1 #ifndef _LINUX_BLKDEV_H
2 #define _LINUX_BLKDEV_H
4 #include <linux/sched.h>
8 #include <linux/major.h>
9 #include <linux/genhd.h>
10 #include <linux/list.h>
11 #include <linux/timer.h>
12 #include <linux/workqueue.h>
13 #include <linux/pagemap.h>
14 #include <linux/backing-dev.h>
15 #include <linux/wait.h>
16 #include <linux/mempool.h>
17 #include <linux/bio.h>
18 #include <linux/stringify.h>
19 #include <linux/gfp.h>
20 #include <linux/bsg.h>
21 #include <linux/smp.h>
22 #include <linux/rcupdate.h>
24 #include <asm/scatterlist.h>
27 struct scsi_ioctl_command;
30 struct elevator_queue;
31 struct request_pm_state;
38 #define BLKDEV_MIN_RQ 4
39 #define BLKDEV_MAX_RQ 128 /* Default maximum */
42 * Maximum number of blkcg policies allowed to be registered concurrently.
43 * Defined here to simplify include dependency.
45 #define BLKCG_MAX_POLS 2
48 typedef void (rq_end_io_fn)(struct request *, int);
50 #define BLK_RL_SYNCFULL (1U << 0)
51 #define BLK_RL_ASYNCFULL (1U << 1)
54 struct request_queue *q; /* the queue this rl belongs to */
55 #ifdef CONFIG_BLK_CGROUP
56 struct blkcg_gq *blkg; /* blkg this request pool belongs to */
59 * count[], starved[], and wait[] are indexed by
60 * BLK_RW_SYNC/BLK_RW_ASYNC
65 wait_queue_head_t wait[2];
70 * request command types
72 enum rq_cmd_type_bits {
73 REQ_TYPE_FS = 1, /* fs request */
74 REQ_TYPE_BLOCK_PC, /* scsi command */
75 REQ_TYPE_SENSE, /* sense request */
76 REQ_TYPE_PM_SUSPEND, /* suspend request */
77 REQ_TYPE_PM_RESUME, /* resume request */
78 REQ_TYPE_PM_SHUTDOWN, /* shutdown request */
79 REQ_TYPE_SPECIAL, /* driver defined type */
81 * for ATA/ATAPI devices. this really doesn't belong here, ide should
82 * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver
83 * private REQ_LB opcodes to differentiate what type of request this is
85 REQ_TYPE_ATA_TASKFILE,
89 #define BLK_MAX_CDB 16
92 * try to put the fields that are referenced together in the same cacheline.
93 * if you modify this structure, be sure to check block/blk-core.c:blk_rq_init()
97 struct list_head queuelist;
98 struct call_single_data csd;
100 struct request_queue *q;
103 enum rq_cmd_type_bits cmd_type;
104 unsigned long atomic_flags;
108 /* the following two fields are internal, NEVER access directly */
109 unsigned int __data_len; /* total data len */
110 sector_t __sector; /* sector cursor */
115 struct hlist_node hash; /* merge hash */
117 * The rb_node is only used inside the io scheduler, requests
118 * are pruned when moved to the dispatch queue. So let the
119 * completion_data share space with the rb_node.
122 struct rb_node rb_node; /* sort/lookup */
123 void *completion_data;
127 * Three pointers are available for the IO schedulers, if they need
128 * more they have to dynamically allocate it. Flush requests are
129 * never put on the IO scheduler. So let the flush fields share
130 * space with the elevator data.
140 struct list_head list;
141 rq_end_io_fn *saved_end_io;
145 struct gendisk *rq_disk;
146 struct hd_struct *part;
147 unsigned long start_time;
148 #ifdef CONFIG_BLK_CGROUP
149 struct request_list *rl; /* rl this rq is alloced from */
150 unsigned long long start_time_ns;
151 unsigned long long io_start_time_ns; /* when passed to hardware */
153 /* Number of scatter-gather DMA addr+len pairs after
154 * physical address coalescing is performed.
156 unsigned short nr_phys_segments;
157 #if defined(CONFIG_BLK_DEV_INTEGRITY)
158 unsigned short nr_integrity_segments;
161 unsigned short ioprio;
163 void *special; /* opaque pointer available for LLD use */
164 char *buffer; /* kaddr of the current segment if available */
170 * when request is used as a packet command carrier
172 unsigned char __cmd[BLK_MAX_CDB];
174 unsigned short cmd_len;
176 unsigned int extra_len; /* length of alignment and padding */
177 unsigned int sense_len;
178 unsigned int resid_len; /* residual count */
181 unsigned long deadline;
182 struct list_head timeout_list;
183 unsigned int timeout;
187 * completion callback.
189 rq_end_io_fn *end_io;
193 struct request *next_rq;
196 static inline unsigned short req_get_ioprio(struct request *req)
202 * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
203 * requests. Some step values could eventually be made generic.
