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1/*
2 * scsi.c Copyright (C) 1992 Drew Eckhardt
3 * Copyright (C) 1993, 1994, 1995, 1999 Eric Youngdale
4 * Copyright (C) 2002, 2003 Christoph Hellwig
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/* 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
96 */
97static 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 ",
117};
118
119/**
120 * scsi_device_type - Return 17 char string indicating device type.
121 * @type: type number to look up
122 */
123
124const char * scsi_device_type(unsigned type)
125{
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];
133}
134
135EXPORT_SYMBOL(scsi_device_type);
136
137struct 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;
145};
146
147static 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,
151};
152
153static 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,
158};
159
160static DEFINE_MUTEX(host_cmd_pool_mutex);
161
162/**
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
166 *
167 * Returns a fully allocated command (with the allied sense buffer) or
168 * NULL on failure
169 */
170static struct scsi_cmnd *
171scsi_pool_alloc_command(struct scsi_host_cmd_pool *pool, gfp_t gfp_mask)
172{
173 struct scsi_cmnd *cmd;
174
175 cmd = kmem_cache_zalloc(pool->cmd_slab, gfp_mask | pool->gfp_mask);
176 if (!cmd)
177 return NULL;
178
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;
184 }
185
186 return cmd;
187}
188
189/**
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
193 *
194 * the command must previously have been allocated by
195 * scsi_pool_alloc_command.
196 */
197static void
198scsi_pool_free_command(struct scsi_host_cmd_pool *pool,
199 struct scsi_cmnd *cmd)
200{
201 if (cmd->prot_sdb)
202 kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb);
203
204 kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
205 kmem_cache_free(pool->cmd_slab, cmd);
206}
207
208/**
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
212 *
213 * Returns a fully allocated command with sense buffer and protection
214 * data buffer (where applicable) or NULL on failure
215 */
216static struct scsi_cmnd *
217scsi_host_alloc_command(struct Scsi_Host *shost, gfp_t gfp_mask)
218{
219 struct scsi_cmnd *cmd;
220
221 cmd = scsi_pool_alloc_command(shost->cmd_pool, gfp_mask);
222 if (!cmd)
223 return NULL;
224
225 if (scsi_host_get_prot(shost) >= SHOST_DIX_TYPE0_PROTECTION) {
226 cmd->prot_sdb = kmem_cache_zalloc(scsi_sdb_cache, gfp_mask);
227
228 if (!cmd->prot_sdb) {
229 scsi_pool_free_command(shost->cmd_pool, cmd);
230 return NULL;
231 }
232 }
233
234 return cmd;
235}
236
237/**
238 * __scsi_get_command - Allocate a struct scsi_cmnd
239 * @shost: host to transmit command
240 * @gfp_mask: allocation mask
241 *
242 * Description: allocate a struct scsi_cmd from host's slab, recycling from the
243 * host's free_list if necessary.
244 */
245struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
246{
247 struct scsi_cmnd *cmd = scsi_host_alloc_command(shost, gfp_mask);
248
249 if (unlikely(!cmd)) {
250 unsigned long flags;
251
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);
257 }
258 spin_unlock_irqrestore(&shost->free_list_lock, flags);
259
260 if (cmd) {
261 void *buf, *prot;
262
263 buf = cmd->sense_buffer;
264 prot = cmd->prot_sdb;
265
266 memset(cmd, 0, sizeof(*cmd));
267
268 cmd->sense_buffer = buf;
269 cmd->prot_sdb = prot;
270 }
271 }
272
273 return cmd;
274}
275EXPORT_SYMBOL_GPL(__scsi_get_command);
276
277/**
278 * scsi_get_command - Allocate and setup a scsi command block
279 * @dev: parent scsi device
280 * @gfp_mask: allocator flags
281 *
282 * Returns: The allocated scsi command structure.
283 */
284struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
285{
286 struct scsi_cmnd *cmd;
287
288 /* Bail if we can't get a reference to the device */
289 if (!get_device(&dev->sdev_gendev))
290 return NULL;
291
292 cmd = __scsi_get_command(dev->host, gfp_mask);
293
294 if (likely(cmd != NULL)) {
295 unsigned long flags;
296
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);
305
306 return cmd;
307}
308EXPORT_SYMBOL(scsi_get_command);
309
310/**
311 * __scsi_put_command - Free a struct scsi_cmnd
312 * @shost: dev->host
313 * @cmd: Command to free
314 * @dev: parent scsi device
315 */
316void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd,
317 struct device *dev)
318{
319 unsigned long flags;
320
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;
326 }
327 spin_unlock_irqrestore(&shost->free_list_lock, flags);
328
329 if (likely(cmd != NULL))
330 scsi_pool_free_command(shost->cmd_pool, cmd);
331
332 put_device(dev);
333}
334EXPORT_SYMBOL(__scsi_put_command);
335
336/**
337 * scsi_put_command - Free a scsi command block
338 * @cmd: command block to free
339 *
340 * Returns: Nothing.
341 *
342 * Notes: The command must not belong to any lists.
343 */
344void scsi_put_command(struct scsi_cmnd *cmd)
345{
346 struct scsi_device *sdev = cmd->device;
347 unsigned long flags;
348
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);
354
355 __scsi_put_command(cmd->device->host, cmd, &sdev->sdev_gendev);
356}
357EXPORT_SYMBOL(scsi_put_command);
358
359static struct scsi_host_cmd_pool *scsi_get_host_cmd_pool(gfp_t gfp_mask)
360{
361 struct scsi_host_cmd_pool *retval = NULL, *pool;
362 /*
363 * Select a command slab for this host and create it if not
364 * yet existent.
