Line data Source code
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 :
55 : struct dentry *blk_debugfs_root;
56 :
57 : EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap);
58 : EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap);
59 : EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete);
60 : EXPORT_TRACEPOINT_SYMBOL_GPL(block_split);
61 : EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug);
62 : EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_insert);
63 :
64 : DEFINE_IDA(blk_queue_ida);
65 :
66 : /*
67 : * For queue allocation
68 : */
69 : struct kmem_cache *blk_requestq_cachep;
70 :
71 : /*
72 : * Controlling structure to kblockd
73 : */
74 : static 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 : */
81 28 : void blk_queue_flag_set(unsigned int flag, struct request_queue *q)
82 : {
83 28 : set_bit(flag, &q->queue_flags);
84 28 : }
85 : EXPORT_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 : */
92 1 : void blk_queue_flag_clear(unsigned int flag, struct request_queue *q)
93 : {
94 1 : clear_bit(flag, &q->queue_flags);
95 1 : }
96 : EXPORT_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 : */
106 0 : bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q)
107 : {
108 0 : return test_and_set_bit(flag, &q->queue_flags);
109 : }
110 : EXPORT_SYMBOL_GPL(blk_queue_flag_test_and_set);
111 :
112 191 : void blk_rq_init(struct request_queue *q, struct request *rq)
113 : {
114 191 : memset(rq, 0, sizeof(*rq));
115 :
116 191 : INIT_LIST_HEAD(&rq->queuelist);
117 191 : rq->q = q;
118 191 : rq->__sector = (sector_t) -1;
119 191 : INIT_HLIST_NODE(&rq->hash);
120 191 : RB_CLEAR_NODE(&rq->rb_node);
121 191 : rq->tag = BLK_MQ_NO_TAG;
122 191 : rq->internal_tag = BLK_MQ_NO_TAG;
123 191 : rq->start_time_ns = ktime_get_ns();
124 191 : rq->part = NULL;
125 191 : refcount_set(&rq->ref, 1);
126 191 : blk_crypto_rq_set_defaults(rq);
127 191 : }
128 : EXPORT_SYMBOL(blk_rq_init);
129 :
130 : #define REQ_OP_NAME(name) [REQ_OP_##name] = #name
131 : static const char *const blk_op_name[] = {
132 : REQ_OP_NAME(READ),
133 : REQ_OP_NAME(WRITE),
134 : REQ_OP_NAME(FLUSH),
135 : REQ_OP_NAME(DISCARD),
136 : REQ_OP_NAME(SECURE_ERASE),
137 : REQ_OP_NAME(ZONE_RESET),
138 : REQ_OP_NAME(ZONE_RESET_ALL),
139 : REQ_OP_NAME(ZONE_OPEN),
140 : REQ_OP_NAME(ZONE_CLOSE),
141 : REQ_OP_NAME(ZONE_FINISH),
142 : REQ_OP_NAME(ZONE_APPEND),
143 : REQ_OP_NAME(WRITE_SAME),
144 : REQ_OP_NAME(WRITE_ZEROES),
145 : REQ_OP_NAME(SCSI_IN),
146 : REQ_OP_NAME(SCSI_OUT),
147 : REQ_OP_NAME(DRV_IN),
148 : REQ_OP_NAME(DRV_OUT),
149 : };
150 : #undef REQ_OP_NAME
151 :
152 : /**
153 : * blk_op_str - Return string XXX in the REQ_OP_XXX.
154 : * @op: REQ_OP_XXX.
155 : *
156 : * Description: Centralize block layer function to convert REQ_OP_XXX into
157 : * string format. Useful in the debugging and tracing bio or request. For
158 : * invalid REQ_OP_XXX it returns string "UNKNOWN".
159 : */
160 0 : inline const char *blk_op_str(unsigned int op)
161 : {
162 0 : const char *op_str = "UNKNOWN";
163 :
164 0 : if (op < ARRAY_SIZE(blk_op_name) && blk_op_name[op])
165 0 : op_str = blk_op_name[op];
166 :
167 0 : return op_str;
168 : }
169 : EXPORT_SYMBOL_GPL(blk_op_str);
170 :
171 : static const struct {
172 : int errno;
173 : const char *name;
174 : } blk_errors[] = {
175 : [BLK_STS_OK] = { 0, "" },
176 : [BLK_STS_NOTSUPP] = { -EOPNOTSUPP, "operation not supported" },
177 : [BLK_STS_TIMEOUT] = { -ETIMEDOUT, "timeout" },
178 : [BLK_STS_NOSPC] = { -ENOSPC, "critical space allocation" },
179 : [BLK_STS_TRANSPORT] = { -ENOLINK, "recoverable transport" },
180 : [BLK_STS_TARGET] = { -EREMOTEIO, "critical target" },
181 : [BLK_STS_NEXUS] = { -EBADE, "critical nexus" },
182 : [BLK_STS_MEDIUM] = { -ENODATA, "critical medium" },
183 : [BLK_STS_PROTECTION] = { -EILSEQ, "protection" },
184 : [BLK_STS_RESOURCE] = { -ENOMEM, "kernel resource" },
185 : [BLK_STS_DEV_RESOURCE] = { -EBUSY, "device resource" },
186 : [BLK_STS_AGAIN] = { -EAGAIN, "nonblocking retry" },
187 :
188 : /* device mapper special case, should not leak out: */
189 : [BLK_STS_DM_REQUEUE] = { -EREMCHG, "dm internal retry" },
190 :
191 : /* zone device specific errors */
192 : [BLK_STS_ZONE_OPEN_RESOURCE] = { -ETOOMANYREFS, "open zones exceeded" },
193 : [BLK_STS_ZONE_ACTIVE_RESOURCE] = { -EOVERFLOW, "active zones exceeded" },
194 :
195 : /* everything else not covered above: */
196 : [BLK_STS_IOERR] = { -EIO, "I/O" },
197 : };
198 :
199 0 : blk_status_t errno_to_blk_status(int errno)
200 : {
201 0 : int i;
202 :
203 0 : for (i = 0; i < ARRAY_SIZE(blk_errors); i++) {
204 0 : if (blk_errors[i].errno == errno)
205 0 : return (__force blk_status_t)i;
206 : }
207 :
208 : return BLK_STS_IOERR;
209 : }
210 : EXPORT_SYMBOL_GPL(errno_to_blk_status);
211 :
212 4095 : int blk_status_to_errno(blk_status_t status)
213 : {
214 4095 : int idx = (__force int)status;
215 :
216 4095 : if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors)))
217 : return -EIO;
218 4095 : return blk_errors[idx].errno;
219 : }
220 : EXPORT_SYMBOL_GPL(blk_status_to_errno);
221 :
222 0 : static void print_req_error(struct request *req, blk_status_t status,
223 : const char *caller)
224 : {
225 0 : int idx = (__force int)status;
226 :
227 0 : if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors)))
228 : return;
229 :
230 0 : printk_ratelimited(KERN_ERR
231 : "%s: %s error, dev %s, sector %llu op 0x%x:(%s) flags 0x%x "
232 : "phys_seg %u prio class %u\n",
233 : caller, blk_errors[idx].name,
234 : req->rq_disk ? req->rq_disk->disk_name : "?",
235 : blk_rq_pos(req), req_op(req), blk_op_str(req_op(req)),
236 : req->cmd_flags & ~REQ_OP_MASK,
237 : req->nr_phys_segments,
238 : IOPRIO_PRIO_CLASS(req->ioprio));
239 : }
240 :
241 8799 : static void req_bio_endio(struct request *rq, struct bio *bio,
242 : unsigned int nbytes, blk_status_t error)
243 : {
244 8799 : if (error)
245 0 : bio->bi_status = error;
246 :
247 8799 : if (unlikely(rq->rq_flags & RQF_QUIET))
248 0 : bio_set_flag(bio, BIO_QUIET);
249 :
250 8799 : bio_advance(bio, nbytes);
251 :
252 8798 : if (req_op(rq) == REQ_OP_ZONE_APPEND && error == BLK_STS_OK) {
253 : /*
254 : * Partial zone append completions cannot be supported as the
255 : * BIO fragments may end up not being written sequentially.
256 : */
257 0 : if (bio->bi_iter.bi_size)
258 0 : bio->bi_status = BLK_STS_IOERR;
259 : else
260 0 : bio->bi_iter.bi_sector = rq->__sector;
261 : }
262 :
263 : /* don't actually finish bio if it's part of flush sequence */
264 8798 : if (bio->bi_iter.bi_size == 0 && !(rq->rq_flags & RQF_FLUSH_SEQ))
265 8738 : bio_endio(bio);
266 8799 : }
267 :
268 0 : void blk_dump_rq_flags(struct request *rq, char *msg)
269 : {
270 0 : printk(KERN_INFO "%s: dev %s: flags=%llx\n", msg,
271 0 : rq->rq_disk ? rq->rq_disk->disk_name : "?",
272 0 : (unsigned long long) rq->cmd_flags);
273 :
274 0 : printk(KERN_INFO " sector %llu, nr/cnr %u/%u\n",
275 0 : (unsigned long long)blk_rq_pos(rq),
276 : blk_rq_sectors(rq), blk_rq_cur_sectors(rq));
277 0 : printk(KERN_INFO " bio %p, biotail %p, len %u\n",
278 : rq->bio, rq->biotail, blk_rq_bytes(rq));
279 0 : }
280 : EXPORT_SYMBOL(blk_dump_rq_flags);
281 :
282 : /**
283 : * blk_sync_queue - cancel any pending callbacks on a queue
284 : * @q: the queue
285 : *
286 : * Description:
287 : * The block layer may perform asynchronous callback activity
288 : * on a queue, such as calling the unplug function after a timeout.
