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 #include <acpi/acpi_bus.h>
74 static bool acpi_scsi_bus_match(struct device
*dev
)
76 return dev
->bus
== &scsi_bus_type
;
79 int scsi_register_acpi_bus_type(struct acpi_bus_type
*bus
)
81 bus
->match
= acpi_scsi_bus_match
;
82 return register_acpi_bus_type(bus
);
84 EXPORT_SYMBOL_GPL(scsi_register_acpi_bus_type
);
86 void scsi_unregister_acpi_bus_type(struct acpi_bus_type
*bus
)
88 unregister_acpi_bus_type(bus
);
90 EXPORT_SYMBOL_GPL(scsi_unregister_acpi_bus_type
);
94 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
95 * not change behaviour from the previous unplug mechanism, experimentation
96 * may prove this needs changing.
98 #define SCSI_QUEUE_DELAY 3
101 * Function: scsi_unprep_request()
103 * Purpose: Remove all preparation done for a request, including its
104 * associated scsi_cmnd, so that it can be requeued.
106 * Arguments: req - request to unprepare
108 * Lock status: Assumed that no locks are held upon entry.
112 static void scsi_unprep_request(struct request
*req
)
114 struct scsi_cmnd
*cmd
= req
->special
;
116 blk_unprep_request(req
);
119 scsi_put_command(cmd
);
123 * __scsi_queue_insert - private queue insertion
124 * @cmd: The SCSI command being requeued
125 * @reason: The reason for the requeue
126 * @unbusy: Whether the queue should be unbusied
128 * This is a private queue insertion. The public interface
129 * scsi_queue_insert() always assumes the queue should be unbusied
130 * because it's always called before the completion. This function is
131 * for a requeue after completion, which should only occur in this
134 static void __scsi_queue_insert(struct scsi_cmnd
*cmd
, int reason
, int unbusy
)
136 struct Scsi_Host
*host
= cmd
->device
->host
;
137 struct scsi_device
*device
= cmd
->device
;
138 struct scsi_target
*starget
= scsi_target(device
);
139 struct request_queue
*q
= device
->request_queue
;
143 printk("Inserting command %p into mlqueue\n", cmd
));
146 * Set the appropriate busy bit for the device/host.
148 * If the host/device isn't busy, assume that something actually
149 * completed, and that we should be able to queue a command now.
151 * Note that the prior mid-layer assumption that any host could
152 * always queue at least one command is now broken. The mid-layer
153 * will implement a user specifiable stall (see
154 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
155 * if a command is requeued with no other commands outstanding
156 * either for the device or for the host.
159 case SCSI_MLQUEUE_HOST_BUSY
:
160 host
->host_blocked
= host
->max_host_blocked
;
162 case SCSI_MLQUEUE_DEVICE_BUSY
:
163 case SCSI_MLQUEUE_EH_RETRY
:
164 device
->device_blocked
= device
->max_device_blocked
;
166 case SCSI_MLQUEUE_TARGET_BUSY
:
167 starget
->target_blocked
= starget
->max_target_blocked
;
172 * Decrement the counters, since these commands are no longer
173 * active on the host/device.
176 scsi_device_unbusy(device
);
179 * Requeue this command. It will go before all other commands
180 * that are already in the queue. Schedule requeue work under
181 * lock such that the kblockd_schedule_work() call happens
182 * before blk_cleanup_queue() finishes.
184 spin_lock_irqsave(q
->queue_lock
, flags
);
185 blk_requeue_request(q
, cmd
->request
);
186 kblockd_schedule_work(q
, &device
->requeue_work
);
187 spin_unlock_irqrestore(q
->queue_lock
, flags
);
191 * Function: scsi_queue_insert()
193 * Purpose: Insert a command in the midlevel queue.
195 * Arguments: cmd - command that we are adding to queue.
196 * reason - why we are inserting command to queue.
198 * Lock status: Assumed that lock is not held upon entry.
202 * Notes: We do this for one of two cases. Either the host is busy
203 * and it cannot accept any more commands for the time being,
204 * or the device returned QUEUE_FULL and can accept no more
206 * Notes: This could be called either from an interrupt context or a
207 * normal process context.
209 void scsi_queue_insert(struct scsi_cmnd
*cmd
, int reason
)
211 __scsi_queue_insert(cmd
, reason
, 1);
214 * scsi_execute - insert request and wait for the result
217 * @data_direction: data direction
218 * @buffer: data buffer
219 * @bufflen: len of buffer
220 * @sense: optional sense buffer
221 * @timeout: request timeout in seconds
222 * @retries: number of times to retry request
223 * @flags: or into request flags;
224 * @resid: optional residual length
226 * returns the req->errors value which is the scsi_cmnd result
229 int scsi_execute(struct scsi_device
*sdev
, const unsigned char *cmd
,
230 int data_direction
, void *buffer
, unsigned bufflen
,
231 unsigned char *sense
, int timeout
, int retries
, int flags
,
235 int write
= (data_direction
== DMA_TO_DEVICE
);
236 int ret
= DRIVER_ERROR
<< 24;
238 req
= blk_get_request(sdev
->request_queue
, write
, __GFP_WAIT
);
242 if (bufflen
&& blk_rq_map_kern(sdev
->request_queue
, req
,
243 buffer
, bufflen
, __GFP_WAIT
))
246 req
->cmd_len
= COMMAND_SIZE(cmd
[0]);
247 memcpy(req
->cmd
, cmd
, req
->cmd_len
);
250 req
->retries
= retries
;
251 req
->timeout
= timeout
;
252 req
->cmd_type
= REQ_TYPE_BLOCK_PC
;
253 req
->cmd_flags
|= flags
| REQ_QUIET
| REQ_PREEMPT
;
256 * head injection *required* here otherwise quiesce won't work
258 blk_execute_rq(req
->q
, NULL
, req
, 1);
261 * Some devices (USB mass-storage in particular) may transfer
262 * garbage data together with a residue indicating that the data
263 * is invalid. Prevent the garbage from being misinterpreted
264 * and prevent security leaks by zeroing out the excess data.
266 if (unlikely(req
->resid_len
> 0 && req
->resid_len
<= bufflen
))
267 memset(buffer
+ (bufflen
- req
->resid_len
), 0, req
->resid_len
);
270 *resid
= req
->resid_len
;
273 blk_put_request(req
);
277 EXPORT_SYMBOL(scsi_execute
);
279 int scsi_execute_req_flags(struct scsi_device
*sdev
, const unsigned char *cmd
,
280 int data_direction
, void *buffer
, unsigned bufflen
,
281 struct scsi_sense_hdr
*sshdr
, int timeout
, int retries
,
282 int *resid
, int flags
)
288 sense
= kzalloc(SCSI_SENSE_BUFFERSIZE
, GFP_NOIO
);
290 return DRIVER_ERROR
<< 24;
292 result
= scsi_execute(sdev
, cmd
, data_direction
, buffer
, bufflen
,
293 sense
, timeout
, retries
, flags
, resid
);
295 scsi_normalize_sense(sense
, SCSI_SENSE_BUFFERSIZE
, sshdr
);
300 EXPORT_SYMBOL(scsi_execute_req_flags
);
303 * Function: scsi_init_cmd_errh()
305 * Purpose: Initialize cmd fields related to error handling.
307 * Arguments: cmd - command that is ready to be queued.
309 * Notes: This function has the job of initializing a number of
310 * fields related to error handling. Typically this will
311 * be called once for each command, as required.
313 static void scsi_init_cmd_errh(struct scsi_cmnd
*cmd
)
315 cmd
->serial_number
= 0;
316 scsi_set_resid(cmd
, 0);
317 memset(cmd
->sense_buffer
, 0, SCSI_SENSE_BUFFERSIZE
);
318 if (cmd
->cmd_len
== 0)
319 cmd
->cmd_len
= scsi_command_size(cmd
->cmnd
);
322 void scsi_device_unbusy(struct scsi_device
*sdev
)
324 struct Scsi_Host
*shost
= sdev
->host
;
325 struct scsi_target
*starget
= scsi_target(sdev
);
328 spin_lock_irqsave(shost
->host_lock
, flags
);
330 starget
->target_busy
--;
331 if (unlikely(scsi_host_in_recovery(shost
) &&
332 (shost
->host_failed
|| shost
->host_eh_scheduled
)))
333 scsi_eh_wakeup(shost
);
334 spin_unlock(shost
->host_lock
);
335 spin_lock(sdev
->request_queue
->queue_lock
);
337 spin_unlock_irqrestore(sdev
->request_queue
->queue_lock
, flags
);
341 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
342 * and call blk_run_queue for all the scsi_devices on the target -
343 * including current_sdev first.
345 * Called with *no* scsi locks held.
