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>
58 #include <scsi/scsi.h>
59 #include <scsi/scsi_cmnd.h>
60 #include <scsi/scsi_dbg.h>
61 #include <scsi/scsi_device.h>
62 #include <scsi/scsi_eh.h>
63 #include <scsi/scsi_host.h>
64 #include <scsi/scsi_tcq.h>
66 #include "scsi_priv.h"
67 #include "scsi_logging.h"
69 static void scsi_done(struct scsi_cmnd
*cmd
);
72 * Definitions and constants.
75 #define MIN_RESET_DELAY (2*HZ)
77 /* Do not call reset on error if we just did a reset within 15 sec. */
78 #define MIN_RESET_PERIOD (15*HZ)
81 * Macro to determine the size of SCSI command. This macro takes vendor
82 * unique commands into account. SCSI commands in groups 6 and 7 are
83 * vendor unique and we will depend upon the command length being
84 * supplied correctly in cmd_len.
86 #define CDB_SIZE(cmd) (((((cmd)->cmnd[0] >> 5) & 7) < 6) ? \
87 COMMAND_SIZE((cmd)->cmnd[0]) : (cmd)->cmd_len)
90 * Note - the initial logging level can be set here to log events at boot time.
91 * After the system is up, you may enable logging via the /proc interface.
93 unsigned int scsi_logging_level
;
94 #if defined(CONFIG_SCSI_LOGGING)
95 EXPORT_SYMBOL(scsi_logging_level
);
98 /* NB: These are exposed through /proc/scsi/scsi and form part of the ABI.
99 * You may not alter any existing entry (although adding new ones is
100 * encouraged once assigned by ANSI/INCITS T10
102 static const char *const scsi_device_types
[] = {
124 const char * scsi_device_type(unsigned type
)
127 return "Well-known LUN ";
130 if (type
>= ARRAY_SIZE(scsi_device_types
))
132 return scsi_device_types
[type
];
135 EXPORT_SYMBOL(scsi_device_type
);
137 struct scsi_host_cmd_pool
{
138 struct kmem_cache
*cmd_slab
;
139 struct kmem_cache
*sense_slab
;
143 unsigned int slab_flags
;
147 static struct scsi_host_cmd_pool scsi_cmd_pool
= {
148 .cmd_name
= "scsi_cmd_cache",
149 .sense_name
= "scsi_sense_cache",
150 .slab_flags
= SLAB_HWCACHE_ALIGN
,
153 static struct scsi_host_cmd_pool scsi_cmd_dma_pool
= {
154 .cmd_name
= "scsi_cmd_cache(DMA)",
155 .sense_name
= "scsi_sense_cache(DMA)",
156 .slab_flags
= SLAB_HWCACHE_ALIGN
|SLAB_CACHE_DMA
,
157 .gfp_mask
= __GFP_DMA
,
160 static DEFINE_MUTEX(host_cmd_pool_mutex
);
163 * scsi_pool_alloc_command - internal function to get a fully allocated command
164 * @pool: slab pool to allocate the command from
165 * @gfp_mask: mask for the allocation
167 * Returns a fully allocated command (with the allied sense buffer) or
170 static struct scsi_cmnd
*
171 scsi_pool_alloc_command(struct scsi_host_cmd_pool
*pool
, gfp_t gfp_mask
)
173 struct scsi_cmnd
*cmd
;
175 cmd
= kmem_cache_zalloc(pool
->cmd_slab
, gfp_mask
| pool
->gfp_mask
);
179 cmd
->sense_buffer
= kmem_cache_alloc(pool
->sense_slab
,
180 gfp_mask
| pool
->gfp_mask
);
181 if (!cmd
->sense_buffer
) {
182 kmem_cache_free(pool
->cmd_slab
, cmd
);
190 * scsi_pool_free_command - internal function to release a command
191 * @pool: slab pool to allocate the command from
192 * @cmd: command to release
194 * the command must previously have been allocated by
195 * scsi_pool_alloc_command.
198 scsi_pool_free_command(struct scsi_host_cmd_pool
*pool
,
199 struct scsi_cmnd
*cmd
)
201 kmem_cache_free(pool
->sense_slab
, cmd
->sense_buffer
);
202 kmem_cache_free(pool
->cmd_slab
, cmd
);
206 * __scsi_get_command - Allocate a struct scsi_cmnd
207 * @shost: host to transmit command
208 * @gfp_mask: allocation mask
210 * Description: allocate a struct scsi_cmd from host's slab, recycling from the
211 * host's free_list if necessary.
