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];
123 #define BLK_MAX_CDB 16
126 * try to put the fields that are referenced together in the same cacheline
129 struct list_head queuelist;
130 struct list_head donelist;
132 unsigned long flags; /* see REQ_ bits below */
134 /* Maintain bio traversal state for part by part I/O submission.
135 * hard_* are block layer internals, no driver should touch them!
138 sector_t sector; /* next sector to submit */
139 unsigned long nr_sectors; /* no. of sectors left to submit */
140 /* no. of sectors left to submit in the current segment */
141 unsigned int current_nr_sectors;
143 sector_t hard_sector; /* next sector to complete */
144 unsigned long hard_nr_sectors; /* no. of sectors left to complete */
145 /* no. of sectors left to complete in the current segment */
146 unsigned int hard_cur_sectors;
151 void *elevator_private;
152 void *completion_data;
154 unsigned short ioprio;
156 int rq_status; /* should split this into a few status bits */
157 struct gendisk *rq_disk;
159 unsigned long start_time;
161 /* Number of scatter-gather DMA addr+len pairs after
162 * physical address coalescing is performed.
164 unsigned short nr_phys_segments;
166 /* Number of scatter-gather addr+len pairs after
167 * physical and DMA remapping hardware coalescing is performed.
168 * This is the number of scatter-gather entries the driver
169 * will actually have to deal with after DMA mapping is done.
171 unsigned short nr_hw_segments;
178 struct request_list *rl;
180 struct completion *waiting;
184 * when request is used as a packet command carrier
186 unsigned int cmd_len;
187 unsigned char cmd[BLK_MAX_CDB];
189 unsigned int data_len;
192 unsigned int sense_len;
195 unsigned int timeout;
199 * For Power Management requests
201 struct request_pm_state *pm;
204 * completion callback. end_io_data should be folded in with waiting
206 rq_end_io_fn *end_io;
211 * first three bits match BIO_RW* bits, important
214 __REQ_RW, /* not set, read. set, write */
215 __REQ_FAILFAST, /* no low level driver retries */
216 __REQ_SORTED, /* elevator knows about this request */
217 __REQ_SOFTBARRIER, /* may not be passed by ioscheduler */
218 __REQ_HARDBARRIER, /* may not be passed by drive either */
219 __REQ_FUA, /* forced unit access */
220 __REQ_CMD, /* is a regular fs rw request */
221 __REQ_NOMERGE, /* don't touch this for merging */
222 __REQ_STARTED, /* drive already may have started this one */
223 __REQ_DONTPREP, /* don't call prep for this one */
224 __REQ_QUEUED, /* uses queueing */
225 __REQ_ELVPRIV, /* elevator private data attached */
227 * for ATA/ATAPI devices
229 __REQ_PC, /* packet command (special) */
230 __REQ_BLOCK_PC, /* queued down pc from block layer */
231 __REQ_SENSE, /* sense retrival */
233 __REQ_FAILED, /* set if the request failed */
234 __REQ_QUIET, /* don't worry about errors */
235 __REQ_SPECIAL, /* driver suplied command */
238 __REQ_DRIVE_TASKFILE,
239 __REQ_PREEMPT, /* set for "ide_preempt" requests */
240 __REQ_PM_SUSPEND, /* suspend request */
241 __REQ_PM_RESUME, /* resume request */
242 __REQ_PM_SHUTDOWN, /* shutdown request */
243 __REQ_ORDERED_COLOR, /* is before or after barrier */
244 __REQ_RW_SYNC, /* request is sync (O_DIRECT) */
245 __REQ_NR_BITS, /* stops here */
248 #define REQ_RW (1 << __REQ_RW)
249 #define REQ_FAILFAST (1 << __REQ_FAILFAST)
250 #define REQ_SORTED (1 << __REQ_SORTED)
251 #define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER)
252 #define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER)
253 #define REQ_FUA (1 << __REQ_FUA)