205 struct request_pm_state
207 /* PM state machine step value, currently driver specific */
209 /* requested PM state value (S1, S2, S3, S4, ...) */
211 void* data; /* for driver use */
214 #include <linux/elevator.h>
216 typedef void (request_fn_proc) (struct request_queue *q);
217 typedef void (make_request_fn) (struct request_queue *q, struct bio *bio);
218 typedef int (prep_rq_fn) (struct request_queue *, struct request *);
219 typedef void (unprep_rq_fn) (struct request_queue *, struct request *);
222 struct bvec_merge_data {
223 struct block_device *bi_bdev;
228 typedef int (merge_bvec_fn) (struct request_queue *, struct bvec_merge_data *,
230 typedef void (softirq_done_fn)(struct request *);
231 typedef int (dma_drain_needed_fn)(struct request *);
232 typedef int (lld_busy_fn) (struct request_queue *q);
233 typedef int (bsg_job_fn) (struct bsg_job *);
235 enum blk_eh_timer_return {
241 typedef enum blk_eh_timer_return (rq_timed_out_fn)(struct request *);
243 enum blk_queue_state {
248 struct blk_queue_tag {
249 struct request **tag_index; /* map of busy tags */
250 unsigned long *tag_map; /* bit map of free/busy tags */
251 int busy; /* current depth */
252 int max_depth; /* what we will send to device */
253 int real_max_depth; /* what the array can hold */
254 atomic_t refcnt; /* map can be shared */
257 #define BLK_SCSI_MAX_CMDS (256)
258 #define BLK_SCSI_CMD_PER_LONG (BLK_SCSI_MAX_CMDS / (sizeof(long) * 8))
260 struct queue_limits {
261 unsigned long bounce_pfn;
262 unsigned long seg_boundary_mask;
264 unsigned int max_hw_sectors;
265 unsigned int max_sectors;
266 unsigned int max_segment_size;
267 unsigned int physical_block_size;
268 unsigned int alignment_offset;
271 unsigned int max_discard_sectors;
272 unsigned int max_write_same_sectors;
273 unsigned int discard_granularity;
274 unsigned int discard_alignment;
276 unsigned short logical_block_size;
277 unsigned short max_segments;
278 unsigned short max_integrity_segments;
280 unsigned char misaligned;
281 unsigned char discard_misaligned;
282 unsigned char cluster;
283 unsigned char discard_zeroes_data;
286 struct request_queue {
288 * Together with queue_head for cacheline sharing
290 struct list_head queue_head;
291 struct request *last_merge;
292 struct elevator_queue *elevator;
293 int nr_rqs[2]; /* # allocated [a]sync rqs */
294 int nr_rqs_elvpriv; /* # allocated rqs w/ elvpriv */
297 * If blkcg is not used, @q->root_rl serves all requests. If blkcg
298 * is used, root blkg allocates from @q->root_rl and all other
299 * blkgs from their own blkg->rl. Which one to use should be
300 * determined using bio_request_list().
302 struct request_list root_rl;
304 request_fn_proc *request_fn;
305 make_request_fn *make_request_fn;
306 prep_rq_fn *prep_rq_fn;
307 unprep_rq_fn *unprep_rq_fn;
308 merge_bvec_fn *merge_bvec_fn;
309 softirq_done_fn *softirq_done_fn;
310 rq_timed_out_fn *rq_timed_out_fn;
311 dma_drain_needed_fn *dma_drain_needed;
312 lld_busy_fn *lld_busy_fn;
315 * Dispatch queue sorting
318 struct request *boundary_rq;
321 * Delayed queue handling
323 struct delayed_work delay_work;
325 struct backing_dev_info backing_dev_info;
328 * The queue owner gets to use this for whatever they like.
329 * ll_rw_blk doesn't touch it.
334 * various queue flags, see QUEUE_* below
336 unsigned long queue_flags;
339 * ida allocated id for this queue. Used to index queues from
345 * queue needs bounce pages for pages above this limit
350 * protects queue structures from reentrancy. ->__queue_lock should
351 * _never_ be used directly, it is queue private. always use
354 spinlock_t __queue_lock;
355 spinlock_t *queue_lock;
362 #ifdef CONFIG_PM_RUNTIME
365 unsigned int nr_pending;
371 unsigned long nr_requests; /* Max # of requests */
372 unsigned int nr_congestion_on;
373 unsigned int nr_congestion_off;
374 unsigned int nr_batching;
376 unsigned int dma_drain_size;
377 void *dma_drain_buffer;
378 unsigned int dma_pad_mask;
379 unsigned int dma_alignment;
381 struct blk_queue_tag *queue_tags;
382 struct list_head tag_busy_list;
384 unsigned int nr_sorted;
385 unsigned int in_flight[2];
387 * Number of active block driver functions for which blk_drain_queue()
388 * must wait. Must be incremented around functions that unlock the
389 * queue_lock internally, e.g. scsi_request_fn().
391 unsigned int request_fn_active;
393 unsigned int rq_timeout;
394 struct timer_list timeout;
395 struct list_head timeout_list;
397 struct list_head icq_list;
398 #ifdef CONFIG_BLK_CGROUP
399 DECLARE_BITMAP (blkcg_pols, BLKCG_MAX_POLS);
400 struct blkcg_gq *root_blkg;
401 struct list_head blkg_list;
404 struct queue_limits limits;
409 unsigned int sg_timeout;
410 unsigned int sg_reserved_size;
412 #ifdef CONFIG_BLK_DEV_IO_TRACE
413 struct blk_trace *blk_trace;
416 * for flush operations
418 unsigned int flush_flags;
419 unsigned int flush_not_queueable:1;
420 unsigned int flush_queue_delayed:1;
421 unsigned int flush_pending_idx:1;
422 unsigned int flush_running_idx:1;
423 unsigned long flush_pending_since;
424 struct list_head flush_queue[2];