347 static void scsi_single_lun_run(struct scsi_device
*current_sdev
)
349 struct Scsi_Host
*shost
= current_sdev
->host
;
350 struct scsi_device
*sdev
, *tmp
;
351 struct scsi_target
*starget
= scsi_target(current_sdev
);
354 spin_lock_irqsave(shost
->host_lock
, flags
);
355 starget
->starget_sdev_user
= NULL
;
356 spin_unlock_irqrestore(shost
->host_lock
, flags
);
359 * Call blk_run_queue for all LUNs on the target, starting with
360 * current_sdev. We race with others (to set starget_sdev_user),
361 * but in most cases, we will be first. Ideally, each LU on the
362 * target would get some limited time or requests on the target.
364 blk_run_queue(current_sdev
->request_queue
);
366 spin_lock_irqsave(shost
->host_lock
, flags
);
367 if (starget
->starget_sdev_user
)
369 list_for_each_entry_safe(sdev
, tmp
, &starget
->devices
,
370 same_target_siblings
) {
371 if (sdev
== current_sdev
)
373 if (scsi_device_get(sdev
))
376 spin_unlock_irqrestore(shost
->host_lock
, flags
);
377 blk_run_queue(sdev
->request_queue
);
378 spin_lock_irqsave(shost
->host_lock
, flags
);
380 scsi_device_put(sdev
);
383 spin_unlock_irqrestore(shost
->host_lock
, flags
);
386 static inline int scsi_device_is_busy(struct scsi_device
*sdev
)
388 if (sdev
->device_busy
>= sdev
->queue_depth
|| sdev
->device_blocked
)
394 static inline int scsi_target_is_busy(struct scsi_target
*starget
)
396 return ((starget
->can_queue
> 0 &&
397 starget
->target_busy
>= starget
->can_queue
) ||
398 starget
->target_blocked
);
401 static inline int scsi_host_is_busy(struct Scsi_Host
*shost
)
403 if ((shost
->can_queue
> 0 && shost
->host_busy
>= shost
->can_queue
) ||
404 shost
->host_blocked
|| shost
->host_self_blocked
)
411 * Function: scsi_run_queue()
413 * Purpose: Select a proper request queue to serve next
415 * Arguments: q - last request's queue
419 * Notes: The previous command was completely finished, start
420 * a new one if possible.
422 static void scsi_run_queue(struct request_queue
*q
)
424 struct scsi_device
*sdev
= q
->queuedata
;
425 struct Scsi_Host
*shost
;
426 LIST_HEAD(starved_list
);
430 if (scsi_target(sdev
)->single_lun
)
431 scsi_single_lun_run(sdev
);
433 spin_lock_irqsave(shost
->host_lock
, flags
);
434 list_splice_init(&shost
->starved_list
, &starved_list
);
436 while (!list_empty(&starved_list
)) {
438 * As long as shost is accepting commands and we have
439 * starved queues, call blk_run_queue. scsi_request_fn
440 * drops the queue_lock and can add us back to the
443 * host_lock protects the starved_list and starved_entry.
444 * scsi_request_fn must get the host_lock before checking
445 * or modifying starved_list or starved_entry.
447 if (scsi_host_is_busy(shost
))
450 sdev
= list_entry(starved_list
.next
,
451 struct scsi_device
, starved_entry
);
452 list_del_init(&sdev
->starved_entry
);
453 if (scsi_target_is_busy(scsi_target(sdev
))) {
454 list_move_tail(&sdev
->starved_entry
,
455 &shost
->starved_list
);
459 spin_unlock(shost
->host_lock
);
460 spin_lock(sdev
->request_queue
->queue_lock
);
461 __blk_run_queue(sdev
->request_queue
);
462 spin_unlock(sdev
->request_queue
->queue_lock
);
463 spin_lock(shost
->host_lock
);
465 /* put any unprocessed entries back */
466 list_splice(&starved_list
, &shost
->starved_list
);
467 spin_unlock_irqrestore(shost
->host_lock
, flags
);
472 void scsi_requeue_run_queue(struct work_struct
*work
)
474 struct scsi_device
*sdev
;
475 struct request_queue
*q
;
477 sdev
= container_of(work
, struct scsi_device
, requeue_work
);
478 q
= sdev
->request_queue
;
483 * Function: scsi_requeue_command()
485 * Purpose: Handle post-processing of completed commands.
487 * Arguments: q - queue to operate on
488 * cmd - command that may need to be requeued.
492 * Notes: After command completion, there may be blocks left
493 * over which weren't finished by the previous command
494 * this can be for a number of reasons - the main one is
495 * I/O errors in the middle of the request, in which case
496 * we need to request the blocks that come after the bad
498 * Notes: Upon return, cmd is a stale pointer.
500 static void scsi_requeue_command(struct request_queue
*q
, struct scsi_cmnd
*cmd
)
502 struct scsi_device
*sdev
= cmd
->device
;
503 struct request
*req
= cmd
->request
;
507 * We need to hold a reference on the device to avoid the queue being
508 * killed after the unlock and before scsi_run_queue is invoked which
509 * may happen because scsi_unprep_request() puts the command which
510 * releases its reference on the device.
512 get_device(&sdev
->sdev_gendev
);
514 spin_lock_irqsave(q
->queue_lock
, flags
);
515 scsi_unprep_request(req
);
516 blk_requeue_request(q
, req
);
517 spin_unlock_irqrestore(q
->queue_lock
, flags
);
521 put_device(&sdev
->sdev_gendev
);
524 void scsi_next_command(struct scsi_cmnd
*cmd
)
526 struct scsi_device
*sdev
= cmd
->device
;
527 struct request_queue
*q
= sdev
->request_queue
;
529 /* need to hold a reference on the device before we let go of the cmd */
530 get_device(&sdev
->sdev_gendev
);
532 scsi_put_command(cmd
);
535 /* ok to remove device now */
536 put_device(&sdev
->sdev_gendev
);
539 void scsi_run_host_queues(struct Scsi_Host
*shost
)
541 struct scsi_device
*sdev
;
543 shost_for_each_device(sdev
, shost
)
544 scsi_run_queue(sdev
->request_queue
);
547 static void __scsi_release_buffers(struct scsi_cmnd
*, int);
549 static inline unsigned int scsi_sgtable_index(unsigned short nents
)
553 BUG_ON(nents
> SCSI_MAX_SG_SEGMENTS
);
558 index
= get_count_order(nents
) - 3;
563 static void scsi_sg_free(struct scatterlist
*sgl
, unsigned int nents
)
565 struct scsi_host_sg_pool
*sgp
;
567 sgp
= scsi_sg_pools
+ scsi_sgtable_index(nents
);
568 mempool_free(sgl
, sgp
->pool
);
571 static struct scatterlist
*scsi_sg_alloc(unsigned int nents
, gfp_t gfp_mask
)
573 struct scsi_host_sg_pool
*sgp
;
575 sgp
= scsi_sg_pools
+ scsi_sgtable_index(nents
);
576 return mempool_alloc(sgp
->pool
, gfp_mask
);
579 static int scsi_alloc_sgtable(struct scsi_data_buffer
*sdb
, int nents
,
586 ret
= __sg_alloc_table(&sdb
->table
, nents
, SCSI_MAX_SG_SEGMENTS
,
587 gfp_mask
, scsi_sg_alloc
);
589 __sg_free_table(&sdb
->table
, SCSI_MAX_SG_SEGMENTS
,
595 static void scsi_free_sgtable(struct scsi_data_buffer
*sdb
)
597 __sg_free_table(&sdb
->table
, SCSI_MAX_SG_SEGMENTS
, scsi_sg_free
);
600 static void __scsi_release_buffers(struct scsi_cmnd
*cmd
, int do_bidi_check
)
603 if (cmd
->sdb
.table
.nents
)
604 scsi_free_sgtable(&cmd
->sdb
);
606 memset(&cmd
->sdb
, 0, sizeof(cmd
->sdb
));
608 if (do_bidi_check
&& scsi_bidi_cmnd(cmd
)) {
609 struct scsi_data_buffer
*bidi_sdb
=
610 cmd
->request
->next_rq
->special
;
611 scsi_free_sgtable(bidi_sdb
);
612 kmem_cache_free(scsi_sdb_cache
, bidi_sdb
);
613 cmd
->request
->next_rq
->special
= NULL
;
616 if (scsi_prot_sg_count(cmd
))
617 scsi_free_sgtable(cmd
->prot_sdb
);
621 * Function: scsi_release_buffers()
623 * Purpose: Completion processing for block device I/O requests.
625 * Arguments: cmd - command that we are bailing.
627 * Lock status: Assumed that no lock is held upon entry.
631 * Notes: In the event that an upper level driver rejects a
632 * command, we must release resources allocated during
633 * the __init_io() function. Primarily this would involve
634 * the scatter-gather table, and potentially any bounce
637 void scsi_release_buffers(struct scsi_cmnd
*cmd
)
639 __scsi_release_buffers(cmd
, 1);
641 EXPORT_SYMBOL(scsi_release_buffers
);
643 static int __scsi_error_from_host_byte(struct scsi_cmnd
*cmd
, int result
)
647 switch(host_byte(result
)) {
648 case DID_TRANSPORT_FAILFAST
:
651 case DID_TARGET_FAILURE
:
652 set_host_byte(cmd
, DID_OK
);
655 case DID_NEXUS_FAILURE
:
656 set_host_byte(cmd
, DID_OK
);
668 * Function: scsi_io_completion()
670 * Purpose: Completion processing for block device I/O requests.
