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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/*
2 * Copyright (C) 1999 Eric Youngdale
3 * Copyright (C) 2014 Christoph Hellwig
4 *
5 * SCSI queueing library.
6 * Initial versions: Eric Youngdale (eric@andante.org).
7 * Based upon conversations with large numbers
8 * of people at Linux Expo.
9 */
10
11#include <linux/bio.h>
12#include <linux/bitops.h>
13#include <linux/blkdev.h>
14#include <linux/completion.h>
15#include <linux/kernel.h>
16#include <linux/export.h>
17#include <linux/init.h>
18#include <linux/pci.h>
19#include <linux/delay.h>
20#include <linux/hardirq.h>
21#include <linux/scatterlist.h>
22#include <linux/blk-mq.h>
23#include <linux/ratelimit.h>
24#include <asm/unaligned.h>
25
26#include <scsi/scsi.h>
27#include <scsi/scsi_cmnd.h>
28#include <scsi/scsi_dbg.h>
29#include <scsi/scsi_device.h>
30#include <scsi/scsi_driver.h>
31#include <scsi/scsi_eh.h>
32#include <scsi/scsi_host.h>
33#include <scsi/scsi_dh.h>
34
35#include <trace/events/scsi.h>
36
37#include "scsi_priv.h"
38#include "scsi_logging.h"
39
40
41struct kmem_cache *scsi_sdb_cache;
42
43/*
44 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
45 * not change behaviour from the previous unplug mechanism, experimentation
46 * may prove this needs changing.
47 */
48#define SCSI_QUEUE_DELAY 3
49
50static void
51scsi_set_blocked(struct scsi_cmnd *cmd, int reason)
52{
53 struct Scsi_Host *host = cmd->device->host;
54 struct scsi_device *device = cmd->device;
55 struct scsi_target *starget = scsi_target(device);
56
57 /*
58 * Set the appropriate busy bit for the device/host.
59 *
60 * If the host/device isn't busy, assume that something actually
61 * completed, and that we should be able to queue a command now.
62 *
63 * Note that the prior mid-layer assumption that any host could
64 * always queue at least one command is now broken. The mid-layer
65 * will implement a user specifiable stall (see
66 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
67 * if a command is requeued with no other commands outstanding
68 * either for the device or for the host.
69 */
70 switch (reason) {
71 case SCSI_MLQUEUE_HOST_BUSY:
72 atomic_set(&host->host_blocked, host->max_host_blocked);
73 break;
74 case SCSI_MLQUEUE_DEVICE_BUSY:
75 case SCSI_MLQUEUE_EH_RETRY:
76 atomic_set(&device->device_blocked,
77 device->max_device_blocked);
78 break;
79 case SCSI_MLQUEUE_TARGET_BUSY:
80 atomic_set(&starget->target_blocked,
81 starget->max_target_blocked);
82 break;
83 }
84}
85
86static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd)
87{
88 struct scsi_device *sdev = cmd->device;
89
90 blk_mq_requeue_request(cmd->request, true);
91 put_device(&sdev->sdev_gendev);
92}
93
94/**
95 * __scsi_queue_insert - private queue insertion
96 * @cmd: The SCSI command being requeued
97 * @reason: The reason for the requeue
98 * @unbusy: Whether the queue should be unbusied
99 *
100 * This is a private queue insertion. The public interface
101 * scsi_queue_insert() always assumes the queue should be unbusied
102 * because it's always called before the completion. This function is
103 * for a requeue after completion, which should only occur in this
104 * file.
105 */
106static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy)
107{
108 struct scsi_device *device = cmd->device;
109 struct request_queue *q = device->request_queue;
110 unsigned long flags;
111
112 SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd,
113 "Inserting command %p into mlqueue\n", cmd));
114
115 scsi_set_blocked(cmd, reason);
116
117 /*
118 * Decrement the counters, since these commands are no longer
119 * active on the host/device.
120 */
121 if (unbusy)
122 scsi_device_unbusy(device);
123
124 /*
125 * Requeue this command. It will go before all other commands
126 * that are already in the queue. Schedule requeue work under
127 * lock such that the kblockd_schedule_work() call happens
128 * before blk_cleanup_queue() finishes.
129 */
130 cmd->result = 0;
131 if (q->mq_ops) {
132 scsi_mq_requeue_cmd(cmd);
133 return;
134 }
135 spin_lock_irqsave(q->queue_lock, flags);
136 blk_requeue_request(q, cmd->request);
137 kblockd_schedule_work(&device->requeue_work);
138 spin_unlock_irqrestore(q->queue_lock, flags);
139}
140
141/*
142 * Function: scsi_queue_insert()
143 *
144 * Purpose: Insert a command in the midlevel queue.
145 *
146 * Arguments: cmd - command that we are adding to queue.
147 * reason - why we are inserting command to queue.
148 *
149 * Lock status: Assumed that lock is not held upon entry.
150 *
151 * Returns: Nothing.
152 *
153 * Notes: We do this for one of two cases. Either the host is busy
154 * and it cannot accept any more commands for the time being,
155 * or the device returned QUEUE_FULL and can accept no more
156 * commands.
157 * Notes: This could be called either from an interrupt context or a
158 * normal process context.
159 */
160void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
161{
162 __scsi_queue_insert(cmd, reason, 1);
163}
164
165static int __scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
166 int data_direction, void *buffer, unsigned bufflen,
167 unsigned char *sense, int timeout, int retries, u64 flags,
168 req_flags_t rq_flags, int *resid)
169{
170 struct request *req;
171 int write = (data_direction == DMA_TO_DEVICE);
172 int ret = DRIVER_ERROR << 24;
173
174 req = blk_get_request(sdev->request_queue, write, __GFP_RECLAIM);
175 if (IS_ERR(req))
176 return ret;
177 blk_rq_set_block_pc(req);
178
179 if (bufflen && blk_rq_map_kern(sdev->request_queue, req,
180 buffer, bufflen, __GFP_RECLAIM))
181 goto out;
182
183 req->cmd_len = COMMAND_SIZE(cmd[0]);
184 memcpy(req->cmd, cmd, req->cmd_len);
185 req->sense = sense;
186 req->sense_len = 0;
187 req->retries = retries;
188 req->timeout = timeout;
189 req->cmd_flags |= flags;
190 req->rq_flags |= rq_flags | RQF_QUIET | RQF_PREEMPT;
191
192 /*
193 * head injection *required* here otherwise quiesce won't work
194 */
195 blk_execute_rq(req->q, NULL, req, 1);
196
197 /*
198 * Some devices (USB mass-storage in particular) may transfer
199 * garbage data together with a residue indicating that the data
200 * is invalid. Prevent the garbage from being misinterpreted
201 * and prevent security leaks by zeroing out the excess data.
202 */
203 if (unlikely(req->resid_len > 0 && req->resid_len <= bufflen))
204 memset(buffer + (bufflen - req->resid_len), 0, req->resid_len);
205
206 if (resid)
207 *resid = req->resid_len;
208 ret = req->errors;
209 out:
210 blk_put_request(req);
211
212 return ret;
213}
214
215/**
216 * scsi_execute - insert request and wait for the result
217 * @sdev: scsi device
218 * @cmd: scsi command
219 * @data_direction: data direction
220 * @buffer: data buffer
221 * @bufflen: len of buffer
222 * @sense: optional sense buffer
223 * @timeout: request timeout in seconds
224 * @retries: number of times to retry request
225 * @flags: or into request flags;
226 * @resid: optional residual length
227 *
228 * returns the req->errors value which is the scsi_cmnd result
229 * field.
230 */
231int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
232 int data_direction, void *buffer, unsigned bufflen,
233 unsigned char *sense, int timeout, int retries, u64 flags,
234 int *resid)
235{
236 return __scsi_execute(sdev, cmd, data_direction, buffer, bufflen, sense,
237 timeout, retries, flags, 0, resid);
238}
239EXPORT_SYMBOL(scsi_execute);
240
241int scsi_execute_req_flags(struct scsi_device *sdev, const unsigned char *cmd,
242 int data_direction, void *buffer, unsigned bufflen,
243 struct scsi_sense_hdr *sshdr, int timeout, int retries,
244 int *resid, u64 flags, req_flags_t rq_flags)
245{
246 char *sense = NULL;
247 int result;
248
249 if (sshdr) {
250 sense = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO);
251 if (!sense)
252 return DRIVER_ERROR << 24;
253 }
254 result = __scsi_execute(sdev, cmd, data_direction, buffer, bufflen,
255 sense, timeout, retries, flags, rq_flags, resid);
256 if (sshdr)
257 scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr);
258
259 kfree(sense);
260 return result;
261}
262EXPORT_SYMBOL(scsi_execute_req_flags);
263
264/*
265 * Function: scsi_init_cmd_errh()
266 *
267 * Purpose: Initialize cmd fields related to error handling.
268 *
269 * Arguments: cmd - command that is ready to be queued.
270 *
271 * Notes: This function has the job of initializing a number of
272 * fields related to error handling. Typically this will
273 * be called once for each command, as required.
274 */
275static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
276{
277 cmd->serial_number = 0;
278 scsi_set_resid(cmd, 0);
279 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
280 if (cmd->cmd_len == 0)
281 cmd->cmd_len = scsi_command_size(cmd->cmnd);
282}
283
284void scsi_device_unbusy(struct scsi_device *sdev)
285{
286 struct Scsi_Host *shost = sdev->host;
287 struct scsi_target *starget = scsi_target(sdev);
288 unsigned long flags;
289
290 atomic_dec(&shost->host_busy);
291 if (starget->can_queue > 0)
292 atomic_dec(&starget->target_busy);
293
294 if (unlikely(scsi_host_in_recovery(shost) &&
295 (shost->host_failed || shost->host_eh_scheduled))) {
296 spin_lock_irqsave(shost->host_lock, flags);
297 scsi_eh_wakeup(shost);
298 spin_unlock_irqrestore(shost->host_lock, flags);
299 }
300
301 atomic_dec(&sdev->device_busy);
302}
303
304static void scsi_kick_queue(struct request_queue *q)
305{
306 if (q->mq_ops)
307 blk_mq_start_hw_queues(q);
308 else
309 blk_run_queue(q);
310}
311
312/*
313 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
314 * and call blk_run_queue for all the scsi_devices on the target -
315 * including current_sdev first.
316 *
317 * Called with *no* scsi locks held.
318 */
319static void scsi_single_lun_run(struct scsi_device *current_sdev)
320{
321 struct Scsi_Host *shost = current_sdev->host;
322 struct scsi_device *sdev, *tmp;
323 struct scsi_target *starget = scsi_target(current_sdev);
324 unsigned long flags;
325
326 spin_lock_irqsave(shost->host_lock, flags);
327 starget->starget_sdev_user = NULL;
328 spin_unlock_irqrestore(shost->host_lock, flags);
329
330 /*
331 * Call blk_run_queue for all LUNs on the target, starting with
332 * current_sdev. We race with others (to set starget_sdev_user),
333 * but in most cases, we will be first. Ideally, each LU on the
334 * target would get some limited time or requests on the target.
335 */
336 scsi_kick_queue(current_sdev->request_queue);
337
338 spin_lock_irqsave(shost->host_lock, flags);
339 if (starget->starget_sdev_user)
340 goto out;
341 list_for_each_entry_safe(sdev, tmp, &starget->devices,
342 same_target_siblings) {
343 if (sdev == current_sdev)
344 continue;
345 if (scsi_device_get(sdev))
346 continue;
347
348 spin_unlock_irqrestore(shost->host_lock, flags);
349 scsi_kick_queue(sdev->request_queue);
350 spin_lock_irqsave(shost->host_lock, flags);
351
352 scsi_device_put(sdev);
353 }
354 out:
355 spin_unlock_irqrestore(shost->host_lock, flags);
356}
357
358static inline bool scsi_device_is_busy(struct scsi_device *sdev)
359{
360 if (atomic_read(&sdev->device_busy) >= sdev->queue_depth)
361 return true;
362 if (atomic_read(&sdev->device_blocked) > 0)
363 return true;
364 return false;
365}
366
367static inline bool scsi_target_is_busy(struct scsi_target *starget)
368{
369 if (starget->can_queue > 0) {
370 if (atomic_read(&starget->target_busy) >= starget->can_queue)
371 return true;
372 if (atomic_read(&starget->target_blocked) > 0)
373 return true;
374 }
375 return false;
376}
377
378static inline bool scsi_host_is_busy(struct Scsi_Host *shost)
379{
380 if (shost->can_queue > 0 &&
381 atomic_read(&shost->host_busy) >= shost->can_queue)
382 return true;
383 if (atomic_read(&shost->host_blocked) > 0)
384 return true;
385 if (shost->host_self_blocked)
386 return true;
387 return false;
388}
389
390static void scsi_starved_list_run(struct Scsi_Host *shost)
391{
392 LIST_HEAD(starved_list);
393 struct scsi_device *sdev;
394 unsigned long flags;
395
396 spin_lock_irqsave(shost->host_lock, flags);
397 list_splice_init(&shost->starved_list, &starved_list);
398
399 while (!list_empty(&starved_list)) {
400 struct request_queue *slq;
401
402 /*
403 * As long as shost is accepting commands and we have
404 * starved queues, call blk_run_queue. scsi_request_fn
405 * drops the queue_lock and can add us back to the
406 * starved_list.
407 *
408 * host_lock protects the starved_list and starved_entry.
409 * scsi_request_fn must get the host_lock before checking
410 * or modifying starved_list or starved_entry.
