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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
37/*
38 * This is the per-process anticipatory I/O scheduler state.
39 */
40struct as_io_context {
41 spinlock_t lock;
42
43 void (*dtor)(struct as_io_context *aic); /* destructor */
44 void (*exit)(struct as_io_context *aic); /* called on task exit */
45
46 unsigned long state;
47 atomic_t nr_queued; /* queued reads & sync writes */
48 atomic_t nr_dispatched; /* number of requests gone to the drivers */
49
50 /* IO History tracking */
51 /* Thinktime */
52 unsigned long last_end_request;
53 unsigned long ttime_total;
54 unsigned long ttime_samples;
55 unsigned long ttime_mean;
56 /* Layout pattern */
57 unsigned int seek_samples;
58 sector_t last_request_pos;
59 u64 seek_total;
60 sector_t seek_mean;
61};
62
63struct cfq_queue;
64struct cfq_io_context {
Jens Axboee2d74ac2006-03-28 08:59:01 +020065 struct rb_node rb_node;
Jens Axboe22e2c502005-06-27 10:55:12 +020066 void *key;
67
Jens Axboee2d74ac2006-03-28 08:59:01 +020068 struct cfq_queue *cfqq[2];
69
Jens Axboe22e2c502005-06-27 10:55:12 +020070 struct io_context *ioc;
71
72 unsigned long last_end_request;
Jens Axboe206dc692006-03-28 13:03:44 +020073 sector_t last_request_pos;
Jens Axboe206dc692006-03-28 13:03:44 +020074
Jens Axboe22e2c502005-06-27 10:55:12 +020075 unsigned long ttime_total;
76 unsigned long ttime_samples;
77 unsigned long ttime_mean;
78
Jens Axboe206dc692006-03-28 13:03:44 +020079 unsigned int seek_samples;
80 u64 seek_total;
81 sector_t seek_mean;
82
Al Virod9ff4182006-03-18 13:51:22 -050083 struct list_head queue_list;
84
Jens Axboee2d74ac2006-03-28 08:59:01 +020085 void (*dtor)(struct io_context *); /* destructor */
86 void (*exit)(struct io_context *); /* called on task exit */
Linus Torvalds1da177e2005-04-16 15:20:36 -070087};
88
89/*
90 * This is the per-process I/O subsystem state. It is refcounted and
91 * kmalloc'ed. Currently all fields are modified in process io context
92 * (apart from the atomic refcount), so require no locking.
93 */
94struct io_context {
95 atomic_t refcount;
Jens Axboe22e2c502005-06-27 10:55:12 +020096 struct task_struct *task;
97
Jens Axboefc463792006-08-29 09:05:44 +020098 unsigned int ioprio_changed;
Linus Torvalds1da177e2005-04-16 15:20:36 -070099
100 /*
101 * For request batching
102 */
103 unsigned long last_waited; /* Time last woken after wait for request */
104 int nr_batch_requests; /* Number of requests left in the batch */
105
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106 struct as_io_context *aic;
Jens Axboee2d74ac2006-03-28 08:59:01 +0200107 struct rb_root cic_root;
Jens Axboe4e521c22007-04-24 21:17:33 +0200108 void *ioc_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109};
110
111void put_io_context(struct io_context *ioc);
112void exit_io_context(void);
Jens Axboeb5deef92006-07-19 23:39:40 +0200113struct io_context *get_io_context(gfp_t gfp_flags, int node);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114void copy_io_context(struct io_context **pdst, struct io_context **psrc);
115void swap_io_context(struct io_context **ioc1, struct io_context **ioc2);
116
117struct request;
Tejun Heo8ffdc652006-01-06 09:49:03 +0100118typedef void (rq_end_io_fn)(struct request *, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119
120struct request_list {
121 int count[2];
122 int starved[2];
Tejun Heocb98fc82005-10-28 08:29:39 +0200123 int elvpriv;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124 mempool_t *rq_pool;
125 wait_queue_head_t wait[2];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126};
127
Jens Axboe4aff5e22006-08-10 08:44:47 +0200128/*
129 * request command types
130 */
131enum rq_cmd_type_bits {
132 REQ_TYPE_FS = 1, /* fs request */
133 REQ_TYPE_BLOCK_PC, /* scsi command */
134 REQ_TYPE_SENSE, /* sense request */
135 REQ_TYPE_PM_SUSPEND, /* suspend request */
136 REQ_TYPE_PM_RESUME, /* resume request */
137 REQ_TYPE_PM_SHUTDOWN, /* shutdown request */
138 REQ_TYPE_FLUSH, /* flush request */
139 REQ_TYPE_SPECIAL, /* driver defined type */
140 REQ_TYPE_LINUX_BLOCK, /* generic block layer message */
141 /*
142 * for ATA/ATAPI devices. this really doesn't belong here, ide should
143 * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver
144 * private REQ_LB opcodes to differentiate what type of request this is
145 */
146 REQ_TYPE_ATA_CMD,
147 REQ_TYPE_ATA_TASK,
148 REQ_TYPE_ATA_TASKFILE,
Jens Axboecea28852006-10-12 15:08:45 +0200149 REQ_TYPE_ATA_PC,
Jens Axboe4aff5e22006-08-10 08:44:47 +0200150};
151
152/*
153 * For request of type REQ_TYPE_LINUX_BLOCK, rq->cmd[0] is the opcode being
154 * sent down (similar to how REQ_TYPE_BLOCK_PC means that ->cmd[] holds a
155 * SCSI cdb.
