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/blkdev.h>
12 #include <linux/completion.h>
13 #include <linux/kernel.h>
14 #include <linux/mempool.h>
15 #include <linux/slab.h>
16 #include <linux/init.h>
17 #include <linux/pci.h>
18 #include <linux/delay.h>
20 #include <scsi/scsi.h>
21 #include <scsi/scsi_dbg.h>
22 #include <scsi/scsi_device.h>
23 #include <scsi/scsi_driver.h>
24 #include <scsi/scsi_eh.h>
25 #include <scsi/scsi_host.h>
26 #include <scsi/scsi_request.h>
28 #include "scsi_priv.h"
29 #include "scsi_logging.h"
32 #define SG_MEMPOOL_NR (sizeof(scsi_sg_pools)/sizeof(struct scsi_host_sg_pool))
33 #define SG_MEMPOOL_SIZE 32
35 struct scsi_host_sg_pool
{
42 #if (SCSI_MAX_PHYS_SEGMENTS < 32)
43 #error SCSI_MAX_PHYS_SEGMENTS is too small
46 #define SP(x) { x, "sgpool-" #x }
47 static struct scsi_host_sg_pool scsi_sg_pools
[] = {
51 #if (SCSI_MAX_PHYS_SEGMENTS > 32)
53 #if (SCSI_MAX_PHYS_SEGMENTS > 64)
55 #if (SCSI_MAX_PHYS_SEGMENTS > 128)
57 #if (SCSI_MAX_PHYS_SEGMENTS > 256)
58 #error SCSI_MAX_PHYS_SEGMENTS is too large
68 * Function: scsi_insert_special_req()
70 * Purpose: Insert pre-formed request into request queue.
72 * Arguments: sreq - request that is ready to be queued.
73 * at_head - boolean. True if we should insert at head
74 * of queue, false if we should insert at tail.
76 * Lock status: Assumed that lock is not held upon entry.
80 * Notes: This function is called from character device and from
81 * ioctl types of functions where the caller knows exactly
82 * what SCSI command needs to be issued. The idea is that
83 * we merely inject the command into the queue (at the head
84 * for now), and then call the queue request function to actually
87 int scsi_insert_special_req(struct scsi_request
*sreq
, int at_head
)
90 * Because users of this function are apt to reuse requests with no
91 * modification, we have to sanitise the request flags here
93 sreq
->sr_request
->flags
&= ~REQ_DONTPREP
;
94 blk_insert_request(sreq
->sr_device
->request_queue
, sreq
->sr_request
,
99 static void scsi_run_queue(struct request_queue
*q
);
102 * Function: scsi_unprep_request()
104 * Purpose: Remove all preparation done for a request, including its
105 * associated scsi_cmnd, so that it can be requeued.
107 * Arguments: req - request to unprepare
109 * Lock status: Assumed that no locks are held upon entry.
113 static void scsi_unprep_request(struct request
*req
)
115 struct scsi_cmnd
*cmd
= req
->special
;
117 req
->flags
&= ~REQ_DONTPREP
;
118 req
->special
= (req
->flags
& REQ_SPECIAL
) ? cmd
->sc_request
: NULL
;
120 scsi_put_command(cmd
);
124 * Function: scsi_queue_insert()
126 * Purpose: Insert a command in the midlevel queue.
128 * Arguments: cmd - command that we are adding to queue.
129 * reason - why we are inserting command to queue.
131 * Lock status: Assumed that lock is not held upon entry.
135 * Notes: We do this for one of two cases. Either the host is busy
136 * and it cannot accept any more commands for the time being,
137 * or the device returned QUEUE_FULL and can accept no more
139 * Notes: This could be called either from an interrupt context or a
140 * normal process context.
142 int scsi_queue_insert(struct scsi_cmnd
*cmd
, int reason
)
144 struct Scsi_Host
*host
= cmd
->device
->host
;
145 struct scsi_device
*device
= cmd
->device
;
146 struct request_queue
*q
= device
->request_queue
;
150 printk("Inserting command %p into mlqueue\n", cmd
));
153 * Set the appropriate busy bit for the device/host.
155 * If the host/device isn't busy, assume that something actually
156 * completed, and that we should be able to queue a command now.
158 * Note that the prior mid-layer assumption that any host could
159 * always queue at least one command is now broken. The mid-layer
160 * will implement a user specifiable stall (see
161 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
162 * if a command is requeued with no other commands outstanding
163 * either for the device or for the host.
165 if (reason
== SCSI_MLQUEUE_HOST_BUSY
)
166 host
->host_blocked
= host
->max_host_blocked
;
167 else if (reason
== SCSI_MLQUEUE_DEVICE_BUSY
)
168 device
->device_blocked
= device
->max_device_blocked
;
171 * Decrement the counters, since these commands are no longer
172 * active on the host/device.
174 scsi_device_unbusy(device
);
177 * Requeue this command. It will go before all other commands
178 * that are already in the queue.
180 * NOTE: there is magic here about the way the queue is plugged if
181 * we have no outstanding commands.
183 * Although we *don't* plug the queue, we call the request
184 * function. The SCSI request function detects the blocked condition
185 * and plugs the queue appropriately.
187 spin_lock_irqsave(q
->queue_lock
, flags
);
188 blk_requeue_request(q
, cmd
->request
);
189 spin_unlock_irqrestore(q
->queue_lock
, flags
);
197 * Function: scsi_do_req
199 * Purpose: Queue a SCSI request
201 * Arguments: sreq - command descriptor.
202 * cmnd - actual SCSI command to be performed.
203 * buffer - data buffer.
204 * bufflen - size of data buffer.
205 * done - completion function to be run.
206 * timeout - how long to let it run before timeout.
207 * retries - number of retries we allow.
209 * Lock status: No locks held upon entry.
213 * Notes: This function is only used for queueing requests for things
214 * like ioctls and character device requests - this is because
215 * we essentially just inject a request into the queue for the
218 * In order to support the scsi_device_quiesce function, we
219 * now inject requests on the *head* of the device queue
220 * rather than the tail.
222 void scsi_do_req(struct scsi_request
*sreq
, const void *cmnd
,
223 void *buffer
, unsigned bufflen
,
224 void (*done
)(struct scsi_cmnd
*),
225 int timeout
, int retries
)
228 * If the upper level driver is reusing these things, then
229 * we should release the low-level block now. Another one will
230 * be allocated later when this request is getting queued.
232 __scsi_release_request(sreq
);
235 * Our own function scsi_done (which marks the host as not busy,
236 * disables the timeout counter, etc) will be called by us or by the
237 * scsi_hosts[host].queuecommand() function needs to also call
238 * the completion function for the high level driver.
