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 | #include "blk-ioprio.h" |
53 | |
54 | struct dentry *blk_debugfs_root; |
55 | |
56 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap); |
57 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap); |
58 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete); |
59 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_split); |
60 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug); |
61 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_insert); |
62 | |
63 | static DEFINE_IDA(blk_queue_ida); |
64 | |
65 | /* |
66 | * For queue allocation |
67 | */ |
68 | static struct kmem_cache *blk_requestq_cachep; |
69 | |
70 | /* |
71 | * Controlling structure to kblockd |
72 | */ |
73 | static struct workqueue_struct *kblockd_workqueue; |
74 | |
75 | /** |
76 | * blk_queue_flag_set - atomically set a queue flag |
77 | * @flag: flag to be set |
78 | * @q: request queue |
79 | */ |
80 | void blk_queue_flag_set(unsigned int flag, struct request_queue *q) |
81 | { |
82 | set_bit(nr: flag, addr: &q->queue_flags); |
83 | } |
84 | EXPORT_SYMBOL(blk_queue_flag_set); |
85 | |
86 | /** |
87 | * blk_queue_flag_clear - atomically clear a queue flag |
88 | * @flag: flag to be cleared |
89 | * @q: request queue |
90 | */ |
91 | void blk_queue_flag_clear(unsigned int flag, struct request_queue *q) |
92 | { |
93 | clear_bit(nr: flag, addr: &q->queue_flags); |
94 | } |
95 | EXPORT_SYMBOL(blk_queue_flag_clear); |
96 | |
97 | /** |
98 | * blk_queue_flag_test_and_set - atomically test and set a queue flag |
99 | * @flag: flag to be set |
100 | * @q: request queue |
101 | * |
102 | * Returns the previous value of @flag - 0 if the flag was not set and 1 if |
103 | * the flag was already set. |
104 | */ |
105 | bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q) |
106 | { |
107 | return test_and_set_bit(nr: flag, addr: &q->queue_flags); |
108 | } |
109 | EXPORT_SYMBOL_GPL(blk_queue_flag_test_and_set); |
110 | |
111 | #define REQ_OP_NAME(name) [REQ_OP_##name] = #name |
112 | static const char *const blk_op_name[] = { |
113 | REQ_OP_NAME(READ), |
114 | REQ_OP_NAME(WRITE), |
115 | REQ_OP_NAME(FLUSH), |
116 | REQ_OP_NAME(DISCARD), |
117 | REQ_OP_NAME(SECURE_ERASE), |
118 | REQ_OP_NAME(ZONE_RESET), |
119 | REQ_OP_NAME(ZONE_RESET_ALL), |
120 | REQ_OP_NAME(ZONE_OPEN), |
121 | REQ_OP_NAME(ZONE_CLOSE), |
122 | REQ_OP_NAME(ZONE_FINISH), |
123 | REQ_OP_NAME(ZONE_APPEND), |
124 | REQ_OP_NAME(WRITE_ZEROES), |
125 | REQ_OP_NAME(DRV_IN), |
126 | REQ_OP_NAME(DRV_OUT), |
127 | }; |
128 | #undef REQ_OP_NAME |
129 | |
130 | /** |
131 | * blk_op_str - Return string XXX in the REQ_OP_XXX. |
132 | * @op: REQ_OP_XXX. |
133 | * |
134 | * Description: Centralize block layer function to convert REQ_OP_XXX into |
135 | * string format. Useful in the debugging and tracing bio or request. For |
136 | * invalid REQ_OP_XXX it returns string "UNKNOWN". |
137 | */ |
138 | inline const char *blk_op_str(enum req_op op) |
139 | { |
140 | const char *op_str = "UNKNOWN" ; |
141 | |
142 | if (op < ARRAY_SIZE(blk_op_name) && blk_op_name[op]) |
143 | op_str = blk_op_name[op]; |
144 | |
145 | return op_str; |
146 | } |
147 | EXPORT_SYMBOL_GPL(blk_op_str); |
148 | |
149 | static const struct { |
150 | int errno; |
151 | const char *name; |
152 | } blk_errors[] = { |
153 | [BLK_STS_OK] = { .errno: 0, .name: "" }, |
154 | [BLK_STS_NOTSUPP] = { -EOPNOTSUPP, "operation not supported" }, |
155 | [BLK_STS_TIMEOUT] = { -ETIMEDOUT, "timeout" }, |
156 | [BLK_STS_NOSPC] = { -ENOSPC, "critical space allocation" }, |
157 | [BLK_STS_TRANSPORT] = { -ENOLINK, "recoverable transport" }, |
158 | [BLK_STS_TARGET] = { -EREMOTEIO, "critical target" }, |
159 | [BLK_STS_RESV_CONFLICT] = { -EBADE, "reservation conflict" }, |
160 | [BLK_STS_MEDIUM] = { -ENODATA, "critical medium" }, |
161 | [BLK_STS_PROTECTION] = { -EILSEQ, "protection" }, |
162 | [BLK_STS_RESOURCE] = { -ENOMEM, "kernel resource" }, |
163 | [BLK_STS_DEV_RESOURCE] = { -EBUSY, "device resource" }, |
164 | [BLK_STS_AGAIN] = { -EAGAIN, "nonblocking retry" }, |
165 | [BLK_STS_OFFLINE] = { -ENODEV, "device offline" }, |
166 | |
167 | /* device mapper special case, should not leak out: */ |
168 | [BLK_STS_DM_REQUEUE] = { -EREMCHG, "dm internal retry" }, |
169 | |
170 | /* zone device specific errors */ |
171 | [BLK_STS_ZONE_OPEN_RESOURCE] = { -ETOOMANYREFS, "open zones exceeded" }, |
172 | [BLK_STS_ZONE_ACTIVE_RESOURCE] = { -EOVERFLOW, "active zones exceeded" }, |
173 | |
174 | /* Command duration limit device-side timeout */ |
175 | [BLK_STS_DURATION_LIMIT] = { -ETIME, "duration limit exceeded" }, |
176 | |
177 | /* everything else not covered above: */ |
178 | [BLK_STS_IOERR] = { -EIO, "I/O" }, |
179 | }; |
180 | |
181 | blk_status_t errno_to_blk_status(int errno) |
182 | { |
183 | int i; |
184 | |
185 | for (i = 0; i < ARRAY_SIZE(blk_errors); i++) { |
186 | if (blk_errors[i].errno == errno) |
187 | return (__force blk_status_t)i; |
188 | } |
189 | |
190 | return BLK_STS_IOERR; |
191 | } |
192 | EXPORT_SYMBOL_GPL(errno_to_blk_status); |
193 | |
194 | int blk_status_to_errno(blk_status_t status) |
195 | { |
196 | int idx = (__force int)status; |
197 | |
198 | if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors))) |
199 | return -EIO; |
200 | return blk_errors[idx].errno; |
