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1 | /* | |
2 | * Copyright (C) 1991, 1992 Linus Torvalds | |
3 | * Copyright (C) 1994, Karl Keyte: Added support for disk statistics | |
4 | * Elevator latency, (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE | |
5 | * Queue request tables / lock, selectable elevator, Jens Axboe <axboe@suse.de> | |
6 | * kernel-doc documentation started by NeilBrown <neilb@cse.unsw.edu.au> | |
7 | * - July2000 | |
8 | * bio rewrite, highmem i/o, etc, Jens Axboe <axboe@suse.de> - may 2001 | |
9 | */ | |
10 | ||
11 | /* | |
12 | * This handles all read/write requests to block devices | |
13 | */ | |
14 | #include <linux/kernel.h> | |
15 | #include <linux/module.h> | |
16 | #include <linux/backing-dev.h> | |
17 | #include <linux/bio.h> | |
18 | #include <linux/blkdev.h> | |
19 | #include <linux/blk-mq.h> | |
20 | #include <linux/highmem.h> | |
21 | #include <linux/mm.h> | |
22 | #include <linux/kernel_stat.h> | |
23 | #include <linux/string.h> | |
24 | #include <linux/init.h> | |
25 | #include <linux/completion.h> | |
26 | #include <linux/slab.h> | |
27 | #include <linux/swap.h> | |
28 | #include <linux/writeback.h> | |
29 | #include <linux/task_io_accounting_ops.h> | |
30 | #include <linux/fault-inject.h> | |
31 | #include <linux/list_sort.h> | |
32 | #include <linux/delay.h> | |
33 | #include <linux/ratelimit.h> | |
34 | #include <linux/pm_runtime.h> | |
35 | #include <linux/blk-cgroup.h> | |
36 | ||
37 | #define CREATE_TRACE_POINTS | |
38 | #include <trace/events/block.h> | |
39 | ||
40 | #include "blk.h" | |
41 | #include "blk-mq.h" | |
42 | ||
43 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap); | |
44 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap); | |
45 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete); | |
46 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_split); | |
47 | EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug); | |
48 | ||
49 | DEFINE_IDA(blk_queue_ida); | |
50 | ||
51 | /* | |
52 | * For the allocated request tables | |
53 | */ | |
54 | struct kmem_cache *request_cachep = NULL; | |
55 | ||
56 | /* | |
57 | * For queue allocation | |
58 | */ | |
59 | struct kmem_cache *blk_requestq_cachep; | |
60 | ||
61 | /* | |
62 | * Controlling structure to kblockd | |
63 | */ | |
64 | static struct workqueue_struct *kblockd_workqueue; | |
65 | ||
66 | static void blk_clear_congested(struct request_list *rl, int sync) | |
67 | { | |
68 | #ifdef CONFIG_CGROUP_WRITEBACK | |
69 | clear_wb_congested(rl->blkg->wb_congested, sync); | |
70 | #else | |
71 | /* | |
72 | * If !CGROUP_WRITEBACK, all blkg's map to bdi->wb and we shouldn't | |
73 | * flip its congestion state for events on other blkcgs. | |
74 | */ | |
75 | if (rl == &rl->q->root_rl) | |
76 | clear_wb_congested(rl->q->backing_dev_info.wb.congested, sync); | |
77 | #endif | |
78 | } | |
79 | ||
80 | static void blk_set_congested(struct request_list *rl, int sync) | |
81 | { | |
82 | #ifdef CONFIG_CGROUP_WRITEBACK | |
83 | set_wb_congested(rl->blkg->wb_congested, sync); | |
84 | #else | |
85 | /* see blk_clear_congested() */ | |
86 | if (rl == &rl->q->root_rl) | |
87 | set_wb_congested(rl->q->backing_dev_info.wb.congested, sync); | |
88 | #endif | |
89 | } | |
90 | ||
91 | void blk_queue_congestion_threshold(struct request_queue *q) | |
92 | { | |
93 | int nr; | |
94 | ||
95 | nr = q->nr_requests - (q->nr_requests / 8) + 1; | |
96 | if (nr > q->nr_requests) | |
97 | nr = q->nr_requests; | |
98 | q->nr_congestion_on = nr; | |
99 | ||
100 | nr = q->nr_requests - (q->nr_requests / 8) - (q->nr_requests / 16) - 1; | |
101 | if (nr < 1) | |
102 | nr = 1; | |
103 | q->nr_congestion_off = nr; | |
104 | } | |
105 | ||
106 | /** | |
107 | * blk_get_backing_dev_info - get the address of a queue's backing_dev_info | |
108 | * @bdev: device | |
109 | * | |
110 | * Locates the passed device's request queue and returns the address of its | |
111 | * backing_dev_info. This function can only be called if @bdev is opened | |
112 | * and the return value is never NULL. | |
113 | */ | |
114 | struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev) | |
115 | { | |
116 | struct request_queue *q = bdev_get_queue(bdev); | |
117 | ||
118 | return &q->backing_dev_info; | |
119 | } | |
120 | EXPORT_SYMBOL(blk_get_backing_dev_info); | |
121 | ||
122 | void blk_rq_init(struct request_queue *q, struct request *rq) | |
123 | { | |
124 | memset(rq, 0, sizeof(*rq)); | |
125 | ||
126 | INIT_LIST_HEAD(&rq->queuelist); | |
127 | INIT_LIST_HEAD(&rq->timeout_list); | |
128 | rq->cpu = -1; | |
129 | rq->q = q; | |
130 | rq->__sector = (sector_t) -1; | |
131 | INIT_HLIST_NODE(&rq->hash); | |
132 | RB_CLEAR_NODE(&rq->rb_node); | |
133 | rq->cmd = rq->__cmd; | |
134 | rq->cmd_len = BLK_MAX_CDB; | |
135 | rq->tag = -1; | |
136 | rq->start_time = jiffies; | |
137 | set_start_time_ns(rq); | |
138 | rq->part = NULL; | |
139 | } | |
140 | EXPORT_SYMBOL(blk_rq_init); | |
141 | ||
142 | static void req_bio_endio(struct request *rq, struct bio *bio, | |
143 | unsigned int nbytes, int error) | |
144 | { | |
145 | if (error) | |
146 | bio->bi_error = error; | |
147 | ||
148 | if (unlikely(rq->cmd_flags & REQ_QUIET)) | |
149 | bio_set_flag(bio, BIO_QUIET); | |
150 | ||
151 | bio_advance(bio, nbytes); | |
152 | ||
153 | /* don't actually finish bio if it's part of flush sequence */ | |
154 | if (bio->bi_iter.bi_size == 0 && !(rq->cmd_flags & REQ_FLUSH_SEQ)) | |
155 | bio_endio(bio); | |
156 | } | |
157 | ||
158 | void blk_dump_rq_flags(struct request *rq, char *msg) | |
159 | { | |
160 | int bit; | |
161 | ||
162 | printk(KERN_INFO "%s: dev %s: type=%x, flags=%llx\n", msg, | |
163 | rq->rq_disk ? rq->rq_disk->disk_name : "?", rq->cmd_type, | |
164 | (unsigned long long) rq->cmd_flags); | |
165 | ||
166 | printk(KERN_INFO " sector %llu, nr/cnr %u/%u\n", | |
167 | (unsigned long long)blk_rq_pos(rq), | |
168 | blk_rq_sectors(rq), blk_rq_cur_sectors(rq)); | |
169 | printk(KERN_INFO " bio %p, biotail %p, len %u\n", | |
170 | rq->bio, rq->biotail, blk_rq_bytes(rq)); | |
171 | ||
172 | if (rq->cmd_type == REQ_TYPE_BLOCK_PC) { | |
173 | printk(KERN_INFO " cdb: "); | |
174 | for (bit = 0; bit < BLK_MAX_CDB; bit++) | |
175 | printk("%02x ", rq->cmd[bit]); | |
176 | printk("\n"); | |
177 | } | |
178 | } | |
179 | EXPORT_SYMBOL(blk_dump_rq_flags); | |
180 | ||
181 | static void blk_delay_work(struct work_struct *work) | |
182 | { | |
183 | struct request_queue *q; | |
184 | ||
185 | q = container_of(work, struct request_queue, delay_work.work); | |
186 | spin_lock_irq(q->queue_lock); | |
187 | __blk_run_queue(q); | |
188 | spin_unlock_irq(q->queue_lock); | |
189 | } | |
190 | ||
191 | /** | |
192 | * blk_delay_queue - restart queueing after defined interval | |
193 | * @q: The &struct request_queue in question | |
194 | * @msecs: Delay in msecs | |
195 | * | |
196 | * Description: | |
197 | * Sometimes queueing needs to be postponed for a little while, to allow | |
198 | * resources to come back. This function will make sure that queueing is | |
199 | * restarted around the specified time. Queue lock must be held. | |
200 | */ | |
201 | void blk_delay_queue(struct request_queue *q, unsigned long msecs) | |
202 | { | |
203 | if (likely(!blk_queue_dead(q))) | |
204 | queue_delayed_work(kblockd_workqueue, &q->delay_work, | |
205 | msecs_to_jiffies(msecs)); | |
206 | } | |
207 | EXPORT_SYMBOL(blk_delay_queue); | |
208 | ||
209 | /** | |
210 | * blk_start_queue - restart a previously stopped queue | |
211 | * @q: The &struct request_queue in question | |
212 | * | |
213 | * Description: | |
214 | * blk_start_queue() will clear the stop flag on the queue, and call | |
215 | * the request_fn for the queue if it was in a stopped state when | |
216 | * entered. Also see blk_stop_queue(). Queue lock must be held. | |
217 | **/ | |
218 | void blk_start_queue(struct request_queue *q) | |
219 | { | |
220 | WARN_ON(!irqs_disabled()); | |
221 | ||
222 | queue_flag_clear(QUEUE_FLAG_STOPPED, q); | |
223 | __blk_run_queue(q); | |
224 | } | |
225 | EXPORT_SYMBOL(blk_start_queue); | |
226 | ||
227 | /** | |
228 | * blk_stop_queue - stop a queue | |
229 | * @q: The &struct request_queue in question | |
230 | * | |
231 | * Description: | |
232 | * The Linux block layer assumes that a block driver will consume all | |
233 | * entries on the request queue when the request_fn strategy is called. | |
234 | * Often this will not happen, because of hardware limitations (queue | |
235 | * depth settings). If a device driver gets a 'queue full' response, | |
236 | * or if it simply chooses not to queue more I/O at one point, it can | |
237 | * call this function to prevent the request_fn from being called until | |
238 | * the driver has signalled it's ready to go again. This happens by calling | |
239 | * blk_start_queue() to restart queue operations. Queue lock must be held. | |
240 | **/ | |
241 | void blk_stop_queue(struct request_queue *q) | |
242 | { | |
243 | cancel_delayed_work(&q->delay_work); | |
244 | queue_flag_set(QUEUE_FLAG_STOPPED, q); | |
245 | } | |
246 | EXPORT_SYMBOL(blk_stop_queue); | |
247 | ||
248 | /** | |
249 | * blk_sync_queue - cancel any pending callbacks on a queue | |
250 | * @q: the queue | |
251 | * | |
252 | * Description: | |
253 | * The block layer may perform asynchronous callback activity | |
254 | * on a queue, such as calling the unplug function after a timeout. | |
255 | * A block device may call blk_sync_queue to ensure that any | |
256 | * such activity is cancelled, thus allowing it to release resources | |
257 | * that the callbacks might use. The caller must already have made sure | |
258 | * that its ->make_request_fn will not re-add plugging prior to calling | |
259 | * this function. | |
260 | * | |
261 | * This function does not cancel any asynchronous activity arising | |
262 | * out of elevator or throttling code. That would require elevator_exit() | |
263 | * and blkcg_exit_queue() to be called with queue lock initialized. | |
264 | * | |
265 | */ | |
266 | void blk_sync_queue(struct request_queue *q) | |
267 | { | |
268 | del_timer_sync(&q->timeout); | |
269 | ||
270 | if (q->mq_ops) { | |
271 | struct blk_mq_hw_ctx *hctx; | |
272 | int i; | |
273 | ||
274 | queue_for_each_hw_ctx(q, hctx, i) { | |
275 | cancel_delayed_work_sync(&hctx->run_work); | |
276 | cancel_delayed_work_sync(&hctx->delay_work); | |
277 | } | |
278 | } else { | |
279 | cancel_delayed_work_sync(&q->delay_work); | |
280 | } | |
281 | } | |
282 | EXPORT_SYMBOL(blk_sync_queue); | |
283 | ||
284 | /** | |
285 | * __blk_run_queue_uncond - run a queue whether or not it has been stopped | |
286 | * @q: The queue to run | |
287 | * | |
288 | * Description: | |
289 | * Invoke request handling on a queue if there are any pending requests. | |
290 | * May be used to restart request handling after a request has completed. | |
291 | * This variant runs the queue whether or not the queue has been | |
292 | * stopped. Must be called with the queue lock held and interrupts | |
293 | * disabled. See also @blk_run_queue. | |
294 | */ | |
295 | inline void __blk_run_queue_uncond(struct request_queue *q) | |
296 | { | |
297 | if (unlikely(blk_queue_dead(q))) | |
298 | return; | |
299 | ||
300 | /* | |
301 | * Some request_fn implementations, e.g. scsi_request_fn(), unlock | |
302 | * the queue lock internally. As a result multiple threads may be | |
303 | * running such a request function concurrently. Keep track of the | |
304 | * number of active request_fn invocations such that blk_drain_queue() | |
305 | * can wait until all these request_fn calls have finished. | |
306 | */ | |
307 | q->request_fn_active++; | |
308 | q->request_fn(q); | |
309 | q->request_fn_active--; | |
310 | } | |
311 | EXPORT_SYMBOL_GPL(__blk_run_queue_uncond); | |
312 | ||
313 | /** | |
314 | * __blk_run_queue - run a single device queue | |
315 | * @q: The queue to run | |
316 | * | |
317 | * Description: | |
318 | * See @blk_run_queue. This variant must be called with the queue lock | |
319 | * held and interrupts disabled. | |
320 | */ | |
321 | void __blk_run_queue(struct request_queue *q) | |
322 | { | |
323 | if (unlikely(blk_queue_stopped(q))) | |
324 | return; | |
325 | ||
326 | __blk_run_queue_uncond(q); | |
327 | } | |
328 | EXPORT_SYMBOL(__blk_run_queue); | |
329 | ||
330 | /** | |
331 | * blk_run_queue_async - run a single device queue in workqueue context | |
332 | * @q: The queue to run | |
333 | * | |
334 | * Description: | |
335 | * Tells kblockd to perform the equivalent of @blk_run_queue on behalf | |
336 | * of us. The caller must hold the queue lock. | |
337 | */ | |
338 | void blk_run_queue_async(struct request_queue *q) | |
339 | { | |
340 | if (likely(!blk_queue_stopped(q) && !blk_queue_dead(q))) | |
341 | mod_delayed_work(kblockd_workqueue, &q->delay_work, 0); | |
342 | } | |
343 | EXPORT_SYMBOL(blk_run_queue_async); | |
344 | ||
345 | /** | |
346 | * blk_run_queue - run a single device queue | |
347 | * @q: The queue to run | |
348 | * | |
349 | * Description: | |
350 | * Invoke request handling on this queue, if it has pending work to do. | |
351 | * May be used to restart queueing when a request has completed. | |
352 | */ | |
353 | void blk_run_queue(struct request_queue *q) | |
354 | { | |
355 | unsigned long flags; | |
356 | ||
357 | spin_lock_irqsave(q->queue_lock, flags); | |
358 | __blk_run_queue(q); | |
359 | spin_unlock_irqrestore(q->queue_lock, flags); | |
360 | } | |
361 | EXPORT_SYMBOL(blk_run_queue); | |
362 | ||
363 | void blk_put_queue(struct request_queue *q) | |
364 | { | |
365 | kobject_put(&q->kobj); | |
366 | } | |
367 | EXPORT_SYMBOL(blk_put_queue); | |
368 | ||
369 | /** | |
370 | * __blk_drain_queue - drain requests from request_queue | |
371 | * @q: queue to drain | |
372 | * @drain_all: whether to drain all requests or only the ones w/ ELVPRIV | |
373 | * | |
374 | * Drain requests from @q. If @drain_all is set, all requests are drained. | |
375 | * If not, only ELVPRIV requests are drained. The caller is responsible | |
376 | * for ensuring that no new requests which need to be drained are queued. | |
377 | */ | |
378 | static void __blk_drain_queue(struct request_queue *q, bool drain_all) | |
379 | __releases(q->queue_lock) | |
380 | __acquires(q->queue_lock) | |
381 | { | |
382 | int i; | |
383 | ||
384 | lockdep_assert_held(q->queue_lock); | |
385 | ||
386 | while (true) { | |
387 | bool drain = false; | |
388 | ||
389 | /* | |
390 | * The caller might be trying to drain @q before its | |
391 | * elevator is initialized. | |
392 | */ | |
393 | if (q->elevator) | |
394 | elv_drain_elevator(q); | |
395 | ||
396 | blkcg_drain_queue(q); | |
397 | ||
398 | /* | |
399 | * This function might be called on a queue which failed | |
400 | * driver init after queue creation or is not yet fully | |
401 | * active yet. Some drivers (e.g. fd and loop) get unhappy | |
402 | * in such cases. Kick queue iff dispatch queue has | |
403 | * something on it and @q has request_fn set. | |
404 | */ | |
405 | if (!list_empty(&q->queue_head) && q->request_fn) | |
406 | __blk_run_queue(q); | |
407 | ||
408 | drain |= q->nr_rqs_elvpriv; | |
409 | drain |= q->request_fn_active; | |
410 | ||
411 | /* | |
412 | * Unfortunately, requests are queued at and tracked from | |
413 | * multiple places and there's no single counter which can | |
414 | * be drained. Check all the queues and counters. | |
