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.
81 #define MIN_RESET_DELAY (2*HZ)
83 /* Do not call reset on error if we just did a reset within 15 sec. */
84 #define MIN_RESET_PERIOD (15*HZ)
87 * Note - the initial logging level can be set here to log events at boot time.
88 * After the system is up, you may enable logging via the /proc interface.
90 unsigned int scsi_logging_level
;
91 #if defined(CONFIG_SCSI_LOGGING)
92 EXPORT_SYMBOL(scsi_logging_level
);
95 /* sd, scsi core and power management need to coordinate flushing async actions */
96 ASYNC_DOMAIN(scsi_sd_probe_domain
);
97 EXPORT_SYMBOL(scsi_sd_probe_domain
);
99 /* NB: These are exposed through /proc/scsi/scsi and form part of the ABI.
100 * You may not alter any existing entry (although adding new ones is
101 * encouraged once assigned by ANSI/INCITS T10
103 static const char *const scsi_device_types
[] = {
126 * scsi_device_type - Return 17 char string indicating device type.
127 * @type: type number to look up
130 const char * scsi_device_type(unsigned type
)
133 return "Well-known LUN ";
136 if (type
>= ARRAY_SIZE(scsi_device_types
))
138 return scsi_device_types
[type
];
141 EXPORT_SYMBOL(scsi_device_type
);
143 struct scsi_host_cmd_pool
{
144 struct kmem_cache
*cmd_slab
;
145 struct kmem_cache
*sense_slab
;
149 unsigned int slab_flags
;
153 static struct scsi_host_cmd_pool scsi_cmd_pool
= {
154 .cmd_name
= "scsi_cmd_cache",
155 .sense_name
= "scsi_sense_cache",
156 .slab_flags
= SLAB_HWCACHE_ALIGN
,
159 static struct scsi_host_cmd_pool scsi_cmd_dma_pool
= {
160 .cmd_name
= "scsi_cmd_cache(DMA)",
161 .sense_name
= "scsi_sense_cache(DMA)",
162 .slab_flags
= SLAB_HWCACHE_ALIGN
|SLAB_CACHE_DMA
,
163 .gfp_mask
= __GFP_DMA
,
166 static DEFINE_MUTEX(host_cmd_pool_mutex
);
169 * scsi_pool_alloc_command - internal function to get a fully allocated command
170 * @pool: slab pool to allocate the command from
171 * @gfp_mask: mask for the allocation
173 * Returns a fully allocated command (with the allied sense buffer) or
176 static struct scsi_cmnd
*
177 scsi_pool_alloc_command(struct scsi_host_cmd_pool
*pool
, gfp_t gfp_mask
)
179 struct scsi_cmnd
*cmd
;
181 cmd
= kmem_cache_zalloc(pool
->cmd_slab
, gfp_mask
| pool
->gfp_mask
);
185 cmd
->sense_buffer
= kmem_cache_alloc(pool
->sense_slab
,
186 gfp_mask
| pool
->gfp_mask
);
187 if (!cmd
->sense_buffer
) {
188 kmem_cache_free(pool
->cmd_slab
, cmd
);
196 * scsi_pool_free_command - internal function to release a command
197 * @pool: slab pool to allocate the command from
198 * @cmd: command to release
200 * the command must previously have been allocated by
201 * scsi_pool_alloc_command.
204 scsi_pool_free_command(struct scsi_host_cmd_pool
*pool
,
205 struct scsi_cmnd
*cmd
)
208 kmem_cache_free(scsi_sdb_cache
, cmd
->prot_sdb
);
210 kmem_cache_free(pool
->sense_slab
, cmd
->sense_buffer
);
211 kmem_cache_free(pool
->cmd_slab
, cmd
);
215 * scsi_host_alloc_command - internal function to allocate command
216 * @shost: SCSI host whose pool to allocate from
217 * @gfp_mask: mask for the allocation
219 * Returns a fully allocated command with sense buffer and protection
220 * data buffer (where applicable) or NULL on failure
222 static struct scsi_cmnd
*
223 scsi_host_alloc_command(struct Scsi_Host
*shost
, gfp_t gfp_mask
)
225 struct scsi_cmnd
*cmd
;
227 cmd
= scsi_pool_alloc_command(shost
->cmd_pool
, gfp_mask
);
231 if (scsi_host_get_prot(shost
) >= SHOST_DIX_TYPE0_PROTECTION
) {
232 cmd
->prot_sdb
= kmem_cache_zalloc(scsi_sdb_cache
, gfp_mask
);
234 if (!cmd
->prot_sdb
) {
235 scsi_pool_free_command(shost
->cmd_pool
, cmd
);
244 * __scsi_get_command - Allocate a struct scsi_cmnd
245 * @shost: host to transmit command
246 * @gfp_mask: allocation mask
248 * Description: allocate a struct scsi_cmd from host's slab, recycling from the
249 * host's free_list if necessary.
