Branch data Line data Source code
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 : :
36 : : #define CREATE_TRACE_POINTS
37 : : #include <trace/events/block.h>
38 : :
39 : : #include "blk.h"
40 : : #include "blk-cgroup.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_unplug);
47 : :
48 : : DEFINE_IDA(blk_queue_ida);
49 : :
50 : : /*
51 : : * For the allocated request tables
52 : : */
53 : : struct kmem_cache *request_cachep = NULL;
54 : :
55 : : /*
56 : : * For queue allocation
57 : : */
58 : : struct kmem_cache *blk_requestq_cachep;
59 : :
60 : : /*
61 : : * Controlling structure to kblockd
62 : : */
63 : : static struct workqueue_struct *kblockd_workqueue;
64 : :
65 : 0 : void blk_queue_congestion_threshold(struct request_queue *q)
66 : : {
67 : : int nr;
68 : :
69 : 0 : nr = q->nr_requests - (q->nr_requests / 8) + 1;
70 [ # # ]: 0 : if (nr > q->nr_requests)
71 : 0 : nr = q->nr_requests;
72 : 0 : q->nr_congestion_on = nr;
73 : :
74 : 0 : nr = q->nr_requests - (q->nr_requests / 8) - (q->nr_requests / 16) - 1;
75 [ # # ]: 0 : if (nr < 1)
76 : : nr = 1;
77 : 0 : q->nr_congestion_off = nr;
78 : 0 : }
79 : :
80 : : /**
81 : : * blk_get_backing_dev_info - get the address of a queue's backing_dev_info
82 : : * @bdev: device
83 : : *
84 : : * Locates the passed device's request queue and returns the address of its
85 : : * backing_dev_info
86 : : *
87 : : * Will return NULL if the request queue cannot be located.
88 : : */
89 : 0 : struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev)
90 : : {
91 : : struct backing_dev_info *ret = NULL;
92 : : struct request_queue *q = bdev_get_queue(bdev);
93 : :
94 [ + - ]: 149 : if (q)
95 : 149 : ret = &q->backing_dev_info;
96 : 0 : return ret;
97 : : }
98 : : EXPORT_SYMBOL(blk_get_backing_dev_info);
99 : :
100 : 0 : void blk_rq_init(struct request_queue *q, struct request *rq)
101 : : {
102 : 402826 : memset(rq, 0, sizeof(*rq));
103 : :
104 : 402823 : INIT_LIST_HEAD(&rq->queuelist);
105 : 402823 : INIT_LIST_HEAD(&rq->timeout_list);
106 : 402823 : rq->cpu = -1;
107 : 402823 : rq->q = q;
108 : 402823 : rq->__sector = (sector_t) -1;
109 : : INIT_HLIST_NODE(&rq->hash);
110 : 402823 : RB_CLEAR_NODE(&rq->rb_node);
111 : 402823 : rq->cmd = rq->__cmd;
112 : 402823 : rq->cmd_len = BLK_MAX_CDB;
113 : 402823 : rq->tag = -1;
114 : 402823 : rq->start_time = jiffies;
115 : : set_start_time_ns(rq);
116 : 402823 : rq->part = NULL;
117 : 402823 : }
118 : : EXPORT_SYMBOL(blk_rq_init);
119 : :
120 : 0 : static void req_bio_endio(struct request *rq, struct bio *bio,
121 : : unsigned int nbytes, int error)
122 : : {
123 [ - + ]: 454917 : if (error)
124 : 0 : clear_bit(BIO_UPTODATE, &bio->bi_flags);
125 [ - + ]: 454917 : else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
126 : : error = -EIO;
127 : :
128 [ - + ]: 454917 : if (unlikely(rq->cmd_flags & REQ_QUIET))
129 : 0 : set_bit(BIO_QUIET, &bio->bi_flags);
130 : :
131 : 454917 : bio_advance(bio, nbytes);
132 : :
133 : : /* don't actually finish bio if it's part of flush sequence */
134 [ + - ][ + - ]: 454917 : if (bio->bi_iter.bi_size == 0 && !(rq->cmd_flags & REQ_FLUSH_SEQ))
135 : 454917 : bio_endio(bio, error);
136 : 0 : }
137 : :
138 : 0 : void blk_dump_rq_flags(struct request *rq, char *msg)
139 : : {
140 : : int bit;
141 : :
142 [ # # ]: 0 : printk(KERN_INFO "%s: dev %s: type=%x, flags=%llx\n", msg,
143 : 0 : rq->rq_disk ? rq->rq_disk->disk_name : "?", rq->cmd_type,
144 : : (unsigned long long) rq->cmd_flags);
145 : :
146 : 0 : printk(KERN_INFO " sector %llu, nr/cnr %u/%u\n",
147 : : (unsigned long long)blk_rq_pos(rq),
148 : : blk_rq_sectors(rq), blk_rq_cur_sectors(rq));
149 : 0 : printk(KERN_INFO " bio %p, biotail %p, buffer %p, len %u\n",
150 : : rq->bio, rq->biotail, rq->buffer, blk_rq_bytes(rq));
151 : :
152 [ # # ]: 0 : if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
153 : 0 : printk(KERN_INFO " cdb: ");
154 [ # # ]: 0 : for (bit = 0; bit < BLK_MAX_CDB; bit++)
155 : 0 : printk("%02x ", rq->cmd[bit]);
156 : 0 : printk("\n");
157 : : }
158 : 0 : }
159 : : EXPORT_SYMBOL(blk_dump_rq_flags);
160 : :
161 : 0 : static void blk_delay_work(struct work_struct *work)
162 : : {
163 : : struct request_queue *q;
164 : :
165 : 1233 : q = container_of(work, struct request_queue, delay_work.work);
166 : 1233 : spin_lock_irq(q->queue_lock);
167 : 1233 : __blk_run_queue(q);
168 : 1233 : spin_unlock_irq(q->queue_lock);
169 : 1233 : }
170 : :
171 : : /**
172 : : * blk_delay_queue - restart queueing after defined interval
173 : : * @q: The &struct request_queue in question
174 : : * @msecs: Delay in msecs
175 : : *
176 : : * Description:
177 : : * Sometimes queueing needs to be postponed for a little while, to allow
178 : : * resources to come back. This function will make sure that queueing is
179 : : * restarted around the specified time. Queue lock must be held.
180 : : */
181 : 0 : void blk_delay_queue(struct request_queue *q, unsigned long msecs)
182 : : {
183 [ # # ]: 0 : if (likely(!blk_queue_dead(q)))
184 : 0 : queue_delayed_work(kblockd_workqueue, &q->delay_work,
185 : : msecs_to_jiffies(msecs));
186 : 0 : }
187 : : EXPORT_SYMBOL(blk_delay_queue);
188 : :
189 : : /**
190 : : * blk_start_queue - restart a previously stopped queue
191 : : * @q: The &struct request_queue in question
192 : : *
193 : : * Description:
194 : : * blk_start_queue() will clear the stop flag on the queue, and call
195 : : * the request_fn for the queue if it was in a stopped state when
196 : : * entered. Also see blk_stop_queue(). Queue lock must be held.
197 : : **/
198 : 0 : void blk_start_queue(struct request_queue *q)
199 : : {
200 [ # # ]: 0 : WARN_ON(!irqs_disabled());
201 : :
202 : : queue_flag_clear(QUEUE_FLAG_STOPPED, q);
203 : 0 : __blk_run_queue(q);
204 : 0 : }
205 : : EXPORT_SYMBOL(blk_start_queue);
206 : :
207 : : /**
208 : : * blk_stop_queue - stop a queue
209 : : * @q: The &struct request_queue in question
210 : : *
211 : : * Description:
212 : : * The Linux block layer assumes that a block driver will consume all
213 : : * entries on the request queue when the request_fn strategy is called.
214 : : * Often this will not happen, because of hardware limitations (queue
215 : : * depth settings). If a device driver gets a 'queue full' response,
216 : : * or if it simply chooses not to queue more I/O at one point, it can
217 : : * call this function to prevent the request_fn from being called until
218 : : * the driver has signalled it's ready to go again. This happens by calling
219 : : * blk_start_queue() to restart queue operations. Queue lock must be held.
220 : : **/
221 : 0 : void blk_stop_queue(struct request_queue *q)
222 : : {
223 : 0 : cancel_delayed_work(&q->delay_work);
224 : : queue_flag_set(QUEUE_FLAG_STOPPED, q);
225 : 0 : }
226 : : EXPORT_SYMBOL(blk_stop_queue);
227 : :
228 : : /**
229 : : * blk_sync_queue - cancel any pending callbacks on a queue
230 : : * @q: the queue
231 : : *
232 : : * Description:
233 : : * The block layer may perform asynchronous callback activity
234 : : * on a queue, such as calling the unplug function after a timeout.
235 : : * A block device may call blk_sync_queue to ensure that any
236 : : * such activity is cancelled, thus allowing it to release resources
237 : : * that the callbacks might use. The caller must already have made sure
238 : : * that its ->make_request_fn will not re-add plugging prior to calling
239 : : * this function.
240 : : *
241 : : * This function does not cancel any asynchronous activity arising
242 : : * out of elevator or throttling code. That would require elevaotor_exit()
243 : : * and blkcg_exit_queue() to be called with queue lock initialized.
244 : : *
245 : : */
246 : 0 : void blk_sync_queue(struct request_queue *q)
247 : : {
248 : 0 : del_timer_sync(&q->timeout);
249 : :
250 [ # # ]: 0 : if (q->mq_ops) {
251 : : struct blk_mq_hw_ctx *hctx;
252 : : int i;
253 : :
254 [ # # ]: 0 : queue_for_each_hw_ctx(q, hctx, i)
255 : 0 : cancel_delayed_work_sync(&hctx->delayed_work);
256 : : } else {
257 : 0 : cancel_delayed_work_sync(&q->delay_work);
258 : : }
259 : 0 : }
260 : : EXPORT_SYMBOL(blk_sync_queue);
261 : :
262 : : /**
263 : : * __blk_run_queue_uncond - run a queue whether or not it has been stopped
264 : : * @q: The queue to run
265 : : *
266 : : * Description:
267 : : * Invoke request handling on a queue if there are any pending requests.
268 : : * May be used to restart request handling after a request has completed.
269 : : * This variant runs the queue whether or not the queue has been
270 : : * stopped. Must be called with the queue lock held and interrupts
271 : : * disabled. See also @blk_run_queue.
272 : : */
273 : 0 : inline void __blk_run_queue_uncond(struct request_queue *q)
274 : : {
275 [ + - ][ # # ]: 941041 : if (unlikely(blk_queue_dead(q)))
276 : 0 : return;
277 : :
278 : : /*
279 : : * Some request_fn implementations, e.g. scsi_request_fn(), unlock
280 : : * the queue lock internally. As a result multiple threads may be
281 : : * running such a request function concurrently. Keep track of the
282 : : * number of active request_fn invocations such that blk_drain_queue()
283 : : * can wait until all these request_fn calls have finished.
284 : : */
285 : 941041 : q->request_fn_active++;
286 : 941041 : q->request_fn(q);
287 : 941041 : q->request_fn_active--;
288 : : }
289 : :
290 : : /**
291 : : * __blk_run_queue - run a single device queue
292 : : * @q: The queue to run
293 : : *
294 : : * Description:
295 : : * See @blk_run_queue. This variant must be called with the queue lock
296 : : * held and interrupts disabled.
297 : : */
298 : 0 : void __blk_run_queue(struct request_queue *q)
299 : : {
300 [ + - ]: 941041 : if (unlikely(blk_queue_stopped(q)))
301 : 0 : return;
302 : :
303 : : __blk_run_queue_uncond(q);
304 : : }
305 : : EXPORT_SYMBOL(__blk_run_queue);
306 : :
307 : : /**
308 : : * blk_run_queue_async - run a single device queue in workqueue context
309 : : * @q: The queue to run
310 : : *
311 : : * Description:
312 : : * Tells kblockd to perform the equivalent of @blk_run_queue on behalf
313 : : * of us. The caller must hold the queue lock.
314 : : */
315 : 0 : void blk_run_queue_async(struct request_queue *q)
316 : : {
317 [ + - ][ + - ]: 1233 : if (likely(!blk_queue_stopped(q) && !blk_queue_dead(q)))
318 : 1233 : mod_delayed_work(kblockd_workqueue, &q->delay_work, 0);
319 : 0 : }
320 : : EXPORT_SYMBOL(blk_run_queue_async);
321 : :
322 : : /**
323 : : * blk_run_queue - run a single device queue
324 : : * @q: The queue to run
325 : : *
326 : : * Description:
327 : : * Invoke request handling on this queue, if it has pending work to do.
328 : : * May be used to restart queueing when a request has completed.
329 : : */
330 : 0 : void blk_run_queue(struct request_queue *q)
331 : : {
332 : : unsigned long flags;
333 : :
334 : 401979 : spin_lock_irqsave(q->queue_lock, flags);
335 : 401979 : __blk_run_queue(q);
336 : 401979 : spin_unlock_irqrestore(q->queue_lock, flags);
337 : 401979 : }
338 : : EXPORT_SYMBOL(blk_run_queue);
339 : :
340 : 0 : void blk_put_queue(struct request_queue *q)
341 : : {
342 : 0 : kobject_put(&q->kobj);
343 : 0 : }
344 : : EXPORT_SYMBOL(blk_put_queue);
345 : :
346 : : /**
347 : : * __blk_drain_queue - drain requests from request_queue
348 : : * @q: queue to drain
349 : : * @drain_all: whether to drain all requests or only the ones w/ ELVPRIV
350 : : *
351 : : * Drain requests from @q. If @drain_all is set, all requests are drained.
352 : : * If not, only ELVPRIV requests are drained. The caller is responsible
353 : : * for ensuring that no new requests which need to be drained are queued.
354 : : */
355 : 0 : static void __blk_drain_queue(struct request_queue *q, bool drain_all)
356 : : __releases(q->queue_lock)
357 : : __acquires(q->queue_lock)
358 : : {
359 : : int i;
360 : :
361 : : lockdep_assert_held(q->queue_lock);
362 : :
363 : : while (true) {
364 : : bool drain = false;
365 : :
366 : : /*
367 : : * The caller might be trying to drain @q before its
368 : : * elevator is initialized.
369 : : */
370 [ # # ]: 0 : if (q->elevator)
371 : 0 : elv_drain_elevator(q);
372 : :
373 : : blkcg_drain_queue(q);
374 : :
375 : : /*
376 : : * This function might be called on a queue which failed
377 : : * driver init after queue creation or is not yet fully
378 : : * active yet. Some drivers (e.g. fd and loop) get unhappy
379 : : * in such cases. Kick queue iff dispatch queue has
380 : : * something on it and @q has request_fn set.
381 : : */
382 [ # # ][ # # ]: 0 : if (!list_empty(&q->queue_head) && q->request_fn)
383 : 0 : __blk_run_queue(q);
384 : :
385 : 0 : drain |= q->nr_rqs_elvpriv;
386 : 0 : drain |= q->request_fn_active;
387 : :
388 : : /*
389 : : * Unfortunately, requests are queued at and tracked from
390 : : * multiple places and there's no single counter which can
391 : : * be drained. Check all the queues and counters.
392 : : */
393 [ # # ]: 0 : if (drain_all) {
394 : 0 : drain |= !list_empty(&q->queue_head);
395 [ # # ]: 0 : for (i = 0; i < 2; i++) {
396 : 0 : drain |= q->nr_rqs[i];
397 : 0 : drain |= q->in_flight[i];
398 : 0 : drain |= !list_empty(&q->flush_queue[i]);
399 : : }
400 : : }
401 : :
402 [ # # ]: 0 : if (!drain)
403 : : break;
404 : :
405 : 0 : spin_unlock_irq(q->queue_lock);
406 : :
407 : 0 : msleep(10);
408 : :
409 : 0 : spin_lock_irq(q->queue_lock);
410 : : }
411 : :
412 : : /*
413 : : * With queue marked dead, any woken up waiter will fail the
414 : : * allocation path, so the wakeup chaining is lost and we're
415 : : * left with hung waiters. We need to wake up those waiters.
416 : : */
417 [ # # ]: 0 : if (q->request_fn) {
418 : : struct request_list *rl;
419 : :
420 [ # # ]: 0 : blk_queue_for_each_rl(rl, q)
421 [ # # ]: 0 : for (i = 0; i < ARRAY_SIZE(rl->wait); i++)
422 : 0 : wake_up_all(&rl->wait[i]);
423 : : }
424 : 0 : }
425 : :
426 : : /**
427 : : * blk_queue_bypass_start - enter queue bypass mode
428 : : * @q: queue of interest
429 : : *
430 : : * In bypass mode, only the dispatch FIFO queue of @q is used. This
431 : : * function makes @q enter bypass mode and drains all requests which were
432 : : * throttled or issued before. On return, it's guaranteed that no request
433 : : * is being throttled or has ELVPRIV set and blk_queue_bypass() %true
434 : : * inside queue or RCU read lock.
435 : : */
436 : 0 : void blk_queue_bypass_start(struct request_queue *q)
437 : : {
438 : : bool drain;
439 : :
440 : 0 : spin_lock_irq(q->queue_lock);
441 : 0 : drain = !q->bypass_depth++;
442 : : queue_flag_set(QUEUE_FLAG_BYPASS, q);
443 : 0 : spin_unlock_irq(q->queue_lock);
444 : :
445 [ # # ]: 0 : if (drain) {
446 : 0 : spin_lock_irq(q->queue_lock);
447 : 0 : __blk_drain_queue(q, false);
448 : 0 : spin_unlock_irq(q->queue_lock);
449 : :
450 : : /* ensure blk_queue_bypass() is %true inside RCU read lock */
451 : : synchronize_rcu();
452 : : }
453 : 0 : }
454 : : EXPORT_SYMBOL_GPL(blk_queue_bypass_start);
455 : :
456 : : /**
457 : : * blk_queue_bypass_end - leave queue bypass mode
458 : : * @q: queue of interest
459 : : *
460 : : * Leave bypass mode and restore the normal queueing behavior.
