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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 1999 Eric Youngdale
4 * Copyright (C) 2014 Christoph Hellwig
5 *
6 * SCSI queueing library.
7 * Initial versions: Eric Youngdale (eric@andante.org).
8 * Based upon conversations with large numbers
9 * of people at Linux Expo.
10 */
11
12#include <linux/bio.h>
13#include <linux/bitops.h>
14#include <linux/blkdev.h>
15#include <linux/completion.h>
16#include <linux/kernel.h>
17#include <linux/export.h>
18#include <linux/init.h>
19#include <linux/pci.h>
20#include <linux/delay.h>
21#include <linux/hardirq.h>
22#include <linux/scatterlist.h>
23#include <linux/blk-mq.h>
24#include <linux/blk-integrity.h>
25#include <linux/ratelimit.h>
26#include <asm/unaligned.h>
27
28#include <scsi/scsi.h>
29#include <scsi/scsi_cmnd.h>
30#include <scsi/scsi_dbg.h>
31#include <scsi/scsi_device.h>
32#include <scsi/scsi_driver.h>
33#include <scsi/scsi_eh.h>
34#include <scsi/scsi_host.h>
35#include <scsi/scsi_transport.h> /* __scsi_init_queue() */
36#include <scsi/scsi_dh.h>
37
38#include <trace/events/scsi.h>
39
40#include "scsi_debugfs.h"
41#include "scsi_priv.h"
42#include "scsi_logging.h"
43
44/*
45 * Size of integrity metadata is usually small, 1 inline sg should
46 * cover normal cases.
47 */
48#ifdef CONFIG_ARCH_NO_SG_CHAIN
49#define SCSI_INLINE_PROT_SG_CNT 0
50#define SCSI_INLINE_SG_CNT 0
51#else
52#define SCSI_INLINE_PROT_SG_CNT 1
53#define SCSI_INLINE_SG_CNT 2
54#endif
55
56static struct kmem_cache *scsi_sense_cache;
57static DEFINE_MUTEX(scsi_sense_cache_mutex);
58
59static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd);
60
61int scsi_init_sense_cache(struct Scsi_Host *shost)
62{
63 int ret = 0;
64
65 mutex_lock(&scsi_sense_cache_mutex);
66 if (!scsi_sense_cache) {
67 scsi_sense_cache =
68 kmem_cache_create_usercopy("scsi_sense_cache",
69 SCSI_SENSE_BUFFERSIZE, 0, SLAB_HWCACHE_ALIGN,
70 0, SCSI_SENSE_BUFFERSIZE, NULL);
71 if (!scsi_sense_cache)
72 ret = -ENOMEM;
73 }
74 mutex_unlock(&scsi_sense_cache_mutex);
75 return ret;
76}
77
78static void
79scsi_set_blocked(struct scsi_cmnd *cmd, int reason)
80{
81 struct Scsi_Host *host = cmd->device->host;
82 struct scsi_device *device = cmd->device;
83 struct scsi_target *starget = scsi_target(device);
84
85 /*
86 * Set the appropriate busy bit for the device/host.
87 *
88 * If the host/device isn't busy, assume that something actually
89 * completed, and that we should be able to queue a command now.
90 *
91 * Note that the prior mid-layer assumption that any host could
92 * always queue at least one command is now broken. The mid-layer
93 * will implement a user specifiable stall (see
94 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
95 * if a command is requeued with no other commands outstanding
96 * either for the device or for the host.
97 */
98 switch (reason) {
99 case SCSI_MLQUEUE_HOST_BUSY:
100 atomic_set(&host->host_blocked, host->max_host_blocked);
101 break;
102 case SCSI_MLQUEUE_DEVICE_BUSY:
103 case SCSI_MLQUEUE_EH_RETRY:
104 atomic_set(&device->device_blocked,
105 device->max_device_blocked);
106 break;
107 case SCSI_MLQUEUE_TARGET_BUSY:
108 atomic_set(&starget->target_blocked,
109 starget->max_target_blocked);
110 break;
111 }
112}
113
114static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd, unsigned long msecs)
115{
116 struct request *rq = scsi_cmd_to_rq(cmd);
117
118 if (rq->rq_flags & RQF_DONTPREP) {
119 rq->rq_flags &= ~RQF_DONTPREP;
120 scsi_mq_uninit_cmd(cmd);
121 } else {
122 WARN_ON_ONCE(true);
123 }
124
125 blk_mq_requeue_request(rq, false);
126 if (!scsi_host_in_recovery(cmd->device->host))
127 blk_mq_delay_kick_requeue_list(rq->q, msecs);
128}
129
130/**
131 * __scsi_queue_insert - private queue insertion
132 * @cmd: The SCSI command being requeued
133 * @reason: The reason for the requeue
134 * @unbusy: Whether the queue should be unbusied
135 *
136 * This is a private queue insertion. The public interface
137 * scsi_queue_insert() always assumes the queue should be unbusied
138 * because it's always called before the completion. This function is
139 * for a requeue after completion, which should only occur in this
140 * file.
141 */
142static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy)
143{
144 struct scsi_device *device = cmd->device;
145
146 SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd,
147 "Inserting command %p into mlqueue\n", cmd));
148
149 scsi_set_blocked(cmd, reason);
150
151 /*
152 * Decrement the counters, since these commands are no longer
153 * active on the host/device.
154 */
155 if (unbusy)
156 scsi_device_unbusy(device, cmd);
157
158 /*
159 * Requeue this command. It will go before all other commands
160 * that are already in the queue. Schedule requeue work under
161 * lock such that the kblockd_schedule_work() call happens
162 * before blk_mq_destroy_queue() finishes.
163 */
164 cmd->result = 0;
165
166 blk_mq_requeue_request(scsi_cmd_to_rq(cmd),
167 !scsi_host_in_recovery(cmd->device->host));
168}
169
170/**
171 * scsi_queue_insert - Reinsert a command in the queue.
172 * @cmd: command that we are adding to queue.
173 * @reason: why we are inserting command to queue.
174 *
175 * We do this for one of two cases. Either the host is busy and it cannot accept
176 * any more commands for the time being, or the device returned QUEUE_FULL and
177 * can accept no more commands.
178 *
179 * Context: This could be called either from an interrupt context or a normal
180 * process context.
181 */
182void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
183{
184 __scsi_queue_insert(cmd, reason, true);
185}
186
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/ratelimit.h>
25#include <asm/unaligned.h>
26
27#include <scsi/scsi.h>
28#include <scsi/scsi_cmnd.h>
29#include <scsi/scsi_dbg.h>
30#include <scsi/scsi_device.h>
31#include <scsi/scsi_driver.h>
32#include <scsi/scsi_eh.h>
33#include <scsi/scsi_host.h>
34#include <scsi/scsi_transport.h> /* __scsi_init_queue() */
35#include <scsi/scsi_dh.h>
36
37#include <trace/events/scsi.h>
38
39#include "scsi_debugfs.h"
40#include "scsi_priv.h"
41#include "scsi_logging.h"
42
43/*
44 * Size of integrity metadata is usually small, 1 inline sg should
45 * cover normal cases.
46 */
47#ifdef CONFIG_ARCH_NO_SG_CHAIN
48#define SCSI_INLINE_PROT_SG_CNT 0
49#define SCSI_INLINE_SG_CNT 0
50#else
51#define SCSI_INLINE_PROT_SG_CNT 1
52#define SCSI_INLINE_SG_CNT 2
53#endif
54
55static struct kmem_cache *scsi_sdb_cache;
56static struct kmem_cache *scsi_sense_cache;
57static struct kmem_cache *scsi_sense_isadma_cache;
58static DEFINE_MUTEX(scsi_sense_cache_mutex);
59
60static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd);
61
62static inline struct kmem_cache *
63scsi_select_sense_cache(bool unchecked_isa_dma)
64{
65 return unchecked_isa_dma ? scsi_sense_isadma_cache : scsi_sense_cache;
66}
67
68static void scsi_free_sense_buffer(bool unchecked_isa_dma,
69 unsigned char *sense_buffer)
70{
71 kmem_cache_free(scsi_select_sense_cache(unchecked_isa_dma),
72 sense_buffer);
73}
74
75static unsigned char *scsi_alloc_sense_buffer(bool unchecked_isa_dma,
76 gfp_t gfp_mask, int numa_node)
77{
78 return kmem_cache_alloc_node(scsi_select_sense_cache(unchecked_isa_dma),
79 gfp_mask, numa_node);
80}
81
82int scsi_init_sense_cache(struct Scsi_Host *shost)
83{
84 struct kmem_cache *cache;
85 int ret = 0;
86
87 mutex_lock(&scsi_sense_cache_mutex);
88 cache = scsi_select_sense_cache(shost->unchecked_isa_dma);
89 if (cache)
90 goto exit;
91
92 if (shost->unchecked_isa_dma) {
93 scsi_sense_isadma_cache =
94 kmem_cache_create("scsi_sense_cache(DMA)",
95 SCSI_SENSE_BUFFERSIZE, 0,
96 SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA, NULL);
97 if (!scsi_sense_isadma_cache)
98 ret = -ENOMEM;
99 } else {
100 scsi_sense_cache =
101 kmem_cache_create_usercopy("scsi_sense_cache",
102 SCSI_SENSE_BUFFERSIZE, 0, SLAB_HWCACHE_ALIGN,
103 0, SCSI_SENSE_BUFFERSIZE, NULL);
104 if (!scsi_sense_cache)
105 ret = -ENOMEM;
106 }
107 exit:
108 mutex_unlock(&scsi_sense_cache_mutex);
109 return ret;
110}
111
112/*
113 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
114 * not change behaviour from the previous unplug mechanism, experimentation
115 * may prove this needs changing.
116 */
117#define SCSI_QUEUE_DELAY 3
118
119static void
120scsi_set_blocked(struct scsi_cmnd *cmd, int reason)
121{
122 struct Scsi_Host *host = cmd->device->host;
123 struct scsi_device *device = cmd->device;
124 struct scsi_target *starget = scsi_target(device);
125
126 /*
127 * Set the appropriate busy bit for the device/host.
128 *
129 * If the host/device isn't busy, assume that something actually
130 * completed, and that we should be able to queue a command now.
131 *
132 * Note that the prior mid-layer assumption that any host could
133 * always queue at least one command is now broken. The mid-layer
134 * will implement a user specifiable stall (see
135 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
136 * if a command is requeued with no other commands outstanding
137 * either for the device or for the host.
138 */
139 switch (reason) {
140 case SCSI_MLQUEUE_HOST_BUSY:
141 atomic_set(&host->host_blocked, host->max_host_blocked);
142 break;
143 case SCSI_MLQUEUE_DEVICE_BUSY:
144 case SCSI_MLQUEUE_EH_RETRY:
145 atomic_set(&device->device_blocked,
146 device->max_device_blocked);
147 break;
148 case SCSI_MLQUEUE_TARGET_BUSY:
149 atomic_set(&starget->target_blocked,
150 starget->max_target_blocked);
151 break;
152 }
153}
154
155static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd)
156{
157 if (cmd->request->rq_flags & RQF_DONTPREP) {
158 cmd->request->rq_flags &= ~RQF_DONTPREP;
159 scsi_mq_uninit_cmd(cmd);
160 } else {
161 WARN_ON_ONCE(true);
162 }
163 blk_mq_requeue_request(cmd->request, true);
164}
165
166/**
167 * __scsi_queue_insert - private queue insertion
168 * @cmd: The SCSI command being requeued
169 * @reason: The reason for the requeue
170 * @unbusy: Whether the queue should be unbusied
171 *
172 * This is a private queue insertion. The public interface
173 * scsi_queue_insert() always assumes the queue should be unbusied
174 * because it's always called before the completion. This function is
175 * for a requeue after completion, which should only occur in this
176 * file.
177 */
178static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy)
179{
180 struct scsi_device *device = cmd->device;
181
182 SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd,
183 "Inserting command %p into mlqueue\n", cmd));
184
185 scsi_set_blocked(cmd, reason);
186
187 /*
188 * Decrement the counters, since these commands are no longer
189 * active on the host/device.
190 */
191 if (unbusy)
192 scsi_device_unbusy(device);
193
194 /*
195 * Requeue this command. It will go before all other commands
196 * that are already in the queue. Schedule requeue work under
197 * lock such that the kblockd_schedule_work() call happens
198 * before blk_cleanup_queue() finishes.
199 */
200 cmd->result = 0;
201
202 blk_mq_requeue_request(cmd->request, true);
203}
204
205/*
206 * Function: scsi_queue_insert()
207 *
208 * Purpose: Insert a command in the midlevel queue.
209 *
210 * Arguments: cmd - command that we are adding to queue.
211 * reason - why we are inserting command to queue.
212 *
213 * Lock status: Assumed that lock is not held upon entry.
214 *
215 * Returns: Nothing.
216 *
217 * Notes: We do this for one of two cases. Either the host is busy
218 * and it cannot accept any more commands for the time being,
219 * or the device returned QUEUE_FULL and can accept no more
220 * commands.
221 * Notes: This could be called either from an interrupt context or a
222 * normal process context.
223 */
224void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
225{
226 __scsi_queue_insert(cmd, reason, true);
227}
228
229
230/**
231 * __scsi_execute - insert request and wait for the result
232 * @sdev: scsi device
233 * @cmd: scsi command
234 * @data_direction: data direction
235 * @buffer: data buffer
236 * @bufflen: len of buffer
237 * @sense: optional sense buffer
238 * @sshdr: optional decoded sense header
239 * @timeout: request timeout in seconds
240 * @retries: number of times to retry request
241 * @flags: flags for ->cmd_flags
242 * @rq_flags: flags for ->rq_flags
243 * @resid: optional residual length
244 *
245 * Returns the scsi_cmnd result field if a command was executed, or a negative
246 * Linux error code if we didn't get that far.