213 struct scsi_cmnd
*__scsi_get_command(struct Scsi_Host
*shost
, gfp_t gfp_mask
)
215 struct scsi_cmnd
*cmd
;
218 cmd
= scsi_pool_alloc_command(shost
->cmd_pool
, gfp_mask
);
220 if (unlikely(!cmd
)) {
223 spin_lock_irqsave(&shost
->free_list_lock
, flags
);
224 if (likely(!list_empty(&shost
->free_list
))) {
225 cmd
= list_entry(shost
->free_list
.next
,
226 struct scsi_cmnd
, list
);
227 list_del_init(&cmd
->list
);
229 spin_unlock_irqrestore(&shost
->free_list_lock
, flags
);
232 buf
= cmd
->sense_buffer
;
233 memset(cmd
, 0, sizeof(*cmd
));
234 cmd
->sense_buffer
= buf
;
240 EXPORT_SYMBOL_GPL(__scsi_get_command
);
243 * Function: scsi_get_command()
245 * Purpose: Allocate and setup a scsi command block
247 * Arguments: dev - parent scsi device
248 * gfp_mask- allocator flags
250 * Returns: The allocated scsi command structure.
252 struct scsi_cmnd
*scsi_get_command(struct scsi_device
*dev
, gfp_t gfp_mask
)
254 struct scsi_cmnd
*cmd
;
256 /* Bail if we can't get a reference to the device */
257 if (!get_device(&dev
->sdev_gendev
))
260 cmd
= __scsi_get_command(dev
->host
, gfp_mask
);
262 if (likely(cmd
!= NULL
)) {
266 init_timer(&cmd
->eh_timeout
);
267 INIT_LIST_HEAD(&cmd
->list
);
268 spin_lock_irqsave(&dev
->list_lock
, flags
);
269 list_add_tail(&cmd
->list
, &dev
->cmd_list
);
270 spin_unlock_irqrestore(&dev
->list_lock
, flags
);
271 cmd
->jiffies_at_alloc
= jiffies
;
273 put_device(&dev
->sdev_gendev
);
277 EXPORT_SYMBOL(scsi_get_command
);
279 void __scsi_put_command(struct Scsi_Host
*shost
, struct scsi_cmnd
*cmd
,
284 /* changing locks here, don't need to restore the irq state */
285 spin_lock_irqsave(&shost
->free_list_lock
, flags
);
286 if (unlikely(list_empty(&shost
->free_list
))) {
287 list_add(&cmd
->list
, &shost
->free_list
);
290 spin_unlock_irqrestore(&shost
->free_list_lock
, flags
);
292 if (likely(cmd
!= NULL
))
293 scsi_pool_free_command(shost
->cmd_pool
, cmd
);
297 EXPORT_SYMBOL(__scsi_put_command
);
300 * Function: scsi_put_command()
302 * Purpose: Free a scsi command block
304 * Arguments: cmd - command block to free
308 * Notes: The command must not belong to any lists.
310 void scsi_put_command(struct scsi_cmnd
*cmd
)
312 struct scsi_device
*sdev
= cmd
->device
;
315 /* serious error if the command hasn't come from a device list */
316 spin_lock_irqsave(&cmd
->device
->list_lock
, flags
);
317 BUG_ON(list_empty(&cmd
->list
));
318 list_del_init(&cmd
->list
);
319 spin_unlock_irqrestore(&cmd
->device
->list_lock
, flags
);
321 __scsi_put_command(cmd
->device
->host
, cmd
, &sdev
->sdev_gendev
);
323 EXPORT_SYMBOL(scsi_put_command
);
325 static struct scsi_host_cmd_pool
*scsi_get_host_cmd_pool(gfp_t gfp_mask
)
327 struct scsi_host_cmd_pool
*retval
= NULL
, *pool
;
329 * Select a command slab for this host and create it if not
332 mutex_lock(&host_cmd_pool_mutex
);
333 pool
= (gfp_mask
& __GFP_DMA
) ? &scsi_cmd_dma_pool
:
336 pool
->cmd_slab
= kmem_cache_create(pool
->cmd_name
,
337 sizeof(struct scsi_cmnd
), 0,
338 pool
->slab_flags
, NULL
, NULL
);
342 pool
->sense_slab
= kmem_cache_create(pool
->sense_name
,
343 SCSI_SENSE_BUFFERSIZE
, 0,
344 pool
->slab_flags
, NULL
, NULL
);
345 if (!pool
->sense_slab
) {
346 kmem_cache_destroy(pool
->cmd_slab
);
354 mutex_unlock(&host_cmd_pool_mutex
);
358 static void scsi_put_host_cmd_pool(gfp_t gfp_mask
)
360 struct scsi_host_cmd_pool
*pool
;
362 mutex_lock(&host_cmd_pool_mutex
);
363 pool
= (gfp_mask
& __GFP_DMA
) ? &scsi_cmd_dma_pool
:
366 * This may happen if a driver has a mismatched get and put
367 * of the command pool; the driver should be implicated in
370 BUG_ON(pool
->users
== 0);
372 if (!--pool
->users
) {
373 kmem_cache_destroy(pool
->cmd_slab
);
374 kmem_cache_destroy(pool
->sense_slab
);
376 mutex_unlock(&host_cmd_pool_mutex
);
380 * scsi_allocate_command - get a fully allocated SCSI command
381 * @gfp_mask: allocation mask
383 * This function is for use outside of the normal host based pools.
