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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
219 unsigned int data_len;
FUJITA Tomonori7a85f882008-03-04 11:17:11 +0100220 unsigned int extra_len; /* length of alignment and padding */
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 *);
Tejun Heo2fb98e82008-02-19 11:36:53 +0100262typedef int (dma_drain_needed_fn)(struct request *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263
264enum blk_queue_state {
265 Queue_down,
266 Queue_up,
267};
268
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269struct blk_queue_tag {
270 struct request **tag_index; /* map of busy tags */
271 unsigned long *tag_map; /* bit map of free/busy tags */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272 int busy; /* current depth */
273 int max_depth; /* what we will send to device */
Tejun Heoba025082005-08-05 13:28:11 -0700274 int real_max_depth; /* what the array can hold */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275 atomic_t refcnt; /* map can be shared */
276};
277
278struct request_queue
279{
280 /*
281 * Together with queue_head for cacheline sharing
282 */
283 struct list_head queue_head;
284 struct request *last_merge;
285 elevator_t *elevator;
286
287 /*
288 * the queue request freelist, one for reads and one for writes
289 */
290 struct request_list rq;
291
292 request_fn_proc *request_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293 make_request_fn *make_request_fn;
294 prep_rq_fn *prep_rq_fn;
295 unplug_fn *unplug_fn;
296 merge_bvec_fn *merge_bvec_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297 prepare_flush_fn *prepare_flush_fn;
Jens Axboeff856ba2006-01-09 16:02:34 +0100298 softirq_done_fn *softirq_done_fn;
Tejun Heo2fb98e82008-02-19 11:36:53 +0100299 dma_drain_needed_fn *dma_drain_needed;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300
301 /*
Tejun Heo8922e162005-10-20 16:23:44 +0200302 * Dispatch queue sorting
303 */
Jens Axboe1b47f532005-10-20 16:37:00 +0200304 sector_t end_sector;
Tejun Heo8922e162005-10-20 16:23:44 +0200305 struct request *boundary_rq;
Tejun Heo8922e162005-10-20 16:23:44 +0200306
307 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308 * Auto-unplugging state
309 */
310 struct timer_list unplug_timer;
311 int unplug_thresh; /* After this many requests */
312 unsigned long unplug_delay; /* After this many jiffies */
313 struct work_struct unplug_work;
314
315 struct backing_dev_info backing_dev_info;
316
317 /*
318 * The queue owner gets to use this for whatever they like.
319 * ll_rw_blk doesn't touch it.
320 */
321 void *queuedata;
322
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323 /*
324 * queue needs bounce pages for pages above this limit
325 */
326 unsigned long bounce_pfn;
Al Viro8267e262005-10-21 03:20:53 -0400327 gfp_t bounce_gfp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700328
329 /*
330 * various queue flags, see QUEUE_* below
331 */
332 unsigned long queue_flags;
333
334 /*
152587d2005-04-12 16:22:06 -0500335 * protects queue structures from reentrancy. ->__queue_lock should
336 * _never_ be used directly, it is queue private. always use
337 * ->queue_lock.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338 */
152587d2005-04-12 16:22:06 -0500339 spinlock_t __queue_lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340 spinlock_t *queue_lock;
341
342 /*
343 * queue kobject
344 */
345 struct kobject kobj;
346
347 /*
348 * queue settings
349 */
350 unsigned long nr_requests; /* Max # of requests */
351 unsigned int nr_congestion_on;
352 unsigned int nr_congestion_off;
353 unsigned int nr_batching;
354
Jens Axboe2cb2e142006-01-17 09:04:32 +0100355 unsigned int max_sectors;
356 unsigned int max_hw_sectors;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357 unsigned short max_phys_segments;
