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[linux/fpc-iii.git] / drivers / scsi / scsi.c
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1 /*
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
10 * <drew@colorado.edu>
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
19 * enhancements.
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>
27 * (changed to kmod)
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);
88 #endif
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[] = {
95 "Direct-Access ",
96 "Sequential-Access",
97 "Printer ",
98 "Processor ",
99 "WORM ",
100 "CD-ROM ",
101 "Scanner ",
102 "Optical Device ",
103 "Medium Changer ",
104 "Communications ",
105 "ASC IT8 ",
106 "ASC IT8 ",
107 "RAID ",
108 "Enclosure ",
109 "Direct-Access-RBC",
110 "Optical card ",
111 "Bridge controller",
112 "Object storage ",
113 "Automation/Drive ",
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)
123 if (type == 0x1e)
124 return "Well-known LUN ";
125 if (type == 0x1f)
126 return "No Device ";
127 if (type >= ARRAY_SIZE(scsi_device_types))
128 return "Unknown ";
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;
137 unsigned int users;
138 char *cmd_name;
139 char *sense_name;
140 unsigned int slab_flags;
141 gfp_t gfp_mask;
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
165 * NULL on failure
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);
173 if (!cmd)
174 return NULL;
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);
180 return NULL;
183 return 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.
194 static void
195 scsi_pool_free_command(struct scsi_host_cmd_pool *pool,
196 struct scsi_cmnd *cmd)
198 if (cmd->prot_sdb)
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);
219 if (!cmd)
220 return NULL;
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);
227 return NULL;
231 return 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)) {
247 unsigned long flags;
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);
257 if (cmd) {
258 void *buf, *prot;
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;
270 return cmd;
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))
287 return NULL;
289 cmd = __scsi_get_command(dev->host, gfp_mask);
291 if (likely(cmd != NULL)) {
292 unsigned long flags;
294 cmd->device = dev;
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;
300 } else
301 put_device(&dev->sdev_gendev);
303 return cmd;
305 EXPORT_SYMBOL(scsi_get_command);
308 * __scsi_put_command - Free a struct scsi_cmnd
309 * @shost: dev->host
310 * @cmd: Command to free
311 * @dev: parent scsi device
313 void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd,
314 struct device *dev)
316 unsigned long flags;
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);
322 cmd = NULL;
324 spin_unlock_irqrestore(&shost->free_list_lock, flags);
326 if (likely(cmd != NULL))
327 scsi_pool_free_command(shost->cmd_pool, cmd);
329 put_device(dev);
331 EXPORT_SYMBOL(__scsi_put_command);
334 * scsi_put_command - Free a scsi command block
335 * @cmd: command block to free
337 * Returns: Nothing.
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;
344 unsigned long flags;
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
361 * yet existent.
363 mutex_lock(&host_cmd_pool_mutex);
364 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
365 &scsi_cmd_pool;
366 if (!pool->users) {
367 pool->cmd_slab = kmem_cache_create(pool->cmd_name,
368 sizeof(struct scsi_cmnd), 0,
369 pool->slab_flags, NULL);
370 if (!pool->cmd_slab)
371 goto fail;
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);
378 goto fail;
382 pool->users++;
383 retval = pool;
384 fail:
385 mutex_unlock(&host_cmd_pool_mutex);
386 return retval;
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 :
395 &scsi_cmd_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
399 * the stack trace
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);
427 if (!pool)
428 return NULL;
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
451 * on the pool
453 BUG_ON(!pool);
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.
474 * Returns: Nothing.
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)
487 return -ENOMEM;
490 * Get one backup command for this host.
492 cmd = scsi_host_alloc_command(shost, gfp_mask);
493 if (!cmd) {
494 scsi_put_host_cmd_pool(gfp_mask);
495 shost->cmd_pool = NULL;
496 return -ENOMEM;
498 list_add(&cmd->list, &shost->free_list);
499 return 0;
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)
513 return;
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)
529 unsigned int level;
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);
545 if (level > 1) {
546 scmd_printk(KERN_INFO, cmd, "Send: ");
547 if (level > 2)
548 printk("0x%p ", cmd);
549 printk("\n");
550 scsi_print_command(cmd);
551 if (level > 3) {
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)
564 unsigned int level;
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)) ||
582 (level > 1)) {
583 scmd_printk(KERN_INFO, cmd, "Done: ");
584 if (level > 2)
585 printk("0x%p ", cmd);
587 * Dump truncated values, so we usually fit within
588 * 80 chars.