240 memcpy(sreq
->sr_cmnd
, cmnd
, sizeof(sreq
->sr_cmnd
));
241 sreq
->sr_bufflen
= bufflen
;
242 sreq
->sr_buffer
= buffer
;
243 sreq
->sr_allowed
= retries
;
244 sreq
->sr_done
= done
;
245 sreq
->sr_timeout_per_command
= timeout
;
247 if (sreq
->sr_cmd_len
== 0)
248 sreq
->sr_cmd_len
= COMMAND_SIZE(sreq
->sr_cmnd
[0]);
251 * head injection *required* here otherwise quiesce won't work
253 scsi_insert_special_req(sreq
, 1);
255 EXPORT_SYMBOL(scsi_do_req
);
258 * scsi_execute - insert request and wait for the result
261 * @data_direction: data direction
262 * @buffer: data buffer
263 * @bufflen: len of buffer
264 * @sense: optional sense buffer
265 * @timeout: request timeout in seconds
266 * @retries: number of times to retry request
267 * @flags: or into request flags;
269 * returns the req->errors value which is the the scsi_cmnd result
272 int scsi_execute(struct scsi_device
*sdev
, const unsigned char *cmd
,
273 int data_direction
, void *buffer
, unsigned bufflen
,
274 unsigned char *sense
, int timeout
, int retries
, int flags
)
277 int write
= (data_direction
== DMA_TO_DEVICE
);
278 int ret
= DRIVER_ERROR
<< 24;
280 req
= blk_get_request(sdev
->request_queue
, write
, __GFP_WAIT
);
282 if (bufflen
&& blk_rq_map_kern(sdev
->request_queue
, req
,
283 buffer
, bufflen
, __GFP_WAIT
))
286 req
->cmd_len
= COMMAND_SIZE(cmd
[0]);
287 memcpy(req
->cmd
, cmd
, req
->cmd_len
);
290 req
->timeout
= timeout
;
291 req
->flags
|= flags
| REQ_BLOCK_PC
| REQ_SPECIAL
| REQ_QUIET
;
294 * head injection *required* here otherwise quiesce won't work
296 blk_execute_rq(req
->q
, NULL
, req
, 1);
300 blk_put_request(req
);
304 EXPORT_SYMBOL(scsi_execute
);
307 int scsi_execute_req(struct scsi_device
*sdev
, const unsigned char *cmd
,
308 int data_direction
, void *buffer
, unsigned bufflen
,
309 struct scsi_sense_hdr
*sshdr
, int timeout
, int retries
)
315 sense
= kmalloc(SCSI_SENSE_BUFFERSIZE
, GFP_NOIO
);
317 return DRIVER_ERROR
<< 24;
318 memset(sense
, 0, SCSI_SENSE_BUFFERSIZE
);
320 result
= scsi_execute(sdev
, cmd
, data_direction
, buffer
, bufflen
,
321 sense
, timeout
, retries
, 0);
323 scsi_normalize_sense(sense
, SCSI_SENSE_BUFFERSIZE
, sshdr
);
328 EXPORT_SYMBOL(scsi_execute_req
);
331 * Function: scsi_init_cmd_errh()
333 * Purpose: Initialize cmd fields related to error handling.
335 * Arguments: cmd - command that is ready to be queued.
339 * Notes: This function has the job of initializing a number of
340 * fields related to error handling. Typically this will
341 * be called once for each command, as required.
343 static int scsi_init_cmd_errh(struct scsi_cmnd
*cmd
)
345 cmd
->serial_number
= 0;
347 memset(cmd
->sense_buffer
, 0, sizeof cmd
->sense_buffer
);
349 if (cmd
->cmd_len
== 0)
350 cmd
->cmd_len
= COMMAND_SIZE(cmd
->cmnd
[0]);
353 * We need saved copies of a number of fields - this is because
354 * error handling may need to overwrite these with different values
355 * to run different commands, and once error handling is complete,
356 * we will need to restore these values prior to running the actual
359 cmd
->old_use_sg
= cmd
->use_sg
;
360 cmd
->old_cmd_len
= cmd
->cmd_len
;
361 cmd
->sc_old_data_direction
= cmd
->sc_data_direction
;
362 cmd
->old_underflow
= cmd
->underflow
;
363 memcpy(cmd
->data_cmnd
, cmd
->cmnd
, sizeof(cmd
->cmnd
));
364 cmd
->buffer
= cmd
->request_buffer
;
365 cmd
->bufflen
= cmd
->request_bufflen
;
371 * Function: scsi_setup_cmd_retry()
373 * Purpose: Restore the command state for a retry
375 * Arguments: cmd - command to be restored
379 * Notes: Immediately prior to retrying a command, we need
380 * to restore certain fields that we saved above.
382 void scsi_setup_cmd_retry(struct scsi_cmnd
*cmd
)
384 memcpy(cmd
->cmnd
, cmd
->data_cmnd
, sizeof(cmd
->data_cmnd
));
385 cmd
->request_buffer
= cmd
->buffer
;
386 cmd
->request_bufflen
= cmd
->bufflen
;
387 cmd
->use_sg
= cmd
->old_use_sg
;
388 cmd
->cmd_len
= cmd
->old_cmd_len
;
389 cmd
->sc_data_direction
= cmd
->sc_old_data_direction
;
390 cmd
->underflow
= cmd
->old_underflow
;
393 void scsi_device_unbusy(struct scsi_device
*sdev
)
395 struct Scsi_Host
*shost
= sdev
->host
;
398 spin_lock_irqsave(shost
->host_lock
, flags
);
400 if (unlikely(scsi_host_in_recovery(shost
) &&
402 scsi_eh_wakeup(shost
);
403 spin_unlock(shost
->host_lock
);
404 spin_lock(sdev
->request_queue
->queue_lock
);
406 spin_unlock_irqrestore(sdev
->request_queue
->queue_lock
, flags
);
410 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
411 * and call blk_run_queue for all the scsi_devices on the target -
412 * including current_sdev first.
414 * Called with *no* scsi locks held.
416 static void scsi_single_lun_run(struct scsi_device
*current_sdev
)
418 struct Scsi_Host
*shost
= current_sdev
->host
;
419 struct scsi_device
*sdev
, *tmp
;
420 struct scsi_target
*starget
= scsi_target(current_sdev
);
423 spin_lock_irqsave(shost
->host_lock
, flags
);
424 starget
->starget_sdev_user
= NULL
;
425 spin_unlock_irqrestore(shost
->host_lock
, flags
);
428 * Call blk_run_queue for all LUNs on the target, starting with
429 * current_sdev. We race with others (to set starget_sdev_user),
430 * but in most cases, we will be first. Ideally, each LU on the
431 * target would get some limited time or requests on the target.
433 blk_run_queue(current_sdev
->request_queue
);
435 spin_lock_irqsave(shost
->host_lock
, flags
);
436 if (starget
->starget_sdev_user
)
438 list_for_each_entry_safe(sdev
, tmp
, &starget
->devices
,
439 same_target_siblings
) {
440 if (sdev
== current_sdev
)
442 if (scsi_device_get(sdev
))
445 spin_unlock_irqrestore(shost
->host_lock
, flags
);
446 blk_run_queue(sdev
->request_queue
);
447 spin_lock_irqsave(shost
->host_lock
, flags
);
449 scsi_device_put(sdev
);
452 spin_unlock_irqrestore(shost
->host_lock
, flags
);
456 * Function: scsi_run_queue()
458 * Purpose: Select a proper request queue to serve next
460 * Arguments: q - last request's queue
464 * Notes: The previous command was completely finished, start
465 * a new one if possible.
467 static void scsi_run_queue(struct request_queue
*q
)
469 struct scsi_device
*sdev
= q
->queuedata
;
470 struct Scsi_Host
*shost
= sdev
->host
;
473 if (sdev
->single_lun
)
474 scsi_single_lun_run(sdev
);
476 spin_lock_irqsave(shost
->host_lock
, flags
);
477 while (!list_empty(&shost
->starved_list
) &&
478 !shost
->host_blocked
&& !shost
->host_self_blocked
&&
479 !((shost
->can_queue
> 0) &&
480 (shost
->host_busy
>= shost
->can_queue
))) {
482 * As long as shost is accepting commands and we have
483 * starved queues, call blk_run_queue. scsi_request_fn
484 * drops the queue_lock and can add us back to the
487 * host_lock protects the starved_list and starved_entry.
