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>
36 #define CREATE_TRACE_POINTS
37 #include <trace/events/block.h>
40 #include "blk-cgroup.h"
43 EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap
);
44 EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap
);
45 EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete
);
46 EXPORT_TRACEPOINT_SYMBOL_GPL(block_split
);
47 EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug
);
49 DEFINE_IDA(blk_queue_ida
);
52 * For the allocated request tables
54 struct kmem_cache
*request_cachep
= NULL
;
57 * For queue allocation
59 struct kmem_cache
*blk_requestq_cachep
;
62 * Controlling structure to kblockd
64 static struct workqueue_struct
*kblockd_workqueue
;
66 void blk_queue_congestion_threshold(struct request_queue
*q
)
70 nr
= q
->nr_requests
- (q
->nr_requests
/ 8) + 1;
71 if (nr
> q
->nr_requests
)
73 q
->nr_congestion_on
= nr
;
75 nr
= q
->nr_requests
- (q
->nr_requests
/ 8) - (q
->nr_requests
/ 16) - 1;
78 q
->nr_congestion_off
= nr
;
82 * blk_get_backing_dev_info - get the address of a queue's backing_dev_info
85 * Locates the passed device's request queue and returns the address of its
86 * backing_dev_info. This function can only be called if @bdev is opened
87 * and the return value is never NULL.
89 struct backing_dev_info
*blk_get_backing_dev_info(struct block_device
*bdev
)
91 struct request_queue
*q
= bdev_get_queue(bdev
);
93 return &q
->backing_dev_info
;
95 EXPORT_SYMBOL(blk_get_backing_dev_info
);
97 void blk_rq_init(struct request_queue
*q
, struct request
*rq
)
99 memset(rq
, 0, sizeof(*rq
));
101 INIT_LIST_HEAD(&rq
->queuelist
);
102 INIT_LIST_HEAD(&rq
->timeout_list
);
105 rq
->__sector
= (sector_t
) -1;
106 INIT_HLIST_NODE(&rq
->hash
);
107 RB_CLEAR_NODE(&rq
->rb_node
);
109 rq
->cmd_len
= BLK_MAX_CDB
;
111 rq
->start_time
= jiffies
;
112 set_start_time_ns(rq
);
115 EXPORT_SYMBOL(blk_rq_init
);
117 static void req_bio_endio(struct request
*rq
, struct bio
*bio
,
118 unsigned int nbytes
, int error
)
121 clear_bit(BIO_UPTODATE
, &bio
->bi_flags
);
122 else if (!test_bit(BIO_UPTODATE
, &bio
->bi_flags
))
125 if (unlikely(rq
->cmd_flags
& REQ_QUIET
))
126 set_bit(BIO_QUIET
, &bio
->bi_flags
);
128 bio_advance(bio
, nbytes
);
130 /* don't actually finish bio if it's part of flush sequence */
131 if (bio
->bi_iter
.bi_size
== 0 && !(rq
->cmd_flags
& REQ_FLUSH_SEQ
))
132 bio_endio(bio
, error
);
135 void blk_dump_rq_flags(struct request
*rq
, char *msg
)
139 printk(KERN_INFO
"%s: dev %s: type=%x, flags=%llx\n", msg
,
140 rq
->rq_disk
? rq
->rq_disk
->disk_name
: "?", rq
->cmd_type
,
141 (unsigned long long) rq
->cmd_flags
);
143 printk(KERN_INFO
" sector %llu, nr/cnr %u/%u\n",
144 (unsigned long long)blk_rq_pos(rq
),
145 blk_rq_sectors(rq
), blk_rq_cur_sectors(rq
));
146 printk(KERN_INFO
" bio %p, biotail %p, len %u\n",
147 rq
->bio
, rq
->biotail
, blk_rq_bytes(rq
));
149 if (rq
->cmd_type
== REQ_TYPE_BLOCK_PC
) {
150 printk(KERN_INFO
" cdb: ");
151 for (bit
= 0; bit
< BLK_MAX_CDB
; bit
++)
152 printk("%02x ", rq
->cmd
[bit
]);
156 EXPORT_SYMBOL(blk_dump_rq_flags
);
158 static void blk_delay_work(struct work_struct
*work
)
160 struct request_queue
*q
;
162 q
= container_of(work
, struct request_queue
, delay_work
.work
);
163 spin_lock_irq(q
->queue_lock
);
165 spin_unlock_irq(q
->queue_lock
);
169 * blk_delay_queue - restart queueing after defined interval
170 * @q: The &struct request_queue in question
171 * @msecs: Delay in msecs
174 * Sometimes queueing needs to be postponed for a little while, to allow
175 * resources to come back. This function will make sure that queueing is
176 * restarted around the specified time. Queue lock must be held.
178 void blk_delay_queue(struct request_queue
*q
, unsigned long msecs
)
180 if (likely(!blk_queue_dead(q
)))
181 queue_delayed_work(kblockd_workqueue
, &q
->delay_work
,
182 msecs_to_jiffies(msecs
));
184 EXPORT_SYMBOL(blk_delay_queue
);
187 * blk_start_queue - restart a previously stopped queue
188 * @q: The &struct request_queue in question
191 * blk_start_queue() will clear the stop flag on the queue, and call
192 * the request_fn for the queue if it was in a stopped state when
193 * entered. Also see blk_stop_queue(). Queue lock must be held.
195 void blk_start_queue(struct request_queue
*q
)
197 WARN_ON(!irqs_disabled());
199 queue_flag_clear(QUEUE_FLAG_STOPPED
, q
);
202 EXPORT_SYMBOL(blk_start_queue
);
205 * blk_stop_queue - stop a queue
206 * @q: The &struct request_queue in question
209 * The Linux block layer assumes that a block driver will consume all
210 * entries on the request queue when the request_fn strategy is called.
211 * Often this will not happen, because of hardware limitations (queue
212 * depth settings). If a device driver gets a 'queue full' response,
213 * or if it simply chooses not to queue more I/O at one point, it can
214 * call this function to prevent the request_fn from being called until
215 * the driver has signalled it's ready to go again. This happens by calling
216 * blk_start_queue() to restart queue operations. Queue lock must be held.
218 void blk_stop_queue(struct request_queue
*q
)
220 cancel_delayed_work(&q
->delay_work
);
221 queue_flag_set(QUEUE_FLAG_STOPPED
, q
);
223 EXPORT_SYMBOL(blk_stop_queue
);
226 * blk_sync_queue - cancel any pending callbacks on a queue
230 * The block layer may perform asynchronous callback activity
231 * on a queue, such as calling the unplug function after a timeout.
232 * A block device may call blk_sync_queue to ensure that any
233 * such activity is cancelled, thus allowing it to release resources
234 * that the callbacks might use. The caller must already have made sure
235 * that its ->make_request_fn will not re-add plugging prior to calling
238 * This function does not cancel any asynchronous activity arising
239 * out of elevator or throttling code. That would require elevator_exit()
240 * and blkcg_exit_queue() to be called with queue lock initialized.
243 void blk_sync_queue(struct request_queue
*q
)
245 del_timer_sync(&q
->timeout
);
248 struct blk_mq_hw_ctx
*hctx
;
251 queue_for_each_hw_ctx(q
, hctx
, i
) {
252 cancel_delayed_work_sync(&hctx
->run_work
);
253 cancel_delayed_work_sync(&hctx
->delay_work
);
256 cancel_delayed_work_sync(&q
->delay_work
);
259 EXPORT_SYMBOL(blk_sync_queue
);
262 * __blk_run_queue_uncond - run a queue whether or not it has been stopped
263 * @q: The queue to run
266 * Invoke request handling on a queue if there are any pending requests.
267 * May be used to restart request handling after a request has completed.
268 * This variant runs the queue whether or not the queue has been
269 * stopped. Must be called with the queue lock held and interrupts
270 * disabled. See also @blk_run_queue.
272 inline void __blk_run_queue_uncond(struct request_queue
*q
)
274 if (unlikely(blk_queue_dead(q
)))
278 * Some request_fn implementations, e.g. scsi_request_fn(), unlock
279 * the queue lock internally. As a result multiple threads may be
280 * running such a request function concurrently. Keep track of the
281 * number of active request_fn invocations such that blk_drain_queue()
282 * can wait until all these request_fn calls have finished.
284 q
->request_fn_active
++;
286 q
->request_fn_active
--;
288 EXPORT_SYMBOL_GPL(__blk_run_queue_uncond
);
291 * __blk_run_queue - run a single device queue
292 * @q: The queue to run
295 * See @blk_run_queue. This variant must be called with the queue lock
296 * held and interrupts disabled.
298 void __blk_run_queue(struct request_queue
*q
)
300 if (unlikely(blk_queue_stopped(q
)))
303 __blk_run_queue_uncond(q
);
305 EXPORT_SYMBOL(__blk_run_queue
);
308 * blk_run_queue_async - run a single device queue in workqueue context
309 * @q: The queue to run
312 * Tells kblockd to perform the equivalent of @blk_run_queue on behalf
313 * of us. The caller must hold the queue lock.
315 void blk_run_queue_async(struct request_queue
*q
)
317 if (likely(!blk_queue_stopped(q
) && !blk_queue_dead(q
)))
318 mod_delayed_work(kblockd_workqueue
, &q
->delay_work
, 0);
320 EXPORT_SYMBOL(blk_run_queue_async
);
323 * blk_run_queue - run a single device queue
324 * @q: The queue to run
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.
330 void blk_run_queue(struct request_queue
*q
)
334 spin_lock_irqsave(q
->queue_lock
, flags
);
336 spin_unlock_irqrestore(q
->queue_lock
, flags
);
338 EXPORT_SYMBOL(blk_run_queue
);
340 void blk_put_queue(struct request_queue
*q
)
342 kobject_put(&q
->kobj
);
344 EXPORT_SYMBOL(blk_put_queue
);
347 * __blk_drain_queue - drain requests from request_queue
349 * @drain_all: whether to drain all requests or only the ones w/ ELVPRIV
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.
355 static void __blk_drain_queue(struct request_queue
*q
, bool drain_all
)
356 __releases(q
->queue_lock
)
357 __acquires(q
->queue_lock
)
361 lockdep_assert_held(q
->queue_lock
);
367 * The caller might be trying to drain @q before its
368 * elevator is initialized.
371 elv_drain_elevator(q
);
373 blkcg_drain_queue(q
);
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.
382 if (!list_empty(&q
->queue_head
) && q
->request_fn
)
385 drain
|= q
->nr_rqs_elvpriv
;
386 drain
|= q
->request_fn_active
;
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.
394 struct blk_flush_queue
*fq
= blk_get_flush_queue(q
, NULL
);
395 drain
|= !list_empty(&q
->queue_head
);
396 for (i
= 0; i
< 2; i
++) {
397 drain
|= q
->nr_rqs
[i
];
398 drain
|= q
->in_flight
[i
];
400 drain
|= !list_empty(&fq
->flush_queue
[i
]);
407 spin_unlock_irq(q
->queue_lock
);
411 spin_lock_irq(q
->queue_lock
);
415 * With queue marked dead, any woken up waiter will fail the
416 * allocation path, so the wakeup chaining is lost and we're
417 * left with hung waiters. We need to wake up those waiters.
420 struct request_list
*rl
;
422 blk_queue_for_each_rl(rl
, q
)
423 for (i
= 0; i
< ARRAY_SIZE(rl
->wait
); i
++)
424 wake_up_all(&rl
->wait
[i
]);
429 * blk_queue_bypass_start - enter queue bypass mode
430 * @q: queue of interest
432 * In bypass mode, only the dispatch FIFO queue of @q is used. This
433 * function makes @q enter bypass mode and drains all requests which were
434 * throttled or issued before. On return, it's guaranteed that no request
435 * is being throttled or has ELVPRIV set and blk_queue_bypass() %true
436 * inside queue or RCU read lock.
438 void blk_queue_bypass_start(struct request_queue
*q
)
440 spin_lock_irq(q
->queue_lock
);
442 queue_flag_set(QUEUE_FLAG_BYPASS
, q
);
443 spin_unlock_irq(q
->queue_lock
);
446 * Queues start drained. Skip actual draining till init is
447 * complete. This avoids lenghty delays during queue init which
448 * can happen many times during boot.
450 if (blk_queue_init_done(q
)) {
451 spin_lock_irq(q
->queue_lock
);
452 __blk_drain_queue(q
, false);
453 spin_unlock_irq(q
->queue_lock
);
455 /* ensure blk_queue_bypass() is %true inside RCU read lock */
459 EXPORT_SYMBOL_GPL(blk_queue_bypass_start
);
462 * blk_queue_bypass_end - leave queue bypass mode
463 * @q: queue of interest
465 * Leave bypass mode and restore the normal queueing behavior.
