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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#ifndef _LINUX_BLKDEV_H
2#define _LINUX_BLKDEV_H
3
Linus Torvalds1da177e2005-04-16 15:20:36 -07004#include <linux/major.h>
5#include <linux/genhd.h>
6#include <linux/list.h>
7#include <linux/timer.h>
8#include <linux/workqueue.h>
9#include <linux/pagemap.h>
10#include <linux/backing-dev.h>
11#include <linux/wait.h>
12#include <linux/mempool.h>
13#include <linux/bio.h>
14#include <linux/module.h>
15#include <linux/stringify.h>
16
17#include <asm/scatterlist.h>
18
Christoph Hellwig21b2f0c2006-03-22 17:52:04 +010019struct scsi_ioctl_command;
20
Linus Torvalds1da177e2005-04-16 15:20:36 -070021struct request_queue;
22typedef struct request_queue request_queue_t;
23struct elevator_queue;
24typedef struct elevator_queue elevator_t;
25struct request_pm_state;
Jens Axboe2056a782006-03-23 20:00:26 +010026struct blk_trace;
Linus Torvalds1da177e2005-04-16 15:20:36 -070027
28#define BLKDEV_MIN_RQ 4
29#define BLKDEV_MAX_RQ 128 /* Default maximum */
30
31/*
32 * This is the per-process anticipatory I/O scheduler state.
33 */
34struct as_io_context {
35 spinlock_t lock;
36
37 void (*dtor)(struct as_io_context *aic); /* destructor */
38 void (*exit)(struct as_io_context *aic); /* called on task exit */
39
40 unsigned long state;
41 atomic_t nr_queued; /* queued reads & sync writes */
42 atomic_t nr_dispatched; /* number of requests gone to the drivers */
43
44 /* IO History tracking */
45 /* Thinktime */
46 unsigned long last_end_request;
47 unsigned long ttime_total;
48 unsigned long ttime_samples;
49 unsigned long ttime_mean;
50 /* Layout pattern */
51 unsigned int seek_samples;
52 sector_t last_request_pos;
53 u64 seek_total;
54 sector_t seek_mean;
55};
56
57struct cfq_queue;
58struct cfq_io_context {
Jens Axboee2d74ac2006-03-28 08:59:01 +020059 struct rb_node rb_node;
Jens Axboe22e2c502005-06-27 10:55:12 +020060 void *key;
61
Jens Axboee2d74ac2006-03-28 08:59:01 +020062 struct cfq_queue *cfqq[2];
63
Jens Axboe22e2c502005-06-27 10:55:12 +020064 struct io_context *ioc;
65
66 unsigned long last_end_request;
Jens Axboe206dc692006-03-28 13:03:44 +020067 sector_t last_request_pos;
68 unsigned long last_queue;
69
Jens Axboe22e2c502005-06-27 10:55:12 +020070 unsigned long ttime_total;
71 unsigned long ttime_samples;
72 unsigned long ttime_mean;
73
Jens Axboe206dc692006-03-28 13:03:44 +020074 unsigned int seek_samples;
75 u64 seek_total;
76 sector_t seek_mean;
77
Al Virod9ff4182006-03-18 13:51:22 -050078 struct list_head queue_list;
79
Jens Axboee2d74ac2006-03-28 08:59:01 +020080 void (*dtor)(struct io_context *); /* destructor */
81 void (*exit)(struct io_context *); /* called on task exit */
Linus Torvalds1da177e2005-04-16 15:20:36 -070082};
83
84/*
85 * This is the per-process I/O subsystem state. It is refcounted and
86 * kmalloc'ed. Currently all fields are modified in process io context
87 * (apart from the atomic refcount), so require no locking.
