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/llist.h>
12 #include <linux/timer.h>
13 #include <linux/workqueue.h>
14 #include <linux/pagemap.h>
15 #include <linux/backing-dev-defs.h>
16 #include <linux/wait.h>
17 #include <linux/mempool.h>
18 #include <linux/bio.h>
19 #include <linux/stringify.h>
20 #include <linux/gfp.h>
21 #include <linux/bsg.h>
22 #include <linux/smp.h>
23 #include <linux/rcupdate.h>
24 #include <linux/percpu-refcount.h>
26 #include <asm/scatterlist.h>
29 struct scsi_ioctl_command;
32 struct elevator_queue;
38 struct blk_flush_queue;
40 #define BLKDEV_MIN_RQ 4
41 #define BLKDEV_MAX_RQ 128 /* Default maximum */
44 * Maximum number of blkcg policies allowed to be registered concurrently.
45 * Defined here to simplify include dependency.
47 #define BLKCG_MAX_POLS 2
50 typedef void (rq_end_io_fn)(struct request *, int);
52 #define BLK_RL_SYNCFULL (1U << 0)
53 #define BLK_RL_ASYNCFULL (1U << 1)
56 struct request_queue *q; /* the queue this rl belongs to */
57 #ifdef CONFIG_BLK_CGROUP
58 struct blkcg_gq *blkg; /* blkg this request pool belongs to */
61 * count[], starved[], and wait[] are indexed by
62 * BLK_RW_SYNC/BLK_RW_ASYNC
67 wait_queue_head_t wait[2];
72 * request command types
74 enum rq_cmd_type_bits {
75 REQ_TYPE_FS = 1, /* fs request */
76 REQ_TYPE_BLOCK_PC, /* scsi command */
77 REQ_TYPE_DRV_PRIV, /* driver defined types from here */
80 #define BLK_MAX_CDB 16
83 * Try to put the fields that are referenced together in the same cacheline.
85 * If you modify this structure, make sure to update blk_rq_init() and
86 * especially blk_mq_rq_ctx_init() to take care of the added fields.
89 struct list_head queuelist;
91 struct call_single_data csd;
92 unsigned long fifo_time;
95 struct request_queue *q;
96 struct blk_mq_ctx *mq_ctx;
100 unsigned long atomic_flags;
104 /* the following two fields are internal, NEVER access directly */
105 unsigned int __data_len; /* total data len */
106 sector_t __sector; /* sector cursor */
112 * The hash is used inside the scheduler, and killed once the
113 * request reaches the dispatch list. The ipi_list is only used
114 * to queue the request for softirq completion, which is long
115 * after the request has been unhashed (and even removed from
116 * the dispatch list).
119 struct hlist_node hash; /* merge hash */
120 struct list_head ipi_list;
124 * The rb_node is only used inside the io scheduler, requests
125 * are pruned when moved to the dispatch queue. So let the
126 * completion_data share space with the rb_node.
129 struct rb_node rb_node; /* sort/lookup */
130 void *completion_data;
134 * Three pointers are available for the IO schedulers, if they need
135 * more they have to dynamically allocate it. Flush requests are
136 * never put on the IO scheduler. So let the flush fields share
137 * space with the elevator data.
147 struct list_head list;
148 rq_end_io_fn *saved_end_io;
152 struct gendisk *rq_disk;
153 struct hd_struct *part;
154 unsigned long start_time;
155 #ifdef CONFIG_BLK_CGROUP
156 struct request_list *rl; /* rl this rq is alloced from */
157 unsigned long long start_time_ns;
158 unsigned long long io_start_time_ns; /* when passed to hardware */
160 /* Number of scatter-gather DMA addr+len pairs after
161 * physical address coalescing is performed.
163 unsigned short nr_phys_segments;
164 #if defined(CONFIG_BLK_DEV_INTEGRITY)
165 unsigned short nr_integrity_segments;
168 unsigned short ioprio;
170 void *special; /* opaque pointer available for LLD use */
176 * when request is used as a packet command carrier
178 unsigned char __cmd[BLK_MAX_CDB];
180 unsigned short cmd_len;
182 unsigned int extra_len; /* length of alignment and padding */
183 unsigned int sense_len;
184 unsigned int resid_len; /* residual count */
187 unsigned long deadline;
188 struct list_head timeout_list;
189 unsigned int timeout;
193 * completion callback.
195 rq_end_io_fn *end_io;
199 struct request *next_rq;
202 static inline unsigned short req_get_ioprio(struct request *req)
207 #include <linux/elevator.h>
209 struct blk_queue_ctx;
211 typedef void (request_fn_proc) (struct request_queue *q);
212 typedef void (make_request_fn) (struct request_queue *q, struct bio *bio);
213 typedef int (prep_rq_fn) (struct request_queue *, struct request *);
214 typedef void (unprep_rq_fn) (struct request_queue *, struct request *);
217 struct bvec_merge_data {
218 struct block_device *bi_bdev;
223 typedef int (merge_bvec_fn) (struct request_queue *, struct bvec_merge_data *,
225 typedef void (softirq_done_fn)(struct request *);
226 typedef int (dma_drain_needed_fn)(struct request *);
227 typedef int (lld_busy_fn) (struct request_queue *q);
228 typedef int (bsg_job_fn) (struct bsg_job *);
230 enum blk_eh_timer_return {
236 typedef enum blk_eh_timer_return (rq_timed_out_fn)(struct request *);
238 enum blk_queue_state {
243 struct blk_queue_tag {
244 struct request **tag_index; /* map of busy tags */
245 unsigned long *tag_map; /* bit map of free/busy tags */
246 int busy; /* current depth */
247 int max_depth; /* what we will send to device */
248 int real_max_depth; /* what the array can hold */
249 atomic_t refcnt; /* map can be shared */
250 int alloc_policy; /* tag allocation policy */
251 int next_tag; /* next tag */
253 #define BLK_TAG_ALLOC_FIFO 0 /* allocate starting from 0 */
254 #define BLK_TAG_ALLOC_RR 1 /* allocate starting from last allocated tag */
256 #define BLK_SCSI_MAX_CMDS (256)
257 #define BLK_SCSI_CMD_PER_LONG (BLK_SCSI_MAX_CMDS / (sizeof(long) * 8))
259 struct queue_limits {
260 unsigned long bounce_pfn;
261 unsigned long seg_boundary_mask;
263 unsigned int max_hw_sectors;
264 unsigned int chunk_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;
284 unsigned char raid_partial_stripes_expensive;
287 struct request_queue {
289 * Together with queue_head for cacheline sharing
291 struct list_head queue_head;
292 struct request *last_merge;
293 struct elevator_queue *elevator;
294 int nr_rqs[2]; /* # allocated [a]sync rqs */
295 int nr_rqs_elvpriv; /* # allocated rqs w/ elvpriv */
298 * If blkcg is not used, @q->root_rl serves all requests. If blkcg
299 * is used, root blkg allocates from @q->root_rl and all other
300 * blkgs from their own blkg->rl. Which one to use should be
301 * determined using bio_request_list().