415 | */ | |
416 | if (drain_all) { | |
417 | struct blk_flush_queue *fq = blk_get_flush_queue(q, NULL); | |
418 | drain |= !list_empty(&q->queue_head); | |
419 | for (i = 0; i < 2; i++) { | |
420 | drain |= q->nr_rqs[i]; | |
421 | drain |= q->in_flight[i]; | |
422 | if (fq) | |
423 | drain |= !list_empty(&fq->flush_queue[i]); | |
424 | } | |
425 | } | |
426 | ||
427 | if (!drain) | |
428 | break; | |
429 | ||
430 | spin_unlock_irq(q->queue_lock); | |
431 | ||
432 | msleep(10); | |
433 | ||
434 | spin_lock_irq(q->queue_lock); | |
435 | } | |
436 | ||
437 | /* | |
438 | * With queue marked dead, any woken up waiter will fail the | |
439 | * allocation path, so the wakeup chaining is lost and we're | |
440 | * left with hung waiters. We need to wake up those waiters. | |
441 | */ | |
442 | if (q->request_fn) { | |
443 | struct request_list *rl; | |
444 | ||
445 | blk_queue_for_each_rl(rl, q) | |
446 | for (i = 0; i < ARRAY_SIZE(rl->wait); i++) | |
447 | wake_up_all(&rl->wait[i]); | |
448 | } | |
449 | } | |
450 | ||
451 | /** | |
452 | * blk_queue_bypass_start - enter queue bypass mode | |
453 | * @q: queue of interest | |
454 | * | |
455 | * In bypass mode, only the dispatch FIFO queue of @q is used. This | |
456 | * function makes @q enter bypass mode and drains all requests which were | |
457 | * throttled or issued before. On return, it's guaranteed that no request | |
458 | * is being throttled or has ELVPRIV set and blk_queue_bypass() %true | |
459 | * inside queue or RCU read lock. | |
460 | */ | |
461 | void blk_queue_bypass_start(struct request_queue *q) | |
462 | { | |
463 | spin_lock_irq(q->queue_lock); | |
464 | q->bypass_depth++; | |
465 | queue_flag_set(QUEUE_FLAG_BYPASS, q); | |
466 | spin_unlock_irq(q->queue_lock); | |
467 | ||
468 | /* | |
469 | * Queues start drained. Skip actual draining till init is | |
470 | * complete. This avoids lenghty delays during queue init which | |
471 | * can happen many times during boot. | |
472 | */ | |
473 | if (blk_queue_init_done(q)) { | |
474 | spin_lock_irq(q->queue_lock); | |
475 | __blk_drain_queue(q, false); | |
476 | spin_unlock_irq(q->queue_lock); | |
477 | ||
478 | /* ensure blk_queue_bypass() is %true inside RCU read lock */ | |
479 | synchronize_rcu(); | |
480 | } | |
481 | } | |
482 | EXPORT_SYMBOL_GPL(blk_queue_bypass_start); | |
483 | ||
484 | /** | |
485 | * blk_queue_bypass_end - leave queue bypass mode | |
486 | * @q: queue of interest | |
487 | * | |
488 | * Leave bypass mode and restore the normal queueing behavior. | |
489 | */ | |
490 | void blk_queue_bypass_end(struct request_queue *q) | |
491 | { | |
492 | spin_lock_irq(q->queue_lock); | |
493 | if (!--q->bypass_depth) | |
494 | queue_flag_clear(QUEUE_FLAG_BYPASS, q); | |
495 | WARN_ON_ONCE(q->bypass_depth < 0); | |
496 | spin_unlock_irq(q->queue_lock); | |
497 | } | |
498 | EXPORT_SYMBOL_GPL(blk_queue_bypass_end); | |
499 | ||
500 | void blk_set_queue_dying(struct request_queue *q) | |
501 | { | |
502 | queue_flag_set_unlocked(QUEUE_FLAG_DYING, q); | |
503 | ||
504 | if (q->mq_ops) | |
505 | blk_mq_wake_waiters(q); | |
506 | else { | |
507 | struct request_list *rl; | |
508 | ||
509 | blk_queue_for_each_rl(rl, q) { | |
510 | if (rl->rq_pool) { | |
511 | wake_up(&rl->wait[BLK_RW_SYNC]); | |
512 | wake_up(&rl->wait[BLK_RW_ASYNC]); | |
513 | } | |
514 | } | |
515 | } | |
516 | } | |
517 | EXPORT_SYMBOL_GPL(blk_set_queue_dying); | |
518 | ||
519 | /** | |
520 | * blk_cleanup_queue - shutdown a request queue | |
521 | * @q: request queue to shutdown | |
522 | * | |
523 | * Mark @q DYING, drain all pending requests, mark @q DEAD, destroy and | |
524 | * put it. All future requests will be failed immediately with -ENODEV. | |
525 | */ | |
526 | void blk_cleanup_queue(struct request_queue *q) | |
527 | { | |
528 | spinlock_t *lock = q->queue_lock; | |
529 | ||
530 | /* mark @q DYING, no new request or merges will be allowed afterwards */ | |
531 | mutex_lock(&q->sysfs_lock); | |
532 | blk_set_queue_dying(q); | |
533 | spin_lock_irq(lock); | |
534 | ||
535 | /* | |
536 | * A dying queue is permanently in bypass mode till released. Note | |
537 | * that, unlike blk_queue_bypass_start(), we aren't performing | |
538 | * synchronize_rcu() after entering bypass mode to avoid the delay | |
539 | * as some drivers create and destroy a lot of queues while | |
540 | * probing. This is still safe because blk_release_queue() will be | |
541 | * called only after the queue refcnt drops to zero and nothing, | |
542 | * RCU or not, would be traversing the queue by then. | |
543 | */ | |
544 | q->bypass_depth++; | |
545 | queue_flag_set(QUEUE_FLAG_BYPASS, q); | |
546 | ||
547 | queue_flag_set(QUEUE_FLAG_NOMERGES, q); | |
548 | queue_flag_set(QUEUE_FLAG_NOXMERGES, q); | |
549 | queue_flag_set(QUEUE_FLAG_DYING, q); | |
550 | spin_unlock_irq(lock); | |
551 | mutex_unlock(&q->sysfs_lock); | |
552 | ||
553 | /* | |
554 | * Drain all requests queued before DYING marking. Set DEAD flag to | |
555 | * prevent that q->request_fn() gets invoked after draining finished. | |
556 | */ | |
557 | if (q->mq_ops) { | |
558 | blk_mq_freeze_queue(q); | |
559 | spin_lock_irq(lock); | |
560 | } else { | |
561 | spin_lock_irq(lock); | |
562 | __blk_drain_queue(q, true); | |
563 | } | |
564 | queue_flag_set(QUEUE_FLAG_DEAD, q); | |
565 | spin_unlock_irq(lock); | |
566 | ||
567 | /* @q won't process any more request, flush async actions */ | |
568 | del_timer_sync(&q->backing_dev_info.laptop_mode_wb_timer); | |
569 | blk_sync_queue(q); | |
570 | ||
571 | if (q->mq_ops) | |
572 | blk_mq_free_queue(q); | |
573 | ||
574 | spin_lock_irq(lock); | |
575 | if (q->queue_lock != &q->__queue_lock) | |
576 | q->queue_lock = &q->__queue_lock; | |
577 | spin_unlock_irq(lock); | |
578 | ||
579 | bdi_destroy(&q->backing_dev_info); | |
580 | ||
581 | /* @q is and will stay empty, shutdown and put */ | |
582 | blk_put_queue(q); | |
583 | } | |
584 | EXPORT_SYMBOL(blk_cleanup_queue); | |
585 | ||
586 | /* Allocate memory local to the request queue */ | |
587 | static void *alloc_request_struct(gfp_t gfp_mask, void *data) | |
588 | { | |
589 | int nid = (int)(long)data; | |
590 | return kmem_cache_alloc_node(request_cachep, gfp_mask, nid); | |
591 | } | |
592 | ||
593 | static void free_request_struct(void *element, void *unused) | |
594 | { | |
595 | kmem_cache_free(request_cachep, element); | |
596 | } | |
597 | ||
598 | int blk_init_rl(struct request_list *rl, struct request_queue *q, | |
599 | gfp_t gfp_mask) | |
600 | { | |
601 | if (unlikely(rl->rq_pool)) | |
602 | return 0; | |
603 | ||
604 | rl->q = q; | |
605 | rl->count[BLK_RW_SYNC] = rl->count[BLK_RW_ASYNC] = 0; | |
606 | rl->starved[BLK_RW_SYNC] = rl->starved[BLK_RW_ASYNC] = 0; | |
607 | init_waitqueue_head(&rl->wait[BLK_RW_SYNC]); | |
608 | init_waitqueue_head(&rl->wait[BLK_RW_ASYNC]); | |
609 | ||
610 | rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ, alloc_request_struct, | |
611 | free_request_struct, | |
612 | (void *)(long)q->node, gfp_mask, | |
613 | q->node); | |
614 | if (!rl->rq_pool) | |
615 | return -ENOMEM; | |
616 | ||
617 | return 0; | |
618 | } | |
619 | ||
620 | void blk_exit_rl(struct request_list *rl) | |
621 | { | |
622 | if (rl->rq_pool) | |
623 | mempool_destroy(rl->rq_pool); | |
624 | } | |
625 | ||
626 | struct request_queue *blk_alloc_queue(gfp_t gfp_mask) | |
627 | { | |
628 | return blk_alloc_queue_node(gfp_mask, NUMA_NO_NODE); | |
629 | } | |
630 | EXPORT_SYMBOL(blk_alloc_queue); | |
631 | ||
632 | struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id) | |
633 | { | |
634 | struct request_queue *q; | |
635 | int err; | |
636 | ||
637 | q = kmem_cache_alloc_node(blk_requestq_cachep, | |
638 | gfp_mask | __GFP_ZERO, node_id); | |
639 | if (!q) | |
640 | return NULL; | |
641 | ||
642 | q->id = ida_simple_get(&blk_queue_ida, 0, 0, gfp_mask); | |
643 | if (q->id < 0) | |
644 | goto fail_q; | |
645 | ||
646 | q->bio_split = bioset_create(BIO_POOL_SIZE, 0); | |
647 | if (!q->bio_split) | |
648 | goto fail_id; | |
649 | ||
650 | q->backing_dev_info.ra_pages = | |
651 | (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; | |
652 | q->backing_dev_info.capabilities = BDI_CAP_CGROUP_WRITEBACK; | |
653 | q->backing_dev_info.name = "block"; | |
654 | q->node = node_id; | |
655 | ||
656 | err = bdi_init(&q->backing_dev_info); | |
657 | if (err) | |
658 | goto fail_split; | |
659 | ||
660 | setup_timer(&q->backing_dev_info.laptop_mode_wb_timer, | |
661 | laptop_mode_timer_fn, (unsigned long) q); | |
662 | setup_timer(&q->timeout, blk_rq_timed_out_timer, (unsigned long) q); | |
663 | INIT_LIST_HEAD(&q->queue_head); | |
664 | INIT_LIST_HEAD(&q->timeout_list); | |
665 | INIT_LIST_HEAD(&q->icq_list); | |
666 | #ifdef CONFIG_BLK_CGROUP | |
667 | INIT_LIST_HEAD(&q->blkg_list); | |
668 | #endif | |
669 | INIT_DELAYED_WORK(&q->delay_work, blk_delay_work); | |
670 | ||
671 | kobject_init(&q->kobj, &blk_queue_ktype); | |
672 | ||
673 | mutex_init(&q->sysfs_lock); | |
674 | spin_lock_init(&q->__queue_lock); | |
675 | ||
676 | /* | |
677 | * By default initialize queue_lock to internal lock and driver can | |
678 | * override it later if need be. | |
679 | */ | |
680 | q->queue_lock = &q->__queue_lock; | |
681 | ||
682 | /* | |
683 | * A queue starts its life with bypass turned on to avoid | |
684 | * unnecessary bypass on/off overhead and nasty surprises during | |
685 | * init. The initial bypass will be finished when the queue is | |
686 | * registered by blk_register_queue(). | |
687 | */ | |
688 | q->bypass_depth = 1; | |
689 | __set_bit(QUEUE_FLAG_BYPASS, &q->queue_flags); | |
690 | ||
691 | init_waitqueue_head(&q->mq_freeze_wq); | |
692 | ||
693 | if (blkcg_init_queue(q)) | |
694 | goto fail_bdi; | |
695 | ||
696 | return q; | |
697 | ||
698 | fail_bdi: | |
699 | bdi_destroy(&q->backing_dev_info); | |
700 | fail_split: | |
701 | bioset_free(q->bio_split); | |
702 | fail_id: | |
703 | ida_simple_remove(&blk_queue_ida, q->id); | |
704 | fail_q: | |
705 | kmem_cache_free(blk_requestq_cachep, q); | |
706 | return NULL; | |
707 | } | |
708 | EXPORT_SYMBOL(blk_alloc_queue_node); | |
709 | ||
710 | /** | |
711 | * blk_init_queue - prepare a request queue for use with a block device | |
712 | * @rfn: The function to be called to process requests that have been | |
713 | * placed on the queue. | |
714 | * @lock: Request queue spin lock | |
715 | * | |
716 | * Description: | |
717 | * If a block device wishes to use the standard request handling procedures, | |
718 | * which sorts requests and coalesces adjacent requests, then it must | |
719 | * call blk_init_queue(). The function @rfn will be called when there | |
720 | * are requests on the queue that need to be processed. If the device | |
721 | * supports plugging, then @rfn may not be called immediately when requests | |
722 | * are available on the queue, but may be called at some time later instead. | |
723 | * Plugged queues are generally unplugged when a buffer belonging to one | |
724 | * of the requests on the queue is needed, or due to memory pressure. | |
725 | * | |
726 | * @rfn is not required, or even expected, to remove all requests off the | |
727 | * queue, but only as many as it can handle at a time. If it does leave | |
728 | * requests on the queue, it is responsible for arranging that the requests | |
729 | * get dealt with eventually. | |
730 | * | |
731 | * The queue spin lock must be held while manipulating the requests on the | |
732 | * request queue; this lock will be taken also from interrupt context, so irq | |
733 | * disabling is needed for it. | |
734 | * | |
735 | * Function returns a pointer to the initialized request queue, or %NULL if | |
736 | * it didn't succeed. | |
737 | * | |
738 | * Note: | |
739 | * blk_init_queue() must be paired with a blk_cleanup_queue() call | |
740 | * when the block device is deactivated (such as at module unload). | |
741 | **/ | |
742 | ||
743 | struct request_queue *blk_init_queue(request_fn_proc *rfn, spinlock_t *lock) | |
744 | { | |
745 | return blk_init_queue_node(rfn, lock, NUMA_NO_NODE); | |
746 | } | |
747 | EXPORT_SYMBOL(blk_init_queue); | |
748 | ||
749 | struct request_queue * | |
750 | blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id) | |
751 | { | |
752 | struct request_queue *uninit_q, *q; | |
753 | ||
754 | uninit_q = blk_alloc_queue_node(GFP_KERNEL, node_id); | |
755 | if (!uninit_q) | |
756 | return NULL; | |
757 | ||
758 | q = blk_init_allocated_queue(uninit_q, rfn, lock); | |
759 | if (!q) | |
760 | blk_cleanup_queue(uninit_q); | |
761 | ||
762 | return q; | |
763 | } | |
764 | EXPORT_SYMBOL(blk_init_queue_node); | |
765 | ||
766 | static void blk_queue_bio(struct request_queue *q, struct bio *bio); | |
767 | ||
768 | struct request_queue * | |
769 | blk_init_allocated_queue(struct request_queue *q, request_fn_proc *rfn, | |
770 | spinlock_t *lock) | |
771 | { | |
772 | if (!q) | |
773 | return NULL; | |
774 | ||
775 | q->fq = blk_alloc_flush_queue(q, NUMA_NO_NODE, 0); | |
776 | if (!q->fq) | |
777 | return NULL; | |
778 | ||
779 | if (blk_init_rl(&q->root_rl, q, GFP_KERNEL)) | |
780 | goto fail; | |
781 | ||
782 | q->request_fn = rfn; | |
783 | q->prep_rq_fn = NULL; | |
784 | q->unprep_rq_fn = NULL; | |
785 | q->queue_flags |= QUEUE_FLAG_DEFAULT; | |
786 | ||
787 | /* Override internal queue lock with supplied lock pointer */ | |
788 | if (lock) | |
789 | q->queue_lock = lock; | |
790 | ||
791 | /* | |
792 | * This also sets hw/phys segments, boundary and size | |
793 | */ | |
794 | blk_queue_make_request(q, blk_queue_bio); | |
795 | ||
796 | q->sg_reserved_size = INT_MAX; | |
797 | ||
798 | /* Protect q->elevator from elevator_change */ | |
799 | mutex_lock(&q->sysfs_lock); | |
800 | ||
801 | /* init elevator */ | |
802 | if (elevator_init(q, NULL)) { | |
803 | mutex_unlock(&q->sysfs_lock); | |
804 | goto fail; | |
805 | } | |
806 | ||
807 | mutex_unlock(&q->sysfs_lock); | |
808 | ||
809 | return q; | |
810 | ||
811 | fail: | |
812 | blk_free_flush_queue(q->fq); | |
813 | return NULL; | |
814 | } | |
815 | EXPORT_SYMBOL(blk_init_allocated_queue); | |
816 | ||
817 | bool blk_get_queue(struct request_queue *q) | |
818 | { | |
819 | if (likely(!blk_queue_dying(q))) { | |
820 | __blk_get_queue(q); | |
821 | return true; | |
822 | } | |
823 | ||
824 | return false; | |
825 | } | |
826 | EXPORT_SYMBOL(blk_get_queue); | |
827 | ||
828 | static inline void blk_free_request(struct request_list *rl, struct request *rq) | |
829 | { | |
830 | if (rq->cmd_flags & REQ_ELVPRIV) { | |
831 | elv_put_request(rl->q, rq); | |
832 | if (rq->elv.icq) | |
833 | put_io_context(rq->elv.icq->ioc); | |
834 | } | |
835 | ||
836 | mempool_free(rq, rl->rq_pool); | |
837 | } | |
838 | ||
839 | /* | |
840 | * ioc_batching returns true if the ioc is a valid batching request and | |
841 | * should be given priority access to a request. | |
842 | */ | |
843 | static inline int ioc_batching(struct request_queue *q, struct io_context *ioc) | |
844 | { | |
845 | if (!ioc) | |
846 | return 0; | |
847 | ||
848 | /* | |
849 | * Make sure the process is able to allocate at least 1 request | |
850 | * even if the batch times out, otherwise we could theoretically | |
851 | * lose wakeups. | |
852 | */ | |
853 | return ioc->nr_batch_requests == q->nr_batching || | |
854 | (ioc->nr_batch_requests > 0 | |
855 | && time_before(jiffies, ioc->last_waited + BLK_BATCH_TIME)); | |
