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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 1999 Eric Youngdale
4 * Copyright (C) 2014 Christoph Hellwig
5 *
6 * SCSI queueing library.
7 * Initial versions: Eric Youngdale (eric@andante.org).
8 * Based upon conversations with large numbers
9 * of people at Linux Expo.
10 */
11
12#include <linux/bio.h>
13#include <linux/bitops.h>
14#include <linux/blkdev.h>
15#include <linux/completion.h>
16#include <linux/kernel.h>
17#include <linux/export.h>
18#include <linux/init.h>
19#include <linux/pci.h>
20#include <linux/delay.h>
21#include <linux/hardirq.h>
22#include <linux/scatterlist.h>
23#include <linux/blk-mq.h>
24#include <linux/blk-integrity.h>
25#include <linux/ratelimit.h>
26#include <asm/unaligned.h>
27
28#include <scsi/scsi.h>
29#include <scsi/scsi_cmnd.h>
30#include <scsi/scsi_dbg.h>
31#include <scsi/scsi_device.h>
32#include <scsi/scsi_driver.h>
33#include <scsi/scsi_eh.h>
34#include <scsi/scsi_host.h>
35#include <scsi/scsi_transport.h> /* __scsi_init_queue() */
36#include <scsi/scsi_dh.h>
37
38#include <trace/events/scsi.h>
39
40#include "scsi_debugfs.h"
41#include "scsi_priv.h"
42#include "scsi_logging.h"
43
44/*
45 * Size of integrity metadata is usually small, 1 inline sg should
46 * cover normal cases.
47 */
48#ifdef CONFIG_ARCH_NO_SG_CHAIN
49#define SCSI_INLINE_PROT_SG_CNT 0
50#define SCSI_INLINE_SG_CNT 0
51#else
52#define SCSI_INLINE_PROT_SG_CNT 1
53#define SCSI_INLINE_SG_CNT 2
54#endif
55
56static struct kmem_cache *scsi_sense_cache;
57static DEFINE_MUTEX(scsi_sense_cache_mutex);
58
59static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd);
60
61int scsi_init_sense_cache(struct Scsi_Host *shost)
62{
63 int ret = 0;
64
65 mutex_lock(&scsi_sense_cache_mutex);
66 if (!scsi_sense_cache) {
67 scsi_sense_cache =
68 kmem_cache_create_usercopy("scsi_sense_cache",
69 SCSI_SENSE_BUFFERSIZE, 0, SLAB_HWCACHE_ALIGN,
70 0, SCSI_SENSE_BUFFERSIZE, NULL);
71 if (!scsi_sense_cache)
72 ret = -ENOMEM;
73 }
74 mutex_unlock(&scsi_sense_cache_mutex);
75 return ret;
76}
77
78static void
79scsi_set_blocked(struct scsi_cmnd *cmd, int reason)
80{
81 struct Scsi_Host *host = cmd->device->host;
82 struct scsi_device *device = cmd->device;
83 struct scsi_target *starget = scsi_target(device);
84
85 /*
86 * Set the appropriate busy bit for the device/host.
87 *
88 * If the host/device isn't busy, assume that something actually
89 * completed, and that we should be able to queue a command now.
90 *
91 * Note that the prior mid-layer assumption that any host could
92 * always queue at least one command is now broken. The mid-layer
93 * will implement a user specifiable stall (see
94 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
95 * if a command is requeued with no other commands outstanding
96 * either for the device or for the host.
97 */
98 switch (reason) {
99 case SCSI_MLQUEUE_HOST_BUSY:
100 atomic_set(&host->host_blocked, host->max_host_blocked);
101 break;
102 case SCSI_MLQUEUE_DEVICE_BUSY:
103 case SCSI_MLQUEUE_EH_RETRY:
104 atomic_set(&device->device_blocked,
105 device->max_device_blocked);
106 break;
107 case SCSI_MLQUEUE_TARGET_BUSY:
108 atomic_set(&starget->target_blocked,
109 starget->max_target_blocked);
110 break;
111 }
112}
113
114static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd, unsigned long msecs)
115{
116 struct request *rq = scsi_cmd_to_rq(cmd);
117
118 if (rq->rq_flags & RQF_DONTPREP) {
119 rq->rq_flags &= ~RQF_DONTPREP;
120 scsi_mq_uninit_cmd(cmd);
121 } else {
122 WARN_ON_ONCE(true);
123 }
124
125 blk_mq_requeue_request(rq, false);
126 if (!scsi_host_in_recovery(cmd->device->host))
127 blk_mq_delay_kick_requeue_list(rq->q, msecs);
128}
129
130/**
131 * __scsi_queue_insert - private queue insertion
132 * @cmd: The SCSI command being requeued
133 * @reason: The reason for the requeue
134 * @unbusy: Whether the queue should be unbusied
135 *
136 * This is a private queue insertion. The public interface
137 * scsi_queue_insert() always assumes the queue should be unbusied
138 * because it's always called before the completion. This function is
139 * for a requeue after completion, which should only occur in this
140 * file.
141 */
142static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy)
143{
144 struct scsi_device *device = cmd->device;
145
146 SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd,
147 "Inserting command %p into mlqueue\n", cmd));
148
149 scsi_set_blocked(cmd, reason);
150
151 /*
152 * Decrement the counters, since these commands are no longer
153 * active on the host/device.
154 */
155 if (unbusy)
156 scsi_device_unbusy(device, cmd);
157
158 /*
159 * Requeue this command. It will go before all other commands
160 * that are already in the queue. Schedule requeue work under
161 * lock such that the kblockd_schedule_work() call happens
162 * before blk_mq_destroy_queue() finishes.
163 */
164 cmd->result = 0;
165
166 blk_mq_requeue_request(scsi_cmd_to_rq(cmd),
167 !scsi_host_in_recovery(cmd->device->host));
168}
169
170/**
171 * scsi_queue_insert - Reinsert a command in the queue.
172 * @cmd: command that we are adding to queue.
173 * @reason: why we are inserting command to queue.
174 *
175 * We do this for one of two cases. Either the host is busy and it cannot accept
176 * any more commands for the time being, or the device returned QUEUE_FULL and
177 * can accept no more commands.
178 *
179 * Context: This could be called either from an interrupt context or a normal
180 * process context.
181 */
182void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
183{
184 __scsi_queue_insert(cmd, reason, true);
185}
186
187void scsi_failures_reset_retries(struct scsi_failures *failures)
188{
189 struct scsi_failure *failure;
190
191 failures->total_retries = 0;
192
193 for (failure = failures->failure_definitions; failure->result;
194 failure++)
195 failure->retries = 0;
196}
197EXPORT_SYMBOL_GPL(scsi_failures_reset_retries);
198
199/**
200 * scsi_check_passthrough - Determine if passthrough scsi_cmnd needs a retry.
201 * @scmd: scsi_cmnd to check.
202 * @failures: scsi_failures struct that lists failures to check for.
203 *
204 * Returns -EAGAIN if the caller should retry else 0.
205 */
206static int scsi_check_passthrough(struct scsi_cmnd *scmd,
207 struct scsi_failures *failures)
208{
209 struct scsi_failure *failure;
210 struct scsi_sense_hdr sshdr;
211 enum sam_status status;
212
213 if (!failures)
214 return 0;
215
216 for (failure = failures->failure_definitions; failure->result;
217 failure++) {
218 if (failure->result == SCMD_FAILURE_RESULT_ANY)
219 goto maybe_retry;
220
221 if (host_byte(scmd->result) &&
222 host_byte(scmd->result) == host_byte(failure->result))
223 goto maybe_retry;
224
225 status = status_byte(scmd->result);
226 if (!status)
227 continue;
228
229 if (failure->result == SCMD_FAILURE_STAT_ANY &&
230 !scsi_status_is_good(scmd->result))
231 goto maybe_retry;
232
233 if (status != status_byte(failure->result))
234 continue;
235
236 if (status_byte(failure->result) != SAM_STAT_CHECK_CONDITION ||
237 failure->sense == SCMD_FAILURE_SENSE_ANY)
238 goto maybe_retry;
239
240 if (!scsi_command_normalize_sense(scmd, &sshdr))
241 return 0;
242
243 if (failure->sense != sshdr.sense_key)
244 continue;
245
246 if (failure->asc == SCMD_FAILURE_ASC_ANY)
247 goto maybe_retry;
248
249 if (failure->asc != sshdr.asc)
250 continue;
251
252 if (failure->ascq == SCMD_FAILURE_ASCQ_ANY ||
253 failure->ascq == sshdr.ascq)
254 goto maybe_retry;
255 }
256
257 return 0;
258
259maybe_retry:
260 if (failure->allowed) {
261 if (failure->allowed == SCMD_FAILURE_NO_LIMIT ||
262 ++failure->retries <= failure->allowed)
263 return -EAGAIN;
264 } else {
265 if (failures->total_allowed == SCMD_FAILURE_NO_LIMIT ||
266 ++failures->total_retries <= failures->total_allowed)
267 return -EAGAIN;
268 }
269
270 return 0;
271}
272
273/**
274 * scsi_execute_cmd - insert request and wait for the result
275 * @sdev: scsi_device
276 * @cmd: scsi command
277 * @opf: block layer request cmd_flags
278 * @buffer: data buffer
279 * @bufflen: len of buffer
280 * @timeout: request timeout in HZ
281 * @ml_retries: number of times SCSI midlayer will retry request
282 * @args: Optional args. See struct definition for field descriptions
283 *
284 * Returns the scsi_cmnd result field if a command was executed, or a negative
285 * Linux error code if we didn't get that far.
286 */
287int scsi_execute_cmd(struct scsi_device *sdev, const unsigned char *cmd,
288 blk_opf_t opf, void *buffer, unsigned int bufflen,
289 int timeout, int ml_retries,
290 const struct scsi_exec_args *args)
291{
292 static const struct scsi_exec_args default_args;
293 struct request *req;
294 struct scsi_cmnd *scmd;
295 int ret;
296
297 if (!args)
298 args = &default_args;
299 else if (WARN_ON_ONCE(args->sense &&
300 args->sense_len != SCSI_SENSE_BUFFERSIZE))
301 return -EINVAL;
302
303retry:
304 req = scsi_alloc_request(sdev->request_queue, opf, args->req_flags);
305 if (IS_ERR(req))
306 return PTR_ERR(req);
307
308 if (bufflen) {
309 ret = blk_rq_map_kern(sdev->request_queue, req,
310 buffer, bufflen, GFP_NOIO);
311 if (ret)
312 goto out;
313 }
314 scmd = blk_mq_rq_to_pdu(req);
315 scmd->cmd_len = COMMAND_SIZE(cmd[0]);
316 memcpy(scmd->cmnd, cmd, scmd->cmd_len);
317 scmd->allowed = ml_retries;
318 scmd->flags |= args->scmd_flags;
319 req->timeout = timeout;
320 req->rq_flags |= RQF_QUIET;
321
322 /*
323 * head injection *required* here otherwise quiesce won't work
324 */
325 blk_execute_rq(req, true);
326
327 if (scsi_check_passthrough(scmd, args->failures) == -EAGAIN) {
328 blk_mq_free_request(req);
329 goto retry;
330 }
331
332 /*
333 * Some devices (USB mass-storage in particular) may transfer
334 * garbage data together with a residue indicating that the data
335 * is invalid. Prevent the garbage from being misinterpreted
336 * and prevent security leaks by zeroing out the excess data.
337 */
338 if (unlikely(scmd->resid_len > 0 && scmd->resid_len <= bufflen))
339 memset(buffer + bufflen - scmd->resid_len, 0, scmd->resid_len);
340
341 if (args->resid)
342 *args->resid = scmd->resid_len;
343 if (args->sense)
344 memcpy(args->sense, scmd->sense_buffer, SCSI_SENSE_BUFFERSIZE);
345 if (args->sshdr)
346 scsi_normalize_sense(scmd->sense_buffer, scmd->sense_len,
347 args->sshdr);
348
349 ret = scmd->result;
350 out:
351 blk_mq_free_request(req);
352
353 return ret;
354}
355EXPORT_SYMBOL(scsi_execute_cmd);
356
357/*
358 * Wake up the error handler if necessary. Avoid as follows that the error
359 * handler is not woken up if host in-flight requests number ==
360 * shost->host_failed: use call_rcu() in scsi_eh_scmd_add() in combination
361 * with an RCU read lock in this function to ensure that this function in
362 * its entirety either finishes before scsi_eh_scmd_add() increases the
363 * host_failed counter or that it notices the shost state change made by
364 * scsi_eh_scmd_add().
365 */
366static void scsi_dec_host_busy(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
367{
368 unsigned long flags;
369
370 rcu_read_lock();
371 __clear_bit(SCMD_STATE_INFLIGHT, &cmd->state);
372 if (unlikely(scsi_host_in_recovery(shost))) {
373 unsigned int busy = scsi_host_busy(shost);
374
375 spin_lock_irqsave(shost->host_lock, flags);
376 if (shost->host_failed || shost->host_eh_scheduled)
377 scsi_eh_wakeup(shost, busy);
378 spin_unlock_irqrestore(shost->host_lock, flags);
379 }
380 rcu_read_unlock();
381}
382
383void scsi_device_unbusy(struct scsi_device *sdev, struct scsi_cmnd *cmd)
384{
385 struct Scsi_Host *shost = sdev->host;
386 struct scsi_target *starget = scsi_target(sdev);
387
388 scsi_dec_host_busy(shost, cmd);
389
390 if (starget->can_queue > 0)
391 atomic_dec(&starget->target_busy);
392
393 sbitmap_put(&sdev->budget_map, cmd->budget_token);
394 cmd->budget_token = -1;
395}
396
397/*
398 * Kick the queue of SCSI device @sdev if @sdev != current_sdev. Called with
399 * interrupts disabled.
400 */
401static void scsi_kick_sdev_queue(struct scsi_device *sdev, void *data)
402{
403 struct scsi_device *current_sdev = data;
404
405 if (sdev != current_sdev)
406 blk_mq_run_hw_queues(sdev->request_queue, true);
407}
408
409/*
410 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
411 * and call blk_run_queue for all the scsi_devices on the target -
412 * including current_sdev first.
413 *
414 * Called with *no* scsi locks held.
415 */
416static void scsi_single_lun_run(struct scsi_device *current_sdev)
417{
418 struct Scsi_Host *shost = current_sdev->host;
419 struct scsi_target *starget = scsi_target(current_sdev);
420 unsigned long flags;
421
422 spin_lock_irqsave(shost->host_lock, flags);
423 starget->starget_sdev_user = NULL;
424 spin_unlock_irqrestore(shost->host_lock, flags);
425
426 /*
427 * Call blk_run_queue for all LUNs on the target, starting with
428 * current_sdev. We race with others (to set starget_sdev_user),
429 * but in most cases, we will be first. Ideally, each LU on the
430 * target would get some limited time or requests on the target.
431 */
432 blk_mq_run_hw_queues(current_sdev->request_queue,
433 shost->queuecommand_may_block);
434
435 spin_lock_irqsave(shost->host_lock, flags);
436 if (!starget->starget_sdev_user)
437 __starget_for_each_device(starget, current_sdev,
438 scsi_kick_sdev_queue);
439 spin_unlock_irqrestore(shost->host_lock, flags);
440}
441
442static inline bool scsi_device_is_busy(struct scsi_device *sdev)
443{
444 if (scsi_device_busy(sdev) >= sdev->queue_depth)
445 return true;
446 if (atomic_read(&sdev->device_blocked) > 0)
447 return true;
448 return false;
449}
450
451static inline bool scsi_target_is_busy(struct scsi_target *starget)
452{
453 if (starget->can_queue > 0) {
454 if (atomic_read(&starget->target_busy) >= starget->can_queue)
455 return true;
456 if (atomic_read(&starget->target_blocked) > 0)
457 return true;
458 }
459 return false;
460}
461
462static inline bool scsi_host_is_busy(struct Scsi_Host *shost)
463{
464 if (atomic_read(&shost->host_blocked) > 0)
465 return true;
466 if (shost->host_self_blocked)
467 return true;
468 return false;
469}
470
471static void scsi_starved_list_run(struct Scsi_Host *shost)
472{
473 LIST_HEAD(starved_list);
474 struct scsi_device *sdev;
475 unsigned long flags;
476
477 spin_lock_irqsave(shost->host_lock, flags);
478 list_splice_init(&shost->starved_list, &starved_list);
479
480 while (!list_empty(&starved_list)) {
481 struct request_queue *slq;
482
483 /*
484 * As long as shost is accepting commands and we have
485 * starved queues, call blk_run_queue. scsi_request_fn
486 * drops the queue_lock and can add us back to the
487 * starved_list.
488 *
489 * host_lock protects the starved_list and starved_entry.
490 * scsi_request_fn must get the host_lock before checking
491 * or modifying starved_list or starved_entry.
492 */
493 if (scsi_host_is_busy(shost))
494 break;
495
496 sdev = list_entry(starved_list.next,
497 struct scsi_device, starved_entry);
498 list_del_init(&sdev->starved_entry);
499 if (scsi_target_is_busy(scsi_target(sdev))) {
500 list_move_tail(&sdev->starved_entry,
501 &shost->starved_list);
502 continue;
503 }
504
505 /*
506 * Once we drop the host lock, a racing scsi_remove_device()
507 * call may remove the sdev from the starved list and destroy
508 * it and the queue. Mitigate by taking a reference to the
509 * queue and never touching the sdev again after we drop the
510 * host lock. Note: if __scsi_remove_device() invokes
511 * blk_mq_destroy_queue() before the queue is run from this
512 * function then blk_run_queue() will return immediately since
513 * blk_mq_destroy_queue() marks the queue with QUEUE_FLAG_DYING.
514 */
515 slq = sdev->request_queue;
516 if (!blk_get_queue(slq))
517 continue;
518 spin_unlock_irqrestore(shost->host_lock, flags);
519
520 blk_mq_run_hw_queues(slq, false);
521 blk_put_queue(slq);
522
523 spin_lock_irqsave(shost->host_lock, flags);
524 }
525 /* put any unprocessed entries back */
526 list_splice(&starved_list, &shost->starved_list);
527 spin_unlock_irqrestore(shost->host_lock, flags);
528}
529
530/**
531 * scsi_run_queue - Select a proper request queue to serve next.
532 * @q: last request's queue
533 *
534 * The previous command was completely finished, start a new one if possible.
535 */
536static void scsi_run_queue(struct request_queue *q)
537{
538 struct scsi_device *sdev = q->queuedata;
539
540 if (scsi_target(sdev)->single_lun)
541 scsi_single_lun_run(sdev);
542 if (!list_empty(&sdev->host->starved_list))
543 scsi_starved_list_run(sdev->host);
544
545 /* Note: blk_mq_kick_requeue_list() runs the queue asynchronously. */
546 blk_mq_kick_requeue_list(q);
547}
548
549void scsi_requeue_run_queue(struct work_struct *work)
550{
551 struct scsi_device *sdev;
552 struct request_queue *q;
553
554 sdev = container_of(work, struct scsi_device, requeue_work);
555 q = sdev->request_queue;
556 scsi_run_queue(q);
557}
558
559void scsi_run_host_queues(struct Scsi_Host *shost)
560{
561 struct scsi_device *sdev;
562
563 shost_for_each_device(sdev, shost)
564 scsi_run_queue(sdev->request_queue);
565}
566
567static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
568{
569 if (!blk_rq_is_passthrough(scsi_cmd_to_rq(cmd))) {
570 struct scsi_driver *drv = scsi_cmd_to_driver(cmd);
571
572 if (drv->uninit_command)
573 drv->uninit_command(cmd);
574 }
575}
576
577void scsi_free_sgtables(struct scsi_cmnd *cmd)
578{
579 if (cmd->sdb.table.nents)
580 sg_free_table_chained(&cmd->sdb.table,
581 SCSI_INLINE_SG_CNT);
582 if (scsi_prot_sg_count(cmd))
583 sg_free_table_chained(&cmd->prot_sdb->table,
584 SCSI_INLINE_PROT_SG_CNT);
585}
586EXPORT_SYMBOL_GPL(scsi_free_sgtables);
587
588static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
589{
590 scsi_free_sgtables(cmd);
591 scsi_uninit_cmd(cmd);
592}
593
594static void scsi_run_queue_async(struct scsi_device *sdev)
595{
596 if (scsi_host_in_recovery(sdev->host))
597 return;
598
599 if (scsi_target(sdev)->single_lun ||
600 !list_empty(&sdev->host->starved_list)) {
601 kblockd_schedule_work(&sdev->requeue_work);
602 } else {
603 /*
604 * smp_mb() present in sbitmap_queue_clear() or implied in
605 * .end_io is for ordering writing .device_busy in
606 * scsi_device_unbusy() and reading sdev->restarts.
607 */
608 int old = atomic_read(&sdev->restarts);
609
610 /*
611 * ->restarts has to be kept as non-zero if new budget
612 * contention occurs.
613 *
614 * No need to run queue when either another re-run
615 * queue wins in updating ->restarts or a new budget
616 * contention occurs.
617 */
618 if (old && atomic_cmpxchg(&sdev->restarts, old, 0) == old)
619 blk_mq_run_hw_queues(sdev->request_queue, true);
620 }
621}
622
623/* Returns false when no more bytes to process, true if there are more */
624static bool scsi_end_request(struct request *req, blk_status_t error,
625 unsigned int bytes)
626{
627 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
628 struct scsi_device *sdev = cmd->device;
629 struct request_queue *q = sdev->request_queue;
630
631 if (blk_update_request(req, error, bytes))
632 return true;
633
634 // XXX:
635 if (blk_queue_add_random(q))
636 add_disk_randomness(req->q->disk);
637
638 WARN_ON_ONCE(!blk_rq_is_passthrough(req) &&
639 !(cmd->flags & SCMD_INITIALIZED));
640 cmd->flags = 0;
641
642 /*
643 * Calling rcu_barrier() is not necessary here because the
644 * SCSI error handler guarantees that the function called by
645 * call_rcu() has been called before scsi_end_request() is
646 * called.
647 */
648 destroy_rcu_head(&cmd->rcu);
649
650 /*
651 * In the MQ case the command gets freed by __blk_mq_end_request,
652 * so we have to do all cleanup that depends on it earlier.
653 *
654 * We also can't kick the queues from irq context, so we
655 * will have to defer it to a workqueue.
656 */
657 scsi_mq_uninit_cmd(cmd);
658
659 /*
660 * queue is still alive, so grab the ref for preventing it
661 * from being cleaned up during running queue.
662 */
663 percpu_ref_get(&q->q_usage_counter);
664
665 __blk_mq_end_request(req, error);
666
667 scsi_run_queue_async(sdev);
668
669 percpu_ref_put(&q->q_usage_counter);
670 return false;
671}
672
673/**
674 * scsi_result_to_blk_status - translate a SCSI result code into blk_status_t
675 * @result: scsi error code
676 *
677 * Translate a SCSI result code into a blk_status_t value.
678 */
679static blk_status_t scsi_result_to_blk_status(int result)
680{
681 /*
682 * Check the scsi-ml byte first in case we converted a host or status
683 * byte.
684 */
685 switch (scsi_ml_byte(result)) {
686 case SCSIML_STAT_OK:
687 break;
688 case SCSIML_STAT_RESV_CONFLICT:
689 return BLK_STS_RESV_CONFLICT;
690 case SCSIML_STAT_NOSPC:
691 return BLK_STS_NOSPC;
692 case SCSIML_STAT_MED_ERROR:
693 return BLK_STS_MEDIUM;
694 case SCSIML_STAT_TGT_FAILURE:
695 return BLK_STS_TARGET;
696 case SCSIML_STAT_DL_TIMEOUT:
697 return BLK_STS_DURATION_LIMIT;
698 }
699
700 switch (host_byte(result)) {
701 case DID_OK:
702 if (scsi_status_is_good(result))
703 return BLK_STS_OK;
704 return BLK_STS_IOERR;
705 case DID_TRANSPORT_FAILFAST:
706 case DID_TRANSPORT_MARGINAL:
707 return BLK_STS_TRANSPORT;
708 default:
709 return BLK_STS_IOERR;
710 }
711}
712
713/**
714 * scsi_rq_err_bytes - determine number of bytes till the next failure boundary
715 * @rq: request to examine
716 *
717 * Description:
718 * A request could be merge of IOs which require different failure
719 * handling. This function determines the number of bytes which
720 * can be failed from the beginning of the request without
721 * crossing into area which need to be retried further.
722 *
723 * Return:
724 * The number of bytes to fail.
725 */
726static unsigned int scsi_rq_err_bytes(const struct request *rq)
727{
728 blk_opf_t ff = rq->cmd_flags & REQ_FAILFAST_MASK;
729 unsigned int bytes = 0;
730 struct bio *bio;
731
732 if (!(rq->rq_flags & RQF_MIXED_MERGE))
733 return blk_rq_bytes(rq);
734
735 /*
736 * Currently the only 'mixing' which can happen is between
737 * different fastfail types. We can safely fail portions
738 * which have all the failfast bits that the first one has -
739 * the ones which are at least as eager to fail as the first
740 * one.
741 */
742 for (bio = rq->bio; bio; bio = bio->bi_next) {
743 if ((bio->bi_opf & ff) != ff)
744 break;
745 bytes += bio->bi_iter.bi_size;
746 }
747
748 /* this could lead to infinite loop */
749 BUG_ON(blk_rq_bytes(rq) && !bytes);
750 return bytes;
751}
752
753static bool scsi_cmd_runtime_exceeced(struct scsi_cmnd *cmd)
754{
755 struct request *req = scsi_cmd_to_rq(cmd);
756 unsigned long wait_for;
757
758 if (cmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT)
759 return false;
760
761 wait_for = (cmd->allowed + 1) * req->timeout;
762 if (time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
763 scmd_printk(KERN_ERR, cmd, "timing out command, waited %lus\n",
764 wait_for/HZ);
765 return true;
766 }
767 return false;
768}
769
770/*
771 * When ALUA transition state is returned, reprep the cmd to
772 * use the ALUA handler's transition timeout. Delay the reprep
773 * 1 sec to avoid aggressive retries of the target in that
774 * state.
775 */
776#define ALUA_TRANSITION_REPREP_DELAY 1000
777
778/* Helper for scsi_io_completion() when special action required. */
779static void scsi_io_completion_action(struct scsi_cmnd *cmd, int result)
780{
781 struct request *req = scsi_cmd_to_rq(cmd);
782 int level = 0;
783 enum {ACTION_FAIL, ACTION_REPREP, ACTION_DELAYED_REPREP,
784 ACTION_RETRY, ACTION_DELAYED_RETRY} action;
785 struct scsi_sense_hdr sshdr;
786 bool sense_valid;
787 bool sense_current = true; /* false implies "deferred sense" */
788 blk_status_t blk_stat;
789
790 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
791 if (sense_valid)
792 sense_current = !scsi_sense_is_deferred(&sshdr);
793
794 blk_stat = scsi_result_to_blk_status(result);
795
796 if (host_byte(result) == DID_RESET) {
797 /* Third party bus reset or reset for error recovery
798 * reasons. Just retry the command and see what
799 * happens.
800 */
801 action = ACTION_RETRY;
802 } else if (sense_valid && sense_current) {
803 switch (sshdr.sense_key) {
804 case UNIT_ATTENTION:
805 if (cmd->device->removable) {
806 /* Detected disc change. Set a bit
807 * and quietly refuse further access.
808 */
809 cmd->device->changed = 1;
810 action = ACTION_FAIL;
811 } else {
812 /* Must have been a power glitch, or a
813 * bus reset. Could not have been a
814 * media change, so we just retry the
815 * command and see what happens.
816 */
817 action = ACTION_RETRY;
818 }
819 break;
820 case ILLEGAL_REQUEST:
821 /* If we had an ILLEGAL REQUEST returned, then
822 * we may have performed an unsupported
823 * command. The only thing this should be
824 * would be a ten byte read where only a six
825 * byte read was supported. Also, on a system
826 * where READ CAPACITY failed, we may have
827 * read past the end of the disk.
828 */
829 if ((cmd->device->use_10_for_rw &&
830 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
831 (cmd->cmnd[0] == READ_10 ||
832 cmd->cmnd[0] == WRITE_10)) {
833 /* This will issue a new 6-byte command. */
834 cmd->device->use_10_for_rw = 0;
835 action = ACTION_REPREP;
836 } else if (sshdr.asc == 0x10) /* DIX */ {
837 action = ACTION_FAIL;
838 blk_stat = BLK_STS_PROTECTION;
839 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
840 } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
841 action = ACTION_FAIL;
842 blk_stat = BLK_STS_TARGET;
843 } else
844 action = ACTION_FAIL;
845 break;
846 case ABORTED_COMMAND:
847 action = ACTION_FAIL;
848 if (sshdr.asc == 0x10) /* DIF */
849 blk_stat = BLK_STS_PROTECTION;
850 break;
851 case NOT_READY:
852 /* If the device is in the process of becoming
853 * ready, or has a temporary blockage, retry.