425 struct list_head flush_data_in_flight;
426 struct request flush_rq;
428 struct mutex sysfs_lock;
432 #if defined(CONFIG_BLK_DEV_BSG)
433 bsg_job_fn *bsg_job_fn;
435 struct bsg_class_device bsg_dev;
438 #ifdef CONFIG_BLK_CGROUP
439 struct list_head all_q_node;
441 #ifdef CONFIG_BLK_DEV_THROTTLING
443 struct throtl_data *td;
445 struct rcu_head rcu_head;
448 #define QUEUE_FLAG_QUEUED 1 /* uses generic tag queueing */
449 #define QUEUE_FLAG_STOPPED 2 /* queue is stopped */
450 #define QUEUE_FLAG_SYNCFULL 3 /* read queue has been filled */
451 #define QUEUE_FLAG_ASYNCFULL 4 /* write queue has been filled */
452 #define QUEUE_FLAG_DYING 5 /* queue being torn down */
453 #define QUEUE_FLAG_BYPASS 6 /* act as dumb FIFO queue */
454 #define QUEUE_FLAG_BIDI 7 /* queue supports bidi requests */
455 #define QUEUE_FLAG_NOMERGES 8 /* disable merge attempts */
456 #define QUEUE_FLAG_SAME_COMP 9 /* complete on same CPU-group */
457 #define QUEUE_FLAG_FAIL_IO 10 /* fake timeout */
458 #define QUEUE_FLAG_STACKABLE 11 /* supports request stacking */
459 #define QUEUE_FLAG_NONROT 12 /* non-rotational device (SSD) */
460 #define QUEUE_FLAG_VIRT QUEUE_FLAG_NONROT /* paravirt device */
461 #define QUEUE_FLAG_IO_STAT 13 /* do IO stats */
462 #define QUEUE_FLAG_DISCARD 14 /* supports DISCARD */
463 #define QUEUE_FLAG_NOXMERGES 15 /* No extended merges */
464 #define QUEUE_FLAG_ADD_RANDOM 16 /* Contributes to random pool */
465 #define QUEUE_FLAG_SECDISCARD 17 /* supports SECDISCARD */
466 #define QUEUE_FLAG_SAME_FORCE 18 /* force complete on same CPU */
467 #define QUEUE_FLAG_DEAD 19 /* queue tear-down finished */
469 #define QUEUE_FLAG_DEFAULT ((1 << QUEUE_FLAG_IO_STAT) | \
470 (1 << QUEUE_FLAG_STACKABLE) | \
471 (1 << QUEUE_FLAG_SAME_COMP) | \
472 (1 << QUEUE_FLAG_ADD_RANDOM))
474 static inline void queue_lockdep_assert_held(struct request_queue *q)
477 lockdep_assert_held(q->queue_lock);
480 static inline void queue_flag_set_unlocked(unsigned int flag,
481 struct request_queue *q)
483 __set_bit(flag, &q->queue_flags);
486 static inline int queue_flag_test_and_clear(unsigned int flag,
487 struct request_queue *q)
489 queue_lockdep_assert_held(q);
491 if (test_bit(flag, &q->queue_flags)) {
492 __clear_bit(flag, &q->queue_flags);
499 static inline int queue_flag_test_and_set(unsigned int flag,
500 struct request_queue *q)
502 queue_lockdep_assert_held(q);
504 if (!test_bit(flag, &q->queue_flags)) {
505 __set_bit(flag, &q->queue_flags);
512 static inline void queue_flag_set(unsigned int flag, struct request_queue *q)
514 queue_lockdep_assert_held(q);
515 __set_bit(flag, &q->queue_flags);
518 static inline void queue_flag_clear_unlocked(unsigned int flag,
519 struct request_queue *q)
521 __clear_bit(flag, &q->queue_flags);
524 static inline int queue_in_flight(struct request_queue *q)
526 return q->in_flight[0] + q->in_flight[1];
529 static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
531 queue_lockdep_assert_held(q);
532 __clear_bit(flag, &q->queue_flags);
535 #define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
536 #define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
537 #define blk_queue_dying(q) test_bit(QUEUE_FLAG_DYING, &(q)->queue_flags)
538 #define blk_queue_dead(q) test_bit(QUEUE_FLAG_DEAD, &(q)->queue_flags)
539 #define blk_queue_bypass(q) test_bit(QUEUE_FLAG_BYPASS, &(q)->queue_flags)
540 #define blk_queue_nomerges(q) test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
541 #define blk_queue_noxmerges(q) \
542 test_bit(QUEUE_FLAG_NOXMERGES, &(q)->queue_flags)
543 #define blk_queue_nonrot(q) test_bit(QUEUE_FLAG_NONROT, &(q)->queue_flags)
544 #define blk_queue_io_stat(q) test_bit(QUEUE_FLAG_IO_STAT, &(q)->queue_flags)
545 #define blk_queue_add_random(q) test_bit(QUEUE_FLAG_ADD_RANDOM, &(q)->queue_flags)
546 #define blk_queue_stackable(q) \
547 test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags)
548 #define blk_queue_discard(q) test_bit(QUEUE_FLAG_DISCARD, &(q)->queue_flags)
549 #define blk_queue_secdiscard(q) (blk_queue_discard(q) && \
550 test_bit(QUEUE_FLAG_SECDISCARD, &(q)->queue_flags))
552 #define blk_noretry_request(rq) \
553 ((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \
554 REQ_FAILFAST_DRIVER))
556 #define blk_account_rq(rq) \
557 (((rq)->cmd_flags & REQ_STARTED) && \
558 ((rq)->cmd_type == REQ_TYPE_FS))
560 #define blk_pm_request(rq) \
561 ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND || \
562 (rq)->cmd_type == REQ_TYPE_PM_RESUME)
564 #define blk_rq_cpu_valid(rq) ((rq)->cpu != -1)
565 #define blk_bidi_rq(rq) ((rq)->next_rq != NULL)
566 /* rq->queuelist of dequeued request must be list_empty() */
567 #define blk_queued_rq(rq) (!list_empty(&(rq)->queuelist))
569 #define list_entry_rq(ptr) list_entry((ptr), struct request, queuelist)
571 #define rq_data_dir(rq) (((rq)->cmd_flags & 1) != 0)
573 static inline unsigned int blk_queue_cluster(struct request_queue *q)
575 return q->limits.cluster;
579 * We regard a request as sync, if either a read or a sync write
581 static inline bool rw_is_sync(unsigned int rw_flags)
