev_state
;
2067 if (state
== oldstate
)
2073 case SDEV_CREATED_BLOCK
:
2117 case SDEV_CREATED_BLOCK
:
2124 case SDEV_CREATED_BLOCK
:
2159 sdev
->sdev_state
= state
;
2163 SCSI_LOG_ERROR_RECOVERY(1,
2164 sdev_printk(KERN_ERR
, sdev
,
2165 "Illegal state transition %s->%s\n",
2166 scsi_device_state_name(oldstate
),
2167 scsi_device_state_name(state
))
2171 EXPORT_SYMBOL(scsi_device_set_state
);
2174 * sdev_evt_emit - emit a single SCSI device uevent
2175 * @sdev: associated SCSI device
2176 * @evt: event to emit
2178 * Send a single uevent (scsi_event) to the associated scsi_device.
2180 static void scsi_evt_emit(struct scsi_device
*sdev
, struct scsi_event
*evt
)
2185 switch (evt
->evt_type
) {
2186 case SDEV_EVT_MEDIA_CHANGE
:
2187 envp
[idx
++] = "SDEV_MEDIA_CHANGE=1";
2197 kobject_uevent_env(&sdev
->sdev_gendev
.kobj
, KOBJ_CHANGE
, envp
);
2201 * sdev_evt_thread - send a uevent for each scsi event
2202 * @work: work struct for scsi_device
2204 * Dispatch queued events to their associated scsi_device kobjects
2207 void scsi_evt_thread(struct work_struct
*work
)
2209 struct scsi_device
*sdev
;
2210 LIST_HEAD(event_list
);
2212 sdev
= container_of(work
, struct scsi_device
, event_work
);
2215 struct scsi_event
*evt
;
2216 struct list_head
*this, *tmp
;
2217 unsigned long flags
;
2219 spin_lock_irqsave(&sdev
->list_lock
, flags
);
2220 list_splice_init(&sdev
->event_list
, &event_list
);
2221 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
2223 if (list_empty(&event_list
))
2226 list_for_each_safe(this, tmp
, &event_list
) {
2227 evt
= list_entry(this, struct scsi_event
, node
);
2228 list_del(&evt
->node
);
2229 scsi_evt_emit(sdev
, evt
);
2236 * sdev_evt_send - send asserted event to uevent thread
2237 * @sdev: scsi_device event occurred on
2238 * @evt: event to send
2240 * Assert scsi device event asynchronously.
2242 void sdev_evt_send(struct scsi_device
*sdev
, struct scsi_event
*evt
)
2244 unsigned long flags
;
2247 /* FIXME: currently this check eliminates all media change events
2248 * for polled devices. Need to update to discriminate between AN
2249 * and polled events */
2250 if (!test_bit(evt
->evt_type
, sdev
->supported_events
)) {
2256 spin_lock_irqsave(&sdev
->list_lock
, flags
);
2257 list_add_tail(&evt
->node
, &sdev
->event_list
);
2258 schedule_work(&sdev
->event_work
);
2259 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
2261 EXPORT_SYMBOL_GPL(sdev_evt_send
);
2264 * sdev_evt_alloc - allocate a new scsi event
2265 * @evt_type: type of event to allocate
2266 * @gfpflags: GFP flags for allocation
2268 * Allocates and returns a new scsi_event.
2270 struct scsi_event
*sdev_evt_alloc(enum scsi_device_event evt_type
,
2273 struct scsi_event
*evt
= kzalloc(sizeof(struct scsi_event
), gfpflags
);
2277 evt
->evt_type
= evt_type
;
2278 INIT_LIST_HEAD(&evt
->node
);
2280 /* evt_type-specific initialization, if any */
2282 case SDEV_EVT_MEDIA_CHANGE
:
2290 EXPORT_SYMBOL_GPL(sdev_evt_alloc
);
2293 * sdev_evt_send_simple - send asserted event to uevent thread
2294 * @sdev: scsi_device event occurred on
2295 * @evt_type: type of event to send
2296 * @gfpflags: GFP flags for allocation
2298 * Assert scsi device event asynchronously, given an event type.
