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[BLOCK] ll_rw_blk: Enable out-of-order request completions through softirq
[linux-2.6-block.git] / include / linux / blkdev.h
CommitLineData
1da177e4
LT		 1#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 {
1da177e4
LT		 57 /*
58 * circular list of cfq_io_contexts belonging to a process io context
59 */
60 struct list_head list;
61 struct cfq_queue *cfqq;
22e2c507
JA		 62 void *key;
63
64 struct io_context *ioc;
65
66 unsigned long last_end_request;
67 unsigned long last_queue;
68 unsigned long ttime_total;
69 unsigned long ttime_samples;
70 unsigned long ttime_mean;
71
72 void (*dtor)(struct cfq_io_context *);
73 void (*exit)(struct cfq_io_context *);
1da177e4
LT		 74};
75
76/*
77 * This is the per-process I/O subsystem state. It is refcounted and
78 * kmalloc'ed. Currently all fields are modified in process io context
79 * (apart from the atomic refcount), so require no locking.
80 */
81struct io_context {
82 atomic_t refcount;
22e2c507
JA		 83 struct task_struct *task;
84
85 int (*set_ioprio)(struct io_context *, unsigned int);
1da177e4
LT		 86
87 /*
88 * For request batching
89 */
90 unsigned long last_waited; /* Time last woken after wait for request */
91 int nr_batch_requests; /* Number of requests left in the batch */
92
1da177e4
LT		 93 struct as_io_context *aic;
94 struct cfq_io_context *cic;
95};
96
97void put_io_context(struct io_context *ioc);
98void exit_io_context(void);
8267e268
AV		 99struct io_context *current_io_context(gfp_t gfp_flags);
100struct io_context *get_io_context(gfp_t gfp_flags);
1da177e4
LT		 101void copy_io_context(struct io_context **pdst, struct io_context **psrc);
102void swap_io_context(struct io_context **ioc1, struct io_context **ioc2);
103
104struct request;
8ffdc655 105typedef void (rq_end_io_fn)(struct request *, int);
1da177e4
LT		 106
107struct request_list {
108 int count[2];
109 int starved[2];
cb98fc8b 110 int elvpriv;
1da177e4
LT		 111 mempool_t *rq_pool;
112 wait_queue_head_t wait[2];
1da177e4
LT		 113};
114
115#define BLK_MAX_CDB 16
116
117/*
118 * try to put the fields that are referenced together in the same cacheline
119 */
120struct request {
ff856bad
JA		 121 struct list_head queuelist;
122 struct list_head donelist;
123
1da177e4
LT		 124 unsigned long flags; /* see REQ_ bits below */
125
126 /* Maintain bio traversal state for part by part I/O submission.
127 * hard_* are block layer internals, no driver should touch them!
128 */
129
130 sector_t sector; /* next sector to submit */
131 unsigned long nr_sectors; /* no. of sectors left to submit */
132 /* no. of sectors left to submit in the current segment */
133 unsigned int current_nr_sectors;
134
135 sector_t hard_sector; /* next sector to complete */
136 unsigned long hard_nr_sectors; /* no. of sectors left to complete */
137 /* no. of sectors left to complete in the current segment */
138 unsigned int hard_cur_sectors;
139
140 struct bio *bio;
141 struct bio *biotail;
142
143 void *elevator_private;
ff856bad 144 void *completion_data;
1da177e4 145
22e2c507
JA		 146 unsigned short ioprio;
147
1da177e4
LT		 148 int rq_status; /* should split this into a few status bits */
149 struct gendisk *rq_disk;
150 int errors;
151 unsigned long start_time;
152
153 /* Number of scatter-gather DMA addr+len pairs after
154 * physical address coalescing is performed.
155 */
156 unsigned short nr_phys_segments;
157
158 /* Number of scatter-gather addr+len pairs after
159 * physical and DMA remapping hardware coalescing is performed.
160 * This is the number of scatter-gather entries the driver
161 * will actually have to deal with after DMA mapping is done.
