Loading...
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
187/**
188 * scsi_execute_cmd - insert request and wait for the result
189 * @sdev: scsi_device
190 * @cmd: scsi command
191 * @opf: block layer request cmd_flags
192 * @buffer: data buffer
193 * @bufflen: len of buffer
194 * @timeout: request timeout in HZ
195 * @retries: number of times to retry request
196 * @args: Optional args. See struct definition for field descriptions
197 *
198 * Returns the scsi_cmnd result field if a command was executed, or a negative
199 * Linux error code if we didn't get that far.
200 */
201int scsi_execute_cmd(struct scsi_device *sdev, const unsigned char *cmd,
202 blk_opf_t opf, void *buffer, unsigned int bufflen,
203 int timeout, int retries,
204 const struct scsi_exec_args *args)
205{
206 static const struct scsi_exec_args default_args;
207 struct request *req;
208 struct scsi_cmnd *scmd;
209 int ret;
210
211 if (!args)
212 args = &default_args;
213 else if (WARN_ON_ONCE(args->sense &&
214 args->sense_len != SCSI_SENSE_BUFFERSIZE))
215 return -EINVAL;
216
217 req = scsi_alloc_request(sdev->request_queue, opf, args->req_flags);
218 if (IS_ERR(req))
219 return PTR_ERR(req);
220
221 if (bufflen) {
222 ret = blk_rq_map_kern(sdev->request_queue, req,
223 buffer, bufflen, GFP_NOIO);
224 if (ret)
225 goto out;
226 }
227 scmd = blk_mq_rq_to_pdu(req);
228 scmd->cmd_len = COMMAND_SIZE(cmd[0]);
229 memcpy(scmd->cmnd, cmd, scmd->cmd_len);
230 scmd->allowed = retries;
231 scmd->flags |= args->scmd_flags;
232 req->timeout = timeout;
233 req->rq_flags |= RQF_QUIET;
234
235 /*
236 * head injection *required* here otherwise quiesce won't work
237 */
238 blk_execute_rq(req, true);
239
240 /*
241 * Some devices (USB mass-storage in particular) may transfer
242 * garbage data together with a residue indicating that the data
243 * is invalid. Prevent the garbage from being misinterpreted
244 * and prevent security leaks by zeroing out the excess data.
245 */
246 if (unlikely(scmd->resid_len > 0 && scmd->resid_len <= bufflen))
247 memset(buffer + bufflen - scmd->resid_len, 0, scmd->resid_len);
248
249 if (args->resid)
250 *args->resid = scmd->resid_len;
251 if (args->sense)
252 memcpy(args->sense, scmd->sense_buffer, SCSI_SENSE_BUFFERSIZE);
253 if (args->sshdr)
254 scsi_normalize_sense(scmd->sense_buffer, scmd->sense_len,
255 args->sshdr);
256
257 ret = scmd->result;
258 out:
259 blk_mq_free_request(req);
260
261 return ret;
262}
263EXPORT_SYMBOL(scsi_execute_cmd);
264
265/*
266 * Wake up the error handler if necessary. Avoid as follows that the error
267 * handler is not woken up if host in-flight requests number ==
268 * shost->host_failed: use call_rcu() in scsi_eh_scmd_add() in combination
269 * with an RCU read lock in this function to ensure that this function in
270 * its entirety either finishes before scsi_eh_scmd_add() increases the
271 * host_failed counter or that it notices the shost state change made by
272 * scsi_eh_scmd_add().
273 */
274static void scsi_dec_host_busy(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
275{
276 unsigned long flags;
277
278 rcu_read_lock();
279 __clear_bit(SCMD_STATE_INFLIGHT, &cmd->state);
280 if (unlikely(scsi_host_in_recovery(shost))) {
281 unsigned int busy = scsi_host_busy(shost);
282
283 spin_lock_irqsave(shost->host_lock, flags);
284 if (shost->host_failed || shost->host_eh_scheduled)
285 scsi_eh_wakeup(shost, busy);
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
305/*
306 * Kick the queue of SCSI device @sdev if @sdev != current_sdev. Called with
307 * interrupts disabled.
308 */
309static void scsi_kick_sdev_queue(struct scsi_device *sdev, void *data)
310{
311 struct scsi_device *current_sdev = data;
312
313 if (sdev != current_sdev)
314 blk_mq_run_hw_queues(sdev->request_queue, true);
315}
316
317/*
318 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
319 * and call blk_run_queue for all the scsi_devices on the target -
320 * including current_sdev first.
321 *
322 * Called with *no* scsi locks held.
323 */
324static void scsi_single_lun_run(struct scsi_device *current_sdev)
325{
326 struct Scsi_Host *shost = current_sdev->host;
327 struct scsi_target *starget = scsi_target(current_sdev);
328 unsigned long flags;
329
330 spin_lock_irqsave(shost->host_lock, flags);
331 starget->starget_sdev_user = NULL;
332 spin_unlock_irqrestore(shost->host_lock, flags);
333
334 /*
335 * Call blk_run_queue for all LUNs on the target, starting with
336 * current_sdev. We race with others (to set starget_sdev_user),
337 * but in most cases, we will be first. Ideally, each LU on the
338 * target would get some limited time or requests on the target.
339 */
340 blk_mq_run_hw_queues(current_sdev->request_queue,
341 shost->queuecommand_may_block);
342
343 spin_lock_irqsave(shost->host_lock, flags);
344 if (!starget->starget_sdev_user)
345 __starget_for_each_device(starget, current_sdev,
346 scsi_kick_sdev_queue);
347 spin_unlock_irqrestore(shost->host_lock, flags);
348}
349
350static inline bool scsi_device_is_busy(struct scsi_device *sdev)
351{
352 if (scsi_device_busy(sdev) >= sdev->queue_depth)
353 return true;
354 if (atomic_read(&sdev->device_blocked) > 0)
355 return true;
356 return false;
357}
358
359static inline bool scsi_target_is_busy(struct scsi_target *starget)
360{
361 if (starget->can_queue > 0) {
362 if (atomic_read(&starget->target_busy) >= starget->can_queue)
363 return true;
364 if (atomic_read(&starget->target_blocked) > 0)
365 return true;
366 }
367 return false;
368}
369
370static inline bool scsi_host_is_busy(struct Scsi_Host *shost)
371{
372 if (atomic_read(&shost->host_blocked) > 0)
373 return true;
374 if (shost->host_self_blocked)
375 return true;
376 return false;
377}
378
379static void scsi_starved_list_run(struct Scsi_Host *shost)
380{
381 LIST_HEAD(starved_list);
382 struct scsi_device *sdev;
383 unsigned long flags;
384
385 spin_lock_irqsave(shost->host_lock, flags);
386 list_splice_init(&shost->starved_list, &starved_list);
387
388 while (!list_empty(&starved_list)) {
389 struct request_queue *slq;
390
391 /*
392 * As long as shost is accepting commands and we have
393 * starved queues, call blk_run_queue. scsi_request_fn
394 * drops the queue_lock and can add us back to the
395 * starved_list.
396 *
397 * host_lock protects the starved_list and starved_entry.
398 * scsi_request_fn must get the host_lock before checking
399 * or modifying starved_list or starved_entry.
400 */
401 if (scsi_host_is_busy(shost))
402 break;
403
404 sdev = list_entry(starved_list.next,
405 struct scsi_device, starved_entry);
406 list_del_init(&sdev->starved_entry);
407 if (scsi_target_is_busy(scsi_target(sdev))) {
408 list_move_tail(&sdev->starved_entry,
409 &shost->starved_list);
410 continue;
411 }
412
413 /*
414 * Once we drop the host lock, a racing scsi_remove_device()
415 * call may remove the sdev from the starved list and destroy
416 * it and the queue. Mitigate by taking a reference to the
417 * queue and never touching the sdev again after we drop the
418 * host lock. Note: if __scsi_remove_device() invokes
419 * blk_mq_destroy_queue() before the queue is run from this
420 * function then blk_run_queue() will return immediately since
421 * blk_mq_destroy_queue() marks the queue with QUEUE_FLAG_DYING.
422 */
423 slq = sdev->request_queue;
424 if (!blk_get_queue(slq))
425 continue;
426 spin_unlock_irqrestore(shost->host_lock, flags);
427
428 blk_mq_run_hw_queues(slq, false);
429 blk_put_queue(slq);
430
431 spin_lock_irqsave(shost->host_lock, flags);
432 }
433 /* put any unprocessed entries back */
434 list_splice(&starved_list, &shost->starved_list);
435 spin_unlock_irqrestore(shost->host_lock, flags);
436}
437
438/**
439 * scsi_run_queue - Select a proper request queue to serve next.
440 * @q: last request's queue
441 *
442 * The previous command was completely finished, start a new one if possible.
443 */
444static void scsi_run_queue(struct request_queue *q)
445{
446 struct scsi_device *sdev = q->queuedata;
447
448 if (scsi_target(sdev)->single_lun)
449 scsi_single_lun_run(sdev);
450 if (!list_empty(&sdev->host->starved_list))
451 scsi_starved_list_run(sdev->host);
452
453 /* Note: blk_mq_kick_requeue_list() runs the queue asynchronously. */
454 blk_mq_kick_requeue_list(q);
455}
456
457void scsi_requeue_run_queue(struct work_struct *work)
458{
459 struct scsi_device *sdev;
460 struct request_queue *q;
461
462 sdev = container_of(work, struct scsi_device, requeue_work);
463 q = sdev->request_queue;
464 scsi_run_queue(q);
465}
466
467void scsi_run_host_queues(struct Scsi_Host *shost)
468{
469 struct scsi_device *sdev;
470
471 shost_for_each_device(sdev, shost)
472 scsi_run_queue(sdev->request_queue);
473}
474
475static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
476{
477 if (!blk_rq_is_passthrough(scsi_cmd_to_rq(cmd))) {
478 struct scsi_driver *drv = scsi_cmd_to_driver(cmd);
479
480 if (drv->uninit_command)
481 drv->uninit_command(cmd);
482 }
483}
484
485void scsi_free_sgtables(struct scsi_cmnd *cmd)
486{
487 if (cmd->sdb.table.nents)
488 sg_free_table_chained(&cmd->sdb.table,
489 SCSI_INLINE_SG_CNT);
490 if (scsi_prot_sg_count(cmd))
491 sg_free_table_chained(&cmd->prot_sdb->table,
492 SCSI_INLINE_PROT_SG_CNT);
493}
494EXPORT_SYMBOL_GPL(scsi_free_sgtables);
495
496static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
497{
498 scsi_free_sgtables(cmd);
499 scsi_uninit_cmd(cmd);
500}
501
502static void scsi_run_queue_async(struct scsi_device *sdev)
503{
504 if (scsi_host_in_recovery(sdev->host))
505 return;
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
582/**
583 * scsi_result_to_blk_status - translate a SCSI result code into blk_status_t
584 * @result: scsi error code
585 *
586 * Translate a SCSI result code into a blk_status_t value.
587 */
588static blk_status_t scsi_result_to_blk_status(int result)
589{
590 /*
591 * Check the scsi-ml byte first in case we converted a host or status
592 * byte.
593 */
594 switch (scsi_ml_byte(result)) {
595 case SCSIML_STAT_OK:
596 break;
597 case SCSIML_STAT_RESV_CONFLICT:
598 return BLK_STS_RESV_CONFLICT;
599 case SCSIML_STAT_NOSPC:
600 return BLK_STS_NOSPC;
601 case SCSIML_STAT_MED_ERROR:
602 return BLK_STS_MEDIUM;
603 case SCSIML_STAT_TGT_FAILURE:
604 return BLK_STS_TARGET;
605 case SCSIML_STAT_DL_TIMEOUT:
606 return BLK_STS_DURATION_LIMIT;
607 }
608
609 switch (host_byte(result)) {
610 case DID_OK:
611 if (scsi_status_is_good(result))
612 return BLK_STS_OK;
613 return BLK_STS_IOERR;
614 case DID_TRANSPORT_FAILFAST:
615 case DID_TRANSPORT_MARGINAL:
616 return BLK_STS_TRANSPORT;
617 default:
618 return BLK_STS_IOERR;
619 }
620}
621
622/**
623 * scsi_rq_err_bytes - determine number of bytes till the next failure boundary
624 * @rq: request to examine
625 *
626 * Description:
627 * A request could be merge of IOs which require different failure
628 * handling. This function determines the number of bytes which
629 * can be failed from the beginning of the request without
630 * crossing into area which need to be retried further.
631 *
632 * Return:
633 * The number of bytes to fail.
634 */
635static unsigned int scsi_rq_err_bytes(const struct request *rq)
636{
637 blk_opf_t ff = rq->cmd_flags & REQ_FAILFAST_MASK;
638 unsigned int bytes = 0;
639 struct bio *bio;
640
641 if (!(rq->rq_flags & RQF_MIXED_MERGE))
642 return blk_rq_bytes(rq);
643
644 /*
645 * Currently the only 'mixing' which can happen is between
646 * different fastfail types. We can safely fail portions
647 * which have all the failfast bits that the first one has -
648 * the ones which are at least as eager to fail as the first
649 * one.
650 */
651 for (bio = rq->bio; bio; bio = bio->bi_next) {
652 if ((bio->bi_opf & ff) != ff)
653 break;
654 bytes += bio->bi_iter.bi_size;
655 }
656
657 /* this could lead to infinite loop */
658 BUG_ON(blk_rq_bytes(rq) && !bytes);
659 return bytes;
660}
661
662static bool scsi_cmd_runtime_exceeced(struct scsi_cmnd *cmd)
663{
664 struct request *req = scsi_cmd_to_rq(cmd);
665 unsigned long wait_for;
666
667 if (cmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT)
668 return false;
669
670 wait_for = (cmd->allowed + 1) * req->timeout;
671 if (time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
672 scmd_printk(KERN_ERR, cmd, "timing out command, waited %lus\n",
673 wait_for/HZ);
674 return true;
675 }
676 return false;
677}
678
679/*
680 * When ALUA transition state is returned, reprep the cmd to
681 * use the ALUA handler's transition timeout. Delay the reprep
682 * 1 sec to avoid aggressive retries of the target in that
683 * state.
684 */
685#define ALUA_TRANSITION_REPREP_DELAY 1000
686
687/* Helper for scsi_io_completion() when special action required. */
688static void scsi_io_completion_action(struct scsi_cmnd *cmd, int result)
689{
690 struct request *req = scsi_cmd_to_rq(cmd);
691 int level = 0;
692 enum {ACTION_FAIL, ACTION_REPREP, ACTION_DELAYED_REPREP,
693 ACTION_RETRY, ACTION_DELAYED_RETRY} action;
694 struct scsi_sense_hdr sshdr;
695 bool sense_valid;
696 bool sense_current = true; /* false implies "deferred sense" */
697 blk_status_t blk_stat;
698
699 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
700 if (sense_valid)
701 sense_current = !scsi_sense_is_deferred(&sshdr);
702
703 blk_stat = scsi_result_to_blk_status(result);
704
705 if (host_byte(result) == DID_RESET) {
706 /* Third party bus reset or reset for error recovery
707 * reasons. Just retry the command and see what
708 * happens.
709 */
710 action = ACTION_RETRY;
711 } else if (sense_valid && sense_current) {
712 switch (sshdr.sense_key) {
713 case UNIT_ATTENTION:
714 if (cmd->device->removable) {
715 /* Detected disc change. Set a bit
716 * and quietly refuse further access.
717 */
718 cmd->device->changed = 1;
719 action = ACTION_FAIL;
720 } else {
721 /* Must have been a power glitch, or a
722 * bus reset. Could not have been a
723 * media change, so we just retry the
724 * command and see what happens.
725 */
726 action = ACTION_RETRY;
727 }
728 break;
729 case ILLEGAL_REQUEST:
730 /* If we had an ILLEGAL REQUEST returned, then
731 * we may have performed an unsupported
732 * command. The only thing this should be
733 * would be a ten byte read where only a six
734 * byte read was supported. Also, on a system
735 * where READ CAPACITY failed, we may have
736 * read past the end of the disk.
737 */
738 if ((cmd->device->use_10_for_rw &&
739 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
740 (cmd->cmnd[0] == READ_10 ||
741 cmd->cmnd[0] == WRITE_10)) {
742 /* This will issue a new 6-byte command. */
743 cmd->device->use_10_for_rw = 0;
744 action = ACTION_REPREP;
745 } else if (sshdr.asc == 0x10) /* DIX */ {
746 action = ACTION_FAIL;
747 blk_stat = BLK_STS_PROTECTION;
748 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
749 } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
750 action = ACTION_FAIL;
751 blk_stat = BLK_STS_TARGET;
752 } else
753 action = ACTION_FAIL;
754 break;
755 case ABORTED_COMMAND:
756 action = ACTION_FAIL;
757 if (sshdr.asc == 0x10) /* DIF */
758 blk_stat = BLK_STS_PROTECTION;
759 break;
760 case NOT_READY:
761 /* If the device is in the process of becoming
762 * ready, or has a temporary blockage, retry.
763 */
764 if (sshdr.asc == 0x04) {
765 switch (sshdr.ascq) {
766 case 0x01: /* becoming ready */
767 case 0x04: /* format in progress */
768 case 0x05: /* rebuild in progress */
769 case 0x06: /* recalculation in progress */
770 case 0x07: /* operation in progress */
771 case 0x08: /* Long write in progress */
772 case 0x09: /* self test in progress */
773 case 0x11: /* notify (enable spinup) required */
774 case 0x14: /* space allocation in progress */
775 case 0x1a: /* start stop unit in progress */
776 case 0x1b: /* sanitize in progress */
777 case 0x1d: /* configuration in progress */
778 case 0x24: /* depopulation in progress */
779 case 0x25: /* depopulation restore in progress */
780 action = ACTION_DELAYED_RETRY;
781 break;
782 case 0x0a: /* ALUA state transition */
783 action = ACTION_DELAYED_REPREP;
784 break;
785 default:
786 action = ACTION_FAIL;
787 break;
788 }
789 } else
790 action = ACTION_FAIL;
791 break;
792 case VOLUME_OVERFLOW:
793 /* See SSC3rXX or current. */
794 action = ACTION_FAIL;
795 break;
796 case DATA_PROTECT:
797 action = ACTION_FAIL;
798 if ((sshdr.asc == 0x0C && sshdr.ascq == 0x12) ||
799 (sshdr.asc == 0x55 &&
800 (sshdr.ascq == 0x0E || sshdr.ascq == 0x0F))) {
801 /* Insufficient zone resources */
802 blk_stat = BLK_STS_ZONE_OPEN_RESOURCE;
803 }
804 break;
805 case COMPLETED:
806 fallthrough;
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 (token < 0)
1257 return -1;
1258
1259 if (!atomic_read(&sdev->device_blocked))
1260 return token;
1261
1262 /*
1263 * Only unblock if no other commands are pending and
1264 * if device_blocked has decreased to zero
1265 */
1266 if (scsi_device_busy(sdev) > 1 ||
1267 atomic_dec_return(&sdev->device_blocked) > 0) {
1268 sbitmap_put(&sdev->budget_map, token);
1269 return -1;
1270 }
1271
1272 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev,
1273 "unblocking device at zero depth\n"));
1274
1275 return token;
1276}
1277
1278/*
1279 * scsi_target_queue_ready: checks if there we can send commands to target
1280 * @sdev: scsi device on starget to check.
1281 */
1282static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1283 struct scsi_device *sdev)
1284{
1285 struct scsi_target *starget = scsi_target(sdev);
1286 unsigned int busy;
1287
1288 if (starget->single_lun) {
1289 spin_lock_irq(shost->host_lock);
1290 if (starget->starget_sdev_user &&
1291 starget->starget_sdev_user != sdev) {
1292 spin_unlock_irq(shost->host_lock);
1293 return 0;
1294 }
1295 starget->starget_sdev_user = sdev;
1296 spin_unlock_irq(shost->host_lock);
1297 }
1298
1299 if (starget->can_queue <= 0)
1300 return 1;
1301
1302 busy = atomic_inc_return(&starget->target_busy) - 1;
1303 if (atomic_read(&starget->target_blocked) > 0) {
1304 if (busy)
1305 goto starved;
1306
1307 /*
1308 * unblock after target_blocked iterates to zero
1309 */
1310 if (atomic_dec_return(&starget->target_blocked) > 0)
1311 goto out_dec;
1312
1313 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1314 "unblocking target at zero depth\n"));
1315 }
1316
1317 if (busy >= starget->can_queue)
1318 goto starved;
1319
1320 return 1;
1321
1322starved:
1323 spin_lock_irq(shost->host_lock);
1324 list_move_tail(&sdev->starved_entry, &shost->starved_list);
1325 spin_unlock_irq(shost->host_lock);
1326out_dec:
1327 if (starget->can_queue > 0)
1328 atomic_dec(&starget->target_busy);
1329 return 0;
1330}
1331
1332/*
1333 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1334 * return 0. We must end up running the queue again whenever 0 is
1335 * returned, else IO can hang.
1336 */
1337static inline int scsi_host_queue_ready(struct request_queue *q,
1338 struct Scsi_Host *shost,
1339 struct scsi_device *sdev,
1340 struct scsi_cmnd *cmd)
1341{
1342 if (atomic_read(&shost->host_blocked) > 0) {
1343 if (scsi_host_busy(shost) > 0)
1344 goto starved;
1345
1346 /*
1347 * unblock after host_blocked iterates to zero
1348 */
1349 if (atomic_dec_return(&shost->host_blocked) > 0)
1350 goto out_dec;
1351
1352 SCSI_LOG_MLQUEUE(3,
1353 shost_printk(KERN_INFO, shost,
1354 "unblocking host at zero depth\n"));
1355 }
1356
1357 if (shost->host_self_blocked)
1358 goto starved;
1359
1360 /* We're OK to process the command, so we can't be starved */
1361 if (!list_empty(&sdev->starved_entry)) {
1362 spin_lock_irq(shost->host_lock);
1363 if (!list_empty(&sdev->starved_entry))
1364 list_del_init(&sdev->starved_entry);
1365 spin_unlock_irq(shost->host_lock);
1366 }
1367
1368 __set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1369
1370 return 1;
1371
1372starved:
1373 spin_lock_irq(shost->host_lock);
1374 if (list_empty(&sdev->starved_entry))
1375 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1376 spin_unlock_irq(shost->host_lock);
1377out_dec:
1378 scsi_dec_host_busy(shost, cmd);
1379 return 0;
1380}
1381
1382/*
1383 * Busy state exporting function for request stacking drivers.
1384 *
1385 * For efficiency, no lock is taken to check the busy state of
1386 * shost/starget/sdev, since the returned value is not guaranteed and
1387 * may be changed after request stacking drivers call the function,
1388 * regardless of taking lock or not.
1389 *
1390 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1391 * needs to return 'not busy'. Otherwise, request stacking drivers
1392 * may hold requests forever.
1393 */
1394static bool scsi_mq_lld_busy(struct request_queue *q)
1395{
1396 struct scsi_device *sdev = q->queuedata;
1397 struct Scsi_Host *shost;
1398
1399 if (blk_queue_dying(q))
1400 return false;
1401
1402 shost = sdev->host;
1403
1404 /*
1405 * Ignore host/starget busy state.
1406 * Since block layer does not have a concept of fairness across
1407 * multiple queues, congestion of host/starget needs to be handled
1408 * in SCSI layer.
1409 */
1410 if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
1411 return true;
1412
1413 return false;
1414}
1415
1416/*
1417 * Block layer request completion callback. May be called from interrupt
1418 * context.
1419 */
1420static void scsi_complete(struct request *rq)
1421{
1422 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1423 enum scsi_disposition disposition;
1424
1425 INIT_LIST_HEAD(&cmd->eh_entry);
1426
1427 atomic_inc(&cmd->device->iodone_cnt);
1428 if (cmd->result)
1429 atomic_inc(&cmd->device->ioerr_cnt);
1430
1431 disposition = scsi_decide_disposition(cmd);
1432 if (disposition != SUCCESS && scsi_cmd_runtime_exceeced(cmd))
1433 disposition = SUCCESS;
1434
1435 scsi_log_completion(cmd, disposition);
1436
1437 switch (disposition) {
1438 case SUCCESS:
1439 scsi_finish_command(cmd);
1440 break;
1441 case NEEDS_RETRY:
1442 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
1443 break;
1444 case ADD_TO_MLQUEUE:
1445 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1446 break;
1447 default:
1448 scsi_eh_scmd_add(cmd);
1449 break;
1450 }
1451}
1452
1453/**
1454 * scsi_dispatch_cmd - Dispatch a command to the low-level driver.