854 */
855 if (sshdr.asc == 0x04) {
856 switch (sshdr.ascq) {
857 case 0x01: /* becoming ready */
858 case 0x04: /* format in progress */
859 case 0x05: /* rebuild in progress */
860 case 0x06: /* recalculation in progress */
861 case 0x07: /* operation in progress */
862 case 0x08: /* Long write in progress */
863 case 0x09: /* self test in progress */
864 case 0x11: /* notify (enable spinup) required */
865 case 0x14: /* space allocation in progress */
866 case 0x1a: /* start stop unit in progress */
867 case 0x1b: /* sanitize in progress */
868 case 0x1d: /* configuration in progress */
869 case 0x24: /* depopulation in progress */
870 case 0x25: /* depopulation restore in progress */
871 action = ACTION_DELAYED_RETRY;
872 break;
873 case 0x0a: /* ALUA state transition */
874 action = ACTION_DELAYED_REPREP;
875 break;
876 default:
877 action = ACTION_FAIL;
878 break;
879 }
880 } else
881 action = ACTION_FAIL;
882 break;
883 case VOLUME_OVERFLOW:
884 /* See SSC3rXX or current. */
885 action = ACTION_FAIL;
886 break;
887 case DATA_PROTECT:
888 action = ACTION_FAIL;
889 if ((sshdr.asc == 0x0C && sshdr.ascq == 0x12) ||
890 (sshdr.asc == 0x55 &&
891 (sshdr.ascq == 0x0E || sshdr.ascq == 0x0F))) {
892 /* Insufficient zone resources */
893 blk_stat = BLK_STS_ZONE_OPEN_RESOURCE;
894 }
895 break;
896 case COMPLETED:
897 fallthrough;
898 default:
899 action = ACTION_FAIL;
900 break;
901 }
902 } else
903 action = ACTION_FAIL;
904
905 if (action != ACTION_FAIL && scsi_cmd_runtime_exceeced(cmd))
906 action = ACTION_FAIL;
907
908 switch (action) {
909 case ACTION_FAIL:
910 /* Give up and fail the remainder of the request */
911 if (!(req->rq_flags & RQF_QUIET)) {
912 static DEFINE_RATELIMIT_STATE(_rs,
913 DEFAULT_RATELIMIT_INTERVAL,
914 DEFAULT_RATELIMIT_BURST);
915
916 if (unlikely(scsi_logging_level))
917 level =
918 SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
919 SCSI_LOG_MLCOMPLETE_BITS);
920
921 /*
922 * if logging is enabled the failure will be printed
923 * in scsi_log_completion(), so avoid duplicate messages
924 */
925 if (!level && __ratelimit(&_rs)) {
926 scsi_print_result(cmd, NULL, FAILED);
927 if (sense_valid)
928 scsi_print_sense(cmd);
929 scsi_print_command(cmd);
930 }
931 }
932 if (!scsi_end_request(req, blk_stat, scsi_rq_err_bytes(req)))
933 return;
934 fallthrough;
935 case ACTION_REPREP:
936 scsi_mq_requeue_cmd(cmd, 0);
937 break;
938 case ACTION_DELAYED_REPREP:
939 scsi_mq_requeue_cmd(cmd, ALUA_TRANSITION_REPREP_DELAY);
940 break;
941 case ACTION_RETRY:
942 /* Retry the same command immediately */
943 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, false);
944 break;
945 case ACTION_DELAYED_RETRY:
946 /* Retry the same command after a delay */
947 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, false);
948 break;
949 }
950}
951
952/*
953 * Helper for scsi_io_completion() when cmd->result is non-zero. Returns a
954 * new result that may suppress further error checking. Also modifies
955 * *blk_statp in some cases.
956 */
957static int scsi_io_completion_nz_result(struct scsi_cmnd *cmd, int result,
958 blk_status_t *blk_statp)
959{
960 bool sense_valid;
961 bool sense_current = true; /* false implies "deferred sense" */
962 struct request *req = scsi_cmd_to_rq(cmd);
963 struct scsi_sense_hdr sshdr;
964
965 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
966 if (sense_valid)
967 sense_current = !scsi_sense_is_deferred(&sshdr);
968
969 if (blk_rq_is_passthrough(req)) {
970 if (sense_valid) {
971 /*
972 * SG_IO wants current and deferred errors
973 */
974 cmd->sense_len = min(8 + cmd->sense_buffer[7],
975 SCSI_SENSE_BUFFERSIZE);
976 }
977 if (sense_current)
978 *blk_statp = scsi_result_to_blk_status(result);
979 } else if (blk_rq_bytes(req) == 0 && sense_current) {
980 /*
981 * Flush commands do not transfers any data, and thus cannot use
982 * good_bytes != blk_rq_bytes(req) as the signal for an error.
983 * This sets *blk_statp explicitly for the problem case.
984 */
985 *blk_statp = scsi_result_to_blk_status(result);
986 }
987 /*
988 * Recovered errors need reporting, but they're always treated as
989 * success, so fiddle the result code here. For passthrough requests
990 * we already took a copy of the original into sreq->result which
991 * is what gets returned to the user
992 */
993 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
994 bool do_print = true;
995 /*
996 * if ATA PASS-THROUGH INFORMATION AVAILABLE [0x0, 0x1d]
997 * skip print since caller wants ATA registers. Only occurs
998 * on SCSI ATA PASS_THROUGH commands when CK_COND=1
999 */
1000 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
1001 do_print = false;
1002 else if (req->rq_flags & RQF_QUIET)
1003 do_print = false;
1004 if (do_print)
1005 scsi_print_sense(cmd);
1006 result = 0;
1007 /* for passthrough, *blk_statp may be set */
1008 *blk_statp = BLK_STS_OK;
1009 }
1010 /*
1011 * Another corner case: the SCSI status byte is non-zero but 'good'.
1012 * Example: PRE-FETCH command returns SAM_STAT_CONDITION_MET when
1013 * it is able to fit nominated LBs in its cache (and SAM_STAT_GOOD
1014 * if it can't fit). Treat SAM_STAT_CONDITION_MET and the related
1015 * intermediate statuses (both obsolete in SAM-4) as good.
1016 */
1017 if ((result & 0xff) && scsi_status_is_good(result)) {
1018 result = 0;
1019 *blk_statp = BLK_STS_OK;
1020 }
1021 return result;
1022}
1023
1024/**
1025 * scsi_io_completion - Completion processing for SCSI commands.
1026 * @cmd: command that is finished.
1027 * @good_bytes: number of processed bytes.
1028 *
1029 * We will finish off the specified number of sectors. If we are done, the
1030 * command block will be released and the queue function will be goosed. If we
1031 * are not done then we have to figure out what to do next:
1032 *
1033 * a) We can call scsi_mq_requeue_cmd(). The request will be
1034 * unprepared and put back on the queue. Then a new command will
1035 * be created for it. This should be used if we made forward
1036 * progress, or if we want to switch from READ(10) to READ(6) for
1037 * example.
1038 *
1039 * b) We can call scsi_io_completion_action(). The request will be
1040 * put back on the queue and retried using the same command as
1041 * before, possibly after a delay.
1042 *
1043 * c) We can call scsi_end_request() with blk_stat other than
1044 * BLK_STS_OK, to fail the remainder of the request.
1045 */
1046void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
1047{
1048 int result = cmd->result;
1049 struct request *req = scsi_cmd_to_rq(cmd);
1050 blk_status_t blk_stat = BLK_STS_OK;
1051
1052 if (unlikely(result)) /* a nz result may or may not be an error */
1053 result = scsi_io_completion_nz_result(cmd, result, &blk_stat);
1054
1055 /*
1056 * Next deal with any sectors which we were able to correctly
1057 * handle.
1058 */
1059 SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd,
1060 "%u sectors total, %d bytes done.\n",
1061 blk_rq_sectors(req), good_bytes));
1062
1063 /*
1064 * Failed, zero length commands always need to drop down
1065 * to retry code. Fast path should return in this block.
1066 */
1067 if (likely(blk_rq_bytes(req) > 0 || blk_stat == BLK_STS_OK)) {
1068 if (likely(!scsi_end_request(req, blk_stat, good_bytes)))
1069 return; /* no bytes remaining */
1070 }
1071
1072 /* Kill remainder if no retries. */
1073 if (unlikely(blk_stat && scsi_noretry_cmd(cmd))) {
1074 if (scsi_end_request(req, blk_stat, blk_rq_bytes(req)))
1075 WARN_ONCE(true,
1076 "Bytes remaining after failed, no-retry command");
1077 return;
1078 }
1079
1080 /*
1081 * If there had been no error, but we have leftover bytes in the
1082 * request just queue the command up again.
1083 */
1084 if (likely(result == 0))
1085 scsi_mq_requeue_cmd(cmd, 0);
1086 else
1087 scsi_io_completion_action(cmd, result);
1088}
1089
1090static inline bool scsi_cmd_needs_dma_drain(struct scsi_device *sdev,
1091 struct request *rq)
1092{
1093 return sdev->dma_drain_len && blk_rq_is_passthrough(rq) &&
1094 !op_is_write(req_op(rq)) &&
1095 sdev->host->hostt->dma_need_drain(rq);
1096}
1097
1098/**
1099 * scsi_alloc_sgtables - Allocate and initialize data and integrity scatterlists
1100 * @cmd: SCSI command data structure to initialize.
1101 *
1102 * Initializes @cmd->sdb and also @cmd->prot_sdb if data integrity is enabled
1103 * for @cmd.
1104 *
1105 * Returns:
1106 * * BLK_STS_OK - on success
1107 * * BLK_STS_RESOURCE - if the failure is retryable
1108 * * BLK_STS_IOERR - if the failure is fatal
1109 */
1110blk_status_t scsi_alloc_sgtables(struct scsi_cmnd *cmd)
1111{
1112 struct scsi_device *sdev = cmd->device;
1113 struct request *rq = scsi_cmd_to_rq(cmd);
1114 unsigned short nr_segs = blk_rq_nr_phys_segments(rq);
1115 struct scatterlist *last_sg = NULL;
1116 blk_status_t ret;
1117 bool need_drain = scsi_cmd_needs_dma_drain(sdev, rq);
1118 int count;
1119
1120 if (WARN_ON_ONCE(!nr_segs))
1121 return BLK_STS_IOERR;
1122
1123 /*
1124 * Make sure there is space for the drain. The driver must adjust
1125 * max_hw_segments to be prepared for this.
1126 */
1127 if (need_drain)
1128 nr_segs++;
1129
1130 /*
1131 * If sg table allocation fails, requeue request later.
1132 */
1133 if (unlikely(sg_alloc_table_chained(&cmd->sdb.table, nr_segs,
1134 cmd->sdb.table.sgl, SCSI_INLINE_SG_CNT)))
1135 return BLK_STS_RESOURCE;
1136
1137 /*
1138 * Next, walk the list, and fill in the addresses and sizes of
1139 * each segment.
1140 */
1141 count = __blk_rq_map_sg(rq->q, rq, cmd->sdb.table.sgl, &last_sg);
1142
1143 if (blk_rq_bytes(rq) & rq->q->dma_pad_mask) {
1144 unsigned int pad_len =
1145 (rq->q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1;
1146
1147 last_sg->length += pad_len;
1148 cmd->extra_len += pad_len;
1149 }
1150
1151 if (need_drain) {
1152 sg_unmark_end(last_sg);
1153 last_sg = sg_next(last_sg);
1154 sg_set_buf(last_sg, sdev->dma_drain_buf, sdev->dma_drain_len);
1155 sg_mark_end(last_sg);
1156
1157 cmd->extra_len += sdev->dma_drain_len;
1158 count++;
1159 }
1160
1161 BUG_ON(count > cmd->sdb.table.nents);
1162 cmd->sdb.table.nents = count;
1163 cmd->sdb.length = blk_rq_payload_bytes(rq);
1164
1165 if (blk_integrity_rq(rq)) {
1166 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1167 int ivecs;
1168
1169 if (WARN_ON_ONCE(!prot_sdb)) {
1170 /*
1171 * This can happen if someone (e.g. multipath)
1172 * queues a command to a device on an adapter
1173 * that does not support DIX.
1174 */
1175 ret = BLK_STS_IOERR;
1176 goto out_free_sgtables;
1177 }
1178
1179 ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
1180
1181 if (sg_alloc_table_chained(&prot_sdb->table, ivecs,
1182 prot_sdb->table.sgl,
1183 SCSI_INLINE_PROT_SG_CNT)) {
1184 ret = BLK_STS_RESOURCE;
1185 goto out_free_sgtables;
1186 }
1187
1188 count = blk_rq_map_integrity_sg(rq->q, rq->bio,
1189 prot_sdb->table.sgl);
1190 BUG_ON(count > ivecs);
1191 BUG_ON(count > queue_max_integrity_segments(rq->q));
1192
1193 cmd->prot_sdb = prot_sdb;
1194 cmd->prot_sdb->table.nents = count;
1195 }
1196
1197 return BLK_STS_OK;
1198out_free_sgtables:
1199 scsi_free_sgtables(cmd);
1200 return ret;
1201}
1202EXPORT_SYMBOL(scsi_alloc_sgtables);
1203
1204/**
1205 * scsi_initialize_rq - initialize struct scsi_cmnd partially
1206 * @rq: Request associated with the SCSI command to be initialized.
1207 *
1208 * This function initializes the members of struct scsi_cmnd that must be
1209 * initialized before request processing starts and that won't be
1210 * reinitialized if a SCSI command is requeued.
1211 */
1212static void scsi_initialize_rq(struct request *rq)
1213{
1214 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1215
1216 memset(cmd->cmnd, 0, sizeof(cmd->cmnd));
1217 cmd->cmd_len = MAX_COMMAND_SIZE;
1218 cmd->sense_len = 0;
1219 init_rcu_head(&cmd->rcu);
1220 cmd->jiffies_at_alloc = jiffies;
1221 cmd->retries = 0;
1222}
1223
1224struct request *scsi_alloc_request(struct request_queue *q, blk_opf_t opf,
1225 blk_mq_req_flags_t flags)
1226{
1227 struct request *rq;
1228
1229 rq = blk_mq_alloc_request(q, opf, flags);
1230 if (!IS_ERR(rq))
1231 scsi_initialize_rq(rq);
1232 return rq;
1233}
1234EXPORT_SYMBOL_GPL(scsi_alloc_request);
1235
1236/*
1237 * Only called when the request isn't completed by SCSI, and not freed by
1238 * SCSI
1239 */
1240static void scsi_cleanup_rq(struct request *rq)
1241{
1242 if (rq->rq_flags & RQF_DONTPREP) {
1243 scsi_mq_uninit_cmd(blk_mq_rq_to_pdu(rq));
1244 rq->rq_flags &= ~RQF_DONTPREP;
1245 }
1246}
1247
1248/* Called before a request is prepared. See also scsi_mq_prep_fn(). */
1249void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd)
1250{
1251 struct request *rq = scsi_cmd_to_rq(cmd);
1252
1253 if (!blk_rq_is_passthrough(rq) && !(cmd->flags & SCMD_INITIALIZED)) {
1254 cmd->flags |= SCMD_INITIALIZED;
1255 scsi_initialize_rq(rq);
1256 }
1257
1258 cmd->device = dev;
1259 INIT_LIST_HEAD(&cmd->eh_entry);
1260 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
1261}
1262
1263static blk_status_t scsi_setup_scsi_cmnd(struct scsi_device *sdev,
1264 struct request *req)
1265{
1266 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1267
1268 /*
1269 * Passthrough requests may transfer data, in which case they must
1270 * a bio attached to them. Or they might contain a SCSI command
1271 * that does not transfer data, in which case they may optionally
1272 * submit a request without an attached bio.
1273 */
1274 if (req->bio) {
1275 blk_status_t ret = scsi_alloc_sgtables(cmd);
1276 if (unlikely(ret != BLK_STS_OK))
1277 return ret;
1278 } else {
1279 BUG_ON(blk_rq_bytes(req));
1280
1281 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1282 }
1283
1284 cmd->transfersize = blk_rq_bytes(req);
1285 return BLK_STS_OK;
1286}
1287
1288static blk_status_t
1289scsi_device_state_check(struct scsi_device *sdev, struct request *req)
1290{
1291 switch (sdev->sdev_state) {
1292 case SDEV_CREATED:
1293 return BLK_STS_OK;
1294 case SDEV_OFFLINE:
1295 case SDEV_TRANSPORT_OFFLINE:
1296 /*
1297 * If the device is offline we refuse to process any
1298 * commands. The device must be brought online
1299 * before trying any recovery commands.
1300 */
1301 if (!sdev->offline_already) {
1302 sdev->offline_already = true;
1303 sdev_printk(KERN_ERR, sdev,
1304 "rejecting I/O to offline device\n");
1305 }
1306 return BLK_STS_IOERR;
1307 case SDEV_DEL:
1308 /*
1309 * If the device is fully deleted, we refuse to
1310 * process any commands as well.
1311 */
1312 sdev_printk(KERN_ERR, sdev,
1313 "rejecting I/O to dead device\n");
1314 return BLK_STS_IOERR;
1315 case SDEV_BLOCK:
1316 case SDEV_CREATED_BLOCK:
1317 return BLK_STS_RESOURCE;
1318 case SDEV_QUIESCE:
1319 /*
1320 * If the device is blocked we only accept power management
1321 * commands.
1322 */
1323 if (req && WARN_ON_ONCE(!(req->rq_flags & RQF_PM)))
1324 return BLK_STS_RESOURCE;
1325 return BLK_STS_OK;
1326 default:
1327 /*
1328 * For any other not fully online state we only allow
1329 * power management commands.
1330 */
1331 if (req && !(req->rq_flags & RQF_PM))
1332 return BLK_STS_OFFLINE;
1333 return BLK_STS_OK;
1334 }
1335}
1336
1337/*
1338 * scsi_dev_queue_ready: if we can send requests to sdev, assign one token
1339 * and return the token else return -1.
1340 */
1341static inline int scsi_dev_queue_ready(struct request_queue *q,
1342 struct scsi_device *sdev)
1343{
1344 int token;
1345
1346 token = sbitmap_get(&sdev->budget_map);
1347 if (token < 0)
1348 return -1;
1349
1350 if (!atomic_read(&sdev->device_blocked))
1351 return token;
1352
1353 /*
1354 * Only unblock if no other commands are pending and
1355 * if device_blocked has decreased to zero
1356 */
1357 if (scsi_device_busy(sdev) > 1 ||
1358 atomic_dec_return(&sdev->device_blocked) > 0) {
1359 sbitmap_put(&sdev->budget_map, token);
1360 return -1;
1361 }
1362
1363 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev,
1364 "unblocking device at zero depth\n"));
1365
1366 return token;
1367}
1368
1369/*
1370 * scsi_target_queue_ready: checks if there we can send commands to target
1371 * @sdev: scsi device on starget to check.
1372 */
1373static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1374 struct scsi_device *sdev)
1375{
1376 struct scsi_target *starget = scsi_target(sdev);
1377 unsigned int busy;
1378
1379 if (starget->single_lun) {
1380 spin_lock_irq(shost->host_lock);
1381 if (starget->starget_sdev_user &&
1382 starget->starget_sdev_user != sdev) {
1383 spin_unlock_irq(shost->host_lock);
1384 return 0;
1385 }
1386 starget->starget_sdev_user = sdev;
1387 spin_unlock_irq(shost->host_lock);
1388 }
1389
1390 if (starget->can_queue <= 0)
1391 return 1;
1392
1393 busy = atomic_inc_return(&starget->target_busy) - 1;
1394 if (atomic_read(&starget->target_blocked) > 0) {
1395 if (busy)
1396 goto starved;
1397
1398 /*
1399 * unblock after target_blocked iterates to zero
1400 */
1401 if (atomic_dec_return(&starget->target_blocked) > 0)
1402 goto out_dec;
1403
1404 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1405 "unblocking target at zero depth\n"));
1406 }
1407
1408 if (busy >= starget->can_queue)
1409 goto starved;
1410
1411 return 1;
1412
1413starved:
1414 spin_lock_irq(shost->host_lock);
1415 list_move_tail(&sdev->starved_entry, &shost->starved_list);
1416 spin_unlock_irq(shost->host_lock);
1417out_dec:
1418 if (starget->can_queue > 0)
1419 atomic_dec(&starget->target_busy);
1420 return 0;
1421}
1422
1423/*
1424 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1425 * return 0. We must end up running the queue again whenever 0 is
1426 * returned, else IO can hang.
1427 */
1428static inline int scsi_host_queue_ready(struct request_queue *q,
1429 struct Scsi_Host *shost,
1430 struct scsi_device *sdev,
1431 struct scsi_cmnd *cmd)
1432{
1433 if (atomic_read(&shost->host_blocked) > 0) {
1434 if (scsi_host_busy(shost) > 0)
1435 goto starved;
1436
1437 /*
1438 * unblock after host_blocked iterates to zero
1439 */
1440 if (atomic_dec_return(&shost->host_blocked) > 0)
1441 goto out_dec;
1442
1443 SCSI_LOG_MLQUEUE(3,
1444 shost_printk(KERN_INFO, shost,
1445 "unblocking host at zero depth\n"));
1446 }
1447
1448 if (shost->host_self_blocked)
1449 goto starved;
1450
1451 /* We're OK to process the command, so we can't be starved */
1452 if (!list_empty(&sdev->starved_entry)) {
1453 spin_lock_irq(shost->host_lock);
1454 if (!list_empty(&sdev->starved_entry))
1455 list_del_init(&sdev->starved_entry);
1456 spin_unlock_irq(shost->host_lock);
1457 }
1458
1459 __set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1460
1461 return 1;
1462
1463starved:
1464 spin_lock_irq(shost->host_lock);
1465 if (list_empty(&sdev->starved_entry))
1466 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1467 spin_unlock_irq(shost->host_lock);
1468out_dec:
1469 scsi_dec_host_busy(shost, cmd);
1470 return 0;
1471}
1472
1473/*
1474 * Busy state exporting function for request stacking drivers.
1475 *
1476 * For efficiency, no lock is taken to check the busy state of
1477 * shost/starget/sdev, since the returned value is not guaranteed and
1478 * may be changed after request stacking drivers call the function,
1479 * regardless of taking lock or not.
1480 *
1481 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1482 * needs to return 'not busy'. Otherwise, request stacking drivers
1483 * may hold requests forever.
1484 */
1485static bool scsi_mq_lld_busy(struct request_queue *q)
1486{
1487 struct scsi_device *sdev = q->queuedata;
1488 struct Scsi_Host *shost;
1489
1490 if (blk_queue_dying(q))
1491 return false;
1492
1493 shost = sdev->host;
1494
1495 /*
1496 * Ignore host/starget busy state.
1497 * Since block layer does not have a concept of fairness across
1498 * multiple queues, congestion of host/starget needs to be handled
1499 * in SCSI layer.
1500 */
1501 if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
1502 return true;
1503
1504 return false;
1505}
1506
1507/*
1508 * Block layer request completion callback. May be called from interrupt
1509 * context.
1510 */
1511static void scsi_complete(struct request *rq)
1512{
1513 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1514 enum scsi_disposition disposition;
1515
1516 INIT_LIST_HEAD(&cmd->eh_entry);
1517
1518 atomic_inc(&cmd->device->iodone_cnt);
1519 if (cmd->result)
1520 atomic_inc(&cmd->device->ioerr_cnt);
1521
1522 disposition = scsi_decide_disposition(cmd);
1523 if (disposition != SUCCESS && scsi_cmd_runtime_exceeced(cmd))
1524 disposition = SUCCESS;
1525
1526 scsi_log_completion(cmd, disposition);
1527
1528 switch (disposition) {
1529 case SUCCESS:
1530 scsi_finish_command(cmd);
1531 break;
1532 case NEEDS_RETRY:
1533 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
1534 break;
1535 case ADD_TO_MLQUEUE:
1536 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1537 break;
1538 default:
1539 scsi_eh_scmd_add(cmd);
1540 break;
1541 }
1542}
1543
1544/**
1545 * scsi_dispatch_cmd - Dispatch a command to the low-level driver.
1546 * @cmd: command block we are dispatching.
1547 *
1548 * Return: nonzero return request was rejected and device's queue needs to be
1549 * plugged.
1550 */
1551static int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
1552{
1553 struct Scsi_Host *host = cmd->device->host;
1554 int rtn = 0;
1555
1556 atomic_inc(&cmd->device->iorequest_cnt);
1557
1558 /* check if the device is still usable */
1559 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
1560 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
1561 * returns an immediate error upwards, and signals
1562 * that the device is no longer present */
1563 cmd->result = DID_NO_CONNECT << 16;
1564 goto done;
1565 }
1566
1567 /* Check to see if the scsi lld made this device blocked. */
1568 if (unlikely(scsi_device_blocked(cmd->device))) {
1569 /*
1570 * in blocked state, the command is just put back on
1571 * the device queue. The suspend state has already
1572 * blocked the queue so future requests should not
1573 * occur until the device transitions out of the
1574 * suspend state.
1575 */
1576 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1577 "queuecommand : device blocked\n"));
1578 atomic_dec(&cmd->device->iorequest_cnt);
1579 return SCSI_MLQUEUE_DEVICE_BUSY;
1580 }
1581
1582 /* Store the LUN value in cmnd, if needed. */
1583 if (cmd->device->lun_in_cdb)
1584 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
1585 (cmd->device->lun << 5 & 0xe0);
1586
1587 scsi_log_send(cmd);
1588
1589 /*
1590 * Before we queue this command, check if the command
1591 * length exceeds what the host adapter can handle.
1592 */
1593 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
1594 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1595 "queuecommand : command too long. "
1596 "cdb_size=%d host->max_cmd_len=%d\n",
1597 cmd->cmd_len, cmd->device->host->max_cmd_len));
1598 cmd->result = (DID_ABORT << 16);
1599 goto done;
1600 }
1601
1602 if (unlikely(host->shost_state == SHOST_DEL)) {
1603 cmd->result = (DID_NO_CONNECT << 16);
1604 goto done;
1605
1606 }
1607
1608 trace_scsi_dispatch_cmd_start(cmd);
1609 rtn = host->hostt->queuecommand(host, cmd);
1610 if (rtn) {
1611 atomic_dec(&cmd->device->iorequest_cnt);
1612 trace_scsi_dispatch_cmd_error(cmd, rtn);
1613 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
1614 rtn != SCSI_MLQUEUE_TARGET_BUSY)
1615 rtn = SCSI_MLQUEUE_HOST_BUSY;
1616
1617 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1618 "queuecommand : request rejected\n"));
1619 }
1620
1621 return rtn;
1622 done:
1623 scsi_done(cmd);
1624 return 0;
1625}
1626
1627/* Size in bytes of the sg-list stored in the scsi-mq command-private data. */
1628static unsigned int scsi_mq_inline_sgl_size(struct Scsi_Host *shost)
1629{
1630 return min_t(unsigned int, shost->sg_tablesize, SCSI_INLINE_SG_CNT) *
1631 sizeof(struct scatterlist);
1632}
1633
1634static blk_status_t scsi_prepare_cmd(struct request *req)
1635{
1636 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1637 struct scsi_device *sdev = req->q->queuedata;
1638 struct Scsi_Host *shost = sdev->host;
1639 bool in_flight = test_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1640 struct scatterlist *sg;
1641
1642 scsi_init_command(sdev, cmd);
1643
1644 cmd->eh_eflags = 0;
1645 cmd->prot_type = 0;
1646 cmd->prot_flags = 0;
1647 cmd->submitter = 0;
1648 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1649 cmd->underflow = 0;
1650 cmd->transfersize = 0;
1651 cmd->host_scribble = NULL;
1652 cmd->result = 0;
1653 cmd->extra_len = 0;
1654 cmd->state = 0;
1655 if (in_flight)
1656 __set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1657
1658 /*
1659 * Only clear the driver-private command data if the LLD does not supply
1660 * a function to initialize that data.