856 | } | |
857 | ||
858 | /* | |
859 | * ioc_set_batching sets ioc to be a new "batcher" if it is not one. This | |
860 | * will cause the process to be a "batcher" on all queues in the system. This | |
861 | * is the behaviour we want though - once it gets a wakeup it should be given | |
862 | * a nice run. | |
863 | */ | |
864 | static void ioc_set_batching(struct request_queue *q, struct io_context *ioc) | |
865 | { | |
866 | if (!ioc || ioc_batching(q, ioc)) | |
867 | return; | |
868 | ||
869 | ioc->nr_batch_requests = q->nr_batching; | |
870 | ioc->last_waited = jiffies; | |
871 | } | |
872 | ||
873 | static void __freed_request(struct request_list *rl, int sync) | |
874 | { | |
875 | struct request_queue *q = rl->q; | |
876 | ||
877 | if (rl->count[sync] < queue_congestion_off_threshold(q)) | |
878 | blk_clear_congested(rl, sync); | |
879 | ||
880 | if (rl->count[sync] + 1 <= q->nr_requests) { | |
881 | if (waitqueue_active(&rl->wait[sync])) | |
882 | wake_up(&rl->wait[sync]); | |
883 | ||
884 | blk_clear_rl_full(rl, sync); | |
885 | } | |
886 | } | |
887 | ||
888 | /* | |
889 | * A request has just been released. Account for it, update the full and | |
890 | * congestion status, wake up any waiters. Called under q->queue_lock. | |
891 | */ | |
892 | static void freed_request(struct request_list *rl, unsigned int flags) | |
893 | { | |
894 | struct request_queue *q = rl->q; | |
895 | int sync = rw_is_sync(flags); | |
896 | ||
897 | q->nr_rqs[sync]--; | |
898 | rl->count[sync]--; | |
899 | if (flags & REQ_ELVPRIV) | |
900 | q->nr_rqs_elvpriv--; | |
901 | ||
902 | __freed_request(rl, sync); | |
903 | ||
904 | if (unlikely(rl->starved[sync ^ 1])) | |
905 | __freed_request(rl, sync ^ 1); | |
906 | } | |
907 | ||
908 | int blk_update_nr_requests(struct request_queue *q, unsigned int nr) | |
909 | { | |
910 | struct request_list *rl; | |
911 | int on_thresh, off_thresh; | |
912 | ||
913 | spin_lock_irq(q->queue_lock); | |
914 | q->nr_requests = nr; | |
915 | blk_queue_congestion_threshold(q); | |
916 | on_thresh = queue_congestion_on_threshold(q); | |
917 | off_thresh = queue_congestion_off_threshold(q); | |
918 | ||
919 | blk_queue_for_each_rl(rl, q) { | |
920 | if (rl->count[BLK_RW_SYNC] >= on_thresh) | |
921 | blk_set_congested(rl, BLK_RW_SYNC); | |
922 | else if (rl->count[BLK_RW_SYNC] < off_thresh) | |
923 | blk_clear_congested(rl, BLK_RW_SYNC); | |
924 | ||
925 | if (rl->count[BLK_RW_ASYNC] >= on_thresh) | |
926 | blk_set_congested(rl, BLK_RW_ASYNC); | |
927 | else if (rl->count[BLK_RW_ASYNC] < off_thresh) | |
928 | blk_clear_congested(rl, BLK_RW_ASYNC); | |
929 | ||
930 | if (rl->count[BLK_RW_SYNC] >= q->nr_requests) { | |
931 | blk_set_rl_full(rl, BLK_RW_SYNC); | |
932 | } else { | |
933 | blk_clear_rl_full(rl, BLK_RW_SYNC); | |
934 | wake_up(&rl->wait[BLK_RW_SYNC]); | |
935 | } | |
936 | ||
937 | if (rl->count[BLK_RW_ASYNC] >= q->nr_requests) { | |
938 | blk_set_rl_full(rl, BLK_RW_ASYNC); | |
939 | } else { | |
940 | blk_clear_rl_full(rl, BLK_RW_ASYNC); | |
941 | wake_up(&rl->wait[BLK_RW_ASYNC]); | |
942 | } | |
943 | } | |
944 | ||
945 | spin_unlock_irq(q->queue_lock); | |
946 | return 0; | |
947 | } | |
948 | ||
949 | /* | |
950 | * Determine if elevator data should be initialized when allocating the | |
951 | * request associated with @bio. | |
952 | */ | |
953 | static bool blk_rq_should_init_elevator(struct bio *bio) | |
954 | { | |
955 | if (!bio) | |
956 | return true; | |
957 | ||
958 | /* | |
959 | * Flush requests do not use the elevator so skip initialization. | |
960 | * This allows a request to share the flush and elevator data. | |
961 | */ | |
962 | if (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) | |
963 | return false; | |
964 | ||
965 | return true; | |
966 | } | |
967 | ||
968 | /** | |
969 | * rq_ioc - determine io_context for request allocation | |
970 | * @bio: request being allocated is for this bio (can be %NULL) | |
971 | * | |
972 | * Determine io_context to use for request allocation for @bio. May return | |
973 | * %NULL if %current->io_context doesn't exist. | |
974 | */ | |
975 | static struct io_context *rq_ioc(struct bio *bio) | |
976 | { | |
977 | #ifdef CONFIG_BLK_CGROUP | |
978 | if (bio && bio->bi_ioc) | |
979 | return bio->bi_ioc; | |
980 | #endif | |
981 | return current->io_context; | |
982 | } | |
983 | ||
984 | /** | |
985 | * __get_request - get a free request | |
986 | * @rl: request list to allocate from | |
987 | * @rw_flags: RW and SYNC flags | |
988 | * @bio: bio to allocate request for (can be %NULL) | |
989 | * @gfp_mask: allocation mask | |
990 | * | |
991 | * Get a free request from @q. This function may fail under memory | |
992 | * pressure or if @q is dead. | |
993 | * | |
994 | * Must be called with @q->queue_lock held and, | |
995 | * Returns ERR_PTR on failure, with @q->queue_lock held. | |
996 | * Returns request pointer on success, with @q->queue_lock *not held*. | |
997 | */ | |
998 | static struct request *__get_request(struct request_list *rl, int rw_flags, | |
999 | struct bio *bio, gfp_t gfp_mask) | |
1000 | { | |
1001 | struct request_queue *q = rl->q; | |
1002 | struct request *rq; | |
1003 | struct elevator_type *et = q->elevator->type; | |
1004 | struct io_context *ioc = rq_ioc(bio); | |
1005 | struct io_cq *icq = NULL; | |
1006 | const bool is_sync = rw_is_sync(rw_flags) != 0; | |
1007 | int may_queue; | |
1008 | ||
1009 | if (unlikely(blk_queue_dying(q))) | |
1010 | return ERR_PTR(-ENODEV); | |
1011 | ||
1012 | may_queue = elv_may_queue(q, rw_flags); | |
1013 | if (may_queue == ELV_MQUEUE_NO) | |
1014 | goto rq_starved; | |
1015 | ||
1016 | if (rl->count[is_sync]+1 >= queue_congestion_on_threshold(q)) { | |
1017 | if (rl->count[is_sync]+1 >= q->nr_requests) { | |
1018 | /* | |
1019 | * The queue will fill after this allocation, so set | |
1020 | * it as full, and mark this process as "batching". | |
1021 | * This process will be allowed to complete a batch of | |
1022 | * requests, others will be blocked. | |
1023 | */ | |
1024 | if (!blk_rl_full(rl, is_sync)) { | |
1025 | ioc_set_batching(q, ioc); | |
1026 | blk_set_rl_full(rl, is_sync); | |
1027 | } else { | |
1028 | if (may_queue != ELV_MQUEUE_MUST | |
1029 | && !ioc_batching(q, ioc)) { | |
1030 | /* | |
1031 | * The queue is full and the allocating | |
1032 | * process is not a "batcher", and not | |
1033 | * exempted by the IO scheduler | |
1034 | */ | |
1035 | return ERR_PTR(-ENOMEM); | |
1036 | } | |
1037 | } | |
1038 | } | |
1039 | blk_set_congested(rl, is_sync); | |
1040 | } | |
1041 | ||
1042 | /* | |
1043 | * Only allow batching queuers to allocate up to 50% over the defined | |
1044 | * limit of requests, otherwise we could have thousands of requests | |
1045 | * allocated with any setting of ->nr_requests | |
1046 | */ | |
1047 | if (rl->count[is_sync] >= (3 * q->nr_requests / 2)) | |
1048 | return ERR_PTR(-ENOMEM); | |
1049 | ||
1050 | q->nr_rqs[is_sync]++; | |
1051 | rl->count[is_sync]++; | |
1052 | rl->starved[is_sync] = 0; | |
1053 | ||
1054 | /* | |
1055 | * Decide whether the new request will be managed by elevator. If | |
1056 | * so, mark @rw_flags and increment elvpriv. Non-zero elvpriv will | |
1057 | * prevent the current elevator from being destroyed until the new | |
1058 | * request is freed. This guarantees icq's won't be destroyed and | |
1059 | * makes creating new ones safe. | |
1060 | * | |
1061 | * Also, lookup icq while holding queue_lock. If it doesn't exist, | |
1062 | * it will be created after releasing queue_lock. | |
1063 | */ | |
1064 | if (blk_rq_should_init_elevator(bio) && !blk_queue_bypass(q)) { | |
1065 | rw_flags |= REQ_ELVPRIV; | |
1066 | q->nr_rqs_elvpriv++; | |
1067 | if (et->icq_cache && ioc) | |
1068 | icq = ioc_lookup_icq(ioc, q); | |
1069 | } | |
1070 | ||
1071 | if (blk_queue_io_stat(q)) | |
1072 | rw_flags |= REQ_IO_STAT; | |
1073 | spin_unlock_irq(q->queue_lock); | |
1074 | ||
1075 | /* allocate and init request */ | |
1076 | rq = mempool_alloc(rl->rq_pool, gfp_mask); | |
1077 | if (!rq) | |
1078 | goto fail_alloc; | |
1079 | ||
1080 | blk_rq_init(q, rq); | |
1081 | blk_rq_set_rl(rq, rl); | |
1082 | rq->cmd_flags = rw_flags | REQ_ALLOCED; | |
1083 | ||
1084 | /* init elvpriv */ | |
1085 | if (rw_flags & REQ_ELVPRIV) { | |
1086 | if (unlikely(et->icq_cache && !icq)) { | |
1087 | if (ioc) | |
1088 | icq = ioc_create_icq(ioc, q, gfp_mask); | |
1089 | if (!icq) | |
1090 | goto fail_elvpriv; | |
1091 | } | |
1092 | ||
1093 | rq->elv.icq = icq; | |
1094 | if (unlikely(elv_set_request(q, rq, bio, gfp_mask))) | |
1095 | goto fail_elvpriv; | |
1096 | ||
1097 | /* @rq->elv.icq holds io_context until @rq is freed */ | |
1098 | if (icq) | |
1099 | get_io_context(icq->ioc); | |
1100 | } | |
1101 | out: | |
1102 | /* | |
1103 | * ioc may be NULL here, and ioc_batching will be false. That's | |
1104 | * OK, if the queue is under the request limit then requests need | |
1105 | * not count toward the nr_batch_requests limit. There will always | |
1106 | * be some limit enforced by BLK_BATCH_TIME. | |
1107 | */ | |
1108 | if (ioc_batching(q, ioc)) | |
1109 | ioc->nr_batch_requests--; | |
1110 | ||
1111 | trace_block_getrq(q, bio, rw_flags & 1); | |
1112 | return rq; | |
1113 | ||
1114 | fail_elvpriv: | |
1115 | /* | |
1116 | * elvpriv init failed. ioc, icq and elvpriv aren't mempool backed | |
1117 | * and may fail indefinitely under memory pressure and thus | |
1118 | * shouldn't stall IO. Treat this request as !elvpriv. This will | |
1119 | * disturb iosched and blkcg but weird is bettern than dead. | |
1120 | */ | |
1121 | printk_ratelimited(KERN_WARNING "%s: dev %s: request aux data allocation failed, iosched may be disturbed\n", | |
1122 | __func__, dev_name(q->backing_dev_info.dev)); | |
1123 | ||
1124 | rq->cmd_flags &= ~REQ_ELVPRIV; | |
1125 | rq->elv.icq = NULL; | |
1126 | ||
1127 | spin_lock_irq(q->queue_lock); | |
1128 | q->nr_rqs_elvpriv--; | |
1129 | spin_unlock_irq(q->queue_lock); | |
1130 | goto out; | |
1131 | ||
1132 | fail_alloc: | |
1133 | /* | |
1134 | * Allocation failed presumably due to memory. Undo anything we | |
1135 | * might have messed up. | |
1136 | * | |
1137 | * Allocating task should really be put onto the front of the wait | |
1138 | * queue, but this is pretty rare. | |
1139 | */ | |
1140 | spin_lock_irq(q->queue_lock); | |
1141 | freed_request(rl, rw_flags); | |
1142 | ||
1143 | /* | |
1144 | * in the very unlikely event that allocation failed and no | |
1145 | * requests for this direction was pending, mark us starved so that | |
1146 | * freeing of a request in the other direction will notice | |
1147 | * us. another possible fix would be to split the rq mempool into | |
1148 | * READ and WRITE | |
1149 | */ | |
1150 | rq_starved: | |
1151 | if (unlikely(rl->count[is_sync] == 0)) | |
1152 | rl->starved[is_sync] = 1; | |
1153 | return ERR_PTR(-ENOMEM); | |
1154 | } | |
1155 | ||
1156 | /** | |
1157 | * get_request - get a free request | |
1158 | * @q: request_queue to allocate request from | |
1159 | * @rw_flags: RW and SYNC flags | |
1160 | * @bio: bio to allocate request for (can be %NULL) | |
1161 | * @gfp_mask: allocation mask | |
1162 | * | |
1163 | * Get a free request from @q. If %__GFP_WAIT is set in @gfp_mask, this | |
1164 | * function keeps retrying under memory pressure and fails iff @q is dead. | |
1165 | * | |
1166 | * Must be called with @q->queue_lock held and, | |
1167 | * Returns ERR_PTR on failure, with @q->queue_lock held. | |
1168 | * Returns request pointer on success, with @q->queue_lock *not held*. | |
1169 | */ | |
1170 | static struct request *get_request(struct request_queue *q, int rw_flags, | |
1171 | struct bio *bio, gfp_t gfp_mask) | |
1172 | { | |
1173 | const bool is_sync = rw_is_sync(rw_flags) != 0; | |
1174 | DEFINE_WAIT(wait); | |
1175 | struct request_list *rl; | |
1176 | struct request *rq; | |
1177 | ||
1178 | rl = blk_get_rl(q, bio); /* transferred to @rq on success */ | |
1179 | retry: | |
1180 | rq = __get_request(rl, rw_flags, bio, gfp_mask); | |
1181 | if (!IS_ERR(rq)) | |
1182 | return rq; | |
1183 | ||
1184 | if (!(gfp_mask & __GFP_WAIT) || unlikely(blk_queue_dying(q))) { | |
1185 | blk_put_rl(rl); | |
1186 | return rq; | |
1187 | } | |
1188 | ||
1189 | /* wait on @rl and retry */ | |
1190 | prepare_to_wait_exclusive(&rl->wait[is_sync], &wait, | |
1191 | TASK_UNINTERRUPTIBLE); | |
1192 | ||
1193 | trace_block_sleeprq(q, bio, rw_flags & 1); | |
1194 | ||
1195 | spin_unlock_irq(q->queue_lock); | |
1196 | io_schedule(); | |
1197 | ||
1198 | /* | |
1199 | * After sleeping, we become a "batching" process and will be able | |
1200 | * to allocate at least one request, and up to a big batch of them | |
1201 | * for a small period time. See ioc_batching, ioc_set_batching | |
1202 | */ | |
1203 | ioc_set_batching(q, current->io_context); | |
1204 | ||
1205 | spin_lock_irq(q->queue_lock); | |
1206 | finish_wait(&rl->wait[is_sync], &wait); | |
1207 | ||
1208 | goto retry; | |
1209 | } | |
1210 | ||
1211 | static struct request *blk_old_get_request(struct request_queue *q, int rw, | |
1212 | gfp_t gfp_mask) | |
1213 | { | |
1214 | struct request *rq; | |
1215 | ||
1216 | BUG_ON(rw != READ && rw != WRITE); | |
1217 | ||
1218 | /* create ioc upfront */ | |
1219 | create_io_context(gfp_mask, q->node); | |
1220 | ||
1221 | spin_lock_irq(q->queue_lock); | |
1222 | rq = get_request(q, rw, NULL, gfp_mask); | |
1223 | if (IS_ERR(rq)) | |
1224 | spin_unlock_irq(q->queue_lock); | |
1225 | /* q->queue_lock is unlocked at this point */ | |
1226 | ||
1227 | return rq; | |
1228 | } | |
1229 | ||
1230 | struct request *blk_get_request(struct request_queue *q, int rw, gfp_t gfp_mask) | |
1231 | { | |
1232 | if (q->mq_ops) | |
1233 | return blk_mq_alloc_request(q, rw, gfp_mask, false); | |
1234 | else | |
1235 | return blk_old_get_request(q, rw, gfp_mask); | |
1236 | } | |
1237 | EXPORT_SYMBOL(blk_get_request); | |
1238 | ||
1239 | /** | |
1240 | * blk_make_request - given a bio, allocate a corresponding struct request. | |
1241 | * @q: target request queue | |
1242 | * @bio: The bio describing the memory mappings that will be submitted for IO. | |
1243 | * It may be a chained-bio properly constructed by block/bio layer. | |
1244 | * @gfp_mask: gfp flags to be used for memory allocation | |
1245 | * | |
1246 | * blk_make_request is the parallel of generic_make_request for BLOCK_PC | |
1247 | * type commands. Where the struct request needs to be farther initialized by | |
1248 | * the caller. It is passed a &struct bio, which describes the memory info of | |
1249 | * the I/O transfer. | |
1250 | * | |
1251 | * The caller of blk_make_request must make sure that bi_io_vec | |
1252 | * are set to describe the memory buffers. That bio_data_dir() will return | |
1253 | * the needed direction of the request. (And all bio's in the passed bio-chain | |
1254 | * are properly set accordingly) | |
1255 | * | |
1256 | * If called under none-sleepable conditions, mapped bio buffers must not | |
1257 | * need bouncing, by calling the appropriate masked or flagged allocator, | |
1258 | * suitable for the target device. Otherwise the call to blk_queue_bounce will | |
1259 | * BUG. | |
1260 | * | |
1261 | * WARNING: When allocating/cloning a bio-chain, careful consideration should be | |
1262 | * given to how you allocate bios. In particular, you cannot use __GFP_WAIT for | |