488 * scsi_request_fn must get the host_lock before checking
489 * or modifying starved_list or starved_entry.
491 sdev
= list_entry(shost
->starved_list
.next
,
492 struct scsi_device
, starved_entry
);
493 list_del_init(&sdev
->starved_entry
);
494 spin_unlock_irqrestore(shost
->host_lock
, flags
);
496 blk_run_queue(sdev
->request_queue
);
498 spin_lock_irqsave(shost
->host_lock
, flags
);
499 if (unlikely(!list_empty(&sdev
->starved_entry
)))
501 * sdev lost a race, and was put back on the
502 * starved list. This is unlikely but without this
503 * in theory we could loop forever.
507 spin_unlock_irqrestore(shost
->host_lock
, flags
);
513 * Function: scsi_requeue_command()
515 * Purpose: Handle post-processing of completed commands.
517 * Arguments: q - queue to operate on
518 * cmd - command that may need to be requeued.
522 * Notes: After command completion, there may be blocks left
523 * over which weren't finished by the previous command
524 * this can be for a number of reasons - the main one is
525 * I/O errors in the middle of the request, in which case
526 * we need to request the blocks that come after the bad
528 * Notes: Upon return, cmd is a stale pointer.
530 static void scsi_requeue_command(struct request_queue
*q
, struct scsi_cmnd
*cmd
)
532 struct request
*req
= cmd
->request
;
535 scsi_unprep_request(req
);
536 spin_lock_irqsave(q
->queue_lock
, flags
);
537 blk_requeue_request(q
, req
);
538 spin_unlock_irqrestore(q
->queue_lock
, flags
);
543 void scsi_next_command(struct scsi_cmnd
*cmd
)
545 struct scsi_device
*sdev
= cmd
->device
;
546 struct request_queue
*q
= sdev
->request_queue
;
548 /* need to hold a reference on the device before we let go of the cmd */
549 get_device(&sdev
->sdev_gendev
);
551 scsi_put_command(cmd
);
554 /* ok to remove device now */
555 put_device(&sdev
->sdev_gendev
);
558 void scsi_run_host_queues(struct Scsi_Host
*shost
)
560 struct scsi_device
*sdev
;
562 shost_for_each_device(sdev
, shost
)
563 scsi_run_queue(sdev
->request_queue
);
567 * Function: scsi_end_request()
569 * Purpose: Post-processing of completed commands (usually invoked at end
570 * of upper level post-processing and scsi_io_completion).
572 * Arguments: cmd - command that is complete.
573 * uptodate - 1 if I/O indicates success, <= 0 for I/O error.
574 * bytes - number of bytes of completed I/O
575 * requeue - indicates whether we should requeue leftovers.
577 * Lock status: Assumed that lock is not held upon entry.
579 * Returns: cmd if requeue required, NULL otherwise.
581 * Notes: This is called for block device requests in order to
582 * mark some number of sectors as complete.
584 * We are guaranteeing that the request queue will be goosed
585 * at some point during this call.
586 * Notes: If cmd was requeued, upon return it will be a stale pointer.
588 static struct scsi_cmnd
*scsi_end_request(struct scsi_cmnd
*cmd
, int uptodate
,
589 int bytes
, int requeue
)
591 request_queue_t
*q
= cmd
->device
->request_queue
;
592 struct request
*req
= cmd
->request
;
596 * If there are blocks left over at the end, set up the command
597 * to queue the remainder of them.
599 if (end_that_request_chunk(req
, uptodate
, bytes
)) {
600 int leftover
= (req
->hard_nr_sectors
<< 9);
602 if (blk_pc_request(req
))
603 leftover
= req
->data_len
;
605 /* kill remainder if no retrys */
606 if (!uptodate
&& blk_noretry_request(req
))
607 end_that_request_chunk(req
, 0, leftover
);
611 * Bleah. Leftovers again. Stick the
612 * leftovers in the front of the
613 * queue, and goose the queue again.
615 scsi_requeue_command(q
, cmd
);
622 add_disk_randomness(req
->rq_disk
);
624 spin_lock_irqsave(q
->queue_lock
, flags
);
625 if (blk_rq_tagged(req
))
626 blk_queue_end_tag(q
, req
);
627 end_that_request_last(req
);
628 spin_unlock_irqrestore(q
->queue_lock
, flags
);
631 * This will goose the queue request function at the end, so we don't
632 * need to worry about launching another command.
634 scsi_next_command(cmd
);
638 static struct scatterlist
*scsi_alloc_sgtable(struct scsi_cmnd
*cmd
, gfp_t gfp_mask
)
640 struct scsi_host_sg_pool
*sgp
;
641 struct scatterlist
*sgl
;
643 BUG_ON(!cmd
->use_sg
);
645 switch (cmd
->use_sg
) {
655 #if (SCSI_MAX_PHYS_SEGMENTS > 32)
659 #if (SCSI_MAX_PHYS_SEGMENTS > 64)
663 #if (SCSI_MAX_PHYS_SEGMENTS > 128)
674 sgp
= scsi_sg_pools
+ cmd
->sglist_len
;
675 sgl
= mempool_alloc(sgp
->pool
, gfp_mask
);
679 static void scsi_free_sgtable(struct scatterlist
*sgl
, int index
)
681 struct scsi_host_sg_pool
*sgp
;
683 BUG_ON(index
>= SG_MEMPOOL_NR
);
685 sgp
= scsi_sg_pools
+ index
;
686 mempool_free(sgl
, sgp
->pool
);
690 * Function: scsi_release_buffers()
692 * Purpose: Completion processing for block device I/O requests.
694 * Arguments: cmd - command that we are bailing.
696 * Lock status: Assumed that no lock is held upon entry.
700 * Notes: In the event that an upper level driver rejects a
701 * command, we must release resources allocated during
702 * the __init_io() function. Primarily this would involve
703 * the scatter-gather table, and potentially any bounce
706 static void scsi_release_buffers(struct scsi_cmnd
*cmd
)
708 struct request
*req
= cmd
->request
;
711 * Free up any indirection buffers we allocated for DMA purposes.
714 scsi_free_sgtable(cmd
->request_buffer
, cmd
->sglist_len
);
715 else if (cmd
->request_buffer
!= req
->buffer
)
716 kfree(cmd
->request_buffer
);
719 * Zero these out. They now point to freed memory, and it is
720 * dangerous to hang onto the pointers.
724 cmd
->request_buffer
= NULL
;
725 cmd
->request_bufflen
= 0;
729 * Function: scsi_io_completion()
731 * Purpose: Completion processing for block device I/O requests.
733 * Arguments: cmd - command that is finished.
735 * Lock status: Assumed that no lock is held upon entry.
739 * Notes: This function is matched in terms of capabilities to
740 * the function that created the scatter-gather list.
741 * In other words, if there are no bounce buffers
742 * (the normal case for most drivers), we don't need
743 * the logic to deal with cleaning up afterwards.
745 * We must do one of several things here:
747 * a) Call scsi_end_request. This will finish off the
748 * specified number of sectors. If we are done, the
749 * command block will be released, and the queue
750 * function will be goosed. If we are not done, then
751 * scsi_end_request will directly goose the queue.
