1 #ifndef _LINUX_BLKDEV_H
2 #define _LINUX_BLKDEV_H
4 #include <linux/sched.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>
17 #include <linux/bsg.h>
19 #include <asm/scatterlist.h>
22 # include <asm/div64.h>
23 # define sector_div(a, b) do_div(a, b)
25 # define sector_div(n, b)( \
37 struct scsi_ioctl_command
;
40 struct elevator_queue
;
41 typedef struct elevator_queue elevator_t
;
42 struct request_pm_state
;
47 #define BLKDEV_MIN_RQ 4
48 #define BLKDEV_MAX_RQ 128 /* Default maximum */
51 * This is the per-process anticipatory I/O scheduler state.
53 struct as_io_context
{
56 void (*dtor
)(struct as_io_context
*aic
); /* destructor */
57 void (*exit
)(struct as_io_context
*aic
); /* called on task exit */
60 atomic_t nr_queued
; /* queued reads & sync writes */
61 atomic_t nr_dispatched
; /* number of requests gone to the drivers */
63 /* IO History tracking */
65 unsigned long last_end_request
;
66 unsigned long ttime_total
;
67 unsigned long ttime_samples
;
68 unsigned long ttime_mean
;
70 unsigned int seek_samples
;
71 sector_t last_request_pos
;
77 struct cfq_io_context
{
78 struct rb_node rb_node
;
81 struct cfq_queue
*cfqq
[2];
83 struct io_context
*ioc
;
85 unsigned long last_end_request
;
86 sector_t last_request_pos
;
88 unsigned long ttime_total
;
89 unsigned long ttime_samples
;
90 unsigned long ttime_mean
;
92 unsigned int seek_samples
;
96 struct list_head queue_list
;
98 void (*dtor
)(struct io_context
*); /* destructor */
99 void (*exit
)(struct io_context
*); /* called on task exit */
103 * This is the per-process I/O subsystem state. It is refcounted and
104 * kmalloc'ed. Currently all fields are modified in process io context
105 * (apart from the atomic refcount), so require no locking.
109 struct task_struct
*task
;
111 unsigned int ioprio_changed
;
114 * For request batching
116 unsigned long last_waited
; /* Time last woken after wait for request */
117 int nr_batch_requests
; /* Number of requests left in the batch */
119 struct as_io_context
*aic
;
120 struct rb_root cic_root
;
124 void put_io_context(struct io_context
*ioc
);
125 void exit_io_context(void);
126 struct io_context
*get_io_context(gfp_t gfp_flags
, int node
);
127 void copy_io_context(struct io_context
**pdst
, struct io_context
**psrc
);
128 void swap_io_context(struct io_context
**ioc1
, struct io_context
**ioc2
);
131 typedef void (rq_end_io_fn
)(struct request
*, int);
133 struct request_list
{
138 wait_queue_head_t wait
[2];
142 * request command types
144 enum rq_cmd_type_bits
{
145 REQ_TYPE_FS
= 1, /* fs request */
146 REQ_TYPE_BLOCK_PC
, /* scsi command */
147 REQ_TYPE_SENSE
, /* sense request */
148 REQ_TYPE_PM_SUSPEND
, /* suspend request */
149 REQ_TYPE_PM_RESUME
, /* resume request */
150 REQ_TYPE_PM_SHUTDOWN
, /* shutdown request */
151 REQ_TYPE_FLUSH
, /* flush request */
152 REQ_TYPE_SPECIAL
, /* driver defined type */
153 REQ_TYPE_LINUX_BLOCK
, /* generic block layer message */
155 * for ATA/ATAPI devices. this really doesn't belong here, ide should
156 * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver
157 * private REQ_LB opcodes to differentiate what type of request this is
161 REQ_TYPE_ATA_TASKFILE
,
166 * For request of type REQ_TYPE_LINUX_BLOCK, rq->cmd[0] is the opcode being
167 * sent down (similar to how REQ_TYPE_BLOCK_PC means that ->cmd[] holds a
170 * 0x00 -> 0x3f are driver private, to be used for whatever purpose they need,
171 * typically to differentiate REQ_TYPE_SPECIAL requests.