162 */
163 unsigned short nr_hw_segments;
164
165 int tag;
166 char *buffer;
167
168 int ref_count;
169 request_queue_t *q;
170 struct request_list *rl;
171
172 struct completion *waiting;
173 void *special;
174
175 /*
176 * when request is used as a packet command carrier
177 */
178 unsigned int cmd_len;
179 unsigned char cmd[BLK_MAX_CDB];
180
181 unsigned int data_len;
182 void *data;
183
184 unsigned int sense_len;
185 void *sense;
186
187 unsigned int timeout;
17e01f21 188 int retries;
1da177e4
LT		 189
190 /*
191 * For Power Management requests
192 */
193 struct request_pm_state *pm;
194
195 /*
196 * completion callback. end_io_data should be folded in with waiting
197 */
198 rq_end_io_fn *end_io;
199 void *end_io_data;
200};
201
202/*
203 * first three bits match BIO_RW* bits, important
204 */
205enum rq_flag_bits {
206 __REQ_RW, /* not set, read. set, write */
207 __REQ_FAILFAST, /* no low level driver retries */
8922e16c 208 __REQ_SORTED, /* elevator knows about this request */
1da177e4
LT		 209 __REQ_SOFTBARRIER, /* may not be passed by ioscheduler */
210 __REQ_HARDBARRIER, /* may not be passed by drive either */
797e7dbb 211 __REQ_FUA, /* forced unit access */
1da177e4
LT		 212 __REQ_CMD, /* is a regular fs rw request */
213 __REQ_NOMERGE, /* don't touch this for merging */
214 __REQ_STARTED, /* drive already may have started this one */
215 __REQ_DONTPREP, /* don't call prep for this one */
216 __REQ_QUEUED, /* uses queueing */
cb98fc8b 217 __REQ_ELVPRIV, /* elevator private data attached */
1da177e4
LT		 218 /*
219 * for ATA/ATAPI devices
220 */
221 __REQ_PC, /* packet command (special) */
222 __REQ_BLOCK_PC, /* queued down pc from block layer */
223 __REQ_SENSE, /* sense retrival */
224
225 __REQ_FAILED, /* set if the request failed */
226 __REQ_QUIET, /* don't worry about errors */
227 __REQ_SPECIAL, /* driver suplied command */
228 __REQ_DRIVE_CMD,
229 __REQ_DRIVE_TASK,
230 __REQ_DRIVE_TASKFILE,
231 __REQ_PREEMPT, /* set for "ide_preempt" requests */
232 __REQ_PM_SUSPEND, /* suspend request */
233 __REQ_PM_RESUME, /* resume request */
234 __REQ_PM_SHUTDOWN, /* shutdown request */
797e7dbb 235 __REQ_ORDERED_COLOR, /* is before or after barrier */
1da177e4
LT		 236 __REQ_NR_BITS, /* stops here */
237};
238
239#define REQ_RW (1 << __REQ_RW)
240#define REQ_FAILFAST (1 << __REQ_FAILFAST)
8922e16c 241#define REQ_SORTED (1 << __REQ_SORTED)
1da177e4
LT		 242#define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER)
243#define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER)
797e7dbb 244#define REQ_FUA (1 << __REQ_FUA)
1da177e4
LT		 245#define REQ_CMD (1 << __REQ_CMD)
246#define REQ_NOMERGE (1 << __REQ_NOMERGE)
247#define REQ_STARTED (1 << __REQ_STARTED)
248#define REQ_DONTPREP (1 << __REQ_DONTPREP)
249#define REQ_QUEUED (1 << __REQ_QUEUED)
cb98fc8b 250#define REQ_ELVPRIV (1 << __REQ_ELVPRIV)
1da177e4
LT		 251#define REQ_PC (1 << __REQ_PC)
252#define REQ_BLOCK_PC (1 << __REQ_BLOCK_PC)
253#define REQ_SENSE (1 << __REQ_SENSE)
254#define REQ_FAILED (1 << __REQ_FAILED)
255#define REQ_QUIET (1 << __REQ_QUIET)
256#define REQ_SPECIAL (1 << __REQ_SPECIAL)
257#define REQ_DRIVE_CMD (1 << __REQ_DRIVE_CMD)
258#define REQ_DRIVE_TASK (1 << __REQ_DRIVE_TASK)
259#define REQ_DRIVE_TASKFILE (1 << __REQ_DRIVE_TASKFILE)
260#define REQ_PREEMPT (1 << __REQ_PREEMPT)
261#define REQ_PM_SUSPEND (1 << __REQ_PM_SUSPEND)
262#define REQ_PM_RESUME (1 << __REQ_PM_RESUME)
263#define REQ_PM_SHUTDOWN (1 << __REQ_PM_SHUTDOWN)
797e7dbb 264#define REQ_ORDERED_COLOR (1 << __REQ_ORDERED_COLOR)
1da177e4
LT		 265
266/*
267 * State information carried for REQ_PM_SUSPEND and REQ_PM_RESUME
268 * requests. Some step values could eventually be made generic.