1455 * @cmd: command block we are dispatching.
1456 *
1457 * Return: nonzero return request was rejected and device's queue needs to be
1458 * plugged.
1459 */
1460static int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
1461{
1462 struct Scsi_Host *host = cmd->device->host;
1463 int rtn = 0;
1464
1465 atomic_inc(&cmd->device->iorequest_cnt);
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 atomic_dec(&cmd->device->iorequest_cnt);
1488 return SCSI_MLQUEUE_DEVICE_BUSY;
1489 }
1490
1491 /* Store the LUN value in cmnd, if needed. */
1492 if (cmd->device->lun_in_cdb)
1493 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
1494 (cmd->device->lun << 5 & 0xe0);
1495
1496 scsi_log_send(cmd);
1497
1498 /*
1499 * Before we queue this command, check if the command
1500 * length exceeds what the host adapter can handle.
1501 */
1502 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
1503 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1504 "queuecommand : command too long. "
1505 "cdb_size=%d host->max_cmd_len=%d\n",
1506 cmd->cmd_len, cmd->device->host->max_cmd_len));
1507 cmd->result = (DID_ABORT << 16);
1508 goto done;
1509 }
1510
1511 if (unlikely(host->shost_state == SHOST_DEL)) {
1512 cmd->result = (DID_NO_CONNECT << 16);
1513 goto done;
1514
1515 }
1516
1517 trace_scsi_dispatch_cmd_start(cmd);
1518 rtn = host->hostt->queuecommand(host, cmd);
1519 if (rtn) {
1520 atomic_dec(&cmd->device->iorequest_cnt);
1521 trace_scsi_dispatch_cmd_error(cmd, rtn);
1522 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
1523 rtn != SCSI_MLQUEUE_TARGET_BUSY)
1524 rtn = SCSI_MLQUEUE_HOST_BUSY;
1525
1526 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1527 "queuecommand : request rejected\n"));
1528 }
1529
1530 return rtn;
1531 done:
1532 scsi_done(cmd);
1533 return 0;
1534}
1535
1536/* Size in bytes of the sg-list stored in the scsi-mq command-private data. */
1537static unsigned int scsi_mq_inline_sgl_size(struct Scsi_Host *shost)
1538{
1539 return min_t(unsigned int, shost->sg_tablesize, SCSI_INLINE_SG_CNT) *
1540 sizeof(struct scatterlist);
1541}
1542
1543static blk_status_t scsi_prepare_cmd(struct request *req)
1544{
1545 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1546 struct scsi_device *sdev = req->q->queuedata;
1547 struct Scsi_Host *shost = sdev->host;
1548 bool in_flight = test_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1549 struct scatterlist *sg;
1550
1551 scsi_init_command(sdev, cmd);
1552
1553 cmd->eh_eflags = 0;
1554 cmd->prot_type = 0;
1555 cmd->prot_flags = 0;
1556 cmd->submitter = 0;
1557 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1558 cmd->underflow = 0;
1559 cmd->transfersize = 0;
1560 cmd->host_scribble = NULL;
1561 cmd->result = 0;
1562 cmd->extra_len = 0;
1563 cmd->state = 0;
1564 if (in_flight)
1565 __set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1566
1567 /*
1568 * Only clear the driver-private command data if the LLD does not supply
1569 * a function to initialize that data.
1570 */
1571 if (!shost->hostt->init_cmd_priv)
1572 memset(cmd + 1, 0, shost->hostt->cmd_size);
1573
1574 cmd->prot_op = SCSI_PROT_NORMAL;
1575 if (blk_rq_bytes(req))
1576 cmd->sc_data_direction = rq_dma_dir(req);
1577 else
1578 cmd->sc_data_direction = DMA_NONE;
1579
1580 sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
1581 cmd->sdb.table.sgl = sg;
1582
1583 if (scsi_host_get_prot(shost)) {
1584 memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer));
1585
1586 cmd->prot_sdb->table.sgl =
1587 (struct scatterlist *)(cmd->prot_sdb + 1);
1588 }
1589
1590 /*
1591 * Special handling for passthrough commands, which don't go to the ULP
1592 * at all:
1593 */
1594 if (blk_rq_is_passthrough(req))
1595 return scsi_setup_scsi_cmnd(sdev, req);
1596
1597 if (sdev->handler && sdev->handler->prep_fn) {
1598 blk_status_t ret = sdev->handler->prep_fn(sdev, req);
1599
1600 if (ret != BLK_STS_OK)
1601 return ret;
1602 }
1603
1604 /* Usually overridden by the ULP */
1605 cmd->allowed = 0;
1606 memset(cmd->cmnd, 0, sizeof(cmd->cmnd));
1607 return scsi_cmd_to_driver(cmd)->init_command(cmd);
1608}
1609
1610static void scsi_done_internal(struct scsi_cmnd *cmd, bool complete_directly)
1611{
1612 struct request *req = scsi_cmd_to_rq(cmd);
1613
1614 switch (cmd->submitter) {
1615 case SUBMITTED_BY_BLOCK_LAYER:
1616 break;
1617 case SUBMITTED_BY_SCSI_ERROR_HANDLER:
1618 return scsi_eh_done(cmd);
1619 case SUBMITTED_BY_SCSI_RESET_IOCTL:
1620 return;
1621 }
1622
1623 if (unlikely(blk_should_fake_timeout(scsi_cmd_to_rq(cmd)->q)))
1624 return;
1625 if (unlikely(test_and_set_bit(SCMD_STATE_COMPLETE, &cmd->state)))
1626 return;
1627 trace_scsi_dispatch_cmd_done(cmd);
1628
1629 if (complete_directly)
1630 blk_mq_complete_request_direct(req, scsi_complete);
1631 else
1632 blk_mq_complete_request(req);
1633}
1634
1635void scsi_done(struct scsi_cmnd *cmd)
1636{
1637 scsi_done_internal(cmd, false);
1638}
1639EXPORT_SYMBOL(scsi_done);
1640
1641void scsi_done_direct(struct scsi_cmnd *cmd)
1642{
1643 scsi_done_internal(cmd, true);
1644}
1645EXPORT_SYMBOL(scsi_done_direct);
1646
1647static void scsi_mq_put_budget(struct request_queue *q, int budget_token)
1648{
1649 struct scsi_device *sdev = q->queuedata;
1650
1651 sbitmap_put(&sdev->budget_map, budget_token);
1652}
1653
1654/*
1655 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
1656 * not change behaviour from the previous unplug mechanism, experimentation
1657 * may prove this needs changing.
1658 */
1659#define SCSI_QUEUE_DELAY 3
1660
1661static int scsi_mq_get_budget(struct request_queue *q)
1662{
1663 struct scsi_device *sdev = q->queuedata;
1664 int token = scsi_dev_queue_ready(q, sdev);
1665
1666 if (token >= 0)
1667 return token;
1668
1669 atomic_inc(&sdev->restarts);
1670
1671 /*
1672 * Orders atomic_inc(&sdev->restarts) and atomic_read(&sdev->device_busy).
1673 * .restarts must be incremented before .device_busy is read because the
1674 * code in scsi_run_queue_async() depends on the order of these operations.
1675 */
1676 smp_mb__after_atomic();
1677
1678 /*
1679 * If all in-flight requests originated from this LUN are completed
1680 * before reading .device_busy, sdev->device_busy will be observed as
1681 * zero, then blk_mq_delay_run_hw_queues() will dispatch this request
1682 * soon. Otherwise, completion of one of these requests will observe
1683 * the .restarts flag, and the request queue will be run for handling
1684 * this request, see scsi_end_request().
1685 */
1686 if (unlikely(scsi_device_busy(sdev) == 0 &&
1687 !scsi_device_blocked(sdev)))
1688 blk_mq_delay_run_hw_queues(sdev->request_queue, SCSI_QUEUE_DELAY);
1689 return -1;
1690}
1691
1692static void scsi_mq_set_rq_budget_token(struct request *req, int token)
1693{
1694 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1695
1696 cmd->budget_token = token;
1697}
1698
1699static int scsi_mq_get_rq_budget_token(struct request *req)
1700{
1701 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1702
1703 return cmd->budget_token;
1704}
1705
1706static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
1707 const struct blk_mq_queue_data *bd)
1708{
1709 struct request *req = bd->rq;
1710 struct request_queue *q = req->q;
1711 struct scsi_device *sdev = q->queuedata;
1712 struct Scsi_Host *shost = sdev->host;
1713 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1714 blk_status_t ret;
1715 int reason;
1716
1717 WARN_ON_ONCE(cmd->budget_token < 0);
1718
1719 /*
1720 * If the device is not in running state we will reject some or all
1721 * commands.
1722 */
1723 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
1724 ret = scsi_device_state_check(sdev, req);
1725 if (ret != BLK_STS_OK)
1726 goto out_put_budget;
1727 }
1728
1729 ret = BLK_STS_RESOURCE;
1730 if (!scsi_target_queue_ready(shost, sdev))
1731 goto out_put_budget;
1732 if (unlikely(scsi_host_in_recovery(shost))) {
1733 if (cmd->flags & SCMD_FAIL_IF_RECOVERING)
1734 ret = BLK_STS_OFFLINE;
1735 goto out_dec_target_busy;
1736 }
1737 if (!scsi_host_queue_ready(q, shost, sdev, cmd))
1738 goto out_dec_target_busy;
1739
1740 if (!(req->rq_flags & RQF_DONTPREP)) {
1741 ret = scsi_prepare_cmd(req);
1742 if (ret != BLK_STS_OK)
1743 goto out_dec_host_busy;
1744 req->rq_flags |= RQF_DONTPREP;
1745 } else {
1746 clear_bit(SCMD_STATE_COMPLETE, &cmd->state);
1747 }
1748
1749 cmd->flags &= SCMD_PRESERVED_FLAGS;
1750 if (sdev->simple_tags)
1751 cmd->flags |= SCMD_TAGGED;
1752 if (bd->last)
1753 cmd->flags |= SCMD_LAST;
1754
1755 scsi_set_resid(cmd, 0);
1756 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
1757 cmd->submitter = SUBMITTED_BY_BLOCK_LAYER;
1758
1759 blk_mq_start_request(req);
1760 reason = scsi_dispatch_cmd(cmd);
1761 if (reason) {
1762 scsi_set_blocked(cmd, reason);
1763 ret = BLK_STS_RESOURCE;
1764 goto out_dec_host_busy;
1765 }
1766
1767 return BLK_STS_OK;
1768
1769out_dec_host_busy:
1770 scsi_dec_host_busy(shost, cmd);
1771out_dec_target_busy:
1772 if (scsi_target(sdev)->can_queue > 0)
1773 atomic_dec(&scsi_target(sdev)->target_busy);
1774out_put_budget:
1775 scsi_mq_put_budget(q, cmd->budget_token);
1776 cmd->budget_token = -1;
1777 switch (ret) {
1778 case BLK_STS_OK:
1779 break;
1780 case BLK_STS_RESOURCE:
1781 case BLK_STS_ZONE_RESOURCE:
1782 if (scsi_device_blocked(sdev))
1783 ret = BLK_STS_DEV_RESOURCE;
1784 break;
1785 case BLK_STS_AGAIN:
1786 cmd->result = DID_BUS_BUSY << 16;
1787 if (req->rq_flags & RQF_DONTPREP)
1788 scsi_mq_uninit_cmd(cmd);
1789 break;
1790 default:
1791 if (unlikely(!scsi_device_online(sdev)))
1792 cmd->result = DID_NO_CONNECT << 16;
1793 else
1794 cmd->result = DID_ERROR << 16;
1795 /*
1796 * Make sure to release all allocated resources when
1797 * we hit an error, as we will never see this command
1798 * again.
1799 */
1800 if (req->rq_flags & RQF_DONTPREP)
1801 scsi_mq_uninit_cmd(cmd);
1802 scsi_run_queue_async(sdev);
1803 break;
1804 }
1805 return ret;
1806}
1807
1808static int scsi_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
1809 unsigned int hctx_idx, unsigned int numa_node)
1810{
1811 struct Scsi_Host *shost = set->driver_data;
1812 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1813 struct scatterlist *sg;
1814 int ret = 0;
1815
1816 cmd->sense_buffer =
1817 kmem_cache_alloc_node(scsi_sense_cache, GFP_KERNEL, numa_node);
1818 if (!cmd->sense_buffer)
1819 return -ENOMEM;
1820
1821 if (scsi_host_get_prot(shost)) {
1822 sg = (void *)cmd + sizeof(struct scsi_cmnd) +
1823 shost->hostt->cmd_size;
1824 cmd->prot_sdb = (void *)sg + scsi_mq_inline_sgl_size(shost);
1825 }
1826
1827 if (shost->hostt->init_cmd_priv) {
1828 ret = shost->hostt->init_cmd_priv(shost, cmd);
1829 if (ret < 0)
1830 kmem_cache_free(scsi_sense_cache, cmd->sense_buffer);
1831 }
1832
1833 return ret;
1834}
1835
1836static void scsi_mq_exit_request(struct blk_mq_tag_set *set, struct request *rq,
1837 unsigned int hctx_idx)
1838{
1839 struct Scsi_Host *shost = set->driver_data;
1840 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1841
1842 if (shost->hostt->exit_cmd_priv)
1843 shost->hostt->exit_cmd_priv(shost, cmd);
1844 kmem_cache_free(scsi_sense_cache, cmd->sense_buffer);
1845}
1846
1847
1848static int scsi_mq_poll(struct blk_mq_hw_ctx *hctx, struct io_comp_batch *iob)
1849{
1850 struct Scsi_Host *shost = hctx->driver_data;
1851
1852 if (shost->hostt->mq_poll)
1853 return shost->hostt->mq_poll(shost, hctx->queue_num);
1854
1855 return 0;
1856}
1857
1858static int scsi_init_hctx(struct blk_mq_hw_ctx *hctx, void *data,
1859 unsigned int hctx_idx)
1860{
1861 struct Scsi_Host *shost = data;
1862
1863 hctx->driver_data = shost;
1864 return 0;
1865}
1866
1867static void scsi_map_queues(struct blk_mq_tag_set *set)
1868{
1869 struct Scsi_Host *shost = container_of(set, struct Scsi_Host, tag_set);
1870
1871 if (shost->hostt->map_queues)
1872 return shost->hostt->map_queues(shost);
1873 blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]);
1874}
1875
1876void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
1877{
1878 struct device *dev = shost->dma_dev;
1879
1880 /*
1881 * this limit is imposed by hardware restrictions
1882 */
1883 blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
1884 SG_MAX_SEGMENTS));
1885
1886 if (scsi_host_prot_dma(shost)) {
1887 shost->sg_prot_tablesize =
1888 min_not_zero(shost->sg_prot_tablesize,
1889 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
1890 BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
1891 blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
1892 }
1893
1894 blk_queue_max_hw_sectors(q, shost->max_sectors);
1895 blk_queue_segment_boundary(q, shost->dma_boundary);
1896 dma_set_seg_boundary(dev, shost->dma_boundary);
1897
1898 blk_queue_max_segment_size(q, shost->max_segment_size);
1899 blk_queue_virt_boundary(q, shost->virt_boundary_mask);
1900 dma_set_max_seg_size(dev, queue_max_segment_size(q));
1901
1902 /*
1903 * Set a reasonable default alignment: The larger of 32-byte (dword),
1904 * which is a common minimum for HBAs, and the minimum DMA alignment,
1905 * which is set by the platform.
1906 *
1907 * Devices that require a bigger alignment can increase it later.
1908 */
1909 blk_queue_dma_alignment(q, max(4, dma_get_cache_alignment()) - 1);
1910}
1911EXPORT_SYMBOL_GPL(__scsi_init_queue);
1912
1913static const struct blk_mq_ops scsi_mq_ops_no_commit = {
1914 .get_budget = scsi_mq_get_budget,
1915 .put_budget = scsi_mq_put_budget,
1916 .queue_rq = scsi_queue_rq,
1917 .complete = scsi_complete,
1918 .timeout = scsi_timeout,
1919#ifdef CONFIG_BLK_DEBUG_FS
1920 .show_rq = scsi_show_rq,
1921#endif
1922 .init_request = scsi_mq_init_request,
1923 .exit_request = scsi_mq_exit_request,
1924 .cleanup_rq = scsi_cleanup_rq,
1925 .busy = scsi_mq_lld_busy,
1926 .map_queues = scsi_map_queues,
1927 .init_hctx = scsi_init_hctx,
1928 .poll = scsi_mq_poll,
1929 .set_rq_budget_token = scsi_mq_set_rq_budget_token,
1930 .get_rq_budget_token = scsi_mq_get_rq_budget_token,
1931};
1932
1933
1934static void scsi_commit_rqs(struct blk_mq_hw_ctx *hctx)
1935{
1936 struct Scsi_Host *shost = hctx->driver_data;
1937
1938 shost->hostt->commit_rqs(shost, hctx->queue_num);
1939}
1940
1941static const struct blk_mq_ops scsi_mq_ops = {
1942 .get_budget = scsi_mq_get_budget,
1943 .put_budget = scsi_mq_put_budget,
1944 .queue_rq = scsi_queue_rq,
1945 .commit_rqs = scsi_commit_rqs,
1946 .complete = scsi_complete,
1947 .timeout = scsi_timeout,
1948#ifdef CONFIG_BLK_DEBUG_FS
1949 .show_rq = scsi_show_rq,
1950#endif
1951 .init_request = scsi_mq_init_request,
1952 .exit_request = scsi_mq_exit_request,
1953 .cleanup_rq = scsi_cleanup_rq,
1954 .busy = scsi_mq_lld_busy,
1955 .map_queues = scsi_map_queues,
1956 .init_hctx = scsi_init_hctx,
1957 .poll = scsi_mq_poll,
1958 .set_rq_budget_token = scsi_mq_set_rq_budget_token,
1959 .get_rq_budget_token = scsi_mq_get_rq_budget_token,
1960};
1961
1962int scsi_mq_setup_tags(struct Scsi_Host *shost)
1963{
1964 unsigned int cmd_size, sgl_size;
1965 struct blk_mq_tag_set *tag_set = &shost->tag_set;
1966
1967 sgl_size = max_t(unsigned int, sizeof(struct scatterlist),
1968 scsi_mq_inline_sgl_size(shost));
1969 cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size;
1970 if (scsi_host_get_prot(shost))
1971 cmd_size += sizeof(struct scsi_data_buffer) +
1972 sizeof(struct scatterlist) * SCSI_INLINE_PROT_SG_CNT;
1973
1974 memset(tag_set, 0, sizeof(*tag_set));
1975 if (shost->hostt->commit_rqs)
1976 tag_set->ops = &scsi_mq_ops;
1977 else
1978 tag_set->ops = &scsi_mq_ops_no_commit;
1979 tag_set->nr_hw_queues = shost->nr_hw_queues ? : 1;
1980 tag_set->nr_maps = shost->nr_maps ? : 1;
1981 tag_set->queue_depth = shost->can_queue;
1982 tag_set->cmd_size = cmd_size;
1983 tag_set->numa_node = dev_to_node(shost->dma_dev);
1984 tag_set->flags = BLK_MQ_F_SHOULD_MERGE;
1985 tag_set->flags |=
1986 BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
1987 if (shost->queuecommand_may_block)
1988 tag_set->flags |= BLK_MQ_F_BLOCKING;
1989 tag_set->driver_data = shost;
1990 if (shost->host_tagset)
1991 tag_set->flags |= BLK_MQ_F_TAG_HCTX_SHARED;
1992
1993 return blk_mq_alloc_tag_set(tag_set);
1994}
1995
1996void scsi_mq_free_tags(struct kref *kref)
1997{
1998 struct Scsi_Host *shost = container_of(kref, typeof(*shost),
1999 tagset_refcnt);
2000
2001 blk_mq_free_tag_set(&shost->tag_set);
2002 complete(&shost->tagset_freed);
2003}
2004
2005/**
2006 * scsi_device_from_queue - return sdev associated with a request_queue
2007 * @q: The request queue to return the sdev from
2008 *
2009 * Return the sdev associated with a request queue or NULL if the
2010 * request_queue does not reference a SCSI device.
2011 */
2012struct scsi_device *scsi_device_from_queue(struct request_queue *q)
2013{
2014 struct scsi_device *sdev = NULL;
2015
2016 if (q->mq_ops == &scsi_mq_ops_no_commit ||
2017 q->mq_ops == &scsi_mq_ops)
2018 sdev = q->queuedata;
2019 if (!sdev || !get_device(&sdev->sdev_gendev))
2020 sdev = NULL;
2021
2022 return sdev;
2023}
2024/*
2025 * pktcdvd should have been integrated into the SCSI layers, but for historical
2026 * reasons like the old IDE driver it isn't. This export allows it to safely
2027 * probe if a given device is a SCSI one and only attach to that.
2028 */
2029#ifdef CONFIG_CDROM_PKTCDVD_MODULE
2030EXPORT_SYMBOL_GPL(scsi_device_from_queue);
2031#endif
2032
2033/**
2034 * scsi_block_requests - Utility function used by low-level drivers to prevent
2035 * further commands from being queued to the device.
2036 * @shost: host in question
2037 *
2038 * There is no timer nor any other means by which the requests get unblocked
2039 * other than the low-level driver calling scsi_unblock_requests().
2040 */
2041void scsi_block_requests(struct Scsi_Host *shost)
2042{
2043 shost->host_self_blocked = 1;
2044}
2045EXPORT_SYMBOL(scsi_block_requests);
2046
2047/**
2048 * scsi_unblock_requests - Utility function used by low-level drivers to allow
2049 * further commands to be queued to the device.
2050 * @shost: host in question
2051 *
2052 * There is no timer nor any other means by which the requests get unblocked
2053 * other than the low-level driver calling scsi_unblock_requests(). This is done
2054 * as an API function so that changes to the internals of the scsi mid-layer
2055 * won't require wholesale changes to drivers that use this feature.
2056 */
2057void scsi_unblock_requests(struct Scsi_Host *shost)
2058{
2059 shost->host_self_blocked = 0;
2060 scsi_run_host_queues(shost);
2061}
2062EXPORT_SYMBOL(scsi_unblock_requests);
2063
2064void scsi_exit_queue(void)
2065{
2066 kmem_cache_destroy(scsi_sense_cache);
2067}
2068
2069/**
2070 * scsi_mode_select - issue a mode select
2071 * @sdev: SCSI device to be queried
2072 * @pf: Page format bit (1 == standard, 0 == vendor specific)
2073 * @sp: Save page bit (0 == don't save, 1 == save)
2074 * @buffer: request buffer (may not be smaller than eight bytes)
2075 * @len: length of request buffer.
2076 * @timeout: command timeout
2077 * @retries: number of retries before failing
2078 * @data: returns a structure abstracting the mode header data
2079 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2080 * must be SCSI_SENSE_BUFFERSIZE big.
2081 *
2082 * Returns zero if successful; negative error number or scsi
2083 * status on error
2084 *
2085 */
2086int scsi_mode_select(struct scsi_device *sdev, int pf, int sp,
2087 unsigned char *buffer, int len, int timeout, int retries,
2088 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2089{
2090 unsigned char cmd[10];
2091 unsigned char *real_buffer;
2092 const struct scsi_exec_args exec_args = {
2093 .sshdr = sshdr,
2094 };
2095 int ret;
2096
2097 memset(cmd, 0, sizeof(cmd));
2098 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
2099
2100 /*
2101 * Use MODE SELECT(10) if the device asked for it or if the mode page
2102 * and the mode select header cannot fit within the maximumm 255 bytes
2103 * of the MODE SELECT(6) command.
