Loading...
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
5 *
6 * generic mid-level SCSI driver
7 * Initial versions: Drew Eckhardt
8 * Subsequent revisions: Eric Youngdale
9 *
10 * <drew@colorado.edu>
11 *
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>
16 *
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.
20 *
21 * Native multichannel, wide scsi, /proc/scsi and hot plugging
22 * support added by Michael Neuffer <mike@i-connect.net>
23 *
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)
28 *
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>
32 *
33 * Converted cli() code to spinlocks, Ingo Molnar
34 *
35 * Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
36 *
37 * out_of_space hacks, D. Gilbert (dpg) 990608
38 */
39
40#include <linux/module.h>
41#include <linux/moduleparam.h>
42#include <linux/kernel.h>
43#include <linux/timer.h>
44#include <linux/string.h>
45#include <linux/slab.h>
46#include <linux/blkdev.h>
47#include <linux/delay.h>
48#include <linux/init.h>
49#include <linux/completion.h>
50#include <linux/unistd.h>
51#include <linux/spinlock.h>
52#include <linux/kmod.h>
53#include <linux/interrupt.h>
54#include <linux/notifier.h>
55#include <linux/cpu.h>
56#include <linux/mutex.h>
57#include <linux/async.h>
58#include <asm/unaligned.h>
59
60#include <scsi/scsi.h>
61#include <scsi/scsi_cmnd.h>
62#include <scsi/scsi_dbg.h>
63#include <scsi/scsi_device.h>
64#include <scsi/scsi_driver.h>
65#include <scsi/scsi_eh.h>
66#include <scsi/scsi_host.h>
67#include <scsi/scsi_tcq.h>
68
69#include "scsi_priv.h"
70#include "scsi_logging.h"
71
72#define CREATE_TRACE_POINTS
73#include <trace/events/scsi.h>
74
75static void scsi_done(struct scsi_cmnd *cmd);
76
77/*
78 * Definitions and constants.
79 */
80
81/*
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.
84 */
85unsigned int scsi_logging_level;
86#if defined(CONFIG_SCSI_LOGGING)
87EXPORT_SYMBOL(scsi_logging_level);
88#endif
89
90/* sd, scsi core and power management need to coordinate flushing async actions */
91ASYNC_DOMAIN(scsi_sd_probe_domain);
92EXPORT_SYMBOL(scsi_sd_probe_domain);
93
94/*
95 * Separate domain (from scsi_sd_probe_domain) to maximize the benefit of
96 * asynchronous system resume operations. It is marked 'exclusive' to avoid
97 * being included in the async_synchronize_full() that is invoked by
98 * dpm_resume()
99 */
100ASYNC_DOMAIN_EXCLUSIVE(scsi_sd_pm_domain);
101EXPORT_SYMBOL(scsi_sd_pm_domain);
102
103/* NB: These are exposed through /proc/scsi/scsi and form part of the ABI.
104 * You may not alter any existing entry (although adding new ones is
105 * encouraged once assigned by ANSI/INCITS T10
106 */
107static const char *const scsi_device_types[] = {
108 "Direct-Access ",
109 "Sequential-Access",
110 "Printer ",
111 "Processor ",
112 "WORM ",
113 "CD-ROM ",
114 "Scanner ",
115 "Optical Device ",
116 "Medium Changer ",
117 "Communications ",
118 "ASC IT8 ",
119 "ASC IT8 ",
120 "RAID ",
121 "Enclosure ",
122 "Direct-Access-RBC",
123 "Optical card ",
124 "Bridge controller",
125 "Object storage ",
126 "Automation/Drive ",
127};
128
129/**
130 * scsi_device_type - Return 17 char string indicating device type.
131 * @type: type number to look up
132 */
133
134const char * scsi_device_type(unsigned type)
135{
136 if (type == 0x1e)
137 return "Well-known LUN ";
138 if (type == 0x1f)
139 return "No Device ";
140 if (type >= ARRAY_SIZE(scsi_device_types))
141 return "Unknown ";
142 return scsi_device_types[type];
143}
144
145EXPORT_SYMBOL(scsi_device_type);
146
147struct scsi_host_cmd_pool {
148 struct kmem_cache *cmd_slab;
149 struct kmem_cache *sense_slab;
150 unsigned int users;
151 char *cmd_name;
152 char *sense_name;
153 unsigned int slab_flags;
154 gfp_t gfp_mask;
155};
156
157static struct scsi_host_cmd_pool scsi_cmd_pool = {
158 .cmd_name = "scsi_cmd_cache",
159 .sense_name = "scsi_sense_cache",
160 .slab_flags = SLAB_HWCACHE_ALIGN,
161};
162
163static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
164 .cmd_name = "scsi_cmd_cache(DMA)",
165 .sense_name = "scsi_sense_cache(DMA)",
166 .slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA,
167 .gfp_mask = __GFP_DMA,
168};
169
170static DEFINE_MUTEX(host_cmd_pool_mutex);
171
172/**
173 * scsi_host_free_command - internal function to release a command
174 * @shost: host to free the command for
175 * @cmd: command to release
176 *
177 * the command must previously have been allocated by
178 * scsi_host_alloc_command.
179 */
180static void
181scsi_host_free_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
182{
183 struct scsi_host_cmd_pool *pool = shost->cmd_pool;
184
185 if (cmd->prot_sdb)
186 kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb);
187 kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
188 kmem_cache_free(pool->cmd_slab, cmd);
189}
190
191/**
192 * scsi_host_alloc_command - internal function to allocate command
193 * @shost: SCSI host whose pool to allocate from
194 * @gfp_mask: mask for the allocation
195 *
196 * Returns a fully allocated command with sense buffer and protection
197 * data buffer (where applicable) or NULL on failure
198 */
199static struct scsi_cmnd *
200scsi_host_alloc_command(struct Scsi_Host *shost, gfp_t gfp_mask)
201{
202 struct scsi_host_cmd_pool *pool = shost->cmd_pool;
203 struct scsi_cmnd *cmd;
204
205 cmd = kmem_cache_zalloc(pool->cmd_slab, gfp_mask | pool->gfp_mask);
206 if (!cmd)
207 goto fail;
208
209 cmd->sense_buffer = kmem_cache_alloc(pool->sense_slab,
210 gfp_mask | pool->gfp_mask);
211 if (!cmd->sense_buffer)
212 goto fail_free_cmd;
213
214 if (scsi_host_get_prot(shost) >= SHOST_DIX_TYPE0_PROTECTION) {
215 cmd->prot_sdb = kmem_cache_zalloc(scsi_sdb_cache, gfp_mask);
216 if (!cmd->prot_sdb)
217 goto fail_free_sense;
218 }
219
220 return cmd;
221
222fail_free_sense:
223 kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
224fail_free_cmd:
225 kmem_cache_free(pool->cmd_slab, cmd);
226fail:
227 return NULL;
228}
229
230/**
231 * __scsi_get_command - Allocate a struct scsi_cmnd
232 * @shost: host to transmit command
233 * @gfp_mask: allocation mask
234 *
235 * Description: allocate a struct scsi_cmd from host's slab, recycling from the
236 * host's free_list if necessary.
237 */
238struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
239{
240 struct scsi_cmnd *cmd = scsi_host_alloc_command(shost, gfp_mask);
241
242 if (unlikely(!cmd)) {
243 unsigned long flags;
244
245 spin_lock_irqsave(&shost->free_list_lock, flags);
246 if (likely(!list_empty(&shost->free_list))) {
247 cmd = list_entry(shost->free_list.next,
248 struct scsi_cmnd, list);
249 list_del_init(&cmd->list);
250 }
251 spin_unlock_irqrestore(&shost->free_list_lock, flags);
252
253 if (cmd) {
254 void *buf, *prot;
255
256 buf = cmd->sense_buffer;
257 prot = cmd->prot_sdb;
258
259 memset(cmd, 0, sizeof(*cmd));
260
261 cmd->sense_buffer = buf;
262 cmd->prot_sdb = prot;
263 }
264 }
265
266 return cmd;
267}
268EXPORT_SYMBOL_GPL(__scsi_get_command);
269
270/**
271 * scsi_get_command - Allocate and setup a scsi command block
272 * @dev: parent scsi device
273 * @gfp_mask: allocator flags
274 *
275 * Returns: The allocated scsi command structure.
276 */
277struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
278{
279 struct scsi_cmnd *cmd = __scsi_get_command(dev->host, gfp_mask);
280 unsigned long flags;
281
282 if (unlikely(cmd == NULL))
283 return NULL;
284
285 cmd->device = dev;
286 INIT_LIST_HEAD(&cmd->list);
287 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
288 spin_lock_irqsave(&dev->list_lock, flags);
289 list_add_tail(&cmd->list, &dev->cmd_list);
290 spin_unlock_irqrestore(&dev->list_lock, flags);
291 cmd->jiffies_at_alloc = jiffies;
292 return cmd;
293}
294EXPORT_SYMBOL(scsi_get_command);
295
296/**
297 * __scsi_put_command - Free a struct scsi_cmnd
298 * @shost: dev->host
299 * @cmd: Command to free
300 */
301void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
302{
303 unsigned long flags;
304
305 if (unlikely(list_empty(&shost->free_list))) {
306 spin_lock_irqsave(&shost->free_list_lock, flags);
307 if (list_empty(&shost->free_list)) {
308 list_add(&cmd->list, &shost->free_list);
309 cmd = NULL;
310 }
311 spin_unlock_irqrestore(&shost->free_list_lock, flags);
312 }
313
314 if (likely(cmd != NULL))
315 scsi_host_free_command(shost, cmd);
316}
317EXPORT_SYMBOL(__scsi_put_command);
318
319/**
320 * scsi_put_command - Free a scsi command block
321 * @cmd: command block to free
322 *
323 * Returns: Nothing.
324 *
325 * Notes: The command must not belong to any lists.