254 #define REQ_CMD (1 << __REQ_CMD)
255 #define REQ_NOMERGE (1 << __REQ_NOMERGE)
256 #define REQ_STARTED (1 << __REQ_STARTED)
257 #define REQ_DONTPREP (1 << __REQ_DONTPREP)
258 #define REQ_QUEUED (1 << __REQ_QUEUED)
259 #define REQ_ELVPRIV (1 << __REQ_ELVPRIV)
260 #define REQ_PC (1 << __REQ_PC)
261 #define REQ_BLOCK_PC (1 << __REQ_BLOCK_PC)
262 #define REQ_SENSE (1 << __REQ_SENSE)
263 #define REQ_FAILED (1 << __REQ_FAILED)
264 #define REQ_QUIET (1 << __REQ_QUIET)
265 #define REQ_SPECIAL (1 << __REQ_SPECIAL)
266 #define REQ_DRIVE_CMD (1 << __REQ_DRIVE_CMD)
267 #define REQ_DRIVE_TASK (1 << __REQ_DRIVE_TASK)
268 #define REQ_DRIVE_TASKFILE (1 << __REQ_DRIVE_TASKFILE)
269 #define REQ_PREEMPT (1 << __REQ_PREEMPT)
270 #define REQ_PM_SUSPEND (1 << __REQ_PM_SUSPEND)
271 #define REQ_PM_RESUME (1 << __REQ_PM_RESUME)
272 #define REQ_PM_SHUTDOWN (1 << __REQ_PM_SHUTDOWN)
273 #define REQ_ORDERED_COLOR (1 << __REQ_ORDERED_COLOR)
274 #define REQ_RW_SYNC (1 << __REQ_RW_SYNC)
277 * State information carried for REQ_PM_SUSPEND and REQ_PM_RESUME
278 * requests. Some step values could eventually be made generic.
280 struct request_pm_state
282 /* PM state machine step value, currently driver specific */
284 /* requested PM state value (S1, S2, S3, S4, ...) */
286 void* data; /* for driver use */
289 #include <linux/elevator.h>
291 typedef int (merge_request_fn) (request_queue_t *, struct request *,
293 typedef int (merge_requests_fn) (request_queue_t *, struct request *,
295 typedef void (request_fn_proc) (request_queue_t *q);
296 typedef int (make_request_fn) (request_queue_t *q, struct bio *bio);
297 typedef int (prep_rq_fn) (request_queue_t *, struct request *);
298 typedef void (unplug_fn) (request_queue_t *);
301 typedef int (merge_bvec_fn) (request_queue_t *, struct bio *, struct bio_vec *);
302 typedef void (activity_fn) (void *data, int rw);
303 typedef int (issue_flush_fn) (request_queue_t *, struct gendisk *, sector_t *);
304 typedef void (prepare_flush_fn) (request_queue_t *, struct request *);
305 typedef void (softirq_done_fn)(struct request *);
307 enum blk_queue_state {
312 struct blk_queue_tag {
313 struct request **tag_index; /* map of busy tags */
314 unsigned long *tag_map; /* bit map of free/busy tags */
315 struct list_head busy_list; /* fifo list of busy tags */
316 int busy; /* current depth */
317 int max_depth; /* what we will send to device */
318 int real_max_depth; /* what the array can hold */
319 atomic_t refcnt; /* map can be shared */
325 * Together with queue_head for cacheline sharing
327 struct list_head queue_head;
328 struct request *last_merge;
329 elevator_t *elevator;
332 * the queue request freelist, one for reads and one for writes
334 struct request_list rq;
336 request_fn_proc *request_fn;
337 merge_request_fn *back_merge_fn;
338 merge_request_fn *front_merge_fn;
339 merge_requests_fn *merge_requests_fn;
340 make_request_fn *make_request_fn;
341 prep_rq_fn *prep_rq_fn;
342 unplug_fn *unplug_fn;
343 merge_bvec_fn *merge_bvec_fn;
344 activity_fn *activity_fn;
345 issue_flush_fn *issue_flush_fn;
346 prepare_flush_fn *prepare_flush_fn;
347 softirq_done_fn *softirq_done_fn;
350 * Dispatch queue sorting
353 struct request *boundary_rq;
356 * Auto-unplugging state
358 struct timer_list unplug_timer;
359 int unplug_thresh; /* After this many requests */
360 unsigned long unplug_delay; /* After this many jiffies */
361 struct work_struct unplug_work;
363 struct backing_dev_info backing_dev_info;
366 * The queue owner gets to use this for whatever they like.
367 * ll_rw_blk doesn't touch it.