467 void blk_queue_bypass_end(struct request_queue
*q
)
469 spin_lock_irq(q
->queue_lock
);
470 if (!--q
->bypass_depth
)
471 queue_flag_clear(QUEUE_FLAG_BYPASS
, q
);
472 WARN_ON_ONCE(q
->bypass_depth
< 0);
473 spin_unlock_irq(q
->queue_lock
);
475 EXPORT_SYMBOL_GPL(blk_queue_bypass_end
);
477 void blk_set_queue_dying(struct request_queue
*q
)
479 queue_flag_set_unlocked(QUEUE_FLAG_DYING
, q
);
482 blk_mq_wake_waiters(q
);
484 struct request_list
*rl
;
486 blk_queue_for_each_rl(rl
, q
) {
488 wake_up(&rl
->wait
[BLK_RW_SYNC
]);
489 wake_up(&rl
->wait
[BLK_RW_ASYNC
]);
494 EXPORT_SYMBOL_GPL(blk_set_queue_dying
);
497 * blk_cleanup_queue - shutdown a request queue
498 * @q: request queue to shutdown
500 * Mark @q DYING, drain all pending requests, mark @q DEAD, destroy and
501 * put it. All future requests will be failed immediately with -ENODEV.
503 void blk_cleanup_queue(struct request_queue
*q
)
505 spinlock_t
*lock
= q
->queue_lock
;
507 /* mark @q DYING, no new request or merges will be allowed afterwards */
508 mutex_lock(&q
->sysfs_lock
);
509 blk_set_queue_dying(q
);
513 * A dying queue is permanently in bypass mode till released. Note
514 * that, unlike blk_queue_bypass_start(), we aren't performing
515 * synchronize_rcu() after entering bypass mode to avoid the delay
516 * as some drivers create and destroy a lot of queues while
517 * probing. This is still safe because blk_release_queue() will be
518 * called only after the queue refcnt drops to zero and nothing,
519 * RCU or not, would be traversing the queue by then.
522 queue_flag_set(QUEUE_FLAG_BYPASS
, q
);
524 queue_flag_set(QUEUE_FLAG_NOMERGES
, q
);
525 queue_flag_set(QUEUE_FLAG_NOXMERGES
, q
);
526 queue_flag_set(QUEUE_FLAG_DYING
, q
);
527 spin_unlock_irq(lock
);
528 mutex_unlock(&q
->sysfs_lock
);
531 * Drain all requests queued before DYING marking. Set DEAD flag to
532 * prevent that q->request_fn() gets invoked after draining finished.
535 blk_mq_freeze_queue(q
);
539 __blk_drain_queue(q
, true);
541 queue_flag_set(QUEUE_FLAG_DEAD
, q
);
542 spin_unlock_irq(lock
);
544 /* @q won't process any more request, flush async actions */
545 del_timer_sync(&q
->backing_dev_info
.laptop_mode_wb_timer
);
549 blk_mq_free_queue(q
);
552 if (q
->queue_lock
!= &q
->__queue_lock
)
553 q
->queue_lock
= &q
->__queue_lock
;
554 spin_unlock_irq(lock
);
556 /* @q is and will stay empty, shutdown and put */
559 EXPORT_SYMBOL(blk_cleanup_queue
);
561 /* Allocate memory local to the request queue */
562 static void *alloc_request_struct(gfp_t gfp_mask
, void *data
)
564 int nid
= (int)(long)data
;
565 return kmem_cache_alloc_node(request_cachep
, gfp_mask
, nid
);
568 static void free_request_struct(void *element
, void *unused
)
570 kmem_cache_free(request_cachep
, element
);
573 int blk_init_rl(struct request_list
*rl
, struct request_queue
*q
,
576 if (unlikely(rl
->rq_pool
))
580 rl
->count
[BLK_RW_SYNC
] = rl
->count
[BLK_RW_ASYNC
] = 0;
581 rl
->starved
[BLK_RW_SYNC
] = rl
->starved
[BLK_RW_ASYNC
] = 0;
582 init_waitqueue_head(&rl
->wait
[BLK_RW_SYNC
]);
583 init_waitqueue_head(&rl
->wait
[BLK_RW_ASYNC
]);
585 rl
->rq_pool
= mempool_create_node(BLKDEV_MIN_RQ
, alloc_request_struct
,
587 (void *)(long)q
->node
, gfp_mask
,
595 void blk_exit_rl(struct request_list
*rl
)
598 mempool_destroy(rl
->rq_pool
);
601 struct request_queue
*blk_alloc_queue(gfp_t gfp_mask
)
603 return blk_alloc_queue_node(gfp_mask
, NUMA_NO_NODE
);
605 EXPORT_SYMBOL(blk_alloc_queue
);
607 struct request_queue
*blk_alloc_queue_node(gfp_t gfp_mask
, int node_id
)
609 struct request_queue
*q
;
612 q
= kmem_cache_alloc_node(blk_requestq_cachep
,
613 gfp_mask
| __GFP_ZERO
, node_id
);
617 q
->id
= ida_simple_get(&blk_queue_ida
, 0, 0, gfp_mask
);
621 q
->backing_dev_info
.ra_pages
=
622 (VM_MAX_READAHEAD
* 1024) / PAGE_CACHE_SIZE
;
623 q
->backing_dev_info
.state
= 0;
624 q
->backing_dev_info
.capabilities
= 0;
625 q
->backing_dev_info
.name
= "block";
628 err
= bdi_init(&q
->backing_dev_info
);
632 setup_timer(&q
->backing_dev_info
.laptop_mode_wb_timer
,
633 laptop_mode_timer_fn
, (unsigned long) q
);
634 setup_timer(&q
->timeout
, blk_rq_timed_out_timer
, (unsigned long) q
);
635 INIT_LIST_HEAD(&q
->queue_head
);
636 INIT_LIST_HEAD(&q
->timeout_list
);
637 INIT_LIST_HEAD(&q
->icq_list
);
638 #ifdef CONFIG_BLK_CGROUP
639 INIT_LIST_HEAD(&q
->blkg_list
);
641 INIT_DELAYED_WORK(&q
->delay_work
, blk_delay_work
);
643 kobject_init(&q
->kobj
, &blk_queue_ktype
);
645 mutex_init(&q
->sysfs_lock
);
646 spin_lock_init(&q
->__queue_lock
);
649 * By default initialize queue_lock to internal lock and driver can
650 * override it later if need be.
652 q
->queue_lock
= &q
->__queue_lock
;
655 * A queue starts its life with bypass turned on to avoid
656 * unnecessary bypass on/off overhead and nasty surprises during
657 * init. The initial bypass will be finished when the queue is
658 * registered by blk_register_queue().
661 __set_bit(QUEUE_FLAG_BYPASS
, &q
->queue_flags
);
663 init_waitqueue_head(&q
->mq_freeze_wq
);
665 if (blkcg_init_queue(q
))
671 bdi_destroy(&q
->backing_dev_info
);
673 ida_simple_remove(&blk_queue_ida
, q
->id
);
675 kmem_cache_free(blk_requestq_cachep
, q
);
678 EXPORT_SYMBOL(blk_alloc_queue_node
);
681 * blk_init_queue - prepare a request queue for use with a block device
682 * @rfn: The function to be called to process requests that have been
683 * placed on the queue.
684 * @lock: Request queue spin lock
687 * If a block device wishes to use the standard request handling procedures,
688 * which sorts requests and coalesces adjacent requests, then it must
689 * call blk_init_queue(). The function @rfn will be called when there
690 * are requests on the queue that need to be processed. If the device
691 * supports plugging, then @rfn may not be called immediately when requests
692 * are available on the queue, but may be called at some time later instead.
693 * Plugged queues are generally unplugged when a buffer belonging to one
694 * of the requests on the queue is needed, or due to memory pressure.
696 * @rfn is not required, or even expected, to remove all requests off the
697 * queue, but only as many as it can handle at a time. If it does leave
698 * requests on the queue, it is responsible for arranging that the requests
699 * get dealt with eventually.
701 * The queue spin lock must be held while manipulating the requests on the
702 * request queue; this lock will be taken also from interrupt context, so irq
703 * disabling is needed for it.
705 * Function returns a pointer to the initialized request queue, or %NULL if
709 * blk_init_queue() must be paired with a blk_cleanup_queue() call
710 * when the block device is deactivated (such as at module unload).
713 struct request_queue
*blk_init_queue(request_fn_proc
*rfn
, spinlock_t
*lock
)
715 return blk_init_queue_node(rfn
, lock
, NUMA_NO_NODE
);
717 EXPORT_SYMBOL(blk_init_queue
);
719 struct request_queue
*
720 blk_init_queue_node(request_fn_proc
*rfn
, spinlock_t
*lock
, int node_id
)
722 struct request_queue
*uninit_q
, *q
;
724 uninit_q
= blk_alloc_queue_node(GFP_KERNEL
, node_id
);
728 q
= blk_init_allocated_queue(uninit_q
, rfn
, lock
);
730 blk_cleanup_queue(uninit_q
);
734 EXPORT_SYMBOL(blk_init_queue_node
);
736 struct request_queue
*
737 blk_init_allocated_queue(struct request_queue
*q
, request_fn_proc
*rfn
,
743 q
->fq
= blk_alloc_flush_queue(q
, NUMA_NO_NODE
, 0);
747 if (blk_init_rl(&q
->root_rl
, q
, GFP_KERNEL
))
751 q
->prep_rq_fn
= NULL
;
752 q
->unprep_rq_fn
= NULL
;
753 q
->queue_flags
|= QUEUE_FLAG_DEFAULT
;
755 /* Override internal queue lock with supplied lock pointer */
757 q
->queue_lock
= lock
;
760 * This also sets hw/phys segments, boundary and size
762 blk_queue_make_request(q
, blk_queue_bio
);
764 q
->sg_reserved_size
= INT_MAX
;
766 /* Protect q->elevator from elevator_change */
767 mutex_lock(&q
->sysfs_lock
);
770 if (elevator_init(q
, NULL
)) {
771 mutex_unlock(&q
->sysfs_lock
);
775 mutex_unlock(&q
->sysfs_lock
);
780 blk_free_flush_queue(q
->fq
);
783 EXPORT_SYMBOL(blk_init_allocated_queue
);
785 bool blk_get_queue(struct request_queue
*q
)
787 if (likely(!blk_queue_dying(q
))) {
794 EXPORT_SYMBOL(blk_get_queue
);
796 static inline void blk_free_request(struct request_list
*rl
, struct request
*rq
)
798 if (rq
->cmd_flags
& REQ_ELVPRIV
) {
799 elv_put_request(rl
->q
, rq
);
801 put_io_context(rq
->elv
.icq
->ioc
);
804 mempool_free(rq
, rl
->rq_pool
);
808 * ioc_batching returns true if the ioc is a valid batching request and
809 * should be given priority access to a request.
811 static inline int ioc_batching(struct request_queue
*q
, struct io_context
*ioc
)
817 * Make sure the process is able to allocate at least 1 request
818 * even if the batch times out, otherwise we could theoretically
821 return ioc
->nr_batch_requests
== q
->nr_batching
||
822 (ioc
->nr_batch_requests
> 0
823 && time_before(jiffies
, ioc
->last_waited
+ BLK_BATCH_TIME
));
827 * ioc_set_batching sets ioc to be a new "batcher" if it is not one. This
828 * will cause the process to be a "batcher" on all queues in the system. This
829 * is the behaviour we want though - once it gets a wakeup it should be given
832 static void ioc_set_batching(struct request_queue
*q
, struct io_context
*ioc
)
834 if (!ioc
|| ioc_batching(q
, ioc
))
837 ioc
->nr_batch_requests
= q
->nr_batching
;
838 ioc
->last_waited
= jiffies
;
841 static void __freed_request(struct request_list
*rl
, int sync
)
843 struct request_queue
*q
= rl
->q
;
846 * bdi isn't aware of blkcg yet. As all async IOs end up root
847 * blkcg anyway, just use root blkcg state.
849 if (rl
== &q
->root_rl
&&
850 rl
->count
[sync
] < queue_congestion_off_threshold(q
))
851 blk_clear_queue_congested(q
, sync
);
853 if (rl
->count
[sync
] + 1 <= q
->nr_requests
) {
854 if (waitqueue_active(&rl
->wait
[sync
]))
855 wake_up(&rl
->wait
[sync
]);
857 blk_clear_rl_full(rl
, sync
);
862 * A request has just been released. Account for it, update the full and
863 * congestion status, wake up any waiters. Called under q->queue_lock.
