blob: 90392a9d7a9c782f3745db67b89b03bd67ba588c [file] [log] [blame]
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/*
140 * try to put the fields that are referenced together in the same cacheline
141 */
142struct request {
Jens Axboeff856ba2006-01-09 16:02:34 +0100143 struct list_head queuelist;
144 struct list_head donelist;
145
Jens Axboe165125e2007-07-24 09:28:11 +0200146 struct request_queue *q;
Jens Axboee6a1c872006-08-10 09:00:21 +0200147
Jens Axboe4aff5e22006-08-10 08:44:47 +0200148 unsigned int cmd_flags;
149 enum rq_cmd_type_bits cmd_type;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150
151 /* Maintain bio traversal state for part by part I/O submission.
152 * hard_* are block layer internals, no driver should touch them!
153 */
154
155 sector_t sector; /* next sector to submit */
Jens Axboee6a1c872006-08-10 09:00:21 +0200156 sector_t hard_sector; /* next sector to complete */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157 unsigned long nr_sectors; /* no. of sectors left to submit */
Jens Axboee6a1c872006-08-10 09:00:21 +0200158 unsigned long hard_nr_sectors; /* no. of sectors left to complete */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159 /* no. of sectors left to submit in the current segment */
160 unsigned int current_nr_sectors;
161
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162 /* no. of sectors left to complete in the current segment */
163 unsigned int hard_cur_sectors;
164
165 struct bio *bio;
166 struct bio *biotail;
167
Jens Axboe98170642006-07-28 09:23:08 +0200168 struct hlist_node hash; /* merge hash */
Jens Axboee6a1c872006-08-10 09:00:21 +0200169 /*
170 * The rb_node is only used inside the io scheduler, requests
171 * are pruned when moved to the dispatch queue. So let the
172 * completion_data share space with the rb_node.
173 */
174 union {
175 struct rb_node rb_node; /* sort/lookup */
176 void *completion_data;
177 };
Jens Axboe98170642006-07-28 09:23:08 +0200178
Jens Axboeff7d1452006-07-12 14:04:37 +0200179 /*
180 * two pointers are available for the IO schedulers, if they need
181 * more they have to dynamically allocate it.
182 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183 void *elevator_private;
Jens Axboeff7d1452006-07-12 14:04:37 +0200184 void *elevator_private2;
185
Jens Axboe8f34ee72006-06-13 09:02:34 +0200186 struct gendisk *rq_disk;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187 unsigned long start_time;
188
189 /* Number of scatter-gather DMA addr+len pairs after
190 * physical address coalescing is performed.
191 */
192 unsigned short nr_phys_segments;
193
194 /* Number of scatter-gather addr+len pairs after
195 * physical and DMA remapping hardware coalescing is performed.
196 * This is the number of scatter-gather entries the driver
197 * will actually have to deal with after DMA mapping is done.
198 */
199 unsigned short nr_hw_segments;
200
Jens Axboe8f34ee72006-06-13 09:02:34 +0200201 unsigned short ioprio;
202
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 void *special;
Jens Axboe8f34ee72006-06-13 09:02:34 +0200204 char *buffer;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205
Jens Axboecdd60262006-07-28 09:32:07 +0200206 int tag;
207 int errors;
208
209 int ref_count;
210
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211 /*
212 * when request is used as a packet command carrier
213 */
214 unsigned int cmd_len;
215 unsigned char cmd[BLK_MAX_CDB];
216
217 unsigned int data_len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 unsigned int sense_len;
Jens Axboe8f34ee72006-06-13 09:02:34 +0200219 void *data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 void *sense;
221
222 unsigned int timeout;
Mike Christie17e01f22005-11-11 05:31:37 -0600223 int retries;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224
225 /*
Jens Axboec00895a2006-09-30 20:29:12 +0200226 * completion callback.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227 */
228 rq_end_io_fn *end_io;
229 void *end_io_data;
FUJITA Tomonoriabae1fd2007-07-16 08:52:14 +0200230
231 /* for bidi */
232 struct request *next_rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233};
234
235/*
Jens Axboe4aff5e22006-08-10 08:44:47 +0200236 * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237 * requests. Some step values could eventually be made generic.
