1 #ifndef _LINUX_BLKDEV_H
2 #define _LINUX_BLKDEV_H
4 #include <linux/config.h>
5 #include <linux/major.h>
6 #include <linux/genhd.h>
7 #include <linux/list.h>
8 #include <linux/timer.h>
9 #include <linux/workqueue.h>
10 #include <linux/pagemap.h>
11 #include <linux/backing-dev.h>
12 #include <linux/wait.h>
13 #include <linux/mempool.h>
14 #include <linux/bio.h>
15 #include <linux/module.h>
16 #include <linux/stringify.h>
18 #include <asm/scatterlist.h>
21 typedef struct request_queue request_queue_t
;
22 struct elevator_queue
;
23 typedef struct elevator_queue elevator_t
;
24 struct request_pm_state
;
26 #define BLKDEV_MIN_RQ 4
27 #define BLKDEV_MAX_RQ 128 /* Default maximum */
30 * This is the per-process anticipatory I/O scheduler state.
32 struct as_io_context
{
35 void (*dtor
)(struct as_io_context
*aic
); /* destructor */
36 void (*exit
)(struct as_io_context
*aic
); /* called on task exit */
39 atomic_t nr_queued
; /* queued reads & sync writes */
40 atomic_t nr_dispatched
; /* number of requests gone to the drivers */
42 /* IO History tracking */
44 unsigned long last_end_request
;
45 unsigned long ttime_total
;
46 unsigned long ttime_samples
;
47 unsigned long ttime_mean
;
49 unsigned int seek_samples
;
50 sector_t last_request_pos
;
56 struct cfq_io_context
{
58 * circular list of cfq_io_contexts belonging to a process io context
60 struct list_head list
;
61 struct cfq_queue
*cfqq
;
64 struct io_context
*ioc
;
66 unsigned long last_end_request
;
67 unsigned long last_queue
;
68 unsigned long ttime_total
;
69 unsigned long ttime_samples
;
70 unsigned long ttime_mean
;
72 void (*dtor
)(struct cfq_io_context
*);
73 void (*exit
)(struct cfq_io_context
*);
77 * This is the per-process I/O subsystem state. It is refcounted and
78 * kmalloc'ed. Currently all fields are modified in process io context
79 * (apart from the atomic refcount), so require no locking.
83 struct task_struct
*task
;
85 int (*set_ioprio
)(struct io_context
*, unsigned int);
88 * For request batching
90 unsigned long last_waited
; /* Time last woken after wait for request */
91 int nr_batch_requests
; /* Number of requests left in the batch */
93 struct as_io_context
*aic
;
94 struct cfq_io_context
*cic
;
97 void put_io_context(struct io_context
*ioc
);
98 void exit_io_context(void);
99 struct io_context
*get_io_context(int gfp_flags
);
100 void copy_io_context(struct io_context
**pdst
, struct io_context
**psrc
);
101 void swap_io_context(struct io_context
**ioc1
, struct io_context
**ioc2
);
104 typedef void (rq_end_io_fn
)(struct request
*);
106 struct request_list
{
110 wait_queue_head_t wait
[2];
111 wait_queue_head_t drain
;
114 #define BLK_MAX_CDB 16
117 * try to put the fields that are referenced together in the same cacheline
120 struct list_head queuelist
; /* looking for ->queue? you must _not_
121 * access it directly, use
122 * blkdev_dequeue_request! */
123 unsigned long flags
; /* see REQ_ bits below */
125 /* Maintain bio traversal state for part by part I/O submission.
126 * hard_* are block layer internals, no driver should touch them!
129 sector_t sector
; /* next sector to submit */
130 unsigned long nr_sectors
; /* no. of sectors left to submit */
131 /* no. of sectors left to submit in the current segment */
132 unsigned int current_nr_sectors
;
134 sector_t hard_sector
; /* next sector to complete */
135 unsigned long hard_nr_sectors
; /* no. of sectors left to complete */
136 /* no. of sectors left to complete in the current segment */
137 unsigned int hard_cur_sectors
;
142 void *elevator_private
;
144 unsigned short ioprio
;
146 int rq_status
; /* should split this into a few status bits */
147 struct gendisk
*rq_disk
;
149 unsigned long start_time
;
151 /* Number of scatter-gather DMA addr+len pairs after
152 * physical address coalescing is performed.
154 unsigned short nr_phys_segments
;
156 /* Number of scatter-gather addr+len pairs after
157 * physical and DMA remapping hardware coalescing is performed.