865 static void freed_request(struct request_list
*rl
, unsigned int flags
)
867 struct request_queue
*q
= rl
->q
;
868 int sync
= rw_is_sync(flags
);
872 if (flags
& REQ_ELVPRIV
)
875 __freed_request(rl
, sync
);
877 if (unlikely(rl
->starved
[sync
^ 1]))
878 __freed_request(rl
, sync
^ 1);
881 int blk_update_nr_requests(struct request_queue
*q
, unsigned int nr
)
883 struct request_list
*rl
;
885 spin_lock_irq(q
->queue_lock
);
887 blk_queue_congestion_threshold(q
);
889 /* congestion isn't cgroup aware and follows root blkcg for now */
892 if (rl
->count
[BLK_RW_SYNC
] >= queue_congestion_on_threshold(q
))
893 blk_set_queue_congested(q
, BLK_RW_SYNC
);
894 else if (rl
->count
[BLK_RW_SYNC
] < queue_congestion_off_threshold(q
))
895 blk_clear_queue_congested(q
, BLK_RW_SYNC
);
897 if (rl
->count
[BLK_RW_ASYNC
] >= queue_congestion_on_threshold(q
))
898 blk_set_queue_congested(q
, BLK_RW_ASYNC
);
899 else if (rl
->count
[BLK_RW_ASYNC
] < queue_congestion_off_threshold(q
))
900 blk_clear_queue_congested(q
, BLK_RW_ASYNC
);
902 blk_queue_for_each_rl(rl
, q
) {
903 if (rl
->count
[BLK_RW_SYNC
] >= q
->nr_requests
) {
904 blk_set_rl_full(rl
, BLK_RW_SYNC
);
906 blk_clear_rl_full(rl
, BLK_RW_SYNC
);
907 wake_up(&rl
->wait
[BLK_RW_SYNC
]);
910 if (rl
->count
[BLK_RW_ASYNC
] >= q
->nr_requests
) {
911 blk_set_rl_full(rl
, BLK_RW_ASYNC
);
913 blk_clear_rl_full(rl
, BLK_RW_ASYNC
);
914 wake_up(&rl
->wait
[BLK_RW_ASYNC
]);
918 spin_unlock_irq(q
->queue_lock
);
923 * Determine if elevator data should be initialized when allocating the
924 * request associated with @bio.
926 static bool blk_rq_should_init_elevator(struct bio
*bio
)
932 * Flush requests do not use the elevator so skip initialization.
933 * This allows a request to share the flush and elevator data.
935 if (bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
))
942 * rq_ioc - determine io_context for request allocation
943 * @bio: request being allocated is for this bio (can be %NULL)
945 * Determine io_context to use for request allocation for @bio. May return
946 * %NULL if %current->io_context doesn't exist.
948 static struct io_context
*rq_ioc(struct bio
*bio
)
950 #ifdef CONFIG_BLK_CGROUP
951 if (bio
&& bio
->bi_ioc
)
954 return current
->io_context
;
958 * __get_request - get a free request
959 * @rl: request list to allocate from
960 * @rw_flags: RW and SYNC flags
961 * @bio: bio to allocate request for (can be %NULL)
962 * @gfp_mask: allocation mask
964 * Get a free request from @q. This function may fail under memory
965 * pressure or if @q is dead.
967 * Must be called with @q->queue_lock held and,
968 * Returns ERR_PTR on failure, with @q->queue_lock held.
969 * Returns request pointer on success, with @q->queue_lock *not held*.
971 static struct request
*__get_request(struct request_list
*rl
, int rw_flags
,
972 struct bio
*bio
, gfp_t gfp_mask
)
974 struct request_queue
*q
= rl
->q
;
976 struct elevator_type
*et
= q
->elevator
->type
;
977 struct io_context
*ioc
= rq_ioc(bio
);
978 struct io_cq
*icq
= NULL
;
979 const bool is_sync
= rw_is_sync(rw_flags
) != 0;
982 if (unlikely(blk_queue_dying(q
)))
983 return ERR_PTR(-ENODEV
);
985 may_queue
= elv_may_queue(q
, rw_flags
);
986 if (may_queue
== ELV_MQUEUE_NO
)
989 if (rl
->count
[is_sync
]+1 >= queue_congestion_on_threshold(q
)) {
990 if (rl
->count
[is_sync
]+1 >= q
->nr_requests
) {
992 * The queue will fill after this allocation, so set
993 * it as full, and mark this process as "batching".
994 * This process will be allowed to complete a batch of
995 * requests, others will be blocked.
997 if (!blk_rl_full(rl
, is_sync
)) {
998 ioc_set_batching(q
, ioc
);
999 blk_set_rl_full(rl
, is_sync
);
1001 if (may_queue
!= ELV_MQUEUE_MUST
1002 && !ioc_batching(q
, ioc
)) {
1004 * The queue is full and the allocating
1005 * process is not a "batcher", and not
1006 * exempted by the IO scheduler
1008 return ERR_PTR(-ENOMEM
);
1013 * bdi isn't aware of blkcg yet. As all async IOs end up
1014 * root blkcg anyway, just use root blkcg state.
1016 if (rl
== &q
->root_rl
)
1017 blk_set_queue_congested(q
, is_sync
);
1021 * Only allow batching queuers to allocate up to 50% over the defined
1022 * limit of requests, otherwise we could have thousands of requests
1023 * allocated with any setting of ->nr_requests
1025 if (rl
->count
[is_sync
] >= (3 * q
->nr_requests
/ 2))
1026 return ERR_PTR(-ENOMEM
);
1028 q
->nr_rqs
[is_sync
]++;
1029 rl
->count
[is_sync
]++;
1030 rl
->starved
[is_sync
] = 0;
1033 * Decide whether the new request will be managed by elevator. If
1034 * so, mark @rw_flags and increment elvpriv. Non-zero elvpriv will
1035 * prevent the current elevator from being destroyed until the new
1036 * request is freed. This guarantees icq's won't be destroyed and
1037 * makes creating new ones safe.
1039 * Also, lookup icq while holding queue_lock. If it doesn't exist,
1040 * it will be created after releasing queue_lock.
1042 if (blk_rq_should_init_elevator(bio
) && !blk_queue_bypass(q
)) {
1043 rw_flags
|= REQ_ELVPRIV
;
1044 q
->nr_rqs_elvpriv
++;
1045 if (et
->icq_cache
&& ioc
)
1046 icq
= ioc_lookup_icq(ioc
, q
);
1049 if (blk_queue_io_stat(q
))
1050 rw_flags
|= REQ_IO_STAT
;
1051 spin_unlock_irq(q
->queue_lock
);
1053 /* allocate and init request */
1054 rq
= mempool_alloc(rl
->rq_pool
, gfp_mask
);
1059 blk_rq_set_rl(rq
, rl
);
1060 rq
->cmd_flags
= rw_flags
| REQ_ALLOCED
;
1063 if (rw_flags
& REQ_ELVPRIV
) {
1064 if (unlikely(et
->icq_cache
&& !icq
)) {
1066 icq
= ioc_create_icq(ioc
, q
, gfp_mask
);
1072 if (unlikely(elv_set_request(q
, rq
, bio
, gfp_mask
)))
1075 /* @rq->elv.icq holds io_context until @rq is freed */
1077 get_io_context(icq
->ioc
);
1081 * ioc may be NULL here, and ioc_batching will be false. That's
1082 * OK, if the queue is under the request limit then requests need
1083 * not count toward the nr_batch_requests limit. There will always
1084 * be some limit enforced by BLK_BATCH_TIME.
1086 if (ioc_batching(q
, ioc
))
1087 ioc
->nr_batch_requests
--;
1089 trace_block_getrq(q
, bio
, rw_flags
& 1);
1094 * elvpriv init failed. ioc, icq and elvpriv aren't mempool backed
1095 * and may fail indefinitely under memory pressure and thus
1096 * shouldn't stall IO. Treat this request as !elvpriv. This will
1097 * disturb iosched and blkcg but weird is bettern than dead.
1099 printk_ratelimited(KERN_WARNING
"%s: dev %s: request aux data allocation failed, iosched may be disturbed\n",
1100 __func__
, dev_name(q
->backing_dev_info
.dev
));
1102 rq
->cmd_flags
&= ~REQ_ELVPRIV
;
1105 spin_lock_irq(q
->queue_lock
);
1106 q
->nr_rqs_elvpriv
--;
1107 spin_unlock_irq(q
->queue_lock
);
1112 * Allocation failed presumably due to memory. Undo anything we
1113 * might have messed up.
1115 * Allocating task should really be put onto the front of the wait
1116 * queue, but this is pretty rare.
1118 spin_lock_irq(q
->queue_lock
);
1119 freed_request(rl
, rw_flags
);
1122 * in the very unlikely event that allocation failed and no
1123 * requests for this direction was pending, mark us starved so that
1124 * freeing of a request in the other direction will notice
1125 * us. another possible fix would be to split the rq mempool into
1129 if (unlikely(rl
->count
[is_sync
] == 0))
1130 rl
->starved
[is_sync
] = 1;
1131 return ERR_PTR(-ENOMEM
);
1135 * get_request - get a free request
1136 * @q: request_queue to allocate request from
1137 * @rw_flags: RW and SYNC flags
1138 * @bio: bio to allocate request for (can be %NULL)
1139 * @gfp_mask: allocation mask
1141 * Get a free request from @q. If %__GFP_WAIT is set in @gfp_mask, this
1142 * function keeps retrying under memory pressure and fails iff @q is dead.
1144 * Must be called with @q->queue_lock held and,
1145 * Returns ERR_PTR on failure, with @q->queue_lock held.
1146 * Returns request pointer on success, with @q->queue_lock *not held*.
1148 static struct request
*get_request(struct request_queue
*q
, int rw_flags
,
1149 struct bio
*bio
, gfp_t gfp_mask
)
1151 const bool is_sync
= rw_is_sync(rw_flags
) != 0;
1153 struct request_list
*rl
;
1156 rl
= blk_get_rl(q
, bio
); /* transferred to @rq on success */
1158 rq
= __get_request(rl
, rw_flags
, bio
, gfp_mask
);
1162 if (!(gfp_mask
& __GFP_WAIT
) || unlikely(blk_queue_dying(q
))) {
1167 /* wait on @rl and retry */
1168 prepare_to_wait_exclusive(&rl
->wait
[is_sync
], &wait
,
1169 TASK_UNINTERRUPTIBLE
);
1171 trace_block_sleeprq(q
, bio
, rw_flags
& 1);
1173 spin_unlock_irq(q
->queue_lock
);
1177 * After sleeping, we become a "batching" process and will be able
1178 * to allocate at least one request, and up to a big batch of them
1179 * for a small period time. See ioc_batching, ioc_set_batching
1181 ioc_set_batching(q
, current
->io_context
);
1183 spin_lock_irq(q
->queue_lock
);
1184 finish_wait(&rl
->wait
[is_sync
], &wait
);
1189 static struct request
*blk_old_get_request(struct request_queue
*q
, int rw
,
1194 BUG_ON(rw
!= READ
&& rw
!= WRITE
);
1196 /* create ioc upfront */
1197 create_io_context(gfp_mask
, q
->node
);
1199 spin_lock_irq(q
->queue_lock
);
1200 rq
= get_request(q
, rw
, NULL
, gfp_mask
);
1202 spin_unlock_irq(q
->queue_lock
);
1203 /* q->queue_lock is unlocked at this point */
1208 struct request
*blk_get_request(struct request_queue
*q
, int rw
, gfp_t gfp_mask
)
1211 return blk_mq_alloc_request(q
, rw
, gfp_mask
, false);
1213 return blk_old_get_request(q
, rw
, gfp_mask
);
1215 EXPORT_SYMBOL(blk_get_request
);
1218 * blk_make_request - given a bio, allocate a corresponding struct request.
1219 * @q: target request queue
1220 * @bio: The bio describing the memory mappings that will be submitted for IO.
1221 * It may be a chained-bio properly constructed by block/bio layer.
1222 * @gfp_mask: gfp flags to be used for memory allocation
1224 * blk_make_request is the parallel of generic_make_request for BLOCK_PC
1225 * type commands. Where the struct request needs to be farther initialized by
1226 * the caller. It is passed a &struct bio, which describes the memory info of
1229 * The caller of blk_make_request must make sure that bi_io_vec
1230 * are set to describe the memory buffers. That bio_data_dir() will return
1231 * the needed direction of the request. (And all bio's in the passed bio-chain
1232 * are properly set accordingly)
1234 * If called under none-sleepable conditions, mapped bio buffers must not
1235 * need bouncing, by calling the appropriate masked or flagged allocator,
1236 * suitable for the target device. Otherwise the call to blk_queue_bounce will
1239 * WARNING: When allocating/cloning a bio-chain, careful consideration should be
1240 * given to how you allocate bios. In particular, you cannot use __GFP_WAIT for
1241 * anything but the first bio in the chain. Otherwise you risk waiting for IO
1242 * completion of a bio that hasn't been submitted yet, thus resulting in a
1243 * deadlock. Alternatively bios should be allocated using bio_kmalloc() instead
1244 * of bio_alloc(), as that avoids the mempool deadlock.
1245 * If possible a big IO should be split into smaller parts when allocation
1246 * fails. Partial allocation should not be an error, or you risk a live-lock.