303 struct request_list root_rl;
305 request_fn_proc *request_fn;
306 make_request_fn *make_request_fn;
307 prep_rq_fn *prep_rq_fn;
308 unprep_rq_fn *unprep_rq_fn;
309 merge_bvec_fn *merge_bvec_fn;
310 softirq_done_fn *softirq_done_fn;
311 rq_timed_out_fn *rq_timed_out_fn;
312 dma_drain_needed_fn *dma_drain_needed;
313 lld_busy_fn *lld_busy_fn;
315 struct blk_mq_ops *mq_ops;
317 unsigned int *mq_map;
320 struct blk_mq_ctx __percpu *queue_ctx;
321 unsigned int nr_queues;
323 /* hw dispatch queues */
324 struct blk_mq_hw_ctx **queue_hw_ctx;
325 unsigned int nr_hw_queues;
328 * Dispatch queue sorting
331 struct request *boundary_rq;
334 * Delayed queue handling
336 struct delayed_work delay_work;
338 struct backing_dev_info backing_dev_info;
341 * The queue owner gets to use this for whatever they like.
342 * ll_rw_blk doesn't touch it.
347 * various queue flags, see QUEUE_* below
349 unsigned long queue_flags;
352 * ida allocated id for this queue. Used to index queues from
358 * queue needs bounce pages for pages above this limit
363 * protects queue structures from reentrancy. ->__queue_lock should
364 * _never_ be used directly, it is queue private. always use
367 spinlock_t __queue_lock;
368 spinlock_t *queue_lock;
378 struct kobject mq_kobj;
383 unsigned int nr_pending;
389 unsigned long nr_requests; /* Max # of requests */
390 unsigned int nr_congestion_on;
391 unsigned int nr_congestion_off;
392 unsigned int nr_batching;
394 unsigned int dma_drain_size;
395 void *dma_drain_buffer;
396 unsigned int dma_pad_mask;
397 unsigned int dma_alignment;
399 struct blk_queue_tag *queue_tags;
400 struct list_head tag_busy_list;
402 unsigned int nr_sorted;
403 unsigned int in_flight[2];
405 * Number of active block driver functions for which blk_drain_queue()
406 * must wait. Must be incremented around functions that unlock the
407 * queue_lock internally, e.g. scsi_request_fn().
409 unsigned int request_fn_active;
411 unsigned int rq_timeout;
412 struct timer_list timeout;
413 struct list_head timeout_list;
415 struct list_head icq_list;
416 #ifdef CONFIG_BLK_CGROUP
417 DECLARE_BITMAP (blkcg_pols, BLKCG_MAX_POLS);
418 struct blkcg_gq *root_blkg;
419 struct list_head blkg_list;
422 struct queue_limits limits;
427 unsigned int sg_timeout;
428 unsigned int sg_reserved_size;
430 #ifdef CONFIG_BLK_DEV_IO_TRACE
431 struct blk_trace *blk_trace;
434 * for flush operations
436 unsigned int flush_flags;
437 unsigned int flush_not_queueable:1;
438 struct blk_flush_queue *fq;
440 struct list_head requeue_list;
441 spinlock_t requeue_lock;
442 struct work_struct requeue_work;
444 struct mutex sysfs_lock;
447 atomic_t mq_freeze_depth;
449 #if defined(CONFIG_BLK_DEV_BSG)
450 bsg_job_fn *bsg_job_fn;
452 struct bsg_class_device bsg_dev;
455 #ifdef CONFIG_BLK_DEV_THROTTLING
457 struct throtl_data *td;
459 struct rcu_head rcu_head;
460 wait_queue_head_t mq_freeze_wq;
461 struct percpu_ref mq_usage_counter;
462 struct list_head all_q_node;
464 struct blk_mq_tag_set *tag_set;
465 struct list_head tag_set_list;
468 #define QUEUE_FLAG_QUEUED 1 /* uses generic tag queueing */
469 #define QUEUE_FLAG_STOPPED 2 /* queue is stopped */
470 #define QUEUE_FLAG_SYNCFULL 3 /* read queue has been filled */
471 #define QUEUE_FLAG_ASYNCFULL 4 /* write queue has been filled */
472 #define QUEUE_FLAG_DYING 5 /* queue being torn down */
473 #define QUEUE_FLAG_BYPASS 6 /* act as dumb FIFO queue */
474 #define QUEUE_FLAG_BIDI 7 /* queue supports bidi requests */
475 #define QUEUE_FLAG_NOMERGES 8 /* disable merge attempts */
476 #define QUEUE_FLAG_SAME_COMP 9 /* complete on same CPU-group */
477 #define QUEUE_FLAG_FAIL_IO 10 /* fake timeout */
478 #define QUEUE_FLAG_STACKABLE 11 /* supports request stacking */
479 #define QUEUE_FLAG_NONROT 12 /* non-rotational device (SSD) */
480 #define QUEUE_FLAG_VIRT QUEUE_FLAG_NONROT /* paravirt device */
481 #define QUEUE_FLAG_IO_STAT 13 /* do IO stats */
482 #define QUEUE_FLAG_DISCARD 14 /* supports DISCARD */
