1 #ifndef _LINUX_BLKDEV_H
2 #define _LINUX_BLKDEV_H
4 #include <linux/major.h>
5 #include <linux/genhd.h>
6 #include <linux/list.h>
7 #include <linux/timer.h>
8 #include <linux/workqueue.h>
9 #include <linux/pagemap.h>
10 #include <linux/backing-dev.h>
11 #include <linux/wait.h>
12 #include <linux/mempool.h>
13 #include <linux/bio.h>
14 #include <linux/module.h>
15 #include <linux/stringify.h>
17 #include <asm/scatterlist.h>
19 struct scsi_ioctl_command
;
22 typedef struct request_queue request_queue_t
;
23 struct elevator_queue
;
24 typedef struct elevator_queue elevator_t
;
25 struct request_pm_state
;
28 #define BLKDEV_MIN_RQ 4
29 #define BLKDEV_MAX_RQ 128 /* Default maximum */
32 * This is the per-process anticipatory I/O scheduler state.
34 struct as_io_context
{
37 void (*dtor
)(struct as_io_context
*aic
); /* destructor */
38 void (*exit
)(struct as_io_context
*aic
); /* called on task exit */
41 atomic_t nr_queued
; /* queued reads & sync writes */
42 atomic_t nr_dispatched
; /* number of requests gone to the drivers */
44 /* IO History tracking */
46 unsigned long last_end_request
;
47 unsigned long ttime_total
;
48 unsigned long ttime_samples
;
49 unsigned long ttime_mean
;
51 unsigned int seek_samples
;
52 sector_t last_request_pos
;
58 struct cfq_io_context
{
59 struct rb_node rb_node
;
62 struct cfq_queue
*cfqq
[2];
64 struct io_context
*ioc
;
66 unsigned long last_end_request
;
67 sector_t last_request_pos
;
68 unsigned long last_queue
;
70 unsigned long ttime_total
;
71 unsigned long ttime_samples
;
72 unsigned long ttime_mean
;
74 unsigned int seek_samples
;
78 struct list_head queue_list
;
80 void (*dtor
)(struct io_context
*); /* destructor */
81 void (*exit
)(struct io_context
*); /* called on task exit */
85 * This is the per-process I/O subsystem state. It is refcounted and
86 * kmalloc'ed. Currently all fields are modified in process io context
87 * (apart from the atomic refcount), so require no locking.
91 struct task_struct
*task
;
93 int (*set_ioprio
)(struct io_context
*, unsigned int);
96 * For request batching
98 unsigned long last_waited
; /* Time last woken after wait for request */
99 int nr_batch_requests
; /* Number of requests left in the batch */
101 struct as_io_context
*aic
;
102 struct rb_root cic_root
;
105 void put_io_context(struct io_context
*ioc
);
106 void exit_io_context(void);
107 struct io_context
*current_io_context(gfp_t gfp_flags
);
108 struct io_context
*get_io_context(gfp_t gfp_flags
);
109 void copy_io_context(struct io_context
**pdst
, struct io_context
**psrc
);
110 void swap_io_context(struct io_context
**ioc1
, struct io_context
**ioc2
);
113 typedef void (rq_end_io_fn
)(struct request
*, int);
115 struct request_list
{
120 wait_queue_head_t wait
[2];
124 * request command types
126 enum rq_cmd_type_bits
{
127 REQ_TYPE_FS
= 1, /* fs request */
128 REQ_TYPE_BLOCK_PC
, /* scsi command */
129 REQ_TYPE_SENSE
, /* sense request */
130 REQ_TYPE_PM_SUSPEND
, /* suspend request */
131 REQ_TYPE_PM_RESUME
, /* resume request */
132 REQ_TYPE_PM_SHUTDOWN
, /* shutdown request */
133 REQ_TYPE_FLUSH
, /* flush request */
134 REQ_TYPE_SPECIAL
, /* driver defined type */
135 REQ_TYPE_LINUX_BLOCK
, /* generic block layer message */
137 * for ATA/ATAPI devices. this really doesn't belong here, ide should
138 * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver
139 * private REQ_LB opcodes to differentiate what type of request this is
143 REQ_TYPE_ATA_TASKFILE
,
147 * For request of type REQ_TYPE_LINUX_BLOCK, rq->cmd[0] is the opcode being
148 * sent down (similar to how REQ_TYPE_BLOCK_PC means that ->cmd[] holds a
151 * 0x00 -> 0x3f are driver private, to be used for whatever purpose they need,
152 * typically to differentiate REQ_TYPE_SPECIAL requests.
