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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/*
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
75/*
76 * Definitions and constants.
77 */
78
79/*
80 * Note - the initial logging level can be set here to log events at boot time.
81 * After the system is up, you may enable logging via the /proc interface.
82 */
83unsigned int scsi_logging_level;
84#if defined(CONFIG_SCSI_LOGGING)
85EXPORT_SYMBOL(scsi_logging_level);
86#endif
87
88/* sd, scsi core and power management need to coordinate flushing async actions */
89ASYNC_DOMAIN(scsi_sd_probe_domain);
90EXPORT_SYMBOL(scsi_sd_probe_domain);
91
92/*
93 * Separate domain (from scsi_sd_probe_domain) to maximize the benefit of
94 * asynchronous system resume operations. It is marked 'exclusive' to avoid
95 * being included in the async_synchronize_full() that is invoked by
96 * dpm_resume()
97 */
98ASYNC_DOMAIN_EXCLUSIVE(scsi_sd_pm_domain);
99EXPORT_SYMBOL(scsi_sd_pm_domain);
100
101struct scsi_host_cmd_pool {
102 struct kmem_cache *cmd_slab;
103 struct kmem_cache *sense_slab;
104 unsigned int users;
105 char *cmd_name;
106 char *sense_name;
107 unsigned int slab_flags;
108 gfp_t gfp_mask;
109};
110
111static struct scsi_host_cmd_pool scsi_cmd_pool = {
112 .cmd_name = "scsi_cmd_cache",
113 .sense_name = "scsi_sense_cache",
114 .slab_flags = SLAB_HWCACHE_ALIGN,
115};
116
117static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
118 .cmd_name = "scsi_cmd_cache(DMA)",
119 .sense_name = "scsi_sense_cache(DMA)",
120 .slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA,
121 .gfp_mask = __GFP_DMA,
122};
123
124static DEFINE_MUTEX(host_cmd_pool_mutex);
125
126/**
127 * scsi_host_free_command - internal function to release a command
128 * @shost: host to free the command for
129 * @cmd: command to release
130 *
131 * the command must previously have been allocated by
132 * scsi_host_alloc_command.
133 */
134static void
135scsi_host_free_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
136{
137 struct scsi_host_cmd_pool *pool = shost->cmd_pool;
138
139 if (cmd->prot_sdb)
140 kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb);
141 kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
142 kmem_cache_free(pool->cmd_slab, cmd);
143}
144
145/**
146 * scsi_host_alloc_command - internal function to allocate command
147 * @shost: SCSI host whose pool to allocate from
148 * @gfp_mask: mask for the allocation
149 *
150 * Returns a fully allocated command with sense buffer and protection
151 * data buffer (where applicable) or NULL on failure
152 */
153static struct scsi_cmnd *
154scsi_host_alloc_command(struct Scsi_Host *shost, gfp_t gfp_mask)
155{
156 struct scsi_host_cmd_pool *pool = shost->cmd_pool;
157 struct scsi_cmnd *cmd;
158
159 cmd = kmem_cache_zalloc(pool->cmd_slab, gfp_mask | pool->gfp_mask);
160 if (!cmd)
161 goto fail;
162
163 cmd->sense_buffer = kmem_cache_alloc(pool->sense_slab,
164 gfp_mask | pool->gfp_mask);
165 if (!cmd->sense_buffer)
166 goto fail_free_cmd;
167
168 if (scsi_host_get_prot(shost) >= SHOST_DIX_TYPE0_PROTECTION) {
169 cmd->prot_sdb = kmem_cache_zalloc(scsi_sdb_cache, gfp_mask);
170 if (!cmd->prot_sdb)
171 goto fail_free_sense;
172 }
173
174 return cmd;
175
176fail_free_sense:
177 kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
178fail_free_cmd:
179 kmem_cache_free(pool->cmd_slab, cmd);
180fail:
181 return NULL;
182}
183
184/**
185 * __scsi_get_command - Allocate a struct scsi_cmnd
186 * @shost: host to transmit command
187 * @gfp_mask: allocation mask
188 *
189 * Description: allocate a struct scsi_cmd from host's slab, recycling from the
190 * host's free_list if necessary.
191 */
192static struct scsi_cmnd *
193__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
194{
195 struct scsi_cmnd *cmd = scsi_host_alloc_command(shost, gfp_mask);
196
197 if (unlikely(!cmd)) {
198 unsigned long flags;
199
200 spin_lock_irqsave(&shost->free_list_lock, flags);
201 if (likely(!list_empty(&shost->free_list))) {
202 cmd = list_entry(shost->free_list.next,
203 struct scsi_cmnd, list);
204 list_del_init(&cmd->list);
205 }
206 spin_unlock_irqrestore(&shost->free_list_lock, flags);
207
208 if (cmd) {
209 void *buf, *prot;
210
211 buf = cmd->sense_buffer;
212 prot = cmd->prot_sdb;
213
214 memset(cmd, 0, sizeof(*cmd));
215
216 cmd->sense_buffer = buf;
217 cmd->prot_sdb = prot;
218 }
219 }
220
221 return cmd;
222}
223
224/**
225 * scsi_get_command - Allocate and setup a scsi command block
226 * @dev: parent scsi device
227 * @gfp_mask: allocator flags
228 *
229 * Returns: The allocated scsi command structure.