269 */
270struct request_pm_state
271{
272 /* PM state machine step value, currently driver specific */
273 int pm_step;
274 /* requested PM state value (S1, S2, S3, S4, ...) */
275 u32 pm_state;
276 void* data; /* for driver use */
277};
278
279#include <linux/elevator.h>
280
281typedef int (merge_request_fn) (request_queue_t *, struct request *,
282 struct bio *);
283typedef int (merge_requests_fn) (request_queue_t *, struct request *,
284 struct request *);
285typedef void (request_fn_proc) (request_queue_t *q);
286typedef int (make_request_fn) (request_queue_t *q, struct bio *bio);
287typedef int (prep_rq_fn) (request_queue_t *, struct request *);
288typedef void (unplug_fn) (request_queue_t *);
289
290struct bio_vec;
291typedef int (merge_bvec_fn) (request_queue_t *, struct bio *, struct bio_vec *);
292typedef void (activity_fn) (void *data, int rw);
293typedef int (issue_flush_fn) (request_queue_t *, struct gendisk *, sector_t *);
797e7dbb 294typedef void (prepare_flush_fn) (request_queue_t *, struct request *);
ff856bad 295typedef void (softirq_done_fn)(struct request *);
1da177e4
LT		 296
297enum blk_queue_state {
298 Queue_down,
299 Queue_up,
300};
301
1da177e4
LT		 302struct blk_queue_tag {
303 struct request **tag_index; /* map of busy tags */
304 unsigned long *tag_map; /* bit map of free/busy tags */
305 struct list_head busy_list; /* fifo list of busy tags */
306 int busy; /* current depth */
307 int max_depth; /* what we will send to device */
ba025082 308 int real_max_depth; /* what the array can hold */
1da177e4
LT		 309 atomic_t refcnt; /* map can be shared */
310};
311
312struct request_queue
313{
314 /*
315 * Together with queue_head for cacheline sharing
316 */
317 struct list_head queue_head;
318 struct request *last_merge;
319 elevator_t *elevator;
320
321 /*
322 * the queue request freelist, one for reads and one for writes
323 */
324 struct request_list rq;
325
326 request_fn_proc *request_fn;
327 merge_request_fn *back_merge_fn;
328 merge_request_fn *front_merge_fn;
329 merge_requests_fn *merge_requests_fn;
330 make_request_fn *make_request_fn;
331 prep_rq_fn *prep_rq_fn;
332 unplug_fn *unplug_fn;
333 merge_bvec_fn *merge_bvec_fn;
334 activity_fn *activity_fn;
335 issue_flush_fn *issue_flush_fn;
336 prepare_flush_fn *prepare_flush_fn;
ff856bad 337 softirq_done_fn *softirq_done_fn;
1da177e4 338
8922e16c
TH		 339 /*
340 * Dispatch queue sorting
341 */
1b47f531 342 sector_t end_sector;
8922e16c 343 struct request *boundary_rq;
8922e16c 344
1da177e4
LT		 345 /*
346 * Auto-unplugging state
347 */
348 struct timer_list unplug_timer;
349 int unplug_thresh; /* After this many requests */
350 unsigned long unplug_delay; /* After this many jiffies */
351 struct work_struct unplug_work;
352
353 struct backing_dev_info backing_dev_info;
354
355 /*
356 * The queue owner gets to use this for whatever they like.