583 return !(rw_flags & REQ_WRITE) || (rw_flags & REQ_SYNC);
586 static inline bool rq_is_sync(struct request *rq)
588 return rw_is_sync(rq->cmd_flags);
591 static inline bool blk_rl_full(struct request_list *rl, bool sync)
593 unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
595 return rl->flags & flag;
598 static inline void blk_set_rl_full(struct request_list *rl, bool sync)
600 unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
605 static inline void blk_clear_rl_full(struct request_list *rl, bool sync)
607 unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
612 static inline bool rq_mergeable(struct request *rq)
614 if (rq->cmd_type != REQ_TYPE_FS)
617 if (rq->cmd_flags & REQ_NOMERGE_FLAGS)
623 static inline bool blk_check_merge_flags(unsigned int flags1,
626 if ((flags1 & REQ_DISCARD) != (flags2 & REQ_DISCARD))
629 if ((flags1 & REQ_SECURE) != (flags2 & REQ_SECURE))
632 if ((flags1 & REQ_WRITE_SAME) != (flags2 & REQ_WRITE_SAME))
638 static inline bool blk_write_same_mergeable(struct bio *a, struct bio *b)
640 if (bio_data(a) == bio_data(b))
647 * q->prep_rq_fn return values
649 #define BLKPREP_OK 0 /* serve it */
650 #define BLKPREP_KILL 1 /* fatal error, kill */
651 #define BLKPREP_DEFER 2 /* leave on queue */
653 extern unsigned long blk_max_low_pfn, blk_max_pfn;
656 * standard bounce addresses:
658 * BLK_BOUNCE_HIGH : bounce all highmem pages
659 * BLK_BOUNCE_ANY : don't bounce anything
660 * BLK_BOUNCE_ISA : bounce pages above ISA DMA boundary
663 #if BITS_PER_LONG == 32
664 #define BLK_BOUNCE_HIGH ((u64)blk_max_low_pfn << PAGE_SHIFT)
666 #define BLK_BOUNCE_HIGH -1ULL
668 #define BLK_BOUNCE_ANY (-1ULL)
669 #define BLK_BOUNCE_ISA (DMA_BIT_MASK(24))
672 * default timeout for SG_IO if none specified
674 #define BLK_DEFAULT_SG_TIMEOUT (60 * HZ)
675 #define BLK_MIN_SG_TIMEOUT (7 * HZ)
678 extern int init_emergency_isa_pool(void);
679 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
681 static inline int init_emergency_isa_pool(void)
685 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
688 #endif /* CONFIG_MMU */
694 unsigned long offset;
699 struct req_iterator {
704 /* This should not be used directly - use rq_for_each_segment */
705 #define for_each_bio(_bio) \
706 for (; _bio; _bio = _bio->bi_next)
707 #define __rq_for_each_bio(_bio, rq) \
709 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
711 #define rq_for_each_segment(bvl, _rq, _iter) \
712 __rq_for_each_bio(_iter.bio, _rq) \
713 bio_for_each_segment(bvl, _iter.bio, _iter.i)
715 #define rq_iter_last(rq, _iter) \
716 (_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)
718 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
719 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
721 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
722 extern void rq_flush_dcache_pages(struct request *rq);
724 static inline void rq_flush_dcache_pages(struct request *rq)
729 extern int blk_register_queue(struct gendisk *disk);
730 extern void blk_unregister_queue(struct gendisk *disk);
731 extern void generic_make_request(struct bio *bio);
732 extern void blk_rq_init(struct request_queue *q, struct request *rq);
733 extern void blk_put_request(struct request *);
734 extern void __blk_put_request(struct request_queue *, struct request *);
735 extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
736 extern struct request *blk_make_request(struct request_queue *, struct bio *,
738 extern void blk_requeue_request(struct request_queue *, struct request *);
739 extern void blk_add_request_payload(struct request *rq, struct page *page,
741 extern int blk_rq_check_limits(struct request_queue *q, struct request *rq);
742 extern int blk_lld_busy(struct request_queue *q);
743 extern int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
744 struct bio_set *bs, gfp_t gfp_mask,
745 int (*bio_ctr)(struct bio *, struct bio *, void *),
747 extern void blk_rq_unprep_clone(struct request *rq);
748 extern int blk_insert_cloned_request(struct request_queue *q,
750 extern void blk_delay_queue(struct request_queue *, unsigned long);
751 extern void blk_recount_segments(struct request_queue *, struct bio *);
752 extern int scsi_verify_blk_ioctl(struct block_device *, unsigned int);
753 extern int scsi_cmd_blk_ioctl(struct block_device *, fmode_t,
754 unsigned int, void __user *);
755 extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t,
756 unsigned int, void __user *);
757 extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t,
758 struct scsi_ioctl_command __user *);
760 extern void blk_queue_bio(struct request_queue *q, struct bio *bio);
763 * A queue has just exitted congestion. Note this in the global counter of
764 * congested queues, and wake up anyone who was waiting for requests to be
767 static inline void blk_clear_queue_congested(struct request_queue *q, int sync)
769 clear_bdi_congested(&q->backing_dev_info, sync);
773 * A queue has just entered congestion. Flag that in the queue's VM-visible
774 * state flags and increment the global gounter of congested queues.