672 * Arguments: cmd - command that is finished.
674 * Lock status: Assumed that no lock is held upon entry.
678 * Notes: We will finish off the specified number of sectors. If we
679 * are done, the command block will be released and the queue
680 * function will be goosed. If we are not done then we have to
681 * figure out what to do next:
683 * a) We can call scsi_requeue_command(). The request
684 * will be unprepared and put back on the queue. Then
685 * a new command will be created for it. This should
686 * be used if we made forward progress, or if we want
687 * to switch from READ(10) to READ(6) for example.
689 * b) We can call __scsi_queue_insert(). The request will
690 * be put back on the queue and retried using the same
691 * command as before, possibly after a delay.
693 * c) We can call blk_end_request() with -EIO to fail
694 * the remainder of the request.
696 void scsi_io_completion(struct scsi_cmnd
*cmd
, unsigned int good_bytes
)
698 int result
= cmd
->result
;
699 struct request_queue
*q
= cmd
->device
->request_queue
;
700 struct request
*req
= cmd
->request
;
702 struct scsi_sense_hdr sshdr
;
704 int sense_deferred
= 0;
705 enum {ACTION_FAIL
, ACTION_REPREP
, ACTION_RETRY
,
706 ACTION_DELAYED_RETRY
} action
;
707 char *description
= NULL
;
710 sense_valid
= scsi_command_normalize_sense(cmd
, &sshdr
);
712 sense_deferred
= scsi_sense_is_deferred(&sshdr
);
715 if (req
->cmd_type
== REQ_TYPE_BLOCK_PC
) { /* SG_IO ioctl from block level */
717 if (sense_valid
&& req
->sense
) {
719 * SG_IO wants current and deferred errors
721 int len
= 8 + cmd
->sense_buffer
[7];
723 if (len
> SCSI_SENSE_BUFFERSIZE
)
724 len
= SCSI_SENSE_BUFFERSIZE
;
725 memcpy(req
->sense
, cmd
->sense_buffer
, len
);
726 req
->sense_len
= len
;
729 error
= __scsi_error_from_host_byte(cmd
, result
);
732 * __scsi_error_from_host_byte may have reset the host_byte
734 req
->errors
= cmd
->result
;
736 req
->resid_len
= scsi_get_resid(cmd
);
738 if (scsi_bidi_cmnd(cmd
)) {
740 * Bidi commands Must be complete as a whole,
741 * both sides at once.
743 req
->next_rq
->resid_len
= scsi_in(cmd
)->resid
;
745 scsi_release_buffers(cmd
);
746 blk_end_request_all(req
, 0);
748 scsi_next_command(cmd
);
751 } else if (blk_rq_bytes(req
) == 0 && result
&& !sense_deferred
) {
753 * Certain non BLOCK_PC requests are commands that don't
754 * actually transfer anything (FLUSH), so cannot use
755 * good_bytes != blk_rq_bytes(req) as the signal for an error.
756 * This sets the error explicitly for the problem case.
758 error
= __scsi_error_from_host_byte(cmd
, result
);
761 /* no bidi support for !REQ_TYPE_BLOCK_PC yet */
762 BUG_ON(blk_bidi_rq(req
));
765 * Next deal with any sectors which we were able to correctly
768 SCSI_LOG_HLCOMPLETE(1, printk("%u sectors total, "
770 blk_rq_sectors(req
), good_bytes
));
773 * Recovered errors need reporting, but they're always treated
774 * as success, so fiddle the result code here. For BLOCK_PC
775 * we already took a copy of the original into rq->errors which
776 * is what gets returned to the user
778 if (sense_valid
&& (sshdr
.sense_key
== RECOVERED_ERROR
)) {
779 /* if ATA PASS-THROUGH INFORMATION AVAILABLE skip
780 * print since caller wants ATA registers. Only occurs on
781 * SCSI ATA PASS_THROUGH commands when CK_COND=1
783 if ((sshdr
.asc
== 0x0) && (sshdr
.ascq
== 0x1d))
785 else if (!(req
->cmd_flags
& REQ_QUIET
))
786 scsi_print_sense("", cmd
);
788 /* BLOCK_PC may have set error */
793 * special case: failed zero length commands always need to
794 * drop down into the retry code. Otherwise, if we finished
795 * all bytes in the request we are done now.
797 if (!(blk_rq_bytes(req
) == 0 && error
) &&
798 !blk_end_request(req
, error
, good_bytes
))
802 * Kill remainder if no retrys.
804 if (error
&& scsi_noretry_cmd(cmd
)) {
805 blk_end_request_all(req
, error
);
810 * If there had been no error, but we have leftover bytes in the
811 * requeues just queue the command up again.
816 error
= __scsi_error_from_host_byte(cmd
, result
);
818 if (host_byte(result
) == DID_RESET
) {
819 /* Third party bus reset or reset for error recovery
820 * reasons. Just retry the command and see what
823 action
= ACTION_RETRY
;
824 } else if (sense_valid
&& !sense_deferred
) {
825 switch (sshdr
.sense_key
) {
827 if (cmd
->device
->removable
) {
828 /* Detected disc change. Set a bit
829 * and quietly refuse further access.
831 cmd
->device
->changed
= 1;
832 description
= "Media Changed";
833 action
= ACTION_FAIL
;
835 /* Must have been a power glitch, or a
836 * bus reset. Could not have been a
837 * media change, so we just retry the
838 * command and see what happens.
840 action
= ACTION_RETRY
;
843 case ILLEGAL_REQUEST
:
844 /* If we had an ILLEGAL REQUEST returned, then
845 * we may have performed an unsupported
846 * command. The only thing this should be
847 * would be a ten byte read where only a six
848 * byte read was supported. Also, on a system
849 * where READ CAPACITY failed, we may have
850 * read past the end of the disk.
852 if ((cmd
->device
->use_10_for_rw
&&
853 sshdr
.asc
== 0x20 && sshdr
.ascq
== 0x00) &&
854 (cmd
->cmnd
[0] == READ_10
||
855 cmd
->cmnd
[0] == WRITE_10
)) {
856 /* This will issue a new 6-byte command. */
857 cmd
->device
->use_10_for_rw
= 0;
858 action
= ACTION_REPREP
;
859 } else if (sshdr
.asc
== 0x10) /* DIX */ {
860 description
= "Host Data Integrity Failure";
861 action
= ACTION_FAIL
;
863 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
864 } else if (sshdr
.asc
== 0x20 || sshdr
.asc
== 0x24) {
865 switch (cmd
->cmnd
[0]) {
867 description
= "Discard failure";
871 if (cmd
->cmnd
[1] & 0x8)
872 description
= "Discard failure";
875 "Write same failure";
878 description
= "Invalid command failure";
881 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 if (!(req
->cmd_flags
& REQ_QUIET
)) {
938 scmd_printk(KERN_INFO
, cmd
, "%s\n",
940 scsi_print_result(cmd
);
941 if (driver_byte(result
) & DRIVER_SENSE
)
942 scsi_print_sense("", cmd
);
943 scsi_print_command(cmd
);
945 if (!blk_end_request_err(req
, error
))
950 /* Unprep the request and put it back at the head of the queue.
951 * A new command will be prepared and issued.
953 scsi_release_buffers(cmd
);
954 scsi_requeue_command(q
, cmd
);
957 /* Retry the same command immediately */
958 __scsi_queue_insert(cmd
, SCSI_MLQUEUE_EH_RETRY
, 0);
960 case ACTION_DELAYED_RETRY
:
961 /* Retry the same command after a delay */
962 __scsi_queue_insert(cmd
, SCSI_MLQUEUE_DEVICE_BUSY
, 0);
968 __scsi_release_buffers(cmd
, 0);
969 scsi_next_command(cmd
);
972 static int scsi_init_sgtable(struct request
*req
, struct scsi_data_buffer
*sdb
,
978 * If sg table allocation fails, requeue request later.
980 if (unlikely(scsi_alloc_sgtable(sdb
, req
->nr_phys_segments
,
982 return BLKPREP_DEFER
;
988 * Next, walk the list, and fill in the addresses and sizes of
991 count
= blk_rq_map_sg(req
->q
, req
, sdb
->table
.sgl
);
992 BUG_ON(count
> sdb
->table
.nents
);
993 sdb
->table
.nents
= count
;
994 sdb
->length
= blk_rq_bytes(req
);
999 * Function: scsi_init_io()
1001 * Purpose: SCSI I/O initialize function.