461 : : */
462 : 0 : void blk_queue_bypass_end(struct request_queue *q)
463 : : {
464 : 0 : spin_lock_irq(q->queue_lock);
465 [ # # ]: 0 : if (!--q->bypass_depth)
466 : : queue_flag_clear(QUEUE_FLAG_BYPASS, q);
467 [ # # ][ # # ]: 0 : WARN_ON_ONCE(q->bypass_depth < 0);
[ # # ]
468 : 0 : spin_unlock_irq(q->queue_lock);
469 : 0 : }
470 : : EXPORT_SYMBOL_GPL(blk_queue_bypass_end);
471 : :
472 : : /**
473 : : * blk_cleanup_queue - shutdown a request queue
474 : : * @q: request queue to shutdown
475 : : *
476 : : * Mark @q DYING, drain all pending requests, mark @q DEAD, destroy and
477 : : * put it. All future requests will be failed immediately with -ENODEV.
478 : : */
479 : 0 : void blk_cleanup_queue(struct request_queue *q)
480 : : {
481 : 0 : spinlock_t *lock = q->queue_lock;
482 : :
483 : : /* mark @q DYING, no new request or merges will be allowed afterwards */
484 : 0 : mutex_lock(&q->sysfs_lock);
485 : : queue_flag_set_unlocked(QUEUE_FLAG_DYING, q);
486 : : spin_lock_irq(lock);
487 : :
488 : : /*
489 : : * A dying queue is permanently in bypass mode till released. Note
490 : : * that, unlike blk_queue_bypass_start(), we aren't performing
491 : : * synchronize_rcu() after entering bypass mode to avoid the delay
492 : : * as some drivers create and destroy a lot of queues while
493 : : * probing. This is still safe because blk_release_queue() will be
494 : : * called only after the queue refcnt drops to zero and nothing,
495 : : * RCU or not, would be traversing the queue by then.
496 : : */
497 : 0 : q->bypass_depth++;
498 : : queue_flag_set(QUEUE_FLAG_BYPASS, q);
499 : :
500 : : queue_flag_set(QUEUE_FLAG_NOMERGES, q);
501 : : queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
502 : : queue_flag_set(QUEUE_FLAG_DYING, q);
503 : : spin_unlock_irq(lock);
504 : 0 : mutex_unlock(&q->sysfs_lock);
505 : :
506 : : /*
507 : : * Drain all requests queued before DYING marking. Set DEAD flag to
508 : : * prevent that q->request_fn() gets invoked after draining finished.
509 : : */
510 [ # # ]: 0 : if (q->mq_ops) {
511 : 0 : blk_mq_drain_queue(q);
512 : : spin_lock_irq(lock);
513 : : } else {
514 : : spin_lock_irq(lock);
515 : 0 : __blk_drain_queue(q, true);
516 : : }
517 : : queue_flag_set(QUEUE_FLAG_DEAD, q);
518 : : spin_unlock_irq(lock);
519 : :
520 : : /* @q won't process any more request, flush async actions */
521 : 0 : del_timer_sync(&q->backing_dev_info.laptop_mode_wb_timer);
522 : 0 : blk_sync_queue(q);
523 : :
524 : : spin_lock_irq(lock);
525 [ # # ]: 0 : if (q->queue_lock != &q->__queue_lock)
526 : 0 : q->queue_lock = &q->__queue_lock;
527 : : spin_unlock_irq(lock);
528 : :
529 : : /* @q is and will stay empty, shutdown and put */
530 : : blk_put_queue(q);
531 : 0 : }
532 : : EXPORT_SYMBOL(blk_cleanup_queue);
533 : :
534 : 0 : int blk_init_rl(struct request_list *rl, struct request_queue *q,
535 : : gfp_t gfp_mask)
536 : : {
537 [ # # ]: 0 : if (unlikely(rl->rq_pool))
538 : : return 0;
539 : :
540 : 0 : rl->q = q;
541 : 0 : rl->count[BLK_RW_SYNC] = rl->count[BLK_RW_ASYNC] = 0;
542 : 0 : rl->starved[BLK_RW_SYNC] = rl->starved[BLK_RW_ASYNC] = 0;
543 : 0 : init_waitqueue_head(&rl->wait[BLK_RW_SYNC]);
544 : 0 : init_waitqueue_head(&rl->wait[BLK_RW_ASYNC]);
545 : :
546 : 0 : rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ, mempool_alloc_slab,
547 : : mempool_free_slab, request_cachep,
548 : : gfp_mask, q->node);
549 [ # # ]: 0 : if (!rl->rq_pool)
550 : : return -ENOMEM;
551 : :
552 : 0 : return 0;
553 : : }
554 : :
555 : 0 : void blk_exit_rl(struct request_list *rl)
556 : : {
557 [ # # ]: 0 : if (rl->rq_pool)
558 : 0 : mempool_destroy(rl->rq_pool);
559 : 0 : }
560 : :
561 : 0 : struct request_queue *blk_alloc_queue(gfp_t gfp_mask)
562 : : {
563 : 0 : return blk_alloc_queue_node(gfp_mask, NUMA_NO_NODE);
564 : : }
565 : : EXPORT_SYMBOL(blk_alloc_queue);
566 : :
567 : 0 : struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
568 : : {
569 : : struct request_queue *q;
570 : : int err;
571 : :
572 : 0 : q = kmem_cache_alloc_node(blk_requestq_cachep,
573 : : gfp_mask | __GFP_ZERO, node_id);
574 [ # # ]: 0 : if (!q)
575 : : return NULL;
576 : :
577 [ # # ]: 0 : if (percpu_counter_init(&q->mq_usage_counter, 0))
578 : : goto fail_q;
579 : :
580 : 0 : q->id = ida_simple_get(&blk_queue_ida, 0, 0, gfp_mask);
581 [ # # ]: 0 : if (q->id < 0)
582 : : goto fail_c;
583 : :
584 : 0 : q->backing_dev_info.ra_pages =
585 : : (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
586 : 0 : q->backing_dev_info.state = 0;
587 : 0 : q->backing_dev_info.capabilities = BDI_CAP_MAP_COPY;
588 : 0 : q->backing_dev_info.name = "block";
589 : 0 : q->node = node_id;
590 : :
591 : 0 : err = bdi_init(&q->backing_dev_info);
592 [ # # ]: 0 : if (err)
593 : : goto fail_id;
594 : :
595 : 0 : setup_timer(&q->backing_dev_info.laptop_mode_wb_timer,
596 : : laptop_mode_timer_fn, (unsigned long) q);
597 : 0 : setup_timer(&q->timeout, blk_rq_timed_out_timer, (unsigned long) q);
598 : 0 : INIT_LIST_HEAD(&q->queue_head);
599 : 0 : INIT_LIST_HEAD(&q->timeout_list);
600 : 0 : INIT_LIST_HEAD(&q->icq_list);
601 : : #ifdef CONFIG_BLK_CGROUP
602 : : INIT_LIST_HEAD(&q->blkg_list);
603 : : #endif
604 : 0 : INIT_LIST_HEAD(&q->flush_queue[0]);
605 : 0 : INIT_LIST_HEAD(&q->flush_queue[1]);
606 : 0 : INIT_LIST_HEAD(&q->flush_data_in_flight);
607 : 0 : INIT_DELAYED_WORK(&q->delay_work, blk_delay_work);
608 : :
609 : 0 : kobject_init(&q->kobj, &blk_queue_ktype);
610 : :
611 : 0 : mutex_init(&q->sysfs_lock);
612 : 0 : spin_lock_init(&q->__queue_lock);
613 : :
614 : : /*
615 : : * By default initialize queue_lock to internal lock and driver can
616 : : * override it later if need be.
617 : : */
618 : 0 : q->queue_lock = &q->__queue_lock;
619 : :
620 : : /*
621 : : * A queue starts its life with bypass turned on to avoid
622 : : * unnecessary bypass on/off overhead and nasty surprises during
623 : : * init. The initial bypass will be finished when the queue is
624 : : * registered by blk_register_queue().
625 : : */
626 : 0 : q->bypass_depth = 1;
627 : : __set_bit(QUEUE_FLAG_BYPASS, &q->queue_flags);
628 : :
629 : 0 : init_waitqueue_head(&q->mq_freeze_wq);
630 : :
631 : : if (blkcg_init_queue(q))
632 : : goto fail_bdi;
633 : :
634 : 0 : return q;
635 : :
636 : : fail_bdi:
637 : : bdi_destroy(&q->backing_dev_info);
638 : : fail_id:
639 : 0 : ida_simple_remove(&blk_queue_ida, q->id);
640 : : fail_c:
641 : 0 : percpu_counter_destroy(&q->mq_usage_counter);
642 : : fail_q:
643 : 0 : kmem_cache_free(blk_requestq_cachep, q);
644 : 0 : return NULL;
645 : : }
646 : : EXPORT_SYMBOL(blk_alloc_queue_node);
647 : :
648 : : /**
649 : : * blk_init_queue - prepare a request queue for use with a block device
650 : : * @rfn: The function to be called to process requests that have been
651 : : * placed on the queue.
652 : : * @lock: Request queue spin lock
653 : : *
654 : : * Description:
655 : : * If a block device wishes to use the standard request handling procedures,
656 : : * which sorts requests and coalesces adjacent requests, then it must
657 : : * call blk_init_queue(). The function @rfn will be called when there
658 : : * are requests on the queue that need to be processed. If the device
659 : : * supports plugging, then @rfn may not be called immediately when requests
660 : : * are available on the queue, but may be called at some time later instead.
661 : : * Plugged queues are generally unplugged when a buffer belonging to one
662 : : * of the requests on the queue is needed, or due to memory pressure.
663 : : *
664 : : * @rfn is not required, or even expected, to remove all requests off the
665 : : * queue, but only as many as it can handle at a time. If it does leave
666 : : * requests on the queue, it is responsible for arranging that the requests
667 : : * get dealt with eventually.
668 : : *
669 : : * The queue spin lock must be held while manipulating the requests on the
670 : : * request queue; this lock will be taken also from interrupt context, so irq
671 : : * disabling is needed for it.
672 : : *
673 : : * Function returns a pointer to the initialized request queue, or %NULL if
674 : : * it didn't succeed.
675 : : *
676 : : * Note:
677 : : * blk_init_queue() must be paired with a blk_cleanup_queue() call
678 : : * when the block device is deactivated (such as at module unload).
679 : : **/
680 : :
681 : 0 : struct request_queue *blk_init_queue(request_fn_proc *rfn, spinlock_t *lock)
682 : : {
683 : 0 : return blk_init_queue_node(rfn, lock, NUMA_NO_NODE);
684 : : }
685 : : EXPORT_SYMBOL(blk_init_queue);
686 : :
687 : : struct request_queue *
688 : 0 : blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id)
689 : : {
690 : : struct request_queue *uninit_q, *q;
691 : :
692 : 0 : uninit_q = blk_alloc_queue_node(GFP_KERNEL, node_id);
693 [ # # ]: 0 : if (!uninit_q)
694 : : return NULL;
695 : :
696 : 0 : q = blk_init_allocated_queue(uninit_q, rfn, lock);
697 [ # # ]: 0 : if (!q)
698 : 0 : blk_cleanup_queue(uninit_q);
699 : :
700 : 0 : return q;
701 : : }
702 : : EXPORT_SYMBOL(blk_init_queue_node);
703 : :
704 : : struct request_queue *
705 : 0 : blk_init_allocated_queue(struct request_queue *q, request_fn_proc *rfn,
706 : : spinlock_t *lock)
707 : : {
708 [ # # ]: 0 : if (!q)
709 : : return NULL;
710 : :
711 : 0 : q->flush_rq = kzalloc(sizeof(struct request), GFP_KERNEL);
712 [ # # ]: 0 : if (!q->flush_rq)
713 : : return NULL;
714 : :
715 [ # # ]: 0 : if (blk_init_rl(&q->root_rl, q, GFP_KERNEL))
716 : : goto fail;
717 : :
718 : 0 : q->request_fn = rfn;
719 : 0 : q->prep_rq_fn = NULL;
720 : 0 : q->unprep_rq_fn = NULL;
721 : 0 : q->queue_flags |= QUEUE_FLAG_DEFAULT;
722 : :
723 : : /* Override internal queue lock with supplied lock pointer */
724 [ # # ]: 0 : if (lock)
725 : 0 : q->queue_lock = lock;
726 : :
727 : : /*
728 : : * This also sets hw/phys segments, boundary and size
729 : : */
730 : 0 : blk_queue_make_request(q, blk_queue_bio);
731 : :
732 : 0 : q->sg_reserved_size = INT_MAX;
733 : :
734 : : /* Protect q->elevator from elevator_change */
735 : 0 : mutex_lock(&q->sysfs_lock);
736 : :
737 : : /* init elevator */
738 [ # # ]: 0 : if (elevator_init(q, NULL)) {
739 : 0 : mutex_unlock(&q->sysfs_lock);
740 : 0 : goto fail;
741 : : }
742 : :
743 : 0 : mutex_unlock(&q->sysfs_lock);
744 : :
745 : 0 : return q;
746 : :
747 : : fail:
748 : 0 : kfree(q->flush_rq);
749 : 0 : return NULL;
750 : : }
751 : : EXPORT_SYMBOL(blk_init_allocated_queue);
752 : :
753 : 0 : bool blk_get_queue(struct request_queue *q)
754 : : {
755 [ # # ]: 0 : if (likely(!blk_queue_dying(q))) {
756 : : __blk_get_queue(q);
757 : 0 : return true;
758 : : }
759 : :
760 : : return false;
761 : : }
762 : : EXPORT_SYMBOL(blk_get_queue);
763 : :
764 : : static inline void blk_free_request(struct request_list *rl, struct request *rq)
765 : : {
766 [ + - ]: 402828 : if (rq->cmd_flags & REQ_ELVPRIV) {
767 : 402828 : elv_put_request(rl->q, rq);
768 [ + - ]: 402828 : if (rq->elv.icq)
769 : 402828 : put_io_context(rq->elv.icq->ioc);
770 : : }
771 : :
772 : 402828 : mempool_free(rq, rl->rq_pool);
773 : : }
774 : :
775 : : /*
776 : : * ioc_batching returns true if the ioc is a valid batching request and
777 : : * should be given priority access to a request.
778 : : */
779 : : static inline int ioc_batching(struct request_queue *q, struct io_context *ioc)
780 : : {
781 [ + - ][ + + ]: 821407 : if (!ioc)
[ + - ]
782 : : return 0;
783 : :
784 : : /*
785 : : * Make sure the process is able to allocate at least 1 request
786 : : * even if the batch times out, otherwise we could theoretically
787 : : * lose wakeups.
788 : : */
789 [ + - ][ + + ]: 417905 : return ioc->nr_batch_requests == q->nr_batching ||
[ + + ][ + + ]
[ + + ][ + + ]
790 : : (ioc->nr_batch_requests > 0
791 [ + + ][ + + ]: 71743 : && time_before(jiffies, ioc->last_waited + BLK_BATCH_TIME));
[ + + ]
792 : : }
793 : :
794 : : /*
795 : : * ioc_set_batching sets ioc to be a new "batcher" if it is not one. This
796 : : * will cause the process to be a "batcher" on all queues in the system. This
797 : : * is the behaviour we want though - once it gets a wakeup it should be given
798 : : * a nice run.
799 : : */
800 : 0 : static void ioc_set_batching(struct request_queue *q, struct io_context *ioc)
801 : : {
802 [ + - ][ + ]: 3100 : if (!ioc || ioc_batching(q, ioc))
803 : 0 : return;
804 : :
805 : 793 : ioc->nr_batch_requests = q->nr_batching;
806 : 793 : ioc->last_waited = jiffies;
807 : : }
808 : :
809 : 0 : static void __freed_request(struct request_list *rl, int sync)
810 : : {
811 : 805656 : struct request_queue *q = rl->q;
812 : :
813 : : /*
814 : : * bdi isn't aware of blkcg yet. As all async IOs end up root
815 : : * blkcg anyway, just use root blkcg state.
816 : : */
817 [ + - ][ + + ]: 402828 : if (rl == &q->root_rl &&
818 : 402828 : rl->count[sync] < queue_congestion_off_threshold(q))
819 : : blk_clear_queue_congested(q, sync);
820 : :
821 [ + + ]: 402828 : if (rl->count[sync] + 1 <= q->nr_requests) {
822 [ + + ]: 390031 : if (waitqueue_active(&rl->wait[sync]))
823 : 750 : wake_up(&rl->wait[sync]);
824 : :
825 : : blk_clear_rl_full(rl, sync);
826 : : }
827 : 402828 : }
828 : :
829 : : /*
830 : : * A request has just been released. Account for it, update the full and
831 : : * congestion status, wake up any waiters. Called under q->queue_lock.
832 : : */
833 : 0 : static void freed_request(struct request_list *rl, unsigned int flags)
834 : : {
835 : 402828 : struct request_queue *q = rl->q;
836 : 402828 : int sync = rw_is_sync(flags);
837 : :
838 : 402828 : q->nr_rqs[sync]--;
839 : 402828 : rl->count[sync]--;
840 [ + - ]: 402828 : if (flags & REQ_ELVPRIV)
841 : 402828 : q->nr_rqs_elvpriv--;
842 : :
843 : 402828 : __freed_request(rl, sync);
844 : :
845 [ - + ]: 402828 : if (unlikely(rl->starved[sync ^ 1]))
846 : 0 : __freed_request(rl, sync ^ 1);
847 : 402828 : }
848 : :
849 : : /*
850 : : * Determine if elevator data should be initialized when allocating the
851 : : * request associated with @bio.
852 : : */
853 : : static bool blk_rq_should_init_elevator(struct bio *bio)
854 : : {
855 [ + + ]: 402828 : if (!bio)
856 : : return true;
857 : :
858 : : /*
859 : : * Flush requests do not use the elevator so skip initialization.
860 : : * This allows a request to share the flush and elevator data.
