2 * scsi.c Copyright (C) 1992 Drew Eckhardt
3 * Copyright (C) 1993, 1994, 1995, 1999 Eric Youngdale
4 * Copyright (C) 2002, 2003 Christoph Hellwig
6 * generic mid-level SCSI driver
7 * Initial versions: Drew Eckhardt
8 * Subsequent revisions: Eric Youngdale
12 * Bug correction thanks go to :
13 * Rik Faith <faith@cs.unc.edu>
14 * Tommy Thorn <tthorn>
15 * Thomas Wuensche <tw@fgb1.fgb.mw.tu-muenchen.de>
17 * Modified by Eric Youngdale eric@andante.org or ericy@gnu.ai.mit.edu to
18 * add scatter-gather, multiple outstanding request, and other
21 * Native multichannel, wide scsi, /proc/scsi and hot plugging
22 * support added by Michael Neuffer <mike@i-connect.net>
24 * Added request_module("scsi_hostadapter") for kerneld:
25 * (Put an "alias scsi_hostadapter your_hostadapter" in /etc/modprobe.conf)
26 * Bjorn Ekwall <bj0rn@blox.se>
29 * Major improvements to the timeout, abort, and reset processing,
30 * as well as performance modifications for large queue depths by
31 * Leonard N. Zubkoff <lnz@dandelion.com>
33 * Converted cli() code to spinlocks, Ingo Molnar
35 * Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
37 * out_of_space hacks, D. Gilbert (dpg) 990608
40 #include <linux/module.h>
41 #include <linux/moduleparam.h>
42 #include <linux/kernel.h>
43 #include <linux/timer.h>
44 #include <linux/string.h>
45 #include <linux/slab.h>
46 #include <linux/blkdev.h>
47 #include <linux/delay.h>
48 #include <linux/init.h>
49 #include <linux/completion.h>
50 #include <linux/unistd.h>
51 #include <linux/spinlock.h>
52 #include <linux/kmod.h>
53 #include <linux/interrupt.h>
54 #include <linux/notifier.h>
55 #include <linux/cpu.h>
56 #include <linux/mutex.h>
57 #include <linux/async.h>
58 #include <asm/unaligned.h>
60 #include <scsi/scsi.h>
61 #include <scsi/scsi_cmnd.h>
62 #include <scsi/scsi_dbg.h>
63 #include <scsi/scsi_device.h>
64 #include <scsi/scsi_driver.h>
65 #include <scsi/scsi_eh.h>
66 #include <scsi/scsi_host.h>
67 #include <scsi/scsi_tcq.h>
69 #include "scsi_priv.h"
70 #include "scsi_logging.h"
72 #define CREATE_TRACE_POINTS
73 #include <trace/events/scsi.h>
75 static void scsi_done(struct scsi_cmnd
*cmd
);
78 * Definitions and constants.
82 * Note - the initial logging level can be set here to log events at boot time.
83 * After the system is up, you may enable logging via the /proc interface.
85 unsigned int scsi_logging_level
;
86 #if defined(CONFIG_SCSI_LOGGING)
87 EXPORT_SYMBOL(scsi_logging_level
);
90 /* sd, scsi core and power management need to coordinate flushing async actions */
91 ASYNC_DOMAIN(scsi_sd_probe_domain
);
92 EXPORT_SYMBOL(scsi_sd_probe_domain
);
94 /* NB: These are exposed through /proc/scsi/scsi and form part of the ABI.
95 * You may not alter any existing entry (although adding new ones is
96 * encouraged once assigned by ANSI/INCITS T10
98 static const char *const scsi_device_types
[] = {
121 * scsi_device_type - Return 17 char string indicating device type.
122 * @type: type number to look up
125 const char * scsi_device_type(unsigned type
)
128 return "Well-known LUN ";
131 if (type
>= ARRAY_SIZE(scsi_device_types
))
133 return scsi_device_types
[type
];
136 EXPORT_SYMBOL(scsi_device_type
);
138 struct scsi_host_cmd_pool
{
139 struct kmem_cache
*cmd_slab
;
140 struct kmem_cache
*sense_slab
;
144 unsigned int slab_flags
;
148 static struct scsi_host_cmd_pool scsi_cmd_pool
= {
149 .cmd_name
= "scsi_cmd_cache",
150 .sense_name
= "scsi_sense_cache",
151 .slab_flags
= SLAB_HWCACHE_ALIGN
,
154 static struct scsi_host_cmd_pool scsi_cmd_dma_pool
= {
155 .cmd_name
= "scsi_cmd_cache(DMA)",
156 .sense_name
= "scsi_sense_cache(DMA)",
157 .slab_flags
= SLAB_HWCACHE_ALIGN
|SLAB_CACHE_DMA
,
158 .gfp_mask
= __GFP_DMA
,
161 static DEFINE_MUTEX(host_cmd_pool_mutex
);
164 * scsi_host_free_command - internal function to release a command
165 * @shost: host to free the command for
166 * @cmd: command to release
168 * the command must previously have been allocated by
169 * scsi_host_alloc_command.