156 *
157 * 0x00 -> 0x3f are driver private, to be used for whatever purpose they need,
158 * typically to differentiate REQ_TYPE_SPECIAL requests.
159 *
160 */
161enum {
162 /*
163 * just examples for now
164 */
165 REQ_LB_OP_EJECT = 0x40, /* eject request */
166 REQ_LB_OP_FLUSH = 0x41, /* flush device */
167};
168
169/*
170 * request type modified bits. first three bits match BIO_RW* bits, important
171 */
172enum rq_flag_bits {
173 __REQ_RW, /* not set, read. set, write */
174 __REQ_FAILFAST, /* no low level driver retries */
175 __REQ_SORTED, /* elevator knows about this request */
176 __REQ_SOFTBARRIER, /* may not be passed by ioscheduler */
177 __REQ_HARDBARRIER, /* may not be passed by drive either */
178 __REQ_FUA, /* forced unit access */
179 __REQ_NOMERGE, /* don't touch this for merging */
180 __REQ_STARTED, /* drive already may have started this one */
181 __REQ_DONTPREP, /* don't call prep for this one */
182 __REQ_QUEUED, /* uses queueing */
183 __REQ_ELVPRIV, /* elevator private data attached */
184 __REQ_FAILED, /* set if the request failed */
185 __REQ_QUIET, /* don't worry about errors */
186 __REQ_PREEMPT, /* set for "ide_preempt" requests */
187 __REQ_ORDERED_COLOR, /* is before or after barrier */
188 __REQ_RW_SYNC, /* request is sync (O_DIRECT) */
Jens Axboe49171e52006-08-10 08:59:11 +0200189 __REQ_ALLOCED, /* request came from our alloc pool */
Jens Axboe5404bc72006-08-10 09:01:02 +0200190 __REQ_RW_META, /* metadata io request */
Jens Axboe4aff5e22006-08-10 08:44:47 +0200191 __REQ_NR_BITS, /* stops here */
192};
193
194#define REQ_RW (1 << __REQ_RW)
195#define REQ_FAILFAST (1 << __REQ_FAILFAST)
196#define REQ_SORTED (1 << __REQ_SORTED)
197#define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER)
198#define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER)
199#define REQ_FUA (1 << __REQ_FUA)
200#define REQ_NOMERGE (1 << __REQ_NOMERGE)
201#define REQ_STARTED (1 << __REQ_STARTED)
202#define REQ_DONTPREP (1 << __REQ_DONTPREP)
203#define REQ_QUEUED (1 << __REQ_QUEUED)
204#define REQ_ELVPRIV (1 << __REQ_ELVPRIV)
205#define REQ_FAILED (1 << __REQ_FAILED)
206#define REQ_QUIET (1 << __REQ_QUIET)
207#define REQ_PREEMPT (1 << __REQ_PREEMPT)
208#define REQ_ORDERED_COLOR (1 << __REQ_ORDERED_COLOR)
209#define REQ_RW_SYNC (1 << __REQ_RW_SYNC)
Jens Axboe49171e52006-08-10 08:59:11 +0200210#define REQ_ALLOCED (1 << __REQ_ALLOCED)
Jens Axboe5404bc72006-08-10 09:01:02 +0200211#define REQ_RW_META (1 << __REQ_RW_META)
Jens Axboe4aff5e22006-08-10 08:44:47 +0200212
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213#define BLK_MAX_CDB 16
214
215/*
216 * try to put the fields that are referenced together in the same cacheline
217 */
218struct request {
Jens Axboeff856ba2006-01-09 16:02:34 +0100219 struct list_head queuelist;
220 struct list_head donelist;
221
Jens Axboe165125e2007-07-24 09:28:11 +0200222 struct request_queue *q;
Jens Axboee6a1c872006-08-10 09:00:21 +0200223
Jens Axboe4aff5e22006-08-10 08:44:47 +0200224 unsigned int cmd_flags;
225 enum rq_cmd_type_bits cmd_type;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226
227 /* Maintain bio traversal state for part by part I/O submission.
228 * hard_* are block layer internals, no driver should touch them!
229 */
230
231 sector_t sector; /* next sector to submit */
Jens Axboee6a1c872006-08-10 09:00:21 +0200232 sector_t hard_sector; /* next sector to complete */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233 unsigned long nr_sectors; /* no. of sectors left to submit */
Jens Axboee6a1c872006-08-10 09:00:21 +0200234 unsigned long hard_nr_sectors; /* no. of sectors left to complete */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235 /* no. of sectors left to submit in the current segment */
236 unsigned int current_nr_sectors;
237
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238 /* no. of sectors left to complete in the current segment */
239 unsigned int hard_cur_sectors;
240
241 struct bio *bio;
242 struct bio *biotail;
243
Jens Axboe98170642006-07-28 09:23:08 +0200244 struct hlist_node hash; /* merge hash */
Jens Axboee6a1c872006-08-10 09:00:21 +0200245 /*
246 * The rb_node is only used inside the io scheduler, requests
247 * are pruned when moved to the dispatch queue. So let the
248 * completion_data share space with the rb_node.