411 */
412 if (scsi_host_is_busy(shost))
413 break;
414
415 sdev = list_entry(starved_list.next,
416 struct scsi_device, starved_entry);
417 list_del_init(&sdev->starved_entry);
418 if (scsi_target_is_busy(scsi_target(sdev))) {
419 list_move_tail(&sdev->starved_entry,
420 &shost->starved_list);
421 continue;
422 }
423
424 /*
425 * Once we drop the host lock, a racing scsi_remove_device()
426 * call may remove the sdev from the starved list and destroy
427 * it and the queue. Mitigate by taking a reference to the
428 * queue and never touching the sdev again after we drop the
429 * host lock. Note: if __scsi_remove_device() invokes
430 * blk_cleanup_queue() before the queue is run from this
431 * function then blk_run_queue() will return immediately since
432 * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING.
433 */
434 slq = sdev->request_queue;
435 if (!blk_get_queue(slq))
436 continue;
437 spin_unlock_irqrestore(shost->host_lock, flags);
438
439 scsi_kick_queue(slq);
440 blk_put_queue(slq);
441
442 spin_lock_irqsave(shost->host_lock, flags);
443 }
444 /* put any unprocessed entries back */
445 list_splice(&starved_list, &shost->starved_list);
446 spin_unlock_irqrestore(shost->host_lock, flags);
447}
448
449/*
450 * Function: scsi_run_queue()
451 *
452 * Purpose: Select a proper request queue to serve next
453 *
454 * Arguments: q - last request's queue
455 *
456 * Returns: Nothing
457 *
458 * Notes: The previous command was completely finished, start
459 * a new one if possible.
460 */
461static void scsi_run_queue(struct request_queue *q)
462{
463 struct scsi_device *sdev = q->queuedata;
464
465 if (scsi_target(sdev)->single_lun)
466 scsi_single_lun_run(sdev);
467 if (!list_empty(&sdev->host->starved_list))
468 scsi_starved_list_run(sdev->host);
469
470 if (q->mq_ops)
471 blk_mq_start_stopped_hw_queues(q, false);
472 else
473 blk_run_queue(q);
474}
475
476void scsi_requeue_run_queue(struct work_struct *work)
477{
478 struct scsi_device *sdev;
479 struct request_queue *q;
480
481 sdev = container_of(work, struct scsi_device, requeue_work);
482 q = sdev->request_queue;
483 scsi_run_queue(q);
484}
485
486/*
487 * Function: scsi_requeue_command()
488 *
489 * Purpose: Handle post-processing of completed commands.
490 *
491 * Arguments: q - queue to operate on
492 * cmd - command that may need to be requeued.
493 *
494 * Returns: Nothing
495 *
496 * Notes: After command completion, there may be blocks left
497 * over which weren't finished by the previous command
498 * this can be for a number of reasons - the main one is
499 * I/O errors in the middle of the request, in which case
500 * we need to request the blocks that come after the bad
501 * sector.
502 * Notes: Upon return, cmd is a stale pointer.
503 */
504static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd)
505{
506 struct scsi_device *sdev = cmd->device;
507 struct request *req = cmd->request;
508 unsigned long flags;
509
510 spin_lock_irqsave(q->queue_lock, flags);
511 blk_unprep_request(req);
512 req->special = NULL;
513 scsi_put_command(cmd);
514 blk_requeue_request(q, req);
515 spin_unlock_irqrestore(q->queue_lock, flags);
516
517 scsi_run_queue(q);
518
519 put_device(&sdev->sdev_gendev);
520}
521
522void scsi_run_host_queues(struct Scsi_Host *shost)
523{
524 struct scsi_device *sdev;
525
526 shost_for_each_device(sdev, shost)
527 scsi_run_queue(sdev->request_queue);
528}
529
530static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
531{
532 if (cmd->request->cmd_type == REQ_TYPE_FS) {
533 struct scsi_driver *drv = scsi_cmd_to_driver(cmd);
534
535 if (drv->uninit_command)
536 drv->uninit_command(cmd);
537 }
538}
539
540static void scsi_mq_free_sgtables(struct scsi_cmnd *cmd)
541{
542 struct scsi_data_buffer *sdb;
543
544 if (cmd->sdb.table.nents)
545 sg_free_table_chained(&cmd->sdb.table, true);
546 if (cmd->request->next_rq) {
547 sdb = cmd->request->next_rq->special;
548 if (sdb)
549 sg_free_table_chained(&sdb->table, true);
550 }
551 if (scsi_prot_sg_count(cmd))
552 sg_free_table_chained(&cmd->prot_sdb->table, true);
553}
554
555static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
556{
557 struct scsi_device *sdev = cmd->device;
558 struct Scsi_Host *shost = sdev->host;
559 unsigned long flags;
560
561 scsi_mq_free_sgtables(cmd);
562 scsi_uninit_cmd(cmd);
563
564 if (shost->use_cmd_list) {
565 BUG_ON(list_empty(&cmd->list));
566 spin_lock_irqsave(&sdev->list_lock, flags);
567 list_del_init(&cmd->list);
568 spin_unlock_irqrestore(&sdev->list_lock, flags);
569 }
570}
571
572/*
573 * Function: scsi_release_buffers()
574 *
575 * Purpose: Free resources allocate for a scsi_command.
576 *
577 * Arguments: cmd - command that we are bailing.
578 *
579 * Lock status: Assumed that no lock is held upon entry.
580 *
581 * Returns: Nothing
582 *
583 * Notes: In the event that an upper level driver rejects a
584 * command, we must release resources allocated during
585 * the __init_io() function. Primarily this would involve
586 * the scatter-gather table.
587 */
588static void scsi_release_buffers(struct scsi_cmnd *cmd)
589{
590 if (cmd->sdb.table.nents)
591 sg_free_table_chained(&cmd->sdb.table, false);
592
593 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
594
595 if (scsi_prot_sg_count(cmd))
596 sg_free_table_chained(&cmd->prot_sdb->table, false);
597}
598
599static void scsi_release_bidi_buffers(struct scsi_cmnd *cmd)
600{
601 struct scsi_data_buffer *bidi_sdb = cmd->request->next_rq->special;
602
603 sg_free_table_chained(&bidi_sdb->table, false);
604 kmem_cache_free(scsi_sdb_cache, bidi_sdb);
605 cmd->request->next_rq->special = NULL;
606}
607
608static bool scsi_end_request(struct request *req, int error,
609 unsigned int bytes, unsigned int bidi_bytes)
610{
611 struct scsi_cmnd *cmd = req->special;
612 struct scsi_device *sdev = cmd->device;
613 struct request_queue *q = sdev->request_queue;
614
615 if (blk_update_request(req, error, bytes))
616 return true;
617
618 /* Bidi request must be completed as a whole */
619 if (unlikely(bidi_bytes) &&
620 blk_update_request(req->next_rq, error, bidi_bytes))
621 return true;
622
623 if (blk_queue_add_random(q))
624 add_disk_randomness(req->rq_disk);
625
626 if (req->mq_ctx) {
627 /*
628 * In the MQ case the command gets freed by __blk_mq_end_request,
629 * so we have to do all cleanup that depends on it earlier.
630 *
631 * We also can't kick the queues from irq context, so we
632 * will have to defer it to a workqueue.
633 */
634 scsi_mq_uninit_cmd(cmd);
635
636 __blk_mq_end_request(req, error);
637
638 if (scsi_target(sdev)->single_lun ||
639 !list_empty(&sdev->host->starved_list))
640 kblockd_schedule_work(&sdev->requeue_work);
641 else
642 blk_mq_start_stopped_hw_queues(q, true);
643 } else {
644 unsigned long flags;
645
646 if (bidi_bytes)
647 scsi_release_bidi_buffers(cmd);
648
649 spin_lock_irqsave(q->queue_lock, flags);
650 blk_finish_request(req, error);
651 spin_unlock_irqrestore(q->queue_lock, flags);
652
653 scsi_release_buffers(cmd);
654
655 scsi_put_command(cmd);
656 scsi_run_queue(q);
657 }
658
659 put_device(&sdev->sdev_gendev);
660 return false;
661}
662
663/**
664 * __scsi_error_from_host_byte - translate SCSI error code into errno
665 * @cmd: SCSI command (unused)
666 * @result: scsi error code
667 *
668 * Translate SCSI error code into standard UNIX errno.
669 * Return values:
670 * -ENOLINK temporary transport failure
671 * -EREMOTEIO permanent target failure, do not retry
672 * -EBADE permanent nexus failure, retry on other path
673 * -ENOSPC No write space available
674 * -ENODATA Medium error
675 * -EIO unspecified I/O error
676 */
677static int __scsi_error_from_host_byte(struct scsi_cmnd *cmd, int result)
678{
679 int error = 0;
680
681 switch(host_byte(result)) {
682 case DID_TRANSPORT_FAILFAST:
683 error = -ENOLINK;
684 break;
685 case DID_TARGET_FAILURE:
686 set_host_byte(cmd, DID_OK);
687 error = -EREMOTEIO;
688 break;
689 case DID_NEXUS_FAILURE:
690 set_host_byte(cmd, DID_OK);
691 error = -EBADE;
692 break;
693 case DID_ALLOC_FAILURE:
694 set_host_byte(cmd, DID_OK);
695 error = -ENOSPC;
696 break;
697 case DID_MEDIUM_ERROR:
698 set_host_byte(cmd, DID_OK);
699 error = -ENODATA;
700 break;
701 default:
702 error = -EIO;
703 break;
704 }
705
706 return error;
707}
708
709/*
710 * Function: scsi_io_completion()
711 *
712 * Purpose: Completion processing for block device I/O requests.
713 *
714 * Arguments: cmd - command that is finished.
715 *
716 * Lock status: Assumed that no lock is held upon entry.
717 *
718 * Returns: Nothing
719 *
720 * Notes: We will finish off the specified number of sectors. If we
721 * are done, the command block will be released and the queue
722 * function will be goosed. If we are not done then we have to
723 * figure out what to do next:
724 *
725 * a) We can call scsi_requeue_command(). The request
726 * will be unprepared and put back on the queue. Then
727 * a new command will be created for it. This should
728 * be used if we made forward progress, or if we want
729 * to switch from READ(10) to READ(6) for example.
730 *
731 * b) We can call __scsi_queue_insert(). The request will
732 * be put back on the queue and retried using the same
733 * command as before, possibly after a delay.
734 *
735 * c) We can call scsi_end_request() with -EIO to fail
736 * the remainder of the request.
737 */
738void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
739{
740 int result = cmd->result;
741 struct request_queue *q = cmd->device->request_queue;
742 struct request *req = cmd->request;
743 int error = 0;
744 struct scsi_sense_hdr sshdr;
745 bool sense_valid = false;
746 int sense_deferred = 0, level = 0;
747 enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,
748 ACTION_DELAYED_RETRY} action;
749 unsigned long wait_for = (cmd->allowed + 1) * req->timeout;
750
751 if (result) {
752 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
753 if (sense_valid)
754 sense_deferred = scsi_sense_is_deferred(&sshdr);
755 }
756
757 if (req->cmd_type == REQ_TYPE_BLOCK_PC) { /* SG_IO ioctl from block level */
758 if (result) {
759 if (sense_valid && req->sense) {
760 /*
761 * SG_IO wants current and deferred errors
762 */
763 int len = 8 + cmd->sense_buffer[7];
764
765 if (len > SCSI_SENSE_BUFFERSIZE)
766 len = SCSI_SENSE_BUFFERSIZE;
767 memcpy(req->sense, cmd->sense_buffer, len);
768 req->sense_len = len;
769 }
770 if (!sense_deferred)
771 error = __scsi_error_from_host_byte(cmd, result);
772 }
773 /*
774 * __scsi_error_from_host_byte may have reset the host_byte
775 */
776 req->errors = cmd->result;
777
778 req->resid_len = scsi_get_resid(cmd);
779
780 if (scsi_bidi_cmnd(cmd)) {
781 /*
782 * Bidi commands Must be complete as a whole,
783 * both sides at once.
784 */
785 req->next_rq->resid_len = scsi_in(cmd)->resid;
786 if (scsi_end_request(req, 0, blk_rq_bytes(req),
787 blk_rq_bytes(req->next_rq)))
788 BUG();
789 return;
790 }
791 } else if (blk_rq_bytes(req) == 0 && result && !sense_deferred) {
792 /*
793 * Certain non BLOCK_PC requests are commands that don't
794 * actually transfer anything (FLUSH), so cannot use
795 * good_bytes != blk_rq_bytes(req) as the signal for an error.
796 * This sets the error explicitly for the problem case.
797 */
798 error = __scsi_error_from_host_byte(cmd, result);
799 }
800
801 /* no bidi support for !REQ_TYPE_BLOCK_PC yet */
802 BUG_ON(blk_bidi_rq(req));
803
804 /*
805 * Next deal with any sectors which we were able to correctly
806 * handle.
807 */
808 SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd,
809 "%u sectors total, %d bytes done.\n",
810 blk_rq_sectors(req), good_bytes));
811
812 /*
813 * Recovered errors need reporting, but they're always treated
814 * as success, so fiddle the result code here. For BLOCK_PC
815 * we already took a copy of the original into rq->errors which
816 * is what gets returned to the user
817 */
818 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
819 /* if ATA PASS-THROUGH INFORMATION AVAILABLE skip
820 * print since caller wants ATA registers. Only occurs on
821 * SCSI ATA PASS_THROUGH commands when CK_COND=1
822 */
823 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
824 ;
825 else if (!(req->rq_flags & RQF_QUIET))
826 scsi_print_sense(cmd);
827 result = 0;
828 /* BLOCK_PC may have set error */
829 error = 0;
830 }
831
832 /*
833 * special case: failed zero length commands always need to
834 * drop down into the retry code. Otherwise, if we finished
835 * all bytes in the request we are done now.
