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>
20 # include <asm/div64.h>
21 # define sector_div(a, b) do_div(a, b)
23 # define sector_div(n, b)( \
35 struct scsi_ioctl_command;
38 typedef struct request_queue request_queue_t;
39 struct elevator_queue;
40 typedef struct elevator_queue elevator_t;
41 struct request_pm_state;
44 #define BLKDEV_MIN_RQ 4
45 #define BLKDEV_MAX_RQ 128 /* Default maximum */
48 * This is the per-process anticipatory I/O scheduler state.
50 struct as_io_context {
53 void (*dtor)(struct as_io_context *aic); /* destructor */
54 void (*exit)(struct as_io_context *aic); /* called on task exit */
57 atomic_t nr_queued; /* queued reads & sync writes */
58 atomic_t nr_dispatched; /* number of requests gone to the drivers */
60 /* IO History tracking */
62 unsigned long last_end_request;
63 unsigned long ttime_total;
64 unsigned long ttime_samples;
65 unsigned long ttime_mean;
67 unsigned int seek_samples;
68 sector_t last_request_pos;
74 struct cfq_io_context {
75 struct rb_node rb_node;
78 struct cfq_queue *cfqq[2];
80 struct io_context *ioc;
82 unsigned long last_end_request;
83 sector_t last_request_pos;
84 unsigned long last_queue;
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,
162 * For request of type REQ_TYPE_LINUX_BLOCK, rq->cmd[0] is the opcode being
163 * sent down (similar to how REQ_TYPE_BLOCK_PC means that ->cmd[] holds a
166 * 0x00 -> 0x3f are driver private, to be used for whatever purpose they need,
167 * typically to differentiate REQ_TYPE_SPECIAL requests.
172 * just examples for now
174 REQ_LB_OP_EJECT = 0x40, /* eject request */
175 REQ_LB_OP_FLUSH = 0x41, /* flush device */
179 * request type modified bits. first three bits match BIO_RW* bits, important
182 __REQ_RW, /* not set, read. set, write */
183 __REQ_FAILFAST, /* no low level driver retries */
184 __REQ_SORTED, /* elevator knows about this request */
185 __REQ_SOFTBARRIER, /* may not be passed by ioscheduler */
186 __REQ_HARDBARRIER, /* may not be passed by drive either */
187 __REQ_FUA, /* forced unit access */
188 __REQ_NOMERGE, /* don't touch this for merging */
189 __REQ_STARTED, /* drive already may have started this one */
190 __REQ_DONTPREP, /* don't call prep for this one */
191 __REQ_QUEUED, /* uses queueing */
192 __REQ_ELVPRIV, /* elevator private data attached */
193 __REQ_FAILED, /* set if the request failed */
194 __REQ_QUIET, /* don't worry about errors */
195 __REQ_PREEMPT, /* set for "ide_preempt" requests */
196 __REQ_ORDERED_COLOR, /* is before or after barrier */
197 __REQ_RW_SYNC, /* request is sync (O_DIRECT) */
198 __REQ_ALLOCED, /* request came from our alloc pool */
199 __REQ_RW_META, /* metadata io request */
200 __REQ_NR_BITS, /* stops here */
203 #define REQ_RW (1 << __REQ_RW)
204 #define REQ_FAILFAST (1 << __REQ_FAILFAST)
205 #define REQ_SORTED (1 << __REQ_SORTED)
206 #define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER)
207 #define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER)
208 #define REQ_FUA (1 << __REQ_FUA)
209 #define REQ_NOMERGE (1 << __REQ_NOMERGE)
210 #define REQ_STARTED (1 << __REQ_STARTED)
211 #define REQ_DONTPREP (1 << __REQ_DONTPREP)
212 #define REQ_QUEUED (1 << __REQ_QUEUED)
213 #define REQ_ELVPRIV (1 << __REQ_ELVPRIV)
214 #define REQ_FAILED (1 << __REQ_FAILED)
215 #define REQ_QUIET (1 << __REQ_QUIET)
216 #define REQ_PREEMPT (1 << __REQ_PREEMPT)
217 #define REQ_ORDERED_COLOR (1 << __REQ_ORDERED_COLOR)
218 #define REQ_RW_SYNC (1 << __REQ_RW_SYNC)
219 #define REQ_ALLOCED (1 << __REQ_ALLOCED)
220 #define REQ_RW_META (1 << __REQ_RW_META)
222 #define BLK_MAX_CDB 16
225 * try to put the fields that are referenced together in the same cacheline
228 struct list_head queuelist;
229 struct list_head donelist;
233 unsigned int cmd_flags;
234 enum rq_cmd_type_bits cmd_type;
236 /* Maintain bio traversal state for part by part I/O submission.
