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_driver.h>
63
#include <scsi/scsi_eh.h>
64
#include <scsi/scsi_host.h>
65
#include <scsi/scsi_tcq.h>
67
#include "scsi_priv.h"
68
#include "scsi_logging.h"
70
static void scsi_done(struct scsi_cmnd *cmd);
73
* Definitions and constants.
76
#define MIN_RESET_DELAY (2*HZ)
78
/* Do not call reset on error if we just did a reset within 15 sec. */
79
#define MIN_RESET_PERIOD (15*HZ)
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
/* NB: These are exposed through /proc/scsi/scsi and form part of the ABI.
91
* You may not alter any existing entry (although adding new ones is
92
* encouraged once assigned by ANSI/INCITS T10
94
static const char *const scsi_device_types[] = {
117
* scsi_device_type - Return 17 char string indicating device type.
118
* @type: type number to look up
121
const char * scsi_device_type(unsigned type)
124
return "Well-known LUN ";
127
if (type >= ARRAY_SIZE(scsi_device_types))
129
return scsi_device_types[type];
132
EXPORT_SYMBOL(scsi_device_type);
134
struct scsi_host_cmd_pool {
135
struct kmem_cache *cmd_slab;
136
struct kmem_cache *sense_slab;
140
unsigned int slab_flags;
144
static struct scsi_host_cmd_pool scsi_cmd_pool = {
145
.cmd_name = "scsi_cmd_cache",
146
.sense_name = "scsi_sense_cache",
147
.slab_flags = SLAB_HWCACHE_ALIGN,
150
static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
151
.cmd_name = "scsi_cmd_cache(DMA)",
152
.sense_name = "scsi_sense_cache(DMA)",
153
.slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA,
154
.gfp_mask = __GFP_DMA,
157
static DEFINE_MUTEX(host_cmd_pool_mutex);
160
* scsi_pool_alloc_command - internal function to get a fully allocated command
161
* @pool: slab pool to allocate the command from
162
* @gfp_mask: mask for the allocation
164
* Returns a fully allocated command (with the allied sense buffer) or
167
static struct scsi_cmnd *
168
scsi_pool_alloc_command(struct scsi_host_cmd_pool *pool, gfp_t gfp_mask)
170
struct scsi_cmnd *cmd;
172
cmd = kmem_cache_zalloc(pool->cmd_slab, gfp_mask | pool->gfp_mask);
176
cmd->sense_buffer = kmem_cache_alloc(pool->sense_slab,
177
gfp_mask | pool->gfp_mask);
178
if (!cmd->sense_buffer) {
179
kmem_cache_free(pool->cmd_slab, cmd);
187
* scsi_pool_free_command - internal function to release a command
188
* @pool: slab pool to allocate the command from
189
* @cmd: command to release
191
* the command must previously have been allocated by
192
* scsi_pool_alloc_command.
195
scsi_pool_free_command(struct scsi_host_cmd_pool *pool,
196
struct scsi_cmnd *cmd)
199
kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb);
201
kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
202
kmem_cache_free(pool->cmd_slab, cmd);
206
* scsi_host_alloc_command - internal function to allocate command
207
* @shost: SCSI host whose pool to allocate from
208
* @gfp_mask: mask for the allocation
210
* Returns a fully allocated command with sense buffer and protection
211
* data buffer (where applicable) or NULL on failure
213
static struct scsi_cmnd *
214
scsi_host_alloc_command(struct Scsi_Host *shost, gfp_t gfp_mask)
216
struct scsi_cmnd *cmd;
218
cmd = scsi_pool_alloc_command(shost->cmd_pool, gfp_mask);
222
if (scsi_host_get_prot(shost) >= SHOST_DIX_TYPE0_PROTECTION) {
223
cmd->prot_sdb = kmem_cache_zalloc(scsi_sdb_cache, gfp_mask);
225
if (!cmd->prot_sdb) {
226
scsi_pool_free_command(shost->cmd_pool, cmd);
235
* __scsi_get_command - Allocate a struct scsi_cmnd
236
* @shost: host to transmit command
237
* @gfp_mask: allocation mask
239
* Description: allocate a struct scsi_cmd from host's slab, recycling from the
240
* host's free_list if necessary.