358 unsigned short max_hw_segments;
359 unsigned short hardsect_size;
360 unsigned int max_segment_size;
361
362 unsigned long seg_boundary_mask;
James Bottomleyfa0ccd82008-01-10 11:30:36 -0600363 void *dma_drain_buffer;
364 unsigned int dma_drain_size;
Tejun Heoe3790c72008-03-04 11:18:17 +0100365 unsigned int dma_pad_mask;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366 unsigned int dma_alignment;
367
368 struct blk_queue_tag *queue_tags;
Jens Axboe6eca9002007-10-25 10:14:47 +0200369 struct list_head tag_busy_list;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370
Tejun Heo15853af2005-11-10 08:52:05 +0100371 unsigned int nr_sorted;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372 unsigned int in_flight;
373
374 /*
375 * sg stuff
376 */
377 unsigned int sg_timeout;
378 unsigned int sg_reserved_size;
Christoph Lameter19460892005-06-23 00:08:19 -0700379 int node;
Alexey Dobriyan6c5c9342006-09-29 01:59:40 -0700380#ifdef CONFIG_BLK_DEV_IO_TRACE
Jens Axboe2056a782006-03-23 20:00:26 +0100381 struct blk_trace *blk_trace;
Alexey Dobriyan6c5c9342006-09-29 01:59:40 -0700382#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383 /*
384 * reserved for flush operations
385 */
Tejun Heo797e7db2006-01-06 09:51:03 +0100386 unsigned int ordered, next_ordered, ordseq;
387 int orderr, ordcolor;
388 struct request pre_flush_rq, bar_rq, post_flush_rq;
389 struct request *orig_bar_rq;
Al Viro483f4af2006-03-18 18:34:37 -0500390
391 struct mutex sysfs_lock;
FUJITA Tomonorid351af02007-07-09 12:40:35 +0200392
393#if defined(CONFIG_BLK_DEV_BSG)
394 struct bsg_class_device bsg_dev;
395#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700396};
397
Linus Torvalds1da177e2005-04-16 15:20:36 -0700398#define QUEUE_FLAG_CLUSTER 0 /* cluster several segments into 1 */
399#define QUEUE_FLAG_QUEUED 1 /* uses generic tag queueing */
400#define QUEUE_FLAG_STOPPED 2 /* queue is stopped */
Qi Yong4e971822007-07-25 08:45:51 +0200401#define QUEUE_FLAG_READFULL 3 /* read queue has been filled */
402#define QUEUE_FLAG_WRITEFULL 4 /* write queue has been filled */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403#define QUEUE_FLAG_DEAD 5 /* queue being torn down */
404#define QUEUE_FLAG_REENTER 6 /* Re-entrancy avoidance */
405#define QUEUE_FLAG_PLUGGED 7 /* queue is plugged */
Jens Axboe64521d12005-10-28 08:30:39 +0200406#define QUEUE_FLAG_ELVSWITCH 8 /* don't use elevator, just do FIFO */
FUJITA Tomonoriabae1fd2007-07-16 08:52:14 +0200407#define QUEUE_FLAG_BIDI 9 /* queue supports bidi requests */
Tejun Heo797e7db2006-01-06 09:51:03 +0100408
409enum {
410 /*
411 * Hardbarrier is supported with one of the following methods.
412 *
413 * NONE : hardbarrier unsupported
414 * DRAIN : ordering by draining is enough
415 * DRAIN_FLUSH : ordering by draining w/ pre and post flushes
416 * DRAIN_FUA : ordering by draining w/ pre flush and FUA write
417 * TAG : ordering by tag is enough
418 * TAG_FLUSH : ordering by tag w/ pre and post flushes
419 * TAG_FUA : ordering by tag w/ pre flush and FUA write
420 */
421 QUEUE_ORDERED_NONE = 0x00,
422 QUEUE_ORDERED_DRAIN = 0x01,
423 QUEUE_ORDERED_TAG = 0x02,
424
425 QUEUE_ORDERED_PREFLUSH = 0x10,
426 QUEUE_ORDERED_POSTFLUSH = 0x20,
427 QUEUE_ORDERED_FUA = 0x40,
428
429 QUEUE_ORDERED_DRAIN_FLUSH = QUEUE_ORDERED_DRAIN |
430 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
431 QUEUE_ORDERED_DRAIN_FUA = QUEUE_ORDERED_DRAIN |
432 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
433 QUEUE_ORDERED_TAG_FLUSH = QUEUE_ORDERED_TAG |
434 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
435 QUEUE_ORDERED_TAG_FUA = QUEUE_ORDERED_TAG |
436 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
437
438 /*
439 * Ordered operation sequence
440 */
441 QUEUE_ORDSEQ_STARTED = 0x01, /* flushing in progress */
442 QUEUE_ORDSEQ_DRAIN = 0x02, /* waiting for the queue to be drained */