201 | } |
202 | EXPORT_SYMBOL_GPL(blk_status_to_errno); |
203 | |
204 | const char *blk_status_to_str(blk_status_t status) |
205 | { |
206 | int idx = (__force int)status; |
207 | |
208 | if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors))) |
209 | return "<null>" ; |
210 | return blk_errors[idx].name; |
211 | } |
212 | EXPORT_SYMBOL_GPL(blk_status_to_str); |
213 | |
214 | /** |
215 | * blk_sync_queue - cancel any pending callbacks on a queue |
216 | * @q: the queue |
217 | * |
218 | * Description: |
219 | * The block layer may perform asynchronous callback activity |
220 | * on a queue, such as calling the unplug function after a timeout. |
221 | * A block device may call blk_sync_queue to ensure that any |
222 | * such activity is cancelled, thus allowing it to release resources |
223 | * that the callbacks might use. The caller must already have made sure |
224 | * that its ->submit_bio will not re-add plugging prior to calling |
225 | * this function. |
226 | * |
227 | * This function does not cancel any asynchronous activity arising |
228 | * out of elevator or throttling code. That would require elevator_exit() |
229 | * and blkcg_exit_queue() to be called with queue lock initialized. |
230 | * |
231 | */ |
232 | void blk_sync_queue(struct request_queue *q) |
233 | { |
234 | del_timer_sync(timer: &q->timeout); |
235 | cancel_work_sync(work: &q->timeout_work); |
236 | } |
237 | EXPORT_SYMBOL(blk_sync_queue); |
238 | |
239 | /** |
240 | * blk_set_pm_only - increment pm_only counter |
241 | * @q: request queue pointer |
242 | */ |
243 | void blk_set_pm_only(struct request_queue *q) |
244 | { |
245 | atomic_inc(v: &q->pm_only); |
246 | } |
247 | EXPORT_SYMBOL_GPL(blk_set_pm_only); |
248 | |
249 | void blk_clear_pm_only(struct request_queue *q) |
250 | { |
251 | int pm_only; |
252 | |
253 | pm_only = atomic_dec_return(v: &q->pm_only); |
254 | WARN_ON_ONCE(pm_only < 0); |
255 | if (pm_only == 0) |
256 | wake_up_all(&q->mq_freeze_wq); |
257 | } |
258 | EXPORT_SYMBOL_GPL(blk_clear_pm_only); |
259 | |
260 | static void blk_free_queue_rcu(struct rcu_head *rcu_head) |
261 | { |
262 | struct request_queue *q = container_of(rcu_head, |
263 | struct request_queue, rcu_head); |
264 | |
265 | percpu_ref_exit(ref: &q->q_usage_counter); |
266 | kmem_cache_free(s: blk_requestq_cachep, objp: q); |
267 | } |
268 | |
269 | static void blk_free_queue(struct request_queue *q) |
270 | { |
271 | blk_free_queue_stats(q->stats); |
272 | if (queue_is_mq(q)) |
273 | blk_mq_release(q); |
274 | |
275 | ida_free(&blk_queue_ida, id: q->id); |
276 | call_rcu(head: &q->rcu_head, func: blk_free_queue_rcu); |
277 | } |
278 | |
279 | /** |
280 | * blk_put_queue - decrement the request_queue refcount |
281 | * @q: the request_queue structure to decrement the refcount for |
282 | * |
283 | * Decrements the refcount of the request_queue and free it when the refcount |
284 | * reaches 0. |
285 | */ |
286 | void blk_put_queue(struct request_queue *q) |
287 | { |
288 | if (refcount_dec_and_test(r: &q->refs)) |
289 | blk_free_queue(q); |
290 | } |
291 | EXPORT_SYMBOL(blk_put_queue); |
292 | |
293 | void blk_queue_start_drain(struct request_queue *q) |
294 | { |
295 | /* |
296 | * When queue DYING flag is set, we need to block new req |
297 | * entering queue, so we call blk_freeze_queue_start() to |
298 | * prevent I/O from crossing blk_queue_enter(). |
299 | */ |
300 | blk_freeze_queue_start(q); |
301 | if (queue_is_mq(q)) |
302 | blk_mq_wake_waiters(q); |
303 | /* Make blk_queue_enter() reexamine the DYING flag. */ |
304 | wake_up_all(&q->mq_freeze_wq); |
305 | } |
306 | |
307 | /** |
308 | * blk_queue_enter() - try to increase q->q_usage_counter |
309 | * @q: request queue pointer |
310 | * @flags: BLK_MQ_REQ_NOWAIT and/or BLK_MQ_REQ_PM |
311 | */ |
312 | int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags) |
313 | { |
314 | const bool pm = flags & BLK_MQ_REQ_PM; |
315 | |
316 | while (!blk_try_enter_queue(q, pm)) { |
317 | if (flags & BLK_MQ_REQ_NOWAIT) |
318 | return -EAGAIN; |
319 | |
320 | /* |
321 | * read pair of barrier in blk_freeze_queue_start(), we need to |
322 | * order reading __PERCPU_REF_DEAD flag of .q_usage_counter and |
323 | * reading .mq_freeze_depth or queue dying flag, otherwise the |
324 | * following wait may never return if the two reads are |
325 | * reordered. |
326 | */ |
327 | smp_rmb(); |
328 | wait_event(q->mq_freeze_wq, |
329 | (!q->mq_freeze_depth && |
330 | blk_pm_resume_queue(pm, q)) || |
331 | blk_queue_dying(q)); |
332 | if (blk_queue_dying(q)) |
333 | return -ENODEV; |
334 | } |
335 | |
336 | return 0; |
337 | } |
338 | |
339 | int __bio_queue_enter(struct request_queue *q, struct bio *bio) |
340 | { |
341 | while (!blk_try_enter_queue(q, pm: false)) { |
342 | struct gendisk *disk = bio->bi_bdev->bd_disk; |
343 | |
344 | if (bio->bi_opf & REQ_NOWAIT) { |
345 | if (test_bit(GD_DEAD, &disk->state)) |
346 | goto dead; |
347 | bio_wouldblock_error(bio); |
348 | return -EAGAIN; |
349 | } |
350 | |
351 | /* |
352 | * read pair of barrier in blk_freeze_queue_start(), we need to |
353 | * order reading __PERCPU_REF_DEAD flag of .q_usage_counter and |
354 | * reading .mq_freeze_depth or queue dying flag, otherwise the |
355 | * following wait may never return if the two reads are |