590 switch (disposition) {
591 case SUCCESS:
592 printk("SUCCESS\n");
593 break;
594 case NEEDS_RETRY:
595 printk("RETRY\n");
596 break;
597 case ADD_TO_MLQUEUE:
598 printk("MLQUEUE\n");
599 break;
600 case FAILED:
601 printk("FAILED\n");
602 break;
603 case TIMEOUT_ERROR:
605 * If called via scsi_times_out.
607 printk("TIMEOUT\n");
608 break;
609 default:
610 printk("UNKNOWN\n");
612 scsi_print_result(cmd);
613 scsi_print_command(cmd);
614 if (status_byte(cmd->result) & CHECK_CONDITION)
615 scsi_print_sense("", cmd);
616 if (level > 3)
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);
624 #endif
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
646 * plugged.
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;
653 int rtn = 0;
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;
663 scsi_done(cmd);
664 /* return 0 (because the command has been processed) */
665 goto out;
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
675 * suspend state.
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)
686 goto out;
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
713 * host).
715 while (--ticks_remaining >= 0)
716 mdelay(1 + 999 / HZ);
717 host->resetting = 0;
720 scsi_log_send(cmd);
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) {
727 SCSI_LOG_MLQUEUE(3,
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);
733 scsi_done(cmd);
734 goto out;
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);
748 scsi_done(cmd);
749 } else {
750 rtn = host->hostt->queuecommand(cmd, scsi_done);
752 spin_unlock_irqrestore(host->host_lock, flags);
753 if (rtn) {
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);
760 SCSI_LOG_MLQUEUE(3,
761 printk("queuecommand : request rejected\n"));
764 out:
765 SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
766 return rtn;
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
795 * @cmd: the command
797 * Description: Pass command off to upper layer for finishing of I/O
798 * request, waking processes that are waiting on results,
799 * etc.
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);
838 if (drv->done)
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).
862 * Returns: Nothing
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)
873 unsigned long flags;
876 * refuse to set tagged depth to an unworkable size
878 if (tags <= 0)
879 return;
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)
895 goto out;
898 sdev->queue_depth = tags;
899 switch (tagged) {
900 case MSG_ORDERED_TAG:
901 sdev->ordered_tags = 1;
902 sdev->simple_tags = 1;
903 break;
904 case MSG_SIMPLE_TAG:
905 sdev->ordered_tags = 0;
906 sdev->simple_tags = 1;
907 break;
908 default:
909 sdev_printk(KERN_WARNING, sdev,
910 "scsi_adjust_queue_depth, bad queue type, "
911 "disabled\n");
912 case 0:
913 sdev->ordered_tags = sdev->simple_tags = 0;
914 sdev->queue_depth = tags;
915 break;
917 out:
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
947 * same event.
949 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
950 return 0;
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;
956 } else {
957 sdev->last_queue_full_count++;
960 if (sdev->last_queue_full_count <= 10)
961 return 0;
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);
965 return -1;
968 if (sdev->ordered_tags)
969 scsi_adjust_queue_depth(sdev, MSG_ORDERED_TAG, depth);
970 else
971 scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
972 return 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)
991 int result;
992 unsigned char cmd[16];
994 cmd[0] = INQUIRY;
995 cmd[1] = 1; /* EVPD */
996 cmd[2] = page;
997 cmd[3] = len >> 8;
998 cmd[4] = len & 0xff;
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);
1007 if (result)
1008 return result;
1010 /* Sanity check that we got the page back that we asked for */
1011 if (buffer[1] != page)
1012 return -EIO;
1014 return 0;
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
1021 * @buf: where to store the VPD
1022 * @buf_len: number of bytes in the VPD buffer area
1024 * SCSI devices may optionally supply Vital Product Data. Each 'page'
1025 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
1026 * If the device supports this VPD page, this routine returns a pointer
1027 * to a buffer containing the data from that page. The caller is
1028 * responsible for calling kfree() on this pointer when it is no longer
1029 * needed. If we cannot retrieve the VPD page this routine returns %NULL.
1031 int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
1032 int buf_len)
1034 int i, result;
1036 /* Ask for all the pages supported by this device */
1037 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len);
1038 if (result)
1039 goto fail;
1041 /* If the user actually wanted this page, we can skip the rest */
1042 if (page == 0)
1043 return -EINVAL;
1045 for (i = 0; i < min((int)buf[3], buf_len - 4); i++)
1046 if (buf[i + 4] == page)
1047 goto found;
1049 if (i < buf[3] && i > buf_len)
1050 /* ran off the end of the buffer, give us benefit of doubt */
1051 goto found;
1052 /* The device claims it doesn't support the requested page */
1053 goto fail;
1055 found:
1056 result = scsi_vpd_inquiry(sdev, buf, page, buf_len);
1057 if (result)
1058 goto fail;
1060 return 0;
1062 fail:
1063 return -EINVAL;
1065 EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
1068 * scsi_device_get - get an additional reference to a scsi_device
1069 * @sdev: device to get a reference to
1071 * Description: Gets a reference to the scsi_device and increments the use count
1072 * of the underlying LLDD module. You must hold host_lock of the
1073 * parent Scsi_Host or already have a reference when calling this.