172 scsi_host_free_command(struct Scsi_Host
*shost
, struct scsi_cmnd
*cmd
)
174 struct scsi_host_cmd_pool
*pool
= shost
->cmd_pool
;
177 kmem_cache_free(scsi_sdb_cache
, cmd
->prot_sdb
);
178 kmem_cache_free(pool
->sense_slab
, cmd
->sense_buffer
);
179 kmem_cache_free(pool
->cmd_slab
, cmd
);
183 * scsi_host_alloc_command - internal function to allocate command
184 * @shost: SCSI host whose pool to allocate from
185 * @gfp_mask: mask for the allocation
187 * Returns a fully allocated command with sense buffer and protection
188 * data buffer (where applicable) or NULL on failure
190 static struct scsi_cmnd
*
191 scsi_host_alloc_command(struct Scsi_Host
*shost
, gfp_t gfp_mask
)
193 struct scsi_host_cmd_pool
*pool
= shost
->cmd_pool
;
194 struct scsi_cmnd
*cmd
;
196 cmd
= kmem_cache_zalloc(pool
->cmd_slab
, gfp_mask
| pool
->gfp_mask
);
200 cmd
->sense_buffer
= kmem_cache_alloc(pool
->sense_slab
,
201 gfp_mask
| pool
->gfp_mask
);
202 if (!cmd
->sense_buffer
)
205 if (scsi_host_get_prot(shost
) >= SHOST_DIX_TYPE0_PROTECTION
) {
206 cmd
->prot_sdb
= kmem_cache_zalloc(scsi_sdb_cache
, gfp_mask
);
208 goto fail_free_sense
;
214 kmem_cache_free(pool
->sense_slab
, cmd
->sense_buffer
);
216 kmem_cache_free(pool
->cmd_slab
, cmd
);
222 * __scsi_get_command - Allocate a struct scsi_cmnd
223 * @shost: host to transmit command
224 * @gfp_mask: allocation mask
226 * Description: allocate a struct scsi_cmd from host's slab, recycling from the
227 * host's free_list if necessary.
229 struct scsi_cmnd
*__scsi_get_command(struct Scsi_Host
*shost
, gfp_t gfp_mask
)
231 struct scsi_cmnd
*cmd
= scsi_host_alloc_command(shost
, gfp_mask
);
233 if (unlikely(!cmd
)) {
236 spin_lock_irqsave(&shost
->free_list_lock
, flags
);
237 if (likely(!list_empty(&shost
->free_list
))) {
238 cmd
= list_entry(shost
->free_list
.next
,
239 struct scsi_cmnd
, list
);
240 list_del_init(&cmd
->list
);
242 spin_unlock_irqrestore(&shost
->free_list_lock
, flags
);
247 buf
= cmd
->sense_buffer
;
248 prot
= cmd
->prot_sdb
;
250 memset(cmd
, 0, sizeof(*cmd
));
252 cmd
->sense_buffer
= buf
;
253 cmd
->prot_sdb
= prot
;
259 EXPORT_SYMBOL_GPL(__scsi_get_command
);
262 * scsi_get_command - Allocate and setup a scsi command block
263 * @dev: parent scsi device
264 * @gfp_mask: allocator flags
266 * Returns: The allocated scsi command structure.
268 struct scsi_cmnd
*scsi_get_command(struct scsi_device
*dev
, gfp_t gfp_mask
)
270 struct scsi_cmnd
*cmd
= __scsi_get_command(dev
->host
, gfp_mask
);
273 if (unlikely(cmd
== NULL
))
277 INIT_LIST_HEAD(&cmd
->list
);
278 INIT_DELAYED_WORK(&cmd
->abort_work
, scmd_eh_abort_handler
);
279 spin_lock_irqsave(&dev
->list_lock
, flags
);
280 list_add_tail(&cmd
->list
, &dev
->cmd_list
);
281 spin_unlock_irqrestore(&dev
->list_lock
, flags
);
282 cmd
->jiffies_at_alloc
= jiffies
;
285 EXPORT_SYMBOL(scsi_get_command
);
288 * __scsi_put_command - Free a struct scsi_cmnd
290 * @cmd: Command to free
292 void __scsi_put_command(struct Scsi_Host
*shost
, struct scsi_cmnd
*cmd
)
296 if (unlikely(list_empty(&shost
->free_list
))) {
297 spin_lock_irqsave(&shost
->free_list_lock
, flags
);
298 if (list_empty(&shost
->free_list
)) {
299 list_add(&cmd
->list
, &shost
->free_list
);
302 spin_unlock_irqrestore(&shost
->free_list_lock
, flags
);
305 if (likely(cmd
!= NULL
))
306 scsi_host_free_command(shost
, cmd
);
308 EXPORT_SYMBOL(__scsi_put_command
);
311 * scsi_put_command - Free a scsi command block
312 * @cmd: command block to free
316 * Notes: The command must not belong to any lists.
