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block: raid fixups for removal of bi_hw_segments
[deliverable/linux.git] / include / linux / bio.h
CommitLineData
1da177e4
LT		 1/*
2 * 2.5 block I/O model
3 *
4 * Copyright (C) 2001 Jens Axboe <axboe@suse.de>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public Licens
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
19 */
20#ifndef __LINUX_BIO_H
21#define __LINUX_BIO_H
22
23#include <linux/highmem.h>
24#include <linux/mempool.h>
22e2c507 25#include <linux/ioprio.h>
1da177e4 26
02a5e0ac
DH		 27#ifdef CONFIG_BLOCK
28
1da177e4
LT		 29#include <asm/io.h>
30
1da177e4
LT		 31#define BIO_DEBUG
32
33#ifdef BIO_DEBUG
34#define BIO_BUG_ON BUG_ON
35#else
36#define BIO_BUG_ON
37#endif
38
d84a8477 39#define BIO_MAX_PAGES 256
1da177e4
LT		 40#define BIO_MAX_SIZE (BIO_MAX_PAGES << PAGE_CACHE_SHIFT)
41#define BIO_MAX_SECTORS (BIO_MAX_SIZE >> 9)
42
43/*
44 * was unsigned short, but we might as well be ready for > 64kB I/O pages
45 */
46struct bio_vec {
47 struct page *bv_page;
48 unsigned int bv_len;
49 unsigned int bv_offset;
50};
51
52struct bio_set;
53struct bio;
7ba1ba12 54struct bio_integrity_payload;
6712ecf8 55typedef void (bio_end_io_t) (struct bio *, int);
1da177e4
LT		 56typedef void (bio_destructor_t) (struct bio *);
57
58/*
59 * main unit of I/O for the block layer and lower layers (ie drivers and
60 * stacking drivers)
61 */
62struct bio {
2c2345c2
RG		 63 sector_t bi_sector; /* device address in 512 byte
64 sectors */
1da177e4
LT		 65 struct bio *bi_next; /* request queue link */
66 struct block_device *bi_bdev;
67 unsigned long bi_flags; /* status, command, etc */
68 unsigned long bi_rw; /* bottom bits READ/WRITE,
69 * top bits priority
70 */
71
72 unsigned short bi_vcnt; /* how many bio_vec's */
73 unsigned short bi_idx; /* current index into bvl_vec */
74
75 /* Number of segments in this BIO after
76 * physical address coalescing is performed.
77 */
78 unsigned short bi_phys_segments;
79
1da177e4
LT		 80 unsigned int bi_size; /* residual I/O count */
81
1da177e4
LT		 82 unsigned int bi_max_vecs; /* max bvl_vecs we can hold */
83
84 struct bio_vec *bi_io_vec; /* the actual vec list */
85
86 bio_end_io_t *bi_end_io;
87 atomic_t bi_cnt; /* pin count */
88
89 void *bi_private;
7ba1ba12
MP		 90#if defined(CONFIG_BLK_DEV_INTEGRITY)
91 struct bio_integrity_payload *bi_integrity; /* data integrity */
92#endif
1da177e4
LT		 93
94 bio_destructor_t *bi_destructor; /* destructor */
1da177e4
LT		 95};
96
97/*
98 * bio flags
99 */
100#define BIO_UPTODATE 0 /* ok after I/O completion */
101#define BIO_RW_BLOCK 1 /* RW_AHEAD set, and read/write would block */
102#define BIO_EOF 2 /* out-out-bounds error */
5df97b91 103#define BIO_SEG_VALID 3 /* bi_phys_segments valid */
1da177e4
LT		 104#define BIO_CLONED 4 /* doesn't own data */
105#define BIO_BOUNCED 5 /* bio is a bounce bio */
106#define BIO_USER_MAPPED 6 /* contains user pages */
107#define BIO_EOPNOTSUPP 7 /* not supported */
108#define bio_flagged(bio, flag) ((bio)->bi_flags & (1 << (flag)))
109
110/*
111 * top 4 bits of bio flags indicate the pool this bio came from
