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CommitLineData
1da177e4
LT
1#ifndef _LINUX_BLKDEV_H
2#define _LINUX_BLKDEV_H
3
f5ff8422
JA
4#ifdef CONFIG_BLOCK
5
bcfd8d36 6#include <linux/sched.h>
1da177e4
LT
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>
d351af01 19#include <linux/bsg.h>
1da177e4
LT
20
21#include <asm/scatterlist.h>
22
21b2f0c8
CH
23struct scsi_ioctl_command;
24
1da177e4 25struct request_queue;
71f65e6b 26typedef struct request_queue request_queue_t __deprecated;
1da177e4
LT
27struct elevator_queue;
28typedef struct elevator_queue elevator_t;
29struct request_pm_state;
2056a782 30struct blk_trace;
3d6392cf
JA
31struct request;
32struct sg_io_hdr;
1da177e4
LT
33
34#define BLKDEV_MIN_RQ 4
35#define BLKDEV_MAX_RQ 128 /* Default maximum */
36
d38ecf93 37int put_io_context(struct io_context *ioc);
1da177e4 38void exit_io_context(void);
b5deef90 39struct io_context *get_io_context(gfp_t gfp_flags, int node);
fd0928df 40struct io_context *alloc_io_context(gfp_t gfp_flags, int node);
1da177e4
LT
41void copy_io_context(struct io_context **pdst, struct io_context **psrc);
42void swap_io_context(struct io_context **ioc1, struct io_context **ioc2);
43
44struct request;
8ffdc655 45typedef void (rq_end_io_fn)(struct request *, int);
1da177e4
LT
46
47struct request_list {
48 int count[2];
49 int starved[2];
cb98fc8b 50 int elvpriv;
1da177e4
LT
51 mempool_t *rq_pool;
52 wait_queue_head_t wait[2];
1da177e4
LT
53};
54
4aff5e23
JA
55/*
56 * request command types
57 */
58enum rq_cmd_type_bits {
59 REQ_TYPE_FS = 1, /* fs request */
60 REQ_TYPE_BLOCK_PC, /* scsi command */
61 REQ_TYPE_SENSE, /* sense request */
62 REQ_TYPE_PM_SUSPEND, /* suspend request */
63 REQ_TYPE_PM_RESUME, /* resume request */
64 REQ_TYPE_PM_SHUTDOWN, /* shutdown request */
65 REQ_TYPE_FLUSH, /* flush request */
66 REQ_TYPE_SPECIAL, /* driver defined type */
67 REQ_TYPE_LINUX_BLOCK, /* generic block layer message */
68 /*
69 * for ATA/ATAPI devices. this really doesn't belong here, ide should
70 * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver
71 * private REQ_LB opcodes to differentiate what type of request this is
72 */
4aff5e23 73 REQ_TYPE_ATA_TASKFILE,
cea2885a 74 REQ_TYPE_ATA_PC,
4aff5e23
JA
75};
76
77/*
78 * For request of type REQ_TYPE_LINUX_BLOCK, rq->cmd[0] is the opcode being
79 * sent down (similar to how REQ_TYPE_BLOCK_PC means that ->cmd[] holds a
80 * SCSI cdb.
81 *
82 * 0x00 -> 0x3f are driver private, to be used for whatever purpose they need,
83 * typically to differentiate REQ_TYPE_SPECIAL requests.