1003 * Arguments: cmd - Command descriptor we wish to initialize
1005 * Returns: 0 on success
1006 * BLKPREP_DEFER if the failure is retryable
1007 * BLKPREP_KILL if the failure is fatal
1009 int scsi_init_io(struct scsi_cmnd
*cmd
, gfp_t gfp_mask
)
1011 struct request
*rq
= cmd
->request
;
1014 if (WARN_ON_ONCE(!rq
->nr_phys_segments
))
1017 error
= scsi_init_sgtable(rq
, &cmd
->sdb
, gfp_mask
);
1021 if (blk_bidi_rq(rq
)) {
1022 struct scsi_data_buffer
*bidi_sdb
= kmem_cache_zalloc(
1023 scsi_sdb_cache
, GFP_ATOMIC
);
1025 error
= BLKPREP_DEFER
;
1029 rq
->next_rq
->special
= bidi_sdb
;
1030 error
= scsi_init_sgtable(rq
->next_rq
, bidi_sdb
, GFP_ATOMIC
);
1035 if (blk_integrity_rq(rq
)) {
1036 struct scsi_data_buffer
*prot_sdb
= cmd
->prot_sdb
;
1039 BUG_ON(prot_sdb
== NULL
);
1040 ivecs
= blk_rq_count_integrity_sg(rq
->q
, rq
->bio
);
1042 if (scsi_alloc_sgtable(prot_sdb
, ivecs
, gfp_mask
)) {
1043 error
= BLKPREP_DEFER
;
1047 count
= blk_rq_map_integrity_sg(rq
->q
, rq
->bio
,
1048 prot_sdb
->table
.sgl
);
1049 BUG_ON(unlikely(count
> ivecs
));
1050 BUG_ON(unlikely(count
> queue_max_integrity_segments(rq
->q
)));
1052 cmd
->prot_sdb
= prot_sdb
;
1053 cmd
->prot_sdb
->table
.nents
= count
;
1059 scsi_release_buffers(cmd
);
1060 cmd
->request
->special
= NULL
;
1061 scsi_put_command(cmd
);
1064 EXPORT_SYMBOL(scsi_init_io
);
1066 static struct scsi_cmnd
*scsi_get_cmd_from_req(struct scsi_device
*sdev
,
1067 struct request
*req
)
1069 struct scsi_cmnd
*cmd
;
1071 if (!req
->special
) {
1072 cmd
= scsi_get_command(sdev
, GFP_ATOMIC
);
1080 /* pull a tag out of the request if we have one */
1081 cmd
->tag
= req
->tag
;
1084 cmd
->cmnd
= req
->cmd
;
1085 cmd
->prot_op
= SCSI_PROT_NORMAL
;
1090 int scsi_setup_blk_pc_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1092 struct scsi_cmnd
*cmd
;
1093 int ret
= scsi_prep_state_check(sdev
, req
);
1095 if (ret
!= BLKPREP_OK
)
1098 cmd
= scsi_get_cmd_from_req(sdev
, req
);
1100 return BLKPREP_DEFER
;
1103 * BLOCK_PC requests may transfer data, in which case they must
1104 * a bio attached to them. Or they might contain a SCSI command
1105 * that does not transfer data, in which case they may optionally
1106 * submit a request without an attached bio.
1109 int ret
= scsi_init_io(cmd
, GFP_ATOMIC
);
1113 BUG_ON(blk_rq_bytes(req
));
1115 memset(&cmd
->sdb
, 0, sizeof(cmd
->sdb
));
1119 cmd
->cmd_len
= req
->cmd_len
;
1120 if (!blk_rq_bytes(req
))
1121 cmd
->sc_data_direction
= DMA_NONE
;
1122 else if (rq_data_dir(req
) == WRITE
)
1123 cmd
->sc_data_direction
= DMA_TO_DEVICE
;
1125 cmd
->sc_data_direction
= DMA_FROM_DEVICE
;
1127 cmd
->transfersize
= blk_rq_bytes(req
);
1128 cmd
->allowed
= req
->retries
;
1131 EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd
);
1134 * Setup a REQ_TYPE_FS command. These are simple read/write request
1135 * from filesystems that still need to be translated to SCSI CDBs from
1138 int scsi_setup_fs_cmnd(struct scsi_device
*sdev
, struct request
*req
)
1140 struct scsi_cmnd
*cmd
;
1141 int ret
= scsi_prep_state_check(sdev
, req
);
1143 if (ret
!= BLKPREP_OK
)
1146 if (unlikely(sdev
->scsi_dh_data
&& sdev
->scsi_dh_data
->scsi_dh
1147 && sdev
->scsi_dh_data
->scsi_dh
->prep_fn
)) {
1148 ret
= sdev
->scsi_dh_data
->scsi_dh
->prep_fn(sdev
, req
);
1149 if (ret
!= BLKPREP_OK
)
1153 cmd
= scsi_get_cmd_from_req(sdev
, req
);
1155 return BLKPREP_DEFER
;
1157 memset(cmd
->cmnd
, 0, BLK_MAX_CDB
);
1158 return scsi_init_io(cmd
, GFP_ATOMIC
);
1160 EXPORT_SYMBOL(scsi_setup_fs_cmnd
);
1162 int scsi_prep_state_check(struct scsi_device
*sdev
, struct request
*req
)
1164 int ret
= BLKPREP_OK
;
1167 * If the device is not in running state we will reject some
1170 if (unlikely(sdev
->sdev_state
!= SDEV_RUNNING
)) {
1171 switch (sdev
->sdev_state
) {
1173 case SDEV_TRANSPORT_OFFLINE
:
1175 * If the device is offline we refuse to process any
1176 * commands. The device must be brought online
1177 * before trying any recovery commands.
1179 sdev_printk(KERN_ERR
, sdev
,
1180 "rejecting I/O to offline device\n");
1185 * If the device is fully deleted, we refuse to
1186 * process any commands as well.
1188 sdev_printk(KERN_ERR
, sdev
,
1189 "rejecting I/O to dead device\n");
1193 case SDEV_CREATED_BLOCK
:
1194 ret
= BLKPREP_DEFER
;
1198 * If the devices is blocked we defer normal commands.
1200 if (!(req
->cmd_flags
& REQ_PREEMPT
))
1201 ret
= BLKPREP_DEFER
;
1205 * For any other not fully online state we only allow
1206 * special commands. In particular any user initiated
1207 * command is not allowed.
1209 if (!(req
->cmd_flags
& REQ_PREEMPT
))
1216 EXPORT_SYMBOL(scsi_prep_state_check
);
1218 int scsi_prep_return(struct request_queue
*q
, struct request
*req
, int ret
)
1220 struct scsi_device
*sdev
= q
->queuedata
;
1224 req
->errors
= DID_NO_CONNECT
<< 16;
1225 /* release the command and kill it */
1227 struct scsi_cmnd
*cmd
= req
->special
;
1228 scsi_release_buffers(cmd
);
1229 scsi_put_command(cmd
);
1230 req
->special
= NULL
;
1235 * If we defer, the blk_peek_request() returns NULL, but the
1236 * queue must be restarted, so we schedule a callback to happen
1239 if (sdev
->device_busy
== 0)
1240 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1243 req
->cmd_flags
|= REQ_DONTPREP
;
1248 EXPORT_SYMBOL(scsi_prep_return
);
1250 int scsi_prep_fn(struct request_queue
*q
, struct request
*req
)
1252 struct scsi_device
*sdev
= q
->queuedata
;
1253 int ret
= BLKPREP_KILL
;
1255 if (req
->cmd_type
== REQ_TYPE_BLOCK_PC
)
1256 ret
= scsi_setup_blk_pc_cmnd(sdev
, req
);
1257 return scsi_prep_return(q
, req
, ret
);
1259 EXPORT_SYMBOL(scsi_prep_fn
);
1262 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1265 * Called with the queue_lock held.
1267 static inline int scsi_dev_queue_ready(struct request_queue
*q
,
1268 struct scsi_device
*sdev
)
1270 if (sdev
->device_busy
== 0 && sdev
->device_blocked
) {
1272 * unblock after device_blocked iterates to zero
1274 if (--sdev
->device_blocked
== 0) {
1276 sdev_printk(KERN_INFO
, sdev
,
1277 "unblocking device at zero depth\n"));
1279 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1283 if (scsi_device_is_busy(sdev
))
1291 * scsi_target_queue_ready: checks if there we can send commands to target
1292 * @sdev: scsi device on starget to check.
1294 * Called with the host lock held.
1296 static inline int scsi_target_queue_ready(struct Scsi_Host
*shost
,
1297 struct scsi_device
*sdev
)
1299 struct scsi_target
*starget
= scsi_target(sdev
);
1301 if (starget
->single_lun
) {
1302 if (starget
->starget_sdev_user
&&
1303 starget
->starget_sdev_user
!= sdev
)
1305 starget
->starget_sdev_user
= sdev
;
1308 if (starget
->target_busy
== 0 && starget
->target_blocked
) {
1310 * unblock after target_blocked iterates to zero
1312 if (--starget
->target_blocked
== 0) {
1313 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO
, starget
,
1314 "unblocking target at zero depth\n"));
1319 if (scsi_target_is_busy(starget
)) {
1320 list_move_tail(&sdev
->starved_entry
, &shost
->starved_list
);
1328 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1329 * return 0. We must end up running the queue again whenever 0 is
1330 * returned, else IO can hang.
