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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#ifndef _LINUX_BLKDEV_H
2#define _LINUX_BLKDEV_H
3
Jens Axboef5ff8422007-09-21 09:19:54 +02004#ifdef CONFIG_BLOCK
5
Andrew Mortonbcfd8d32006-08-31 12:56:06 +02006#include <linux/sched.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07007#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>
FUJITA Tomonorid351af02007-07-09 12:40:35 +020019#include <linux/bsg.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070020
21#include <asm/scatterlist.h>
22
Christoph Hellwig21b2f0c2006-03-22 17:52:04 +010023struct scsi_ioctl_command;
24
Linus Torvalds1da177e2005-04-16 15:20:36 -070025struct request_queue;
Jens Axboe71f65e62007-07-24 10:29:42 +020026typedef struct request_queue request_queue_t __deprecated;
Linus Torvalds1da177e2005-04-16 15:20:36 -070027struct elevator_queue;
28typedef struct elevator_queue elevator_t;
29struct request_pm_state;
Jens Axboe2056a782006-03-23 20:00:26 +010030struct blk_trace;
Jens Axboe3d6392c2007-07-09 12:38:05 +020031struct request;
32struct sg_io_hdr;
Linus Torvalds1da177e2005-04-16 15:20:36 -070033
34#define BLKDEV_MIN_RQ 4
35#define BLKDEV_MAX_RQ 128 /* Default maximum */
36
Jens Axboed38ecf92008-01-24 08:53:35 +010037int put_io_context(struct io_context *ioc);
Linus Torvalds1da177e2005-04-16 15:20:36 -070038void exit_io_context(void);
Jens Axboeb5deef92006-07-19 23:39:40 +020039struct io_context *get_io_context(gfp_t gfp_flags, int node);
Jens Axboefd0928d2008-01-24 08:52:45 +010040struct io_context *alloc_io_context(gfp_t gfp_flags, int node);
Linus Torvalds1da177e2005-04-16 15:20:36 -070041void copy_io_context(struct io_context **pdst, struct io_context **psrc);
Linus Torvalds1da177e2005-04-16 15:20:36 -070042
43struct request;
Tejun Heo8ffdc652006-01-06 09:49:03 +010044typedef void (rq_end_io_fn)(struct request *, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -070045
46struct request_list {
47 int count[2];
48 int starved[2];
Tejun Heocb98fc82005-10-28 08:29:39 +020049 int elvpriv;
Linus Torvalds1da177e2005-04-16 15:20:36 -070050 mempool_t *rq_pool;
51 wait_queue_head_t wait[2];
Linus Torvalds1da177e2005-04-16 15:20:36 -070052};
53
Jens Axboe4aff5e22006-08-10 08:44:47 +020054/*
55 * request command types
56 */
57enum rq_cmd_type_bits {
58 REQ_TYPE_FS = 1, /* fs request */
59 REQ_TYPE_BLOCK_PC, /* scsi command */
60 REQ_TYPE_SENSE, /* sense request */
61 REQ_TYPE_PM_SUSPEND, /* suspend request */
62 REQ_TYPE_PM_RESUME, /* resume request */
63 REQ_TYPE_PM_SHUTDOWN, /* shutdown request */
64 REQ_TYPE_FLUSH, /* flush request */
65 REQ_TYPE_SPECIAL, /* driver defined type */
66 REQ_TYPE_LINUX_BLOCK, /* generic block layer message */
67 /*
68 * for ATA/ATAPI devices. this really doesn't belong here, ide should
69 * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver
70 * private REQ_LB opcodes to differentiate what type of request this is
71 */
Jens Axboe4aff5e22006-08-10 08:44:47 +020072 REQ_TYPE_ATA_TASKFILE,
Jens Axboecea28852006-10-12 15:08:45 +020073 REQ_TYPE_ATA_PC,
Jens Axboe4aff5e22006-08-10 08:44:47 +020074};
75
76/*
77 * For request of type REQ_TYPE_LINUX_BLOCK, rq->cmd[0] is the opcode being
78 * sent down (similar to how REQ_TYPE_BLOCK_PC means that ->cmd[] holds a
79 * SCSI cdb.
80 *
81 * 0x00 -> 0x3f are driver private, to be used for whatever purpose they need,
82 * typically to differentiate REQ_TYPE_SPECIAL requests.