88 */
89struct io_context {
90 atomic_t refcount;
Jens Axboe22e2c502005-06-27 10:55:12 +020091 struct task_struct *task;
92
Jens Axboefc463792006-08-29 09:05:44 +020093 unsigned int ioprio_changed;
Linus Torvalds1da177e2005-04-16 15:20:36 -070094
95 /*
96 * For request batching
97 */
98 unsigned long last_waited; /* Time last woken after wait for request */
99 int nr_batch_requests; /* Number of requests left in the batch */
100
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 struct as_io_context *aic;
Jens Axboee2d74ac2006-03-28 08:59:01 +0200102 struct rb_root cic_root;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103};
104
105void put_io_context(struct io_context *ioc);
106void exit_io_context(void);
Jens Axboeb5deef92006-07-19 23:39:40 +0200107struct io_context *get_io_context(gfp_t gfp_flags, int node);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108void copy_io_context(struct io_context **pdst, struct io_context **psrc);
109void swap_io_context(struct io_context **ioc1, struct io_context **ioc2);
110
111struct request;
Tejun Heo8ffdc652006-01-06 09:49:03 +0100112typedef void (rq_end_io_fn)(struct request *, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113
114struct request_list {
115 int count[2];
116 int starved[2];
Tejun Heocb98fc82005-10-28 08:29:39 +0200117 int elvpriv;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118 mempool_t *rq_pool;
119 wait_queue_head_t wait[2];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120};
121
Jens Axboe4aff5e22006-08-10 08:44:47 +0200122/*
123 * request command types
124 */
125enum rq_cmd_type_bits {
126 REQ_TYPE_FS = 1, /* fs request */
127 REQ_TYPE_BLOCK_PC, /* scsi command */
128 REQ_TYPE_SENSE, /* sense request */
129 REQ_TYPE_PM_SUSPEND, /* suspend request */
130 REQ_TYPE_PM_RESUME, /* resume request */
131 REQ_TYPE_PM_SHUTDOWN, /* shutdown request */
132 REQ_TYPE_FLUSH, /* flush request */
133 REQ_TYPE_SPECIAL, /* driver defined type */
134 REQ_TYPE_LINUX_BLOCK, /* generic block layer message */
135 /*
136 * for ATA/ATAPI devices. this really doesn't belong here, ide should
137 * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver
138 * private REQ_LB opcodes to differentiate what type of request this is
139 */
140 REQ_TYPE_ATA_CMD,
141 REQ_TYPE_ATA_TASK,
142 REQ_TYPE_ATA_TASKFILE,
143};
144
145/*
146 * For request of type REQ_TYPE_LINUX_BLOCK, rq->cmd[0] is the opcode being
147 * sent down (similar to how REQ_TYPE_BLOCK_PC means that ->cmd[] holds a
148 * SCSI cdb.
149 *
150 * 0x00 -> 0x3f are driver private, to be used for whatever purpose they need,
151 * typically to differentiate REQ_TYPE_SPECIAL requests.
152 *
153 */
154enum {
155 /*
156 * just examples for now
157 */
158 REQ_LB_OP_EJECT = 0x40, /* eject request */
159 REQ_LB_OP_FLUSH = 0x41, /* flush device */
160};
161
162/*
163 * request type modified bits. first three bits match BIO_RW* bits, important
164 */
165enum rq_flag_bits {
166 __REQ_RW, /* not set, read. set, write */
167 __REQ_FAILFAST, /* no low level driver retries */
168 __REQ_SORTED, /* elevator knows about this request */
169 __REQ_SOFTBARRIER, /* may not be passed by ioscheduler */
170 __REQ_HARDBARRIER, /* may not be passed by drive either */
171 __REQ_FUA, /* forced unit access */
172 __REQ_NOMERGE, /* don't touch this for merging */
173 __REQ_STARTED, /* drive already may have started this one */
174 __REQ_DONTPREP, /* don't call prep for this one */
175 __REQ_QUEUED, /* uses queueing */
176 __REQ_ELVPRIV, /* elevator private data attached */
177 __REQ_FAILED, /* set if the request failed */
178 __REQ_QUIET, /* don't worry about errors */
179 __REQ_PREEMPT, /* set for "ide_preempt" requests */
180 __REQ_ORDERED_COLOR, /* is before or after barrier */
181 __REQ_RW_SYNC, /* request is sync (O_DIRECT) */
Jens Axboe49171e52006-08-10 08:59:11 +0200182 __REQ_ALLOCED, /* request came from our alloc pool */
Jens Axboe5404bc72006-08-10 09:01:02 +0200183 __REQ_RW_META, /* metadata io request */
Jens Axboe4aff5e22006-08-10 08:44:47 +0200184 __REQ_NR_BITS, /* stops here */
185};
186
187#define REQ_RW (1 << __REQ_RW)
188#define REQ_FAILFAST (1 << __REQ_FAILFAST)
189#define REQ_SORTED (1 << __REQ_SORTED)
190#define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER)
191#define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER)
192#define REQ_FUA (1 << __REQ_FUA)
193#define REQ_NOMERGE (1 << __REQ_NOMERGE)
194#define REQ_STARTED (1 << __REQ_STARTED)
195#define REQ_DONTPREP (1 << __REQ_DONTPREP)
196#define REQ_QUEUED (1 << __REQ_QUEUED)
197#define REQ_ELVPRIV (1 << __REQ_ELVPRIV)
198#define REQ_FAILED (1 << __REQ_FAILED)
199#define REQ_QUIET (1 << __REQ_QUIET)
200#define REQ_PREEMPT (1 << __REQ_PREEMPT)
201#define REQ_ORDERED_COLOR (1 << __REQ_ORDERED_COLOR)
202#define REQ_RW_SYNC (1 << __REQ_RW_SYNC)
Jens Axboe49171e52006-08-10 08:59:11 +0200203#define REQ_ALLOCED (1 << __REQ_ALLOCED)
Jens Axboe5404bc72006-08-10 09:01:02 +0200204#define REQ_RW_META (1 << __REQ_RW_META)
Jens Axboe4aff5e22006-08-10 08:44:47 +0200205
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206#define BLK_MAX_CDB 16
207
208/*
209 * try to put the fields that are referenced together in the same cacheline
210 */
211struct request {
Jens Axboeff856ba2006-01-09 16:02:34 +0100212 struct list_head queuelist;
213 struct list_head donelist;
214
Jens Axboee6a1c872006-08-10 09:00:21 +0200215 request_queue_t *q;
216
Jens Axboe4aff5e22006-08-10 08:44:47 +0200217 unsigned int cmd_flags;
218 enum rq_cmd_type_bits cmd_type;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219
220 /* Maintain bio traversal state for part by part I/O submission.