242
struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
244
struct scsi_cmnd *cmd = scsi_host_alloc_command(shost, gfp_mask);
246
if (unlikely(!cmd)) {
249
spin_lock_irqsave(&shost->free_list_lock, flags);
250
if (likely(!list_empty(&shost->free_list))) {
251
cmd = list_entry(shost->free_list.next,
252
struct scsi_cmnd, list);
253
list_del_init(&cmd->list);
255
spin_unlock_irqrestore(&shost->free_list_lock, flags);
260
buf = cmd->sense_buffer;
261
prot = cmd->prot_sdb;
263
memset(cmd, 0, sizeof(*cmd));
265
cmd->sense_buffer = buf;
266
cmd->prot_sdb = prot;
272
EXPORT_SYMBOL_GPL(__scsi_get_command);
275
* scsi_get_command - Allocate and setup a scsi command block
276
* @dev: parent scsi device
277
* @gfp_mask: allocator flags
279
* Returns: The allocated scsi command structure.
281
struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
283
struct scsi_cmnd *cmd;
285
/* Bail if we can't get a reference to the device */
286
if (!get_device(&dev->sdev_gendev))
289
cmd = __scsi_get_command(dev->host, gfp_mask);
291
if (likely(cmd != NULL)) {
295
INIT_LIST_HEAD(&cmd->list);
296
spin_lock_irqsave(&dev->list_lock, flags);
297
list_add_tail(&cmd->list, &dev->cmd_list);
298
spin_unlock_irqrestore(&dev->list_lock, flags);
299
cmd->jiffies_at_alloc = jiffies;
301
put_device(&dev->sdev_gendev);
305
EXPORT_SYMBOL(scsi_get_command);
308
* __scsi_put_command - Free a struct scsi_cmnd
310
* @cmd: Command to free
311
* @dev: parent scsi device
313
void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd,
318
/* changing locks here, don't need to restore the irq state */
319
spin_lock_irqsave(&shost->free_list_lock, flags);
320
if (unlikely(list_empty(&shost->free_list))) {
321
list_add(&cmd->list, &shost->free_list);
324
spin_unlock_irqrestore(&shost->free_list_lock, flags);
326
if (likely(cmd != NULL))
327
scsi_pool_free_command(shost->cmd_pool, cmd);
331
EXPORT_SYMBOL(__scsi_put_command);
334
* scsi_put_command - Free a scsi command block
335
* @cmd: command block to free
339
* Notes: The command must not belong to any lists.
341
void scsi_put_command(struct scsi_cmnd *cmd)
343
struct scsi_device *sdev = cmd->device;
346
/* serious error if the command hasn't come from a device list */
347
spin_lock_irqsave(&cmd->device->list_lock, flags);
348
BUG_ON(list_empty(&cmd->list));
349
list_del_init(&cmd->list);
350
spin_unlock_irqrestore(&cmd->device->list_lock, flags);
352
__scsi_put_command(cmd->device->host, cmd, &sdev->sdev_gendev);
354
EXPORT_SYMBOL(scsi_put_command);
356
static struct scsi_host_cmd_pool *scsi_get_host_cmd_pool(gfp_t gfp_mask)
358
struct scsi_host_cmd_pool *retval = NULL, *pool;
360
* Select a command slab for this host and create it if not
363
mutex_lock(&host_cmd_pool_mutex);
364
pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
367
pool->cmd_slab = kmem_cache_create(pool->cmd_name,
368
sizeof(struct scsi_cmnd), 0,
369
pool->slab_flags, NULL);
373
pool->sense_slab = kmem_cache_create(pool->sense_name,
374
SCSI_SENSE_BUFFERSIZE, 0,
375
pool->slab_flags, NULL);
376
if (!pool->sense_slab) {
377
kmem_cache_destroy(pool->cmd_slab);
385
mutex_unlock(&host_cmd_pool_mutex);
389
static void scsi_put_host_cmd_pool(gfp_t gfp_mask)
391
struct scsi_host_cmd_pool *pool;
393
mutex_lock(&host_cmd_pool_mutex);
394
pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
397
* This may happen if a driver has a mismatched get and put
398
* of the command pool; the driver should be implicated in
401
BUG_ON(pool->users == 0);
403
if (!--pool->users) {
404
kmem_cache_destroy(pool->cmd_slab);
405
kmem_cache_destroy(pool->sense_slab);
407
mutex_unlock(&host_cmd_pool_mutex);
411
* scsi_allocate_command - get a fully allocated SCSI command
412
* @gfp_mask: allocation mask
414
* This function is for use outside of the normal host based pools.