83 *
84 */
85enum {
86 /*
87 * just examples for now
88 */
89 REQ_LB_OP_EJECT = 0x40, /* eject request */
90 REQ_LB_OP_FLUSH = 0x41, /* flush device */
91};
92
93/*
94 * request type modified bits. first three bits match BIO_RW* bits, important
95 */
96enum rq_flag_bits {
97 __REQ_RW, /* not set, read. set, write */
98 __REQ_FAILFAST, /* no low level driver retries */
99 __REQ_SORTED, /* elevator knows about this request */
100 __REQ_SOFTBARRIER, /* may not be passed by ioscheduler */
101 __REQ_HARDBARRIER, /* may not be passed by drive either */
102 __REQ_FUA, /* forced unit access */
103 __REQ_NOMERGE, /* don't touch this for merging */
104 __REQ_STARTED, /* drive already may have started this one */
105 __REQ_DONTPREP, /* don't call prep for this one */
106 __REQ_QUEUED, /* uses queueing */
107 __REQ_ELVPRIV, /* elevator private data attached */
108 __REQ_FAILED, /* set if the request failed */
109 __REQ_QUIET, /* don't worry about errors */
110 __REQ_PREEMPT, /* set for "ide_preempt" requests */
111 __REQ_ORDERED_COLOR, /* is before or after barrier */
112 __REQ_RW_SYNC, /* request is sync (O_DIRECT) */
Jens Axboe49171e52006-08-10 08:59:11 +0200113 __REQ_ALLOCED, /* request came from our alloc pool */
Jens Axboe5404bc72006-08-10 09:01:02 +0200114 __REQ_RW_META, /* metadata io request */
Jens Axboe4aff5e22006-08-10 08:44:47 +0200115 __REQ_NR_BITS, /* stops here */
116};
117
118#define REQ_RW (1 << __REQ_RW)
119#define REQ_FAILFAST (1 << __REQ_FAILFAST)
120#define REQ_SORTED (1 << __REQ_SORTED)
121#define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER)
122#define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER)
123#define REQ_FUA (1 << __REQ_FUA)
124#define REQ_NOMERGE (1 << __REQ_NOMERGE)
125#define REQ_STARTED (1 << __REQ_STARTED)
126#define REQ_DONTPREP (1 << __REQ_DONTPREP)
127#define REQ_QUEUED (1 << __REQ_QUEUED)
128#define REQ_ELVPRIV (1 << __REQ_ELVPRIV)
129#define REQ_FAILED (1 << __REQ_FAILED)
130#define REQ_QUIET (1 << __REQ_QUIET)
131#define REQ_PREEMPT (1 << __REQ_PREEMPT)
132#define REQ_ORDERED_COLOR (1 << __REQ_ORDERED_COLOR)
133#define REQ_RW_SYNC (1 << __REQ_RW_SYNC)
Jens Axboe49171e52006-08-10 08:59:11 +0200134#define REQ_ALLOCED (1 << __REQ_ALLOCED)
Jens Axboe5404bc72006-08-10 09:01:02 +0200135#define REQ_RW_META (1 << __REQ_RW_META)
Jens Axboe4aff5e22006-08-10 08:44:47 +0200136
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137#define BLK_MAX_CDB 16
138
139/*
Jens Axboe63a71382008-02-08 12:41:03 +0100140 * try to put the fields that are referenced together in the same cacheline.
141 * if you modify this structure, be sure to check block/blk-core.c:rq_init()
142 * as well!
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143 */
144struct request {
Jens Axboeff856ba2006-01-09 16:02:34 +0100145 struct list_head queuelist;
146 struct list_head donelist;
147
Jens Axboe165125e2007-07-24 09:28:11 +0200148 struct request_queue *q;
Jens Axboee6a1c872006-08-10 09:00:21 +0200149
Jens Axboe4aff5e22006-08-10 08:44:47 +0200150 unsigned int cmd_flags;
151 enum rq_cmd_type_bits cmd_type;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152
153 /* Maintain bio traversal state for part by part I/O submission.
154 * hard_* are block layer internals, no driver should touch them!
155 */
156
157 sector_t sector; /* next sector to submit */
Jens Axboee6a1c872006-08-10 09:00:21 +0200158 sector_t hard_sector; /* next sector to complete */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159 unsigned long nr_sectors; /* no. of sectors left to submit */
Jens Axboee6a1c872006-08-10 09:00:21 +0200160 unsigned long hard_nr_sectors; /* no. of sectors left to complete */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161 /* no. of sectors left to submit in the current segment */
162 unsigned int current_nr_sectors;
163
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164 /* no. of sectors left to complete in the current segment */
165 unsigned int hard_cur_sectors;
166
167 struct bio *bio;
168 struct bio *biotail;
169
Jens Axboe98170642006-07-28 09:23:08 +0200170 struct hlist_node hash; /* merge hash */
Jens Axboee6a1c872006-08-10 09:00:21 +0200171 /*
172 * The rb_node is only used inside the io scheduler, requests
173 * are pruned when moved to the dispatch queue. So let the
174 * completion_data share space with the rb_node.
175 */
176 union {
177 struct rb_node rb_node; /* sort/lookup */
178 void *completion_data;
179 };
Jens Axboe98170642006-07-28 09:23:08 +0200180
Jens Axboeff7d1452006-07-12 14:04:37 +0200181 /*
182 * two pointers are available for the IO schedulers, if they need
183 * more they have to dynamically allocate it.
184 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 void *elevator_private;
Jens Axboeff7d1452006-07-12 14:04:37 +0200186 void *elevator_private2;
187
Jens Axboe8f34ee72006-06-13 09:02:34 +0200188 struct gendisk *rq_disk;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189 unsigned long start_time;
190
191 /* Number of scatter-gather DMA addr+len pairs after
192 * physical address coalescing is performed.
193 */
194 unsigned short nr_phys_segments;
195
196 /* Number of scatter-gather addr+len pairs after
197 * physical and DMA remapping hardware coalescing is performed.
198 * This is the number of scatter-gather entries the driver
199 * will actually have to deal with after DMA mapping is done.
