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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 return sdev->queue_depth;
625}
626EXPORT_SYMBOL(scsi_change_queue_depth);
627
628/**
629 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
630 * @sdev: SCSI Device in question
631 * @depth: Current number of outstanding SCSI commands on this device,
632 * not counting the one returned as QUEUE_FULL.
633 *
634 * Description: This function will track successive QUEUE_FULL events on a
635 * specific SCSI device to determine if and when there is a
636 * need to adjust the queue depth on the device.
637 *
638 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
639 * -1 - Drop back to untagged operation using host->cmd_per_lun
640 * as the untagged command depth
641 *
642 * Lock Status: None held on entry
643 *
644 * Notes: Low level drivers may call this at any time and we will do
645 * "The Right Thing." We are interrupt context safe.
646 */
647int scsi_track_queue_full(struct scsi_device *sdev, int depth)
648{
649
650 /*
651 * Don't let QUEUE_FULLs on the same
652 * jiffies count, they could all be from
653 * same event.
654 */
655 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
656 return 0;
657
658 sdev->last_queue_full_time = jiffies;
659 if (sdev->last_queue_full_depth != depth) {
660 sdev->last_queue_full_count = 1;
661 sdev->last_queue_full_depth = depth;
662 } else {
663 sdev->last_queue_full_count++;
664 }
665
666 if (sdev->last_queue_full_count <= 10)
667 return 0;
668
669 return scsi_change_queue_depth(sdev, depth);
670}
671EXPORT_SYMBOL(scsi_track_queue_full);
672
673/**
674 * scsi_vpd_inquiry - Request a device provide us with a VPD page
675 * @sdev: The device to ask
676 * @buffer: Where to put the result
677 * @page: Which Vital Product Data to return
678 * @len: The length of the buffer
679 *
680 * This is an internal helper function. You probably want to use
681 * scsi_get_vpd_page instead.
682 *
683 * Returns size of the vpd page on success or a negative error number.
684 */
685static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
686 u8 page, unsigned len)
687{
688 int result;
689 unsigned char cmd[16];
690
691 if (len < 4)
692 return -EINVAL;
693
694 cmd[0] = INQUIRY;
695 cmd[1] = 1; /* EVPD */
696 cmd[2] = page;
697 cmd[3] = len >> 8;
698 cmd[4] = len & 0xff;
699 cmd[5] = 0; /* Control byte */
700
701 /*
702 * I'm not convinced we need to try quite this hard to get VPD, but
703 * all the existing users tried this hard.
704 */
705 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
706 len, NULL, 30 * HZ, 3, NULL);
707 if (result)
708 return -EIO;
709
710 /* Sanity check that we got the page back that we asked for */
711 if (buffer[1] != page)
712 return -EIO;
713
714 return get_unaligned_be16(&buffer[2]) + 4;
715}
716
717/**
718 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
719 * @sdev: The device to ask
720 * @page: Which Vital Product Data to return
721 * @buf: where to store the VPD
722 * @buf_len: number of bytes in the VPD buffer area
723 *
724 * SCSI devices may optionally supply Vital Product Data. Each 'page'
725 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
726 * If the device supports this VPD page, this routine returns a pointer
727 * to a buffer containing the data from that page. The caller is
728 * responsible for calling kfree() on this pointer when it is no longer
729 * needed. If we cannot retrieve the VPD page this routine returns %NULL.
730 */
731int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
732 int buf_len)
733{
734 int i, result;
735
736 if (sdev->skip_vpd_pages)
737 goto fail;
738
739 /* Ask for all the pages supported by this device */
740 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len);
741 if (result < 4)
742 goto fail;
743
744 /* If the user actually wanted this page, we can skip the rest */
745 if (page == 0)
746 return 0;
747
748 for (i = 4; i < min(result, buf_len); i++)
749 if (buf[i] == page)
750 goto found;
751
752 if (i < result && i >= buf_len)
753 /* ran off the end of the buffer, give us benefit of doubt */
754 goto found;
755 /* The device claims it doesn't support the requested page */
756 goto fail;
757
758 found:
759 result = scsi_vpd_inquiry(sdev, buf, page, buf_len);
760 if (result < 0)
761 goto fail;
762
763 return 0;
764
765 fail:
766 return -EINVAL;
767}
768EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
769
770/**
771 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure
772 * @sdev: The device to ask
773 *
774 * Attach the 'Device Identification' VPD page (0x83) and the
775 * 'Unit Serial Number' VPD page (0x80) to a SCSI device
776 * structure. This information can be used to identify the device
777 * uniquely.
778 */
779void scsi_attach_vpd(struct scsi_device *sdev)
780{
781 int result, i;
782 int vpd_len = SCSI_VPD_PG_LEN;
783 int pg80_supported = 0;
784 int pg83_supported = 0;
785 unsigned char __rcu *vpd_buf, *orig_vpd_buf = NULL;
786
787 if (!scsi_device_supports_vpd(sdev))
788 return;
789
790retry_pg0:
791 vpd_buf = kmalloc(vpd_len, GFP_KERNEL);
792 if (!vpd_buf)
793 return;
794
795 /* Ask for all the pages supported by this device */
796 result = scsi_vpd_inquiry(sdev, vpd_buf, 0, vpd_len);
797 if (result < 0) {
798 kfree(vpd_buf);
799 return;
800 }
801 if (result > vpd_len) {
802 vpd_len = result;
803 kfree(vpd_buf);
804 goto retry_pg0;
805 }
806
807 for (i = 4; i < result; i++) {
808 if (vpd_buf[i] == 0x80)
809 pg80_supported = 1;
810 if (vpd_buf[i] == 0x83)
811 pg83_supported = 1;
812 }
813 kfree(vpd_buf);
814 vpd_len = SCSI_VPD_PG_LEN;
815
816 if (pg80_supported) {
817retry_pg80:
818 vpd_buf = kmalloc(vpd_len, GFP_KERNEL);
819 if (!vpd_buf)
820 return;
821
822 result = scsi_vpd_inquiry(sdev, vpd_buf, 0x80, vpd_len);
823 if (result < 0) {
824 kfree(vpd_buf);
825 return;
826 }
827 if (result > vpd_len) {
828 vpd_len = result;
829 kfree(vpd_buf);
830 goto retry_pg80;
831 }
832 mutex_lock(&sdev->inquiry_mutex);
833 orig_vpd_buf = sdev->vpd_pg80;
834 sdev->vpd_pg80_len = result;
835 rcu_assign_pointer(sdev->vpd_pg80, vpd_buf);
836 mutex_unlock(&sdev->inquiry_mutex);
837 synchronize_rcu();
838 if (orig_vpd_buf) {
839 kfree(orig_vpd_buf);
840 orig_vpd_buf = NULL;
841 }
842 vpd_len = SCSI_VPD_PG_LEN;
843 }
844
845 if (pg83_supported) {
846retry_pg83:
847 vpd_buf = kmalloc(vpd_len, GFP_KERNEL);
848 if (!vpd_buf)
849 return;
850
851 result = scsi_vpd_inquiry(sdev, vpd_buf, 0x83, vpd_len);
852 if (result < 0) {
853 kfree(vpd_buf);
854 return;
855 }
856 if (result > vpd_len) {
857 vpd_len = result;
858 kfree(vpd_buf);
859 goto retry_pg83;
860 }
861 mutex_lock(&sdev->inquiry_mutex);
862 orig_vpd_buf = sdev->vpd_pg83;
863 sdev->vpd_pg83_len = result;
864 rcu_assign_pointer(sdev->vpd_pg83, vpd_buf);
865 mutex_unlock(&sdev->inquiry_mutex);
866 synchronize_rcu();
867 if (orig_vpd_buf)
868 kfree(orig_vpd_buf);
869 }
870}
871
872/**
873 * scsi_report_opcode - Find out if a given command opcode is supported
874 * @sdev: scsi device to query
875 * @buffer: scratch buffer (must be at least 20 bytes long)
876 * @len: length of buffer
877 * @opcode: opcode for command to look up
878 *
879 * Uses the REPORT SUPPORTED OPERATION CODES to look up the given
880 * opcode. Returns -EINVAL if RSOC fails, 0 if the command opcode is
881 * unsupported and 1 if the device claims to support the command.