2300 void sdev_evt_send_simple(struct scsi_device
*sdev
,
2301 enum scsi_device_event evt_type
, gfp_t gfpflags
)
2303 struct scsi_event
*evt
= sdev_evt_alloc(evt_type
, gfpflags
);
2305 sdev_printk(KERN_ERR
, sdev
, "event %d eaten due to OOM\n",
2310 sdev_evt_send(sdev
, evt
);
2312 EXPORT_SYMBOL_GPL(sdev_evt_send_simple
);
2315 * scsi_device_quiesce - Block user issued commands.
2316 * @sdev: scsi device to quiesce.
2318 * This works by trying to transition to the SDEV_QUIESCE state
2319 * (which must be a legal transition). When the device is in this
2320 * state, only special requests will be accepted, all others will
2321 * be deferred. Since special requests may also be requeued requests,
2322 * a successful return doesn't guarantee the device will be
2323 * totally quiescent.
2325 * Must be called with user context, may sleep.
2327 * Returns zero if unsuccessful or an error if not.
2330 scsi_device_quiesce(struct scsi_device
*sdev
)
2332 int err
= scsi_device_set_state(sdev
, SDEV_QUIESCE
);
2336 scsi_run_queue(sdev
->request_queue
);
2337 while (sdev
->device_busy
) {
2338 msleep_interruptible(200);
2339 scsi_run_queue(sdev
->request_queue
);
2343 EXPORT_SYMBOL(scsi_device_quiesce
);
2346 * scsi_device_resume - Restart user issued commands to a quiesced device.
2347 * @sdev: scsi device to resume.
2349 * Moves the device from quiesced back to running and restarts the
2352 * Must be called with user context, may sleep.
2355 scsi_device_resume(struct scsi_device
*sdev
)
2357 if(scsi_device_set_state(sdev
, SDEV_RUNNING
))
2359 scsi_run_queue(sdev
->request_queue
);
2361 EXPORT_SYMBOL(scsi_device_resume
);
2364 device_quiesce_fn(struct scsi_device
*sdev
, void *data
)
2366 scsi_device_quiesce(sdev
);
2370 scsi_target_quiesce(struct scsi_target
*starget
)
2372 starget_for_each_device(starget
, NULL
, device_quiesce_fn
);
2374 EXPORT_SYMBOL(scsi_target_quiesce
);
2377 device_resume_fn(struct scsi_device
*sdev
, void *data
)
2379 scsi_device_resume(sdev
);
2383 scsi_target_resume(struct scsi_target
*starget
)
2385 starget_for_each_device(starget
, NULL
, device_resume_fn
);
2387 EXPORT_SYMBOL(scsi_target_resume
);
2390 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state
2391 * @sdev: device to block
2393 * Block request made by scsi lld's to temporarily stop all
2394 * scsi commands on the specified device. Called from interrupt
2395 * or normal process context.
2397 * Returns zero if successful or error if not
2400 * This routine transitions the device to the SDEV_BLOCK state
2401 * (which must be a legal transition). When the device is in this
2402 * state, all commands are deferred until the scsi lld reenables
2403 * the device with scsi_device_unblock or device_block_tmo fires.
2404 * This routine assumes the host_lock is held on entry.
2407 scsi_internal_device_block(struct scsi_device
*sdev
)
2409 struct request_queue
*q
= sdev
->request_queue
;
2410 unsigned long flags
;
2413 err
= scsi_device_set_state(sdev
, SDEV_BLOCK
);
2415 err
= scsi_device_set_state(sdev
, SDEV_CREATED_BLOCK
);
2422 * The device has transitioned to SDEV_BLOCK. Stop the
2423 * block layer from calling the midlayer with this device's
2426 spin_lock_irqsave(q
->queue_lock
, flags
);
2428 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2432 EXPORT_SYMBOL_GPL(scsi_internal_device_block
);
2435 * scsi_internal_device_unblock - resume a device after a block request
2436 * @sdev: device to resume
2438 * Called by scsi lld's or the midlayer to restart the device queue
2439 * for the previously suspended scsi device. Called from interrupt or
2440 * normal process context.
2442 * Returns zero if successful or error if not.
2445 * This routine transitions the device to the SDEV_RUNNING state
2446 * (which must be a legal transition) allowing the midlayer to
2447 * goose the queue for this device. This routine assumes the
2448 * host_lock is held upon entry.
