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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#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);
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
101/**
102 * scsi_put_command - Free a scsi command block
103 * @cmd: command block to free
104 *
105 * Returns: Nothing.
106 *
107 * Notes: The command must not belong to any lists.
108 */
109void scsi_put_command(struct scsi_cmnd *cmd)
110{
111 scsi_del_cmd_from_list(cmd);
112 BUG_ON(delayed_work_pending(&cmd->abort_work));
113}
114
115#ifdef CONFIG_SCSI_LOGGING
116void scsi_log_send(struct scsi_cmnd *cmd)
117{
118 unsigned int level;
119
120 /*
121 * If ML QUEUE log level is greater than or equal to:
122 *
123 * 1: nothing (match completion)
124 *
125 * 2: log opcode + command of all commands + cmd address
126 *
127 * 3: same as 2
128 *
129 * 4: same as 3
130 */
131 if (unlikely(scsi_logging_level)) {
132 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
133 SCSI_LOG_MLQUEUE_BITS);
134 if (level > 1) {
135 scmd_printk(KERN_INFO, cmd,
136 "Send: scmd 0x%p\n", cmd);
137 scsi_print_command(cmd);
138 }
139 }
140}
141
142void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
143{
144 unsigned int level;
145
146 /*
147 * If ML COMPLETE log level is greater than or equal to:
148 *
149 * 1: log disposition, result, opcode + command, and conditionally
150 * sense data for failures or non SUCCESS dispositions.
151 *
152 * 2: same as 1 but for all command completions.
153 *
154 * 3: same as 2
155 *
156 * 4: same as 3 plus dump extra junk
157 */
158 if (unlikely(scsi_logging_level)) {
159 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
160 SCSI_LOG_MLCOMPLETE_BITS);
161 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
162 (level > 1)) {
163 scsi_print_result(cmd, "Done", disposition);
164 scsi_print_command(cmd);
165 if (status_byte(cmd->result) & CHECK_CONDITION)
166 scsi_print_sense(cmd);
167 if (level > 3)
168 scmd_printk(KERN_INFO, cmd,
169 "scsi host busy %d failed %d\n",
170 atomic_read(&cmd->device->host->host_busy),
171 cmd->device->host->host_failed);
172 }
173 }
174}
175#endif
176
177/**
178 * scsi_cmd_get_serial - Assign a serial number to a command
179 * @host: the scsi host
180 * @cmd: command to assign serial number to
181 *
182 * Description: a serial number identifies a request for error recovery
183 * and debugging purposes. Protected by the Host_Lock of host.
184 */
185void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
186{
187 cmd->serial_number = host->cmd_serial_number++;
188 if (cmd->serial_number == 0)
189 cmd->serial_number = host->cmd_serial_number++;
190}
191EXPORT_SYMBOL(scsi_cmd_get_serial);
192
193/**
194 * scsi_finish_command - cleanup and pass command back to upper layer
195 * @cmd: the command
196 *
197 * Description: Pass command off to upper layer for finishing of I/O
198 * request, waking processes that are waiting on results,
199 * etc.
200 */
201void scsi_finish_command(struct scsi_cmnd *cmd)
202{
203 struct scsi_device *sdev = cmd->device;
204 struct scsi_target *starget = scsi_target(sdev);
205 struct Scsi_Host *shost = sdev->host;
206 struct scsi_driver *drv;
207 unsigned int good_bytes;
208
209 scsi_device_unbusy(sdev);
210
211 /*
212 * Clear the flags that say that the device/target/host is no longer
213 * capable of accepting new commands.
214 */
215 if (atomic_read(&shost->host_blocked))
216 atomic_set(&shost->host_blocked, 0);
217 if (atomic_read(&starget->target_blocked))
218 atomic_set(&starget->target_blocked, 0);
219 if (atomic_read(&sdev->device_blocked))
220 atomic_set(&sdev->device_blocked, 0);
221
222 /*
223 * If we have valid sense information, then some kind of recovery
224 * must have taken place. Make a note of this.
