1 #ifndef _LINUX_BLKDEV_H
2 #define _LINUX_BLKDEV_H
4 #include <linux/sched.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>
18 #include <asm/scatterlist.h>
21 # include <asm/div64.h>
22 # define sector_div(a, b) do_div(a, b)
24 # define sector_div(n, b)( \
36 struct scsi_ioctl_command;
39 typedef struct request_queue request_queue_t;
40 struct elevator_queue;
41 typedef struct elevator_queue elevator_t;
42 struct request_pm_state;
47 #define BLKDEV_MIN_RQ 4
48 #define BLKDEV_MAX_RQ 128 /* Default maximum */
51 * This is the per-process anticipatory I/O scheduler state.
53 struct as_io_context {
56 void (*dtor)(struct as_io_context *aic); /* destructor */
57 void (*exit)(struct as_io_context *aic); /* called on task exit */
60 atomic_t nr_queued; /* queued reads & sync writes */
61 atomic_t nr_dispatched; /* number of requests gone to the drivers */
63 /* IO History tracking */
65 unsigned long last_end_request;
66 unsigned long ttime_total;
67 unsigned long ttime_samples;
68 unsigned long ttime_mean;
70 unsigned int seek_samples;
71 sector_t last_request_pos;
77 struct cfq_io_context {
78 struct rb_node rb_node;
81 struct cfq_queue *cfqq[2];
83 struct io_context *ioc;
85 unsigned long last_end_request;
86 sector_t last_request_pos;
88 unsigned long ttime_total;
89 unsigned long ttime_samples;
90 unsigned long ttime_mean;
92 unsigned int seek_samples;
96 struct list_head queue_list;
98 void (*dtor)(struct io_context *); /* destructor */
99 void (*exit)(struct io_context *); /* called on task exit */
103 * This is the per-process I/O subsystem state. It is refcounted and
104 * kmalloc'ed. Currently all fields are modified in process io context
105 * (apart from the atomic refcount), so require no locking.
109 struct task_struct *task;
111 unsigned int ioprio_changed;
114 * For request batching
116 unsigned long last_waited; /* Time last woken after wait for request */
117 int nr_batch_requests; /* Number of requests left in the batch */
119 struct as_io_context *aic;
120 struct rb_root cic_root;
124 void put_io_context(struct io_context *ioc);
125 void exit_io_context(void);
126 struct io_context *get_io_context(gfp_t gfp_flags, int node);
127 void copy_io_context(struct io_context **pdst, struct io_context **psrc);
128 void swap_io_context(struct io_context **ioc1, struct io_context **ioc2);
131 typedef void (rq_end_io_fn)(struct request *, int);
133 struct request_list {
138 wait_queue_head_t wait[2];
142 * request command types
144 enum rq_cmd_type_bits {
145 REQ_TYPE_FS = 1, /* fs request */
146 REQ_TYPE_BLOCK_PC, /* scsi command */
147 REQ_TYPE_SENSE, /* sense request */
148 REQ_TYPE_PM_SUSPEND, /* suspend request */
149 REQ_TYPE_PM_RESUME, /* resume request */
150 REQ_TYPE_PM_SHUTDOWN, /* shutdown request */
151 REQ_TYPE_FLUSH, /* flush request */
152 REQ_TYPE_SPECIAL, /* driver defined type */
153 REQ_TYPE_LINUX_BLOCK, /* generic block layer message */
155 * for ATA/ATAPI devices. this really doesn't belong here, ide should
156 * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver
157 * private REQ_LB opcodes to differentiate what type of request this is
161 REQ_TYPE_ATA_TASKFILE,
166 * For request of type REQ_TYPE_LINUX_BLOCK, rq->cmd[0] is the opcode being
167 * sent down (similar to how REQ_TYPE_BLOCK_PC means that ->cmd[] holds a
170 * 0x00 -> 0x3f are driver private, to be used for whatever purpose they need,
171 * typically to differentiate REQ_TYPE_SPECIAL requests.