112 */
113#define BIO_POOL_BITS (4)
114#define BIO_POOL_OFFSET (BITS_PER_LONG - BIO_POOL_BITS)
115#define BIO_POOL_MASK (1UL << BIO_POOL_OFFSET)
116#define BIO_POOL_IDX(bio) ((bio)->bi_flags >> BIO_POOL_OFFSET)
117
118/*
119 * bio bi_rw flags
120 *
121 * bit 0 -- read (not set) or write (set)
122 * bit 1 -- rw-ahead when set
123 * bit 2 -- barrier
124 * bit 3 -- fail fast, don't want low level driver retries
125 * bit 4 -- synchronous I/O hint: the block layer will unplug immediately
fb2dce86
DW		 126 * bit 5 -- metadata request
127 * bit 6 -- discard sectors
1da177e4 128 */
d628eaef
DW		 129#define BIO_RW 0 /* Must match RW in req flags (blkdev.h) */
130#define BIO_RW_AHEAD 1 /* Must match FAILFAST in req flags */
1da177e4
LT		 131#define BIO_RW_BARRIER 2
132#define BIO_RW_FAILFAST 3
133#define BIO_RW_SYNC 4
5404bc7a 134#define BIO_RW_META 5
fb2dce86 135#define BIO_RW_DISCARD 6
1da177e4 136
22e2c507
JA		 137/*
138 * upper 16 bits of bi_rw define the io priority of this bio
139 */
140#define BIO_PRIO_SHIFT (8 * sizeof(unsigned long) - IOPRIO_BITS)
141#define bio_prio(bio) ((bio)->bi_rw >> BIO_PRIO_SHIFT)
142#define bio_prio_valid(bio) ioprio_valid(bio_prio(bio))
143
144#define bio_set_prio(bio, prio) do { \
145 WARN_ON(prio >= (1 << IOPRIO_BITS)); \
146 (bio)->bi_rw &= ((1UL << BIO_PRIO_SHIFT) - 1); \
147 (bio)->bi_rw |= ((unsigned long) (prio) << BIO_PRIO_SHIFT); \
148} while (0)
149
1da177e4
LT		 150/*
151 * various member access, note that bio_data should of course not be used
152 * on highmem page vectors
153 */
154#define bio_iovec_idx(bio, idx) (&((bio)->bi_io_vec[(idx)]))
155#define bio_iovec(bio) bio_iovec_idx((bio), (bio)->bi_idx)
156#define bio_page(bio) bio_iovec((bio))->bv_page
157#define bio_offset(bio) bio_iovec((bio))->bv_offset
158#define bio_segments(bio) ((bio)->bi_vcnt - (bio)->bi_idx)
159#define bio_sectors(bio) ((bio)->bi_size >> 9)
1da177e4
LT		 160#define bio_barrier(bio) ((bio)->bi_rw & (1 << BIO_RW_BARRIER))
161#define bio_sync(bio) ((bio)->bi_rw & (1 << BIO_RW_SYNC))
162#define bio_failfast(bio) ((bio)->bi_rw & (1 << BIO_RW_FAILFAST))
163#define bio_rw_ahead(bio) ((bio)->bi_rw & (1 << BIO_RW_AHEAD))
5404bc7a 164#define bio_rw_meta(bio) ((bio)->bi_rw & (1 << BIO_RW_META))
fb2dce86 165#define bio_discard(bio) ((bio)->bi_rw & (1 << BIO_RW_DISCARD))
e17fc0a1 166#define bio_empty_barrier(bio) (bio_barrier(bio) && !bio_has_data(bio) && !bio_discard(bio))
bf2de6f5
JA		 167
168static inline unsigned int bio_cur_sectors(struct bio *bio)
169{
170 if (bio->bi_vcnt)
171 return bio_iovec(bio)->bv_len >> 9;
fb2dce86
DW		 172 else /* dataless requests such as discard */
173 return bio->bi_size >> 9;
bf2de6f5
JA		 174}
175
176static inline void *bio_data(struct bio *bio)
177{
178 if (bio->bi_vcnt)
179 return page_address(bio_page(bio)) + bio_offset(bio);
180
181 return NULL;
182}
1da177e4
LT		 183
184/*
185 * will die
186 */
187#define bio_to_phys(bio) (page_to_phys(bio_page((bio))) + (unsigned long) bio_offset((bio)))
188#define bvec_to_phys(bv) (page_to_phys((bv)->bv_page) + (unsigned long) (bv)->bv_offset)
189
190/*