1263 | * anything but the first bio in the chain. Otherwise you risk waiting for IO | |
1264 | * completion of a bio that hasn't been submitted yet, thus resulting in a | |
1265 | * deadlock. Alternatively bios should be allocated using bio_kmalloc() instead | |
1266 | * of bio_alloc(), as that avoids the mempool deadlock. | |
1267 | * If possible a big IO should be split into smaller parts when allocation | |
1268 | * fails. Partial allocation should not be an error, or you risk a live-lock. | |
1269 | */ | |
1270 | struct request *blk_make_request(struct request_queue *q, struct bio *bio, | |
1271 | gfp_t gfp_mask) | |
1272 | { | |
1273 | struct request *rq = blk_get_request(q, bio_data_dir(bio), gfp_mask); | |
1274 | ||
1275 | if (IS_ERR(rq)) | |
1276 | return rq; | |
1277 | ||
1278 | blk_rq_set_block_pc(rq); | |
1279 | ||
1280 | for_each_bio(bio) { | |
1281 | struct bio *bounce_bio = bio; | |
1282 | int ret; | |
1283 | ||
1284 | blk_queue_bounce(q, &bounce_bio); | |
1285 | ret = blk_rq_append_bio(q, rq, bounce_bio); | |
1286 | if (unlikely(ret)) { | |
1287 | blk_put_request(rq); | |
1288 | return ERR_PTR(ret); | |
1289 | } | |
1290 | } | |
1291 | ||
1292 | return rq; | |
1293 | } | |
1294 | EXPORT_SYMBOL(blk_make_request); | |
1295 | ||
1296 | /** | |
1297 | * blk_rq_set_block_pc - initialize a request to type BLOCK_PC | |
1298 | * @rq: request to be initialized | |
1299 | * | |
1300 | */ | |
1301 | void blk_rq_set_block_pc(struct request *rq) | |
1302 | { | |
1303 | rq->cmd_type = REQ_TYPE_BLOCK_PC; | |
1304 | rq->__data_len = 0; | |
1305 | rq->__sector = (sector_t) -1; | |
1306 | rq->bio = rq->biotail = NULL; | |
1307 | memset(rq->__cmd, 0, sizeof(rq->__cmd)); | |
1308 | } | |
1309 | EXPORT_SYMBOL(blk_rq_set_block_pc); | |
1310 | ||
1311 | /** | |
1312 | * blk_requeue_request - put a request back on queue | |
1313 | * @q: request queue where request should be inserted | |
1314 | * @rq: request to be inserted | |
1315 | * | |
1316 | * Description: | |
1317 | * Drivers often keep queueing requests until the hardware cannot accept | |
1318 | * more, when that condition happens we need to put the request back | |
1319 | * on the queue. Must be called with queue lock held. | |
1320 | */ | |
1321 | void blk_requeue_request(struct request_queue *q, struct request *rq) | |
1322 | { | |
1323 | blk_delete_timer(rq); | |
1324 | blk_clear_rq_complete(rq); | |
1325 | trace_block_rq_requeue(q, rq); | |
1326 | ||
1327 | if (rq->cmd_flags & REQ_QUEUED) | |
1328 | blk_queue_end_tag(q, rq); | |
1329 | ||
1330 | BUG_ON(blk_queued_rq(rq)); | |
1331 | ||
1332 | elv_requeue_request(q, rq); | |
1333 | } | |
1334 | EXPORT_SYMBOL(blk_requeue_request); | |
1335 | ||
1336 | static void add_acct_request(struct request_queue *q, struct request *rq, | |
1337 | int where) | |
1338 | { | |
1339 | blk_account_io_start(rq, true); | |
1340 | __elv_add_request(q, rq, where); | |
1341 | } | |
1342 | ||
1343 | static void part_round_stats_single(int cpu, struct hd_struct *part, | |
1344 | unsigned long now) | |
1345 | { | |
1346 | int inflight; | |
1347 | ||
1348 | if (now == part->stamp) | |
1349 | return; | |
1350 | ||
1351 | inflight = part_in_flight(part); | |
1352 | if (inflight) { | |
1353 | __part_stat_add(cpu, part, time_in_queue, | |
1354 | inflight * (now - part->stamp)); | |
1355 | __part_stat_add(cpu, part, io_ticks, (now - part->stamp)); | |
1356 | } | |
1357 | part->stamp = now; | |
1358 | } | |
1359 | ||
1360 | /** | |
1361 | * part_round_stats() - Round off the performance stats on a struct disk_stats. | |
1362 | * @cpu: cpu number for stats access | |
1363 | * @part: target partition | |
1364 | * | |
1365 | * The average IO queue length and utilisation statistics are maintained | |
1366 | * by observing the current state of the queue length and the amount of | |
1367 | * time it has been in this state for. | |
1368 | * | |
1369 | * Normally, that accounting is done on IO completion, but that can result | |
1370 | * in more than a second's worth of IO being accounted for within any one | |
1371 | * second, leading to >100% utilisation. To deal with that, we call this | |
1372 | * function to do a round-off before returning the results when reading | |
1373 | * /proc/diskstats. This accounts immediately for all queue usage up to | |
1374 | * the current jiffies and restarts the counters again. | |
1375 | */ | |
1376 | void part_round_stats(int cpu, struct hd_struct *part) | |
1377 | { | |
1378 | unsigned long now = jiffies; | |
1379 | ||
1380 | if (part->partno) | |
1381 | part_round_stats_single(cpu, &part_to_disk(part)->part0, now); | |
1382 | part_round_stats_single(cpu, part, now); | |
1383 | } | |
1384 | EXPORT_SYMBOL_GPL(part_round_stats); | |
1385 | ||
1386 | #ifdef CONFIG_PM | |
1387 | static void blk_pm_put_request(struct request *rq) | |
1388 | { | |
1389 | if (rq->q->dev && !(rq->cmd_flags & REQ_PM) && !--rq->q->nr_pending) | |
1390 | pm_runtime_mark_last_busy(rq->q->dev); | |
1391 | } | |
1392 | #else | |
1393 | static inline void blk_pm_put_request(struct request *rq) {} | |
1394 | #endif | |
1395 | ||
1396 | /* | |
1397 | * queue lock must be held | |
1398 | */ | |
1399 | void __blk_put_request(struct request_queue *q, struct request *req) | |
1400 | { | |
1401 | if (unlikely(!q)) | |
1402 | return; | |
1403 | ||
1404 | if (q->mq_ops) { | |
1405 | blk_mq_free_request(req); | |
1406 | return; | |
1407 | } | |
1408 | ||
1409 | blk_pm_put_request(req); | |
1410 | ||
1411 | elv_completed_request(q, req); | |
1412 | ||
1413 | /* this is a bio leak */ | |
1414 | WARN_ON(req->bio != NULL); | |
1415 | ||
1416 | /* | |
1417 | * Request may not have originated from ll_rw_blk. if not, | |
1418 | * it didn't come out of our reserved rq pools | |
1419 | */ | |
1420 | if (req->cmd_flags & REQ_ALLOCED) { | |
1421 | unsigned int flags = req->cmd_flags; | |
1422 | struct request_list *rl = blk_rq_rl(req); | |
1423 | ||
1424 | BUG_ON(!list_empty(&req->queuelist)); | |
1425 | BUG_ON(ELV_ON_HASH(req)); | |
1426 | ||
1427 | blk_free_request(rl, req); | |
1428 | freed_request(rl, flags); | |
1429 | blk_put_rl(rl); | |
1430 | } | |
1431 | } | |
1432 | EXPORT_SYMBOL_GPL(__blk_put_request); | |
1433 | ||
1434 | void blk_put_request(struct request *req) | |
1435 | { | |
1436 | struct request_queue *q = req->q; | |
1437 | ||
1438 | if (q->mq_ops) | |
1439 | blk_mq_free_request(req); | |
1440 | else { | |
1441 | unsigned long flags; | |
1442 | ||
1443 | spin_lock_irqsave(q->queue_lock, flags); | |
1444 | __blk_put_request(q, req); | |
1445 | spin_unlock_irqrestore(q->queue_lock, flags); | |
1446 | } | |
1447 | } | |
1448 | EXPORT_SYMBOL(blk_put_request); | |
1449 | ||
1450 | /** | |
1451 | * blk_add_request_payload - add a payload to a request | |
1452 | * @rq: request to update | |
1453 | * @page: page backing the payload | |
1454 | * @len: length of the payload. | |
1455 | * | |
1456 | * This allows to later add a payload to an already submitted request by | |
1457 | * a block driver. The driver needs to take care of freeing the payload | |
1458 | * itself. | |
1459 | * | |
1460 | * Note that this is a quite horrible hack and nothing but handling of | |
1461 | * discard requests should ever use it. | |
1462 | */ | |
1463 | void blk_add_request_payload(struct request *rq, struct page *page, | |
1464 | unsigned int len) | |
1465 | { | |
1466 | struct bio *bio = rq->bio; | |
1467 | ||
1468 | bio->bi_io_vec->bv_page = page; | |
1469 | bio->bi_io_vec->bv_offset = 0; | |
1470 | bio->bi_io_vec->bv_len = len; | |
1471 | ||
1472 | bio->bi_iter.bi_size = len; | |
1473 | bio->bi_vcnt = 1; | |
1474 | bio->bi_phys_segments = 1; | |
1475 | ||
1476 | rq->__data_len = rq->resid_len = len; | |
1477 | rq->nr_phys_segments = 1; | |
1478 | } | |
1479 | EXPORT_SYMBOL_GPL(blk_add_request_payload); | |
1480 | ||
1481 | bool bio_attempt_back_merge(struct request_queue *q, struct request *req, | |
1482 | struct bio *bio) | |
1483 | { | |
1484 | const int ff = bio->bi_rw & REQ_FAILFAST_MASK; | |
1485 | ||
1486 | if (!ll_back_merge_fn(q, req, bio)) | |
1487 | return false; | |
1488 | ||
1489 | trace_block_bio_backmerge(q, req, bio); | |
1490 | ||
1491 | if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff) | |
1492 | blk_rq_set_mixed_merge(req); | |
1493 | ||
1494 | req->biotail->bi_next = bio; | |
1495 | req->biotail = bio; | |
1496 | req->__data_len += bio->bi_iter.bi_size; | |
1497 | req->ioprio = ioprio_best(req->ioprio, bio_prio(bio)); | |
1498 | ||
1499 | blk_account_io_start(req, false); | |
1500 | return true; | |
1501 | } | |
1502 | ||
1503 | bool bio_attempt_front_merge(struct request_queue *q, struct request *req, | |
1504 | struct bio *bio) | |
1505 | { | |
1506 | const int ff = bio->bi_rw & REQ_FAILFAST_MASK; | |
1507 | ||
1508 | if (!ll_front_merge_fn(q, req, bio)) | |
1509 | return false; | |
1510 | ||
1511 | trace_block_bio_frontmerge(q, req, bio); | |
1512 | ||
1513 | if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff) | |
1514 | blk_rq_set_mixed_merge(req); | |
1515 | ||
1516 | bio->bi_next = req->bio; | |
1517 | req->bio = bio; | |
1518 | ||
1519 | req->__sector = bio->bi_iter.bi_sector; | |
1520 | req->__data_len += bio->bi_iter.bi_size; | |
1521 | req->ioprio = ioprio_best(req->ioprio, bio_prio(bio)); | |
1522 | ||
1523 | blk_account_io_start(req, false); | |
1524 | return true; | |
1525 | } | |
1526 | ||
1527 | /** | |
1528 | * blk_attempt_plug_merge - try to merge with %current's plugged list | |
1529 | * @q: request_queue new bio is being queued at | |
1530 | * @bio: new bio being queued | |
1531 | * @request_count: out parameter for number of traversed plugged requests | |
1532 | * | |
1533 | * Determine whether @bio being queued on @q can be merged with a request | |
1534 | * on %current's plugged list. Returns %true if merge was successful, | |
1535 | * otherwise %false. | |
1536 | * | |
1537 | * Plugging coalesces IOs from the same issuer for the same purpose without | |
1538 | * going through @q->queue_lock. As such it's more of an issuing mechanism | |
1539 | * than scheduling, and the request, while may have elvpriv data, is not | |
1540 | * added on the elevator at this point. In addition, we don't have | |
1541 | * reliable access to the elevator outside queue lock. Only check basic | |
1542 | * merging parameters without querying the elevator. | |
1543 | * | |
1544 | * Caller must ensure !blk_queue_nomerges(q) beforehand. | |
1545 | */ | |
1546 | bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio, | |
1547 | unsigned int *request_count, | |
1548 | struct request **same_queue_rq) | |
1549 | { | |
1550 | struct blk_plug *plug; | |
1551 | struct request *rq; | |
1552 | bool ret = false; | |
1553 | struct list_head *plug_list; | |
1554 | ||
1555 | plug = current->plug; | |
1556 | if (!plug) | |
1557 | goto out; | |
1558 | *request_count = 0; | |
1559 | ||
1560 | if (q->mq_ops) | |
1561 | plug_list = &plug->mq_list; | |
1562 | else | |
1563 | plug_list = &plug->list; | |
1564 | ||
1565 | list_for_each_entry_reverse(rq, plug_list, queuelist) { | |
1566 | int el_ret; | |
1567 | ||
1568 | if (rq->q == q) { | |
1569 | (*request_count)++; | |
1570 | /* | |
1571 | * Only blk-mq multiple hardware queues case checks the | |
1572 | * rq in the same queue, there should be only one such | |
1573 | * rq in a queue | |
1574 | **/ | |
1575 | if (same_queue_rq) | |
1576 | *same_queue_rq = rq; | |
1577 | } | |
1578 | ||
1579 | if (rq->q != q || !blk_rq_merge_ok(rq, bio)) | |
1580 | continue; | |
1581 | ||
1582 | el_ret = blk_try_merge(rq, bio); | |
1583 | if (el_ret == ELEVATOR_BACK_MERGE) { | |
1584 | ret = bio_attempt_back_merge(q, rq, bio); | |
1585 | if (ret) | |
1586 | break; | |
1587 | } else if (el_ret == ELEVATOR_FRONT_MERGE) { | |
1588 | ret = bio_attempt_front_merge(q, rq, bio); | |
1589 | if (ret) | |
1590 | break; | |
1591 | } | |
1592 | } | |
1593 | out: | |
1594 | return ret; | |
1595 | } | |
1596 | ||
1597 | void init_request_from_bio(struct request *req, struct bio *bio) | |
1598 | { | |
1599 | req->cmd_type = REQ_TYPE_FS; | |
1600 | ||
1601 | req->cmd_flags |= bio->bi_rw & REQ_COMMON_MASK; | |
1602 | if (bio->bi_rw & REQ_RAHEAD) | |
1603 | req->cmd_flags |= REQ_FAILFAST_MASK; | |
1604 | ||
1605 | req->errors = 0; | |
1606 | req->__sector = bio->bi_iter.bi_sector; | |
1607 | req->ioprio = bio_prio(bio); | |
1608 | blk_rq_bio_prep(req->q, req, bio); | |
1609 | } | |
1610 | ||
1611 | static void blk_queue_bio(struct request_queue *q, struct bio *bio) | |
1612 | { | |
1613 | const bool sync = !!(bio->bi_rw & REQ_SYNC); | |
1614 | struct blk_plug *plug; | |
1615 | int el_ret, rw_flags, where = ELEVATOR_INSERT_SORT; | |
1616 | struct request *req; | |
1617 | unsigned int request_count = 0; | |
1618 | ||
1619 | blk_queue_split(q, &bio, q->bio_split); | |
1620 | ||
1621 | /* | |
1622 | * low level driver can indicate that it wants pages above a | |
1623 | * certain limit bounced to low memory (ie for highmem, or even | |
1624 | * ISA dma in theory) | |
1625 | */ | |
1626 | blk_queue_bounce(q, &bio); | |
1627 | ||
1628 | if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) { | |
1629 | bio->bi_error = -EIO; | |
1630 | bio_endio(bio); | |
1631 | return; | |
1632 | } | |
1633 | ||
1634 | if (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) { | |
1635 | spin_lock_irq(q->queue_lock); | |
1636 | where = ELEVATOR_INSERT_FLUSH; | |
1637 | goto get_rq; | |
1638 | } | |
1639 | ||
1640 | /* | |
1641 | * Check if we can merge with the plugged list before grabbing | |
1642 | * any locks. | |
1643 | */ | |
1644 | if (!blk_queue_nomerges(q) && | |
1645 | blk_attempt_plug_merge(q, bio, &request_count, NULL)) | |
1646 | return; | |
1647 | ||
1648 | spin_lock_irq(q->queue_lock); | |
1649 | ||
1650 | el_ret = elv_merge(q, &req, bio); | |
1651 | if (el_ret == ELEVATOR_BACK_MERGE) { | |
1652 | if (bio_attempt_back_merge(q, req, bio)) { | |
1653 | elv_bio_merged(q, req, bio); | |
1654 | if (!attempt_back_merge(q, req)) | |
1655 | elv_merged_request(q, req, el_ret); | |
1656 | goto out_unlock; | |
1657 | } | |
1658 | } else if (el_ret == ELEVATOR_FRONT_MERGE) { | |
1659 | if (bio_attempt_front_merge(q, req, bio)) { | |
1660 | elv_bio_merged(q, req, bio); | |
1661 | if (!attempt_front_merge(q, req)) | |
1662 | elv_merged_request(q, req, el_ret); | |
1663 | goto out_unlock; | |
1664 | } | |
1665 | } | |
1666 | ||
1667 | get_rq: | |
1668 | /* | |
1669 | * This sync check and mask will be re-done in init_request_from_bio(), | |
1670 | * but we need to set it earlier to expose the sync flag to the | |
1671 | * rq allocator and io schedulers. | |
1672 | */ | |
1673 | rw_flags = bio_data_dir(bio); | |
1674 | if (sync) | |
1675 | rw_flags |= REQ_SYNC; | |
1676 | ||
1677 | /* | |
1678 | * Grab a free request. This is might sleep but can not fail. | |
1679 | * Returns with the queue unlocked. | |
1680 | */ | |
1681 | req = get_request(q, rw_flags, bio, GFP_NOIO); | |
1682 | if (IS_ERR(req)) { | |
1683 | bio->bi_error = PTR_ERR(req); | |
1684 | bio_endio(bio); | |
1685 | goto out_unlock; | |
1686 | } | |
1687 | ||
1688 | /* | |
1689 | * After dropping the lock and possibly sleeping here, our request | |
1690 | * may now be mergeable after it had proven unmergeable (above). | |
1691 | * We don't worry about that case for efficiency. It won't happen | |
1692 | * often, and the elevators are able to handle it. | |
1693 | */ | |
1694 | init_request_from_bio(req, bio); | |