200 */
201 unsigned short nr_hw_segments;
202
Jens Axboe8f34ee72006-06-13 09:02:34 +0200203 unsigned short ioprio;
204
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205 void *special;
Jens Axboe8f34ee72006-06-13 09:02:34 +0200206 char *buffer;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207
Jens Axboecdd60262006-07-28 09:32:07 +0200208 int tag;
209 int errors;
210
211 int ref_count;
212
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 /*
214 * when request is used as a packet command carrier
215 */
216 unsigned int cmd_len;
217 unsigned char cmd[BLK_MAX_CDB];
218
Tejun Heo6b007692008-02-19 11:36:35 +0100219 unsigned int raw_data_len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 unsigned int data_len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221 unsigned int sense_len;
Jens Axboe8f34ee72006-06-13 09:02:34 +0200222 void *data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223 void *sense;
224
225 unsigned int timeout;
Mike Christie17e01f22005-11-11 05:31:37 -0600226 int retries;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227
228 /*
Jens Axboec00895a2006-09-30 20:29:12 +0200229 * completion callback.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230 */
231 rq_end_io_fn *end_io;
232 void *end_io_data;
FUJITA Tomonoriabae1fd2007-07-16 08:52:14 +0200233
234 /* for bidi */
235 struct request *next_rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236};
237
238/*
Jens Axboe4aff5e22006-08-10 08:44:47 +0200239 * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240 * requests. Some step values could eventually be made generic.
241 */
242struct request_pm_state
243{
244 /* PM state machine step value, currently driver specific */
245 int pm_step;
246 /* requested PM state value (S1, S2, S3, S4, ...) */
247 u32 pm_state;
248 void* data; /* for driver use */
249};
250
251#include <linux/elevator.h>
252
Jens Axboe165125e2007-07-24 09:28:11 +0200253typedef void (request_fn_proc) (struct request_queue *q);
254typedef int (make_request_fn) (struct request_queue *q, struct bio *bio);
255typedef int (prep_rq_fn) (struct request_queue *, struct request *);
256typedef void (unplug_fn) (struct request_queue *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257
258struct bio_vec;
Jens Axboe165125e2007-07-24 09:28:11 +0200259typedef int (merge_bvec_fn) (struct request_queue *, struct bio *, struct bio_vec *);
Jens Axboe165125e2007-07-24 09:28:11 +0200260typedef void (prepare_flush_fn) (struct request_queue *, struct request *);
Jens Axboeff856ba2006-01-09 16:02:34 +0100261typedef void (softirq_done_fn)(struct request *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262
263enum blk_queue_state {
264 Queue_down,
265 Queue_up,
266};
267
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268struct blk_queue_tag {
269 struct request **tag_index; /* map of busy tags */
270 unsigned long *tag_map; /* bit map of free/busy tags */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 int busy; /* current depth */
272 int max_depth; /* what we will send to device */
Tejun Heoba025082005-08-05 13:28:11 -0700273 int real_max_depth; /* what the array can hold */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274 atomic_t refcnt; /* map can be shared */
275};
276
277struct request_queue
278{
279 /*
280 * Together with queue_head for cacheline sharing
281 */
282 struct list_head queue_head;
283 struct request *last_merge;
284 elevator_t *elevator;
285
286 /*
287 * the queue request freelist, one for reads and one for writes
288 */
289 struct request_list rq;
290
291 request_fn_proc *request_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292 make_request_fn *make_request_fn;
293 prep_rq_fn *prep_rq_fn;
294 unplug_fn *unplug_fn;
295 merge_bvec_fn *merge_bvec_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296 prepare_flush_fn *prepare_flush_fn;
Jens Axboeff856ba2006-01-09 16:02:34 +0100297 softirq_done_fn *softirq_done_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298
299 /*
Tejun Heo8922e162005-10-20 16:23:44 +0200300 * Dispatch queue sorting
301 */
Jens Axboe1b47f532005-10-20 16:37:00 +0200302 sector_t end_sector;
Tejun Heo8922e162005-10-20 16:23:44 +0200303 struct request *boundary_rq;
Tejun Heo8922e162005-10-20 16:23:44 +0200304
305 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306 * Auto-unplugging state
307 */
308 struct timer_list unplug_timer;
309 int unplug_thresh; /* After this many requests */
310 unsigned long unplug_delay; /* After this many jiffies */
311 struct work_struct unplug_work;
312
313 struct backing_dev_info backing_dev_info;
314
315 /*
316 * The queue owner gets to use this for whatever they like.
317 * ll_rw_blk doesn't touch it.
