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>
25 #include <linux/ioprio.h>
26
27 #ifdef CONFIG_BLOCK
28
29 #include <asm/io.h>
30
31 /* struct bio, bio_vec and BIO_* flags are defined in blk_types.h */
32 #include <linux/blk_types.h>
33
34 #define BIO_DEBUG
35
36 #ifdef BIO_DEBUG
37 #define BIO_BUG_ON BUG_ON
38 #else
39 #define BIO_BUG_ON
40 #endif
41
42 #define BIO_MAX_PAGES 256
43 #define BIO_MAX_SIZE (BIO_MAX_PAGES << PAGE_CACHE_SHIFT)
44 #define BIO_MAX_SECTORS (BIO_MAX_SIZE >> 9)
45
46 /*
47 * upper 16 bits of bi_rw define the io priority of this bio
48 */
49 #define BIO_PRIO_SHIFT (8 * sizeof(unsigned long) - IOPRIO_BITS)
50 #define bio_prio(bio) ((bio)->bi_rw >> BIO_PRIO_SHIFT)
51 #define bio_prio_valid(bio) ioprio_valid(bio_prio(bio))
52
53 #define bio_set_prio(bio, prio) do { \
54 WARN_ON(prio >= (1 << IOPRIO_BITS)); \
55 (bio)->bi_rw &= ((1UL << BIO_PRIO_SHIFT) - 1); \
56 (bio)->bi_rw |= ((unsigned long) (prio) << BIO_PRIO_SHIFT); \
57 } while (0)
58
59 /*
60 * various member access, note that bio_data should of course not be used
61 * on highmem page vectors
62 */
63 #define bio_iovec_idx(bio, idx) (&((bio)->bi_io_vec[(idx)]))
64 #define bio_iovec(bio) bio_iovec_idx((bio), (bio)->bi_idx)
65 #define bio_page(bio) bio_iovec((bio))->bv_page
66 #define bio_offset(bio) bio_iovec((bio))->bv_offset
67 #define bio_segments(bio) ((bio)->bi_vcnt - (bio)->bi_idx)
68 #define bio_sectors(bio) ((bio)->bi_size >> 9)
69
bio_cur_bytes(struct bio * bio)70 static inline unsigned int bio_cur_bytes(struct bio *bio)
71 {
72 if (bio->bi_vcnt)
73 return bio_iovec(bio)->bv_len;
74 else /* dataless requests such as discard */
75 return bio->bi_size;
76 }
77
bio_data(struct bio * bio)78 static inline void *bio_data(struct bio *bio)
79 {
80 if (bio->bi_vcnt)
81 return page_address(bio_page(bio)) + bio_offset(bio);
82
83 return NULL;
84 }
85
bio_has_allocated_vec(struct bio * bio)86 static inline int bio_has_allocated_vec(struct bio *bio)
87 {
88 return bio->bi_io_vec && bio->bi_io_vec != bio->bi_inline_vecs;
89 }
90
91 /*
92 * will die
93 */
94 #define bio_to_phys(bio) (page_to_phys(bio_page((bio))) + (unsigned long) bio_offset((bio)))
95 #define bvec_to_phys(bv) (page_to_phys((bv)->bv_page) + (unsigned long) (bv)->bv_offset)
96
97 /*
98 * queues that have highmem support enabled may still need to revert to
99 * PIO transfers occasionally and thus map high pages temporarily. For
100 * permanent PIO fall back, user is probably better off disabling highmem
101 * I/O completely on that queue (see ide-dma for example)
102 */
103 #define __bio_kmap_atomic(bio, idx, kmtype) \
104 (kmap_atomic(bio_iovec_idx((bio), (idx))->bv_page, kmtype) + \
105 bio_iovec_idx((bio), (idx))->bv_offset)
106
107 #define __bio_kunmap_atomic(addr, kmtype) kunmap_atomic(addr, kmtype)
108
109 /*
110 * merge helpers etc
111 */
112
113 #define __BVEC_END(bio) bio_iovec_idx((bio), (bio)->bi_vcnt - 1)
114 #define __BVEC_START(bio) bio_iovec_idx((bio), (bio)->bi_idx)
115
116 /* Default implementation of BIOVEC_PHYS_MERGEABLE */
117 #define __BIOVEC_PHYS_MERGEABLE(vec1, vec2) \
118 ((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2)))
119
120 /*
121 * allow arch override, for eg virtualized architectures (put in asm/io.h)
122 */
123 #ifndef BIOVEC_PHYS_MERGEABLE
124 #define BIOVEC_PHYS_MERGEABLE(vec1, vec2) \
125 __BIOVEC_PHYS_MERGEABLE(vec1, vec2)
126 #endif
127
128 #define __BIO_SEG_BOUNDARY(addr1, addr2, mask) \
129 (((addr1) | (mask)) == (((addr2) - 1) | (mask)))
130 #define BIOVEC_SEG_BOUNDARY(q, b1, b2) \
131 __BIO_SEG_BOUNDARY(bvec_to_phys((b1)), bvec_to_phys((b2)) + (b2)->bv_len, queue_segment_boundary((q)))
132 #define BIO_SEG_BOUNDARY(q, b1, b2) \
133 BIOVEC_SEG_BOUNDARY((q), __BVEC_END((b1)), __BVEC_START((b2)))
134
135 #define bio_io_error(bio) bio_endio((bio), -EIO)
136
137 /*
138 * drivers should not use the __ version unless they _really_ want to
139 * run through the entire bio and not just pending pieces
140 */
141 #define __bio_for_each_segment(bvl, bio, i, start_idx) \
142 for (bvl = bio_iovec_idx((bio), (start_idx)), i = (start_idx); \
143 i < (bio)->bi_vcnt; \
144 bvl++, i++)
145
146 #define bio_for_each_segment(bvl, bio, i) \
147 __bio_for_each_segment(bvl, bio, i, (bio)->bi_idx)
148
149 /*
150 * get a reference to a bio, so it won't disappear. the intended use is
151 * something like:
152 *
153 * bio_get(bio);
154 * submit_bio(rw, bio);
155 * if (bio->bi_flags ...)