836 */
837 if (!(blk_rq_bytes(req) == 0 && error) &&
838 !scsi_end_request(req, error, good_bytes, 0))
839 return;
840
841 /*
842 * Kill remainder if no retrys.
843 */
844 if (error && scsi_noretry_cmd(cmd)) {
845 if (scsi_end_request(req, error, blk_rq_bytes(req), 0))
846 BUG();
847 return;
848 }
849
850 /*
851 * If there had been no error, but we have leftover bytes in the
852 * requeues just queue the command up again.
853 */
854 if (result == 0)
855 goto requeue;
856
857 error = __scsi_error_from_host_byte(cmd, result);
858
859 if (host_byte(result) == DID_RESET) {
860 /* Third party bus reset or reset for error recovery
861 * reasons. Just retry the command and see what
862 * happens.
863 */
864 action = ACTION_RETRY;
865 } else if (sense_valid && !sense_deferred) {
866 switch (sshdr.sense_key) {
867 case UNIT_ATTENTION:
868 if (cmd->device->removable) {
869 /* Detected disc change. Set a bit
870 * and quietly refuse further access.
871 */
872 cmd->device->changed = 1;
873 action = ACTION_FAIL;
874 } else {
875 /* Must have been a power glitch, or a
876 * bus reset. Could not have been a
877 * media change, so we just retry the
878 * command and see what happens.
879 */
880 action = ACTION_RETRY;
881 }
882 break;
883 case ILLEGAL_REQUEST:
884 /* If we had an ILLEGAL REQUEST returned, then
885 * we may have performed an unsupported
886 * command. The only thing this should be
887 * would be a ten byte read where only a six
888 * byte read was supported. Also, on a system
889 * where READ CAPACITY failed, we may have
890 * read past the end of the disk.
891 */
892 if ((cmd->device->use_10_for_rw &&
893 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
894 (cmd->cmnd[0] == READ_10 ||
895 cmd->cmnd[0] == WRITE_10)) {
896 /* This will issue a new 6-byte command. */
897 cmd->device->use_10_for_rw = 0;
898 action = ACTION_REPREP;
899 } else if (sshdr.asc == 0x10) /* DIX */ {
900 action = ACTION_FAIL;
901 error = -EILSEQ;
902 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
903 } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
904 action = ACTION_FAIL;
905 error = -EREMOTEIO;
906 } else
907 action = ACTION_FAIL;
908 break;
909 case ABORTED_COMMAND:
910 action = ACTION_FAIL;
911 if (sshdr.asc == 0x10) /* DIF */
912 error = -EILSEQ;
913 break;
914 case NOT_READY:
915 /* If the device is in the process of becoming
916 * ready, or has a temporary blockage, retry.
917 */
918 if (sshdr.asc == 0x04) {
919 switch (sshdr.ascq) {
920 case 0x01: /* becoming ready */
921 case 0x04: /* format in progress */
922 case 0x05: /* rebuild in progress */
923 case 0x06: /* recalculation in progress */
924 case 0x07: /* operation in progress */
925 case 0x08: /* Long write in progress */
926 case 0x09: /* self test in progress */
927 case 0x14: /* space allocation in progress */
928 action = ACTION_DELAYED_RETRY;
929 break;
930 default:
931 action = ACTION_FAIL;
932 break;
933 }
934 } else
935 action = ACTION_FAIL;
936 break;
937 case VOLUME_OVERFLOW:
938 /* See SSC3rXX or current. */
939 action = ACTION_FAIL;
940 break;
941 default:
942 action = ACTION_FAIL;
943 break;
944 }
945 } else
946 action = ACTION_FAIL;
947
948 if (action != ACTION_FAIL &&
949 time_before(cmd->jiffies_at_alloc + wait_for, jiffies))
950 action = ACTION_FAIL;
951
952 switch (action) {
953 case ACTION_FAIL:
954 /* Give up and fail the remainder of the request */
955 if (!(req->rq_flags & RQF_QUIET)) {
956 static DEFINE_RATELIMIT_STATE(_rs,
957 DEFAULT_RATELIMIT_INTERVAL,
958 DEFAULT_RATELIMIT_BURST);
959
960 if (unlikely(scsi_logging_level))
961 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
962 SCSI_LOG_MLCOMPLETE_BITS);
963
964 /*
965 * if logging is enabled the failure will be printed
966 * in scsi_log_completion(), so avoid duplicate messages
967 */
968 if (!level && __ratelimit(&_rs)) {
969 scsi_print_result(cmd, NULL, FAILED);
970 if (driver_byte(result) & DRIVER_SENSE)
971 scsi_print_sense(cmd);
972 scsi_print_command(cmd);
973 }
974 }
975 if (!scsi_end_request(req, error, blk_rq_err_bytes(req), 0))
976 return;
977 /*FALLTHRU*/
978 case ACTION_REPREP:
979 requeue:
980 /* Unprep the request and put it back at the head of the queue.
981 * A new command will be prepared and issued.
982 */
983 if (q->mq_ops) {
984 cmd->request->rq_flags &= ~RQF_DONTPREP;
985 scsi_mq_uninit_cmd(cmd);
986 scsi_mq_requeue_cmd(cmd);
987 } else {
988 scsi_release_buffers(cmd);
989 scsi_requeue_command(q, cmd);
990 }
991 break;
992 case ACTION_RETRY:
993 /* Retry the same command immediately */
994 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, 0);
995 break;
996 case ACTION_DELAYED_RETRY:
997 /* Retry the same command after a delay */
998 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, 0);
999 break;
1000 }
1001}
1002
1003static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb)
1004{
1005 int count;
1006
1007 /*
1008 * If sg table allocation fails, requeue request later.
1009 */
1010 if (unlikely(sg_alloc_table_chained(&sdb->table,
1011 blk_rq_nr_phys_segments(req), sdb->table.sgl)))
1012 return BLKPREP_DEFER;
1013
1014 /*
1015 * Next, walk the list, and fill in the addresses and sizes of
1016 * each segment.
1017 */
1018 count = blk_rq_map_sg(req->q, req, sdb->table.sgl);
1019 BUG_ON(count > sdb->table.nents);
1020 sdb->table.nents = count;
1021 sdb->length = blk_rq_payload_bytes(req);
1022 return BLKPREP_OK;
1023}
1024
1025/*
1026 * Function: scsi_init_io()
1027 *
1028 * Purpose: SCSI I/O initialize function.
1029 *
1030 * Arguments: cmd - Command descriptor we wish to initialize
1031 *
1032 * Returns: 0 on success
1033 * BLKPREP_DEFER if the failure is retryable
1034 * BLKPREP_KILL if the failure is fatal
1035 */
1036int scsi_init_io(struct scsi_cmnd *cmd)
1037{
1038 struct scsi_device *sdev = cmd->device;
1039 struct request *rq = cmd->request;
1040 bool is_mq = (rq->mq_ctx != NULL);
1041 int error;
1042
1043 if (WARN_ON_ONCE(!blk_rq_nr_phys_segments(rq)))
1044 return -EINVAL;
1045
1046 error = scsi_init_sgtable(rq, &cmd->sdb);
1047 if (error)
1048 goto err_exit;
1049
1050 if (blk_bidi_rq(rq)) {
1051 if (!rq->q->mq_ops) {
1052 struct scsi_data_buffer *bidi_sdb =
1053 kmem_cache_zalloc(scsi_sdb_cache, GFP_ATOMIC);
1054 if (!bidi_sdb) {
1055 error = BLKPREP_DEFER;
1056 goto err_exit;
1057 }
1058
1059 rq->next_rq->special = bidi_sdb;
1060 }
1061
1062 error = scsi_init_sgtable(rq->next_rq, rq->next_rq->special);
1063 if (error)
1064 goto err_exit;
1065 }
1066
1067 if (blk_integrity_rq(rq)) {
1068 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1069 int ivecs, count;
1070
1071 if (prot_sdb == NULL) {
1072 /*
1073 * This can happen if someone (e.g. multipath)
1074 * queues a command to a device on an adapter
1075 * that does not support DIX.
1076 */
1077 WARN_ON_ONCE(1);
1078 error = BLKPREP_KILL;
1079 goto err_exit;
1080 }
1081
1082 ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
1083
1084 if (sg_alloc_table_chained(&prot_sdb->table, ivecs,
1085 prot_sdb->table.sgl)) {
1086 error = BLKPREP_DEFER;
1087 goto err_exit;
1088 }
1089
1090 count = blk_rq_map_integrity_sg(rq->q, rq->bio,
1091 prot_sdb->table.sgl);
1092 BUG_ON(unlikely(count > ivecs));
1093 BUG_ON(unlikely(count > queue_max_integrity_segments(rq->q)));
1094
1095 cmd->prot_sdb = prot_sdb;
1096 cmd->prot_sdb->table.nents = count;
1097 }
1098
1099 return BLKPREP_OK;
1100err_exit:
1101 if (is_mq) {
1102 scsi_mq_free_sgtables(cmd);
1103 } else {
1104 scsi_release_buffers(cmd);
1105 cmd->request->special = NULL;
1106 scsi_put_command(cmd);
1107 put_device(&sdev->sdev_gendev);
1108 }
1109 return error;
1110}
1111EXPORT_SYMBOL(scsi_init_io);
1112
1113static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev,
1114 struct request *req)
1115{
1116 struct scsi_cmnd *cmd;
1117
1118 if (!req->special) {
1119 /* Bail if we can't get a reference to the device */
1120 if (!get_device(&sdev->sdev_gendev))
1121 return NULL;
1122
1123 cmd = scsi_get_command(sdev, GFP_ATOMIC);
1124 if (unlikely(!cmd)) {
1125 put_device(&sdev->sdev_gendev);
1126 return NULL;
1127 }
1128 req->special = cmd;
1129 } else {
1130 cmd = req->special;
1131 }
1132
1133 /* pull a tag out of the request if we have one */
1134 cmd->tag = req->tag;
1135 cmd->request = req;
1136
1137 cmd->cmnd = req->cmd;
1138 cmd->prot_op = SCSI_PROT_NORMAL;
1139
1140 return cmd;
1141}
1142
1143static int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
1144{
1145 struct scsi_cmnd *cmd = req->special;
1146
1147 /*
1148 * BLOCK_PC requests may transfer data, in which case they must
1149 * a bio attached to them. Or they might contain a SCSI command
1150 * that does not transfer data, in which case they may optionally
1151 * submit a request without an attached bio.
1152 */
1153 if (req->bio) {
1154 int ret = scsi_init_io(cmd);
1155 if (unlikely(ret))
1156 return ret;
1157 } else {
1158 BUG_ON(blk_rq_bytes(req));
1159
1160 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1161 }
1162
1163 cmd->cmd_len = req->cmd_len;
1164 cmd->transfersize = blk_rq_bytes(req);
1165 cmd->allowed = req->retries;
1166 return BLKPREP_OK;
1167}
1168
1169/*
1170 * Setup a REQ_TYPE_FS command. These are simple request from filesystems
1171 * that still need to be translated to SCSI CDBs from the ULD.
1172 */
1173static int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
1174{
1175 struct scsi_cmnd *cmd = req->special;
1176
1177 if (unlikely(sdev->handler && sdev->handler->prep_fn)) {
1178 int ret = sdev->handler->prep_fn(sdev, req);
1179 if (ret != BLKPREP_OK)
1180 return ret;
1181 }
1182
1183 memset(cmd->cmnd, 0, BLK_MAX_CDB);
1184 return scsi_cmd_to_driver(cmd)->init_command(cmd);
1185}
1186
1187static int scsi_setup_cmnd(struct scsi_device *sdev, struct request *req)
1188{
1189 struct scsi_cmnd *cmd = req->special;
1190
1191 if (!blk_rq_bytes(req))
1192 cmd->sc_data_direction = DMA_NONE;
1193 else if (rq_data_dir(req) == WRITE)
1194 cmd->sc_data_direction = DMA_TO_DEVICE;
1195 else
1196 cmd->sc_data_direction = DMA_FROM_DEVICE;
1197
1198 switch (req->cmd_type) {
1199 case REQ_TYPE_FS:
1200 return scsi_setup_fs_cmnd(sdev, req);
1201 case REQ_TYPE_BLOCK_PC:
1202 return scsi_setup_blk_pc_cmnd(sdev, req);
1203 default:
1204 return BLKPREP_KILL;
1205 }
1206}
1207
1208static int
1209scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
1210{
1211 int ret = BLKPREP_OK;
1212
1213 /*
1214 * If the device is not in running state we will reject some
1215 * or all commands.
1216 */
1217 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
1218 switch (sdev->sdev_state) {
1219 case SDEV_OFFLINE:
1220 case SDEV_TRANSPORT_OFFLINE:
1221 /*
1222 * If the device is offline we refuse to process any
1223 * commands. The device must be brought online
1224 * before trying any recovery commands.
1225 */
1226 sdev_printk(KERN_ERR, sdev,
1227 "rejecting I/O to offline device\n");
1228 ret = BLKPREP_KILL;
1229 break;
1230 case SDEV_DEL:
1231 /*
1232 * If the device is fully deleted, we refuse to
1233 * process any commands as well.
1234 */
1235 sdev_printk(KERN_ERR, sdev,
1236 "rejecting I/O to dead device\n");
1237 ret = BLKPREP_KILL;
1238 break;
1239 case SDEV_BLOCK:
1240 case SDEV_CREATED_BLOCK:
1241 ret = BLKPREP_DEFER;
1242 break;
1243 case SDEV_QUIESCE:
1244 /*
1245 * If the devices is blocked we defer normal commands.