225 */
226 if (SCSI_SENSE_VALID(cmd))
227 cmd->result |= (DRIVER_SENSE << 24);
228
229 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
230 "Notifying upper driver of completion "
231 "(result %x)\n", cmd->result));
232
233 good_bytes = scsi_bufflen(cmd);
234 if (!blk_rq_is_passthrough(cmd->request)) {
235 int old_good_bytes = good_bytes;
236 drv = scsi_cmd_to_driver(cmd);
237 if (drv->done)
238 good_bytes = drv->done(cmd);
239 /*
240 * USB may not give sense identifying bad sector and
241 * simply return a residue instead, so subtract off the
242 * residue if drv->done() error processing indicates no
243 * change to the completion length.
244 */
245 if (good_bytes == old_good_bytes)
246 good_bytes -= scsi_get_resid(cmd);
247 }
248 scsi_io_completion(cmd, good_bytes);
249}
250
251/**
252 * scsi_change_queue_depth - change a device's queue depth
253 * @sdev: SCSI Device in question
254 * @depth: number of commands allowed to be queued to the driver
255 *
256 * Sets the device queue depth and returns the new value.
257 */
258int scsi_change_queue_depth(struct scsi_device *sdev, int depth)
259{
260 if (depth > 0) {
261 sdev->queue_depth = depth;
262 wmb();
263 }
264
265 if (sdev->request_queue)
266 blk_set_queue_depth(sdev->request_queue, depth);
267
268 return sdev->queue_depth;
269}
270EXPORT_SYMBOL(scsi_change_queue_depth);
271
272/**
273 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
274 * @sdev: SCSI Device in question
275 * @depth: Current number of outstanding SCSI commands on this device,
276 * not counting the one returned as QUEUE_FULL.
277 *
278 * Description: This function will track successive QUEUE_FULL events on a
279 * specific SCSI device to determine if and when there is a
280 * need to adjust the queue depth on the device.
281 *
282 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
283 * -1 - Drop back to untagged operation using host->cmd_per_lun
284 * as the untagged command depth
285 *
286 * Lock Status: None held on entry
287 *
288 * Notes: Low level drivers may call this at any time and we will do
289 * "The Right Thing." We are interrupt context safe.
290 */
291int scsi_track_queue_full(struct scsi_device *sdev, int depth)
292{
293
294 /*
295 * Don't let QUEUE_FULLs on the same
296 * jiffies count, they could all be from
297 * same event.
298 */
299 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
300 return 0;
301
302 sdev->last_queue_full_time = jiffies;
303 if (sdev->last_queue_full_depth != depth) {
304 sdev->last_queue_full_count = 1;
305 sdev->last_queue_full_depth = depth;
306 } else {
307 sdev->last_queue_full_count++;
308 }
309
310 if (sdev->last_queue_full_count <= 10)
311 return 0;
312
313 return scsi_change_queue_depth(sdev, depth);
314}
315EXPORT_SYMBOL(scsi_track_queue_full);
316
317/**
318 * scsi_vpd_inquiry - Request a device provide us with a VPD page
319 * @sdev: The device to ask
320 * @buffer: Where to put the result
321 * @page: Which Vital Product Data to return
322 * @len: The length of the buffer
323 *
324 * This is an internal helper function. You probably want to use
325 * scsi_get_vpd_page instead.
326 *
327 * Returns size of the vpd page on success or a negative error number.
328 */
329static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
330 u8 page, unsigned len)
331{
332 int result;
333 unsigned char cmd[16];
334
335 if (len < 4)
336 return -EINVAL;
337
338 cmd[0] = INQUIRY;
339 cmd[1] = 1; /* EVPD */
340 cmd[2] = page;
341 cmd[3] = len >> 8;
342 cmd[4] = len & 0xff;
343 cmd[5] = 0; /* Control byte */
344
345 /*
346 * I'm not convinced we need to try quite this hard to get VPD, but
347 * all the existing users tried this hard.