289 : * A block device may call blk_sync_queue to ensure that any
290 : * such activity is cancelled, thus allowing it to release resources
291 : * that the callbacks might use. The caller must already have made sure
292 : * that its ->submit_bio will not re-add plugging prior to calling
293 : * this function.
294 : *
295 : * This function does not cancel any asynchronous activity arising
296 : * out of elevator or throttling code. That would require elevator_exit()
297 : * and blkcg_exit_queue() to be called with queue lock initialized.
298 : *
299 : */
300 0 : void blk_sync_queue(struct request_queue *q)
301 : {
302 0 : del_timer_sync(&q->timeout);
303 0 : cancel_work_sync(&q->timeout_work);
304 0 : }
305 : EXPORT_SYMBOL(blk_sync_queue);
306 :
307 : /**
308 : * blk_set_pm_only - increment pm_only counter
309 : * @q: request queue pointer
310 : */
311 0 : void blk_set_pm_only(struct request_queue *q)
312 : {
313 0 : atomic_inc(&q->pm_only);
314 0 : }
315 : EXPORT_SYMBOL_GPL(blk_set_pm_only);
316 :
317 0 : void blk_clear_pm_only(struct request_queue *q)
318 : {
319 0 : int pm_only;
320 :
321 0 : pm_only = atomic_dec_return(&q->pm_only);
322 0 : WARN_ON_ONCE(pm_only < 0);
323 0 : if (pm_only == 0)
324 0 : wake_up_all(&q->mq_freeze_wq);
325 0 : }
326 : EXPORT_SYMBOL_GPL(blk_clear_pm_only);
327 :
328 : /**
329 : * blk_put_queue - decrement the request_queue refcount
330 : * @q: the request_queue structure to decrement the refcount for
331 : *
332 : * Decrements the refcount of the request_queue kobject. When this reaches 0
333 : * we'll have blk_release_queue() called.
334 : *
335 : * Context: Any context, but the last reference must not be dropped from
336 : * atomic context.
337 : */
338 0 : void blk_put_queue(struct request_queue *q)
339 : {
340 0 : kobject_put(&q->kobj);
341 0 : }
342 : EXPORT_SYMBOL(blk_put_queue);
343 :
344 0 : void blk_set_queue_dying(struct request_queue *q)
345 : {
346 0 : blk_queue_flag_set(QUEUE_FLAG_DYING, q);
347 :
348 : /*
349 : * When queue DYING flag is set, we need to block new req
350 : * entering queue, so we call blk_freeze_queue_start() to
351 : * prevent I/O from crossing blk_queue_enter().
352 : */
353 0 : blk_freeze_queue_start(q);
354 :
355 0 : if (queue_is_mq(q))
356 0 : blk_mq_wake_waiters(q);
357 :
358 : /* Make blk_queue_enter() reexamine the DYING flag. */
359 0 : wake_up_all(&q->mq_freeze_wq);
360 0 : }
361 : EXPORT_SYMBOL_GPL(blk_set_queue_dying);
362 :
363 : /**
364 : * blk_cleanup_queue - shutdown a request queue
365 : * @q: request queue to shutdown
366 : *
367 : * Mark @q DYING, drain all pending requests, mark @q DEAD, destroy and
368 : * put it. All future requests will be failed immediately with -ENODEV.
369 : *
370 : * Context: can sleep
371 : */
372 0 : void blk_cleanup_queue(struct request_queue *q)
373 : {
374 : /* cannot be called from atomic context */
375 0 : might_sleep();
376 :
377 0 : WARN_ON_ONCE(blk_queue_registered(q));
378 :
379 : /* mark @q DYING, no new request or merges will be allowed afterwards */
380 0 : blk_set_queue_dying(q);
381 :
382 0 : blk_queue_flag_set(QUEUE_FLAG_NOMERGES, q);
383 0 : blk_queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
384 :
385 : /*
386 : * Drain all requests queued before DYING marking. Set DEAD flag to
387 : * prevent that blk_mq_run_hw_queues() accesses the hardware queues
388 : * after draining finished.
389 : */
390 0 : blk_freeze_queue(q);
391 :
392 0 : rq_qos_exit(q);
393 :
394 0 : blk_queue_flag_set(QUEUE_FLAG_DEAD, q);
395 :
396 : /* for synchronous bio-based driver finish in-flight integrity i/o */
397 0 : blk_flush_integrity();
398 :
399 : /* @q won't process any more request, flush async actions */
400 0 : del_timer_sync(&q->backing_dev_info->laptop_mode_wb_timer);
401 0 : blk_sync_queue(q);
402 :
403 0 : if (queue_is_mq(q))
404 0 : blk_mq_exit_queue(q);
405 :
406 : /*
407 : * In theory, request pool of sched_tags belongs to request queue.
408 : * However, the current implementation requires tag_set for freeing
409 : * requests, so free the pool now.
410 : *
411 : * Queue has become frozen, there can't be any in-queue requests, so
412 : * it is safe to free requests now.
413 : */
414 0 : mutex_lock(&q->sysfs_lock);
415 0 : if (q->elevator)
416 0 : blk_mq_sched_free_requests(q);
417 0 : mutex_unlock(&q->sysfs_lock);
418 :
419 0 : percpu_ref_exit(&q->q_usage_counter);
420 :
421 : /* @q is and will stay empty, shutdown and put */
422 0 : blk_put_queue(q);
423 0 : }
424 : EXPORT_SYMBOL(blk_cleanup_queue);
425 :
426 : /**
427 : * blk_queue_enter() - try to increase q->q_usage_counter
428 : * @q: request queue pointer
429 : * @flags: BLK_MQ_REQ_NOWAIT and/or BLK_MQ_REQ_PM
430 : */
431 8738 : int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags)
432 : {
433 8738 : const bool pm = flags & BLK_MQ_REQ_PM;
434 :
435 8738 : while (true) {
436 8738 : bool success = false;
437 :
438 8738 : rcu_read_lock();
439 8738 : if (percpu_ref_tryget_live(&q->q_usage_counter)) {
440 : /*
441 : * The code that increments the pm_only counter is
442 : * responsible for ensuring that that counter is
443 : * globally visible before the queue is unfrozen.
444 : */
445 8738 : if ((pm && queue_rpm_status(q) != RPM_SUSPENDED) ||
446 8738 : !blk_queue_pm_only(q)) {
447 8738 : success = true;
448 : } else {
449 0 : percpu_ref_put(&q->q_usage_counter);
450 : }
451 : }
452 8738 : rcu_read_unlock();
453 :
454 0 : if (success)
455 8738 : return 0;
456 :
457 0 : if (flags & BLK_MQ_REQ_NOWAIT)
458 : return -EBUSY;
459 :
460 : /*
461 : * read pair of barrier in blk_freeze_queue_start(),
462 : * we need to order reading __PERCPU_REF_DEAD flag of
463 : * .q_usage_counter and reading .mq_freeze_depth or
464 : * queue dying flag, otherwise the following wait may
465 : * never return if the two reads are reordered.