238 */
239struct request_pm_state
240{
241 /* PM state machine step value, currently driver specific */
242 int pm_step;
243 /* requested PM state value (S1, S2, S3, S4, ...) */
244 u32 pm_state;
245 void* data; /* for driver use */
246};
247
248#include <linux/elevator.h>
249
Jens Axboe165125e2007-07-24 09:28:11 +0200250typedef void (request_fn_proc) (struct request_queue *q);
251typedef int (make_request_fn) (struct request_queue *q, struct bio *bio);
252typedef int (prep_rq_fn) (struct request_queue *, struct request *);
253typedef void (unplug_fn) (struct request_queue *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254
255struct bio_vec;
Jens Axboe165125e2007-07-24 09:28:11 +0200256typedef int (merge_bvec_fn) (struct request_queue *, struct bio *, struct bio_vec *);
Jens Axboe165125e2007-07-24 09:28:11 +0200257typedef void (prepare_flush_fn) (struct request_queue *, struct request *);
Jens Axboeff856ba2006-01-09 16:02:34 +0100258typedef void (softirq_done_fn)(struct request *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259
260enum blk_queue_state {
261 Queue_down,
262 Queue_up,
263};
264
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265struct blk_queue_tag {
266 struct request **tag_index; /* map of busy tags */
267 unsigned long *tag_map; /* bit map of free/busy tags */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268 int busy; /* current depth */
269 int max_depth; /* what we will send to device */
Tejun Heoba025082005-08-05 13:28:11 -0700270 int real_max_depth; /* what the array can hold */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 atomic_t refcnt; /* map can be shared */
272};
273
274struct request_queue
275{
276 /*
277 * Together with queue_head for cacheline sharing
278 */
279 struct list_head queue_head;
280 struct request *last_merge;
281 elevator_t *elevator;
282
283 /*
284 * the queue request freelist, one for reads and one for writes
285 */
286 struct request_list rq;
287
288 request_fn_proc *request_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289 make_request_fn *make_request_fn;
290 prep_rq_fn *prep_rq_fn;
291 unplug_fn *unplug_fn;
292 merge_bvec_fn *merge_bvec_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293 prepare_flush_fn *prepare_flush_fn;
Jens Axboeff856ba2006-01-09 16:02:34 +0100294 softirq_done_fn *softirq_done_fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295
296 /*
Tejun Heo8922e162005-10-20 16:23:44 +0200297 * Dispatch queue sorting
298 */
Jens Axboe1b47f532005-10-20 16:37:00 +0200299 sector_t end_sector;
Tejun Heo8922e162005-10-20 16:23:44 +0200300 struct request *boundary_rq;
Tejun Heo8922e162005-10-20 16:23:44 +0200301
302 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303 * Auto-unplugging state
304 */
305 struct timer_list unplug_timer;
306 int unplug_thresh; /* After this many requests */
307 unsigned long unplug_delay; /* After this many jiffies */
308 struct work_struct unplug_work;
309
310 struct backing_dev_info backing_dev_info;
311
312 /*
313 * The queue owner gets to use this for whatever they like.
314 * ll_rw_blk doesn't touch it.
315 */
316 void *queuedata;
317
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318 /*
319 * queue needs bounce pages for pages above this limit
320 */
321 unsigned long bounce_pfn;
Al Viro8267e262005-10-21 03:20:53 -0400322 gfp_t bounce_gfp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323
324 /*
325 * various queue flags, see QUEUE_* below
326 */
327 unsigned long queue_flags;
328
329 /*
152587d2005-04-12 16:22:06 -0500330 * protects queue structures from reentrancy. ->__queue_lock should
331 * _never_ be used directly, it is queue private. always use
332 * ->queue_lock.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333 */
152587d2005-04-12 16:22:06 -0500334 spinlock_t __queue_lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335 spinlock_t *queue_lock;
336
337 /*
338 * queue kobject
339 */
340 struct kobject kobj;
341
342 /*
343 * queue settings
344 */