176 * just examples for now
178 REQ_LB_OP_EJECT
= 0x40, /* eject request */
179 REQ_LB_OP_FLUSH
= 0x41, /* flush device */
183 * request type modified bits. first three bits match BIO_RW* bits, important
186 __REQ_RW
, /* not set, read. set, write */
187 __REQ_FAILFAST
, /* no low level driver retries */
188 __REQ_SORTED
, /* elevator knows about this request */
189 __REQ_SOFTBARRIER
, /* may not be passed by ioscheduler */
190 __REQ_HARDBARRIER
, /* may not be passed by drive either */
191 __REQ_FUA
, /* forced unit access */
192 __REQ_NOMERGE
, /* don't touch this for merging */
193 __REQ_STARTED
, /* drive already may have started this one */
194 __REQ_DONTPREP
, /* don't call prep for this one */
195 __REQ_QUEUED
, /* uses queueing */
196 __REQ_ELVPRIV
, /* elevator private data attached */
197 __REQ_FAILED
, /* set if the request failed */
198 __REQ_QUIET
, /* don't worry about errors */
199 __REQ_PREEMPT
, /* set for "ide_preempt" requests */
200 __REQ_ORDERED_COLOR
, /* is before or after barrier */
201 __REQ_RW_SYNC
, /* request is sync (O_DIRECT) */
202 __REQ_ALLOCED
, /* request came from our alloc pool */
203 __REQ_RW_META
, /* metadata io request */
204 __REQ_NR_BITS
, /* stops here */
207 #define REQ_RW (1 << __REQ_RW)
208 #define REQ_FAILFAST (1 << __REQ_FAILFAST)
209 #define REQ_SORTED (1 << __REQ_SORTED)
210 #define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER)
211 #define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER)
212 #define REQ_FUA (1 << __REQ_FUA)
213 #define REQ_NOMERGE (1 << __REQ_NOMERGE)
214 #define REQ_STARTED (1 << __REQ_STARTED)
215 #define REQ_DONTPREP (1 << __REQ_DONTPREP)
216 #define REQ_QUEUED (1 << __REQ_QUEUED)
217 #define REQ_ELVPRIV (1 << __REQ_ELVPRIV)
218 #define REQ_FAILED (1 << __REQ_FAILED)
219 #define REQ_QUIET (1 << __REQ_QUIET)
220 #define REQ_PREEMPT (1 << __REQ_PREEMPT)
221 #define REQ_ORDERED_COLOR (1 << __REQ_ORDERED_COLOR)
222 #define REQ_RW_SYNC (1 << __REQ_RW_SYNC)
223 #define REQ_ALLOCED (1 << __REQ_ALLOCED)
224 #define REQ_RW_META (1 << __REQ_RW_META)
226 #define BLK_MAX_CDB 16
229 * try to put the fields that are referenced together in the same cacheline
232 struct list_head queuelist
;
233 struct list_head donelist
;
235 struct request_queue
*q
;
237 unsigned int cmd_flags
;
238 enum rq_cmd_type_bits cmd_type
;
240 /* Maintain bio traversal state for part by part I/O submission.
241 * hard_* are block layer internals, no driver should touch them!
244 sector_t sector
; /* next sector to submit */
245 sector_t hard_sector
; /* next sector to complete */
246 unsigned long nr_sectors
; /* no. of sectors left to submit */
247 unsigned long hard_nr_sectors
; /* no. of sectors left to complete */
248 /* no. of sectors left to submit in the current segment */
249 unsigned int current_nr_sectors
;
251 /* no. of sectors left to complete in the current segment */
252 unsigned int hard_cur_sectors
;
257 struct hlist_node hash
; /* merge hash */
259 * The rb_node is only used inside the io scheduler, requests
260 * are pruned when moved to the dispatch queue. So let the
261 * completion_data share space with the rb_node.
