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>
8 * bio rewrite, highmem i/o, etc, Jens Axboe <axboe@suse.de> - may 2001
12 * This handles all read/write requests to block devices
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>
22 #include <linux/kernel_stat.h>
23 #include <linux/string.h>
24 #include <linux/init.h>
25 #include <linux/completion.h>
26 #include <linux/slab.h>
27 #include <linux/swap.h>
28 #include <linux/writeback.h>
29 #include <linux/task_io_accounting_ops.h>
30 #include <linux/fault-inject.h>
31 #include <linux/list_sort.h>
32 #include <linux/delay.h>
33 #include <linux/ratelimit.h>
34 #include <linux/pm_runtime.h>
35 #include <linux/blk-cgroup.h>
37 #define CREATE_TRACE_POINTS
38 #include <trace/events/block.h>
44 EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap);
45 EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap);
46 EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete);
47 EXPORT_TRACEPOINT_SYMBOL_GPL(block_split);
48 EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug);
50 DEFINE_IDA(blk_queue_ida);
53 * For the allocated request tables
55 struct kmem_cache *request_cachep;
58 * For queue allocation
60 struct kmem_cache *blk_requestq_cachep;
63 * Controlling structure to kblockd
65 static struct workqueue_struct *kblockd_workqueue;
67 static void blk_clear_congested(struct request_list *rl, int sync)
69 #ifdef CONFIG_CGROUP_WRITEBACK
70 clear_wb_congested(rl->blkg->wb_congested, sync);
73 * If !CGROUP_WRITEBACK, all blkg's map to bdi->wb and we shouldn't
74 * flip its congestion state for events on other blkcgs.
76 if (rl == &rl->q->root_rl)
77 clear_wb_congested(rl->q->backing_dev_info.wb.congested, sync);
81 static void blk_set_congested(struct request_list *rl, int sync)
83 #ifdef CONFIG_CGROUP_WRITEBACK
84 set_wb_congested(rl->blkg->wb_congested, sync);
86 /* see blk_clear_congested() */
87 if (rl == &rl->q->root_rl)
88 set_wb_congested(rl->q->backing_dev_info.wb.congested, sync);
92 void blk_queue_congestion_threshold(struct request_queue *q)
96 nr = q->nr_requests - (q->nr_requests / 8) + 1;
97 if (nr > q->nr_requests)
99 q->nr_congestion_on = nr;
101 nr = q->nr_requests - (q->nr_requests / 8) - (q->nr_requests / 16) - 1;
104 q->nr_congestion_off = nr;
108 * blk_get_backing_dev_info - get the address of a queue's backing_dev_info
111 * Locates the passed device's request queue and returns the address of its
112 * backing_dev_info. This function can only be called if @bdev is opened
113 * and the return value is never NULL.
115 struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev)
117 struct request_queue *q = bdev_get_queue(bdev);
119 return &q->backing_dev_info;
121 EXPORT_SYMBOL(blk_get_backing_dev_info);
123 void blk_rq_init(struct request_queue *q, struct request *rq)
125 memset(rq, 0, sizeof(*rq));
127 INIT_LIST_HEAD(&rq->queuelist);
128 INIT_LIST_HEAD(&rq->timeout_list);
131 rq->__sector = (sector_t) -1;
132 INIT_HLIST_NODE(&rq->hash);
133 RB_CLEAR_NODE(&rq->rb_node);
135 rq->cmd_len = BLK_MAX_CDB;
137 rq->start_time = jiffies;
138 set_start_time_ns(rq);
141 EXPORT_SYMBOL(blk_rq_init);
143 static void req_bio_endio(struct request *rq, struct bio *bio,
144 unsigned int nbytes, int error)
147 bio->bi_error = error;
149 if (unlikely(rq->rq_flags & RQF_QUIET))
150 bio_set_flag(bio, BIO_QUIET);
152 bio_advance(bio, nbytes);
154 /* don't actually finish bio if it's part of flush sequence */
155 if (bio->bi_iter.bi_size == 0 && !(rq->rq_flags & RQF_FLUSH_SEQ))
159 void blk_dump_rq_flags(struct request *rq, char *msg)
163 printk(KERN_INFO "%s: dev %s: type=%x, flags=%llx\n", msg,
164 rq->rq_disk ? rq->rq_disk->disk_name : "?", rq->cmd_type,
165 (unsigned long long) rq->cmd_flags);
167 printk(KERN_INFO " sector %llu, nr/cnr %u/%u\n",
168 (unsigned long long)blk_rq_pos(rq),
169 blk_rq_sectors(rq), blk_rq_cur_sectors(rq));
170 printk(KERN_INFO " bio %p, biotail %p, len %u\n",
171 rq->bio, rq->biotail, blk_rq_bytes(rq));
173 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
174 printk(KERN_INFO " cdb: ");
175 for (bit = 0; bit < BLK_MAX_CDB; bit++)
176 printk("%02x ", rq->cmd[bit]);
180 EXPORT_SYMBOL(blk_dump_rq_flags);
182 static void blk_delay_work(struct work_struct *work)
184 struct request_queue *q;
186 q = container_of(work, struct request_queue, delay_work.work);
187 spin_lock_irq(q->queue_lock);
189 spin_unlock_irq(q->queue_lock);
193 * blk_delay_queue - restart queueing after defined interval
194 * @q: The &struct request_queue in question
195 * @msecs: Delay in msecs
198 * Sometimes queueing needs to be postponed for a little while, to allow
199 * resources to come back. This function will make sure that queueing is
200 * restarted around the specified time. Queue lock must be held.
202 void blk_delay_queue(struct request_queue *q, unsigned long msecs)
204 if (likely(!blk_queue_dead(q)))
205 queue_delayed_work(kblockd_workqueue, &q->delay_work,
206 msecs_to_jiffies(msecs));
208 EXPORT_SYMBOL(blk_delay_queue);
211 * blk_start_queue_async - asynchronously restart a previously stopped queue
212 * @q: The &struct request_queue in question
215 * blk_start_queue_async() will clear the stop flag on the queue, and
216 * ensure that the request_fn for the queue is run from an async
219 void blk_start_queue_async(struct request_queue *q)
221 queue_flag_clear(QUEUE_FLAG_STOPPED, q);
222 blk_run_queue_async(q);
224 EXPORT_SYMBOL(blk_start_queue_async);
227 * blk_start_queue - restart a previously stopped queue
228 * @q: The &struct request_queue in question
231 * blk_start_queue() will clear the stop flag on the queue, and call
232 * the request_fn for the queue if it was in a stopped state when
233 * entered. Also see blk_stop_queue(). Queue lock must be held.
235 void blk_start_queue(struct request_queue *q)
237 WARN_ON(!irqs_disabled());
239 queue_flag_clear(QUEUE_FLAG_STOPPED, q);
242 EXPORT_SYMBOL(blk_start_queue);
245 * blk_stop_queue - stop a queue
246 * @q: The &struct request_queue in question
249 * The Linux block layer assumes that a block driver will consume all
250 * entries on the request queue when the request_fn strategy is called.
251 * Often this will not happen, because of hardware limitations (queue
252 * depth settings). If a device driver gets a 'queue full' response,
253 * or if it simply chooses not to queue more I/O at one point, it can
254 * call this function to prevent the request_fn from being called until
255 * the driver has signalled it's ready to go again. This happens by calling
256 * blk_start_queue() to restart queue operations. Queue lock must be held.
258 void blk_stop_queue(struct request_queue *q)
260 cancel_delayed_work(&q->delay_work);
261 queue_flag_set(QUEUE_FLAG_STOPPED, q);
263 EXPORT_SYMBOL(blk_stop_queue);
266 * blk_sync_queue - cancel any pending callbacks on a queue
270 * The block layer may perform asynchronous callback activity
271 * on a queue, such as calling the unplug function after a timeout.
272 * A block device may call blk_sync_queue to ensure that any
273 * such activity is cancelled, thus allowing it to release resources
274 * that the callbacks might use. The caller must already have made sure
275 * that its ->make_request_fn will not re-add plugging prior to calling
278 * This function does not cancel any asynchronous activity arising
279 * out of elevator or throttling code. That would require elevator_exit()
280 * and blkcg_exit_queue() to be called with queue lock initialized.
283 void blk_sync_queue(struct request_queue *q)
285 del_timer_sync(&q->timeout);
288 struct blk_mq_hw_ctx *hctx;
291 queue_for_each_hw_ctx(q, hctx, i) {
292 cancel_work_sync(&hctx->run_work);
293 cancel_delayed_work_sync(&hctx->delay_work);
296 cancel_delayed_work_sync(&q->delay_work);
299 EXPORT_SYMBOL(blk_sync_queue);
302 * __blk_run_queue_uncond - run a queue whether or not it has been stopped
303 * @q: The queue to run
306 * Invoke request handling on a queue if there are any pending requests.
307 * May be used to restart request handling after a request has completed.
308 * This variant runs the queue whether or not the queue has been
309 * stopped. Must be called with the queue lock held and interrupts
310 * disabled. See also @blk_run_queue.
312 inline void __blk_run_queue_uncond(struct request_queue *q)
314 if (unlikely(blk_queue_dead(q)))
318 * Some request_fn implementations, e.g. scsi_request_fn(), unlock
319 * the queue lock internally. As a result multiple threads may be
320 * running such a request function concurrently. Keep track of the
321 * number of active request_fn invocations such that blk_drain_queue()
322 * can wait until all these request_fn calls have finished.
324 q->request_fn_active++;
326 q->request_fn_active--;
328 EXPORT_SYMBOL_GPL(__blk_run_queue_uncond);
331 * __blk_run_queue - run a single device queue
332 * @q: The queue to run
335 * See @blk_run_queue. This variant must be called with the queue lock
336 * held and interrupts disabled.
338 void __blk_run_queue(struct request_queue *q)
340 if (unlikely(blk_queue_stopped(q)))
343 __blk_run_queue_uncond(q);
345 EXPORT_SYMBOL(__blk_run_queue);
348 * blk_run_queue_async - run a single device queue in workqueue context
349 * @q: The queue to run
352 * Tells kblockd to perform the equivalent of @blk_run_queue on behalf
353 * of us. The caller must hold the queue lock.
355 void blk_run_queue_async(struct request_queue *q)
357 if (likely(!blk_queue_stopped(q) && !blk_queue_dead(q)))
358 mod_delayed_work(kblockd_workqueue, &q->delay_work, 0);
360 EXPORT_SYMBOL(blk_run_queue_async);
363 * blk_run_queue - run a single device queue
364 * @q: The queue to run
367 * Invoke request handling on this queue, if it has pending work to do.
368 * May be used to restart queueing when a request has completed.
370 void blk_run_queue(struct request_queue *q)
374 spin_lock_irqsave(q->queue_lock, flags);
376 spin_unlock_irqrestore(q->queue_lock, flags);
378 EXPORT_SYMBOL(blk_run_queue);
380 void blk_put_queue(struct request_queue *q)
382 kobject_put(&q->kobj);
384 EXPORT_SYMBOL(blk_put_queue);
387 * __blk_drain_queue - drain requests from request_queue
389 * @drain_all: whether to drain all requests or only the ones w/ ELVPRIV
391 * Drain requests from @q. If @drain_all is set, all requests are drained.
392 * If not, only ELVPRIV requests are drained. The caller is responsible
393 * for ensuring that no new requests which need to be drained are queued.
395 static void __blk_drain_queue(struct request_queue *q, bool drain_all)
396 __releases(q->queue_lock)
397 __acquires(q->queue_lock)
401 lockdep_assert_held(q->queue_lock);
407 * The caller might be trying to drain @q before its
408 * elevator is initialized.
411 elv_drain_elevator(q);
413 blkcg_drain_queue(q);
416 * This function might be called on a queue which failed
417 * driver init after queue creation or is not yet fully
418 * active yet. Some drivers (e.g. fd and loop) get unhappy
419 * in such cases. Kick queue iff dispatch queue has
420 * something on it and @q has request_fn set.
422 if (!list_empty(&q->queue_head) && q->request_fn)
425 drain |= q->nr_rqs_elvpriv;
426 drain |= q->request_fn_active;
429 * Unfortunately, requests are queued at and tracked from
430 * multiple places and there's no single counter which can
431 * be drained. Check all the queues and counters.