1248 struct request
*blk_make_request(struct request_queue
*q
, struct bio
*bio
,
1251 struct request
*rq
= blk_get_request(q
, bio_data_dir(bio
), gfp_mask
);
1256 blk_rq_set_block_pc(rq
);
1259 struct bio
*bounce_bio
= bio
;
1262 blk_queue_bounce(q
, &bounce_bio
);
1263 ret
= blk_rq_append_bio(q
, rq
, bounce_bio
);
1264 if (unlikely(ret
)) {
1265 blk_put_request(rq
);
1266 return ERR_PTR(ret
);
1272 EXPORT_SYMBOL(blk_make_request
);
1275 * blk_rq_set_block_pc - initialize a request to type BLOCK_PC
1276 * @rq: request to be initialized
1279 void blk_rq_set_block_pc(struct request
*rq
)
1281 rq
->cmd_type
= REQ_TYPE_BLOCK_PC
;
1283 rq
->__sector
= (sector_t
) -1;
1284 rq
->bio
= rq
->biotail
= NULL
;
1285 memset(rq
->__cmd
, 0, sizeof(rq
->__cmd
));
1287 EXPORT_SYMBOL(blk_rq_set_block_pc
);
1290 * blk_requeue_request - put a request back on queue
1291 * @q: request queue where request should be inserted
1292 * @rq: request to be inserted
1295 * Drivers often keep queueing requests until the hardware cannot accept
1296 * more, when that condition happens we need to put the request back
1297 * on the queue. Must be called with queue lock held.
1299 void blk_requeue_request(struct request_queue
*q
, struct request
*rq
)
1301 blk_delete_timer(rq
);
1302 blk_clear_rq_complete(rq
);
1303 trace_block_rq_requeue(q
, rq
);
1305 if (rq
->cmd_flags
& REQ_QUEUED
)
1306 blk_queue_end_tag(q
, rq
);
1308 BUG_ON(blk_queued_rq(rq
));
1310 elv_requeue_request(q
, rq
);
1312 EXPORT_SYMBOL(blk_requeue_request
);
1314 static void add_acct_request(struct request_queue
*q
, struct request
*rq
,
1317 blk_account_io_start(rq
, true);
1318 __elv_add_request(q
, rq
, where
);
1321 static void part_round_stats_single(int cpu
, struct hd_struct
*part
,
1326 if (now
== part
->stamp
)
1329 inflight
= part_in_flight(part
);
1331 __part_stat_add(cpu
, part
, time_in_queue
,
1332 inflight
* (now
- part
->stamp
));
1333 __part_stat_add(cpu
, part
, io_ticks
, (now
- part
->stamp
));
1339 * part_round_stats() - Round off the performance stats on a struct disk_stats.
1340 * @cpu: cpu number for stats access
1341 * @part: target partition
1343 * The average IO queue length and utilisation statistics are maintained
1344 * by observing the current state of the queue length and the amount of
1345 * time it has been in this state for.
1347 * Normally, that accounting is done on IO completion, but that can result
1348 * in more than a second's worth of IO being accounted for within any one
1349 * second, leading to >100% utilisation. To deal with that, we call this
1350 * function to do a round-off before returning the results when reading
1351 * /proc/diskstats. This accounts immediately for all queue usage up to
1352 * the current jiffies and restarts the counters again.
1354 void part_round_stats(int cpu
, struct hd_struct
*part
)
1356 unsigned long now
= jiffies
;
1359 part_round_stats_single(cpu
, &part_to_disk(part
)->part0
, now
);
1360 part_round_stats_single(cpu
, part
, now
);
1362 EXPORT_SYMBOL_GPL(part_round_stats
);
1365 static void blk_pm_put_request(struct request
*rq
)
1367 if (rq
->q
->dev
&& !(rq
->cmd_flags
& REQ_PM
) && !--rq
->q
->nr_pending
)
1368 pm_runtime_mark_last_busy(rq
->q
->dev
);
1371 static inline void blk_pm_put_request(struct request
*rq
) {}
1375 * queue lock must be held
1377 void __blk_put_request(struct request_queue
*q
, struct request
*req
)
1383 blk_mq_free_request(req
);
1387 blk_pm_put_request(req
);
1389 elv_completed_request(q
, req
);
1391 /* this is a bio leak */
1392 WARN_ON(req
->bio
!= NULL
);
1395 * Request may not have originated from ll_rw_blk. if not,
1396 * it didn't come out of our reserved rq pools
1398 if (req
->cmd_flags
& REQ_ALLOCED
) {
1399 unsigned int flags
= req
->cmd_flags
;
1400 struct request_list
*rl
= blk_rq_rl(req
);
1402 BUG_ON(!list_empty(&req
->queuelist
));
1403 BUG_ON(ELV_ON_HASH(req
));
1405 blk_free_request(rl
, req
);
1406 freed_request(rl
, flags
);
1410 EXPORT_SYMBOL_GPL(__blk_put_request
);
1412 void blk_put_request(struct request
*req
)
1414 struct request_queue
*q
= req
->q
;
1417 blk_mq_free_request(req
);
1419 unsigned long flags
;
1421 spin_lock_irqsave(q
->queue_lock
, flags
);
1422 __blk_put_request(q
, req
);
1423 spin_unlock_irqrestore(q
->queue_lock
, flags
);
1426 EXPORT_SYMBOL(blk_put_request
);
1429 * blk_add_request_payload - add a payload to a request
1430 * @rq: request to update
1431 * @page: page backing the payload
1432 * @len: length of the payload.
1434 * This allows to later add a payload to an already submitted request by
1435 * a block driver. The driver needs to take care of freeing the payload
1438 * Note that this is a quite horrible hack and nothing but handling of
1439 * discard requests should ever use it.
1441 void blk_add_request_payload(struct request
*rq
, struct page
*page
,
1444 struct bio
*bio
= rq
->bio
;
1446 bio
->bi_io_vec
->bv_page
= page
;
1447 bio
->bi_io_vec
->bv_offset
= 0;
1448 bio
->bi_io_vec
->bv_len
= len
;
1450 bio
->bi_iter
.bi_size
= len
;
1452 bio
->bi_phys_segments
= 1;
1454 rq
->__data_len
= rq
->resid_len
= len
;
1455 rq
->nr_phys_segments
= 1;
1457 EXPORT_SYMBOL_GPL(blk_add_request_payload
);
1459 bool bio_attempt_back_merge(struct request_queue
*q
, struct request
*req
,
1462 const int ff
= bio
->bi_rw
& REQ_FAILFAST_MASK
;
1464 if (!ll_back_merge_fn(q
, req
, bio
))
1467 trace_block_bio_backmerge(q
, req
, bio
);
1469 if ((req
->cmd_flags
& REQ_FAILFAST_MASK
) != ff
)
1470 blk_rq_set_mixed_merge(req
);
1472 req
->biotail
->bi_next
= bio
;
1474 req
->__data_len
+= bio
->bi_iter
.bi_size
;
1475 req
->ioprio
= ioprio_best(req
->ioprio
, bio_prio(bio
));
1477 blk_account_io_start(req
, false);
1481 bool bio_attempt_front_merge(struct request_queue
*q
, struct request
*req
,
1484 const int ff
= bio
->bi_rw
& REQ_FAILFAST_MASK
;
1486 if (!ll_front_merge_fn(q
, req
, bio
))
1489 trace_block_bio_frontmerge(q
, req
, bio
);
1491 if ((req
->cmd_flags
& REQ_FAILFAST_MASK
) != ff
)
1492 blk_rq_set_mixed_merge(req
);
1494 bio
->bi_next
= req
->bio
;
1497 req
->__sector
= bio
->bi_iter
.bi_sector
;
1498 req
->__data_len
+= bio
->bi_iter
.bi_size
;
1499 req
->ioprio
= ioprio_best(req
->ioprio
, bio_prio(bio
));
1501 blk_account_io_start(req
, false);
1506 * blk_attempt_plug_merge - try to merge with %current's plugged list
1507 * @q: request_queue new bio is being queued at
1508 * @bio: new bio being queued
1509 * @request_count: out parameter for number of traversed plugged requests
1511 * Determine whether @bio being queued on @q can be merged with a request
1512 * on %current's plugged list. Returns %true if merge was successful,
1515 * Plugging coalesces IOs from the same issuer for the same purpose without
1516 * going through @q->queue_lock. As such it's more of an issuing mechanism
1517 * than scheduling, and the request, while may have elvpriv data, is not
1518 * added on the elevator at this point. In addition, we don't have
1519 * reliable access to the elevator outside queue lock. Only check basic
1520 * merging parameters without querying the elevator.
1522 * Caller must ensure !blk_queue_nomerges(q) beforehand.
1524 bool blk_attempt_plug_merge(struct request_queue
*q
, struct bio
*bio
,
1525 unsigned int *request_count
)
1527 struct blk_plug
*plug
;
1530 struct list_head
*plug_list
;
1532 plug
= current
->plug
;
1538 plug_list
= &plug
->mq_list
;
1540 plug_list
= &plug
->list
;
1542 list_for_each_entry_reverse(rq
, plug_list
, queuelist
) {
1548 if (rq
->q
!= q
|| !blk_rq_merge_ok(rq
, bio
))
1551 el_ret
= blk_try_merge(rq
, bio
);
1552 if (el_ret
== ELEVATOR_BACK_MERGE
) {
1553 ret
= bio_attempt_back_merge(q
, rq
, bio
);
1556 } else if (el_ret
== ELEVATOR_FRONT_MERGE
) {
1557 ret
= bio_attempt_front_merge(q
, rq
, bio
);
1566 void init_request_from_bio(struct request
*req
, struct bio
*bio
)
1568 req
->cmd_type
= REQ_TYPE_FS
;
1570 req
->cmd_flags
|= bio
->bi_rw
& REQ_COMMON_MASK
;
1571 if (bio
->bi_rw
& REQ_RAHEAD
)
1572 req
->cmd_flags
|= REQ_FAILFAST_MASK
;
1575 req
->__sector
= bio
->bi_iter
.bi_sector
;
1576 req
->ioprio
= bio_prio(bio
);
1577 blk_rq_bio_prep(req
->q
, req
, bio
);
1580 void blk_queue_bio(struct request_queue
*q
, struct bio
*bio
)
1582 const bool sync
= !!(bio
->bi_rw
& REQ_SYNC
);
1583 struct blk_plug
*plug
;
1584 int el_ret
, rw_flags
, where
= ELEVATOR_INSERT_SORT
;
1585 struct request
*req
;
1586 unsigned int request_count
= 0;
1589 * low level driver can indicate that it wants pages above a
1590 * certain limit bounced to low memory (ie for highmem, or even
1591 * ISA dma in theory)
1593 blk_queue_bounce(q
, &bio
);
1595 if (bio_integrity_enabled(bio
) && bio_integrity_prep(bio
)) {
1596 bio_endio(bio
, -EIO
);
1600 if (bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
)) {
1601 spin_lock_irq(q
->queue_lock
);
1602 where
= ELEVATOR_INSERT_FLUSH
;
1607 * Check if we can merge with the plugged list before grabbing
1610 if (!blk_queue_nomerges(q
) &&
1611 blk_attempt_plug_merge(q
, bio
, &request_count
))
1614 spin_lock_irq(q
->queue_lock
);
1616 el_ret
= elv_merge(q
, &req
, bio
);
1617 if (el_ret
== ELEVATOR_BACK_MERGE
) {
1618 if (bio_attempt_back_merge(q
, req
, bio
)) {
1619 elv_bio_merged(q
, req
, bio
);
1620 if (!attempt_back_merge(q
, req
))
1621 elv_merged_request(q
, req
, el_ret
);
1624 } else if (el_ret
== ELEVATOR_FRONT_MERGE
) {
1625 if (bio_attempt_front_merge(q
, req
, bio
)) {
1626 elv_bio_merged(q
, req
, bio
);
1627 if (!attempt_front_merge(q
, req
))
1628 elv_merged_request(q
, req
, el_ret
);
1635 * This sync check and mask will be re-done in init_request_from_bio(),
1636 * but we need to set it earlier to expose the sync flag to the
1637 * rq allocator and io schedulers.
1639 rw_flags
= bio_data_dir(bio
);
1641 rw_flags
|= REQ_SYNC
;
1644 * Grab a free request. This is might sleep but can not fail.
1645 * Returns with the queue unlocked.
1647 req
= get_request(q
, rw_flags
, bio
, GFP_NOIO
);
1649 bio_endio(bio
, PTR_ERR(req
)); /* @q is dead */
1654 * After dropping the lock and possibly sleeping here, our request
1655 * may now be mergeable after it had proven unmergeable (above).
1656 * We don't worry about that case for efficiency. It won't happen
1657 * often, and the elevators are able to handle it.