191 * queues that have highmem support enabled may still need to revert to
192 * PIO transfers occasionally and thus map high pages temporarily. For
193 * permanent PIO fall back, user is probably better off disabling highmem
194 * I/O completely on that queue (see ide-dma for example)
195 */
196#define __bio_kmap_atomic(bio, idx, kmtype) \
197 (kmap_atomic(bio_iovec_idx((bio), (idx))->bv_page, kmtype) + \
198 bio_iovec_idx((bio), (idx))->bv_offset)
199
200#define __bio_kunmap_atomic(addr, kmtype) kunmap_atomic(addr, kmtype)
201
202/*
203 * merge helpers etc
204 */
205
206#define __BVEC_END(bio) bio_iovec_idx((bio), (bio)->bi_vcnt - 1)
207#define __BVEC_START(bio) bio_iovec_idx((bio), (bio)->bi_idx)
208
209/*
210 * allow arch override, for eg virtualized architectures (put in asm/io.h)
211 */
212#ifndef BIOVEC_PHYS_MERGEABLE
213#define BIOVEC_PHYS_MERGEABLE(vec1, vec2) \
214 ((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2)))
215#endif
216
1da177e4
LT		 217#define __BIO_SEG_BOUNDARY(addr1, addr2, mask) \
218 (((addr1) | (mask)) == (((addr2) - 1) | (mask)))
219#define BIOVEC_SEG_BOUNDARY(q, b1, b2) \
220 __BIO_SEG_BOUNDARY(bvec_to_phys((b1)), bvec_to_phys((b2)) + (b2)->bv_len, (q)->seg_boundary_mask)
221#define BIO_SEG_BOUNDARY(q, b1, b2) \
222 BIOVEC_SEG_BOUNDARY((q), __BVEC_END((b1)), __BVEC_START((b2)))
223
6712ecf8 224#define bio_io_error(bio) bio_endio((bio), -EIO)
1da177e4
LT		 225
226/*
227 * drivers should not use the __ version unless they _really_ want to
228 * run through the entire bio and not just pending pieces
229 */
230#define __bio_for_each_segment(bvl, bio, i, start_idx) \
231 for (bvl = bio_iovec_idx((bio), (start_idx)), i = (start_idx); \
232 i < (bio)->bi_vcnt; \
233 bvl++, i++)
234
235#define bio_for_each_segment(bvl, bio, i) \
236 __bio_for_each_segment(bvl, bio, i, (bio)->bi_idx)
237
238/*
239 * get a reference to a bio, so it won't disappear. the intended use is
240 * something like:
241 *
242 * bio_get(bio);
243 * submit_bio(rw, bio);
244 * if (bio->bi_flags ...)
245 * do_something
246 * bio_put(bio);
247 *
248 * without the bio_get(), it could potentially complete I/O before submit_bio
249 * returns. and then bio would be freed memory when if (bio->bi_flags ...)
250 * runs
251 */
252#define bio_get(bio) atomic_inc(&(bio)->bi_cnt)
253
7ba1ba12
MP		 254#if defined(CONFIG_BLK_DEV_INTEGRITY)
255/*
256 * bio integrity payload
257 */
258struct bio_integrity_payload {
259 struct bio *bip_bio; /* parent bio */
260 struct bio_vec *bip_vec; /* integrity data vector */
261
262 sector_t bip_sector; /* virtual start sector */
263
264 void *bip_buf; /* generated integrity data */
265 bio_end_io_t *bip_end_io; /* saved I/O completion fn */
266
267 int bip_error; /* saved I/O error */
268 unsigned int bip_size;
269
270 unsigned short bip_pool; /* pool the ivec came from */
271 unsigned short bip_vcnt; /* # of integrity bio_vecs */
272 unsigned short bip_idx; /* current bip_vec index */
273
274 struct work_struct bip_work; /* I/O completion */
275};
276#endif /* CONFIG_BLK_DEV_INTEGRITY */
1da177e4
LT		 277
278/*
279 * A bio_pair is used when we need to split a bio.