443 QUEUE_ORDSEQ_PREFLUSH = 0x04, /* pre-flushing in progress */
444 QUEUE_ORDSEQ_BAR = 0x08, /* original barrier req in progress */
445 QUEUE_ORDSEQ_POSTFLUSH = 0x10, /* post-flushing in progress */
446 QUEUE_ORDSEQ_DONE = 0x20,
447};
Linus Torvalds1da177e2005-04-16 15:20:36 -0700448
449#define blk_queue_plugged(q) test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
450#define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
451#define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
Tejun Heo797e7db2006-01-06 09:51:03 +0100452#define blk_queue_flushing(q) ((q)->ordseq)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453
Jens Axboe4aff5e22006-08-10 08:44:47 +0200454#define blk_fs_request(rq) ((rq)->cmd_type == REQ_TYPE_FS)
455#define blk_pc_request(rq) ((rq)->cmd_type == REQ_TYPE_BLOCK_PC)
456#define blk_special_request(rq) ((rq)->cmd_type == REQ_TYPE_SPECIAL)
457#define blk_sense_request(rq) ((rq)->cmd_type == REQ_TYPE_SENSE)
458
459#define blk_noretry_request(rq) ((rq)->cmd_flags & REQ_FAILFAST)
460#define blk_rq_started(rq) ((rq)->cmd_flags & REQ_STARTED)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461
462#define blk_account_rq(rq) (blk_rq_started(rq) && blk_fs_request(rq))
463
Jens Axboe4aff5e22006-08-10 08:44:47 +0200464#define blk_pm_suspend_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND)
465#define blk_pm_resume_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_RESUME)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466#define blk_pm_request(rq) \
Jens Axboe4aff5e22006-08-10 08:44:47 +0200467 (blk_pm_suspend_request(rq) || blk_pm_resume_request(rq))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700468
Jens Axboe4aff5e22006-08-10 08:44:47 +0200469#define blk_sorted_rq(rq) ((rq)->cmd_flags & REQ_SORTED)
470#define blk_barrier_rq(rq) ((rq)->cmd_flags & REQ_HARDBARRIER)
471#define blk_fua_rq(rq) ((rq)->cmd_flags & REQ_FUA)
FUJITA Tomonoriabae1fd2007-07-16 08:52:14 +0200472#define blk_bidi_rq(rq) ((rq)->next_rq != NULL)
Jens Axboebf2de6f2007-09-27 13:01:25 +0200473#define blk_empty_barrier(rq) (blk_barrier_rq(rq) && blk_fs_request(rq) && !(rq)->hard_nr_sectors)
Kiyoshi Ueda336cdb42007-12-11 17:40:30 -0500474/* rq->queuelist of dequeued request must be list_empty() */
475#define blk_queued_rq(rq) (!list_empty(&(rq)->queuelist))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700476
477#define list_entry_rq(ptr) list_entry((ptr), struct request, queuelist)
478
Jens Axboe4aff5e22006-08-10 08:44:47 +0200479#define rq_data_dir(rq) ((rq)->cmd_flags & 1)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480
Jens Axboe9e2585a2006-07-28 09:26:13 +0200481/*
482 * We regard a request as sync, if it's a READ or a SYNC write.
483 */
484#define rq_is_sync(rq) (rq_data_dir((rq)) == READ || (rq)->cmd_flags & REQ_RW_SYNC)
Jens Axboe5404bc72006-08-10 09:01:02 +0200485#define rq_is_meta(rq) ((rq)->cmd_flags & REQ_RW_META)
Jens Axboe9e2585a2006-07-28 09:26:13 +0200486
Linus Torvalds1da177e2005-04-16 15:20:36 -0700487static inline int blk_queue_full(struct request_queue *q, int rw)
488{
489 if (rw == READ)
490 return test_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
491 return test_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
492}
493
494static inline void blk_set_queue_full(struct request_queue *q, int rw)
495{
496 if (rw == READ)
497 set_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
498 else
499 set_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
500}
501
502static inline void blk_clear_queue_full(struct request_queue *q, int rw)
503{
504 if (rw == READ)
505 clear_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
506 else
507 clear_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
508}
509
510
511/*
512 * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
513 * it already be started by driver.