157 * just examples for now
159 REQ_LB_OP_EJECT
= 0x40, /* eject request */
160 REQ_LB_OP_FLUSH
= 0x41, /* flush device */
164 * request type modified bits. first three bits match BIO_RW* bits, important
167 __REQ_RW
, /* not set, read. set, write */
168 __REQ_FAILFAST
, /* no low level driver retries */
169 __REQ_SORTED
, /* elevator knows about this request */
170 __REQ_SOFTBARRIER
, /* may not be passed by ioscheduler */
171 __REQ_HARDBARRIER
, /* may not be passed by drive either */
172 __REQ_FUA
, /* forced unit access */
173 __REQ_NOMERGE
, /* don't touch this for merging */
174 __REQ_STARTED
, /* drive already may have started this one */
175 __REQ_DONTPREP
, /* don't call prep for this one */
176 __REQ_QUEUED
, /* uses queueing */
177 __REQ_ELVPRIV
, /* elevator private data attached */
178 __REQ_FAILED
, /* set if the request failed */
179 __REQ_QUIET
, /* don't worry about errors */
180 __REQ_PREEMPT
, /* set for "ide_preempt" requests */
181 __REQ_ORDERED_COLOR
, /* is before or after barrier */
182 __REQ_RW_SYNC
, /* request is sync (O_DIRECT) */
183 __REQ_NR_BITS
, /* stops here */
186 #define REQ_RW (1 << __REQ_RW)
187 #define REQ_FAILFAST (1 << __REQ_FAILFAST)
188 #define REQ_SORTED (1 << __REQ_SORTED)
189 #define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER)
190 #define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER)
191 #define REQ_FUA (1 << __REQ_FUA)
192 #define REQ_NOMERGE (1 << __REQ_NOMERGE)
193 #define REQ_STARTED (1 << __REQ_STARTED)
194 #define REQ_DONTPREP (1 << __REQ_DONTPREP)
195 #define REQ_QUEUED (1 << __REQ_QUEUED)
196 #define REQ_ELVPRIV (1 << __REQ_ELVPRIV)
197 #define REQ_FAILED (1 << __REQ_FAILED)
198 #define REQ_QUIET (1 << __REQ_QUIET)
199 #define REQ_PREEMPT (1 << __REQ_PREEMPT)
200 #define REQ_ORDERED_COLOR (1 << __REQ_ORDERED_COLOR)
201 #define REQ_RW_SYNC (1 << __REQ_RW_SYNC)
203 #define BLK_MAX_CDB 16
206 * try to put the fields that are referenced together in the same cacheline
209 struct list_head queuelist
;
210 struct list_head donelist
;
212 unsigned int cmd_flags
;
213 enum rq_cmd_type_bits cmd_type
;
215 /* Maintain bio traversal state for part by part I/O submission.
216 * hard_* are block layer internals, no driver should touch them!
219 sector_t sector
; /* next sector to submit */
220 unsigned long nr_sectors
; /* no. of sectors left to submit */
221 /* no. of sectors left to submit in the current segment */
222 unsigned int current_nr_sectors
;
224 sector_t hard_sector
; /* next sector to complete */
225 unsigned long hard_nr_sectors
; /* no. of sectors left to complete */
226 /* no. of sectors left to complete in the current segment */
227 unsigned int hard_cur_sectors
;
232 void *elevator_private
;
233 void *completion_data
;
235 int rq_status
; /* should split this into a few status bits */
237 struct gendisk
*rq_disk
;
238 unsigned long start_time
;
240 /* Number of scatter-gather DMA addr+len pairs after
241 * physical address coalescing is performed.
243 unsigned short nr_phys_segments
;
245 /* Number of scatter-gather addr+len pairs after
246 * physical and DMA remapping hardware coalescing is performed.
247 * This is the number of scatter-gather entries the driver
248 * will actually have to deal with after DMA mapping is done.
250 unsigned short nr_hw_segments
;
252 unsigned short ioprio
;
258 struct request_list
*rl
;
260 struct completion
*waiting
;
265 * when request is used as a packet command carrier
267 unsigned int cmd_len
;
268 unsigned char cmd
[BLK_MAX_CDB
];
270 unsigned int data_len
;
271 unsigned int sense_len
;
275 unsigned int timeout
;
279 * completion callback. end_io_data should be folded in with waiting
281 rq_end_io_fn
*end_io
;
286 * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
287 * requests. Some step values could eventually be made generic.