348 */
349 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
350 len, NULL, 30 * HZ, 3, NULL);
351 if (result)
352 return -EIO;
353
354 /* Sanity check that we got the page back that we asked for */
355 if (buffer[1] != page)
356 return -EIO;
357
358 return get_unaligned_be16(&buffer[2]) + 4;
359}
360
361/**
362 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
363 * @sdev: The device to ask
364 * @page: Which Vital Product Data to return
365 * @buf: where to store the VPD
366 * @buf_len: number of bytes in the VPD buffer area
367 *
368 * SCSI devices may optionally supply Vital Product Data. Each 'page'
369 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
370 * If the device supports this VPD page, this routine returns a pointer
371 * to a buffer containing the data from that page. The caller is
372 * responsible for calling kfree() on this pointer when it is no longer
373 * needed. If we cannot retrieve the VPD page this routine returns %NULL.
374 */
375int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
376 int buf_len)
377{
378 int i, result;
379
380 if (sdev->skip_vpd_pages)
381 goto fail;
382
383 /* Ask for all the pages supported by this device */
384 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len);
385 if (result < 4)
386 goto fail;
387
388 /* If the user actually wanted this page, we can skip the rest */
389 if (page == 0)
390 return 0;
391
392 for (i = 4; i < min(result, buf_len); i++)
393 if (buf[i] == page)
394 goto found;
395
396 if (i < result && i >= buf_len)
397 /* ran off the end of the buffer, give us benefit of doubt */
398 goto found;
399 /* The device claims it doesn't support the requested page */
400 goto fail;
401
402 found:
403 result = scsi_vpd_inquiry(sdev, buf, page, buf_len);
404 if (result < 0)
405 goto fail;
406
407 return 0;
408
409 fail:
410 return -EINVAL;
411}
412EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
413
414/**
415 * scsi_get_vpd_buf - Get Vital Product Data from a SCSI device
416 * @sdev: The device to ask
417 * @page: Which Vital Product Data to return
418 *
419 * Returns %NULL upon failure.
420 */
421static struct scsi_vpd *scsi_get_vpd_buf(struct scsi_device *sdev, u8 page)
422{
423 struct scsi_vpd *vpd_buf;
424 int vpd_len = SCSI_VPD_PG_LEN, result;
425
426retry_pg:
427 vpd_buf = kmalloc(sizeof(*vpd_buf) + vpd_len, GFP_KERNEL);
428 if (!vpd_buf)
429 return NULL;
430
431 result = scsi_vpd_inquiry(sdev, vpd_buf->data, page, vpd_len);
432 if (result < 0) {
433 kfree(vpd_buf);
434 return NULL;
435 }
436 if (result > vpd_len) {
437 vpd_len = result;
438 kfree(vpd_buf);
439 goto retry_pg;
440 }
441
442 vpd_buf->len = result;
443
444 return vpd_buf;
445}
446
447static void scsi_update_vpd_page(struct scsi_device *sdev, u8 page,
448 struct scsi_vpd __rcu **sdev_vpd_buf)
449{
450 struct scsi_vpd *vpd_buf;
451
452 vpd_buf = scsi_get_vpd_buf(sdev, page);
453 if (!vpd_buf)
454 return;
455
456 mutex_lock(&sdev->inquiry_mutex);
457 rcu_swap_protected(*sdev_vpd_buf, vpd_buf,
458 lockdep_is_held(&sdev->inquiry_mutex));
459 mutex_unlock(&sdev->inquiry_mutex);
460
461 if (vpd_buf)
462 kfree_rcu(vpd_buf, rcu);
463}
464
465/**
466 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure
467 * @sdev: The device to ask
468 *
469 * Attach the 'Device Identification' VPD page (0x83) and the
470 * 'Unit Serial Number' VPD page (0x80) to a SCSI device
471 * structure. This information can be used to identify the device
472 * uniquely.