230 */
231struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
232{
233 struct scsi_cmnd *cmd = __scsi_get_command(dev->host, gfp_mask);
234 unsigned long flags;
235
236 if (unlikely(cmd == NULL))
237 return NULL;
238
239 cmd->device = dev;
240 INIT_LIST_HEAD(&cmd->list);
241 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
242 spin_lock_irqsave(&dev->list_lock, flags);
243 list_add_tail(&cmd->list, &dev->cmd_list);
244 spin_unlock_irqrestore(&dev->list_lock, flags);
245 cmd->jiffies_at_alloc = jiffies;
246 return cmd;
247}
248
249/**
250 * __scsi_put_command - Free a struct scsi_cmnd
251 * @shost: dev->host
252 * @cmd: Command to free
253 */
254static void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
255{
256 unsigned long flags;
257
258 if (unlikely(list_empty(&shost->free_list))) {
259 spin_lock_irqsave(&shost->free_list_lock, flags);
260 if (list_empty(&shost->free_list)) {
261 list_add(&cmd->list, &shost->free_list);
262 cmd = NULL;
263 }
264 spin_unlock_irqrestore(&shost->free_list_lock, flags);
265 }
266
267 if (likely(cmd != NULL))
268 scsi_host_free_command(shost, cmd);
269}
270
271/**
272 * scsi_put_command - Free a scsi command block
273 * @cmd: command block to free
274 *
275 * Returns: Nothing.
276 *
277 * Notes: The command must not belong to any lists.
278 */
279void scsi_put_command(struct scsi_cmnd *cmd)
280{
281 unsigned long flags;
282
283 /* serious error if the command hasn't come from a device list */
284 spin_lock_irqsave(&cmd->device->list_lock, flags);
285 BUG_ON(list_empty(&cmd->list));
286 list_del_init(&cmd->list);
287 spin_unlock_irqrestore(&cmd->device->list_lock, flags);
288
289 BUG_ON(delayed_work_pending(&cmd->abort_work));
290
291 __scsi_put_command(cmd->device->host, cmd);
292}
293
294static struct scsi_host_cmd_pool *
295scsi_find_host_cmd_pool(struct Scsi_Host *shost)
296{
297 if (shost->hostt->cmd_size)
298 return shost->hostt->cmd_pool;
299 if (shost->unchecked_isa_dma)
300 return &scsi_cmd_dma_pool;
301 return &scsi_cmd_pool;
302}
303
304static void
305scsi_free_host_cmd_pool(struct scsi_host_cmd_pool *pool)
306{
307 kfree(pool->sense_name);
308 kfree(pool->cmd_name);
309 kfree(pool);
310}
311
312static struct scsi_host_cmd_pool *
313scsi_alloc_host_cmd_pool(struct Scsi_Host *shost)
314{
315 struct scsi_host_template *hostt = shost->hostt;
316 struct scsi_host_cmd_pool *pool;
317
318 pool = kzalloc(sizeof(*pool), GFP_KERNEL);
319 if (!pool)
320 return NULL;
321
322 pool->cmd_name = kasprintf(GFP_KERNEL, "%s_cmd", hostt->proc_name);
323 pool->sense_name = kasprintf(GFP_KERNEL, "%s_sense", hostt->proc_name);
324 if (!pool->cmd_name || !pool->sense_name) {
325 scsi_free_host_cmd_pool(pool);
326 return NULL;
327 }
328
329 pool->slab_flags = SLAB_HWCACHE_ALIGN;
330 if (shost->unchecked_isa_dma) {
331 pool->slab_flags |= SLAB_CACHE_DMA;
332 pool->gfp_mask = __GFP_DMA;
333 }
334
335 if (hostt->cmd_size)
336 hostt->cmd_pool = pool;
337
338 return pool;
339}
340
341static struct scsi_host_cmd_pool *
342scsi_get_host_cmd_pool(struct Scsi_Host *shost)
343{
344 struct scsi_host_template *hostt = shost->hostt;
345 struct scsi_host_cmd_pool *retval = NULL, *pool;
346 size_t cmd_size = sizeof(struct scsi_cmnd) + hostt->cmd_size;
347
348 /*
349 * Select a command slab for this host and create it if not
350 * yet existent.