2104 */
2105 if (sdev->use_10_for_ms ||
2106 len + 4 > 255 ||
2107 data->block_descriptor_length > 255) {
2108 if (len > 65535 - 8)
2109 return -EINVAL;
2110 real_buffer = kmalloc(8 + len, GFP_KERNEL);
2111 if (!real_buffer)
2112 return -ENOMEM;
2113 memcpy(real_buffer + 8, buffer, len);
2114 len += 8;
2115 real_buffer[0] = 0;
2116 real_buffer[1] = 0;
2117 real_buffer[2] = data->medium_type;
2118 real_buffer[3] = data->device_specific;
2119 real_buffer[4] = data->longlba ? 0x01 : 0;
2120 real_buffer[5] = 0;
2121 put_unaligned_be16(data->block_descriptor_length,
2122 &real_buffer[6]);
2123
2124 cmd[0] = MODE_SELECT_10;
2125 put_unaligned_be16(len, &cmd[7]);
2126 } else {
2127 if (data->longlba)
2128 return -EINVAL;
2129
2130 real_buffer = kmalloc(4 + len, GFP_KERNEL);
2131 if (!real_buffer)
2132 return -ENOMEM;
2133 memcpy(real_buffer + 4, buffer, len);
2134 len += 4;
2135 real_buffer[0] = 0;
2136 real_buffer[1] = data->medium_type;
2137 real_buffer[2] = data->device_specific;
2138 real_buffer[3] = data->block_descriptor_length;
2139
2140 cmd[0] = MODE_SELECT;
2141 cmd[4] = len;
2142 }
2143
2144 ret = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_OUT, real_buffer, len,
2145 timeout, retries, &exec_args);
2146 kfree(real_buffer);
2147 return ret;
2148}
2149EXPORT_SYMBOL_GPL(scsi_mode_select);
2150
2151/**
2152 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
2153 * @sdev: SCSI device to be queried
2154 * @dbd: set to prevent mode sense from returning block descriptors
2155 * @modepage: mode page being requested
2156 * @subpage: sub-page of the mode page being requested
2157 * @buffer: request buffer (may not be smaller than eight bytes)
2158 * @len: length of request buffer.
2159 * @timeout: command timeout
2160 * @retries: number of retries before failing
2161 * @data: returns a structure abstracting the mode header data
2162 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2163 * must be SCSI_SENSE_BUFFERSIZE big.
2164 *
2165 * Returns zero if successful, or a negative error number on failure
2166 */
2167int
2168scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, int subpage,
2169 unsigned char *buffer, int len, int timeout, int retries,
2170 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2171{
2172 unsigned char cmd[12];
2173 int use_10_for_ms;
2174 int header_length;
2175 int result, retry_count = retries;
2176 struct scsi_sense_hdr my_sshdr;
2177 const struct scsi_exec_args exec_args = {
2178 /* caller might not be interested in sense, but we need it */
2179 .sshdr = sshdr ? : &my_sshdr,
2180 };
2181
2182 memset(data, 0, sizeof(*data));
2183 memset(&cmd[0], 0, 12);
2184
2185 dbd = sdev->set_dbd_for_ms ? 8 : dbd;
2186 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
2187 cmd[2] = modepage;
2188 cmd[3] = subpage;
2189
2190 sshdr = exec_args.sshdr;
2191
2192 retry:
2193 use_10_for_ms = sdev->use_10_for_ms || len > 255;
2194
2195 if (use_10_for_ms) {
2196 if (len < 8 || len > 65535)
2197 return -EINVAL;
2198
2199 cmd[0] = MODE_SENSE_10;
2200 put_unaligned_be16(len, &cmd[7]);
2201 header_length = 8;
2202 } else {
2203 if (len < 4)
2204 return -EINVAL;
2205
2206 cmd[0] = MODE_SENSE;
2207 cmd[4] = len;
2208 header_length = 4;
2209 }
2210
2211 memset(buffer, 0, len);
2212
2213 result = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_IN, buffer, len,
2214 timeout, retries, &exec_args);
2215 if (result < 0)
2216 return result;
2217
2218 /* This code looks awful: what it's doing is making sure an
2219 * ILLEGAL REQUEST sense return identifies the actual command
2220 * byte as the problem. MODE_SENSE commands can return
2221 * ILLEGAL REQUEST if the code page isn't supported */
2222
2223 if (!scsi_status_is_good(result)) {
2224 if (scsi_sense_valid(sshdr)) {
2225 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
2226 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
2227 /*
2228 * Invalid command operation code: retry using
2229 * MODE SENSE(6) if this was a MODE SENSE(10)
2230 * request, except if the request mode page is
2231 * too large for MODE SENSE single byte
2232 * allocation length field.
2233 */
2234 if (use_10_for_ms) {
2235 if (len > 255)
2236 return -EIO;
2237 sdev->use_10_for_ms = 0;
2238 goto retry;
2239 }
2240 }
2241 if (scsi_status_is_check_condition(result) &&
2242 sshdr->sense_key == UNIT_ATTENTION &&
2243 retry_count) {
2244 retry_count--;
2245 goto retry;
2246 }
2247 }
2248 return -EIO;
2249 }
2250 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
2251 (modepage == 6 || modepage == 8))) {
2252 /* Initio breakage? */
2253 header_length = 0;
2254 data->length = 13;
2255 data->medium_type = 0;
2256 data->device_specific = 0;
2257 data->longlba = 0;
2258 data->block_descriptor_length = 0;
2259 } else if (use_10_for_ms) {
2260 data->length = get_unaligned_be16(&buffer[0]) + 2;
2261 data->medium_type = buffer[2];
2262 data->device_specific = buffer[3];
2263 data->longlba = buffer[4] & 0x01;
2264 data->block_descriptor_length = get_unaligned_be16(&buffer[6]);
2265 } else {
2266 data->length = buffer[0] + 1;
2267 data->medium_type = buffer[1];
2268 data->device_specific = buffer[2];
2269 data->block_descriptor_length = buffer[3];
2270 }
2271 data->header_length = header_length;
2272
2273 return 0;
2274}
2275EXPORT_SYMBOL(scsi_mode_sense);
2276
2277/**
2278 * scsi_test_unit_ready - test if unit is ready
2279 * @sdev: scsi device to change the state of.
2280 * @timeout: command timeout
2281 * @retries: number of retries before failing
2282 * @sshdr: outpout pointer for decoded sense information.
2283 *
2284 * Returns zero if unsuccessful or an error if TUR failed. For
2285 * removable media, UNIT_ATTENTION sets ->changed flag.
2286 **/
2287int
2288scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2289 struct scsi_sense_hdr *sshdr)
2290{
2291 char cmd[] = {
2292 TEST_UNIT_READY, 0, 0, 0, 0, 0,
2293 };
2294 const struct scsi_exec_args exec_args = {
2295 .sshdr = sshdr,
2296 };
2297 int result;
2298
2299 /* try to eat the UNIT_ATTENTION if there are enough retries */
2300 do {
2301 result = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_IN, NULL, 0,
2302 timeout, 1, &exec_args);
2303 if (sdev->removable && result > 0 && scsi_sense_valid(sshdr) &&
2304 sshdr->sense_key == UNIT_ATTENTION)
2305 sdev->changed = 1;
2306 } while (result > 0 && scsi_sense_valid(sshdr) &&
2307 sshdr->sense_key == UNIT_ATTENTION && --retries);
2308
2309 return result;
2310}
2311EXPORT_SYMBOL(scsi_test_unit_ready);
2312
2313/**
2314 * scsi_device_set_state - Take the given device through the device state model.
2315 * @sdev: scsi device to change the state of.
2316 * @state: state to change to.
2317 *
2318 * Returns zero if successful or an error if the requested
2319 * transition is illegal.
2320 */
2321int
2322scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2323{
2324 enum scsi_device_state oldstate = sdev->sdev_state;
2325
2326 if (state == oldstate)
2327 return 0;
2328
2329 switch (state) {
2330 case SDEV_CREATED:
2331 switch (oldstate) {
2332 case SDEV_CREATED_BLOCK:
2333 break;
2334 default:
2335 goto illegal;
2336 }
2337 break;
2338
2339 case SDEV_RUNNING:
2340 switch (oldstate) {
2341 case SDEV_CREATED:
2342 case SDEV_OFFLINE:
2343 case SDEV_TRANSPORT_OFFLINE:
2344 case SDEV_QUIESCE:
2345 case SDEV_BLOCK:
2346 break;
2347 default:
2348 goto illegal;
2349 }
2350 break;
2351
2352 case SDEV_QUIESCE:
2353 switch (oldstate) {
2354 case SDEV_RUNNING:
2355 case SDEV_OFFLINE:
2356 case SDEV_TRANSPORT_OFFLINE:
2357 break;
2358 default:
2359 goto illegal;
2360 }
2361 break;
2362
2363 case SDEV_OFFLINE:
2364 case SDEV_TRANSPORT_OFFLINE:
2365 switch (oldstate) {
2366 case SDEV_CREATED:
2367 case SDEV_RUNNING:
2368 case SDEV_QUIESCE:
2369 case SDEV_BLOCK:
2370 break;
2371 default:
2372 goto illegal;
2373 }
2374 break;
2375
2376 case SDEV_BLOCK:
2377 switch (oldstate) {
2378 case SDEV_RUNNING:
2379 case SDEV_CREATED_BLOCK:
2380 case SDEV_QUIESCE:
2381 case SDEV_OFFLINE:
2382 break;
2383 default:
2384 goto illegal;
2385 }
2386 break;
2387
2388 case SDEV_CREATED_BLOCK:
2389 switch (oldstate) {
2390 case SDEV_CREATED:
2391 break;
2392 default:
2393 goto illegal;
2394 }
2395 break;
2396
2397 case SDEV_CANCEL:
2398 switch (oldstate) {
2399 case SDEV_CREATED:
2400 case SDEV_RUNNING:
2401 case SDEV_QUIESCE:
2402 case SDEV_OFFLINE:
2403 case SDEV_TRANSPORT_OFFLINE:
2404 break;
2405 default:
2406 goto illegal;
2407 }
2408 break;
2409
2410 case SDEV_DEL:
2411 switch (oldstate) {
2412 case SDEV_CREATED:
2413 case SDEV_RUNNING:
2414 case SDEV_OFFLINE:
2415 case SDEV_TRANSPORT_OFFLINE:
2416 case SDEV_CANCEL:
2417 case SDEV_BLOCK:
2418 case SDEV_CREATED_BLOCK:
2419 break;
2420 default:
2421 goto illegal;
2422 }
2423 break;
2424
2425 }
2426 sdev->offline_already = false;
2427 sdev->sdev_state = state;
2428 return 0;
2429
2430 illegal:
2431 SCSI_LOG_ERROR_RECOVERY(1,
2432 sdev_printk(KERN_ERR, sdev,
2433 "Illegal state transition %s->%s",
2434 scsi_device_state_name(oldstate),
2435 scsi_device_state_name(state))
2436 );
2437 return -EINVAL;
2438}
2439EXPORT_SYMBOL(scsi_device_set_state);
2440
2441/**
2442 * scsi_evt_emit - emit a single SCSI device uevent
2443 * @sdev: associated SCSI device
2444 * @evt: event to emit
2445 *
2446 * Send a single uevent (scsi_event) to the associated scsi_device.
2447 */
2448static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2449{
2450 int idx = 0;
2451 char *envp[3];
2452
2453 switch (evt->evt_type) {
2454 case SDEV_EVT_MEDIA_CHANGE:
2455 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2456 break;
2457 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2458 scsi_rescan_device(sdev);
2459 envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2460 break;
2461 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2462 envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2463 break;
2464 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2465 envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2466 break;
2467 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2468 envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2469 break;
2470 case SDEV_EVT_LUN_CHANGE_REPORTED:
2471 envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2472 break;
2473 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2474 envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
2475 break;
2476 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2477 envp[idx++] = "SDEV_UA=POWER_ON_RESET_OCCURRED";
2478 break;
2479 default:
2480 /* do nothing */
2481 break;
2482 }
2483
2484 envp[idx++] = NULL;
2485
2486 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2487}
2488
2489/**
2490 * scsi_evt_thread - send a uevent for each scsi event
2491 * @work: work struct for scsi_device
2492 *
2493 * Dispatch queued events to their associated scsi_device kobjects
2494 * as uevents.
2495 */
2496void scsi_evt_thread(struct work_struct *work)
2497{
2498 struct scsi_device *sdev;
2499 enum scsi_device_event evt_type;
2500 LIST_HEAD(event_list);
2501
2502 sdev = container_of(work, struct scsi_device, event_work);
2503
2504 for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
2505 if (test_and_clear_bit(evt_type, sdev->pending_events))
2506 sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
2507
2508 while (1) {
2509 struct scsi_event *evt;
2510 struct list_head *this, *tmp;
2511 unsigned long flags;
2512
2513 spin_lock_irqsave(&sdev->list_lock, flags);
2514 list_splice_init(&sdev->event_list, &event_list);
2515 spin_unlock_irqrestore(&sdev->list_lock, flags);
2516
2517 if (list_empty(&event_list))
2518 break;
2519
2520 list_for_each_safe(this, tmp, &event_list) {
2521 evt = list_entry(this, struct scsi_event, node);
2522 list_del(&evt->node);
2523 scsi_evt_emit(sdev, evt);
2524 kfree(evt);
2525 }
2526 }
2527}
2528
2529/**
2530 * sdev_evt_send - send asserted event to uevent thread
2531 * @sdev: scsi_device event occurred on
2532 * @evt: event to send
2533 *
2534 * Assert scsi device event asynchronously.
2535 */
2536void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2537{
2538 unsigned long flags;
2539
2540#if 0
2541 /* FIXME: currently this check eliminates all media change events
2542 * for polled devices. Need to update to discriminate between AN
2543 * and polled events */
2544 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2545 kfree(evt);
2546 return;
2547 }
2548#endif
2549
2550 spin_lock_irqsave(&sdev->list_lock, flags);
2551 list_add_tail(&evt->node, &sdev->event_list);
2552 schedule_work(&sdev->event_work);
2553 spin_unlock_irqrestore(&sdev->list_lock, flags);
2554}
2555EXPORT_SYMBOL_GPL(sdev_evt_send);
2556
2557/**
2558 * sdev_evt_alloc - allocate a new scsi event
2559 * @evt_type: type of event to allocate
2560 * @gfpflags: GFP flags for allocation
2561 *
2562 * Allocates and returns a new scsi_event.
2563 */
2564struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2565 gfp_t gfpflags)
2566{
2567 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2568 if (!evt)
2569 return NULL;
2570
2571 evt->evt_type = evt_type;
2572 INIT_LIST_HEAD(&evt->node);
2573
2574 /* evt_type-specific initialization, if any */
2575 switch (evt_type) {
2576 case SDEV_EVT_MEDIA_CHANGE:
2577 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2578 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2579 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2580 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2581 case SDEV_EVT_LUN_CHANGE_REPORTED:
2582 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2583 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2584 default:
2585 /* do nothing */
2586 break;
2587 }
2588
2589 return evt;
2590}
2591EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2592
2593/**
2594 * sdev_evt_send_simple - send asserted event to uevent thread
2595 * @sdev: scsi_device event occurred on
2596 * @evt_type: type of event to send
2597 * @gfpflags: GFP flags for allocation
2598 *
2599 * Assert scsi device event asynchronously, given an event type.
2600 */
2601void sdev_evt_send_simple(struct scsi_device *sdev,
2602 enum scsi_device_event evt_type, gfp_t gfpflags)
2603{
2604 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2605 if (!evt) {
2606 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2607 evt_type);
2608 return;
2609 }
2610
2611 sdev_evt_send(sdev, evt);
2612}
2613EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2614
2615/**
2616 * scsi_device_quiesce - Block all commands except power management.
2617 * @sdev: scsi device to quiesce.
2618 *
2619 * This works by trying to transition to the SDEV_QUIESCE state
2620 * (which must be a legal transition). When the device is in this
2621 * state, only power management requests will be accepted, all others will
2622 * be deferred.
2623 *
2624 * Must be called with user context, may sleep.
2625 *
2626 * Returns zero if unsuccessful or an error if not.
2627 */
2628int
2629scsi_device_quiesce(struct scsi_device *sdev)
2630{
2631 struct request_queue *q = sdev->request_queue;
2632 int err;
2633
2634 /*
2635 * It is allowed to call scsi_device_quiesce() multiple times from
2636 * the same context but concurrent scsi_device_quiesce() calls are
2637 * not allowed.
2638 */
2639 WARN_ON_ONCE(sdev->quiesced_by && sdev->quiesced_by != current);
2640
2641 if (sdev->quiesced_by == current)
2642 return 0;
2643
2644 blk_set_pm_only(q);
2645
2646 blk_mq_freeze_queue(q);
2647 /*
2648 * Ensure that the effect of blk_set_pm_only() will be visible
2649 * for percpu_ref_tryget() callers that occur after the queue
2650 * unfreeze even if the queue was already frozen before this function
2651 * was called. See also https://lwn.net/Articles/573497/.
2652 */
2653 synchronize_rcu();
2654 blk_mq_unfreeze_queue(q);
2655
2656 mutex_lock(&sdev->state_mutex);
2657 err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2658 if (err == 0)
2659 sdev->quiesced_by = current;
2660 else
2661 blk_clear_pm_only(q);
2662 mutex_unlock(&sdev->state_mutex);
2663
2664 return err;
2665}
2666EXPORT_SYMBOL(scsi_device_quiesce);
2667
2668/**
2669 * scsi_device_resume - Restart user issued commands to a quiesced device.
2670 * @sdev: scsi device to resume.
2671 *
2672 * Moves the device from quiesced back to running and restarts the
2673 * queues.
2674 *
2675 * Must be called with user context, may sleep.
2676 */
2677void scsi_device_resume(struct scsi_device *sdev)
2678{
2679 /* check if the device state was mutated prior to resume, and if
2680 * so assume the state is being managed elsewhere (for example
2681 * device deleted during suspend)
2682 */
2683 mutex_lock(&sdev->state_mutex);
2684 if (sdev->sdev_state == SDEV_QUIESCE)
2685 scsi_device_set_state(sdev, SDEV_RUNNING);
2686 if (sdev->quiesced_by) {
2687 sdev->quiesced_by = NULL;
2688 blk_clear_pm_only(sdev->request_queue);
2689 }
2690 mutex_unlock(&sdev->state_mutex);
2691}
2692EXPORT_SYMBOL(scsi_device_resume);
2693
2694static void
2695device_quiesce_fn(struct scsi_device *sdev, void *data)
2696{
2697 scsi_device_quiesce(sdev);
2698}
2699
2700void
2701scsi_target_quiesce(struct scsi_target *starget)
2702{
2703 starget_for_each_device(starget, NULL, device_quiesce_fn);
2704}
2705EXPORT_SYMBOL(scsi_target_quiesce);
2706
2707static void
2708device_resume_fn(struct scsi_device *sdev, void *data)
2709{
2710 scsi_device_resume(sdev);
2711}
2712
2713void
2714scsi_target_resume(struct scsi_target *starget)
2715{
2716 starget_for_each_device(starget, NULL, device_resume_fn);
2717}
2718EXPORT_SYMBOL(scsi_target_resume);
2719
2720static int __scsi_internal_device_block_nowait(struct scsi_device *sdev)
2721{
2722 if (scsi_device_set_state(sdev, SDEV_BLOCK))
2723 return scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2724
2725 return 0;
2726}
2727
2728void scsi_start_queue(struct scsi_device *sdev)
2729{
2730 if (cmpxchg(&sdev->queue_stopped, 1, 0))
2731 blk_mq_unquiesce_queue(sdev->request_queue);
2732}
2733
2734static void scsi_stop_queue(struct scsi_device *sdev)
2735{
2736 /*
2737 * The atomic variable of ->queue_stopped covers that
2738 * blk_mq_quiesce_queue* is balanced with blk_mq_unquiesce_queue.
2739 *
2740 * The caller needs to wait until quiesce is done.
2741 */
2742 if (!cmpxchg(&sdev->queue_stopped, 0, 1))
2743 blk_mq_quiesce_queue_nowait(sdev->request_queue);
2744}
2745
2746/**
2747 * scsi_internal_device_block_nowait - try to transition to the SDEV_BLOCK state
2748 * @sdev: device to block
2749 *
2750 * Pause SCSI command processing on the specified device. Does not sleep.
2751 *
2752 * Returns zero if successful or a negative error code upon failure.
2753 *
2754 * Notes:
2755 * This routine transitions the device to the SDEV_BLOCK state (which must be
2756 * a legal transition). When the device is in this state, command processing
2757 * is paused until the device leaves the SDEV_BLOCK state. See also
2758 * scsi_internal_device_unblock_nowait().
2759 */
2760int scsi_internal_device_block_nowait(struct scsi_device *sdev)
2761{
2762 int ret = __scsi_internal_device_block_nowait(sdev);
2763
2764 /*
2765 * The device has transitioned to SDEV_BLOCK. Stop the
2766 * block layer from calling the midlayer with this device's
2767 * request queue.
2768 */
2769 if (!ret)
2770 scsi_stop_queue(sdev);
2771 return ret;
2772}
2773EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait);
2774
2775/**
2776 * scsi_device_block - try to transition to the SDEV_BLOCK state
2777 * @sdev: device to block
2778 * @data: dummy argument, ignored
2779 *
2780 * Pause SCSI command processing on the specified device. Callers must wait
2781 * until all ongoing scsi_queue_rq() calls have finished after this function
2782 * returns.
2783 *
2784 * Note:
2785 * This routine transitions the device to the SDEV_BLOCK state (which must be
2786 * a legal transition). When the device is in this state, command processing
2787 * is paused until the device leaves the SDEV_BLOCK state. See also
2788 * scsi_internal_device_unblock().
2789 */
2790static void scsi_device_block(struct scsi_device *sdev, void *data)
2791{
2792 int err;
2793 enum scsi_device_state state;
2794
2795 mutex_lock(&sdev->state_mutex);
2796 err = __scsi_internal_device_block_nowait(sdev);
2797 state = sdev->sdev_state;
2798 if (err == 0)
2799 /*
2800 * scsi_stop_queue() must be called with the state_mutex
2801 * held. Otherwise a simultaneous scsi_start_queue() call
2802 * might unquiesce the queue before we quiesce it.
2803 */
2804 scsi_stop_queue(sdev);
2805
2806 mutex_unlock(&sdev->state_mutex);
2807
2808 WARN_ONCE(err, "%s: failed to block %s in state %d\n",
2809 __func__, dev_name(&sdev->sdev_gendev), state);
2810}
2811
2812/**
2813 * scsi_internal_device_unblock_nowait - resume a device after a block request
2814 * @sdev: device to resume
2815 * @new_state: state to set the device to after unblocking
2816 *
2817 * Restart the device queue for a previously suspended SCSI device. Does not
2818 * sleep.
2819 *
2820 * Returns zero if successful or a negative error code upon failure.
2821 *
2822 * Notes:
2823 * This routine transitions the device to the SDEV_RUNNING state or to one of
2824 * the offline states (which must be a legal transition) allowing the midlayer
2825 * to goose the queue for this device.
2826 */
2827int scsi_internal_device_unblock_nowait(struct scsi_device *sdev,
2828 enum scsi_device_state new_state)
2829{
2830 switch (new_state) {
2831 case SDEV_RUNNING:
2832 case SDEV_TRANSPORT_OFFLINE:
2833 break;
2834 default:
2835 return -EINVAL;
2836 }
2837
2838 /*
2839 * Try to transition the scsi device to SDEV_RUNNING or one of the
2840 * offlined states and goose the device queue if successful.
2841 */
2842 switch (sdev->sdev_state) {
2843 case SDEV_BLOCK:
2844 case SDEV_TRANSPORT_OFFLINE:
2845 sdev->sdev_state = new_state;
2846 break;
2847 case SDEV_CREATED_BLOCK:
2848 if (new_state == SDEV_TRANSPORT_OFFLINE ||
2849 new_state == SDEV_OFFLINE)
2850 sdev->sdev_state = new_state;
2851 else
2852 sdev->sdev_state = SDEV_CREATED;
2853 break;
2854 case SDEV_CANCEL:
2855 case SDEV_OFFLINE:
2856 break;
2857 default:
2858 return -EINVAL;
2859 }
2860 scsi_start_queue(sdev);
2861
2862 return 0;
2863}
2864EXPORT_SYMBOL_GPL(scsi_internal_device_unblock_nowait);
2865
2866/**
2867 * scsi_internal_device_unblock - resume a device after a block request
2868 * @sdev: device to resume
2869 * @new_state: state to set the device to after unblocking
2870 *
2871 * Restart the device queue for a previously suspended SCSI device. May sleep.
2872 *
2873 * Returns zero if successful or a negative error code upon failure.