415
* It allocates the relevant command and takes an additional reference
416
* on the pool it used. This function *must* be paired with
417
* scsi_free_command which also has the identical mask, otherwise the
418
* free pool counts will eventually go wrong and you'll trigger a bug.
420
* This function should *only* be used by drivers that need a static
421
* command allocation at start of day for internal functions.
423
struct scsi_cmnd *scsi_allocate_command(gfp_t gfp_mask)
425
struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
430
return scsi_pool_alloc_command(pool, gfp_mask);
432
EXPORT_SYMBOL(scsi_allocate_command);
435
* scsi_free_command - free a command allocated by scsi_allocate_command
436
* @gfp_mask: mask used in the original allocation
437
* @cmd: command to free
439
* Note: using the original allocation mask is vital because that's
440
* what determines which command pool we use to free the command. Any
441
* mismatch will cause the system to BUG eventually.
443
void scsi_free_command(gfp_t gfp_mask, struct scsi_cmnd *cmd)
445
struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
448
* this could trigger if the mask to scsi_allocate_command
449
* doesn't match this mask. Otherwise we're guaranteed that this
450
* succeeds because scsi_allocate_command must have taken a reference
455
scsi_pool_free_command(pool, cmd);
457
* scsi_put_host_cmd_pool is called twice; once to release the
458
* reference we took above, and once to release the reference
459
* originally taken by scsi_allocate_command
461
scsi_put_host_cmd_pool(gfp_mask);
462
scsi_put_host_cmd_pool(gfp_mask);
464
EXPORT_SYMBOL(scsi_free_command);
467
* scsi_setup_command_freelist - Setup the command freelist for a scsi host.
468
* @shost: host to allocate the freelist for.
470
* Description: The command freelist protects against system-wide out of memory
471
* deadlock by preallocating one SCSI command structure for each host, so the
472
* system can always write to a swap file on a device associated with that host.
476
int scsi_setup_command_freelist(struct Scsi_Host *shost)
478
struct scsi_cmnd *cmd;
479
const gfp_t gfp_mask = shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL;
481
spin_lock_init(&shost->free_list_lock);
482
INIT_LIST_HEAD(&shost->free_list);
484
shost->cmd_pool = scsi_get_host_cmd_pool(gfp_mask);
486
if (!shost->cmd_pool)
490
* Get one backup command for this host.
492
cmd = scsi_host_alloc_command(shost, gfp_mask);
494
scsi_put_host_cmd_pool(gfp_mask);
495
shost->cmd_pool = NULL;
498
list_add(&cmd->list, &shost->free_list);
503
* scsi_destroy_command_freelist - Release the command freelist for a scsi host.
504
* @shost: host whose freelist is going to be destroyed
506
void scsi_destroy_command_freelist(struct Scsi_Host *shost)
509
* If cmd_pool is NULL the free list was not initialized, so
510
* do not attempt to release resources.
512
if (!shost->cmd_pool)
515
while (!list_empty(&shost->free_list)) {
516
struct scsi_cmnd *cmd;
518
cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
519
list_del_init(&cmd->list);
520
scsi_pool_free_command(shost->cmd_pool, cmd);
522
shost->cmd_pool = NULL;
523
scsi_put_host_cmd_pool(shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL);
526
#ifdef CONFIG_SCSI_LOGGING
527
void scsi_log_send(struct scsi_cmnd *cmd)
532
* If ML QUEUE log level is greater than or equal to:
534
* 1: nothing (match completion)
536
* 2: log opcode + command of all commands
538
* 3: same as 2 plus dump cmd address
540
* 4: same as 3 plus dump extra junk
542
if (unlikely(scsi_logging_level)) {
543
level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
544
SCSI_LOG_MLQUEUE_BITS);
546
scmd_printk(KERN_INFO, cmd, "Send: ");
548
printk("0x%p ", cmd);
550
scsi_print_command(cmd);
552
printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
553
" queuecommand 0x%p\n",
554
scsi_sglist(cmd), scsi_bufflen(cmd),
555
cmd->device->host->hostt->queuecommand);
562
void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
567
* If ML COMPLETE log level is greater than or equal to:
569
* 1: log disposition, result, opcode + command, and conditionally
570
* sense data for failures or non SUCCESS dispositions.