365 */
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;
375
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;
382 }
383 }
384
385 pool->users++;
386 retval = pool;
387 fail:
388 mutex_unlock(&host_cmd_pool_mutex);
389 return retval;
390}
391
392static void scsi_put_host_cmd_pool(gfp_t gfp_mask)
393{
394 struct scsi_host_cmd_pool *pool;
395
396 mutex_lock(&host_cmd_pool_mutex);
397 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
398 &scsi_cmd_pool;
399 /*
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
403 */
404 BUG_ON(pool->users == 0);
405
406 if (!--pool->users) {
407 kmem_cache_destroy(pool->cmd_slab);
408 kmem_cache_destroy(pool->sense_slab);
409 }
410 mutex_unlock(&host_cmd_pool_mutex);
411}
412
413/**
414 * scsi_allocate_command - get a fully allocated SCSI command
415 * @gfp_mask: allocation mask
416 *
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.
422 *
423 * This function should *only* be used by drivers that need a static
424 * command allocation at start of day for internal functions.
425 */
426struct scsi_cmnd *scsi_allocate_command(gfp_t gfp_mask)
427{
428 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
429
430 if (!pool)
431 return NULL;
432
433 return scsi_pool_alloc_command(pool, gfp_mask);
434}
435EXPORT_SYMBOL(scsi_allocate_command);
436
437/**
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
441 *
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.
445 */
446void scsi_free_command(gfp_t gfp_mask, struct scsi_cmnd *cmd)
447{
448 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
449
450 /*
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
455 */
456 BUG_ON(!pool);
457
458 scsi_pool_free_command(pool, cmd);
459 /*
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
463 */
464 scsi_put_host_cmd_pool(gfp_mask);
465 scsi_put_host_cmd_pool(gfp_mask);
466}
467EXPORT_SYMBOL(scsi_free_command);
468
469/**
470 * scsi_setup_command_freelist - Setup the command freelist for a scsi host.
471 * @shost: host to allocate the freelist for.
472 *
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.
476 *
477 * Returns: Nothing.
478 */
479int scsi_setup_command_freelist(struct Scsi_Host *shost)
480{
481 struct scsi_cmnd *cmd;
482 const gfp_t gfp_mask = shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL;
483
484 spin_lock_init(&shost->free_list_lock);
485 INIT_LIST_HEAD(&shost->free_list);
486
487 shost->cmd_pool = scsi_get_host_cmd_pool(gfp_mask);
488
489 if (!shost->cmd_pool)
490 return -ENOMEM;
491
492 /*
493 * Get one backup command for this host.
494 */
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;
500 }
501 list_add(&cmd->list, &shost->free_list);
502 return 0;
503}
504
505/**
506 * scsi_destroy_command_freelist - Release the command freelist for a scsi host.
507 * @shost: host whose freelist is going to be destroyed
508 */
509void scsi_destroy_command_freelist(struct Scsi_Host *shost)
510{
511 /*
512 * If cmd_pool is NULL the free list was not initialized, so
513 * do not attempt to release resources.
514 */
515 if (!shost->cmd_pool)
516 return;
517
518 while (!list_empty(&shost->free_list)) {
519 struct scsi_cmnd *cmd;
520
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);
524 }
525 shost->cmd_pool = NULL;
526 scsi_put_host_cmd_pool(shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL);
527}
528
529#ifdef CONFIG_SCSI_LOGGING
530void scsi_log_send(struct scsi_cmnd *cmd)
531{
532 unsigned int level;
533
534 /*
535 * If ML QUEUE log level is greater than or equal to:
536 *
537 * 1: nothing (match completion)
538 *
539 * 2: log opcode + command of all commands
540 *
541 * 3: same as 2 plus dump cmd address
542 *
543 * 4: same as 3 plus dump extra junk
544 */
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);
559
560 }
561 }
562 }
563}
564
565void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
566{
567 unsigned int level;
568
569 /*
570 * If ML COMPLETE log level is greater than or equal to:
571 *
572 * 1: log disposition, result, opcode + command, and conditionally
573 * sense data for failures or non SUCCESS dispositions.
574 *
575 * 2: same as 1 but for all command completions.
576 *
577 * 3: same as 2 plus dump cmd address
578 *
579 * 4: same as 3 plus dump extra junk
580 */
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);
589 /*
590 * Dump truncated values, so we usually fit within
591 * 80 chars.
592 */
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:
607 /*
608 * If called via scsi_times_out.
609 */
610 printk("TIMEOUT\n");
611 break;
612 default:
613 printk("UNKNOWN\n");
614 }
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);
624 }
625 }
626}
627#endif
628
629/**
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
633 *
634 * Description: a serial number identifies a request for error recovery
635 * and debugging purposes. Protected by the Host_Lock of host.
636 */
637void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
638{
639 cmd->serial_number = host->cmd_serial_number++;
640 if (cmd->serial_number == 0)
641 cmd->serial_number = host->cmd_serial_number++;
642}
643EXPORT_SYMBOL(scsi_cmd_get_serial);
644
645/**
646 * scsi_dispatch_command - Dispatch a command to the low-level driver.
647 * @cmd: command block we are dispatching.
648 *
649 * Return: nonzero return request was rejected and device's queue needs to be
650 * plugged.
651 */
652int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
653{
654 struct Scsi_Host *host = cmd->device->host;
655 unsigned long timeout;
656 int rtn = 0;
657
658 atomic_inc(&cmd->device->iorequest_cnt);
659
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;
669 }
670
671 /* Check to see if the scsi lld made this device blocked. */
672 if (unlikely(scsi_device_blocked(cmd->device))) {
673 /*
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.
679 */
680
681 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
682
683 SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
684
685 /*
686 * NOTE: rtn is still zero here because we don't need the
687 * queue to be plugged on return (it's already stopped)
688 */
689 goto out;
690 }
691
692 /*
693 * If SCSI-2 or lower, store the LUN value in cmnd.
694 */
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);
699 }
700
701 /*
702 * We will wait MIN_RESET_DELAY clock ticks after the last reset so
703 * we can avoid the drive not being ready.
704 */
705 timeout = host->last_reset + MIN_RESET_DELAY;
706
707 if (host->resetting && time_before(jiffies, timeout)) {
708 int ticks_remaining = timeout - jiffies;
709 /*
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).
717 */
718 while (--ticks_remaining >= 0)
719 mdelay(1 + 999 / HZ);
720 host->resetting = 0;
721 }
722
723 scsi_log_send(cmd);
724
725 /*
726 * Before we queue this command, check if the command
727 * length exceeds what the host adapter can handle.