483 #define QUEUE_FLAG_NOXMERGES 15 /* No extended merges */
484 #define QUEUE_FLAG_ADD_RANDOM 16 /* Contributes to random pool */
485 #define QUEUE_FLAG_SECDISCARD 17 /* supports SECDISCARD */
486 #define QUEUE_FLAG_SAME_FORCE 18 /* force complete on same CPU */
487 #define QUEUE_FLAG_DEAD 19 /* queue tear-down finished */
488 #define QUEUE_FLAG_INIT_DONE 20 /* queue is initialized */
489 #define QUEUE_FLAG_NO_SG_MERGE 21 /* don't attempt to merge SG segments*/
490 #define QUEUE_FLAG_SG_GAPS 22 /* queue doesn't support SG gaps */
492 #define QUEUE_FLAG_DEFAULT ((1 << QUEUE_FLAG_IO_STAT) | \
493 (1 << QUEUE_FLAG_STACKABLE) | \
494 (1 << QUEUE_FLAG_SAME_COMP) | \
495 (1 << QUEUE_FLAG_ADD_RANDOM))
497 #define QUEUE_FLAG_MQ_DEFAULT ((1 << QUEUE_FLAG_IO_STAT) | \
498 (1 << QUEUE_FLAG_STACKABLE) | \
499 (1 << QUEUE_FLAG_SAME_COMP))
501 static inline void queue_lockdep_assert_held(struct request_queue *q)
504 lockdep_assert_held(q->queue_lock);
507 static inline void queue_flag_set_unlocked(unsigned int flag,
508 struct request_queue *q)
510 __set_bit(flag, &q->queue_flags);
513 static inline int queue_flag_test_and_clear(unsigned int flag,
514 struct request_queue *q)
516 queue_lockdep_assert_held(q);
518 if (test_bit(flag, &q->queue_flags)) {
519 __clear_bit(flag, &q->queue_flags);
526 static inline int queue_flag_test_and_set(unsigned int flag,
527 struct request_queue *q)
529 queue_lockdep_assert_held(q);
531 if (!test_bit(flag, &q->queue_flags)) {
532 __set_bit(flag, &q->queue_flags);
539 static inline void queue_flag_set(unsigned int flag, struct request_queue *q)
541 queue_lockdep_assert_held(q);
542 __set_bit(flag, &q->queue_flags);
545 static inline void queue_flag_clear_unlocked(unsigned int flag,
546 struct request_queue *q)
548 __clear_bit(flag, &q->queue_flags);
551 static inline int queue_in_flight(struct request_queue *q)
553 return q->in_flight[0] + q->in_flight[1];
556 static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
558 queue_lockdep_assert_held(q);
559 __clear_bit(flag, &q->queue_flags);
562 #define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
563 #define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
564 #define blk_queue_dying(q) test_bit(QUEUE_FLAG_DYING, &(q)->queue_flags)
565 #define blk_queue_dead(q) test_bit(QUEUE_FLAG_DEAD, &(q)->queue_flags)
566 #define blk_queue_bypass(q) test_bit(QUEUE_FLAG_BYPASS, &(q)->queue_flags)
567 #define blk_queue_init_done(q) test_bit(QUEUE_FLAG_INIT_DONE, &(q)->queue_flags)
568 #define blk_queue_nomerges(q) test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
569 #define blk_queue_noxmerges(q) \
570 test_bit(QUEUE_FLAG_NOXMERGES, &(q)->queue_flags)
571 #define blk_queue_nonrot(q) test_bit(QUEUE_FLAG_NONROT, &(q)->queue_flags)
572 #define blk_queue_io_stat(q) test_bit(QUEUE_FLAG_IO_STAT, &(q)->queue_flags)
573 #define blk_queue_add_random(q) test_bit(QUEUE_FLAG_ADD_RANDOM, &(q)->queue_flags)
574 #define blk_queue_stackable(q) \
575 test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags)
576 #define blk_queue_discard(q) test_bit(QUEUE_FLAG_DISCARD, &(q)->queue_flags)
577 #define blk_queue_secdiscard(q) (blk_queue_discard(q) && \
578 test_bit(QUEUE_FLAG_SECDISCARD, &(q)->queue_flags))
580 #define blk_noretry_request(rq) \
581 ((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \
582 REQ_FAILFAST_DRIVER))
584 #define blk_account_rq(rq) \
585 (((rq)->cmd_flags & REQ_STARTED) && \
586 ((rq)->cmd_type == REQ_TYPE_FS))
588 #define blk_rq_cpu_valid(rq) ((rq)->cpu != -1)
589 #define blk_bidi_rq(rq) ((rq)->next_rq != NULL)
590 /* rq->queuelist of dequeued request must be list_empty() */
591 #define blk_queued_rq(rq) (!list_empty(&(rq)->queuelist))
593 #define list_entry_rq(ptr) list_entry((ptr), struct request, queuelist)
595 #define rq_data_dir(rq) (((rq)->cmd_flags & 1) != 0)
598 * Driver can handle struct request, if it either has an old style
599 * request_fn defined, or is blk-mq based.