882 */
883int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,
884 unsigned int len, unsigned char opcode)
885{
886 unsigned char cmd[16];
887 struct scsi_sense_hdr sshdr;
888 int result;
889
890 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3)
891 return -EINVAL;
892
893 memset(cmd, 0, 16);
894 cmd[0] = MAINTENANCE_IN;
895 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES;
896 cmd[2] = 1; /* One command format */
897 cmd[3] = opcode;
898 put_unaligned_be32(len, &cmd[6]);
899 memset(buffer, 0, len);
900
901 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
902 &sshdr, 30 * HZ, 3, NULL);
903
904 if (result && scsi_sense_valid(&sshdr) &&
905 sshdr.sense_key == ILLEGAL_REQUEST &&
906 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00)
907 return -EINVAL;
908
909 if ((buffer[1] & 3) == 3) /* Command supported */
910 return 1;
911
912 return 0;
913}
914EXPORT_SYMBOL(scsi_report_opcode);
915
916/**
917 * scsi_device_get - get an additional reference to a scsi_device
918 * @sdev: device to get a reference to
919 *
920 * Description: Gets a reference to the scsi_device and increments the use count
921 * of the underlying LLDD module. You must hold host_lock of the
922 * parent Scsi_Host or already have a reference when calling this.
923 *
924 * This will fail if a device is deleted or cancelled, or when the LLD module
925 * is in the process of being unloaded.
926 */
927int scsi_device_get(struct scsi_device *sdev)
928{
929 if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL)
930 goto fail;
931 if (!get_device(&sdev->sdev_gendev))
932 goto fail;
933 if (!try_module_get(sdev->host->hostt->module))
934 goto fail_put_device;
935 return 0;
936
937fail_put_device:
938 put_device(&sdev->sdev_gendev);
939fail:
940 return -ENXIO;
941}
942EXPORT_SYMBOL(scsi_device_get);
943
944/**
945 * scsi_device_put - release a reference to a scsi_device
946 * @sdev: device to release a reference on.
947 *
948 * Description: Release a reference to the scsi_device and decrements the use
949 * count of the underlying LLDD module. The device is freed once the last
950 * user vanishes.
951 */
952void scsi_device_put(struct scsi_device *sdev)
953{
954 module_put(sdev->host->hostt->module);
955 put_device(&sdev->sdev_gendev);
956}
957EXPORT_SYMBOL(scsi_device_put);
958
959/* helper for shost_for_each_device, see that for documentation */
960struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
961 struct scsi_device *prev)
962{
963 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
964 struct scsi_device *next = NULL;
965 unsigned long flags;
966
967 spin_lock_irqsave(shost->host_lock, flags);
968 while (list->next != &shost->__devices) {
969 next = list_entry(list->next, struct scsi_device, siblings);
970 /* skip devices that we can't get a reference to */
971 if (!scsi_device_get(next))
972 break;
973 next = NULL;
974 list = list->next;
975 }
976 spin_unlock_irqrestore(shost->host_lock, flags);
977
978 if (prev)
979 scsi_device_put(prev);
980 return next;
981}
982EXPORT_SYMBOL(__scsi_iterate_devices);
983
984/**
985 * starget_for_each_device - helper to walk all devices of a target
986 * @starget: target whose devices we want to iterate over.
987 * @data: Opaque passed to each function call.
988 * @fn: Function to call on each device
989 *
990 * This traverses over each device of @starget. The devices have
991 * a reference that must be released by scsi_host_put when breaking
992 * out of the loop.
993 */
994void starget_for_each_device(struct scsi_target *starget, void *data,
995 void (*fn)(struct scsi_device *, void *))
996{
997 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
998 struct scsi_device *sdev;
999
1000 shost_for_each_device(sdev, shost) {
1001 if ((sdev->channel == starget->channel) &&
1002 (sdev->id == starget->id))
1003 fn(sdev, data);
1004 }
1005}
1006EXPORT_SYMBOL(starget_for_each_device);
1007
1008/**
1009 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
1010 * @starget: target whose devices we want to iterate over.
1011 * @data: parameter for callback @fn()
1012 * @fn: callback function that is invoked for each device
1013 *
1014 * This traverses over each device of @starget. It does _not_
1015 * take a reference on the scsi_device, so the whole loop must be
1016 * protected by shost->host_lock.
1017 *
1018 * Note: The only reason why drivers would want to use this is because
1019 * they need to access the device list in irq context. Otherwise you
1020 * really want to use starget_for_each_device instead.