356 | * reordered. |
357 | */ |
358 | smp_rmb(); |
359 | wait_event(q->mq_freeze_wq, |
360 | (!q->mq_freeze_depth && |
361 | blk_pm_resume_queue(false, q)) || |
362 | test_bit(GD_DEAD, &disk->state)); |
363 | if (test_bit(GD_DEAD, &disk->state)) |
364 | goto dead; |
365 | } |
366 | |
367 | return 0; |
368 | dead: |
369 | bio_io_error(bio); |
370 | return -ENODEV; |
371 | } |
372 | |
373 | void blk_queue_exit(struct request_queue *q) |
374 | { |
375 | percpu_ref_put(ref: &q->q_usage_counter); |
376 | } |
377 | |
378 | static void blk_queue_usage_counter_release(struct percpu_ref *ref) |
379 | { |
380 | struct request_queue *q = |
381 | container_of(ref, struct request_queue, q_usage_counter); |
382 | |
383 | wake_up_all(&q->mq_freeze_wq); |
384 | } |
385 | |
386 | static void blk_rq_timed_out_timer(struct timer_list *t) |
387 | { |
388 | struct request_queue *q = from_timer(q, t, timeout); |
389 | |
390 | kblockd_schedule_work(work: &q->timeout_work); |
391 | } |
392 | |
393 | static void blk_timeout_work(struct work_struct *work) |
394 | { |
395 | } |
396 | |
397 | struct request_queue *blk_alloc_queue(struct queue_limits *lim, int node_id) |
398 | { |
399 | struct request_queue *q; |
400 | int error; |
401 | |
402 | q = kmem_cache_alloc_node(s: blk_requestq_cachep, GFP_KERNEL | __GFP_ZERO, |
403 | node: node_id); |
404 | if (!q) |
405 | return ERR_PTR(error: -ENOMEM); |
406 | |
407 | q->last_merge = NULL; |
408 | |
409 | q->id = ida_alloc(ida: &blk_queue_ida, GFP_KERNEL); |
410 | if (q->id < 0) { |
411 | error = q->id; |
412 | goto fail_q; |
413 | } |
414 | |
415 | q->stats = blk_alloc_queue_stats(); |
416 | if (!q->stats) { |
417 | error = -ENOMEM; |
418 | goto fail_id; |
419 | } |
420 | |
421 | error = blk_set_default_limits(lim); |
422 | if (error) |
423 | goto fail_stats; |
424 | q->limits = *lim; |
425 | |
426 | q->node = node_id; |
427 | |
428 | atomic_set(v: &q->nr_active_requests_shared_tags, i: 0); |
429 | |
430 | timer_setup(&q->timeout, blk_rq_timed_out_timer, 0); |
431 | INIT_WORK(&q->timeout_work, blk_timeout_work); |
432 | INIT_LIST_HEAD(list: &q->icq_list); |
433 | |
434 | refcount_set(r: &q->refs, n: 1); |
435 | mutex_init(&q->debugfs_mutex); |
436 | mutex_init(&q->sysfs_lock); |
437 | mutex_init(&q->sysfs_dir_lock); |
438 | mutex_init(&q->limits_lock); |
439 | mutex_init(&q->rq_qos_mutex); |
440 | spin_lock_init(&q->queue_lock); |
441 | |
442 | init_waitqueue_head(&q->mq_freeze_wq); |
443 | mutex_init(&q->mq_freeze_lock); |
444 | |
445 | blkg_init_queue(q); |
446 | |
447 | /* |
448 | * Init percpu_ref in atomic mode so that it's faster to shutdown. |
449 | * See blk_register_queue() for details. |
450 | */ |
451 | error = percpu_ref_init(ref: &q->q_usage_counter, |
452 | release: blk_queue_usage_counter_release, |
453 | flags: PERCPU_REF_INIT_ATOMIC, GFP_KERNEL); |
454 | if (error) |
455 | goto fail_stats; |
456 | |
457 | q->nr_requests = BLKDEV_DEFAULT_RQ; |
458 | |
459 | return q; |
460 | |
461 | fail_stats: |
462 | blk_free_queue_stats(q->stats); |
463 | fail_id: |
464 | ida_free(&blk_queue_ida, id: q->id); |
465 | fail_q: |
466 | kmem_cache_free(s: blk_requestq_cachep, objp: q); |
467 | return ERR_PTR(error); |
468 | } |
469 | |
470 | /** |
471 | * blk_get_queue - increment the request_queue refcount |
472 | * @q: the request_queue structure to increment the refcount for |
473 | * |
474 | * Increment the refcount of the request_queue kobject. |
475 | * |
476 | * Context: Any context. |
477 | */ |
478 | bool blk_get_queue(struct request_queue *q) |
479 | { |
480 | if (unlikely(blk_queue_dying(q))) |
481 | return false; |
482 | refcount_inc(r: &q->refs); |
483 | return true; |
484 | } |
485 | EXPORT_SYMBOL(blk_get_queue); |
486 | |
487 | #ifdef CONFIG_FAIL_MAKE_REQUEST |
488 | |
489 | static DECLARE_FAULT_ATTR(fail_make_request); |
490 | |
491 | static int __init setup_fail_make_request(char *str) |
492 | { |
493 | return setup_fault_attr(attr: &fail_make_request, str); |
494 | } |
495 | __setup("fail_make_request=" , setup_fail_make_request); |
496 | |
497 | bool should_fail_request(struct block_device *part, unsigned int bytes) |
498 | { |
499 | return part->bd_make_it_fail && should_fail(attr: &fail_make_request, size: bytes); |
500 | } |
501 | |
502 | static int __init fail_make_request_debugfs(void) |
503 | { |
504 | struct dentry *dir = fault_create_debugfs_attr(name: "fail_make_request" , |
505 | NULL, attr: &fail_make_request); |
506 | |
507 | return PTR_ERR_OR_ZERO(ptr: dir); |
508 | } |
509 | |
510 | late_initcall(fail_make_request_debugfs); |
511 | #endif /* CONFIG_FAIL_MAKE_REQUEST */ |
512 | |
513 | static inline void bio_check_ro(struct bio *bio) |
514 | { |
515 | if (op_is_write(op: bio_op(bio)) && bdev_read_only(bdev: bio->bi_bdev)) { |
516 | if (op_is_flush(op: bio->bi_opf) && !bio_sectors(bio)) |
517 | return; |
518 | |
519 | if (bio->bi_bdev->bd_ro_warned) |
520 | return; |
521 | |
522 | bio->bi_bdev->bd_ro_warned = true; |
523 | /* |
524 | * Use ioctl to set underlying disk of raid/dm to read-only |
525 | * will trigger this. |
526 | */ |
527 | pr_warn("Trying to write to read-only block-device %pg\n" , |
528 | bio->bi_bdev); |
529 | } |
530 | } |
531 | |
532 | static noinline int should_fail_bio(struct bio *bio) |
533 | { |