514 */
515#define RQ_NOMERGE_FLAGS \
516 (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER)
517#define rq_mergeable(rq) \
Jens Axboe4aff5e22006-08-10 08:44:47 +0200518 (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && blk_fs_request((rq)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700519
520/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700521 * q->prep_rq_fn return values
522 */
523#define BLKPREP_OK 0 /* serve it */
524#define BLKPREP_KILL 1 /* fatal error, kill */
525#define BLKPREP_DEFER 2 /* leave on queue */
526
527extern unsigned long blk_max_low_pfn, blk_max_pfn;
528
529/*
530 * standard bounce addresses:
531 *
532 * BLK_BOUNCE_HIGH : bounce all highmem pages
533 * BLK_BOUNCE_ANY : don't bounce anything
534 * BLK_BOUNCE_ISA : bounce pages above ISA DMA boundary
535 */
536#define BLK_BOUNCE_HIGH ((u64)blk_max_low_pfn << PAGE_SHIFT)
537#define BLK_BOUNCE_ANY ((u64)blk_max_pfn << PAGE_SHIFT)
538#define BLK_BOUNCE_ISA (ISA_DMA_THRESHOLD)
539
Jens Axboe3d6392c2007-07-09 12:38:05 +0200540/*
541 * default timeout for SG_IO if none specified
542 */
543#define BLK_DEFAULT_SG_TIMEOUT (60 * HZ)
544
Christoph Lameter2a7326b2007-07-17 04:03:37 -0700545#ifdef CONFIG_BOUNCE
Linus Torvalds1da177e2005-04-16 15:20:36 -0700546extern int init_emergency_isa_pool(void);
Jens Axboe165125e2007-07-24 09:28:11 +0200547extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548#else
549static inline int init_emergency_isa_pool(void)
550{
551 return 0;
552}
Jens Axboe165125e2007-07-24 09:28:11 +0200553static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700554{
555}
556#endif /* CONFIG_MMU */
557
NeilBrown5705f702007-09-25 12:35:59 +0200558struct req_iterator {
559 int i;
560 struct bio *bio;
561};
562
563/* This should not be used directly - use rq_for_each_segment */
564#define __rq_for_each_bio(_bio, rq) \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565 if ((rq->bio)) \
566 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
567
NeilBrown5705f702007-09-25 12:35:59 +0200568#define rq_for_each_segment(bvl, _rq, _iter) \
569 __rq_for_each_bio(_iter.bio, _rq) \
570 bio_for_each_segment(bvl, _iter.bio, _iter.i)
571
572#define rq_iter_last(rq, _iter) \
573 (_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)
574
Linus Torvalds1da177e2005-04-16 15:20:36 -0700575extern int blk_register_queue(struct gendisk *disk);
576extern void blk_unregister_queue(struct gendisk *disk);
577extern void register_disk(struct gendisk *dev);
578extern void generic_make_request(struct bio *bio);
579extern void blk_put_request(struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +0200580extern void __blk_put_request(struct request_queue *, struct request *);
Tejun Heo8ffdc652006-01-06 09:49:03 +0100581extern void blk_end_sync_rq(struct request *rq, int error);
Jens Axboe165125e2007-07-24 09:28:11 +0200582extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
583extern void blk_insert_request(struct request_queue *, struct request *, int, void *);
584extern void blk_requeue_request(struct request_queue *, struct request *);
585extern void blk_plug_device(struct request_queue *);
586extern int blk_remove_plug(struct request_queue *);
587extern void blk_recount_segments(struct request_queue *, struct bio *);
FUJITA Tomonori45e79a32007-07-09 12:39:20 +0200588extern int scsi_cmd_ioctl(struct file *, struct request_queue *,
589 struct gendisk *, unsigned int, void __user *);
Christoph Hellwig21b2f0c2006-03-22 17:52:04 +0100590extern int sg_scsi_ioctl(struct file *, struct request_queue *,
591 struct gendisk *, struct scsi_ioctl_command __user *);
Andrew Morton3fcfab12006-10-19 23:28:16 -0700592
593/*
Jens Axboe1aa4f242006-12-19 08:33:11 +0100594 * Temporary export, until SCSI gets fixed up.
595 */
NeilBrown3001ca72007-08-16 13:31:27 +0200596extern int blk_rq_append_bio(struct request_queue *q, struct request *rq,
597 struct bio *bio);
Jens Axboe1aa4f242006-12-19 08:33:11 +0100598
599/*
Andrew Morton3fcfab12006-10-19 23:28:16 -0700600 * A queue has just exitted congestion. Note this in the global counter of
601 * congested queues, and wake up anyone who was waiting for requests to be
602 * put back.