374 * queue needs bounce pages for pages above this limit
376 unsigned long bounce_pfn;
380 * various queue flags, see QUEUE_* below
382 unsigned long queue_flags;
385 * protects queue structures from reentrancy. ->__queue_lock should
386 * _never_ be used directly, it is queue private. always use
389 spinlock_t __queue_lock;
390 spinlock_t *queue_lock;
400 unsigned long nr_requests; /* Max # of requests */
401 unsigned int nr_congestion_on;
402 unsigned int nr_congestion_off;
403 unsigned int nr_batching;
405 unsigned int max_sectors;
406 unsigned int max_hw_sectors;
407 unsigned short max_phys_segments;
408 unsigned short max_hw_segments;
409 unsigned short hardsect_size;
410 unsigned int max_segment_size;
412 unsigned long seg_boundary_mask;
413 unsigned int dma_alignment;
415 struct blk_queue_tag *queue_tags;
417 unsigned int nr_sorted;
418 unsigned int in_flight;
423 unsigned int sg_timeout;
424 unsigned int sg_reserved_size;
427 struct blk_trace *blk_trace;
430 * reserved for flush operations
432 unsigned int ordered, next_ordered, ordseq;
433 int orderr, ordcolor;
434 struct request pre_flush_rq, bar_rq, post_flush_rq;
435 struct request *orig_bar_rq;
436 unsigned int bi_size;
438 struct mutex sysfs_lock;
441 #define RQ_INACTIVE (-1)
444 #define QUEUE_FLAG_CLUSTER 0 /* cluster several segments into 1 */
445 #define QUEUE_FLAG_QUEUED 1 /* uses generic tag queueing */
446 #define QUEUE_FLAG_STOPPED 2 /* queue is stopped */
447 #define QUEUE_FLAG_READFULL 3 /* write queue has been filled */
448 #define QUEUE_FLAG_WRITEFULL 4 /* read queue has been filled */
449 #define QUEUE_FLAG_DEAD 5 /* queue being torn down */
450 #define QUEUE_FLAG_REENTER 6 /* Re-entrancy avoidance */
451 #define QUEUE_FLAG_PLUGGED 7 /* queue is plugged */
452 #define QUEUE_FLAG_ELVSWITCH 8 /* don't use elevator, just do FIFO */
456 * Hardbarrier is supported with one of the following methods.
458 * NONE : hardbarrier unsupported
459 * DRAIN : ordering by draining is enough
460 * DRAIN_FLUSH : ordering by draining w/ pre and post flushes
461 * DRAIN_FUA : ordering by draining w/ pre flush and FUA write
462 * TAG : ordering by tag is enough
463 * TAG_FLUSH : ordering by tag w/ pre and post flushes
464 * TAG_FUA : ordering by tag w/ pre flush and FUA write
466 QUEUE_ORDERED_NONE = 0x00,
467 QUEUE_ORDERED_DRAIN = 0x01,
468 QUEUE_ORDERED_TAG = 0x02,
470 QUEUE_ORDERED_PREFLUSH = 0x10,
471 QUEUE_ORDERED_POSTFLUSH = 0x20,
472 QUEUE_ORDERED_FUA = 0x40,
474 QUEUE_ORDERED_DRAIN_FLUSH = QUEUE_ORDERED_DRAIN |
475 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
476 QUEUE_ORDERED_DRAIN_FUA = QUEUE_ORDERED_DRAIN |
477 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
478 QUEUE_ORDERED_TAG_FLUSH = QUEUE_ORDERED_TAG |
479 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
480 QUEUE_ORDERED_TAG_FUA = QUEUE_ORDERED_TAG |
481 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
484 * Ordered operation sequence
486 QUEUE_ORDSEQ_STARTED = 0x01, /* flushing in progress */
487 QUEUE_ORDSEQ_DRAIN = 0x02, /* waiting for the queue to be drained */
488 QUEUE_ORDSEQ_PREFLUSH = 0x04, /* pre-flushing in progress */
489 QUEUE_ORDSEQ_BAR = 0x08, /* original barrier req in progress */
490 QUEUE_ORDSEQ_POSTFLUSH = 0x10, /* post-flushing in progress */
491 QUEUE_ORDSEQ_DONE = 0x20,
494 #define blk_queue_plugged(q) test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
495 #define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
496 #define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
497 #define blk_queue_flushing(q) ((q)->ordseq)
499 #define blk_fs_request(rq) ((rq)->flags & REQ_CMD)
500 #define blk_pc_request(rq) ((rq)->flags & REQ_BLOCK_PC)
501 #define blk_noretry_request(rq) ((rq)->flags & REQ_FAILFAST)
502 #define blk_rq_started(rq) ((rq)->flags & REQ_STARTED)
