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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// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * scsi.c Copyright (C) 1992 Drew Eckhardt
4 * Copyright (C) 1993, 1994, 1995, 1999 Eric Youngdale
5 * Copyright (C) 2002, 2003 Christoph Hellwig
6 *
7 * generic mid-level SCSI driver
8 * Initial versions: Drew Eckhardt
9 * Subsequent revisions: Eric Youngdale
10 *
11 * <drew@colorado.edu>
12 *
13 * Bug correction thanks go to :
14 * Rik Faith <faith@cs.unc.edu>
15 * Tommy Thorn <tthorn>
16 * Thomas Wuensche <tw@fgb1.fgb.mw.tu-muenchen.de>
17 *
18 * Modified by Eric Youngdale eric@andante.org or ericy@gnu.ai.mit.edu to
19 * add scatter-gather, multiple outstanding request, and other
20 * enhancements.
21 *
22 * Native multichannel, wide scsi, /proc/scsi and hot plugging
23 * support added by Michael Neuffer <mike@i-connect.net>
24 *
25 * Added request_module("scsi_hostadapter") for kerneld:
26 * (Put an "alias scsi_hostadapter your_hostadapter" in /etc/modprobe.conf)
27 * Bjorn Ekwall <bj0rn@blox.se>
28 * (changed to kmod)
29 *
30 * Major improvements to the timeout, abort, and reset processing,
31 * as well as performance modifications for large queue depths by
32 * Leonard N. Zubkoff <lnz@dandelion.com>
33 *
34 * Converted cli() code to spinlocks, Ingo Molnar
35 *
36 * Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
37 *
38 * out_of_space hacks, D. Gilbert (dpg) 990608
39 */
40
41#include <linux/module.h>
42#include <linux/moduleparam.h>
43#include <linux/kernel.h>
44#include <linux/timer.h>
45#include <linux/string.h>
46#include <linux/slab.h>
47#include <linux/blkdev.h>
48#include <linux/delay.h>
49#include <linux/init.h>
50#include <linux/completion.h>
51#include <linux/unistd.h>
52#include <linux/spinlock.h>
53#include <linux/kmod.h>
54#include <linux/interrupt.h>
55#include <linux/notifier.h>
56#include <linux/cpu.h>
57#include <linux/mutex.h>
58#include <linux/async.h>
59#include <asm/unaligned.h>
60
61#include <scsi/scsi.h>
62#include <scsi/scsi_cmnd.h>
63#include <scsi/scsi_dbg.h>
64#include <scsi/scsi_device.h>
65#include <scsi/scsi_driver.h>
66#include <scsi/scsi_eh.h>
67#include <scsi/scsi_host.h>
68#include <scsi/scsi_tcq.h>
69
70#include "scsi_priv.h"
71#include "scsi_logging.h"
72
73#define CREATE_TRACE_POINTS
74#include <trace/events/scsi.h>
75
76/*
77 * Definitions and constants.
78 */
79
80/*
81 * Note - the initial logging level can be set here to log events at boot time.
82 * After the system is up, you may enable logging via the /proc interface.
83 */
84unsigned int scsi_logging_level;
85#if defined(CONFIG_SCSI_LOGGING)
86EXPORT_SYMBOL(scsi_logging_level);
87#endif
88
89/*
90 * Domain for asynchronous system resume operations. It is marked 'exclusive'
91 * to avoid being included in the async_synchronize_full() that is invoked by
92 * dpm_resume().
93 */
94ASYNC_DOMAIN_EXCLUSIVE(scsi_sd_pm_domain);
95EXPORT_SYMBOL(scsi_sd_pm_domain);
96
97#ifdef CONFIG_SCSI_LOGGING
98void scsi_log_send(struct scsi_cmnd *cmd)
99{
100 unsigned int level;
101
102 /*
103 * If ML QUEUE log level is greater than or equal to:
104 *
105 * 1: nothing (match completion)
106 *
107 * 2: log opcode + command of all commands + cmd address
108 *
109 * 3: same as 2
110 *
111 * 4: same as 3
112 */
113 if (unlikely(scsi_logging_level)) {
114 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
115 SCSI_LOG_MLQUEUE_BITS);
116 if (level > 1) {
117 scmd_printk(KERN_INFO, cmd,
118 "Send: scmd 0x%p\n", cmd);
119 scsi_print_command(cmd);
120 }
121 }
122}
123
124void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
125{
126 unsigned int level;
127
128 /*
129 * If ML COMPLETE log level is greater than or equal to:
130 *
131 * 1: log disposition, result, opcode + command, and conditionally
132 * sense data for failures or non SUCCESS dispositions.