237 * hard_* are block layer internals, no driver should touch them!
240 sector_t sector; /* next sector to submit */
241 sector_t hard_sector; /* next sector to complete */
242 unsigned long nr_sectors; /* no. of sectors left to submit */
243 unsigned long hard_nr_sectors; /* no. of sectors left to complete */
244 /* no. of sectors left to submit in the current segment */
245 unsigned int current_nr_sectors;
247 /* no. of sectors left to complete in the current segment */
248 unsigned int hard_cur_sectors;
253 struct hlist_node hash; /* merge hash */
255 * The rb_node is only used inside the io scheduler, requests
256 * are pruned when moved to the dispatch queue. So let the
257 * completion_data share space with the rb_node.
260 struct rb_node rb_node; /* sort/lookup */
261 void *completion_data;
265 * two pointers are available for the IO schedulers, if they need
266 * more they have to dynamically allocate it.
268 void *elevator_private;
269 void *elevator_private2;
271 struct gendisk *rq_disk;
272 unsigned long start_time;
274 /* Number of scatter-gather DMA addr+len pairs after
275 * physical address coalescing is performed.
277 unsigned short nr_phys_segments;
279 /* Number of scatter-gather addr+len pairs after
280 * physical and DMA remapping hardware coalescing is performed.
281 * This is the number of scatter-gather entries the driver
282 * will actually have to deal with after DMA mapping is done.
284 unsigned short nr_hw_segments;
286 unsigned short ioprio;
297 * when request is used as a packet command carrier
299 unsigned int cmd_len;
300 unsigned char cmd[BLK_MAX_CDB];
302 unsigned int data_len;
303 unsigned int sense_len;
307 unsigned int timeout;
311 * completion callback.
313 rq_end_io_fn *end_io;
318 * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
319 * requests. Some step values could eventually be made generic.
321 struct request_pm_state
323 /* PM state machine step value, currently driver specific */
325 /* requested PM state value (S1, S2, S3, S4, ...) */
327 void* data; /* for driver use */
330 #include <linux/elevator.h>
332 typedef int (merge_request_fn) (request_queue_t *, struct request *,
334 typedef int (merge_requests_fn) (request_queue_t *, struct request *,
336 typedef void (request_fn_proc) (request_queue_t *q);
337 typedef int (make_request_fn) (request_queue_t *q, struct bio *bio);
338 typedef int (prep_rq_fn) (request_queue_t *, struct request *);
339 typedef void (unplug_fn) (request_queue_t *);
342 typedef int (merge_bvec_fn) (request_queue_t *, struct bio *, struct bio_vec *);
343 typedef void (activity_fn) (void *data, int rw);
344 typedef int (issue_flush_fn) (request_queue_t *, struct gendisk *, sector_t *);
345 typedef void (prepare_flush_fn) (request_queue_t *, struct request *);
346 typedef void (softirq_done_fn)(struct request *);
348 enum blk_queue_state {
353 struct blk_queue_tag {
354 struct request **tag_index; /* map of busy tags */
355 unsigned long *tag_map; /* bit map of free/busy tags */
356 struct list_head busy_list; /* fifo list of busy tags */
357 int busy; /* current depth */
358 int max_depth; /* what we will send to device */
359 int real_max_depth; /* what the array can hold */
360 atomic_t refcnt; /* map can be shared */
366 * Together with queue_head for cacheline sharing
368 struct list_head queue_head;
369 struct request *last_merge;
370 elevator_t *elevator;
373 * the queue request freelist, one for reads and one for writes
375 struct request_list rq;
377 request_fn_proc *request_fn;
378 merge_request_fn *back_merge_fn;
379 merge_request_fn *front_merge_fn;
380 merge_requests_fn *merge_requests_fn;
381 make_request_fn *make_request_fn;
382 prep_rq_fn *prep_rq_fn;
383 unplug_fn *unplug_fn;
384 merge_bvec_fn *merge_bvec_fn;
385 activity_fn *activity_fn;
386 issue_flush_fn *issue_flush_fn;
387 prepare_flush_fn *prepare_flush_fn;
388 softirq_done_fn *softirq_done_fn;
391 * Dispatch queue sorting
394 struct request *boundary_rq;
397 * Auto-unplugging state
399 struct timer_list unplug_timer;
400 int unplug_thresh; /* After this many requests */
401 unsigned long unplug_delay; /* After this many jiffies */
402 struct work_struct unplug_work;
404 struct backing_dev_info backing_dev_info;
407 * The queue owner gets to use this for whatever they like.