534 | if (should_fail_request(bdev_whole(bio->bi_bdev), bytes: bio->bi_iter.bi_size)) |
535 | return -EIO; |
536 | return 0; |
537 | } |
538 | ALLOW_ERROR_INJECTION(should_fail_bio, ERRNO); |
539 | |
540 | /* |
541 | * Check whether this bio extends beyond the end of the device or partition. |
542 | * This may well happen - the kernel calls bread() without checking the size of |
543 | * the device, e.g., when mounting a file system. |
544 | */ |
545 | static inline int bio_check_eod(struct bio *bio) |
546 | { |
547 | sector_t maxsector = bdev_nr_sectors(bdev: bio->bi_bdev); |
548 | unsigned int nr_sectors = bio_sectors(bio); |
549 | |
550 | if (nr_sectors && |
551 | (nr_sectors > maxsector || |
552 | bio->bi_iter.bi_sector > maxsector - nr_sectors)) { |
553 | pr_info_ratelimited("%s: attempt to access beyond end of device\n" |
554 | "%pg: rw=%d, sector=%llu, nr_sectors = %u limit=%llu\n" , |
555 | current->comm, bio->bi_bdev, bio->bi_opf, |
556 | bio->bi_iter.bi_sector, nr_sectors, maxsector); |
557 | return -EIO; |
558 | } |
559 | return 0; |
560 | } |
561 | |
562 | /* |
563 | * Remap block n of partition p to block n+start(p) of the disk. |
564 | */ |
565 | static int blk_partition_remap(struct bio *bio) |
566 | { |
567 | struct block_device *p = bio->bi_bdev; |
568 | |
569 | if (unlikely(should_fail_request(p, bio->bi_iter.bi_size))) |
570 | return -EIO; |
571 | if (bio_sectors(bio)) { |
572 | bio->bi_iter.bi_sector += p->bd_start_sect; |
573 | trace_block_bio_remap(bio, dev: p->bd_dev, |
574 | from: bio->bi_iter.bi_sector - |
575 | p->bd_start_sect); |
576 | } |
577 | bio_set_flag(bio, bit: BIO_REMAPPED); |
578 | return 0; |
579 | } |
580 | |
581 | /* |
582 | * Check write append to a zoned block device. |
583 | */ |
584 | static inline blk_status_t blk_check_zone_append(struct request_queue *q, |
585 | struct bio *bio) |
586 | { |
587 | int nr_sectors = bio_sectors(bio); |
588 | |
589 | /* Only applicable to zoned block devices */ |
590 | if (!bdev_is_zoned(bdev: bio->bi_bdev)) |
591 | return BLK_STS_NOTSUPP; |
592 | |
593 | /* The bio sector must point to the start of a sequential zone */ |
594 | if (!bdev_is_zone_start(bdev: bio->bi_bdev, sector: bio->bi_iter.bi_sector) || |
595 | !bio_zone_is_seq(bio)) |
596 | return BLK_STS_IOERR; |
597 | |
598 | /* |
599 | * Not allowed to cross zone boundaries. Otherwise, the BIO will be |
600 | * split and could result in non-contiguous sectors being written in |
601 | * different zones. |
602 | */ |
603 | if (nr_sectors > q->limits.chunk_sectors) |
604 | return BLK_STS_IOERR; |
605 | |
606 | /* Make sure the BIO is small enough and will not get split */ |
607 | if (nr_sectors > q->limits.max_zone_append_sectors) |
608 | return BLK_STS_IOERR; |
609 | |
610 | bio->bi_opf |= REQ_NOMERGE; |
611 | |
612 | return BLK_STS_OK; |
613 | } |
614 | |
615 | static void __submit_bio(struct bio *bio) |
616 | { |
617 | if (unlikely(!blk_crypto_bio_prep(&bio))) |
618 | return; |
619 | |
620 | if (!bio->bi_bdev->bd_has_submit_bio) { |
621 | blk_mq_submit_bio(bio); |
622 | } else if (likely(bio_queue_enter(bio) == 0)) { |
623 | struct gendisk *disk = bio->bi_bdev->bd_disk; |
624 | |
625 | disk->fops->submit_bio(bio); |
626 | blk_queue_exit(q: disk->queue); |
627 | } |
628 | } |
629 | |
630 | /* |
631 | * The loop in this function may be a bit non-obvious, and so deserves some |
632 | * explanation: |
633 | * |
634 | * - Before entering the loop, bio->bi_next is NULL (as all callers ensure |
635 | * that), so we have a list with a single bio. |
636 | * - We pretend that we have just taken it off a longer list, so we assign |
637 | * bio_list to a pointer to the bio_list_on_stack, thus initialising the |
638 | * bio_list of new bios to be added. ->submit_bio() may indeed add some more |
639 | * bios through a recursive call to submit_bio_noacct. If it did, we find a |
640 | * non-NULL value in bio_list and re-enter the loop from the top. |
641 | * - In this case we really did just take the bio of the top of the list (no |
642 | * pretending) and so remove it from bio_list, and call into ->submit_bio() |
643 | * again. |
644 | * |
645 | * bio_list_on_stack[0] contains bios submitted by the current ->submit_bio. |
646 | * bio_list_on_stack[1] contains bios that were submitted before the current |
647 | * ->submit_bio, but that haven't been processed yet. |
648 | */ |
649 | static void __submit_bio_noacct(struct bio *bio) |
650 | { |
651 | struct bio_list bio_list_on_stack[2]; |
652 | |
653 | BUG_ON(bio->bi_next); |
654 | |
655 | bio_list_init(bl: &bio_list_on_stack[0]); |
656 | current->bio_list = bio_list_on_stack; |
657 | |
658 | do { |
659 | struct request_queue *q = bdev_get_queue(bdev: bio->bi_bdev); |
660 | struct bio_list lower, same; |
661 | |
662 | /* |
663 | * Create a fresh bio_list for all subordinate requests. |
664 | */ |
665 | bio_list_on_stack[1] = bio_list_on_stack[0]; |
666 | bio_list_init(bl: &bio_list_on_stack[0]); |
667 | |
668 | __submit_bio(bio); |
669 | |
670 | /* |
671 | * Sort new bios into those for a lower level and those for the |
672 | * same level. |
673 | */ |
674 | bio_list_init(bl: &lower); |
675 | bio_list_init(bl: &same); |
676 | while ((bio = bio_list_pop(bl: &bio_list_on_stack[0])) != NULL) |
677 | if (q == bdev_get_queue(bdev: bio->bi_bdev)) |
678 | bio_list_add(bl: &same, bio); |