1075 int scsi_device_get(struct scsi_device *sdev)
1077 if (sdev->sdev_state == SDEV_DEL)
1078 return -ENXIO;
1079 if (!get_device(&sdev->sdev_gendev))
1080 return -ENXIO;
1081 /* We can fail this if we're doing SCSI operations
1082 * from module exit (like cache flush) */
1083 try_module_get(sdev->host->hostt->module);
1085 return 0;
1087 EXPORT_SYMBOL(scsi_device_get);
1090 * scsi_device_put - release a reference to a scsi_device
1091 * @sdev: device to release a reference on.
1093 * Description: Release a reference to the scsi_device and decrements the use
1094 * count of the underlying LLDD module. The device is freed once the last
1095 * user vanishes.
1097 void scsi_device_put(struct scsi_device *sdev)
1099 #ifdef CONFIG_MODULE_UNLOAD
1100 struct module *module = sdev->host->hostt->module;
1102 /* The module refcount will be zero if scsi_device_get()
1103 * was called from a module removal routine */
1104 if (module && module_refcount(module) != 0)
1105 module_put(module);
1106 #endif
1107 put_device(&sdev->sdev_gendev);
1109 EXPORT_SYMBOL(scsi_device_put);
1111 /* helper for shost_for_each_device, see that for documentation */
1112 struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
1113 struct scsi_device *prev)
1115 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
1116 struct scsi_device *next = NULL;
1117 unsigned long flags;
1119 spin_lock_irqsave(shost->host_lock, flags);
1120 while (list->next != &shost->__devices) {
1121 next = list_entry(list->next, struct scsi_device, siblings);
1122 /* skip devices that we can't get a reference to */
1123 if (!scsi_device_get(next))
1124 break;
1125 next = NULL;
1126 list = list->next;
1128 spin_unlock_irqrestore(shost->host_lock, flags);
1130 if (prev)
1131 scsi_device_put(prev);
1132 return next;
1134 EXPORT_SYMBOL(__scsi_iterate_devices);
1137 * starget_for_each_device - helper to walk all devices of a target
1138 * @starget: target whose devices we want to iterate over.
1139 * @data: Opaque passed to each function call.
1140 * @fn: Function to call on each device
1142 * This traverses over each device of @starget. The devices have
1143 * a reference that must be released by scsi_host_put when breaking
1144 * out of the loop.
1146 void starget_for_each_device(struct scsi_target *starget, void *data,
1147 void (*fn)(struct scsi_device *, void *))
1149 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1150 struct scsi_device *sdev;
1152 shost_for_each_device(sdev, shost) {
1153 if ((sdev->channel == starget->channel) &&
1154 (sdev->id == starget->id))
1155 fn(sdev, data);
1158 EXPORT_SYMBOL(starget_for_each_device);
1161 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
1162 * @starget: target whose devices we want to iterate over.
1163 * @data: parameter for callback @fn()
1164 * @fn: callback function that is invoked for each device
1166 * This traverses over each device of @starget. It does _not_
1167 * take a reference on the scsi_device, so the whole loop must be
1168 * protected by shost->host_lock.
1170 * Note: The only reason why drivers would want to use this is because
1171 * they need to access the device list in irq context. Otherwise you
1172 * really want to use starget_for_each_device instead.
1174 void __starget_for_each_device(struct scsi_target *starget, void *data,
1175 void (*fn)(struct scsi_device *, void *))
1177 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1178 struct scsi_device *sdev;
1180 __shost_for_each_device(sdev, shost) {
1181 if ((sdev->channel == starget->channel) &&
1182 (sdev->id == starget->id))
1183 fn(sdev, data);
1186 EXPORT_SYMBOL(__starget_for_each_device);
1189 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
1190 * @starget: SCSI target pointer
1191 * @lun: SCSI Logical Unit Number
1193 * Description: Looks up the scsi_device with the specified @lun for a given
1194 * @starget. The returned scsi_device does not have an additional
1195 * reference. You must hold the host's host_lock over this call and
1196 * any access to the returned scsi_device. A scsi_device in state
1197 * SDEV_DEL is skipped.
1199 * Note: The only reason why drivers should use this is because
1200 * they need to access the device list in irq context. Otherwise you
1201 * really want to use scsi_device_lookup_by_target instead.