326 */
327void scsi_put_command(struct scsi_cmnd *cmd)
328{
329 unsigned long flags;
330
331 /* serious error if the command hasn't come from a device list */
332 spin_lock_irqsave(&cmd->device->list_lock, flags);
333 BUG_ON(list_empty(&cmd->list));
334 list_del_init(&cmd->list);
335 spin_unlock_irqrestore(&cmd->device->list_lock, flags);
336
337 cancel_delayed_work(&cmd->abort_work);
338
339 __scsi_put_command(cmd->device->host, cmd);
340}
341EXPORT_SYMBOL(scsi_put_command);
342
343static struct scsi_host_cmd_pool *
344scsi_find_host_cmd_pool(struct Scsi_Host *shost)
345{
346 if (shost->hostt->cmd_size)
347 return shost->hostt->cmd_pool;
348 if (shost->unchecked_isa_dma)
349 return &scsi_cmd_dma_pool;
350 return &scsi_cmd_pool;
351}
352
353static void
354scsi_free_host_cmd_pool(struct scsi_host_cmd_pool *pool)
355{
356 kfree(pool->sense_name);
357 kfree(pool->cmd_name);
358 kfree(pool);
359}
360
361static struct scsi_host_cmd_pool *
362scsi_alloc_host_cmd_pool(struct Scsi_Host *shost)
363{
364 struct scsi_host_template *hostt = shost->hostt;
365 struct scsi_host_cmd_pool *pool;
366
367 pool = kzalloc(sizeof(*pool), GFP_KERNEL);
368 if (!pool)
369 return NULL;
370
371 pool->cmd_name = kasprintf(GFP_KERNEL, "%s_cmd", hostt->name);
372 pool->sense_name = kasprintf(GFP_KERNEL, "%s_sense", hostt->name);
373 if (!pool->cmd_name || !pool->sense_name) {
374 scsi_free_host_cmd_pool(pool);
375 return NULL;
376 }
377
378 pool->slab_flags = SLAB_HWCACHE_ALIGN;
379 if (shost->unchecked_isa_dma) {
380 pool->slab_flags |= SLAB_CACHE_DMA;
381 pool->gfp_mask = __GFP_DMA;
382 }
383 return pool;
384}
385
386static struct scsi_host_cmd_pool *
387scsi_get_host_cmd_pool(struct Scsi_Host *shost)
388{
389 struct scsi_host_template *hostt = shost->hostt;
390 struct scsi_host_cmd_pool *retval = NULL, *pool;
391 size_t cmd_size = sizeof(struct scsi_cmnd) + hostt->cmd_size;
392
393 /*
394 * Select a command slab for this host and create it if not
395 * yet existent.
396 */
397 mutex_lock(&host_cmd_pool_mutex);
398 pool = scsi_find_host_cmd_pool(shost);
399 if (!pool) {
400 pool = scsi_alloc_host_cmd_pool(shost);
401 if (!pool)
402 goto out;
403 }
404
405 if (!pool->users) {
406 pool->cmd_slab = kmem_cache_create(pool->cmd_name, cmd_size, 0,
407 pool->slab_flags, NULL);
408 if (!pool->cmd_slab)
409 goto out_free_pool;
410
411 pool->sense_slab = kmem_cache_create(pool->sense_name,
412 SCSI_SENSE_BUFFERSIZE, 0,
413 pool->slab_flags, NULL);
414 if (!pool->sense_slab)
415 goto out_free_slab;
416 }
417
418 pool->users++;
419 retval = pool;
420out:
421 mutex_unlock(&host_cmd_pool_mutex);
422 return retval;
423
424out_free_slab:
425 kmem_cache_destroy(pool->cmd_slab);
426out_free_pool:
427 if (hostt->cmd_size)
428 scsi_free_host_cmd_pool(pool);
429 goto out;
430}
431
432static void scsi_put_host_cmd_pool(struct Scsi_Host *shost)
433{
434 struct scsi_host_template *hostt = shost->hostt;
435 struct scsi_host_cmd_pool *pool;
436
437 mutex_lock(&host_cmd_pool_mutex);
438 pool = scsi_find_host_cmd_pool(shost);
439
440 /*
441 * This may happen if a driver has a mismatched get and put
442 * of the command pool; the driver should be implicated in
443 * the stack trace
444 */
445 BUG_ON(pool->users == 0);
446
447 if (!--pool->users) {
448 kmem_cache_destroy(pool->cmd_slab);
449 kmem_cache_destroy(pool->sense_slab);
450 if (hostt->cmd_size)
451 scsi_free_host_cmd_pool(pool);
452 }
453 mutex_unlock(&host_cmd_pool_mutex);
454}
455
456/**
457 * scsi_setup_command_freelist - Setup the command freelist for a scsi host.
458 * @shost: host to allocate the freelist for.
459 *
460 * Description: The command freelist protects against system-wide out of memory
461 * deadlock by preallocating one SCSI command structure for each host, so the
462 * system can always write to a swap file on a device associated with that host.
463 *
464 * Returns: Nothing.
465 */
466int scsi_setup_command_freelist(struct Scsi_Host *shost)
467{
468 const gfp_t gfp_mask = shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL;
469 struct scsi_cmnd *cmd;
470
471 spin_lock_init(&shost->free_list_lock);
472 INIT_LIST_HEAD(&shost->free_list);
473
474 shost->cmd_pool = scsi_get_host_cmd_pool(shost);
475 if (!shost->cmd_pool)
476 return -ENOMEM;
477
478 /*
479 * Get one backup command for this host.
480 */
481 cmd = scsi_host_alloc_command(shost, gfp_mask);
482 if (!cmd) {
483 scsi_put_host_cmd_pool(shost);
484 shost->cmd_pool = NULL;
485 return -ENOMEM;
486 }
487 list_add(&cmd->list, &shost->free_list);
488 return 0;
489}
490
491/**
492 * scsi_destroy_command_freelist - Release the command freelist for a scsi host.
493 * @shost: host whose freelist is going to be destroyed
494 */
495void scsi_destroy_command_freelist(struct Scsi_Host *shost)
496{
497 /*
498 * If cmd_pool is NULL the free list was not initialized, so
499 * do not attempt to release resources.
500 */
501 if (!shost->cmd_pool)
502 return;
503
504 while (!list_empty(&shost->free_list)) {
505 struct scsi_cmnd *cmd;
506
507 cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
508 list_del_init(&cmd->list);
509 scsi_host_free_command(shost, cmd);
510 }
511 shost->cmd_pool = NULL;
512 scsi_put_host_cmd_pool(shost);
513}
514
515#ifdef CONFIG_SCSI_LOGGING
516void scsi_log_send(struct scsi_cmnd *cmd)
517{
518 unsigned int level;
519
520 /*
521 * If ML QUEUE log level is greater than or equal to:
522 *
523 * 1: nothing (match completion)
524 *
525 * 2: log opcode + command of all commands
526 *
527 * 3: same as 2 plus dump cmd address
528 *
529 * 4: same as 3 plus dump extra junk
530 */
531 if (unlikely(scsi_logging_level)) {
532 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
533 SCSI_LOG_MLQUEUE_BITS);
534 if (level > 1) {
535 scmd_printk(KERN_INFO, cmd, "Send: ");
536 if (level > 2)
537 printk("0x%p ", cmd);
538 printk("\n");
539 scsi_print_command(cmd);
540 if (level > 3) {
541 printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
542 " queuecommand 0x%p\n",
543 scsi_sglist(cmd), scsi_bufflen(cmd),
544 cmd->device->host->hostt->queuecommand);
545
546 }
547 }
548 }
549}
550
551void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
552{
553 unsigned int level;
554
555 /*
556 * If ML COMPLETE log level is greater than or equal to:
557 *
558 * 1: log disposition, result, opcode + command, and conditionally
559 * sense data for failures or non SUCCESS dispositions.
560 *
561 * 2: same as 1 but for all command completions.
562 *
563 * 3: same as 2 plus dump cmd address
564 *
565 * 4: same as 3 plus dump extra junk
566 */
567 if (unlikely(scsi_logging_level)) {
568 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
569 SCSI_LOG_MLCOMPLETE_BITS);
570 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
571 (level > 1)) {
572 scmd_printk(KERN_INFO, cmd, "Done: ");
573 if (level > 2)
574 printk("0x%p ", cmd);
575 /*
576 * Dump truncated values, so we usually fit within
577 * 80 chars.
578 */
579 switch (disposition) {
580 case SUCCESS:
581 printk("SUCCESS\n");
582 break;
583 case NEEDS_RETRY:
584 printk("RETRY\n");
585 break;
586 case ADD_TO_MLQUEUE:
587 printk("MLQUEUE\n");
588 break;
589 case FAILED:
590 printk("FAILED\n");
591 break;
592 case TIMEOUT_ERROR:
593 /*
594 * If called via scsi_times_out.
595 */
596 printk("TIMEOUT\n");
597 break;
598 default:
599 printk("UNKNOWN\n");
600 }
601 scsi_print_result(cmd);
602 scsi_print_command(cmd);
603 if (status_byte(cmd->result) & CHECK_CONDITION)
604 scsi_print_sense("", cmd);
605 if (level > 3)
606 scmd_printk(KERN_INFO, cmd,
607 "scsi host busy %d failed %d\n",
608 cmd->device->host->host_busy,
609 cmd->device->host->host_failed);
610 }
611 }
612}
613#endif
614
615/**
616 * scsi_cmd_get_serial - Assign a serial number to a command
617 * @host: the scsi host
618 * @cmd: command to assign serial number to
619 *
620 * Description: a serial number identifies a request for error recovery
621 * and debugging purposes. Protected by the Host_Lock of host.
622 */
623void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
624{
625 cmd->serial_number = host->cmd_serial_number++;
626 if (cmd->serial_number == 0)
627 cmd->serial_number = host->cmd_serial_number++;
628}
629EXPORT_SYMBOL(scsi_cmd_get_serial);
630
631/**
632 * scsi_dispatch_command - Dispatch a command to the low-level driver.
633 * @cmd: command block we are dispatching.
634 *
635 * Return: nonzero return request was rejected and device's queue needs to be
636 * plugged.
637 */
638int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
639{
640 struct Scsi_Host *host = cmd->device->host;
641 int rtn = 0;
642
643 atomic_inc(&cmd->device->iorequest_cnt);
644
645 /* check if the device is still usable */
646 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
647 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
648 * returns an immediate error upwards, and signals
649 * that the device is no longer present */
650 cmd->result = DID_NO_CONNECT << 16;
651 scsi_done(cmd);
652 /* return 0 (because the command has been processed) */
653 goto out;
654 }
655
656 /* Check to see if the scsi lld made this device blocked. */
657 if (unlikely(scsi_device_blocked(cmd->device))) {
658 /*
659 * in blocked state, the command is just put back on
660 * the device queue. The suspend state has already
661 * blocked the queue so future requests should not
662 * occur until the device transitions out of the
663 * suspend state.
664 */
665
666 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
667
668 SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
669
670 /*
671 * NOTE: rtn is still zero here because we don't need the
672 * queue to be plugged on return (it's already stopped)
673 */
674 goto out;
675 }
676
677 /*
678 * If SCSI-2 or lower, store the LUN value in cmnd.
679 */
680 if (cmd->device->scsi_level <= SCSI_2 &&
681 cmd->device->scsi_level != SCSI_UNKNOWN) {
682 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
683 (cmd->device->lun << 5 & 0xe0);
684 }
685
686 scsi_log_send(cmd);
687
688 /*
689 * Before we queue this command, check if the command
690 * length exceeds what the host adapter can handle.
691 */
692 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
693 SCSI_LOG_MLQUEUE(3,
694 printk("queuecommand : command too long. "
695 "cdb_size=%d host->max_cmd_len=%d\n",
696 cmd->cmd_len, cmd->device->host->max_cmd_len));
697 cmd->result = (DID_ABORT << 16);
698
699 scsi_done(cmd);
700 goto out;
701 }
702
703 if (unlikely(host->shost_state == SHOST_DEL)) {
704 cmd->result = (DID_NO_CONNECT << 16);
705 scsi_done(cmd);
706 } else {
707 trace_scsi_dispatch_cmd_start(cmd);
708 cmd->scsi_done = scsi_done;
709 rtn = host->hostt->queuecommand(host, cmd);
710 }
711
712 if (rtn) {
713 trace_scsi_dispatch_cmd_error(cmd, rtn);
714 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
715 rtn != SCSI_MLQUEUE_TARGET_BUSY)
716 rtn = SCSI_MLQUEUE_HOST_BUSY;
717
718 scsi_queue_insert(cmd, rtn);
719
720 SCSI_LOG_MLQUEUE(3,
721 printk("queuecommand : request rejected\n"));
722 }
723
724 out:
725 SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
726 return rtn;
727}
728
729/**
730 * scsi_done - Invoke completion on finished SCSI command.