679 | else |
680 | bio_list_add(bl: &lower, bio); |
681 | |
682 | /* |
683 | * Now assemble so we handle the lowest level first. |
684 | */ |
685 | bio_list_merge(bl: &bio_list_on_stack[0], bl2: &lower); |
686 | bio_list_merge(bl: &bio_list_on_stack[0], bl2: &same); |
687 | bio_list_merge(bl: &bio_list_on_stack[0], bl2: &bio_list_on_stack[1]); |
688 | } while ((bio = bio_list_pop(bl: &bio_list_on_stack[0]))); |
689 | |
690 | current->bio_list = NULL; |
691 | } |
692 | |
693 | static void __submit_bio_noacct_mq(struct bio *bio) |
694 | { |
695 | struct bio_list bio_list[2] = { }; |
696 | |
697 | current->bio_list = bio_list; |
698 | |
699 | do { |
700 | __submit_bio(bio); |
701 | } while ((bio = bio_list_pop(bl: &bio_list[0]))); |
702 | |
703 | current->bio_list = NULL; |
704 | } |
705 | |
706 | void submit_bio_noacct_nocheck(struct bio *bio) |
707 | { |
708 | blk_cgroup_bio_start(bio); |
709 | blkcg_bio_issue_init(bio); |
710 | |
711 | if (!bio_flagged(bio, bit: BIO_TRACE_COMPLETION)) { |
712 | trace_block_bio_queue(bio); |
713 | /* |
714 | * Now that enqueuing has been traced, we need to trace |
715 | * completion as well. |
716 | */ |
717 | bio_set_flag(bio, bit: BIO_TRACE_COMPLETION); |
718 | } |
719 | |
720 | /* |
721 | * We only want one ->submit_bio to be active at a time, else stack |
722 | * usage with stacked devices could be a problem. Use current->bio_list |
723 | * to collect a list of requests submited by a ->submit_bio method while |
724 | * it is active, and then process them after it returned. |
725 | */ |
726 | if (current->bio_list) |
727 | bio_list_add(bl: ¤t->bio_list[0], bio); |
728 | else if (!bio->bi_bdev->bd_has_submit_bio) |
729 | __submit_bio_noacct_mq(bio); |
730 | else |
731 | __submit_bio_noacct(bio); |
732 | } |
733 | |
734 | /** |
735 | * submit_bio_noacct - re-submit a bio to the block device layer for I/O |
736 | * @bio: The bio describing the location in memory and on the device. |
737 | * |
738 | * This is a version of submit_bio() that shall only be used for I/O that is |
739 | * resubmitted to lower level drivers by stacking block drivers. All file |
740 | * systems and other upper level users of the block layer should use |
741 | * submit_bio() instead. |
742 | */ |
743 | void submit_bio_noacct(struct bio *bio) |
744 | { |
745 | struct block_device *bdev = bio->bi_bdev; |
746 | struct request_queue *q = bdev_get_queue(bdev); |
747 | blk_status_t status = BLK_STS_IOERR; |
748 | |
749 | might_sleep(); |
750 | |
751 | /* |
752 | * For a REQ_NOWAIT based request, return -EOPNOTSUPP |
753 | * if queue does not support NOWAIT. |
754 | */ |
755 | if ((bio->bi_opf & REQ_NOWAIT) && !bdev_nowait(bdev)) |
756 | goto not_supported; |
757 | |
758 | if (should_fail_bio(bio)) |
759 | goto end_io; |
760 | bio_check_ro(bio); |
761 | if (!bio_flagged(bio, bit: BIO_REMAPPED)) { |
762 | if (unlikely(bio_check_eod(bio))) |
763 | goto end_io; |
764 | if (bdev->bd_partno && unlikely(blk_partition_remap(bio))) |
765 | goto end_io; |
766 | } |
767 | |
768 | /* |
769 | * Filter flush bio's early so that bio based drivers without flush |
770 | * support don't have to worry about them. |
771 | */ |
772 | if (op_is_flush(op: bio->bi_opf)) { |
773 | if (WARN_ON_ONCE(bio_op(bio) != REQ_OP_WRITE && |
774 | bio_op(bio) != REQ_OP_ZONE_APPEND)) |
775 | goto end_io; |
776 | if (!test_bit(QUEUE_FLAG_WC, &q->queue_flags)) { |
777 | bio->bi_opf &= ~(REQ_PREFLUSH | REQ_FUA); |
778 | if (!bio_sectors(bio)) { |
779 | status = BLK_STS_OK; |
780 | goto end_io; |
781 | } |
782 | } |
783 | } |
784 | |
785 | if (!test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) |
786 | bio_clear_polled(bio); |
787 | |
788 | switch (bio_op(bio)) { |
789 | case REQ_OP_READ: |
790 | case REQ_OP_WRITE: |
791 | break; |
792 | case REQ_OP_FLUSH: |
793 | /* |
794 | * REQ_OP_FLUSH can't be submitted through bios, it is only |
795 | * synthetized in struct request by the flush state machine. |
796 | */ |
797 | goto not_supported; |
798 | case REQ_OP_DISCARD: |
799 | if (!bdev_max_discard_sectors(bdev)) |
800 | goto not_supported; |
801 | break; |
802 | case REQ_OP_SECURE_ERASE: |
803 | if (!bdev_max_secure_erase_sectors(bdev)) |
804 | goto not_supported; |
805 | break; |
806 | case REQ_OP_ZONE_APPEND: |
807 | status = blk_check_zone_append(q, bio); |
808 | if (status != BLK_STS_OK) |
809 | goto end_io; |
810 | break; |
811 | case REQ_OP_WRITE_ZEROES: |
812 | if (!q->limits.max_write_zeroes_sectors) |
813 | goto not_supported; |
814 | break; |
815 | case REQ_OP_ZONE_RESET: |
816 | case REQ_OP_ZONE_OPEN: |
817 | case REQ_OP_ZONE_CLOSE: |
818 | case REQ_OP_ZONE_FINISH: |
819 | if (!bdev_is_zoned(bdev: bio->bi_bdev)) |
820 | goto not_supported; |
821 | break; |
822 | case REQ_OP_ZONE_RESET_ALL: |
823 | if (!bdev_is_zoned(bdev: bio->bi_bdev) || !blk_queue_zone_resetall(q)) |
824 | goto not_supported; |
825 | break; |
826 | case REQ_OP_DRV_IN: |
827 | case REQ_OP_DRV_OUT: |
828 | /* |
829 | * Driver private operations are only used with passthrough |
830 | * requests. |
831 | */ |
832 | fallthrough; |
833 | default: |
834 | goto not_supported; |
835 | } |
836 | |
837 | if (blk_throtl_bio(bio)) |
838 | return; |
839 | submit_bio_noacct_nocheck(bio); |
840 | return; |
841 | |
842 | not_supported: |
843 | status = BLK_STS_NOTSUPP; |