2874 *
2875 * Notes:
2876 * This routine transitions the device to the SDEV_RUNNING state or to one of
2877 * the offline states (which must be a legal transition) allowing the midlayer
2878 * to goose the queue for this device.
2879 */
2880static int scsi_internal_device_unblock(struct scsi_device *sdev,
2881 enum scsi_device_state new_state)
2882{
2883 int ret;
2884
2885 mutex_lock(&sdev->state_mutex);
2886 ret = scsi_internal_device_unblock_nowait(sdev, new_state);
2887 mutex_unlock(&sdev->state_mutex);
2888
2889 return ret;
2890}
2891
2892static int
2893target_block(struct device *dev, void *data)
2894{
2895 if (scsi_is_target_device(dev))
2896 starget_for_each_device(to_scsi_target(dev), NULL,
2897 scsi_device_block);
2898 return 0;
2899}
2900
2901/**
2902 * scsi_block_targets - transition all SCSI child devices to SDEV_BLOCK state
2903 * @dev: a parent device of one or more scsi_target devices
2904 * @shost: the Scsi_Host to which this device belongs
2905 *
2906 * Iterate over all children of @dev, which should be scsi_target devices,
2907 * and switch all subordinate scsi devices to SDEV_BLOCK state. Wait for
2908 * ongoing scsi_queue_rq() calls to finish. May sleep.
2909 *
2910 * Note:
2911 * @dev must not itself be a scsi_target device.
2912 */
2913void
2914scsi_block_targets(struct Scsi_Host *shost, struct device *dev)
2915{
2916 WARN_ON_ONCE(scsi_is_target_device(dev));
2917 device_for_each_child(dev, NULL, target_block);
2918 blk_mq_wait_quiesce_done(&shost->tag_set);
2919}
2920EXPORT_SYMBOL_GPL(scsi_block_targets);
2921
2922static void
2923device_unblock(struct scsi_device *sdev, void *data)
2924{
2925 scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
2926}
2927
2928static int
2929target_unblock(struct device *dev, void *data)
2930{
2931 if (scsi_is_target_device(dev))
2932 starget_for_each_device(to_scsi_target(dev), data,
2933 device_unblock);
2934 return 0;
2935}
2936
2937void
2938scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
2939{
2940 if (scsi_is_target_device(dev))
2941 starget_for_each_device(to_scsi_target(dev), &new_state,
2942 device_unblock);
2943 else
2944 device_for_each_child(dev, &new_state, target_unblock);
2945}
2946EXPORT_SYMBOL_GPL(scsi_target_unblock);
2947
2948/**
2949 * scsi_host_block - Try to transition all logical units to the SDEV_BLOCK state
2950 * @shost: device to block
2951 *
2952 * Pause SCSI command processing for all logical units associated with the SCSI
2953 * host and wait until pending scsi_queue_rq() calls have finished.
2954 *
2955 * Returns zero if successful or a negative error code upon failure.
2956 */
2957int
2958scsi_host_block(struct Scsi_Host *shost)
2959{
2960 struct scsi_device *sdev;
2961 int ret;
2962
2963 /*
2964 * Call scsi_internal_device_block_nowait so we can avoid
2965 * calling synchronize_rcu() for each LUN.
2966 */
2967 shost_for_each_device(sdev, shost) {
2968 mutex_lock(&sdev->state_mutex);
2969 ret = scsi_internal_device_block_nowait(sdev);
2970 mutex_unlock(&sdev->state_mutex);
2971 if (ret) {
2972 scsi_device_put(sdev);
2973 return ret;
2974 }
2975 }
2976
2977 /* Wait for ongoing scsi_queue_rq() calls to finish. */
2978 blk_mq_wait_quiesce_done(&shost->tag_set);
2979
2980 return 0;
2981}
2982EXPORT_SYMBOL_GPL(scsi_host_block);
2983
2984int
2985scsi_host_unblock(struct Scsi_Host *shost, int new_state)
2986{
2987 struct scsi_device *sdev;
2988 int ret = 0;
2989
2990 shost_for_each_device(sdev, shost) {
2991 ret = scsi_internal_device_unblock(sdev, new_state);
2992 if (ret) {
2993 scsi_device_put(sdev);
2994 break;
2995 }
2996 }
2997 return ret;
2998}
2999EXPORT_SYMBOL_GPL(scsi_host_unblock);
3000
3001/**
3002 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
3003 * @sgl: scatter-gather list
3004 * @sg_count: number of segments in sg
3005 * @offset: offset in bytes into sg, on return offset into the mapped area
3006 * @len: bytes to map, on return number of bytes mapped
3007 *
3008 * Returns virtual address of the start of the mapped page
3009 */
3010void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
3011 size_t *offset, size_t *len)
3012{
3013 int i;
3014 size_t sg_len = 0, len_complete = 0;
3015 struct scatterlist *sg;
3016 struct page *page;
3017
3018 WARN_ON(!irqs_disabled());
3019
3020 for_each_sg(sgl, sg, sg_count, i) {
3021 len_complete = sg_len; /* Complete sg-entries */
3022 sg_len += sg->length;
3023 if (sg_len > *offset)
3024 break;
3025 }
3026
3027 if (unlikely(i == sg_count)) {
3028 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
3029 "elements %d\n",
3030 __func__, sg_len, *offset, sg_count);
3031 WARN_ON(1);
3032 return NULL;
3033 }
3034
3035 /* Offset starting from the beginning of first page in this sg-entry */
3036 *offset = *offset - len_complete + sg->offset;
3037
3038 /* Assumption: contiguous pages can be accessed as "page + i" */
3039 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
3040 *offset &= ~PAGE_MASK;
3041
3042 /* Bytes in this sg-entry from *offset to the end of the page */
3043 sg_len = PAGE_SIZE - *offset;
3044 if (*len > sg_len)
3045 *len = sg_len;
3046
3047 return kmap_atomic(page);
3048}
3049EXPORT_SYMBOL(scsi_kmap_atomic_sg);
3050
3051/**
3052 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
3053 * @virt: virtual address to be unmapped
3054 */
3055void scsi_kunmap_atomic_sg(void *virt)
3056{
3057 kunmap_atomic(virt);
3058}
3059EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
3060
3061void sdev_disable_disk_events(struct scsi_device *sdev)
3062{
3063 atomic_inc(&sdev->disk_events_disable_depth);
3064}
3065EXPORT_SYMBOL(sdev_disable_disk_events);
3066
3067void sdev_enable_disk_events(struct scsi_device *sdev)
3068{
3069 if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0))
3070 return;
3071 atomic_dec(&sdev->disk_events_disable_depth);
3072}
3073EXPORT_SYMBOL(sdev_enable_disk_events);
3074
3075static unsigned char designator_prio(const unsigned char *d)
3076{
3077 if (d[1] & 0x30)
3078 /* not associated with LUN */
3079 return 0;
3080
3081 if (d[3] == 0)
3082 /* invalid length */
3083 return 0;
3084
3085 /*
3086 * Order of preference for lun descriptor:
3087 * - SCSI name string
3088 * - NAA IEEE Registered Extended
3089 * - EUI-64 based 16-byte
3090 * - EUI-64 based 12-byte
3091 * - NAA IEEE Registered
3092 * - NAA IEEE Extended
3093 * - EUI-64 based 8-byte
3094 * - SCSI name string (truncated)
3095 * - T10 Vendor ID
3096 * as longer descriptors reduce the likelyhood
3097 * of identification clashes.
3098 */
3099
3100 switch (d[1] & 0xf) {
3101 case 8:
3102 /* SCSI name string, variable-length UTF-8 */
3103 return 9;
3104 case 3:
3105 switch (d[4] >> 4) {
3106 case 6:
3107 /* NAA registered extended */
3108 return 8;
3109 case 5:
3110 /* NAA registered */
3111 return 5;
3112 case 4:
3113 /* NAA extended */
3114 return 4;
3115 case 3:
3116 /* NAA locally assigned */
3117 return 1;
3118 default:
3119 break;
3120 }
3121 break;
3122 case 2:
3123 switch (d[3]) {
3124 case 16:
3125 /* EUI64-based, 16 byte */
3126 return 7;
3127 case 12:
3128 /* EUI64-based, 12 byte */
3129 return 6;
3130 case 8:
3131 /* EUI64-based, 8 byte */
3132 return 3;
3133 default:
3134 break;
3135 }
3136 break;
3137 case 1:
3138 /* T10 vendor ID */
3139 return 1;
3140 default:
3141 break;
3142 }
3143
3144 return 0;
3145}
3146
3147/**
3148 * scsi_vpd_lun_id - return a unique device identification
3149 * @sdev: SCSI device
3150 * @id: buffer for the identification
3151 * @id_len: length of the buffer
3152 *
3153 * Copies a unique device identification into @id based
3154 * on the information in the VPD page 0x83 of the device.
3155 * The string will be formatted as a SCSI name string.
3156 *
3157 * Returns the length of the identification or error on failure.
3158 * If the identifier is longer than the supplied buffer the actual
3159 * identifier length is returned and the buffer is not zero-padded.
3160 */
3161int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len)
3162{
3163 u8 cur_id_prio = 0;
3164 u8 cur_id_size = 0;
3165 const unsigned char *d, *cur_id_str;
3166 const struct scsi_vpd *vpd_pg83;
3167 int id_size = -EINVAL;
3168
3169 rcu_read_lock();
3170 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3171 if (!vpd_pg83) {
3172 rcu_read_unlock();
3173 return -ENXIO;
3174 }
3175
3176 /* The id string must be at least 20 bytes + terminating NULL byte */
3177 if (id_len < 21) {
3178 rcu_read_unlock();
3179 return -EINVAL;
3180 }
3181
3182 memset(id, 0, id_len);
3183 for (d = vpd_pg83->data + 4;
3184 d < vpd_pg83->data + vpd_pg83->len;
3185 d += d[3] + 4) {
3186 u8 prio = designator_prio(d);
3187
3188 if (prio == 0 || cur_id_prio > prio)
3189 continue;
3190
3191 switch (d[1] & 0xf) {
3192 case 0x1:
3193 /* T10 Vendor ID */
3194 if (cur_id_size > d[3])
3195 break;
3196 cur_id_prio = prio;
3197 cur_id_size = d[3];
3198 if (cur_id_size + 4 > id_len)
3199 cur_id_size = id_len - 4;
3200 cur_id_str = d + 4;
3201 id_size = snprintf(id, id_len, "t10.%*pE",
3202 cur_id_size, cur_id_str);
3203 break;
3204 case 0x2:
3205 /* EUI-64 */
3206 cur_id_prio = prio;
3207 cur_id_size = d[3];
3208 cur_id_str = d + 4;
3209 switch (cur_id_size) {
3210 case 8:
3211 id_size = snprintf(id, id_len,
3212 "eui.%8phN",
3213 cur_id_str);
3214 break;
3215 case 12:
3216 id_size = snprintf(id, id_len,
3217 "eui.%12phN",
3218 cur_id_str);
3219 break;
3220 case 16:
3221 id_size = snprintf(id, id_len,
3222 "eui.%16phN",
3223 cur_id_str);
3224 break;
3225 default:
3226 break;
3227 }
3228 break;
3229 case 0x3:
3230 /* NAA */
3231 cur_id_prio = prio;
3232 cur_id_size = d[3];
3233 cur_id_str = d + 4;
3234 switch (cur_id_size) {
3235 case 8:
3236 id_size = snprintf(id, id_len,
3237 "naa.%8phN",
3238 cur_id_str);
3239 break;
3240 case 16:
3241 id_size = snprintf(id, id_len,
3242 "naa.%16phN",
3243 cur_id_str);
3244 break;
3245 default:
3246 break;
3247 }
3248 break;
3249 case 0x8:
3250 /* SCSI name string */
3251 if (cur_id_size > d[3])
3252 break;
3253 /* Prefer others for truncated descriptor */
3254 if (d[3] > id_len) {
3255 prio = 2;
3256 if (cur_id_prio > prio)
3257 break;
3258 }
3259 cur_id_prio = prio;
3260 cur_id_size = id_size = d[3];
3261 cur_id_str = d + 4;
3262 if (cur_id_size >= id_len)
3263 cur_id_size = id_len - 1;
3264 memcpy(id, cur_id_str, cur_id_size);
3265 break;
3266 default:
3267 break;
3268 }
3269 }
3270 rcu_read_unlock();
3271
3272 return id_size;
3273}
3274EXPORT_SYMBOL(scsi_vpd_lun_id);
3275
3276/*
3277 * scsi_vpd_tpg_id - return a target port group identifier
3278 * @sdev: SCSI device
3279 *
3280 * Returns the Target Port Group identifier from the information
3281 * froom VPD page 0x83 of the device.
3282 *
3283 * Returns the identifier or error on failure.
3284 */
3285int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id)
3286{
3287 const unsigned char *d;
3288 const struct scsi_vpd *vpd_pg83;
3289 int group_id = -EAGAIN, rel_port = -1;
3290
3291 rcu_read_lock();
3292 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3293 if (!vpd_pg83) {
3294 rcu_read_unlock();
3295 return -ENXIO;
3296 }
3297
3298 d = vpd_pg83->data + 4;
3299 while (d < vpd_pg83->data + vpd_pg83->len) {
3300 switch (d[1] & 0xf) {
3301 case 0x4:
3302 /* Relative target port */
3303 rel_port = get_unaligned_be16(&d[6]);
3304 break;
3305 case 0x5:
3306 /* Target port group */
3307 group_id = get_unaligned_be16(&d[6]);
3308 break;
3309 default:
3310 break;
3311 }
3312 d += d[3] + 4;
3313 }
3314 rcu_read_unlock();
3315
3316 if (group_id >= 0 && rel_id && rel_port != -1)
3317 *rel_id = rel_port;
3318
3319 return group_id;
3320}
3321EXPORT_SYMBOL(scsi_vpd_tpg_id);
3322
3323/**
3324 * scsi_build_sense - build sense data for a command
3325 * @scmd: scsi command for which the sense should be formatted
3326 * @desc: Sense format (non-zero == descriptor format,
3327 * 0 == fixed format)
3328 * @key: Sense key
3329 * @asc: Additional sense code
3330 * @ascq: Additional sense code qualifier
3331 *
3332 **/
3333void scsi_build_sense(struct scsi_cmnd *scmd, int desc, u8 key, u8 asc, u8 ascq)
3334{
3335 scsi_build_sense_buffer(desc, scmd->sense_buffer, key, asc, ascq);
3336 scmd->result = SAM_STAT_CHECK_CONDITION;
3337}
3338EXPORT_SYMBOL_GPL(scsi_build_sense);
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 <linux/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_limits() */
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 (!scmd->result)
214 return 0;
215
216 if (!failures)
217 return 0;
218
219 for (failure = failures->failure_definitions; failure->result;
220 failure++) {
221 if (failure->result == SCMD_FAILURE_RESULT_ANY)
222 goto maybe_retry;
223
224 if (host_byte(scmd->result) &&
225 host_byte(scmd->result) == host_byte(failure->result))
226 goto maybe_retry;
227
228 status = status_byte(scmd->result);
229 if (!status)
230 continue;
231
232 if (failure->result == SCMD_FAILURE_STAT_ANY &&
233 !scsi_status_is_good(scmd->result))
234 goto maybe_retry;
235
236 if (status != status_byte(failure->result))
237 continue;
238
239 if (status_byte(failure->result) != SAM_STAT_CHECK_CONDITION ||
240 failure->sense == SCMD_FAILURE_SENSE_ANY)
241 goto maybe_retry;
242
243 if (!scsi_command_normalize_sense(scmd, &sshdr))
244 return 0;
245
246 if (failure->sense != sshdr.sense_key)
247 continue;
248
249 if (failure->asc == SCMD_FAILURE_ASC_ANY)
250 goto maybe_retry;
251
252 if (failure->asc != sshdr.asc)
253 continue;
254
255 if (failure->ascq == SCMD_FAILURE_ASCQ_ANY ||
256 failure->ascq == sshdr.ascq)
257 goto maybe_retry;
258 }
259
260 return 0;
261
262maybe_retry:
263 if (failure->allowed) {
264 if (failure->allowed == SCMD_FAILURE_NO_LIMIT ||
265 ++failure->retries <= failure->allowed)
266 return -EAGAIN;
267 } else {
268 if (failures->total_allowed == SCMD_FAILURE_NO_LIMIT ||
269 ++failures->total_retries <= failures->total_allowed)
270 return -EAGAIN;
271 }
272
273 return 0;
274}
275
276/**
277 * scsi_execute_cmd - insert request and wait for the result
278 * @sdev: scsi_device
279 * @cmd: scsi command
280 * @opf: block layer request cmd_flags
281 * @buffer: data buffer
282 * @bufflen: len of buffer
283 * @timeout: request timeout in HZ
284 * @ml_retries: number of times SCSI midlayer will retry request
285 * @args: Optional args. See struct definition for field descriptions
286 *
287 * Returns the scsi_cmnd result field if a command was executed, or a negative
288 * Linux error code if we didn't get that far.
289 */
290int scsi_execute_cmd(struct scsi_device *sdev, const unsigned char *cmd,
291 blk_opf_t opf, void *buffer, unsigned int bufflen,
292 int timeout, int ml_retries,
293 const struct scsi_exec_args *args)
294{
295 static const struct scsi_exec_args default_args;
296 struct request *req;
297 struct scsi_cmnd *scmd;
298 int ret;
299
300 if (!args)
301 args = &default_args;
302 else if (WARN_ON_ONCE(args->sense &&
303 args->sense_len != SCSI_SENSE_BUFFERSIZE))
304 return -EINVAL;
305
306retry:
307 req = scsi_alloc_request(sdev->request_queue, opf, args->req_flags);
308 if (IS_ERR(req))
309 return PTR_ERR(req);
310
311 if (bufflen) {
312 ret = blk_rq_map_kern(sdev->request_queue, req,
313 buffer, bufflen, GFP_NOIO);
314 if (ret)
315 goto out;
316 }
317 scmd = blk_mq_rq_to_pdu(req);
318 scmd->cmd_len = COMMAND_SIZE(cmd[0]);
319 memcpy(scmd->cmnd, cmd, scmd->cmd_len);
320 scmd->allowed = ml_retries;
321 scmd->flags |= args->scmd_flags;
322 req->timeout = timeout;
323 req->rq_flags |= RQF_QUIET;
324
325 /*
326 * head injection *required* here otherwise quiesce won't work
327 */
328 blk_execute_rq(req, true);
329
330 if (scsi_check_passthrough(scmd, args->failures) == -EAGAIN) {
331 blk_mq_free_request(req);
332 goto retry;
333 }
334
335 /*
336 * Some devices (USB mass-storage in particular) may transfer
337 * garbage data together with a residue indicating that the data
338 * is invalid. Prevent the garbage from being misinterpreted
339 * and prevent security leaks by zeroing out the excess data.
340 */
341 if (unlikely(scmd->resid_len > 0 && scmd->resid_len <= bufflen))
342 memset(buffer + bufflen - scmd->resid_len, 0, scmd->resid_len);
343
344 if (args->resid)
345 *args->resid = scmd->resid_len;
346 if (args->sense)
347 memcpy(args->sense, scmd->sense_buffer, SCSI_SENSE_BUFFERSIZE);
348 if (args->sshdr)
349 scsi_normalize_sense(scmd->sense_buffer, scmd->sense_len,
350 args->sshdr);
351
352 ret = scmd->result;
353 out:
354 blk_mq_free_request(req);
355
356 return ret;
357}
358EXPORT_SYMBOL(scsi_execute_cmd);
359
360/*
361 * Wake up the error handler if necessary. Avoid as follows that the error
362 * handler is not woken up if host in-flight requests number ==
363 * shost->host_failed: use call_rcu() in scsi_eh_scmd_add() in combination
364 * with an RCU read lock in this function to ensure that this function in
365 * its entirety either finishes before scsi_eh_scmd_add() increases the
366 * host_failed counter or that it notices the shost state change made by
367 * scsi_eh_scmd_add().
368 */
369static void scsi_dec_host_busy(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
370{
371 unsigned long flags;
372
373 rcu_read_lock();
374 __clear_bit(SCMD_STATE_INFLIGHT, &cmd->state);
375 if (unlikely(scsi_host_in_recovery(shost))) {
376 unsigned int busy = scsi_host_busy(shost);
377
378 spin_lock_irqsave(shost->host_lock, flags);
379 if (shost->host_failed || shost->host_eh_scheduled)
380 scsi_eh_wakeup(shost, busy);
381 spin_unlock_irqrestore(shost->host_lock, flags);
382 }
383 rcu_read_unlock();
384}
385
386void scsi_device_unbusy(struct scsi_device *sdev, struct scsi_cmnd *cmd)
387{
388 struct Scsi_Host *shost = sdev->host;
389 struct scsi_target *starget = scsi_target(sdev);
390
391 scsi_dec_host_busy(shost, cmd);
392
393 if (starget->can_queue > 0)
394 atomic_dec(&starget->target_busy);
395
396 sbitmap_put(&sdev->budget_map, cmd->budget_token);
397 cmd->budget_token = -1;
398}
399
400/*
401 * Kick the queue of SCSI device @sdev if @sdev != current_sdev. Called with
402 * interrupts disabled.
403 */
404static void scsi_kick_sdev_queue(struct scsi_device *sdev, void *data)
405{
406 struct scsi_device *current_sdev = data;
407
408 if (sdev != current_sdev)
409 blk_mq_run_hw_queues(sdev->request_queue, true);
410}
411
412/*
413 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
414 * and call blk_run_queue for all the scsi_devices on the target -
415 * including current_sdev first.
416 *
417 * Called with *no* scsi locks held.
418 */
419static void scsi_single_lun_run(struct scsi_device *current_sdev)
420{
421 struct Scsi_Host *shost = current_sdev->host;
422 struct scsi_target *starget = scsi_target(current_sdev);
423 unsigned long flags;
424
425 spin_lock_irqsave(shost->host_lock, flags);
426 starget->starget_sdev_user = NULL;
427 spin_unlock_irqrestore(shost->host_lock, flags);
428
429 /*
430 * Call blk_run_queue for all LUNs on the target, starting with
431 * current_sdev. We race with others (to set starget_sdev_user),
432 * but in most cases, we will be first. Ideally, each LU on the
433 * target would get some limited time or requests on the target.
434 */
435 blk_mq_run_hw_queues(current_sdev->request_queue,
436 shost->queuecommand_may_block);
437
438 spin_lock_irqsave(shost->host_lock, flags);
439 if (!starget->starget_sdev_user)
440 __starget_for_each_device(starget, current_sdev,
441 scsi_kick_sdev_queue);
442 spin_unlock_irqrestore(shost->host_lock, flags);
443}
444
445static inline bool scsi_device_is_busy(struct scsi_device *sdev)
446{
447 if (scsi_device_busy(sdev) >= sdev->queue_depth)
448 return true;
449 if (atomic_read(&sdev->device_blocked) > 0)
450 return true;
451 return false;
452}
453
454static inline bool scsi_target_is_busy(struct scsi_target *starget)
455{
456 if (starget->can_queue > 0) {
457 if (atomic_read(&starget->target_busy) >= starget->can_queue)
458 return true;
459 if (atomic_read(&starget->target_blocked) > 0)
460 return true;
461 }
462 return false;
463}
464
465static inline bool scsi_host_is_busy(struct Scsi_Host *shost)
466{
467 if (atomic_read(&shost->host_blocked) > 0)
468 return true;
469 if (shost->host_self_blocked)
470 return true;
471 return false;
472}
473
474static void scsi_starved_list_run(struct Scsi_Host *shost)
475{
476 LIST_HEAD(starved_list);
477 struct scsi_device *sdev;
478 unsigned long flags;
479
480 spin_lock_irqsave(shost->host_lock, flags);
481 list_splice_init(&shost->starved_list, &starved_list);
482
483 while (!list_empty(&starved_list)) {
484 struct request_queue *slq;
485
486 /*
487 * As long as shost is accepting commands and we have
488 * starved queues, call blk_run_queue. scsi_request_fn
489 * drops the queue_lock and can add us back to the
490 * starved_list.
491 *
492 * host_lock protects the starved_list and starved_entry.
493 * scsi_request_fn must get the host_lock before checking
494 * or modifying starved_list or starved_entry.