158 * This is the number of scatter-gather entries the driver
159 * will actually have to deal with after DMA mapping is done.
161 unsigned short nr_hw_segments
;
168 struct request_list
*rl
;
170 struct completion
*waiting
;
174 * when request is used as a packet command carrier
176 unsigned int cmd_len
;
177 unsigned char cmd
[BLK_MAX_CDB
];
179 unsigned int data_len
;
182 unsigned int sense_len
;
185 unsigned int timeout
;
188 * For Power Management requests
190 struct request_pm_state
*pm
;
193 * completion callback. end_io_data should be folded in with waiting
195 rq_end_io_fn
*end_io
;
200 * first three bits match BIO_RW* bits, important
203 __REQ_RW
, /* not set, read. set, write */
204 __REQ_FAILFAST
, /* no low level driver retries */
205 __REQ_SOFTBARRIER
, /* may not be passed by ioscheduler */
206 __REQ_HARDBARRIER
, /* may not be passed by drive either */
207 __REQ_CMD
, /* is a regular fs rw request */
208 __REQ_NOMERGE
, /* don't touch this for merging */
209 __REQ_STARTED
, /* drive already may have started this one */
210 __REQ_DONTPREP
, /* don't call prep for this one */
211 __REQ_QUEUED
, /* uses queueing */
213 * for ATA/ATAPI devices
215 __REQ_PC
, /* packet command (special) */
216 __REQ_BLOCK_PC
, /* queued down pc from block layer */
217 __REQ_SENSE
, /* sense retrival */
219 __REQ_FAILED
, /* set if the request failed */
220 __REQ_QUIET
, /* don't worry about errors */
221 __REQ_SPECIAL
, /* driver suplied command */
224 __REQ_DRIVE_TASKFILE
,
225 __REQ_PREEMPT
, /* set for "ide_preempt" requests */
226 __REQ_PM_SUSPEND
, /* suspend request */
227 __REQ_PM_RESUME
, /* resume request */
228 __REQ_PM_SHUTDOWN
, /* shutdown request */
229 __REQ_BAR_PREFLUSH
, /* barrier pre-flush done */
230 __REQ_BAR_POSTFLUSH
, /* barrier post-flush */
231 __REQ_BAR_FLUSH
, /* rq is the flush request */
232 __REQ_NR_BITS
, /* stops here */
235 #define REQ_RW (1 << __REQ_RW)
236 #define REQ_FAILFAST (1 << __REQ_FAILFAST)
237 #define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER)
238 #define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER)
239 #define REQ_CMD (1 << __REQ_CMD)
240 #define REQ_NOMERGE (1 << __REQ_NOMERGE)
241 #define REQ_STARTED (1 << __REQ_STARTED)
242 #define REQ_DONTPREP (1 << __REQ_DONTPREP)
243 #define REQ_QUEUED (1 << __REQ_QUEUED)
244 #define REQ_PC (1 << __REQ_PC)
245 #define REQ_BLOCK_PC (1 << __REQ_BLOCK_PC)
246 #define REQ_SENSE (1 << __REQ_SENSE)
247 #define REQ_FAILED (1 << __REQ_FAILED)
248 #define REQ_QUIET (1 << __REQ_QUIET)
249 #define REQ_SPECIAL (1 << __REQ_SPECIAL)
250 #define REQ_DRIVE_CMD (1 << __REQ_DRIVE_CMD)
251 #define REQ_DRIVE_TASK (1 << __REQ_DRIVE_TASK)
252 #define REQ_DRIVE_TASKFILE (1 << __REQ_DRIVE_TASKFILE)
253 #define REQ_PREEMPT (1 << __REQ_PREEMPT)
254 #define REQ_PM_SUSPEND (1 << __REQ_PM_SUSPEND)
255 #define REQ_PM_RESUME (1 << __REQ_PM_RESUME)
256 #define REQ_PM_SHUTDOWN (1 << __REQ_PM_SHUTDOWN)
257 #define REQ_BAR_PREFLUSH (1 << __REQ_BAR_PREFLUSH)
258 #define REQ_BAR_POSTFLUSH (1 << __REQ_BAR_POSTFLUSH)
259 #define REQ_BAR_FLUSH (1 << __REQ_BAR_FLUSH)
262 * State information carried for REQ_PM_SUSPEND and REQ_PM_RESUME
263 * requests. Some step values could eventually be made generic.