221 * hard_* are block layer internals, no driver should touch them!
222 */
223
224 sector_t sector; /* next sector to submit */
Jens Axboee6a1c872006-08-10 09:00:21 +0200225 sector_t hard_sector; /* next sector to complete */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226 unsigned long nr_sectors; /* no. of sectors left to submit */
Jens Axboee6a1c872006-08-10 09:00:21 +0200227 unsigned long hard_nr_sectors; /* no. of sectors left to complete */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228 /* no. of sectors left to submit in the current segment */
229 unsigned int current_nr_sectors;
230
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231 /* no. of sectors left to complete in the current segment */
232 unsigned int hard_cur_sectors;
233
234 struct bio *bio;
235 struct bio *biotail;
236
Jens Axboe98170642006-07-28 09:23:08 +0200237 struct hlist_node hash; /* merge hash */
Jens Axboee6a1c872006-08-10 09:00:21 +0200238 /*
239 * The rb_node is only used inside the io scheduler, requests
240 * are pruned when moved to the dispatch queue. So let the
241 * completion_data share space with the rb_node.
242 */
243 union {
244 struct rb_node rb_node; /* sort/lookup */
245 void *completion_data;
246 };
Jens Axboe98170642006-07-28 09:23:08 +0200247
Jens Axboeff7d1452006-07-12 14:04:37 +0200248 /*
249 * two pointers are available for the IO schedulers, if they need
250 * more they have to dynamically allocate it.
251 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252 void *elevator_private;
Jens Axboeff7d1452006-07-12 14:04:37 +0200253 void *elevator_private2;
254
Jens Axboe8f34ee72006-06-13 09:02:34 +0200255 struct gendisk *rq_disk;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256 unsigned long start_time;
257
258 /* Number of scatter-gather DMA addr+len pairs after
259 * physical address coalescing is performed.
260 */
261 unsigned short nr_phys_segments;
262
263 /* Number of scatter-gather addr+len pairs after
264 * physical and DMA remapping hardware coalescing is performed.
265 * This is the number of scatter-gather entries the driver
266 * will actually have to deal with after DMA mapping is done.
267 */
268 unsigned short nr_hw_segments;
269
Jens Axboe8f34ee72006-06-13 09:02:34 +0200270 unsigned short ioprio;
271
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272 void *special;
Jens Axboe8f34ee72006-06-13 09:02:34 +0200273 char *buffer;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274
Jens Axboecdd60262006-07-28 09:32:07 +0200275 int tag;
276 int errors;
277
278 int ref_count;
279
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280 /*
281 * when request is used as a packet command carrier
282 */
283 unsigned int cmd_len;
284 unsigned char cmd[BLK_MAX_CDB];
285
286 unsigned int data_len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 unsigned int sense_len;
Jens Axboe8f34ee72006-06-13 09:02:34 +0200288 void *data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289 void *sense;
290
291 unsigned int timeout;
Mike Christie17e01f22005-11-11 05:31:37 -0600292 int retries;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293
294 /*
Jens Axboec00895a2006-09-30 20:29:12 +0200295 * completion callback.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296 */
297 rq_end_io_fn *end_io;
298 void *end_io_data;
299};
300
301/*
Jens Axboe4aff5e22006-08-10 08:44:47 +0200302 * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303 * requests. Some step values could eventually be made generic.