289 struct request_pm_state
291 /* PM state machine step value, currently driver specific */
293 /* requested PM state value (S1, S2, S3, S4, ...) */
295 void* data
; /* for driver use */
298 #include <linux/elevator.h>
300 typedef int (merge_request_fn
) (request_queue_t
*, struct request
*,
302 typedef int (merge_requests_fn
) (request_queue_t
*, struct request
*,
304 typedef void (request_fn_proc
) (request_queue_t
*q
);
305 typedef int (make_request_fn
) (request_queue_t
*q
, struct bio
*bio
);
306 typedef int (prep_rq_fn
) (request_queue_t
*, struct request
*);
307 typedef void (unplug_fn
) (request_queue_t
*);
310 typedef int (merge_bvec_fn
) (request_queue_t
*, struct bio
*, struct bio_vec
*);
311 typedef void (activity_fn
) (void *data
, int rw
);
312 typedef int (issue_flush_fn
) (request_queue_t
*, struct gendisk
*, sector_t
*);
313 typedef void (prepare_flush_fn
) (request_queue_t
*, struct request
*);
314 typedef void (softirq_done_fn
)(struct request
*);
316 enum blk_queue_state
{
321 struct blk_queue_tag
{
322 struct request
**tag_index
; /* map of busy tags */
323 unsigned long *tag_map
; /* bit map of free/busy tags */
324 struct list_head busy_list
; /* fifo list of busy tags */
325 int busy
; /* current depth */
326 int max_depth
; /* what we will send to device */
327 int real_max_depth
; /* what the array can hold */
328 atomic_t refcnt
; /* map can be shared */
334 * Together with queue_head for cacheline sharing
336 struct list_head queue_head
;
337 struct request
*last_merge
;
338 elevator_t
*elevator
;
341 * the queue request freelist, one for reads and one for writes
343 struct request_list rq
;
345 request_fn_proc
*request_fn
;
346 merge_request_fn
*back_merge_fn
;
347 merge_request_fn
*front_merge_fn
;
348 merge_requests_fn
*merge_requests_fn
;
349 make_request_fn
*make_request_fn
;
350 prep_rq_fn
*prep_rq_fn
;
351 unplug_fn
*unplug_fn
;
352 merge_bvec_fn
*merge_bvec_fn
;
353 activity_fn
*activity_fn
;
354 issue_flush_fn
*issue_flush_fn
;
355 prepare_flush_fn
*prepare_flush_fn
;
356 softirq_done_fn
*softirq_done_fn
;
359 * Dispatch queue sorting
362 struct request
*boundary_rq
;
365 * Auto-unplugging state
367 struct timer_list unplug_timer
;
368 int unplug_thresh
; /* After this many requests */
369 unsigned long unplug_delay
; /* After this many jiffies */
370 struct work_struct unplug_work
;
372 struct backing_dev_info backing_dev_info
;
375 * The queue owner gets to use this for whatever they like.
376 * ll_rw_blk doesn't touch it.
383 * queue needs bounce pages for pages above this limit
385 unsigned long bounce_pfn
;
389 * various queue flags, see QUEUE_* below
391 unsigned long queue_flags
;
394 * protects queue structures from reentrancy. ->__queue_lock should
395 * _never_ be used directly, it is queue private. always use
398 spinlock_t __queue_lock
;
399 spinlock_t
*queue_lock
;
409 unsigned long nr_requests
; /* Max # of requests */
410 unsigned int nr_congestion_on
;
411 unsigned int nr_congestion_off
;
412 unsigned int nr_batching
;
414 unsigned int max_sectors
;
415 unsigned int max_hw_sectors
;
416 unsigned short max_phys_segments
;
417 unsigned short max_hw_segments
;
418 unsigned short hardsect_size
;
419 unsigned int max_segment_size
;
421 unsigned long seg_boundary_mask
;
422 unsigned int dma_alignment
;
424 struct blk_queue_tag
*queue_tags
;
426 unsigned int nr_sorted
;
427 unsigned int in_flight
;
432 unsigned int sg_timeout
;
433 unsigned int sg_reserved_size
;
435 #ifdef CONFIG_BLK_DEV_IO_TRACE
436 struct blk_trace
*blk_trace
;
439 * reserved for flush operations
441 unsigned int ordered
, next_ordered
, ordseq
;
442 int orderr
, ordcolor
;
443 struct request pre_flush_rq
, bar_rq
, post_flush_rq
;
444 struct request
*orig_bar_rq
;
445 unsigned int bi_size
;
447 struct mutex sysfs_lock
;
450 #define RQ_INACTIVE (-1)
453 #define QUEUE_FLAG_CLUSTER 0 /* cluster several segments into 1 */
454 #define QUEUE_FLAG_QUEUED 1 /* uses generic tag queueing */
455 #define QUEUE_FLAG_STOPPED 2 /* queue is stopped */
456 #define QUEUE_FLAG_READFULL 3 /* write queue has been filled */
457 #define QUEUE_FLAG_WRITEFULL 4 /* read queue has been filled */
458 #define QUEUE_FLAG_DEAD 5 /* queue being torn down */
459 #define QUEUE_FLAG_REENTER 6 /* Re-entrancy avoidance */
460 #define QUEUE_FLAG_PLUGGED 7 /* queue is plugged */
461 #define QUEUE_FLAG_ELVSWITCH 8 /* don't use elevator, just do FIFO */
465 * Hardbarrier is supported with one of the following methods.
