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;
102 unsigned int cmd_flags;
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;
165 void *special; /* opaque pointer available for LLD use */
166 char *buffer; /* kaddr of the current segment if available */
172 * when request is used as a packet command carrier
174 unsigned char __cmd[BLK_MAX_CDB];
176 unsigned short cmd_len;
178 unsigned int extra_len; /* length of alignment and padding */
179 unsigned int sense_len;
180 unsigned int resid_len; /* residual count */
183 unsigned long deadline;
184 struct list_head timeout_list;
185 unsigned int timeout;
189 * completion callback.
191 rq_end_io_fn *end_io;
195 struct request *next_rq;
198 static inline unsigned short req_get_ioprio(struct request *req)
204 * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
205 * requests. Some step values could eventually be made generic.
207 struct request_pm_state
209 /* PM state machine step value, currently driver specific */
211 /* requested PM state value (S1, S2, S3, S4, ...) */
213 void* data; /* for driver use */
216 #include <linux/elevator.h>
218 typedef void (request_fn_proc) (struct request_queue *q);
219 typedef void (make_request_fn) (struct request_queue *q, struct bio *bio);
220 typedef int (prep_rq_fn) (struct request_queue *, struct request *);
221 typedef void (unprep_rq_fn) (struct request_queue *, struct request *);
224 struct bvec_merge_data {
225 struct block_device *bi_bdev;
230 typedef int (merge_bvec_fn) (struct request_queue *, struct bvec_merge_data *,
232 typedef void (softirq_done_fn)(struct request *);
233 typedef int (dma_drain_needed_fn)(struct request *);
234 typedef int (lld_busy_fn) (struct request_queue *q);
235 typedef int (bsg_job_fn) (struct bsg_job *);
237 enum blk_eh_timer_return {
243 typedef enum blk_eh_timer_return (rq_timed_out_fn)(struct request *);
245 enum blk_queue_state {
250 struct blk_queue_tag {
251 struct request **tag_index; /* map of busy tags */
252 unsigned long *tag_map; /* bit map of free/busy tags */
253 int busy; /* current depth */
254 int max_depth; /* what we will send to device */
255 int real_max_depth; /* what the array can hold */
256 atomic_t refcnt; /* map can be shared */
259 #define BLK_SCSI_MAX_CMDS (256)
260 #define BLK_SCSI_CMD_PER_LONG (BLK_SCSI_MAX_CMDS / (sizeof(long) * 8))
262 struct queue_limits {
263 unsigned long bounce_pfn;
264 unsigned long seg_boundary_mask;
266 unsigned int max_hw_sectors;
267 unsigned int max_sectors;
268 unsigned int max_segment_size;
269 unsigned int physical_block_size;
270 unsigned int alignment_offset;
273 unsigned int max_discard_sectors;
274 unsigned int max_write_same_sectors;
275 unsigned int discard_granularity;
276 unsigned int discard_alignment;
278 unsigned short logical_block_size;
279 unsigned short max_segments;
280 unsigned short max_integrity_segments;
282 unsigned char misaligned;
283 unsigned char discard_misaligned;
284 unsigned char cluster;
285 unsigned char discard_zeroes_data;
288 struct request_queue {
290 * Together with queue_head for cacheline sharing
292 struct list_head queue_head;
293 struct request *last_merge;
294 struct elevator_queue *elevator;
295 int nr_rqs[2]; /* # allocated [a]sync rqs */
296 int nr_rqs_elvpriv; /* # allocated rqs w/ elvpriv */
299 * If blkcg is not used, @q->root_rl serves all requests. If blkcg
300 * is used, root blkg allocates from @q->root_rl and all other
301 * blkgs from their own blkg->rl. Which one to use should be
302 * determined using bio_request_list().
304 struct request_list root_rl;
306 request_fn_proc *request_fn;
307 make_request_fn *make_request_fn;
308 prep_rq_fn *prep_rq_fn;
309 unprep_rq_fn *unprep_rq_fn;
310 merge_bvec_fn *merge_bvec_fn;
311 softirq_done_fn *softirq_done_fn;
312 rq_timed_out_fn *rq_timed_out_fn;
313 dma_drain_needed_fn *dma_drain_needed;
314 lld_busy_fn *lld_busy_fn;
317 * Dispatch queue sorting
320 struct request *boundary_rq;
323 * Delayed queue handling
325 struct delayed_work delay_work;
327 struct backing_dev_info backing_dev_info;
330 * The queue owner gets to use this for whatever they like.
331 * ll_rw_blk doesn't touch it.
336 * various queue flags, see QUEUE_* below
338 unsigned long queue_flags;
341 * ida allocated id for this queue. Used to index queues from
347 * queue needs bounce pages for pages above this limit
352 * protects queue structures from reentrancy. ->__queue_lock should
353 * _never_ be used directly, it is queue private. always use
356 spinlock_t __queue_lock;
357 spinlock_t *queue_lock;
364 #ifdef CONFIG_PM_RUNTIME
367 unsigned int nr_pending;
373 unsigned long nr_requests; /* Max # of requests */
374 unsigned int nr_congestion_on;
375 unsigned int nr_congestion_off;
376 unsigned int nr_batching;
378 unsigned int dma_drain_size;
379 void *dma_drain_buffer;
380 unsigned int dma_pad_mask;
381 unsigned int dma_alignment;
383 struct blk_queue_tag *queue_tags;
384 struct list_head tag_busy_list;
386 unsigned int nr_sorted;
387 unsigned int in_flight[2];
389 * Number of active block driver functions for which blk_drain_queue()
390 * must wait. Must be incremented around functions that unlock the
391 * queue_lock internally, e.g. scsi_request_fn().