264 struct rb_node rb_node
; /* sort/lookup */
265 void *completion_data
;
269 * two pointers are available for the IO schedulers, if they need
270 * more they have to dynamically allocate it.
272 void *elevator_private
;
273 void *elevator_private2
;
275 struct gendisk
*rq_disk
;
276 unsigned long start_time
;
278 /* Number of scatter-gather DMA addr+len pairs after
279 * physical address coalescing is performed.
281 unsigned short nr_phys_segments
;
283 /* Number of scatter-gather addr+len pairs after
284 * physical and DMA remapping hardware coalescing is performed.
285 * This is the number of scatter-gather entries the driver
286 * will actually have to deal with after DMA mapping is done.
288 unsigned short nr_hw_segments
;
290 unsigned short ioprio
;
301 * when request is used as a packet command carrier
303 unsigned int cmd_len
;
304 unsigned char cmd
[BLK_MAX_CDB
];
306 unsigned int data_len
;
307 unsigned int sense_len
;
311 unsigned int timeout
;
315 * completion callback.
317 rq_end_io_fn
*end_io
;
321 struct request
*next_rq
;
325 * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
326 * requests. Some step values could eventually be made generic.
328 struct request_pm_state
330 /* PM state machine step value, currently driver specific */
332 /* requested PM state value (S1, S2, S3, S4, ...) */
334 void* data
; /* for driver use */
337 #include <linux/elevator.h>
339 typedef void (request_fn_proc
) (struct request_queue
*q
);
340 typedef int (make_request_fn
) (struct request_queue
*q
, struct bio
*bio
);
341 typedef int (prep_rq_fn
) (struct request_queue
*, struct request
*);
342 typedef void (unplug_fn
) (struct request_queue
*);
345 typedef int (merge_bvec_fn
) (struct request_queue
*, struct bio
*, struct bio_vec
*);
346 typedef int (issue_flush_fn
) (struct request_queue
*, struct gendisk
*, sector_t
*);
347 typedef void (prepare_flush_fn
) (struct request_queue
*, struct request
*);
348 typedef void (softirq_done_fn
)(struct request
*);
350 enum blk_queue_state
{
355 struct blk_queue_tag
{
356 struct request
**tag_index
; /* map of busy tags */
357 unsigned long *tag_map
; /* bit map of free/busy tags */
358 struct list_head busy_list
; /* fifo list of busy tags */
359 int busy
; /* current depth */
360 int max_depth
; /* what we will send to device */
361 int real_max_depth
; /* what the array can hold */
362 atomic_t refcnt
; /* map can be shared */
368 * Together with queue_head for cacheline sharing
370 struct list_head queue_head
;
371 struct request
*last_merge
;
372 elevator_t
*elevator
;
375 * the queue request freelist, one for reads and one for writes
377 struct request_list rq
;
379 request_fn_proc
*request_fn
;
380 make_request_fn
*make_request_fn
;
381 prep_rq_fn
*prep_rq_fn
;
382 unplug_fn
*unplug_fn
;
383 merge_bvec_fn
*merge_bvec_fn
;
384 issue_flush_fn
*issue_flush_fn
;
385 prepare_flush_fn
*prepare_flush_fn
;
386 softirq_done_fn
*softirq_done_fn
;
389 * Dispatch queue sorting
392 struct request
*boundary_rq
;
395 * Auto-unplugging state
397 struct timer_list unplug_timer
;
398 int unplug_thresh
; /* After this many requests */
399 unsigned long unplug_delay
; /* After this many jiffies */
400 struct work_struct unplug_work
;
402 struct backing_dev_info backing_dev_info
;
405 * The queue owner gets to use this for whatever they like.
406 * ll_rw_blk doesn't touch it.