251 struct scsi_cmnd
*__scsi_get_command(struct Scsi_Host
*shost
, gfp_t gfp_mask
)
253 struct scsi_cmnd
*cmd
= scsi_host_alloc_command(shost
, gfp_mask
);
255 if (unlikely(!cmd
)) {
258 spin_lock_irqsave(&shost
->free_list_lock
, flags
);
259 if (likely(!list_empty(&shost
->free_list
))) {
260 cmd
= list_entry(shost
->free_list
.next
,
261 struct scsi_cmnd
, list
);
262 list_del_init(&cmd
->list
);
264 spin_unlock_irqrestore(&shost
->free_list_lock
, flags
);
269 buf
= cmd
->sense_buffer
;
270 prot
= cmd
->prot_sdb
;
272 memset(cmd
, 0, sizeof(*cmd
));
274 cmd
->sense_buffer
= buf
;
275 cmd
->prot_sdb
= prot
;
281 EXPORT_SYMBOL_GPL(__scsi_get_command
);
284 * scsi_get_command - Allocate and setup a scsi command block
285 * @dev: parent scsi device
286 * @gfp_mask: allocator flags
288 * Returns: The allocated scsi command structure.
290 struct scsi_cmnd
*scsi_get_command(struct scsi_device
*dev
, gfp_t gfp_mask
)
292 struct scsi_cmnd
*cmd
;
294 /* Bail if we can't get a reference to the device */
295 if (!get_device(&dev
->sdev_gendev
))
298 cmd
= __scsi_get_command(dev
->host
, gfp_mask
);
300 if (likely(cmd
!= NULL
)) {
304 INIT_LIST_HEAD(&cmd
->list
);
305 spin_lock_irqsave(&dev
->list_lock
, flags
);
306 list_add_tail(&cmd
->list
, &dev
->cmd_list
);
307 spin_unlock_irqrestore(&dev
->list_lock
, flags
);
308 cmd
->jiffies_at_alloc
= jiffies
;
310 put_device(&dev
->sdev_gendev
);
314 EXPORT_SYMBOL(scsi_get_command
);
317 * __scsi_put_command - Free a struct scsi_cmnd
319 * @cmd: Command to free
320 * @dev: parent scsi device
322 void __scsi_put_command(struct Scsi_Host
*shost
, struct scsi_cmnd
*cmd
,
327 /* changing locks here, don't need to restore the irq state */
328 spin_lock_irqsave(&shost
->free_list_lock
, flags
);
329 if (unlikely(list_empty(&shost
->free_list
))) {
330 list_add(&cmd
->list
, &shost
->free_list
);
333 spin_unlock_irqrestore(&shost
->free_list_lock
, flags
);
335 if (likely(cmd
!= NULL
))
336 scsi_pool_free_command(shost
->cmd_pool
, cmd
);
340 EXPORT_SYMBOL(__scsi_put_command
);
343 * scsi_put_command - Free a scsi command block
344 * @cmd: command block to free
348 * Notes: The command must not belong to any lists.
350 void scsi_put_command(struct scsi_cmnd
*cmd
)
352 struct scsi_device
*sdev
= cmd
->device
;
355 /* serious error if the command hasn't come from a device list */
356 spin_lock_irqsave(&cmd
->device
->list_lock
, flags
);
357 BUG_ON(list_empty(&cmd
->list
));
358 list_del_init(&cmd
->list
);
359 spin_unlock_irqrestore(&cmd
->device
->list_lock
, flags
);
361 __scsi_put_command(cmd
->device
->host
, cmd
, &sdev
->sdev_gendev
);
363 EXPORT_SYMBOL(scsi_put_command
);
365 static struct scsi_host_cmd_pool
*scsi_get_host_cmd_pool(gfp_t gfp_mask
)
367 struct scsi_host_cmd_pool
*retval
= NULL
, *pool
;
369 * Select a command slab for this host and create it if not
372 mutex_lock(&host_cmd_pool_mutex
);
373 pool
= (gfp_mask
& __GFP_DMA
) ? &scsi_cmd_dma_pool
:
376 pool
->cmd_slab
= kmem_cache_create(pool
->cmd_name
,
377 sizeof(struct scsi_cmnd
), 0,
378 pool
->slab_flags
, NULL
);
382 pool
->sense_slab
= kmem_cache_create(pool
->sense_name
,
383 SCSI_SENSE_BUFFERSIZE
, 0,
384 pool
->slab_flags
, NULL
);
385 if (!pool
->sense_slab
) {
386 kmem_cache_destroy(pool
->cmd_slab
);
394 mutex_unlock(&host_cmd_pool_mutex
);
398 static void scsi_put_host_cmd_pool(gfp_t gfp_mask
)
400 struct scsi_host_cmd_pool
*pool
;
402 mutex_lock(&host_cmd_pool_mutex
);
403 pool
= (gfp_mask
& __GFP_DMA
) ? &scsi_cmd_dma_pool
:
406 * This may happen if a driver has a mismatched get and put
407 * of the command pool; the driver should be implicated in
410 BUG_ON(pool
->users
== 0);
412 if (!--pool
->users
) {
413 kmem_cache_destroy(pool
->cmd_slab
);
414 kmem_cache_destroy(pool
->sense_slab
);
416 mutex_unlock(&host_cmd_pool_mutex
);
420 * scsi_allocate_command - get a fully allocated SCSI command
421 * @gfp_mask: allocation mask
423 * This function is for use outside of the normal host based pools.