393 unsigned int request_fn_active;
395 unsigned int rq_timeout;
396 struct timer_list timeout;
397 struct list_head timeout_list;
399 struct list_head icq_list;
400 #ifdef CONFIG_BLK_CGROUP
401 DECLARE_BITMAP (blkcg_pols, BLKCG_MAX_POLS);
402 struct blkcg_gq *root_blkg;
403 struct list_head blkg_list;
406 struct queue_limits limits;
411 unsigned int sg_timeout;
412 unsigned int sg_reserved_size;
414 #ifdef CONFIG_BLK_DEV_IO_TRACE
415 struct blk_trace *blk_trace;
418 * for flush operations
420 unsigned int flush_flags;
421 unsigned int flush_not_queueable:1;
422 unsigned int flush_queue_delayed:1;
423 unsigned int flush_pending_idx:1;
424 unsigned int flush_running_idx:1;
425 unsigned long flush_pending_since;
426 struct list_head flush_queue[2];
427 struct list_head flush_data_in_flight;
428 struct request flush_rq;
430 struct mutex sysfs_lock;
434 #if defined(CONFIG_BLK_DEV_BSG)
435 bsg_job_fn *bsg_job_fn;
437 struct bsg_class_device bsg_dev;
440 #ifdef CONFIG_BLK_CGROUP
441 struct list_head all_q_node;
443 #ifdef CONFIG_BLK_DEV_THROTTLING
445 struct throtl_data *td;
447 struct rcu_head rcu_head;
450 #define QUEUE_FLAG_QUEUED 1 /* uses generic tag queueing */
451 #define QUEUE_FLAG_STOPPED 2 /* queue is stopped */
452 #define QUEUE_FLAG_SYNCFULL 3 /* read queue has been filled */
453 #define QUEUE_FLAG_ASYNCFULL 4 /* write queue has been filled */
454 #define QUEUE_FLAG_DYING 5 /* queue being torn down */
455 #define QUEUE_FLAG_BYPASS 6 /* act as dumb FIFO queue */
456 #define QUEUE_FLAG_BIDI 7 /* queue supports bidi requests */
457 #define QUEUE_FLAG_NOMERGES 8 /* disable merge attempts */
458 #define QUEUE_FLAG_SAME_COMP 9 /* complete on same CPU-group */
459 #define QUEUE_FLAG_FAIL_IO 10 /* fake timeout */
460 #define QUEUE_FLAG_STACKABLE 11 /* supports request stacking */
461 #define QUEUE_FLAG_NONROT 12 /* non-rotational device (SSD) */
462 #define QUEUE_FLAG_VIRT QUEUE_FLAG_NONROT /* paravirt device */
463 #define QUEUE_FLAG_IO_STAT 13 /* do IO stats */
464 #define QUEUE_FLAG_DISCARD 14 /* supports DISCARD */
465 #define QUEUE_FLAG_NOXMERGES 15 /* No extended merges */
466 #define QUEUE_FLAG_ADD_RANDOM 16 /* Contributes to random pool */
467 #define QUEUE_FLAG_SECDISCARD 17 /* supports SECDISCARD */
468 #define QUEUE_FLAG_SAME_FORCE 18 /* force complete on same CPU */
469 #define QUEUE_FLAG_DEAD 19 /* queue tear-down finished */
471 #define QUEUE_FLAG_DEFAULT ((1 << QUEUE_FLAG_IO_STAT) | \
472 (1 << QUEUE_FLAG_STACKABLE) | \
473 (1 << QUEUE_FLAG_SAME_COMP) | \
474 (1 << QUEUE_FLAG_ADD_RANDOM))
476 static inline void queue_lockdep_assert_held(struct request_queue *q)
479 lockdep_assert_held(q->queue_lock);
482 static inline void queue_flag_set_unlocked(unsigned int flag,
483 struct request_queue *q)
485 __set_bit(flag, &q->queue_flags);
488 static inline int queue_flag_test_and_clear(unsigned int flag,
489 struct request_queue *q)
491 queue_lockdep_assert_held(q);
493 if (test_bit(flag, &q->queue_flags)) {
494 __clear_bit(flag, &q->queue_flags);
501 static inline int queue_flag_test_and_set(unsigned int flag,
502 struct request_queue *q)
504 queue_lockdep_assert_held(q);
506 if (!test_bit(flag, &q->queue_flags)) {
507 __set_bit(flag, &q->queue_flags);
514 static inline void queue_flag_set(unsigned int flag, struct request_queue *q)
516 queue_lockdep_assert_held(q);
517 __set_bit(flag, &q->queue_flags);
520 static inline void queue_flag_clear_unlocked(unsigned int flag,
521 struct request_queue *q)
523 __clear_bit(flag, &q->queue_flags);
526 static inline int queue_in_flight(struct request_queue *q)
528 return q->in_flight[0] + q->in_flight[1];
531 static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
533 queue_lockdep_assert_held(q);
534 __clear_bit(flag, &q->queue_flags);
537 #define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
538 #define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
539 #define blk_queue_dying(q) test_bit(QUEUE_FLAG_DYING, &(q)->queue_flags)
540 #define blk_queue_dead(q) test_bit(QUEUE_FLAG_DEAD, &(q)->queue_flags)
541 #define blk_queue_bypass(q) test_bit(QUEUE_FLAG_BYPASS, &(q)->queue_flags)
542 #define blk_queue_nomerges(q) test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
543 #define blk_queue_noxmerges(q) \
544 test_bit(QUEUE_FLAG_NOXMERGES, &(q)->queue_flags)
545 #define blk_queue_nonrot(q) test_bit(QUEUE_FLAG_NONROT, &(q)->queue_flags)
546 #define blk_queue_io_stat(q) test_bit(QUEUE_FLAG_IO_STAT, &(q)->queue_flags)
547 #define blk_queue_add_random(q) test_bit(QUEUE_FLAG_ADD_RANDOM, &(q)->queue_flags)
548 #define blk_queue_stackable(q) \
