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>
18 #include <asm/scatterlist.h>
21 # include <asm/div64.h>
22 # define sector_div(a, b) do_div(a, b)
24 # define sector_div(n, b)( \
36 struct scsi_ioctl_command
;
39 typedef struct request_queue request_queue_t
;
40 struct elevator_queue
;
41 typedef struct elevator_queue elevator_t
;
42 struct request_pm_state
;
45 #define BLKDEV_MIN_RQ 4
46 #define BLKDEV_MAX_RQ 128 /* Default maximum */
49 * This is the per-process anticipatory I/O scheduler state.
51 struct as_io_context
{
54 void (*dtor
)(struct as_io_context
*aic
); /* destructor */
55 void (*exit
)(struct as_io_context
*aic
); /* called on task exit */
58 atomic_t nr_queued
; /* queued reads & sync writes */
59 atomic_t nr_dispatched
; /* number of requests gone to the drivers */
61 /* IO History tracking */
63 unsigned long last_end_request
;
64 unsigned long ttime_total
;
65 unsigned long ttime_samples
;
66 unsigned long ttime_mean
;
68 unsigned int seek_samples
;
69 sector_t last_request_pos
;
75 struct cfq_io_context
{
76 struct rb_node rb_node
;
79 struct cfq_queue
*cfqq
[2];
81 struct io_context
*ioc
;
83 unsigned long last_end_request
;
84 sector_t last_request_pos
;
86 unsigned long ttime_total
;
87 unsigned long ttime_samples
;
88 unsigned long ttime_mean
;
90 unsigned int seek_samples
;
94 struct list_head queue_list
;
96 void (*dtor
)(struct io_context
*); /* destructor */
97 void (*exit
)(struct io_context
*); /* called on task exit */
101 * This is the per-process I/O subsystem state. It is refcounted and
102 * kmalloc'ed. Currently all fields are modified in process io context
103 * (apart from the atomic refcount), so require no locking.
107 struct task_struct
*task
;
109 unsigned int ioprio_changed
;
112 * For request batching
114 unsigned long last_waited
; /* Time last woken after wait for request */
115 int nr_batch_requests
; /* Number of requests left in the batch */
117 struct as_io_context
*aic
;
118 struct rb_root cic_root
;
121 void put_io_context(struct io_context
*ioc
);
122 void exit_io_context(void);
123 struct io_context
*get_io_context(gfp_t gfp_flags
, int node
);
124 void copy_io_context(struct io_context
**pdst
, struct io_context
**psrc
);
125 void swap_io_context(struct io_context
**ioc1
, struct io_context
**ioc2
);
128 typedef void (rq_end_io_fn
)(struct request
*, int);
130 struct request_list
{
135 wait_queue_head_t wait
[2];
139 * request command types
141 enum rq_cmd_type_bits
{
142 REQ_TYPE_FS
= 1, /* fs request */
143 REQ_TYPE_BLOCK_PC
, /* scsi command */
144 REQ_TYPE_SENSE
, /* sense request */
145 REQ_TYPE_PM_SUSPEND
, /* suspend request */
146 REQ_TYPE_PM_RESUME
, /* resume request */
147 REQ_TYPE_PM_SHUTDOWN
, /* shutdown request */
148 REQ_TYPE_FLUSH
, /* flush request */
149 REQ_TYPE_SPECIAL
, /* driver defined type */
150 REQ_TYPE_LINUX_BLOCK
, /* generic block layer message */
152 * for ATA/ATAPI devices. this really doesn't belong here, ide should
153 * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver
154 * private REQ_LB opcodes to differentiate what type of request this is
158 REQ_TYPE_ATA_TASKFILE
,
163 * For request of type REQ_TYPE_LINUX_BLOCK, rq->cmd[0] is the opcode being
164 * sent down (similar to how REQ_TYPE_BLOCK_PC means that ->cmd[] holds a
167 * 0x00 -> 0x3f are driver private, to be used for whatever purpose they need,
168 * typically to differentiate REQ_TYPE_SPECIAL requests.