434 struct blk_flush_queue *fq = blk_get_flush_queue(q, NULL);
435 drain |= !list_empty(&q->queue_head);
436 for (i = 0; i < 2; i++) {
437 drain |= q->nr_rqs[i];
438 drain |= q->in_flight[i];
440 drain |= !list_empty(&fq->flush_queue[i]);
447 spin_unlock_irq(q->queue_lock);
451 spin_lock_irq(q->queue_lock);
455 * With queue marked dead, any woken up waiter will fail the
456 * allocation path, so the wakeup chaining is lost and we're
457 * left with hung waiters. We need to wake up those waiters.
460 struct request_list *rl;
462 blk_queue_for_each_rl(rl, q)
463 for (i = 0; i < ARRAY_SIZE(rl->wait); i++)
464 wake_up_all(&rl->wait[i]);
469 * blk_queue_bypass_start - enter queue bypass mode
470 * @q: queue of interest
472 * In bypass mode, only the dispatch FIFO queue of @q is used. This
473 * function makes @q enter bypass mode and drains all requests which were
474 * throttled or issued before. On return, it's guaranteed that no request
475 * is being throttled or has ELVPRIV set and blk_queue_bypass() %true
476 * inside queue or RCU read lock.
478 void blk_queue_bypass_start(struct request_queue *q)
480 spin_lock_irq(q->queue_lock);
482 queue_flag_set(QUEUE_FLAG_BYPASS, q);
483 spin_unlock_irq(q->queue_lock);
486 * Queues start drained. Skip actual draining till init is
487 * complete. This avoids lenghty delays during queue init which
488 * can happen many times during boot.
490 if (blk_queue_init_done(q)) {
491 spin_lock_irq(q->queue_lock);
492 __blk_drain_queue(q, false);
493 spin_unlock_irq(q->queue_lock);
495 /* ensure blk_queue_bypass() is %true inside RCU read lock */
499 EXPORT_SYMBOL_GPL(blk_queue_bypass_start);
502 * blk_queue_bypass_end - leave queue bypass mode
503 * @q: queue of interest
505 * Leave bypass mode and restore the normal queueing behavior.
507 void blk_queue_bypass_end(struct request_queue *q)
509 spin_lock_irq(q->queue_lock);
510 if (!--q->bypass_depth)
511 queue_flag_clear(QUEUE_FLAG_BYPASS, q);
512 WARN_ON_ONCE(q->bypass_depth < 0);
513 spin_unlock_irq(q->queue_lock);
515 EXPORT_SYMBOL_GPL(blk_queue_bypass_end);
517 void blk_set_queue_dying(struct request_queue *q)
519 spin_lock_irq(q->queue_lock);
520 queue_flag_set(QUEUE_FLAG_DYING, q);
521 spin_unlock_irq(q->queue_lock);
524 blk_mq_wake_waiters(q);
526 struct request_list *rl;
528 blk_queue_for_each_rl(rl, q) {
530 wake_up(&rl->wait[BLK_RW_SYNC]);
531 wake_up(&rl->wait[BLK_RW_ASYNC]);
536 EXPORT_SYMBOL_GPL(blk_set_queue_dying);
539 * blk_cleanup_queue - shutdown a request queue
540 * @q: request queue to shutdown
542 * Mark @q DYING, drain all pending requests, mark @q DEAD, destroy and
543 * put it. All future requests will be failed immediately with -ENODEV.
545 void blk_cleanup_queue(struct request_queue *q)
547 spinlock_t *lock = q->queue_lock;
549 /* mark @q DYING, no new request or merges will be allowed afterwards */
550 mutex_lock(&q->sysfs_lock);
551 blk_set_queue_dying(q);
555 * A dying queue is permanently in bypass mode till released. Note
556 * that, unlike blk_queue_bypass_start(), we aren't performing
557 * synchronize_rcu() after entering bypass mode to avoid the delay
558 * as some drivers create and destroy a lot of queues while
559 * probing. This is still safe because blk_release_queue() will be
560 * called only after the queue refcnt drops to zero and nothing,
561 * RCU or not, would be traversing the queue by then.
564 queue_flag_set(QUEUE_FLAG_BYPASS, q);
566 queue_flag_set(QUEUE_FLAG_NOMERGES, q);
567 queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
568 queue_flag_set(QUEUE_FLAG_DYING, q);
569 spin_unlock_irq(lock);
570 mutex_unlock(&q->sysfs_lock);
573 * Drain all requests queued before DYING marking. Set DEAD flag to
574 * prevent that q->request_fn() gets invoked after draining finished.
579 __blk_drain_queue(q, true);
580 queue_flag_set(QUEUE_FLAG_DEAD, q);
581 spin_unlock_irq(lock);
583 /* for synchronous bio-based driver finish in-flight integrity i/o */
584 blk_flush_integrity();
586 /* @q won't process any more request, flush async actions */
587 del_timer_sync(&q->backing_dev_info.laptop_mode_wb_timer);
591 blk_mq_free_queue(q);
592 percpu_ref_exit(&q->q_usage_counter);
595 if (q->queue_lock != &q->__queue_lock)
596 q->queue_lock = &q->__queue_lock;
597 spin_unlock_irq(lock);
599 bdi_unregister(&q->backing_dev_info);
601 /* @q is and will stay empty, shutdown and put */
604 EXPORT_SYMBOL(blk_cleanup_queue);
606 /* Allocate memory local to the request queue */
607 static void *alloc_request_struct(gfp_t gfp_mask, void *data)
609 int nid = (int)(long)data;
610 return kmem_cache_alloc_node(request_cachep, gfp_mask, nid);
613 static void free_request_struct(void *element, void *unused)
615 kmem_cache_free(request_cachep, element);
618 int blk_init_rl(struct request_list *rl, struct request_queue *q,
621 if (unlikely(rl->rq_pool))
625 rl->count[BLK_RW_SYNC] = rl->count[BLK_RW_ASYNC] = 0;
626 rl->starved[BLK_RW_SYNC] = rl->starved[BLK_RW_ASYNC] = 0;
627 init_waitqueue_head(&rl->wait[BLK_RW_SYNC]);
628 init_waitqueue_head(&rl->wait[BLK_RW_ASYNC]);
630 rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ, alloc_request_struct,
632 (void *)(long)q->node, gfp_mask,
640 void blk_exit_rl(struct request_list *rl)
643 mempool_destroy(rl->rq_pool);
646 struct request_queue *blk_alloc_queue(gfp_t gfp_mask)
648 return blk_alloc_queue_node(gfp_mask, NUMA_NO_NODE);
650 EXPORT_SYMBOL(blk_alloc_queue);
652 int blk_queue_enter(struct request_queue *q, bool nowait)
657 if (percpu_ref_tryget_live(&q->q_usage_counter))
663 ret = wait_event_interruptible(q->mq_freeze_wq,
664 !atomic_read(&q->mq_freeze_depth) ||
666 if (blk_queue_dying(q))
673 void blk_queue_exit(struct request_queue *q)
675 percpu_ref_put(&q->q_usage_counter);
678 static void blk_queue_usage_counter_release(struct percpu_ref *ref)
680 struct request_queue *q =
681 container_of(ref, struct request_queue, q_usage_counter);
683 wake_up_all(&q->mq_freeze_wq);
686 static void blk_rq_timed_out_timer(unsigned long data)
688 struct request_queue *q = (struct request_queue *)data;
690 kblockd_schedule_work(&q->timeout_work);
693 struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
695 struct request_queue *q;
698 q = kmem_cache_alloc_node(blk_requestq_cachep,
699 gfp_mask | __GFP_ZERO, node_id);
703 q->id = ida_simple_get(&blk_queue_ida, 0, 0, gfp_mask);
707 q->bio_split = bioset_create(BIO_POOL_SIZE, 0);
711 q->backing_dev_info.ra_pages =
712 (VM_MAX_READAHEAD * 1024) / PAGE_SIZE;
713 q->backing_dev_info.capabilities = BDI_CAP_CGROUP_WRITEBACK;
714 q->backing_dev_info.name = "block";
717 err = bdi_init(&q->backing_dev_info);
721 setup_timer(&q->backing_dev_info.laptop_mode_wb_timer,
722 laptop_mode_timer_fn, (unsigned long) q);
723 setup_timer(&q->timeout, blk_rq_timed_out_timer, (unsigned long) q);
724 INIT_LIST_HEAD(&q->queue_head);
725 INIT_LIST_HEAD(&q->timeout_list);
726 INIT_LIST_HEAD(&q->icq_list);
727 #ifdef CONFIG_BLK_CGROUP
728 INIT_LIST_HEAD(&q->blkg_list);
730 INIT_DELAYED_WORK(&q->delay_work, blk_delay_work);
732 kobject_init(&q->kobj, &blk_queue_ktype);
734 mutex_init(&q->sysfs_lock);
735 spin_lock_init(&q->__queue_lock);
738 * By default initialize queue_lock to internal lock and driver can
739 * override it later if need be.
741 q->queue_lock = &q->__queue_lock;
744 * A queue starts its life with bypass turned on to avoid
745 * unnecessary bypass on/off overhead and nasty surprises during
746 * init. The initial bypass will be finished when the queue is
747 * registered by blk_register_queue().
750 __set_bit(QUEUE_FLAG_BYPASS, &q->queue_flags);
752 init_waitqueue_head(&q->mq_freeze_wq);
755 * Init percpu_ref in atomic mode so that it's faster to shutdown.
756 * See blk_register_queue() for details.
758 if (percpu_ref_init(&q->q_usage_counter,
759 blk_queue_usage_counter_release,
760 PERCPU_REF_INIT_ATOMIC, GFP_KERNEL))
763 if (blkcg_init_queue(q))
769 percpu_ref_exit(&q->q_usage_counter);
771 bdi_destroy(&q->backing_dev_info);
773 bioset_free(q->bio_split);
775 ida_simple_remove(&blk_queue_ida, q->id);
777 kmem_cache_free(blk_requestq_cachep, q);
780 EXPORT_SYMBOL(blk_alloc_queue_node);
783 * blk_init_queue - prepare a request queue for use with a block device
784 * @rfn: The function to be called to process requests that have been
785 * placed on the queue.
786 * @lock: Request queue spin lock
789 * If a block device wishes to use the standard request handling procedures,
790 * which sorts requests and coalesces adjacent requests, then it must
791 * call blk_init_queue(). The function @rfn will be called when there
792 * are requests on the queue that need to be processed. If the device
793 * supports plugging, then @rfn may not be called immediately when requests
794 * are available on the queue, but may be called at some time later instead.
795 * Plugged queues are generally unplugged when a buffer belonging to one
796 * of the requests on the queue is needed, or due to memory pressure.
798 * @rfn is not required, or even expected, to remove all requests off the
799 * queue, but only as many as it can handle at a time. If it does leave
800 * requests on the queue, it is responsible for arranging that the requests
801 * get dealt with eventually.
803 * The queue spin lock must be held while manipulating the requests on the
804 * request queue; this lock will be taken also from interrupt context, so irq
805 * disabling is needed for it.
807 * Function returns a pointer to the initialized request queue, or %NULL if
811 * blk_init_queue() must be paired with a blk_cleanup_queue() call
812 * when the block device is deactivated (such as at module unload).
815 struct request_queue *blk_init_queue(request_fn_proc *rfn, spinlock_t *lock)
817 return blk_init_queue_node(rfn, lock, NUMA_NO_NODE);
819 EXPORT_SYMBOL(blk_init_queue);
821 struct request_queue *
822 blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id)
824 struct request_queue *uninit_q, *q;
826 uninit_q = blk_alloc_queue_node(GFP_KERNEL, node_id);
830 q = blk_init_allocated_queue(uninit_q, rfn, lock);
832 blk_cleanup_queue(uninit_q);
836 EXPORT_SYMBOL(blk_init_queue_node);
838 static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio);
840 struct request_queue *
841 blk_init_allocated_queue(struct request_queue *q, request_fn_proc *rfn,
847 q->fq = blk_alloc_flush_queue(q, NUMA_NO_NODE, 0);
851 if (blk_init_rl(&q->root_rl, q, GFP_KERNEL))
854 INIT_WORK(&q->timeout_work, blk_timeout_work);
856 q->prep_rq_fn = NULL;
857 q->unprep_rq_fn = NULL;
858 q->queue_flags |= QUEUE_FLAG_DEFAULT;
860 /* Override internal queue lock with supplied lock pointer */
862 q->queue_lock = lock;
865 * This also sets hw/phys segments, boundary and size
867 blk_queue_make_request(q, blk_queue_bio);
869 q->sg_reserved_size = INT_MAX;
871 /* Protect q->elevator from elevator_change */
872 mutex_lock(&q->sysfs_lock);
875 if (elevator_init(q, NULL)) {
876 mutex_unlock(&q->sysfs_lock);
880 mutex_unlock(&q->sysfs_lock);
885 blk_free_flush_queue(q->fq);
889 EXPORT_SYMBOL(blk_init_allocated_queue);
891 bool blk_get_queue(struct request_queue *q)
893 if (likely(!blk_queue_dying(q))) {
900 EXPORT_SYMBOL(blk_get_queue);
902 static inline void blk_free_request(struct request_list *rl, struct request *rq)
904 if (rq->rq_flags & RQF_ELVPRIV) {
905 elv_put_request(rl->q, rq);
907 put_io_context(rq->elv.icq->ioc);
910 mempool_free(rq, rl->rq_pool);
914 * ioc_batching returns true if the ioc is a valid batching request and
915 * should be given priority access to a request.