351 */
352 mutex_lock(&host_cmd_pool_mutex);
353 pool = scsi_find_host_cmd_pool(shost);
354 if (!pool) {
355 pool = scsi_alloc_host_cmd_pool(shost);
356 if (!pool)
357 goto out;
358 }
359
360 if (!pool->users) {
361 pool->cmd_slab = kmem_cache_create(pool->cmd_name, cmd_size, 0,
362 pool->slab_flags, NULL);
363 if (!pool->cmd_slab)
364 goto out_free_pool;
365
366 pool->sense_slab = kmem_cache_create(pool->sense_name,
367 SCSI_SENSE_BUFFERSIZE, 0,
368 pool->slab_flags, NULL);
369 if (!pool->sense_slab)
370 goto out_free_slab;
371 }
372
373 pool->users++;
374 retval = pool;
375out:
376 mutex_unlock(&host_cmd_pool_mutex);
377 return retval;
378
379out_free_slab:
380 kmem_cache_destroy(pool->cmd_slab);
381out_free_pool:
382 if (hostt->cmd_size) {
383 scsi_free_host_cmd_pool(pool);
384 hostt->cmd_pool = NULL;
385 }
386 goto out;
387}
388
389static void scsi_put_host_cmd_pool(struct Scsi_Host *shost)
390{
391 struct scsi_host_template *hostt = shost->hostt;
392 struct scsi_host_cmd_pool *pool;
393
394 mutex_lock(&host_cmd_pool_mutex);
395 pool = scsi_find_host_cmd_pool(shost);
396
397 /*
398 * This may happen if a driver has a mismatched get and put
399 * of the command pool; the driver should be implicated in
400 * the stack trace
401 */
402 BUG_ON(pool->users == 0);
403
404 if (!--pool->users) {
405 kmem_cache_destroy(pool->cmd_slab);
406 kmem_cache_destroy(pool->sense_slab);
407 if (hostt->cmd_size) {
408 scsi_free_host_cmd_pool(pool);
409 hostt->cmd_pool = NULL;
410 }
411 }
412 mutex_unlock(&host_cmd_pool_mutex);
413}
414
415/**
416 * scsi_setup_command_freelist - Setup the command freelist for a scsi host.
417 * @shost: host to allocate the freelist for.
418 *
419 * Description: The command freelist protects against system-wide out of memory
420 * deadlock by preallocating one SCSI command structure for each host, so the
421 * system can always write to a swap file on a device associated with that host.
422 *
423 * Returns: Nothing.
424 */
425int scsi_setup_command_freelist(struct Scsi_Host *shost)
426{
427 const gfp_t gfp_mask = shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL;
428 struct scsi_cmnd *cmd;
429
430 spin_lock_init(&shost->free_list_lock);
431 INIT_LIST_HEAD(&shost->free_list);
432
433 shost->cmd_pool = scsi_get_host_cmd_pool(shost);
434 if (!shost->cmd_pool)
435 return -ENOMEM;
436
437 /*
438 * Get one backup command for this host.
439 */
440 cmd = scsi_host_alloc_command(shost, gfp_mask);
441 if (!cmd) {
442 scsi_put_host_cmd_pool(shost);
443 shost->cmd_pool = NULL;
444 return -ENOMEM;
445 }
446 list_add(&cmd->list, &shost->free_list);
447 return 0;
448}
449
450/**
451 * scsi_destroy_command_freelist - Release the command freelist for a scsi host.
452 * @shost: host whose freelist is going to be destroyed
453 */
454void scsi_destroy_command_freelist(struct Scsi_Host *shost)
455{
456 /*
457 * If cmd_pool is NULL the free list was not initialized, so
458 * do not attempt to release resources.
459 */
460 if (!shost->cmd_pool)
461 return;
462
463 while (!list_empty(&shost->free_list)) {
464 struct scsi_cmnd *cmd;
465
466 cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
467 list_del_init(&cmd->list);
468 scsi_host_free_command(shost, cmd);
469 }
470 shost->cmd_pool = NULL;
471 scsi_put_host_cmd_pool(shost);
472}
473
474#ifdef CONFIG_SCSI_LOGGING
475void scsi_log_send(struct scsi_cmnd *cmd)
476{
477 unsigned int level;
478
479 /*
480 * If ML QUEUE log level is greater than or equal to:
481 *
482 * 1: nothing (match completion)
483 *
484 * 2: log opcode + command of all commands + cmd address
485 *
486 * 3: same as 2
487 *
488 * 4: same as 3
489 */
490 if (unlikely(scsi_logging_level)) {
491 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
492 SCSI_LOG_MLQUEUE_BITS);
493 if (level > 1) {
494 scmd_printk(KERN_INFO, cmd,
495 "Send: scmd 0x%p\n", cmd);
496 scsi_print_command(cmd);
497 }
498 }
499}
500
501void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
502{
503 unsigned int level;
504
505 /*
506 * If ML COMPLETE log level is greater than or equal to:
507 *
508 * 1: log disposition, result, opcode + command, and conditionally
509 * sense data for failures or non SUCCESS dispositions.