173 * just examples for now
175 REQ_LB_OP_EJECT
= 0x40, /* eject request */
176 REQ_LB_OP_FLUSH
= 0x41, /* flush device */
180 * request type modified bits. first three bits match BIO_RW* bits, important
183 __REQ_RW
, /* not set, read. set, write */
184 __REQ_FAILFAST
, /* no low level driver retries */
185 __REQ_SORTED
, /* elevator knows about this request */
186 __REQ_SOFTBARRIER
, /* may not be passed by ioscheduler */
187 __REQ_HARDBARRIER
, /* may not be passed by drive either */
188 __REQ_FUA
, /* forced unit access */
189 __REQ_NOMERGE
, /* don't touch this for merging */
190 __REQ_STARTED
, /* drive already may have started this one */
191 __REQ_DONTPREP
, /* don't call prep for this one */
192 __REQ_QUEUED
, /* uses queueing */
193 __REQ_ELVPRIV
, /* elevator private data attached */
194 __REQ_FAILED
, /* set if the request failed */
195 __REQ_QUIET
, /* don't worry about errors */
196 __REQ_PREEMPT
, /* set for "ide_preempt" requests */
197 __REQ_ORDERED_COLOR
, /* is before or after barrier */
198 __REQ_RW_SYNC
, /* request is sync (O_DIRECT) */
199 __REQ_ALLOCED
, /* request came from our alloc pool */
200 __REQ_RW_META
, /* metadata io request */
201 __REQ_NR_BITS
, /* stops here */
204 #define REQ_RW (1 << __REQ_RW)
205 #define REQ_FAILFAST (1 << __REQ_FAILFAST)
206 #define REQ_SORTED (1 << __REQ_SORTED)
207 #define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER)
208 #define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER)
209 #define REQ_FUA (1 << __REQ_FUA)
210 #define REQ_NOMERGE (1 << __REQ_NOMERGE)
211 #define REQ_STARTED (1 << __REQ_STARTED)
212 #define REQ_DONTPREP (1 << __REQ_DONTPREP)
213 #define REQ_QUEUED (1 << __REQ_QUEUED)
214 #define REQ_ELVPRIV (1 << __REQ_ELVPRIV)
215 #define REQ_FAILED (1 << __REQ_FAILED)
216 #define REQ_QUIET (1 << __REQ_QUIET)
217 #define REQ_PREEMPT (1 << __REQ_PREEMPT)
218 #define REQ_ORDERED_COLOR (1 << __REQ_ORDERED_COLOR)
219 #define REQ_RW_SYNC (1 << __REQ_RW_SYNC)
220 #define REQ_ALLOCED (1 << __REQ_ALLOCED)
221 #define REQ_RW_META (1 << __REQ_RW_META)
223 #define BLK_MAX_CDB 16
226 * try to put the fields that are referenced together in the same cacheline
229 struct list_head queuelist
;
230 struct list_head donelist
;
234 unsigned int cmd_flags
;
235 enum rq_cmd_type_bits cmd_type
;
237 /* Maintain bio traversal state for part by part I/O submission.
238 * hard_* are block layer internals, no driver should touch them!
241 sector_t sector
; /* next sector to submit */
242 sector_t hard_sector
; /* next sector to complete */
243 unsigned long nr_sectors
; /* no. of sectors left to submit */
244 unsigned long hard_nr_sectors
; /* no. of sectors left to complete */
245 /* no. of sectors left to submit in the current segment */
246 unsigned int current_nr_sectors
;
248 /* no. of sectors left to complete in the current segment */
249 unsigned int hard_cur_sectors
;
254 struct hlist_node hash
; /* merge hash */
256 * The rb_node is only used inside the io scheduler, requests
257 * are pruned when moved to the dispatch queue. So let the
258 * completion_data share space with the rb_node.
