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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 1991, 1992 Linus Torvalds
4 * Copyright (C) 1994, Karl Keyte: Added support for disk statistics
5 * Elevator latency, (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
6 * Queue request tables / lock, selectable elevator, Jens Axboe <axboe@suse.de>
7 * kernel-doc documentation started by NeilBrown <neilb@cse.unsw.edu.au>
8 * - July2000
9 * bio rewrite, highmem i/o, etc, Jens Axboe <axboe@suse.de> - may 2001
10 */
11
12/*
13 * This handles all read/write requests to block devices
14 */
15#include <linux/kernel.h>
16#include <linux/module.h>
17#include <linux/bio.h>
18#include <linux/blkdev.h>
19#include <linux/blk-pm.h>
20#include <linux/blk-integrity.h>
21#include <linux/highmem.h>
22#include <linux/mm.h>
23#include <linux/pagemap.h>
24#include <linux/kernel_stat.h>
25#include <linux/string.h>
26#include <linux/init.h>
27#include <linux/completion.h>
28#include <linux/slab.h>
29#include <linux/swap.h>
30#include <linux/writeback.h>
31#include <linux/task_io_accounting_ops.h>
32#include <linux/fault-inject.h>
33#include <linux/list_sort.h>
34#include <linux/delay.h>
35#include <linux/ratelimit.h>
36#include <linux/pm_runtime.h>
37#include <linux/t10-pi.h>
38#include <linux/debugfs.h>
39#include <linux/bpf.h>
40#include <linux/part_stat.h>
41#include <linux/sched/sysctl.h>
42#include <linux/blk-crypto.h>
43
44#define CREATE_TRACE_POINTS
45#include <trace/events/block.h>
46
47#include "blk.h"
48#include "blk-mq-sched.h"
49#include "blk-pm.h"
50#include "blk-cgroup.h"
51#include "blk-throttle.h"
52
53struct dentry *blk_debugfs_root;
54
55EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap);
56EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap);
57EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete);
58EXPORT_TRACEPOINT_SYMBOL_GPL(block_split);
59EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug);
60EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_insert);
61
62static DEFINE_IDA(blk_queue_ida);
63
64/*
65 * For queue allocation
66 */
67static struct kmem_cache *blk_requestq_cachep;
68
69/*
70 * Controlling structure to kblockd
71 */
72static struct workqueue_struct *kblockd_workqueue;
73
74/**
75 * blk_queue_flag_set - atomically set a queue flag
76 * @flag: flag to be set
77 * @q: request queue
78 */
79void blk_queue_flag_set(unsigned int flag, struct request_queue *q)
80{
81 set_bit(flag, &q->queue_flags);
82}
83EXPORT_SYMBOL(blk_queue_flag_set);
84
85/**
86 * blk_queue_flag_clear - atomically clear a queue flag
87 * @flag: flag to be cleared
88 * @q: request queue
89 */
90void blk_queue_flag_clear(unsigned int flag, struct request_queue *q)
91{
92 clear_bit(flag, &q->queue_flags);
93}
94EXPORT_SYMBOL(blk_queue_flag_clear);
95
96/**
97 * blk_queue_flag_test_and_set - atomically test and set a queue flag
98 * @flag: flag to be set
99 * @q: request queue
100 *
101 * Returns the previous value of @flag - 0 if the flag was not set and 1 if
102 * the flag was already set.
103 */
104bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q)
105{
106 return test_and_set_bit(flag, &q->queue_flags);
107}
108EXPORT_SYMBOL_GPL(blk_queue_flag_test_and_set);
109
110#define REQ_OP_NAME(name) [REQ_OP_##name] = #name
111static const char *const blk_op_name[] = {
112 REQ_OP_NAME(READ),
113 REQ_OP_NAME(WRITE),
114 REQ_OP_NAME(FLUSH),
115 REQ_OP_NAME(DISCARD),
116 REQ_OP_NAME(SECURE_ERASE),
117 REQ_OP_NAME(ZONE_RESET),
118 REQ_OP_NAME(ZONE_RESET_ALL),
119 REQ_OP_NAME(ZONE_OPEN),
120 REQ_OP_NAME(ZONE_CLOSE),
121 REQ_OP_NAME(ZONE_FINISH),
122 REQ_OP_NAME(ZONE_APPEND),
123 REQ_OP_NAME(WRITE_ZEROES),
124 REQ_OP_NAME(DRV_IN),
125 REQ_OP_NAME(DRV_OUT),
126};
127#undef REQ_OP_NAME
128
129/**
130 * blk_op_str - Return string XXX in the REQ_OP_XXX.
131 * @op: REQ_OP_XXX.
132 *
133 * Description: Centralize block layer function to convert REQ_OP_XXX into
134 * string format. Useful in the debugging and tracing bio or request. For
135 * invalid REQ_OP_XXX it returns string "UNKNOWN".
136 */
137inline const char *blk_op_str(enum req_op op)
138{
139 const char *op_str = "UNKNOWN";
140
141 if (op < ARRAY_SIZE(blk_op_name) && blk_op_name[op])
142 op_str = blk_op_name[op];
143
144 return op_str;
145}
146EXPORT_SYMBOL_GPL(blk_op_str);
147
148static const struct {
149 int errno;
150 const char *name;
151} blk_errors[] = {
152 [BLK_STS_OK] = { 0, "" },
153 [BLK_STS_NOTSUPP] = { -EOPNOTSUPP, "operation not supported" },
154 [BLK_STS_TIMEOUT] = { -ETIMEDOUT, "timeout" },
155 [BLK_STS_NOSPC] = { -ENOSPC, "critical space allocation" },
156 [BLK_STS_TRANSPORT] = { -ENOLINK, "recoverable transport" },
157 [BLK_STS_TARGET] = { -EREMOTEIO, "critical target" },
158 [BLK_STS_NEXUS] = { -EBADE, "critical nexus" },
159 [BLK_STS_MEDIUM] = { -ENODATA, "critical medium" },
160 [BLK_STS_PROTECTION] = { -EILSEQ, "protection" },
161 [BLK_STS_RESOURCE] = { -ENOMEM, "kernel resource" },
162 [BLK_STS_DEV_RESOURCE] = { -EBUSY, "device resource" },
163 [BLK_STS_AGAIN] = { -EAGAIN, "nonblocking retry" },
164 [BLK_STS_OFFLINE] = { -ENODEV, "device offline" },
165
166 /* device mapper special case, should not leak out: */
167 [BLK_STS_DM_REQUEUE] = { -EREMCHG, "dm internal retry" },
168
169 /* zone device specific errors */
170 [BLK_STS_ZONE_OPEN_RESOURCE] = { -ETOOMANYREFS, "open zones exceeded" },
171 [BLK_STS_ZONE_ACTIVE_RESOURCE] = { -EOVERFLOW, "active zones exceeded" },
172
173 /* everything else not covered above: */
174 [BLK_STS_IOERR] = { -EIO, "I/O" },
175};
176
177blk_status_t errno_to_blk_status(int errno)
178{
179 int i;
180
181 for (i = 0; i < ARRAY_SIZE(blk_errors); i++) {
182 if (blk_errors[i].errno == errno)
183 return (__force blk_status_t)i;
184 }
185
186 return BLK_STS_IOERR;
187}
188EXPORT_SYMBOL_GPL(errno_to_blk_status);
189
190int blk_status_to_errno(blk_status_t status)
191{
192 int idx = (__force int)status;
193
194 if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors)))
195 return -EIO;
196 return blk_errors[idx].errno;
197}
198EXPORT_SYMBOL_GPL(blk_status_to_errno);
199
200const char *blk_status_to_str(blk_status_t status)
201{
202 int idx = (__force int)status;
203
204 if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors)))
205 return "<null>";
206 return blk_errors[idx].name;
207}
208
209/**
210 * blk_sync_queue - cancel any pending callbacks on a queue
211 * @q: the queue
212 *
213 * Description:
214 * The block layer may perform asynchronous callback activity
215 * on a queue, such as calling the unplug function after a timeout.
216 * A block device may call blk_sync_queue to ensure that any
217 * such activity is cancelled, thus allowing it to release resources
218 * that the callbacks might use. The caller must already have made sure
219 * that its ->submit_bio will not re-add plugging prior to calling
220 * this function.
221 *
222 * This function does not cancel any asynchronous activity arising
223 * out of elevator or throttling code. That would require elevator_exit()
224 * and blkcg_exit_queue() to be called with queue lock initialized.
225 *
226 */
227void blk_sync_queue(struct request_queue *q)
228{
229 del_timer_sync(&q->timeout);
230 cancel_work_sync(&q->timeout_work);
231}
232EXPORT_SYMBOL(blk_sync_queue);
233
234/**
235 * blk_set_pm_only - increment pm_only counter
236 * @q: request queue pointer
237 */
238void blk_set_pm_only(struct request_queue *q)
239{
240 atomic_inc(&q->pm_only);
241}
242EXPORT_SYMBOL_GPL(blk_set_pm_only);
243
244void blk_clear_pm_only(struct request_queue *q)
245{
246 int pm_only;
247
248 pm_only = atomic_dec_return(&q->pm_only);
249 WARN_ON_ONCE(pm_only < 0);
250 if (pm_only == 0)
251 wake_up_all(&q->mq_freeze_wq);
252}
253EXPORT_SYMBOL_GPL(blk_clear_pm_only);
254
255static void blk_free_queue_rcu(struct rcu_head *rcu_head)
256{
257 struct request_queue *q = container_of(rcu_head,
258 struct request_queue, rcu_head);
259
260 percpu_ref_exit(&q->q_usage_counter);
261 kmem_cache_free(blk_requestq_cachep, q);
262}
263
264static void blk_free_queue(struct request_queue *q)
265{
266 if (q->poll_stat)
267 blk_stat_remove_callback(q, q->poll_cb);
268 blk_stat_free_callback(q->poll_cb);
269
270 blk_free_queue_stats(q->stats);
271 kfree(q->poll_stat);
272
273 if (queue_is_mq(q))
274 blk_mq_release(q);
275
276 ida_free(&blk_queue_ida, q->id);
277 call_rcu(&q->rcu_head, blk_free_queue_rcu);
278}
279
280/**
281 * blk_put_queue - decrement the request_queue refcount
282 * @q: the request_queue structure to decrement the refcount for
283 *
284 * Decrements the refcount of the request_queue and free it when the refcount
285 * reaches 0.
286 */
287void blk_put_queue(struct request_queue *q)
288{
289 if (refcount_dec_and_test(&q->refs))
290 blk_free_queue(q);
291}
292EXPORT_SYMBOL(blk_put_queue);
293
294void blk_queue_start_drain(struct request_queue *q)
295{
296 /*
297 * When queue DYING flag is set, we need to block new req
298 * entering queue, so we call blk_freeze_queue_start() to
299 * prevent I/O from crossing blk_queue_enter().
300 */
301 blk_freeze_queue_start(q);
302 if (queue_is_mq(q))
303 blk_mq_wake_waiters(q);
304 /* Make blk_queue_enter() reexamine the DYING flag. */
305 wake_up_all(&q->mq_freeze_wq);
306}
307
308/**
309 * blk_queue_enter() - try to increase q->q_usage_counter
310 * @q: request queue pointer
311 * @flags: BLK_MQ_REQ_NOWAIT and/or BLK_MQ_REQ_PM
312 */
313int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags)
314{
315 const bool pm = flags & BLK_MQ_REQ_PM;
316
317 while (!blk_try_enter_queue(q, pm)) {
318 if (flags & BLK_MQ_REQ_NOWAIT)
319 return -EAGAIN;
320
321 /*
322 * read pair of barrier in blk_freeze_queue_start(), we need to
323 * order reading __PERCPU_REF_DEAD flag of .q_usage_counter and
324 * reading .mq_freeze_depth or queue dying flag, otherwise the
325 * following wait may never return if the two reads are
326 * reordered.
327 */
328 smp_rmb();
329 wait_event(q->mq_freeze_wq,
330 (!q->mq_freeze_depth &&
331 blk_pm_resume_queue(pm, q)) ||
332 blk_queue_dying(q));
333 if (blk_queue_dying(q))
334 return -ENODEV;
335 }
336
337 return 0;
338}
339
340int __bio_queue_enter(struct request_queue *q, struct bio *bio)
341{
342 while (!blk_try_enter_queue(q, false)) {
343 struct gendisk *disk = bio->bi_bdev->bd_disk;
344
345 if (bio->bi_opf & REQ_NOWAIT) {
346 if (test_bit(GD_DEAD, &disk->state))
347 goto dead;
348 bio_wouldblock_error(bio);
349 return -EAGAIN;
350 }
351
352 /*
353 * read pair of barrier in blk_freeze_queue_start(), we need to
354 * order reading __PERCPU_REF_DEAD flag of .q_usage_counter and
355 * reading .mq_freeze_depth or queue dying flag, otherwise the
356 * following wait may never return if the two reads are
357 * reordered.