601 static inline bool queue_is_rq_based(struct request_queue *q)
603 return q->request_fn || q->mq_ops;
606 static inline unsigned int blk_queue_cluster(struct request_queue *q)
608 return q->limits.cluster;
612 * We regard a request as sync, if either a read or a sync write
614 static inline bool rw_is_sync(unsigned int rw_flags)
616 return !(rw_flags & REQ_WRITE) || (rw_flags & REQ_SYNC);
619 static inline bool rq_is_sync(struct request *rq)
621 return rw_is_sync(rq->cmd_flags);
624 static inline bool blk_rl_full(struct request_list *rl, bool sync)
626 unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
628 return rl->flags & flag;
631 static inline void blk_set_rl_full(struct request_list *rl, bool sync)
633 unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
638 static inline void blk_clear_rl_full(struct request_list *rl, bool sync)
640 unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
645 static inline bool rq_mergeable(struct request *rq)
647 if (rq->cmd_type != REQ_TYPE_FS)
650 if (rq->cmd_flags & REQ_NOMERGE_FLAGS)
656 static inline bool blk_check_merge_flags(unsigned int flags1,
659 if ((flags1 & REQ_DISCARD) != (flags2 & REQ_DISCARD))
662 if ((flags1 & REQ_SECURE) != (flags2 & REQ_SECURE))
665 if ((flags1 & REQ_WRITE_SAME) != (flags2 & REQ_WRITE_SAME))
671 static inline bool blk_write_same_mergeable(struct bio *a, struct bio *b)
673 if (bio_data(a) == bio_data(b))
680 * q->prep_rq_fn return values
682 #define BLKPREP_OK 0 /* serve it */
683 #define BLKPREP_KILL 1 /* fatal error, kill */
684 #define BLKPREP_DEFER 2 /* leave on queue */
686 extern unsigned long blk_max_low_pfn, blk_max_pfn;
689 * standard bounce addresses:
691 * BLK_BOUNCE_HIGH : bounce all highmem pages
692 * BLK_BOUNCE_ANY : don't bounce anything
693 * BLK_BOUNCE_ISA : bounce pages above ISA DMA boundary
696 #if BITS_PER_LONG == 32
697 #define BLK_BOUNCE_HIGH ((u64)blk_max_low_pfn << PAGE_SHIFT)
699 #define BLK_BOUNCE_HIGH -1ULL
701 #define BLK_BOUNCE_ANY (-1ULL)
702 #define BLK_BOUNCE_ISA (DMA_BIT_MASK(24))
705 * default timeout for SG_IO if none specified
707 #define BLK_DEFAULT_SG_TIMEOUT (60 * HZ)
708 #define BLK_MIN_SG_TIMEOUT (7 * HZ)
711 extern int init_emergency_isa_pool(void);
712 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
714 static inline int init_emergency_isa_pool(void)
718 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
721 #endif /* CONFIG_MMU */
727 unsigned long offset;
732 struct req_iterator {
733 struct bvec_iter iter;
737 /* This should not be used directly - use rq_for_each_segment */
738 #define for_each_bio(_bio) \
739 for (; _bio; _bio = _bio->bi_next)
740 #define __rq_for_each_bio(_bio, rq) \
742 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
744 #define rq_for_each_segment(bvl, _rq, _iter) \
745 __rq_for_each_bio(_iter.bio, _rq) \
746 bio_for_each_segment(bvl, _iter.bio, _iter.iter)
748 #define rq_iter_last(bvec, _iter) \
749 (_iter.bio->bi_next == NULL && \
750 bio_iter_last(bvec, _iter.iter))
752 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
753 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
755 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
756 extern void rq_flush_dcache_pages(struct request *rq);
758 static inline void rq_flush_dcache_pages(struct request *rq)
763 extern int blk_register_queue(struct gendisk *disk);
764 extern void blk_unregister_queue(struct gendisk *disk);
765 extern void generic_make_request(struct bio *bio);
766 extern void blk_rq_init(struct request_queue *q, struct request *rq);
767 extern void blk_put_request(struct request *);
768 extern void __blk_put_request(struct request_queue *, struct request *);
769 extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
770 extern struct request *blk_make_request(struct request_queue *, struct bio *,
772 extern void blk_rq_set_block_pc(struct request *);
773 extern void blk_requeue_request(struct request_queue *, struct request *);
774 extern void blk_add_request_payload(struct request *rq, struct page *page,
776 extern int blk_rq_check_limits(struct request_queue *q, struct request *rq);
777 extern int blk_lld_busy(struct request_queue *q);
778 extern void blk_rq_prep_clone(struct request *rq, struct request *rq_src);
779 extern int blk_insert_cloned_request(struct request_queue *q,
781 extern void blk_delay_queue(struct request_queue *, unsigned long);
782 extern void blk_recount_segments(struct request_queue *, struct bio *);
783 extern int scsi_verify_blk_ioctl(struct block_device *, unsigned int);
784 extern int scsi_cmd_blk_ioctl(struct block_device *, fmode_t,
785 unsigned int, void __user *);
786 extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t,
787 unsigned int, void __user *);
788 extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t,
789 struct scsi_ioctl_command __user *);
791 extern void blk_queue_bio(struct request_queue *q, struct bio *bio);
793 extern void blk_start_queue(struct request_queue *q);
794 extern void blk_stop_queue(struct request_queue *q);
795 extern void blk_sync_queue(struct request_queue *q);
796 extern void __blk_stop_queue(struct request_queue *q);
797 extern void __blk_run_queue(struct request_queue *q);
798 extern void __blk_run_queue_uncond(struct request_queue *q);
799 extern void blk_run_queue(struct request_queue *);
800 extern void blk_run_queue_async(struct request_queue *q);
801 extern int blk_rq_map_user(struct request_queue *, struct request *,
802 struct rq_map_data *, void __user *, unsigned long,
804 extern int blk_rq_unmap_user(struct bio *);
805 extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
806 extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
807 struct rq_map_data *, const struct iov_iter *,
809 extern int blk_execute_rq(struct request_queue *, struct gendisk *,
810 struct request *, int);
811 extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
812 struct request *, int, rq_end_io_fn *);
814 static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
816 return bdev->bd_disk->queue; /* this is never NULL */
820 * blk_rq_pos() : the current sector
821 * blk_rq_bytes() : bytes left in the entire request
822 * blk_rq_cur_bytes() : bytes left in the current segment
823 * blk_rq_err_bytes() : bytes left till the next error boundary
824 * blk_rq_sectors() : sectors left in the entire request
825 * blk_rq_cur_sectors() : sectors left in the current segment
827 static inline sector_t blk_rq_pos(const struct request *rq)
832 static inline unsigned int blk_rq_bytes(const struct request *rq)
834 return rq->__data_len;
837 static inline int blk_rq_cur_bytes(const struct request *rq)
839 return rq->bio ? bio_cur_bytes(rq->bio) : 0;
842 extern unsigned int blk_rq_err_bytes(const struct request *rq);
844 static inline unsigned int blk_rq_sectors(const struct request *rq)
846 return blk_rq_bytes(rq) >> 9;
849 static inline unsigned int blk_rq_cur_sectors(const struct request *rq)
851 return blk_rq_cur_bytes(rq) >> 9;
854 static inline unsigned int blk_queue_get_max_sectors(struct request_queue *q,
855 unsigned int cmd_flags)
857 if (unlikely(cmd_flags & REQ_DISCARD))
858 return min(q->limits.max_discard_sectors, UINT_MAX >> 9);
860 if (unlikely(cmd_flags & REQ_WRITE_SAME))
861 return q->limits.max_write_same_sectors;
863 return q->limits.max_sectors;
867 * Return maximum size of a request at given offset. Only valid for
868 * file system requests.