603 */
Jens Axboe165125e2007-07-24 09:28:11 +0200604static inline void blk_clear_queue_congested(struct request_queue *q, int rw)
Andrew Morton3fcfab12006-10-19 23:28:16 -0700605{
606 clear_bdi_congested(&q->backing_dev_info, rw);
607}
608
609/*
610 * A queue has just entered congestion. Flag that in the queue's VM-visible
611 * state flags and increment the global gounter of congested queues.
612 */
Jens Axboe165125e2007-07-24 09:28:11 +0200613static inline void blk_set_queue_congested(struct request_queue *q, int rw)
Andrew Morton3fcfab12006-10-19 23:28:16 -0700614{
615 set_bdi_congested(&q->backing_dev_info, rw);
616}
617
Jens Axboe165125e2007-07-24 09:28:11 +0200618extern void blk_start_queue(struct request_queue *q);
619extern void blk_stop_queue(struct request_queue *q);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620extern void blk_sync_queue(struct request_queue *q);
Jens Axboe165125e2007-07-24 09:28:11 +0200621extern void __blk_stop_queue(struct request_queue *q);
622extern void blk_run_queue(struct request_queue *);
623extern void blk_start_queueing(struct request_queue *);
624extern int blk_rq_map_user(struct request_queue *, struct request *, void __user *, unsigned long);
Jens Axboe8e5cfc42006-12-19 11:12:46 +0100625extern int blk_rq_unmap_user(struct bio *);
Jens Axboe165125e2007-07-24 09:28:11 +0200626extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
627extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
Mike Christie0e75f902006-12-01 10:40:55 +0100628 struct sg_iovec *, int, unsigned int);
Jens Axboe165125e2007-07-24 09:28:11 +0200629extern int blk_execute_rq(struct request_queue *, struct gendisk *,
James Bottomley 994ca9a2005-06-20 14:11:09 +0200630 struct request *, int);
Jens Axboe165125e2007-07-24 09:28:11 +0200631extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
Jens Axboe15fc8582006-01-06 10:00:50 +0100632 struct request *, int, rq_end_io_fn *);
FUJITA Tomonori337ad41d2006-12-20 11:18:54 +0100633extern int blk_verify_command(unsigned char *, int);
Alan D. Brunelle2ad8b1e2007-11-07 14:26:56 -0500634extern void blk_unplug(struct request_queue *q);
Mike Christie6e39b69e2005-11-11 05:30:24 -0600635
Jens Axboe165125e2007-07-24 09:28:11 +0200636static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700637{
638 return bdev->bd_disk->queue;
639}
640
641static inline void blk_run_backing_dev(struct backing_dev_info *bdi,
642 struct page *page)
643{
644 if (bdi && bdi->unplug_io_fn)
645 bdi->unplug_io_fn(bdi, page);
646}
647
648static inline void blk_run_address_space(struct address_space *mapping)
649{
650 if (mapping)
651 blk_run_backing_dev(mapping->backing_dev_info, NULL);
652}
653
654/*
Kiyoshi Ueda3bcddea2007-12-11 17:52:28 -0500655 * blk_end_request() and friends.
656 * __blk_end_request() and end_request() must be called with
657 * the request queue spinlock acquired.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700658 *
659 * Several drivers define their own end_request and call
Kiyoshi Ueda3bcddea2007-12-11 17:52:28 -0500660 * blk_end_request() for parts of the original function.
661 * This prevents code duplication in drivers.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700662 */
Jens Axboe22b13212008-01-31 12:36:19 +0100663extern int blk_end_request(struct request *rq, int error,
664 unsigned int nr_bytes);
665extern int __blk_end_request(struct request *rq, int error,
666 unsigned int nr_bytes);
667extern int blk_end_bidi_request(struct request *rq, int error,
668 unsigned int nr_bytes, unsigned int bidi_bytes);
Jens Axboea0cd1282007-09-21 10:41:07 +0200669extern void end_request(struct request *, int);
670extern void end_queued_request(struct request *, int);
671extern void end_dequeued_request(struct request *, int);
Jens Axboe22b13212008-01-31 12:36:19 +0100672extern int blk_end_request_callback(struct request *rq, int error,
673 unsigned int nr_bytes,
674 int (drv_callback)(struct request *));
Jens Axboeff856ba2006-01-09 16:02:34 +0100675extern void blk_complete_request(struct request *);
676
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677/*
Kiyoshi Ueda3b113132007-12-11 17:41:17 -0500678 * blk_end_request() takes bytes instead of sectors as a complete size.