84 *
85 */
86enum {
87 /*
88 * just examples for now
89 */
90 REQ_LB_OP_EJECT = 0x40, /* eject request */
91 REQ_LB_OP_FLUSH = 0x41, /* flush device */
92};
93
94/*
95 * request type modified bits. first three bits match BIO_RW* bits, important
96 */
97enum rq_flag_bits {
98 __REQ_RW, /* not set, read. set, write */
99 __REQ_FAILFAST, /* no low level driver retries */
100 __REQ_SORTED, /* elevator knows about this request */
101 __REQ_SOFTBARRIER, /* may not be passed by ioscheduler */
102 __REQ_HARDBARRIER, /* may not be passed by drive either */
103 __REQ_FUA, /* forced unit access */
104 __REQ_NOMERGE, /* don't touch this for merging */
105 __REQ_STARTED, /* drive already may have started this one */
106 __REQ_DONTPREP, /* don't call prep for this one */
107 __REQ_QUEUED, /* uses queueing */
108 __REQ_ELVPRIV, /* elevator private data attached */
109 __REQ_FAILED, /* set if the request failed */
110 __REQ_QUIET, /* don't worry about errors */
111 __REQ_PREEMPT, /* set for "ide_preempt" requests */
112 __REQ_ORDERED_COLOR, /* is before or after barrier */
113 __REQ_RW_SYNC, /* request is sync (O_DIRECT) */
49171e5c 114 __REQ_ALLOCED, /* request came from our alloc pool */
5404bc7a 115 __REQ_RW_META, /* metadata io request */
4aff5e23
JA
116 __REQ_NR_BITS, /* stops here */
117};
118
119#define REQ_RW (1 << __REQ_RW)
120#define REQ_FAILFAST (1 << __REQ_FAILFAST)
121#define REQ_SORTED (1 << __REQ_SORTED)
122#define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER)
123#define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER)
124#define REQ_FUA (1 << __REQ_FUA)
125#define REQ_NOMERGE (1 << __REQ_NOMERGE)
126#define REQ_STARTED (1 << __REQ_STARTED)
127#define REQ_DONTPREP (1 << __REQ_DONTPREP)
128#define REQ_QUEUED (1 << __REQ_QUEUED)
129#define REQ_ELVPRIV (1 << __REQ_ELVPRIV)
130#define REQ_FAILED (1 << __REQ_FAILED)
131#define REQ_QUIET (1 << __REQ_QUIET)
132#define REQ_PREEMPT (1 << __REQ_PREEMPT)
133#define REQ_ORDERED_COLOR (1 << __REQ_ORDERED_COLOR)
134#define REQ_RW_SYNC (1 << __REQ_RW_SYNC)
49171e5c 135#define REQ_ALLOCED (1 << __REQ_ALLOCED)
5404bc7a 136#define REQ_RW_META (1 << __REQ_RW_META)
4aff5e23 137
1da177e4
LT
138#define BLK_MAX_CDB 16
139
140/*
141 * try to put the fields that are referenced together in the same cacheline
142 */
143struct request {
ff856bad
JA
144 struct list_head queuelist;
145 struct list_head donelist;
146
165125e1 147 struct request_queue *q;
e6a1c874 148
4aff5e23
JA
149 unsigned int cmd_flags;
150 enum rq_cmd_type_bits cmd_type;
1da177e4
LT
151
152 /* Maintain bio traversal state for part by part I/O submission.
153 * hard_* are block layer internals, no driver should touch them!
154 */
155
156 sector_t sector; /* next sector to submit */
e6a1c874 157 sector_t hard_sector; /* next sector to complete */
1da177e4 158 unsigned long nr_sectors; /* no. of sectors left to submit */
e6a1c874 159 unsigned long hard_nr_sectors; /* no. of sectors left to complete */
1da177e4
LT
160 /* no. of sectors left to submit in the current segment */
161 unsigned int current_nr_sectors;
162
1da177e4
LT
163 /* no. of sectors left to complete in the current segment */
164 unsigned int hard_cur_sectors;
165
166 struct bio *bio;
167 struct bio *biotail;
168
9817064b 169 struct hlist_node hash; /* merge hash */
e6a1c874
JA
170 /*
171 * The rb_node is only used inside the io scheduler, requests
172 * are pruned when moved to the dispatch queue. So let the
173 * completion_data share space with the rb_node.
174 */
175 union {
176 struct rb_node rb_node; /* sort/lookup */
177 void *completion_data;
178 };
9817064b 179
ff7d145f
JA
180 /*
181 * two pointers are available for the IO schedulers, if they need
182 * more they have to dynamically allocate it.
183 */
1da177e4 184 void *elevator_private;
ff7d145f
JA
185 void *elevator_private2;
186
8f34ee75 187 struct gendisk *rq_disk;
1da177e4
LT
188 unsigned long start_time;
189
190 /* Number of scatter-gather DMA addr+len pairs after
191 * physical address coalescing is performed.
192 */
193 unsigned short nr_phys_segments;
194
195 /* Number of scatter-gather addr+len pairs after
196 * physical and DMA remapping hardware coalescing is performed.
197 * This is the number of scatter-gather entries the driver
198 * will actually have to deal with after DMA mapping is done.