411 * queue needs bounce pages for pages above this limit
413 unsigned long bounce_pfn
;
417 * various queue flags, see QUEUE_* below
419 unsigned long queue_flags
;
422 * protects queue structures from reentrancy. ->__queue_lock should
423 * _never_ be used directly, it is queue private. always use
426 spinlock_t __queue_lock
;
427 spinlock_t
*queue_lock
;
437 unsigned long nr_requests
; /* Max # of requests */
438 unsigned int nr_congestion_on
;
439 unsigned int nr_congestion_off
;
440 unsigned int nr_batching
;
442 unsigned int max_sectors
;
443 unsigned int max_hw_sectors
;
444 unsigned short max_phys_segments
;
445 unsigned short max_hw_segments
;
446 unsigned short hardsect_size
;
447 unsigned int max_segment_size
;
449 unsigned long seg_boundary_mask
;
450 unsigned int dma_alignment
;
452 struct blk_queue_tag
*queue_tags
;
454 unsigned int nr_sorted
;
455 unsigned int in_flight
;
460 unsigned int sg_timeout
;
461 unsigned int sg_reserved_size
;
463 #ifdef CONFIG_BLK_DEV_IO_TRACE
464 struct blk_trace
*blk_trace
;
467 * reserved for flush operations
469 unsigned int ordered
, next_ordered
, ordseq
;
470 int orderr
, ordcolor
;
471 struct request pre_flush_rq
, bar_rq
, post_flush_rq
;
472 struct request
*orig_bar_rq
;
473 unsigned int bi_size
;
475 struct mutex sysfs_lock
;
477 #if defined(CONFIG_BLK_DEV_BSG)
478 struct bsg_class_device bsg_dev
;
482 #define QUEUE_FLAG_CLUSTER 0 /* cluster several segments into 1 */
483 #define QUEUE_FLAG_QUEUED 1 /* uses generic tag queueing */
484 #define QUEUE_FLAG_STOPPED 2 /* queue is stopped */
485 #define QUEUE_FLAG_READFULL 3 /* write queue has been filled */
486 #define QUEUE_FLAG_WRITEFULL 4 /* read queue has been filled */
487 #define QUEUE_FLAG_DEAD 5 /* queue being torn down */
488 #define QUEUE_FLAG_REENTER 6 /* Re-entrancy avoidance */
489 #define QUEUE_FLAG_PLUGGED 7 /* queue is plugged */
490 #define QUEUE_FLAG_ELVSWITCH 8 /* don't use elevator, just do FIFO */
491 #define QUEUE_FLAG_BIDI 9 /* queue supports bidi requests */
495 * Hardbarrier is supported with one of the following methods.
497 * NONE : hardbarrier unsupported
498 * DRAIN : ordering by draining is enough
499 * DRAIN_FLUSH : ordering by draining w/ pre and post flushes
500 * DRAIN_FUA : ordering by draining w/ pre flush and FUA write
501 * TAG : ordering by tag is enough
502 * TAG_FLUSH : ordering by tag w/ pre and post flushes
503 * TAG_FUA : ordering by tag w/ pre flush and FUA write
505 QUEUE_ORDERED_NONE
= 0x00,
506 QUEUE_ORDERED_DRAIN
= 0x01,
507 QUEUE_ORDERED_TAG
= 0x02,
509 QUEUE_ORDERED_PREFLUSH
= 0x10,
510 QUEUE_ORDERED_POSTFLUSH
= 0x20,
511 QUEUE_ORDERED_FUA
= 0x40,
513 QUEUE_ORDERED_DRAIN_FLUSH
= QUEUE_ORDERED_DRAIN
|
514 QUEUE_ORDERED_PREFLUSH
| QUEUE_ORDERED_POSTFLUSH
,
515 QUEUE_ORDERED_DRAIN_FUA
= QUEUE_ORDERED_DRAIN
|
516 QUEUE_ORDERED_PREFLUSH
| QUEUE_ORDERED_FUA
,