466 : */
467 0 : smp_rmb();
468 :
469 0 : wait_event(q->mq_freeze_wq,
470 : (!q->mq_freeze_depth &&
471 : blk_pm_resume_queue(pm, q)) ||
472 : blk_queue_dying(q));
473 0 : if (blk_queue_dying(q))
474 : return -ENODEV;
475 : }
476 : }
477 :
478 8736 : static inline int bio_queue_enter(struct bio *bio)
479 : {
480 8736 : struct request_queue *q = bio->bi_bdev->bd_disk->queue;
481 8736 : bool nowait = bio->bi_opf & REQ_NOWAIT;
482 8736 : int ret;
483 :
484 8736 : ret = blk_queue_enter(q, nowait ? BLK_MQ_REQ_NOWAIT : 0);
485 8737 : if (unlikely(ret)) {
486 0 : if (nowait && !blk_queue_dying(q))
487 0 : bio_wouldblock_error(bio);
488 : else
489 0 : bio_io_error(bio);
490 : }
491 :
492 8737 : return ret;
493 : }
494 :
495 8755 : void blk_queue_exit(struct request_queue *q)
496 : {
497 8755 : percpu_ref_put(&q->q_usage_counter);
498 8755 : }
499 :
500 0 : static void blk_queue_usage_counter_release(struct percpu_ref *ref)
501 : {
502 0 : struct request_queue *q =
503 0 : container_of(ref, struct request_queue, q_usage_counter);
504 :
505 0 : wake_up_all(&q->mq_freeze_wq);
506 0 : }
507 :
508 8 : static void blk_rq_timed_out_timer(struct timer_list *t)
509 : {
510 8 : struct request_queue *q = from_timer(q, t, timeout);
511 :
512 8 : kblockd_schedule_work(&q->timeout_work);
513 8 : }
514 :
515 0 : static void blk_timeout_work(struct work_struct *work)
516 : {
517 0 : }
518 :
519 9 : struct request_queue *blk_alloc_queue(int node_id)
520 : {
521 9 : struct request_queue *q;
522 9 : int ret;
523 :
524 9 : q = kmem_cache_alloc_node(blk_requestq_cachep,
525 : GFP_KERNEL | __GFP_ZERO, node_id);
526 9 : if (!q)
527 : return NULL;
528 :
529 9 : q->last_merge = NULL;
530 :
531 9 : q->id = ida_simple_get(&blk_queue_ida, 0, 0, GFP_KERNEL);
532 9 : if (q->id < 0)
533 0 : goto fail_q;
534 :
535 9 : ret = bioset_init(&q->bio_split, BIO_POOL_SIZE, 0, 0);
536 9 : if (ret)
537 0 : goto fail_id;
538 :
539 9 : q->backing_dev_info = bdi_alloc(node_id);
540 9 : if (!q->backing_dev_info)
541 0 : goto fail_split;
542 :
543 9 : q->stats = blk_alloc_queue_stats();
544 9 : if (!q->stats)
545 0 : goto fail_stats;
546 :
547 9 : q->node = node_id;
548 :
549 9 : atomic_set(&q->nr_active_requests_shared_sbitmap, 0);
550 :
551 9 : timer_setup(&q->backing_dev_info->laptop_mode_wb_timer,
552 : laptop_mode_timer_fn, 0);
553 9 : timer_setup(&q->timeout, blk_rq_timed_out_timer, 0);
554 9 : INIT_WORK(&q->timeout_work, blk_timeout_work);
555 9 : INIT_LIST_HEAD(&q->icq_list);
556 : #ifdef CONFIG_BLK_CGROUP
557 : INIT_LIST_HEAD(&q->blkg_list);
558 : #endif
559 :
560 9 : kobject_init(&q->kobj, &blk_queue_ktype);
561 :
562 9 : mutex_init(&q->debugfs_mutex);
563 9 : mutex_init(&q->sysfs_lock);
564 9 : mutex_init(&q->sysfs_dir_lock);
565 9 : spin_lock_init(&q->queue_lock);
566 :
567 9 : init_waitqueue_head(&q->mq_freeze_wq);
568 9 : mutex_init(&q->mq_freeze_lock);
569 :
570 : /*
571 : * Init percpu_ref in atomic mode so that it's faster to shutdown.
572 : * See blk_register_queue() for details.
573 : */
574 9 : if (percpu_ref_init(&q->q_usage_counter,
575 : blk_queue_usage_counter_release,
576 : PERCPU_REF_INIT_ATOMIC, GFP_KERNEL))
577 0 : goto fail_bdi;
578 :
579 9 : if (blkcg_init_queue(q))
580 : goto fail_ref;
581 :
582 9 : blk_queue_dma_alignment(q, 511);
583 9 : blk_set_default_limits(&q->limits);
584 9 : q->nr_requests = BLKDEV_MAX_RQ;
585 :
586 9 : return q;
587 :
588 : fail_ref:
589 : percpu_ref_exit(&q->q_usage_counter);
590 0 : fail_bdi:
591 0 : blk_free_queue_stats(q->stats);
592 0 : fail_stats:
593 0 : bdi_put(q->backing_dev_info);
594 0 : fail_split:
595 0 : bioset_exit(&q->bio_split);
596 0 : fail_id:
597 0 : ida_simple_remove(&blk_queue_ida, q->id);
598 0 : fail_q:
599 0 : kmem_cache_free(blk_requestq_cachep, q);
600 0 : return NULL;
601 : }
602 : EXPORT_SYMBOL(blk_alloc_queue);
603 :
604 : /**
605 : * blk_get_queue - increment the request_queue refcount
606 : * @q: the request_queue structure to increment the refcount for
607 : *
608 : * Increment the refcount of the request_queue kobject.
609 : *
610 : * Context: Any context.
611 : */
612 9 : bool blk_get_queue(struct request_queue *q)
613 : {
614 9 : if (likely(!blk_queue_dying(q))) {
615 9 : __blk_get_queue(q);
616 9 : return true;
617 : }
618 :
619 : return false;
620 : }
621 : EXPORT_SYMBOL(blk_get_queue);
622 :
623 : /**
624 : * blk_get_request - allocate a request
625 : * @q: request queue to allocate a request for
626 : * @op: operation (REQ_OP_*) and REQ_* flags, e.g. REQ_SYNC.
627 : * @flags: BLK_MQ_REQ_* flags, e.g. BLK_MQ_REQ_NOWAIT.
628 : */
629 2 : struct request *blk_get_request(struct request_queue *q, unsigned int op,
630 : blk_mq_req_flags_t flags)
631 : {
632 2 : struct request *req;
633 :
634 2 : WARN_ON_ONCE(op & REQ_NOWAIT);
635 2 : WARN_ON_ONCE(flags & ~(BLK_MQ_REQ_NOWAIT | BLK_MQ_REQ_PM));
636 :
637 2 : req = blk_mq_alloc_request(q, op, flags);
638 2 : if (!IS_ERR(req) && q->mq_ops->initialize_rq_fn)
639 0 : q->mq_ops->initialize_rq_fn(req);
640 :
641 2 : return req;
642 : }
643 : EXPORT_SYMBOL(blk_get_request);
644 :
645 2 : void blk_put_request(struct request *req)
646 : {
647 2 : blk_mq_free_request(req);
648 2 : }
649 : EXPORT_SYMBOL(blk_put_request);
650 :
651 0 : static void handle_bad_sector(struct bio *bio, sector_t maxsector)
652 : {
653 0 : char b[BDEVNAME_SIZE];
654 :
655 0 : pr_info_ratelimited("attempt to access beyond end of device\n"
656 : "%s: rw=%d, want=%llu, limit=%llu\n",
657 : bio_devname(bio, b), bio->bi_opf,
658 : bio_end_sector(bio), maxsector);
659 0 : }
660 :
661 : #ifdef CONFIG_FAIL_MAKE_REQUEST
662 :
663 : static DECLARE_FAULT_ATTR(fail_make_request);
664 :
665 : static int __init setup_fail_make_request(char *str)
666 : {
667 : return setup_fault_attr(&fail_make_request, str);
668 : }
669 : __setup("fail_make_request=", setup_fail_make_request);
670 :
671 : static bool should_fail_request(struct block_device *part, unsigned int bytes)
672 : {
673 : return part->bd_make_it_fail && should_fail(&fail_make_request, bytes);
674 : }
675 :
676 : static int __init fail_make_request_debugfs(void)
677 : {
678 : struct dentry *dir = fault_create_debugfs_attr("fail_make_request",
679 : NULL, &fail_make_request);
680 :
681 : return PTR_ERR_OR_ZERO(dir);
682 : }
683 :
684 : late_initcall(fail_make_request_debugfs);
685 :
686 : #else /* CONFIG_FAIL_MAKE_REQUEST */
687 :
688 17423 : static inline bool should_fail_request(struct block_device *part,
689 : unsigned int bytes)
690 : {
691 17423 : return false;
692 : }
693 :
694 : #endif /* CONFIG_FAIL_MAKE_REQUEST */
695 :
696 8737 : static inline bool bio_check_ro(struct bio *bio)
697 : {
698 8737 : if (op_is_write(bio_op(bio)) && bdev_read_only(bio->bi_bdev)) {
699 0 : char b[BDEVNAME_SIZE];
700 :
701 0 : if (op_is_flush(bio->bi_opf) && !bio_sectors(bio))
702 : return false;
703 :
704 0 : WARN_ONCE(1,
705 : "Trying to write to read-only block-device %s (partno %d)\n",
706 : bio_devname(bio, b), bio->bi_bdev->bd_partno);
707 : /* Older lvm-tools actually trigger this */
708 0 : return false;
709 : }
710 :
711 : return false;
712 : }
713 :
714 8736 : static noinline int should_fail_bio(struct bio *bio)
715 : {
716 8736 : if (should_fail_request(bdev_whole(bio->bi_bdev), bio->bi_iter.bi_size))
717 : return -EIO;
718 8736 : return 0;
719 : }
720 : ALLOW_ERROR_INJECTION(should_fail_bio, ERRNO);
721 :
722 : /*
723 : * Check whether this bio extends beyond the end of the device or partition.
724 : * This may well happen - the kernel calls bread() without checking the size of
725 : * the device, e.g., when mounting a file system.