549 test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags)
550 #define blk_queue_discard(q) test_bit(QUEUE_FLAG_DISCARD, &(q)->queue_flags)
551 #define blk_queue_secdiscard(q) (blk_queue_discard(q) && \
552 test_bit(QUEUE_FLAG_SECDISCARD, &(q)->queue_flags))
554 #define blk_noretry_request(rq) \
555 ((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \
556 REQ_FAILFAST_DRIVER))
558 #define blk_account_rq(rq) \
559 (((rq)->cmd_flags & REQ_STARTED) && \
560 ((rq)->cmd_type == REQ_TYPE_FS))
562 #define blk_pm_request(rq) \
563 ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND || \
564 (rq)->cmd_type == REQ_TYPE_PM_RESUME)
566 #define blk_rq_cpu_valid(rq) ((rq)->cpu != -1)
567 #define blk_bidi_rq(rq) ((rq)->next_rq != NULL)
568 /* rq->queuelist of dequeued request must be list_empty() */
569 #define blk_queued_rq(rq) (!list_empty(&(rq)->queuelist))
571 #define list_entry_rq(ptr) list_entry((ptr), struct request, queuelist)
573 #define rq_data_dir(rq) ((rq)->cmd_flags & 1)
575 static inline unsigned int blk_queue_cluster(struct request_queue *q)
577 return q->limits.cluster;
581 * We regard a request as sync, if either a read or a sync write
583 static inline bool rw_is_sync(unsigned int rw_flags)
585 return !(rw_flags & REQ_WRITE) || (rw_flags & REQ_SYNC);
588 static inline bool rq_is_sync(struct request *rq)
590 return rw_is_sync(rq->cmd_flags);
593 static inline bool blk_rl_full(struct request_list *rl, bool sync)
595 unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
597 return rl->flags & flag;
600 static inline void blk_set_rl_full(struct request_list *rl, bool sync)
602 unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
607 static inline void blk_clear_rl_full(struct request_list *rl, bool sync)
609 unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
614 static inline bool rq_mergeable(struct request *rq)
616 if (rq->cmd_type != REQ_TYPE_FS)
619 if (rq->cmd_flags & REQ_NOMERGE_FLAGS)
625 static inline bool blk_check_merge_flags(unsigned int flags1,
628 if ((flags1 & REQ_DISCARD) != (flags2 & REQ_DISCARD))
631 if ((flags1 & REQ_SECURE) != (flags2 & REQ_SECURE))
634 if ((flags1 & REQ_WRITE_SAME) != (flags2 & REQ_WRITE_SAME))
640 static inline bool blk_write_same_mergeable(struct bio *a, struct bio *b)
642 if (bio_data(a) == bio_data(b))
649 * q->prep_rq_fn return values
651 #define BLKPREP_OK 0 /* serve it */
652 #define BLKPREP_KILL 1 /* fatal error, kill */
653 #define BLKPREP_DEFER 2 /* leave on queue */
655 extern unsigned long blk_max_low_pfn, blk_max_pfn;
658 * standard bounce addresses:
660 * BLK_BOUNCE_HIGH : bounce all highmem pages
661 * BLK_BOUNCE_ANY : don't bounce anything
662 * BLK_BOUNCE_ISA : bounce pages above ISA DMA boundary
665 #if BITS_PER_LONG == 32
666 #define BLK_BOUNCE_HIGH ((u64)blk_max_low_pfn << PAGE_SHIFT)
668 #define BLK_BOUNCE_HIGH -1ULL
670 #define BLK_BOUNCE_ANY (-1ULL)
671 #define BLK_BOUNCE_ISA (DMA_BIT_MASK(24))
674 * default timeout for SG_IO if none specified
676 #define BLK_DEFAULT_SG_TIMEOUT (60 * HZ)
677 #define BLK_MIN_SG_TIMEOUT (7 * HZ)
680 extern int init_emergency_isa_pool(void);
681 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
683 static inline int init_emergency_isa_pool(void)
687 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
690 #endif /* CONFIG_MMU */
696 unsigned long offset;
701 struct req_iterator {
706 /* This should not be used directly - use rq_for_each_segment */
707 #define for_each_bio(_bio) \
708 for (; _bio; _bio = _bio->bi_next)
709 #define __rq_for_each_bio(_bio, rq) \
711 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
713 #define rq_for_each_segment(bvl, _rq, _iter) \
714 __rq_for_each_bio(_iter.bio, _rq) \
715 bio_for_each_segment(bvl, _iter.bio, _iter.i)
717 #define rq_iter_last(rq, _iter) \
718 (_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)
720 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
721 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
723 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
724 extern void rq_flush_dcache_pages(struct request *rq);
726 static inline void rq_flush_dcache_pages(struct request *rq)
731 extern int blk_register_queue(struct gendisk *disk);
732 extern void blk_unregister_queue(struct gendisk *disk);
733 extern void generic_make_request(struct bio *bio);
734 extern void blk_rq_init(struct request_queue *q, struct request *rq);
735 extern void blk_put_request(struct request *);
736 extern void __blk_put_request(struct request_queue *, struct request *);
737 extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