1246 */
1247 if (!(req->rq_flags & RQF_PREEMPT))
1248 ret = BLKPREP_DEFER;
1249 break;
1250 default:
1251 /*
1252 * For any other not fully online state we only allow
1253 * special commands. In particular any user initiated
1254 * command is not allowed.
1255 */
1256 if (!(req->rq_flags & RQF_PREEMPT))
1257 ret = BLKPREP_KILL;
1258 break;
1259 }
1260 }
1261 return ret;
1262}
1263
1264static int
1265scsi_prep_return(struct request_queue *q, struct request *req, int ret)
1266{
1267 struct scsi_device *sdev = q->queuedata;
1268
1269 switch (ret) {
1270 case BLKPREP_KILL:
1271 case BLKPREP_INVALID:
1272 req->errors = DID_NO_CONNECT << 16;
1273 /* release the command and kill it */
1274 if (req->special) {
1275 struct scsi_cmnd *cmd = req->special;
1276 scsi_release_buffers(cmd);
1277 scsi_put_command(cmd);
1278 put_device(&sdev->sdev_gendev);
1279 req->special = NULL;
1280 }
1281 break;
1282 case BLKPREP_DEFER:
1283 /*
1284 * If we defer, the blk_peek_request() returns NULL, but the
1285 * queue must be restarted, so we schedule a callback to happen
1286 * shortly.
1287 */
1288 if (atomic_read(&sdev->device_busy) == 0)
1289 blk_delay_queue(q, SCSI_QUEUE_DELAY);
1290 break;
1291 default:
1292 req->rq_flags |= RQF_DONTPREP;
1293 }
1294
1295 return ret;
1296}
1297
1298static int scsi_prep_fn(struct request_queue *q, struct request *req)
1299{
1300 struct scsi_device *sdev = q->queuedata;
1301 struct scsi_cmnd *cmd;
1302 int ret;
1303
1304 ret = scsi_prep_state_check(sdev, req);
1305 if (ret != BLKPREP_OK)
1306 goto out;
1307
1308 cmd = scsi_get_cmd_from_req(sdev, req);
1309 if (unlikely(!cmd)) {
1310 ret = BLKPREP_DEFER;
1311 goto out;
1312 }
1313
1314 ret = scsi_setup_cmnd(sdev, req);
1315out:
1316 return scsi_prep_return(q, req, ret);
1317}
1318
1319static void scsi_unprep_fn(struct request_queue *q, struct request *req)
1320{
1321 scsi_uninit_cmd(req->special);
1322}
1323
1324/*
1325 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1326 * return 0.
1327 *
1328 * Called with the queue_lock held.
1329 */
1330static inline int scsi_dev_queue_ready(struct request_queue *q,
1331 struct scsi_device *sdev)
1332{
1333 unsigned int busy;
1334
1335 busy = atomic_inc_return(&sdev->device_busy) - 1;
1336 if (atomic_read(&sdev->device_blocked)) {
1337 if (busy)
1338 goto out_dec;
1339
1340 /*
1341 * unblock after device_blocked iterates to zero
1342 */
1343 if (atomic_dec_return(&sdev->device_blocked) > 0) {
1344 /*
1345 * For the MQ case we take care of this in the caller.
1346 */
1347 if (!q->mq_ops)
1348 blk_delay_queue(q, SCSI_QUEUE_DELAY);
1349 goto out_dec;
1350 }
1351 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev,
1352 "unblocking device at zero depth\n"));
1353 }
1354
1355 if (busy >= sdev->queue_depth)
1356 goto out_dec;
1357
1358 return 1;
1359out_dec:
1360 atomic_dec(&sdev->device_busy);
1361 return 0;
1362}
1363
1364/*
1365 * scsi_target_queue_ready: checks if there we can send commands to target
1366 * @sdev: scsi device on starget to check.
1367 */
1368static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1369 struct scsi_device *sdev)
1370{
1371 struct scsi_target *starget = scsi_target(sdev);
1372 unsigned int busy;
1373
1374 if (starget->single_lun) {
1375 spin_lock_irq(shost->host_lock);
1376 if (starget->starget_sdev_user &&
1377 starget->starget_sdev_user != sdev) {
1378 spin_unlock_irq(shost->host_lock);
1379 return 0;
1380 }
1381 starget->starget_sdev_user = sdev;
1382 spin_unlock_irq(shost->host_lock);
1383 }
1384
1385 if (starget->can_queue <= 0)
1386 return 1;
1387
1388 busy = atomic_inc_return(&starget->target_busy) - 1;
1389 if (atomic_read(&starget->target_blocked) > 0) {
1390 if (busy)
1391 goto starved;
1392
1393 /*
1394 * unblock after target_blocked iterates to zero
1395 */
1396 if (atomic_dec_return(&starget->target_blocked) > 0)
1397 goto out_dec;
1398
1399 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1400 "unblocking target at zero depth\n"));
1401 }
1402
1403 if (busy >= starget->can_queue)
1404 goto starved;
1405
1406 return 1;
1407
1408starved:
1409 spin_lock_irq(shost->host_lock);
1410 list_move_tail(&sdev->starved_entry, &shost->starved_list);
1411 spin_unlock_irq(shost->host_lock);
1412out_dec:
1413 if (starget->can_queue > 0)
1414 atomic_dec(&starget->target_busy);
1415 return 0;
1416}
1417
1418/*
1419 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1420 * return 0. We must end up running the queue again whenever 0 is
1421 * returned, else IO can hang.
1422 */
1423static inline int scsi_host_queue_ready(struct request_queue *q,
1424 struct Scsi_Host *shost,
1425 struct scsi_device *sdev)
1426{
1427 unsigned int busy;
1428
1429 if (scsi_host_in_recovery(shost))
1430 return 0;
1431
1432 busy = atomic_inc_return(&shost->host_busy) - 1;
1433 if (atomic_read(&shost->host_blocked) > 0) {
1434 if (busy)
1435 goto starved;
1436
1437 /*
1438 * unblock after host_blocked iterates to zero
1439 */
1440 if (atomic_dec_return(&shost->host_blocked) > 0)
1441 goto out_dec;
1442
1443 SCSI_LOG_MLQUEUE(3,
1444 shost_printk(KERN_INFO, shost,
1445 "unblocking host at zero depth\n"));
1446 }
1447
1448 if (shost->can_queue > 0 && busy >= shost->can_queue)
1449 goto starved;
1450 if (shost->host_self_blocked)
1451 goto starved;
1452
1453 /* We're OK to process the command, so we can't be starved */
1454 if (!list_empty(&sdev->starved_entry)) {
1455 spin_lock_irq(shost->host_lock);
1456 if (!list_empty(&sdev->starved_entry))
1457 list_del_init(&sdev->starved_entry);
1458 spin_unlock_irq(shost->host_lock);
1459 }
1460
1461 return 1;
1462
1463starved:
1464 spin_lock_irq(shost->host_lock);
1465 if (list_empty(&sdev->starved_entry))
1466 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1467 spin_unlock_irq(shost->host_lock);
1468out_dec:
1469 atomic_dec(&shost->host_busy);
1470 return 0;
1471}
1472
1473/*
1474 * Busy state exporting function for request stacking drivers.
1475 *
1476 * For efficiency, no lock is taken to check the busy state of
1477 * shost/starget/sdev, since the returned value is not guaranteed and
1478 * may be changed after request stacking drivers call the function,
1479 * regardless of taking lock or not.
1480 *
1481 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1482 * needs to return 'not busy'. Otherwise, request stacking drivers
1483 * may hold requests forever.
1484 */
1485static int scsi_lld_busy(struct request_queue *q)
1486{
1487 struct scsi_device *sdev = q->queuedata;
1488 struct Scsi_Host *shost;
1489
1490 if (blk_queue_dying(q))
1491 return 0;
1492
1493 shost = sdev->host;
1494
1495 /*
1496 * Ignore host/starget busy state.
1497 * Since block layer does not have a concept of fairness across
1498 * multiple queues, congestion of host/starget needs to be handled
1499 * in SCSI layer.
1500 */
1501 if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
1502 return 1;
1503
1504 return 0;
1505}
1506
1507/*
1508 * Kill a request for a dead device
1509 */
1510static void scsi_kill_request(struct request *req, struct request_queue *q)
1511{
1512 struct scsi_cmnd *cmd = req->special;
1513 struct scsi_device *sdev;
1514 struct scsi_target *starget;
1515 struct Scsi_Host *shost;
1516
1517 blk_start_request(req);
1518
1519 scmd_printk(KERN_INFO, cmd, "killing request\n");
1520
1521 sdev = cmd->device;
1522 starget = scsi_target(sdev);
1523 shost = sdev->host;
1524 scsi_init_cmd_errh(cmd);
1525 cmd->result = DID_NO_CONNECT << 16;
1526 atomic_inc(&cmd->device->iorequest_cnt);
1527
1528 /*
1529 * SCSI request completion path will do scsi_device_unbusy(),
1530 * bump busy counts. To bump the counters, we need to dance
1531 * with the locks as normal issue path does.
1532 */
1533 atomic_inc(&sdev->device_busy);
1534 atomic_inc(&shost->host_busy);
1535 if (starget->can_queue > 0)
1536 atomic_inc(&starget->target_busy);
1537
1538 blk_complete_request(req);
1539}
1540
1541static void scsi_softirq_done(struct request *rq)
1542{
1543 struct scsi_cmnd *cmd = rq->special;
1544 unsigned long wait_for = (cmd->allowed + 1) * rq->timeout;
1545 int disposition;
1546
1547 INIT_LIST_HEAD(&cmd->eh_entry);
1548
1549 atomic_inc(&cmd->device->iodone_cnt);
1550 if (cmd->result)
1551 atomic_inc(&cmd->device->ioerr_cnt);
1552
1553 disposition = scsi_decide_disposition(cmd);
1554 if (disposition != SUCCESS &&
1555 time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
1556 sdev_printk(KERN_ERR, cmd->device,
1557 "timing out command, waited %lus\n",
1558 wait_for/HZ);
1559 disposition = SUCCESS;
1560 }
1561
1562 scsi_log_completion(cmd, disposition);
1563
1564 switch (disposition) {
1565 case SUCCESS:
1566 scsi_finish_command(cmd);
1567 break;
1568 case NEEDS_RETRY:
1569 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
1570 break;
1571 case ADD_TO_MLQUEUE:
1572 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1573 break;
1574 default:
1575 if (!scsi_eh_scmd_add(cmd, 0))
1576 scsi_finish_command(cmd);
1577 }
1578}
1579
1580/**
1581 * scsi_dispatch_command - Dispatch a command to the low-level driver.
1582 * @cmd: command block we are dispatching.
1583 *
1584 * Return: nonzero return request was rejected and device's queue needs to be
1585 * plugged.
1586 */
1587static int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
1588{
1589 struct Scsi_Host *host = cmd->device->host;
1590 int rtn = 0;
1591
1592 atomic_inc(&cmd->device->iorequest_cnt);
1593
1594 /* check if the device is still usable */
1595 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
1596 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
1597 * returns an immediate error upwards, and signals
1598 * that the device is no longer present */
1599 cmd->result = DID_NO_CONNECT << 16;
1600 goto done;
1601 }
1602
1603 /* Check to see if the scsi lld made this device blocked. */
1604 if (unlikely(scsi_device_blocked(cmd->device))) {
1605 /*
1606 * in blocked state, the command is just put back on
1607 * the device queue. The suspend state has already
1608 * blocked the queue so future requests should not
1609 * occur until the device transitions out of the
1610 * suspend state.
1611 */
1612 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1613 "queuecommand : device blocked\n"));
1614 return SCSI_MLQUEUE_DEVICE_BUSY;
1615 }
1616
1617 /* Store the LUN value in cmnd, if needed. */
1618 if (cmd->device->lun_in_cdb)
1619 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
1620 (cmd->device->lun << 5 & 0xe0);
1621
1622 scsi_log_send(cmd);
1623
1624 /*
1625 * Before we queue this command, check if the command
1626 * length exceeds what the host adapter can handle.
1627 */
1628 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
1629 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1630 "queuecommand : command too long. "
1631 "cdb_size=%d host->max_cmd_len=%d\n",
1632 cmd->cmd_len, cmd->device->host->max_cmd_len));
1633 cmd->result = (DID_ABORT << 16);
1634 goto done;
1635 }
1636
1637 if (unlikely(host->shost_state == SHOST_DEL)) {
1638 cmd->result = (DID_NO_CONNECT << 16);
1639 goto done;
1640
1641 }
1642
1643 trace_scsi_dispatch_cmd_start(cmd);
1644 rtn = host->hostt->queuecommand(host, cmd);
1645 if (rtn) {
1646 trace_scsi_dispatch_cmd_error(cmd, rtn);
1647 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
1648 rtn != SCSI_MLQUEUE_TARGET_BUSY)
1649 rtn = SCSI_MLQUEUE_HOST_BUSY;
1650
1651 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1652 "queuecommand : request rejected\n"));
1653 }
1654
1655 return rtn;
1656 done:
1657 cmd->scsi_done(cmd);
1658 return 0;
1659}
1660
1661/**
1662 * scsi_done - Invoke completion on finished SCSI command.
1663 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
1664 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
1665 *
1666 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
1667 * which regains ownership of the SCSI command (de facto) from a LLDD, and
1668 * calls blk_complete_request() for further processing.
1669 *
1670 * This function is interrupt context safe.