358 */
359 smp_rmb();
360 wait_event(q->mq_freeze_wq,
361 (!q->mq_freeze_depth &&
362 blk_pm_resume_queue(false, q)) ||
363 test_bit(GD_DEAD, &disk->state));
364 if (test_bit(GD_DEAD, &disk->state))
365 goto dead;
366 }
367
368 return 0;
369dead:
370 bio_io_error(bio);
371 return -ENODEV;
372}
373
374void blk_queue_exit(struct request_queue *q)
375{
376 percpu_ref_put(&q->q_usage_counter);
377}
378
379static void blk_queue_usage_counter_release(struct percpu_ref *ref)
380{
381 struct request_queue *q =
382 container_of(ref, struct request_queue, q_usage_counter);
383
384 wake_up_all(&q->mq_freeze_wq);
385}
386
387static void blk_rq_timed_out_timer(struct timer_list *t)
388{
389 struct request_queue *q = from_timer(q, t, timeout);
390
391 kblockd_schedule_work(&q->timeout_work);
392}
393
394static void blk_timeout_work(struct work_struct *work)
395{
396}
397
398struct request_queue *blk_alloc_queue(int node_id)
399{
400 struct request_queue *q;
401
402 q = kmem_cache_alloc_node(blk_requestq_cachep, GFP_KERNEL | __GFP_ZERO,
403 node_id);
404 if (!q)
405 return NULL;
406
407 q->last_merge = NULL;
408
409 q->id = ida_alloc(&blk_queue_ida, GFP_KERNEL);
410 if (q->id < 0)
411 goto fail_q;
412
413 q->stats = blk_alloc_queue_stats();
414 if (!q->stats)
415 goto fail_id;
416
417 q->node = node_id;
418
419 atomic_set(&q->nr_active_requests_shared_tags, 0);
420
421 timer_setup(&q->timeout, blk_rq_timed_out_timer, 0);
422 INIT_WORK(&q->timeout_work, blk_timeout_work);
423 INIT_LIST_HEAD(&q->icq_list);
424
425 refcount_set(&q->refs, 1);
426 mutex_init(&q->debugfs_mutex);
427 mutex_init(&q->sysfs_lock);
428 mutex_init(&q->sysfs_dir_lock);
429 spin_lock_init(&q->queue_lock);
430
431 init_waitqueue_head(&q->mq_freeze_wq);
432 mutex_init(&q->mq_freeze_lock);
433
434 /*
435 * Init percpu_ref in atomic mode so that it's faster to shutdown.
436 * See blk_register_queue() for details.
437 */
438 if (percpu_ref_init(&q->q_usage_counter,
439 blk_queue_usage_counter_release,
440 PERCPU_REF_INIT_ATOMIC, GFP_KERNEL))
441 goto fail_stats;
442
443 blk_set_default_limits(&q->limits);
444 q->nr_requests = BLKDEV_DEFAULT_RQ;
445
446 return q;
447
448fail_stats:
449 blk_free_queue_stats(q->stats);
450fail_id:
451 ida_free(&blk_queue_ida, q->id);
452fail_q:
453 kmem_cache_free(blk_requestq_cachep, q);
454 return NULL;
455}
456
457/**
458 * blk_get_queue - increment the request_queue refcount
459 * @q: the request_queue structure to increment the refcount for
460 *
461 * Increment the refcount of the request_queue kobject.
462 *
463 * Context: Any context.
464 */
465bool blk_get_queue(struct request_queue *q)
466{
467 if (unlikely(blk_queue_dying(q)))
468 return false;
469 refcount_inc(&q->refs);
470 return true;
471}
472EXPORT_SYMBOL(blk_get_queue);
473
474#ifdef CONFIG_FAIL_MAKE_REQUEST
475
476static DECLARE_FAULT_ATTR(fail_make_request);
477
478static int __init setup_fail_make_request(char *str)
479{
480 return setup_fault_attr(&fail_make_request, str);
481}
482__setup("fail_make_request=", setup_fail_make_request);
483
484bool should_fail_request(struct block_device *part, unsigned int bytes)
485{
486 return part->bd_make_it_fail && should_fail(&fail_make_request, bytes);
487}
488
489static int __init fail_make_request_debugfs(void)
490{
491 struct dentry *dir = fault_create_debugfs_attr("fail_make_request",
492 NULL, &fail_make_request);
493
494 return PTR_ERR_OR_ZERO(dir);
495}
496
497late_initcall(fail_make_request_debugfs);
498#endif /* CONFIG_FAIL_MAKE_REQUEST */
499
500static inline void bio_check_ro(struct bio *bio)
501{
502 if (op_is_write(bio_op(bio)) && bdev_read_only(bio->bi_bdev)) {
503 if (op_is_flush(bio->bi_opf) && !bio_sectors(bio))
504 return;
505 pr_warn("Trying to write to read-only block-device %pg\n",
506 bio->bi_bdev);
507 /* Older lvm-tools actually trigger this */
508 }
509}
510
511static noinline int should_fail_bio(struct bio *bio)
512{
513 if (should_fail_request(bdev_whole(bio->bi_bdev), bio->bi_iter.bi_size))
514 return -EIO;
515 return 0;
516}
517ALLOW_ERROR_INJECTION(should_fail_bio, ERRNO);
518
519/*
520 * Check whether this bio extends beyond the end of the device or partition.
521 * This may well happen - the kernel calls bread() without checking the size of
522 * the device, e.g., when mounting a file system.
523 */
524static inline int bio_check_eod(struct bio *bio)
525{
526 sector_t maxsector = bdev_nr_sectors(bio->bi_bdev);
527 unsigned int nr_sectors = bio_sectors(bio);
528
529 if (nr_sectors && maxsector &&
530 (nr_sectors > maxsector ||
531 bio->bi_iter.bi_sector > maxsector - nr_sectors)) {
532 pr_info_ratelimited("%s: attempt to access beyond end of device\n"
533 "%pg: rw=%d, sector=%llu, nr_sectors = %u limit=%llu\n",
534 current->comm, bio->bi_bdev, bio->bi_opf,
535 bio->bi_iter.bi_sector, nr_sectors, maxsector);
536 return -EIO;
537 }
538 return 0;
539}
540
541/*
542 * Remap block n of partition p to block n+start(p) of the disk.
543 */
544static int blk_partition_remap(struct bio *bio)
545{
546 struct block_device *p = bio->bi_bdev;
547
548 if (unlikely(should_fail_request(p, bio->bi_iter.bi_size)))
549 return -EIO;
550 if (bio_sectors(bio)) {
551 bio->bi_iter.bi_sector += p->bd_start_sect;
552 trace_block_bio_remap(bio, p->bd_dev,
553 bio->bi_iter.bi_sector -
554 p->bd_start_sect);
555 }
556 bio_set_flag(bio, BIO_REMAPPED);
557 return 0;
558}
559
560/*
561 * Check write append to a zoned block device.
562 */
563static inline blk_status_t blk_check_zone_append(struct request_queue *q,
564 struct bio *bio)
565{
566 int nr_sectors = bio_sectors(bio);
567
568 /* Only applicable to zoned block devices */
569 if (!bdev_is_zoned(bio->bi_bdev))
570 return BLK_STS_NOTSUPP;
571
572 /* The bio sector must point to the start of a sequential zone */
573 if (bio->bi_iter.bi_sector & (bdev_zone_sectors(bio->bi_bdev) - 1) ||
574 !bio_zone_is_seq(bio))
575 return BLK_STS_IOERR;
576
577 /*
578 * Not allowed to cross zone boundaries. Otherwise, the BIO will be
579 * split and could result in non-contiguous sectors being written in
580 * different zones.
581 */
582 if (nr_sectors > q->limits.chunk_sectors)
583 return BLK_STS_IOERR;
584
585 /* Make sure the BIO is small enough and will not get split */
586 if (nr_sectors > q->limits.max_zone_append_sectors)
587 return BLK_STS_IOERR;
588
589 bio->bi_opf |= REQ_NOMERGE;
590
591 return BLK_STS_OK;
592}
593
594static void __submit_bio(struct bio *bio)
595{
596 struct gendisk *disk = bio->bi_bdev->bd_disk;
597
598 if (unlikely(!blk_crypto_bio_prep(&bio)))
599 return;
600
601 if (!disk->fops->submit_bio) {
602 blk_mq_submit_bio(bio);
603 } else if (likely(bio_queue_enter(bio) == 0)) {
604 disk->fops->submit_bio(bio);
605 blk_queue_exit(disk->queue);
606 }
607}
608
609/*
610 * The loop in this function may be a bit non-obvious, and so deserves some
611 * explanation:
612 *
613 * - Before entering the loop, bio->bi_next is NULL (as all callers ensure
614 * that), so we have a list with a single bio.
615 * - We pretend that we have just taken it off a longer list, so we assign
616 * bio_list to a pointer to the bio_list_on_stack, thus initialising the
617 * bio_list of new bios to be added. ->submit_bio() may indeed add some more
618 * bios through a recursive call to submit_bio_noacct. If it did, we find a
619 * non-NULL value in bio_list and re-enter the loop from the top.
620 * - In this case we really did just take the bio of the top of the list (no
621 * pretending) and so remove it from bio_list, and call into ->submit_bio()
622 * again.
623 *
624 * bio_list_on_stack[0] contains bios submitted by the current ->submit_bio.
625 * bio_list_on_stack[1] contains bios that were submitted before the current
626 * ->submit_bio, but that haven't been processed yet.
627 */
628static void __submit_bio_noacct(struct bio *bio)
629{
630 struct bio_list bio_list_on_stack[2];
631
632 BUG_ON(bio->bi_next);
633
634 bio_list_init(&bio_list_on_stack[0]);
635 current->bio_list = bio_list_on_stack;
636
637 do {
638 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
639 struct bio_list lower, same;
640
641 /*
642 * Create a fresh bio_list for all subordinate requests.
643 */
644 bio_list_on_stack[1] = bio_list_on_stack[0];
645 bio_list_init(&bio_list_on_stack[0]);
646
647 __submit_bio(bio);
648
649 /*
650 * Sort new bios into those for a lower level and those for the
651 * same level.
652 */
653 bio_list_init(&lower);
654 bio_list_init(&same);
655 while ((bio = bio_list_pop(&bio_list_on_stack[0])) != NULL)
656 if (q == bdev_get_queue(bio->bi_bdev))
657 bio_list_add(&same, bio);
658 else
659 bio_list_add(&lower, bio);
660
661 /*
662 * Now assemble so we handle the lowest level first.
663 */
664 bio_list_merge(&bio_list_on_stack[0], &lower);
665 bio_list_merge(&bio_list_on_stack[0], &same);
666 bio_list_merge(&bio_list_on_stack[0], &bio_list_on_stack[1]);
667 } while ((bio = bio_list_pop(&bio_list_on_stack[0])));
668
669 current->bio_list = NULL;
670}
671
672static void __submit_bio_noacct_mq(struct bio *bio)
673{
674 struct bio_list bio_list[2] = { };
675
676 current->bio_list = bio_list;
677
678 do {
679 __submit_bio(bio);
680 } while ((bio = bio_list_pop(&bio_list[0])));
681
682 current->bio_list = NULL;
683}
684
685void submit_bio_noacct_nocheck(struct bio *bio)
686{
687 /*
688 * We only want one ->submit_bio to be active at a time, else stack
689 * usage with stacked devices could be a problem. Use current->bio_list
690 * to collect a list of requests submited by a ->submit_bio method while
691 * it is active, and then process them after it returned.
692 */
693 if (current->bio_list)
694 bio_list_add(¤t->bio_list[0], bio);
695 else if (!bio->bi_bdev->bd_disk->fops->submit_bio)
696 __submit_bio_noacct_mq(bio);
697 else
698 __submit_bio_noacct(bio);
699}
700
701/**
702 * submit_bio_noacct - re-submit a bio to the block device layer for I/O
703 * @bio: The bio describing the location in memory and on the device.
704 *
705 * This is a version of submit_bio() that shall only be used for I/O that is
706 * resubmitted to lower level drivers by stacking block drivers. All file
707 * systems and other upper level users of the block layer should use
708 * submit_bio() instead.
709 */
710void submit_bio_noacct(struct bio *bio)
711{
712 struct block_device *bdev = bio->bi_bdev;
713 struct request_queue *q = bdev_get_queue(bdev);
714 blk_status_t status = BLK_STS_IOERR;
715 struct blk_plug *plug;
716
717 might_sleep();
718
719 plug = blk_mq_plug(bio);
720 if (plug && plug->nowait)
721 bio->bi_opf |= REQ_NOWAIT;
722
723 /*
724 * For a REQ_NOWAIT based request, return -EOPNOTSUPP
725 * if queue does not support NOWAIT.
726 */
727 if ((bio->bi_opf & REQ_NOWAIT) && !bdev_nowait(bdev))
728 goto not_supported;
729
730 if (should_fail_bio(bio))
731 goto end_io;
732 bio_check_ro(bio);
733 if (!bio_flagged(bio, BIO_REMAPPED)) {
734 if (unlikely(bio_check_eod(bio)))
735 goto end_io;
736 if (bdev->bd_partno && unlikely(blk_partition_remap(bio)))
737 goto end_io;
738 }
739
740 /*
741 * Filter flush bio's early so that bio based drivers without flush
742 * support don't have to worry about them.