408 * ll_rw_blk doesn't touch it.
415 * queue needs bounce pages for pages above this limit
417 unsigned long bounce_pfn;
421 * various queue flags, see QUEUE_* below
423 unsigned long queue_flags;
426 * protects queue structures from reentrancy. ->__queue_lock should
427 * _never_ be used directly, it is queue private. always use
430 spinlock_t __queue_lock;
431 spinlock_t *queue_lock;
441 unsigned long nr_requests; /* Max # of requests */
442 unsigned int nr_congestion_on;
443 unsigned int nr_congestion_off;
444 unsigned int nr_batching;
446 unsigned int max_sectors;
447 unsigned int max_hw_sectors;
448 unsigned short max_phys_segments;
449 unsigned short max_hw_segments;
450 unsigned short hardsect_size;
451 unsigned int max_segment_size;
453 unsigned long seg_boundary_mask;
454 unsigned int dma_alignment;
456 struct blk_queue_tag *queue_tags;
458 unsigned int nr_sorted;
459 unsigned int in_flight;
464 unsigned int sg_timeout;
465 unsigned int sg_reserved_size;
467 #ifdef CONFIG_BLK_DEV_IO_TRACE
468 struct blk_trace *blk_trace;
471 * reserved for flush operations
473 unsigned int ordered, next_ordered, ordseq;
474 int orderr, ordcolor;
475 struct request pre_flush_rq, bar_rq, post_flush_rq;
476 struct request *orig_bar_rq;
477 unsigned int bi_size;
479 struct mutex sysfs_lock;
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 */
494 * Hardbarrier is supported with one of the following methods.
496 * NONE : hardbarrier unsupported
497 * DRAIN : ordering by draining is enough
498 * DRAIN_FLUSH : ordering by draining w/ pre and post flushes
499 * DRAIN_FUA : ordering by draining w/ pre flush and FUA write
500 * TAG : ordering by tag is enough
501 * TAG_FLUSH : ordering by tag w/ pre and post flushes
502 * TAG_FUA : ordering by tag w/ pre flush and FUA write
504 QUEUE_ORDERED_NONE = 0x00,
505 QUEUE_ORDERED_DRAIN = 0x01,
506 QUEUE_ORDERED_TAG = 0x02,
508 QUEUE_ORDERED_PREFLUSH = 0x10,
509 QUEUE_ORDERED_POSTFLUSH = 0x20,
510 QUEUE_ORDERED_FUA = 0x40,
512 QUEUE_ORDERED_DRAIN_FLUSH = QUEUE_ORDERED_DRAIN |
513 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
514 QUEUE_ORDERED_DRAIN_FUA = QUEUE_ORDERED_DRAIN |
515 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
516 QUEUE_ORDERED_TAG_FLUSH = QUEUE_ORDERED_TAG |
517 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
518 QUEUE_ORDERED_TAG_FUA = QUEUE_ORDERED_TAG |
519 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
522 * Ordered operation sequence
524 QUEUE_ORDSEQ_STARTED = 0x01, /* flushing in progress */
525 QUEUE_ORDSEQ_DRAIN = 0x02, /* waiting for the queue to be drained */
526 QUEUE_ORDSEQ_PREFLUSH = 0x04, /* pre-flushing in progress */
527 QUEUE_ORDSEQ_BAR = 0x08, /* original barrier req in progress */
528 QUEUE_ORDSEQ_POSTFLUSH = 0x10, /* post-flushing in progress */
529 QUEUE_ORDSEQ_DONE = 0x20,
532 #define blk_queue_plugged(q) test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
533 #define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
534 #define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
535 #define blk_queue_flushing(q) ((q)->ordseq)
537 #define blk_fs_request(rq) ((rq)->cmd_type == REQ_TYPE_FS)
538 #define blk_pc_request(rq) ((rq)->cmd_type == REQ_TYPE_BLOCK_PC)
539 #define blk_special_request(rq) ((rq)->cmd_type == REQ_TYPE_SPECIAL)
540 #define blk_sense_request(rq) ((rq)->cmd_type == REQ_TYPE_SENSE)
542 #define blk_noretry_request(rq) ((rq)->cmd_flags & REQ_FAILFAST)
543 #define blk_rq_started(rq) ((rq)->cmd_flags & REQ_STARTED)
545 #define blk_account_rq(rq) (blk_rq_started(rq) && blk_fs_request(rq))
547 #define blk_pm_suspend_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND)
