1 #ifndef _LINUX_BLKDEV_H
2 #define _LINUX_BLKDEV_H
6 #include <linux/sched.h>
7 #include <linux/major.h>
8 #include <linux/genhd.h>
9 #include <linux/list.h>
10 #include <linux/timer.h>
11 #include <linux/workqueue.h>
12 #include <linux/pagemap.h>
13 #include <linux/backing-dev.h>
14 #include <linux/wait.h>
15 #include <linux/mempool.h>
16 #include <linux/bio.h>
17 #include <linux/module.h>
18 #include <linux/stringify.h>
19 #include <linux/gfp.h>
20 #include <linux/bsg.h>
21 #include <linux/smp.h>
23 #include <asm/scatterlist.h>
25 struct scsi_ioctl_command
;
28 struct elevator_queue
;
29 struct request_pm_state
;
34 #define BLKDEV_MIN_RQ 4
35 #define BLKDEV_MAX_RQ 128 /* Default maximum */
38 typedef void (rq_end_io_fn
)(struct request
*, int);
42 * count[], starved[], and wait[] are indexed by
43 * BLK_RW_SYNC/BLK_RW_ASYNC
49 wait_queue_head_t wait
[2];
53 * request command types
55 enum rq_cmd_type_bits
{
56 REQ_TYPE_FS
= 1, /* fs request */
57 REQ_TYPE_BLOCK_PC
, /* scsi command */
58 REQ_TYPE_SENSE
, /* sense request */
59 REQ_TYPE_PM_SUSPEND
, /* suspend request */
60 REQ_TYPE_PM_RESUME
, /* resume request */
61 REQ_TYPE_PM_SHUTDOWN
, /* shutdown request */
62 REQ_TYPE_SPECIAL
, /* driver defined type */
63 REQ_TYPE_LINUX_BLOCK
, /* generic block layer message */
65 * for ATA/ATAPI devices. this really doesn't belong here, ide should
66 * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver
67 * private REQ_LB opcodes to differentiate what type of request this is
69 REQ_TYPE_ATA_TASKFILE
,
74 * For request of type REQ_TYPE_LINUX_BLOCK, rq->cmd[0] is the opcode being
75 * sent down (similar to how REQ_TYPE_BLOCK_PC means that ->cmd[] holds a
78 * 0x00 -> 0x3f are driver private, to be used for whatever purpose they need,
79 * typically to differentiate REQ_TYPE_SPECIAL requests.
83 REQ_LB_OP_EJECT
= 0x40, /* eject request */
84 REQ_LB_OP_FLUSH
= 0x41, /* flush request */
88 * request type modified bits. first four bits match BIO_RW* bits, important
91 __REQ_RW
, /* not set, read. set, write */
92 __REQ_FAILFAST_DEV
, /* no driver retries of device errors */
93 __REQ_FAILFAST_TRANSPORT
, /* no driver retries of transport errors */
94 __REQ_FAILFAST_DRIVER
, /* no driver retries of driver errors */
95 /* above flags must match BIO_RW_* */
96 __REQ_DISCARD
, /* request to discard sectors */
97 __REQ_SORTED
, /* elevator knows about this request */
98 __REQ_SOFTBARRIER
, /* may not be passed by ioscheduler */
99 __REQ_HARDBARRIER
, /* may not be passed by drive either */
100 __REQ_FUA
, /* forced unit access */
101 __REQ_NOMERGE
, /* don't touch this for merging */
102 __REQ_STARTED
, /* drive already may have started this one */
103 __REQ_DONTPREP
, /* don't call prep for this one */
104 __REQ_QUEUED
, /* uses queueing */
105 __REQ_ELVPRIV
, /* elevator private data attached */
106 __REQ_FAILED
, /* set if the request failed */
107 __REQ_QUIET
, /* don't worry about errors */
108 __REQ_PREEMPT
, /* set for "ide_preempt" requests */
109 __REQ_ORDERED_COLOR
, /* is before or after barrier */
110 __REQ_RW_SYNC
, /* request is sync (sync write or read) */
111 __REQ_ALLOCED
, /* request came from our alloc pool */
112 __REQ_RW_META
, /* metadata io request */
113 __REQ_COPY_USER
, /* contains copies of user pages */
114 __REQ_INTEGRITY
, /* integrity metadata has been remapped */
115 __REQ_NOIDLE
, /* Don't anticipate more IO after this one */
116 __REQ_IO_STAT
, /* account I/O stat */
117 __REQ_MIXED_MERGE
, /* merge of different types, fail separately */
118 __REQ_NR_BITS
, /* stops here */
121 #define REQ_RW (1 << __REQ_RW)
122 #define REQ_FAILFAST_DEV (1 << __REQ_FAILFAST_DEV)
123 #define REQ_FAILFAST_TRANSPORT (1 << __REQ_FAILFAST_TRANSPORT)
124 #define REQ_FAILFAST_DRIVER (1 << __REQ_FAILFAST_DRIVER)
125 #define REQ_DISCARD (1 << __REQ_DISCARD)
126 #define REQ_SORTED (1 << __REQ_SORTED)
127 #define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER)
128 #define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER)
129 #define REQ_FUA (1 << __REQ_FUA)
130 #define REQ_NOMERGE (1 << __REQ_NOMERGE)
131 #define REQ_STARTED (1 << __REQ_STARTED)
132 #define REQ_DONTPREP (1 << __REQ_DONTPREP)
133 #define REQ_QUEUED (1 << __REQ_QUEUED)
134 #define REQ_ELVPRIV (1 << __REQ_ELVPRIV)
135 #define REQ_FAILED (1 << __REQ_FAILED)
136 #define REQ_QUIET (1 << __REQ_QUIET)
137 #define REQ_PREEMPT (1 << __REQ_PREEMPT)
138 #define REQ_ORDERED_COLOR (1 << __REQ_ORDERED_COLOR)
139 #define REQ_RW_SYNC (1 << __REQ_RW_SYNC)
140 #define REQ_ALLOCED (1 << __REQ_ALLOCED)
141 #define REQ_RW_META (1 << __REQ_RW_META)
142 #define REQ_COPY_USER (1 << __REQ_COPY_USER)
143 #define REQ_INTEGRITY (1 << __REQ_INTEGRITY)
144 #define REQ_NOIDLE (1 << __REQ_NOIDLE)
145 #define REQ_IO_STAT (1 << __REQ_IO_STAT)
146 #define REQ_MIXED_MERGE (1 << __REQ_MIXED_MERGE)
148 #define REQ_FAILFAST_MASK (REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | \
151 #define BLK_MAX_CDB 16
154 * try to put the fields that are referenced together in the same cacheline.
