TTY: serial, remove dead code from 68328
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / scsi / scsi.c
blob2aeb2e9c4d3bc708d5c12c7a117b021ffc160409
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 #define CREATE_TRACE_POINTS
71 #include <trace/events/scsi.h>
73 static void scsi_done(struct scsi_cmnd *cmd);
76 * Definitions and constants.
79 #define MIN_RESET_DELAY (2*HZ)
81 /* Do not call reset on error if we just did a reset within 15 sec. */
82 #define MIN_RESET_PERIOD (15*HZ)
85 * Note - the initial logging level can be set here to log events at boot time.
86 * After the system is up, you may enable logging via the /proc interface.
88 unsigned int scsi_logging_level;
89 #if defined(CONFIG_SCSI_LOGGING)
90 EXPORT_SYMBOL(scsi_logging_level);
91 #endif
93 /* NB: These are exposed through /proc/scsi/scsi and form part of the ABI.
94 * You may not alter any existing entry (although adding new ones is
95 * encouraged once assigned by ANSI/INCITS T10
97 static const char *const scsi_device_types[] = {
98 "Direct-Access ",
99 "Sequential-Access",
100 "Printer ",
101 "Processor ",
102 "WORM ",
103 "CD-ROM ",
104 "Scanner ",
105 "Optical Device ",
106 "Medium Changer ",
107 "Communications ",
108 "ASC IT8 ",
109 "ASC IT8 ",
110 "RAID ",
111 "Enclosure ",
112 "Direct-Access-RBC",
113 "Optical card ",
114 "Bridge controller",
115 "Object storage ",
116 "Automation/Drive ",
120 * scsi_device_type - Return 17 char string indicating device type.
121 * @type: type number to look up
124 const char * scsi_device_type(unsigned type)
126 if (type == 0x1e)
127 return "Well-known LUN ";
128 if (type == 0x1f)
129 return "No Device ";
130 if (type >= ARRAY_SIZE(scsi_device_types))
131 return "Unknown ";
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;
140 unsigned int users;
141 char *cmd_name;
142 char *sense_name;
143 unsigned int slab_flags;
144 gfp_t gfp_mask;
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
168 * NULL on failure
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);
176 if (!cmd)
177 return NULL;
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);
183 return NULL;
186 return 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.
197 static void
198 scsi_pool_free_command(struct scsi_host_cmd_pool *pool,
199 struct scsi_cmnd *cmd)
201 if (cmd->prot_sdb)
202 kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb);
204 kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
205 kmem_cache_free(pool->cmd_slab, cmd);
209 * scsi_host_alloc_command - internal function to allocate command
210 * @shost: SCSI host whose pool to allocate from
211 * @gfp_mask: mask for the allocation
213 * Returns a fully allocated command with sense buffer and protection
214 * data buffer (where applicable) or NULL on failure
216 static struct scsi_cmnd *
217 scsi_host_alloc_command(struct Scsi_Host *shost, gfp_t gfp_mask)
219 struct scsi_cmnd *cmd;
221 cmd = scsi_pool_alloc_command(shost->cmd_pool, gfp_mask);
222 if (!cmd)
223 return NULL;
225 if (scsi_host_get_prot(shost) >= SHOST_DIX_TYPE0_PROTECTION) {
226 cmd->prot_sdb = kmem_cache_zalloc(scsi_sdb_cache, gfp_mask);
228 if (!cmd->prot_sdb) {
229 scsi_pool_free_command(shost->cmd_pool, cmd);
230 return NULL;
234 return cmd;
238 * __scsi_get_command - Allocate a struct scsi_cmnd
239 * @shost: host to transmit command
240 * @gfp_mask: allocation mask
242 * Description: allocate a struct scsi_cmd from host's slab, recycling from the
243 * host's free_list if necessary.
245 struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
247 struct scsi_cmnd *cmd = scsi_host_alloc_command(shost, gfp_mask);
249 if (unlikely(!cmd)) {
250 unsigned long flags;
252 spin_lock_irqsave(&shost->free_list_lock, flags);
253 if (likely(!list_empty(&shost->free_list))) {
254 cmd = list_entry(shost->free_list.next,
255 struct scsi_cmnd, list);
256 list_del_init(&cmd->list);
258 spin_unlock_irqrestore(&shost->free_list_lock, flags);
260 if (cmd) {
261 void *buf, *prot;
263 buf = cmd->sense_buffer;
264 prot = cmd->prot_sdb;
266 memset(cmd, 0, sizeof(*cmd));
268 cmd->sense_buffer = buf;
269 cmd->prot_sdb = prot;
273 return cmd;
275 EXPORT_SYMBOL_GPL(__scsi_get_command);
278 * scsi_get_command - Allocate and setup a scsi command block
279 * @dev: parent scsi device
280 * @gfp_mask: allocator flags
282 * Returns: The allocated scsi command structure.
