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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 if (msecs) {
126 blk_mq_requeue_request(rq, false);
127 blk_mq_delay_kick_requeue_list(rq->q, msecs);
128 } else
129 blk_mq_requeue_request(rq, true);
130}
131
132/**
133 * __scsi_queue_insert - private queue insertion
134 * @cmd: The SCSI command being requeued
135 * @reason: The reason for the requeue
136 * @unbusy: Whether the queue should be unbusied
137 *
138 * This is a private queue insertion. The public interface
139 * scsi_queue_insert() always assumes the queue should be unbusied
140 * because it's always called before the completion. This function is
141 * for a requeue after completion, which should only occur in this
142 * file.
143 */
144static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy)
145{
146 struct scsi_device *device = cmd->device;
147
148 SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd,
149 "Inserting command %p into mlqueue\n", cmd));
150
151 scsi_set_blocked(cmd, reason);
152
153 /*
154 * Decrement the counters, since these commands are no longer
155 * active on the host/device.
156 */
157 if (unbusy)
158 scsi_device_unbusy(device, cmd);
159
160 /*
161 * Requeue this command. It will go before all other commands
162 * that are already in the queue. Schedule requeue work under
163 * lock such that the kblockd_schedule_work() call happens
164 * before blk_mq_destroy_queue() finishes.
165 */
166 cmd->result = 0;
167
168 blk_mq_requeue_request(scsi_cmd_to_rq(cmd), true);
169}
170
171/**
172 * scsi_queue_insert - Reinsert a command in the queue.
173 * @cmd: command that we are adding to queue.
174 * @reason: why we are inserting command to queue.
175 *
176 * We do this for one of two cases. Either the host is busy and it cannot accept
177 * any more commands for the time being, or the device returned QUEUE_FULL and
178 * can accept no more commands.
179 *
180 * Context: This could be called either from an interrupt context or a normal
181 * process context.
182 */
183void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
184{
185 __scsi_queue_insert(cmd, reason, true);
186}
187
188
189/**
190 * __scsi_execute - insert request and wait for the result
191 * @sdev: scsi device
192 * @cmd: scsi command
193 * @data_direction: data direction
194 * @buffer: data buffer
195 * @bufflen: len of buffer
196 * @sense: optional sense buffer
197 * @sshdr: optional decoded sense header
198 * @timeout: request timeout in HZ
199 * @retries: number of times to retry request
200 * @flags: flags for ->cmd_flags
201 * @rq_flags: flags for ->rq_flags
202 * @resid: optional residual length
203 *
204 * Returns the scsi_cmnd result field if a command was executed, or a negative
205 * Linux error code if we didn't get that far.
206 */
207int __scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
208 int data_direction, void *buffer, unsigned bufflen,
209 unsigned char *sense, struct scsi_sense_hdr *sshdr,
210 int timeout, int retries, blk_opf_t flags,
211 req_flags_t rq_flags, int *resid)
212{
213 struct request *req;
214 struct scsi_cmnd *scmd;
215 int ret;
216
217 req = scsi_alloc_request(sdev->request_queue,
218 data_direction == DMA_TO_DEVICE ?
219 REQ_OP_DRV_OUT : REQ_OP_DRV_IN,
220 rq_flags & RQF_PM ? BLK_MQ_REQ_PM : 0);
221 if (IS_ERR(req))
222 return PTR_ERR(req);
223
224 if (bufflen) {
225 ret = blk_rq_map_kern(sdev->request_queue, req,
226 buffer, bufflen, GFP_NOIO);
227 if (ret)
228 goto out;
229 }
230 scmd = blk_mq_rq_to_pdu(req);
231 scmd->cmd_len = COMMAND_SIZE(cmd[0]);
232 memcpy(scmd->cmnd, cmd, scmd->cmd_len);
233 scmd->allowed = retries;
234 req->timeout = timeout;
235 req->cmd_flags |= flags;
236 req->rq_flags |= rq_flags | RQF_QUIET;
237
238 /*
239 * head injection *required* here otherwise quiesce won't work
240 */
241 blk_execute_rq(req, true);
242
243 /*
244 * Some devices (USB mass-storage in particular) may transfer
245 * garbage data together with a residue indicating that the data
246 * is invalid. Prevent the garbage from being misinterpreted
247 * and prevent security leaks by zeroing out the excess data.
248 */
249 if (unlikely(scmd->resid_len > 0 && scmd->resid_len <= bufflen))
250 memset(buffer + bufflen - scmd->resid_len, 0, scmd->resid_len);
251
252 if (resid)
253 *resid = scmd->resid_len;
254 if (sense && scmd->sense_len)
255 memcpy(sense, scmd->sense_buffer, SCSI_SENSE_BUFFERSIZE);
256 if (sshdr)
257 scsi_normalize_sense(scmd->sense_buffer, scmd->sense_len,
258 sshdr);
259 ret = scmd->result;
260 out:
261 blk_mq_free_request(req);
262
263 return ret;
264}
265EXPORT_SYMBOL(__scsi_execute);
266
267/*
268 * Wake up the error handler if necessary. Avoid as follows that the error
269 * handler is not woken up if host in-flight requests number ==
270 * shost->host_failed: use call_rcu() in scsi_eh_scmd_add() in combination
271 * with an RCU read lock in this function to ensure that this function in
272 * its entirety either finishes before scsi_eh_scmd_add() increases the
273 * host_failed counter or that it notices the shost state change made by
274 * scsi_eh_scmd_add().
275 */
276static void scsi_dec_host_busy(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
277{
278 unsigned long flags;
279
280 rcu_read_lock();
281 __clear_bit(SCMD_STATE_INFLIGHT, &cmd->state);
282 if (unlikely(scsi_host_in_recovery(shost))) {
283 spin_lock_irqsave(shost->host_lock, flags);
284 if (shost->host_failed || shost->host_eh_scheduled)
285 scsi_eh_wakeup(shost);
286 spin_unlock_irqrestore(shost->host_lock, flags);
287 }
288 rcu_read_unlock();
289}
290
291void scsi_device_unbusy(struct scsi_device *sdev, struct scsi_cmnd *cmd)
292{
293 struct Scsi_Host *shost = sdev->host;
294 struct scsi_target *starget = scsi_target(sdev);
295
296 scsi_dec_host_busy(shost, cmd);
297
298 if (starget->can_queue > 0)
299 atomic_dec(&starget->target_busy);
300
301 sbitmap_put(&sdev->budget_map, cmd->budget_token);
302 cmd->budget_token = -1;
303}
304
305static void scsi_kick_queue(struct request_queue *q)
306{
307 blk_mq_run_hw_queues(q, false);
308}
309
310/*
311 * Kick the queue of SCSI device @sdev if @sdev != current_sdev. Called with
312 * interrupts disabled.
313 */
314static void scsi_kick_sdev_queue(struct scsi_device *sdev, void *data)
315{
316 struct scsi_device *current_sdev = data;
317
318 if (sdev != current_sdev)
319 blk_mq_run_hw_queues(sdev->request_queue, true);
320}
321
322/*
323 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
324 * and call blk_run_queue for all the scsi_devices on the target -
325 * including current_sdev first.
326 *
327 * Called with *no* scsi locks held.
328 */
329static void scsi_single_lun_run(struct scsi_device *current_sdev)
330{
331 struct Scsi_Host *shost = current_sdev->host;
332 struct scsi_target *starget = scsi_target(current_sdev);
333 unsigned long flags;
334
335 spin_lock_irqsave(shost->host_lock, flags);
336 starget->starget_sdev_user = NULL;
337 spin_unlock_irqrestore(shost->host_lock, flags);
338
339 /*
340 * Call blk_run_queue for all LUNs on the target, starting with
341 * current_sdev. We race with others (to set starget_sdev_user),
342 * but in most cases, we will be first. Ideally, each LU on the
343 * target would get some limited time or requests on the target.
344 */
345 scsi_kick_queue(current_sdev->request_queue);
346
347 spin_lock_irqsave(shost->host_lock, flags);
348 if (!starget->starget_sdev_user)
349 __starget_for_each_device(starget, current_sdev,
350 scsi_kick_sdev_queue);
351 spin_unlock_irqrestore(shost->host_lock, flags);
352}
353
354static inline bool scsi_device_is_busy(struct scsi_device *sdev)
355{
356 if (scsi_device_busy(sdev) >= sdev->queue_depth)
357 return true;
358 if (atomic_read(&sdev->device_blocked) > 0)
359 return true;
360 return false;
361}
362
363static inline bool scsi_target_is_busy(struct scsi_target *starget)
364{
365 if (starget->can_queue > 0) {
366 if (atomic_read(&starget->target_busy) >= starget->can_queue)
367 return true;
368 if (atomic_read(&starget->target_blocked) > 0)
369 return true;
370 }
371 return false;
372}
373
374static inline bool scsi_host_is_busy(struct Scsi_Host *shost)
375{
376 if (atomic_read(&shost->host_blocked) > 0)
377 return true;
378 if (shost->host_self_blocked)
379 return true;
380 return false;
381}
382
383static void scsi_starved_list_run(struct Scsi_Host *shost)
384{
385 LIST_HEAD(starved_list);
386 struct scsi_device *sdev;
387 unsigned long flags;
388
389 spin_lock_irqsave(shost->host_lock, flags);
390 list_splice_init(&shost->starved_list, &starved_list);
391
392 while (!list_empty(&starved_list)) {
393 struct request_queue *slq;
394
395 /*
396 * As long as shost is accepting commands and we have
397 * starved queues, call blk_run_queue. scsi_request_fn
398 * drops the queue_lock and can add us back to the
399 * starved_list.
400 *
401 * host_lock protects the starved_list and starved_entry.
402 * scsi_request_fn must get the host_lock before checking
403 * or modifying starved_list or starved_entry.
404 */
405 if (scsi_host_is_busy(shost))
406 break;
407
408 sdev = list_entry(starved_list.next,
409 struct scsi_device, starved_entry);
410 list_del_init(&sdev->starved_entry);
411 if (scsi_target_is_busy(scsi_target(sdev))) {
412 list_move_tail(&sdev->starved_entry,
413 &shost->starved_list);
414 continue;
415 }
416
417 /*
418 * Once we drop the host lock, a racing scsi_remove_device()
419 * call may remove the sdev from the starved list and destroy
420 * it and the queue. Mitigate by taking a reference to the
421 * queue and never touching the sdev again after we drop the
422 * host lock. Note: if __scsi_remove_device() invokes
423 * blk_mq_destroy_queue() before the queue is run from this
424 * function then blk_run_queue() will return immediately since
425 * blk_mq_destroy_queue() marks the queue with QUEUE_FLAG_DYING.
426 */
427 slq = sdev->request_queue;
428 if (!blk_get_queue(slq))
429 continue;
430 spin_unlock_irqrestore(shost->host_lock, flags);
431
432 scsi_kick_queue(slq);
433 blk_put_queue(slq);
434
435 spin_lock_irqsave(shost->host_lock, flags);
436 }
437 /* put any unprocessed entries back */
438 list_splice(&starved_list, &shost->starved_list);
439 spin_unlock_irqrestore(shost->host_lock, flags);
440}
441
442/**
443 * scsi_run_queue - Select a proper request queue to serve next.
444 * @q: last request's queue
445 *
446 * The previous command was completely finished, start a new one if possible.
447 */
448static void scsi_run_queue(struct request_queue *q)
449{
450 struct scsi_device *sdev = q->queuedata;
451
452 if (scsi_target(sdev)->single_lun)
453 scsi_single_lun_run(sdev);
454 if (!list_empty(&sdev->host->starved_list))
455 scsi_starved_list_run(sdev->host);
456
457 blk_mq_run_hw_queues(q, false);
458}
459
460void scsi_requeue_run_queue(struct work_struct *work)
461{
462 struct scsi_device *sdev;
463 struct request_queue *q;
464
465 sdev = container_of(work, struct scsi_device, requeue_work);
466 q = sdev->request_queue;
467 scsi_run_queue(q);
468}
469
470void scsi_run_host_queues(struct Scsi_Host *shost)
471{
472 struct scsi_device *sdev;
473
474 shost_for_each_device(sdev, shost)
475 scsi_run_queue(sdev->request_queue);
476}
477
478static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
479{
480 if (!blk_rq_is_passthrough(scsi_cmd_to_rq(cmd))) {
481 struct scsi_driver *drv = scsi_cmd_to_driver(cmd);
482
483 if (drv->uninit_command)
484 drv->uninit_command(cmd);
485 }
486}
487
488void scsi_free_sgtables(struct scsi_cmnd *cmd)
489{
490 if (cmd->sdb.table.nents)
491 sg_free_table_chained(&cmd->sdb.table,
492 SCSI_INLINE_SG_CNT);
493 if (scsi_prot_sg_count(cmd))
494 sg_free_table_chained(&cmd->prot_sdb->table,
495 SCSI_INLINE_PROT_SG_CNT);
496}
497EXPORT_SYMBOL_GPL(scsi_free_sgtables);
498
499static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
500{
501 scsi_free_sgtables(cmd);
502 scsi_uninit_cmd(cmd);
503}
504
505static void scsi_run_queue_async(struct scsi_device *sdev)
506{
507 if (scsi_target(sdev)->single_lun ||
508 !list_empty(&sdev->host->starved_list)) {
509 kblockd_schedule_work(&sdev->requeue_work);
510 } else {
511 /*
512 * smp_mb() present in sbitmap_queue_clear() or implied in
513 * .end_io is for ordering writing .device_busy in
514 * scsi_device_unbusy() and reading sdev->restarts.
515 */
516 int old = atomic_read(&sdev->restarts);
517
518 /*
519 * ->restarts has to be kept as non-zero if new budget
520 * contention occurs.
521 *
522 * No need to run queue when either another re-run
523 * queue wins in updating ->restarts or a new budget
524 * contention occurs.
525 */
526 if (old && atomic_cmpxchg(&sdev->restarts, old, 0) == old)
527 blk_mq_run_hw_queues(sdev->request_queue, true);
528 }
529}
530
531/* Returns false when no more bytes to process, true if there are more */
532static bool scsi_end_request(struct request *req, blk_status_t error,
533 unsigned int bytes)
534{
535 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
536 struct scsi_device *sdev = cmd->device;
537 struct request_queue *q = sdev->request_queue;
538
539 if (blk_update_request(req, error, bytes))
540 return true;
541
542 // XXX:
543 if (blk_queue_add_random(q))
544 add_disk_randomness(req->q->disk);
545
546 if (!blk_rq_is_passthrough(req)) {
547 WARN_ON_ONCE(!(cmd->flags & SCMD_INITIALIZED));
548 cmd->flags &= ~SCMD_INITIALIZED;
549 }
550
551 /*
552 * Calling rcu_barrier() is not necessary here because the
553 * SCSI error handler guarantees that the function called by
554 * call_rcu() has been called before scsi_end_request() is
555 * called.
556 */
557 destroy_rcu_head(&cmd->rcu);
558
559 /*
560 * In the MQ case the command gets freed by __blk_mq_end_request,
561 * so we have to do all cleanup that depends on it earlier.
562 *
563 * We also can't kick the queues from irq context, so we
564 * will have to defer it to a workqueue.
565 */
566 scsi_mq_uninit_cmd(cmd);
567
568 /*
569 * queue is still alive, so grab the ref for preventing it
570 * from being cleaned up during running queue.
571 */
572 percpu_ref_get(&q->q_usage_counter);
573
574 __blk_mq_end_request(req, error);
575
576 scsi_run_queue_async(sdev);
577
578 percpu_ref_put(&q->q_usage_counter);
579 return false;
580}
581
582static inline u8 get_scsi_ml_byte(int result)
583{
584 return (result >> 8) & 0xff;
585}
586
587/**
588 * scsi_result_to_blk_status - translate a SCSI result code into blk_status_t
589 * @result: scsi error code
590 *
591 * Translate a SCSI result code into a blk_status_t value.
592 */
593static blk_status_t scsi_result_to_blk_status(int result)
594{
595 /*
596 * Check the scsi-ml byte first in case we converted a host or status
597 * byte.
598 */
599 switch (get_scsi_ml_byte(result)) {
600 case SCSIML_STAT_OK:
601 break;
602 case SCSIML_STAT_RESV_CONFLICT:
603 return BLK_STS_NEXUS;
604 case SCSIML_STAT_NOSPC:
605 return BLK_STS_NOSPC;
606 case SCSIML_STAT_MED_ERROR:
607 return BLK_STS_MEDIUM;
608 case SCSIML_STAT_TGT_FAILURE:
609 return BLK_STS_TARGET;
610 }
611
612 switch (host_byte(result)) {
613 case DID_OK:
614 if (scsi_status_is_good(result))
615 return BLK_STS_OK;
616 return BLK_STS_IOERR;
617 case DID_TRANSPORT_FAILFAST:
618 case DID_TRANSPORT_MARGINAL:
619 return BLK_STS_TRANSPORT;
620 default:
621 return BLK_STS_IOERR;
622 }
623}
624
625/**
626 * scsi_rq_err_bytes - determine number of bytes till the next failure boundary
627 * @rq: request to examine
628 *
629 * Description:
630 * A request could be merge of IOs which require different failure
631 * handling. This function determines the number of bytes which
632 * can be failed from the beginning of the request without
633 * crossing into area which need to be retried further.
634 *
635 * Return:
636 * The number of bytes to fail.
637 */
638static unsigned int scsi_rq_err_bytes(const struct request *rq)
639{
640 blk_opf_t ff = rq->cmd_flags & REQ_FAILFAST_MASK;
641 unsigned int bytes = 0;
642 struct bio *bio;
643
644 if (!(rq->rq_flags & RQF_MIXED_MERGE))
645 return blk_rq_bytes(rq);
646
647 /*
648 * Currently the only 'mixing' which can happen is between
649 * different fastfail types. We can safely fail portions
650 * which have all the failfast bits that the first one has -
651 * the ones which are at least as eager to fail as the first
652 * one.
653 */
654 for (bio = rq->bio; bio; bio = bio->bi_next) {
655 if ((bio->bi_opf & ff) != ff)
656 break;
657 bytes += bio->bi_iter.bi_size;
658 }
659
660 /* this could lead to infinite loop */
661 BUG_ON(blk_rq_bytes(rq) && !bytes);
662 return bytes;
663}
664
665static bool scsi_cmd_runtime_exceeced(struct scsi_cmnd *cmd)
666{
667 struct request *req = scsi_cmd_to_rq(cmd);
668 unsigned long wait_for;
669
670 if (cmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT)
671 return false;
672
673 wait_for = (cmd->allowed + 1) * req->timeout;
674 if (time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
675 scmd_printk(KERN_ERR, cmd, "timing out command, waited %lus\n",
676 wait_for/HZ);
677 return true;
678 }
679 return false;
680}
681
682/*
683 * When ALUA transition state is returned, reprep the cmd to
684 * use the ALUA handler's transition timeout. Delay the reprep
685 * 1 sec to avoid aggressive retries of the target in that
686 * state.
687 */
688#define ALUA_TRANSITION_REPREP_DELAY 1000
689
690/* Helper for scsi_io_completion() when special action required. */
691static void scsi_io_completion_action(struct scsi_cmnd *cmd, int result)
692{
693 struct request *req = scsi_cmd_to_rq(cmd);
694 int level = 0;
695 enum {ACTION_FAIL, ACTION_REPREP, ACTION_DELAYED_REPREP,
696 ACTION_RETRY, ACTION_DELAYED_RETRY} action;
697 struct scsi_sense_hdr sshdr;
698 bool sense_valid;
699 bool sense_current = true; /* false implies "deferred sense" */
700 blk_status_t blk_stat;
701
702 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
703 if (sense_valid)
704 sense_current = !scsi_sense_is_deferred(&sshdr);
705
706 blk_stat = scsi_result_to_blk_status(result);
707
708 if (host_byte(result) == DID_RESET) {
709 /* Third party bus reset or reset for error recovery
710 * reasons. Just retry the command and see what
711 * happens.
712 */
713 action = ACTION_RETRY;
714 } else if (sense_valid && sense_current) {
715 switch (sshdr.sense_key) {
716 case UNIT_ATTENTION:
717 if (cmd->device->removable) {
718 /* Detected disc change. Set a bit
719 * and quietly refuse further access.
720 */
721 cmd->device->changed = 1;
722 action = ACTION_FAIL;
723 } else {
724 /* Must have been a power glitch, or a
725 * bus reset. Could not have been a
726 * media change, so we just retry the
727 * command and see what happens.
728 */
729 action = ACTION_RETRY;
730 }
731 break;
732 case ILLEGAL_REQUEST:
733 /* If we had an ILLEGAL REQUEST returned, then
734 * we may have performed an unsupported
735 * command. The only thing this should be
736 * would be a ten byte read where only a six
737 * byte read was supported. Also, on a system
738 * where READ CAPACITY failed, we may have
739 * read past the end of the disk.
740 */
741 if ((cmd->device->use_10_for_rw &&
742 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
743 (cmd->cmnd[0] == READ_10 ||
744 cmd->cmnd[0] == WRITE_10)) {
745 /* This will issue a new 6-byte command. */
746 cmd->device->use_10_for_rw = 0;
747 action = ACTION_REPREP;
748 } else if (sshdr.asc == 0x10) /* DIX */ {
749 action = ACTION_FAIL;
750 blk_stat = BLK_STS_PROTECTION;
751 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
752 } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
753 action = ACTION_FAIL;
754 blk_stat = BLK_STS_TARGET;
755 } else
756 action = ACTION_FAIL;
757 break;
758 case ABORTED_COMMAND:
759 action = ACTION_FAIL;
760 if (sshdr.asc == 0x10) /* DIF */
761 blk_stat = BLK_STS_PROTECTION;
762 break;
763 case NOT_READY:
764 /* If the device is in the process of becoming
765 * ready, or has a temporary blockage, retry.
766 */
767 if (sshdr.asc == 0x04) {
768 switch (sshdr.ascq) {
769 case 0x01: /* becoming ready */
770 case 0x04: /* format in progress */
771 case 0x05: /* rebuild in progress */
772 case 0x06: /* recalculation in progress */
773 case 0x07: /* operation in progress */
774 case 0x08: /* Long write in progress */
775 case 0x09: /* self test in progress */
776 case 0x11: /* notify (enable spinup) required */
777 case 0x14: /* space allocation in progress */
778 case 0x1a: /* start stop unit in progress */
779 case 0x1b: /* sanitize in progress */
780 case 0x1d: /* configuration in progress */
781 case 0x24: /* depopulation in progress */
782 action = ACTION_DELAYED_RETRY;
783 break;
784 case 0x0a: /* ALUA state transition */
785 action = ACTION_DELAYED_REPREP;
786 break;
787 default:
788 action = ACTION_FAIL;
789 break;
790 }
791 } else
792 action = ACTION_FAIL;
793 break;
794 case VOLUME_OVERFLOW:
795 /* See SSC3rXX or current. */
796 action = ACTION_FAIL;
797 break;
798 case DATA_PROTECT:
799 action = ACTION_FAIL;
800 if ((sshdr.asc == 0x0C && sshdr.ascq == 0x12) ||
801 (sshdr.asc == 0x55 &&
802 (sshdr.ascq == 0x0E || sshdr.ascq == 0x0F))) {
803 /* Insufficient zone resources */
804 blk_stat = BLK_STS_ZONE_OPEN_RESOURCE;
805 }
806 break;
807 default:
808 action = ACTION_FAIL;
809 break;
810 }
811 } else
812 action = ACTION_FAIL;
813
814 if (action != ACTION_FAIL && scsi_cmd_runtime_exceeced(cmd))
815 action = ACTION_FAIL;
816
817 switch (action) {
818 case ACTION_FAIL:
819 /* Give up and fail the remainder of the request */
820 if (!(req->rq_flags & RQF_QUIET)) {
821 static DEFINE_RATELIMIT_STATE(_rs,
822 DEFAULT_RATELIMIT_INTERVAL,
823 DEFAULT_RATELIMIT_BURST);
824
825 if (unlikely(scsi_logging_level))
826 level =
827 SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
828 SCSI_LOG_MLCOMPLETE_BITS);
829
830 /*
831 * if logging is enabled the failure will be printed
832 * in scsi_log_completion(), so avoid duplicate messages
833 */
834 if (!level && __ratelimit(&_rs)) {
835 scsi_print_result(cmd, NULL, FAILED);
836 if (sense_valid)
837 scsi_print_sense(cmd);
838 scsi_print_command(cmd);
839 }
840 }
841 if (!scsi_end_request(req, blk_stat, scsi_rq_err_bytes(req)))
842 return;
843 fallthrough;
844 case ACTION_REPREP:
845 scsi_mq_requeue_cmd(cmd, 0);
846 break;
847 case ACTION_DELAYED_REPREP:
848 scsi_mq_requeue_cmd(cmd, ALUA_TRANSITION_REPREP_DELAY);
849 break;
850 case ACTION_RETRY:
851 /* Retry the same command immediately */
852 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, false);
853 break;
854 case ACTION_DELAYED_RETRY:
855 /* Retry the same command after a delay */
856 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, false);
857 break;
858 }
859}
860
861/*
862 * Helper for scsi_io_completion() when cmd->result is non-zero. Returns a
863 * new result that may suppress further error checking. Also modifies
864 * *blk_statp in some cases.