861 : : */
862 [ + - ]: 387952 : if (bio->bi_rw & (REQ_FLUSH | REQ_FUA))
863 : : return false;
864 : :
865 : : return true;
866 : : }
867 : :
868 : : /**
869 : : * rq_ioc - determine io_context for request allocation
870 : : * @bio: request being allocated is for this bio (can be %NULL)
871 : : *
872 : : * Determine io_context to use for request allocation for @bio. May return
873 : : * %NULL if %current->io_context doesn't exist.
874 : : */
875 : : static struct io_context *rq_ioc(struct bio *bio)
876 : : {
877 : : #ifdef CONFIG_BLK_CGROUP
878 : : if (bio && bio->bi_ioc)
879 : : return bio->bi_ioc;
880 : : #endif
881 : 403578 : return current->io_context;
882 : : }
883 : :
884 : : /**
885 : : * __get_request - get a free request
886 : : * @rl: request list to allocate from
887 : : * @rw_flags: RW and SYNC flags
888 : : * @bio: bio to allocate request for (can be %NULL)
889 : : * @gfp_mask: allocation mask
890 : : *
891 : : * Get a free request from @q. This function may fail under memory
892 : : * pressure or if @q is dead.
893 : : *
894 : : * Must be callled with @q->queue_lock held and,
895 : : * Returns %NULL on failure, with @q->queue_lock held.
896 : : * Returns !%NULL on success, with @q->queue_lock *not held*.
897 : : */
898 : 0 : static struct request *__get_request(struct request_list *rl, int rw_flags,
899 : : struct bio *bio, gfp_t gfp_mask)
900 : : {
901 : 807156 : struct request_queue *q = rl->q;
902 : : struct request *rq;
903 : 403578 : struct elevator_type *et = q->elevator->type;
904 : : struct io_context *ioc = rq_ioc(bio);
905 : : struct io_cq *icq = NULL;
906 : 403578 : const bool is_sync = rw_is_sync(rw_flags) != 0;
907 : : int may_queue;
908 : :
909 [ + - ]: 403578 : if (unlikely(blk_queue_dying(q)))
910 : : return NULL;
911 : :
912 : 403578 : may_queue = elv_may_queue(q, rw_flags);
913 [ + - ]: 403578 : if (may_queue == ELV_MQUEUE_NO)
914 : : goto rq_starved;
915 : :
916 [ + + ]: 403578 : if (rl->count[is_sync]+1 >= queue_congestion_on_threshold(q)) {
917 [ + + ]: 14849 : if (rl->count[is_sync]+1 >= q->nr_requests) {
918 : : /*
919 : : * The queue will fill after this allocation, so set
920 : : * it as full, and mark this process as "batching".
921 : : * This process will be allowed to complete a batch of
922 : : * requests, others will be blocked.
923 : : */
924 [ + + ]: 14347 : if (!blk_rl_full(rl, is_sync)) {
925 : 800 : ioc_set_batching(q, ioc);
926 : : blk_set_rl_full(rl, is_sync);
927 : : } else {
928 [ + - ]: 13547 : if (may_queue != ELV_MQUEUE_MUST
929 [ + + ]: 13547 : && !ioc_batching(q, ioc)) {
930 : : /*
931 : : * The queue is full and the allocating
932 : : * process is not a "batcher", and not
933 : : * exempted by the IO scheduler
934 : : */
935 : : return NULL;
936 : : }
937 : : }
938 : : }
939 : : /*
940 : : * bdi isn't aware of blkcg yet. As all async IOs end up
941 : : * root blkcg anyway, just use root blkcg state.
942 : : */
943 [ + - ]: 14099 : if (rl == &q->root_rl)
944 : : blk_set_queue_congested(q, is_sync);
945 : : }
946 : :
947 : : /*
948 : : * Only allow batching queuers to allocate up to 50% over the defined
949 : : * limit of requests, otherwise we could have thousands of requests
950 : : * allocated with any setting of ->nr_requests
951 : : */
952 [ + - ]: 402828 : if (rl->count[is_sync] >= (3 * q->nr_requests / 2))
953 : : return NULL;
954 : :
955 : 402828 : q->nr_rqs[is_sync]++;
956 : 402828 : rl->count[is_sync]++;
957 : 402828 : rl->starved[is_sync] = 0;
958 : :
959 : : /*
960 : : * Decide whether the new request will be managed by elevator. If
961 : : * so, mark @rw_flags and increment elvpriv. Non-zero elvpriv will
962 : : * prevent the current elevator from being destroyed until the new
963 : : * request is freed. This guarantees icq's won't be destroyed and
964 : : * makes creating new ones safe.
965 : : *
966 : : * Also, lookup icq while holding queue_lock. If it doesn't exist,
967 : : * it will be created after releasing queue_lock.
968 : : */
969 [ + - ][ + - ]: 402828 : if (blk_rq_should_init_elevator(bio) && !blk_queue_bypass(q)) {
970 : 402828 : rw_flags |= REQ_ELVPRIV;
971 : 402828 : q->nr_rqs_elvpriv++;
972 [ + - ][ + - ]: 402828 : if (et->icq_cache && ioc)
973 : 402828 : icq = ioc_lookup_icq(ioc, q);
974 : : }
975 : :
976 [ + - ]: 402828 : if (blk_queue_io_stat(q))
977 : 402828 : rw_flags |= REQ_IO_STAT;
978 : 402828 : spin_unlock_irq(q->queue_lock);
979 : :
980 : : /* allocate and init request */
981 : 402828 : rq = mempool_alloc(rl->rq_pool, gfp_mask);
982 [ + - ]: 402828 : if (!rq)
983 : : goto fail_alloc;
984 : :
985 : 402828 : blk_rq_init(q, rq);
986 : : blk_rq_set_rl(rq, rl);
987 : 402821 : rq->cmd_flags = rw_flags | REQ_ALLOCED;
988 : :
989 : : /* init elvpriv */
990 [ + - ]: 402821 : if (rw_flags & REQ_ELVPRIV) {
991 [ + + ][ + + ]: 402821 : if (unlikely(et->icq_cache && !icq)) {
992 [ + - ]: 5269 : if (ioc)
993 : 5269 : icq = ioc_create_icq(ioc, q, gfp_mask);
994 [ + - ]: 5269 : if (!icq)
995 : : goto fail_elvpriv;
996 : : }
997 : :
998 : 402821 : rq->elv.icq = icq;
999 [ + - ]: 402821 : if (unlikely(elv_set_request(q, rq, bio, gfp_mask)))
1000 : : goto fail_elvpriv;
1001 : :
1002 : : /* @rq->elv.icq holds io_context until @rq is freed */
1003 [ + - ]: 402828 : if (icq)
1004 : 402828 : get_io_context(icq->ioc);
1005 : : }
1006 : : out:
1007 : : /*
1008 : : * ioc may be NULL here, and ioc_batching will be false. That's
1009 : : * OK, if the queue is under the request limit then requests need
1010 : : * not count toward the nr_batch_requests limit. There will always
1011 : : * be some limit enforced by BLK_BATCH_TIME.
1012 : : */
1013 [ + + ]: 806310 : if (ioc_batching(q, ioc))
1014 : 13614 : ioc->nr_batch_requests--;
1015 : :
1016 : 402732 : trace_block_getrq(q, bio, rw_flags & 1);
1017 : 402732 : return rq;
1018 : :
1019 : : fail_elvpriv:
1020 : : /*
1021 : : * elvpriv init failed. ioc, icq and elvpriv aren't mempool backed
1022 : : * and may fail indefinitely under memory pressure and thus
1023 : : * shouldn't stall IO. Treat this request as !elvpriv. This will
1024 : : * disturb iosched and blkcg but weird is bettern than dead.
1025 : : */
1026 [ # # ]: 0 : printk_ratelimited(KERN_WARNING "%s: request aux data allocation failed, iosched may be disturbed\n",
1027 : : dev_name(q->backing_dev_info.dev));
1028 : :
1029 : 0 : rq->cmd_flags &= ~REQ_ELVPRIV;
1030 : 0 : rq->elv.icq = NULL;
1031 : :
1032 : 0 : spin_lock_irq(q->queue_lock);
1033 : 0 : q->nr_rqs_elvpriv--;
1034 : 0 : spin_unlock_irq(q->queue_lock);
1035 : : goto out;
1036 : :
1037 : : fail_alloc:
1038 : : /*
1039 : : * Allocation failed presumably due to memory. Undo anything we
1040 : : * might have messed up.
1041 : : *
1042 : : * Allocating task should really be put onto the front of the wait
1043 : : * queue, but this is pretty rare.
1044 : : */
1045 : 0 : spin_lock_irq(q->queue_lock);
1046 : 0 : freed_request(rl, rw_flags);
1047 : :
1048 : : /*
1049 : : * in the very unlikely event that allocation failed and no
1050 : : * requests for this direction was pending, mark us starved so that
1051 : : * freeing of a request in the other direction will notice
1052 : : * us. another possible fix would be to split the rq mempool into
1053 : : * READ and WRITE
1054 : : */
1055 : : rq_starved:
1056 [ # # ]: 0 : if (unlikely(rl->count[is_sync] == 0))
1057 : 0 : rl->starved[is_sync] = 1;
1058 : : return NULL;
1059 : : }
1060 : :
1061 : : /**
1062 : : * get_request - get a free request
1063 : : * @q: request_queue to allocate request from
1064 : : * @rw_flags: RW and SYNC flags
1065 : : * @bio: bio to allocate request for (can be %NULL)
1066 : : * @gfp_mask: allocation mask
1067 : : *
1068 : : * Get a free request from @q. If %__GFP_WAIT is set in @gfp_mask, this
1069 : : * function keeps retrying under memory pressure and fails iff @q is dead.
1070 : : *
1071 : : * Must be callled with @q->queue_lock held and,
1072 : : * Returns %NULL on failure, with @q->queue_lock held.
1073 : : * Returns !%NULL on success, with @q->queue_lock *not held*.
1074 : : */
1075 : 0 : static struct request *get_request(struct request_queue *q, int rw_flags,
1076 : : struct bio *bio, gfp_t gfp_mask)
1077 : : {
1078 : 402828 : const bool is_sync = rw_is_sync(rw_flags) != 0;
1079 : 805656 : DEFINE_WAIT(wait);
1080 : : struct request_list *rl;
1081 : : struct request *rq;
1082 : :
1083 : 402828 : rl = blk_get_rl(q, bio); /* transferred to @rq on success */
1084 : : retry:
1085 : 403578 : rq = __get_request(rl, rw_flags, bio, gfp_mask);
1086 [ + + ]: 403431 : if (rq)
1087 : : return rq;
1088 : :
1089 [ + - ][ + - ]: 750 : if (!(gfp_mask & __GFP_WAIT) || unlikely(blk_queue_dying(q))) {
1090 : : blk_put_rl(rl);
1091 : : return NULL;
1092 : : }
1093 : :
1094 : : /* wait on @rl and retry */
1095 : 750 : prepare_to_wait_exclusive(&rl->wait[is_sync], &wait,
1096 : : TASK_UNINTERRUPTIBLE);
1097 : :
1098 : 750 : trace_block_sleeprq(q, bio, rw_flags & 1);
1099 : :
1100 : 0 : spin_unlock_irq(q->queue_lock);
1101 : 750 : io_schedule();
1102 : :
1103 : : /*
1104 : : * After sleeping, we become a "batching" process and will be able
1105 : : * to allocate at least one request, and up to a big batch of them
1106 : : * for a small period time. See ioc_batching, ioc_set_batching
1107 : : */
1108 : 750 : ioc_set_batching(q, current->io_context);
1109 : :
1110 : 750 : spin_lock_irq(q->queue_lock);
1111 : 750 : finish_wait(&rl->wait[is_sync], &wait);
1112 : :
1113 : 750 : goto retry;
1114 : : }
1115 : :
1116 : 0 : static struct request *blk_old_get_request(struct request_queue *q, int rw,
1117 : : gfp_t gfp_mask)
1118 : : {
1119 : : struct request *rq;
1120 : :
1121 [ - + ]: 14876 : BUG_ON(rw != READ && rw != WRITE);
1122 : :
1123 : : /* create ioc upfront */
1124 : 14876 : create_io_context(gfp_mask, q->node);
1125 : :
1126 : 14876 : spin_lock_irq(q->queue_lock);
1127 : 14876 : rq = get_request(q, rw, NULL, gfp_mask);
1128 [ - + ]: 14876 : if (!rq)
1129 : 0 : spin_unlock_irq(q->queue_lock);
1130 : : /* q->queue_lock is unlocked at this point */
1131 : :
1132 : 14876 : return rq;
1133 : : }
1134 : :
1135 : 0 : struct request *blk_get_request(struct request_queue *q, int rw, gfp_t gfp_mask)
1136 : : {
1137 [ - + ]: 14876 : if (q->mq_ops)
1138 : 0 : return blk_mq_alloc_request(q, rw, gfp_mask);
1139 : : else
1140 : 14876 : return blk_old_get_request(q, rw, gfp_mask);
1141 : : }
1142 : : EXPORT_SYMBOL(blk_get_request);
1143 : :
1144 : : /**
1145 : : * blk_make_request - given a bio, allocate a corresponding struct request.
1146 : : * @q: target request queue
1147 : : * @bio: The bio describing the memory mappings that will be submitted for IO.
1148 : : * It may be a chained-bio properly constructed by block/bio layer.
1149 : : * @gfp_mask: gfp flags to be used for memory allocation
1150 : : *
1151 : : * blk_make_request is the parallel of generic_make_request for BLOCK_PC
1152 : : * type commands. Where the struct request needs to be farther initialized by
1153 : : * the caller. It is passed a &struct bio, which describes the memory info of
1154 : : * the I/O transfer.
1155 : : *
1156 : : * The caller of blk_make_request must make sure that bi_io_vec
1157 : : * are set to describe the memory buffers. That bio_data_dir() will return
1158 : : * the needed direction of the request. (And all bio's in the passed bio-chain
1159 : : * are properly set accordingly)
1160 : : *
1161 : : * If called under none-sleepable conditions, mapped bio buffers must not
1162 : : * need bouncing, by calling the appropriate masked or flagged allocator,
1163 : : * suitable for the target device. Otherwise the call to blk_queue_bounce will
1164 : : * BUG.
1165 : : *
1166 : : * WARNING: When allocating/cloning a bio-chain, careful consideration should be
1167 : : * given to how you allocate bios. In particular, you cannot use __GFP_WAIT for
1168 : : * anything but the first bio in the chain. Otherwise you risk waiting for IO
1169 : : * completion of a bio that hasn't been submitted yet, thus resulting in a
1170 : : * deadlock. Alternatively bios should be allocated using bio_kmalloc() instead
1171 : : * of bio_alloc(), as that avoids the mempool deadlock.
1172 : : * If possible a big IO should be split into smaller parts when allocation
1173 : : * fails. Partial allocation should not be an error, or you risk a live-lock.
1174 : : */
1175 : 0 : struct request *blk_make_request(struct request_queue *q, struct bio *bio,
1176 : : gfp_t gfp_mask)
1177 : : {
1178 : 0 : struct request *rq = blk_get_request(q, bio_data_dir(bio), gfp_mask);
1179 : :
1180 [ # # ]: 0 : if (unlikely(!rq))
1181 : : return ERR_PTR(-ENOMEM);
1182 : :
1183 [ # # ]: 0 : for_each_bio(bio) {
1184 : 0 : struct bio *bounce_bio = bio;
1185 : : int ret;
1186 : :
1187 : 0 : blk_queue_bounce(q, &bounce_bio);
1188 : 0 : ret = blk_rq_append_bio(q, rq, bounce_bio);
1189 [ # # ]: 0 : if (unlikely(ret)) {
1190 : 0 : blk_put_request(rq);
1191 : 0 : return ERR_PTR(ret);
1192 : : }
1193 : : }
1194 : :
1195 : : return rq;
1196 : : }
1197 : : EXPORT_SYMBOL(blk_make_request);
1198 : :
1199 : : /**
1200 : : * blk_requeue_request - put a request back on queue
1201 : : * @q: request queue where request should be inserted
1202 : : * @rq: request to be inserted
1203 : : *
1204 : : * Description:
1205 : : * Drivers often keep queueing requests until the hardware cannot accept
1206 : : * more, when that condition happens we need to put the request back
1207 : : * on the queue. Must be called with queue lock held.
1208 : : */
1209 : 0 : void blk_requeue_request(struct request_queue *q, struct request *rq)
1210 : : {
1211 : 0 : blk_delete_timer(rq);
1212 : : blk_clear_rq_complete(rq);
1213 : : trace_block_rq_requeue(q, rq);
1214 : :
1215 [ # # ]: 0 : if (blk_rq_tagged(rq))
1216 : 0 : blk_queue_end_tag(q, rq);
1217 : :
1218 [ # # ]: 0 : BUG_ON(blk_queued_rq(rq));
1219 : :
1220 : 0 : elv_requeue_request(q, rq);
1221 : 0 : }
1222 : : EXPORT_SYMBOL(blk_requeue_request);
1223 : :
1224 : : static void add_acct_request(struct request_queue *q, struct request *rq,
1225 : : int where)
1226 : : {
1227 : 20620 : blk_account_io_start(rq, true);
1228 : 20620 : __elv_add_request(q, rq, where);
1229 : : }
1230 : :
1231 : 0 : static void part_round_stats_single(int cpu, struct hd_struct *part,
1232 : : unsigned long now)
1233 : : {
1234 [ + ]: 1551681 : if (now == part->stamp)
1235 : 0 : return;
1236 : :
1237 [ + + ]: 1970686 : if (part_in_flight(part)) {
1238 : 676004 : __part_stat_add(cpu, part, time_in_queue,
1239 : : part_in_flight(part) * (now - part->stamp));
1240 : 338002 : __part_stat_add(cpu, part, io_ticks, (now - part->stamp));
1241 : : }
1242 : 419005 : part->stamp = now;
1243 : : }
1244 : :
1245 : : /**
1246 : : * part_round_stats() - Round off the performance stats on a struct disk_stats.