917 static inline int ioc_batching(struct request_queue *q, struct io_context *ioc)
923 * Make sure the process is able to allocate at least 1 request
924 * even if the batch times out, otherwise we could theoretically
927 return ioc->nr_batch_requests == q->nr_batching ||
928 (ioc->nr_batch_requests > 0
929 && time_before(jiffies, ioc->last_waited + BLK_BATCH_TIME));
933 * ioc_set_batching sets ioc to be a new "batcher" if it is not one. This
934 * will cause the process to be a "batcher" on all queues in the system. This
935 * is the behaviour we want though - once it gets a wakeup it should be given
938 static void ioc_set_batching(struct request_queue *q, struct io_context *ioc)
940 if (!ioc || ioc_batching(q, ioc))
943 ioc->nr_batch_requests = q->nr_batching;
944 ioc->last_waited = jiffies;
947 static void __freed_request(struct request_list *rl, int sync)
949 struct request_queue *q = rl->q;
951 if (rl->count[sync] < queue_congestion_off_threshold(q))
952 blk_clear_congested(rl, sync);
954 if (rl->count[sync] + 1 <= q->nr_requests) {
955 if (waitqueue_active(&rl->wait[sync]))
956 wake_up(&rl->wait[sync]);
958 blk_clear_rl_full(rl, sync);
963 * A request has just been released. Account for it, update the full and
964 * congestion status, wake up any waiters. Called under q->queue_lock.
966 static void freed_request(struct request_list *rl, bool sync,
967 req_flags_t rq_flags)
969 struct request_queue *q = rl->q;
973 if (rq_flags & RQF_ELVPRIV)
976 __freed_request(rl, sync);
978 if (unlikely(rl->starved[sync ^ 1]))
979 __freed_request(rl, sync ^ 1);
982 int blk_update_nr_requests(struct request_queue *q, unsigned int nr)
984 struct request_list *rl;
985 int on_thresh, off_thresh;
987 spin_lock_irq(q->queue_lock);
989 blk_queue_congestion_threshold(q);
990 on_thresh = queue_congestion_on_threshold(q);
991 off_thresh = queue_congestion_off_threshold(q);
993 blk_queue_for_each_rl(rl, q) {
994 if (rl->count[BLK_RW_SYNC] >= on_thresh)
995 blk_set_congested(rl, BLK_RW_SYNC);
996 else if (rl->count[BLK_RW_SYNC] < off_thresh)
997 blk_clear_congested(rl, BLK_RW_SYNC);
999 if (rl->count[BLK_RW_ASYNC] >= on_thresh)
1000 blk_set_congested(rl, BLK_RW_ASYNC);
1001 else if (rl->count[BLK_RW_ASYNC] < off_thresh)
1002 blk_clear_congested(rl, BLK_RW_ASYNC);
1004 if (rl->count[BLK_RW_SYNC] >= q->nr_requests) {
1005 blk_set_rl_full(rl, BLK_RW_SYNC);
1007 blk_clear_rl_full(rl, BLK_RW_SYNC);
1008 wake_up(&rl->wait[BLK_RW_SYNC]);
1011 if (rl->count[BLK_RW_ASYNC] >= q->nr_requests) {
1012 blk_set_rl_full(rl, BLK_RW_ASYNC);
1014 blk_clear_rl_full(rl, BLK_RW_ASYNC);
1015 wake_up(&rl->wait[BLK_RW_ASYNC]);
1019 spin_unlock_irq(q->queue_lock);
1024 * Determine if elevator data should be initialized when allocating the
1025 * request associated with @bio.
1027 static bool blk_rq_should_init_elevator(struct bio *bio)
1033 * Flush requests do not use the elevator so skip initialization.
1034 * This allows a request to share the flush and elevator data.
1036 if (bio->bi_opf & (REQ_PREFLUSH | REQ_FUA))
1043 * rq_ioc - determine io_context for request allocation
1044 * @bio: request being allocated is for this bio (can be %NULL)
1046 * Determine io_context to use for request allocation for @bio. May return
1047 * %NULL if %current->io_context doesn't exist.
1049 static struct io_context *rq_ioc(struct bio *bio)
1051 #ifdef CONFIG_BLK_CGROUP
1052 if (bio && bio->bi_ioc)
1055 return current->io_context;
1059 * __get_request - get a free request
1060 * @rl: request list to allocate from
1061 * @op: operation and flags
1062 * @bio: bio to allocate request for (can be %NULL)
1063 * @gfp_mask: allocation mask
1065 * Get a free request from @q. This function may fail under memory
1066 * pressure or if @q is dead.
1068 * Must be called with @q->queue_lock held and,
1069 * Returns ERR_PTR on failure, with @q->queue_lock held.
1070 * Returns request pointer on success, with @q->queue_lock *not held*.
1072 static struct request *__get_request(struct request_list *rl, unsigned int op,
1073 struct bio *bio, gfp_t gfp_mask)
1075 struct request_queue *q = rl->q;
1077 struct elevator_type *et = q->elevator->type;
1078 struct io_context *ioc = rq_ioc(bio);
1079 struct io_cq *icq = NULL;
1080 const bool is_sync = op_is_sync(op);
1082 req_flags_t rq_flags = RQF_ALLOCED;
1084 if (unlikely(blk_queue_dying(q)))
1085 return ERR_PTR(-ENODEV);
1087 may_queue = elv_may_queue(q, op);
1088 if (may_queue == ELV_MQUEUE_NO)
1091 if (rl->count[is_sync]+1 >= queue_congestion_on_threshold(q)) {
1092 if (rl->count[is_sync]+1 >= q->nr_requests) {
1094 * The queue will fill after this allocation, so set
1095 * it as full, and mark this process as "batching".
1096 * This process will be allowed to complete a batch of
1097 * requests, others will be blocked.
1099 if (!blk_rl_full(rl, is_sync)) {
1100 ioc_set_batching(q, ioc);
1101 blk_set_rl_full(rl, is_sync);
1103 if (may_queue != ELV_MQUEUE_MUST
1104 && !ioc_batching(q, ioc)) {
1106 * The queue is full and the allocating
1107 * process is not a "batcher", and not
1108 * exempted by the IO scheduler
1110 return ERR_PTR(-ENOMEM);
1114 blk_set_congested(rl, is_sync);
1118 * Only allow batching queuers to allocate up to 50% over the defined
1119 * limit of requests, otherwise we could have thousands of requests
1120 * allocated with any setting of ->nr_requests
1122 if (rl->count[is_sync] >= (3 * q->nr_requests / 2))
1123 return ERR_PTR(-ENOMEM);
1125 q->nr_rqs[is_sync]++;
1126 rl->count[is_sync]++;
1127 rl->starved[is_sync] = 0;
1130 * Decide whether the new request will be managed by elevator. If
1131 * so, mark @rq_flags and increment elvpriv. Non-zero elvpriv will
1132 * prevent the current elevator from being destroyed until the new
1133 * request is freed. This guarantees icq's won't be destroyed and
1134 * makes creating new ones safe.
1136 * Also, lookup icq while holding queue_lock. If it doesn't exist,
1137 * it will be created after releasing queue_lock.
1139 if (blk_rq_should_init_elevator(bio) && !blk_queue_bypass(q)) {
1140 rq_flags |= RQF_ELVPRIV;
1141 q->nr_rqs_elvpriv++;
1142 if (et->icq_cache && ioc)
1143 icq = ioc_lookup_icq(ioc, q);
1146 if (blk_queue_io_stat(q))
1147 rq_flags |= RQF_IO_STAT;
1148 spin_unlock_irq(q->queue_lock);
1150 /* allocate and init request */
1151 rq = mempool_alloc(rl->rq_pool, gfp_mask);
1156 blk_rq_set_rl(rq, rl);
1158 rq->rq_flags = rq_flags;
1161 if (rq_flags & RQF_ELVPRIV) {
1162 if (unlikely(et->icq_cache && !icq)) {
1164 icq = ioc_create_icq(ioc, q, gfp_mask);
1170 if (unlikely(elv_set_request(q, rq, bio, gfp_mask)))
1173 /* @rq->elv.icq holds io_context until @rq is freed */
1175 get_io_context(icq->ioc);
1179 * ioc may be NULL here, and ioc_batching will be false. That's
1180 * OK, if the queue is under the request limit then requests need
1181 * not count toward the nr_batch_requests limit. There will always
1182 * be some limit enforced by BLK_BATCH_TIME.
1184 if (ioc_batching(q, ioc))
1185 ioc->nr_batch_requests--;
1187 trace_block_getrq(q, bio, op);
1192 * elvpriv init failed. ioc, icq and elvpriv aren't mempool backed
1193 * and may fail indefinitely under memory pressure and thus
1194 * shouldn't stall IO. Treat this request as !elvpriv. This will
1195 * disturb iosched and blkcg but weird is bettern than dead.
1197 printk_ratelimited(KERN_WARNING "%s: dev %s: request aux data allocation failed, iosched may be disturbed\n",
1198 __func__, dev_name(q->backing_dev_info.dev));
1200 rq->rq_flags &= ~RQF_ELVPRIV;
1203 spin_lock_irq(q->queue_lock);
1204 q->nr_rqs_elvpriv--;
1205 spin_unlock_irq(q->queue_lock);
1210 * Allocation failed presumably due to memory. Undo anything we
1211 * might have messed up.
1213 * Allocating task should really be put onto the front of the wait
1214 * queue, but this is pretty rare.
1216 spin_lock_irq(q->queue_lock);
1217 freed_request(rl, is_sync, rq_flags);
1220 * in the very unlikely event that allocation failed and no
1221 * requests for this direction was pending, mark us starved so that
1222 * freeing of a request in the other direction will notice
1223 * us. another possible fix would be to split the rq mempool into
1227 if (unlikely(rl->count[is_sync] == 0))
1228 rl->starved[is_sync] = 1;
1229 return ERR_PTR(-ENOMEM);
1233 * get_request - get a free request
1234 * @q: request_queue to allocate request from
1235 * @op: operation and flags
1236 * @bio: bio to allocate request for (can be %NULL)
1237 * @gfp_mask: allocation mask
1239 * Get a free request from @q. If %__GFP_DIRECT_RECLAIM is set in @gfp_mask,
1240 * this function keeps retrying under memory pressure and fails iff @q is dead.
1242 * Must be called with @q->queue_lock held and,
1243 * Returns ERR_PTR on failure, with @q->queue_lock held.
1244 * Returns request pointer on success, with @q->queue_lock *not held*.
1246 static struct request *get_request(struct request_queue *q, unsigned int op,
1247 struct bio *bio, gfp_t gfp_mask)
1249 const bool is_sync = op_is_sync(op);
1251 struct request_list *rl;
1254 rl = blk_get_rl(q, bio); /* transferred to @rq on success */
1256 rq = __get_request(rl, op, bio, gfp_mask);
1260 if (!gfpflags_allow_blocking(gfp_mask) || unlikely(blk_queue_dying(q))) {
1265 /* wait on @rl and retry */
1266 prepare_to_wait_exclusive(&rl->wait[is_sync], &wait,
1267 TASK_UNINTERRUPTIBLE);
1269 trace_block_sleeprq(q, bio, op);
1271 spin_unlock_irq(q->queue_lock);
1275 * After sleeping, we become a "batching" process and will be able
1276 * to allocate at least one request, and up to a big batch of them
1277 * for a small period time. See ioc_batching, ioc_set_batching
1279 ioc_set_batching(q, current->io_context);
1281 spin_lock_irq(q->queue_lock);
1282 finish_wait(&rl->wait[is_sync], &wait);
1287 static struct request *blk_old_get_request(struct request_queue *q, int rw,
1292 BUG_ON(rw != READ && rw != WRITE);
1294 /* create ioc upfront */
1295 create_io_context(gfp_mask, q->node);
1297 spin_lock_irq(q->queue_lock);
1298 rq = get_request(q, rw, NULL, gfp_mask);
1300 spin_unlock_irq(q->queue_lock);
1304 /* q->queue_lock is unlocked at this point */
1306 rq->__sector = (sector_t) -1;
1307 rq->bio = rq->biotail = NULL;
1311 struct request *blk_get_request(struct request_queue *q, int rw, gfp_t gfp_mask)
1314 return blk_mq_alloc_request(q, rw,
1315 (gfp_mask & __GFP_DIRECT_RECLAIM) ?