247 */
248int __scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
249 int data_direction, void *buffer, unsigned bufflen,
250 unsigned char *sense, struct scsi_sense_hdr *sshdr,
251 int timeout, int retries, u64 flags, req_flags_t rq_flags,
252 int *resid)
253{
254 struct request *req;
255 struct scsi_request *rq;
256 int ret = DRIVER_ERROR << 24;
257
258 req = blk_get_request(sdev->request_queue,
259 data_direction == DMA_TO_DEVICE ?
260 REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, BLK_MQ_REQ_PREEMPT);
261 if (IS_ERR(req))
262 return ret;
263 rq = scsi_req(req);
264
265 if (bufflen && blk_rq_map_kern(sdev->request_queue, req,
266 buffer, bufflen, GFP_NOIO))
267 goto out;
268
269 rq->cmd_len = COMMAND_SIZE(cmd[0]);
270 memcpy(rq->cmd, cmd, rq->cmd_len);
271 rq->retries = retries;
272 req->timeout = timeout;
273 req->cmd_flags |= flags;
274 req->rq_flags |= rq_flags | RQF_QUIET;
275
276 /*
277 * head injection *required* here otherwise quiesce won't work
278 */
279 blk_execute_rq(req->q, NULL, req, 1);
280
281 /*
282 * Some devices (USB mass-storage in particular) may transfer
283 * garbage data together with a residue indicating that the data
284 * is invalid. Prevent the garbage from being misinterpreted
285 * and prevent security leaks by zeroing out the excess data.
286 */
287 if (unlikely(rq->resid_len > 0 && rq->resid_len <= bufflen))
288 memset(buffer + (bufflen - rq->resid_len), 0, rq->resid_len);
289
290 if (resid)
291 *resid = rq->resid_len;
292 if (sense && rq->sense_len)
293 memcpy(sense, rq->sense, SCSI_SENSE_BUFFERSIZE);
294 if (sshdr)
295 scsi_normalize_sense(rq->sense, rq->sense_len, sshdr);
296 ret = rq->result;
297 out:
298 blk_put_request(req);
299
300 return ret;
301}
302EXPORT_SYMBOL(__scsi_execute);
303
304/*
305 * Function: scsi_init_cmd_errh()
306 *
307 * Purpose: Initialize cmd fields related to error handling.
308 *
309 * Arguments: cmd - command that is ready to be queued.
310 *
311 * Notes: This function has the job of initializing a number of
312 * fields related to error handling. Typically this will
313 * be called once for each command, as required.
314 */
315static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
316{
317 scsi_set_resid(cmd, 0);
318 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
319 if (cmd->cmd_len == 0)
320 cmd->cmd_len = scsi_command_size(cmd->cmnd);
321}
322
323/*
324 * Decrement the host_busy counter and wake up the error handler if necessary.
325 * Avoid as follows that the error handler is not woken up if shost->host_busy
326 * == shost->host_failed: use call_rcu() in scsi_eh_scmd_add() in combination
327 * with an RCU read lock in this function to ensure that this function in its
328 * entirety either finishes before scsi_eh_scmd_add() increases the
329 * host_failed counter or that it notices the shost state change made by
330 * scsi_eh_scmd_add().
331 */
332static void scsi_dec_host_busy(struct Scsi_Host *shost)
333{
334 unsigned long flags;
335
336 rcu_read_lock();
337 atomic_dec(&shost->host_busy);
338 if (unlikely(scsi_host_in_recovery(shost))) {
339 spin_lock_irqsave(shost->host_lock, flags);
340 if (shost->host_failed || shost->host_eh_scheduled)
341 scsi_eh_wakeup(shost);
342 spin_unlock_irqrestore(shost->host_lock, flags);
343 }
344 rcu_read_unlock();
345}
346
347void scsi_device_unbusy(struct scsi_device *sdev)
348{
349 struct Scsi_Host *shost = sdev->host;
350 struct scsi_target *starget = scsi_target(sdev);
351
352 scsi_dec_host_busy(shost);
353
354 if (starget->can_queue > 0)
355 atomic_dec(&starget->target_busy);
356
357 atomic_dec(&sdev->device_busy);
358}
359
360static void scsi_kick_queue(struct request_queue *q)
361{
362 blk_mq_run_hw_queues(q, false);
363}
364
365/*
366 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
367 * and call blk_run_queue for all the scsi_devices on the target -
368 * including current_sdev first.
369 *
370 * Called with *no* scsi locks held.
371 */
372static void scsi_single_lun_run(struct scsi_device *current_sdev)
373{
374 struct Scsi_Host *shost = current_sdev->host;
375 struct scsi_device *sdev, *tmp;
376 struct scsi_target *starget = scsi_target(current_sdev);
377 unsigned long flags;
378
379 spin_lock_irqsave(shost->host_lock, flags);
380 starget->starget_sdev_user = NULL;
381 spin_unlock_irqrestore(shost->host_lock, flags);
382
383 /*
384 * Call blk_run_queue for all LUNs on the target, starting with
385 * current_sdev. We race with others (to set starget_sdev_user),
386 * but in most cases, we will be first. Ideally, each LU on the
387 * target would get some limited time or requests on the target.
388 */
389 scsi_kick_queue(current_sdev->request_queue);
390
391 spin_lock_irqsave(shost->host_lock, flags);
392 if (starget->starget_sdev_user)
393 goto out;
394 list_for_each_entry_safe(sdev, tmp, &starget->devices,
395 same_target_siblings) {
396 if (sdev == current_sdev)
397 continue;
398 if (scsi_device_get(sdev))
399 continue;
400
401 spin_unlock_irqrestore(shost->host_lock, flags);
402 scsi_kick_queue(sdev->request_queue);
403 spin_lock_irqsave(shost->host_lock, flags);
404
405 scsi_device_put(sdev);
406 }
407 out:
408 spin_unlock_irqrestore(shost->host_lock, flags);
409}
410
411static inline bool scsi_device_is_busy(struct scsi_device *sdev)
412{
413 if (atomic_read(&sdev->device_busy) >= sdev->queue_depth)
414 return true;
415 if (atomic_read(&sdev->device_blocked) > 0)
416 return true;
417 return false;
418}
419
420static inline bool scsi_target_is_busy(struct scsi_target *starget)
421{
422 if (starget->can_queue > 0) {
423 if (atomic_read(&starget->target_busy) >= starget->can_queue)
424 return true;
425 if (atomic_read(&starget->target_blocked) > 0)
426 return true;
427 }
428 return false;
429}
430
431static inline bool scsi_host_is_busy(struct Scsi_Host *shost)
432{
433 if (shost->can_queue > 0 &&
434 atomic_read(&shost->host_busy) >= shost->can_queue)
435 return true;
436 if (atomic_read(&shost->host_blocked) > 0)
437 return true;
438 if (shost->host_self_blocked)
439 return true;
440 return false;
441}
442
443static void scsi_starved_list_run(struct Scsi_Host *shost)
444{
445 LIST_HEAD(starved_list);
446 struct scsi_device *sdev;
447 unsigned long flags;
448
449 spin_lock_irqsave(shost->host_lock, flags);
450 list_splice_init(&shost->starved_list, &starved_list);
451
452 while (!list_empty(&starved_list)) {
453 struct request_queue *slq;
454
455 /*
456 * As long as shost is accepting commands and we have
457 * starved queues, call blk_run_queue. scsi_request_fn
458 * drops the queue_lock and can add us back to the
459 * starved_list.
460 *
461 * host_lock protects the starved_list and starved_entry.
462 * scsi_request_fn must get the host_lock before checking
463 * or modifying starved_list or starved_entry.
464 */
465 if (scsi_host_is_busy(shost))
466 break;
467
468 sdev = list_entry(starved_list.next,
469 struct scsi_device, starved_entry);
470 list_del_init(&sdev->starved_entry);
471 if (scsi_target_is_busy(scsi_target(sdev))) {
472 list_move_tail(&sdev->starved_entry,
473 &shost->starved_list);
474 continue;
475 }
476
477 /*
478 * Once we drop the host lock, a racing scsi_remove_device()
479 * call may remove the sdev from the starved list and destroy
480 * it and the queue. Mitigate by taking a reference to the
481 * queue and never touching the sdev again after we drop the
482 * host lock. Note: if __scsi_remove_device() invokes
483 * blk_cleanup_queue() before the queue is run from this
484 * function then blk_run_queue() will return immediately since
485 * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING.
486 */
487 slq = sdev->request_queue;
488 if (!blk_get_queue(slq))
489 continue;
490 spin_unlock_irqrestore(shost->host_lock, flags);
491
492 scsi_kick_queue(slq);
493 blk_put_queue(slq);
494
495 spin_lock_irqsave(shost->host_lock, flags);
496 }
497 /* put any unprocessed entries back */
498 list_splice(&starved_list, &shost->starved_list);
499 spin_unlock_irqrestore(shost->host_lock, flags);
500}
501
502/*
503 * Function: scsi_run_queue()
504 *
505 * Purpose: Select a proper request queue to serve next
506 *
507 * Arguments: q - last request's queue
508 *
509 * Returns: Nothing
510 *
511 * Notes: The previous command was completely finished, start
512 * a new one if possible.
513 */
514static void scsi_run_queue(struct request_queue *q)
515{
516 struct scsi_device *sdev = q->queuedata;
517
518 if (scsi_target(sdev)->single_lun)
519 scsi_single_lun_run(sdev);
520 if (!list_empty(&sdev->host->starved_list))
521 scsi_starved_list_run(sdev->host);
522
523 blk_mq_run_hw_queues(q, false);
524}
525
526void scsi_requeue_run_queue(struct work_struct *work)
527{
528 struct scsi_device *sdev;
529 struct request_queue *q;
530
531 sdev = container_of(work, struct scsi_device, requeue_work);
532 q = sdev->request_queue;
533 scsi_run_queue(q);
534}
535
536void scsi_run_host_queues(struct Scsi_Host *shost)
537{
538 struct scsi_device *sdev;
539
540 shost_for_each_device(sdev, shost)
541 scsi_run_queue(sdev->request_queue);
542}
543
544static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
545{
546 if (!blk_rq_is_passthrough(cmd->request)) {
547 struct scsi_driver *drv = scsi_cmd_to_driver(cmd);
548
549 if (drv->uninit_command)
550 drv->uninit_command(cmd);
551 }
552}
553
554static void scsi_mq_free_sgtables(struct scsi_cmnd *cmd)
555{
556 if (cmd->sdb.table.nents)
557 sg_free_table_chained(&cmd->sdb.table,
558 SCSI_INLINE_SG_CNT);
559 if (scsi_prot_sg_count(cmd))
560 sg_free_table_chained(&cmd->prot_sdb->table,
561 SCSI_INLINE_PROT_SG_CNT);
562}
563
564static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
565{
566 scsi_mq_free_sgtables(cmd);
567 scsi_uninit_cmd(cmd);
568 scsi_del_cmd_from_list(cmd);
569}
570
571/* Returns false when no more bytes to process, true if there are more */
572static bool scsi_end_request(struct request *req, blk_status_t error,
573 unsigned int bytes)
574{
575 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
576 struct scsi_device *sdev = cmd->device;
577 struct request_queue *q = sdev->request_queue;
578
579 if (blk_update_request(req, error, bytes))
580 return true;
581
582 if (blk_queue_add_random(q))
583 add_disk_randomness(req->rq_disk);
584
585 if (!blk_rq_is_scsi(req)) {
586 WARN_ON_ONCE(!(cmd->flags & SCMD_INITIALIZED));
587 cmd->flags &= ~SCMD_INITIALIZED;
588 }
589
590 /*
591 * Calling rcu_barrier() is not necessary here because the
592 * SCSI error handler guarantees that the function called by
593 * call_rcu() has been called before scsi_end_request() is
594 * called.
595 */
596 destroy_rcu_head(&cmd->rcu);
597
598 /*
599 * In the MQ case the command gets freed by __blk_mq_end_request,
600 * so we have to do all cleanup that depends on it earlier.
601 *
602 * We also can't kick the queues from irq context, so we
603 * will have to defer it to a workqueue.
604 */
605 scsi_mq_uninit_cmd(cmd);
606
607 /*
608 * queue is still alive, so grab the ref for preventing it
609 * from being cleaned up during running queue.
610 */
611 percpu_ref_get(&q->q_usage_counter);
612
613 __blk_mq_end_request(req, error);
614
615 if (scsi_target(sdev)->single_lun ||
616 !list_empty(&sdev->host->starved_list))
617 kblockd_schedule_work(&sdev->requeue_work);
618 else
619 blk_mq_run_hw_queues(q, true);
620
621 percpu_ref_put(&q->q_usage_counter);
622 return false;
623}
624
625/**
626 * scsi_result_to_blk_status - translate a SCSI result code into blk_status_t
627 * @cmd: SCSI command
628 * @result: scsi error code
629 *
630 * Translate a SCSI result code into a blk_status_t value. May reset the host
631 * byte of @cmd->result.
632 */
633static blk_status_t scsi_result_to_blk_status(struct scsi_cmnd *cmd, int result)
634{
635 switch (host_byte(result)) {
636 case DID_OK:
637 /*
638 * Also check the other bytes than the status byte in result
639 * to handle the case when a SCSI LLD sets result to
640 * DRIVER_SENSE << 24 without setting SAM_STAT_CHECK_CONDITION.