548 #define blk_pm_resume_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_RESUME)
549 #define blk_pm_request(rq) \
550 (blk_pm_suspend_request(rq) || blk_pm_resume_request(rq))
552 #define blk_sorted_rq(rq) ((rq)->cmd_flags & REQ_SORTED)
553 #define blk_barrier_rq(rq) ((rq)->cmd_flags & REQ_HARDBARRIER)
554 #define blk_fua_rq(rq) ((rq)->cmd_flags & REQ_FUA)
556 #define list_entry_rq(ptr) list_entry((ptr), struct request, queuelist)
558 #define rq_data_dir(rq) ((rq)->cmd_flags & 1)
561 * We regard a request as sync, if it's a READ or a SYNC write.
563 #define rq_is_sync(rq) (rq_data_dir((rq)) == READ || (rq)->cmd_flags & REQ_RW_SYNC)
564 #define rq_is_meta(rq) ((rq)->cmd_flags & REQ_RW_META)
566 static inline int blk_queue_full(struct request_queue *q, int rw)
569 return test_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
570 return test_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
573 static inline void blk_set_queue_full(struct request_queue *q, int rw)
576 set_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
578 set_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
581 static inline void blk_clear_queue_full(struct request_queue *q, int rw)
584 clear_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
586 clear_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
591 * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
592 * it already be started by driver.
594 #define RQ_NOMERGE_FLAGS \
595 (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER)
596 #define rq_mergeable(rq) \
597 (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && blk_fs_request((rq)))
600 * q->prep_rq_fn return values
602 #define BLKPREP_OK 0 /* serve it */
603 #define BLKPREP_KILL 1 /* fatal error, kill */
604 #define BLKPREP_DEFER 2 /* leave on queue */
606 extern unsigned long blk_max_low_pfn, blk_max_pfn;
609 * standard bounce addresses:
611 * BLK_BOUNCE_HIGH : bounce all highmem pages
612 * BLK_BOUNCE_ANY : don't bounce anything
613 * BLK_BOUNCE_ISA : bounce pages above ISA DMA boundary
615 #define BLK_BOUNCE_HIGH ((u64)blk_max_low_pfn << PAGE_SHIFT)
616 #define BLK_BOUNCE_ANY ((u64)blk_max_pfn << PAGE_SHIFT)
617 #define BLK_BOUNCE_ISA (ISA_DMA_THRESHOLD)
620 extern int init_emergency_isa_pool(void);
621 extern void blk_queue_bounce(request_queue_t *q, struct bio **bio);
623 static inline int init_emergency_isa_pool(void)
627 static inline void blk_queue_bounce(request_queue_t *q, struct bio **bio)
630 #endif /* CONFIG_MMU */
632 #define rq_for_each_bio(_bio, rq) \
634 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
636 extern int blk_register_queue(struct gendisk *disk);
637 extern void blk_unregister_queue(struct gendisk *disk);
638 extern void register_disk(struct gendisk *dev);
639 extern void generic_make_request(struct bio *bio);
640 extern void blk_put_request(struct request *);
641 extern void __blk_put_request(request_queue_t *, struct request *);
642 extern void blk_end_sync_rq(struct request *rq, int error);
643 extern struct request *blk_get_request(request_queue_t *, int, gfp_t);
644 extern void blk_insert_request(request_queue_t *, struct request *, int, void *);
645 extern void blk_requeue_request(request_queue_t *, struct request *);
646 extern void blk_plug_device(request_queue_t *);
647 extern int blk_remove_plug(request_queue_t *);
648 extern void blk_recount_segments(request_queue_t *, struct bio *);
649 extern int scsi_cmd_ioctl(struct file *, struct gendisk *, unsigned int, void __user *);
650 extern int sg_scsi_ioctl(struct file *, struct request_queue *,