738 extern struct request *blk_make_request(struct request_queue *, struct bio *,
740 extern void blk_requeue_request(struct request_queue *, struct request *);
741 extern void blk_add_request_payload(struct request *rq, struct page *page,
743 extern int blk_rq_check_limits(struct request_queue *q, struct request *rq);
744 extern int blk_lld_busy(struct request_queue *q);
745 extern int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
746 struct bio_set *bs, gfp_t gfp_mask,
747 int (*bio_ctr)(struct bio *, struct bio *, void *),
749 extern void blk_rq_unprep_clone(struct request *rq);
750 extern int blk_insert_cloned_request(struct request_queue *q,
752 extern void blk_delay_queue(struct request_queue *, unsigned long);
753 extern void blk_recount_segments(struct request_queue *, struct bio *);
754 extern int scsi_verify_blk_ioctl(struct block_device *, unsigned int);
755 extern int scsi_cmd_blk_ioctl(struct block_device *, fmode_t,
756 unsigned int, void __user *);
757 extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t,
758 unsigned int, void __user *);
759 extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t,
760 struct scsi_ioctl_command __user *);
762 extern void blk_queue_bio(struct request_queue *q, struct bio *bio);
765 * A queue has just exitted congestion. Note this in the global counter of
766 * congested queues, and wake up anyone who was waiting for requests to be
769 static inline void blk_clear_queue_congested(struct request_queue *q, int sync)
771 clear_bdi_congested(&q->backing_dev_info, sync);
775 * A queue has just entered congestion. Flag that in the queue's VM-visible
776 * state flags and increment the global gounter of congested queues.
778 static inline void blk_set_queue_congested(struct request_queue *q, int sync)
780 set_bdi_congested(&q->backing_dev_info, sync);
783 extern void blk_start_queue(struct request_queue *q);
784 extern void blk_stop_queue(struct request_queue *q);
785 extern void blk_sync_queue(struct request_queue *q);
786 extern void __blk_stop_queue(struct request_queue *q);
787 extern void __blk_run_queue(struct request_queue *q);
788 extern void blk_run_queue(struct request_queue *);
789 extern void blk_run_queue_async(struct request_queue *q);
790 extern int blk_rq_map_user(struct request_queue *, struct request *,
791 struct rq_map_data *, void __user *, unsigned long,
793 extern int blk_rq_unmap_user(struct bio *);
794 extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
795 extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
796 struct rq_map_data *, struct sg_iovec *, int,
797 unsigned int, gfp_t);
798 extern int blk_execute_rq(struct request_queue *, struct gendisk *,
799 struct request *, int);
800 extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
801 struct request *, int, rq_end_io_fn *);
803 static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
805 return bdev->bd_disk->queue;
809 * blk_rq_pos() : the current sector
810 * blk_rq_bytes() : bytes left in the entire request
811 * blk_rq_cur_bytes() : bytes left in the current segment
812 * blk_rq_err_bytes() : bytes left till the next error boundary
813 * blk_rq_sectors() : sectors left in the entire request
814 * blk_rq_cur_sectors() : sectors left in the current segment
816 static inline sector_t blk_rq_pos(const struct request *rq)
821 static inline unsigned int blk_rq_bytes(const struct request *rq)
823 return rq->__data_len;
826 static inline int blk_rq_cur_bytes(const struct request *rq)
828 return rq->bio ? bio_cur_bytes(rq->bio) : 0;
831 extern unsigned int blk_rq_err_bytes(const struct request *rq);
833 static inline unsigned int blk_rq_sectors(const struct request *rq)
835 return blk_rq_bytes(rq) >> 9;
838 static inline unsigned int blk_rq_cur_sectors(const struct request *rq)
840 return blk_rq_cur_bytes(rq) >> 9;
843 static inline unsigned int blk_queue_get_max_sectors(struct request_queue *q,
844 unsigned int cmd_flags)
846 if (unlikely(cmd_flags & REQ_DISCARD))
847 return min(q->limits.max_discard_sectors, UINT_MAX >> 9);
849 if (unlikely(cmd_flags & REQ_WRITE_SAME))
850 return q->limits.max_write_same_sectors;
852 return q->limits.max_sectors;
855 static inline unsigned int blk_rq_get_max_sectors(struct request *rq)
857 struct request_queue *q = rq->q;
859 if (unlikely(rq->cmd_type == REQ_TYPE_BLOCK_PC))
860 return q->limits.max_hw_sectors;
862 return blk_queue_get_max_sectors(q, rq->cmd_flags);
865 static inline unsigned int blk_rq_count_bios(struct request *rq)
867 unsigned int nr_bios = 0;
870 __rq_for_each_bio(bio, rq)
877 * Request issue related functions.