1332 * Called with host_lock held.
1334 static inline int scsi_host_queue_ready(struct request_queue
*q
,
1335 struct Scsi_Host
*shost
,
1336 struct scsi_device
*sdev
)
1338 if (scsi_host_in_recovery(shost
))
1340 if (shost
->host_busy
== 0 && shost
->host_blocked
) {
1342 * unblock after host_blocked iterates to zero
1344 if (--shost
->host_blocked
== 0) {
1346 printk("scsi%d unblocking host at zero depth\n",
1352 if (scsi_host_is_busy(shost
)) {
1353 if (list_empty(&sdev
->starved_entry
))
1354 list_add_tail(&sdev
->starved_entry
, &shost
->starved_list
);
1358 /* We're OK to process the command, so we can't be starved */
1359 if (!list_empty(&sdev
->starved_entry
))
1360 list_del_init(&sdev
->starved_entry
);
1366 * Busy state exporting function for request stacking drivers.
1368 * For efficiency, no lock is taken to check the busy state of
1369 * shost/starget/sdev, since the returned value is not guaranteed and
1370 * may be changed after request stacking drivers call the function,
1371 * regardless of taking lock or not.
1373 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1374 * needs to return 'not busy'. Otherwise, request stacking drivers
1375 * may hold requests forever.
1377 static int scsi_lld_busy(struct request_queue
*q
)
1379 struct scsi_device
*sdev
= q
->queuedata
;
1380 struct Scsi_Host
*shost
;
1382 if (blk_queue_dying(q
))
1388 * Ignore host/starget busy state.
1389 * Since block layer does not have a concept of fairness across
1390 * multiple queues, congestion of host/starget needs to be handled
1393 if (scsi_host_in_recovery(shost
) || scsi_device_is_busy(sdev
))
1400 * Kill a request for a dead device
1402 static void scsi_kill_request(struct request
*req
, struct request_queue
*q
)
1404 struct scsi_cmnd
*cmd
= req
->special
;
1405 struct scsi_device
*sdev
;
1406 struct scsi_target
*starget
;
1407 struct Scsi_Host
*shost
;
1409 blk_start_request(req
);
1411 scmd_printk(KERN_INFO
, cmd
, "killing request\n");
1414 starget
= scsi_target(sdev
);
1416 scsi_init_cmd_errh(cmd
);
1417 cmd
->result
= DID_NO_CONNECT
<< 16;
1418 atomic_inc(&cmd
->device
->iorequest_cnt
);
1421 * SCSI request completion path will do scsi_device_unbusy(),
1422 * bump busy counts. To bump the counters, we need to dance
1423 * with the locks as normal issue path does.
1425 sdev
->device_busy
++;
1426 spin_unlock(sdev
->request_queue
->queue_lock
);
1427 spin_lock(shost
->host_lock
);
1429 starget
->target_busy
++;
1430 spin_unlock(shost
->host_lock
);
1431 spin_lock(sdev
->request_queue
->queue_lock
);
1433 blk_complete_request(req
);
1436 static void scsi_softirq_done(struct request
*rq
)
1438 struct scsi_cmnd
*cmd
= rq
->special
;
1439 unsigned long wait_for
= (cmd
->allowed
+ 1) * rq
->timeout
;
1442 INIT_LIST_HEAD(&cmd
->eh_entry
);
1444 atomic_inc(&cmd
->device
->iodone_cnt
);
1446 atomic_inc(&cmd
->device
->ioerr_cnt
);
1448 disposition
= scsi_decide_disposition(cmd
);
1449 if (disposition
!= SUCCESS
&&
1450 time_before(cmd
->jiffies_at_alloc
+ wait_for
, jiffies
)) {
1451 sdev_printk(KERN_ERR
, cmd
->device
,
1452 "timing out command, waited %lus\n",
1454 disposition
= SUCCESS
;
1457 scsi_log_completion(cmd
, disposition
);
1459 switch (disposition
) {
1461 scsi_finish_command(cmd
);
1464 scsi_queue_insert(cmd
, SCSI_MLQUEUE_EH_RETRY
);
1466 case ADD_TO_MLQUEUE
:
1467 scsi_queue_insert(cmd
, SCSI_MLQUEUE_DEVICE_BUSY
);
1470 if (!scsi_eh_scmd_add(cmd
, 0))
1471 scsi_finish_command(cmd
);
1476 * Function: scsi_request_fn()
1478 * Purpose: Main strategy routine for SCSI.
1480 * Arguments: q - Pointer to actual queue.
1484 * Lock status: IO request lock assumed to be held when called.
1486 static void scsi_request_fn(struct request_queue
*q
)
1488 struct scsi_device
*sdev
= q
->queuedata
;
1489 struct Scsi_Host
*shost
;
1490 struct scsi_cmnd
*cmd
;
1491 struct request
*req
;
1493 if(!get_device(&sdev
->sdev_gendev
))
1494 /* We must be tearing the block queue down already */
1498 * To start with, we keep looping until the queue is empty, or until
1499 * the host is no longer able to accept any more requests.
1505 * get next queueable request. We do this early to make sure
1506 * that the request is fully prepared even if we cannot
1509 req
= blk_peek_request(q
);
1510 if (!req
|| !scsi_dev_queue_ready(q
, sdev
))
1513 if (unlikely(!scsi_device_online(sdev
))) {
1514 sdev_printk(KERN_ERR
, sdev
,
1515 "rejecting I/O to offline device\n");
1516 scsi_kill_request(req
, q
);
1522 * Remove the request from the request list.
1524 if (!(blk_queue_tagged(q
) && !blk_queue_start_tag(q
, req
)))
1525 blk_start_request(req
);
1526 sdev
->device_busy
++;
1528 spin_unlock(q
->queue_lock
);
1530 if (unlikely(cmd
== NULL
)) {
1531 printk(KERN_CRIT
"impossible request in %s.\n"
1532 "please mail a stack trace to "
1533 "linux-scsi@vger.kernel.org\n",
1535 blk_dump_rq_flags(req
, "foo");
1538 spin_lock(shost
->host_lock
);
1541 * We hit this when the driver is using a host wide
1542 * tag map. For device level tag maps the queue_depth check
1543 * in the device ready fn would prevent us from trying
1544 * to allocate a tag. Since the map is a shared host resource
1545 * we add the dev to the starved list so it eventually gets
1546 * a run when a tag is freed.
1548 if (blk_queue_tagged(q
) && !blk_rq_tagged(req
)) {
1549 if (list_empty(&sdev
->starved_entry
))
1550 list_add_tail(&sdev
->starved_entry
,
1551 &shost
->starved_list
);
1555 if (!scsi_target_queue_ready(shost
, sdev
))
1558 if (!scsi_host_queue_ready(q
, shost
, sdev
))
1561 scsi_target(sdev
)->target_busy
++;
1565 * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will
1566 * take the lock again.
1568 spin_unlock_irq(shost
->host_lock
);
1571 * Finally, initialize any error handling parameters, and set up
1572 * the timers for timeouts.
1574 scsi_init_cmd_errh(cmd
);
1577 * Dispatch the command to the low-level driver.
1579 rtn
= scsi_dispatch_cmd(cmd
);
1580 spin_lock_irq(q
->queue_lock
);
1588 spin_unlock_irq(shost
->host_lock
);
1591 * lock q, handle tag, requeue req, and decrement device_busy. We
1592 * must return with queue_lock held.
1594 * Decrementing device_busy without checking it is OK, as all such
1595 * cases (host limits or settings) should run the queue at some
1598 spin_lock_irq(q
->queue_lock
);
1599 blk_requeue_request(q
, req
);
1600 sdev
->device_busy
--;
1602 if (sdev
->device_busy
== 0)
1603 blk_delay_queue(q
, SCSI_QUEUE_DELAY
);
1605 /* must be careful here...if we trigger the ->remove() function
1606 * we cannot be holding the q lock */
1607 spin_unlock_irq(q
->queue_lock
);
1608 put_device(&sdev
->sdev_gendev
);
1609 spin_lock_irq(q
->queue_lock
);
1612 u64
scsi_calculate_bounce_limit(struct Scsi_Host
*shost
)
1614 struct device
*host_dev
;
1615 u64 bounce_limit
= 0xffffffff;
1617 if (shost
->unchecked_isa_dma
)
1618 return BLK_BOUNCE_ISA
;
1620 * Platforms with virtual-DMA translation
1621 * hardware have no practical limit.