1661 */
1662 if (!shost->hostt->init_cmd_priv)
1663 memset(cmd + 1, 0, shost->hostt->cmd_size);
1664
1665 cmd->prot_op = SCSI_PROT_NORMAL;
1666 if (blk_rq_bytes(req))
1667 cmd->sc_data_direction = rq_dma_dir(req);
1668 else
1669 cmd->sc_data_direction = DMA_NONE;
1670
1671 sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
1672 cmd->sdb.table.sgl = sg;
1673
1674 if (scsi_host_get_prot(shost)) {
1675 memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer));
1676
1677 cmd->prot_sdb->table.sgl =
1678 (struct scatterlist *)(cmd->prot_sdb + 1);
1679 }
1680
1681 /*
1682 * Special handling for passthrough commands, which don't go to the ULP
1683 * at all:
1684 */
1685 if (blk_rq_is_passthrough(req))
1686 return scsi_setup_scsi_cmnd(sdev, req);
1687
1688 if (sdev->handler && sdev->handler->prep_fn) {
1689 blk_status_t ret = sdev->handler->prep_fn(sdev, req);
1690
1691 if (ret != BLK_STS_OK)
1692 return ret;
1693 }
1694
1695 /* Usually overridden by the ULP */
1696 cmd->allowed = 0;
1697 memset(cmd->cmnd, 0, sizeof(cmd->cmnd));
1698 return scsi_cmd_to_driver(cmd)->init_command(cmd);
1699}
1700
1701static void scsi_done_internal(struct scsi_cmnd *cmd, bool complete_directly)
1702{
1703 struct request *req = scsi_cmd_to_rq(cmd);
1704
1705 switch (cmd->submitter) {
1706 case SUBMITTED_BY_BLOCK_LAYER:
1707 break;
1708 case SUBMITTED_BY_SCSI_ERROR_HANDLER:
1709 return scsi_eh_done(cmd);
1710 case SUBMITTED_BY_SCSI_RESET_IOCTL:
1711 return;
1712 }
1713
1714 if (unlikely(blk_should_fake_timeout(scsi_cmd_to_rq(cmd)->q)))
1715 return;
1716 if (unlikely(test_and_set_bit(SCMD_STATE_COMPLETE, &cmd->state)))
1717 return;
1718 trace_scsi_dispatch_cmd_done(cmd);
1719
1720 if (complete_directly)
1721 blk_mq_complete_request_direct(req, scsi_complete);
1722 else
1723 blk_mq_complete_request(req);
1724}
1725
1726void scsi_done(struct scsi_cmnd *cmd)
1727{
1728 scsi_done_internal(cmd, false);
1729}
1730EXPORT_SYMBOL(scsi_done);
1731
1732void scsi_done_direct(struct scsi_cmnd *cmd)
1733{
1734 scsi_done_internal(cmd, true);
1735}
1736EXPORT_SYMBOL(scsi_done_direct);
1737
1738static void scsi_mq_put_budget(struct request_queue *q, int budget_token)
1739{
1740 struct scsi_device *sdev = q->queuedata;
1741
1742 sbitmap_put(&sdev->budget_map, budget_token);
1743}
1744
1745/*
1746 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
1747 * not change behaviour from the previous unplug mechanism, experimentation
1748 * may prove this needs changing.
1749 */
1750#define SCSI_QUEUE_DELAY 3
1751
1752static int scsi_mq_get_budget(struct request_queue *q)
1753{
1754 struct scsi_device *sdev = q->queuedata;
1755 int token = scsi_dev_queue_ready(q, sdev);
1756
1757 if (token >= 0)
1758 return token;
1759
1760 atomic_inc(&sdev->restarts);
1761
1762 /*
1763 * Orders atomic_inc(&sdev->restarts) and atomic_read(&sdev->device_busy).
1764 * .restarts must be incremented before .device_busy is read because the
1765 * code in scsi_run_queue_async() depends on the order of these operations.
1766 */
1767 smp_mb__after_atomic();
1768
1769 /*
1770 * If all in-flight requests originated from this LUN are completed
1771 * before reading .device_busy, sdev->device_busy will be observed as
1772 * zero, then blk_mq_delay_run_hw_queues() will dispatch this request
1773 * soon. Otherwise, completion of one of these requests will observe
1774 * the .restarts flag, and the request queue will be run for handling
1775 * this request, see scsi_end_request().
1776 */
1777 if (unlikely(scsi_device_busy(sdev) == 0 &&
1778 !scsi_device_blocked(sdev)))
1779 blk_mq_delay_run_hw_queues(sdev->request_queue, SCSI_QUEUE_DELAY);
1780 return -1;
1781}
1782
1783static void scsi_mq_set_rq_budget_token(struct request *req, int token)
1784{
1785 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1786
1787 cmd->budget_token = token;
1788}
1789
1790static int scsi_mq_get_rq_budget_token(struct request *req)
1791{
1792 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1793
1794 return cmd->budget_token;
1795}
1796
1797static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
1798 const struct blk_mq_queue_data *bd)
1799{
1800 struct request *req = bd->rq;
1801 struct request_queue *q = req->q;
1802 struct scsi_device *sdev = q->queuedata;
1803 struct Scsi_Host *shost = sdev->host;
1804 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1805 blk_status_t ret;
1806 int reason;
1807
1808 WARN_ON_ONCE(cmd->budget_token < 0);
1809
1810 /*
1811 * If the device is not in running state we will reject some or all
1812 * commands.
1813 */
1814 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
1815 ret = scsi_device_state_check(sdev, req);
1816 if (ret != BLK_STS_OK)
1817 goto out_put_budget;
1818 }
1819
1820 ret = BLK_STS_RESOURCE;
1821 if (!scsi_target_queue_ready(shost, sdev))
1822 goto out_put_budget;
1823 if (unlikely(scsi_host_in_recovery(shost))) {
1824 if (cmd->flags & SCMD_FAIL_IF_RECOVERING)
1825 ret = BLK_STS_OFFLINE;
1826 goto out_dec_target_busy;
1827 }
1828 if (!scsi_host_queue_ready(q, shost, sdev, cmd))
1829 goto out_dec_target_busy;
1830
1831 if (!(req->rq_flags & RQF_DONTPREP)) {
1832 ret = scsi_prepare_cmd(req);
1833 if (ret != BLK_STS_OK)
1834 goto out_dec_host_busy;
1835 req->rq_flags |= RQF_DONTPREP;
1836 } else {
1837 clear_bit(SCMD_STATE_COMPLETE, &cmd->state);
1838 }
1839
1840 cmd->flags &= SCMD_PRESERVED_FLAGS;
1841 if (sdev->simple_tags)
1842 cmd->flags |= SCMD_TAGGED;
1843 if (bd->last)
1844 cmd->flags |= SCMD_LAST;
1845
1846 scsi_set_resid(cmd, 0);
1847 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
1848 cmd->submitter = SUBMITTED_BY_BLOCK_LAYER;
1849
1850 blk_mq_start_request(req);
1851 reason = scsi_dispatch_cmd(cmd);
1852 if (reason) {
1853 scsi_set_blocked(cmd, reason);
1854 ret = BLK_STS_RESOURCE;
1855 goto out_dec_host_busy;
1856 }
1857
1858 return BLK_STS_OK;
1859
1860out_dec_host_busy:
1861 scsi_dec_host_busy(shost, cmd);
1862out_dec_target_busy:
1863 if (scsi_target(sdev)->can_queue > 0)
1864 atomic_dec(&scsi_target(sdev)->target_busy);
1865out_put_budget:
1866 scsi_mq_put_budget(q, cmd->budget_token);
1867 cmd->budget_token = -1;
1868 switch (ret) {
1869 case BLK_STS_OK:
1870 break;
1871 case BLK_STS_RESOURCE:
1872 case BLK_STS_ZONE_RESOURCE:
1873 if (scsi_device_blocked(sdev))
1874 ret = BLK_STS_DEV_RESOURCE;
1875 break;
1876 case BLK_STS_AGAIN:
1877 cmd->result = DID_BUS_BUSY << 16;
1878 if (req->rq_flags & RQF_DONTPREP)
1879 scsi_mq_uninit_cmd(cmd);
1880 break;
1881 default:
1882 if (unlikely(!scsi_device_online(sdev)))
1883 cmd->result = DID_NO_CONNECT << 16;
1884 else
1885 cmd->result = DID_ERROR << 16;
1886 /*
1887 * Make sure to release all allocated resources when
1888 * we hit an error, as we will never see this command
1889 * again.
1890 */
1891 if (req->rq_flags & RQF_DONTPREP)
1892 scsi_mq_uninit_cmd(cmd);
1893 scsi_run_queue_async(sdev);
1894 break;
1895 }
1896 return ret;
1897}
1898
1899static int scsi_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
1900 unsigned int hctx_idx, unsigned int numa_node)
1901{
1902 struct Scsi_Host *shost = set->driver_data;
1903 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1904 struct scatterlist *sg;
1905 int ret = 0;
1906
1907 cmd->sense_buffer =
1908 kmem_cache_alloc_node(scsi_sense_cache, GFP_KERNEL, numa_node);
1909 if (!cmd->sense_buffer)
1910 return -ENOMEM;
1911
1912 if (scsi_host_get_prot(shost)) {
1913 sg = (void *)cmd + sizeof(struct scsi_cmnd) +
1914 shost->hostt->cmd_size;
1915 cmd->prot_sdb = (void *)sg + scsi_mq_inline_sgl_size(shost);
1916 }
1917
1918 if (shost->hostt->init_cmd_priv) {
1919 ret = shost->hostt->init_cmd_priv(shost, cmd);
1920 if (ret < 0)
1921 kmem_cache_free(scsi_sense_cache, cmd->sense_buffer);
1922 }
1923
1924 return ret;
1925}
1926
1927static void scsi_mq_exit_request(struct blk_mq_tag_set *set, struct request *rq,
1928 unsigned int hctx_idx)
1929{
1930 struct Scsi_Host *shost = set->driver_data;
1931 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1932
1933 if (shost->hostt->exit_cmd_priv)
1934 shost->hostt->exit_cmd_priv(shost, cmd);
1935 kmem_cache_free(scsi_sense_cache, cmd->sense_buffer);
1936}
1937
1938
1939static int scsi_mq_poll(struct blk_mq_hw_ctx *hctx, struct io_comp_batch *iob)
1940{
1941 struct Scsi_Host *shost = hctx->driver_data;
1942
1943 if (shost->hostt->mq_poll)
1944 return shost->hostt->mq_poll(shost, hctx->queue_num);
1945
1946 return 0;
1947}
1948
1949static int scsi_init_hctx(struct blk_mq_hw_ctx *hctx, void *data,
1950 unsigned int hctx_idx)
1951{
1952 struct Scsi_Host *shost = data;
1953
1954 hctx->driver_data = shost;
1955 return 0;
1956}
1957
1958static void scsi_map_queues(struct blk_mq_tag_set *set)
1959{
1960 struct Scsi_Host *shost = container_of(set, struct Scsi_Host, tag_set);
1961
1962 if (shost->hostt->map_queues)
1963 return shost->hostt->map_queues(shost);
1964 blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]);
1965}
1966
1967void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
1968{
1969 struct device *dev = shost->dma_dev;
1970
1971 /*
1972 * this limit is imposed by hardware restrictions
1973 */
1974 blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
1975 SG_MAX_SEGMENTS));
1976
1977 if (scsi_host_prot_dma(shost)) {
1978 shost->sg_prot_tablesize =
1979 min_not_zero(shost->sg_prot_tablesize,
1980 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
1981 BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
1982 blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
1983 }
1984
1985 blk_queue_max_hw_sectors(q, shost->max_sectors);
1986 blk_queue_segment_boundary(q, shost->dma_boundary);
1987 dma_set_seg_boundary(dev, shost->dma_boundary);
1988
1989 blk_queue_max_segment_size(q, shost->max_segment_size);
1990 blk_queue_virt_boundary(q, shost->virt_boundary_mask);
1991 dma_set_max_seg_size(dev, queue_max_segment_size(q));
1992
1993 /*
1994 * Set a reasonable default alignment: The larger of 32-byte (dword),
1995 * which is a common minimum for HBAs, and the minimum DMA alignment,
1996 * which is set by the platform.
1997 *
1998 * Devices that require a bigger alignment can increase it later.
1999 */
2000 blk_queue_dma_alignment(q, max(4, dma_get_cache_alignment()) - 1);
2001}
2002EXPORT_SYMBOL_GPL(__scsi_init_queue);
2003
2004static const struct blk_mq_ops scsi_mq_ops_no_commit = {
2005 .get_budget = scsi_mq_get_budget,
2006 .put_budget = scsi_mq_put_budget,
2007 .queue_rq = scsi_queue_rq,
2008 .complete = scsi_complete,
2009 .timeout = scsi_timeout,
2010#ifdef CONFIG_BLK_DEBUG_FS
2011 .show_rq = scsi_show_rq,
2012#endif
2013 .init_request = scsi_mq_init_request,
2014 .exit_request = scsi_mq_exit_request,
2015 .cleanup_rq = scsi_cleanup_rq,
2016 .busy = scsi_mq_lld_busy,
2017 .map_queues = scsi_map_queues,
2018 .init_hctx = scsi_init_hctx,
2019 .poll = scsi_mq_poll,
2020 .set_rq_budget_token = scsi_mq_set_rq_budget_token,
2021 .get_rq_budget_token = scsi_mq_get_rq_budget_token,
2022};
2023
2024
2025static void scsi_commit_rqs(struct blk_mq_hw_ctx *hctx)
2026{
2027 struct Scsi_Host *shost = hctx->driver_data;
2028
2029 shost->hostt->commit_rqs(shost, hctx->queue_num);
2030}
2031
2032static const struct blk_mq_ops scsi_mq_ops = {
2033 .get_budget = scsi_mq_get_budget,
2034 .put_budget = scsi_mq_put_budget,
2035 .queue_rq = scsi_queue_rq,
2036 .commit_rqs = scsi_commit_rqs,
2037 .complete = scsi_complete,
2038 .timeout = scsi_timeout,
2039#ifdef CONFIG_BLK_DEBUG_FS
2040 .show_rq = scsi_show_rq,
2041#endif
2042 .init_request = scsi_mq_init_request,
2043 .exit_request = scsi_mq_exit_request,
2044 .cleanup_rq = scsi_cleanup_rq,
2045 .busy = scsi_mq_lld_busy,
2046 .map_queues = scsi_map_queues,
2047 .init_hctx = scsi_init_hctx,
2048 .poll = scsi_mq_poll,
2049 .set_rq_budget_token = scsi_mq_set_rq_budget_token,
2050 .get_rq_budget_token = scsi_mq_get_rq_budget_token,
2051};
2052
2053int scsi_mq_setup_tags(struct Scsi_Host *shost)
2054{
2055 unsigned int cmd_size, sgl_size;
2056 struct blk_mq_tag_set *tag_set = &shost->tag_set;
2057
2058 sgl_size = max_t(unsigned int, sizeof(struct scatterlist),
2059 scsi_mq_inline_sgl_size(shost));
2060 cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size;
2061 if (scsi_host_get_prot(shost))
2062 cmd_size += sizeof(struct scsi_data_buffer) +
2063 sizeof(struct scatterlist) * SCSI_INLINE_PROT_SG_CNT;
2064
2065 memset(tag_set, 0, sizeof(*tag_set));
2066 if (shost->hostt->commit_rqs)
2067 tag_set->ops = &scsi_mq_ops;
2068 else
2069 tag_set->ops = &scsi_mq_ops_no_commit;
2070 tag_set->nr_hw_queues = shost->nr_hw_queues ? : 1;
2071 tag_set->nr_maps = shost->nr_maps ? : 1;
2072 tag_set->queue_depth = shost->can_queue;
2073 tag_set->cmd_size = cmd_size;
2074 tag_set->numa_node = dev_to_node(shost->dma_dev);
2075 tag_set->flags = BLK_MQ_F_SHOULD_MERGE;
2076 tag_set->flags |=
2077 BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
2078 if (shost->queuecommand_may_block)
2079 tag_set->flags |= BLK_MQ_F_BLOCKING;
2080 tag_set->driver_data = shost;
2081 if (shost->host_tagset)
2082 tag_set->flags |= BLK_MQ_F_TAG_HCTX_SHARED;
2083
2084 return blk_mq_alloc_tag_set(tag_set);
2085}
2086
2087void scsi_mq_free_tags(struct kref *kref)
2088{
2089 struct Scsi_Host *shost = container_of(kref, typeof(*shost),
2090 tagset_refcnt);
2091
2092 blk_mq_free_tag_set(&shost->tag_set);
2093 complete(&shost->tagset_freed);
2094}
2095
2096/**
2097 * scsi_device_from_queue - return sdev associated with a request_queue
2098 * @q: The request queue to return the sdev from
2099 *
2100 * Return the sdev associated with a request queue or NULL if the
2101 * request_queue does not reference a SCSI device.
2102 */
2103struct scsi_device *scsi_device_from_queue(struct request_queue *q)
2104{
2105 struct scsi_device *sdev = NULL;
2106
2107 if (q->mq_ops == &scsi_mq_ops_no_commit ||
2108 q->mq_ops == &scsi_mq_ops)
2109 sdev = q->queuedata;
2110 if (!sdev || !get_device(&sdev->sdev_gendev))
2111 sdev = NULL;
2112
2113 return sdev;
2114}
2115/*
2116 * pktcdvd should have been integrated into the SCSI layers, but for historical
2117 * reasons like the old IDE driver it isn't. This export allows it to safely
2118 * probe if a given device is a SCSI one and only attach to that.
2119 */
2120#ifdef CONFIG_CDROM_PKTCDVD_MODULE
2121EXPORT_SYMBOL_GPL(scsi_device_from_queue);
2122#endif
2123
2124/**
2125 * scsi_block_requests - Utility function used by low-level drivers to prevent
2126 * further commands from being queued to the device.
2127 * @shost: host in question
2128 *
2129 * There is no timer nor any other means by which the requests get unblocked
2130 * other than the low-level driver calling scsi_unblock_requests().
2131 */
2132void scsi_block_requests(struct Scsi_Host *shost)
2133{
2134 shost->host_self_blocked = 1;
2135}
2136EXPORT_SYMBOL(scsi_block_requests);
2137
2138/**
2139 * scsi_unblock_requests - Utility function used by low-level drivers to allow
2140 * further commands to be queued to the device.
2141 * @shost: host in question
2142 *
2143 * There is no timer nor any other means by which the requests get unblocked
2144 * other than the low-level driver calling scsi_unblock_requests(). This is done
2145 * as an API function so that changes to the internals of the scsi mid-layer
2146 * won't require wholesale changes to drivers that use this feature.
2147 */
2148void scsi_unblock_requests(struct Scsi_Host *shost)
2149{
2150 shost->host_self_blocked = 0;
2151 scsi_run_host_queues(shost);
2152}
2153EXPORT_SYMBOL(scsi_unblock_requests);
2154
2155void scsi_exit_queue(void)
2156{
2157 kmem_cache_destroy(scsi_sense_cache);
2158}
2159
2160/**
2161 * scsi_mode_select - issue a mode select
2162 * @sdev: SCSI device to be queried
2163 * @pf: Page format bit (1 == standard, 0 == vendor specific)
2164 * @sp: Save page bit (0 == don't save, 1 == save)
2165 * @buffer: request buffer (may not be smaller than eight bytes)
2166 * @len: length of request buffer.
2167 * @timeout: command timeout
2168 * @retries: number of retries before failing
2169 * @data: returns a structure abstracting the mode header data
2170 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2171 * must be SCSI_SENSE_BUFFERSIZE big.
2172 *
2173 * Returns zero if successful; negative error number or scsi
2174 * status on error
2175 *
2176 */
2177int scsi_mode_select(struct scsi_device *sdev, int pf, int sp,
2178 unsigned char *buffer, int len, int timeout, int retries,
2179 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2180{
2181 unsigned char cmd[10];
2182 unsigned char *real_buffer;
2183 const struct scsi_exec_args exec_args = {
2184 .sshdr = sshdr,
2185 };
2186 int ret;
2187
2188 memset(cmd, 0, sizeof(cmd));
2189 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
2190
2191 /*
2192 * Use MODE SELECT(10) if the device asked for it or if the mode page
2193 * and the mode select header cannot fit within the maximumm 255 bytes
2194 * of the MODE SELECT(6) command.
2195 */
2196 if (sdev->use_10_for_ms ||
2197 len + 4 > 255 ||
2198 data->block_descriptor_length > 255) {
2199 if (len > 65535 - 8)
2200 return -EINVAL;
2201 real_buffer = kmalloc(8 + len, GFP_KERNEL);
2202 if (!real_buffer)
2203 return -ENOMEM;
2204 memcpy(real_buffer + 8, buffer, len);
2205 len += 8;
2206 real_buffer[0] = 0;
2207 real_buffer[1] = 0;
2208 real_buffer[2] = data->medium_type;
2209 real_buffer[3] = data->device_specific;
2210 real_buffer[4] = data->longlba ? 0x01 : 0;
2211 real_buffer[5] = 0;
2212 put_unaligned_be16(data->block_descriptor_length,
2213 &real_buffer[6]);
2214
2215 cmd[0] = MODE_SELECT_10;
2216 put_unaligned_be16(len, &cmd[7]);
2217 } else {
2218 if (data->longlba)
2219 return -EINVAL;
2220
2221 real_buffer = kmalloc(4 + len, GFP_KERNEL);
2222 if (!real_buffer)
2223 return -ENOMEM;
2224 memcpy(real_buffer + 4, buffer, len);
2225 len += 4;
2226 real_buffer[0] = 0;
2227 real_buffer[1] = data->medium_type;
2228 real_buffer[2] = data->device_specific;
2229 real_buffer[3] = data->block_descriptor_length;
2230
2231 cmd[0] = MODE_SELECT;
2232 cmd[4] = len;
2233 }
2234
2235 ret = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_OUT, real_buffer, len,
2236 timeout, retries, &exec_args);
2237 kfree(real_buffer);
2238 return ret;
2239}
2240EXPORT_SYMBOL_GPL(scsi_mode_select);
2241
2242/**
2243 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
2244 * @sdev: SCSI device to be queried
2245 * @dbd: set to prevent mode sense from returning block descriptors
2246 * @modepage: mode page being requested
2247 * @subpage: sub-page of the mode page being requested
2248 * @buffer: request buffer (may not be smaller than eight bytes)
2249 * @len: length of request buffer.
2250 * @timeout: command timeout
2251 * @retries: number of retries before failing
2252 * @data: returns a structure abstracting the mode header data
2253 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2254 * must be SCSI_SENSE_BUFFERSIZE big.
2255 *
2256 * Returns zero if successful, or a negative error number on failure
2257 */
2258int
2259scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, int subpage,
2260 unsigned char *buffer, int len, int timeout, int retries,
2261 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2262{
2263 unsigned char cmd[12];
2264 int use_10_for_ms;
2265 int header_length;
2266 int result;
2267 struct scsi_sense_hdr my_sshdr;
2268 struct scsi_failure failure_defs[] = {
2269 {
2270 .sense = UNIT_ATTENTION,
2271 .asc = SCMD_FAILURE_ASC_ANY,
2272 .ascq = SCMD_FAILURE_ASCQ_ANY,
2273 .allowed = retries,
2274 .result = SAM_STAT_CHECK_CONDITION,
2275 },
2276 {}
2277 };
2278 struct scsi_failures failures = {
2279 .failure_definitions = failure_defs,
2280 };
2281 const struct scsi_exec_args exec_args = {
2282 /* caller might not be interested in sense, but we need it */
2283 .sshdr = sshdr ? : &my_sshdr,
2284 .failures = &failures,
2285 };
2286
2287 memset(data, 0, sizeof(*data));
2288 memset(&cmd[0], 0, 12);
2289
2290 dbd = sdev->set_dbd_for_ms ? 8 : dbd;
2291 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
2292 cmd[2] = modepage;
2293 cmd[3] = subpage;
2294
2295 sshdr = exec_args.sshdr;
2296
2297 retry:
2298 use_10_for_ms = sdev->use_10_for_ms || len > 255;
2299
2300 if (use_10_for_ms) {
2301 if (len < 8 || len > 65535)
2302 return -EINVAL;
2303
2304 cmd[0] = MODE_SENSE_10;
2305 put_unaligned_be16(len, &cmd[7]);
2306 header_length = 8;
2307 } else {
2308 if (len < 4)
2309 return -EINVAL;
2310
2311 cmd[0] = MODE_SENSE;
2312 cmd[4] = len;
2313 header_length = 4;
2314 }
2315
2316 memset(buffer, 0, len);
2317
2318 result = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_IN, buffer, len,
2319 timeout, retries, &exec_args);
2320 if (result < 0)
2321 return result;
2322
2323 /* This code looks awful: what it's doing is making sure an
2324 * ILLEGAL REQUEST sense return identifies the actual command
2325 * byte as the problem. MODE_SENSE commands can return
2326 * ILLEGAL REQUEST if the code page isn't supported */
2327
2328 if (!scsi_status_is_good(result)) {
2329 if (scsi_sense_valid(sshdr)) {
2330 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
2331 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
2332 /*
2333 * Invalid command operation code: retry using
2334 * MODE SENSE(6) if this was a MODE SENSE(10)
2335 * request, except if the request mode page is
2336 * too large for MODE SENSE single byte
2337 * allocation length field.
2338 */
2339 if (use_10_for_ms) {
2340 if (len > 255)
2341 return -EIO;
2342 sdev->use_10_for_ms = 0;
2343 goto retry;
2344 }
2345 }
2346 }
2347 return -EIO;
2348 }
2349 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
2350 (modepage == 6 || modepage == 8))) {
2351 /* Initio breakage? */
2352 header_length = 0;
2353 data->length = 13;
2354 data->medium_type = 0;
2355 data->device_specific = 0;
2356 data->longlba = 0;
2357 data->block_descriptor_length = 0;
2358 } else if (use_10_for_ms) {
2359 data->length = get_unaligned_be16(&buffer[0]) + 2;
2360 data->medium_type = buffer[2];
2361 data->device_specific = buffer[3];
2362 data->longlba = buffer[4] & 0x01;
2363 data->block_descriptor_length = get_unaligned_be16(&buffer[6]);
2364 } else {
2365 data->length = buffer[0] + 1;
2366 data->medium_type = buffer[1];
2367 data->device_specific = buffer[2];
2368 data->block_descriptor_length = buffer[3];
2369 }
2370 data->header_length = header_length;
2371
2372 return 0;
2373}
2374EXPORT_SYMBOL(scsi_mode_sense);
2375
2376/**
2377 * scsi_test_unit_ready - test if unit is ready
2378 * @sdev: scsi device to change the state of.
2379 * @timeout: command timeout
2380 * @retries: number of retries before failing
2381 * @sshdr: outpout pointer for decoded sense information.
2382 *
2383 * Returns zero if unsuccessful or an error if TUR failed. For
2384 * removable media, UNIT_ATTENTION sets ->changed flag.
2385 **/
2386int
2387scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2388 struct scsi_sense_hdr *sshdr)
2389{
2390 char cmd[] = {
2391 TEST_UNIT_READY, 0, 0, 0, 0, 0,
2392 };
2393 const struct scsi_exec_args exec_args = {
2394 .sshdr = sshdr,
2395 };
2396 int result;
2397
2398 /* try to eat the UNIT_ATTENTION if there are enough retries */
2399 do {
2400 result = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_IN, NULL, 0,
2401 timeout, 1, &exec_args);
2402 if (sdev->removable && result > 0 && scsi_sense_valid(sshdr) &&
2403 sshdr->sense_key == UNIT_ATTENTION)
2404 sdev->changed = 1;
2405 } while (result > 0 && scsi_sense_valid(sshdr) &&
2406 sshdr->sense_key == UNIT_ATTENTION && --retries);
2407
2408 return result;
2409}
2410EXPORT_SYMBOL(scsi_test_unit_ready);
2411
2412/**
2413 * scsi_device_set_state - Take the given device through the device state model.
2414 * @sdev: scsi device to change the state of.
2415 * @state: state to change to.
2416 *
2417 * Returns zero if successful or an error if the requested
2418 * transition is illegal.