728 */
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);
735
736 scsi_done(cmd);
737 goto out;
738 }
739
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);
747 }
748
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;
754
755 scsi_queue_insert(cmd, rtn);
756
757 SCSI_LOG_MLQUEUE(3,
758 printk("queuecommand : request rejected\n"));
759 }
760
761 out:
762 SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
763 return rtn;
764}
765
766/**
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.
770 *
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.
774 *
775 * This is the producer of the done queue who enqueues at the tail.
776 *
777 * This function is interrupt context safe.
778 */
779static void scsi_done(struct scsi_cmnd *cmd)
780{
781 trace_scsi_dispatch_cmd_done(cmd);
782 blk_complete_request(cmd->request);
783}
784
785/* Move this to a header if it becomes more generally useful */
786static struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd)
787{
788 return *(struct scsi_driver **)cmd->request->rq_disk->private_data;
789}
790
791/**
792 * scsi_finish_command - cleanup and pass command back to upper layer
793 * @cmd: the command
794 *
795 * Description: Pass command off to upper layer for finishing of I/O
796 * request, waking processes that are waiting on results,
797 * etc.
798 */
799void scsi_finish_command(struct scsi_cmnd *cmd)
800{
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;
806
807 scsi_device_unbusy(sdev);
808
809 /*
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.
814 *
815 * XXX(hch): What about locking?
816 */
817 shost->host_blocked = 0;
818 starget->target_blocked = 0;
819 sdev->device_blocked = 0;
820
821 /*
822 * If we have valid sense information, then some kind of recovery
823 * must have taken place. Make a note of this.
824 */
825 if (SCSI_SENSE_VALID(cmd))
826 cmd->result |= (DRIVER_SENSE << 24);
827
828 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
829 "Notifying upper driver of completion "
830 "(result %x)\n", cmd->result));
831
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);
838 /*
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.
843 */
844 if (good_bytes == old_good_bytes)
845 good_bytes -= scsi_get_resid(cmd);
846 }
847 scsi_io_completion(cmd, good_bytes);
848}
849EXPORT_SYMBOL(scsi_finish_command);
850
851/**
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).
859 *
860 * Returns: Nothing
861 *
862 * Lock Status: None held on entry
863 *
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.
868 */
869void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
870{
871 unsigned long flags;
872
873 /*
874 * refuse to set tagged depth to an unworkable size
875 */
876 if (tags <= 0)
877 return;
878
879 spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
880
881 /*
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.
884 *
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.
889 */
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;
894 }
895
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;
914 }
915 out:
916 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
917}
918EXPORT_SYMBOL(scsi_adjust_queue_depth);
919
920/**
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.
925 *
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.
929 *
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
933 *
934 * Lock Status: None held on entry
935 *
936 * Notes: Low level drivers may call this at any time and we will do
937 * "The Right Thing." We are interrupt context safe.
938 */
939int scsi_track_queue_full(struct scsi_device *sdev, int depth)
940{
941
942 /*
943 * Don't let QUEUE_FULLs on the same
944 * jiffies count, they could all be from
945 * same event.
946 */
947 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
948 return 0;
949
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++;
956 }
957
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;
964 }
965
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;
971}
972EXPORT_SYMBOL(scsi_track_queue_full);
973
974/**
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
980 *
981 * This is an internal helper function. You probably want to use
982 * scsi_get_vpd_page instead.
983 *
984 * Returns 0 on success or a negative error number.
985 */
986static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
987 u8 page, unsigned len)
988{
989 int result;
990 unsigned char cmd[16];
991
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 */
998
999 /*
1000 * I'm not convinced we need to try quite this hard to get VPD, but
1001 * all the existing users tried this hard.
1002 */
1003 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
1004 len, NULL, 30 * HZ, 3, NULL);
1005 if (result)
1006 return result;
1007
1008 /* Sanity check that we got the page back that we asked for */
1009 if (buffer[1] != page)
1010 return -EIO;
1011
1012 return 0;
1013}
1014
1015/**
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
1021 *
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.
1028 */
1029int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
1030 int buf_len)
1031{
1032 int i, result;
1033
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;
1038
1039 /* If the user actually wanted this page, we can skip the rest */
1040 if (page == 0)
1041 return 0;
1042
1043 for (i = 0; i < min((int)buf[3], buf_len - 4); i++)
1044 if (buf[i + 4] == page)
1045 goto found;
1046
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;
1052
1053 found:
1054 result = scsi_vpd_inquiry(sdev, buf, page, buf_len);
1055 if (result)
1056 goto fail;
1057
1058 return 0;
1059
1060 fail:
1061 return -EINVAL;
1062}
1063EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
1064
1065/**
1066 * scsi_device_get - get an additional reference to a scsi_device
1067 * @sdev: device to get a reference to
1068 *
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.
1072 */
1073int scsi_device_get(struct scsi_device *sdev)
1074{
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);
1082
1083 return 0;
1084}
1085EXPORT_SYMBOL(scsi_device_get);
1086
1087/**
1088 * scsi_device_put - release a reference to a scsi_device
1089 * @sdev: device to release a reference on.
1090 *
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.
1094 */
1095void scsi_device_put(struct scsi_device *sdev)
1096{
1097#ifdef CONFIG_MODULE_UNLOAD
1098 struct module *module = sdev->host->hostt->module;
1099
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);
1106}
1107EXPORT_SYMBOL(scsi_device_put);
1108
1109/* helper for shost_for_each_device, see that for documentation */
1110struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
1111 struct scsi_device *prev)
1112{
1113 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
1114 struct scsi_device *next = NULL;
1115 unsigned long flags;
1116
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;
1125 }
1126 spin_unlock_irqrestore(shost->host_lock, flags);
1127
1128 if (prev)
1129 scsi_device_put(prev);
1130 return next;
1131}
1132EXPORT_SYMBOL(__scsi_iterate_devices);
1133
1134/**
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
1139 *
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.
