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/bsg.h>
21 #include <asm/scatterlist.h>
23 struct scsi_ioctl_command
;
26 typedef struct request_queue request_queue_t __deprecated
;
27 struct elevator_queue
;
28 typedef struct elevator_queue elevator_t
;
29 struct request_pm_state
;
34 #define BLKDEV_MIN_RQ 4
35 #define BLKDEV_MAX_RQ 128 /* Default maximum */
37 int put_io_context(struct io_context
*ioc
);
38 void exit_io_context(void);
39 struct io_context
*get_io_context(gfp_t gfp_flags
, int node
);
40 struct io_context
*alloc_io_context(gfp_t gfp_flags
, int node
);
41 void copy_io_context(struct io_context
**pdst
, struct io_context
**psrc
);
44 typedef void (rq_end_io_fn
)(struct request
*, int);
51 wait_queue_head_t wait
[2];
55 * request command types
57 enum rq_cmd_type_bits
{
58 REQ_TYPE_FS
= 1, /* fs request */
59 REQ_TYPE_BLOCK_PC
, /* scsi command */
60 REQ_TYPE_SENSE
, /* sense request */
61 REQ_TYPE_PM_SUSPEND
, /* suspend request */
62 REQ_TYPE_PM_RESUME
, /* resume request */
63 REQ_TYPE_PM_SHUTDOWN
, /* shutdown request */
64 REQ_TYPE_FLUSH
, /* flush request */
65 REQ_TYPE_SPECIAL
, /* driver defined type */
66 REQ_TYPE_LINUX_BLOCK
, /* generic block layer message */
68 * for ATA/ATAPI devices. this really doesn't belong here, ide should
69 * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver
70 * private REQ_LB opcodes to differentiate what type of request this is
72 REQ_TYPE_ATA_TASKFILE
,
77 * For request of type REQ_TYPE_LINUX_BLOCK, rq->cmd[0] is the opcode being
78 * sent down (similar to how REQ_TYPE_BLOCK_PC means that ->cmd[] holds a
81 * 0x00 -> 0x3f are driver private, to be used for whatever purpose they need,
82 * typically to differentiate REQ_TYPE_SPECIAL requests.
87 * just examples for now
89 REQ_LB_OP_EJECT
= 0x40, /* eject request */
90 REQ_LB_OP_FLUSH
= 0x41, /* flush device */
94 * request type modified bits. first three bits match BIO_RW* bits, important
97 __REQ_RW
, /* not set, read. set, write */
98 __REQ_FAILFAST
, /* no low level driver retries */
99 __REQ_SORTED
, /* elevator knows about this request */
100 __REQ_SOFTBARRIER
, /* may not be passed by ioscheduler */
101 __REQ_HARDBARRIER
, /* may not be passed by drive either */
102 __REQ_FUA
, /* forced unit access */
103 __REQ_NOMERGE
, /* don't touch this for merging */
104 __REQ_STARTED
, /* drive already may have started this one */
105 __REQ_DONTPREP
, /* don't call prep for this one */
106 __REQ_QUEUED
, /* uses queueing */
107 __REQ_ELVPRIV
, /* elevator private data attached */
108 __REQ_FAILED
, /* set if the request failed */
109 __REQ_QUIET
, /* don't worry about errors */
110 __REQ_PREEMPT
, /* set for "ide_preempt" requests */
111 __REQ_ORDERED_COLOR
, /* is before or after barrier */
112 __REQ_RW_SYNC
, /* request is sync (O_DIRECT) */
113 __REQ_ALLOCED
, /* request came from our alloc pool */
114 __REQ_RW_META
, /* metadata io request */
115 __REQ_COPY_USER
, /* contains copies of user pages */
116 __REQ_NR_BITS
, /* stops here */
119 #define REQ_RW (1 << __REQ_RW)
120 #define REQ_FAILFAST (1 << __REQ_FAILFAST)
121 #define REQ_SORTED (1 << __REQ_SORTED)