517 QUEUE_ORDERED_TAG_FLUSH
= QUEUE_ORDERED_TAG
|
518 QUEUE_ORDERED_PREFLUSH
| QUEUE_ORDERED_POSTFLUSH
,
519 QUEUE_ORDERED_TAG_FUA
= QUEUE_ORDERED_TAG
|
520 QUEUE_ORDERED_PREFLUSH
| QUEUE_ORDERED_FUA
,
523 * Ordered operation sequence
525 QUEUE_ORDSEQ_STARTED
= 0x01, /* flushing in progress */
526 QUEUE_ORDSEQ_DRAIN
= 0x02, /* waiting for the queue to be drained */
527 QUEUE_ORDSEQ_PREFLUSH
= 0x04, /* pre-flushing in progress */
528 QUEUE_ORDSEQ_BAR
= 0x08, /* original barrier req in progress */
529 QUEUE_ORDSEQ_POSTFLUSH
= 0x10, /* post-flushing in progress */
530 QUEUE_ORDSEQ_DONE
= 0x20,
533 #define blk_queue_plugged(q) test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
534 #define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
535 #define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
536 #define blk_queue_flushing(q) ((q)->ordseq)
538 #define blk_fs_request(rq) ((rq)->cmd_type == REQ_TYPE_FS)
539 #define blk_pc_request(rq) ((rq)->cmd_type == REQ_TYPE_BLOCK_PC)
540 #define blk_special_request(rq) ((rq)->cmd_type == REQ_TYPE_SPECIAL)
541 #define blk_sense_request(rq) ((rq)->cmd_type == REQ_TYPE_SENSE)
543 #define blk_noretry_request(rq) ((rq)->cmd_flags & REQ_FAILFAST)
544 #define blk_rq_started(rq) ((rq)->cmd_flags & REQ_STARTED)
546 #define blk_account_rq(rq) (blk_rq_started(rq) && blk_fs_request(rq))
548 #define blk_pm_suspend_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND)
549 #define blk_pm_resume_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_RESUME)
550 #define blk_pm_request(rq) \
551 (blk_pm_suspend_request(rq) || blk_pm_resume_request(rq))
553 #define blk_sorted_rq(rq) ((rq)->cmd_flags & REQ_SORTED)
554 #define blk_barrier_rq(rq) ((rq)->cmd_flags & REQ_HARDBARRIER)
555 #define blk_fua_rq(rq) ((rq)->cmd_flags & REQ_FUA)
556 #define blk_bidi_rq(rq) ((rq)->next_rq != NULL)
558 #define list_entry_rq(ptr) list_entry((ptr), struct request, queuelist)
560 #define rq_data_dir(rq) ((rq)->cmd_flags & 1)
563 * We regard a request as sync, if it's a READ or a SYNC write.
565 #define rq_is_sync(rq) (rq_data_dir((rq)) == READ || (rq)->cmd_flags & REQ_RW_SYNC)
566 #define rq_is_meta(rq) ((rq)->cmd_flags & REQ_RW_META)
568 static inline int blk_queue_full(struct request_queue
*q
, int rw
)
571 return test_bit(QUEUE_FLAG_READFULL
, &q
->queue_flags
);
572 return test_bit(QUEUE_FLAG_WRITEFULL
, &q
->queue_flags
);
575 static inline void blk_set_queue_full(struct request_queue
*q
, int rw
)
578 set_bit(QUEUE_FLAG_READFULL
, &q
->queue_flags
);
580 set_bit(QUEUE_FLAG_WRITEFULL
, &q
->queue_flags
);
583 static inline void blk_clear_queue_full(struct request_queue
*q
, int rw
)
586 clear_bit(QUEUE_FLAG_READFULL
, &q
->queue_flags
);
588 clear_bit(QUEUE_FLAG_WRITEFULL
, &q
->queue_flags
);
593 * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
594 * it already be started by driver.