1143 */
1144void starget_for_each_device(struct scsi_target *starget, void *data,
1145 void (*fn)(struct scsi_device *, void *))
1146{
1147 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1148 struct scsi_device *sdev;
1149
1150 shost_for_each_device(sdev, shost) {
1151 if ((sdev->channel == starget->channel) &&
1152 (sdev->id == starget->id))
1153 fn(sdev, data);
1154 }
1155}
1156EXPORT_SYMBOL(starget_for_each_device);
1157
1158/**
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
1163 *
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.
1167 *
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.
1171 **/
1172void __starget_for_each_device(struct scsi_target *starget, void *data,
1173 void (*fn)(struct scsi_device *, void *))
1174{
1175 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1176 struct scsi_device *sdev;
1177
1178 __shost_for_each_device(sdev, shost) {
1179 if ((sdev->channel == starget->channel) &&
1180 (sdev->id == starget->id))
1181 fn(sdev, data);
1182 }
1183}
1184EXPORT_SYMBOL(__starget_for_each_device);
1185
1186/**
1187 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
1188 * @starget: SCSI target pointer
1189 * @lun: SCSI Logical Unit Number
1190 *
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.
1196 *
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.
1200 **/
1201struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
1202 uint lun)
1203{
1204 struct scsi_device *sdev;
1205
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;
1211 }
1212
1213 return NULL;
1214}
1215EXPORT_SYMBOL(__scsi_device_lookup_by_target);
1216
1217/**
1218 * scsi_device_lookup_by_target - find a device given the target
1219 * @starget: SCSI target pointer
1220 * @lun: SCSI Logical Unit Number
1221 *
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.
1225 **/
1226struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
1227 uint lun)
1228{
1229 struct scsi_device *sdev;
1230 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1231 unsigned long flags;
1232
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);
1238
1239 return sdev;
1240}
1241EXPORT_SYMBOL(scsi_device_lookup_by_target);
1242
1243/**
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
1249 *
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.
1254 *
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.
1258 **/
1259struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
1260 uint channel, uint id, uint lun)
1261{
1262 struct scsi_device *sdev;
1263
1264 list_for_each_entry(sdev, &shost->__devices, siblings) {
1265 if (sdev->channel == channel && sdev->id == id &&
1266 sdev->lun ==lun)
1267 return sdev;
1268 }
1269
1270 return NULL;
1271}
1272EXPORT_SYMBOL(__scsi_device_lookup);
1273
1274/**
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
1280 *
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.
1284 **/
1285struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1286 uint channel, uint id, uint lun)
1287{
1288 struct scsi_device *sdev;
1289 unsigned long flags;
1290
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);
1296
1297 return sdev;
1298}
1299EXPORT_SYMBOL(scsi_device_lookup);
1300
1301MODULE_DESCRIPTION("SCSI core");
1302MODULE_LICENSE("GPL");
1303
1304module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1305MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1306
1307static int __init init_scsi(void)
1308{
1309 int error;
1310
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;
1329
1330 scsi_netlink_init();
1331
1332 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1333 return 0;
1334
1335cleanup_sysctl:
1336 scsi_exit_sysctl();
1337cleanup_hosts:
1338 scsi_exit_hosts();
1339cleanup_devlist:
1340 scsi_exit_devinfo();
1341cleanup_procfs:
1342 scsi_exit_procfs();
1343cleanup_queue:
1344 scsi_exit_queue();
1345 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1346 -error);
1347 return error;
1348}
1349
1350static void __exit exit_scsi(void)
1351{
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();
1359}
1360
1361subsys_initcall(init_scsi);
1362module_exit(exit_scsi);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * scsi.c Copyright (C) 1992 Drew Eckhardt
4 * Copyright (C) 1993, 1994, 1995, 1999 Eric Youngdale
5 * Copyright (C) 2002, 2003 Christoph Hellwig
6 *
7 * generic mid-level SCSI driver
8 * Initial versions: Drew Eckhardt
9 * Subsequent revisions: Eric Youngdale
10 *
11 * <drew@colorado.edu>
12 *
13 * Bug correction thanks go to :
14 * Rik Faith <faith@cs.unc.edu>
15 * Tommy Thorn <tthorn>
16 * Thomas Wuensche <tw@fgb1.fgb.mw.tu-muenchen.de>
17 *
18 * Modified by Eric Youngdale eric@andante.org or ericy@gnu.ai.mit.edu to
19 * add scatter-gather, multiple outstanding request, and other
20 * enhancements.
21 *
22 * Native multichannel, wide scsi, /proc/scsi and hot plugging
23 * support added by Michael Neuffer <mike@i-connect.net>
24 *
25 * Added request_module("scsi_hostadapter") for kerneld:
26 * (Put an "alias scsi_hostadapter your_hostadapter" in /etc/modprobe.conf)
27 * Bjorn Ekwall <bj0rn@blox.se>
28 * (changed to kmod)
29 *
30 * Major improvements to the timeout, abort, and reset processing,
31 * as well as performance modifications for large queue depths by
32 * Leonard N. Zubkoff <lnz@dandelion.com>
33 *
34 * Converted cli() code to spinlocks, Ingo Molnar
35 *
36 * Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
37 *
38 * out_of_space hacks, D. Gilbert (dpg) 990608
39 */
40
41#include <linux/module.h>
42#include <linux/moduleparam.h>
43#include <linux/kernel.h>
44#include <linux/timer.h>
45#include <linux/string.h>
46#include <linux/slab.h>
47#include <linux/blkdev.h>
48#include <linux/delay.h>
49#include <linux/init.h>
50#include <linux/completion.h>
51#include <linux/unistd.h>
52#include <linux/spinlock.h>
53#include <linux/kmod.h>
54#include <linux/interrupt.h>
55#include <linux/notifier.h>
56#include <linux/cpu.h>
57#include <linux/mutex.h>
58#include <linux/async.h>
59#include <asm/unaligned.h>
60
61#include <scsi/scsi.h>
62#include <scsi/scsi_cmnd.h>
63#include <scsi/scsi_dbg.h>
64#include <scsi/scsi_device.h>
65#include <scsi/scsi_driver.h>
66#include <scsi/scsi_eh.h>
67#include <scsi/scsi_host.h>
68#include <scsi/scsi_tcq.h>
69
70#include "scsi_priv.h"
71#include "scsi_logging.h"
72
73#define CREATE_TRACE_POINTS
74#include <trace/events/scsi.h>
75
76/*
77 * Definitions and constants.