1695 | ||
1696 | if (test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags)) | |
1697 | req->cpu = raw_smp_processor_id(); | |
1698 | ||
1699 | plug = current->plug; | |
1700 | if (plug) { | |
1701 | /* | |
1702 | * If this is the first request added after a plug, fire | |
1703 | * of a plug trace. | |
1704 | */ | |
1705 | if (!request_count) | |
1706 | trace_block_plug(q); | |
1707 | else { | |
1708 | if (request_count >= BLK_MAX_REQUEST_COUNT) { | |
1709 | blk_flush_plug_list(plug, false); | |
1710 | trace_block_plug(q); | |
1711 | } | |
1712 | } | |
1713 | list_add_tail(&req->queuelist, &plug->list); | |
1714 | blk_account_io_start(req, true); | |
1715 | } else { | |
1716 | spin_lock_irq(q->queue_lock); | |
1717 | add_acct_request(q, req, where); | |
1718 | __blk_run_queue(q); | |
1719 | out_unlock: | |
1720 | spin_unlock_irq(q->queue_lock); | |
1721 | } | |
1722 | } | |
1723 | ||
1724 | /* | |
1725 | * If bio->bi_dev is a partition, remap the location | |
1726 | */ | |
1727 | static inline void blk_partition_remap(struct bio *bio) | |
1728 | { | |
1729 | struct block_device *bdev = bio->bi_bdev; | |
1730 | ||
1731 | if (bio_sectors(bio) && bdev != bdev->bd_contains) { | |
1732 | struct hd_struct *p = bdev->bd_part; | |
1733 | ||
1734 | bio->bi_iter.bi_sector += p->start_sect; | |
1735 | bio->bi_bdev = bdev->bd_contains; | |
1736 | ||
1737 | trace_block_bio_remap(bdev_get_queue(bio->bi_bdev), bio, | |
1738 | bdev->bd_dev, | |
1739 | bio->bi_iter.bi_sector - p->start_sect); | |
1740 | } | |
1741 | } | |
1742 | ||
1743 | static void handle_bad_sector(struct bio *bio) | |
1744 | { | |
1745 | char b[BDEVNAME_SIZE]; | |
1746 | ||
1747 | printk(KERN_INFO "attempt to access beyond end of device\n"); | |
1748 | printk(KERN_INFO "%s: rw=%ld, want=%Lu, limit=%Lu\n", | |
1749 | bdevname(bio->bi_bdev, b), | |
1750 | bio->bi_rw, | |
1751 | (unsigned long long)bio_end_sector(bio), | |
1752 | (long long)(i_size_read(bio->bi_bdev->bd_inode) >> 9)); | |
1753 | } | |
1754 | ||
1755 | #ifdef CONFIG_FAIL_MAKE_REQUEST | |
1756 | ||
1757 | static DECLARE_FAULT_ATTR(fail_make_request); | |
1758 | ||
1759 | static int __init setup_fail_make_request(char *str) | |
1760 | { | |
1761 | return setup_fault_attr(&fail_make_request, str); | |
1762 | } | |
1763 | __setup("fail_make_request=", setup_fail_make_request); | |
1764 | ||
1765 | static bool should_fail_request(struct hd_struct *part, unsigned int bytes) | |
1766 | { | |
1767 | return part->make_it_fail && should_fail(&fail_make_request, bytes); | |
1768 | } | |
1769 | ||
1770 | static int __init fail_make_request_debugfs(void) | |
1771 | { | |
1772 | struct dentry *dir = fault_create_debugfs_attr("fail_make_request", | |
1773 | NULL, &fail_make_request); | |
1774 | ||
1775 | return PTR_ERR_OR_ZERO(dir); | |
1776 | } | |
1777 | ||
1778 | late_initcall(fail_make_request_debugfs); | |
1779 | ||
1780 | #else /* CONFIG_FAIL_MAKE_REQUEST */ | |
1781 | ||
1782 | static inline bool should_fail_request(struct hd_struct *part, | |
1783 | unsigned int bytes) | |
1784 | { | |
1785 | return false; | |
1786 | } | |
1787 | ||
1788 | #endif /* CONFIG_FAIL_MAKE_REQUEST */ | |
1789 | ||
1790 | /* | |
1791 | * Check whether this bio extends beyond the end of the device. | |
1792 | */ | |
1793 | static inline int bio_check_eod(struct bio *bio, unsigned int nr_sectors) | |
1794 | { | |
1795 | sector_t maxsector; | |
1796 | ||
1797 | if (!nr_sectors) | |
1798 | return 0; | |
1799 | ||
1800 | /* Test device or partition size, when known. */ | |
1801 | maxsector = i_size_read(bio->bi_bdev->bd_inode) >> 9; | |
1802 | if (maxsector) { | |
1803 | sector_t sector = bio->bi_iter.bi_sector; | |
1804 | ||
1805 | if (maxsector < nr_sectors || maxsector - nr_sectors < sector) { | |
1806 | /* | |
1807 | * This may well happen - the kernel calls bread() | |
1808 | * without checking the size of the device, e.g., when | |
1809 | * mounting a device. | |
1810 | */ | |
1811 | handle_bad_sector(bio); | |
1812 | return 1; | |
1813 | } | |
1814 | } | |
1815 | ||
1816 | return 0; | |
1817 | } | |
1818 | ||
1819 | static noinline_for_stack bool | |
1820 | generic_make_request_checks(struct bio *bio) | |
1821 | { | |
1822 | struct request_queue *q; | |
1823 | int nr_sectors = bio_sectors(bio); | |
1824 | int err = -EIO; | |
1825 | char b[BDEVNAME_SIZE]; | |
1826 | struct hd_struct *part; | |
1827 | ||
1828 | might_sleep(); | |
1829 | ||
1830 | if (bio_check_eod(bio, nr_sectors)) | |
1831 | goto end_io; | |
1832 | ||
1833 | q = bdev_get_queue(bio->bi_bdev); | |
1834 | if (unlikely(!q)) { | |
1835 | printk(KERN_ERR | |
1836 | "generic_make_request: Trying to access " | |
1837 | "nonexistent block-device %s (%Lu)\n", | |
1838 | bdevname(bio->bi_bdev, b), | |
1839 | (long long) bio->bi_iter.bi_sector); | |
1840 | goto end_io; | |
1841 | } | |
1842 | ||
1843 | part = bio->bi_bdev->bd_part; | |
1844 | if (should_fail_request(part, bio->bi_iter.bi_size) || | |
1845 | should_fail_request(&part_to_disk(part)->part0, | |
1846 | bio->bi_iter.bi_size)) | |
1847 | goto end_io; | |
1848 | ||
1849 | /* | |
1850 | * If this device has partitions, remap block n | |
1851 | * of partition p to block n+start(p) of the disk. | |
1852 | */ | |
1853 | blk_partition_remap(bio); | |
1854 | ||
1855 | if (bio_check_eod(bio, nr_sectors)) | |
1856 | goto end_io; | |
1857 | ||
1858 | /* | |
1859 | * Filter flush bio's early so that make_request based | |
1860 | * drivers without flush support don't have to worry | |
1861 | * about them. | |
1862 | */ | |
1863 | if ((bio->bi_rw & (REQ_FLUSH | REQ_FUA)) && !q->flush_flags) { | |
1864 | bio->bi_rw &= ~(REQ_FLUSH | REQ_FUA); | |
1865 | if (!nr_sectors) { | |
1866 | err = 0; | |
1867 | goto end_io; | |
1868 | } | |
1869 | } | |
1870 | ||
1871 | if ((bio->bi_rw & REQ_DISCARD) && | |
1872 | (!blk_queue_discard(q) || | |
1873 | ((bio->bi_rw & REQ_SECURE) && !blk_queue_secdiscard(q)))) { | |
1874 | err = -EOPNOTSUPP; | |
1875 | goto end_io; | |
1876 | } | |
1877 | ||
1878 | if (bio->bi_rw & REQ_WRITE_SAME && !bdev_write_same(bio->bi_bdev)) { | |
1879 | err = -EOPNOTSUPP; | |
1880 | goto end_io; | |
1881 | } | |
1882 | ||
1883 | /* | |
1884 | * Various block parts want %current->io_context and lazy ioc | |
1885 | * allocation ends up trading a lot of pain for a small amount of | |
1886 | * memory. Just allocate it upfront. This may fail and block | |
1887 | * layer knows how to live with it. | |
1888 | */ | |
1889 | create_io_context(GFP_ATOMIC, q->node); | |
1890 | ||
1891 | if (!blkcg_bio_issue_check(q, bio)) | |
1892 | return false; | |
1893 | ||
1894 | trace_block_bio_queue(q, bio); | |
1895 | return true; | |
1896 | ||
1897 | end_io: | |
1898 | bio->bi_error = err; | |
1899 | bio_endio(bio); | |
1900 | return false; | |
1901 | } | |
1902 | ||
1903 | /** | |
1904 | * generic_make_request - hand a buffer to its device driver for I/O | |
1905 | * @bio: The bio describing the location in memory and on the device. | |
1906 | * | |
1907 | * generic_make_request() is used to make I/O requests of block | |
1908 | * devices. It is passed a &struct bio, which describes the I/O that needs | |
1909 | * to be done. | |
1910 | * | |
1911 | * generic_make_request() does not return any status. The | |
1912 | * success/failure status of the request, along with notification of | |
1913 | * completion, is delivered asynchronously through the bio->bi_end_io | |
1914 | * function described (one day) else where. | |
1915 | * | |
1916 | * The caller of generic_make_request must make sure that bi_io_vec | |
1917 | * are set to describe the memory buffer, and that bi_dev and bi_sector are | |
1918 | * set to describe the device address, and the | |
1919 | * bi_end_io and optionally bi_private are set to describe how | |
1920 | * completion notification should be signaled. | |
1921 | * | |
1922 | * generic_make_request and the drivers it calls may use bi_next if this | |
1923 | * bio happens to be merged with someone else, and may resubmit the bio to | |
1924 | * a lower device by calling into generic_make_request recursively, which | |
1925 | * means the bio should NOT be touched after the call to ->make_request_fn. | |
1926 | */ | |
1927 | void generic_make_request(struct bio *bio) | |
1928 | { | |
1929 | struct bio_list bio_list_on_stack; | |
1930 | ||
1931 | if (!generic_make_request_checks(bio)) | |
1932 | return; | |
1933 | ||
1934 | /* | |
1935 | * We only want one ->make_request_fn to be active at a time, else | |
1936 | * stack usage with stacked devices could be a problem. So use | |
1937 | * current->bio_list to keep a list of requests submited by a | |
1938 | * make_request_fn function. current->bio_list is also used as a | |
1939 | * flag to say if generic_make_request is currently active in this | |
1940 | * task or not. If it is NULL, then no make_request is active. If | |
1941 | * it is non-NULL, then a make_request is active, and new requests | |
1942 | * should be added at the tail | |
1943 | */ | |
1944 | if (current->bio_list) { | |
1945 | bio_list_add(current->bio_list, bio); | |
1946 | return; | |
1947 | } | |
1948 | ||
1949 | /* following loop may be a bit non-obvious, and so deserves some | |
1950 | * explanation. | |
1951 | * Before entering the loop, bio->bi_next is NULL (as all callers | |
1952 | * ensure that) so we have a list with a single bio. | |
1953 | * We pretend that we have just taken it off a longer list, so | |
1954 | * we assign bio_list to a pointer to the bio_list_on_stack, | |
1955 | * thus initialising the bio_list of new bios to be | |
1956 | * added. ->make_request() may indeed add some more bios | |
1957 | * through a recursive call to generic_make_request. If it | |
1958 | * did, we find a non-NULL value in bio_list and re-enter the loop | |
1959 | * from the top. In this case we really did just take the bio | |
1960 | * of the top of the list (no pretending) and so remove it from | |
1961 | * bio_list, and call into ->make_request() again. | |
1962 | */ | |
1963 | BUG_ON(bio->bi_next); | |
1964 | bio_list_init(&bio_list_on_stack); | |
1965 | current->bio_list = &bio_list_on_stack; | |
1966 | do { | |
1967 | struct request_queue *q = bdev_get_queue(bio->bi_bdev); | |
1968 | ||
1969 | q->make_request_fn(q, bio); | |
1970 | ||
1971 | bio = bio_list_pop(current->bio_list); | |
1972 | } while (bio); | |
1973 | current->bio_list = NULL; /* deactivate */ | |
1974 | } | |
1975 | EXPORT_SYMBOL(generic_make_request); | |
1976 | ||
1977 | /** | |
1978 | * submit_bio - submit a bio to the block device layer for I/O | |
1979 | * @rw: whether to %READ or %WRITE, or maybe to %READA (read ahead) | |
1980 | * @bio: The &struct bio which describes the I/O | |
1981 | * | |
1982 | * submit_bio() is very similar in purpose to generic_make_request(), and | |
1983 | * uses that function to do most of the work. Both are fairly rough | |
1984 | * interfaces; @bio must be presetup and ready for I/O. | |
1985 | * | |
1986 | */ | |
1987 | void submit_bio(int rw, struct bio *bio) | |
1988 | { | |
1989 | bio->bi_rw |= rw; | |
1990 | ||
1991 | /* | |
1992 | * If it's a regular read/write or a barrier with data attached, | |
1993 | * go through the normal accounting stuff before submission. | |
1994 | */ | |
1995 | if (bio_has_data(bio)) { | |
1996 | unsigned int count; | |
1997 | ||
1998 | if (unlikely(rw & REQ_WRITE_SAME)) | |
1999 | count = bdev_logical_block_size(bio->bi_bdev) >> 9; | |
2000 | else | |
2001 | count = bio_sectors(bio); | |
2002 | ||
2003 | if (rw & WRITE) { | |
2004 | count_vm_events(PGPGOUT, count); | |
2005 | } else { | |
2006 | task_io_account_read(bio->bi_iter.bi_size); | |
2007 | count_vm_events(PGPGIN, count); | |
2008 | } | |
2009 | ||
2010 | if (unlikely(block_dump)) { | |
2011 | char b[BDEVNAME_SIZE]; | |
2012 | printk(KERN_DEBUG "%s(%d): %s block %Lu on %s (%u sectors)\n", | |
2013 | current->comm, task_pid_nr(current), | |
2014 | (rw & WRITE) ? "WRITE" : "READ", | |
2015 | (unsigned long long)bio->bi_iter.bi_sector, | |
2016 | bdevname(bio->bi_bdev, b), | |
2017 | count); | |
2018 | } | |
2019 | } | |
2020 | ||
2021 | generic_make_request(bio); | |
2022 | } | |
2023 | EXPORT_SYMBOL(submit_bio); | |
2024 | ||
2025 | /** | |
2026 | * blk_rq_check_limits - Helper function to check a request for the queue limit | |
2027 | * @q: the queue | |
2028 | * @rq: the request being checked | |
2029 | * | |
2030 | * Description: | |
2031 | * @rq may have been made based on weaker limitations of upper-level queues | |
2032 | * in request stacking drivers, and it may violate the limitation of @q. | |
2033 | * Since the block layer and the underlying device driver trust @rq | |
2034 | * after it is inserted to @q, it should be checked against @q before | |
2035 | * the insertion using this generic function. | |
2036 | * | |
2037 | * This function should also be useful for request stacking drivers | |
2038 | * in some cases below, so export this function. | |
2039 | * Request stacking drivers like request-based dm may change the queue | |
2040 | * limits while requests are in the queue (e.g. dm's table swapping). | |
2041 | * Such request stacking drivers should check those requests against | |
2042 | * the new queue limits again when they dispatch those requests, | |
2043 | * although such checkings are also done against the old queue limits | |
2044 | * when submitting requests. | |
2045 | */ | |
2046 | int blk_rq_check_limits(struct request_queue *q, struct request *rq) | |
2047 | { | |
2048 | if (!rq_mergeable(rq)) | |
2049 | return 0; | |
2050 | ||
2051 | if (blk_rq_sectors(rq) > blk_queue_get_max_sectors(q, rq->cmd_flags)) { | |
2052 | printk(KERN_ERR "%s: over max size limit.\n", __func__); | |
2053 | return -EIO; | |
2054 | } | |
2055 | ||
2056 | /* | |
2057 | * queue's settings related to segment counting like q->bounce_pfn | |
2058 | * may differ from that of other stacking queues. | |
2059 | * Recalculate it to check the request correctly on this queue's | |
2060 | * limitation. | |
2061 | */ | |
2062 | blk_recalc_rq_segments(rq); | |
2063 | if (rq->nr_phys_segments > queue_max_segments(q)) { | |
2064 | printk(KERN_ERR "%s: over max segments limit.\n", __func__); | |
2065 | return -EIO; | |
2066 | } | |
2067 | ||
2068 | return 0; | |
2069 | } | |
2070 | EXPORT_SYMBOL_GPL(blk_rq_check_limits); | |
2071 | ||
2072 | /** | |
2073 | * blk_insert_cloned_request - Helper for stacking drivers to submit a request | |
2074 | * @q: the queue to submit the request | |
2075 | * @rq: the request being queued | |
2076 | */ | |
2077 | int blk_insert_cloned_request(struct request_queue *q, struct request *rq) | |
2078 | { | |
2079 | unsigned long flags; | |
2080 | int where = ELEVATOR_INSERT_BACK; | |
2081 | ||
2082 | if (blk_rq_check_limits(q, rq)) | |
2083 | return -EIO; | |
2084 | ||
2085 | if (rq->rq_disk && | |
2086 | should_fail_request(&rq->rq_disk->part0, blk_rq_bytes(rq))) | |
2087 | return -EIO; | |
2088 | ||
2089 | if (q->mq_ops) { | |
2090 | if (blk_queue_io_stat(q)) | |
2091 | blk_account_io_start(rq, true); | |
2092 | blk_mq_insert_request(rq, false, true, true); | |
2093 | return 0; | |
2094 | } | |
2095 | ||
2096 | spin_lock_irqsave(q->queue_lock, flags); | |
2097 | if (unlikely(blk_queue_dying(q))) { | |
2098 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2099 | return -ENODEV; | |
2100 | } | |
2101 | ||
2102 | /* | |
2103 | * Submitting request must be dequeued before calling this function | |