495 */
496 if (scsi_host_is_busy(shost))
497 break;
498
499 sdev = list_entry(starved_list.next,
500 struct scsi_device, starved_entry);
501 list_del_init(&sdev->starved_entry);
502 if (scsi_target_is_busy(scsi_target(sdev))) {
503 list_move_tail(&sdev->starved_entry,
504 &shost->starved_list);
505 continue;
506 }
507
508 /*
509 * Once we drop the host lock, a racing scsi_remove_device()
510 * call may remove the sdev from the starved list and destroy
511 * it and the queue. Mitigate by taking a reference to the
512 * queue and never touching the sdev again after we drop the
513 * host lock. Note: if __scsi_remove_device() invokes
514 * blk_mq_destroy_queue() before the queue is run from this
515 * function then blk_run_queue() will return immediately since
516 * blk_mq_destroy_queue() marks the queue with QUEUE_FLAG_DYING.
517 */
518 slq = sdev->request_queue;
519 if (!blk_get_queue(slq))
520 continue;
521 spin_unlock_irqrestore(shost->host_lock, flags);
522
523 blk_mq_run_hw_queues(slq, false);
524 blk_put_queue(slq);
525
526 spin_lock_irqsave(shost->host_lock, flags);
527 }
528 /* put any unprocessed entries back */
529 list_splice(&starved_list, &shost->starved_list);
530 spin_unlock_irqrestore(shost->host_lock, flags);
531}
532
533/**
534 * scsi_run_queue - Select a proper request queue to serve next.
535 * @q: last request's queue
536 *
537 * The previous command was completely finished, start a new one if possible.
538 */
539static void scsi_run_queue(struct request_queue *q)
540{
541 struct scsi_device *sdev = q->queuedata;
542
543 if (scsi_target(sdev)->single_lun)
544 scsi_single_lun_run(sdev);
545 if (!list_empty(&sdev->host->starved_list))
546 scsi_starved_list_run(sdev->host);
547
548 /* Note: blk_mq_kick_requeue_list() runs the queue asynchronously. */
549 blk_mq_kick_requeue_list(q);
550}
551
552void scsi_requeue_run_queue(struct work_struct *work)
553{
554 struct scsi_device *sdev;
555 struct request_queue *q;
556
557 sdev = container_of(work, struct scsi_device, requeue_work);
558 q = sdev->request_queue;
559 scsi_run_queue(q);
560}
561
562void scsi_run_host_queues(struct Scsi_Host *shost)
563{
564 struct scsi_device *sdev;
565
566 shost_for_each_device(sdev, shost)
567 scsi_run_queue(sdev->request_queue);
568}
569
570static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
571{
572 if (!blk_rq_is_passthrough(scsi_cmd_to_rq(cmd))) {
573 struct scsi_driver *drv = scsi_cmd_to_driver(cmd);
574
575 if (drv->uninit_command)
576 drv->uninit_command(cmd);
577 }
578}
579
580void scsi_free_sgtables(struct scsi_cmnd *cmd)
581{
582 if (cmd->sdb.table.nents)
583 sg_free_table_chained(&cmd->sdb.table,
584 SCSI_INLINE_SG_CNT);
585 if (scsi_prot_sg_count(cmd))
586 sg_free_table_chained(&cmd->prot_sdb->table,
587 SCSI_INLINE_PROT_SG_CNT);
588}
589EXPORT_SYMBOL_GPL(scsi_free_sgtables);
590
591static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
592{
593 scsi_free_sgtables(cmd);
594 scsi_uninit_cmd(cmd);
595}
596
597static void scsi_run_queue_async(struct scsi_device *sdev)
598{
599 if (scsi_host_in_recovery(sdev->host))
600 return;
601
602 if (scsi_target(sdev)->single_lun ||
603 !list_empty(&sdev->host->starved_list)) {
604 kblockd_schedule_work(&sdev->requeue_work);
605 } else {
606 /*
607 * smp_mb() present in sbitmap_queue_clear() or implied in
608 * .end_io is for ordering writing .device_busy in
609 * scsi_device_unbusy() and reading sdev->restarts.
610 */
611 int old = atomic_read(&sdev->restarts);
612
613 /*
614 * ->restarts has to be kept as non-zero if new budget
615 * contention occurs.
616 *
617 * No need to run queue when either another re-run
618 * queue wins in updating ->restarts or a new budget
619 * contention occurs.
620 */
621 if (old && atomic_cmpxchg(&sdev->restarts, old, 0) == old)
622 blk_mq_run_hw_queues(sdev->request_queue, true);
623 }
624}
625
626/* Returns false when no more bytes to process, true if there are more */
627static bool scsi_end_request(struct request *req, blk_status_t error,
628 unsigned int bytes)
629{
630 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
631 struct scsi_device *sdev = cmd->device;
632 struct request_queue *q = sdev->request_queue;
633
634 if (blk_update_request(req, error, bytes))
635 return true;
636
637 if (q->limits.features & BLK_FEAT_ADD_RANDOM)
638 add_disk_randomness(req->q->disk);
639
640 WARN_ON_ONCE(!blk_rq_is_passthrough(req) &&
641 !(cmd->flags & SCMD_INITIALIZED));
642 cmd->flags = 0;
643
644 /*
645 * Calling rcu_barrier() is not necessary here because the
646 * SCSI error handler guarantees that the function called by
647 * call_rcu() has been called before scsi_end_request() is
648 * called.
649 */
650 destroy_rcu_head(&cmd->rcu);
651
652 /*
653 * In the MQ case the command gets freed by __blk_mq_end_request,
654 * so we have to do all cleanup that depends on it earlier.
655 *
656 * We also can't kick the queues from irq context, so we
657 * will have to defer it to a workqueue.
658 */
659 scsi_mq_uninit_cmd(cmd);
660
661 /*
662 * queue is still alive, so grab the ref for preventing it
663 * from being cleaned up during running queue.
664 */
665 percpu_ref_get(&q->q_usage_counter);
666
667 __blk_mq_end_request(req, error);
668
669 scsi_run_queue_async(sdev);
670
671 percpu_ref_put(&q->q_usage_counter);
672 return false;
673}
674
675/**
676 * scsi_result_to_blk_status - translate a SCSI result code into blk_status_t
677 * @result: scsi error code
678 *
679 * Translate a SCSI result code into a blk_status_t value.
680 */
681static blk_status_t scsi_result_to_blk_status(int result)
682{
683 /*
684 * Check the scsi-ml byte first in case we converted a host or status
685 * byte.
686 */
687 switch (scsi_ml_byte(result)) {
688 case SCSIML_STAT_OK:
689 break;
690 case SCSIML_STAT_RESV_CONFLICT:
691 return BLK_STS_RESV_CONFLICT;
692 case SCSIML_STAT_NOSPC:
693 return BLK_STS_NOSPC;
694 case SCSIML_STAT_MED_ERROR:
695 return BLK_STS_MEDIUM;
696 case SCSIML_STAT_TGT_FAILURE:
697 return BLK_STS_TARGET;
698 case SCSIML_STAT_DL_TIMEOUT:
699 return BLK_STS_DURATION_LIMIT;
700 }
701
702 switch (host_byte(result)) {
703 case DID_OK:
704 if (scsi_status_is_good(result))
705 return BLK_STS_OK;
706 return BLK_STS_IOERR;
707 case DID_TRANSPORT_FAILFAST:
708 case DID_TRANSPORT_MARGINAL:
709 return BLK_STS_TRANSPORT;
710 default:
711 return BLK_STS_IOERR;
712 }
713}
714
715/**
716 * scsi_rq_err_bytes - determine number of bytes till the next failure boundary
717 * @rq: request to examine
718 *
719 * Description:
720 * A request could be merge of IOs which require different failure
721 * handling. This function determines the number of bytes which
722 * can be failed from the beginning of the request without
723 * crossing into area which need to be retried further.
724 *
725 * Return:
726 * The number of bytes to fail.
727 */
728static unsigned int scsi_rq_err_bytes(const struct request *rq)
729{
730 blk_opf_t ff = rq->cmd_flags & REQ_FAILFAST_MASK;
731 unsigned int bytes = 0;
732 struct bio *bio;
733
734 if (!(rq->rq_flags & RQF_MIXED_MERGE))
735 return blk_rq_bytes(rq);
736
737 /*
738 * Currently the only 'mixing' which can happen is between
739 * different fastfail types. We can safely fail portions
740 * which have all the failfast bits that the first one has -
741 * the ones which are at least as eager to fail as the first
742 * one.
743 */
744 for (bio = rq->bio; bio; bio = bio->bi_next) {
745 if ((bio->bi_opf & ff) != ff)
746 break;
747 bytes += bio->bi_iter.bi_size;
748 }
749
750 /* this could lead to infinite loop */
751 BUG_ON(blk_rq_bytes(rq) && !bytes);
752 return bytes;
753}
754
755static bool scsi_cmd_runtime_exceeced(struct scsi_cmnd *cmd)
756{
757 struct request *req = scsi_cmd_to_rq(cmd);
758 unsigned long wait_for;
759
760 if (cmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT)
761 return false;
762
763 wait_for = (cmd->allowed + 1) * req->timeout;
764 if (time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
765 scmd_printk(KERN_ERR, cmd, "timing out command, waited %lus\n",
766 wait_for/HZ);
767 return true;
768 }
769 return false;
770}
771
772/*
773 * When ALUA transition state is returned, reprep the cmd to
774 * use the ALUA handler's transition timeout. Delay the reprep
775 * 1 sec to avoid aggressive retries of the target in that
776 * state.
777 */
778#define ALUA_TRANSITION_REPREP_DELAY 1000
779
780/* Helper for scsi_io_completion() when special action required. */
781static void scsi_io_completion_action(struct scsi_cmnd *cmd, int result)
782{
783 struct request *req = scsi_cmd_to_rq(cmd);
784 int level = 0;
785 enum {ACTION_FAIL, ACTION_REPREP, ACTION_DELAYED_REPREP,
786 ACTION_RETRY, ACTION_DELAYED_RETRY} action;
787 struct scsi_sense_hdr sshdr;
788 bool sense_valid;
789 bool sense_current = true; /* false implies "deferred sense" */
790 blk_status_t blk_stat;
791
792 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
793 if (sense_valid)
794 sense_current = !scsi_sense_is_deferred(&sshdr);
795
796 blk_stat = scsi_result_to_blk_status(result);
797
798 if (host_byte(result) == DID_RESET) {
799 /* Third party bus reset or reset for error recovery
800 * reasons. Just retry the command and see what
801 * happens.
802 */
803 action = ACTION_RETRY;
804 } else if (sense_valid && sense_current) {
805 switch (sshdr.sense_key) {
806 case UNIT_ATTENTION:
807 if (cmd->device->removable) {
808 /* Detected disc change. Set a bit
809 * and quietly refuse further access.
810 */
811 cmd->device->changed = 1;
812 action = ACTION_FAIL;
813 } else {
814 /* Must have been a power glitch, or a
815 * bus reset. Could not have been a
816 * media change, so we just retry the
817 * command and see what happens.
818 */
819 action = ACTION_RETRY;
820 }
821 break;
822 case ILLEGAL_REQUEST:
823 /* If we had an ILLEGAL REQUEST returned, then
824 * we may have performed an unsupported
825 * command. The only thing this should be
826 * would be a ten byte read where only a six
827 * byte read was supported. Also, on a system
828 * where READ CAPACITY failed, we may have
829 * read past the end of the disk.
830 */
831 if ((cmd->device->use_10_for_rw &&
832 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
833 (cmd->cmnd[0] == READ_10 ||
834 cmd->cmnd[0] == WRITE_10)) {
835 /* This will issue a new 6-byte command. */
836 cmd->device->use_10_for_rw = 0;
837 action = ACTION_REPREP;
838 } else if (sshdr.asc == 0x10) /* DIX */ {
839 action = ACTION_FAIL;
840 blk_stat = BLK_STS_PROTECTION;
841 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
842 } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
843 action = ACTION_FAIL;
844 blk_stat = BLK_STS_TARGET;
845 } else
846 action = ACTION_FAIL;
847 break;
848 case ABORTED_COMMAND:
849 action = ACTION_FAIL;
850 if (sshdr.asc == 0x10) /* DIF */
851 blk_stat = BLK_STS_PROTECTION;
852 break;
853 case NOT_READY:
854 /* If the device is in the process of becoming
855 * ready, or has a temporary blockage, retry.
856 */
857 if (sshdr.asc == 0x04) {
858 switch (sshdr.ascq) {
859 case 0x01: /* becoming ready */
860 case 0x04: /* format in progress */
861 case 0x05: /* rebuild in progress */
862 case 0x06: /* recalculation in progress */
863 case 0x07: /* operation in progress */
864 case 0x08: /* Long write in progress */
865 case 0x09: /* self test in progress */
866 case 0x11: /* notify (enable spinup) required */
867 case 0x14: /* space allocation in progress */
868 case 0x1a: /* start stop unit in progress */
869 case 0x1b: /* sanitize in progress */
870 case 0x1d: /* configuration in progress */
871 action = ACTION_DELAYED_RETRY;
872 break;
873 case 0x0a: /* ALUA state transition */
874 action = ACTION_DELAYED_REPREP;
875 break;
876 /*
877 * Depopulation might take many hours,
878 * thus it is not worthwhile to retry.
879 */
880 case 0x24: /* depopulation in progress */
881 case 0x25: /* depopulation restore in progress */
882 fallthrough;
883 default:
884 action = ACTION_FAIL;
885 break;
886 }
887 } else
888 action = ACTION_FAIL;
889 break;
890 case VOLUME_OVERFLOW:
891 /* See SSC3rXX or current. */
892 action = ACTION_FAIL;
893 break;
894 case DATA_PROTECT:
895 action = ACTION_FAIL;
896 if ((sshdr.asc == 0x0C && sshdr.ascq == 0x12) ||
897 (sshdr.asc == 0x55 &&
898 (sshdr.ascq == 0x0E || sshdr.ascq == 0x0F))) {
899 /* Insufficient zone resources */
900 blk_stat = BLK_STS_ZONE_OPEN_RESOURCE;
901 }
902 break;
903 case COMPLETED:
904 fallthrough;
905 default:
906 action = ACTION_FAIL;
907 break;
908 }
909 } else
910 action = ACTION_FAIL;
911
912 if (action != ACTION_FAIL && scsi_cmd_runtime_exceeced(cmd))
913 action = ACTION_FAIL;
914
915 switch (action) {
916 case ACTION_FAIL:
917 /* Give up and fail the remainder of the request */
918 if (!(req->rq_flags & RQF_QUIET)) {
919 static DEFINE_RATELIMIT_STATE(_rs,
920 DEFAULT_RATELIMIT_INTERVAL,
921 DEFAULT_RATELIMIT_BURST);
922
923 if (unlikely(scsi_logging_level))
924 level =
925 SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
926 SCSI_LOG_MLCOMPLETE_BITS);
927
928 /*
929 * if logging is enabled the failure will be printed
930 * in scsi_log_completion(), so avoid duplicate messages
931 */
932 if (!level && __ratelimit(&_rs)) {
933 scsi_print_result(cmd, NULL, FAILED);
934 if (sense_valid)
935 scsi_print_sense(cmd);
936 scsi_print_command(cmd);
937 }
938 }
939 if (!scsi_end_request(req, blk_stat, scsi_rq_err_bytes(req)))
940 return;
941 fallthrough;
942 case ACTION_REPREP:
943 scsi_mq_requeue_cmd(cmd, 0);
944 break;
945 case ACTION_DELAYED_REPREP:
946 scsi_mq_requeue_cmd(cmd, ALUA_TRANSITION_REPREP_DELAY);
947 break;
948 case ACTION_RETRY:
949 /* Retry the same command immediately */
950 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, false);
951 break;
952 case ACTION_DELAYED_RETRY:
953 /* Retry the same command after a delay */
954 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, false);
955 break;
956 }
957}
958
959/*
960 * Helper for scsi_io_completion() when cmd->result is non-zero. Returns a
961 * new result that may suppress further error checking. Also modifies
962 * *blk_statp in some cases.
963 */
964static int scsi_io_completion_nz_result(struct scsi_cmnd *cmd, int result,
965 blk_status_t *blk_statp)
966{
967 bool sense_valid;
968 bool sense_current = true; /* false implies "deferred sense" */
969 struct request *req = scsi_cmd_to_rq(cmd);
970 struct scsi_sense_hdr sshdr;
971
972 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
973 if (sense_valid)
974 sense_current = !scsi_sense_is_deferred(&sshdr);
975
976 if (blk_rq_is_passthrough(req)) {
977 if (sense_valid) {
978 /*
979 * SG_IO wants current and deferred errors
980 */
981 cmd->sense_len = min(8 + cmd->sense_buffer[7],
982 SCSI_SENSE_BUFFERSIZE);
983 }
984 if (sense_current)
985 *blk_statp = scsi_result_to_blk_status(result);
986 } else if (blk_rq_bytes(req) == 0 && sense_current) {
987 /*
988 * Flush commands do not transfers any data, and thus cannot use
989 * good_bytes != blk_rq_bytes(req) as the signal for an error.
990 * This sets *blk_statp explicitly for the problem case.
991 */
992 *blk_statp = scsi_result_to_blk_status(result);
993 }
994 /*
995 * Recovered errors need reporting, but they're always treated as
996 * success, so fiddle the result code here. For passthrough requests
997 * we already took a copy of the original into sreq->result which
998 * is what gets returned to the user
999 */
1000 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
1001 bool do_print = true;
1002 /*
1003 * if ATA PASS-THROUGH INFORMATION AVAILABLE [0x0, 0x1d]
1004 * skip print since caller wants ATA registers. Only occurs
1005 * on SCSI ATA PASS_THROUGH commands when CK_COND=1
1006 */
1007 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
1008 do_print = false;
1009 else if (req->rq_flags & RQF_QUIET)
1010 do_print = false;
1011 if (do_print)
1012 scsi_print_sense(cmd);
1013 result = 0;
1014 /* for passthrough, *blk_statp may be set */
1015 *blk_statp = BLK_STS_OK;
1016 }
1017 /*
1018 * Another corner case: the SCSI status byte is non-zero but 'good'.
1019 * Example: PRE-FETCH command returns SAM_STAT_CONDITION_MET when
1020 * it is able to fit nominated LBs in its cache (and SAM_STAT_GOOD
1021 * if it can't fit). Treat SAM_STAT_CONDITION_MET and the related
1022 * intermediate statuses (both obsolete in SAM-4) as good.
1023 */
1024 if ((result & 0xff) && scsi_status_is_good(result)) {
1025 result = 0;
1026 *blk_statp = BLK_STS_OK;
1027 }
1028 return result;
1029}
1030
1031/**
1032 * scsi_io_completion - Completion processing for SCSI commands.
1033 * @cmd: command that is finished.
1034 * @good_bytes: number of processed bytes.
1035 *
1036 * We will finish off the specified number of sectors. If we are done, the
1037 * command block will be released and the queue function will be goosed. If we
1038 * are not done then we have to figure out what to do next:
1039 *
1040 * a) We can call scsi_mq_requeue_cmd(). The request will be
1041 * unprepared and put back on the queue. Then a new command will
1042 * be created for it. This should be used if we made forward
1043 * progress, or if we want to switch from READ(10) to READ(6) for
1044 * example.
1045 *
1046 * b) We can call scsi_io_completion_action(). The request will be
1047 * put back on the queue and retried using the same command as
1048 * before, possibly after a delay.
1049 *
1050 * c) We can call scsi_end_request() with blk_stat other than
1051 * BLK_STS_OK, to fail the remainder of the request.
1052 */
1053void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
1054{
1055 int result = cmd->result;
1056 struct request *req = scsi_cmd_to_rq(cmd);
1057 blk_status_t blk_stat = BLK_STS_OK;
1058
1059 if (unlikely(result)) /* a nz result may or may not be an error */
1060 result = scsi_io_completion_nz_result(cmd, result, &blk_stat);
1061
1062 /*
1063 * Next deal with any sectors which we were able to correctly
1064 * handle.
1065 */
1066 SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd,
1067 "%u sectors total, %d bytes done.\n",
1068 blk_rq_sectors(req), good_bytes));
1069
1070 /*
1071 * Failed, zero length commands always need to drop down
1072 * to retry code. Fast path should return in this block.
1073 */
1074 if (likely(blk_rq_bytes(req) > 0 || blk_stat == BLK_STS_OK)) {
1075 if (likely(!scsi_end_request(req, blk_stat, good_bytes)))
1076 return; /* no bytes remaining */
1077 }
1078
1079 /* Kill remainder if no retries. */
1080 if (unlikely(blk_stat && scsi_noretry_cmd(cmd))) {
1081 if (scsi_end_request(req, blk_stat, blk_rq_bytes(req)))
1082 WARN_ONCE(true,
1083 "Bytes remaining after failed, no-retry command");
1084 return;
1085 }
1086
1087 /*
1088 * If there had been no error, but we have leftover bytes in the
1089 * request just queue the command up again.
1090 */
1091 if (likely(result == 0))
1092 scsi_mq_requeue_cmd(cmd, 0);
1093 else
1094 scsi_io_completion_action(cmd, result);
1095}
1096
1097static inline bool scsi_cmd_needs_dma_drain(struct scsi_device *sdev,
1098 struct request *rq)
1099{
1100 return sdev->dma_drain_len && blk_rq_is_passthrough(rq) &&
1101 !op_is_write(req_op(rq)) &&
1102 sdev->host->hostt->dma_need_drain(rq);
1103}
1104
1105/**
1106 * scsi_alloc_sgtables - Allocate and initialize data and integrity scatterlists
1107 * @cmd: SCSI command data structure to initialize.
1108 *
1109 * Initializes @cmd->sdb and also @cmd->prot_sdb if data integrity is enabled
1110 * for @cmd.
1111 *
1112 * Returns:
1113 * * BLK_STS_OK - on success
1114 * * BLK_STS_RESOURCE - if the failure is retryable
1115 * * BLK_STS_IOERR - if the failure is fatal
1116 */
1117blk_status_t scsi_alloc_sgtables(struct scsi_cmnd *cmd)
1118{
1119 struct scsi_device *sdev = cmd->device;
1120 struct request *rq = scsi_cmd_to_rq(cmd);
1121 unsigned short nr_segs = blk_rq_nr_phys_segments(rq);
1122 struct scatterlist *last_sg = NULL;
1123 blk_status_t ret;
1124 bool need_drain = scsi_cmd_needs_dma_drain(sdev, rq);
1125 int count;
1126
1127 if (WARN_ON_ONCE(!nr_segs))
1128 return BLK_STS_IOERR;
1129
1130 /*
1131 * Make sure there is space for the drain. The driver must adjust
1132 * max_hw_segments to be prepared for this.
1133 */
1134 if (need_drain)
1135 nr_segs++;
1136
1137 /*
1138 * If sg table allocation fails, requeue request later.
1139 */
1140 if (unlikely(sg_alloc_table_chained(&cmd->sdb.table, nr_segs,
1141 cmd->sdb.table.sgl, SCSI_INLINE_SG_CNT)))
1142 return BLK_STS_RESOURCE;
1143
1144 /*
1145 * Next, walk the list, and fill in the addresses and sizes of
1146 * each segment.
1147 */
1148 count = __blk_rq_map_sg(rq->q, rq, cmd->sdb.table.sgl, &last_sg);
1149
1150 if (blk_rq_bytes(rq) & rq->q->limits.dma_pad_mask) {
1151 unsigned int pad_len =
1152 (rq->q->limits.dma_pad_mask & ~blk_rq_bytes(rq)) + 1;
1153
1154 last_sg->length += pad_len;
1155 cmd->extra_len += pad_len;
1156 }
1157
1158 if (need_drain) {
1159 sg_unmark_end(last_sg);
1160 last_sg = sg_next(last_sg);
1161 sg_set_buf(last_sg, sdev->dma_drain_buf, sdev->dma_drain_len);
1162 sg_mark_end(last_sg);
1163
1164 cmd->extra_len += sdev->dma_drain_len;
1165 count++;
1166 }
1167
1168 BUG_ON(count > cmd->sdb.table.nents);
1169 cmd->sdb.table.nents = count;
1170 cmd->sdb.length = blk_rq_payload_bytes(rq);
1171
1172 if (blk_integrity_rq(rq)) {
1173 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1174
1175 if (WARN_ON_ONCE(!prot_sdb)) {
1176 /*
1177 * This can happen if someone (e.g. multipath)
1178 * queues a command to a device on an adapter
1179 * that does not support DIX.