265 struct request_pm_state
267 /* PM state machine step value, currently driver specific */
269 /* requested PM state value (S1, S2, S3, S4, ...) */
271 void* data
; /* for driver use */
274 #include <linux/elevator.h>
276 typedef int (merge_request_fn
) (request_queue_t
*, struct request
*,
278 typedef int (merge_requests_fn
) (request_queue_t
*, struct request
*,
280 typedef void (request_fn_proc
) (request_queue_t
*q
);
281 typedef int (make_request_fn
) (request_queue_t
*q
, struct bio
*bio
);
282 typedef int (prep_rq_fn
) (request_queue_t
*, struct request
*);
283 typedef void (unplug_fn
) (request_queue_t
*);
286 typedef int (merge_bvec_fn
) (request_queue_t
*, struct bio
*, struct bio_vec
*);
287 typedef void (activity_fn
) (void *data
, int rw
);
288 typedef int (issue_flush_fn
) (request_queue_t
*, struct gendisk
*, sector_t
*);
289 typedef int (prepare_flush_fn
) (request_queue_t
*, struct request
*);
290 typedef void (end_flush_fn
) (request_queue_t
*, struct request
*);
292 enum blk_queue_state
{
297 struct blk_queue_tag
{
298 struct request
**tag_index
; /* map of busy tags */
299 unsigned long *tag_map
; /* bit map of free/busy tags */
300 struct list_head busy_list
; /* fifo list of busy tags */
301 int busy
; /* current depth */
302 int max_depth
; /* what we will send to device */
303 atomic_t refcnt
; /* map can be shared */
309 * Together with queue_head for cacheline sharing
311 struct list_head queue_head
;
312 struct request
*last_merge
;
313 elevator_t
*elevator
;
316 * the queue request freelist, one for reads and one for writes
318 struct request_list rq
;
320 request_fn_proc
*request_fn
;
321 merge_request_fn
*back_merge_fn
;
322 merge_request_fn
*front_merge_fn
;
323 merge_requests_fn
*merge_requests_fn
;
324 make_request_fn
*make_request_fn
;
325 prep_rq_fn
*prep_rq_fn
;
326 unplug_fn
*unplug_fn
;
327 merge_bvec_fn
*merge_bvec_fn
;
328 activity_fn
*activity_fn
;
329 issue_flush_fn
*issue_flush_fn
;
330 prepare_flush_fn
*prepare_flush_fn
;
331 end_flush_fn
*end_flush_fn
;
334 * Auto-unplugging state
336 struct timer_list unplug_timer
;
337 int unplug_thresh
; /* After this many requests */
338 unsigned long unplug_delay
; /* After this many jiffies */
339 struct work_struct unplug_work
;
341 struct backing_dev_info backing_dev_info
;
344 * The queue owner gets to use this for whatever they like.
345 * ll_rw_blk doesn't touch it.
352 * queue needs bounce pages for pages above this limit
354 unsigned long bounce_pfn
;
355 unsigned int bounce_gfp
;
358 * various queue flags, see QUEUE_* below
360 unsigned long queue_flags
;
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 unsigned long nr_requests
; /* Max # of requests */
379 unsigned int nr_congestion_on
;
380 unsigned int nr_congestion_off
;
381 unsigned int nr_batching
;
383 unsigned short max_sectors
;
384 unsigned short max_hw_sectors
;
385 unsigned short max_phys_segments
;
386 unsigned short max_hw_segments
;
387 unsigned short hardsect_size
;
388 unsigned int max_segment_size
;
390 unsigned long seg_boundary_mask
;
391 unsigned int dma_alignment
;
393 struct blk_queue_tag
*queue_tags
;
397 unsigned int in_flight
;
402 unsigned int sg_timeout
;
403 unsigned int sg_reserved_size
;
406 struct list_head drain_list
;
409 * reserved for flush operations
411 struct request
*flush_rq
;
412 unsigned char ordered
;
421 #define RQ_INACTIVE (-1)
423 #define RQ_SCSI_BUSY 0xffff
424 #define RQ_SCSI_DONE 0xfffe
425 #define RQ_SCSI_DISCONNECTING 0xffe0
427 #define QUEUE_FLAG_CLUSTER 0 /* cluster several segments into 1 */
428 #define QUEUE_FLAG_QUEUED 1 /* uses generic tag queueing */
429 #define QUEUE_FLAG_STOPPED 2 /* queue is stopped */
430 #define QUEUE_FLAG_READFULL 3 /* write queue has been filled */
431 #define QUEUE_FLAG_WRITEFULL 4 /* read queue has been filled */