743 */
744 if (op_is_flush(bio->bi_opf) &&
745 !test_bit(QUEUE_FLAG_WC, &q->queue_flags)) {
746 bio->bi_opf &= ~(REQ_PREFLUSH | REQ_FUA);
747 if (!bio_sectors(bio)) {
748 status = BLK_STS_OK;
749 goto end_io;
750 }
751 }
752
753 if (!test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
754 bio_clear_polled(bio);
755
756 switch (bio_op(bio)) {
757 case REQ_OP_DISCARD:
758 if (!bdev_max_discard_sectors(bdev))
759 goto not_supported;
760 break;
761 case REQ_OP_SECURE_ERASE:
762 if (!bdev_max_secure_erase_sectors(bdev))
763 goto not_supported;
764 break;
765 case REQ_OP_ZONE_APPEND:
766 status = blk_check_zone_append(q, bio);
767 if (status != BLK_STS_OK)
768 goto end_io;
769 break;
770 case REQ_OP_ZONE_RESET:
771 case REQ_OP_ZONE_OPEN:
772 case REQ_OP_ZONE_CLOSE:
773 case REQ_OP_ZONE_FINISH:
774 if (!bdev_is_zoned(bio->bi_bdev))
775 goto not_supported;
776 break;
777 case REQ_OP_ZONE_RESET_ALL:
778 if (!bdev_is_zoned(bio->bi_bdev) || !blk_queue_zone_resetall(q))
779 goto not_supported;
780 break;
781 case REQ_OP_WRITE_ZEROES:
782 if (!q->limits.max_write_zeroes_sectors)
783 goto not_supported;
784 break;
785 default:
786 break;
787 }
788
789 if (blk_throtl_bio(bio))
790 return;
791
792 blk_cgroup_bio_start(bio);
793 blkcg_bio_issue_init(bio);
794
795 if (!bio_flagged(bio, BIO_TRACE_COMPLETION)) {
796 trace_block_bio_queue(bio);
797 /* Now that enqueuing has been traced, we need to trace
798 * completion as well.
799 */
800 bio_set_flag(bio, BIO_TRACE_COMPLETION);
801 }
802 submit_bio_noacct_nocheck(bio);
803 return;
804
805not_supported:
806 status = BLK_STS_NOTSUPP;
807end_io:
808 bio->bi_status = status;
809 bio_endio(bio);
810}
811EXPORT_SYMBOL(submit_bio_noacct);
812
813/**
814 * submit_bio - submit a bio to the block device layer for I/O
815 * @bio: The &struct bio which describes the I/O
816 *
817 * submit_bio() is used to submit I/O requests to block devices. It is passed a
818 * fully set up &struct bio that describes the I/O that needs to be done. The
819 * bio will be send to the device described by the bi_bdev field.
820 *
821 * The success/failure status of the request, along with notification of
822 * completion, is delivered asynchronously through the ->bi_end_io() callback
823 * in @bio. The bio must NOT be touched by the caller until ->bi_end_io() has
824 * been called.
825 */
826void submit_bio(struct bio *bio)
827{
828 if (blkcg_punt_bio_submit(bio))
829 return;
830
831 if (bio_op(bio) == REQ_OP_READ) {
832 task_io_account_read(bio->bi_iter.bi_size);
833 count_vm_events(PGPGIN, bio_sectors(bio));
834 } else if (bio_op(bio) == REQ_OP_WRITE) {
835 count_vm_events(PGPGOUT, bio_sectors(bio));
836 }
837
838 submit_bio_noacct(bio);
839}
840EXPORT_SYMBOL(submit_bio);
841
842/**
843 * bio_poll - poll for BIO completions
844 * @bio: bio to poll for
845 * @iob: batches of IO
846 * @flags: BLK_POLL_* flags that control the behavior
847 *
848 * Poll for completions on queue associated with the bio. Returns number of
849 * completed entries found.
850 *
851 * Note: the caller must either be the context that submitted @bio, or
852 * be in a RCU critical section to prevent freeing of @bio.
853 */
854int bio_poll(struct bio *bio, struct io_comp_batch *iob, unsigned int flags)
855{
856 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
857 blk_qc_t cookie = READ_ONCE(bio->bi_cookie);
858 int ret = 0;
859
860 if (cookie == BLK_QC_T_NONE ||
861 !test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
862 return 0;
863
864 /*
865 * As the requests that require a zone lock are not plugged in the
866 * first place, directly accessing the plug instead of using
867 * blk_mq_plug() should not have any consequences during flushing for
868 * zoned devices.
869 */
870 blk_flush_plug(current->plug, false);
871
872 if (bio_queue_enter(bio))
873 return 0;
874 if (queue_is_mq(q)) {
875 ret = blk_mq_poll(q, cookie, iob, flags);
876 } else {
877 struct gendisk *disk = q->disk;
878
879 if (disk && disk->fops->poll_bio)
880 ret = disk->fops->poll_bio(bio, iob, flags);
881 }
882 blk_queue_exit(q);
883 return ret;
884}
885EXPORT_SYMBOL_GPL(bio_poll);
886
887/*
888 * Helper to implement file_operations.iopoll. Requires the bio to be stored
889 * in iocb->private, and cleared before freeing the bio.
890 */
891int iocb_bio_iopoll(struct kiocb *kiocb, struct io_comp_batch *iob,
892 unsigned int flags)
893{
894 struct bio *bio;
895 int ret = 0;
896
897 /*
898 * Note: the bio cache only uses SLAB_TYPESAFE_BY_RCU, so bio can
899 * point to a freshly allocated bio at this point. If that happens
900 * we have a few cases to consider:
901 *
902 * 1) the bio is beeing initialized and bi_bdev is NULL. We can just
903 * simply nothing in this case
904 * 2) the bio points to a not poll enabled device. bio_poll will catch
905 * this and return 0
906 * 3) the bio points to a poll capable device, including but not
907 * limited to the one that the original bio pointed to. In this
908 * case we will call into the actual poll method and poll for I/O,
909 * even if we don't need to, but it won't cause harm either.
910 *
911 * For cases 2) and 3) above the RCU grace period ensures that bi_bdev
912 * is still allocated. Because partitions hold a reference to the whole
913 * device bdev and thus disk, the disk is also still valid. Grabbing
914 * a reference to the queue in bio_poll() ensures the hctxs and requests
915 * are still valid as well.
916 */
917 rcu_read_lock();
918 bio = READ_ONCE(kiocb->private);
919 if (bio && bio->bi_bdev)
920 ret = bio_poll(bio, iob, flags);
921 rcu_read_unlock();
922
923 return ret;
924}
925EXPORT_SYMBOL_GPL(iocb_bio_iopoll);
926
927void update_io_ticks(struct block_device *part, unsigned long now, bool end)
928{
929 unsigned long stamp;
930again:
931 stamp = READ_ONCE(part->bd_stamp);
932 if (unlikely(time_after(now, stamp))) {
933 if (likely(try_cmpxchg(&part->bd_stamp, &stamp, now)))
934 __part_stat_add(part, io_ticks, end ? now - stamp : 1);
935 }
936 if (part->bd_partno) {
937 part = bdev_whole(part);
938 goto again;
939 }
940}
941
942unsigned long bdev_start_io_acct(struct block_device *bdev,
943 unsigned int sectors, enum req_op op,
944 unsigned long start_time)
945{
946 const int sgrp = op_stat_group(op);
947
948 part_stat_lock();
949 update_io_ticks(bdev, start_time, false);
950 part_stat_inc(bdev, ios[sgrp]);
951 part_stat_add(bdev, sectors[sgrp], sectors);
952 part_stat_local_inc(bdev, in_flight[op_is_write(op)]);
953 part_stat_unlock();
954
955 return start_time;
956}
957EXPORT_SYMBOL(bdev_start_io_acct);
958
959/**
960 * bio_start_io_acct - start I/O accounting for bio based drivers
961 * @bio: bio to start account for
962 *
963 * Returns the start time that should be passed back to bio_end_io_acct().
964 */
965unsigned long bio_start_io_acct(struct bio *bio)
966{
967 return bdev_start_io_acct(bio->bi_bdev, bio_sectors(bio),
968 bio_op(bio), jiffies);
969}
970EXPORT_SYMBOL_GPL(bio_start_io_acct);
971
972void bdev_end_io_acct(struct block_device *bdev, enum req_op op,
973 unsigned long start_time)
974{
975 const int sgrp = op_stat_group(op);
976 unsigned long now = READ_ONCE(jiffies);
977 unsigned long duration = now - start_time;
978
979 part_stat_lock();
980 update_io_ticks(bdev, now, true);
981 part_stat_add(bdev, nsecs[sgrp], jiffies_to_nsecs(duration));
982 part_stat_local_dec(bdev, in_flight[op_is_write(op)]);
983 part_stat_unlock();
984}
985EXPORT_SYMBOL(bdev_end_io_acct);
986
987void bio_end_io_acct_remapped(struct bio *bio, unsigned long start_time,
988 struct block_device *orig_bdev)
989{
990 bdev_end_io_acct(orig_bdev, bio_op(bio), start_time);
991}
992EXPORT_SYMBOL_GPL(bio_end_io_acct_remapped);
993
994/**
995 * blk_lld_busy - Check if underlying low-level drivers of a device are busy
996 * @q : the queue of the device being checked
997 *
998 * Description:
999 * Check if underlying low-level drivers of a device are busy.
1000 * If the drivers want to export their busy state, they must set own
1001 * exporting function using blk_queue_lld_busy() first.
1002 *
1003 * Basically, this function is used only by request stacking drivers
1004 * to stop dispatching requests to underlying devices when underlying
1005 * devices are busy. This behavior helps more I/O merging on the queue
1006 * of the request stacking driver and prevents I/O throughput regression
1007 * on burst I/O load.
1008 *
1009 * Return:
1010 * 0 - Not busy (The request stacking driver should dispatch request)
1011 * 1 - Busy (The request stacking driver should stop dispatching request)
1012 */
1013int blk_lld_busy(struct request_queue *q)
1014{
1015 if (queue_is_mq(q) && q->mq_ops->busy)
1016 return q->mq_ops->busy(q);
1017
1018 return 0;
1019}
1020EXPORT_SYMBOL_GPL(blk_lld_busy);
1021
1022int kblockd_schedule_work(struct work_struct *work)
1023{
1024 return queue_work(kblockd_workqueue, work);
1025}
1026EXPORT_SYMBOL(kblockd_schedule_work);
1027
1028int kblockd_mod_delayed_work_on(int cpu, struct delayed_work *dwork,
1029 unsigned long delay)
1030{
1031 return mod_delayed_work_on(cpu, kblockd_workqueue, dwork, delay);
1032}
1033EXPORT_SYMBOL(kblockd_mod_delayed_work_on);
1034
1035void blk_start_plug_nr_ios(struct blk_plug *plug, unsigned short nr_ios)
1036{
1037 struct task_struct *tsk = current;
1038
1039 /*
1040 * If this is a nested plug, don't actually assign it.
1041 */
1042 if (tsk->plug)
1043 return;
1044
1045 plug->mq_list = NULL;
1046 plug->cached_rq = NULL;
1047 plug->nr_ios = min_t(unsigned short, nr_ios, BLK_MAX_REQUEST_COUNT);
1048 plug->rq_count = 0;
1049 plug->multiple_queues = false;
1050 plug->has_elevator = false;
1051 plug->nowait = false;
1052 INIT_LIST_HEAD(&plug->cb_list);
1053
1054 /*
1055 * Store ordering should not be needed here, since a potential
1056 * preempt will imply a full memory barrier
1057 */
1058 tsk->plug = plug;
1059}
1060
1061/**
1062 * blk_start_plug - initialize blk_plug and track it inside the task_struct
1063 * @plug: The &struct blk_plug that needs to be initialized
1064 *
1065 * Description:
1066 * blk_start_plug() indicates to the block layer an intent by the caller
1067 * to submit multiple I/O requests in a batch. The block layer may use
1068 * this hint to defer submitting I/Os from the caller until blk_finish_plug()
1069 * is called. However, the block layer may choose to submit requests
1070 * before a call to blk_finish_plug() if the number of queued I/Os
1071 * exceeds %BLK_MAX_REQUEST_COUNT, or if the size of the I/O is larger than
1072 * %BLK_PLUG_FLUSH_SIZE. The queued I/Os may also be submitted early if
1073 * the task schedules (see below).
1074 *
1075 * Tracking blk_plug inside the task_struct will help with auto-flushing the
1076 * pending I/O should the task end up blocking between blk_start_plug() and
1077 * blk_finish_plug(). This is important from a performance perspective, but
1078 * also ensures that we don't deadlock. For instance, if the task is blocking
1079 * for a memory allocation, memory reclaim could end up wanting to free a
1080 * page belonging to that request that is currently residing in our private
1081 * plug. By flushing the pending I/O when the process goes to sleep, we avoid
1082 * this kind of deadlock.
1083 */
1084void blk_start_plug(struct blk_plug *plug)
1085{
1086 blk_start_plug_nr_ios(plug, 1);
1087}
1088EXPORT_SYMBOL(blk_start_plug);
1089
1090static void flush_plug_callbacks(struct blk_plug *plug, bool from_schedule)
1091{
1092 LIST_HEAD(callbacks);
1093
1094 while (!list_empty(&plug->cb_list)) {
1095 list_splice_init(&plug->cb_list, &callbacks);
1096
1097 while (!list_empty(&callbacks)) {
1098 struct blk_plug_cb *cb = list_first_entry(&callbacks,
1099 struct blk_plug_cb,
1100 list);
1101 list_del(&cb->list);
1102 cb->callback(cb, from_schedule);
1103 }
1104 }
1105}
1106
1107struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug, void *data,
1108 int size)
1109{
1110 struct blk_plug *plug = current->plug;
1111 struct blk_plug_cb *cb;
1112
1113 if (!plug)
1114 return NULL;
1115
1116 list_for_each_entry(cb, &plug->cb_list, list)
1117 if (cb->callback == unplug && cb->data == data)
1118 return cb;
1119
1120 /* Not currently on the callback list */
1121 BUG_ON(size < sizeof(*cb));
1122 cb = kzalloc(size, GFP_ATOMIC);
1123 if (cb) {
1124 cb->data = data;
1125 cb->callback = unplug;
1126 list_add(&cb->list, &plug->cb_list);
1127 }
1128 return cb;
1129}
1130EXPORT_SYMBOL(blk_check_plugged);
1131
1132void __blk_flush_plug(struct blk_plug *plug, bool from_schedule)
1133{
1134 if (!list_empty(&plug->cb_list))
1135 flush_plug_callbacks(plug, from_schedule);
1136 if (!rq_list_empty(plug->mq_list))
1137 blk_mq_flush_plug_list(plug, from_schedule);
1138 /*
1139 * Unconditionally flush out cached requests, even if the unplug
1140 * event came from schedule. Since we know hold references to the
1141 * queue for cached requests, we don't want a blocked task holding
1142 * up a queue freeze/quiesce event.