384 * It allocates the relevant command and takes an additional reference
385 * on the pool it used. This function *must* be paired with
386 * scsi_free_command which also has the identical mask, otherwise the
387 * free pool counts will eventually go wrong and you'll trigger a bug.
389 * This function should *only* be used by drivers that need a static
390 * command allocation at start of day for internal functions.
392 struct scsi_cmnd
*scsi_allocate_command(gfp_t gfp_mask
)
394 struct scsi_host_cmd_pool
*pool
= scsi_get_host_cmd_pool(gfp_mask
);
399 return scsi_pool_alloc_command(pool
, gfp_mask
);
401 EXPORT_SYMBOL(scsi_allocate_command
);
404 * scsi_free_command - free a command allocated by scsi_allocate_command
405 * @gfp_mask: mask used in the original allocation
406 * @cmd: command to free
408 * Note: using the original allocation mask is vital because that's
409 * what determines which command pool we use to free the command. Any
410 * mismatch will cause the system to BUG eventually.
412 void scsi_free_command(gfp_t gfp_mask
, struct scsi_cmnd
*cmd
)
414 struct scsi_host_cmd_pool
*pool
= scsi_get_host_cmd_pool(gfp_mask
);
417 * this could trigger if the mask to scsi_allocate_command
418 * doesn't match this mask. Otherwise we're guaranteed that this
419 * succeeds because scsi_allocate_command must have taken a reference
424 scsi_pool_free_command(pool
, cmd
);
426 * scsi_put_host_cmd_pool is called twice; once to release the
427 * reference we took above, and once to release the reference
428 * originally taken by scsi_allocate_command
430 scsi_put_host_cmd_pool(gfp_mask
);
431 scsi_put_host_cmd_pool(gfp_mask
);
433 EXPORT_SYMBOL(scsi_free_command
);
436 * scsi_setup_command_freelist - Setup the command freelist for a scsi host.
437 * @shost: host to allocate the freelist for.
439 * Description: The command freelist protects against system-wide out of memory
440 * deadlock by preallocating one SCSI command structure for each host, so the
441 * system can always write to a swap file on a device associated with that host.
445 int scsi_setup_command_freelist(struct Scsi_Host
*shost
)
447 struct scsi_cmnd
*cmd
;
448 const gfp_t gfp_mask
= shost
->unchecked_isa_dma
? GFP_DMA
: GFP_KERNEL
;
450 spin_lock_init(&shost
->free_list_lock
);
451 INIT_LIST_HEAD(&shost
->free_list
);
453 shost
->cmd_pool
= scsi_get_host_cmd_pool(gfp_mask
);
455 if (!shost
->cmd_pool
)
459 * Get one backup command for this host.
461 cmd
= scsi_pool_alloc_command(shost
->cmd_pool
, gfp_mask
);
463 scsi_put_host_cmd_pool(gfp_mask
);
464 shost
->cmd_pool
= NULL
;
467 list_add(&cmd
->list
, &shost
->free_list
);
472 * Function: scsi_destroy_command_freelist()
474 * Purpose: Release the command freelist for a scsi host.
476 * Arguments: shost - host that's freelist is going to be destroyed
478 void scsi_destroy_command_freelist(struct Scsi_Host
*shost
)
481 * If cmd_pool is NULL the free list was not initialized, so
482 * do not attempt to release resources.