261 struct rb_node rb_node
; /* sort/lookup */
262 void *completion_data
;
266 * two pointers are available for the IO schedulers, if they need
267 * more they have to dynamically allocate it.
269 void *elevator_private
;
270 void *elevator_private2
;
272 struct gendisk
*rq_disk
;
273 unsigned long start_time
;
275 /* Number of scatter-gather DMA addr+len pairs after
276 * physical address coalescing is performed.
278 unsigned short nr_phys_segments
;
280 /* Number of scatter-gather addr+len pairs after
281 * physical and DMA remapping hardware coalescing is performed.
282 * This is the number of scatter-gather entries the driver
283 * will actually have to deal with after DMA mapping is done.
285 unsigned short nr_hw_segments
;
287 unsigned short ioprio
;
298 * when request is used as a packet command carrier
300 unsigned int cmd_len
;
301 unsigned char cmd
[BLK_MAX_CDB
];
303 unsigned int data_len
;
304 unsigned int sense_len
;
308 unsigned int timeout
;
312 * completion callback.
314 rq_end_io_fn
*end_io
;
319 * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
320 * requests. Some step values could eventually be made generic.
322 struct request_pm_state
324 /* PM state machine step value, currently driver specific */
326 /* requested PM state value (S1, S2, S3, S4, ...) */
328 void* data
; /* for driver use */
331 #include <linux/elevator.h>
333 typedef void (request_fn_proc
) (request_queue_t
*q
);
334 typedef int (make_request_fn
) (request_queue_t
*q
, struct bio
*bio
);
335 typedef int (prep_rq_fn
) (request_queue_t
*, struct request
*);
336 typedef void (unplug_fn
) (request_queue_t
*);
339 typedef int (merge_bvec_fn
) (request_queue_t
*, struct bio
*, struct bio_vec
*);
340 typedef int (issue_flush_fn
) (request_queue_t
*, struct gendisk
*, sector_t
*);
341 typedef void (prepare_flush_fn
) (request_queue_t
*, struct request
*);
342 typedef void (softirq_done_fn
)(struct request
*);
344 enum blk_queue_state
{
349 struct blk_queue_tag
{
350 struct request
**tag_index
; /* map of busy tags */
351 unsigned long *tag_map
; /* bit map of free/busy tags */
352 struct list_head busy_list
; /* fifo list of busy tags */
353 int busy
; /* current depth */
354 int max_depth
; /* what we will send to device */
355 int real_max_depth
; /* what the array can hold */
356 atomic_t refcnt
; /* map can be shared */
362 * Together with queue_head for cacheline sharing
364 struct list_head queue_head
;
365 struct request
*last_merge
;
366 elevator_t
*elevator
;
369 * the queue request freelist, one for reads and one for writes
371 struct request_list rq
;
373 request_fn_proc
*request_fn
;
374 make_request_fn
*make_request_fn
;
375 prep_rq_fn
*prep_rq_fn
;
376 unplug_fn
*unplug_fn
;
377 merge_bvec_fn
*merge_bvec_fn
;
378 issue_flush_fn
*issue_flush_fn
;
379 prepare_flush_fn
*prepare_flush_fn
;
380 softirq_done_fn
*softirq_done_fn
;
383 * Dispatch queue sorting
386 struct request
*boundary_rq
;
389 * Auto-unplugging state
391 struct timer_list unplug_timer
;
392 int unplug_thresh
; /* After this many requests */
393 unsigned long unplug_delay
; /* After this many jiffies */
394 struct work_struct unplug_work
;
396 struct backing_dev_info backing_dev_info
;
399 * The queue owner gets to use this for whatever they like.
400 * ll_rw_blk doesn't touch it.
