blob: 70ac2860a605342199b4d68c2215154eb2921645 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001#ifndef _LINUX_BLKDEV_H
2#define _LINUX_BLKDEV_H
3
4#include <linux/config.h>
5#include <linux/major.h>
6#include <linux/genhd.h>
7#include <linux/list.h>
8#include <linux/timer.h>
9#include <linux/workqueue.h>
10#include <linux/pagemap.h>
11#include <linux/backing-dev.h>
12#include <linux/wait.h>
13#include <linux/mempool.h>
14#include <linux/bio.h>
15#include <linux/module.h>
16#include <linux/stringify.h>
17
18#include <asm/scatterlist.h>
19
20struct request_queue;
21typedef struct request_queue request_queue_t;
22struct elevator_queue;
23typedef struct elevator_queue elevator_t;
24struct request_pm_state;
25
26#define BLKDEV_MIN_RQ 4
27#define BLKDEV_MAX_RQ 128 /* Default maximum */
28
29/*
30 * This is the per-process anticipatory I/O scheduler state.
31 */
32struct as_io_context {
33 spinlock_t lock;
34
35 void (*dtor)(struct as_io_context *aic); /* destructor */
36 void (*exit)(struct as_io_context *aic); /* called on task exit */
37
38 unsigned long state;
39 atomic_t nr_queued; /* queued reads & sync writes */
40 atomic_t nr_dispatched; /* number of requests gone to the drivers */
41
42 /* IO History tracking */
43 /* Thinktime */
44 unsigned long last_end_request;
45 unsigned long ttime_total;
46 unsigned long ttime_samples;
47 unsigned long ttime_mean;
48 /* Layout pattern */
49 unsigned int seek_samples;
50 sector_t last_request_pos;
51 u64 seek_total;
52 sector_t seek_mean;
53};
54
55struct cfq_queue;
56struct cfq_io_context {
57 void (*dtor)(struct cfq_io_context *);
58 void (*exit)(struct cfq_io_context *);
59
60 struct io_context *ioc;
61
62 /*
63 * circular list of cfq_io_contexts belonging to a process io context
64 */
65 struct list_head list;
66 struct cfq_queue *cfqq;
67};
68
69/*
70 * This is the per-process I/O subsystem state. It is refcounted and
71 * kmalloc'ed. Currently all fields are modified in process io context
72 * (apart from the atomic refcount), so require no locking.
73 */
74struct io_context {
75 atomic_t refcount;
76 pid_t pid;
77
78 /*
79 * For request batching
80 */
81 unsigned long last_waited; /* Time last woken after wait for request */
82 int nr_batch_requests; /* Number of requests left in the batch */
83
84 spinlock_t lock;
85
86 struct as_io_context *aic;
87 struct cfq_io_context *cic;
88};
89
90void put_io_context(struct io_context *ioc);
91void exit_io_context(void);
92struct io_context *get_io_context(int gfp_flags);
93void copy_io_context(struct io_context **pdst, struct io_context **psrc);
94void swap_io_context(struct io_context **ioc1, struct io_context **ioc2);
95
96struct request;
97typedef void (rq_end_io_fn)(struct request *);
98
99struct request_list {
100 int count[2];
101 int starved[2];
102 mempool_t *rq_pool;
103 wait_queue_head_t wait[2];
104 wait_queue_head_t drain;
105};
106
107#define BLK_MAX_CDB 16
108
109/*
110 * try to put the fields that are referenced together in the same cacheline
111 */
112struct request {
113 struct list_head queuelist; /* looking for ->queue? you must _not_
114 * access it directly, use
115 * blkdev_dequeue_request! */
116 unsigned long flags; /* see REQ_ bits below */
117
118 /* Maintain bio traversal state for part by part I/O submission.
119 * hard_* are block layer internals, no driver should touch them!