304 */
305struct request_pm_state
306{
307 /* PM state machine step value, currently driver specific */
308 int pm_step;
309 /* requested PM state value (S1, S2, S3, S4, ...) */
310 u32 pm_state;
311 void* data; /* for driver use */
312};
313
314#include <linux/elevator.h>
315
316typedef int (merge_request_fn) (request_queue_t *, struct request *,
317 struct bio *);
318typedef int (merge_requests_fn) (request_queue_t *, struct request *,
319 struct request *);
320typedef void (request_fn_proc) (request_queue_t *q);
321typedef int (make_request_fn) (request_queue_t *q, struct bio *bio);
322typedef int (prep_rq_fn) (request_queue_t *, struct request *);
323typedef void (unplug_fn) (request_queue_t *);
324
325struct bio_vec;
326typedef int (merge_bvec_fn) (request_queue_t *, struct bio *, struct bio_vec *);
327typedef void (activity_fn) (void *data, int rw);
328typedef int (issue_flush_fn) (request_queue_t *, struct gendisk *, sector_t *);
Tejun Heo797e7db2006-01-06 09:51:03 +0100329typedef void (prepare_flush_fn) (request_queue_t *, struct request *);
Jens Axboeff856ba2006-01-09 16:02:34 +0100330typedef void (softirq_done_fn)(struct request *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331
332enum blk_queue_state {
333 Queue_down,
334 Queue_up,
335};
336
Linus Torvalds1da177e2005-04-16 15:20:36 -0700337struct blk_queue_tag {
338 struct request **tag_index; /* map of busy tags */
339 unsigned long *tag_map; /* bit map of free/busy tags */
340 struct list_head busy_list; /* fifo list of busy tags */
341 int busy; /* current depth */
342 int max_depth; /* what we will send to device */
Tejun Heoba025082005-08-05 13:28:11 -0700343 int real_max_depth; /* what the array can hold */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344 atomic_t refcnt; /* map can be shared */
345};
346
347struct request_queue
348{
349 /*
350 * Together with queue_head for cacheline sharing
351 */
352 struct list_head queue_head;
353 struct request *last_merge;
354 elevator_t *elevator;
355
356 /*
357 * the queue request freelist, one for reads and one for writes
358 */
359 struct request_list rq;
360
361 request_fn_proc *request_fn;
362 merge_request_fn *back_merge_fn;
363 merge_request_fn *front_merge_fn;
364 merge_requests_fn *merge_requests_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 activity_fn *activity_fn;
370 issue_flush_fn *issue_flush_fn;
371 prepare_flush_fn *prepare_flush_fn;
Jens Axboeff856ba2006-01-09 16:02:34 +0100372 softirq_done_fn *softirq_done_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373
374 /*
Tejun Heo8922e162005-10-20 16:23:44 +0200375 * Dispatch queue sorting
376 */
Jens Axboe1b47f532005-10-20 16:37:00 +0200377 sector_t end_sector;
Tejun Heo8922e162005-10-20 16:23:44 +0200378 struct request *boundary_rq;
Tejun Heo8922e162005-10-20 16:23:44 +0200379
380 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381 * Auto-unplugging state
382 */
383 struct timer_list unplug_timer;
384 int unplug_thresh; /* After this many requests */
385 unsigned long unplug_delay; /* After this many jiffies */
386 struct work_struct unplug_work;
387
388 struct backing_dev_info backing_dev_info;
389
390 /*
391 * The queue owner gets to use this for whatever they like.
392 * ll_rw_blk doesn't touch it.
393 */
394 void *queuedata;
395
396 void *activity_data;
397
398 /*
399 * queue needs bounce pages for pages above this limit
400 */
401 unsigned long bounce_pfn;
Al Viro8267e262005-10-21 03:20:53 -0400402 gfp_t bounce_gfp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403
404 /*
405 * various queue flags, see QUEUE_* below
406 */
407 unsigned long queue_flags;
408
409 /*
152587d2005-04-12 16:22:06 -0500410 * protects queue structures from reentrancy. ->__queue_lock should
411 * _never_ be used directly, it is queue private. always use
412 * ->queue_lock.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413 */
152587d2005-04-12 16:22:06 -0500414 spinlock_t __queue_lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415 spinlock_t *queue_lock;
416
417 /*
418 * queue kobject
419 */
420 struct kobject kobj;
421
422 /*
423 * queue settings
424 */
425 unsigned long nr_requests; /* Max # of requests */
426 unsigned int nr_congestion_on;
427 unsigned int nr_congestion_off;
428 unsigned int nr_batching;
429
Jens Axboe2cb2e142006-01-17 09:04:32 +0100430 unsigned int max_sectors;
431 unsigned int max_hw_sectors;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432 unsigned short max_phys_segments;
433 unsigned short max_hw_segments;
434 unsigned short hardsect_size;
435 unsigned int max_segment_size;
436
437 unsigned long seg_boundary_mask;
438 unsigned int dma_alignment;
439
440 struct blk_queue_tag *queue_tags;
441
Tejun Heo15853af2005-11-10 08:52:05 +0100442 unsigned int nr_sorted;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700443 unsigned int in_flight;
444
445 /*
446 * sg stuff
447 */
448 unsigned int sg_timeout;
449 unsigned int sg_reserved_size;
Christoph Lameter19460892005-06-23 00:08:19 -0700450 int node;
Alexey Dobriyan6c5c9342006-09-29 01:59:40 -0700451#ifdef CONFIG_BLK_DEV_IO_TRACE
Jens Axboe2056a782006-03-23 20:00:26 +0100452 struct blk_trace *blk_trace;
Alexey Dobriyan6c5c9342006-09-29 01:59:40 -0700453#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700454 /*
455 * reserved for flush operations
456 */
Tejun Heo797e7db2006-01-06 09:51:03 +0100457 unsigned int ordered, next_ordered, ordseq;
458 int orderr, ordcolor;
459 struct request pre_flush_rq, bar_rq, post_flush_rq;
460 struct request *orig_bar_rq;
461 unsigned int bi_size;
Al Viro483f4af2006-03-18 18:34:37 -0500462
463 struct mutex sysfs_lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464};
465
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466#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 /* write queue has been filled */
470#define QUEUE_FLAG_WRITEFULL 4 /* read 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 */
Jens Axboe64521d12005-10-28 08:30:39 +0200474#define QUEUE_FLAG_ELVSWITCH 8 /* don't use elevator, just do FIFO */
Tejun Heo797e7db2006-01-06 09:51:03 +0100475
476enum {
477 /*
478 * Hardbarrier is supported with one of the following methods.