844 | end_io: |
845 | bio->bi_status = status; |
846 | bio_endio(bio); |
847 | } |
848 | EXPORT_SYMBOL(submit_bio_noacct); |
849 | |
850 | static void bio_set_ioprio(struct bio *bio) |
851 | { |
852 | /* Nobody set ioprio so far? Initialize it based on task's nice value */ |
853 | if (IOPRIO_PRIO_CLASS(bio->bi_ioprio) == IOPRIO_CLASS_NONE) |
854 | bio->bi_ioprio = get_current_ioprio(); |
855 | blkcg_set_ioprio(bio); |
856 | } |
857 | |
858 | /** |
859 | * submit_bio - submit a bio to the block device layer for I/O |
860 | * @bio: The &struct bio which describes the I/O |
861 | * |
862 | * submit_bio() is used to submit I/O requests to block devices. It is passed a |
863 | * fully set up &struct bio that describes the I/O that needs to be done. The |
864 | * bio will be send to the device described by the bi_bdev field. |
865 | * |
866 | * The success/failure status of the request, along with notification of |
867 | * completion, is delivered asynchronously through the ->bi_end_io() callback |
868 | * in @bio. The bio must NOT be touched by the caller until ->bi_end_io() has |
869 | * been called. |
870 | */ |
871 | void submit_bio(struct bio *bio) |
872 | { |
873 | if (bio_op(bio) == REQ_OP_READ) { |
874 | task_io_account_read(bytes: bio->bi_iter.bi_size); |
875 | count_vm_events(item: PGPGIN, bio_sectors(bio)); |
876 | } else if (bio_op(bio) == REQ_OP_WRITE) { |
877 | count_vm_events(item: PGPGOUT, bio_sectors(bio)); |
878 | } |
879 | |
880 | bio_set_ioprio(bio); |
881 | submit_bio_noacct(bio); |
882 | } |
883 | EXPORT_SYMBOL(submit_bio); |
884 | |
885 | /** |
886 | * bio_poll - poll for BIO completions |
887 | * @bio: bio to poll for |
888 | * @iob: batches of IO |
889 | * @flags: BLK_POLL_* flags that control the behavior |
890 | * |
891 | * Poll for completions on queue associated with the bio. Returns number of |
892 | * completed entries found. |
893 | * |
894 | * Note: the caller must either be the context that submitted @bio, or |
895 | * be in a RCU critical section to prevent freeing of @bio. |
896 | */ |
897 | int bio_poll(struct bio *bio, struct io_comp_batch *iob, unsigned int flags) |
898 | { |
899 | blk_qc_t cookie = READ_ONCE(bio->bi_cookie); |
900 | struct block_device *bdev; |
901 | struct request_queue *q; |
902 | int ret = 0; |
903 | |
904 | bdev = READ_ONCE(bio->bi_bdev); |
905 | if (!bdev) |
906 | return 0; |
907 | |
908 | q = bdev_get_queue(bdev); |
909 | if (cookie == BLK_QC_T_NONE || |
910 | !test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) |
911 | return 0; |
912 | |
913 | /* |
914 | * As the requests that require a zone lock are not plugged in the |
915 | * first place, directly accessing the plug instead of using |
916 | * blk_mq_plug() should not have any consequences during flushing for |
917 | * zoned devices. |
918 | */ |
919 | blk_flush_plug(current->plug, async: false); |
920 | |
921 | /* |
922 | * We need to be able to enter a frozen queue, similar to how |
923 | * timeouts also need to do that. If that is blocked, then we can |
924 | * have pending IO when a queue freeze is started, and then the |
925 | * wait for the freeze to finish will wait for polled requests to |
926 | * timeout as the poller is preventer from entering the queue and |
927 | * completing them. As long as we prevent new IO from being queued, |
928 | * that should be all that matters. |
929 | */ |
930 | if (!percpu_ref_tryget(ref: &q->q_usage_counter)) |
931 | return 0; |
932 | if (queue_is_mq(q)) { |
933 | ret = blk_mq_poll(q, cookie, iob, flags); |
934 | } else { |
935 | struct gendisk *disk = q->disk; |
936 | |
937 | if (disk && disk->fops->poll_bio) |
938 | ret = disk->fops->poll_bio(bio, iob, flags); |
939 | } |
940 | blk_queue_exit(q); |
941 | return ret; |
942 | } |
943 | EXPORT_SYMBOL_GPL(bio_poll); |
944 | |
945 | /* |
946 | * Helper to implement file_operations.iopoll. Requires the bio to be stored |
947 | * in iocb->private, and cleared before freeing the bio. |
948 | */ |
949 | int iocb_bio_iopoll(struct kiocb *kiocb, struct io_comp_batch *iob, |
950 | unsigned int flags) |
951 | { |
952 | struct bio *bio; |
953 | int ret = 0; |
954 | |
955 | /* |
956 | * Note: the bio cache only uses SLAB_TYPESAFE_BY_RCU, so bio can |
957 | * point to a freshly allocated bio at this point. If that happens |
958 | * we have a few cases to consider: |
959 | * |
960 | * 1) the bio is beeing initialized and bi_bdev is NULL. We can just |
961 | * simply nothing in this case |
962 | * 2) the bio points to a not poll enabled device. bio_poll will catch |
963 | * this and return 0 |
964 | * 3) the bio points to a poll capable device, including but not |
965 | * limited to the one that the original bio pointed to. In this |
966 | * case we will call into the actual poll method and poll for I/O, |
967 | * even if we don't need to, but it won't cause harm either. |
968 | * |
969 | * For cases 2) and 3) above the RCU grace period ensures that bi_bdev |
970 | * is still allocated. Because partitions hold a reference to the whole |
971 | * device bdev and thus disk, the disk is also still valid. Grabbing |
972 | * a reference to the queue in bio_poll() ensures the hctxs and requests |
973 | * are still valid as well. |
974 | */ |
975 | rcu_read_lock(); |
976 | bio = READ_ONCE(kiocb->private); |