318 */
319 void *queuedata;
320
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321 /*
322 * queue needs bounce pages for pages above this limit
323 */
324 unsigned long bounce_pfn;
Al Viro8267e262005-10-21 03:20:53 -0400325 gfp_t bounce_gfp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326
327 /*
328 * various queue flags, see QUEUE_* below
329 */
330 unsigned long queue_flags;
331
332 /*
152587d2005-04-12 16:22:06 -0500333 * protects queue structures from reentrancy. ->__queue_lock should
334 * _never_ be used directly, it is queue private. always use
335 * ->queue_lock.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336 */
152587d2005-04-12 16:22:06 -0500337 spinlock_t __queue_lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338 spinlock_t *queue_lock;
339
340 /*
341 * queue kobject
342 */
343 struct kobject kobj;
344
345 /*
346 * queue settings
347 */
348 unsigned long nr_requests; /* Max # of requests */
349 unsigned int nr_congestion_on;
350 unsigned int nr_congestion_off;
351 unsigned int nr_batching;
352
Jens Axboe2cb2e142006-01-17 09:04:32 +0100353 unsigned int max_sectors;
354 unsigned int max_hw_sectors;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700355 unsigned short max_phys_segments;
356 unsigned short max_hw_segments;
357 unsigned short hardsect_size;
358 unsigned int max_segment_size;
359
360 unsigned long seg_boundary_mask;
James Bottomleyfa0ccd82008-01-10 11:30:36 -0600361 void *dma_drain_buffer;
362 unsigned int dma_drain_size;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363 unsigned int dma_alignment;
364
365 struct blk_queue_tag *queue_tags;
Jens Axboe6eca9002007-10-25 10:14:47 +0200366 struct list_head tag_busy_list;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700367
Tejun Heo15853af2005-11-10 08:52:05 +0100368 unsigned int nr_sorted;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369 unsigned int in_flight;
370
371 /*
372 * sg stuff
373 */
374 unsigned int sg_timeout;
375 unsigned int sg_reserved_size;
Christoph Lameter19460892005-06-23 00:08:19 -0700376 int node;
Alexey Dobriyan6c5c9342006-09-29 01:59:40 -0700377#ifdef CONFIG_BLK_DEV_IO_TRACE
Jens Axboe2056a782006-03-23 20:00:26 +0100378 struct blk_trace *blk_trace;
Alexey Dobriyan6c5c9342006-09-29 01:59:40 -0700379#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380 /*
381 * reserved for flush operations
382 */
Tejun Heo797e7db2006-01-06 09:51:03 +0100383 unsigned int ordered, next_ordered, ordseq;
384 int orderr, ordcolor;
385 struct request pre_flush_rq, bar_rq, post_flush_rq;
386 struct request *orig_bar_rq;
Al Viro483f4af2006-03-18 18:34:37 -0500387
388 struct mutex sysfs_lock;
FUJITA Tomonorid351af02007-07-09 12:40:35 +0200389
390#if defined(CONFIG_BLK_DEV_BSG)
391 struct bsg_class_device bsg_dev;
392#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700393};
394
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395#define QUEUE_FLAG_CLUSTER 0 /* cluster several segments into 1 */
396#define QUEUE_FLAG_QUEUED 1 /* uses generic tag queueing */
397#define QUEUE_FLAG_STOPPED 2 /* queue is stopped */
Qi Yong4e971822007-07-25 08:45:51 +0200398#define QUEUE_FLAG_READFULL 3 /* read queue has been filled */
399#define QUEUE_FLAG_WRITEFULL 4 /* write queue has been filled */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700400#define QUEUE_FLAG_DEAD 5 /* queue being torn down */
401#define QUEUE_FLAG_REENTER 6 /* Re-entrancy avoidance */
402#define QUEUE_FLAG_PLUGGED 7 /* queue is plugged */
Jens Axboe64521d12005-10-28 08:30:39 +0200403#define QUEUE_FLAG_ELVSWITCH 8 /* don't use elevator, just do FIFO */
FUJITA Tomonoriabae1fd2007-07-16 08:52:14 +0200404#define QUEUE_FLAG_BIDI 9 /* queue supports bidi requests */
Tejun Heo797e7db2006-01-06 09:51:03 +0100405
406enum {
407 /*
408 * Hardbarrier is supported with one of the following methods.
409 *
410 * NONE : hardbarrier unsupported
411 * DRAIN : ordering by draining is enough
412 * DRAIN_FLUSH : ordering by draining w/ pre and post flushes
413 * DRAIN_FUA : ordering by draining w/ pre flush and FUA write
414 * TAG : ordering by tag is enough
415 * TAG_FLUSH : ordering by tag w/ pre and post flushes
416 * TAG_FUA : ordering by tag w/ pre flush and FUA write
417 */
418 QUEUE_ORDERED_NONE = 0x00,
419 QUEUE_ORDERED_DRAIN = 0x01,
420 QUEUE_ORDERED_TAG = 0x02,
421
422 QUEUE_ORDERED_PREFLUSH = 0x10,
423 QUEUE_ORDERED_POSTFLUSH = 0x20,
424 QUEUE_ORDERED_FUA = 0x40,
425