2419 */
2420int
2421scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2422{
2423 enum scsi_device_state oldstate = sdev->sdev_state;
2424
2425 if (state == oldstate)
2426 return 0;
2427
2428 switch (state) {
2429 case SDEV_CREATED:
2430 switch (oldstate) {
2431 case SDEV_CREATED_BLOCK:
2432 break;
2433 default:
2434 goto illegal;
2435 }
2436 break;
2437
2438 case SDEV_RUNNING:
2439 switch (oldstate) {
2440 case SDEV_CREATED:
2441 case SDEV_OFFLINE:
2442 case SDEV_TRANSPORT_OFFLINE:
2443 case SDEV_QUIESCE:
2444 case SDEV_BLOCK:
2445 break;
2446 default:
2447 goto illegal;
2448 }
2449 break;
2450
2451 case SDEV_QUIESCE:
2452 switch (oldstate) {
2453 case SDEV_RUNNING:
2454 case SDEV_OFFLINE:
2455 case SDEV_TRANSPORT_OFFLINE:
2456 break;
2457 default:
2458 goto illegal;
2459 }
2460 break;
2461
2462 case SDEV_OFFLINE:
2463 case SDEV_TRANSPORT_OFFLINE:
2464 switch (oldstate) {
2465 case SDEV_CREATED:
2466 case SDEV_RUNNING:
2467 case SDEV_QUIESCE:
2468 case SDEV_BLOCK:
2469 break;
2470 default:
2471 goto illegal;
2472 }
2473 break;
2474
2475 case SDEV_BLOCK:
2476 switch (oldstate) {
2477 case SDEV_RUNNING:
2478 case SDEV_CREATED_BLOCK:
2479 case SDEV_QUIESCE:
2480 case SDEV_OFFLINE:
2481 break;
2482 default:
2483 goto illegal;
2484 }
2485 break;
2486
2487 case SDEV_CREATED_BLOCK:
2488 switch (oldstate) {
2489 case SDEV_CREATED:
2490 break;
2491 default:
2492 goto illegal;
2493 }
2494 break;
2495
2496 case SDEV_CANCEL:
2497 switch (oldstate) {
2498 case SDEV_CREATED:
2499 case SDEV_RUNNING:
2500 case SDEV_QUIESCE:
2501 case SDEV_OFFLINE:
2502 case SDEV_TRANSPORT_OFFLINE:
2503 break;
2504 default:
2505 goto illegal;
2506 }
2507 break;
2508
2509 case SDEV_DEL:
2510 switch (oldstate) {
2511 case SDEV_CREATED:
2512 case SDEV_RUNNING:
2513 case SDEV_OFFLINE:
2514 case SDEV_TRANSPORT_OFFLINE:
2515 case SDEV_CANCEL:
2516 case SDEV_BLOCK:
2517 case SDEV_CREATED_BLOCK:
2518 break;
2519 default:
2520 goto illegal;
2521 }
2522 break;
2523
2524 }
2525 sdev->offline_already = false;
2526 sdev->sdev_state = state;
2527 return 0;
2528
2529 illegal:
2530 SCSI_LOG_ERROR_RECOVERY(1,
2531 sdev_printk(KERN_ERR, sdev,
2532 "Illegal state transition %s->%s",
2533 scsi_device_state_name(oldstate),
2534 scsi_device_state_name(state))
2535 );
2536 return -EINVAL;
2537}
2538EXPORT_SYMBOL(scsi_device_set_state);
2539
2540/**
2541 * scsi_evt_emit - emit a single SCSI device uevent
2542 * @sdev: associated SCSI device
2543 * @evt: event to emit
2544 *
2545 * Send a single uevent (scsi_event) to the associated scsi_device.
2546 */
2547static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2548{
2549 int idx = 0;
2550 char *envp[3];
2551
2552 switch (evt->evt_type) {
2553 case SDEV_EVT_MEDIA_CHANGE:
2554 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2555 break;
2556 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2557 scsi_rescan_device(sdev);
2558 envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2559 break;
2560 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2561 envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2562 break;
2563 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2564 envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2565 break;
2566 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2567 envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2568 break;
2569 case SDEV_EVT_LUN_CHANGE_REPORTED:
2570 envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2571 break;
2572 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2573 envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
2574 break;
2575 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2576 envp[idx++] = "SDEV_UA=POWER_ON_RESET_OCCURRED";
2577 break;
2578 default:
2579 /* do nothing */
2580 break;
2581 }
2582
2583 envp[idx++] = NULL;
2584
2585 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2586}
2587
2588/**
2589 * scsi_evt_thread - send a uevent for each scsi event
2590 * @work: work struct for scsi_device
2591 *
2592 * Dispatch queued events to their associated scsi_device kobjects
2593 * as uevents.
2594 */
2595void scsi_evt_thread(struct work_struct *work)
2596{
2597 struct scsi_device *sdev;
2598 enum scsi_device_event evt_type;
2599 LIST_HEAD(event_list);
2600
2601 sdev = container_of(work, struct scsi_device, event_work);
2602
2603 for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
2604 if (test_and_clear_bit(evt_type, sdev->pending_events))
2605 sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
2606
2607 while (1) {
2608 struct scsi_event *evt;
2609 struct list_head *this, *tmp;
2610 unsigned long flags;
2611
2612 spin_lock_irqsave(&sdev->list_lock, flags);
2613 list_splice_init(&sdev->event_list, &event_list);
2614 spin_unlock_irqrestore(&sdev->list_lock, flags);
2615
2616 if (list_empty(&event_list))
2617 break;
2618
2619 list_for_each_safe(this, tmp, &event_list) {
2620 evt = list_entry(this, struct scsi_event, node);
2621 list_del(&evt->node);
2622 scsi_evt_emit(sdev, evt);
2623 kfree(evt);
2624 }
2625 }
2626}
2627
2628/**
2629 * sdev_evt_send - send asserted event to uevent thread
2630 * @sdev: scsi_device event occurred on
2631 * @evt: event to send
2632 *
2633 * Assert scsi device event asynchronously.
2634 */
2635void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2636{
2637 unsigned long flags;
2638
2639#if 0
2640 /* FIXME: currently this check eliminates all media change events
2641 * for polled devices. Need to update to discriminate between AN
2642 * and polled events */
2643 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2644 kfree(evt);
2645 return;
2646 }
2647#endif
2648
2649 spin_lock_irqsave(&sdev->list_lock, flags);
2650 list_add_tail(&evt->node, &sdev->event_list);
2651 schedule_work(&sdev->event_work);
2652 spin_unlock_irqrestore(&sdev->list_lock, flags);
2653}
2654EXPORT_SYMBOL_GPL(sdev_evt_send);
2655
2656/**
2657 * sdev_evt_alloc - allocate a new scsi event
2658 * @evt_type: type of event to allocate
2659 * @gfpflags: GFP flags for allocation
2660 *
2661 * Allocates and returns a new scsi_event.
2662 */
2663struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2664 gfp_t gfpflags)
2665{
2666 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2667 if (!evt)
2668 return NULL;
2669
2670 evt->evt_type = evt_type;
2671 INIT_LIST_HEAD(&evt->node);
2672
2673 /* evt_type-specific initialization, if any */
2674 switch (evt_type) {
2675 case SDEV_EVT_MEDIA_CHANGE:
2676 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2677 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2678 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2679 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2680 case SDEV_EVT_LUN_CHANGE_REPORTED:
2681 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2682 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2683 default:
2684 /* do nothing */
2685 break;
2686 }
2687
2688 return evt;
2689}
2690EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2691
2692/**
2693 * sdev_evt_send_simple - send asserted event to uevent thread
2694 * @sdev: scsi_device event occurred on
2695 * @evt_type: type of event to send
2696 * @gfpflags: GFP flags for allocation
2697 *
2698 * Assert scsi device event asynchronously, given an event type.
2699 */
2700void sdev_evt_send_simple(struct scsi_device *sdev,
2701 enum scsi_device_event evt_type, gfp_t gfpflags)
2702{
2703 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2704 if (!evt) {
2705 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2706 evt_type);
2707 return;
2708 }
2709
2710 sdev_evt_send(sdev, evt);
2711}
2712EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2713
2714/**
2715 * scsi_device_quiesce - Block all commands except power management.
2716 * @sdev: scsi device to quiesce.
2717 *
2718 * This works by trying to transition to the SDEV_QUIESCE state
2719 * (which must be a legal transition). When the device is in this
2720 * state, only power management requests will be accepted, all others will
2721 * be deferred.
2722 *
2723 * Must be called with user context, may sleep.
2724 *
2725 * Returns zero if unsuccessful or an error if not.
2726 */
2727int
2728scsi_device_quiesce(struct scsi_device *sdev)
2729{
2730 struct request_queue *q = sdev->request_queue;
2731 int err;
2732
2733 /*
2734 * It is allowed to call scsi_device_quiesce() multiple times from
2735 * the same context but concurrent scsi_device_quiesce() calls are
2736 * not allowed.
2737 */
2738 WARN_ON_ONCE(sdev->quiesced_by && sdev->quiesced_by != current);
2739
2740 if (sdev->quiesced_by == current)
2741 return 0;
2742
2743 blk_set_pm_only(q);
2744
2745 blk_mq_freeze_queue(q);
2746 /*
2747 * Ensure that the effect of blk_set_pm_only() will be visible
2748 * for percpu_ref_tryget() callers that occur after the queue
2749 * unfreeze even if the queue was already frozen before this function
2750 * was called. See also https://lwn.net/Articles/573497/.
2751 */
2752 synchronize_rcu();
2753 blk_mq_unfreeze_queue(q);
2754
2755 mutex_lock(&sdev->state_mutex);
2756 err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2757 if (err == 0)
2758 sdev->quiesced_by = current;
2759 else
2760 blk_clear_pm_only(q);
2761 mutex_unlock(&sdev->state_mutex);
2762
2763 return err;
2764}
2765EXPORT_SYMBOL(scsi_device_quiesce);
2766
2767/**
2768 * scsi_device_resume - Restart user issued commands to a quiesced device.
2769 * @sdev: scsi device to resume.
2770 *
2771 * Moves the device from quiesced back to running and restarts the
2772 * queues.
2773 *
2774 * Must be called with user context, may sleep.
2775 */
2776void scsi_device_resume(struct scsi_device *sdev)
2777{
2778 /* check if the device state was mutated prior to resume, and if
2779 * so assume the state is being managed elsewhere (for example
2780 * device deleted during suspend)
2781 */
2782 mutex_lock(&sdev->state_mutex);
2783 if (sdev->sdev_state == SDEV_QUIESCE)
2784 scsi_device_set_state(sdev, SDEV_RUNNING);
2785 if (sdev->quiesced_by) {
2786 sdev->quiesced_by = NULL;
2787 blk_clear_pm_only(sdev->request_queue);
2788 }
2789 mutex_unlock(&sdev->state_mutex);
2790}
2791EXPORT_SYMBOL(scsi_device_resume);
2792
2793static void
2794device_quiesce_fn(struct scsi_device *sdev, void *data)
2795{
2796 scsi_device_quiesce(sdev);
2797}
2798
2799void
2800scsi_target_quiesce(struct scsi_target *starget)
2801{
2802 starget_for_each_device(starget, NULL, device_quiesce_fn);
2803}
2804EXPORT_SYMBOL(scsi_target_quiesce);
2805
2806static void
2807device_resume_fn(struct scsi_device *sdev, void *data)
2808{
2809 scsi_device_resume(sdev);
2810}
2811
2812void
2813scsi_target_resume(struct scsi_target *starget)
2814{
2815 starget_for_each_device(starget, NULL, device_resume_fn);
2816}
2817EXPORT_SYMBOL(scsi_target_resume);
2818
2819static int __scsi_internal_device_block_nowait(struct scsi_device *sdev)
2820{
2821 if (scsi_device_set_state(sdev, SDEV_BLOCK))
2822 return scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2823
2824 return 0;
2825}
2826
2827void scsi_start_queue(struct scsi_device *sdev)
2828{
2829 if (cmpxchg(&sdev->queue_stopped, 1, 0))
2830 blk_mq_unquiesce_queue(sdev->request_queue);
2831}
2832
2833static void scsi_stop_queue(struct scsi_device *sdev)
2834{
2835 /*
2836 * The atomic variable of ->queue_stopped covers that
2837 * blk_mq_quiesce_queue* is balanced with blk_mq_unquiesce_queue.
2838 *
2839 * The caller needs to wait until quiesce is done.
2840 */
2841 if (!cmpxchg(&sdev->queue_stopped, 0, 1))
2842 blk_mq_quiesce_queue_nowait(sdev->request_queue);
2843}
2844
2845/**
2846 * scsi_internal_device_block_nowait - try to transition to the SDEV_BLOCK state
2847 * @sdev: device to block
2848 *
2849 * Pause SCSI command processing on the specified device. Does not sleep.
2850 *
2851 * Returns zero if successful or a negative error code upon failure.
2852 *
2853 * Notes:
2854 * This routine transitions the device to the SDEV_BLOCK state (which must be
2855 * a legal transition). When the device is in this state, command processing
2856 * is paused until the device leaves the SDEV_BLOCK state. See also
2857 * scsi_internal_device_unblock_nowait().
2858 */
2859int scsi_internal_device_block_nowait(struct scsi_device *sdev)
2860{
2861 int ret = __scsi_internal_device_block_nowait(sdev);
2862
2863 /*
2864 * The device has transitioned to SDEV_BLOCK. Stop the
2865 * block layer from calling the midlayer with this device's
2866 * request queue.
2867 */
2868 if (!ret)
2869 scsi_stop_queue(sdev);
2870 return ret;
2871}
2872EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait);
2873
2874/**
2875 * scsi_device_block - try to transition to the SDEV_BLOCK state
2876 * @sdev: device to block
2877 * @data: dummy argument, ignored
2878 *
2879 * Pause SCSI command processing on the specified device. Callers must wait
2880 * until all ongoing scsi_queue_rq() calls have finished after this function
2881 * returns.
2882 *
2883 * Note:
2884 * This routine transitions the device to the SDEV_BLOCK state (which must be
2885 * a legal transition). When the device is in this state, command processing
2886 * is paused until the device leaves the SDEV_BLOCK state. See also
2887 * scsi_internal_device_unblock().
2888 */
2889static void scsi_device_block(struct scsi_device *sdev, void *data)
2890{
2891 int err;
2892 enum scsi_device_state state;
2893
2894 mutex_lock(&sdev->state_mutex);
2895 err = __scsi_internal_device_block_nowait(sdev);
2896 state = sdev->sdev_state;
2897 if (err == 0)
2898 /*
2899 * scsi_stop_queue() must be called with the state_mutex
2900 * held. Otherwise a simultaneous scsi_start_queue() call
2901 * might unquiesce the queue before we quiesce it.
2902 */
2903 scsi_stop_queue(sdev);
2904
2905 mutex_unlock(&sdev->state_mutex);
2906
2907 WARN_ONCE(err, "%s: failed to block %s in state %d\n",
2908 __func__, dev_name(&sdev->sdev_gendev), state);
2909}
2910
2911/**
2912 * scsi_internal_device_unblock_nowait - resume a device after a block request
2913 * @sdev: device to resume
2914 * @new_state: state to set the device to after unblocking
2915 *
2916 * Restart the device queue for a previously suspended SCSI device. Does not
2917 * sleep.
2918 *
2919 * Returns zero if successful or a negative error code upon failure.
2920 *
2921 * Notes:
2922 * This routine transitions the device to the SDEV_RUNNING state or to one of
2923 * the offline states (which must be a legal transition) allowing the midlayer
2924 * to goose the queue for this device.
2925 */
2926int scsi_internal_device_unblock_nowait(struct scsi_device *sdev,
2927 enum scsi_device_state new_state)
2928{
2929 switch (new_state) {
2930 case SDEV_RUNNING:
2931 case SDEV_TRANSPORT_OFFLINE:
2932 break;
2933 default:
2934 return -EINVAL;
2935 }
2936
2937 /*
2938 * Try to transition the scsi device to SDEV_RUNNING or one of the
2939 * offlined states and goose the device queue if successful.
2940 */
2941 switch (sdev->sdev_state) {
2942 case SDEV_BLOCK:
2943 case SDEV_TRANSPORT_OFFLINE:
2944 sdev->sdev_state = new_state;
2945 break;
2946 case SDEV_CREATED_BLOCK:
2947 if (new_state == SDEV_TRANSPORT_OFFLINE ||
2948 new_state == SDEV_OFFLINE)
2949 sdev->sdev_state = new_state;
2950 else
2951 sdev->sdev_state = SDEV_CREATED;
2952 break;
2953 case SDEV_CANCEL:
2954 case SDEV_OFFLINE:
2955 break;
2956 default:
2957 return -EINVAL;
2958 }
2959 scsi_start_queue(sdev);
2960
2961 return 0;
2962}
2963EXPORT_SYMBOL_GPL(scsi_internal_device_unblock_nowait);
2964
2965/**
2966 * scsi_internal_device_unblock - resume a device after a block request
2967 * @sdev: device to resume
2968 * @new_state: state to set the device to after unblocking
2969 *
2970 * Restart the device queue for a previously suspended SCSI device. May sleep.
2971 *
2972 * Returns zero if successful or a negative error code upon failure.
2973 *
2974 * Notes:
2975 * This routine transitions the device to the SDEV_RUNNING state or to one of
2976 * the offline states (which must be a legal transition) allowing the midlayer
2977 * to goose the queue for this device.
2978 */
2979static int scsi_internal_device_unblock(struct scsi_device *sdev,
2980 enum scsi_device_state new_state)
2981{
2982 int ret;
2983
2984 mutex_lock(&sdev->state_mutex);
2985 ret = scsi_internal_device_unblock_nowait(sdev, new_state);
2986 mutex_unlock(&sdev->state_mutex);
2987
2988 return ret;
2989}
2990
2991static int
2992target_block(struct device *dev, void *data)
2993{
2994 if (scsi_is_target_device(dev))
2995 starget_for_each_device(to_scsi_target(dev), NULL,
2996 scsi_device_block);
2997 return 0;
2998}
2999
3000/**
3001 * scsi_block_targets - transition all SCSI child devices to SDEV_BLOCK state
3002 * @dev: a parent device of one or more scsi_target devices
3003 * @shost: the Scsi_Host to which this device belongs
3004 *
3005 * Iterate over all children of @dev, which should be scsi_target devices,
3006 * and switch all subordinate scsi devices to SDEV_BLOCK state. Wait for
3007 * ongoing scsi_queue_rq() calls to finish. May sleep.
3008 *
3009 * Note:
3010 * @dev must not itself be a scsi_target device.
3011 */
3012void
3013scsi_block_targets(struct Scsi_Host *shost, struct device *dev)
3014{
3015 WARN_ON_ONCE(scsi_is_target_device(dev));
3016 device_for_each_child(dev, NULL, target_block);
3017 blk_mq_wait_quiesce_done(&shost->tag_set);
3018}
3019EXPORT_SYMBOL_GPL(scsi_block_targets);
3020
3021static void
3022device_unblock(struct scsi_device *sdev, void *data)
3023{
3024 scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
3025}
3026
3027static int
3028target_unblock(struct device *dev, void *data)
3029{
3030 if (scsi_is_target_device(dev))
3031 starget_for_each_device(to_scsi_target(dev), data,
3032 device_unblock);
3033 return 0;
3034}
3035
3036void
3037scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
3038{
3039 if (scsi_is_target_device(dev))
3040 starget_for_each_device(to_scsi_target(dev), &new_state,
3041 device_unblock);
3042 else
3043 device_for_each_child(dev, &new_state, target_unblock);
3044}
3045EXPORT_SYMBOL_GPL(scsi_target_unblock);
3046
3047/**
3048 * scsi_host_block - Try to transition all logical units to the SDEV_BLOCK state
3049 * @shost: device to block
3050 *
3051 * Pause SCSI command processing for all logical units associated with the SCSI
3052 * host and wait until pending scsi_queue_rq() calls have finished.
3053 *
3054 * Returns zero if successful or a negative error code upon failure.
3055 */
3056int
3057scsi_host_block(struct Scsi_Host *shost)
3058{
3059 struct scsi_device *sdev;
3060 int ret;
3061
3062 /*
3063 * Call scsi_internal_device_block_nowait so we can avoid
3064 * calling synchronize_rcu() for each LUN.
3065 */
3066 shost_for_each_device(sdev, shost) {
3067 mutex_lock(&sdev->state_mutex);
3068 ret = scsi_internal_device_block_nowait(sdev);
3069 mutex_unlock(&sdev->state_mutex);
3070 if (ret) {
3071 scsi_device_put(sdev);
3072 return ret;
3073 }
3074 }
3075
3076 /* Wait for ongoing scsi_queue_rq() calls to finish. */
3077 blk_mq_wait_quiesce_done(&shost->tag_set);
3078
3079 return 0;
3080}
3081EXPORT_SYMBOL_GPL(scsi_host_block);
3082
3083int
3084scsi_host_unblock(struct Scsi_Host *shost, int new_state)
3085{
3086 struct scsi_device *sdev;
3087 int ret = 0;
3088
3089 shost_for_each_device(sdev, shost) {
3090 ret = scsi_internal_device_unblock(sdev, new_state);
3091 if (ret) {
3092 scsi_device_put(sdev);
3093 break;
3094 }
3095 }
3096 return ret;
3097}
3098EXPORT_SYMBOL_GPL(scsi_host_unblock);
3099
3100/**
3101 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
3102 * @sgl: scatter-gather list
3103 * @sg_count: number of segments in sg
3104 * @offset: offset in bytes into sg, on return offset into the mapped area
3105 * @len: bytes to map, on return number of bytes mapped
3106 *
3107 * Returns virtual address of the start of the mapped page
3108 */
3109void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
3110 size_t *offset, size_t *len)
3111{
3112 int i;
3113 size_t sg_len = 0, len_complete = 0;
3114 struct scatterlist *sg;
3115 struct page *page;
3116
3117 WARN_ON(!irqs_disabled());
3118
3119 for_each_sg(sgl, sg, sg_count, i) {
3120 len_complete = sg_len; /* Complete sg-entries */
3121 sg_len += sg->length;
3122 if (sg_len > *offset)
3123 break;
3124 }
3125
3126 if (unlikely(i == sg_count)) {
3127 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
3128 "elements %d\n",
3129 __func__, sg_len, *offset, sg_count);
3130 WARN_ON(1);
3131 return NULL;
3132 }
3133
3134 /* Offset starting from the beginning of first page in this sg-entry */
3135 *offset = *offset - len_complete + sg->offset;
3136
3137 /* Assumption: contiguous pages can be accessed as "page + i" */
3138 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
3139 *offset &= ~PAGE_MASK;
3140
3141 /* Bytes in this sg-entry from *offset to the end of the page */
3142 sg_len = PAGE_SIZE - *offset;
3143 if (*len > sg_len)
3144 *len = sg_len;
3145
3146 return kmap_atomic(page);
3147}
3148EXPORT_SYMBOL(scsi_kmap_atomic_sg);
3149
3150/**
3151 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
3152 * @virt: virtual address to be unmapped
3153 */
3154void scsi_kunmap_atomic_sg(void *virt)
3155{
3156 kunmap_atomic(virt);
3157}
3158EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
3159
3160void sdev_disable_disk_events(struct scsi_device *sdev)
3161{
3162 atomic_inc(&sdev->disk_events_disable_depth);
3163}
3164EXPORT_SYMBOL(sdev_disable_disk_events);
3165
3166void sdev_enable_disk_events(struct scsi_device *sdev)
3167{
3168 if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0))
3169 return;
3170 atomic_dec(&sdev->disk_events_disable_depth);
3171}
3172EXPORT_SYMBOL(sdev_enable_disk_events);
3173
3174static unsigned char designator_prio(const unsigned char *d)
3175{
3176 if (d[1] & 0x30)
3177 /* not associated with LUN */
3178 return 0;
3179
3180 if (d[3] == 0)
3181 /* invalid length */
3182 return 0;
3183
3184 /*
3185 * Order of preference for lun descriptor:
3186 * - SCSI name string
3187 * - NAA IEEE Registered Extended
3188 * - EUI-64 based 16-byte
3189 * - EUI-64 based 12-byte
3190 * - NAA IEEE Registered
3191 * - NAA IEEE Extended
3192 * - EUI-64 based 8-byte
3193 * - SCSI name string (truncated)
3194 * - T10 Vendor ID
3195 * as longer descriptors reduce the likelyhood
3196 * of identification clashes.
3197 */
3198
3199 switch (d[1] & 0xf) {
3200 case 8:
3201 /* SCSI name string, variable-length UTF-8 */
3202 return 9;
3203 case 3:
3204 switch (d[4] >> 4) {
3205 case 6:
3206 /* NAA registered extended */
3207 return 8;
3208 case 5:
3209 /* NAA registered */
3210 return 5;
3211 case 4:
3212 /* NAA extended */
3213 return 4;
3214 case 3:
3215 /* NAA locally assigned */
3216 return 1;
3217 default:
3218 break;
3219 }
3220 break;
3221 case 2:
3222 switch (d[3]) {
3223 case 16:
3224 /* EUI64-based, 16 byte */
3225 return 7;
3226 case 12:
3227 /* EUI64-based, 12 byte */
3228 return 6;
3229 case 8:
3230 /* EUI64-based, 8 byte */
3231 return 3;
3232 default:
3233 break;
3234 }
3235 break;
3236 case 1:
3237 /* T10 vendor ID */
3238 return 1;
3239 default:
3240 break;
3241 }
3242
3243 return 0;
3244}
3245
3246/**
3247 * scsi_vpd_lun_id - return a unique device identification
3248 * @sdev: SCSI device
3249 * @id: buffer for the identification
3250 * @id_len: length of the buffer
3251 *
3252 * Copies a unique device identification into @id based
3253 * on the information in the VPD page 0x83 of the device.
3254 * The string will be formatted as a SCSI name string.
3255 *
3256 * Returns the length of the identification or error on failure.
3257 * If the identifier is longer than the supplied buffer the actual
3258 * identifier length is returned and the buffer is not zero-padded.
3259 */
3260int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len)
3261{
3262 u8 cur_id_prio = 0;
3263 u8 cur_id_size = 0;
3264 const unsigned char *d, *cur_id_str;
3265 const struct scsi_vpd *vpd_pg83;
3266 int id_size = -EINVAL;
3267
3268 rcu_read_lock();
3269 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3270 if (!vpd_pg83) {
3271 rcu_read_unlock();
3272 return -ENXIO;
3273 }
3274
3275 /* The id string must be at least 20 bytes + terminating NULL byte */
3276 if (id_len < 21) {
3277 rcu_read_unlock();
3278 return -EINVAL;
3279 }
3280
3281 memset(id, 0, id_len);
3282 for (d = vpd_pg83->data + 4;
3283 d < vpd_pg83->data + vpd_pg83->len;
3284 d += d[3] + 4) {
3285 u8 prio = designator_prio(d);
3286
3287 if (prio == 0 || cur_id_prio > prio)
3288 continue;
3289
3290 switch (d[1] & 0xf) {
3291 case 0x1:
3292 /* T10 Vendor ID */
3293 if (cur_id_size > d[3])
3294 break;
3295 cur_id_prio = prio;
3296 cur_id_size = d[3];
3297 if (cur_id_size + 4 > id_len)
3298 cur_id_size = id_len - 4;
3299 cur_id_str = d + 4;
3300 id_size = snprintf(id, id_len, "t10.%*pE",
3301 cur_id_size, cur_id_str);
3302 break;
3303 case 0x2:
3304 /* EUI-64 */
3305 cur_id_prio = prio;
3306 cur_id_size = d[3];
3307 cur_id_str = d + 4;
3308 switch (cur_id_size) {
3309 case 8:
3310 id_size = snprintf(id, id_len,
3311 "eui.%8phN",
3312 cur_id_str);
3313 break;
3314 case 12:
3315 id_size = snprintf(id, id_len,
3316 "eui.%12phN",
3317 cur_id_str);
3318 break;
3319 case 16:
3320 id_size = snprintf(id, id_len,
3321 "eui.%16phN",
3322 cur_id_str);
3323 break;
3324 default:
3325 break;
3326 }
3327 break;
3328 case 0x3:
3329 /* NAA */
3330 cur_id_prio = prio;
3331 cur_id_size = d[3];
3332 cur_id_str = d + 4;
3333 switch (cur_id_size) {
3334 case 8:
3335 id_size = snprintf(id, id_len,
3336 "naa.%8phN",
3337 cur_id_str);
3338 break;
3339 case 16:
3340 id_size = snprintf(id, id_len,
3341 "naa.%16phN",
3342 cur_id_str);
3343 break;
3344 default:
3345 break;
3346 }
3347 break;
3348 case 0x8:
3349 /* SCSI name string */
3350 if (cur_id_size > d[3])
3351 break;
3352 /* Prefer others for truncated descriptor */
3353 if (d[3] > id_len) {
3354 prio = 2;
3355 if (cur_id_prio > prio)
3356 break;
3357 }
3358 cur_id_prio = prio;
3359 cur_id_size = id_size = d[3];
3360 cur_id_str = d + 4;
3361 if (cur_id_size >= id_len)
3362 cur_id_size = id_len - 1;
3363 memcpy(id, cur_id_str, cur_id_size);
3364 break;
3365 default:
3366 break;
3367 }
3368 }
3369 rcu_read_unlock();
3370
3371 return id_size;
3372}
3373EXPORT_SYMBOL(scsi_vpd_lun_id);
3374
3375/*
3376 * scsi_vpd_tpg_id - return a target port group identifier
3377 * @sdev: SCSI device
3378 *
3379 * Returns the Target Port Group identifier from the information
3380 * froom VPD page 0x83 of the device.