731 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
732 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
733 *
734 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
735 * which regains ownership of the SCSI command (de facto) from a LLDD, and
736 * calls blk_complete_request() for further processing.
737 *
738 * This function is interrupt context safe.
739 */
740static void scsi_done(struct scsi_cmnd *cmd)
741{
742 trace_scsi_dispatch_cmd_done(cmd);
743 blk_complete_request(cmd->request);
744}
745
746/**
747 * scsi_finish_command - cleanup and pass command back to upper layer
748 * @cmd: the command
749 *
750 * Description: Pass command off to upper layer for finishing of I/O
751 * request, waking processes that are waiting on results,
752 * etc.
753 */
754void scsi_finish_command(struct scsi_cmnd *cmd)
755{
756 struct scsi_device *sdev = cmd->device;
757 struct scsi_target *starget = scsi_target(sdev);
758 struct Scsi_Host *shost = sdev->host;
759 struct scsi_driver *drv;
760 unsigned int good_bytes;
761
762 scsi_device_unbusy(sdev);
763
764 /*
765 * Clear the flags which say that the device/host is no longer
766 * capable of accepting new commands. These are set in scsi_queue.c
767 * for both the queue full condition on a device, and for a
768 * host full condition on the host.
769 *
770 * XXX(hch): What about locking?
771 */
772 shost->host_blocked = 0;
773 starget->target_blocked = 0;
774 sdev->device_blocked = 0;
775
776 /*
777 * If we have valid sense information, then some kind of recovery
778 * must have taken place. Make a note of this.
779 */
780 if (SCSI_SENSE_VALID(cmd))
781 cmd->result |= (DRIVER_SENSE << 24);
782
783 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
784 "Notifying upper driver of completion "
785 "(result %x)\n", cmd->result));
786
787 good_bytes = scsi_bufflen(cmd);
788 if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
789 int old_good_bytes = good_bytes;
790 drv = scsi_cmd_to_driver(cmd);
791 if (drv->done)
792 good_bytes = drv->done(cmd);
793 /*
794 * USB may not give sense identifying bad sector and
795 * simply return a residue instead, so subtract off the
796 * residue if drv->done() error processing indicates no
797 * change to the completion length.
798 */
799 if (good_bytes == old_good_bytes)
800 good_bytes -= scsi_get_resid(cmd);
801 }
802 scsi_io_completion(cmd, good_bytes);
803}
804EXPORT_SYMBOL(scsi_finish_command);
805
806/**
807 * scsi_adjust_queue_depth - Let low level drivers change a device's queue depth
808 * @sdev: SCSI Device in question
809 * @tagged: Do we use tagged queueing (non-0) or do we treat
810 * this device as an untagged device (0)
811 * @tags: Number of tags allowed if tagged queueing enabled,
812 * or number of commands the low level driver can
813 * queue up in non-tagged mode (as per cmd_per_lun).
814 *
815 * Returns: Nothing
816 *
817 * Lock Status: None held on entry
818 *
819 * Notes: Low level drivers may call this at any time and we will do
820 * the right thing depending on whether or not the device is
821 * currently active and whether or not it even has the
822 * command blocks built yet.
823 */
824void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
825{
826 unsigned long flags;
827
828 /*
829 * refuse to set tagged depth to an unworkable size
830 */
831 if (tags <= 0)
832 return;
833
834 spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
835
836 /*
837 * Check to see if the queue is managed by the block layer.
838 * If it is, and we fail to adjust the depth, exit.
839 *
840 * Do not resize the tag map if it is a host wide share bqt,
841 * because the size should be the hosts's can_queue. If there
842 * is more IO than the LLD's can_queue (so there are not enuogh
843 * tags) request_fn's host queue ready check will handle it.
844 */
845 if (!sdev->host->bqt) {
846 if (blk_queue_tagged(sdev->request_queue) &&
847 blk_queue_resize_tags(sdev->request_queue, tags) != 0)
848 goto out;
849 }
850
851 sdev->queue_depth = tags;
852 switch (tagged) {
853 case MSG_ORDERED_TAG:
854 sdev->ordered_tags = 1;
855 sdev->simple_tags = 1;
856 break;
857 case MSG_SIMPLE_TAG:
858 sdev->ordered_tags = 0;
859 sdev->simple_tags = 1;
860 break;
861 default:
862 sdev_printk(KERN_WARNING, sdev,
863 "scsi_adjust_queue_depth, bad queue type, "
864 "disabled\n");
865 case 0:
866 sdev->ordered_tags = sdev->simple_tags = 0;
867 sdev->queue_depth = tags;
868 break;
869 }
870 out:
871 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
872}
873EXPORT_SYMBOL(scsi_adjust_queue_depth);
874
875/**
876 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
877 * @sdev: SCSI Device in question
878 * @depth: Current number of outstanding SCSI commands on this device,
879 * not counting the one returned as QUEUE_FULL.
880 *
881 * Description: This function will track successive QUEUE_FULL events on a
882 * specific SCSI device to determine if and when there is a
883 * need to adjust the queue depth on the device.
884 *
885 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
886 * -1 - Drop back to untagged operation using host->cmd_per_lun
887 * as the untagged command depth
888 *
889 * Lock Status: None held on entry
890 *
891 * Notes: Low level drivers may call this at any time and we will do
892 * "The Right Thing." We are interrupt context safe.
893 */
894int scsi_track_queue_full(struct scsi_device *sdev, int depth)
895{
896
897 /*
898 * Don't let QUEUE_FULLs on the same
899 * jiffies count, they could all be from
900 * same event.
901 */
902 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
903 return 0;
904
905 sdev->last_queue_full_time = jiffies;
906 if (sdev->last_queue_full_depth != depth) {
907 sdev->last_queue_full_count = 1;
908 sdev->last_queue_full_depth = depth;
909 } else {
910 sdev->last_queue_full_count++;
911 }
912
913 if (sdev->last_queue_full_count <= 10)
914 return 0;
915 if (sdev->last_queue_full_depth < 8) {
916 /* Drop back to untagged */
917 scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
918 return -1;
919 }
920
921 if (sdev->ordered_tags)
922 scsi_adjust_queue_depth(sdev, MSG_ORDERED_TAG, depth);
923 else
924 scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
925 return depth;
926}
927EXPORT_SYMBOL(scsi_track_queue_full);
928
929/**
930 * scsi_vpd_inquiry - Request a device provide us with a VPD page
931 * @sdev: The device to ask
932 * @buffer: Where to put the result
933 * @page: Which Vital Product Data to return
934 * @len: The length of the buffer
935 *
936 * This is an internal helper function. You probably want to use
937 * scsi_get_vpd_page instead.
938 *
939 * Returns size of the vpd page on success or a negative error number.
940 */
941static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
942 u8 page, unsigned len)
943{
944 int result;
945 unsigned char cmd[16];
946
947 if (len < 4)
948 return -EINVAL;
949
950 cmd[0] = INQUIRY;
951 cmd[1] = 1; /* EVPD */
952 cmd[2] = page;
953 cmd[3] = len >> 8;
954 cmd[4] = len & 0xff;
955 cmd[5] = 0; /* Control byte */
956
957 /*
958 * I'm not convinced we need to try quite this hard to get VPD, but
959 * all the existing users tried this hard.
960 */
961 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
962 len, NULL, 30 * HZ, 3, NULL);
963 if (result)
964 return -EIO;
965
966 /* Sanity check that we got the page back that we asked for */
967 if (buffer[1] != page)
968 return -EIO;
969
970 return get_unaligned_be16(&buffer[2]) + 4;
971}
972
973/**
974 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
975 * @sdev: The device to ask
976 * @page: Which Vital Product Data to return
977 * @buf: where to store the VPD
978 * @buf_len: number of bytes in the VPD buffer area
979 *
980 * SCSI devices may optionally supply Vital Product Data. Each 'page'
981 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
982 * If the device supports this VPD page, this routine returns a pointer
983 * to a buffer containing the data from that page. The caller is
984 * responsible for calling kfree() on this pointer when it is no longer
985 * needed. If we cannot retrieve the VPD page this routine returns %NULL.
986 */
987int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
988 int buf_len)
989{
990 int i, result;
991
992 if (sdev->skip_vpd_pages)
993 goto fail;
994
995 /* Ask for all the pages supported by this device */
996 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len);
997 if (result < 4)
998 goto fail;
999
1000 /* If the user actually wanted this page, we can skip the rest */
1001 if (page == 0)
1002 return 0;
1003
1004 for (i = 4; i < min(result, buf_len); i++)
1005 if (buf[i] == page)
1006 goto found;
1007
1008 if (i < result && i >= buf_len)
1009 /* ran off the end of the buffer, give us benefit of doubt */
1010 goto found;
1011 /* The device claims it doesn't support the requested page */
1012 goto fail;
1013
1014 found:
1015 result = scsi_vpd_inquiry(sdev, buf, page, buf_len);
1016 if (result < 0)
1017 goto fail;
1018
1019 return 0;
1020
1021 fail:
1022 return -EINVAL;
1023}
1024EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
1025
1026/**
1027 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure
1028 * @sdev: The device to ask
1029 *
1030 * Attach the 'Device Identification' VPD page (0x83) and the
1031 * 'Unit Serial Number' VPD page (0x80) to a SCSI device
1032 * structure. This information can be used to identify the device
1033 * uniquely.