753 * b) We can just use scsi_requeue_command() here. This would
754 * be used if we just wanted to retry, for example.
756 void scsi_io_completion(struct scsi_cmnd
*cmd
, unsigned int good_bytes
,
757 unsigned int block_bytes
)
759 int result
= cmd
->result
;
760 int this_count
= cmd
->bufflen
;
761 request_queue_t
*q
= cmd
->device
->request_queue
;
762 struct request
*req
= cmd
->request
;
763 int clear_errors
= 1;
764 struct scsi_sense_hdr sshdr
;
766 int sense_deferred
= 0;
768 if (blk_complete_barrier_rq(q
, req
, good_bytes
>> 9))
772 * Free up any indirection buffers we allocated for DMA purposes.
773 * For the case of a READ, we need to copy the data out of the
774 * bounce buffer and into the real buffer.
777 scsi_free_sgtable(cmd
->buffer
, cmd
->sglist_len
);
778 else if (cmd
->buffer
!= req
->buffer
) {
779 if (rq_data_dir(req
) == READ
) {
781 char *to
= bio_kmap_irq(req
->bio
, &flags
);
782 memcpy(to
, cmd
->buffer
, cmd
->bufflen
);
783 bio_kunmap_irq(to
, &flags
);
789 sense_valid
= scsi_command_normalize_sense(cmd
, &sshdr
);
791 sense_deferred
= scsi_sense_is_deferred(&sshdr
);
793 if (blk_pc_request(req
)) { /* SG_IO ioctl from block level */
794 req
->errors
= result
;
797 if (sense_valid
&& req
->sense
) {
799 * SG_IO wants current and deferred errors
801 int len
= 8 + cmd
->sense_buffer
[7];
803 if (len
> SCSI_SENSE_BUFFERSIZE
)
804 len
= SCSI_SENSE_BUFFERSIZE
;
805 memcpy(req
->sense
, cmd
->sense_buffer
, len
);
806 req
->sense_len
= len
;
809 req
->data_len
= cmd
->resid
;
813 * Zero these out. They now point to freed memory, and it is
814 * dangerous to hang onto the pointers.
818 cmd
->request_buffer
= NULL
;
819 cmd
->request_bufflen
= 0;
822 * Next deal with any sectors which we were able to correctly
825 if (good_bytes
>= 0) {
826 SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, %d bytes done.\n",
827 req
->nr_sectors
, good_bytes
));
828 SCSI_LOG_HLCOMPLETE(1, printk("use_sg is %d\n", cmd
->use_sg
));
833 * If multiple sectors are requested in one buffer, then
834 * they will have been finished off by the first command.
835 * If not, then we have a multi-buffer command.
837 * If block_bytes != 0, it means we had a medium error
838 * of some sort, and that we want to mark some number of
839 * sectors as not uptodate. Thus we want to inhibit
840 * requeueing right here - we will requeue down below
841 * when we handle the bad sectors.
845 * If the command completed without error, then either
846 * finish off the rest of the command, or start a new one.
848 if (scsi_end_request(cmd
, 1, good_bytes
, result
== 0) == NULL
)
852 * Now, if we were good little boys and girls, Santa left us a request
853 * sense buffer. We can extract information from this, so we
854 * can choose a block to remap, etc.
856 if (sense_valid
&& !sense_deferred
) {
857 switch (sshdr
.sense_key
) {
859 if (cmd
->device
->removable
) {
860 /* detected disc change. set a bit
861 * and quietly refuse further access.
863 cmd
->device
->changed
= 1;
864 scsi_end_request(cmd
, 0,
869 * Must have been a power glitch, or a
870 * bus reset. Could not have been a
871 * media change, so we just retry the
872 * request and see what happens.
874 scsi_requeue_command(q
, cmd
);
878 case ILLEGAL_REQUEST
:
880 * If we had an ILLEGAL REQUEST returned, then we may
881 * have performed an unsupported command. The only
882 * thing this should be would be a ten byte read where
883 * only a six byte read was supported. Also, on a
884 * system where READ CAPACITY failed, we may have read
885 * past the end of the disk.
887 if ((cmd
->device
->use_10_for_rw
&&
888 sshdr
.asc
== 0x20 && sshdr
.ascq
== 0x00) &&
889 (cmd
->cmnd
[0] == READ_10
||
890 cmd
->cmnd
[0] == WRITE_10
)) {
891 cmd
->device
->use_10_for_rw
= 0;
893 * This will cause a retry with a 6-byte
896 scsi_requeue_command(q
, cmd
);
899 scsi_end_request(cmd
, 0, this_count
, 1);
905 * If the device is in the process of becoming ready,
908 if (sshdr
.asc
== 0x04 && sshdr
.ascq
== 0x01) {
909 scsi_requeue_command(q
, cmd
);
912 if (!(req
->flags
& REQ_QUIET
))
913 scmd_printk(KERN_INFO
, cmd
,
914 "Device not ready.\n");
915 scsi_end_request(cmd
, 0, this_count
, 1);
917 case VOLUME_OVERFLOW
:
918 if (!(req
->flags
& REQ_QUIET
)) {
919 scmd_printk(KERN_INFO
, cmd
,
920 "Volume overflow, CDB: ");
921 __scsi_print_command(cmd
->data_cmnd
);
922 scsi_print_sense("", cmd
);
924 scsi_end_request(cmd
, 0, block_bytes
, 1);
929 } /* driver byte != 0 */
930 if (host_byte(result
) == DID_RESET
) {
932 * Third party bus reset or reset for error
933 * recovery reasons. Just retry the request
934 * and see what happens.
936 scsi_requeue_command(q
, cmd
);
940 if (!(req
->flags
& REQ_QUIET
)) {
941 scmd_printk(KERN_INFO
, cmd
,
942 "SCSI error: return code = 0x%x\n", result
);
944 if (driver_byte(result
) & DRIVER_SENSE
)
945 scsi_print_sense("", cmd
);
948 * Mark a single buffer as not uptodate. Queue the remainder.
949 * We sometimes get this cruft in the event that a medium error
950 * isn't properly reported.
952 block_bytes
= req
->hard_cur_sectors
<< 9;
954 block_bytes
= req
->data_len
;
955 scsi_end_request(cmd
, 0, block_bytes
, 1);
958 EXPORT_SYMBOL(scsi_io_completion
);
961 * Function: scsi_init_io()
963 * Purpose: SCSI I/O initialize function.
965 * Arguments: cmd - Command descriptor we wish to initialize
967 * Returns: 0 on success
968 * BLKPREP_DEFER if the failure is retryable
969 * BLKPREP_KILL if the failure is fatal
971 static int scsi_init_io(struct scsi_cmnd
*cmd
)
973 struct request
*req
= cmd
->request
;
974 struct scatterlist
*sgpnt
;
978 * if this is a rq->data based REQ_BLOCK_PC, setup for a non-sg xfer
980 if ((req
->flags
& REQ_BLOCK_PC
) && !req
->bio
) {
981 cmd
->request_bufflen
= req
->data_len
;
982 cmd
->request_buffer
= req
->data
;
983 req
->buffer
= req
->data
;
989 * we used to not use scatter-gather for single segment request,
990 * but now we do (it makes highmem I/O easier to support without
993 cmd
->use_sg
= req
->nr_phys_segments
;
996 * if sg table allocation fails, requeue request later.