504 #define blk_account_rq(rq) (blk_rq_started(rq) && blk_fs_request(rq))
506 #define blk_pm_suspend_request(rq) ((rq)->flags & REQ_PM_SUSPEND)
507 #define blk_pm_resume_request(rq) ((rq)->flags & REQ_PM_RESUME)
508 #define blk_pm_request(rq) \
509 ((rq)->flags & (REQ_PM_SUSPEND | REQ_PM_RESUME))
511 #define blk_sorted_rq(rq) ((rq)->flags & REQ_SORTED)
512 #define blk_barrier_rq(rq) ((rq)->flags & REQ_HARDBARRIER)
513 #define blk_fua_rq(rq) ((rq)->flags & REQ_FUA)
515 #define list_entry_rq(ptr) list_entry((ptr), struct request, queuelist)
517 #define rq_data_dir(rq) ((rq)->flags & 1)
519 static inline int blk_queue_full(struct request_queue *q, int rw)
522 return test_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
523 return test_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
526 static inline void blk_set_queue_full(struct request_queue *q, int rw)
529 set_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
531 set_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
534 static inline void blk_clear_queue_full(struct request_queue *q, int rw)
537 clear_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
539 clear_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
544 * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
545 * it already be started by driver.
547 #define RQ_NOMERGE_FLAGS \
548 (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER)
549 #define rq_mergeable(rq) \
550 (!((rq)->flags & RQ_NOMERGE_FLAGS) && blk_fs_request((rq)))
553 * noop, requests are automagically marked as active/inactive by I/O
554 * scheduler -- see elv_next_request
556 #define blk_queue_headactive(q, head_active)
559 * q->prep_rq_fn return values
561 #define BLKPREP_OK 0 /* serve it */
562 #define BLKPREP_KILL 1 /* fatal error, kill */
563 #define BLKPREP_DEFER 2 /* leave on queue */
565 extern unsigned long blk_max_low_pfn, blk_max_pfn;
568 * standard bounce addresses:
570 * BLK_BOUNCE_HIGH : bounce all highmem pages
571 * BLK_BOUNCE_ANY : don't bounce anything
572 * BLK_BOUNCE_ISA : bounce pages above ISA DMA boundary
574 #define BLK_BOUNCE_HIGH ((u64)blk_max_low_pfn << PAGE_SHIFT)
575 #define BLK_BOUNCE_ANY ((u64)blk_max_pfn << PAGE_SHIFT)
576 #define BLK_BOUNCE_ISA (ISA_DMA_THRESHOLD)
579 extern int init_emergency_isa_pool(void);
580 extern void blk_queue_bounce(request_queue_t *q, struct bio **bio);
582 static inline int init_emergency_isa_pool(void)
586 static inline void blk_queue_bounce(request_queue_t *q, struct bio **bio)
589 #endif /* CONFIG_MMU */
591 #define rq_for_each_bio(_bio, rq) \
593 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
597 unsigned block_size_bits;
600 extern int blk_register_queue(struct gendisk *disk);
601 extern void blk_unregister_queue(struct gendisk *disk);
602 extern void register_disk(struct gendisk *dev);
603 extern void generic_make_request(struct bio *bio);
604 extern void blk_put_request(struct request *);
605 extern void __blk_put_request(request_queue_t *, struct request *);
606 extern void blk_end_sync_rq(struct request *rq, int error);
607 extern struct request *blk_get_request(request_queue_t *, int, gfp_t);
608 extern void blk_insert_request(request_queue_t *, struct request *, int, void *);
609 extern void blk_requeue_request(request_queue_t *, struct request *);
610 extern void blk_plug_device(request_queue_t *);
611 extern int blk_remove_plug(request_queue_t *);
612 extern void blk_recount_segments(request_queue_t *, struct bio *);
613 extern int scsi_cmd_ioctl(struct file *, struct gendisk *, unsigned int, void __user *);
614 extern int sg_scsi_ioctl(struct file *, struct request_queue *,
615 struct gendisk *, struct scsi_ioctl_command __user *);
616 extern void blk_start_queue(request_queue_t *q);
617 extern void blk_stop_queue(request_queue_t *q);
618 extern void blk_sync_queue(struct request_queue *q);