1021 **/
1022void __starget_for_each_device(struct scsi_target *starget, void *data,
1023 void (*fn)(struct scsi_device *, void *))
1024{
1025 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1026 struct scsi_device *sdev;
1027
1028 __shost_for_each_device(sdev, shost) {
1029 if ((sdev->channel == starget->channel) &&
1030 (sdev->id == starget->id))
1031 fn(sdev, data);
1032 }
1033}
1034EXPORT_SYMBOL(__starget_for_each_device);
1035
1036/**
1037 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
1038 * @starget: SCSI target pointer
1039 * @lun: SCSI Logical Unit Number
1040 *
1041 * Description: Looks up the scsi_device with the specified @lun for a given
1042 * @starget. The returned scsi_device does not have an additional
1043 * reference. You must hold the host's host_lock over this call and
1044 * any access to the returned scsi_device. A scsi_device in state
1045 * SDEV_DEL is skipped.
1046 *
1047 * Note: The only reason why drivers should use this is because
1048 * they need to access the device list in irq context. Otherwise you
1049 * really want to use scsi_device_lookup_by_target instead.
1050 **/
1051struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
1052 u64 lun)
1053{
1054 struct scsi_device *sdev;
1055
1056 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
1057 if (sdev->sdev_state == SDEV_DEL)
1058 continue;
1059 if (sdev->lun ==lun)
1060 return sdev;
1061 }
1062
1063 return NULL;
1064}
1065EXPORT_SYMBOL(__scsi_device_lookup_by_target);
1066
1067/**
1068 * scsi_device_lookup_by_target - find a device given the target
1069 * @starget: SCSI target pointer
1070 * @lun: SCSI Logical Unit Number
1071 *
1072 * Description: Looks up the scsi_device with the specified @lun for a given
1073 * @starget. The returned scsi_device has an additional reference that
1074 * needs to be released with scsi_device_put once you're done with it.
1075 **/
1076struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
1077 u64 lun)
1078{
1079 struct scsi_device *sdev;
1080 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1081 unsigned long flags;
1082
1083 spin_lock_irqsave(shost->host_lock, flags);
1084 sdev = __scsi_device_lookup_by_target(starget, lun);
1085 if (sdev && scsi_device_get(sdev))
1086 sdev = NULL;
1087 spin_unlock_irqrestore(shost->host_lock, flags);
1088
1089 return sdev;
1090}
1091EXPORT_SYMBOL(scsi_device_lookup_by_target);
1092
1093/**
1094 * __scsi_device_lookup - find a device given the host (UNLOCKED)
1095 * @shost: SCSI host pointer
1096 * @channel: SCSI channel (zero if only one channel)
1097 * @id: SCSI target number (physical unit number)
1098 * @lun: SCSI Logical Unit Number
1099 *
1100 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1101 * for a given host. The returned scsi_device does not have an additional
1102 * reference. You must hold the host's host_lock over this call and any access
1103 * to the returned scsi_device.
1104 *
1105 * Note: The only reason why drivers would want to use this is because
1106 * they need to access the device list in irq context. Otherwise you
1107 * really want to use scsi_device_lookup instead.
1108 **/
1109struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
1110 uint channel, uint id, u64 lun)
1111{
1112 struct scsi_device *sdev;
1113
1114 list_for_each_entry(sdev, &shost->__devices, siblings) {
1115 if (sdev->channel == channel && sdev->id == id &&
1116 sdev->lun ==lun)
1117 return sdev;
1118 }
1119
1120 return NULL;
1121}
1122EXPORT_SYMBOL(__scsi_device_lookup);
1123
1124/**
1125 * scsi_device_lookup - find a device given the host
1126 * @shost: SCSI host pointer
1127 * @channel: SCSI channel (zero if only one channel)
1128 * @id: SCSI target number (physical unit number)
1129 * @lun: SCSI Logical Unit Number
1130 *
1131 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1132 * for a given host. The returned scsi_device has an additional reference that
1133 * needs to be released with scsi_device_put once you're done with it.
1134 **/
1135struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1136 uint channel, uint id, u64 lun)
1137{
1138 struct scsi_device *sdev;
1139 unsigned long flags;
1140
1141 spin_lock_irqsave(shost->host_lock, flags);
1142 sdev = __scsi_device_lookup(shost, channel, id, lun);
1143 if (sdev && scsi_device_get(sdev))
1144 sdev = NULL;
1145 spin_unlock_irqrestore(shost->host_lock, flags);
1146
1147 return sdev;
1148}
1149EXPORT_SYMBOL(scsi_device_lookup);
1150
1151MODULE_DESCRIPTION("SCSI core");
1152MODULE_LICENSE("GPL");
1153
1154module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1155MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1156
1157#ifdef CONFIG_SCSI_MQ_DEFAULT
1158bool scsi_use_blk_mq = true;
1159#else
1160bool scsi_use_blk_mq = false;
1161#endif
1162module_param_named(use_blk_mq, scsi_use_blk_mq, bool, S_IWUSR | S_IRUGO);
1163
1164static int __init init_scsi(void)
1165{
1166 int error;
1167
1168 error = scsi_init_queue();
1169 if (error)
1170 return error;
1171 error = scsi_init_procfs();
1172 if (error)
1173 goto cleanup_queue;
1174 error = scsi_init_devinfo();
1175 if (error)
1176 goto cleanup_procfs;
1177 error = scsi_init_hosts();
1178 if (error)
1179 goto cleanup_devlist;
1180 error = scsi_init_sysctl();
1181 if (error)
1182 goto cleanup_hosts;
1183 error = scsi_sysfs_register();
1184 if (error)
1185 goto cleanup_sysctl;
1186
1187 scsi_netlink_init();
1188
1189 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1190 return 0;
1191
1192cleanup_sysctl:
1193 scsi_exit_sysctl();
1194cleanup_hosts:
1195 scsi_exit_hosts();
1196cleanup_devlist:
1197 scsi_exit_devinfo();
1198cleanup_procfs:
1199 scsi_exit_procfs();
1200cleanup_queue:
1201 scsi_exit_queue();
1202 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1203 -error);
1204 return error;
1205}
1206
1207static void __exit exit_scsi(void)
1208{
1209 scsi_netlink_exit();
1210 scsi_sysfs_unregister();
1211 scsi_exit_sysctl();
1212 scsi_exit_hosts();
1213 scsi_exit_devinfo();
1214 scsi_exit_procfs();
1215 scsi_exit_queue();
1216 async_unregister_domain(&scsi_sd_probe_domain);
1217}
1218
1219subsys_initcall(init_scsi);
1220module_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/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#ifdef CONFIG_SCSI_LOGGING
89void scsi_log_send(struct scsi_cmnd *cmd)
90{
91 unsigned int level;
92
93 /*
94 * If ML QUEUE log level is greater than or equal to:
95 *
96 * 1: nothing (match completion)
97 *
98 * 2: log opcode + command of all commands + cmd address
99 *
100 * 3: same as 2
101 *
102 * 4: same as 3
103 */
104 if (unlikely(scsi_logging_level)) {
105 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
106 SCSI_LOG_MLQUEUE_BITS);
107 if (level > 1) {
108 scmd_printk(KERN_INFO, cmd,
109 "Send: scmd 0x%p\n", cmd);
110 scsi_print_command(cmd);
111 }
112 }
113}
114
115void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
116{
117 unsigned int level;
118
119 /*
120 * If ML COMPLETE log level is greater than or equal to:
121 *
122 * 1: log disposition, result, opcode + command, and conditionally
123 * sense data for failures or non SUCCESS dispositions.