176 * just examples for now
178 REQ_LB_OP_EJECT = 0x40, /* eject request */
179 REQ_LB_OP_FLUSH = 0x41, /* flush device */
183 * request type modified bits. first three bits match BIO_RW* bits, important
186 __REQ_RW, /* not set, read. set, write */
187 __REQ_FAILFAST, /* no low level driver retries */
188 __REQ_SORTED, /* elevator knows about this request */
189 __REQ_SOFTBARRIER, /* may not be passed by ioscheduler */
190 __REQ_HARDBARRIER, /* may not be passed by drive either */
191 __REQ_FUA, /* forced unit access */
192 __REQ_NOMERGE, /* don't touch this for merging */
193 __REQ_STARTED, /* drive already may have started this one */
194 __REQ_DONTPREP, /* don't call prep for this one */
195 __REQ_QUEUED, /* uses queueing */
196 __REQ_ELVPRIV, /* elevator private data attached */
197 __REQ_FAILED, /* set if the request failed */
198 __REQ_QUIET, /* don't worry about errors */
199 __REQ_PREEMPT, /* set for "ide_preempt" requests */
200 __REQ_ORDERED_COLOR, /* is before or after barrier */
201 __REQ_RW_SYNC, /* request is sync (O_DIRECT) */
202 __REQ_ALLOCED, /* request came from our alloc pool */
203 __REQ_RW_META, /* metadata io request */
204 __REQ_NR_BITS, /* stops here */
207 #define REQ_RW (1 << __REQ_RW)
208 #define REQ_FAILFAST (1 << __REQ_FAILFAST)
209 #define REQ_SORTED (1 << __REQ_SORTED)
210 #define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER)
211 #define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER)
212 #define REQ_FUA (1 << __REQ_FUA)
213 #define REQ_NOMERGE (1 << __REQ_NOMERGE)
214 #define REQ_STARTED (1 << __REQ_STARTED)
215 #define REQ_DONTPREP (1 << __REQ_DONTPREP)
216 #define REQ_QUEUED (1 << __REQ_QUEUED)
217 #define REQ_ELVPRIV (1 << __REQ_ELVPRIV)
218 #define REQ_FAILED (1 << __REQ_FAILED)
219 #define REQ_QUIET (1 << __REQ_QUIET)
220 #define REQ_PREEMPT (1 << __REQ_PREEMPT)
221 #define REQ_ORDERED_COLOR (1 << __REQ_ORDERED_COLOR)
222 #define REQ_RW_SYNC (1 << __REQ_RW_SYNC)
223 #define REQ_ALLOCED (1 << __REQ_ALLOCED)
224 #define REQ_RW_META (1 << __REQ_RW_META)
226 #define BLK_MAX_CDB 16
229 * try to put the fields that are referenced together in the same cacheline
232 struct list_head queuelist;
233 struct list_head donelist;
237 unsigned int cmd_flags;
238 enum rq_cmd_type_bits cmd_type;
240 /* Maintain bio traversal state for part by part I/O submission.
241 * hard_* are block layer internals, no driver should touch them!
244 sector_t sector; /* next sector to submit */
245 sector_t hard_sector; /* next sector to complete */
246 unsigned long nr_sectors; /* no. of sectors left to submit */
247 unsigned long hard_nr_sectors; /* no. of sectors left to complete */
248 /* no. of sectors left to submit in the current segment */
249 unsigned int current_nr_sectors;
251 /* no. of sectors left to complete in the current segment */
252 unsigned int hard_cur_sectors;
257 struct hlist_node hash; /* merge hash */
259 * The rb_node is only used inside the io scheduler, requests
260 * are pruned when moved to the dispatch queue. So let the
261 * completion_data share space with the rb_node.
264 struct rb_node rb_node; /* sort/lookup */
265 void *completion_data;
269 * two pointers are available for the IO schedulers, if they need
270 * more they have to dynamically allocate it.
272 void *elevator_private;
273 void *elevator_private2;
275 struct gendisk *rq_disk;
276 unsigned long start_time;
278 /* Number of scatter-gather DMA addr+len pairs after
279 * physical address coalescing is performed.
281 unsigned short nr_phys_segments;
283 /* Number of scatter-gather addr+len pairs after
284 * physical and DMA remapping hardware coalescing is performed.