641 */
642 if (scsi_status_is_good(result) && (result & ~0xff) == 0)
643 return BLK_STS_OK;
644 return BLK_STS_IOERR;
645 case DID_TRANSPORT_FAILFAST:
646 return BLK_STS_TRANSPORT;
647 case DID_TARGET_FAILURE:
648 set_host_byte(cmd, DID_OK);
649 return BLK_STS_TARGET;
650 case DID_NEXUS_FAILURE:
651 set_host_byte(cmd, DID_OK);
652 return BLK_STS_NEXUS;
653 case DID_ALLOC_FAILURE:
654 set_host_byte(cmd, DID_OK);
655 return BLK_STS_NOSPC;
656 case DID_MEDIUM_ERROR:
657 set_host_byte(cmd, DID_OK);
658 return BLK_STS_MEDIUM;
659 default:
660 return BLK_STS_IOERR;
661 }
662}
663
664/* Helper for scsi_io_completion() when "reprep" action required. */
665static void scsi_io_completion_reprep(struct scsi_cmnd *cmd,
666 struct request_queue *q)
667{
668 /* A new command will be prepared and issued. */
669 scsi_mq_requeue_cmd(cmd);
670}
671
672/* Helper for scsi_io_completion() when special action required. */
673static void scsi_io_completion_action(struct scsi_cmnd *cmd, int result)
674{
675 struct request_queue *q = cmd->device->request_queue;
676 struct request *req = cmd->request;
677 int level = 0;
678 enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,
679 ACTION_DELAYED_RETRY} action;
680 unsigned long wait_for = (cmd->allowed + 1) * req->timeout;
681 struct scsi_sense_hdr sshdr;
682 bool sense_valid;
683 bool sense_current = true; /* false implies "deferred sense" */
684 blk_status_t blk_stat;
685
686 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
687 if (sense_valid)
688 sense_current = !scsi_sense_is_deferred(&sshdr);
689
690 blk_stat = scsi_result_to_blk_status(cmd, result);
691
692 if (host_byte(result) == DID_RESET) {
693 /* Third party bus reset or reset for error recovery
694 * reasons. Just retry the command and see what
695 * happens.
696 */
697 action = ACTION_RETRY;
698 } else if (sense_valid && sense_current) {
699 switch (sshdr.sense_key) {
700 case UNIT_ATTENTION:
701 if (cmd->device->removable) {
702 /* Detected disc change. Set a bit
703 * and quietly refuse further access.
704 */
705 cmd->device->changed = 1;
706 action = ACTION_FAIL;
707 } else {
708 /* Must have been a power glitch, or a
709 * bus reset. Could not have been a
710 * media change, so we just retry the
711 * command and see what happens.
712 */
713 action = ACTION_RETRY;
714 }
715 break;
716 case ILLEGAL_REQUEST:
717 /* If we had an ILLEGAL REQUEST returned, then
718 * we may have performed an unsupported
719 * command. The only thing this should be
720 * would be a ten byte read where only a six
721 * byte read was supported. Also, on a system
722 * where READ CAPACITY failed, we may have
723 * read past the end of the disk.
724 */
725 if ((cmd->device->use_10_for_rw &&
726 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
727 (cmd->cmnd[0] == READ_10 ||
728 cmd->cmnd[0] == WRITE_10)) {
729 /* This will issue a new 6-byte command. */
730 cmd->device->use_10_for_rw = 0;
731 action = ACTION_REPREP;
732 } else if (sshdr.asc == 0x10) /* DIX */ {
733 action = ACTION_FAIL;
734 blk_stat = BLK_STS_PROTECTION;
735 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
736 } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
737 action = ACTION_FAIL;
738 blk_stat = BLK_STS_TARGET;
739 } else
740 action = ACTION_FAIL;
741 break;
742 case ABORTED_COMMAND:
743 action = ACTION_FAIL;
744 if (sshdr.asc == 0x10) /* DIF */
745 blk_stat = BLK_STS_PROTECTION;
746 break;
747 case NOT_READY:
748 /* If the device is in the process of becoming
749 * ready, or has a temporary blockage, retry.
750 */
751 if (sshdr.asc == 0x04) {
752 switch (sshdr.ascq) {
753 case 0x01: /* becoming ready */
754 case 0x04: /* format in progress */
755 case 0x05: /* rebuild in progress */
756 case 0x06: /* recalculation in progress */
757 case 0x07: /* operation in progress */
758 case 0x08: /* Long write in progress */
759 case 0x09: /* self test in progress */
760 case 0x14: /* space allocation in progress */
761 case 0x1a: /* start stop unit in progress */
762 case 0x1b: /* sanitize in progress */
763 case 0x1d: /* configuration in progress */
764 case 0x24: /* depopulation in progress */
765 action = ACTION_DELAYED_RETRY;
766 break;
767 default:
768 action = ACTION_FAIL;
769 break;
770 }
771 } else
772 action = ACTION_FAIL;
773 break;
774 case VOLUME_OVERFLOW:
775 /* See SSC3rXX or current. */
776 action = ACTION_FAIL;
777 break;
778 default:
779 action = ACTION_FAIL;
780 break;
781 }
782 } else
783 action = ACTION_FAIL;
784
785 if (action != ACTION_FAIL &&
786 time_before(cmd->jiffies_at_alloc + wait_for, jiffies))
787 action = ACTION_FAIL;
788
789 switch (action) {
790 case ACTION_FAIL:
791 /* Give up and fail the remainder of the request */
792 if (!(req->rq_flags & RQF_QUIET)) {
793 static DEFINE_RATELIMIT_STATE(_rs,
794 DEFAULT_RATELIMIT_INTERVAL,
795 DEFAULT_RATELIMIT_BURST);
796
797 if (unlikely(scsi_logging_level))
798 level =
799 SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
800 SCSI_LOG_MLCOMPLETE_BITS);
801
802 /*
803 * if logging is enabled the failure will be printed
804 * in scsi_log_completion(), so avoid duplicate messages
805 */
806 if (!level && __ratelimit(&_rs)) {
807 scsi_print_result(cmd, NULL, FAILED);
808 if (driver_byte(result) == DRIVER_SENSE)
809 scsi_print_sense(cmd);
810 scsi_print_command(cmd);
811 }
812 }
813 if (!scsi_end_request(req, blk_stat, blk_rq_err_bytes(req)))
814 return;
815 /*FALLTHRU*/
816 case ACTION_REPREP:
817 scsi_io_completion_reprep(cmd, q);
818 break;
819 case ACTION_RETRY:
820 /* Retry the same command immediately */
821 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, false);
822 break;
823 case ACTION_DELAYED_RETRY:
824 /* Retry the same command after a delay */
825 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, false);
826 break;
827 }
828}
829
830/*
831 * Helper for scsi_io_completion() when cmd->result is non-zero. Returns a
832 * new result that may suppress further error checking. Also modifies
833 * *blk_statp in some cases.
834 */
835static int scsi_io_completion_nz_result(struct scsi_cmnd *cmd, int result,
836 blk_status_t *blk_statp)
837{
838 bool sense_valid;
839 bool sense_current = true; /* false implies "deferred sense" */
840 struct request *req = cmd->request;
841 struct scsi_sense_hdr sshdr;
842
843 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
844 if (sense_valid)
845 sense_current = !scsi_sense_is_deferred(&sshdr);
846
847 if (blk_rq_is_passthrough(req)) {
848 if (sense_valid) {
849 /*
850 * SG_IO wants current and deferred errors
851 */
852 scsi_req(req)->sense_len =
853 min(8 + cmd->sense_buffer[7],
854 SCSI_SENSE_BUFFERSIZE);
855 }
856 if (sense_current)
857 *blk_statp = scsi_result_to_blk_status(cmd, result);
858 } else if (blk_rq_bytes(req) == 0 && sense_current) {
859 /*
860 * Flush commands do not transfers any data, and thus cannot use
861 * good_bytes != blk_rq_bytes(req) as the signal for an error.
862 * This sets *blk_statp explicitly for the problem case.
863 */
864 *blk_statp = scsi_result_to_blk_status(cmd, result);
865 }
866 /*
867 * Recovered errors need reporting, but they're always treated as
868 * success, so fiddle the result code here. For passthrough requests
869 * we already took a copy of the original into sreq->result which
870 * is what gets returned to the user
871 */
872 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
873 bool do_print = true;
874 /*
875 * if ATA PASS-THROUGH INFORMATION AVAILABLE [0x0, 0x1d]
876 * skip print since caller wants ATA registers. Only occurs
877 * on SCSI ATA PASS_THROUGH commands when CK_COND=1
878 */
879 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
880 do_print = false;
881 else if (req->rq_flags & RQF_QUIET)
882 do_print = false;
883 if (do_print)
884 scsi_print_sense(cmd);
885 result = 0;
886 /* for passthrough, *blk_statp may be set */
887 *blk_statp = BLK_STS_OK;
888 }
889 /*
890 * Another corner case: the SCSI status byte is non-zero but 'good'.
891 * Example: PRE-FETCH command returns SAM_STAT_CONDITION_MET when
892 * it is able to fit nominated LBs in its cache (and SAM_STAT_GOOD
893 * if it can't fit). Treat SAM_STAT_CONDITION_MET and the related
894 * intermediate statuses (both obsolete in SAM-4) as good.
895 */
896 if (status_byte(result) && scsi_status_is_good(result)) {
897 result = 0;
898 *blk_statp = BLK_STS_OK;
899 }
900 return result;
901}
902
903/*
904 * Function: scsi_io_completion()
905 *
906 * Purpose: Completion processing for block device I/O requests.
907 *
908 * Arguments: cmd - command that is finished.
909 *
910 * Lock status: Assumed that no lock is held upon entry.
911 *
912 * Returns: Nothing
913 *
914 * Notes: We will finish off the specified number of sectors. If we
915 * are done, the command block will be released and the queue
916 * function will be goosed. If we are not done then we have to
917 * figure out what to do next:
918 *
919 * a) We can call scsi_requeue_command(). The request
920 * will be unprepared and put back on the queue. Then
921 * a new command will be created for it. This should
922 * be used if we made forward progress, or if we want
923 * to switch from READ(10) to READ(6) for example.
924 *
925 * b) We can call __scsi_queue_insert(). The request will
926 * be put back on the queue and retried using the same
927 * command as before, possibly after a delay.
928 *
929 * c) We can call scsi_end_request() with blk_stat other than
930 * BLK_STS_OK, to fail the remainder of the request.
931 */
932void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
933{
934 int result = cmd->result;
935 struct request_queue *q = cmd->device->request_queue;
936 struct request *req = cmd->request;
937 blk_status_t blk_stat = BLK_STS_OK;
938
939 if (unlikely(result)) /* a nz result may or may not be an error */
940 result = scsi_io_completion_nz_result(cmd, result, &blk_stat);
941
942 if (unlikely(blk_rq_is_passthrough(req))) {
943 /*
944 * scsi_result_to_blk_status may have reset the host_byte
945 */
946 scsi_req(req)->result = cmd->result;
947 }
948
949 /*
950 * Next deal with any sectors which we were able to correctly
951 * handle.
952 */
953 SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd,
954 "%u sectors total, %d bytes done.\n",
955 blk_rq_sectors(req), good_bytes));
956
957 /*
958 * Next deal with any sectors which we were able to correctly
959 * handle. Failed, zero length commands always need to drop down
960 * to retry code. Fast path should return in this block.
961 */
962 if (likely(blk_rq_bytes(req) > 0 || blk_stat == BLK_STS_OK)) {
963 if (likely(!scsi_end_request(req, blk_stat, good_bytes)))
964 return; /* no bytes remaining */
965 }
966
967 /* Kill remainder if no retries. */
968 if (unlikely(blk_stat && scsi_noretry_cmd(cmd))) {
969 if (scsi_end_request(req, blk_stat, blk_rq_bytes(req)))
970 WARN_ONCE(true,
971 "Bytes remaining after failed, no-retry command");
972 return;
973 }
974
975 /*
976 * If there had been no error, but we have leftover bytes in the
977 * requeues just queue the command up again.
978 */
979 if (likely(result == 0))
980 scsi_io_completion_reprep(cmd, q);
981 else
982 scsi_io_completion_action(cmd, result);
983}
984
985static blk_status_t scsi_init_sgtable(struct request *req,
986 struct scsi_data_buffer *sdb)
987{
988 int count;
989
990 /*
991 * If sg table allocation fails, requeue request later.
992 */
993 if (unlikely(sg_alloc_table_chained(&sdb->table,
994 blk_rq_nr_phys_segments(req), sdb->table.sgl,
995 SCSI_INLINE_SG_CNT)))
996 return BLK_STS_RESOURCE;
997
998 /*
999 * Next, walk the list, and fill in the addresses and sizes of
1000 * each segment.
1001 */
1002 count = blk_rq_map_sg(req->q, req, sdb->table.sgl);
1003 BUG_ON(count > sdb->table.nents);
1004 sdb->table.nents = count;
1005 sdb->length = blk_rq_payload_bytes(req);
1006 return BLK_STS_OK;
1007}
1008
1009/*
1010 * Function: scsi_init_io()
1011 *
1012 * Purpose: SCSI I/O initialize function.
1013 *
1014 * Arguments: cmd - Command descriptor we wish to initialize
1015 *
1016 * Returns: BLK_STS_OK on success
1017 * BLK_STS_RESOURCE if the failure is retryable
1018 * BLK_STS_IOERR if the failure is fatal
1019 */
1020blk_status_t scsi_init_io(struct scsi_cmnd *cmd)
1021{
1022 struct request *rq = cmd->request;
1023 blk_status_t ret;
1024
1025 if (WARN_ON_ONCE(!blk_rq_nr_phys_segments(rq)))
1026 return BLK_STS_IOERR;
1027
1028 ret = scsi_init_sgtable(rq, &cmd->sdb);
1029 if (ret)
1030 return ret;
1031
1032 if (blk_integrity_rq(rq)) {
1033 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1034 int ivecs, count;
1035
1036 if (WARN_ON_ONCE(!prot_sdb)) {
1037 /*
1038 * This can happen if someone (e.g. multipath)
1039 * queues a command to a device on an adapter
1040 * that does not support DIX.