776 static inline void blk_set_queue_congested(struct request_queue *q, int sync)
778 set_bdi_congested(&q->backing_dev_info, sync);
781 extern void blk_start_queue(struct request_queue *q);
782 extern void blk_stop_queue(struct request_queue *q);
783 extern void blk_sync_queue(struct request_queue *q);
784 extern void __blk_stop_queue(struct request_queue *q);
785 extern void __blk_run_queue(struct request_queue *q);
786 extern void blk_run_queue(struct request_queue *);
787 extern void blk_run_queue_async(struct request_queue *q);
788 extern int blk_rq_map_user(struct request_queue *, struct request *,
789 struct rq_map_data *, void __user *, unsigned long,
791 extern int blk_rq_unmap_user(struct bio *);
792 extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
793 extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
794 struct rq_map_data *, struct sg_iovec *, int,
795 unsigned int, gfp_t);
796 extern int blk_execute_rq(struct request_queue *, struct gendisk *,
797 struct request *, int);
798 extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
799 struct request *, int, rq_end_io_fn *);
801 static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
803 return bdev->bd_disk->queue;
807 * blk_rq_pos() : the current sector
808 * blk_rq_bytes() : bytes left in the entire request
809 * blk_rq_cur_bytes() : bytes left in the current segment
810 * blk_rq_err_bytes() : bytes left till the next error boundary
811 * blk_rq_sectors() : sectors left in the entire request
812 * blk_rq_cur_sectors() : sectors left in the current segment
814 static inline sector_t blk_rq_pos(const struct request *rq)
819 static inline unsigned int blk_rq_bytes(const struct request *rq)
821 return rq->__data_len;
824 static inline int blk_rq_cur_bytes(const struct request *rq)
826 return rq->bio ? bio_cur_bytes(rq->bio) : 0;
829 extern unsigned int blk_rq_err_bytes(const struct request *rq);
831 static inline unsigned int blk_rq_sectors(const struct request *rq)
833 return blk_rq_bytes(rq) >> 9;
836 static inline unsigned int blk_rq_cur_sectors(const struct request *rq)
838 return blk_rq_cur_bytes(rq) >> 9;
841 static inline unsigned int blk_queue_get_max_sectors(struct request_queue *q,
842 unsigned int cmd_flags)
844 if (unlikely(cmd_flags & REQ_DISCARD))
845 return min(q->limits.max_discard_sectors, UINT_MAX >> 9);
847 if (unlikely(cmd_flags & REQ_WRITE_SAME))
848 return q->limits.max_write_same_sectors;
850 return q->limits.max_sectors;
853 static inline unsigned int blk_rq_get_max_sectors(struct request *rq)
855 struct request_queue *q = rq->q;
857 if (unlikely(rq->cmd_type == REQ_TYPE_BLOCK_PC))
858 return q->limits.max_hw_sectors;
860 return blk_queue_get_max_sectors(q, rq->cmd_flags);
863 static inline unsigned int blk_rq_count_bios(struct request *rq)
865 unsigned int nr_bios = 0;
868 __rq_for_each_bio(bio, rq)
875 * Request issue related functions.
877 extern struct request *blk_peek_request(struct request_queue *q);
878 extern void blk_start_request(struct request *rq);
879 extern struct request *blk_fetch_request(struct request_queue *q);
882 * Request completion related functions.
884 * blk_update_request() completes given number of bytes and updates
885 * the request without completing it.
887 * blk_end_request() and friends. __blk_end_request() must be called
888 * with the request queue spinlock acquired.
890 * Several drivers define their own end_request and call
891 * blk_end_request() for parts of the original function.
892 * This prevents code duplication in drivers.
894 extern bool blk_update_request(struct request *rq, int error,
895 unsigned int nr_bytes);
896 extern bool blk_end_request(struct request *rq, int error,
897 unsigned int nr_bytes);
898 extern void blk_end_request_all(struct request *rq, int error);
899 extern bool blk_end_request_cur(struct request *rq, int error);
900 extern bool blk_end_request_err(struct request *rq, int error);
901 extern bool __blk_end_request(struct request *rq, int error,
902 unsigned int nr_bytes);
903 extern void __blk_end_request_all(struct request *rq, int error);
904 extern bool __blk_end_request_cur(struct request *rq, int error);
905 extern bool __blk_end_request_err(struct request *rq, int error);
907 extern void blk_complete_request(struct request *);
908 extern void __blk_complete_request(struct request *);
909 extern void blk_abort_request(struct request *);
910 extern void blk_unprep_request(struct request *);
913 * Access functions for manipulating queue properties
915 extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
916 spinlock_t *lock, int node_id);
917 extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
918 extern struct request_queue *blk_init_allocated_queue(struct request_queue *,
919 request_fn_proc *, spinlock_t *);
920 extern void blk_cleanup_queue(struct request_queue *);
921 extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
922 extern void blk_queue_bounce_limit(struct request_queue *, u64);
923 extern void blk_limits_max_hw_sectors(struct queue_limits *, unsigned int);
924 extern void blk_queue_max_hw_sectors(struct request_queue *, unsigned int);
925 extern void blk_queue_max_segments(struct request_queue *, unsigned short);
926 extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
927 extern void blk_queue_max_discard_sectors(struct request_queue *q,
928 unsigned int max_discard_sectors);
929 extern void blk_queue_max_write_same_sectors(struct request_queue *q,
930 unsigned int max_write_same_sectors);
931 extern void blk_queue_logical_block_size(struct request_queue *, unsigned short);
932 extern void blk_queue_physical_block_size(struct request_queue *, unsigned int);
933 extern void blk_queue_alignment_offset(struct request_queue *q,
934 unsigned int alignment);
935 extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min);
936 extern void blk_queue_io_min(struct request_queue *q, unsigned int min);
937 extern void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt);
938 extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt);
