1 #ifndef _LINUX_BLKDEV_H
2 #define _LINUX_BLKDEV_H
6 #include <linux/sched.h>
7 #include <linux/major.h>
8 #include <linux/genhd.h>
9 #include <linux/list.h>
10 #include <linux/timer.h>
11 #include <linux/workqueue.h>
12 #include <linux/pagemap.h>
13 #include <linux/backing-dev.h>
14 #include <linux/wait.h>
15 #include <linux/mempool.h>
16 #include <linux/bio.h>
17 #include <linux/module.h>
18 #include <linux/stringify.h>
19 #include <linux/bsg.h>
21 #include <asm/scatterlist.h>
23 struct scsi_ioctl_command;
26 typedef struct request_queue request_queue_t __deprecated;
27 struct elevator_queue;
28 typedef struct elevator_queue elevator_t;
29 struct request_pm_state;
34 #define BLKDEV_MIN_RQ 4
35 #define BLKDEV_MAX_RQ 128 /* Default maximum */
38 * This is the per-process anticipatory I/O scheduler state.
40 struct as_io_context {
43 void (*dtor)(struct as_io_context *aic); /* destructor */
44 void (*exit)(struct as_io_context *aic); /* called on task exit */
47 atomic_t nr_queued; /* queued reads & sync writes */
48 atomic_t nr_dispatched; /* number of requests gone to the drivers */
50 /* IO History tracking */
52 unsigned long last_end_request;
53 unsigned long ttime_total;
54 unsigned long ttime_samples;
55 unsigned long ttime_mean;
57 unsigned int seek_samples;
58 sector_t last_request_pos;
64 struct cfq_io_context {
65 struct rb_node rb_node;
68 struct cfq_queue *cfqq[2];
70 struct io_context *ioc;
72 unsigned long last_end_request;
73 sector_t last_request_pos;
75 unsigned long ttime_total;
76 unsigned long ttime_samples;
77 unsigned long ttime_mean;
79 unsigned int seek_samples;
83 struct list_head queue_list;
85 void (*dtor)(struct io_context *); /* destructor */
86 void (*exit)(struct io_context *); /* called on task exit */
90 * This is the per-process I/O subsystem state. It is refcounted and
91 * kmalloc'ed. Currently all fields are modified in process io context
92 * (apart from the atomic refcount), so require no locking.
96 struct task_struct *task;
98 unsigned int ioprio_changed;
101 * For request batching
103 unsigned long last_waited; /* Time last woken after wait for request */
104 int nr_batch_requests; /* Number of requests left in the batch */
106 struct as_io_context *aic;
107 struct rb_root cic_root;
111 void put_io_context(struct io_context *ioc);
112 void exit_io_context(void);
113 struct io_context *get_io_context(gfp_t gfp_flags, int node);
114 void copy_io_context(struct io_context **pdst, struct io_context **psrc);
115 void swap_io_context(struct io_context **ioc1, struct io_context **ioc2);
118 typedef void (rq_end_io_fn)(struct request *, int);
120 struct request_list {
125 wait_queue_head_t wait[2];
129 * request command types
131 enum rq_cmd_type_bits {
132 REQ_TYPE_FS = 1, /* fs request */
133 REQ_TYPE_BLOCK_PC, /* scsi command */
134 REQ_TYPE_SENSE, /* sense request */
135 REQ_TYPE_PM_SUSPEND, /* suspend request */
136 REQ_TYPE_PM_RESUME, /* resume request */
137 REQ_TYPE_PM_SHUTDOWN, /* shutdown request */
138 REQ_TYPE_FLUSH, /* flush request */
139 REQ_TYPE_SPECIAL, /* driver defined type */
140 REQ_TYPE_LINUX_BLOCK, /* generic block layer message */
142 * for ATA/ATAPI devices. this really doesn't belong here, ide should
143 * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver
144 * private REQ_LB opcodes to differentiate what type of request this is
148 REQ_TYPE_ATA_TASKFILE,
153 * For request of type REQ_TYPE_LINUX_BLOCK, rq->cmd[0] is the opcode being
154 * sent down (similar to how REQ_TYPE_BLOCK_PC means that ->cmd[] holds a
157 * 0x00 -> 0x3f are driver private, to be used for whatever purpose they need,
158 * typically to differentiate REQ_TYPE_SPECIAL requests.