345 unsigned long nr_requests; /* Max # of requests */
346 unsigned int nr_congestion_on;
347 unsigned int nr_congestion_off;
348 unsigned int nr_batching;
349
Jens Axboe2cb2e142006-01-17 09:04:32 +0100350 unsigned int max_sectors;
351 unsigned int max_hw_sectors;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700352 unsigned short max_phys_segments;
353 unsigned short max_hw_segments;
354 unsigned short hardsect_size;
355 unsigned int max_segment_size;
356
357 unsigned long seg_boundary_mask;
James Bottomleyfa0ccd82008-01-10 11:30:36 -0600358 void *dma_drain_buffer;
359 unsigned int dma_drain_size;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360 unsigned int dma_alignment;
361
362 struct blk_queue_tag *queue_tags;
Jens Axboe6eca9002007-10-25 10:14:47 +0200363 struct list_head tag_busy_list;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364
Tejun Heo15853af2005-11-10 08:52:05 +0100365 unsigned int nr_sorted;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366 unsigned int in_flight;
367
368 /*
369 * sg stuff
370 */
371 unsigned int sg_timeout;
372 unsigned int sg_reserved_size;
Christoph Lameter19460892005-06-23 00:08:19 -0700373 int node;
Alexey Dobriyan6c5c9342006-09-29 01:59:40 -0700374#ifdef CONFIG_BLK_DEV_IO_TRACE
Jens Axboe2056a782006-03-23 20:00:26 +0100375 struct blk_trace *blk_trace;
Alexey Dobriyan6c5c9342006-09-29 01:59:40 -0700376#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377 /*
378 * reserved for flush operations
379 */
Tejun Heo797e7db2006-01-06 09:51:03 +0100380 unsigned int ordered, next_ordered, ordseq;
381 int orderr, ordcolor;
382 struct request pre_flush_rq, bar_rq, post_flush_rq;
383 struct request *orig_bar_rq;
Al Viro483f4af2006-03-18 18:34:37 -0500384
385 struct mutex sysfs_lock;
FUJITA Tomonorid351af02007-07-09 12:40:35 +0200386
387#if defined(CONFIG_BLK_DEV_BSG)
388 struct bsg_class_device bsg_dev;
389#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390};
391
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392#define QUEUE_FLAG_CLUSTER 0 /* cluster several segments into 1 */
393#define QUEUE_FLAG_QUEUED 1 /* uses generic tag queueing */
394#define QUEUE_FLAG_STOPPED 2 /* queue is stopped */
Qi Yong4e971822007-07-25 08:45:51 +0200395#define QUEUE_FLAG_READFULL 3 /* read queue has been filled */
396#define QUEUE_FLAG_WRITEFULL 4 /* write queue has been filled */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397#define QUEUE_FLAG_DEAD 5 /* queue being torn down */
398#define QUEUE_FLAG_REENTER 6 /* Re-entrancy avoidance */
399#define QUEUE_FLAG_PLUGGED 7 /* queue is plugged */
Jens Axboe64521d12005-10-28 08:30:39 +0200400#define QUEUE_FLAG_ELVSWITCH 8 /* don't use elevator, just do FIFO */
FUJITA Tomonoriabae1fd2007-07-16 08:52:14 +0200401#define QUEUE_FLAG_BIDI 9 /* queue supports bidi requests */
Tejun Heo797e7db2006-01-06 09:51:03 +0100402
403enum {
404 /*
405 * Hardbarrier is supported with one of the following methods.
406 *
407 * NONE : hardbarrier unsupported
408 * DRAIN : ordering by draining is enough
409 * DRAIN_FLUSH : ordering by draining w/ pre and post flushes
410 * DRAIN_FUA : ordering by draining w/ pre flush and FUA write
411 * TAG : ordering by tag is enough
412 * TAG_FLUSH : ordering by tag w/ pre and post flushes
413 * TAG_FUA : ordering by tag w/ pre flush and FUA write
414 */
415 QUEUE_ORDERED_NONE = 0x00,
416 QUEUE_ORDERED_DRAIN = 0x01,
417 QUEUE_ORDERED_TAG = 0x02,
418
419 QUEUE_ORDERED_PREFLUSH = 0x10,
420 QUEUE_ORDERED_POSTFLUSH = 0x20,
421 QUEUE_ORDERED_FUA = 0x40,
422
423 QUEUE_ORDERED_DRAIN_FLUSH = QUEUE_ORDERED_DRAIN |
424 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
425 QUEUE_ORDERED_DRAIN_FUA = QUEUE_ORDERED_DRAIN |
426 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
427 QUEUE_ORDERED_TAG_FLUSH = QUEUE_ORDERED_TAG |
428 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH,
429 QUEUE_ORDERED_TAG_FUA = QUEUE_ORDERED_TAG |
430 QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_FUA,
431
432 /*
433 * Ordered operation sequence