318 void scsi_put_command(struct scsi_cmnd
*cmd
)
322 /* serious error if the command hasn't come from a device list */
323 spin_lock_irqsave(&cmd
->device
->list_lock
, flags
);
324 BUG_ON(list_empty(&cmd
->list
));
325 list_del_init(&cmd
->list
);
326 spin_unlock_irqrestore(&cmd
->device
->list_lock
, flags
);
328 cancel_delayed_work(&cmd
->abort_work
);
330 __scsi_put_command(cmd
->device
->host
, cmd
);
332 EXPORT_SYMBOL(scsi_put_command
);
334 static struct scsi_host_cmd_pool
*
335 scsi_find_host_cmd_pool(struct Scsi_Host
*shost
)
337 if (shost
->hostt
->cmd_size
)
338 return shost
->hostt
->cmd_pool
;
339 if (shost
->unchecked_isa_dma
)
340 return &scsi_cmd_dma_pool
;
341 return &scsi_cmd_pool
;
345 scsi_free_host_cmd_pool(struct scsi_host_cmd_pool
*pool
)
347 kfree(pool
->sense_name
);
348 kfree(pool
->cmd_name
);
352 static struct scsi_host_cmd_pool
*
353 scsi_alloc_host_cmd_pool(struct Scsi_Host
*shost
)
355 struct scsi_host_template
*hostt
= shost
->hostt
;
356 struct scsi_host_cmd_pool
*pool
;
358 pool
= kzalloc(sizeof(*pool
), GFP_KERNEL
);
362 pool
->cmd_name
= kasprintf(GFP_KERNEL
, "%s_cmd", hostt
->name
);
363 pool
->sense_name
= kasprintf(GFP_KERNEL
, "%s_sense", hostt
->name
);
364 if (!pool
->cmd_name
|| !pool
->sense_name
) {
365 scsi_free_host_cmd_pool(pool
);
369 pool
->slab_flags
= SLAB_HWCACHE_ALIGN
;
370 if (shost
->unchecked_isa_dma
) {
371 pool
->slab_flags
|= SLAB_CACHE_DMA
;
372 pool
->gfp_mask
= __GFP_DMA
;
377 static struct scsi_host_cmd_pool
*
378 scsi_get_host_cmd_pool(struct Scsi_Host
*shost
)
380 struct scsi_host_template
*hostt
= shost
->hostt
;
381 struct scsi_host_cmd_pool
*retval
= NULL
, *pool
;
382 size_t cmd_size
= sizeof(struct scsi_cmnd
) + hostt
->cmd_size
;
385 * Select a command slab for this host and create it if not
388 mutex_lock(&host_cmd_pool_mutex
);
389 pool
= scsi_find_host_cmd_pool(shost
);
391 pool
= scsi_alloc_host_cmd_pool(shost
);
397 pool
->cmd_slab
= kmem_cache_create(pool
->cmd_name
, cmd_size
, 0,
398 pool
->slab_flags
, NULL
);
402 pool
->sense_slab
= kmem_cache_create(pool
->sense_name
,
403 SCSI_SENSE_BUFFERSIZE
, 0,
404 pool
->slab_flags
, NULL
);
405 if (!pool
->sense_slab
)
412 mutex_unlock(&host_cmd_pool_mutex
);
416 kmem_cache_destroy(pool
->cmd_slab
);
419 scsi_free_host_cmd_pool(pool
);
423 static void scsi_put_host_cmd_pool(struct Scsi_Host
*shost
)
425 struct scsi_host_template
*hostt
= shost
->hostt
;
426 struct scsi_host_cmd_pool
*pool
;
428 mutex_lock(&host_cmd_pool_mutex
);
429 pool
= scsi_find_host_cmd_pool(shost
);
432 * This may happen if a driver has a mismatched get and put
433 * of the command pool; the driver should be implicated in
436 BUG_ON(pool
->users
== 0);
438 if (!--pool
->users
) {
439 kmem_cache_destroy(pool
->cmd_slab
);
440 kmem_cache_destroy(pool
->sense_slab
);
442 scsi_free_host_cmd_pool(pool
);
444 mutex_unlock(&host_cmd_pool_mutex
);
448 * scsi_setup_command_freelist - Setup the command freelist for a scsi host.
449 * @shost: host to allocate the freelist for.
451 * Description: The command freelist protects against system-wide out of memory
452 * deadlock by preallocating one SCSI command structure for each host, so the
453 * system can always write to a swap file on a device associated with that host.
457 int scsi_setup_command_freelist(struct Scsi_Host
*shost
)
459 const gfp_t gfp_mask
= shost
->unchecked_isa_dma
? GFP_DMA
: GFP_KERNEL
;
460 struct scsi_cmnd
*cmd
;
462 spin_lock_init(&shost
->free_list_lock
);
463 INIT_LIST_HEAD(&shost
->free_list
);
465 shost
->cmd_pool
= scsi_get_host_cmd_pool(shost
);
466 if (!shost
->cmd_pool
)
470 * Get one backup command for this host.
472 cmd
= scsi_host_alloc_command(shost
, gfp_mask
);
474 scsi_put_host_cmd_pool(shost
);
475 shost
->cmd_pool
= NULL
;
478 list_add(&cmd
->list
, &shost
->free_list
);
483 * scsi_destroy_command_freelist - Release the command freelist for a scsi host.
484 * @shost: host whose freelist is going to be destroyed
486 void scsi_destroy_command_freelist(struct Scsi_Host
*shost
)
489 * If cmd_pool is NULL the free list was not initialized, so
490 * do not attempt to release resources.
492 if (!shost
->cmd_pool
)
495 while (!list_empty(&shost
->free_list
)) {
496 struct scsi_cmnd
*cmd
;
498 cmd
= list_entry(shost
->free_list
.next
, struct scsi_cmnd
, list
);
499 list_del_init(&cmd
->list
);
500 scsi_host_free_command(shost
, cmd
);
502 shost
->cmd_pool
= NULL
;
503 scsi_put_host_cmd_pool(shost
);
506 #ifdef CONFIG_SCSI_LOGGING
507 void scsi_log_send(struct scsi_cmnd
*cmd
)
512 * If ML QUEUE log level is greater than or equal to:
514 * 1: nothing (match completion)
516 * 2: log opcode + command of all commands
518 * 3: same as 2 plus dump cmd address
520 * 4: same as 3 plus dump extra junk
522 if (unlikely(scsi_logging_level
)) {
523 level
= SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT
,
524 SCSI_LOG_MLQUEUE_BITS
);
526 scmd_printk(KERN_INFO
, cmd
, "Send: ");
528 printk("0x%p ", cmd
);
530 scsi_print_command(cmd
);
532 printk(KERN_INFO
"buffer = 0x%p, bufflen = %d,"
533 " queuecommand 0x%p\n",
534 scsi_sglist(cmd
), scsi_bufflen(cmd
),
535 cmd
->device
->host
->hostt
->queuecommand
);
542 void scsi_log_completion(struct scsi_cmnd
*cmd
, int disposition
)
547 * If ML COMPLETE log level is greater than or equal to:
549 * 1: log disposition, result, opcode + command, and conditionally
550 * sense data for failures or non SUCCESS dispositions.