1143 */
1144 if (unlikely(!rq_list_empty(plug->cached_rq)))
1145 blk_mq_free_plug_rqs(plug);
1146}
1147
1148/**
1149 * blk_finish_plug - mark the end of a batch of submitted I/O
1150 * @plug: The &struct blk_plug passed to blk_start_plug()
1151 *
1152 * Description:
1153 * Indicate that a batch of I/O submissions is complete. This function
1154 * must be paired with an initial call to blk_start_plug(). The intent
1155 * is to allow the block layer to optimize I/O submission. See the
1156 * documentation for blk_start_plug() for more information.
1157 */
1158void blk_finish_plug(struct blk_plug *plug)
1159{
1160 if (plug == current->plug) {
1161 __blk_flush_plug(plug, false);
1162 current->plug = NULL;
1163 }
1164}
1165EXPORT_SYMBOL(blk_finish_plug);
1166
1167void blk_io_schedule(void)
1168{
1169 /* Prevent hang_check timer from firing at us during very long I/O */
1170 unsigned long timeout = sysctl_hung_task_timeout_secs * HZ / 2;
1171
1172 if (timeout)
1173 io_schedule_timeout(timeout);
1174 else
1175 io_schedule();
1176}
1177EXPORT_SYMBOL_GPL(blk_io_schedule);
1178
1179int __init blk_dev_init(void)
1180{
1181 BUILD_BUG_ON((__force u32)REQ_OP_LAST >= (1 << REQ_OP_BITS));
1182 BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 *
1183 sizeof_field(struct request, cmd_flags));
1184 BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 *
1185 sizeof_field(struct bio, bi_opf));
1186
1187 /* used for unplugging and affects IO latency/throughput - HIGHPRI */
1188 kblockd_workqueue = alloc_workqueue("kblockd",
1189 WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
1190 if (!kblockd_workqueue)
1191 panic("Failed to create kblockd\n");
1192
1193 blk_requestq_cachep = kmem_cache_create("request_queue",
1194 sizeof(struct request_queue), 0, SLAB_PANIC, NULL);
1195
1196 blk_debugfs_root = debugfs_create_dir("block", NULL);
1197
1198 return 0;
1199}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 1991, 1992 Linus Torvalds
4 * Copyright (C) 1994, Karl Keyte: Added support for disk statistics
5 * Elevator latency, (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
6 * Queue request tables / lock, selectable elevator, Jens Axboe <axboe@suse.de>
7 * kernel-doc documentation started by NeilBrown <neilb@cse.unsw.edu.au>
8 * - July2000
9 * bio rewrite, highmem i/o, etc, Jens Axboe <axboe@suse.de> - may 2001
10 */
11
12/*
13 * This handles all read/write requests to block devices
14 */
15#include <linux/kernel.h>
16#include <linux/module.h>
17#include <linux/backing-dev.h>
18#include <linux/bio.h>
19#include <linux/blkdev.h>
20#include <linux/blk-mq.h>
21#include <linux/blk-pm.h>
22#include <linux/highmem.h>
23#include <linux/mm.h>
24#include <linux/pagemap.h>
25#include <linux/kernel_stat.h>
26#include <linux/string.h>
27#include <linux/init.h>
28#include <linux/completion.h>
29#include <linux/slab.h>
30#include <linux/swap.h>
31#include <linux/writeback.h>
32#include <linux/task_io_accounting_ops.h>
33#include <linux/fault-inject.h>
34#include <linux/list_sort.h>
35#include <linux/delay.h>
36#include <linux/ratelimit.h>
37#include <linux/pm_runtime.h>
38#include <linux/blk-cgroup.h>
39#include <linux/t10-pi.h>
40#include <linux/debugfs.h>
41#include <linux/bpf.h>
42#include <linux/psi.h>
43#include <linux/sched/sysctl.h>
44#include <linux/blk-crypto.h>
45
46#define CREATE_TRACE_POINTS
47#include <trace/events/block.h>
48
49#include "blk.h"
50#include "blk-mq.h"
51#include "blk-mq-sched.h"
52#include "blk-pm.h"
53#include "blk-rq-qos.h"
54
55struct dentry *blk_debugfs_root;
56
57EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap);
58EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap);
59EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete);
60EXPORT_TRACEPOINT_SYMBOL_GPL(block_split);
61EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug);
62EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_insert);
63
64DEFINE_IDA(blk_queue_ida);
65
66/*
67 * For queue allocation
68 */
69struct kmem_cache *blk_requestq_cachep;
70
71/*
72 * Controlling structure to kblockd
73 */
74static struct workqueue_struct *kblockd_workqueue;
75
76/**
77 * blk_queue_flag_set - atomically set a queue flag
78 * @flag: flag to be set
79 * @q: request queue
80 */
81void blk_queue_flag_set(unsigned int flag, struct request_queue *q)
82{
83 set_bit(flag, &q->queue_flags);
84}
85EXPORT_SYMBOL(blk_queue_flag_set);
86
87/**
88 * blk_queue_flag_clear - atomically clear a queue flag
89 * @flag: flag to be cleared
90 * @q: request queue
91 */
92void blk_queue_flag_clear(unsigned int flag, struct request_queue *q)
93{
94 clear_bit(flag, &q->queue_flags);
95}
96EXPORT_SYMBOL(blk_queue_flag_clear);
97
98/**
99 * blk_queue_flag_test_and_set - atomically test and set a queue flag
100 * @flag: flag to be set
101 * @q: request queue
102 *
103 * Returns the previous value of @flag - 0 if the flag was not set and 1 if
104 * the flag was already set.
105 */
106bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q)
107{
108 return test_and_set_bit(flag, &q->queue_flags);
109}
110EXPORT_SYMBOL_GPL(blk_queue_flag_test_and_set);
111
112void blk_rq_init(struct request_queue *q, struct request *rq)
113{
114 memset(rq, 0, sizeof(*rq));
115
116 INIT_LIST_HEAD(&rq->queuelist);
117 rq->q = q;
118 rq->__sector = (sector_t) -1;
119 INIT_HLIST_NODE(&rq->hash);
120 RB_CLEAR_NODE(&rq->rb_node);
121 rq->tag = BLK_MQ_NO_TAG;
122 rq->internal_tag = BLK_MQ_NO_TAG;
123 rq->start_time_ns = ktime_get_ns();
124 rq->part = NULL;
125 blk_crypto_rq_set_defaults(rq);
126}
127EXPORT_SYMBOL(blk_rq_init);
128
129#define REQ_OP_NAME(name) [REQ_OP_##name] = #name
130static const char *const blk_op_name[] = {
131 REQ_OP_NAME(READ),
132 REQ_OP_NAME(WRITE),
133 REQ_OP_NAME(FLUSH),
134 REQ_OP_NAME(DISCARD),
135 REQ_OP_NAME(SECURE_ERASE),
136 REQ_OP_NAME(ZONE_RESET),
137 REQ_OP_NAME(ZONE_RESET_ALL),
138 REQ_OP_NAME(ZONE_OPEN),
139 REQ_OP_NAME(ZONE_CLOSE),
140 REQ_OP_NAME(ZONE_FINISH),
141 REQ_OP_NAME(ZONE_APPEND),
142 REQ_OP_NAME(WRITE_SAME),
143 REQ_OP_NAME(WRITE_ZEROES),
144 REQ_OP_NAME(DRV_IN),
145 REQ_OP_NAME(DRV_OUT),
146};
147#undef REQ_OP_NAME
148
149/**
150 * blk_op_str - Return string XXX in the REQ_OP_XXX.
151 * @op: REQ_OP_XXX.
152 *
153 * Description: Centralize block layer function to convert REQ_OP_XXX into
154 * string format. Useful in the debugging and tracing bio or request. For
155 * invalid REQ_OP_XXX it returns string "UNKNOWN".
156 */
157inline const char *blk_op_str(unsigned int op)
158{
159 const char *op_str = "UNKNOWN";
160
161 if (op < ARRAY_SIZE(blk_op_name) && blk_op_name[op])
162 op_str = blk_op_name[op];
163
164 return op_str;
165}
166EXPORT_SYMBOL_GPL(blk_op_str);
167
168static const struct {
169 int errno;
170 const char *name;
171} blk_errors[] = {
172 [BLK_STS_OK] = { 0, "" },
173 [BLK_STS_NOTSUPP] = { -EOPNOTSUPP, "operation not supported" },
174 [BLK_STS_TIMEOUT] = { -ETIMEDOUT, "timeout" },
175 [BLK_STS_NOSPC] = { -ENOSPC, "critical space allocation" },
176 [BLK_STS_TRANSPORT] = { -ENOLINK, "recoverable transport" },
177 [BLK_STS_TARGET] = { -EREMOTEIO, "critical target" },
178 [BLK_STS_NEXUS] = { -EBADE, "critical nexus" },
179 [BLK_STS_MEDIUM] = { -ENODATA, "critical medium" },
180 [BLK_STS_PROTECTION] = { -EILSEQ, "protection" },
181 [BLK_STS_RESOURCE] = { -ENOMEM, "kernel resource" },
182 [BLK_STS_DEV_RESOURCE] = { -EBUSY, "device resource" },
183 [BLK_STS_AGAIN] = { -EAGAIN, "nonblocking retry" },
184
185 /* device mapper special case, should not leak out: */
186 [BLK_STS_DM_REQUEUE] = { -EREMCHG, "dm internal retry" },
187
188 /* zone device specific errors */
189 [BLK_STS_ZONE_OPEN_RESOURCE] = { -ETOOMANYREFS, "open zones exceeded" },
190 [BLK_STS_ZONE_ACTIVE_RESOURCE] = { -EOVERFLOW, "active zones exceeded" },
191
192 /* everything else not covered above: */
193 [BLK_STS_IOERR] = { -EIO, "I/O" },
194};
195
196blk_status_t errno_to_blk_status(int errno)
197{
198 int i;
199
200 for (i = 0; i < ARRAY_SIZE(blk_errors); i++) {
201 if (blk_errors[i].errno == errno)
202 return (__force blk_status_t)i;
203 }
204
205 return BLK_STS_IOERR;
206}
207EXPORT_SYMBOL_GPL(errno_to_blk_status);
208
209int blk_status_to_errno(blk_status_t status)
210{
211 int idx = (__force int)status;
212
213 if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors)))
214 return -EIO;
215 return blk_errors[idx].errno;
216}
217EXPORT_SYMBOL_GPL(blk_status_to_errno);
218
219static void print_req_error(struct request *req, blk_status_t status,
220 const char *caller)
221{
222 int idx = (__force int)status;
223
224 if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors)))
225 return;
226
227 printk_ratelimited(KERN_ERR
228 "%s: %s error, dev %s, sector %llu op 0x%x:(%s) flags 0x%x "
229 "phys_seg %u prio class %u\n",
230 caller, blk_errors[idx].name,
231 req->rq_disk ? req->rq_disk->disk_name : "?",
232 blk_rq_pos(req), req_op(req), blk_op_str(req_op(req)),
233 req->cmd_flags & ~REQ_OP_MASK,
234 req->nr_phys_segments,
235 IOPRIO_PRIO_CLASS(req->ioprio));
236}
237
238static void req_bio_endio(struct request *rq, struct bio *bio,
239 unsigned int nbytes, blk_status_t error)
240{
241 if (error)
242 bio->bi_status = error;
243
244 if (unlikely(rq->rq_flags & RQF_QUIET))
245 bio_set_flag(bio, BIO_QUIET);
246
247 bio_advance(bio, nbytes);
248
249 if (req_op(rq) == REQ_OP_ZONE_APPEND && error == BLK_STS_OK) {
250 /*
251 * Partial zone append completions cannot be supported as the
252 * BIO fragments may end up not being written sequentially.
253 */
254 if (bio->bi_iter.bi_size)
255 bio->bi_status = BLK_STS_IOERR;
256 else
257 bio->bi_iter.bi_sector = rq->__sector;
258 }
259
260 /* don't actually finish bio if it's part of flush sequence */
261 if (bio->bi_iter.bi_size == 0 && !(rq->rq_flags & RQF_FLUSH_SEQ))
262 bio_endio(bio);
263}
264
265void blk_dump_rq_flags(struct request *rq, char *msg)
266{
267 printk(KERN_INFO "%s: dev %s: flags=%llx\n", msg,
268 rq->rq_disk ? rq->rq_disk->disk_name : "?",
269 (unsigned long long) rq->cmd_flags);
270
271 printk(KERN_INFO " sector %llu, nr/cnr %u/%u\n",
272 (unsigned long long)blk_rq_pos(rq),
273 blk_rq_sectors(rq), blk_rq_cur_sectors(rq));
274 printk(KERN_INFO " bio %p, biotail %p, len %u\n",
275 rq->bio, rq->biotail, blk_rq_bytes(rq));
276}
277EXPORT_SYMBOL(blk_dump_rq_flags);
278
279/**
280 * blk_sync_queue - cancel any pending callbacks on a queue
281 * @q: the queue
282 *
283 * Description:
284 * The block layer may perform asynchronous callback activity
285 * on a queue, such as calling the unplug function after a timeout.