155 * if you modify this structure, be sure to check block/blk-core.c:rq_init()
159 struct list_head queuelist
;
160 struct call_single_data csd
;
163 struct request_queue
*q
;
165 unsigned int cmd_flags
;
166 enum rq_cmd_type_bits cmd_type
;
167 unsigned long atomic_flags
;
169 /* the following two fields are internal, NEVER access directly */
170 sector_t __sector
; /* sector cursor */
171 unsigned int __data_len
; /* total data len */
176 struct hlist_node hash
; /* merge hash */
178 * The rb_node is only used inside the io scheduler, requests
179 * are pruned when moved to the dispatch queue. So let the
180 * completion_data share space with the rb_node.
183 struct rb_node rb_node
; /* sort/lookup */
184 void *completion_data
;
188 * two pointers are available for the IO schedulers, if they need
189 * more they have to dynamically allocate it.
191 void *elevator_private
;
192 void *elevator_private2
;
194 struct gendisk
*rq_disk
;
195 unsigned long start_time
;
197 /* Number of scatter-gather DMA addr+len pairs after
198 * physical address coalescing is performed.
200 unsigned short nr_phys_segments
;
202 unsigned short ioprio
;
204 void *special
; /* opaque pointer available for LLD use */
205 char *buffer
; /* kaddr of the current segment if available */
213 * when request is used as a packet command carrier
215 unsigned short cmd_len
;
216 unsigned char __cmd
[BLK_MAX_CDB
];
219 unsigned int extra_len
; /* length of alignment and padding */
220 unsigned int sense_len
;
221 unsigned int resid_len
; /* residual count */
224 unsigned long deadline
;
225 struct list_head timeout_list
;
226 unsigned int timeout
;
230 * completion callback.
232 rq_end_io_fn
*end_io
;
236 struct request
*next_rq
;
239 static inline unsigned short req_get_ioprio(struct request
*req
)
245 * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
246 * requests. Some step values could eventually be made generic.
248 struct request_pm_state
250 /* PM state machine step value, currently driver specific */
252 /* requested PM state value (S1, S2, S3, S4, ...) */
254 void* data
; /* for driver use */
257 #include <linux/elevator.h>
259 typedef void (request_fn_proc
) (struct request_queue
*q
);
260 typedef int (make_request_fn
) (struct request_queue
*q
, struct bio
*bio
);
261 typedef int (prep_rq_fn
) (struct request_queue
*, struct request
*);
262 typedef void (unplug_fn
) (struct request_queue
*);
265 struct bvec_merge_data
{
266 struct block_device
*bi_bdev
;
271 typedef int (merge_bvec_fn
) (struct request_queue
*, struct bvec_merge_data
*,
273 typedef void (prepare_flush_fn
) (struct request_queue
*, struct request
*);
274 typedef void (softirq_done_fn
)(struct request
*);
275 typedef int (dma_drain_needed_fn
)(struct request
*);
276 typedef int (lld_busy_fn
) (struct request_queue
*q
);
278 enum blk_eh_timer_return
{
284 typedef enum blk_eh_timer_return (rq_timed_out_fn
)(struct request
*);
286 enum blk_queue_state
{
291 struct blk_queue_tag
{
292 struct request
**tag_index
; /* map of busy tags */
293 unsigned long *tag_map
; /* bit map of free/busy tags */
294 int busy
; /* current depth */
295 int max_depth
; /* what we will send to device */
296 int real_max_depth
; /* what the array can hold */
297 atomic_t refcnt
; /* map can be shared */
300 #define BLK_SCSI_MAX_CMDS (256)
301 #define BLK_SCSI_CMD_PER_LONG (BLK_SCSI_MAX_CMDS / (sizeof(long) * 8))
303 struct queue_limits
{
304 unsigned long bounce_pfn
;
305 unsigned long seg_boundary_mask
;
307 unsigned int max_hw_sectors
;
308 unsigned int max_sectors
;
309 unsigned int max_segment_size
;
310 unsigned int physical_block_size
;
311 unsigned int alignment_offset
;
314 unsigned int max_discard_sectors
;
315 unsigned int discard_granularity
;
316 unsigned int discard_alignment
;
318 unsigned short logical_block_size
;
319 unsigned short max_hw_segments
;
320 unsigned short max_phys_segments
;
322 unsigned char misaligned
;
323 unsigned char discard_misaligned
;
324 unsigned char no_cluster
;
330 * Together with queue_head for cacheline sharing
332 struct list_head queue_head
;
333 struct request
*last_merge
;
334 struct elevator_queue
*elevator
;
337 * the queue request freelist, one for reads and one for writes
339 struct request_list rq
;
341 request_fn_proc
*request_fn
;
342 make_request_fn
*make_request_fn
;
343 prep_rq_fn
*prep_rq_fn
;
344 unplug_fn
*unplug_fn
;
345 merge_bvec_fn
*merge_bvec_fn
;
346 prepare_flush_fn
*prepare_flush_fn
;
347 softirq_done_fn
*softirq_done_fn
;
348 rq_timed_out_fn
*rq_timed_out_fn
;
349 dma_drain_needed_fn
*dma_drain_needed
;
350 lld_busy_fn
*lld_busy_fn
;
353 * Dispatch queue sorting
356 struct request
*boundary_rq
;
359 * Auto-unplugging state
361 struct timer_list unplug_timer
;
362 int unplug_thresh
; /* After this many requests */
363 unsigned long unplug_delay
; /* After this many jiffies */
364 struct work_struct unplug_work
;
366 struct backing_dev_info backing_dev_info
;
369 * The queue owner gets to use this for whatever they like.