249 */
250 union {
251 struct rb_node rb_node; /* sort/lookup */
252 void *completion_data;
253 };
Jens Axboe98170642006-07-28 09:23:08 +0200254
Jens Axboeff7d1452006-07-12 14:04:37 +0200255 /*
256 * two pointers are available for the IO schedulers, if they need
257 * more they have to dynamically allocate it.
258 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259 void *elevator_private;
Jens Axboeff7d1452006-07-12 14:04:37 +0200260 void *elevator_private2;
261
Jens Axboe8f34ee72006-06-13 09:02:34 +0200262 struct gendisk *rq_disk;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263 unsigned long start_time;
264
265 /* Number of scatter-gather DMA addr+len pairs after
266 * physical address coalescing is performed.
267 */
268 unsigned short nr_phys_segments;
269
270 /* Number of scatter-gather addr+len pairs after
271 * physical and DMA remapping hardware coalescing is performed.
272 * This is the number of scatter-gather entries the driver
273 * will actually have to deal with after DMA mapping is done.
274 */
275 unsigned short nr_hw_segments;
276
Jens Axboe8f34ee72006-06-13 09:02:34 +0200277 unsigned short ioprio;
278
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279 void *special;
Jens Axboe8f34ee72006-06-13 09:02:34 +0200280 char *buffer;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281
Jens Axboecdd60262006-07-28 09:32:07 +0200282 int tag;
283 int errors;
284
285 int ref_count;
286
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 /*
288 * when request is used as a packet command carrier
289 */
290 unsigned int cmd_len;
291 unsigned char cmd[BLK_MAX_CDB];
292
293 unsigned int data_len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294 unsigned int sense_len;
Jens Axboe8f34ee72006-06-13 09:02:34 +0200295 void *data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296 void *sense;
297
298 unsigned int timeout;
Mike Christie17e01f22005-11-11 05:31:37 -0600299 int retries;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300
301 /*
Jens Axboec00895a2006-09-30 20:29:12 +0200302 * completion callback.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303 */
304 rq_end_io_fn *end_io;
305 void *end_io_data;
FUJITA Tomonoriabae1fd2007-07-16 08:52:14 +0200306
307 /* for bidi */
308 struct request *next_rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309};
310
311/*
Jens Axboe4aff5e22006-08-10 08:44:47 +0200312 * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313 * requests. Some step values could eventually be made generic.
314 */
315struct request_pm_state
316{
317 /* PM state machine step value, currently driver specific */
318 int pm_step;
319 /* requested PM state value (S1, S2, S3, S4, ...) */
320 u32 pm_state;
321 void* data; /* for driver use */
322};
323
324#include <linux/elevator.h>
325
Jens Axboe165125e2007-07-24 09:28:11 +0200326typedef void (request_fn_proc) (struct request_queue *q);
327typedef int (make_request_fn) (struct request_queue *q, struct bio *bio);
328typedef int (prep_rq_fn) (struct request_queue *, struct request *);
329typedef void (unplug_fn) (struct request_queue *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330
331struct bio_vec;
Jens Axboe165125e2007-07-24 09:28:11 +0200332typedef int (merge_bvec_fn) (struct request_queue *, struct bio *, struct bio_vec *);
Jens Axboe165125e2007-07-24 09:28:11 +0200333typedef void (prepare_flush_fn) (struct request_queue *, struct request *);
Jens Axboeff856ba2006-01-09 16:02:34 +0100334typedef void (softirq_done_fn)(struct request *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335
336enum blk_queue_state {
337 Queue_down,
338 Queue_up,
339};
340
Linus Torvalds1da177e2005-04-16 15:20:36 -0700341struct blk_queue_tag {
342 struct request **tag_index; /* map of busy tags */
343 unsigned long *tag_map; /* bit map of free/busy tags */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344 int busy; /* current depth */
345 int max_depth; /* what we will send to device */
Tejun Heoba025082005-08-05 13:28:11 -0700346 int real_max_depth; /* what the array can hold */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347 atomic_t refcnt; /* map can be shared */
348};
349
350struct request_queue
351{
352 /*
353 * Together with queue_head for cacheline sharing
354 */
355 struct list_head queue_head;
356 struct request *last_merge;
357 elevator_t *elevator;
358
359 /*
360 * the queue request freelist, one for reads and one for writes
361 */
362 struct request_list rq;
363
364 request_fn_proc *request_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365 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;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369 prepare_flush_fn *prepare_flush_fn;
Jens Axboeff856ba2006-01-09 16:02:34 +0100370 softirq_done_fn *softirq_done_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371
372 /*
Tejun Heo8922e162005-10-20 16:23:44 +0200373 * Dispatch queue sorting
374 */
Jens Axboe1b47f532005-10-20 16:37:00 +0200375 sector_t end_sector;
Tejun Heo8922e162005-10-20 16:23:44 +0200376 struct request *boundary_rq;
Tejun Heo8922e162005-10-20 16:23:44 +0200377
378 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700379 * Auto-unplugging state
380 */
381 struct timer_list unplug_timer;
382 int unplug_thresh; /* After this many requests */
383 unsigned long unplug_delay; /* After this many jiffies */
384 struct work_struct unplug_work;
385
386 struct backing_dev_info backing_dev_info;
387
388 /*
389 * The queue owner gets to use this for whatever they like.