199 */
200 unsigned short nr_hw_segments;
201
8f34ee75
JA
202 unsigned short ioprio;
203
1da177e4 204 void *special;
8f34ee75 205 char *buffer;
1da177e4 206
cdd60262
JA
207 int tag;
208 int errors;
209
210 int ref_count;
211
1da177e4
LT
212 /*
213 * when request is used as a packet command carrier
214 */
215 unsigned int cmd_len;
216 unsigned char cmd[BLK_MAX_CDB];
217
218 unsigned int data_len;
1da177e4 219 unsigned int sense_len;
8f34ee75 220 void *data;
1da177e4
LT
221 void *sense;
222
223 unsigned int timeout;
17e01f21 224 int retries;
1da177e4 225
1da177e4 226 /*
c00895ab 227 * completion callback.
1da177e4
LT
228 */
229 rq_end_io_fn *end_io;
230 void *end_io_data;
abae1fde
FT
231
232 /* for bidi */
233 struct request *next_rq;
1da177e4
LT
234};
235
236/*
4aff5e23 237 * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
1da177e4
LT
238 * requests. Some step values could eventually be made generic.
239 */
240struct request_pm_state
241{
242 /* PM state machine step value, currently driver specific */
243 int pm_step;
244 /* requested PM state value (S1, S2, S3, S4, ...) */
245 u32 pm_state;
246 void* data; /* for driver use */
247};
248
249#include <linux/elevator.h>
250
165125e1
JA
251typedef void (request_fn_proc) (struct request_queue *q);
252typedef int (make_request_fn) (struct request_queue *q, struct bio *bio);
253typedef int (prep_rq_fn) (struct request_queue *, struct request *);
254typedef void (unplug_fn) (struct request_queue *);
1da177e4
LT
255
256struct bio_vec;
165125e1 257typedef int (merge_bvec_fn) (struct request_queue *, struct bio *, struct bio_vec *);
165125e1 258typedef void (prepare_flush_fn) (struct request_queue *, struct request *);
ff856bad 259typedef void (softirq_done_fn)(struct request *);
1da177e4
LT
260
261enum blk_queue_state {
262 Queue_down,
263 Queue_up,
264};
265
1da177e4
LT
266struct blk_queue_tag {
267 struct request **tag_index; /* map of busy tags */
268 unsigned long *tag_map; /* bit map of free/busy tags */
1da177e4
LT
269 int busy; /* current depth */
270 int max_depth; /* what we will send to device */
ba025082 271 int real_max_depth; /* what the array can hold */
1da177e4
LT
272 atomic_t refcnt; /* map can be shared */
273};
274
275struct request_queue
276{
277 /*
278 * Together with queue_head for cacheline sharing
279 */
280 struct list_head queue_head;
281 struct request *last_merge;
282 elevator_t *elevator;
283
284 /*
285 * the queue request freelist, one for reads and one for writes
286 */
287 struct request_list rq;
288
289 request_fn_proc *request_fn;
1da177e4
LT
290 make_request_fn *make_request_fn;
291 prep_rq_fn *prep_rq_fn;
292 unplug_fn *unplug_fn;
293 merge_bvec_fn *merge_bvec_fn;
1da177e4 294 prepare_flush_fn *prepare_flush_fn;
ff856bad 295 softirq_done_fn *softirq_done_fn;
1da177e4 296
8922e16c
TH
297 /*
298 * Dispatch queue sorting
299 */
1b47f531 300 sector_t end_sector;
8922e16c 301 struct request *boundary_rq;
8922e16c 302
1da177e4
LT
303 /*
304 * Auto-unplugging state
305 */
306 struct timer_list unplug_timer;
307 int unplug_thresh; /* After this many requests */
308 unsigned long unplug_delay; /* After this many jiffies */
309 struct work_struct unplug_work;
310
311 struct backing_dev_info backing_dev_info;
312
313 /*
314 * The queue owner gets to use this for whatever they like.
315 * ll_rw_blk doesn't touch it.
316 */
317 void *queuedata;
318
1da177e4
LT
319 /*
320 * queue needs bounce pages for pages above this limit
321 */
322 unsigned long bounce_pfn;
8267e268 323 gfp_t bounce_gfp;
1da177e4
LT
324
325 /*
326 * various queue flags, see QUEUE_* below
327 */
328 unsigned long queue_flags;
329
330 /*
152587de
JA
331 * protects queue structures from reentrancy. ->__queue_lock should
332 * _never_ be used directly, it is queue private. always use
333 * ->queue_lock.