998 sgpnt
= scsi_alloc_sgtable(cmd
, GFP_ATOMIC
);
999 if (unlikely(!sgpnt
)) {
1000 scsi_unprep_request(req
);
1001 return BLKPREP_DEFER
;
1004 cmd
->request_buffer
= (char *) sgpnt
;
1005 cmd
->request_bufflen
= req
->nr_sectors
<< 9;
1006 if (blk_pc_request(req
))
1007 cmd
->request_bufflen
= req
->data_len
;
1011 * Next, walk the list, and fill in the addresses and sizes of
1014 count
= blk_rq_map_sg(req
->q
, req
, cmd
->request_buffer
);
1017 * mapped well, send it off
1019 if (likely(count
<= cmd
->use_sg
)) {
1020 cmd
->use_sg
= count
;
1024 printk(KERN_ERR
"Incorrect number of segments after building list\n");
1025 printk(KERN_ERR
"counted %d, received %d\n", count
, cmd
->use_sg
);
1026 printk(KERN_ERR
"req nr_sec %lu, cur_nr_sec %u\n", req
->nr_sectors
,
1027 req
->current_nr_sectors
);
1029 /* release the command and kill it */
1030 scsi_release_buffers(cmd
);
1031 scsi_put_command(cmd
);
1032 return BLKPREP_KILL
;
1035 static int scsi_prepare_flush_fn(request_queue_t
*q
, struct request
*rq
)
1037 struct scsi_device
*sdev
= q
->queuedata
;
1038 struct scsi_driver
*drv
;
1040 if (sdev
->sdev_state
== SDEV_RUNNING
) {
1041 drv
= *(struct scsi_driver
**) rq
->rq_disk
->private_data
;
1043 if (drv
->prepare_flush
)
1044 return drv
->prepare_flush(q
, rq
);
1050 static void scsi_end_flush_fn(request_queue_t
*q
, struct request
*rq
)
1052 struct scsi_device
*sdev
= q
->queuedata
;
1053 struct request
*flush_rq
= rq
->end_io_data
;
1054 struct scsi_driver
*drv
;
1056 if (flush_rq
->errors
) {
1057 printk("scsi: barrier error, disabling flush support\n");
1058 blk_queue_ordered(q
, QUEUE_ORDERED_NONE
);
1061 if (sdev
->sdev_state
== SDEV_RUNNING
) {
1062 drv
= *(struct scsi_driver
**) rq
->rq_disk
->private_data
;
1063 drv
->end_flush(q
, rq
);
1067 static int scsi_issue_flush_fn(request_queue_t
*q
, struct gendisk
*disk
,
1068 sector_t
*error_sector
)
1070 struct scsi_device
*sdev
= q
->queuedata
;
1071 struct scsi_driver
*drv
;
1073 if (sdev
->sdev_state
!= SDEV_RUNNING
)
1076 drv
= *(struct scsi_driver
**) disk
->private_data
;
1077 if (drv
->issue_flush
)
1078 return drv
->issue_flush(&sdev
->sdev_gendev
, error_sector
);
1083 static void scsi_generic_done(struct scsi_cmnd
*cmd
)
1085 BUG_ON(!blk_pc_request(cmd
->request
));
1086 scsi_io_completion(cmd
, cmd
->result
== 0 ? cmd
->bufflen
: 0, 0);
1089 static int scsi_prep_fn(struct request_queue
*q
, struct request
*req
)
1091 struct scsi_device
*sdev
= q
->queuedata
;
1092 struct scsi_cmnd
*cmd
;
1093 int specials_only
= 0;
1096 * Just check to see if the device is online. If it isn't, we
1097 * refuse to process any commands. The device must be brought
1098 * online before trying any recovery commands
1100 if (unlikely(!scsi_device_online(sdev
))) {
1101 sdev_printk(KERN_ERR
, sdev
,
1102 "rejecting I/O to offline device\n");
1105 if (unlikely(sdev
->sdev_state
!= SDEV_RUNNING
)) {
1106 /* OK, we're not in a running state don't prep
1108 if (sdev
->sdev_state
== SDEV_DEL
) {
1109 /* Device is fully deleted, no commands
1110 * at all allowed down */
1111 sdev_printk(KERN_ERR
, sdev
,
1112 "rejecting I/O to dead device\n");
1115 /* OK, we only allow special commands (i.e. not
1116 * user initiated ones */
1117 specials_only
= sdev
->sdev_state
;
1121 * Find the actual device driver associated with this command.
1122 * The SPECIAL requests are things like character device or
1123 * ioctls, which did not originate from ll_rw_blk. Note that
1124 * the special field is also used to indicate the cmd for
1125 * the remainder of a partially fulfilled request that can
1126 * come up when there is a medium error. We have to treat
1127 * these two cases differently. We differentiate by looking
1128 * at request->cmd, as this tells us the real story.
1130 if (req
->flags
& REQ_SPECIAL
&& req
->special
) {
1131 struct scsi_request
*sreq
= req
->special
;
1133 if (sreq
->sr_magic
== SCSI_REQ_MAGIC
) {
1134 cmd
= scsi_get_command(sreq
->sr_device
, GFP_ATOMIC
);
1137 scsi_init_cmd_from_req(cmd
, sreq
);
1140 } else if (req
->flags
& (REQ_CMD
| REQ_BLOCK_PC
)) {
1142 if(unlikely(specials_only
) && !(req
->flags
& REQ_SPECIAL
)) {
1143 if(specials_only
== SDEV_QUIESCE
||
1144 specials_only
== SDEV_BLOCK
)
1147 sdev_printk(KERN_ERR
, sdev
,
1148 "rejecting I/O to device being removed\n");
1154 * Now try and find a command block that we can use.
1156 if (!req
->special
) {
1157 cmd
= scsi_get_command(sdev
, GFP_ATOMIC
);
1163 /* pull a tag out of the request if we have one */
1164 cmd
->tag
= req
->tag
;
1166 blk_dump_rq_flags(req
, "SCSI bad req");
1170 /* note the overloading of req->special. When the tag
1171 * is active it always means cmd. If the tag goes
1172 * back for re-queueing, it may be reset */
1177 * FIXME: drop the lock here because the functions below
1178 * expect to be called without the queue lock held. Also,
1179 * previously, we dequeued the request before dropping the
1180 * lock. We hope REQ_STARTED prevents anything untoward from
1183 if (req
->flags
& (REQ_CMD
| REQ_BLOCK_PC
)) {
1184 struct scsi_driver
*drv
;
1188 * This will do a couple of things:
1189 * 1) Fill in the actual SCSI command.
1190 * 2) Fill in any other upper-level specific fields
1193 * If this returns 0, it means that the request failed
1194 * (reading past end of disk, reading offline device,
1195 * etc). This won't actually talk to the device, but
1196 * some kinds of consistency checking may cause the
1197 * request to be rejected immediately.
1201 * This sets up the scatter-gather table (allocating if
1204 ret
= scsi_init_io(cmd
);
1206 /* For BLKPREP_KILL/DEFER the cmd was released */
1214 * Initialize the actual SCSI command for this request.