120 */
121
122 sector_t sector; /* next sector to submit */
123 unsigned long nr_sectors; /* no. of sectors left to submit */
124 /* no. of sectors left to submit in the current segment */
125 unsigned int current_nr_sectors;
126
127 sector_t hard_sector; /* next sector to complete */
128 unsigned long hard_nr_sectors; /* no. of sectors left to complete */
129 /* no. of sectors left to complete in the current segment */
130 unsigned int hard_cur_sectors;
131
132 struct bio *bio;
133 struct bio *biotail;
134
135 void *elevator_private;
136
137 int rq_status; /* should split this into a few status bits */
138 struct gendisk *rq_disk;
139 int errors;
140 unsigned long start_time;
141
142 /* Number of scatter-gather DMA addr+len pairs after
143 * physical address coalescing is performed.
144 */
145 unsigned short nr_phys_segments;
146
147 /* Number of scatter-gather addr+len pairs after
148 * physical and DMA remapping hardware coalescing is performed.
149 * This is the number of scatter-gather entries the driver
150 * will actually have to deal with after DMA mapping is done.
151 */
152 unsigned short nr_hw_segments;
153
154 int tag;
155 char *buffer;
156
157 int ref_count;
158 request_queue_t *q;
159 struct request_list *rl;
160
161 struct completion *waiting;
162 void *special;
163
164 /*
165 * when request is used as a packet command carrier
166 */
167 unsigned int cmd_len;
168 unsigned char cmd[BLK_MAX_CDB];
169
170 unsigned int data_len;
171 void *data;
172
173 unsigned int sense_len;
174 void *sense;
175
176 unsigned int timeout;
177
178 /*
179 * For Power Management requests
180 */
181 struct request_pm_state *pm;
182
183 /*
184 * completion callback. end_io_data should be folded in with waiting
185 */
186 rq_end_io_fn *end_io;
187 void *end_io_data;
188};
189
190/*
191 * first three bits match BIO_RW* bits, important
192 */
193enum rq_flag_bits {
194 __REQ_RW, /* not set, read. set, write */
195 __REQ_FAILFAST, /* no low level driver retries */
196 __REQ_SOFTBARRIER, /* may not be passed by ioscheduler */
197 __REQ_HARDBARRIER, /* may not be passed by drive either */
198 __REQ_CMD, /* is a regular fs rw request */
199 __REQ_NOMERGE, /* don't touch this for merging */
200 __REQ_STARTED, /* drive already may have started this one */
201 __REQ_DONTPREP, /* don't call prep for this one */
202 __REQ_QUEUED, /* uses queueing */
203 /*
204 * for ATA/ATAPI devices
205 */
206 __REQ_PC, /* packet command (special) */
207 __REQ_BLOCK_PC, /* queued down pc from block layer */
208 __REQ_SENSE, /* sense retrival */
209
210 __REQ_FAILED, /* set if the request failed */
211 __REQ_QUIET, /* don't worry about errors */
212 __REQ_SPECIAL, /* driver suplied command */
213 __REQ_DRIVE_CMD,
214 __REQ_DRIVE_TASK,
215 __REQ_DRIVE_TASKFILE,
216 __REQ_PREEMPT, /* set for "ide_preempt" requests */
217 __REQ_PM_SUSPEND, /* suspend request */
218 __REQ_PM_RESUME, /* resume request */
219 __REQ_PM_SHUTDOWN, /* shutdown request */
220 __REQ_BAR_PREFLUSH, /* barrier pre-flush done */
221 __REQ_BAR_POSTFLUSH, /* barrier post-flush */
222 __REQ_BAR_FLUSH, /* rq is the flush request */
223 __REQ_NR_BITS, /* stops here */
224};
225
226#define REQ_RW (1 << __REQ_RW)
227#define REQ_FAILFAST (1 << __REQ_FAILFAST)
228#define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER)
229#define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER)
230#define REQ_CMD (1 << __REQ_CMD)
231#define REQ_NOMERGE (1 << __REQ_NOMERGE)
232#define REQ_STARTED (1 << __REQ_STARTED)
233#define REQ_DONTPREP (1 << __REQ_DONTPREP)
234#define REQ_QUEUED (1 << __REQ_QUEUED)
235#define REQ_PC (1 << __REQ_PC)