405 * queue needs bounce pages for pages above this limit
407 unsigned long bounce_pfn
;
411 * various queue flags, see QUEUE_* below
413 unsigned long queue_flags
;
416 * protects queue structures from reentrancy. ->__queue_lock should
417 * _never_ be used directly, it is queue private. always use
420 spinlock_t __queue_lock
;
421 spinlock_t
*queue_lock
;
431 unsigned long nr_requests
; /* Max # of requests */
432 unsigned int nr_congestion_on
;
433 unsigned int nr_congestion_off
;
434 unsigned int nr_batching
;
436 unsigned int max_sectors
;
437 unsigned int max_hw_sectors
;
438 unsigned short max_phys_segments
;
439 unsigned short max_hw_segments
;
440 unsigned short hardsect_size
;
441 unsigned int max_segment_size
;
443 unsigned long seg_boundary_mask
;
444 unsigned int dma_alignment
;
446 struct blk_queue_tag
*queue_tags
;
448 unsigned int nr_sorted
;
449 unsigned int in_flight
;
454 unsigned int sg_timeout
;
455 unsigned int sg_reserved_size
;
457 #ifdef CONFIG_BLK_DEV_IO_TRACE
458 struct blk_trace
*blk_trace
;
461 * reserved for flush operations
463 unsigned int ordered
, next_ordered
, ordseq
;
464 int orderr
, ordcolor
;
465 struct request pre_flush_rq
, bar_rq
, post_flush_rq
;
466 struct request
*orig_bar_rq
;
467 unsigned int bi_size
;
469 struct mutex sysfs_lock
;
472 #define QUEUE_FLAG_CLUSTER 0 /* cluster several segments into 1 */
473 #define QUEUE_FLAG_QUEUED 1 /* uses generic tag queueing */
474 #define QUEUE_FLAG_STOPPED 2 /* queue is stopped */
475 #define QUEUE_FLAG_READFULL 3 /* write queue has been filled */
476 #define QUEUE_FLAG_WRITEFULL 4 /* read queue has been filled */
477 #define QUEUE_FLAG_DEAD 5 /* queue being torn down */
478 #define QUEUE_FLAG_REENTER 6 /* Re-entrancy avoidance */
479 #define QUEUE_FLAG_PLUGGED 7 /* queue is plugged */
480 #define QUEUE_FLAG_ELVSWITCH 8 /* don't use elevator, just do FIFO */
484 * Hardbarrier is supported with one of the following methods.
486 * NONE : hardbarrier unsupported
487 * DRAIN : ordering by draining is enough
488 * DRAIN_FLUSH : ordering by draining w/ pre and post flushes
489 * DRAIN_FUA : ordering by draining w/ pre flush and FUA write
490 * TAG : ordering by tag is enough
491 * TAG_FLUSH : ordering by tag w/ pre and post flushes
492 * TAG_FUA : ordering by tag w/ pre flush and FUA write
494 QUEUE_ORDERED_NONE
= 0x00,
495 QUEUE_ORDERED_DRAIN
= 0x01,
496 QUEUE_ORDERED_TAG
= 0x02,
498 QUEUE_ORDERED_PREFLUSH
= 0x10,
499 QUEUE_ORDERED_POSTFLUSH
= 0x20,
500 QUEUE_ORDERED_FUA
= 0x40,
502 QUEUE_ORDERED_DRAIN_FLUSH
= QUEUE_ORDERED_DRAIN
|
503 QUEUE_ORDERED_PREFLUSH
| QUEUE_ORDERED_POSTFLUSH
,
504 QUEUE_ORDERED_DRAIN_FUA
= QUEUE_ORDERED_DRAIN
|
505 QUEUE_ORDERED_PREFLUSH
| QUEUE_ORDERED_FUA
,
506 QUEUE_ORDERED_TAG_FLUSH
= QUEUE_ORDERED_TAG