122 #define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER)
123 #define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER)
124 #define REQ_FUA (1 << __REQ_FUA)
125 #define REQ_NOMERGE (1 << __REQ_NOMERGE)
126 #define REQ_STARTED (1 << __REQ_STARTED)
127 #define REQ_DONTPREP (1 << __REQ_DONTPREP)
128 #define REQ_QUEUED (1 << __REQ_QUEUED)
129 #define REQ_ELVPRIV (1 << __REQ_ELVPRIV)
130 #define REQ_FAILED (1 << __REQ_FAILED)
131 #define REQ_QUIET (1 << __REQ_QUIET)
132 #define REQ_PREEMPT (1 << __REQ_PREEMPT)
133 #define REQ_ORDERED_COLOR (1 << __REQ_ORDERED_COLOR)
134 #define REQ_RW_SYNC (1 << __REQ_RW_SYNC)
135 #define REQ_ALLOCED (1 << __REQ_ALLOCED)
136 #define REQ_RW_META (1 << __REQ_RW_META)
137 #define REQ_COPY_USER (1 << __REQ_COPY_USER)
139 #define BLK_MAX_CDB 16
142 * try to put the fields that are referenced together in the same cacheline.
143 * if you modify this structure, be sure to check block/blk-core.c:rq_init()
147 struct list_head queuelist
;
148 struct list_head donelist
;
150 struct request_queue
*q
;
152 unsigned int cmd_flags
;
153 enum rq_cmd_type_bits cmd_type
;
155 /* Maintain bio traversal state for part by part I/O submission.
156 * hard_* are block layer internals, no driver should touch them!
159 sector_t sector
; /* next sector to submit */
160 sector_t hard_sector
; /* next sector to complete */
161 unsigned long nr_sectors
; /* no. of sectors left to submit */
162 unsigned long hard_nr_sectors
; /* no. of sectors left to complete */
163 /* no. of sectors left to submit in the current segment */
164 unsigned int current_nr_sectors
;
166 /* no. of sectors left to complete in the current segment */
167 unsigned int hard_cur_sectors
;
172 struct hlist_node hash
; /* merge hash */
174 * The rb_node is only used inside the io scheduler, requests
175 * are pruned when moved to the dispatch queue. So let the
176 * completion_data share space with the rb_node.
179 struct rb_node rb_node
; /* sort/lookup */
180 void *completion_data
;
184 * two pointers are available for the IO schedulers, if they need
185 * more they have to dynamically allocate it.
187 void *elevator_private
;
188 void *elevator_private2
;
190 struct gendisk
*rq_disk
;
191 unsigned long start_time
;
193 /* Number of scatter-gather DMA addr+len pairs after
194 * physical address coalescing is performed.
196 unsigned short nr_phys_segments
;
198 /* Number of scatter-gather addr+len pairs after
199 * physical and DMA remapping hardware coalescing is performed.
200 * This is the number of scatter-gather entries the driver
201 * will actually have to deal with after DMA mapping is done.
203 unsigned short nr_hw_segments
;
205 unsigned short ioprio
;
216 * when request is used as a packet command carrier
218 unsigned int cmd_len
;
219 unsigned char cmd
[BLK_MAX_CDB
];
221 unsigned int data_len
;
222 unsigned int extra_len
; /* length of alignment and padding */
223 unsigned int sense_len
;
227 unsigned int timeout
;
231 * completion callback.
233 rq_end_io_fn
*end_io
;
237 struct request
*next_rq
;
241 * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
242 * requests. Some step values could eventually be made generic.