619 extern void __blk_stop_queue(request_queue_t *q);
620 extern void blk_run_queue(request_queue_t *);
621 extern void blk_queue_activity_fn(request_queue_t *, activity_fn *, void *);
622 extern int blk_rq_map_user(request_queue_t *, struct request *, void __user *, unsigned int);
623 extern int blk_rq_unmap_user(struct bio *, unsigned int);
624 extern int blk_rq_map_kern(request_queue_t *, struct request *, void *, unsigned int, gfp_t);
625 extern int blk_rq_map_user_iov(request_queue_t *, struct request *, struct sg_iovec *, int);
626 extern int blk_execute_rq(request_queue_t *, struct gendisk *,
627 struct request *, int);
628 extern void blk_execute_rq_nowait(request_queue_t *, struct gendisk *,
629 struct request *, int, rq_end_io_fn *);
631 static inline request_queue_t *bdev_get_queue(struct block_device *bdev)
633 return bdev->bd_disk->queue;
636 static inline void blk_run_backing_dev(struct backing_dev_info *bdi,
639 if (bdi && bdi->unplug_io_fn)
640 bdi->unplug_io_fn(bdi, page);
643 static inline void blk_run_address_space(struct address_space *mapping)
646 blk_run_backing_dev(mapping->backing_dev_info, NULL);
650 * end_request() and friends. Must be called with the request queue spinlock
651 * acquired. All functions called within end_request() _must_be_ atomic.
653 * Several drivers define their own end_request and call
654 * end_that_request_first() and end_that_request_last()
655 * for parts of the original function. This prevents
656 * code duplication in drivers.
658 extern int end_that_request_first(struct request *, int, int);
659 extern int end_that_request_chunk(struct request *, int, int);
660 extern void end_that_request_last(struct request *, int);
661 extern void end_request(struct request *req, int uptodate);
662 extern void blk_complete_request(struct request *);
664 static inline int rq_all_done(struct request *rq, unsigned int nr_bytes)
666 if (blk_fs_request(rq))
667 return (nr_bytes >= (rq->hard_nr_sectors << 9));
668 else if (blk_pc_request(rq))
669 return nr_bytes >= rq->data_len;
675 * end_that_request_first/chunk() takes an uptodate argument. we account
676 * any value <= as an io error. 0 means -EIO for compatability reasons,
677 * any other < 0 value is the direct error type. An uptodate value of
678 * 1 indicates successful io completion
680 #define end_io_error(uptodate) (unlikely((uptodate) <= 0))
682 static inline void blkdev_dequeue_request(struct request *req)
684 elv_dequeue_request(req->q, req);
688 * This should be in elevator.h, but that requires pulling in rq and q
690 static inline void elv_dispatch_add_tail(struct request_queue *q,
693 if (q->last_merge == rq)
694 q->last_merge = NULL;
697 q->end_sector = rq_end_sector(rq);
699 list_add_tail(&rq->queuelist, &q->queue_head);
703 * Access functions for manipulating queue properties
705 extern request_queue_t *blk_init_queue_node(request_fn_proc *rfn,
706 spinlock_t *lock, int node_id);
707 extern request_queue_t *blk_init_queue(request_fn_proc *, spinlock_t *);
708 extern void blk_cleanup_queue(request_queue_t *);
709 extern void blk_queue_make_request(request_queue_t *, make_request_fn *);
710 extern void blk_queue_bounce_limit(request_queue_t *, u64);
711 extern void blk_queue_max_sectors(request_queue_t *, unsigned int);
712 extern void blk_queue_max_phys_segments(request_queue_t *, unsigned short);
713 extern void blk_queue_max_hw_segments(request_queue_t *, unsigned short);
714 extern void blk_queue_max_segment_size(request_queue_t *, unsigned int);
715 extern void blk_queue_hardsect_size(request_queue_t *, unsigned short);
716 extern void blk_queue_stack_limits(request_queue_t *t, request_queue_t *b);
717 extern void blk_queue_segment_boundary(request_queue_t *, unsigned long);