870 static inline unsigned int blk_max_size_offset(struct request_queue *q,
873 if (!q->limits.chunk_sectors)
874 return q->limits.max_sectors;
876 return q->limits.chunk_sectors -
877 (offset & (q->limits.chunk_sectors - 1));
880 static inline unsigned int blk_rq_get_max_sectors(struct request *rq)
882 struct request_queue *q = rq->q;
884 if (unlikely(rq->cmd_type == REQ_TYPE_BLOCK_PC))
885 return q->limits.max_hw_sectors;
887 if (!q->limits.chunk_sectors || (rq->cmd_flags & REQ_DISCARD))
888 return blk_queue_get_max_sectors(q, rq->cmd_flags);
890 return min(blk_max_size_offset(q, blk_rq_pos(rq)),
891 blk_queue_get_max_sectors(q, rq->cmd_flags));
894 static inline unsigned int blk_rq_count_bios(struct request *rq)
896 unsigned int nr_bios = 0;
899 __rq_for_each_bio(bio, rq)
906 * Request issue related functions.
908 extern struct request *blk_peek_request(struct request_queue *q);
909 extern void blk_start_request(struct request *rq);
910 extern struct request *blk_fetch_request(struct request_queue *q);
913 * Request completion related functions.
915 * blk_update_request() completes given number of bytes and updates
916 * the request without completing it.
918 * blk_end_request() and friends. __blk_end_request() must be called
919 * with the request queue spinlock acquired.
921 * Several drivers define their own end_request and call
922 * blk_end_request() for parts of the original function.
923 * This prevents code duplication in drivers.
925 extern bool blk_update_request(struct request *rq, int error,
926 unsigned int nr_bytes);
927 extern void blk_finish_request(struct request *rq, int error);
928 extern bool blk_end_request(struct request *rq, int error,
929 unsigned int nr_bytes);
930 extern void blk_end_request_all(struct request *rq, int error);
931 extern bool blk_end_request_cur(struct request *rq, int error);
932 extern bool blk_end_request_err(struct request *rq, int error);
933 extern bool __blk_end_request(struct request *rq, int error,
934 unsigned int nr_bytes);
935 extern void __blk_end_request_all(struct request *rq, int error);
936 extern bool __blk_end_request_cur(struct request *rq, int error);
937 extern bool __blk_end_request_err(struct request *rq, int error);
939 extern void blk_complete_request(struct request *);
940 extern void __blk_complete_request(struct request *);
941 extern void blk_abort_request(struct request *);
942 extern void blk_unprep_request(struct request *);
945 * Access functions for manipulating queue properties
947 extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
948 spinlock_t *lock, int node_id);
949 extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
950 extern struct request_queue *blk_init_allocated_queue(struct request_queue *,
951 request_fn_proc *, spinlock_t *);
952 extern void blk_cleanup_queue(struct request_queue *);
953 extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
954 extern void blk_queue_bounce_limit(struct request_queue *, u64);
955 extern void blk_limits_max_hw_sectors(struct queue_limits *, unsigned int);
956 extern void blk_queue_max_hw_sectors(struct request_queue *, unsigned int);
957 extern void blk_queue_chunk_sectors(struct request_queue *, unsigned int);
958 extern void blk_queue_max_segments(struct request_queue *, unsigned short);
959 extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
960 extern void blk_queue_max_discard_sectors(struct request_queue *q,
961 unsigned int max_discard_sectors);
962 extern void blk_queue_max_write_same_sectors(struct request_queue *q,
963 unsigned int max_write_same_sectors);
964 extern void blk_queue_logical_block_size(struct request_queue *, unsigned short);
965 extern void blk_queue_physical_block_size(struct request_queue *, unsigned int);
966 extern void blk_queue_alignment_offset(struct request_queue *q,
967 unsigned int alignment);
968 extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min);
969 extern void blk_queue_io_min(struct request_queue *q, unsigned int min);
970 extern void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt);
971 extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt);
972 extern void blk_set_default_limits(struct queue_limits *lim);
973 extern void blk_set_stacking_limits(struct queue_limits *lim);
974 extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
976 extern int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
978 extern void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
980 extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
981 extern void blk_queue_dma_pad(struct request_queue *, unsigned int);
982 extern void blk_queue_update_dma_pad(struct request_queue *, unsigned int);
983 extern int blk_queue_dma_drain(struct request_queue *q,
984 dma_drain_needed_fn *dma_drain_needed,
985 void *buf, unsigned int size);
986 extern void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn);
987 extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
988 extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
989 extern void blk_queue_unprep_rq(struct request_queue *, unprep_rq_fn *ufn);
990 extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
991 extern void blk_queue_dma_alignment(struct request_queue *, int);
992 extern void blk_queue_update_dma_alignment(struct request_queue *, int);
993 extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
994 extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *);