1da177e4 334 */
152587de 335 spinlock_t __queue_lock;
1da177e4
LT
336 spinlock_t *queue_lock;
337
338 /*
339 * queue kobject
340 */
341 struct kobject kobj;
342
343 /*
344 * queue settings
345 */
346 unsigned long nr_requests; /* Max # of requests */
347 unsigned int nr_congestion_on;
348 unsigned int nr_congestion_off;
349 unsigned int nr_batching;
350
2cb2e147
JA
351 unsigned int max_sectors;
352 unsigned int max_hw_sectors;
1da177e4
LT
353 unsigned short max_phys_segments;
354 unsigned short max_hw_segments;
355 unsigned short hardsect_size;
356 unsigned int max_segment_size;
357
358 unsigned long seg_boundary_mask;
fa0ccd83
JB
359 void *dma_drain_buffer;
360 unsigned int dma_drain_size;
1da177e4
LT
361 unsigned int dma_alignment;
362
363 struct blk_queue_tag *queue_tags;
6eca9004 364 struct list_head tag_busy_list;
1da177e4 365
15853af9 366 unsigned int nr_sorted;
1da177e4
LT
367 unsigned int in_flight;
368
369 /*
370 * sg stuff
371 */
372 unsigned int sg_timeout;
373 unsigned int sg_reserved_size;
1946089a 374 int node;
6c5c9341 375#ifdef CONFIG_BLK_DEV_IO_TRACE
2056a782 376 struct blk_trace *blk_trace;
6c5c9341 377#endif
1da177e4
LT
378 /*
379 * reserved for flush operations
380 */
797e7dbb
TH
381 unsigned int ordered, next_ordered, ordseq;
382 int orderr, ordcolor;
383 struct request pre_flush_rq, bar_rq, post_flush_rq;
384 struct request *orig_bar_rq;
483f4afc
AV
385
386 struct mutex sysfs_lock;
d351af01
FT
387
388#if defined(CONFIG_BLK_DEV_BSG)
389 struct bsg_class_device bsg_dev;
390#endif
1da177e4
LT
391};
392
1da177e4
LT
393#define QUEUE_FLAG_CLUSTER 0 /* cluster several segments into 1 */
394#define QUEUE_FLAG_QUEUED 1 /* uses generic tag queueing */
395#define QUEUE_FLAG_STOPPED 2 /* queue is stopped */
4e97182a
QY
396#define QUEUE_FLAG_READFULL 3 /* read queue has been filled */
397#define QUEUE_FLAG_WRITEFULL 4 /* write queue has been filled */
1da177e4
LT
398#define QUEUE_FLAG_DEAD 5 /* queue being torn down */
399#define QUEUE_FLAG_REENTER 6 /* Re-entrancy avoidance */
400#define QUEUE_FLAG_PLUGGED 7 /* queue is plugged */
64521d1a 401#define QUEUE_FLAG_ELVSWITCH 8 /* don't use elevator, just do FIFO */
abae1fde 402#define QUEUE_FLAG_BIDI 9 /* queue supports bidi requests */
797e7dbb
TH
403
404enum {
405 /*
406 * Hardbarrier is supported with one of the following methods.
407 *
408 * NONE : hardbarrier unsupported
409 * DRAIN : ordering by draining is enough
410 * DRAIN_FLUSH : ordering by draining w/ pre and post flushes
411 * DRAIN_FUA : ordering by draining w/ pre flush and FUA write
412 * TAG : ordering by tag is enough
413 * TAG_FLUSH : ordering by tag w/ pre and post flushes
414 * TAG_FUA : ordering by tag w/ pre flush and FUA write
415 */
416 QUEUE_ORDERED_NONE = 0x00,
417 QUEUE_ORDERED_DRAIN = 0x01,
418 QUEUE_ORDERED_TAG = 0x02,
419
420 QUEUE_ORDERED_PREFLUSH = 0x10,
421 QUEUE_ORDERED_POSTFLUSH = 0x20,
422 QUEUE_ORDERED_FUA = 0x40,
423
424 QUEUE_ORDERED_DRAIN_FLUSH = QUEUE_ORDERED_DRAIN |
425 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
426 QUEUE_ORDERED_DRAIN_FUA = QUEUE_ORDERED_DRAIN |
427 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
428 QUEUE_ORDERED_TAG_FLUSH = QUEUE_ORDERED_TAG |
429 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
430 QUEUE_ORDERED_TAG_FUA = QUEUE_ORDERED_TAG |
431 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