1623 if (!PCI_DMA_BUS_IS_PHYS
)
1624 return BLK_BOUNCE_ANY
;
1626 host_dev
= scsi_get_device(shost
);
1627 if (host_dev
&& host_dev
->dma_mask
)
1628 bounce_limit
= *host_dev
->dma_mask
;
1630 return bounce_limit
;
1632 EXPORT_SYMBOL(scsi_calculate_bounce_limit
);
1634 struct request_queue
*__scsi_alloc_queue(struct Scsi_Host
*shost
,
1635 request_fn_proc
*request_fn
)
1637 struct request_queue
*q
;
1638 struct device
*dev
= shost
->dma_dev
;
1640 q
= blk_init_queue(request_fn
, NULL
);
1645 * this limit is imposed by hardware restrictions
1647 blk_queue_max_segments(q
, min_t(unsigned short, shost
->sg_tablesize
,
1648 SCSI_MAX_SG_CHAIN_SEGMENTS
));
1650 if (scsi_host_prot_dma(shost
)) {
1651 shost
->sg_prot_tablesize
=
1652 min_not_zero(shost
->sg_prot_tablesize
,
1653 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS
);
1654 BUG_ON(shost
->sg_prot_tablesize
< shost
->sg_tablesize
);
1655 blk_queue_max_integrity_segments(q
, shost
->sg_prot_tablesize
);
1658 blk_queue_max_hw_sectors(q
, shost
->max_sectors
);
1659 blk_queue_bounce_limit(q
, scsi_calculate_bounce_limit(shost
));
1660 blk_queue_segment_boundary(q
, shost
->dma_boundary
);
1661 dma_set_seg_boundary(dev
, shost
->dma_boundary
);
1663 blk_queue_max_segment_size(q
, dma_get_max_seg_size(dev
));
1665 if (!shost
->use_clustering
)
1666 q
->limits
.cluster
= 0;
1669 * set a reasonable default alignment on word boundaries: the
1670 * host and device may alter it using
1671 * blk_queue_update_dma_alignment() later.
1673 blk_queue_dma_alignment(q
, 0x03);
1677 EXPORT_SYMBOL(__scsi_alloc_queue
);
1679 struct request_queue
*scsi_alloc_queue(struct scsi_device
*sdev
)
1681 struct request_queue
*q
;
1683 q
= __scsi_alloc_queue(sdev
->host
, scsi_request_fn
);
1687 blk_queue_prep_rq(q
, scsi_prep_fn
);
1688 blk_queue_softirq_done(q
, scsi_softirq_done
);
1689 blk_queue_rq_timed_out(q
, scsi_times_out
);
1690 blk_queue_lld_busy(q
, scsi_lld_busy
);
1695 * Function: scsi_block_requests()
1697 * Purpose: Utility function used by low-level drivers to prevent further
1698 * commands from being queued to the device.
1700 * Arguments: shost - Host in question
1704 * Lock status: No locks are assumed held.
1706 * Notes: There is no timer nor any other means by which the requests
1707 * get unblocked other than the low-level driver calling
1708 * scsi_unblock_requests().
1710 void scsi_block_requests(struct Scsi_Host
*shost
)
1712 shost
->host_self_blocked
= 1;
1714 EXPORT_SYMBOL(scsi_block_requests
);
1717 * Function: scsi_unblock_requests()
1719 * Purpose: Utility function used by low-level drivers to allow further
1720 * commands from being queued to the device.
1722 * Arguments: shost - Host in question
1726 * Lock status: No locks are assumed held.
1728 * Notes: There is no timer nor any other means by which the requests
1729 * get unblocked other than the low-level driver calling
1730 * scsi_unblock_requests().
1732 * This is done as an API function so that changes to the
1733 * internals of the scsi mid-layer won't require wholesale
1734 * changes to drivers that use this feature.
1736 void scsi_unblock_requests(struct Scsi_Host
*shost
)
1738 shost
->host_self_blocked
= 0;
1739 scsi_run_host_queues(shost
);
1741 EXPORT_SYMBOL(scsi_unblock_requests
);
1743 int __init
scsi_init_queue(void)
1747 scsi_sdb_cache
= kmem_cache_create("scsi_data_buffer",
1748 sizeof(struct scsi_data_buffer
),
1750 if (!scsi_sdb_cache
) {
1751 printk(KERN_ERR
"SCSI: can't init scsi sdb cache\n");
1755 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
1756 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
1757 int size
= sgp
->size
* sizeof(struct scatterlist
);
1759 sgp
->slab
= kmem_cache_create(sgp
->name
, size
, 0,
1760 SLAB_HWCACHE_ALIGN
, NULL
);
1762 printk(KERN_ERR
"SCSI: can't init sg slab %s\n",
1767 sgp
->pool
= mempool_create_slab_pool(SG_MEMPOOL_SIZE
,
1770 printk(KERN_ERR
"SCSI: can't init sg mempool %s\n",
1779 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
1780 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
1782 mempool_destroy(sgp
->pool
);
1784 kmem_cache_destroy(sgp
->slab
);
1786 kmem_cache_destroy(scsi_sdb_cache
);
1791 void scsi_exit_queue(void)
1795 kmem_cache_destroy(scsi_sdb_cache
);
1797 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
1798 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
1799 mempool_destroy(sgp
->pool
);
1800 kmem_cache_destroy(sgp
->slab
);
1805 * scsi_mode_select - issue a mode select
1806 * @sdev: SCSI device to be queried
1807 * @pf: Page format bit (1 == standard, 0 == vendor specific)
1808 * @sp: Save page bit (0 == don't save, 1 == save)
1809 * @modepage: mode page being requested
1810 * @buffer: request buffer (may not be smaller than eight bytes)
1811 * @len: length of request buffer.
1812 * @timeout: command timeout
1813 * @retries: number of retries before failing
1814 * @data: returns a structure abstracting the mode header data
1815 * @sshdr: place to put sense data (or NULL if no sense to be collected).
1816 * must be SCSI_SENSE_BUFFERSIZE big.
1818 * Returns zero if successful; negative error number or scsi
1823 scsi_mode_select(struct scsi_device
*sdev
, int pf
, int sp
, int modepage
,
1824 unsigned char *buffer
, int len
, int timeout
, int retries
,
1825 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
1827 unsigned char cmd
[10];
1828 unsigned char *real_buffer
;
1831 memset(cmd
, 0, sizeof(cmd
));
1832 cmd
[1] = (pf
? 0x10 : 0) | (sp
? 0x01 : 0);
1834 if (sdev
->use_10_for_ms
) {
1837 real_buffer
= kmalloc(8 + len
, GFP_KERNEL
);
1840 memcpy(real_buffer
+ 8, buffer
, len
);
1844 real_buffer
[2] = data
->medium_type
;
1845 real_buffer
[3] = data
->device_specific
;
1846 real_buffer
[4] = data
->longlba
? 0x01 : 0;
1848 real_buffer
[6] = data
->block_descriptor_length
>> 8;
1849 real_buffer
[7] = data
->block_descriptor_length
;
1851 cmd
[0] = MODE_SELECT_10
;
1855 if (len
> 255 || data
->block_descriptor_length
> 255 ||
1859 real_buffer
= kmalloc(4 + len
, GFP_KERNEL
);
1862 memcpy(real_buffer
+ 4, buffer
, len
);
1865 real_buffer
[1] = data
->medium_type
;
1866 real_buffer
[2] = data
->device_specific
;
1867 real_buffer
[3] = data
->block_descriptor_length
;
1870 cmd
[0] = MODE_SELECT
;
1874 ret
= scsi_execute_req(sdev
, cmd
, DMA_TO_DEVICE
, real_buffer
, len
,
1875 sshdr
, timeout
, retries
, NULL
);
1879 EXPORT_SYMBOL_GPL(scsi_mode_select
);
1882 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
1883 * @sdev: SCSI device to be queried
1884 * @dbd: set if mode sense will allow block descriptors to be returned
1885 * @modepage: mode page being requested
1886 * @buffer: request buffer (may not be smaller than eight bytes)
1887 * @len: length of request buffer.
1888 * @timeout: command timeout
1889 * @retries: number of retries before failing
1890 * @data: returns a structure abstracting the mode header data
1891 * @sshdr: place to put sense data (or NULL if no sense to be collected).
1892 * must be SCSI_SENSE_BUFFERSIZE big.
1894 * Returns zero if unsuccessful, or the header offset (either 4
1895 * or 8 depending on whether a six or ten byte command was
1896 * issued) if successful.