163 * just examples for now
165 REQ_LB_OP_EJECT = 0x40, /* eject request */
166 REQ_LB_OP_FLUSH = 0x41, /* flush device */
170 * request type modified bits. first three bits match BIO_RW* bits, important
173 __REQ_RW, /* not set, read. set, write */
174 __REQ_FAILFAST, /* no low level driver retries */
175 __REQ_SORTED, /* elevator knows about this request */
176 __REQ_SOFTBARRIER, /* may not be passed by ioscheduler */
177 __REQ_HARDBARRIER, /* may not be passed by drive either */
178 __REQ_FUA, /* forced unit access */
179 __REQ_NOMERGE, /* don't touch this for merging */
180 __REQ_STARTED, /* drive already may have started this one */
181 __REQ_DONTPREP, /* don't call prep for this one */
182 __REQ_QUEUED, /* uses queueing */
183 __REQ_ELVPRIV, /* elevator private data attached */
184 __REQ_FAILED, /* set if the request failed */
185 __REQ_QUIET, /* don't worry about errors */
186 __REQ_PREEMPT, /* set for "ide_preempt" requests */
187 __REQ_ORDERED_COLOR, /* is before or after barrier */
188 __REQ_RW_SYNC, /* request is sync (O_DIRECT) */
189 __REQ_ALLOCED, /* request came from our alloc pool */
190 __REQ_RW_META, /* metadata io request */
191 __REQ_NR_BITS, /* stops here */
194 #define REQ_RW (1 << __REQ_RW)
195 #define REQ_FAILFAST (1 << __REQ_FAILFAST)
196 #define REQ_SORTED (1 << __REQ_SORTED)
197 #define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER)
198 #define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER)
199 #define REQ_FUA (1 << __REQ_FUA)
200 #define REQ_NOMERGE (1 << __REQ_NOMERGE)
201 #define REQ_STARTED (1 << __REQ_STARTED)
202 #define REQ_DONTPREP (1 << __REQ_DONTPREP)
203 #define REQ_QUEUED (1 << __REQ_QUEUED)
204 #define REQ_ELVPRIV (1 << __REQ_ELVPRIV)
205 #define REQ_FAILED (1 << __REQ_FAILED)
206 #define REQ_QUIET (1 << __REQ_QUIET)
207 #define REQ_PREEMPT (1 << __REQ_PREEMPT)
208 #define REQ_ORDERED_COLOR (1 << __REQ_ORDERED_COLOR)
209 #define REQ_RW_SYNC (1 << __REQ_RW_SYNC)
210 #define REQ_ALLOCED (1 << __REQ_ALLOCED)
211 #define REQ_RW_META (1 << __REQ_RW_META)
213 #define BLK_MAX_CDB 16
216 * try to put the fields that are referenced together in the same cacheline
219 struct list_head queuelist;
220 struct list_head donelist;
222 struct request_queue *q;
224 unsigned int cmd_flags;
225 enum rq_cmd_type_bits cmd_type;
227 /* Maintain bio traversal state for part by part I/O submission.
228 * hard_* are block layer internals, no driver should touch them!
231 sector_t sector; /* next sector to submit */
232 sector_t hard_sector; /* next sector to complete */
233 unsigned long nr_sectors; /* no. of sectors left to submit */
234 unsigned long hard_nr_sectors; /* no. of sectors left to complete */
235 /* no. of sectors left to submit in the current segment */
236 unsigned int current_nr_sectors;
238 /* no. of sectors left to complete in the current segment */
239 unsigned int hard_cur_sectors;
244 struct hlist_node hash; /* merge hash */
246 * The rb_node is only used inside the io scheduler, requests
247 * are pruned when moved to the dispatch queue. So let the
248 * completion_data share space with the rb_node.