552 * 2: same as 1 but for all command completions.
554 * 3: same as 2 plus dump cmd address
556 * 4: same as 3 plus dump extra junk
558 if (unlikely(scsi_logging_level
)) {
559 level
= SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT
,
560 SCSI_LOG_MLCOMPLETE_BITS
);
561 if (((level
> 0) && (cmd
->result
|| disposition
!= SUCCESS
)) ||
563 scmd_printk(KERN_INFO
, cmd
, "Done: ");
565 printk("0x%p ", cmd
);
567 * Dump truncated values, so we usually fit within
570 switch (disposition
) {
585 * If called via scsi_times_out.
592 scsi_print_result(cmd
);
593 scsi_print_command(cmd
);
594 if (status_byte(cmd
->result
) & CHECK_CONDITION
)
595 scsi_print_sense("", cmd
);
597 scmd_printk(KERN_INFO
, cmd
,
598 "scsi host busy %d failed %d\n",
599 cmd
->device
->host
->host_busy
,
600 cmd
->device
->host
->host_failed
);
607 * scsi_cmd_get_serial - Assign a serial number to a command
608 * @host: the scsi host
609 * @cmd: command to assign serial number to
611 * Description: a serial number identifies a request for error recovery
612 * and debugging purposes. Protected by the Host_Lock of host.
614 void scsi_cmd_get_serial(struct Scsi_Host
*host
, struct scsi_cmnd
*cmd
)
616 cmd
->serial_number
= host
->cmd_serial_number
++;
617 if (cmd
->serial_number
== 0)
618 cmd
->serial_number
= host
->cmd_serial_number
++;
620 EXPORT_SYMBOL(scsi_cmd_get_serial
);
623 * scsi_dispatch_command - Dispatch a command to the low-level driver.
624 * @cmd: command block we are dispatching.
626 * Return: nonzero return request was rejected and device's queue needs to be
629 int scsi_dispatch_cmd(struct scsi_cmnd
*cmd
)
631 struct Scsi_Host
*host
= cmd
->device
->host
;
634 atomic_inc(&cmd
->device
->iorequest_cnt
);
636 /* check if the device is still usable */
637 if (unlikely(cmd
->device
->sdev_state
== SDEV_DEL
)) {
638 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
639 * returns an immediate error upwards, and signals
640 * that the device is no longer present */
641 cmd
->result
= DID_NO_CONNECT
<< 16;
643 /* return 0 (because the command has been processed) */
647 /* Check to see if the scsi lld made this device blocked. */
648 if (unlikely(scsi_device_blocked(cmd
->device
))) {
650 * in blocked state, the command is just put back on
651 * the device queue. The suspend state has already
652 * blocked the queue so future requests should not
653 * occur until the device transitions out of the
657 scsi_queue_insert(cmd
, SCSI_MLQUEUE_DEVICE_BUSY
);
659 SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
662 * NOTE: rtn is still zero here because we don't need the
663 * queue to be plugged on return (it's already stopped)
669 * If SCSI-2 or lower, store the LUN value in cmnd.
671 if (cmd
->device
->scsi_level
<= SCSI_2
&&
672 cmd
->device
->scsi_level
!= SCSI_UNKNOWN
) {
673 cmd
->cmnd
[1] = (cmd
->cmnd
[1] & 0x1f) |
674 (cmd
->device
->lun
<< 5 & 0xe0);
680 * Before we queue this command, check if the command
681 * length exceeds what the host adapter can handle.
683 if (cmd
->cmd_len
> cmd
->device
->host
->max_cmd_len
) {
685 printk("queuecommand : command too long. "
686 "cdb_size=%d host->max_cmd_len=%d\n",
687 cmd
->cmd_len
, cmd
->device
->host
->max_cmd_len
));
688 cmd
->result
= (DID_ABORT
<< 16);
694 if (unlikely(host
->shost_state
== SHOST_DEL
)) {
695 cmd
->result
= (DID_NO_CONNECT
<< 16);
698 trace_scsi_dispatch_cmd_start(cmd
);
699 cmd
->scsi_done
= scsi_done
;
700 rtn
= host
->hostt
->queuecommand(host
, cmd
);
704 trace_scsi_dispatch_cmd_error(cmd
, rtn
);
705 if (rtn
!= SCSI_MLQUEUE_DEVICE_BUSY
&&
706 rtn
!= SCSI_MLQUEUE_TARGET_BUSY
)
707 rtn
= SCSI_MLQUEUE_HOST_BUSY
;
709 scsi_queue_insert(cmd
, rtn
);
712 printk("queuecommand : request rejected\n"));
716 SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
721 * scsi_done - Invoke completion on finished SCSI command.
722 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
723 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
725 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
726 * which regains ownership of the SCSI command (de facto) from a LLDD, and
727 * calls blk_complete_request() for further processing.