244 struct request_pm_state
246 /* PM state machine step value, currently driver specific */
248 /* requested PM state value (S1, S2, S3, S4, ...) */
250 void* data
; /* for driver use */
253 #include <linux/elevator.h>
255 typedef void (request_fn_proc
) (struct request_queue
*q
);
256 typedef int (make_request_fn
) (struct request_queue
*q
, struct bio
*bio
);
257 typedef int (prep_rq_fn
) (struct request_queue
*, struct request
*);
258 typedef void (unplug_fn
) (struct request_queue
*);
261 typedef int (merge_bvec_fn
) (struct request_queue
*, struct bio
*, struct bio_vec
*);
262 typedef void (prepare_flush_fn
) (struct request_queue
*, struct request
*);
263 typedef void (softirq_done_fn
)(struct request
*);
264 typedef int (dma_drain_needed_fn
)(struct request
*);
266 enum blk_queue_state
{
271 struct blk_queue_tag
{
272 struct request
**tag_index
; /* map of busy tags */
273 unsigned long *tag_map
; /* bit map of free/busy tags */
274 int busy
; /* current depth */
275 int max_depth
; /* what we will send to device */
276 int real_max_depth
; /* what the array can hold */
277 atomic_t refcnt
; /* map can be shared */
283 * Together with queue_head for cacheline sharing
285 struct list_head queue_head
;
286 struct request
*last_merge
;
287 elevator_t
*elevator
;
290 * the queue request freelist, one for reads and one for writes
292 struct request_list rq
;
294 request_fn_proc
*request_fn
;
295 make_request_fn
*make_request_fn
;
296 prep_rq_fn
*prep_rq_fn
;
297 unplug_fn
*unplug_fn
;
298 merge_bvec_fn
*merge_bvec_fn
;
299 prepare_flush_fn
*prepare_flush_fn
;
300 softirq_done_fn
*softirq_done_fn
;
301 dma_drain_needed_fn
*dma_drain_needed
;
304 * Dispatch queue sorting
307 struct request
*boundary_rq
;
310 * Auto-unplugging state
312 struct timer_list unplug_timer
;
313 int unplug_thresh
; /* After this many requests */
314 unsigned long unplug_delay
; /* After this many jiffies */
315 struct work_struct unplug_work
;
317 struct backing_dev_info backing_dev_info
;
320 * The queue owner gets to use this for whatever they like.
321 * ll_rw_blk doesn't touch it.
326 * queue needs bounce pages for pages above this limit
328 unsigned long bounce_pfn
;
332 * various queue flags, see QUEUE_* below
334 unsigned long queue_flags
;
337 * protects queue structures from reentrancy. ->__queue_lock should
338 * _never_ be used directly, it is queue private. always use
341 spinlock_t __queue_lock
;
342 spinlock_t
*queue_lock
;
352 unsigned long nr_requests
; /* Max # of requests */
353 unsigned int nr_congestion_on
;
354 unsigned int nr_congestion_off
;
355 unsigned int nr_batching
;
357 unsigned int max_sectors
;
358 unsigned int max_hw_sectors
;
359 unsigned short max_phys_segments
;
360 unsigned short max_hw_segments
;
361 unsigned short hardsect_size
;
362 unsigned int max_segment_size
;
364 unsigned long seg_boundary_mask
;
365 void *dma_drain_buffer
;
366 unsigned int dma_drain_size
;
367 unsigned int dma_pad_mask
;
368 unsigned int dma_alignment
;
370 struct blk_queue_tag
*queue_tags
;
371 struct list_head tag_busy_list
;
373 unsigned int nr_sorted
;
374 unsigned int in_flight
;
379 unsigned int sg_timeout
;
380 unsigned int sg_reserved_size
;
382 #ifdef CONFIG_BLK_DEV_IO_TRACE
383 struct blk_trace
*blk_trace
;
386 * reserved for flush operations
388 unsigned int ordered
, next_ordered
, ordseq
;
389 int orderr
, ordcolor
;
390 struct request pre_flush_rq
, bar_rq
, post_flush_rq
;
391 struct request
*orig_bar_rq
;
393 struct mutex sysfs_lock
;
395 #if defined(CONFIG_BLK_DEV_BSG)
396 struct bsg_class_device bsg_dev
;
400 #define QUEUE_FLAG_CLUSTER 0 /* cluster several segments into 1 */
401 #define QUEUE_FLAG_QUEUED 1 /* uses generic tag queueing */
402 #define QUEUE_FLAG_STOPPED 2 /* queue is stopped */
403 #define QUEUE_FLAG_READFULL 3 /* read queue has been filled */
404 #define QUEUE_FLAG_WRITEFULL 4 /* write queue has been filled */
405 #define QUEUE_FLAG_DEAD 5 /* queue being torn down */
406 #define QUEUE_FLAG_REENTER 6 /* Re-entrancy avoidance */
407 #define QUEUE_FLAG_PLUGGED 7 /* queue is plugged */
408 #define QUEUE_FLAG_ELVSWITCH 8 /* don't use elevator, just do FIFO */
409 #define QUEUE_FLAG_BIDI 9 /* queue supports bidi requests */
413 * Hardbarrier is supported with one of the following methods.