879 extern struct request *blk_peek_request(struct request_queue *q);
880 extern void blk_start_request(struct request *rq);
881 extern struct request *blk_fetch_request(struct request_queue *q);
884 * Request completion related functions.
886 * blk_update_request() completes given number of bytes and updates
887 * the request without completing it.
889 * blk_end_request() and friends. __blk_end_request() must be called
890 * with the request queue spinlock acquired.
892 * Several drivers define their own end_request and call
893 * blk_end_request() for parts of the original function.
894 * This prevents code duplication in drivers.
896 extern bool blk_update_request(struct request *rq, int error,
897 unsigned int nr_bytes);
898 extern bool blk_end_request(struct request *rq, int error,
899 unsigned int nr_bytes);
900 extern void blk_end_request_all(struct request *rq, int error);
901 extern bool blk_end_request_cur(struct request *rq, int error);
902 extern bool blk_end_request_err(struct request *rq, int error);
903 extern bool __blk_end_request(struct request *rq, int error,
904 unsigned int nr_bytes);
905 extern void __blk_end_request_all(struct request *rq, int error);
906 extern bool __blk_end_request_cur(struct request *rq, int error);
907 extern bool __blk_end_request_err(struct request *rq, int error);
909 extern void blk_complete_request(struct request *);
910 extern void __blk_complete_request(struct request *);
911 extern void blk_abort_request(struct request *);
912 extern void blk_unprep_request(struct request *);
915 * Access functions for manipulating queue properties
917 extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
918 spinlock_t *lock, int node_id);
919 extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
920 extern struct request_queue *blk_init_allocated_queue(struct request_queue *,
921 request_fn_proc *, spinlock_t *);
922 extern void blk_cleanup_queue(struct request_queue *);
923 extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
924 extern void blk_queue_bounce_limit(struct request_queue *, u64);
925 extern void blk_limits_max_hw_sectors(struct queue_limits *, unsigned int);
926 extern void blk_queue_max_hw_sectors(struct request_queue *, unsigned int);
927 extern void blk_queue_max_segments(struct request_queue *, unsigned short);
928 extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
929 extern void blk_queue_max_discard_sectors(struct request_queue *q,
930 unsigned int max_discard_sectors);
931 extern void blk_queue_max_write_same_sectors(struct request_queue *q,
932 unsigned int max_write_same_sectors);
933 extern void blk_queue_logical_block_size(struct request_queue *, unsigned short);
934 extern void blk_queue_physical_block_size(struct request_queue *, unsigned int);
935 extern void blk_queue_alignment_offset(struct request_queue *q,
936 unsigned int alignment);
937 extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min);
938 extern void blk_queue_io_min(struct request_queue *q, unsigned int min);
939 extern void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt);
940 extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt);
941 extern void blk_set_default_limits(struct queue_limits *lim);
942 extern void blk_set_stacking_limits(struct queue_limits *lim);
943 extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
945 extern int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
947 extern void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
949 extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
950 extern void blk_queue_dma_pad(struct request_queue *, unsigned int);
951 extern void blk_queue_update_dma_pad(struct request_queue *, unsigned int);
952 extern int blk_queue_dma_drain(struct request_queue *q,
953 dma_drain_needed_fn *dma_drain_needed,
954 void *buf, unsigned int size);
955 extern void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn);
956 extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
957 extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
958 extern void blk_queue_unprep_rq(struct request_queue *, unprep_rq_fn *ufn);
959 extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
960 extern void blk_queue_dma_alignment(struct request_queue *, int);
961 extern void blk_queue_update_dma_alignment(struct request_queue *, int);
962 extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
963 extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *);
964 extern void blk_queue_rq_timeout(struct request_queue *, unsigned int);
965 extern void blk_queue_flush(struct request_queue *q, unsigned int flush);
966 extern void blk_queue_flush_queueable(struct request_queue *q, bool queueable);
967 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
969 extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
970 extern int blk_bio_map_sg(struct request_queue *q, struct bio *bio,
971 struct scatterlist *sglist);
972 extern void blk_dump_rq_flags(struct request *, char *);
973 extern long nr_blockdev_pages(void);
975 bool __must_check blk_get_queue(struct request_queue *);
976 struct request_queue *blk_alloc_queue(gfp_t);
977 struct request_queue *blk_alloc_queue_node(gfp_t, int);
978 extern void blk_put_queue(struct request_queue *);
981 * block layer runtime pm functions
983 #ifdef CONFIG_PM_RUNTIME
984 extern void blk_pm_runtime_init(struct request_queue *q, struct device *dev);
985 extern int blk_pre_runtime_suspend(struct request_queue *q);
986 extern void blk_post_runtime_suspend(struct request_queue *q, int err);
987 extern void blk_pre_runtime_resume(struct request_queue *q);
988 extern void blk_post_runtime_resume(struct request_queue *q, int err);
990 static inline void blk_pm_runtime_init(struct request_queue *q,
991 struct device *dev) {}
992 static inline int blk_pre_runtime_suspend(struct request_queue *q)
996 static inline void blk_post_runtime_suspend(struct request_queue *q, int err) {}
997 static inline void blk_pre_runtime_resume(struct request_queue *q) {}
998 static inline void blk_post_runtime_resume(struct request_queue *q, int err) {}
1002 * blk_plug permits building a queue of related requests by holding the I/O
1003 * fragments for a short period. This allows merging of sequential requests
1004 * into single larger request. As the requests are moved from a per-task list to
1005 * the device's request_queue in a batch, this results in improved scalability
1006 * as the lock contention for request_queue lock is reduced.