426 QUEUE_ORDERED_DRAIN_FLUSH = QUEUE_ORDERED_DRAIN |
427 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
428 QUEUE_ORDERED_DRAIN_FUA = QUEUE_ORDERED_DRAIN |
429 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
430 QUEUE_ORDERED_TAG_FLUSH = QUEUE_ORDERED_TAG |
431 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
432 QUEUE_ORDERED_TAG_FUA = QUEUE_ORDERED_TAG |
433 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
434
435 /*
436 * Ordered operation sequence
437 */
438 QUEUE_ORDSEQ_STARTED = 0x01, /* flushing in progress */
439 QUEUE_ORDSEQ_DRAIN = 0x02, /* waiting for the queue to be drained */
440 QUEUE_ORDSEQ_PREFLUSH = 0x04, /* pre-flushing in progress */
441 QUEUE_ORDSEQ_BAR = 0x08, /* original barrier req in progress */
442 QUEUE_ORDSEQ_POSTFLUSH = 0x10, /* post-flushing in progress */
443 QUEUE_ORDSEQ_DONE = 0x20,
444};
Linus Torvalds1da177e2005-04-16 15:20:36 -0700445
446#define blk_queue_plugged(q) test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
447#define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
448#define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
Tejun Heo797e7db2006-01-06 09:51:03 +0100449#define blk_queue_flushing(q) ((q)->ordseq)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450
Jens Axboe4aff5e22006-08-10 08:44:47 +0200451#define blk_fs_request(rq) ((rq)->cmd_type == REQ_TYPE_FS)
452#define blk_pc_request(rq) ((rq)->cmd_type == REQ_TYPE_BLOCK_PC)
453#define blk_special_request(rq) ((rq)->cmd_type == REQ_TYPE_SPECIAL)
454#define blk_sense_request(rq) ((rq)->cmd_type == REQ_TYPE_SENSE)
455
456#define blk_noretry_request(rq) ((rq)->cmd_flags & REQ_FAILFAST)
457#define blk_rq_started(rq) ((rq)->cmd_flags & REQ_STARTED)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458
459#define blk_account_rq(rq) (blk_rq_started(rq) && blk_fs_request(rq))
460
Jens Axboe4aff5e22006-08-10 08:44:47 +0200461#define blk_pm_suspend_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND)
462#define blk_pm_resume_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_RESUME)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700463#define blk_pm_request(rq) \
Jens Axboe4aff5e22006-08-10 08:44:47 +0200464 (blk_pm_suspend_request(rq) || blk_pm_resume_request(rq))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700465
Jens Axboe4aff5e22006-08-10 08:44:47 +0200466#define blk_sorted_rq(rq) ((rq)->cmd_flags & REQ_SORTED)
467#define blk_barrier_rq(rq) ((rq)->cmd_flags & REQ_HARDBARRIER)
468#define blk_fua_rq(rq) ((rq)->cmd_flags & REQ_FUA)
FUJITA Tomonoriabae1fd2007-07-16 08:52:14 +0200469#define blk_bidi_rq(rq) ((rq)->next_rq != NULL)
Jens Axboebf2de6f2007-09-27 13:01:25 +0200470#define blk_empty_barrier(rq) (blk_barrier_rq(rq) && blk_fs_request(rq) && !(rq)->hard_nr_sectors)
Kiyoshi Ueda336cdb42007-12-11 17:40:30 -0500471/* rq->queuelist of dequeued request must be list_empty() */
472#define blk_queued_rq(rq) (!list_empty(&(rq)->queuelist))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700473
474#define list_entry_rq(ptr) list_entry((ptr), struct request, queuelist)
475
Jens Axboe4aff5e22006-08-10 08:44:47 +0200476#define rq_data_dir(rq) ((rq)->cmd_flags & 1)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700477
Jens Axboe9e2585a2006-07-28 09:26:13 +0200478/*
479 * We regard a request as sync, if it's a READ or a SYNC write.
480 */
481#define rq_is_sync(rq) (rq_data_dir((rq)) == READ || (rq)->cmd_flags & REQ_RW_SYNC)
Jens Axboe5404bc72006-08-10 09:01:02 +0200482#define rq_is_meta(rq) ((rq)->cmd_flags & REQ_RW_META)
Jens Axboe9e2585a2006-07-28 09:26:13 +0200483
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484static inline int blk_queue_full(struct request_queue *q, int rw)
485{
486 if (rw == READ)
487 return test_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
488 return test_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
489}
490
491static inline void blk_set_queue_full(struct request_queue *q, int rw)
492{
493 if (rw == READ)
494 set_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
495 else
496 set_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
497}
498
499static inline void blk_clear_queue_full(struct request_queue *q, int rw)
500{
501 if (rw == READ)
502 clear_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
503 else
504 clear_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
505}
506
507
508/*
509 * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
510 * it already be started by driver.