1316 0 : BLK_MQ_REQ_NOWAIT);
1318 return blk_old_get_request(q, rw, gfp_mask);
1320 EXPORT_SYMBOL(blk_get_request);
1323 * blk_rq_set_block_pc - initialize a request to type BLOCK_PC
1324 * @rq: request to be initialized
1327 void blk_rq_set_block_pc(struct request *rq)
1329 rq->cmd_type = REQ_TYPE_BLOCK_PC;
1330 memset(rq->__cmd, 0, sizeof(rq->__cmd));
1332 EXPORT_SYMBOL(blk_rq_set_block_pc);
1335 * blk_requeue_request - put a request back on queue
1336 * @q: request queue where request should be inserted
1337 * @rq: request to be inserted
1340 * Drivers often keep queueing requests until the hardware cannot accept
1341 * more, when that condition happens we need to put the request back
1342 * on the queue. Must be called with queue lock held.
1344 void blk_requeue_request(struct request_queue *q, struct request *rq)
1346 blk_delete_timer(rq);
1347 blk_clear_rq_complete(rq);
1348 trace_block_rq_requeue(q, rq);
1349 wbt_requeue(q->rq_wb, &rq->issue_stat);
1351 if (rq->rq_flags & RQF_QUEUED)
1352 blk_queue_end_tag(q, rq);
1354 BUG_ON(blk_queued_rq(rq));
1356 elv_requeue_request(q, rq);
1358 EXPORT_SYMBOL(blk_requeue_request);
1360 static void add_acct_request(struct request_queue *q, struct request *rq,
1363 blk_account_io_start(rq, true);
1364 __elv_add_request(q, rq, where);
1367 static void part_round_stats_single(int cpu, struct hd_struct *part,
1372 if (now == part->stamp)
1375 inflight = part_in_flight(part);
1377 __part_stat_add(cpu, part, time_in_queue,
1378 inflight * (now - part->stamp));
1379 __part_stat_add(cpu, part, io_ticks, (now - part->stamp));
1385 * part_round_stats() - Round off the performance stats on a struct disk_stats.
1386 * @cpu: cpu number for stats access
1387 * @part: target partition
1389 * The average IO queue length and utilisation statistics are maintained
1390 * by observing the current state of the queue length and the amount of
1391 * time it has been in this state for.
1393 * Normally, that accounting is done on IO completion, but that can result
1394 * in more than a second's worth of IO being accounted for within any one
1395 * second, leading to >100% utilisation. To deal with that, we call this
1396 * function to do a round-off before returning the results when reading
1397 * /proc/diskstats. This accounts immediately for all queue usage up to
1398 * the current jiffies and restarts the counters again.
1400 void part_round_stats(int cpu, struct hd_struct *part)
1402 unsigned long now = jiffies;
1405 part_round_stats_single(cpu, &part_to_disk(part)->part0, now);
1406 part_round_stats_single(cpu, part, now);
1408 EXPORT_SYMBOL_GPL(part_round_stats);
1411 static void blk_pm_put_request(struct request *rq)
1413 if (rq->q->dev && !(rq->rq_flags & RQF_PM) && !--rq->q->nr_pending)
1414 pm_runtime_mark_last_busy(rq->q->dev);
1417 static inline void blk_pm_put_request(struct request *rq) {}
1421 * queue lock must be held
1423 void __blk_put_request(struct request_queue *q, struct request *req)
1425 req_flags_t rq_flags = req->rq_flags;
1431 blk_mq_free_request(req);
1435 blk_pm_put_request(req);
1437 elv_completed_request(q, req);
1439 /* this is a bio leak */
1440 WARN_ON(req->bio != NULL);
1442 wbt_done(q->rq_wb, &req->issue_stat);
1445 * Request may not have originated from ll_rw_blk. if not,
1446 * it didn't come out of our reserved rq pools
1448 if (rq_flags & RQF_ALLOCED) {
1449 struct request_list *rl = blk_rq_rl(req);
1450 bool sync = op_is_sync(req->cmd_flags);
1452 BUG_ON(!list_empty(&req->queuelist));
1453 BUG_ON(ELV_ON_HASH(req));
1455 blk_free_request(rl, req);
1456 freed_request(rl, sync, rq_flags);
1460 EXPORT_SYMBOL_GPL(__blk_put_request);
1462 void blk_put_request(struct request *req)
1464 struct request_queue *q = req->q;
1467 blk_mq_free_request(req);
1469 unsigned long flags;
1471 spin_lock_irqsave(q->queue_lock, flags);
1472 __blk_put_request(q, req);
1473 spin_unlock_irqrestore(q->queue_lock, flags);
1476 EXPORT_SYMBOL(blk_put_request);
1479 * blk_add_request_payload - add a payload to a request
1480 * @rq: request to update
1481 * @page: page backing the payload
1482 * @offset: offset in page
1483 * @len: length of the payload.
1485 * This allows to later add a payload to an already submitted request by
1486 * a block driver. The driver needs to take care of freeing the payload
1489 * Note that this is a quite horrible hack and nothing but handling of
1490 * discard requests should ever use it.
1492 void blk_add_request_payload(struct request *rq, struct page *page,
1493 int offset, unsigned int len)
1495 struct bio *bio = rq->bio;
1497 bio->bi_io_vec->bv_page = page;
1498 bio->bi_io_vec->bv_offset = offset;
1499 bio->bi_io_vec->bv_len = len;
1501 bio->bi_iter.bi_size = len;
1503 bio->bi_phys_segments = 1;
1505 rq->__data_len = rq->resid_len = len;
1506 rq->nr_phys_segments = 1;
1508 EXPORT_SYMBOL_GPL(blk_add_request_payload);
1510 bool bio_attempt_back_merge(struct request_queue *q, struct request *req,
1513 const int ff = bio->bi_opf & REQ_FAILFAST_MASK;
1515 if (!ll_back_merge_fn(q, req, bio))
1518 trace_block_bio_backmerge(q, req, bio);
1520 if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff)
1521 blk_rq_set_mixed_merge(req);
1523 req->biotail->bi_next = bio;
1525 req->__data_len += bio->bi_iter.bi_size;
1526 req->ioprio = ioprio_best(req->ioprio, bio_prio(bio));
1528 blk_account_io_start(req, false);
1532 bool bio_attempt_front_merge(struct request_queue *q, struct request *req,
1535 const int ff = bio->bi_opf & REQ_FAILFAST_MASK;
1537 if (!ll_front_merge_fn(q, req, bio))
1540 trace_block_bio_frontmerge(q, req, bio);
1542 if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff)
1543 blk_rq_set_mixed_merge(req);
1545 bio->bi_next = req->bio;
1548 req->__sector = bio->bi_iter.bi_sector;
1549 req->__data_len += bio->bi_iter.bi_size;
1550 req->ioprio = ioprio_best(req->ioprio, bio_prio(bio));
1552 blk_account_io_start(req, false);
1557 * blk_attempt_plug_merge - try to merge with %current's plugged list
1558 * @q: request_queue new bio is being queued at
1559 * @bio: new bio being queued
1560 * @request_count: out parameter for number of traversed plugged requests
1561 * @same_queue_rq: pointer to &struct request that gets filled in when
1562 * another request associated with @q is found on the plug list
1563 * (optional, may be %NULL)
1565 * Determine whether @bio being queued on @q can be merged with a request
1566 * on %current's plugged list. Returns %true if merge was successful,
1569 * Plugging coalesces IOs from the same issuer for the same purpose without
1570 * going through @q->queue_lock. As such it's more of an issuing mechanism
1571 * than scheduling, and the request, while may have elvpriv data, is not
1572 * added on the elevator at this point. In addition, we don't have
1573 * reliable access to the elevator outside queue lock. Only check basic
1574 * merging parameters without querying the elevator.
1576 * Caller must ensure !blk_queue_nomerges(q) beforehand.
1578 bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
1579 unsigned int *request_count,
1580 struct request **same_queue_rq)
1582 struct blk_plug *plug;
1585 struct list_head *plug_list;
1587 plug = current->plug;
1593 plug_list = &plug->mq_list;
1595 plug_list = &plug->list;
1597 list_for_each_entry_reverse(rq, plug_list, queuelist) {
1603 * Only blk-mq multiple hardware queues case checks the
1604 * rq in the same queue, there should be only one such
1608 *same_queue_rq = rq;
1611 if (rq->q != q || !blk_rq_merge_ok(rq, bio))
1614 el_ret = blk_try_merge(rq, bio);
1615 if (el_ret == ELEVATOR_BACK_MERGE) {
1616 ret = bio_attempt_back_merge(q, rq, bio);
1619 } else if (el_ret == ELEVATOR_FRONT_MERGE) {
1620 ret = bio_attempt_front_merge(q, rq, bio);
1629 unsigned int blk_plug_queued_count(struct request_queue *q)
1631 struct blk_plug *plug;
1633 struct list_head *plug_list;
1634 unsigned int ret = 0;
1636 plug = current->plug;
1641 plug_list = &plug->mq_list;
1643 plug_list = &plug->list;
1645 list_for_each_entry(rq, plug_list, queuelist) {
1653 void init_request_from_bio(struct request *req, struct bio *bio)
1655 req->cmd_type = REQ_TYPE_FS;
1656 if (bio->bi_opf & REQ_RAHEAD)
1657 req->cmd_flags |= REQ_FAILFAST_MASK;
1660 req->__sector = bio->bi_iter.bi_sector;
1661 req->ioprio = bio_prio(bio);
1662 blk_rq_bio_prep(req->q, req, bio);
1665 static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio)
1667 struct blk_plug *plug;
1668 int el_ret, where = ELEVATOR_INSERT_SORT;
1669 struct request *req;
1670 unsigned int request_count = 0;
1671 unsigned int wb_acct;
1674 * low level driver can indicate that it wants pages above a
1675 * certain limit bounced to low memory (ie for highmem, or even
1676 * ISA dma in theory)
1678 blk_queue_bounce(q, &bio);
1680 blk_queue_split(q, &bio, q->bio_split);
1682 if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) {
1683 bio->bi_error = -EIO;
1685 return BLK_QC_T_NONE;
1688 if (bio->bi_opf & (REQ_PREFLUSH | REQ_FUA)) {
1689 spin_lock_irq(q->queue_lock);
1690 where = ELEVATOR_INSERT_FLUSH;
1695 * Check if we can merge with the plugged list before grabbing
1698 if (!blk_queue_nomerges(q)) {
1699 if (blk_attempt_plug_merge(q, bio, &request_count, NULL))
1700 return BLK_QC_T_NONE;
1702 request_count = blk_plug_queued_count(q);
1704 spin_lock_irq(q->queue_lock);
1706 el_ret = elv_merge(q, &req, bio);
1707 if (el_ret == ELEVATOR_BACK_MERGE) {
1708 if (bio_attempt_back_merge(q, req, bio)) {
1709 elv_bio_merged(q, req, bio);
1710 if (!attempt_back_merge(q, req))
1711 elv_merged_request(q, req, el_ret);
1714 } else if (el_ret == ELEVATOR_FRONT_MERGE) {
1715 if (bio_attempt_front_merge(q, req, bio)) {
1716 elv_bio_merged(q, req, bio);
1717 if (!attempt_front_merge(q, req))
1718 elv_merged_request(q, req, el_ret);
1724 wb_acct = wbt_wait(q->rq_wb, bio, q->queue_lock);
1727 * Grab a free request. This is might sleep but can not fail.
1728 * Returns with the queue unlocked.
1730 req = get_request(q, bio->bi_opf, bio, GFP_NOIO);
1732 __wbt_done(q->rq_wb, wb_acct);
1733 bio->bi_error = PTR_ERR(req);
1738 wbt_track(&req->issue_stat, wb_acct);
1741 * After dropping the lock and possibly sleeping here, our request
1742 * may now be mergeable after it had proven unmergeable (above).
1743 * We don't worry about that case for efficiency. It won't happen
1744 * often, and the elevators are able to handle it.