1034 */
1035void scsi_attach_vpd(struct scsi_device *sdev)
1036{
1037 int result, i;
1038 int vpd_len = SCSI_VPD_PG_LEN;
1039 int pg80_supported = 0;
1040 int pg83_supported = 0;
1041 unsigned char *vpd_buf;
1042
1043 if (sdev->skip_vpd_pages)
1044 return;
1045retry_pg0:
1046 vpd_buf = kmalloc(vpd_len, GFP_KERNEL);
1047 if (!vpd_buf)
1048 return;
1049
1050 /* Ask for all the pages supported by this device */
1051 result = scsi_vpd_inquiry(sdev, vpd_buf, 0, vpd_len);
1052 if (result < 0) {
1053 kfree(vpd_buf);
1054 return;
1055 }
1056 if (result > vpd_len) {
1057 vpd_len = result;
1058 kfree(vpd_buf);
1059 goto retry_pg0;
1060 }
1061
1062 for (i = 4; i < result; i++) {
1063 if (vpd_buf[i] == 0x80)
1064 pg80_supported = 1;
1065 if (vpd_buf[i] == 0x83)
1066 pg83_supported = 1;
1067 }
1068 kfree(vpd_buf);
1069 vpd_len = SCSI_VPD_PG_LEN;
1070
1071 if (pg80_supported) {
1072retry_pg80:
1073 vpd_buf = kmalloc(vpd_len, GFP_KERNEL);
1074 if (!vpd_buf)
1075 return;
1076
1077 result = scsi_vpd_inquiry(sdev, vpd_buf, 0x80, vpd_len);
1078 if (result < 0) {
1079 kfree(vpd_buf);
1080 return;
1081 }
1082 if (result > vpd_len) {
1083 vpd_len = result;
1084 kfree(vpd_buf);
1085 goto retry_pg80;
1086 }
1087 sdev->vpd_pg80_len = result;
1088 sdev->vpd_pg80 = vpd_buf;
1089 vpd_len = SCSI_VPD_PG_LEN;
1090 }
1091
1092 if (pg83_supported) {
1093retry_pg83:
1094 vpd_buf = kmalloc(vpd_len, GFP_KERNEL);
1095 if (!vpd_buf)
1096 return;
1097
1098 result = scsi_vpd_inquiry(sdev, vpd_buf, 0x83, vpd_len);
1099 if (result < 0) {
1100 kfree(vpd_buf);
1101 return;
1102 }
1103 if (result > vpd_len) {
1104 vpd_len = result;
1105 kfree(vpd_buf);
1106 goto retry_pg83;
1107 }
1108 sdev->vpd_pg83_len = result;
1109 sdev->vpd_pg83 = vpd_buf;
1110 }
1111}
1112
1113/**
1114 * scsi_report_opcode - Find out if a given command opcode is supported
1115 * @sdev: scsi device to query
1116 * @buffer: scratch buffer (must be at least 20 bytes long)
1117 * @len: length of buffer
1118 * @opcode: opcode for command to look up
1119 *
1120 * Uses the REPORT SUPPORTED OPERATION CODES to look up the given
1121 * opcode. Returns -EINVAL if RSOC fails, 0 if the command opcode is
1122 * unsupported and 1 if the device claims to support the command.
1123 */
1124int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,
1125 unsigned int len, unsigned char opcode)
1126{
1127 unsigned char cmd[16];
1128 struct scsi_sense_hdr sshdr;
1129 int result;
1130
1131 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3)
1132 return -EINVAL;
1133
1134 memset(cmd, 0, 16);
1135 cmd[0] = MAINTENANCE_IN;
1136 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES;
1137 cmd[2] = 1; /* One command format */
1138 cmd[3] = opcode;
1139 put_unaligned_be32(len, &cmd[6]);
1140 memset(buffer, 0, len);
1141
1142 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
1143 &sshdr, 30 * HZ, 3, NULL);
1144
1145 if (result && scsi_sense_valid(&sshdr) &&
1146 sshdr.sense_key == ILLEGAL_REQUEST &&
1147 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00)
1148 return -EINVAL;
1149
1150 if ((buffer[1] & 3) == 3) /* Command supported */
1151 return 1;
1152
1153 return 0;
1154}
1155EXPORT_SYMBOL(scsi_report_opcode);
1156
1157/**
1158 * scsi_device_get - get an additional reference to a scsi_device
1159 * @sdev: device to get a reference to
1160 *
1161 * Description: Gets a reference to the scsi_device and increments the use count
1162 * of the underlying LLDD module. You must hold host_lock of the
1163 * parent Scsi_Host or already have a reference when calling this.
1164 */
1165int scsi_device_get(struct scsi_device *sdev)
1166{
1167 if (sdev->sdev_state == SDEV_DEL)
1168 return -ENXIO;
1169 if (!get_device(&sdev->sdev_gendev))
1170 return -ENXIO;
1171 /* We can fail this if we're doing SCSI operations
1172 * from module exit (like cache flush) */
1173 try_module_get(sdev->host->hostt->module);
1174
1175 return 0;
1176}
1177EXPORT_SYMBOL(scsi_device_get);
1178
1179/**
1180 * scsi_device_put - release a reference to a scsi_device
1181 * @sdev: device to release a reference on.
1182 *
1183 * Description: Release a reference to the scsi_device and decrements the use
1184 * count of the underlying LLDD module. The device is freed once the last
1185 * user vanishes.
1186 */
1187void scsi_device_put(struct scsi_device *sdev)
1188{
1189#ifdef CONFIG_MODULE_UNLOAD
1190 struct module *module = sdev->host->hostt->module;
1191
1192 /* The module refcount will be zero if scsi_device_get()
1193 * was called from a module removal routine */
1194 if (module && module_refcount(module) != 0)
1195 module_put(module);
1196#endif
1197 put_device(&sdev->sdev_gendev);
1198}
1199EXPORT_SYMBOL(scsi_device_put);
1200
1201/* helper for shost_for_each_device, see that for documentation */
1202struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
1203 struct scsi_device *prev)
1204{
1205 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
1206 struct scsi_device *next = NULL;
1207 unsigned long flags;
1208
1209 spin_lock_irqsave(shost->host_lock, flags);
1210 while (list->next != &shost->__devices) {
1211 next = list_entry(list->next, struct scsi_device, siblings);
1212 /* skip devices that we can't get a reference to */
1213 if (!scsi_device_get(next))
1214 break;
1215 next = NULL;
1216 list = list->next;
1217 }
1218 spin_unlock_irqrestore(shost->host_lock, flags);
1219
1220 if (prev)
1221 scsi_device_put(prev);
1222 return next;
1223}
1224EXPORT_SYMBOL(__scsi_iterate_devices);
1225
1226/**
1227 * starget_for_each_device - helper to walk all devices of a target
1228 * @starget: target whose devices we want to iterate over.
1229 * @data: Opaque passed to each function call.
1230 * @fn: Function to call on each device
1231 *
1232 * This traverses over each device of @starget. The devices have
1233 * a reference that must be released by scsi_host_put when breaking
1234 * out of the loop.
1235 */
1236void starget_for_each_device(struct scsi_target *starget, void *data,
1237 void (*fn)(struct scsi_device *, void *))
1238{
1239 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1240 struct scsi_device *sdev;
1241
1242 shost_for_each_device(sdev, shost) {
1243 if ((sdev->channel == starget->channel) &&
1244 (sdev->id == starget->id))
1245 fn(sdev, data);
1246 }
1247}
1248EXPORT_SYMBOL(starget_for_each_device);
1249
1250/**
1251 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
1252 * @starget: target whose devices we want to iterate over.
1253 * @data: parameter for callback @fn()
1254 * @fn: callback function that is invoked for each device
1255 *
1256 * This traverses over each device of @starget. It does _not_
1257 * take a reference on the scsi_device, so the whole loop must be
1258 * protected by shost->host_lock.
1259 *
1260 * Note: The only reason why drivers would want to use this is because
1261 * they need to access the device list in irq context. Otherwise you
1262 * really want to use starget_for_each_device instead.
1263 **/
1264void __starget_for_each_device(struct scsi_target *starget, void *data,
1265 void (*fn)(struct scsi_device *, void *))
1266{
1267 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1268 struct scsi_device *sdev;
1269
1270 __shost_for_each_device(sdev, shost) {
1271 if ((sdev->channel == starget->channel) &&
1272 (sdev->id == starget->id))
1273 fn(sdev, data);
1274 }
1275}
1276EXPORT_SYMBOL(__starget_for_each_device);
1277
1278/**
1279 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
1280 * @starget: SCSI target pointer
1281 * @lun: SCSI Logical Unit Number
1282 *
1283 * Description: Looks up the scsi_device with the specified @lun for a given
1284 * @starget. The returned scsi_device does not have an additional
1285 * reference. You must hold the host's host_lock over this call and
1286 * any access to the returned scsi_device. A scsi_device in state
1287 * SDEV_DEL is skipped.
1288 *
1289 * Note: The only reason why drivers should use this is because
1290 * they need to access the device list in irq context. Otherwise you
1291 * really want to use scsi_device_lookup_by_target instead.
1292 **/
1293struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
1294 uint lun)
1295{
1296 struct scsi_device *sdev;
1297
1298 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
1299 if (sdev->sdev_state == SDEV_DEL)
1300 continue;
1301 if (sdev->lun ==lun)
1302 return sdev;
1303 }
1304
1305 return NULL;
1306}
1307EXPORT_SYMBOL(__scsi_device_lookup_by_target);
1308
1309/**
1310 * scsi_device_lookup_by_target - find a device given the target
1311 * @starget: SCSI target pointer
1312 * @lun: SCSI Logical Unit Number
1313 *
1314 * Description: Looks up the scsi_device with the specified @lun for a given
1315 * @starget. The returned scsi_device has an additional reference that
1316 * needs to be released with scsi_device_put once you're done with it.
1317 **/
1318struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
1319 uint lun)
1320{
1321 struct scsi_device *sdev;
1322 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1323 unsigned long flags;
1324
1325 spin_lock_irqsave(shost->host_lock, flags);
1326 sdev = __scsi_device_lookup_by_target(starget, lun);
1327 if (sdev && scsi_device_get(sdev))
1328 sdev = NULL;
1329 spin_unlock_irqrestore(shost->host_lock, flags);
1330
1331 return sdev;
1332}
1333EXPORT_SYMBOL(scsi_device_lookup_by_target);
1334
1335/**
1336 * __scsi_device_lookup - find a device given the host (UNLOCKED)
1337 * @shost: SCSI host pointer
1338 * @channel: SCSI channel (zero if only one channel)
1339 * @id: SCSI target number (physical unit number)
1340 * @lun: SCSI Logical Unit Number
1341 *
1342 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1343 * for a given host. The returned scsi_device does not have an additional
1344 * reference. You must hold the host's host_lock over this call and any access
1345 * to the returned scsi_device.
1346 *
1347 * Note: The only reason why drivers would want to use this is because
1348 * they need to access the device list in irq context. Otherwise you
1349 * really want to use scsi_device_lookup instead.
1350 **/
1351struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
1352 uint channel, uint id, uint lun)
1353{
1354 struct scsi_device *sdev;
1355
1356 list_for_each_entry(sdev, &shost->__devices, siblings) {
1357 if (sdev->channel == channel && sdev->id == id &&
1358 sdev->lun ==lun)
1359 return sdev;
1360 }
1361
1362 return NULL;
1363}
1364EXPORT_SYMBOL(__scsi_device_lookup);
1365
1366/**
1367 * scsi_device_lookup - find a device given the host
1368 * @shost: SCSI host pointer
1369 * @channel: SCSI channel (zero if only one channel)
1370 * @id: SCSI target number (physical unit number)
1371 * @lun: SCSI Logical Unit Number
1372 *
1373 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1374 * for a given host. The returned scsi_device has an additional reference that
1375 * needs to be released with scsi_device_put once you're done with it.