124 *
125 * 2: same as 1 but for all command completions.
126 *
127 * 3: same as 2
128 *
129 * 4: same as 3 plus dump extra junk
130 */
131 if (unlikely(scsi_logging_level)) {
132 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
133 SCSI_LOG_MLCOMPLETE_BITS);
134 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
135 (level > 1)) {
136 scsi_print_result(cmd, "Done", disposition);
137 scsi_print_command(cmd);
138 if (scsi_status_is_check_condition(cmd->result))
139 scsi_print_sense(cmd);
140 if (level > 3)
141 scmd_printk(KERN_INFO, cmd,
142 "scsi host busy %d failed %d\n",
143 scsi_host_busy(cmd->device->host),
144 cmd->device->host->host_failed);
145 }
146 }
147}
148#endif
149
150/**
151 * scsi_finish_command - cleanup and pass command back to upper layer
152 * @cmd: the command
153 *
154 * Description: Pass command off to upper layer for finishing of I/O
155 * request, waking processes that are waiting on results,
156 * etc.
157 */
158void scsi_finish_command(struct scsi_cmnd *cmd)
159{
160 struct scsi_device *sdev = cmd->device;
161 struct scsi_target *starget = scsi_target(sdev);
162 struct Scsi_Host *shost = sdev->host;
163 struct scsi_driver *drv;
164 unsigned int good_bytes;
165
166 scsi_device_unbusy(sdev, cmd);
167
168 /*
169 * Clear the flags that say that the device/target/host is no longer
170 * capable of accepting new commands.
171 */
172 if (atomic_read(&shost->host_blocked))
173 atomic_set(&shost->host_blocked, 0);
174 if (atomic_read(&starget->target_blocked))
175 atomic_set(&starget->target_blocked, 0);
176 if (atomic_read(&sdev->device_blocked))
177 atomic_set(&sdev->device_blocked, 0);
178
179 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
180 "Notifying upper driver of completion "
181 "(result %x)\n", cmd->result));
182
183 good_bytes = scsi_bufflen(cmd);
184 if (!blk_rq_is_passthrough(scsi_cmd_to_rq(cmd))) {
185 int old_good_bytes = good_bytes;
186 drv = scsi_cmd_to_driver(cmd);
187 if (drv->done)
188 good_bytes = drv->done(cmd);
189 /*
190 * USB may not give sense identifying bad sector and
191 * simply return a residue instead, so subtract off the
192 * residue if drv->done() error processing indicates no
193 * change to the completion length.
194 */
195 if (good_bytes == old_good_bytes)
196 good_bytes -= scsi_get_resid(cmd);
197 }
198 scsi_io_completion(cmd, good_bytes);
199}
200
201
202/*
203 * 4096 is big enough for saturating fast SCSI LUNs.
204 */
205int scsi_device_max_queue_depth(struct scsi_device *sdev)
206{
207 return min_t(int, sdev->host->can_queue, 4096);
208}
209
210/**
211 * scsi_change_queue_depth - change a device's queue depth
212 * @sdev: SCSI Device in question
213 * @depth: number of commands allowed to be queued to the driver
214 *
215 * Sets the device queue depth and returns the new value.
216 */
217int scsi_change_queue_depth(struct scsi_device *sdev, int depth)
218{
219 depth = min_t(int, depth, scsi_device_max_queue_depth(sdev));
220
221 if (depth > 0) {
222 sdev->queue_depth = depth;
223 wmb();
224 }
225
226 if (sdev->request_queue)
227 blk_set_queue_depth(sdev->request_queue, depth);
228
229 sbitmap_resize(&sdev->budget_map, sdev->queue_depth);
230
231 return sdev->queue_depth;
232}
233EXPORT_SYMBOL(scsi_change_queue_depth);
234
235/**
236 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
237 * @sdev: SCSI Device in question
238 * @depth: Current number of outstanding SCSI commands on this device,
239 * not counting the one returned as QUEUE_FULL.
240 *
241 * Description: This function will track successive QUEUE_FULL events on a
242 * specific SCSI device to determine if and when there is a
243 * need to adjust the queue depth on the device.
244 *
245 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
246 * -1 - Drop back to untagged operation using host->cmd_per_lun
247 * as the untagged command depth
248 *
249 * Lock Status: None held on entry
250 *
251 * Notes: Low level drivers may call this at any time and we will do
252 * "The Right Thing." We are interrupt context safe.
253 */
254int scsi_track_queue_full(struct scsi_device *sdev, int depth)
255{
256
257 /*
258 * Don't let QUEUE_FULLs on the same
259 * jiffies count, they could all be from
260 * same event.
261 */
262 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
263 return 0;
264
265 sdev->last_queue_full_time = jiffies;
266 if (sdev->last_queue_full_depth != depth) {
267 sdev->last_queue_full_count = 1;
268 sdev->last_queue_full_depth = depth;
269 } else {
270 sdev->last_queue_full_count++;
271 }
272
273 if (sdev->last_queue_full_count <= 10)
274 return 0;
275
276 return scsi_change_queue_depth(sdev, depth);
277}
278EXPORT_SYMBOL(scsi_track_queue_full);
279
280/**
281 * scsi_vpd_inquiry - Request a device provide us with a VPD page
282 * @sdev: The device to ask
283 * @buffer: Where to put the result
284 * @page: Which Vital Product Data to return
285 * @len: The length of the buffer
286 *
287 * This is an internal helper function. You probably want to use
288 * scsi_get_vpd_page instead.