251 struct rb_node rb_node; /* sort/lookup */
252 void *completion_data;
256 * two pointers are available for the IO schedulers, if they need
257 * more they have to dynamically allocate it.
259 void *elevator_private;
260 void *elevator_private2;
262 struct gendisk *rq_disk;
263 unsigned long start_time;
265 /* Number of scatter-gather DMA addr+len pairs after
266 * physical address coalescing is performed.
268 unsigned short nr_phys_segments;
270 /* Number of scatter-gather addr+len pairs after
271 * physical and DMA remapping hardware coalescing is performed.
272 * This is the number of scatter-gather entries the driver
273 * will actually have to deal with after DMA mapping is done.
275 unsigned short nr_hw_segments;
277 unsigned short ioprio;
288 * when request is used as a packet command carrier
290 unsigned int cmd_len;
291 unsigned char cmd[BLK_MAX_CDB];
293 unsigned int data_len;
294 unsigned int sense_len;
298 unsigned int timeout;
302 * completion callback.
304 rq_end_io_fn *end_io;
308 struct request *next_rq;
312 * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
313 * requests. Some step values could eventually be made generic.
315 struct request_pm_state
317 /* PM state machine step value, currently driver specific */
319 /* requested PM state value (S1, S2, S3, S4, ...) */
321 void* data; /* for driver use */
324 #include <linux/elevator.h>
326 typedef void (request_fn_proc) (struct request_queue *q);
327 typedef int (make_request_fn) (struct request_queue *q, struct bio *bio);
328 typedef int (prep_rq_fn) (struct request_queue *, struct request *);
329 typedef void (unplug_fn) (struct request_queue *);
332 typedef int (merge_bvec_fn) (struct request_queue *, struct bio *, struct bio_vec *);
333 typedef void (prepare_flush_fn) (struct request_queue *, struct request *);
334 typedef void (softirq_done_fn)(struct request *);
336 enum blk_queue_state {
341 struct blk_queue_tag {
342 struct request **tag_index; /* map of busy tags */
343 unsigned long *tag_map; /* bit map of free/busy tags */
344 int busy; /* current depth */
345 int max_depth; /* what we will send to device */
346 int real_max_depth; /* what the array can hold */
347 atomic_t refcnt; /* map can be shared */
353 * Together with queue_head for cacheline sharing
355 struct list_head queue_head;
356 struct request *last_merge;
357 elevator_t *elevator;
360 * the queue request freelist, one for reads and one for writes
362 struct request_list rq;
364 request_fn_proc *request_fn;
365 make_request_fn *make_request_fn;
366 prep_rq_fn *prep_rq_fn;
367 unplug_fn *unplug_fn;
368 merge_bvec_fn *merge_bvec_fn;
369 prepare_flush_fn *prepare_flush_fn;
370 softirq_done_fn *softirq_done_fn;
373 * Dispatch queue sorting
376 struct request *boundary_rq;
379 * Auto-unplugging state
381 struct timer_list unplug_timer;
382 int unplug_thresh; /* After this many requests */
383 unsigned long unplug_delay; /* After this many jiffies */
384 struct work_struct unplug_work;
386 struct backing_dev_info backing_dev_info;
389 * The queue owner gets to use this for whatever they like.
390 * ll_rw_blk doesn't touch it.