1746 init_request_from_bio(req, bio);
1748 if (test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags))
1749 req->cpu = raw_smp_processor_id();
1751 plug = current->plug;
1754 * If this is the first request added after a plug, fire
1757 * @request_count may become stale because of schedule
1758 * out, so check plug list again.
1760 if (!request_count || list_empty(&plug->list))
1761 trace_block_plug(q);
1763 struct request *last = list_entry_rq(plug->list.prev);
1764 if (request_count >= BLK_MAX_REQUEST_COUNT ||
1765 blk_rq_bytes(last) >= BLK_PLUG_FLUSH_SIZE) {
1766 blk_flush_plug_list(plug, false);
1767 trace_block_plug(q);
1770 list_add_tail(&req->queuelist, &plug->list);
1771 blk_account_io_start(req, true);
1773 spin_lock_irq(q->queue_lock);
1774 add_acct_request(q, req, where);
1777 spin_unlock_irq(q->queue_lock);
1780 return BLK_QC_T_NONE;
1784 * If bio->bi_dev is a partition, remap the location
1786 static inline void blk_partition_remap(struct bio *bio)
1788 struct block_device *bdev = bio->bi_bdev;
1791 * Zone reset does not include bi_size so bio_sectors() is always 0.
1792 * Include a test for the reset op code and perform the remap if needed.
1794 if (bdev != bdev->bd_contains &&
1795 (bio_sectors(bio) || bio_op(bio) == REQ_OP_ZONE_RESET)) {
1796 struct hd_struct *p = bdev->bd_part;
1798 bio->bi_iter.bi_sector += p->start_sect;
1799 bio->bi_bdev = bdev->bd_contains;
1801 trace_block_bio_remap(bdev_get_queue(bio->bi_bdev), bio,
1803 bio->bi_iter.bi_sector - p->start_sect);
1807 static void handle_bad_sector(struct bio *bio)
1809 char b[BDEVNAME_SIZE];
1811 printk(KERN_INFO "attempt to access beyond end of device\n");
1812 printk(KERN_INFO "%s: rw=%d, want=%Lu, limit=%Lu\n",
1813 bdevname(bio->bi_bdev, b),
1815 (unsigned long long)bio_end_sector(bio),
1816 (long long)(i_size_read(bio->bi_bdev->bd_inode) >> 9));
1819 #ifdef CONFIG_FAIL_MAKE_REQUEST
1821 static DECLARE_FAULT_ATTR(fail_make_request);
1823 static int __init setup_fail_make_request(char *str)
1825 return setup_fault_attr(&fail_make_request, str);
1827 __setup("fail_make_request=", setup_fail_make_request);
1829 static bool should_fail_request(struct hd_struct *part, unsigned int bytes)
1831 return part->make_it_fail && should_fail(&fail_make_request, bytes);
1834 static int __init fail_make_request_debugfs(void)
1836 struct dentry *dir = fault_create_debugfs_attr("fail_make_request",
1837 NULL, &fail_make_request);
1839 return PTR_ERR_OR_ZERO(dir);
1842 late_initcall(fail_make_request_debugfs);
1844 #else /* CONFIG_FAIL_MAKE_REQUEST */
1846 static inline bool should_fail_request(struct hd_struct *part,
1852 #endif /* CONFIG_FAIL_MAKE_REQUEST */
1855 * Check whether this bio extends beyond the end of the device.
1857 static inline int bio_check_eod(struct bio *bio, unsigned int nr_sectors)
1864 /* Test device or partition size, when known. */
1865 maxsector = i_size_read(bio->bi_bdev->bd_inode) >> 9;
1867 sector_t sector = bio->bi_iter.bi_sector;
1869 if (maxsector < nr_sectors || maxsector - nr_sectors < sector) {
1871 * This may well happen - the kernel calls bread()
1872 * without checking the size of the device, e.g., when
1873 * mounting a device.
1875 handle_bad_sector(bio);
1883 static noinline_for_stack bool
1884 generic_make_request_checks(struct bio *bio)
1886 struct request_queue *q;
1887 int nr_sectors = bio_sectors(bio);
1889 char b[BDEVNAME_SIZE];
1890 struct hd_struct *part;
1894 if (bio_check_eod(bio, nr_sectors))
1897 q = bdev_get_queue(bio->bi_bdev);
1900 "generic_make_request: Trying to access "
1901 "nonexistent block-device %s (%Lu)\n",
1902 bdevname(bio->bi_bdev, b),
1903 (long long) bio->bi_iter.bi_sector);
1907 part = bio->bi_bdev->bd_part;
1908 if (should_fail_request(part, bio->bi_iter.bi_size) ||
1909 should_fail_request(&part_to_disk(part)->part0,
1910 bio->bi_iter.bi_size))
1914 * If this device has partitions, remap block n
1915 * of partition p to block n+start(p) of the disk.
1917 blk_partition_remap(bio);
1919 if (bio_check_eod(bio, nr_sectors))
1923 * Filter flush bio's early so that make_request based
1924 * drivers without flush support don't have to worry
1927 if ((bio->bi_opf & (REQ_PREFLUSH | REQ_FUA)) &&
1928 !test_bit(QUEUE_FLAG_WC, &q->queue_flags)) {
1929 bio->bi_opf &= ~(REQ_PREFLUSH | REQ_FUA);
1936 switch (bio_op(bio)) {
1937 case REQ_OP_DISCARD:
1938 if (!blk_queue_discard(q))
1941 case REQ_OP_SECURE_ERASE:
1942 if (!blk_queue_secure_erase(q))
1945 case REQ_OP_WRITE_SAME:
1946 if (!bdev_write_same(bio->bi_bdev))
1948 case REQ_OP_ZONE_REPORT:
1949 case REQ_OP_ZONE_RESET:
1950 if (!bdev_is_zoned(bio->bi_bdev))
1958 * Various block parts want %current->io_context and lazy ioc
1959 * allocation ends up trading a lot of pain for a small amount of
1960 * memory. Just allocate it upfront. This may fail and block
1961 * layer knows how to live with it.
1963 create_io_context(GFP_ATOMIC, q->node);
1965 if (!blkcg_bio_issue_check(q, bio))
1968 trace_block_bio_queue(q, bio);
1974 bio->bi_error = err;
1980 * generic_make_request - hand a buffer to its device driver for I/O
1981 * @bio: The bio describing the location in memory and on the device.
1983 * generic_make_request() is used to make I/O requests of block
1984 * devices. It is passed a &struct bio, which describes the I/O that needs
1987 * generic_make_request() does not return any status. The
1988 * success/failure status of the request, along with notification of
1989 * completion, is delivered asynchronously through the bio->bi_end_io
1990 * function described (one day) else where.
1992 * The caller of generic_make_request must make sure that bi_io_vec
1993 * are set to describe the memory buffer, and that bi_dev and bi_sector are
1994 * set to describe the device address, and the
1995 * bi_end_io and optionally bi_private are set to describe how
1996 * completion notification should be signaled.
1998 * generic_make_request and the drivers it calls may use bi_next if this
1999 * bio happens to be merged with someone else, and may resubmit the bio to
2000 * a lower device by calling into generic_make_request recursively, which
2001 * means the bio should NOT be touched after the call to ->make_request_fn.
2003 blk_qc_t generic_make_request(struct bio *bio)
2005 struct bio_list bio_list_on_stack;
2006 blk_qc_t ret = BLK_QC_T_NONE;
2008 if (!generic_make_request_checks(bio))
2012 * We only want one ->make_request_fn to be active at a time, else
2013 * stack usage with stacked devices could be a problem. So use
2014 * current->bio_list to keep a list of requests submited by a
2015 * make_request_fn function. current->bio_list is also used as a
2016 * flag to say if generic_make_request is currently active in this
2017 * task or not. If it is NULL, then no make_request is active. If
2018 * it is non-NULL, then a make_request is active, and new requests
2019 * should be added at the tail
2021 if (current->bio_list) {
2022 bio_list_add(current->bio_list, bio);
2026 /* following loop may be a bit non-obvious, and so deserves some
2028 * Before entering the loop, bio->bi_next is NULL (as all callers
2029 * ensure that) so we have a list with a single bio.
2030 * We pretend that we have just taken it off a longer list, so
2031 * we assign bio_list to a pointer to the bio_list_on_stack,
2032 * thus initialising the bio_list of new bios to be
2033 * added. ->make_request() may indeed add some more bios
2034 * through a recursive call to generic_make_request. If it
2035 * did, we find a non-NULL value in bio_list and re-enter the loop
2036 * from the top. In this case we really did just take the bio
2037 * of the top of the list (no pretending) and so remove it from
2038 * bio_list, and call into ->make_request() again.
2040 BUG_ON(bio->bi_next);
2041 bio_list_init(&bio_list_on_stack);
2042 current->bio_list = &bio_list_on_stack;
2044 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
2046 if (likely(blk_queue_enter(q, false) == 0)) {
2047 ret = q->make_request_fn(q, bio);
2051 bio = bio_list_pop(current->bio_list);
2053 struct bio *bio_next = bio_list_pop(current->bio_list);
2059 current->bio_list = NULL; /* deactivate */
2064 EXPORT_SYMBOL(generic_make_request);
2067 * submit_bio - submit a bio to the block device layer for I/O
2068 * @bio: The &struct bio which describes the I/O
2070 * submit_bio() is very similar in purpose to generic_make_request(), and
2071 * uses that function to do most of the work. Both are fairly rough
2072 * interfaces; @bio must be presetup and ready for I/O.
2075 blk_qc_t submit_bio(struct bio *bio)
2078 * If it's a regular read/write or a barrier with data attached,
2079 * go through the normal accounting stuff before submission.
2081 if (bio_has_data(bio)) {
2084 if (unlikely(bio_op(bio) == REQ_OP_WRITE_SAME))
2085 count = bdev_logical_block_size(bio->bi_bdev) >> 9;
2087 count = bio_sectors(bio);
2089 if (op_is_write(bio_op(bio))) {
2090 count_vm_events(PGPGOUT, count);
2092 task_io_account_read(bio->bi_iter.bi_size);
2093 count_vm_events(PGPGIN, count);
2096 if (unlikely(block_dump)) {
2097 char b[BDEVNAME_SIZE];
2098 printk(KERN_DEBUG "%s(%d): %s block %Lu on %s (%u sectors)\n",
2099 current->comm, task_pid_nr(current),
2100 op_is_write(bio_op(bio)) ? "WRITE" : "READ",
2101 (unsigned long long)bio->bi_iter.bi_sector,
2102 bdevname(bio->bi_bdev, b),
2107 return generic_make_request(bio);
2109 EXPORT_SYMBOL(submit_bio);
2112 * blk_cloned_rq_check_limits - Helper function to check a cloned request
2113 * for new the queue limits
2115 * @rq: the request being checked
2118 * @rq may have been made based on weaker limitations of upper-level queues
2119 * in request stacking drivers, and it may violate the limitation of @q.
2120 * Since the block layer and the underlying device driver trust @rq
2121 * after it is inserted to @q, it should be checked against @q before
2122 * the insertion using this generic function.
2124 * Request stacking drivers like request-based dm may change the queue
2125 * limits when retrying requests on other queues. Those requests need
2126 * to be checked against the new queue limits again during dispatch.
2128 static int blk_cloned_rq_check_limits(struct request_queue *q,
2131 if (blk_rq_sectors(rq) > blk_queue_get_max_sectors(q, req_op(rq))) {
2132 printk(KERN_ERR "%s: over max size limit.\n", __func__);
2137 * queue's settings related to segment counting like q->bounce_pfn
2138 * may differ from that of other stacking queues.