572
* 2: same as 1 but for all command completions.
574
* 3: same as 2 plus dump cmd address
576
* 4: same as 3 plus dump extra junk
578
if (unlikely(scsi_logging_level)) {
579
level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
580
SCSI_LOG_MLCOMPLETE_BITS);
581
if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
583
scmd_printk(KERN_INFO, cmd, "Done: ");
585
printk("0x%p ", cmd);
587
* Dump truncated values, so we usually fit within
590
switch (disposition) {
605
* If called via scsi_times_out.
612
scsi_print_result(cmd);
613
scsi_print_command(cmd);
614
if (status_byte(cmd->result) & CHECK_CONDITION)
615
scsi_print_sense("", cmd);
617
scmd_printk(KERN_INFO, cmd,
618
"scsi host busy %d failed %d\n",
619
cmd->device->host->host_busy,
620
cmd->device->host->host_failed);
627
* scsi_cmd_get_serial - Assign a serial number to a command
628
* @host: the scsi host
629
* @cmd: command to assign serial number to
631
* Description: a serial number identifies a request for error recovery
632
* and debugging purposes. Protected by the Host_Lock of host.
634
static inline void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
636
cmd->serial_number = host->cmd_serial_number++;
637
if (cmd->serial_number == 0)
638
cmd->serial_number = host->cmd_serial_number++;
642
* scsi_dispatch_command - Dispatch a command to the low-level driver.
643
* @cmd: command block we are dispatching.
645
* Return: nonzero return request was rejected and device's queue needs to be
648
int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
650
struct Scsi_Host *host = cmd->device->host;
651
unsigned long flags = 0;
652
unsigned long timeout;
655
atomic_inc(&cmd->device->iorequest_cnt);
657
/* check if the device is still usable */
658
if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
659
/* in SDEV_DEL we error all commands. DID_NO_CONNECT
660
* returns an immediate error upwards, and signals
661
* that the device is no longer present */
662
cmd->result = DID_NO_CONNECT << 16;
664
/* return 0 (because the command has been processed) */
668
/* Check to see if the scsi lld made this device blocked. */
669
if (unlikely(scsi_device_blocked(cmd->device))) {
671
* in blocked state, the command is just put back on
672
* the device queue. The suspend state has already
673
* blocked the queue so future requests should not
674
* occur until the device transitions out of the
678
scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
680
SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
683
* NOTE: rtn is still zero here because we don't need the
684
* queue to be plugged on return (it's already stopped)
690
* If SCSI-2 or lower, store the LUN value in cmnd.
692
if (cmd->device->scsi_level <= SCSI_2 &&
693
cmd->device->scsi_level != SCSI_UNKNOWN) {
694
cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
695
(cmd->device->lun << 5 & 0xe0);
699
* We will wait MIN_RESET_DELAY clock ticks after the last reset so
700
* we can avoid the drive not being ready.
702
timeout = host->last_reset + MIN_RESET_DELAY;
704
if (host->resetting && time_before(jiffies, timeout)) {
705
int ticks_remaining = timeout - jiffies;
707
* NOTE: This may be executed from within an interrupt
708
* handler! This is bad, but for now, it'll do. The irq
709
* level of the interrupt handler has been masked out by the
710
* platform dependent interrupt handling code already, so the
711
* sti() here will not cause another call to the SCSI host's
712
* interrupt handler (assuming there is one irq-level per
715
while (--ticks_remaining >= 0)
716
mdelay(1 + 999 / HZ);
723
* Before we queue this command, check if the command
724
* length exceeds what the host adapter can handle.