3381 *
3382 * Returns the identifier or error on failure.
3383 */
3384int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id)
3385{
3386 const unsigned char *d;
3387 const struct scsi_vpd *vpd_pg83;
3388 int group_id = -EAGAIN, rel_port = -1;
3389
3390 rcu_read_lock();
3391 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3392 if (!vpd_pg83) {
3393 rcu_read_unlock();
3394 return -ENXIO;
3395 }
3396
3397 d = vpd_pg83->data + 4;
3398 while (d < vpd_pg83->data + vpd_pg83->len) {
3399 switch (d[1] & 0xf) {
3400 case 0x4:
3401 /* Relative target port */
3402 rel_port = get_unaligned_be16(&d[6]);
3403 break;
3404 case 0x5:
3405 /* Target port group */
3406 group_id = get_unaligned_be16(&d[6]);
3407 break;
3408 default:
3409 break;
3410 }
3411 d += d[3] + 4;
3412 }
3413 rcu_read_unlock();
3414
3415 if (group_id >= 0 && rel_id && rel_port != -1)
3416 *rel_id = rel_port;
3417
3418 return group_id;
3419}
3420EXPORT_SYMBOL(scsi_vpd_tpg_id);
3421
3422/**
3423 * scsi_build_sense - build sense data for a command
3424 * @scmd: scsi command for which the sense should be formatted
3425 * @desc: Sense format (non-zero == descriptor format,
3426 * 0 == fixed format)
3427 * @key: Sense key
3428 * @asc: Additional sense code
3429 * @ascq: Additional sense code qualifier
3430 *
3431 **/
3432void scsi_build_sense(struct scsi_cmnd *scmd, int desc, u8 key, u8 asc, u8 ascq)
3433{
3434 scsi_build_sense_buffer(desc, scmd->sense_buffer, key, asc, ascq);
3435 scmd->result = SAM_STAT_CHECK_CONDITION;
3436}
3437EXPORT_SYMBOL_GPL(scsi_build_sense);
3438
3439#ifdef CONFIG_SCSI_LIB_KUNIT_TEST
3440#include "scsi_lib_test.c"
3441#endif
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 1999 Eric Youngdale
4 * Copyright (C) 2014 Christoph Hellwig
5 *
6 * SCSI queueing library.
7 * Initial versions: Eric Youngdale (eric@andante.org).
8 * Based upon conversations with large numbers
9 * of people at Linux Expo.
10 */
11
12#include <linux/bio.h>
13#include <linux/bitops.h>
14#include <linux/blkdev.h>
15#include <linux/completion.h>
16#include <linux/kernel.h>
17#include <linux/export.h>
18#include <linux/init.h>
19#include <linux/pci.h>
20#include <linux/delay.h>
21#include <linux/hardirq.h>
22#include <linux/scatterlist.h>
23#include <linux/blk-mq.h>
24#include <linux/blk-integrity.h>
25#include <linux/ratelimit.h>
26#include <asm/unaligned.h>
27
28#include <scsi/scsi.h>
29#include <scsi/scsi_cmnd.h>
30#include <scsi/scsi_dbg.h>
31#include <scsi/scsi_device.h>
32#include <scsi/scsi_driver.h>
33#include <scsi/scsi_eh.h>
34#include <scsi/scsi_host.h>
35#include <scsi/scsi_transport.h> /* __scsi_init_queue() */
36#include <scsi/scsi_dh.h>
37
38#include <trace/events/scsi.h>
39
40#include "scsi_debugfs.h"
41#include "scsi_priv.h"
42#include "scsi_logging.h"
43
44/*
45 * Size of integrity metadata is usually small, 1 inline sg should
46 * cover normal cases.
47 */
48#ifdef CONFIG_ARCH_NO_SG_CHAIN
49#define SCSI_INLINE_PROT_SG_CNT 0
50#define SCSI_INLINE_SG_CNT 0
51#else
52#define SCSI_INLINE_PROT_SG_CNT 1
53#define SCSI_INLINE_SG_CNT 2
54#endif
55
56static struct kmem_cache *scsi_sense_cache;
57static DEFINE_MUTEX(scsi_sense_cache_mutex);
58
59static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd);
60
61int scsi_init_sense_cache(struct Scsi_Host *shost)
62{
63 int ret = 0;
64
65 mutex_lock(&scsi_sense_cache_mutex);
66 if (!scsi_sense_cache) {
67 scsi_sense_cache =
68 kmem_cache_create_usercopy("scsi_sense_cache",
69 SCSI_SENSE_BUFFERSIZE, 0, SLAB_HWCACHE_ALIGN,
70 0, SCSI_SENSE_BUFFERSIZE, NULL);
71 if (!scsi_sense_cache)
72 ret = -ENOMEM;
73 }
74 mutex_unlock(&scsi_sense_cache_mutex);
75 return ret;
76}
77
78static void
79scsi_set_blocked(struct scsi_cmnd *cmd, int reason)
80{
81 struct Scsi_Host *host = cmd->device->host;
82 struct scsi_device *device = cmd->device;
83 struct scsi_target *starget = scsi_target(device);
84
85 /*
86 * Set the appropriate busy bit for the device/host.
87 *
88 * If the host/device isn't busy, assume that something actually
89 * completed, and that we should be able to queue a command now.
90 *
91 * Note that the prior mid-layer assumption that any host could
92 * always queue at least one command is now broken. The mid-layer
93 * will implement a user specifiable stall (see
94 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
95 * if a command is requeued with no other commands outstanding
96 * either for the device or for the host.
97 */
98 switch (reason) {
99 case SCSI_MLQUEUE_HOST_BUSY:
100 atomic_set(&host->host_blocked, host->max_host_blocked);
101 break;
102 case SCSI_MLQUEUE_DEVICE_BUSY:
103 case SCSI_MLQUEUE_EH_RETRY:
104 atomic_set(&device->device_blocked,
105 device->max_device_blocked);
106 break;
107 case SCSI_MLQUEUE_TARGET_BUSY:
108 atomic_set(&starget->target_blocked,
109 starget->max_target_blocked);
110 break;
111 }
112}
113
114static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd, unsigned long msecs)
115{
116 struct request *rq = scsi_cmd_to_rq(cmd);
117
118 if (rq->rq_flags & RQF_DONTPREP) {
119 rq->rq_flags &= ~RQF_DONTPREP;
120 scsi_mq_uninit_cmd(cmd);
121 } else {
122 WARN_ON_ONCE(true);
123 }
124
125 if (msecs) {
126 blk_mq_requeue_request(rq, false);
127 blk_mq_delay_kick_requeue_list(rq->q, msecs);
128 } else
129 blk_mq_requeue_request(rq, true);
130}
131
132/**
133 * __scsi_queue_insert - private queue insertion
134 * @cmd: The SCSI command being requeued
135 * @reason: The reason for the requeue
136 * @unbusy: Whether the queue should be unbusied
137 *
138 * This is a private queue insertion. The public interface
139 * scsi_queue_insert() always assumes the queue should be unbusied
140 * because it's always called before the completion. This function is
141 * for a requeue after completion, which should only occur in this
142 * file.
143 */
144static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy)
145{
146 struct scsi_device *device = cmd->device;
147
148 SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd,
149 "Inserting command %p into mlqueue\n", cmd));
150
151 scsi_set_blocked(cmd, reason);
152
153 /*
154 * Decrement the counters, since these commands are no longer
155 * active on the host/device.
156 */
157 if (unbusy)
158 scsi_device_unbusy(device, cmd);
159
160 /*
161 * Requeue this command. It will go before all other commands
162 * that are already in the queue. Schedule requeue work under
163 * lock such that the kblockd_schedule_work() call happens
164 * before blk_mq_destroy_queue() finishes.
165 */
166 cmd->result = 0;
167
168 blk_mq_requeue_request(scsi_cmd_to_rq(cmd), true);
169}
170
171/**
172 * scsi_queue_insert - Reinsert a command in the queue.
173 * @cmd: command that we are adding to queue.
174 * @reason: why we are inserting command to queue.
175 *
176 * We do this for one of two cases. Either the host is busy and it cannot accept
177 * any more commands for the time being, or the device returned QUEUE_FULL and
178 * can accept no more commands.
179 *
180 * Context: This could be called either from an interrupt context or a normal
181 * process context.
182 */
183void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
184{
185 __scsi_queue_insert(cmd, reason, true);
186}
187
188
189/**
190 * __scsi_execute - insert request and wait for the result
191 * @sdev: scsi device
192 * @cmd: scsi command
193 * @data_direction: data direction
194 * @buffer: data buffer
195 * @bufflen: len of buffer
196 * @sense: optional sense buffer
197 * @sshdr: optional decoded sense header
198 * @timeout: request timeout in HZ
199 * @retries: number of times to retry request
200 * @flags: flags for ->cmd_flags
201 * @rq_flags: flags for ->rq_flags
202 * @resid: optional residual length
203 *
204 * Returns the scsi_cmnd result field if a command was executed, or a negative
205 * Linux error code if we didn't get that far.
206 */
207int __scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
208 int data_direction, void *buffer, unsigned bufflen,
209 unsigned char *sense, struct scsi_sense_hdr *sshdr,
210 int timeout, int retries, blk_opf_t flags,
211 req_flags_t rq_flags, int *resid)
212{
213 struct request *req;
214 struct scsi_cmnd *scmd;
215 int ret;
216
217 req = scsi_alloc_request(sdev->request_queue,
218 data_direction == DMA_TO_DEVICE ?
219 REQ_OP_DRV_OUT : REQ_OP_DRV_IN,
220 rq_flags & RQF_PM ? BLK_MQ_REQ_PM : 0);
221 if (IS_ERR(req))
222 return PTR_ERR(req);
223
224 if (bufflen) {
225 ret = blk_rq_map_kern(sdev->request_queue, req,
226 buffer, bufflen, GFP_NOIO);
227 if (ret)
228 goto out;
229 }
230 scmd = blk_mq_rq_to_pdu(req);
231 scmd->cmd_len = COMMAND_SIZE(cmd[0]);
232 memcpy(scmd->cmnd, cmd, scmd->cmd_len);
233 scmd->allowed = retries;
234 req->timeout = timeout;
235 req->cmd_flags |= flags;
236 req->rq_flags |= rq_flags | RQF_QUIET;
237
238 /*
239 * head injection *required* here otherwise quiesce won't work
240 */
241 blk_execute_rq(req, true);
242
243 /*
244 * Some devices (USB mass-storage in particular) may transfer
245 * garbage data together with a residue indicating that the data
246 * is invalid. Prevent the garbage from being misinterpreted
247 * and prevent security leaks by zeroing out the excess data.
248 */
249 if (unlikely(scmd->resid_len > 0 && scmd->resid_len <= bufflen))
250 memset(buffer + bufflen - scmd->resid_len, 0, scmd->resid_len);
251
252 if (resid)
253 *resid = scmd->resid_len;
254 if (sense && scmd->sense_len)
255 memcpy(sense, scmd->sense_buffer, SCSI_SENSE_BUFFERSIZE);
256 if (sshdr)
257 scsi_normalize_sense(scmd->sense_buffer, scmd->sense_len,
258 sshdr);
259 ret = scmd->result;
260 out:
261 blk_mq_free_request(req);
262
263 return ret;
264}
265EXPORT_SYMBOL(__scsi_execute);
266
267/*
268 * Wake up the error handler if necessary. Avoid as follows that the error
269 * handler is not woken up if host in-flight requests number ==
270 * shost->host_failed: use call_rcu() in scsi_eh_scmd_add() in combination
271 * with an RCU read lock in this function to ensure that this function in
272 * its entirety either finishes before scsi_eh_scmd_add() increases the
273 * host_failed counter or that it notices the shost state change made by
274 * scsi_eh_scmd_add().
275 */
276static void scsi_dec_host_busy(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
277{
278 unsigned long flags;
279
280 rcu_read_lock();
281 __clear_bit(SCMD_STATE_INFLIGHT, &cmd->state);
282 if (unlikely(scsi_host_in_recovery(shost))) {
283 spin_lock_irqsave(shost->host_lock, flags);
284 if (shost->host_failed || shost->host_eh_scheduled)
285 scsi_eh_wakeup(shost);
286 spin_unlock_irqrestore(shost->host_lock, flags);
287 }
288 rcu_read_unlock();
289}
290
291void scsi_device_unbusy(struct scsi_device *sdev, struct scsi_cmnd *cmd)
292{
293 struct Scsi_Host *shost = sdev->host;
294 struct scsi_target *starget = scsi_target(sdev);
295
296 scsi_dec_host_busy(shost, cmd);
297
298 if (starget->can_queue > 0)
299 atomic_dec(&starget->target_busy);
300
301 sbitmap_put(&sdev->budget_map, cmd->budget_token);
302 cmd->budget_token = -1;
303}
304
305static void scsi_kick_queue(struct request_queue *q)
306{
307 blk_mq_run_hw_queues(q, false);
308}
309
310/*
311 * Kick the queue of SCSI device @sdev if @sdev != current_sdev. Called with
312 * interrupts disabled.
313 */
314static void scsi_kick_sdev_queue(struct scsi_device *sdev, void *data)
315{
316 struct scsi_device *current_sdev = data;
317
318 if (sdev != current_sdev)
319 blk_mq_run_hw_queues(sdev->request_queue, true);
320}
321
322/*
323 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
324 * and call blk_run_queue for all the scsi_devices on the target -
325 * including current_sdev first.
326 *
327 * Called with *no* scsi locks held.
328 */
329static void scsi_single_lun_run(struct scsi_device *current_sdev)
330{
331 struct Scsi_Host *shost = current_sdev->host;
332 struct scsi_target *starget = scsi_target(current_sdev);
333 unsigned long flags;
334
335 spin_lock_irqsave(shost->host_lock, flags);
336 starget->starget_sdev_user = NULL;
337 spin_unlock_irqrestore(shost->host_lock, flags);
338
339 /*
340 * Call blk_run_queue for all LUNs on the target, starting with
341 * current_sdev. We race with others (to set starget_sdev_user),
342 * but in most cases, we will be first. Ideally, each LU on the
343 * target would get some limited time or requests on the target.
344 */
345 scsi_kick_queue(current_sdev->request_queue);
346
347 spin_lock_irqsave(shost->host_lock, flags);
348 if (!starget->starget_sdev_user)
349 __starget_for_each_device(starget, current_sdev,
350 scsi_kick_sdev_queue);
351 spin_unlock_irqrestore(shost->host_lock, flags);
352}
353
354static inline bool scsi_device_is_busy(struct scsi_device *sdev)
355{
356 if (scsi_device_busy(sdev) >= sdev->queue_depth)
357 return true;
358 if (atomic_read(&sdev->device_blocked) > 0)
359 return true;
360 return false;
361}
362
363static inline bool scsi_target_is_busy(struct scsi_target *starget)
364{
365 if (starget->can_queue > 0) {
366 if (atomic_read(&starget->target_busy) >= starget->can_queue)
367 return true;
368 if (atomic_read(&starget->target_blocked) > 0)
369 return true;
370 }
371 return false;
372}
373
374static inline bool scsi_host_is_busy(struct Scsi_Host *shost)
375{
376 if (atomic_read(&shost->host_blocked) > 0)
377 return true;
378 if (shost->host_self_blocked)
379 return true;
380 return false;
381}
382
383static void scsi_starved_list_run(struct Scsi_Host *shost)
384{
385 LIST_HEAD(starved_list);
386 struct scsi_device *sdev;
387 unsigned long flags;
388
389 spin_lock_irqsave(shost->host_lock, flags);
390 list_splice_init(&shost->starved_list, &starved_list);
391
392 while (!list_empty(&starved_list)) {
393 struct request_queue *slq;
394
395 /*
396 * As long as shost is accepting commands and we have
397 * starved queues, call blk_run_queue. scsi_request_fn
398 * drops the queue_lock and can add us back to the
399 * starved_list.
400 *
401 * host_lock protects the starved_list and starved_entry.
402 * scsi_request_fn must get the host_lock before checking
403 * or modifying starved_list or starved_entry.
404 */
405 if (scsi_host_is_busy(shost))
406 break;
407
408 sdev = list_entry(starved_list.next,
409 struct scsi_device, starved_entry);
410 list_del_init(&sdev->starved_entry);
411 if (scsi_target_is_busy(scsi_target(sdev))) {
412 list_move_tail(&sdev->starved_entry,
413 &shost->starved_list);
414 continue;
415 }
416
417 /*
418 * Once we drop the host lock, a racing scsi_remove_device()
419 * call may remove the sdev from the starved list and destroy
420 * it and the queue. Mitigate by taking a reference to the
421 * queue and never touching the sdev again after we drop the
422 * host lock. Note: if __scsi_remove_device() invokes
423 * blk_mq_destroy_queue() before the queue is run from this
424 * function then blk_run_queue() will return immediately since
425 * blk_mq_destroy_queue() marks the queue with QUEUE_FLAG_DYING.
426 */
427 slq = sdev->request_queue;
428 if (!blk_get_queue(slq))
429 continue;
430 spin_unlock_irqrestore(shost->host_lock, flags);
431
432 scsi_kick_queue(slq);
433 blk_put_queue(slq);
434
435 spin_lock_irqsave(shost->host_lock, flags);
436 }
437 /* put any unprocessed entries back */
438 list_splice(&starved_list, &shost->starved_list);
439 spin_unlock_irqrestore(shost->host_lock, flags);
440}
441
442/**
443 * scsi_run_queue - Select a proper request queue to serve next.
444 * @q: last request's queue
445 *
446 * The previous command was completely finished, start a new one if possible.
447 */
448static void scsi_run_queue(struct request_queue *q)
449{
450 struct scsi_device *sdev = q->queuedata;
451
452 if (scsi_target(sdev)->single_lun)
453 scsi_single_lun_run(sdev);
454 if (!list_empty(&sdev->host->starved_list))
455 scsi_starved_list_run(sdev->host);
456
457 blk_mq_run_hw_queues(q, false);
458}
459
460void scsi_requeue_run_queue(struct work_struct *work)
461{
462 struct scsi_device *sdev;
463 struct request_queue *q;
464
465 sdev = container_of(work, struct scsi_device, requeue_work);
466 q = sdev->request_queue;
467 scsi_run_queue(q);
468}
469
470void scsi_run_host_queues(struct Scsi_Host *shost)
471{
472 struct scsi_device *sdev;
473
474 shost_for_each_device(sdev, shost)
475 scsi_run_queue(sdev->request_queue);
476}
477
478static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
479{
480 if (!blk_rq_is_passthrough(scsi_cmd_to_rq(cmd))) {
481 struct scsi_driver *drv = scsi_cmd_to_driver(cmd);
482
483 if (drv->uninit_command)
484 drv->uninit_command(cmd);
485 }
486}
487
488void scsi_free_sgtables(struct scsi_cmnd *cmd)
489{
490 if (cmd->sdb.table.nents)
491 sg_free_table_chained(&cmd->sdb.table,
492 SCSI_INLINE_SG_CNT);
493 if (scsi_prot_sg_count(cmd))
494 sg_free_table_chained(&cmd->prot_sdb->table,
495 SCSI_INLINE_PROT_SG_CNT);
496}
497EXPORT_SYMBOL_GPL(scsi_free_sgtables);
498
499static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
500{
501 scsi_free_sgtables(cmd);
502 scsi_uninit_cmd(cmd);
503}
504
505static void scsi_run_queue_async(struct scsi_device *sdev)
506{
507 if (scsi_target(sdev)->single_lun ||
508 !list_empty(&sdev->host->starved_list)) {
509 kblockd_schedule_work(&sdev->requeue_work);
510 } else {
511 /*
512 * smp_mb() present in sbitmap_queue_clear() or implied in
513 * .end_io is for ordering writing .device_busy in
514 * scsi_device_unbusy() and reading sdev->restarts.
515 */
516 int old = atomic_read(&sdev->restarts);
517
518 /*
519 * ->restarts has to be kept as non-zero if new budget
520 * contention occurs.
521 *
522 * No need to run queue when either another re-run
523 * queue wins in updating ->restarts or a new budget
524 * contention occurs.
525 */
526 if (old && atomic_cmpxchg(&sdev->restarts, old, 0) == old)
527 blk_mq_run_hw_queues(sdev->request_queue, true);
528 }
529}
530
531/* Returns false when no more bytes to process, true if there are more */
532static bool scsi_end_request(struct request *req, blk_status_t error,
533 unsigned int bytes)
534{
535 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
536 struct scsi_device *sdev = cmd->device;
537 struct request_queue *q = sdev->request_queue;
538
539 if (blk_update_request(req, error, bytes))
540 return true;
541
542 // XXX:
543 if (blk_queue_add_random(q))
544 add_disk_randomness(req->q->disk);
545
546 if (!blk_rq_is_passthrough(req)) {
547 WARN_ON_ONCE(!(cmd->flags & SCMD_INITIALIZED));
548 cmd->flags &= ~SCMD_INITIALIZED;
549 }
550
551 /*
552 * Calling rcu_barrier() is not necessary here because the
553 * SCSI error handler guarantees that the function called by
554 * call_rcu() has been called before scsi_end_request() is
555 * called.
556 */
557 destroy_rcu_head(&cmd->rcu);
558
559 /*
560 * In the MQ case the command gets freed by __blk_mq_end_request,
561 * so we have to do all cleanup that depends on it earlier.
562 *
563 * We also can't kick the queues from irq context, so we
564 * will have to defer it to a workqueue.
565 */
566 scsi_mq_uninit_cmd(cmd);
567
568 /*
569 * queue is still alive, so grab the ref for preventing it
570 * from being cleaned up during running queue.
571 */
572 percpu_ref_get(&q->q_usage_counter);
573
574 __blk_mq_end_request(req, error);
575
576 scsi_run_queue_async(sdev);
577
578 percpu_ref_put(&q->q_usage_counter);
579 return false;
580}
581
582static inline u8 get_scsi_ml_byte(int result)
583{
584 return (result >> 8) & 0xff;
585}
586
587/**
588 * scsi_result_to_blk_status - translate a SCSI result code into blk_status_t
589 * @result: scsi error code
590 *
591 * Translate a SCSI result code into a blk_status_t value.
592 */
593static blk_status_t scsi_result_to_blk_status(int result)
594{
595 /*
596 * Check the scsi-ml byte first in case we converted a host or status
597 * byte.
598 */
599 switch (get_scsi_ml_byte(result)) {
600 case SCSIML_STAT_OK:
601 break;
602 case SCSIML_STAT_RESV_CONFLICT:
603 return BLK_STS_NEXUS;
604 case SCSIML_STAT_NOSPC:
605 return BLK_STS_NOSPC;
606 case SCSIML_STAT_MED_ERROR:
607 return BLK_STS_MEDIUM;
608 case SCSIML_STAT_TGT_FAILURE:
609 return BLK_STS_TARGET;
610 }
611
612 switch (host_byte(result)) {
613 case DID_OK:
614 if (scsi_status_is_good(result))
615 return BLK_STS_OK;
616 return BLK_STS_IOERR;
617 case DID_TRANSPORT_FAILFAST:
618 case DID_TRANSPORT_MARGINAL:
619 return BLK_STS_TRANSPORT;
620 default:
621 return BLK_STS_IOERR;
622 }
623}
624
625/**
626 * scsi_rq_err_bytes - determine number of bytes till the next failure boundary
627 * @rq: request to examine
628 *
629 * Description:
630 * A request could be merge of IOs which require different failure
631 * handling. This function determines the number of bytes which
632 * can be failed from the beginning of the request without
633 * crossing into area which need to be retried further.
634 *
635 * Return:
636 * The number of bytes to fail.
637 */
638static unsigned int scsi_rq_err_bytes(const struct request *rq)
639{
640 blk_opf_t ff = rq->cmd_flags & REQ_FAILFAST_MASK;
641 unsigned int bytes = 0;
642 struct bio *bio;
643
644 if (!(rq->rq_flags & RQF_MIXED_MERGE))
645 return blk_rq_bytes(rq);
646
647 /*
648 * Currently the only 'mixing' which can happen is between
649 * different fastfail types. We can safely fail portions
650 * which have all the failfast bits that the first one has -
651 * the ones which are at least as eager to fail as the first
652 * one.
653 */
654 for (bio = rq->bio; bio; bio = bio->bi_next) {
655 if ((bio->bi_opf & ff) != ff)
656 break;
657 bytes += bio->bi_iter.bi_size;
658 }
659
660 /* this could lead to infinite loop */
661 BUG_ON(blk_rq_bytes(rq) && !bytes);
662 return bytes;
663}
664
665static bool scsi_cmd_runtime_exceeced(struct scsi_cmnd *cmd)
666{
667 struct request *req = scsi_cmd_to_rq(cmd);
668 unsigned long wait_for;
669
670 if (cmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT)
671 return false;
672
673 wait_for = (cmd->allowed + 1) * req->timeout;
674 if (time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
675 scmd_printk(KERN_ERR, cmd, "timing out command, waited %lus\n",
676 wait_for/HZ);
677 return true;
678 }
679 return false;
680}
681
682/*
683 * When ALUA transition state is returned, reprep the cmd to
684 * use the ALUA handler's transition timeout. Delay the reprep
685 * 1 sec to avoid aggressive retries of the target in that
686 * state.
687 */
688#define ALUA_TRANSITION_REPREP_DELAY 1000
689
690/* Helper for scsi_io_completion() when special action required. */
691static void scsi_io_completion_action(struct scsi_cmnd *cmd, int result)
692{
693 struct request *req = scsi_cmd_to_rq(cmd);
694 int level = 0;
695 enum {ACTION_FAIL, ACTION_REPREP, ACTION_DELAYED_REPREP,
696 ACTION_RETRY, ACTION_DELAYED_RETRY} action;
697 struct scsi_sense_hdr sshdr;
698 bool sense_valid;
699 bool sense_current = true; /* false implies "deferred sense" */
700 blk_status_t blk_stat;
701
702 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
703 if (sense_valid)
704 sense_current = !scsi_sense_is_deferred(&sshdr);
705
706 blk_stat = scsi_result_to_blk_status(result);
707
708 if (host_byte(result) == DID_RESET) {
709 /* Third party bus reset or reset for error recovery
710 * reasons. Just retry the command and see what
711 * happens.
712 */
713 action = ACTION_RETRY;
714 } else if (sense_valid && sense_current) {
715 switch (sshdr.sense_key) {
716 case UNIT_ATTENTION:
717 if (cmd->device->removable) {
718 /* Detected disc change. Set a bit
719 * and quietly refuse further access.
720 */
721 cmd->device->changed = 1;
722 action = ACTION_FAIL;
723 } else {
724 /* Must have been a power glitch, or a
725 * bus reset. Could not have been a
726 * media change, so we just retry the
727 * command and see what happens.
728 */
729 action = ACTION_RETRY;
730 }
731 break;
732 case ILLEGAL_REQUEST:
733 /* If we had an ILLEGAL REQUEST returned, then
734 * we may have performed an unsupported
735 * command. The only thing this should be
736 * would be a ten byte read where only a six
737 * byte read was supported. Also, on a system
738 * where READ CAPACITY failed, we may have
739 * read past the end of the disk.
740 */
741 if ((cmd->device->use_10_for_rw &&
742 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
743 (cmd->cmnd[0] == READ_10 ||
744 cmd->cmnd[0] == WRITE_10)) {
745 /* This will issue a new 6-byte command. */
746 cmd->device->use_10_for_rw = 0;
747 action = ACTION_REPREP;
748 } else if (sshdr.asc == 0x10) /* DIX */ {
749 action = ACTION_FAIL;
750 blk_stat = BLK_STS_PROTECTION;
751 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
752 } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
753 action = ACTION_FAIL;
754 blk_stat = BLK_STS_TARGET;
755 } else
756 action = ACTION_FAIL;
757 break;
758 case ABORTED_COMMAND:
759 action = ACTION_FAIL;
760 if (sshdr.asc == 0x10) /* DIF */
761 blk_stat = BLK_STS_PROTECTION;
762 break;
763 case NOT_READY:
764 /* If the device is in the process of becoming
765 * ready, or has a temporary blockage, retry.