865 */
866static int scsi_io_completion_nz_result(struct scsi_cmnd *cmd, int result,
867 blk_status_t *blk_statp)
868{
869 bool sense_valid;
870 bool sense_current = true; /* false implies "deferred sense" */
871 struct request *req = scsi_cmd_to_rq(cmd);
872 struct scsi_sense_hdr sshdr;
873
874 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
875 if (sense_valid)
876 sense_current = !scsi_sense_is_deferred(&sshdr);
877
878 if (blk_rq_is_passthrough(req)) {
879 if (sense_valid) {
880 /*
881 * SG_IO wants current and deferred errors
882 */
883 cmd->sense_len = min(8 + cmd->sense_buffer[7],
884 SCSI_SENSE_BUFFERSIZE);
885 }
886 if (sense_current)
887 *blk_statp = scsi_result_to_blk_status(result);
888 } else if (blk_rq_bytes(req) == 0 && sense_current) {
889 /*
890 * Flush commands do not transfers any data, and thus cannot use
891 * good_bytes != blk_rq_bytes(req) as the signal for an error.
892 * This sets *blk_statp explicitly for the problem case.
893 */
894 *blk_statp = scsi_result_to_blk_status(result);
895 }
896 /*
897 * Recovered errors need reporting, but they're always treated as
898 * success, so fiddle the result code here. For passthrough requests
899 * we already took a copy of the original into sreq->result which
900 * is what gets returned to the user
901 */
902 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
903 bool do_print = true;
904 /*
905 * if ATA PASS-THROUGH INFORMATION AVAILABLE [0x0, 0x1d]
906 * skip print since caller wants ATA registers. Only occurs
907 * on SCSI ATA PASS_THROUGH commands when CK_COND=1
908 */
909 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
910 do_print = false;
911 else if (req->rq_flags & RQF_QUIET)
912 do_print = false;
913 if (do_print)
914 scsi_print_sense(cmd);
915 result = 0;
916 /* for passthrough, *blk_statp may be set */
917 *blk_statp = BLK_STS_OK;
918 }
919 /*
920 * Another corner case: the SCSI status byte is non-zero but 'good'.
921 * Example: PRE-FETCH command returns SAM_STAT_CONDITION_MET when
922 * it is able to fit nominated LBs in its cache (and SAM_STAT_GOOD
923 * if it can't fit). Treat SAM_STAT_CONDITION_MET and the related
924 * intermediate statuses (both obsolete in SAM-4) as good.
925 */
926 if ((result & 0xff) && scsi_status_is_good(result)) {
927 result = 0;
928 *blk_statp = BLK_STS_OK;
929 }
930 return result;
931}
932
933/**
934 * scsi_io_completion - Completion processing for SCSI commands.
935 * @cmd: command that is finished.
936 * @good_bytes: number of processed bytes.
937 *
938 * We will finish off the specified number of sectors. If we are done, the
939 * command block will be released and the queue function will be goosed. If we
940 * are not done then we have to figure out what to do next:
941 *
942 * a) We can call scsi_mq_requeue_cmd(). The request will be
943 * unprepared and put back on the queue. Then a new command will
944 * be created for it. This should be used if we made forward
945 * progress, or if we want to switch from READ(10) to READ(6) for
946 * example.
947 *
948 * b) We can call scsi_io_completion_action(). The request will be
949 * put back on the queue and retried using the same command as
950 * before, possibly after a delay.
951 *
952 * c) We can call scsi_end_request() with blk_stat other than
953 * BLK_STS_OK, to fail the remainder of the request.
954 */
955void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
956{
957 int result = cmd->result;
958 struct request *req = scsi_cmd_to_rq(cmd);
959 blk_status_t blk_stat = BLK_STS_OK;
960
961 if (unlikely(result)) /* a nz result may or may not be an error */
962 result = scsi_io_completion_nz_result(cmd, result, &blk_stat);
963
964 /*
965 * Next deal with any sectors which we were able to correctly
966 * handle.
967 */
968 SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd,
969 "%u sectors total, %d bytes done.\n",
970 blk_rq_sectors(req), good_bytes));
971
972 /*
973 * Failed, zero length commands always need to drop down
974 * to retry code. Fast path should return in this block.
975 */
976 if (likely(blk_rq_bytes(req) > 0 || blk_stat == BLK_STS_OK)) {
977 if (likely(!scsi_end_request(req, blk_stat, good_bytes)))
978 return; /* no bytes remaining */
979 }
980
981 /* Kill remainder if no retries. */
982 if (unlikely(blk_stat && scsi_noretry_cmd(cmd))) {
983 if (scsi_end_request(req, blk_stat, blk_rq_bytes(req)))
984 WARN_ONCE(true,
985 "Bytes remaining after failed, no-retry command");
986 return;
987 }
988
989 /*
990 * If there had been no error, but we have leftover bytes in the
991 * request just queue the command up again.
992 */
993 if (likely(result == 0))
994 scsi_mq_requeue_cmd(cmd, 0);
995 else
996 scsi_io_completion_action(cmd, result);
997}
998
999static inline bool scsi_cmd_needs_dma_drain(struct scsi_device *sdev,
1000 struct request *rq)
1001{
1002 return sdev->dma_drain_len && blk_rq_is_passthrough(rq) &&
1003 !op_is_write(req_op(rq)) &&
1004 sdev->host->hostt->dma_need_drain(rq);
1005}
1006
1007/**
1008 * scsi_alloc_sgtables - Allocate and initialize data and integrity scatterlists
1009 * @cmd: SCSI command data structure to initialize.
1010 *
1011 * Initializes @cmd->sdb and also @cmd->prot_sdb if data integrity is enabled
1012 * for @cmd.
1013 *
1014 * Returns:
1015 * * BLK_STS_OK - on success
1016 * * BLK_STS_RESOURCE - if the failure is retryable
1017 * * BLK_STS_IOERR - if the failure is fatal
1018 */
1019blk_status_t scsi_alloc_sgtables(struct scsi_cmnd *cmd)
1020{
1021 struct scsi_device *sdev = cmd->device;
1022 struct request *rq = scsi_cmd_to_rq(cmd);
1023 unsigned short nr_segs = blk_rq_nr_phys_segments(rq);
1024 struct scatterlist *last_sg = NULL;
1025 blk_status_t ret;
1026 bool need_drain = scsi_cmd_needs_dma_drain(sdev, rq);
1027 int count;
1028
1029 if (WARN_ON_ONCE(!nr_segs))
1030 return BLK_STS_IOERR;
1031
1032 /*
1033 * Make sure there is space for the drain. The driver must adjust
1034 * max_hw_segments to be prepared for this.
1035 */
1036 if (need_drain)
1037 nr_segs++;
1038
1039 /*
1040 * If sg table allocation fails, requeue request later.
1041 */
1042 if (unlikely(sg_alloc_table_chained(&cmd->sdb.table, nr_segs,
1043 cmd->sdb.table.sgl, SCSI_INLINE_SG_CNT)))
1044 return BLK_STS_RESOURCE;
1045
1046 /*
1047 * Next, walk the list, and fill in the addresses and sizes of
1048 * each segment.
1049 */
1050 count = __blk_rq_map_sg(rq->q, rq, cmd->sdb.table.sgl, &last_sg);
1051
1052 if (blk_rq_bytes(rq) & rq->q->dma_pad_mask) {
1053 unsigned int pad_len =
1054 (rq->q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1;
1055
1056 last_sg->length += pad_len;
1057 cmd->extra_len += pad_len;
1058 }
1059
1060 if (need_drain) {
1061 sg_unmark_end(last_sg);
1062 last_sg = sg_next(last_sg);
1063 sg_set_buf(last_sg, sdev->dma_drain_buf, sdev->dma_drain_len);
1064 sg_mark_end(last_sg);
1065
1066 cmd->extra_len += sdev->dma_drain_len;
1067 count++;
1068 }
1069
1070 BUG_ON(count > cmd->sdb.table.nents);
1071 cmd->sdb.table.nents = count;
1072 cmd->sdb.length = blk_rq_payload_bytes(rq);
1073
1074 if (blk_integrity_rq(rq)) {
1075 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1076 int ivecs;
1077
1078 if (WARN_ON_ONCE(!prot_sdb)) {
1079 /*
1080 * This can happen if someone (e.g. multipath)
1081 * queues a command to a device on an adapter
1082 * that does not support DIX.
1083 */
1084 ret = BLK_STS_IOERR;
1085 goto out_free_sgtables;
1086 }
1087
1088 ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
1089
1090 if (sg_alloc_table_chained(&prot_sdb->table, ivecs,
1091 prot_sdb->table.sgl,
1092 SCSI_INLINE_PROT_SG_CNT)) {
1093 ret = BLK_STS_RESOURCE;
1094 goto out_free_sgtables;
1095 }
1096
1097 count = blk_rq_map_integrity_sg(rq->q, rq->bio,
1098 prot_sdb->table.sgl);
1099 BUG_ON(count > ivecs);
1100 BUG_ON(count > queue_max_integrity_segments(rq->q));
1101
1102 cmd->prot_sdb = prot_sdb;
1103 cmd->prot_sdb->table.nents = count;
1104 }
1105
1106 return BLK_STS_OK;
1107out_free_sgtables:
1108 scsi_free_sgtables(cmd);
1109 return ret;
1110}
1111EXPORT_SYMBOL(scsi_alloc_sgtables);
1112
1113/**
1114 * scsi_initialize_rq - initialize struct scsi_cmnd partially
1115 * @rq: Request associated with the SCSI command to be initialized.
1116 *
1117 * This function initializes the members of struct scsi_cmnd that must be
1118 * initialized before request processing starts and that won't be
1119 * reinitialized if a SCSI command is requeued.
1120 */
1121static void scsi_initialize_rq(struct request *rq)
1122{
1123 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1124
1125 memset(cmd->cmnd, 0, sizeof(cmd->cmnd));
1126 cmd->cmd_len = MAX_COMMAND_SIZE;
1127 cmd->sense_len = 0;
1128 init_rcu_head(&cmd->rcu);
1129 cmd->jiffies_at_alloc = jiffies;
1130 cmd->retries = 0;
1131}
1132
1133struct request *scsi_alloc_request(struct request_queue *q, blk_opf_t opf,
1134 blk_mq_req_flags_t flags)
1135{
1136 struct request *rq;
1137
1138 rq = blk_mq_alloc_request(q, opf, flags);
1139 if (!IS_ERR(rq))
1140 scsi_initialize_rq(rq);
1141 return rq;
1142}
1143EXPORT_SYMBOL_GPL(scsi_alloc_request);
1144
1145/*
1146 * Only called when the request isn't completed by SCSI, and not freed by
1147 * SCSI
1148 */
1149static void scsi_cleanup_rq(struct request *rq)
1150{
1151 if (rq->rq_flags & RQF_DONTPREP) {
1152 scsi_mq_uninit_cmd(blk_mq_rq_to_pdu(rq));
1153 rq->rq_flags &= ~RQF_DONTPREP;
1154 }
1155}
1156
1157/* Called before a request is prepared. See also scsi_mq_prep_fn(). */
1158void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd)
1159{
1160 struct request *rq = scsi_cmd_to_rq(cmd);
1161
1162 if (!blk_rq_is_passthrough(rq) && !(cmd->flags & SCMD_INITIALIZED)) {
1163 cmd->flags |= SCMD_INITIALIZED;
1164 scsi_initialize_rq(rq);
1165 }
1166
1167 cmd->device = dev;
1168 INIT_LIST_HEAD(&cmd->eh_entry);
1169 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
1170}
1171
1172static blk_status_t scsi_setup_scsi_cmnd(struct scsi_device *sdev,
1173 struct request *req)
1174{
1175 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1176
1177 /*
1178 * Passthrough requests may transfer data, in which case they must
1179 * a bio attached to them. Or they might contain a SCSI command
1180 * that does not transfer data, in which case they may optionally
1181 * submit a request without an attached bio.
1182 */
1183 if (req->bio) {
1184 blk_status_t ret = scsi_alloc_sgtables(cmd);
1185 if (unlikely(ret != BLK_STS_OK))
1186 return ret;
1187 } else {
1188 BUG_ON(blk_rq_bytes(req));
1189
1190 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1191 }
1192
1193 cmd->transfersize = blk_rq_bytes(req);
1194 return BLK_STS_OK;
1195}
1196
1197static blk_status_t
1198scsi_device_state_check(struct scsi_device *sdev, struct request *req)
1199{
1200 switch (sdev->sdev_state) {
1201 case SDEV_CREATED:
1202 return BLK_STS_OK;
1203 case SDEV_OFFLINE:
1204 case SDEV_TRANSPORT_OFFLINE:
1205 /*
1206 * If the device is offline we refuse to process any
1207 * commands. The device must be brought online
1208 * before trying any recovery commands.
1209 */
1210 if (!sdev->offline_already) {
1211 sdev->offline_already = true;
1212 sdev_printk(KERN_ERR, sdev,
1213 "rejecting I/O to offline device\n");
1214 }
1215 return BLK_STS_IOERR;
1216 case SDEV_DEL:
1217 /*
1218 * If the device is fully deleted, we refuse to
1219 * process any commands as well.
1220 */
1221 sdev_printk(KERN_ERR, sdev,
1222 "rejecting I/O to dead device\n");
1223 return BLK_STS_IOERR;
1224 case SDEV_BLOCK:
1225 case SDEV_CREATED_BLOCK:
1226 return BLK_STS_RESOURCE;
1227 case SDEV_QUIESCE:
1228 /*
1229 * If the device is blocked we only accept power management
1230 * commands.
1231 */
1232 if (req && WARN_ON_ONCE(!(req->rq_flags & RQF_PM)))
1233 return BLK_STS_RESOURCE;
1234 return BLK_STS_OK;
1235 default:
1236 /*
1237 * For any other not fully online state we only allow
1238 * power management commands.
1239 */
1240 if (req && !(req->rq_flags & RQF_PM))
1241 return BLK_STS_OFFLINE;
1242 return BLK_STS_OK;
1243 }
1244}
1245
1246/*
1247 * scsi_dev_queue_ready: if we can send requests to sdev, assign one token
1248 * and return the token else return -1.
1249 */
1250static inline int scsi_dev_queue_ready(struct request_queue *q,
1251 struct scsi_device *sdev)
1252{
1253 int token;
1254
1255 token = sbitmap_get(&sdev->budget_map);
1256 if (atomic_read(&sdev->device_blocked)) {
1257 if (token < 0)
1258 goto out;
1259
1260 if (scsi_device_busy(sdev) > 1)
1261 goto out_dec;
1262
1263 /*
1264 * unblock after device_blocked iterates to zero
1265 */
1266 if (atomic_dec_return(&sdev->device_blocked) > 0)
1267 goto out_dec;
1268 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev,
1269 "unblocking device at zero depth\n"));
1270 }
1271
1272 return token;
1273out_dec:
1274 if (token >= 0)
1275 sbitmap_put(&sdev->budget_map, token);
1276out:
1277 return -1;
1278}
1279
1280/*
1281 * scsi_target_queue_ready: checks if there we can send commands to target
1282 * @sdev: scsi device on starget to check.
1283 */
1284static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1285 struct scsi_device *sdev)
1286{
1287 struct scsi_target *starget = scsi_target(sdev);
1288 unsigned int busy;
1289
1290 if (starget->single_lun) {
1291 spin_lock_irq(shost->host_lock);
1292 if (starget->starget_sdev_user &&
1293 starget->starget_sdev_user != sdev) {
1294 spin_unlock_irq(shost->host_lock);
1295 return 0;
1296 }
1297 starget->starget_sdev_user = sdev;
1298 spin_unlock_irq(shost->host_lock);
1299 }
1300
1301 if (starget->can_queue <= 0)
1302 return 1;
1303
1304 busy = atomic_inc_return(&starget->target_busy) - 1;
1305 if (atomic_read(&starget->target_blocked) > 0) {
1306 if (busy)
1307 goto starved;
1308
1309 /*
1310 * unblock after target_blocked iterates to zero
1311 */
1312 if (atomic_dec_return(&starget->target_blocked) > 0)
1313 goto out_dec;
1314
1315 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1316 "unblocking target at zero depth\n"));
1317 }
1318
1319 if (busy >= starget->can_queue)
1320 goto starved;
1321
1322 return 1;
1323
1324starved:
1325 spin_lock_irq(shost->host_lock);
1326 list_move_tail(&sdev->starved_entry, &shost->starved_list);
1327 spin_unlock_irq(shost->host_lock);
1328out_dec:
1329 if (starget->can_queue > 0)
1330 atomic_dec(&starget->target_busy);
1331 return 0;
1332}
1333
1334/*
1335 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1336 * return 0. We must end up running the queue again whenever 0 is
1337 * returned, else IO can hang.
1338 */
1339static inline int scsi_host_queue_ready(struct request_queue *q,
1340 struct Scsi_Host *shost,
1341 struct scsi_device *sdev,
1342 struct scsi_cmnd *cmd)
1343{
1344 if (atomic_read(&shost->host_blocked) > 0) {
1345 if (scsi_host_busy(shost) > 0)
1346 goto starved;
1347
1348 /*
1349 * unblock after host_blocked iterates to zero
1350 */
1351 if (atomic_dec_return(&shost->host_blocked) > 0)
1352 goto out_dec;
1353
1354 SCSI_LOG_MLQUEUE(3,
1355 shost_printk(KERN_INFO, shost,
1356 "unblocking host at zero depth\n"));
1357 }
1358
1359 if (shost->host_self_blocked)
1360 goto starved;
1361
1362 /* We're OK to process the command, so we can't be starved */
1363 if (!list_empty(&sdev->starved_entry)) {
1364 spin_lock_irq(shost->host_lock);
1365 if (!list_empty(&sdev->starved_entry))
1366 list_del_init(&sdev->starved_entry);
1367 spin_unlock_irq(shost->host_lock);
1368 }
1369
1370 __set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1371
1372 return 1;
1373
1374starved:
1375 spin_lock_irq(shost->host_lock);
1376 if (list_empty(&sdev->starved_entry))
1377 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1378 spin_unlock_irq(shost->host_lock);
1379out_dec:
1380 scsi_dec_host_busy(shost, cmd);
1381 return 0;
1382}
1383
1384/*
1385 * Busy state exporting function for request stacking drivers.
1386 *
1387 * For efficiency, no lock is taken to check the busy state of
1388 * shost/starget/sdev, since the returned value is not guaranteed and
1389 * may be changed after request stacking drivers call the function,
1390 * regardless of taking lock or not.
1391 *
1392 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1393 * needs to return 'not busy'. Otherwise, request stacking drivers
1394 * may hold requests forever.
1395 */
1396static bool scsi_mq_lld_busy(struct request_queue *q)
1397{
1398 struct scsi_device *sdev = q->queuedata;
1399 struct Scsi_Host *shost;
1400
1401 if (blk_queue_dying(q))
1402 return false;
1403
1404 shost = sdev->host;
1405
1406 /*
1407 * Ignore host/starget busy state.
1408 * Since block layer does not have a concept of fairness across
1409 * multiple queues, congestion of host/starget needs to be handled
1410 * in SCSI layer.
1411 */
1412 if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
1413 return true;
1414
1415 return false;
1416}
1417
1418/*
1419 * Block layer request completion callback. May be called from interrupt
1420 * context.
1421 */
1422static void scsi_complete(struct request *rq)
1423{
1424 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1425 enum scsi_disposition disposition;
1426
1427 INIT_LIST_HEAD(&cmd->eh_entry);
1428
1429 atomic_inc(&cmd->device->iodone_cnt);
1430 if (cmd->result)
1431 atomic_inc(&cmd->device->ioerr_cnt);
1432
1433 disposition = scsi_decide_disposition(cmd);
1434 if (disposition != SUCCESS && scsi_cmd_runtime_exceeced(cmd))
1435 disposition = SUCCESS;
1436
1437 scsi_log_completion(cmd, disposition);
1438
1439 switch (disposition) {
1440 case SUCCESS:
1441 scsi_finish_command(cmd);
1442 break;
1443 case NEEDS_RETRY:
1444 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
1445 break;
1446 case ADD_TO_MLQUEUE:
1447 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1448 break;
1449 default:
1450 scsi_eh_scmd_add(cmd);
1451 break;
1452 }
1453}
1454
1455/**
1456 * scsi_dispatch_cmd - Dispatch a command to the low-level driver.
1457 * @cmd: command block we are dispatching.
1458 *
1459 * Return: nonzero return request was rejected and device's queue needs to be
1460 * plugged.
1461 */
1462static int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
1463{
1464 struct Scsi_Host *host = cmd->device->host;
1465 int rtn = 0;
1466
1467 /* check if the device is still usable */
1468 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
1469 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
1470 * returns an immediate error upwards, and signals
1471 * that the device is no longer present */
1472 cmd->result = DID_NO_CONNECT << 16;
1473 goto done;
1474 }
1475
1476 /* Check to see if the scsi lld made this device blocked. */
1477 if (unlikely(scsi_device_blocked(cmd->device))) {
1478 /*
1479 * in blocked state, the command is just put back on
1480 * the device queue. The suspend state has already
1481 * blocked the queue so future requests should not
1482 * occur until the device transitions out of the
1483 * suspend state.
1484 */
1485 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1486 "queuecommand : device blocked\n"));
1487 return SCSI_MLQUEUE_DEVICE_BUSY;
1488 }
1489
1490 /* Store the LUN value in cmnd, if needed. */
1491 if (cmd->device->lun_in_cdb)
1492 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
1493 (cmd->device->lun << 5 & 0xe0);
1494
1495 scsi_log_send(cmd);
1496
1497 /*
1498 * Before we queue this command, check if the command
1499 * length exceeds what the host adapter can handle.