285 * This is the number of scatter-gather entries the driver
286 * will actually have to deal with after DMA mapping is done.
288 unsigned short nr_hw_segments;
290 unsigned short ioprio;
301 * when request is used as a packet command carrier
303 unsigned int cmd_len;
304 unsigned char cmd[BLK_MAX_CDB];
306 unsigned int data_len;
307 unsigned int sense_len;
311 unsigned int timeout;
315 * completion callback.
317 rq_end_io_fn *end_io;
322 * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
323 * requests. Some step values could eventually be made generic.
325 struct request_pm_state
327 /* PM state machine step value, currently driver specific */
329 /* requested PM state value (S1, S2, S3, S4, ...) */
331 void* data; /* for driver use */
334 #include <linux/elevator.h>
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 int (issue_flush_fn) (request_queue_t *, struct gendisk *, sector_t *);
344 typedef void (prepare_flush_fn) (request_queue_t *, struct request *);
345 typedef void (softirq_done_fn)(struct request *);
347 enum blk_queue_state {
352 struct blk_queue_tag {
353 struct request **tag_index; /* map of busy tags */
354 unsigned long *tag_map; /* bit map of free/busy tags */
355 struct list_head busy_list; /* fifo list of busy tags */
356 int busy; /* current depth */
357 int max_depth; /* what we will send to device */
358 int real_max_depth; /* what the array can hold */
359 atomic_t refcnt; /* map can be shared */
365 * Together with queue_head for cacheline sharing
367 struct list_head queue_head;
368 struct request *last_merge;
369 elevator_t *elevator;
372 * the queue request freelist, one for reads and one for writes
374 struct request_list rq;
376 request_fn_proc *request_fn;
377 make_request_fn *make_request_fn;
378 prep_rq_fn *prep_rq_fn;
379 unplug_fn *unplug_fn;
380 merge_bvec_fn *merge_bvec_fn;
381 issue_flush_fn *issue_flush_fn;
382 prepare_flush_fn *prepare_flush_fn;
383 softirq_done_fn *softirq_done_fn;
386 * Dispatch queue sorting
389 struct request *boundary_rq;
392 * Auto-unplugging state
394 struct timer_list unplug_timer;
395 int unplug_thresh; /* After this many requests */
396 unsigned long unplug_delay; /* After this many jiffies */
397 struct work_struct unplug_work;
399 struct backing_dev_info backing_dev_info;
402 * The queue owner gets to use this for whatever they like.
403 * ll_rw_blk doesn't touch it.
408 * queue needs bounce pages for pages above this limit
410 unsigned long bounce_pfn;
414 * various queue flags, see QUEUE_* below
416 unsigned long queue_flags;
419 * protects queue structures from reentrancy. ->__queue_lock should
420 * _never_ be used directly, it is queue private. always use
423 spinlock_t __queue_lock;
424 spinlock_t *queue_lock;
434 unsigned long nr_requests; /* Max # of requests */
435 unsigned int nr_congestion_on;
436 unsigned int nr_congestion_off;
437 unsigned int nr_batching;
439 unsigned int max_sectors;
440 unsigned int max_hw_sectors;
441 unsigned short max_phys_segments;
442 unsigned short max_hw_segments;
443 unsigned short hardsect_size;
444 unsigned int max_segment_size;
446 unsigned long seg_boundary_mask;
447 unsigned int dma_alignment;
449 struct blk_queue_tag *queue_tags;
451 unsigned int nr_sorted;
452 unsigned int in_flight;
457 unsigned int sg_timeout;
458 unsigned int sg_reserved_size;
460 #ifdef CONFIG_BLK_DEV_IO_TRACE
461 struct blk_trace *blk_trace;
464 * reserved for flush operations
466 unsigned int ordered, next_ordered, ordseq;
467 int orderr, ordcolor;
468 struct request pre_flush_rq, bar_rq, post_flush_rq;
469 struct request *orig_bar_rq;
470 unsigned int bi_size;
472 struct mutex sysfs_lock;
475 #define QUEUE_FLAG_CLUSTER 0 /* cluster several segments into 1 */
476 #define QUEUE_FLAG_QUEUED 1 /* uses generic tag queueing */
477 #define QUEUE_FLAG_STOPPED 2 /* queue is stopped */
478 #define QUEUE_FLAG_READFULL 3 /* write queue has been filled */
479 #define QUEUE_FLAG_WRITEFULL 4 /* read queue has been filled */
480 #define QUEUE_FLAG_DEAD 5 /* queue being torn down */
481 #define QUEUE_FLAG_REENTER 6 /* Re-entrancy avoidance */
482 #define QUEUE_FLAG_PLUGGED 7 /* queue is plugged */
483 #define QUEUE_FLAG_ELVSWITCH 8 /* don't use elevator, just do FIFO */
487 * Hardbarrier is supported with one of the following methods.