1008 * It is ok not to disable preemption when adding the request to the plug list
1009 * or when attempting a merge, because blk_schedule_flush_list() will only flush
1010 * the plug list when the task sleeps by itself. For details, please see
1011 * schedule() where blk_schedule_flush_plug() is called.
1014 unsigned long magic; /* detect uninitialized use-cases */
1015 struct list_head list; /* requests */
1016 struct list_head cb_list; /* md requires an unplug callback */
1018 #define BLK_MAX_REQUEST_COUNT 16
1021 typedef void (*blk_plug_cb_fn)(struct blk_plug_cb *, bool);
1022 struct blk_plug_cb {
1023 struct list_head list;
1024 blk_plug_cb_fn callback;
1027 extern struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug,
1028 void *data, int size);
1029 extern void blk_start_plug(struct blk_plug *);
1030 extern void blk_finish_plug(struct blk_plug *);
1031 extern void blk_flush_plug_list(struct blk_plug *, bool);
1033 static inline void blk_flush_plug(struct task_struct *tsk)
1035 struct blk_plug *plug = tsk->plug;
1038 blk_flush_plug_list(plug, false);
1041 static inline void blk_schedule_flush_plug(struct task_struct *tsk)
1043 struct blk_plug *plug = tsk->plug;
1046 blk_flush_plug_list(plug, true);
1049 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
1051 struct blk_plug *plug = tsk->plug;
1053 return plug && (!list_empty(&plug->list) || !list_empty(&plug->cb_list));
1059 #define blk_rq_tagged(rq) ((rq)->cmd_flags & REQ_QUEUED)
1060 extern int blk_queue_start_tag(struct request_queue *, struct request *);
1061 extern struct request *blk_queue_find_tag(struct request_queue *, int);
1062 extern void blk_queue_end_tag(struct request_queue *, struct request *);
1063 extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *);
1064 extern void blk_queue_free_tags(struct request_queue *);
1065 extern int blk_queue_resize_tags(struct request_queue *, int);
1066 extern void blk_queue_invalidate_tags(struct request_queue *);
1067 extern struct blk_queue_tag *blk_init_tags(int);
1068 extern void blk_free_tags(struct blk_queue_tag *);
1070 static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
1073 if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
1075 return bqt->tag_index[tag];
1078 #define BLKDEV_DISCARD_SECURE 0x01 /* secure discard */
1080 extern int blkdev_issue_flush(struct block_device *, gfp_t, sector_t *);
1081 extern int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
1082 sector_t nr_sects, gfp_t gfp_mask, unsigned long flags);
1083 extern int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
1084 sector_t nr_sects, gfp_t gfp_mask, struct page *page);
1085 extern int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
1086 sector_t nr_sects, gfp_t gfp_mask);
1087 static inline int sb_issue_discard(struct super_block *sb, sector_t block,
1088 sector_t nr_blocks, gfp_t gfp_mask, unsigned long flags)
1090 return blkdev_issue_discard(sb->s_bdev, block << (sb->s_blocksize_bits - 9),
1091 nr_blocks << (sb->s_blocksize_bits - 9),
1094 static inline int sb_issue_zeroout(struct super_block *sb, sector_t block,
1095 sector_t nr_blocks, gfp_t gfp_mask)
1097 return blkdev_issue_zeroout(sb->s_bdev,
1098 block << (sb->s_blocksize_bits - 9),
1099 nr_blocks << (sb->s_blocksize_bits - 9),
1103 extern int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm);
1105 enum blk_default_limits {
1106 BLK_MAX_SEGMENTS = 128,
1107 BLK_SAFE_MAX_SECTORS = 255,
1108 BLK_DEF_MAX_SECTORS = 1024,
1109 BLK_MAX_SEGMENT_SIZE = 65536,
1110 BLK_SEG_BOUNDARY_MASK = 0xFFFFFFFFUL,
1113 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
1115 static inline unsigned long queue_bounce_pfn(struct request_queue *q)
1117 return q->limits.bounce_pfn;
1120 static inline unsigned long queue_segment_boundary(struct request_queue *q)
1122 return q->limits.seg_boundary_mask;
1125 static inline unsigned int queue_max_sectors(struct request_queue *q)
1127 return q->limits.max_sectors;
1130 static inline unsigned int queue_max_hw_sectors(struct request_queue *q)
1132 return q->limits.max_hw_sectors;
1135 static inline unsigned short queue_max_segments(struct request_queue *q)
1137 return q->limits.max_segments;
1140 static inline unsigned int queue_max_segment_size(struct request_queue *q)
1142 return q->limits.max_segment_size;
1145 static inline unsigned short queue_logical_block_size(struct request_queue *q)