2104 | * because it will be linked to another request_queue | |
2105 | */ | |
2106 | BUG_ON(blk_queued_rq(rq)); | |
2107 | ||
2108 | if (rq->cmd_flags & (REQ_FLUSH|REQ_FUA)) | |
2109 | where = ELEVATOR_INSERT_FLUSH; | |
2110 | ||
2111 | add_acct_request(q, rq, where); | |
2112 | if (where == ELEVATOR_INSERT_FLUSH) | |
2113 | __blk_run_queue(q); | |
2114 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2115 | ||
2116 | return 0; | |
2117 | } | |
2118 | EXPORT_SYMBOL_GPL(blk_insert_cloned_request); | |
2119 | ||
2120 | /** | |
2121 | * blk_rq_err_bytes - determine number of bytes till the next failure boundary | |
2122 | * @rq: request to examine | |
2123 | * | |
2124 | * Description: | |
2125 | * A request could be merge of IOs which require different failure | |
2126 | * handling. This function determines the number of bytes which | |
2127 | * can be failed from the beginning of the request without | |
2128 | * crossing into area which need to be retried further. | |
2129 | * | |
2130 | * Return: | |
2131 | * The number of bytes to fail. | |
2132 | * | |
2133 | * Context: | |
2134 | * queue_lock must be held. | |
2135 | */ | |
2136 | unsigned int blk_rq_err_bytes(const struct request *rq) | |
2137 | { | |
2138 | unsigned int ff = rq->cmd_flags & REQ_FAILFAST_MASK; | |
2139 | unsigned int bytes = 0; | |
2140 | struct bio *bio; | |
2141 | ||
2142 | if (!(rq->cmd_flags & REQ_MIXED_MERGE)) | |
2143 | return blk_rq_bytes(rq); | |
2144 | ||
2145 | /* | |
2146 | * Currently the only 'mixing' which can happen is between | |
2147 | * different fastfail types. We can safely fail portions | |
2148 | * which have all the failfast bits that the first one has - | |
2149 | * the ones which are at least as eager to fail as the first | |
2150 | * one. | |
2151 | */ | |
2152 | for (bio = rq->bio; bio; bio = bio->bi_next) { | |
2153 | if ((bio->bi_rw & ff) != ff) | |
2154 | break; | |
2155 | bytes += bio->bi_iter.bi_size; | |
2156 | } | |
2157 | ||
2158 | /* this could lead to infinite loop */ | |
2159 | BUG_ON(blk_rq_bytes(rq) && !bytes); | |
2160 | return bytes; | |
2161 | } | |
2162 | EXPORT_SYMBOL_GPL(blk_rq_err_bytes); | |
2163 | ||
2164 | void blk_account_io_completion(struct request *req, unsigned int bytes) | |
2165 | { | |
2166 | if (blk_do_io_stat(req)) { | |
2167 | const int rw = rq_data_dir(req); | |
2168 | struct hd_struct *part; | |
2169 | int cpu; | |
2170 | ||
2171 | cpu = part_stat_lock(); | |
2172 | part = req->part; | |
2173 | part_stat_add(cpu, part, sectors[rw], bytes >> 9); | |
2174 | part_stat_unlock(); | |
2175 | } | |
2176 | } | |
2177 | ||
2178 | void blk_account_io_done(struct request *req) | |
2179 | { | |
2180 | /* | |
2181 | * Account IO completion. flush_rq isn't accounted as a | |
2182 | * normal IO on queueing nor completion. Accounting the | |
2183 | * containing request is enough. | |
2184 | */ | |
2185 | if (blk_do_io_stat(req) && !(req->cmd_flags & REQ_FLUSH_SEQ)) { | |
2186 | unsigned long duration = jiffies - req->start_time; | |
2187 | const int rw = rq_data_dir(req); | |
2188 | struct hd_struct *part; | |
2189 | int cpu; | |
2190 | ||
2191 | cpu = part_stat_lock(); | |
2192 | part = req->part; | |
2193 | ||
2194 | part_stat_inc(cpu, part, ios[rw]); | |
2195 | part_stat_add(cpu, part, ticks[rw], duration); | |
2196 | part_round_stats(cpu, part); | |
2197 | part_dec_in_flight(part, rw); | |
2198 | ||
2199 | hd_struct_put(part); | |
2200 | part_stat_unlock(); | |
2201 | } | |
2202 | } | |
2203 | ||
2204 | #ifdef CONFIG_PM | |
2205 | /* | |
2206 | * Don't process normal requests when queue is suspended | |
2207 | * or in the process of suspending/resuming | |
2208 | */ | |
2209 | static struct request *blk_pm_peek_request(struct request_queue *q, | |
2210 | struct request *rq) | |
2211 | { | |
2212 | if (q->dev && (q->rpm_status == RPM_SUSPENDED || | |
2213 | (q->rpm_status != RPM_ACTIVE && !(rq->cmd_flags & REQ_PM)))) | |
2214 | return NULL; | |
2215 | else | |
2216 | return rq; | |
2217 | } | |
2218 | #else | |
2219 | static inline struct request *blk_pm_peek_request(struct request_queue *q, | |
2220 | struct request *rq) | |
2221 | { | |
2222 | return rq; | |
2223 | } | |
2224 | #endif | |
2225 | ||
2226 | void blk_account_io_start(struct request *rq, bool new_io) | |
2227 | { | |
2228 | struct hd_struct *part; | |
2229 | int rw = rq_data_dir(rq); | |
2230 | int cpu; | |
2231 | ||
2232 | if (!blk_do_io_stat(rq)) | |
2233 | return; | |
2234 | ||
2235 | cpu = part_stat_lock(); | |
2236 | ||
2237 | if (!new_io) { | |
2238 | part = rq->part; | |
2239 | part_stat_inc(cpu, part, merges[rw]); | |
2240 | } else { | |
2241 | part = disk_map_sector_rcu(rq->rq_disk, blk_rq_pos(rq)); | |
2242 | if (!hd_struct_try_get(part)) { | |
2243 | /* | |
2244 | * The partition is already being removed, | |
2245 | * the request will be accounted on the disk only | |
2246 | * | |
2247 | * We take a reference on disk->part0 although that | |
2248 | * partition will never be deleted, so we can treat | |
2249 | * it as any other partition. | |
2250 | */ | |
2251 | part = &rq->rq_disk->part0; | |
2252 | hd_struct_get(part); | |
2253 | } | |
2254 | part_round_stats(cpu, part); | |
2255 | part_inc_in_flight(part, rw); | |
2256 | rq->part = part; | |
2257 | } | |
2258 | ||
2259 | part_stat_unlock(); | |
2260 | } | |
2261 | ||
2262 | /** | |
2263 | * blk_peek_request - peek at the top of a request queue | |
2264 | * @q: request queue to peek at | |
2265 | * | |
2266 | * Description: | |
2267 | * Return the request at the top of @q. The returned request | |
2268 | * should be started using blk_start_request() before LLD starts | |
2269 | * processing it. | |
2270 | * | |
2271 | * Return: | |
2272 | * Pointer to the request at the top of @q if available. Null | |
2273 | * otherwise. | |
2274 | * | |
2275 | * Context: | |
2276 | * queue_lock must be held. | |
2277 | */ | |
2278 | struct request *blk_peek_request(struct request_queue *q) | |
2279 | { | |
2280 | struct request *rq; | |
2281 | int ret; | |
2282 | ||
2283 | while ((rq = __elv_next_request(q)) != NULL) { | |
2284 | ||
2285 | rq = blk_pm_peek_request(q, rq); | |
2286 | if (!rq) | |
2287 | break; | |
2288 | ||
2289 | if (!(rq->cmd_flags & REQ_STARTED)) { | |
2290 | /* | |
2291 | * This is the first time the device driver | |
2292 | * sees this request (possibly after | |
2293 | * requeueing). Notify IO scheduler. | |
2294 | */ | |
2295 | if (rq->cmd_flags & REQ_SORTED) | |
2296 | elv_activate_rq(q, rq); | |
2297 | ||
2298 | /* | |
2299 | * just mark as started even if we don't start | |
2300 | * it, a request that has been delayed should | |
2301 | * not be passed by new incoming requests | |
2302 | */ | |
2303 | rq->cmd_flags |= REQ_STARTED; | |
2304 | trace_block_rq_issue(q, rq); | |
2305 | } | |
2306 | ||
2307 | if (!q->boundary_rq || q->boundary_rq == rq) { | |
2308 | q->end_sector = rq_end_sector(rq); | |
2309 | q->boundary_rq = NULL; | |
2310 | } | |
2311 | ||
2312 | if (rq->cmd_flags & REQ_DONTPREP) | |
2313 | break; | |
2314 | ||
2315 | if (q->dma_drain_size && blk_rq_bytes(rq)) { | |
2316 | /* | |
2317 | * make sure space for the drain appears we | |
2318 | * know we can do this because max_hw_segments | |
2319 | * has been adjusted to be one fewer than the | |
2320 | * device can handle | |
2321 | */ | |
2322 | rq->nr_phys_segments++; | |
2323 | } | |
2324 | ||
2325 | if (!q->prep_rq_fn) | |
2326 | break; | |
2327 | ||
2328 | ret = q->prep_rq_fn(q, rq); | |
2329 | if (ret == BLKPREP_OK) { | |
2330 | break; | |
2331 | } else if (ret == BLKPREP_DEFER) { | |
2332 | /* | |
2333 | * the request may have been (partially) prepped. | |
2334 | * we need to keep this request in the front to | |
2335 | * avoid resource deadlock. REQ_STARTED will | |
2336 | * prevent other fs requests from passing this one. | |
2337 | */ | |
2338 | if (q->dma_drain_size && blk_rq_bytes(rq) && | |
2339 | !(rq->cmd_flags & REQ_DONTPREP)) { | |
2340 | /* | |
2341 | * remove the space for the drain we added | |
2342 | * so that we don't add it again | |
2343 | */ | |
2344 | --rq->nr_phys_segments; | |
2345 | } | |
2346 | ||
2347 | rq = NULL; | |
2348 | break; | |
2349 | } else if (ret == BLKPREP_KILL) { | |
2350 | rq->cmd_flags |= REQ_QUIET; | |
2351 | /* | |
2352 | * Mark this request as started so we don't trigger | |
2353 | * any debug logic in the end I/O path. | |
2354 | */ | |
2355 | blk_start_request(rq); | |
2356 | __blk_end_request_all(rq, -EIO); | |
2357 | } else { | |
2358 | printk(KERN_ERR "%s: bad return=%d\n", __func__, ret); | |
2359 | break; | |
2360 | } | |
2361 | } | |
2362 | ||
2363 | return rq; | |
2364 | } | |
2365 | EXPORT_SYMBOL(blk_peek_request); | |
2366 | ||
2367 | void blk_dequeue_request(struct request *rq) | |
2368 | { | |
2369 | struct request_queue *q = rq->q; | |
2370 | ||
2371 | BUG_ON(list_empty(&rq->queuelist)); | |
2372 | BUG_ON(ELV_ON_HASH(rq)); | |
2373 | ||
2374 | list_del_init(&rq->queuelist); | |
2375 | ||
2376 | /* | |
2377 | * the time frame between a request being removed from the lists | |
2378 | * and to it is freed is accounted as io that is in progress at | |
2379 | * the driver side. | |
2380 | */ | |
2381 | if (blk_account_rq(rq)) { | |
2382 | q->in_flight[rq_is_sync(rq)]++; | |
2383 | set_io_start_time_ns(rq); | |
2384 | } | |
2385 | } | |
2386 | ||
2387 | /** | |
2388 | * blk_start_request - start request processing on the driver | |
2389 | * @req: request to dequeue | |
2390 | * | |
2391 | * Description: | |
2392 | * Dequeue @req and start timeout timer on it. This hands off the | |
2393 | * request to the driver. | |
2394 | * | |
2395 | * Block internal functions which don't want to start timer should | |
2396 | * call blk_dequeue_request(). | |
2397 | * | |
2398 | * Context: | |
2399 | * queue_lock must be held. | |
2400 | */ | |
2401 | void blk_start_request(struct request *req) | |
2402 | { | |
2403 | blk_dequeue_request(req); | |
2404 | ||
2405 | /* | |
2406 | * We are now handing the request to the hardware, initialize | |
2407 | * resid_len to full count and add the timeout handler. | |
2408 | */ | |
2409 | req->resid_len = blk_rq_bytes(req); | |
2410 | if (unlikely(blk_bidi_rq(req))) | |
2411 | req->next_rq->resid_len = blk_rq_bytes(req->next_rq); | |
2412 | ||
2413 | BUG_ON(test_bit(REQ_ATOM_COMPLETE, &req->atomic_flags)); | |
2414 | blk_add_timer(req); | |
2415 | } | |
2416 | EXPORT_SYMBOL(blk_start_request); | |
2417 | ||
2418 | /** | |
2419 | * blk_fetch_request - fetch a request from a request queue | |
2420 | * @q: request queue to fetch a request from | |
2421 | * | |
2422 | * Description: | |
2423 | * Return the request at the top of @q. The request is started on | |
2424 | * return and LLD can start processing it immediately. | |
2425 | * | |
2426 | * Return: | |
2427 | * Pointer to the request at the top of @q if available. Null | |
2428 | * otherwise. | |
2429 | * | |
2430 | * Context: | |
2431 | * queue_lock must be held. | |
2432 | */ | |
2433 | struct request *blk_fetch_request(struct request_queue *q) | |
2434 | { | |
2435 | struct request *rq; | |
2436 | ||
2437 | rq = blk_peek_request(q); | |
2438 | if (rq) | |
2439 | blk_start_request(rq); | |
2440 | return rq; | |
2441 | } | |
2442 | EXPORT_SYMBOL(blk_fetch_request); | |
2443 | ||
2444 | /** | |
2445 | * blk_update_request - Special helper function for request stacking drivers | |
2446 | * @req: the request being processed | |
2447 | * @error: %0 for success, < %0 for error | |
2448 | * @nr_bytes: number of bytes to complete @req | |
2449 | * | |
2450 | * Description: | |
2451 | * Ends I/O on a number of bytes attached to @req, but doesn't complete | |
2452 | * the request structure even if @req doesn't have leftover. | |
2453 | * If @req has leftover, sets it up for the next range of segments. | |
2454 | * | |
2455 | * This special helper function is only for request stacking drivers | |
2456 | * (e.g. request-based dm) so that they can handle partial completion. | |
2457 | * Actual device drivers should use blk_end_request instead. | |
2458 | * | |
2459 | * Passing the result of blk_rq_bytes() as @nr_bytes guarantees | |
2460 | * %false return from this function. | |
2461 | * | |
2462 | * Return: | |
2463 | * %false - this request doesn't have any more data | |
2464 | * %true - this request has more data | |
2465 | **/ | |
2466 | bool blk_update_request(struct request *req, int error, unsigned int nr_bytes) | |
2467 | { | |
2468 | int total_bytes; | |
2469 | ||
2470 | trace_block_rq_complete(req->q, req, nr_bytes); | |
2471 | ||
2472 | if (!req->bio) | |
2473 | return false; | |
2474 | ||
2475 | /* | |
2476 | * For fs requests, rq is just carrier of independent bio's | |
2477 | * and each partial completion should be handled separately. | |
2478 | * Reset per-request error on each partial completion. | |
2479 | * | |
2480 | * TODO: tj: This is too subtle. It would be better to let | |
2481 | * low level drivers do what they see fit. | |
2482 | */ | |
2483 | if (req->cmd_type == REQ_TYPE_FS) | |
2484 | req->errors = 0; | |
2485 | ||
2486 | if (error && req->cmd_type == REQ_TYPE_FS && | |
2487 | !(req->cmd_flags & REQ_QUIET)) { | |
2488 | char *error_type; | |
2489 | ||
2490 | switch (error) { | |
2491 | case -ENOLINK: | |
2492 | error_type = "recoverable transport"; | |
2493 | break; | |
2494 | case -EREMOTEIO: | |
2495 | error_type = "critical target"; | |
2496 | break; | |
2497 | case -EBADE: | |
2498 | error_type = "critical nexus"; | |
2499 | break; | |
2500 | case -ETIMEDOUT: | |
2501 | error_type = "timeout"; | |
2502 | break; | |
2503 | case -ENOSPC: | |
2504 | error_type = "critical space allocation"; | |
2505 | break; | |
2506 | case -ENODATA: | |
2507 | error_type = "critical medium"; | |
2508 | break; | |
2509 | case -EIO: | |
2510 | default: | |
2511 | error_type = "I/O"; | |
2512 | break; | |
2513 | } | |
2514 | printk_ratelimited(KERN_ERR "%s: %s error, dev %s, sector %llu\n", | |
2515 | __func__, error_type, req->rq_disk ? | |
2516 | req->rq_disk->disk_name : "?", | |
2517 | (unsigned long long)blk_rq_pos(req)); | |
2518 | ||
2519 | } | |
2520 | ||
2521 | blk_account_io_completion(req, nr_bytes); | |
2522 | ||
2523 | total_bytes = 0; | |
2524 | while (req->bio) { | |
2525 | struct bio *bio = req->bio; | |
2526 | unsigned bio_bytes = min(bio->bi_iter.bi_size, nr_bytes); | |
2527 | ||
2528 | if (bio_bytes == bio->bi_iter.bi_size) | |
2529 | req->bio = bio->bi_next; | |
2530 | ||
2531 | req_bio_endio(req, bio, bio_bytes, error); | |
2532 | ||
2533 | total_bytes += bio_bytes; | |
2534 | nr_bytes -= bio_bytes; | |
2535 | ||
2536 | if (!nr_bytes) | |
2537 | break; | |
2538 | } | |
2539 | ||
2540 | /* | |
2541 | * completely done | |
2542 | */ | |
2543 | if (!req->bio) { | |
2544 | /* | |
2545 | * Reset counters so that the request stacking driver | |
2546 | * can find how many bytes remain in the request | |
2547 | * later. | |
2548 | */ | |
2549 | req->__data_len = 0; | |
2550 | return false; | |
2551 | } | |
2552 | ||
2553 | req->__data_len -= total_bytes; | |
2554 | ||
2555 | /* update sector only for requests with clear definition of sector */ | |
2556 | if (req->cmd_type == REQ_TYPE_FS) | |
2557 | req->__sector += total_bytes >> 9; | |
2558 | ||
2559 | /* mixed attributes always follow the first bio */ | |
2560 | if (req->cmd_flags & REQ_MIXED_MERGE) { | |
2561 | req->cmd_flags &= ~REQ_FAILFAST_MASK; | |
2562 | req->cmd_flags |= req->bio->bi_rw & REQ_FAILFAST_MASK; | |