511 */
512#define RQ_NOMERGE_FLAGS \
513 (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER)
514#define rq_mergeable(rq) \
Jens Axboe4aff5e22006-08-10 08:44:47 +0200515 (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && blk_fs_request((rq)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700516
517/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700518 * q->prep_rq_fn return values
519 */
520#define BLKPREP_OK 0 /* serve it */
521#define BLKPREP_KILL 1 /* fatal error, kill */
522#define BLKPREP_DEFER 2 /* leave on queue */
523
524extern unsigned long blk_max_low_pfn, blk_max_pfn;
525
526/*
527 * standard bounce addresses:
528 *
529 * BLK_BOUNCE_HIGH : bounce all highmem pages
530 * BLK_BOUNCE_ANY : don't bounce anything
531 * BLK_BOUNCE_ISA : bounce pages above ISA DMA boundary
532 */
533#define BLK_BOUNCE_HIGH ((u64)blk_max_low_pfn << PAGE_SHIFT)
534#define BLK_BOUNCE_ANY ((u64)blk_max_pfn << PAGE_SHIFT)
535#define BLK_BOUNCE_ISA (ISA_DMA_THRESHOLD)
536
Jens Axboe3d6392c2007-07-09 12:38:05 +0200537/*
538 * default timeout for SG_IO if none specified
539 */
540#define BLK_DEFAULT_SG_TIMEOUT (60 * HZ)
541
Christoph Lameter2a7326b2007-07-17 04:03:37 -0700542#ifdef CONFIG_BOUNCE
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543extern int init_emergency_isa_pool(void);
Jens Axboe165125e2007-07-24 09:28:11 +0200544extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700545#else
546static inline int init_emergency_isa_pool(void)
547{
548 return 0;
549}
Jens Axboe165125e2007-07-24 09:28:11 +0200550static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551{
552}
553#endif /* CONFIG_MMU */
554
NeilBrown5705f702007-09-25 12:35:59 +0200555struct req_iterator {
556 int i;
557 struct bio *bio;
558};
559
560/* This should not be used directly - use rq_for_each_segment */
561#define __rq_for_each_bio(_bio, rq) \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562 if ((rq->bio)) \
563 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
564
NeilBrown5705f702007-09-25 12:35:59 +0200565#define rq_for_each_segment(bvl, _rq, _iter) \
566 __rq_for_each_bio(_iter.bio, _rq) \
567 bio_for_each_segment(bvl, _iter.bio, _iter.i)
568
569#define rq_iter_last(rq, _iter) \
570 (_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)
571
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572extern int blk_register_queue(struct gendisk *disk);
573extern void blk_unregister_queue(struct gendisk *disk);
574extern void register_disk(struct gendisk *dev);
575extern void generic_make_request(struct bio *bio);
576extern void blk_put_request(struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +0200577extern void __blk_put_request(struct request_queue *, struct request *);
Tejun Heo8ffdc652006-01-06 09:49:03 +0100578extern void blk_end_sync_rq(struct request *rq, int error);
Jens Axboe165125e2007-07-24 09:28:11 +0200579extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
580extern void blk_insert_request(struct request_queue *, struct request *, int, void *);
581extern void blk_requeue_request(struct request_queue *, struct request *);
582extern void blk_plug_device(struct request_queue *);
583extern int blk_remove_plug(struct request_queue *);
584extern void blk_recount_segments(struct request_queue *, struct bio *);
FUJITA Tomonori45e79a32007-07-09 12:39:20 +0200585extern int scsi_cmd_ioctl(struct file *, struct request_queue *,
586 struct gendisk *, unsigned int, void __user *);
Christoph Hellwig21b2f0c2006-03-22 17:52:04 +0100587extern int sg_scsi_ioctl(struct file *, struct request_queue *,
588 struct gendisk *, struct scsi_ioctl_command __user *);
Andrew Morton3fcfab12006-10-19 23:28:16 -0700589
590/*
Jens Axboe1aa4f242006-12-19 08:33:11 +0100591 * Temporary export, until SCSI gets fixed up.
592 */
NeilBrown3001ca72007-08-16 13:31:27 +0200593extern int blk_rq_append_bio(struct request_queue *q, struct request *rq,
594 struct bio *bio);
Jens Axboe1aa4f242006-12-19 08:33:11 +0100595
596/*
Andrew Morton3fcfab12006-10-19 23:28:16 -0700597 * A queue has just exitted congestion. Note this in the global counter of
598 * congested queues, and wake up anyone who was waiting for requests to be
599 * put back.
600 */
Jens Axboe165125e2007-07-24 09:28:11 +0200601static inline void blk_clear_queue_congested(struct request_queue *q, int rw)
Andrew Morton3fcfab12006-10-19 23:28:16 -0700602{
603 clear_bdi_congested(&q->backing_dev_info, rw);
604}
605
606/*
607 * A queue has just entered congestion. Flag that in the queue's VM-visible
608 * state flags and increment the global gounter of congested queues.
609 */
Jens Axboe165125e2007-07-24 09:28:11 +0200610static inline void blk_set_queue_congested(struct request_queue *q, int rw)
Andrew Morton3fcfab12006-10-19 23:28:16 -0700611{
612 set_bdi_congested(&q->backing_dev_info, rw);
613}
614
Jens Axboe165125e2007-07-24 09:28:11 +0200615extern void blk_start_queue(struct request_queue *q);
616extern void blk_stop_queue(struct request_queue *q);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700617extern void blk_sync_queue(struct request_queue *q);
Jens Axboe165125e2007-07-24 09:28:11 +0200618extern void __blk_stop_queue(struct request_queue *q);
619extern void blk_run_queue(struct request_queue *);
620extern void blk_start_queueing(struct request_queue *);
621extern int blk_rq_map_user(struct request_queue *, struct request *, void __user *, unsigned long);
Jens Axboe8e5cfc42006-12-19 11:12:46 +0100622extern int blk_rq_unmap_user(struct bio *);
Jens Axboe165125e2007-07-24 09:28:11 +0200623extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
624extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
Mike Christie0e75f902006-12-01 10:40:55 +0100625 struct sg_iovec *, int, unsigned int);
Jens Axboe165125e2007-07-24 09:28:11 +0200626extern int blk_execute_rq(struct request_queue *, struct gendisk *,
James Bottomley 994ca9a2005-06-20 14:11:09 +0200627 struct request *, int);
Jens Axboe165125e2007-07-24 09:28:11 +0200628extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
Jens Axboe15fc8582006-01-06 10:00:50 +0100629 struct request *, int, rq_end_io_fn *);
FUJITA Tomonori337ad412006-12-20 11:18:54 +0100630extern int blk_verify_command(unsigned char *, int);
Alan D. Brunelle2ad8b1e2007-11-07 14:26:56 -0500631extern void blk_unplug(struct request_queue *q);
Mike Christie6e39b692005-11-11 05:30:24 -0600632
Jens Axboe165125e2007-07-24 09:28:11 +0200633static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700634{
635 return bdev->bd_disk->queue;
636}
637
638static inline void blk_run_backing_dev(struct backing_dev_info *bdi,
639 struct page *page)
640{
641 if (bdi && bdi->unplug_io_fn)
642 bdi->unplug_io_fn(bdi, page);
643}
644
645static inline void blk_run_address_space(struct address_space *mapping)
646{
647 if (mapping)
648 blk_run_backing_dev(mapping->backing_dev_info, NULL);
649}
650
651/*
Kiyoshi Ueda3bcddea2007-12-11 17:52:28 -0500652 * blk_end_request() and friends.