370 * ll_rw_blk doesn't touch it.
375 * queue needs bounce pages for pages above this limit
380 * various queue flags, see QUEUE_* below
382 unsigned long queue_flags
;
385 * protects queue structures from reentrancy. ->__queue_lock should
386 * _never_ be used directly, it is queue private. always use
389 spinlock_t __queue_lock
;
390 spinlock_t
*queue_lock
;
400 unsigned long nr_requests
; /* Max # of requests */
401 unsigned int nr_congestion_on
;
402 unsigned int nr_congestion_off
;
403 unsigned int nr_batching
;
405 void *dma_drain_buffer
;
406 unsigned int dma_drain_size
;
407 unsigned int dma_pad_mask
;
408 unsigned int dma_alignment
;
410 struct blk_queue_tag
*queue_tags
;
411 struct list_head tag_busy_list
;
413 unsigned int nr_sorted
;
414 unsigned int in_flight
[2];
416 unsigned int rq_timeout
;
417 struct timer_list timeout
;
418 struct list_head timeout_list
;
420 struct queue_limits limits
;
425 unsigned int sg_timeout
;
426 unsigned int sg_reserved_size
;
428 #ifdef CONFIG_BLK_DEV_IO_TRACE
429 struct blk_trace
*blk_trace
;
432 * reserved for flush operations
434 unsigned int ordered
, next_ordered
, ordseq
;
435 int orderr
, ordcolor
;
436 struct request pre_flush_rq
, bar_rq
, post_flush_rq
;
437 struct request
*orig_bar_rq
;
439 struct mutex sysfs_lock
;
441 #if defined(CONFIG_BLK_DEV_BSG)
442 struct bsg_class_device bsg_dev
;
446 #define QUEUE_FLAG_CLUSTER 0 /* cluster several segments into 1 */
447 #define QUEUE_FLAG_QUEUED 1 /* uses generic tag queueing */
448 #define QUEUE_FLAG_STOPPED 2 /* queue is stopped */
449 #define QUEUE_FLAG_SYNCFULL 3 /* read queue has been filled */
450 #define QUEUE_FLAG_ASYNCFULL 4 /* write queue has been filled */
451 #define QUEUE_FLAG_DEAD 5 /* queue being torn down */
452 #define QUEUE_FLAG_REENTER 6 /* Re-entrancy avoidance */
453 #define QUEUE_FLAG_PLUGGED 7 /* queue is plugged */
454 #define QUEUE_FLAG_ELVSWITCH 8 /* don't use elevator, just do FIFO */
455 #define QUEUE_FLAG_BIDI 9 /* queue supports bidi requests */
456 #define QUEUE_FLAG_NOMERGES 10 /* disable merge attempts */
457 #define QUEUE_FLAG_SAME_COMP 11 /* force complete on same CPU */
458 #define QUEUE_FLAG_FAIL_IO 12 /* fake timeout */
459 #define QUEUE_FLAG_STACKABLE 13 /* supports request stacking */
460 #define QUEUE_FLAG_NONROT 14 /* non-rotational device (SSD) */
461 #define QUEUE_FLAG_VIRT QUEUE_FLAG_NONROT /* paravirt device */
462 #define QUEUE_FLAG_IO_STAT 15 /* do IO stats */
463 #define QUEUE_FLAG_CQ 16 /* hardware does queuing */
464 #define QUEUE_FLAG_DISCARD 17 /* supports DISCARD */
466 #define QUEUE_FLAG_DEFAULT ((1 << QUEUE_FLAG_IO_STAT) | \
467 (1 << QUEUE_FLAG_CLUSTER) | \
468 (1 << QUEUE_FLAG_STACKABLE) | \
469 (1 << QUEUE_FLAG_SAME_COMP))
471 static inline int queue_is_locked(struct request_queue
*q
)
474 spinlock_t
*lock
= q
->queue_lock
;
475 return lock
&& spin_is_locked(lock
);
481 static inline void queue_flag_set_unlocked(unsigned int flag
,
482 struct request_queue
*q
)
484 __set_bit(flag
, &q
->queue_flags
);
487 static inline int queue_flag_test_and_clear(unsigned int flag
,
488 struct request_queue
*q
)
490 WARN_ON_ONCE(!queue_is_locked(q
));
492 if (test_bit(flag
, &q
->queue_flags
)) {
493 __clear_bit(flag
, &q
->queue_flags
);
500 static inline int queue_flag_test_and_set(unsigned int flag
,
501 struct request_queue
*q
)
503 WARN_ON_ONCE(!queue_is_locked(q
));
505 if (!test_bit(flag
, &q
->queue_flags
)) {
506 __set_bit(flag
, &q
->queue_flags
);
513 static inline void queue_flag_set(unsigned int flag
, struct request_queue
*q
)
515 WARN_ON_ONCE(!queue_is_locked(q
));
516 __set_bit(flag
, &q
->queue_flags
);
519 static inline void queue_flag_clear_unlocked(unsigned int flag
,
520 struct request_queue
*q
)
522 __clear_bit(flag
, &q
->queue_flags
);
525 static inline int queue_in_flight(struct request_queue
*q
)
527 return q
->in_flight
[0] + q
->in_flight
[1];
530 static inline void queue_flag_clear(unsigned int flag
, struct request_queue
*q
)
532 WARN_ON_ONCE(!queue_is_locked(q
));
533 __clear_bit(flag
, &q
->queue_flags
);
538 * Hardbarrier is supported with one of the following methods.