415 * NONE : hardbarrier unsupported
416 * DRAIN : ordering by draining is enough
417 * DRAIN_FLUSH : ordering by draining w/ pre and post flushes
418 * DRAIN_FUA : ordering by draining w/ pre flush and FUA write
419 * TAG : ordering by tag is enough
420 * TAG_FLUSH : ordering by tag w/ pre and post flushes
421 * TAG_FUA : ordering by tag w/ pre flush and FUA write
423 QUEUE_ORDERED_NONE
= 0x00,
424 QUEUE_ORDERED_DRAIN
= 0x01,
425 QUEUE_ORDERED_TAG
= 0x02,
427 QUEUE_ORDERED_PREFLUSH
= 0x10,
428 QUEUE_ORDERED_POSTFLUSH
= 0x20,
429 QUEUE_ORDERED_FUA
= 0x40,
431 QUEUE_ORDERED_DRAIN_FLUSH
= QUEUE_ORDERED_DRAIN
|
432 QUEUE_ORDERED_PREFLUSH
| QUEUE_ORDERED_POSTFLUSH
,
433 QUEUE_ORDERED_DRAIN_FUA
= QUEUE_ORDERED_DRAIN
|
434 QUEUE_ORDERED_PREFLUSH
| QUEUE_ORDERED_FUA
,
435 QUEUE_ORDERED_TAG_FLUSH
= QUEUE_ORDERED_TAG
|
436 QUEUE_ORDERED_PREFLUSH
| QUEUE_ORDERED_POSTFLUSH
,
437 QUEUE_ORDERED_TAG_FUA
= QUEUE_ORDERED_TAG
|
438 QUEUE_ORDERED_PREFLUSH
| QUEUE_ORDERED_FUA
,
441 * Ordered operation sequence
443 QUEUE_ORDSEQ_STARTED
= 0x01, /* flushing in progress */
444 QUEUE_ORDSEQ_DRAIN
= 0x02, /* waiting for the queue to be drained */
445 QUEUE_ORDSEQ_PREFLUSH
= 0x04, /* pre-flushing in progress */
446 QUEUE_ORDSEQ_BAR
= 0x08, /* original barrier req in progress */
447 QUEUE_ORDSEQ_POSTFLUSH
= 0x10, /* post-flushing in progress */
448 QUEUE_ORDSEQ_DONE
= 0x20,
451 #define blk_queue_plugged(q) test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
452 #define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
453 #define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
454 #define blk_queue_flushing(q) ((q)->ordseq)
456 #define blk_fs_request(rq) ((rq)->cmd_type == REQ_TYPE_FS)
457 #define blk_pc_request(rq) ((rq)->cmd_type == REQ_TYPE_BLOCK_PC)
458 #define blk_special_request(rq) ((rq)->cmd_type == REQ_TYPE_SPECIAL)
459 #define blk_sense_request(rq) ((rq)->cmd_type == REQ_TYPE_SENSE)
461 #define blk_noretry_request(rq) ((rq)->cmd_flags & REQ_FAILFAST)
462 #define blk_rq_started(rq) ((rq)->cmd_flags & REQ_STARTED)
464 #define blk_account_rq(rq) (blk_rq_started(rq) && blk_fs_request(rq))
466 #define blk_pm_suspend_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND)
467 #define blk_pm_resume_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_RESUME)
468 #define blk_pm_request(rq) \
469 (blk_pm_suspend_request(rq) || blk_pm_resume_request(rq))
471 #define blk_sorted_rq(rq) ((rq)->cmd_flags & REQ_SORTED)
472 #define blk_barrier_rq(rq) ((rq)->cmd_flags & REQ_HARDBARRIER)
473 #define blk_fua_rq(rq) ((rq)->cmd_flags & REQ_FUA)
474 #define blk_bidi_rq(rq) ((rq)->next_rq != NULL)
475 #define blk_empty_barrier(rq) (blk_barrier_rq(rq) && blk_fs_request(rq) && !(rq)->hard_nr_sectors)
476 /* rq->queuelist of dequeued request must be list_empty() */
477 #define blk_queued_rq(rq) (!list_empty(&(rq)->queuelist))
479 #define list_entry_rq(ptr) list_entry((ptr), struct request, queuelist)