1899 scsi_mode_sense(struct scsi_device
*sdev
, int dbd
, int modepage
,
1900 unsigned char *buffer
, int len
, int timeout
, int retries
,
1901 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
)
1903 unsigned char cmd
[12];
1907 struct scsi_sense_hdr my_sshdr
;
1909 memset(data
, 0, sizeof(*data
));
1910 memset(&cmd
[0], 0, 12);
1911 cmd
[1] = dbd
& 0x18; /* allows DBD and LLBA bits */
1914 /* caller might not be interested in sense, but we need it */
1919 use_10_for_ms
= sdev
->use_10_for_ms
;
1921 if (use_10_for_ms
) {
1925 cmd
[0] = MODE_SENSE_10
;
1932 cmd
[0] = MODE_SENSE
;
1937 memset(buffer
, 0, len
);
1939 result
= scsi_execute_req(sdev
, cmd
, DMA_FROM_DEVICE
, buffer
, len
,
1940 sshdr
, timeout
, retries
, NULL
);
1942 /* This code looks awful: what it's doing is making sure an
1943 * ILLEGAL REQUEST sense return identifies the actual command
1944 * byte as the problem. MODE_SENSE commands can return
1945 * ILLEGAL REQUEST if the code page isn't supported */
1947 if (use_10_for_ms
&& !scsi_status_is_good(result
) &&
1948 (driver_byte(result
) & DRIVER_SENSE
)) {
1949 if (scsi_sense_valid(sshdr
)) {
1950 if ((sshdr
->sense_key
== ILLEGAL_REQUEST
) &&
1951 (sshdr
->asc
== 0x20) && (sshdr
->ascq
== 0)) {
1953 * Invalid command operation code
1955 sdev
->use_10_for_ms
= 0;
1961 if(scsi_status_is_good(result
)) {
1962 if (unlikely(buffer
[0] == 0x86 && buffer
[1] == 0x0b &&
1963 (modepage
== 6 || modepage
== 8))) {
1964 /* Initio breakage? */
1967 data
->medium_type
= 0;
1968 data
->device_specific
= 0;
1970 data
->block_descriptor_length
= 0;
1971 } else if(use_10_for_ms
) {
1972 data
->length
= buffer
[0]*256 + buffer
[1] + 2;
1973 data
->medium_type
= buffer
[2];
1974 data
->device_specific
= buffer
[3];
1975 data
->longlba
= buffer
[4] & 0x01;
1976 data
->block_descriptor_length
= buffer
[6]*256
1979 data
->length
= buffer
[0] + 1;
1980 data
->medium_type
= buffer
[1];
1981 data
->device_specific
= buffer
[2];
1982 data
->block_descriptor_length
= buffer
[3];
1984 data
->header_length
= header_length
;
1989 EXPORT_SYMBOL(scsi_mode_sense
);
1992 * scsi_test_unit_ready - test if unit is ready
1993 * @sdev: scsi device to change the state of.
1994 * @timeout: command timeout
1995 * @retries: number of retries before failing
1996 * @sshdr_external: Optional pointer to struct scsi_sense_hdr for
1997 * returning sense. Make sure that this is cleared before passing
2000 * Returns zero if unsuccessful or an error if TUR failed. For
2001 * removable media, UNIT_ATTENTION sets ->changed flag.
2004 scsi_test_unit_ready(struct scsi_device
*sdev
, int timeout
, int retries
,
2005 struct scsi_sense_hdr
*sshdr_external
)
2008 TEST_UNIT_READY
, 0, 0, 0, 0, 0,
2010 struct scsi_sense_hdr
*sshdr
;
2013 if (!sshdr_external
)
2014 sshdr
= kzalloc(sizeof(*sshdr
), GFP_KERNEL
);
2016 sshdr
= sshdr_external
;
2018 /* try to eat the UNIT_ATTENTION if there are enough retries */
2020 result
= scsi_execute_req(sdev
, cmd
, DMA_NONE
, NULL
, 0, sshdr
,
2021 timeout
, retries
, NULL
);
2022 if (sdev
->removable
&& scsi_sense_valid(sshdr
) &&
2023 sshdr
->sense_key
== UNIT_ATTENTION
)
2025 } while (scsi_sense_valid(sshdr
) &&
2026 sshdr
->sense_key
== UNIT_ATTENTION
&& --retries
);
2028 if (!sshdr_external
)
2032 EXPORT_SYMBOL(scsi_test_unit_ready
);
2035 * scsi_device_set_state - Take the given device through the device state model.
2036 * @sdev: scsi device to change the state of.
2037 * @state: state to change to.
2039 * Returns zero if unsuccessful or an error if the requested
2040 * transition is illegal.
2043 scsi_device_set_state(struct scsi_device
*sdev
, enum scsi_device_state state
)
2045 enum scsi_device_state oldstate
= sdev
->sdev_state
;
2047 if (state
== oldstate
)
2053 case SDEV_CREATED_BLOCK
:
2064 case SDEV_TRANSPORT_OFFLINE
:
2077 case SDEV_TRANSPORT_OFFLINE
:
2085 case SDEV_TRANSPORT_OFFLINE
:
2100 case SDEV_CREATED_BLOCK
:
2107 case SDEV_CREATED_BLOCK
:
2122 case SDEV_TRANSPORT_OFFLINE
:
2135 case SDEV_TRANSPORT_OFFLINE
:
2144 sdev
->sdev_state
= state
;
2148 SCSI_LOG_ERROR_RECOVERY(1,
2149 sdev_printk(KERN_ERR
, sdev
,
2150 "Illegal state transition %s->%s\n",
2151 scsi_device_state_name(oldstate
),
2152 scsi_device_state_name(state
))
2156 EXPORT_SYMBOL(scsi_device_set_state
);
2159 * sdev_evt_emit - emit a single SCSI device uevent
2160 * @sdev: associated SCSI device
2161 * @evt: event to emit
2163 * Send a single uevent (scsi_event) to the associated scsi_device.
2165 static void scsi_evt_emit(struct scsi_device
*sdev
, struct scsi_event
*evt
)
2170 switch (evt
->evt_type
) {
2171 case SDEV_EVT_MEDIA_CHANGE
:
2172 envp
[idx
++] = "SDEV_MEDIA_CHANGE=1";
2182 kobject_uevent_env(&sdev
->sdev_gendev
.kobj
, KOBJ_CHANGE
, envp
);
2186 * sdev_evt_thread - send a uevent for each scsi event
2187 * @work: work struct for scsi_device
2189 * Dispatch queued events to their associated scsi_device kobjects
2192 void scsi_evt_thread(struct work_struct
*work
)
2194 struct scsi_device
*sdev
;
2195 LIST_HEAD(event_list
);
2197 sdev
= container_of(work
, struct scsi_device
, event_work
);
2200 struct scsi_event
*evt
;
2201 struct list_head
*this, *tmp
;
2202 unsigned long flags
;
2204 spin_lock_irqsave(&sdev
->list_lock
, flags
);
2205 list_splice_init(&sdev
->event_list
, &event_list
);
2206 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
2208 if (list_empty(&event_list
))
2211 list_for_each_safe(this, tmp
, &event_list
) {
2212 evt
= list_entry(this, struct scsi_event
, node
);
2213 list_del(&evt
->node
);
2214 scsi_evt_emit(sdev
, evt
);
2221 * sdev_evt_send - send asserted event to uevent thread
2222 * @sdev: scsi_device event occurred on
2223 * @evt: event to send
2225 * Assert scsi device event asynchronously.
2227 void sdev_evt_send(struct scsi_device
*sdev
, struct scsi_event
*evt
)
2229 unsigned long flags
;
2232 /* FIXME: currently this check eliminates all media change events
2233 * for polled devices. Need to update to discriminate between AN
2234 * and polled events */
2235 if (!test_bit(evt
->evt_type
, sdev
->supported_events
)) {
2241 spin_lock_irqsave(&sdev
->list_lock
, flags
);
2242 list_add_tail(&evt
->node
, &sdev
->event_list
);
2243 schedule_work(&sdev
->event_work
);
2244 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
2246 EXPORT_SYMBOL_GPL(sdev_evt_send
);
2249 * sdev_evt_alloc - allocate a new scsi event
2250 * @evt_type: type of event to allocate
2251 * @gfpflags: GFP flags for allocation
2253 * Allocates and returns a new scsi_event.
2255 struct scsi_event
*sdev_evt_alloc(enum scsi_device_event evt_type
,
2258 struct scsi_event
*evt
= kzalloc(sizeof(struct scsi_event
), gfpflags
);
2262 evt
->evt_type
= evt_type
;
2263 INIT_LIST_HEAD(&evt
->node
);
2265 /* evt_type-specific initialization, if any */
2267 case SDEV_EVT_MEDIA_CHANGE
:
2275 EXPORT_SYMBOL_GPL(sdev_evt_alloc
);
2278 * sdev_evt_send_simple - send asserted event to uevent thread
2279 * @sdev: scsi_device event occurred on
2280 * @evt_type: type of event to send
2281 * @gfpflags: GFP flags for allocation
2283 * Assert scsi device event asynchronously, given an event type.
2285 void sdev_evt_send_simple(struct scsi_device
*sdev
,
2286 enum scsi_device_event evt_type
, gfp_t gfpflags
)
2288 struct scsi_event
*evt
= sdev_evt_alloc(evt_type
, gfpflags
);
2290 sdev_printk(KERN_ERR
, sdev
, "event %d eaten due to OOM\n",
2295 sdev_evt_send(sdev
, evt
);
2297 EXPORT_SYMBOL_GPL(sdev_evt_send_simple
);
2300 * scsi_device_quiesce - Block user issued commands.