1247 : : * @cpu: cpu number for stats access
1248 : : * @part: target partition
1249 : : *
1250 : : * The average IO queue length and utilisation statistics are maintained
1251 : : * by observing the current state of the queue length and the amount of
1252 : : * time it has been in this state for.
1253 : : *
1254 : : * Normally, that accounting is done on IO completion, but that can result
1255 : : * in more than a second's worth of IO being accounted for within any one
1256 : : * second, leading to >100% utilisation. To deal with that, we call this
1257 : : * function to do a round-off before returning the results when reading
1258 : : * /proc/diskstats. This accounts immediately for all queue usage up to
1259 : : * the current jiffies and restarts the counters again.
1260 : : */
1261 : 0 : void part_round_stats(int cpu, struct hd_struct *part)
1262 : : {
1263 : 775921 : unsigned long now = jiffies;
1264 : :
1265 [ + + ]: 775921 : if (part->partno)
1266 : 775899 : part_round_stats_single(cpu, &part_to_disk(part)->part0, now);
1267 : 775896 : part_round_stats_single(cpu, part, now);
1268 : 775910 : }
1269 : : EXPORT_SYMBOL_GPL(part_round_stats);
1270 : :
1271 : : #ifdef CONFIG_PM_RUNTIME
1272 : : static void blk_pm_put_request(struct request *rq)
1273 : : {
1274 : : if (rq->q->dev && !(rq->cmd_flags & REQ_PM) && !--rq->q->nr_pending)
1275 : : pm_runtime_mark_last_busy(rq->q->dev);
1276 : : }
1277 : : #else
1278 : : static inline void blk_pm_put_request(struct request *rq) {}
1279 : : #endif
1280 : :
1281 : : /*
1282 : : * queue lock must be held
1283 : : */
1284 : 0 : void __blk_put_request(struct request_queue *q, struct request *req)
1285 : : {
1286 [ + - ]: 402828 : if (unlikely(!q))
1287 : : return;
1288 : :
1289 [ - + ]: 402828 : if (q->mq_ops) {
1290 : 0 : blk_mq_free_request(req);
1291 : 0 : return;
1292 : : }
1293 : :
1294 : : blk_pm_put_request(req);
1295 : :
1296 : 402828 : elv_completed_request(q, req);
1297 : :
1298 : : /* this is a bio leak */
1299 [ - + ]: 402828 : WARN_ON(req->bio != NULL);
1300 : :
1301 : : /*
1302 : : * Request may not have originated from ll_rw_blk. if not,
1303 : : * it didn't come out of our reserved rq pools
1304 : : */
1305 [ + - ]: 805656 : if (req->cmd_flags & REQ_ALLOCED) {
1306 : 402828 : unsigned int flags = req->cmd_flags;
1307 : 805656 : struct request_list *rl = blk_rq_rl(req);
1308 : :
1309 [ - + ]: 402828 : BUG_ON(!list_empty(&req->queuelist));
1310 [ - + ]: 402828 : BUG_ON(!hlist_unhashed(&req->hash));
1311 : :
1312 : : blk_free_request(rl, req);
1313 : 402828 : freed_request(rl, flags);
1314 : : blk_put_rl(rl);
1315 : : }
1316 : : }
1317 : : EXPORT_SYMBOL_GPL(__blk_put_request);
1318 : :
1319 : 0 : void blk_put_request(struct request *req)
1320 : : {
1321 : 14876 : struct request_queue *q = req->q;
1322 : :
1323 [ - + ]: 14876 : if (q->mq_ops)
1324 : 0 : blk_mq_free_request(req);
1325 : : else {
1326 : : unsigned long flags;
1327 : :
1328 : 14876 : spin_lock_irqsave(q->queue_lock, flags);
1329 : 14876 : __blk_put_request(q, req);
1330 : 14876 : spin_unlock_irqrestore(q->queue_lock, flags);
1331 : : }
1332 : 14876 : }
1333 : : EXPORT_SYMBOL(blk_put_request);
1334 : :
1335 : : /**
1336 : : * blk_add_request_payload - add a payload to a request
1337 : : * @rq: request to update
1338 : : * @page: page backing the payload
1339 : : * @len: length of the payload.
1340 : : *
1341 : : * This allows to later add a payload to an already submitted request by
1342 : : * a block driver. The driver needs to take care of freeing the payload
1343 : : * itself.
1344 : : *
1345 : : * Note that this is a quite horrible hack and nothing but handling of
1346 : : * discard requests should ever use it.
1347 : : */
1348 : 0 : void blk_add_request_payload(struct request *rq, struct page *page,
1349 : : unsigned int len)
1350 : : {
1351 : 0 : struct bio *bio = rq->bio;
1352 : :
1353 : 0 : bio->bi_io_vec->bv_page = page;
1354 : 0 : bio->bi_io_vec->bv_offset = 0;
1355 : 0 : bio->bi_io_vec->bv_len = len;
1356 : :
1357 : 0 : bio->bi_iter.bi_size = len;
1358 : 0 : bio->bi_vcnt = 1;
1359 : 0 : bio->bi_phys_segments = 1;
1360 : :
1361 : 0 : rq->__data_len = rq->resid_len = len;
1362 : 0 : rq->nr_phys_segments = 1;
1363 : 0 : rq->buffer = bio_data(bio);
1364 : 0 : }
1365 : : EXPORT_SYMBOL_GPL(blk_add_request_payload);
1366 : :
1367 : 0 : bool bio_attempt_back_merge(struct request_queue *q, struct request *req,
1368 : : struct bio *bio)
1369 : : {
1370 : 87125 : const int ff = bio->bi_rw & REQ_FAILFAST_MASK;
1371 : :
1372 [ + + ]: 87125 : if (!ll_back_merge_fn(q, req, bio))
1373 : : return false;
1374 : :
1375 : : trace_block_bio_backmerge(q, req, bio);
1376 : :
1377 [ + + ]: 65748 : if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff)
1378 : 5270 : blk_rq_set_mixed_merge(req);
1379 : :
1380 : 65748 : req->biotail->bi_next = bio;
1381 : 65748 : req->biotail = bio;
1382 : 65748 : req->__data_len += bio->bi_iter.bi_size;
1383 : 65748 : req->ioprio = ioprio_best(req->ioprio, bio_prio(bio));
1384 : :
1385 : 65747 : blk_account_io_start(req, false);
1386 : 65747 : return true;
1387 : : }
1388 : :
1389 : 0 : bool bio_attempt_front_merge(struct request_queue *q, struct request *req,
1390 : : struct bio *bio)
1391 : : {
1392 : 1237 : const int ff = bio->bi_rw & REQ_FAILFAST_MASK;
1393 : :
1394 [ + + ]: 1237 : if (!ll_front_merge_fn(q, req, bio))
1395 : : return false;
1396 : :
1397 : : trace_block_bio_frontmerge(q, req, bio);
1398 : :
1399 [ + + ]: 2454 : if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff)
1400 : 144 : blk_rq_set_mixed_merge(req);
1401 : :
1402 : 1217 : bio->bi_next = req->bio;
1403 : 1217 : req->bio = bio;
1404 : :
1405 : : /*
1406 : : * may not be valid. if the low level driver said
1407 : : * it didn't need a bounce buffer then it better
1408 : : * not touch req->buffer either...
1409 : : */
1410 : 1217 : req->buffer = bio_data(bio);
1411 : 1217 : req->__sector = bio->bi_iter.bi_sector;
1412 : 1217 : req->__data_len += bio->bi_iter.bi_size;
1413 : 1217 : req->ioprio = ioprio_best(req->ioprio, bio_prio(bio));
1414 : :
1415 : 1217 : blk_account_io_start(req, false);
1416 : 1217 : return true;
1417 : : }
1418 : :
1419 : : /**
1420 : : * blk_attempt_plug_merge - try to merge with %current's plugged list
1421 : : * @q: request_queue new bio is being queued at
1422 : : * @bio: new bio being queued
1423 : : * @request_count: out parameter for number of traversed plugged requests
1424 : : *
1425 : : * Determine whether @bio being queued on @q can be merged with a request
1426 : : * on %current's plugged list. Returns %true if merge was successful,
1427 : : * otherwise %false.
1428 : : *
1429 : : * Plugging coalesces IOs from the same issuer for the same purpose without
1430 : : * going through @q->queue_lock. As such it's more of an issuing mechanism
1431 : : * than scheduling, and the request, while may have elvpriv data, is not
1432 : : * added on the elevator at this point. In addition, we don't have
1433 : : * reliable access to the elevator outside queue lock. Only check basic
1434 : : * merging parameters without querying the elevator.
1435 : : */
1436 : 0 : bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
1437 : : unsigned int *request_count)
1438 : : {
1439 : : struct blk_plug *plug;
1440 : : struct request *rq;
1441 : : bool ret = false;
1442 : : struct list_head *plug_list;
1443 : :
1444 [ + + ]: 454908 : if (blk_queue_nomerges(q))
1445 : : goto out;
1446 : :
1447 : 454903 : plug = current->plug;
1448 [ + + ]: 454903 : if (!plug)
1449 : : goto out;
1450 : 428871 : *request_count = 0;
1451 : :
1452 [ + + ]: 428871 : if (q->mq_ops)
1453 : 2 : plug_list = &plug->mq_list;
1454 : : else
1455 : 428869 : plug_list = &plug->list;
1456 : :
1457 [ + + ]: 1275991 : list_for_each_entry_reverse(rq, plug_list, queuelist) {
1458 : : int el_ret;
1459 : :
1460 [ + + ]: 901567 : if (rq->q == q)
1461 : 901474 : (*request_count)++;
1462 : :
1463 [ + + ][ + + ]: 901567 : if (rq->q != q || !blk_rq_merge_ok(rq, bio))
1464 : 91738 : continue;
1465 : :
1466 : 809959 : el_ret = blk_try_merge(rq, bio);
1467 [ + + ]: 809916 : if (el_ret == ELEVATOR_BACK_MERGE) {
1468 : 74731 : ret = bio_attempt_back_merge(q, rq, bio);
1469 [ + + ]: 74731 : if (ret)
1470 : : break;
1471 [ + + ]: 735185 : } else if (el_ret == ELEVATOR_FRONT_MERGE) {
1472 : 36 : ret = bio_attempt_front_merge(q, rq, bio);
1473 [ - + ]: 36 : if (ret)
1474 : : break;
1475 : : }
1476 : : }
1477 : : out:
1478 : 87 : return ret;
1479 : : }
1480 : :
1481 : 0 : void init_request_from_bio(struct request *req, struct bio *bio)
1482 : : {
1483 : 387891 : req->cmd_type = REQ_TYPE_FS;
1484 : :
1485 : 387891 : req->cmd_flags |= bio->bi_rw & REQ_COMMON_MASK;
1486 [ + + ]: 387891 : if (bio->bi_rw & REQ_RAHEAD)
1487 : 734 : req->cmd_flags |= REQ_FAILFAST_MASK;
1488 : :
1489 : 0 : req->errors = 0;
1490 : 0 : req->__sector = bio->bi_iter.bi_sector;
1491 : 0 : req->ioprio = bio_prio(bio);
1492 : 387891 : blk_rq_bio_prep(req->q, req, bio);
1493 : 387926 : }
1494 : :
1495 : 0 : void blk_queue_bio(struct request_queue *q, struct bio *bio)
1496 : : {
1497 : 454870 : const bool sync = !!(bio->bi_rw & REQ_SYNC);
1498 : : struct blk_plug *plug;
1499 : : int el_ret, rw_flags, where = ELEVATOR_INSERT_SORT;
1500 : : struct request *req;
1501 : 454870 : unsigned int request_count = 0;
1502 : :
1503 : : /*
1504 : : * low level driver can indicate that it wants pages above a
1505 : : * certain limit bounced to low memory (ie for highmem, or even
1506 : : * ISA dma in theory)
1507 : : */
1508 : 454870 : blk_queue_bounce(q, &bio);
1509 : :
1510 : : if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) {
1511 : : bio_endio(bio, -EIO);
1512 : 54461 : return;
1513 : : }
1514 : :
1515 [ - + ]: 454902 : if (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) {
1516 : 0 : spin_lock_irq(q->queue_lock);
1517 : : where = ELEVATOR_INSERT_FLUSH;
1518 : 0 : goto get_rq;
1519 : : }
1520 : :
1521 : : /*
1522 : : * Check if we can merge with the plugged list before grabbing
1523 : : * any locks.
1524 : : */
1525 [ + + ]: 454902 : if (blk_attempt_plug_merge(q, bio, &request_count))
1526 : : return;
1527 : :
1528 : 400441 : spin_lock_irq(q->queue_lock);
1529 : :
1530 : 400456 : el_ret = elv_merge(q, &req, bio);
1531 [ + + ]: 400456 : if (el_ret == ELEVATOR_BACK_MERGE) {
1532 [ + + ]: 12394 : if (bio_attempt_back_merge(q, req, bio)) {
1533 : 11323 : elv_bio_merged(q, req, bio);
1534 [ + + ]: 11323 : if (!attempt_back_merge(q, req))
1535 : 11204 : elv_merged_request(q, req, el_ret);
1536 : : goto out_unlock;
1537 : : }
1538 [ + + ]: 388062 : } else if (el_ret == ELEVATOR_FRONT_MERGE) {
1539 [ + + ]: 1201 : if (bio_attempt_front_merge(q, req, bio)) {
1540 : 1181 : elv_bio_merged(q, req, bio);
1541 [ + + ]: 1181 : if (!attempt_front_merge(q, req))
1542 : 1078 : elv_merged_request(q, req, el_ret);
1543 : : goto out_unlock;
1544 : : }
1545 : : }
1546 : :
1547 : : get_rq:
1548 : : /*
1549 : : * This sync check and mask will be re-done in init_request_from_bio(),
1550 : : * but we need to set it earlier to expose the sync flag to the
1551 : : * rq allocator and io schedulers.
1552 : : */
1553 : 387952 : rw_flags = bio_data_dir(bio);
1554 [ + + ]: 387952 : if (sync)
1555 : 256424 : rw_flags |= REQ_SYNC;
1556 : :
1557 : : /*
1558 : : * Grab a free request. This is might sleep but can not fail.
1559 : : * Returns with the queue unlocked.
1560 : : */
1561 : 387952 : req = get_request(q, rw_flags, bio, GFP_NOIO);
1562 [ - + ]: 387863 : if (unlikely(!req)) {
1563 : 0 : bio_endio(bio, -ENODEV); /* @q is dead */
1564 : 0 : goto out_unlock;
1565 : : }
1566 : :
1567 : : /*
1568 : : * After dropping the lock and possibly sleeping here, our request
1569 : : * may now be mergeable after it had proven unmergeable (above).
1570 : : * We don't worry about that case for efficiency. It won't happen
1571 : : * often, and the elevators are able to handle it.
1572 : : */
1573 : 387863 : init_request_from_bio(req, bio);
1574 : :
1575 [ + + ]: 387926 : if (test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags))
1576 : 387920 : req->cpu = raw_smp_processor_id();
1577 : :
1578 : 387926 : plug = current->plug;
1579 [ + + ]: 387926 : if (plug) {
1580 : : /*
1581 : : * If this is the first request added after a plug, fire
1582 : : * of a plug trace.
1583 : : */
1584 [ + + ]: 367306 : if (!request_count)
1585 : : trace_block_plug(q);
1586 : : else {
1587 [ + + ]: 136881 : if (request_count >= BLK_MAX_REQUEST_COUNT) {
1588 : 3315 : blk_flush_plug_list(plug, false);
1589 : : trace_block_plug(q);
1590 : : }
1591 : : }
1592 : 367306 : list_add_tail(&req->queuelist, &plug->list);
1593 : 367306 : blk_account_io_start(req, true);
1594 : : } else {
1595 : 20620 : spin_lock_irq(q->queue_lock);
1596 : 20620 : add_acct_request(q, req, where);
1597 : 20620 : __blk_run_queue(q);
1598 : : out_unlock:
1599 : 33124 : spin_unlock_irq(q->queue_lock);
1600 : : }
1601 : : }
1602 : : EXPORT_SYMBOL_GPL(blk_queue_bio); /* for device mapper only */
1603 : :
1604 : : /*
1605 : : * If bio->bi_dev is a partition, remap the location
1606 : : */
1607 : : static inline void blk_partition_remap(struct bio *bio)
1608 : : {
1609 : : struct block_device *bdev = bio->bi_bdev;
1610 : :
1611 [ + + ][ + + ]: 463189 : if (bio_sectors(bio) && bdev != bdev->bd_contains) {
1612 : : struct hd_struct *p = bdev->bd_part;
1613 : :
1614 : 454895 : bio->bi_iter.bi_sector += p->start_sect;
1615 : 454895 : bio->bi_bdev = bdev->bd_contains;
1616 : :
1617 : 1364685 : trace_block_bio_remap(bdev_get_queue(bio->bi_bdev), bio,
1618 : : bdev->bd_dev,
1619 : 454895 : bio->bi_iter.bi_sector - p->start_sect);
1620 : : }
1621 : : }
1622 : :
1623 : 0 : static void handle_bad_sector(struct bio *bio)
1624 : : {
1625 : : char b[BDEVNAME_SIZE];
1626 : :
1627 : 0 : printk(KERN_INFO "attempt to access beyond end of device\n");
1628 : 0 : printk(KERN_INFO "%s: rw=%ld, want=%Lu, limit=%Lu\n",
1629 : : bdevname(bio->bi_bdev, b),
1630 : : bio->bi_rw,
1631 : 0 : (unsigned long long)bio_end_sector(bio),
1632 : 0 : (long long)(i_size_read(bio->bi_bdev->bd_inode) >> 9));
1633 : :
1634 : 0 : set_bit(BIO_EOF, &bio->bi_flags);
1635 : 0 : }
1636 : :
1637 : : #ifdef CONFIG_FAIL_MAKE_REQUEST
1638 : :
1639 : : static DECLARE_FAULT_ATTR(fail_make_request);
1640 : :
1641 : : static int __init setup_fail_make_request(char *str)
1642 : : {
1643 : : return setup_fault_attr(&fail_make_request, str);
1644 : : }
1645 : : __setup("fail_make_request=", setup_fail_make_request);
1646 : :
1647 : : static bool should_fail_request(struct hd_struct *part, unsigned int bytes)
1648 : : {
1649 : : return part->make_it_fail && should_fail(&fail_make_request, bytes);
1650 : : }
1651 : :
1652 : : static int __init fail_make_request_debugfs(void)
1653 : : {
1654 : : struct dentry *dir = fault_create_debugfs_attr("fail_make_request",
1655 : : NULL, &fail_make_request);
1656 : :
1657 : : return IS_ERR(dir) ? PTR_ERR(dir) : 0;
1658 : : }
1659 : :
1660 : : late_initcall(fail_make_request_debugfs);
1661 : :
1662 : : #else /* CONFIG_FAIL_MAKE_REQUEST */
1663 : :
1664 : : static inline bool should_fail_request(struct hd_struct *part,
1665 : : unsigned int bytes)
1666 : : {
1667 : : return false;
1668 : : }
1669 : :
1670 : : #endif /* CONFIG_FAIL_MAKE_REQUEST */
1671 : :
1672 : : /*
1673 : : * Check whether this bio extends beyond the end of the device.