540 * NONE : hardbarrier unsupported
541 * DRAIN : ordering by draining is enough
542 * DRAIN_FLUSH : ordering by draining w/ pre and post flushes
543 * DRAIN_FUA : ordering by draining w/ pre flush and FUA write
544 * TAG : ordering by tag is enough
545 * TAG_FLUSH : ordering by tag w/ pre and post flushes
546 * TAG_FUA : ordering by tag w/ pre flush and FUA write
548 QUEUE_ORDERED_BY_DRAIN
= 0x01,
549 QUEUE_ORDERED_BY_TAG
= 0x02,
550 QUEUE_ORDERED_DO_PREFLUSH
= 0x10,
551 QUEUE_ORDERED_DO_BAR
= 0x20,
552 QUEUE_ORDERED_DO_POSTFLUSH
= 0x40,
553 QUEUE_ORDERED_DO_FUA
= 0x80,
555 QUEUE_ORDERED_NONE
= 0x00,
557 QUEUE_ORDERED_DRAIN
= QUEUE_ORDERED_BY_DRAIN
|
558 QUEUE_ORDERED_DO_BAR
,
559 QUEUE_ORDERED_DRAIN_FLUSH
= QUEUE_ORDERED_DRAIN
|
560 QUEUE_ORDERED_DO_PREFLUSH
|
561 QUEUE_ORDERED_DO_POSTFLUSH
,
562 QUEUE_ORDERED_DRAIN_FUA
= QUEUE_ORDERED_DRAIN
|
563 QUEUE_ORDERED_DO_PREFLUSH
|
564 QUEUE_ORDERED_DO_FUA
,
566 QUEUE_ORDERED_TAG
= QUEUE_ORDERED_BY_TAG
|
567 QUEUE_ORDERED_DO_BAR
,
568 QUEUE_ORDERED_TAG_FLUSH
= QUEUE_ORDERED_TAG
|
569 QUEUE_ORDERED_DO_PREFLUSH
|
570 QUEUE_ORDERED_DO_POSTFLUSH
,
571 QUEUE_ORDERED_TAG_FUA
= QUEUE_ORDERED_TAG
|
572 QUEUE_ORDERED_DO_PREFLUSH
|
573 QUEUE_ORDERED_DO_FUA
,
576 * Ordered operation sequence
578 QUEUE_ORDSEQ_STARTED
= 0x01, /* flushing in progress */
579 QUEUE_ORDSEQ_DRAIN
= 0x02, /* waiting for the queue to be drained */
580 QUEUE_ORDSEQ_PREFLUSH
= 0x04, /* pre-flushing in progress */
581 QUEUE_ORDSEQ_BAR
= 0x08, /* original barrier req in progress */
582 QUEUE_ORDSEQ_POSTFLUSH
= 0x10, /* post-flushing in progress */
583 QUEUE_ORDSEQ_DONE
= 0x20,
586 #define blk_queue_plugged(q) test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
587 #define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
588 #define blk_queue_queuing(q) test_bit(QUEUE_FLAG_CQ, &(q)->queue_flags)
589 #define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
590 #define blk_queue_nomerges(q) test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
591 #define blk_queue_nonrot(q) test_bit(QUEUE_FLAG_NONROT, &(q)->queue_flags)
592 #define blk_queue_io_stat(q) test_bit(QUEUE_FLAG_IO_STAT, &(q)->queue_flags)
593 #define blk_queue_flushing(q) ((q)->ordseq)
594 #define blk_queue_stackable(q) \
595 test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags)
596 #define blk_queue_discard(q) test_bit(QUEUE_FLAG_DISCARD, &(q)->queue_flags)
598 #define blk_fs_request(rq) ((rq)->cmd_type == REQ_TYPE_FS)
599 #define blk_pc_request(rq) ((rq)->cmd_type == REQ_TYPE_BLOCK_PC)
600 #define blk_special_request(rq) ((rq)->cmd_type == REQ_TYPE_SPECIAL)
601 #define blk_sense_request(rq) ((rq)->cmd_type == REQ_TYPE_SENSE)
603 #define blk_failfast_dev(rq) ((rq)->cmd_flags & REQ_FAILFAST_DEV)
604 #define blk_failfast_transport(rq) ((rq)->cmd_flags & REQ_FAILFAST_TRANSPORT)
605 #define blk_failfast_driver(rq) ((rq)->cmd_flags & REQ_FAILFAST_DRIVER)
606 #define blk_noretry_request(rq) (blk_failfast_dev(rq) || \
607 blk_failfast_transport(rq) || \
608 blk_failfast_driver(rq))
609 #define blk_rq_started(rq) ((rq)->cmd_flags & REQ_STARTED)
610 #define blk_rq_io_stat(rq) ((rq)->cmd_flags & REQ_IO_STAT)
611 #define blk_rq_quiet(rq) ((rq)->cmd_flags & REQ_QUIET)
613 #define blk_account_rq(rq) (blk_rq_started(rq) && (blk_fs_request(rq) || blk_discard_rq(rq)))
615 #define blk_pm_suspend_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND)
616 #define blk_pm_resume_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_RESUME)
617 #define blk_pm_request(rq) \
618 (blk_pm_suspend_request(rq) || blk_pm_resume_request(rq))
620 #define blk_rq_cpu_valid(rq) ((rq)->cpu != -1)
621 #define blk_sorted_rq(rq) ((rq)->cmd_flags & REQ_SORTED)
622 #define blk_barrier_rq(rq) ((rq)->cmd_flags & REQ_HARDBARRIER)
623 #define blk_fua_rq(rq) ((rq)->cmd_flags & REQ_FUA)
624 #define blk_discard_rq(rq) ((rq)->cmd_flags & REQ_DISCARD)
625 #define blk_bidi_rq(rq) ((rq)->next_rq != NULL)
626 /* rq->queuelist of dequeued request must be list_empty() */
627 #define blk_queued_rq(rq) (!list_empty(&(rq)->queuelist))
629 #define list_entry_rq(ptr) list_entry((ptr), struct request, queuelist)
631 #define rq_data_dir(rq) ((rq)->cmd_flags & 1)
634 * We regard a request as sync, if either a read or a sync write
636 static inline bool rw_is_sync(unsigned int rw_flags
)
638 return !(rw_flags
& REQ_RW
) || (rw_flags
& REQ_RW_SYNC
);
641 static inline bool rq_is_sync(struct request
*rq
)
643 return rw_is_sync(rq
->cmd_flags
);
646 #define rq_is_meta(rq) ((rq)->cmd_flags & REQ_RW_META)
647 #define rq_noidle(rq) ((rq)->cmd_flags & REQ_NOIDLE)
649 static inline int blk_queue_full(struct request_queue
*q
, int sync
)
652 return test_bit(QUEUE_FLAG_SYNCFULL
, &q
->queue_flags
);
653 return test_bit(QUEUE_FLAG_ASYNCFULL
, &q
->queue_flags
);
656 static inline void blk_set_queue_full(struct request_queue
*q
, int sync
)
659 queue_flag_set(QUEUE_FLAG_SYNCFULL
, q
);
661 queue_flag_set(QUEUE_FLAG_ASYNCFULL
, q
);
664 static inline void blk_clear_queue_full(struct request_queue
*q
, int sync
)
667 queue_flag_clear(QUEUE_FLAG_SYNCFULL
, q
);
669 queue_flag_clear(QUEUE_FLAG_ASYNCFULL
, q
);
674 * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
675 * it already be started by driver.