679 * blk_rq_bytes() returns bytes left to complete in the entire request.
680 * blk_rq_cur_bytes() returns bytes left to complete in the current segment.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700681 */
Kiyoshi Ueda3b113132007-12-11 17:41:17 -0500682extern unsigned int blk_rq_bytes(struct request *rq);
683extern unsigned int blk_rq_cur_bytes(struct request *rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700684
685static inline void blkdev_dequeue_request(struct request *req)
686{
Tejun Heo8922e162005-10-20 16:23:44 +0200687 elv_dequeue_request(req->q, req);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700688}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700689
Linus Torvalds1da177e2005-04-16 15:20:36 -0700690/*
691 * Access functions for manipulating queue properties
692 */
Jens Axboe165125e2007-07-24 09:28:11 +0200693extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
Christoph Lameter19460892005-06-23 00:08:19 -0700694 spinlock_t *lock, int node_id);
Jens Axboe165125e2007-07-24 09:28:11 +0200695extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
696extern void blk_cleanup_queue(struct request_queue *);
697extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
698extern void blk_queue_bounce_limit(struct request_queue *, u64);
699extern void blk_queue_max_sectors(struct request_queue *, unsigned int);
700extern void blk_queue_max_phys_segments(struct request_queue *, unsigned short);
701extern void blk_queue_max_hw_segments(struct request_queue *, unsigned short);
702extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
703extern void blk_queue_hardsect_size(struct request_queue *, unsigned short);
704extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
Tejun Heoe3790c72008-03-04 11:18:17 +0100705extern void blk_queue_dma_pad(struct request_queue *, unsigned int);
Tejun Heo2fb98e82008-02-19 11:36:53 +0100706extern int blk_queue_dma_drain(struct request_queue *q,
707 dma_drain_needed_fn *dma_drain_needed,
708 void *buf, unsigned int size);
Jens Axboe165125e2007-07-24 09:28:11 +0200709extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
710extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
711extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
712extern void blk_queue_dma_alignment(struct request_queue *, int);
James Bottomley11c3e682007-12-31 16:37:00 -0600713extern void blk_queue_update_dma_alignment(struct request_queue *, int);
Jens Axboe165125e2007-07-24 09:28:11 +0200714extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700715extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
Jens Axboe165125e2007-07-24 09:28:11 +0200716extern int blk_queue_ordered(struct request_queue *, unsigned, prepare_flush_fn *);
Jens Axboe165125e2007-07-24 09:28:11 +0200717extern int blk_do_ordered(struct request_queue *, struct request **);
718extern unsigned blk_ordered_cur_seq(struct request_queue *);
Tejun Heo797e7db2006-01-06 09:51:03 +0100719extern unsigned blk_ordered_req_seq(struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +0200720extern void blk_ordered_complete_seq(struct request_queue *, unsigned, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700721
Jens Axboe165125e2007-07-24 09:28:11 +0200722extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700723extern void blk_dump_rq_flags(struct request *, char *);
Jens Axboe165125e2007-07-24 09:28:11 +0200724extern void generic_unplug_device(struct request_queue *);
725extern void __generic_unplug_device(struct request_queue *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700726extern long nr_blockdev_pages(void);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727
Jens Axboe165125e2007-07-24 09:28:11 +0200728int blk_get_queue(struct request_queue *);
729struct request_queue *blk_alloc_queue(gfp_t);
730struct request_queue *blk_alloc_queue_node(gfp_t, int);
731extern void blk_put_queue(struct request_queue *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700732
733/*
734 * tag stuff
735 */
736#define blk_queue_tag_depth(q) ((q)->queue_tags->busy)
737#define blk_queue_tag_queue(q) ((q)->queue_tags->busy < (q)->queue_tags->max_depth)