726 : */
727 8737 : static inline int bio_check_eod(struct bio *bio)
728 : {
729 8737 : sector_t maxsector = bdev_nr_sectors(bio->bi_bdev);
730 8737 : unsigned int nr_sectors = bio_sectors(bio);
731 :
732 8737 : if (nr_sectors && maxsector &&
733 8665 : (nr_sectors > maxsector ||
734 8665 : bio->bi_iter.bi_sector > maxsector - nr_sectors)) {
735 0 : handle_bad_sector(bio, maxsector);
736 0 : return -EIO;
737 : }
738 : return 0;
739 : }
740 :
741 : /*
742 : * Remap block n of partition p to block n+start(p) of the disk.
743 : */
744 8687 : static int blk_partition_remap(struct bio *bio)
745 : {
746 8687 : struct block_device *p = bio->bi_bdev;
747 :
748 8687 : if (unlikely(should_fail_request(p, bio->bi_iter.bi_size)))
749 : return -EIO;
750 8687 : if (bio_sectors(bio)) {
751 8614 : bio->bi_iter.bi_sector += p->bd_start_sect;
752 8614 : trace_block_bio_remap(bio, p->bd_dev,
753 : bio->bi_iter.bi_sector -
754 8614 : p->bd_start_sect);
755 : }
756 8689 : bio_set_flag(bio, BIO_REMAPPED);
757 8689 : return 0;
758 : }
759 :
760 : /*
761 : * Check write append to a zoned block device.
762 : */
763 0 : static inline blk_status_t blk_check_zone_append(struct request_queue *q,
764 : struct bio *bio)
765 : {
766 0 : sector_t pos = bio->bi_iter.bi_sector;
767 0 : int nr_sectors = bio_sectors(bio);
768 :
769 : /* Only applicable to zoned block devices */
770 0 : if (!blk_queue_is_zoned(q))
771 0 : return BLK_STS_NOTSUPP;
772 :
773 : /* The bio sector must point to the start of a sequential zone */
774 : if (pos & (blk_queue_zone_sectors(q) - 1) ||
775 : !blk_queue_zone_is_seq(q, pos))
776 : return BLK_STS_IOERR;
777 :
778 : /*
779 : * Not allowed to cross zone boundaries. Otherwise, the BIO will be
780 : * split and could result in non-contiguous sectors being written in
781 : * different zones.
782 : */
783 : if (nr_sectors > q->limits.chunk_sectors)
784 : return BLK_STS_IOERR;
785 :
786 : /* Make sure the BIO is small enough and will not get split */
787 : if (nr_sectors > q->limits.max_zone_append_sectors)
788 : return BLK_STS_IOERR;
789 :
790 : bio->bi_opf |= REQ_NOMERGE;
791 :
792 : return BLK_STS_OK;
793 : }
794 :
795 8737 : static noinline_for_stack bool submit_bio_checks(struct bio *bio)
796 : {
797 8737 : struct block_device *bdev = bio->bi_bdev;
798 8737 : struct request_queue *q = bdev->bd_disk->queue;
799 8737 : blk_status_t status = BLK_STS_IOERR;
800 8737 : struct blk_plug *plug;
801 :
802 8737 : might_sleep();
803 :
804 8737 : plug = blk_mq_plug(q, bio);
805 8737 : if (plug && plug->nowait)
806 0 : bio->bi_opf |= REQ_NOWAIT;
807 :
808 : /*
809 : * For a REQ_NOWAIT based request, return -EOPNOTSUPP
810 : * if queue does not support NOWAIT.
811 : */
812 8737 : if ((bio->bi_opf & REQ_NOWAIT) && !blk_queue_nowait(q))
813 0 : goto not_supported;
814 :
815 8737 : if (should_fail_bio(bio))
816 0 : goto end_io;
817 8737 : if (unlikely(bio_check_ro(bio)))
818 0 : goto end_io;
819 8737 : if (!bio_flagged(bio, BIO_REMAPPED)) {
820 8737 : if (unlikely(bio_check_eod(bio)))
821 0 : goto end_io;
822 8737 : if (bdev->bd_partno && unlikely(blk_partition_remap(bio)))
823 0 : goto end_io;
824 : }
825 :
826 : /*
827 : * Filter flush bio's early so that bio based drivers without flush
828 : * support don't have to worry about them.
829 : */
830 8737 : if (op_is_flush(bio->bi_opf) &&
831 132 : !test_bit(QUEUE_FLAG_WC, &q->queue_flags)) {
832 0 : bio->bi_opf &= ~(REQ_PREFLUSH | REQ_FUA);
833 0 : if (!bio_sectors(bio)) {
834 0 : status = BLK_STS_OK;
835 0 : goto end_io;
836 : }
837 : }
838 :
839 8737 : if (!test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
840 8737 : bio->bi_opf &= ~REQ_HIPRI;
841 :
842 8737 : switch (bio_op(bio)) {
843 0 : case REQ_OP_DISCARD:
844 0 : if (!blk_queue_discard(q))
845 0 : goto not_supported;
846 : break;
847 0 : case REQ_OP_SECURE_ERASE:
848 0 : if (!blk_queue_secure_erase(q))
849 0 : goto not_supported;
850 : break;
851 0 : case REQ_OP_WRITE_SAME:
852 0 : if (!q->limits.max_write_same_sectors)
853 0 : goto not_supported;
854 : break;
855 : case REQ_OP_ZONE_APPEND:
856 0 : status = blk_check_zone_append(q, bio);
857 0 : if (status != BLK_STS_OK)
858 0 : goto end_io;
859 : break;
860 : case REQ_OP_ZONE_RESET:
861 : case REQ_OP_ZONE_OPEN:
862 : case REQ_OP_ZONE_CLOSE:
863 : case REQ_OP_ZONE_FINISH:
864 0 : if (!blk_queue_is_zoned(q))
865 0 : goto not_supported;
866 : break;
867 : case REQ_OP_ZONE_RESET_ALL:
868 0 : if (!blk_queue_is_zoned(q) || !blk_queue_zone_resetall(q))
869 0 : goto not_supported;
870 : break;
871 0 : case REQ_OP_WRITE_ZEROES:
872 0 : if (!q->limits.max_write_zeroes_sectors)
873 0 : goto not_supported;
874 : break;
875 : default:
876 : break;
877 : }
878 :
879 : /*
880 : * Various block parts want %current->io_context, so allocate it up
881 : * front rather than dealing with lots of pain to allocate it only
882 : * where needed. This may fail and the block layer knows how to live
883 : * with it.
884 : */
885 8737 : if (unlikely(!current->io_context))
886 145 : create_task_io_context(current, GFP_ATOMIC, q->node);
887 :
888 8737 : if (blk_throtl_bio(bio)) {
889 : blkcg_bio_issue_init(bio);
890 : return false;
891 : }
892 :
893 8737 : blk_cgroup_bio_start(bio);
894 8737 : blkcg_bio_issue_init(bio);
895 :
896 8737 : if (!bio_flagged(bio, BIO_TRACE_COMPLETION)) {
897 8737 : trace_block_bio_queue(bio);
898 : /* Now that enqueuing has been traced, we need to trace
899 : * completion as well.
900 : */
901 8735 : bio_set_flag(bio, BIO_TRACE_COMPLETION);
902 : }
903 : return true;
904 :
905 : not_supported:
906 : status = BLK_STS_NOTSUPP;
907 0 : end_io:
908 0 : bio->bi_status = status;
909 0 : bio_endio(bio);
910 0 : return false;
911 : }
912 :
913 0 : static blk_qc_t __submit_bio(struct bio *bio)
914 : {
915 0 : struct gendisk *disk = bio->bi_bdev->bd_disk;
916 0 : blk_qc_t ret = BLK_QC_T_NONE;
917 :
918 0 : if (blk_crypto_bio_prep(&bio)) {
919 0 : if (!disk->fops->submit_bio)
920 0 : return blk_mq_submit_bio(bio);
921 0 : ret = disk->fops->submit_bio(bio);
922 : }
923 0 : blk_queue_exit(disk->queue);
924 0 : return ret;
925 : }
926 :
927 : /*
928 : * The loop in this function may be a bit non-obvious, and so deserves some
929 : * explanation:
930 : *
931 : * - Before entering the loop, bio->bi_next is NULL (as all callers ensure
932 : * that), so we have a list with a single bio.
933 : * - We pretend that we have just taken it off a longer list, so we assign
934 : * bio_list to a pointer to the bio_list_on_stack, thus initialising the
935 : * bio_list of new bios to be added. ->submit_bio() may indeed add some more
936 : * bios through a recursive call to submit_bio_noacct. If it did, we find a
937 : * non-NULL value in bio_list and re-enter the loop from the top.
938 : * - In this case we really did just take the bio of the top of the list (no
939 : * pretending) and so remove it from bio_list, and call into ->submit_bio()
940 : * again.
941 : *
942 : * bio_list_on_stack[0] contains bios submitted by the current ->submit_bio.
943 : * bio_list_on_stack[1] contains bios that were submitted before the current
944 : * ->submit_bio_bio, but that haven't been processed yet.