236#define REQ_BLOCK_PC (1 << __REQ_BLOCK_PC)
237#define REQ_SENSE (1 << __REQ_SENSE)
238#define REQ_FAILED (1 << __REQ_FAILED)
239#define REQ_QUIET (1 << __REQ_QUIET)
240#define REQ_SPECIAL (1 << __REQ_SPECIAL)
241#define REQ_DRIVE_CMD (1 << __REQ_DRIVE_CMD)
242#define REQ_DRIVE_TASK (1 << __REQ_DRIVE_TASK)
243#define REQ_DRIVE_TASKFILE (1 << __REQ_DRIVE_TASKFILE)
244#define REQ_PREEMPT (1 << __REQ_PREEMPT)
245#define REQ_PM_SUSPEND (1 << __REQ_PM_SUSPEND)
246#define REQ_PM_RESUME (1 << __REQ_PM_RESUME)
247#define REQ_PM_SHUTDOWN (1 << __REQ_PM_SHUTDOWN)
248#define REQ_BAR_PREFLUSH (1 << __REQ_BAR_PREFLUSH)
249#define REQ_BAR_POSTFLUSH (1 << __REQ_BAR_POSTFLUSH)
250#define REQ_BAR_FLUSH (1 << __REQ_BAR_FLUSH)
251
252/*
253 * State information carried for REQ_PM_SUSPEND and REQ_PM_RESUME
254 * requests. Some step values could eventually be made generic.
255 */
256struct request_pm_state
257{
258 /* PM state machine step value, currently driver specific */
259 int pm_step;
260 /* requested PM state value (S1, S2, S3, S4, ...) */
261 u32 pm_state;
262 void* data; /* for driver use */
263};
264
265#include <linux/elevator.h>
266
267typedef int (merge_request_fn) (request_queue_t *, struct request *,
268 struct bio *);
269typedef int (merge_requests_fn) (request_queue_t *, struct request *,
270 struct request *);
271typedef void (request_fn_proc) (request_queue_t *q);
272typedef int (make_request_fn) (request_queue_t *q, struct bio *bio);
273typedef int (prep_rq_fn) (request_queue_t *, struct request *);
274typedef void (unplug_fn) (request_queue_t *);
275
276struct bio_vec;
277typedef int (merge_bvec_fn) (request_queue_t *, struct bio *, struct bio_vec *);
278typedef void (activity_fn) (void *data, int rw);
279typedef int (issue_flush_fn) (request_queue_t *, struct gendisk *, sector_t *);
280typedef int (prepare_flush_fn) (request_queue_t *, struct request *);
281typedef void (end_flush_fn) (request_queue_t *, struct request *);
282
283enum blk_queue_state {
284 Queue_down,
285 Queue_up,
286};
287
288#define BLK_TAGS_PER_LONG (sizeof(unsigned long) * 8)
289#define BLK_TAGS_MASK (BLK_TAGS_PER_LONG - 1)
290
291struct blk_queue_tag {
292 struct request **tag_index; /* map of busy tags */
293 unsigned long *tag_map; /* bit map of free/busy tags */
294 struct list_head busy_list; /* fifo list of busy tags */
295 int busy; /* current depth */
296 int max_depth; /* what we will send to device */
297 int real_max_depth; /* what the array can hold */
298 atomic_t refcnt; /* map can be shared */
299};
300
301struct request_queue
302{
303 /*
304 * Together with queue_head for cacheline sharing
305 */
306 struct list_head queue_head;
307 struct request *last_merge;
308 elevator_t *elevator;
309
310 /*
311 * the queue request freelist, one for reads and one for writes
312 */
313 struct request_list rq;
314
315 request_fn_proc *request_fn;
316 merge_request_fn *back_merge_fn;
317 merge_request_fn *front_merge_fn;
318 merge_requests_fn *merge_requests_fn;
319 make_request_fn *make_request_fn;
320 prep_rq_fn *prep_rq_fn;
321 unplug_fn *unplug_fn;
322 merge_bvec_fn *merge_bvec_fn;
323 activity_fn *activity_fn;
324 issue_flush_fn *issue_flush_fn;
325 prepare_flush_fn *prepare_flush_fn;
326 end_flush_fn *end_flush_fn;
327
328 /*
329 * Auto-unplugging state
330 */
331 struct timer_list unplug_timer;
332 int unplug_thresh; /* After this many requests */
333 unsigned long unplug_delay; /* After this many jiffies */
334 struct work_struct unplug_work;
335
336 struct backing_dev_info backing_dev_info;
337
338 /*
339 * The queue owner gets to use this for whatever they like.