484 if (!shost
->cmd_pool
)
487 while (!list_empty(&shost
->free_list
)) {
488 struct scsi_cmnd
*cmd
;
490 cmd
= list_entry(shost
->free_list
.next
, struct scsi_cmnd
, list
);
491 list_del_init(&cmd
->list
);
492 scsi_pool_free_command(shost
->cmd_pool
, cmd
);
494 shost
->cmd_pool
= NULL
;
495 scsi_put_host_cmd_pool(shost
->unchecked_isa_dma
? GFP_DMA
: GFP_KERNEL
);
498 #ifdef CONFIG_SCSI_LOGGING
499 void scsi_log_send(struct scsi_cmnd
*cmd
)
504 * If ML QUEUE log level is greater than or equal to:
506 * 1: nothing (match completion)
508 * 2: log opcode + command of all commands
510 * 3: same as 2 plus dump cmd address
512 * 4: same as 3 plus dump extra junk
514 if (unlikely(scsi_logging_level
)) {
515 level
= SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT
,
516 SCSI_LOG_MLQUEUE_BITS
);
518 scmd_printk(KERN_INFO
, cmd
, "Send: ");
520 printk("0x%p ", cmd
);
522 scsi_print_command(cmd
);
524 printk(KERN_INFO
"buffer = 0x%p, bufflen = %d,"
525 " done = 0x%p, queuecommand 0x%p\n",
526 scsi_sglist(cmd
), scsi_bufflen(cmd
),
528 cmd
->device
->host
->hostt
->queuecommand
);
535 void scsi_log_completion(struct scsi_cmnd
*cmd
, int disposition
)
540 * If ML COMPLETE log level is greater than or equal to:
542 * 1: log disposition, result, opcode + command, and conditionally
543 * sense data for failures or non SUCCESS dispositions.
545 * 2: same as 1 but for all command completions.
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_MLCOMPLETE_SHIFT
,
553 SCSI_LOG_MLCOMPLETE_BITS
);
554 if (((level
> 0) && (cmd
->result
|| disposition
!= SUCCESS
)) ||
556 scmd_printk(KERN_INFO
, cmd
, "Done: ");
558 printk("0x%p ", cmd
);
560 * Dump truncated values, so we usually fit within
563 switch (disposition
) {
578 * If called via scsi_times_out.
585 scsi_print_result(cmd
);
586 scsi_print_command(cmd
);
587 if (status_byte(cmd
->result
) & CHECK_CONDITION
)
588 scsi_print_sense("", cmd
);
590 scmd_printk(KERN_INFO
, cmd
,
591 "scsi host busy %d failed %d\n",
592 cmd
->device
->host
->host_busy
,
593 cmd
->device
->host
->host_failed
);
600 * Assign a serial number and pid to the request for error recovery
601 * and debugging purposes. Protected by the Host_Lock of host.
603 static inline void scsi_cmd_get_serial(struct Scsi_Host
*host
, struct scsi_cmnd
*cmd
)
605 cmd
->serial_number
= host
->cmd_serial_number
++;
606 if (cmd
->serial_number
== 0)
607 cmd
->serial_number
= host
->cmd_serial_number
++;
609 cmd
->pid
= host
->cmd_pid
++;
611 cmd
->pid
= host
->cmd_pid
++;
615 * Function: scsi_dispatch_command
617 * Purpose: Dispatch a command to the low-level driver.
619 * Arguments: cmd - command block we are dispatching.
623 int scsi_dispatch_cmd(struct scsi_cmnd
*cmd
)
625 struct Scsi_Host
*host
= cmd
->device
->host
;
626 unsigned long flags
= 0;
627 unsigned long timeout
;
630 /* check if the device is still usable */
631 if (unlikely(cmd
->device
->sdev_state
== SDEV_DEL
)) {
632 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
633 * returns an immediate error upwards, and signals
634 * that the device is no longer present */
635 cmd
->result
= DID_NO_CONNECT
<< 16;
636 atomic_inc(&cmd
->device
->iorequest_cnt
);
638 /* return 0 (because the command has been processed) */
642 /* Check to see if the scsi lld put this device into state SDEV_BLOCK. */
643 if (unlikely(cmd
->device
->sdev_state
== SDEV_BLOCK
)) {
645 * in SDEV_BLOCK, the command is just put back on the device
646 * queue. The suspend state has already blocked the queue so
647 * future requests should not occur until the device
648 * transitions out of the suspend state.
650 scsi_queue_insert(cmd
, SCSI_MLQUEUE_DEVICE_BUSY
);
652 SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
655 * NOTE: rtn is still zero here because we don't need the
656 * queue to be plugged on return (it's already stopped)
662 * If SCSI-2 or lower, store the LUN value in cmnd.
664 if (cmd
->device
->scsi_level
<= SCSI_2
&&
665 cmd
->device
->scsi_level
!= SCSI_UNKNOWN
) {
666 cmd
->cmnd
[1] = (cmd
->cmnd
[1] & 0x1f) |
667 (cmd
->device
->lun
<< 5 & 0xe0);
671 * We will wait MIN_RESET_DELAY clock ticks after the last reset so
672 * we can avoid the drive not being ready.