1674 : : */
1675 : : static inline int bio_check_eod(struct bio *bio, unsigned int nr_sectors)
1676 : : {
1677 : : sector_t maxsector;
1678 : :
1679 [ + + ][ + + ]: 926363 : if (!nr_sectors)
1680 : : return 0;
1681 : :
1682 : : /* Test device or partition size, when known. */
1683 : 922246 : maxsector = i_size_read(bio->bi_bdev->bd_inode) >> 9;
1684 [ + ][ + ]: 922225 : if (maxsector) {
1685 : 922229 : sector_t sector = bio->bi_iter.bi_sector;
1686 : :
1687 [ + ][ + ][ + ]: 922229 : if (maxsector < nr_sectors || maxsector - nr_sectors < sector) {
[ + ]
1688 : : /*
1689 : : * This may well happen - the kernel calls bread()
1690 : : * without checking the size of the device, e.g., when
1691 : : * mounting a device.
1692 : : */
1693 : 0 : handle_bad_sector(bio);
1694 : : return 1;
1695 : : }
1696 : : }
1697 : :
1698 : : return 0;
1699 : : }
1700 : :
1701 : : static noinline_for_stack bool
1702 : 0 : generic_make_request_checks(struct bio *bio)
1703 : : {
1704 : 461104 : struct request_queue *q;
1705 : 463201 : int nr_sectors = bio_sectors(bio);
1706 : : int err = -EIO;
1707 : : char b[BDEVNAME_SIZE];
1708 : : struct hd_struct *part;
1709 : :
1710 : : might_sleep();
1711 : :
1712 [ + - ]: 463189 : if (bio_check_eod(bio, nr_sectors))
1713 : : goto end_io;
1714 : :
1715 : 463189 : q = bdev_get_queue(bio->bi_bdev);
1716 [ - + ]: 463189 : if (unlikely(!q)) {
1717 : 0 : printk(KERN_ERR
1718 : : "generic_make_request: Trying to access "
1719 : : "nonexistent block-device %s (%Lu)\n",
1720 : : bdevname(bio->bi_bdev, b),
1721 : 0 : (long long) bio->bi_iter.bi_sector);
1722 : 0 : goto end_io;
1723 : : }
1724 : :
1725 [ + + ][ - + ]: 463189 : if (likely(bio_is_rw(bio) &&
1726 : : nr_sectors > queue_max_hw_sectors(q))) {
1727 : 0 : printk(KERN_ERR "bio too big device %s (%u > %u)\n",
1728 : : bdevname(bio->bi_bdev, b),
1729 : 0 : bio_sectors(bio),
1730 : : queue_max_hw_sectors(q));
1731 : 0 : goto end_io;
1732 : : }
1733 : :
1734 : 463189 : part = bio->bi_bdev->bd_part;
1735 : : if (should_fail_request(part, bio->bi_iter.bi_size) ||
1736 : : should_fail_request(&part_to_disk(part)->part0,
1737 : : bio->bi_iter.bi_size))
1738 : : goto end_io;
1739 : :
1740 : : /*
1741 : : * If this device has partitions, remap block n
1742 : : * of partition p to block n+start(p) of the disk.
1743 : : */
1744 : : blk_partition_remap(bio);
1745 : :
1746 [ + - ]: 463191 : if (bio_check_eod(bio, nr_sectors))
1747 : : goto end_io;
1748 : :
1749 : : /*
1750 : : * Filter flush bio's early so that make_request based
1751 : : * drivers without flush support don't have to worry
1752 : : * about them.
1753 : : */
1754 [ + + ][ + + ]: 463191 : if ((bio->bi_rw & (REQ_FLUSH | REQ_FUA)) && !q->flush_flags) {
1755 : 21066 : bio->bi_rw &= ~(REQ_FLUSH | REQ_FUA);
1756 [ + + ]: 21066 : if (!nr_sectors) {
1757 : : err = 0;
1758 : : goto end_io;
1759 : : }
1760 : : }
1761 : :
1762 [ + + ][ + - ]: 461163 : if ((bio->bi_rw & REQ_DISCARD) &&
1763 [ - + ]: 34 : (!blk_queue_discard(q) ||
1764 [ # # ][ # # ]: 0 : ((bio->bi_rw & REQ_SECURE) && !blk_queue_secdiscard(q)))) {
1765 : : err = -EOPNOTSUPP;
1766 : : goto end_io;
1767 : : }
1768 : :
1769 [ - + ][ # # ]: 461163 : if (bio->bi_rw & REQ_WRITE_SAME && !bdev_write_same(bio->bi_bdev)) {
1770 : : err = -EOPNOTSUPP;
1771 : : goto end_io;
1772 : : }
1773 : :
1774 : : /*
1775 : : * Various block parts want %current->io_context and lazy ioc
1776 : : * allocation ends up trading a lot of pain for a small amount of
1777 : : * memory. Just allocate it upfront. This may fail and block
1778 : : * layer knows how to live with it.
1779 : : */
1780 : 461163 : create_io_context(GFP_ATOMIC, q->node);
1781 : :
1782 : : if (blk_throtl_bio(q, bio))
1783 : : return false; /* throttled, will be resubmitted later */
1784 : :
1785 : : trace_block_bio_queue(q, bio);
1786 : : return true;
1787 : :
1788 : : end_io:
1789 : 2028 : bio_endio(bio, err);
1790 : 2030 : return false;
1791 : : }
1792 : :
1793 : : /**
1794 : : * generic_make_request - hand a buffer to its device driver for I/O
1795 : : * @bio: The bio describing the location in memory and on the device.
1796 : : *
1797 : : * generic_make_request() is used to make I/O requests of block
1798 : : * devices. It is passed a &struct bio, which describes the I/O that needs
1799 : : * to be done.
1800 : : *
1801 : : * generic_make_request() does not return any status. The
1802 : : * success/failure status of the request, along with notification of
1803 : : * completion, is delivered asynchronously through the bio->bi_end_io
1804 : : * function described (one day) else where.
1805 : : *
1806 : : * The caller of generic_make_request must make sure that bi_io_vec
1807 : : * are set to describe the memory buffer, and that bi_dev and bi_sector are
1808 : : * set to describe the device address, and the
1809 : : * bi_end_io and optionally bi_private are set to describe how
1810 : : * completion notification should be signaled.
1811 : : *
1812 : : * generic_make_request and the drivers it calls may use bi_next if this
1813 : : * bio happens to be merged with someone else, and may resubmit the bio to
1814 : : * a lower device by calling into generic_make_request recursively, which
1815 : : * means the bio should NOT be touched after the call to ->make_request_fn.
1816 : : */
1817 : 0 : void generic_make_request(struct bio *bio)
1818 : : {
1819 : : struct bio_list bio_list_on_stack;
1820 : :
1821 [ + + ]: 463206 : if (!generic_make_request_checks(bio))
1822 : 2025 : return;
1823 : :
1824 : : /*
1825 : : * We only want one ->make_request_fn to be active at a time, else
1826 : : * stack usage with stacked devices could be a problem. So use
1827 : : * current->bio_list to keep a list of requests submited by a
1828 : : * make_request_fn function. current->bio_list is also used as a
1829 : : * flag to say if generic_make_request is currently active in this
1830 : : * task or not. If it is NULL, then no make_request is active. If
1831 : : * it is non-NULL, then a make_request is active, and new requests
1832 : : * should be added at the tail
1833 : : */
1834 [ - + ]: 461175 : if (current->bio_list) {
1835 : : bio_list_add(current->bio_list, bio);
1836 : : return;
1837 : : }
1838 : :
1839 : : /* following loop may be a bit non-obvious, and so deserves some
1840 : : * explanation.
1841 : : * Before entering the loop, bio->bi_next is NULL (as all callers
1842 : : * ensure that) so we have a list with a single bio.
1843 : : * We pretend that we have just taken it off a longer list, so
1844 : : * we assign bio_list to a pointer to the bio_list_on_stack,
1845 : : * thus initialising the bio_list of new bios to be
1846 : : * added. ->make_request() may indeed add some more bios
1847 : : * through a recursive call to generic_make_request. If it
1848 : : * did, we find a non-NULL value in bio_list and re-enter the loop
1849 : : * from the top. In this case we really did just take the bio
1850 : : * of the top of the list (no pretending) and so remove it from
1851 : : * bio_list, and call into ->make_request() again.
1852 : : */
1853 [ - + ]: 461175 : BUG_ON(bio->bi_next);
1854 : : bio_list_init(&bio_list_on_stack);
1855 : 461175 : current->bio_list = &bio_list_on_stack;
1856 : : do {
1857 : 461139 : struct request_queue *q = bdev_get_queue(bio->bi_bdev);
1858 : :
1859 : 461139 : q->make_request_fn(q, bio);
1860 : :
1861 : 461134 : bio = bio_list_pop(current->bio_list);
1862 [ + ]: 461134 : } while (bio);
1863 : 461170 : current->bio_list = NULL; /* deactivate */
1864 : : }
1865 : : EXPORT_SYMBOL(generic_make_request);
1866 : :
1867 : : /**
1868 : : * submit_bio - submit a bio to the block device layer for I/O
1869 : : * @rw: whether to %READ or %WRITE, or maybe to %READA (read ahead)
1870 : : * @bio: The &struct bio which describes the I/O
1871 : : *
1872 : : * submit_bio() is very similar in purpose to generic_make_request(), and
1873 : : * uses that function to do most of the work. Both are fairly rough
1874 : : * interfaces; @bio must be presetup and ready for I/O.
1875 : : *
1876 : : */
1877 : 0 : void submit_bio(int rw, struct bio *bio)
1878 : : {
1879 : 463210 : bio->bi_rw |= rw;
1880 : :
1881 : : /*
1882 : : * If it's a regular read/write or a barrier with data attached,
1883 : : * go through the normal accounting stuff before submission.
1884 : : */
1885 [ + ]: 463210 : if (bio_has_data(bio)) {
1886 : : unsigned int count;
1887 : :
1888 [ + + ]: 924329 : if (unlikely(rw & REQ_WRITE_SAME))
1889 : 1 : count = bdev_logical_block_size(bio->bi_bdev) >> 9;
1890 : : else
1891 : 461118 : count = bio_sectors(bio);
1892 : :
1893 [ + + ]: 461119 : if (rw & WRITE) {
1894 : : count_vm_events(PGPGOUT, count);
1895 : : } else {
1896 : : task_io_account_read(bio->bi_iter.bi_size);
1897 : : count_vm_events(PGPGIN, count);
1898 : : }
1899 : :
1900 [ - + ]: 461118 : if (unlikely(block_dump)) {
1901 : : char b[BDEVNAME_SIZE];
1902 [ # # ]: 0 : printk(KERN_DEBUG "%s(%d): %s block %Lu on %s (%u sectors)\n",
1903 : 0 : current->comm, task_pid_nr(current),
1904 : : (rw & WRITE) ? "WRITE" : "READ",
1905 : : (unsigned long long)bio->bi_iter.bi_sector,
1906 : : bdevname(bio->bi_bdev, b),
1907 : : count);
1908 : : }
1909 : : }
1910 : :
1911 : 0 : generic_make_request(bio);
1912 : 463188 : }
1913 : : EXPORT_SYMBOL(submit_bio);
1914 : :
1915 : : /**
1916 : : * blk_rq_check_limits - Helper function to check a request for the queue limit
1917 : : * @q: the queue
1918 : : * @rq: the request being checked
1919 : : *
1920 : : * Description:
1921 : : * @rq may have been made based on weaker limitations of upper-level queues
1922 : : * in request stacking drivers, and it may violate the limitation of @q.
1923 : : * Since the block layer and the underlying device driver trust @rq
1924 : : * after it is inserted to @q, it should be checked against @q before
1925 : : * the insertion using this generic function.
1926 : : *
1927 : : * This function should also be useful for request stacking drivers
1928 : : * in some cases below, so export this function.
1929 : : * Request stacking drivers like request-based dm may change the queue
1930 : : * limits while requests are in the queue (e.g. dm's table swapping).
1931 : : * Such request stacking drivers should check those requests agaist
1932 : : * the new queue limits again when they dispatch those requests,
1933 : : * although such checkings are also done against the old queue limits
1934 : : * when submitting requests.
1935 : : */
1936 : 0 : int blk_rq_check_limits(struct request_queue *q, struct request *rq)
1937 : : {
1938 [ # # ]: 0 : if (!rq_mergeable(rq))
1939 : : return 0;
1940 : :
1941 [ # # ]: 0 : if (blk_rq_sectors(rq) > blk_queue_get_max_sectors(q, rq->cmd_flags)) {
1942 : 0 : printk(KERN_ERR "%s: over max size limit.\n", __func__);
1943 : 0 : return -EIO;
1944 : : }
1945 : :
1946 : : /*
1947 : : * queue's settings related to segment counting like q->bounce_pfn
1948 : : * may differ from that of other stacking queues.
1949 : : * Recalculate it to check the request correctly on this queue's
1950 : : * limitation.
1951 : : */
1952 : 0 : blk_recalc_rq_segments(rq);
1953 [ # # ]: 0 : if (rq->nr_phys_segments > queue_max_segments(q)) {
1954 : 0 : printk(KERN_ERR "%s: over max segments limit.\n", __func__);
1955 : 0 : return -EIO;
1956 : : }
1957 : :
1958 : : return 0;
1959 : : }
1960 : : EXPORT_SYMBOL_GPL(blk_rq_check_limits);
1961 : :
1962 : : /**
1963 : : * blk_insert_cloned_request - Helper for stacking drivers to submit a request
1964 : : * @q: the queue to submit the request
1965 : : * @rq: the request being queued
1966 : : */
1967 : 0 : int blk_insert_cloned_request(struct request_queue *q, struct request *rq)
1968 : : {
1969 : : unsigned long flags;
1970 : : int where = ELEVATOR_INSERT_BACK;
1971 : :
1972 [ # # ]: 0 : if (blk_rq_check_limits(q, rq))
1973 : : return -EIO;
1974 : :
1975 : : if (rq->rq_disk &&
1976 : : should_fail_request(&rq->rq_disk->part0, blk_rq_bytes(rq)))
1977 : : return -EIO;
1978 : :
1979 : 0 : spin_lock_irqsave(q->queue_lock, flags);
1980 [ # # ]: 0 : if (unlikely(blk_queue_dying(q))) {
1981 : 0 : spin_unlock_irqrestore(q->queue_lock, flags);
1982 : 0 : return -ENODEV;
1983 : : }
1984 : :
1985 : : /*
1986 : : * Submitting request must be dequeued before calling this function
1987 : : * because it will be linked to another request_queue
1988 : : */
1989 [ # # ]: 0 : BUG_ON(blk_queued_rq(rq));
1990 : :
1991 [ # # ]: 0 : if (rq->cmd_flags & (REQ_FLUSH|REQ_FUA))
1992 : : where = ELEVATOR_INSERT_FLUSH;
1993 : :
1994 : : add_acct_request(q, rq, where);
1995 [ # # ]: 0 : if (where == ELEVATOR_INSERT_FLUSH)
1996 : 0 : __blk_run_queue(q);
1997 : 0 : spin_unlock_irqrestore(q->queue_lock, flags);
1998 : :
1999 : 0 : return 0;
2000 : : }
2001 : : EXPORT_SYMBOL_GPL(blk_insert_cloned_request);
2002 : :
2003 : : /**
2004 : : * blk_rq_err_bytes - determine number of bytes till the next failure boundary
2005 : : * @rq: request to examine
2006 : : *
2007 : : * Description:
2008 : : * A request could be merge of IOs which require different failure
2009 : : * handling. This function determines the number of bytes which
2010 : : * can be failed from the beginning of the request without
2011 : : * crossing into area which need to be retried further.
2012 : : *
2013 : : * Return:
2014 : : * The number of bytes to fail.
2015 : : *
2016 : : * Context:
2017 : : * queue_lock must be held.
2018 : : */
2019 : 0 : unsigned int blk_rq_err_bytes(const struct request *rq)
2020 : : {
2021 : 0 : unsigned int ff = rq->cmd_flags & REQ_FAILFAST_MASK;
2022 : : unsigned int bytes = 0;
2023 : : struct bio *bio;
2024 : :
2025 [ # # ]: 0 : if (!(rq->cmd_flags & REQ_MIXED_MERGE))
2026 : 0 : return blk_rq_bytes(rq);
2027 : :
2028 : : /*
2029 : : * Currently the only 'mixing' which can happen is between
2030 : : * different fastfail types. We can safely fail portions
2031 : : * which have all the failfast bits that the first one has -
2032 : : * the ones which are at least as eager to fail as the first
2033 : : * one.