2139 * Recalculate it to check the request correctly on this queue's
2142 blk_recalc_rq_segments(rq);
2143 if (rq->nr_phys_segments > queue_max_segments(q)) {
2144 printk(KERN_ERR "%s: over max segments limit.\n", __func__);
2152 * blk_insert_cloned_request - Helper for stacking drivers to submit a request
2153 * @q: the queue to submit the request
2154 * @rq: the request being queued
2156 int blk_insert_cloned_request(struct request_queue *q, struct request *rq)
2158 unsigned long flags;
2159 int where = ELEVATOR_INSERT_BACK;
2161 if (blk_cloned_rq_check_limits(q, rq))
2165 should_fail_request(&rq->rq_disk->part0, blk_rq_bytes(rq)))
2169 if (blk_queue_io_stat(q))
2170 blk_account_io_start(rq, true);
2171 blk_mq_insert_request(rq, false, true, false);
2175 spin_lock_irqsave(q->queue_lock, flags);
2176 if (unlikely(blk_queue_dying(q))) {
2177 spin_unlock_irqrestore(q->queue_lock, flags);
2182 * Submitting request must be dequeued before calling this function
2183 * because it will be linked to another request_queue
2185 BUG_ON(blk_queued_rq(rq));
2187 if (rq->cmd_flags & (REQ_PREFLUSH | REQ_FUA))
2188 where = ELEVATOR_INSERT_FLUSH;
2190 add_acct_request(q, rq, where);
2191 if (where == ELEVATOR_INSERT_FLUSH)
2193 spin_unlock_irqrestore(q->queue_lock, flags);
2197 EXPORT_SYMBOL_GPL(blk_insert_cloned_request);
2200 * blk_rq_err_bytes - determine number of bytes till the next failure boundary
2201 * @rq: request to examine
2204 * A request could be merge of IOs which require different failure
2205 * handling. This function determines the number of bytes which
2206 * can be failed from the beginning of the request without
2207 * crossing into area which need to be retried further.
2210 * The number of bytes to fail.
2213 * queue_lock must be held.
2215 unsigned int blk_rq_err_bytes(const struct request *rq)
2217 unsigned int ff = rq->cmd_flags & REQ_FAILFAST_MASK;
2218 unsigned int bytes = 0;
2221 if (!(rq->rq_flags & RQF_MIXED_MERGE))
2222 return blk_rq_bytes(rq);
2225 * Currently the only 'mixing' which can happen is between
2226 * different fastfail types. We can safely fail portions
2227 * which have all the failfast bits that the first one has -
2228 * the ones which are at least as eager to fail as the first
2231 for (bio = rq->bio; bio; bio = bio->bi_next) {
2232 if ((bio->bi_opf & ff) != ff)
2234 bytes += bio->bi_iter.bi_size;
2237 /* this could lead to infinite loop */
2238 BUG_ON(blk_rq_bytes(rq) && !bytes);
2241 EXPORT_SYMBOL_GPL(blk_rq_err_bytes);
2243 void blk_account_io_completion(struct request *req, unsigned int bytes)
2245 if (blk_do_io_stat(req)) {
2246 const int rw = rq_data_dir(req);
2247 struct hd_struct *part;
2250 cpu = part_stat_lock();
2252 part_stat_add(cpu, part, sectors[rw], bytes >> 9);
2257 void blk_account_io_done(struct request *req)
2260 * Account IO completion. flush_rq isn't accounted as a
2261 * normal IO on queueing nor completion. Accounting the
2262 * containing request is enough.
2264 if (blk_do_io_stat(req) && !(req->rq_flags & RQF_FLUSH_SEQ)) {
2265 unsigned long duration = jiffies - req->start_time;
2266 const int rw = rq_data_dir(req);
2267 struct hd_struct *part;
2270 cpu = part_stat_lock();
2273 part_stat_inc(cpu, part, ios[rw]);
2274 part_stat_add(cpu, part, ticks[rw], duration);
2275 part_round_stats(cpu, part);
2276 part_dec_in_flight(part, rw);
2278 hd_struct_put(part);
2285 * Don't process normal requests when queue is suspended
2286 * or in the process of suspending/resuming
2288 static struct request *blk_pm_peek_request(struct request_queue *q,
2291 if (q->dev && (q->rpm_status == RPM_SUSPENDED ||
2292 (q->rpm_status != RPM_ACTIVE && !(rq->rq_flags & RQF_PM))))
2298 static inline struct request *blk_pm_peek_request(struct request_queue *q,
2305 void blk_account_io_start(struct request *rq, bool new_io)
2307 struct hd_struct *part;
2308 int rw = rq_data_dir(rq);
2311 if (!blk_do_io_stat(rq))
2314 cpu = part_stat_lock();
2318 part_stat_inc(cpu, part, merges[rw]);
2320 part = disk_map_sector_rcu(rq->rq_disk, blk_rq_pos(rq));
2321 if (!hd_struct_try_get(part)) {
2323 * The partition is already being removed,
2324 * the request will be accounted on the disk only
2326 * We take a reference on disk->part0 although that
2327 * partition will never be deleted, so we can treat
2328 * it as any other partition.
2330 part = &rq->rq_disk->part0;
2331 hd_struct_get(part);
2333 part_round_stats(cpu, part);
2334 part_inc_in_flight(part, rw);
2342 * blk_peek_request - peek at the top of a request queue
2343 * @q: request queue to peek at
2346 * Return the request at the top of @q. The returned request
2347 * should be started using blk_start_request() before LLD starts
2351 * Pointer to the request at the top of @q if available. Null
2355 * queue_lock must be held.
2357 struct request *blk_peek_request(struct request_queue *q)
2362 while ((rq = __elv_next_request(q)) != NULL) {
2364 rq = blk_pm_peek_request(q, rq);
2368 if (!(rq->rq_flags & RQF_STARTED)) {
2370 * This is the first time the device driver
2371 * sees this request (possibly after
2372 * requeueing). Notify IO scheduler.
2374 if (rq->rq_flags & RQF_SORTED)
2375 elv_activate_rq(q, rq);
2378 * just mark as started even if we don't start
2379 * it, a request that has been delayed should
2380 * not be passed by new incoming requests
2382 rq->rq_flags |= RQF_STARTED;
2383 trace_block_rq_issue(q, rq);
2386 if (!q->boundary_rq || q->boundary_rq == rq) {
2387 q->end_sector = rq_end_sector(rq);
2388 q->boundary_rq = NULL;
2391 if (rq->rq_flags & RQF_DONTPREP)
2394 if (q->dma_drain_size && blk_rq_bytes(rq)) {
2396 * make sure space for the drain appears we
2397 * know we can do this because max_hw_segments
2398 * has been adjusted to be one fewer than the
2401 rq->nr_phys_segments++;
2407 ret = q->prep_rq_fn(q, rq);
2408 if (ret == BLKPREP_OK) {
2410 } else if (ret == BLKPREP_DEFER) {
2412 * the request may have been (partially) prepped.
2413 * we need to keep this request in the front to
2414 * avoid resource deadlock. RQF_STARTED will
2415 * prevent other fs requests from passing this one.
2417 if (q->dma_drain_size && blk_rq_bytes(rq) &&
2418 !(rq->rq_flags & RQF_DONTPREP)) {
2420 * remove the space for the drain we added
2421 * so that we don't add it again
2423 --rq->nr_phys_segments;
2428 } else if (ret == BLKPREP_KILL || ret == BLKPREP_INVALID) {
2429 int err = (ret == BLKPREP_INVALID) ? -EREMOTEIO : -EIO;
2431 rq->rq_flags |= RQF_QUIET;
2433 * Mark this request as started so we don't trigger
2434 * any debug logic in the end I/O path.
2436 blk_start_request(rq);
2437 __blk_end_request_all(rq, err);
2439 printk(KERN_ERR "%s: bad return=%d\n", __func__, ret);
2446 EXPORT_SYMBOL(blk_peek_request);
2448 void blk_dequeue_request(struct request *rq)
2450 struct request_queue *q = rq->q;
2452 BUG_ON(list_empty(&rq->queuelist));
2453 BUG_ON(ELV_ON_HASH(rq));
2455 list_del_init(&rq->queuelist);
2458 * the time frame between a request being removed from the lists
2459 * and to it is freed is accounted as io that is in progress at
2462 if (blk_account_rq(rq)) {
2463 q->in_flight[rq_is_sync(rq)]++;
2464 set_io_start_time_ns(rq);
2469 * blk_start_request - start request processing on the driver
2470 * @req: request to dequeue
2473 * Dequeue @req and start timeout timer on it. This hands off the
2474 * request to the driver.
2476 * Block internal functions which don't want to start timer should
2477 * call blk_dequeue_request().
2480 * queue_lock must be held.
2482 void blk_start_request(struct request *req)
2484 blk_dequeue_request(req);
2486 if (test_bit(QUEUE_FLAG_STATS, &req->q->queue_flags)) {
2487 blk_stat_set_issue_time(&req->issue_stat);
2488 req->rq_flags |= RQF_STATS;
2489 wbt_issue(req->q->rq_wb, &req->issue_stat);
2493 * We are now handing the request to the hardware, initialize
2494 * resid_len to full count and add the timeout handler.
2496 req->resid_len = blk_rq_bytes(req);
2497 if (unlikely(blk_bidi_rq(req)))
2498 req->next_rq->resid_len = blk_rq_bytes(req->next_rq);
2500 BUG_ON(test_bit(REQ_ATOM_COMPLETE, &req->atomic_flags));
2503 EXPORT_SYMBOL(blk_start_request);
2506 * blk_fetch_request - fetch a request from a request queue
2507 * @q: request queue to fetch a request from
2510 * Return the request at the top of @q. The request is started on
2511 * return and LLD can start processing it immediately.
2514 * Pointer to the request at the top of @q if available. Null
2518 * queue_lock must be held.
2520 struct request *blk_fetch_request(struct request_queue *q)
2524 rq = blk_peek_request(q);
2526 blk_start_request(rq);
2529 EXPORT_SYMBOL(blk_fetch_request);
2532 * blk_update_request - Special helper function for request stacking drivers
2533 * @req: the request being processed
2534 * @error: %0 for success, < %0 for error
2535 * @nr_bytes: number of bytes to complete @req
2538 * Ends I/O on a number of bytes attached to @req, but doesn't complete
2539 * the request structure even if @req doesn't have leftover.
2540 * If @req has leftover, sets it up for the next range of segments.
2542 * This special helper function is only for request stacking drivers
2543 * (e.g. request-based dm) so that they can handle partial completion.
2544 * Actual device drivers should use blk_end_request instead.
2546 * Passing the result of blk_rq_bytes() as @nr_bytes guarantees
2547 * %false return from this function.
2550 * %false - this request doesn't have any more data
2551 * %true - this request has more data
2553 bool blk_update_request(struct request *req, int error, unsigned int nr_bytes)
2557 trace_block_rq_complete(req->q, req, nr_bytes);
2563 * For fs requests, rq is just carrier of independent bio's
2564 * and each partial completion should be handled separately.
2565 * Reset per-request error on each partial completion.
2567 * TODO: tj: This is too subtle. It would be better to let
2568 * low level drivers do what they see fit.
2570 if (req->cmd_type == REQ_TYPE_FS)
2573 if (error && req->cmd_type == REQ_TYPE_FS &&
2574 !(req->rq_flags & RQF_QUIET)) {
2579 error_type = "recoverable transport";
2582 error_type = "critical target";
2585 error_type = "critical nexus";
2588 error_type = "timeout";
2591 error_type = "critical space allocation";
2594 error_type = "critical medium";
2601 printk_ratelimited(KERN_ERR "%s: %s error, dev %s, sector %llu\n",
2602 __func__, error_type, req->rq_disk ?
2603 req->rq_disk->disk_name : "?",
2604 (unsigned long long)blk_rq_pos(req));
2608 blk_account_io_completion(req, nr_bytes);
2612 struct bio *bio = req->bio;
2613 unsigned bio_bytes = min(bio->bi_iter.bi_size, nr_bytes);
2615 if (bio_bytes == bio->bi_iter.bi_size)
2616 req->bio = bio->bi_next;
2618 req_bio_endio(req, bio, bio_bytes, error);
2620 total_bytes += bio_bytes;
2621 nr_bytes -= bio_bytes;
2632 * Reset counters so that the request stacking driver
2633 * can find how many bytes remain in the request
2636 req->__data_len = 0;
2640 req->__data_len -= total_bytes;
2642 /* update sector only for requests with clear definition of sector */
2643 if (req->cmd_type == REQ_TYPE_FS)
2644 req->__sector += total_bytes >> 9;
2646 /* mixed attributes always follow the first bio */
2647 if (req->rq_flags & RQF_MIXED_MERGE) {
2648 req->cmd_flags &= ~REQ_FAILFAST_MASK;
2649 req->cmd_flags |= req->bio->bi_opf & REQ_FAILFAST_MASK;
2653 * If total number of sectors is less than the first segment
2654 * size, something has gone terribly wrong.