995 extern void blk_queue_rq_timeout(struct request_queue *, unsigned int);
996 extern void blk_queue_flush(struct request_queue *q, unsigned int flush);
997 extern void blk_queue_flush_queueable(struct request_queue *q, bool queueable);
998 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
1000 extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
1001 extern void blk_dump_rq_flags(struct request *, char *);
1002 extern long nr_blockdev_pages(void);
1004 bool __must_check blk_get_queue(struct request_queue *);
1005 struct request_queue *blk_alloc_queue(gfp_t);
1006 struct request_queue *blk_alloc_queue_node(gfp_t, int);
1007 extern void blk_put_queue(struct request_queue *);
1010 * block layer runtime pm functions
1013 extern void blk_pm_runtime_init(struct request_queue *q, struct device *dev);
1014 extern int blk_pre_runtime_suspend(struct request_queue *q);
1015 extern void blk_post_runtime_suspend(struct request_queue *q, int err);
1016 extern void blk_pre_runtime_resume(struct request_queue *q);
1017 extern void blk_post_runtime_resume(struct request_queue *q, int err);
1019 static inline void blk_pm_runtime_init(struct request_queue *q,
1020 struct device *dev) {}
1021 static inline int blk_pre_runtime_suspend(struct request_queue *q)
1025 static inline void blk_post_runtime_suspend(struct request_queue *q, int err) {}
1026 static inline void blk_pre_runtime_resume(struct request_queue *q) {}
1027 static inline void blk_post_runtime_resume(struct request_queue *q, int err) {}
1031 * blk_plug permits building a queue of related requests by holding the I/O
1032 * fragments for a short period. This allows merging of sequential requests
1033 * into single larger request. As the requests are moved from a per-task list to
1034 * the device's request_queue in a batch, this results in improved scalability
1035 * as the lock contention for request_queue lock is reduced.
1037 * It is ok not to disable preemption when adding the request to the plug list
1038 * or when attempting a merge, because blk_schedule_flush_list() will only flush
1039 * the plug list when the task sleeps by itself. For details, please see
1040 * schedule() where blk_schedule_flush_plug() is called.
1043 struct list_head list; /* requests */
1044 struct list_head mq_list; /* blk-mq requests */
1045 struct list_head cb_list; /* md requires an unplug callback */
1047 #define BLK_MAX_REQUEST_COUNT 16
1050 typedef void (*blk_plug_cb_fn)(struct blk_plug_cb *, bool);
1051 struct blk_plug_cb {
1052 struct list_head list;
1053 blk_plug_cb_fn callback;
1056 extern struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug,
1057 void *data, int size);
1058 extern void blk_start_plug(struct blk_plug *);
1059 extern void blk_finish_plug(struct blk_plug *);
1060 extern void blk_flush_plug_list(struct blk_plug *, bool);
1062 static inline void blk_flush_plug(struct task_struct *tsk)
1064 struct blk_plug *plug = tsk->plug;
1067 blk_flush_plug_list(plug, false);
1070 static inline void blk_schedule_flush_plug(struct task_struct *tsk)
1072 struct blk_plug *plug = tsk->plug;
1075 blk_flush_plug_list(plug, true);
1078 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
1080 struct blk_plug *plug = tsk->plug;
1083 (!list_empty(&plug->list) ||
1084 !list_empty(&plug->mq_list) ||
1085 !list_empty(&plug->cb_list));
1091 extern int blk_queue_start_tag(struct request_queue *, struct request *);
1092 extern struct request *blk_queue_find_tag(struct request_queue *, int);
1093 extern void blk_queue_end_tag(struct request_queue *, struct request *);
1094 extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *, int);
1095 extern void blk_queue_free_tags(struct request_queue *);
1096 extern int blk_queue_resize_tags(struct request_queue *, int);
1097 extern void blk_queue_invalidate_tags(struct request_queue *);
1098 extern struct blk_queue_tag *blk_init_tags(int, int);
1099 extern void blk_free_tags(struct blk_queue_tag *);
1101 static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
1104 if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
1106 return bqt->tag_index[tag];
1109 #define BLKDEV_DISCARD_SECURE 0x01 /* secure discard */
1111 extern int blkdev_issue_flush(struct block_device *, gfp_t, sector_t *);
1112 extern int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
1113 sector_t nr_sects, gfp_t gfp_mask, unsigned long flags);
1114 extern int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
1115 sector_t nr_sects, gfp_t gfp_mask, struct page *page);
1116 extern int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
1117 sector_t nr_sects, gfp_t gfp_mask, bool discard);
1118 static inline int sb_issue_discard(struct super_block *sb, sector_t block,
1119 sector_t nr_blocks, gfp_t gfp_mask, unsigned long flags)
1121 return blkdev_issue_discard(sb->s_bdev, block << (sb->s_blocksize_bits - 9),
1122 nr_blocks << (sb->s_blocksize_bits - 9),
1125 static inline int sb_issue_zeroout(struct super_block *sb, sector_t block,
1126 sector_t nr_blocks, gfp_t gfp_mask)
1128 return blkdev_issue_zeroout(sb->s_bdev,
1129 block << (sb->s_blocksize_bits - 9),
1130 nr_blocks << (sb->s_blocksize_bits - 9),
1134 extern int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm);
1136 enum blk_default_limits {
1137 BLK_MAX_SEGMENTS = 128,
1138 BLK_SAFE_MAX_SECTORS = 255,
1139 BLK_MAX_SEGMENT_SIZE = 65536,