473 */
474void scsi_attach_vpd(struct scsi_device *sdev)
475{
476 int i;
477 struct scsi_vpd *vpd_buf;
478
479 if (!scsi_device_supports_vpd(sdev))
480 return;
481
482 /* Ask for all the pages supported by this device */
483 vpd_buf = scsi_get_vpd_buf(sdev, 0);
484 if (!vpd_buf)
485 return;
486
487 for (i = 4; i < vpd_buf->len; i++) {
488 if (vpd_buf->data[i] == 0x80)
489 scsi_update_vpd_page(sdev, 0x80, &sdev->vpd_pg80);
490 if (vpd_buf->data[i] == 0x83)
491 scsi_update_vpd_page(sdev, 0x83, &sdev->vpd_pg83);
492 }
493 kfree(vpd_buf);
494}
495
496/**
497 * scsi_report_opcode - Find out if a given command opcode is supported
498 * @sdev: scsi device to query
499 * @buffer: scratch buffer (must be at least 20 bytes long)
500 * @len: length of buffer
501 * @opcode: opcode for command to look up
502 *
503 * Uses the REPORT SUPPORTED OPERATION CODES to look up the given
504 * opcode. Returns -EINVAL if RSOC fails, 0 if the command opcode is
505 * unsupported and 1 if the device claims to support the command.
506 */
507int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,
508 unsigned int len, unsigned char opcode)
509{
510 unsigned char cmd[16];
511 struct scsi_sense_hdr sshdr;
512 int result;
513
514 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3)
515 return -EINVAL;
516
517 memset(cmd, 0, 16);
518 cmd[0] = MAINTENANCE_IN;
519 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES;
520 cmd[2] = 1; /* One command format */
521 cmd[3] = opcode;
522 put_unaligned_be32(len, &cmd[6]);
523 memset(buffer, 0, len);
524
525 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
526 &sshdr, 30 * HZ, 3, NULL);
527
528 if (result && scsi_sense_valid(&sshdr) &&
529 sshdr.sense_key == ILLEGAL_REQUEST &&
530 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00)
531 return -EINVAL;
532
533 if ((buffer[1] & 3) == 3) /* Command supported */
534 return 1;
535
536 return 0;
537}
538EXPORT_SYMBOL(scsi_report_opcode);
539
540/**
541 * scsi_device_get - get an additional reference to a scsi_device
542 * @sdev: device to get a reference to
543 *
544 * Description: Gets a reference to the scsi_device and increments the use count
545 * of the underlying LLDD module. You must hold host_lock of the
546 * parent Scsi_Host or already have a reference when calling this.
547 *
548 * This will fail if a device is deleted or cancelled, or when the LLD module
549 * is in the process of being unloaded.
550 */
551int scsi_device_get(struct scsi_device *sdev)
552{
553 if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL)
554 goto fail;
555 if (!get_device(&sdev->sdev_gendev))
556 goto fail;
557 if (!try_module_get(sdev->host->hostt->module))
558 goto fail_put_device;
559 return 0;
560
561fail_put_device:
562 put_device(&sdev->sdev_gendev);
563fail:
564 return -ENXIO;
565}
566EXPORT_SYMBOL(scsi_device_get);
567
568/**
569 * scsi_device_put - release a reference to a scsi_device
570 * @sdev: device to release a reference on.
571 *
572 * Description: Release a reference to the scsi_device and decrements the use
573 * count of the underlying LLDD module. The device is freed once the last
574 * user vanishes.
575 */
576void scsi_device_put(struct scsi_device *sdev)
577{
578 module_put(sdev->host->hostt->module);
579 put_device(&sdev->sdev_gendev);
580}
581EXPORT_SYMBOL(scsi_device_put);
582
583/* helper for shost_for_each_device, see that for documentation */
584struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
585 struct scsi_device *prev)
586{
587 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
588 struct scsi_device *next = NULL;
589 unsigned long flags;
590
591 spin_lock_irqsave(shost->host_lock, flags);
592 while (list->next != &shost->__devices) {
593 next = list_entry(list->next, struct scsi_device, siblings);
594 /* skip devices that we can't get a reference to */
595 if (!scsi_device_get(next))
596 break;
597 next = NULL;
598 list = list->next;
599 }
600 spin_unlock_irqrestore(shost->host_lock, flags);
601
602 if (prev)
603 scsi_device_put(prev);
604 return next;
605}
606EXPORT_SYMBOL(__scsi_iterate_devices);
607
608/**
609 * starget_for_each_device - helper to walk all devices of a target
610 * @starget: target whose devices we want to iterate over.