945 : */
946 0 : static blk_qc_t __submit_bio_noacct(struct bio *bio)
947 : {
948 0 : struct bio_list bio_list_on_stack[2];
949 0 : blk_qc_t ret = BLK_QC_T_NONE;
950 :
951 0 : BUG_ON(bio->bi_next);
952 :
953 0 : bio_list_init(&bio_list_on_stack[0]);
954 0 : current->bio_list = bio_list_on_stack;
955 :
956 0 : do {
957 0 : struct request_queue *q = bio->bi_bdev->bd_disk->queue;
958 0 : struct bio_list lower, same;
959 :
960 0 : if (unlikely(bio_queue_enter(bio) != 0))
961 0 : continue;
962 :
963 : /*
964 : * Create a fresh bio_list for all subordinate requests.
965 : */
966 0 : bio_list_on_stack[1] = bio_list_on_stack[0];
967 0 : bio_list_init(&bio_list_on_stack[0]);
968 :
969 0 : ret = __submit_bio(bio);
970 :
971 : /*
972 : * Sort new bios into those for a lower level and those for the
973 : * same level.
974 : */
975 0 : bio_list_init(&lower);
976 0 : bio_list_init(&same);
977 0 : while ((bio = bio_list_pop(&bio_list_on_stack[0])) != NULL)
978 0 : if (q == bio->bi_bdev->bd_disk->queue)
979 0 : bio_list_add(&same, bio);
980 : else
981 0 : bio_list_add(&lower, bio);
982 :
983 : /*
984 : * Now assemble so we handle the lowest level first.
985 : */
986 0 : bio_list_merge(&bio_list_on_stack[0], &lower);
987 0 : bio_list_merge(&bio_list_on_stack[0], &same);
988 0 : bio_list_merge(&bio_list_on_stack[0], &bio_list_on_stack[1]);
989 0 : } while ((bio = bio_list_pop(&bio_list_on_stack[0])));
990 :
991 0 : current->bio_list = NULL;
992 0 : return ret;
993 : }
994 :
995 8736 : static blk_qc_t __submit_bio_noacct_mq(struct bio *bio)
996 : {
997 8736 : struct bio_list bio_list[2] = { };
998 8736 : blk_qc_t ret = BLK_QC_T_NONE;
999 :
1000 8736 : current->bio_list = bio_list;
1001 :
1002 8736 : do {
1003 8736 : struct gendisk *disk = bio->bi_bdev->bd_disk;
1004 :
1005 8736 : if (unlikely(bio_queue_enter(bio) != 0))
1006 0 : continue;
1007 :
1008 8737 : if (!blk_crypto_bio_prep(&bio)) {
1009 : blk_queue_exit(disk->queue);
1010 : ret = BLK_QC_T_NONE;
1011 : continue;
1012 : }
1013 :
1014 8737 : ret = blk_mq_submit_bio(bio);
1015 8737 : } while ((bio = bio_list_pop(&bio_list[0])));
1016 :
1017 8737 : current->bio_list = NULL;
1018 8737 : return ret;
1019 : }
1020 :
1021 : /**
1022 : * submit_bio_noacct - re-submit a bio to the block device layer for I/O
1023 : * @bio: The bio describing the location in memory and on the device.
1024 : *
1025 : * This is a version of submit_bio() that shall only be used for I/O that is
1026 : * resubmitted to lower level drivers by stacking block drivers. All file
1027 : * systems and other upper level users of the block layer should use
1028 : * submit_bio() instead.
1029 : */
1030 8737 : blk_qc_t submit_bio_noacct(struct bio *bio)
1031 : {
1032 8737 : if (!submit_bio_checks(bio))
1033 : return BLK_QC_T_NONE;
1034 :
1035 : /*
1036 : * We only want one ->submit_bio to be active at a time, else stack
1037 : * usage with stacked devices could be a problem. Use current->bio_list
1038 : * to collect a list of requests submited by a ->submit_bio method while
1039 : * it is active, and then process them after it returned.
1040 : */
1041 8736 : if (current->bio_list) {
1042 0 : bio_list_add(¤t->bio_list[0], bio);
1043 0 : return BLK_QC_T_NONE;
1044 : }
1045 :
1046 8736 : if (!bio->bi_bdev->bd_disk->fops->submit_bio)
1047 8736 : return __submit_bio_noacct_mq(bio);
1048 0 : return __submit_bio_noacct(bio);
1049 : }
1050 : EXPORT_SYMBOL(submit_bio_noacct);
1051 :
1052 : /**
1053 : * submit_bio - submit a bio to the block device layer for I/O
1054 : * @bio: The &struct bio which describes the I/O
1055 : *
1056 : * submit_bio() is used to submit I/O requests to block devices. It is passed a
1057 : * fully set up &struct bio that describes the I/O that needs to be done. The
1058 : * bio will be send to the device described by the bi_bdev field.
1059 : *
1060 : * The success/failure status of the request, along with notification of
1061 : * completion, is delivered asynchronously through the ->bi_end_io() callback
1062 : * in @bio. The bio must NOT be touched by thecaller until ->bi_end_io() has
1063 : * been called.
1064 : */
1065 8737 : blk_qc_t submit_bio(struct bio *bio)
1066 : {
1067 8737 : if (blkcg_punt_bio_submit(bio))
1068 : return BLK_QC_T_NONE;
1069 :
1070 : /*
1071 : * If it's a regular read/write or a barrier with data attached,
1072 : * go through the normal accounting stuff before submission.
1073 : */
1074 8737 : if (bio_has_data(bio)) {
1075 8665 : unsigned int count;
1076 :
1077 8665 : if (unlikely(bio_op(bio) == REQ_OP_WRITE_SAME))
1078 0 : count = queue_logical_block_size(
1079 0 : bio->bi_bdev->bd_disk->queue) >> 9;
1080 : else
1081 8665 : count = bio_sectors(bio);
1082 :
1083 8665 : if (op_is_write(bio_op(bio))) {
1084 3003 : count_vm_events(PGPGOUT, count);
1085 : } else {
1086 5662 : task_io_account_read(bio->bi_iter.bi_size);
1087 5662 : count_vm_events(PGPGIN, count);
1088 : }
1089 :
1090 8665 : if (unlikely(block_dump)) {
1091 0 : char b[BDEVNAME_SIZE];
1092 0 : printk(KERN_DEBUG "%s(%d): %s block %Lu on %s (%u sectors)\n",
1093 0 : current->comm, task_pid_nr(current),
1094 0 : op_is_write(bio_op(bio)) ? "WRITE" : "READ",
1095 0 : (unsigned long long)bio->bi_iter.bi_sector,
1096 : bio_devname(bio, b), count);
1097 : }
1098 : }
1099 :
1100 : /*
1101 : * If we're reading data that is part of the userspace workingset, count
1102 : * submission time as memory stall. When the device is congested, or
1103 : * the submitting cgroup IO-throttled, submission can be a significant
1104 : * part of overall IO time.
1105 : */
1106 8737 : if (unlikely(bio_op(bio) == REQ_OP_READ &&
1107 : bio_flagged(bio, BIO_WORKINGSET))) {
1108 0 : unsigned long pflags;
1109 0 : blk_qc_t ret;
1110 :
1111 0 : psi_memstall_enter(&pflags);
1112 0 : ret = submit_bio_noacct(bio);
1113 0 : psi_memstall_leave(&pflags);
1114 :
1115 0 : return ret;
1116 : }
1117 :
1118 8737 : return submit_bio_noacct(bio);
1119 : }
1120 : EXPORT_SYMBOL(submit_bio);
1121 :
1122 : /**
1123 : * blk_cloned_rq_check_limits - Helper function to check a cloned request
1124 : * for the new queue limits
1125 : * @q: the queue
1126 : * @rq: the request being checked
1127 : *
1128 : * Description:
1129 : * @rq may have been made based on weaker limitations of upper-level queues
1130 : * in request stacking drivers, and it may violate the limitation of @q.
1131 : * Since the block layer and the underlying device driver trust @rq
1132 : * after it is inserted to @q, it should be checked against @q before
1133 : * the insertion using this generic function.
1134 : *
1135 : * Request stacking drivers like request-based dm may change the queue
1136 : * limits when retrying requests on other queues. Those requests need
1137 : * to be checked against the new queue limits again during dispatch.
1138 : */
1139 0 : static blk_status_t blk_cloned_rq_check_limits(struct request_queue *q,
1140 : struct request *rq)
1141 : {
1142 0 : unsigned int max_sectors = blk_queue_get_max_sectors(q, req_op(rq));
1143 :
1144 0 : if (blk_rq_sectors(rq) > max_sectors) {
1145 : /*
1146 : * SCSI device does not have a good way to return if
1147 : * Write Same/Zero is actually supported. If a device rejects
1148 : * a non-read/write command (discard, write same,etc.) the
1149 : * low-level device driver will set the relevant queue limit to
1150 : * 0 to prevent blk-lib from issuing more of the offending
1151 : * operations. Commands queued prior to the queue limit being
1152 : * reset need to be completed with BLK_STS_NOTSUPP to avoid I/O
1153 : * errors being propagated to upper layers.
1154 : */
1155 0 : if (max_sectors == 0)
1156 : return BLK_STS_NOTSUPP;
1157 :
1158 0 : printk(KERN_ERR "%s: over max size limit. (%u > %u)\n",
1159 : __func__, blk_rq_sectors(rq), max_sectors);
1160 0 : return BLK_STS_IOERR;
1161 : }
1162 :
1163 : /*
1164 : * queue's settings related to segment counting like q->bounce_pfn
1165 : * may differ from that of other stacking queues.