280 * This can only happen for a bio that refers to just one
281 * page of data, and in the unusual situation when the
282 * page crosses a chunk/device boundary
283 *
284 * The address of the master bio is stored in bio1.bi_private
285 * The address of the pool the pair was allocated from is stored
286 * in bio2.bi_private
287 */
288struct bio_pair {
7ba1ba12
MP		 289 struct bio bio1, bio2;
290 struct bio_vec bv1, bv2;
291#if defined(CONFIG_BLK_DEV_INTEGRITY)
292 struct bio_integrity_payload bip1, bip2;
293 struct bio_vec iv1, iv2;
294#endif
295 atomic_t cnt;
296 int error;
1da177e4
LT		 297};
298extern struct bio_pair *bio_split(struct bio *bi, mempool_t *pool,
299 int first_sectors);
300extern mempool_t *bio_split_pool;
301extern void bio_pair_release(struct bio_pair *dbio);
302
5972511b 303extern struct bio_set *bioset_create(int, int);
1da177e4
LT		 304extern void bioset_free(struct bio_set *);
305
dd0fc66f
AV		 306extern struct bio *bio_alloc(gfp_t, int);
307extern struct bio *bio_alloc_bioset(gfp_t, int, struct bio_set *);
1da177e4 308extern void bio_put(struct bio *);
3676347a 309extern void bio_free(struct bio *, struct bio_set *);
1da177e4 310
6712ecf8 311extern void bio_endio(struct bio *, int);
1da177e4
LT		 312struct request_queue;
313extern int bio_phys_segments(struct request_queue *, struct bio *);
1da177e4
LT		 314
315extern void __bio_clone(struct bio *, struct bio *);
dd0fc66f 316extern struct bio *bio_clone(struct bio *, gfp_t);
1da177e4
LT		 317
318extern void bio_init(struct bio *);
319
320extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
6e68af66
MC		 321extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
322 unsigned int, unsigned int);
1da177e4
LT		 323extern int bio_get_nr_vecs(struct block_device *);
324extern struct bio *bio_map_user(struct request_queue *, struct block_device *,
325 unsigned long, unsigned int, int);
f1970baf
JB		 326struct sg_iovec;
327extern struct bio *bio_map_user_iov(struct request_queue *,
328 struct block_device *,
329 struct sg_iovec *, int, int);
1da177e4 330extern void bio_unmap_user(struct bio *);
df46b9a4 331extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
27496a8c 332 gfp_t);
68154e90
FT		 333extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
334 gfp_t, int);
1da177e4
LT		 335extern void bio_set_pages_dirty(struct bio *bio);
336extern void bio_check_pages_dirty(struct bio *bio);
337extern struct bio *bio_copy_user(struct request_queue *, unsigned long, unsigned int, int);
c5dec1c3
FT		 338extern struct bio *bio_copy_user_iov(struct request_queue *, struct sg_iovec *,
339 int, int);
1da177e4
LT		 340extern int bio_uncopy_user(struct bio *);
341void zero_fill_bio(struct bio *bio);
51d654e1 342extern struct bio_vec *bvec_alloc_bs(gfp_t, int, unsigned long *, struct bio_set *);
7ba1ba12 343extern unsigned int bvec_nr_vecs(unsigned short idx);
51d654e1
MP		 344
345/*
346 * bio_set is used to allow other portions of the IO system to
347 * allocate their own private memory pools for bio and iovec structures.
348 * These memory pools in turn all allocate from the bio_slab
349 * and the bvec_slabs[].
350 */
351#define BIO_POOL_SIZE 2
352#define BIOVEC_NR_POOLS 6
353
354struct bio_set {
355 mempool_t *bio_pool;
7ba1ba12
MP		 356#if defined(CONFIG_BLK_DEV_INTEGRITY)
357 mempool_t *bio_integrity_pool;
358#endif
51d654e1
MP		 359 mempool_t *bvec_pools[BIOVEC_NR_POOLS];
360};
361
362struct biovec_slab {
363 int nr_vecs;
364 char *name;
365 struct kmem_cache *slab;
366};
367
368extern struct bio_set *fs_bio_set;
369
370/*
371 * a small number of entries is fine, not going to be performance critical.
372 * basically we just need to survive
373 */
374#define BIO_SPLIT_ENTRIES 2
1da177e4
LT		 375
376#ifdef CONFIG_HIGHMEM
377/*
378 * remember to add offset! and never ever reenable interrupts between a
379 * bvec_kmap_irq and bvec_kunmap_irq!!
380 *
381 * This function MUST be inlined - it plays with the CPU interrupt flags.