1180 */
1181 ret = BLK_STS_IOERR;
1182 goto out_free_sgtables;
1183 }
1184
1185 if (sg_alloc_table_chained(&prot_sdb->table,
1186 rq->nr_integrity_segments,
1187 prot_sdb->table.sgl,
1188 SCSI_INLINE_PROT_SG_CNT)) {
1189 ret = BLK_STS_RESOURCE;
1190 goto out_free_sgtables;
1191 }
1192
1193 count = blk_rq_map_integrity_sg(rq, prot_sdb->table.sgl);
1194 cmd->prot_sdb = prot_sdb;
1195 cmd->prot_sdb->table.nents = count;
1196 }
1197
1198 return BLK_STS_OK;
1199out_free_sgtables:
1200 scsi_free_sgtables(cmd);
1201 return ret;
1202}
1203EXPORT_SYMBOL(scsi_alloc_sgtables);
1204
1205/**
1206 * scsi_initialize_rq - initialize struct scsi_cmnd partially
1207 * @rq: Request associated with the SCSI command to be initialized.
1208 *
1209 * This function initializes the members of struct scsi_cmnd that must be
1210 * initialized before request processing starts and that won't be
1211 * reinitialized if a SCSI command is requeued.
1212 */
1213static void scsi_initialize_rq(struct request *rq)
1214{
1215 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1216
1217 memset(cmd->cmnd, 0, sizeof(cmd->cmnd));
1218 cmd->cmd_len = MAX_COMMAND_SIZE;
1219 cmd->sense_len = 0;
1220 init_rcu_head(&cmd->rcu);
1221 cmd->jiffies_at_alloc = jiffies;
1222 cmd->retries = 0;
1223}
1224
1225struct request *scsi_alloc_request(struct request_queue *q, blk_opf_t opf,
1226 blk_mq_req_flags_t flags)
1227{
1228 struct request *rq;
1229
1230 rq = blk_mq_alloc_request(q, opf, flags);
1231 if (!IS_ERR(rq))
1232 scsi_initialize_rq(rq);
1233 return rq;
1234}
1235EXPORT_SYMBOL_GPL(scsi_alloc_request);
1236
1237/*
1238 * Only called when the request isn't completed by SCSI, and not freed by
1239 * SCSI
1240 */
1241static void scsi_cleanup_rq(struct request *rq)
1242{
1243 if (rq->rq_flags & RQF_DONTPREP) {
1244 scsi_mq_uninit_cmd(blk_mq_rq_to_pdu(rq));
1245 rq->rq_flags &= ~RQF_DONTPREP;
1246 }
1247}
1248
1249/* Called before a request is prepared. See also scsi_mq_prep_fn(). */
1250void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd)
1251{
1252 struct request *rq = scsi_cmd_to_rq(cmd);
1253
1254 if (!blk_rq_is_passthrough(rq) && !(cmd->flags & SCMD_INITIALIZED)) {
1255 cmd->flags |= SCMD_INITIALIZED;
1256 scsi_initialize_rq(rq);
1257 }
1258
1259 cmd->device = dev;
1260 INIT_LIST_HEAD(&cmd->eh_entry);
1261 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
1262}
1263
1264static blk_status_t scsi_setup_scsi_cmnd(struct scsi_device *sdev,
1265 struct request *req)
1266{
1267 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1268
1269 /*
1270 * Passthrough requests may transfer data, in which case they must
1271 * a bio attached to them. Or they might contain a SCSI command
1272 * that does not transfer data, in which case they may optionally
1273 * submit a request without an attached bio.
1274 */
1275 if (req->bio) {
1276 blk_status_t ret = scsi_alloc_sgtables(cmd);
1277 if (unlikely(ret != BLK_STS_OK))
1278 return ret;
1279 } else {
1280 BUG_ON(blk_rq_bytes(req));
1281
1282 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1283 }
1284
1285 cmd->transfersize = blk_rq_bytes(req);
1286 return BLK_STS_OK;
1287}
1288
1289static blk_status_t
1290scsi_device_state_check(struct scsi_device *sdev, struct request *req)
1291{
1292 switch (sdev->sdev_state) {
1293 case SDEV_CREATED:
1294 return BLK_STS_OK;
1295 case SDEV_OFFLINE:
1296 case SDEV_TRANSPORT_OFFLINE:
1297 /*
1298 * If the device is offline we refuse to process any
1299 * commands. The device must be brought online
1300 * before trying any recovery commands.
1301 */
1302 if (!sdev->offline_already) {
1303 sdev->offline_already = true;
1304 sdev_printk(KERN_ERR, sdev,
1305 "rejecting I/O to offline device\n");
1306 }
1307 return BLK_STS_IOERR;
1308 case SDEV_DEL:
1309 /*
1310 * If the device is fully deleted, we refuse to
1311 * process any commands as well.
1312 */
1313 sdev_printk(KERN_ERR, sdev,
1314 "rejecting I/O to dead device\n");
1315 return BLK_STS_IOERR;
1316 case SDEV_BLOCK:
1317 case SDEV_CREATED_BLOCK:
1318 return BLK_STS_RESOURCE;
1319 case SDEV_QUIESCE:
1320 /*
1321 * If the device is blocked we only accept power management
1322 * commands.
1323 */
1324 if (req && WARN_ON_ONCE(!(req->rq_flags & RQF_PM)))
1325 return BLK_STS_RESOURCE;
1326 return BLK_STS_OK;
1327 default:
1328 /*
1329 * For any other not fully online state we only allow
1330 * power management commands.
1331 */
1332 if (req && !(req->rq_flags & RQF_PM))
1333 return BLK_STS_OFFLINE;
1334 return BLK_STS_OK;
1335 }
1336}
1337
1338/*
1339 * scsi_dev_queue_ready: if we can send requests to sdev, assign one token
1340 * and return the token else return -1.
1341 */
1342static inline int scsi_dev_queue_ready(struct request_queue *q,
1343 struct scsi_device *sdev)
1344{
1345 int token;
1346
1347 token = sbitmap_get(&sdev->budget_map);
1348 if (token < 0)
1349 return -1;
1350
1351 if (!atomic_read(&sdev->device_blocked))
1352 return token;
1353
1354 /*
1355 * Only unblock if no other commands are pending and
1356 * if device_blocked has decreased to zero
1357 */
1358 if (scsi_device_busy(sdev) > 1 ||
1359 atomic_dec_return(&sdev->device_blocked) > 0) {
1360 sbitmap_put(&sdev->budget_map, token);
1361 return -1;
1362 }
1363
1364 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev,
1365 "unblocking device at zero depth\n"));
1366
1367 return token;
1368}
1369
1370/*
1371 * scsi_target_queue_ready: checks if there we can send commands to target
1372 * @sdev: scsi device on starget to check.
1373 */
1374static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1375 struct scsi_device *sdev)
1376{
1377 struct scsi_target *starget = scsi_target(sdev);
1378 unsigned int busy;
1379
1380 if (starget->single_lun) {
1381 spin_lock_irq(shost->host_lock);
1382 if (starget->starget_sdev_user &&
1383 starget->starget_sdev_user != sdev) {
1384 spin_unlock_irq(shost->host_lock);
1385 return 0;
1386 }
1387 starget->starget_sdev_user = sdev;
1388 spin_unlock_irq(shost->host_lock);
1389 }
1390
1391 if (starget->can_queue <= 0)
1392 return 1;
1393
1394 busy = atomic_inc_return(&starget->target_busy) - 1;
1395 if (atomic_read(&starget->target_blocked) > 0) {
1396 if (busy)
1397 goto starved;
1398
1399 /*
1400 * unblock after target_blocked iterates to zero
1401 */
1402 if (atomic_dec_return(&starget->target_blocked) > 0)
1403 goto out_dec;
1404
1405 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1406 "unblocking target at zero depth\n"));
1407 }
1408
1409 if (busy >= starget->can_queue)
1410 goto starved;
1411
1412 return 1;
1413
1414starved:
1415 spin_lock_irq(shost->host_lock);
1416 list_move_tail(&sdev->starved_entry, &shost->starved_list);
1417 spin_unlock_irq(shost->host_lock);
1418out_dec:
1419 if (starget->can_queue > 0)
1420 atomic_dec(&starget->target_busy);
1421 return 0;
1422}
1423
1424/*
1425 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1426 * return 0. We must end up running the queue again whenever 0 is
1427 * returned, else IO can hang.
1428 */
1429static inline int scsi_host_queue_ready(struct request_queue *q,
1430 struct Scsi_Host *shost,
1431 struct scsi_device *sdev,
1432 struct scsi_cmnd *cmd)
1433{
1434 if (atomic_read(&shost->host_blocked) > 0) {
1435 if (scsi_host_busy(shost) > 0)
1436 goto starved;
1437
1438 /*
1439 * unblock after host_blocked iterates to zero
1440 */
1441 if (atomic_dec_return(&shost->host_blocked) > 0)
1442 goto out_dec;
1443
1444 SCSI_LOG_MLQUEUE(3,
1445 shost_printk(KERN_INFO, shost,
1446 "unblocking host at zero depth\n"));
1447 }
1448
1449 if (shost->host_self_blocked)
1450 goto starved;
1451
1452 /* We're OK to process the command, so we can't be starved */
1453 if (!list_empty(&sdev->starved_entry)) {
1454 spin_lock_irq(shost->host_lock);
1455 if (!list_empty(&sdev->starved_entry))
1456 list_del_init(&sdev->starved_entry);
1457 spin_unlock_irq(shost->host_lock);
1458 }
1459
1460 __set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1461
1462 return 1;
1463
1464starved:
1465 spin_lock_irq(shost->host_lock);
1466 if (list_empty(&sdev->starved_entry))
1467 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1468 spin_unlock_irq(shost->host_lock);
1469out_dec:
1470 scsi_dec_host_busy(shost, cmd);
1471 return 0;
1472}
1473
1474/*
1475 * Busy state exporting function for request stacking drivers.
1476 *
1477 * For efficiency, no lock is taken to check the busy state of
1478 * shost/starget/sdev, since the returned value is not guaranteed and
1479 * may be changed after request stacking drivers call the function,
1480 * regardless of taking lock or not.
1481 *
1482 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1483 * needs to return 'not busy'. Otherwise, request stacking drivers
1484 * may hold requests forever.
1485 */
1486static bool scsi_mq_lld_busy(struct request_queue *q)
1487{
1488 struct scsi_device *sdev = q->queuedata;
1489 struct Scsi_Host *shost;
1490
1491 if (blk_queue_dying(q))
1492 return false;
1493
1494 shost = sdev->host;
1495
1496 /*
1497 * Ignore host/starget busy state.
1498 * Since block layer does not have a concept of fairness across
1499 * multiple queues, congestion of host/starget needs to be handled
1500 * in SCSI layer.
1501 */
1502 if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
1503 return true;
1504
1505 return false;
1506}
1507
1508/*
1509 * Block layer request completion callback. May be called from interrupt
1510 * context.
1511 */
1512static void scsi_complete(struct request *rq)
1513{
1514 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1515 enum scsi_disposition disposition;
1516
1517 INIT_LIST_HEAD(&cmd->eh_entry);
1518
1519 atomic_inc(&cmd->device->iodone_cnt);
1520 if (cmd->result)
1521 atomic_inc(&cmd->device->ioerr_cnt);
1522
1523 disposition = scsi_decide_disposition(cmd);
1524 if (disposition != SUCCESS && scsi_cmd_runtime_exceeced(cmd))
1525 disposition = SUCCESS;
1526
1527 scsi_log_completion(cmd, disposition);
1528
1529 switch (disposition) {
1530 case SUCCESS:
1531 scsi_finish_command(cmd);
1532 break;
1533 case NEEDS_RETRY:
1534 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
1535 break;
1536 case ADD_TO_MLQUEUE:
1537 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1538 break;
1539 default:
1540 scsi_eh_scmd_add(cmd);
1541 break;
1542 }
1543}
1544
1545/**
1546 * scsi_dispatch_cmd - Dispatch a command to the low-level driver.
1547 * @cmd: command block we are dispatching.
1548 *
1549 * Return: nonzero return request was rejected and device's queue needs to be
1550 * plugged.
1551 */
1552static int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
1553{
1554 struct Scsi_Host *host = cmd->device->host;
1555 int rtn = 0;
1556
1557 atomic_inc(&cmd->device->iorequest_cnt);
1558
1559 /* check if the device is still usable */
1560 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
1561 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
1562 * returns an immediate error upwards, and signals
1563 * that the device is no longer present */
1564 cmd->result = DID_NO_CONNECT << 16;
1565 goto done;
1566 }
1567
1568 /* Check to see if the scsi lld made this device blocked. */
1569 if (unlikely(scsi_device_blocked(cmd->device))) {
1570 /*
1571 * in blocked state, the command is just put back on
1572 * the device queue. The suspend state has already
1573 * blocked the queue so future requests should not
1574 * occur until the device transitions out of the
1575 * suspend state.
1576 */
1577 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1578 "queuecommand : device blocked\n"));
1579 atomic_dec(&cmd->device->iorequest_cnt);
1580 return SCSI_MLQUEUE_DEVICE_BUSY;
1581 }
1582
1583 /* Store the LUN value in cmnd, if needed. */
1584 if (cmd->device->lun_in_cdb)
1585 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
1586 (cmd->device->lun << 5 & 0xe0);
1587
1588 scsi_log_send(cmd);
1589
1590 /*
1591 * Before we queue this command, check if the command
1592 * length exceeds what the host adapter can handle.
1593 */
1594 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
1595 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1596 "queuecommand : command too long. "
1597 "cdb_size=%d host->max_cmd_len=%d\n",
1598 cmd->cmd_len, cmd->device->host->max_cmd_len));
1599 cmd->result = (DID_ABORT << 16);
1600 goto done;
1601 }
1602
1603 if (unlikely(host->shost_state == SHOST_DEL)) {
1604 cmd->result = (DID_NO_CONNECT << 16);
1605 goto done;
1606
1607 }
1608
1609 trace_scsi_dispatch_cmd_start(cmd);
1610 rtn = host->hostt->queuecommand(host, cmd);
1611 if (rtn) {
1612 atomic_dec(&cmd->device->iorequest_cnt);
1613 trace_scsi_dispatch_cmd_error(cmd, rtn);
1614 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
1615 rtn != SCSI_MLQUEUE_TARGET_BUSY)
1616 rtn = SCSI_MLQUEUE_HOST_BUSY;
1617
1618 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1619 "queuecommand : request rejected\n"));
1620 }
1621
1622 return rtn;
1623 done:
1624 scsi_done(cmd);
1625 return 0;
1626}
1627
1628/* Size in bytes of the sg-list stored in the scsi-mq command-private data. */
1629static unsigned int scsi_mq_inline_sgl_size(struct Scsi_Host *shost)
1630{
1631 return min_t(unsigned int, shost->sg_tablesize, SCSI_INLINE_SG_CNT) *
1632 sizeof(struct scatterlist);
1633}
1634
1635static blk_status_t scsi_prepare_cmd(struct request *req)
1636{
1637 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1638 struct scsi_device *sdev = req->q->queuedata;
1639 struct Scsi_Host *shost = sdev->host;
1640 bool in_flight = test_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1641 struct scatterlist *sg;
1642
1643 scsi_init_command(sdev, cmd);
1644
1645 cmd->eh_eflags = 0;
1646 cmd->prot_type = 0;
1647 cmd->prot_flags = 0;
1648 cmd->submitter = 0;
1649 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1650 cmd->underflow = 0;
1651 cmd->transfersize = 0;
1652 cmd->host_scribble = NULL;
1653 cmd->result = 0;
1654 cmd->extra_len = 0;
1655 cmd->state = 0;
1656 if (in_flight)
1657 __set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1658
1659 cmd->prot_op = SCSI_PROT_NORMAL;
1660 if (blk_rq_bytes(req))
1661 cmd->sc_data_direction = rq_dma_dir(req);
1662 else
1663 cmd->sc_data_direction = DMA_NONE;
1664
1665 sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
1666 cmd->sdb.table.sgl = sg;
1667
1668 if (scsi_host_get_prot(shost)) {
1669 memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer));
1670
1671 cmd->prot_sdb->table.sgl =
1672 (struct scatterlist *)(cmd->prot_sdb + 1);
1673 }
1674
1675 /*
1676 * Special handling for passthrough commands, which don't go to the ULP
1677 * at all:
1678 */
1679 if (blk_rq_is_passthrough(req))
1680 return scsi_setup_scsi_cmnd(sdev, req);
1681
1682 if (sdev->handler && sdev->handler->prep_fn) {
1683 blk_status_t ret = sdev->handler->prep_fn(sdev, req);
1684
1685 if (ret != BLK_STS_OK)
1686 return ret;
1687 }
1688
1689 /* Usually overridden by the ULP */
1690 cmd->allowed = 0;
1691 memset(cmd->cmnd, 0, sizeof(cmd->cmnd));
1692 return scsi_cmd_to_driver(cmd)->init_command(cmd);
1693}
1694
1695static void scsi_done_internal(struct scsi_cmnd *cmd, bool complete_directly)
1696{
1697 struct request *req = scsi_cmd_to_rq(cmd);
1698
1699 switch (cmd->submitter) {
1700 case SUBMITTED_BY_BLOCK_LAYER:
1701 break;
1702 case SUBMITTED_BY_SCSI_ERROR_HANDLER:
1703 return scsi_eh_done(cmd);
1704 case SUBMITTED_BY_SCSI_RESET_IOCTL:
1705 return;
1706 }
1707
1708 if (unlikely(blk_should_fake_timeout(scsi_cmd_to_rq(cmd)->q)))
1709 return;
1710 if (unlikely(test_and_set_bit(SCMD_STATE_COMPLETE, &cmd->state)))
1711 return;
1712 trace_scsi_dispatch_cmd_done(cmd);
1713
1714 if (complete_directly)
1715 blk_mq_complete_request_direct(req, scsi_complete);
1716 else
1717 blk_mq_complete_request(req);
1718}
1719
1720void scsi_done(struct scsi_cmnd *cmd)
1721{
1722 scsi_done_internal(cmd, false);
1723}
1724EXPORT_SYMBOL(scsi_done);
1725
1726void scsi_done_direct(struct scsi_cmnd *cmd)
1727{
1728 scsi_done_internal(cmd, true);
1729}
1730EXPORT_SYMBOL(scsi_done_direct);
1731
1732static void scsi_mq_put_budget(struct request_queue *q, int budget_token)
1733{
1734 struct scsi_device *sdev = q->queuedata;
1735
1736 sbitmap_put(&sdev->budget_map, budget_token);
1737}
1738
1739/*
1740 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
1741 * not change behaviour from the previous unplug mechanism, experimentation
1742 * may prove this needs changing.
1743 */
1744#define SCSI_QUEUE_DELAY 3
1745
1746static int scsi_mq_get_budget(struct request_queue *q)
1747{
1748 struct scsi_device *sdev = q->queuedata;
1749 int token = scsi_dev_queue_ready(q, sdev);
1750
1751 if (token >= 0)
1752 return token;
1753
1754 atomic_inc(&sdev->restarts);
1755
1756 /*
1757 * Orders atomic_inc(&sdev->restarts) and atomic_read(&sdev->device_busy).
1758 * .restarts must be incremented before .device_busy is read because the
1759 * code in scsi_run_queue_async() depends on the order of these operations.
1760 */
1761 smp_mb__after_atomic();
1762
1763 /*
1764 * If all in-flight requests originated from this LUN are completed
1765 * before reading .device_busy, sdev->device_busy will be observed as
1766 * zero, then blk_mq_delay_run_hw_queues() will dispatch this request
1767 * soon. Otherwise, completion of one of these requests will observe
1768 * the .restarts flag, and the request queue will be run for handling
1769 * this request, see scsi_end_request().
1770 */
1771 if (unlikely(scsi_device_busy(sdev) == 0 &&
1772 !scsi_device_blocked(sdev)))
1773 blk_mq_delay_run_hw_queues(sdev->request_queue, SCSI_QUEUE_DELAY);
1774 return -1;
1775}
1776
1777static void scsi_mq_set_rq_budget_token(struct request *req, int token)
1778{
1779 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1780
1781 cmd->budget_token = token;
1782}
1783
1784static int scsi_mq_get_rq_budget_token(struct request *req)
1785{
1786 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1787
1788 return cmd->budget_token;
1789}
1790
1791static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
1792 const struct blk_mq_queue_data *bd)
1793{
1794 struct request *req = bd->rq;
1795 struct request_queue *q = req->q;
1796 struct scsi_device *sdev = q->queuedata;
1797 struct Scsi_Host *shost = sdev->host;
1798 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1799 blk_status_t ret;
1800 int reason;
1801
1802 WARN_ON_ONCE(cmd->budget_token < 0);
1803
1804 /*
1805 * If the device is not in running state we will reject some or all
1806 * commands.
1807 */
1808 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
1809 ret = scsi_device_state_check(sdev, req);
1810 if (ret != BLK_STS_OK)
1811 goto out_put_budget;
1812 }
1813
1814 ret = BLK_STS_RESOURCE;
1815 if (!scsi_target_queue_ready(shost, sdev))
1816 goto out_put_budget;
1817 if (unlikely(scsi_host_in_recovery(shost))) {
1818 if (cmd->flags & SCMD_FAIL_IF_RECOVERING)
1819 ret = BLK_STS_OFFLINE;
1820 goto out_dec_target_busy;
1821 }
1822 if (!scsi_host_queue_ready(q, shost, sdev, cmd))
1823 goto out_dec_target_busy;
1824
1825 /*
1826 * Only clear the driver-private command data if the LLD does not supply
1827 * a function to initialize that data.
1828 */
1829 if (shost->hostt->cmd_size && !shost->hostt->init_cmd_priv)
1830 memset(cmd + 1, 0, shost->hostt->cmd_size);
1831
1832 if (!(req->rq_flags & RQF_DONTPREP)) {
1833 ret = scsi_prepare_cmd(req);
1834 if (ret != BLK_STS_OK)
1835 goto out_dec_host_busy;
1836 req->rq_flags |= RQF_DONTPREP;
1837 } else {
1838 clear_bit(SCMD_STATE_COMPLETE, &cmd->state);
1839 }
1840
1841 cmd->flags &= SCMD_PRESERVED_FLAGS;
1842 if (sdev->simple_tags)
1843 cmd->flags |= SCMD_TAGGED;
1844 if (bd->last)
1845 cmd->flags |= SCMD_LAST;
1846
1847 scsi_set_resid(cmd, 0);
1848 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
1849 cmd->submitter = SUBMITTED_BY_BLOCK_LAYER;
1850
1851 blk_mq_start_request(req);
1852 reason = scsi_dispatch_cmd(cmd);
1853 if (reason) {
1854 scsi_set_blocked(cmd, reason);
1855 ret = BLK_STS_RESOURCE;
1856 goto out_dec_host_busy;
1857 }
1858
1859 return BLK_STS_OK;
1860
1861out_dec_host_busy:
1862 scsi_dec_host_busy(shost, cmd);
1863out_dec_target_busy:
1864 if (scsi_target(sdev)->can_queue > 0)
1865 atomic_dec(&scsi_target(sdev)->target_busy);
1866out_put_budget:
1867 scsi_mq_put_budget(q, cmd->budget_token);
1868 cmd->budget_token = -1;
1869 switch (ret) {
1870 case BLK_STS_OK:
1871 break;
1872 case BLK_STS_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_limits(struct Scsi_Host *shost, struct queue_limits *lim)
1968{
1969 struct device *dev = shost->dma_dev;
1970
1971 memset(lim, 0, sizeof(*lim));
1972 lim->max_segments =
1973 min_t(unsigned short, shost->sg_tablesize, SG_MAX_SEGMENTS);
1974
1975 if (scsi_host_prot_dma(shost)) {
1976 shost->sg_prot_tablesize =
1977 min_not_zero(shost->sg_prot_tablesize,
1978 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
1979 BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
1980 lim->max_integrity_segments = shost->sg_prot_tablesize;
1981 }
1982
1983 lim->max_hw_sectors = shost->max_sectors;
1984 lim->seg_boundary_mask = shost->dma_boundary;
1985 lim->max_segment_size = shost->max_segment_size;
1986 lim->virt_boundary_mask = shost->virt_boundary_mask;
1987 lim->dma_alignment = max_t(unsigned int,
1988 shost->dma_alignment, dma_get_cache_alignment() - 1);
1989
1990 if (shost->no_highmem)
1991 lim->features |= BLK_FEAT_BOUNCE_HIGH;
1992
1993 /*
1994 * Propagate the DMA formation properties to the dma-mapping layer as
1995 * a courtesy service to the LLDDs. This needs to check that the buses
1996 * actually support the DMA API first, though.