1671 */
1672static void scsi_done(struct scsi_cmnd *cmd)
1673{
1674 trace_scsi_dispatch_cmd_done(cmd);
1675 blk_complete_request(cmd->request);
1676}
1677
1678/*
1679 * Function: scsi_request_fn()
1680 *
1681 * Purpose: Main strategy routine for SCSI.
1682 *
1683 * Arguments: q - Pointer to actual queue.
1684 *
1685 * Returns: Nothing
1686 *
1687 * Lock status: IO request lock assumed to be held when called.
1688 */
1689static void scsi_request_fn(struct request_queue *q)
1690 __releases(q->queue_lock)
1691 __acquires(q->queue_lock)
1692{
1693 struct scsi_device *sdev = q->queuedata;
1694 struct Scsi_Host *shost;
1695 struct scsi_cmnd *cmd;
1696 struct request *req;
1697
1698 /*
1699 * To start with, we keep looping until the queue is empty, or until
1700 * the host is no longer able to accept any more requests.
1701 */
1702 shost = sdev->host;
1703 for (;;) {
1704 int rtn;
1705 /*
1706 * get next queueable request. We do this early to make sure
1707 * that the request is fully prepared even if we cannot
1708 * accept it.
1709 */
1710 req = blk_peek_request(q);
1711 if (!req)
1712 break;
1713
1714 if (unlikely(!scsi_device_online(sdev))) {
1715 sdev_printk(KERN_ERR, sdev,
1716 "rejecting I/O to offline device\n");
1717 scsi_kill_request(req, q);
1718 continue;
1719 }
1720
1721 if (!scsi_dev_queue_ready(q, sdev))
1722 break;
1723
1724 /*
1725 * Remove the request from the request list.
1726 */
1727 if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req)))
1728 blk_start_request(req);
1729
1730 spin_unlock_irq(q->queue_lock);
1731 cmd = req->special;
1732 if (unlikely(cmd == NULL)) {
1733 printk(KERN_CRIT "impossible request in %s.\n"
1734 "please mail a stack trace to "
1735 "linux-scsi@vger.kernel.org\n",
1736 __func__);
1737 blk_dump_rq_flags(req, "foo");
1738 BUG();
1739 }
1740
1741 /*
1742 * We hit this when the driver is using a host wide
1743 * tag map. For device level tag maps the queue_depth check
1744 * in the device ready fn would prevent us from trying
1745 * to allocate a tag. Since the map is a shared host resource
1746 * we add the dev to the starved list so it eventually gets
1747 * a run when a tag is freed.
1748 */
1749 if (blk_queue_tagged(q) && !(req->rq_flags & RQF_QUEUED)) {
1750 spin_lock_irq(shost->host_lock);
1751 if (list_empty(&sdev->starved_entry))
1752 list_add_tail(&sdev->starved_entry,
1753 &shost->starved_list);
1754 spin_unlock_irq(shost->host_lock);
1755 goto not_ready;
1756 }
1757
1758 if (!scsi_target_queue_ready(shost, sdev))
1759 goto not_ready;
1760
1761 if (!scsi_host_queue_ready(q, shost, sdev))
1762 goto host_not_ready;
1763
1764 if (sdev->simple_tags)
1765 cmd->flags |= SCMD_TAGGED;
1766 else
1767 cmd->flags &= ~SCMD_TAGGED;
1768
1769 /*
1770 * Finally, initialize any error handling parameters, and set up
1771 * the timers for timeouts.
1772 */
1773 scsi_init_cmd_errh(cmd);
1774
1775 /*
1776 * Dispatch the command to the low-level driver.
1777 */
1778 cmd->scsi_done = scsi_done;
1779 rtn = scsi_dispatch_cmd(cmd);
1780 if (rtn) {
1781 scsi_queue_insert(cmd, rtn);
1782 spin_lock_irq(q->queue_lock);
1783 goto out_delay;
1784 }
1785 spin_lock_irq(q->queue_lock);
1786 }
1787
1788 return;
1789
1790 host_not_ready:
1791 if (scsi_target(sdev)->can_queue > 0)
1792 atomic_dec(&scsi_target(sdev)->target_busy);
1793 not_ready:
1794 /*
1795 * lock q, handle tag, requeue req, and decrement device_busy. We
1796 * must return with queue_lock held.
1797 *
1798 * Decrementing device_busy without checking it is OK, as all such
1799 * cases (host limits or settings) should run the queue at some
1800 * later time.
1801 */
1802 spin_lock_irq(q->queue_lock);
1803 blk_requeue_request(q, req);
1804 atomic_dec(&sdev->device_busy);
1805out_delay:
1806 if (!atomic_read(&sdev->device_busy) && !scsi_device_blocked(sdev))
1807 blk_delay_queue(q, SCSI_QUEUE_DELAY);
1808}
1809
1810static inline int prep_to_mq(int ret)
1811{
1812 switch (ret) {
1813 case BLKPREP_OK:
1814 return BLK_MQ_RQ_QUEUE_OK;
1815 case BLKPREP_DEFER:
1816 return BLK_MQ_RQ_QUEUE_BUSY;
1817 default:
1818 return BLK_MQ_RQ_QUEUE_ERROR;
1819 }
1820}
1821
1822static int scsi_mq_prep_fn(struct request *req)
1823{
1824 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1825 struct scsi_device *sdev = req->q->queuedata;
1826 struct Scsi_Host *shost = sdev->host;
1827 unsigned char *sense_buf = cmd->sense_buffer;
1828 struct scatterlist *sg;
1829
1830 memset(cmd, 0, sizeof(struct scsi_cmnd));
1831
1832 req->special = cmd;
1833
1834 cmd->request = req;
1835 cmd->device = sdev;
1836 cmd->sense_buffer = sense_buf;
1837
1838 cmd->tag = req->tag;
1839
1840 cmd->cmnd = req->cmd;
1841 cmd->prot_op = SCSI_PROT_NORMAL;
1842
1843 INIT_LIST_HEAD(&cmd->list);
1844 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
1845 cmd->jiffies_at_alloc = jiffies;
1846
1847 if (shost->use_cmd_list) {
1848 spin_lock_irq(&sdev->list_lock);
1849 list_add_tail(&cmd->list, &sdev->cmd_list);
1850 spin_unlock_irq(&sdev->list_lock);
1851 }
1852
1853 sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
1854 cmd->sdb.table.sgl = sg;
1855
1856 if (scsi_host_get_prot(shost)) {
1857 cmd->prot_sdb = (void *)sg +
1858 min_t(unsigned int,
1859 shost->sg_tablesize, SG_CHUNK_SIZE) *
1860 sizeof(struct scatterlist);
1861 memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer));
1862
1863 cmd->prot_sdb->table.sgl =
1864 (struct scatterlist *)(cmd->prot_sdb + 1);
1865 }
1866
1867 if (blk_bidi_rq(req)) {
1868 struct request *next_rq = req->next_rq;
1869 struct scsi_data_buffer *bidi_sdb = blk_mq_rq_to_pdu(next_rq);
1870
1871 memset(bidi_sdb, 0, sizeof(struct scsi_data_buffer));
1872 bidi_sdb->table.sgl =
1873 (struct scatterlist *)(bidi_sdb + 1);
1874
1875 next_rq->special = bidi_sdb;
1876 }
1877
1878 blk_mq_start_request(req);
1879
1880 return scsi_setup_cmnd(sdev, req);
1881}
1882
1883static void scsi_mq_done(struct scsi_cmnd *cmd)
1884{
1885 trace_scsi_dispatch_cmd_done(cmd);
1886 blk_mq_complete_request(cmd->request, cmd->request->errors);
1887}
1888
1889static int scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
1890 const struct blk_mq_queue_data *bd)
1891{
1892 struct request *req = bd->rq;
1893 struct request_queue *q = req->q;
1894 struct scsi_device *sdev = q->queuedata;
1895 struct Scsi_Host *shost = sdev->host;
1896 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1897 int ret;
1898 int reason;
1899
1900 ret = prep_to_mq(scsi_prep_state_check(sdev, req));
1901 if (ret != BLK_MQ_RQ_QUEUE_OK)
1902 goto out;
1903
1904 ret = BLK_MQ_RQ_QUEUE_BUSY;
1905 if (!get_device(&sdev->sdev_gendev))
1906 goto out;
1907
1908 if (!scsi_dev_queue_ready(q, sdev))
1909 goto out_put_device;
1910 if (!scsi_target_queue_ready(shost, sdev))
1911 goto out_dec_device_busy;
1912 if (!scsi_host_queue_ready(q, shost, sdev))
1913 goto out_dec_target_busy;
1914
1915
1916 if (!(req->rq_flags & RQF_DONTPREP)) {
1917 ret = prep_to_mq(scsi_mq_prep_fn(req));
1918 if (ret != BLK_MQ_RQ_QUEUE_OK)
1919 goto out_dec_host_busy;
1920 req->rq_flags |= RQF_DONTPREP;
1921 } else {
1922 blk_mq_start_request(req);
1923 }
1924
1925 if (sdev->simple_tags)
1926 cmd->flags |= SCMD_TAGGED;
1927 else
1928 cmd->flags &= ~SCMD_TAGGED;
1929
1930 scsi_init_cmd_errh(cmd);
1931 cmd->scsi_done = scsi_mq_done;
1932
1933 reason = scsi_dispatch_cmd(cmd);
1934 if (reason) {
1935 scsi_set_blocked(cmd, reason);
1936 ret = BLK_MQ_RQ_QUEUE_BUSY;
1937 goto out_dec_host_busy;
1938 }
1939
1940 return BLK_MQ_RQ_QUEUE_OK;
1941
1942out_dec_host_busy:
1943 atomic_dec(&shost->host_busy);
1944out_dec_target_busy:
1945 if (scsi_target(sdev)->can_queue > 0)
1946 atomic_dec(&scsi_target(sdev)->target_busy);
1947out_dec_device_busy:
1948 atomic_dec(&sdev->device_busy);
1949out_put_device:
1950 put_device(&sdev->sdev_gendev);
1951out:
1952 switch (ret) {
1953 case BLK_MQ_RQ_QUEUE_BUSY:
1954 if (atomic_read(&sdev->device_busy) == 0 &&
1955 !scsi_device_blocked(sdev))
1956 blk_mq_delay_queue(hctx, SCSI_QUEUE_DELAY);
1957 break;
1958 case BLK_MQ_RQ_QUEUE_ERROR:
1959 /*
1960 * Make sure to release all allocated ressources when
1961 * we hit an error, as we will never see this command
1962 * again.
1963 */
1964 if (req->rq_flags & RQF_DONTPREP)
1965 scsi_mq_uninit_cmd(cmd);
1966 break;
1967 default:
1968 break;
1969 }
1970 return ret;
1971}
1972
1973static enum blk_eh_timer_return scsi_timeout(struct request *req,
1974 bool reserved)
1975{
1976 if (reserved)
1977 return BLK_EH_RESET_TIMER;
1978 return scsi_times_out(req);
1979}
1980
1981static int scsi_init_request(void *data, struct request *rq,
1982 unsigned int hctx_idx, unsigned int request_idx,
1983 unsigned int numa_node)
1984{
1985 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1986
1987 cmd->sense_buffer = kzalloc_node(SCSI_SENSE_BUFFERSIZE, GFP_KERNEL,
1988 numa_node);
1989 if (!cmd->sense_buffer)
1990 return -ENOMEM;
1991 return 0;
1992}
1993
1994static void scsi_exit_request(void *data, struct request *rq,
1995 unsigned int hctx_idx, unsigned int request_idx)
1996{
1997 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1998
1999 kfree(cmd->sense_buffer);
2000}
2001
2002static int scsi_map_queues(struct blk_mq_tag_set *set)
2003{
2004 struct Scsi_Host *shost = container_of(set, struct Scsi_Host, tag_set);
2005
2006 if (shost->hostt->map_queues)
2007 return shost->hostt->map_queues(shost);
2008 return blk_mq_map_queues(set);
2009}
2010
2011static u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost)
2012{
2013 struct device *host_dev;
2014 u64 bounce_limit = 0xffffffff;
2015
2016 if (shost->unchecked_isa_dma)
2017 return BLK_BOUNCE_ISA;
2018 /*
2019 * Platforms with virtual-DMA translation
2020 * hardware have no practical limit.
2021 */
2022 if (!PCI_DMA_BUS_IS_PHYS)
2023 return BLK_BOUNCE_ANY;
2024
2025 host_dev = scsi_get_device(shost);
2026 if (host_dev && host_dev->dma_mask)
2027 bounce_limit = (u64)dma_max_pfn(host_dev) << PAGE_SHIFT;
2028
2029 return bounce_limit;
2030}
2031
2032static void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
2033{
2034 struct device *dev = shost->dma_dev;
2035
2036 /*
2037 * this limit is imposed by hardware restrictions
2038 */
2039 blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
2040 SG_MAX_SEGMENTS));
2041
2042 if (scsi_host_prot_dma(shost)) {
2043 shost->sg_prot_tablesize =
2044 min_not_zero(shost->sg_prot_tablesize,
2045 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
2046 BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
2047 blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
2048 }
2049
2050 blk_queue_max_hw_sectors(q, shost->max_sectors);
2051 blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost));
2052 blk_queue_segment_boundary(q, shost->dma_boundary);
2053 dma_set_seg_boundary(dev, shost->dma_boundary);
2054
2055 blk_queue_max_segment_size(q, dma_get_max_seg_size(dev));
2056
2057 if (!shost->use_clustering)
2058 q->limits.cluster = 0;
2059
2060 /*
2061 * set a reasonable default alignment on word boundaries: the
2062 * host and device may alter it using
2063 * blk_queue_update_dma_alignment() later.