1149 if (q && q->limits.logical_block_size)
1150 retval = q->limits.logical_block_size;
1155 static inline unsigned short bdev_logical_block_size(struct block_device *bdev)
1157 return queue_logical_block_size(bdev_get_queue(bdev));
1160 static inline unsigned int queue_physical_block_size(struct request_queue *q)
1162 return q->limits.physical_block_size;
1165 static inline unsigned int bdev_physical_block_size(struct block_device *bdev)
1167 return queue_physical_block_size(bdev_get_queue(bdev));
1170 static inline unsigned int queue_io_min(struct request_queue *q)
1172 return q->limits.io_min;
1175 static inline int bdev_io_min(struct block_device *bdev)
1177 return queue_io_min(bdev_get_queue(bdev));
1180 static inline unsigned int queue_io_opt(struct request_queue *q)
1182 return q->limits.io_opt;
1185 static inline int bdev_io_opt(struct block_device *bdev)
1187 return queue_io_opt(bdev_get_queue(bdev));
1190 static inline int queue_alignment_offset(struct request_queue *q)
1192 if (q->limits.misaligned)
1195 return q->limits.alignment_offset;
1198 static inline int queue_limit_alignment_offset(struct queue_limits *lim, sector_t sector)
1200 unsigned int granularity = max(lim->physical_block_size, lim->io_min);
1201 unsigned int alignment = (sector << 9) & (granularity - 1);
1203 return (granularity + lim->alignment_offset - alignment)
1204 & (granularity - 1);
1207 static inline int bdev_alignment_offset(struct block_device *bdev)
1209 struct request_queue *q = bdev_get_queue(bdev);
1211 if (q->limits.misaligned)
1214 if (bdev != bdev->bd_contains)
1215 return bdev->bd_part->alignment_offset;
1217 return q->limits.alignment_offset;
1220 static inline int queue_discard_alignment(struct request_queue *q)
1222 if (q->limits.discard_misaligned)
1225 return q->limits.discard_alignment;
1228 static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector_t sector)
1230 unsigned int alignment, granularity, offset;
1232 if (!lim->max_discard_sectors)
1235 /* Why are these in bytes, not sectors? */
1236 alignment = lim->discard_alignment >> 9;
1237 granularity = lim->discard_granularity >> 9;
1241 /* Offset of the partition start in 'granularity' sectors */
1242 offset = sector_div(sector, granularity);
1244 /* And why do we do this modulus *again* in blkdev_issue_discard()? */
1245 offset = (granularity + alignment - offset) % granularity;
1247 /* Turn it back into bytes, gaah */
1251 static inline int bdev_discard_alignment(struct block_device *bdev)
1253 struct request_queue *q = bdev_get_queue(bdev);
1255 if (bdev != bdev->bd_contains)
1256 return bdev->bd_part->discard_alignment;
1258 return q->limits.discard_alignment;
1261 static inline unsigned int queue_discard_zeroes_data(struct request_queue *q)
1263 if (q->limits.max_discard_sectors && q->limits.discard_zeroes_data == 1)
1269 static inline unsigned int bdev_discard_zeroes_data(struct block_device *bdev)
1271 return queue_discard_zeroes_data(bdev_get_queue(bdev));
1274 static inline unsigned int bdev_write_same(struct block_device *bdev)
1276 struct request_queue *q = bdev_get_queue(bdev);
1279 return q->limits.max_write_same_sectors;
1284 static inline int queue_dma_alignment(struct request_queue *q)
1286 return q ? q->dma_alignment : 511;
1289 static inline int blk_rq_aligned(struct request_queue *q, unsigned long addr,
1292 unsigned int alignment = queue_dma_alignment(q) | q->dma_pad_mask;
1293 return !(addr & alignment) && !(len & alignment);
1296 /* assumes size > 256 */
1297 static inline unsigned int blksize_bits(unsigned int size)
1299 unsigned int bits = 8;
1303 } while (size > 256);
1307 static inline unsigned int block_size(struct block_device *bdev)
1309 return bdev->bd_block_size;
1312 static inline bool queue_flush_queueable(struct request_queue *q)
1314 return !q->flush_not_queueable;
1317 typedef struct {struct page *v;} Sector;
1319 unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
1321 static inline void put_dev_sector(Sector p)
1323 page_cache_release(p.v);
1327 int kblockd_schedule_work(struct request_queue *q, struct work_struct *work);
1329 #ifdef CONFIG_BLK_CGROUP
1331 * This should not be using sched_clock(). A real patch is in progress
1332 * to fix this up, until that is in place we need to disable preemption
1333 * around sched_clock() in this function and set_io_start_time_ns().