489 * NONE : hardbarrier unsupported
490 * DRAIN : ordering by draining is enough
491 * DRAIN_FLUSH : ordering by draining w/ pre and post flushes
492 * DRAIN_FUA : ordering by draining w/ pre flush and FUA write
493 * TAG : ordering by tag is enough
494 * TAG_FLUSH : ordering by tag w/ pre and post flushes
495 * TAG_FUA : ordering by tag w/ pre flush and FUA write
497 QUEUE_ORDERED_NONE = 0x00,
498 QUEUE_ORDERED_DRAIN = 0x01,
499 QUEUE_ORDERED_TAG = 0x02,
501 QUEUE_ORDERED_PREFLUSH = 0x10,
502 QUEUE_ORDERED_POSTFLUSH = 0x20,
503 QUEUE_ORDERED_FUA = 0x40,
505 QUEUE_ORDERED_DRAIN_FLUSH = QUEUE_ORDERED_DRAIN |
506 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
507 QUEUE_ORDERED_DRAIN_FUA = QUEUE_ORDERED_DRAIN |
508 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
509 QUEUE_ORDERED_TAG_FLUSH = QUEUE_ORDERED_TAG |
510 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
511 QUEUE_ORDERED_TAG_FUA = QUEUE_ORDERED_TAG |
512 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
515 * Ordered operation sequence
517 QUEUE_ORDSEQ_STARTED = 0x01, /* flushing in progress */
518 QUEUE_ORDSEQ_DRAIN = 0x02, /* waiting for the queue to be drained */
519 QUEUE_ORDSEQ_PREFLUSH = 0x04, /* pre-flushing in progress */
520 QUEUE_ORDSEQ_BAR = 0x08, /* original barrier req in progress */
521 QUEUE_ORDSEQ_POSTFLUSH = 0x10, /* post-flushing in progress */
522 QUEUE_ORDSEQ_DONE = 0x20,
525 #define blk_queue_plugged(q) test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
526 #define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
527 #define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
528 #define blk_queue_flushing(q) ((q)->ordseq)
530 #define blk_fs_request(rq) ((rq)->cmd_type == REQ_TYPE_FS)
531 #define blk_pc_request(rq) ((rq)->cmd_type == REQ_TYPE_BLOCK_PC)
532 #define blk_special_request(rq) ((rq)->cmd_type == REQ_TYPE_SPECIAL)
533 #define blk_sense_request(rq) ((rq)->cmd_type == REQ_TYPE_SENSE)
535 #define blk_noretry_request(rq) ((rq)->cmd_flags & REQ_FAILFAST)
536 #define blk_rq_started(rq) ((rq)->cmd_flags & REQ_STARTED)
538 #define blk_account_rq(rq) (blk_rq_started(rq) && blk_fs_request(rq))
540 #define blk_pm_suspend_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND)
541 #define blk_pm_resume_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_RESUME)
542 #define blk_pm_request(rq) \
543 (blk_pm_suspend_request(rq) || blk_pm_resume_request(rq))
545 #define blk_sorted_rq(rq) ((rq)->cmd_flags & REQ_SORTED)
546 #define blk_barrier_rq(rq) ((rq)->cmd_flags & REQ_HARDBARRIER)
547 #define blk_fua_rq(rq) ((rq)->cmd_flags & REQ_FUA)
549 #define list_entry_rq(ptr) list_entry((ptr), struct request, queuelist)
551 #define rq_data_dir(rq) ((rq)->cmd_flags & 1)
554 * We regard a request as sync, if it's a READ or a SYNC write.