467 * NONE : hardbarrier unsupported
468 * DRAIN : ordering by draining is enough
469 * DRAIN_FLUSH : ordering by draining w/ pre and post flushes
470 * DRAIN_FUA : ordering by draining w/ pre flush and FUA write
471 * TAG : ordering by tag is enough
472 * TAG_FLUSH : ordering by tag w/ pre and post flushes
473 * TAG_FUA : ordering by tag w/ pre flush and FUA write
475 QUEUE_ORDERED_NONE
= 0x00,
476 QUEUE_ORDERED_DRAIN
= 0x01,
477 QUEUE_ORDERED_TAG
= 0x02,
479 QUEUE_ORDERED_PREFLUSH
= 0x10,
480 QUEUE_ORDERED_POSTFLUSH
= 0x20,
481 QUEUE_ORDERED_FUA
= 0x40,
483 QUEUE_ORDERED_DRAIN_FLUSH
= QUEUE_ORDERED_DRAIN
|
484 QUEUE_ORDERED_PREFLUSH
| QUEUE_ORDERED_POSTFLUSH
,
485 QUEUE_ORDERED_DRAIN_FUA
= QUEUE_ORDERED_DRAIN
|
486 QUEUE_ORDERED_PREFLUSH
| QUEUE_ORDERED_FUA
,
487 QUEUE_ORDERED_TAG_FLUSH
= QUEUE_ORDERED_TAG
|
488 QUEUE_ORDERED_PREFLUSH
| QUEUE_ORDERED_POSTFLUSH
,
489 QUEUE_ORDERED_TAG_FUA
= QUEUE_ORDERED_TAG
|
490 QUEUE_ORDERED_PREFLUSH
| QUEUE_ORDERED_FUA
,
493 * Ordered operation sequence
495 QUEUE_ORDSEQ_STARTED
= 0x01, /* flushing in progress */
496 QUEUE_ORDSEQ_DRAIN
= 0x02, /* waiting for the queue to be drained */
497 QUEUE_ORDSEQ_PREFLUSH
= 0x04, /* pre-flushing in progress */
498 QUEUE_ORDSEQ_BAR
= 0x08, /* original barrier req in progress */
499 QUEUE_ORDSEQ_POSTFLUSH
= 0x10, /* post-flushing in progress */
500 QUEUE_ORDSEQ_DONE
= 0x20,
503 #define blk_queue_plugged(q) test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
504 #define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
505 #define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
506 #define blk_queue_flushing(q) ((q)->ordseq)
508 #define blk_fs_request(rq) ((rq)->cmd_type == REQ_TYPE_FS)
509 #define blk_pc_request(rq) ((rq)->cmd_type == REQ_TYPE_BLOCK_PC)
510 #define blk_special_request(rq) ((rq)->cmd_type == REQ_TYPE_SPECIAL)
511 #define blk_sense_request(rq) ((rq)->cmd_type == REQ_TYPE_SENSE)
513 #define blk_noretry_request(rq) ((rq)->cmd_flags & REQ_FAILFAST)
514 #define blk_rq_started(rq) ((rq)->cmd_flags & REQ_STARTED)
516 #define blk_account_rq(rq) (blk_rq_started(rq) && blk_fs_request(rq))
518 #define blk_pm_suspend_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND)
519 #define blk_pm_resume_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_RESUME)
520 #define blk_pm_request(rq) \
521 (blk_pm_suspend_request(rq) || blk_pm_resume_request(rq))
523 #define blk_sorted_rq(rq) ((rq)->cmd_flags & REQ_SORTED)
524 #define blk_barrier_rq(rq) ((rq)->cmd_flags & REQ_HARDBARRIER)
525 #define blk_fua_rq(rq) ((rq)->cmd_flags & REQ_FUA)
527 #define list_entry_rq(ptr) list_entry((ptr), struct request, queuelist)
529 #define rq_data_dir(rq) ((rq)->cmd_flags & 1)
531 static inline int blk_queue_full(struct request_queue
*q
, int rw
)
534 return test_bit(QUEUE_FLAG_READFULL
, &q
->queue_flags
);
535 return test_bit(QUEUE_FLAG_WRITEFULL
, &q
->queue_flags
);
538 static inline void blk_set_queue_full(struct request_queue
*q
, int rw
)
541 set_bit(QUEUE_FLAG_READFULL
, &q
->queue_flags
);
543 set_bit(QUEUE_FLAG_WRITEFULL
, &q
->queue_flags
);
546 static inline void blk_clear_queue_full(struct request_queue
*q
, int rw
)
549 clear_bit(QUEUE_FLAG_READFULL
, &q
->queue_flags
);
551 clear_bit(QUEUE_FLAG_WRITEFULL
, &q
->queue_flags
);
556 * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
557 * it already be started by driver.
559 #define RQ_NOMERGE_FLAGS \
560 (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER)