1376 **/
1377struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1378 uint channel, uint id, uint lun)
1379{
1380 struct scsi_device *sdev;
1381 unsigned long flags;
1382
1383 spin_lock_irqsave(shost->host_lock, flags);
1384 sdev = __scsi_device_lookup(shost, channel, id, lun);
1385 if (sdev && scsi_device_get(sdev))
1386 sdev = NULL;
1387 spin_unlock_irqrestore(shost->host_lock, flags);
1388
1389 return sdev;
1390}
1391EXPORT_SYMBOL(scsi_device_lookup);
1392
1393MODULE_DESCRIPTION("SCSI core");
1394MODULE_LICENSE("GPL");
1395
1396module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1397MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1398
1399static int __init init_scsi(void)
1400{
1401 int error;
1402
1403 error = scsi_init_queue();
1404 if (error)
1405 return error;
1406 error = scsi_init_procfs();
1407 if (error)
1408 goto cleanup_queue;
1409 error = scsi_init_devinfo();
1410 if (error)
1411 goto cleanup_procfs;
1412 error = scsi_init_hosts();
1413 if (error)
1414 goto cleanup_devlist;
1415 error = scsi_init_sysctl();
1416 if (error)
1417 goto cleanup_hosts;
1418 error = scsi_sysfs_register();
1419 if (error)
1420 goto cleanup_sysctl;
1421
1422 scsi_netlink_init();
1423
1424 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1425 return 0;
1426
1427cleanup_sysctl:
1428 scsi_exit_sysctl();
1429cleanup_hosts:
1430 scsi_exit_hosts();
1431cleanup_devlist:
1432 scsi_exit_devinfo();
1433cleanup_procfs:
1434 scsi_exit_procfs();
1435cleanup_queue:
1436 scsi_exit_queue();
1437 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1438 -error);
1439 return error;
1440}
1441
1442static void __exit exit_scsi(void)
1443{
1444 scsi_netlink_exit();
1445 scsi_sysfs_unregister();
1446 scsi_exit_sysctl();
1447 scsi_exit_hosts();
1448 scsi_exit_devinfo();
1449 scsi_exit_procfs();
1450 scsi_exit_queue();
1451 async_unregister_domain(&scsi_sd_probe_domain);
1452}
1453
1454subsys_initcall(init_scsi);
1455module_exit(exit_scsi);
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
5 *
6 * generic mid-level SCSI driver
7 * Initial versions: Drew Eckhardt
8 * Subsequent revisions: Eric Youngdale
9 *
10 * <drew@colorado.edu>
11 *
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>
16 *
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.
20 *
21 * Native multichannel, wide scsi, /proc/scsi and hot plugging
22 * support added by Michael Neuffer <mike@i-connect.net>
23 *
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)
28 *
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>
32 *
33 * Converted cli() code to spinlocks, Ingo Molnar
34 *
35 * Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
36 *
37 * out_of_space hacks, D. Gilbert (dpg) 990608
38 */
39
40#include <linux/module.h>
41#include <linux/moduleparam.h>
42#include <linux/kernel.h>
43#include <linux/timer.h>
44#include <linux/string.h>
45#include <linux/slab.h>
46#include <linux/blkdev.h>
47#include <linux/delay.h>
48#include <linux/init.h>
49#include <linux/completion.h>
50#include <linux/unistd.h>
51#include <linux/spinlock.h>
52#include <linux/kmod.h>
53#include <linux/interrupt.h>
54#include <linux/notifier.h>
55#include <linux/cpu.h>
56#include <linux/mutex.h>
57
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>
66
67#include "scsi_priv.h"
68#include "scsi_logging.h"
69
70#define CREATE_TRACE_POINTS
71#include <trace/events/scsi.h>
72
73static void scsi_done(struct scsi_cmnd *cmd);
74
75/*
76 * Definitions and constants.
77 */
78
79#define MIN_RESET_DELAY (2*HZ)
80
81/* Do not call reset on error if we just did a reset within 15 sec. */
82#define MIN_RESET_PERIOD (15*HZ)
83
84/*
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.
87 */
88unsigned int scsi_logging_level;
89#if defined(CONFIG_SCSI_LOGGING)
90EXPORT_SYMBOL(scsi_logging_level);
91#endif
92
93/* sd, scsi core and power management need to coordinate flushing async actions */
94LIST_HEAD(scsi_sd_probe_domain);
95EXPORT_SYMBOL(scsi_sd_probe_domain);
96
97/* NB: These are exposed through /proc/scsi/scsi and form part of the ABI.
98 * You may not alter any existing entry (although adding new ones is
99 * encouraged once assigned by ANSI/INCITS T10
100 */
101static const char *const scsi_device_types[] = {
102 "Direct-Access ",
103 "Sequential-Access",
104 "Printer ",
105 "Processor ",
106 "WORM ",
107 "CD-ROM ",
108 "Scanner ",
109 "Optical Device ",
110 "Medium Changer ",
111 "Communications ",
112 "ASC IT8 ",
113 "ASC IT8 ",
114 "RAID ",
115 "Enclosure ",
116 "Direct-Access-RBC",
117 "Optical card ",
118 "Bridge controller",
119 "Object storage ",
120 "Automation/Drive ",
121};
122
123/**
124 * scsi_device_type - Return 17 char string indicating device type.
125 * @type: type number to look up
126 */
127
128const char * scsi_device_type(unsigned type)
129{
130 if (type == 0x1e)
131 return "Well-known LUN ";
132 if (type == 0x1f)
133 return "No Device ";
134 if (type >= ARRAY_SIZE(scsi_device_types))
135 return "Unknown ";
136 return scsi_device_types[type];
137}
138
139EXPORT_SYMBOL(scsi_device_type);
140
141struct scsi_host_cmd_pool {
142 struct kmem_cache *cmd_slab;
143 struct kmem_cache *sense_slab;
144 unsigned int users;
145 char *cmd_name;
146 char *sense_name;
147 unsigned int slab_flags;
148 gfp_t gfp_mask;
149};
150
151static struct scsi_host_cmd_pool scsi_cmd_pool = {
152 .cmd_name = "scsi_cmd_cache",
153 .sense_name = "scsi_sense_cache",
154 .slab_flags = SLAB_HWCACHE_ALIGN,
155};
156
157static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
158 .cmd_name = "scsi_cmd_cache(DMA)",
159 .sense_name = "scsi_sense_cache(DMA)",
160 .slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA,
161 .gfp_mask = __GFP_DMA,
162};
163
164static DEFINE_MUTEX(host_cmd_pool_mutex);
165
166/**
167 * scsi_pool_alloc_command - internal function to get a fully allocated command
168 * @pool: slab pool to allocate the command from
169 * @gfp_mask: mask for the allocation
170 *
171 * Returns a fully allocated command (with the allied sense buffer) or
172 * NULL on failure
173 */
174static struct scsi_cmnd *
175scsi_pool_alloc_command(struct scsi_host_cmd_pool *pool, gfp_t gfp_mask)
176{
177 struct scsi_cmnd *cmd;
178
179 cmd = kmem_cache_zalloc(pool->cmd_slab, gfp_mask | pool->gfp_mask);
180 if (!cmd)
181 return NULL;
182
183 cmd->sense_buffer = kmem_cache_alloc(pool->sense_slab,
184 gfp_mask | pool->gfp_mask);
185 if (!cmd->sense_buffer) {
186 kmem_cache_free(pool->cmd_slab, cmd);
187 return NULL;
188 }
189
190 return cmd;
191}
192
193/**
194 * scsi_pool_free_command - internal function to release a command
195 * @pool: slab pool to allocate the command from
196 * @cmd: command to release
197 *
198 * the command must previously have been allocated by
199 * scsi_pool_alloc_command.
200 */
201static void
202scsi_pool_free_command(struct scsi_host_cmd_pool *pool,
203 struct scsi_cmnd *cmd)
204{
205 if (cmd->prot_sdb)
206 kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb);
207
208 kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
209 kmem_cache_free(pool->cmd_slab, cmd);
210}
211
212/**
213 * scsi_host_alloc_command - internal function to allocate command
214 * @shost: SCSI host whose pool to allocate from
215 * @gfp_mask: mask for the allocation
216 *
217 * Returns a fully allocated command with sense buffer and protection
218 * data buffer (where applicable) or NULL on failure
219 */
220static struct scsi_cmnd *
221scsi_host_alloc_command(struct Scsi_Host *shost, gfp_t gfp_mask)
222{
223 struct scsi_cmnd *cmd;
224
225 cmd = scsi_pool_alloc_command(shost->cmd_pool, gfp_mask);
226 if (!cmd)
227 return NULL;
228
229 if (scsi_host_get_prot(shost) >= SHOST_DIX_TYPE0_PROTECTION) {
230 cmd->prot_sdb = kmem_cache_zalloc(scsi_sdb_cache, gfp_mask);
231
232 if (!cmd->prot_sdb) {
233 scsi_pool_free_command(shost->cmd_pool, cmd);
234 return NULL;
235 }
236 }
237
238 return cmd;
239}
240
241/**
242 * __scsi_get_command - Allocate a struct scsi_cmnd
243 * @shost: host to transmit command
244 * @gfp_mask: allocation mask
245 *
246 * Description: allocate a struct scsi_cmd from host's slab, recycling from the
247 * host's free_list if necessary.
248 */
249struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
250{
251 struct scsi_cmnd *cmd = scsi_host_alloc_command(shost, gfp_mask);
252
253 if (unlikely(!cmd)) {
254 unsigned long flags;
255
256 spin_lock_irqsave(&shost->free_list_lock, flags);
257 if (likely(!list_empty(&shost->free_list))) {
258 cmd = list_entry(shost->free_list.next,
259 struct scsi_cmnd, list);
260 list_del_init(&cmd->list);
261 }
262 spin_unlock_irqrestore(&shost->free_list_lock, flags);
263
264 if (cmd) {
265 void *buf, *prot;
266
267 buf = cmd->sense_buffer;
268 prot = cmd->prot_sdb;
269
270 memset(cmd, 0, sizeof(*cmd));
271
272 cmd->sense_buffer = buf;
273 cmd->prot_sdb = prot;
274 }
275 }
276
277 return cmd;
278}
279EXPORT_SYMBOL_GPL(__scsi_get_command);
280
281/**
282 * scsi_get_command - Allocate and setup a scsi command block
283 * @dev: parent scsi device
284 * @gfp_mask: allocator flags
285 *
286 * Returns: The allocated scsi command structure.
287 */
288struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
289{
290 struct scsi_cmnd *cmd;
291
292 /* Bail if we can't get a reference to the device */
293 if (!get_device(&dev->sdev_gendev))
294 return NULL;
295
296 cmd = __scsi_get_command(dev->host, gfp_mask);
297
298 if (likely(cmd != NULL)) {
299 unsigned long flags;
300
301 cmd->device = dev;
302 INIT_LIST_HEAD(&cmd->list);
303 spin_lock_irqsave(&dev->list_lock, flags);
304 list_add_tail(&cmd->list, &dev->cmd_list);
305 spin_unlock_irqrestore(&dev->list_lock, flags);
306 cmd->jiffies_at_alloc = jiffies;
307 } else
308 put_device(&dev->sdev_gendev);
309
310 return cmd;
311}
312EXPORT_SYMBOL(scsi_get_command);
313
314/**
315 * __scsi_put_command - Free a struct scsi_cmnd
316 * @shost: dev->host
317 * @cmd: Command to free
318 * @dev: parent scsi device
319 */
320void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd,
321 struct device *dev)
322{
323 unsigned long flags;
324
325 /* changing locks here, don't need to restore the irq state */
326 spin_lock_irqsave(&shost->free_list_lock, flags);
327 if (unlikely(list_empty(&shost->free_list))) {
328 list_add(&cmd->list, &shost->free_list);
329 cmd = NULL;
330 }
331 spin_unlock_irqrestore(&shost->free_list_lock, flags);
332
333 if (likely(cmd != NULL))
334 scsi_pool_free_command(shost->cmd_pool, cmd);
335
336 put_device(dev);
337}
338EXPORT_SYMBOL(__scsi_put_command);
339
340/**
341 * scsi_put_command - Free a scsi command block
342 * @cmd: command block to free
343 *
344 * Returns: Nothing.