651 struct gendisk *, struct scsi_ioctl_command __user *);
652 extern void blk_start_queue(request_queue_t *q);
653 extern void blk_stop_queue(request_queue_t *q);
654 extern void blk_sync_queue(struct request_queue *q);
655 extern void __blk_stop_queue(request_queue_t *q);
656 extern void blk_run_queue(request_queue_t *);
657 extern void blk_start_queueing(request_queue_t *);
658 extern void blk_queue_activity_fn(request_queue_t *, activity_fn *, void *);
659 extern int blk_rq_map_user(request_queue_t *, struct request *, void __user *, unsigned int);
660 extern int blk_rq_unmap_user(struct bio *, unsigned int);
661 extern int blk_rq_map_kern(request_queue_t *, struct request *, void *, unsigned int, gfp_t);
662 extern int blk_rq_map_user_iov(request_queue_t *, struct request *, struct sg_iovec *, int);
663 extern int blk_execute_rq(request_queue_t *, struct gendisk *,
664 struct request *, int);
665 extern void blk_execute_rq_nowait(request_queue_t *, struct gendisk *,
666 struct request *, int, rq_end_io_fn *);
668 static inline request_queue_t *bdev_get_queue(struct block_device *bdev)
670 return bdev->bd_disk->queue;
673 static inline void blk_run_backing_dev(struct backing_dev_info *bdi,
676 if (bdi && bdi->unplug_io_fn)
677 bdi->unplug_io_fn(bdi, page);
680 static inline void blk_run_address_space(struct address_space *mapping)
683 blk_run_backing_dev(mapping->backing_dev_info, NULL);
687 * end_request() and friends. Must be called with the request queue spinlock
688 * acquired. All functions called within end_request() _must_be_ atomic.
690 * Several drivers define their own end_request and call
691 * end_that_request_first() and end_that_request_last()
692 * for parts of the original function. This prevents
693 * code duplication in drivers.
695 extern int end_that_request_first(struct request *, int, int);
696 extern int end_that_request_chunk(struct request *, int, int);
697 extern void end_that_request_last(struct request *, int);
698 extern void end_request(struct request *req, int uptodate);
699 extern void blk_complete_request(struct request *);
702 * end_that_request_first/chunk() takes an uptodate argument. we account
703 * any value <= as an io error. 0 means -EIO for compatability reasons,
704 * any other < 0 value is the direct error type. An uptodate value of
705 * 1 indicates successful io completion
707 #define end_io_error(uptodate) (unlikely((uptodate) <= 0))
709 static inline void blkdev_dequeue_request(struct request *req)
711 elv_dequeue_request(req->q, req);
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 /* assumes size > 256 */
809 static inline unsigned int blksize_bits(unsigned int size)
811 unsigned int bits = 8;
815 } while (size > 256);
819 static inline unsigned int block_size(struct block_device *bdev)
821 return bdev->bd_block_size;
824 typedef struct {struct page *v;} Sector;
826 unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
828 static inline void put_dev_sector(Sector p)
830 page_cache_release(p.v);
834 int kblockd_schedule_work(struct work_struct *work);
835 void kblockd_flush(void);
837 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
838 MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
839 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
840 MODULE_ALIAS("block-major-" __stringify(major) "-*")
843 #else /* CONFIG_BLOCK */
845 * stubs for when the block layer is configured out
847 #define buffer_heads_over_limit 0
849 static inline long blk_congestion_wait(int rw, long timeout)
854 static inline long nr_blockdev_pages(void)
859 static inline void exit_io_context(void) {}
861 #endif /* CONFIG_BLOCK */