510 *
511 * 2: same as 1 but for all command completions.
512 *
513 * 3: same as 2
514 *
515 * 4: same as 3 plus dump extra junk
516 */
517 if (unlikely(scsi_logging_level)) {
518 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
519 SCSI_LOG_MLCOMPLETE_BITS);
520 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
521 (level > 1)) {
522 scsi_print_result(cmd, "Done", disposition);
523 scsi_print_command(cmd);
524 if (status_byte(cmd->result) & CHECK_CONDITION)
525 scsi_print_sense(cmd);
526 if (level > 3)
527 scmd_printk(KERN_INFO, cmd,
528 "scsi host busy %d failed %d\n",
529 atomic_read(&cmd->device->host->host_busy),
530 cmd->device->host->host_failed);
531 }
532 }
533}
534#endif
535
536/**
537 * scsi_cmd_get_serial - Assign a serial number to a command
538 * @host: the scsi host
539 * @cmd: command to assign serial number to
540 *
541 * Description: a serial number identifies a request for error recovery
542 * and debugging purposes. Protected by the Host_Lock of host.
543 */
544void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
545{
546 cmd->serial_number = host->cmd_serial_number++;
547 if (cmd->serial_number == 0)
548 cmd->serial_number = host->cmd_serial_number++;
549}
550EXPORT_SYMBOL(scsi_cmd_get_serial);
551
552/**
553 * scsi_finish_command - cleanup and pass command back to upper layer
554 * @cmd: the command
555 *
556 * Description: Pass command off to upper layer for finishing of I/O
557 * request, waking processes that are waiting on results,
558 * etc.
559 */
560void scsi_finish_command(struct scsi_cmnd *cmd)
561{
562 struct scsi_device *sdev = cmd->device;
563 struct scsi_target *starget = scsi_target(sdev);
564 struct Scsi_Host *shost = sdev->host;
565 struct scsi_driver *drv;
566 unsigned int good_bytes;
567
568 scsi_device_unbusy(sdev);
569
570 /*
571 * Clear the flags that say that the device/target/host is no longer
572 * capable of accepting new commands.
573 */
574 if (atomic_read(&shost->host_blocked))
575 atomic_set(&shost->host_blocked, 0);
576 if (atomic_read(&starget->target_blocked))
577 atomic_set(&starget->target_blocked, 0);
578 if (atomic_read(&sdev->device_blocked))
579 atomic_set(&sdev->device_blocked, 0);
580
581 /*
582 * If we have valid sense information, then some kind of recovery
583 * must have taken place. Make a note of this.
584 */
585 if (SCSI_SENSE_VALID(cmd))
586 cmd->result |= (DRIVER_SENSE << 24);
587
588 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
589 "Notifying upper driver of completion "
590 "(result %x)\n", cmd->result));
591
592 good_bytes = scsi_bufflen(cmd);
593 if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
594 int old_good_bytes = good_bytes;
595 drv = scsi_cmd_to_driver(cmd);
596 if (drv->done)
597 good_bytes = drv->done(cmd);
598 /*
599 * USB may not give sense identifying bad sector and
600 * simply return a residue instead, so subtract off the
601 * residue if drv->done() error processing indicates no
602 * change to the completion length.
603 */
604 if (good_bytes == old_good_bytes)
605 good_bytes -= scsi_get_resid(cmd);
606 }
607 scsi_io_completion(cmd, good_bytes);
608}
609
610/**
611 * scsi_change_queue_depth - change a device's queue depth
612 * @sdev: SCSI Device in question
613 * @depth: number of commands allowed to be queued to the driver
614 *
615 * Sets the device queue depth and returns the new value.
616 */
617int scsi_change_queue_depth(struct scsi_device *sdev, int depth)
618{
619 if (depth > 0) {
620 sdev->queue_depth = depth;
621 wmb();
622 }
623
624 if (sdev->request_queue)
625 blk_set_queue_depth(sdev->request_queue, depth);
626
627 return sdev->queue_depth;
628}
629EXPORT_SYMBOL(scsi_change_queue_depth);
630
631/**
632 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
633 * @sdev: SCSI Device in question
634 * @depth: Current number of outstanding SCSI commands on this device,
635 * not counting the one returned as QUEUE_FULL.
636 *
637 * Description: This function will track successive QUEUE_FULL events on a
638 * specific SCSI device to determine if and when there is a
639 * need to adjust the queue depth on the device.