424 * It allocates the relevant command and takes an additional reference
425 * on the pool it used. This function *must* be paired with
426 * scsi_free_command which also has the identical mask, otherwise the
427 * free pool counts will eventually go wrong and you'll trigger a bug.
429 * This function should *only* be used by drivers that need a static
430 * command allocation at start of day for internal functions.
432 struct scsi_cmnd
*scsi_allocate_command(gfp_t gfp_mask
)
434 struct scsi_host_cmd_pool
*pool
= scsi_get_host_cmd_pool(gfp_mask
);
439 return scsi_pool_alloc_command(pool
, gfp_mask
);
441 EXPORT_SYMBOL(scsi_allocate_command
);
444 * scsi_free_command - free a command allocated by scsi_allocate_command
445 * @gfp_mask: mask used in the original allocation
446 * @cmd: command to free
448 * Note: using the original allocation mask is vital because that's
449 * what determines which command pool we use to free the command. Any
450 * mismatch will cause the system to BUG eventually.
452 void scsi_free_command(gfp_t gfp_mask
, struct scsi_cmnd
*cmd
)
454 struct scsi_host_cmd_pool
*pool
= scsi_get_host_cmd_pool(gfp_mask
);
457 * this could trigger if the mask to scsi_allocate_command
458 * doesn't match this mask. Otherwise we're guaranteed that this
459 * succeeds because scsi_allocate_command must have taken a reference
464 scsi_pool_free_command(pool
, cmd
);
466 * scsi_put_host_cmd_pool is called twice; once to release the
467 * reference we took above, and once to release the reference
468 * originally taken by scsi_allocate_command
470 scsi_put_host_cmd_pool(gfp_mask
);
471 scsi_put_host_cmd_pool(gfp_mask
);
473 EXPORT_SYMBOL(scsi_free_command
);
476 * scsi_setup_command_freelist - Setup the command freelist for a scsi host.
477 * @shost: host to allocate the freelist for.
479 * Description: The command freelist protects against system-wide out of memory
480 * deadlock by preallocating one SCSI command structure for each host, so the
481 * system can always write to a swap file on a device associated with that host.
485 int scsi_setup_command_freelist(struct Scsi_Host
*shost
)
487 struct scsi_cmnd
*cmd
;
488 const gfp_t gfp_mask
= shost
->unchecked_isa_dma
? GFP_DMA
: GFP_KERNEL
;
490 spin_lock_init(&shost
->free_list_lock
);
491 INIT_LIST_HEAD(&shost
->free_list
);
493 shost
->cmd_pool
= scsi_get_host_cmd_pool(gfp_mask
);
495 if (!shost
->cmd_pool
)
499 * Get one backup command for this host.
501 cmd
= scsi_host_alloc_command(shost
, gfp_mask
);
503 scsi_put_host_cmd_pool(gfp_mask
);
504 shost
->cmd_pool
= NULL
;
507 list_add(&cmd
->list
, &shost
->free_list
);
512 * scsi_destroy_command_freelist - Release the command freelist for a scsi host.
513 * @shost: host whose freelist is going to be destroyed
515 void scsi_destroy_command_freelist(struct Scsi_Host
*shost
)
518 * If cmd_pool is NULL the free list was not initialized, so
519 * do not attempt to release resources.
521 if (!shost
->cmd_pool
)
524 while (!list_empty(&shost
->free_list
)) {
525 struct scsi_cmnd
*cmd
;
527 cmd
= list_entry(shost
->free_list
.next
, struct scsi_cmnd
, list
);
528 list_del_init(&cmd
->list
);
529 scsi_pool_free_command(shost
->cmd_pool
, cmd
);
531 shost
->cmd_pool
= NULL
;
532 scsi_put_host_cmd_pool(shost
->unchecked_isa_dma
? GFP_DMA
: GFP_KERNEL
);
535 #ifdef CONFIG_SCSI_LOGGING
536 void scsi_log_send(struct scsi_cmnd
*cmd
)
541 * If ML QUEUE log level is greater than or equal to:
543 * 1: nothing (match completion)
545 * 2: log opcode + command of all commands
547 * 3: same as 2 plus dump cmd address
549 * 4: same as 3 plus dump extra junk
551 if (unlikely(scsi_logging_level
)) {
552 level
= SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT
,
553 SCSI_LOG_MLQUEUE_BITS
);
555 scmd_printk(KERN_INFO
, cmd
, "Send: ");
557 printk("0x%p ", cmd
);
559 scsi_print_command(cmd
);
561 printk(KERN_INFO
"buffer = 0x%p, bufflen = %d,"
562 " queuecommand 0x%p\n",
563 scsi_sglist(cmd
), scsi_bufflen(cmd
),
564 cmd
->device
->host
->hostt
->queuecommand
);
571 void scsi_log_completion(struct scsi_cmnd
*cmd
, int disposition
)
576 * If ML COMPLETE log level is greater than or equal to:
578 * 1: log disposition, result, opcode + command, and conditionally
579 * sense data for failures or non SUCCESS dispositions.