726
if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
728
printk("queuecommand : command too long. "
729
"cdb_size=%d host->max_cmd_len=%d\n",
730
cmd->cmd_len, cmd->device->host->max_cmd_len));
731
cmd->result = (DID_ABORT << 16);
737
spin_lock_irqsave(host->host_lock, flags);
739
* AK: unlikely race here: for some reason the timer could
740
* expire before the serial number is set up below.
742
* TODO: kill serial or move to blk layer
744
scsi_cmd_get_serial(host, cmd);
746
if (unlikely(host->shost_state == SHOST_DEL)) {
747
cmd->result = (DID_NO_CONNECT << 16);
750
rtn = host->hostt->queuecommand(cmd, scsi_done);
752
spin_unlock_irqrestore(host->host_lock, flags);
754
if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
755
rtn != SCSI_MLQUEUE_TARGET_BUSY)
756
rtn = SCSI_MLQUEUE_HOST_BUSY;
758
scsi_queue_insert(cmd, rtn);
761
printk("queuecommand : request rejected\n"));
765
SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
770
* scsi_done - Enqueue the finished SCSI command into the done queue.
771
* @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
772
* ownership back to SCSI Core -- i.e. the LLDD has finished with it.
774
* Description: This function is the mid-level's (SCSI Core) interrupt routine,
775
* which regains ownership of the SCSI command (de facto) from a LLDD, and
776
* enqueues the command to the done queue for further processing.
778
* This is the producer of the done queue who enqueues at the tail.
780
* This function is interrupt context safe.
782
static void scsi_done(struct scsi_cmnd *cmd)
784
blk_complete_request(cmd->request);
787
/* Move this to a header if it becomes more generally useful */
788
static struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd)
790
return *(struct scsi_driver **)cmd->request->rq_disk->private_data;
794
* scsi_finish_command - cleanup and pass command back to upper layer
797
* Description: Pass command off to upper layer for finishing of I/O
798
* request, waking processes that are waiting on results,
801
void scsi_finish_command(struct scsi_cmnd *cmd)
803
struct scsi_device *sdev = cmd->device;
804
struct scsi_target *starget = scsi_target(sdev);
805
struct Scsi_Host *shost = sdev->host;
806
struct scsi_driver *drv;
807
unsigned int good_bytes;
809
scsi_device_unbusy(sdev);
812
* Clear the flags which say that the device/host is no longer
813
* capable of accepting new commands. These are set in scsi_queue.c
814
* for both the queue full condition on a device, and for a
815
* host full condition on the host.
817
* XXX(hch): What about locking?
819
shost->host_blocked = 0;
820
starget->target_blocked = 0;
821
sdev->device_blocked = 0;
824
* If we have valid sense information, then some kind of recovery
825
* must have taken place. Make a note of this.
827
if (SCSI_SENSE_VALID(cmd))
828
cmd->result |= (DRIVER_SENSE << 24);
830
SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
831
"Notifying upper driver of completion "
832
"(result %x)\n", cmd->result));
834
good_bytes = scsi_bufflen(cmd);
835
if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
836
int old_good_bytes = good_bytes;
837
drv = scsi_cmd_to_driver(cmd);
839
good_bytes = drv->done(cmd);
841
* USB may not give sense identifying bad sector and
842
* simply return a residue instead, so subtract off the
843
* residue if drv->done() error processing indicates no
844
* change to the completion length.
846
if (good_bytes == old_good_bytes)
847
good_bytes -= scsi_get_resid(cmd);
849
scsi_io_completion(cmd, good_bytes);
851
EXPORT_SYMBOL(scsi_finish_command);
854
* scsi_adjust_queue_depth - Let low level drivers change a device's queue depth
855
* @sdev: SCSI Device in question
856
* @tagged: Do we use tagged queueing (non-0) or do we treat
857
* this device as an untagged device (0)
858
* @tags: Number of tags allowed if tagged queueing enabled,
859
* or number of commands the low level driver can
860
* queue up in non-tagged mode (as per cmd_per_lun).