284 struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
286 struct scsi_cmnd *cmd;
288 /* Bail if we can't get a reference to the device */
289 if (!get_device(&dev->sdev_gendev))
290 return NULL;
292 cmd = __scsi_get_command(dev->host, gfp_mask);
294 if (likely(cmd != NULL)) {
295 unsigned long flags;
297 cmd->device = dev;
298 INIT_LIST_HEAD(&cmd->list);
299 spin_lock_irqsave(&dev->list_lock, flags);
300 list_add_tail(&cmd->list, &dev->cmd_list);
301 spin_unlock_irqrestore(&dev->list_lock, flags);
302 cmd->jiffies_at_alloc = jiffies;
303 } else
304 put_device(&dev->sdev_gendev);
306 return cmd;
308 EXPORT_SYMBOL(scsi_get_command);
311 * __scsi_put_command - Free a struct scsi_cmnd
312 * @shost: dev->host
313 * @cmd: Command to free
314 * @dev: parent scsi device
316 void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd,
317 struct device *dev)
319 unsigned long flags;
321 /* changing locks here, don't need to restore the irq state */
322 spin_lock_irqsave(&shost->free_list_lock, flags);
323 if (unlikely(list_empty(&shost->free_list))) {
324 list_add(&cmd->list, &shost->free_list);
325 cmd = NULL;
327 spin_unlock_irqrestore(&shost->free_list_lock, flags);
329 if (likely(cmd != NULL))
330 scsi_pool_free_command(shost->cmd_pool, cmd);
332 put_device(dev);
334 EXPORT_SYMBOL(__scsi_put_command);
337 * scsi_put_command - Free a scsi command block
338 * @cmd: command block to free
340 * Returns: Nothing.
342 * Notes: The command must not belong to any lists.
344 void scsi_put_command(struct scsi_cmnd *cmd)
346 struct scsi_device *sdev = cmd->device;
347 unsigned long flags;
349 /* serious error if the command hasn't come from a device list */
350 spin_lock_irqsave(&cmd->device->list_lock, flags);
351 BUG_ON(list_empty(&cmd->list));
352 list_del_init(&cmd->list);
353 spin_unlock_irqrestore(&cmd->device->list_lock, flags);
355 __scsi_put_command(cmd->device->host, cmd, &sdev->sdev_gendev);
357 EXPORT_SYMBOL(scsi_put_command);
359 static struct scsi_host_cmd_pool *scsi_get_host_cmd_pool(gfp_t gfp_mask)
361 struct scsi_host_cmd_pool *retval = NULL, *pool;
363 * Select a command slab for this host and create it if not
364 * yet existent.
366 mutex_lock(&host_cmd_pool_mutex);
367 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
368 &scsi_cmd_pool;
369 if (!pool->users) {
370 pool->cmd_slab = kmem_cache_create(pool->cmd_name,
371 sizeof(struct scsi_cmnd), 0,
372 pool->slab_flags, NULL);
373 if (!pool->cmd_slab)
374 goto fail;
376 pool->sense_slab = kmem_cache_create(pool->sense_name,
377 SCSI_SENSE_BUFFERSIZE, 0,
378 pool->slab_flags, NULL);
379 if (!pool->sense_slab) {
380 kmem_cache_destroy(pool->cmd_slab);
381 goto fail;
385 pool->users++;
386 retval = pool;
387 fail:
388 mutex_unlock(&host_cmd_pool_mutex);
389 return retval;
392 static void scsi_put_host_cmd_pool(gfp_t gfp_mask)
394 struct scsi_host_cmd_pool *pool;
396 mutex_lock(&host_cmd_pool_mutex);
397 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
398 &scsi_cmd_pool;
400 * This may happen if a driver has a mismatched get and put
401 * of the command pool; the driver should be implicated in
402 * the stack trace
404 BUG_ON(pool->users == 0);
406 if (!--pool->users) {
407 kmem_cache_destroy(pool->cmd_slab);
408 kmem_cache_destroy(pool->sense_slab);
410 mutex_unlock(&host_cmd_pool_mutex);
414 * scsi_allocate_command - get a fully allocated SCSI command
415 * @gfp_mask: allocation mask
417 * This function is for use outside of the normal host based pools.
418 * It allocates the relevant command and takes an additional reference
419 * on the pool it used. This function *must* be paired with
420 * scsi_free_command which also has the identical mask, otherwise the
421 * free pool counts will eventually go wrong and you'll trigger a bug.