581 * 2: same as 1 but for all command completions.
583 * 3: same as 2 plus dump cmd address
585 * 4: same as 3 plus dump extra junk
587 if (unlikely(scsi_logging_level
)) {
588 level
= SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT
,
589 SCSI_LOG_MLCOMPLETE_BITS
);
590 if (((level
> 0) && (cmd
->result
|| disposition
!= SUCCESS
)) ||
592 scmd_printk(KERN_INFO
, cmd
, "Done: ");
594 printk("0x%p ", cmd
);
596 * Dump truncated values, so we usually fit within
599 switch (disposition
) {
614 * If called via scsi_times_out.
621 scsi_print_result(cmd
);
622 scsi_print_command(cmd
);
623 if (status_byte(cmd
->result
) & CHECK_CONDITION
)
624 scsi_print_sense("", cmd
);
626 scmd_printk(KERN_INFO
, cmd
,
627 "scsi host busy %d failed %d\n",
628 cmd
->device
->host
->host_busy
,
629 cmd
->device
->host
->host_failed
);
636 * scsi_cmd_get_serial - Assign a serial number to a command
637 * @host: the scsi host
638 * @cmd: command to assign serial number to
640 * Description: a serial number identifies a request for error recovery
641 * and debugging purposes. Protected by the Host_Lock of host.
643 void scsi_cmd_get_serial(struct Scsi_Host
*host
, struct scsi_cmnd
*cmd
)
645 cmd
->serial_number
= host
->cmd_serial_number
++;
646 if (cmd
->serial_number
== 0)
647 cmd
->serial_number
= host
->cmd_serial_number
++;
649 EXPORT_SYMBOL(scsi_cmd_get_serial
);
652 * scsi_dispatch_command - Dispatch a command to the low-level driver.
653 * @cmd: command block we are dispatching.
655 * Return: nonzero return request was rejected and device's queue needs to be
658 int scsi_dispatch_cmd(struct scsi_cmnd
*cmd
)
660 struct Scsi_Host
*host
= cmd
->device
->host
;
661 unsigned long timeout
;
664 atomic_inc(&cmd
->device
->iorequest_cnt
);
666 /* check if the device is still usable */
667 if (unlikely(cmd
->device
->sdev_state
== SDEV_DEL
)) {
668 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
669 * returns an immediate error upwards, and signals
670 * that the device is no longer present */
671 cmd
->result
= DID_NO_CONNECT
<< 16;
673 /* return 0 (because the command has been processed) */
677 /* Check to see if the scsi lld made this device blocked. */
678 if (unlikely(scsi_device_blocked(cmd
->device
))) {
680 * in blocked state, the command is just put back on
681 * the device queue. The suspend state has already
682 * blocked the queue so future requests should not
683 * occur until the device transitions out of the
687 scsi_queue_insert(cmd
, SCSI_MLQUEUE_DEVICE_BUSY
);
689 SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
692 * NOTE: rtn is still zero here because we don't need the
693 * queue to be plugged on return (it's already stopped)
699 * If SCSI-2 or lower, store the LUN value in cmnd.
701 if (cmd
->device
->scsi_level
<= SCSI_2
&&
702 cmd
->device
->scsi_level
!= SCSI_UNKNOWN
) {
703 cmd
->cmnd
[1] = (cmd
->cmnd
[1] & 0x1f) |
704 (cmd
->device
->lun
<< 5 & 0xe0);
708 * We will wait MIN_RESET_DELAY clock ticks after the last reset so
709 * we can avoid the drive not being ready.
711 timeout
= host
->last_reset
+ MIN_RESET_DELAY
;
713 if (host
->resetting
&& time_before(jiffies
, timeout
)) {
714 int ticks_remaining
= timeout
- jiffies
;
716 * NOTE: This may be executed from within an interrupt
717 * handler! This is bad, but for now, it'll do. The irq
718 * level of the interrupt handler has been masked out by the
719 * platform dependent interrupt handling code already, so the
720 * sti() here will not cause another call to the SCSI host's
721 * interrupt handler (assuming there is one irq-level per
724 while (--ticks_remaining
>= 0)
725 mdelay(1 + 999 / HZ
);
732 * Before we queue this command, check if the command
733 * length exceeds what the host adapter can handle.
735 if (cmd
->cmd_len
> cmd
->device
->host
->max_cmd_len
) {
737 printk("queuecommand : command too long. "
738 "cdb_size=%d host->max_cmd_len=%d\n",
739 cmd
->cmd_len
, cmd
->device
->host
->max_cmd_len
));
740 cmd
->result
= (DID_ABORT
<< 16);
746 if (unlikely(host
->shost_state
== SHOST_DEL
)) {
747 cmd
->result
= (DID_NO_CONNECT
<< 16);
750 trace_scsi_dispatch_cmd_start(cmd
);
751 cmd
->scsi_done
= scsi_done
;
752 rtn
= host
->hostt
->queuecommand(host
, cmd
);
756 trace_scsi_dispatch_cmd_error(cmd
, rtn
);
757 if (rtn
!= SCSI_MLQUEUE_DEVICE_BUSY
&&
758 rtn
!= SCSI_MLQUEUE_TARGET_BUSY
)
759 rtn
= SCSI_MLQUEUE_HOST_BUSY
;
761 scsi_queue_insert(cmd
, rtn
);
764 printk("queuecommand : request rejected\n"));
768 SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
773 * scsi_done - Enqueue the finished SCSI command into the done queue.