677 #define RQ_NOMERGE_FLAGS \
678 (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER)
679 #define rq_mergeable(rq) \
680 (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && \
681 (blk_discard_rq(rq) || blk_fs_request((rq))))
684 * q->prep_rq_fn return values
686 #define BLKPREP_OK 0 /* serve it */
687 #define BLKPREP_KILL 1 /* fatal error, kill */
688 #define BLKPREP_DEFER 2 /* leave on queue */
690 extern unsigned long blk_max_low_pfn
, blk_max_pfn
;
693 * standard bounce addresses:
695 * BLK_BOUNCE_HIGH : bounce all highmem pages
696 * BLK_BOUNCE_ANY : don't bounce anything
697 * BLK_BOUNCE_ISA : bounce pages above ISA DMA boundary
700 #if BITS_PER_LONG == 32
701 #define BLK_BOUNCE_HIGH ((u64)blk_max_low_pfn << PAGE_SHIFT)
703 #define BLK_BOUNCE_HIGH -1ULL
705 #define BLK_BOUNCE_ANY (-1ULL)
706 #define BLK_BOUNCE_ISA (ISA_DMA_THRESHOLD)
709 * default timeout for SG_IO if none specified
711 #define BLK_DEFAULT_SG_TIMEOUT (60 * HZ)
712 #define BLK_MIN_SG_TIMEOUT (7 * HZ)
715 extern int init_emergency_isa_pool(void);
716 extern void blk_queue_bounce(struct request_queue
*q
, struct bio
**bio
);
718 static inline int init_emergency_isa_pool(void)
722 static inline void blk_queue_bounce(struct request_queue
*q
, struct bio
**bio
)
725 #endif /* CONFIG_MMU */
731 unsigned long offset
;
736 struct req_iterator
{
741 /* This should not be used directly - use rq_for_each_segment */
742 #define for_each_bio(_bio) \
743 for (; _bio; _bio = _bio->bi_next)
744 #define __rq_for_each_bio(_bio, rq) \
746 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
748 #define rq_for_each_segment(bvl, _rq, _iter) \
749 __rq_for_each_bio(_iter.bio, _rq) \
750 bio_for_each_segment(bvl, _iter.bio, _iter.i)
752 #define rq_iter_last(rq, _iter) \
753 (_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)
755 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
756 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
758 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
759 extern void rq_flush_dcache_pages(struct request
*rq
);
761 static inline void rq_flush_dcache_pages(struct request
*rq
)
766 extern int blk_register_queue(struct gendisk
*disk
);
767 extern void blk_unregister_queue(struct gendisk
*disk
);
768 extern void register_disk(struct gendisk
*dev
);
769 extern void generic_make_request(struct bio
*bio
);
770 extern void blk_rq_init(struct request_queue
*q
, struct request
*rq
);
771 extern void blk_put_request(struct request
*);
772 extern void __blk_put_request(struct request_queue
*, struct request
*);
773 extern struct request
*blk_get_request(struct request_queue
*, int, gfp_t
);
774 extern struct request
*blk_make_request(struct request_queue
*, struct bio
*,
776 extern void blk_insert_request(struct request_queue
*, struct request
*, int, void *);
777 extern void blk_requeue_request(struct request_queue
*, struct request
*);
778 extern int blk_rq_check_limits(struct request_queue
*q
, struct request
*rq
);
779 extern int blk_lld_busy(struct request_queue
*q
);
780 extern int blk_rq_prep_clone(struct request
*rq
, struct request
*rq_src
,
781 struct bio_set
*bs
, gfp_t gfp_mask
,
782 int (*bio_ctr
)(struct bio
*, struct bio
*, void *),
784 extern void blk_rq_unprep_clone(struct request
*rq
);
785 extern int blk_insert_cloned_request(struct request_queue
*q
,
787 extern void blk_plug_device(struct request_queue
*);
788 extern void blk_plug_device_unlocked(struct request_queue
*);
789 extern int blk_remove_plug(struct request_queue
*);
790 extern void blk_recount_segments(struct request_queue
*, struct bio
*);
791 extern int scsi_cmd_ioctl(struct request_queue
*, struct gendisk
*, fmode_t
,
792 unsigned int, void __user
*);
793 extern int sg_scsi_ioctl(struct request_queue
*, struct gendisk
*, fmode_t
,
794 struct scsi_ioctl_command __user
*);
797 * A queue has just exitted congestion. Note this in the global counter of
798 * congested queues, and wake up anyone who was waiting for requests to be
801 static inline void blk_clear_queue_congested(struct request_queue
*q
, int sync
)
803 clear_bdi_congested(&q
->backing_dev_info
, sync
);
807 * A queue has just entered congestion. Flag that in the queue's VM-visible
808 * state flags and increment the global gounter of congested queues.