133 *
134 * 2: same as 1 but for all command completions.
135 *
136 * 3: same as 2
137 *
138 * 4: same as 3 plus dump extra junk
139 */
140 if (unlikely(scsi_logging_level)) {
141 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
142 SCSI_LOG_MLCOMPLETE_BITS);
143 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
144 (level > 1)) {
145 scsi_print_result(cmd, "Done", disposition);
146 scsi_print_command(cmd);
147 if (scsi_status_is_check_condition(cmd->result))
148 scsi_print_sense(cmd);
149 if (level > 3)
150 scmd_printk(KERN_INFO, cmd,
151 "scsi host busy %d failed %d\n",
152 scsi_host_busy(cmd->device->host),
153 cmd->device->host->host_failed);
154 }
155 }
156}
157#endif
158
159/**
160 * scsi_finish_command - cleanup and pass command back to upper layer
161 * @cmd: the command
162 *
163 * Description: Pass command off to upper layer for finishing of I/O
164 * request, waking processes that are waiting on results,
165 * etc.
166 */
167void scsi_finish_command(struct scsi_cmnd *cmd)
168{
169 struct scsi_device *sdev = cmd->device;
170 struct scsi_target *starget = scsi_target(sdev);
171 struct Scsi_Host *shost = sdev->host;
172 struct scsi_driver *drv;
173 unsigned int good_bytes;
174
175 scsi_device_unbusy(sdev, cmd);
176
177 /*
178 * Clear the flags that say that the device/target/host is no longer
179 * capable of accepting new commands.
180 */
181 if (atomic_read(&shost->host_blocked))
182 atomic_set(&shost->host_blocked, 0);
183 if (atomic_read(&starget->target_blocked))
184 atomic_set(&starget->target_blocked, 0);
185 if (atomic_read(&sdev->device_blocked))
186 atomic_set(&sdev->device_blocked, 0);
187
188 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
189 "Notifying upper driver of completion "
190 "(result %x)\n", cmd->result));
191
192 good_bytes = scsi_bufflen(cmd);
193 if (!blk_rq_is_passthrough(cmd->request)) {
194 int old_good_bytes = good_bytes;
195 drv = scsi_cmd_to_driver(cmd);
196 if (drv->done)
197 good_bytes = drv->done(cmd);
198 /*
199 * USB may not give sense identifying bad sector and
200 * simply return a residue instead, so subtract off the
201 * residue if drv->done() error processing indicates no
202 * change to the completion length.
203 */
204 if (good_bytes == old_good_bytes)
205 good_bytes -= scsi_get_resid(cmd);
206 }
207 scsi_io_completion(cmd, good_bytes);
208}
209
210
211/*
212 * 1024 is big enough for saturating the fast scsi LUN now
213 */
214int scsi_device_max_queue_depth(struct scsi_device *sdev)
215{
216 return max_t(int, sdev->host->can_queue, 1024);
217}
218
219/**
220 * scsi_change_queue_depth - change a device's queue depth
221 * @sdev: SCSI Device in question
222 * @depth: number of commands allowed to be queued to the driver
223 *
224 * Sets the device queue depth and returns the new value.
225 */
226int scsi_change_queue_depth(struct scsi_device *sdev, int depth)
227{
228 depth = min_t(int, depth, scsi_device_max_queue_depth(sdev));
229
230 if (depth > 0) {
231 sdev->queue_depth = depth;
232 wmb();
233 }
234
235 if (sdev->request_queue)
236 blk_set_queue_depth(sdev->request_queue, depth);
237
238 sbitmap_resize(&sdev->budget_map, sdev->queue_depth);
239
240 return sdev->queue_depth;
241}
242EXPORT_SYMBOL(scsi_change_queue_depth);
243
244/**
245 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
246 * @sdev: SCSI Device in question
247 * @depth: Current number of outstanding SCSI commands on this device,
248 * not counting the one returned as QUEUE_FULL.
249 *
250 * Description: This function will track successive QUEUE_FULL events on a
251 * specific SCSI device to determine if and when there is a
252 * need to adjust the queue depth on the device.
253 *
254 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
255 * -1 - Drop back to untagged operation using host->cmd_per_lun
256 * as the untagged command depth
257 *
258 * Lock Status: None held on entry
259 *
260 * Notes: Low level drivers may call this at any time and we will do
261 * "The Right Thing." We are interrupt context safe.