674 timeout
= host
->last_reset
+ MIN_RESET_DELAY
;
676 if (host
->resetting
&& time_before(jiffies
, timeout
)) {
677 int ticks_remaining
= timeout
- jiffies
;
679 * NOTE: This may be executed from within an interrupt
680 * handler! This is bad, but for now, it'll do. The irq
681 * level of the interrupt handler has been masked out by the
682 * platform dependent interrupt handling code already, so the
683 * sti() here will not cause another call to the SCSI host's
684 * interrupt handler (assuming there is one irq-level per
687 while (--ticks_remaining
>= 0)
688 mdelay(1 + 999 / HZ
);
693 * AK: unlikely race here: for some reason the timer could
694 * expire before the serial number is set up below.
696 scsi_add_timer(cmd
, cmd
->timeout_per_command
, scsi_times_out
);
701 * We will use a queued command if possible, otherwise we will
702 * emulate the queuing and calling of completion function ourselves.
704 atomic_inc(&cmd
->device
->iorequest_cnt
);
707 * Before we queue this command, check if the command
708 * length exceeds what the host adapter can handle.
710 if (CDB_SIZE(cmd
) > cmd
->device
->host
->max_cmd_len
) {
712 printk("queuecommand : command too long.\n"));
713 cmd
->result
= (DID_ABORT
<< 16);
719 spin_lock_irqsave(host
->host_lock
, flags
);
720 scsi_cmd_get_serial(host
, cmd
);
722 if (unlikely(host
->shost_state
== SHOST_DEL
)) {
723 cmd
->result
= (DID_NO_CONNECT
<< 16);
726 rtn
= host
->hostt
->queuecommand(cmd
, scsi_done
);
728 spin_unlock_irqrestore(host
->host_lock
, flags
);
730 if (scsi_delete_timer(cmd
)) {
731 atomic_inc(&cmd
->device
->iodone_cnt
);
732 scsi_queue_insert(cmd
,
733 (rtn
== SCSI_MLQUEUE_DEVICE_BUSY
) ?
734 rtn
: SCSI_MLQUEUE_HOST_BUSY
);
737 printk("queuecommand : request rejected\n"));
741 SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
746 * scsi_req_abort_cmd -- Request command recovery for the specified command
747 * cmd: pointer to the SCSI command of interest
749 * This function requests that SCSI Core start recovery for the
750 * command by deleting the timer and adding the command to the eh
751 * queue. It can be called by either LLDDs or SCSI Core. LLDDs who
752 * implement their own error recovery MAY ignore the timeout event if
753 * they generated scsi_req_abort_cmd.
755 void scsi_req_abort_cmd(struct scsi_cmnd
*cmd
)
757 if (!scsi_delete_timer(cmd
))
761 EXPORT_SYMBOL(scsi_req_abort_cmd
);
764 * scsi_done - Enqueue the finished SCSI command into the done queue.
765 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
766 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
768 * This function is the mid-level's (SCSI Core) interrupt routine, which
769 * regains ownership of the SCSI command (de facto) from a LLDD, and enqueues
770 * the command to the done queue for further processing.
772 * This is the producer of the done queue who enqueues at the tail.
774 * This function is interrupt context safe.
776 static void scsi_done(struct scsi_cmnd
*cmd
)
779 * We don't have to worry about this one timing out any more.
780 * If we are unable to remove the timer, then the command
781 * has already timed out. In which case, we have no choice but to
782 * let the timeout function run, as we have no idea where in fact
783 * that function could really be. It might be on another processor,
786 if (!scsi_delete_timer(cmd
))
791 /* Private entry to scsi_done() to complete a command when the timer
792 * isn't running --- used by scsi_times_out */
793 void __scsi_done(struct scsi_cmnd
*cmd
)
795 struct request
*rq
= cmd
->request
;
798 * Set the serial numbers back to zero
800 cmd
->serial_number
= 0;
802 atomic_inc(&cmd
->device
->iodone_cnt
);
804 atomic_inc(&cmd
->device
->ioerr_cnt
);
809 * The uptodate/nbytes values don't matter, as we allow partial
810 * completes and thus will check this in the softirq callback
812 rq
->completion_data
= cmd
;
813 blk_complete_request(rq
);
817 * Function: scsi_finish_command
819 * Purpose: Pass command off to upper layer for finishing of I/O
820 * request, waking processes that are waiting on results,
823 void scsi_finish_command(struct scsi_cmnd
*cmd
)
825 struct scsi_device
*sdev
= cmd
->device
;
826 struct Scsi_Host
*shost
= sdev
->host
;
828 scsi_device_unbusy(sdev
);
831 * Clear the flags which say that the device/host is no longer
832 * capable of accepting new commands. These are set in scsi_queue.c
833 * for both the queue full condition on a device, and for a
834 * host full condition on the host.