2034 : : */
2035 [ # # ]: 0 : for (bio = rq->bio; bio; bio = bio->bi_next) {
2036 [ # # ]: 0 : if ((bio->bi_rw & ff) != ff)
2037 : : break;
2038 : 0 : bytes += bio->bi_iter.bi_size;
2039 : : }
2040 : :
2041 : : /* this could lead to infinite loop */
2042 [ # # ][ # # ]: 0 : BUG_ON(blk_rq_bytes(rq) && !bytes);
2043 : : return bytes;
2044 : : }
2045 : : EXPORT_SYMBOL_GPL(blk_rq_err_bytes);
2046 : :
2047 : 0 : void blk_account_io_completion(struct request *req, unsigned int bytes)
2048 : : {
2049 [ + - ]: 387103 : if (blk_do_io_stat(req)) {
2050 : 387103 : const int rw = rq_data_dir(req);
2051 : : struct hd_struct *part;
2052 : : int cpu;
2053 : :
2054 : 387103 : cpu = part_stat_lock();
2055 : 387103 : part = req->part;
2056 [ + - ]: 774206 : part_stat_add(cpu, part, sectors[rw], bytes >> 9);
2057 : 387103 : part_stat_unlock();
2058 : : }
2059 : 387103 : }
2060 : :
2061 : 0 : void blk_account_io_done(struct request *req)
2062 : : {
2063 : : /*
2064 : : * Account IO completion. flush_rq isn't accounted as a
2065 : : * normal IO on queueing nor completion. Accounting the
2066 : : * containing request is enough.
2067 : : */
2068 [ + + ][ + - ]: 401979 : if (blk_do_io_stat(req) && !(req->cmd_flags & REQ_FLUSH_SEQ)) {
2069 : 387103 : unsigned long duration = jiffies - req->start_time;
2070 : 387103 : const int rw = rq_data_dir(req);
2071 : : struct hd_struct *part;
2072 : : int cpu;
2073 : :
2074 : 387103 : cpu = part_stat_lock();
2075 : 387103 : part = req->part;
2076 : :
2077 [ + - ]: 774206 : part_stat_inc(cpu, part, ios[rw]);
2078 [ + - ]: 774206 : part_stat_add(cpu, part, ticks[rw], duration);
2079 : 387103 : part_round_stats(cpu, part);
2080 : : part_dec_in_flight(part, rw);
2081 : :
2082 : : hd_struct_put(part);
2083 : 387103 : part_stat_unlock();
2084 : : }
2085 : 401979 : }
2086 : :
2087 : : #ifdef CONFIG_PM_RUNTIME
2088 : : /*
2089 : : * Don't process normal requests when queue is suspended
2090 : : * or in the process of suspending/resuming
2091 : : */
2092 : : static struct request *blk_pm_peek_request(struct request_queue *q,
2093 : : struct request *rq)
2094 : : {
2095 : : if (q->dev && (q->rpm_status == RPM_SUSPENDED ||
2096 : : (q->rpm_status != RPM_ACTIVE && !(rq->cmd_flags & REQ_PM))))
2097 : : return NULL;
2098 : : else
2099 : : return rq;
2100 : : }
2101 : : #else
2102 : : static inline struct request *blk_pm_peek_request(struct request_queue *q,
2103 : : struct request *rq)
2104 : : {
2105 : : return rq;
2106 : : }
2107 : : #endif
2108 : :
2109 : 0 : void blk_account_io_start(struct request *rq, bool new_io)
2110 : : {
2111 : : struct hd_struct *part;
2112 : 454883 : int rw = rq_data_dir(rq);
2113 : : int cpu;
2114 : :
2115 [ + ]: 454883 : if (!blk_do_io_stat(rq))
2116 : 454870 : return;
2117 : :
2118 : 454896 : cpu = part_stat_lock();
2119 : :
2120 [ + + ]: 454882 : if (!new_io) {
2121 : 66965 : part = rq->part;
2122 [ + + ]: 133929 : part_stat_inc(cpu, part, merges[rw]);
2123 : : } else {
2124 : 387917 : part = disk_map_sector_rcu(rq->rq_disk, blk_rq_pos(rq));
2125 [ - + ]: 387717 : if (!hd_struct_try_get(part)) {
2126 : : /*
2127 : : * The partition is already being removed,
2128 : : * the request will be accounted on the disk only
2129 : : *
2130 : : * We take a reference on disk->part0 although that
2131 : : * partition will never be deleted, so we can treat
2132 : : * it as any other partition.
2133 : : */
2134 : 0 : part = &rq->rq_disk->part0;
2135 : : hd_struct_get(part);
2136 : : }
2137 : 387717 : part_round_stats(cpu, part);
2138 : : part_inc_in_flight(part, rw);
2139 : 387906 : rq->part = part;
2140 : : }
2141 : :
2142 : 454871 : part_stat_unlock();
2143 : : }
2144 : :
2145 : : /**
2146 : : * blk_peek_request - peek at the top of a request queue
2147 : : * @q: request queue to peek at
2148 : : *
2149 : : * Description:
2150 : : * Return the request at the top of @q. The returned request
2151 : : * should be started using blk_start_request() before LLD starts
2152 : : * processing it.
2153 : : *
2154 : : * Return:
2155 : : * Pointer to the request at the top of @q if available. Null
2156 : : * otherwise.
2157 : : *
2158 : : * Context:
2159 : : * queue_lock must be held.
2160 : : */
2161 : 0 : struct request *blk_peek_request(struct request_queue *q)
2162 : : {
2163 : 577791 : struct request *rq;
2164 : : int ret;
2165 : :
2166 [ + + ]: 2686040 : while ((rq = __elv_next_request(q)) != NULL) {
2167 : :
2168 : : rq = blk_pm_peek_request(q, rq);
2169 [ + - ]: 577791 : if (!rq)
2170 : : break;
2171 : :
2172 [ + + ]: 577791 : if (!(rq->cmd_flags & REQ_STARTED)) {
2173 : : /*
2174 : : * This is the first time the device driver
2175 : : * sees this request (possibly after
2176 : : * requeueing). Notify IO scheduler.
2177 : : */
2178 [ + + ]: 401979 : if (rq->cmd_flags & REQ_SORTED)
2179 : : elv_activate_rq(q, rq);
2180 : :
2181 : : /*
2182 : : * just mark as started even if we don't start
2183 : : * it, a request that has been delayed should
2184 : : * not be passed by new incoming requests
2185 : : */
2186 : 401979 : rq->cmd_flags |= REQ_STARTED;
2187 : : trace_block_rq_issue(q, rq);
2188 : : }
2189 : :
2190 [ - + ][ # # ]: 577791 : if (!q->boundary_rq || q->boundary_rq == rq) {
2191 : 577791 : q->end_sector = rq_end_sector(rq);
2192 : 577791 : q->boundary_rq = NULL;
2193 : : }
2194 : :
2195 [ + + ]: 577791 : if (rq->cmd_flags & REQ_DONTPREP)
2196 : : break;
2197 : :
2198 [ - + ][ # # ]: 401979 : if (q->dma_drain_size && blk_rq_bytes(rq)) {
2199 : : /*
2200 : : * make sure space for the drain appears we
2201 : : * know we can do this because max_hw_segments
2202 : : * has been adjusted to be one fewer than the
2203 : : * device can handle
2204 : : */
2205 : 0 : rq->nr_phys_segments++;
2206 : : }
2207 : :
2208 [ + - ]: 401979 : if (!q->prep_rq_fn)
2209 : : break;
2210 : :
2211 : 401979 : ret = q->prep_rq_fn(q, rq);
2212 [ - + ]: 401979 : if (ret == BLKPREP_OK) {
2213 : : break;
2214 [ # # ]: 0 : } else if (ret == BLKPREP_DEFER) {
2215 : : /*
2216 : : * the request may have been (partially) prepped.
2217 : : * we need to keep this request in the front to
2218 : : * avoid resource deadlock. REQ_STARTED will
2219 : : * prevent other fs requests from passing this one.
2220 : : */
2221 [ # # ][ # # ]: 0 : if (q->dma_drain_size && blk_rq_bytes(rq) &&
[ # # ]
2222 : 0 : !(rq->cmd_flags & REQ_DONTPREP)) {
2223 : : /*
2224 : : * remove the space for the drain we added
2225 : : * so that we don't add it again
2226 : : */
2227 : 0 : --rq->nr_phys_segments;
2228 : : }
2229 : :
2230 : : rq = NULL;
2231 : : break;
2232 [ # # ]: 0 : } else if (ret == BLKPREP_KILL) {
2233 : 0 : rq->cmd_flags |= REQ_QUIET;
2234 : : /*
2235 : : * Mark this request as started so we don't trigger
2236 : : * any debug logic in the end I/O path.
2237 : : */
2238 : 0 : blk_start_request(rq);
2239 : 0 : __blk_end_request_all(rq, -EIO);
2240 : : } else {
2241 : 0 : printk(KERN_ERR "%s: bad return=%d\n", __func__, ret);
2242 : 387103 : break;
2243 : : }
2244 : : }
2245 : :
2246 : 1343020 : return rq;
2247 : : }
2248 : : EXPORT_SYMBOL(blk_peek_request);
2249 : :
2250 : 0 : void blk_dequeue_request(struct request *rq)
2251 : : {
2252 : 401979 : struct request_queue *q = rq->q;
2253 : :
2254 [ - + ]: 401979 : BUG_ON(list_empty(&rq->queuelist));
2255 [ - + ]: 401979 : BUG_ON(ELV_ON_HASH(rq));
2256 : :
2257 : : list_del_init(&rq->queuelist);
2258 : :
2259 : : /*
2260 : : * the time frame between a request being removed from the lists
2261 : : * and to it is freed is accounted as io that is in progress at
2262 : : * the driver side.
2263 : : */
2264 [ + - ][ + ]: 401979 : if (blk_account_rq(rq)) {
2265 : 387103 : q->in_flight[rq_is_sync(rq)]++;
2266 : : set_io_start_time_ns(rq);
2267 : : }
2268 : 0 : }
2269 : :
2270 : : /**
2271 : : * blk_start_request - start request processing on the driver
2272 : : * @req: request to dequeue
2273 : : *
2274 : : * Description:
2275 : : * Dequeue @req and start timeout timer on it. This hands off the
2276 : : * request to the driver.
2277 : : *
2278 : : * Block internal functions which don't want to start timer should
2279 : : * call blk_dequeue_request().
2280 : : *
2281 : : * Context:
2282 : : * queue_lock must be held.
2283 : : */
2284 : 0 : void blk_start_request(struct request *req)
2285 : : {
2286 : 401979 : blk_dequeue_request(req);
2287 : :
2288 : : /*
2289 : : * We are now handing the request to the hardware, initialize
2290 : : * resid_len to full count and add the timeout handler.
2291 : : */
2292 : 401979 : req->resid_len = blk_rq_bytes(req);
2293 [ - + ]: 803958 : if (unlikely(blk_bidi_rq(req)))
2294 : 0 : req->next_rq->resid_len = blk_rq_bytes(req->next_rq);
2295 : :
2296 [ - + ]: 401979 : BUG_ON(test_bit(REQ_ATOM_COMPLETE, &req->atomic_flags));
2297 : 401979 : blk_add_timer(req);
2298 : 401979 : }
2299 : : EXPORT_SYMBOL(blk_start_request);
2300 : :
2301 : : /**
2302 : : * blk_fetch_request - fetch a request from a request queue
2303 : : * @q: request queue to fetch a request from
2304 : : *
2305 : : * Description:
2306 : : * Return the request at the top of @q. The request is started on
2307 : : * return and LLD can start processing it immediately.
2308 : : *
2309 : : * Return:
2310 : : * Pointer to the request at the top of @q if available. Null
2311 : : * otherwise.
2312 : : *
2313 : : * Context:
2314 : : * queue_lock must be held.
2315 : : */
2316 : 0 : struct request *blk_fetch_request(struct request_queue *q)
2317 : : {
2318 : : struct request *rq;
2319 : :
2320 : 0 : rq = blk_peek_request(q);
2321 [ # # ]: 0 : if (rq)
2322 : 0 : blk_start_request(rq);
2323 : 0 : return rq;
2324 : : }
2325 : : EXPORT_SYMBOL(blk_fetch_request);
2326 : :
2327 : : /**
2328 : : * blk_update_request - Special helper function for request stacking drivers
2329 : : * @req: the request being processed
2330 : : * @error: %0 for success, < %0 for error
2331 : : * @nr_bytes: number of bytes to complete @req
2332 : : *
2333 : : * Description:
2334 : : * Ends I/O on a number of bytes attached to @req, but doesn't complete
2335 : : * the request structure even if @req doesn't have leftover.
2336 : : * If @req has leftover, sets it up for the next range of segments.
2337 : : *
2338 : : * This special helper function is only for request stacking drivers
2339 : : * (e.g. request-based dm) so that they can handle partial completion.
2340 : : * Actual device drivers should use blk_end_request instead.
2341 : : *
2342 : : * Passing the result of blk_rq_bytes() as @nr_bytes guarantees
2343 : : * %false return from this function.
2344 : : *
2345 : : * Return:
2346 : : * %false - this request doesn't have any more data
2347 : : * %true - this request has more data
2348 : : **/
2349 : 0 : bool blk_update_request(struct request *req, int error, unsigned int nr_bytes)
2350 : : {
2351 : : int total_bytes;
2352 : :
2353 [ + + ]: 401979 : if (!req->bio)
2354 : : return false;
2355 : :
2356 : 387103 : trace_block_rq_complete(req->q, req);
2357 : :
2358 : : /*
2359 : : * For fs requests, rq is just carrier of independent bio's
2360 : : * and each partial completion should be handled separately.
2361 : : * Reset per-request error on each partial completion.
2362 : : *
2363 : : * TODO: tj: This is too subtle. It would be better to let
2364 : : * low level drivers do what they see fit.
2365 : : */
2366 [ + - ]: 387103 : if (req->cmd_type == REQ_TYPE_FS)
2367 : 387103 : req->errors = 0;
2368 : :
2369 [ - + ][ # # ]: 387103 : if (error && req->cmd_type == REQ_TYPE_FS &&
[ # # ]
2370 : 0 : !(req->cmd_flags & REQ_QUIET)) {
2371 : : char *error_type;
2372 : :
2373 [ # # # # : 0 : switch (error) {
# # # ]
2374 : : case -ENOLINK:
2375 : : error_type = "recoverable transport";
2376 : : break;
2377 : : case -EREMOTEIO:
2378 : : error_type = "critical target";
2379 : 0 : break;
2380 : : case -EBADE:
2381 : : error_type = "critical nexus";
2382 : 0 : break;
2383 : : case -ETIMEDOUT:
2384 : : error_type = "timeout";
2385 : 0 : break;
2386 : : case -ENOSPC:
2387 : : error_type = "critical space allocation";
2388 : 0 : break;
2389 : : case -ENODATA:
2390 : : error_type = "critical medium";
2391 : 0 : break;
2392 : : case -EIO:
2393 : : default:
2394 : : error_type = "I/O";
2395 : 0 : break;
2396 : : }
2397 [ # # ][ # # ]: 0 : printk_ratelimited(KERN_ERR "end_request: %s error, dev %s, sector %llu\n",
2398 : : error_type, req->rq_disk ?
2399 : : req->rq_disk->disk_name : "?",
2400 : : (unsigned long long)blk_rq_pos(req));
2401 : :
2402 : : }
2403 : :
2404 : 387103 : blk_account_io_completion(req, nr_bytes);
2405 : :
2406 : : total_bytes = 0;
2407 [ + - ]: 454917 : while (req->bio) {
2408 : : struct bio *bio = req->bio;
2409 : 454917 : unsigned bio_bytes = min(bio->bi_iter.bi_size, nr_bytes);
2410 : :
2411 [ + - ]: 454917 : if (bio_bytes == bio->bi_iter.bi_size)
2412 : 454917 : req->bio = bio->bi_next;
2413 : :
2414 : 454917 : req_bio_endio(req, bio, bio_bytes, error);
2415 : :
2416 : 454917 : total_bytes += bio_bytes;
2417 : 454917 : nr_bytes -= bio_bytes;
2418 : :
2419 [ + + ]: 454917 : if (!nr_bytes)
2420 : : break;
2421 : : }
2422 : :
2423 : : /*
2424 : : * completely done
2425 : : */
2426 [ + - ]: 387103 : if (!req->bio) {
2427 : : /*
2428 : : * Reset counters so that the request stacking driver
2429 : : * can find how many bytes remain in the request
2430 : : * later.
2431 : : */
2432 : 387103 : req->__data_len = 0;
2433 : 387103 : return false;
2434 : : }
2435 : :
2436 : 0 : req->__data_len -= total_bytes;
2437 : 0 : req->buffer = bio_data(req->bio);
2438 : :
2439 : : /* update sector only for requests with clear definition of sector */
2440 [ # # ]: 0 : if (req->cmd_type == REQ_TYPE_FS)
2441 : 0 : req->__sector += total_bytes >> 9;
2442 : :
2443 : : /* mixed attributes always follow the first bio */
2444 [ # # ]: 0 : if (req->cmd_flags & REQ_MIXED_MERGE) {
2445 : 0 : req->cmd_flags &= ~REQ_FAILFAST_MASK;
2446 : 0 : req->cmd_flags |= req->bio->bi_rw & REQ_FAILFAST_MASK;
2447 : : }
2448 : :
2449 : : /*
2450 : : * If total number of sectors is less than the first segment
2451 : : * size, something has gone terribly wrong.