1335 static inline void set_start_time_ns(struct request *req)
1338 req->start_time_ns = sched_clock();
1342 static inline void set_io_start_time_ns(struct request *req)
1345 req->io_start_time_ns = sched_clock();
1349 static inline uint64_t rq_start_time_ns(struct request *req)
1351 return req->start_time_ns;
1354 static inline uint64_t rq_io_start_time_ns(struct request *req)
1356 return req->io_start_time_ns;
1359 static inline void set_start_time_ns(struct request *req) {}
1360 static inline void set_io_start_time_ns(struct request *req) {}
1361 static inline uint64_t rq_start_time_ns(struct request *req)
1365 static inline uint64_t rq_io_start_time_ns(struct request *req)
1371 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
1372 MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
1373 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
1374 MODULE_ALIAS("block-major-" __stringify(major) "-*")
1376 #if defined(CONFIG_BLK_DEV_INTEGRITY)
1378 #define INTEGRITY_FLAG_READ 2 /* verify data integrity on read */
1379 #define INTEGRITY_FLAG_WRITE 4 /* generate data integrity on write */
1381 struct blk_integrity_exchg {
1385 unsigned int data_size;
1386 unsigned short sector_size;
1387 const char *disk_name;
1390 typedef void (integrity_gen_fn) (struct blk_integrity_exchg *);
1391 typedef int (integrity_vrfy_fn) (struct blk_integrity_exchg *);
1392 typedef void (integrity_set_tag_fn) (void *, void *, unsigned int);
1393 typedef void (integrity_get_tag_fn) (void *, void *, unsigned int);
1395 struct blk_integrity {
1396 integrity_gen_fn *generate_fn;
1397 integrity_vrfy_fn *verify_fn;
1398 integrity_set_tag_fn *set_tag_fn;
1399 integrity_get_tag_fn *get_tag_fn;
1401 unsigned short flags;
1402 unsigned short tuple_size;
1403 unsigned short sector_size;
1404 unsigned short tag_size;
1408 struct kobject kobj;
1411 extern bool blk_integrity_is_initialized(struct gendisk *);
1412 extern int blk_integrity_register(struct gendisk *, struct blk_integrity *);
1413 extern void blk_integrity_unregister(struct gendisk *);
1414 extern int blk_integrity_compare(struct gendisk *, struct gendisk *);
1415 extern int blk_rq_map_integrity_sg(struct request_queue *, struct bio *,
1416 struct scatterlist *);
1417 extern int blk_rq_count_integrity_sg(struct request_queue *, struct bio *);
1418 extern int blk_integrity_merge_rq(struct request_queue *, struct request *,
1420 extern int blk_integrity_merge_bio(struct request_queue *, struct request *,
1424 struct blk_integrity *bdev_get_integrity(struct block_device *bdev)
1426 return bdev->bd_disk->integrity;
1429 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1431 return disk->integrity;
1434 static inline int blk_integrity_rq(struct request *rq)
1436 if (rq->bio == NULL)
1439 return bio_integrity(rq->bio);
1442 static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1445 q->limits.max_integrity_segments = segs;
1448 static inline unsigned short
1449 queue_max_integrity_segments(struct request_queue *q)
1451 return q->limits.max_integrity_segments;
1454 #else /* CONFIG_BLK_DEV_INTEGRITY */
1457 struct block_device;
1459 struct blk_integrity;
1461 static inline int blk_integrity_rq(struct request *rq)
1465 static inline int blk_rq_count_integrity_sg(struct request_queue *q,
1470 static inline int blk_rq_map_integrity_sg(struct request_queue *q,
1472 struct scatterlist *s)
1476 static inline struct blk_integrity *bdev_get_integrity(struct block_device *b)
1480 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1484 static inline int blk_integrity_compare(struct gendisk *a, struct gendisk *b)
1488 static inline int blk_integrity_register(struct gendisk *d,
1489 struct blk_integrity *b)
1493 static inline void blk_integrity_unregister(struct gendisk *d)
1496 static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1500 static inline unsigned short queue_max_integrity_segments(struct request_queue *q)
1504 static inline int blk_integrity_merge_rq(struct request_queue *rq,
1510 static inline int blk_integrity_merge_bio(struct request_queue *rq,
1516 static inline bool blk_integrity_is_initialized(struct gendisk *g)
1521 #endif /* CONFIG_BLK_DEV_INTEGRITY */
1523 struct block_device_operations {
1524 int (*open) (struct block_device *, fmode_t);
1525 void (*release) (struct gendisk *, fmode_t);
1526 int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1527 int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1528 int (*direct_access) (struct block_device *, sector_t,
1529 void **, unsigned long *);
1530 unsigned int (*check_events) (struct gendisk *disk,
1531 unsigned int clearing);
1532 /* ->media_changed() is DEPRECATED, use ->check_events() instead */
1533 int (*media_changed) (struct gendisk *);
1534 void (*unlock_native_capacity) (struct gendisk *);
1535 int (*revalidate_disk) (struct gendisk *);
1536 int (*getgeo)(struct block_device *, struct hd_geometry *);
1537 /* this callback is with swap_lock and sometimes page table lock held */
1538 void (*swap_slot_free_notify) (struct block_device *, unsigned long);
1539 struct module *owner;
1542 extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int,
1544 #else /* CONFIG_BLOCK */
1546 * stubs for when the block layer is configured out
1548 #define buffer_heads_over_limit 0
1550 static inline long nr_blockdev_pages(void)
1558 static inline void blk_start_plug(struct blk_plug *plug)
1562 static inline void blk_finish_plug(struct blk_plug *plug)
1566 static inline void blk_flush_plug(struct task_struct *task)
1570 static inline void blk_schedule_flush_plug(struct task_struct *task)
1575 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
1580 #endif /* CONFIG_BLOCK */