561 #define rq_mergeable(rq) \
562 (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && blk_fs_request((rq)))
565 * noop, requests are automagically marked as active/inactive by I/O
566 * scheduler -- see elv_next_request
568 #define blk_queue_headactive(q, head_active)
571 * q->prep_rq_fn return values
573 #define BLKPREP_OK 0 /* serve it */
574 #define BLKPREP_KILL 1 /* fatal error, kill */
575 #define BLKPREP_DEFER 2 /* leave on queue */
577 extern unsigned long blk_max_low_pfn
, blk_max_pfn
;
580 * standard bounce addresses:
582 * BLK_BOUNCE_HIGH : bounce all highmem pages
583 * BLK_BOUNCE_ANY : don't bounce anything
584 * BLK_BOUNCE_ISA : bounce pages above ISA DMA boundary
586 #define BLK_BOUNCE_HIGH ((u64)blk_max_low_pfn << PAGE_SHIFT)
587 #define BLK_BOUNCE_ANY ((u64)blk_max_pfn << PAGE_SHIFT)
588 #define BLK_BOUNCE_ISA (ISA_DMA_THRESHOLD)
591 extern int init_emergency_isa_pool(void);
592 extern void blk_queue_bounce(request_queue_t
*q
, struct bio
**bio
);
594 static inline int init_emergency_isa_pool(void)
598 static inline void blk_queue_bounce(request_queue_t
*q
, struct bio
**bio
)
601 #endif /* CONFIG_MMU */
603 #define rq_for_each_bio(_bio, rq) \
605 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
609 unsigned block_size_bits
;
612 extern int blk_register_queue(struct gendisk
*disk
);
613 extern void blk_unregister_queue(struct gendisk
*disk
);
614 extern void register_disk(struct gendisk
*dev
);
615 extern void generic_make_request(struct bio
*bio
);
616 extern void blk_put_request(struct request
*);
617 extern void __blk_put_request(request_queue_t
*, struct request
*);
618 extern void blk_end_sync_rq(struct request
*rq
, int error
);
619 extern struct request
*blk_get_request(request_queue_t
*, int, gfp_t
);
620 extern void blk_insert_request(request_queue_t
*, struct request
*, int, void *);
621 extern void blk_requeue_request(request_queue_t
*, struct request
*);
622 extern void blk_plug_device(request_queue_t
*);
623 extern int blk_remove_plug(request_queue_t
*);
624 extern void blk_recount_segments(request_queue_t
*, struct bio
*);
625 extern int scsi_cmd_ioctl(struct file
*, struct gendisk
*, unsigned int, void __user
*);
626 extern int sg_scsi_ioctl(struct file
*, struct request_queue
*,
627 struct gendisk
*, struct scsi_ioctl_command __user
*);
628 extern void blk_start_queue(request_queue_t
*q
);
629 extern void blk_stop_queue(request_queue_t
*q
);
630 extern void blk_sync_queue(struct request_queue
*q
);
631 extern void __blk_stop_queue(request_queue_t
*q
);
632 extern void blk_run_queue(request_queue_t
*);
633 extern void blk_queue_activity_fn(request_queue_t
*, activity_fn
*, void *);
634 extern int blk_rq_map_user(request_queue_t
*, struct request
*, void __user
*, unsigned int);
635 extern int blk_rq_unmap_user(struct bio
*, unsigned int);
636 extern int blk_rq_map_kern(request_queue_t
*, struct request
*, void *, unsigned int, gfp_t
);
637 extern int blk_rq_map_user_iov(request_queue_t
*, struct request
*, struct sg_iovec
*, int);
638 extern int blk_execute_rq(request_queue_t
*, struct gendisk
*,
639 struct request
*, int);
640 extern void blk_execute_rq_nowait(request_queue_t
*, struct gendisk
*,
641 struct request
*, int, rq_end_io_fn
*);
643 static inline request_queue_t
*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 * end_request() and friends. Must be called with the request queue spinlock
663 * acquired. All functions called within end_request() _must_be_ atomic.