2563 | } | |
2564 | ||
2565 | /* | |
2566 | * If total number of sectors is less than the first segment | |
2567 | * size, something has gone terribly wrong. | |
2568 | */ | |
2569 | if (blk_rq_bytes(req) < blk_rq_cur_bytes(req)) { | |
2570 | blk_dump_rq_flags(req, "request botched"); | |
2571 | req->__data_len = blk_rq_cur_bytes(req); | |
2572 | } | |
2573 | ||
2574 | /* recalculate the number of segments */ | |
2575 | blk_recalc_rq_segments(req); | |
2576 | ||
2577 | return true; | |
2578 | } | |
2579 | EXPORT_SYMBOL_GPL(blk_update_request); | |
2580 | ||
2581 | static bool blk_update_bidi_request(struct request *rq, int error, | |
2582 | unsigned int nr_bytes, | |
2583 | unsigned int bidi_bytes) | |
2584 | { | |
2585 | if (blk_update_request(rq, error, nr_bytes)) | |
2586 | return true; | |
2587 | ||
2588 | /* Bidi request must be completed as a whole */ | |
2589 | if (unlikely(blk_bidi_rq(rq)) && | |
2590 | blk_update_request(rq->next_rq, error, bidi_bytes)) | |
2591 | return true; | |
2592 | ||
2593 | if (blk_queue_add_random(rq->q)) | |
2594 | add_disk_randomness(rq->rq_disk); | |
2595 | ||
2596 | return false; | |
2597 | } | |
2598 | ||
2599 | /** | |
2600 | * blk_unprep_request - unprepare a request | |
2601 | * @req: the request | |
2602 | * | |
2603 | * This function makes a request ready for complete resubmission (or | |
2604 | * completion). It happens only after all error handling is complete, | |
2605 | * so represents the appropriate moment to deallocate any resources | |
2606 | * that were allocated to the request in the prep_rq_fn. The queue | |
2607 | * lock is held when calling this. | |
2608 | */ | |
2609 | void blk_unprep_request(struct request *req) | |
2610 | { | |
2611 | struct request_queue *q = req->q; | |
2612 | ||
2613 | req->cmd_flags &= ~REQ_DONTPREP; | |
2614 | if (q->unprep_rq_fn) | |
2615 | q->unprep_rq_fn(q, req); | |
2616 | } | |
2617 | EXPORT_SYMBOL_GPL(blk_unprep_request); | |
2618 | ||
2619 | /* | |
2620 | * queue lock must be held | |
2621 | */ | |
2622 | void blk_finish_request(struct request *req, int error) | |
2623 | { | |
2624 | if (req->cmd_flags & REQ_QUEUED) | |
2625 | blk_queue_end_tag(req->q, req); | |
2626 | ||
2627 | BUG_ON(blk_queued_rq(req)); | |
2628 | ||
2629 | if (unlikely(laptop_mode) && req->cmd_type == REQ_TYPE_FS) | |
2630 | laptop_io_completion(&req->q->backing_dev_info); | |
2631 | ||
2632 | blk_delete_timer(req); | |
2633 | ||
2634 | if (req->cmd_flags & REQ_DONTPREP) | |
2635 | blk_unprep_request(req); | |
2636 | ||
2637 | blk_account_io_done(req); | |
2638 | ||
2639 | if (req->end_io) | |
2640 | req->end_io(req, error); | |
2641 | else { | |
2642 | if (blk_bidi_rq(req)) | |
2643 | __blk_put_request(req->next_rq->q, req->next_rq); | |
2644 | ||
2645 | __blk_put_request(req->q, req); | |
2646 | } | |
2647 | } | |
2648 | EXPORT_SYMBOL(blk_finish_request); | |
2649 | ||
2650 | /** | |
2651 | * blk_end_bidi_request - Complete a bidi request | |
2652 | * @rq: the request to complete | |
2653 | * @error: %0 for success, < %0 for error | |
2654 | * @nr_bytes: number of bytes to complete @rq | |
2655 | * @bidi_bytes: number of bytes to complete @rq->next_rq | |
2656 | * | |
2657 | * Description: | |
2658 | * Ends I/O on a number of bytes attached to @rq and @rq->next_rq. | |
2659 | * Drivers that supports bidi can safely call this member for any | |
2660 | * type of request, bidi or uni. In the later case @bidi_bytes is | |
2661 | * just ignored. | |
2662 | * | |
2663 | * Return: | |
2664 | * %false - we are done with this request | |
2665 | * %true - still buffers pending for this request | |
2666 | **/ | |
2667 | static bool blk_end_bidi_request(struct request *rq, int error, | |
2668 | unsigned int nr_bytes, unsigned int bidi_bytes) | |
2669 | { | |
2670 | struct request_queue *q = rq->q; | |
2671 | unsigned long flags; | |
2672 | ||
2673 | if (blk_update_bidi_request(rq, error, nr_bytes, bidi_bytes)) | |
2674 | return true; | |
2675 | ||
2676 | spin_lock_irqsave(q->queue_lock, flags); | |
2677 | blk_finish_request(rq, error); | |
2678 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2679 | ||
2680 | return false; | |
2681 | } | |
2682 | ||
2683 | /** | |
2684 | * __blk_end_bidi_request - Complete a bidi request with queue lock held | |
2685 | * @rq: the request to complete | |
2686 | * @error: %0 for success, < %0 for error | |
2687 | * @nr_bytes: number of bytes to complete @rq | |
2688 | * @bidi_bytes: number of bytes to complete @rq->next_rq | |
2689 | * | |
2690 | * Description: | |
2691 | * Identical to blk_end_bidi_request() except that queue lock is | |
2692 | * assumed to be locked on entry and remains so on return. | |
2693 | * | |
2694 | * Return: | |
2695 | * %false - we are done with this request | |
2696 | * %true - still buffers pending for this request | |
2697 | **/ | |
2698 | bool __blk_end_bidi_request(struct request *rq, int error, | |
2699 | unsigned int nr_bytes, unsigned int bidi_bytes) | |
2700 | { | |
2701 | if (blk_update_bidi_request(rq, error, nr_bytes, bidi_bytes)) | |
2702 | return true; | |
2703 | ||
2704 | blk_finish_request(rq, error); | |
2705 | ||
2706 | return false; | |
2707 | } | |
2708 | ||
2709 | /** | |
2710 | * blk_end_request - Helper function for drivers to complete the request. | |
2711 | * @rq: the request being processed | |
2712 | * @error: %0 for success, < %0 for error | |
2713 | * @nr_bytes: number of bytes to complete | |
2714 | * | |
2715 | * Description: | |
2716 | * Ends I/O on a number of bytes attached to @rq. | |
2717 | * If @rq has leftover, sets it up for the next range of segments. | |
2718 | * | |
2719 | * Return: | |
2720 | * %false - we are done with this request | |
2721 | * %true - still buffers pending for this request | |
2722 | **/ | |
2723 | bool blk_end_request(struct request *rq, int error, unsigned int nr_bytes) | |
2724 | { | |
2725 | return blk_end_bidi_request(rq, error, nr_bytes, 0); | |
2726 | } | |
2727 | EXPORT_SYMBOL(blk_end_request); | |
2728 | ||
2729 | /** | |
2730 | * blk_end_request_all - Helper function for drives to finish the request. | |
2731 | * @rq: the request to finish | |
2732 | * @error: %0 for success, < %0 for error | |
2733 | * | |
2734 | * Description: | |
2735 | * Completely finish @rq. | |
2736 | */ | |
2737 | void blk_end_request_all(struct request *rq, int error) | |
2738 | { | |
2739 | bool pending; | |
2740 | unsigned int bidi_bytes = 0; | |
2741 | ||
2742 | if (unlikely(blk_bidi_rq(rq))) | |
2743 | bidi_bytes = blk_rq_bytes(rq->next_rq); | |
2744 | ||
2745 | pending = blk_end_bidi_request(rq, error, blk_rq_bytes(rq), bidi_bytes); | |
2746 | BUG_ON(pending); | |
2747 | } | |
2748 | EXPORT_SYMBOL(blk_end_request_all); | |
2749 | ||
2750 | /** | |
2751 | * blk_end_request_cur - Helper function to finish the current request chunk. | |
2752 | * @rq: the request to finish the current chunk for | |
2753 | * @error: %0 for success, < %0 for error | |
2754 | * | |
2755 | * Description: | |
2756 | * Complete the current consecutively mapped chunk from @rq. | |
2757 | * | |
2758 | * Return: | |
2759 | * %false - we are done with this request | |
2760 | * %true - still buffers pending for this request | |
2761 | */ | |
2762 | bool blk_end_request_cur(struct request *rq, int error) | |
2763 | { | |
2764 | return blk_end_request(rq, error, blk_rq_cur_bytes(rq)); | |
2765 | } | |
2766 | EXPORT_SYMBOL(blk_end_request_cur); | |
2767 | ||
2768 | /** | |
2769 | * blk_end_request_err - Finish a request till the next failure boundary. | |
2770 | * @rq: the request to finish till the next failure boundary for | |
2771 | * @error: must be negative errno | |
2772 | * | |
2773 | * Description: | |
2774 | * Complete @rq till the next failure boundary. | |
2775 | * | |
2776 | * Return: | |
2777 | * %false - we are done with this request | |
2778 | * %true - still buffers pending for this request | |
2779 | */ | |
2780 | bool blk_end_request_err(struct request *rq, int error) | |
2781 | { | |
2782 | WARN_ON(error >= 0); | |
2783 | return blk_end_request(rq, error, blk_rq_err_bytes(rq)); | |
2784 | } | |
2785 | EXPORT_SYMBOL_GPL(blk_end_request_err); | |
2786 | ||
2787 | /** | |
2788 | * __blk_end_request - Helper function for drivers to complete the request. | |
2789 | * @rq: the request being processed | |
2790 | * @error: %0 for success, < %0 for error | |
2791 | * @nr_bytes: number of bytes to complete | |
2792 | * | |
2793 | * Description: | |
2794 | * Must be called with queue lock held unlike blk_end_request(). | |
2795 | * | |
2796 | * Return: | |
2797 | * %false - we are done with this request | |
2798 | * %true - still buffers pending for this request | |
2799 | **/ | |
2800 | bool __blk_end_request(struct request *rq, int error, unsigned int nr_bytes) | |
2801 | { | |
2802 | return __blk_end_bidi_request(rq, error, nr_bytes, 0); | |
2803 | } | |
2804 | EXPORT_SYMBOL(__blk_end_request); | |
2805 | ||
2806 | /** | |
2807 | * __blk_end_request_all - Helper function for drives to finish the request. | |
2808 | * @rq: the request to finish | |
2809 | * @error: %0 for success, < %0 for error | |
2810 | * | |
2811 | * Description: | |
2812 | * Completely finish @rq. Must be called with queue lock held. | |
2813 | */ | |
2814 | void __blk_end_request_all(struct request *rq, int error) | |
2815 | { | |
2816 | bool pending; | |
2817 | unsigned int bidi_bytes = 0; | |
2818 | ||
2819 | if (unlikely(blk_bidi_rq(rq))) | |
2820 | bidi_bytes = blk_rq_bytes(rq->next_rq); | |
2821 | ||
2822 | pending = __blk_end_bidi_request(rq, error, blk_rq_bytes(rq), bidi_bytes); | |
2823 | BUG_ON(pending); | |
2824 | } | |
2825 | EXPORT_SYMBOL(__blk_end_request_all); | |
2826 | ||
2827 | /** | |
2828 | * __blk_end_request_cur - Helper function to finish the current request chunk. | |
2829 | * @rq: the request to finish the current chunk for | |
2830 | * @error: %0 for success, < %0 for error | |
2831 | * | |
2832 | * Description: | |
2833 | * Complete the current consecutively mapped chunk from @rq. Must | |
2834 | * be called with queue lock held. | |
2835 | * | |
2836 | * Return: | |
2837 | * %false - we are done with this request | |
2838 | * %true - still buffers pending for this request | |
2839 | */ | |
2840 | bool __blk_end_request_cur(struct request *rq, int error) | |
2841 | { | |
2842 | return __blk_end_request(rq, error, blk_rq_cur_bytes(rq)); | |
2843 | } | |
2844 | EXPORT_SYMBOL(__blk_end_request_cur); | |
2845 | ||
2846 | /** | |
2847 | * __blk_end_request_err - Finish a request till the next failure boundary. | |
2848 | * @rq: the request to finish till the next failure boundary for | |
2849 | * @error: must be negative errno | |
2850 | * | |
2851 | * Description: | |
2852 | * Complete @rq till the next failure boundary. Must be called | |
2853 | * with queue lock held. | |
2854 | * | |
2855 | * Return: | |
2856 | * %false - we are done with this request | |
2857 | * %true - still buffers pending for this request | |
2858 | */ | |
2859 | bool __blk_end_request_err(struct request *rq, int error) | |
2860 | { | |
2861 | WARN_ON(error >= 0); | |
2862 | return __blk_end_request(rq, error, blk_rq_err_bytes(rq)); | |
2863 | } | |
2864 | EXPORT_SYMBOL_GPL(__blk_end_request_err); | |
2865 | ||
2866 | void blk_rq_bio_prep(struct request_queue *q, struct request *rq, | |
2867 | struct bio *bio) | |
2868 | { | |
2869 | /* Bit 0 (R/W) is identical in rq->cmd_flags and bio->bi_rw */ | |
2870 | rq->cmd_flags |= bio->bi_rw & REQ_WRITE; | |
2871 | ||
2872 | if (bio_has_data(bio)) | |
2873 | rq->nr_phys_segments = bio_phys_segments(q, bio); | |
2874 | ||
2875 | rq->__data_len = bio->bi_iter.bi_size; | |
2876 | rq->bio = rq->biotail = bio; | |
2877 | ||
2878 | if (bio->bi_bdev) | |
2879 | rq->rq_disk = bio->bi_bdev->bd_disk; | |
2880 | } | |
2881 | ||
2882 | #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE | |
2883 | /** | |
2884 | * rq_flush_dcache_pages - Helper function to flush all pages in a request | |
2885 | * @rq: the request to be flushed | |
2886 | * | |
2887 | * Description: | |
2888 | * Flush all pages in @rq. | |
2889 | */ | |
2890 | void rq_flush_dcache_pages(struct request *rq) | |
2891 | { | |
2892 | struct req_iterator iter; | |
2893 | struct bio_vec bvec; | |
2894 | ||
2895 | rq_for_each_segment(bvec, rq, iter) | |
2896 | flush_dcache_page(bvec.bv_page); | |
2897 | } | |
2898 | EXPORT_SYMBOL_GPL(rq_flush_dcache_pages); | |
2899 | #endif | |
2900 | ||
2901 | /** | |
2902 | * blk_lld_busy - Check if underlying low-level drivers of a device are busy | |
2903 | * @q : the queue of the device being checked | |
2904 | * | |
2905 | * Description: | |
2906 | * Check if underlying low-level drivers of a device are busy. | |
2907 | * If the drivers want to export their busy state, they must set own | |
2908 | * exporting function using blk_queue_lld_busy() first. | |
2909 | * | |
2910 | * Basically, this function is used only by request stacking drivers | |
2911 | * to stop dispatching requests to underlying devices when underlying | |
2912 | * devices are busy. This behavior helps more I/O merging on the queue | |
2913 | * of the request stacking driver and prevents I/O throughput regression | |
2914 | * on burst I/O load. | |
2915 | * | |
2916 | * Return: | |
2917 | * 0 - Not busy (The request stacking driver should dispatch request) | |
2918 | * 1 - Busy (The request stacking driver should stop dispatching request) | |
2919 | */ | |
2920 | int blk_lld_busy(struct request_queue *q) | |
2921 | { | |
2922 | if (q->lld_busy_fn) | |
2923 | return q->lld_busy_fn(q); | |
2924 | ||
2925 | return 0; | |
2926 | } | |
2927 | EXPORT_SYMBOL_GPL(blk_lld_busy); | |
2928 | ||
2929 | /** | |
2930 | * blk_rq_unprep_clone - Helper function to free all bios in a cloned request | |
2931 | * @rq: the clone request to be cleaned up | |
2932 | * | |
2933 | * Description: | |
2934 | * Free all bios in @rq for a cloned request. | |
2935 | */ | |
2936 | void blk_rq_unprep_clone(struct request *rq) | |
2937 | { | |
2938 | struct bio *bio; | |
2939 | ||
2940 | while ((bio = rq->bio) != NULL) { | |
2941 | rq->bio = bio->bi_next; | |
2942 | ||
2943 | bio_put(bio); | |
2944 | } | |
2945 | } | |
2946 | EXPORT_SYMBOL_GPL(blk_rq_unprep_clone); | |
2947 | ||
2948 | /* | |
2949 | * Copy attributes of the original request to the clone request. | |
2950 | * The actual data parts (e.g. ->cmd, ->sense) are not copied. | |
2951 | */ | |
2952 | static void __blk_rq_prep_clone(struct request *dst, struct request *src) | |
2953 | { | |
2954 | dst->cpu = src->cpu; | |
2955 | dst->cmd_flags |= (src->cmd_flags & REQ_CLONE_MASK) | REQ_NOMERGE; | |
2956 | dst->cmd_type = src->cmd_type; | |
2957 | dst->__sector = blk_rq_pos(src); | |
2958 | dst->__data_len = blk_rq_bytes(src); | |
2959 | dst->nr_phys_segments = src->nr_phys_segments; | |
2960 | dst->ioprio = src->ioprio; | |
2961 | dst->extra_len = src->extra_len; | |
2962 | } | |
2963 | ||
2964 | /** | |
2965 | * blk_rq_prep_clone - Helper function to setup clone request | |
2966 | * @rq: the request to be setup | |
2967 | * @rq_src: original request to be cloned | |
2968 | * @bs: bio_set that bios for clone are allocated from | |
2969 | * @gfp_mask: memory allocation mask for bio | |
2970 | * @bio_ctr: setup function to be called for each clone bio. | |
2971 | * Returns %0 for success, non %0 for failure. | |
2972 | * @data: private data to be passed to @bio_ctr | |