390 * ll_rw_blk doesn't touch it.
391 */
392 void *queuedata;
393
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394 /*
395 * queue needs bounce pages for pages above this limit
396 */
397 unsigned long bounce_pfn;
Al Viro8267e262005-10-21 03:20:53 -0400398 gfp_t bounce_gfp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399
400 /*
401 * various queue flags, see QUEUE_* below
402 */
403 unsigned long queue_flags;
404
405 /*
152587d2005-04-12 16:22:06 -0500406 * protects queue structures from reentrancy. ->__queue_lock should
407 * _never_ be used directly, it is queue private. always use
408 * ->queue_lock.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700409 */
152587d2005-04-12 16:22:06 -0500410 spinlock_t __queue_lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700411 spinlock_t *queue_lock;
412
413 /*
414 * queue kobject
415 */
416 struct kobject kobj;
417
418 /*
419 * queue settings
420 */
421 unsigned long nr_requests; /* Max # of requests */
422 unsigned int nr_congestion_on;
423 unsigned int nr_congestion_off;
424 unsigned int nr_batching;
425
Jens Axboe2cb2e142006-01-17 09:04:32 +0100426 unsigned int max_sectors;
427 unsigned int max_hw_sectors;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700428 unsigned short max_phys_segments;
429 unsigned short max_hw_segments;
430 unsigned short hardsect_size;
431 unsigned int max_segment_size;
432
433 unsigned long seg_boundary_mask;
434 unsigned int dma_alignment;
435
436 struct blk_queue_tag *queue_tags;
Jens Axboe6eca9002007-10-25 10:14:47 +0200437 struct list_head tag_busy_list;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700438
Tejun Heo15853af2005-11-10 08:52:05 +0100439 unsigned int nr_sorted;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440 unsigned int in_flight;
441
442 /*
443 * sg stuff
444 */
445 unsigned int sg_timeout;
446 unsigned int sg_reserved_size;
Christoph Lameter19460892005-06-23 00:08:19 -0700447 int node;
Alexey Dobriyan6c5c9342006-09-29 01:59:40 -0700448#ifdef CONFIG_BLK_DEV_IO_TRACE
Jens Axboe2056a782006-03-23 20:00:26 +0100449 struct blk_trace *blk_trace;
Alexey Dobriyan6c5c9342006-09-29 01:59:40 -0700450#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700451 /*
452 * reserved for flush operations
453 */
Tejun Heo797e7db2006-01-06 09:51:03 +0100454 unsigned int ordered, next_ordered, ordseq;
455 int orderr, ordcolor;
456 struct request pre_flush_rq, bar_rq, post_flush_rq;
457 struct request *orig_bar_rq;
Al Viro483f4af2006-03-18 18:34:37 -0500458
459 struct mutex sysfs_lock;
FUJITA Tomonorid351af02007-07-09 12:40:35 +0200460
461#if defined(CONFIG_BLK_DEV_BSG)
462 struct bsg_class_device bsg_dev;
463#endif
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 */
Qi Yong4e971822007-07-25 08:45:51 +0200469#define QUEUE_FLAG_READFULL 3 /* read queue has been filled */
470#define QUEUE_FLAG_WRITEFULL 4 /* write queue has been filled */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700471#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 */
FUJITA Tomonoriabae1fd2007-07-16 08:52:14 +0200475#define QUEUE_FLAG_BIDI 9 /* queue supports bidi requests */
Tejun Heo797e7db2006-01-06 09:51:03 +0100476
477enum {
478 /*
479 * Hardbarrier is supported with one of the following methods.