423 * This function should *only* be used by drivers that need a static
424 * command allocation at start of day for internal functions.
426 struct scsi_cmnd *scsi_allocate_command(gfp_t gfp_mask)
428 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
430 if (!pool)
431 return NULL;
433 return scsi_pool_alloc_command(pool, gfp_mask);
435 EXPORT_SYMBOL(scsi_allocate_command);
438 * scsi_free_command - free a command allocated by scsi_allocate_command
439 * @gfp_mask: mask used in the original allocation
440 * @cmd: command to free
442 * Note: using the original allocation mask is vital because that's
443 * what determines which command pool we use to free the command. Any
444 * mismatch will cause the system to BUG eventually.
446 void scsi_free_command(gfp_t gfp_mask, struct scsi_cmnd *cmd)
448 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
451 * this could trigger if the mask to scsi_allocate_command
452 * doesn't match this mask. Otherwise we're guaranteed that this
453 * succeeds because scsi_allocate_command must have taken a reference
454 * on the pool
456 BUG_ON(!pool);
458 scsi_pool_free_command(pool, cmd);
460 * scsi_put_host_cmd_pool is called twice; once to release the
461 * reference we took above, and once to release the reference
462 * originally taken by scsi_allocate_command
464 scsi_put_host_cmd_pool(gfp_mask);
465 scsi_put_host_cmd_pool(gfp_mask);
467 EXPORT_SYMBOL(scsi_free_command);
470 * scsi_setup_command_freelist - Setup the command freelist for a scsi host.
471 * @shost: host to allocate the freelist for.
473 * Description: The command freelist protects against system-wide out of memory
474 * deadlock by preallocating one SCSI command structure for each host, so the
475 * system can always write to a swap file on a device associated with that host.
477 * Returns: Nothing.
479 int scsi_setup_command_freelist(struct Scsi_Host *shost)
481 struct scsi_cmnd *cmd;
482 const gfp_t gfp_mask = shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL;
484 spin_lock_init(&shost->free_list_lock);
485 INIT_LIST_HEAD(&shost->free_list);
487 shost->cmd_pool = scsi_get_host_cmd_pool(gfp_mask);
489 if (!shost->cmd_pool)
490 return -ENOMEM;
493 * Get one backup command for this host.
495 cmd = scsi_host_alloc_command(shost, gfp_mask);
496 if (!cmd) {
497 scsi_put_host_cmd_pool(gfp_mask);
498 shost->cmd_pool = NULL;
499 return -ENOMEM;
501 list_add(&cmd->list, &shost->free_list);
502 return 0;
506 * scsi_destroy_command_freelist - Release the command freelist for a scsi host.
507 * @shost: host whose freelist is going to be destroyed
509 void scsi_destroy_command_freelist(struct Scsi_Host *shost)
512 * If cmd_pool is NULL the free list was not initialized, so
513 * do not attempt to release resources.
515 if (!shost->cmd_pool)
516 return;
518 while (!list_empty(&shost->free_list)) {
519 struct scsi_cmnd *cmd;
521 cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
522 list_del_init(&cmd->list);
523 scsi_pool_free_command(shost->cmd_pool, cmd);
525 shost->cmd_pool = NULL;
526 scsi_put_host_cmd_pool(shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL);
529 #ifdef CONFIG_SCSI_LOGGING
530 void scsi_log_send(struct scsi_cmnd *cmd)
532 unsigned int level;
535 * If ML QUEUE log level is greater than or equal to:
537 * 1: nothing (match completion)
539 * 2: log opcode + command of all commands
541 * 3: same as 2 plus dump cmd address
543 * 4: same as 3 plus dump extra junk
545 if (unlikely(scsi_logging_level)) {
546 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
547 SCSI_LOG_MLQUEUE_BITS);
548 if (level > 1) {
549 scmd_printk(KERN_INFO, cmd, "Send: ");
550 if (level > 2)
551 printk("0x%p ", cmd);
552 printk("\n");
553 scsi_print_command(cmd);
554 if (level > 3) {
555 printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
556 " queuecommand 0x%p\n",
557 scsi_sglist(cmd), scsi_bufflen(cmd),
558 cmd->device->host->hostt->queuecommand);
565 void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
567 unsigned int level;
570 * If ML COMPLETE log level is greater than or equal to:
572 * 1: log disposition, result, opcode + command, and conditionally
573 * sense data for failures or non SUCCESS dispositions.
575 * 2: same as 1 but for all command completions.