556 #define rq_is_sync(rq) (rq_data_dir((rq)) == READ || (rq)->cmd_flags & REQ_RW_SYNC)
557 #define rq_is_meta(rq) ((rq)->cmd_flags & REQ_RW_META)
559 static inline int blk_queue_full(struct request_queue *q, int rw)
562 return test_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
563 return test_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
566 static inline void blk_set_queue_full(struct request_queue *q, int rw)
569 set_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
571 set_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
574 static inline void blk_clear_queue_full(struct request_queue *q, int rw)
577 clear_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
579 clear_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
584 * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
585 * it already be started by driver.
587 #define RQ_NOMERGE_FLAGS \
588 (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER)
589 #define rq_mergeable(rq) \
590 (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && blk_fs_request((rq)))
593 * q->prep_rq_fn return values
595 #define BLKPREP_OK 0 /* serve it */
596 #define BLKPREP_KILL 1 /* fatal error, kill */
597 #define BLKPREP_DEFER 2 /* leave on queue */
599 extern unsigned long blk_max_low_pfn, blk_max_pfn;
602 * standard bounce addresses:
604 * BLK_BOUNCE_HIGH : bounce all highmem pages
605 * BLK_BOUNCE_ANY : don't bounce anything
606 * BLK_BOUNCE_ISA : bounce pages above ISA DMA boundary
608 #define BLK_BOUNCE_HIGH ((u64)blk_max_low_pfn << PAGE_SHIFT)
609 #define BLK_BOUNCE_ANY ((u64)blk_max_pfn << PAGE_SHIFT)
610 #define BLK_BOUNCE_ISA (ISA_DMA_THRESHOLD)
613 * default timeout for SG_IO if none specified
615 #define BLK_DEFAULT_SG_TIMEOUT (60 * HZ)
618 extern int init_emergency_isa_pool(void);
619 extern void blk_queue_bounce(request_queue_t *q, struct bio **bio);
621 static inline int init_emergency_isa_pool(void)
625 static inline void blk_queue_bounce(request_queue_t *q, struct bio **bio)
628 #endif /* CONFIG_MMU */
630 #define rq_for_each_bio(_bio, rq) \
632 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
634 extern int blk_register_queue(struct gendisk *disk);
635 extern void blk_unregister_queue(struct gendisk *disk);
636 extern void register_disk(struct gendisk *dev);
637 extern void generic_make_request(struct bio *bio);
638 extern void blk_put_request(struct request *);
639 extern void __blk_put_request(request_queue_t *, struct request *);
640 extern void blk_end_sync_rq(struct request *rq, int error);
641 extern struct request *blk_get_request(request_queue_t *, int, gfp_t);
642 extern void blk_insert_request(request_queue_t *, struct request *, int, void *);
643 extern void blk_requeue_request(request_queue_t *, struct request *);
644 extern void blk_plug_device(request_queue_t *);
645 extern int blk_remove_plug(request_queue_t *);
646 extern void blk_recount_segments(request_queue_t *, struct bio *);
647 extern int scsi_cmd_ioctl(struct file *, struct request_queue *,
648 struct gendisk *, unsigned int, void __user *);
649 extern int sg_scsi_ioctl(struct file *, struct request_queue *,
650 struct gendisk *, struct scsi_ioctl_command __user *);
653 * Temporary export, until SCSI gets fixed up.
655 extern int ll_back_merge_fn(request_queue_t *, struct request *, struct bio *);
658 * A queue has just exitted congestion. Note this in the global counter of
659 * congested queues, and wake up anyone who was waiting for requests to be
662 static inline void blk_clear_queue_congested(request_queue_t *q, int rw)
664 clear_bdi_congested(&q->backing_dev_info, rw);
668 * A queue has just entered congestion. Flag that in the queue's VM-visible
669 * state flags and increment the global gounter of congested queues.