1500 */
1501 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
1502 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1503 "queuecommand : command too long. "
1504 "cdb_size=%d host->max_cmd_len=%d\n",
1505 cmd->cmd_len, cmd->device->host->max_cmd_len));
1506 cmd->result = (DID_ABORT << 16);
1507 goto done;
1508 }
1509
1510 if (unlikely(host->shost_state == SHOST_DEL)) {
1511 cmd->result = (DID_NO_CONNECT << 16);
1512 goto done;
1513
1514 }
1515
1516 trace_scsi_dispatch_cmd_start(cmd);
1517 rtn = host->hostt->queuecommand(host, cmd);
1518 if (rtn) {
1519 trace_scsi_dispatch_cmd_error(cmd, rtn);
1520 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
1521 rtn != SCSI_MLQUEUE_TARGET_BUSY)
1522 rtn = SCSI_MLQUEUE_HOST_BUSY;
1523
1524 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1525 "queuecommand : request rejected\n"));
1526 }
1527
1528 return rtn;
1529 done:
1530 scsi_done(cmd);
1531 return 0;
1532}
1533
1534/* Size in bytes of the sg-list stored in the scsi-mq command-private data. */
1535static unsigned int scsi_mq_inline_sgl_size(struct Scsi_Host *shost)
1536{
1537 return min_t(unsigned int, shost->sg_tablesize, SCSI_INLINE_SG_CNT) *
1538 sizeof(struct scatterlist);
1539}
1540
1541static blk_status_t scsi_prepare_cmd(struct request *req)
1542{
1543 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1544 struct scsi_device *sdev = req->q->queuedata;
1545 struct Scsi_Host *shost = sdev->host;
1546 bool in_flight = test_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1547 struct scatterlist *sg;
1548
1549 scsi_init_command(sdev, cmd);
1550
1551 cmd->eh_eflags = 0;
1552 cmd->prot_type = 0;
1553 cmd->prot_flags = 0;
1554 cmd->submitter = 0;
1555 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1556 cmd->underflow = 0;
1557 cmd->transfersize = 0;
1558 cmd->host_scribble = NULL;
1559 cmd->result = 0;
1560 cmd->extra_len = 0;
1561 cmd->state = 0;
1562 if (in_flight)
1563 __set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1564
1565 /*
1566 * Only clear the driver-private command data if the LLD does not supply
1567 * a function to initialize that data.
1568 */
1569 if (!shost->hostt->init_cmd_priv)
1570 memset(cmd + 1, 0, shost->hostt->cmd_size);
1571
1572 cmd->prot_op = SCSI_PROT_NORMAL;
1573 if (blk_rq_bytes(req))
1574 cmd->sc_data_direction = rq_dma_dir(req);
1575 else
1576 cmd->sc_data_direction = DMA_NONE;
1577
1578 sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
1579 cmd->sdb.table.sgl = sg;
1580
1581 if (scsi_host_get_prot(shost)) {
1582 memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer));
1583
1584 cmd->prot_sdb->table.sgl =
1585 (struct scatterlist *)(cmd->prot_sdb + 1);
1586 }
1587
1588 /*
1589 * Special handling for passthrough commands, which don't go to the ULP
1590 * at all:
1591 */
1592 if (blk_rq_is_passthrough(req))
1593 return scsi_setup_scsi_cmnd(sdev, req);
1594
1595 if (sdev->handler && sdev->handler->prep_fn) {
1596 blk_status_t ret = sdev->handler->prep_fn(sdev, req);
1597
1598 if (ret != BLK_STS_OK)
1599 return ret;
1600 }
1601
1602 /* Usually overridden by the ULP */
1603 cmd->allowed = 0;
1604 memset(cmd->cmnd, 0, sizeof(cmd->cmnd));
1605 return scsi_cmd_to_driver(cmd)->init_command(cmd);
1606}
1607
1608static void scsi_done_internal(struct scsi_cmnd *cmd, bool complete_directly)
1609{
1610 struct request *req = scsi_cmd_to_rq(cmd);
1611
1612 switch (cmd->submitter) {
1613 case SUBMITTED_BY_BLOCK_LAYER:
1614 break;
1615 case SUBMITTED_BY_SCSI_ERROR_HANDLER:
1616 return scsi_eh_done(cmd);
1617 case SUBMITTED_BY_SCSI_RESET_IOCTL:
1618 return;
1619 }
1620
1621 if (unlikely(blk_should_fake_timeout(scsi_cmd_to_rq(cmd)->q)))
1622 return;
1623 if (unlikely(test_and_set_bit(SCMD_STATE_COMPLETE, &cmd->state)))
1624 return;
1625 trace_scsi_dispatch_cmd_done(cmd);
1626
1627 if (complete_directly)
1628 blk_mq_complete_request_direct(req, scsi_complete);
1629 else
1630 blk_mq_complete_request(req);
1631}
1632
1633void scsi_done(struct scsi_cmnd *cmd)
1634{
1635 scsi_done_internal(cmd, false);
1636}
1637EXPORT_SYMBOL(scsi_done);
1638
1639void scsi_done_direct(struct scsi_cmnd *cmd)
1640{
1641 scsi_done_internal(cmd, true);
1642}
1643EXPORT_SYMBOL(scsi_done_direct);
1644
1645static void scsi_mq_put_budget(struct request_queue *q, int budget_token)
1646{
1647 struct scsi_device *sdev = q->queuedata;
1648
1649 sbitmap_put(&sdev->budget_map, budget_token);
1650}
1651
1652/*
1653 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
1654 * not change behaviour from the previous unplug mechanism, experimentation
1655 * may prove this needs changing.
1656 */
1657#define SCSI_QUEUE_DELAY 3
1658
1659static int scsi_mq_get_budget(struct request_queue *q)
1660{
1661 struct scsi_device *sdev = q->queuedata;
1662 int token = scsi_dev_queue_ready(q, sdev);
1663
1664 if (token >= 0)
1665 return token;
1666
1667 atomic_inc(&sdev->restarts);
1668
1669 /*
1670 * Orders atomic_inc(&sdev->restarts) and atomic_read(&sdev->device_busy).
1671 * .restarts must be incremented before .device_busy is read because the
1672 * code in scsi_run_queue_async() depends on the order of these operations.
1673 */
1674 smp_mb__after_atomic();
1675
1676 /*
1677 * If all in-flight requests originated from this LUN are completed
1678 * before reading .device_busy, sdev->device_busy will be observed as
1679 * zero, then blk_mq_delay_run_hw_queues() will dispatch this request
1680 * soon. Otherwise, completion of one of these requests will observe
1681 * the .restarts flag, and the request queue will be run for handling
1682 * this request, see scsi_end_request().
1683 */
1684 if (unlikely(scsi_device_busy(sdev) == 0 &&
1685 !scsi_device_blocked(sdev)))
1686 blk_mq_delay_run_hw_queues(sdev->request_queue, SCSI_QUEUE_DELAY);
1687 return -1;
1688}
1689
1690static void scsi_mq_set_rq_budget_token(struct request *req, int token)
1691{
1692 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1693
1694 cmd->budget_token = token;
1695}
1696
1697static int scsi_mq_get_rq_budget_token(struct request *req)
1698{
1699 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1700
1701 return cmd->budget_token;
1702}
1703
1704static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
1705 const struct blk_mq_queue_data *bd)
1706{
1707 struct request *req = bd->rq;
1708 struct request_queue *q = req->q;
1709 struct scsi_device *sdev = q->queuedata;
1710 struct Scsi_Host *shost = sdev->host;
1711 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1712 blk_status_t ret;
1713 int reason;
1714
1715 WARN_ON_ONCE(cmd->budget_token < 0);
1716
1717 /*
1718 * If the device is not in running state we will reject some or all
1719 * commands.
1720 */
1721 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
1722 ret = scsi_device_state_check(sdev, req);
1723 if (ret != BLK_STS_OK)
1724 goto out_put_budget;
1725 }
1726
1727 ret = BLK_STS_RESOURCE;
1728 if (!scsi_target_queue_ready(shost, sdev))
1729 goto out_put_budget;
1730 if (unlikely(scsi_host_in_recovery(shost))) {
1731 if (cmd->flags & SCMD_FAIL_IF_RECOVERING)
1732 ret = BLK_STS_OFFLINE;
1733 goto out_dec_target_busy;
1734 }
1735 if (!scsi_host_queue_ready(q, shost, sdev, cmd))
1736 goto out_dec_target_busy;
1737
1738 if (!(req->rq_flags & RQF_DONTPREP)) {
1739 ret = scsi_prepare_cmd(req);
1740 if (ret != BLK_STS_OK)
1741 goto out_dec_host_busy;
1742 req->rq_flags |= RQF_DONTPREP;
1743 } else {
1744 clear_bit(SCMD_STATE_COMPLETE, &cmd->state);
1745 }
1746
1747 cmd->flags &= SCMD_PRESERVED_FLAGS;
1748 if (sdev->simple_tags)
1749 cmd->flags |= SCMD_TAGGED;
1750 if (bd->last)
1751 cmd->flags |= SCMD_LAST;
1752
1753 scsi_set_resid(cmd, 0);
1754 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
1755 cmd->submitter = SUBMITTED_BY_BLOCK_LAYER;
1756
1757 blk_mq_start_request(req);
1758 reason = scsi_dispatch_cmd(cmd);
1759 if (reason) {
1760 scsi_set_blocked(cmd, reason);
1761 ret = BLK_STS_RESOURCE;
1762 goto out_dec_host_busy;
1763 }
1764
1765 atomic_inc(&cmd->device->iorequest_cnt);
1766 return BLK_STS_OK;
1767
1768out_dec_host_busy:
1769 scsi_dec_host_busy(shost, cmd);
1770out_dec_target_busy:
1771 if (scsi_target(sdev)->can_queue > 0)
1772 atomic_dec(&scsi_target(sdev)->target_busy);
1773out_put_budget:
1774 scsi_mq_put_budget(q, cmd->budget_token);
1775 cmd->budget_token = -1;
1776 switch (ret) {
1777 case BLK_STS_OK:
1778 break;
1779 case BLK_STS_RESOURCE:
1780 case BLK_STS_ZONE_RESOURCE:
1781 if (scsi_device_blocked(sdev))
1782 ret = BLK_STS_DEV_RESOURCE;
1783 break;
1784 case BLK_STS_AGAIN:
1785 cmd->result = DID_BUS_BUSY << 16;
1786 if (req->rq_flags & RQF_DONTPREP)
1787 scsi_mq_uninit_cmd(cmd);
1788 break;
1789 default:
1790 if (unlikely(!scsi_device_online(sdev)))
1791 cmd->result = DID_NO_CONNECT << 16;
1792 else
1793 cmd->result = DID_ERROR << 16;
1794 /*
1795 * Make sure to release all allocated resources when
1796 * we hit an error, as we will never see this command
1797 * again.
1798 */
1799 if (req->rq_flags & RQF_DONTPREP)
1800 scsi_mq_uninit_cmd(cmd);
1801 scsi_run_queue_async(sdev);
1802 break;
1803 }
1804 return ret;
1805}
1806
1807static int scsi_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
1808 unsigned int hctx_idx, unsigned int numa_node)
1809{
1810 struct Scsi_Host *shost = set->driver_data;
1811 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1812 struct scatterlist *sg;
1813 int ret = 0;
1814
1815 cmd->sense_buffer =
1816 kmem_cache_alloc_node(scsi_sense_cache, GFP_KERNEL, numa_node);
1817 if (!cmd->sense_buffer)
1818 return -ENOMEM;
1819
1820 if (scsi_host_get_prot(shost)) {
1821 sg = (void *)cmd + sizeof(struct scsi_cmnd) +
1822 shost->hostt->cmd_size;
1823 cmd->prot_sdb = (void *)sg + scsi_mq_inline_sgl_size(shost);
1824 }
1825
1826 if (shost->hostt->init_cmd_priv) {
1827 ret = shost->hostt->init_cmd_priv(shost, cmd);
1828 if (ret < 0)
1829 kmem_cache_free(scsi_sense_cache, cmd->sense_buffer);
1830 }
1831
1832 return ret;
1833}
1834
1835static void scsi_mq_exit_request(struct blk_mq_tag_set *set, struct request *rq,
1836 unsigned int hctx_idx)
1837{
1838 struct Scsi_Host *shost = set->driver_data;
1839 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1840
1841 if (shost->hostt->exit_cmd_priv)
1842 shost->hostt->exit_cmd_priv(shost, cmd);
1843 kmem_cache_free(scsi_sense_cache, cmd->sense_buffer);
1844}
1845
1846
1847static int scsi_mq_poll(struct blk_mq_hw_ctx *hctx, struct io_comp_batch *iob)
1848{
1849 struct Scsi_Host *shost = hctx->driver_data;
1850
1851 if (shost->hostt->mq_poll)
1852 return shost->hostt->mq_poll(shost, hctx->queue_num);
1853
1854 return 0;
1855}
1856
1857static int scsi_init_hctx(struct blk_mq_hw_ctx *hctx, void *data,
1858 unsigned int hctx_idx)
1859{
1860 struct Scsi_Host *shost = data;
1861
1862 hctx->driver_data = shost;
1863 return 0;
1864}
1865
1866static void scsi_map_queues(struct blk_mq_tag_set *set)
1867{
1868 struct Scsi_Host *shost = container_of(set, struct Scsi_Host, tag_set);
1869
1870 if (shost->hostt->map_queues)
1871 return shost->hostt->map_queues(shost);
1872 blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]);
1873}
1874
1875void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
1876{
1877 struct device *dev = shost->dma_dev;
1878
1879 /*
1880 * this limit is imposed by hardware restrictions
1881 */
1882 blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
1883 SG_MAX_SEGMENTS));
1884
1885 if (scsi_host_prot_dma(shost)) {
1886 shost->sg_prot_tablesize =
1887 min_not_zero(shost->sg_prot_tablesize,
1888 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
1889 BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
1890 blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
1891 }
1892
1893 blk_queue_max_hw_sectors(q, shost->max_sectors);
1894 blk_queue_segment_boundary(q, shost->dma_boundary);
1895 dma_set_seg_boundary(dev, shost->dma_boundary);
1896
1897 blk_queue_max_segment_size(q, shost->max_segment_size);
1898 blk_queue_virt_boundary(q, shost->virt_boundary_mask);
1899 dma_set_max_seg_size(dev, queue_max_segment_size(q));
1900
1901 /*
1902 * Set a reasonable default alignment: The larger of 32-byte (dword),
1903 * which is a common minimum for HBAs, and the minimum DMA alignment,
1904 * which is set by the platform.
1905 *
1906 * Devices that require a bigger alignment can increase it later.
1907 */
1908 blk_queue_dma_alignment(q, max(4, dma_get_cache_alignment()) - 1);
1909}
1910EXPORT_SYMBOL_GPL(__scsi_init_queue);
1911
1912static const struct blk_mq_ops scsi_mq_ops_no_commit = {
1913 .get_budget = scsi_mq_get_budget,
1914 .put_budget = scsi_mq_put_budget,
1915 .queue_rq = scsi_queue_rq,
1916 .complete = scsi_complete,
1917 .timeout = scsi_timeout,
1918#ifdef CONFIG_BLK_DEBUG_FS
1919 .show_rq = scsi_show_rq,
1920#endif
1921 .init_request = scsi_mq_init_request,
1922 .exit_request = scsi_mq_exit_request,
1923 .cleanup_rq = scsi_cleanup_rq,
1924 .busy = scsi_mq_lld_busy,
1925 .map_queues = scsi_map_queues,
1926 .init_hctx = scsi_init_hctx,
1927 .poll = scsi_mq_poll,
1928 .set_rq_budget_token = scsi_mq_set_rq_budget_token,
1929 .get_rq_budget_token = scsi_mq_get_rq_budget_token,
1930};
1931
1932
1933static void scsi_commit_rqs(struct blk_mq_hw_ctx *hctx)
1934{
1935 struct Scsi_Host *shost = hctx->driver_data;
1936
1937 shost->hostt->commit_rqs(shost, hctx->queue_num);
1938}
1939
1940static const struct blk_mq_ops scsi_mq_ops = {
1941 .get_budget = scsi_mq_get_budget,
1942 .put_budget = scsi_mq_put_budget,
1943 .queue_rq = scsi_queue_rq,
1944 .commit_rqs = scsi_commit_rqs,
1945 .complete = scsi_complete,
1946 .timeout = scsi_timeout,
1947#ifdef CONFIG_BLK_DEBUG_FS
1948 .show_rq = scsi_show_rq,
1949#endif
1950 .init_request = scsi_mq_init_request,
1951 .exit_request = scsi_mq_exit_request,
1952 .cleanup_rq = scsi_cleanup_rq,
1953 .busy = scsi_mq_lld_busy,
1954 .map_queues = scsi_map_queues,
1955 .init_hctx = scsi_init_hctx,
1956 .poll = scsi_mq_poll,
1957 .set_rq_budget_token = scsi_mq_set_rq_budget_token,
1958 .get_rq_budget_token = scsi_mq_get_rq_budget_token,
1959};
1960
1961int scsi_mq_setup_tags(struct Scsi_Host *shost)
1962{
1963 unsigned int cmd_size, sgl_size;
1964 struct blk_mq_tag_set *tag_set = &shost->tag_set;
1965
1966 sgl_size = max_t(unsigned int, sizeof(struct scatterlist),
1967 scsi_mq_inline_sgl_size(shost));
1968 cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size;
1969 if (scsi_host_get_prot(shost))
1970 cmd_size += sizeof(struct scsi_data_buffer) +
1971 sizeof(struct scatterlist) * SCSI_INLINE_PROT_SG_CNT;
1972
1973 memset(tag_set, 0, sizeof(*tag_set));
1974 if (shost->hostt->commit_rqs)
1975 tag_set->ops = &scsi_mq_ops;
1976 else
1977 tag_set->ops = &scsi_mq_ops_no_commit;
1978 tag_set->nr_hw_queues = shost->nr_hw_queues ? : 1;
1979 tag_set->nr_maps = shost->nr_maps ? : 1;
1980 tag_set->queue_depth = shost->can_queue;
1981 tag_set->cmd_size = cmd_size;
1982 tag_set->numa_node = dev_to_node(shost->dma_dev);
1983 tag_set->flags = BLK_MQ_F_SHOULD_MERGE;
1984 tag_set->flags |=
1985 BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
1986 tag_set->driver_data = shost;
1987 if (shost->host_tagset)
1988 tag_set->flags |= BLK_MQ_F_TAG_HCTX_SHARED;
1989
1990 return blk_mq_alloc_tag_set(tag_set);
1991}
1992
1993void scsi_mq_free_tags(struct kref *kref)
1994{
1995 struct Scsi_Host *shost = container_of(kref, typeof(*shost),
1996 tagset_refcnt);
1997
1998 blk_mq_free_tag_set(&shost->tag_set);
1999 complete(&shost->tagset_freed);
2000}
2001
2002/**
2003 * scsi_device_from_queue - return sdev associated with a request_queue
2004 * @q: The request queue to return the sdev from
2005 *
2006 * Return the sdev associated with a request queue or NULL if the
2007 * request_queue does not reference a SCSI device.
2008 */
2009struct scsi_device *scsi_device_from_queue(struct request_queue *q)
2010{
2011 struct scsi_device *sdev = NULL;
2012
2013 if (q->mq_ops == &scsi_mq_ops_no_commit ||
2014 q->mq_ops == &scsi_mq_ops)
2015 sdev = q->queuedata;
2016 if (!sdev || !get_device(&sdev->sdev_gendev))
2017 sdev = NULL;
2018
2019 return sdev;
2020}
2021/*
2022 * pktcdvd should have been integrated into the SCSI layers, but for historical
2023 * reasons like the old IDE driver it isn't. This export allows it to safely
2024 * probe if a given device is a SCSI one and only attach to that.
2025 */
2026#ifdef CONFIG_CDROM_PKTCDVD_MODULE
2027EXPORT_SYMBOL_GPL(scsi_device_from_queue);
2028#endif
2029
2030/**
2031 * scsi_block_requests - Utility function used by low-level drivers to prevent
2032 * further commands from being queued to the device.
2033 * @shost: host in question
2034 *
2035 * There is no timer nor any other means by which the requests get unblocked
2036 * other than the low-level driver calling scsi_unblock_requests().
2037 */
2038void scsi_block_requests(struct Scsi_Host *shost)
2039{
2040 shost->host_self_blocked = 1;
2041}
2042EXPORT_SYMBOL(scsi_block_requests);
2043
2044/**
2045 * scsi_unblock_requests - Utility function used by low-level drivers to allow
2046 * further commands to be queued to the device.
2047 * @shost: host in question
2048 *
2049 * There is no timer nor any other means by which the requests get unblocked
2050 * other than the low-level driver calling scsi_unblock_requests(). This is done
2051 * as an API function so that changes to the internals of the scsi mid-layer
2052 * won't require wholesale changes to drivers that use this feature.
2053 */
2054void scsi_unblock_requests(struct Scsi_Host *shost)
2055{
2056 shost->host_self_blocked = 0;
2057 scsi_run_host_queues(shost);
2058}
2059EXPORT_SYMBOL(scsi_unblock_requests);
2060
2061void scsi_exit_queue(void)
2062{
2063 kmem_cache_destroy(scsi_sense_cache);
2064}
2065
2066/**
2067 * scsi_mode_select - issue a mode select
2068 * @sdev: SCSI device to be queried
2069 * @pf: Page format bit (1 == standard, 0 == vendor specific)
2070 * @sp: Save page bit (0 == don't save, 1 == save)
2071 * @buffer: request buffer (may not be smaller than eight bytes)
2072 * @len: length of request buffer.
2073 * @timeout: command timeout
2074 * @retries: number of retries before failing
2075 * @data: returns a structure abstracting the mode header data
2076 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2077 * must be SCSI_SENSE_BUFFERSIZE big.
2078 *
2079 * Returns zero if successful; negative error number or scsi
2080 * status on error
2081 *
2082 */
2083int scsi_mode_select(struct scsi_device *sdev, int pf, int sp,
2084 unsigned char *buffer, int len, int timeout, int retries,
2085 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2086{
2087 unsigned char cmd[10];
2088 unsigned char *real_buffer;
2089 int ret;
2090
2091 memset(cmd, 0, sizeof(cmd));
2092 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
2093
2094 /*
2095 * Use MODE SELECT(10) if the device asked for it or if the mode page
2096 * and the mode select header cannot fit within the maximumm 255 bytes
2097 * of the MODE SELECT(6) command.
2098 */
2099 if (sdev->use_10_for_ms ||
2100 len + 4 > 255 ||
2101 data->block_descriptor_length > 255) {
2102 if (len > 65535 - 8)
2103 return -EINVAL;
2104 real_buffer = kmalloc(8 + len, GFP_KERNEL);
2105 if (!real_buffer)
2106 return -ENOMEM;
2107 memcpy(real_buffer + 8, buffer, len);
2108 len += 8;
2109 real_buffer[0] = 0;
2110 real_buffer[1] = 0;
2111 real_buffer[2] = data->medium_type;
2112 real_buffer[3] = data->device_specific;
2113 real_buffer[4] = data->longlba ? 0x01 : 0;
2114 real_buffer[5] = 0;
2115 put_unaligned_be16(data->block_descriptor_length,
2116 &real_buffer[6]);
2117
2118 cmd[0] = MODE_SELECT_10;
2119 put_unaligned_be16(len, &cmd[7]);
2120 } else {
2121 if (data->longlba)
2122 return -EINVAL;
2123
2124 real_buffer = kmalloc(4 + len, GFP_KERNEL);
2125 if (!real_buffer)
2126 return -ENOMEM;
2127 memcpy(real_buffer + 4, buffer, len);
2128 len += 4;
2129 real_buffer[0] = 0;
2130 real_buffer[1] = data->medium_type;
2131 real_buffer[2] = data->device_specific;
2132 real_buffer[3] = data->block_descriptor_length;
2133
2134 cmd[0] = MODE_SELECT;
2135 cmd[4] = len;
2136 }
2137
2138 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
2139 sshdr, timeout, retries, NULL);
2140 kfree(real_buffer);
2141 return ret;
2142}
2143EXPORT_SYMBOL_GPL(scsi_mode_select);
2144
2145/**
2146 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
2147 * @sdev: SCSI device to be queried
2148 * @dbd: set to prevent mode sense from returning block descriptors
2149 * @modepage: mode page being requested
2150 * @buffer: request buffer (may not be smaller than eight bytes)
2151 * @len: length of request buffer.
2152 * @timeout: command timeout
2153 * @retries: number of retries before failing
2154 * @data: returns a structure abstracting the mode header data
2155 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2156 * must be SCSI_SENSE_BUFFERSIZE big.