665 * Several drivers define their own end_request and call
666 * end_that_request_first() and end_that_request_last()
667 * for parts of the original function. This prevents
668 * code duplication in drivers.
670 extern int end_that_request_first(struct request
*, int, int);
671 extern int end_that_request_chunk(struct request
*, int, int);
672 extern void end_that_request_last(struct request
*, int);
673 extern void end_request(struct request
*req
, int uptodate
);
674 extern void blk_complete_request(struct request
*);
676 static inline int rq_all_done(struct request
*rq
, unsigned int nr_bytes
)
678 if (blk_fs_request(rq
))
679 return (nr_bytes
>= (rq
->hard_nr_sectors
<< 9));
680 else if (blk_pc_request(rq
))
681 return nr_bytes
>= rq
->data_len
;
687 * end_that_request_first/chunk() takes an uptodate argument. we account
688 * any value <= as an io error. 0 means -EIO for compatability reasons,
689 * any other < 0 value is the direct error type. An uptodate value of
690 * 1 indicates successful io completion
692 #define end_io_error(uptodate) (unlikely((uptodate) <= 0))
694 static inline void blkdev_dequeue_request(struct request
*req
)
696 elv_dequeue_request(req
->q
, req
);
700 * This should be in elevator.h, but that requires pulling in rq and q
702 static inline void elv_dispatch_add_tail(struct request_queue
*q
,
705 if (q
->last_merge
== rq
)
706 q
->last_merge
= NULL
;
709 q
->end_sector
= rq_end_sector(rq
);
711 list_add_tail(&rq
->queuelist
, &q
->queue_head
);
715 * Access functions for manipulating queue properties
717 extern request_queue_t
*blk_init_queue_node(request_fn_proc
*rfn
,
718 spinlock_t
*lock
, int node_id
);
719 extern request_queue_t
*blk_init_queue(request_fn_proc
*, spinlock_t
*);
720 extern void blk_cleanup_queue(request_queue_t
*);
721 extern void blk_queue_make_request(request_queue_t
*, make_request_fn
*);
722 extern void blk_queue_bounce_limit(request_queue_t
*, u64
);
723 extern void blk_queue_max_sectors(request_queue_t
*, unsigned int);
724 extern void blk_queue_max_phys_segments(request_queue_t
*, unsigned short);
725 extern void blk_queue_max_hw_segments(request_queue_t
*, unsigned short);
726 extern void blk_queue_max_segment_size(request_queue_t
*, unsigned int);
727 extern void blk_queue_hardsect_size(request_queue_t
*, unsigned short);
728 extern void blk_queue_stack_limits(request_queue_t
*t
, request_queue_t
*b
);
729 extern void blk_queue_segment_boundary(request_queue_t
*, unsigned long);
730 extern void blk_queue_prep_rq(request_queue_t
*, prep_rq_fn
*pfn
);
731 extern void blk_queue_merge_bvec(request_queue_t
*, merge_bvec_fn
*);
732 extern void blk_queue_dma_alignment(request_queue_t
*, int);
733 extern void blk_queue_softirq_done(request_queue_t
*, softirq_done_fn
*);
734 extern struct backing_dev_info
*blk_get_backing_dev_info(struct block_device
*bdev
);
735 extern int blk_queue_ordered(request_queue_t
*, unsigned, prepare_flush_fn
*);
736 extern void blk_queue_issue_flush_fn(request_queue_t
*, issue_flush_fn
*);
737 extern int blk_do_ordered(request_queue_t
*, struct request
**);
738 extern unsigned blk_ordered_cur_seq(request_queue_t
*);
739 extern unsigned blk_ordered_req_seq(struct request
*);
740 extern void blk_ordered_complete_seq(request_queue_t
*, unsigned, int);