774 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
775 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
777 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
778 * which regains ownership of the SCSI command (de facto) from a LLDD, and
779 * enqueues the command to the done queue for further processing.
781 * This is the producer of the done queue who enqueues at the tail.
783 * This function is interrupt context safe.
785 static void scsi_done(struct scsi_cmnd
*cmd
)
787 trace_scsi_dispatch_cmd_done(cmd
);
788 blk_complete_request(cmd
->request
);
792 * scsi_finish_command - cleanup and pass command back to upper layer
795 * Description: Pass command off to upper layer for finishing of I/O
796 * request, waking processes that are waiting on results,
799 void scsi_finish_command(struct scsi_cmnd
*cmd
)
801 struct scsi_device
*sdev
= cmd
->device
;
802 struct scsi_target
*starget
= scsi_target(sdev
);
803 struct Scsi_Host
*shost
= sdev
->host
;
804 struct scsi_driver
*drv
;
805 unsigned int good_bytes
;
807 scsi_device_unbusy(sdev
);
810 * Clear the flags which say that the device/host is no longer
811 * capable of accepting new commands. These are set in scsi_queue.c
812 * for both the queue full condition on a device, and for a
813 * host full condition on the host.
815 * XXX(hch): What about locking?
817 shost
->host_blocked
= 0;
818 starget
->target_blocked
= 0;
819 sdev
->device_blocked
= 0;
822 * If we have valid sense information, then some kind of recovery
823 * must have taken place. Make a note of this.
825 if (SCSI_SENSE_VALID(cmd
))
826 cmd
->result
|= (DRIVER_SENSE
<< 24);
828 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO
, sdev
,
829 "Notifying upper driver of completion "
830 "(result %x)\n", cmd
->result
));
832 good_bytes
= scsi_bufflen(cmd
);
833 if (cmd
->request
->cmd_type
!= REQ_TYPE_BLOCK_PC
) {
834 int old_good_bytes
= good_bytes
;
835 drv
= scsi_cmd_to_driver(cmd
);
837 good_bytes
= drv
->done(cmd
);
839 * USB may not give sense identifying bad sector and
840 * simply return a residue instead, so subtract off the
841 * residue if drv->done() error processing indicates no
842 * change to the completion length.
844 if (good_bytes
== old_good_bytes
)
845 good_bytes
-= scsi_get_resid(cmd
);
847 scsi_io_completion(cmd
, good_bytes
);
849 EXPORT_SYMBOL(scsi_finish_command
);
852 * scsi_adjust_queue_depth - Let low level drivers change a device's queue depth
853 * @sdev: SCSI Device in question
854 * @tagged: Do we use tagged queueing (non-0) or do we treat
855 * this device as an untagged device (0)
856 * @tags: Number of tags allowed if tagged queueing enabled,
857 * or number of commands the low level driver can
858 * queue up in non-tagged mode (as per cmd_per_lun).
862 * Lock Status: None held on entry
864 * Notes: Low level drivers may call this at any time and we will do
865 * the right thing depending on whether or not the device is
866 * currently active and whether or not it even has the
867 * command blocks built yet.
869 void scsi_adjust_queue_depth(struct scsi_device
*sdev
, int tagged
, int tags
)
874 * refuse to set tagged depth to an unworkable size
879 spin_lock_irqsave(sdev
->request_queue
->queue_lock
, flags
);
882 * Check to see if the queue is managed by the block layer.
883 * If it is, and we fail to adjust the depth, exit.
885 * Do not resize the tag map if it is a host wide share bqt,
886 * because the size should be the hosts's can_queue. If there
887 * is more IO than the LLD's can_queue (so there are not enuogh
888 * tags) request_fn's host queue ready check will handle it.
890 if (!sdev
->host
->bqt
) {
891 if (blk_queue_tagged(sdev
->request_queue
) &&
892 blk_queue_resize_tags(sdev
->request_queue
, tags
) != 0)
896 sdev
->queue_depth
= tags
;
898 case MSG_ORDERED_TAG
:
899 sdev
->ordered_tags
= 1;
900 sdev
->simple_tags
= 1;
903 sdev
->ordered_tags
= 0;
904 sdev
->simple_tags
= 1;
907 sdev_printk(KERN_WARNING
, sdev
,
908 "scsi_adjust_queue_depth, bad queue type, "
911 sdev
->ordered_tags
= sdev
->simple_tags
= 0;
912 sdev
->queue_depth
= tags
;
916 spin_unlock_irqrestore(sdev
->request_queue
->queue_lock
, flags
);
918 EXPORT_SYMBOL(scsi_adjust_queue_depth
);
921 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
922 * @sdev: SCSI Device in question
923 * @depth: Current number of outstanding SCSI commands on this device,
924 * not counting the one returned as QUEUE_FULL.