2064 */
2065 blk_queue_dma_alignment(q, 0x03);
2066}
2067
2068struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost,
2069 request_fn_proc *request_fn)
2070{
2071 struct request_queue *q;
2072
2073 q = blk_init_queue(request_fn, NULL);
2074 if (!q)
2075 return NULL;
2076 __scsi_init_queue(shost, q);
2077 return q;
2078}
2079EXPORT_SYMBOL(__scsi_alloc_queue);
2080
2081struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
2082{
2083 struct request_queue *q;
2084
2085 q = __scsi_alloc_queue(sdev->host, scsi_request_fn);
2086 if (!q)
2087 return NULL;
2088
2089 blk_queue_prep_rq(q, scsi_prep_fn);
2090 blk_queue_unprep_rq(q, scsi_unprep_fn);
2091 blk_queue_softirq_done(q, scsi_softirq_done);
2092 blk_queue_rq_timed_out(q, scsi_times_out);
2093 blk_queue_lld_busy(q, scsi_lld_busy);
2094 return q;
2095}
2096
2097static struct blk_mq_ops scsi_mq_ops = {
2098 .queue_rq = scsi_queue_rq,
2099 .complete = scsi_softirq_done,
2100 .timeout = scsi_timeout,
2101 .init_request = scsi_init_request,
2102 .exit_request = scsi_exit_request,
2103 .map_queues = scsi_map_queues,
2104};
2105
2106struct request_queue *scsi_mq_alloc_queue(struct scsi_device *sdev)
2107{
2108 sdev->request_queue = blk_mq_init_queue(&sdev->host->tag_set);
2109 if (IS_ERR(sdev->request_queue))
2110 return NULL;
2111
2112 sdev->request_queue->queuedata = sdev;
2113 __scsi_init_queue(sdev->host, sdev->request_queue);
2114 return sdev->request_queue;
2115}
2116
2117int scsi_mq_setup_tags(struct Scsi_Host *shost)
2118{
2119 unsigned int cmd_size, sgl_size, tbl_size;
2120
2121 tbl_size = shost->sg_tablesize;
2122 if (tbl_size > SG_CHUNK_SIZE)
2123 tbl_size = SG_CHUNK_SIZE;
2124 sgl_size = tbl_size * sizeof(struct scatterlist);
2125 cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size;
2126 if (scsi_host_get_prot(shost))
2127 cmd_size += sizeof(struct scsi_data_buffer) + sgl_size;
2128
2129 memset(&shost->tag_set, 0, sizeof(shost->tag_set));
2130 shost->tag_set.ops = &scsi_mq_ops;
2131 shost->tag_set.nr_hw_queues = shost->nr_hw_queues ? : 1;
2132 shost->tag_set.queue_depth = shost->can_queue;
2133 shost->tag_set.cmd_size = cmd_size;
2134 shost->tag_set.numa_node = NUMA_NO_NODE;
2135 shost->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
2136 shost->tag_set.flags |=
2137 BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
2138 shost->tag_set.driver_data = shost;
2139
2140 return blk_mq_alloc_tag_set(&shost->tag_set);
2141}
2142
2143void scsi_mq_destroy_tags(struct Scsi_Host *shost)
2144{
2145 blk_mq_free_tag_set(&shost->tag_set);
2146}
2147
2148/**
2149 * scsi_device_from_queue - return sdev associated with a request_queue
2150 * @q: The request queue to return the sdev from
2151 *
2152 * Return the sdev associated with a request queue or NULL if the
2153 * request_queue does not reference a SCSI device.
2154 */
2155struct scsi_device *scsi_device_from_queue(struct request_queue *q)
2156{
2157 struct scsi_device *sdev = NULL;
2158
2159 if (q->mq_ops) {
2160 if (q->mq_ops == &scsi_mq_ops)
2161 sdev = q->queuedata;
2162 } else if (q->request_fn == scsi_request_fn)
2163 sdev = q->queuedata;
2164 if (!sdev || !get_device(&sdev->sdev_gendev))
2165 sdev = NULL;
2166
2167 return sdev;
2168}
2169EXPORT_SYMBOL_GPL(scsi_device_from_queue);
2170
2171/*
2172 * Function: scsi_block_requests()
2173 *
2174 * Purpose: Utility function used by low-level drivers to prevent further
2175 * commands from being queued to the device.
2176 *
2177 * Arguments: shost - Host in question
2178 *
2179 * Returns: Nothing
2180 *
2181 * Lock status: No locks are assumed held.
2182 *
2183 * Notes: There is no timer nor any other means by which the requests
2184 * get unblocked other than the low-level driver calling
2185 * scsi_unblock_requests().
2186 */
2187void scsi_block_requests(struct Scsi_Host *shost)
2188{
2189 shost->host_self_blocked = 1;
2190}
2191EXPORT_SYMBOL(scsi_block_requests);
2192
2193/*
2194 * Function: scsi_unblock_requests()
2195 *
2196 * Purpose: Utility function used by low-level drivers to allow further
2197 * commands from being queued to the device.
2198 *
2199 * Arguments: shost - Host in question
2200 *
2201 * Returns: Nothing
2202 *
2203 * Lock status: No locks are assumed held.
2204 *
2205 * Notes: There is no timer nor any other means by which the requests
2206 * get unblocked other than the low-level driver calling
2207 * scsi_unblock_requests().
2208 *
2209 * This is done as an API function so that changes to the
2210 * internals of the scsi mid-layer won't require wholesale
2211 * changes to drivers that use this feature.
2212 */
2213void scsi_unblock_requests(struct Scsi_Host *shost)
2214{
2215 shost->host_self_blocked = 0;
2216 scsi_run_host_queues(shost);
2217}
2218EXPORT_SYMBOL(scsi_unblock_requests);
2219
2220int __init scsi_init_queue(void)
2221{
2222 scsi_sdb_cache = kmem_cache_create("scsi_data_buffer",
2223 sizeof(struct scsi_data_buffer),
2224 0, 0, NULL);
2225 if (!scsi_sdb_cache) {
2226 printk(KERN_ERR "SCSI: can't init scsi sdb cache\n");
2227 return -ENOMEM;
2228 }
2229
2230 return 0;
2231}
2232
2233void scsi_exit_queue(void)
2234{
2235 kmem_cache_destroy(scsi_sdb_cache);
2236}
2237
2238/**
2239 * scsi_mode_select - issue a mode select
2240 * @sdev: SCSI device to be queried
2241 * @pf: Page format bit (1 == standard, 0 == vendor specific)
2242 * @sp: Save page bit (0 == don't save, 1 == save)
2243 * @modepage: mode page being requested
2244 * @buffer: request buffer (may not be smaller than eight bytes)
2245 * @len: length of request buffer.
2246 * @timeout: command timeout
2247 * @retries: number of retries before failing
2248 * @data: returns a structure abstracting the mode header data
2249 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2250 * must be SCSI_SENSE_BUFFERSIZE big.
2251 *
2252 * Returns zero if successful; negative error number or scsi
2253 * status on error
2254 *
2255 */
2256int
2257scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
2258 unsigned char *buffer, int len, int timeout, int retries,
2259 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2260{
2261 unsigned char cmd[10];
2262 unsigned char *real_buffer;
2263 int ret;
2264
2265 memset(cmd, 0, sizeof(cmd));
2266 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
2267
2268 if (sdev->use_10_for_ms) {
2269 if (len > 65535)
2270 return -EINVAL;
2271 real_buffer = kmalloc(8 + len, GFP_KERNEL);
2272 if (!real_buffer)
2273 return -ENOMEM;
2274 memcpy(real_buffer + 8, buffer, len);
2275 len += 8;
2276 real_buffer[0] = 0;
2277 real_buffer[1] = 0;
2278 real_buffer[2] = data->medium_type;
2279 real_buffer[3] = data->device_specific;
2280 real_buffer[4] = data->longlba ? 0x01 : 0;
2281 real_buffer[5] = 0;
2282 real_buffer[6] = data->block_descriptor_length >> 8;
2283 real_buffer[7] = data->block_descriptor_length;
2284
2285 cmd[0] = MODE_SELECT_10;
2286 cmd[7] = len >> 8;
2287 cmd[8] = len;
2288 } else {
2289 if (len > 255 || data->block_descriptor_length > 255 ||
2290 data->longlba)
2291 return -EINVAL;
2292
2293 real_buffer = kmalloc(4 + len, GFP_KERNEL);
2294 if (!real_buffer)
2295 return -ENOMEM;
2296 memcpy(real_buffer + 4, buffer, len);
2297 len += 4;
2298 real_buffer[0] = 0;
2299 real_buffer[1] = data->medium_type;
2300 real_buffer[2] = data->device_specific;
2301 real_buffer[3] = data->block_descriptor_length;
2302
2303
2304 cmd[0] = MODE_SELECT;
2305 cmd[4] = len;
2306 }
2307
2308 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
2309 sshdr, timeout, retries, NULL);
2310 kfree(real_buffer);
2311 return ret;
2312}
2313EXPORT_SYMBOL_GPL(scsi_mode_select);
2314
2315/**
2316 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
2317 * @sdev: SCSI device to be queried
2318 * @dbd: set if mode sense will allow block descriptors to be returned
2319 * @modepage: mode page being requested
2320 * @buffer: request buffer (may not be smaller than eight bytes)
2321 * @len: length of request buffer.
2322 * @timeout: command timeout
2323 * @retries: number of retries before failing
2324 * @data: returns a structure abstracting the mode header data
2325 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2326 * must be SCSI_SENSE_BUFFERSIZE big.
2327 *
2328 * Returns zero if unsuccessful, or the header offset (either 4
2329 * or 8 depending on whether a six or ten byte command was
2330 * issued) if successful.
2331 */
2332int
2333scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
2334 unsigned char *buffer, int len, int timeout, int retries,
2335 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2336{
2337 unsigned char cmd[12];
2338 int use_10_for_ms;
2339 int header_length;
2340 int result, retry_count = retries;
2341 struct scsi_sense_hdr my_sshdr;
2342
2343 memset(data, 0, sizeof(*data));
2344 memset(&cmd[0], 0, 12);
2345 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
2346 cmd[2] = modepage;
2347
2348 /* caller might not be interested in sense, but we need it */
2349 if (!sshdr)
2350 sshdr = &my_sshdr;
2351
2352 retry:
2353 use_10_for_ms = sdev->use_10_for_ms;
2354
2355 if (use_10_for_ms) {
2356 if (len < 8)
2357 len = 8;
2358
2359 cmd[0] = MODE_SENSE_10;
2360 cmd[8] = len;
2361 header_length = 8;
2362 } else {
2363 if (len < 4)
2364 len = 4;
2365
2366 cmd[0] = MODE_SENSE;
2367 cmd[4] = len;
2368 header_length = 4;
2369 }
2370
2371 memset(buffer, 0, len);
2372
2373 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
2374 sshdr, timeout, retries, NULL);
2375
2376 /* This code looks awful: what it's doing is making sure an
2377 * ILLEGAL REQUEST sense return identifies the actual command
2378 * byte as the problem. MODE_SENSE commands can return
2379 * ILLEGAL REQUEST if the code page isn't supported */
2380
2381 if (use_10_for_ms && !scsi_status_is_good(result) &&
2382 (driver_byte(result) & DRIVER_SENSE)) {
2383 if (scsi_sense_valid(sshdr)) {
2384 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
2385 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
2386 /*
2387 * Invalid command operation code
2388 */
2389 sdev->use_10_for_ms = 0;
2390 goto retry;
2391 }
2392 }
2393 }
2394
2395 if(scsi_status_is_good(result)) {
2396 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
2397 (modepage == 6 || modepage == 8))) {
2398 /* Initio breakage? */
2399 header_length = 0;
2400 data->length = 13;
2401 data->medium_type = 0;
2402 data->device_specific = 0;
2403 data->longlba = 0;
2404 data->block_descriptor_length = 0;
2405 } else if(use_10_for_ms) {
2406 data->length = buffer[0]*256 + buffer[1] + 2;
2407 data->medium_type = buffer[2];
2408 data->device_specific = buffer[3];
2409 data->longlba = buffer[4] & 0x01;
2410 data->block_descriptor_length = buffer[6]*256
2411 + buffer[7];
2412 } else {
2413 data->length = buffer[0] + 1;
2414 data->medium_type = buffer[1];
2415 data->device_specific = buffer[2];
2416 data->block_descriptor_length = buffer[3];
2417 }
2418 data->header_length = header_length;
2419 } else if ((status_byte(result) == CHECK_CONDITION) &&
2420 scsi_sense_valid(sshdr) &&
2421 sshdr->sense_key == UNIT_ATTENTION && retry_count) {
2422 retry_count--;
2423 goto retry;
2424 }
2425
2426 return result;
2427}
2428EXPORT_SYMBOL(scsi_mode_sense);
2429
2430/**
2431 * scsi_test_unit_ready - test if unit is ready
2432 * @sdev: scsi device to change the state of.
2433 * @timeout: command timeout
2434 * @retries: number of retries before failing
2435 * @sshdr_external: Optional pointer to struct scsi_sense_hdr for
2436 * returning sense. Make sure that this is cleared before passing
2437 * in.
2438 *
2439 * Returns zero if unsuccessful or an error if TUR failed. For
2440 * removable media, UNIT_ATTENTION sets ->changed flag.