596 #define RQ_NOMERGE_FLAGS \
597 (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER)
598 #define rq_mergeable(rq) \
599 (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && blk_fs_request((rq)))
602 * q->prep_rq_fn return values
604 #define BLKPREP_OK 0 /* serve it */
605 #define BLKPREP_KILL 1 /* fatal error, kill */
606 #define BLKPREP_DEFER 2 /* leave on queue */
608 extern unsigned long blk_max_low_pfn
, blk_max_pfn
;
611 * standard bounce addresses:
613 * BLK_BOUNCE_HIGH : bounce all highmem pages
614 * BLK_BOUNCE_ANY : don't bounce anything
615 * BLK_BOUNCE_ISA : bounce pages above ISA DMA boundary
617 #define BLK_BOUNCE_HIGH ((u64)blk_max_low_pfn << PAGE_SHIFT)
618 #define BLK_BOUNCE_ANY ((u64)blk_max_pfn << PAGE_SHIFT)
619 #define BLK_BOUNCE_ISA (ISA_DMA_THRESHOLD)
622 * default timeout for SG_IO if none specified
624 #define BLK_DEFAULT_SG_TIMEOUT (60 * HZ)
627 extern int init_emergency_isa_pool(void);
628 extern void blk_queue_bounce(struct request_queue
*q
, struct bio
**bio
);
630 static inline int init_emergency_isa_pool(void)
634 static inline void blk_queue_bounce(struct request_queue
*q
, struct bio
**bio
)
637 #endif /* CONFIG_MMU */
639 #define rq_for_each_bio(_bio, rq) \
641 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
643 extern int blk_register_queue(struct gendisk
*disk
);
644 extern void blk_unregister_queue(struct gendisk
*disk
);
645 extern void register_disk(struct gendisk
*dev
);
646 extern void generic_make_request(struct bio
*bio
);
647 extern void blk_put_request(struct request
*);
648 extern void __blk_put_request(struct request_queue
*, struct request
*);
649 extern void blk_end_sync_rq(struct request
*rq
, int error
);
650 extern struct request
*blk_get_request(struct request_queue
*, int, gfp_t
);
651 extern void blk_insert_request(struct request_queue
*, struct request
*, int, void *);
652 extern void blk_requeue_request(struct request_queue
*, struct request
*);
653 extern void blk_plug_device(struct request_queue
*);
654 extern int blk_remove_plug(struct request_queue
*);
655 extern void blk_recount_segments(struct request_queue
*, struct bio
*);
656 extern int scsi_cmd_ioctl(struct file
*, struct request_queue
*,
657 struct gendisk
*, unsigned int, void __user
*);
658 extern int sg_scsi_ioctl(struct file
*, struct request_queue
*,
659 struct gendisk
*, struct scsi_ioctl_command __user
*);
662 * Temporary export, until SCSI gets fixed up.
664 extern int ll_back_merge_fn(struct request_queue
*, struct request
*,
668 * A queue has just exitted congestion. Note this in the global counter of
669 * congested queues, and wake up anyone who was waiting for requests to be
672 static inline void blk_clear_queue_congested(struct request_queue
*q
, int rw
)
674 clear_bdi_congested(&q
->backing_dev_info
, rw
);
678 * A queue has just entered congestion. Flag that in the queue's VM-visible
679 * state flags and increment the global gounter of congested queues.