|
507 QUEUE_ORDERED_PREFLUSH
| QUEUE_ORDERED_POSTFLUSH
,
508 QUEUE_ORDERED_TAG_FUA
= QUEUE_ORDERED_TAG
|
509 QUEUE_ORDERED_PREFLUSH
| QUEUE_ORDERED_FUA
,
512 * Ordered operation sequence
514 QUEUE_ORDSEQ_STARTED
= 0x01, /* flushing in progress */
515 QUEUE_ORDSEQ_DRAIN
= 0x02, /* waiting for the queue to be drained */
516 QUEUE_ORDSEQ_PREFLUSH
= 0x04, /* pre-flushing in progress */
517 QUEUE_ORDSEQ_BAR
= 0x08, /* original barrier req in progress */
518 QUEUE_ORDSEQ_POSTFLUSH
= 0x10, /* post-flushing in progress */
519 QUEUE_ORDSEQ_DONE
= 0x20,
522 #define blk_queue_plugged(q) test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
523 #define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
524 #define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
525 #define blk_queue_flushing(q) ((q)->ordseq)
527 #define blk_fs_request(rq) ((rq)->cmd_type == REQ_TYPE_FS)
528 #define blk_pc_request(rq) ((rq)->cmd_type == REQ_TYPE_BLOCK_PC)
529 #define blk_special_request(rq) ((rq)->cmd_type == REQ_TYPE_SPECIAL)
530 #define blk_sense_request(rq) ((rq)->cmd_type == REQ_TYPE_SENSE)
532 #define blk_noretry_request(rq) ((rq)->cmd_flags & REQ_FAILFAST)
533 #define blk_rq_started(rq) ((rq)->cmd_flags & REQ_STARTED)
535 #define blk_account_rq(rq) (blk_rq_started(rq) && blk_fs_request(rq))
537 #define blk_pm_suspend_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND)
538 #define blk_pm_resume_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_RESUME)
539 #define blk_pm_request(rq) \
540 (blk_pm_suspend_request(rq) || blk_pm_resume_request(rq))
542 #define blk_sorted_rq(rq) ((rq)->cmd_flags & REQ_SORTED)
543 #define blk_barrier_rq(rq) ((rq)->cmd_flags & REQ_HARDBARRIER)
544 #define blk_fua_rq(rq) ((rq)->cmd_flags & REQ_FUA)
546 #define list_entry_rq(ptr) list_entry((ptr), struct request, queuelist)
548 #define rq_data_dir(rq) ((rq)->cmd_flags & 1)
551 * We regard a request as sync, if it's a READ or a SYNC write.
553 #define rq_is_sync(rq) (rq_data_dir((rq)) == READ || (rq)->cmd_flags & REQ_RW_SYNC)
554 #define rq_is_meta(rq) ((rq)->cmd_flags & REQ_RW_META)
556 static inline int blk_queue_full(struct request_queue
*q
, int rw
)
559 return test_bit(QUEUE_FLAG_READFULL
, &q
->queue_flags
);
560 return test_bit(QUEUE_FLAG_WRITEFULL
, &q
->queue_flags
);
563 static inline void blk_set_queue_full(struct request_queue
*q
, int rw
)
566 set_bit(QUEUE_FLAG_READFULL
, &q
->queue_flags
);
568 set_bit(QUEUE_FLAG_WRITEFULL
, &q
->queue_flags
);
571 static inline void blk_clear_queue_full(struct request_queue
*q
, int rw
)
574 clear_bit(QUEUE_FLAG_READFULL
, &q
->queue_flags
);
576 clear_bit(QUEUE_FLAG_WRITEFULL
, &q
->queue_flags
);
581 * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
582 * it already be started by driver.