836 * XXX(hch): What about locking?
838 shost
->host_blocked
= 0;
839 sdev
->device_blocked
= 0;
842 * If we have valid sense information, then some kind of recovery
843 * must have taken place. Make a note of this.
845 if (SCSI_SENSE_VALID(cmd
))
846 cmd
->result
|= (DRIVER_SENSE
<< 24);
848 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO
, sdev
,
849 "Notifying upper driver of completion "
850 "(result %x)\n", cmd
->result
));
854 EXPORT_SYMBOL(scsi_finish_command
);
857 * Function: scsi_adjust_queue_depth()
859 * Purpose: Allow low level drivers to tell us to change the queue depth
860 * on a specific SCSI device
862 * Arguments: sdev - SCSI Device in question
863 * tagged - Do we use tagged queueing (non-0) or do we treat
864 * this device as an untagged device (0)
865 * tags - Number of tags allowed if tagged queueing enabled,
866 * or number of commands the low level driver can
867 * queue up in non-tagged mode (as per cmd_per_lun).
871 * Lock Status: None held on entry
873 * Notes: Low level drivers may call this at any time and we will do
874 * the right thing depending on whether or not the device is
875 * currently active and whether or not it even has the
876 * command blocks built yet.
878 void scsi_adjust_queue_depth(struct scsi_device
*sdev
, int tagged
, int tags
)
883 * refuse to set tagged depth to an unworkable size
888 spin_lock_irqsave(sdev
->request_queue
->queue_lock
, flags
);
890 /* Check to see if the queue is managed by the block layer
891 * if it is, and we fail to adjust the depth, exit */
892 if (blk_queue_tagged(sdev
->request_queue
) &&
893 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 * Function: scsi_track_queue_full()
923 * Purpose: This function will track successive QUEUE_FULL events on a
924 * specific SCSI device to determine if and when there is a
925 * need to adjust the queue depth on the device.
927 * Arguments: sdev - SCSI Device in question
928 * depth - Current number of outstanding SCSI commands on
929 * this device, not counting the one returned as
932 * Returns: 0 - No change needed
933 * >0 - Adjust queue depth to this new depth
934 * -1 - Drop back to untagged operation using host->cmd_per_lun
935 * as the untagged command depth
937 * Lock Status: None held on entry
939 * Notes: Low level drivers may call this at any time and we will do
940 * "The Right Thing." We are interrupt context safe.
942 int scsi_track_queue_full(struct scsi_device
*sdev
, int depth
)
944 if ((jiffies
>> 4) == sdev
->last_queue_full_time
)
947 sdev
->last_queue_full_time
= (jiffies
>> 4);
948 if (sdev
->last_queue_full_depth
!= depth
) {
949 sdev
->last_queue_full_count
= 1;
950 sdev
->last_queue_full_depth
= depth
;
952 sdev
->last_queue_full_count
++;
955 if (sdev
->last_queue_full_count
<= 10)
957 if (sdev
->last_queue_full_depth
< 8) {
958 /* Drop back to untagged */
959 scsi_adjust_queue_depth(sdev
, 0, sdev
->host
->cmd_per_lun
);
963 if (sdev
->ordered_tags
)
964 scsi_adjust_queue_depth(sdev
, MSG_ORDERED_TAG
, depth
);
966 scsi_adjust_queue_depth(sdev
, MSG_SIMPLE_TAG
, depth
);
969 EXPORT_SYMBOL(scsi_track_queue_full
);
972 * scsi_device_get - get an addition reference to a scsi_device
973 * @sdev: device to get a reference to
975 * Gets a reference to the scsi_device and increments the use count
976 * of the underlying LLDD module. You must hold host_lock of the
977 * parent Scsi_Host or already have a reference when calling this.
979 int scsi_device_get(struct scsi_device
*sdev
)
981 if (sdev
->sdev_state
== SDEV_DEL
)
983 if (!get_device(&sdev
->sdev_gendev
))
985 /* We can fail this if we're doing SCSI operations
986 * from module exit (like cache flush) */
987 try_module_get(sdev
->host
->hostt
->module
);
991 EXPORT_SYMBOL(scsi_device_get
);
994 * scsi_device_put - release a reference to a scsi_device
995 * @sdev: device to release a reference on.