479 *
480 * NONE : hardbarrier unsupported
481 * DRAIN : ordering by draining is enough
482 * DRAIN_FLUSH : ordering by draining w/ pre and post flushes
483 * DRAIN_FUA : ordering by draining w/ pre flush and FUA write
484 * TAG : ordering by tag is enough
485 * TAG_FLUSH : ordering by tag w/ pre and post flushes
486 * TAG_FUA : ordering by tag w/ pre flush and FUA write
487 */
488 QUEUE_ORDERED_NONE = 0x00,
489 QUEUE_ORDERED_DRAIN = 0x01,
490 QUEUE_ORDERED_TAG = 0x02,
491
492 QUEUE_ORDERED_PREFLUSH = 0x10,
493 QUEUE_ORDERED_POSTFLUSH = 0x20,
494 QUEUE_ORDERED_FUA = 0x40,
495
496 QUEUE_ORDERED_DRAIN_FLUSH = QUEUE_ORDERED_DRAIN |
497 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
498 QUEUE_ORDERED_DRAIN_FUA = QUEUE_ORDERED_DRAIN |
499 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
500 QUEUE_ORDERED_TAG_FLUSH = QUEUE_ORDERED_TAG |
501 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
502 QUEUE_ORDERED_TAG_FUA = QUEUE_ORDERED_TAG |
503 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
504
505 /*
506 * Ordered operation sequence
507 */
508 QUEUE_ORDSEQ_STARTED = 0x01, /* flushing in progress */
509 QUEUE_ORDSEQ_DRAIN = 0x02, /* waiting for the queue to be drained */
510 QUEUE_ORDSEQ_PREFLUSH = 0x04, /* pre-flushing in progress */
511 QUEUE_ORDSEQ_BAR = 0x08, /* original barrier req in progress */
512 QUEUE_ORDSEQ_POSTFLUSH = 0x10, /* post-flushing in progress */
513 QUEUE_ORDSEQ_DONE = 0x20,
514};
Linus Torvalds1da177e2005-04-16 15:20:36 -0700515
516#define blk_queue_plugged(q) test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
517#define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
518#define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
Tejun Heo797e7db2006-01-06 09:51:03 +0100519#define blk_queue_flushing(q) ((q)->ordseq)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520
Jens Axboe4aff5e22006-08-10 08:44:47 +0200521#define blk_fs_request(rq) ((rq)->cmd_type == REQ_TYPE_FS)
522#define blk_pc_request(rq) ((rq)->cmd_type == REQ_TYPE_BLOCK_PC)
523#define blk_special_request(rq) ((rq)->cmd_type == REQ_TYPE_SPECIAL)
524#define blk_sense_request(rq) ((rq)->cmd_type == REQ_TYPE_SENSE)
525
526#define blk_noretry_request(rq) ((rq)->cmd_flags & REQ_FAILFAST)
527#define blk_rq_started(rq) ((rq)->cmd_flags & REQ_STARTED)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700528
529#define blk_account_rq(rq) (blk_rq_started(rq) && blk_fs_request(rq))
530
Jens Axboe4aff5e22006-08-10 08:44:47 +0200531#define blk_pm_suspend_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND)
532#define blk_pm_resume_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_RESUME)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533#define blk_pm_request(rq) \
Jens Axboe4aff5e22006-08-10 08:44:47 +0200534 (blk_pm_suspend_request(rq) || blk_pm_resume_request(rq))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535
Jens Axboe4aff5e22006-08-10 08:44:47 +0200536#define blk_sorted_rq(rq) ((rq)->cmd_flags & REQ_SORTED)
537#define blk_barrier_rq(rq) ((rq)->cmd_flags & REQ_HARDBARRIER)
538#define blk_fua_rq(rq) ((rq)->cmd_flags & REQ_FUA)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700539
540#define list_entry_rq(ptr) list_entry((ptr), struct request, queuelist)
541
Jens Axboe4aff5e22006-08-10 08:44:47 +0200542#define rq_data_dir(rq) ((rq)->cmd_flags & 1)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543
Jens Axboe9e2585a2006-07-28 09:26:13 +0200544/*
545 * We regard a request as sync, if it's a READ or a SYNC write.