432
433 /*
434 * Ordered operation sequence
435 */
436 QUEUE_ORDSEQ_STARTED = 0x01, /* flushing in progress */
437 QUEUE_ORDSEQ_DRAIN = 0x02, /* waiting for the queue to be drained */
438 QUEUE_ORDSEQ_PREFLUSH = 0x04, /* pre-flushing in progress */
439 QUEUE_ORDSEQ_BAR = 0x08, /* original barrier req in progress */
440 QUEUE_ORDSEQ_POSTFLUSH = 0x10, /* post-flushing in progress */
441 QUEUE_ORDSEQ_DONE = 0x20,
442};
1da177e4
LT
443
444#define blk_queue_plugged(q) test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
445#define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
446#define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
797e7dbb 447#define blk_queue_flushing(q) ((q)->ordseq)
1da177e4 448
4aff5e23
JA
449#define blk_fs_request(rq) ((rq)->cmd_type == REQ_TYPE_FS)
450#define blk_pc_request(rq) ((rq)->cmd_type == REQ_TYPE_BLOCK_PC)
451#define blk_special_request(rq) ((rq)->cmd_type == REQ_TYPE_SPECIAL)
452#define blk_sense_request(rq) ((rq)->cmd_type == REQ_TYPE_SENSE)
453
454#define blk_noretry_request(rq) ((rq)->cmd_flags & REQ_FAILFAST)
455#define blk_rq_started(rq) ((rq)->cmd_flags & REQ_STARTED)
1da177e4
LT
456
457#define blk_account_rq(rq) (blk_rq_started(rq) && blk_fs_request(rq))
458
4aff5e23
JA
459#define blk_pm_suspend_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND)
460#define blk_pm_resume_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_RESUME)
1da177e4 461#define blk_pm_request(rq) \
4aff5e23 462 (blk_pm_suspend_request(rq) || blk_pm_resume_request(rq))
1da177e4 463
4aff5e23
JA
464#define blk_sorted_rq(rq) ((rq)->cmd_flags & REQ_SORTED)
465#define blk_barrier_rq(rq) ((rq)->cmd_flags & REQ_HARDBARRIER)
466#define blk_fua_rq(rq) ((rq)->cmd_flags & REQ_FUA)
abae1fde 467#define blk_bidi_rq(rq) ((rq)->next_rq != NULL)
bf2de6f5 468#define blk_empty_barrier(rq) (blk_barrier_rq(rq) && blk_fs_request(rq) && !(rq)->hard_nr_sectors)
336cdb40
KU
469/* rq->queuelist of dequeued request must be list_empty() */
470#define blk_queued_rq(rq) (!list_empty(&(rq)->queuelist))
1da177e4
LT
471
472#define list_entry_rq(ptr) list_entry((ptr), struct request, queuelist)
473
4aff5e23 474#define rq_data_dir(rq) ((rq)->cmd_flags & 1)
1da177e4 475
9e2585a8
JA
476/*
477 * We regard a request as sync, if it's a READ or a SYNC write.
478 */
479#define rq_is_sync(rq) (rq_data_dir((rq)) == READ || (rq)->cmd_flags & REQ_RW_SYNC)
5404bc7a 480#define rq_is_meta(rq) ((rq)->cmd_flags & REQ_RW_META)
9e2585a8 481
1da177e4
LT
482static inline int blk_queue_full(struct request_queue *q, int rw)
483{
484 if (rw == READ)
485 return test_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
486 return test_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
487}
488
489static inline void blk_set_queue_full(struct request_queue *q, int rw)
490{
491 if (rw == READ)
492 set_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
493 else
494 set_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
495}
496
497static inline void blk_clear_queue_full(struct request_queue *q, int rw)
498{
499 if (rw == READ)
500 clear_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
501 else
502 clear_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
503}
504
505
506/*
507 * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
508 * it already be started by driver.