1217 drv
= *(struct scsi_driver
**)req
->rq_disk
->private_data
;
1218 if (unlikely(!drv
->init_command(cmd
))) {
1219 scsi_release_buffers(cmd
);
1220 scsi_put_command(cmd
);
1224 memcpy(cmd
->cmnd
, req
->cmd
, sizeof(cmd
->cmnd
));
1225 cmd
->cmd_len
= req
->cmd_len
;
1226 if (rq_data_dir(req
) == WRITE
)
1227 cmd
->sc_data_direction
= DMA_TO_DEVICE
;
1228 else if (req
->data_len
)
1229 cmd
->sc_data_direction
= DMA_FROM_DEVICE
;
1231 cmd
->sc_data_direction
= DMA_NONE
;
1233 cmd
->transfersize
= req
->data_len
;
1235 cmd
->timeout_per_command
= req
->timeout
;
1236 cmd
->done
= scsi_generic_done
;
1241 * The request is now prepped, no need to come back here
1243 req
->flags
|= REQ_DONTPREP
;
1247 /* If we defer, the elv_next_request() returns NULL, but the
1248 * queue must be restarted, so we plug here if no returning
1249 * command will automatically do that. */
1250 if (sdev
->device_busy
== 0)
1252 return BLKPREP_DEFER
;
1254 req
->errors
= DID_NO_CONNECT
<< 16;
1255 return BLKPREP_KILL
;
1259 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1262 * Called with the queue_lock held.
1264 static inline int scsi_dev_queue_ready(struct request_queue
*q
,
1265 struct scsi_device
*sdev
)
1267 if (sdev
->device_busy
>= sdev
->queue_depth
)
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"));
1282 if (sdev
->device_blocked
)
1289 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1290 * return 0. We must end up running the queue again whenever 0 is
1291 * returned, else IO can hang.
1293 * Called with host_lock held.
1295 static inline int scsi_host_queue_ready(struct request_queue
*q
,
1296 struct Scsi_Host
*shost
,
1297 struct scsi_device
*sdev
)
1299 if (scsi_host_in_recovery(shost
))
1301 if (shost
->host_busy
== 0 && shost
->host_blocked
) {
1303 * unblock after host_blocked iterates to zero
1305 if (--shost
->host_blocked
== 0) {
1307 printk("scsi%d unblocking host at zero depth\n",
1314 if ((shost
->can_queue
> 0 && shost
->host_busy
>= shost
->can_queue
) ||
1315 shost
->host_blocked
|| shost
->host_self_blocked
) {
1316 if (list_empty(&sdev
->starved_entry
))
1317 list_add_tail(&sdev
->starved_entry
, &shost
->starved_list
);
1321 /* We're OK to process the command, so we can't be starved */
1322 if (!list_empty(&sdev
->starved_entry
))
1323 list_del_init(&sdev
->starved_entry
);
1329 * Kill a request for a dead device
1331 static void scsi_kill_request(struct request
*req
, request_queue_t
*q
)
1333 struct scsi_cmnd
*cmd
= req
->special
;
1335 blkdev_dequeue_request(req
);
1337 if (unlikely(cmd
== NULL
)) {
1338 printk(KERN_CRIT
"impossible request in %s.\n",
1343 scsi_init_cmd_errh(cmd
);
1344 cmd
->result
= DID_NO_CONNECT
<< 16;
1345 atomic_inc(&cmd
->device
->iorequest_cnt
);
1350 * Function: scsi_request_fn()
1352 * Purpose: Main strategy routine for SCSI.
1354 * Arguments: q - Pointer to actual queue.
1358 * Lock status: IO request lock assumed to be held when called.
1360 static void scsi_request_fn(struct request_queue
*q
)
1362 struct scsi_device
*sdev
= q
->queuedata
;
1363 struct Scsi_Host
*shost
;
1364 struct scsi_cmnd
*cmd
;
1365 struct request
*req
;
1368 printk("scsi: killing requests for dead queue\n");
1369 while ((req
= elv_next_request(q
)) != NULL
)
1370 scsi_kill_request(req
, q
);
1374 if(!get_device(&sdev
->sdev_gendev
))
1375 /* We must be tearing the block queue down already */
1379 * To start with, we keep looping until the queue is empty, or until
1380 * the host is no longer able to accept any more requests.
1383 while (!blk_queue_plugged(q
)) {
1386 * get next queueable request. We do this early to make sure
1387 * that the request is fully prepared even if we cannot
1390 req
= elv_next_request(q
);
1391 if (!req
|| !scsi_dev_queue_ready(q
, sdev
))
1394 if (unlikely(!scsi_device_online(sdev
))) {
1395 sdev_printk(KERN_ERR
, sdev
,
1396 "rejecting I/O to offline device\n");
1397 scsi_kill_request(req
, q
);
1403 * Remove the request from the request list.
1405 if (!(blk_queue_tagged(q
) && !blk_queue_start_tag(q
, req
)))
1406 blkdev_dequeue_request(req
);
1407 sdev
->device_busy
++;
1409 spin_unlock(q
->queue_lock
);
1411 if (unlikely(cmd
== NULL
)) {
1412 printk(KERN_CRIT
"impossible request in %s.\n"
1413 "please mail a stack trace to "
1414 "linux-scsi@vger.kernel.org",
1418 spin_lock(shost
->host_lock
);
1420 if (!scsi_host_queue_ready(q
, shost
, sdev
))
1422 if (sdev
->single_lun
) {
1423 if (scsi_target(sdev
)->starget_sdev_user
&&
1424 scsi_target(sdev
)->starget_sdev_user
!= sdev
)
1426 scsi_target(sdev
)->starget_sdev_user
= sdev
;
1431 * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will
1432 * take the lock again.
1434 spin_unlock_irq(shost
->host_lock
);
1437 * Finally, initialize any error handling parameters, and set up
1438 * the timers for timeouts.
1440 scsi_init_cmd_errh(cmd
);
1443 * Dispatch the command to the low-level driver.
1445 rtn
= scsi_dispatch_cmd(cmd
);
1446 spin_lock_irq(q
->queue_lock
);
1448 /* we're refusing the command; because of
1449 * the way locks get dropped, we need to
1450 * check here if plugging is required */
1451 if(sdev
->device_busy
== 0)
1461 spin_unlock_irq(shost
->host_lock
);
1464 * lock q, handle tag, requeue req, and decrement device_busy. We
1465 * must return with queue_lock held.
1467 * Decrementing device_busy without checking it is OK, as all such
1468 * cases (host limits or settings) should run the queue at some
1471 spin_lock_irq(q
->queue_lock
);
1472 blk_requeue_request(q
, req
);
1473 sdev
->device_busy
--;
1474 if(sdev
->device_busy
== 0)
1477 /* must be careful here...if we trigger the ->remove() function
1478 * we cannot be holding the q lock */
1479 spin_unlock_irq(q
->queue_lock
);
1480 put_device(&sdev
->sdev_gendev
);
1481 spin_lock_irq(q
->queue_lock
);
1484 u64
scsi_calculate_bounce_limit(struct Scsi_Host
*shost
)
1486 struct device
*host_dev
;
1487 u64 bounce_limit
= 0xffffffff;
1489 if (shost
->unchecked_isa_dma
)
1490 return BLK_BOUNCE_ISA
;
1492 * Platforms with virtual-DMA translation
1493 * hardware have no practical limit.