729 * This function is interrupt context safe.
731 static void scsi_done(struct scsi_cmnd
*cmd
)
733 trace_scsi_dispatch_cmd_done(cmd
);
734 blk_complete_request(cmd
->request
);
738 * scsi_finish_command - cleanup and pass command back to upper layer
741 * Description: Pass command off to upper layer for finishing of I/O
742 * request, waking processes that are waiting on results,
745 void scsi_finish_command(struct scsi_cmnd
*cmd
)
747 struct scsi_device
*sdev
= cmd
->device
;
748 struct scsi_target
*starget
= scsi_target(sdev
);
749 struct Scsi_Host
*shost
= sdev
->host
;
750 struct scsi_driver
*drv
;
751 unsigned int good_bytes
;
753 scsi_device_unbusy(sdev
);
756 * Clear the flags which say that the device/host is no longer
757 * capable of accepting new commands. These are set in scsi_queue.c
758 * for both the queue full condition on a device, and for a
759 * host full condition on the host.
761 * XXX(hch): What about locking?
763 shost
->host_blocked
= 0;
764 starget
->target_blocked
= 0;
765 sdev
->device_blocked
= 0;
768 * If we have valid sense information, then some kind of recovery
769 * must have taken place. Make a note of this.
771 if (SCSI_SENSE_VALID(cmd
))
772 cmd
->result
|= (DRIVER_SENSE
<< 24);
774 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO
, sdev
,
775 "Notifying upper driver of completion "
776 "(result %x)\n", cmd
->result
));
778 good_bytes
= scsi_bufflen(cmd
);
779 if (cmd
->request
->cmd_type
!= REQ_TYPE_BLOCK_PC
) {
780 int old_good_bytes
= good_bytes
;
781 drv
= scsi_cmd_to_driver(cmd
);
783 good_bytes
= drv
->done(cmd
);
785 * USB may not give sense identifying bad sector and
786 * simply return a residue instead, so subtract off the
787 * residue if drv->done() error processing indicates no
788 * change to the completion length.
790 if (good_bytes
== old_good_bytes
)
791 good_bytes
-= scsi_get_resid(cmd
);
793 scsi_io_completion(cmd
, good_bytes
);
795 EXPORT_SYMBOL(scsi_finish_command
);
798 * scsi_adjust_queue_depth - Let low level drivers change a device's queue depth
799 * @sdev: SCSI Device in question
800 * @tagged: Do we use tagged queueing (non-0) or do we treat
801 * this device as an untagged device (0)
802 * @tags: Number of tags allowed if tagged queueing enabled,
803 * or number of commands the low level driver can
804 * queue up in non-tagged mode (as per cmd_per_lun).
808 * Lock Status: None held on entry
810 * Notes: Low level drivers may call this at any time and we will do
811 * the right thing depending on whether or not the device is
812 * currently active and whether or not it even has the
813 * command blocks built yet.
815 void scsi_adjust_queue_depth(struct scsi_device
*sdev
, int tagged
, int tags
)
820 * refuse to set tagged depth to an unworkable size
825 spin_lock_irqsave(sdev
->request_queue
->queue_lock
, flags
);
828 * Check to see if the queue is managed by the block layer.
829 * If it is, and we fail to adjust the depth, exit.
831 * Do not resize the tag map if it is a host wide share bqt,
832 * because the size should be the hosts's can_queue. If there
833 * is more IO than the LLD's can_queue (so there are not enuogh
834 * tags) request_fn's host queue ready check will handle it.
836 if (!sdev
->host
->bqt
) {
837 if (blk_queue_tagged(sdev
->request_queue
) &&
838 blk_queue_resize_tags(sdev
->request_queue
, tags
) != 0)
842 sdev
->queue_depth
= tags
;
844 case MSG_ORDERED_TAG
:
845 sdev
->ordered_tags
= 1;
846 sdev
->simple_tags
= 1;
849 sdev
->ordered_tags
= 0;
850 sdev
->simple_tags
= 1;
853 sdev_printk(KERN_WARNING
, sdev
,
854 "scsi_adjust_queue_depth, bad queue type, "
857 sdev
->ordered_tags
= sdev
->simple_tags
= 0;
858 sdev
->queue_depth
= tags
;
862 spin_unlock_irqrestore(sdev
->request_queue
->queue_lock
, flags
);
864 EXPORT_SYMBOL(scsi_adjust_queue_depth
);
867 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
868 * @sdev: SCSI Device in question
869 * @depth: Current number of outstanding SCSI commands on this device,
870 * not counting the one returned as QUEUE_FULL.
872 * Description: This function will track successive QUEUE_FULL events on a
873 * specific SCSI device to determine if and when there is a
874 * need to adjust the queue depth on the device.
876 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
877 * -1 - Drop back to untagged operation using host->cmd_per_lun
878 * as the untagged command depth
880 * Lock Status: None held on entry
882 * Notes: Low level drivers may call this at any time and we will do
883 * "The Right Thing." We are interrupt context safe.