480 *
481 * NONE : hardbarrier unsupported
482 * DRAIN : ordering by draining is enough
483 * DRAIN_FLUSH : ordering by draining w/ pre and post flushes
484 * DRAIN_FUA : ordering by draining w/ pre flush and FUA write
485 * TAG : ordering by tag is enough
486 * TAG_FLUSH : ordering by tag w/ pre and post flushes
487 * TAG_FUA : ordering by tag w/ pre flush and FUA write
488 */
489 QUEUE_ORDERED_NONE = 0x00,
490 QUEUE_ORDERED_DRAIN = 0x01,
491 QUEUE_ORDERED_TAG = 0x02,
492
493 QUEUE_ORDERED_PREFLUSH = 0x10,
494 QUEUE_ORDERED_POSTFLUSH = 0x20,
495 QUEUE_ORDERED_FUA = 0x40,
496
497 QUEUE_ORDERED_DRAIN_FLUSH = QUEUE_ORDERED_DRAIN |
498 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
499 QUEUE_ORDERED_DRAIN_FUA = QUEUE_ORDERED_DRAIN |
500 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
501 QUEUE_ORDERED_TAG_FLUSH = QUEUE_ORDERED_TAG |
502 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
503 QUEUE_ORDERED_TAG_FUA = QUEUE_ORDERED_TAG |
504 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
505
506 /*
507 * Ordered operation sequence
508 */
509 QUEUE_ORDSEQ_STARTED = 0x01, /* flushing in progress */
510 QUEUE_ORDSEQ_DRAIN = 0x02, /* waiting for the queue to be drained */
511 QUEUE_ORDSEQ_PREFLUSH = 0x04, /* pre-flushing in progress */
512 QUEUE_ORDSEQ_BAR = 0x08, /* original barrier req in progress */
513 QUEUE_ORDSEQ_POSTFLUSH = 0x10, /* post-flushing in progress */
514 QUEUE_ORDSEQ_DONE = 0x20,
515};
Linus Torvalds1da177e2005-04-16 15:20:36 -0700516
517#define blk_queue_plugged(q) test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
518#define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
519#define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
Tejun Heo797e7db2006-01-06 09:51:03 +0100520#define blk_queue_flushing(q) ((q)->ordseq)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700521
Jens Axboe4aff5e22006-08-10 08:44:47 +0200522#define blk_fs_request(rq) ((rq)->cmd_type == REQ_TYPE_FS)
523#define blk_pc_request(rq) ((rq)->cmd_type == REQ_TYPE_BLOCK_PC)
524#define blk_special_request(rq) ((rq)->cmd_type == REQ_TYPE_SPECIAL)
525#define blk_sense_request(rq) ((rq)->cmd_type == REQ_TYPE_SENSE)
526
527#define blk_noretry_request(rq) ((rq)->cmd_flags & REQ_FAILFAST)
528#define blk_rq_started(rq) ((rq)->cmd_flags & REQ_STARTED)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700529
530#define blk_account_rq(rq) (blk_rq_started(rq) && blk_fs_request(rq))
531
Jens Axboe4aff5e22006-08-10 08:44:47 +0200532#define blk_pm_suspend_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND)
533#define blk_pm_resume_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_RESUME)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534#define blk_pm_request(rq) \
Jens Axboe4aff5e22006-08-10 08:44:47 +0200535 (blk_pm_suspend_request(rq) || blk_pm_resume_request(rq))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536
Jens Axboe4aff5e22006-08-10 08:44:47 +0200537#define blk_sorted_rq(rq) ((rq)->cmd_flags & REQ_SORTED)
538#define blk_barrier_rq(rq) ((rq)->cmd_flags & REQ_HARDBARRIER)
539#define blk_fua_rq(rq) ((rq)->cmd_flags & REQ_FUA)
FUJITA Tomonoriabae1fd2007-07-16 08:52:14 +0200540#define blk_bidi_rq(rq) ((rq)->next_rq != NULL)
Jens Axboebf2de6f2007-09-27 13:01:25 +0200541#define blk_empty_barrier(rq) (blk_barrier_rq(rq) && blk_fs_request(rq) && !(rq)->hard_nr_sectors)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700542
543#define list_entry_rq(ptr) list_entry((ptr), struct request, queuelist)
544
Jens Axboe4aff5e22006-08-10 08:44:47 +0200545#define rq_data_dir(rq) ((rq)->cmd_flags & 1)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700546
Jens Axboe9e2585a2006-07-28 09:26:13 +0200547/*
548 * We regard a request as sync, if it's a READ or a SYNC write.
549 */
550#define rq_is_sync(rq) (rq_data_dir((rq)) == READ || (rq)->cmd_flags & REQ_RW_SYNC)
Jens Axboe5404bc72006-08-10 09:01:02 +0200551#define rq_is_meta(rq) ((rq)->cmd_flags & REQ_RW_META)
Jens Axboe9e2585a2006-07-28 09:26:13 +0200552
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553static inline int blk_queue_full(struct request_queue *q, int rw)
554{
555 if (rw == READ)
556 return test_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
557 return test_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
558}
559
560static inline void blk_set_queue_full(struct request_queue *q, int rw)
561{
562 if (rw == READ)
563 set_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
564 else
565 set_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
566}
567
568static inline void blk_clear_queue_full(struct request_queue *q, int rw)
569{
570 if (rw == READ)
571 clear_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
572 else
573 clear_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
574}
575
576
577/*
578 * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
579 * it already be started by driver.