577 * 3: same as 2 plus dump cmd address
579 * 4: same as 3 plus dump extra junk
581 if (unlikely(scsi_logging_level)) {
582 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
583 SCSI_LOG_MLCOMPLETE_BITS);
584 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
585 (level > 1)) {
586 scmd_printk(KERN_INFO, cmd, "Done: ");
587 if (level > 2)
588 printk("0x%p ", cmd);
590 * Dump truncated values, so we usually fit within
591 * 80 chars.
593 switch (disposition) {
594 case SUCCESS:
595 printk("SUCCESS\n");
596 break;
597 case NEEDS_RETRY:
598 printk("RETRY\n");
599 break;
600 case ADD_TO_MLQUEUE:
601 printk("MLQUEUE\n");
602 break;
603 case FAILED:
604 printk("FAILED\n");
605 break;
606 case TIMEOUT_ERROR:
608 * If called via scsi_times_out.
610 printk("TIMEOUT\n");
611 break;
612 default:
613 printk("UNKNOWN\n");
615 scsi_print_result(cmd);
616 scsi_print_command(cmd);
617 if (status_byte(cmd->result) & CHECK_CONDITION)
618 scsi_print_sense("", cmd);
619 if (level > 3)
620 scmd_printk(KERN_INFO, cmd,
621 "scsi host busy %d failed %d\n",
622 cmd->device->host->host_busy,
623 cmd->device->host->host_failed);
627 #endif
630 * scsi_cmd_get_serial - Assign a serial number to a command
631 * @host: the scsi host
632 * @cmd: command to assign serial number to
634 * Description: a serial number identifies a request for error recovery
635 * and debugging purposes. Protected by the Host_Lock of host.
637 void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
639 cmd->serial_number = host->cmd_serial_number++;
640 if (cmd->serial_number == 0)
641 cmd->serial_number = host->cmd_serial_number++;
643 EXPORT_SYMBOL(scsi_cmd_get_serial);
646 * scsi_dispatch_command - Dispatch a command to the low-level driver.
647 * @cmd: command block we are dispatching.
649 * Return: nonzero return request was rejected and device's queue needs to be
650 * plugged.
652 int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
654 struct Scsi_Host *host = cmd->device->host;
655 unsigned long timeout;
656 int rtn = 0;
658 atomic_inc(&cmd->device->iorequest_cnt);
660 /* check if the device is still usable */
661 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
662 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
663 * returns an immediate error upwards, and signals
664 * that the device is no longer present */
665 cmd->result = DID_NO_CONNECT << 16;
666 scsi_done(cmd);
667 /* return 0 (because the command has been processed) */
668 goto out;
671 /* Check to see if the scsi lld made this device blocked. */
672 if (unlikely(scsi_device_blocked(cmd->device))) {
674 * in blocked state, the command is just put back on
675 * the device queue. The suspend state has already
676 * blocked the queue so future requests should not
677 * occur until the device transitions out of the
678 * suspend state.
681 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
683 SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
686 * NOTE: rtn is still zero here because we don't need the
687 * queue to be plugged on return (it's already stopped)
689 goto out;
693 * If SCSI-2 or lower, store the LUN value in cmnd.
695 if (cmd->device->scsi_level <= SCSI_2 &&
696 cmd->device->scsi_level != SCSI_UNKNOWN) {
697 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
698 (cmd->device->lun << 5 & 0xe0);
702 * We will wait MIN_RESET_DELAY clock ticks after the last reset so
703 * we can avoid the drive not being ready.
705 timeout = host->last_reset + MIN_RESET_DELAY;
707 if (host->resetting && time_before(jiffies, timeout)) {
708 int ticks_remaining = timeout - jiffies;
710 * NOTE: This may be executed from within an interrupt
711 * handler! This is bad, but for now, it'll do. The irq
712 * level of the interrupt handler has been masked out by the
713 * platform dependent interrupt handling code already, so the
714 * sti() here will not cause another call to the SCSI host's
715 * interrupt handler (assuming there is one irq-level per
716 * host).
718 while (--ticks_remaining >= 0)
719 mdelay(1 + 999 / HZ);
720 host->resetting = 0;
723 scsi_log_send(cmd);
726 * Before we queue this command, check if the command
727 * length exceeds what the host adapter can handle.