885 int scsi_track_queue_full(struct scsi_device
*sdev
, int depth
)
889 * Don't let QUEUE_FULLs on the same
890 * jiffies count, they could all be from
893 if ((jiffies
>> 4) == (sdev
->last_queue_full_time
>> 4))
896 sdev
->last_queue_full_time
= jiffies
;
897 if (sdev
->last_queue_full_depth
!= depth
) {
898 sdev
->last_queue_full_count
= 1;
899 sdev
->last_queue_full_depth
= depth
;
901 sdev
->last_queue_full_count
++;
904 if (sdev
->last_queue_full_count
<= 10)
906 if (sdev
->last_queue_full_depth
< 8) {
907 /* Drop back to untagged */
908 scsi_adjust_queue_depth(sdev
, 0, sdev
->host
->cmd_per_lun
);
912 if (sdev
->ordered_tags
)
913 scsi_adjust_queue_depth(sdev
, MSG_ORDERED_TAG
, depth
);
915 scsi_adjust_queue_depth(sdev
, MSG_SIMPLE_TAG
, depth
);
918 EXPORT_SYMBOL(scsi_track_queue_full
);
921 * scsi_vpd_inquiry - Request a device provide us with a VPD page
922 * @sdev: The device to ask
923 * @buffer: Where to put the result
924 * @page: Which Vital Product Data to return
925 * @len: The length of the buffer
927 * This is an internal helper function. You probably want to use
928 * scsi_get_vpd_page instead.
930 * Returns size of the vpd page on success or a negative error number.
932 static int scsi_vpd_inquiry(struct scsi_device
*sdev
, unsigned char *buffer
,
933 u8 page
, unsigned len
)
936 unsigned char cmd
[16];
942 cmd
[1] = 1; /* EVPD */
946 cmd
[5] = 0; /* Control byte */
949 * I'm not convinced we need to try quite this hard to get VPD, but
950 * all the existing users tried this hard.
952 result
= scsi_execute_req(sdev
, cmd
, DMA_FROM_DEVICE
, buffer
,
953 len
, NULL
, 30 * HZ
, 3, NULL
);
957 /* Sanity check that we got the page back that we asked for */
958 if (buffer
[1] != page
)
961 return get_unaligned_be16(&buffer
[2]) + 4;
965 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
966 * @sdev: The device to ask
967 * @page: Which Vital Product Data to return
968 * @buf: where to store the VPD
969 * @buf_len: number of bytes in the VPD buffer area
971 * SCSI devices may optionally supply Vital Product Data. Each 'page'
972 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
973 * If the device supports this VPD page, this routine returns a pointer
974 * to a buffer containing the data from that page. The caller is
975 * responsible for calling kfree() on this pointer when it is no longer
976 * needed. If we cannot retrieve the VPD page this routine returns %NULL.
978 int scsi_get_vpd_page(struct scsi_device
*sdev
, u8 page
, unsigned char *buf
,
983 if (sdev
->skip_vpd_pages
)
986 /* Ask for all the pages supported by this device */
987 result
= scsi_vpd_inquiry(sdev
, buf
, 0, buf_len
);
991 /* If the user actually wanted this page, we can skip the rest */
995 for (i
= 4; i
< min(result
, buf_len
); i
++)
999 if (i
< result
&& i
>= buf_len
)
1000 /* ran off the end of the buffer, give us benefit of doubt */
1002 /* The device claims it doesn't support the requested page */
1006 result
= scsi_vpd_inquiry(sdev
, buf
, page
, buf_len
);
1015 EXPORT_SYMBOL_GPL(scsi_get_vpd_page
);
1018 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure
1019 * @sdev: The device to ask
1021 * Attach the 'Device Identification' VPD page (0x83) and the
1022 * 'Unit Serial Number' VPD page (0x80) to a SCSI device
1023 * structure. This information can be used to identify the device
1026 void scsi_attach_vpd(struct scsi_device
*sdev
)
1029 int vpd_len
= SCSI_VPD_PG_LEN
;
1030 int pg80_supported
= 0;
1031 int pg83_supported
= 0;
1032 unsigned char *vpd_buf
;
1034 if (sdev
->skip_vpd_pages
)
1037 vpd_buf
= kmalloc(vpd_len
, GFP_KERNEL
);
1041 /* Ask for all the pages supported by this device */
1042 result
= scsi_vpd_inquiry(sdev
, vpd_buf
, 0, vpd_len
);
1047 if (result
> vpd_len
) {
1053 for (i
= 4; i
< result
; i
++) {
1054 if (vpd_buf
[i
] == 0x80)
1056 if (vpd_buf
[i
] == 0x83)
1060 vpd_len
= SCSI_VPD_PG_LEN
;
1062 if (pg80_supported
) {
1064 vpd_buf
= kmalloc(vpd_len
, GFP_KERNEL
);
1068 result
= scsi_vpd_inquiry(sdev
, vpd_buf
, 0x80, vpd_len
);
1073 if (result
> vpd_len
) {
1078 sdev
->vpd_pg80_len
= result
;
1079 sdev
->vpd_pg80
= vpd_buf
;
1080 vpd_len
= SCSI_VPD_PG_LEN
;
1083 if (pg83_supported
) {
1085 vpd_buf
= kmalloc(vpd_len
, GFP_KERNEL
);
1089 result
= scsi_vpd_inquiry(sdev
, vpd_buf
, 0x83, vpd_len
);
1094 if (result
> vpd_len
) {
1099 sdev
->vpd_pg83_len
= result
;
1100 sdev
->vpd_pg83
= vpd_buf
;
1105 * scsi_report_opcode - Find out if a given command opcode is supported
1106 * @sdev: scsi device to query
1107 * @buffer: scratch buffer (must be at least 20 bytes long)
1108 * @len: length of buffer
1109 * @opcode: opcode for command to look up
1111 * Uses the REPORT SUPPORTED OPERATION CODES to look up the given
1112 * opcode. Returns -EINVAL if RSOC fails, 0 if the command opcode is
1113 * unsupported and 1 if the device claims to support the command.