580 */
581#define RQ_NOMERGE_FLAGS \
582 (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER)
583#define rq_mergeable(rq) \
Jens Axboe4aff5e22006-08-10 08:44:47 +0200584 (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && blk_fs_request((rq)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585
586/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700587 * q->prep_rq_fn return values
588 */
589#define BLKPREP_OK 0 /* serve it */
590#define BLKPREP_KILL 1 /* fatal error, kill */
591#define BLKPREP_DEFER 2 /* leave on queue */
592
593extern unsigned long blk_max_low_pfn, blk_max_pfn;
594
595/*
596 * standard bounce addresses:
597 *
598 * BLK_BOUNCE_HIGH : bounce all highmem pages
599 * BLK_BOUNCE_ANY : don't bounce anything
600 * BLK_BOUNCE_ISA : bounce pages above ISA DMA boundary
601 */
602#define BLK_BOUNCE_HIGH ((u64)blk_max_low_pfn << PAGE_SHIFT)
603#define BLK_BOUNCE_ANY ((u64)blk_max_pfn << PAGE_SHIFT)
604#define BLK_BOUNCE_ISA (ISA_DMA_THRESHOLD)
605
Jens Axboe3d6392c2007-07-09 12:38:05 +0200606/*
607 * default timeout for SG_IO if none specified
608 */
609#define BLK_DEFAULT_SG_TIMEOUT (60 * HZ)
610
Christoph Lameter2a7326b2007-07-17 04:03:37 -0700611#ifdef CONFIG_BOUNCE
Linus Torvalds1da177e2005-04-16 15:20:36 -0700612extern int init_emergency_isa_pool(void);
Jens Axboe165125e2007-07-24 09:28:11 +0200613extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614#else
615static inline int init_emergency_isa_pool(void)
616{
617 return 0;
618}
Jens Axboe165125e2007-07-24 09:28:11 +0200619static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620{
621}
622#endif /* CONFIG_MMU */
623
NeilBrown5705f702007-09-25 12:35:59 +0200624struct req_iterator {
625 int i;
626 struct bio *bio;
627};
628
629/* This should not be used directly - use rq_for_each_segment */
630#define __rq_for_each_bio(_bio, rq) \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631 if ((rq->bio)) \
632 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
633
NeilBrown5705f702007-09-25 12:35:59 +0200634#define rq_for_each_segment(bvl, _rq, _iter) \
635 __rq_for_each_bio(_iter.bio, _rq) \
636 bio_for_each_segment(bvl, _iter.bio, _iter.i)
637
638#define rq_iter_last(rq, _iter) \
639 (_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)
640
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641extern int blk_register_queue(struct gendisk *disk);
642extern void blk_unregister_queue(struct gendisk *disk);
643extern void register_disk(struct gendisk *dev);
644extern void generic_make_request(struct bio *bio);
645extern void blk_put_request(struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +0200646extern void __blk_put_request(struct request_queue *, struct request *);
Tejun Heo8ffdc652006-01-06 09:49:03 +0100647extern void blk_end_sync_rq(struct request *rq, int error);
Jens Axboe165125e2007-07-24 09:28:11 +0200648extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
649extern void blk_insert_request(struct request_queue *, struct request *, int, void *);
650extern void blk_requeue_request(struct request_queue *, struct request *);
651extern void blk_plug_device(struct request_queue *);
652extern int blk_remove_plug(struct request_queue *);
653extern void blk_recount_segments(struct request_queue *, struct bio *);
FUJITA Tomonori45e79a32007-07-09 12:39:20 +0200654extern int scsi_cmd_ioctl(struct file *, struct request_queue *,
655 struct gendisk *, unsigned int, void __user *);
Christoph Hellwig21b2f0c2006-03-22 17:52:04 +0100656extern int sg_scsi_ioctl(struct file *, struct request_queue *,
657 struct gendisk *, struct scsi_ioctl_command __user *);
Andrew Morton3fcfab12006-10-19 23:28:16 -0700658
659/*
Jens Axboe1aa4f242006-12-19 08:33:11 +0100660 * Temporary export, until SCSI gets fixed up.
661 */
NeilBrown3001ca72007-08-16 13:31:27 +0200662extern int blk_rq_append_bio(struct request_queue *q, struct request *rq,
663 struct bio *bio);
Jens Axboe1aa4f242006-12-19 08:33:11 +0100664
665/*
Andrew Morton3fcfab12006-10-19 23:28:16 -0700666 * A queue has just exitted congestion. Note this in the global counter of
667 * congested queues, and wake up anyone who was waiting for requests to be
668 * put back.
669 */
Jens Axboe165125e2007-07-24 09:28:11 +0200670static inline void blk_clear_queue_congested(struct request_queue *q, int rw)
Andrew Morton3fcfab12006-10-19 23:28:16 -0700671{
672 clear_bdi_congested(&q->backing_dev_info, rw);
673}
674
675/*
676 * A queue has just entered congestion. Flag that in the queue's VM-visible
677 * state flags and increment the global gounter of congested queues.