766 */
767 if (sshdr.asc == 0x04) {
768 switch (sshdr.ascq) {
769 case 0x01: /* becoming ready */
770 case 0x04: /* format in progress */
771 case 0x05: /* rebuild in progress */
772 case 0x06: /* recalculation in progress */
773 case 0x07: /* operation in progress */
774 case 0x08: /* Long write in progress */
775 case 0x09: /* self test in progress */
776 case 0x11: /* notify (enable spinup) required */
777 case 0x14: /* space allocation in progress */
778 case 0x1a: /* start stop unit in progress */
779 case 0x1b: /* sanitize in progress */
780 case 0x1d: /* configuration in progress */
781 case 0x24: /* depopulation in progress */
782 action = ACTION_DELAYED_RETRY;
783 break;
784 case 0x0a: /* ALUA state transition */
785 action = ACTION_DELAYED_REPREP;
786 break;
787 default:
788 action = ACTION_FAIL;
789 break;
790 }
791 } else
792 action = ACTION_FAIL;
793 break;
794 case VOLUME_OVERFLOW:
795 /* See SSC3rXX or current. */
796 action = ACTION_FAIL;
797 break;
798 case DATA_PROTECT:
799 action = ACTION_FAIL;
800 if ((sshdr.asc == 0x0C && sshdr.ascq == 0x12) ||
801 (sshdr.asc == 0x55 &&
802 (sshdr.ascq == 0x0E || sshdr.ascq == 0x0F))) {
803 /* Insufficient zone resources */
804 blk_stat = BLK_STS_ZONE_OPEN_RESOURCE;
805 }
806 break;
807 default:
808 action = ACTION_FAIL;
809 break;
810 }
811 } else
812 action = ACTION_FAIL;
813
814 if (action != ACTION_FAIL && scsi_cmd_runtime_exceeced(cmd))
815 action = ACTION_FAIL;
816
817 switch (action) {
818 case ACTION_FAIL:
819 /* Give up and fail the remainder of the request */
820 if (!(req->rq_flags & RQF_QUIET)) {
821 static DEFINE_RATELIMIT_STATE(_rs,
822 DEFAULT_RATELIMIT_INTERVAL,
823 DEFAULT_RATELIMIT_BURST);
824
825 if (unlikely(scsi_logging_level))
826 level =
827 SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
828 SCSI_LOG_MLCOMPLETE_BITS);
829
830 /*
831 * if logging is enabled the failure will be printed
832 * in scsi_log_completion(), so avoid duplicate messages
833 */
834 if (!level && __ratelimit(&_rs)) {
835 scsi_print_result(cmd, NULL, FAILED);
836 if (sense_valid)
837 scsi_print_sense(cmd);
838 scsi_print_command(cmd);
839 }
840 }
841 if (!scsi_end_request(req, blk_stat, scsi_rq_err_bytes(req)))
842 return;
843 fallthrough;
844 case ACTION_REPREP:
845 scsi_mq_requeue_cmd(cmd, 0);
846 break;
847 case ACTION_DELAYED_REPREP:
848 scsi_mq_requeue_cmd(cmd, ALUA_TRANSITION_REPREP_DELAY);
849 break;
850 case ACTION_RETRY:
851 /* Retry the same command immediately */
852 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, false);
853 break;
854 case ACTION_DELAYED_RETRY:
855 /* Retry the same command after a delay */
856 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, false);
857 break;
858 }
859}
860
861/*
862 * Helper for scsi_io_completion() when cmd->result is non-zero. Returns a
863 * new result that may suppress further error checking. Also modifies
864 * *blk_statp in some cases.
865 */
866static int scsi_io_completion_nz_result(struct scsi_cmnd *cmd, int result,
867 blk_status_t *blk_statp)
868{
869 bool sense_valid;
870 bool sense_current = true; /* false implies "deferred sense" */
871 struct request *req = scsi_cmd_to_rq(cmd);
872 struct scsi_sense_hdr sshdr;
873
874 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
875 if (sense_valid)
876 sense_current = !scsi_sense_is_deferred(&sshdr);
877
878 if (blk_rq_is_passthrough(req)) {
879 if (sense_valid) {
880 /*
881 * SG_IO wants current and deferred errors
882 */
883 cmd->sense_len = min(8 + cmd->sense_buffer[7],
884 SCSI_SENSE_BUFFERSIZE);
885 }
886 if (sense_current)
887 *blk_statp = scsi_result_to_blk_status(result);
888 } else if (blk_rq_bytes(req) == 0 && sense_current) {
889 /*
890 * Flush commands do not transfers any data, and thus cannot use
891 * good_bytes != blk_rq_bytes(req) as the signal for an error.
892 * This sets *blk_statp explicitly for the problem case.
893 */
894 *blk_statp = scsi_result_to_blk_status(result);
895 }
896 /*
897 * Recovered errors need reporting, but they're always treated as
898 * success, so fiddle the result code here. For passthrough requests
899 * we already took a copy of the original into sreq->result which
900 * is what gets returned to the user
901 */
902 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
903 bool do_print = true;
904 /*
905 * if ATA PASS-THROUGH INFORMATION AVAILABLE [0x0, 0x1d]
906 * skip print since caller wants ATA registers. Only occurs
907 * on SCSI ATA PASS_THROUGH commands when CK_COND=1
908 */
909 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
910 do_print = false;
911 else if (req->rq_flags & RQF_QUIET)
912 do_print = false;
913 if (do_print)
914 scsi_print_sense(cmd);
915 result = 0;
916 /* for passthrough, *blk_statp may be set */
917 *blk_statp = BLK_STS_OK;
918 }
919 /*
920 * Another corner case: the SCSI status byte is non-zero but 'good'.
921 * Example: PRE-FETCH command returns SAM_STAT_CONDITION_MET when
922 * it is able to fit nominated LBs in its cache (and SAM_STAT_GOOD
923 * if it can't fit). Treat SAM_STAT_CONDITION_MET and the related
924 * intermediate statuses (both obsolete in SAM-4) as good.
925 */
926 if ((result & 0xff) && scsi_status_is_good(result)) {
927 result = 0;
928 *blk_statp = BLK_STS_OK;
929 }
930 return result;
931}
932
933/**
934 * scsi_io_completion - Completion processing for SCSI commands.
935 * @cmd: command that is finished.
936 * @good_bytes: number of processed bytes.
937 *
938 * We will finish off the specified number of sectors. If we are done, the
939 * command block will be released and the queue function will be goosed. If we
940 * are not done then we have to figure out what to do next:
941 *
942 * a) We can call scsi_mq_requeue_cmd(). The request will be
943 * unprepared and put back on the queue. Then a new command will
944 * be created for it. This should be used if we made forward
945 * progress, or if we want to switch from READ(10) to READ(6) for
946 * example.
947 *
948 * b) We can call scsi_io_completion_action(). The request will be
949 * put back on the queue and retried using the same command as
950 * before, possibly after a delay.
951 *
952 * c) We can call scsi_end_request() with blk_stat other than
953 * BLK_STS_OK, to fail the remainder of the request.
954 */
955void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
956{
957 int result = cmd->result;
958 struct request *req = scsi_cmd_to_rq(cmd);
959 blk_status_t blk_stat = BLK_STS_OK;
960
961 if (unlikely(result)) /* a nz result may or may not be an error */
962 result = scsi_io_completion_nz_result(cmd, result, &blk_stat);
963
964 /*
965 * Next deal with any sectors which we were able to correctly
966 * handle.
967 */
968 SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd,
969 "%u sectors total, %d bytes done.\n",
970 blk_rq_sectors(req), good_bytes));
971
972 /*
973 * Failed, zero length commands always need to drop down
974 * to retry code. Fast path should return in this block.
975 */
976 if (likely(blk_rq_bytes(req) > 0 || blk_stat == BLK_STS_OK)) {
977 if (likely(!scsi_end_request(req, blk_stat, good_bytes)))
978 return; /* no bytes remaining */
979 }
980
981 /* Kill remainder if no retries. */
982 if (unlikely(blk_stat && scsi_noretry_cmd(cmd))) {
983 if (scsi_end_request(req, blk_stat, blk_rq_bytes(req)))
984 WARN_ONCE(true,
985 "Bytes remaining after failed, no-retry command");
986 return;
987 }
988
989 /*
990 * If there had been no error, but we have leftover bytes in the
991 * request just queue the command up again.
992 */
993 if (likely(result == 0))
994 scsi_mq_requeue_cmd(cmd, 0);
995 else
996 scsi_io_completion_action(cmd, result);
997}
998
999static inline bool scsi_cmd_needs_dma_drain(struct scsi_device *sdev,
1000 struct request *rq)
1001{
1002 return sdev->dma_drain_len && blk_rq_is_passthrough(rq) &&
1003 !op_is_write(req_op(rq)) &&
1004 sdev->host->hostt->dma_need_drain(rq);
1005}
1006
1007/**
1008 * scsi_alloc_sgtables - Allocate and initialize data and integrity scatterlists
1009 * @cmd: SCSI command data structure to initialize.
1010 *
1011 * Initializes @cmd->sdb and also @cmd->prot_sdb if data integrity is enabled
1012 * for @cmd.
1013 *
1014 * Returns:
1015 * * BLK_STS_OK - on success
1016 * * BLK_STS_RESOURCE - if the failure is retryable
1017 * * BLK_STS_IOERR - if the failure is fatal
1018 */
1019blk_status_t scsi_alloc_sgtables(struct scsi_cmnd *cmd)
1020{
1021 struct scsi_device *sdev = cmd->device;
1022 struct request *rq = scsi_cmd_to_rq(cmd);
1023 unsigned short nr_segs = blk_rq_nr_phys_segments(rq);
1024 struct scatterlist *last_sg = NULL;
1025 blk_status_t ret;
1026 bool need_drain = scsi_cmd_needs_dma_drain(sdev, rq);
1027 int count;
1028
1029 if (WARN_ON_ONCE(!nr_segs))
1030 return BLK_STS_IOERR;
1031
1032 /*
1033 * Make sure there is space for the drain. The driver must adjust
1034 * max_hw_segments to be prepared for this.
1035 */
1036 if (need_drain)
1037 nr_segs++;
1038
1039 /*
1040 * If sg table allocation fails, requeue request later.
1041 */
1042 if (unlikely(sg_alloc_table_chained(&cmd->sdb.table, nr_segs,
1043 cmd->sdb.table.sgl, SCSI_INLINE_SG_CNT)))
1044 return BLK_STS_RESOURCE;
1045
1046 /*
1047 * Next, walk the list, and fill in the addresses and sizes of
1048 * each segment.
1049 */
1050 count = __blk_rq_map_sg(rq->q, rq, cmd->sdb.table.sgl, &last_sg);
1051
1052 if (blk_rq_bytes(rq) & rq->q->dma_pad_mask) {
1053 unsigned int pad_len =
1054 (rq->q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1;
1055
1056 last_sg->length += pad_len;
1057 cmd->extra_len += pad_len;
1058 }
1059
1060 if (need_drain) {
1061 sg_unmark_end(last_sg);
1062 last_sg = sg_next(last_sg);
1063 sg_set_buf(last_sg, sdev->dma_drain_buf, sdev->dma_drain_len);
1064 sg_mark_end(last_sg);
1065
1066 cmd->extra_len += sdev->dma_drain_len;
1067 count++;
1068 }
1069
1070 BUG_ON(count > cmd->sdb.table.nents);
1071 cmd->sdb.table.nents = count;
1072 cmd->sdb.length = blk_rq_payload_bytes(rq);
1073
1074 if (blk_integrity_rq(rq)) {
1075 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1076 int ivecs;
1077
1078 if (WARN_ON_ONCE(!prot_sdb)) {
1079 /*
1080 * This can happen if someone (e.g. multipath)
1081 * queues a command to a device on an adapter
1082 * that does not support DIX.
1083 */
1084 ret = BLK_STS_IOERR;
1085 goto out_free_sgtables;
1086 }
1087
1088 ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
1089
1090 if (sg_alloc_table_chained(&prot_sdb->table, ivecs,
1091 prot_sdb->table.sgl,
1092 SCSI_INLINE_PROT_SG_CNT)) {
1093 ret = BLK_STS_RESOURCE;
1094 goto out_free_sgtables;
1095 }
1096
1097 count = blk_rq_map_integrity_sg(rq->q, rq->bio,
1098 prot_sdb->table.sgl);
1099 BUG_ON(count > ivecs);
1100 BUG_ON(count > queue_max_integrity_segments(rq->q));
1101
1102 cmd->prot_sdb = prot_sdb;
1103 cmd->prot_sdb->table.nents = count;
1104 }
1105
1106 return BLK_STS_OK;
1107out_free_sgtables:
1108 scsi_free_sgtables(cmd);
1109 return ret;
1110}
1111EXPORT_SYMBOL(scsi_alloc_sgtables);
1112
1113/**
1114 * scsi_initialize_rq - initialize struct scsi_cmnd partially
1115 * @rq: Request associated with the SCSI command to be initialized.
1116 *
1117 * This function initializes the members of struct scsi_cmnd that must be
1118 * initialized before request processing starts and that won't be
1119 * reinitialized if a SCSI command is requeued.
1120 */
1121static void scsi_initialize_rq(struct request *rq)
1122{
1123 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1124
1125 memset(cmd->cmnd, 0, sizeof(cmd->cmnd));
1126 cmd->cmd_len = MAX_COMMAND_SIZE;
1127 cmd->sense_len = 0;
1128 init_rcu_head(&cmd->rcu);
1129 cmd->jiffies_at_alloc = jiffies;
1130 cmd->retries = 0;
1131}
1132
1133struct request *scsi_alloc_request(struct request_queue *q, blk_opf_t opf,
1134 blk_mq_req_flags_t flags)
1135{
1136 struct request *rq;
1137
1138 rq = blk_mq_alloc_request(q, opf, flags);
1139 if (!IS_ERR(rq))
1140 scsi_initialize_rq(rq);
1141 return rq;
1142}
1143EXPORT_SYMBOL_GPL(scsi_alloc_request);
1144
1145/*
1146 * Only called when the request isn't completed by SCSI, and not freed by
1147 * SCSI
1148 */
1149static void scsi_cleanup_rq(struct request *rq)
1150{
1151 if (rq->rq_flags & RQF_DONTPREP) {
1152 scsi_mq_uninit_cmd(blk_mq_rq_to_pdu(rq));
1153 rq->rq_flags &= ~RQF_DONTPREP;
1154 }
1155}
1156
1157/* Called before a request is prepared. See also scsi_mq_prep_fn(). */
1158void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd)
1159{
1160 struct request *rq = scsi_cmd_to_rq(cmd);
1161
1162 if (!blk_rq_is_passthrough(rq) && !(cmd->flags & SCMD_INITIALIZED)) {
1163 cmd->flags |= SCMD_INITIALIZED;
1164 scsi_initialize_rq(rq);
1165 }
1166
1167 cmd->device = dev;
1168 INIT_LIST_HEAD(&cmd->eh_entry);
1169 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
1170}
1171
1172static blk_status_t scsi_setup_scsi_cmnd(struct scsi_device *sdev,
1173 struct request *req)
1174{
1175 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1176
1177 /*
1178 * Passthrough requests may transfer data, in which case they must
1179 * a bio attached to them. Or they might contain a SCSI command
1180 * that does not transfer data, in which case they may optionally
1181 * submit a request without an attached bio.
1182 */
1183 if (req->bio) {
1184 blk_status_t ret = scsi_alloc_sgtables(cmd);
1185 if (unlikely(ret != BLK_STS_OK))
1186 return ret;
1187 } else {
1188 BUG_ON(blk_rq_bytes(req));
1189
1190 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1191 }
1192
1193 cmd->transfersize = blk_rq_bytes(req);
1194 return BLK_STS_OK;
1195}
1196
1197static blk_status_t
1198scsi_device_state_check(struct scsi_device *sdev, struct request *req)
1199{
1200 switch (sdev->sdev_state) {
1201 case SDEV_CREATED:
1202 return BLK_STS_OK;
1203 case SDEV_OFFLINE:
1204 case SDEV_TRANSPORT_OFFLINE:
1205 /*
1206 * If the device is offline we refuse to process any
1207 * commands. The device must be brought online
1208 * before trying any recovery commands.
1209 */
1210 if (!sdev->offline_already) {
1211 sdev->offline_already = true;
1212 sdev_printk(KERN_ERR, sdev,
1213 "rejecting I/O to offline device\n");
1214 }
1215 return BLK_STS_IOERR;
1216 case SDEV_DEL:
1217 /*
1218 * If the device is fully deleted, we refuse to
1219 * process any commands as well.
1220 */
1221 sdev_printk(KERN_ERR, sdev,
1222 "rejecting I/O to dead device\n");
1223 return BLK_STS_IOERR;
1224 case SDEV_BLOCK:
1225 case SDEV_CREATED_BLOCK:
1226 return BLK_STS_RESOURCE;
1227 case SDEV_QUIESCE:
1228 /*
1229 * If the device is blocked we only accept power management
1230 * commands.
1231 */
1232 if (req && WARN_ON_ONCE(!(req->rq_flags & RQF_PM)))
1233 return BLK_STS_RESOURCE;
1234 return BLK_STS_OK;
1235 default:
1236 /*
1237 * For any other not fully online state we only allow
1238 * power management commands.
1239 */
1240 if (req && !(req->rq_flags & RQF_PM))
1241 return BLK_STS_OFFLINE;
1242 return BLK_STS_OK;
1243 }
1244}
1245
1246/*
1247 * scsi_dev_queue_ready: if we can send requests to sdev, assign one token
1248 * and return the token else return -1.
1249 */
1250static inline int scsi_dev_queue_ready(struct request_queue *q,
1251 struct scsi_device *sdev)
1252{
1253 int token;
1254
1255 token = sbitmap_get(&sdev->budget_map);
1256 if (atomic_read(&sdev->device_blocked)) {
1257 if (token < 0)
1258 goto out;
1259
1260 if (scsi_device_busy(sdev) > 1)
1261 goto out_dec;
1262
1263 /*
1264 * unblock after device_blocked iterates to zero
1265 */
1266 if (atomic_dec_return(&sdev->device_blocked) > 0)
1267 goto out_dec;
1268 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev,
1269 "unblocking device at zero depth\n"));
1270 }
1271
1272 return token;
1273out_dec:
1274 if (token >= 0)
1275 sbitmap_put(&sdev->budget_map, token);
1276out:
1277 return -1;
1278}
1279
1280/*
1281 * scsi_target_queue_ready: checks if there we can send commands to target
1282 * @sdev: scsi device on starget to check.
1283 */
1284static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1285 struct scsi_device *sdev)
1286{
1287 struct scsi_target *starget = scsi_target(sdev);
1288 unsigned int busy;
1289
1290 if (starget->single_lun) {
1291 spin_lock_irq(shost->host_lock);
1292 if (starget->starget_sdev_user &&
1293 starget->starget_sdev_user != sdev) {
1294 spin_unlock_irq(shost->host_lock);
1295 return 0;
1296 }
1297 starget->starget_sdev_user = sdev;
1298 spin_unlock_irq(shost->host_lock);
1299 }
1300
1301 if (starget->can_queue <= 0)
1302 return 1;
1303
1304 busy = atomic_inc_return(&starget->target_busy) - 1;
1305 if (atomic_read(&starget->target_blocked) > 0) {
1306 if (busy)
1307 goto starved;
1308
1309 /*
1310 * unblock after target_blocked iterates to zero
1311 */
1312 if (atomic_dec_return(&starget->target_blocked) > 0)
1313 goto out_dec;
1314
1315 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1316 "unblocking target at zero depth\n"));
1317 }
1318
1319 if (busy >= starget->can_queue)
1320 goto starved;
1321
1322 return 1;
1323
1324starved:
1325 spin_lock_irq(shost->host_lock);
1326 list_move_tail(&sdev->starved_entry, &shost->starved_list);
1327 spin_unlock_irq(shost->host_lock);
1328out_dec:
1329 if (starget->can_queue > 0)
1330 atomic_dec(&starget->target_busy);
1331 return 0;
1332}
1333
1334/*
1335 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1336 * return 0. We must end up running the queue again whenever 0 is
1337 * returned, else IO can hang.
1338 */
1339static inline int scsi_host_queue_ready(struct request_queue *q,
1340 struct Scsi_Host *shost,
1341 struct scsi_device *sdev,
1342 struct scsi_cmnd *cmd)
1343{
1344 if (atomic_read(&shost->host_blocked) > 0) {
1345 if (scsi_host_busy(shost) > 0)
1346 goto starved;
1347
1348 /*
1349 * unblock after host_blocked iterates to zero
1350 */
1351 if (atomic_dec_return(&shost->host_blocked) > 0)
1352 goto out_dec;
1353
1354 SCSI_LOG_MLQUEUE(3,
1355 shost_printk(KERN_INFO, shost,
1356 "unblocking host at zero depth\n"));
1357 }
1358
1359 if (shost->host_self_blocked)
1360 goto starved;
1361
1362 /* We're OK to process the command, so we can't be starved */
1363 if (!list_empty(&sdev->starved_entry)) {
1364 spin_lock_irq(shost->host_lock);
1365 if (!list_empty(&sdev->starved_entry))
1366 list_del_init(&sdev->starved_entry);
1367 spin_unlock_irq(shost->host_lock);
1368 }
1369
1370 __set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1371
1372 return 1;
1373
1374starved:
1375 spin_lock_irq(shost->host_lock);
1376 if (list_empty(&sdev->starved_entry))
1377 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1378 spin_unlock_irq(shost->host_lock);
1379out_dec:
1380 scsi_dec_host_busy(shost, cmd);
1381 return 0;
1382}
1383
1384/*
1385 * Busy state exporting function for request stacking drivers.
1386 *
1387 * For efficiency, no lock is taken to check the busy state of
1388 * shost/starget/sdev, since the returned value is not guaranteed and
1389 * may be changed after request stacking drivers call the function,
1390 * regardless of taking lock or not.
1391 *
1392 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1393 * needs to return 'not busy'. Otherwise, request stacking drivers
1394 * may hold requests forever.
1395 */
1396static bool scsi_mq_lld_busy(struct request_queue *q)
1397{
1398 struct scsi_device *sdev = q->queuedata;
1399 struct Scsi_Host *shost;
1400
1401 if (blk_queue_dying(q))
1402 return false;
1403
1404 shost = sdev->host;
1405
1406 /*
1407 * Ignore host/starget busy state.
1408 * Since block layer does not have a concept of fairness across
1409 * multiple queues, congestion of host/starget needs to be handled
1410 * in SCSI layer.
1411 */
1412 if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
1413 return true;
1414
1415 return false;
1416}
1417
1418/*
1419 * Block layer request completion callback. May be called from interrupt
1420 * context.
1421 */
1422static void scsi_complete(struct request *rq)
1423{
1424 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1425 enum scsi_disposition disposition;
1426
1427 INIT_LIST_HEAD(&cmd->eh_entry);
1428
1429 atomic_inc(&cmd->device->iodone_cnt);
1430 if (cmd->result)
1431 atomic_inc(&cmd->device->ioerr_cnt);
1432
1433 disposition = scsi_decide_disposition(cmd);
1434 if (disposition != SUCCESS && scsi_cmd_runtime_exceeced(cmd))
1435 disposition = SUCCESS;
1436
1437 scsi_log_completion(cmd, disposition);
1438
1439 switch (disposition) {
1440 case SUCCESS:
1441 scsi_finish_command(cmd);
1442 break;
1443 case NEEDS_RETRY:
1444 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
1445 break;
1446 case ADD_TO_MLQUEUE:
1447 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1448 break;
1449 default:
1450 scsi_eh_scmd_add(cmd);
1451 break;
1452 }
1453}
1454
1455/**
1456 * scsi_dispatch_cmd - Dispatch a command to the low-level driver.
1457 * @cmd: command block we are dispatching.
1458 *
1459 * Return: nonzero return request was rejected and device's queue needs to be
1460 * plugged.
1461 */
1462static int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
1463{
1464 struct Scsi_Host *host = cmd->device->host;
1465 int rtn = 0;
1466
1467 /* check if the device is still usable */
1468 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
1469 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
1470 * returns an immediate error upwards, and signals
1471 * that the device is no longer present */
1472 cmd->result = DID_NO_CONNECT << 16;
1473 goto done;
1474 }
1475
1476 /* Check to see if the scsi lld made this device blocked. */
1477 if (unlikely(scsi_device_blocked(cmd->device))) {
1478 /*
1479 * in blocked state, the command is just put back on
1480 * the device queue. The suspend state has already
1481 * blocked the queue so future requests should not
1482 * occur until the device transitions out of the
1483 * suspend state.
1484 */
1485 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1486 "queuecommand : device blocked\n"));
1487 return SCSI_MLQUEUE_DEVICE_BUSY;
1488 }
1489
1490 /* Store the LUN value in cmnd, if needed. */
1491 if (cmd->device->lun_in_cdb)
1492 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
1493 (cmd->device->lun << 5 & 0xe0);
1494
1495 scsi_log_send(cmd);
1496
1497 /*
1498 * Before we queue this command, check if the command
1499 * length exceeds what the host adapter can handle.
1500 */
1501 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
1502 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1503 "queuecommand : command too long. "
1504 "cdb_size=%d host->max_cmd_len=%d\n",
1505 cmd->cmd_len, cmd->device->host->max_cmd_len));
1506 cmd->result = (DID_ABORT << 16);
1507 goto done;
1508 }
1509
1510 if (unlikely(host->shost_state == SHOST_DEL)) {
1511 cmd->result = (DID_NO_CONNECT << 16);
1512 goto done;
1513
1514 }
1515
1516 trace_scsi_dispatch_cmd_start(cmd);
1517 rtn = host->hostt->queuecommand(host, cmd);
1518 if (rtn) {
1519 trace_scsi_dispatch_cmd_error(cmd, rtn);
1520 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
1521 rtn != SCSI_MLQUEUE_TARGET_BUSY)
1522 rtn = SCSI_MLQUEUE_HOST_BUSY;
1523
1524 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1525 "queuecommand : request rejected\n"));
1526 }
1527
1528 return rtn;
1529 done:
1530 scsi_done(cmd);
1531 return 0;
1532}
1533
1534/* Size in bytes of the sg-list stored in the scsi-mq command-private data. */
1535static unsigned int scsi_mq_inline_sgl_size(struct Scsi_Host *shost)
1536{
1537 return min_t(unsigned int, shost->sg_tablesize, SCSI_INLINE_SG_CNT) *
1538 sizeof(struct scatterlist);
1539}
1540
1541static blk_status_t scsi_prepare_cmd(struct request *req)
1542{
1543 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1544 struct scsi_device *sdev = req->q->queuedata;
1545 struct Scsi_Host *shost = sdev->host;
1546 bool in_flight = test_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1547 struct scatterlist *sg;
1548
1549 scsi_init_command(sdev, cmd);
1550
1551 cmd->eh_eflags = 0;
1552 cmd->prot_type = 0;
1553 cmd->prot_flags = 0;
1554 cmd->submitter = 0;
1555 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1556 cmd->underflow = 0;
1557 cmd->transfersize = 0;
1558 cmd->host_scribble = NULL;
1559 cmd->result = 0;
1560 cmd->extra_len = 0;
1561 cmd->state = 0;
1562 if (in_flight)
1563 __set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1564
1565 /*
1566 * Only clear the driver-private command data if the LLD does not supply
1567 * a function to initialize that data.