1203 struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
1204 uint lun)
1206 struct scsi_device *sdev;
1208 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
1209 if (sdev->sdev_state == SDEV_DEL)
1210 continue;
1211 if (sdev->lun ==lun)
1212 return sdev;
1215 return NULL;
1217 EXPORT_SYMBOL(__scsi_device_lookup_by_target);
1220 * scsi_device_lookup_by_target - find a device given the target
1221 * @starget: SCSI target pointer
1222 * @lun: SCSI Logical Unit Number
1224 * Description: Looks up the scsi_device with the specified @lun for a given
1225 * @starget. The returned scsi_device has an additional reference that
1226 * needs to be released with scsi_device_put once you're done with it.
1228 struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
1229 uint lun)
1231 struct scsi_device *sdev;
1232 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1233 unsigned long flags;
1235 spin_lock_irqsave(shost->host_lock, flags);
1236 sdev = __scsi_device_lookup_by_target(starget, lun);
1237 if (sdev && scsi_device_get(sdev))
1238 sdev = NULL;
1239 spin_unlock_irqrestore(shost->host_lock, flags);
1241 return sdev;
1243 EXPORT_SYMBOL(scsi_device_lookup_by_target);
1246 * __scsi_device_lookup - find a device given the host (UNLOCKED)
1247 * @shost: SCSI host pointer
1248 * @channel: SCSI channel (zero if only one channel)
1249 * @id: SCSI target number (physical unit number)
1250 * @lun: SCSI Logical Unit Number
1252 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1253 * for a given host. The returned scsi_device does not have an additional
1254 * reference. You must hold the host's host_lock over this call and any access
1255 * to the returned scsi_device.
1257 * Note: The only reason why drivers would want to use this is because
1258 * they need to access the device list in irq context. Otherwise you
1259 * really want to use scsi_device_lookup instead.
1261 struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
1262 uint channel, uint id, uint lun)
1264 struct scsi_device *sdev;
1266 list_for_each_entry(sdev, &shost->__devices, siblings) {
1267 if (sdev->channel == channel && sdev->id == id &&
1268 sdev->lun ==lun)
1269 return sdev;
1272 return NULL;
1274 EXPORT_SYMBOL(__scsi_device_lookup);
1277 * scsi_device_lookup - find a device given the host
1278 * @shost: SCSI host pointer
1279 * @channel: SCSI channel (zero if only one channel)
1280 * @id: SCSI target number (physical unit number)
1281 * @lun: SCSI Logical Unit Number
1283 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1284 * for a given host. The returned scsi_device has an additional reference that
1285 * needs to be released with scsi_device_put once you're done with it.
1287 struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1288 uint channel, uint id, uint lun)
1290 struct scsi_device *sdev;
1291 unsigned long flags;
1293 spin_lock_irqsave(shost->host_lock, flags);
1294 sdev = __scsi_device_lookup(shost, channel, id, lun);
1295 if (sdev && scsi_device_get(sdev))
1296 sdev = NULL;
1297 spin_unlock_irqrestore(shost->host_lock, flags);
1299 return sdev;
1301 EXPORT_SYMBOL(scsi_device_lookup);
1303 MODULE_DESCRIPTION("SCSI core");
1304 MODULE_LICENSE("GPL");
1306 module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1307 MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1309 static int __init init_scsi(void)
1311 int error;
1313 error = scsi_init_queue();
1314 if (error)
1315 return error;
1316 error = scsi_init_procfs();
1317 if (error)
1318 goto cleanup_queue;
1319 error = scsi_init_devinfo();
1320 if (error)
1321 goto cleanup_procfs;
1322 error = scsi_init_hosts();
1323 if (error)
1324 goto cleanup_devlist;
1325 error = scsi_init_sysctl();
1326 if (error)
1327 goto cleanup_hosts;
1328 error = scsi_sysfs_register();
1329 if (error)
1330 goto cleanup_sysctl;
1332 scsi_netlink_init();
1334 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1335 return 0;
1337 cleanup_sysctl:
1338 scsi_exit_sysctl();
1339 cleanup_hosts:
1340 scsi_exit_hosts();
1341 cleanup_devlist:
1342 scsi_exit_devinfo();
1343 cleanup_procfs:
1344 scsi_exit_procfs();
1345 cleanup_queue:
1346 scsi_exit_queue();
1347 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1348 -error);
1349 return error;
1352 static void __exit exit_scsi(void)
1354 scsi_netlink_exit();
1355 scsi_sysfs_unregister();
1356 scsi_exit_sysctl();
1357 scsi_exit_hosts();
1358 scsi_exit_devinfo();
1359 scsi_exit_procfs();
1360 scsi_exit_queue();
1363 subsys_initcall(init_scsi);
1364 module_exit(exit_scsi);