357 * ll_rw_blk doesn't touch it.
358 */
359 void *queuedata;
360
361 void *activity_data;
362
363 /*
364 * queue needs bounce pages for pages above this limit
365 */
366 unsigned long bounce_pfn;
8267e268 367 gfp_t bounce_gfp;
1da177e4
LT		 368
369 /*
370 * various queue flags, see QUEUE_* below
371 */
372 unsigned long queue_flags;
373
374 /*
152587de 375 * protects queue structures from reentrancy. ->__queue_lock should
376 * _never_ be used directly, it is queue private. always use
377 * ->queue_lock.
1da177e4 378 */
152587de 379 spinlock_t __queue_lock;
1da177e4
LT		 380 spinlock_t *queue_lock;
381
382 /*
383 * queue kobject
384 */
385 struct kobject kobj;
386
387 /*
388 * queue settings
389 */
390 unsigned long nr_requests; /* Max # of requests */
391 unsigned int nr_congestion_on;
392 unsigned int nr_congestion_off;
393 unsigned int nr_batching;
394
395 unsigned short max_sectors;
396 unsigned short max_hw_sectors;
397 unsigned short max_phys_segments;
398 unsigned short max_hw_segments;
399 unsigned short hardsect_size;
400 unsigned int max_segment_size;
401
402 unsigned long seg_boundary_mask;
403 unsigned int dma_alignment;
404
405 struct blk_queue_tag *queue_tags;
406
407 atomic_t refcnt;
408
15853af9 409 unsigned int nr_sorted;
1da177e4
LT		 410 unsigned int in_flight;
411
412 /*
413 * sg stuff
414 */
415 unsigned int sg_timeout;
416 unsigned int sg_reserved_size;
1946089a 417 int node;
1da177e4 418
1da177e4
LT		 419 /*
420 * reserved for flush operations
421 */
797e7dbb
TH		 422 unsigned int ordered, next_ordered, ordseq;
423 int orderr, ordcolor;
424 struct request pre_flush_rq, bar_rq, post_flush_rq;
425 struct request *orig_bar_rq;
426 unsigned int bi_size;
1da177e4
LT		 427};
428
429#define RQ_INACTIVE (-1)
430#define RQ_ACTIVE 1
431#define RQ_SCSI_BUSY 0xffff
432#define RQ_SCSI_DONE 0xfffe
433#define RQ_SCSI_DISCONNECTING 0xffe0
434
435#define QUEUE_FLAG_CLUSTER 0 /* cluster several segments into 1 */
436#define QUEUE_FLAG_QUEUED 1 /* uses generic tag queueing */
437#define QUEUE_FLAG_STOPPED 2 /* queue is stopped */
438#define QUEUE_FLAG_READFULL 3 /* write queue has been filled */
439#define QUEUE_FLAG_WRITEFULL 4 /* read queue has been filled */
440#define QUEUE_FLAG_DEAD 5 /* queue being torn down */
441#define QUEUE_FLAG_REENTER 6 /* Re-entrancy avoidance */
442#define QUEUE_FLAG_PLUGGED 7 /* queue is plugged */
64521d1a 443#define QUEUE_FLAG_ELVSWITCH 8 /* don't use elevator, just do FIFO */
797e7dbb
TH		 444
445enum {
446 /*
447 * Hardbarrier is supported with one of the following methods.