2157 *
2158 * Returns zero if successful, or a negative error number on failure
2159 */
2160int
2161scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
2162 unsigned char *buffer, int len, int timeout, int retries,
2163 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2164{
2165 unsigned char cmd[12];
2166 int use_10_for_ms;
2167 int header_length;
2168 int result, retry_count = retries;
2169 struct scsi_sense_hdr my_sshdr;
2170
2171 memset(data, 0, sizeof(*data));
2172 memset(&cmd[0], 0, 12);
2173
2174 dbd = sdev->set_dbd_for_ms ? 8 : dbd;
2175 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
2176 cmd[2] = modepage;
2177
2178 /* caller might not be interested in sense, but we need it */
2179 if (!sshdr)
2180 sshdr = &my_sshdr;
2181
2182 retry:
2183 use_10_for_ms = sdev->use_10_for_ms || len > 255;
2184
2185 if (use_10_for_ms) {
2186 if (len < 8 || len > 65535)
2187 return -EINVAL;
2188
2189 cmd[0] = MODE_SENSE_10;
2190 put_unaligned_be16(len, &cmd[7]);
2191 header_length = 8;
2192 } else {
2193 if (len < 4)
2194 return -EINVAL;
2195
2196 cmd[0] = MODE_SENSE;
2197 cmd[4] = len;
2198 header_length = 4;
2199 }
2200
2201 memset(buffer, 0, len);
2202
2203 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
2204 sshdr, timeout, retries, NULL);
2205 if (result < 0)
2206 return result;
2207
2208 /* This code looks awful: what it's doing is making sure an
2209 * ILLEGAL REQUEST sense return identifies the actual command
2210 * byte as the problem. MODE_SENSE commands can return
2211 * ILLEGAL REQUEST if the code page isn't supported */
2212
2213 if (!scsi_status_is_good(result)) {
2214 if (scsi_sense_valid(sshdr)) {
2215 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
2216 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
2217 /*
2218 * Invalid command operation code: retry using
2219 * MODE SENSE(6) if this was a MODE SENSE(10)
2220 * request, except if the request mode page is
2221 * too large for MODE SENSE single byte
2222 * allocation length field.
2223 */
2224 if (use_10_for_ms) {
2225 if (len > 255)
2226 return -EIO;
2227 sdev->use_10_for_ms = 0;
2228 goto retry;
2229 }
2230 }
2231 if (scsi_status_is_check_condition(result) &&
2232 sshdr->sense_key == UNIT_ATTENTION &&
2233 retry_count) {
2234 retry_count--;
2235 goto retry;
2236 }
2237 }
2238 return -EIO;
2239 }
2240 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
2241 (modepage == 6 || modepage == 8))) {
2242 /* Initio breakage? */
2243 header_length = 0;
2244 data->length = 13;
2245 data->medium_type = 0;
2246 data->device_specific = 0;
2247 data->longlba = 0;
2248 data->block_descriptor_length = 0;
2249 } else if (use_10_for_ms) {
2250 data->length = get_unaligned_be16(&buffer[0]) + 2;
2251 data->medium_type = buffer[2];
2252 data->device_specific = buffer[3];
2253 data->longlba = buffer[4] & 0x01;
2254 data->block_descriptor_length = get_unaligned_be16(&buffer[6]);
2255 } else {
2256 data->length = buffer[0] + 1;
2257 data->medium_type = buffer[1];
2258 data->device_specific = buffer[2];
2259 data->block_descriptor_length = buffer[3];
2260 }
2261 data->header_length = header_length;
2262
2263 return 0;
2264}
2265EXPORT_SYMBOL(scsi_mode_sense);
2266
2267/**
2268 * scsi_test_unit_ready - test if unit is ready
2269 * @sdev: scsi device to change the state of.
2270 * @timeout: command timeout
2271 * @retries: number of retries before failing
2272 * @sshdr: outpout pointer for decoded sense information.
2273 *
2274 * Returns zero if unsuccessful or an error if TUR failed. For
2275 * removable media, UNIT_ATTENTION sets ->changed flag.
2276 **/
2277int
2278scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2279 struct scsi_sense_hdr *sshdr)
2280{
2281 char cmd[] = {
2282 TEST_UNIT_READY, 0, 0, 0, 0, 0,
2283 };
2284 int result;
2285
2286 /* try to eat the UNIT_ATTENTION if there are enough retries */
2287 do {
2288 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
2289 timeout, 1, NULL);
2290 if (sdev->removable && scsi_sense_valid(sshdr) &&
2291 sshdr->sense_key == UNIT_ATTENTION)
2292 sdev->changed = 1;
2293 } while (scsi_sense_valid(sshdr) &&
2294 sshdr->sense_key == UNIT_ATTENTION && --retries);
2295
2296 return result;
2297}
2298EXPORT_SYMBOL(scsi_test_unit_ready);
2299
2300/**
2301 * scsi_device_set_state - Take the given device through the device state model.
2302 * @sdev: scsi device to change the state of.
2303 * @state: state to change to.
2304 *
2305 * Returns zero if successful or an error if the requested
2306 * transition is illegal.
2307 */
2308int
2309scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2310{
2311 enum scsi_device_state oldstate = sdev->sdev_state;
2312
2313 if (state == oldstate)
2314 return 0;
2315
2316 switch (state) {
2317 case SDEV_CREATED:
2318 switch (oldstate) {
2319 case SDEV_CREATED_BLOCK:
2320 break;
2321 default:
2322 goto illegal;
2323 }
2324 break;
2325
2326 case SDEV_RUNNING:
2327 switch (oldstate) {
2328 case SDEV_CREATED:
2329 case SDEV_OFFLINE:
2330 case SDEV_TRANSPORT_OFFLINE:
2331 case SDEV_QUIESCE:
2332 case SDEV_BLOCK:
2333 break;
2334 default:
2335 goto illegal;
2336 }
2337 break;
2338
2339 case SDEV_QUIESCE:
2340 switch (oldstate) {
2341 case SDEV_RUNNING:
2342 case SDEV_OFFLINE:
2343 case SDEV_TRANSPORT_OFFLINE:
2344 break;
2345 default:
2346 goto illegal;
2347 }
2348 break;
2349
2350 case SDEV_OFFLINE:
2351 case SDEV_TRANSPORT_OFFLINE:
2352 switch (oldstate) {
2353 case SDEV_CREATED:
2354 case SDEV_RUNNING:
2355 case SDEV_QUIESCE:
2356 case SDEV_BLOCK:
2357 break;
2358 default:
2359 goto illegal;
2360 }
2361 break;
2362
2363 case SDEV_BLOCK:
2364 switch (oldstate) {
2365 case SDEV_RUNNING:
2366 case SDEV_CREATED_BLOCK:
2367 case SDEV_QUIESCE:
2368 case SDEV_OFFLINE:
2369 break;
2370 default:
2371 goto illegal;
2372 }
2373 break;
2374
2375 case SDEV_CREATED_BLOCK:
2376 switch (oldstate) {
2377 case SDEV_CREATED:
2378 break;
2379 default:
2380 goto illegal;
2381 }
2382 break;
2383
2384 case SDEV_CANCEL:
2385 switch (oldstate) {
2386 case SDEV_CREATED:
2387 case SDEV_RUNNING:
2388 case SDEV_QUIESCE:
2389 case SDEV_OFFLINE:
2390 case SDEV_TRANSPORT_OFFLINE:
2391 break;
2392 default:
2393 goto illegal;
2394 }
2395 break;
2396
2397 case SDEV_DEL:
2398 switch (oldstate) {
2399 case SDEV_CREATED:
2400 case SDEV_RUNNING:
2401 case SDEV_OFFLINE:
2402 case SDEV_TRANSPORT_OFFLINE:
2403 case SDEV_CANCEL:
2404 case SDEV_BLOCK:
2405 case SDEV_CREATED_BLOCK:
2406 break;
2407 default:
2408 goto illegal;
2409 }
2410 break;
2411
2412 }
2413 sdev->offline_already = false;
2414 sdev->sdev_state = state;
2415 return 0;
2416
2417 illegal:
2418 SCSI_LOG_ERROR_RECOVERY(1,
2419 sdev_printk(KERN_ERR, sdev,
2420 "Illegal state transition %s->%s",
2421 scsi_device_state_name(oldstate),
2422 scsi_device_state_name(state))
2423 );
2424 return -EINVAL;
2425}
2426EXPORT_SYMBOL(scsi_device_set_state);
2427
2428/**
2429 * scsi_evt_emit - emit a single SCSI device uevent
2430 * @sdev: associated SCSI device
2431 * @evt: event to emit
2432 *
2433 * Send a single uevent (scsi_event) to the associated scsi_device.
2434 */
2435static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2436{
2437 int idx = 0;
2438 char *envp[3];
2439
2440 switch (evt->evt_type) {
2441 case SDEV_EVT_MEDIA_CHANGE:
2442 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2443 break;
2444 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2445 scsi_rescan_device(&sdev->sdev_gendev);
2446 envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2447 break;
2448 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2449 envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2450 break;
2451 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2452 envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2453 break;
2454 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2455 envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2456 break;
2457 case SDEV_EVT_LUN_CHANGE_REPORTED:
2458 envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2459 break;
2460 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2461 envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
2462 break;
2463 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2464 envp[idx++] = "SDEV_UA=POWER_ON_RESET_OCCURRED";
2465 break;
2466 default:
2467 /* do nothing */
2468 break;
2469 }
2470
2471 envp[idx++] = NULL;
2472
2473 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2474}
2475
2476/**
2477 * scsi_evt_thread - send a uevent for each scsi event
2478 * @work: work struct for scsi_device
2479 *
2480 * Dispatch queued events to their associated scsi_device kobjects
2481 * as uevents.
2482 */
2483void scsi_evt_thread(struct work_struct *work)
2484{
2485 struct scsi_device *sdev;
2486 enum scsi_device_event evt_type;
2487 LIST_HEAD(event_list);
2488
2489 sdev = container_of(work, struct scsi_device, event_work);
2490
2491 for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
2492 if (test_and_clear_bit(evt_type, sdev->pending_events))
2493 sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
2494
2495 while (1) {
2496 struct scsi_event *evt;
2497 struct list_head *this, *tmp;
2498 unsigned long flags;
2499
2500 spin_lock_irqsave(&sdev->list_lock, flags);
2501 list_splice_init(&sdev->event_list, &event_list);
2502 spin_unlock_irqrestore(&sdev->list_lock, flags);
2503
2504 if (list_empty(&event_list))
2505 break;
2506
2507 list_for_each_safe(this, tmp, &event_list) {
2508 evt = list_entry(this, struct scsi_event, node);
2509 list_del(&evt->node);
2510 scsi_evt_emit(sdev, evt);
2511 kfree(evt);
2512 }
2513 }
2514}
2515
2516/**
2517 * sdev_evt_send - send asserted event to uevent thread
2518 * @sdev: scsi_device event occurred on
2519 * @evt: event to send
2520 *
2521 * Assert scsi device event asynchronously.
2522 */
2523void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2524{
2525 unsigned long flags;
2526
2527#if 0
2528 /* FIXME: currently this check eliminates all media change events
2529 * for polled devices. Need to update to discriminate between AN
2530 * and polled events */
2531 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2532 kfree(evt);
2533 return;
2534 }
2535#endif
2536
2537 spin_lock_irqsave(&sdev->list_lock, flags);
2538 list_add_tail(&evt->node, &sdev->event_list);
2539 schedule_work(&sdev->event_work);
2540 spin_unlock_irqrestore(&sdev->list_lock, flags);
2541}
2542EXPORT_SYMBOL_GPL(sdev_evt_send);
2543
2544/**
2545 * sdev_evt_alloc - allocate a new scsi event
2546 * @evt_type: type of event to allocate
2547 * @gfpflags: GFP flags for allocation
2548 *
2549 * Allocates and returns a new scsi_event.
2550 */
2551struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2552 gfp_t gfpflags)
2553{
2554 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2555 if (!evt)
2556 return NULL;
2557
2558 evt->evt_type = evt_type;
2559 INIT_LIST_HEAD(&evt->node);
2560
2561 /* evt_type-specific initialization, if any */
2562 switch (evt_type) {
2563 case SDEV_EVT_MEDIA_CHANGE:
2564 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2565 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2566 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2567 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2568 case SDEV_EVT_LUN_CHANGE_REPORTED:
2569 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2570 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2571 default:
2572 /* do nothing */
2573 break;
2574 }
2575
2576 return evt;
2577}
2578EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2579
2580/**
2581 * sdev_evt_send_simple - send asserted event to uevent thread
2582 * @sdev: scsi_device event occurred on
2583 * @evt_type: type of event to send
2584 * @gfpflags: GFP flags for allocation
2585 *
2586 * Assert scsi device event asynchronously, given an event type.
2587 */
2588void sdev_evt_send_simple(struct scsi_device *sdev,
2589 enum scsi_device_event evt_type, gfp_t gfpflags)
2590{
2591 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2592 if (!evt) {
2593 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2594 evt_type);
2595 return;
2596 }
2597
2598 sdev_evt_send(sdev, evt);
2599}
2600EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2601
2602/**
2603 * scsi_device_quiesce - Block all commands except power management.
2604 * @sdev: scsi device to quiesce.
2605 *
2606 * This works by trying to transition to the SDEV_QUIESCE state
2607 * (which must be a legal transition). When the device is in this
2608 * state, only power management requests will be accepted, all others will
2609 * be deferred.
2610 *
2611 * Must be called with user context, may sleep.
2612 *
2613 * Returns zero if unsuccessful or an error if not.
2614 */
2615int
2616scsi_device_quiesce(struct scsi_device *sdev)
2617{
2618 struct request_queue *q = sdev->request_queue;
2619 int err;
2620
2621 /*
2622 * It is allowed to call scsi_device_quiesce() multiple times from
2623 * the same context but concurrent scsi_device_quiesce() calls are
2624 * not allowed.
2625 */
2626 WARN_ON_ONCE(sdev->quiesced_by && sdev->quiesced_by != current);
2627
2628 if (sdev->quiesced_by == current)
2629 return 0;
2630
2631 blk_set_pm_only(q);
2632
2633 blk_mq_freeze_queue(q);
2634 /*
2635 * Ensure that the effect of blk_set_pm_only() will be visible
2636 * for percpu_ref_tryget() callers that occur after the queue
2637 * unfreeze even if the queue was already frozen before this function
2638 * was called. See also https://lwn.net/Articles/573497/.
2639 */
2640 synchronize_rcu();
2641 blk_mq_unfreeze_queue(q);
2642
2643 mutex_lock(&sdev->state_mutex);
2644 err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2645 if (err == 0)
2646 sdev->quiesced_by = current;
2647 else
2648 blk_clear_pm_only(q);
2649 mutex_unlock(&sdev->state_mutex);
2650
2651 return err;
2652}
2653EXPORT_SYMBOL(scsi_device_quiesce);
2654
2655/**
2656 * scsi_device_resume - Restart user issued commands to a quiesced device.
2657 * @sdev: scsi device to resume.
2658 *
2659 * Moves the device from quiesced back to running and restarts the
2660 * queues.
2661 *
2662 * Must be called with user context, may sleep.
2663 */
2664void scsi_device_resume(struct scsi_device *sdev)
2665{
2666 /* check if the device state was mutated prior to resume, and if
2667 * so assume the state is being managed elsewhere (for example
2668 * device deleted during suspend)
2669 */
2670 mutex_lock(&sdev->state_mutex);
2671 if (sdev->sdev_state == SDEV_QUIESCE)
2672 scsi_device_set_state(sdev, SDEV_RUNNING);
2673 if (sdev->quiesced_by) {
2674 sdev->quiesced_by = NULL;
2675 blk_clear_pm_only(sdev->request_queue);
2676 }
2677 mutex_unlock(&sdev->state_mutex);
2678}
2679EXPORT_SYMBOL(scsi_device_resume);
2680
2681static void
2682device_quiesce_fn(struct scsi_device *sdev, void *data)
2683{
2684 scsi_device_quiesce(sdev);
2685}
2686
2687void
2688scsi_target_quiesce(struct scsi_target *starget)
2689{
2690 starget_for_each_device(starget, NULL, device_quiesce_fn);
2691}
2692EXPORT_SYMBOL(scsi_target_quiesce);
2693
2694static void
2695device_resume_fn(struct scsi_device *sdev, void *data)
2696{
2697 scsi_device_resume(sdev);
2698}
2699
2700void
2701scsi_target_resume(struct scsi_target *starget)
2702{
2703 starget_for_each_device(starget, NULL, device_resume_fn);
2704}
2705EXPORT_SYMBOL(scsi_target_resume);
2706
2707static int __scsi_internal_device_block_nowait(struct scsi_device *sdev)
2708{
2709 if (scsi_device_set_state(sdev, SDEV_BLOCK))
2710 return scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2711
2712 return 0;
2713}
2714
2715void scsi_start_queue(struct scsi_device *sdev)
2716{
2717 if (cmpxchg(&sdev->queue_stopped, 1, 0))
2718 blk_mq_unquiesce_queue(sdev->request_queue);
2719}
2720
2721static void scsi_stop_queue(struct scsi_device *sdev, bool nowait)
2722{
2723 /*
2724 * The atomic variable of ->queue_stopped covers that
2725 * blk_mq_quiesce_queue* is balanced with blk_mq_unquiesce_queue.
2726 *
2727 * However, we still need to wait until quiesce is done
2728 * in case that queue has been stopped.
2729 */
2730 if (!cmpxchg(&sdev->queue_stopped, 0, 1)) {
2731 if (nowait)
2732 blk_mq_quiesce_queue_nowait(sdev->request_queue);
2733 else
2734 blk_mq_quiesce_queue(sdev->request_queue);
2735 } else {
2736 if (!nowait)
2737 blk_mq_wait_quiesce_done(sdev->request_queue->tag_set);
2738 }
2739}
2740
2741/**
2742 * scsi_internal_device_block_nowait - try to transition to the SDEV_BLOCK state
2743 * @sdev: device to block
2744 *
2745 * Pause SCSI command processing on the specified device. Does not sleep.
2746 *
2747 * Returns zero if successful or a negative error code upon failure.
2748 *
2749 * Notes:
2750 * This routine transitions the device to the SDEV_BLOCK state (which must be
2751 * a legal transition). When the device is in this state, command processing
2752 * is paused until the device leaves the SDEV_BLOCK state. See also
2753 * scsi_internal_device_unblock_nowait().
2754 */
2755int scsi_internal_device_block_nowait(struct scsi_device *sdev)
2756{
2757 int ret = __scsi_internal_device_block_nowait(sdev);
2758
2759 /*
2760 * The device has transitioned to SDEV_BLOCK. Stop the
2761 * block layer from calling the midlayer with this device's
2762 * request queue.
2763 */
2764 if (!ret)
2765 scsi_stop_queue(sdev, true);
2766 return ret;
2767}
2768EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait);
2769
2770/**
2771 * scsi_internal_device_block - try to transition to the SDEV_BLOCK state
2772 * @sdev: device to block
2773 *
2774 * Pause SCSI command processing on the specified device and wait until all
2775 * ongoing scsi_request_fn() / scsi_queue_rq() calls have finished. May sleep.
2776 *
2777 * Returns zero if successful or a negative error code upon failure.
2778 *
2779 * Note:
2780 * This routine transitions the device to the SDEV_BLOCK state (which must be
2781 * a legal transition). When the device is in this state, command processing
2782 * is paused until the device leaves the SDEV_BLOCK state. See also
2783 * scsi_internal_device_unblock().
2784 */
2785static int scsi_internal_device_block(struct scsi_device *sdev)
2786{
2787 int err;
2788
2789 mutex_lock(&sdev->state_mutex);
2790 err = __scsi_internal_device_block_nowait(sdev);
2791 if (err == 0)
2792 scsi_stop_queue(sdev, false);
2793 mutex_unlock(&sdev->state_mutex);
2794
2795 return err;
2796}
2797
2798/**
2799 * scsi_internal_device_unblock_nowait - resume a device after a block request
2800 * @sdev: device to resume
2801 * @new_state: state to set the device to after unblocking
2802 *
2803 * Restart the device queue for a previously suspended SCSI device. Does not
2804 * sleep.
2805 *
2806 * Returns zero if successful or a negative error code upon failure.
2807 *
2808 * Notes:
2809 * This routine transitions the device to the SDEV_RUNNING state or to one of
2810 * the offline states (which must be a legal transition) allowing the midlayer
2811 * to goose the queue for this device.
2812 */
2813int scsi_internal_device_unblock_nowait(struct scsi_device *sdev,
2814 enum scsi_device_state new_state)
2815{
2816 switch (new_state) {
2817 case SDEV_RUNNING:
2818 case SDEV_TRANSPORT_OFFLINE:
2819 break;
2820 default:
2821 return -EINVAL;
2822 }
2823
2824 /*
2825 * Try to transition the scsi device to SDEV_RUNNING or one of the
2826 * offlined states and goose the device queue if successful.
2827 */
2828 switch (sdev->sdev_state) {
2829 case SDEV_BLOCK:
2830 case SDEV_TRANSPORT_OFFLINE:
2831 sdev->sdev_state = new_state;
2832 break;
2833 case SDEV_CREATED_BLOCK:
2834 if (new_state == SDEV_TRANSPORT_OFFLINE ||
2835 new_state == SDEV_OFFLINE)
2836 sdev->sdev_state = new_state;
2837 else
2838 sdev->sdev_state = SDEV_CREATED;
2839 break;
2840 case SDEV_CANCEL:
2841 case SDEV_OFFLINE:
2842 break;
2843 default:
2844 return -EINVAL;
2845 }
2846 scsi_start_queue(sdev);
2847
2848 return 0;
2849}
2850EXPORT_SYMBOL_GPL(scsi_internal_device_unblock_nowait);
2851
2852/**
2853 * scsi_internal_device_unblock - resume a device after a block request
2854 * @sdev: device to resume
2855 * @new_state: state to set the device to after unblocking
2856 *
2857 * Restart the device queue for a previously suspended SCSI device. May sleep.
2858 *
2859 * Returns zero if successful or a negative error code upon failure.
2860 *
2861 * Notes:
2862 * This routine transitions the device to the SDEV_RUNNING state or to one of
2863 * the offline states (which must be a legal transition) allowing the midlayer
2864 * to goose the queue for this device.
2865 */
2866static int scsi_internal_device_unblock(struct scsi_device *sdev,
2867 enum scsi_device_state new_state)
2868{
2869 int ret;
2870
2871 mutex_lock(&sdev->state_mutex);
2872 ret = scsi_internal_device_unblock_nowait(sdev, new_state);
2873 mutex_unlock(&sdev->state_mutex);
2874
2875 return ret;
2876}
2877
2878static void
2879device_block(struct scsi_device *sdev, void *data)
2880{
2881 int ret;
2882
2883 ret = scsi_internal_device_block(sdev);
2884
2885 WARN_ONCE(ret, "scsi_internal_device_block(%s) failed: ret = %d\n",
2886 dev_name(&sdev->sdev_gendev), ret);
2887}
2888
2889static int
2890target_block(struct device *dev, void *data)
2891{
2892 if (scsi_is_target_device(dev))
2893 starget_for_each_device(to_scsi_target(dev), NULL,
2894 device_block);
2895 return 0;
2896}
2897
2898void
2899scsi_target_block(struct device *dev)
2900{
2901 if (scsi_is_target_device(dev))
2902 starget_for_each_device(to_scsi_target(dev), NULL,
2903 device_block);
2904 else
2905 device_for_each_child(dev, NULL, target_block);
2906}
2907EXPORT_SYMBOL_GPL(scsi_target_block);
2908
2909static void
2910device_unblock(struct scsi_device *sdev, void *data)
2911{
2912 scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
2913}
2914
2915static int
2916target_unblock(struct device *dev, void *data)
2917{
2918 if (scsi_is_target_device(dev))
2919 starget_for_each_device(to_scsi_target(dev), data,
2920 device_unblock);
2921 return 0;
2922}
2923
2924void
2925scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
2926{
2927 if (scsi_is_target_device(dev))
2928 starget_for_each_device(to_scsi_target(dev), &new_state,
2929 device_unblock);
2930 else
2931 device_for_each_child(dev, &new_state, target_unblock);
2932}
2933EXPORT_SYMBOL_GPL(scsi_target_unblock);
2934
2935int
2936scsi_host_block(struct Scsi_Host *shost)
2937{
2938 struct scsi_device *sdev;
2939 int ret = 0;
2940
2941 /*
2942 * Call scsi_internal_device_block_nowait so we can avoid
2943 * calling synchronize_rcu() for each LUN.