1659 init_request_from_bio(req
, bio
);
1661 if (test_bit(QUEUE_FLAG_SAME_COMP
, &q
->queue_flags
))
1662 req
->cpu
= raw_smp_processor_id();
1664 plug
= current
->plug
;
1667 * If this is the first request added after a plug, fire
1671 trace_block_plug(q
);
1673 if (request_count
>= BLK_MAX_REQUEST_COUNT
) {
1674 blk_flush_plug_list(plug
, false);
1675 trace_block_plug(q
);
1678 list_add_tail(&req
->queuelist
, &plug
->list
);
1679 blk_account_io_start(req
, true);
1681 spin_lock_irq(q
->queue_lock
);
1682 add_acct_request(q
, req
, where
);
1685 spin_unlock_irq(q
->queue_lock
);
1688 EXPORT_SYMBOL_GPL(blk_queue_bio
); /* for device mapper only */
1691 * If bio->bi_dev is a partition, remap the location
1693 static inline void blk_partition_remap(struct bio
*bio
)
1695 struct block_device
*bdev
= bio
->bi_bdev
;
1697 if (bio_sectors(bio
) && bdev
!= bdev
->bd_contains
) {
1698 struct hd_struct
*p
= bdev
->bd_part
;
1700 bio
->bi_iter
.bi_sector
+= p
->start_sect
;
1701 bio
->bi_bdev
= bdev
->bd_contains
;
1703 trace_block_bio_remap(bdev_get_queue(bio
->bi_bdev
), bio
,
1705 bio
->bi_iter
.bi_sector
- p
->start_sect
);
1709 static void handle_bad_sector(struct bio
*bio
)
1711 char b
[BDEVNAME_SIZE
];
1713 printk(KERN_INFO
"attempt to access beyond end of device\n");
1714 printk(KERN_INFO
"%s: rw=%ld, want=%Lu, limit=%Lu\n",
1715 bdevname(bio
->bi_bdev
, b
),
1717 (unsigned long long)bio_end_sector(bio
),
1718 (long long)(i_size_read(bio
->bi_bdev
->bd_inode
) >> 9));
1720 set_bit(BIO_EOF
, &bio
->bi_flags
);
1723 #ifdef CONFIG_FAIL_MAKE_REQUEST
1725 static DECLARE_FAULT_ATTR(fail_make_request
);
1727 static int __init
setup_fail_make_request(char *str
)
1729 return setup_fault_attr(&fail_make_request
, str
);
1731 __setup("fail_make_request=", setup_fail_make_request
);
1733 static bool should_fail_request(struct hd_struct
*part
, unsigned int bytes
)
1735 return part
->make_it_fail
&& should_fail(&fail_make_request
, bytes
);
1738 static int __init
fail_make_request_debugfs(void)
1740 struct dentry
*dir
= fault_create_debugfs_attr("fail_make_request",
1741 NULL
, &fail_make_request
);
1743 return PTR_ERR_OR_ZERO(dir
);
1746 late_initcall(fail_make_request_debugfs
);
1748 #else /* CONFIG_FAIL_MAKE_REQUEST */
1750 static inline bool should_fail_request(struct hd_struct
*part
,
1756 #endif /* CONFIG_FAIL_MAKE_REQUEST */
1759 * Check whether this bio extends beyond the end of the device.
1761 static inline int bio_check_eod(struct bio
*bio
, unsigned int nr_sectors
)
1768 /* Test device or partition size, when known. */
1769 maxsector
= i_size_read(bio
->bi_bdev
->bd_inode
) >> 9;
1771 sector_t sector
= bio
->bi_iter
.bi_sector
;
1773 if (maxsector
< nr_sectors
|| maxsector
- nr_sectors
< sector
) {
1775 * This may well happen - the kernel calls bread()
1776 * without checking the size of the device, e.g., when
1777 * mounting a device.
1779 handle_bad_sector(bio
);
1787 static noinline_for_stack
bool
1788 generic_make_request_checks(struct bio
*bio
)
1790 struct request_queue
*q
;
1791 int nr_sectors
= bio_sectors(bio
);
1793 char b
[BDEVNAME_SIZE
];
1794 struct hd_struct
*part
;
1798 if (bio_check_eod(bio
, nr_sectors
))
1801 q
= bdev_get_queue(bio
->bi_bdev
);
1804 "generic_make_request: Trying to access "
1805 "nonexistent block-device %s (%Lu)\n",
1806 bdevname(bio
->bi_bdev
, b
),
1807 (long long) bio
->bi_iter
.bi_sector
);
1811 if (likely(bio_is_rw(bio
) &&
1812 nr_sectors
> queue_max_hw_sectors(q
))) {
1813 printk(KERN_ERR
"bio too big device %s (%u > %u)\n",
1814 bdevname(bio
->bi_bdev
, b
),
1816 queue_max_hw_sectors(q
));
1820 part
= bio
->bi_bdev
->bd_part
;
1821 if (should_fail_request(part
, bio
->bi_iter
.bi_size
) ||
1822 should_fail_request(&part_to_disk(part
)->part0
,
1823 bio
->bi_iter
.bi_size
))
1827 * If this device has partitions, remap block n
1828 * of partition p to block n+start(p) of the disk.
1830 blk_partition_remap(bio
);
1832 if (bio_check_eod(bio
, nr_sectors
))
1836 * Filter flush bio's early so that make_request based
1837 * drivers without flush support don't have to worry
1840 if ((bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
)) && !q
->flush_flags
) {
1841 bio
->bi_rw
&= ~(REQ_FLUSH
| REQ_FUA
);
1848 if ((bio
->bi_rw
& REQ_DISCARD
) &&
1849 (!blk_queue_discard(q
) ||
1850 ((bio
->bi_rw
& REQ_SECURE
) && !blk_queue_secdiscard(q
)))) {
1855 if (bio
->bi_rw
& REQ_WRITE_SAME
&& !bdev_write_same(bio
->bi_bdev
)) {
1861 * Various block parts want %current->io_context and lazy ioc
1862 * allocation ends up trading a lot of pain for a small amount of
1863 * memory. Just allocate it upfront. This may fail and block
1864 * layer knows how to live with it.
1866 create_io_context(GFP_ATOMIC
, q
->node
);
1868 if (blk_throtl_bio(q
, bio
))
1869 return false; /* throttled, will be resubmitted later */
1871 trace_block_bio_queue(q
, bio
);
1875 bio_endio(bio
, err
);
1880 * generic_make_request - hand a buffer to its device driver for I/O
1881 * @bio: The bio describing the location in memory and on the device.
1883 * generic_make_request() is used to make I/O requests of block
1884 * devices. It is passed a &struct bio, which describes the I/O that needs
1887 * generic_make_request() does not return any status. The
1888 * success/failure status of the request, along with notification of
1889 * completion, is delivered asynchronously through the bio->bi_end_io
1890 * function described (one day) else where.
1892 * The caller of generic_make_request must make sure that bi_io_vec
1893 * are set to describe the memory buffer, and that bi_dev and bi_sector are
1894 * set to describe the device address, and the
1895 * bi_end_io and optionally bi_private are set to describe how
1896 * completion notification should be signaled.
1898 * generic_make_request and the drivers it calls may use bi_next if this
1899 * bio happens to be merged with someone else, and may resubmit the bio to
1900 * a lower device by calling into generic_make_request recursively, which
1901 * means the bio should NOT be touched after the call to ->make_request_fn.
1903 void generic_make_request(struct bio
*bio
)
1905 struct bio_list bio_list_on_stack
;
1907 if (!generic_make_request_checks(bio
))
1911 * We only want one ->make_request_fn to be active at a time, else
1912 * stack usage with stacked devices could be a problem. So use
1913 * current->bio_list to keep a list of requests submited by a
1914 * make_request_fn function. current->bio_list is also used as a
1915 * flag to say if generic_make_request is currently active in this
1916 * task or not. If it is NULL, then no make_request is active. If
1917 * it is non-NULL, then a make_request is active, and new requests
1918 * should be added at the tail
1920 if (current
->bio_list
) {
1921 bio_list_add(current
->bio_list
, bio
);
1925 /* following loop may be a bit non-obvious, and so deserves some
1927 * Before entering the loop, bio->bi_next is NULL (as all callers
1928 * ensure that) so we have a list with a single bio.
1929 * We pretend that we have just taken it off a longer list, so
1930 * we assign bio_list to a pointer to the bio_list_on_stack,
1931 * thus initialising the bio_list of new bios to be
1932 * added. ->make_request() may indeed add some more bios
1933 * through a recursive call to generic_make_request. If it
1934 * did, we find a non-NULL value in bio_list and re-enter the loop
1935 * from the top. In this case we really did just take the bio
1936 * of the top of the list (no pretending) and so remove it from
1937 * bio_list, and call into ->make_request() again.
1939 BUG_ON(bio
->bi_next
);
1940 bio_list_init(&bio_list_on_stack
);
1941 current
->bio_list
= &bio_list_on_stack
;
1943 struct request_queue
*q
= bdev_get_queue(bio
->bi_bdev
);
1945 q
->make_request_fn(q
, bio
);
1947 bio
= bio_list_pop(current
->bio_list
);
1949 current
->bio_list
= NULL
; /* deactivate */
1951 EXPORT_SYMBOL(generic_make_request
);
1954 * submit_bio - submit a bio to the block device layer for I/O
1955 * @rw: whether to %READ or %WRITE, or maybe to %READA (read ahead)
1956 * @bio: The &struct bio which describes the I/O
1958 * submit_bio() is very similar in purpose to generic_make_request(), and
1959 * uses that function to do most of the work. Both are fairly rough
1960 * interfaces; @bio must be presetup and ready for I/O.
1963 void submit_bio(int rw
, struct bio
*bio
)
1968 * If it's a regular read/write or a barrier with data attached,
1969 * go through the normal accounting stuff before submission.
1971 if (bio_has_data(bio
)) {
1974 if (unlikely(rw
& REQ_WRITE_SAME
))
1975 count
= bdev_logical_block_size(bio
->bi_bdev
) >> 9;
1977 count
= bio_sectors(bio
);
1980 count_vm_events(PGPGOUT
, count
);
1982 task_io_account_read(bio
->bi_iter
.bi_size
);
1983 count_vm_events(PGPGIN
, count
);
1986 if (unlikely(block_dump
)) {
1987 char b
[BDEVNAME_SIZE
];
1988 printk(KERN_DEBUG
"%s(%d): %s block %Lu on %s (%u sectors)\n",
1989 current
->comm
, task_pid_nr(current
),
1990 (rw
& WRITE
) ? "WRITE" : "READ",
1991 (unsigned long long)bio
->bi_iter
.bi_sector
,
1992 bdevname(bio
->bi_bdev
, b
),
1997 generic_make_request(bio
);
1999 EXPORT_SYMBOL(submit_bio
);
2002 * blk_rq_check_limits - Helper function to check a request for the queue limit
2004 * @rq: the request being checked
2007 * @rq may have been made based on weaker limitations of upper-level queues
2008 * in request stacking drivers, and it may violate the limitation of @q.
2009 * Since the block layer and the underlying device driver trust @rq
2010 * after it is inserted to @q, it should be checked against @q before
2011 * the insertion using this generic function.
2013 * This function should also be useful for request stacking drivers
2014 * in some cases below, so export this function.
2015 * Request stacking drivers like request-based dm may change the queue
2016 * limits while requests are in the queue (e.g. dm's table swapping).
2017 * Such request stacking drivers should check those requests against
2018 * the new queue limits again when they dispatch those requests,
2019 * although such checkings are also done against the old queue limits
2020 * when submitting requests.
2022 int blk_rq_check_limits(struct request_queue
*q
, struct request
*rq
)
2024 if (!rq_mergeable(rq
))
2027 if (blk_rq_sectors(rq
) > blk_queue_get_max_sectors(q
, rq
->cmd_flags
)) {
2028 printk(KERN_ERR
"%s: over max size limit.\n", __func__
);
2033 * queue's settings related to segment counting like q->bounce_pfn
2034 * may differ from that of other stacking queues.