262 */
263int scsi_track_queue_full(struct scsi_device *sdev, int depth)
264{
265
266 /*
267 * Don't let QUEUE_FULLs on the same
268 * jiffies count, they could all be from
269 * same event.
270 */
271 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
272 return 0;
273
274 sdev->last_queue_full_time = jiffies;
275 if (sdev->last_queue_full_depth != depth) {
276 sdev->last_queue_full_count = 1;
277 sdev->last_queue_full_depth = depth;
278 } else {
279 sdev->last_queue_full_count++;
280 }
281
282 if (sdev->last_queue_full_count <= 10)
283 return 0;
284
285 return scsi_change_queue_depth(sdev, depth);
286}
287EXPORT_SYMBOL(scsi_track_queue_full);
288
289/**
290 * scsi_vpd_inquiry - Request a device provide us with a VPD page
291 * @sdev: The device to ask
292 * @buffer: Where to put the result
293 * @page: Which Vital Product Data to return
294 * @len: The length of the buffer
295 *
296 * This is an internal helper function. You probably want to use
297 * scsi_get_vpd_page instead.
298 *
299 * Returns size of the vpd page on success or a negative error number.
300 */
301static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
302 u8 page, unsigned len)
303{
304 int result;
305 unsigned char cmd[16];
306
307 if (len < 4)
308 return -EINVAL;
309
310 cmd[0] = INQUIRY;
311 cmd[1] = 1; /* EVPD */
312 cmd[2] = page;
313 cmd[3] = len >> 8;
314 cmd[4] = len & 0xff;
315 cmd[5] = 0; /* Control byte */
316
317 /*
318 * I'm not convinced we need to try quite this hard to get VPD, but
319 * all the existing users tried this hard.
320 */
321 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
322 len, NULL, 30 * HZ, 3, NULL);
323 if (result)
324 return -EIO;
325
326 /* Sanity check that we got the page back that we asked for */
327 if (buffer[1] != page)
328 return -EIO;
329
330 return get_unaligned_be16(&buffer[2]) + 4;
331}
332
333/**
334 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
335 * @sdev: The device to ask
336 * @page: Which Vital Product Data to return
337 * @buf: where to store the VPD
338 * @buf_len: number of bytes in the VPD buffer area
339 *
340 * SCSI devices may optionally supply Vital Product Data. Each 'page'
341 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
342 * If the device supports this VPD page, this routine returns a pointer
343 * to a buffer containing the data from that page. The caller is
344 * responsible for calling kfree() on this pointer when it is no longer
345 * needed. If we cannot retrieve the VPD page this routine returns %NULL.
346 */
347int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
348 int buf_len)
349{
350 int i, result;
351
352 if (sdev->skip_vpd_pages)
353 goto fail;
354
355 /* Ask for all the pages supported by this device */
356 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len);
357 if (result < 4)
358 goto fail;
359
360 /* If the user actually wanted this page, we can skip the rest */
361 if (page == 0)
362 return 0;
363
364 for (i = 4; i < min(result, buf_len); i++)
365 if (buf[i] == page)
366 goto found;
367
368 if (i < result && i >= buf_len)
369 /* ran off the end of the buffer, give us benefit of doubt */
370 goto found;
371 /* The device claims it doesn't support the requested page */
372 goto fail;
373
374 found:
375 result = scsi_vpd_inquiry(sdev, buf, page, buf_len);
376 if (result < 0)
377 goto fail;
378
379 return 0;
380
381 fail:
382 return -EINVAL;
383}
384EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
385
386/**
387 * scsi_get_vpd_buf - Get Vital Product Data from a SCSI device
388 * @sdev: The device to ask
389 * @page: Which Vital Product Data to return
390 *
391 * Returns %NULL upon failure.