2452 : : */
2453 [ # # ]: 0 : if (blk_rq_bytes(req) < blk_rq_cur_bytes(req)) {
2454 : 0 : blk_dump_rq_flags(req, "request botched");
2455 : 0 : req->__data_len = blk_rq_cur_bytes(req);
2456 : : }
2457 : :
2458 : : /* recalculate the number of segments */
2459 : 0 : blk_recalc_rq_segments(req);
2460 : :
2461 : 0 : return true;
2462 : : }
2463 : : EXPORT_SYMBOL_GPL(blk_update_request);
2464 : :
2465 : 0 : static bool blk_update_bidi_request(struct request *rq, int error,
2466 : : unsigned int nr_bytes,
2467 : : unsigned int bidi_bytes)
2468 : : {
2469 [ + - ]: 401979 : if (blk_update_request(rq, error, nr_bytes))
2470 : : return true;
2471 : :
2472 : : /* Bidi request must be completed as a whole */
2473 [ - + # # ]: 401979 : if (unlikely(blk_bidi_rq(rq)) &&
2474 : 0 : blk_update_request(rq->next_rq, error, bidi_bytes))
2475 : : return true;
2476 : :
2477 [ + - ]: 401979 : if (blk_queue_add_random(rq->q))
2478 : 401979 : add_disk_randomness(rq->rq_disk);
2479 : :
2480 : : return false;
2481 : : }
2482 : :
2483 : : /**
2484 : : * blk_unprep_request - unprepare a request
2485 : : * @req: the request
2486 : : *
2487 : : * This function makes a request ready for complete resubmission (or
2488 : : * completion). It happens only after all error handling is complete,
2489 : : * so represents the appropriate moment to deallocate any resources
2490 : : * that were allocated to the request in the prep_rq_fn. The queue
2491 : : * lock is held when calling this.
2492 : : */
2493 : 0 : void blk_unprep_request(struct request *req)
2494 : : {
2495 : 401979 : struct request_queue *q = req->q;
2496 : :
2497 : 401979 : req->cmd_flags &= ~REQ_DONTPREP;
2498 [ + - ][ # # ]: 401979 : if (q->unprep_rq_fn)
2499 : 401979 : q->unprep_rq_fn(q, req);
2500 : 0 : }
2501 : : EXPORT_SYMBOL_GPL(blk_unprep_request);
2502 : :
2503 : : /*
2504 : : * queue lock must be held
2505 : : */
2506 : 0 : static void blk_finish_request(struct request *req, int error)
2507 : : {
2508 [ - + ]: 401979 : if (blk_rq_tagged(req))
2509 : 0 : blk_queue_end_tag(req->q, req);
2510 : :
2511 [ - + ]: 401979 : BUG_ON(blk_queued_rq(req));
2512 : :
2513 [ - + ][ # # ]: 401979 : if (unlikely(laptop_mode) && req->cmd_type == REQ_TYPE_FS)
2514 : 0 : laptop_io_completion(&req->q->backing_dev_info);
2515 : :
2516 : 401979 : blk_delete_timer(req);
2517 : :
2518 [ + - ]: 401979 : if (req->cmd_flags & REQ_DONTPREP)
2519 : : blk_unprep_request(req);
2520 : :
2521 : 401979 : blk_account_io_done(req);
2522 : :
2523 [ + + ]: 401979 : if (req->end_io)
2524 : 14876 : req->end_io(req, error);
2525 : : else {
2526 [ - + ]: 387103 : if (blk_bidi_rq(req))
2527 : 0 : __blk_put_request(req->next_rq->q, req->next_rq);
2528 : :
2529 : 387103 : __blk_put_request(req->q, req);
2530 : : }
2531 : 401979 : }
2532 : :
2533 : : /**
2534 : : * blk_end_bidi_request - Complete a bidi request
2535 : : * @rq: the request to complete
2536 : : * @error: %0 for success, < %0 for error
2537 : : * @nr_bytes: number of bytes to complete @rq
2538 : : * @bidi_bytes: number of bytes to complete @rq->next_rq
2539 : : *
2540 : : * Description:
2541 : : * Ends I/O on a number of bytes attached to @rq and @rq->next_rq.
2542 : : * Drivers that supports bidi can safely call this member for any
2543 : : * type of request, bidi or uni. In the later case @bidi_bytes is
2544 : : * just ignored.
2545 : : *
2546 : : * Return:
2547 : : * %false - we are done with this request
2548 : : * %true - still buffers pending for this request
2549 : : **/
2550 : 0 : static bool blk_end_bidi_request(struct request *rq, int error,
2551 : : unsigned int nr_bytes, unsigned int bidi_bytes)
2552 : : {
2553 : 401979 : struct request_queue *q = rq->q;
2554 : : unsigned long flags;
2555 : :
2556 [ + - ]: 401979 : if (blk_update_bidi_request(rq, error, nr_bytes, bidi_bytes))
2557 : : return true;
2558 : :
2559 : 401979 : spin_lock_irqsave(q->queue_lock, flags);
2560 : 401979 : blk_finish_request(rq, error);
2561 : 401979 : spin_unlock_irqrestore(q->queue_lock, flags);
2562 : :
2563 : 401979 : return false;
2564 : : }
2565 : :
2566 : : /**
2567 : : * __blk_end_bidi_request - Complete a bidi request with queue lock held
2568 : : * @rq: the request to complete
2569 : : * @error: %0 for success, < %0 for error
2570 : : * @nr_bytes: number of bytes to complete @rq
2571 : : * @bidi_bytes: number of bytes to complete @rq->next_rq
2572 : : *
2573 : : * Description:
2574 : : * Identical to blk_end_bidi_request() except that queue lock is
2575 : : * assumed to be locked on entry and remains so on return.
2576 : : *
2577 : : * Return:
2578 : : * %false - we are done with this request
2579 : : * %true - still buffers pending for this request
2580 : : **/
2581 : 0 : bool __blk_end_bidi_request(struct request *rq, int error,
2582 : : unsigned int nr_bytes, unsigned int bidi_bytes)
2583 : : {
2584 [ # # ]: 0 : if (blk_update_bidi_request(rq, error, nr_bytes, bidi_bytes))
2585 : : return true;
2586 : :
2587 : 0 : blk_finish_request(rq, error);
2588 : :
2589 : 0 : return false;
2590 : : }
2591 : :
2592 : : /**
2593 : : * blk_end_request - Helper function for drivers to complete the request.
2594 : : * @rq: the request being processed
2595 : : * @error: %0 for success, < %0 for error
2596 : : * @nr_bytes: number of bytes to complete
2597 : : *
2598 : : * Description:
2599 : : * Ends I/O on a number of bytes attached to @rq.
2600 : : * If @rq has leftover, sets it up for the next range of segments.
2601 : : *
2602 : : * Return:
2603 : : * %false - we are done with this request
2604 : : * %true - still buffers pending for this request
2605 : : **/
2606 : 0 : bool blk_end_request(struct request *rq, int error, unsigned int nr_bytes)
2607 : : {
2608 : 401979 : return blk_end_bidi_request(rq, error, nr_bytes, 0);
2609 : : }
2610 : : EXPORT_SYMBOL(blk_end_request);
2611 : :
2612 : : /**
2613 : : * blk_end_request_all - Helper function for drives to finish the request.
2614 : : * @rq: the request to finish
2615 : : * @error: %0 for success, < %0 for error
2616 : : *
2617 : : * Description:
2618 : : * Completely finish @rq.
2619 : : */
2620 : 0 : void blk_end_request_all(struct request *rq, int error)
2621 : : {
2622 : : bool pending;
2623 : : unsigned int bidi_bytes = 0;
2624 : :
2625 [ # # ]: 0 : if (unlikely(blk_bidi_rq(rq)))
2626 : : bidi_bytes = blk_rq_bytes(rq->next_rq);
2627 : :
2628 : 0 : pending = blk_end_bidi_request(rq, error, blk_rq_bytes(rq), bidi_bytes);
2629 [ # # ]: 0 : BUG_ON(pending);
2630 : 0 : }
2631 : : EXPORT_SYMBOL(blk_end_request_all);
2632 : :
2633 : : /**
2634 : : * blk_end_request_cur - Helper function to finish the current request chunk.
2635 : : * @rq: the request to finish the current chunk for
2636 : : * @error: %0 for success, < %0 for error
2637 : : *
2638 : : * Description:
2639 : : * Complete the current consecutively mapped chunk from @rq.
2640 : : *
2641 : : * Return:
2642 : : * %false - we are done with this request
2643 : : * %true - still buffers pending for this request
2644 : : */
2645 : 0 : bool blk_end_request_cur(struct request *rq, int error)
2646 : : {
2647 : 0 : return blk_end_request(rq, error, blk_rq_cur_bytes(rq));
2648 : : }
2649 : : EXPORT_SYMBOL(blk_end_request_cur);
2650 : :
2651 : : /**
2652 : : * blk_end_request_err - Finish a request till the next failure boundary.
2653 : : * @rq: the request to finish till the next failure boundary for
2654 : : * @error: must be negative errno
2655 : : *
2656 : : * Description:
2657 : : * Complete @rq till the next failure boundary.
2658 : : *
2659 : : * Return:
2660 : : * %false - we are done with this request
2661 : : * %true - still buffers pending for this request
2662 : : */
2663 : 0 : bool blk_end_request_err(struct request *rq, int error)
2664 : : {
2665 [ # # ]: 0 : WARN_ON(error >= 0);
2666 : 0 : return blk_end_request(rq, error, blk_rq_err_bytes(rq));
2667 : : }
2668 : : EXPORT_SYMBOL_GPL(blk_end_request_err);
2669 : :
2670 : : /**
2671 : : * __blk_end_request - Helper function for drivers to complete the request.
2672 : : * @rq: the request being processed
2673 : : * @error: %0 for success, < %0 for error
2674 : : * @nr_bytes: number of bytes to complete
2675 : : *
2676 : : * Description:
2677 : : * Must be called with queue lock held unlike blk_end_request().
2678 : : *
2679 : : * Return:
2680 : : * %false - we are done with this request
2681 : : * %true - still buffers pending for this request
2682 : : **/
2683 : 0 : bool __blk_end_request(struct request *rq, int error, unsigned int nr_bytes)
2684 : : {
2685 : 0 : return __blk_end_bidi_request(rq, error, nr_bytes, 0);
2686 : : }
2687 : : EXPORT_SYMBOL(__blk_end_request);
2688 : :
2689 : : /**
2690 : : * __blk_end_request_all - Helper function for drives to finish the request.
2691 : : * @rq: the request to finish
2692 : : * @error: %0 for success, < %0 for error
2693 : : *
2694 : : * Description:
2695 : : * Completely finish @rq. Must be called with queue lock held.
2696 : : */
2697 : 0 : void __blk_end_request_all(struct request *rq, int error)
2698 : : {
2699 : : bool pending;
2700 : : unsigned int bidi_bytes = 0;
2701 : :
2702 [ # # ]: 0 : if (unlikely(blk_bidi_rq(rq)))
2703 : : bidi_bytes = blk_rq_bytes(rq->next_rq);
2704 : :
2705 : 0 : pending = __blk_end_bidi_request(rq, error, blk_rq_bytes(rq), bidi_bytes);
2706 [ # # ]: 0 : BUG_ON(pending);
2707 : 0 : }
2708 : : EXPORT_SYMBOL(__blk_end_request_all);
2709 : :
2710 : : /**
2711 : : * __blk_end_request_cur - Helper function to finish the current request chunk.
2712 : : * @rq: the request to finish the current chunk for
2713 : : * @error: %0 for success, < %0 for error
2714 : : *
2715 : : * Description:
2716 : : * Complete the current consecutively mapped chunk from @rq. Must
2717 : : * be called with queue lock held.
2718 : : *
2719 : : * Return:
2720 : : * %false - we are done with this request
2721 : : * %true - still buffers pending for this request
2722 : : */
2723 : 0 : bool __blk_end_request_cur(struct request *rq, int error)
2724 : : {
2725 : 0 : return __blk_end_request(rq, error, blk_rq_cur_bytes(rq));
2726 : : }
2727 : : EXPORT_SYMBOL(__blk_end_request_cur);
2728 : :
2729 : : /**
2730 : : * __blk_end_request_err - Finish a request till the next failure boundary.
2731 : : * @rq: the request to finish till the next failure boundary for
2732 : : * @error: must be negative errno
2733 : : *
2734 : : * Description:
2735 : : * Complete @rq till the next failure boundary. Must be called
2736 : : * with queue lock held.
2737 : : *
2738 : : * Return:
2739 : : * %false - we are done with this request
2740 : : * %true - still buffers pending for this request
2741 : : */
2742 : 0 : bool __blk_end_request_err(struct request *rq, int error)
2743 : : {
2744 [ # # ]: 0 : WARN_ON(error >= 0);
2745 : 0 : return __blk_end_request(rq, error, blk_rq_err_bytes(rq));
2746 : : }
2747 : : EXPORT_SYMBOL_GPL(__blk_end_request_err);
2748 : :
2749 : 0 : void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
2750 : : struct bio *bio)
2751 : : {
2752 : : /* Bit 0 (R/W) is identical in rq->cmd_flags and bio->bi_rw */
2753 : 387919 : rq->cmd_flags |= bio->bi_rw & REQ_WRITE;
2754 : :
2755 [ + + ]: 387919 : if (bio_has_data(bio)) {
2756 : 387907 : rq->nr_phys_segments = bio_phys_segments(q, bio);
2757 : 387915 : rq->buffer = bio_data(bio);
2758 : : }
2759 : 387927 : rq->__data_len = bio->bi_iter.bi_size;
2760 : 387927 : rq->bio = rq->biotail = bio;
2761 : :
2762 [ + + ]: 387927 : if (bio->bi_bdev)
2763 : 387917 : rq->rq_disk = bio->bi_bdev->bd_disk;
2764 : 8 : }
2765 : :
2766 : : #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
2767 : : /**
2768 : : * rq_flush_dcache_pages - Helper function to flush all pages in a request
2769 : : * @rq: the request to be flushed
2770 : : *
2771 : : * Description:
2772 : : * Flush all pages in @rq.
2773 : : */
2774 : 0 : void rq_flush_dcache_pages(struct request *rq)
2775 : : {
2776 : : struct req_iterator iter;
2777 : : struct bio_vec bvec;
2778 : :
2779 [ # # ][ # # ]: 0 : rq_for_each_segment(bvec, rq, iter)
[ # # ]
2780 : 0 : flush_dcache_page(bvec.bv_page);
2781 : 0 : }
2782 : : EXPORT_SYMBOL_GPL(rq_flush_dcache_pages);
2783 : : #endif
2784 : :
2785 : : /**
2786 : : * blk_lld_busy - Check if underlying low-level drivers of a device are busy
2787 : : * @q : the queue of the device being checked
2788 : : *
2789 : : * Description:
2790 : : * Check if underlying low-level drivers of a device are busy.
2791 : : * If the drivers want to export their busy state, they must set own
2792 : : * exporting function using blk_queue_lld_busy() first.
2793 : : *
2794 : : * Basically, this function is used only by request stacking drivers
2795 : : * to stop dispatching requests to underlying devices when underlying
2796 : : * devices are busy. This behavior helps more I/O merging on the queue
2797 : : * of the request stacking driver and prevents I/O throughput regression
2798 : : * on burst I/O load.
2799 : : *
2800 : : * Return:
2801 : : * 0 - Not busy (The request stacking driver should dispatch request)
2802 : : * 1 - Busy (The request stacking driver should stop dispatching request)
2803 : : */
2804 : 0 : int blk_lld_busy(struct request_queue *q)
2805 : : {
2806 [ # # ]: 0 : if (q->lld_busy_fn)
2807 : 0 : return q->lld_busy_fn(q);
2808 : :
2809 : : return 0;
2810 : : }
2811 : : EXPORT_SYMBOL_GPL(blk_lld_busy);
2812 : :
2813 : : /**
2814 : : * blk_rq_unprep_clone - Helper function to free all bios in a cloned request
2815 : : * @rq: the clone request to be cleaned up
2816 : : *
2817 : : * Description:
2818 : : * Free all bios in @rq for a cloned request.
2819 : : */
2820 : 0 : void blk_rq_unprep_clone(struct request *rq)
2821 : : {
2822 : : struct bio *bio;
2823 : :
2824 [ # # ][ # # ]: 0 : while ((bio = rq->bio) != NULL) {
2825 : 0 : rq->bio = bio->bi_next;
2826 : :
2827 : 0 : bio_put(bio);
2828 : : }
2829 : 0 : }
2830 : : EXPORT_SYMBOL_GPL(blk_rq_unprep_clone);
2831 : :
2832 : : /*
2833 : : * Copy attributes of the original request to the clone request.
2834 : : * The actual data parts (e.g. ->cmd, ->buffer, ->sense) are not copied.
2835 : : */
2836 : 0 : static void __blk_rq_prep_clone(struct request *dst, struct request *src)
2837 : : {
2838 : 0 : dst->cpu = src->cpu;
2839 : 0 : dst->cmd_flags = (src->cmd_flags & REQ_CLONE_MASK) | REQ_NOMERGE;
2840 : 0 : dst->cmd_type = src->cmd_type;
2841 : 0 : dst->__sector = blk_rq_pos(src);
2842 : 0 : dst->__data_len = blk_rq_bytes(src);
2843 : 0 : dst->nr_phys_segments = src->nr_phys_segments;
2844 : 0 : dst->ioprio = src->ioprio;
2845 : 0 : dst->extra_len = src->extra_len;
2846 : : }
2847 : :
2848 : : /**
2849 : : * blk_rq_prep_clone - Helper function to setup clone request
2850 : : * @rq: the request to be setup
2851 : : * @rq_src: original request to be cloned
2852 : : * @bs: bio_set that bios for clone are allocated from
2853 : : * @gfp_mask: memory allocation mask for bio
2854 : : * @bio_ctr: setup function to be called for each clone bio.
2855 : : * Returns %0 for success, non %0 for failure.
2856 : : * @data: private data to be passed to @bio_ctr
2857 : : *
2858 : : * Description:
2859 : : * Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq.
2860 : : * The actual data parts of @rq_src (e.g. ->cmd, ->buffer, ->sense)
2861 : : * are not copied, and copying such parts is the caller's responsibility.
2862 : : * Also, pages which the original bios are pointing to are not copied
2863 : : * and the cloned bios just point same pages.
2864 : : * So cloned bios must be completed before original bios, which means
2865 : : * the caller must complete @rq before @rq_src.