434 */
435 QUEUE_ORDSEQ_STARTED = 0x01, /* flushing in progress */
436 QUEUE_ORDSEQ_DRAIN = 0x02, /* waiting for the queue to be drained */
437 QUEUE_ORDSEQ_PREFLUSH = 0x04, /* pre-flushing in progress */
438 QUEUE_ORDSEQ_BAR = 0x08, /* original barrier req in progress */
439 QUEUE_ORDSEQ_POSTFLUSH = 0x10, /* post-flushing in progress */
440 QUEUE_ORDSEQ_DONE = 0x20,
441};
Linus Torvalds1da177e2005-04-16 15:20:36 -0700442
443#define blk_queue_plugged(q) test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
444#define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
445#define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
Tejun Heo797e7db2006-01-06 09:51:03 +0100446#define blk_queue_flushing(q) ((q)->ordseq)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447
Jens Axboe4aff5e22006-08-10 08:44:47 +0200448#define blk_fs_request(rq) ((rq)->cmd_type == REQ_TYPE_FS)
449#define blk_pc_request(rq) ((rq)->cmd_type == REQ_TYPE_BLOCK_PC)
450#define blk_special_request(rq) ((rq)->cmd_type == REQ_TYPE_SPECIAL)
451#define blk_sense_request(rq) ((rq)->cmd_type == REQ_TYPE_SENSE)
452
453#define blk_noretry_request(rq) ((rq)->cmd_flags & REQ_FAILFAST)
454#define blk_rq_started(rq) ((rq)->cmd_flags & REQ_STARTED)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700455
456#define blk_account_rq(rq) (blk_rq_started(rq) && blk_fs_request(rq))
457
Jens Axboe4aff5e22006-08-10 08:44:47 +0200458#define blk_pm_suspend_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND)
459#define blk_pm_resume_request(rq) ((rq)->cmd_type == REQ_TYPE_PM_RESUME)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700460#define blk_pm_request(rq) \
Jens Axboe4aff5e22006-08-10 08:44:47 +0200461 (blk_pm_suspend_request(rq) || blk_pm_resume_request(rq))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700462
Jens Axboe4aff5e22006-08-10 08:44:47 +0200463#define blk_sorted_rq(rq) ((rq)->cmd_flags & REQ_SORTED)
464#define blk_barrier_rq(rq) ((rq)->cmd_flags & REQ_HARDBARRIER)
465#define blk_fua_rq(rq) ((rq)->cmd_flags & REQ_FUA)
FUJITA Tomonoriabae1fd2007-07-16 08:52:14 +0200466#define blk_bidi_rq(rq) ((rq)->next_rq != NULL)
Jens Axboebf2de6f2007-09-27 13:01:25 +0200467#define blk_empty_barrier(rq) (blk_barrier_rq(rq) && blk_fs_request(rq) && !(rq)->hard_nr_sectors)
Kiyoshi Ueda336cdb42007-12-11 17:40:30 -0500468/* rq->queuelist of dequeued request must be list_empty() */
469#define blk_queued_rq(rq) (!list_empty(&(rq)->queuelist))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700470
471#define list_entry_rq(ptr) list_entry((ptr), struct request, queuelist)
472
Jens Axboe4aff5e22006-08-10 08:44:47 +0200473#define rq_data_dir(rq) ((rq)->cmd_flags & 1)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700474
Jens Axboe9e2585a2006-07-28 09:26:13 +0200475/*
476 * We regard a request as sync, if it's a READ or a SYNC write.
477 */
478#define rq_is_sync(rq) (rq_data_dir((rq)) == READ || (rq)->cmd_flags & REQ_RW_SYNC)
Jens Axboe5404bc72006-08-10 09:01:02 +0200479#define rq_is_meta(rq) ((rq)->cmd_flags & REQ_RW_META)
Jens Axboe9e2585a2006-07-28 09:26:13 +0200480
Linus Torvalds1da177e2005-04-16 15:20:36 -0700481static inline int blk_queue_full(struct request_queue *q, int rw)
482{
483 if (rw == READ)
484 return test_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
485 return test_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
486}
487
488static inline void blk_set_queue_full(struct request_queue *q, int rw)
489{
490 if (rw == READ)
491 set_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
492 else
493 set_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
494}
495
496static inline void blk_clear_queue_full(struct request_queue *q, int rw)
497{
498 if (rw == READ)
499 clear_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
500 else
501 clear_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
502}
503
504
505/*
506 * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
507 * it already be started by driver.