Jens Axboe4aff5e22006-08-10 08:44:47 +0200738#define blk_rq_tagged(rq) ((rq)->cmd_flags & REQ_QUEUED)
Jens Axboe165125e2007-07-24 09:28:11 +0200739extern int blk_queue_start_tag(struct request_queue *, struct request *);
740extern struct request *blk_queue_find_tag(struct request_queue *, int);
741extern void blk_queue_end_tag(struct request_queue *, struct request *);
742extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *);
743extern void blk_queue_free_tags(struct request_queue *);
744extern int blk_queue_resize_tags(struct request_queue *, int);
745extern void blk_queue_invalidate_tags(struct request_queue *);
James Bottomley492dfb42006-08-30 15:48:45 -0400746extern struct blk_queue_tag *blk_init_tags(int);
747extern void blk_free_tags(struct blk_queue_tag *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700748
David C Somayajuluf583f492006-10-04 08:27:25 +0200749static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
750 int tag)
751{
752 if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
753 return NULL;
754 return bqt->tag_index[tag];
755}
756
Linus Torvalds1da177e2005-04-16 15:20:36 -0700757extern int blkdev_issue_flush(struct block_device *, sector_t *);
758
759#define MAX_PHYS_SEGMENTS 128
760#define MAX_HW_SEGMENTS 128
Mike Christiedefd94b2005-12-05 02:37:06 -0600761#define SAFE_MAX_SECTORS 255
762#define BLK_DEF_MAX_SECTORS 1024
Linus Torvalds1da177e2005-04-16 15:20:36 -0700763
764#define MAX_SEGMENT_SIZE 65536
765
766#define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
767
Jens Axboe165125e2007-07-24 09:28:11 +0200768static inline int queue_hardsect_size(struct request_queue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700769{
770 int retval = 512;
771
772 if (q && q->hardsect_size)
773 retval = q->hardsect_size;
774
775 return retval;
776}
777
778static inline int bdev_hardsect_size(struct block_device *bdev)
779{
780 return queue_hardsect_size(bdev_get_queue(bdev));
781}
782
Jens Axboe165125e2007-07-24 09:28:11 +0200783static inline int queue_dma_alignment(struct request_queue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700784{
Pete Wyckoff482eb682008-01-01 10:23:02 -0500785 return q ? q->dma_alignment : 511;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700786}
787
Linus Torvalds1da177e2005-04-16 15:20:36 -0700788/* assumes size > 256 */
789static inline unsigned int blksize_bits(unsigned int size)
790{
791 unsigned int bits = 8;
792 do {
793 bits++;
794 size >>= 1;
795 } while (size > 256);
796 return bits;
797}
798
Adrian Bunk2befb9e2005-09-10 00:27:17 -0700799static inline unsigned int block_size(struct block_device *bdev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700800{
801 return bdev->bd_block_size;
802}
803
804typedef struct {struct page *v;} Sector;
805
806unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
807
808static inline void put_dev_sector(Sector p)
809{
810 page_cache_release(p.v);
811}
812
813struct work_struct;
814int kblockd_schedule_work(struct work_struct *work);
Andrew Morton19a75d82007-05-09 02:33:56 -0700815void kblockd_flush_work(struct work_struct *work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700816
Linus Torvalds1da177e2005-04-16 15:20:36 -0700817#define MODULE_ALIAS_BLOCKDEV(major,minor) \
818 MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
819#define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
820 MODULE_ALIAS("block-major-" __stringify(major) "-*")
821
822
David Howells93614012006-09-30 20:45:40 +0200823#else /* CONFIG_BLOCK */
824/*
825 * stubs for when the block layer is configured out
826 */
827#define buffer_heads_over_limit 0
828
David Howells93614012006-09-30 20:45:40 +0200829static inline long nr_blockdev_pages(void)
830{
831 return 0;
832}
833
Andrew Mortonbcfd8d32006-08-31 12:56:06 +0200834static inline void exit_io_context(void)
835{
836}
David Howells93614012006-09-30 20:45:40 +0200837
Jens Axboe023ccde2008-01-29 14:08:06 +0100838struct io_context;
Jens Axboefd0928d2008-01-24 08:52:45 +0100839static inline int put_io_context(struct io_context *ioc)
840{
841 return 1;
842}
843
844
David Howells93614012006-09-30 20:45:40 +0200845#endif /* CONFIG_BLOCK */
846
Linus Torvalds1da177e2005-04-16 15:20:36 -0700847#endif