289 *
290 * Returns size of the vpd page on success or a negative error number.
291 */
292static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
293 u8 page, unsigned len)
294{
295 int result;
296 unsigned char cmd[16];
297
298 if (len < 4)
299 return -EINVAL;
300
301 cmd[0] = INQUIRY;
302 cmd[1] = 1; /* EVPD */
303 cmd[2] = page;
304 cmd[3] = len >> 8;
305 cmd[4] = len & 0xff;
306 cmd[5] = 0; /* Control byte */
307
308 /*
309 * I'm not convinced we need to try quite this hard to get VPD, but
310 * all the existing users tried this hard.
311 */
312 result = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_IN, buffer, len,
313 30 * HZ, 3, NULL);
314 if (result)
315 return -EIO;
316
317 /*
318 * Sanity check that we got the page back that we asked for and that
319 * the page size is not 0.
320 */
321 if (buffer[1] != page)
322 return -EIO;
323
324 result = get_unaligned_be16(&buffer[2]);
325 if (!result)
326 return -EIO;
327
328 return result + 4;
329}
330
331enum scsi_vpd_parameters {
332 SCSI_VPD_HEADER_SIZE = 4,
333 SCSI_VPD_LIST_SIZE = 36,
334};
335
336static int scsi_get_vpd_size(struct scsi_device *sdev, u8 page)
337{
338 unsigned char vpd[SCSI_VPD_LIST_SIZE] __aligned(4);
339 int result;
340
341 if (sdev->no_vpd_size)
342 return SCSI_DEFAULT_VPD_LEN;
343
344 /*
345 * Fetch the supported pages VPD and validate that the requested page
346 * number is present.
347 */
348 if (page != 0) {
349 result = scsi_vpd_inquiry(sdev, vpd, 0, sizeof(vpd));
350 if (result < SCSI_VPD_HEADER_SIZE)
351 return 0;
352
353 if (result > sizeof(vpd)) {
354 dev_warn_once(&sdev->sdev_gendev,
355 "%s: long VPD page 0 length: %d bytes\n",
356 __func__, result);
357 result = sizeof(vpd);
358 }
359
360 result -= SCSI_VPD_HEADER_SIZE;
361 if (!memchr(&vpd[SCSI_VPD_HEADER_SIZE], page, result))
362 return 0;
363 }
364 /*
365 * Fetch the VPD page header to find out how big the page
366 * is. This is done to prevent problems on legacy devices
367 * which can not handle allocation lengths as large as
368 * potentially requested by the caller.
369 */
370 result = scsi_vpd_inquiry(sdev, vpd, page, SCSI_VPD_HEADER_SIZE);
371 if (result < 0)
372 return 0;
373
374 if (result < SCSI_VPD_HEADER_SIZE) {
375 dev_warn_once(&sdev->sdev_gendev,
376 "%s: short VPD page 0x%02x length: %d bytes\n",
377 __func__, page, result);
378 return 0;
379 }
380
381 return result;
382}
383
384/**
385 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
386 * @sdev: The device to ask
387 * @page: Which Vital Product Data to return
388 * @buf: where to store the VPD
389 * @buf_len: number of bytes in the VPD buffer area
390 *
391 * SCSI devices may optionally supply Vital Product Data. Each 'page'
392 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
393 * If the device supports this VPD page, this routine fills @buf
394 * with the data from that page and return 0. If the VPD page is not
395 * supported or its content cannot be retrieved, -EINVAL is returned.
396 */
397int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
398 int buf_len)
399{
400 int result, vpd_len;
401
402 if (!scsi_device_supports_vpd(sdev))
403 return -EINVAL;
404
405 vpd_len = scsi_get_vpd_size(sdev, page);
406 if (vpd_len <= 0)
407 return -EINVAL;
408
409 vpd_len = min(vpd_len, buf_len);
410
411 /*
412 * Fetch the actual page. Since the appropriate size was reported
413 * by the device it is now safe to ask for something bigger.
414 */
415 memset(buf, 0, buf_len);
416 result = scsi_vpd_inquiry(sdev, buf, page, vpd_len);
417 if (result < 0)
418 return -EINVAL;
419 else if (result > vpd_len)
420 dev_warn_once(&sdev->sdev_gendev,
421 "%s: VPD page 0x%02x result %d > %d bytes\n",
422 __func__, page, result, vpd_len);
423
424 return 0;
425}
426EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
427
428/**
429 * scsi_get_vpd_buf - Get Vital Product Data from a SCSI device
430 * @sdev: The device to ask
431 * @page: Which Vital Product Data to return
432 *
433 * Returns %NULL upon failure.
434 */
435static struct scsi_vpd *scsi_get_vpd_buf(struct scsi_device *sdev, u8 page)
436{
437 struct scsi_vpd *vpd_buf;
438 int vpd_len, result;
439
440 vpd_len = scsi_get_vpd_size(sdev, page);
441 if (vpd_len <= 0)
442 return NULL;
443
444retry_pg:
445 /*
446 * Fetch the actual page. Since the appropriate size was reported
447 * by the device it is now safe to ask for something bigger.
448 */
449 vpd_buf = kmalloc(sizeof(*vpd_buf) + vpd_len, GFP_KERNEL);
450 if (!vpd_buf)
451 return NULL;
452
453 result = scsi_vpd_inquiry(sdev, vpd_buf->data, page, vpd_len);
454 if (result < 0) {
455 kfree(vpd_buf);
456 return NULL;
457 }
458 if (result > vpd_len) {
459 dev_warn_once(&sdev->sdev_gendev,
460 "%s: VPD page 0x%02x result %d > %d bytes\n",
461 __func__, page, result, vpd_len);
462 vpd_len = result;
463 kfree(vpd_buf);
464 goto retry_pg;
465 }
466
467 vpd_buf->len = result;
468
469 return vpd_buf;
470}
471
472static void scsi_update_vpd_page(struct scsi_device *sdev, u8 page,
473 struct scsi_vpd __rcu **sdev_vpd_buf)
474{
475 struct scsi_vpd *vpd_buf;
476
477 vpd_buf = scsi_get_vpd_buf(sdev, page);
478 if (!vpd_buf)
479 return;
480
481 mutex_lock(&sdev->inquiry_mutex);
482 vpd_buf = rcu_replace_pointer(*sdev_vpd_buf, vpd_buf,
483 lockdep_is_held(&sdev->inquiry_mutex));
484 mutex_unlock(&sdev->inquiry_mutex);
485
486 if (vpd_buf)
487 kfree_rcu(vpd_buf, rcu);
488}
489
490/**
491 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure
492 * @sdev: The device to ask
493 *
494 * Attach the 'Device Identification' VPD page (0x83) and the
495 * 'Unit Serial Number' VPD page (0x80) to a SCSI device
496 * structure. This information can be used to identify the device
497 * uniquely.