681 static inline void blk_set_queue_congested(struct request_queue
*q
, int rw
)
683 set_bdi_congested(&q
->backing_dev_info
, rw
);
686 extern void blk_start_queue(struct request_queue
*q
);
687 extern void blk_stop_queue(struct request_queue
*q
);
688 extern void blk_sync_queue(struct request_queue
*q
);
689 extern void __blk_stop_queue(struct request_queue
*q
);
690 extern void blk_run_queue(struct request_queue
*);
691 extern void blk_start_queueing(struct request_queue
*);
692 extern int blk_rq_map_user(struct request_queue
*, struct request
*, void __user
*, unsigned long);
693 extern int blk_rq_unmap_user(struct bio
*);
694 extern int blk_rq_map_kern(struct request_queue
*, struct request
*, void *, unsigned int, gfp_t
);
695 extern int blk_rq_map_user_iov(struct request_queue
*, struct request
*,
696 struct sg_iovec
*, int, unsigned int);
697 extern int blk_execute_rq(struct request_queue
*, struct gendisk
*,
698 struct request
*, int);
699 extern void blk_execute_rq_nowait(struct request_queue
*, struct gendisk
*,
700 struct request
*, int, rq_end_io_fn
*);
701 extern int blk_verify_command(unsigned char *, int);
703 static inline struct request_queue
*bdev_get_queue(struct block_device
*bdev
)
705 return bdev
->bd_disk
->queue
;
708 static inline void blk_run_backing_dev(struct backing_dev_info
*bdi
,
711 if (bdi
&& bdi
->unplug_io_fn
)
712 bdi
->unplug_io_fn(bdi
, page
);
715 static inline void blk_run_address_space(struct address_space
*mapping
)
718 blk_run_backing_dev(mapping
->backing_dev_info
, NULL
);
722 * end_request() and friends. Must be called with the request queue spinlock
723 * acquired. All functions called within end_request() _must_be_ atomic.
725 * Several drivers define their own end_request and call
726 * end_that_request_first() and end_that_request_last()
727 * for parts of the original function. This prevents
728 * code duplication in drivers.
730 extern int end_that_request_first(struct request
*, int, int);
731 extern int end_that_request_chunk(struct request
*, int, int);
732 extern void end_that_request_last(struct request
*, int);
733 extern void end_request(struct request
*req
, int uptodate
);
734 extern void blk_complete_request(struct request
*);
737 * end_that_request_first/chunk() takes an uptodate argument. we account
738 * any value <= as an io error. 0 means -EIO for compatability reasons,
739 * any other < 0 value is the direct error type. An uptodate value of
740 * 1 indicates successful io completion
742 #define end_io_error(uptodate) (unlikely((uptodate) <= 0))
744 static inline void blkdev_dequeue_request(struct request
*req
)
746 elv_dequeue_request(req
->q
, req
);
750 * Access functions for manipulating queue properties
752 extern struct request_queue
*blk_init_queue_node(request_fn_proc
*rfn
,
753 spinlock_t
*lock
, int node_id
);
754 extern struct request_queue
*blk_init_queue(request_fn_proc
*, spinlock_t
*);
755 extern void blk_cleanup_queue(struct request_queue
*);
756 extern void blk_queue_make_request(struct request_queue
*, make_request_fn
*);
757 extern void blk_queue_bounce_limit(struct request_queue
*, u64
);
758 extern void blk_queue_max_sectors(struct request_queue
*, unsigned int);
759 extern void blk_queue_max_phys_segments(struct request_queue
*, unsigned short);
760 extern void blk_queue_max_hw_segments(struct request_queue
*, unsigned short);
761 extern void blk_queue_max_segment_size(struct request_queue
*, unsigned int);
762 extern void blk_queue_hardsect_size(struct request_queue
*, unsigned short);
763 extern void blk_queue_stack_limits(struct request_queue
*t
, struct request_queue
*b
);
764 extern void blk_queue_segment_boundary(struct request_queue
*, unsigned long);
765 extern void blk_queue_prep_rq(struct request_queue
*, prep_rq_fn
*pfn
);
766 extern void blk_queue_merge_bvec(struct request_queue
*, merge_bvec_fn
*);
767 extern void blk_queue_dma_alignment(struct request_queue
*, int);