810 static inline void blk_set_queue_congested(struct request_queue
*q
, int sync
)
812 set_bdi_congested(&q
->backing_dev_info
, sync
);
815 extern void blk_start_queue(struct request_queue
*q
);
816 extern void blk_stop_queue(struct request_queue
*q
);
817 extern void blk_sync_queue(struct request_queue
*q
);
818 extern void __blk_stop_queue(struct request_queue
*q
);
819 extern void __blk_run_queue(struct request_queue
*);
820 extern void blk_run_queue(struct request_queue
*);
821 extern int blk_rq_map_user(struct request_queue
*, struct request
*,
822 struct rq_map_data
*, void __user
*, unsigned long,
824 extern int blk_rq_unmap_user(struct bio
*);
825 extern int blk_rq_map_kern(struct request_queue
*, struct request
*, void *, unsigned int, gfp_t
);
826 extern int blk_rq_map_user_iov(struct request_queue
*, struct request
*,
827 struct rq_map_data
*, struct sg_iovec
*, int,
828 unsigned int, gfp_t
);
829 extern int blk_execute_rq(struct request_queue
*, struct gendisk
*,
830 struct request
*, int);
831 extern void blk_execute_rq_nowait(struct request_queue
*, struct gendisk
*,
832 struct request
*, int, rq_end_io_fn
*);
833 extern void blk_unplug(struct request_queue
*q
);
835 static inline struct request_queue
*bdev_get_queue(struct block_device
*bdev
)
837 return bdev
->bd_disk
->queue
;
841 * blk_rq_pos() : the current sector
842 * blk_rq_bytes() : bytes left in the entire request
843 * blk_rq_cur_bytes() : bytes left in the current segment
844 * blk_rq_err_bytes() : bytes left till the next error boundary
845 * blk_rq_sectors() : sectors left in the entire request
846 * blk_rq_cur_sectors() : sectors left in the current segment
847 * blk_rq_err_sectors() : sectors left till the next error boundary
849 static inline sector_t
blk_rq_pos(const struct request
*rq
)
854 static inline unsigned int blk_rq_bytes(const struct request
*rq
)
856 return rq
->__data_len
;
859 static inline int blk_rq_cur_bytes(const struct request
*rq
)
861 return rq
->bio
? bio_cur_bytes(rq
->bio
) : 0;
864 extern unsigned int blk_rq_err_bytes(const struct request
*rq
);
866 static inline unsigned int blk_rq_sectors(const struct request
*rq
)
868 return blk_rq_bytes(rq
) >> 9;
871 static inline unsigned int blk_rq_cur_sectors(const struct request
*rq
)
873 return blk_rq_cur_bytes(rq
) >> 9;
876 static inline unsigned int blk_rq_err_sectors(const struct request
*rq
)
878 return blk_rq_err_bytes(rq
) >> 9;
882 * Request issue related functions.
884 extern struct request
*blk_peek_request(struct request_queue
*q
);
885 extern void blk_start_request(struct request
*rq
);
886 extern struct request
*blk_fetch_request(struct request_queue
*q
);
889 * Request completion related functions.
891 * blk_update_request() completes given number of bytes and updates
892 * the request without completing it.
894 * blk_end_request() and friends. __blk_end_request() must be called
895 * with the request queue spinlock acquired.
897 * Several drivers define their own end_request and call
898 * blk_end_request() for parts of the original function.
899 * This prevents code duplication in drivers.
901 extern bool blk_update_request(struct request
*rq
, int error
,
902 unsigned int nr_bytes
);
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
);
908 extern bool __blk_end_request(struct request
*rq
, int error
,
909 unsigned int nr_bytes
);
910 extern void __blk_end_request_all(struct request
*rq
, int error
);
911 extern bool __blk_end_request_cur(struct request
*rq
, int error
);
912 extern bool __blk_end_request_err(struct request
*rq
, int error
);
914 extern void blk_complete_request(struct request
*);
915 extern void __blk_complete_request(struct request
*);
916 extern void blk_abort_request(struct request
*);
917 extern void blk_abort_queue(struct request_queue
*);
920 * Access functions for manipulating queue properties
922 extern struct request_queue
*blk_init_queue_node(request_fn_proc
*rfn
,
923 spinlock_t
*lock
, int node_id
);
924 extern struct request_queue
*blk_init_queue(request_fn_proc
*, spinlock_t
*);
925 extern void blk_cleanup_queue(struct request_queue
*);
926 extern void blk_queue_make_request(struct request_queue
*, make_request_fn
*);
927 extern void blk_queue_bounce_limit(struct request_queue
*, u64
);
928 extern void blk_queue_max_sectors(struct request_queue
*, unsigned int);
929 extern void blk_queue_max_hw_sectors(struct request_queue
*, unsigned int);
930 extern void blk_queue_max_phys_segments(struct request_queue
*, unsigned short);
931 extern void blk_queue_max_hw_segments(struct request_queue
*, unsigned short);
932 extern void blk_queue_max_segment_size(struct request_queue
*, unsigned int);
933 extern void blk_queue_max_discard_sectors(struct request_queue
*q
,
934 unsigned int max_discard_sectors
);
935 extern void blk_queue_logical_block_size(struct request_queue
*, unsigned short);
936 extern void blk_queue_physical_block_size(struct request_queue
*, unsigned short);
937 extern void blk_queue_alignment_offset(struct request_queue
*q
,
938 unsigned int alignment
);
939 extern void blk_limits_io_min(struct queue_limits
*limits
, unsigned int min
);
940 extern void blk_queue_io_min(struct request_queue
*q
, unsigned int min
);
941 extern void blk_limits_io_opt(struct queue_limits
*limits
, unsigned int opt
);
942 extern void blk_queue_io_opt(struct request_queue