729 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
730 SCSI_LOG_MLQUEUE(3,
731 printk("queuecommand : command too long. "
732 "cdb_size=%d host->max_cmd_len=%d\n",
733 cmd->cmd_len, cmd->device->host->max_cmd_len));
734 cmd->result = (DID_ABORT << 16);
736 scsi_done(cmd);
737 goto out;
740 if (unlikely(host->shost_state == SHOST_DEL)) {
741 cmd->result = (DID_NO_CONNECT << 16);
742 scsi_done(cmd);
743 } else {
744 trace_scsi_dispatch_cmd_start(cmd);
745 cmd->scsi_done = scsi_done;
746 rtn = host->hostt->queuecommand(host, cmd);
749 if (rtn) {
750 trace_scsi_dispatch_cmd_error(cmd, rtn);
751 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
752 rtn != SCSI_MLQUEUE_TARGET_BUSY)
753 rtn = SCSI_MLQUEUE_HOST_BUSY;
755 scsi_queue_insert(cmd, rtn);
757 SCSI_LOG_MLQUEUE(3,
758 printk("queuecommand : request rejected\n"));
761 out:
762 SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
763 return rtn;
767 * scsi_done - Enqueue the finished SCSI command into the done queue.
768 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
769 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
771 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
772 * which regains ownership of the SCSI command (de facto) from a LLDD, and
773 * enqueues the command to the done queue for further processing.
775 * This is the producer of the done queue who enqueues at the tail.
777 * This function is interrupt context safe.
779 static void scsi_done(struct scsi_cmnd *cmd)
781 trace_scsi_dispatch_cmd_done(cmd);
782 blk_complete_request(cmd->request);
785 /* Move this to a header if it becomes more generally useful */
786 static struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd)
788 return *(struct scsi_driver **)cmd->request->rq_disk->private_data;
792 * scsi_finish_command - cleanup and pass command back to upper layer
793 * @cmd: the command
795 * Description: Pass command off to upper layer for finishing of I/O
796 * request, waking processes that are waiting on results,
797 * etc.
799 void scsi_finish_command(struct scsi_cmnd *cmd)
801 struct scsi_device *sdev = cmd->device;
802 struct scsi_target *starget = scsi_target(sdev);
803 struct Scsi_Host *shost = sdev->host;
804 struct scsi_driver *drv;
805 unsigned int good_bytes;
807 scsi_device_unbusy(sdev);
810 * Clear the flags which say that the device/host is no longer
811 * capable of accepting new commands. These are set in scsi_queue.c
812 * for both the queue full condition on a device, and for a
813 * host full condition on the host.
815 * XXX(hch): What about locking?
817 shost->host_blocked = 0;
818 starget->target_blocked = 0;
819 sdev->device_blocked = 0;
822 * If we have valid sense information, then some kind of recovery
823 * must have taken place. Make a note of this.
825 if (SCSI_SENSE_VALID(cmd))
826 cmd->result |= (DRIVER_SENSE << 24);
828 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
829 "Notifying upper driver of completion "
830 "(result %x)\n", cmd->result));
832 good_bytes = scsi_bufflen(cmd);
833 if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
834 int old_good_bytes = good_bytes;
835 drv = scsi_cmd_to_driver(cmd);
836 if (drv->done)
837 good_bytes = drv->done(cmd);
839 * USB may not give sense identifying bad sector and
840 * simply return a residue instead, so subtract off the
841 * residue if drv->done() error processing indicates no
842 * change to the completion length.
844 if (good_bytes == old_good_bytes)
845 good_bytes -= scsi_get_resid(cmd);
847 scsi_io_completion(cmd, good_bytes);
849 EXPORT_SYMBOL(scsi_finish_command);
852 * scsi_adjust_queue_depth - Let low level drivers change a device's queue depth
853 * @sdev: SCSI Device in question
854 * @tagged: Do we use tagged queueing (non-0) or do we treat
855 * this device as an untagged device (0)
856 * @tags: Number of tags allowed if tagged queueing enabled,
857 * or number of commands the low level driver can
858 * queue up in non-tagged mode (as per cmd_per_lun).
860 * Returns: Nothing
862 * Lock Status: None held on entry
864 * Notes: Low level drivers may call this at any time and we will do
865 * the right thing depending on whether or not the device is
866 * currently active and whether or not it even has the
867 * command blocks built yet.
869 void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
871 unsigned long flags;
874 * refuse to set tagged depth to an unworkable size
876 if (tags <= 0)
877 return;
879 spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
882 * Check to see if the queue is managed by the block layer.
883 * If it is, and we fail to adjust the depth, exit.
885 * Do not resize the tag map if it is a host wide share bqt,
886 * because the size should be the hosts's can_queue. If there
887 * is more IO than the LLD's can_queue (so there are not enuogh
888 * tags) request_fn's host queue ready check will handle it.