395 * queue needs bounce pages for pages above this limit
397 unsigned long bounce_pfn;
401 * various queue flags, see QUEUE_* below
403 unsigned long queue_flags;
406 * protects queue structures from reentrancy. ->__queue_lock should
407 * _never_ be used directly, it is queue private. always use
410 spinlock_t __queue_lock;
411 spinlock_t *queue_lock;
421 unsigned long nr_requests; /* Max # of requests */
422 unsigned int nr_congestion_on;
423 unsigned int nr_congestion_off;
424 unsigned int nr_batching;
426 unsigned int max_sectors;
427 unsigned int max_hw_sectors;
428 unsigned short max_phys_segments;
429 unsigned short max_hw_segments;
430 unsigned short hardsect_size;
431 unsigned int max_segment_size;
433 unsigned long seg_boundary_mask;
434 unsigned int dma_alignment;
436 struct blk_queue_tag *queue_tags;
437 struct list_head tag_busy_list;
439 unsigned int nr_sorted;
440 unsigned int in_flight;
445 unsigned int sg_timeout;
446 unsigned int sg_reserved_size;
448 #ifdef CONFIG_BLK_DEV_IO_TRACE
449 struct blk_trace *blk_trace;
452 * reserved for flush operations
454 unsigned int ordered, next_ordered, ordseq;
455 int orderr, ordcolor;
456 struct request pre_flush_rq, bar_rq, post_flush_rq;
457 struct request *orig_bar_rq;
459 struct mutex sysfs_lock;
461 #if defined(CONFIG_BLK_DEV_BSG)
462 struct bsg_class_device bsg_dev;
466 #define QUEUE_FLAG_CLUSTER 0 /* cluster several segments into 1 */
467 #define QUEUE_FLAG_QUEUED 1 /* uses generic tag queueing */
468 #define QUEUE_FLAG_STOPPED 2 /* queue is stopped */
469 #define QUEUE_FLAG_READFULL 3 /* read queue has been filled */
470 #define QUEUE_FLAG_WRITEFULL 4 /* write queue has been filled */
471 #define QUEUE_FLAG_DEAD 5 /* queue being torn down */
472 #define QUEUE_FLAG_REENTER 6 /* Re-entrancy avoidance */
473 #define QUEUE_FLAG_PLUGGED 7 /* queue is plugged */
474 #define QUEUE_FLAG_ELVSWITCH 8 /* don't use elevator, just do FIFO */
475 #define QUEUE_FLAG_BIDI 9 /* queue supports bidi requests */
479 * Hardbarrier is supported with one of the following methods.
481 * NONE : hardbarrier unsupported
482 * DRAIN : ordering by draining is enough
483 * DRAIN_FLUSH : ordering by draining w/ pre and post flushes
484 * DRAIN_FUA : ordering by draining w/ pre flush and FUA write
485 * TAG : ordering by tag is enough
486 * TAG_FLUSH : ordering by tag w/ pre and post flushes
487 * TAG_FUA : ordering by tag w/ pre flush and FUA write
489 QUEUE_ORDERED_NONE = 0x00,
490 QUEUE_ORDERED_DRAIN = 0x01,
491 QUEUE_ORDERED_TAG = 0x02,
493 QUEUE_ORDERED_PREFLUSH = 0x10,
494 QUEUE_ORDERED_POSTFLUSH = 0x20,
495 QUEUE_ORDERED_FUA = 0x40,
497 QUEUE_ORDERED_DRAIN_FLUSH = QUEUE_ORDERED_DRAIN |
498 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
499 QUEUE_ORDERED_DRAIN_FUA = QUEUE_ORDERED_DRAIN |
500 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
501 QUEUE_ORDERED_TAG_FLUSH = QUEUE_ORDERED_TAG |
502 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
503 QUEUE_ORDERED_TAG_FUA = QUEUE_ORDERED_TAG |
504 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
507 * Ordered operation sequence
509 QUEUE_ORDSEQ_STARTED = 0x01, /* flushing in progress */
510 QUEUE_ORDSEQ_DRAIN = 0x02, /* waiting for the queue to be drained */
511 QUEUE_ORDSEQ_PREFLUSH = 0x04, /* pre-flushing in progress */
512 QUEUE_ORDSEQ_BAR = 0x08, /* original barrier req in progress */
513 QUEUE_ORDSEQ_POSTFLUSH = 0x10, /* post-flushing in progress */
514 QUEUE_ORDSEQ_DONE = 0x20,
517 #define blk_queue_plugged(q) test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
518 #define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
519 #define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
520 #define blk_queue_flushing(q) ((q)->ordseq)
522 #define blk_fs_request(rq) ((rq)->cmd_type == REQ_TYPE_FS)
523 #define blk_pc_request(rq) ((rq)->cmd_type == REQ_TYPE_BLOCK_PC)
524 #define blk_special_request(rq) ((rq)->cmd_type == REQ_TYPE_SPECIAL)
525 #define blk_sense_request(rq) ((rq)->cmd_type == REQ_TYPE_SENSE)
527 #define blk_noretry_request(rq) ((rq)->cmd_flags & REQ_FAILFAST)
528 #define blk_rq_started(rq) ((rq)->cmd_flags & REQ_STARTED)
530 #define blk_account_rq(rq) (blk_rq_started(rq) && blk_fs_request(rq))
532 #define blk_pm_suspend_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND)