640 *
641 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
642 * -1 - Drop back to untagged operation using host->cmd_per_lun
643 * as the untagged command depth
644 *
645 * Lock Status: None held on entry
646 *
647 * Notes: Low level drivers may call this at any time and we will do
648 * "The Right Thing." We are interrupt context safe.
649 */
650int scsi_track_queue_full(struct scsi_device *sdev, int depth)
651{
652
653 /*
654 * Don't let QUEUE_FULLs on the same
655 * jiffies count, they could all be from
656 * same event.
657 */
658 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
659 return 0;
660
661 sdev->last_queue_full_time = jiffies;
662 if (sdev->last_queue_full_depth != depth) {
663 sdev->last_queue_full_count = 1;
664 sdev->last_queue_full_depth = depth;
665 } else {
666 sdev->last_queue_full_count++;
667 }
668
669 if (sdev->last_queue_full_count <= 10)
670 return 0;
671
672 return scsi_change_queue_depth(sdev, depth);
673}
674EXPORT_SYMBOL(scsi_track_queue_full);
675
676/**
677 * scsi_vpd_inquiry - Request a device provide us with a VPD page
678 * @sdev: The device to ask
679 * @buffer: Where to put the result
680 * @page: Which Vital Product Data to return
681 * @len: The length of the buffer
682 *
683 * This is an internal helper function. You probably want to use
684 * scsi_get_vpd_page instead.
685 *
686 * Returns size of the vpd page on success or a negative error number.
687 */
688static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
689 u8 page, unsigned len)
690{
691 int result;
692 unsigned char cmd[16];
693
694 if (len < 4)
695 return -EINVAL;
696
697 cmd[0] = INQUIRY;
698 cmd[1] = 1; /* EVPD */
699 cmd[2] = page;
700 cmd[3] = len >> 8;
701 cmd[4] = len & 0xff;
702 cmd[5] = 0; /* Control byte */
703
704 /*
705 * I'm not convinced we need to try quite this hard to get VPD, but
706 * all the existing users tried this hard.
707 */
708 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
709 len, NULL, 30 * HZ, 3, NULL);
710 if (result)
711 return -EIO;
712
713 /* Sanity check that we got the page back that we asked for */
714 if (buffer[1] != page)
715 return -EIO;
716
717 return get_unaligned_be16(&buffer[2]) + 4;
718}
719
720/**
721 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
722 * @sdev: The device to ask
723 * @page: Which Vital Product Data to return
724 * @buf: where to store the VPD
725 * @buf_len: number of bytes in the VPD buffer area
726 *
727 * SCSI devices may optionally supply Vital Product Data. Each 'page'
728 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
729 * If the device supports this VPD page, this routine returns a pointer
730 * to a buffer containing the data from that page. The caller is
731 * responsible for calling kfree() on this pointer when it is no longer
732 * needed. If we cannot retrieve the VPD page this routine returns %NULL.
733 */
734int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
735 int buf_len)
736{
737 int i, result;
738
739 if (sdev->skip_vpd_pages)
740 goto fail;
741
742 /* Ask for all the pages supported by this device */
743 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len);
744 if (result < 4)
745 goto fail;
746
747 /* If the user actually wanted this page, we can skip the rest */
748 if (page == 0)
749 return 0;
750
751 for (i = 4; i < min(result, buf_len); i++)
752 if (buf[i] == page)
753 goto found;
754
755 if (i < result && i >= buf_len)
756 /* ran off the end of the buffer, give us benefit of doubt */
757 goto found;
758 /* The device claims it doesn't support the requested page */
759 goto fail;
760
761 found:
762 result = scsi_vpd_inquiry(sdev, buf, page, buf_len);
763 if (result < 0)
764 goto fail;
765
766 return 0;
767
768 fail:
769 return -EINVAL;
770}
771EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
772
773/**
774 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure
775 * @sdev: The device to ask
776 *
777 * Attach the 'Device Identification' VPD page (0x83) and the
778 * 'Unit Serial Number' VPD page (0x80) to a SCSI device
779 * structure. This information can be used to identify the device
780 * uniquely.