653 * __blk_end_request() and end_request() must be called with
654 * the request queue spinlock acquired.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655 *
656 * Several drivers define their own end_request and call
Kiyoshi Ueda3bcddea2007-12-11 17:52:28 -0500657 * blk_end_request() for parts of the original function.
658 * This prevents code duplication in drivers.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659 */
Jens Axboe22b13212008-01-31 12:36:19 +0100660extern int blk_end_request(struct request *rq, int error,
661 unsigned int nr_bytes);
662extern int __blk_end_request(struct request *rq, int error,
663 unsigned int nr_bytes);
664extern int blk_end_bidi_request(struct request *rq, int error,
665 unsigned int nr_bytes, unsigned int bidi_bytes);
Jens Axboea0cd1282007-09-21 10:41:07 +0200666extern void end_request(struct request *, int);
667extern void end_queued_request(struct request *, int);
668extern void end_dequeued_request(struct request *, int);
Jens Axboe22b13212008-01-31 12:36:19 +0100669extern int blk_end_request_callback(struct request *rq, int error,
670 unsigned int nr_bytes,
671 int (drv_callback)(struct request *));
Jens Axboeff856ba2006-01-09 16:02:34 +0100672extern void blk_complete_request(struct request *);
673
Linus Torvalds1da177e2005-04-16 15:20:36 -0700674/*
Kiyoshi Ueda3b113132007-12-11 17:41:17 -0500675 * blk_end_request() takes bytes instead of sectors as a complete size.
676 * blk_rq_bytes() returns bytes left to complete in the entire request.
677 * blk_rq_cur_bytes() returns bytes left to complete in the current segment.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700678 */
Kiyoshi Ueda3b113132007-12-11 17:41:17 -0500679extern unsigned int blk_rq_bytes(struct request *rq);
680extern unsigned int blk_rq_cur_bytes(struct request *rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700681
682static inline void blkdev_dequeue_request(struct request *req)
683{
Tejun Heo8922e162005-10-20 16:23:44 +0200684 elv_dequeue_request(req->q, req);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700685}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700686
Linus Torvalds1da177e2005-04-16 15:20:36 -0700687/*
688 * Access functions for manipulating queue properties
689 */
Jens Axboe165125e2007-07-24 09:28:11 +0200690extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
Christoph Lameter19460892005-06-23 00:08:19 -0700691 spinlock_t *lock, int node_id);
Jens Axboe165125e2007-07-24 09:28:11 +0200692extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
693extern void blk_cleanup_queue(struct request_queue *);
694extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
695extern void blk_queue_bounce_limit(struct request_queue *, u64);
696extern void blk_queue_max_sectors(struct request_queue *, unsigned int);
697extern void blk_queue_max_phys_segments(struct request_queue *, unsigned short);
698extern void blk_queue_max_hw_segments(struct request_queue *, unsigned short);
699extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
700extern void blk_queue_hardsect_size(struct request_queue *, unsigned short);
701extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
James Bottomleyfa0ccd82008-01-10 11:30:36 -0600702extern int blk_queue_dma_drain(struct request_queue *q, void *buf,
703 unsigned int size);
Jens Axboe165125e2007-07-24 09:28:11 +0200704extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
705extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
706extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
707extern void blk_queue_dma_alignment(struct request_queue *, int);
James Bottomley11c3e682007-12-31 16:37:00 -0600708extern void blk_queue_update_dma_alignment(struct request_queue *, int);
Jens Axboe165125e2007-07-24 09:28:11 +0200709extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700710extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
Jens Axboe165125e2007-07-24 09:28:11 +0200711extern int blk_queue_ordered(struct request_queue *, unsigned, prepare_flush_fn *);
Jens Axboe165125e2007-07-24 09:28:11 +0200712extern int blk_do_ordered(struct request_queue *, struct request **);
713extern unsigned blk_ordered_cur_seq(struct request_queue *);
Tejun Heo797e7db2006-01-06 09:51:03 +0100714extern unsigned blk_ordered_req_seq(struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +0200715extern void blk_ordered_complete_seq(struct request_queue *, unsigned, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700716
Jens Axboe165125e2007-07-24 09:28:11 +0200717extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700718extern void blk_dump_rq_flags(struct request *, char *);
Jens Axboe165125e2007-07-24 09:28:11 +0200719extern void generic_unplug_device(struct request_queue *);