392 */
393static struct scsi_vpd *scsi_get_vpd_buf(struct scsi_device *sdev, u8 page)
394{
395 struct scsi_vpd *vpd_buf;
396 int vpd_len = SCSI_VPD_PG_LEN, result;
397
398retry_pg:
399 vpd_buf = kmalloc(sizeof(*vpd_buf) + vpd_len, GFP_KERNEL);
400 if (!vpd_buf)
401 return NULL;
402
403 result = scsi_vpd_inquiry(sdev, vpd_buf->data, page, vpd_len);
404 if (result < 0) {
405 kfree(vpd_buf);
406 return NULL;
407 }
408 if (result > vpd_len) {
409 vpd_len = result;
410 kfree(vpd_buf);
411 goto retry_pg;
412 }
413
414 vpd_buf->len = result;
415
416 return vpd_buf;
417}
418
419static void scsi_update_vpd_page(struct scsi_device *sdev, u8 page,
420 struct scsi_vpd __rcu **sdev_vpd_buf)
421{
422 struct scsi_vpd *vpd_buf;
423
424 vpd_buf = scsi_get_vpd_buf(sdev, page);
425 if (!vpd_buf)
426 return;
427
428 mutex_lock(&sdev->inquiry_mutex);
429 vpd_buf = rcu_replace_pointer(*sdev_vpd_buf, vpd_buf,
430 lockdep_is_held(&sdev->inquiry_mutex));
431 mutex_unlock(&sdev->inquiry_mutex);
432
433 if (vpd_buf)
434 kfree_rcu(vpd_buf, rcu);
435}
436
437/**
438 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure
439 * @sdev: The device to ask
440 *
441 * Attach the 'Device Identification' VPD page (0x83) and the
442 * 'Unit Serial Number' VPD page (0x80) to a SCSI device
443 * structure. This information can be used to identify the device
444 * uniquely.
445 */
446void scsi_attach_vpd(struct scsi_device *sdev)
447{
448 int i;
449 struct scsi_vpd *vpd_buf;
450
451 if (!scsi_device_supports_vpd(sdev))
452 return;
453
454 /* Ask for all the pages supported by this device */
455 vpd_buf = scsi_get_vpd_buf(sdev, 0);
456 if (!vpd_buf)
457 return;
458
459 for (i = 4; i < vpd_buf->len; i++) {
460 if (vpd_buf->data[i] == 0x0)
461 scsi_update_vpd_page(sdev, 0x0, &sdev->vpd_pg0);
462 if (vpd_buf->data[i] == 0x80)
463 scsi_update_vpd_page(sdev, 0x80, &sdev->vpd_pg80);
464 if (vpd_buf->data[i] == 0x83)
465 scsi_update_vpd_page(sdev, 0x83, &sdev->vpd_pg83);
466 if (vpd_buf->data[i] == 0x89)
467 scsi_update_vpd_page(sdev, 0x89, &sdev->vpd_pg89);
468 }
469 kfree(vpd_buf);
470}
471
472/**
473 * scsi_report_opcode - Find out if a given command opcode is supported
474 * @sdev: scsi device to query
475 * @buffer: scratch buffer (must be at least 20 bytes long)
476 * @len: length of buffer
477 * @opcode: opcode for command to look up
478 *
479 * Uses the REPORT SUPPORTED OPERATION CODES to look up the given
480 * opcode. Returns -EINVAL if RSOC fails, 0 if the command opcode is
481 * unsupported and 1 if the device claims to support the command.
482 */
483int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,
484 unsigned int len, unsigned char opcode)
485{
486 unsigned char cmd[16];
487 struct scsi_sense_hdr sshdr;
488 int result;
489
490 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3)
491 return -EINVAL;
492
493 memset(cmd, 0, 16);
494 cmd[0] = MAINTENANCE_IN;
495 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES;
496 cmd[2] = 1; /* One command format */
497 cmd[3] = opcode;
498 put_unaligned_be32(len, &cmd[6]);
499 memset(buffer, 0, len);
500
501 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
502 &sshdr, 30 * HZ, 3, NULL);
503
504 if (result < 0)
505 return result;
506 if (result && scsi_sense_valid(&sshdr) &&
507 sshdr.sense_key == ILLEGAL_REQUEST &&
508 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00)
509 return -EINVAL;
510
511 if ((buffer[1] & 3) == 3) /* Command supported */
512 return 1;
513
514 return 0;
515}
516EXPORT_SYMBOL(scsi_report_opcode);
517
518/**
519 * scsi_device_get - get an additional reference to a scsi_device
520 * @sdev: device to get a reference to
521 *
522 * Description: Gets a reference to the scsi_device and increments the use count
523 * of the underlying LLDD module. You must hold host_lock of the
524 * parent Scsi_Host or already have a reference when calling this.
525 *
526 * This will fail if a device is deleted or cancelled, or when the LLD module
527 * is in the process of being unloaded.