286 * A block device may call blk_sync_queue to ensure that any
287 * such activity is cancelled, thus allowing it to release resources
288 * that the callbacks might use. The caller must already have made sure
289 * that its ->submit_bio will not re-add plugging prior to calling
290 * this function.
291 *
292 * This function does not cancel any asynchronous activity arising
293 * out of elevator or throttling code. That would require elevator_exit()
294 * and blkcg_exit_queue() to be called with queue lock initialized.
295 *
296 */
297void blk_sync_queue(struct request_queue *q)
298{
299 del_timer_sync(&q->timeout);
300 cancel_work_sync(&q->timeout_work);
301}
302EXPORT_SYMBOL(blk_sync_queue);
303
304/**
305 * blk_set_pm_only - increment pm_only counter
306 * @q: request queue pointer
307 */
308void blk_set_pm_only(struct request_queue *q)
309{
310 atomic_inc(&q->pm_only);
311}
312EXPORT_SYMBOL_GPL(blk_set_pm_only);
313
314void blk_clear_pm_only(struct request_queue *q)
315{
316 int pm_only;
317
318 pm_only = atomic_dec_return(&q->pm_only);
319 WARN_ON_ONCE(pm_only < 0);
320 if (pm_only == 0)
321 wake_up_all(&q->mq_freeze_wq);
322}
323EXPORT_SYMBOL_GPL(blk_clear_pm_only);
324
325/**
326 * blk_put_queue - decrement the request_queue refcount
327 * @q: the request_queue structure to decrement the refcount for
328 *
329 * Decrements the refcount of the request_queue kobject. When this reaches 0
330 * we'll have blk_release_queue() called.
331 *
332 * Context: Any context, but the last reference must not be dropped from
333 * atomic context.
334 */
335void blk_put_queue(struct request_queue *q)
336{
337 kobject_put(&q->kobj);
338}
339EXPORT_SYMBOL(blk_put_queue);
340
341void blk_set_queue_dying(struct request_queue *q)
342{
343 blk_queue_flag_set(QUEUE_FLAG_DYING, q);
344
345 /*
346 * When queue DYING flag is set, we need to block new req
347 * entering queue, so we call blk_freeze_queue_start() to
348 * prevent I/O from crossing blk_queue_enter().
349 */
350 blk_freeze_queue_start(q);
351
352 if (queue_is_mq(q))
353 blk_mq_wake_waiters(q);
354
355 /* Make blk_queue_enter() reexamine the DYING flag. */
356 wake_up_all(&q->mq_freeze_wq);
357}
358EXPORT_SYMBOL_GPL(blk_set_queue_dying);
359
360/**
361 * blk_cleanup_queue - shutdown a request queue
362 * @q: request queue to shutdown
363 *
364 * Mark @q DYING, drain all pending requests, mark @q DEAD, destroy and
365 * put it. All future requests will be failed immediately with -ENODEV.
366 *
367 * Context: can sleep
368 */
369void blk_cleanup_queue(struct request_queue *q)
370{
371 /* cannot be called from atomic context */
372 might_sleep();
373
374 WARN_ON_ONCE(blk_queue_registered(q));
375
376 /* mark @q DYING, no new request or merges will be allowed afterwards */
377 blk_set_queue_dying(q);
378
379 blk_queue_flag_set(QUEUE_FLAG_NOMERGES, q);
380 blk_queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
381
382 /*
383 * Drain all requests queued before DYING marking. Set DEAD flag to
384 * prevent that blk_mq_run_hw_queues() accesses the hardware queues
385 * after draining finished.
386 */
387 blk_freeze_queue(q);
388
389 rq_qos_exit(q);
390
391 blk_queue_flag_set(QUEUE_FLAG_DEAD, q);
392
393 /* for synchronous bio-based driver finish in-flight integrity i/o */
394 blk_flush_integrity();
395
396 /* @q won't process any more request, flush async actions */
397 del_timer_sync(&q->backing_dev_info->laptop_mode_wb_timer);
398 blk_sync_queue(q);
399
400 if (queue_is_mq(q))
401 blk_mq_exit_queue(q);
402
403 /*
404 * In theory, request pool of sched_tags belongs to request queue.
405 * However, the current implementation requires tag_set for freeing
406 * requests, so free the pool now.
407 *
408 * Queue has become frozen, there can't be any in-queue requests, so
409 * it is safe to free requests now.
410 */
411 mutex_lock(&q->sysfs_lock);
412 if (q->elevator)
413 blk_mq_sched_free_requests(q);
414 mutex_unlock(&q->sysfs_lock);
415
416 percpu_ref_exit(&q->q_usage_counter);
417
418 /* @q is and will stay empty, shutdown and put */
419 blk_put_queue(q);
420}
421EXPORT_SYMBOL(blk_cleanup_queue);
422
423/**
424 * blk_queue_enter() - try to increase q->q_usage_counter
425 * @q: request queue pointer
426 * @flags: BLK_MQ_REQ_NOWAIT and/or BLK_MQ_REQ_PM
427 */
428int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags)
429{
430 const bool pm = flags & BLK_MQ_REQ_PM;
431
432 while (true) {
433 bool success = false;
434
435 rcu_read_lock();
436 if (percpu_ref_tryget_live(&q->q_usage_counter)) {
437 /*
438 * The code that increments the pm_only counter is
439 * responsible for ensuring that that counter is
440 * globally visible before the queue is unfrozen.
441 */
442 if ((pm && queue_rpm_status(q) != RPM_SUSPENDED) ||
443 !blk_queue_pm_only(q)) {
444 success = true;
445 } else {
446 percpu_ref_put(&q->q_usage_counter);
447 }
448 }
449 rcu_read_unlock();
450
451 if (success)
452 return 0;
453
454 if (flags & BLK_MQ_REQ_NOWAIT)
455 return -EBUSY;
456
457 /*
458 * read pair of barrier in blk_freeze_queue_start(),
459 * we need to order reading __PERCPU_REF_DEAD flag of
460 * .q_usage_counter and reading .mq_freeze_depth or
461 * queue dying flag, otherwise the following wait may
462 * never return if the two reads are reordered.
463 */
464 smp_rmb();
465
466 wait_event(q->mq_freeze_wq,
467 (!q->mq_freeze_depth &&
468 blk_pm_resume_queue(pm, q)) ||
469 blk_queue_dying(q));
470 if (blk_queue_dying(q))
471 return -ENODEV;
472 }
473}
474
475static inline int bio_queue_enter(struct bio *bio)
476{
477 struct request_queue *q = bio->bi_bdev->bd_disk->queue;
478 bool nowait = bio->bi_opf & REQ_NOWAIT;
479 int ret;
480
481 ret = blk_queue_enter(q, nowait ? BLK_MQ_REQ_NOWAIT : 0);
482 if (unlikely(ret)) {
483 if (nowait && !blk_queue_dying(q))
484 bio_wouldblock_error(bio);
485 else
486 bio_io_error(bio);
487 }
488
489 return ret;
490}
491
492void blk_queue_exit(struct request_queue *q)
493{
494 percpu_ref_put(&q->q_usage_counter);
495}
496
497static void blk_queue_usage_counter_release(struct percpu_ref *ref)
498{
499 struct request_queue *q =
500 container_of(ref, struct request_queue, q_usage_counter);
501
502 wake_up_all(&q->mq_freeze_wq);
503}
504
505static void blk_rq_timed_out_timer(struct timer_list *t)
506{
507 struct request_queue *q = from_timer(q, t, timeout);
508
509 kblockd_schedule_work(&q->timeout_work);
510}
511
512static void blk_timeout_work(struct work_struct *work)
513{
514}
515
516struct request_queue *blk_alloc_queue(int node_id)
517{
518 struct request_queue *q;
519 int ret;
520
521 q = kmem_cache_alloc_node(blk_requestq_cachep,
522 GFP_KERNEL | __GFP_ZERO, node_id);
523 if (!q)
524 return NULL;
525
526 q->last_merge = NULL;
527
528 q->id = ida_simple_get(&blk_queue_ida, 0, 0, GFP_KERNEL);
529 if (q->id < 0)
530 goto fail_q;
531
532 ret = bioset_init(&q->bio_split, BIO_POOL_SIZE, 0, 0);
533 if (ret)
534 goto fail_id;
535
536 q->backing_dev_info = bdi_alloc(node_id);
537 if (!q->backing_dev_info)
538 goto fail_split;
539
540 q->stats = blk_alloc_queue_stats();
541 if (!q->stats)
542 goto fail_stats;
543
544 q->node = node_id;
545
546 atomic_set(&q->nr_active_requests_shared_sbitmap, 0);
547
548 timer_setup(&q->backing_dev_info->laptop_mode_wb_timer,
549 laptop_mode_timer_fn, 0);
550 timer_setup(&q->timeout, blk_rq_timed_out_timer, 0);
551 INIT_WORK(&q->timeout_work, blk_timeout_work);
552 INIT_LIST_HEAD(&q->icq_list);
553#ifdef CONFIG_BLK_CGROUP
554 INIT_LIST_HEAD(&q->blkg_list);
555#endif
556
557 kobject_init(&q->kobj, &blk_queue_ktype);
558
559 mutex_init(&q->debugfs_mutex);
560 mutex_init(&q->sysfs_lock);
561 mutex_init(&q->sysfs_dir_lock);
562 spin_lock_init(&q->queue_lock);
563
564 init_waitqueue_head(&q->mq_freeze_wq);
565 mutex_init(&q->mq_freeze_lock);
566
567 /*
568 * Init percpu_ref in atomic mode so that it's faster to shutdown.
569 * See blk_register_queue() for details.
570 */
571 if (percpu_ref_init(&q->q_usage_counter,
572 blk_queue_usage_counter_release,
573 PERCPU_REF_INIT_ATOMIC, GFP_KERNEL))
574 goto fail_bdi;
575
576 if (blkcg_init_queue(q))
577 goto fail_ref;
578
579 blk_queue_dma_alignment(q, 511);
580 blk_set_default_limits(&q->limits);
581 q->nr_requests = BLKDEV_MAX_RQ;
582
583 return q;
584
585fail_ref:
586 percpu_ref_exit(&q->q_usage_counter);
587fail_bdi:
588 blk_free_queue_stats(q->stats);
589fail_stats:
590 bdi_put(q->backing_dev_info);
591fail_split:
592 bioset_exit(&q->bio_split);
593fail_id:
594 ida_simple_remove(&blk_queue_ida, q->id);
595fail_q:
596 kmem_cache_free(blk_requestq_cachep, q);
597 return NULL;
598}
599
600/**
601 * blk_get_queue - increment the request_queue refcount
602 * @q: the request_queue structure to increment the refcount for
603 *
604 * Increment the refcount of the request_queue kobject.
605 *
606 * Context: Any context.
607 */
608bool blk_get_queue(struct request_queue *q)
609{
610 if (likely(!blk_queue_dying(q))) {
611 __blk_get_queue(q);
612 return true;
613 }
614
615 return false;
616}
617EXPORT_SYMBOL(blk_get_queue);
618
619/**
620 * blk_get_request - allocate a request
621 * @q: request queue to allocate a request for
622 * @op: operation (REQ_OP_*) and REQ_* flags, e.g. REQ_SYNC.
623 * @flags: BLK_MQ_REQ_* flags, e.g. BLK_MQ_REQ_NOWAIT.
624 */
625struct request *blk_get_request(struct request_queue *q, unsigned int op,
626 blk_mq_req_flags_t flags)
627{
628 struct request *req;
629
630 WARN_ON_ONCE(op & REQ_NOWAIT);
631 WARN_ON_ONCE(flags & ~(BLK_MQ_REQ_NOWAIT | BLK_MQ_REQ_PM));
632
633 req = blk_mq_alloc_request(q, op, flags);
634 if (!IS_ERR(req) && q->mq_ops->initialize_rq_fn)
635 q->mq_ops->initialize_rq_fn(req);
636
637 return req;
638}
639EXPORT_SYMBOL(blk_get_request);
640
641void blk_put_request(struct request *req)
642{
643 blk_mq_free_request(req);
644}
645EXPORT_SYMBOL(blk_put_request);
646
647static void handle_bad_sector(struct bio *bio, sector_t maxsector)
648{
649 char b[BDEVNAME_SIZE];
650
651 pr_info_ratelimited("attempt to access beyond end of device\n"
652 "%s: rw=%d, want=%llu, limit=%llu\n",
653 bio_devname(bio, b), bio->bi_opf,
654 bio_end_sector(bio), maxsector);
655}
656
657#ifdef CONFIG_FAIL_MAKE_REQUEST
658
659static DECLARE_FAULT_ATTR(fail_make_request);
660
661static int __init setup_fail_make_request(char *str)
662{
663 return setup_fault_attr(&fail_make_request, str);
664}
665__setup("fail_make_request=", setup_fail_make_request);
666
667static bool should_fail_request(struct block_device *part, unsigned int bytes)
668{
669 return part->bd_make_it_fail && should_fail(&fail_make_request, bytes);
670}
671
672static int __init fail_make_request_debugfs(void)
673{
674 struct dentry *dir = fault_create_debugfs_attr("fail_make_request",
675 NULL, &fail_make_request);
676
677 return PTR_ERR_OR_ZERO(dir);
678}
679
680late_initcall(fail_make_request_debugfs);
681
682#else /* CONFIG_FAIL_MAKE_REQUEST */
683
684static inline bool should_fail_request(struct block_device *part,
685 unsigned int bytes)
686{
687 return false;
688}
689
690#endif /* CONFIG_FAIL_MAKE_REQUEST */
691
692static inline bool bio_check_ro(struct bio *bio)
693{
694 if (op_is_write(bio_op(bio)) && bdev_read_only(bio->bi_bdev)) {
695 char b[BDEVNAME_SIZE];
696
697 if (op_is_flush(bio->bi_opf) && !bio_sectors(bio))
698 return false;
699
700 WARN_ONCE(1,
701 "Trying to write to read-only block-device %s (partno %d)\n",
702 bio_devname(bio, b), bio->bi_bdev->bd_partno);
703 /* Older lvm-tools actually trigger this */
704 return false;
705 }
706
707 return false;
708}
709
710static noinline int should_fail_bio(struct bio *bio)
711{
712 if (should_fail_request(bdev_whole(bio->bi_bdev), bio->bi_iter.bi_size))
713 return -EIO;
714 return 0;
715}
716ALLOW_ERROR_INJECTION(should_fail_bio, ERRNO);
717
718/*
719 * Check whether this bio extends beyond the end of the device or partition.