781 */
782void scsi_attach_vpd(struct scsi_device *sdev)
783{
784 int result, i;
785 int vpd_len = SCSI_VPD_PG_LEN;
786 int pg80_supported = 0;
787 int pg83_supported = 0;
788 unsigned char __rcu *vpd_buf, *orig_vpd_buf = NULL;
789
790 if (!scsi_device_supports_vpd(sdev))
791 return;
792
793retry_pg0:
794 vpd_buf = kmalloc(vpd_len, GFP_KERNEL);
795 if (!vpd_buf)
796 return;
797
798 /* Ask for all the pages supported by this device */
799 result = scsi_vpd_inquiry(sdev, vpd_buf, 0, vpd_len);
800 if (result < 0) {
801 kfree(vpd_buf);
802 return;
803 }
804 if (result > vpd_len) {
805 vpd_len = result;
806 kfree(vpd_buf);
807 goto retry_pg0;
808 }
809
810 for (i = 4; i < result; i++) {
811 if (vpd_buf[i] == 0x80)
812 pg80_supported = 1;
813 if (vpd_buf[i] == 0x83)
814 pg83_supported = 1;
815 }
816 kfree(vpd_buf);
817 vpd_len = SCSI_VPD_PG_LEN;
818
819 if (pg80_supported) {
820retry_pg80:
821 vpd_buf = kmalloc(vpd_len, GFP_KERNEL);
822 if (!vpd_buf)
823 return;
824
825 result = scsi_vpd_inquiry(sdev, vpd_buf, 0x80, vpd_len);
826 if (result < 0) {
827 kfree(vpd_buf);
828 return;
829 }
830 if (result > vpd_len) {
831 vpd_len = result;
832 kfree(vpd_buf);
833 goto retry_pg80;
834 }
835 mutex_lock(&sdev->inquiry_mutex);
836 orig_vpd_buf = sdev->vpd_pg80;
837 sdev->vpd_pg80_len = result;
838 rcu_assign_pointer(sdev->vpd_pg80, vpd_buf);
839 mutex_unlock(&sdev->inquiry_mutex);
840 synchronize_rcu();
841 if (orig_vpd_buf) {
842 kfree(orig_vpd_buf);
843 orig_vpd_buf = NULL;
844 }
845 vpd_len = SCSI_VPD_PG_LEN;
846 }
847
848 if (pg83_supported) {
849retry_pg83:
850 vpd_buf = kmalloc(vpd_len, GFP_KERNEL);
851 if (!vpd_buf)
852 return;
853
854 result = scsi_vpd_inquiry(sdev, vpd_buf, 0x83, vpd_len);
855 if (result < 0) {
856 kfree(vpd_buf);
857 return;
858 }
859 if (result > vpd_len) {
860 vpd_len = result;
861 kfree(vpd_buf);
862 goto retry_pg83;
863 }
864 mutex_lock(&sdev->inquiry_mutex);
865 orig_vpd_buf = sdev->vpd_pg83;
866 sdev->vpd_pg83_len = result;
867 rcu_assign_pointer(sdev->vpd_pg83, vpd_buf);
868 mutex_unlock(&sdev->inquiry_mutex);
869 synchronize_rcu();
870 if (orig_vpd_buf)
871 kfree(orig_vpd_buf);
872 }
873}
874
875/**
876 * scsi_report_opcode - Find out if a given command opcode is supported
877 * @sdev: scsi device to query
878 * @buffer: scratch buffer (must be at least 20 bytes long)
879 * @len: length of buffer
880 * @opcode: opcode for command to look up
881 *
882 * Uses the REPORT SUPPORTED OPERATION CODES to look up the given
883 * opcode. Returns -EINVAL if RSOC fails, 0 if the command opcode is
884 * unsupported and 1 if the device claims to support the command.
885 */
886int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,
887 unsigned int len, unsigned char opcode)
888{
889 unsigned char cmd[16];
890 struct scsi_sense_hdr sshdr;
891 int result;
892
893 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3)
894 return -EINVAL;
895
896 memset(cmd, 0, 16);
897 cmd[0] = MAINTENANCE_IN;
898 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES;
899 cmd[2] = 1; /* One command format */
900 cmd[3] = opcode;
901 put_unaligned_be32(len, &cmd[6]);
902 memset(buffer, 0, len);
903
904 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
905 &sshdr, 30 * HZ, 3, NULL);
906
907 if (result && scsi_sense_valid(&sshdr) &&
908 sshdr.sense_key == ILLEGAL_REQUEST &&
909 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00)
910 return -EINVAL;
911
912 if ((buffer[1] & 3) == 3) /* Command supported */
913 return 1;
914
915 return 0;
916}
917EXPORT_SYMBOL(scsi_report_opcode);
918
919/**
920 * scsi_device_get - get an additional reference to a scsi_device
921 * @sdev: device to get a reference to
922 *
923 * Description: Gets a reference to the scsi_device and increments the use count
924 * of the underlying LLDD module. You must hold host_lock of the
925 * parent Scsi_Host or already have a reference when calling this.
926 *
927 * This will fail if a device is deleted or cancelled, or when the LLD module
928 * is in the process of being unloaded.