1041 */
1042 ret = BLK_STS_IOERR;
1043 goto out_free_sgtables;
1044 }
1045
1046 ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
1047
1048 if (sg_alloc_table_chained(&prot_sdb->table, ivecs,
1049 prot_sdb->table.sgl,
1050 SCSI_INLINE_PROT_SG_CNT)) {
1051 ret = BLK_STS_RESOURCE;
1052 goto out_free_sgtables;
1053 }
1054
1055 count = blk_rq_map_integrity_sg(rq->q, rq->bio,
1056 prot_sdb->table.sgl);
1057 BUG_ON(count > ivecs);
1058 BUG_ON(count > queue_max_integrity_segments(rq->q));
1059
1060 cmd->prot_sdb = prot_sdb;
1061 cmd->prot_sdb->table.nents = count;
1062 }
1063
1064 return BLK_STS_OK;
1065out_free_sgtables:
1066 scsi_mq_free_sgtables(cmd);
1067 return ret;
1068}
1069EXPORT_SYMBOL(scsi_init_io);
1070
1071/**
1072 * scsi_initialize_rq - initialize struct scsi_cmnd partially
1073 * @rq: Request associated with the SCSI command to be initialized.
1074 *
1075 * This function initializes the members of struct scsi_cmnd that must be
1076 * initialized before request processing starts and that won't be
1077 * reinitialized if a SCSI command is requeued.
1078 *
1079 * Called from inside blk_get_request() for pass-through requests and from
1080 * inside scsi_init_command() for filesystem requests.
1081 */
1082static void scsi_initialize_rq(struct request *rq)
1083{
1084 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1085
1086 scsi_req_init(&cmd->req);
1087 init_rcu_head(&cmd->rcu);
1088 cmd->jiffies_at_alloc = jiffies;
1089 cmd->retries = 0;
1090}
1091
1092/*
1093 * Only called when the request isn't completed by SCSI, and not freed by
1094 * SCSI
1095 */
1096static void scsi_cleanup_rq(struct request *rq)
1097{
1098 if (rq->rq_flags & RQF_DONTPREP) {
1099 scsi_mq_uninit_cmd(blk_mq_rq_to_pdu(rq));
1100 rq->rq_flags &= ~RQF_DONTPREP;
1101 }
1102}
1103
1104/* Add a command to the list used by the aacraid and dpt_i2o drivers */
1105void scsi_add_cmd_to_list(struct scsi_cmnd *cmd)
1106{
1107 struct scsi_device *sdev = cmd->device;
1108 struct Scsi_Host *shost = sdev->host;
1109 unsigned long flags;
1110
1111 if (shost->use_cmd_list) {
1112 spin_lock_irqsave(&sdev->list_lock, flags);
1113 list_add_tail(&cmd->list, &sdev->cmd_list);
1114 spin_unlock_irqrestore(&sdev->list_lock, flags);
1115 }
1116}
1117
1118/* Remove a command from the list used by the aacraid and dpt_i2o drivers */
1119void scsi_del_cmd_from_list(struct scsi_cmnd *cmd)
1120{
1121 struct scsi_device *sdev = cmd->device;
1122 struct Scsi_Host *shost = sdev->host;
1123 unsigned long flags;
1124
1125 if (shost->use_cmd_list) {
1126 spin_lock_irqsave(&sdev->list_lock, flags);
1127 BUG_ON(list_empty(&cmd->list));
1128 list_del_init(&cmd->list);
1129 spin_unlock_irqrestore(&sdev->list_lock, flags);
1130 }
1131}
1132
1133/* Called after a request has been started. */
1134void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd)
1135{
1136 void *buf = cmd->sense_buffer;
1137 void *prot = cmd->prot_sdb;
1138 struct request *rq = blk_mq_rq_from_pdu(cmd);
1139 unsigned int flags = cmd->flags & SCMD_PRESERVED_FLAGS;
1140 unsigned long jiffies_at_alloc;
1141 int retries;
1142
1143 if (!blk_rq_is_scsi(rq) && !(flags & SCMD_INITIALIZED)) {
1144 flags |= SCMD_INITIALIZED;
1145 scsi_initialize_rq(rq);
1146 }
1147
1148 jiffies_at_alloc = cmd->jiffies_at_alloc;
1149 retries = cmd->retries;
1150 /* zero out the cmd, except for the embedded scsi_request */
1151 memset((char *)cmd + sizeof(cmd->req), 0,
1152 sizeof(*cmd) - sizeof(cmd->req) + dev->host->hostt->cmd_size);
1153
1154 cmd->device = dev;
1155 cmd->sense_buffer = buf;
1156 cmd->prot_sdb = prot;
1157 cmd->flags = flags;
1158 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
1159 cmd->jiffies_at_alloc = jiffies_at_alloc;
1160 cmd->retries = retries;
1161
1162 scsi_add_cmd_to_list(cmd);
1163}
1164
1165static blk_status_t scsi_setup_scsi_cmnd(struct scsi_device *sdev,
1166 struct request *req)
1167{
1168 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1169
1170 /*
1171 * Passthrough requests may transfer data, in which case they must
1172 * a bio attached to them. Or they might contain a SCSI command
1173 * that does not transfer data, in which case they may optionally
1174 * submit a request without an attached bio.
1175 */
1176 if (req->bio) {
1177 blk_status_t ret = scsi_init_io(cmd);
1178 if (unlikely(ret != BLK_STS_OK))
1179 return ret;
1180 } else {
1181 BUG_ON(blk_rq_bytes(req));
1182
1183 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1184 }
1185
1186 cmd->cmd_len = scsi_req(req)->cmd_len;
1187 cmd->cmnd = scsi_req(req)->cmd;
1188 cmd->transfersize = blk_rq_bytes(req);
1189 cmd->allowed = scsi_req(req)->retries;
1190 return BLK_STS_OK;
1191}
1192
1193/*
1194 * Setup a normal block command. These are simple request from filesystems
1195 * that still need to be translated to SCSI CDBs from the ULD.
1196 */
1197static blk_status_t scsi_setup_fs_cmnd(struct scsi_device *sdev,
1198 struct request *req)
1199{
1200 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1201
1202 if (unlikely(sdev->handler && sdev->handler->prep_fn)) {
1203 blk_status_t ret = sdev->handler->prep_fn(sdev, req);
1204 if (ret != BLK_STS_OK)
1205 return ret;
1206 }
1207
1208 cmd->cmnd = scsi_req(req)->cmd = scsi_req(req)->__cmd;
1209 memset(cmd->cmnd, 0, BLK_MAX_CDB);
1210 return scsi_cmd_to_driver(cmd)->init_command(cmd);
1211}
1212
1213static blk_status_t scsi_setup_cmnd(struct scsi_device *sdev,
1214 struct request *req)
1215{
1216 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1217
1218 if (!blk_rq_bytes(req))
1219 cmd->sc_data_direction = DMA_NONE;
1220 else if (rq_data_dir(req) == WRITE)
1221 cmd->sc_data_direction = DMA_TO_DEVICE;
1222 else
1223 cmd->sc_data_direction = DMA_FROM_DEVICE;
1224
1225 if (blk_rq_is_scsi(req))
1226 return scsi_setup_scsi_cmnd(sdev, req);
1227 else
1228 return scsi_setup_fs_cmnd(sdev, req);
1229}
1230
1231static blk_status_t
1232scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
1233{
1234 switch (sdev->sdev_state) {
1235 case SDEV_OFFLINE:
1236 case SDEV_TRANSPORT_OFFLINE:
1237 /*
1238 * If the device is offline we refuse to process any
1239 * commands. The device must be brought online
1240 * before trying any recovery commands.
1241 */
1242 sdev_printk(KERN_ERR, sdev,
1243 "rejecting I/O to offline device\n");
1244 return BLK_STS_IOERR;
1245 case SDEV_DEL:
1246 /*
1247 * If the device is fully deleted, we refuse to
1248 * process any commands as well.
1249 */
1250 sdev_printk(KERN_ERR, sdev,
1251 "rejecting I/O to dead device\n");
1252 return BLK_STS_IOERR;
1253 case SDEV_BLOCK:
1254 case SDEV_CREATED_BLOCK:
1255 return BLK_STS_RESOURCE;
1256 case SDEV_QUIESCE:
1257 /*
1258 * If the devices is blocked we defer normal commands.
1259 */
1260 if (req && !(req->rq_flags & RQF_PREEMPT))
1261 return BLK_STS_RESOURCE;
1262 return BLK_STS_OK;
1263 default:
1264 /*
1265 * For any other not fully online state we only allow
1266 * special commands. In particular any user initiated
1267 * command is not allowed.
1268 */
1269 if (req && !(req->rq_flags & RQF_PREEMPT))
1270 return BLK_STS_IOERR;
1271 return BLK_STS_OK;
1272 }
1273}
1274
1275/*
1276 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1277 * return 0.
1278 *
1279 * Called with the queue_lock held.
1280 */
1281static inline int scsi_dev_queue_ready(struct request_queue *q,
1282 struct scsi_device *sdev)
1283{
1284 unsigned int busy;
1285
1286 busy = atomic_inc_return(&sdev->device_busy) - 1;
1287 if (atomic_read(&sdev->device_blocked)) {
1288 if (busy)
1289 goto out_dec;
1290
1291 /*
1292 * unblock after device_blocked iterates to zero
1293 */
1294 if (atomic_dec_return(&sdev->device_blocked) > 0)
1295 goto out_dec;
1296 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev,
1297 "unblocking device at zero depth\n"));
1298 }
1299
1300 if (busy >= sdev->queue_depth)
1301 goto out_dec;
1302
1303 return 1;
1304out_dec:
1305 atomic_dec(&sdev->device_busy);
1306 return 0;
1307}
1308
1309/*
1310 * scsi_target_queue_ready: checks if there we can send commands to target
1311 * @sdev: scsi device on starget to check.
1312 */
1313static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1314 struct scsi_device *sdev)
1315{
1316 struct scsi_target *starget = scsi_target(sdev);
1317 unsigned int busy;
1318
1319 if (starget->single_lun) {
1320 spin_lock_irq(shost->host_lock);
1321 if (starget->starget_sdev_user &&
1322 starget->starget_sdev_user != sdev) {
1323 spin_unlock_irq(shost->host_lock);
1324 return 0;
1325 }
1326 starget->starget_sdev_user = sdev;
1327 spin_unlock_irq(shost->host_lock);
1328 }
1329
1330 if (starget->can_queue <= 0)
1331 return 1;
1332
1333 busy = atomic_inc_return(&starget->target_busy) - 1;
1334 if (atomic_read(&starget->target_blocked) > 0) {
1335 if (busy)
1336 goto starved;
1337
1338 /*
1339 * unblock after target_blocked iterates to zero
1340 */
1341 if (atomic_dec_return(&starget->target_blocked) > 0)
1342 goto out_dec;
1343
1344 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1345 "unblocking target at zero depth\n"));
1346 }
1347
1348 if (busy >= starget->can_queue)
1349 goto starved;
1350
1351 return 1;
1352
1353starved:
1354 spin_lock_irq(shost->host_lock);
1355 list_move_tail(&sdev->starved_entry, &shost->starved_list);
1356 spin_unlock_irq(shost->host_lock);
1357out_dec:
1358 if (starget->can_queue > 0)
1359 atomic_dec(&starget->target_busy);
1360 return 0;
1361}
1362
1363/*
1364 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1365 * return 0. We must end up running the queue again whenever 0 is
1366 * returned, else IO can hang.
1367 */
1368static inline int scsi_host_queue_ready(struct request_queue *q,
1369 struct Scsi_Host *shost,
1370 struct scsi_device *sdev)
1371{
1372 unsigned int busy;
1373
1374 if (scsi_host_in_recovery(shost))
1375 return 0;
1376
1377 busy = atomic_inc_return(&shost->host_busy) - 1;
1378 if (atomic_read(&shost->host_blocked) > 0) {
1379 if (busy)
1380 goto starved;
1381
1382 /*
1383 * unblock after host_blocked iterates to zero
1384 */
1385 if (atomic_dec_return(&shost->host_blocked) > 0)
1386 goto out_dec;
1387
1388 SCSI_LOG_MLQUEUE(3,
1389 shost_printk(KERN_INFO, shost,
1390 "unblocking host at zero depth\n"));
1391 }
1392
1393 if (shost->can_queue > 0 && busy >= shost->can_queue)
1394 goto starved;
1395 if (shost->host_self_blocked)
1396 goto starved;
1397
1398 /* We're OK to process the command, so we can't be starved */
1399 if (!list_empty(&sdev->starved_entry)) {
1400 spin_lock_irq(shost->host_lock);
1401 if (!list_empty(&sdev->starved_entry))
1402 list_del_init(&sdev->starved_entry);
1403 spin_unlock_irq(shost->host_lock);
1404 }
1405
1406 return 1;
1407
1408starved:
1409 spin_lock_irq(shost->host_lock);
1410 if (list_empty(&sdev->starved_entry))
1411 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1412 spin_unlock_irq(shost->host_lock);
1413out_dec:
1414 scsi_dec_host_busy(shost);
1415 return 0;
1416}
1417
1418/*
1419 * Busy state exporting function for request stacking drivers.
1420 *
1421 * For efficiency, no lock is taken to check the busy state of
1422 * shost/starget/sdev, since the returned value is not guaranteed and
1423 * may be changed after request stacking drivers call the function,
1424 * regardless of taking lock or not.
1425 *
1426 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1427 * needs to return 'not busy'. Otherwise, request stacking drivers
1428 * may hold requests forever.
1429 */
1430static bool scsi_mq_lld_busy(struct request_queue *q)
1431{
1432 struct scsi_device *sdev = q->queuedata;
1433 struct Scsi_Host *shost;
1434
1435 if (blk_queue_dying(q))
1436 return false;
1437
1438 shost = sdev->host;
1439
1440 /*
1441 * Ignore host/starget busy state.
1442 * Since block layer does not have a concept of fairness across
1443 * multiple queues, congestion of host/starget needs to be handled
1444 * in SCSI layer.