718 extern void blk_queue_prep_rq(request_queue_t *, prep_rq_fn *pfn);
719 extern void blk_queue_merge_bvec(request_queue_t *, merge_bvec_fn *);
720 extern void blk_queue_dma_alignment(request_queue_t *, int);
721 extern void blk_queue_softirq_done(request_queue_t *, softirq_done_fn *);
722 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
723 extern int blk_queue_ordered(request_queue_t *, unsigned, prepare_flush_fn *);
724 extern void blk_queue_issue_flush_fn(request_queue_t *, issue_flush_fn *);
725 extern int blk_do_ordered(request_queue_t *, struct request **);
726 extern unsigned blk_ordered_cur_seq(request_queue_t *);
727 extern unsigned blk_ordered_req_seq(struct request *);
728 extern void blk_ordered_complete_seq(request_queue_t *, unsigned, int);
730 extern int blk_rq_map_sg(request_queue_t *, struct request *, struct scatterlist *);
731 extern void blk_dump_rq_flags(struct request *, char *);
732 extern void generic_unplug_device(request_queue_t *);
733 extern void __generic_unplug_device(request_queue_t *);
734 extern long nr_blockdev_pages(void);
736 int blk_get_queue(request_queue_t *);
737 request_queue_t *blk_alloc_queue(gfp_t);
738 request_queue_t *blk_alloc_queue_node(gfp_t, int);
739 extern void blk_put_queue(request_queue_t *);
744 #define blk_queue_tag_depth(q) ((q)->queue_tags->busy)
745 #define blk_queue_tag_queue(q) ((q)->queue_tags->busy < (q)->queue_tags->max_depth)
746 #define blk_rq_tagged(rq) ((rq)->flags & REQ_QUEUED)
747 extern int blk_queue_start_tag(request_queue_t *, struct request *);
748 extern struct request *blk_queue_find_tag(request_queue_t *, int);
749 extern void blk_queue_end_tag(request_queue_t *, struct request *);
750 extern int blk_queue_init_tags(request_queue_t *, int, struct blk_queue_tag *);
751 extern void blk_queue_free_tags(request_queue_t *);
752 extern int blk_queue_resize_tags(request_queue_t *, int);
753 extern void blk_queue_invalidate_tags(request_queue_t *);
754 extern long blk_congestion_wait(int rw, long timeout);
756 extern void blk_rq_bio_prep(request_queue_t *, struct request *, struct bio *);
757 extern int blkdev_issue_flush(struct block_device *, sector_t *);
759 #define MAX_PHYS_SEGMENTS 128
760 #define MAX_HW_SEGMENTS 128
761 #define SAFE_MAX_SECTORS 255
762 #define BLK_DEF_MAX_SECTORS 1024
764 #define MAX_SEGMENT_SIZE 65536
766 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
768 static inline int queue_hardsect_size(request_queue_t *q)
772 if (q && q->hardsect_size)
773 retval = q->hardsect_size;
778 static inline int bdev_hardsect_size(struct block_device *bdev)
780 return queue_hardsect_size(bdev_get_queue(bdev));
783 static inline int queue_dma_alignment(request_queue_t *q)
787 if (q && q->dma_alignment)
788 retval = q->dma_alignment;
793 static inline int bdev_dma_aligment(struct block_device *bdev)
795 return queue_dma_alignment(bdev_get_queue(bdev));
798 #define blk_finished_io(nsects) do { } while (0)
799 #define blk_started_io(nsects) do { } while (0)
801 /* assumes size > 256 */
802 static inline unsigned int blksize_bits(unsigned int size)
804 unsigned int bits = 8;
808 } while (size > 256);
812 static inline unsigned int block_size(struct block_device *bdev)
814 return bdev->bd_block_size;
817 typedef struct {struct page *v;} Sector;
819 unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
821 static inline void put_dev_sector(Sector p)
823 page_cache_release(p.v);
827 int kblockd_schedule_work(struct work_struct *work);
828 void kblockd_flush(void);
831 # include <asm/div64.h>
832 # define sector_div(a, b) do_div(a, b)
834 # define sector_div(n, b)( \
844 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
845 MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
846 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
847 MODULE_ALIAS("block-major-" __stringify(major) "-*")