1115 int scsi_report_opcode(struct scsi_device
*sdev
, unsigned char *buffer
,
1116 unsigned int len
, unsigned char opcode
)
1118 unsigned char cmd
[16];
1119 struct scsi_sense_hdr sshdr
;
1122 if (sdev
->no_report_opcodes
|| sdev
->scsi_level
< SCSI_SPC_3
)
1126 cmd
[0] = MAINTENANCE_IN
;
1127 cmd
[1] = MI_REPORT_SUPPORTED_OPERATION_CODES
;
1128 cmd
[2] = 1; /* One command format */
1130 put_unaligned_be32(len
, &cmd
[6]);
1131 memset(buffer
, 0, len
);
1133 result
= scsi_execute_req(sdev
, cmd
, DMA_FROM_DEVICE
, buffer
, len
,
1134 &sshdr
, 30 * HZ
, 3, NULL
);
1136 if (result
&& scsi_sense_valid(&sshdr
) &&
1137 sshdr
.sense_key
== ILLEGAL_REQUEST
&&
1138 (sshdr
.asc
== 0x20 || sshdr
.asc
== 0x24) && sshdr
.ascq
== 0x00)
1141 if ((buffer
[1] & 3) == 3) /* Command supported */
1146 EXPORT_SYMBOL(scsi_report_opcode
);
1149 * scsi_device_get - get an additional reference to a scsi_device
1150 * @sdev: device to get a reference to
1152 * Description: Gets a reference to the scsi_device and increments the use count
1153 * of the underlying LLDD module. You must hold host_lock of the
1154 * parent Scsi_Host or already have a reference when calling this.
1156 int scsi_device_get(struct scsi_device
*sdev
)
1158 if (sdev
->sdev_state
== SDEV_DEL
)
1160 if (!get_device(&sdev
->sdev_gendev
))
1162 /* We can fail this if we're doing SCSI operations
1163 * from module exit (like cache flush) */
1164 try_module_get(sdev
->host
->hostt
->module
);
1168 EXPORT_SYMBOL(scsi_device_get
);
1171 * scsi_device_put - release a reference to a scsi_device
1172 * @sdev: device to release a reference on.
1174 * Description: Release a reference to the scsi_device and decrements the use
1175 * count of the underlying LLDD module. The device is freed once the last
1178 void scsi_device_put(struct scsi_device
*sdev
)
1180 #ifdef CONFIG_MODULE_UNLOAD
1181 struct module
*module
= sdev
->host
->hostt
->module
;
1183 /* The module refcount will be zero if scsi_device_get()
1184 * was called from a module removal routine */
1185 if (module
&& module_refcount(module
) != 0)
1188 put_device(&sdev
->sdev_gendev
);
1190 EXPORT_SYMBOL(scsi_device_put
);
1192 /* helper for shost_for_each_device, see that for documentation */
1193 struct scsi_device
*__scsi_iterate_devices(struct Scsi_Host
*shost
,
1194 struct scsi_device
*prev
)
1196 struct list_head
*list
= (prev
? &prev
->siblings
: &shost
->__devices
);
1197 struct scsi_device
*next
= NULL
;
1198 unsigned long flags
;
1200 spin_lock_irqsave(shost
->host_lock
, flags
);
1201 while (list
->next
!= &shost
->__devices
) {
1202 next
= list_entry(list
->next
, struct scsi_device
, siblings
);
1203 /* skip devices that we can't get a reference to */
1204 if (!scsi_device_get(next
))
1209 spin_unlock_irqrestore(shost
->host_lock
, flags
);
1212 scsi_device_put(prev
);
1215 EXPORT_SYMBOL(__scsi_iterate_devices
);
1218 * starget_for_each_device - helper to walk all devices of a target
1219 * @starget: target whose devices we want to iterate over.
1220 * @data: Opaque passed to each function call.
1221 * @fn: Function to call on each device
1223 * This traverses over each device of @starget. The devices have
1224 * a reference that must be released by scsi_host_put when breaking
1227 void starget_for_each_device(struct scsi_target
*starget
, void *data
,
1228 void (*fn
)(struct scsi_device
*, void *))
1230 struct Scsi_Host
*shost
= dev_to_shost(starget
->dev
.parent
);
1231 struct scsi_device
*sdev
;
1233 shost_for_each_device(sdev
, shost
) {
1234 if ((sdev
->channel
== starget
->channel
) &&
1235 (sdev
->id
== starget
->id
))
1239 EXPORT_SYMBOL(starget_for_each_device
);
1242 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
1243 * @starget: target whose devices we want to iterate over.
1244 * @data: parameter for callback @fn()
1245 * @fn: callback function that is invoked for each device
1247 * This traverses over each device of @starget. It does _not_
1248 * take a reference on the scsi_device, so the whole loop must be
1249 * protected by shost->host_lock.
1251 * Note: The only reason why drivers would want to use this is because
1252 * they need to access the device list in irq context. Otherwise you
1253 * really want to use starget_for_each_device instead.