2301 * @sdev: scsi device to quiesce.
2303 * This works by trying to transition to the SDEV_QUIESCE state
2304 * (which must be a legal transition). When the device is in this
2305 * state, only special requests will be accepted, all others will
2306 * be deferred. Since special requests may also be requeued requests,
2307 * a successful return doesn't guarantee the device will be
2308 * totally quiescent.
2310 * Must be called with user context, may sleep.
2312 * Returns zero if unsuccessful or an error if not.
2315 scsi_device_quiesce(struct scsi_device
*sdev
)
2317 int err
= scsi_device_set_state(sdev
, SDEV_QUIESCE
);
2321 scsi_run_queue(sdev
->request_queue
);
2322 while (sdev
->device_busy
) {
2323 msleep_interruptible(200);
2324 scsi_run_queue(sdev
->request_queue
);
2328 EXPORT_SYMBOL(scsi_device_quiesce
);
2331 * scsi_device_resume - Restart user issued commands to a quiesced device.
2332 * @sdev: scsi device to resume.
2334 * Moves the device from quiesced back to running and restarts the
2337 * Must be called with user context, may sleep.
2339 void scsi_device_resume(struct scsi_device
*sdev
)
2341 /* check if the device state was mutated prior to resume, and if
2342 * so assume the state is being managed elsewhere (for example
2343 * device deleted during suspend)
2345 if (sdev
->sdev_state
!= SDEV_QUIESCE
||
2346 scsi_device_set_state(sdev
, SDEV_RUNNING
))
2348 scsi_run_queue(sdev
->request_queue
);
2350 EXPORT_SYMBOL(scsi_device_resume
);
2353 device_quiesce_fn(struct scsi_device
*sdev
, void *data
)
2355 scsi_device_quiesce(sdev
);
2359 scsi_target_quiesce(struct scsi_target
*starget
)
2361 starget_for_each_device(starget
, NULL
, device_quiesce_fn
);
2363 EXPORT_SYMBOL(scsi_target_quiesce
);
2366 device_resume_fn(struct scsi_device
*sdev
, void *data
)
2368 scsi_device_resume(sdev
);
2372 scsi_target_resume(struct scsi_target
*starget
)
2374 starget_for_each_device(starget
, NULL
, device_resume_fn
);
2376 EXPORT_SYMBOL(scsi_target_resume
);
2379 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state
2380 * @sdev: device to block
2382 * Block request made by scsi lld's to temporarily stop all
2383 * scsi commands on the specified device. Called from interrupt
2384 * or normal process context.
2386 * Returns zero if successful or error if not
2389 * This routine transitions the device to the SDEV_BLOCK state
2390 * (which must be a legal transition). When the device is in this
2391 * state, all commands are deferred until the scsi lld reenables
2392 * the device with scsi_device_unblock or device_block_tmo fires.
2395 scsi_internal_device_block(struct scsi_device
*sdev
)
2397 struct request_queue
*q
= sdev
->request_queue
;
2398 unsigned long flags
;
2401 err
= scsi_device_set_state(sdev
, SDEV_BLOCK
);
2403 err
= scsi_device_set_state(sdev
, SDEV_CREATED_BLOCK
);
2410 * The device has transitioned to SDEV_BLOCK. Stop the
2411 * block layer from calling the midlayer with this device's
2414 spin_lock_irqsave(q
->queue_lock
, flags
);
2416 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2420 EXPORT_SYMBOL_GPL(scsi_internal_device_block
);
2423 * scsi_internal_device_unblock - resume a device after a block request
2424 * @sdev: device to resume
2425 * @new_state: state to set devices to after unblocking
2427 * Called by scsi lld's or the midlayer to restart the device queue
2428 * for the previously suspended scsi device. Called from interrupt or
2429 * normal process context.
2431 * Returns zero if successful or error if not.
2434 * This routine transitions the device to the SDEV_RUNNING state
2435 * or to one of the offline states (which must be a legal transition)
2436 * allowing the midlayer to goose the queue for this device.
2439 scsi_internal_device_unblock(struct scsi_device
*sdev
,
2440 enum scsi_device_state new_state
)
2442 struct request_queue
*q
= sdev
->request_queue
;
2443 unsigned long flags
;
2446 * Try to transition the scsi device to SDEV_RUNNING or one of the
2447 * offlined states and goose the device queue if successful.
2449 if ((sdev
->sdev_state
== SDEV_BLOCK
) ||
2450 (sdev
->sdev_state
== SDEV_TRANSPORT_OFFLINE
))
2451 sdev
->sdev_state
= new_state
;
2452 else if (sdev
->sdev_state
== SDEV_CREATED_BLOCK
) {
2453 if (new_state
== SDEV_TRANSPORT_OFFLINE
||
2454 new_state
== SDEV_OFFLINE
)
2455 sdev
->sdev_state
= new_state
;
2457 sdev
->sdev_state
= SDEV_CREATED
;
2458 } else if (sdev
->sdev_state
!= SDEV_CANCEL
&&
2459 sdev
->sdev_state
!= SDEV_OFFLINE
)
2462 spin_lock_irqsave(q
->queue_lock
, flags
);
2464 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2468 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock
);
2471 device_block(struct scsi_device
*sdev
, void *data
)
2473 scsi_internal_device_block(sdev
);
2477 target_block(struct device
*dev
, void *data
)
2479 if (scsi_is_target_device(dev
))
2480 starget_for_each_device(to_scsi_target(dev
), NULL
,
2486 scsi_target_block(struct device
*dev
)
2488 if (scsi_is_target_device(dev
))
2489 starget_for_each_device(to_scsi_target(dev
), NULL
,
2492 device_for_each_child(dev
, NULL
, target_block
);
2494 EXPORT_SYMBOL_GPL(scsi_target_block
);
2497 device_unblock(struct scsi_device
*sdev
, void *data
)
2499 scsi_internal_device_unblock(sdev
, *(enum scsi_device_state
*)data
);
2503 target_unblock(struct device
*dev
, void *data
)
2505 if (scsi_is_target_device(dev
))
2506 starget_for_each_device(to_scsi_target(dev
), data
,
2512 scsi_target_unblock(struct device
*dev
, enum scsi_device_state new_state
)
2514 if (scsi_is_target_device(dev
))
2515 starget_for_each_device(to_scsi_target(dev
), &new_state
,
2518 device_for_each_child(dev
, &new_state
, target_unblock
);
2520 EXPORT_SYMBOL_GPL(scsi_target_unblock
);
2523 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
2524 * @sgl: scatter-gather list
2525 * @sg_count: number of segments in sg
2526 * @offset: offset in bytes into sg, on return offset into the mapped area
2527 * @len: bytes to map, on return number of bytes mapped
2529 * Returns virtual address of the start of the mapped page
2531 void *scsi_kmap_atomic_sg(struct scatterlist
*sgl
, int sg_count
,
2532 size_t *offset
, size_t *len
)
2535 size_t sg_len
= 0, len_complete
= 0;
2536 struct scatterlist
*sg
;
2539 WARN_ON(!irqs_disabled());
2541 for_each_sg(sgl
, sg
, sg_count
, i
) {
2542 len_complete
= sg_len
; /* Complete sg-entries */
2543 sg_len
+= sg
->length
;
2544 if (sg_len
> *offset
)
2548 if (unlikely(i
== sg_count
)) {
2549 printk(KERN_ERR
"%s: Bytes in sg: %zu, requested offset %zu, "
2551 __func__
, sg_len
, *offset
, sg_count
);
2556 /* Offset starting from the beginning of first page in this sg-entry */
2557 *offset
= *offset
- len_complete
+ sg
->offset
;
2559 /* Assumption: contiguous pages can be accessed as "page + i" */
2560 page
= nth_page(sg_page(sg
), (*offset
>> PAGE_SHIFT
));
2561 *offset
&= ~PAGE_MASK
;
2563 /* Bytes in this sg-entry from *offset to the end of the page */
2564 sg_len
= PAGE_SIZE
- *offset
;
2568 return kmap_atomic(page
);
2570 EXPORT_SYMBOL(scsi_kmap_atomic_sg
);
2573 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
2574 * @virt: virtual address to be unmapped
2576 void scsi_kunmap_atomic_sg(void *virt
)
2578 kunmap_atomic(virt
);
2580 EXPORT_SYMBOL(scsi_kunmap_atomic_sg
);
2582 void sdev_disable_disk_events(struct scsi_device
*sdev
)
2584 atomic_inc(&sdev
->disk_events_disable_depth
);
2586 EXPORT_SYMBOL(sdev_disable_disk_events
);
2588 void sdev_enable_disk_events(struct scsi_device
*sdev
)
2590 if (WARN_ON_ONCE(atomic_read(&sdev
->disk_events_disable_depth
) <= 0))
2592 atomic_dec(&sdev
->disk_events_disable_depth
);
2594 EXPORT_SYMBOL(sdev_enable_disk_events
);