2451 scsi_internal_device_unblock(struct scsi_device
*sdev
)
2453 struct request_queue
*q
= sdev
->request_queue
;
2454 unsigned long flags
;
2457 * Try to transition the scsi device to SDEV_RUNNING
2458 * and goose the device queue if successful.
2460 if (sdev
->sdev_state
== SDEV_BLOCK
)
2461 sdev
->sdev_state
= SDEV_RUNNING
;
2462 else if (sdev
->sdev_state
== SDEV_CREATED_BLOCK
)
2463 sdev
->sdev_state
= SDEV_CREATED
;
2464 else if (sdev
->sdev_state
!= SDEV_CANCEL
&&
2465 sdev
->sdev_state
!= SDEV_OFFLINE
)
2468 spin_lock_irqsave(q
->queue_lock
, flags
);
2470 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2474 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock
);
2477 device_block(struct scsi_device
*sdev
, void *data
)
2479 scsi_internal_device_block(sdev
);
2483 target_block(struct device
*dev
, void *data
)
2485 if (scsi_is_target_device(dev
))
2486 starget_for_each_device(to_scsi_target(dev
), NULL
,
2492 scsi_target_block(struct device
*dev
)
2494 if (scsi_is_target_device(dev
))
2495 starget_for_each_device(to_scsi_target(dev
), NULL
,
2498 device_for_each_child(dev
, NULL
, target_block
);
2500 EXPORT_SYMBOL_GPL(scsi_target_block
);
2503 device_unblock(struct scsi_device
*sdev
, void *data
)
2505 scsi_internal_device_unblock(sdev
);
2509 target_unblock(struct device
*dev
, void *data
)
2511 if (scsi_is_target_device(dev
))
2512 starget_for_each_device(to_scsi_target(dev
), NULL
,
2518 scsi_target_unblock(struct device
*dev
)
2520 if (scsi_is_target_device(dev
))
2521 starget_for_each_device(to_scsi_target(dev
), NULL
,
2524 device_for_each_child(dev
, NULL
, target_unblock
);
2526 EXPORT_SYMBOL_GPL(scsi_target_unblock
);
2529 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
2530 * @sgl: scatter-gather list
2531 * @sg_count: number of segments in sg
2532 * @offset: offset in bytes into sg, on return offset into the mapped area
2533 * @len: bytes to map, on return number of bytes mapped
2535 * Returns virtual address of the start of the mapped page
2537 void *scsi_kmap_atomic_sg(struct scatterlist
*sgl
, int sg_count
,
2538 size_t *offset
, size_t *len
)
2541 size_t sg_len
= 0, len_complete
= 0;
2542 struct scatterlist
*sg
;
2545 WARN_ON(!irqs_disabled());
2547 for_each_sg(sgl
, sg
, sg_count
, i
) {
2548 len_complete
= sg_len
; /* Complete sg-entries */
2549 sg_len
+= sg
->length
;
2550 if (sg_len
> *offset
)
2554 if (unlikely(i
== sg_count
)) {
2555 printk(KERN_ERR
"%s: Bytes in sg: %zu, requested offset %zu, "
2557 __func__
, sg_len
, *offset
, sg_count
);
2562 /* Offset starting from the beginning of first page in this sg-entry */
2563 *offset
= *offset
- len_complete
+ sg
->offset
;
2565 /* Assumption: contiguous pages can be accessed as "page + i" */
2566 page
= nth_page(sg_page(sg
), (*offset
>> PAGE_SHIFT
));
2567 *offset
&= ~PAGE_MASK
;
2569 /* Bytes in this sg-entry from *offset to the end of the page */
2570 sg_len
= PAGE_SIZE
- *offset
;
2574 return kmap_atomic(page
, KM_BIO_SRC_IRQ
);
2576 EXPORT_SYMBOL(scsi_kmap_atomic_sg
);
2579 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
2580 * @virt: virtual address to be unmapped
2582 void scsi_kunmap_atomic_sg(void *virt
)
2584 kunmap_atomic(virt
, KM_BIO_SRC_IRQ
);
2586 EXPORT_SYMBOL(scsi_kunmap_atomic_sg
);