78 */
79
80/*
81 * Note - the initial logging level can be set here to log events at boot time.
82 * After the system is up, you may enable logging via the /proc interface.
83 */
84unsigned int scsi_logging_level;
85#if defined(CONFIG_SCSI_LOGGING)
86EXPORT_SYMBOL(scsi_logging_level);
87#endif
88
89/*
90 * Domain for asynchronous system resume operations. It is marked 'exclusive'
91 * to avoid being included in the async_synchronize_full() that is invoked by
92 * dpm_resume().
93 */
94ASYNC_DOMAIN_EXCLUSIVE(scsi_sd_pm_domain);
95EXPORT_SYMBOL(scsi_sd_pm_domain);
96
97/**
98 * scsi_put_command - Free a scsi command block
99 * @cmd: command block to free
100 *
101 * Returns: Nothing.
102 *
103 * Notes: The command must not belong to any lists.
104 */
105void scsi_put_command(struct scsi_cmnd *cmd)
106{
107 scsi_del_cmd_from_list(cmd);
108 BUG_ON(delayed_work_pending(&cmd->abort_work));
109}
110
111#ifdef CONFIG_SCSI_LOGGING
112void scsi_log_send(struct scsi_cmnd *cmd)
113{
114 unsigned int level;
115
116 /*
117 * If ML QUEUE log level is greater than or equal to:
118 *
119 * 1: nothing (match completion)
120 *
121 * 2: log opcode + command of all commands + cmd address
122 *
123 * 3: same as 2
124 *
125 * 4: same as 3
126 */
127 if (unlikely(scsi_logging_level)) {
128 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
129 SCSI_LOG_MLQUEUE_BITS);
130 if (level > 1) {
131 scmd_printk(KERN_INFO, cmd,
132 "Send: scmd 0x%p\n", cmd);
133 scsi_print_command(cmd);
134 }
135 }
136}
137
138void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
139{
140 unsigned int level;
141
142 /*
143 * If ML COMPLETE log level is greater than or equal to:
144 *
145 * 1: log disposition, result, opcode + command, and conditionally
146 * sense data for failures or non SUCCESS dispositions.
147 *
148 * 2: same as 1 but for all command completions.
149 *
150 * 3: same as 2
151 *
152 * 4: same as 3 plus dump extra junk
153 */
154 if (unlikely(scsi_logging_level)) {
155 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
156 SCSI_LOG_MLCOMPLETE_BITS);
157 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
158 (level > 1)) {
159 scsi_print_result(cmd, "Done", disposition);
160 scsi_print_command(cmd);
161 if (status_byte(cmd->result) == CHECK_CONDITION)
162 scsi_print_sense(cmd);
163 if (level > 3)
164 scmd_printk(KERN_INFO, cmd,
165 "scsi host busy %d failed %d\n",
166 scsi_host_busy(cmd->device->host),
167 cmd->device->host->host_failed);
168 }
169 }
170}
171#endif
172
173/**
174 * scsi_finish_command - cleanup and pass command back to upper layer
175 * @cmd: the command
176 *
177 * Description: Pass command off to upper layer for finishing of I/O
178 * request, waking processes that are waiting on results,
179 * etc.
180 */
181void scsi_finish_command(struct scsi_cmnd *cmd)
182{
183 struct scsi_device *sdev = cmd->device;
184 struct scsi_target *starget = scsi_target(sdev);
185 struct Scsi_Host *shost = sdev->host;
186 struct scsi_driver *drv;
187 unsigned int good_bytes;
188
189 scsi_device_unbusy(sdev);
190
191 /*
192 * Clear the flags that say that the device/target/host is no longer
193 * capable of accepting new commands.
194 */
195 if (atomic_read(&shost->host_blocked))
196 atomic_set(&shost->host_blocked, 0);
197 if (atomic_read(&starget->target_blocked))
198 atomic_set(&starget->target_blocked, 0);
199 if (atomic_read(&sdev->device_blocked))
200 atomic_set(&sdev->device_blocked, 0);
201
202 /*
203 * If we have valid sense information, then some kind of recovery
204 * must have taken place. Make a note of this.
205 */
206 if (SCSI_SENSE_VALID(cmd))
207 cmd->result |= (DRIVER_SENSE << 24);
208
209 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
210 "Notifying upper driver of completion "
211 "(result %x)\n", cmd->result));
212
213 good_bytes = scsi_bufflen(cmd);
214 if (!blk_rq_is_passthrough(cmd->request)) {
215 int old_good_bytes = good_bytes;
216 drv = scsi_cmd_to_driver(cmd);
217 if (drv->done)
218 good_bytes = drv->done(cmd);
219 /*
220 * USB may not give sense identifying bad sector and
221 * simply return a residue instead, so subtract off the
222 * residue if drv->done() error processing indicates no
223 * change to the completion length.
224 */
225 if (good_bytes == old_good_bytes)
226 good_bytes -= scsi_get_resid(cmd);
227 }
228 scsi_io_completion(cmd, good_bytes);
229}
230
231/**
232 * scsi_change_queue_depth - change a device's queue depth
233 * @sdev: SCSI Device in question
234 * @depth: number of commands allowed to be queued to the driver
235 *
236 * Sets the device queue depth and returns the new value.
237 */
238int scsi_change_queue_depth(struct scsi_device *sdev, int depth)
239{
240 if (depth > 0) {
241 sdev->queue_depth = depth;
242 wmb();
243 }
244
245 if (sdev->request_queue)
246 blk_set_queue_depth(sdev->request_queue, depth);
247
248 return sdev->queue_depth;
249}
250EXPORT_SYMBOL(scsi_change_queue_depth);
251
252/**
253 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
254 * @sdev: SCSI Device in question
255 * @depth: Current number of outstanding SCSI commands on this device,
256 * not counting the one returned as QUEUE_FULL.