1568 */
1569 if (!shost->hostt->init_cmd_priv)
1570 memset(cmd + 1, 0, shost->hostt->cmd_size);
1571
1572 cmd->prot_op = SCSI_PROT_NORMAL;
1573 if (blk_rq_bytes(req))
1574 cmd->sc_data_direction = rq_dma_dir(req);
1575 else
1576 cmd->sc_data_direction = DMA_NONE;
1577
1578 sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
1579 cmd->sdb.table.sgl = sg;
1580
1581 if (scsi_host_get_prot(shost)) {
1582 memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer));
1583
1584 cmd->prot_sdb->table.sgl =
1585 (struct scatterlist *)(cmd->prot_sdb + 1);
1586 }
1587
1588 /*
1589 * Special handling for passthrough commands, which don't go to the ULP
1590 * at all:
1591 */
1592 if (blk_rq_is_passthrough(req))
1593 return scsi_setup_scsi_cmnd(sdev, req);
1594
1595 if (sdev->handler && sdev->handler->prep_fn) {
1596 blk_status_t ret = sdev->handler->prep_fn(sdev, req);
1597
1598 if (ret != BLK_STS_OK)
1599 return ret;
1600 }
1601
1602 /* Usually overridden by the ULP */
1603 cmd->allowed = 0;
1604 memset(cmd->cmnd, 0, sizeof(cmd->cmnd));
1605 return scsi_cmd_to_driver(cmd)->init_command(cmd);
1606}
1607
1608static void scsi_done_internal(struct scsi_cmnd *cmd, bool complete_directly)
1609{
1610 struct request *req = scsi_cmd_to_rq(cmd);
1611
1612 switch (cmd->submitter) {
1613 case SUBMITTED_BY_BLOCK_LAYER:
1614 break;
1615 case SUBMITTED_BY_SCSI_ERROR_HANDLER:
1616 return scsi_eh_done(cmd);
1617 case SUBMITTED_BY_SCSI_RESET_IOCTL:
1618 return;
1619 }
1620
1621 if (unlikely(blk_should_fake_timeout(scsi_cmd_to_rq(cmd)->q)))
1622 return;
1623 if (unlikely(test_and_set_bit(SCMD_STATE_COMPLETE, &cmd->state)))
1624 return;
1625 trace_scsi_dispatch_cmd_done(cmd);
1626
1627 if (complete_directly)
1628 blk_mq_complete_request_direct(req, scsi_complete);
1629 else
1630 blk_mq_complete_request(req);
1631}
1632
1633void scsi_done(struct scsi_cmnd *cmd)
1634{
1635 scsi_done_internal(cmd, false);
1636}
1637EXPORT_SYMBOL(scsi_done);
1638
1639void scsi_done_direct(struct scsi_cmnd *cmd)
1640{
1641 scsi_done_internal(cmd, true);
1642}
1643EXPORT_SYMBOL(scsi_done_direct);
1644
1645static void scsi_mq_put_budget(struct request_queue *q, int budget_token)
1646{
1647 struct scsi_device *sdev = q->queuedata;
1648
1649 sbitmap_put(&sdev->budget_map, budget_token);
1650}
1651
1652/*
1653 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
1654 * not change behaviour from the previous unplug mechanism, experimentation
1655 * may prove this needs changing.
1656 */
1657#define SCSI_QUEUE_DELAY 3
1658
1659static int scsi_mq_get_budget(struct request_queue *q)
1660{
1661 struct scsi_device *sdev = q->queuedata;
1662 int token = scsi_dev_queue_ready(q, sdev);
1663
1664 if (token >= 0)
1665 return token;
1666
1667 atomic_inc(&sdev->restarts);
1668
1669 /*
1670 * Orders atomic_inc(&sdev->restarts) and atomic_read(&sdev->device_busy).
1671 * .restarts must be incremented before .device_busy is read because the
1672 * code in scsi_run_queue_async() depends on the order of these operations.
1673 */
1674 smp_mb__after_atomic();
1675
1676 /*
1677 * If all in-flight requests originated from this LUN are completed
1678 * before reading .device_busy, sdev->device_busy will be observed as
1679 * zero, then blk_mq_delay_run_hw_queues() will dispatch this request
1680 * soon. Otherwise, completion of one of these requests will observe
1681 * the .restarts flag, and the request queue will be run for handling
1682 * this request, see scsi_end_request().
1683 */
1684 if (unlikely(scsi_device_busy(sdev) == 0 &&
1685 !scsi_device_blocked(sdev)))
1686 blk_mq_delay_run_hw_queues(sdev->request_queue, SCSI_QUEUE_DELAY);
1687 return -1;
1688}
1689
1690static void scsi_mq_set_rq_budget_token(struct request *req, int token)
1691{
1692 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1693
1694 cmd->budget_token = token;
1695}
1696
1697static int scsi_mq_get_rq_budget_token(struct request *req)
1698{
1699 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1700
1701 return cmd->budget_token;
1702}
1703
1704static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
1705 const struct blk_mq_queue_data *bd)
1706{
1707 struct request *req = bd->rq;
1708 struct request_queue *q = req->q;
1709 struct scsi_device *sdev = q->queuedata;
1710 struct Scsi_Host *shost = sdev->host;
1711 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1712 blk_status_t ret;
1713 int reason;
1714
1715 WARN_ON_ONCE(cmd->budget_token < 0);
1716
1717 /*
1718 * If the device is not in running state we will reject some or all
1719 * commands.
1720 */
1721 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
1722 ret = scsi_device_state_check(sdev, req);
1723 if (ret != BLK_STS_OK)
1724 goto out_put_budget;
1725 }
1726
1727 ret = BLK_STS_RESOURCE;
1728 if (!scsi_target_queue_ready(shost, sdev))
1729 goto out_put_budget;
1730 if (unlikely(scsi_host_in_recovery(shost))) {
1731 if (cmd->flags & SCMD_FAIL_IF_RECOVERING)
1732 ret = BLK_STS_OFFLINE;
1733 goto out_dec_target_busy;
1734 }
1735 if (!scsi_host_queue_ready(q, shost, sdev, cmd))
1736 goto out_dec_target_busy;
1737
1738 if (!(req->rq_flags & RQF_DONTPREP)) {
1739 ret = scsi_prepare_cmd(req);
1740 if (ret != BLK_STS_OK)
1741 goto out_dec_host_busy;
1742 req->rq_flags |= RQF_DONTPREP;
1743 } else {
1744 clear_bit(SCMD_STATE_COMPLETE, &cmd->state);
1745 }
1746
1747 cmd->flags &= SCMD_PRESERVED_FLAGS;
1748 if (sdev->simple_tags)
1749 cmd->flags |= SCMD_TAGGED;
1750 if (bd->last)
1751 cmd->flags |= SCMD_LAST;
1752
1753 scsi_set_resid(cmd, 0);
1754 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
1755 cmd->submitter = SUBMITTED_BY_BLOCK_LAYER;
1756
1757 blk_mq_start_request(req);
1758 reason = scsi_dispatch_cmd(cmd);
1759 if (reason) {
1760 scsi_set_blocked(cmd, reason);
1761 ret = BLK_STS_RESOURCE;
1762 goto out_dec_host_busy;
1763 }
1764
1765 atomic_inc(&cmd->device->iorequest_cnt);
1766 return BLK_STS_OK;
1767
1768out_dec_host_busy:
1769 scsi_dec_host_busy(shost, cmd);
1770out_dec_target_busy:
1771 if (scsi_target(sdev)->can_queue > 0)
1772 atomic_dec(&scsi_target(sdev)->target_busy);
1773out_put_budget:
1774 scsi_mq_put_budget(q, cmd->budget_token);
1775 cmd->budget_token = -1;
1776 switch (ret) {
1777 case BLK_STS_OK:
1778 break;
1779 case BLK_STS_RESOURCE:
1780 case BLK_STS_ZONE_RESOURCE:
1781 if (scsi_device_blocked(sdev))
1782 ret = BLK_STS_DEV_RESOURCE;
1783 break;
1784 case BLK_STS_AGAIN:
1785 cmd->result = DID_BUS_BUSY << 16;
1786 if (req->rq_flags & RQF_DONTPREP)
1787 scsi_mq_uninit_cmd(cmd);
1788 break;
1789 default:
1790 if (unlikely(!scsi_device_online(sdev)))
1791 cmd->result = DID_NO_CONNECT << 16;
1792 else
1793 cmd->result = DID_ERROR << 16;
1794 /*
1795 * Make sure to release all allocated resources when
1796 * we hit an error, as we will never see this command
1797 * again.
1798 */
1799 if (req->rq_flags & RQF_DONTPREP)
1800 scsi_mq_uninit_cmd(cmd);
1801 scsi_run_queue_async(sdev);
1802 break;
1803 }
1804 return ret;
1805}
1806
1807static int scsi_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
1808 unsigned int hctx_idx, unsigned int numa_node)
1809{
1810 struct Scsi_Host *shost = set->driver_data;
1811 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1812 struct scatterlist *sg;
1813 int ret = 0;
1814
1815 cmd->sense_buffer =
1816 kmem_cache_alloc_node(scsi_sense_cache, GFP_KERNEL, numa_node);
1817 if (!cmd->sense_buffer)
1818 return -ENOMEM;
1819
1820 if (scsi_host_get_prot(shost)) {
1821 sg = (void *)cmd + sizeof(struct scsi_cmnd) +
1822 shost->hostt->cmd_size;
1823 cmd->prot_sdb = (void *)sg + scsi_mq_inline_sgl_size(shost);
1824 }
1825
1826 if (shost->hostt->init_cmd_priv) {
1827 ret = shost->hostt->init_cmd_priv(shost, cmd);
1828 if (ret < 0)
1829 kmem_cache_free(scsi_sense_cache, cmd->sense_buffer);
1830 }
1831
1832 return ret;
1833}
1834
1835static void scsi_mq_exit_request(struct blk_mq_tag_set *set, struct request *rq,
1836 unsigned int hctx_idx)
1837{
1838 struct Scsi_Host *shost = set->driver_data;
1839 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1840
1841 if (shost->hostt->exit_cmd_priv)
1842 shost->hostt->exit_cmd_priv(shost, cmd);
1843 kmem_cache_free(scsi_sense_cache, cmd->sense_buffer);
1844}
1845
1846
1847static int scsi_mq_poll(struct blk_mq_hw_ctx *hctx, struct io_comp_batch *iob)
1848{
1849 struct Scsi_Host *shost = hctx->driver_data;
1850
1851 if (shost->hostt->mq_poll)
1852 return shost->hostt->mq_poll(shost, hctx->queue_num);
1853
1854 return 0;
1855}
1856
1857static int scsi_init_hctx(struct blk_mq_hw_ctx *hctx, void *data,
1858 unsigned int hctx_idx)
1859{
1860 struct Scsi_Host *shost = data;
1861
1862 hctx->driver_data = shost;
1863 return 0;
1864}
1865
1866static void scsi_map_queues(struct blk_mq_tag_set *set)
1867{
1868 struct Scsi_Host *shost = container_of(set, struct Scsi_Host, tag_set);
1869
1870 if (shost->hostt->map_queues)
1871 return shost->hostt->map_queues(shost);
1872 blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]);
1873}
1874
1875void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
1876{
1877 struct device *dev = shost->dma_dev;
1878
1879 /*
1880 * this limit is imposed by hardware restrictions
1881 */
1882 blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
1883 SG_MAX_SEGMENTS));
1884
1885 if (scsi_host_prot_dma(shost)) {
1886 shost->sg_prot_tablesize =
1887 min_not_zero(shost->sg_prot_tablesize,
1888 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
1889 BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
1890 blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
1891 }
1892
1893 blk_queue_max_hw_sectors(q, shost->max_sectors);
1894 blk_queue_segment_boundary(q, shost->dma_boundary);
1895 dma_set_seg_boundary(dev, shost->dma_boundary);
1896
1897 blk_queue_max_segment_size(q, shost->max_segment_size);
1898 blk_queue_virt_boundary(q, shost->virt_boundary_mask);
1899 dma_set_max_seg_size(dev, queue_max_segment_size(q));
1900
1901 /*
1902 * Set a reasonable default alignment: The larger of 32-byte (dword),
1903 * which is a common minimum for HBAs, and the minimum DMA alignment,
1904 * which is set by the platform.
1905 *
1906 * Devices that require a bigger alignment can increase it later.
1907 */
1908 blk_queue_dma_alignment(q, max(4, dma_get_cache_alignment()) - 1);
1909}
1910EXPORT_SYMBOL_GPL(__scsi_init_queue);
1911
1912static const struct blk_mq_ops scsi_mq_ops_no_commit = {
1913 .get_budget = scsi_mq_get_budget,
1914 .put_budget = scsi_mq_put_budget,
1915 .queue_rq = scsi_queue_rq,
1916 .complete = scsi_complete,
1917 .timeout = scsi_timeout,
1918#ifdef CONFIG_BLK_DEBUG_FS
1919 .show_rq = scsi_show_rq,
1920#endif
1921 .init_request = scsi_mq_init_request,
1922 .exit_request = scsi_mq_exit_request,
1923 .cleanup_rq = scsi_cleanup_rq,
1924 .busy = scsi_mq_lld_busy,
1925 .map_queues = scsi_map_queues,
1926 .init_hctx = scsi_init_hctx,
1927 .poll = scsi_mq_poll,
1928 .set_rq_budget_token = scsi_mq_set_rq_budget_token,
1929 .get_rq_budget_token = scsi_mq_get_rq_budget_token,
1930};
1931
1932
1933static void scsi_commit_rqs(struct blk_mq_hw_ctx *hctx)
1934{
1935 struct Scsi_Host *shost = hctx->driver_data;
1936
1937 shost->hostt->commit_rqs(shost, hctx->queue_num);
1938}
1939
1940static const struct blk_mq_ops scsi_mq_ops = {
1941 .get_budget = scsi_mq_get_budget,
1942 .put_budget = scsi_mq_put_budget,
1943 .queue_rq = scsi_queue_rq,
1944 .commit_rqs = scsi_commit_rqs,
1945 .complete = scsi_complete,
1946 .timeout = scsi_timeout,
1947#ifdef CONFIG_BLK_DEBUG_FS
1948 .show_rq = scsi_show_rq,
1949#endif
1950 .init_request = scsi_mq_init_request,
1951 .exit_request = scsi_mq_exit_request,
1952 .cleanup_rq = scsi_cleanup_rq,
1953 .busy = scsi_mq_lld_busy,
1954 .map_queues = scsi_map_queues,
1955 .init_hctx = scsi_init_hctx,
1956 .poll = scsi_mq_poll,
1957 .set_rq_budget_token = scsi_mq_set_rq_budget_token,
1958 .get_rq_budget_token = scsi_mq_get_rq_budget_token,
1959};
1960
1961int scsi_mq_setup_tags(struct Scsi_Host *shost)
1962{
1963 unsigned int cmd_size, sgl_size;
1964 struct blk_mq_tag_set *tag_set = &shost->tag_set;
1965
1966 sgl_size = max_t(unsigned int, sizeof(struct scatterlist),
1967 scsi_mq_inline_sgl_size(shost));
1968 cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size;
1969 if (scsi_host_get_prot(shost))
1970 cmd_size += sizeof(struct scsi_data_buffer) +
1971 sizeof(struct scatterlist) * SCSI_INLINE_PROT_SG_CNT;
1972
1973 memset(tag_set, 0, sizeof(*tag_set));
1974 if (shost->hostt->commit_rqs)
1975 tag_set->ops = &scsi_mq_ops;
1976 else
1977 tag_set->ops = &scsi_mq_ops_no_commit;
1978 tag_set->nr_hw_queues = shost->nr_hw_queues ? : 1;
1979 tag_set->nr_maps = shost->nr_maps ? : 1;
1980 tag_set->queue_depth = shost->can_queue;
1981 tag_set->cmd_size = cmd_size;
1982 tag_set->numa_node = dev_to_node(shost->dma_dev);
1983 tag_set->flags = BLK_MQ_F_SHOULD_MERGE;
1984 tag_set->flags |=
1985 BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
1986 tag_set->driver_data = shost;
1987 if (shost->host_tagset)
1988 tag_set->flags |= BLK_MQ_F_TAG_HCTX_SHARED;
1989
1990 return blk_mq_alloc_tag_set(tag_set);
1991}
1992
1993void scsi_mq_free_tags(struct kref *kref)
1994{
1995 struct Scsi_Host *shost = container_of(kref, typeof(*shost),
1996 tagset_refcnt);
1997
1998 blk_mq_free_tag_set(&shost->tag_set);
1999 complete(&shost->tagset_freed);
2000}
2001
2002/**
2003 * scsi_device_from_queue - return sdev associated with a request_queue
2004 * @q: The request queue to return the sdev from
2005 *
2006 * Return the sdev associated with a request queue or NULL if the
2007 * request_queue does not reference a SCSI device.
2008 */
2009struct scsi_device *scsi_device_from_queue(struct request_queue *q)
2010{
2011 struct scsi_device *sdev = NULL;
2012
2013 if (q->mq_ops == &scsi_mq_ops_no_commit ||
2014 q->mq_ops == &scsi_mq_ops)
2015 sdev = q->queuedata;
2016 if (!sdev || !get_device(&sdev->sdev_gendev))
2017 sdev = NULL;
2018
2019 return sdev;
2020}
2021/*
2022 * pktcdvd should have been integrated into the SCSI layers, but for historical
2023 * reasons like the old IDE driver it isn't. This export allows it to safely
2024 * probe if a given device is a SCSI one and only attach to that.
2025 */
2026#ifdef CONFIG_CDROM_PKTCDVD_MODULE
2027EXPORT_SYMBOL_GPL(scsi_device_from_queue);
2028#endif
2029
2030/**
2031 * scsi_block_requests - Utility function used by low-level drivers to prevent
2032 * further commands from being queued to the device.
2033 * @shost: host in question
2034 *
2035 * There is no timer nor any other means by which the requests get unblocked
2036 * other than the low-level driver calling scsi_unblock_requests().
2037 */
2038void scsi_block_requests(struct Scsi_Host *shost)
2039{
2040 shost->host_self_blocked = 1;
2041}
2042EXPORT_SYMBOL(scsi_block_requests);
2043
2044/**
2045 * scsi_unblock_requests - Utility function used by low-level drivers to allow
2046 * further commands to be queued to the device.
2047 * @shost: host in question
2048 *
2049 * There is no timer nor any other means by which the requests get unblocked
2050 * other than the low-level driver calling scsi_unblock_requests(). This is done
2051 * as an API function so that changes to the internals of the scsi mid-layer
2052 * won't require wholesale changes to drivers that use this feature.
2053 */
2054void scsi_unblock_requests(struct Scsi_Host *shost)
2055{
2056 shost->host_self_blocked = 0;
2057 scsi_run_host_queues(shost);
2058}
2059EXPORT_SYMBOL(scsi_unblock_requests);
2060
2061void scsi_exit_queue(void)
2062{
2063 kmem_cache_destroy(scsi_sense_cache);
2064}
2065
2066/**
2067 * scsi_mode_select - issue a mode select
2068 * @sdev: SCSI device to be queried
2069 * @pf: Page format bit (1 == standard, 0 == vendor specific)
2070 * @sp: Save page bit (0 == don't save, 1 == save)
2071 * @buffer: request buffer (may not be smaller than eight bytes)
2072 * @len: length of request buffer.
2073 * @timeout: command timeout
2074 * @retries: number of retries before failing
2075 * @data: returns a structure abstracting the mode header data
2076 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2077 * must be SCSI_SENSE_BUFFERSIZE big.
2078 *
2079 * Returns zero if successful; negative error number or scsi
2080 * status on error
2081 *
2082 */
2083int scsi_mode_select(struct scsi_device *sdev, int pf, int sp,
2084 unsigned char *buffer, int len, int timeout, int retries,
2085 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2086{
2087 unsigned char cmd[10];
2088 unsigned char *real_buffer;
2089 int ret;
2090
2091 memset(cmd, 0, sizeof(cmd));
2092 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
2093
2094 /*
2095 * Use MODE SELECT(10) if the device asked for it or if the mode page
2096 * and the mode select header cannot fit within the maximumm 255 bytes
2097 * of the MODE SELECT(6) command.
2098 */
2099 if (sdev->use_10_for_ms ||
2100 len + 4 > 255 ||
2101 data->block_descriptor_length > 255) {
2102 if (len > 65535 - 8)
2103 return -EINVAL;
2104 real_buffer = kmalloc(8 + len, GFP_KERNEL);
2105 if (!real_buffer)
2106 return -ENOMEM;
2107 memcpy(real_buffer + 8, buffer, len);
2108 len += 8;
2109 real_buffer[0] = 0;
2110 real_buffer[1] = 0;
2111 real_buffer[2] = data->medium_type;
2112 real_buffer[3] = data->device_specific;
2113 real_buffer[4] = data->longlba ? 0x01 : 0;
2114 real_buffer[5] = 0;
2115 put_unaligned_be16(data->block_descriptor_length,
2116 &real_buffer[6]);
2117
2118 cmd[0] = MODE_SELECT_10;
2119 put_unaligned_be16(len, &cmd[7]);
2120 } else {
2121 if (data->longlba)
2122 return -EINVAL;
2123
2124 real_buffer = kmalloc(4 + len, GFP_KERNEL);
2125 if (!real_buffer)
2126 return -ENOMEM;
2127 memcpy(real_buffer + 4, buffer, len);
2128 len += 4;
2129 real_buffer[0] = 0;
2130 real_buffer[1] = data->medium_type;
2131 real_buffer[2] = data->device_specific;
2132 real_buffer[3] = data->block_descriptor_length;
2133
2134 cmd[0] = MODE_SELECT;
2135 cmd[4] = len;
2136 }
2137
2138 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
2139 sshdr, timeout, retries, NULL);
2140 kfree(real_buffer);
2141 return ret;
2142}
2143EXPORT_SYMBOL_GPL(scsi_mode_select);
2144
2145/**
2146 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
2147 * @sdev: SCSI device to be queried
2148 * @dbd: set to prevent mode sense from returning block descriptors
2149 * @modepage: mode page being requested
2150 * @buffer: request buffer (may not be smaller than eight bytes)
2151 * @len: length of request buffer.
2152 * @timeout: command timeout
2153 * @retries: number of retries before failing
2154 * @data: returns a structure abstracting the mode header data
2155 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2156 * must be SCSI_SENSE_BUFFERSIZE big.
2157 *
2158 * Returns zero if successful, or a negative error number on failure
2159 */
2160int
2161scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
2162 unsigned char *buffer, int len, int timeout, int retries,
2163 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2164{
2165 unsigned char cmd[12];
2166 int use_10_for_ms;
2167 int header_length;
2168 int result, retry_count = retries;
2169 struct scsi_sense_hdr my_sshdr;
2170
2171 memset(data, 0, sizeof(*data));
2172 memset(&cmd[0], 0, 12);
2173
2174 dbd = sdev->set_dbd_for_ms ? 8 : dbd;
2175 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
2176 cmd[2] = modepage;
2177
2178 /* caller might not be interested in sense, but we need it */
2179 if (!sshdr)
2180 sshdr = &my_sshdr;
2181
2182 retry:
2183 use_10_for_ms = sdev->use_10_for_ms || len > 255;
2184
2185 if (use_10_for_ms) {
2186 if (len < 8 || len > 65535)
2187 return -EINVAL;
2188
2189 cmd[0] = MODE_SENSE_10;
2190 put_unaligned_be16(len, &cmd[7]);
2191 header_length = 8;
2192 } else {
2193 if (len < 4)
2194 return -EINVAL;
2195
2196 cmd[0] = MODE_SENSE;
2197 cmd[4] = len;
2198 header_length = 4;
2199 }
2200
2201 memset(buffer, 0, len);
2202
2203 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
2204 sshdr, timeout, retries, NULL);
2205 if (result < 0)
2206 return result;
2207
2208 /* This code looks awful: what it's doing is making sure an
2209 * ILLEGAL REQUEST sense return identifies the actual command
2210 * byte as the problem. MODE_SENSE commands can return
2211 * ILLEGAL REQUEST if the code page isn't supported */
2212
2213 if (!scsi_status_is_good(result)) {
2214 if (scsi_sense_valid(sshdr)) {
2215 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
2216 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
2217 /*
2218 * Invalid command operation code: retry using
2219 * MODE SENSE(6) if this was a MODE SENSE(10)
2220 * request, except if the request mode page is
2221 * too large for MODE SENSE single byte
2222 * allocation length field.
2223 */
2224 if (use_10_for_ms) {
2225 if (len > 255)
2226 return -EIO;
2227 sdev->use_10_for_ms = 0;
2228 goto retry;
2229 }
2230 }
2231 if (scsi_status_is_check_condition(result) &&
2232 sshdr->sense_key == UNIT_ATTENTION &&
2233 retry_count) {
2234 retry_count--;
2235 goto retry;
2236 }
2237 }
2238 return -EIO;
2239 }
2240 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
2241 (modepage == 6 || modepage == 8))) {
2242 /* Initio breakage? */
2243 header_length = 0;
2244 data->length = 13;
2245 data->medium_type = 0;
2246 data->device_specific = 0;
2247 data->longlba = 0;
2248 data->block_descriptor_length = 0;
2249 } else if (use_10_for_ms) {
2250 data->length = get_unaligned_be16(&buffer[0]) + 2;
2251 data->medium_type = buffer[2];
2252 data->device_specific = buffer[3];
2253 data->longlba = buffer[4] & 0x01;
2254 data->block_descriptor_length = get_unaligned_be16(&buffer[6]);
2255 } else {
2256 data->length = buffer[0] + 1;
2257 data->medium_type = buffer[1];
2258 data->device_specific = buffer[2];
2259 data->block_descriptor_length = buffer[3];
2260 }
2261 data->header_length = header_length;
2262
2263 return 0;
2264}
2265EXPORT_SYMBOL(scsi_mode_sense);
2266
2267/**
2268 * scsi_test_unit_ready - test if unit is ready
2269 * @sdev: scsi device to change the state of.
2270 * @timeout: command timeout
2271 * @retries: number of retries before failing
2272 * @sshdr: outpout pointer for decoded sense information.
2273 *
2274 * Returns zero if unsuccessful or an error if TUR failed. For
2275 * removable media, UNIT_ATTENTION sets ->changed flag.
2276 **/
2277int
2278scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2279 struct scsi_sense_hdr *sshdr)
2280{
2281 char cmd[] = {
2282 TEST_UNIT_READY, 0, 0, 0, 0, 0,
2283 };
2284 int result;
2285
2286 /* try to eat the UNIT_ATTENTION if there are enough retries */
2287 do {
2288 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
2289 timeout, 1, NULL);
2290 if (sdev->removable && scsi_sense_valid(sshdr) &&
2291 sshdr->sense_key == UNIT_ATTENTION)
2292 sdev->changed = 1;
2293 } while (scsi_sense_valid(sshdr) &&
2294 sshdr->sense_key == UNIT_ATTENTION && --retries);
2295
2296 return result;
2297}
2298EXPORT_SYMBOL(scsi_test_unit_ready);
2299
2300/**
2301 * scsi_device_set_state - Take the given device through the device state model.
2302 * @sdev: scsi device to change the state of.
2303 * @state: state to change to.
2304 *
2305 * Returns zero if successful or an error if the requested
2306 * transition is illegal.
2307 */
2308int
2309scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2310{
2311 enum scsi_device_state oldstate = sdev->sdev_state;
2312
2313 if (state == oldstate)
2314 return 0;
2315
2316 switch (state) {
2317 case SDEV_CREATED:
2318 switch (oldstate) {
2319 case SDEV_CREATED_BLOCK:
2320 break;
2321 default:
2322 goto illegal;
2323 }
2324 break;
2325
2326 case SDEV_RUNNING:
2327 switch (oldstate) {
2328 case SDEV_CREATED:
2329 case SDEV_OFFLINE:
2330 case SDEV_TRANSPORT_OFFLINE:
2331 case SDEV_QUIESCE:
2332 case SDEV_BLOCK:
2333 break;
2334 default:
2335 goto illegal;
2336 }
2337 break;
2338
2339 case SDEV_QUIESCE:
2340 switch (oldstate) {
2341 case SDEV_RUNNING:
2342 case SDEV_OFFLINE:
2343 case SDEV_TRANSPORT_OFFLINE:
2344 break;
2345 default:
2346 goto illegal;
2347 }
2348 break;
2349
2350 case SDEV_OFFLINE:
2351 case SDEV_TRANSPORT_OFFLINE:
2352 switch (oldstate) {
2353 case SDEV_CREATED:
2354 case SDEV_RUNNING:
2355 case SDEV_QUIESCE:
2356 case SDEV_BLOCK:
2357 break;
2358 default:
2359 goto illegal;
2360 }
2361 break;
2362
2363 case SDEV_BLOCK:
2364 switch (oldstate) {
2365 case SDEV_RUNNING:
2366 case SDEV_CREATED_BLOCK:
2367 case SDEV_QUIESCE:
2368 case SDEV_OFFLINE:
2369 break;
2370 default:
2371 goto illegal;
2372 }
2373 break;
2374
2375 case SDEV_CREATED_BLOCK:
2376 switch (oldstate) {
2377 case SDEV_CREATED:
2378 break;
2379 default:
2380 goto illegal;
2381 }
2382 break;
2383
2384 case SDEV_CANCEL:
2385 switch (oldstate) {
2386 case SDEV_CREATED:
2387 case SDEV_RUNNING:
2388 case SDEV_QUIESCE:
2389 case SDEV_OFFLINE:
2390 case SDEV_TRANSPORT_OFFLINE:
2391 break;
2392 default:
2393 goto illegal;
2394 }
2395 break;
2396
2397 case SDEV_DEL:
2398 switch (oldstate) {
2399 case SDEV_CREATED:
2400 case SDEV_RUNNING:
2401 case SDEV_OFFLINE:
2402 case SDEV_TRANSPORT_OFFLINE:
2403 case SDEV_CANCEL:
2404 case SDEV_BLOCK:
2405 case SDEV_CREATED_BLOCK:
2406 break;
2407 default:
2408 goto illegal;
2409 }
2410 break;
2411
2412 }
2413 sdev->offline_already = false;
2414 sdev->sdev_state = state;
2415 return 0;
2416
2417 illegal:
2418 SCSI_LOG_ERROR_RECOVERY(1,
2419 sdev_printk(KERN_ERR, sdev,
2420 "Illegal state transition %s->%s",
2421 scsi_device_state_name(oldstate),
2422 scsi_device_state_name(state))
2423 );
2424 return -EINVAL;
2425}
2426EXPORT_SYMBOL(scsi_device_set_state);
2427
2428/**
2429 * scsi_evt_emit - emit a single SCSI device uevent
2430 * @sdev: associated SCSI device
2431 * @evt: event to emit
2432 *
2433 * Send a single uevent (scsi_event) to the associated scsi_device.