1166 : * Recalculate it to check the request correctly on this queue's
1167 : * limitation.
1168 : */
1169 0 : rq->nr_phys_segments = blk_recalc_rq_segments(rq);
1170 0 : if (rq->nr_phys_segments > queue_max_segments(q)) {
1171 0 : printk(KERN_ERR "%s: over max segments limit. (%hu > %hu)\n",
1172 0 : __func__, rq->nr_phys_segments, queue_max_segments(q));
1173 0 : return BLK_STS_IOERR;
1174 : }
1175 :
1176 : return BLK_STS_OK;
1177 : }
1178 :
1179 : /**
1180 : * blk_insert_cloned_request - Helper for stacking drivers to submit a request
1181 : * @q: the queue to submit the request
1182 : * @rq: the request being queued
1183 : */
1184 0 : blk_status_t blk_insert_cloned_request(struct request_queue *q, struct request *rq)
1185 : {
1186 0 : blk_status_t ret;
1187 :
1188 0 : ret = blk_cloned_rq_check_limits(q, rq);
1189 0 : if (ret != BLK_STS_OK)
1190 : return ret;
1191 :
1192 0 : if (rq->rq_disk &&
1193 : should_fail_request(rq->rq_disk->part0, blk_rq_bytes(rq)))
1194 : return BLK_STS_IOERR;
1195 :
1196 0 : if (blk_crypto_insert_cloned_request(rq))
1197 : return BLK_STS_IOERR;
1198 :
1199 0 : if (blk_queue_io_stat(q))
1200 0 : blk_account_io_start(rq);
1201 :
1202 : /*
1203 : * Since we have a scheduler attached on the top device,
1204 : * bypass a potential scheduler on the bottom device for
1205 : * insert.
1206 : */
1207 0 : return blk_mq_request_issue_directly(rq, true);
1208 : }
1209 : EXPORT_SYMBOL_GPL(blk_insert_cloned_request);
1210 :
1211 : /**
1212 : * blk_rq_err_bytes - determine number of bytes till the next failure boundary
1213 : * @rq: request to examine
1214 : *
1215 : * Description:
1216 : * A request could be merge of IOs which require different failure
1217 : * handling. This function determines the number of bytes which
1218 : * can be failed from the beginning of the request without
1219 : * crossing into area which need to be retried further.
1220 : *
1221 : * Return:
1222 : * The number of bytes to fail.
1223 : */
1224 0 : unsigned int blk_rq_err_bytes(const struct request *rq)
1225 : {
1226 0 : unsigned int ff = rq->cmd_flags & REQ_FAILFAST_MASK;
1227 0 : unsigned int bytes = 0;
1228 0 : struct bio *bio;
1229 :
1230 0 : if (!(rq->rq_flags & RQF_MIXED_MERGE))
1231 0 : return blk_rq_bytes(rq);
1232 :
1233 : /*
1234 : * Currently the only 'mixing' which can happen is between
1235 : * different fastfail types. We can safely fail portions
1236 : * which have all the failfast bits that the first one has -
1237 : * the ones which are at least as eager to fail as the first
1238 : * one.
1239 : */
1240 0 : for (bio = rq->bio; bio; bio = bio->bi_next) {
1241 0 : if ((bio->bi_opf & ff) != ff)
1242 : break;
1243 0 : bytes += bio->bi_iter.bi_size;
1244 : }
1245 :
1246 : /* this could lead to infinite loop */
1247 0 : BUG_ON(blk_rq_bytes(rq) && !bytes);
1248 : return bytes;
1249 : }
1250 : EXPORT_SYMBOL_GPL(blk_rq_err_bytes);
1251 :
1252 6507 : static void update_io_ticks(struct block_device *part, unsigned long now,
1253 : bool end)
1254 : {
1255 12912 : unsigned long stamp;
1256 12912 : again:
1257 12912 : stamp = READ_ONCE(part->bd_stamp);
1258 12912 : if (unlikely(stamp != now)) {
1259 2682 : if (likely(cmpxchg(&part->bd_stamp, stamp, now) == stamp))
1260 12912 : __part_stat_add(part, io_ticks, end ? now - stamp : 1);
1261 : }
1262 12912 : if (part->bd_partno) {
1263 6405 : part = bdev_whole(part);
1264 6405 : goto again;
1265 : }
1266 6507 : }
1267 :
1268 3314 : static void blk_account_io_completion(struct request *req, unsigned int bytes)
1269 : {
1270 6628 : if (req->part && blk_do_io_stat(req)) {
1271 3314 : const int sgrp = op_stat_group(req_op(req));
1272 :
1273 3314 : part_stat_lock();
1274 3314 : part_stat_add(req->part, sectors[sgrp], bytes >> 9);
1275 3314 : part_stat_unlock();
1276 : }
1277 3314 : }
1278 :
1279 3505 : void blk_account_io_done(struct request *req, u64 now)
1280 : {
1281 : /*
1282 : * Account IO completion. flush_rq isn't accounted as a
1283 : * normal IO on queueing nor completion. Accounting the
1284 : * containing request is enough.
1285 : */
1286 6819 : if (req->part && blk_do_io_stat(req) &&
1287 3314 : !(req->rq_flags & RQF_FLUSH_SEQ)) {
1288 3254 : const int sgrp = op_stat_group(req_op(req));
1289 :
1290 3254 : part_stat_lock();
1291 3254 : update_io_ticks(req->part, jiffies, true);
1292 3254 : part_stat_inc(req->part, ios[sgrp]);
1293 3254 : part_stat_add(req->part, nsecs[sgrp], now - req->start_time_ns);
1294 3254 : part_stat_unlock();
1295 : }
1296 3505 : }
1297 :
1298 3253 : void blk_account_io_start(struct request *rq)
1299 : {
1300 6506 : if (!blk_do_io_stat(rq))
1301 : return;
1302 :
1303 : /* passthrough requests can hold bios that do not have ->bi_bdev set */
1304 3253 : if (rq->bio && rq->bio->bi_bdev)
1305 3251 : rq->part = rq->bio->bi_bdev;
1306 : else
1307 2 : rq->part = rq->rq_disk->part0;
1308 :
1309 3253 : part_stat_lock();
1310 3253 : update_io_ticks(rq->part, jiffies, false);
1311 3254 : part_stat_unlock();
1312 : }
1313 :
1314 0 : static unsigned long __part_start_io_acct(struct block_device *part,
1315 : unsigned int sectors, unsigned int op)
1316 : {
1317 0 : const int sgrp = op_stat_group(op);
1318 0 : unsigned long now = READ_ONCE(jiffies);
1319 :
1320 0 : part_stat_lock();
1321 0 : update_io_ticks(part, now, false);
1322 0 : part_stat_inc(part, ios[sgrp]);
1323 0 : part_stat_add(part, sectors[sgrp], sectors);
1324 0 : part_stat_local_inc(part, in_flight[op_is_write(op)]);
1325 0 : part_stat_unlock();
1326 :
1327 0 : return now;
1328 : }
1329 :
1330 : /**
1331 : * bio_start_io_acct - start I/O accounting for bio based drivers
1332 : * @bio: bio to start account for
1333 : *
1334 : * Returns the start time that should be passed back to bio_end_io_acct().
1335 : */
1336 0 : unsigned long bio_start_io_acct(struct bio *bio)
1337 : {
1338 0 : return __part_start_io_acct(bio->bi_bdev, bio_sectors(bio), bio_op(bio));
1339 : }
1340 : EXPORT_SYMBOL_GPL(bio_start_io_acct);
1341 :
1342 0 : unsigned long disk_start_io_acct(struct gendisk *disk, unsigned int sectors,
1343 : unsigned int op)
1344 : {
1345 0 : return __part_start_io_acct(disk->part0, sectors, op);
1346 : }
1347 : EXPORT_SYMBOL(disk_start_io_acct);
1348 :
1349 0 : static void __part_end_io_acct(struct block_device *part, unsigned int op,
1350 : unsigned long start_time)
1351 : {
1352 0 : const int sgrp = op_stat_group(op);
1353 0 : unsigned long now = READ_ONCE(jiffies);
1354 0 : unsigned long duration = now - start_time;
1355 :
1356 0 : part_stat_lock();
1357 0 : update_io_ticks(part, now, true);
1358 0 : part_stat_add(part, nsecs[sgrp], jiffies_to_nsecs(duration));
1359 0 : part_stat_local_dec(part, in_flight[op_is_write(op)]);
1360 0 : part_stat_unlock();
1361 0 : }
1362 :
1363 0 : void bio_end_io_acct_remapped(struct bio *bio, unsigned long start_time,
1364 : struct block_device *orig_bdev)
1365 : {
1366 0 : __part_end_io_acct(orig_bdev, bio_op(bio), start_time);
1367 0 : }
1368 : EXPORT_SYMBOL_GPL(bio_end_io_acct_remapped);
1369 :
1370 0 : void disk_end_io_acct(struct gendisk *disk, unsigned int op,
1371 : unsigned long start_time)
1372 : {
1373 0 : __part_end_io_acct(disk->part0, op, start_time);
1374 0 : }
1375 : EXPORT_SYMBOL(disk_end_io_acct);
1376 :
1377 : /*
1378 : * Steal bios from a request and add them to a bio list.
