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) "-*")