939 extern void blk_set_default_limits(struct queue_limits *lim);
940 extern void blk_set_stacking_limits(struct queue_limits *lim);
941 extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
943 extern int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
945 extern void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
947 extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
948 extern void blk_queue_dma_pad(struct request_queue *, unsigned int);
949 extern void blk_queue_update_dma_pad(struct request_queue *, unsigned int);
950 extern int blk_queue_dma_drain(struct request_queue *q,
951 dma_drain_needed_fn *dma_drain_needed,
952 void *buf, unsigned int size);
953 extern void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn);
954 extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
955 extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
956 extern void blk_queue_unprep_rq(struct request_queue *, unprep_rq_fn *ufn);
957 extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
958 extern void blk_queue_dma_alignment(struct request_queue *, int);
959 extern void blk_queue_update_dma_alignment(struct request_queue *, int);
960 extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
961 extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *);
962 extern void blk_queue_rq_timeout(struct request_queue *, unsigned int);
963 extern void blk_queue_flush(struct request_queue *q, unsigned int flush);
964 extern void blk_queue_flush_queueable(struct request_queue *q, bool queueable);
965 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
967 extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
968 extern int blk_bio_map_sg(struct request_queue *q, struct bio *bio,
969 struct scatterlist *sglist);
970 extern void blk_dump_rq_flags(struct request *, char *);
971 extern long nr_blockdev_pages(void);
973 bool __must_check blk_get_queue(struct request_queue *);
974 struct request_queue *blk_alloc_queue(gfp_t);
975 struct request_queue *blk_alloc_queue_node(gfp_t, int);
976 extern void blk_put_queue(struct request_queue *);
979 * block layer runtime pm functions
981 #ifdef CONFIG_PM_RUNTIME
982 extern void blk_pm_runtime_init(struct request_queue *q, struct device *dev);
983 extern int blk_pre_runtime_suspend(struct request_queue *q);
984 extern void blk_post_runtime_suspend(struct request_queue *q, int err);
985 extern void blk_pre_runtime_resume(struct request_queue *q);
986 extern void blk_post_runtime_resume(struct request_queue *q, int err);
988 static inline void blk_pm_runtime_init(struct request_queue *q,
989 struct device *dev) {}
990 static inline int blk_pre_runtime_suspend(struct request_queue *q)
994 static inline void blk_post_runtime_suspend(struct request_queue *q, int err) {}
995 static inline void blk_pre_runtime_resume(struct request_queue *q) {}
996 static inline void blk_post_runtime_resume(struct request_queue *q, int err) {}
1000 * blk_plug permits building a queue of related requests by holding the I/O
1001 * fragments for a short period. This allows merging of sequential requests
1002 * into single larger request. As the requests are moved from a per-task list to
1003 * the device's request_queue in a batch, this results in improved scalability
1004 * as the lock contention for request_queue lock is reduced.
1006 * It is ok not to disable preemption when adding the request to the plug list
1007 * or when attempting a merge, because blk_schedule_flush_list() will only flush
1008 * the plug list when the task sleeps by itself. For details, please see
1009 * schedule() where blk_schedule_flush_plug() is called.
1012 unsigned long magic; /* detect uninitialized use-cases */
1013 struct list_head list; /* requests */
1014 struct list_head cb_list; /* md requires an unplug callback */
1016 #define BLK_MAX_REQUEST_COUNT 16
1019 typedef void (*blk_plug_cb_fn)(struct blk_plug_cb *, bool);
1020 struct blk_plug_cb {
1021 struct list_head list;
1022 blk_plug_cb_fn callback;
1025 extern struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug,
1026 void *data, int size);
1027 extern void blk_start_plug(struct blk_plug *);
1028 extern void blk_finish_plug(struct blk_plug *);
1029 extern void blk_flush_plug_list(struct blk_plug *, bool);
1031 static inline void blk_flush_plug(struct task_struct *tsk)
1033 struct blk_plug *plug = tsk->plug;
1036 blk_flush_plug_list(plug, false);
1039 static inline void blk_schedule_flush_plug(struct task_struct *tsk)
1041 struct blk_plug *plug = tsk->plug;
1044 blk_flush_plug_list(plug, true);
1047 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
1049 struct blk_plug *plug = tsk->plug;
1051 return plug && (!list_empty(&plug->list) || !list_empty(&plug->cb_list));
1057 #define blk_rq_tagged(rq) ((rq)->cmd_flags & REQ_QUEUED)
1058 extern int blk_queue_start_tag(struct request_queue *, struct request *);
1059 extern struct request *blk_queue_find_tag(struct request_queue *, int);
1060 extern void blk_queue_end_tag(struct request_queue *, struct request *);
1061 extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *);
1062 extern void blk_queue_free_tags(struct request_queue *);
1063 extern int blk_queue_resize_tags(struct request_queue *, int);
1064 extern void blk_queue_invalidate_tags(struct request_queue *);
1065 extern struct blk_queue_tag *blk_init_tags(int);
1066 extern void blk_free_tags(struct blk_queue_tag *);
1068 static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
1071 if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
1073 return bqt->tag_index[tag];
1076 #define BLKDEV_DISCARD_SECURE 0x01 /* secure discard */
1078 extern int blkdev_issue_flush(struct block_device *, gfp_t, sector_t *);
1079 extern int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
1080 sector_t nr_sects, gfp_t gfp_mask, unsigned long flags);
1081 extern int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
1082 sector_t nr_sects, gfp_t gfp_mask, struct page *page);
1083 extern int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