546 */
547#define rq_is_sync(rq) (rq_data_dir((rq)) == READ || (rq)->cmd_flags & REQ_RW_SYNC)
Jens Axboe5404bc72006-08-10 09:01:02 +0200548#define rq_is_meta(rq) ((rq)->cmd_flags & REQ_RW_META)
Jens Axboe9e2585a2006-07-28 09:26:13 +0200549
Linus Torvalds1da177e2005-04-16 15:20:36 -0700550static inline int blk_queue_full(struct request_queue *q, int rw)
551{
552 if (rw == READ)
553 return test_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
554 return test_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
555}
556
557static inline void blk_set_queue_full(struct request_queue *q, int rw)
558{
559 if (rw == READ)
560 set_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
561 else
562 set_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
563}
564
565static inline void blk_clear_queue_full(struct request_queue *q, int rw)
566{
567 if (rw == READ)
568 clear_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
569 else
570 clear_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
571}
572
573
574/*
575 * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
576 * it already be started by driver.
577 */
578#define RQ_NOMERGE_FLAGS \
579 (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER)
580#define rq_mergeable(rq) \
Jens Axboe4aff5e22006-08-10 08:44:47 +0200581 (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && blk_fs_request((rq)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700582
583/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584 * q->prep_rq_fn return values
585 */
586#define BLKPREP_OK 0 /* serve it */
587#define BLKPREP_KILL 1 /* fatal error, kill */
588#define BLKPREP_DEFER 2 /* leave on queue */
589
590extern unsigned long blk_max_low_pfn, blk_max_pfn;
591
592/*
593 * standard bounce addresses:
594 *
595 * BLK_BOUNCE_HIGH : bounce all highmem pages
596 * BLK_BOUNCE_ANY : don't bounce anything
597 * BLK_BOUNCE_ISA : bounce pages above ISA DMA boundary
598 */
599#define BLK_BOUNCE_HIGH ((u64)blk_max_low_pfn << PAGE_SHIFT)
600#define BLK_BOUNCE_ANY ((u64)blk_max_pfn << PAGE_SHIFT)
601#define BLK_BOUNCE_ISA (ISA_DMA_THRESHOLD)
602
603#ifdef CONFIG_MMU
604extern int init_emergency_isa_pool(void);
605extern void blk_queue_bounce(request_queue_t *q, struct bio **bio);
606#else
607static inline int init_emergency_isa_pool(void)
608{
609 return 0;
610}
611static inline void blk_queue_bounce(request_queue_t *q, struct bio **bio)
612{
613}
614#endif /* CONFIG_MMU */
615
616#define rq_for_each_bio(_bio, rq) \
617 if ((rq->bio)) \
618 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
619
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620extern int blk_register_queue(struct gendisk *disk);
621extern void blk_unregister_queue(struct gendisk *disk);
622extern void register_disk(struct gendisk *dev);
623extern void generic_make_request(struct bio *bio);
624extern void blk_put_request(struct request *);
Mike Christie6e39b692005-11-11 05:30:24 -0600625extern void __blk_put_request(request_queue_t *, struct request *);
Tejun Heo8ffdc652006-01-06 09:49:03 +0100626extern void blk_end_sync_rq(struct request *rq, int error);
Al Viro8267e262005-10-21 03:20:53 -0400627extern struct request *blk_get_request(request_queue_t *, int, gfp_t);
Tejun Heo 867d1192005-04-24 02:06:05 -0500628extern void blk_insert_request(request_queue_t *, struct request *, int, void *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629extern void blk_requeue_request(request_queue_t *, struct request *);
630extern void blk_plug_device(request_queue_t *);
631extern int blk_remove_plug(request_queue_t *);
632extern void blk_recount_segments(request_queue_t *, struct bio *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633extern int scsi_cmd_ioctl(struct file *, struct gendisk *, unsigned int, void __user *);
Christoph Hellwig21b2f0c2006-03-22 17:52:04 +0100634extern int sg_scsi_ioctl(struct file *, struct request_queue *,
635 struct gendisk *, struct scsi_ioctl_command __user *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700636extern void blk_start_queue(request_queue_t *q);
637extern void blk_stop_queue(request_queue_t *q);
638extern void blk_sync_queue(struct request_queue *q);
639extern void __blk_stop_queue(request_queue_t *q);
640extern void blk_run_queue(request_queue_t *);
Jens Axboedc72ef42006-07-20 14:54:05 +0200641extern void blk_start_queueing(request_queue_t *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700642extern void blk_queue_activity_fn(request_queue_t *, activity_fn *, void *);
Jens Axboedd1cab92005-06-20 14:06:01 +0200643extern int blk_rq_map_user(request_queue_t *, struct request *, void __user *, unsigned int);