257 *
258 * Description: This function will track successive QUEUE_FULL events on a
259 * specific SCSI device to determine if and when there is a
260 * need to adjust the queue depth on the device.
261 *
262 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
263 * -1 - Drop back to untagged operation using host->cmd_per_lun
264 * as the untagged command depth
265 *
266 * Lock Status: None held on entry
267 *
268 * Notes: Low level drivers may call this at any time and we will do
269 * "The Right Thing." We are interrupt context safe.
270 */
271int scsi_track_queue_full(struct scsi_device *sdev, int depth)
272{
273
274 /*
275 * Don't let QUEUE_FULLs on the same
276 * jiffies count, they could all be from
277 * same event.
278 */
279 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
280 return 0;
281
282 sdev->last_queue_full_time = jiffies;
283 if (sdev->last_queue_full_depth != depth) {
284 sdev->last_queue_full_count = 1;
285 sdev->last_queue_full_depth = depth;
286 } else {
287 sdev->last_queue_full_count++;
288 }
289
290 if (sdev->last_queue_full_count <= 10)
291 return 0;
292
293 return scsi_change_queue_depth(sdev, depth);
294}
295EXPORT_SYMBOL(scsi_track_queue_full);
296
297/**
298 * scsi_vpd_inquiry - Request a device provide us with a VPD page
299 * @sdev: The device to ask
300 * @buffer: Where to put the result
301 * @page: Which Vital Product Data to return
302 * @len: The length of the buffer
303 *
304 * This is an internal helper function. You probably want to use
305 * scsi_get_vpd_page instead.
306 *
307 * Returns size of the vpd page on success or a negative error number.
308 */
309static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
310 u8 page, unsigned len)
311{
312 int result;
313 unsigned char cmd[16];
314
315 if (len < 4)
316 return -EINVAL;
317
318 cmd[0] = INQUIRY;
319 cmd[1] = 1; /* EVPD */
320 cmd[2] = page;
321 cmd[3] = len >> 8;
322 cmd[4] = len & 0xff;
323 cmd[5] = 0; /* Control byte */
324
325 /*
326 * I'm not convinced we need to try quite this hard to get VPD, but
327 * all the existing users tried this hard.
328 */
329 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
330 len, NULL, 30 * HZ, 3, NULL);
331 if (result)
332 return -EIO;
333
334 /* Sanity check that we got the page back that we asked for */
335 if (buffer[1] != page)
336 return -EIO;
337
338 return get_unaligned_be16(&buffer[2]) + 4;
339}
340
341/**
342 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
343 * @sdev: The device to ask
344 * @page: Which Vital Product Data to return
345 * @buf: where to store the VPD
346 * @buf_len: number of bytes in the VPD buffer area
347 *
348 * SCSI devices may optionally supply Vital Product Data. Each 'page'
349 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
350 * If the device supports this VPD page, this routine returns a pointer
351 * to a buffer containing the data from that page. The caller is
352 * responsible for calling kfree() on this pointer when it is no longer
353 * needed. If we cannot retrieve the VPD page this routine returns %NULL.
354 */
355int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
356 int buf_len)
357{
358 int i, result;
359
360 if (sdev->skip_vpd_pages)
361 goto fail;
362
363 /* Ask for all the pages supported by this device */
364 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len);
365 if (result < 4)
366 goto fail;
367
368 /* If the user actually wanted this page, we can skip the rest */
369 if (page == 0)
370 return 0;
371
372 for (i = 4; i < min(result, buf_len); i++)
373 if (buf[i] == page)
374 goto found;
375
376 if (i < result && i >= buf_len)
377 /* ran off the end of the buffer, give us benefit of doubt */
378 goto found;
379 /* The device claims it doesn't support the requested page */
380 goto fail;
381
382 found:
383 result = scsi_vpd_inquiry(sdev, buf, page, buf_len);
384 if (result < 0)
385 goto fail;
386
387 return 0;
388
389 fail:
390 return -EINVAL;
391}
392EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
393
394/**
395 * scsi_get_vpd_buf - Get Vital Product Data from a SCSI device
396 * @sdev: The device to ask
397 * @page: Which Vital Product Data to return
398 *
399 * Returns %NULL upon failure.
400 */
401static struct scsi_vpd *scsi_get_vpd_buf(struct scsi_device *sdev, u8 page)
402{
403 struct scsi_vpd *vpd_buf;
404 int vpd_len = SCSI_VPD_PG_LEN, result;
405
406retry_pg:
407 vpd_buf = kmalloc(sizeof(*vpd_buf) + vpd_len, GFP_KERNEL);
408 if (!vpd_buf)
409 return NULL;
410
411 result = scsi_vpd_inquiry(sdev, vpd_buf->data, page, vpd_len);
412 if (result < 0) {
413 kfree(vpd_buf);
414 return NULL;
415 }
416 if (result > vpd_len) {
417 vpd_len = result;
418 kfree(vpd_buf);
419 goto retry_pg;
420 }
421
422 vpd_buf->len = result;
423
424 return vpd_buf;
425}
426
427static void scsi_update_vpd_page(struct scsi_device *sdev, u8 page,
428 struct scsi_vpd __rcu **sdev_vpd_buf)
429{
430 struct scsi_vpd *vpd_buf;
431
432 vpd_buf = scsi_get_vpd_buf(sdev, page);
433 if (!vpd_buf)
434 return;
435
436 mutex_lock(&sdev->inquiry_mutex);
437 rcu_swap_protected(*sdev_vpd_buf, vpd_buf,
438 lockdep_is_held(&sdev->inquiry_mutex));
439 mutex_unlock(&sdev->inquiry_mutex);
440
441 if (vpd_buf)
442 kfree_rcu(vpd_buf, rcu);
443}
444
445/**
446 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure
447 * @sdev: The device to ask
448 *
449 * Attach the 'Device Identification' VPD page (0x83) and the
450 * 'Unit Serial Number' VPD page (0x80) to a SCSI device
451 * structure. This information can be used to identify the device
452 * uniquely.