2035 * Recalculate it to check the request correctly on this queue's
2038 blk_recalc_rq_segments(rq
);
2039 if (rq
->nr_phys_segments
> queue_max_segments(q
)) {
2040 printk(KERN_ERR
"%s: over max segments limit.\n", __func__
);
2046 EXPORT_SYMBOL_GPL(blk_rq_check_limits
);
2049 * blk_insert_cloned_request - Helper for stacking drivers to submit a request
2050 * @q: the queue to submit the request
2051 * @rq: the request being queued
2053 int blk_insert_cloned_request(struct request_queue
*q
, struct request
*rq
)
2055 unsigned long flags
;
2056 int where
= ELEVATOR_INSERT_BACK
;
2058 if (blk_rq_check_limits(q
, rq
))
2062 should_fail_request(&rq
->rq_disk
->part0
, blk_rq_bytes(rq
)))
2066 if (blk_queue_io_stat(q
))
2067 blk_account_io_start(rq
, true);
2068 blk_mq_insert_request(rq
, false, true, true);
2072 spin_lock_irqsave(q
->queue_lock
, flags
);
2073 if (unlikely(blk_queue_dying(q
))) {
2074 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2079 * Submitting request must be dequeued before calling this function
2080 * because it will be linked to another request_queue
2082 BUG_ON(blk_queued_rq(rq
));
2084 if (rq
->cmd_flags
& (REQ_FLUSH
|REQ_FUA
))
2085 where
= ELEVATOR_INSERT_FLUSH
;
2087 add_acct_request(q
, rq
, where
);
2088 if (where
== ELEVATOR_INSERT_FLUSH
)
2090 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2094 EXPORT_SYMBOL_GPL(blk_insert_cloned_request
);
2097 * blk_rq_err_bytes - determine number of bytes till the next failure boundary
2098 * @rq: request to examine
2101 * A request could be merge of IOs which require different failure
2102 * handling. This function determines the number of bytes which
2103 * can be failed from the beginning of the request without
2104 * crossing into area which need to be retried further.
2107 * The number of bytes to fail.
2110 * queue_lock must be held.
2112 unsigned int blk_rq_err_bytes(const struct request
*rq
)
2114 unsigned int ff
= rq
->cmd_flags
& REQ_FAILFAST_MASK
;
2115 unsigned int bytes
= 0;
2118 if (!(rq
->cmd_flags
& REQ_MIXED_MERGE
))
2119 return blk_rq_bytes(rq
);
2122 * Currently the only 'mixing' which can happen is between
2123 * different fastfail types. We can safely fail portions
2124 * which have all the failfast bits that the first one has -
2125 * the ones which are at least as eager to fail as the first
2128 for (bio
= rq
->bio
; bio
; bio
= bio
->bi_next
) {
2129 if ((bio
->bi_rw
& ff
) != ff
)
2131 bytes
+= bio
->bi_iter
.bi_size
;
2134 /* this could lead to infinite loop */
2135 BUG_ON(blk_rq_bytes(rq
) && !bytes
);
2138 EXPORT_SYMBOL_GPL(blk_rq_err_bytes
);
2140 void blk_account_io_completion(struct request
*req
, unsigned int bytes
)
2142 if (blk_do_io_stat(req
)) {
2143 const int rw
= rq_data_dir(req
);
2144 struct hd_struct
*part
;
2147 cpu
= part_stat_lock();
2149 part_stat_add(cpu
, part
, sectors
[rw
], bytes
>> 9);
2154 void blk_account_io_done(struct request
*req
)
2157 * Account IO completion. flush_rq isn't accounted as a
2158 * normal IO on queueing nor completion. Accounting the
2159 * containing request is enough.
2161 if (blk_do_io_stat(req
) && !(req
->cmd_flags
& REQ_FLUSH_SEQ
)) {
2162 unsigned long duration
= jiffies
- req
->start_time
;
2163 const int rw
= rq_data_dir(req
);
2164 struct hd_struct
*part
;
2167 cpu
= part_stat_lock();
2170 part_stat_inc(cpu
, part
, ios
[rw
]);
2171 part_stat_add(cpu
, part
, ticks
[rw
], duration
);
2172 part_round_stats(cpu
, part
);
2173 part_dec_in_flight(part
, rw
);
2175 hd_struct_put(part
);
2182 * Don't process normal requests when queue is suspended
2183 * or in the process of suspending/resuming
2185 static struct request
*blk_pm_peek_request(struct request_queue
*q
,
2188 if (q
->dev
&& (q
->rpm_status
== RPM_SUSPENDED
||
2189 (q
->rpm_status
!= RPM_ACTIVE
&& !(rq
->cmd_flags
& REQ_PM
))))
2195 static inline struct request
*blk_pm_peek_request(struct request_queue
*q
,
2202 void blk_account_io_start(struct request
*rq
, bool new_io
)
2204 struct hd_struct
*part
;
2205 int rw
= rq_data_dir(rq
);
2208 if (!blk_do_io_stat(rq
))
2211 cpu
= part_stat_lock();
2215 part_stat_inc(cpu
, part
, merges
[rw
]);
2217 part
= disk_map_sector_rcu(rq
->rq_disk
, blk_rq_pos(rq
));
2218 if (!hd_struct_try_get(part
)) {
2220 * The partition is already being removed,
2221 * the request will be accounted on the disk only
2223 * We take a reference on disk->part0 although that
2224 * partition will never be deleted, so we can treat
2225 * it as any other partition.
2227 part
= &rq
->rq_disk
->part0
;
2228 hd_struct_get(part
);
2230 part_round_stats(cpu
, part
);
2231 part_inc_in_flight(part
, rw
);
2239 * blk_peek_request - peek at the top of a request queue
2240 * @q: request queue to peek at
2243 * Return the request at the top of @q. The returned request
2244 * should be started using blk_start_request() before LLD starts
2248 * Pointer to the request at the top of @q if available. Null
2252 * queue_lock must be held.
2254 struct request
*blk_peek_request(struct request_queue
*q
)
2259 while ((rq
= __elv_next_request(q
)) != NULL
) {
2261 rq
= blk_pm_peek_request(q
, rq
);
2265 if (!(rq
->cmd_flags
& REQ_STARTED
)) {
2267 * This is the first time the device driver
2268 * sees this request (possibly after
2269 * requeueing). Notify IO scheduler.
2271 if (rq
->cmd_flags
& REQ_SORTED
)
2272 elv_activate_rq(q
, rq
);
2275 * just mark as started even if we don't start
2276 * it, a request that has been delayed should
2277 * not be passed by new incoming requests
2279 rq
->cmd_flags
|= REQ_STARTED
;
2280 trace_block_rq_issue(q
, rq
);
2283 if (!q
->boundary_rq
|| q
->boundary_rq
== rq
) {
2284 q
->end_sector
= rq_end_sector(rq
);
2285 q
->boundary_rq
= NULL
;
2288 if (rq
->cmd_flags
& REQ_DONTPREP
)
2291 if (q
->dma_drain_size
&& blk_rq_bytes(rq
)) {
2293 * make sure space for the drain appears we
2294 * know we can do this because max_hw_segments
2295 * has been adjusted to be one fewer than the
2298 rq
->nr_phys_segments
++;
2304 ret
= q
->prep_rq_fn(q
, rq
);
2305 if (ret
== BLKPREP_OK
) {
2307 } else if (ret
== BLKPREP_DEFER
) {
2309 * the request may have been (partially) prepped.
2310 * we need to keep this request in the front to
2311 * avoid resource deadlock. REQ_STARTED will
2312 * prevent other fs requests from passing this one.
2314 if (q
->dma_drain_size
&& blk_rq_bytes(rq
) &&
2315 !(rq
->cmd_flags
& REQ_DONTPREP
)) {
2317 * remove the space for the drain we added
2318 * so that we don't add it again
2320 --rq
->nr_phys_segments
;
2325 } else if (ret
== BLKPREP_KILL
) {
2326 rq
->cmd_flags
|= REQ_QUIET
;
2328 * Mark this request as started so we don't trigger
2329 * any debug logic in the end I/O path.
2331 blk_start_request(rq
);
2332 __blk_end_request_all(rq
, -EIO
);
2334 printk(KERN_ERR
"%s: bad return=%d\n", __func__
, ret
);
2341 EXPORT_SYMBOL(blk_peek_request
);
2343 void blk_dequeue_request(struct request
*rq
)
2345 struct request_queue
*q
= rq
->q
;
2347 BUG_ON(list_empty(&rq
->queuelist
));
2348 BUG_ON(ELV_ON_HASH(rq
));
2350 list_del_init(&rq
->queuelist
);
2353 * the time frame between a request being removed from the lists
2354 * and to it is freed is accounted as io that is in progress at
2357 if (blk_account_rq(rq
)) {
2358 q
->in_flight
[rq_is_sync(rq
)]++;
2359 set_io_start_time_ns(rq
);
2364 * blk_start_request - start request processing on the driver
2365 * @req: request to dequeue
2368 * Dequeue @req and start timeout timer on it. This hands off the
2369 * request to the driver.
2371 * Block internal functions which don't want to start timer should
2372 * call blk_dequeue_request().
2375 * queue_lock must be held.
2377 void blk_start_request(struct request
*req
)
2379 blk_dequeue_request(req
);
2382 * We are now handing the request to the hardware, initialize
2383 * resid_len to full count and add the timeout handler.
2385 req
->resid_len
= blk_rq_bytes(req
);
2386 if (unlikely(blk_bidi_rq(req
)))
2387 req
->next_rq
->resid_len
= blk_rq_bytes(req
->next_rq
);
2389 BUG_ON(test_bit(REQ_ATOM_COMPLETE
, &req
->atomic_flags
));
2392 EXPORT_SYMBOL(blk_start_request
);
2395 * blk_fetch_request - fetch a request from a request queue
2396 * @q: request queue to fetch a request from
2399 * Return the request at the top of @q. The request is started on
2400 * return and LLD can start processing it immediately.
2403 * Pointer to the request at the top of @q if available. Null
2407 * queue_lock must be held.
2409 struct request
*blk_fetch_request(struct request_queue
*q
)
2413 rq
= blk_peek_request(q
);
2415 blk_start_request(rq
);
2418 EXPORT_SYMBOL(blk_fetch_request
);
2421 * blk_update_request - Special helper function for request stacking drivers
2422 * @req: the request being processed
2423 * @error: %0 for success, < %0 for error
2424 * @nr_bytes: number of bytes to complete @req
2427 * Ends I/O on a number of bytes attached to @req, but doesn't complete
2428 * the request structure even if @req doesn't have leftover.
2429 * If @req has leftover, sets it up for the next range of segments.
2431 * This special helper function is only for request stacking drivers
2432 * (e.g. request-based dm) so that they can handle partial completion.
2433 * Actual device drivers should use blk_end_request instead.
2435 * Passing the result of blk_rq_bytes() as @nr_bytes guarantees
2436 * %false return from this function.
2439 * %false - this request doesn't have any more data
2440 * %true - this request has more data
2442 bool blk_update_request(struct request
*req
, int error
, unsigned int nr_bytes
)
2446 trace_block_rq_complete(req
->q
, req
, nr_bytes
);
2452 * For fs requests, rq is just carrier of independent bio's
2453 * and each partial completion should be handled separately.
2454 * Reset per-request error on each partial completion.
2456 * TODO: tj: This is too subtle. It would be better to let
2457 * low level drivers do what they see fit.
2459 if (req
->cmd_type
== REQ_TYPE_FS
)
2462 if (error
&& req
->cmd_type
== REQ_TYPE_FS
&&
2463 !(req
->cmd_flags
& REQ_QUIET
)) {
2468 error_type
= "recoverable transport";
2471 error_type
= "critical target";
2474 error_type
= "critical nexus";
2477 error_type
= "timeout";
2480 error_type
= "critical space allocation";
2483 error_type
= "critical medium";
2490 printk_ratelimited(KERN_ERR
"%s: %s error, dev %s, sector %llu\n",
2491 __func__
, error_type
, req
->rq_disk
?
2492 req
->rq_disk
->disk_name
: "?",
2493 (unsigned long long)blk_rq_pos(req
));
2497 blk_account_io_completion(req
, nr_bytes
);
2501 struct bio
*bio
= req
->bio
;
2502 unsigned bio_bytes
= min(bio
->bi_iter
.bi_size
, nr_bytes
);
2504 if (bio_bytes
== bio
->bi_iter
.bi_size
)
2505 req
->bio
= bio
->bi_next
;
2507 req_bio_endio(req
, bio
, bio_bytes
, error
);
2509 total_bytes
+= bio_bytes
;
2510 nr_bytes
-= bio_bytes
;
2521 * Reset counters so that the request stacking driver
2522 * can find how many bytes remain in the request
2525 req
->__data_len
= 0;
2529 req
->__data_len
-= total_bytes
;
2531 /* update sector only for requests with clear definition of sector */
2532 if (req
->cmd_type
== REQ_TYPE_FS
)
2533 req
->__sector
+= total_bytes
>> 9;
2535 /* mixed attributes always follow the first bio */
2536 if (req
->cmd_flags
& REQ_MIXED_MERGE
) {
2537 req
->cmd_flags
&= ~REQ_FAILFAST_MASK
;
2538 req
->cmd_flags
|= req
->bio
->bi_rw
& REQ_FAILFAST_MASK
;
2542 * If total number of sectors is less than the first segment
2543 * size, something has gone terribly wrong.