890 if (!sdev->host->bqt) {
891 if (blk_queue_tagged(sdev->request_queue) &&
892 blk_queue_resize_tags(sdev->request_queue, tags) != 0)
893 goto out;
896 sdev->queue_depth = tags;
897 switch (tagged) {
898 case MSG_ORDERED_TAG:
899 sdev->ordered_tags = 1;
900 sdev->simple_tags = 1;
901 break;
902 case MSG_SIMPLE_TAG:
903 sdev->ordered_tags = 0;
904 sdev->simple_tags = 1;
905 break;
906 default:
907 sdev_printk(KERN_WARNING, sdev,
908 "scsi_adjust_queue_depth, bad queue type, "
909 "disabled\n");
910 case 0:
911 sdev->ordered_tags = sdev->simple_tags = 0;
912 sdev->queue_depth = tags;
913 break;
915 out:
916 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
918 EXPORT_SYMBOL(scsi_adjust_queue_depth);
921 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
922 * @sdev: SCSI Device in question
923 * @depth: Current number of outstanding SCSI commands on this device,
924 * not counting the one returned as QUEUE_FULL.
926 * Description: This function will track successive QUEUE_FULL events on a
927 * specific SCSI device to determine if and when there is a
928 * need to adjust the queue depth on the device.
930 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
931 * -1 - Drop back to untagged operation using host->cmd_per_lun
932 * as the untagged command depth
934 * Lock Status: None held on entry
936 * Notes: Low level drivers may call this at any time and we will do
937 * "The Right Thing." We are interrupt context safe.
939 int scsi_track_queue_full(struct scsi_device *sdev, int depth)
943 * Don't let QUEUE_FULLs on the same
944 * jiffies count, they could all be from
945 * same event.
947 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
948 return 0;
950 sdev->last_queue_full_time = jiffies;
951 if (sdev->last_queue_full_depth != depth) {
952 sdev->last_queue_full_count = 1;
953 sdev->last_queue_full_depth = depth;
954 } else {
955 sdev->last_queue_full_count++;
958 if (sdev->last_queue_full_count <= 10)
959 return 0;
960 if (sdev->last_queue_full_depth < 8) {
961 /* Drop back to untagged */
962 scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
963 return -1;
966 if (sdev->ordered_tags)
967 scsi_adjust_queue_depth(sdev, MSG_ORDERED_TAG, depth);
968 else
969 scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
970 return depth;
972 EXPORT_SYMBOL(scsi_track_queue_full);
975 * scsi_vpd_inquiry - Request a device provide us with a VPD page
976 * @sdev: The device to ask
977 * @buffer: Where to put the result
978 * @page: Which Vital Product Data to return
979 * @len: The length of the buffer
981 * This is an internal helper function. You probably want to use
982 * scsi_get_vpd_page instead.
984 * Returns 0 on success or a negative error number.
986 static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
987 u8 page, unsigned len)
989 int result;
990 unsigned char cmd[16];
992 cmd[0] = INQUIRY;
993 cmd[1] = 1; /* EVPD */
994 cmd[2] = page;
995 cmd[3] = len >> 8;
996 cmd[4] = len & 0xff;
997 cmd[5] = 0; /* Control byte */
1000 * I'm not convinced we need to try quite this hard to get VPD, but
1001 * all the existing users tried this hard.
1003 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
1004 len, NULL, 30 * HZ, 3, NULL);
1005 if (result)
1006 return result;
1008 /* Sanity check that we got the page back that we asked for */
1009 if (buffer[1] != page)
1010 return -EIO;
1012 return 0;
1016 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
1017 * @sdev: The device to ask
1018 * @page: Which Vital Product Data to return
1019 * @buf: where to store the VPD
1020 * @buf_len: number of bytes in the VPD buffer area
1022 * SCSI devices may optionally supply Vital Product Data. Each 'page'
1023 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
1024 * If the device supports this VPD page, this routine returns a pointer
1025 * to a buffer containing the data from that page. The caller is
1026 * responsible for calling kfree() on this pointer when it is no longer
1027 * needed. If we cannot retrieve the VPD page this routine returns %NULL.
1029 int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
1030 int buf_len)
1032 int i, result;
1034 /* Ask for all the pages supported by this device */
1035 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len);
1036 if (result)
1037 goto fail;
1039 /* If the user actually wanted this page, we can skip the rest */
1040 if (page == 0)
1041 return 0;
1043 for (i = 0; i < min((int)buf[3], buf_len - 4); i++)
1044 if (buf[i + 4] == page)
1045 goto found;
1047 if (i < buf[3] && i >= buf_len - 4)
1048 /* ran off the end of the buffer, give us benefit of doubt */
1049 goto found;
1050 /* The device claims it doesn't support the requested page */
1051 goto fail;
1053 found:
1054 result = scsi_vpd_inquiry(sdev, buf, page, buf_len);
1055 if (result)
1056 goto fail;
1058 return 0;
1060 fail:
1061 return -EINVAL;
1063 EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
1066 * scsi_device_get - get an additional reference to a scsi_device
1067 * @sdev: device to get a reference to
1069 * Description: Gets a reference to the scsi_device and increments the use count
1070 * of the underlying LLDD module. You must hold host_lock of the
1071 * parent Scsi_Host or already have a reference when calling this.