2944 */
2945 shost_for_each_device(sdev, shost) {
2946 mutex_lock(&sdev->state_mutex);
2947 ret = scsi_internal_device_block_nowait(sdev);
2948 mutex_unlock(&sdev->state_mutex);
2949 if (ret) {
2950 scsi_device_put(sdev);
2951 break;
2952 }
2953 }
2954
2955 /*
2956 * SCSI never enables blk-mq's BLK_MQ_F_BLOCKING flag so
2957 * calling synchronize_rcu() once is enough.
2958 */
2959 WARN_ON_ONCE(shost->tag_set.flags & BLK_MQ_F_BLOCKING);
2960
2961 if (!ret)
2962 synchronize_rcu();
2963
2964 return ret;
2965}
2966EXPORT_SYMBOL_GPL(scsi_host_block);
2967
2968int
2969scsi_host_unblock(struct Scsi_Host *shost, int new_state)
2970{
2971 struct scsi_device *sdev;
2972 int ret = 0;
2973
2974 shost_for_each_device(sdev, shost) {
2975 ret = scsi_internal_device_unblock(sdev, new_state);
2976 if (ret) {
2977 scsi_device_put(sdev);
2978 break;
2979 }
2980 }
2981 return ret;
2982}
2983EXPORT_SYMBOL_GPL(scsi_host_unblock);
2984
2985/**
2986 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
2987 * @sgl: scatter-gather list
2988 * @sg_count: number of segments in sg
2989 * @offset: offset in bytes into sg, on return offset into the mapped area
2990 * @len: bytes to map, on return number of bytes mapped
2991 *
2992 * Returns virtual address of the start of the mapped page
2993 */
2994void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
2995 size_t *offset, size_t *len)
2996{
2997 int i;
2998 size_t sg_len = 0, len_complete = 0;
2999 struct scatterlist *sg;
3000 struct page *page;
3001
3002 WARN_ON(!irqs_disabled());
3003
3004 for_each_sg(sgl, sg, sg_count, i) {
3005 len_complete = sg_len; /* Complete sg-entries */
3006 sg_len += sg->length;
3007 if (sg_len > *offset)
3008 break;
3009 }
3010
3011 if (unlikely(i == sg_count)) {
3012 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
3013 "elements %d\n",
3014 __func__, sg_len, *offset, sg_count);
3015 WARN_ON(1);
3016 return NULL;
3017 }
3018
3019 /* Offset starting from the beginning of first page in this sg-entry */
3020 *offset = *offset - len_complete + sg->offset;
3021
3022 /* Assumption: contiguous pages can be accessed as "page + i" */
3023 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
3024 *offset &= ~PAGE_MASK;
3025
3026 /* Bytes in this sg-entry from *offset to the end of the page */
3027 sg_len = PAGE_SIZE - *offset;
3028 if (*len > sg_len)
3029 *len = sg_len;
3030
3031 return kmap_atomic(page);
3032}
3033EXPORT_SYMBOL(scsi_kmap_atomic_sg);
3034
3035/**
3036 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
3037 * @virt: virtual address to be unmapped
3038 */
3039void scsi_kunmap_atomic_sg(void *virt)
3040{
3041 kunmap_atomic(virt);
3042}
3043EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
3044
3045void sdev_disable_disk_events(struct scsi_device *sdev)
3046{
3047 atomic_inc(&sdev->disk_events_disable_depth);
3048}
3049EXPORT_SYMBOL(sdev_disable_disk_events);
3050
3051void sdev_enable_disk_events(struct scsi_device *sdev)
3052{
3053 if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0))
3054 return;
3055 atomic_dec(&sdev->disk_events_disable_depth);
3056}
3057EXPORT_SYMBOL(sdev_enable_disk_events);
3058
3059static unsigned char designator_prio(const unsigned char *d)
3060{
3061 if (d[1] & 0x30)
3062 /* not associated with LUN */
3063 return 0;
3064
3065 if (d[3] == 0)
3066 /* invalid length */
3067 return 0;
3068
3069 /*
3070 * Order of preference for lun descriptor:
3071 * - SCSI name string
3072 * - NAA IEEE Registered Extended
3073 * - EUI-64 based 16-byte
3074 * - EUI-64 based 12-byte
3075 * - NAA IEEE Registered
3076 * - NAA IEEE Extended
3077 * - EUI-64 based 8-byte
3078 * - SCSI name string (truncated)
3079 * - T10 Vendor ID
3080 * as longer descriptors reduce the likelyhood
3081 * of identification clashes.
3082 */
3083
3084 switch (d[1] & 0xf) {
3085 case 8:
3086 /* SCSI name string, variable-length UTF-8 */
3087 return 9;
3088 case 3:
3089 switch (d[4] >> 4) {
3090 case 6:
3091 /* NAA registered extended */
3092 return 8;
3093 case 5:
3094 /* NAA registered */
3095 return 5;
3096 case 4:
3097 /* NAA extended */
3098 return 4;
3099 case 3:
3100 /* NAA locally assigned */
3101 return 1;
3102 default:
3103 break;
3104 }
3105 break;
3106 case 2:
3107 switch (d[3]) {
3108 case 16:
3109 /* EUI64-based, 16 byte */
3110 return 7;
3111 case 12:
3112 /* EUI64-based, 12 byte */
3113 return 6;
3114 case 8:
3115 /* EUI64-based, 8 byte */
3116 return 3;
3117 default:
3118 break;
3119 }
3120 break;
3121 case 1:
3122 /* T10 vendor ID */
3123 return 1;
3124 default:
3125 break;
3126 }
3127
3128 return 0;
3129}
3130
3131/**
3132 * scsi_vpd_lun_id - return a unique device identification
3133 * @sdev: SCSI device
3134 * @id: buffer for the identification
3135 * @id_len: length of the buffer
3136 *
3137 * Copies a unique device identification into @id based
3138 * on the information in the VPD page 0x83 of the device.
3139 * The string will be formatted as a SCSI name string.
3140 *
3141 * Returns the length of the identification or error on failure.
3142 * If the identifier is longer than the supplied buffer the actual
3143 * identifier length is returned and the buffer is not zero-padded.
3144 */
3145int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len)
3146{
3147 u8 cur_id_prio = 0;
3148 u8 cur_id_size = 0;
3149 const unsigned char *d, *cur_id_str;
3150 const struct scsi_vpd *vpd_pg83;
3151 int id_size = -EINVAL;
3152
3153 rcu_read_lock();
3154 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3155 if (!vpd_pg83) {
3156 rcu_read_unlock();
3157 return -ENXIO;
3158 }
3159
3160 /* The id string must be at least 20 bytes + terminating NULL byte */
3161 if (id_len < 21) {
3162 rcu_read_unlock();
3163 return -EINVAL;
3164 }
3165
3166 memset(id, 0, id_len);
3167 for (d = vpd_pg83->data + 4;
3168 d < vpd_pg83->data + vpd_pg83->len;
3169 d += d[3] + 4) {
3170 u8 prio = designator_prio(d);
3171
3172 if (prio == 0 || cur_id_prio > prio)
3173 continue;
3174
3175 switch (d[1] & 0xf) {
3176 case 0x1:
3177 /* T10 Vendor ID */
3178 if (cur_id_size > d[3])
3179 break;
3180 cur_id_prio = prio;
3181 cur_id_size = d[3];
3182 if (cur_id_size + 4 > id_len)
3183 cur_id_size = id_len - 4;
3184 cur_id_str = d + 4;
3185 id_size = snprintf(id, id_len, "t10.%*pE",
3186 cur_id_size, cur_id_str);
3187 break;
3188 case 0x2:
3189 /* EUI-64 */
3190 cur_id_prio = prio;
3191 cur_id_size = d[3];
3192 cur_id_str = d + 4;
3193 switch (cur_id_size) {
3194 case 8:
3195 id_size = snprintf(id, id_len,
3196 "eui.%8phN",
3197 cur_id_str);
3198 break;
3199 case 12:
3200 id_size = snprintf(id, id_len,
3201 "eui.%12phN",
3202 cur_id_str);
3203 break;
3204 case 16:
3205 id_size = snprintf(id, id_len,
3206 "eui.%16phN",
3207 cur_id_str);
3208 break;
3209 default:
3210 break;
3211 }
3212 break;
3213 case 0x3:
3214 /* NAA */
3215 cur_id_prio = prio;
3216 cur_id_size = d[3];
3217 cur_id_str = d + 4;
3218 switch (cur_id_size) {
3219 case 8:
3220 id_size = snprintf(id, id_len,
3221 "naa.%8phN",
3222 cur_id_str);
3223 break;
3224 case 16:
3225 id_size = snprintf(id, id_len,
3226 "naa.%16phN",
3227 cur_id_str);
3228 break;
3229 default:
3230 break;
3231 }
3232 break;
3233 case 0x8:
3234 /* SCSI name string */
3235 if (cur_id_size > d[3])
3236 break;
3237 /* Prefer others for truncated descriptor */
3238 if (d[3] > id_len) {
3239 prio = 2;
3240 if (cur_id_prio > prio)
3241 break;
3242 }
3243 cur_id_prio = prio;
3244 cur_id_size = id_size = d[3];
3245 cur_id_str = d + 4;
3246 if (cur_id_size >= id_len)
3247 cur_id_size = id_len - 1;
3248 memcpy(id, cur_id_str, cur_id_size);
3249 break;
3250 default:
3251 break;
3252 }
3253 }
3254 rcu_read_unlock();
3255
3256 return id_size;
3257}
3258EXPORT_SYMBOL(scsi_vpd_lun_id);
3259
3260/*
3261 * scsi_vpd_tpg_id - return a target port group identifier
3262 * @sdev: SCSI device
3263 *
3264 * Returns the Target Port Group identifier from the information
3265 * froom VPD page 0x83 of the device.
3266 *
3267 * Returns the identifier or error on failure.
3268 */
3269int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id)
3270{
3271 const unsigned char *d;
3272 const struct scsi_vpd *vpd_pg83;
3273 int group_id = -EAGAIN, rel_port = -1;
3274
3275 rcu_read_lock();
3276 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3277 if (!vpd_pg83) {
3278 rcu_read_unlock();
3279 return -ENXIO;
3280 }
3281
3282 d = vpd_pg83->data + 4;
3283 while (d < vpd_pg83->data + vpd_pg83->len) {
3284 switch (d[1] & 0xf) {
3285 case 0x4:
3286 /* Relative target port */
3287 rel_port = get_unaligned_be16(&d[6]);
3288 break;
3289 case 0x5:
3290 /* Target port group */
3291 group_id = get_unaligned_be16(&d[6]);
3292 break;
3293 default:
3294 break;
3295 }
3296 d += d[3] + 4;
3297 }
3298 rcu_read_unlock();
3299
3300 if (group_id >= 0 && rel_id && rel_port != -1)
3301 *rel_id = rel_port;
3302
3303 return group_id;
3304}
3305EXPORT_SYMBOL(scsi_vpd_tpg_id);
3306
3307/**
3308 * scsi_build_sense - build sense data for a command
3309 * @scmd: scsi command for which the sense should be formatted
3310 * @desc: Sense format (non-zero == descriptor format,
3311 * 0 == fixed format)
3312 * @key: Sense key
3313 * @asc: Additional sense code
3314 * @ascq: Additional sense code qualifier
3315 *
3316 **/
3317void scsi_build_sense(struct scsi_cmnd *scmd, int desc, u8 key, u8 asc, u8 ascq)
3318{
3319 scsi_build_sense_buffer(desc, scmd->sense_buffer, key, asc, ascq);
3320 scmd->result = SAM_STAT_CHECK_CONDITION;
3321}
3322EXPORT_SYMBOL_GPL(scsi_build_sense);
1/*
2 * scsi_lib.c Copyright (C) 1999 Eric Youngdale
3 *
4 * SCSI queueing library.
5 * Initial versions: Eric Youngdale (eric@andante.org).
6 * Based upon conversations with large numbers
7 * of people at Linux Expo.
8 */
9
10#include <linux/bio.h>
11#include <linux/bitops.h>
12#include <linux/blkdev.h>
13#include <linux/completion.h>
14#include <linux/kernel.h>
15#include <linux/export.h>
16#include <linux/mempool.h>
17#include <linux/slab.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
24#include <scsi/scsi.h>
25#include <scsi/scsi_cmnd.h>
26#include <scsi/scsi_dbg.h>
27#include <scsi/scsi_device.h>
28#include <scsi/scsi_driver.h>
29#include <scsi/scsi_eh.h>
30#include <scsi/scsi_host.h>
31
32#include "scsi_priv.h"
33#include "scsi_logging.h"
34
35
36#define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools)
37#define SG_MEMPOOL_SIZE 2
38
39struct scsi_host_sg_pool {
40 size_t size;
41 char *name;
42 struct kmem_cache *slab;
43 mempool_t *pool;
44};
45
46#define SP(x) { x, "sgpool-" __stringify(x) }
47#if (SCSI_MAX_SG_SEGMENTS < 32)
48#error SCSI_MAX_SG_SEGMENTS is too small (must be 32 or greater)
49#endif
50static struct scsi_host_sg_pool scsi_sg_pools[] = {
51 SP(8),
52 SP(16),
53#if (SCSI_MAX_SG_SEGMENTS > 32)
54 SP(32),
55#if (SCSI_MAX_SG_SEGMENTS > 64)
56 SP(64),
57#if (SCSI_MAX_SG_SEGMENTS > 128)
58 SP(128),
59#if (SCSI_MAX_SG_SEGMENTS > 256)
60#error SCSI_MAX_SG_SEGMENTS is too large (256 MAX)
61#endif
62#endif
63#endif
64#endif
65 SP(SCSI_MAX_SG_SEGMENTS)
66};
67#undef SP
68
69struct kmem_cache *scsi_sdb_cache;
70
71/*
72 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
73 * not change behaviour from the previous unplug mechanism, experimentation
74 * may prove this needs changing.
75 */
76#define SCSI_QUEUE_DELAY 3
77
78/**
79 * __scsi_queue_insert - private queue insertion
80 * @cmd: The SCSI command being requeued
81 * @reason: The reason for the requeue
82 * @unbusy: Whether the queue should be unbusied
83 *
84 * This is a private queue insertion. The public interface
85 * scsi_queue_insert() always assumes the queue should be unbusied
86 * because it's always called before the completion. This function is
87 * for a requeue after completion, which should only occur in this
88 * file.
89 */
90static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy)
91{
92 struct Scsi_Host *host = cmd->device->host;
93 struct scsi_device *device = cmd->device;
94 struct scsi_target *starget = scsi_target(device);
95 struct request_queue *q = device->request_queue;
96 unsigned long flags;
97
98 SCSI_LOG_MLQUEUE(1,
99 printk("Inserting command %p into mlqueue\n", cmd));
100
101 /*
102 * Set the appropriate busy bit for the device/host.
103 *
104 * If the host/device isn't busy, assume that something actually
105 * completed, and that we should be able to queue a command now.
106 *
107 * Note that the prior mid-layer assumption that any host could
108 * always queue at least one command is now broken. The mid-layer
109 * will implement a user specifiable stall (see
110 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
111 * if a command is requeued with no other commands outstanding
112 * either for the device or for the host.
113 */
114 switch (reason) {
115 case SCSI_MLQUEUE_HOST_BUSY:
116 host->host_blocked = host->max_host_blocked;
117 break;
118 case SCSI_MLQUEUE_DEVICE_BUSY:
119 case SCSI_MLQUEUE_EH_RETRY:
120 device->device_blocked = device->max_device_blocked;
121 break;
122 case SCSI_MLQUEUE_TARGET_BUSY:
123 starget->target_blocked = starget->max_target_blocked;
124 break;
125 }
126
127 /*
128 * Decrement the counters, since these commands are no longer
129 * active on the host/device.
130 */
131 if (unbusy)
132 scsi_device_unbusy(device);
133
134 /*
135 * Requeue this command. It will go before all other commands
136 * that are already in the queue. Schedule requeue work under
137 * lock such that the kblockd_schedule_work() call happens
138 * before blk_cleanup_queue() finishes.
139 */
140 cmd->result = 0;
141 spin_lock_irqsave(q->queue_lock, flags);
142 blk_requeue_request(q, cmd->request);
143 kblockd_schedule_work(q, &device->requeue_work);
144 spin_unlock_irqrestore(q->queue_lock, flags);
145}
146
147/*
148 * Function: scsi_queue_insert()
149 *
150 * Purpose: Insert a command in the midlevel queue.
151 *
152 * Arguments: cmd - command that we are adding to queue.
153 * reason - why we are inserting command to queue.
154 *
155 * Lock status: Assumed that lock is not held upon entry.
156 *
157 * Returns: Nothing.
158 *
159 * Notes: We do this for one of two cases. Either the host is busy
160 * and it cannot accept any more commands for the time being,
161 * or the device returned QUEUE_FULL and can accept no more
162 * commands.
163 * Notes: This could be called either from an interrupt context or a
164 * normal process context.
165 */
166void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
167{
168 __scsi_queue_insert(cmd, reason, 1);
169}
170/**
171 * scsi_execute - insert request and wait for the result
172 * @sdev: scsi device
173 * @cmd: scsi command
174 * @data_direction: data direction
175 * @buffer: data buffer
176 * @bufflen: len of buffer
177 * @sense: optional sense buffer
178 * @timeout: request timeout in seconds
179 * @retries: number of times to retry request
180 * @flags: or into request flags;
181 * @resid: optional residual length
182 *
183 * returns the req->errors value which is the scsi_cmnd result
184 * field.
185 */
186int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
187 int data_direction, void *buffer, unsigned bufflen,
188 unsigned char *sense, int timeout, int retries, u64 flags,
189 int *resid)
190{
191 struct request *req;
192 int write = (data_direction == DMA_TO_DEVICE);
193 int ret = DRIVER_ERROR << 24;
194
195 req = blk_get_request(sdev->request_queue, write, __GFP_WAIT);
196 if (!req)
197 return ret;
198
199 if (bufflen && blk_rq_map_kern(sdev->request_queue, req,
200 buffer, bufflen, __GFP_WAIT))
201 goto out;
202
203 req->cmd_len = COMMAND_SIZE(cmd[0]);
204 memcpy(req->cmd, cmd, req->cmd_len);
205 req->sense = sense;
206 req->sense_len = 0;
207 req->retries = retries;
208 req->timeout = timeout;
209 req->cmd_type = REQ_TYPE_BLOCK_PC;
210 req->cmd_flags |= flags | REQ_QUIET | REQ_PREEMPT;
211
212 /*
213 * head injection *required* here otherwise quiesce won't work
214 */
215 blk_execute_rq(req->q, NULL, req, 1);
216
217 /*
218 * Some devices (USB mass-storage in particular) may transfer
219 * garbage data together with a residue indicating that the data
220 * is invalid. Prevent the garbage from being misinterpreted
221 * and prevent security leaks by zeroing out the excess data.
222 */
223 if (unlikely(req->resid_len > 0 && req->resid_len <= bufflen))
224 memset(buffer + (bufflen - req->resid_len), 0, req->resid_len);
225
226 if (resid)
227 *resid = req->resid_len;
228 ret = req->errors;
229 out:
230 blk_put_request(req);
231
232 return ret;
233}
234EXPORT_SYMBOL(scsi_execute);
235
236int scsi_execute_req_flags(struct scsi_device *sdev, const unsigned char *cmd,
237 int data_direction, void *buffer, unsigned bufflen,
238 struct scsi_sense_hdr *sshdr, int timeout, int retries,
239 int *resid, u64 flags)
240{
241 char *sense = NULL;
242 int result;
243
244 if (sshdr) {
245 sense = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO);
246 if (!sense)
247 return DRIVER_ERROR << 24;
248 }
249 result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen,
250 sense, timeout, retries, flags, resid);
251 if (sshdr)
252 scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr);
253
254 kfree(sense);
255 return result;
256}
257EXPORT_SYMBOL(scsi_execute_req_flags);
258
259/*
260 * Function: scsi_init_cmd_errh()
261 *
262 * Purpose: Initialize cmd fields related to error handling.
263 *
264 * Arguments: cmd - command that is ready to be queued.
265 *
266 * Notes: This function has the job of initializing a number of
267 * fields related to error handling. Typically this will
268 * be called once for each command, as required.
269 */
270static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
271{
272 cmd->serial_number = 0;
273 scsi_set_resid(cmd, 0);
274 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
275 if (cmd->cmd_len == 0)
276 cmd->cmd_len = scsi_command_size(cmd->cmnd);
277}
278
279void scsi_device_unbusy(struct scsi_device *sdev)
280{
281 struct Scsi_Host *shost = sdev->host;
282 struct scsi_target *starget = scsi_target(sdev);
283 unsigned long flags;
284
285 spin_lock_irqsave(shost->host_lock, flags);
286 shost->host_busy--;
287 starget->target_busy--;
288 if (unlikely(scsi_host_in_recovery(shost) &&
289 (shost->host_failed || shost->host_eh_scheduled)))
290 scsi_eh_wakeup(shost);
291 spin_unlock(shost->host_lock);
292 spin_lock(sdev->request_queue->queue_lock);
293 sdev->device_busy--;
294 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
295}
296
297/*
298 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
299 * and call blk_run_queue for all the scsi_devices on the target -
300 * including current_sdev first.
301 *
302 * Called with *no* scsi locks held.
303 */
304static void scsi_single_lun_run(struct scsi_device *current_sdev)
305{
306 struct Scsi_Host *shost = current_sdev->host;
307 struct scsi_device *sdev, *tmp;
308 struct scsi_target *starget = scsi_target(current_sdev);
309 unsigned long flags;
310
311 spin_lock_irqsave(shost->host_lock, flags);
312 starget->starget_sdev_user = NULL;
313 spin_unlock_irqrestore(shost->host_lock, flags);
314
315 /*
316 * Call blk_run_queue for all LUNs on the target, starting with
317 * current_sdev. We race with others (to set starget_sdev_user),
318 * but in most cases, we will be first. Ideally, each LU on the
319 * target would get some limited time or requests on the target.
320 */
321 blk_run_queue(current_sdev->request_queue);
322
323 spin_lock_irqsave(shost->host_lock, flags);
324 if (starget->starget_sdev_user)
325 goto out;
326 list_for_each_entry_safe(sdev, tmp, &starget->devices,
327 same_target_siblings) {
328 if (sdev == current_sdev)
329 continue;
330 if (scsi_device_get(sdev))
331 continue;
332
333 spin_unlock_irqrestore(shost->host_lock, flags);
334 blk_run_queue(sdev->request_queue);
335 spin_lock_irqsave(shost->host_lock, flags);
336
337 scsi_device_put(sdev);
338 }
339 out:
340 spin_unlock_irqrestore(shost->host_lock, flags);
341}
342
343static inline int scsi_device_is_busy(struct scsi_device *sdev)
344{
345 if (sdev->device_busy >= sdev->queue_depth || sdev->device_blocked)
346 return 1;
347
348 return 0;
349}
350
351static inline int scsi_target_is_busy(struct scsi_target *starget)
352{
353 return ((starget->can_queue > 0 &&
354 starget->target_busy >= starget->can_queue) ||
355 starget->target_blocked);
356}
357
358static inline int scsi_host_is_busy(struct Scsi_Host *shost)
359{
360 if ((shost->can_queue > 0 && shost->host_busy >= shost->can_queue) ||
361 shost->host_blocked || shost->host_self_blocked)
362 return 1;
363
364 return 0;
365}
366
367static void scsi_starved_list_run(struct Scsi_Host *shost)
368{
369 LIST_HEAD(starved_list);
370 struct scsi_device *sdev;
371 unsigned long flags;
372
373 spin_lock_irqsave(shost->host_lock, flags);
374 list_splice_init(&shost->starved_list, &starved_list);
375
376 while (!list_empty(&starved_list)) {
377 struct request_queue *slq;
378
379 /*
380 * As long as shost is accepting commands and we have
381 * starved queues, call blk_run_queue. scsi_request_fn
382 * drops the queue_lock and can add us back to the
383 * starved_list.