448 *
449 * NONE : hardbarrier unsupported
450 * DRAIN : ordering by draining is enough
451 * DRAIN_FLUSH : ordering by draining w/ pre and post flushes
452 * DRAIN_FUA : ordering by draining w/ pre flush and FUA write
453 * TAG : ordering by tag is enough
454 * TAG_FLUSH : ordering by tag w/ pre and post flushes
455 * TAG_FUA : ordering by tag w/ pre flush and FUA write
456 */
457 QUEUE_ORDERED_NONE = 0x00,
458 QUEUE_ORDERED_DRAIN = 0x01,
459 QUEUE_ORDERED_TAG = 0x02,
460
461 QUEUE_ORDERED_PREFLUSH = 0x10,
462 QUEUE_ORDERED_POSTFLUSH = 0x20,
463 QUEUE_ORDERED_FUA = 0x40,
464
465 QUEUE_ORDERED_DRAIN_FLUSH = QUEUE_ORDERED_DRAIN |
466 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
467 QUEUE_ORDERED_DRAIN_FUA = QUEUE_ORDERED_DRAIN |
468 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
469 QUEUE_ORDERED_TAG_FLUSH = QUEUE_ORDERED_TAG |
470 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
471 QUEUE_ORDERED_TAG_FUA = QUEUE_ORDERED_TAG |
472 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
473
474 /*
475 * Ordered operation sequence
476 */
477 QUEUE_ORDSEQ_STARTED = 0x01, /* flushing in progress */
478 QUEUE_ORDSEQ_DRAIN = 0x02, /* waiting for the queue to be drained */
479 QUEUE_ORDSEQ_PREFLUSH = 0x04, /* pre-flushing in progress */
480 QUEUE_ORDSEQ_BAR = 0x08, /* original barrier req in progress */
481 QUEUE_ORDSEQ_POSTFLUSH = 0x10, /* post-flushing in progress */
482 QUEUE_ORDSEQ_DONE = 0x20,
483};
1da177e4
LT		 484
485#define blk_queue_plugged(q) test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
486#define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
487#define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
797e7dbb 488#define blk_queue_flushing(q) ((q)->ordseq)
1da177e4
LT		 489
490#define blk_fs_request(rq) ((rq)->flags & REQ_CMD)
491#define blk_pc_request(rq) ((rq)->flags & REQ_BLOCK_PC)
492#define blk_noretry_request(rq) ((rq)->flags & REQ_FAILFAST)
493#define blk_rq_started(rq) ((rq)->flags & REQ_STARTED)
494
495#define blk_account_rq(rq) (blk_rq_started(rq) && blk_fs_request(rq))
496
497#define blk_pm_suspend_request(rq) ((rq)->flags & REQ_PM_SUSPEND)
498#define blk_pm_resume_request(rq) ((rq)->flags & REQ_PM_RESUME)
499#define blk_pm_request(rq) \
500 ((rq)->flags & (REQ_PM_SUSPEND | REQ_PM_RESUME))
501
8922e16c 502#define blk_sorted_rq(rq) ((rq)->flags & REQ_SORTED)
1da177e4 503#define blk_barrier_rq(rq) ((rq)->flags & REQ_HARDBARRIER)
797e7dbb 504#define blk_fua_rq(rq) ((rq)->flags & REQ_FUA)
1da177e4
LT		 505
506#define list_entry_rq(ptr) list_entry((ptr), struct request, queuelist)
507
508#define rq_data_dir(rq) ((rq)->flags & 1)
509
510static inline int blk_queue_full(struct request_queue *q, int rw)
511{
512 if (rw == READ)
513 return test_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
514 return test_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
515}
516
517static inline void blk_set_queue_full(struct request_queue *q, int rw)
518{
519 if (rw == READ)
520 set_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
521 else
522 set_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
523}
524
525static inline void blk_clear_queue_full(struct request_queue *q, int rw)
526{
527 if (rw == READ)
528 clear_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
529 else
530 clear_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
531}
532
533
534/*
535 * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
536 * it already be started by driver.