926 * Description: This function will track successive QUEUE_FULL events on a
927 * specific SCSI device to determine if and when there is a
928 * need to adjust the queue depth on the device.
930 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
931 * -1 - Drop back to untagged operation using host->cmd_per_lun
932 * as the untagged command depth
934 * Lock Status: None held on entry
936 * Notes: Low level drivers may call this at any time and we will do
937 * "The Right Thing." We are interrupt context safe.
939 int scsi_track_queue_full(struct scsi_device
*sdev
, int depth
)
943 * Don't let QUEUE_FULLs on the same
944 * jiffies count, they could all be from
947 if ((jiffies
>> 4) == (sdev
->last_queue_full_time
>> 4))
950 sdev
->last_queue_full_time
= jiffies
;
951 if (sdev
->last_queue_full_depth
!= depth
) {
952 sdev
->last_queue_full_count
= 1;
953 sdev
->last_queue_full_depth
= depth
;
955 sdev
->last_queue_full_count
++;
958 if (sdev
->last_queue_full_count
<= 10)
960 if (sdev
->last_queue_full_depth
< 8) {
961 /* Drop back to untagged */
962 scsi_adjust_queue_depth(sdev
, 0, sdev
->host
->cmd_per_lun
);
966 if (sdev
->ordered_tags
)
967 scsi_adjust_queue_depth(sdev
, MSG_ORDERED_TAG
, depth
);
969 scsi_adjust_queue_depth(sdev
, MSG_SIMPLE_TAG
, depth
);
972 EXPORT_SYMBOL(scsi_track_queue_full
);
975 * scsi_vpd_inquiry - Request a device provide us with a VPD page
976 * @sdev: The device to ask
977 * @buffer: Where to put the result
978 * @page: Which Vital Product Data to return
979 * @len: The length of the buffer
981 * This is an internal helper function. You probably want to use
982 * scsi_get_vpd_page instead.
984 * Returns 0 on success or a negative error number.
986 static int scsi_vpd_inquiry(struct scsi_device
*sdev
, unsigned char *buffer
,
987 u8 page
, unsigned len
)
990 unsigned char cmd
[16];
993 cmd
[1] = 1; /* EVPD */
997 cmd
[5] = 0; /* Control byte */
1000 * I'm not convinced we need to try quite this hard to get VPD, but
1001 * all the existing users tried this hard.
1003 result
= scsi_execute_req(sdev
, cmd
, DMA_FROM_DEVICE
, buffer
,
1004 len
, NULL
, 30 * HZ
, 3, NULL
);
1008 /* Sanity check that we got the page back that we asked for */
1009 if (buffer
[1] != page
)
1016 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
1017 * @sdev: The device to ask
1018 * @page: Which Vital Product Data to return
1019 * @buf: where to store the VPD
1020 * @buf_len: number of bytes in the VPD buffer area
1022 * SCSI devices may optionally supply Vital Product Data. Each 'page'
1023 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
1024 * If the device supports this VPD page, this routine returns a pointer
1025 * to a buffer containing the data from that page. The caller is
1026 * responsible for calling kfree() on this pointer when it is no longer
1027 * needed. If we cannot retrieve the VPD page this routine returns %NULL.
1029 int scsi_get_vpd_page(struct scsi_device
*sdev
, u8 page
, unsigned char *buf
,
1034 if (sdev
->skip_vpd_pages
)
1037 /* Ask for all the pages supported by this device */
1038 result
= scsi_vpd_inquiry(sdev
, buf
, 0, buf_len
);
1042 /* If the user actually wanted this page, we can skip the rest */
1046 for (i
= 0; i
< min((int)buf
[3], buf_len
- 4); i
++)
1047 if (buf
[i
+ 4] == page
)
1050 if (i
< buf
[3] && i
>= buf_len
- 4)
1051 /* ran off the end of the buffer, give us benefit of doubt */
1053 /* The device claims it doesn't support the requested page */
1057 result
= scsi_vpd_inquiry(sdev
, buf
, page
, buf_len
);
1066 EXPORT_SYMBOL_GPL(scsi_get_vpd_page
);
1069 * scsi_report_opcode - Find out if a given command opcode is supported
1070 * @sdev: scsi device to query
1071 * @buffer: scratch buffer (must be at least 20 bytes long)
1072 * @len: length of buffer
1073 * @opcode: opcode for command to look up
1075 * Uses the REPORT SUPPORTED OPERATION CODES to look up the given
1076 * opcode. Returns -EINVAL if RSOC fails, 0 if the command opcode is
1077 * unsupported and 1 if the device claims to support the command.