720 * This may well happen - the kernel calls bread() without checking the size of
721 * the device, e.g., when mounting a file system.
722 */
723static inline int bio_check_eod(struct bio *bio)
724{
725 sector_t maxsector = bdev_nr_sectors(bio->bi_bdev);
726 unsigned int nr_sectors = bio_sectors(bio);
727
728 if (nr_sectors && maxsector &&
729 (nr_sectors > maxsector ||
730 bio->bi_iter.bi_sector > maxsector - nr_sectors)) {
731 handle_bad_sector(bio, maxsector);
732 return -EIO;
733 }
734 return 0;
735}
736
737/*
738 * Remap block n of partition p to block n+start(p) of the disk.
739 */
740static int blk_partition_remap(struct bio *bio)
741{
742 struct block_device *p = bio->bi_bdev;
743
744 if (unlikely(should_fail_request(p, bio->bi_iter.bi_size)))
745 return -EIO;
746 if (bio_sectors(bio)) {
747 bio->bi_iter.bi_sector += p->bd_start_sect;
748 trace_block_bio_remap(bio, p->bd_dev,
749 bio->bi_iter.bi_sector -
750 p->bd_start_sect);
751 }
752 bio_set_flag(bio, BIO_REMAPPED);
753 return 0;
754}
755
756/*
757 * Check write append to a zoned block device.
758 */
759static inline blk_status_t blk_check_zone_append(struct request_queue *q,
760 struct bio *bio)
761{
762 sector_t pos = bio->bi_iter.bi_sector;
763 int nr_sectors = bio_sectors(bio);
764
765 /* Only applicable to zoned block devices */
766 if (!blk_queue_is_zoned(q))
767 return BLK_STS_NOTSUPP;
768
769 /* The bio sector must point to the start of a sequential zone */
770 if (pos & (blk_queue_zone_sectors(q) - 1) ||
771 !blk_queue_zone_is_seq(q, pos))
772 return BLK_STS_IOERR;
773
774 /*
775 * Not allowed to cross zone boundaries. Otherwise, the BIO will be
776 * split and could result in non-contiguous sectors being written in
777 * different zones.
778 */
779 if (nr_sectors > q->limits.chunk_sectors)
780 return BLK_STS_IOERR;
781
782 /* Make sure the BIO is small enough and will not get split */
783 if (nr_sectors > q->limits.max_zone_append_sectors)
784 return BLK_STS_IOERR;
785
786 bio->bi_opf |= REQ_NOMERGE;
787
788 return BLK_STS_OK;
789}
790
791static noinline_for_stack bool submit_bio_checks(struct bio *bio)
792{
793 struct block_device *bdev = bio->bi_bdev;
794 struct request_queue *q = bdev->bd_disk->queue;
795 blk_status_t status = BLK_STS_IOERR;
796 struct blk_plug *plug;
797
798 might_sleep();
799
800 plug = blk_mq_plug(q, bio);
801 if (plug && plug->nowait)
802 bio->bi_opf |= REQ_NOWAIT;
803
804 /*
805 * For a REQ_NOWAIT based request, return -EOPNOTSUPP
806 * if queue does not support NOWAIT.
807 */
808 if ((bio->bi_opf & REQ_NOWAIT) && !blk_queue_nowait(q))
809 goto not_supported;
810
811 if (should_fail_bio(bio))
812 goto end_io;
813 if (unlikely(bio_check_ro(bio)))
814 goto end_io;
815 if (!bio_flagged(bio, BIO_REMAPPED)) {
816 if (unlikely(bio_check_eod(bio)))
817 goto end_io;
818 if (bdev->bd_partno && unlikely(blk_partition_remap(bio)))
819 goto end_io;
820 }
821
822 /*
823 * Filter flush bio's early so that bio based drivers without flush
824 * support don't have to worry about them.
825 */
826 if (op_is_flush(bio->bi_opf) &&
827 !test_bit(QUEUE_FLAG_WC, &q->queue_flags)) {
828 bio->bi_opf &= ~(REQ_PREFLUSH | REQ_FUA);
829 if (!bio_sectors(bio)) {
830 status = BLK_STS_OK;
831 goto end_io;
832 }
833 }
834
835 if (!test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
836 bio->bi_opf &= ~REQ_HIPRI;
837
838 switch (bio_op(bio)) {
839 case REQ_OP_DISCARD:
840 if (!blk_queue_discard(q))
841 goto not_supported;
842 break;
843 case REQ_OP_SECURE_ERASE:
844 if (!blk_queue_secure_erase(q))
845 goto not_supported;
846 break;
847 case REQ_OP_WRITE_SAME:
848 if (!q->limits.max_write_same_sectors)
849 goto not_supported;
850 break;
851 case REQ_OP_ZONE_APPEND:
852 status = blk_check_zone_append(q, bio);
853 if (status != BLK_STS_OK)
854 goto end_io;
855 break;
856 case REQ_OP_ZONE_RESET:
857 case REQ_OP_ZONE_OPEN:
858 case REQ_OP_ZONE_CLOSE:
859 case REQ_OP_ZONE_FINISH:
860 if (!blk_queue_is_zoned(q))
861 goto not_supported;
862 break;
863 case REQ_OP_ZONE_RESET_ALL:
864 if (!blk_queue_is_zoned(q) || !blk_queue_zone_resetall(q))
865 goto not_supported;
866 break;
867 case REQ_OP_WRITE_ZEROES:
868 if (!q->limits.max_write_zeroes_sectors)
869 goto not_supported;
870 break;
871 default:
872 break;
873 }
874
875 /*
876 * Various block parts want %current->io_context, so allocate it up
877 * front rather than dealing with lots of pain to allocate it only
878 * where needed. This may fail and the block layer knows how to live
879 * with it.
880 */
881 if (unlikely(!current->io_context))
882 create_task_io_context(current, GFP_ATOMIC, q->node);
883
884 if (blk_throtl_bio(bio)) {
885 blkcg_bio_issue_init(bio);
886 return false;
887 }
888
889 blk_cgroup_bio_start(bio);
890 blkcg_bio_issue_init(bio);
891
892 if (!bio_flagged(bio, BIO_TRACE_COMPLETION)) {
893 trace_block_bio_queue(bio);
894 /* Now that enqueuing has been traced, we need to trace
895 * completion as well.
896 */
897 bio_set_flag(bio, BIO_TRACE_COMPLETION);
898 }
899 return true;
900
901not_supported:
902 status = BLK_STS_NOTSUPP;
903end_io:
904 bio->bi_status = status;
905 bio_endio(bio);
906 return false;
907}
908
909static blk_qc_t __submit_bio(struct bio *bio)
910{
911 struct gendisk *disk = bio->bi_bdev->bd_disk;
912 blk_qc_t ret = BLK_QC_T_NONE;
913
914 if (blk_crypto_bio_prep(&bio)) {
915 if (!disk->fops->submit_bio)
916 return blk_mq_submit_bio(bio);
917 ret = disk->fops->submit_bio(bio);
918 }
919 blk_queue_exit(disk->queue);
920 return ret;
921}
922
923/*
924 * The loop in this function may be a bit non-obvious, and so deserves some
925 * explanation:
926 *
927 * - Before entering the loop, bio->bi_next is NULL (as all callers ensure
928 * that), so we have a list with a single bio.
929 * - We pretend that we have just taken it off a longer list, so we assign
930 * bio_list to a pointer to the bio_list_on_stack, thus initialising the
931 * bio_list of new bios to be added. ->submit_bio() may indeed add some more
932 * bios through a recursive call to submit_bio_noacct. If it did, we find a
933 * non-NULL value in bio_list and re-enter the loop from the top.
934 * - In this case we really did just take the bio of the top of the list (no
935 * pretending) and so remove it from bio_list, and call into ->submit_bio()
936 * again.
937 *
938 * bio_list_on_stack[0] contains bios submitted by the current ->submit_bio.
939 * bio_list_on_stack[1] contains bios that were submitted before the current
940 * ->submit_bio_bio, but that haven't been processed yet.
941 */
942static blk_qc_t __submit_bio_noacct(struct bio *bio)
943{
944 struct bio_list bio_list_on_stack[2];
945 blk_qc_t ret = BLK_QC_T_NONE;
946
947 BUG_ON(bio->bi_next);
948
949 bio_list_init(&bio_list_on_stack[0]);
950 current->bio_list = bio_list_on_stack;
951
952 do {
953 struct request_queue *q = bio->bi_bdev->bd_disk->queue;
954 struct bio_list lower, same;
955
956 if (unlikely(bio_queue_enter(bio) != 0))
957 continue;
958
959 /*
960 * Create a fresh bio_list for all subordinate requests.
961 */
962 bio_list_on_stack[1] = bio_list_on_stack[0];
963 bio_list_init(&bio_list_on_stack[0]);
964
965 ret = __submit_bio(bio);
966
967 /*
968 * Sort new bios into those for a lower level and those for the
969 * same level.
970 */
971 bio_list_init(&lower);
972 bio_list_init(&same);
973 while ((bio = bio_list_pop(&bio_list_on_stack[0])) != NULL)
974 if (q == bio->bi_bdev->bd_disk->queue)
975 bio_list_add(&same, bio);
976 else
977 bio_list_add(&lower, bio);
978
979 /*
980 * Now assemble so we handle the lowest level first.
981 */
982 bio_list_merge(&bio_list_on_stack[0], &lower);
983 bio_list_merge(&bio_list_on_stack[0], &same);
984 bio_list_merge(&bio_list_on_stack[0], &bio_list_on_stack[1]);
985 } while ((bio = bio_list_pop(&bio_list_on_stack[0])));
986
987 current->bio_list = NULL;
988 return ret;
989}
990
991static blk_qc_t __submit_bio_noacct_mq(struct bio *bio)
992{
993 struct bio_list bio_list[2] = { };
994 blk_qc_t ret = BLK_QC_T_NONE;
995
996 current->bio_list = bio_list;
997
998 do {
999 struct gendisk *disk = bio->bi_bdev->bd_disk;
1000
1001 if (unlikely(bio_queue_enter(bio) != 0))
1002 continue;
1003
1004 if (!blk_crypto_bio_prep(&bio)) {
1005 blk_queue_exit(disk->queue);
1006 ret = BLK_QC_T_NONE;
1007 continue;
1008 }
1009
1010 ret = blk_mq_submit_bio(bio);
1011 } while ((bio = bio_list_pop(&bio_list[0])));
1012
1013 current->bio_list = NULL;
1014 return ret;
1015}
1016
1017/**
1018 * submit_bio_noacct - re-submit a bio to the block device layer for I/O
1019 * @bio: The bio describing the location in memory and on the device.
1020 *
1021 * This is a version of submit_bio() that shall only be used for I/O that is
1022 * resubmitted to lower level drivers by stacking block drivers. All file
1023 * systems and other upper level users of the block layer should use
1024 * submit_bio() instead.
1025 */
1026blk_qc_t submit_bio_noacct(struct bio *bio)
1027{
1028 if (!submit_bio_checks(bio))
1029 return BLK_QC_T_NONE;
1030
1031 /*
1032 * We only want one ->submit_bio to be active at a time, else stack
1033 * usage with stacked devices could be a problem. Use current->bio_list
1034 * to collect a list of requests submited by a ->submit_bio method while
1035 * it is active, and then process them after it returned.
1036 */
1037 if (current->bio_list) {
1038 bio_list_add(¤t->bio_list[0], bio);
1039 return BLK_QC_T_NONE;
1040 }
1041
1042 if (!bio->bi_bdev->bd_disk->fops->submit_bio)
1043 return __submit_bio_noacct_mq(bio);
1044 return __submit_bio_noacct(bio);
1045}
1046EXPORT_SYMBOL(submit_bio_noacct);
1047
1048/**
1049 * submit_bio - submit a bio to the block device layer for I/O
1050 * @bio: The &struct bio which describes the I/O
1051 *
1052 * submit_bio() is used to submit I/O requests to block devices. It is passed a
1053 * fully set up &struct bio that describes the I/O that needs to be done. The
1054 * bio will be send to the device described by the bi_bdev field.