432 #define QUEUE_FLAG_DEAD 5 /* queue being torn down */
433 #define QUEUE_FLAG_REENTER 6 /* Re-entrancy avoidance */
434 #define QUEUE_FLAG_PLUGGED 7 /* queue is plugged */
435 #define QUEUE_FLAG_DRAIN 8 /* draining queue for sched switch */
436 #define QUEUE_FLAG_FLUSH 9 /* doing barrier flush sequence */
438 #define blk_queue_plugged(q) test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
439 #define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
440 #define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
441 #define blk_queue_flushing(q) test_bit(QUEUE_FLAG_FLUSH, &(q)->queue_flags)
443 #define blk_fs_request(rq) ((rq)->flags & REQ_CMD)
444 #define blk_pc_request(rq) ((rq)->flags & REQ_BLOCK_PC)
445 #define blk_noretry_request(rq) ((rq)->flags & REQ_FAILFAST)
446 #define blk_rq_started(rq) ((rq)->flags & REQ_STARTED)
448 #define blk_account_rq(rq) (blk_rq_started(rq) && blk_fs_request(rq))
450 #define blk_pm_suspend_request(rq) ((rq)->flags & REQ_PM_SUSPEND)
451 #define blk_pm_resume_request(rq) ((rq)->flags & REQ_PM_RESUME)
452 #define blk_pm_request(rq) \
453 ((rq)->flags & (REQ_PM_SUSPEND | REQ_PM_RESUME))
455 #define blk_barrier_rq(rq) ((rq)->flags & REQ_HARDBARRIER)
456 #define blk_barrier_preflush(rq) ((rq)->flags & REQ_BAR_PREFLUSH)
457 #define blk_barrier_postflush(rq) ((rq)->flags & REQ_BAR_POSTFLUSH)
459 #define list_entry_rq(ptr) list_entry((ptr), struct request, queuelist)
461 #define rq_data_dir(rq) ((rq)->flags & 1)
463 static inline int blk_queue_full(struct request_queue
*q
, int rw
)
466 return test_bit(QUEUE_FLAG_READFULL
, &q
->queue_flags
);
467 return test_bit(QUEUE_FLAG_WRITEFULL
, &q
->queue_flags
);
470 static inline void blk_set_queue_full(struct request_queue
*q
, int rw
)
473 set_bit(QUEUE_FLAG_READFULL
, &q
->queue_flags
);
475 set_bit(QUEUE_FLAG_WRITEFULL
, &q
->queue_flags
);
478 static inline void blk_clear_queue_full(struct request_queue
*q
, int rw
)
481 clear_bit(QUEUE_FLAG_READFULL
, &q
->queue_flags
);
483 clear_bit(QUEUE_FLAG_WRITEFULL
, &q
->queue_flags
);
488 * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
489 * it already be started by driver.
491 #define RQ_NOMERGE_FLAGS \
492 (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER)
493 #define rq_mergeable(rq) \
494 (!((rq)->flags & RQ_NOMERGE_FLAGS) && blk_fs_request((rq)))
497 * noop, requests are automagically marked as active/inactive by I/O
498 * scheduler -- see elv_next_request
500 #define blk_queue_headactive(q, head_active)
503 * q->prep_rq_fn return values
505 #define BLKPREP_OK 0 /* serve it */
506 #define BLKPREP_KILL 1 /* fatal error, kill */
507 #define BLKPREP_DEFER 2 /* leave on queue */
509 extern unsigned long blk_max_low_pfn
, blk_max_pfn
;
512 * standard bounce addresses:
514 * BLK_BOUNCE_HIGH : bounce all highmem pages
515 * BLK_BOUNCE_ANY : don't bounce anything
516 * BLK_BOUNCE_ISA : bounce pages above ISA DMA boundary
518 #define BLK_BOUNCE_HIGH ((u64)blk_max_low_pfn << PAGE_SHIFT)
519 #define BLK_BOUNCE_ANY ((u64)blk_max_pfn << PAGE_SHIFT)
520 #define BLK_BOUNCE_ISA (ISA_DMA_THRESHOLD)
523 extern int init_emergency_isa_pool(void);
524 extern void blk_queue_bounce(request_queue_t
*q
, struct bio
**bio
);
526 static inline int init_emergency_isa_pool(void)
530 static inline void blk_queue_bounce(request_queue_t
*q
, struct bio
**bio
)
533 #endif /* CONFIG_MMU */
535 #define rq_for_each_bio(_bio, rq) \
537 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
541 unsigned block_size_bits
;
544 extern int blk_register_queue(struct gendisk
*disk
);
545 extern void blk_unregister_queue(struct gendisk
*disk
);
546 extern void register_disk(struct gendisk
*dev
);
547 extern void generic_make_request(struct bio
*bio
);
548 extern void blk_put_request(struct request
*);
549 extern void blk_end_sync_rq(struct request