1445 */
1446 if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
1447 return true;
1448
1449 return false;
1450}
1451
1452static void scsi_softirq_done(struct request *rq)
1453{
1454 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1455 unsigned long wait_for = (cmd->allowed + 1) * rq->timeout;
1456 int disposition;
1457
1458 INIT_LIST_HEAD(&cmd->eh_entry);
1459
1460 atomic_inc(&cmd->device->iodone_cnt);
1461 if (cmd->result)
1462 atomic_inc(&cmd->device->ioerr_cnt);
1463
1464 disposition = scsi_decide_disposition(cmd);
1465 if (disposition != SUCCESS &&
1466 time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
1467 scmd_printk(KERN_ERR, cmd,
1468 "timing out command, waited %lus\n",
1469 wait_for/HZ);
1470 disposition = SUCCESS;
1471 }
1472
1473 scsi_log_completion(cmd, disposition);
1474
1475 switch (disposition) {
1476 case SUCCESS:
1477 scsi_finish_command(cmd);
1478 break;
1479 case NEEDS_RETRY:
1480 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
1481 break;
1482 case ADD_TO_MLQUEUE:
1483 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1484 break;
1485 default:
1486 scsi_eh_scmd_add(cmd);
1487 break;
1488 }
1489}
1490
1491/**
1492 * scsi_dispatch_command - Dispatch a command to the low-level driver.
1493 * @cmd: command block we are dispatching.
1494 *
1495 * Return: nonzero return request was rejected and device's queue needs to be
1496 * plugged.
1497 */
1498static int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
1499{
1500 struct Scsi_Host *host = cmd->device->host;
1501 int rtn = 0;
1502
1503 atomic_inc(&cmd->device->iorequest_cnt);
1504
1505 /* check if the device is still usable */
1506 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
1507 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
1508 * returns an immediate error upwards, and signals
1509 * that the device is no longer present */
1510 cmd->result = DID_NO_CONNECT << 16;
1511 goto done;
1512 }
1513
1514 /* Check to see if the scsi lld made this device blocked. */
1515 if (unlikely(scsi_device_blocked(cmd->device))) {
1516 /*
1517 * in blocked state, the command is just put back on
1518 * the device queue. The suspend state has already
1519 * blocked the queue so future requests should not
1520 * occur until the device transitions out of the
1521 * suspend state.
1522 */
1523 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1524 "queuecommand : device blocked\n"));
1525 return SCSI_MLQUEUE_DEVICE_BUSY;
1526 }
1527
1528 /* Store the LUN value in cmnd, if needed. */
1529 if (cmd->device->lun_in_cdb)
1530 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
1531 (cmd->device->lun << 5 & 0xe0);
1532
1533 scsi_log_send(cmd);
1534
1535 /*
1536 * Before we queue this command, check if the command
1537 * length exceeds what the host adapter can handle.
1538 */
1539 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
1540 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1541 "queuecommand : command too long. "
1542 "cdb_size=%d host->max_cmd_len=%d\n",
1543 cmd->cmd_len, cmd->device->host->max_cmd_len));
1544 cmd->result = (DID_ABORT << 16);
1545 goto done;
1546 }
1547
1548 if (unlikely(host->shost_state == SHOST_DEL)) {
1549 cmd->result = (DID_NO_CONNECT << 16);
1550 goto done;
1551
1552 }
1553
1554 trace_scsi_dispatch_cmd_start(cmd);
1555 rtn = host->hostt->queuecommand(host, cmd);
1556 if (rtn) {
1557 trace_scsi_dispatch_cmd_error(cmd, rtn);
1558 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
1559 rtn != SCSI_MLQUEUE_TARGET_BUSY)
1560 rtn = SCSI_MLQUEUE_HOST_BUSY;
1561
1562 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1563 "queuecommand : request rejected\n"));
1564 }
1565
1566 return rtn;
1567 done:
1568 cmd->scsi_done(cmd);
1569 return 0;
1570}
1571
1572/* Size in bytes of the sg-list stored in the scsi-mq command-private data. */
1573static unsigned int scsi_mq_inline_sgl_size(struct Scsi_Host *shost)
1574{
1575 return min_t(unsigned int, shost->sg_tablesize, SCSI_INLINE_SG_CNT) *
1576 sizeof(struct scatterlist);
1577}
1578
1579static blk_status_t scsi_mq_prep_fn(struct request *req)
1580{
1581 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1582 struct scsi_device *sdev = req->q->queuedata;
1583 struct Scsi_Host *shost = sdev->host;
1584 struct scatterlist *sg;
1585
1586 scsi_init_command(sdev, cmd);
1587
1588 cmd->request = req;
1589 cmd->tag = req->tag;
1590 cmd->prot_op = SCSI_PROT_NORMAL;
1591
1592 sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
1593 cmd->sdb.table.sgl = sg;
1594
1595 if (scsi_host_get_prot(shost)) {
1596 memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer));
1597
1598 cmd->prot_sdb->table.sgl =
1599 (struct scatterlist *)(cmd->prot_sdb + 1);
1600 }
1601
1602 blk_mq_start_request(req);
1603
1604 return scsi_setup_cmnd(sdev, req);
1605}
1606
1607static void scsi_mq_done(struct scsi_cmnd *cmd)
1608{
1609 if (unlikely(test_and_set_bit(SCMD_STATE_COMPLETE, &cmd->state)))
1610 return;
1611 trace_scsi_dispatch_cmd_done(cmd);
1612
1613 /*
1614 * If the block layer didn't complete the request due to a timeout
1615 * injection, scsi must clear its internal completed state so that the
1616 * timeout handler will see it needs to escalate its own error
1617 * recovery.
1618 */
1619 if (unlikely(!blk_mq_complete_request(cmd->request)))
1620 clear_bit(SCMD_STATE_COMPLETE, &cmd->state);
1621}
1622
1623static void scsi_mq_put_budget(struct blk_mq_hw_ctx *hctx)
1624{
1625 struct request_queue *q = hctx->queue;
1626 struct scsi_device *sdev = q->queuedata;
1627
1628 atomic_dec(&sdev->device_busy);
1629}
1630
1631static bool scsi_mq_get_budget(struct blk_mq_hw_ctx *hctx)
1632{
1633 struct request_queue *q = hctx->queue;
1634 struct scsi_device *sdev = q->queuedata;
1635
1636 if (scsi_dev_queue_ready(q, sdev))
1637 return true;
1638
1639 if (atomic_read(&sdev->device_busy) == 0 && !scsi_device_blocked(sdev))
1640 blk_mq_delay_run_hw_queue(hctx, SCSI_QUEUE_DELAY);
1641 return false;
1642}
1643
1644static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
1645 const struct blk_mq_queue_data *bd)
1646{
1647 struct request *req = bd->rq;
1648 struct request_queue *q = req->q;
1649 struct scsi_device *sdev = q->queuedata;
1650 struct Scsi_Host *shost = sdev->host;
1651 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1652 blk_status_t ret;
1653 int reason;
1654
1655 /*
1656 * If the device is not in running state we will reject some or all
1657 * commands.
1658 */
1659 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
1660 ret = scsi_prep_state_check(sdev, req);
1661 if (ret != BLK_STS_OK)
1662 goto out_put_budget;
1663 }
1664
1665 ret = BLK_STS_RESOURCE;
1666 if (!scsi_target_queue_ready(shost, sdev))
1667 goto out_put_budget;
1668 if (!scsi_host_queue_ready(q, shost, sdev))
1669 goto out_dec_target_busy;
1670
1671 if (!(req->rq_flags & RQF_DONTPREP)) {
1672 ret = scsi_mq_prep_fn(req);
1673 if (ret != BLK_STS_OK)
1674 goto out_dec_host_busy;
1675 req->rq_flags |= RQF_DONTPREP;
1676 } else {
1677 clear_bit(SCMD_STATE_COMPLETE, &cmd->state);
1678 blk_mq_start_request(req);
1679 }
1680
1681 cmd->flags &= SCMD_PRESERVED_FLAGS;
1682 if (sdev->simple_tags)
1683 cmd->flags |= SCMD_TAGGED;
1684 if (bd->last)
1685 cmd->flags |= SCMD_LAST;
1686
1687 scsi_init_cmd_errh(cmd);
1688 cmd->scsi_done = scsi_mq_done;
1689
1690 reason = scsi_dispatch_cmd(cmd);
1691 if (reason) {
1692 scsi_set_blocked(cmd, reason);
1693 ret = BLK_STS_RESOURCE;
1694 goto out_dec_host_busy;
1695 }
1696
1697 return BLK_STS_OK;
1698
1699out_dec_host_busy:
1700 scsi_dec_host_busy(shost);
1701out_dec_target_busy:
1702 if (scsi_target(sdev)->can_queue > 0)
1703 atomic_dec(&scsi_target(sdev)->target_busy);
1704out_put_budget:
1705 scsi_mq_put_budget(hctx);
1706 switch (ret) {
1707 case BLK_STS_OK:
1708 break;
1709 case BLK_STS_RESOURCE:
1710 if (atomic_read(&sdev->device_busy) ||
1711 scsi_device_blocked(sdev))
1712 ret = BLK_STS_DEV_RESOURCE;
1713 break;
1714 default:
1715 if (unlikely(!scsi_device_online(sdev)))
1716 scsi_req(req)->result = DID_NO_CONNECT << 16;
1717 else
1718 scsi_req(req)->result = DID_ERROR << 16;
1719 /*
1720 * Make sure to release all allocated resources when
1721 * we hit an error, as we will never see this command
1722 * again.
1723 */
1724 if (req->rq_flags & RQF_DONTPREP)
1725 scsi_mq_uninit_cmd(cmd);
1726 break;
1727 }
1728 return ret;
1729}
1730
1731static enum blk_eh_timer_return scsi_timeout(struct request *req,
1732 bool reserved)
1733{
1734 if (reserved)
1735 return BLK_EH_RESET_TIMER;
1736 return scsi_times_out(req);
1737}
1738
1739static int scsi_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
1740 unsigned int hctx_idx, unsigned int numa_node)
1741{
1742 struct Scsi_Host *shost = set->driver_data;
1743 const bool unchecked_isa_dma = shost->unchecked_isa_dma;
1744 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1745 struct scatterlist *sg;
1746
1747 if (unchecked_isa_dma)
1748 cmd->flags |= SCMD_UNCHECKED_ISA_DMA;
1749 cmd->sense_buffer = scsi_alloc_sense_buffer(unchecked_isa_dma,
1750 GFP_KERNEL, numa_node);
1751 if (!cmd->sense_buffer)
1752 return -ENOMEM;
1753 cmd->req.sense = cmd->sense_buffer;
1754
1755 if (scsi_host_get_prot(shost)) {
1756 sg = (void *)cmd + sizeof(struct scsi_cmnd) +
1757 shost->hostt->cmd_size;
1758 cmd->prot_sdb = (void *)sg + scsi_mq_inline_sgl_size(shost);
1759 }
1760
1761 return 0;
1762}
1763
1764static void scsi_mq_exit_request(struct blk_mq_tag_set *set, struct request *rq,
1765 unsigned int hctx_idx)
1766{
1767 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1768
1769 scsi_free_sense_buffer(cmd->flags & SCMD_UNCHECKED_ISA_DMA,
1770 cmd->sense_buffer);
1771}
1772
1773static int scsi_map_queues(struct blk_mq_tag_set *set)
1774{
1775 struct Scsi_Host *shost = container_of(set, struct Scsi_Host, tag_set);
1776
1777 if (shost->hostt->map_queues)
1778 return shost->hostt->map_queues(shost);
1779 return blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]);
1780}
1781
1782void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
1783{
1784 struct device *dev = shost->dma_dev;
1785
1786 /*
1787 * this limit is imposed by hardware restrictions
1788 */
1789 blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
1790 SG_MAX_SEGMENTS));
1791
1792 if (scsi_host_prot_dma(shost)) {
1793 shost->sg_prot_tablesize =
1794 min_not_zero(shost->sg_prot_tablesize,
1795 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
1796 BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
1797 blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
1798 }
1799
1800 if (dev->dma_mask) {
1801 shost->max_sectors = min_t(unsigned int, shost->max_sectors,
1802 dma_max_mapping_size(dev) >> SECTOR_SHIFT);
1803 }
1804 blk_queue_max_hw_sectors(q, shost->max_sectors);
1805 if (shost->unchecked_isa_dma)
1806 blk_queue_bounce_limit(q, BLK_BOUNCE_ISA);
1807 blk_queue_segment_boundary(q, shost->dma_boundary);
1808 dma_set_seg_boundary(dev, shost->dma_boundary);
1809
1810 blk_queue_max_segment_size(q, shost->max_segment_size);
1811 blk_queue_virt_boundary(q, shost->virt_boundary_mask);
1812 dma_set_max_seg_size(dev, queue_max_segment_size(q));
1813
1814 /*
1815 * Set a reasonable default alignment: The larger of 32-byte (dword),
1816 * which is a common minimum for HBAs, and the minimum DMA alignment,
1817 * which is set by the platform.
1818 *
1819 * Devices that require a bigger alignment can increase it later.