2866 : : */
2867 : 0 : int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
2868 : : struct bio_set *bs, gfp_t gfp_mask,
2869 : : int (*bio_ctr)(struct bio *, struct bio *, void *),
2870 : : void *data)
2871 : : {
2872 : : struct bio *bio, *bio_src;
2873 : :
2874 [ # # ]: 0 : if (!bs)
2875 : 0 : bs = fs_bio_set;
2876 : :
2877 : 0 : blk_rq_init(NULL, rq);
2878 : :
2879 [ # # ][ # # ]: 0 : __rq_for_each_bio(bio_src, rq_src) {
2880 : 0 : bio = bio_clone_bioset(bio_src, gfp_mask, bs);
2881 [ # # ]: 0 : if (!bio)
2882 : : goto free_and_out;
2883 : :
2884 [ # # ][ # # ]: 0 : if (bio_ctr && bio_ctr(bio, bio_src, data))
2885 : : goto free_and_out;
2886 : :
2887 [ # # ]: 0 : if (rq->bio) {
2888 : 0 : rq->biotail->bi_next = bio;
2889 : 0 : rq->biotail = bio;
2890 : : } else
2891 : 0 : rq->bio = rq->biotail = bio;
2892 : : }
2893 : :
2894 : : __blk_rq_prep_clone(rq, rq_src);
2895 : :
2896 : 0 : return 0;
2897 : :
2898 : : free_and_out:
2899 [ # # ]: 0 : if (bio)
2900 : 0 : bio_put(bio);
2901 : : blk_rq_unprep_clone(rq);
2902 : :
2903 : : return -ENOMEM;
2904 : : }
2905 : : EXPORT_SYMBOL_GPL(blk_rq_prep_clone);
2906 : :
2907 : 0 : int kblockd_schedule_work(struct request_queue *q, struct work_struct *work)
2908 : : {
2909 : 435446 : return queue_work(kblockd_workqueue, work);
2910 : : }
2911 : : EXPORT_SYMBOL(kblockd_schedule_work);
2912 : :
2913 : 0 : int kblockd_schedule_delayed_work(struct request_queue *q,
2914 : : struct delayed_work *dwork, unsigned long delay)
2915 : : {
2916 : 0 : return queue_delayed_work(kblockd_workqueue, dwork, delay);
2917 : : }
2918 : : EXPORT_SYMBOL(kblockd_schedule_delayed_work);
2919 : :
2920 : : #define PLUG_MAGIC 0x91827364
2921 : :
2922 : : /**
2923 : : * blk_start_plug - initialize blk_plug and track it inside the task_struct
2924 : : * @plug: The &struct blk_plug that needs to be initialized
2925 : : *
2926 : : * Description:
2927 : : * Tracking blk_plug inside the task_struct will help with auto-flushing the
2928 : : * pending I/O should the task end up blocking between blk_start_plug() and
2929 : : * blk_finish_plug(). This is important from a performance perspective, but
2930 : : * also ensures that we don't deadlock. For instance, if the task is blocking
2931 : : * for a memory allocation, memory reclaim could end up wanting to free a
2932 : : * page belonging to that request that is currently residing in our private
2933 : : * plug. By flushing the pending I/O when the process goes to sleep, we avoid
2934 : : * this kind of deadlock.
2935 : : */
2936 : 0 : void blk_start_plug(struct blk_plug *plug)
2937 : : {
2938 : 604916 : struct task_struct *tsk = current;
2939 : :
2940 : 604916 : plug->magic = PLUG_MAGIC;
2941 : 604916 : INIT_LIST_HEAD(&plug->list);
2942 : 604916 : INIT_LIST_HEAD(&plug->mq_list);
2943 : 604916 : INIT_LIST_HEAD(&plug->cb_list);
2944 : :
2945 : : /*
2946 : : * If this is a nested plug, don't actually assign it. It will be
2947 : : * flushed on its own.
2948 : : */
2949 [ + + ]: 604916 : if (!tsk->plug) {
2950 : : /*
2951 : : * Store ordering should not be needed here, since a potential
2952 : : * preempt will imply a full memory barrier
2953 : : */
2954 : 505851 : tsk->plug = plug;
2955 : : }
2956 : 0 : }
2957 : : EXPORT_SYMBOL(blk_start_plug);
2958 : :
2959 : 0 : static int plug_rq_cmp(void *priv, struct list_head *a, struct list_head *b)
2960 : : {
2961 : 619608 : struct request *rqa = container_of(a, struct request, queuelist);
2962 : 619608 : struct request *rqb = container_of(b, struct request, queuelist);
2963 : :
2964 [ + ][ + + ]: 619620 : return !(rqa->q < rqb->q ||
2965 [ + + ]: 619601 : (rqa->q == rqb->q && blk_rq_pos(rqa) < blk_rq_pos(rqb)));
2966 : : }
2967 : :
2968 : : /*
2969 : : * If 'from_schedule' is true, then postpone the dispatch of requests
2970 : : * until a safe kblockd context. We due this to avoid accidental big
2971 : : * additional stack usage in driver dispatch, in places where the originally
2972 : : * plugger did not intend it.
2973 : : */
2974 : 0 : static void queue_unplugged(struct request_queue *q, unsigned int depth,
2975 : : bool from_schedule)
2976 : : __releases(q->queue_lock)
2977 : : {
2978 : 234242 : trace_block_unplug(q, depth, !from_schedule);
2979 : :
2980 [ + + ]: 234242 : if (from_schedule)
2981 : 1233 : blk_run_queue_async(q);
2982 : : else
2983 : 233009 : __blk_run_queue(q);
2984 : 234242 : spin_unlock(q->queue_lock);
2985 : 234242 : }
2986 : :
2987 : 0 : static void flush_plug_callbacks(struct blk_plug *plug, bool from_schedule)
2988 : : {
2989 : 727989 : LIST_HEAD(callbacks);
2990 : :
2991 [ - + ]: 727989 : while (!list_empty(&plug->cb_list)) {
2992 : : list_splice_init(&plug->cb_list, &callbacks);
2993 : :
2994 [ # # ]: 727989 : while (!list_empty(&callbacks)) {
2995 : : struct blk_plug_cb *cb = list_first_entry(&callbacks,
2996 : : struct blk_plug_cb,
2997 : : list);
2998 : : list_del(&cb->list);
2999 : 0 : cb->callback(cb, from_schedule);
3000 : : }
3001 : : }
3002 : 727989 : }
3003 : :
3004 : 0 : struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug, void *data,
3005 : : int size)
3006 : : {
3007 : 0 : struct blk_plug *plug = current->plug;
3008 : : struct blk_plug_cb *cb;
3009 : :
3010 [ # # ]: 0 : if (!plug)
3011 : : return NULL;
3012 : :
3013 [ # # ]: 0 : list_for_each_entry(cb, &plug->cb_list, list)
3014 [ # # ][ # # ]: 0 : if (cb->callback == unplug && cb->data == data)
3015 : : return cb;
3016 : :
3017 : : /* Not currently on the callback list */
3018 [ # # ]: 0 : BUG_ON(size < sizeof(*cb));
3019 : : cb = kzalloc(size, GFP_ATOMIC);
3020 [ # # ]: 0 : if (cb) {
3021 : 0 : cb->data = data;
3022 : 0 : cb->callback = unplug;
3023 : 0 : list_add(&cb->list, &plug->cb_list);
3024 : : }
3025 : 0 : return cb;
3026 : : }
3027 : : EXPORT_SYMBOL(blk_check_plugged);
3028 : :
3029 : 0 : void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule)
3030 : : {
3031 : : struct request_queue *q;
3032 : : unsigned long flags;
3033 : : struct request *rq;
3034 : 727982 : LIST_HEAD(list);
3035 : : unsigned int depth;
3036 : :
3037 [ - + ]: 727982 : BUG_ON(plug->magic != PLUG_MAGIC);
3038 : :
3039 : 727982 : flush_plug_callbacks(plug, from_schedule);
3040 : :
3041 [ - + ]: 727923 : if (!list_empty(&plug->mq_list))
3042 : 0 : blk_mq_flush_plug_list(plug, from_schedule);
3043 : :
3044 [ + + ]: 1455942 : if (list_empty(&plug->list))
3045 : 493771 : return;
3046 : :
3047 : : list_splice_init(&plug->list, &list);
3048 : :
3049 : 234189 : list_sort(NULL, &list, plug_rq_cmp);
3050 : :
3051 : : q = NULL;
3052 : : depth = 0;
3053 : :
3054 : : /*
3055 : : * Save and disable interrupts here, to avoid doing it for every
3056 : : * queue lock we have to take.
3057 : : */
3058 : : local_irq_save(flags);
3059 [ + + ]: 601567 : while (!list_empty(&list)) {
3060 : : rq = list_entry_rq(list.next);
3061 : 367325 : list_del_init(&rq->queuelist);
3062 [ - + ]: 367325 : BUG_ON(!rq->q);
3063 [ + + ]: 367325 : if (rq->q != q) {
3064 : : /*
3065 : : * This drops the queue lock
3066 : : */
3067 [ - + ]: 234239 : if (q)
3068 : 0 : queue_unplugged(q, depth, from_schedule);
3069 : 234239 : q = rq->q;
3070 : : depth = 0;
3071 : 234239 : spin_lock(q->queue_lock);
3072 : : }
3073 : :
3074 : : /*
3075 : : * Short-circuit if @q is dead
3076 : : */
3077 [ - + ]: 367332 : if (unlikely(blk_queue_dying(q))) {
3078 : 0 : __blk_end_request_all(rq, -ENODEV);
3079 : 0 : continue;
3080 : : }
3081 : :
3082 : : /*
3083 : : * rq is already accounted, so use raw insert
3084 : : */
3085 [ - + ]: 367332 : if (rq->cmd_flags & (REQ_FLUSH | REQ_FUA))
3086 : 0 : __elv_add_request(q, rq, ELEVATOR_INSERT_FLUSH);
3087 : : else
3088 : 367332 : __elv_add_request(q, rq, ELEVATOR_INSERT_SORT_MERGE);
3089 : :
3090 : 367332 : depth++;
3091 : : }
3092 : :
3093 : : /*
3094 : : * This drops the queue lock
3095 : : */
3096 [ + - ]: 234242 : if (q)
3097 : 234242 : queue_unplugged(q, depth, from_schedule);
3098 : :
3099 [ - + ]: 234242 : local_irq_restore(flags);
3100 : : }
3101 : :
3102 : 0 : void blk_finish_plug(struct blk_plug *plug)
3103 : : {
3104 : 604936 : blk_flush_plug_list(plug, false);
3105 : :
3106 [ + + ]: 604974 : if (plug == current->plug)
3107 : 505881 : current->plug = NULL;
3108 : 38 : }
3109 : : EXPORT_SYMBOL(blk_finish_plug);
3110 : :
3111 : : #ifdef CONFIG_PM_RUNTIME
3112 : : /**
3113 : : * blk_pm_runtime_init - Block layer runtime PM initialization routine
3114 : : * @q: the queue of the device
3115 : : * @dev: the device the queue belongs to
3116 : : *
3117 : : * Description:
3118 : : * Initialize runtime-PM-related fields for @q and start auto suspend for
3119 : : * @dev. Drivers that want to take advantage of request-based runtime PM
3120 : : * should call this function after @dev has been initialized, and its
3121 : : * request queue @q has been allocated, and runtime PM for it can not happen
3122 : : * yet(either due to disabled/forbidden or its usage_count > 0). In most
3123 : : * cases, driver should call this function before any I/O has taken place.
3124 : : *
3125 : : * This function takes care of setting up using auto suspend for the device,
3126 : : * the autosuspend delay is set to -1 to make runtime suspend impossible
3127 : : * until an updated value is either set by user or by driver. Drivers do
3128 : : * not need to touch other autosuspend settings.
3129 : : *
3130 : : * The block layer runtime PM is request based, so only works for drivers
3131 : : * that use request as their IO unit instead of those directly use bio's.
3132 : : */
3133 : : void blk_pm_runtime_init(struct request_queue *q, struct device *dev)
3134 : : {
3135 : : q->dev = dev;
3136 : : q->rpm_status = RPM_ACTIVE;
3137 : : pm_runtime_set_autosuspend_delay(q->dev, -1);
3138 : : pm_runtime_use_autosuspend(q->dev);
3139 : : }
3140 : : EXPORT_SYMBOL(blk_pm_runtime_init);
3141 : :
3142 : : /**
3143 : : * blk_pre_runtime_suspend - Pre runtime suspend check
3144 : : * @q: the queue of the device
3145 : : *
3146 : : * Description:
3147 : : * This function will check if runtime suspend is allowed for the device
3148 : : * by examining if there are any requests pending in the queue. If there
3149 : : * are requests pending, the device can not be runtime suspended; otherwise,
3150 : : * the queue's status will be updated to SUSPENDING and the driver can
3151 : : * proceed to suspend the device.
3152 : : *
3153 : : * For the not allowed case, we mark last busy for the device so that
3154 : : * runtime PM core will try to autosuspend it some time later.
3155 : : *
3156 : : * This function should be called near the start of the device's
3157 : : * runtime_suspend callback.
3158 : : *
3159 : : * Return:
3160 : : * 0 - OK to runtime suspend the device
3161 : : * -EBUSY - Device should not be runtime suspended
3162 : : */
3163 : : int blk_pre_runtime_suspend(struct request_queue *q)
3164 : : {
3165 : : int ret = 0;
3166 : :
3167 : : spin_lock_irq(q->queue_lock);
3168 : : if (q->nr_pending) {
3169 : : ret = -EBUSY;
3170 : : pm_runtime_mark_last_busy(q->dev);
3171 : : } else {
3172 : : q->rpm_status = RPM_SUSPENDING;
3173 : : }
3174 : : spin_unlock_irq(q->queue_lock);
3175 : : return ret;
3176 : : }
3177 : : EXPORT_SYMBOL(blk_pre_runtime_suspend);
3178 : :
3179 : : /**
3180 : : * blk_post_runtime_suspend - Post runtime suspend processing
3181 : : * @q: the queue of the device
3182 : : * @err: return value of the device's runtime_suspend function
3183 : : *
3184 : : * Description:
3185 : : * Update the queue's runtime status according to the return value of the
3186 : : * device's runtime suspend function and mark last busy for the device so
3187 : : * that PM core will try to auto suspend the device at a later time.
3188 : : *
3189 : : * This function should be called near the end of the device's
3190 : : * runtime_suspend callback.
3191 : : */
3192 : : void blk_post_runtime_suspend(struct request_queue *q, int err)
3193 : : {
3194 : : spin_lock_irq(q->queue_lock);
3195 : : if (!err) {
3196 : : q->rpm_status = RPM_SUSPENDED;
3197 : : } else {
3198 : : q->rpm_status = RPM_ACTIVE;
3199 : : pm_runtime_mark_last_busy(q->dev);
3200 : : }
3201 : : spin_unlock_irq(q->queue_lock);
3202 : : }
3203 : : EXPORT_SYMBOL(blk_post_runtime_suspend);
3204 : :
3205 : : /**
3206 : : * blk_pre_runtime_resume - Pre runtime resume processing
3207 : : * @q: the queue of the device
3208 : : *
3209 : : * Description:
3210 : : * Update the queue's runtime status to RESUMING in preparation for the
3211 : : * runtime resume of the device.
3212 : : *
3213 : : * This function should be called near the start of the device's
3214 : : * runtime_resume callback.
3215 : : */
3216 : : void blk_pre_runtime_resume(struct request_queue *q)
3217 : : {
3218 : : spin_lock_irq(q->queue_lock);
3219 : : q->rpm_status = RPM_RESUMING;
3220 : : spin_unlock_irq(q->queue_lock);
3221 : : }
3222 : : EXPORT_SYMBOL(blk_pre_runtime_resume);
3223 : :
3224 : : /**
3225 : : * blk_post_runtime_resume - Post runtime resume processing
3226 : : * @q: the queue of the device
3227 : : * @err: return value of the device's runtime_resume function
3228 : : *
3229 : : * Description:
3230 : : * Update the queue's runtime status according to the return value of the
3231 : : * device's runtime_resume function. If it is successfully resumed, process
3232 : : * the requests that are queued into the device's queue when it is resuming
3233 : : * and then mark last busy and initiate autosuspend for it.
3234 : : *
3235 : : * This function should be called near the end of the device's
3236 : : * runtime_resume callback.
3237 : : */
3238 : : void blk_post_runtime_resume(struct request_queue *q, int err)
3239 : : {
3240 : : spin_lock_irq(q->queue_lock);
3241 : : if (!err) {
3242 : : q->rpm_status = RPM_ACTIVE;
3243 : : __blk_run_queue(q);
3244 : : pm_runtime_mark_last_busy(q->dev);
3245 : : pm_request_autosuspend(q->dev);
3246 : : } else {
3247 : : q->rpm_status = RPM_SUSPENDED;
3248 : : }
3249 : : spin_unlock_irq(q->queue_lock);
3250 : : }
3251 : : EXPORT_SYMBOL(blk_post_runtime_resume);
3252 : : #endif
3253 : :
3254 : 0 : int __init blk_dev_init(void)
3255 : : {
3256 : : BUILD_BUG_ON(__REQ_NR_BITS > 8 *
3257 : : sizeof(((struct request *)0)->cmd_flags));
3258 : :
3259 : : /* used for unplugging and affects IO latency/throughput - HIGHPRI */
3260 : 0 : kblockd_workqueue = alloc_workqueue("kblockd",
3261 : : WQ_MEM_RECLAIM | WQ_HIGHPRI |
3262 : : WQ_POWER_EFFICIENT, 0);
3263 [ # # ]: 0 : if (!kblockd_workqueue)
3264 : 0 : panic("Failed to create kblockd\n");
3265 : :
3266 : 0 : request_cachep = kmem_cache_create("blkdev_requests",
3267 : : sizeof(struct request), 0, SLAB_PANIC, NULL);
3268 : :
3269 : 0 : blk_requestq_cachep = kmem_cache_create("blkdev_queue",
3270 : : sizeof(struct request_queue), 0, SLAB_PANIC, NULL);
3271 : :
3272 : 0 : return 0;
3273 : : }
|