384 *
385 * host_lock protects the starved_list and starved_entry.
386 * scsi_request_fn must get the host_lock before checking
387 * or modifying starved_list or starved_entry.
388 */
389 if (scsi_host_is_busy(shost))
390 break;
391
392 sdev = list_entry(starved_list.next,
393 struct scsi_device, starved_entry);
394 list_del_init(&sdev->starved_entry);
395 if (scsi_target_is_busy(scsi_target(sdev))) {
396 list_move_tail(&sdev->starved_entry,
397 &shost->starved_list);
398 continue;
399 }
400
401 /*
402 * Once we drop the host lock, a racing scsi_remove_device()
403 * call may remove the sdev from the starved list and destroy
404 * it and the queue. Mitigate by taking a reference to the
405 * queue and never touching the sdev again after we drop the
406 * host lock. Note: if __scsi_remove_device() invokes
407 * blk_cleanup_queue() before the queue is run from this
408 * function then blk_run_queue() will return immediately since
409 * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING.
410 */
411 slq = sdev->request_queue;
412 if (!blk_get_queue(slq))
413 continue;
414 spin_unlock_irqrestore(shost->host_lock, flags);
415
416 blk_run_queue(slq);
417 blk_put_queue(slq);
418
419 spin_lock_irqsave(shost->host_lock, flags);
420 }
421 /* put any unprocessed entries back */
422 list_splice(&starved_list, &shost->starved_list);
423 spin_unlock_irqrestore(shost->host_lock, flags);
424}
425
426/*
427 * Function: scsi_run_queue()
428 *
429 * Purpose: Select a proper request queue to serve next
430 *
431 * Arguments: q - last request's queue
432 *
433 * Returns: Nothing
434 *
435 * Notes: The previous command was completely finished, start
436 * a new one if possible.
437 */
438static void scsi_run_queue(struct request_queue *q)
439{
440 struct scsi_device *sdev = q->queuedata;
441
442 if (scsi_target(sdev)->single_lun)
443 scsi_single_lun_run(sdev);
444 if (!list_empty(&sdev->host->starved_list))
445 scsi_starved_list_run(sdev->host);
446
447 blk_run_queue(q);
448}
449
450void scsi_requeue_run_queue(struct work_struct *work)
451{
452 struct scsi_device *sdev;
453 struct request_queue *q;
454
455 sdev = container_of(work, struct scsi_device, requeue_work);
456 q = sdev->request_queue;
457 scsi_run_queue(q);
458}
459
460/*
461 * Function: scsi_requeue_command()
462 *
463 * Purpose: Handle post-processing of completed commands.
464 *
465 * Arguments: q - queue to operate on
466 * cmd - command that may need to be requeued.
467 *
468 * Returns: Nothing
469 *
470 * Notes: After command completion, there may be blocks left
471 * over which weren't finished by the previous command
472 * this can be for a number of reasons - the main one is
473 * I/O errors in the middle of the request, in which case
474 * we need to request the blocks that come after the bad
475 * sector.
476 * Notes: Upon return, cmd is a stale pointer.
477 */
478static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd)
479{
480 struct scsi_device *sdev = cmd->device;
481 struct request *req = cmd->request;
482 unsigned long flags;
483
484 spin_lock_irqsave(q->queue_lock, flags);
485 blk_unprep_request(req);
486 req->special = NULL;
487 scsi_put_command(cmd);
488 blk_requeue_request(q, req);
489 spin_unlock_irqrestore(q->queue_lock, flags);
490
491 scsi_run_queue(q);
492
493 put_device(&sdev->sdev_gendev);
494}
495
496void scsi_next_command(struct scsi_cmnd *cmd)
497{
498 struct scsi_device *sdev = cmd->device;
499 struct request_queue *q = sdev->request_queue;
500
501 scsi_put_command(cmd);
502 scsi_run_queue(q);
503
504 put_device(&sdev->sdev_gendev);
505}
506
507void scsi_run_host_queues(struct Scsi_Host *shost)
508{
509 struct scsi_device *sdev;
510
511 shost_for_each_device(sdev, shost)
512 scsi_run_queue(sdev->request_queue);
513}
514
515static void __scsi_release_buffers(struct scsi_cmnd *, int);
516
517/*
518 * Function: scsi_end_request()
519 *
520 * Purpose: Post-processing of completed commands (usually invoked at end
521 * of upper level post-processing and scsi_io_completion).
522 *
523 * Arguments: cmd - command that is complete.
524 * error - 0 if I/O indicates success, < 0 for I/O error.
525 * bytes - number of bytes of completed I/O
526 * requeue - indicates whether we should requeue leftovers.
527 *
528 * Lock status: Assumed that lock is not held upon entry.
529 *
530 * Returns: cmd if requeue required, NULL otherwise.
531 *
532 * Notes: This is called for block device requests in order to
533 * mark some number of sectors as complete.
534 *
535 * We are guaranteeing that the request queue will be goosed
536 * at some point during this call.
537 * Notes: If cmd was requeued, upon return it will be a stale pointer.
538 */
539static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int error,
540 int bytes, int requeue)
541{
542 struct request_queue *q = cmd->device->request_queue;
543 struct request *req = cmd->request;
544
545 /*
546 * If there are blocks left over at the end, set up the command
547 * to queue the remainder of them.
548 */
549 if (blk_end_request(req, error, bytes)) {
550 /* kill remainder if no retrys */
551 if (error && scsi_noretry_cmd(cmd))
552 blk_end_request_all(req, error);
553 else {
554 if (requeue) {
555 /*
556 * Bleah. Leftovers again. Stick the
557 * leftovers in the front of the
558 * queue, and goose the queue again.
559 */
560 scsi_release_buffers(cmd);
561 scsi_requeue_command(q, cmd);
562 cmd = NULL;
563 }
564 return cmd;
565 }
566 }
567
568 /*
569 * This will goose the queue request function at the end, so we don't
570 * need to worry about launching another command.
571 */
572 __scsi_release_buffers(cmd, 0);
573 scsi_next_command(cmd);
574 return NULL;
575}
576
577static inline unsigned int scsi_sgtable_index(unsigned short nents)
578{
579 unsigned int index;
580
581 BUG_ON(nents > SCSI_MAX_SG_SEGMENTS);
582
583 if (nents <= 8)
584 index = 0;
585 else
586 index = get_count_order(nents) - 3;
587
588 return index;
589}
590
591static void scsi_sg_free(struct scatterlist *sgl, unsigned int nents)
592{
593 struct scsi_host_sg_pool *sgp;
594
595 sgp = scsi_sg_pools + scsi_sgtable_index(nents);
596 mempool_free(sgl, sgp->pool);
597}
598
599static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask)
600{
601 struct scsi_host_sg_pool *sgp;
602
603 sgp = scsi_sg_pools + scsi_sgtable_index(nents);
604 return mempool_alloc(sgp->pool, gfp_mask);
605}
606
607static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents,
608 gfp_t gfp_mask)
609{
610 int ret;
611
612 BUG_ON(!nents);
613
614 ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS,
615 gfp_mask, scsi_sg_alloc);
616 if (unlikely(ret))
617 __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS,
618 scsi_sg_free);
619
620 return ret;
621}
622
623static void scsi_free_sgtable(struct scsi_data_buffer *sdb)
624{
625 __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free);
626}
627
628static void __scsi_release_buffers(struct scsi_cmnd *cmd, int do_bidi_check)
629{
630
631 if (cmd->sdb.table.nents)
632 scsi_free_sgtable(&cmd->sdb);
633
634 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
635
636 if (do_bidi_check && scsi_bidi_cmnd(cmd)) {
637 struct scsi_data_buffer *bidi_sdb =
638 cmd->request->next_rq->special;
639 scsi_free_sgtable(bidi_sdb);
640 kmem_cache_free(scsi_sdb_cache, bidi_sdb);
641 cmd->request->next_rq->special = NULL;
642 }
643
644 if (scsi_prot_sg_count(cmd))
645 scsi_free_sgtable(cmd->prot_sdb);
646}
647
648/*
649 * Function: scsi_release_buffers()
650 *
651 * Purpose: Completion processing for block device I/O requests.
652 *
653 * Arguments: cmd - command that we are bailing.
654 *
655 * Lock status: Assumed that no lock is held upon entry.
656 *
657 * Returns: Nothing
658 *
659 * Notes: In the event that an upper level driver rejects a
660 * command, we must release resources allocated during
661 * the __init_io() function. Primarily this would involve
662 * the scatter-gather table, and potentially any bounce
663 * buffers.
664 */
665void scsi_release_buffers(struct scsi_cmnd *cmd)
666{
667 __scsi_release_buffers(cmd, 1);
668}
669EXPORT_SYMBOL(scsi_release_buffers);
670
671/**
672 * __scsi_error_from_host_byte - translate SCSI error code into errno
673 * @cmd: SCSI command (unused)
674 * @result: scsi error code
675 *
676 * Translate SCSI error code into standard UNIX errno.
677 * Return values:
678 * -ENOLINK temporary transport failure
679 * -EREMOTEIO permanent target failure, do not retry
680 * -EBADE permanent nexus failure, retry on other path
681 * -ENOSPC No write space available
682 * -ENODATA Medium error
683 * -EIO unspecified I/O error
684 */
685static int __scsi_error_from_host_byte(struct scsi_cmnd *cmd, int result)
686{
687 int error = 0;
688
689 switch(host_byte(result)) {
690 case DID_TRANSPORT_FAILFAST:
691 error = -ENOLINK;
692 break;
693 case DID_TARGET_FAILURE:
694 set_host_byte(cmd, DID_OK);
695 error = -EREMOTEIO;
696 break;
697 case DID_NEXUS_FAILURE:
698 set_host_byte(cmd, DID_OK);
699 error = -EBADE;
700 break;
701 case DID_ALLOC_FAILURE:
702 set_host_byte(cmd, DID_OK);
703 error = -ENOSPC;
704 break;
705 case DID_MEDIUM_ERROR:
706 set_host_byte(cmd, DID_OK);
707 error = -ENODATA;
708 break;
709 default:
710 error = -EIO;
711 break;
712 }
713
714 return error;
715}
716
717/*
718 * Function: scsi_io_completion()
719 *
720 * Purpose: Completion processing for block device I/O requests.
721 *
722 * Arguments: cmd - command that is finished.
723 *
724 * Lock status: Assumed that no lock is held upon entry.
725 *
726 * Returns: Nothing
727 *
728 * Notes: This function is matched in terms of capabilities to
729 * the function that created the scatter-gather list.
730 * In other words, if there are no bounce buffers
731 * (the normal case for most drivers), we don't need
732 * the logic to deal with cleaning up afterwards.
733 *
734 * We must call scsi_end_request(). This will finish off
735 * the specified number of sectors. If we are done, the
736 * command block will be released and the queue function
737 * will be goosed. If we are not done then we have to
738 * figure out what to do next:
739 *
740 * a) We can call scsi_requeue_command(). The request
741 * will be unprepared and put back on the queue. Then
742 * a new command will be created for it. This should
743 * be used if we made forward progress, or if we want
744 * to switch from READ(10) to READ(6) for example.
745 *
746 * b) We can call scsi_queue_insert(). The request will
747 * be put back on the queue and retried using the same
748 * command as before, possibly after a delay.
749 *
750 * c) We can call blk_end_request() with -EIO to fail
751 * the remainder of the request.
752 */
753void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
754{
755 int result = cmd->result;
756 struct request_queue *q = cmd->device->request_queue;
757 struct request *req = cmd->request;
758 int error = 0;
759 struct scsi_sense_hdr sshdr;
760 int sense_valid = 0;
761 int sense_deferred = 0;
762 enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,
763 ACTION_DELAYED_RETRY} action;
764 char *description = NULL;
765 unsigned long wait_for = (cmd->allowed + 1) * req->timeout;
766
767 if (result) {
768 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
769 if (sense_valid)
770 sense_deferred = scsi_sense_is_deferred(&sshdr);
771 }
772
773 if (req->cmd_type == REQ_TYPE_BLOCK_PC) { /* SG_IO ioctl from block level */
774 if (result) {
775 if (sense_valid && req->sense) {
776 /*
777 * SG_IO wants current and deferred errors
778 */
779 int len = 8 + cmd->sense_buffer[7];
780
781 if (len > SCSI_SENSE_BUFFERSIZE)
782 len = SCSI_SENSE_BUFFERSIZE;
783 memcpy(req->sense, cmd->sense_buffer, len);
784 req->sense_len = len;
785 }
786 if (!sense_deferred)
787 error = __scsi_error_from_host_byte(cmd, result);
788 }
789 /*
790 * __scsi_error_from_host_byte may have reset the host_byte
791 */
792 req->errors = cmd->result;
793
794 req->resid_len = scsi_get_resid(cmd);
795
796 if (scsi_bidi_cmnd(cmd)) {
797 /*
798 * Bidi commands Must be complete as a whole,
799 * both sides at once.
800 */
801 req->next_rq->resid_len = scsi_in(cmd)->resid;
802
803 scsi_release_buffers(cmd);
804 blk_end_request_all(req, 0);
805
806 scsi_next_command(cmd);
807 return;
808 }
809 }
810
811 /* no bidi support for !REQ_TYPE_BLOCK_PC yet */
812 BUG_ON(blk_bidi_rq(req));
813
814 /*
815 * Next deal with any sectors which we were able to correctly
816 * handle.
817 */
818 SCSI_LOG_HLCOMPLETE(1, printk("%u sectors total, "
819 "%d bytes done.\n",
820 blk_rq_sectors(req), good_bytes));
821
822 /*
823 * Recovered errors need reporting, but they're always treated
824 * as success, so fiddle the result code here. For BLOCK_PC
825 * we already took a copy of the original into rq->errors which
826 * is what gets returned to the user
827 */
828 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
829 /* if ATA PASS-THROUGH INFORMATION AVAILABLE skip
830 * print since caller wants ATA registers. Only occurs on
831 * SCSI ATA PASS_THROUGH commands when CK_COND=1
832 */
833 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
834 ;
835 else if (!(req->cmd_flags & REQ_QUIET))
836 scsi_print_sense("", cmd);
837 result = 0;
838 /* BLOCK_PC may have set error */
839 error = 0;
840 }
841
842 /*
843 * A number of bytes were successfully read. If there
844 * are leftovers and there is some kind of error
845 * (result != 0), retry the rest.
846 */
847 if (scsi_end_request(cmd, error, good_bytes, result == 0) == NULL)
848 return;
849
850 error = __scsi_error_from_host_byte(cmd, result);
851
852 if (host_byte(result) == DID_RESET) {
853 /* Third party bus reset or reset for error recovery
854 * reasons. Just retry the command and see what
855 * happens.
856 */
857 action = ACTION_RETRY;
858 } else if (sense_valid && !sense_deferred) {
859 switch (sshdr.sense_key) {
860 case UNIT_ATTENTION:
861 if (cmd->device->removable) {
862 /* Detected disc change. Set a bit
863 * and quietly refuse further access.
864 */
865 cmd->device->changed = 1;
866 description = "Media Changed";
867 action = ACTION_FAIL;
868 } else {
869 /* Must have been a power glitch, or a
870 * bus reset. Could not have been a
871 * media change, so we just retry the
872 * command and see what happens.
873 */
874 action = ACTION_RETRY;
875 }
876 break;
877 case ILLEGAL_REQUEST:
878 /* If we had an ILLEGAL REQUEST returned, then
879 * we may have performed an unsupported
880 * command. The only thing this should be
881 * would be a ten byte read where only a six
882 * byte read was supported. Also, on a system
883 * where READ CAPACITY failed, we may have
884 * read past the end of the disk.
885 */
886 if ((cmd->device->use_10_for_rw &&
887 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
888 (cmd->cmnd[0] == READ_10 ||
889 cmd->cmnd[0] == WRITE_10)) {
890 /* This will issue a new 6-byte command. */
891 cmd->device->use_10_for_rw = 0;
892 action = ACTION_REPREP;
893 } else if (sshdr.asc == 0x10) /* DIX */ {
894 description = "Host Data Integrity Failure";
895 action = ACTION_FAIL;
896 error = -EILSEQ;
897 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
898 } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
899 switch (cmd->cmnd[0]) {
900 case UNMAP:
901 description = "Discard failure";
902 break;
903 case WRITE_SAME:
904 case WRITE_SAME_16:
905 if (cmd->cmnd[1] & 0x8)
906 description = "Discard failure";
907 else
908 description =
909 "Write same failure";
910 break;
911 default:
912 description = "Invalid command failure";
913 break;
914 }
915 action = ACTION_FAIL;
916 error = -EREMOTEIO;
917 } else
918 action = ACTION_FAIL;
919 break;
920 case ABORTED_COMMAND:
921 action = ACTION_FAIL;
922 if (sshdr.asc == 0x10) { /* DIF */
923 description = "Target Data Integrity Failure";
924 error = -EILSEQ;
925 }
926 break;
927 case NOT_READY:
928 /* If the device is in the process of becoming
929 * ready, or has a temporary blockage, retry.
930 */
931 if (sshdr.asc == 0x04) {
932 switch (sshdr.ascq) {
933 case 0x01: /* becoming ready */
934 case 0x04: /* format in progress */
935 case 0x05: /* rebuild in progress */
936 case 0x06: /* recalculation in progress */
937 case 0x07: /* operation in progress */
938 case 0x08: /* Long write in progress */
939 case 0x09: /* self test in progress */
940 case 0x14: /* space allocation in progress */
941 action = ACTION_DELAYED_RETRY;
942 break;
943 default:
944 description = "Device not ready";
945 action = ACTION_FAIL;
946 break;
947 }
948 } else {
949 description = "Device not ready";
950 action = ACTION_FAIL;
951 }
952 break;
953 case VOLUME_OVERFLOW:
954 /* See SSC3rXX or current. */
955 action = ACTION_FAIL;
956 break;
957 default:
958 description = "Unhandled sense code";
959 action = ACTION_FAIL;
960 break;
961 }
962 } else {
963 description = "Unhandled error code";
964 action = ACTION_FAIL;
965 }
966
967 if (action != ACTION_FAIL &&
968 time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
969 action = ACTION_FAIL;
970 description = "Command timed out";
971 }
972
973 switch (action) {
974 case ACTION_FAIL:
975 /* Give up and fail the remainder of the request */
976 scsi_release_buffers(cmd);
977 if (!(req->cmd_flags & REQ_QUIET)) {
978 if (description)
979 scmd_printk(KERN_INFO, cmd, "%s\n",
980 description);
981 scsi_print_result(cmd);
982 if (driver_byte(result) & DRIVER_SENSE)
983 scsi_print_sense("", cmd);
984 scsi_print_command(cmd);
985 }
986 if (blk_end_request_err(req, error))
987 scsi_requeue_command(q, cmd);
988 else
989 scsi_next_command(cmd);
990 break;
991 case ACTION_REPREP:
992 /* Unprep the request and put it back at the head of the queue.
993 * A new command will be prepared and issued.
994 */
995 scsi_release_buffers(cmd);
996 scsi_requeue_command(q, cmd);
997 break;
998 case ACTION_RETRY:
999 /* Retry the same command immediately */
1000 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, 0);
1001 break;
1002 case ACTION_DELAYED_RETRY:
1003 /* Retry the same command after a delay */
1004 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, 0);
1005 break;
1006 }
1007}
1008
1009static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb,
1010 gfp_t gfp_mask)
1011{
1012 int count;
1013
1014 /*
1015 * If sg table allocation fails, requeue request later.
1016 */
1017 if (unlikely(scsi_alloc_sgtable(sdb, req->nr_phys_segments,
1018 gfp_mask))) {
1019 return BLKPREP_DEFER;
1020 }
1021
1022 req->buffer = NULL;
1023
1024 /*
1025 * Next, walk the list, and fill in the addresses and sizes of
1026 * each segment.
1027 */
1028 count = blk_rq_map_sg(req->q, req, sdb->table.sgl);
1029 BUG_ON(count > sdb->table.nents);
1030 sdb->table.nents = count;
1031 sdb->length = blk_rq_bytes(req);
1032 return BLKPREP_OK;
1033}
1034
1035/*
1036 * Function: scsi_init_io()
1037 *
1038 * Purpose: SCSI I/O initialize function.
1039 *
1040 * Arguments: cmd - Command descriptor we wish to initialize
1041 *
1042 * Returns: 0 on success
1043 * BLKPREP_DEFER if the failure is retryable
1044 * BLKPREP_KILL if the failure is fatal
1045 */
1046int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask)
1047{
1048 struct scsi_device *sdev = cmd->device;
1049 struct request *rq = cmd->request;
1050
1051 int error = scsi_init_sgtable(rq, &cmd->sdb, gfp_mask);
1052 if (error)
1053 goto err_exit;
1054
1055 if (blk_bidi_rq(rq)) {
1056 struct scsi_data_buffer *bidi_sdb = kmem_cache_zalloc(
1057 scsi_sdb_cache, GFP_ATOMIC);
1058 if (!bidi_sdb) {
1059 error = BLKPREP_DEFER;
1060 goto err_exit;
1061 }
1062
1063 rq->next_rq->special = bidi_sdb;
1064 error = scsi_init_sgtable(rq->next_rq, bidi_sdb, GFP_ATOMIC);
1065 if (error)
1066 goto err_exit;
1067 }
1068
1069 if (blk_integrity_rq(rq)) {
1070 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1071 int ivecs, count;
1072
1073 BUG_ON(prot_sdb == NULL);
1074 ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
1075
1076 if (scsi_alloc_sgtable(prot_sdb, ivecs, gfp_mask)) {
1077 error = BLKPREP_DEFER;
1078 goto err_exit;
1079 }
1080
1081 count = blk_rq_map_integrity_sg(rq->q, rq->bio,
1082 prot_sdb->table.sgl);
1083 BUG_ON(unlikely(count > ivecs));
1084 BUG_ON(unlikely(count > queue_max_integrity_segments(rq->q)));
1085
1086 cmd->prot_sdb = prot_sdb;
1087 cmd->prot_sdb->table.nents = count;
1088 }
1089
1090 return BLKPREP_OK ;
1091
1092err_exit:
1093 scsi_release_buffers(cmd);
1094 cmd->request->special = NULL;
1095 scsi_put_command(cmd);
1096 put_device(&sdev->sdev_gendev);
1097 return error;
1098}
1099EXPORT_SYMBOL(scsi_init_io);
1100
1101static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev,
1102 struct request *req)
1103{
1104 struct scsi_cmnd *cmd;
1105
1106 if (!req->special) {
1107 /* Bail if we can't get a reference to the device */
1108 if (!get_device(&sdev->sdev_gendev))
1109 return NULL;
1110
1111 cmd = scsi_get_command(sdev, GFP_ATOMIC);
1112 if (unlikely(!cmd)) {
1113 put_device(&sdev->sdev_gendev);
1114 return NULL;
1115 }
1116 req->special = cmd;
1117 } else {
1118 cmd = req->special;
1119 }
1120
1121 /* pull a tag out of the request if we have one */
1122 cmd->tag = req->tag;
1123 cmd->request = req;
1124
1125 cmd->cmnd = req->cmd;
1126 cmd->prot_op = SCSI_PROT_NORMAL;
1127
1128 return cmd;
1129}
1130
1131int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
1132{
1133 struct scsi_cmnd *cmd;
1134 int ret = scsi_prep_state_check(sdev, req);
1135
1136 if (ret != BLKPREP_OK)
1137 return ret;
1138
1139 cmd = scsi_get_cmd_from_req(sdev, req);
1140 if (unlikely(!cmd))
1141 return BLKPREP_DEFER;
1142
1143 /*
1144 * BLOCK_PC requests may transfer data, in which case they must
1145 * a bio attached to them. Or they might contain a SCSI command
1146 * that does not transfer data, in which case they may optionally
1147 * submit a request without an attached bio.