584 #define RQ_NOMERGE_FLAGS \
585 (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER)
586 #define rq_mergeable(rq) \
587 (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && blk_fs_request((rq)))
590 * q->prep_rq_fn return values
592 #define BLKPREP_OK 0 /* serve it */
593 #define BLKPREP_KILL 1 /* fatal error, kill */
594 #define BLKPREP_DEFER 2 /* leave on queue */
596 extern unsigned long blk_max_low_pfn
, blk_max_pfn
;
599 * standard bounce addresses:
601 * BLK_BOUNCE_HIGH : bounce all highmem pages
602 * BLK_BOUNCE_ANY : don't bounce anything
603 * BLK_BOUNCE_ISA : bounce pages above ISA DMA boundary
605 #define BLK_BOUNCE_HIGH ((u64)blk_max_low_pfn << PAGE_SHIFT)
606 #define BLK_BOUNCE_ANY ((u64)blk_max_pfn << PAGE_SHIFT)
607 #define BLK_BOUNCE_ISA (ISA_DMA_THRESHOLD)
610 extern int init_emergency_isa_pool(void);
611 extern void blk_queue_bounce(request_queue_t
*q
, struct bio
**bio
);
613 static inline int init_emergency_isa_pool(void)
617 static inline void blk_queue_bounce(request_queue_t
*q
, struct bio
**bio
)
620 #endif /* CONFIG_MMU */
622 #define rq_for_each_bio(_bio, rq) \
624 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
626 extern int blk_register_queue(struct gendisk
*disk
);
627 extern void blk_unregister_queue(struct gendisk
*disk
);
628 extern void register_disk(struct gendisk
*dev
);
629 extern void generic_make_request(struct bio
*bio
);
630 extern void blk_put_request(struct request
*);
631 extern void __blk_put_request(request_queue_t
*, struct request
*);
632 extern void blk_end_sync_rq(struct request
*rq
, int error
);
633 extern struct request
*blk_get_request(request_queue_t
*, int, gfp_t
);
634 extern void blk_insert_request(request_queue_t
*, struct request
*, int, void *);
635 extern void blk_requeue_request(request_queue_t
*, struct request
*);
636 extern void blk_plug_device(request_queue_t
*);
637 extern int blk_remove_plug(request_queue_t
*);
638 extern void blk_recount_segments(request_queue_t
*, struct bio
*);
639 extern int scsi_cmd_ioctl(struct file
*, struct gendisk
*, unsigned int, void __user
*);
640 extern int sg_scsi_ioctl(struct file
*, struct request_queue
*,
641 struct gendisk
*, struct scsi_ioctl_command __user
*);
644 * Temporary export, until SCSI gets fixed up.
646 extern int ll_back_merge_fn(request_queue_t
*, struct request
*, struct bio
*);
649 * A queue has just exitted congestion. Note this in the global counter of
650 * congested queues, and wake up anyone who was waiting for requests to be
653 static inline void blk_clear_queue_congested(request_queue_t
*q
, int rw
)
655 clear_bdi_congested(&q
->backing_dev_info
, rw
);
659 * A queue has just entered congestion. Flag that in the queue's VM-visible
660 * state flags and increment the global gounter of congested queues.
662 static inline void blk_set_queue_congested(request_queue_t
*q
, int rw
)
664 set_bdi_congested(&q
->backing_dev_info
, rw
);
667 extern void blk_start_queue(request_queue_t
*q
);
668 extern void blk_stop_queue(request_queue_t
*q
);
669 extern void blk_sync_queue(struct request_queue
*q
);
670 extern void __blk_stop_queue(request_queue_t
*q
);
671 extern void blk_run_queue(request_queue_t
*);
672 extern void blk_start_queueing(request_queue_t
*);
673 extern int blk_rq_map_user(request_queue_t
*, struct request
*, void __user
*, unsigned long);
674 extern int blk_rq_unmap_user(struct bio
*);
675 extern int blk_rq_map_kern(request_queue_t
*, struct request
*, void *, unsigned int, gfp_t
);
676 extern int blk_rq_map_user_iov(request_queue_t
*, struct request
*,
677 struct sg_iovec
*, int, unsigned int);
678 extern int blk_execute_rq(request_queue_t
*, struct gendisk
*,
679 struct request
*, int);
680 extern void blk_execute_rq_nowait(request_queue_t
*, struct gendisk
*,
681 struct request
*, int, rq_end_io_fn
*);
683 static inline request_queue_t
*bdev_get_queue(struct block_device
*bdev
)
685 return bdev
->bd_disk
->queue
;
688 static inline void blk_run_backing_dev(struct backing_dev_info
*bdi
,
691 if (bdi
&& bdi
->unplug_io_fn
)
692 bdi
->unplug_io_fn(bdi
, page
);
695 static inline void blk_run_address_space(struct address_space
*mapping
)
698 blk_run_backing_dev(mapping
->backing_dev_info
, NULL
);
702 * end_request() and friends. Must be called with the request queue spinlock
703 * acquired. All functions called within end_request() _must_be_ atomic.