1255 void __starget_for_each_device(struct scsi_target
*starget
, void *data
,
1256 void (*fn
)(struct scsi_device
*, void *))
1258 struct Scsi_Host
*shost
= dev_to_shost(starget
->dev
.parent
);
1259 struct scsi_device
*sdev
;
1261 __shost_for_each_device(sdev
, shost
) {
1262 if ((sdev
->channel
== starget
->channel
) &&
1263 (sdev
->id
== starget
->id
))
1267 EXPORT_SYMBOL(__starget_for_each_device
);
1270 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
1271 * @starget: SCSI target pointer
1272 * @lun: SCSI Logical Unit Number
1274 * Description: Looks up the scsi_device with the specified @lun for a given
1275 * @starget. The returned scsi_device does not have an additional
1276 * reference. You must hold the host's host_lock over this call and
1277 * any access to the returned scsi_device. A scsi_device in state
1278 * SDEV_DEL is skipped.
1280 * Note: The only reason why drivers should use this is because
1281 * they need to access the device list in irq context. Otherwise you
1282 * really want to use scsi_device_lookup_by_target instead.
1284 struct scsi_device
*__scsi_device_lookup_by_target(struct scsi_target
*starget
,
1287 struct scsi_device
*sdev
;
1289 list_for_each_entry(sdev
, &starget
->devices
, same_target_siblings
) {
1290 if (sdev
->sdev_state
== SDEV_DEL
)
1292 if (sdev
->lun
==lun
)
1298 EXPORT_SYMBOL(__scsi_device_lookup_by_target
);
1301 * scsi_device_lookup_by_target - find a device given the target
1302 * @starget: SCSI target pointer
1303 * @lun: SCSI Logical Unit Number
1305 * Description: Looks up the scsi_device with the specified @lun for a given
1306 * @starget. The returned scsi_device has an additional reference that
1307 * needs to be released with scsi_device_put once you're done with it.
1309 struct scsi_device
*scsi_device_lookup_by_target(struct scsi_target
*starget
,
1312 struct scsi_device
*sdev
;
1313 struct Scsi_Host
*shost
= dev_to_shost(starget
->dev
.parent
);
1314 unsigned long flags
;
1316 spin_lock_irqsave(shost
->host_lock
, flags
);
1317 sdev
= __scsi_device_lookup_by_target(starget
, lun
);
1318 if (sdev
&& scsi_device_get(sdev
))
1320 spin_unlock_irqrestore(shost
->host_lock
, flags
);
1324 EXPORT_SYMBOL(scsi_device_lookup_by_target
);
1327 * __scsi_device_lookup - find a device given the host (UNLOCKED)
1328 * @shost: SCSI host pointer
1329 * @channel: SCSI channel (zero if only one channel)
1330 * @id: SCSI target number (physical unit number)
1331 * @lun: SCSI Logical Unit Number
1333 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1334 * for a given host. The returned scsi_device does not have an additional
1335 * reference. You must hold the host's host_lock over this call and any access
1336 * to the returned scsi_device.
1338 * Note: The only reason why drivers would want to use this is because
1339 * they need to access the device list in irq context. Otherwise you
1340 * really want to use scsi_device_lookup instead.
1342 struct scsi_device
*__scsi_device_lookup(struct Scsi_Host
*shost
,
1343 uint channel
, uint id
, uint lun
)
1345 struct scsi_device
*sdev
;
1347 list_for_each_entry(sdev
, &shost
->__devices
, siblings
) {
1348 if (sdev
->channel
== channel
&& sdev
->id
== id
&&
1355 EXPORT_SYMBOL(__scsi_device_lookup
);
1358 * scsi_device_lookup - find a device given the host
1359 * @shost: SCSI host pointer
1360 * @channel: SCSI channel (zero if only one channel)
1361 * @id: SCSI target number (physical unit number)
1362 * @lun: SCSI Logical Unit Number
1364 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1365 * for a given host. The returned scsi_device has an additional reference that
1366 * needs to be released with scsi_device_put once you're done with it.
1368 struct scsi_device
*scsi_device_lookup(struct Scsi_Host
*shost
,
1369 uint channel
, uint id
, uint lun
)
1371 struct scsi_device
*sdev
;
1372 unsigned long flags
;
1374 spin_lock_irqsave(shost
->host_lock
, flags
);
1375 sdev
= __scsi_device_lookup(shost
, channel
, id
, lun
);
1376 if (sdev
&& scsi_device_get(sdev
))
1378 spin_unlock_irqrestore(shost
->host_lock
, flags
);
1382 EXPORT_SYMBOL(scsi_device_lookup
);
1384 MODULE_DESCRIPTION("SCSI core");
1385 MODULE_LICENSE("GPL");
1387 module_param(scsi_logging_level
, int, S_IRUGO
|S_IWUSR
);
1388 MODULE_PARM_DESC(scsi_logging_level
, "a bit mask of logging levels");
1390 static int __init
init_scsi(void)
1394 error
= scsi_init_queue();
1397 error
= scsi_init_procfs();
1400 error
= scsi_init_devinfo();
1402 goto cleanup_procfs
;
1403 error
= scsi_init_hosts();
1405 goto cleanup_devlist
;
1406 error
= scsi_init_sysctl();
1409 error
= scsi_sysfs_register();
1411 goto cleanup_sysctl
;
1413 scsi_netlink_init();
1415 printk(KERN_NOTICE
"SCSI subsystem initialized\n");
1423 scsi_exit_devinfo();
1428 printk(KERN_ERR
"SCSI subsystem failed to initialize, error = %d\n",
1433 static void __exit
exit_scsi(void)
1435 scsi_netlink_exit();
1436 scsi_sysfs_unregister();
1439 scsi_exit_devinfo();
1442 async_unregister_domain(&scsi_sd_probe_domain
);
1445 subsys_initcall(init_scsi
);
1446 module_exit(exit_scsi
);