1079 int scsi_report_opcode(struct scsi_device
*sdev
, unsigned char *buffer
,
1080 unsigned int len
, unsigned char opcode
)
1082 unsigned char cmd
[16];
1083 struct scsi_sense_hdr sshdr
;
1086 if (sdev
->no_report_opcodes
|| sdev
->scsi_level
< SCSI_SPC_3
)
1090 cmd
[0] = MAINTENANCE_IN
;
1091 cmd
[1] = MI_REPORT_SUPPORTED_OPERATION_CODES
;
1092 cmd
[2] = 1; /* One command format */
1094 put_unaligned_be32(len
, &cmd
[6]);
1095 memset(buffer
, 0, len
);
1097 result
= scsi_execute_req(sdev
, cmd
, DMA_FROM_DEVICE
, buffer
, len
,
1098 &sshdr
, 30 * HZ
, 3, NULL
);
1100 if (result
&& scsi_sense_valid(&sshdr
) &&
1101 sshdr
.sense_key
== ILLEGAL_REQUEST
&&
1102 (sshdr
.asc
== 0x20 || sshdr
.asc
== 0x24) && sshdr
.ascq
== 0x00)
1105 if ((buffer
[1] & 3) == 3) /* Command supported */
1110 EXPORT_SYMBOL(scsi_report_opcode
);
1113 * scsi_device_get - get an additional reference to a scsi_device
1114 * @sdev: device to get a reference to
1116 * Description: Gets a reference to the scsi_device and increments the use count
1117 * of the underlying LLDD module. You must hold host_lock of the
1118 * parent Scsi_Host or already have a reference when calling this.
1120 int scsi_device_get(struct scsi_device
*sdev
)
1122 if (sdev
->sdev_state
== SDEV_DEL
)
1124 if (!get_device(&sdev
->sdev_gendev
))
1126 /* We can fail this if we're doing SCSI operations
1127 * from module exit (like cache flush) */
1128 try_module_get(sdev
->host
->hostt
->module
);
1132 EXPORT_SYMBOL(scsi_device_get
);
1135 * scsi_device_put - release a reference to a scsi_device
1136 * @sdev: device to release a reference on.
1138 * Description: Release a reference to the scsi_device and decrements the use
1139 * count of the underlying LLDD module. The device is freed once the last
1142 void scsi_device_put(struct scsi_device
*sdev
)
1144 #ifdef CONFIG_MODULE_UNLOAD
1145 struct module
*module
= sdev
->host
->hostt
->module
;
1147 /* The module refcount will be zero if scsi_device_get()
1148 * was called from a module removal routine */
1149 if (module
&& module_refcount(module
) != 0)
1152 put_device(&sdev
->sdev_gendev
);
1154 EXPORT_SYMBOL(scsi_device_put
);
1156 /* helper for shost_for_each_device, see that for documentation */
1157 struct scsi_device
*__scsi_iterate_devices(struct Scsi_Host
*shost
,
1158 struct scsi_device
*prev
)
1160 struct list_head
*list
= (prev
? &prev
->siblings
: &shost
->__devices
);
1161 struct scsi_device
*next
= NULL
;
1162 unsigned long flags
;
1164 spin_lock_irqsave(shost
->host_lock
, flags
);
1165 while (list
->next
!= &shost
->__devices
) {
1166 next
= list_entry(list
->next
, struct scsi_device
, siblings
);
1167 /* skip devices that we can't get a reference to */
1168 if (!scsi_device_get(next
))
1173 spin_unlock_irqrestore(shost
->host_lock
, flags
);
1176 scsi_device_put(prev
);
1179 EXPORT_SYMBOL(__scsi_iterate_devices
);
1182 * starget_for_each_device - helper to walk all devices of a target
1183 * @starget: target whose devices we want to iterate over.
1184 * @data: Opaque passed to each function call.
1185 * @fn: Function to call on each device
1187 * This traverses over each device of @starget. The devices have
1188 * a reference that must be released by scsi_host_put when breaking
1191 void starget_for_each_device(struct scsi_target
*starget
, void *data
,
1192 void (*fn
)(struct scsi_device
*, void *))
1194 struct Scsi_Host
*shost
= dev_to_shost(starget
->dev
.parent
);
1195 struct scsi_device
*sdev
;
1197 shost_for_each_device(sdev
, shost
) {
1198 if ((sdev
->channel
== starget
->channel
) &&
1199 (sdev
->id
== starget
->id
))
1203 EXPORT_SYMBOL(starget_for_each_device
);
1206 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
1207 * @starget: target whose devices we want to iterate over.
1208 * @data: parameter for callback @fn()
1209 * @fn: callback function that is invoked for each device
1211 * This traverses over each device of @starget. It does _not_
1212 * take a reference on the scsi_device, so the whole loop must be
1213 * protected by shost->host_lock.
1215 * Note: The only reason why drivers would want to use this is because
1216 * they need to access the device list in irq context. Otherwise you
1217 * really want to use starget_for_each_device instead.
1219 void __starget_for_each_device(struct scsi_target
*starget
, void *data
,
1220 void (*fn
)(struct scsi_device
*, void *))
1222 struct Scsi_Host
*shost
= dev_to_shost(starget
->dev
.parent
);
1223 struct scsi_device
*sdev
;
1225 __shost_for_each_device(sdev
, shost
) {
1226 if ((sdev
->channel
== starget
->channel
) &&
1227 (sdev
->id
== starget
->id
))
1231 EXPORT_SYMBOL(__starget_for_each_device
);
1234 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
1235 * @starget: SCSI target pointer
1236 * @lun: SCSI Logical Unit Number
1238 * Description: Looks up the scsi_device with the specified @lun for a given
1239 * @starget. The returned scsi_device does not have an additional
1240 * reference. You must hold the host's host_lock over this call and
1241 * any access to the returned scsi_device. A scsi_device in state
1242 * SDEV_DEL is skipped.