929 */
930int scsi_device_get(struct scsi_device *sdev)
931{
932 if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL)
933 goto fail;
934 if (!get_device(&sdev->sdev_gendev))
935 goto fail;
936 if (!try_module_get(sdev->host->hostt->module))
937 goto fail_put_device;
938 return 0;
939
940fail_put_device:
941 put_device(&sdev->sdev_gendev);
942fail:
943 return -ENXIO;
944}
945EXPORT_SYMBOL(scsi_device_get);
946
947/**
948 * scsi_device_put - release a reference to a scsi_device
949 * @sdev: device to release a reference on.
950 *
951 * Description: Release a reference to the scsi_device and decrements the use
952 * count of the underlying LLDD module. The device is freed once the last
953 * user vanishes.
954 */
955void scsi_device_put(struct scsi_device *sdev)
956{
957 module_put(sdev->host->hostt->module);
958 put_device(&sdev->sdev_gendev);
959}
960EXPORT_SYMBOL(scsi_device_put);
961
962/* helper for shost_for_each_device, see that for documentation */
963struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
964 struct scsi_device *prev)
965{
966 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
967 struct scsi_device *next = NULL;
968 unsigned long flags;
969
970 spin_lock_irqsave(shost->host_lock, flags);
971 while (list->next != &shost->__devices) {
972 next = list_entry(list->next, struct scsi_device, siblings);
973 /* skip devices that we can't get a reference to */
974 if (!scsi_device_get(next))
975 break;
976 next = NULL;
977 list = list->next;
978 }
979 spin_unlock_irqrestore(shost->host_lock, flags);
980
981 if (prev)
982 scsi_device_put(prev);
983 return next;
984}
985EXPORT_SYMBOL(__scsi_iterate_devices);
986
987/**
988 * starget_for_each_device - helper to walk all devices of a target
989 * @starget: target whose devices we want to iterate over.
990 * @data: Opaque passed to each function call.
991 * @fn: Function to call on each device
992 *
993 * This traverses over each device of @starget. The devices have
994 * a reference that must be released by scsi_host_put when breaking
995 * out of the loop.
996 */
997void starget_for_each_device(struct scsi_target *starget, void *data,
998 void (*fn)(struct scsi_device *, void *))
999{
1000 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1001 struct scsi_device *sdev;
1002
1003 shost_for_each_device(sdev, shost) {
1004 if ((sdev->channel == starget->channel) &&
1005 (sdev->id == starget->id))
1006 fn(sdev, data);
1007 }
1008}
1009EXPORT_SYMBOL(starget_for_each_device);
1010
1011/**
1012 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
1013 * @starget: target whose devices we want to iterate over.
1014 * @data: parameter for callback @fn()
1015 * @fn: callback function that is invoked for each device
1016 *
1017 * This traverses over each device of @starget. It does _not_
1018 * take a reference on the scsi_device, so the whole loop must be
1019 * protected by shost->host_lock.
1020 *
1021 * Note: The only reason why drivers would want to use this is because
1022 * they need to access the device list in irq context. Otherwise you
1023 * really want to use starget_for_each_device instead.
1024 **/
1025void __starget_for_each_device(struct scsi_target *starget, void *data,
1026 void (*fn)(struct scsi_device *, void *))
1027{
1028 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1029 struct scsi_device *sdev;
1030
1031 __shost_for_each_device(sdev, shost) {
1032 if ((sdev->channel == starget->channel) &&
1033 (sdev->id == starget->id))
1034 fn(sdev, data);
1035 }
1036}
1037EXPORT_SYMBOL(__starget_for_each_device);
1038
1039/**
1040 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
1041 * @starget: SCSI target pointer
1042 * @lun: SCSI Logical Unit Number
1043 *
1044 * Description: Looks up the scsi_device with the specified @lun for a given
1045 * @starget. The returned scsi_device does not have an additional
1046 * reference. You must hold the host's host_lock over this call and
1047 * any access to the returned scsi_device. A scsi_device in state
1048 * SDEV_DEL is skipped.
1049 *
1050 * Note: The only reason why drivers should use this is because
1051 * they need to access the device list in irq context. Otherwise you
1052 * really want to use scsi_device_lookup_by_target instead.
1053 **/
1054struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
1055 u64 lun)
1056{
1057 struct scsi_device *sdev;
1058
1059 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
1060 if (sdev->sdev_state == SDEV_DEL)
1061 continue;
1062 if (sdev->lun ==lun)
1063 return sdev;
1064 }
1065
1066 return NULL;
1067}
1068EXPORT_SYMBOL(__scsi_device_lookup_by_target);
1069
1070/**
1071 * scsi_device_lookup_by_target - find a device given the target
1072 * @starget: SCSI target pointer
1073 * @lun: SCSI Logical Unit Number
1074 *
1075 * Description: Looks up the scsi_device with the specified @lun for a given
1076 * @starget. The returned scsi_device has an additional reference that
1077 * needs to be released with scsi_device_put once you're done with it.