1148 */
1149 if (req->bio) {
1150 int ret;
1151
1152 BUG_ON(!req->nr_phys_segments);
1153
1154 ret = scsi_init_io(cmd, GFP_ATOMIC);
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 req->buffer = NULL;
1162 }
1163
1164 cmd->cmd_len = req->cmd_len;
1165 if (!blk_rq_bytes(req))
1166 cmd->sc_data_direction = DMA_NONE;
1167 else if (rq_data_dir(req) == WRITE)
1168 cmd->sc_data_direction = DMA_TO_DEVICE;
1169 else
1170 cmd->sc_data_direction = DMA_FROM_DEVICE;
1171
1172 cmd->transfersize = blk_rq_bytes(req);
1173 cmd->allowed = req->retries;
1174 return BLKPREP_OK;
1175}
1176EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd);
1177
1178/*
1179 * Setup a REQ_TYPE_FS command. These are simple read/write request
1180 * from filesystems that still need to be translated to SCSI CDBs from
1181 * the ULD.
1182 */
1183int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
1184{
1185 struct scsi_cmnd *cmd;
1186 int ret = scsi_prep_state_check(sdev, req);
1187
1188 if (ret != BLKPREP_OK)
1189 return ret;
1190
1191 if (unlikely(sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh
1192 && sdev->scsi_dh_data->scsi_dh->prep_fn)) {
1193 ret = sdev->scsi_dh_data->scsi_dh->prep_fn(sdev, req);
1194 if (ret != BLKPREP_OK)
1195 return ret;
1196 }
1197
1198 /*
1199 * Filesystem requests must transfer data.
1200 */
1201 BUG_ON(!req->nr_phys_segments);
1202
1203 cmd = scsi_get_cmd_from_req(sdev, req);
1204 if (unlikely(!cmd))
1205 return BLKPREP_DEFER;
1206
1207 memset(cmd->cmnd, 0, BLK_MAX_CDB);
1208 return scsi_init_io(cmd, GFP_ATOMIC);
1209}
1210EXPORT_SYMBOL(scsi_setup_fs_cmnd);
1211
1212int scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
1213{
1214 int ret = BLKPREP_OK;
1215
1216 /*
1217 * If the device is not in running state we will reject some
1218 * or all commands.
1219 */
1220 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
1221 switch (sdev->sdev_state) {
1222 case SDEV_OFFLINE:
1223 case SDEV_TRANSPORT_OFFLINE:
1224 /*
1225 * If the device is offline we refuse to process any
1226 * commands. The device must be brought online
1227 * before trying any recovery commands.
1228 */
1229 sdev_printk(KERN_ERR, sdev,
1230 "rejecting I/O to offline device\n");
1231 ret = BLKPREP_KILL;
1232 break;
1233 case SDEV_DEL:
1234 /*
1235 * If the device is fully deleted, we refuse to
1236 * process any commands as well.
1237 */
1238 sdev_printk(KERN_ERR, sdev,
1239 "rejecting I/O to dead device\n");
1240 ret = BLKPREP_KILL;
1241 break;
1242 case SDEV_QUIESCE:
1243 case SDEV_BLOCK:
1244 case SDEV_CREATED_BLOCK:
1245 /*
1246 * If the devices is blocked we defer normal commands.
1247 */
1248 if (!(req->cmd_flags & REQ_PREEMPT))
1249 ret = BLKPREP_DEFER;
1250 break;
1251 default:
1252 /*
1253 * For any other not fully online state we only allow
1254 * special commands. In particular any user initiated
1255 * command is not allowed.
1256 */
1257 if (!(req->cmd_flags & REQ_PREEMPT))
1258 ret = BLKPREP_KILL;
1259 break;
1260 }
1261 }
1262 return ret;
1263}
1264EXPORT_SYMBOL(scsi_prep_state_check);
1265
1266int scsi_prep_return(struct request_queue *q, struct request *req, int ret)
1267{
1268 struct scsi_device *sdev = q->queuedata;
1269
1270 switch (ret) {
1271 case BLKPREP_KILL:
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 (sdev->device_busy == 0)
1289 blk_delay_queue(q, SCSI_QUEUE_DELAY);
1290 break;
1291 default:
1292 req->cmd_flags |= REQ_DONTPREP;
1293 }
1294
1295 return ret;
1296}
1297EXPORT_SYMBOL(scsi_prep_return);
1298
1299int scsi_prep_fn(struct request_queue *q, struct request *req)
1300{
1301 struct scsi_device *sdev = q->queuedata;
1302 int ret = BLKPREP_KILL;
1303
1304 if (req->cmd_type == REQ_TYPE_BLOCK_PC)
1305 ret = scsi_setup_blk_pc_cmnd(sdev, req);
1306 return scsi_prep_return(q, req, ret);
1307}
1308EXPORT_SYMBOL(scsi_prep_fn);
1309
1310/*
1311 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1312 * return 0.
1313 *
1314 * Called with the queue_lock held.
1315 */
1316static inline int scsi_dev_queue_ready(struct request_queue *q,
1317 struct scsi_device *sdev)
1318{
1319 if (sdev->device_busy == 0 && sdev->device_blocked) {
1320 /*
1321 * unblock after device_blocked iterates to zero
1322 */
1323 if (--sdev->device_blocked == 0) {
1324 SCSI_LOG_MLQUEUE(3,
1325 sdev_printk(KERN_INFO, sdev,
1326 "unblocking device at zero depth\n"));
1327 } else {
1328 blk_delay_queue(q, SCSI_QUEUE_DELAY);
1329 return 0;
1330 }
1331 }
1332 if (scsi_device_is_busy(sdev))
1333 return 0;
1334
1335 return 1;
1336}
1337
1338
1339/*
1340 * scsi_target_queue_ready: checks if there we can send commands to target
1341 * @sdev: scsi device on starget to check.
1342 *
1343 * Called with the host lock held.
1344 */
1345static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1346 struct scsi_device *sdev)
1347{
1348 struct scsi_target *starget = scsi_target(sdev);
1349
1350 if (starget->single_lun) {
1351 if (starget->starget_sdev_user &&
1352 starget->starget_sdev_user != sdev)
1353 return 0;
1354 starget->starget_sdev_user = sdev;
1355 }
1356
1357 if (starget->target_busy == 0 && starget->target_blocked) {
1358 /*
1359 * unblock after target_blocked iterates to zero
1360 */
1361 if (--starget->target_blocked == 0) {
1362 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1363 "unblocking target at zero depth\n"));
1364 } else
1365 return 0;
1366 }
1367
1368 if (scsi_target_is_busy(starget)) {
1369 list_move_tail(&sdev->starved_entry, &shost->starved_list);
1370 return 0;
1371 }
1372
1373 return 1;
1374}
1375
1376/*
1377 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1378 * return 0. We must end up running the queue again whenever 0 is
1379 * returned, else IO can hang.
1380 *
1381 * Called with host_lock held.
1382 */
1383static inline int scsi_host_queue_ready(struct request_queue *q,
1384 struct Scsi_Host *shost,
1385 struct scsi_device *sdev)
1386{
1387 if (scsi_host_in_recovery(shost))
1388 return 0;
1389 if (shost->host_busy == 0 && shost->host_blocked) {
1390 /*
1391 * unblock after host_blocked iterates to zero
1392 */
1393 if (--shost->host_blocked == 0) {
1394 SCSI_LOG_MLQUEUE(3,
1395 printk("scsi%d unblocking host at zero depth\n",
1396 shost->host_no));
1397 } else {
1398 return 0;
1399 }
1400 }
1401 if (scsi_host_is_busy(shost)) {
1402 if (list_empty(&sdev->starved_entry))
1403 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1404 return 0;
1405 }
1406
1407 /* We're OK to process the command, so we can't be starved */
1408 if (!list_empty(&sdev->starved_entry))
1409 list_del_init(&sdev->starved_entry);
1410
1411 return 1;
1412}
1413
1414/*
1415 * Busy state exporting function for request stacking drivers.
1416 *
1417 * For efficiency, no lock is taken to check the busy state of
1418 * shost/starget/sdev, since the returned value is not guaranteed and
1419 * may be changed after request stacking drivers call the function,
1420 * regardless of taking lock or not.
1421 *
1422 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1423 * needs to return 'not busy'. Otherwise, request stacking drivers
1424 * may hold requests forever.
1425 */
1426static int scsi_lld_busy(struct request_queue *q)
1427{
1428 struct scsi_device *sdev = q->queuedata;
1429 struct Scsi_Host *shost;
1430
1431 if (blk_queue_dying(q))
1432 return 0;
1433
1434 shost = sdev->host;
1435
1436 /*
1437 * Ignore host/starget busy state.
1438 * Since block layer does not have a concept of fairness across
1439 * multiple queues, congestion of host/starget needs to be handled
1440 * in SCSI layer.
1441 */
1442 if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
1443 return 1;
1444
1445 return 0;
1446}
1447
1448/*
1449 * Kill a request for a dead device
1450 */
1451static void scsi_kill_request(struct request *req, struct request_queue *q)
1452{
1453 struct scsi_cmnd *cmd = req->special;
1454 struct scsi_device *sdev;
1455 struct scsi_target *starget;
1456 struct Scsi_Host *shost;
1457
1458 blk_start_request(req);
1459
1460 scmd_printk(KERN_INFO, cmd, "killing request\n");
1461
1462 sdev = cmd->device;
1463 starget = scsi_target(sdev);
1464 shost = sdev->host;
1465 scsi_init_cmd_errh(cmd);
1466 cmd->result = DID_NO_CONNECT << 16;
1467 atomic_inc(&cmd->device->iorequest_cnt);
1468
1469 /*
1470 * SCSI request completion path will do scsi_device_unbusy(),
1471 * bump busy counts. To bump the counters, we need to dance
1472 * with the locks as normal issue path does.
1473 */
1474 sdev->device_busy++;
1475 spin_unlock(sdev->request_queue->queue_lock);
1476 spin_lock(shost->host_lock);
1477 shost->host_busy++;
1478 starget->target_busy++;
1479 spin_unlock(shost->host_lock);
1480 spin_lock(sdev->request_queue->queue_lock);
1481
1482 blk_complete_request(req);
1483}
1484
1485static void scsi_softirq_done(struct request *rq)
1486{
1487 struct scsi_cmnd *cmd = rq->special;
1488 unsigned long wait_for = (cmd->allowed + 1) * rq->timeout;
1489 int disposition;
1490
1491 INIT_LIST_HEAD(&cmd->eh_entry);
1492
1493 atomic_inc(&cmd->device->iodone_cnt);
1494 if (cmd->result)
1495 atomic_inc(&cmd->device->ioerr_cnt);
1496
1497 disposition = scsi_decide_disposition(cmd);
1498 if (disposition != SUCCESS &&
1499 time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
1500 sdev_printk(KERN_ERR, cmd->device,
1501 "timing out command, waited %lus\n",
1502 wait_for/HZ);
1503 disposition = SUCCESS;
1504 }
1505
1506 scsi_log_completion(cmd, disposition);
1507
1508 switch (disposition) {
1509 case SUCCESS:
1510 scsi_finish_command(cmd);
1511 break;
1512 case NEEDS_RETRY:
1513 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
1514 break;
1515 case ADD_TO_MLQUEUE:
1516 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1517 break;
1518 default:
1519 if (!scsi_eh_scmd_add(cmd, 0))
1520 scsi_finish_command(cmd);
1521 }
1522}
1523
1524/*
1525 * Function: scsi_request_fn()
1526 *
1527 * Purpose: Main strategy routine for SCSI.
1528 *
1529 * Arguments: q - Pointer to actual queue.
1530 *
1531 * Returns: Nothing
1532 *
1533 * Lock status: IO request lock assumed to be held when called.
1534 */
1535static void scsi_request_fn(struct request_queue *q)
1536 __releases(q->queue_lock)
1537 __acquires(q->queue_lock)
1538{
1539 struct scsi_device *sdev = q->queuedata;
1540 struct Scsi_Host *shost;
1541 struct scsi_cmnd *cmd;
1542 struct request *req;
1543
1544 /*
1545 * To start with, we keep looping until the queue is empty, or until
1546 * the host is no longer able to accept any more requests.
1547 */
1548 shost = sdev->host;
1549 for (;;) {
1550 int rtn;
1551 /*
1552 * get next queueable request. We do this early to make sure
1553 * that the request is fully prepared even if we cannot
1554 * accept it.
1555 */
1556 req = blk_peek_request(q);
1557 if (!req || !scsi_dev_queue_ready(q, sdev))
1558 break;
1559
1560 if (unlikely(!scsi_device_online(sdev))) {
1561 sdev_printk(KERN_ERR, sdev,
1562 "rejecting I/O to offline device\n");
1563 scsi_kill_request(req, q);
1564 continue;
1565 }
1566
1567
1568 /*
1569 * Remove the request from the request list.
1570 */
1571 if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req)))
1572 blk_start_request(req);
1573 sdev->device_busy++;
1574
1575 spin_unlock(q->queue_lock);
1576 cmd = req->special;
1577 if (unlikely(cmd == NULL)) {
1578 printk(KERN_CRIT "impossible request in %s.\n"
1579 "please mail a stack trace to "
1580 "linux-scsi@vger.kernel.org\n",
1581 __func__);
1582 blk_dump_rq_flags(req, "foo");
1583 BUG();
1584 }
1585 spin_lock(shost->host_lock);
1586
1587 /*
1588 * We hit this when the driver is using a host wide
1589 * tag map. For device level tag maps the queue_depth check
1590 * in the device ready fn would prevent us from trying
1591 * to allocate a tag. Since the map is a shared host resource
1592 * we add the dev to the starved list so it eventually gets
1593 * a run when a tag is freed.
1594 */
1595 if (blk_queue_tagged(q) && !blk_rq_tagged(req)) {
1596 if (list_empty(&sdev->starved_entry))
1597 list_add_tail(&sdev->starved_entry,
1598 &shost->starved_list);
1599 goto not_ready;
1600 }
1601
1602 if (!scsi_target_queue_ready(shost, sdev))
1603 goto not_ready;
1604
1605 if (!scsi_host_queue_ready(q, shost, sdev))
1606 goto not_ready;
1607
1608 scsi_target(sdev)->target_busy++;
1609 shost->host_busy++;
1610
1611 /*
1612 * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will
1613 * take the lock again.
1614 */
1615 spin_unlock_irq(shost->host_lock);
1616
1617 /*
1618 * Finally, initialize any error handling parameters, and set up
1619 * the timers for timeouts.
1620 */
1621 scsi_init_cmd_errh(cmd);
1622
1623 /*
1624 * Dispatch the command to the low-level driver.
1625 */
1626 rtn = scsi_dispatch_cmd(cmd);
1627 spin_lock_irq(q->queue_lock);
1628 if (rtn)
1629 goto out_delay;
1630 }
1631
1632 return;
1633
1634 not_ready:
1635 spin_unlock_irq(shost->host_lock);
1636
1637 /*
1638 * lock q, handle tag, requeue req, and decrement device_busy. We
1639 * must return with queue_lock held.
1640 *
1641 * Decrementing device_busy without checking it is OK, as all such
1642 * cases (host limits or settings) should run the queue at some
1643 * later time.
1644 */
1645 spin_lock_irq(q->queue_lock);
1646 blk_requeue_request(q, req);
1647 sdev->device_busy--;
1648out_delay:
1649 if (sdev->device_busy == 0)
1650 blk_delay_queue(q, SCSI_QUEUE_DELAY);
1651}
1652
1653u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost)
1654{
1655 struct device *host_dev;
1656 u64 bounce_limit = 0xffffffff;
1657
1658 if (shost->unchecked_isa_dma)
1659 return BLK_BOUNCE_ISA;
1660 /*
1661 * Platforms with virtual-DMA translation
1662 * hardware have no practical limit.
1663 */
1664 if (!PCI_DMA_BUS_IS_PHYS)
1665 return BLK_BOUNCE_ANY;
1666
1667 host_dev = scsi_get_device(shost);
1668 if (host_dev && host_dev->dma_mask)
1669 bounce_limit = (u64)dma_max_pfn(host_dev) << PAGE_SHIFT;
1670
1671 return bounce_limit;
1672}
1673EXPORT_SYMBOL(scsi_calculate_bounce_limit);
1674
1675struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost,
1676 request_fn_proc *request_fn)
1677{
1678 struct request_queue *q;
1679 struct device *dev = shost->dma_dev;
1680
1681 q = blk_init_queue(request_fn, NULL);
1682 if (!q)
1683 return NULL;
1684
1685 /*
1686 * this limit is imposed by hardware restrictions
1687 */
1688 blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
1689 SCSI_MAX_SG_CHAIN_SEGMENTS));
1690
1691 if (scsi_host_prot_dma(shost)) {
1692 shost->sg_prot_tablesize =
1693 min_not_zero(shost->sg_prot_tablesize,
1694 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
1695 BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
1696 blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
1697 }
1698
1699 blk_queue_max_hw_sectors(q, shost->max_sectors);
1700 blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost));
1701 blk_queue_segment_boundary(q, shost->dma_boundary);
1702 dma_set_seg_boundary(dev, shost->dma_boundary);
1703
1704 blk_queue_max_segment_size(q, dma_get_max_seg_size(dev));
1705
1706 if (!shost->use_clustering)
1707 q->limits.cluster = 0;
1708
1709 /*
1710 * set a reasonable default alignment on word boundaries: the
1711 * host and device may alter it using
1712 * blk_queue_update_dma_alignment() later.
1713 */
1714 blk_queue_dma_alignment(q, 0x03);
1715
1716 return q;
1717}
1718EXPORT_SYMBOL(__scsi_alloc_queue);
1719
1720struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
1721{
1722 struct request_queue *q;
1723
1724 q = __scsi_alloc_queue(sdev->host, scsi_request_fn);
1725 if (!q)
1726 return NULL;
1727
1728 blk_queue_prep_rq(q, scsi_prep_fn);
1729 blk_queue_softirq_done(q, scsi_softirq_done);
1730 blk_queue_rq_timed_out(q, scsi_times_out);
1731 blk_queue_lld_busy(q, scsi_lld_busy);
1732 return q;
1733}
1734
1735/*
1736 * Function: scsi_block_requests()
1737 *
1738 * Purpose: Utility function used by low-level drivers to prevent further
1739 * commands from being queued to the device.
1740 *
1741 * Arguments: shost - Host in question
1742 *
1743 * Returns: Nothing
1744 *
1745 * Lock status: No locks are assumed held.
1746 *
1747 * Notes: There is no timer nor any other means by which the requests
1748 * get unblocked other than the low-level driver calling
1749 * scsi_unblock_requests().
1750 */
1751void scsi_block_requests(struct Scsi_Host *shost)
1752{
1753 shost->host_self_blocked = 1;
1754}
1755EXPORT_SYMBOL(scsi_block_requests);
1756
1757/*
1758 * Function: scsi_unblock_requests()
1759 *
1760 * Purpose: Utility function used by low-level drivers to allow further
1761 * commands from being queued to the device.
1762 *
1763 * Arguments: shost - Host in question
1764 *
1765 * Returns: Nothing
1766 *
1767 * Lock status: No locks are assumed held.
1768 *
1769 * Notes: There is no timer nor any other means by which the requests
1770 * get unblocked other than the low-level driver calling
1771 * scsi_unblock_requests().
1772 *
1773 * This is done as an API function so that changes to the
1774 * internals of the scsi mid-layer won't require wholesale
1775 * changes to drivers that use this feature.
1776 */
1777void scsi_unblock_requests(struct Scsi_Host *shost)
1778{
1779 shost->host_self_blocked = 0;
1780 scsi_run_host_queues(shost);
1781}
1782EXPORT_SYMBOL(scsi_unblock_requests);
1783
1784int __init scsi_init_queue(void)
1785{
1786 int i;
1787
1788 scsi_sdb_cache = kmem_cache_create("scsi_data_buffer",
1789 sizeof(struct scsi_data_buffer),
1790 0, 0, NULL);
1791 if (!scsi_sdb_cache) {
1792 printk(KERN_ERR "SCSI: can't init scsi sdb cache\n");
1793 return -ENOMEM;
1794 }
1795
1796 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1797 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1798 int size = sgp->size * sizeof(struct scatterlist);
1799
1800 sgp->slab = kmem_cache_create(sgp->name, size, 0,
1801 SLAB_HWCACHE_ALIGN, NULL);
1802 if (!sgp->slab) {
1803 printk(KERN_ERR "SCSI: can't init sg slab %s\n",
1804 sgp->name);
1805 goto cleanup_sdb;
1806 }
1807
1808 sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE,
1809 sgp->slab);
1810 if (!sgp->pool) {
1811 printk(KERN_ERR "SCSI: can't init sg mempool %s\n",
1812 sgp->name);
1813 goto cleanup_sdb;
1814 }
1815 }
1816
1817 return 0;
1818
1819cleanup_sdb:
1820 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1821 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1822 if (sgp->pool)
1823 mempool_destroy(sgp->pool);
1824 if (sgp->slab)
1825 kmem_cache_destroy(sgp->slab);
1826 }
1827 kmem_cache_destroy(scsi_sdb_cache);
1828
1829 return -ENOMEM;
1830}
1831
1832void scsi_exit_queue(void)
1833{
1834 int i;
1835
1836 kmem_cache_destroy(scsi_sdb_cache);
1837
1838 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1839 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1840 mempool_destroy(sgp->pool);
1841 kmem_cache_destroy(sgp->slab);
1842 }
1843}
1844
1845/**
1846 * scsi_mode_select - issue a mode select
1847 * @sdev: SCSI device to be queried
1848 * @pf: Page format bit (1 == standard, 0 == vendor specific)
1849 * @sp: Save page bit (0 == don't save, 1 == save)
1850 * @modepage: mode page being requested
1851 * @buffer: request buffer (may not be smaller than eight bytes)
1852 * @len: length of request buffer.
1853 * @timeout: command timeout
1854 * @retries: number of retries before failing
1855 * @data: returns a structure abstracting the mode header data
1856 * @sshdr: place to put sense data (or NULL if no sense to be collected).
1857 * must be SCSI_SENSE_BUFFERSIZE big.