1da177e4 382 */
c2d08dad 383static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
1da177e4
LT		 384{
385 unsigned long addr;
386
387 /*
388 * might not be a highmem page, but the preempt/irq count
389 * balancing is a lot nicer this way
390 */
391 local_irq_save(*flags);
392 addr = (unsigned long) kmap_atomic(bvec->bv_page, KM_BIO_SRC_IRQ);
393
394 BUG_ON(addr & ~PAGE_MASK);
395
396 return (char *) addr + bvec->bv_offset;
397}
398
c2d08dad 399static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
1da177e4
LT		 400{
401 unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
402
403 kunmap_atomic((void *) ptr, KM_BIO_SRC_IRQ);
404 local_irq_restore(*flags);
405}
406
407#else
408#define bvec_kmap_irq(bvec, flags) (page_address((bvec)->bv_page) + (bvec)->bv_offset)
409#define bvec_kunmap_irq(buf, flags) do { *(flags) = 0; } while (0)
410#endif
411
c2d08dad 412static inline char *__bio_kmap_irq(struct bio *bio, unsigned short idx,
1da177e4
LT		 413 unsigned long *flags)
414{
415 return bvec_kmap_irq(bio_iovec_idx(bio, idx), flags);
416}
417#define __bio_kunmap_irq(buf, flags) bvec_kunmap_irq(buf, flags)
418
419#define bio_kmap_irq(bio, flags) \
420 __bio_kmap_irq((bio), (bio)->bi_idx, (flags))
421#define bio_kunmap_irq(buf,flags) __bio_kunmap_irq(buf, flags)
422
7a67f63b
JA		 423/*
424 * Check whether this bio carries any data or not. A NULL bio is allowed.
425 */
426static inline int bio_has_data(struct bio *bio)
427{
428 return bio && bio->bi_io_vec != NULL;
429}
430
7ba1ba12
MP		 431#if defined(CONFIG_BLK_DEV_INTEGRITY)
432
433#define bip_vec_idx(bip, idx) (&(bip->bip_vec[(idx)]))
434#define bip_vec(bip) bip_vec_idx(bip, 0)
435
436#define __bip_for_each_vec(bvl, bip, i, start_idx) \
437 for (bvl = bip_vec_idx((bip), (start_idx)), i = (start_idx); \
438 i < (bip)->bip_vcnt; \
439 bvl++, i++)
440
441#define bip_for_each_vec(bvl, bip, i) \
442 __bip_for_each_vec(bvl, bip, i, (bip)->bip_idx)
443
6e2401ad
JA		 444static inline int bio_integrity(struct bio *bio)
445{
446#if defined(CONFIG_BLK_DEV_INTEGRITY)
447 return bio->bi_integrity != NULL;
448#else
449 return 0;
450#endif
451}
7ba1ba12
MP		 452
453extern struct bio_integrity_payload *bio_integrity_alloc_bioset(struct bio *, gfp_t, unsigned int, struct bio_set *);
454extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
455extern void bio_integrity_free(struct bio *, struct bio_set *);
456extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
457extern int bio_integrity_enabled(struct bio *bio);
458extern int bio_integrity_set_tag(struct bio *, void *, unsigned int);
459extern int bio_integrity_get_tag(struct bio *, void *, unsigned int);
460extern int bio_integrity_prep(struct bio *);
461extern void bio_integrity_endio(struct bio *, int);
462extern void bio_integrity_advance(struct bio *, unsigned int);
463extern void bio_integrity_trim(struct bio *, unsigned int, unsigned int);
464extern void bio_integrity_split(struct bio *, struct bio_pair *, int);
465extern int bio_integrity_clone(struct bio *, struct bio *, struct bio_set *);
466extern int bioset_integrity_create(struct bio_set *, int);
467extern void bioset_integrity_free(struct bio_set *);
468extern void bio_integrity_init_slab(void);
469
470#else /* CONFIG_BLK_DEV_INTEGRITY */
471
472#define bio_integrity(a) (0)
473#define bioset_integrity_create(a, b) (0)
474#define bio_integrity_prep(a) (0)
475#define bio_integrity_enabled(a) (0)
476#define bio_integrity_clone(a, b, c) (0)
477#define bioset_integrity_free(a) do { } while (0)
478#define bio_integrity_free(a, b) do { } while (0)
479#define bio_integrity_endio(a, b) do { } while (0)
480#define bio_integrity_advance(a, b) do { } while (0)
481#define bio_integrity_trim(a, b, c) do { } while (0)
482#define bio_integrity_split(a, b, c) do { } while (0)
483#define bio_integrity_set_tag(a, b, c) do { } while (0)
484#define bio_integrity_get_tag(a, b, c) do { } while (0)
485#define bio_integrity_init_slab(a) do { } while (0)
486
487#endif /* CONFIG_BLK_DEV_INTEGRITY */
488
02a5e0ac 489#endif /* CONFIG_BLOCK */
1da177e4 490#endif /* __LINUX_BIO_H */
Linux kernel - Deliverables
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