1078 **/
1079struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
1080 u64 lun)
1081{
1082 struct scsi_device *sdev;
1083 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1084 unsigned long flags;
1085
1086 spin_lock_irqsave(shost->host_lock, flags);
1087 sdev = __scsi_device_lookup_by_target(starget, lun);
1088 if (sdev && scsi_device_get(sdev))
1089 sdev = NULL;
1090 spin_unlock_irqrestore(shost->host_lock, flags);
1091
1092 return sdev;
1093}
1094EXPORT_SYMBOL(scsi_device_lookup_by_target);
1095
1096/**
1097 * __scsi_device_lookup - find a device given the host (UNLOCKED)
1098 * @shost: SCSI host pointer
1099 * @channel: SCSI channel (zero if only one channel)
1100 * @id: SCSI target number (physical unit number)
1101 * @lun: SCSI Logical Unit Number
1102 *
1103 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1104 * for a given host. The returned scsi_device does not have an additional
1105 * reference. You must hold the host's host_lock over this call and any access
1106 * to the returned scsi_device.
1107 *
1108 * Note: The only reason why drivers would want to use this is because
1109 * they need to access the device list in irq context. Otherwise you
1110 * really want to use scsi_device_lookup instead.
1111 **/
1112struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
1113 uint channel, uint id, u64 lun)
1114{
1115 struct scsi_device *sdev;
1116
1117 list_for_each_entry(sdev, &shost->__devices, siblings) {
1118 if (sdev->channel == channel && sdev->id == id &&
1119 sdev->lun ==lun)
1120 return sdev;
1121 }
1122
1123 return NULL;
1124}
1125EXPORT_SYMBOL(__scsi_device_lookup);
1126
1127/**
1128 * scsi_device_lookup - find a device given the host
1129 * @shost: SCSI host pointer
1130 * @channel: SCSI channel (zero if only one channel)
1131 * @id: SCSI target number (physical unit number)
1132 * @lun: SCSI Logical Unit Number
1133 *
1134 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1135 * for a given host. The returned scsi_device has an additional reference that
1136 * needs to be released with scsi_device_put once you're done with it.
1137 **/
1138struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1139 uint channel, uint id, u64 lun)
1140{
1141 struct scsi_device *sdev;
1142 unsigned long flags;
1143
1144 spin_lock_irqsave(shost->host_lock, flags);
1145 sdev = __scsi_device_lookup(shost, channel, id, lun);
1146 if (sdev && scsi_device_get(sdev))
1147 sdev = NULL;
1148 spin_unlock_irqrestore(shost->host_lock, flags);
1149
1150 return sdev;
1151}
1152EXPORT_SYMBOL(scsi_device_lookup);
1153
1154MODULE_DESCRIPTION("SCSI core");
1155MODULE_LICENSE("GPL");
1156
1157module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1158MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1159
1160#ifdef CONFIG_SCSI_MQ_DEFAULT
1161bool scsi_use_blk_mq = true;
1162#else
1163bool scsi_use_blk_mq = false;
1164#endif
1165module_param_named(use_blk_mq, scsi_use_blk_mq, bool, S_IWUSR | S_IRUGO);
1166
1167static int __init init_scsi(void)
1168{
1169 int error;
1170
1171 error = scsi_init_queue();
1172 if (error)
1173 return error;
1174 error = scsi_init_procfs();
1175 if (error)
1176 goto cleanup_queue;
1177 error = scsi_init_devinfo();
1178 if (error)
1179 goto cleanup_procfs;
1180 error = scsi_init_hosts();
1181 if (error)
1182 goto cleanup_devlist;
1183 error = scsi_init_sysctl();
1184 if (error)
1185 goto cleanup_hosts;
1186 error = scsi_sysfs_register();
1187 if (error)
1188 goto cleanup_sysctl;
1189
1190 scsi_netlink_init();
1191
1192 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1193 return 0;
1194
1195cleanup_sysctl:
1196 scsi_exit_sysctl();
1197cleanup_hosts:
1198 scsi_exit_hosts();
1199cleanup_devlist:
1200 scsi_exit_devinfo();
1201cleanup_procfs:
1202 scsi_exit_procfs();
1203cleanup_queue:
1204 scsi_exit_queue();
1205 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1206 -error);
1207 return error;
1208}
1209
1210static void __exit exit_scsi(void)
1211{
1212 scsi_netlink_exit();
1213 scsi_sysfs_unregister();
1214 scsi_exit_sysctl();
1215 scsi_exit_hosts();
1216 scsi_exit_devinfo();
1217 scsi_exit_procfs();
1218 scsi_exit_queue();
1219 async_unregister_domain(&scsi_sd_probe_domain);
1220}
1221
1222subsys_initcall(init_scsi);
1223module_exit(exit_scsi);