345 *
346 * Notes: The command must not belong to any lists.
347 */
348void scsi_put_command(struct scsi_cmnd *cmd)
349{
350 struct scsi_device *sdev = cmd->device;
351 unsigned long flags;
352
353 /* serious error if the command hasn't come from a device list */
354 spin_lock_irqsave(&cmd->device->list_lock, flags);
355 BUG_ON(list_empty(&cmd->list));
356 list_del_init(&cmd->list);
357 spin_unlock_irqrestore(&cmd->device->list_lock, flags);
358
359 __scsi_put_command(cmd->device->host, cmd, &sdev->sdev_gendev);
360}
361EXPORT_SYMBOL(scsi_put_command);
362
363static struct scsi_host_cmd_pool *scsi_get_host_cmd_pool(gfp_t gfp_mask)
364{
365 struct scsi_host_cmd_pool *retval = NULL, *pool;
366 /*
367 * Select a command slab for this host and create it if not
368 * yet existent.
369 */
370 mutex_lock(&host_cmd_pool_mutex);
371 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
372 &scsi_cmd_pool;
373 if (!pool->users) {
374 pool->cmd_slab = kmem_cache_create(pool->cmd_name,
375 sizeof(struct scsi_cmnd), 0,
376 pool->slab_flags, NULL);
377 if (!pool->cmd_slab)
378 goto fail;
379
380 pool->sense_slab = kmem_cache_create(pool->sense_name,
381 SCSI_SENSE_BUFFERSIZE, 0,
382 pool->slab_flags, NULL);
383 if (!pool->sense_slab) {
384 kmem_cache_destroy(pool->cmd_slab);
385 goto fail;
386 }
387 }
388
389 pool->users++;
390 retval = pool;
391 fail:
392 mutex_unlock(&host_cmd_pool_mutex);
393 return retval;
394}
395
396static void scsi_put_host_cmd_pool(gfp_t gfp_mask)
397{
398 struct scsi_host_cmd_pool *pool;
399
400 mutex_lock(&host_cmd_pool_mutex);
401 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
402 &scsi_cmd_pool;
403 /*
404 * This may happen if a driver has a mismatched get and put
405 * of the command pool; the driver should be implicated in
406 * the stack trace
407 */
408 BUG_ON(pool->users == 0);
409
410 if (!--pool->users) {
411 kmem_cache_destroy(pool->cmd_slab);
412 kmem_cache_destroy(pool->sense_slab);
413 }
414 mutex_unlock(&host_cmd_pool_mutex);
415}
416
417/**
418 * scsi_allocate_command - get a fully allocated SCSI command
419 * @gfp_mask: allocation mask
420 *
421 * This function is for use outside of the normal host based pools.
422 * It allocates the relevant command and takes an additional reference
423 * on the pool it used. This function *must* be paired with
424 * scsi_free_command which also has the identical mask, otherwise the
425 * free pool counts will eventually go wrong and you'll trigger a bug.
426 *
427 * This function should *only* be used by drivers that need a static
428 * command allocation at start of day for internal functions.
429 */
430struct scsi_cmnd *scsi_allocate_command(gfp_t gfp_mask)
431{
432 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
433
434 if (!pool)
435 return NULL;
436
437 return scsi_pool_alloc_command(pool, gfp_mask);
438}
439EXPORT_SYMBOL(scsi_allocate_command);
440
441/**
442 * scsi_free_command - free a command allocated by scsi_allocate_command
443 * @gfp_mask: mask used in the original allocation
444 * @cmd: command to free
445 *
446 * Note: using the original allocation mask is vital because that's
447 * what determines which command pool we use to free the command. Any
448 * mismatch will cause the system to BUG eventually.
449 */
450void scsi_free_command(gfp_t gfp_mask, struct scsi_cmnd *cmd)
451{
452 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
453
454 /*
455 * this could trigger if the mask to scsi_allocate_command
456 * doesn't match this mask. Otherwise we're guaranteed that this
457 * succeeds because scsi_allocate_command must have taken a reference
458 * on the pool
459 */
460 BUG_ON(!pool);
461
462 scsi_pool_free_command(pool, cmd);
463 /*
464 * scsi_put_host_cmd_pool is called twice; once to release the
465 * reference we took above, and once to release the reference
466 * originally taken by scsi_allocate_command
467 */
468 scsi_put_host_cmd_pool(gfp_mask);
469 scsi_put_host_cmd_pool(gfp_mask);
470}
471EXPORT_SYMBOL(scsi_free_command);
472
473/**
474 * scsi_setup_command_freelist - Setup the command freelist for a scsi host.
475 * @shost: host to allocate the freelist for.
476 *
477 * Description: The command freelist protects against system-wide out of memory
478 * deadlock by preallocating one SCSI command structure for each host, so the
479 * system can always write to a swap file on a device associated with that host.
480 *
481 * Returns: Nothing.
482 */
483int scsi_setup_command_freelist(struct Scsi_Host *shost)
484{
485 struct scsi_cmnd *cmd;
486 const gfp_t gfp_mask = shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL;
487
488 spin_lock_init(&shost->free_list_lock);
489 INIT_LIST_HEAD(&shost->free_list);
490
491 shost->cmd_pool = scsi_get_host_cmd_pool(gfp_mask);
492
493 if (!shost->cmd_pool)
494 return -ENOMEM;
495
496 /*
497 * Get one backup command for this host.
498 */
499 cmd = scsi_host_alloc_command(shost, gfp_mask);
500 if (!cmd) {
501 scsi_put_host_cmd_pool(gfp_mask);
502 shost->cmd_pool = NULL;
503 return -ENOMEM;
504 }
505 list_add(&cmd->list, &shost->free_list);
506 return 0;
507}
508
509/**
510 * scsi_destroy_command_freelist - Release the command freelist for a scsi host.
511 * @shost: host whose freelist is going to be destroyed
512 */
513void scsi_destroy_command_freelist(struct Scsi_Host *shost)
514{
515 /*
516 * If cmd_pool is NULL the free list was not initialized, so
517 * do not attempt to release resources.
518 */
519 if (!shost->cmd_pool)
520 return;
521
522 while (!list_empty(&shost->free_list)) {
523 struct scsi_cmnd *cmd;
524
525 cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
526 list_del_init(&cmd->list);
527 scsi_pool_free_command(shost->cmd_pool, cmd);
528 }
529 shost->cmd_pool = NULL;
530 scsi_put_host_cmd_pool(shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL);
531}
532
533#ifdef CONFIG_SCSI_LOGGING
534void scsi_log_send(struct scsi_cmnd *cmd)
535{
536 unsigned int level;
537
538 /*
539 * If ML QUEUE log level is greater than or equal to:
540 *
541 * 1: nothing (match completion)
542 *
543 * 2: log opcode + command of all commands
544 *
545 * 3: same as 2 plus dump cmd address
546 *
547 * 4: same as 3 plus dump extra junk
548 */
549 if (unlikely(scsi_logging_level)) {
550 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
551 SCSI_LOG_MLQUEUE_BITS);
552 if (level > 1) {
553 scmd_printk(KERN_INFO, cmd, "Send: ");
554 if (level > 2)
555 printk("0x%p ", cmd);
556 printk("\n");
557 scsi_print_command(cmd);
558 if (level > 3) {
559 printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
560 " queuecommand 0x%p\n",
561 scsi_sglist(cmd), scsi_bufflen(cmd),
562 cmd->device->host->hostt->queuecommand);
563
564 }
565 }
566 }
567}
568
569void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
570{
571 unsigned int level;
572
573 /*
574 * If ML COMPLETE log level is greater than or equal to:
575 *
576 * 1: log disposition, result, opcode + command, and conditionally
577 * sense data for failures or non SUCCESS dispositions.
578 *
579 * 2: same as 1 but for all command completions.
580 *
581 * 3: same as 2 plus dump cmd address
582 *
583 * 4: same as 3 plus dump extra junk
584 */
585 if (unlikely(scsi_logging_level)) {
586 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
587 SCSI_LOG_MLCOMPLETE_BITS);
588 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
589 (level > 1)) {
590 scmd_printk(KERN_INFO, cmd, "Done: ");
591 if (level > 2)
592 printk("0x%p ", cmd);
593 /*
594 * Dump truncated values, so we usually fit within
595 * 80 chars.
596 */
597 switch (disposition) {
598 case SUCCESS:
599 printk("SUCCESS\n");
600 break;
601 case NEEDS_RETRY:
602 printk("RETRY\n");
603 break;
604 case ADD_TO_MLQUEUE:
605 printk("MLQUEUE\n");
606 break;
607 case FAILED:
608 printk("FAILED\n");
609 break;
610 case TIMEOUT_ERROR:
611 /*
612 * If called via scsi_times_out.
613 */
614 printk("TIMEOUT\n");
615 break;
616 default:
617 printk("UNKNOWN\n");
618 }
619 scsi_print_result(cmd);
620 scsi_print_command(cmd);
621 if (status_byte(cmd->result) & CHECK_CONDITION)
622 scsi_print_sense("", cmd);
623 if (level > 3)
624 scmd_printk(KERN_INFO, cmd,
625 "scsi host busy %d failed %d\n",
626 cmd->device->host->host_busy,
627 cmd->device->host->host_failed);
628 }
629 }
630}
631#endif
632
633/**
634 * scsi_cmd_get_serial - Assign a serial number to a command
635 * @host: the scsi host
636 * @cmd: command to assign serial number to
637 *
638 * Description: a serial number identifies a request for error recovery
639 * and debugging purposes. Protected by the Host_Lock of host.
640 */
641void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
642{
643 cmd->serial_number = host->cmd_serial_number++;
644 if (cmd->serial_number == 0)
645 cmd->serial_number = host->cmd_serial_number++;
646}
647EXPORT_SYMBOL(scsi_cmd_get_serial);
648
649/**
650 * scsi_dispatch_command - Dispatch a command to the low-level driver.
651 * @cmd: command block we are dispatching.
652 *
653 * Return: nonzero return request was rejected and device's queue needs to be
654 * plugged.