481 #define rq_data_dir(rq) ((rq)->cmd_flags & 1)
484 * We regard a request as sync, if it's a READ or a SYNC write.
486 #define rq_is_sync(rq) (rq_data_dir((rq)) == READ || (rq)->cmd_flags & REQ_RW_SYNC)
487 #define rq_is_meta(rq) ((rq)->cmd_flags & REQ_RW_META)
489 static inline int blk_queue_full(struct request_queue
*q
, int rw
)
492 return test_bit(QUEUE_FLAG_READFULL
, &q
->queue_flags
);
493 return test_bit(QUEUE_FLAG_WRITEFULL
, &q
->queue_flags
);
496 static inline void blk_set_queue_full(struct request_queue
*q
, int rw
)
499 set_bit(QUEUE_FLAG_READFULL
, &q
->queue_flags
);
501 set_bit(QUEUE_FLAG_WRITEFULL
, &q
->queue_flags
);
504 static inline void blk_clear_queue_full(struct request_queue
*q
, int rw
)
507 clear_bit(QUEUE_FLAG_READFULL
, &q
->queue_flags
);
509 clear_bit(QUEUE_FLAG_WRITEFULL
, &q
->queue_flags
);
514 * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
515 * it already be started by driver.
517 #define RQ_NOMERGE_FLAGS \
518 (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER)
519 #define rq_mergeable(rq) \
520 (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && blk_fs_request((rq)))
523 * q->prep_rq_fn return values
525 #define BLKPREP_OK 0 /* serve it */
526 #define BLKPREP_KILL 1 /* fatal error, kill */
527 #define BLKPREP_DEFER 2 /* leave on queue */
529 extern unsigned long blk_max_low_pfn
, blk_max_pfn
;
532 * standard bounce addresses:
534 * BLK_BOUNCE_HIGH : bounce all highmem pages
535 * BLK_BOUNCE_ANY : don't bounce anything
536 * BLK_BOUNCE_ISA : bounce pages above ISA DMA boundary
539 #if BITS_PER_LONG == 32
540 #define BLK_BOUNCE_HIGH ((u64)blk_max_low_pfn << PAGE_SHIFT)
542 #define BLK_BOUNCE_HIGH -1ULL
544 #define BLK_BOUNCE_ANY (-1ULL)
545 #define BLK_BOUNCE_ISA (ISA_DMA_THRESHOLD)
548 * default timeout for SG_IO if none specified
550 #define BLK_DEFAULT_SG_TIMEOUT (60 * HZ)
553 extern int init_emergency_isa_pool(void);
554 extern void blk_queue_bounce(struct request_queue
*q
, struct bio
**bio
);
556 static inline int init_emergency_isa_pool(void)
560 static inline void blk_queue_bounce(struct request_queue
*q
, struct bio
**bio
)
563 #endif /* CONFIG_MMU */
565 struct req_iterator
{
570 /* This should not be used directly - use rq_for_each_segment */
571 #define __rq_for_each_bio(_bio, rq) \
573 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
575 #define rq_for_each_segment(bvl, _rq, _iter) \
576 __rq_for_each_bio(_iter.bio, _rq) \
577 bio_for_each_segment(bvl, _iter.bio, _iter.i)
579 #define rq_iter_last(rq, _iter) \
580 (_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)
582 extern int blk_register_queue(struct gendisk
*disk
);
583 extern void blk_unregister_queue(struct gendisk
*disk
);
584 extern void register_disk(struct gendisk
*dev
);
585 extern void generic_make_request(struct bio
*bio
);
586 extern void blk_put_request(struct request
*);
587 extern void __blk_put_request(struct request_queue
*, struct request
*);