340 * ll_rw_blk doesn't touch it.
341 */
342 void *queuedata;
343
344 void *activity_data;
345
346 /*
347 * queue needs bounce pages for pages above this limit
348 */
349 unsigned long bounce_pfn;
350 unsigned int bounce_gfp;
351
352 /*
353 * various queue flags, see QUEUE_* below
354 */
355 unsigned long queue_flags;
356
357 /*
358 * protects queue structures from reentrancy
359 */
360 spinlock_t *queue_lock;
361
362 /*
363 * queue kobject
364 */
365 struct kobject kobj;
366
367 /*
368 * queue settings
369 */
370 unsigned long nr_requests; /* Max # of requests */
371 unsigned int nr_congestion_on;
372 unsigned int nr_congestion_off;
373 unsigned int nr_batching;
374
375 unsigned short max_sectors;
376 unsigned short max_hw_sectors;
377 unsigned short max_phys_segments;
378 unsigned short max_hw_segments;
379 unsigned short hardsect_size;
380 unsigned int max_segment_size;
381
382 unsigned long seg_boundary_mask;
383 unsigned int dma_alignment;
384
385 struct blk_queue_tag *queue_tags;
386
387 atomic_t refcnt;
388
389 unsigned int in_flight;
390
391 /*
392 * sg stuff
393 */
394 unsigned int sg_timeout;
395 unsigned int sg_reserved_size;
396
397 struct list_head drain_list;
398
399 /*
400 * reserved for flush operations
401 */
402 struct request *flush_rq;
403 unsigned char ordered;
404};
405
406enum {
407 QUEUE_ORDERED_NONE,
408 QUEUE_ORDERED_TAG,
409 QUEUE_ORDERED_FLUSH,
410};
411
412#define RQ_INACTIVE (-1)
413#define RQ_ACTIVE 1
414#define RQ_SCSI_BUSY 0xffff
415#define RQ_SCSI_DONE 0xfffe
416#define RQ_SCSI_DISCONNECTING 0xffe0
417
418#define QUEUE_FLAG_CLUSTER 0 /* cluster several segments into 1 */
419#define QUEUE_FLAG_QUEUED 1 /* uses generic tag queueing */
420#define QUEUE_FLAG_STOPPED 2 /* queue is stopped */
421#define QUEUE_FLAG_READFULL 3 /* write queue has been filled */
422#define QUEUE_FLAG_WRITEFULL 4 /* read queue has been filled */
423#define QUEUE_FLAG_DEAD 5 /* queue being torn down */
424#define QUEUE_FLAG_REENTER 6 /* Re-entrancy avoidance */
425#define QUEUE_FLAG_PLUGGED 7 /* queue is plugged */
426#define QUEUE_FLAG_DRAIN 8 /* draining queue for sched switch */
427#define QUEUE_FLAG_FLUSH 9 /* doing barrier flush sequence */
428
429#define blk_queue_plugged(q) test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
430#define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
431#define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
432#define blk_queue_flushing(q) test_bit(QUEUE_FLAG_FLUSH, &(q)->queue_flags)
433
434#define blk_fs_request(rq) ((rq)->flags & REQ_CMD)
435#define blk_pc_request(rq) ((rq)->flags & REQ_BLOCK_PC)
436#define blk_noretry_request(rq) ((rq)->flags & REQ_FAILFAST)
437#define blk_rq_started(rq) ((rq)->flags & REQ_STARTED)
438
439#define blk_account_rq(rq) (blk_rq_started(rq) && blk_fs_request(rq))
440
441#define blk_pm_suspend_request(rq) ((rq)->flags & REQ_PM_SUSPEND)
442#define blk_pm_resume_request(rq) ((rq)->flags & REQ_PM_RESUME)
443#define blk_pm_request(rq) \
444 ((rq)->flags & (REQ_PM_SUSPEND | REQ_PM_RESUME))
445
446#define blk_barrier_rq(rq) ((rq)->flags & REQ_HARDBARRIER)
447#define blk_barrier_preflush(rq) ((rq)->flags & REQ_BAR_PREFLUSH)
448#define blk_barrier_postflush(rq) ((rq)->flags & REQ_BAR_POSTFLUSH)
449
450#define list_entry_rq(ptr) list_entry((ptr), struct request, queuelist)
451
452#define rq_data_dir(rq) ((rq)->flags & 1)
453
454static inline int blk_queue_full(struct request_queue *q, int rw)
455{
456 if (rw == READ)
457 return test_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
458 return test_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
459}
460
461static inline void blk_set_queue_full(struct request_queue *q, int rw)
462{
463 if (rw == READ)
464 set_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
465 else
466 set_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
467}
468
469static inline void blk_clear_queue_full(struct request_queue *q, int rw)
470{
471 if (rw == READ)
472 clear_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
473 else
474 clear_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
475}
476
477
478/*
479 * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
480 * it already be started by driver.