611 * @data: Opaque passed to each function call.
612 * @fn: Function to call on each device
613 *
614 * This traverses over each device of @starget. The devices have
615 * a reference that must be released by scsi_host_put when breaking
616 * out of the loop.
617 */
618void starget_for_each_device(struct scsi_target *starget, void *data,
619 void (*fn)(struct scsi_device *, void *))
620{
621 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
622 struct scsi_device *sdev;
623
624 shost_for_each_device(sdev, shost) {
625 if ((sdev->channel == starget->channel) &&
626 (sdev->id == starget->id))
627 fn(sdev, data);
628 }
629}
630EXPORT_SYMBOL(starget_for_each_device);
631
632/**
633 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
634 * @starget: target whose devices we want to iterate over.
635 * @data: parameter for callback @fn()
636 * @fn: callback function that is invoked for each device
637 *
638 * This traverses over each device of @starget. It does _not_
639 * take a reference on the scsi_device, so the whole loop must be
640 * protected by shost->host_lock.
641 *
642 * Note: The only reason why drivers would want to use this is because
643 * they need to access the device list in irq context. Otherwise you
644 * really want to use starget_for_each_device instead.
645 **/
646void __starget_for_each_device(struct scsi_target *starget, void *data,
647 void (*fn)(struct scsi_device *, void *))
648{
649 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
650 struct scsi_device *sdev;
651
652 __shost_for_each_device(sdev, shost) {
653 if ((sdev->channel == starget->channel) &&
654 (sdev->id == starget->id))
655 fn(sdev, data);
656 }
657}
658EXPORT_SYMBOL(__starget_for_each_device);
659
660/**
661 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
662 * @starget: SCSI target pointer
663 * @lun: SCSI Logical Unit Number
664 *
665 * Description: Looks up the scsi_device with the specified @lun for a given
666 * @starget. The returned scsi_device does not have an additional
667 * reference. You must hold the host's host_lock over this call and
668 * any access to the returned scsi_device. A scsi_device in state
669 * SDEV_DEL is skipped.
670 *
671 * Note: The only reason why drivers should use this is because
672 * they need to access the device list in irq context. Otherwise you
673 * really want to use scsi_device_lookup_by_target instead.
674 **/
675struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
676 u64 lun)
677{
678 struct scsi_device *sdev;
679
680 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
681 if (sdev->sdev_state == SDEV_DEL)
682 continue;
683 if (sdev->lun ==lun)
684 return sdev;
685 }
686
687 return NULL;
688}
689EXPORT_SYMBOL(__scsi_device_lookup_by_target);
690
691/**
692 * scsi_device_lookup_by_target - find a device given the target
693 * @starget: SCSI target pointer
694 * @lun: SCSI Logical Unit Number
695 *
696 * Description: Looks up the scsi_device with the specified @lun for a given
697 * @starget. The returned scsi_device has an additional reference that
698 * needs to be released with scsi_device_put once you're done with it.
699 **/
700struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
701 u64 lun)
702{
703 struct scsi_device *sdev;
704 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
705 unsigned long flags;
706
707 spin_lock_irqsave(shost->host_lock, flags);
708 sdev = __scsi_device_lookup_by_target(starget, lun);
709 if (sdev && scsi_device_get(sdev))
710 sdev = NULL;
711 spin_unlock_irqrestore(shost->host_lock, flags);
712
713 return sdev;
714}
715EXPORT_SYMBOL(scsi_device_lookup_by_target);
716
717/**
718 * __scsi_device_lookup - find a device given the host (UNLOCKED)
719 * @shost: SCSI host pointer
720 * @channel: SCSI channel (zero if only one channel)
721 * @id: SCSI target number (physical unit number)
722 * @lun: SCSI Logical Unit Number
723 *
724 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
725 * for a given host. The returned scsi_device does not have an additional
726 * reference. You must hold the host's host_lock over this call and any access
727 * to the returned scsi_device.