588 extern void blk_end_sync_rq(struct request
*rq
, int error
);
589 extern struct request
*blk_get_request(struct request_queue
*, int, gfp_t
);
590 extern void blk_insert_request(struct request_queue
*, struct request
*, int, void *);
591 extern void blk_requeue_request(struct request_queue
*, struct request
*);
592 extern void blk_plug_device(struct request_queue
*);
593 extern int blk_remove_plug(struct request_queue
*);
594 extern void blk_recount_segments(struct request_queue
*, struct bio
*);
595 extern int scsi_cmd_ioctl(struct file
*, struct request_queue
*,
596 struct gendisk
*, unsigned int, void __user
*);
597 extern int sg_scsi_ioctl(struct file
*, struct request_queue
*,
598 struct gendisk
*, struct scsi_ioctl_command __user
*);
601 * Temporary export, until SCSI gets fixed up.
603 extern int blk_rq_append_bio(struct request_queue
*q
, struct request
*rq
,
607 * A queue has just exitted congestion. Note this in the global counter of
608 * congested queues, and wake up anyone who was waiting for requests to be
611 static inline void blk_clear_queue_congested(struct request_queue
*q
, int rw
)
613 clear_bdi_congested(&q
->backing_dev_info
, rw
);
617 * A queue has just entered congestion. Flag that in the queue's VM-visible
618 * state flags and increment the global gounter of congested queues.
620 static inline void blk_set_queue_congested(struct request_queue
*q
, int rw
)
622 set_bdi_congested(&q
->backing_dev_info
, rw
);
625 extern void blk_start_queue(struct request_queue
*q
);
626 extern void blk_stop_queue(struct request_queue
*q
);
627 extern void blk_sync_queue(struct request_queue
*q
);
628 extern void __blk_stop_queue(struct request_queue
*q
);
629 extern void blk_run_queue(struct request_queue
*);
630 extern void blk_start_queueing(struct request_queue
*);
631 extern int blk_rq_map_user(struct request_queue
*, struct request
*, void __user
*, unsigned long);
632 extern int blk_rq_unmap_user(struct bio
*);
633 extern int blk_rq_map_kern(struct request_queue
*, struct request
*, void *, unsigned int, gfp_t
);
634 extern int blk_rq_map_user_iov(struct request_queue
*, struct request
*,
635 struct sg_iovec
*, int, unsigned int);
636 extern int blk_execute_rq(struct request_queue
*, struct gendisk
*,
637 struct request
*, int);
638 extern void blk_execute_rq_nowait(struct request_queue
*, struct gendisk
*,
639 struct request
*, int, rq_end_io_fn
*);
640 extern int blk_verify_command(unsigned char *, int);
641 extern void blk_unplug(struct request_queue
*q
);
643 static inline struct request_queue
*bdev_get_queue(struct block_device
*bdev
)
645 return bdev
->bd_disk
->queue
;
648 static inline void blk_run_backing_dev(struct backing_dev_info
*bdi
,
651 if (bdi
&& bdi
->unplug_io_fn
)
652 bdi
->unplug_io_fn(bdi
, page
);
655 static inline void blk_run_address_space(struct address_space
*mapping
)
658 blk_run_backing_dev(mapping
->backing_dev_info
, NULL
);
662 * blk_end_request() and friends.