533 #define blk_pm_resume_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_RESUME)
534 #define blk_pm_request(rq) \
535 (blk_pm_suspend_request(rq) || blk_pm_resume_request(rq))
537 #define blk_sorted_rq(rq) ((rq)->cmd_flags & REQ_SORTED)
538 #define blk_barrier_rq(rq) ((rq)->cmd_flags & REQ_HARDBARRIER)
539 #define blk_fua_rq(rq) ((rq)->cmd_flags & REQ_FUA)
540 #define blk_bidi_rq(rq) ((rq)->next_rq != NULL)
541 #define blk_empty_barrier(rq) (blk_barrier_rq(rq) && blk_fs_request(rq) && !(rq)->hard_nr_sectors)
543 #define list_entry_rq(ptr) list_entry((ptr), struct request, queuelist)
545 #define rq_data_dir(rq) ((rq)->cmd_flags & 1)
548 * We regard a request as sync, if it's a READ or a SYNC write.
550 #define rq_is_sync(rq) (rq_data_dir((rq)) == READ || (rq)->cmd_flags & REQ_RW_SYNC)
551 #define rq_is_meta(rq) ((rq)->cmd_flags & REQ_RW_META)
553 static inline int blk_queue_full(struct request_queue *q, int rw)
556 return test_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
557 return test_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
560 static inline void blk_set_queue_full(struct request_queue *q, int rw)
563 set_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
565 set_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
568 static inline void blk_clear_queue_full(struct request_queue *q, int rw)
571 clear_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
573 clear_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
578 * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
579 * it already be started by driver.
581 #define RQ_NOMERGE_FLAGS \
582 (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER)
583 #define rq_mergeable(rq) \
584 (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && blk_fs_request((rq)))
587 * q->prep_rq_fn return values
589 #define BLKPREP_OK 0 /* serve it */
590 #define BLKPREP_KILL 1 /* fatal error, kill */
591 #define BLKPREP_DEFER 2 /* leave on queue */
593 extern unsigned long blk_max_low_pfn, blk_max_pfn;
596 * standard bounce addresses:
598 * BLK_BOUNCE_HIGH : bounce all highmem pages
599 * BLK_BOUNCE_ANY : don't bounce anything
600 * BLK_BOUNCE_ISA : bounce pages above ISA DMA boundary
602 #define BLK_BOUNCE_HIGH ((u64)blk_max_low_pfn << PAGE_SHIFT)
603 #define BLK_BOUNCE_ANY ((u64)blk_max_pfn << PAGE_SHIFT)
604 #define BLK_BOUNCE_ISA (ISA_DMA_THRESHOLD)
607 * default timeout for SG_IO if none specified
609 #define BLK_DEFAULT_SG_TIMEOUT (60 * HZ)
612 extern int init_emergency_isa_pool(void);
613 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
615 static inline int init_emergency_isa_pool(void)
619 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
622 #endif /* CONFIG_MMU */
624 struct req_iterator {
629 /* This should not be used directly - use rq_for_each_segment */
630 #define __rq_for_each_bio(_bio, rq) \
632 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
634 #define rq_for_each_segment(bvl, _rq, _iter) \
635 __rq_for_each_bio(_iter.bio, _rq) \
636 bio_for_each_segment(bvl, _iter.bio, _iter.i)
638 #define rq_iter_last(rq, _iter) \
639 (_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)
641 extern int blk_register_queue(struct gendisk *disk);
642 extern void blk_unregister_queue(struct gendisk *disk);
643 extern void register_disk(struct gendisk *dev);
644 extern void generic_make_request(struct bio *bio);
645 extern void blk_put_request(struct request *);
646 extern void __blk_put_request(struct request_queue *, struct request *);
647 extern void blk_end_sync_rq(struct request *rq, int error);
648 extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
649 extern void blk_insert_request(struct request_queue *, struct request *, int, void *);
650 extern void blk_requeue_request(struct request_queue *, struct request *);
651 extern void blk_plug_device(struct request_queue *);
652 extern int blk_remove_plug(struct request_queue *);
653 extern void blk_recount_segments(struct request_queue *, struct bio *);
654 extern int scsi_cmd_ioctl(struct file *, struct request_queue *,
655 struct gendisk *, unsigned int, void __user *);
656 extern int sg_scsi_ioctl(struct file *, struct request_queue *,
657 struct gendisk *, struct scsi_ioctl_command __user *);
660 * Temporary export, until SCSI gets fixed up.