498 */
499void scsi_attach_vpd(struct scsi_device *sdev)
500{
501 int i;
502 struct scsi_vpd *vpd_buf;
503
504 if (!scsi_device_supports_vpd(sdev))
505 return;
506
507 /* Ask for all the pages supported by this device */
508 vpd_buf = scsi_get_vpd_buf(sdev, 0);
509 if (!vpd_buf)
510 return;
511
512 for (i = 4; i < vpd_buf->len; i++) {
513 if (vpd_buf->data[i] == 0x0)
514 scsi_update_vpd_page(sdev, 0x0, &sdev->vpd_pg0);
515 if (vpd_buf->data[i] == 0x80)
516 scsi_update_vpd_page(sdev, 0x80, &sdev->vpd_pg80);
517 if (vpd_buf->data[i] == 0x83)
518 scsi_update_vpd_page(sdev, 0x83, &sdev->vpd_pg83);
519 if (vpd_buf->data[i] == 0x89)
520 scsi_update_vpd_page(sdev, 0x89, &sdev->vpd_pg89);
521 if (vpd_buf->data[i] == 0xb0)
522 scsi_update_vpd_page(sdev, 0xb0, &sdev->vpd_pgb0);
523 if (vpd_buf->data[i] == 0xb1)
524 scsi_update_vpd_page(sdev, 0xb1, &sdev->vpd_pgb1);
525 if (vpd_buf->data[i] == 0xb2)
526 scsi_update_vpd_page(sdev, 0xb2, &sdev->vpd_pgb2);
527 if (vpd_buf->data[i] == 0xb7)
528 scsi_update_vpd_page(sdev, 0xb7, &sdev->vpd_pgb7);
529 }
530 kfree(vpd_buf);
531}
532
533/**
534 * scsi_report_opcode - Find out if a given command is supported
535 * @sdev: scsi device to query
536 * @buffer: scratch buffer (must be at least 20 bytes long)
537 * @len: length of buffer
538 * @opcode: opcode for the command to look up
539 * @sa: service action for the command to look up
540 *
541 * Uses the REPORT SUPPORTED OPERATION CODES to check support for the
542 * command identified with @opcode and @sa. If the command does not
543 * have a service action, @sa must be 0. Returns -EINVAL if RSOC fails,
544 * 0 if the command is not supported and 1 if the device claims to
545 * support the command.
546 */
547int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,
548 unsigned int len, unsigned char opcode,
549 unsigned short sa)
550{
551 unsigned char cmd[16];
552 struct scsi_sense_hdr sshdr;
553 int result, request_len;
554 const struct scsi_exec_args exec_args = {
555 .sshdr = &sshdr,
556 };
557
558 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3)
559 return -EINVAL;
560
561 /* RSOC header + size of command we are asking about */
562 request_len = 4 + COMMAND_SIZE(opcode);
563 if (request_len > len) {
564 dev_warn_once(&sdev->sdev_gendev,
565 "%s: len %u bytes, opcode 0x%02x needs %u\n",
566 __func__, len, opcode, request_len);
567 return -EINVAL;
568 }
569
570 memset(cmd, 0, 16);
571 cmd[0] = MAINTENANCE_IN;
572 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES;
573 if (!sa) {
574 cmd[2] = 1; /* One command format */
575 cmd[3] = opcode;
576 } else {
577 cmd[2] = 3; /* One command format with service action */
578 cmd[3] = opcode;
579 put_unaligned_be16(sa, &cmd[4]);
580 }
581 put_unaligned_be32(request_len, &cmd[6]);
582 memset(buffer, 0, len);
583
584 result = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_IN, buffer,
585 request_len, 30 * HZ, 3, &exec_args);
586 if (result < 0)
587 return result;
588 if (result && scsi_sense_valid(&sshdr) &&
589 sshdr.sense_key == ILLEGAL_REQUEST &&
590 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00)
591 return -EINVAL;
592
593 if ((buffer[1] & 3) == 3) /* Command supported */
594 return 1;
595
596 return 0;
597}
598EXPORT_SYMBOL(scsi_report_opcode);
599
600#define SCSI_CDL_CHECK_BUF_LEN 64
601
602static bool scsi_cdl_check_cmd(struct scsi_device *sdev, u8 opcode, u16 sa,
603 unsigned char *buf)
604{
605 int ret;
606 u8 cdlp;
607
608 /* Check operation code */
609 ret = scsi_report_opcode(sdev, buf, SCSI_CDL_CHECK_BUF_LEN, opcode, sa);
610 if (ret <= 0)
611 return false;
612
613 if ((buf[1] & 0x03) != 0x03)
614 return false;
615
616 /*
617 * See SPC-6, One_command parameter data format for
618 * REPORT SUPPORTED OPERATION CODES. We have the following cases
619 * depending on rwcdlp (buf[0] & 0x01) value:
620 * - rwcdlp == 0: then cdlp indicates support for the A mode page when
621 * it is equal to 1 and for the B mode page when it is
622 * equal to 2.
623 * - rwcdlp == 1: then cdlp indicates support for the T2A mode page
624 * when it is equal to 1 and for the T2B mode page when
625 * it is equal to 2.
626 * Overall, to detect support for command duration limits, we only need
627 * to check that cdlp is 1 or 2.
628 */
629 cdlp = (buf[1] & 0x18) >> 3;
630
631 return cdlp == 0x01 || cdlp == 0x02;
632}
633
634/**
635 * scsi_cdl_check - Check if a SCSI device supports Command Duration Limits
636 * @sdev: The device to check
637 */
638void scsi_cdl_check(struct scsi_device *sdev)
639{
640 bool cdl_supported;
641 unsigned char *buf;
642
643 /*
644 * Support for CDL was defined in SPC-5. Ignore devices reporting an
645 * lower SPC version. This also avoids problems with old drives choking
646 * on MAINTENANCE_IN / MI_REPORT_SUPPORTED_OPERATION_CODES with a
647 * service action specified, as done in scsi_cdl_check_cmd().