663 * __blk_end_request() and end_request() must be called with
664 * the request queue spinlock acquired.
666 * Several drivers define their own end_request and call
667 * blk_end_request() for parts of the original function.
668 * This prevents code duplication in drivers.
670 extern int blk_end_request(struct request
*rq
, int error
,
671 unsigned int nr_bytes
);
672 extern int __blk_end_request(struct request
*rq
, int error
,
673 unsigned int nr_bytes
);
674 extern int blk_end_bidi_request(struct request
*rq
, int error
,
675 unsigned int nr_bytes
, unsigned int bidi_bytes
);
676 extern void end_request(struct request
*, int);
677 extern void end_queued_request(struct request
*, int);
678 extern void end_dequeued_request(struct request
*, int);
679 extern int blk_end_request_callback(struct request
*rq
, int error
,
680 unsigned int nr_bytes
,
681 int (drv_callback
)(struct request
*));
682 extern void blk_complete_request(struct request
*);
685 * blk_end_request() takes bytes instead of sectors as a complete size.
686 * blk_rq_bytes() returns bytes left to complete in the entire request.
687 * blk_rq_cur_bytes() returns bytes left to complete in the current segment.
689 extern unsigned int blk_rq_bytes(struct request
*rq
);
690 extern unsigned int blk_rq_cur_bytes(struct request
*rq
);
692 static inline void blkdev_dequeue_request(struct request
*req
)
694 elv_dequeue_request(req
->q
, req
);
698 * Access functions for manipulating queue properties
700 extern struct request_queue
*blk_init_queue_node(request_fn_proc
*rfn
,
701 spinlock_t
*lock
, int node_id
);
702 extern struct request_queue
*blk_init_queue(request_fn_proc
*, spinlock_t
*);
703 extern void blk_cleanup_queue(struct request_queue
*);
704 extern void blk_queue_make_request(struct request_queue
*, make_request_fn
*);
705 extern void blk_queue_bounce_limit(struct request_queue
*, u64
);
706 extern void blk_queue_max_sectors(struct request_queue
*, unsigned int);
707 extern void blk_queue_max_phys_segments(struct request_queue
*, unsigned short);
708 extern void blk_queue_max_hw_segments(struct request_queue
*, unsigned short);
709 extern void blk_queue_max_segment_size(struct request_queue
*, unsigned int);
710 extern void blk_queue_hardsect_size(struct request_queue
*, unsigned short);
711 extern void blk_queue_stack_limits(struct request_queue
*t
, struct request_queue
*b
);
712 extern void blk_queue_dma_pad(struct request_queue
*, unsigned int);
713 extern int blk_queue_dma_drain(struct request_queue
*q
,
714 dma_drain_needed_fn
*dma_drain_needed
,
715 void *buf
, unsigned int size
);
716 extern void blk_queue_segment_boundary(struct request_queue
*, unsigned long);
717 extern void blk_queue_prep_rq(struct request_queue
*, prep_rq_fn
*pfn
);
718 extern void blk_queue_merge_bvec(struct request_queue
*, merge_bvec_fn
*);
719 extern void blk_queue_dma_alignment(struct request_queue
*, int);
720 extern void blk_queue_update_dma_alignment(struct request_queue
*, int);
721 extern void blk_queue_softirq_done(struct request_queue
*, softirq_done_fn
*);
722 extern struct backing_dev_info
*blk_get_backing_dev_info(struct block_device
*bdev
);
723 extern int blk_queue_ordered(struct request_queue
*, unsigned, prepare_flush_fn
*);
724 extern int blk_do_ordered(struct request_queue
*, struct request
**);
725 extern unsigned blk_ordered_cur_seq(struct request_queue
*);
726 extern unsigned blk_ordered_req_seq(struct request