528 */
529int scsi_device_get(struct scsi_device *sdev)
530{
531 if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL)
532 goto fail;
533 if (!get_device(&sdev->sdev_gendev))
534 goto fail;
535 if (!try_module_get(sdev->host->hostt->module))
536 goto fail_put_device;
537 return 0;
538
539fail_put_device:
540 put_device(&sdev->sdev_gendev);
541fail:
542 return -ENXIO;
543}
544EXPORT_SYMBOL(scsi_device_get);
545
546/**
547 * scsi_device_put - release a reference to a scsi_device
548 * @sdev: device to release a reference on.
549 *
550 * Description: Release a reference to the scsi_device and decrements the use
551 * count of the underlying LLDD module. The device is freed once the last
552 * user vanishes.
553 */
554void scsi_device_put(struct scsi_device *sdev)
555{
556 module_put(sdev->host->hostt->module);
557 put_device(&sdev->sdev_gendev);
558}
559EXPORT_SYMBOL(scsi_device_put);
560
561/* helper for shost_for_each_device, see that for documentation */
562struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
563 struct scsi_device *prev)
564{
565 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
566 struct scsi_device *next = NULL;
567 unsigned long flags;
568
569 spin_lock_irqsave(shost->host_lock, flags);
570 while (list->next != &shost->__devices) {
571 next = list_entry(list->next, struct scsi_device, siblings);
572 /* skip devices that we can't get a reference to */
573 if (!scsi_device_get(next))
574 break;
575 next = NULL;
576 list = list->next;
577 }
578 spin_unlock_irqrestore(shost->host_lock, flags);
579
580 if (prev)
581 scsi_device_put(prev);
582 return next;
583}
584EXPORT_SYMBOL(__scsi_iterate_devices);
585
586/**
587 * starget_for_each_device - helper to walk all devices of a target
588 * @starget: target whose devices we want to iterate over.
589 * @data: Opaque passed to each function call.
590 * @fn: Function to call on each device
591 *
592 * This traverses over each device of @starget. The devices have
593 * a reference that must be released by scsi_host_put when breaking
594 * out of the loop.
595 */
596void starget_for_each_device(struct scsi_target *starget, void *data,
597 void (*fn)(struct scsi_device *, void *))
598{
599 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
600 struct scsi_device *sdev;
601
602 shost_for_each_device(sdev, shost) {
603 if ((sdev->channel == starget->channel) &&
604 (sdev->id == starget->id))
605 fn(sdev, data);
606 }
607}
608EXPORT_SYMBOL(starget_for_each_device);
609
610/**
611 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
612 * @starget: target whose devices we want to iterate over.
613 * @data: parameter for callback @fn()
614 * @fn: callback function that is invoked for each device
615 *
616 * This traverses over each device of @starget. It does _not_
617 * take a reference on the scsi_device, so the whole loop must be
618 * protected by shost->host_lock.
619 *
620 * Note: The only reason why drivers would want to use this is because
621 * they need to access the device list in irq context. Otherwise you
622 * really want to use starget_for_each_device instead.
623 **/
624void __starget_for_each_device(struct scsi_target *starget, void *data,
625 void (*fn)(struct scsi_device *, void *))
626{
627 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
628 struct scsi_device *sdev;
629
630 __shost_for_each_device(sdev, shost) {
631 if ((sdev->channel == starget->channel) &&
632 (sdev->id == starget->id))
633 fn(sdev, data);
634 }
635}
636EXPORT_SYMBOL(__starget_for_each_device);
637
638/**
639 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
640 * @starget: SCSI target pointer
641 * @lun: SCSI Logical Unit Number
642 *
643 * Description: Looks up the scsi_device with the specified @lun for a given
644 * @starget. The returned scsi_device does not have an additional
645 * reference. You must hold the host's host_lock over this call and
646 * any access to the returned scsi_device. A scsi_device in state
647 * SDEV_DEL is skipped.
648 *
649 * Note: The only reason why drivers should use this is because
650 * they need to access the device list in irq context. Otherwise you
651 * really want to use scsi_device_lookup_by_target instead.
652 **/
653struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
654 u64 lun)
655{
656 struct scsi_device *sdev;
657
658 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
659 if (sdev->sdev_state == SDEV_DEL)
660 continue;
661 if (sdev->lun ==lun)
662 return sdev;
663 }
664
665 return NULL;
666}
667EXPORT_SYMBOL(__scsi_device_lookup_by_target);
668
669/**
670 * scsi_device_lookup_by_target - find a device given the target
671 * @starget: SCSI target pointer
672 * @lun: SCSI Logical Unit Number
673 *
674 * Description: Looks up the scsi_device with the specified @lun for a given
675 * @starget. The returned scsi_device has an additional reference that
676 * needs to be released with scsi_device_put once you're done with it.