1997 */
1998 if (dev->dma_parms) {
1999 dma_set_seg_boundary(dev, shost->dma_boundary);
2000 dma_set_max_seg_size(dev, shost->max_segment_size);
2001 }
2002}
2003EXPORT_SYMBOL_GPL(scsi_init_limits);
2004
2005static const struct blk_mq_ops scsi_mq_ops_no_commit = {
2006 .get_budget = scsi_mq_get_budget,
2007 .put_budget = scsi_mq_put_budget,
2008 .queue_rq = scsi_queue_rq,
2009 .complete = scsi_complete,
2010 .timeout = scsi_timeout,
2011#ifdef CONFIG_BLK_DEBUG_FS
2012 .show_rq = scsi_show_rq,
2013#endif
2014 .init_request = scsi_mq_init_request,
2015 .exit_request = scsi_mq_exit_request,
2016 .cleanup_rq = scsi_cleanup_rq,
2017 .busy = scsi_mq_lld_busy,
2018 .map_queues = scsi_map_queues,
2019 .init_hctx = scsi_init_hctx,
2020 .poll = scsi_mq_poll,
2021 .set_rq_budget_token = scsi_mq_set_rq_budget_token,
2022 .get_rq_budget_token = scsi_mq_get_rq_budget_token,
2023};
2024
2025
2026static void scsi_commit_rqs(struct blk_mq_hw_ctx *hctx)
2027{
2028 struct Scsi_Host *shost = hctx->driver_data;
2029
2030 shost->hostt->commit_rqs(shost, hctx->queue_num);
2031}
2032
2033static const struct blk_mq_ops scsi_mq_ops = {
2034 .get_budget = scsi_mq_get_budget,
2035 .put_budget = scsi_mq_put_budget,
2036 .queue_rq = scsi_queue_rq,
2037 .commit_rqs = scsi_commit_rqs,
2038 .complete = scsi_complete,
2039 .timeout = scsi_timeout,
2040#ifdef CONFIG_BLK_DEBUG_FS
2041 .show_rq = scsi_show_rq,
2042#endif
2043 .init_request = scsi_mq_init_request,
2044 .exit_request = scsi_mq_exit_request,
2045 .cleanup_rq = scsi_cleanup_rq,
2046 .busy = scsi_mq_lld_busy,
2047 .map_queues = scsi_map_queues,
2048 .init_hctx = scsi_init_hctx,
2049 .poll = scsi_mq_poll,
2050 .set_rq_budget_token = scsi_mq_set_rq_budget_token,
2051 .get_rq_budget_token = scsi_mq_get_rq_budget_token,
2052};
2053
2054int scsi_mq_setup_tags(struct Scsi_Host *shost)
2055{
2056 unsigned int cmd_size, sgl_size;
2057 struct blk_mq_tag_set *tag_set = &shost->tag_set;
2058
2059 sgl_size = max_t(unsigned int, sizeof(struct scatterlist),
2060 scsi_mq_inline_sgl_size(shost));
2061 cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size;
2062 if (scsi_host_get_prot(shost))
2063 cmd_size += sizeof(struct scsi_data_buffer) +
2064 sizeof(struct scatterlist) * SCSI_INLINE_PROT_SG_CNT;
2065
2066 memset(tag_set, 0, sizeof(*tag_set));
2067 if (shost->hostt->commit_rqs)
2068 tag_set->ops = &scsi_mq_ops;
2069 else
2070 tag_set->ops = &scsi_mq_ops_no_commit;
2071 tag_set->nr_hw_queues = shost->nr_hw_queues ? : 1;
2072 tag_set->nr_maps = shost->nr_maps ? : 1;
2073 tag_set->queue_depth = shost->can_queue;
2074 tag_set->cmd_size = cmd_size;
2075 tag_set->numa_node = dev_to_node(shost->dma_dev);
2076 tag_set->flags = BLK_MQ_F_SHOULD_MERGE;
2077 tag_set->flags |=
2078 BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
2079 if (shost->queuecommand_may_block)
2080 tag_set->flags |= BLK_MQ_F_BLOCKING;
2081 tag_set->driver_data = shost;
2082 if (shost->host_tagset)
2083 tag_set->flags |= BLK_MQ_F_TAG_HCTX_SHARED;
2084
2085 return blk_mq_alloc_tag_set(tag_set);
2086}
2087
2088void scsi_mq_free_tags(struct kref *kref)
2089{
2090 struct Scsi_Host *shost = container_of(kref, typeof(*shost),
2091 tagset_refcnt);
2092
2093 blk_mq_free_tag_set(&shost->tag_set);
2094 complete(&shost->tagset_freed);
2095}
2096
2097/**
2098 * scsi_device_from_queue - return sdev associated with a request_queue
2099 * @q: The request queue to return the sdev from
2100 *
2101 * Return the sdev associated with a request queue or NULL if the
2102 * request_queue does not reference a SCSI device.
2103 */
2104struct scsi_device *scsi_device_from_queue(struct request_queue *q)
2105{
2106 struct scsi_device *sdev = NULL;
2107
2108 if (q->mq_ops == &scsi_mq_ops_no_commit ||
2109 q->mq_ops == &scsi_mq_ops)
2110 sdev = q->queuedata;
2111 if (!sdev || !get_device(&sdev->sdev_gendev))
2112 sdev = NULL;
2113
2114 return sdev;
2115}
2116/*
2117 * pktcdvd should have been integrated into the SCSI layers, but for historical
2118 * reasons like the old IDE driver it isn't. This export allows it to safely
2119 * probe if a given device is a SCSI one and only attach to that.
2120 */
2121#ifdef CONFIG_CDROM_PKTCDVD_MODULE
2122EXPORT_SYMBOL_GPL(scsi_device_from_queue);
2123#endif
2124
2125/**
2126 * scsi_block_requests - Utility function used by low-level drivers to prevent
2127 * further commands from being queued to the device.
2128 * @shost: host in question
2129 *
2130 * There is no timer nor any other means by which the requests get unblocked
2131 * other than the low-level driver calling scsi_unblock_requests().
2132 */
2133void scsi_block_requests(struct Scsi_Host *shost)
2134{
2135 shost->host_self_blocked = 1;
2136}
2137EXPORT_SYMBOL(scsi_block_requests);
2138
2139/**
2140 * scsi_unblock_requests - Utility function used by low-level drivers to allow
2141 * further commands to be queued to the device.
2142 * @shost: host in question
2143 *
2144 * There is no timer nor any other means by which the requests get unblocked
2145 * other than the low-level driver calling scsi_unblock_requests(). This is done
2146 * as an API function so that changes to the internals of the scsi mid-layer
2147 * won't require wholesale changes to drivers that use this feature.
2148 */
2149void scsi_unblock_requests(struct Scsi_Host *shost)
2150{
2151 shost->host_self_blocked = 0;
2152 scsi_run_host_queues(shost);
2153}
2154EXPORT_SYMBOL(scsi_unblock_requests);
2155
2156void scsi_exit_queue(void)
2157{
2158 kmem_cache_destroy(scsi_sense_cache);
2159}
2160
2161/**
2162 * scsi_mode_select - issue a mode select
2163 * @sdev: SCSI device to be queried
2164 * @pf: Page format bit (1 == standard, 0 == vendor specific)
2165 * @sp: Save page bit (0 == don't save, 1 == save)
2166 * @buffer: request buffer (may not be smaller than eight bytes)
2167 * @len: length of request buffer.
2168 * @timeout: command timeout
2169 * @retries: number of retries before failing
2170 * @data: returns a structure abstracting the mode header data
2171 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2172 * must be SCSI_SENSE_BUFFERSIZE big.
2173 *
2174 * Returns zero if successful; negative error number or scsi
2175 * status on error
2176 *
2177 */
2178int scsi_mode_select(struct scsi_device *sdev, int pf, int sp,
2179 unsigned char *buffer, int len, int timeout, int retries,
2180 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2181{
2182 unsigned char cmd[10];
2183 unsigned char *real_buffer;
2184 const struct scsi_exec_args exec_args = {
2185 .sshdr = sshdr,
2186 };
2187 int ret;
2188
2189 memset(cmd, 0, sizeof(cmd));
2190 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
2191
2192 /*
2193 * Use MODE SELECT(10) if the device asked for it or if the mode page
2194 * and the mode select header cannot fit within the maximumm 255 bytes
2195 * of the MODE SELECT(6) command.
2196 */
2197 if (sdev->use_10_for_ms ||
2198 len + 4 > 255 ||
2199 data->block_descriptor_length > 255) {
2200 if (len > 65535 - 8)
2201 return -EINVAL;
2202 real_buffer = kmalloc(8 + len, GFP_KERNEL);
2203 if (!real_buffer)
2204 return -ENOMEM;
2205 memcpy(real_buffer + 8, buffer, len);
2206 len += 8;
2207 real_buffer[0] = 0;
2208 real_buffer[1] = 0;
2209 real_buffer[2] = data->medium_type;
2210 real_buffer[3] = data->device_specific;
2211 real_buffer[4] = data->longlba ? 0x01 : 0;
2212 real_buffer[5] = 0;
2213 put_unaligned_be16(data->block_descriptor_length,
2214 &real_buffer[6]);
2215
2216 cmd[0] = MODE_SELECT_10;
2217 put_unaligned_be16(len, &cmd[7]);
2218 } else {
2219 if (data->longlba)
2220 return -EINVAL;
2221
2222 real_buffer = kmalloc(4 + len, GFP_KERNEL);
2223 if (!real_buffer)
2224 return -ENOMEM;
2225 memcpy(real_buffer + 4, buffer, len);
2226 len += 4;
2227 real_buffer[0] = 0;
2228 real_buffer[1] = data->medium_type;
2229 real_buffer[2] = data->device_specific;
2230 real_buffer[3] = data->block_descriptor_length;
2231
2232 cmd[0] = MODE_SELECT;
2233 cmd[4] = len;
2234 }
2235
2236 ret = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_OUT, real_buffer, len,
2237 timeout, retries, &exec_args);
2238 kfree(real_buffer);
2239 return ret;
2240}
2241EXPORT_SYMBOL_GPL(scsi_mode_select);
2242
2243/**
2244 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
2245 * @sdev: SCSI device to be queried
2246 * @dbd: set to prevent mode sense from returning block descriptors
2247 * @modepage: mode page being requested
2248 * @subpage: sub-page of the mode page being requested
2249 * @buffer: request buffer (may not be smaller than eight bytes)
2250 * @len: length of request buffer.
2251 * @timeout: command timeout
2252 * @retries: number of retries before failing
2253 * @data: returns a structure abstracting the mode header data
2254 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2255 * must be SCSI_SENSE_BUFFERSIZE big.
2256 *
2257 * Returns zero if successful, or a negative error number on failure
2258 */
2259int
2260scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, int subpage,
2261 unsigned char *buffer, int len, int timeout, int retries,
2262 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2263{
2264 unsigned char cmd[12];
2265 int use_10_for_ms;
2266 int header_length;
2267 int result;
2268 struct scsi_sense_hdr my_sshdr;
2269 struct scsi_failure failure_defs[] = {
2270 {
2271 .sense = UNIT_ATTENTION,
2272 .asc = SCMD_FAILURE_ASC_ANY,
2273 .ascq = SCMD_FAILURE_ASCQ_ANY,
2274 .allowed = retries,
2275 .result = SAM_STAT_CHECK_CONDITION,
2276 },
2277 {}
2278 };
2279 struct scsi_failures failures = {
2280 .failure_definitions = failure_defs,
2281 };
2282 const struct scsi_exec_args exec_args = {
2283 /* caller might not be interested in sense, but we need it */
2284 .sshdr = sshdr ? : &my_sshdr,
2285 .failures = &failures,
2286 };
2287
2288 memset(data, 0, sizeof(*data));
2289 memset(&cmd[0], 0, 12);
2290
2291 dbd = sdev->set_dbd_for_ms ? 8 : dbd;
2292 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
2293 cmd[2] = modepage;
2294 cmd[3] = subpage;
2295
2296 sshdr = exec_args.sshdr;
2297
2298 retry:
2299 use_10_for_ms = sdev->use_10_for_ms || len > 255;
2300
2301 if (use_10_for_ms) {
2302 if (len < 8 || len > 65535)
2303 return -EINVAL;
2304
2305 cmd[0] = MODE_SENSE_10;
2306 put_unaligned_be16(len, &cmd[7]);
2307 header_length = 8;
2308 } else {
2309 if (len < 4)
2310 return -EINVAL;
2311
2312 cmd[0] = MODE_SENSE;
2313 cmd[4] = len;
2314 header_length = 4;
2315 }
2316
2317 memset(buffer, 0, len);
2318
2319 result = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_IN, buffer, len,
2320 timeout, retries, &exec_args);
2321 if (result < 0)
2322 return result;
2323
2324 /* This code looks awful: what it's doing is making sure an
2325 * ILLEGAL REQUEST sense return identifies the actual command
2326 * byte as the problem. MODE_SENSE commands can return
2327 * ILLEGAL REQUEST if the code page isn't supported */
2328
2329 if (!scsi_status_is_good(result)) {
2330 if (scsi_sense_valid(sshdr)) {
2331 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
2332 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
2333 /*
2334 * Invalid command operation code: retry using
2335 * MODE SENSE(6) if this was a MODE SENSE(10)
2336 * request, except if the request mode page is
2337 * too large for MODE SENSE single byte
2338 * allocation length field.
2339 */
2340 if (use_10_for_ms) {
2341 if (len > 255)
2342 return -EIO;
2343 sdev->use_10_for_ms = 0;
2344 goto retry;
2345 }
2346 }
2347 }
2348 return -EIO;
2349 }
2350 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
2351 (modepage == 6 || modepage == 8))) {
2352 /* Initio breakage? */
2353 header_length = 0;
2354 data->length = 13;
2355 data->medium_type = 0;
2356 data->device_specific = 0;
2357 data->longlba = 0;
2358 data->block_descriptor_length = 0;
2359 } else if (use_10_for_ms) {
2360 data->length = get_unaligned_be16(&buffer[0]) + 2;
2361 data->medium_type = buffer[2];
2362 data->device_specific = buffer[3];
2363 data->longlba = buffer[4] & 0x01;
2364 data->block_descriptor_length = get_unaligned_be16(&buffer[6]);
2365 } else {
2366 data->length = buffer[0] + 1;
2367 data->medium_type = buffer[1];
2368 data->device_specific = buffer[2];
2369 data->block_descriptor_length = buffer[3];
2370 }
2371 data->header_length = header_length;
2372
2373 return 0;
2374}
2375EXPORT_SYMBOL(scsi_mode_sense);
2376
2377/**
2378 * scsi_test_unit_ready - test if unit is ready
2379 * @sdev: scsi device to change the state of.
2380 * @timeout: command timeout
2381 * @retries: number of retries before failing
2382 * @sshdr: outpout pointer for decoded sense information.
2383 *
2384 * Returns zero if unsuccessful or an error if TUR failed. For
2385 * removable media, UNIT_ATTENTION sets ->changed flag.
2386 **/
2387int
2388scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2389 struct scsi_sense_hdr *sshdr)
2390{
2391 char cmd[] = {
2392 TEST_UNIT_READY, 0, 0, 0, 0, 0,
2393 };
2394 const struct scsi_exec_args exec_args = {
2395 .sshdr = sshdr,
2396 };
2397 int result;
2398
2399 /* try to eat the UNIT_ATTENTION if there are enough retries */
2400 do {
2401 result = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_IN, NULL, 0,
2402 timeout, 1, &exec_args);
2403 if (sdev->removable && result > 0 && scsi_sense_valid(sshdr) &&
2404 sshdr->sense_key == UNIT_ATTENTION)
2405 sdev->changed = 1;
2406 } while (result > 0 && scsi_sense_valid(sshdr) &&
2407 sshdr->sense_key == UNIT_ATTENTION && --retries);
2408
2409 return result;
2410}
2411EXPORT_SYMBOL(scsi_test_unit_ready);
2412
2413/**
2414 * scsi_device_set_state - Take the given device through the device state model.
2415 * @sdev: scsi device to change the state of.
2416 * @state: state to change to.
2417 *
2418 * Returns zero if successful or an error if the requested
2419 * transition is illegal.
2420 */
2421int
2422scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2423{
2424 enum scsi_device_state oldstate = sdev->sdev_state;
2425
2426 if (state == oldstate)
2427 return 0;
2428
2429 switch (state) {
2430 case SDEV_CREATED:
2431 switch (oldstate) {
2432 case SDEV_CREATED_BLOCK:
2433 break;
2434 default:
2435 goto illegal;
2436 }
2437 break;
2438
2439 case SDEV_RUNNING:
2440 switch (oldstate) {
2441 case SDEV_CREATED:
2442 case SDEV_OFFLINE:
2443 case SDEV_TRANSPORT_OFFLINE:
2444 case SDEV_QUIESCE:
2445 case SDEV_BLOCK:
2446 break;
2447 default:
2448 goto illegal;
2449 }
2450 break;
2451
2452 case SDEV_QUIESCE:
2453 switch (oldstate) {
2454 case SDEV_RUNNING:
2455 case SDEV_OFFLINE:
2456 case SDEV_TRANSPORT_OFFLINE:
2457 break;
2458 default:
2459 goto illegal;
2460 }
2461 break;
2462
2463 case SDEV_OFFLINE:
2464 case SDEV_TRANSPORT_OFFLINE:
2465 switch (oldstate) {
2466 case SDEV_CREATED:
2467 case SDEV_RUNNING:
2468 case SDEV_QUIESCE:
2469 case SDEV_BLOCK:
2470 break;
2471 default:
2472 goto illegal;
2473 }
2474 break;
2475
2476 case SDEV_BLOCK:
2477 switch (oldstate) {
2478 case SDEV_RUNNING:
2479 case SDEV_CREATED_BLOCK:
2480 case SDEV_QUIESCE:
2481 case SDEV_OFFLINE:
2482 break;
2483 default:
2484 goto illegal;
2485 }
2486 break;
2487
2488 case SDEV_CREATED_BLOCK:
2489 switch (oldstate) {
2490 case SDEV_CREATED:
2491 break;
2492 default:
2493 goto illegal;
2494 }
2495 break;
2496
2497 case SDEV_CANCEL:
2498 switch (oldstate) {
2499 case SDEV_CREATED:
2500 case SDEV_RUNNING:
2501 case SDEV_QUIESCE:
2502 case SDEV_OFFLINE:
2503 case SDEV_TRANSPORT_OFFLINE:
2504 break;
2505 default:
2506 goto illegal;
2507 }
2508 break;
2509
2510 case SDEV_DEL:
2511 switch (oldstate) {
2512 case SDEV_CREATED:
2513 case SDEV_RUNNING:
2514 case SDEV_OFFLINE:
2515 case SDEV_TRANSPORT_OFFLINE:
2516 case SDEV_CANCEL:
2517 case SDEV_BLOCK:
2518 case SDEV_CREATED_BLOCK:
2519 break;
2520 default:
2521 goto illegal;
2522 }
2523 break;
2524
2525 }
2526 sdev->offline_already = false;
2527 sdev->sdev_state = state;
2528 return 0;
2529
2530 illegal:
2531 SCSI_LOG_ERROR_RECOVERY(1,
2532 sdev_printk(KERN_ERR, sdev,
2533 "Illegal state transition %s->%s",
2534 scsi_device_state_name(oldstate),
2535 scsi_device_state_name(state))
2536 );
2537 return -EINVAL;
2538}
2539EXPORT_SYMBOL(scsi_device_set_state);
2540
2541/**
2542 * scsi_evt_emit - emit a single SCSI device uevent
2543 * @sdev: associated SCSI device
2544 * @evt: event to emit
2545 *
2546 * Send a single uevent (scsi_event) to the associated scsi_device.
2547 */
2548static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2549{
2550 int idx = 0;
2551 char *envp[3];
2552
2553 switch (evt->evt_type) {
2554 case SDEV_EVT_MEDIA_CHANGE:
2555 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2556 break;
2557 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2558 scsi_rescan_device(sdev);
2559 envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2560 break;
2561 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2562 envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2563 break;
2564 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2565 envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2566 break;
2567 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2568 envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2569 break;
2570 case SDEV_EVT_LUN_CHANGE_REPORTED:
2571 envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2572 break;
2573 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2574 envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
2575 break;
2576 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2577 envp[idx++] = "SDEV_UA=POWER_ON_RESET_OCCURRED";
2578 break;
2579 default:
2580 /* do nothing */
2581 break;
2582 }
2583
2584 envp[idx++] = NULL;
2585
2586 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2587}
2588
2589/**
2590 * scsi_evt_thread - send a uevent for each scsi event
2591 * @work: work struct for scsi_device
2592 *
2593 * Dispatch queued events to their associated scsi_device kobjects
2594 * as uevents.
2595 */
2596void scsi_evt_thread(struct work_struct *work)
2597{
2598 struct scsi_device *sdev;
2599 enum scsi_device_event evt_type;
2600 LIST_HEAD(event_list);
2601
2602 sdev = container_of(work, struct scsi_device, event_work);
2603
2604 for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
2605 if (test_and_clear_bit(evt_type, sdev->pending_events))
2606 sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
2607
2608 while (1) {
2609 struct scsi_event *evt;
2610 struct list_head *this, *tmp;
2611 unsigned long flags;
2612
2613 spin_lock_irqsave(&sdev->list_lock, flags);
2614 list_splice_init(&sdev->event_list, &event_list);
2615 spin_unlock_irqrestore(&sdev->list_lock, flags);
2616
2617 if (list_empty(&event_list))
2618 break;
2619
2620 list_for_each_safe(this, tmp, &event_list) {
2621 evt = list_entry(this, struct scsi_event, node);
2622 list_del(&evt->node);
2623 scsi_evt_emit(sdev, evt);
2624 kfree(evt);
2625 }
2626 }
2627}
2628
2629/**
2630 * sdev_evt_send - send asserted event to uevent thread
2631 * @sdev: scsi_device event occurred on
2632 * @evt: event to send
2633 *
2634 * Assert scsi device event asynchronously.
2635 */
2636void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2637{
2638 unsigned long flags;
2639
2640#if 0
2641 /* FIXME: currently this check eliminates all media change events
2642 * for polled devices. Need to update to discriminate between AN
2643 * and polled events */
2644 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2645 kfree(evt);
2646 return;
2647 }
2648#endif
2649
2650 spin_lock_irqsave(&sdev->list_lock, flags);
2651 list_add_tail(&evt->node, &sdev->event_list);
2652 schedule_work(&sdev->event_work);
2653 spin_unlock_irqrestore(&sdev->list_lock, flags);
2654}
2655EXPORT_SYMBOL_GPL(sdev_evt_send);
2656
2657/**
2658 * sdev_evt_alloc - allocate a new scsi event
2659 * @evt_type: type of event to allocate
2660 * @gfpflags: GFP flags for allocation
2661 *
2662 * Allocates and returns a new scsi_event.
2663 */
2664struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2665 gfp_t gfpflags)
2666{
2667 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2668 if (!evt)
2669 return NULL;
2670
2671 evt->evt_type = evt_type;
2672 INIT_LIST_HEAD(&evt->node);
2673
2674 /* evt_type-specific initialization, if any */
2675 switch (evt_type) {
2676 case SDEV_EVT_MEDIA_CHANGE:
2677 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2678 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2679 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2680 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2681 case SDEV_EVT_LUN_CHANGE_REPORTED:
2682 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2683 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2684 default:
2685 /* do nothing */
2686 break;
2687 }
2688
2689 return evt;
2690}
2691EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2692
2693/**
2694 * sdev_evt_send_simple - send asserted event to uevent thread
2695 * @sdev: scsi_device event occurred on
2696 * @evt_type: type of event to send
2697 * @gfpflags: GFP flags for allocation
2698 *
2699 * Assert scsi device event asynchronously, given an event type.