1055 *
1056 * The success/failure status of the request, along with notification of
1057 * completion, is delivered asynchronously through the ->bi_end_io() callback
1058 * in @bio. The bio must NOT be touched by thecaller until ->bi_end_io() has
1059 * been called.
1060 */
1061blk_qc_t submit_bio(struct bio *bio)
1062{
1063 if (blkcg_punt_bio_submit(bio))
1064 return BLK_QC_T_NONE;
1065
1066 /*
1067 * If it's a regular read/write or a barrier with data attached,
1068 * go through the normal accounting stuff before submission.
1069 */
1070 if (bio_has_data(bio)) {
1071 unsigned int count;
1072
1073 if (unlikely(bio_op(bio) == REQ_OP_WRITE_SAME))
1074 count = queue_logical_block_size(
1075 bio->bi_bdev->bd_disk->queue) >> 9;
1076 else
1077 count = bio_sectors(bio);
1078
1079 if (op_is_write(bio_op(bio))) {
1080 count_vm_events(PGPGOUT, count);
1081 } else {
1082 task_io_account_read(bio->bi_iter.bi_size);
1083 count_vm_events(PGPGIN, count);
1084 }
1085 }
1086
1087 /*
1088 * If we're reading data that is part of the userspace workingset, count
1089 * submission time as memory stall. When the device is congested, or
1090 * the submitting cgroup IO-throttled, submission can be a significant
1091 * part of overall IO time.
1092 */
1093 if (unlikely(bio_op(bio) == REQ_OP_READ &&
1094 bio_flagged(bio, BIO_WORKINGSET))) {
1095 unsigned long pflags;
1096 blk_qc_t ret;
1097
1098 psi_memstall_enter(&pflags);
1099 ret = submit_bio_noacct(bio);
1100 psi_memstall_leave(&pflags);
1101
1102 return ret;
1103 }
1104
1105 return submit_bio_noacct(bio);
1106}
1107EXPORT_SYMBOL(submit_bio);
1108
1109/**
1110 * blk_cloned_rq_check_limits - Helper function to check a cloned request
1111 * for the new queue limits
1112 * @q: the queue
1113 * @rq: the request being checked
1114 *
1115 * Description:
1116 * @rq may have been made based on weaker limitations of upper-level queues
1117 * in request stacking drivers, and it may violate the limitation of @q.
1118 * Since the block layer and the underlying device driver trust @rq
1119 * after it is inserted to @q, it should be checked against @q before
1120 * the insertion using this generic function.
1121 *
1122 * Request stacking drivers like request-based dm may change the queue
1123 * limits when retrying requests on other queues. Those requests need
1124 * to be checked against the new queue limits again during dispatch.
1125 */
1126static blk_status_t blk_cloned_rq_check_limits(struct request_queue *q,
1127 struct request *rq)
1128{
1129 unsigned int max_sectors = blk_queue_get_max_sectors(q, req_op(rq));
1130
1131 if (blk_rq_sectors(rq) > max_sectors) {
1132 /*
1133 * SCSI device does not have a good way to return if
1134 * Write Same/Zero is actually supported. If a device rejects
1135 * a non-read/write command (discard, write same,etc.) the
1136 * low-level device driver will set the relevant queue limit to
1137 * 0 to prevent blk-lib from issuing more of the offending
1138 * operations. Commands queued prior to the queue limit being
1139 * reset need to be completed with BLK_STS_NOTSUPP to avoid I/O
1140 * errors being propagated to upper layers.
1141 */
1142 if (max_sectors == 0)
1143 return BLK_STS_NOTSUPP;
1144
1145 printk(KERN_ERR "%s: over max size limit. (%u > %u)\n",
1146 __func__, blk_rq_sectors(rq), max_sectors);
1147 return BLK_STS_IOERR;
1148 }
1149
1150 /*
1151 * The queue settings related to segment counting may differ from the
1152 * original queue.
1153 */
1154 rq->nr_phys_segments = blk_recalc_rq_segments(rq);
1155 if (rq->nr_phys_segments > queue_max_segments(q)) {
1156 printk(KERN_ERR "%s: over max segments limit. (%hu > %hu)\n",
1157 __func__, rq->nr_phys_segments, queue_max_segments(q));
1158 return BLK_STS_IOERR;
1159 }
1160
1161 return BLK_STS_OK;
1162}
1163
1164/**
1165 * blk_insert_cloned_request - Helper for stacking drivers to submit a request
1166 * @q: the queue to submit the request
1167 * @rq: the request being queued
1168 */
1169blk_status_t blk_insert_cloned_request(struct request_queue *q, struct request *rq)
1170{
1171 blk_status_t ret;
1172
1173 ret = blk_cloned_rq_check_limits(q, rq);
1174 if (ret != BLK_STS_OK)
1175 return ret;
1176
1177 if (rq->rq_disk &&
1178 should_fail_request(rq->rq_disk->part0, blk_rq_bytes(rq)))
1179 return BLK_STS_IOERR;
1180
1181 if (blk_crypto_insert_cloned_request(rq))
1182 return BLK_STS_IOERR;
1183
1184 if (blk_queue_io_stat(q))
1185 blk_account_io_start(rq);
1186
1187 /*
1188 * Since we have a scheduler attached on the top device,
1189 * bypass a potential scheduler on the bottom device for
1190 * insert.
1191 */
1192 return blk_mq_request_issue_directly(rq, true);
1193}
1194EXPORT_SYMBOL_GPL(blk_insert_cloned_request);
1195
1196/**
1197 * blk_rq_err_bytes - determine number of bytes till the next failure boundary
1198 * @rq: request to examine
1199 *
1200 * Description:
1201 * A request could be merge of IOs which require different failure
1202 * handling. This function determines the number of bytes which
1203 * can be failed from the beginning of the request without
1204 * crossing into area which need to be retried further.
1205 *
1206 * Return:
1207 * The number of bytes to fail.
1208 */
1209unsigned int blk_rq_err_bytes(const struct request *rq)
1210{
1211 unsigned int ff = rq->cmd_flags & REQ_FAILFAST_MASK;
1212 unsigned int bytes = 0;
1213 struct bio *bio;
1214
1215 if (!(rq->rq_flags & RQF_MIXED_MERGE))
1216 return blk_rq_bytes(rq);
1217
1218 /*
1219 * Currently the only 'mixing' which can happen is between
1220 * different fastfail types. We can safely fail portions
1221 * which have all the failfast bits that the first one has -
1222 * the ones which are at least as eager to fail as the first
1223 * one.
1224 */
1225 for (bio = rq->bio; bio; bio = bio->bi_next) {
1226 if ((bio->bi_opf & ff) != ff)
1227 break;
1228 bytes += bio->bi_iter.bi_size;
1229 }
1230
1231 /* this could lead to infinite loop */
1232 BUG_ON(blk_rq_bytes(rq) && !bytes);
1233 return bytes;
1234}
1235EXPORT_SYMBOL_GPL(blk_rq_err_bytes);
1236
1237static void update_io_ticks(struct block_device *part, unsigned long now,
1238 bool end)
1239{
1240 unsigned long stamp;
1241again:
1242 stamp = READ_ONCE(part->bd_stamp);
1243 if (unlikely(time_after(now, stamp))) {
1244 if (likely(cmpxchg(&part->bd_stamp, stamp, now) == stamp))
1245 __part_stat_add(part, io_ticks, end ? now - stamp : 1);
1246 }
1247 if (part->bd_partno) {
1248 part = bdev_whole(part);
1249 goto again;
1250 }
1251}
1252
1253static void blk_account_io_completion(struct request *req, unsigned int bytes)
1254{
1255 if (req->part && blk_do_io_stat(req)) {
1256 const int sgrp = op_stat_group(req_op(req));
1257
1258 part_stat_lock();
1259 part_stat_add(req->part, sectors[sgrp], bytes >> 9);
1260 part_stat_unlock();
1261 }
1262}
1263
1264void blk_account_io_done(struct request *req, u64 now)
1265{
1266 /*
1267 * Account IO completion. flush_rq isn't accounted as a
1268 * normal IO on queueing nor completion. Accounting the
1269 * containing request is enough.
1270 */
1271 if (req->part && blk_do_io_stat(req) &&
1272 !(req->rq_flags & RQF_FLUSH_SEQ)) {
1273 const int sgrp = op_stat_group(req_op(req));
1274
1275 part_stat_lock();
1276 update_io_ticks(req->part, jiffies, true);
1277 part_stat_inc(req->part, ios[sgrp]);
1278 part_stat_add(req->part, nsecs[sgrp], now - req->start_time_ns);
1279 part_stat_unlock();
1280 }
1281}
1282
1283void blk_account_io_start(struct request *rq)
1284{
1285 if (!blk_do_io_stat(rq))
1286 return;
1287
1288 /* passthrough requests can hold bios that do not have ->bi_bdev set */
1289 if (rq->bio && rq->bio->bi_bdev)
1290 rq->part = rq->bio->bi_bdev;
1291 else
1292 rq->part = rq->rq_disk->part0;
1293
1294 part_stat_lock();
1295 update_io_ticks(rq->part, jiffies, false);
1296 part_stat_unlock();
1297}
1298
1299static unsigned long __part_start_io_acct(struct block_device *part,
1300 unsigned int sectors, unsigned int op)
1301{
1302 const int sgrp = op_stat_group(op);
1303 unsigned long now = READ_ONCE(jiffies);
1304
1305 part_stat_lock();
1306 update_io_ticks(part, now, false);
1307 part_stat_inc(part, ios[sgrp]);
1308 part_stat_add(part, sectors[sgrp], sectors);
1309 part_stat_local_inc(part, in_flight[op_is_write(op)]);
1310 part_stat_unlock();
1311
1312 return now;
1313}
1314
1315/**
1316 * bio_start_io_acct - start I/O accounting for bio based drivers
1317 * @bio: bio to start account for
1318 *
1319 * Returns the start time that should be passed back to bio_end_io_acct().
1320 */
1321unsigned long bio_start_io_acct(struct bio *bio)
1322{
1323 return __part_start_io_acct(bio->bi_bdev, bio_sectors(bio), bio_op(bio));
1324}
1325EXPORT_SYMBOL_GPL(bio_start_io_acct);
1326
1327unsigned long disk_start_io_acct(struct gendisk *disk, unsigned int sectors,
1328 unsigned int op)
1329{
1330 return __part_start_io_acct(disk->part0, sectors, op);
1331}
1332EXPORT_SYMBOL(disk_start_io_acct);
1333
1334static void __part_end_io_acct(struct block_device *part, unsigned int op,
1335 unsigned long start_time)
1336{
1337 const int sgrp = op_stat_group(op);
1338 unsigned long now = READ_ONCE(jiffies);
1339 unsigned long duration = now - start_time;
1340
1341 part_stat_lock();
1342 update_io_ticks(part, now, true);
1343 part_stat_add(part, nsecs[sgrp], jiffies_to_nsecs(duration));
1344 part_stat_local_dec(part, in_flight[op_is_write(op)]);
1345 part_stat_unlock();
1346}
1347
1348void bio_end_io_acct_remapped(struct bio *bio, unsigned long start_time,
1349 struct block_device *orig_bdev)
1350{
1351 __part_end_io_acct(orig_bdev, bio_op(bio), start_time);
1352}
1353EXPORT_SYMBOL_GPL(bio_end_io_acct_remapped);
1354
1355void disk_end_io_acct(struct gendisk *disk, unsigned int op,
1356 unsigned long start_time)
1357{
1358 __part_end_io_acct(disk->part0, op, start_time);
1359}
1360EXPORT_SYMBOL(disk_end_io_acct);
1361
1362/*
1363 * Steal bios from a request and add them to a bio list.
1364 * The request must not have been partially completed before.
1365 */
1366void blk_steal_bios(struct bio_list *list, struct request *rq)
1367{
1368 if (rq->bio) {
1369 if (list->tail)
1370 list->tail->bi_next = rq->bio;
1371 else
1372 list->head = rq->bio;
1373 list->tail = rq->biotail;
1374
1375 rq->bio = NULL;
1376 rq->biotail = NULL;
1377 }
1378
1379 rq->__data_len = 0;
1380}
1381EXPORT_SYMBOL_GPL(blk_steal_bios);
1382
1383/**
1384 * blk_update_request - Complete multiple bytes without completing the request
1385 * @req: the request being processed
1386 * @error: block status code
1387 * @nr_bytes: number of bytes to complete for @req
1388 *
1389 * Description:
1390 * Ends I/O on a number of bytes attached to @req, but doesn't complete
1391 * the request structure even if @req doesn't have leftover.
1392 * If @req has leftover, sets it up for the next range of segments.
1393 *
1394 * Passing the result of blk_rq_bytes() as @nr_bytes guarantees
1395 * %false return from this function.
1396 *
1397 * Note:
1398 * The RQF_SPECIAL_PAYLOAD flag is ignored on purpose in this function
1399 * except in the consistency check at the end of this function.