2545 if (blk_rq_bytes(req
) < blk_rq_cur_bytes(req
)) {
2546 blk_dump_rq_flags(req
, "request botched");
2547 req
->__data_len
= blk_rq_cur_bytes(req
);
2550 /* recalculate the number of segments */
2551 blk_recalc_rq_segments(req
);
2555 EXPORT_SYMBOL_GPL(blk_update_request
);
2557 static bool blk_update_bidi_request(struct request
*rq
, int error
,
2558 unsigned int nr_bytes
,
2559 unsigned int bidi_bytes
)
2561 if (blk_update_request(rq
, error
, nr_bytes
))
2564 /* Bidi request must be completed as a whole */
2565 if (unlikely(blk_bidi_rq(rq
)) &&
2566 blk_update_request(rq
->next_rq
, error
, bidi_bytes
))
2569 if (blk_queue_add_random(rq
->q
))
2570 add_disk_randomness(rq
->rq_disk
);
2576 * blk_unprep_request - unprepare a request
2579 * This function makes a request ready for complete resubmission (or
2580 * completion). It happens only after all error handling is complete,
2581 * so represents the appropriate moment to deallocate any resources
2582 * that were allocated to the request in the prep_rq_fn. The queue
2583 * lock is held when calling this.
2585 void blk_unprep_request(struct request
*req
)
2587 struct request_queue
*q
= req
->q
;
2589 req
->cmd_flags
&= ~REQ_DONTPREP
;
2590 if (q
->unprep_rq_fn
)
2591 q
->unprep_rq_fn(q
, req
);
2593 EXPORT_SYMBOL_GPL(blk_unprep_request
);
2596 * queue lock must be held
2598 void blk_finish_request(struct request
*req
, int error
)
2600 if (req
->cmd_flags
& REQ_QUEUED
)
2601 blk_queue_end_tag(req
->q
, req
);
2603 BUG_ON(blk_queued_rq(req
));
2605 if (unlikely(laptop_mode
) && req
->cmd_type
== REQ_TYPE_FS
)
2606 laptop_io_completion(&req
->q
->backing_dev_info
);
2608 blk_delete_timer(req
);
2610 if (req
->cmd_flags
& REQ_DONTPREP
)
2611 blk_unprep_request(req
);
2613 blk_account_io_done(req
);
2616 req
->end_io(req
, error
);
2618 if (blk_bidi_rq(req
))
2619 __blk_put_request(req
->next_rq
->q
, req
->next_rq
);
2621 __blk_put_request(req
->q
, req
);
2624 EXPORT_SYMBOL(blk_finish_request
);
2627 * blk_end_bidi_request - Complete a bidi request
2628 * @rq: the request to complete
2629 * @error: %0 for success, < %0 for error
2630 * @nr_bytes: number of bytes to complete @rq
2631 * @bidi_bytes: number of bytes to complete @rq->next_rq
2634 * Ends I/O on a number of bytes attached to @rq and @rq->next_rq.
2635 * Drivers that supports bidi can safely call this member for any
2636 * type of request, bidi or uni. In the later case @bidi_bytes is
2640 * %false - we are done with this request
2641 * %true - still buffers pending for this request
2643 static bool blk_end_bidi_request(struct request
*rq
, int error
,
2644 unsigned int nr_bytes
, unsigned int bidi_bytes
)
2646 struct request_queue
*q
= rq
->q
;
2647 unsigned long flags
;
2649 if (blk_update_bidi_request(rq
, error
, nr_bytes
, bidi_bytes
))
2652 spin_lock_irqsave(q
->queue_lock
, flags
);
2653 blk_finish_request(rq
, error
);
2654 spin_unlock_irqrestore(q
->queue_lock
, flags
);
2660 * __blk_end_bidi_request - Complete a bidi request with queue lock held
2661 * @rq: the request to complete
2662 * @error: %0 for success, < %0 for error
2663 * @nr_bytes: number of bytes to complete @rq
2664 * @bidi_bytes: number of bytes to complete @rq->next_rq
2667 * Identical to blk_end_bidi_request() except that queue lock is
2668 * assumed to be locked on entry and remains so on return.
2671 * %false - we are done with this request
2672 * %true - still buffers pending for this request
2674 bool __blk_end_bidi_request(struct request
*rq
, int error
,
2675 unsigned int nr_bytes
, unsigned int bidi_bytes
)
2677 if (blk_update_bidi_request(rq
, error
, nr_bytes
, bidi_bytes
))
2680 blk_finish_request(rq
, error
);
2686 * blk_end_request - Helper function for drivers to complete the request.
2687 * @rq: the request being processed
2688 * @error: %0 for success, < %0 for error
2689 * @nr_bytes: number of bytes to complete
2692 * Ends I/O on a number of bytes attached to @rq.
2693 * If @rq has leftover, sets it up for the next range of segments.
2696 * %false - we are done with this request
2697 * %true - still buffers pending for this request
2699 bool blk_end_request(struct request
*rq
, int error
, unsigned int nr_bytes
)
2701 return blk_end_bidi_request(rq
, error
, nr_bytes
, 0);
2703 EXPORT_SYMBOL(blk_end_request
);
2706 * blk_end_request_all - Helper function for drives to finish the request.
2707 * @rq: the request to finish
2708 * @error: %0 for success, < %0 for error
2711 * Completely finish @rq.
2713 void blk_end_request_all(struct request
*rq
, int error
)
2716 unsigned int bidi_bytes
= 0;
2718 if (unlikely(blk_bidi_rq(rq
)))
2719 bidi_bytes
= blk_rq_bytes(rq
->next_rq
);
2721 pending
= blk_end_bidi_request(rq
, error
, blk_rq_bytes(rq
), bidi_bytes
);
2724 EXPORT_SYMBOL(blk_end_request_all
);
2727 * blk_end_request_cur - Helper function to finish the current request chunk.
2728 * @rq: the request to finish the current chunk for
2729 * @error: %0 for success, < %0 for error
2732 * Complete the current consecutively mapped chunk from @rq.
2735 * %false - we are done with this request
2736 * %true - still buffers pending for this request
2738 bool blk_end_request_cur(struct request
*rq
, int error
)
2740 return blk_end_request(rq
, error
, blk_rq_cur_bytes(rq
));
2742 EXPORT_SYMBOL(blk_end_request_cur
);
2745 * blk_end_request_err - Finish a request till the next failure boundary.
2746 * @rq: the request to finish till the next failure boundary for
2747 * @error: must be negative errno
2750 * Complete @rq till the next failure boundary.
2753 * %false - we are done with this request
2754 * %true - still buffers pending for this request
2756 bool blk_end_request_err(struct request
*rq
, int error
)
2758 WARN_ON(error
>= 0);
2759 return blk_end_request(rq
, error
, blk_rq_err_bytes(rq
));
2761 EXPORT_SYMBOL_GPL(blk_end_request_err
);
2764 * __blk_end_request - Helper function for drivers to complete the request.
2765 * @rq: the request being processed
2766 * @error: %0 for success, < %0 for error
2767 * @nr_bytes: number of bytes to complete
2770 * Must be called with queue lock held unlike blk_end_request().
2773 * %false - we are done with this request
2774 * %true - still buffers pending for this request
2776 bool __blk_end_request(struct request
*rq
, int error
, unsigned int nr_bytes
)
2778 return __blk_end_bidi_request(rq
, error
, nr_bytes
, 0);
2780 EXPORT_SYMBOL(__blk_end_request
);
2783 * __blk_end_request_all - Helper function for drives to finish the request.
2784 * @rq: the request to finish
2785 * @error: %0 for success, < %0 for error
2788 * Completely finish @rq. Must be called with queue lock held.
2790 void __blk_end_request_all(struct request
*rq
, int error
)
2793 unsigned int bidi_bytes
= 0;
2795 if (unlikely(blk_bidi_rq(rq
)))
2796 bidi_bytes
= blk_rq_bytes(rq
->next_rq
);
2798 pending
= __blk_end_bidi_request(rq
, error
, blk_rq_bytes(rq
), bidi_bytes
);
2801 EXPORT_SYMBOL(__blk_end_request_all
);
2804 * __blk_end_request_cur - Helper function to finish the current request chunk.
2805 * @rq: the request to finish the current chunk for
2806 * @error: %0 for success, < %0 for error
2809 * Complete the current consecutively mapped chunk from @rq. Must
2810 * be called with queue lock held.
2813 * %false - we are done with this request
2814 * %true - still buffers pending for this request
2816 bool __blk_end_request_cur(struct request
*rq
, int error
)
2818 return __blk_end_request(rq
, error
, blk_rq_cur_bytes(rq
));
2820 EXPORT_SYMBOL(__blk_end_request_cur
);
2823 * __blk_end_request_err - Finish a request till the next failure boundary.
2824 * @rq: the request to finish till the next failure boundary for
2825 * @error: must be negative errno
2828 * Complete @rq till the next failure boundary. Must be called
2829 * with queue lock held.
2832 * %false - we are done with this request
2833 * %true - still buffers pending for this request
2835 bool __blk_end_request_err(struct request
*rq
, int error
)
2837 WARN_ON(error
>= 0);
2838 return __blk_end_request(rq
, error
, blk_rq_err_bytes(rq
));
2840 EXPORT_SYMBOL_GPL(__blk_end_request_err
);
2842 void blk_rq_bio_prep(struct request_queue
*q
, struct request
*rq
,
2845 /* Bit 0 (R/W) is identical in rq->cmd_flags and bio->bi_rw */
2846 rq
->cmd_flags
|= bio
->bi_rw
& REQ_WRITE
;
2848 if (bio_has_data(bio
))
2849 rq
->nr_phys_segments
= bio_phys_segments(q
, bio
);
2851 rq
->__data_len
= bio
->bi_iter
.bi_size
;
2852 rq
->bio
= rq
->biotail
= bio
;
2855 rq
->rq_disk
= bio
->bi_bdev
->bd_disk
;
2858 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
2860 * rq_flush_dcache_pages - Helper function to flush all pages in a request
2861 * @rq: the request to be flushed
2864 * Flush all pages in @rq.
2866 void rq_flush_dcache_pages(struct request
*rq
)
2868 struct req_iterator iter
;
2869 struct bio_vec bvec
;
2871 rq_for_each_segment(bvec
, rq
, iter
)
2872 flush_dcache_page(bvec
.bv_page
);
2874 EXPORT_SYMBOL_GPL(rq_flush_dcache_pages
);
2878 * blk_lld_busy - Check if underlying low-level drivers of a device are busy
2879 * @q : the queue of the device being checked
2882 * Check if underlying low-level drivers of a device are busy.
2883 * If the drivers want to export their busy state, they must set own
2884 * exporting function using blk_queue_lld_busy() first.
2886 * Basically, this function is used only by request stacking drivers
2887 * to stop dispatching requests to underlying devices when underlying
2888 * devices are busy. This behavior helps more I/O merging on the queue
2889 * of the request stacking driver and prevents I/O throughput regression
2890 * on burst I/O load.
2893 * 0 - Not busy (The request stacking driver should dispatch request)
2894 * 1 - Busy (The request stacking driver should stop dispatching request)
2896 int blk_lld_busy(struct request_queue
*q
)
2899 return q
->lld_busy_fn(q
);
2903 EXPORT_SYMBOL_GPL(blk_lld_busy
);
2906 * blk_rq_unprep_clone - Helper function to free all bios in a cloned request
2907 * @rq: the clone request to be cleaned up
2910 * Free all bios in @rq for a cloned request.
2912 void blk_rq_unprep_clone(struct request
*rq
)
2916 while ((bio
= rq
->bio
) != NULL
) {
2917 rq
->bio
= bio
->bi_next
;
2922 EXPORT_SYMBOL_GPL(blk_rq_unprep_clone
);
2925 * Copy attributes of the original request to the clone request.
2926 * The actual data parts (e.g. ->cmd, ->sense) are not copied.
2928 static void __blk_rq_prep_clone(struct request
*dst
, struct request
*src
)
2930 dst
->cpu
= src
->cpu
;
2931 dst
->cmd_flags
|= (src
->cmd_flags
& REQ_CLONE_MASK
) | REQ_NOMERGE
;
2932 dst
->cmd_type
= src
->cmd_type
;
2933 dst
->__sector
= blk_rq_pos(src
);
2934 dst
->__data_len
= blk_rq_bytes(src
);
2935 dst
->nr_phys_segments
= src
->nr_phys_segments
;
2936 dst
->ioprio
= src
->ioprio
;
2937 dst
->extra_len
= src
->extra_len
;
2941 * blk_rq_prep_clone - Helper function to setup clone request
2942 * @rq: the request to be setup
2943 * @rq_src: original request to be cloned
2944 * @bs: bio_set that bios for clone are allocated from
2945 * @gfp_mask: memory allocation mask for bio
2946 * @bio_ctr: setup function to be called for each clone bio.
2947 * Returns %0 for success, non %0 for failure.
2948 * @data: private data to be passed to @bio_ctr
2951 * Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq.
2952 * The actual data parts of @rq_src (e.g. ->cmd, ->sense)
2953 * are not copied, and copying such parts is the caller's responsibility.