*);
727 extern void blk_ordered_complete_seq(struct request_queue
*, unsigned, int);
729 extern int blk_rq_map_sg(struct request_queue
*, struct request
*, struct scatterlist
*);
730 extern void blk_dump_rq_flags(struct request
*, char *);
731 extern void generic_unplug_device(struct request_queue
*);
732 extern void __generic_unplug_device(struct request_queue
*);
733 extern long nr_blockdev_pages(void);
735 int blk_get_queue(struct request_queue
*);
736 struct request_queue
*blk_alloc_queue(gfp_t
);
737 struct request_queue
*blk_alloc_queue_node(gfp_t
, int);
738 extern void blk_put_queue(struct request_queue
*);
743 #define blk_queue_tag_depth(q) ((q)->queue_tags->busy)
744 #define blk_queue_tag_queue(q) ((q)->queue_tags->busy < (q)->queue_tags->max_depth)
745 #define blk_rq_tagged(rq) ((rq)->cmd_flags & REQ_QUEUED)
746 extern int blk_queue_start_tag(struct request_queue
*, struct request
*);
747 extern struct request
*blk_queue_find_tag(struct request_queue
*, int);
748 extern void blk_queue_end_tag(struct request_queue
*, struct request
*);
749 extern int blk_queue_init_tags(struct request_queue
*, int, struct blk_queue_tag
*);
750 extern void blk_queue_free_tags(struct request_queue
*);
751 extern int blk_queue_resize_tags(struct request_queue
*, int);
752 extern void blk_queue_invalidate_tags(struct request_queue
*);
753 extern struct blk_queue_tag
*blk_init_tags(int);
754 extern void blk_free_tags(struct blk_queue_tag
*);
756 static inline struct request
*blk_map_queue_find_tag(struct blk_queue_tag
*bqt
,
759 if (unlikely(bqt
== NULL
|| tag
>= bqt
->real_max_depth
))
761 return bqt
->tag_index
[tag
];
764 extern int blkdev_issue_flush(struct block_device
*, sector_t
*);
766 #define MAX_PHYS_SEGMENTS 128
767 #define MAX_HW_SEGMENTS 128
768 #define SAFE_MAX_SECTORS 255
769 #define BLK_DEF_MAX_SECTORS 1024
771 #define MAX_SEGMENT_SIZE 65536
773 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
775 static inline int queue_hardsect_size(struct request_queue
*q
)
779 if (q
&& q
->hardsect_size
)
780 retval
= q
->hardsect_size
;
785 static inline int bdev_hardsect_size(struct block_device
*bdev
)
787 return queue_hardsect_size(bdev_get_queue(bdev
));
790 static inline int queue_dma_alignment(struct request_queue
*q
)
792 return q
? q
->dma_alignment
: 511;
795 /* assumes size > 256 */
796 static inline unsigned int blksize_bits(unsigned int size
)
798 unsigned int bits
= 8;
802 } while (size
> 256);
806 static inline unsigned int block_size(struct block_device
*bdev
)
808 return bdev
->bd_block_size
;
811 typedef struct {struct page
*v
;} Sector
;
813 unsigned char *read_dev_sector(struct block_device
*, sector_t
, Sector
*);
815 static inline void put_dev_sector(Sector p
)
817 page_cache_release(p
.v
);
821 int kblockd_schedule_work(struct work_struct
*work
);
822 void kblockd_flush_work(struct work_struct
*work
);
824 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
825 MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
826 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
827 MODULE_ALIAS("block-major-" __stringify(major) "-*")
830 #else /* CONFIG_BLOCK */
832 * stubs for when the block layer is configured out
834 #define buffer_heads_over_limit 0
836 static inline long nr_blockdev_pages(void)
841 static inline void exit_io_context(void)
846 static inline int put_io_context(struct io_context
*ioc
)
852 #endif /* CONFIG_BLOCK */