*q
, unsigned int opt
);
943 extern void blk_set_default_limits(struct queue_limits
*lim
);
944 extern int blk_stack_limits(struct queue_limits
*t
, struct queue_limits
*b
,
946 extern void disk_stack_limits(struct gendisk
*disk
, struct block_device
*bdev
,
948 extern void blk_queue_stack_limits(struct request_queue
*t
, struct request_queue
*b
);
949 extern void blk_queue_dma_pad(struct request_queue
*, unsigned int);
950 extern void blk_queue_update_dma_pad(struct request_queue
*, unsigned int);
951 extern int blk_queue_dma_drain(struct request_queue
*q
,
952 dma_drain_needed_fn
*dma_drain_needed
,
953 void *buf
, unsigned int size
);
954 extern void blk_queue_lld_busy(struct request_queue
*q
, lld_busy_fn
*fn
);
955 extern void blk_queue_segment_boundary(struct request_queue
*, unsigned long);
956 extern void blk_queue_prep_rq(struct request_queue
*, prep_rq_fn
*pfn
);
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 struct backing_dev_info
*blk_get_backing_dev_info(struct block_device
*bdev
);
964 extern int blk_queue_ordered(struct request_queue
*, unsigned, prepare_flush_fn
*);
965 extern bool blk_do_ordered(struct request_queue
*, struct request
**);
966 extern unsigned blk_ordered_cur_seq(struct request_queue
*);
967 extern unsigned blk_ordered_req_seq(struct request
*);
968 extern bool blk_ordered_complete_seq(struct request_queue
*, unsigned, int);
970 extern int blk_rq_map_sg(struct request_queue
*, struct request
*, struct scatterlist
*);
971 extern void blk_dump_rq_flags(struct request
*, char *);
972 extern void generic_unplug_device(struct request_queue
*);
973 extern long nr_blockdev_pages(void);
975 int 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
*);
983 #define blk_rq_tagged(rq) ((rq)->cmd_flags & REQ_QUEUED)
984 extern int blk_queue_start_tag(struct request_queue
*, struct request
*);
985 extern struct request
*blk_queue_find_tag(struct request_queue
*, int);
986 extern void blk_queue_end_tag(struct request_queue
*, struct request
*);
987 extern int blk_queue_init_tags(struct request_queue
*, int, struct blk_queue_tag
*);
988 extern void blk_queue_free_tags(struct request_queue
*);
989 extern int blk_queue_resize_tags(struct request_queue
*, int);
990 extern void blk_queue_invalidate_tags(struct request_queue
*);
991 extern struct blk_queue_tag
*blk_init_tags(int);
992 extern void blk_free_tags(struct blk_queue_tag
*);
994 static inline struct request
*blk_map_queue_find_tag(struct blk_queue_tag
*bqt
,
997 if (unlikely(bqt
== NULL
|| tag
>= bqt
->real_max_depth
))
999 return bqt
->tag_index
[tag
];
1002 extern int blkdev_issue_flush(struct block_device
*, sector_t
*);
1003 #define DISCARD_FL_WAIT 0x01 /* wait for completion */
1004 #define DISCARD_FL_BARRIER 0x02 /* issue DISCARD_BARRIER request */
1005 extern int blkdev_issue_discard(struct block_device
*, sector_t sector
,
1006 sector_t nr_sects
, gfp_t
, int flags
);
1008 static inline int sb_issue_discard(struct super_block
*sb
,
1009 sector_t block
, sector_t nr_blocks
)
1011 block
<<= (sb
->s_blocksize_bits
- 9);
1012 nr_blocks
<<= (sb
->s_blocksize_bits
- 9);
1013 return blkdev_issue_discard(sb
->s_bdev
, block
, nr_blocks
, GFP_KERNEL
,
1014 DISCARD_FL_BARRIER
);
1017 extern int blk_verify_command(unsigned char *cmd
, fmode_t has_write_perm
);
1019 #define MAX_PHYS_SEGMENTS 128
1020 #define MAX_HW_SEGMENTS 128
1021 #define SAFE_MAX_SECTORS 255
1022 #define BLK_DEF_MAX_SECTORS 1024
1024 #define MAX_SEGMENT_SIZE 65536
1026 #define BLK_SEG_BOUNDARY_MASK 0xFFFFFFFFUL
1028 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
1030 static inline unsigned long queue_bounce_pfn(struct request_queue
*q
)
1032 return q
->limits
.bounce_pfn
;
1035 static inline unsigned long queue_segment_boundary(struct request_queue
*q
)
1037 return q
->limits
.seg_boundary_mask
;
1040 static inline unsigned int queue_max_sectors(struct request_queue
*q
)
1042 return q
->limits
.max_sectors
;
1045 static inline unsigned int queue_max_hw_sectors(struct request_queue
*q
)
1047 return q
->limits
.max_hw_sectors
;
1050 static inline unsigned short queue_max_hw_segments(struct request_queue
*q
)
1052 return q
->limits
.max_hw_segments
;
1055 static inline unsigned short queue_max_phys_segments(struct request_queue
*q
)
1057 return q
->limits
.max_phys_segments
;
1060 static inline unsigned int queue_max_segment_size(struct request_queue
*q
)
1062 return q
->limits
.max_segment_size
;
1065 static inline unsigned short queue_logical_block_size(struct request_queue
*q
)
1069 if (q
&& q
->limits
.logical_block_size
)
1070 retval
= q
->limits
.logical_block_size
;
1075 static inline unsigned short bdev_logical_block_size(struct block_device
*bdev
)
1077 return queue_logical_block_size(bdev_get_queue(bdev
));
1080 static inline unsigned int queue_physical_block_size(struct request_queue
*q
)
1082 return q
->limits
.physical_block_size
;
1085 static inline int bdev_physical_block_size(struct block_device
*bdev
)
1087 return queue_physical_block_size(bdev_get_queue(bdev
));
1090 static inline unsigned int queue_io_min(struct request_queue
*q
)
1092 return q
->limits
.io_min
;
1095 static inline int bdev_io_min(struct block_device
*bdev
)
1097 return queue_io_min(bdev_get_queue(bdev
));
1100 static inline unsigned int queue_io_opt(struct request_queue
*q
)
1102 return q
->limits