1858 *
1859 * Returns zero if successful; negative error number or scsi
1860 * status on error
1861 *
1862 */
1863int
1864scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
1865 unsigned char *buffer, int len, int timeout, int retries,
1866 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
1867{
1868 unsigned char cmd[10];
1869 unsigned char *real_buffer;
1870 int ret;
1871
1872 memset(cmd, 0, sizeof(cmd));
1873 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
1874
1875 if (sdev->use_10_for_ms) {
1876 if (len > 65535)
1877 return -EINVAL;
1878 real_buffer = kmalloc(8 + len, GFP_KERNEL);
1879 if (!real_buffer)
1880 return -ENOMEM;
1881 memcpy(real_buffer + 8, buffer, len);
1882 len += 8;
1883 real_buffer[0] = 0;
1884 real_buffer[1] = 0;
1885 real_buffer[2] = data->medium_type;
1886 real_buffer[3] = data->device_specific;
1887 real_buffer[4] = data->longlba ? 0x01 : 0;
1888 real_buffer[5] = 0;
1889 real_buffer[6] = data->block_descriptor_length >> 8;
1890 real_buffer[7] = data->block_descriptor_length;
1891
1892 cmd[0] = MODE_SELECT_10;
1893 cmd[7] = len >> 8;
1894 cmd[8] = len;
1895 } else {
1896 if (len > 255 || data->block_descriptor_length > 255 ||
1897 data->longlba)
1898 return -EINVAL;
1899
1900 real_buffer = kmalloc(4 + len, GFP_KERNEL);
1901 if (!real_buffer)
1902 return -ENOMEM;
1903 memcpy(real_buffer + 4, buffer, len);
1904 len += 4;
1905 real_buffer[0] = 0;
1906 real_buffer[1] = data->medium_type;
1907 real_buffer[2] = data->device_specific;
1908 real_buffer[3] = data->block_descriptor_length;
1909
1910
1911 cmd[0] = MODE_SELECT;
1912 cmd[4] = len;
1913 }
1914
1915 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
1916 sshdr, timeout, retries, NULL);
1917 kfree(real_buffer);
1918 return ret;
1919}
1920EXPORT_SYMBOL_GPL(scsi_mode_select);
1921
1922/**
1923 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
1924 * @sdev: SCSI device to be queried
1925 * @dbd: set if mode sense will allow block descriptors to be returned
1926 * @modepage: mode page being requested
1927 * @buffer: request buffer (may not be smaller than eight bytes)
1928 * @len: length of request buffer.
1929 * @timeout: command timeout
1930 * @retries: number of retries before failing
1931 * @data: returns a structure abstracting the mode header data
1932 * @sshdr: place to put sense data (or NULL if no sense to be collected).
1933 * must be SCSI_SENSE_BUFFERSIZE big.
1934 *
1935 * Returns zero if unsuccessful, or the header offset (either 4
1936 * or 8 depending on whether a six or ten byte command was
1937 * issued) if successful.
1938 */
1939int
1940scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
1941 unsigned char *buffer, int len, int timeout, int retries,
1942 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
1943{
1944 unsigned char cmd[12];
1945 int use_10_for_ms;
1946 int header_length;
1947 int result;
1948 struct scsi_sense_hdr my_sshdr;
1949
1950 memset(data, 0, sizeof(*data));
1951 memset(&cmd[0], 0, 12);
1952 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
1953 cmd[2] = modepage;
1954
1955 /* caller might not be interested in sense, but we need it */
1956 if (!sshdr)
1957 sshdr = &my_sshdr;
1958
1959 retry:
1960 use_10_for_ms = sdev->use_10_for_ms;
1961
1962 if (use_10_for_ms) {
1963 if (len < 8)
1964 len = 8;
1965
1966 cmd[0] = MODE_SENSE_10;
1967 cmd[8] = len;
1968 header_length = 8;
1969 } else {
1970 if (len < 4)
1971 len = 4;
1972
1973 cmd[0] = MODE_SENSE;
1974 cmd[4] = len;
1975 header_length = 4;
1976 }
1977
1978 memset(buffer, 0, len);
1979
1980 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
1981 sshdr, timeout, retries, NULL);
1982
1983 /* This code looks awful: what it's doing is making sure an
1984 * ILLEGAL REQUEST sense return identifies the actual command
1985 * byte as the problem. MODE_SENSE commands can return
1986 * ILLEGAL REQUEST if the code page isn't supported */
1987
1988 if (use_10_for_ms && !scsi_status_is_good(result) &&
1989 (driver_byte(result) & DRIVER_SENSE)) {
1990 if (scsi_sense_valid(sshdr)) {
1991 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
1992 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
1993 /*
1994 * Invalid command operation code
1995 */
1996 sdev->use_10_for_ms = 0;
1997 goto retry;
1998 }
1999 }
2000 }
2001
2002 if(scsi_status_is_good(result)) {
2003 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
2004 (modepage == 6 || modepage == 8))) {
2005 /* Initio breakage? */
2006 header_length = 0;
2007 data->length = 13;
2008 data->medium_type = 0;
2009 data->device_specific = 0;
2010 data->longlba = 0;
2011 data->block_descriptor_length = 0;
2012 } else if(use_10_for_ms) {
2013 data->length = buffer[0]*256 + buffer[1] + 2;
2014 data->medium_type = buffer[2];
2015 data->device_specific = buffer[3];
2016 data->longlba = buffer[4] & 0x01;
2017 data->block_descriptor_length = buffer[6]*256
2018 + buffer[7];
2019 } else {
2020 data->length = buffer[0] + 1;
2021 data->medium_type = buffer[1];
2022 data->device_specific = buffer[2];
2023 data->block_descriptor_length = buffer[3];
2024 }
2025 data->header_length = header_length;
2026 }
2027
2028 return result;
2029}
2030EXPORT_SYMBOL(scsi_mode_sense);
2031
2032/**
2033 * scsi_test_unit_ready - test if unit is ready
2034 * @sdev: scsi device to change the state of.
2035 * @timeout: command timeout
2036 * @retries: number of retries before failing
2037 * @sshdr_external: Optional pointer to struct scsi_sense_hdr for
2038 * returning sense. Make sure that this is cleared before passing
2039 * in.
2040 *
2041 * Returns zero if unsuccessful or an error if TUR failed. For
2042 * removable media, UNIT_ATTENTION sets ->changed flag.
2043 **/
2044int
2045scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2046 struct scsi_sense_hdr *sshdr_external)
2047{
2048 char cmd[] = {
2049 TEST_UNIT_READY, 0, 0, 0, 0, 0,
2050 };
2051 struct scsi_sense_hdr *sshdr;
2052 int result;
2053
2054 if (!sshdr_external)
2055 sshdr = kzalloc(sizeof(*sshdr), GFP_KERNEL);
2056 else
2057 sshdr = sshdr_external;
2058
2059 /* try to eat the UNIT_ATTENTION if there are enough retries */
2060 do {
2061 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
2062 timeout, retries, NULL);
2063 if (sdev->removable && scsi_sense_valid(sshdr) &&
2064 sshdr->sense_key == UNIT_ATTENTION)
2065 sdev->changed = 1;
2066 } while (scsi_sense_valid(sshdr) &&
2067 sshdr->sense_key == UNIT_ATTENTION && --retries);
2068
2069 if (!sshdr_external)
2070 kfree(sshdr);
2071 return result;
2072}
2073EXPORT_SYMBOL(scsi_test_unit_ready);
2074
2075/**
2076 * scsi_device_set_state - Take the given device through the device state model.
2077 * @sdev: scsi device to change the state of.
2078 * @state: state to change to.
2079 *
2080 * Returns zero if unsuccessful or an error if the requested
2081 * transition is illegal.
2082 */
2083int
2084scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2085{
2086 enum scsi_device_state oldstate = sdev->sdev_state;
2087
2088 if (state == oldstate)
2089 return 0;
2090
2091 switch (state) {
2092 case SDEV_CREATED:
2093 switch (oldstate) {
2094 case SDEV_CREATED_BLOCK:
2095 break;
2096 default:
2097 goto illegal;
2098 }
2099 break;
2100
2101 case SDEV_RUNNING:
2102 switch (oldstate) {
2103 case SDEV_CREATED:
2104 case SDEV_OFFLINE:
2105 case SDEV_TRANSPORT_OFFLINE:
2106 case SDEV_QUIESCE:
2107 case SDEV_BLOCK:
2108 break;
2109 default:
2110 goto illegal;
2111 }
2112 break;
2113
2114 case SDEV_QUIESCE:
2115 switch (oldstate) {
2116 case SDEV_RUNNING:
2117 case SDEV_OFFLINE:
2118 case SDEV_TRANSPORT_OFFLINE:
2119 break;
2120 default:
2121 goto illegal;
2122 }
2123 break;
2124
2125 case SDEV_OFFLINE:
2126 case SDEV_TRANSPORT_OFFLINE:
2127 switch (oldstate) {
2128 case SDEV_CREATED:
2129 case SDEV_RUNNING:
2130 case SDEV_QUIESCE:
2131 case SDEV_BLOCK:
2132 break;
2133 default:
2134 goto illegal;
2135 }
2136 break;
2137
2138 case SDEV_BLOCK:
2139 switch (oldstate) {
2140 case SDEV_RUNNING:
2141 case SDEV_CREATED_BLOCK:
2142 break;
2143 default:
2144 goto illegal;
2145 }
2146 break;
2147
2148 case SDEV_CREATED_BLOCK:
2149 switch (oldstate) {
2150 case SDEV_CREATED:
2151 break;
2152 default:
2153 goto illegal;
2154 }
2155 break;
2156
2157 case SDEV_CANCEL:
2158 switch (oldstate) {
2159 case SDEV_CREATED:
2160 case SDEV_RUNNING:
2161 case SDEV_QUIESCE:
2162 case SDEV_OFFLINE:
2163 case SDEV_TRANSPORT_OFFLINE:
2164 case SDEV_BLOCK:
2165 break;
2166 default:
2167 goto illegal;
2168 }
2169 break;
2170
2171 case SDEV_DEL:
2172 switch (oldstate) {
2173 case SDEV_CREATED:
2174 case SDEV_RUNNING:
2175 case SDEV_OFFLINE:
2176 case SDEV_TRANSPORT_OFFLINE:
2177 case SDEV_CANCEL:
2178 case SDEV_CREATED_BLOCK:
2179 break;
2180 default:
2181 goto illegal;
2182 }
2183 break;
2184
2185 }
2186 sdev->sdev_state = state;
2187 return 0;
2188
2189 illegal:
2190 SCSI_LOG_ERROR_RECOVERY(1,
2191 sdev_printk(KERN_ERR, sdev,
2192 "Illegal state transition %s->%s\n",
2193 scsi_device_state_name(oldstate),
2194 scsi_device_state_name(state))
2195 );
2196 return -EINVAL;
2197}
2198EXPORT_SYMBOL(scsi_device_set_state);
2199
2200/**
2201 * sdev_evt_emit - emit a single SCSI device uevent
2202 * @sdev: associated SCSI device
2203 * @evt: event to emit
2204 *
2205 * Send a single uevent (scsi_event) to the associated scsi_device.
2206 */
2207static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2208{
2209 int idx = 0;
2210 char *envp[3];
2211
2212 switch (evt->evt_type) {
2213 case SDEV_EVT_MEDIA_CHANGE:
2214 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2215 break;
2216 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2217 envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2218 break;
2219 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2220 envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2221 break;
2222 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2223 envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2224 break;
2225 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2226 envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2227 break;
2228 case SDEV_EVT_LUN_CHANGE_REPORTED:
2229 envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2230 break;
2231 default:
2232 /* do nothing */
2233 break;
2234 }
2235
2236 envp[idx++] = NULL;
2237
2238 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2239}
2240
2241/**
2242 * sdev_evt_thread - send a uevent for each scsi event
2243 * @work: work struct for scsi_device
2244 *
2245 * Dispatch queued events to their associated scsi_device kobjects
2246 * as uevents.
2247 */
2248void scsi_evt_thread(struct work_struct *work)
2249{
2250 struct scsi_device *sdev;
2251 enum scsi_device_event evt_type;
2252 LIST_HEAD(event_list);
2253
2254 sdev = container_of(work, struct scsi_device, event_work);
2255
2256 for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
2257 if (test_and_clear_bit(evt_type, sdev->pending_events))
2258 sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
2259
2260 while (1) {
2261 struct scsi_event *evt;
2262 struct list_head *this, *tmp;
2263 unsigned long flags;
2264
2265 spin_lock_irqsave(&sdev->list_lock, flags);
2266 list_splice_init(&sdev->event_list, &event_list);
2267 spin_unlock_irqrestore(&sdev->list_lock, flags);
2268
2269 if (list_empty(&event_list))
2270 break;
2271
2272 list_for_each_safe(this, tmp, &event_list) {
2273 evt = list_entry(this, struct scsi_event, node);
2274 list_del(&evt->node);
2275 scsi_evt_emit(sdev, evt);
2276 kfree(evt);
2277 }
2278 }
2279}
2280
2281/**
2282 * sdev_evt_send - send asserted event to uevent thread
2283 * @sdev: scsi_device event occurred on
2284 * @evt: event to send
2285 *
2286 * Assert scsi device event asynchronously.
2287 */
2288void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2289{
2290 unsigned long flags;
2291
2292#if 0
2293 /* FIXME: currently this check eliminates all media change events
2294 * for polled devices. Need to update to discriminate between AN
2295 * and polled events */
2296 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2297 kfree(evt);
2298 return;
2299 }
2300#endif
2301
2302 spin_lock_irqsave(&sdev->list_lock, flags);
2303 list_add_tail(&evt->node, &sdev->event_list);
2304 schedule_work(&sdev->event_work);
2305 spin_unlock_irqrestore(&sdev->list_lock, flags);
2306}
2307EXPORT_SYMBOL_GPL(sdev_evt_send);
2308
2309/**
2310 * sdev_evt_alloc - allocate a new scsi event
2311 * @evt_type: type of event to allocate
2312 * @gfpflags: GFP flags for allocation
2313 *
2314 * Allocates and returns a new scsi_event.
2315 */
2316struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2317 gfp_t gfpflags)
2318{
2319 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2320 if (!evt)
2321 return NULL;
2322
2323 evt->evt_type = evt_type;
2324 INIT_LIST_HEAD(&evt->node);
2325
2326 /* evt_type-specific initialization, if any */
2327 switch (evt_type) {
2328 case SDEV_EVT_MEDIA_CHANGE:
2329 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2330 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2331 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2332 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2333 case SDEV_EVT_LUN_CHANGE_REPORTED:
2334 default:
2335 /* do nothing */
2336 break;
2337 }
2338
2339 return evt;
2340}
2341EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2342
2343/**
2344 * sdev_evt_send_simple - send asserted event to uevent thread
2345 * @sdev: scsi_device event occurred on
2346 * @evt_type: type of event to send
2347 * @gfpflags: GFP flags for allocation
2348 *
2349 * Assert scsi device event asynchronously, given an event type.
2350 */
2351void sdev_evt_send_simple(struct scsi_device *sdev,
2352 enum scsi_device_event evt_type, gfp_t gfpflags)
2353{
2354 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2355 if (!evt) {
2356 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2357 evt_type);
2358 return;
2359 }
2360
2361 sdev_evt_send(sdev, evt);
2362}
2363EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2364
2365/**
2366 * scsi_device_quiesce - Block user issued commands.
2367 * @sdev: scsi device to quiesce.
2368 *
2369 * This works by trying to transition to the SDEV_QUIESCE state
2370 * (which must be a legal transition). When the device is in this
2371 * state, only special requests will be accepted, all others will
2372 * be deferred. Since special requests may also be requeued requests,
2373 * a successful return doesn't guarantee the device will be
2374 * totally quiescent.
2375 *
2376 * Must be called with user context, may sleep.
2377 *
2378 * Returns zero if unsuccessful or an error if not.
2379 */
2380int
2381scsi_device_quiesce(struct scsi_device *sdev)
2382{
2383 int err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2384 if (err)
2385 return err;
2386
2387 scsi_run_queue(sdev->request_queue);
2388 while (sdev->device_busy) {
2389 msleep_interruptible(200);
2390 scsi_run_queue(sdev->request_queue);
2391 }
2392 return 0;
2393}
2394EXPORT_SYMBOL(scsi_device_quiesce);
2395
2396/**
2397 * scsi_device_resume - Restart user issued commands to a quiesced device.
2398 * @sdev: scsi device to resume.
2399 *
2400 * Moves the device from quiesced back to running and restarts the
2401 * queues.
2402 *
2403 * Must be called with user context, may sleep.
2404 */
2405void scsi_device_resume(struct scsi_device *sdev)
2406{
2407 /* check if the device state was mutated prior to resume, and if
2408 * so assume the state is being managed elsewhere (for example
2409 * device deleted during suspend)
2410 */
2411 if (sdev->sdev_state != SDEV_QUIESCE ||
2412 scsi_device_set_state(sdev, SDEV_RUNNING))
2413 return;
2414 scsi_run_queue(sdev->request_queue);
2415}
2416EXPORT_SYMBOL(scsi_device_resume);
2417
2418static void
2419device_quiesce_fn(struct scsi_device *sdev, void *data)
2420{
2421 scsi_device_quiesce(sdev);
2422}
2423
2424void
2425scsi_target_quiesce(struct scsi_target *starget)
2426{
2427 starget_for_each_device(starget, NULL, device_quiesce_fn);
2428}
2429EXPORT_SYMBOL(scsi_target_quiesce);
2430
2431static void
2432device_resume_fn(struct scsi_device *sdev, void *data)
2433{
2434 scsi_device_resume(sdev);
2435}
2436
2437void
2438scsi_target_resume(struct scsi_target *starget)
2439{
2440 starget_for_each_device(starget, NULL, device_resume_fn);
2441}
2442EXPORT_SYMBOL(scsi_target_resume);
2443
2444/**
2445 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state
2446 * @sdev: device to block
2447 *
2448 * Block request made by scsi lld's to temporarily stop all
2449 * scsi commands on the specified device. Called from interrupt
2450 * or normal process context.
2451 *
2452 * Returns zero if successful or error if not
2453 *
2454 * Notes:
2455 * This routine transitions the device to the SDEV_BLOCK state
2456 * (which must be a legal transition). When the device is in this
2457 * state, all commands are deferred until the scsi lld reenables
2458 * the device with scsi_device_unblock or device_block_tmo fires.
2459 */
2460int
2461scsi_internal_device_block(struct scsi_device *sdev)
2462{
2463 struct request_queue *q = sdev->request_queue;
2464 unsigned long flags;
2465 int err = 0;
2466
2467 err = scsi_device_set_state(sdev, SDEV_BLOCK);
2468 if (err) {
2469 err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2470
2471 if (err)
2472 return err;
2473 }
2474
2475 /*
2476 * The device has transitioned to SDEV_BLOCK. Stop the
2477 * block layer from calling the midlayer with this device's
2478 * request queue.
2479 */
2480 spin_lock_irqsave(q->queue_lock, flags);
2481 blk_stop_queue(q);
2482 spin_unlock_irqrestore(q->queue_lock, flags);
2483
2484 return 0;
2485}
2486EXPORT_SYMBOL_GPL(scsi_internal_device_block);
2487
2488/**
2489 * scsi_internal_device_unblock - resume a device after a block request
2490 * @sdev: device to resume
2491 * @new_state: state to set devices to after unblocking
2492 *
2493 * Called by scsi lld's or the midlayer to restart the device queue
2494 * for the previously suspended scsi device. Called from interrupt or
2495 * normal process context.
2496 *
2497 * Returns zero if successful or error if not.
2498 *
2499 * Notes:
2500 * This routine transitions the device to the SDEV_RUNNING state
2501 * or to one of the offline states (which must be a legal transition)
2502 * allowing the midlayer to goose the queue for this device.
2503 */
2504int
2505scsi_internal_device_unblock(struct scsi_device *sdev,
2506 enum scsi_device_state new_state)
2507{
2508 struct request_queue *q = sdev->request_queue;
2509 unsigned long flags;
2510
2511 /*
2512 * Try to transition the scsi device to SDEV_RUNNING or one of the
2513 * offlined states and goose the device queue if successful.
2514 */
2515 if ((sdev->sdev_state == SDEV_BLOCK) ||
2516 (sdev->sdev_state == SDEV_TRANSPORT_OFFLINE))
2517 sdev->sdev_state = new_state;
2518 else if (sdev->sdev_state == SDEV_CREATED_BLOCK) {
2519 if (new_state == SDEV_TRANSPORT_OFFLINE ||
2520 new_state == SDEV_OFFLINE)
2521 sdev->sdev_state = new_state;
2522 else
2523 sdev->sdev_state = SDEV_CREATED;
2524 } else if (sdev->sdev_state != SDEV_CANCEL &&
2525 sdev->sdev_state != SDEV_OFFLINE)
2526 return -EINVAL;
2527
2528 spin_lock_irqsave(q->queue_lock, flags);
2529 blk_start_queue(q);
2530 spin_unlock_irqrestore(q->queue_lock, flags);
2531
2532 return 0;
2533}
2534EXPORT_SYMBOL_GPL(scsi_internal_device_unblock);
2535
2536static void
2537device_block(struct scsi_device *sdev, void *data)
2538{
2539 scsi_internal_device_block(sdev);
2540}
2541
2542static int
2543target_block(struct device *dev, void *data)
2544{
2545 if (scsi_is_target_device(dev))
2546 starget_for_each_device(to_scsi_target(dev), NULL,
2547 device_block);
2548 return 0;
2549}
2550
2551void
2552scsi_target_block(struct device *dev)
2553{
2554 if (scsi_is_target_device(dev))
2555 starget_for_each_device(to_scsi_target(dev), NULL,
2556 device_block);
2557 else
2558 device_for_each_child(dev, NULL, target_block);
2559}
2560EXPORT_SYMBOL_GPL(scsi_target_block);
2561
2562static void
2563device_unblock(struct scsi_device *sdev, void *data)
2564{
2565 scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
2566}
2567
2568static int
2569target_unblock(struct device *dev, void *data)
2570{
2571 if (scsi_is_target_device(dev))
2572 starget_for_each_device(to_scsi_target(dev), data,
2573 device_unblock);
2574 return 0;
2575}
2576
2577void
2578scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
2579{
2580 if (scsi_is_target_device(dev))
2581 starget_for_each_device(to_scsi_target(dev), &new_state,
2582 device_unblock);
2583 else
2584 device_for_each_child(dev, &new_state, target_unblock);
2585}
2586EXPORT_SYMBOL_GPL(scsi_target_unblock);
2587
2588/**
2589 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
2590 * @sgl: scatter-gather list
2591 * @sg_count: number of segments in sg
2592 * @offset: offset in bytes into sg, on return offset into the mapped area
2593 * @len: bytes to map, on return number of bytes mapped
2594 *
2595 * Returns virtual address of the start of the mapped page
2596 */
2597void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
2598 size_t *offset, size_t *len)
2599{
2600 int i;
2601 size_t sg_len = 0, len_complete = 0;
2602 struct scatterlist *sg;
2603 struct page *page;
2604
2605 WARN_ON(!irqs_disabled());
2606
2607 for_each_sg(sgl, sg, sg_count, i) {
2608 len_complete = sg_len; /* Complete sg-entries */
2609 sg_len += sg->length;
2610 if (sg_len > *offset)
2611 break;
2612 }
2613
2614 if (unlikely(i == sg_count)) {
2615 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
2616 "elements %d\n",
2617 __func__, sg_len, *offset, sg_count);
2618 WARN_ON(1);
2619 return NULL;
2620 }
2621
2622 /* Offset starting from the beginning of first page in this sg-entry */
2623 *offset = *offset - len_complete + sg->offset;
2624
2625 /* Assumption: contiguous pages can be accessed as "page + i" */
2626 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
2627 *offset &= ~PAGE_MASK;
2628
2629 /* Bytes in this sg-entry from *offset to the end of the page */
2630 sg_len = PAGE_SIZE - *offset;
2631 if (*len > sg_len)
2632 *len = sg_len;
2633
2634 return kmap_atomic(page);
2635}
2636EXPORT_SYMBOL(scsi_kmap_atomic_sg);
2637
2638/**
2639 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
2640 * @virt: virtual address to be unmapped
2641 */
2642void scsi_kunmap_atomic_sg(void *virt)
2643{
2644 kunmap_atomic(virt);
2645}
2646EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
2647
2648void sdev_disable_disk_events(struct scsi_device *sdev)
2649{
2650 atomic_inc(&sdev->disk_events_disable_depth);
2651}
2652EXPORT_SYMBOL(sdev_disable_disk_events);
2653
2654void sdev_enable_disk_events(struct scsi_device *sdev)
2655{
2656 if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0))
2657 return;
2658 atomic_dec(&sdev->disk_events_disable_depth);
2659}
2660EXPORT_SYMBOL(sdev_enable_disk_events);