720extern void __generic_unplug_device(struct request_queue *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700721extern long nr_blockdev_pages(void);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700722
Jens Axboe165125e2007-07-24 09:28:11 +0200723int blk_get_queue(struct request_queue *);
724struct request_queue *blk_alloc_queue(gfp_t);
725struct request_queue *blk_alloc_queue_node(gfp_t, int);
726extern void blk_put_queue(struct request_queue *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727
728/*
729 * tag stuff
730 */
731#define blk_queue_tag_depth(q) ((q)->queue_tags->busy)
732#define blk_queue_tag_queue(q) ((q)->queue_tags->busy < (q)->queue_tags->max_depth)
Jens Axboe4aff5e22006-08-10 08:44:47 +0200733#define blk_rq_tagged(rq) ((rq)->cmd_flags & REQ_QUEUED)
Jens Axboe165125e2007-07-24 09:28:11 +0200734extern int blk_queue_start_tag(struct request_queue *, struct request *);
735extern struct request *blk_queue_find_tag(struct request_queue *, int);
736extern void blk_queue_end_tag(struct request_queue *, struct request *);
737extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *);
738extern void blk_queue_free_tags(struct request_queue *);
739extern int blk_queue_resize_tags(struct request_queue *, int);
740extern void blk_queue_invalidate_tags(struct request_queue *);
James Bottomley492dfb42006-08-30 15:48:45 -0400741extern struct blk_queue_tag *blk_init_tags(int);
742extern void blk_free_tags(struct blk_queue_tag *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743
David C Somayajuluf583f492006-10-04 08:27:25 +0200744static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
745 int tag)
746{
747 if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
748 return NULL;
749 return bqt->tag_index[tag];
750}
751
Linus Torvalds1da177e2005-04-16 15:20:36 -0700752extern int blkdev_issue_flush(struct block_device *, sector_t *);
753
754#define MAX_PHYS_SEGMENTS 128
755#define MAX_HW_SEGMENTS 128
Mike Christiedefd94b2005-12-05 02:37:06 -0600756#define SAFE_MAX_SECTORS 255
757#define BLK_DEF_MAX_SECTORS 1024
Linus Torvalds1da177e2005-04-16 15:20:36 -0700758
759#define MAX_SEGMENT_SIZE 65536
760
761#define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
762
Jens Axboe165125e2007-07-24 09:28:11 +0200763static inline int queue_hardsect_size(struct request_queue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700764{
765 int retval = 512;
766
767 if (q && q->hardsect_size)
768 retval = q->hardsect_size;
769
770 return retval;
771}
772
773static inline int bdev_hardsect_size(struct block_device *bdev)
774{
775 return queue_hardsect_size(bdev_get_queue(bdev));
776}
777
Jens Axboe165125e2007-07-24 09:28:11 +0200778static inline int queue_dma_alignment(struct request_queue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779{
Pete Wyckoff482eb682008-01-01 10:23:02 -0500780 return q ? q->dma_alignment : 511;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700781}
782
Linus Torvalds1da177e2005-04-16 15:20:36 -0700783/* assumes size > 256 */
784static inline unsigned int blksize_bits(unsigned int size)
785{
786 unsigned int bits = 8;
787 do {
788 bits++;
789 size >>= 1;
790 } while (size > 256);
791 return bits;
792}
793
Adrian Bunk2befb9e2005-09-10 00:27:17 -0700794static inline unsigned int block_size(struct block_device *bdev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700795{
796 return bdev->bd_block_size;
797}
798
799typedef struct {struct page *v;} Sector;
800
801unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
802
803static inline void put_dev_sector(Sector p)
804{
805 page_cache_release(p.v);
806}
807
808struct work_struct;
809int kblockd_schedule_work(struct work_struct *work);
Andrew Morton19a75d82007-05-09 02:33:56 -0700810void kblockd_flush_work(struct work_struct *work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700811
Linus Torvalds1da177e2005-04-16 15:20:36 -0700812#define MODULE_ALIAS_BLOCKDEV(major,minor) \
813 MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
814#define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
815 MODULE_ALIAS("block-major-" __stringify(major) "-*")
816
817
David Howells93614012006-09-30 20:45:40 +0200818#else /* CONFIG_BLOCK */
819/*
820 * stubs for when the block layer is configured out
821 */
822#define buffer_heads_over_limit 0
823
David Howells93614012006-09-30 20:45:40 +0200824static inline long nr_blockdev_pages(void)
825{
826 return 0;
827}
828
Andrew Mortonbcfd8d32006-08-31 12:56:06 +0200829static inline void exit_io_context(void)
830{
831}
David Howells93614012006-09-30 20:45:40 +0200832
Jens Axboe023ccde2008-01-29 14:08:06 +0100833struct io_context;
Jens Axboefd0928d2008-01-24 08:52:45 +0100834static inline int put_io_context(struct io_context *ioc)
835{
836 return 1;
837}
838
839
David Howells93614012006-09-30 20:45:40 +0200840#endif /* CONFIG_BLOCK */
841
Linus Torvalds1da177e2005-04-16 15:20:36 -0700842#endif