453 */
454void scsi_attach_vpd(struct scsi_device *sdev)
455{
456 int i;
457 struct scsi_vpd *vpd_buf;
458
459 if (!scsi_device_supports_vpd(sdev))
460 return;
461
462 /* Ask for all the pages supported by this device */
463 vpd_buf = scsi_get_vpd_buf(sdev, 0);
464 if (!vpd_buf)
465 return;
466
467 for (i = 4; i < vpd_buf->len; i++) {
468 if (vpd_buf->data[i] == 0x80)
469 scsi_update_vpd_page(sdev, 0x80, &sdev->vpd_pg80);
470 if (vpd_buf->data[i] == 0x83)
471 scsi_update_vpd_page(sdev, 0x83, &sdev->vpd_pg83);
472 }
473 kfree(vpd_buf);
474}
475
476/**
477 * scsi_report_opcode - Find out if a given command opcode is supported
478 * @sdev: scsi device to query
479 * @buffer: scratch buffer (must be at least 20 bytes long)
480 * @len: length of buffer
481 * @opcode: opcode for command to look up
482 *
483 * Uses the REPORT SUPPORTED OPERATION CODES to look up the given
484 * opcode. Returns -EINVAL if RSOC fails, 0 if the command opcode is
485 * unsupported and 1 if the device claims to support the command.
486 */
487int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,
488 unsigned int len, unsigned char opcode)
489{
490 unsigned char cmd[16];
491 struct scsi_sense_hdr sshdr;
492 int result;
493
494 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3)
495 return -EINVAL;
496
497 memset(cmd, 0, 16);
498 cmd[0] = MAINTENANCE_IN;
499 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES;
500 cmd[2] = 1; /* One command format */
501 cmd[3] = opcode;
502 put_unaligned_be32(len, &cmd[6]);
503 memset(buffer, 0, len);
504
505 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
506 &sshdr, 30 * HZ, 3, NULL);
507
508 if (result && scsi_sense_valid(&sshdr) &&
509 sshdr.sense_key == ILLEGAL_REQUEST &&
510 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00)
511 return -EINVAL;
512
513 if ((buffer[1] & 3) == 3) /* Command supported */
514 return 1;
515
516 return 0;
517}
518EXPORT_SYMBOL(scsi_report_opcode);
519
520/**
521 * scsi_device_get - get an additional reference to a scsi_device
522 * @sdev: device to get a reference to
523 *
524 * Description: Gets a reference to the scsi_device and increments the use count
525 * of the underlying LLDD module. You must hold host_lock of the
526 * parent Scsi_Host or already have a reference when calling this.
527 *
528 * This will fail if a device is deleted or cancelled, or when the LLD module
529 * is in the process of being unloaded.
530 */
531int scsi_device_get(struct scsi_device *sdev)
532{
533 if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL)
534 goto fail;
535 if (!get_device(&sdev->sdev_gendev))
536 goto fail;
537 if (!try_module_get(sdev->host->hostt->module))
538 goto fail_put_device;
539 return 0;
540
541fail_put_device:
542 put_device(&sdev->sdev_gendev);
543fail:
544 return -ENXIO;
545}
546EXPORT_SYMBOL(scsi_device_get);
547
548/**
549 * scsi_device_put - release a reference to a scsi_device
550 * @sdev: device to release a reference on.
551 *
552 * Description: Release a reference to the scsi_device and decrements the use
553 * count of the underlying LLDD module. The device is freed once the last
554 * user vanishes.
555 */
556void scsi_device_put(struct scsi_device *sdev)
557{
558 module_put(sdev->host->hostt->module);
559 put_device(&sdev->sdev_gendev);
560}
561EXPORT_SYMBOL(scsi_device_put);
562
563/* helper for shost_for_each_device, see that for documentation */
564struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
565 struct scsi_device *prev)
566{
567 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
568 struct scsi_device *next = NULL;
569 unsigned long flags;
570
571 spin_lock_irqsave(shost->host_lock, flags);
572 while (list->next != &shost->__devices) {
573 next = list_entry(list->next, struct scsi_device, siblings);
574 /* skip devices that we can't get a reference to */
575 if (!scsi_device_get(next))
576 break;
577 next = NULL;
578 list = list->next;
579 }
580 spin_unlock_irqrestore(shost->host_lock, flags);
581
582 if (prev)
583 scsi_device_put(prev);
584 return next;
585}
586EXPORT_SYMBOL(__scsi_iterate_devices);
587
588/**
589 * starget_for_each_device - helper to walk all devices of a target
590 * @starget: target whose devices we want to iterate over.
591 * @data: Opaque passed to each function call.
592 * @fn: Function to call on each device
593 *
594 * This traverses over each device of @starget. The devices have
595 * a reference that must be released by scsi_host_put when breaking
596 * out of the loop.
597 */
598void starget_for_each_device(struct scsi_target *starget, void *data,
599 void (*fn)(struct scsi_device *, void *))
600{
601 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
602 struct scsi_device *sdev;
603
604 shost_for_each_device(sdev, shost) {
605 if ((sdev->channel == starget->channel) &&
606 (sdev->id == starget->id))
607 fn(sdev, data);
608 }
609}
610EXPORT_SYMBOL(starget_for_each_device);
611
612/**
613 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
614 * @starget: target whose devices we want to iterate over.
615 * @data: parameter for callback @fn()
616 * @fn: callback function that is invoked for each device
617 *
618 * This traverses over each device of @starget. It does _not_
619 * take a reference on the scsi_device, so the whole loop must be
620 * protected by shost->host_lock.
621 *
622 * Note: The only reason why drivers would want to use this is because
623 * they need to access the device list in irq context. Otherwise you
624 * really want to use starget_for_each_device instead.