2434 */
2435static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2436{
2437 int idx = 0;
2438 char *envp[3];
2439
2440 switch (evt->evt_type) {
2441 case SDEV_EVT_MEDIA_CHANGE:
2442 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2443 break;
2444 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2445 scsi_rescan_device(&sdev->sdev_gendev);
2446 envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2447 break;
2448 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2449 envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2450 break;
2451 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2452 envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2453 break;
2454 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2455 envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2456 break;
2457 case SDEV_EVT_LUN_CHANGE_REPORTED:
2458 envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2459 break;
2460 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2461 envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
2462 break;
2463 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2464 envp[idx++] = "SDEV_UA=POWER_ON_RESET_OCCURRED";
2465 break;
2466 default:
2467 /* do nothing */
2468 break;
2469 }
2470
2471 envp[idx++] = NULL;
2472
2473 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2474}
2475
2476/**
2477 * scsi_evt_thread - send a uevent for each scsi event
2478 * @work: work struct for scsi_device
2479 *
2480 * Dispatch queued events to their associated scsi_device kobjects
2481 * as uevents.
2482 */
2483void scsi_evt_thread(struct work_struct *work)
2484{
2485 struct scsi_device *sdev;
2486 enum scsi_device_event evt_type;
2487 LIST_HEAD(event_list);
2488
2489 sdev = container_of(work, struct scsi_device, event_work);
2490
2491 for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
2492 if (test_and_clear_bit(evt_type, sdev->pending_events))
2493 sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
2494
2495 while (1) {
2496 struct scsi_event *evt;
2497 struct list_head *this, *tmp;
2498 unsigned long flags;
2499
2500 spin_lock_irqsave(&sdev->list_lock, flags);
2501 list_splice_init(&sdev->event_list, &event_list);
2502 spin_unlock_irqrestore(&sdev->list_lock, flags);
2503
2504 if (list_empty(&event_list))
2505 break;
2506
2507 list_for_each_safe(this, tmp, &event_list) {
2508 evt = list_entry(this, struct scsi_event, node);
2509 list_del(&evt->node);
2510 scsi_evt_emit(sdev, evt);
2511 kfree(evt);
2512 }
2513 }
2514}
2515
2516/**
2517 * sdev_evt_send - send asserted event to uevent thread
2518 * @sdev: scsi_device event occurred on
2519 * @evt: event to send
2520 *
2521 * Assert scsi device event asynchronously.
2522 */
2523void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2524{
2525 unsigned long flags;
2526
2527#if 0
2528 /* FIXME: currently this check eliminates all media change events
2529 * for polled devices. Need to update to discriminate between AN
2530 * and polled events */
2531 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2532 kfree(evt);
2533 return;
2534 }
2535#endif
2536
2537 spin_lock_irqsave(&sdev->list_lock, flags);
2538 list_add_tail(&evt->node, &sdev->event_list);
2539 schedule_work(&sdev->event_work);
2540 spin_unlock_irqrestore(&sdev->list_lock, flags);
2541}
2542EXPORT_SYMBOL_GPL(sdev_evt_send);
2543
2544/**
2545 * sdev_evt_alloc - allocate a new scsi event
2546 * @evt_type: type of event to allocate
2547 * @gfpflags: GFP flags for allocation
2548 *
2549 * Allocates and returns a new scsi_event.
2550 */
2551struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2552 gfp_t gfpflags)
2553{
2554 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2555 if (!evt)
2556 return NULL;
2557
2558 evt->evt_type = evt_type;
2559 INIT_LIST_HEAD(&evt->node);
2560
2561 /* evt_type-specific initialization, if any */
2562 switch (evt_type) {
2563 case SDEV_EVT_MEDIA_CHANGE:
2564 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2565 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2566 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2567 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2568 case SDEV_EVT_LUN_CHANGE_REPORTED:
2569 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2570 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2571 default:
2572 /* do nothing */
2573 break;
2574 }
2575
2576 return evt;
2577}
2578EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2579
2580/**
2581 * sdev_evt_send_simple - send asserted event to uevent thread
2582 * @sdev: scsi_device event occurred on
2583 * @evt_type: type of event to send
2584 * @gfpflags: GFP flags for allocation
2585 *
2586 * Assert scsi device event asynchronously, given an event type.
2587 */
2588void sdev_evt_send_simple(struct scsi_device *sdev,
2589 enum scsi_device_event evt_type, gfp_t gfpflags)
2590{
2591 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2592 if (!evt) {
2593 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2594 evt_type);
2595 return;
2596 }
2597
2598 sdev_evt_send(sdev, evt);
2599}
2600EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2601
2602/**
2603 * scsi_device_quiesce - Block all commands except power management.
2604 * @sdev: scsi device to quiesce.
2605 *
2606 * This works by trying to transition to the SDEV_QUIESCE state
2607 * (which must be a legal transition). When the device is in this
2608 * state, only power management requests will be accepted, all others will
2609 * be deferred.
2610 *
2611 * Must be called with user context, may sleep.
2612 *
2613 * Returns zero if unsuccessful or an error if not.
2614 */
2615int
2616scsi_device_quiesce(struct scsi_device *sdev)
2617{
2618 struct request_queue *q = sdev->request_queue;
2619 int err;
2620
2621 /*
2622 * It is allowed to call scsi_device_quiesce() multiple times from
2623 * the same context but concurrent scsi_device_quiesce() calls are
2624 * not allowed.
2625 */
2626 WARN_ON_ONCE(sdev->quiesced_by && sdev->quiesced_by != current);
2627
2628 if (sdev->quiesced_by == current)
2629 return 0;
2630
2631 blk_set_pm_only(q);
2632
2633 blk_mq_freeze_queue(q);
2634 /*
2635 * Ensure that the effect of blk_set_pm_only() will be visible
2636 * for percpu_ref_tryget() callers that occur after the queue
2637 * unfreeze even if the queue was already frozen before this function
2638 * was called. See also https://lwn.net/Articles/573497/.
2639 */
2640 synchronize_rcu();
2641 blk_mq_unfreeze_queue(q);
2642
2643 mutex_lock(&sdev->state_mutex);
2644 err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2645 if (err == 0)
2646 sdev->quiesced_by = current;
2647 else
2648 blk_clear_pm_only(q);
2649 mutex_unlock(&sdev->state_mutex);
2650
2651 return err;
2652}
2653EXPORT_SYMBOL(scsi_device_quiesce);
2654
2655/**
2656 * scsi_device_resume - Restart user issued commands to a quiesced device.
2657 * @sdev: scsi device to resume.
2658 *
2659 * Moves the device from quiesced back to running and restarts the
2660 * queues.
2661 *
2662 * Must be called with user context, may sleep.
2663 */
2664void scsi_device_resume(struct scsi_device *sdev)
2665{
2666 /* check if the device state was mutated prior to resume, and if
2667 * so assume the state is being managed elsewhere (for example
2668 * device deleted during suspend)
2669 */
2670 mutex_lock(&sdev->state_mutex);
2671 if (sdev->sdev_state == SDEV_QUIESCE)
2672 scsi_device_set_state(sdev, SDEV_RUNNING);
2673 if (sdev->quiesced_by) {
2674 sdev->quiesced_by = NULL;
2675 blk_clear_pm_only(sdev->request_queue);
2676 }
2677 mutex_unlock(&sdev->state_mutex);
2678}
2679EXPORT_SYMBOL(scsi_device_resume);
2680
2681static void
2682device_quiesce_fn(struct scsi_device *sdev, void *data)
2683{
2684 scsi_device_quiesce(sdev);
2685}
2686
2687void
2688scsi_target_quiesce(struct scsi_target *starget)
2689{
2690 starget_for_each_device(starget, NULL, device_quiesce_fn);
2691}
2692EXPORT_SYMBOL(scsi_target_quiesce);
2693
2694static void
2695device_resume_fn(struct scsi_device *sdev, void *data)
2696{
2697 scsi_device_resume(sdev);
2698}
2699
2700void
2701scsi_target_resume(struct scsi_target *starget)
2702{
2703 starget_for_each_device(starget, NULL, device_resume_fn);
2704}
2705EXPORT_SYMBOL(scsi_target_resume);
2706
2707static int __scsi_internal_device_block_nowait(struct scsi_device *sdev)
2708{
2709 if (scsi_device_set_state(sdev, SDEV_BLOCK))
2710 return scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2711
2712 return 0;
2713}
2714
2715void scsi_start_queue(struct scsi_device *sdev)
2716{
2717 if (cmpxchg(&sdev->queue_stopped, 1, 0))
2718 blk_mq_unquiesce_queue(sdev->request_queue);
2719}
2720
2721static void scsi_stop_queue(struct scsi_device *sdev, bool nowait)
2722{
2723 /*
2724 * The atomic variable of ->queue_stopped covers that
2725 * blk_mq_quiesce_queue* is balanced with blk_mq_unquiesce_queue.
2726 *
2727 * However, we still need to wait until quiesce is done
2728 * in case that queue has been stopped.
2729 */
2730 if (!cmpxchg(&sdev->queue_stopped, 0, 1)) {
2731 if (nowait)
2732 blk_mq_quiesce_queue_nowait(sdev->request_queue);
2733 else
2734 blk_mq_quiesce_queue(sdev->request_queue);
2735 } else {
2736 if (!nowait)
2737 blk_mq_wait_quiesce_done(sdev->request_queue->tag_set);
2738 }
2739}
2740
2741/**
2742 * scsi_internal_device_block_nowait - try to transition to the SDEV_BLOCK state
2743 * @sdev: device to block
2744 *
2745 * Pause SCSI command processing on the specified device. Does not sleep.
2746 *
2747 * Returns zero if successful or a negative error code upon failure.
2748 *
2749 * Notes:
2750 * This routine transitions the device to the SDEV_BLOCK state (which must be
2751 * a legal transition). When the device is in this state, command processing
2752 * is paused until the device leaves the SDEV_BLOCK state. See also
2753 * scsi_internal_device_unblock_nowait().
2754 */
2755int scsi_internal_device_block_nowait(struct scsi_device *sdev)
2756{
2757 int ret = __scsi_internal_device_block_nowait(sdev);
2758
2759 /*
2760 * The device has transitioned to SDEV_BLOCK. Stop the
2761 * block layer from calling the midlayer with this device's
2762 * request queue.
2763 */
2764 if (!ret)
2765 scsi_stop_queue(sdev, true);
2766 return ret;
2767}
2768EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait);
2769
2770/**
2771 * scsi_internal_device_block - try to transition to the SDEV_BLOCK state
2772 * @sdev: device to block
2773 *
2774 * Pause SCSI command processing on the specified device and wait until all
2775 * ongoing scsi_request_fn() / scsi_queue_rq() calls have finished. May sleep.
2776 *
2777 * Returns zero if successful or a negative error code upon failure.
2778 *
2779 * Note:
2780 * This routine transitions the device to the SDEV_BLOCK state (which must be
2781 * a legal transition). When the device is in this state, command processing
2782 * is paused until the device leaves the SDEV_BLOCK state. See also
2783 * scsi_internal_device_unblock().
2784 */
2785static int scsi_internal_device_block(struct scsi_device *sdev)
2786{
2787 int err;
2788
2789 mutex_lock(&sdev->state_mutex);
2790 err = __scsi_internal_device_block_nowait(sdev);
2791 if (err == 0)
2792 scsi_stop_queue(sdev, false);
2793 mutex_unlock(&sdev->state_mutex);
2794
2795 return err;
2796}
2797
2798/**
2799 * scsi_internal_device_unblock_nowait - resume a device after a block request
2800 * @sdev: device to resume
2801 * @new_state: state to set the device to after unblocking
2802 *
2803 * Restart the device queue for a previously suspended SCSI device. Does not
2804 * sleep.
2805 *
2806 * Returns zero if successful or a negative error code upon failure.
2807 *
2808 * Notes:
2809 * This routine transitions the device to the SDEV_RUNNING state or to one of
2810 * the offline states (which must be a legal transition) allowing the midlayer
2811 * to goose the queue for this device.
2812 */
2813int scsi_internal_device_unblock_nowait(struct scsi_device *sdev,
2814 enum scsi_device_state new_state)
2815{
2816 switch (new_state) {
2817 case SDEV_RUNNING:
2818 case SDEV_TRANSPORT_OFFLINE:
2819 break;
2820 default:
2821 return -EINVAL;
2822 }
2823
2824 /*
2825 * Try to transition the scsi device to SDEV_RUNNING or one of the
2826 * offlined states and goose the device queue if successful.
2827 */
2828 switch (sdev->sdev_state) {
2829 case SDEV_BLOCK:
2830 case SDEV_TRANSPORT_OFFLINE:
2831 sdev->sdev_state = new_state;
2832 break;
2833 case SDEV_CREATED_BLOCK:
2834 if (new_state == SDEV_TRANSPORT_OFFLINE ||
2835 new_state == SDEV_OFFLINE)
2836 sdev->sdev_state = new_state;
2837 else
2838 sdev->sdev_state = SDEV_CREATED;
2839 break;
2840 case SDEV_CANCEL:
2841 case SDEV_OFFLINE:
2842 break;
2843 default:
2844 return -EINVAL;
2845 }
2846 scsi_start_queue(sdev);
2847
2848 return 0;
2849}
2850EXPORT_SYMBOL_GPL(scsi_internal_device_unblock_nowait);
2851
2852/**
2853 * scsi_internal_device_unblock - resume a device after a block request
2854 * @sdev: device to resume
2855 * @new_state: state to set the device to after unblocking
2856 *
2857 * Restart the device queue for a previously suspended SCSI device. May sleep.
2858 *
2859 * Returns zero if successful or a negative error code upon failure.
2860 *
2861 * Notes:
2862 * This routine transitions the device to the SDEV_RUNNING state or to one of
2863 * the offline states (which must be a legal transition) allowing the midlayer
2864 * to goose the queue for this device.
2865 */
2866static int scsi_internal_device_unblock(struct scsi_device *sdev,
2867 enum scsi_device_state new_state)
2868{
2869 int ret;
2870
2871 mutex_lock(&sdev->state_mutex);
2872 ret = scsi_internal_device_unblock_nowait(sdev, new_state);
2873 mutex_unlock(&sdev->state_mutex);
2874
2875 return ret;
2876}
2877
2878static void
2879device_block(struct scsi_device *sdev, void *data)
2880{
2881 int ret;
2882
2883 ret = scsi_internal_device_block(sdev);
2884
2885 WARN_ONCE(ret, "scsi_internal_device_block(%s) failed: ret = %d\n",
2886 dev_name(&sdev->sdev_gendev), ret);
2887}
2888
2889static int
2890target_block(struct device *dev, void *data)
2891{
2892 if (scsi_is_target_device(dev))
2893 starget_for_each_device(to_scsi_target(dev), NULL,
2894 device_block);
2895 return 0;
2896}
2897
2898void
2899scsi_target_block(struct device *dev)
2900{
2901 if (scsi_is_target_device(dev))
2902 starget_for_each_device(to_scsi_target(dev), NULL,
2903 device_block);
2904 else
2905 device_for_each_child(dev, NULL, target_block);
2906}
2907EXPORT_SYMBOL_GPL(scsi_target_block);
2908
2909static void
2910device_unblock(struct scsi_device *sdev, void *data)
2911{
2912 scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
2913}
2914
2915static int
2916target_unblock(struct device *dev, void *data)
2917{
2918 if (scsi_is_target_device(dev))
2919 starget_for_each_device(to_scsi_target(dev), data,
2920 device_unblock);
2921 return 0;
2922}
2923
2924void
2925scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
2926{
2927 if (scsi_is_target_device(dev))
2928 starget_for_each_device(to_scsi_target(dev), &new_state,
2929 device_unblock);
2930 else
2931 device_for_each_child(dev, &new_state, target_unblock);
2932}
2933EXPORT_SYMBOL_GPL(scsi_target_unblock);
2934
2935int
2936scsi_host_block(struct Scsi_Host *shost)
2937{
2938 struct scsi_device *sdev;
2939 int ret = 0;
2940
2941 /*
2942 * Call scsi_internal_device_block_nowait so we can avoid
2943 * calling synchronize_rcu() for each LUN.
2944 */
2945 shost_for_each_device(sdev, shost) {
2946 mutex_lock(&sdev->state_mutex);
2947 ret = scsi_internal_device_block_nowait(sdev);
2948 mutex_unlock(&sdev->state_mutex);
2949 if (ret) {
2950 scsi_device_put(sdev);
2951 break;
2952 }
2953 }
2954
2955 /*
2956 * SCSI never enables blk-mq's BLK_MQ_F_BLOCKING flag so
2957 * calling synchronize_rcu() once is enough.
2958 */
2959 WARN_ON_ONCE(shost->tag_set.flags & BLK_MQ_F_BLOCKING);
2960
2961 if (!ret)
2962 synchronize_rcu();
2963
2964 return ret;
2965}
2966EXPORT_SYMBOL_GPL(scsi_host_block);
2967
2968int
2969scsi_host_unblock(struct Scsi_Host *shost, int new_state)
2970{
2971 struct scsi_device *sdev;
2972 int ret = 0;
2973
2974 shost_for_each_device(sdev, shost) {
2975 ret = scsi_internal_device_unblock(sdev, new_state);
2976 if (ret) {
2977 scsi_device_put(sdev);
2978 break;
2979 }
2980 }
2981 return ret;
2982}
2983EXPORT_SYMBOL_GPL(scsi_host_unblock);
2984
2985/**
2986 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
2987 * @sgl: scatter-gather list
2988 * @sg_count: number of segments in sg
2989 * @offset: offset in bytes into sg, on return offset into the mapped area
2990 * @len: bytes to map, on return number of bytes mapped
2991 *
2992 * Returns virtual address of the start of the mapped page
2993 */
2994void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
2995 size_t *offset, size_t *len)
2996{
2997 int i;
2998 size_t sg_len = 0, len_complete = 0;
2999 struct scatterlist *sg;
3000 struct page *page;
3001
3002 WARN_ON(!irqs_disabled());
3003
3004 for_each_sg(sgl, sg, sg_count, i) {
3005 len_complete = sg_len; /* Complete sg-entries */
3006 sg_len += sg->length;
3007 if (sg_len > *offset)
3008 break;
3009 }
3010
3011 if (unlikely(i == sg_count)) {
3012 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
3013 "elements %d\n",
3014 __func__, sg_len, *offset, sg_count);
3015 WARN_ON(1);
3016 return NULL;
3017 }
3018
3019 /* Offset starting from the beginning of first page in this sg-entry */
3020 *offset = *offset - len_complete + sg->offset;
3021
3022 /* Assumption: contiguous pages can be accessed as "page + i" */
3023 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
3024 *offset &= ~PAGE_MASK;
3025
3026 /* Bytes in this sg-entry from *offset to the end of the page */
3027 sg_len = PAGE_SIZE - *offset;
3028 if (*len > sg_len)
3029 *len = sg_len;
3030
3031 return kmap_atomic(page);
3032}
3033EXPORT_SYMBOL(scsi_kmap_atomic_sg);
3034
3035/**
3036 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
3037 * @virt: virtual address to be unmapped
3038 */
3039void scsi_kunmap_atomic_sg(void *virt)
3040{
3041 kunmap_atomic(virt);
3042}
3043EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
3044
3045void sdev_disable_disk_events(struct scsi_device *sdev)
3046{
3047 atomic_inc(&sdev->disk_events_disable_depth);
3048}
3049EXPORT_SYMBOL(sdev_disable_disk_events);
3050
3051void sdev_enable_disk_events(struct scsi_device *sdev)
3052{
3053 if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0))
3054 return;
3055 atomic_dec(&sdev->disk_events_disable_depth);
3056}
3057EXPORT_SYMBOL(sdev_enable_disk_events);
3058
3059static unsigned char designator_prio(const unsigned char *d)
3060{
3061 if (d[1] & 0x30)
3062 /* not associated with LUN */
3063 return 0;
3064
3065 if (d[3] == 0)
3066 /* invalid length */
3067 return 0;
3068
3069 /*
3070 * Order of preference for lun descriptor:
3071 * - SCSI name string
3072 * - NAA IEEE Registered Extended
3073 * - EUI-64 based 16-byte
3074 * - EUI-64 based 12-byte
3075 * - NAA IEEE Registered
3076 * - NAA IEEE Extended
3077 * - EUI-64 based 8-byte
3078 * - SCSI name string (truncated)
3079 * - T10 Vendor ID
3080 * as longer descriptors reduce the likelyhood
3081 * of identification clashes.
3082 */
3083
3084 switch (d[1] & 0xf) {
3085 case 8:
3086 /* SCSI name string, variable-length UTF-8 */
3087 return 9;
3088 case 3:
3089 switch (d[4] >> 4) {
3090 case 6:
3091 /* NAA registered extended */
3092 return 8;
3093 case 5:
3094 /* NAA registered */
3095 return 5;
3096 case 4:
3097 /* NAA extended */
3098 return 4;
3099 case 3:
3100 /* NAA locally assigned */
3101 return 1;
3102 default:
3103 break;
3104 }
3105 break;
3106 case 2:
3107 switch (d[3]) {
3108 case 16:
3109 /* EUI64-based, 16 byte */
3110 return 7;
3111 case 12:
3112 /* EUI64-based, 12 byte */
3113 return 6;
3114 case 8:
3115 /* EUI64-based, 8 byte */
3116 return 3;
3117 default:
3118 break;
3119 }
3120 break;
3121 case 1:
3122 /* T10 vendor ID */
3123 return 1;
3124 default:
3125 break;
3126 }
3127
3128 return 0;
3129}
3130
3131/**
3132 * scsi_vpd_lun_id - return a unique device identification
3133 * @sdev: SCSI device
3134 * @id: buffer for the identification
3135 * @id_len: length of the buffer
3136 *
3137 * Copies a unique device identification into @id based
3138 * on the information in the VPD page 0x83 of the device.
3139 * The string will be formatted as a SCSI name string.
3140 *
3141 * Returns the length of the identification or error on failure.
3142 * If the identifier is longer than the supplied buffer the actual
3143 * identifier length is returned and the buffer is not zero-padded.
3144 */
3145int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len)
3146{
3147 u8 cur_id_prio = 0;
3148 u8 cur_id_size = 0;
3149 const unsigned char *d, *cur_id_str;
3150 const struct scsi_vpd *vpd_pg83;
3151 int id_size = -EINVAL;
3152
3153 rcu_read_lock();
3154 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3155 if (!vpd_pg83) {
3156 rcu_read_unlock();
3157 return -ENXIO;
3158 }
3159
3160 /* The id string must be at least 20 bytes + terminating NULL byte */
3161 if (id_len < 21) {
3162 rcu_read_unlock();
3163 return -EINVAL;
3164 }
3165
3166 memset(id, 0, id_len);
3167 for (d = vpd_pg83->data + 4;
3168 d < vpd_pg83->data + vpd_pg83->len;
3169 d += d[3] + 4) {
3170 u8 prio = designator_prio(d);
3171
3172 if (prio == 0 || cur_id_prio > prio)
3173 continue;
3174
3175 switch (d[1] & 0xf) {
3176 case 0x1:
3177 /* T10 Vendor ID */
3178 if (cur_id_size > d[3])
3179 break;
3180 cur_id_prio = prio;
3181 cur_id_size = d[3];
3182 if (cur_id_size + 4 > id_len)
3183 cur_id_size = id_len - 4;
3184 cur_id_str = d + 4;
3185 id_size = snprintf(id, id_len, "t10.%*pE",
3186 cur_id_size, cur_id_str);
3187 break;
3188 case 0x2:
3189 /* EUI-64 */
3190 cur_id_prio = prio;
3191 cur_id_size = d[3];
3192 cur_id_str = d + 4;
3193 switch (cur_id_size) {
3194 case 8:
3195 id_size = snprintf(id, id_len,
3196 "eui.%8phN",
3197 cur_id_str);
3198 break;
3199 case 12:
3200 id_size = snprintf(id, id_len,
3201 "eui.%12phN",
3202 cur_id_str);
3203 break;
3204 case 16:
3205 id_size = snprintf(id, id_len,
3206 "eui.%16phN",
3207 cur_id_str);
3208 break;
3209 default:
3210 break;
3211 }
3212 break;
3213 case 0x3:
3214 /* NAA */
3215 cur_id_prio = prio;
3216 cur_id_size = d[3];
3217 cur_id_str = d + 4;
3218 switch (cur_id_size) {
3219 case 8:
3220 id_size = snprintf(id, id_len,
3221 "naa.%8phN",
3222 cur_id_str);
3223 break;
3224 case 16:
3225 id_size = snprintf(id, id_len,
3226 "naa.%16phN",
3227 cur_id_str);
3228 break;
3229 default:
3230 break;
3231 }
3232 break;
3233 case 0x8:
3234 /* SCSI name string */
3235 if (cur_id_size > d[3])
3236 break;
3237 /* Prefer others for truncated descriptor */
3238 if (d[3] > id_len) {
3239 prio = 2;
3240 if (cur_id_prio > prio)
3241 break;
3242 }
3243 cur_id_prio = prio;
3244 cur_id_size = id_size = d[3];
3245 cur_id_str = d + 4;
3246 if (cur_id_size >= id_len)
3247 cur_id_size = id_len - 1;
3248 memcpy(id, cur_id_str, cur_id_size);
3249 break;
3250 default:
3251 break;
3252 }
3253 }
3254 rcu_read_unlock();
3255
3256 return id_size;
3257}
3258EXPORT_SYMBOL(scsi_vpd_lun_id);
3259
3260/*
3261 * scsi_vpd_tpg_id - return a target port group identifier
3262 * @sdev: SCSI device
3263 *
3264 * Returns the Target Port Group identifier from the information
3265 * froom VPD page 0x83 of the device.
3266 *
3267 * Returns the identifier or error on failure.
3268 */
3269int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id)
3270{
3271 const unsigned char *d;
3272 const struct scsi_vpd *vpd_pg83;
3273 int group_id = -EAGAIN, rel_port = -1;
3274
3275 rcu_read_lock();
3276 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3277 if (!vpd_pg83) {
3278 rcu_read_unlock();
3279 return -ENXIO;
3280 }
3281
3282 d = vpd_pg83->data + 4;
3283 while (d < vpd_pg83->data + vpd_pg83->len) {
3284 switch (d[1] & 0xf) {
3285 case 0x4:
3286 /* Relative target port */
3287 rel_port = get_unaligned_be16(&d[6]);
3288 break;
3289 case 0x5:
3290 /* Target port group */
3291 group_id = get_unaligned_be16(&d[6]);
3292 break;
3293 default:
3294 break;
3295 }
3296 d += d[3] + 4;
3297 }
3298 rcu_read_unlock();
3299
3300 if (group_id >= 0 && rel_id && rel_port != -1)
3301 *rel_id = rel_port;
3302
3303 return group_id;
3304}
3305EXPORT_SYMBOL(scsi_vpd_tpg_id);
3306
3307/**
3308 * scsi_build_sense - build sense data for a command
3309 * @scmd: scsi command for which the sense should be formatted
3310 * @desc: Sense format (non-zero == descriptor format,
3311 * 0 == fixed format)
3312 * @key: Sense key
3313 * @asc: Additional sense code
3314 * @ascq: Additional sense code qualifier
3315 *
3316 **/
3317void scsi_build_sense(struct scsi_cmnd *scmd, int desc, u8 key, u8 asc, u8 ascq)
3318{
3319 scsi_build_sense_buffer(desc, scmd->sense_buffer, key, asc, ascq);
3320 scmd->result = SAM_STAT_CHECK_CONDITION;
3321}
3322EXPORT_SYMBOL_GPL(scsi_build_sense);