509 */
510#define RQ_NOMERGE_FLAGS \
511 (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER)
512#define rq_mergeable(rq) \
4aff5e23 513 (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && blk_fs_request((rq)))
1da177e4 514
1da177e4
LT
515/*
516 * q->prep_rq_fn return values
517 */
518#define BLKPREP_OK 0 /* serve it */
519#define BLKPREP_KILL 1 /* fatal error, kill */
520#define BLKPREP_DEFER 2 /* leave on queue */
521
522extern unsigned long blk_max_low_pfn, blk_max_pfn;
523
524/*
525 * standard bounce addresses:
526 *
527 * BLK_BOUNCE_HIGH : bounce all highmem pages
528 * BLK_BOUNCE_ANY : don't bounce anything
529 * BLK_BOUNCE_ISA : bounce pages above ISA DMA boundary
530 */
531#define BLK_BOUNCE_HIGH ((u64)blk_max_low_pfn << PAGE_SHIFT)
532#define BLK_BOUNCE_ANY ((u64)blk_max_pfn << PAGE_SHIFT)
533#define BLK_BOUNCE_ISA (ISA_DMA_THRESHOLD)
534
3d6392cf
JA
535/*
536 * default timeout for SG_IO if none specified
537 */
538#define BLK_DEFAULT_SG_TIMEOUT (60 * HZ)
539
2a7326b5 540#ifdef CONFIG_BOUNCE
1da177e4 541extern int init_emergency_isa_pool(void);
165125e1 542extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
1da177e4
LT
543#else
544static inline int init_emergency_isa_pool(void)
545{
546 return 0;
547}
165125e1 548static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
1da177e4
LT
549{
550}
551#endif /* CONFIG_MMU */
552
5705f702
N
553struct req_iterator {
554 int i;
555 struct bio *bio;
556};
557
558/* This should not be used directly - use rq_for_each_segment */
559#define __rq_for_each_bio(_bio, rq) \
1da177e4
LT
560 if ((rq->bio)) \
561 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
562
5705f702
N
563#define rq_for_each_segment(bvl, _rq, _iter) \
564 __rq_for_each_bio(_iter.bio, _rq) \
565 bio_for_each_segment(bvl, _iter.bio, _iter.i)
566
567#define rq_iter_last(rq, _iter) \
568 (_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)
569
1da177e4
LT
570extern int blk_register_queue(struct gendisk *disk);
571extern void blk_unregister_queue(struct gendisk *disk);
572extern void register_disk(struct gendisk *dev);
573extern void generic_make_request(struct bio *bio);
574extern void blk_put_request(struct request *);
165125e1 575extern void __blk_put_request(struct request_queue *, struct request *);
8ffdc655 576extern void blk_end_sync_rq(struct request *rq, int error);
165125e1
JA
577extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
578extern void blk_insert_request(struct request_queue *, struct request *, int, void *);
579extern void blk_requeue_request(struct request_queue *, struct request *);
580extern void blk_plug_device(struct request_queue *);
581extern int blk_remove_plug(struct request_queue *);
582extern void blk_recount_segments(struct request_queue *, struct bio *);
45e79a3a
FT
583extern int scsi_cmd_ioctl(struct file *, struct request_queue *,
584 struct gendisk *, unsigned int, void __user *);
21b2f0c8
CH
585extern int sg_scsi_ioctl(struct file *, struct request_queue *,
586 struct gendisk *, struct scsi_ioctl_command __user *);
3fcfab16 587
1aa4f24f
JA
588/*
589 * Temporary export, until SCSI gets fixed up.
590 */
3001ca77
N
591extern int blk_rq_append_bio(struct request_queue *q, struct request *rq,
592 struct bio *bio);
1aa4f24f 593
3fcfab16
AM
594/*
595 * A queue has just exitted congestion. Note this in the global counter of
596 * congested queues, and wake up anyone who was waiting for requests to be
597 * put back.
598 */
165125e1 599static inline void blk_clear_queue_congested(struct request_queue *q, int rw)
3fcfab16
AM
600{
601 clear_bdi_congested(&q->backing_dev_info, rw);
602}
603
604/*
605 * A queue has just entered congestion. Flag that in the queue's VM-visible
606 * state flags and increment the global gounter of congested queues.