2441 **/
2442int
2443scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2444 struct scsi_sense_hdr *sshdr_external)
2445{
2446 char cmd[] = {
2447 TEST_UNIT_READY, 0, 0, 0, 0, 0,
2448 };
2449 struct scsi_sense_hdr *sshdr;
2450 int result;
2451
2452 if (!sshdr_external)
2453 sshdr = kzalloc(sizeof(*sshdr), GFP_KERNEL);
2454 else
2455 sshdr = sshdr_external;
2456
2457 /* try to eat the UNIT_ATTENTION if there are enough retries */
2458 do {
2459 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
2460 timeout, retries, NULL);
2461 if (sdev->removable && scsi_sense_valid(sshdr) &&
2462 sshdr->sense_key == UNIT_ATTENTION)
2463 sdev->changed = 1;
2464 } while (scsi_sense_valid(sshdr) &&
2465 sshdr->sense_key == UNIT_ATTENTION && --retries);
2466
2467 if (!sshdr_external)
2468 kfree(sshdr);
2469 return result;
2470}
2471EXPORT_SYMBOL(scsi_test_unit_ready);
2472
2473/**
2474 * scsi_device_set_state - Take the given device through the device state model.
2475 * @sdev: scsi device to change the state of.
2476 * @state: state to change to.
2477 *
2478 * Returns zero if unsuccessful or an error if the requested
2479 * transition is illegal.
2480 */
2481int
2482scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2483{
2484 enum scsi_device_state oldstate = sdev->sdev_state;
2485
2486 if (state == oldstate)
2487 return 0;
2488
2489 switch (state) {
2490 case SDEV_CREATED:
2491 switch (oldstate) {
2492 case SDEV_CREATED_BLOCK:
2493 break;
2494 default:
2495 goto illegal;
2496 }
2497 break;
2498
2499 case SDEV_RUNNING:
2500 switch (oldstate) {
2501 case SDEV_CREATED:
2502 case SDEV_OFFLINE:
2503 case SDEV_TRANSPORT_OFFLINE:
2504 case SDEV_QUIESCE:
2505 case SDEV_BLOCK:
2506 break;
2507 default:
2508 goto illegal;
2509 }
2510 break;
2511
2512 case SDEV_QUIESCE:
2513 switch (oldstate) {
2514 case SDEV_RUNNING:
2515 case SDEV_OFFLINE:
2516 case SDEV_TRANSPORT_OFFLINE:
2517 break;
2518 default:
2519 goto illegal;
2520 }
2521 break;
2522
2523 case SDEV_OFFLINE:
2524 case SDEV_TRANSPORT_OFFLINE:
2525 switch (oldstate) {
2526 case SDEV_CREATED:
2527 case SDEV_RUNNING:
2528 case SDEV_QUIESCE:
2529 case SDEV_BLOCK:
2530 break;
2531 default:
2532 goto illegal;
2533 }
2534 break;
2535
2536 case SDEV_BLOCK:
2537 switch (oldstate) {
2538 case SDEV_RUNNING:
2539 case SDEV_CREATED_BLOCK:
2540 break;
2541 default:
2542 goto illegal;
2543 }
2544 break;
2545
2546 case SDEV_CREATED_BLOCK:
2547 switch (oldstate) {
2548 case SDEV_CREATED:
2549 break;
2550 default:
2551 goto illegal;
2552 }
2553 break;
2554
2555 case SDEV_CANCEL:
2556 switch (oldstate) {
2557 case SDEV_CREATED:
2558 case SDEV_RUNNING:
2559 case SDEV_QUIESCE:
2560 case SDEV_OFFLINE:
2561 case SDEV_TRANSPORT_OFFLINE:
2562 case SDEV_BLOCK:
2563 break;
2564 default:
2565 goto illegal;
2566 }
2567 break;
2568
2569 case SDEV_DEL:
2570 switch (oldstate) {
2571 case SDEV_CREATED:
2572 case SDEV_RUNNING:
2573 case SDEV_OFFLINE:
2574 case SDEV_TRANSPORT_OFFLINE:
2575 case SDEV_CANCEL:
2576 case SDEV_CREATED_BLOCK:
2577 break;
2578 default:
2579 goto illegal;
2580 }
2581 break;
2582
2583 }
2584 sdev->sdev_state = state;
2585 return 0;
2586
2587 illegal:
2588 SCSI_LOG_ERROR_RECOVERY(1,
2589 sdev_printk(KERN_ERR, sdev,
2590 "Illegal state transition %s->%s",
2591 scsi_device_state_name(oldstate),
2592 scsi_device_state_name(state))
2593 );
2594 return -EINVAL;
2595}
2596EXPORT_SYMBOL(scsi_device_set_state);
2597
2598/**
2599 * sdev_evt_emit - emit a single SCSI device uevent
2600 * @sdev: associated SCSI device
2601 * @evt: event to emit
2602 *
2603 * Send a single uevent (scsi_event) to the associated scsi_device.
2604 */
2605static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2606{
2607 int idx = 0;
2608 char *envp[3];
2609
2610 switch (evt->evt_type) {
2611 case SDEV_EVT_MEDIA_CHANGE:
2612 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2613 break;
2614 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2615 scsi_rescan_device(&sdev->sdev_gendev);
2616 envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2617 break;
2618 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2619 envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2620 break;
2621 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2622 envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2623 break;
2624 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2625 envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2626 break;
2627 case SDEV_EVT_LUN_CHANGE_REPORTED:
2628 envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2629 break;
2630 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2631 envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
2632 break;
2633 default:
2634 /* do nothing */
2635 break;
2636 }
2637
2638 envp[idx++] = NULL;
2639
2640 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2641}
2642
2643/**
2644 * sdev_evt_thread - send a uevent for each scsi event
2645 * @work: work struct for scsi_device
2646 *
2647 * Dispatch queued events to their associated scsi_device kobjects
2648 * as uevents.
2649 */
2650void scsi_evt_thread(struct work_struct *work)
2651{
2652 struct scsi_device *sdev;
2653 enum scsi_device_event evt_type;
2654 LIST_HEAD(event_list);
2655
2656 sdev = container_of(work, struct scsi_device, event_work);
2657
2658 for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
2659 if (test_and_clear_bit(evt_type, sdev->pending_events))
2660 sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
2661
2662 while (1) {
2663 struct scsi_event *evt;
2664 struct list_head *this, *tmp;
2665 unsigned long flags;
2666
2667 spin_lock_irqsave(&sdev->list_lock, flags);
2668 list_splice_init(&sdev->event_list, &event_list);
2669 spin_unlock_irqrestore(&sdev->list_lock, flags);
2670
2671 if (list_empty(&event_list))
2672 break;
2673
2674 list_for_each_safe(this, tmp, &event_list) {
2675 evt = list_entry(this, struct scsi_event, node);
2676 list_del(&evt->node);
2677 scsi_evt_emit(sdev, evt);
2678 kfree(evt);
2679 }
2680 }
2681}
2682
2683/**
2684 * sdev_evt_send - send asserted event to uevent thread
2685 * @sdev: scsi_device event occurred on
2686 * @evt: event to send
2687 *
2688 * Assert scsi device event asynchronously.
2689 */
2690void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2691{
2692 unsigned long flags;
2693
2694#if 0
2695 /* FIXME: currently this check eliminates all media change events
2696 * for polled devices. Need to update to discriminate between AN
2697 * and polled events */
2698 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2699 kfree(evt);
2700 return;
2701 }
2702#endif
2703
2704 spin_lock_irqsave(&sdev->list_lock, flags);
2705 list_add_tail(&evt->node, &sdev->event_list);
2706 schedule_work(&sdev->event_work);
2707 spin_unlock_irqrestore(&sdev->list_lock, flags);
2708}
2709EXPORT_SYMBOL_GPL(sdev_evt_send);
2710
2711/**
2712 * sdev_evt_alloc - allocate a new scsi event
2713 * @evt_type: type of event to allocate
2714 * @gfpflags: GFP flags for allocation
2715 *
2716 * Allocates and returns a new scsi_event.
2717 */
2718struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2719 gfp_t gfpflags)
2720{
2721 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2722 if (!evt)
2723 return NULL;
2724
2725 evt->evt_type = evt_type;
2726 INIT_LIST_HEAD(&evt->node);
2727
2728 /* evt_type-specific initialization, if any */
2729 switch (evt_type) {
2730 case SDEV_EVT_MEDIA_CHANGE:
2731 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2732 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2733 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2734 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2735 case SDEV_EVT_LUN_CHANGE_REPORTED:
2736 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2737 default:
2738 /* do nothing */
2739 break;
2740 }
2741
2742 return evt;
2743}
2744EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2745
2746/**
2747 * sdev_evt_send_simple - send asserted event to uevent thread
2748 * @sdev: scsi_device event occurred on
2749 * @evt_type: type of event to send
2750 * @gfpflags: GFP flags for allocation
2751 *
2752 * Assert scsi device event asynchronously, given an event type.
2753 */
2754void sdev_evt_send_simple(struct scsi_device *sdev,
2755 enum scsi_device_event evt_type, gfp_t gfpflags)
2756{
2757 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2758 if (!evt) {
2759 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2760 evt_type);
2761 return;
2762 }
2763
2764 sdev_evt_send(sdev, evt);
2765}
2766EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2767
2768/**
2769 * scsi_request_fn_active() - number of kernel threads inside scsi_request_fn()
2770 * @sdev: SCSI device to count the number of scsi_request_fn() callers for.
2771 */
2772static int scsi_request_fn_active(struct scsi_device *sdev)
2773{
2774 struct request_queue *q = sdev->request_queue;
2775 int request_fn_active;
2776
2777 WARN_ON_ONCE(sdev->host->use_blk_mq);
2778
2779 spin_lock_irq(q->queue_lock);
2780 request_fn_active = q->request_fn_active;
2781 spin_unlock_irq(q->queue_lock);
2782
2783 return request_fn_active;
2784}
2785
2786/**
2787 * scsi_wait_for_queuecommand() - wait for ongoing queuecommand() calls
2788 * @sdev: SCSI device pointer.
2789 *
2790 * Wait until the ongoing shost->hostt->queuecommand() calls that are
2791 * invoked from scsi_request_fn() have finished.
2792 */
2793static void scsi_wait_for_queuecommand(struct scsi_device *sdev)
2794{
2795 WARN_ON_ONCE(sdev->host->use_blk_mq);
2796
2797 while (scsi_request_fn_active(sdev))
2798 msleep(20);
2799}
2800
2801/**
2802 * scsi_device_quiesce - Block user issued commands.
2803 * @sdev: scsi device to quiesce.
2804 *
2805 * This works by trying to transition to the SDEV_QUIESCE state
2806 * (which must be a legal transition). When the device is in this
2807 * state, only special requests will be accepted, all others will
2808 * be deferred. Since special requests may also be requeued requests,
2809 * a successful return doesn't guarantee the device will be
2810 * totally quiescent.
2811 *
2812 * Must be called with user context, may sleep.
2813 *
2814 * Returns zero if unsuccessful or an error if not.
2815 */
2816int
2817scsi_device_quiesce(struct scsi_device *sdev)
2818{
2819 int err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2820 if (err)
2821 return err;
2822
2823 scsi_run_queue(sdev->request_queue);
2824 while (atomic_read(&sdev->device_busy)) {
2825 msleep_interruptible(200);
2826 scsi_run_queue(sdev->request_queue);
2827 }
2828 return 0;
2829}
2830EXPORT_SYMBOL(scsi_device_quiesce);
2831
2832/**
2833 * scsi_device_resume - Restart user issued commands to a quiesced device.
2834 * @sdev: scsi device to resume.
2835 *
2836 * Moves the device from quiesced back to running and restarts the
2837 * queues.
2838 *
2839 * Must be called with user context, may sleep.
2840 */
2841void scsi_device_resume(struct scsi_device *sdev)
2842{
2843 /* check if the device state was mutated prior to resume, and if
2844 * so assume the state is being managed elsewhere (for example
2845 * device deleted during suspend)
2846 */
2847 if (sdev->sdev_state != SDEV_QUIESCE ||
2848 scsi_device_set_state(sdev, SDEV_RUNNING))
2849 return;
2850 scsi_run_queue(sdev->request_queue);
2851}
2852EXPORT_SYMBOL(scsi_device_resume);
2853
2854static void
2855device_quiesce_fn(struct scsi_device *sdev, void *data)
2856{
2857 scsi_device_quiesce(sdev);
2858}
2859
2860void
2861scsi_target_quiesce(struct scsi_target *starget)
2862{
2863 starget_for_each_device(starget, NULL, device_quiesce_fn);
2864}
2865EXPORT_SYMBOL(scsi_target_quiesce);
2866
2867static void
2868device_resume_fn(struct scsi_device *sdev, void *data)
2869{
2870 scsi_device_resume(sdev);
2871}
2872
2873void
2874scsi_target_resume(struct scsi_target *starget)
2875{
2876 starget_for_each_device(starget, NULL, device_resume_fn);
2877}
2878EXPORT_SYMBOL(scsi_target_resume);
2879
2880/**
2881 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state
2882 * @sdev: device to block
2883 * @wait: Whether or not to wait until ongoing .queuecommand() /
2884 * .queue_rq() calls have finished.
2885 *
2886 * Block request made by scsi lld's to temporarily stop all
2887 * scsi commands on the specified device. May sleep.
2888 *
2889 * Returns zero if successful or error if not
2890 *
2891 * Notes:
2892 * This routine transitions the device to the SDEV_BLOCK state
2893 * (which must be a legal transition). When the device is in this
2894 * state, all commands are deferred until the scsi lld reenables
2895 * the device with scsi_device_unblock or device_block_tmo fires.
2896 *
2897 * To do: avoid that scsi_send_eh_cmnd() calls queuecommand() after
2898 * scsi_internal_device_block() has blocked a SCSI device and also
2899 * remove the rport mutex lock and unlock calls from srp_queuecommand().