481 */
482#define RQ_NOMERGE_FLAGS \
483 (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER)
484#define rq_mergeable(rq) \
485 (!((rq)->flags & RQ_NOMERGE_FLAGS) && blk_fs_request((rq)))
486
487/*
488 * noop, requests are automagically marked as active/inactive by I/O
489 * scheduler -- see elv_next_request
490 */
491#define blk_queue_headactive(q, head_active)
492
493/*
494 * q->prep_rq_fn return values
495 */
496#define BLKPREP_OK 0 /* serve it */
497#define BLKPREP_KILL 1 /* fatal error, kill */
498#define BLKPREP_DEFER 2 /* leave on queue */
499
500extern unsigned long blk_max_low_pfn, blk_max_pfn;
501
502/*
503 * standard bounce addresses:
504 *
505 * BLK_BOUNCE_HIGH : bounce all highmem pages
506 * BLK_BOUNCE_ANY : don't bounce anything
507 * BLK_BOUNCE_ISA : bounce pages above ISA DMA boundary
508 */
509#define BLK_BOUNCE_HIGH ((u64)blk_max_low_pfn << PAGE_SHIFT)
510#define BLK_BOUNCE_ANY ((u64)blk_max_pfn << PAGE_SHIFT)
511#define BLK_BOUNCE_ISA (ISA_DMA_THRESHOLD)
512
513#ifdef CONFIG_MMU
514extern int init_emergency_isa_pool(void);
515extern void blk_queue_bounce(request_queue_t *q, struct bio **bio);
516#else
517static inline int init_emergency_isa_pool(void)
518{
519 return 0;
520}
521static inline void blk_queue_bounce(request_queue_t *q, struct bio **bio)
522{
523}
524#endif /* CONFIG_MMU */
525
526#define rq_for_each_bio(_bio, rq) \
527 if ((rq->bio)) \
528 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
529
530struct sec_size {
531 unsigned block_size;
532 unsigned block_size_bits;
533};
534
535extern int blk_register_queue(struct gendisk *disk);
536extern void blk_unregister_queue(struct gendisk *disk);
537extern void register_disk(struct gendisk *dev);
538extern void generic_make_request(struct bio *bio);
539extern void blk_put_request(struct request *);
540extern void blk_end_sync_rq(struct request *rq);
541extern void blk_attempt_remerge(request_queue_t *, struct request *);
542extern void __blk_attempt_remerge(request_queue_t *, struct request *);
543extern struct request *blk_get_request(request_queue_t *, int, int);
544extern void blk_insert_request(request_queue_t *, struct request *, int, void *, int);
545extern void blk_requeue_request(request_queue_t *, struct request *);
546extern void blk_plug_device(request_queue_t *);
547extern int blk_remove_plug(request_queue_t *);
548extern void blk_recount_segments(request_queue_t *, struct bio *);
549extern int blk_phys_contig_segment(request_queue_t *q, struct bio *, struct bio *);
550extern int blk_hw_contig_segment(request_queue_t *q, struct bio *, struct bio *);
551extern int scsi_cmd_ioctl(struct file *, struct gendisk *, unsigned int, void __user *);
552extern void blk_start_queue(request_queue_t *q);
553extern void blk_stop_queue(request_queue_t *q);
554extern void blk_sync_queue(struct request_queue *q);
555extern void __blk_stop_queue(request_queue_t *q);
556extern void blk_run_queue(request_queue_t *);
557extern void blk_queue_activity_fn(request_queue_t *, activity_fn *, void *);
558extern struct request *blk_rq_map_user(request_queue_t *, int, void __user *, unsigned int);
559extern int blk_rq_unmap_user(struct request *, struct bio *, unsigned int);
560extern int blk_execute_rq(request_queue_t *, struct gendisk *, struct request *);
561
562static inline request_queue_t *bdev_get_queue(struct block_device *bdev)
563{
564 return bdev->bd_disk->queue;