607 */
165125e1 608static inline void blk_set_queue_congested(struct request_queue *q, int rw)
3fcfab16
AM
609{
610 set_bdi_congested(&q->backing_dev_info, rw);
611}
612
165125e1
JA
613extern void blk_start_queue(struct request_queue *q);
614extern void blk_stop_queue(struct request_queue *q);
1da177e4 615extern void blk_sync_queue(struct request_queue *q);
165125e1
JA
616extern void __blk_stop_queue(struct request_queue *q);
617extern void blk_run_queue(struct request_queue *);
618extern void blk_start_queueing(struct request_queue *);
619extern int blk_rq_map_user(struct request_queue *, struct request *, void __user *, unsigned long);
8e5cfc45 620extern int blk_rq_unmap_user(struct bio *);
165125e1
JA
621extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
622extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
0e75f906 623 struct sg_iovec *, int, unsigned int);
165125e1 624extern int blk_execute_rq(struct request_queue *, struct gendisk *,
994ca9a1 625 struct request *, int);
165125e1 626extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
15fc858a 627 struct request *, int, rq_end_io_fn *);
337ad41d 628extern int blk_verify_command(unsigned char *, int);
2ad8b1ef 629extern void blk_unplug(struct request_queue *q);
6e39b69e 630
165125e1 631static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
1da177e4
LT
632{
633 return bdev->bd_disk->queue;
634}
635
636static inline void blk_run_backing_dev(struct backing_dev_info *bdi,
637 struct page *page)
638{
639 if (bdi && bdi->unplug_io_fn)
640 bdi->unplug_io_fn(bdi, page);
641}
642
643static inline void blk_run_address_space(struct address_space *mapping)
644{
645 if (mapping)
646 blk_run_backing_dev(mapping->backing_dev_info, NULL);
647}
648
649/*
3bcddeac
KU
650 * blk_end_request() and friends.
651 * __blk_end_request() and end_request() must be called with
652 * the request queue spinlock acquired.
1da177e4
LT
653 *
654 * Several drivers define their own end_request and call
3bcddeac
KU
655 * blk_end_request() for parts of the original function.
656 * This prevents code duplication in drivers.
1da177e4 657 */
336cdb40
KU
658extern int blk_end_request(struct request *rq, int error, int nr_bytes);
659extern int __blk_end_request(struct request *rq, int error, int nr_bytes);
e3a04fe3
KU
660extern int blk_end_bidi_request(struct request *rq, int error, int nr_bytes,
661 int bidi_bytes);
a0cd1285
JA
662extern void end_request(struct request *, int);
663extern void end_queued_request(struct request *, int);
664extern void end_dequeued_request(struct request *, int);
e19a3ab0
KU
665extern int blk_end_request_callback(struct request *rq, int error, int nr_bytes,
666 int (drv_callback)(struct request *));
ff856bad
JA
667extern void blk_complete_request(struct request *);
668
1da177e4 669/*
3b11313a
KU
670 * blk_end_request() takes bytes instead of sectors as a complete size.
671 * blk_rq_bytes() returns bytes left to complete in the entire request.
672 * blk_rq_cur_bytes() returns bytes left to complete in the current segment.
1da177e4 673 */
3b11313a
KU
674extern unsigned int blk_rq_bytes(struct request *rq);
675extern unsigned int blk_rq_cur_bytes(struct request *rq);
1da177e4
LT
676
677static inline void blkdev_dequeue_request(struct request *req)
678{
8922e16c 679 elv_dequeue_request(req->q, req);
1da177e4 680}
1da177e4 681
1da177e4
LT
682/*
683 * Access functions for manipulating queue properties
684 */
165125e1 685extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
1946089a 686 spinlock_t *lock, int node_id);
165125e1
JA
687extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
688extern void blk_cleanup_queue(struct request_queue *);
689extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
690extern void blk_queue_bounce_limit(struct request_queue *, u64);
691extern void blk_queue_max_sectors(struct request_queue *, unsigned int);
692extern void blk_queue_max_phys_segments(struct request_queue *, unsigned short);
693extern void blk_queue_max_hw_segments(struct request_queue *, unsigned short);
694extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
695extern void blk_queue_hardsect_size(struct request_queue *, unsigned short);
696extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
fa0ccd83
JB
697extern int blk_queue_dma_drain(struct request_queue *q, void *buf,
698 unsigned int size);
165125e1
JA
699extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
700extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
701extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
702extern void blk_queue_dma_alignment(struct request_queue *, int);