671 static inline void blk_set_queue_congested(request_queue_t *q, int rw)
673 set_bdi_congested(&q->backing_dev_info, rw);
676 extern void blk_start_queue(request_queue_t *q);
677 extern void blk_stop_queue(request_queue_t *q);
678 extern void blk_sync_queue(struct request_queue *q);
679 extern void __blk_stop_queue(request_queue_t *q);
680 extern void blk_run_queue(request_queue_t *);
681 extern void blk_start_queueing(request_queue_t *);
682 extern int blk_rq_map_user(request_queue_t *, struct request *, void __user *, unsigned long);
683 extern int blk_rq_unmap_user(struct bio *);
684 extern int blk_rq_map_kern(request_queue_t *, struct request *, void *, unsigned int, gfp_t);
685 extern int blk_rq_map_user_iov(request_queue_t *, struct request *,
686 struct sg_iovec *, int, unsigned int);
687 extern int blk_execute_rq(request_queue_t *, struct gendisk *,
688 struct request *, int);
689 extern void blk_execute_rq_nowait(request_queue_t *, struct gendisk *,
690 struct request *, int, rq_end_io_fn *);
691 extern int blk_fill_sghdr_rq(request_queue_t *, struct request *,
692 struct sg_io_hdr *, int);
693 extern int blk_unmap_sghdr_rq(struct request *, struct sg_io_hdr *);
694 extern int blk_complete_sghdr_rq(struct request *, struct sg_io_hdr *,
696 extern int blk_verify_command(unsigned char *, int);
698 static inline request_queue_t *bdev_get_queue(struct block_device *bdev)
700 return bdev->bd_disk->queue;
703 static inline void blk_run_backing_dev(struct backing_dev_info *bdi,
706 if (bdi && bdi->unplug_io_fn)
707 bdi->unplug_io_fn(bdi, page);
710 static inline void blk_run_address_space(struct address_space *mapping)
713 blk_run_backing_dev(mapping->backing_dev_info, NULL);
717 * end_request() and friends. Must be called with the request queue spinlock
718 * acquired. All functions called within end_request() _must_be_ atomic.
720 * Several drivers define their own end_request and call
721 * end_that_request_first() and end_that_request_last()
722 * for parts of the original function. This prevents
723 * code duplication in drivers.
725 extern int end_that_request_first(struct request *, int, int);
726 extern int end_that_request_chunk(struct request *, int, int);
727 extern void end_that_request_last(struct request *, int);
728 extern void end_request(struct request *req, int uptodate);
729 extern void blk_complete_request(struct request *);
732 * end_that_request_first/chunk() takes an uptodate argument. we account
733 * any value <= as an io error. 0 means -EIO for compatability reasons,
734 * any other < 0 value is the direct error type. An uptodate value of
735 * 1 indicates successful io completion
737 #define end_io_error(uptodate) (unlikely((uptodate) <= 0))
739 static inline void blkdev_dequeue_request(struct request *req)
741 elv_dequeue_request(req->q, req);
745 * Access functions for manipulating queue properties
747 extern request_queue_t *blk_init_queue_node(request_fn_proc *rfn,
748 spinlock_t *lock, int node_id);
749 extern request_queue_t *blk_init_queue(request_fn_proc *, spinlock_t *);
750 extern void blk_cleanup_queue(request_queue_t *);
751 extern void blk_queue_make_request(request_queue_t *, make_request_fn *);
752 extern void blk_queue_bounce_limit(request_queue_t *, u64);
753 extern void blk_queue_max_sectors(request_queue_t *, unsigned int);
754 extern void blk_queue_max_phys_segments(request_queue_t *, unsigned short);
755 extern void blk_queue_max_hw_segments(request_queue_t *, unsigned short);
756 extern void blk_queue_max_segment_size(request_queue_t *, unsigned int);
757 extern void blk_queue_hardsect_size(request_queue_t *, unsigned short);
758 extern void blk_queue_stack_limits(request_queue_t *t, request_queue_t *b);
759 extern void blk_queue_segment_boundary(request_queue_t *, unsigned long);
760 extern void blk_queue_prep_rq(request_queue_t *, prep_rq_fn *pfn);