662 extern int blk_rq_append_bio(struct request_queue *q, struct request *rq,
666 * A queue has just exitted congestion. Note this in the global counter of
667 * congested queues, and wake up anyone who was waiting for requests to be
670 static inline void blk_clear_queue_congested(struct request_queue *q, int rw)
672 clear_bdi_congested(&q->backing_dev_info, rw);
676 * A queue has just entered congestion. Flag that in the queue's VM-visible
677 * state flags and increment the global gounter of congested queues.
679 static inline void blk_set_queue_congested(struct request_queue *q, int rw)
681 set_bdi_congested(&q->backing_dev_info, rw);
684 extern void blk_start_queue(struct request_queue *q);
685 extern void blk_stop_queue(struct request_queue *q);
686 extern void blk_sync_queue(struct request_queue *q);
687 extern void __blk_stop_queue(struct request_queue *q);
688 extern void blk_run_queue(struct request_queue *);
689 extern void blk_start_queueing(struct request_queue *);
690 extern int blk_rq_map_user(struct request_queue *, struct request *, void __user *, unsigned long);
691 extern int blk_rq_unmap_user(struct bio *);
692 extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
693 extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
694 struct sg_iovec *, int, unsigned int);
695 extern int blk_execute_rq(struct request_queue *, struct gendisk *,
696 struct request *, int);
697 extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
698 struct request *, int, rq_end_io_fn *);
699 extern int blk_verify_command(unsigned char *, int);
700 extern void blk_unplug(struct request_queue *q);
702 static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
704 return bdev->bd_disk->queue;
707 static inline void blk_run_backing_dev(struct backing_dev_info *bdi,
710 if (bdi && bdi->unplug_io_fn)
711 bdi->unplug_io_fn(bdi, page);
714 static inline void blk_run_address_space(struct address_space *mapping)
717 blk_run_backing_dev(mapping->backing_dev_info, NULL);
721 * end_request() and friends. Must be called with the request queue spinlock
722 * acquired. All functions called within end_request() _must_be_ atomic.
724 * Several drivers define their own end_request and call
725 * end_that_request_first() and end_that_request_last()
726 * for parts of the original function. This prevents
727 * code duplication in drivers.