.io_opt
;
1105 static inline int bdev_io_opt(struct block_device
*bdev
)
1107 return queue_io_opt(bdev_get_queue(bdev
));
1110 static inline int queue_alignment_offset(struct request_queue
*q
)
1112 if (q
->limits
.misaligned
)
1115 return q
->limits
.alignment_offset
;
1118 static inline int queue_sector_alignment_offset(struct request_queue
*q
,
1121 return ((sector
<< 9) - q
->limits
.alignment_offset
)
1122 & (q
->limits
.io_min
- 1);
1125 static inline int bdev_alignment_offset(struct block_device
*bdev
)
1127 struct request_queue
*q
= bdev_get_queue(bdev
);
1129 if (q
->limits
.misaligned
)
1132 if (bdev
!= bdev
->bd_contains
)
1133 return bdev
->bd_part
->alignment_offset
;
1135 return q
->limits
.alignment_offset
;
1138 static inline int queue_discard_alignment(struct request_queue
*q
)
1140 if (q
->limits
.discard_misaligned
)
1143 return q
->limits
.discard_alignment
;
1146 static inline int queue_sector_discard_alignment(struct request_queue
*q
,
1149 return ((sector
<< 9) - q
->limits
.discard_alignment
)
1150 & (q
->limits
.discard_granularity
- 1);
1153 static inline int queue_dma_alignment(struct request_queue
*q
)
1155 return q
? q
->dma_alignment
: 511;
1158 static inline int blk_rq_aligned(struct request_queue
*q
, void *addr
,
1161 unsigned int alignment
= queue_dma_alignment(q
) | q
->dma_pad_mask
;
1162 return !((unsigned long)addr
& alignment
) && !(len
& alignment
);
1165 /* assumes size > 256 */
1166 static inline unsigned int blksize_bits(unsigned int size
)
1168 unsigned int bits
= 8;
1172 } while (size
> 256);
1176 static inline unsigned int block_size(struct block_device
*bdev
)
1178 return bdev
->bd_block_size
;
1181 typedef struct {struct page
*v
;} Sector
;
1183 unsigned char *read_dev_sector(struct block_device
*, sector_t
, Sector
*);
1185 static inline void put_dev_sector(Sector p
)
1187 page_cache_release(p
.v
);
1191 int kblockd_schedule_work(struct request_queue
*q
, struct work_struct
*work
);
1193 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
1194 MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
1195 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
1196 MODULE_ALIAS("block-major-" __stringify(major) "-*")
1198 #if defined(CONFIG_BLK_DEV_INTEGRITY)
1200 #define INTEGRITY_FLAG_READ 2 /* verify data integrity on read */
1201 #define INTEGRITY_FLAG_WRITE 4 /* generate data integrity on write */
1203 struct blk_integrity_exchg
{
1207 unsigned int data_size
;
1208 unsigned short sector_size
;
1209 const char *disk_name
;
1212 typedef void (integrity_gen_fn
) (struct blk_integrity_exchg
*);
1213 typedef int (integrity_vrfy_fn
) (struct blk_integrity_exchg
*);
1214 typedef void (integrity_set_tag_fn
) (void *, void *, unsigned int);
1215 typedef void (integrity_get_tag_fn
) (void *, void *, unsigned int);
1217 struct blk_integrity
{
1218 integrity_gen_fn
*generate_fn
;
1219 integrity_vrfy_fn
*verify_fn
;
1220 integrity_set_tag_fn
*set_tag_fn
;
1221 integrity_get_tag_fn
*get_tag_fn
;
1223 unsigned short flags
;
1224 unsigned short tuple_size
;
1225 unsigned short sector_size
;
1226 unsigned short tag_size
;
1230 struct kobject kobj
;
1233 extern int blk_integrity_register(struct gendisk
*, struct blk_integrity
*);
1234 extern void blk_integrity_unregister(struct gendisk
*);
1235 extern int blk_integrity_compare(struct gendisk
*, struct gendisk
*);
1236 extern int blk_rq_map_integrity_sg(struct request
*, struct scatterlist
*);
1237 extern int blk_rq_count_integrity_sg(struct request
*);
1240 struct blk_integrity
*bdev_get_integrity(struct block_device
*bdev
)
1242 return bdev
->bd_disk
->integrity
;
1245 static inline struct blk_integrity
*blk_get_integrity(struct gendisk
*disk
)
1247 return disk
->integrity
;
1250 static inline int blk_integrity_rq(struct request
*rq
)
1252 if (rq
->bio
== NULL
)
1255 return bio_integrity(rq
->bio
);
1258 #else /* CONFIG_BLK_DEV_INTEGRITY */
1260 #define blk_integrity_rq(rq) (0)
1261 #define blk_rq_count_integrity_sg(a) (0)
1262 #define blk_rq_map_integrity_sg(a, b) (0)
1263 #define bdev_get_integrity(a) (0)
1264 #define blk_get_integrity(a) (0)
1265 #define blk_integrity_compare(a, b) (0)
1266 #define blk_integrity_register(a, b) (0)
1267 #define blk_integrity_unregister(a) do { } while (0);
1269 #endif /* CONFIG_BLK_DEV_INTEGRITY */
1271 struct block_device_operations
{
1272 int (*open
) (struct block_device
*, fmode_t
);
1273 int (*release
) (struct gendisk
*, fmode_t
);
1274 int (*locked_ioctl
) (struct block_device
*, fmode_t
, unsigned, unsigned long);
1275 int (*ioctl
) (struct block_device
*, fmode_t
, unsigned, unsigned long);
1276 int (*compat_ioctl
) (struct block_device
*, fmode_t
, unsigned, unsigned long);
1277 int (*direct_access
) (struct block_device
*, sector_t
,
1278 void **, unsigned long *);
1279 int (*media_changed
) (struct gendisk
*);
1280 unsigned long long (*set_capacity
) (struct gendisk
*,
1281 unsigned long long);
1282 int (*revalidate_disk
) (struct gendisk
*);
1283 int (*getgeo
)(struct block_device
*, struct hd_geometry
*);
1284 struct module
*owner
;
1287 extern int __blkdev_driver_ioctl(struct block_device
*, fmode_t
, unsigned int,
1289 #else /* CONFIG_BLOCK */
1291 * stubs for when the block layer is configured out
1293 #define buffer_heads_over_limit 0
1295 static inline long nr_blockdev_pages(void)
1300 #endif /* CONFIG_BLOCK */