655 */
656int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
657{
658 struct Scsi_Host *host = cmd->device->host;
659 unsigned long timeout;
660 int rtn = 0;
661
662 atomic_inc(&cmd->device->iorequest_cnt);
663
664 /* check if the device is still usable */
665 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
666 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
667 * returns an immediate error upwards, and signals
668 * that the device is no longer present */
669 cmd->result = DID_NO_CONNECT << 16;
670 scsi_done(cmd);
671 /* return 0 (because the command has been processed) */
672 goto out;
673 }
674
675 /* Check to see if the scsi lld made this device blocked. */
676 if (unlikely(scsi_device_blocked(cmd->device))) {
677 /*
678 * in blocked state, the command is just put back on
679 * the device queue. The suspend state has already
680 * blocked the queue so future requests should not
681 * occur until the device transitions out of the
682 * suspend state.
683 */
684
685 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
686
687 SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
688
689 /*
690 * NOTE: rtn is still zero here because we don't need the
691 * queue to be plugged on return (it's already stopped)
692 */
693 goto out;
694 }
695
696 /*
697 * If SCSI-2 or lower, store the LUN value in cmnd.
698 */
699 if (cmd->device->scsi_level <= SCSI_2 &&
700 cmd->device->scsi_level != SCSI_UNKNOWN) {
701 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
702 (cmd->device->lun << 5 & 0xe0);
703 }
704
705 /*
706 * We will wait MIN_RESET_DELAY clock ticks after the last reset so
707 * we can avoid the drive not being ready.
708 */
709 timeout = host->last_reset + MIN_RESET_DELAY;
710
711 if (host->resetting && time_before(jiffies, timeout)) {
712 int ticks_remaining = timeout - jiffies;
713 /*
714 * NOTE: This may be executed from within an interrupt
715 * handler! This is bad, but for now, it'll do. The irq
716 * level of the interrupt handler has been masked out by the
717 * platform dependent interrupt handling code already, so the
718 * sti() here will not cause another call to the SCSI host's
719 * interrupt handler (assuming there is one irq-level per
720 * host).
721 */
722 while (--ticks_remaining >= 0)
723 mdelay(1 + 999 / HZ);
724 host->resetting = 0;
725 }
726
727 scsi_log_send(cmd);
728
729 /*
730 * Before we queue this command, check if the command
731 * length exceeds what the host adapter can handle.
732 */
733 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
734 SCSI_LOG_MLQUEUE(3,
735 printk("queuecommand : command too long. "
736 "cdb_size=%d host->max_cmd_len=%d\n",
737 cmd->cmd_len, cmd->device->host->max_cmd_len));
738 cmd->result = (DID_ABORT << 16);
739
740 scsi_done(cmd);
741 goto out;
742 }
743
744 if (unlikely(host->shost_state == SHOST_DEL)) {
745 cmd->result = (DID_NO_CONNECT << 16);
746 scsi_done(cmd);
747 } else {
748 trace_scsi_dispatch_cmd_start(cmd);
749 cmd->scsi_done = scsi_done;
750 rtn = host->hostt->queuecommand(host, cmd);
751 }
752
753 if (rtn) {
754 trace_scsi_dispatch_cmd_error(cmd, rtn);
755 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
756 rtn != SCSI_MLQUEUE_TARGET_BUSY)
757 rtn = SCSI_MLQUEUE_HOST_BUSY;
758
759 scsi_queue_insert(cmd, rtn);
760
761 SCSI_LOG_MLQUEUE(3,
762 printk("queuecommand : request rejected\n"));
763 }
764
765 out:
766 SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
767 return rtn;
768}
769
770/**
771 * scsi_done - Enqueue the finished SCSI command into the done queue.
772 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
773 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
774 *
775 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
776 * which regains ownership of the SCSI command (de facto) from a LLDD, and
777 * enqueues the command to the done queue for further processing.
778 *
779 * This is the producer of the done queue who enqueues at the tail.
780 *
781 * This function is interrupt context safe.
782 */
783static void scsi_done(struct scsi_cmnd *cmd)
784{
785 trace_scsi_dispatch_cmd_done(cmd);
786 blk_complete_request(cmd->request);
787}
788
789/**
790 * scsi_finish_command - cleanup and pass command back to upper layer
791 * @cmd: the command
792 *
793 * Description: Pass command off to upper layer for finishing of I/O
794 * request, waking processes that are waiting on results,
795 * etc.
796 */
797void scsi_finish_command(struct scsi_cmnd *cmd)
798{
799 struct scsi_device *sdev = cmd->device;
800 struct scsi_target *starget = scsi_target(sdev);
801 struct Scsi_Host *shost = sdev->host;
802 struct scsi_driver *drv;
803 unsigned int good_bytes;
804
805 scsi_device_unbusy(sdev);
806
807 /*
808 * Clear the flags which say that the device/host is no longer
809 * capable of accepting new commands. These are set in scsi_queue.c
810 * for both the queue full condition on a device, and for a
811 * host full condition on the host.
812 *
813 * XXX(hch): What about locking?
814 */
815 shost->host_blocked = 0;
816 starget->target_blocked = 0;
817 sdev->device_blocked = 0;
818
819 /*
820 * If we have valid sense information, then some kind of recovery
821 * must have taken place. Make a note of this.
822 */
823 if (SCSI_SENSE_VALID(cmd))
824 cmd->result |= (DRIVER_SENSE << 24);
825
826 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
827 "Notifying upper driver of completion "
828 "(result %x)\n", cmd->result));
829
830 good_bytes = scsi_bufflen(cmd);
831 if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
832 int old_good_bytes = good_bytes;
833 drv = scsi_cmd_to_driver(cmd);
834 if (drv->done)
835 good_bytes = drv->done(cmd);
836 /*
837 * USB may not give sense identifying bad sector and
838 * simply return a residue instead, so subtract off the
839 * residue if drv->done() error processing indicates no
840 * change to the completion length.
841 */
842 if (good_bytes == old_good_bytes)
843 good_bytes -= scsi_get_resid(cmd);
844 }
845 scsi_io_completion(cmd, good_bytes);
846}
847EXPORT_SYMBOL(scsi_finish_command);
848
849/**
850 * scsi_adjust_queue_depth - Let low level drivers change a device's queue depth
851 * @sdev: SCSI Device in question
852 * @tagged: Do we use tagged queueing (non-0) or do we treat
853 * this device as an untagged device (0)
854 * @tags: Number of tags allowed if tagged queueing enabled,
855 * or number of commands the low level driver can
856 * queue up in non-tagged mode (as per cmd_per_lun).
857 *
858 * Returns: Nothing
859 *
860 * Lock Status: None held on entry
861 *
862 * Notes: Low level drivers may call this at any time and we will do
863 * the right thing depending on whether or not the device is
864 * currently active and whether or not it even has the
865 * command blocks built yet.
866 */
867void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
868{
869 unsigned long flags;
870
871 /*
872 * refuse to set tagged depth to an unworkable size
873 */
874 if (tags <= 0)
875 return;
876
877 spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
878
879 /*
880 * Check to see if the queue is managed by the block layer.
881 * If it is, and we fail to adjust the depth, exit.
882 *
883 * Do not resize the tag map if it is a host wide share bqt,
884 * because the size should be the hosts's can_queue. If there
885 * is more IO than the LLD's can_queue (so there are not enuogh
886 * tags) request_fn's host queue ready check will handle it.
887 */
888 if (!sdev->host->bqt) {
889 if (blk_queue_tagged(sdev->request_queue) &&
890 blk_queue_resize_tags(sdev->request_queue, tags) != 0)
891 goto out;
892 }
893
894 sdev->queue_depth = tags;
895 switch (tagged) {
896 case MSG_ORDERED_TAG:
897 sdev->ordered_tags = 1;
898 sdev->simple_tags = 1;
899 break;
900 case MSG_SIMPLE_TAG:
901 sdev->ordered_tags = 0;
902 sdev->simple_tags = 1;
903 break;
904 default:
905 sdev_printk(KERN_WARNING, sdev,
906 "scsi_adjust_queue_depth, bad queue type, "
907 "disabled\n");
908 case 0:
909 sdev->ordered_tags = sdev->simple_tags = 0;
910 sdev->queue_depth = tags;
911 break;
912 }
913 out:
914 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
915}
916EXPORT_SYMBOL(scsi_adjust_queue_depth);
917
918/**
919 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
920 * @sdev: SCSI Device in question
921 * @depth: Current number of outstanding SCSI commands on this device,
922 * not counting the one returned as QUEUE_FULL.
923 *
924 * Description: This function will track successive QUEUE_FULL events on a
925 * specific SCSI device to determine if and when there is a
926 * need to adjust the queue depth on the device.
927 *
928 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
929 * -1 - Drop back to untagged operation using host->cmd_per_lun
930 * as the untagged command depth
931 *
932 * Lock Status: None held on entry
933 *
934 * Notes: Low level drivers may call this at any time and we will do
935 * "The Right Thing." We are interrupt context safe.
936 */
937int scsi_track_queue_full(struct scsi_device *sdev, int depth)
938{
939
940 /*
941 * Don't let QUEUE_FULLs on the same
942 * jiffies count, they could all be from
943 * same event.
944 */
945 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
946 return 0;
947
948 sdev->last_queue_full_time = jiffies;
949 if (sdev->last_queue_full_depth != depth) {
950 sdev->last_queue_full_count = 1;
951 sdev->last_queue_full_depth = depth;
952 } else {
953 sdev->last_queue_full_count++;
954 }
955
956 if (sdev->last_queue_full_count <= 10)
957 return 0;
958 if (sdev->last_queue_full_depth < 8) {
959 /* Drop back to untagged */
960 scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
961 return -1;
962 }
963
964 if (sdev->ordered_tags)
965 scsi_adjust_queue_depth(sdev, MSG_ORDERED_TAG, depth);
966 else
967 scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
968 return depth;
969}
970EXPORT_SYMBOL(scsi_track_queue_full);
971
972/**
973 * scsi_vpd_inquiry - Request a device provide us with a VPD page
974 * @sdev: The device to ask
975 * @buffer: Where to put the result
976 * @page: Which Vital Product Data to return
977 * @len: The length of the buffer
978 *
979 * This is an internal helper function. You probably want to use
980 * scsi_get_vpd_page instead.
981 *
982 * Returns 0 on success or a negative error number.
983 */
984static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
985 u8 page, unsigned len)
986{
987 int result;
988 unsigned char cmd[16];
989
990 cmd[0] = INQUIRY;
991 cmd[1] = 1; /* EVPD */
992 cmd[2] = page;
993 cmd[3] = len >> 8;
994 cmd[4] = len & 0xff;
995 cmd[5] = 0; /* Control byte */
996
997 /*
998 * I'm not convinced we need to try quite this hard to get VPD, but
999 * all the existing users tried this hard.
1000 */
1001 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
1002 len, NULL, 30 * HZ, 3, NULL);
1003 if (result)
1004 return result;
1005
1006 /* Sanity check that we got the page back that we asked for */
1007 if (buffer[1] != page)
1008 return -EIO;
1009
1010 return 0;
1011}
1012
1013/**
1014 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
1015 * @sdev: The device to ask
1016 * @page: Which Vital Product Data to return
1017 * @buf: where to store the VPD
1018 * @buf_len: number of bytes in the VPD buffer area
1019 *
1020 * SCSI devices may optionally supply Vital Product Data. Each 'page'
1021 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
1022 * If the device supports this VPD page, this routine returns a pointer
1023 * to a buffer containing the data from that page. The caller is
1024 * responsible for calling kfree() on this pointer when it is no longer
1025 * needed. If we cannot retrieve the VPD page this routine returns %NULL.