1244 * Note: The only reason why drivers should use this is because
1245 * they need to access the device list in irq context. Otherwise you
1246 * really want to use scsi_device_lookup_by_target instead.
1248 struct scsi_device
*__scsi_device_lookup_by_target(struct scsi_target
*starget
,
1251 struct scsi_device
*sdev
;
1253 list_for_each_entry(sdev
, &starget
->devices
, same_target_siblings
) {
1254 if (sdev
->sdev_state
== SDEV_DEL
)
1256 if (sdev
->lun
==lun
)
1262 EXPORT_SYMBOL(__scsi_device_lookup_by_target
);
1265 * scsi_device_lookup_by_target - find a device given the target
1266 * @starget: SCSI target pointer
1267 * @lun: SCSI Logical Unit Number
1269 * Description: Looks up the scsi_device with the specified @lun for a given
1270 * @starget. The returned scsi_device has an additional reference that
1271 * needs to be released with scsi_device_put once you're done with it.
1273 struct scsi_device
*scsi_device_lookup_by_target(struct scsi_target
*starget
,
1276 struct scsi_device
*sdev
;
1277 struct Scsi_Host
*shost
= dev_to_shost(starget
->dev
.parent
);
1278 unsigned long flags
;
1280 spin_lock_irqsave(shost
->host_lock
, flags
);
1281 sdev
= __scsi_device_lookup_by_target(starget
, lun
);
1282 if (sdev
&& scsi_device_get(sdev
))
1284 spin_unlock_irqrestore(shost
->host_lock
, flags
);
1288 EXPORT_SYMBOL(scsi_device_lookup_by_target
);
1291 * __scsi_device_lookup - find a device given the host (UNLOCKED)
1292 * @shost: SCSI host pointer
1293 * @channel: SCSI channel (zero if only one channel)
1294 * @id: SCSI target number (physical unit number)
1295 * @lun: SCSI Logical Unit Number
1297 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1298 * for a given host. The returned scsi_device does not have an additional
1299 * reference. You must hold the host's host_lock over this call and any access
1300 * to the returned scsi_device.
1302 * Note: The only reason why drivers would want to use this is because
1303 * they need to access the device list in irq context. Otherwise you
1304 * really want to use scsi_device_lookup instead.
1306 struct scsi_device
*__scsi_device_lookup(struct Scsi_Host
*shost
,
1307 uint channel
, uint id
, uint lun
)
1309 struct scsi_device
*sdev
;
1311 list_for_each_entry(sdev
, &shost
->__devices
, siblings
) {
1312 if (sdev
->channel
== channel
&& sdev
->id
== id
&&
1319 EXPORT_SYMBOL(__scsi_device_lookup
);
1322 * scsi_device_lookup - find a device given the host
1323 * @shost: SCSI host pointer
1324 * @channel: SCSI channel (zero if only one channel)
1325 * @id: SCSI target number (physical unit number)
1326 * @lun: SCSI Logical Unit Number
1328 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1329 * for a given host. The returned scsi_device has an additional reference that
1330 * needs to be released with scsi_device_put once you're done with it.
1332 struct scsi_device
*scsi_device_lookup(struct Scsi_Host
*shost
,
1333 uint channel
, uint id
, uint lun
)
1335 struct scsi_device
*sdev
;
1336 unsigned long flags
;
1338 spin_lock_irqsave(shost
->host_lock
, flags
);
1339 sdev
= __scsi_device_lookup(shost
, channel
, id
, lun
);
1340 if (sdev
&& scsi_device_get(sdev
))
1342 spin_unlock_irqrestore(shost
->host_lock
, flags
);
1346 EXPORT_SYMBOL(scsi_device_lookup
);
1348 MODULE_DESCRIPTION("SCSI core");
1349 MODULE_LICENSE("GPL");
1351 module_param(scsi_logging_level
, int, S_IRUGO
|S_IWUSR
);
1352 MODULE_PARM_DESC(scsi_logging_level
, "a bit mask of logging levels");
1354 static int __init
init_scsi(void)
1358 error
= scsi_init_queue();
1361 error
= scsi_init_procfs();
1364 error
= scsi_init_devinfo();
1366 goto cleanup_procfs
;
1367 error
= scsi_init_hosts();
1369 goto cleanup_devlist
;
1370 error
= scsi_init_sysctl();
1373 error
= scsi_sysfs_register();
1375 goto cleanup_sysctl
;
1377 scsi_netlink_init();
1379 printk(KERN_NOTICE
"SCSI subsystem initialized\n");
1387 scsi_exit_devinfo();
1392 printk(KERN_ERR
"SCSI subsystem failed to initialize, error = %d\n",
1397 static void __exit
exit_scsi(void)
1399 scsi_netlink_exit();
1400 scsi_sysfs_unregister();
1403 scsi_exit_devinfo();
1406 async_unregister_domain(&scsi_sd_probe_domain
);
1409 subsys_initcall(init_scsi
);
1410 module_exit(exit_scsi
);