677 **/
678struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
679 u64 lun)
680{
681 struct scsi_device *sdev;
682 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
683 unsigned long flags;
684
685 spin_lock_irqsave(shost->host_lock, flags);
686 sdev = __scsi_device_lookup_by_target(starget, lun);
687 if (sdev && scsi_device_get(sdev))
688 sdev = NULL;
689 spin_unlock_irqrestore(shost->host_lock, flags);
690
691 return sdev;
692}
693EXPORT_SYMBOL(scsi_device_lookup_by_target);
694
695/**
696 * __scsi_device_lookup - find a device given the host (UNLOCKED)
697 * @shost: SCSI host pointer
698 * @channel: SCSI channel (zero if only one channel)
699 * @id: SCSI target number (physical unit number)
700 * @lun: SCSI Logical Unit Number
701 *
702 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
703 * for a given host. The returned scsi_device does not have an additional
704 * reference. You must hold the host's host_lock over this call and any access
705 * to the returned scsi_device.
706 *
707 * Note: The only reason why drivers would want to use this is because
708 * they need to access the device list in irq context. Otherwise you
709 * really want to use scsi_device_lookup instead.
710 **/
711struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
712 uint channel, uint id, u64 lun)
713{
714 struct scsi_device *sdev;
715
716 list_for_each_entry(sdev, &shost->__devices, siblings) {
717 if (sdev->sdev_state == SDEV_DEL)
718 continue;
719 if (sdev->channel == channel && sdev->id == id &&
720 sdev->lun ==lun)
721 return sdev;
722 }
723
724 return NULL;
725}
726EXPORT_SYMBOL(__scsi_device_lookup);
727
728/**
729 * scsi_device_lookup - find a device given the host
730 * @shost: SCSI host pointer
731 * @channel: SCSI channel (zero if only one channel)
732 * @id: SCSI target number (physical unit number)
733 * @lun: SCSI Logical Unit Number
734 *
735 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
736 * for a given host. The returned scsi_device has an additional reference that
737 * needs to be released with scsi_device_put once you're done with it.
738 **/
739struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
740 uint channel, uint id, u64 lun)
741{
742 struct scsi_device *sdev;
743 unsigned long flags;
744
745 spin_lock_irqsave(shost->host_lock, flags);
746 sdev = __scsi_device_lookup(shost, channel, id, lun);
747 if (sdev && scsi_device_get(sdev))
748 sdev = NULL;
749 spin_unlock_irqrestore(shost->host_lock, flags);
750
751 return sdev;
752}
753EXPORT_SYMBOL(scsi_device_lookup);
754
755MODULE_DESCRIPTION("SCSI core");
756MODULE_LICENSE("GPL");
757
758module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
759MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
760
761static int __init init_scsi(void)
762{
763 int error;
764
765 error = scsi_init_procfs();
766 if (error)
767 goto cleanup_queue;
768 error = scsi_init_devinfo();
769 if (error)
770 goto cleanup_procfs;
771 error = scsi_init_hosts();
772 if (error)
773 goto cleanup_devlist;
774 error = scsi_init_sysctl();
775 if (error)
776 goto cleanup_hosts;
777 error = scsi_sysfs_register();
778 if (error)
779 goto cleanup_sysctl;
780
781 scsi_netlink_init();
782
783 printk(KERN_NOTICE "SCSI subsystem initialized\n");
784 return 0;
785
786cleanup_sysctl:
787 scsi_exit_sysctl();
788cleanup_hosts:
789 scsi_exit_hosts();
790cleanup_devlist:
791 scsi_exit_devinfo();
792cleanup_procfs:
793 scsi_exit_procfs();
794cleanup_queue:
795 scsi_exit_queue();
796 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
797 -error);
798 return error;
799}
800
801static void __exit exit_scsi(void)
802{
803 scsi_netlink_exit();
804 scsi_sysfs_unregister();
805 scsi_exit_sysctl();
806 scsi_exit_hosts();
807 scsi_exit_devinfo();
808 scsi_exit_procfs();
809 scsi_exit_queue();
810}
811
812subsys_initcall(init_scsi);
813module_exit(exit_scsi);