537 */
538#define RQ_NOMERGE_FLAGS \
539 (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER)
540#define rq_mergeable(rq) \
541 (!((rq)->flags & RQ_NOMERGE_FLAGS) && blk_fs_request((rq)))
542
543/*
544 * noop, requests are automagically marked as active/inactive by I/O
545 * scheduler -- see elv_next_request
546 */
547#define blk_queue_headactive(q, head_active)
548
549/*
550 * q->prep_rq_fn return values
551 */
552#define BLKPREP_OK 0 /* serve it */
553#define BLKPREP_KILL 1 /* fatal error, kill */
554#define BLKPREP_DEFER 2 /* leave on queue */
555
556extern unsigned long blk_max_low_pfn, blk_max_pfn;
557
558/*
559 * standard bounce addresses:
560 *
561 * BLK_BOUNCE_HIGH : bounce all highmem pages
562 * BLK_BOUNCE_ANY : don't bounce anything
563 * BLK_BOUNCE_ISA : bounce pages above ISA DMA boundary
564 */
565#define BLK_BOUNCE_HIGH ((u64)blk_max_low_pfn << PAGE_SHIFT)
566#define BLK_BOUNCE_ANY ((u64)blk_max_pfn << PAGE_SHIFT)
567#define BLK_BOUNCE_ISA (ISA_DMA_THRESHOLD)
568
569#ifdef CONFIG_MMU
570extern int init_emergency_isa_pool(void);
571extern void blk_queue_bounce(request_queue_t *q, struct bio **bio);
572#else
573static inline int init_emergency_isa_pool(void)
574{
575 return 0;
576}
577static inline void blk_queue_bounce(request_queue_t *q, struct bio **bio)
578{
579}
580#endif /* CONFIG_MMU */
581
582#define rq_for_each_bio(_bio, rq) \
583 if ((rq->bio)) \
584 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
585
586struct sec_size {
587 unsigned block_size;
588 unsigned block_size_bits;
589};
590
591extern int blk_register_queue(struct gendisk *disk);
592extern void blk_unregister_queue(struct gendisk *disk);
593extern void register_disk(struct gendisk *dev);
594extern void generic_make_request(struct bio *bio);
595extern void blk_put_request(struct request *);
6e39b69e 596extern void __blk_put_request(request_queue_t *, struct request *);
8ffdc655 597extern void blk_end_sync_rq(struct request *rq, int error);
1da177e4 598extern void blk_attempt_remerge(request_queue_t *, struct request *);
8267e268 599extern struct request *blk_get_request(request_queue_t *, int, gfp_t);
867d1191 600extern void blk_insert_request(request_queue_t *, struct request *, int, void *);
1da177e4
LT		 601extern void blk_requeue_request(request_queue_t *, struct request *);
602extern void blk_plug_device(request_queue_t *);
603extern int blk_remove_plug(request_queue_t *);
604extern void blk_recount_segments(request_queue_t *, struct bio *);
1da177e4
LT		 605extern int scsi_cmd_ioctl(struct file *, struct gendisk *, unsigned int, void __user *);
606extern void blk_start_queue(request_queue_t *q);
607extern void blk_stop_queue(request_queue_t *q);
608extern void blk_sync_queue(struct request_queue *q);
609extern void __blk_stop_queue(request_queue_t *q);
610extern void blk_run_queue(request_queue_t *);
611extern void blk_queue_activity_fn(request_queue_t *, activity_fn *, void *);
dd1cab95
JA		 612extern int blk_rq_map_user(request_queue_t *, struct request *, void __user *, unsigned int);
613extern int blk_rq_unmap_user(struct bio *, unsigned int);
8267e268 614extern int blk_rq_map_kern(request_queue_t *, struct request *, void *, unsigned int, gfp_t);
f1970baf 615extern int blk_rq_map_user_iov(request_queue_t *, struct request *, struct sg_iovec *, int);
994ca9a1
JB		 616extern int blk_execute_rq(request_queue_t *, struct gendisk *,
617 struct request *, int);
6e39b69e 618extern void blk_execute_rq_nowait(request_queue_t *, struct gendisk *,
15fc858a 619 struct request *, int, rq_end_io_fn *);
6e39b69e 620
1da177e4
LT		 621static inline request_queue_t *bdev_get_queue(struct block_device *bdev)
622{
623 return bdev->bd_disk->queue;
624}
625
626static inline void blk_run_backing_dev(struct backing_dev_info *bdi,
627 struct page *page)
628{
629 if (bdi && bdi->unplug_io_fn)
630 bdi->unplug_io_fn(bdi, page);
631}
632
633static inline void blk_run_address_space(struct address_space *mapping)
634{
635 if (mapping)
636 blk_run_backing_dev(mapping->backing_dev_info, NULL);
637}
638
639/*
640 * end_request() and friends. Must be called with the request queue spinlock
641 * acquired. All functions called within end_request() _must_be_ atomic.