508 */
509#define RQ_NOMERGE_FLAGS \
510 (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER)
511#define rq_mergeable(rq) \
Jens Axboe4aff5e22006-08-10 08:44:47 +0200512 (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && blk_fs_request((rq)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700513
514/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700515 * q->prep_rq_fn return values
516 */
517#define BLKPREP_OK 0 /* serve it */
518#define BLKPREP_KILL 1 /* fatal error, kill */
519#define BLKPREP_DEFER 2 /* leave on queue */
520
521extern unsigned long blk_max_low_pfn, blk_max_pfn;
522
523/*
524 * standard bounce addresses:
525 *
526 * BLK_BOUNCE_HIGH : bounce all highmem pages
527 * BLK_BOUNCE_ANY : don't bounce anything
528 * BLK_BOUNCE_ISA : bounce pages above ISA DMA boundary
529 */
530#define BLK_BOUNCE_HIGH ((u64)blk_max_low_pfn << PAGE_SHIFT)
531#define BLK_BOUNCE_ANY ((u64)blk_max_pfn << PAGE_SHIFT)
532#define BLK_BOUNCE_ISA (ISA_DMA_THRESHOLD)
533
Jens Axboe3d6392c2007-07-09 12:38:05 +0200534/*
535 * default timeout for SG_IO if none specified
536 */
537#define BLK_DEFAULT_SG_TIMEOUT (60 * HZ)
538
Christoph Lameter2a7326b2007-07-17 04:03:37 -0700539#ifdef CONFIG_BOUNCE
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540extern int init_emergency_isa_pool(void);
Jens Axboe165125e2007-07-24 09:28:11 +0200541extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700542#else
543static inline int init_emergency_isa_pool(void)
544{
545 return 0;
546}
Jens Axboe165125e2007-07-24 09:28:11 +0200547static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548{
549}
550#endif /* CONFIG_MMU */
551
NeilBrown5705f702007-09-25 12:35:59 +0200552struct req_iterator {
553 int i;
554 struct bio *bio;
555};
556
557/* This should not be used directly - use rq_for_each_segment */
558#define __rq_for_each_bio(_bio, rq) \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559 if ((rq->bio)) \
560 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
561
NeilBrown5705f702007-09-25 12:35:59 +0200562#define rq_for_each_segment(bvl, _rq, _iter) \
563 __rq_for_each_bio(_iter.bio, _rq) \
564 bio_for_each_segment(bvl, _iter.bio, _iter.i)
565
566#define rq_iter_last(rq, _iter) \
567 (_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)
568
Linus Torvalds1da177e2005-04-16 15:20:36 -0700569extern int blk_register_queue(struct gendisk *disk);
570extern void blk_unregister_queue(struct gendisk *disk);
571extern void register_disk(struct gendisk *dev);
572extern void generic_make_request(struct bio *bio);
573extern void blk_put_request(struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +0200574extern void __blk_put_request(struct request_queue *, struct request *);
Tejun Heo8ffdc652006-01-06 09:49:03 +0100575extern void blk_end_sync_rq(struct request *rq, int error);
Jens Axboe165125e2007-07-24 09:28:11 +0200576extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
577extern void blk_insert_request(struct request_queue *, struct request *, int, void *);
578extern void blk_requeue_request(struct request_queue *, struct request *);
579extern void blk_plug_device(struct request_queue *);
580extern int blk_remove_plug(struct request_queue *);
581extern void blk_recount_segments(struct request_queue *, struct bio *);
FUJITA Tomonori45e79a32007-07-09 12:39:20 +0200582extern int scsi_cmd_ioctl(struct file *, struct request_queue *,
583 struct gendisk *, unsigned int, void __user *);
Christoph Hellwig21b2f0c2006-03-22 17:52:04 +0100584extern int sg_scsi_ioctl(struct file *, struct request_queue *,
585 struct gendisk *, struct scsi_ioctl_command __user *);
Andrew Morton3fcfab12006-10-19 23:28:16 -0700586
587/*
Jens Axboe1aa4f242006-12-19 08:33:11 +0100588 * Temporary export, until SCSI gets fixed up.