2973 | * | |
2974 | * Description: | |
2975 | * Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq. | |
2976 | * The actual data parts of @rq_src (e.g. ->cmd, ->sense) | |
2977 | * are not copied, and copying such parts is the caller's responsibility. | |
2978 | * Also, pages which the original bios are pointing to are not copied | |
2979 | * and the cloned bios just point same pages. | |
2980 | * So cloned bios must be completed before original bios, which means | |
2981 | * the caller must complete @rq before @rq_src. | |
2982 | */ | |
2983 | int blk_rq_prep_clone(struct request *rq, struct request *rq_src, | |
2984 | struct bio_set *bs, gfp_t gfp_mask, | |
2985 | int (*bio_ctr)(struct bio *, struct bio *, void *), | |
2986 | void *data) | |
2987 | { | |
2988 | struct bio *bio, *bio_src; | |
2989 | ||
2990 | if (!bs) | |
2991 | bs = fs_bio_set; | |
2992 | ||
2993 | __rq_for_each_bio(bio_src, rq_src) { | |
2994 | bio = bio_clone_fast(bio_src, gfp_mask, bs); | |
2995 | if (!bio) | |
2996 | goto free_and_out; | |
2997 | ||
2998 | if (bio_ctr && bio_ctr(bio, bio_src, data)) | |
2999 | goto free_and_out; | |
3000 | ||
3001 | if (rq->bio) { | |
3002 | rq->biotail->bi_next = bio; | |
3003 | rq->biotail = bio; | |
3004 | } else | |
3005 | rq->bio = rq->biotail = bio; | |
3006 | } | |
3007 | ||
3008 | __blk_rq_prep_clone(rq, rq_src); | |
3009 | ||
3010 | return 0; | |
3011 | ||
3012 | free_and_out: | |
3013 | if (bio) | |
3014 | bio_put(bio); | |
3015 | blk_rq_unprep_clone(rq); | |
3016 | ||
3017 | return -ENOMEM; | |
3018 | } | |
3019 | EXPORT_SYMBOL_GPL(blk_rq_prep_clone); | |
3020 | ||
3021 | int kblockd_schedule_work(struct work_struct *work) | |
3022 | { | |
3023 | return queue_work(kblockd_workqueue, work); | |
3024 | } | |
3025 | EXPORT_SYMBOL(kblockd_schedule_work); | |
3026 | ||
3027 | int kblockd_schedule_delayed_work(struct delayed_work *dwork, | |
3028 | unsigned long delay) | |
3029 | { | |
3030 | return queue_delayed_work(kblockd_workqueue, dwork, delay); | |
3031 | } | |
3032 | EXPORT_SYMBOL(kblockd_schedule_delayed_work); | |
3033 | ||
3034 | int kblockd_schedule_delayed_work_on(int cpu, struct delayed_work *dwork, | |
3035 | unsigned long delay) | |
3036 | { | |
3037 | return queue_delayed_work_on(cpu, kblockd_workqueue, dwork, delay); | |
3038 | } | |
3039 | EXPORT_SYMBOL(kblockd_schedule_delayed_work_on); | |
3040 | ||
3041 | /** | |
3042 | * blk_start_plug - initialize blk_plug and track it inside the task_struct | |
3043 | * @plug: The &struct blk_plug that needs to be initialized | |
3044 | * | |
3045 | * Description: | |
3046 | * Tracking blk_plug inside the task_struct will help with auto-flushing the | |
3047 | * pending I/O should the task end up blocking between blk_start_plug() and | |
3048 | * blk_finish_plug(). This is important from a performance perspective, but | |
3049 | * also ensures that we don't deadlock. For instance, if the task is blocking | |
3050 | * for a memory allocation, memory reclaim could end up wanting to free a | |
3051 | * page belonging to that request that is currently residing in our private | |
3052 | * plug. By flushing the pending I/O when the process goes to sleep, we avoid | |
3053 | * this kind of deadlock. | |
3054 | */ | |
3055 | void blk_start_plug(struct blk_plug *plug) | |
3056 | { | |
3057 | struct task_struct *tsk = current; | |
3058 | ||
3059 | /* | |
3060 | * If this is a nested plug, don't actually assign it. | |
3061 | */ | |
3062 | if (tsk->plug) | |
3063 | return; | |
3064 | ||
3065 | INIT_LIST_HEAD(&plug->list); | |
3066 | INIT_LIST_HEAD(&plug->mq_list); | |
3067 | INIT_LIST_HEAD(&plug->cb_list); | |
3068 | /* | |
3069 | * Store ordering should not be needed here, since a potential | |
3070 | * preempt will imply a full memory barrier | |
3071 | */ | |
3072 | tsk->plug = plug; | |
3073 | } | |
3074 | EXPORT_SYMBOL(blk_start_plug); | |
3075 | ||
3076 | static int plug_rq_cmp(void *priv, struct list_head *a, struct list_head *b) | |
3077 | { | |
3078 | struct request *rqa = container_of(a, struct request, queuelist); | |
3079 | struct request *rqb = container_of(b, struct request, queuelist); | |
3080 | ||
3081 | return !(rqa->q < rqb->q || | |
3082 | (rqa->q == rqb->q && blk_rq_pos(rqa) < blk_rq_pos(rqb))); | |
3083 | } | |
3084 | ||
3085 | /* | |
3086 | * If 'from_schedule' is true, then postpone the dispatch of requests | |
3087 | * until a safe kblockd context. We due this to avoid accidental big | |
3088 | * additional stack usage in driver dispatch, in places where the originally | |
3089 | * plugger did not intend it. | |
3090 | */ | |
3091 | static void queue_unplugged(struct request_queue *q, unsigned int depth, | |
3092 | bool from_schedule) | |
3093 | __releases(q->queue_lock) | |
3094 | { | |
3095 | trace_block_unplug(q, depth, !from_schedule); | |
3096 | ||
3097 | if (from_schedule) | |
3098 | blk_run_queue_async(q); | |
3099 | else | |
3100 | __blk_run_queue(q); | |
3101 | spin_unlock(q->queue_lock); | |
3102 | } | |
3103 | ||
3104 | static void flush_plug_callbacks(struct blk_plug *plug, bool from_schedule) | |
3105 | { | |
3106 | LIST_HEAD(callbacks); | |
3107 | ||
3108 | while (!list_empty(&plug->cb_list)) { | |
3109 | list_splice_init(&plug->cb_list, &callbacks); | |
3110 | ||
3111 | while (!list_empty(&callbacks)) { | |
3112 | struct blk_plug_cb *cb = list_first_entry(&callbacks, | |
3113 | struct blk_plug_cb, | |
3114 | list); | |
3115 | list_del(&cb->list); | |
3116 | cb->callback(cb, from_schedule); | |
3117 | } | |
3118 | } | |
3119 | } | |
3120 | ||
3121 | struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug, void *data, | |
3122 | int size) | |
3123 | { | |
3124 | struct blk_plug *plug = current->plug; | |
3125 | struct blk_plug_cb *cb; | |
3126 | ||
3127 | if (!plug) | |
3128 | return NULL; | |
3129 | ||
3130 | list_for_each_entry(cb, &plug->cb_list, list) | |
3131 | if (cb->callback == unplug && cb->data == data) | |
3132 | return cb; | |
3133 | ||
3134 | /* Not currently on the callback list */ | |
3135 | BUG_ON(size < sizeof(*cb)); | |
3136 | cb = kzalloc(size, GFP_ATOMIC); | |
3137 | if (cb) { | |
3138 | cb->data = data; | |
3139 | cb->callback = unplug; | |
3140 | list_add(&cb->list, &plug->cb_list); | |
3141 | } | |
3142 | return cb; | |
3143 | } | |
3144 | EXPORT_SYMBOL(blk_check_plugged); | |
3145 | ||
3146 | void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule) | |
3147 | { | |
3148 | struct request_queue *q; | |
3149 | unsigned long flags; | |
3150 | struct request *rq; | |
3151 | LIST_HEAD(list); | |
3152 | unsigned int depth; | |
3153 | ||
3154 | flush_plug_callbacks(plug, from_schedule); | |
3155 | ||
3156 | if (!list_empty(&plug->mq_list)) | |
3157 | blk_mq_flush_plug_list(plug, from_schedule); | |
3158 | ||
3159 | if (list_empty(&plug->list)) | |
3160 | return; | |
3161 | ||
3162 | list_splice_init(&plug->list, &list); | |
3163 | ||
3164 | list_sort(NULL, &list, plug_rq_cmp); | |
3165 | ||
3166 | q = NULL; | |
3167 | depth = 0; | |
3168 | ||
3169 | /* | |
3170 | * Save and disable interrupts here, to avoid doing it for every | |
3171 | * queue lock we have to take. | |
3172 | */ | |
3173 | local_irq_save(flags); | |
3174 | while (!list_empty(&list)) { | |
3175 | rq = list_entry_rq(list.next); | |
3176 | list_del_init(&rq->queuelist); | |
3177 | BUG_ON(!rq->q); | |
3178 | if (rq->q != q) { | |
3179 | /* | |
3180 | * This drops the queue lock | |
3181 | */ | |
3182 | if (q) | |
3183 | queue_unplugged(q, depth, from_schedule); | |
3184 | q = rq->q; | |
3185 | depth = 0; | |
3186 | spin_lock(q->queue_lock); | |
3187 | } | |
3188 | ||
3189 | /* | |
3190 | * Short-circuit if @q is dead | |
3191 | */ | |
3192 | if (unlikely(blk_queue_dying(q))) { | |
3193 | __blk_end_request_all(rq, -ENODEV); | |
3194 | continue; | |
3195 | } | |
3196 | ||
3197 | /* | |
3198 | * rq is already accounted, so use raw insert | |
3199 | */ | |
3200 | if (rq->cmd_flags & (REQ_FLUSH | REQ_FUA)) | |
3201 | __elv_add_request(q, rq, ELEVATOR_INSERT_FLUSH); | |
3202 | else | |
3203 | __elv_add_request(q, rq, ELEVATOR_INSERT_SORT_MERGE); | |
3204 | ||
3205 | depth++; | |
3206 | } | |
3207 | ||
3208 | /* | |
3209 | * This drops the queue lock | |
3210 | */ | |
3211 | if (q) | |
3212 | queue_unplugged(q, depth, from_schedule); | |
3213 | ||
3214 | local_irq_restore(flags); | |
3215 | } | |
3216 | ||
3217 | void blk_finish_plug(struct blk_plug *plug) | |
3218 | { | |
3219 | if (plug != current->plug) | |
3220 | return; | |
3221 | blk_flush_plug_list(plug, false); | |
3222 | ||
3223 | current->plug = NULL; | |
3224 | } | |
3225 | EXPORT_SYMBOL(blk_finish_plug); | |
3226 | ||
3227 | #ifdef CONFIG_PM | |
3228 | /** | |
3229 | * blk_pm_runtime_init - Block layer runtime PM initialization routine | |
3230 | * @q: the queue of the device | |
3231 | * @dev: the device the queue belongs to | |
3232 | * | |
3233 | * Description: | |
3234 | * Initialize runtime-PM-related fields for @q and start auto suspend for | |
3235 | * @dev. Drivers that want to take advantage of request-based runtime PM | |
3236 | * should call this function after @dev has been initialized, and its | |
3237 | * request queue @q has been allocated, and runtime PM for it can not happen | |
3238 | * yet(either due to disabled/forbidden or its usage_count > 0). In most | |
3239 | * cases, driver should call this function before any I/O has taken place. | |
3240 | * | |
3241 | * This function takes care of setting up using auto suspend for the device, | |
3242 | * the autosuspend delay is set to -1 to make runtime suspend impossible | |
3243 | * until an updated value is either set by user or by driver. Drivers do | |
3244 | * not need to touch other autosuspend settings. | |
3245 | * | |
3246 | * The block layer runtime PM is request based, so only works for drivers | |
3247 | * that use request as their IO unit instead of those directly use bio's. | |
3248 | */ | |
3249 | void blk_pm_runtime_init(struct request_queue *q, struct device *dev) | |
3250 | { | |
3251 | q->dev = dev; | |
3252 | q->rpm_status = RPM_ACTIVE; | |
3253 | pm_runtime_set_autosuspend_delay(q->dev, -1); | |
3254 | pm_runtime_use_autosuspend(q->dev); | |
3255 | } | |
3256 | EXPORT_SYMBOL(blk_pm_runtime_init); | |
3257 | ||
3258 | /** | |
3259 | * blk_pre_runtime_suspend - Pre runtime suspend check | |
3260 | * @q: the queue of the device | |
3261 | * | |
3262 | * Description: | |
3263 | * This function will check if runtime suspend is allowed for the device | |
3264 | * by examining if there are any requests pending in the queue. If there | |
3265 | * are requests pending, the device can not be runtime suspended; otherwise, | |
3266 | * the queue's status will be updated to SUSPENDING and the driver can | |
3267 | * proceed to suspend the device. | |
3268 | * | |
3269 | * For the not allowed case, we mark last busy for the device so that | |
3270 | * runtime PM core will try to autosuspend it some time later. | |
3271 | * | |
3272 | * This function should be called near the start of the device's | |
3273 | * runtime_suspend callback. | |
3274 | * | |
3275 | * Return: | |
3276 | * 0 - OK to runtime suspend the device | |
3277 | * -EBUSY - Device should not be runtime suspended | |
3278 | */ | |
3279 | int blk_pre_runtime_suspend(struct request_queue *q) | |
3280 | { | |
3281 | int ret = 0; | |
3282 | ||
3283 | spin_lock_irq(q->queue_lock); | |
3284 | if (q->nr_pending) { | |
3285 | ret = -EBUSY; | |
3286 | pm_runtime_mark_last_busy(q->dev); | |
3287 | } else { | |
3288 | q->rpm_status = RPM_SUSPENDING; | |
3289 | } | |
3290 | spin_unlock_irq(q->queue_lock); | |
3291 | return ret; | |
3292 | } | |
3293 | EXPORT_SYMBOL(blk_pre_runtime_suspend); | |
3294 | ||
3295 | /** | |
3296 | * blk_post_runtime_suspend - Post runtime suspend processing | |
3297 | * @q: the queue of the device | |
3298 | * @err: return value of the device's runtime_suspend function | |
3299 | * | |
3300 | * Description: | |
3301 | * Update the queue's runtime status according to the return value of the | |
3302 | * device's runtime suspend function and mark last busy for the device so | |
3303 | * that PM core will try to auto suspend the device at a later time. | |
3304 | * | |
3305 | * This function should be called near the end of the device's | |
3306 | * runtime_suspend callback. | |
3307 | */ | |
3308 | void blk_post_runtime_suspend(struct request_queue *q, int err) | |
3309 | { | |
3310 | spin_lock_irq(q->queue_lock); | |
3311 | if (!err) { | |
3312 | q->rpm_status = RPM_SUSPENDED; | |
3313 | } else { | |
3314 | q->rpm_status = RPM_ACTIVE; | |
3315 | pm_runtime_mark_last_busy(q->dev); | |
3316 | } | |
3317 | spin_unlock_irq(q->queue_lock); | |
3318 | } | |
3319 | EXPORT_SYMBOL(blk_post_runtime_suspend); | |
3320 | ||
3321 | /** | |
3322 | * blk_pre_runtime_resume - Pre runtime resume processing | |
3323 | * @q: the queue of the device | |
3324 | * | |
3325 | * Description: | |
3326 | * Update the queue's runtime status to RESUMING in preparation for the | |
3327 | * runtime resume of the device. | |
3328 | * | |
3329 | * This function should be called near the start of the device's | |
3330 | * runtime_resume callback. | |
3331 | */ | |
3332 | void blk_pre_runtime_resume(struct request_queue *q) | |
3333 | { | |
3334 | spin_lock_irq(q->queue_lock); | |
3335 | q->rpm_status = RPM_RESUMING; | |
3336 | spin_unlock_irq(q->queue_lock); | |
3337 | } | |
3338 | EXPORT_SYMBOL(blk_pre_runtime_resume); | |
3339 | ||
3340 | /** | |
3341 | * blk_post_runtime_resume - Post runtime resume processing | |
3342 | * @q: the queue of the device | |
3343 | * @err: return value of the device's runtime_resume function | |
3344 | * | |
3345 | * Description: | |
3346 | * Update the queue's runtime status according to the return value of the | |
3347 | * device's runtime_resume function. If it is successfully resumed, process | |
3348 | * the requests that are queued into the device's queue when it is resuming | |
3349 | * and then mark last busy and initiate autosuspend for it. | |
3350 | * | |
3351 | * This function should be called near the end of the device's | |
3352 | * runtime_resume callback. | |
3353 | */ | |
3354 | void blk_post_runtime_resume(struct request_queue *q, int err) | |
3355 | { | |
3356 | spin_lock_irq(q->queue_lock); | |
3357 | if (!err) { | |
3358 | q->rpm_status = RPM_ACTIVE; | |
3359 | __blk_run_queue(q); | |
3360 | pm_runtime_mark_last_busy(q->dev); | |
3361 | pm_request_autosuspend(q->dev); | |
3362 | } else { | |
3363 | q->rpm_status = RPM_SUSPENDED; | |
3364 | } | |
3365 | spin_unlock_irq(q->queue_lock); | |
3366 | } | |
3367 | EXPORT_SYMBOL(blk_post_runtime_resume); | |
3368 | #endif | |
3369 | ||
3370 | int __init blk_dev_init(void) | |
3371 | { | |
3372 | BUILD_BUG_ON(__REQ_NR_BITS > 8 * | |
3373 | FIELD_SIZEOF(struct request, cmd_flags)); | |
3374 | ||
3375 | /* used for unplugging and affects IO latency/throughput - HIGHPRI */ | |
3376 | kblockd_workqueue = alloc_workqueue("kblockd", | |
3377 | WQ_MEM_RECLAIM | WQ_HIGHPRI, 0); | |
3378 | if (!kblockd_workqueue) | |
3379 | panic("Failed to create kblockd\n"); | |
3380 | ||
3381 | request_cachep = kmem_cache_create("blkdev_requests", | |
3382 | sizeof(struct request), 0, SLAB_PANIC, NULL); | |
3383 | ||
3384 | blk_requestq_cachep = kmem_cache_create("blkdev_queue", | |
3385 | sizeof(struct request_queue), 0, SLAB_PANIC, NULL); | |
3386 | ||
3387 | return 0; | |
3388 | } |