625 **/
626void __starget_for_each_device(struct scsi_target *starget, void *data,
627 void (*fn)(struct scsi_device *, void *))
628{
629 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
630 struct scsi_device *sdev;
631
632 __shost_for_each_device(sdev, shost) {
633 if ((sdev->channel == starget->channel) &&
634 (sdev->id == starget->id))
635 fn(sdev, data);
636 }
637}
638EXPORT_SYMBOL(__starget_for_each_device);
639
640/**
641 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
642 * @starget: SCSI target pointer
643 * @lun: SCSI Logical Unit Number
644 *
645 * Description: Looks up the scsi_device with the specified @lun for a given
646 * @starget. The returned scsi_device does not have an additional
647 * reference. You must hold the host's host_lock over this call and
648 * any access to the returned scsi_device. A scsi_device in state
649 * SDEV_DEL is skipped.
650 *
651 * Note: The only reason why drivers should use this is because
652 * they need to access the device list in irq context. Otherwise you
653 * really want to use scsi_device_lookup_by_target instead.
654 **/
655struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
656 u64 lun)
657{
658 struct scsi_device *sdev;
659
660 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
661 if (sdev->sdev_state == SDEV_DEL)
662 continue;
663 if (sdev->lun ==lun)
664 return sdev;
665 }
666
667 return NULL;
668}
669EXPORT_SYMBOL(__scsi_device_lookup_by_target);
670
671/**
672 * scsi_device_lookup_by_target - find a device given the target
673 * @starget: SCSI target pointer
674 * @lun: SCSI Logical Unit Number
675 *
676 * Description: Looks up the scsi_device with the specified @lun for a given
677 * @starget. The returned scsi_device has an additional reference that
678 * needs to be released with scsi_device_put once you're done with it.
679 **/
680struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
681 u64 lun)
682{
683 struct scsi_device *sdev;
684 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
685 unsigned long flags;
686
687 spin_lock_irqsave(shost->host_lock, flags);
688 sdev = __scsi_device_lookup_by_target(starget, lun);
689 if (sdev && scsi_device_get(sdev))
690 sdev = NULL;
691 spin_unlock_irqrestore(shost->host_lock, flags);
692
693 return sdev;
694}
695EXPORT_SYMBOL(scsi_device_lookup_by_target);
696
697/**
698 * __scsi_device_lookup - find a device given the host (UNLOCKED)
699 * @shost: SCSI host pointer
700 * @channel: SCSI channel (zero if only one channel)
701 * @id: SCSI target number (physical unit number)
702 * @lun: SCSI Logical Unit Number
703 *
704 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
705 * for a given host. The returned scsi_device does not have an additional
706 * reference. You must hold the host's host_lock over this call and any access
707 * to the returned scsi_device.
708 *
709 * Note: The only reason why drivers would want to use this is because
710 * they need to access the device list in irq context. Otherwise you
711 * really want to use scsi_device_lookup instead.
712 **/
713struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
714 uint channel, uint id, u64 lun)
715{
716 struct scsi_device *sdev;
717
718 list_for_each_entry(sdev, &shost->__devices, siblings) {
719 if (sdev->sdev_state == SDEV_DEL)
720 continue;
721 if (sdev->channel == channel && sdev->id == id &&
722 sdev->lun ==lun)
723 return sdev;
724 }
725
726 return NULL;
727}
728EXPORT_SYMBOL(__scsi_device_lookup);
729
730/**
731 * scsi_device_lookup - find a device given the host
732 * @shost: SCSI host pointer
733 * @channel: SCSI channel (zero if only one channel)
734 * @id: SCSI target number (physical unit number)
735 * @lun: SCSI Logical Unit Number
736 *
737 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
738 * for a given host. The returned scsi_device has an additional reference that
739 * needs to be released with scsi_device_put once you're done with it.
740 **/
741struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
742 uint channel, uint id, u64 lun)
743{
744 struct scsi_device *sdev;
745 unsigned long flags;
746
747 spin_lock_irqsave(shost->host_lock, flags);
748 sdev = __scsi_device_lookup(shost, channel, id, lun);
749 if (sdev && scsi_device_get(sdev))
750 sdev = NULL;
751 spin_unlock_irqrestore(shost->host_lock, flags);
752
753 return sdev;
754}
755EXPORT_SYMBOL(scsi_device_lookup);
756
757MODULE_DESCRIPTION("SCSI core");
758MODULE_LICENSE("GPL");
759
760module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
761MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
762
763/* This should go away in the future, it doesn't do anything anymore */
764bool scsi_use_blk_mq = true;
765module_param_named(use_blk_mq, scsi_use_blk_mq, bool, S_IWUSR | S_IRUGO);
766
767static int __init init_scsi(void)
768{
769 int error;
770
771 error = scsi_init_queue();
772 if (error)
773 return error;
774 error = scsi_init_procfs();
775 if (error)
776 goto cleanup_queue;
777 error = scsi_init_devinfo();
778 if (error)
779 goto cleanup_procfs;
780 error = scsi_init_hosts();
781 if (error)
782 goto cleanup_devlist;
783 error = scsi_init_sysctl();
784 if (error)
785 goto cleanup_hosts;
786 error = scsi_sysfs_register();
787 if (error)
788 goto cleanup_sysctl;
789
790 scsi_netlink_init();
791
792 printk(KERN_NOTICE "SCSI subsystem initialized\n");
793 return 0;
794
795cleanup_sysctl:
796 scsi_exit_sysctl();
797cleanup_hosts:
798 scsi_exit_hosts();
799cleanup_devlist:
800 scsi_exit_devinfo();
801cleanup_procfs:
802 scsi_exit_procfs();
803cleanup_queue:
804 scsi_exit_queue();
805 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
806 -error);
807 return error;
808}
809
810static void __exit exit_scsi(void)
811{
812 scsi_netlink_exit();
813 scsi_sysfs_unregister();
814 scsi_exit_sysctl();
815 scsi_exit_hosts();
816 scsi_exit_devinfo();
817 scsi_exit_procfs();
818 scsi_exit_queue();
819}
820
821subsys_initcall(init_scsi);
822module_exit(exit_scsi);