678 */
Jens Axboe165125e2007-07-24 09:28:11 +0200679static inline void blk_set_queue_congested(struct request_queue *q, int rw)
Andrew Morton3fcfab12006-10-19 23:28:16 -0700680{
681 set_bdi_congested(&q->backing_dev_info, rw);
682}
683
Jens Axboe165125e2007-07-24 09:28:11 +0200684extern void blk_start_queue(struct request_queue *q);
685extern void blk_stop_queue(struct request_queue *q);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700686extern void blk_sync_queue(struct request_queue *q);
Jens Axboe165125e2007-07-24 09:28:11 +0200687extern void __blk_stop_queue(struct request_queue *q);
688extern void blk_run_queue(struct request_queue *);
689extern void blk_start_queueing(struct request_queue *);
690extern int blk_rq_map_user(struct request_queue *, struct request *, void __user *, unsigned long);
Jens Axboe8e5cfc42006-12-19 11:12:46 +0100691extern int blk_rq_unmap_user(struct bio *);
Jens Axboe165125e2007-07-24 09:28:11 +0200692extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
693extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
Mike Christie0e75f902006-12-01 10:40:55 +0100694 struct sg_iovec *, int, unsigned int);
Jens Axboe165125e2007-07-24 09:28:11 +0200695extern int blk_execute_rq(struct request_queue *, struct gendisk *,
James Bottomley 994ca9a2005-06-20 14:11:09 +0200696 struct request *, int);
Jens Axboe165125e2007-07-24 09:28:11 +0200697extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
Jens Axboe15fc8582006-01-06 10:00:50 +0100698 struct request *, int, rq_end_io_fn *);
FUJITA Tomonori337ad412006-12-20 11:18:54 +0100699extern int blk_verify_command(unsigned char *, int);
Mike Christie6e39b692005-11-11 05:30:24 -0600700
Jens Axboe165125e2007-07-24 09:28:11 +0200701static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700702{
703 return bdev->bd_disk->queue;
704}
705
706static inline void blk_run_backing_dev(struct backing_dev_info *bdi,
707 struct page *page)
708{
709 if (bdi && bdi->unplug_io_fn)
710 bdi->unplug_io_fn(bdi, page);
711}
712
713static inline void blk_run_address_space(struct address_space *mapping)
714{
715 if (mapping)
716 blk_run_backing_dev(mapping->backing_dev_info, NULL);
717}
718
719/*
720 * end_request() and friends. Must be called with the request queue spinlock
721 * acquired. All functions called within end_request() _must_be_ atomic.
722 *
723 * Several drivers define their own end_request and call
724 * end_that_request_first() and end_that_request_last()
725 * for parts of the original function. This prevents
726 * code duplication in drivers.
727 */
728extern int end_that_request_first(struct request *, int, int);
729extern int end_that_request_chunk(struct request *, int, int);
Tejun Heo8ffdc652006-01-06 09:49:03 +0100730extern void end_that_request_last(struct request *, int);
Jens Axboea0cd1282007-09-21 10:41:07 +0200731extern void end_request(struct request *, int);
732extern void end_queued_request(struct request *, int);
733extern void end_dequeued_request(struct request *, int);
Jens Axboeff856ba2006-01-09 16:02:34 +0100734extern void blk_complete_request(struct request *);
735
Linus Torvalds1da177e2005-04-16 15:20:36 -0700736/*
737 * end_that_request_first/chunk() takes an uptodate argument. we account
738 * any value <= as an io error. 0 means -EIO for compatability reasons,
739 * any other < 0 value is the direct error type. An uptodate value of
740 * 1 indicates successful io completion
741 */
742#define end_io_error(uptodate) (unlikely((uptodate) <= 0))
743
744static inline void blkdev_dequeue_request(struct request *req)
745{
Tejun Heo8922e162005-10-20 16:23:44 +0200746 elv_dequeue_request(req->q, req);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700747}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700748
Linus Torvalds1da177e2005-04-16 15:20:36 -0700749/*
750 * Access functions for manipulating queue properties
751 */
Jens Axboe165125e2007-07-24 09:28:11 +0200752extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
Christoph Lameter19460892005-06-23 00:08:19 -0700753 spinlock_t *lock, int node_id);
Jens Axboe165125e2007-07-24 09:28:11 +0200754extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
755extern void blk_cleanup_queue(struct request_queue *);
756extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
757extern void blk_queue_bounce_limit(struct request_queue *, u64);
758extern void blk_queue_max_sectors(struct request_queue *, unsigned int);
759extern void blk_queue_max_phys_segments(struct request_queue *, unsigned short);
760extern void blk_queue_max_hw_segments(struct request_queue *, unsigned short);
761extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
762extern void blk_queue_hardsect_size(struct request_queue *, unsigned short);
763extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
764extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
765extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
766extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
767extern void blk_queue_dma_alignment(struct request_queue *, int);
768extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700769extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
Jens Axboe165125e2007-07-24 09:28:11 +0200770extern int blk_queue_ordered(struct request_queue *, unsigned, prepare_flush_fn *);