1379 : * The request must not have been partially completed before.
1380 : */
1381 0 : void blk_steal_bios(struct bio_list *list, struct request *rq)
1382 : {
1383 0 : if (rq->bio) {
1384 0 : if (list->tail)
1385 0 : list->tail->bi_next = rq->bio;
1386 : else
1387 0 : list->head = rq->bio;
1388 0 : list->tail = rq->biotail;
1389 :
1390 0 : rq->bio = NULL;
1391 0 : rq->biotail = NULL;
1392 : }
1393 :
1394 0 : rq->__data_len = 0;
1395 0 : }
1396 : EXPORT_SYMBOL_GPL(blk_steal_bios);
1397 :
1398 : /**
1399 : * blk_update_request - Special helper function for request stacking drivers
1400 : * @req: the request being processed
1401 : * @error: block status code
1402 : * @nr_bytes: number of bytes to complete @req
1403 : *
1404 : * Description:
1405 : * Ends I/O on a number of bytes attached to @req, but doesn't complete
1406 : * the request structure even if @req doesn't have leftover.
1407 : * If @req has leftover, sets it up for the next range of segments.
1408 : *
1409 : * This special helper function is only for request stacking drivers
1410 : * (e.g. request-based dm) so that they can handle partial completion.
1411 : * Actual device drivers should use blk_mq_end_request instead.
1412 : *
1413 : * Passing the result of blk_rq_bytes() as @nr_bytes guarantees
1414 : * %false return from this function.
1415 : *
1416 : * Note:
1417 : * The RQF_SPECIAL_PAYLOAD flag is ignored on purpose in both
1418 : * blk_rq_bytes() and in blk_update_request().
1419 : *
1420 : * Return:
1421 : * %false - this request doesn't have any more data
1422 : * %true - this request has more data
1423 : **/
1424 3504 : bool blk_update_request(struct request *req, blk_status_t error,
1425 : unsigned int nr_bytes)
1426 : {
1427 3504 : int total_bytes;
1428 :
1429 3504 : trace_block_rq_complete(req, blk_status_to_errno(error), nr_bytes);
1430 :
1431 3505 : if (!req->bio)
1432 : return false;
1433 :
1434 : #ifdef CONFIG_BLK_DEV_INTEGRITY
1435 : if (blk_integrity_rq(req) && req_op(req) == REQ_OP_READ &&
1436 : error == BLK_STS_OK)
1437 : req->q->integrity.profile->complete_fn(req, nr_bytes);
1438 : #endif
1439 :
1440 3314 : if (unlikely(error && !blk_rq_is_passthrough(req) &&
1441 : !(req->rq_flags & RQF_QUIET)))
1442 0 : print_req_error(req, error, __func__);
1443 :
1444 3314 : blk_account_io_completion(req, nr_bytes);
1445 :
1446 3314 : total_bytes = 0;
1447 8799 : while (req->bio) {
1448 8799 : struct bio *bio = req->bio;
1449 8799 : unsigned bio_bytes = min(bio->bi_iter.bi_size, nr_bytes);
1450 :
1451 8799 : if (bio_bytes == bio->bi_iter.bi_size)
1452 8799 : req->bio = bio->bi_next;
1453 :
1454 : /* Completion has already been traced */
1455 8799 : bio_clear_flag(bio, BIO_TRACE_COMPLETION);
1456 8799 : req_bio_endio(req, bio, bio_bytes, error);
1457 :
1458 8799 : total_bytes += bio_bytes;
1459 8799 : nr_bytes -= bio_bytes;
1460 :
1461 8799 : if (!nr_bytes)
1462 : break;
1463 : }
1464 :
1465 : /*
1466 : * completely done
1467 : */
1468 3314 : if (!req->bio) {
1469 : /*
1470 : * Reset counters so that the request stacking driver
1471 : * can find how many bytes remain in the request
1472 : * later.
1473 : */
1474 3314 : req->__data_len = 0;
1475 3314 : return false;
1476 : }
1477 :
1478 0 : req->__data_len -= total_bytes;
1479 :
1480 : /* update sector only for requests with clear definition of sector */
1481 0 : if (!blk_rq_is_passthrough(req))
1482 0 : req->__sector += total_bytes >> 9;
1483 :
1484 : /* mixed attributes always follow the first bio */
1485 0 : if (req->rq_flags & RQF_MIXED_MERGE) {
1486 0 : req->cmd_flags &= ~REQ_FAILFAST_MASK;
1487 0 : req->cmd_flags |= req->bio->bi_opf & REQ_FAILFAST_MASK;
1488 : }
1489 :
1490 0 : if (!(req->rq_flags & RQF_SPECIAL_PAYLOAD)) {
1491 : /*
1492 : * If total number of sectors is less than the first segment
1493 : * size, something has gone terribly wrong.
1494 : */
1495 0 : if (blk_rq_bytes(req) < blk_rq_cur_bytes(req)) {
1496 0 : blk_dump_rq_flags(req, "request botched");
1497 0 : req->__data_len = blk_rq_cur_bytes(req);
1498 : }
1499 :
1500 : /* recalculate the number of segments */
1501 0 : req->nr_phys_segments = blk_recalc_rq_segments(req);
1502 : }
1503 :
1504 : return true;
1505 : }
1506 : EXPORT_SYMBOL_GPL(blk_update_request);
1507 :
1508 : #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
1509 : /**
1510 : * rq_flush_dcache_pages - Helper function to flush all pages in a request
1511 : * @rq: the request to be flushed
1512 : *
1513 : * Description:
1514 : * Flush all pages in @rq.
1515 : */
1516 : void rq_flush_dcache_pages(struct request *rq)
1517 : {
1518 : struct req_iterator iter;
1519 : struct bio_vec bvec;
1520 :
1521 : rq_for_each_segment(bvec, rq, iter)
1522 : flush_dcache_page(bvec.bv_page);
1523 : }
1524 : EXPORT_SYMBOL_GPL(rq_flush_dcache_pages);
1525 : #endif
1526 :
1527 : /**
1528 : * blk_lld_busy - Check if underlying low-level drivers of a device are busy
1529 : * @q : the queue of the device being checked
1530 : *
1531 : * Description:
1532 : * Check if underlying low-level drivers of a device are busy.
1533 : * If the drivers want to export their busy state, they must set own
1534 : * exporting function using blk_queue_lld_busy() first.
1535 : *
1536 : * Basically, this function is used only by request stacking drivers
1537 : * to stop dispatching requests to underlying devices when underlying
1538 : * devices are busy. This behavior helps more I/O merging on the queue
1539 : * of the request stacking driver and prevents I/O throughput regression
1540 : * on burst I/O load.
1541 : *
1542 : * Return:
1543 : * 0 - Not busy (The request stacking driver should dispatch request)
1544 : * 1 - Busy (The request stacking driver should stop dispatching request)
1545 : */
1546 0 : int blk_lld_busy(struct request_queue *q)
1547 : {
1548 0 : if (queue_is_mq(q) && q->mq_ops->busy)
1549 0 : return q->mq_ops->busy(q);
1550 :
1551 : return 0;
1552 : }
1553 : EXPORT_SYMBOL_GPL(blk_lld_busy);
1554 :
1555 : /**
1556 : * blk_rq_unprep_clone - Helper function to free all bios in a cloned request
1557 : * @rq: the clone request to be cleaned up
1558 : *
1559 : * Description:
1560 : * Free all bios in @rq for a cloned request.
1561 : */
1562 0 : void blk_rq_unprep_clone(struct request *rq)
1563 : {
1564 0 : struct bio *bio;
1565 :
1566 0 : while ((bio = rq->bio) != NULL) {
1567 0 : rq->bio = bio->bi_next;
1568 :
1569 0 : bio_put(bio);
1570 : }
1571 0 : }
1572 : EXPORT_SYMBOL_GPL(blk_rq_unprep_clone);
1573 :
1574 : /**
1575 : * blk_rq_prep_clone - Helper function to setup clone request
1576 : * @rq: the request to be setup
1577 : * @rq_src: original request to be cloned
1578 : * @bs: bio_set that bios for clone are allocated from
1579 : * @gfp_mask: memory allocation mask for bio
1580 : * @bio_ctr: setup function to be called for each clone bio.
1581 : * Returns %0 for success, non %0 for failure.
1582 : * @data: private data to be passed to @bio_ctr
1583 : *
1584 : * Description:
1585 : * Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq.
1586 : * Also, pages which the original bios are pointing to are not copied
1587 : * and the cloned bios just point same pages.
1588 : * So cloned bios must be completed before original bios, which means
1589 : * the caller must complete @rq before @rq_src.