1084 sector_t nr_sects, gfp_t gfp_mask);
1085 static inline int sb_issue_discard(struct super_block *sb, sector_t block,
1086 sector_t nr_blocks, gfp_t gfp_mask, unsigned long flags)
1088 return blkdev_issue_discard(sb->s_bdev, block << (sb->s_blocksize_bits - 9),
1089 nr_blocks << (sb->s_blocksize_bits - 9),
1092 static inline int sb_issue_zeroout(struct super_block *sb, sector_t block,
1093 sector_t nr_blocks, gfp_t gfp_mask)
1095 return blkdev_issue_zeroout(sb->s_bdev,
1096 block << (sb->s_blocksize_bits - 9),
1097 nr_blocks << (sb->s_blocksize_bits - 9),
1101 extern int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm);
1103 enum blk_default_limits {
1104 BLK_MAX_SEGMENTS = 128,
1105 BLK_SAFE_MAX_SECTORS = 255,
1106 BLK_DEF_MAX_SECTORS = 1024,
1107 BLK_MAX_SEGMENT_SIZE = 65536,
1108 BLK_SEG_BOUNDARY_MASK = 0xFFFFFFFFUL,
1111 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
1113 static inline unsigned long queue_bounce_pfn(struct request_queue *q)
1115 return q->limits.bounce_pfn;
1118 static inline unsigned long queue_segment_boundary(struct request_queue *q)
1120 return q->limits.seg_boundary_mask;
1123 static inline unsigned int queue_max_sectors(struct request_queue *q)
1125 return q->limits.max_sectors;
1128 static inline unsigned int queue_max_hw_sectors(struct request_queue *q)
1130 return q->limits.max_hw_sectors;
1133 static inline unsigned short queue_max_segments(struct request_queue *q)
1135 return q->limits.max_segments;
1138 static inline unsigned int queue_max_segment_size(struct request_queue *q)
1140 return q->limits.max_segment_size;
1143 static inline unsigned short queue_logical_block_size(struct request_queue *q)
1147 if (q && q->limits.logical_block_size)
1148 retval = q->limits.logical_block_size;
1153 static inline unsigned short bdev_logical_block_size(struct block_device *bdev)
1155 return queue_logical_block_size(bdev_get_queue(bdev));
1158 static inline unsigned int queue_physical_block_size(struct request_queue *q)
1160 return q->limits.physical_block_size;
1163 static inline unsigned int bdev_physical_block_size(struct block_device *bdev)
1165 return queue_physical_block_size(bdev_get_queue(bdev));
1168 static inline unsigned int queue_io_min(struct request_queue *q)
1170 return q->limits.io_min;
1173 static inline int bdev_io_min(struct block_device *bdev)
1175 return queue_io_min(bdev_get_queue(bdev));
1178 static inline unsigned int queue_io_opt(struct request_queue *q)
1180 return q->limits.io_opt;
1183 static inline int bdev_io_opt(struct block_device *bdev)
1185 return queue_io_opt(bdev_get_queue(bdev));
1188 static inline int queue_alignment_offset(struct request_queue *q)
1190 if (q->limits.misaligned)
1193 return q->limits.alignment_offset;
1196 static inline int queue_limit_alignment_offset(struct queue_limits *lim, sector_t sector)
1198 unsigned int granularity = max(lim->physical_block_size, lim->io_min);
1199 unsigned int alignment = (sector << 9) & (granularity - 1);
1201 return (granularity + lim->alignment_offset - alignment)
1202 & (granularity - 1);
1205 static inline int bdev_alignment_offset(struct block_device *bdev)
1207 struct request_queue *q = bdev_get_queue(bdev);
1209 if (q->limits.misaligned)
1212 if (bdev != bdev->bd_contains)
1213 return bdev->bd_part->alignment_offset;
1215 return q->limits.alignment_offset;
1218 static inline int queue_discard_alignment(struct request_queue *q)
1220 if (q->limits.discard_misaligned)
1223 return q->limits.discard_alignment;
1226 static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector_t sector)
1228 unsigned int alignment, granularity, offset;
1230 if (!lim->max_discard_sectors)
1233 /* Why are these in bytes, not sectors? */
1234 alignment = lim->discard_alignment >> 9;
1235 granularity = lim->discard_granularity >> 9;
1239 /* Offset of the partition start in 'granularity' sectors */
1240 offset = sector_div(sector, granularity);
1242 /* And why do we do this modulus *again* in blkdev_issue_discard()? */
1243 offset = (granularity + alignment - offset) % granularity;
1245 /* Turn it back into bytes, gaah */
1249 static inline int bdev_discard_alignment(struct block_device *bdev)
1251 struct request_queue *q = bdev_get_queue(bdev);
1253 if (bdev != bdev->bd_contains)
1254 return bdev->bd_part->discard_alignment;
1256 return q->limits.discard_alignment;
1259 static inline unsigned int queue_discard_zeroes_data(struct request_queue *q)
1261 if (q->limits.max_discard_sectors && q->limits.discard_zeroes_data == 1)
1267 static inline unsigned int bdev_discard_zeroes_data(struct block_device *bdev)
1269 return queue_discard_zeroes_data(bdev_get_queue(bdev));
1272 static inline unsigned int bdev_write_same(struct block_device *bdev)
1274 struct request_queue *q = bdev_get_queue(bdev);
1277 return q->limits.max_write_same_sectors;
1282 static inline int queue_dma_alignment(struct request_queue *q)
1284 return q ? q->dma_alignment : 511;
1287 static inline int blk_rq_aligned(struct request_queue *q, unsigned long addr,
1290 unsigned int alignment = queue_dma_alignment(q) | q->dma_pad_mask;
1291 return !(addr & alignment) && !(len & alignment);
1294 /* assumes size > 256 */
1295 static inline unsigned int blksize_bits(unsigned int size)
1297 unsigned int bits = 8;
1301 } while (size > 256);
1305 static inline unsigned int block_size(struct block_device *bdev)
1307 return bdev->bd_block_size;
1310 static inline bool queue_flush_queueable(struct request_queue *q)
1312 return !q->flush_not_queueable;
1315 typedef struct {struct page *v;} Sector;
1317 unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
1319 static inline void put_dev_sector(Sector p)
1321 page_cache_release(p.v);
1325 int kblockd_schedule_work(struct request_queue *q, struct work_struct *work);
1327 #ifdef CONFIG_BLK_CGROUP
1329 * This should not be using sched_clock(). A real patch is in progress
1330 * to fix this up, until that is in place we need to disable preemption
1331 * around sched_clock() in this function and set_io_start_time_ns().