1400 *
1401 * Return:
1402 * %false - this request doesn't have any more data
1403 * %true - this request has more data
1404 **/
1405bool blk_update_request(struct request *req, blk_status_t error,
1406 unsigned int nr_bytes)
1407{
1408 int total_bytes;
1409
1410 trace_block_rq_complete(req, blk_status_to_errno(error), nr_bytes);
1411
1412 if (!req->bio)
1413 return false;
1414
1415#ifdef CONFIG_BLK_DEV_INTEGRITY
1416 if (blk_integrity_rq(req) && req_op(req) == REQ_OP_READ &&
1417 error == BLK_STS_OK)
1418 req->q->integrity.profile->complete_fn(req, nr_bytes);
1419#endif
1420
1421 if (unlikely(error && !blk_rq_is_passthrough(req) &&
1422 !(req->rq_flags & RQF_QUIET)))
1423 print_req_error(req, error, __func__);
1424
1425 blk_account_io_completion(req, nr_bytes);
1426
1427 total_bytes = 0;
1428 while (req->bio) {
1429 struct bio *bio = req->bio;
1430 unsigned bio_bytes = min(bio->bi_iter.bi_size, nr_bytes);
1431
1432 if (bio_bytes == bio->bi_iter.bi_size)
1433 req->bio = bio->bi_next;
1434
1435 /* Completion has already been traced */
1436 bio_clear_flag(bio, BIO_TRACE_COMPLETION);
1437 req_bio_endio(req, bio, bio_bytes, error);
1438
1439 total_bytes += bio_bytes;
1440 nr_bytes -= bio_bytes;
1441
1442 if (!nr_bytes)
1443 break;
1444 }
1445
1446 /*
1447 * completely done
1448 */
1449 if (!req->bio) {
1450 /*
1451 * Reset counters so that the request stacking driver
1452 * can find how many bytes remain in the request
1453 * later.
1454 */
1455 req->__data_len = 0;
1456 return false;
1457 }
1458
1459 req->__data_len -= total_bytes;
1460
1461 /* update sector only for requests with clear definition of sector */
1462 if (!blk_rq_is_passthrough(req))
1463 req->__sector += total_bytes >> 9;
1464
1465 /* mixed attributes always follow the first bio */
1466 if (req->rq_flags & RQF_MIXED_MERGE) {
1467 req->cmd_flags &= ~REQ_FAILFAST_MASK;
1468 req->cmd_flags |= req->bio->bi_opf & REQ_FAILFAST_MASK;
1469 }
1470
1471 if (!(req->rq_flags & RQF_SPECIAL_PAYLOAD)) {
1472 /*
1473 * If total number of sectors is less than the first segment
1474 * size, something has gone terribly wrong.
1475 */
1476 if (blk_rq_bytes(req) < blk_rq_cur_bytes(req)) {
1477 blk_dump_rq_flags(req, "request botched");
1478 req->__data_len = blk_rq_cur_bytes(req);
1479 }
1480
1481 /* recalculate the number of segments */
1482 req->nr_phys_segments = blk_recalc_rq_segments(req);
1483 }
1484
1485 return true;
1486}
1487EXPORT_SYMBOL_GPL(blk_update_request);
1488
1489#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
1490/**
1491 * rq_flush_dcache_pages - Helper function to flush all pages in a request
1492 * @rq: the request to be flushed
1493 *
1494 * Description:
1495 * Flush all pages in @rq.
1496 */
1497void rq_flush_dcache_pages(struct request *rq)
1498{
1499 struct req_iterator iter;
1500 struct bio_vec bvec;
1501
1502 rq_for_each_segment(bvec, rq, iter)
1503 flush_dcache_page(bvec.bv_page);
1504}
1505EXPORT_SYMBOL_GPL(rq_flush_dcache_pages);
1506#endif
1507
1508/**
1509 * blk_lld_busy - Check if underlying low-level drivers of a device are busy
1510 * @q : the queue of the device being checked
1511 *
1512 * Description:
1513 * Check if underlying low-level drivers of a device are busy.
1514 * If the drivers want to export their busy state, they must set own
1515 * exporting function using blk_queue_lld_busy() first.
1516 *
1517 * Basically, this function is used only by request stacking drivers
1518 * to stop dispatching requests to underlying devices when underlying
1519 * devices are busy. This behavior helps more I/O merging on the queue
1520 * of the request stacking driver and prevents I/O throughput regression
1521 * on burst I/O load.
1522 *
1523 * Return:
1524 * 0 - Not busy (The request stacking driver should dispatch request)
1525 * 1 - Busy (The request stacking driver should stop dispatching request)
1526 */
1527int blk_lld_busy(struct request_queue *q)
1528{
1529 if (queue_is_mq(q) && q->mq_ops->busy)
1530 return q->mq_ops->busy(q);
1531
1532 return 0;
1533}
1534EXPORT_SYMBOL_GPL(blk_lld_busy);
1535
1536/**
1537 * blk_rq_unprep_clone - Helper function to free all bios in a cloned request
1538 * @rq: the clone request to be cleaned up
1539 *
1540 * Description:
1541 * Free all bios in @rq for a cloned request.
1542 */
1543void blk_rq_unprep_clone(struct request *rq)
1544{
1545 struct bio *bio;
1546
1547 while ((bio = rq->bio) != NULL) {
1548 rq->bio = bio->bi_next;
1549
1550 bio_put(bio);
1551 }
1552}
1553EXPORT_SYMBOL_GPL(blk_rq_unprep_clone);
1554
1555/**
1556 * blk_rq_prep_clone - Helper function to setup clone request
1557 * @rq: the request to be setup
1558 * @rq_src: original request to be cloned
1559 * @bs: bio_set that bios for clone are allocated from
1560 * @gfp_mask: memory allocation mask for bio
1561 * @bio_ctr: setup function to be called for each clone bio.
1562 * Returns %0 for success, non %0 for failure.
1563 * @data: private data to be passed to @bio_ctr
1564 *
1565 * Description:
1566 * Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq.
1567 * Also, pages which the original bios are pointing to are not copied
1568 * and the cloned bios just point same pages.
1569 * So cloned bios must be completed before original bios, which means
1570 * the caller must complete @rq before @rq_src.
1571 */
1572int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
1573 struct bio_set *bs, gfp_t gfp_mask,
1574 int (*bio_ctr)(struct bio *, struct bio *, void *),
1575 void *data)
1576{
1577 struct bio *bio, *bio_src;
1578
1579 if (!bs)
1580 bs = &fs_bio_set;
1581
1582 __rq_for_each_bio(bio_src, rq_src) {
1583 bio = bio_clone_fast(bio_src, gfp_mask, bs);
1584 if (!bio)
1585 goto free_and_out;
1586
1587 if (bio_ctr && bio_ctr(bio, bio_src, data))
1588 goto free_and_out;
1589
1590 if (rq->bio) {
1591 rq->biotail->bi_next = bio;
1592 rq->biotail = bio;
1593 } else {
1594 rq->bio = rq->biotail = bio;
1595 }
1596 bio = NULL;
1597 }
1598
1599 /* Copy attributes of the original request to the clone request. */
1600 rq->__sector = blk_rq_pos(rq_src);
1601 rq->__data_len = blk_rq_bytes(rq_src);
1602 if (rq_src->rq_flags & RQF_SPECIAL_PAYLOAD) {
1603 rq->rq_flags |= RQF_SPECIAL_PAYLOAD;
1604 rq->special_vec = rq_src->special_vec;
1605 }
1606 rq->nr_phys_segments = rq_src->nr_phys_segments;
1607 rq->ioprio = rq_src->ioprio;
1608
1609 if (rq->bio && blk_crypto_rq_bio_prep(rq, rq->bio, gfp_mask) < 0)
1610 goto free_and_out;
1611
1612 return 0;
1613
1614free_and_out:
1615 if (bio)
1616 bio_put(bio);
1617 blk_rq_unprep_clone(rq);
1618
1619 return -ENOMEM;
1620}
1621EXPORT_SYMBOL_GPL(blk_rq_prep_clone);
1622
1623int kblockd_schedule_work(struct work_struct *work)
1624{
1625 return queue_work(kblockd_workqueue, work);
1626}
1627EXPORT_SYMBOL(kblockd_schedule_work);
1628
1629int kblockd_mod_delayed_work_on(int cpu, struct delayed_work *dwork,
1630 unsigned long delay)
1631{
1632 return mod_delayed_work_on(cpu, kblockd_workqueue, dwork, delay);
1633}
1634EXPORT_SYMBOL(kblockd_mod_delayed_work_on);
1635
1636/**
1637 * blk_start_plug - initialize blk_plug and track it inside the task_struct
1638 * @plug: The &struct blk_plug that needs to be initialized
1639 *
1640 * Description:
1641 * blk_start_plug() indicates to the block layer an intent by the caller
1642 * to submit multiple I/O requests in a batch. The block layer may use
1643 * this hint to defer submitting I/Os from the caller until blk_finish_plug()
1644 * is called. However, the block layer may choose to submit requests
1645 * before a call to blk_finish_plug() if the number of queued I/Os
1646 * exceeds %BLK_MAX_REQUEST_COUNT, or if the size of the I/O is larger than
1647 * %BLK_PLUG_FLUSH_SIZE. The queued I/Os may also be submitted early if
1648 * the task schedules (see below).
1649 *
1650 * Tracking blk_plug inside the task_struct will help with auto-flushing the
1651 * pending I/O should the task end up blocking between blk_start_plug() and
1652 * blk_finish_plug(). This is important from a performance perspective, but
1653 * also ensures that we don't deadlock. For instance, if the task is blocking
1654 * for a memory allocation, memory reclaim could end up wanting to free a
1655 * page belonging to that request that is currently residing in our private
1656 * plug. By flushing the pending I/O when the process goes to sleep, we avoid
1657 * this kind of deadlock.
1658 */
1659void blk_start_plug(struct blk_plug *plug)
1660{
1661 struct task_struct *tsk = current;
1662
1663 /*
1664 * If this is a nested plug, don't actually assign it.
1665 */
1666 if (tsk->plug)
1667 return;
1668
1669 INIT_LIST_HEAD(&plug->mq_list);
1670 INIT_LIST_HEAD(&plug->cb_list);
1671 plug->rq_count = 0;
1672 plug->multiple_queues = false;
1673 plug->nowait = false;
1674
1675 /*
1676 * Store ordering should not be needed here, since a potential
1677 * preempt will imply a full memory barrier
1678 */
1679 tsk->plug = plug;
1680}
1681EXPORT_SYMBOL(blk_start_plug);
1682
1683static void flush_plug_callbacks(struct blk_plug *plug, bool from_schedule)
1684{
1685 LIST_HEAD(callbacks);
1686
1687 while (!list_empty(&plug->cb_list)) {
1688 list_splice_init(&plug->cb_list, &callbacks);
1689
1690 while (!list_empty(&callbacks)) {
1691 struct blk_plug_cb *cb = list_first_entry(&callbacks,
1692 struct blk_plug_cb,
1693 list);
1694 list_del(&cb->list);
1695 cb->callback(cb, from_schedule);
1696 }
1697 }
1698}
1699
1700struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug, void *data,
1701 int size)
1702{
1703 struct blk_plug *plug = current->plug;
1704 struct blk_plug_cb *cb;
1705
1706 if (!plug)
1707 return NULL;
1708
1709 list_for_each_entry(cb, &plug->cb_list, list)
1710 if (cb->callback == unplug && cb->data == data)
1711 return cb;
1712
1713 /* Not currently on the callback list */
1714 BUG_ON(size < sizeof(*cb));
1715 cb = kzalloc(size, GFP_ATOMIC);
1716 if (cb) {
1717 cb->data = data;
1718 cb->callback = unplug;
1719 list_add(&cb->list, &plug->cb_list);
1720 }
1721 return cb;
1722}
1723EXPORT_SYMBOL(blk_check_plugged);
1724
1725void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule)
1726{
1727 flush_plug_callbacks(plug, from_schedule);
1728
1729 if (!list_empty(&plug->mq_list))
1730 blk_mq_flush_plug_list(plug, from_schedule);
1731}
1732
1733/**
1734 * blk_finish_plug - mark the end of a batch of submitted I/O
1735 * @plug: The &struct blk_plug passed to blk_start_plug()
1736 *
1737 * Description:
1738 * Indicate that a batch of I/O submissions is complete. This function
1739 * must be paired with an initial call to blk_start_plug(). The intent
1740 * is to allow the block layer to optimize I/O submission. See the
1741 * documentation for blk_start_plug() for more information.
1742 */
1743void blk_finish_plug(struct blk_plug *plug)
1744{
1745 if (plug != current->plug)
1746 return;
1747 blk_flush_plug_list(plug, false);
1748
1749 current->plug = NULL;
1750}
1751EXPORT_SYMBOL(blk_finish_plug);
1752
1753void blk_io_schedule(void)
1754{
1755 /* Prevent hang_check timer from firing at us during very long I/O */
1756 unsigned long timeout = sysctl_hung_task_timeout_secs * HZ / 2;
1757
1758 if (timeout)
1759 io_schedule_timeout(timeout);
1760 else
1761 io_schedule();
1762}
1763EXPORT_SYMBOL_GPL(blk_io_schedule);
1764
1765int __init blk_dev_init(void)
1766{
1767 BUILD_BUG_ON(REQ_OP_LAST >= (1 << REQ_OP_BITS));
1768 BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 *
1769 sizeof_field(struct request, cmd_flags));
1770 BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 *
1771 sizeof_field(struct bio, bi_opf));
1772
1773 /* used for unplugging and affects IO latency/throughput - HIGHPRI */
1774 kblockd_workqueue = alloc_workqueue("kblockd",
1775 WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
1776 if (!kblockd_workqueue)
1777 panic("Failed to create kblockd\n");
1778
1779 blk_requestq_cachep = kmem_cache_create("request_queue",
1780 sizeof(struct request_queue), 0, SLAB_PANIC, NULL);
1781
1782 blk_debugfs_root = debugfs_create_dir("block", NULL);
1783
1784 return 0;
1785}