761 extern void blk_queue_merge_bvec(request_queue_t *, merge_bvec_fn *);
762 extern void blk_queue_dma_alignment(request_queue_t *, int);
763 extern void blk_queue_softirq_done(request_queue_t *, softirq_done_fn *);
764 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
765 extern int blk_queue_ordered(request_queue_t *, unsigned, prepare_flush_fn *);
766 extern void blk_queue_issue_flush_fn(request_queue_t *, issue_flush_fn *);
767 extern int blk_do_ordered(request_queue_t *, struct request **);
768 extern unsigned blk_ordered_cur_seq(request_queue_t *);
769 extern unsigned blk_ordered_req_seq(struct request *);
770 extern void blk_ordered_complete_seq(request_queue_t *, unsigned, int);
772 extern int blk_rq_map_sg(request_queue_t *, struct request *, struct scatterlist *);
773 extern void blk_dump_rq_flags(struct request *, char *);
774 extern void generic_unplug_device(request_queue_t *);
775 extern void __generic_unplug_device(request_queue_t *);
776 extern long nr_blockdev_pages(void);
778 int blk_get_queue(request_queue_t *);
779 request_queue_t *blk_alloc_queue(gfp_t);
780 request_queue_t *blk_alloc_queue_node(gfp_t, int);
781 extern void blk_put_queue(request_queue_t *);
786 #define blk_queue_tag_depth(q) ((q)->queue_tags->busy)
787 #define blk_queue_tag_queue(q) ((q)->queue_tags->busy < (q)->queue_tags->max_depth)
788 #define blk_rq_tagged(rq) ((rq)->cmd_flags & REQ_QUEUED)
789 extern int blk_queue_start_tag(request_queue_t *, struct request *);
790 extern struct request *blk_queue_find_tag(request_queue_t *, int);
791 extern void blk_queue_end_tag(request_queue_t *, struct request *);
792 extern int blk_queue_init_tags(request_queue_t *, int, struct blk_queue_tag *);
793 extern void blk_queue_free_tags(request_queue_t *);
794 extern int blk_queue_resize_tags(request_queue_t *, int);
795 extern void blk_queue_invalidate_tags(request_queue_t *);
796 extern struct blk_queue_tag *blk_init_tags(int);
797 extern void blk_free_tags(struct blk_queue_tag *);
799 static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
802 if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
804 return bqt->tag_index[tag];
807 extern void blk_rq_bio_prep(request_queue_t *, struct request *, struct bio *);
808 extern int blkdev_issue_flush(struct block_device *, sector_t *);
810 #define MAX_PHYS_SEGMENTS 128
811 #define MAX_HW_SEGMENTS 128
812 #define SAFE_MAX_SECTORS 255
813 #define BLK_DEF_MAX_SECTORS 1024
815 #define MAX_SEGMENT_SIZE 65536
817 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
819 static inline int queue_hardsect_size(request_queue_t *q)
823 if (q && q->hardsect_size)
824 retval = q->hardsect_size;
829 static inline int bdev_hardsect_size(struct block_device *bdev)
831 return queue_hardsect_size(bdev_get_queue(bdev));
834 static inline int queue_dma_alignment(request_queue_t *q)
838 if (q && q->dma_alignment)
839 retval = q->dma_alignment;
844 /* assumes size > 256 */
845 static inline unsigned int blksize_bits(unsigned int size)
847 unsigned int bits = 8;
851 } while (size > 256);
855 static inline unsigned int block_size(struct block_device *bdev)
857 return bdev->bd_block_size;
860 typedef struct {struct page *v;} Sector;
862 unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
864 static inline void put_dev_sector(Sector p)
866 page_cache_release(p.v);
870 int kblockd_schedule_work(struct work_struct *work);
871 void kblockd_flush_work(struct work_struct *work);
873 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
874 MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
875 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
876 MODULE_ALIAS("block-major-" __stringify(major) "-*")
879 #else /* CONFIG_BLOCK */
881 * stubs for when the block layer is configured out
883 #define buffer_heads_over_limit 0
885 static inline long nr_blockdev_pages(void)
890 static inline void exit_io_context(void)
894 #endif /* CONFIG_BLOCK */