1333 static inline void set_start_time_ns(struct request *req)
1336 req->start_time_ns = sched_clock();
1340 static inline void set_io_start_time_ns(struct request *req)
1343 req->io_start_time_ns = sched_clock();
1347 static inline uint64_t rq_start_time_ns(struct request *req)
1349 return req->start_time_ns;
1352 static inline uint64_t rq_io_start_time_ns(struct request *req)
1354 return req->io_start_time_ns;
1357 static inline void set_start_time_ns(struct request *req) {}
1358 static inline void set_io_start_time_ns(struct request *req) {}
1359 static inline uint64_t rq_start_time_ns(struct request *req)
1363 static inline uint64_t rq_io_start_time_ns(struct request *req)
1369 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
1370 MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
1371 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
1372 MODULE_ALIAS("block-major-" __stringify(major) "-*")
1374 #if defined(CONFIG_BLK_DEV_INTEGRITY)
1376 #define INTEGRITY_FLAG_READ 2 /* verify data integrity on read */
1377 #define INTEGRITY_FLAG_WRITE 4 /* generate data integrity on write */
1379 struct blk_integrity_exchg {
1383 unsigned int data_size;
1384 unsigned short sector_size;
1385 const char *disk_name;
1388 typedef void (integrity_gen_fn) (struct blk_integrity_exchg *);
1389 typedef int (integrity_vrfy_fn) (struct blk_integrity_exchg *);
1390 typedef void (integrity_set_tag_fn) (void *, void *, unsigned int);
1391 typedef void (integrity_get_tag_fn) (void *, void *, unsigned int);
1393 struct blk_integrity {
1394 integrity_gen_fn *generate_fn;
1395 integrity_vrfy_fn *verify_fn;
1396 integrity_set_tag_fn *set_tag_fn;
1397 integrity_get_tag_fn *get_tag_fn;
1399 unsigned short flags;
1400 unsigned short tuple_size;
1401 unsigned short sector_size;
1402 unsigned short tag_size;
1406 struct kobject kobj;
1409 extern bool blk_integrity_is_initialized(struct gendisk *);
1410 extern int blk_integrity_register(struct gendisk *, struct blk_integrity *);
1411 extern void blk_integrity_unregister(struct gendisk *);
1412 extern int blk_integrity_compare(struct gendisk *, struct gendisk *);
1413 extern int blk_rq_map_integrity_sg(struct request_queue *, struct bio *,
1414 struct scatterlist *);
1415 extern int blk_rq_count_integrity_sg(struct request_queue *, struct bio *);
1416 extern int blk_integrity_merge_rq(struct request_queue *, struct request *,
1418 extern int blk_integrity_merge_bio(struct request_queue *, struct request *,
1422 struct blk_integrity *bdev_get_integrity(struct block_device *bdev)
1424 return bdev->bd_disk->integrity;
1427 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1429 return disk->integrity;
1432 static inline int blk_integrity_rq(struct request *rq)
1434 if (rq->bio == NULL)
1437 return bio_integrity(rq->bio);
1440 static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1443 q->limits.max_integrity_segments = segs;
1446 static inline unsigned short
1447 queue_max_integrity_segments(struct request_queue *q)
1449 return q->limits.max_integrity_segments;
1452 #else /* CONFIG_BLK_DEV_INTEGRITY */
1455 struct block_device;
1457 struct blk_integrity;
1459 static inline int blk_integrity_rq(struct request *rq)
1463 static inline int blk_rq_count_integrity_sg(struct request_queue *q,
1468 static inline int blk_rq_map_integrity_sg(struct request_queue *q,
1470 struct scatterlist *s)
1474 static inline struct blk_integrity *bdev_get_integrity(struct block_device *b)
1478 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1482 static inline int blk_integrity_compare(struct gendisk *a, struct gendisk *b)
1486 static inline int blk_integrity_register(struct gendisk *d,
1487 struct blk_integrity *b)
1491 static inline void blk_integrity_unregister(struct gendisk *d)
1494 static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1498 static inline unsigned short queue_max_integrity_segments(struct request_queue *q)
1502 static inline int blk_integrity_merge_rq(struct request_queue *rq,
1508 static inline int blk_integrity_merge_bio(struct request_queue *rq,
1514 static inline bool blk_integrity_is_initialized(struct gendisk *g)
1519 #endif /* CONFIG_BLK_DEV_INTEGRITY */
1521 struct block_device_operations {
1522 int (*open) (struct block_device *, fmode_t);
1523 void (*release) (struct gendisk *, fmode_t);
1524 int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1525 int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1526 int (*direct_access) (struct block_device *, sector_t,
1527 void **, unsigned long *);
1528 unsigned int (*check_events) (struct gendisk *disk,
1529 unsigned int clearing);
1530 /* ->media_changed() is DEPRECATED, use ->check_events() instead */
1531 int (*media_changed) (struct gendisk *);
1532 void (*unlock_native_capacity) (struct gendisk *);
1533 int (*revalidate_disk) (struct gendisk *);
1534 int (*getgeo)(struct block_device *, struct hd_geometry *);
1535 /* this callback is with swap_lock and sometimes page table lock held */
1536 void (*swap_slot_free_notify) (struct block_device *, unsigned long);
1537 struct module *owner;
1540 extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int,
1542 #else /* CONFIG_BLOCK */
1544 * stubs for when the block layer is configured out
1546 #define buffer_heads_over_limit 0
1548 static inline long nr_blockdev_pages(void)
1556 static inline void blk_start_plug(struct blk_plug *plug)
1560 static inline void blk_finish_plug(struct blk_plug *plug)
1564 static inline void blk_flush_plug(struct task_struct *task)
1568 static inline void blk_schedule_flush_plug(struct task_struct *task)
1573 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
1578 #endif /* CONFIG_BLOCK */