728 *
729 * Note: The only reason why drivers would want to use this is because
730 * they need to access the device list in irq context. Otherwise you
731 * really want to use scsi_device_lookup instead.
732 **/
733struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
734 uint channel, uint id, u64 lun)
735{
736 struct scsi_device *sdev;
737
738 list_for_each_entry(sdev, &shost->__devices, siblings) {
739 if (sdev->sdev_state == SDEV_DEL)
740 continue;
741 if (sdev->channel == channel && sdev->id == id &&
742 sdev->lun ==lun)
743 return sdev;
744 }
745
746 return NULL;
747}
748EXPORT_SYMBOL(__scsi_device_lookup);
749
750/**
751 * scsi_device_lookup - find a device given the host
752 * @shost: SCSI host pointer
753 * @channel: SCSI channel (zero if only one channel)
754 * @id: SCSI target number (physical unit number)
755 * @lun: SCSI Logical Unit Number
756 *
757 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
758 * for a given host. The returned scsi_device has an additional reference that
759 * needs to be released with scsi_device_put once you're done with it.
760 **/
761struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
762 uint channel, uint id, u64 lun)
763{
764 struct scsi_device *sdev;
765 unsigned long flags;
766
767 spin_lock_irqsave(shost->host_lock, flags);
768 sdev = __scsi_device_lookup(shost, channel, id, lun);
769 if (sdev && scsi_device_get(sdev))
770 sdev = NULL;
771 spin_unlock_irqrestore(shost->host_lock, flags);
772
773 return sdev;
774}
775EXPORT_SYMBOL(scsi_device_lookup);
776
777MODULE_DESCRIPTION("SCSI core");
778MODULE_LICENSE("GPL");
779
780module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
781MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
782
783#ifdef CONFIG_SCSI_MQ_DEFAULT
784bool scsi_use_blk_mq = true;
785#else
786bool scsi_use_blk_mq = false;
787#endif
788module_param_named(use_blk_mq, scsi_use_blk_mq, bool, S_IWUSR | S_IRUGO);
789
790static int __init init_scsi(void)
791{
792 int error;
793
794 error = scsi_init_queue();
795 if (error)
796 return error;
797 error = scsi_init_procfs();
798 if (error)
799 goto cleanup_queue;
800 error = scsi_init_devinfo();
801 if (error)
802 goto cleanup_procfs;
803 error = scsi_init_hosts();
804 if (error)
805 goto cleanup_devlist;
806 error = scsi_init_sysctl();
807 if (error)
808 goto cleanup_hosts;
809 error = scsi_sysfs_register();
810 if (error)
811 goto cleanup_sysctl;
812
813 scsi_netlink_init();
814
815 printk(KERN_NOTICE "SCSI subsystem initialized\n");
816 return 0;
817
818cleanup_sysctl:
819 scsi_exit_sysctl();
820cleanup_hosts:
821 scsi_exit_hosts();
822cleanup_devlist:
823 scsi_exit_devinfo();
824cleanup_procfs:
825 scsi_exit_procfs();
826cleanup_queue:
827 scsi_exit_queue();
828 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
829 -error);
830 return error;
831}
832
833static void __exit exit_scsi(void)
834{
835 scsi_netlink_exit();
836 scsi_sysfs_unregister();
837 scsi_exit_sysctl();
838 scsi_exit_hosts();
839 scsi_exit_devinfo();
840 scsi_exit_procfs();
841 scsi_exit_queue();
842 async_unregister_domain(&scsi_sd_probe_domain);
843}
844
845subsys_initcall(init_scsi);
846module_exit(exit_scsi);