2954 * Also, pages which the original bios are pointing to are not copied
2955 * and the cloned bios just point same pages.
2956 * So cloned bios must be completed before original bios, which means
2957 * the caller must complete @rq before @rq_src.
2959 int blk_rq_prep_clone(struct request
*rq
, struct request
*rq_src
,
2960 struct bio_set
*bs
, gfp_t gfp_mask
,
2961 int (*bio_ctr
)(struct bio
*, struct bio
*, void *),
2964 struct bio
*bio
, *bio_src
;
2969 __rq_for_each_bio(bio_src
, rq_src
) {
2970 bio
= bio_clone_fast(bio_src
, gfp_mask
, bs
);
2974 if (bio_ctr
&& bio_ctr(bio
, bio_src
, data
))
2978 rq
->biotail
->bi_next
= bio
;
2981 rq
->bio
= rq
->biotail
= bio
;
2984 __blk_rq_prep_clone(rq
, rq_src
);
2991 blk_rq_unprep_clone(rq
);
2995 EXPORT_SYMBOL_GPL(blk_rq_prep_clone
);
2997 int kblockd_schedule_work(struct work_struct
*work
)
2999 return queue_work(kblockd_workqueue
, work
);
3001 EXPORT_SYMBOL(kblockd_schedule_work
);
3003 int kblockd_schedule_delayed_work(struct delayed_work
*dwork
,
3004 unsigned long delay
)
3006 return queue_delayed_work(kblockd_workqueue
, dwork
, delay
);
3008 EXPORT_SYMBOL(kblockd_schedule_delayed_work
);
3010 int kblockd_schedule_delayed_work_on(int cpu
, struct delayed_work
*dwork
,
3011 unsigned long delay
)
3013 return queue_delayed_work_on(cpu
, kblockd_workqueue
, dwork
, delay
);
3015 EXPORT_SYMBOL(kblockd_schedule_delayed_work_on
);
3018 * blk_start_plug - initialize blk_plug and track it inside the task_struct
3019 * @plug: The &struct blk_plug that needs to be initialized
3022 * Tracking blk_plug inside the task_struct will help with auto-flushing the
3023 * pending I/O should the task end up blocking between blk_start_plug() and
3024 * blk_finish_plug(). This is important from a performance perspective, but
3025 * also ensures that we don't deadlock. For instance, if the task is blocking
3026 * for a memory allocation, memory reclaim could end up wanting to free a
3027 * page belonging to that request that is currently residing in our private
3028 * plug. By flushing the pending I/O when the process goes to sleep, we avoid
3029 * this kind of deadlock.
3031 void blk_start_plug(struct blk_plug
*plug
)
3033 struct task_struct
*tsk
= current
;
3035 INIT_LIST_HEAD(&plug
->list
);
3036 INIT_LIST_HEAD(&plug
->mq_list
);
3037 INIT_LIST_HEAD(&plug
->cb_list
);
3040 * If this is a nested plug, don't actually assign it. It will be
3041 * flushed on its own.
3045 * Store ordering should not be needed here, since a potential
3046 * preempt will imply a full memory barrier
3051 EXPORT_SYMBOL(blk_start_plug
);
3053 static int plug_rq_cmp(void *priv
, struct list_head
*a
, struct list_head
*b
)
3055 struct request
*rqa
= container_of(a
, struct request
, queuelist
);
3056 struct request
*rqb
= container_of(b
, struct request
, queuelist
);
3058 return !(rqa
->q
< rqb
->q
||
3059 (rqa
->q
== rqb
->q
&& blk_rq_pos(rqa
) < blk_rq_pos(rqb
)));
3063 * If 'from_schedule' is true, then postpone the dispatch of requests
3064 * until a safe kblockd context. We due this to avoid accidental big
3065 * additional stack usage in driver dispatch, in places where the originally
3066 * plugger did not intend it.
3068 static void queue_unplugged(struct request_queue
*q
, unsigned int depth
,
3070 __releases(q
->queue_lock
)
3072 trace_block_unplug(q
, depth
, !from_schedule
);
3075 blk_run_queue_async(q
);
3078 spin_unlock(q
->queue_lock
);
3081 static void flush_plug_callbacks(struct blk_plug
*plug
, bool from_schedule
)
3083 LIST_HEAD(callbacks
);
3085 while (!list_empty(&plug
->cb_list
)) {
3086 list_splice_init(&plug
->cb_list
, &callbacks
);
3088 while (!list_empty(&callbacks
)) {
3089 struct blk_plug_cb
*cb
= list_first_entry(&callbacks
,
3092 list_del(&cb
->list
);
3093 cb
->callback(cb
, from_schedule
);
3098 struct blk_plug_cb
*blk_check_plugged(blk_plug_cb_fn unplug
, void *data
,
3101 struct blk_plug
*plug
= current
->plug
;
3102 struct blk_plug_cb
*cb
;
3107 list_for_each_entry(cb
, &plug
->cb_list
, list
)
3108 if (cb
->callback
== unplug
&& cb
->data
== data
)
3111 /* Not currently on the callback list */
3112 BUG_ON(size
< sizeof(*cb
));
3113 cb
= kzalloc(size
, GFP_ATOMIC
);
3116 cb
->callback
= unplug
;
3117 list_add(&cb
->list
, &plug
->cb_list
);
3121 EXPORT_SYMBOL(blk_check_plugged
);
3123 void blk_flush_plug_list(struct blk_plug
*plug
, bool from_schedule
)
3125 struct request_queue
*q
;
3126 unsigned long flags
;
3131 flush_plug_callbacks(plug
, from_schedule
);
3133 if (!list_empty(&plug
->mq_list
))
3134 blk_mq_flush_plug_list(plug
, from_schedule
);
3136 if (list_empty(&plug
->list
))
3139 list_splice_init(&plug
->list
, &list
);
3141 list_sort(NULL
, &list
, plug_rq_cmp
);
3147 * Save and disable interrupts here, to avoid doing it for every
3148 * queue lock we have to take.
3150 local_irq_save(flags
);
3151 while (!list_empty(&list
)) {
3152 rq
= list_entry_rq(list
.next
);
3153 list_del_init(&rq
->queuelist
);
3157 * This drops the queue lock
3160 queue_unplugged(q
, depth
, from_schedule
);
3163 spin_lock(q
->queue_lock
);
3167 * Short-circuit if @q is dead
3169 if (unlikely(blk_queue_dying(q
))) {
3170 __blk_end_request_all(rq
, -ENODEV
);
3175 * rq is already accounted, so use raw insert
3177 if (rq
->cmd_flags
& (REQ_FLUSH
| REQ_FUA
))
3178 __elv_add_request(q
, rq
, ELEVATOR_INSERT_FLUSH
);
3180 __elv_add_request(q
, rq
, ELEVATOR_INSERT_SORT_MERGE
);
3186 * This drops the queue lock
3189 queue_unplugged(q
, depth
, from_schedule
);
3191 local_irq_restore(flags
);
3194 void blk_finish_plug(struct blk_plug
*plug
)
3196 blk_flush_plug_list(plug
, false);
3198 if (plug
== current
->plug
)
3199 current
->plug
= NULL
;
3201 EXPORT_SYMBOL(blk_finish_plug
);
3205 * blk_pm_runtime_init - Block layer runtime PM initialization routine
3206 * @q: the queue of the device
3207 * @dev: the device the queue belongs to
3210 * Initialize runtime-PM-related fields for @q and start auto suspend for
3211 * @dev. Drivers that want to take advantage of request-based runtime PM
3212 * should call this function after @dev has been initialized, and its
3213 * request queue @q has been allocated, and runtime PM for it can not happen
3214 * yet(either due to disabled/forbidden or its usage_count > 0). In most
3215 * cases, driver should call this function before any I/O has taken place.
3217 * This function takes care of setting up using auto suspend for the device,
3218 * the autosuspend delay is set to -1 to make runtime suspend impossible
3219 * until an updated value is either set by user or by driver. Drivers do
3220 * not need to touch other autosuspend settings.
3222 * The block layer runtime PM is request based, so only works for drivers
3223 * that use request as their IO unit instead of those directly use bio's.
3225 void blk_pm_runtime_init(struct request_queue
*q
, struct device
*dev
)
3228 q
->rpm_status
= RPM_ACTIVE
;
3229 pm_runtime_set_autosuspend_delay(q
->dev
, -1);
3230 pm_runtime_use_autosuspend(q
->dev
);
3232 EXPORT_SYMBOL(blk_pm_runtime_init
);
3235 * blk_pre_runtime_suspend - Pre runtime suspend check
3236 * @q: the queue of the device
3239 * This function will check if runtime suspend is allowed for the device
3240 * by examining if there are any requests pending in the queue. If there
3241 * are requests pending, the device can not be runtime suspended; otherwise,
3242 * the queue's status will be updated to SUSPENDING and the driver can
3243 * proceed to suspend the device.
3245 * For the not allowed case, we mark last busy for the device so that
3246 * runtime PM core will try to autosuspend it some time later.
3248 * This function should be called near the start of the device's
3249 * runtime_suspend callback.
3252 * 0 - OK to runtime suspend the device
3253 * -EBUSY - Device should not be runtime suspended
3255 int blk_pre_runtime_suspend(struct request_queue
*q
)
3259 spin_lock_irq(q
->queue_lock
);
3260 if (q
->nr_pending
) {
3262 pm_runtime_mark_last_busy(q
->dev
);
3264 q
->rpm_status
= RPM_SUSPENDING
;
3266 spin_unlock_irq(q
->queue_lock
);
3269 EXPORT_SYMBOL(blk_pre_runtime_suspend
);
3272 * blk_post_runtime_suspend - Post runtime suspend processing
3273 * @q: the queue of the device
3274 * @err: return value of the device's runtime_suspend function
3277 * Update the queue's runtime status according to the return value of the
3278 * device's runtime suspend function and mark last busy for the device so
3279 * that PM core will try to auto suspend the device at a later time.
3281 * This function should be called near the end of the device's
3282 * runtime_suspend callback.
3284 void blk_post_runtime_suspend(struct request_queue
*q
, int err
)
3286 spin_lock_irq(q
->queue_lock
);
3288 q
->rpm_status
= RPM_SUSPENDED
;
3290 q
->rpm_status
= RPM_ACTIVE
;
3291 pm_runtime_mark_last_busy(q
->dev
);
3293 spin_unlock_irq(q
->queue_lock
);
3295 EXPORT_SYMBOL(blk_post_runtime_suspend
);
3298 * blk_pre_runtime_resume - Pre runtime resume processing
3299 * @q: the queue of the device
3302 * Update the queue's runtime status to RESUMING in preparation for the
3303 * runtime resume of the device.
3305 * This function should be called near the start of the device's
3306 * runtime_resume callback.
3308 void blk_pre_runtime_resume(struct request_queue
*q
)
3310 spin_lock_irq(q
->queue_lock
);
3311 q
->rpm_status
= RPM_RESUMING
;
3312 spin_unlock_irq(q
->queue_lock
);
3314 EXPORT_SYMBOL(blk_pre_runtime_resume
);
3317 * blk_post_runtime_resume - Post runtime resume processing
3318 * @q: the queue of the device
3319 * @err: return value of the device's runtime_resume function
3322 * Update the queue's runtime status according to the return value of the
3323 * device's runtime_resume function. If it is successfully resumed, process
3324 * the requests that are queued into the device's queue when it is resuming
3325 * and then mark last busy and initiate autosuspend for it.
3327 * This function should be called near the end of the device's
3328 * runtime_resume callback.
3330 void blk_post_runtime_resume(struct request_queue
*q
, int err
)
3332 spin_lock_irq(q
->queue_lock
);
3334 q
->rpm_status
= RPM_ACTIVE
;
3336 pm_runtime_mark_last_busy(q
->dev
);
3337 pm_request_autosuspend(q
->dev
);
3339 q
->rpm_status
= RPM_SUSPENDED
;
3341 spin_unlock_irq(q
->queue_lock
);
3343 EXPORT_SYMBOL(blk_post_runtime_resume
);
3346 int __init
blk_dev_init(void)
3348 BUILD_BUG_ON(__REQ_NR_BITS
> 8 *
3349 sizeof(((struct request
*)0)->cmd_flags
));
3351 /* used for unplugging and affects IO latency/throughput - HIGHPRI */
3352 kblockd_workqueue
= alloc_workqueue("kblockd",
3353 WQ_MEM_RECLAIM
| WQ_HIGHPRI
, 0);
3354 if (!kblockd_workqueue
)
3355 panic("Failed to create kblockd\n");
3357 request_cachep
= kmem_cache_create("blkdev_requests",
3358 sizeof(struct request
), 0, SLAB_PANIC
, NULL
);
3360 blk_requestq_cachep
= kmem_cache_create("blkdev_queue",
3361 sizeof(struct request_queue
), 0, SLAB_PANIC
, NULL
);