642 *
643 * Several drivers define their own end_request and call
644 * end_that_request_first() and end_that_request_last()
645 * for parts of the original function. This prevents
646 * code duplication in drivers.
647 */
648extern int end_that_request_first(struct request *, int, int);
649extern int end_that_request_chunk(struct request *, int, int);
8ffdc655 650extern void end_that_request_last(struct request *, int);
1da177e4 651extern void end_request(struct request *req, int uptodate);
ff856bad
JA		 652extern void blk_complete_request(struct request *);
653
654static inline int rq_all_done(struct request *rq, unsigned int nr_bytes)
655{
656 if (blk_fs_request(rq))
657 return (nr_bytes >= (rq->hard_nr_sectors << 9));
658 else if (blk_pc_request(rq))
659 return nr_bytes >= rq->data_len;
660
661 return 0;
662}
1da177e4
LT		 663
664/*
665 * end_that_request_first/chunk() takes an uptodate argument. we account
666 * any value <= as an io error. 0 means -EIO for compatability reasons,
667 * any other < 0 value is the direct error type. An uptodate value of
668 * 1 indicates successful io completion
669 */
670#define end_io_error(uptodate) (unlikely((uptodate) <= 0))
671
672static inline void blkdev_dequeue_request(struct request *req)
673{
8922e16c 674 elv_dequeue_request(req->q, req);
1da177e4 675}
1da177e4 676
1b47f531
JA		 677/*
678 * This should be in elevator.h, but that requires pulling in rq and q
679 */
680static inline void elv_dispatch_add_tail(struct request_queue *q,
681 struct request *rq)
682{
06b86245
TH		 683 if (q->last_merge == rq)
684 q->last_merge = NULL;
15853af9 685 q->nr_sorted--;
1da177e4 686
1b47f531
JA		 687 q->end_sector = rq_end_sector(rq);
688 q->boundary_rq = rq;
689 list_add_tail(&rq->queuelist, &q->queue_head);
1da177e4
LT		 690}
691
692/*
693 * Access functions for manipulating queue properties
694 */
1946089a
CL		 695extern request_queue_t *blk_init_queue_node(request_fn_proc *rfn,
696 spinlock_t *lock, int node_id);
1da177e4
LT		 697extern request_queue_t *blk_init_queue(request_fn_proc *, spinlock_t *);
698extern void blk_cleanup_queue(request_queue_t *);
699extern void blk_queue_make_request(request_queue_t *, make_request_fn *);
700extern void blk_queue_bounce_limit(request_queue_t *, u64);
701extern void blk_queue_max_sectors(request_queue_t *, unsigned short);
702extern void blk_queue_max_phys_segments(request_queue_t *, unsigned short);
703extern void blk_queue_max_hw_segments(request_queue_t *, unsigned short);
704extern void blk_queue_max_segment_size(request_queue_t *, unsigned int);
705extern void blk_queue_hardsect_size(request_queue_t *, unsigned short);
706extern void blk_queue_stack_limits(request_queue_t *t, request_queue_t *b);
707extern void blk_queue_segment_boundary(request_queue_t *, unsigned long);
708extern void blk_queue_prep_rq(request_queue_t *, prep_rq_fn *pfn);
709extern void blk_queue_merge_bvec(request_queue_t *, merge_bvec_fn *);
710extern void blk_queue_dma_alignment(request_queue_t *, int);
ff856bad 711extern void blk_queue_softirq_done(request_queue_t *, softirq_done_fn *);
1da177e4 712extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
797e7dbb 713extern int blk_queue_ordered(request_queue_t *, unsigned, prepare_flush_fn *);
1da177e4 714extern void blk_queue_issue_flush_fn(request_queue_t *, issue_flush_fn *);
797e7dbb
TH		 715extern int blk_do_ordered(request_queue_t *, struct request **);