2900 */
2901int
2902scsi_internal_device_block(struct scsi_device *sdev, bool wait)
2903{
2904 struct request_queue *q = sdev->request_queue;
2905 unsigned long flags;
2906 int err = 0;
2907
2908 err = scsi_device_set_state(sdev, SDEV_BLOCK);
2909 if (err) {
2910 err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2911
2912 if (err)
2913 return err;
2914 }
2915
2916 /*
2917 * The device has transitioned to SDEV_BLOCK. Stop the
2918 * block layer from calling the midlayer with this device's
2919 * request queue.
2920 */
2921 if (q->mq_ops) {
2922 if (wait)
2923 blk_mq_quiesce_queue(q);
2924 else
2925 blk_mq_stop_hw_queues(q);
2926 } else {
2927 spin_lock_irqsave(q->queue_lock, flags);
2928 blk_stop_queue(q);
2929 spin_unlock_irqrestore(q->queue_lock, flags);
2930 if (wait)
2931 scsi_wait_for_queuecommand(sdev);
2932 }
2933
2934 return 0;
2935}
2936EXPORT_SYMBOL_GPL(scsi_internal_device_block);
2937
2938/**
2939 * scsi_internal_device_unblock - resume a device after a block request
2940 * @sdev: device to resume
2941 * @new_state: state to set devices to after unblocking
2942 *
2943 * Called by scsi lld's or the midlayer to restart the device queue
2944 * for the previously suspended scsi device. Called from interrupt or
2945 * normal process context.
2946 *
2947 * Returns zero if successful or error if not.
2948 *
2949 * Notes:
2950 * This routine transitions the device to the SDEV_RUNNING state
2951 * or to one of the offline states (which must be a legal transition)
2952 * allowing the midlayer to goose the queue for this device.
2953 */
2954int
2955scsi_internal_device_unblock(struct scsi_device *sdev,
2956 enum scsi_device_state new_state)
2957{
2958 struct request_queue *q = sdev->request_queue;
2959 unsigned long flags;
2960
2961 /*
2962 * Try to transition the scsi device to SDEV_RUNNING or one of the
2963 * offlined states and goose the device queue if successful.
2964 */
2965 if ((sdev->sdev_state == SDEV_BLOCK) ||
2966 (sdev->sdev_state == SDEV_TRANSPORT_OFFLINE))
2967 sdev->sdev_state = new_state;
2968 else if (sdev->sdev_state == SDEV_CREATED_BLOCK) {
2969 if (new_state == SDEV_TRANSPORT_OFFLINE ||
2970 new_state == SDEV_OFFLINE)
2971 sdev->sdev_state = new_state;
2972 else
2973 sdev->sdev_state = SDEV_CREATED;
2974 } else if (sdev->sdev_state != SDEV_CANCEL &&
2975 sdev->sdev_state != SDEV_OFFLINE)
2976 return -EINVAL;
2977
2978 if (q->mq_ops) {
2979 blk_mq_start_stopped_hw_queues(q, false);
2980 } else {
2981 spin_lock_irqsave(q->queue_lock, flags);
2982 blk_start_queue(q);
2983 spin_unlock_irqrestore(q->queue_lock, flags);
2984 }
2985
2986 return 0;
2987}
2988EXPORT_SYMBOL_GPL(scsi_internal_device_unblock);
2989
2990static void
2991device_block(struct scsi_device *sdev, void *data)
2992{
2993 scsi_internal_device_block(sdev, true);
2994}
2995
2996static int
2997target_block(struct device *dev, void *data)
2998{
2999 if (scsi_is_target_device(dev))
3000 starget_for_each_device(to_scsi_target(dev), NULL,
3001 device_block);
3002 return 0;
3003}
3004
3005void
3006scsi_target_block(struct device *dev)
3007{
3008 if (scsi_is_target_device(dev))
3009 starget_for_each_device(to_scsi_target(dev), NULL,
3010 device_block);
3011 else
3012 device_for_each_child(dev, NULL, target_block);
3013}
3014EXPORT_SYMBOL_GPL(scsi_target_block);
3015
3016static void
3017device_unblock(struct scsi_device *sdev, void *data)
3018{
3019 scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
3020}
3021
3022static int
3023target_unblock(struct device *dev, void *data)
3024{
3025 if (scsi_is_target_device(dev))
3026 starget_for_each_device(to_scsi_target(dev), data,
3027 device_unblock);
3028 return 0;
3029}
3030
3031void
3032scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
3033{
3034 if (scsi_is_target_device(dev))
3035 starget_for_each_device(to_scsi_target(dev), &new_state,
3036 device_unblock);
3037 else
3038 device_for_each_child(dev, &new_state, target_unblock);
3039}
3040EXPORT_SYMBOL_GPL(scsi_target_unblock);
3041
3042/**
3043 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
3044 * @sgl: scatter-gather list
3045 * @sg_count: number of segments in sg
3046 * @offset: offset in bytes into sg, on return offset into the mapped area
3047 * @len: bytes to map, on return number of bytes mapped
3048 *
3049 * Returns virtual address of the start of the mapped page
3050 */
3051void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
3052 size_t *offset, size_t *len)
3053{
3054 int i;
3055 size_t sg_len = 0, len_complete = 0;
3056 struct scatterlist *sg;
3057 struct page *page;
3058
3059 WARN_ON(!irqs_disabled());
3060
3061 for_each_sg(sgl, sg, sg_count, i) {
3062 len_complete = sg_len; /* Complete sg-entries */
3063 sg_len += sg->length;
3064 if (sg_len > *offset)
3065 break;
3066 }
3067
3068 if (unlikely(i == sg_count)) {
3069 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
3070 "elements %d\n",
3071 __func__, sg_len, *offset, sg_count);
3072 WARN_ON(1);
3073 return NULL;
3074 }
3075
3076 /* Offset starting from the beginning of first page in this sg-entry */
3077 *offset = *offset - len_complete + sg->offset;
3078
3079 /* Assumption: contiguous pages can be accessed as "page + i" */
3080 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
3081 *offset &= ~PAGE_MASK;
3082
3083 /* Bytes in this sg-entry from *offset to the end of the page */
3084 sg_len = PAGE_SIZE - *offset;
3085 if (*len > sg_len)
3086 *len = sg_len;
3087
3088 return kmap_atomic(page);
3089}
3090EXPORT_SYMBOL(scsi_kmap_atomic_sg);
3091
3092/**
3093 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
3094 * @virt: virtual address to be unmapped
3095 */
3096void scsi_kunmap_atomic_sg(void *virt)
3097{
3098 kunmap_atomic(virt);
3099}
3100EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
3101
3102void sdev_disable_disk_events(struct scsi_device *sdev)
3103{
3104 atomic_inc(&sdev->disk_events_disable_depth);
3105}
3106EXPORT_SYMBOL(sdev_disable_disk_events);
3107
3108void sdev_enable_disk_events(struct scsi_device *sdev)
3109{
3110 if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0))
3111 return;
3112 atomic_dec(&sdev->disk_events_disable_depth);
3113}
3114EXPORT_SYMBOL(sdev_enable_disk_events);
3115
3116/**
3117 * scsi_vpd_lun_id - return a unique device identification
3118 * @sdev: SCSI device
3119 * @id: buffer for the identification
3120 * @id_len: length of the buffer
3121 *
3122 * Copies a unique device identification into @id based
3123 * on the information in the VPD page 0x83 of the device.
3124 * The string will be formatted as a SCSI name string.
3125 *
3126 * Returns the length of the identification or error on failure.
3127 * If the identifier is longer than the supplied buffer the actual
3128 * identifier length is returned and the buffer is not zero-padded.
3129 */
3130int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len)
3131{
3132 u8 cur_id_type = 0xff;
3133 u8 cur_id_size = 0;
3134 unsigned char *d, *cur_id_str;
3135 unsigned char __rcu *vpd_pg83;
3136 int id_size = -EINVAL;
3137
3138 rcu_read_lock();
3139 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3140 if (!vpd_pg83) {
3141 rcu_read_unlock();
3142 return -ENXIO;
3143 }
3144
3145 /*
3146 * Look for the correct descriptor.
3147 * Order of preference for lun descriptor:
3148 * - SCSI name string
3149 * - NAA IEEE Registered Extended
3150 * - EUI-64 based 16-byte
3151 * - EUI-64 based 12-byte
3152 * - NAA IEEE Registered
3153 * - NAA IEEE Extended
3154 * - T10 Vendor ID
3155 * as longer descriptors reduce the likelyhood
3156 * of identification clashes.
3157 */
3158
3159 /* The id string must be at least 20 bytes + terminating NULL byte */
3160 if (id_len < 21) {
3161 rcu_read_unlock();
3162 return -EINVAL;
3163 }
3164
3165 memset(id, 0, id_len);
3166 d = vpd_pg83 + 4;
3167 while (d < vpd_pg83 + sdev->vpd_pg83_len) {
3168 /* Skip designators not referring to the LUN */
3169 if ((d[1] & 0x30) != 0x00)
3170 goto next_desig;
3171
3172 switch (d[1] & 0xf) {
3173 case 0x1:
3174 /* T10 Vendor ID */
3175 if (cur_id_size > d[3])
3176 break;
3177 /* Prefer anything */
3178 if (cur_id_type > 0x01 && cur_id_type != 0xff)
3179 break;
3180 cur_id_size = d[3];
3181 if (cur_id_size + 4 > id_len)
3182 cur_id_size = id_len - 4;
3183 cur_id_str = d + 4;
3184 cur_id_type = d[1] & 0xf;
3185 id_size = snprintf(id, id_len, "t10.%*pE",
3186 cur_id_size, cur_id_str);
3187 break;
3188 case 0x2:
3189 /* EUI-64 */
3190 if (cur_id_size > d[3])
3191 break;
3192 /* Prefer NAA IEEE Registered Extended */
3193 if (cur_id_type == 0x3 &&
3194 cur_id_size == d[3])
3195 break;
3196 cur_id_size = d[3];
3197 cur_id_str = d + 4;
3198 cur_id_type = d[1] & 0xf;
3199 switch (cur_id_size) {
3200 case 8:
3201 id_size = snprintf(id, id_len,
3202 "eui.%8phN",
3203 cur_id_str);
3204 break;
3205 case 12:
3206 id_size = snprintf(id, id_len,
3207 "eui.%12phN",
3208 cur_id_str);
3209 break;
3210 case 16:
3211 id_size = snprintf(id, id_len,
3212 "eui.%16phN",
3213 cur_id_str);
3214 break;
3215 default:
3216 cur_id_size = 0;
3217 break;
3218 }
3219 break;
3220 case 0x3:
3221 /* NAA */
3222 if (cur_id_size > d[3])
3223 break;
3224 cur_id_size = d[3];
3225 cur_id_str = d + 4;
3226 cur_id_type = d[1] & 0xf;
3227 switch (cur_id_size) {
3228 case 8:
3229 id_size = snprintf(id, id_len,
3230 "naa.%8phN",
3231 cur_id_str);
3232 break;
3233 case 16:
3234 id_size = snprintf(id, id_len,
3235 "naa.%16phN",
3236 cur_id_str);
3237 break;
3238 default:
3239 cur_id_size = 0;
3240 break;
3241 }
3242 break;
3243 case 0x8:
3244 /* SCSI name string */
3245 if (cur_id_size + 4 > d[3])
3246 break;
3247 /* Prefer others for truncated descriptor */
3248 if (cur_id_size && d[3] > id_len)
3249 break;
3250 cur_id_size = id_size = d[3];
3251 cur_id_str = d + 4;
3252 cur_id_type = d[1] & 0xf;
3253 if (cur_id_size >= id_len)
3254 cur_id_size = id_len - 1;
3255 memcpy(id, cur_id_str, cur_id_size);
3256 /* Decrease priority for truncated descriptor */
3257 if (cur_id_size != id_size)
3258 cur_id_size = 6;
3259 break;
3260 default:
3261 break;
3262 }
3263next_desig:
3264 d += d[3] + 4;
3265 }
3266 rcu_read_unlock();
3267
3268 return id_size;
3269}
3270EXPORT_SYMBOL(scsi_vpd_lun_id);
3271
3272/*
3273 * scsi_vpd_tpg_id - return a target port group identifier
3274 * @sdev: SCSI device
3275 *
3276 * Returns the Target Port Group identifier from the information
3277 * froom VPD page 0x83 of the device.
3278 *
3279 * Returns the identifier or error on failure.
3280 */
3281int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id)
3282{
3283 unsigned char *d;
3284 unsigned char __rcu *vpd_pg83;
3285 int group_id = -EAGAIN, rel_port = -1;
3286
3287 rcu_read_lock();
3288 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3289 if (!vpd_pg83) {
3290 rcu_read_unlock();
3291 return -ENXIO;
3292 }
3293
3294 d = sdev->vpd_pg83 + 4;
3295 while (d < sdev->vpd_pg83 + sdev->vpd_pg83_len) {
3296 switch (d[1] & 0xf) {
3297 case 0x4:
3298 /* Relative target port */
3299 rel_port = get_unaligned_be16(&d[6]);
3300 break;
3301 case 0x5:
3302 /* Target port group */
3303 group_id = get_unaligned_be16(&d[6]);
3304 break;
3305 default:
3306 break;
3307 }
3308 d += d[3] + 4;
3309 }
3310 rcu_read_unlock();
3311
3312 if (group_id >= 0 && rel_id && rel_port != -1)
3313 *rel_id = rel_port;
3314
3315 return group_id;
3316}
3317EXPORT_SYMBOL(scsi_vpd_tpg_id);