864
* Lock Status: None held on entry
866
* Notes: Low level drivers may call this at any time and we will do
867
* the right thing depending on whether or not the device is
868
* currently active and whether or not it even has the
869
* command blocks built yet.
871
void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
876
* refuse to set tagged depth to an unworkable size
881
spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
884
* Check to see if the queue is managed by the block layer.
885
* If it is, and we fail to adjust the depth, exit.
887
* Do not resize the tag map if it is a host wide share bqt,
888
* because the size should be the hosts's can_queue. If there
889
* is more IO than the LLD's can_queue (so there are not enuogh
890
* tags) request_fn's host queue ready check will handle it.
892
if (!sdev->host->bqt) {
893
if (blk_queue_tagged(sdev->request_queue) &&
894
blk_queue_resize_tags(sdev->request_queue, tags) != 0)
898
sdev->queue_depth = tags;
900
case MSG_ORDERED_TAG:
901
sdev->ordered_tags = 1;
902
sdev->simple_tags = 1;
905
sdev->ordered_tags = 0;
906
sdev->simple_tags = 1;
909
sdev_printk(KERN_WARNING, sdev,
910
"scsi_adjust_queue_depth, bad queue type, "
913
sdev->ordered_tags = sdev->simple_tags = 0;
914
sdev->queue_depth = tags;
918
spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
920
EXPORT_SYMBOL(scsi_adjust_queue_depth);
923
* scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
924
* @sdev: SCSI Device in question
925
* @depth: Current number of outstanding SCSI commands on this device,
926
* not counting the one returned as QUEUE_FULL.
928
* Description: This function will track successive QUEUE_FULL events on a
929
* specific SCSI device to determine if and when there is a
930
* need to adjust the queue depth on the device.
932
* Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
933
* -1 - Drop back to untagged operation using host->cmd_per_lun
934
* as the untagged command depth
936
* Lock Status: None held on entry
938
* Notes: Low level drivers may call this at any time and we will do
939
* "The Right Thing." We are interrupt context safe.
941
int scsi_track_queue_full(struct scsi_device *sdev, int depth)
945
* Don't let QUEUE_FULLs on the same
946
* jiffies count, they could all be from
949
if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
952
sdev->last_queue_full_time = jiffies;
953
if (sdev->last_queue_full_depth != depth) {
954
sdev->last_queue_full_count = 1;
955
sdev->last_queue_full_depth = depth;
957
sdev->last_queue_full_count++;
960
if (sdev->last_queue_full_count <= 10)
962
if (sdev->last_queue_full_depth < 8) {
963
/* Drop back to untagged */
964
scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
968
if (sdev->ordered_tags)
969
scsi_adjust_queue_depth(sdev, MSG_ORDERED_TAG, depth);
971
scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
974
EXPORT_SYMBOL(scsi_track_queue_full);
977
* scsi_vpd_inquiry - Request a device provide us with a VPD page
978
* @sdev: The device to ask
979
* @buffer: Where to put the result
980
* @page: Which Vital Product Data to return
981
* @len: The length of the buffer
983
* This is an internal helper function. You probably want to use
984
* scsi_get_vpd_page instead.
986
* Returns 0 on success or a negative error number.
988
static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
989
u8 page, unsigned len)
992
unsigned char cmd[16];
995
cmd[1] = 1; /* EVPD */
999
cmd[5] = 0; /* Control byte */
1002
* I'm not convinced we need to try quite this hard to get VPD, but
1003
* all the existing users tried this hard.
1005
result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
1006
len, NULL, 30 * HZ, 3, NULL);
1010
/* Sanity check that we got the page back that we asked for */
1011
if (buffer[1] != page)
1018
* scsi_get_vpd_page - Get Vital Product Data from a SCSI device
1019
* @sdev: The device to ask
1020
* @page: Which Vital Product Data to return
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
unsigned char *scsi_get_vpd_page(struct scsi_device *sdev, u8 page)
1033
const unsigned int init_vpd_len = 255;
1034
unsigned char *buf = kmalloc(init_vpd_len, GFP_KERNEL);
1039
/* Ask for all the pages supported by this device */
1040
result = scsi_vpd_inquiry(sdev, buf, 0, init_vpd_len);
1044
/* If the user actually wanted this page, we can skip the rest */
1048
for (i = 0; i < buf[3]; i++)
1049
if (buf[i + 4] == page)
1051
/* The device claims it doesn't support the requested page */
1055
result = scsi_vpd_inquiry(sdev, buf, page, 255);
1060
* Some pages are longer than 255 bytes. The actual length of
1061
* the page is returned in the header.