2700 */
2701void sdev_evt_send_simple(struct scsi_device *sdev,
2702 enum scsi_device_event evt_type, gfp_t gfpflags)
2703{
2704 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2705 if (!evt) {
2706 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2707 evt_type);
2708 return;
2709 }
2710
2711 sdev_evt_send(sdev, evt);
2712}
2713EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2714
2715/**
2716 * scsi_device_quiesce - Block all commands except power management.
2717 * @sdev: scsi device to quiesce.
2718 *
2719 * This works by trying to transition to the SDEV_QUIESCE state
2720 * (which must be a legal transition). When the device is in this
2721 * state, only power management requests will be accepted, all others will
2722 * be deferred.
2723 *
2724 * Must be called with user context, may sleep.
2725 *
2726 * Returns zero if unsuccessful or an error if not.
2727 */
2728int
2729scsi_device_quiesce(struct scsi_device *sdev)
2730{
2731 struct request_queue *q = sdev->request_queue;
2732 int err;
2733
2734 /*
2735 * It is allowed to call scsi_device_quiesce() multiple times from
2736 * the same context but concurrent scsi_device_quiesce() calls are
2737 * not allowed.
2738 */
2739 WARN_ON_ONCE(sdev->quiesced_by && sdev->quiesced_by != current);
2740
2741 if (sdev->quiesced_by == current)
2742 return 0;
2743
2744 blk_set_pm_only(q);
2745
2746 blk_mq_freeze_queue(q);
2747 /*
2748 * Ensure that the effect of blk_set_pm_only() will be visible
2749 * for percpu_ref_tryget() callers that occur after the queue
2750 * unfreeze even if the queue was already frozen before this function
2751 * was called. See also https://lwn.net/Articles/573497/.
2752 */
2753 synchronize_rcu();
2754 blk_mq_unfreeze_queue(q);
2755
2756 mutex_lock(&sdev->state_mutex);
2757 err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2758 if (err == 0)
2759 sdev->quiesced_by = current;
2760 else
2761 blk_clear_pm_only(q);
2762 mutex_unlock(&sdev->state_mutex);
2763
2764 return err;
2765}
2766EXPORT_SYMBOL(scsi_device_quiesce);
2767
2768/**
2769 * scsi_device_resume - Restart user issued commands to a quiesced device.
2770 * @sdev: scsi device to resume.
2771 *
2772 * Moves the device from quiesced back to running and restarts the
2773 * queues.
2774 *
2775 * Must be called with user context, may sleep.
2776 */
2777void scsi_device_resume(struct scsi_device *sdev)
2778{
2779 /* check if the device state was mutated prior to resume, and if
2780 * so assume the state is being managed elsewhere (for example
2781 * device deleted during suspend)
2782 */
2783 mutex_lock(&sdev->state_mutex);
2784 if (sdev->sdev_state == SDEV_QUIESCE)
2785 scsi_device_set_state(sdev, SDEV_RUNNING);
2786 if (sdev->quiesced_by) {
2787 sdev->quiesced_by = NULL;
2788 blk_clear_pm_only(sdev->request_queue);
2789 }
2790 mutex_unlock(&sdev->state_mutex);
2791}
2792EXPORT_SYMBOL(scsi_device_resume);
2793
2794static void
2795device_quiesce_fn(struct scsi_device *sdev, void *data)
2796{
2797 scsi_device_quiesce(sdev);
2798}
2799
2800void
2801scsi_target_quiesce(struct scsi_target *starget)
2802{
2803 starget_for_each_device(starget, NULL, device_quiesce_fn);
2804}
2805EXPORT_SYMBOL(scsi_target_quiesce);
2806
2807static void
2808device_resume_fn(struct scsi_device *sdev, void *data)
2809{
2810 scsi_device_resume(sdev);
2811}
2812
2813void
2814scsi_target_resume(struct scsi_target *starget)
2815{
2816 starget_for_each_device(starget, NULL, device_resume_fn);
2817}
2818EXPORT_SYMBOL(scsi_target_resume);
2819
2820static int __scsi_internal_device_block_nowait(struct scsi_device *sdev)
2821{
2822 if (scsi_device_set_state(sdev, SDEV_BLOCK))
2823 return scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2824
2825 return 0;
2826}
2827
2828void scsi_start_queue(struct scsi_device *sdev)
2829{
2830 if (cmpxchg(&sdev->queue_stopped, 1, 0))
2831 blk_mq_unquiesce_queue(sdev->request_queue);
2832}
2833
2834static void scsi_stop_queue(struct scsi_device *sdev)
2835{
2836 /*
2837 * The atomic variable of ->queue_stopped covers that
2838 * blk_mq_quiesce_queue* is balanced with blk_mq_unquiesce_queue.
2839 *
2840 * The caller needs to wait until quiesce is done.
2841 */
2842 if (!cmpxchg(&sdev->queue_stopped, 0, 1))
2843 blk_mq_quiesce_queue_nowait(sdev->request_queue);
2844}
2845
2846/**
2847 * scsi_internal_device_block_nowait - try to transition to the SDEV_BLOCK state
2848 * @sdev: device to block
2849 *
2850 * Pause SCSI command processing on the specified device. Does not sleep.
2851 *
2852 * Returns zero if successful or a negative error code upon failure.
2853 *
2854 * Notes:
2855 * This routine transitions the device to the SDEV_BLOCK state (which must be
2856 * a legal transition). When the device is in this state, command processing
2857 * is paused until the device leaves the SDEV_BLOCK state. See also
2858 * scsi_internal_device_unblock_nowait().
2859 */
2860int scsi_internal_device_block_nowait(struct scsi_device *sdev)
2861{
2862 int ret = __scsi_internal_device_block_nowait(sdev);
2863
2864 /*
2865 * The device has transitioned to SDEV_BLOCK. Stop the
2866 * block layer from calling the midlayer with this device's
2867 * request queue.
2868 */
2869 if (!ret)
2870 scsi_stop_queue(sdev);
2871 return ret;
2872}
2873EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait);
2874
2875/**
2876 * scsi_device_block - try to transition to the SDEV_BLOCK state
2877 * @sdev: device to block
2878 * @data: dummy argument, ignored
2879 *
2880 * Pause SCSI command processing on the specified device. Callers must wait
2881 * until all ongoing scsi_queue_rq() calls have finished after this function
2882 * returns.
2883 *
2884 * Note:
2885 * This routine transitions the device to the SDEV_BLOCK state (which must be
2886 * a legal transition). When the device is in this state, command processing
2887 * is paused until the device leaves the SDEV_BLOCK state. See also
2888 * scsi_internal_device_unblock().
2889 */
2890static void scsi_device_block(struct scsi_device *sdev, void *data)
2891{
2892 int err;
2893 enum scsi_device_state state;
2894
2895 mutex_lock(&sdev->state_mutex);
2896 err = __scsi_internal_device_block_nowait(sdev);
2897 state = sdev->sdev_state;
2898 if (err == 0)
2899 /*
2900 * scsi_stop_queue() must be called with the state_mutex
2901 * held. Otherwise a simultaneous scsi_start_queue() call
2902 * might unquiesce the queue before we quiesce it.
2903 */
2904 scsi_stop_queue(sdev);
2905
2906 mutex_unlock(&sdev->state_mutex);
2907
2908 WARN_ONCE(err, "%s: failed to block %s in state %d\n",
2909 __func__, dev_name(&sdev->sdev_gendev), state);
2910}
2911
2912/**
2913 * scsi_internal_device_unblock_nowait - resume a device after a block request
2914 * @sdev: device to resume
2915 * @new_state: state to set the device to after unblocking
2916 *
2917 * Restart the device queue for a previously suspended SCSI device. Does not
2918 * sleep.
2919 *
2920 * Returns zero if successful or a negative error code upon failure.
2921 *
2922 * Notes:
2923 * This routine transitions the device to the SDEV_RUNNING state or to one of
2924 * the offline states (which must be a legal transition) allowing the midlayer
2925 * to goose the queue for this device.
2926 */
2927int scsi_internal_device_unblock_nowait(struct scsi_device *sdev,
2928 enum scsi_device_state new_state)
2929{
2930 switch (new_state) {
2931 case SDEV_RUNNING:
2932 case SDEV_TRANSPORT_OFFLINE:
2933 break;
2934 default:
2935 return -EINVAL;
2936 }
2937
2938 /*
2939 * Try to transition the scsi device to SDEV_RUNNING or one of the
2940 * offlined states and goose the device queue if successful.
2941 */
2942 switch (sdev->sdev_state) {
2943 case SDEV_BLOCK:
2944 case SDEV_TRANSPORT_OFFLINE:
2945 sdev->sdev_state = new_state;
2946 break;
2947 case SDEV_CREATED_BLOCK:
2948 if (new_state == SDEV_TRANSPORT_OFFLINE ||
2949 new_state == SDEV_OFFLINE)
2950 sdev->sdev_state = new_state;
2951 else
2952 sdev->sdev_state = SDEV_CREATED;
2953 break;
2954 case SDEV_CANCEL:
2955 case SDEV_OFFLINE:
2956 break;
2957 default:
2958 return -EINVAL;
2959 }
2960 scsi_start_queue(sdev);
2961
2962 return 0;
2963}
2964EXPORT_SYMBOL_GPL(scsi_internal_device_unblock_nowait);
2965
2966/**
2967 * scsi_internal_device_unblock - resume a device after a block request
2968 * @sdev: device to resume
2969 * @new_state: state to set the device to after unblocking
2970 *
2971 * Restart the device queue for a previously suspended SCSI device. May sleep.
2972 *
2973 * Returns zero if successful or a negative error code upon failure.
2974 *
2975 * Notes:
2976 * This routine transitions the device to the SDEV_RUNNING state or to one of
2977 * the offline states (which must be a legal transition) allowing the midlayer
2978 * to goose the queue for this device.
2979 */
2980static int scsi_internal_device_unblock(struct scsi_device *sdev,
2981 enum scsi_device_state new_state)
2982{
2983 int ret;
2984
2985 mutex_lock(&sdev->state_mutex);
2986 ret = scsi_internal_device_unblock_nowait(sdev, new_state);
2987 mutex_unlock(&sdev->state_mutex);
2988
2989 return ret;
2990}
2991
2992static int
2993target_block(struct device *dev, void *data)
2994{
2995 if (scsi_is_target_device(dev))
2996 starget_for_each_device(to_scsi_target(dev), NULL,
2997 scsi_device_block);
2998 return 0;
2999}
3000
3001/**
3002 * scsi_block_targets - transition all SCSI child devices to SDEV_BLOCK state
3003 * @dev: a parent device of one or more scsi_target devices
3004 * @shost: the Scsi_Host to which this device belongs
3005 *
3006 * Iterate over all children of @dev, which should be scsi_target devices,
3007 * and switch all subordinate scsi devices to SDEV_BLOCK state. Wait for
3008 * ongoing scsi_queue_rq() calls to finish. May sleep.
3009 *
3010 * Note:
3011 * @dev must not itself be a scsi_target device.
3012 */
3013void
3014scsi_block_targets(struct Scsi_Host *shost, struct device *dev)
3015{
3016 WARN_ON_ONCE(scsi_is_target_device(dev));
3017 device_for_each_child(dev, NULL, target_block);
3018 blk_mq_wait_quiesce_done(&shost->tag_set);
3019}
3020EXPORT_SYMBOL_GPL(scsi_block_targets);
3021
3022static void
3023device_unblock(struct scsi_device *sdev, void *data)
3024{
3025 scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
3026}
3027
3028static int
3029target_unblock(struct device *dev, void *data)
3030{
3031 if (scsi_is_target_device(dev))
3032 starget_for_each_device(to_scsi_target(dev), data,
3033 device_unblock);
3034 return 0;
3035}
3036
3037void
3038scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
3039{
3040 if (scsi_is_target_device(dev))
3041 starget_for_each_device(to_scsi_target(dev), &new_state,
3042 device_unblock);
3043 else
3044 device_for_each_child(dev, &new_state, target_unblock);
3045}
3046EXPORT_SYMBOL_GPL(scsi_target_unblock);
3047
3048/**
3049 * scsi_host_block - Try to transition all logical units to the SDEV_BLOCK state
3050 * @shost: device to block
3051 *
3052 * Pause SCSI command processing for all logical units associated with the SCSI
3053 * host and wait until pending scsi_queue_rq() calls have finished.
3054 *
3055 * Returns zero if successful or a negative error code upon failure.
3056 */
3057int
3058scsi_host_block(struct Scsi_Host *shost)
3059{
3060 struct scsi_device *sdev;
3061 int ret;
3062
3063 /*
3064 * Call scsi_internal_device_block_nowait so we can avoid
3065 * calling synchronize_rcu() for each LUN.
3066 */
3067 shost_for_each_device(sdev, shost) {
3068 mutex_lock(&sdev->state_mutex);
3069 ret = scsi_internal_device_block_nowait(sdev);
3070 mutex_unlock(&sdev->state_mutex);
3071 if (ret) {
3072 scsi_device_put(sdev);
3073 return ret;
3074 }
3075 }
3076
3077 /* Wait for ongoing scsi_queue_rq() calls to finish. */
3078 blk_mq_wait_quiesce_done(&shost->tag_set);
3079
3080 return 0;
3081}
3082EXPORT_SYMBOL_GPL(scsi_host_block);
3083
3084int
3085scsi_host_unblock(struct Scsi_Host *shost, int new_state)
3086{
3087 struct scsi_device *sdev;
3088 int ret = 0;
3089
3090 shost_for_each_device(sdev, shost) {
3091 ret = scsi_internal_device_unblock(sdev, new_state);
3092 if (ret) {
3093 scsi_device_put(sdev);
3094 break;
3095 }
3096 }
3097 return ret;
3098}
3099EXPORT_SYMBOL_GPL(scsi_host_unblock);
3100
3101/**
3102 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
3103 * @sgl: scatter-gather list
3104 * @sg_count: number of segments in sg
3105 * @offset: offset in bytes into sg, on return offset into the mapped area
3106 * @len: bytes to map, on return number of bytes mapped
3107 *
3108 * Returns virtual address of the start of the mapped page
3109 */
3110void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
3111 size_t *offset, size_t *len)
3112{
3113 int i;
3114 size_t sg_len = 0, len_complete = 0;
3115 struct scatterlist *sg;
3116 struct page *page;
3117
3118 WARN_ON(!irqs_disabled());
3119
3120 for_each_sg(sgl, sg, sg_count, i) {
3121 len_complete = sg_len; /* Complete sg-entries */
3122 sg_len += sg->length;
3123 if (sg_len > *offset)
3124 break;
3125 }
3126
3127 if (unlikely(i == sg_count)) {
3128 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
3129 "elements %d\n",
3130 __func__, sg_len, *offset, sg_count);
3131 WARN_ON(1);
3132 return NULL;
3133 }
3134
3135 /* Offset starting from the beginning of first page in this sg-entry */
3136 *offset = *offset - len_complete + sg->offset;
3137
3138 /* Assumption: contiguous pages can be accessed as "page + i" */
3139 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
3140 *offset &= ~PAGE_MASK;
3141
3142 /* Bytes in this sg-entry from *offset to the end of the page */
3143 sg_len = PAGE_SIZE - *offset;
3144 if (*len > sg_len)
3145 *len = sg_len;
3146
3147 return kmap_atomic(page);
3148}
3149EXPORT_SYMBOL(scsi_kmap_atomic_sg);
3150
3151/**
3152 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
3153 * @virt: virtual address to be unmapped
3154 */
3155void scsi_kunmap_atomic_sg(void *virt)
3156{
3157 kunmap_atomic(virt);
3158}
3159EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
3160
3161void sdev_disable_disk_events(struct scsi_device *sdev)
3162{
3163 atomic_inc(&sdev->disk_events_disable_depth);
3164}
3165EXPORT_SYMBOL(sdev_disable_disk_events);
3166
3167void sdev_enable_disk_events(struct scsi_device *sdev)
3168{
3169 if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0))
3170 return;
3171 atomic_dec(&sdev->disk_events_disable_depth);
3172}
3173EXPORT_SYMBOL(sdev_enable_disk_events);
3174
3175static unsigned char designator_prio(const unsigned char *d)
3176{
3177 if (d[1] & 0x30)
3178 /* not associated with LUN */
3179 return 0;
3180
3181 if (d[3] == 0)
3182 /* invalid length */
3183 return 0;
3184
3185 /*
3186 * Order of preference for lun descriptor:
3187 * - SCSI name string
3188 * - NAA IEEE Registered Extended
3189 * - EUI-64 based 16-byte
3190 * - EUI-64 based 12-byte
3191 * - NAA IEEE Registered
3192 * - NAA IEEE Extended
3193 * - EUI-64 based 8-byte
3194 * - SCSI name string (truncated)
3195 * - T10 Vendor ID
3196 * as longer descriptors reduce the likelyhood
3197 * of identification clashes.
3198 */
3199
3200 switch (d[1] & 0xf) {
3201 case 8:
3202 /* SCSI name string, variable-length UTF-8 */
3203 return 9;
3204 case 3:
3205 switch (d[4] >> 4) {
3206 case 6:
3207 /* NAA registered extended */
3208 return 8;
3209 case 5:
3210 /* NAA registered */
3211 return 5;
3212 case 4:
3213 /* NAA extended */
3214 return 4;
3215 case 3:
3216 /* NAA locally assigned */
3217 return 1;
3218 default:
3219 break;
3220 }
3221 break;
3222 case 2:
3223 switch (d[3]) {
3224 case 16:
3225 /* EUI64-based, 16 byte */
3226 return 7;
3227 case 12:
3228 /* EUI64-based, 12 byte */
3229 return 6;
3230 case 8:
3231 /* EUI64-based, 8 byte */
3232 return 3;
3233 default:
3234 break;
3235 }
3236 break;
3237 case 1:
3238 /* T10 vendor ID */
3239 return 1;
3240 default:
3241 break;
3242 }
3243
3244 return 0;
3245}
3246
3247/**
3248 * scsi_vpd_lun_id - return a unique device identification
3249 * @sdev: SCSI device
3250 * @id: buffer for the identification
3251 * @id_len: length of the buffer
3252 *
3253 * Copies a unique device identification into @id based
3254 * on the information in the VPD page 0x83 of the device.
3255 * The string will be formatted as a SCSI name string.
3256 *
3257 * Returns the length of the identification or error on failure.
3258 * If the identifier is longer than the supplied buffer the actual
3259 * identifier length is returned and the buffer is not zero-padded.
3260 */
3261int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len)
3262{
3263 u8 cur_id_prio = 0;
3264 u8 cur_id_size = 0;
3265 const unsigned char *d, *cur_id_str;
3266 const struct scsi_vpd *vpd_pg83;
3267 int id_size = -EINVAL;
3268
3269 rcu_read_lock();
3270 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3271 if (!vpd_pg83) {
3272 rcu_read_unlock();
3273 return -ENXIO;
3274 }
3275
3276 /* The id string must be at least 20 bytes + terminating NULL byte */
3277 if (id_len < 21) {
3278 rcu_read_unlock();
3279 return -EINVAL;
3280 }
3281
3282 memset(id, 0, id_len);
3283 for (d = vpd_pg83->data + 4;
3284 d < vpd_pg83->data + vpd_pg83->len;
3285 d += d[3] + 4) {
3286 u8 prio = designator_prio(d);
3287
3288 if (prio == 0 || cur_id_prio > prio)
3289 continue;
3290
3291 switch (d[1] & 0xf) {
3292 case 0x1:
3293 /* T10 Vendor ID */
3294 if (cur_id_size > d[3])
3295 break;
3296 cur_id_prio = prio;
3297 cur_id_size = d[3];
3298 if (cur_id_size + 4 > id_len)
3299 cur_id_size = id_len - 4;
3300 cur_id_str = d + 4;
3301 id_size = snprintf(id, id_len, "t10.%*pE",
3302 cur_id_size, cur_id_str);
3303 break;
3304 case 0x2:
3305 /* EUI-64 */
3306 cur_id_prio = prio;
3307 cur_id_size = d[3];
3308 cur_id_str = d + 4;
3309 switch (cur_id_size) {
3310 case 8:
3311 id_size = snprintf(id, id_len,
3312 "eui.%8phN",
3313 cur_id_str);
3314 break;
3315 case 12:
3316 id_size = snprintf(id, id_len,
3317 "eui.%12phN",
3318 cur_id_str);
3319 break;
3320 case 16:
3321 id_size = snprintf(id, id_len,
3322 "eui.%16phN",
3323 cur_id_str);
3324 break;
3325 default:
3326 break;
3327 }
3328 break;
3329 case 0x3:
3330 /* NAA */
3331 cur_id_prio = prio;
3332 cur_id_size = d[3];
3333 cur_id_str = d + 4;
3334 switch (cur_id_size) {
3335 case 8:
3336 id_size = snprintf(id, id_len,
3337 "naa.%8phN",
3338 cur_id_str);
3339 break;
3340 case 16:
3341 id_size = snprintf(id, id_len,
3342 "naa.%16phN",
3343 cur_id_str);
3344 break;
3345 default:
3346 break;
3347 }
3348 break;
3349 case 0x8:
3350 /* SCSI name string */
3351 if (cur_id_size > d[3])
3352 break;
3353 /* Prefer others for truncated descriptor */
3354 if (d[3] > id_len) {
3355 prio = 2;
3356 if (cur_id_prio > prio)
3357 break;
3358 }
3359 cur_id_prio = prio;
3360 cur_id_size = id_size = d[3];
3361 cur_id_str = d + 4;
3362 if (cur_id_size >= id_len)
3363 cur_id_size = id_len - 1;
3364 memcpy(id, cur_id_str, cur_id_size);
3365 break;
3366 default:
3367 break;
3368 }
3369 }
3370 rcu_read_unlock();
3371
3372 return id_size;
3373}
3374EXPORT_SYMBOL(scsi_vpd_lun_id);
3375
3376/*
3377 * scsi_vpd_tpg_id - return a target port group identifier
3378 * @sdev: SCSI device
3379 *
3380 * Returns the Target Port Group identifier from the information
3381 * froom VPD page 0x83 of the device.
3382 *
3383 * Returns the identifier or error on failure.
3384 */
3385int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id)
3386{
3387 const unsigned char *d;
3388 const struct scsi_vpd *vpd_pg83;
3389 int group_id = -EAGAIN, rel_port = -1;
3390
3391 rcu_read_lock();
3392 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3393 if (!vpd_pg83) {
3394 rcu_read_unlock();
3395 return -ENXIO;
3396 }
3397
3398 d = vpd_pg83->data + 4;
3399 while (d < vpd_pg83->data + vpd_pg83->len) {
3400 switch (d[1] & 0xf) {
3401 case 0x4:
3402 /* Relative target port */
3403 rel_port = get_unaligned_be16(&d[6]);
3404 break;
3405 case 0x5:
3406 /* Target port group */
3407 group_id = get_unaligned_be16(&d[6]);
3408 break;
3409 default:
3410 break;
3411 }
3412 d += d[3] + 4;
3413 }
3414 rcu_read_unlock();
3415
3416 if (group_id >= 0 && rel_id && rel_port != -1)
3417 *rel_id = rel_port;
3418
3419 return group_id;
3420}
3421EXPORT_SYMBOL(scsi_vpd_tpg_id);
3422
3423/**
3424 * scsi_build_sense - build sense data for a command
3425 * @scmd: scsi command for which the sense should be formatted
3426 * @desc: Sense format (non-zero == descriptor format,
3427 * 0 == fixed format)
3428 * @key: Sense key
3429 * @asc: Additional sense code
3430 * @ascq: Additional sense code qualifier
3431 *
3432 **/
3433void scsi_build_sense(struct scsi_cmnd *scmd, int desc, u8 key, u8 asc, u8 ascq)
3434{
3435 scsi_build_sense_buffer(desc, scmd->sense_buffer, key, asc, ascq);
3436 scmd->result = SAM_STAT_CHECK_CONDITION;
3437}
3438EXPORT_SYMBOL_GPL(scsi_build_sense);
3439
3440#ifdef CONFIG_SCSI_LIB_KUNIT_TEST
3441#include "scsi_lib_test.c"
3442#endif