1073 int scsi_device_get(struct scsi_device *sdev)
1075 if (sdev->sdev_state == SDEV_DEL)
1076 return -ENXIO;
1077 if (!get_device(&sdev->sdev_gendev))
1078 return -ENXIO;
1079 /* We can fail this if we're doing SCSI operations
1080 * from module exit (like cache flush) */
1081 try_module_get(sdev->host->hostt->module);
1083 return 0;
1085 EXPORT_SYMBOL(scsi_device_get);
1088 * scsi_device_put - release a reference to a scsi_device
1089 * @sdev: device to release a reference on.
1091 * Description: Release a reference to the scsi_device and decrements the use
1092 * count of the underlying LLDD module. The device is freed once the last
1093 * user vanishes.
1095 void scsi_device_put(struct scsi_device *sdev)
1097 #ifdef CONFIG_MODULE_UNLOAD
1098 struct module *module = sdev->host->hostt->module;
1100 /* The module refcount will be zero if scsi_device_get()
1101 * was called from a module removal routine */
1102 if (module && module_refcount(module) != 0)
1103 module_put(module);
1104 #endif
1105 put_device(&sdev->sdev_gendev);
1107 EXPORT_SYMBOL(scsi_device_put);
1109 /* helper for shost_for_each_device, see that for documentation */
1110 struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
1111 struct scsi_device *prev)
1113 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
1114 struct scsi_device *next = NULL;
1115 unsigned long flags;
1117 spin_lock_irqsave(shost->host_lock, flags);
1118 while (list->next != &shost->__devices) {
1119 next = list_entry(list->next, struct scsi_device, siblings);
1120 /* skip devices that we can't get a reference to */
1121 if (!scsi_device_get(next))
1122 break;
1123 next = NULL;
1124 list = list->next;
1126 spin_unlock_irqrestore(shost->host_lock, flags);
1128 if (prev)
1129 scsi_device_put(prev);
1130 return next;
1132 EXPORT_SYMBOL(__scsi_iterate_devices);
1135 * starget_for_each_device - helper to walk all devices of a target
1136 * @starget: target whose devices we want to iterate over.
1137 * @data: Opaque passed to each function call.
1138 * @fn: Function to call on each device
1140 * This traverses over each device of @starget. The devices have
1141 * a reference that must be released by scsi_host_put when breaking
1142 * out of the loop.
1144 void starget_for_each_device(struct scsi_target *starget, void *data,
1145 void (*fn)(struct scsi_device *, void *))
1147 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1148 struct scsi_device *sdev;
1150 shost_for_each_device(sdev, shost) {
1151 if ((sdev->channel == starget->channel) &&
1152 (sdev->id == starget->id))
1153 fn(sdev, data);
1156 EXPORT_SYMBOL(starget_for_each_device);
1159 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
1160 * @starget: target whose devices we want to iterate over.
1161 * @data: parameter for callback @fn()
1162 * @fn: callback function that is invoked for each device
1164 * This traverses over each device of @starget. It does _not_
1165 * take a reference on the scsi_device, so the whole loop must be
1166 * protected by shost->host_lock.
1168 * Note: The only reason why drivers would want to use this is because
1169 * they need to access the device list in irq context. Otherwise you
1170 * really want to use starget_for_each_device instead.
1172 void __starget_for_each_device(struct scsi_target *starget, void *data,
1173 void (*fn)(struct scsi_device *, void *))
1175 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1176 struct scsi_device *sdev;
1178 __shost_for_each_device(sdev, shost) {
1179 if ((sdev->channel == starget->channel) &&
1180 (sdev->id == starget->id))
1181 fn(sdev, data);
1184 EXPORT_SYMBOL(__starget_for_each_device);
1187 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
1188 * @starget: SCSI target pointer
1189 * @lun: SCSI Logical Unit Number
1191 * Description: Looks up the scsi_device with the specified @lun for a given
1192 * @starget. The returned scsi_device does not have an additional
1193 * reference. You must hold the host's host_lock over this call and
1194 * any access to the returned scsi_device. A scsi_device in state
1195 * SDEV_DEL is skipped.
1197 * Note: The only reason why drivers should use this is because
1198 * they need to access the device list in irq context. Otherwise you
1199 * really want to use scsi_device_lookup_by_target instead.