705 * Several drivers define their own end_request and call
706 * end_that_request_first() and end_that_request_last()
707 * for parts of the original function. This prevents
708 * code duplication in drivers.
710 extern int end_that_request_first(struct request
*, int, int);
711 extern int end_that_request_chunk(struct request
*, int, int);
712 extern void end_that_request_last(struct request
*, int);
713 extern void end_request(struct request
*req
, int uptodate
);
714 extern void blk_complete_request(struct request
*);
717 * end_that_request_first/chunk() takes an uptodate argument. we account
718 * any value <= as an io error. 0 means -EIO for compatability reasons,
719 * any other < 0 value is the direct error type. An uptodate value of
720 * 1 indicates successful io completion
722 #define end_io_error(uptodate) (unlikely((uptodate) <= 0))
724 static inline void blkdev_dequeue_request(struct request
*req
)
726 elv_dequeue_request(req
->q
, req
);
730 * Access functions for manipulating queue properties
732 extern request_queue_t
*blk_init_queue_node(request_fn_proc
*rfn
,
733 spinlock_t
*lock
, int node_id
);
734 extern request_queue_t
*blk_init_queue(request_fn_proc
*, spinlock_t
*);
735 extern void blk_cleanup_queue(request_queue_t
*);
736 extern void blk_queue_make_request(request_queue_t
*, make_request_fn
*);
737 extern void blk_queue_bounce_limit(request_queue_t
*, u64
);
738 extern void blk_queue_max_sectors(request_queue_t
*, unsigned int);
739 extern void blk_queue_max_phys_segments(request_queue_t
*, unsigned short);
740 extern void blk_queue_max_hw_segments(request_queue_t
*, unsigned short);
741 extern void blk_queue_max_segment_size(request_queue_t
*, unsigned int);
742 extern void blk_queue_hardsect_size(request_queue_t
*, unsigned short);
743 extern void blk_queue_stack_limits(request_queue_t
*t
, request_queue_t
*b
);
744 extern void blk_queue_segment_boundary(request_queue_t
*, unsigned long);
745 extern void blk_queue_prep_rq(request_queue_t
*, prep_rq_fn
*pfn
);
746 extern void blk_queue_merge_bvec(request_queue_t
*, merge_bvec_fn
*);
747 extern void blk_queue_dma_alignment(request_queue_t
*, int);
748 extern void blk_queue_softirq_done(request_queue_t
*, softirq_done_fn
*);
749 extern struct backing_dev_info
*blk_get_backing_dev_info(struct block_device
*bdev
);
750 extern int blk_queue_ordered(request_queue_t
*, unsigned, prepare_flush_fn
*);
751 extern void blk_queue_issue_flush_fn(request_queue_t
*, issue_flush_fn
*);
752 extern int blk_do_ordered(request_queue_t
*, struct request
**);
753 extern unsigned blk_ordered_cur_seq(request_queue_t
*);
754 extern unsigned blk_ordered_req_seq(struct request
*);
755 extern void blk_ordered_complete_seq(request_queue_t
*, unsigned, int);
757 extern int blk_rq_map_sg(request_queue_t
*, struct request
*, struct scatterlist
*);
758 extern void blk_dump_rq_flags(struct request
*, char *);
759 extern void generic_unplug_device(request_queue_t
*);
760 extern void __generic_unplug_device(request_queue_t
*);
761 extern long nr_blockdev_pages(void);