589 */
NeilBrown3001ca72007-08-16 13:31:27 +0200590extern int blk_rq_append_bio(struct request_queue *q, struct request *rq,
591 struct bio *bio);
Jens Axboe1aa4f242006-12-19 08:33:11 +0100592
593/*
Andrew Morton3fcfab12006-10-19 23:28:16 -0700594 * A queue has just exitted congestion. Note this in the global counter of
595 * congested queues, and wake up anyone who was waiting for requests to be
596 * put back.
597 */
Jens Axboe165125e2007-07-24 09:28:11 +0200598static inline void blk_clear_queue_congested(struct request_queue *q, int rw)
Andrew Morton3fcfab12006-10-19 23:28:16 -0700599{
600 clear_bdi_congested(&q->backing_dev_info, rw);
601}
602
603/*
604 * A queue has just entered congestion. Flag that in the queue's VM-visible
605 * state flags and increment the global gounter of congested queues.
606 */
Jens Axboe165125e2007-07-24 09:28:11 +0200607static inline void blk_set_queue_congested(struct request_queue *q, int rw)
Andrew Morton3fcfab12006-10-19 23:28:16 -0700608{
609 set_bdi_congested(&q->backing_dev_info, rw);
610}
611
Jens Axboe165125e2007-07-24 09:28:11 +0200612extern void blk_start_queue(struct request_queue *q);
613extern void blk_stop_queue(struct request_queue *q);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614extern void blk_sync_queue(struct request_queue *q);
Jens Axboe165125e2007-07-24 09:28:11 +0200615extern void __blk_stop_queue(struct request_queue *q);
616extern void blk_run_queue(struct request_queue *);
617extern void blk_start_queueing(struct request_queue *);
618extern int blk_rq_map_user(struct request_queue *, struct request *, void __user *, unsigned long);
Jens Axboe8e5cfc42006-12-19 11:12:46 +0100619extern int blk_rq_unmap_user(struct bio *);
Jens Axboe165125e2007-07-24 09:28:11 +0200620extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t);
621extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
Mike Christie0e75f902006-12-01 10:40:55 +0100622 struct sg_iovec *, int, unsigned int);
Jens Axboe165125e2007-07-24 09:28:11 +0200623extern int blk_execute_rq(struct request_queue *, struct gendisk *,
James Bottomley 994ca9a2005-06-20 14:11:09 +0200624 struct request *, int);
Jens Axboe165125e2007-07-24 09:28:11 +0200625extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
Jens Axboe15fc8582006-01-06 10:00:50 +0100626 struct request *, int, rq_end_io_fn *);
FUJITA Tomonori337ad412006-12-20 11:18:54 +0100627extern int blk_verify_command(unsigned char *, int);
Alan D. Brunelle2ad8b1e2007-11-07 14:26:56 -0500628extern void blk_unplug(struct request_queue *q);
Mike Christie6e39b692005-11-11 05:30:24 -0600629
Jens Axboe165125e2007-07-24 09:28:11 +0200630static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631{
632 return bdev->bd_disk->queue;
633}
634
635static inline void blk_run_backing_dev(struct backing_dev_info *bdi,
636 struct page *page)
637{
638 if (bdi && bdi->unplug_io_fn)
639 bdi->unplug_io_fn(bdi, page);
640}
641
642static inline void blk_run_address_space(struct address_space *mapping)
643{
644 if (mapping)
645 blk_run_backing_dev(mapping->backing_dev_info, NULL);
646}
647
648/*
Kiyoshi Ueda3bcddea2007-12-11 17:52:28 -0500649 * blk_end_request() and friends.
650 * __blk_end_request() and end_request() must be called with
651 * the request queue spinlock acquired.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652 *
653 * Several drivers define their own end_request and call
Kiyoshi Ueda3bcddea2007-12-11 17:52:28 -0500654 * blk_end_request() for parts of the original function.