*rq
);
550 extern void blk_attempt_remerge(request_queue_t
*, struct request
*);
551 extern struct request
*blk_get_request(request_queue_t
*, int, int);
552 extern void blk_insert_request(request_queue_t
*, struct request
*, int, void *);
553 extern void blk_requeue_request(request_queue_t
*, struct request
*);
554 extern void blk_plug_device(request_queue_t
*);
555 extern int blk_remove_plug(request_queue_t
*);
556 extern void blk_recount_segments(request_queue_t
*, struct bio
*);
557 extern int scsi_cmd_ioctl(struct file
*, struct gendisk
*, unsigned int, void __user
*);
558 extern void blk_start_queue(request_queue_t
*q
);
559 extern void blk_stop_queue(request_queue_t
*q
);
560 extern void blk_sync_queue(struct request_queue
*q
);
561 extern void __blk_stop_queue(request_queue_t
*q
);
562 extern void blk_run_queue(request_queue_t
*);
563 extern void blk_queue_activity_fn(request_queue_t
*, activity_fn
*, void *);
564 extern struct request
*blk_rq_map_user(request_queue_t
*, int, void __user
*, unsigned int);
565 extern int blk_rq_unmap_user(struct request
*, struct bio
*, unsigned int);
566 extern int blk_execute_rq(request_queue_t
*, struct gendisk
*, struct request
*);
568 static inline request_queue_t
*bdev_get_queue(struct block_device
*bdev
)
570 return bdev
->bd_disk
->queue
;
573 static inline void blk_run_backing_dev(struct backing_dev_info
*bdi
,
576 if (bdi
&& bdi
->unplug_io_fn
)
577 bdi
->unplug_io_fn(bdi
, page
);
580 static inline void blk_run_address_space(struct address_space
*mapping
)
583 blk_run_backing_dev(mapping
->backing_dev_info
, NULL
);
587 * end_request() and friends. Must be called with the request queue spinlock
588 * acquired. All functions called within end_request() _must_be_ atomic.
590 * Several drivers define their own end_request and call
591 * end_that_request_first() and end_that_request_last()
592 * for parts of the original function. This prevents
593 * code duplication in drivers.
595 extern int end_that_request_first(struct request
*, int, int);
596 extern int end_that_request_chunk(struct request
*, int, int);
597 extern void end_that_request_last(struct request
*);
598 extern void end_request(struct request
*req
, int uptodate
);
601 * end_that_request_first/chunk() takes an uptodate argument. we account
602 * any value <= as an io error. 0 means -EIO for compatability reasons,
603 * any other < 0 value is the direct error type. An uptodate value of
604 * 1 indicates successful io completion
606 #define end_io_error(uptodate) (unlikely((uptodate) <= 0))
608 static inline void blkdev_dequeue_request(struct request
*req
)
610 BUG_ON(list_empty(&req
->queuelist
));
612 list_del_init(&req
->queuelist
);
615 elv_remove_request(req
->q
, req
);
619 * Access functions for manipulating queue properties
621 extern request_queue_t
*blk_init_queue_node(request_fn_proc
*rfn
,
622 spinlock_t
*lock
, int node_id
);
623 extern request_queue_t
*blk_init_queue(request_fn_proc
*, spinlock_t
*);
624 extern void blk_cleanup_queue(request_queue_t
*);
625 extern void blk_queue_make_request(request_queue_t
*, make_request_fn
*);
626 extern void blk_queue_bounce_limit(request_queue_t
*, u64
);
627 extern void blk_queue_max_sectors(request_queue_t
*, unsigned short);
628 extern void blk_queue_max_phys_segments(request_queue_t
*, unsigned short);
629 extern void blk_queue_max_hw_segments(request_queue_t
*, unsigned short);
630 extern void blk_queue_max_segment_size(request_queue_t
*, unsigned int);
631 extern void blk_queue_hardsect_size(request_queue_t
*, unsigned short);
632 extern void blk_queue_stack_limits(request_queue_t
*t
, request_queue_t
*b
);
633 extern void blk_queue_segment_boundary(request_queue_t
*, unsigned long);
634 extern void blk_queue_prep_rq(request_queue_t
*, prep_rq_fn
*pfn
);