1201 struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
1202 uint lun)
1204 struct scsi_device *sdev;
1206 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
1207 if (sdev->sdev_state == SDEV_DEL)
1208 continue;
1209 if (sdev->lun ==lun)
1210 return sdev;
1213 return NULL;
1215 EXPORT_SYMBOL(__scsi_device_lookup_by_target);
1218 * scsi_device_lookup_by_target - find a device given the target
1219 * @starget: SCSI target pointer
1220 * @lun: SCSI Logical Unit Number
1222 * Description: Looks up the scsi_device with the specified @lun for a given
1223 * @starget. The returned scsi_device has an additional reference that
1224 * needs to be released with scsi_device_put once you're done with it.
1226 struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
1227 uint lun)
1229 struct scsi_device *sdev;
1230 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1231 unsigned long flags;
1233 spin_lock_irqsave(shost->host_lock, flags);
1234 sdev = __scsi_device_lookup_by_target(starget, lun);
1235 if (sdev && scsi_device_get(sdev))
1236 sdev = NULL;
1237 spin_unlock_irqrestore(shost->host_lock, flags);
1239 return sdev;
1241 EXPORT_SYMBOL(scsi_device_lookup_by_target);
1244 * __scsi_device_lookup - find a device given the host (UNLOCKED)
1245 * @shost: SCSI host pointer
1246 * @channel: SCSI channel (zero if only one channel)
1247 * @id: SCSI target number (physical unit number)
1248 * @lun: SCSI Logical Unit Number
1250 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1251 * for a given host. The returned scsi_device does not have an additional
1252 * reference. You must hold the host's host_lock over this call and any access
1253 * to the returned scsi_device.
1255 * Note: The only reason why drivers would want to use this is because
1256 * they need to access the device list in irq context. Otherwise you
1257 * really want to use scsi_device_lookup instead.
1259 struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
1260 uint channel, uint id, uint lun)
1262 struct scsi_device *sdev;
1264 list_for_each_entry(sdev, &shost->__devices, siblings) {
1265 if (sdev->channel == channel && sdev->id == id &&
1266 sdev->lun ==lun)
1267 return sdev;
1270 return NULL;
1272 EXPORT_SYMBOL(__scsi_device_lookup);
1275 * scsi_device_lookup - find a device given the host
1276 * @shost: SCSI host pointer
1277 * @channel: SCSI channel (zero if only one channel)
1278 * @id: SCSI target number (physical unit number)
1279 * @lun: SCSI Logical Unit Number
1281 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1282 * for a given host. The returned scsi_device has an additional reference that
1283 * needs to be released with scsi_device_put once you're done with it.
1285 struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1286 uint channel, uint id, uint lun)
1288 struct scsi_device *sdev;
1289 unsigned long flags;
1291 spin_lock_irqsave(shost->host_lock, flags);
1292 sdev = __scsi_device_lookup(shost, channel, id, lun);
1293 if (sdev && scsi_device_get(sdev))
1294 sdev = NULL;
1295 spin_unlock_irqrestore(shost->host_lock, flags);
1297 return sdev;
1299 EXPORT_SYMBOL(scsi_device_lookup);
1301 MODULE_DESCRIPTION("SCSI core");
1302 MODULE_LICENSE("GPL");
1304 module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1305 MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1307 static int __init init_scsi(void)
1309 int error;
1311 error = scsi_init_queue();
1312 if (error)
1313 return error;
1314 error = scsi_init_procfs();
1315 if (error)
1316 goto cleanup_queue;
1317 error = scsi_init_devinfo();
1318 if (error)
1319 goto cleanup_procfs;
1320 error = scsi_init_hosts();
1321 if (error)
1322 goto cleanup_devlist;
1323 error = scsi_init_sysctl();
1324 if (error)
1325 goto cleanup_hosts;
1326 error = scsi_sysfs_register();
1327 if (error)
1328 goto cleanup_sysctl;
1330 scsi_netlink_init();
1332 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1333 return 0;
1335 cleanup_sysctl:
1336 scsi_exit_sysctl();
1337 cleanup_hosts:
1338 scsi_exit_hosts();
1339 cleanup_devlist:
1340 scsi_exit_devinfo();
1341 cleanup_procfs:
1342 scsi_exit_procfs();
1343 cleanup_queue:
1344 scsi_exit_queue();
1345 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1346 -error);
1347 return error;
1350 static void __exit exit_scsi(void)
1352 scsi_netlink_exit();
1353 scsi_sysfs_unregister();
1354 scsi_exit_sysctl();
1355 scsi_exit_hosts();
1356 scsi_exit_devinfo();
1357 scsi_exit_procfs();
1358 scsi_exit_queue();
1361 subsys_initcall(init_scsi);
1362 module_exit(exit_scsi);