1820 */
1821 blk_queue_dma_alignment(q, max(4, dma_get_cache_alignment()) - 1);
1822}
1823EXPORT_SYMBOL_GPL(__scsi_init_queue);
1824
1825static const struct blk_mq_ops scsi_mq_ops_no_commit = {
1826 .get_budget = scsi_mq_get_budget,
1827 .put_budget = scsi_mq_put_budget,
1828 .queue_rq = scsi_queue_rq,
1829 .complete = scsi_softirq_done,
1830 .timeout = scsi_timeout,
1831#ifdef CONFIG_BLK_DEBUG_FS
1832 .show_rq = scsi_show_rq,
1833#endif
1834 .init_request = scsi_mq_init_request,
1835 .exit_request = scsi_mq_exit_request,
1836 .initialize_rq_fn = scsi_initialize_rq,
1837 .cleanup_rq = scsi_cleanup_rq,
1838 .busy = scsi_mq_lld_busy,
1839 .map_queues = scsi_map_queues,
1840};
1841
1842
1843static void scsi_commit_rqs(struct blk_mq_hw_ctx *hctx)
1844{
1845 struct request_queue *q = hctx->queue;
1846 struct scsi_device *sdev = q->queuedata;
1847 struct Scsi_Host *shost = sdev->host;
1848
1849 shost->hostt->commit_rqs(shost, hctx->queue_num);
1850}
1851
1852static const struct blk_mq_ops scsi_mq_ops = {
1853 .get_budget = scsi_mq_get_budget,
1854 .put_budget = scsi_mq_put_budget,
1855 .queue_rq = scsi_queue_rq,
1856 .commit_rqs = scsi_commit_rqs,
1857 .complete = scsi_softirq_done,
1858 .timeout = scsi_timeout,
1859#ifdef CONFIG_BLK_DEBUG_FS
1860 .show_rq = scsi_show_rq,
1861#endif
1862 .init_request = scsi_mq_init_request,
1863 .exit_request = scsi_mq_exit_request,
1864 .initialize_rq_fn = scsi_initialize_rq,
1865 .cleanup_rq = scsi_cleanup_rq,
1866 .busy = scsi_mq_lld_busy,
1867 .map_queues = scsi_map_queues,
1868};
1869
1870struct request_queue *scsi_mq_alloc_queue(struct scsi_device *sdev)
1871{
1872 sdev->request_queue = blk_mq_init_queue(&sdev->host->tag_set);
1873 if (IS_ERR(sdev->request_queue))
1874 return NULL;
1875
1876 sdev->request_queue->queuedata = sdev;
1877 __scsi_init_queue(sdev->host, sdev->request_queue);
1878 blk_queue_flag_set(QUEUE_FLAG_SCSI_PASSTHROUGH, sdev->request_queue);
1879 return sdev->request_queue;
1880}
1881
1882int scsi_mq_setup_tags(struct Scsi_Host *shost)
1883{
1884 unsigned int cmd_size, sgl_size;
1885
1886 sgl_size = max_t(unsigned int, sizeof(struct scatterlist),
1887 scsi_mq_inline_sgl_size(shost));
1888 cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size;
1889 if (scsi_host_get_prot(shost))
1890 cmd_size += sizeof(struct scsi_data_buffer) +
1891 sizeof(struct scatterlist) * SCSI_INLINE_PROT_SG_CNT;
1892
1893 memset(&shost->tag_set, 0, sizeof(shost->tag_set));
1894 if (shost->hostt->commit_rqs)
1895 shost->tag_set.ops = &scsi_mq_ops;
1896 else
1897 shost->tag_set.ops = &scsi_mq_ops_no_commit;
1898 shost->tag_set.nr_hw_queues = shost->nr_hw_queues ? : 1;
1899 shost->tag_set.queue_depth = shost->can_queue;
1900 shost->tag_set.cmd_size = cmd_size;
1901 shost->tag_set.numa_node = NUMA_NO_NODE;
1902 shost->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
1903 shost->tag_set.flags |=
1904 BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
1905 shost->tag_set.driver_data = shost;
1906
1907 return blk_mq_alloc_tag_set(&shost->tag_set);
1908}
1909
1910void scsi_mq_destroy_tags(struct Scsi_Host *shost)
1911{
1912 blk_mq_free_tag_set(&shost->tag_set);
1913}
1914
1915/**
1916 * scsi_device_from_queue - return sdev associated with a request_queue
1917 * @q: The request queue to return the sdev from
1918 *
1919 * Return the sdev associated with a request queue or NULL if the
1920 * request_queue does not reference a SCSI device.
1921 */
1922struct scsi_device *scsi_device_from_queue(struct request_queue *q)
1923{
1924 struct scsi_device *sdev = NULL;
1925
1926 if (q->mq_ops == &scsi_mq_ops_no_commit ||
1927 q->mq_ops == &scsi_mq_ops)
1928 sdev = q->queuedata;
1929 if (!sdev || !get_device(&sdev->sdev_gendev))
1930 sdev = NULL;
1931
1932 return sdev;
1933}
1934EXPORT_SYMBOL_GPL(scsi_device_from_queue);
1935
1936/*
1937 * Function: scsi_block_requests()
1938 *
1939 * Purpose: Utility function used by low-level drivers to prevent further
1940 * commands from being queued to the device.
1941 *
1942 * Arguments: shost - Host in question
1943 *
1944 * Returns: Nothing
1945 *
1946 * Lock status: No locks are assumed held.
1947 *
1948 * Notes: There is no timer nor any other means by which the requests
1949 * get unblocked other than the low-level driver calling
1950 * scsi_unblock_requests().
1951 */
1952void scsi_block_requests(struct Scsi_Host *shost)
1953{
1954 shost->host_self_blocked = 1;
1955}
1956EXPORT_SYMBOL(scsi_block_requests);
1957
1958/*
1959 * Function: scsi_unblock_requests()
1960 *
1961 * Purpose: Utility function used by low-level drivers to allow further
1962 * commands from being queued to the device.
1963 *
1964 * Arguments: shost - Host in question
1965 *
1966 * Returns: Nothing
1967 *
1968 * Lock status: No locks are assumed held.
1969 *
1970 * Notes: There is no timer nor any other means by which the requests
1971 * get unblocked other than the low-level driver calling
1972 * scsi_unblock_requests().
1973 *
1974 * This is done as an API function so that changes to the
1975 * internals of the scsi mid-layer won't require wholesale
1976 * changes to drivers that use this feature.
1977 */
1978void scsi_unblock_requests(struct Scsi_Host *shost)
1979{
1980 shost->host_self_blocked = 0;
1981 scsi_run_host_queues(shost);
1982}
1983EXPORT_SYMBOL(scsi_unblock_requests);
1984
1985int __init scsi_init_queue(void)
1986{
1987 scsi_sdb_cache = kmem_cache_create("scsi_data_buffer",
1988 sizeof(struct scsi_data_buffer),
1989 0, 0, NULL);
1990 if (!scsi_sdb_cache) {
1991 printk(KERN_ERR "SCSI: can't init scsi sdb cache\n");
1992 return -ENOMEM;
1993 }
1994
1995 return 0;
1996}
1997
1998void scsi_exit_queue(void)
1999{
2000 kmem_cache_destroy(scsi_sense_cache);
2001 kmem_cache_destroy(scsi_sense_isadma_cache);
2002 kmem_cache_destroy(scsi_sdb_cache);
2003}
2004
2005/**
2006 * scsi_mode_select - issue a mode select
2007 * @sdev: SCSI device to be queried
2008 * @pf: Page format bit (1 == standard, 0 == vendor specific)
2009 * @sp: Save page bit (0 == don't save, 1 == save)
2010 * @modepage: mode page being requested
2011 * @buffer: request buffer (may not be smaller than eight bytes)
2012 * @len: length of request buffer.
2013 * @timeout: command timeout
2014 * @retries: number of retries before failing
2015 * @data: returns a structure abstracting the mode header data
2016 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2017 * must be SCSI_SENSE_BUFFERSIZE big.
2018 *
2019 * Returns zero if successful; negative error number or scsi
2020 * status on error
2021 *
2022 */
2023int
2024scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
2025 unsigned char *buffer, int len, int timeout, int retries,
2026 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2027{
2028 unsigned char cmd[10];
2029 unsigned char *real_buffer;
2030 int ret;
2031
2032 memset(cmd, 0, sizeof(cmd));
2033 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
2034
2035 if (sdev->use_10_for_ms) {
2036 if (len > 65535)
2037 return -EINVAL;
2038 real_buffer = kmalloc(8 + len, GFP_KERNEL);
2039 if (!real_buffer)
2040 return -ENOMEM;
2041 memcpy(real_buffer + 8, buffer, len);
2042 len += 8;
2043 real_buffer[0] = 0;
2044 real_buffer[1] = 0;
2045 real_buffer[2] = data->medium_type;
2046 real_buffer[3] = data->device_specific;
2047 real_buffer[4] = data->longlba ? 0x01 : 0;
2048 real_buffer[5] = 0;
2049 real_buffer[6] = data->block_descriptor_length >> 8;
2050 real_buffer[7] = data->block_descriptor_length;
2051
2052 cmd[0] = MODE_SELECT_10;
2053 cmd[7] = len >> 8;
2054 cmd[8] = len;
2055 } else {
2056 if (len > 255 || data->block_descriptor_length > 255 ||
2057 data->longlba)
2058 return -EINVAL;
2059
2060 real_buffer = kmalloc(4 + len, GFP_KERNEL);
2061 if (!real_buffer)
2062 return -ENOMEM;
2063 memcpy(real_buffer + 4, buffer, len);
2064 len += 4;
2065 real_buffer[0] = 0;
2066 real_buffer[1] = data->medium_type;
2067 real_buffer[2] = data->device_specific;
2068 real_buffer[3] = data->block_descriptor_length;
2069
2070
2071 cmd[0] = MODE_SELECT;
2072 cmd[4] = len;
2073 }
2074
2075 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
2076 sshdr, timeout, retries, NULL);
2077 kfree(real_buffer);
2078 return ret;
2079}
2080EXPORT_SYMBOL_GPL(scsi_mode_select);
2081
2082/**
2083 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
2084 * @sdev: SCSI device to be queried
2085 * @dbd: set if mode sense will allow block descriptors to be returned
2086 * @modepage: mode page being requested
2087 * @buffer: request buffer (may not be smaller than eight bytes)
2088 * @len: length of request buffer.
2089 * @timeout: command timeout
2090 * @retries: number of retries before failing
2091 * @data: returns a structure abstracting the mode header data
2092 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2093 * must be SCSI_SENSE_BUFFERSIZE big.
2094 *
2095 * Returns zero if unsuccessful, or the header offset (either 4
2096 * or 8 depending on whether a six or ten byte command was
2097 * issued) if successful.
2098 */
2099int
2100scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
2101 unsigned char *buffer, int len, int timeout, int retries,
2102 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2103{
2104 unsigned char cmd[12];
2105 int use_10_for_ms;
2106 int header_length;
2107 int result, retry_count = retries;
2108 struct scsi_sense_hdr my_sshdr;
2109
2110 memset(data, 0, sizeof(*data));
2111 memset(&cmd[0], 0, 12);
2112 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
2113 cmd[2] = modepage;
2114
2115 /* caller might not be interested in sense, but we need it */
2116 if (!sshdr)
2117 sshdr = &my_sshdr;
2118
2119 retry:
2120 use_10_for_ms = sdev->use_10_for_ms;
2121
2122 if (use_10_for_ms) {
2123 if (len < 8)
2124 len = 8;
2125
2126 cmd[0] = MODE_SENSE_10;
2127 cmd[8] = len;
2128 header_length = 8;
2129 } else {
2130 if (len < 4)
2131 len = 4;
2132
2133 cmd[0] = MODE_SENSE;
2134 cmd[4] = len;
2135 header_length = 4;
2136 }
2137
2138 memset(buffer, 0, len);
2139
2140 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
2141 sshdr, timeout, retries, NULL);
2142
2143 /* This code looks awful: what it's doing is making sure an
2144 * ILLEGAL REQUEST sense return identifies the actual command
2145 * byte as the problem. MODE_SENSE commands can return
2146 * ILLEGAL REQUEST if the code page isn't supported */
2147
2148 if (use_10_for_ms && !scsi_status_is_good(result) &&
2149 driver_byte(result) == DRIVER_SENSE) {
2150 if (scsi_sense_valid(sshdr)) {
2151 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
2152 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
2153 /*
2154 * Invalid command operation code
2155 */
2156 sdev->use_10_for_ms = 0;
2157 goto retry;
2158 }
2159 }
2160 }
2161
2162 if(scsi_status_is_good(result)) {
2163 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
2164 (modepage == 6 || modepage == 8))) {
2165 /* Initio breakage? */
2166 header_length = 0;
2167 data->length = 13;
2168 data->medium_type = 0;
2169 data->device_specific = 0;
2170 data->longlba = 0;
2171 data->block_descriptor_length = 0;
2172 } else if(use_10_for_ms) {
2173 data->length = buffer[0]*256 + buffer[1] + 2;
2174 data->medium_type = buffer[2];
2175 data->device_specific = buffer[3];
2176 data->longlba = buffer[4] & 0x01;
2177 data->block_descriptor_length = buffer[6]*256
2178 + buffer[7];
2179 } else {
2180 data->length = buffer[0] + 1;
2181 data->medium_type = buffer[1];
2182 data->device_specific = buffer[2];
2183 data->block_descriptor_length = buffer[3];
2184 }
2185 data->header_length = header_length;
2186 } else if ((status_byte(result) == CHECK_CONDITION) &&
2187 scsi_sense_valid(sshdr) &&
2188 sshdr->sense_key == UNIT_ATTENTION && retry_count) {
2189 retry_count--;
2190 goto retry;
2191 }
2192
2193 return result;
2194}
2195EXPORT_SYMBOL(scsi_mode_sense);
2196
2197/**
2198 * scsi_test_unit_ready - test if unit is ready
2199 * @sdev: scsi device to change the state of.
2200 * @timeout: command timeout
2201 * @retries: number of retries before failing
2202 * @sshdr: outpout pointer for decoded sense information.
2203 *
2204 * Returns zero if unsuccessful or an error if TUR failed. For
2205 * removable media, UNIT_ATTENTION sets ->changed flag.
2206 **/
2207int
2208scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2209 struct scsi_sense_hdr *sshdr)
2210{
2211 char cmd[] = {
2212 TEST_UNIT_READY, 0, 0, 0, 0, 0,
2213 };
2214 int result;
2215
2216 /* try to eat the UNIT_ATTENTION if there are enough retries */
2217 do {
2218 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
2219 timeout, 1, NULL);
2220 if (sdev->removable && scsi_sense_valid(sshdr) &&
2221 sshdr->sense_key == UNIT_ATTENTION)
2222 sdev->changed = 1;
2223 } while (scsi_sense_valid(sshdr) &&
2224 sshdr->sense_key == UNIT_ATTENTION && --retries);
2225
2226 return result;
2227}
2228EXPORT_SYMBOL(scsi_test_unit_ready);
2229
2230/**
2231 * scsi_device_set_state - Take the given device through the device state model.