997 * Release a reference to the scsi_device and decrements the use count
998 * of the underlying LLDD module. The device is freed once the last
1001 void scsi_device_put(struct scsi_device
*sdev
)
1003 #ifdef CONFIG_MODULE_UNLOAD
1004 struct module
*module
= sdev
->host
->hostt
->module
;
1006 /* The module refcount will be zero if scsi_device_get()
1007 * was called from a module removal routine */
1008 if (module
&& module_refcount(module
) != 0)
1011 put_device(&sdev
->sdev_gendev
);
1013 EXPORT_SYMBOL(scsi_device_put
);
1015 /* helper for shost_for_each_device, thus not documented */
1016 struct scsi_device
*__scsi_iterate_devices(struct Scsi_Host
*shost
,
1017 struct scsi_device
*prev
)
1019 struct list_head
*list
= (prev
? &prev
->siblings
: &shost
->__devices
);
1020 struct scsi_device
*next
= NULL
;
1021 unsigned long flags
;
1023 spin_lock_irqsave(shost
->host_lock
, flags
);
1024 while (list
->next
!= &shost
->__devices
) {
1025 next
= list_entry(list
->next
, struct scsi_device
, siblings
);
1026 /* skip devices that we can't get a reference to */
1027 if (!scsi_device_get(next
))
1032 spin_unlock_irqrestore(shost
->host_lock
, flags
);
1035 scsi_device_put(prev
);
1038 EXPORT_SYMBOL(__scsi_iterate_devices
);
1041 * starget_for_each_device - helper to walk all devices of a target
1042 * @starget: target whose devices we want to iterate over.
1044 * This traverses over each devices of @shost. The devices have
1045 * a reference that must be released by scsi_host_put when breaking
1048 void starget_for_each_device(struct scsi_target
*starget
, void * data
,
1049 void (*fn
)(struct scsi_device
*, void *))
1051 struct Scsi_Host
*shost
= dev_to_shost(starget
->dev
.parent
);
1052 struct scsi_device
*sdev
;
1054 shost_for_each_device(sdev
, shost
) {
1055 if ((sdev
->channel
== starget
->channel
) &&
1056 (sdev
->id
== starget
->id
))
1060 EXPORT_SYMBOL(starget_for_each_device
);
1063 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
1064 * @starget: SCSI target pointer
1065 * @lun: SCSI Logical Unit Number
1067 * Looks up the scsi_device with the specified @lun for a give
1068 * @starget. The returned scsi_device does not have an additional
1069 * reference. You must hold the host's host_lock over this call and
1070 * any access to the returned scsi_device. A scsi_device in state
1071 * SDEV_DEL is skipped.
1073 * Note: The only reason why drivers would want to use this is because
1074 * they're need to access the device list in irq context. Otherwise you
1075 * really want to use scsi_device_lookup_by_target instead.
1077 struct scsi_device
*__scsi_device_lookup_by_target(struct scsi_target
*starget
,
1080 struct scsi_device
*sdev
;
1082 list_for_each_entry(sdev
, &starget
->devices
, same_target_siblings
) {
1083 if (sdev
->sdev_state
== SDEV_DEL
)
1085 if (sdev
->lun
==lun
)
1091 EXPORT_SYMBOL(__scsi_device_lookup_by_target
);
1094 * scsi_device_lookup_by_target - find a device given the target
1095 * @starget: SCSI target pointer
1096 * @lun: SCSI Logical Unit Number
1098 * Looks up the scsi_device with the specified @channel, @id, @lun for a
1099 * give host. The returned scsi_device has an additional reference that
1100 * needs to be release with scsi_host_put once you're done with it.
1102 struct scsi_device
*scsi_device_lookup_by_target(struct scsi_target
*starget
,
1105 struct scsi_device
*sdev
;
1106 struct Scsi_Host
*shost
= dev_to_shost(starget
->dev
.parent
);
1107 unsigned long flags
;
1109 spin_lock_irqsave(shost
->host_lock
, flags
);
1110 sdev
= __scsi_device_lookup_by_target(starget
, lun
);
1111 if (sdev
&& scsi_device_get(sdev
))
1113 spin_unlock_irqrestore(shost
->host_lock
, flags
);
1117 EXPORT_SYMBOL(scsi_device_lookup_by_target
);
1120 * scsi_device_lookup - find a device given the host (UNLOCKED)
1121 * @shost: SCSI host pointer
1122 * @channel: SCSI channel (zero if only one channel)
1123 * @pun: SCSI target number (physical unit number)
1124 * @lun: SCSI Logical Unit Number
1126 * Looks up the scsi_device with the specified @channel, @id, @lun for a
1127 * give host. The returned scsi_device does not have an additional reference.