2656 if (blk_rq_bytes(req) < blk_rq_cur_bytes(req)) {
2657 blk_dump_rq_flags(req, "request botched");
2658 req->__data_len = blk_rq_cur_bytes(req);
2661 /* recalculate the number of segments */
2662 blk_recalc_rq_segments(req);
2666 EXPORT_SYMBOL_GPL(blk_update_request);
2668 static bool blk_update_bidi_request(struct request *rq, int error,
2669 unsigned int nr_bytes,
2670 unsigned int bidi_bytes)
2672 if (blk_update_request(rq, error, nr_bytes))
2675 /* Bidi request must be completed as a whole */
2676 if (unlikely(blk_bidi_rq(rq)) &&
2677 blk_update_request(rq->next_rq, error, bidi_bytes))
2680 if (blk_queue_add_random(rq->q))
2681 add_disk_randomness(rq->rq_disk);
2687 * blk_unprep_request - unprepare a request
2690 * This function makes a request ready for complete resubmission (or
2691 * completion). It happens only after all error handling is complete,
2692 * so represents the appropriate moment to deallocate any resources
2693 * that were allocated to the request in the prep_rq_fn. The queue
2694 * lock is held when calling this.
2696 void blk_unprep_request(struct request *req)
2698 struct request_queue *q = req->q;
2700 req->rq_flags &= ~RQF_DONTPREP;
2701 if (q->unprep_rq_fn)
2702 q->unprep_rq_fn(q, req);
2704 EXPORT_SYMBOL_GPL(blk_unprep_request);
2707 * queue lock must be held
2709 void blk_finish_request(struct request *req, int error)
2711 struct request_queue *q = req->q;
2713 if (req->rq_flags & RQF_STATS)
2714 blk_stat_add(&q->rq_stats[rq_data_dir(req)], req);
2716 if (req->rq_flags & RQF_QUEUED)
2717 blk_queue_end_tag(q, req);
2719 BUG_ON(blk_queued_rq(req));
2721 if (unlikely(laptop_mode) && req->cmd_type == REQ_TYPE_FS)
2722 laptop_io_completion(&req->q->backing_dev_info);
2724 blk_delete_timer(req);
2726 if (req->rq_flags & RQF_DONTPREP)
2727 blk_unprep_request(req);
2729 blk_account_io_done(req);
2732 wbt_done(req->q->rq_wb, &req->issue_stat);
2733 req->end_io(req, error);
2735 if (blk_bidi_rq(req))
2736 __blk_put_request(req->next_rq->q, req->next_rq);
2738 __blk_put_request(q, req);
2741 EXPORT_SYMBOL(blk_finish_request);
2744 * blk_end_bidi_request - Complete a bidi request
2745 * @rq: the request to complete
2746 * @error: %0 for success, < %0 for error
2747 * @nr_bytes: number of bytes to complete @rq
2748 * @bidi_bytes: number of bytes to complete @rq->next_rq
2751 * Ends I/O on a number of bytes attached to @rq and @rq->next_rq.
2752 * Drivers that supports bidi can safely call this member for any
2753 * type of request, bidi or uni. In the later case @bidi_bytes is
2757 * %false - we are done with this request
2758 * %true - still buffers pending for this request
2760 static bool blk_end_bidi_request(struct request *rq, int error,
2761 unsigned int nr_bytes, unsigned int bidi_bytes)
2763 struct request_queue *q = rq->q;
2764 unsigned long flags;
2766 if (blk_update_bidi_request(rq, error, nr_bytes, bidi_bytes))
2769 spin_lock_irqsave(q->queue_lock, flags);
2770 blk_finish_request(rq, error);
2771 spin_unlock_irqrestore(q->queue_lock, flags);
2777 * __blk_end_bidi_request - Complete a bidi request with queue lock held
2778 * @rq: the request to complete
2779 * @error: %0 for success, < %0 for error
2780 * @nr_bytes: number of bytes to complete @rq
2781 * @bidi_bytes: number of bytes to complete @rq->next_rq
2784 * Identical to blk_end_bidi_request() except that queue lock is
2785 * assumed to be locked on entry and remains so on return.
2788 * %false - we are done with this request
2789 * %true - still buffers pending for this request
2791 bool __blk_end_bidi_request(struct request *rq, int error,
2792 unsigned int nr_bytes, unsigned int bidi_bytes)
2794 if (blk_update_bidi_request(rq, error, nr_bytes, bidi_bytes))
2797 blk_finish_request(rq, error);
2803 * blk_end_request - Helper function for drivers to complete the request.
2804 * @rq: the request being processed
2805 * @error: %0 for success, < %0 for error
2806 * @nr_bytes: number of bytes to complete
2809 * Ends I/O on a number of bytes attached to @rq.
2810 * If @rq has leftover, sets it up for the next range of segments.
2813 * %false - we are done with this request
2814 * %true - still buffers pending for this request
2816 bool blk_end_request(struct request *rq, int error, unsigned int nr_bytes)
2818 return blk_end_bidi_request(rq, error, nr_bytes, 0);
2820 EXPORT_SYMBOL(blk_end_request);
2823 * blk_end_request_all - Helper function for drives to finish the request.
2824 * @rq: the request to finish
2825 * @error: %0 for success, < %0 for error
2828 * Completely finish @rq.
2830 void blk_end_request_all(struct request *rq, int error)
2833 unsigned int bidi_bytes = 0;
2835 if (unlikely(blk_bidi_rq(rq)))
2836 bidi_bytes = blk_rq_bytes(rq->next_rq);
2838 pending = blk_end_bidi_request(rq, error, blk_rq_bytes(rq), bidi_bytes);
2841 EXPORT_SYMBOL(blk_end_request_all);
2844 * blk_end_request_cur - Helper function to finish the current request chunk.
2845 * @rq: the request to finish the current chunk for
2846 * @error: %0 for success, < %0 for error
2849 * Complete the current consecutively mapped chunk from @rq.
2852 * %false - we are done with this request
2853 * %true - still buffers pending for this request
2855 bool blk_end_request_cur(struct request *rq, int error)
2857 return blk_end_request(rq, error, blk_rq_cur_bytes(rq));
2859 EXPORT_SYMBOL(blk_end_request_cur);
2862 * blk_end_request_err - Finish a request till the next failure boundary.
2863 * @rq: the request to finish till the next failure boundary for
2864 * @error: must be negative errno
2867 * Complete @rq till the next failure boundary.
2870 * %false - we are done with this request
2871 * %true - still buffers pending for this request
2873 bool blk_end_request_err(struct request *rq, int error)
2875 WARN_ON(error >= 0);
2876 return blk_end_request(rq, error, blk_rq_err_bytes(rq));
2878 EXPORT_SYMBOL_GPL(blk_end_request_err);
2881 * __blk_end_request - Helper function for drivers to complete the request.
2882 * @rq: the request being processed
2883 * @error: %0 for success, < %0 for error
2884 * @nr_bytes: number of bytes to complete
2887 * Must be called with queue lock held unlike blk_end_request().
2890 * %false - we are done with this request
2891 * %true - still buffers pending for this request
2893 bool __blk_end_request(struct request *rq, int error, unsigned int nr_bytes)
2895 return __blk_end_bidi_request(rq, error, nr_bytes, 0);
2897 EXPORT_SYMBOL(__blk_end_request);
2900 * __blk_end_request_all - Helper function for drives to finish the request.
2901 * @rq: the request to finish
2902 * @error: %0 for success, < %0 for error
2905 * Completely finish @rq. Must be called with queue lock held.
2907 void __blk_end_request_all(struct request *rq, int error)
2910 unsigned int bidi_bytes = 0;
2912 if (unlikely(blk_bidi_rq(rq)))
2913 bidi_bytes = blk_rq_bytes(rq->next_rq);
2915 pending = __blk_end_bidi_request(rq, error, blk_rq_bytes(rq), bidi_bytes);
2918 EXPORT_SYMBOL(__blk_end_request_all);
2921 * __blk_end_request_cur - Helper function to finish the current request chunk.
2922 * @rq: the request to finish the current chunk for
2923 * @error: %0 for success, < %0 for error
2926 * Complete the current consecutively mapped chunk from @rq. Must
2927 * be called with queue lock held.
2930 * %false - we are done with this request
2931 * %true - still buffers pending for this request
2933 bool __blk_end_request_cur(struct request *rq, int error)
2935 return __blk_end_request(rq, error, blk_rq_cur_bytes(rq));
2937 EXPORT_SYMBOL(__blk_end_request_cur);
2940 * __blk_end_request_err - Finish a request till the next failure boundary.
2941 * @rq: the request to finish till the next failure boundary for
2942 * @error: must be negative errno
2945 * Complete @rq till the next failure boundary. Must be called
2946 * with queue lock held.
2949 * %false - we are done with this request
2950 * %true - still buffers pending for this request
2952 bool __blk_end_request_err(struct request *rq, int error)
2954 WARN_ON(error >= 0);
2955 return __blk_end_request(rq, error, blk_rq_err_bytes(rq));
2957 EXPORT_SYMBOL_GPL(__blk_end_request_err);
2959 void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
2962 if (bio_has_data(bio))
2963 rq->nr_phys_segments = bio_phys_segments(q, bio);
2965 rq->__data_len = bio->bi_iter.bi_size;
2966 rq->bio = rq->biotail = bio;
2969 rq->rq_disk = bio->bi_bdev->bd_disk;
2972 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
2974 * rq_flush_dcache_pages - Helper function to flush all pages in a request
2975 * @rq: the request to be flushed
2978 * Flush all pages in @rq.
2980 void rq_flush_dcache_pages(struct request *rq)
2982 struct req_iterator iter;
2983 struct bio_vec bvec;
2985 rq_for_each_segment(bvec, rq, iter)
2986 flush_dcache_page(bvec.bv_page);
2988 EXPORT_SYMBOL_GPL(rq_flush_dcache_pages);
2992 * blk_lld_busy - Check if underlying low-level drivers of a device are busy
2993 * @q : the queue of the device being checked
2996 * Check if underlying low-level drivers of a device are busy.
2997 * If the drivers want to export their busy state, they must set own
2998 * exporting function using blk_queue_lld_busy() first.
3000 * Basically, this function is used only by request stacking drivers
3001 * to stop dispatching requests to underlying devices when underlying
3002 * devices are busy. This behavior helps more I/O merging on the queue
3003 * of the request stacking driver and prevents I/O throughput regression
3004 * on burst I/O load.
3007 * 0 - Not busy (The request stacking driver should dispatch request)
3008 * 1 - Busy (The request stacking driver should stop dispatching request)
3010 int blk_lld_busy(struct request_queue *q)
3013 return q->lld_busy_fn(q);
3017 EXPORT_SYMBOL_GPL(blk_lld_busy);
3020 * blk_rq_unprep_clone - Helper function to free all bios in a cloned request
3021 * @rq: the clone request to be cleaned up
3024 * Free all bios in @rq for a cloned request.
3026 void blk_rq_unprep_clone(struct request *rq)
3030 while ((bio = rq->bio) != NULL) {
3031 rq->bio = bio->bi_next;
3036 EXPORT_SYMBOL_GPL(blk_rq_unprep_clone);
3039 * Copy attributes of the original request to the clone request.
3040 * The actual data parts (e.g. ->cmd, ->sense) are not copied.
3042 static void __blk_rq_prep_clone(struct request *dst, struct request *src)
3044 dst->cpu = src->cpu;
3045 dst->cmd_flags = src->cmd_flags | REQ_NOMERGE;
3046 dst->cmd_type = src->cmd_type;
3047 dst->__sector = blk_rq_pos(src);
3048 dst->__data_len = blk_rq_bytes(src);
3049 dst->nr_phys_segments = src->nr_phys_segments;
3050 dst->ioprio = src->ioprio;
3051 dst->extra_len = src->extra_len;
3055 * blk_rq_prep_clone - Helper function to setup clone request
3056 * @rq: the request to be setup
3057 * @rq_src: original request to be cloned
3058 * @bs: bio_set that bios for clone are allocated from
3059 * @gfp_mask: memory allocation mask for bio
3060 * @bio_ctr: setup function to be called for each clone bio.
3061 * Returns %0 for success, non %0 for failure.
3062 * @data: private data to be passed to @bio_ctr
3065 * Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq.
3066 * The actual data parts of @rq_src (e.g. ->cmd, ->sense)
3067 * are not copied, and copying such parts is the caller's responsibility.
3068 * Also, pages which the original bios are pointing to are not copied
3069 * and the cloned bios just point same pages.
3070 * So cloned bios must be completed before original bios, which means
3071 * the caller must complete @rq before @rq_src.