1140 BLK_SEG_BOUNDARY_MASK = 0xFFFFFFFFUL,
1143 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
1145 static inline unsigned long queue_bounce_pfn(struct request_queue *q)
1147 return q->limits.bounce_pfn;
1150 static inline unsigned long queue_segment_boundary(struct request_queue *q)
1152 return q->limits.seg_boundary_mask;
1155 static inline unsigned int queue_max_sectors(struct request_queue *q)
1157 return q->limits.max_sectors;
1160 static inline unsigned int queue_max_hw_sectors(struct request_queue *q)
1162 return q->limits.max_hw_sectors;
1165 static inline unsigned short queue_max_segments(struct request_queue *q)
1167 return q->limits.max_segments;
1170 static inline unsigned int queue_max_segment_size(struct request_queue *q)
1172 return q->limits.max_segment_size;
1175 static inline unsigned short queue_logical_block_size(struct request_queue *q)
1179 if (q && q->limits.logical_block_size)
1180 retval = q->limits.logical_block_size;
1185 static inline unsigned short bdev_logical_block_size(struct block_device *bdev)
1187 return queue_logical_block_size(bdev_get_queue(bdev));
1190 static inline unsigned int queue_physical_block_size(struct request_queue *q)
1192 return q->limits.physical_block_size;
1195 static inline unsigned int bdev_physical_block_size(struct block_device *bdev)
1197 return queue_physical_block_size(bdev_get_queue(bdev));
1200 static inline unsigned int queue_io_min(struct request_queue *q)
1202 return q->limits.io_min;
1205 static inline int bdev_io_min(struct block_device *bdev)
1207 return queue_io_min(bdev_get_queue(bdev));
1210 static inline unsigned int queue_io_opt(struct request_queue *q)
1212 return q->limits.io_opt;
1215 static inline int bdev_io_opt(struct block_device *bdev)
1217 return queue_io_opt(bdev_get_queue(bdev));
1220 static inline int queue_alignment_offset(struct request_queue *q)
1222 if (q->limits.misaligned)
1225 return q->limits.alignment_offset;
1228 static inline int queue_limit_alignment_offset(struct queue_limits *lim, sector_t sector)
1230 unsigned int granularity = max(lim->physical_block_size, lim->io_min);
1231 unsigned int alignment = sector_div(sector, granularity >> 9) << 9;
1233 return (granularity + lim->alignment_offset - alignment) % granularity;
1236 static inline int bdev_alignment_offset(struct block_device *bdev)
1238 struct request_queue *q = bdev_get_queue(bdev);
1240 if (q->limits.misaligned)
1243 if (bdev != bdev->bd_contains)
1244 return bdev->bd_part->alignment_offset;
1246 return q->limits.alignment_offset;
1249 static inline int queue_discard_alignment(struct request_queue *q)
1251 if (q->limits.discard_misaligned)
1254 return q->limits.discard_alignment;
1257 static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector_t sector)
1259 unsigned int alignment, granularity, offset;
1261 if (!lim->max_discard_sectors)
1264 /* Why are these in bytes, not sectors? */
1265 alignment = lim->discard_alignment >> 9;
1266 granularity = lim->discard_granularity >> 9;
1270 /* Offset of the partition start in 'granularity' sectors */
1271 offset = sector_div(sector, granularity);
1273 /* And why do we do this modulus *again* in blkdev_issue_discard()? */
1274 offset = (granularity + alignment - offset) % granularity;
1276 /* Turn it back into bytes, gaah */
1280 static inline int bdev_discard_alignment(struct block_device *bdev)
1282 struct request_queue *q = bdev_get_queue(bdev);
1284 if (bdev != bdev->bd_contains)
1285 return bdev->bd_part->discard_alignment;
1287 return q->limits.discard_alignment;
1290 static inline unsigned int queue_discard_zeroes_data(struct request_queue *q)
1292 if (q->limits.max_discard_sectors && q->limits.discard_zeroes_data == 1)
1298 static inline unsigned int bdev_discard_zeroes_data(struct block_device *bdev)
1300 return queue_discard_zeroes_data(bdev_get_queue(bdev));
1303 static inline unsigned int bdev_write_same(struct block_device *bdev)
1305 struct request_queue *q = bdev_get_queue(bdev);
1308 return q->limits.max_write_same_sectors;
1313 static inline int queue_dma_alignment(struct request_queue *q)
1315 return q ? q->dma_alignment : 511;
1318 static inline int blk_rq_aligned(struct request_queue *q, unsigned long addr,
1321 unsigned int alignment = queue_dma_alignment(q) | q->dma_pad_mask;
1322 return !(addr & alignment) && !(len & alignment);
1325 /* assumes size > 256 */
1326 static inline unsigned int blksize_bits(unsigned int size)
1328 unsigned int bits = 8;
1332 } while (size > 256);
1336 static inline unsigned int block_size(struct block_device *bdev)
1338 return bdev->bd_block_size;
1341 static inline bool queue_flush_queueable(struct request_queue *q)
1343 return !q->flush_not_queueable;
1346 typedef struct {struct page *v;} Sector;
1348 unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
1350 static inline void put_dev_sector(Sector p)
1352 page_cache_release(p.v);
1356 int kblockd_schedule_work(struct work_struct *work);
1357 int kblockd_schedule_delayed_work(struct delayed_work *dwork, unsigned long delay);
1358 int kblockd_schedule_delayed_work_on(int cpu, struct delayed_work *dwork, unsigned long delay);
1360 #ifdef CONFIG_BLK_CGROUP
1362 * This should not be using sched_clock(). A real patch is in progress
1363 * to fix this up, until that is in place we need to disable preemption
1364 * around sched_clock() in this function and set_io_start_time_ns().