768 extern void blk_queue_softirq_done(struct request_queue
*, softirq_done_fn
*);
769 extern struct backing_dev_info
*blk_get_backing_dev_info(struct block_device
*bdev
);
770 extern int blk_queue_ordered(struct request_queue
*, unsigned, prepare_flush_fn
*);
771 extern void blk_queue_issue_flush_fn(struct request_queue
*, issue_flush_fn
*);
772 extern int blk_do_ordered(struct request_queue
*, struct request
**);
773 extern unsigned blk_ordered_cur_seq(struct request_queue
*);
774 extern unsigned blk_ordered_req_seq(struct request
*);
775 extern void blk_ordered_complete_seq(struct request_queue
*, unsigned, int);
777 extern int blk_rq_map_sg(struct request_queue
*, struct request
*, struct scatterlist
*);
778 extern void blk_dump_rq_flags(struct request
*, char *);
779 extern void generic_unplug_device(struct request_queue
*);
780 extern void __generic_unplug_device(struct request_queue
*);
781 extern long nr_blockdev_pages(void);
783 int blk_get_queue(struct request_queue
*);
784 struct request_queue
*blk_alloc_queue(gfp_t
);
785 struct request_queue
*blk_alloc_queue_node(gfp_t
, int);
786 extern void blk_put_queue(struct request_queue
*);
791 #define blk_queue_tag_depth(q) ((q)->queue_tags->busy)
792 #define blk_queue_tag_queue(q) ((q)->queue_tags->busy < (q)->queue_tags->max_depth)
793 #define blk_rq_tagged(rq) ((rq)->cmd_flags & REQ_QUEUED)
794 extern int blk_queue_start_tag(struct request_queue
*, struct request
*);
795 extern struct request
*blk_queue_find_tag(struct request_queue
*, int);
796 extern void blk_queue_end_tag(struct request_queue
*, struct request
*);
797 extern int blk_queue_init_tags(struct request_queue
*, int, struct blk_queue_tag
*);
798 extern void blk_queue_free_tags(struct request_queue
*);
799 extern int blk_queue_resize_tags(struct request_queue
*, int);
800 extern void blk_queue_invalidate_tags(struct request_queue
*);
801 extern struct blk_queue_tag
*blk_init_tags(int);
802 extern void blk_free_tags(struct blk_queue_tag
*);
804 static inline struct request
*blk_map_queue_find_tag(struct blk_queue_tag
*bqt
,
807 if (unlikely(bqt
== NULL
|| tag
>= bqt
->real_max_depth
))
809 return bqt
->tag_index
[tag
];
812 extern void blk_rq_bio_prep(struct request_queue
*, struct request
*, struct bio
*);
813 extern int blkdev_issue_flush(struct block_device
*, sector_t
*);
815 #define MAX_PHYS_SEGMENTS 128
816 #define MAX_HW_SEGMENTS 128
817 #define SAFE_MAX_SECTORS 255
818 #define BLK_DEF_MAX_SECTORS 1024
820 #define MAX_SEGMENT_SIZE 65536
822 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
824 static inline int queue_hardsect_size(struct request_queue
*q
)
828 if (q
&& q
->hardsect_size
)
829 retval
= q
->hardsect_size
;
834 static inline int bdev_hardsect_size(struct block_device
*bdev
)
836 return queue_hardsect_size(bdev_get_queue(bdev
));
839 static inline int queue_dma_alignment(struct request_queue
*q
)
843 if (q
&& q
->dma_alignment
)
844 retval
= q
->dma_alignment
;
849 /* assumes size > 256 */
850 static inline unsigned int blksize_bits(unsigned int size
)
852 unsigned int bits
= 8;
856 } while (size
> 256);
860 static inline unsigned int block_size(struct block_device
*bdev
)
862 return bdev
->bd_block_size
;
865 typedef struct {struct page
*v
;} Sector
;
867 unsigned char *read_dev_sector(struct block_device
*, sector_t
, Sector
*);
869 static inline void put_dev_sector(Sector p
)
871 page_cache_release(p
.v
);
875 int kblockd_schedule_work(struct work_struct
*work
);
876 void kblockd_flush_work(struct work_struct
*work
);
878 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
879 MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
880 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
881 MODULE_ALIAS("block-major-" __stringify(major) "-*")
884 #else /* CONFIG_BLOCK */
886 * stubs for when the block layer is configured out
888 #define buffer_heads_over_limit 0
890 static inline long nr_blockdev_pages(void)
895 static inline void exit_io_context(void)
899 #endif /* CONFIG_BLOCK */