2232 * @sdev: scsi device to change the state of.
2233 * @state: state to change to.
2234 *
2235 * Returns zero if successful or an error if the requested
2236 * transition is illegal.
2237 */
2238int
2239scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2240{
2241 enum scsi_device_state oldstate = sdev->sdev_state;
2242
2243 if (state == oldstate)
2244 return 0;
2245
2246 switch (state) {
2247 case SDEV_CREATED:
2248 switch (oldstate) {
2249 case SDEV_CREATED_BLOCK:
2250 break;
2251 default:
2252 goto illegal;
2253 }
2254 break;
2255
2256 case SDEV_RUNNING:
2257 switch (oldstate) {
2258 case SDEV_CREATED:
2259 case SDEV_OFFLINE:
2260 case SDEV_TRANSPORT_OFFLINE:
2261 case SDEV_QUIESCE:
2262 case SDEV_BLOCK:
2263 break;
2264 default:
2265 goto illegal;
2266 }
2267 break;
2268
2269 case SDEV_QUIESCE:
2270 switch (oldstate) {
2271 case SDEV_RUNNING:
2272 case SDEV_OFFLINE:
2273 case SDEV_TRANSPORT_OFFLINE:
2274 break;
2275 default:
2276 goto illegal;
2277 }
2278 break;
2279
2280 case SDEV_OFFLINE:
2281 case SDEV_TRANSPORT_OFFLINE:
2282 switch (oldstate) {
2283 case SDEV_CREATED:
2284 case SDEV_RUNNING:
2285 case SDEV_QUIESCE:
2286 case SDEV_BLOCK:
2287 break;
2288 default:
2289 goto illegal;
2290 }
2291 break;
2292
2293 case SDEV_BLOCK:
2294 switch (oldstate) {
2295 case SDEV_RUNNING:
2296 case SDEV_CREATED_BLOCK:
2297 case SDEV_OFFLINE:
2298 break;
2299 default:
2300 goto illegal;
2301 }
2302 break;
2303
2304 case SDEV_CREATED_BLOCK:
2305 switch (oldstate) {
2306 case SDEV_CREATED:
2307 break;
2308 default:
2309 goto illegal;
2310 }
2311 break;
2312
2313 case SDEV_CANCEL:
2314 switch (oldstate) {
2315 case SDEV_CREATED:
2316 case SDEV_RUNNING:
2317 case SDEV_QUIESCE:
2318 case SDEV_OFFLINE:
2319 case SDEV_TRANSPORT_OFFLINE:
2320 break;
2321 default:
2322 goto illegal;
2323 }
2324 break;
2325
2326 case SDEV_DEL:
2327 switch (oldstate) {
2328 case SDEV_CREATED:
2329 case SDEV_RUNNING:
2330 case SDEV_OFFLINE:
2331 case SDEV_TRANSPORT_OFFLINE:
2332 case SDEV_CANCEL:
2333 case SDEV_BLOCK:
2334 case SDEV_CREATED_BLOCK:
2335 break;
2336 default:
2337 goto illegal;
2338 }
2339 break;
2340
2341 }
2342 sdev->sdev_state = state;
2343 return 0;
2344
2345 illegal:
2346 SCSI_LOG_ERROR_RECOVERY(1,
2347 sdev_printk(KERN_ERR, sdev,
2348 "Illegal state transition %s->%s",
2349 scsi_device_state_name(oldstate),
2350 scsi_device_state_name(state))
2351 );
2352 return -EINVAL;
2353}
2354EXPORT_SYMBOL(scsi_device_set_state);
2355
2356/**
2357 * sdev_evt_emit - emit a single SCSI device uevent
2358 * @sdev: associated SCSI device
2359 * @evt: event to emit
2360 *
2361 * Send a single uevent (scsi_event) to the associated scsi_device.
2362 */
2363static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2364{
2365 int idx = 0;
2366 char *envp[3];
2367
2368 switch (evt->evt_type) {
2369 case SDEV_EVT_MEDIA_CHANGE:
2370 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2371 break;
2372 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2373 scsi_rescan_device(&sdev->sdev_gendev);
2374 envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2375 break;
2376 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2377 envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2378 break;
2379 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2380 envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2381 break;
2382 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2383 envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2384 break;
2385 case SDEV_EVT_LUN_CHANGE_REPORTED:
2386 envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2387 break;
2388 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2389 envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
2390 break;
2391 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2392 envp[idx++] = "SDEV_UA=POWER_ON_RESET_OCCURRED";
2393 break;
2394 default:
2395 /* do nothing */
2396 break;
2397 }
2398
2399 envp[idx++] = NULL;
2400
2401 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2402}
2403
2404/**
2405 * sdev_evt_thread - send a uevent for each scsi event
2406 * @work: work struct for scsi_device
2407 *
2408 * Dispatch queued events to their associated scsi_device kobjects
2409 * as uevents.
2410 */
2411void scsi_evt_thread(struct work_struct *work)
2412{
2413 struct scsi_device *sdev;
2414 enum scsi_device_event evt_type;
2415 LIST_HEAD(event_list);
2416
2417 sdev = container_of(work, struct scsi_device, event_work);
2418
2419 for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
2420 if (test_and_clear_bit(evt_type, sdev->pending_events))
2421 sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
2422
2423 while (1) {
2424 struct scsi_event *evt;
2425 struct list_head *this, *tmp;
2426 unsigned long flags;
2427
2428 spin_lock_irqsave(&sdev->list_lock, flags);
2429 list_splice_init(&sdev->event_list, &event_list);
2430 spin_unlock_irqrestore(&sdev->list_lock, flags);
2431
2432 if (list_empty(&event_list))
2433 break;
2434
2435 list_for_each_safe(this, tmp, &event_list) {
2436 evt = list_entry(this, struct scsi_event, node);
2437 list_del(&evt->node);
2438 scsi_evt_emit(sdev, evt);
2439 kfree(evt);
2440 }
2441 }
2442}
2443
2444/**
2445 * sdev_evt_send - send asserted event to uevent thread
2446 * @sdev: scsi_device event occurred on
2447 * @evt: event to send
2448 *
2449 * Assert scsi device event asynchronously.
2450 */
2451void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2452{
2453 unsigned long flags;
2454
2455#if 0
2456 /* FIXME: currently this check eliminates all media change events
2457 * for polled devices. Need to update to discriminate between AN
2458 * and polled events */
2459 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2460 kfree(evt);
2461 return;
2462 }
2463#endif
2464
2465 spin_lock_irqsave(&sdev->list_lock, flags);
2466 list_add_tail(&evt->node, &sdev->event_list);
2467 schedule_work(&sdev->event_work);
2468 spin_unlock_irqrestore(&sdev->list_lock, flags);
2469}
2470EXPORT_SYMBOL_GPL(sdev_evt_send);
2471
2472/**
2473 * sdev_evt_alloc - allocate a new scsi event
2474 * @evt_type: type of event to allocate
2475 * @gfpflags: GFP flags for allocation
2476 *
2477 * Allocates and returns a new scsi_event.
2478 */
2479struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2480 gfp_t gfpflags)
2481{
2482 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2483 if (!evt)
2484 return NULL;
2485
2486 evt->evt_type = evt_type;
2487 INIT_LIST_HEAD(&evt->node);
2488
2489 /* evt_type-specific initialization, if any */
2490 switch (evt_type) {
2491 case SDEV_EVT_MEDIA_CHANGE:
2492 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2493 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2494 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2495 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2496 case SDEV_EVT_LUN_CHANGE_REPORTED:
2497 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2498 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2499 default:
2500 /* do nothing */
2501 break;
2502 }
2503
2504 return evt;
2505}
2506EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2507
2508/**
2509 * sdev_evt_send_simple - send asserted event to uevent thread
2510 * @sdev: scsi_device event occurred on
2511 * @evt_type: type of event to send
2512 * @gfpflags: GFP flags for allocation
2513 *
2514 * Assert scsi device event asynchronously, given an event type.
2515 */
2516void sdev_evt_send_simple(struct scsi_device *sdev,
2517 enum scsi_device_event evt_type, gfp_t gfpflags)
2518{
2519 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2520 if (!evt) {
2521 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2522 evt_type);
2523 return;
2524 }
2525
2526 sdev_evt_send(sdev, evt);
2527}
2528EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2529
2530/**
2531 * scsi_device_quiesce - Block user issued commands.
2532 * @sdev: scsi device to quiesce.
2533 *
2534 * This works by trying to transition to the SDEV_QUIESCE state
2535 * (which must be a legal transition). When the device is in this
2536 * state, only special requests will be accepted, all others will
2537 * be deferred. Since special requests may also be requeued requests,
2538 * a successful return doesn't guarantee the device will be
2539 * totally quiescent.
2540 *
2541 * Must be called with user context, may sleep.
2542 *
2543 * Returns zero if unsuccessful or an error if not.
2544 */
2545int
2546scsi_device_quiesce(struct scsi_device *sdev)
2547{
2548 struct request_queue *q = sdev->request_queue;
2549 int err;
2550
2551 /*
2552 * It is allowed to call scsi_device_quiesce() multiple times from
2553 * the same context but concurrent scsi_device_quiesce() calls are
2554 * not allowed.
2555 */
2556 WARN_ON_ONCE(sdev->quiesced_by && sdev->quiesced_by != current);
2557
2558 if (sdev->quiesced_by == current)
2559 return 0;
2560
2561 blk_set_pm_only(q);
2562
2563 blk_mq_freeze_queue(q);
2564 /*
2565 * Ensure that the effect of blk_set_pm_only() will be visible
2566 * for percpu_ref_tryget() callers that occur after the queue
2567 * unfreeze even if the queue was already frozen before this function
2568 * was called. See also https://lwn.net/Articles/573497/.
2569 */
2570 synchronize_rcu();
2571 blk_mq_unfreeze_queue(q);
2572
2573 mutex_lock(&sdev->state_mutex);
2574 err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2575 if (err == 0)
2576 sdev->quiesced_by = current;
2577 else
2578 blk_clear_pm_only(q);
2579 mutex_unlock(&sdev->state_mutex);
2580
2581 return err;
2582}
2583EXPORT_SYMBOL(scsi_device_quiesce);
2584
2585/**
2586 * scsi_device_resume - Restart user issued commands to a quiesced device.
2587 * @sdev: scsi device to resume.
2588 *
2589 * Moves the device from quiesced back to running and restarts the
2590 * queues.
2591 *
2592 * Must be called with user context, may sleep.
2593 */
2594void scsi_device_resume(struct scsi_device *sdev)
2595{
2596 /* check if the device state was mutated prior to resume, and if
2597 * so assume the state is being managed elsewhere (for example
2598 * device deleted during suspend)
2599 */
2600 mutex_lock(&sdev->state_mutex);
2601 if (sdev->quiesced_by) {
2602 sdev->quiesced_by = NULL;
2603 blk_clear_pm_only(sdev->request_queue);
2604 }
2605 if (sdev->sdev_state == SDEV_QUIESCE)
2606 scsi_device_set_state(sdev, SDEV_RUNNING);
2607 mutex_unlock(&sdev->state_mutex);
2608}
2609EXPORT_SYMBOL(scsi_device_resume);
2610
2611static void
2612device_quiesce_fn(struct scsi_device *sdev, void *data)
2613{
2614 scsi_device_quiesce(sdev);
2615}
2616
2617void
2618scsi_target_quiesce(struct scsi_target *starget)
2619{
2620 starget_for_each_device(starget, NULL, device_quiesce_fn);
2621}
2622EXPORT_SYMBOL(scsi_target_quiesce);
2623
2624static void
2625device_resume_fn(struct scsi_device *sdev, void *data)
2626{
2627 scsi_device_resume(sdev);
2628}
2629
2630void
2631scsi_target_resume(struct scsi_target *starget)
2632{
2633 starget_for_each_device(starget, NULL, device_resume_fn);
2634}
2635EXPORT_SYMBOL(scsi_target_resume);
2636
2637/**
2638 * scsi_internal_device_block_nowait - try to transition to the SDEV_BLOCK state
2639 * @sdev: device to block
2640 *
2641 * Pause SCSI command processing on the specified device. Does not sleep.
2642 *
2643 * Returns zero if successful or a negative error code upon failure.
2644 *
2645 * Notes:
2646 * This routine transitions the device to the SDEV_BLOCK state (which must be
2647 * a legal transition). When the device is in this state, command processing
2648 * is paused until the device leaves the SDEV_BLOCK state. See also
2649 * scsi_internal_device_unblock_nowait().
2650 */
2651int scsi_internal_device_block_nowait(struct scsi_device *sdev)
2652{
2653 struct request_queue *q = sdev->request_queue;
2654 int err = 0;
2655
2656 err = scsi_device_set_state(sdev, SDEV_BLOCK);
2657 if (err) {
2658 err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2659
2660 if (err)
2661 return err;
2662 }
2663
2664 /*
2665 * The device has transitioned to SDEV_BLOCK. Stop the
2666 * block layer from calling the midlayer with this device's
2667 * request queue.
2668 */
2669 blk_mq_quiesce_queue_nowait(q);
2670 return 0;
2671}
2672EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait);
2673
2674/**
2675 * scsi_internal_device_block - try to transition to the SDEV_BLOCK state
2676 * @sdev: device to block
2677 *
2678 * Pause SCSI command processing on the specified device and wait until all
2679 * ongoing scsi_request_fn() / scsi_queue_rq() calls have finished. May sleep.
2680 *
2681 * Returns zero if successful or a negative error code upon failure.
2682 *
2683 * Note:
2684 * This routine transitions the device to the SDEV_BLOCK state (which must be
2685 * a legal transition). When the device is in this state, command processing
2686 * is paused until the device leaves the SDEV_BLOCK state. See also
2687 * scsi_internal_device_unblock().