1366 static inline void set_start_time_ns(struct request *req)
1369 req->start_time_ns = sched_clock();
1373 static inline void set_io_start_time_ns(struct request *req)
1376 req->io_start_time_ns = sched_clock();
1380 static inline uint64_t rq_start_time_ns(struct request *req)
1382 return req->start_time_ns;
1385 static inline uint64_t rq_io_start_time_ns(struct request *req)
1387 return req->io_start_time_ns;
1390 static inline void set_start_time_ns(struct request *req) {}
1391 static inline void set_io_start_time_ns(struct request *req) {}
1392 static inline uint64_t rq_start_time_ns(struct request *req)
1396 static inline uint64_t rq_io_start_time_ns(struct request *req)
1402 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
1403 MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
1404 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
1405 MODULE_ALIAS("block-major-" __stringify(major) "-*")
1407 #if defined(CONFIG_BLK_DEV_INTEGRITY)
1409 enum blk_integrity_flags {
1410 BLK_INTEGRITY_VERIFY = 1 << 0,
1411 BLK_INTEGRITY_GENERATE = 1 << 1,
1412 BLK_INTEGRITY_DEVICE_CAPABLE = 1 << 2,
1413 BLK_INTEGRITY_IP_CHECKSUM = 1 << 3,
1416 struct blk_integrity_iter {
1420 unsigned int data_size;
1421 unsigned short interval;
1422 const char *disk_name;
1425 typedef int (integrity_processing_fn) (struct blk_integrity_iter *);
1427 struct blk_integrity {
1428 integrity_processing_fn *generate_fn;
1429 integrity_processing_fn *verify_fn;
1431 unsigned short flags;
1432 unsigned short tuple_size;
1433 unsigned short interval;
1434 unsigned short tag_size;
1438 struct kobject kobj;
1441 extern bool blk_integrity_is_initialized(struct gendisk *);
1442 extern int blk_integrity_register(struct gendisk *, struct blk_integrity *);
1443 extern void blk_integrity_unregister(struct gendisk *);
1444 extern int blk_integrity_compare(struct gendisk *, struct gendisk *);
1445 extern int blk_rq_map_integrity_sg(struct request_queue *, struct bio *,
1446 struct scatterlist *);
1447 extern int blk_rq_count_integrity_sg(struct request_queue *, struct bio *);
1448 extern bool blk_integrity_merge_rq(struct request_queue *, struct request *,
1450 extern bool blk_integrity_merge_bio(struct request_queue *, struct request *,
1454 struct blk_integrity *bdev_get_integrity(struct block_device *bdev)
1456 return bdev->bd_disk->integrity;
1459 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1461 return disk->integrity;
1464 static inline bool blk_integrity_rq(struct request *rq)
1466 return rq->cmd_flags & REQ_INTEGRITY;
1469 static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1472 q->limits.max_integrity_segments = segs;
1475 static inline unsigned short
1476 queue_max_integrity_segments(struct request_queue *q)
1478 return q->limits.max_integrity_segments;
1481 #else /* CONFIG_BLK_DEV_INTEGRITY */
1484 struct block_device;
1486 struct blk_integrity;
1488 static inline int blk_integrity_rq(struct request *rq)
1492 static inline int blk_rq_count_integrity_sg(struct request_queue *q,
1497 static inline int blk_rq_map_integrity_sg(struct request_queue *q,
1499 struct scatterlist *s)
1503 static inline struct blk_integrity *bdev_get_integrity(struct block_device *b)
1507 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
1511 static inline int blk_integrity_compare(struct gendisk *a, struct gendisk *b)
1515 static inline int blk_integrity_register(struct gendisk *d,
1516 struct blk_integrity *b)
1520 static inline void blk_integrity_unregister(struct gendisk *d)
1523 static inline void blk_queue_max_integrity_segments(struct request_queue *q,
1527 static inline unsigned short queue_max_integrity_segments(struct request_queue *q)
1531 static inline bool blk_integrity_merge_rq(struct request_queue *rq,
1537 static inline bool blk_integrity_merge_bio(struct request_queue *rq,
1543 static inline bool blk_integrity_is_initialized(struct gendisk *g)
1548 #endif /* CONFIG_BLK_DEV_INTEGRITY */
1550 struct block_device_operations {
1551 int (*open) (struct block_device *, fmode_t);
1552 void (*release) (struct gendisk *, fmode_t);
1553 int (*rw_page)(struct block_device *, sector_t, struct page *, int rw);
1554 int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1555 int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
1556 long (*direct_access)(struct block_device *, sector_t,
1557 void **, unsigned long *pfn, long size);
1558 unsigned int (*check_events) (struct gendisk *disk,
1559 unsigned int clearing);
1560 /* ->media_changed() is DEPRECATED, use ->check_events() instead */
1561 int (*media_changed) (struct gendisk *);
1562 void (*unlock_native_capacity) (struct gendisk *);
1563 int (*revalidate_disk) (struct gendisk *);
1564 int (*getgeo)(struct block_device *, struct hd_geometry *);
1565 /* this callback is with swap_lock and sometimes page table lock held */
1566 void (*swap_slot_free_notify) (struct block_device *, unsigned long);
1567 struct module *owner;
1570 extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int,
1572 extern int bdev_read_page(struct block_device *, sector_t, struct page *);
1573 extern int bdev_write_page(struct block_device *, sector_t, struct page *,
1574 struct writeback_control *);
1575 extern long bdev_direct_access(struct block_device *, sector_t, void **addr,
1576 unsigned long *pfn, long size);
1577 #else /* CONFIG_BLOCK */
1579 struct block_device;
1582 * stubs for when the block layer is configured out
1584 #define buffer_heads_over_limit 0
1586 static inline long nr_blockdev_pages(void)
1594 static inline void blk_start_plug(struct blk_plug *plug)
1598 static inline void blk_finish_plug(struct blk_plug *plug)
1602 static inline void blk_flush_plug(struct task_struct *task)
1606 static inline void blk_schedule_flush_plug(struct task_struct *task)
1611 static inline bool blk_needs_flush_plug(struct task_struct *tsk)
1616 static inline int blkdev_issue_flush(struct block_device *bdev, gfp_t gfp_mask,
1617 sector_t *error_sector)
1622 #endif /* CONFIG_BLOCK */