11c3e689 703extern void blk_queue_update_dma_alignment(struct request_queue *, int);
165125e1 704extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
1da177e4 705extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
165125e1 706extern int blk_queue_ordered(struct request_queue *, unsigned, prepare_flush_fn *);
165125e1
JA
707extern int blk_do_ordered(struct request_queue *, struct request **);
708extern unsigned blk_ordered_cur_seq(struct request_queue *);
797e7dbb 709extern unsigned blk_ordered_req_seq(struct request *);
165125e1 710extern void blk_ordered_complete_seq(struct request_queue *, unsigned, int);
1da177e4 711
165125e1 712extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
1da177e4 713extern void blk_dump_rq_flags(struct request *, char *);
165125e1
JA
714extern void generic_unplug_device(struct request_queue *);
715extern void __generic_unplug_device(struct request_queue *);
1da177e4 716extern long nr_blockdev_pages(void);
1da177e4 717
165125e1
JA
718int blk_get_queue(struct request_queue *);
719struct request_queue *blk_alloc_queue(gfp_t);
720struct request_queue *blk_alloc_queue_node(gfp_t, int);
721extern void blk_put_queue(struct request_queue *);
1da177e4
LT
722
723/*
724 * tag stuff
725 */
726#define blk_queue_tag_depth(q) ((q)->queue_tags->busy)
727#define blk_queue_tag_queue(q) ((q)->queue_tags->busy < (q)->queue_tags->max_depth)
4aff5e23 728#define blk_rq_tagged(rq) ((rq)->cmd_flags & REQ_QUEUED)
165125e1
JA
729extern int blk_queue_start_tag(struct request_queue *, struct request *);
730extern struct request *blk_queue_find_tag(struct request_queue *, int);
731extern void blk_queue_end_tag(struct request_queue *, struct request *);
732extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *);
733extern void blk_queue_free_tags(struct request_queue *);
734extern int blk_queue_resize_tags(struct request_queue *, int);
735extern void blk_queue_invalidate_tags(struct request_queue *);
492dfb48
JB
736extern struct blk_queue_tag *blk_init_tags(int);
737extern void blk_free_tags(struct blk_queue_tag *);
1da177e4 738
f583f492
DS
739static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
740 int tag)
741{
742 if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
743 return NULL;
744 return bqt->tag_index[tag];
745}
746
1da177e4
LT
747extern int blkdev_issue_flush(struct block_device *, sector_t *);
748
749#define MAX_PHYS_SEGMENTS 128
750#define MAX_HW_SEGMENTS 128
defd94b7
MC
751#define SAFE_MAX_SECTORS 255
752#define BLK_DEF_MAX_SECTORS 1024
1da177e4
LT
753
754#define MAX_SEGMENT_SIZE 65536
755
756#define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
757
165125e1 758static inline int queue_hardsect_size(struct request_queue *q)
1da177e4
LT
759{
760 int retval = 512;
761
762 if (q && q->hardsect_size)
763 retval = q->hardsect_size;
764
765 return retval;
766}
767
768static inline int bdev_hardsect_size(struct block_device *bdev)
769{
770 return queue_hardsect_size(bdev_get_queue(bdev));
771}
772
165125e1 773static inline int queue_dma_alignment(struct request_queue *q)
1da177e4 774{
482eb689 775 return q ? q->dma_alignment : 511;
1da177e4
LT
776}
777
1da177e4
LT
778/* assumes size > 256 */
779static inline unsigned int blksize_bits(unsigned int size)
780{
781 unsigned int bits = 8;
782 do {
783 bits++;
784 size >>= 1;
785 } while (size > 256);
786 return bits;
787}
788
2befb9e3 789static inline unsigned int block_size(struct block_device *bdev)
1da177e4
LT
790{
791 return bdev->bd_block_size;
792}
793
794typedef struct {struct page *v;} Sector;
795
796unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
797
798static inline void put_dev_sector(Sector p)
799{
800 page_cache_release(p.v);
801}
802
803struct work_struct;
804int kblockd_schedule_work(struct work_struct *work);
19a75d83 805void kblockd_flush_work(struct work_struct *work);
1da177e4 806
1da177e4
LT
807#define MODULE_ALIAS_BLOCKDEV(major,minor) \
808 MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
809#define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
810 MODULE_ALIAS("block-major-" __stringify(major) "-*")
811
812
9361401e
DH
813#else /* CONFIG_BLOCK */
814/*
815 * stubs for when the block layer is configured out
816 */
817#define buffer_heads_over_limit 0
818
9361401e
DH
819static inline long nr_blockdev_pages(void)
820{
821 return 0;
822}
823
bcfd8d36
AM
824static inline void exit_io_context(void)
825{
826}
9361401e 827
fd0928df
JA
828static inline int put_io_context(struct io_context *ioc)
829{
830 return 1;
831}
832
833
9361401e
DH
834#endif /* CONFIG_BLOCK */
835
1da177e4 836#endif