977 | if (bio) |
978 | ret = bio_poll(bio, iob, flags); |
979 | rcu_read_unlock(); |
980 | |
981 | return ret; |
982 | } |
983 | EXPORT_SYMBOL_GPL(iocb_bio_iopoll); |
984 | |
985 | void update_io_ticks(struct block_device *part, unsigned long now, bool end) |
986 | { |
987 | unsigned long stamp; |
988 | again: |
989 | stamp = READ_ONCE(part->bd_stamp); |
990 | if (unlikely(time_after(now, stamp))) { |
991 | if (likely(try_cmpxchg(&part->bd_stamp, &stamp, now))) |
992 | __part_stat_add(part, io_ticks, end ? now - stamp : 1); |
993 | } |
994 | if (part->bd_partno) { |
995 | part = bdev_whole(part); |
996 | goto again; |
997 | } |
998 | } |
999 | |
1000 | unsigned long bdev_start_io_acct(struct block_device *bdev, enum req_op op, |
1001 | unsigned long start_time) |
1002 | { |
1003 | part_stat_lock(); |
1004 | update_io_ticks(part: bdev, now: start_time, end: false); |
1005 | part_stat_local_inc(bdev, in_flight[op_is_write(op)]); |
1006 | part_stat_unlock(); |
1007 | |
1008 | return start_time; |
1009 | } |
1010 | EXPORT_SYMBOL(bdev_start_io_acct); |
1011 | |
1012 | /** |
1013 | * bio_start_io_acct - start I/O accounting for bio based drivers |
1014 | * @bio: bio to start account for |
1015 | * |
1016 | * Returns the start time that should be passed back to bio_end_io_acct(). |
1017 | */ |
1018 | unsigned long bio_start_io_acct(struct bio *bio) |
1019 | { |
1020 | return bdev_start_io_acct(bio->bi_bdev, bio_op(bio), jiffies); |
1021 | } |
1022 | EXPORT_SYMBOL_GPL(bio_start_io_acct); |
1023 | |
1024 | void bdev_end_io_acct(struct block_device *bdev, enum req_op op, |
1025 | unsigned int sectors, unsigned long start_time) |
1026 | { |
1027 | const int sgrp = op_stat_group(op); |
1028 | unsigned long now = READ_ONCE(jiffies); |
1029 | unsigned long duration = now - start_time; |
1030 | |
1031 | part_stat_lock(); |
1032 | update_io_ticks(part: bdev, now, end: true); |
1033 | part_stat_inc(bdev, ios[sgrp]); |
1034 | part_stat_add(bdev, sectors[sgrp], sectors); |
1035 | part_stat_add(bdev, nsecs[sgrp], jiffies_to_nsecs(duration)); |
1036 | part_stat_local_dec(bdev, in_flight[op_is_write(op)]); |
1037 | part_stat_unlock(); |
1038 | } |
1039 | EXPORT_SYMBOL(bdev_end_io_acct); |
1040 | |
1041 | void bio_end_io_acct_remapped(struct bio *bio, unsigned long start_time, |
1042 | struct block_device *orig_bdev) |
1043 | { |
1044 | bdev_end_io_acct(orig_bdev, bio_op(bio), bio_sectors(bio), start_time); |
1045 | } |
1046 | EXPORT_SYMBOL_GPL(bio_end_io_acct_remapped); |
1047 | |
1048 | /** |
1049 | * blk_lld_busy - Check if underlying low-level drivers of a device are busy |
1050 | * @q : the queue of the device being checked |
1051 | * |
1052 | * Description: |
1053 | * Check if underlying low-level drivers of a device are busy. |
1054 | * If the drivers want to export their busy state, they must set own |
1055 | * exporting function using blk_queue_lld_busy() first. |
1056 | * |
1057 | * Basically, this function is used only by request stacking drivers |
1058 | * to stop dispatching requests to underlying devices when underlying |
1059 | * devices are busy. This behavior helps more I/O merging on the queue |
1060 | * of the request stacking driver and prevents I/O throughput regression |
1061 | * on burst I/O load. |
1062 | * |
1063 | * Return: |
1064 | * 0 - Not busy (The request stacking driver should dispatch request) |
1065 | * 1 - Busy (The request stacking driver should stop dispatching request) |
1066 | */ |
1067 | int blk_lld_busy(struct request_queue *q) |
1068 | { |
1069 | if (queue_is_mq(q) && q->mq_ops->busy) |
1070 | return q->mq_ops->busy(q); |
1071 | |
1072 | return 0; |
1073 | } |
1074 | EXPORT_SYMBOL_GPL(blk_lld_busy); |
1075 | |
1076 | int kblockd_schedule_work(struct work_struct *work) |
1077 | { |
1078 | return queue_work(wq: kblockd_workqueue, work); |
1079 | } |
1080 | EXPORT_SYMBOL(kblockd_schedule_work); |
1081 | |
1082 | int kblockd_mod_delayed_work_on(int cpu, struct delayed_work *dwork, |
1083 | unsigned long delay) |
1084 | { |
1085 | return mod_delayed_work_on(cpu, wq: kblockd_workqueue, dwork, delay); |
1086 | } |
1087 | EXPORT_SYMBOL(kblockd_mod_delayed_work_on); |
1088 | |
1089 | void blk_start_plug_nr_ios(struct blk_plug *plug, unsigned short nr_ios) |
1090 | { |
1091 | struct task_struct *tsk = current; |
1092 | |
1093 | /* |
1094 | * If this is a nested plug, don't actually assign it. |
1095 | */ |
1096 | if (tsk->plug) |
1097 | return; |
1098 | |
1099 | plug->cur_ktime = 0; |
1100 | plug->mq_list = NULL; |
1101 | plug->cached_rq = NULL; |
1102 | plug->nr_ios = min_t(unsigned short, nr_ios, BLK_MAX_REQUEST_COUNT); |
1103 | plug->rq_count = 0; |
1104 | plug->multiple_queues = false; |
1105 | plug->has_elevator = false; |
1106 | INIT_LIST_HEAD(list: &plug->cb_list); |
1107 | |
1108 | /* |
1109 | * Store ordering should not be needed here, since a potential |
1110 | * preempt will imply a full memory barrier |
1111 | */ |
1112 | tsk->plug = plug; |
1113 | } |
1114 | |
1115 | /** |
1116 | * blk_start_plug - initialize blk_plug and track it inside the task_struct |
1117 | * @plug: The &struct blk_plug that needs to be initialized |
1118 | * |
1119 | * Description: |
1120 | * blk_start_plug() indicates to the block layer an intent by the caller |