1026 */
1027int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
1028 int buf_len)
1029{
1030 int i, result;
1031
1032 /* Ask for all the pages supported by this device */
1033 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len);
1034 if (result)
1035 goto fail;
1036
1037 /* If the user actually wanted this page, we can skip the rest */
1038 if (page == 0)
1039 return 0;
1040
1041 for (i = 0; i < min((int)buf[3], buf_len - 4); i++)
1042 if (buf[i + 4] == page)
1043 goto found;
1044
1045 if (i < buf[3] && i >= buf_len - 4)
1046 /* ran off the end of the buffer, give us benefit of doubt */
1047 goto found;
1048 /* The device claims it doesn't support the requested page */
1049 goto fail;
1050
1051 found:
1052 result = scsi_vpd_inquiry(sdev, buf, page, buf_len);
1053 if (result)
1054 goto fail;
1055
1056 return 0;
1057
1058 fail:
1059 return -EINVAL;
1060}
1061EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
1062
1063/**
1064 * scsi_device_get - get an additional reference to a scsi_device
1065 * @sdev: device to get a reference to
1066 *
1067 * Description: Gets a reference to the scsi_device and increments the use count
1068 * of the underlying LLDD module. You must hold host_lock of the
1069 * parent Scsi_Host or already have a reference when calling this.
1070 */
1071int scsi_device_get(struct scsi_device *sdev)
1072{
1073 if (sdev->sdev_state == SDEV_DEL)
1074 return -ENXIO;
1075 if (!get_device(&sdev->sdev_gendev))
1076 return -ENXIO;
1077 /* We can fail this if we're doing SCSI operations
1078 * from module exit (like cache flush) */
1079 try_module_get(sdev->host->hostt->module);
1080
1081 return 0;
1082}
1083EXPORT_SYMBOL(scsi_device_get);
1084
1085/**
1086 * scsi_device_put - release a reference to a scsi_device
1087 * @sdev: device to release a reference on.
1088 *
1089 * Description: Release a reference to the scsi_device and decrements the use
1090 * count of the underlying LLDD module. The device is freed once the last
1091 * user vanishes.
1092 */
1093void scsi_device_put(struct scsi_device *sdev)
1094{
1095#ifdef CONFIG_MODULE_UNLOAD
1096 struct module *module = sdev->host->hostt->module;
1097
1098 /* The module refcount will be zero if scsi_device_get()
1099 * was called from a module removal routine */
1100 if (module && module_refcount(module) != 0)
1101 module_put(module);
1102#endif
1103 put_device(&sdev->sdev_gendev);
1104}
1105EXPORT_SYMBOL(scsi_device_put);
1106
1107/* helper for shost_for_each_device, see that for documentation */
1108struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
1109 struct scsi_device *prev)
1110{
1111 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
1112 struct scsi_device *next = NULL;
1113 unsigned long flags;
1114
1115 spin_lock_irqsave(shost->host_lock, flags);
1116 while (list->next != &shost->__devices) {
1117 next = list_entry(list->next, struct scsi_device, siblings);
1118 /* skip devices that we can't get a reference to */
1119 if (!scsi_device_get(next))
1120 break;
1121 next = NULL;
1122 list = list->next;
1123 }
1124 spin_unlock_irqrestore(shost->host_lock, flags);
1125
1126 if (prev)
1127 scsi_device_put(prev);
1128 return next;
1129}
1130EXPORT_SYMBOL(__scsi_iterate_devices);
1131
1132/**
1133 * starget_for_each_device - helper to walk all devices of a target
1134 * @starget: target whose devices we want to iterate over.
1135 * @data: Opaque passed to each function call.
1136 * @fn: Function to call on each device
1137 *
1138 * This traverses over each device of @starget. The devices have
1139 * a reference that must be released by scsi_host_put when breaking
1140 * out of the loop.
1141 */
1142void starget_for_each_device(struct scsi_target *starget, void *data,
1143 void (*fn)(struct scsi_device *, void *))
1144{
1145 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1146 struct scsi_device *sdev;
1147
1148 shost_for_each_device(sdev, shost) {
1149 if ((sdev->channel == starget->channel) &&
1150 (sdev->id == starget->id))
1151 fn(sdev, data);
1152 }
1153}
1154EXPORT_SYMBOL(starget_for_each_device);
1155
1156/**
1157 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
1158 * @starget: target whose devices we want to iterate over.
1159 * @data: parameter for callback @fn()
1160 * @fn: callback function that is invoked for each device
1161 *
1162 * This traverses over each device of @starget. It does _not_
1163 * take a reference on the scsi_device, so the whole loop must be
1164 * protected by shost->host_lock.
1165 *
1166 * Note: The only reason why drivers would want to use this is because
1167 * they need to access the device list in irq context. Otherwise you
1168 * really want to use starget_for_each_device instead.
1169 **/
1170void __starget_for_each_device(struct scsi_target *starget, void *data,
1171 void (*fn)(struct scsi_device *, void *))
1172{
1173 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1174 struct scsi_device *sdev;
1175
1176 __shost_for_each_device(sdev, shost) {
1177 if ((sdev->channel == starget->channel) &&
1178 (sdev->id == starget->id))
1179 fn(sdev, data);
1180 }
1181}
1182EXPORT_SYMBOL(__starget_for_each_device);
1183
1184/**
1185 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
1186 * @starget: SCSI target pointer
1187 * @lun: SCSI Logical Unit Number
1188 *
1189 * Description: Looks up the scsi_device with the specified @lun for a given
1190 * @starget. The returned scsi_device does not have an additional
1191 * reference. You must hold the host's host_lock over this call and
1192 * any access to the returned scsi_device. A scsi_device in state
1193 * SDEV_DEL is skipped.
1194 *
1195 * Note: The only reason why drivers should use this is because
1196 * they need to access the device list in irq context. Otherwise you
1197 * really want to use scsi_device_lookup_by_target instead.
1198 **/
1199struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
1200 uint lun)
1201{
1202 struct scsi_device *sdev;
1203
1204 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
1205 if (sdev->sdev_state == SDEV_DEL)
1206 continue;
1207 if (sdev->lun ==lun)
1208 return sdev;
1209 }
1210
1211 return NULL;
1212}
1213EXPORT_SYMBOL(__scsi_device_lookup_by_target);
1214
1215/**
1216 * scsi_device_lookup_by_target - find a device given the target
1217 * @starget: SCSI target pointer
1218 * @lun: SCSI Logical Unit Number
1219 *
1220 * Description: Looks up the scsi_device with the specified @lun for a given
1221 * @starget. The returned scsi_device has an additional reference that
1222 * needs to be released with scsi_device_put once you're done with it.
1223 **/
1224struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
1225 uint lun)
1226{
1227 struct scsi_device *sdev;
1228 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1229 unsigned long flags;
1230
1231 spin_lock_irqsave(shost->host_lock, flags);
1232 sdev = __scsi_device_lookup_by_target(starget, lun);
1233 if (sdev && scsi_device_get(sdev))
1234 sdev = NULL;
1235 spin_unlock_irqrestore(shost->host_lock, flags);
1236
1237 return sdev;
1238}
1239EXPORT_SYMBOL(scsi_device_lookup_by_target);
1240
1241/**
1242 * __scsi_device_lookup - find a device given the host (UNLOCKED)
1243 * @shost: SCSI host pointer
1244 * @channel: SCSI channel (zero if only one channel)
1245 * @id: SCSI target number (physical unit number)
1246 * @lun: SCSI Logical Unit Number
1247 *
1248 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1249 * for a given host. The returned scsi_device does not have an additional
1250 * reference. You must hold the host's host_lock over this call and any access
1251 * to the returned scsi_device.
1252 *
1253 * Note: The only reason why drivers would want to use this is because
1254 * they need to access the device list in irq context. Otherwise you
1255 * really want to use scsi_device_lookup instead.
1256 **/
1257struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
1258 uint channel, uint id, uint lun)
1259{
1260 struct scsi_device *sdev;
1261
1262 list_for_each_entry(sdev, &shost->__devices, siblings) {
1263 if (sdev->channel == channel && sdev->id == id &&
1264 sdev->lun ==lun)
1265 return sdev;
1266 }
1267
1268 return NULL;
1269}
1270EXPORT_SYMBOL(__scsi_device_lookup);
1271
1272/**
1273 * scsi_device_lookup - find a device given the host
1274 * @shost: SCSI host pointer
1275 * @channel: SCSI channel (zero if only one channel)
1276 * @id: SCSI target number (physical unit number)
1277 * @lun: SCSI Logical Unit Number
1278 *
1279 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1280 * for a given host. The returned scsi_device has an additional reference that
1281 * needs to be released with scsi_device_put once you're done with it.
1282 **/
1283struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1284 uint channel, uint id, uint lun)
1285{
1286 struct scsi_device *sdev;
1287 unsigned long flags;
1288
1289 spin_lock_irqsave(shost->host_lock, flags);
1290 sdev = __scsi_device_lookup(shost, channel, id, lun);
1291 if (sdev && scsi_device_get(sdev))
1292 sdev = NULL;
1293 spin_unlock_irqrestore(shost->host_lock, flags);
1294
1295 return sdev;
1296}
1297EXPORT_SYMBOL(scsi_device_lookup);
1298
1299MODULE_DESCRIPTION("SCSI core");
1300MODULE_LICENSE("GPL");
1301
1302module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1303MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1304
1305static int __init init_scsi(void)
1306{
1307 int error;
1308
1309 error = scsi_init_queue();
1310 if (error)
1311 return error;
1312 error = scsi_init_procfs();
1313 if (error)
1314 goto cleanup_queue;
1315 error = scsi_init_devinfo();
1316 if (error)
1317 goto cleanup_procfs;
1318 error = scsi_init_hosts();
1319 if (error)
1320 goto cleanup_devlist;
1321 error = scsi_init_sysctl();
1322 if (error)
1323 goto cleanup_hosts;
1324 error = scsi_sysfs_register();
1325 if (error)
1326 goto cleanup_sysctl;
1327
1328 scsi_netlink_init();
1329
1330 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1331 return 0;
1332
1333cleanup_sysctl:
1334 scsi_exit_sysctl();
1335cleanup_hosts:
1336 scsi_exit_hosts();
1337cleanup_devlist:
1338 scsi_exit_devinfo();
1339cleanup_procfs:
1340 scsi_exit_procfs();
1341cleanup_queue:
1342 scsi_exit_queue();
1343 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1344 -error);
1345 return error;
1346}
1347
1348static void __exit exit_scsi(void)
1349{
1350 scsi_netlink_exit();
1351 scsi_sysfs_unregister();
1352 scsi_exit_sysctl();
1353 scsi_exit_hosts();
1354 scsi_exit_devinfo();
1355 scsi_exit_procfs();
1356 scsi_exit_queue();
1357}
1358
1359subsys_initcall(init_scsi);
1360module_exit(exit_scsi);