565}
566
567static inline void blk_run_backing_dev(struct backing_dev_info *bdi,
568 struct page *page)
569{
570 if (bdi && bdi->unplug_io_fn)
571 bdi->unplug_io_fn(bdi, page);
572}
573
574static inline void blk_run_address_space(struct address_space *mapping)
575{
576 if (mapping)
577 blk_run_backing_dev(mapping->backing_dev_info, NULL);
578}
579
580/*
581 * end_request() and friends. Must be called with the request queue spinlock
582 * acquired. All functions called within end_request() _must_be_ atomic.
583 *
584 * Several drivers define their own end_request and call
585 * end_that_request_first() and end_that_request_last()
586 * for parts of the original function. This prevents
587 * code duplication in drivers.
588 */
589extern int end_that_request_first(struct request *, int, int);
590extern int end_that_request_chunk(struct request *, int, int);
591extern void end_that_request_last(struct request *);
592extern void end_request(struct request *req, int uptodate);
593
594/*
595 * end_that_request_first/chunk() takes an uptodate argument. we account
596 * any value <= as an io error. 0 means -EIO for compatability reasons,
597 * any other < 0 value is the direct error type. An uptodate value of
598 * 1 indicates successful io completion
599 */
600#define end_io_error(uptodate) (unlikely((uptodate) <= 0))
601
602static inline void blkdev_dequeue_request(struct request *req)
603{
604 BUG_ON(list_empty(&req->queuelist));
605
606 list_del_init(&req->queuelist);
607
608 if (req->rl)
609 elv_remove_request(req->q, req);
610}
611
612/*
613 * Access functions for manipulating queue properties
614 */
615extern request_queue_t *blk_init_queue(request_fn_proc *, spinlock_t *);
616extern void blk_cleanup_queue(request_queue_t *);
617extern void blk_queue_make_request(request_queue_t *, make_request_fn *);
618extern void blk_queue_bounce_limit(request_queue_t *, u64);
619extern void blk_queue_max_sectors(request_queue_t *, unsigned short);
620extern void blk_queue_max_phys_segments(request_queue_t *, unsigned short);
621extern void blk_queue_max_hw_segments(request_queue_t *, unsigned short);
622extern void blk_queue_max_segment_size(request_queue_t *, unsigned int);
623extern void blk_queue_hardsect_size(request_queue_t *, unsigned short);
624extern void blk_queue_stack_limits(request_queue_t *t, request_queue_t *b);
625extern void blk_queue_segment_boundary(request_queue_t *, unsigned long);
626extern void blk_queue_prep_rq(request_queue_t *, prep_rq_fn *pfn);
627extern void blk_queue_merge_bvec(request_queue_t *, merge_bvec_fn *);
628extern void blk_queue_dma_alignment(request_queue_t *, int);
629extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
630extern void blk_queue_ordered(request_queue_t *, int);
631extern void blk_queue_issue_flush_fn(request_queue_t *, issue_flush_fn *);
632extern int blkdev_scsi_issue_flush_fn(request_queue_t *, struct gendisk *, sector_t *);
633extern struct request *blk_start_pre_flush(request_queue_t *,struct request *);
634extern int blk_complete_barrier_rq(request_queue_t *, struct request *, int);
635extern int blk_complete_barrier_rq_locked(request_queue_t *, struct request *, int);
636
637extern int blk_rq_map_sg(request_queue_t *, struct request *, struct scatterlist *);
638extern void blk_dump_rq_flags(struct request *, char *);
639extern void generic_unplug_device(request_queue_t *);