3073 int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
3074 struct bio_set *bs, gfp_t gfp_mask,
3075 int (*bio_ctr)(struct bio *, struct bio *, void *),
3078 struct bio *bio, *bio_src;
3083 __rq_for_each_bio(bio_src, rq_src) {
3084 bio = bio_clone_fast(bio_src, gfp_mask, bs);
3088 if (bio_ctr && bio_ctr(bio, bio_src, data))
3092 rq->biotail->bi_next = bio;
3095 rq->bio = rq->biotail = bio;
3098 __blk_rq_prep_clone(rq, rq_src);
3105 blk_rq_unprep_clone(rq);
3109 EXPORT_SYMBOL_GPL(blk_rq_prep_clone);
3111 int kblockd_schedule_work(struct work_struct *work)
3113 return queue_work(kblockd_workqueue, work);
3115 EXPORT_SYMBOL(kblockd_schedule_work);
3117 int kblockd_schedule_work_on(int cpu, struct work_struct *work)
3119 return queue_work_on(cpu, kblockd_workqueue, work);
3121 EXPORT_SYMBOL(kblockd_schedule_work_on);
3123 int kblockd_schedule_delayed_work(struct delayed_work *dwork,
3124 unsigned long delay)
3126 return queue_delayed_work(kblockd_workqueue, dwork, delay);
3128 EXPORT_SYMBOL(kblockd_schedule_delayed_work);
3130 int kblockd_schedule_delayed_work_on(int cpu, struct delayed_work *dwork,
3131 unsigned long delay)
3133 return queue_delayed_work_on(cpu, kblockd_workqueue, dwork, delay);
3135 EXPORT_SYMBOL(kblockd_schedule_delayed_work_on);
3138 * blk_start_plug - initialize blk_plug and track it inside the task_struct
3139 * @plug: The &struct blk_plug that needs to be initialized
3142 * Tracking blk_plug inside the task_struct will help with auto-flushing the
3143 * pending I/O should the task end up blocking between blk_start_plug() and
3144 * blk_finish_plug(). This is important from a performance perspective, but
3145 * also ensures that we don't deadlock. For instance, if the task is blocking
3146 * for a memory allocation, memory reclaim could end up wanting to free a
3147 * page belonging to that request that is currently residing in our private
3148 * plug. By flushing the pending I/O when the process goes to sleep, we avoid
3149 * this kind of deadlock.
3151 void blk_start_plug(struct blk_plug *plug)
3153 struct task_struct *tsk = current;
3156 * If this is a nested plug, don't actually assign it.
3161 INIT_LIST_HEAD(&plug->list);
3162 INIT_LIST_HEAD(&plug->mq_list);
3163 INIT_LIST_HEAD(&plug->cb_list);
3165 * Store ordering should not be needed here, since a potential
3166 * preempt will imply a full memory barrier
3170 EXPORT_SYMBOL(blk_start_plug);
3172 static int plug_rq_cmp(void *priv, struct list_head *a, struct list_head *b)
3174 struct request *rqa = container_of(a, struct request, queuelist);
3175 struct request *rqb = container_of(b, struct request, queuelist);
3177 return !(rqa->q < rqb->q ||
3178 (rqa->q == rqb->q && blk_rq_pos(rqa) < blk_rq_pos(rqb)));
3182 * If 'from_schedule' is true, then postpone the dispatch of requests
3183 * until a safe kblockd context. We due this to avoid accidental big
3184 * additional stack usage in driver dispatch, in places where the originally
3185 * plugger did not intend it.
3187 static void queue_unplugged(struct request_queue *q, unsigned int depth,
3189 __releases(q->queue_lock)
3191 trace_block_unplug(q, depth, !from_schedule);
3194 blk_run_queue_async(q);
3197 spin_unlock(q->queue_lock);
3200 static void flush_plug_callbacks(struct blk_plug *plug, bool from_schedule)
3202 LIST_HEAD(callbacks);
3204 while (!list_empty(&plug->cb_list)) {
3205 list_splice_init(&plug->cb_list, &callbacks);
3207 while (!list_empty(&callbacks)) {
3208 struct blk_plug_cb *cb = list_first_entry(&callbacks,
3211 list_del(&cb->list);
3212 cb->callback(cb, from_schedule);
3217 struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug, void *data,
3220 struct blk_plug *plug = current->plug;
3221 struct blk_plug_cb *cb;
3226 list_for_each_entry(cb, &plug->cb_list, list)
3227 if (cb->callback == unplug && cb->data == data)
3230 /* Not currently on the callback list */
3231 BUG_ON(size < sizeof(*cb));
3232 cb = kzalloc(size, GFP_ATOMIC);
3235 cb->callback = unplug;
3236 list_add(&cb->list, &plug->cb_list);
3240 EXPORT_SYMBOL(blk_check_plugged);
3242 void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule)
3244 struct request_queue *q;
3245 unsigned long flags;
3250 flush_plug_callbacks(plug, from_schedule);
3252 if (!list_empty(&plug->mq_list))
3253 blk_mq_flush_plug_list(plug, from_schedule);
3255 if (list_empty(&plug->list))
3258 list_splice_init(&plug->list, &list);
3260 list_sort(NULL, &list, plug_rq_cmp);
3266 * Save and disable interrupts here, to avoid doing it for every
3267 * queue lock we have to take.
3269 local_irq_save(flags);
3270 while (!list_empty(&list)) {
3271 rq = list_entry_rq(list.next);
3272 list_del_init(&rq->queuelist);
3276 * This drops the queue lock
3279 queue_unplugged(q, depth, from_schedule);
3282 spin_lock(q->queue_lock);
3286 * Short-circuit if @q is dead
3288 if (unlikely(blk_queue_dying(q))) {
3289 __blk_end_request_all(rq, -ENODEV);
3294 * rq is already accounted, so use raw insert
3296 if (rq->cmd_flags & (REQ_PREFLUSH | REQ_FUA))
3297 __elv_add_request(q, rq, ELEVATOR_INSERT_FLUSH);
3299 __elv_add_request(q, rq, ELEVATOR_INSERT_SORT_MERGE);
3305 * This drops the queue lock
3308 queue_unplugged(q, depth, from_schedule);
3310 local_irq_restore(flags);
3313 void blk_finish_plug(struct blk_plug *plug)
3315 if (plug != current->plug)
3317 blk_flush_plug_list(plug, false);
3319 current->plug = NULL;
3321 EXPORT_SYMBOL(blk_finish_plug);
3325 * blk_pm_runtime_init - Block layer runtime PM initialization routine
3326 * @q: the queue of the device
3327 * @dev: the device the queue belongs to
3330 * Initialize runtime-PM-related fields for @q and start auto suspend for
3331 * @dev. Drivers that want to take advantage of request-based runtime PM
3332 * should call this function after @dev has been initialized, and its
3333 * request queue @q has been allocated, and runtime PM for it can not happen
3334 * yet(either due to disabled/forbidden or its usage_count > 0). In most
3335 * cases, driver should call this function before any I/O has taken place.
3337 * This function takes care of setting up using auto suspend for the device,
3338 * the autosuspend delay is set to -1 to make runtime suspend impossible
3339 * until an updated value is either set by user or by driver. Drivers do
3340 * not need to touch other autosuspend settings.
3342 * The block layer runtime PM is request based, so only works for drivers
3343 * that use request as their IO unit instead of those directly use bio's.
3345 void blk_pm_runtime_init(struct request_queue *q, struct device *dev)
3348 q->rpm_status = RPM_ACTIVE;
3349 pm_runtime_set_autosuspend_delay(q->dev, -1);
3350 pm_runtime_use_autosuspend(q->dev);
3352 EXPORT_SYMBOL(blk_pm_runtime_init);
3355 * blk_pre_runtime_suspend - Pre runtime suspend check
3356 * @q: the queue of the device
3359 * This function will check if runtime suspend is allowed for the device
3360 * by examining if there are any requests pending in the queue. If there
3361 * are requests pending, the device can not be runtime suspended; otherwise,
3362 * the queue's status will be updated to SUSPENDING and the driver can
3363 * proceed to suspend the device.
3365 * For the not allowed case, we mark last busy for the device so that
3366 * runtime PM core will try to autosuspend it some time later.
3368 * This function should be called near the start of the device's
3369 * runtime_suspend callback.
3372 * 0 - OK to runtime suspend the device
3373 * -EBUSY - Device should not be runtime suspended
3375 int blk_pre_runtime_suspend(struct request_queue *q)
3382 spin_lock_irq(q->queue_lock);
3383 if (q->nr_pending) {
3385 pm_runtime_mark_last_busy(q->dev);
3387 q->rpm_status = RPM_SUSPENDING;
3389 spin_unlock_irq(q->queue_lock);
3392 EXPORT_SYMBOL(blk_pre_runtime_suspend);
3395 * blk_post_runtime_suspend - Post runtime suspend processing
3396 * @q: the queue of the device
3397 * @err: return value of the device's runtime_suspend function
3400 * Update the queue's runtime status according to the return value of the
3401 * device's runtime suspend function and mark last busy for the device so
3402 * that PM core will try to auto suspend the device at a later time.
3404 * This function should be called near the end of the device's
3405 * runtime_suspend callback.
3407 void blk_post_runtime_suspend(struct request_queue *q, int err)
3412 spin_lock_irq(q->queue_lock);
3414 q->rpm_status = RPM_SUSPENDED;
3416 q->rpm_status = RPM_ACTIVE;
3417 pm_runtime_mark_last_busy(q->dev);
3419 spin_unlock_irq(q->queue_lock);
3421 EXPORT_SYMBOL(blk_post_runtime_suspend);
3424 * blk_pre_runtime_resume - Pre runtime resume processing
3425 * @q: the queue of the device
3428 * Update the queue's runtime status to RESUMING in preparation for the
3429 * runtime resume of the device.
3431 * This function should be called near the start of the device's
3432 * runtime_resume callback.
3434 void blk_pre_runtime_resume(struct request_queue *q)
3439 spin_lock_irq(q->queue_lock);
3440 q->rpm_status = RPM_RESUMING;
3441 spin_unlock_irq(q->queue_lock);
3443 EXPORT_SYMBOL(blk_pre_runtime_resume);
3446 * blk_post_runtime_resume - Post runtime resume processing
3447 * @q: the queue of the device
3448 * @err: return value of the device's runtime_resume function
3451 * Update the queue's runtime status according to the return value of the
3452 * device's runtime_resume function. If it is successfully resumed, process
3453 * the requests that are queued into the device's queue when it is resuming
3454 * and then mark last busy and initiate autosuspend for it.
3456 * This function should be called near the end of the device's
3457 * runtime_resume callback.
3459 void blk_post_runtime_resume(struct request_queue *q, int err)
3464 spin_lock_irq(q->queue_lock);
3466 q->rpm_status = RPM_ACTIVE;
3468 pm_runtime_mark_last_busy(q->dev);
3469 pm_request_autosuspend(q->dev);
3471 q->rpm_status = RPM_SUSPENDED;
3473 spin_unlock_irq(q->queue_lock);
3475 EXPORT_SYMBOL(blk_post_runtime_resume);
3478 * blk_set_runtime_active - Force runtime status of the queue to be active
3479 * @q: the queue of the device
3481 * If the device is left runtime suspended during system suspend the resume
3482 * hook typically resumes the device and corrects runtime status
3483 * accordingly. However, that does not affect the queue runtime PM status
3484 * which is still "suspended". This prevents processing requests from the
3487 * This function can be used in driver's resume hook to correct queue
3488 * runtime PM status and re-enable peeking requests from the queue. It
3489 * should be called before first request is added to the queue.
3491 void blk_set_runtime_active(struct request_queue *q)
3493 spin_lock_irq(q->queue_lock);
3494 q->rpm_status = RPM_ACTIVE;
3495 pm_runtime_mark_last_busy(q->dev);
3496 pm_request_autosuspend(q->dev);
3497 spin_unlock_irq(q->queue_lock);
3499 EXPORT_SYMBOL(blk_set_runtime_active);
3502 int __init blk_dev_init(void)
3504 BUILD_BUG_ON(REQ_OP_LAST >= (1 << REQ_OP_BITS));
3505 BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 *
3506 FIELD_SIZEOF(struct request, cmd_flags));
3507 BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 *
3508 FIELD_SIZEOF(struct bio, bi_opf));
3510 /* used for unplugging and affects IO latency/throughput - HIGHPRI */
3511 kblockd_workqueue = alloc_workqueue("kblockd",
3512 WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
3513 if (!kblockd_workqueue)
3514 panic("Failed to create kblockd\n");
3516 request_cachep = kmem_cache_create("blkdev_requests",
3517 sizeof(struct request), 0, SLAB_PANIC, NULL);
3519 blk_requestq_cachep = kmem_cache_create("request_queue",
3520 sizeof(struct request_queue), 0, SLAB_PANIC, NULL);