1495 if (!PCI_DMA_BUS_IS_PHYS
)
1496 return BLK_BOUNCE_ANY
;
1498 host_dev
= scsi_get_device(shost
);
1499 if (host_dev
&& host_dev
->dma_mask
)
1500 bounce_limit
= *host_dev
->dma_mask
;
1502 return bounce_limit
;
1504 EXPORT_SYMBOL(scsi_calculate_bounce_limit
);
1506 struct request_queue
*scsi_alloc_queue(struct scsi_device
*sdev
)
1508 struct Scsi_Host
*shost
= sdev
->host
;
1509 struct request_queue
*q
;
1511 q
= blk_init_queue(scsi_request_fn
, NULL
);
1515 blk_queue_prep_rq(q
, scsi_prep_fn
);
1517 blk_queue_max_hw_segments(q
, shost
->sg_tablesize
);
1518 blk_queue_max_phys_segments(q
, SCSI_MAX_PHYS_SEGMENTS
);
1519 blk_queue_max_sectors(q
, shost
->max_sectors
);
1520 blk_queue_bounce_limit(q
, scsi_calculate_bounce_limit(shost
));
1521 blk_queue_segment_boundary(q
, shost
->dma_boundary
);
1522 blk_queue_issue_flush_fn(q
, scsi_issue_flush_fn
);
1525 * ordered tags are superior to flush ordering
1527 if (shost
->ordered_tag
)
1528 blk_queue_ordered(q
, QUEUE_ORDERED_TAG
);
1529 else if (shost
->ordered_flush
) {
1530 blk_queue_ordered(q
, QUEUE_ORDERED_FLUSH
);
1531 q
->prepare_flush_fn
= scsi_prepare_flush_fn
;
1532 q
->end_flush_fn
= scsi_end_flush_fn
;
1535 if (!shost
->use_clustering
)
1536 clear_bit(QUEUE_FLAG_CLUSTER
, &q
->queue_flags
);
1540 void scsi_free_queue(struct request_queue
*q
)
1542 blk_cleanup_queue(q
);
1546 * Function: scsi_block_requests()
1548 * Purpose: Utility function used by low-level drivers to prevent further
1549 * commands from being queued to the device.
1551 * Arguments: shost - Host in question
1555 * Lock status: No locks are assumed held.
1557 * Notes: There is no timer nor any other means by which the requests
1558 * get unblocked other than the low-level driver calling
1559 * scsi_unblock_requests().
1561 void scsi_block_requests(struct Scsi_Host
*shost
)
1563 shost
->host_self_blocked
= 1;
1565 EXPORT_SYMBOL(scsi_block_requests
);
1568 * Function: scsi_unblock_requests()
1570 * Purpose: Utility function used by low-level drivers to allow further
1571 * commands from being queued to the device.
1573 * Arguments: shost - Host in question
1577 * Lock status: No locks are assumed held.
1579 * Notes: There is no timer nor any other means by which the requests
1580 * get unblocked other than the low-level driver calling
1581 * scsi_unblock_requests().
1583 * This is done as an API function so that changes to the
1584 * internals of the scsi mid-layer won't require wholesale
1585 * changes to drivers that use this feature.
1587 void scsi_unblock_requests(struct Scsi_Host
*shost
)
1589 shost
->host_self_blocked
= 0;
1590 scsi_run_host_queues(shost
);
1592 EXPORT_SYMBOL(scsi_unblock_requests
);
1594 int __init
scsi_init_queue(void)
1598 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
1599 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
1600 int size
= sgp
->size
* sizeof(struct scatterlist
);
1602 sgp
->slab
= kmem_cache_create(sgp
->name
, size
, 0,
1603 SLAB_HWCACHE_ALIGN
, NULL
, NULL
);
1605 printk(KERN_ERR
"SCSI: can't init sg slab %s\n",
1609 sgp
->pool
= mempool_create(SG_MEMPOOL_SIZE
,
1610 mempool_alloc_slab
, mempool_free_slab
,
1613 printk(KERN_ERR
"SCSI: can't init sg mempool %s\n",
1621 void scsi_exit_queue(void)
1625 for (i
= 0; i
< SG_MEMPOOL_NR
; i
++) {
1626 struct scsi_host_sg_pool
*sgp
= scsi_sg_pools
+ i
;
1627 mempool_destroy(sgp
->pool
);
1628 kmem_cache_destroy(sgp
->slab
);
1632 * scsi_mode_sense - issue a mode sense, falling back from 10 to
1633 * six bytes if necessary.
1634 * @sdev: SCSI device to be queried
1635 * @dbd: set if mode sense will allow block descriptors to be returned
1636 * @modepage: mode page being requested
1637 * @buffer: request buffer (may not be smaller than eight bytes)
1638 * @len: length of request buffer.
1639 * @timeout: command timeout
1640 * @retries: number of retries before failing
1641 * @data: returns a structure abstracting the mode header data
1642 * @sense: place to put sense data (or NULL if no sense to be collected).
1643 * must be SCSI_SENSE_BUFFERSIZE big.
1645 * Returns zero if unsuccessful, or the header offset (either 4
1646 * or 8 depending on whether a six or ten byte command was
1647 * issued) if successful.
1650 scsi_mode_sense(struct scsi_device
*sdev
, int dbd
, int modepage
,
1651 unsigned char *buffer
, int len
, int timeout
, int retries
,
1652 struct scsi_mode_data
*data
, struct scsi_sense_hdr
*sshdr
) {
1653 unsigned char cmd
[12];
1657 struct scsi_sense_hdr my_sshdr
;
1659 memset(data
, 0, sizeof(*data
));
1660 memset(&cmd
[0], 0, 12);
1661 cmd
[1] = dbd
& 0x18; /* allows DBD and LLBA bits */
1664 /* caller might not be interested in sense, but we need it */
1669 use_10_for_ms
= sdev
->use_10_for_ms
;
1671 if (use_10_for_ms
) {
1675 cmd
[0] = MODE_SENSE_10
;
1682 cmd
[0] = MODE_SENSE
;
1687 memset(buffer
, 0, len
);
1689 result
= scsi_execute_req(sdev
, cmd
, DMA_FROM_DEVICE
, buffer
, len
,
1690 sshdr
, timeout
, retries
);
1692 /* This code looks awful: what it's doing is making sure an
1693 * ILLEGAL REQUEST sense return identifies the actual command
1694 * byte as the problem. MODE_SENSE commands can return
1695 * ILLEGAL REQUEST if the code page isn't supported */
1697 if (use_10_for_ms
&& !scsi_status_is_good(result
) &&
1698 (driver_byte(result
) & DRIVER_SENSE
)) {
1699 if (scsi_sense_valid(sshdr
)) {
1700 if ((sshdr
->sense_key
== ILLEGAL_REQUEST
) &&
1701 (sshdr
->asc
== 0x20) && (sshdr
->ascq
== 0)) {
1703 * Invalid command operation code
1705 sdev
->use_10_for_ms
= 0;
1711 if(scsi_status_is_good(result
)) {
1712 data
->header_length
= header_length
;
1714 data
->length
= buffer
[0]*256 + buffer
[1] + 2;
1715 data
->medium_type
= buffer
[2];
1716 data
->device_specific
= buffer
[3];
1717 data
->longlba
= buffer
[4] & 0x01;
1718 data
->block_descriptor_length
= buffer
[6]*256
1721 data
->length
= buffer
[0] + 1;
1722 data
->medium_type
= buffer
[1];
1723 data
->device_specific
= buffer
[2];
1724 data
->block_descriptor_length
= buffer
[3];
1730 EXPORT_SYMBOL(scsi_mode_sense
);
1733 scsi_test_unit_ready(struct scsi_device
*sdev
, int timeout
, int retries
)
1736 TEST_UNIT_READY
, 0, 0, 0, 0, 0,
1738 struct scsi_sense_hdr sshdr
;
1741 result
= scsi_execute_req(sdev
, cmd
, DMA_NONE
, NULL
, 0, &sshdr
,
1744 if ((driver_byte(result
) & DRIVER_SENSE
) && sdev
->removable
) {
1746 if ((scsi_sense_valid(&sshdr
)) &&
1747 ((sshdr
.sense_key
== UNIT_ATTENTION
) ||
1748 (sshdr
.sense_key
== NOT_READY
))) {
1755 EXPORT_SYMBOL(scsi_test_unit_ready
);
1758 * scsi_device_set_state - Take the given device through the device
1760 * @sdev: scsi device to change the state of.