1128 * You must hold the host's host_lock over this call and any access to the
1129 * returned scsi_device.
1131 * Note: The only reason why drivers would want to use this is because
1132 * they're need to access the device list in irq context. Otherwise you
1133 * really want to use scsi_device_lookup instead.
1135 struct scsi_device
*__scsi_device_lookup(struct Scsi_Host
*shost
,
1136 uint channel
, uint id
, uint lun
)
1138 struct scsi_device
*sdev
;
1140 list_for_each_entry(sdev
, &shost
->__devices
, siblings
) {
1141 if (sdev
->channel
== channel
&& sdev
->id
== id
&&
1148 EXPORT_SYMBOL(__scsi_device_lookup
);
1151 * scsi_device_lookup - find a device given the host
1152 * @shost: SCSI host pointer
1153 * @channel: SCSI channel (zero if only one channel)
1154 * @id: SCSI target number (physical unit number)
1155 * @lun: SCSI Logical Unit Number
1157 * Looks up the scsi_device with the specified @channel, @id, @lun for a
1158 * give host. The returned scsi_device has an additional reference that
1159 * needs to be release with scsi_host_put once you're done with it.
1161 struct scsi_device
*scsi_device_lookup(struct Scsi_Host
*shost
,
1162 uint channel
, uint id
, uint lun
)
1164 struct scsi_device
*sdev
;
1165 unsigned long flags
;
1167 spin_lock_irqsave(shost
->host_lock
, flags
);
1168 sdev
= __scsi_device_lookup(shost
, channel
, id
, lun
);
1169 if (sdev
&& scsi_device_get(sdev
))
1171 spin_unlock_irqrestore(shost
->host_lock
, flags
);
1175 EXPORT_SYMBOL(scsi_device_lookup
);
1178 * scsi_device_cancel - cancel outstanding IO to this device
1179 * @sdev: Pointer to struct scsi_device
1180 * @recovery: Boolean instructing function to recover device or not.
1183 int scsi_device_cancel(struct scsi_device
*sdev
, int recovery
)
1185 struct scsi_cmnd
*scmd
;
1186 LIST_HEAD(active_list
);
1187 struct list_head
*lh
, *lh_sf
;
1188 unsigned long flags
;
1190 scsi_device_set_state(sdev
, SDEV_CANCEL
);
1192 spin_lock_irqsave(&sdev
->list_lock
, flags
);
1193 list_for_each_entry(scmd
, &sdev
->cmd_list
, list
) {
1194 if (scmd
->request
) {
1196 * If we are unable to remove the timer, it means
1197 * that the command has already timed out or
1200 if (!scsi_delete_timer(scmd
))
1202 list_add_tail(&scmd
->eh_entry
, &active_list
);
1205 spin_unlock_irqrestore(&sdev
->list_lock
, flags
);
1207 if (!list_empty(&active_list
)) {
1208 list_for_each_safe(lh
, lh_sf
, &active_list
) {
1209 scmd
= list_entry(lh
, struct scsi_cmnd
, eh_entry
);
1212 !scsi_eh_scmd_add(scmd
, SCSI_EH_CANCEL_CMD
)) {
1213 scmd
->result
= (DID_ABORT
<< 16);
1214 scsi_finish_command(scmd
);
1221 EXPORT_SYMBOL(scsi_device_cancel
);
1223 MODULE_DESCRIPTION("SCSI core");
1224 MODULE_LICENSE("GPL");
1226 module_param(scsi_logging_level
, int, S_IRUGO
|S_IWUSR
);
1227 MODULE_PARM_DESC(scsi_logging_level
, "a bit mask of logging levels");
1229 static int __init
init_scsi(void)
1233 error
= scsi_init_queue();
1236 error
= scsi_init_procfs();
1239 error
= scsi_init_devinfo();
1241 goto cleanup_procfs
;
1242 error
= scsi_init_hosts();
1244 goto cleanup_devlist
;
1245 error
= scsi_init_sysctl();
1248 error
= scsi_sysfs_register();
1250 goto cleanup_sysctl
;
1252 scsi_netlink_init();
1254 printk(KERN_NOTICE
"SCSI subsystem initialized\n");
1262 scsi_exit_devinfo();
1267 printk(KERN_ERR
"SCSI subsystem failed to initialize, error = %d\n",
1272 static void __exit
exit_scsi(void)
1274 scsi_netlink_exit();
1275 scsi_sysfs_unregister();
1278 scsi_exit_devinfo();
1283 subsys_initcall(init_scsi
);
1284 module_exit(exit_scsi
);