1063
len = ((buf[2] << 8) | buf[3]) + 4;
1064
if (len <= init_vpd_len)
1068
buf = kmalloc(len, GFP_KERNEL);
1069
result = scsi_vpd_inquiry(sdev, buf, page, len);
1079
EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
1082
* scsi_device_get - get an additional reference to a scsi_device
1083
* @sdev: device to get a reference to
1085
* Description: Gets a reference to the scsi_device and increments the use count
1086
* of the underlying LLDD module. You must hold host_lock of the
1087
* parent Scsi_Host or already have a reference when calling this.
1089
int scsi_device_get(struct scsi_device *sdev)
1091
if (sdev->sdev_state == SDEV_DEL)
1093
if (!get_device(&sdev->sdev_gendev))
1095
/* We can fail this if we're doing SCSI operations
1096
* from module exit (like cache flush) */
1097
try_module_get(sdev->host->hostt->module);
1101
EXPORT_SYMBOL(scsi_device_get);
1104
* scsi_device_put - release a reference to a scsi_device
1105
* @sdev: device to release a reference on.
1107
* Description: Release a reference to the scsi_device and decrements the use
1108
* count of the underlying LLDD module. The device is freed once the last
1111
void scsi_device_put(struct scsi_device *sdev)
1113
#ifdef CONFIG_MODULE_UNLOAD
1114
struct module *module = sdev->host->hostt->module;
1116
/* The module refcount will be zero if scsi_device_get()
1117
* was called from a module removal routine */
1118
if (module && module_refcount(module) != 0)
1121
put_device(&sdev->sdev_gendev);
1123
EXPORT_SYMBOL(scsi_device_put);
1125
/* helper for shost_for_each_device, see that for documentation */
1126
struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
1127
struct scsi_device *prev)
1129
struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
1130
struct scsi_device *next = NULL;
1131
unsigned long flags;
1133
spin_lock_irqsave(shost->host_lock, flags);
1134
while (list->next != &shost->__devices) {
1135
next = list_entry(list->next, struct scsi_device, siblings);
1136
/* skip devices that we can't get a reference to */
1137
if (!scsi_device_get(next))
1142
spin_unlock_irqrestore(shost->host_lock, flags);
1145
scsi_device_put(prev);
1148
EXPORT_SYMBOL(__scsi_iterate_devices);
1151
* starget_for_each_device - helper to walk all devices of a target
1152
* @starget: target whose devices we want to iterate over.
1153
* @data: Opaque passed to each function call.
1154
* @fn: Function to call on each device
1156
* This traverses over each device of @starget. The devices have
1157
* a reference that must be released by scsi_host_put when breaking
1160
void starget_for_each_device(struct scsi_target *starget, void *data,
1161
void (*fn)(struct scsi_device *, void *))
1163
struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1164
struct scsi_device *sdev;
1166
shost_for_each_device(sdev, shost) {
1167
if ((sdev->channel == starget->channel) &&
1168
(sdev->id == starget->id))
1172
EXPORT_SYMBOL(starget_for_each_device);
1175
* __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
1176
* @starget: target whose devices we want to iterate over.
1177
* @data: parameter for callback @fn()
1178
* @fn: callback function that is invoked for each device
1180
* This traverses over each device of @starget. It does _not_
1181
* take a reference on the scsi_device, so the whole loop must be
1182
* protected by shost->host_lock.
1184
* Note: The only reason why drivers would want to use this is because
1185
* they need to access the device list in irq context. Otherwise you
1186
* really want to use starget_for_each_device instead.