635 extern void blk_queue_merge_bvec(request_queue_t
*, merge_bvec_fn
*);
636 extern void blk_queue_dma_alignment(request_queue_t
*, int);
637 extern struct backing_dev_info
*blk_get_backing_dev_info(struct block_device
*bdev
);
638 extern void blk_queue_ordered(request_queue_t
*, int);
639 extern void blk_queue_issue_flush_fn(request_queue_t
*, issue_flush_fn
*);
640 extern struct request
*blk_start_pre_flush(request_queue_t
*,struct request
*);
641 extern int blk_complete_barrier_rq(request_queue_t
*, struct request
*, int);
642 extern int blk_complete_barrier_rq_locked(request_queue_t
*, struct request
*, int);
644 extern int blk_rq_map_sg(request_queue_t
*, struct request
*, struct scatterlist
*);
645 extern void blk_dump_rq_flags(struct request
*, char *);
646 extern void generic_unplug_device(request_queue_t
*);
647 extern void __generic_unplug_device(request_queue_t
*);
648 extern long nr_blockdev_pages(void);
649 extern void blk_wait_queue_drained(request_queue_t
*, int);
650 extern void blk_finish_queue_drain(request_queue_t
*);
652 int blk_get_queue(request_queue_t
*);
653 request_queue_t
*blk_alloc_queue(int gfp_mask
);
654 request_queue_t
*blk_alloc_queue_node(int,int);
655 #define blk_put_queue(q) blk_cleanup_queue((q))
660 #define blk_queue_tag_depth(q) ((q)->queue_tags->busy)
661 #define blk_queue_tag_queue(q) ((q)->queue_tags->busy < (q)->queue_tags->max_depth)
662 #define blk_rq_tagged(rq) ((rq)->flags & REQ_QUEUED)
663 extern int blk_queue_start_tag(request_queue_t
*, struct request
*);
664 extern struct request
*blk_queue_find_tag(request_queue_t
*, int);
665 extern void blk_queue_end_tag(request_queue_t
*, struct request
*);
666 extern int blk_queue_init_tags(request_queue_t
*, int, struct blk_queue_tag
*);
667 extern void blk_queue_free_tags(request_queue_t
*);
668 extern int blk_queue_resize_tags(request_queue_t
*, int);
669 extern void blk_queue_invalidate_tags(request_queue_t
*);
670 extern long blk_congestion_wait(int rw
, long timeout
);
672 extern void blk_rq_bio_prep(request_queue_t
*, struct request
*, struct bio
*);
673 extern int blkdev_issue_flush(struct block_device
*, sector_t
*);
675 #define MAX_PHYS_SEGMENTS 128
676 #define MAX_HW_SEGMENTS 128
677 #define MAX_SECTORS 255
679 #define MAX_SEGMENT_SIZE 65536
681 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
683 static inline int queue_hardsect_size(request_queue_t
*q
)
687 if (q
&& q
->hardsect_size
)
688 retval
= q
->hardsect_size
;
693 static inline int bdev_hardsect_size(struct block_device
*bdev
)
695 return queue_hardsect_size(bdev_get_queue(bdev
));
698 static inline int queue_dma_alignment(request_queue_t
*q
)
702 if (q
&& q
->dma_alignment
)
703 retval
= q
->dma_alignment
;
708 static inline int bdev_dma_aligment(struct block_device
*bdev
)
710 return queue_dma_alignment(bdev_get_queue(bdev
));
713 #define blk_finished_io(nsects) do { } while (0)
714 #define blk_started_io(nsects) do { } while (0)
716 /* assumes size > 256 */
717 static inline unsigned int blksize_bits(unsigned int size
)
719 unsigned int bits
= 8;
723 } while (size
> 256);
727 extern inline unsigned int block_size(struct block_device
*bdev
)
729 return bdev
->bd_block_size
;
732 typedef struct {struct page
*v
;} Sector
;
734 unsigned char *read_dev_sector(struct block_device
*, sector_t
, Sector
*);
736 static inline void put_dev_sector(Sector p
)
738 page_cache_release(p
.v
);
742 int kblockd_schedule_work(struct work_struct
*work
);
743 void kblockd_flush(void);
746 # include <asm/div64.h>
747 # define sector_div(a, b) do_div(a, b)
749 # define sector_div(n, b)( \
759 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
760 MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
761 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
762 MODULE_ALIAS("block-major-" __stringify(major) "-*")