716extern unsigned blk_ordered_cur_seq(request_queue_t *);
717extern unsigned blk_ordered_req_seq(struct request *);
718extern void blk_ordered_complete_seq(request_queue_t *, unsigned, int);
1da177e4
LT		 719
720extern int blk_rq_map_sg(request_queue_t *, struct request *, struct scatterlist *);
721extern void blk_dump_rq_flags(struct request *, char *);
722extern void generic_unplug_device(request_queue_t *);
723extern void __generic_unplug_device(request_queue_t *);
724extern long nr_blockdev_pages(void);
1da177e4
LT		 725
726int blk_get_queue(request_queue_t *);
8267e268
AV		 727request_queue_t *blk_alloc_queue(gfp_t);
728request_queue_t *blk_alloc_queue_node(gfp_t, int);
1da177e4
LT		 729#define blk_put_queue(q) blk_cleanup_queue((q))
730
731/*
732 * tag stuff
733 */
734#define blk_queue_tag_depth(q) ((q)->queue_tags->busy)
735#define blk_queue_tag_queue(q) ((q)->queue_tags->busy < (q)->queue_tags->max_depth)
736#define blk_rq_tagged(rq) ((rq)->flags & REQ_QUEUED)
737extern int blk_queue_start_tag(request_queue_t *, struct request *);
738extern struct request *blk_queue_find_tag(request_queue_t *, int);
739extern void blk_queue_end_tag(request_queue_t *, struct request *);
740extern int blk_queue_init_tags(request_queue_t *, int, struct blk_queue_tag *);
741extern void blk_queue_free_tags(request_queue_t *);
742extern int blk_queue_resize_tags(request_queue_t *, int);
743extern void blk_queue_invalidate_tags(request_queue_t *);
744extern long blk_congestion_wait(int rw, long timeout);
745
746extern void blk_rq_bio_prep(request_queue_t *, struct request *, struct bio *);
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
1da177e4
LT		 758static inline int queue_hardsect_size(request_queue_t *q)
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
773static inline int queue_dma_alignment(request_queue_t *q)
774{
775 int retval = 511;
776
777 if (q && q->dma_alignment)
778 retval = q->dma_alignment;
779
780 return retval;
781}
782
783static inline int bdev_dma_aligment(struct block_device *bdev)
784{
785 return queue_dma_alignment(bdev_get_queue(bdev));
786}
787
788#define blk_finished_io(nsects) do { } while (0)
789#define blk_started_io(nsects) do { } while (0)
790
791/* assumes size > 256 */
792static inline unsigned int blksize_bits(unsigned int size)
793{
794 unsigned int bits = 8;
795 do {
796 bits++;
797 size >>= 1;
798 } while (size > 256);
799 return bits;
800}
801
2befb9e3 802static inline unsigned int block_size(struct block_device *bdev)
1da177e4
LT		 803{
804 return bdev->bd_block_size;
805}
806
807typedef struct {struct page *v;} Sector;
808
809unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
810
811static inline void put_dev_sector(Sector p)
812{
813 page_cache_release(p.v);
814}
815
816struct work_struct;
817int kblockd_schedule_work(struct work_struct *work);
818void kblockd_flush(void);
819
820#ifdef CONFIG_LBD
821# include <asm/div64.h>
822# define sector_div(a, b) do_div(a, b)
823#else
824# define sector_div(n, b)( \
825{ \
826 int _res; \
827 _res = (n) % (b); \
828 (n) /= (b); \
829 _res; \
830} \
831)
832#endif
833
834#define MODULE_ALIAS_BLOCKDEV(major,minor) \
835 MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
836#define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
837 MODULE_ALIAS("block-major-" __stringify(major) "-*")
838
839
840#endif
Linux 6.x block layer and io_uring tree(s)