640extern void __generic_unplug_device(request_queue_t *);
641extern long nr_blockdev_pages(void);
642extern void blk_wait_queue_drained(request_queue_t *, int);
643extern void blk_finish_queue_drain(request_queue_t *);
644
645int blk_get_queue(request_queue_t *);
646request_queue_t *blk_alloc_queue(int);
647#define blk_put_queue(q) blk_cleanup_queue((q))
648
649/*
650 * tag stuff
651 */
652#define blk_queue_tag_depth(q) ((q)->queue_tags->busy)
653#define blk_queue_tag_queue(q) ((q)->queue_tags->busy < (q)->queue_tags->max_depth)
654#define blk_rq_tagged(rq) ((rq)->flags & REQ_QUEUED)
655extern int blk_queue_start_tag(request_queue_t *, struct request *);
656extern struct request *blk_queue_find_tag(request_queue_t *, int);
657extern void blk_queue_end_tag(request_queue_t *, struct request *);
658extern int blk_queue_init_tags(request_queue_t *, int, struct blk_queue_tag *);
659extern void blk_queue_free_tags(request_queue_t *);
660extern int blk_queue_resize_tags(request_queue_t *, int);
661extern void blk_queue_invalidate_tags(request_queue_t *);
662extern long blk_congestion_wait(int rw, long timeout);
663
664extern void blk_rq_bio_prep(request_queue_t *, struct request *, struct bio *);
665extern int blkdev_issue_flush(struct block_device *, sector_t *);
666
667#define MAX_PHYS_SEGMENTS 128
668#define MAX_HW_SEGMENTS 128
669#define MAX_SECTORS 255
670
671#define MAX_SEGMENT_SIZE 65536
672
673#define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
674
675extern void drive_stat_acct(struct request *, int, int);
676
677static inline int queue_hardsect_size(request_queue_t *q)
678{
679 int retval = 512;
680
681 if (q && q->hardsect_size)
682 retval = q->hardsect_size;
683
684 return retval;
685}
686
687static inline int bdev_hardsect_size(struct block_device *bdev)
688{
689 return queue_hardsect_size(bdev_get_queue(bdev));
690}
691
692static inline int queue_dma_alignment(request_queue_t *q)
693{
694 int retval = 511;
695
696 if (q && q->dma_alignment)
697 retval = q->dma_alignment;
698
699 return retval;
700}
701
702static inline int bdev_dma_aligment(struct block_device *bdev)
703{
704 return queue_dma_alignment(bdev_get_queue(bdev));
705}
706
707#define blk_finished_io(nsects) do { } while (0)
708#define blk_started_io(nsects) do { } while (0)
709
710/* assumes size > 256 */
711static inline unsigned int blksize_bits(unsigned int size)
712{
713 unsigned int bits = 8;
714 do {
715 bits++;
716 size >>= 1;
717 } while (size > 256);
718 return bits;
719}
720
721extern inline unsigned int block_size(struct block_device *bdev)
722{
723 return bdev->bd_block_size;
724}
725
726typedef struct {struct page *v;} Sector;
727
728unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
729
730static inline void put_dev_sector(Sector p)
731{
732 page_cache_release(p.v);
733}
734
735struct work_struct;
736int kblockd_schedule_work(struct work_struct *work);
737void kblockd_flush(void);
738
739#ifdef CONFIG_LBD
740# include <asm/div64.h>
741# define sector_div(a, b) do_div(a, b)
742#else
743# define sector_div(n, b)( \
744{ \
745 int _res; \
746 _res = (n) % (b); \
747 (n) /= (b); \
748 _res; \
749} \
750)
751#endif
752
753#define MODULE_ALIAS_BLOCKDEV(major,minor) \
754 MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
755#define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
756 MODULE_ALIAS("block-major-" __stringify(major) "-*")
757
758
759#endif