655 * This prevents code duplication in drivers.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700656 */
Jens Axboe22b13212008-01-31 12:36:19 +0100657extern int blk_end_request(struct request *rq, int error,
658 unsigned int nr_bytes);
659extern int __blk_end_request(struct request *rq, int error,
660 unsigned int nr_bytes);
661extern int blk_end_bidi_request(struct request *rq, int error,
662 unsigned int nr_bytes, unsigned int bidi_bytes);
Jens Axboea0cd1282007-09-21 10:41:07 +0200663extern void end_request(struct request *, int);
664extern void end_queued_request(struct request *, int);
665extern void end_dequeued_request(struct request *, int);
Jens Axboe22b13212008-01-31 12:36:19 +0100666extern int blk_end_request_callback(struct request *rq, int error,
667 unsigned int nr_bytes,
668 int (drv_callback)(struct request *));
Jens Axboeff856ba2006-01-09 16:02:34 +0100669extern void blk_complete_request(struct request *);
670
Linus Torvalds1da177e2005-04-16 15:20:36 -0700671/*
Kiyoshi Ueda3b113132007-12-11 17:41:17 -0500672 * blk_end_request() takes bytes instead of sectors as a complete size.
673 * blk_rq_bytes() returns bytes left to complete in the entire request.
674 * blk_rq_cur_bytes() returns bytes left to complete in the current segment.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700675 */
Kiyoshi Ueda3b113132007-12-11 17:41:17 -0500676extern unsigned int blk_rq_bytes(struct request *rq);
677extern unsigned int blk_rq_cur_bytes(struct request *rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700678
679static inline void blkdev_dequeue_request(struct request *req)
680{
Tejun Heo8922e162005-10-20 16:23:44 +0200681 elv_dequeue_request(req->q, req);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700682}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700683
Linus Torvalds1da177e2005-04-16 15:20:36 -0700684/*
685 * Access functions for manipulating queue properties
686 */
Jens Axboe165125e2007-07-24 09:28:11 +0200687extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
Christoph Lameter19460892005-06-23 00:08:19 -0700688 spinlock_t *lock, int node_id);
Jens Axboe165125e2007-07-24 09:28:11 +0200689extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
690extern void blk_cleanup_queue(struct request_queue *);
691extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
692extern void blk_queue_bounce_limit(struct request_queue *, u64);
693extern void blk_queue_max_sectors(struct request_queue *, unsigned int);
694extern void blk_queue_max_phys_segments(struct request_queue *, unsigned short);
695extern void blk_queue_max_hw_segments(struct request_queue *, unsigned short);
696extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
697extern void blk_queue_hardsect_size(struct request_queue *, unsigned short);
698extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
James Bottomleyfa0ccd82008-01-10 11:30:36 -0600699extern int blk_queue_dma_drain(struct request_queue *q, void *buf,
700 unsigned int size);
Jens Axboe165125e2007-07-24 09:28:11 +0200701extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
702extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
703extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
704extern void blk_queue_dma_alignment(struct request_queue *, int);
James Bottomley11c3e682007-12-31 16:37:00 -0600705extern void blk_queue_update_dma_alignment(struct request_queue *, int);
Jens Axboe165125e2007-07-24 09:28:11 +0200706extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700707extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
Jens Axboe165125e2007-07-24 09:28:11 +0200708extern int blk_queue_ordered(struct request_queue *, unsigned, prepare_flush_fn *);
Jens Axboe165125e2007-07-24 09:28:11 +0200709extern int blk_do_ordered(struct request_queue *, struct request **);
710extern unsigned blk_ordered_cur_seq(struct request_queue *);
Tejun Heo797e7db2006-01-06 09:51:03 +0100711extern unsigned blk_ordered_req_seq(struct request *);
Jens Axboe165125e2007-07-24 09:28:11 +0200712extern void blk_ordered_complete_seq(struct request_queue *, unsigned, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700713
Jens Axboe165125e2007-07-24 09:28:11 +0200714extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700715extern void blk_dump_rq_flags(struct request *, char *);
Jens Axboe165125e2007-07-24 09:28:11 +0200716extern void generic_unplug_device(struct request_queue *);
717extern void __generic_unplug_device(struct request_queue *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700718extern long nr_blockdev_pages(void);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700719