1761 * @state: state to change to.
1763 * Returns zero if unsuccessful or an error if the requested
1764 * transition is illegal.
1767 scsi_device_set_state(struct scsi_device
*sdev
, enum scsi_device_state state
)
1769 enum scsi_device_state oldstate
= sdev
->sdev_state
;
1771 if (state
== oldstate
)
1776 /* There are no legal states that come back to
1777 * created. This is the manually initialised start
1847 sdev
->sdev_state
= state
;
1851 SCSI_LOG_ERROR_RECOVERY(1,
1852 sdev_printk(KERN_ERR
, sdev
,
1853 "Illegal state transition %s->%s\n",
1854 scsi_device_state_name(oldstate
),
1855 scsi_device_state_name(state
))
1859 EXPORT_SYMBOL(scsi_device_set_state
);
1862 * scsi_device_quiesce - Block user issued commands.
1863 * @sdev: scsi device to quiesce.
1865 * This works by trying to transition to the SDEV_QUIESCE state
1866 * (which must be a legal transition). When the device is in this
1867 * state, only special requests will be accepted, all others will
1868 * be deferred. Since special requests may also be requeued requests,
1869 * a successful return doesn't guarantee the device will be
1870 * totally quiescent.
1872 * Must be called with user context, may sleep.
1874 * Returns zero if unsuccessful or an error if not.
1877 scsi_device_quiesce(struct scsi_device
*sdev
)
1879 int err
= scsi_device_set_state(sdev
, SDEV_QUIESCE
);
1883 scsi_run_queue(sdev
->request_queue
);
1884 while (sdev
->device_busy
) {
1885 msleep_interruptible(200);
1886 scsi_run_queue(sdev
->request_queue
);
1890 EXPORT_SYMBOL(scsi_device_quiesce
);
1893 * scsi_device_resume - Restart user issued commands to a quiesced device.
1894 * @sdev: scsi device to resume.
1896 * Moves the device from quiesced back to running and restarts the
1899 * Must be called with user context, may sleep.
1902 scsi_device_resume(struct scsi_device
*sdev
)
1904 if(scsi_device_set_state(sdev
, SDEV_RUNNING
))
1906 scsi_run_queue(sdev
->request_queue
);
1908 EXPORT_SYMBOL(scsi_device_resume
);
1911 device_quiesce_fn(struct scsi_device
*sdev
, void *data
)
1913 scsi_device_quiesce(sdev
);
1917 scsi_target_quiesce(struct scsi_target
*starget
)
1919 starget_for_each_device(starget
, NULL
, device_quiesce_fn
);
1921 EXPORT_SYMBOL(scsi_target_quiesce
);
1924 device_resume_fn(struct scsi_device
*sdev
, void *data
)
1926 scsi_device_resume(sdev
);
1930 scsi_target_resume(struct scsi_target
*starget
)
1932 starget_for_each_device(starget
, NULL
, device_resume_fn
);
1934 EXPORT_SYMBOL(scsi_target_resume
);
1937 * scsi_internal_device_block - internal function to put a device
1938 * temporarily into the SDEV_BLOCK state
1939 * @sdev: device to block
1941 * Block request made by scsi lld's to temporarily stop all
1942 * scsi commands on the specified device. Called from interrupt
1943 * or normal process context.
1945 * Returns zero if successful or error if not
1948 * This routine transitions the device to the SDEV_BLOCK state
1949 * (which must be a legal transition). When the device is in this
1950 * state, all commands are deferred until the scsi lld reenables
1951 * the device with scsi_device_unblock or device_block_tmo fires.
1952 * This routine assumes the host_lock is held on entry.
1955 scsi_internal_device_block(struct scsi_device
*sdev
)
1957 request_queue_t
*q
= sdev
->request_queue
;
1958 unsigned long flags
;
1961 err
= scsi_device_set_state(sdev
, SDEV_BLOCK
);
1966 * The device has transitioned to SDEV_BLOCK. Stop the
1967 * block layer from calling the midlayer with this device's
1970 spin_lock_irqsave(q
->queue_lock
, flags
);
1972 spin_unlock_irqrestore(q
->queue_lock
, flags
);
1976 EXPORT_SYMBOL_GPL(scsi_internal_device_block
);
1979 * scsi_internal_device_unblock - resume a device after a block request
1980 * @sdev: device to resume
1982 * Called by scsi lld's or the midlayer to restart the device queue
1983 * for the previously suspended scsi device. Called from interrupt or
1984 * normal process context.
1986 * Returns zero if successful or error if not.
1989 * This routine transitions the device to the SDEV_RUNNING state
1990 * (which must be a legal transition) allowing the midlayer to
1991 * goose the queue for this device. This routine assumes the
1992 * host_lock is held upon entry.
1995 scsi_internal_device_unblock(struct scsi_device
*sdev
)
1997 request_queue_t
*q
= sdev
->request_queue
;
1999 unsigned long flags
;
2002 * Try to transition the scsi device to SDEV_RUNNING
2003 * and goose the device queue if successful.
2005 err
= scsi_device_set_state(sdev
, SDEV_RUNNING
);
2009 spin_lock_irqsave(q
->queue_lock
, flags
);
2011 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2015 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock
);
2018 device_block(struct scsi_device
*sdev
, void *data
)
2020 scsi_internal_device_block(sdev
);
2024 target_block(struct device
*dev
, void *data
)
2026 if (scsi_is_target_device(dev
))
2027 starget_for_each_device(to_scsi_target(dev
), NULL
,
2033 scsi_target_block(struct device
*dev
)
2035 if (scsi_is_target_device(dev
))
2036 starget_for_each_device(to_scsi_target(dev
), NULL
,
2039 device_for_each_child(dev
, NULL
, target_block
);
2041 EXPORT_SYMBOL_GPL(scsi_target_block
);
2044 device_unblock(struct scsi_device
*sdev
, void *data
)
2046 scsi_internal_device_unblock(sdev
);
2050 target_unblock(struct device
*dev
, void *data
)
2052 if (scsi_is_target_device(dev
))
2053 starget_for_each_device(to_scsi_target(dev
), NULL
,
2059 scsi_target_unblock(struct device
*dev
)
2061 if (scsi_is_target_device(dev
))
2062 starget_for_each_device(to_scsi_target(dev
), NULL
,
2065 device_for_each_child(dev
, NULL
, target_unblock
);
2067 EXPORT_SYMBOL_GPL(scsi_target_unblock
);