742 extern int blk_rq_map_sg(request_queue_t
*, struct request
*, struct scatterlist
*);
743 extern void blk_dump_rq_flags(struct request
*, char *);
744 extern void generic_unplug_device(request_queue_t
*);
745 extern void __generic_unplug_device(request_queue_t
*);
746 extern long nr_blockdev_pages(void);
748 int blk_get_queue(request_queue_t
*);
749 request_queue_t
*blk_alloc_queue(gfp_t
);
750 request_queue_t
*blk_alloc_queue_node(gfp_t
, int);
751 extern void blk_put_queue(request_queue_t
*);
756 #define blk_queue_tag_depth(q) ((q)->queue_tags->busy)
757 #define blk_queue_tag_queue(q) ((q)->queue_tags->busy < (q)->queue_tags->max_depth)
758 #define blk_rq_tagged(rq) ((rq)->cmd_flags & REQ_QUEUED)
759 extern int blk_queue_start_tag(request_queue_t
*, struct request
*);
760 extern struct request
*blk_queue_find_tag(request_queue_t
*, int);
761 extern void blk_queue_end_tag(request_queue_t
*, struct request
*);
762 extern int blk_queue_init_tags(request_queue_t
*, int, struct blk_queue_tag
*);
763 extern void blk_queue_free_tags(request_queue_t
*);
764 extern int blk_queue_resize_tags(request_queue_t
*, int);
765 extern void blk_queue_invalidate_tags(request_queue_t
*);
766 extern long blk_congestion_wait(int rw
, long timeout
);
767 extern struct blk_queue_tag
*blk_init_tags(int);
768 extern void blk_free_tags(struct blk_queue_tag
*);
769 extern void blk_congestion_end(int rw
);
771 extern void blk_rq_bio_prep(request_queue_t
*, struct request
*, struct bio
*);
772 extern int blkdev_issue_flush(struct block_device
*, sector_t
*);
774 #define MAX_PHYS_SEGMENTS 128
775 #define MAX_HW_SEGMENTS 128
776 #define SAFE_MAX_SECTORS 255
777 #define BLK_DEF_MAX_SECTORS 1024
779 #define MAX_SEGMENT_SIZE 65536
781 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
783 static inline int queue_hardsect_size(request_queue_t
*q
)
787 if (q
&& q
->hardsect_size
)
788 retval
= q
->hardsect_size
;
793 static inline int bdev_hardsect_size(struct block_device
*bdev
)
795 return queue_hardsect_size(bdev_get_queue(bdev
));
798 static inline int queue_dma_alignment(request_queue_t
*q
)
802 if (q
&& q
->dma_alignment
)
803 retval
= q
->dma_alignment
;
808 static inline int bdev_dma_aligment(struct block_device
*bdev
)
810 return queue_dma_alignment(bdev_get_queue(bdev
));
813 #define blk_finished_io(nsects) do { } while (0)
814 #define blk_started_io(nsects) do { } while (0)
816 /* assumes size > 256 */
817 static inline unsigned int blksize_bits(unsigned int size
)
819 unsigned int bits
= 8;
823 } while (size
> 256);
827 static inline unsigned int block_size(struct block_device
*bdev
)
829 return bdev
->bd_block_size
;
832 typedef struct {struct page
*v
;} Sector
;
834 unsigned char *read_dev_sector(struct block_device
*, sector_t
, Sector
*);
836 static inline void put_dev_sector(Sector p
)
838 page_cache_release(p
.v
);
842 int kblockd_schedule_work(struct work_struct
*work
);
843 void kblockd_flush(void);
846 # include <asm/div64.h>
847 # define sector_div(a, b) do_div(a, b)
849 # define sector_div(n, b)( \
859 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
860 MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
861 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
862 MODULE_ALIAS("block-major-" __stringify(major) "-*")