2688 */
2689static int scsi_internal_device_block(struct scsi_device *sdev)
2690{
2691 struct request_queue *q = sdev->request_queue;
2692 int err;
2693
2694 mutex_lock(&sdev->state_mutex);
2695 err = scsi_internal_device_block_nowait(sdev);
2696 if (err == 0)
2697 blk_mq_quiesce_queue(q);
2698 mutex_unlock(&sdev->state_mutex);
2699
2700 return err;
2701}
2702
2703void scsi_start_queue(struct scsi_device *sdev)
2704{
2705 struct request_queue *q = sdev->request_queue;
2706
2707 blk_mq_unquiesce_queue(q);
2708}
2709
2710/**
2711 * scsi_internal_device_unblock_nowait - resume a device after a block request
2712 * @sdev: device to resume
2713 * @new_state: state to set the device to after unblocking
2714 *
2715 * Restart the device queue for a previously suspended SCSI device. Does not
2716 * sleep.
2717 *
2718 * Returns zero if successful or a negative error code upon failure.
2719 *
2720 * Notes:
2721 * This routine transitions the device to the SDEV_RUNNING state or to one of
2722 * the offline states (which must be a legal transition) allowing the midlayer
2723 * to goose the queue for this device.
2724 */
2725int scsi_internal_device_unblock_nowait(struct scsi_device *sdev,
2726 enum scsi_device_state new_state)
2727{
2728 switch (new_state) {
2729 case SDEV_RUNNING:
2730 case SDEV_TRANSPORT_OFFLINE:
2731 break;
2732 default:
2733 return -EINVAL;
2734 }
2735
2736 /*
2737 * Try to transition the scsi device to SDEV_RUNNING or one of the
2738 * offlined states and goose the device queue if successful.
2739 */
2740 switch (sdev->sdev_state) {
2741 case SDEV_BLOCK:
2742 case SDEV_TRANSPORT_OFFLINE:
2743 sdev->sdev_state = new_state;
2744 break;
2745 case SDEV_CREATED_BLOCK:
2746 if (new_state == SDEV_TRANSPORT_OFFLINE ||
2747 new_state == SDEV_OFFLINE)
2748 sdev->sdev_state = new_state;
2749 else
2750 sdev->sdev_state = SDEV_CREATED;
2751 break;
2752 case SDEV_CANCEL:
2753 case SDEV_OFFLINE:
2754 break;
2755 default:
2756 return -EINVAL;
2757 }
2758 scsi_start_queue(sdev);
2759
2760 return 0;
2761}
2762EXPORT_SYMBOL_GPL(scsi_internal_device_unblock_nowait);
2763
2764/**
2765 * scsi_internal_device_unblock - resume a device after a block request
2766 * @sdev: device to resume
2767 * @new_state: state to set the device to after unblocking
2768 *
2769 * Restart the device queue for a previously suspended SCSI device. May sleep.
2770 *
2771 * Returns zero if successful or a negative error code upon failure.
2772 *
2773 * Notes:
2774 * This routine transitions the device to the SDEV_RUNNING state or to one of
2775 * the offline states (which must be a legal transition) allowing the midlayer
2776 * to goose the queue for this device.
2777 */
2778static int scsi_internal_device_unblock(struct scsi_device *sdev,
2779 enum scsi_device_state new_state)
2780{
2781 int ret;
2782
2783 mutex_lock(&sdev->state_mutex);
2784 ret = scsi_internal_device_unblock_nowait(sdev, new_state);
2785 mutex_unlock(&sdev->state_mutex);
2786
2787 return ret;
2788}
2789
2790static void
2791device_block(struct scsi_device *sdev, void *data)
2792{
2793 int ret;
2794
2795 ret = scsi_internal_device_block(sdev);
2796
2797 WARN_ONCE(ret, "scsi_internal_device_block(%s) failed: ret = %d\n",
2798 dev_name(&sdev->sdev_gendev), ret);
2799}
2800
2801static int
2802target_block(struct device *dev, void *data)
2803{
2804 if (scsi_is_target_device(dev))
2805 starget_for_each_device(to_scsi_target(dev), NULL,
2806 device_block);
2807 return 0;
2808}
2809
2810void
2811scsi_target_block(struct device *dev)
2812{
2813 if (scsi_is_target_device(dev))
2814 starget_for_each_device(to_scsi_target(dev), NULL,
2815 device_block);
2816 else
2817 device_for_each_child(dev, NULL, target_block);
2818}
2819EXPORT_SYMBOL_GPL(scsi_target_block);
2820
2821static void
2822device_unblock(struct scsi_device *sdev, void *data)
2823{
2824 scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
2825}
2826
2827static int
2828target_unblock(struct device *dev, void *data)
2829{
2830 if (scsi_is_target_device(dev))
2831 starget_for_each_device(to_scsi_target(dev), data,
2832 device_unblock);
2833 return 0;
2834}
2835
2836void
2837scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
2838{
2839 if (scsi_is_target_device(dev))
2840 starget_for_each_device(to_scsi_target(dev), &new_state,
2841 device_unblock);
2842 else
2843 device_for_each_child(dev, &new_state, target_unblock);
2844}
2845EXPORT_SYMBOL_GPL(scsi_target_unblock);
2846
2847/**
2848 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
2849 * @sgl: scatter-gather list
2850 * @sg_count: number of segments in sg
2851 * @offset: offset in bytes into sg, on return offset into the mapped area
2852 * @len: bytes to map, on return number of bytes mapped
2853 *
2854 * Returns virtual address of the start of the mapped page
2855 */
2856void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
2857 size_t *offset, size_t *len)
2858{
2859 int i;
2860 size_t sg_len = 0, len_complete = 0;
2861 struct scatterlist *sg;
2862 struct page *page;
2863
2864 WARN_ON(!irqs_disabled());
2865
2866 for_each_sg(sgl, sg, sg_count, i) {
2867 len_complete = sg_len; /* Complete sg-entries */
2868 sg_len += sg->length;
2869 if (sg_len > *offset)
2870 break;
2871 }
2872
2873 if (unlikely(i == sg_count)) {
2874 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
2875 "elements %d\n",
2876 __func__, sg_len, *offset, sg_count);
2877 WARN_ON(1);
2878 return NULL;
2879 }
2880
2881 /* Offset starting from the beginning of first page in this sg-entry */
2882 *offset = *offset - len_complete + sg->offset;
2883
2884 /* Assumption: contiguous pages can be accessed as "page + i" */
2885 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
2886 *offset &= ~PAGE_MASK;
2887
2888 /* Bytes in this sg-entry from *offset to the end of the page */
2889 sg_len = PAGE_SIZE - *offset;
2890 if (*len > sg_len)
2891 *len = sg_len;
2892
2893 return kmap_atomic(page);
2894}
2895EXPORT_SYMBOL(scsi_kmap_atomic_sg);
2896
2897/**
2898 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
2899 * @virt: virtual address to be unmapped
2900 */
2901void scsi_kunmap_atomic_sg(void *virt)
2902{
2903 kunmap_atomic(virt);
2904}
2905EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
2906
2907void sdev_disable_disk_events(struct scsi_device *sdev)
2908{
2909 atomic_inc(&sdev->disk_events_disable_depth);
2910}
2911EXPORT_SYMBOL(sdev_disable_disk_events);
2912
2913void sdev_enable_disk_events(struct scsi_device *sdev)
2914{
2915 if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0))
2916 return;
2917 atomic_dec(&sdev->disk_events_disable_depth);
2918}
2919EXPORT_SYMBOL(sdev_enable_disk_events);
2920
2921/**
2922 * scsi_vpd_lun_id - return a unique device identification
2923 * @sdev: SCSI device
2924 * @id: buffer for the identification
2925 * @id_len: length of the buffer
2926 *
2927 * Copies a unique device identification into @id based
2928 * on the information in the VPD page 0x83 of the device.
2929 * The string will be formatted as a SCSI name string.
2930 *
2931 * Returns the length of the identification or error on failure.
2932 * If the identifier is longer than the supplied buffer the actual
2933 * identifier length is returned and the buffer is not zero-padded.
2934 */
2935int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len)
2936{
2937 u8 cur_id_type = 0xff;
2938 u8 cur_id_size = 0;
2939 const unsigned char *d, *cur_id_str;
2940 const struct scsi_vpd *vpd_pg83;
2941 int id_size = -EINVAL;
2942
2943 rcu_read_lock();
2944 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
2945 if (!vpd_pg83) {
2946 rcu_read_unlock();
2947 return -ENXIO;
2948 }
2949
2950 /*
2951 * Look for the correct descriptor.
2952 * Order of preference for lun descriptor:
2953 * - SCSI name string
2954 * - NAA IEEE Registered Extended
2955 * - EUI-64 based 16-byte
2956 * - EUI-64 based 12-byte
2957 * - NAA IEEE Registered
2958 * - NAA IEEE Extended
2959 * - T10 Vendor ID
2960 * as longer descriptors reduce the likelyhood
2961 * of identification clashes.
2962 */
2963
2964 /* The id string must be at least 20 bytes + terminating NULL byte */
2965 if (id_len < 21) {
2966 rcu_read_unlock();
2967 return -EINVAL;
2968 }
2969
2970 memset(id, 0, id_len);
2971 d = vpd_pg83->data + 4;
2972 while (d < vpd_pg83->data + vpd_pg83->len) {
2973 /* Skip designators not referring to the LUN */
2974 if ((d[1] & 0x30) != 0x00)
2975 goto next_desig;
2976
2977 switch (d[1] & 0xf) {
2978 case 0x1:
2979 /* T10 Vendor ID */
2980 if (cur_id_size > d[3])
2981 break;
2982 /* Prefer anything */
2983 if (cur_id_type > 0x01 && cur_id_type != 0xff)
2984 break;
2985 cur_id_size = d[3];
2986 if (cur_id_size + 4 > id_len)
2987 cur_id_size = id_len - 4;
2988 cur_id_str = d + 4;
2989 cur_id_type = d[1] & 0xf;
2990 id_size = snprintf(id, id_len, "t10.%*pE",
2991 cur_id_size, cur_id_str);
2992 break;
2993 case 0x2:
2994 /* EUI-64 */
2995 if (cur_id_size > d[3])
2996 break;
2997 /* Prefer NAA IEEE Registered Extended */
2998 if (cur_id_type == 0x3 &&
2999 cur_id_size == d[3])
3000 break;
3001 cur_id_size = d[3];
3002 cur_id_str = d + 4;
3003 cur_id_type = d[1] & 0xf;
3004 switch (cur_id_size) {
3005 case 8:
3006 id_size = snprintf(id, id_len,
3007 "eui.%8phN",
3008 cur_id_str);
3009 break;
3010 case 12:
3011 id_size = snprintf(id, id_len,
3012 "eui.%12phN",
3013 cur_id_str);
3014 break;
3015 case 16:
3016 id_size = snprintf(id, id_len,
3017 "eui.%16phN",
3018 cur_id_str);
3019 break;
3020 default:
3021 cur_id_size = 0;
3022 break;
3023 }
3024 break;
3025 case 0x3:
3026 /* NAA */
3027 if (cur_id_size > d[3])
3028 break;
3029 cur_id_size = d[3];
3030 cur_id_str = d + 4;
3031 cur_id_type = d[1] & 0xf;
3032 switch (cur_id_size) {
3033 case 8:
3034 id_size = snprintf(id, id_len,
3035 "naa.%8phN",
3036 cur_id_str);
3037 break;
3038 case 16:
3039 id_size = snprintf(id, id_len,
3040 "naa.%16phN",
3041 cur_id_str);
3042 break;
3043 default:
3044 cur_id_size = 0;
3045 break;
3046 }
3047 break;
3048 case 0x8:
3049 /* SCSI name string */
3050 if (cur_id_size + 4 > d[3])
3051 break;
3052 /* Prefer others for truncated descriptor */
3053 if (cur_id_size && d[3] > id_len)
3054 break;
3055 cur_id_size = id_size = d[3];
3056 cur_id_str = d + 4;
3057 cur_id_type = d[1] & 0xf;
3058 if (cur_id_size >= id_len)
3059 cur_id_size = id_len - 1;
3060 memcpy(id, cur_id_str, cur_id_size);
3061 /* Decrease priority for truncated descriptor */
3062 if (cur_id_size != id_size)
3063 cur_id_size = 6;
3064 break;
3065 default:
3066 break;
3067 }
3068next_desig:
3069 d += d[3] + 4;
3070 }
3071 rcu_read_unlock();
3072
3073 return id_size;
3074}
3075EXPORT_SYMBOL(scsi_vpd_lun_id);
3076
3077/*
3078 * scsi_vpd_tpg_id - return a target port group identifier
3079 * @sdev: SCSI device
3080 *
3081 * Returns the Target Port Group identifier from the information
3082 * froom VPD page 0x83 of the device.
3083 *
3084 * Returns the identifier or error on failure.
3085 */
3086int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id)
3087{
3088 const unsigned char *d;
3089 const struct scsi_vpd *vpd_pg83;
3090 int group_id = -EAGAIN, rel_port = -1;
3091
3092 rcu_read_lock();
3093 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3094 if (!vpd_pg83) {
3095 rcu_read_unlock();
3096 return -ENXIO;
3097 }
3098
3099 d = vpd_pg83->data + 4;
3100 while (d < vpd_pg83->data + vpd_pg83->len) {
3101 switch (d[1] & 0xf) {
3102 case 0x4:
3103 /* Relative target port */
3104 rel_port = get_unaligned_be16(&d[6]);
3105 break;
3106 case 0x5:
3107 /* Target port group */
3108 group_id = get_unaligned_be16(&d[6]);
3109 break;
3110 default:
3111 break;
3112 }
3113 d += d[3] + 4;
3114 }
3115 rcu_read_unlock();
3116
3117 if (group_id >= 0 && rel_id && rel_port != -1)
3118 *rel_id = rel_port;
3119
3120 return group_id;
3121}
3122EXPORT_SYMBOL(scsi_vpd_tpg_id);