763 int blk_get_queue(request_queue_t
*);
764 request_queue_t
*blk_alloc_queue(gfp_t
);
765 request_queue_t
*blk_alloc_queue_node(gfp_t
, int);
766 extern void blk_put_queue(request_queue_t
*);
771 #define blk_queue_tag_depth(q) ((q)->queue_tags->busy)
772 #define blk_queue_tag_queue(q) ((q)->queue_tags->busy < (q)->queue_tags->max_depth)
773 #define blk_rq_tagged(rq) ((rq)->cmd_flags & REQ_QUEUED)
774 extern int blk_queue_start_tag(request_queue_t
*, struct request
*);
775 extern struct request
*blk_queue_find_tag(request_queue_t
*, int);
776 extern void blk_queue_end_tag(request_queue_t
*, struct request
*);
777 extern int blk_queue_init_tags(request_queue_t
*, int, struct blk_queue_tag
*);
778 extern void blk_queue_free_tags(request_queue_t
*);
779 extern int blk_queue_resize_tags(request_queue_t
*, int);
780 extern void blk_queue_invalidate_tags(request_queue_t
*);
781 extern struct blk_queue_tag
*blk_init_tags(int);
782 extern void blk_free_tags(struct blk_queue_tag
*);
784 static inline struct request
*blk_map_queue_find_tag(struct blk_queue_tag
*bqt
,
787 if (unlikely(bqt
== NULL
|| tag
>= bqt
->real_max_depth
))
789 return bqt
->tag_index
[tag
];
792 extern void blk_rq_bio_prep(request_queue_t
*, struct request
*, struct bio
*);
793 extern int blkdev_issue_flush(struct block_device
*, sector_t
*);
795 #define MAX_PHYS_SEGMENTS 128
796 #define MAX_HW_SEGMENTS 128
797 #define SAFE_MAX_SECTORS 255
798 #define BLK_DEF_MAX_SECTORS 1024
800 #define MAX_SEGMENT_SIZE 65536
802 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
804 static inline int queue_hardsect_size(request_queue_t
*q
)
808 if (q
&& q
->hardsect_size
)
809 retval
= q
->hardsect_size
;
814 static inline int bdev_hardsect_size(struct block_device
*bdev
)
816 return queue_hardsect_size(bdev_get_queue(bdev
));
819 static inline int queue_dma_alignment(request_queue_t
*q
)
823 if (q
&& q
->dma_alignment
)
824 retval
= q
->dma_alignment
;
829 /* assumes size > 256 */
830 static inline unsigned int blksize_bits(unsigned int size
)
832 unsigned int bits
= 8;
836 } while (size
> 256);
840 static inline unsigned int block_size(struct block_device
*bdev
)
842 return bdev
->bd_block_size
;
845 typedef struct {struct page
*v
;} Sector
;
847 unsigned char *read_dev_sector(struct block_device
*, sector_t
, Sector
*);
849 static inline void put_dev_sector(Sector p
)
851 page_cache_release(p
.v
);
855 int kblockd_schedule_work(struct work_struct
*work
);
856 void kblockd_flush(void);
858 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
859 MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
860 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
861 MODULE_ALIAS("block-major-" __stringify(major) "-*")
864 #else /* CONFIG_BLOCK */
866 * stubs for when the block layer is configured out
868 #define buffer_heads_over_limit 0
870 static inline long blk_congestion_wait(int rw
, long timeout
)
872 return io_schedule_timeout(timeout
);
875 static inline long nr_blockdev_pages(void)
880 static inline void exit_io_context(void)
884 #endif /* CONFIG_BLOCK */