644extern int blk_rq_unmap_user(struct bio *, unsigned int);
Al Viro8267e262005-10-21 03:20:53 -0400645extern int blk_rq_map_kern(request_queue_t *, struct request *, void *, unsigned int, gfp_t);
James Bottomley f1970ba2005-06-20 14:06:52 +0200646extern int blk_rq_map_user_iov(request_queue_t *, struct request *, struct sg_iovec *, int);
James Bottomley 994ca9a2005-06-20 14:11:09 +0200647extern int blk_execute_rq(request_queue_t *, struct gendisk *,
648 struct request *, int);
Mike Christie6e39b692005-11-11 05:30:24 -0600649extern void blk_execute_rq_nowait(request_queue_t *, struct gendisk *,
Jens Axboe15fc8582006-01-06 10:00:50 +0100650 struct request *, int, rq_end_io_fn *);
Mike Christie6e39b692005-11-11 05:30:24 -0600651
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652static inline request_queue_t *bdev_get_queue(struct block_device *bdev)
653{
654 return bdev->bd_disk->queue;
655}
656
657static inline void blk_run_backing_dev(struct backing_dev_info *bdi,
658 struct page *page)
659{
660 if (bdi && bdi->unplug_io_fn)
661 bdi->unplug_io_fn(bdi, page);
662}
663
664static inline void blk_run_address_space(struct address_space *mapping)
665{
666 if (mapping)
667 blk_run_backing_dev(mapping->backing_dev_info, NULL);
668}
669
670/*
671 * end_request() and friends. Must be called with the request queue spinlock
672 * acquired. All functions called within end_request() _must_be_ atomic.
673 *
674 * Several drivers define their own end_request and call
675 * end_that_request_first() and end_that_request_last()
676 * for parts of the original function. This prevents
677 * code duplication in drivers.
678 */
679extern int end_that_request_first(struct request *, int, int);
680extern int end_that_request_chunk(struct request *, int, int);
Tejun Heo8ffdc652006-01-06 09:49:03 +0100681extern void end_that_request_last(struct request *, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700682extern void end_request(struct request *req, int uptodate);
Jens Axboeff856ba2006-01-09 16:02:34 +0100683extern void blk_complete_request(struct request *);
684
Linus Torvalds1da177e2005-04-16 15:20:36 -0700685/*
686 * end_that_request_first/chunk() takes an uptodate argument. we account
687 * any value <= as an io error. 0 means -EIO for compatability reasons,
688 * any other < 0 value is the direct error type. An uptodate value of
689 * 1 indicates successful io completion
690 */
691#define end_io_error(uptodate) (unlikely((uptodate) <= 0))
692
693static inline void blkdev_dequeue_request(struct request *req)
694{
Tejun Heo8922e162005-10-20 16:23:44 +0200695 elv_dequeue_request(req->q, req);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700696}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700697
Linus Torvalds1da177e2005-04-16 15:20:36 -0700698/*
699 * Access functions for manipulating queue properties
700 */
Christoph Lameter19460892005-06-23 00:08:19 -0700701extern request_queue_t *blk_init_queue_node(request_fn_proc *rfn,
702 spinlock_t *lock, int node_id);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700703extern request_queue_t *blk_init_queue(request_fn_proc *, spinlock_t *);
704extern void blk_cleanup_queue(request_queue_t *);
705extern void blk_queue_make_request(request_queue_t *, make_request_fn *);
706extern void blk_queue_bounce_limit(request_queue_t *, u64);
Jens Axboe2cb2e142006-01-17 09:04:32 +0100707extern void blk_queue_max_sectors(request_queue_t *, unsigned int);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700708extern void blk_queue_max_phys_segments(request_queue_t *, unsigned short);
709extern void blk_queue_max_hw_segments(request_queue_t *, unsigned short);
710extern void blk_queue_max_segment_size(request_queue_t *, unsigned int);
711extern void blk_queue_hardsect_size(request_queue_t *, unsigned short);
712extern void blk_queue_stack_limits(request_queue_t *t, request_queue_t *b);
713extern void blk_queue_segment_boundary(request_queue_t *, unsigned long);
714extern void blk_queue_prep_rq(request_queue_t *, prep_rq_fn *pfn);
715extern void blk_queue_merge_bvec(request_queue_t *, merge_bvec_fn *);
716extern void blk_queue_dma_alignment(request_queue_t *, int);
Jens Axboeff856ba2006-01-09 16:02:34 +0100717extern void blk_queue_softirq_done(request_queue_t *, softirq_done_fn *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700718extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
Tejun Heo797e7db2006-01-06 09:51:03 +0100719extern int blk_queue_ordered(request_queue_t *, unsigned, prepare_flush_fn *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700720extern void blk_queue_issue_flush_fn(request_queue_t *, issue_flush_fn *);