Jens Axboe165125e2007-07-24 09:28:11 +0200771extern int blk_do_ordered(struct request_queue *, struct request **);
772extern unsigned blk_ordered_cur_seq(struct request_queue *);
Tejun Heo797e7db2006-01-06 09:51:03 +0100773extern unsigned blk_ordered_req_seq(struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +0200774extern void blk_ordered_complete_seq(struct request_queue *, unsigned, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775
Jens Axboe165125e2007-07-24 09:28:11 +0200776extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700777extern void blk_dump_rq_flags(struct request *, char *);
Jens Axboe165125e2007-07-24 09:28:11 +0200778extern void generic_unplug_device(struct request_queue *);
779extern void __generic_unplug_device(struct request_queue *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700780extern long nr_blockdev_pages(void);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700781
Jens Axboe165125e2007-07-24 09:28:11 +0200782int blk_get_queue(struct request_queue *);
783struct request_queue *blk_alloc_queue(gfp_t);
784struct request_queue *blk_alloc_queue_node(gfp_t, int);
785extern void blk_put_queue(struct request_queue *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700786
787/*
788 * tag stuff
789 */
790#define blk_queue_tag_depth(q) ((q)->queue_tags->busy)
791#define blk_queue_tag_queue(q) ((q)->queue_tags->busy < (q)->queue_tags->max_depth)
Jens Axboe4aff5e22006-08-10 08:44:47 +0200792#define blk_rq_tagged(rq) ((rq)->cmd_flags & REQ_QUEUED)
Jens Axboe165125e2007-07-24 09:28:11 +0200793extern int blk_queue_start_tag(struct request_queue *, struct request *);
794extern struct request *blk_queue_find_tag(struct request_queue *, int);
795extern void blk_queue_end_tag(struct request_queue *, struct request *);
796extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *);
797extern void blk_queue_free_tags(struct request_queue *);
798extern int blk_queue_resize_tags(struct request_queue *, int);
799extern void blk_queue_invalidate_tags(struct request_queue *);
James Bottomley492dfb42006-08-30 15:48:45 -0400800extern struct blk_queue_tag *blk_init_tags(int);
801extern void blk_free_tags(struct blk_queue_tag *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700802
David C Somayajuluf583f492006-10-04 08:27:25 +0200803static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
804 int tag)
805{
806 if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
807 return NULL;
808 return bqt->tag_index[tag];
809}
810
Linus Torvalds1da177e2005-04-16 15:20:36 -0700811extern int blkdev_issue_flush(struct block_device *, sector_t *);
812
813#define MAX_PHYS_SEGMENTS 128
814#define MAX_HW_SEGMENTS 128
Mike Christiedefd94b2005-12-05 02:37:06 -0600815#define SAFE_MAX_SECTORS 255
816#define BLK_DEF_MAX_SECTORS 1024
Linus Torvalds1da177e2005-04-16 15:20:36 -0700817
818#define MAX_SEGMENT_SIZE 65536
819
820#define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
821
Jens Axboe165125e2007-07-24 09:28:11 +0200822static inline int queue_hardsect_size(struct request_queue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700823{
824 int retval = 512;
825
826 if (q && q->hardsect_size)
827 retval = q->hardsect_size;
828
829 return retval;
830}
831
832static inline int bdev_hardsect_size(struct block_device *bdev)
833{
834 return queue_hardsect_size(bdev_get_queue(bdev));
835}
836
Jens Axboe165125e2007-07-24 09:28:11 +0200837static inline int queue_dma_alignment(struct request_queue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700838{
839 int retval = 511;
840
841 if (q && q->dma_alignment)
842 retval = q->dma_alignment;
843
844 return retval;
845}
846
Linus Torvalds1da177e2005-04-16 15:20:36 -0700847/* assumes size > 256 */
848static inline unsigned int blksize_bits(unsigned int size)
849{
850 unsigned int bits = 8;
851 do {
852 bits++;
853 size >>= 1;
854 } while (size > 256);
855 return bits;
856}
857
Adrian Bunk2befb9e2005-09-10 00:27:17 -0700858static inline unsigned int block_size(struct block_device *bdev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700859{
860 return bdev->bd_block_size;
861}
862
863typedef struct {struct page *v;} Sector;
864
865unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
866
867static inline void put_dev_sector(Sector p)
868{
869 page_cache_release(p.v);
870}
871
872struct work_struct;
873int kblockd_schedule_work(struct work_struct *work);
Andrew Morton19a75d82007-05-09 02:33:56 -0700874void kblockd_flush_work(struct work_struct *work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700875
Linus Torvalds1da177e2005-04-16 15:20:36 -0700876#define MODULE_ALIAS_BLOCKDEV(major,minor) \
877 MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
878#define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
879 MODULE_ALIAS("block-major-" __stringify(major) "-*")
880
881
David Howells93614012006-09-30 20:45:40 +0200882#else /* CONFIG_BLOCK */
883/*
884 * stubs for when the block layer is configured out
885 */
886#define buffer_heads_over_limit 0
887
David Howells93614012006-09-30 20:45:40 +0200888static inline long nr_blockdev_pages(void)
889{
890 return 0;
891}
892
Andrew Mortonbcfd8d32006-08-31 12:56:06 +0200893static inline void exit_io_context(void)
894{
895}
David Howells93614012006-09-30 20:45:40 +0200896
897#endif /* CONFIG_BLOCK */
898
Linus Torvalds1da177e2005-04-16 15:20:36 -0700899#endif