648 */
649 if (sdev->scsi_level < SCSI_SPC_5) {
650 sdev->cdl_supported = 0;
651 return;
652 }
653
654 buf = kmalloc(SCSI_CDL_CHECK_BUF_LEN, GFP_KERNEL);
655 if (!buf) {
656 sdev->cdl_supported = 0;
657 return;
658 }
659
660 /* Check support for READ_16, WRITE_16, READ_32 and WRITE_32 commands */
661 cdl_supported =
662 scsi_cdl_check_cmd(sdev, READ_16, 0, buf) ||
663 scsi_cdl_check_cmd(sdev, WRITE_16, 0, buf) ||
664 scsi_cdl_check_cmd(sdev, VARIABLE_LENGTH_CMD, READ_32, buf) ||
665 scsi_cdl_check_cmd(sdev, VARIABLE_LENGTH_CMD, WRITE_32, buf);
666 if (cdl_supported) {
667 /*
668 * We have CDL support: force the use of READ16/WRITE16.
669 * READ32 and WRITE32 will be used for devices that support
670 * the T10_PI_TYPE2_PROTECTION protection type.
671 */
672 sdev->use_16_for_rw = 1;
673 sdev->use_10_for_rw = 0;
674
675 sdev->cdl_supported = 1;
676
677 /*
678 * If the device supports CDL, make sure that the current drive
679 * feature status is consistent with the user controlled
680 * cdl_enable state.
681 */
682 scsi_cdl_enable(sdev, sdev->cdl_enable);
683 } else {
684 sdev->cdl_supported = 0;
685 }
686
687 kfree(buf);
688}
689
690/**
691 * scsi_cdl_enable - Enable or disable a SCSI device supports for Command
692 * Duration Limits
693 * @sdev: The target device
694 * @enable: the target state
695 */
696int scsi_cdl_enable(struct scsi_device *sdev, bool enable)
697{
698 struct scsi_mode_data data;
699 struct scsi_sense_hdr sshdr;
700 struct scsi_vpd *vpd;
701 bool is_ata = false;
702 char buf[64];
703 int ret;
704
705 if (!sdev->cdl_supported)
706 return -EOPNOTSUPP;
707
708 rcu_read_lock();
709 vpd = rcu_dereference(sdev->vpd_pg89);
710 if (vpd)
711 is_ata = true;
712 rcu_read_unlock();
713
714 /*
715 * For ATA devices, CDL needs to be enabled with a SET FEATURES command.
716 */
717 if (is_ata) {
718 char *buf_data;
719 int len;
720
721 ret = scsi_mode_sense(sdev, 0x08, 0x0a, 0xf2, buf, sizeof(buf),
722 5 * HZ, 3, &data, NULL);
723 if (ret)
724 return -EINVAL;
725
726 /* Enable CDL using the ATA feature page */
727 len = min_t(size_t, sizeof(buf),
728 data.length - data.header_length -
729 data.block_descriptor_length);
730 buf_data = buf + data.header_length +
731 data.block_descriptor_length;
732 if (enable)
733 buf_data[4] = 0x02;
734 else
735 buf_data[4] = 0;
736
737 ret = scsi_mode_select(sdev, 1, 0, buf_data, len, 5 * HZ, 3,
738 &data, &sshdr);
739 if (ret) {
740 if (ret > 0 && scsi_sense_valid(&sshdr))
741 scsi_print_sense_hdr(sdev,
742 dev_name(&sdev->sdev_gendev), &sshdr);
743 return ret;
744 }
745 }
746
747 sdev->cdl_enable = enable;
748
749 return 0;
750}
751
752/**
753 * scsi_device_get - get an additional reference to a scsi_device
754 * @sdev: device to get a reference to
755 *
756 * Description: Gets a reference to the scsi_device and increments the use count
757 * of the underlying LLDD module. You must hold host_lock of the
758 * parent Scsi_Host or already have a reference when calling this.
759 *
760 * This will fail if a device is deleted or cancelled, or when the LLD module
761 * is in the process of being unloaded.
762 */
763int scsi_device_get(struct scsi_device *sdev)
764{
765 if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL)
766 goto fail;
767 if (!try_module_get(sdev->host->hostt->module))
768 goto fail;
769 if (!get_device(&sdev->sdev_gendev))
770 goto fail_put_module;
771 return 0;
772
773fail_put_module:
774 module_put(sdev->host->hostt->module);
775fail:
776 return -ENXIO;
777}
778EXPORT_SYMBOL(scsi_device_get);
779
780/**
781 * scsi_device_put - release a reference to a scsi_device
782 * @sdev: device to release a reference on.
783 *
784 * Description: Release a reference to the scsi_device and decrements the use
785 * count of the underlying LLDD module. The device is freed once the last
786 * user vanishes.
787 */
788void scsi_device_put(struct scsi_device *sdev)
789{
790 struct module *mod = sdev->host->hostt->module;
791
792 put_device(&sdev->sdev_gendev);
793 module_put(mod);
794}
795EXPORT_SYMBOL(scsi_device_put);
796
797/* helper for shost_for_each_device, see that for documentation */
798struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
799 struct scsi_device *prev)
800{
801 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
802 struct scsi_device *next = NULL;
803 unsigned long flags;
804
805 spin_lock_irqsave(shost->host_lock, flags);
806 while (list->next != &shost->__devices) {
807 next = list_entry(list->next, struct scsi_device, siblings);
808 /* skip devices that we can't get a reference to */
809 if (!scsi_device_get(next))
810 break;
811 next = NULL;
812 list = list->next;
813 }
814 spin_unlock_irqrestore(shost->host_lock, flags);
815
816 if (prev)
817 scsi_device_put(prev);
818 return next;
819}
820EXPORT_SYMBOL(__scsi_iterate_devices);
821
822/**
823 * starget_for_each_device - helper to walk all devices of a target
824 * @starget: target whose devices we want to iterate over.
825 * @data: Opaque passed to each function call.
826 * @fn: Function to call on each device
827 *
828 * This traverses over each device of @starget. The devices have
829 * a reference that must be released by scsi_host_put when breaking
830 * out of the loop.
831 */
832void starget_for_each_device(struct scsi_target *starget, void *data,
833 void (*fn)(struct scsi_device *, void *))
834{
835 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
836 struct scsi_device *sdev;
837
838 shost_for_each_device(sdev, shost) {
839 if ((sdev->channel == starget->channel) &&
840 (sdev->id == starget->id))
841 fn(sdev, data);
842 }
843}
844EXPORT_SYMBOL(starget_for_each_device);
845
846/**
847 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
848 * @starget: target whose devices we want to iterate over.