Tejun Heo797e7db2006-01-06 09:51:03 +0100721extern int blk_do_ordered(request_queue_t *, struct request **);
722extern unsigned blk_ordered_cur_seq(request_queue_t *);
723extern unsigned blk_ordered_req_seq(struct request *);
724extern void blk_ordered_complete_seq(request_queue_t *, unsigned, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700725
726extern int blk_rq_map_sg(request_queue_t *, struct request *, struct scatterlist *);
727extern void blk_dump_rq_flags(struct request *, char *);
728extern void generic_unplug_device(request_queue_t *);
729extern void __generic_unplug_device(request_queue_t *);
730extern long nr_blockdev_pages(void);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700731
732int blk_get_queue(request_queue_t *);
Al Viro8267e262005-10-21 03:20:53 -0400733request_queue_t *blk_alloc_queue(gfp_t);
734request_queue_t *blk_alloc_queue_node(gfp_t, int);
Al Viro483f4af2006-03-18 18:34:37 -0500735extern void blk_put_queue(request_queue_t *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700736
737/*
738 * tag stuff
739 */
740#define blk_queue_tag_depth(q) ((q)->queue_tags->busy)
741#define blk_queue_tag_queue(q) ((q)->queue_tags->busy < (q)->queue_tags->max_depth)
Jens Axboe4aff5e22006-08-10 08:44:47 +0200742#define blk_rq_tagged(rq) ((rq)->cmd_flags & REQ_QUEUED)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743extern int blk_queue_start_tag(request_queue_t *, struct request *);
744extern struct request *blk_queue_find_tag(request_queue_t *, int);
745extern void blk_queue_end_tag(request_queue_t *, struct request *);
746extern int blk_queue_init_tags(request_queue_t *, int, struct blk_queue_tag *);
747extern void blk_queue_free_tags(request_queue_t *);
748extern int blk_queue_resize_tags(request_queue_t *, int);
749extern void blk_queue_invalidate_tags(request_queue_t *);
750extern long blk_congestion_wait(int rw, long timeout);
James Bottomley492dfb42006-08-30 15:48:45 -0400751extern struct blk_queue_tag *blk_init_tags(int);
752extern void blk_free_tags(struct blk_queue_tag *);
Trond Myklebust275a0822006-08-22 20:06:24 -0400753extern void blk_congestion_end(int rw);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700754
755extern void blk_rq_bio_prep(request_queue_t *, struct request *, struct bio *);
756extern int blkdev_issue_flush(struct block_device *, sector_t *);
757
758#define MAX_PHYS_SEGMENTS 128
759#define MAX_HW_SEGMENTS 128
Mike Christiedefd94b2005-12-05 02:37:06 -0600760#define SAFE_MAX_SECTORS 255
761#define BLK_DEF_MAX_SECTORS 1024
Linus Torvalds1da177e2005-04-16 15:20:36 -0700762
763#define MAX_SEGMENT_SIZE 65536
764
765#define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
766
Linus Torvalds1da177e2005-04-16 15:20:36 -0700767static inline int queue_hardsect_size(request_queue_t *q)
768{
769 int retval = 512;
770
771 if (q && q->hardsect_size)
772 retval = q->hardsect_size;
773
774 return retval;
775}
776
777static inline int bdev_hardsect_size(struct block_device *bdev)
778{
779 return queue_hardsect_size(bdev_get_queue(bdev));
780}
781
782static inline int queue_dma_alignment(request_queue_t *q)
783{
784 int retval = 511;
785
786 if (q && q->dma_alignment)
787 retval = q->dma_alignment;
788
789 return retval;
790}
791
Linus Torvalds1da177e2005-04-16 15:20:36 -0700792/* assumes size > 256 */
793static inline unsigned int blksize_bits(unsigned int size)
794{
795 unsigned int bits = 8;
796 do {
797 bits++;
798 size >>= 1;
799 } while (size > 256);
800 return bits;
801}
802
Adrian Bunk2befb9e2005-09-10 00:27:17 -0700803static inline unsigned int block_size(struct block_device *bdev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700804{
805 return bdev->bd_block_size;
806}
807
808typedef struct {struct page *v;} Sector;
809
810unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
811
812static inline void put_dev_sector(Sector p)
813{
814 page_cache_release(p.v);
815}
816
817struct work_struct;
818int kblockd_schedule_work(struct work_struct *work);
819void kblockd_flush(void);
820
821#ifdef CONFIG_LBD
822# include <asm/div64.h>
823# define sector_div(a, b) do_div(a, b)
824#else
825# define sector_div(n, b)( \
826{ \
827 int _res; \
828 _res = (n) % (b); \
829 (n) /= (b); \
830 _res; \
831} \
832)
833#endif
834
835#define MODULE_ALIAS_BLOCKDEV(major,minor) \
836 MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
837#define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
838 MODULE_ALIAS("block-major-" __stringify(major) "-*")
839
840
841#endif