729 extern int end_that_request_first(struct request *, int, int);
730 extern int end_that_request_chunk(struct request *, int, int);
731 extern void end_that_request_last(struct request *, int);
732 extern void end_request(struct request *, int);
733 extern void end_queued_request(struct request *, int);
734 extern void end_dequeued_request(struct request *, int);
735 extern void blk_complete_request(struct request *);
738 * end_that_request_first/chunk() takes an uptodate argument. we account
739 * any value <= as an io error. 0 means -EIO for compatability reasons,
740 * any other < 0 value is the direct error type. An uptodate value of
741 * 1 indicates successful io completion
743 #define end_io_error(uptodate) (unlikely((uptodate) <= 0))
745 static inline void blkdev_dequeue_request(struct request *req)
747 elv_dequeue_request(req->q, req);
751 * Access functions for manipulating queue properties
753 extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
754 spinlock_t *lock, int node_id);
755 extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
756 extern void blk_cleanup_queue(struct request_queue *);
757 extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
758 extern void blk_queue_bounce_limit(struct request_queue *, u64);
759 extern void blk_queue_max_sectors(struct request_queue *, unsigned int);
760 extern void blk_queue_max_phys_segments(struct request_queue *, unsigned short);
761 extern void blk_queue_max_hw_segments(struct request_queue *, unsigned short);
762 extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
763 extern void blk_queue_hardsect_size(struct request_queue *, unsigned short);
764 extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
765 extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
766 extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
767 extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
768 extern void blk_queue_dma_alignment(struct request_queue *, int);
769 extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
770 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
771 extern int blk_queue_ordered(struct request_queue *, unsigned, prepare_flush_fn *);
772 extern int blk_do_ordered(struct request_queue *, struct request **);
773 extern unsigned blk_ordered_cur_seq(struct request_queue *);
774 extern unsigned blk_ordered_req_seq(struct request *);
775 extern void blk_ordered_complete_seq(struct request_queue *, unsigned, int);
777 extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
778 extern void blk_dump_rq_flags(struct request *, char *);
779 extern void generic_unplug_device(struct request_queue *);
780 extern void __generic_unplug_device(struct request_queue *);
781 extern long nr_blockdev_pages(void);
783 int blk_get_queue(struct request_queue *);
784 struct request_queue *blk_alloc_queue(gfp_t);
785 struct request_queue *blk_alloc_queue_node(gfp_t, int);
786 extern void blk_put_queue(struct request_queue *);
791 #define blk_queue_tag_depth(q) ((q)->queue_tags->busy)
792 #define blk_queue_tag_queue(q) ((q)->queue_tags->busy < (q)->queue_tags->max_depth)
793 #define blk_rq_tagged(rq) ((rq)->cmd_flags & REQ_QUEUED)
794 extern int blk_queue_start_tag(struct request_queue *, struct request *);
795 extern struct request *blk_queue_find_tag(struct request_queue *, int);
796 extern void blk_queue_end_tag(struct request_queue *, struct request *);
797 extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *);
798 extern void blk_queue_free_tags(struct request_queue *);
799 extern int blk_queue_resize_tags(struct request_queue *, int);
800 extern void blk_queue_invalidate_tags(struct request_queue *);
801 extern struct blk_queue_tag *blk_init_tags(int);
802 extern void blk_free_tags(struct blk_queue_tag *);
804 static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
807 if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
809 return bqt->tag_index[tag];
812 extern int blkdev_issue_flush(struct block_device *, sector_t *);
814 #define MAX_PHYS_SEGMENTS 128
815 #define MAX_HW_SEGMENTS 128
816 #define SAFE_MAX_SECTORS 255
817 #define BLK_DEF_MAX_SECTORS 1024
819 #define MAX_SEGMENT_SIZE 65536
821 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
823 static inline int queue_hardsect_size(struct request_queue *q)
827 if (q && q->hardsect_size)
828 retval = q->hardsect_size;
833 static inline int bdev_hardsect_size(struct block_device *bdev)
835 return queue_hardsect_size(bdev_get_queue(bdev));
838 static inline int queue_dma_alignment(struct request_queue *q)
842 if (q && q->dma_alignment)
843 retval = q->dma_alignment;
848 /* assumes size > 256 */
849 static inline unsigned int blksize_bits(unsigned int size)
851 unsigned int bits = 8;
855 } while (size > 256);
859 static inline unsigned int block_size(struct block_device *bdev)
861 return bdev->bd_block_size;
864 typedef struct {struct page *v;} Sector;
866 unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
868 static inline void put_dev_sector(Sector p)
870 page_cache_release(p.v);
874 int kblockd_schedule_work(struct work_struct *work);
875 void kblockd_flush_work(struct work_struct *work);
877 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
878 MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
879 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
880 MODULE_ALIAS("block-major-" __stringify(major) "-*")
883 #else /* CONFIG_BLOCK */
885 * stubs for when the block layer is configured out
887 #define buffer_heads_over_limit 0
889 static inline long nr_blockdev_pages(void)
894 static inline void exit_io_context(void)
898 #endif /* CONFIG_BLOCK */