Jens Axboe165125e2007-07-24 09:28:11 +0200720int blk_get_queue(struct request_queue *);
721struct request_queue *blk_alloc_queue(gfp_t);
722struct request_queue *blk_alloc_queue_node(gfp_t, int);
723extern void blk_put_queue(struct request_queue *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700724
725/*
726 * tag stuff
727 */
728#define blk_queue_tag_depth(q) ((q)->queue_tags->busy)
729#define blk_queue_tag_queue(q) ((q)->queue_tags->busy < (q)->queue_tags->max_depth)
Jens Axboe4aff5e22006-08-10 08:44:47 +0200730#define blk_rq_tagged(rq) ((rq)->cmd_flags & REQ_QUEUED)
Jens Axboe165125e2007-07-24 09:28:11 +0200731extern int blk_queue_start_tag(struct request_queue *, struct request *);
732extern struct request *blk_queue_find_tag(struct request_queue *, int);
733extern void blk_queue_end_tag(struct request_queue *, struct request *);
734extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *);
735extern void blk_queue_free_tags(struct request_queue *);
736extern int blk_queue_resize_tags(struct request_queue *, int);
737extern void blk_queue_invalidate_tags(struct request_queue *);
James Bottomley492dfb42006-08-30 15:48:45 -0400738extern struct blk_queue_tag *blk_init_tags(int);
739extern void blk_free_tags(struct blk_queue_tag *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700740
David C Somayajuluf583f492006-10-04 08:27:25 +0200741static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
742 int tag)
743{
744 if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
745 return NULL;
746 return bqt->tag_index[tag];
747}
748
Linus Torvalds1da177e2005-04-16 15:20:36 -0700749extern int blkdev_issue_flush(struct block_device *, sector_t *);
750
751#define MAX_PHYS_SEGMENTS 128
752#define MAX_HW_SEGMENTS 128
Mike Christiedefd94b2005-12-05 02:37:06 -0600753#define SAFE_MAX_SECTORS 255
754#define BLK_DEF_MAX_SECTORS 1024
Linus Torvalds1da177e2005-04-16 15:20:36 -0700755
756#define MAX_SEGMENT_SIZE 65536
757
758#define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
759
Jens Axboe165125e2007-07-24 09:28:11 +0200760static inline int queue_hardsect_size(struct request_queue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700761{
762 int retval = 512;
763
764 if (q && q->hardsect_size)
765 retval = q->hardsect_size;
766
767 return retval;
768}
769
770static inline int bdev_hardsect_size(struct block_device *bdev)
771{
772 return queue_hardsect_size(bdev_get_queue(bdev));
773}
774
Jens Axboe165125e2007-07-24 09:28:11 +0200775static inline int queue_dma_alignment(struct request_queue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700776{
Pete Wyckoff482eb682008-01-01 10:23:02 -0500777 return q ? q->dma_alignment : 511;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700778}
779
Linus Torvalds1da177e2005-04-16 15:20:36 -0700780/* assumes size > 256 */
781static inline unsigned int blksize_bits(unsigned int size)
782{
783 unsigned int bits = 8;
784 do {
785 bits++;
786 size >>= 1;
787 } while (size > 256);
788 return bits;
789}
790
Adrian Bunk2befb9e2005-09-10 00:27:17 -0700791static inline unsigned int block_size(struct block_device *bdev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700792{
793 return bdev->bd_block_size;
794}
795
796typedef struct {struct page *v;} Sector;
797
798unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
799
800static inline void put_dev_sector(Sector p)
801{
802 page_cache_release(p.v);
803}
804
805struct work_struct;
806int kblockd_schedule_work(struct work_struct *work);
Andrew Morton19a75d82007-05-09 02:33:56 -0700807void kblockd_flush_work(struct work_struct *work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700808
Linus Torvalds1da177e2005-04-16 15:20:36 -0700809#define MODULE_ALIAS_BLOCKDEV(major,minor) \
810 MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
811#define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
812 MODULE_ALIAS("block-major-" __stringify(major) "-*")
813
814
David Howells93614012006-09-30 20:45:40 +0200815#else /* CONFIG_BLOCK */
816/*
817 * stubs for when the block layer is configured out
818 */
819#define buffer_heads_over_limit 0
820
David Howells93614012006-09-30 20:45:40 +0200821static inline long nr_blockdev_pages(void)
822{
823 return 0;
824}
825
Andrew Mortonbcfd8d32006-08-31 12:56:06 +0200826static inline void exit_io_context(void)
827{
828}
David Howells93614012006-09-30 20:45:40 +0200829
Jens Axboe023ccde2008-01-29 14:08:06 +0100830struct io_context;
Jens Axboefd0928d2008-01-24 08:52:45 +0100831static inline int put_io_context(struct io_context *ioc)
832{
833 return 1;
834}
835
836
David Howells93614012006-09-30 20:45:40 +0200837#endif /* CONFIG_BLOCK */
838
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839#endif