1188
void __starget_for_each_device(struct scsi_target *starget, void *data,
1189
void (*fn)(struct scsi_device *, void *))
1191
struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1192
struct scsi_device *sdev;
1194
__shost_for_each_device(sdev, shost) {
1195
if ((sdev->channel == starget->channel) &&
1196
(sdev->id == starget->id))
1200
EXPORT_SYMBOL(__starget_for_each_device);
1203
* __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
1204
* @starget: SCSI target pointer
1205
* @lun: SCSI Logical Unit Number
1207
* Description: Looks up the scsi_device with the specified @lun for a given
1208
* @starget. The returned scsi_device does not have an additional
1209
* reference. You must hold the host's host_lock over this call and
1210
* any access to the returned scsi_device. A scsi_device in state
1211
* SDEV_DEL is skipped.
1213
* Note: The only reason why drivers should use this is because
1214
* they need to access the device list in irq context. Otherwise you
1215
* really want to use scsi_device_lookup_by_target instead.
1217
struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
1220
struct scsi_device *sdev;
1222
list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
1223
if (sdev->sdev_state == SDEV_DEL)
1225
if (sdev->lun ==lun)
1231
EXPORT_SYMBOL(__scsi_device_lookup_by_target);
1234
* scsi_device_lookup_by_target - find a device given the target
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 has an additional reference that
1240
* needs to be released with scsi_device_put once you're done with it.
1242
struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
1245
struct scsi_device *sdev;
1246
struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1247
unsigned long flags;
1249
spin_lock_irqsave(shost->host_lock, flags);
1250
sdev = __scsi_device_lookup_by_target(starget, lun);
1251
if (sdev && scsi_device_get(sdev))
1253
spin_unlock_irqrestore(shost->host_lock, flags);
1257
EXPORT_SYMBOL(scsi_device_lookup_by_target);
1260
* __scsi_device_lookup - find a device given the host (UNLOCKED)
1261
* @shost: SCSI host pointer
1262
* @channel: SCSI channel (zero if only one channel)
1263
* @id: SCSI target number (physical unit number)
1264
* @lun: SCSI Logical Unit Number
1266
* Description: Looks up the scsi_device with the specified @channel, @id, @lun
1267
* for a given host. The returned scsi_device does not have an additional
1268
* reference. You must hold the host's host_lock over this call and any access
1269
* to the returned scsi_device.
1271
* Note: The only reason why drivers would want to use this is because
1272
* they need to access the device list in irq context. Otherwise you
1273
* really want to use scsi_device_lookup instead.
1275
struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
1276
uint channel, uint id, uint lun)
1278
struct scsi_device *sdev;
1280
list_for_each_entry(sdev, &shost->__devices, siblings) {
1281
if (sdev->channel == channel && sdev->id == id &&
1288
EXPORT_SYMBOL(__scsi_device_lookup);
1291
* scsi_device_lookup - find a device given the host
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 has an additional reference that
1299
* needs to be released with scsi_device_put once you're done with it.
1301
struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1302
uint channel, uint id, uint lun)
1304
struct scsi_device *sdev;
1305
unsigned long flags;
1307
spin_lock_irqsave(shost->host_lock, flags);
1308
sdev = __scsi_device_lookup(shost, channel, id, lun);
1309
if (sdev && scsi_device_get(sdev))
1311
spin_unlock_irqrestore(shost->host_lock, flags);
1315
EXPORT_SYMBOL(scsi_device_lookup);
1317
MODULE_DESCRIPTION("SCSI core");
1318
MODULE_LICENSE("GPL");
1320
module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1321
MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1323
static int __init init_scsi(void)
1327
error = scsi_init_queue();
1330
error = scsi_init_procfs();
1333
error = scsi_init_devinfo();
1335
goto cleanup_procfs;
1336
error = scsi_init_hosts();
1338
goto cleanup_devlist;
1339
error = scsi_init_sysctl();
1342
error = scsi_sysfs_register();
1344
goto cleanup_sysctl;
1346
scsi_netlink_init();
1348
printk(KERN_NOTICE "SCSI subsystem initialized\n");
1356
scsi_exit_devinfo();
1361
printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1366
static void __exit exit_scsi(void)
1368
scsi_netlink_exit();
1369
scsi_sysfs_unregister();
1372
scsi_exit_devinfo();
1377
subsys_initcall(init_scsi);
1378
module_exit(exit_scsi);