1121 | * to submit multiple I/O requests in a batch. The block layer may use |
1122 | * this hint to defer submitting I/Os from the caller until blk_finish_plug() |
1123 | * is called. However, the block layer may choose to submit requests |
1124 | * before a call to blk_finish_plug() if the number of queued I/Os |
1125 | * exceeds %BLK_MAX_REQUEST_COUNT, or if the size of the I/O is larger than |
1126 | * %BLK_PLUG_FLUSH_SIZE. The queued I/Os may also be submitted early if |
1127 | * the task schedules (see below). |
1128 | * |
1129 | * Tracking blk_plug inside the task_struct will help with auto-flushing the |
1130 | * pending I/O should the task end up blocking between blk_start_plug() and |
1131 | * blk_finish_plug(). This is important from a performance perspective, but |
1132 | * also ensures that we don't deadlock. For instance, if the task is blocking |
1133 | * for a memory allocation, memory reclaim could end up wanting to free a |
1134 | * page belonging to that request that is currently residing in our private |
1135 | * plug. By flushing the pending I/O when the process goes to sleep, we avoid |
1136 | * this kind of deadlock. |
1137 | */ |
1138 | void blk_start_plug(struct blk_plug *plug) |
1139 | { |
1140 | blk_start_plug_nr_ios(plug, nr_ios: 1); |
1141 | } |
1142 | EXPORT_SYMBOL(blk_start_plug); |
1143 | |
1144 | static void flush_plug_callbacks(struct blk_plug *plug, bool from_schedule) |
1145 | { |
1146 | LIST_HEAD(callbacks); |
1147 | |
1148 | while (!list_empty(head: &plug->cb_list)) { |
1149 | list_splice_init(list: &plug->cb_list, head: &callbacks); |
1150 | |
1151 | while (!list_empty(head: &callbacks)) { |
1152 | struct blk_plug_cb *cb = list_first_entry(&callbacks, |
1153 | struct blk_plug_cb, |
1154 | list); |
1155 | list_del(entry: &cb->list); |
1156 | cb->callback(cb, from_schedule); |
1157 | } |
1158 | } |
1159 | } |
1160 | |
1161 | struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug, void *data, |
1162 | int size) |
1163 | { |
1164 | struct blk_plug *plug = current->plug; |
1165 | struct blk_plug_cb *cb; |
1166 | |
1167 | if (!plug) |
1168 | return NULL; |
1169 | |
1170 | list_for_each_entry(cb, &plug->cb_list, list) |
1171 | if (cb->callback == unplug && cb->data == data) |
1172 | return cb; |
1173 | |
1174 | /* Not currently on the callback list */ |
1175 | BUG_ON(size < sizeof(*cb)); |
1176 | cb = kzalloc(size, GFP_ATOMIC); |
1177 | if (cb) { |
1178 | cb->data = data; |
1179 | cb->callback = unplug; |
1180 | list_add(new: &cb->list, head: &plug->cb_list); |
1181 | } |
1182 | return cb; |
1183 | } |
1184 | EXPORT_SYMBOL(blk_check_plugged); |
1185 | |
1186 | void __blk_flush_plug(struct blk_plug *plug, bool from_schedule) |
1187 | { |
1188 | if (!list_empty(head: &plug->cb_list)) |
1189 | flush_plug_callbacks(plug, from_schedule); |
1190 | blk_mq_flush_plug_list(plug, from_schedule); |
1191 | /* |
1192 | * Unconditionally flush out cached requests, even if the unplug |
1193 | * event came from schedule. Since we know hold references to the |
1194 | * queue for cached requests, we don't want a blocked task holding |
1195 | * up a queue freeze/quiesce event. |
1196 | */ |
1197 | if (unlikely(!rq_list_empty(plug->cached_rq))) |
1198 | blk_mq_free_plug_rqs(plug); |
1199 | |
1200 | plug->cur_ktime = 0; |
1201 | current->flags &= ~PF_BLOCK_TS; |
1202 | } |
1203 | |
1204 | /** |
1205 | * blk_finish_plug - mark the end of a batch of submitted I/O |
1206 | * @plug: The &struct blk_plug passed to blk_start_plug() |
1207 | * |
1208 | * Description: |
1209 | * Indicate that a batch of I/O submissions is complete. This function |
1210 | * must be paired with an initial call to blk_start_plug(). The intent |
1211 | * is to allow the block layer to optimize I/O submission. See the |
1212 | * documentation for blk_start_plug() for more information. |
1213 | */ |
1214 | void blk_finish_plug(struct blk_plug *plug) |
1215 | { |
1216 | if (plug == current->plug) { |
1217 | __blk_flush_plug(plug, from_schedule: false); |
1218 | current->plug = NULL; |
1219 | } |
1220 | } |
1221 | EXPORT_SYMBOL(blk_finish_plug); |
1222 | |
1223 | void blk_io_schedule(void) |
1224 | { |
1225 | /* Prevent hang_check timer from firing at us during very long I/O */ |
1226 | unsigned long timeout = sysctl_hung_task_timeout_secs * HZ / 2; |
1227 | |
1228 | if (timeout) |
1229 | io_schedule_timeout(timeout); |
1230 | else |
1231 | io_schedule(); |
1232 | } |
1233 | EXPORT_SYMBOL_GPL(blk_io_schedule); |
1234 | |
1235 | int __init blk_dev_init(void) |
1236 | { |
1237 | BUILD_BUG_ON((__force u32)REQ_OP_LAST >= (1 << REQ_OP_BITS)); |
1238 | BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 * |
1239 | sizeof_field(struct request, cmd_flags)); |
1240 | BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 * |
1241 | sizeof_field(struct bio, bi_opf)); |
1242 | |
1243 | /* used for unplugging and affects IO latency/throughput - HIGHPRI */ |
1244 | kblockd_workqueue = alloc_workqueue(fmt: "kblockd" , |
1245 | flags: WQ_MEM_RECLAIM | WQ_HIGHPRI, max_active: 0); |
1246 | if (!kblockd_workqueue) |
1247 | panic(fmt: "Failed to create kblockd\n" ); |
1248 | |
1249 | blk_requestq_cachep = KMEM_CACHE(request_queue, SLAB_PANIC); |
1250 | |
1251 | blk_debugfs_root = debugfs_create_dir(name: "block" , NULL); |
1252 | |
1253 | return 0; |
1254 | } |
1255 | |