1590 : */
1591 0 : int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
1592 : struct bio_set *bs, gfp_t gfp_mask,
1593 : int (*bio_ctr)(struct bio *, struct bio *, void *),
1594 : void *data)
1595 : {
1596 0 : struct bio *bio, *bio_src;
1597 :
1598 0 : if (!bs)
1599 0 : bs = &fs_bio_set;
1600 :
1601 0 : __rq_for_each_bio(bio_src, rq_src) {
1602 0 : bio = bio_clone_fast(bio_src, gfp_mask, bs);
1603 0 : if (!bio)
1604 0 : goto free_and_out;
1605 :
1606 0 : if (bio_ctr && bio_ctr(bio, bio_src, data))
1607 0 : goto free_and_out;
1608 :
1609 0 : if (rq->bio) {
1610 0 : rq->biotail->bi_next = bio;
1611 0 : rq->biotail = bio;
1612 : } else {
1613 0 : rq->bio = rq->biotail = bio;
1614 : }
1615 0 : bio = NULL;
1616 : }
1617 :
1618 : /* Copy attributes of the original request to the clone request. */
1619 0 : rq->__sector = blk_rq_pos(rq_src);
1620 0 : rq->__data_len = blk_rq_bytes(rq_src);
1621 0 : if (rq_src->rq_flags & RQF_SPECIAL_PAYLOAD) {
1622 0 : rq->rq_flags |= RQF_SPECIAL_PAYLOAD;
1623 0 : rq->special_vec = rq_src->special_vec;
1624 : }
1625 0 : rq->nr_phys_segments = rq_src->nr_phys_segments;
1626 0 : rq->ioprio = rq_src->ioprio;
1627 :
1628 0 : if (rq->bio && blk_crypto_rq_bio_prep(rq, rq->bio, gfp_mask) < 0)
1629 : goto free_and_out;
1630 :
1631 0 : return 0;
1632 :
1633 0 : free_and_out:
1634 0 : if (bio)
1635 0 : bio_put(bio);
1636 0 : blk_rq_unprep_clone(rq);
1637 :
1638 0 : return -ENOMEM;
1639 : }
1640 : EXPORT_SYMBOL_GPL(blk_rq_prep_clone);
1641 :
1642 8 : int kblockd_schedule_work(struct work_struct *work)
1643 : {
1644 8 : return queue_work(kblockd_workqueue, work);
1645 : }
1646 : EXPORT_SYMBOL(kblockd_schedule_work);
1647 :
1648 265 : int kblockd_mod_delayed_work_on(int cpu, struct delayed_work *dwork,
1649 : unsigned long delay)
1650 : {
1651 265 : return mod_delayed_work_on(cpu, kblockd_workqueue, dwork, delay);
1652 : }
1653 : EXPORT_SYMBOL(kblockd_mod_delayed_work_on);
1654 :
1655 : /**
1656 : * blk_start_plug - initialize blk_plug and track it inside the task_struct
1657 : * @plug: The &struct blk_plug that needs to be initialized
1658 : *
1659 : * Description:
1660 : * blk_start_plug() indicates to the block layer an intent by the caller
1661 : * to submit multiple I/O requests in a batch. The block layer may use
1662 : * this hint to defer submitting I/Os from the caller until blk_finish_plug()
1663 : * is called. However, the block layer may choose to submit requests
1664 : * before a call to blk_finish_plug() if the number of queued I/Os
1665 : * exceeds %BLK_MAX_REQUEST_COUNT, or if the size of the I/O is larger than
1666 : * %BLK_PLUG_FLUSH_SIZE. The queued I/Os may also be submitted early if
1667 : * the task schedules (see below).
1668 : *
1669 : * Tracking blk_plug inside the task_struct will help with auto-flushing the
1670 : * pending I/O should the task end up blocking between blk_start_plug() and
1671 : * blk_finish_plug(). This is important from a performance perspective, but
1672 : * also ensures that we don't deadlock. For instance, if the task is blocking
1673 : * for a memory allocation, memory reclaim could end up wanting to free a
1674 : * page belonging to that request that is currently residing in our private
1675 : * plug. By flushing the pending I/O when the process goes to sleep, we avoid
1676 : * this kind of deadlock.
1677 : */
1678 2114 : void blk_start_plug(struct blk_plug *plug)
1679 : {
1680 2114 : struct task_struct *tsk = current;
1681 :
1682 : /*
1683 : * If this is a nested plug, don't actually assign it.
1684 : */
1685 2114 : if (tsk->plug)
1686 : return;
1687 :
1688 2028 : INIT_LIST_HEAD(&plug->mq_list);
1689 2028 : INIT_LIST_HEAD(&plug->cb_list);
1690 2028 : plug->rq_count = 0;
1691 2028 : plug->multiple_queues = false;
1692 2028 : plug->nowait = false;
1693 :
1694 : /*
1695 : * Store ordering should not be needed here, since a potential
1696 : * preempt will imply a full memory barrier
1697 : */
1698 2028 : tsk->plug = plug;
1699 : }
1700 : EXPORT_SYMBOL(blk_start_plug);
1701 :
1702 2072 : static void flush_plug_callbacks(struct blk_plug *plug, bool from_schedule)
1703 : {
1704 2072 : LIST_HEAD(callbacks);
1705 :
1706 2072 : while (!list_empty(&plug->cb_list)) {
1707 0 : list_splice_init(&plug->cb_list, &callbacks);
1708 :
1709 0 : while (!list_empty(&callbacks)) {
1710 0 : struct blk_plug_cb *cb = list_first_entry(&callbacks,
1711 : struct blk_plug_cb,
1712 : list);
1713 0 : list_del(&cb->list);
1714 0 : cb->callback(cb, from_schedule);
1715 : }
1716 : }
1717 2072 : }
1718 :
1719 0 : struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug, void *data,
1720 : int size)
1721 : {
1722 0 : struct blk_plug *plug = current->plug;
1723 0 : struct blk_plug_cb *cb;
1724 :
1725 0 : if (!plug)
1726 : return NULL;
1727 :
1728 0 : list_for_each_entry(cb, &plug->cb_list, list)
1729 0 : if (cb->callback == unplug && cb->data == data)
1730 0 : return cb;
1731 :
1732 : /* Not currently on the callback list */
1733 0 : BUG_ON(size < sizeof(*cb));
1734 0 : cb = kzalloc(size, GFP_ATOMIC);
1735 0 : if (cb) {
1736 0 : cb->data = data;
1737 0 : cb->callback = unplug;
1738 0 : list_add(&cb->list, &plug->cb_list);
1739 : }
1740 : return cb;
1741 : }
1742 : EXPORT_SYMBOL(blk_check_plugged);
1743 :
1744 2072 : void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule)
1745 : {
1746 2072 : flush_plug_callbacks(plug, from_schedule);
1747 :
1748 2072 : if (!list_empty(&plug->mq_list))
1749 1880 : blk_mq_flush_plug_list(plug, from_schedule);
1750 2072 : }
1751 :
1752 : /**
1753 : * blk_finish_plug - mark the end of a batch of submitted I/O
1754 : * @plug: The &struct blk_plug passed to blk_start_plug()
1755 : *
1756 : * Description:
1757 : * Indicate that a batch of I/O submissions is complete. This function
1758 : * must be paired with an initial call to blk_start_plug(). The intent
1759 : * is to allow the block layer to optimize I/O submission. See the
1760 : * documentation for blk_start_plug() for more information.
1761 : */
1762 2114 : void blk_finish_plug(struct blk_plug *plug)
1763 : {
1764 2114 : if (plug != current->plug)
1765 : return;
1766 2028 : blk_flush_plug_list(plug, false);
1767 :
1768 2028 : current->plug = NULL;
1769 : }
1770 : EXPORT_SYMBOL(blk_finish_plug);
1771 :
1772 0 : void blk_io_schedule(void)
1773 : {
1774 : /* Prevent hang_check timer from firing at us during very long I/O */
1775 0 : unsigned long timeout = sysctl_hung_task_timeout_secs * HZ / 2;
1776 :
1777 0 : if (timeout)
1778 : io_schedule_timeout(timeout);
1779 : else
1780 0 : io_schedule();
1781 0 : }
1782 : EXPORT_SYMBOL_GPL(blk_io_schedule);
1783 :
1784 1 : int __init blk_dev_init(void)
1785 : {
1786 1 : BUILD_BUG_ON(REQ_OP_LAST >= (1 << REQ_OP_BITS));
1787 1 : BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 *
1788 : sizeof_field(struct request, cmd_flags));
1789 1 : BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 *
1790 : sizeof_field(struct bio, bi_opf));
1791 :
1792 : /* used for unplugging and affects IO latency/throughput - HIGHPRI */
1793 1 : kblockd_workqueue = alloc_workqueue("kblockd",
1794 : WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
1795 1 : if (!kblockd_workqueue)
1796 0 : panic("Failed to create kblockd\n");
1797 :
1798 1 : blk_requestq_cachep = kmem_cache_create("request_queue",
1799 : sizeof(struct request_queue), 0, SLAB_PANIC, NULL);
1800 :
1801 1 : blk_debugfs_root = debugfs_create_dir("block", NULL);
1802 :
1803 1 : return 0;
1804 : }
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