849 * @data: parameter for callback @fn()
850 * @fn: callback function that is invoked for each device
851 *
852 * This traverses over each device of @starget. It does _not_
853 * take a reference on the scsi_device, so the whole loop must be
854 * protected by shost->host_lock.
855 *
856 * Note: The only reason why drivers would want to use this is because
857 * they need to access the device list in irq context. Otherwise you
858 * really want to use starget_for_each_device instead.
859 **/
860void __starget_for_each_device(struct scsi_target *starget, void *data,
861 void (*fn)(struct scsi_device *, void *))
862{
863 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
864 struct scsi_device *sdev;
865
866 __shost_for_each_device(sdev, shost) {
867 if ((sdev->channel == starget->channel) &&
868 (sdev->id == starget->id))
869 fn(sdev, data);
870 }
871}
872EXPORT_SYMBOL(__starget_for_each_device);
873
874/**
875 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
876 * @starget: SCSI target pointer
877 * @lun: SCSI Logical Unit Number
878 *
879 * Description: Looks up the scsi_device with the specified @lun for a given
880 * @starget. The returned scsi_device does not have an additional
881 * reference. You must hold the host's host_lock over this call and
882 * any access to the returned scsi_device. A scsi_device in state
883 * SDEV_DEL is skipped.
884 *
885 * Note: The only reason why drivers should use this is because
886 * they need to access the device list in irq context. Otherwise you
887 * really want to use scsi_device_lookup_by_target instead.
888 **/
889struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
890 u64 lun)
891{
892 struct scsi_device *sdev;
893
894 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
895 if (sdev->sdev_state == SDEV_DEL)
896 continue;
897 if (sdev->lun ==lun)
898 return sdev;
899 }
900
901 return NULL;
902}
903EXPORT_SYMBOL(__scsi_device_lookup_by_target);
904
905/**
906 * scsi_device_lookup_by_target - find a device given the target
907 * @starget: SCSI target pointer
908 * @lun: SCSI Logical Unit Number
909 *
910 * Description: Looks up the scsi_device with the specified @lun for a given
911 * @starget. The returned scsi_device has an additional reference that
912 * needs to be released with scsi_device_put once you're done with it.
913 **/
914struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
915 u64 lun)
916{
917 struct scsi_device *sdev;
918 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
919 unsigned long flags;
920
921 spin_lock_irqsave(shost->host_lock, flags);
922 sdev = __scsi_device_lookup_by_target(starget, lun);
923 if (sdev && scsi_device_get(sdev))
924 sdev = NULL;
925 spin_unlock_irqrestore(shost->host_lock, flags);
926
927 return sdev;
928}
929EXPORT_SYMBOL(scsi_device_lookup_by_target);
930
931/**
932 * __scsi_device_lookup - find a device given the host (UNLOCKED)
933 * @shost: SCSI host pointer
934 * @channel: SCSI channel (zero if only one channel)
935 * @id: SCSI target number (physical unit number)
936 * @lun: SCSI Logical Unit Number
937 *
938 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
939 * for a given host. The returned scsi_device does not have an additional
940 * reference. You must hold the host's host_lock over this call and any access
941 * to the returned scsi_device.
942 *
943 * Note: The only reason why drivers would want to use this is because
944 * they need to access the device list in irq context. Otherwise you
945 * really want to use scsi_device_lookup instead.
946 **/
947struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
948 uint channel, uint id, u64 lun)
949{
950 struct scsi_device *sdev;
951
952 list_for_each_entry(sdev, &shost->__devices, siblings) {
953 if (sdev->sdev_state == SDEV_DEL)
954 continue;
955 if (sdev->channel == channel && sdev->id == id &&
956 sdev->lun ==lun)
957 return sdev;
958 }
959
960 return NULL;
961}
962EXPORT_SYMBOL(__scsi_device_lookup);
963
964/**
965 * scsi_device_lookup - find a device given the host
966 * @shost: SCSI host pointer
967 * @channel: SCSI channel (zero if only one channel)
968 * @id: SCSI target number (physical unit number)
969 * @lun: SCSI Logical Unit Number
970 *
971 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
972 * for a given host. The returned scsi_device has an additional reference that
973 * needs to be released with scsi_device_put once you're done with it.
974 **/
975struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
976 uint channel, uint id, u64 lun)
977{
978 struct scsi_device *sdev;
979 unsigned long flags;
980
981 spin_lock_irqsave(shost->host_lock, flags);
982 sdev = __scsi_device_lookup(shost, channel, id, lun);
983 if (sdev && scsi_device_get(sdev))
984 sdev = NULL;
985 spin_unlock_irqrestore(shost->host_lock, flags);
986
987 return sdev;
988}
989EXPORT_SYMBOL(scsi_device_lookup);
990
991MODULE_DESCRIPTION("SCSI core");
992MODULE_LICENSE("GPL");
993
994module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
995MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
996
997static int __init init_scsi(void)
998{
999 int error;
1000
1001 error = scsi_init_procfs();
1002 if (error)
1003 goto cleanup_queue;
1004 error = scsi_init_devinfo();
1005 if (error)
1006 goto cleanup_procfs;
1007 error = scsi_init_hosts();
1008 if (error)
1009 goto cleanup_devlist;
1010 error = scsi_init_sysctl();
1011 if (error)
1012 goto cleanup_hosts;
1013 error = scsi_sysfs_register();
1014 if (error)
1015 goto cleanup_sysctl;
1016
1017 scsi_netlink_init();
1018
1019 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1020 return 0;
1021
1022cleanup_sysctl:
1023 scsi_exit_sysctl();
1024cleanup_hosts:
1025 scsi_exit_hosts();
1026cleanup_devlist:
1027 scsi_exit_devinfo();
1028cleanup_procfs:
1029 scsi_exit_procfs();
1030cleanup_queue:
1031 scsi_exit_queue();
1032 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1033 -error);
1034 return error;
1035}
1036
1037static void __exit exit_scsi(void)
1038{
1039 scsi_netlink_exit();
1040 scsi_sysfs_unregister();
1041 scsi_exit_sysctl();
1042 scsi_exit_hosts();
1043 scsi_exit_devinfo();
1044 scsi_exit_procfs();
1045 scsi_exit_queue();
1046}
1047
1048subsys_initcall(init_scsi);
1049module_exit(exit_scsi);