156 * do_something
157 * bio_put(bio);
158 *
159 * without the bio_get(), it could potentially complete I/O before submit_bio
160 * returns. and then bio would be freed memory when if (bio->bi_flags ...)
161 * runs
162 */
163 #define bio_get(bio) atomic_inc(&(bio)->bi_cnt)
164
165 #if defined(CONFIG_BLK_DEV_INTEGRITY)
166 /*
167 * bio integrity payload
168 */
169 struct bio_integrity_payload {
170 struct bio *bip_bio; /* parent bio */
171
172 sector_t bip_sector; /* virtual start sector */
173
174 void *bip_buf; /* generated integrity data */
175 bio_end_io_t *bip_end_io; /* saved I/O completion fn */
176
177 unsigned int bip_size;
178
179 unsigned short bip_slab; /* slab the bip came from */
180 unsigned short bip_vcnt; /* # of integrity bio_vecs */
181 unsigned short bip_idx; /* current bip_vec index */
182
183 struct work_struct bip_work; /* I/O completion */
184 struct bio_vec bip_vec[0]; /* embedded bvec array */
185 };
186 #endif /* CONFIG_BLK_DEV_INTEGRITY */
187
188 /*
189 * A bio_pair is used when we need to split a bio.
190 * This can only happen for a bio that refers to just one
191 * page of data, and in the unusual situation when the
192 * page crosses a chunk/device boundary
193 *
194 * The address of the master bio is stored in bio1.bi_private
195 * The address of the pool the pair was allocated from is stored
196 * in bio2.bi_private
197 */
198 struct bio_pair {
199 struct bio bio1, bio2;
200 struct bio_vec bv1, bv2;
201 #if defined(CONFIG_BLK_DEV_INTEGRITY)
202 struct bio_integrity_payload bip1, bip2;
203 struct bio_vec iv1, iv2;
204 #endif
205 atomic_t cnt;
206 int error;
207 };
208 extern struct bio_pair *bio_split(struct bio *bi, int first_sectors);
209 extern void bio_pair_release(struct bio_pair *dbio);
210
211 extern struct bio_set *bioset_create(unsigned int, unsigned int);
212 extern void bioset_free(struct bio_set *);
213
214 extern struct bio *bio_alloc(gfp_t, int);
215 extern struct bio *bio_kmalloc(gfp_t, int);
216 extern struct bio *bio_alloc_bioset(gfp_t, int, struct bio_set *);
217 extern void bio_put(struct bio *);
218 extern void bio_free(struct bio *, struct bio_set *);
219
220 extern void bio_endio(struct bio *, int);
221 struct request_queue;
222 extern int bio_phys_segments(struct request_queue *, struct bio *);
223
224 extern void __bio_clone(struct bio *, struct bio *);
225 extern struct bio *bio_clone(struct bio *, gfp_t);
226
227 extern void bio_init(struct bio *);
228
229 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
230 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
231 unsigned int, unsigned int);
232 extern int bio_get_nr_vecs(struct block_device *);
233 extern sector_t bio_sector_offset(struct bio *, unsigned short, unsigned int);
234 extern struct bio *bio_map_user(struct request_queue *, struct block_device *,
235 unsigned long, unsigned int, int, gfp_t);
236 struct sg_iovec;
237 struct rq_map_data;
238 extern struct bio *bio_map_user_iov(struct request_queue *,
239 struct block_device *,
240 struct sg_iovec *, int, int, gfp_t);
241 extern void bio_unmap_user(struct bio *);
242 extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
243 gfp_t);
244 extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
245 gfp_t, int);
246 extern void bio_set_pages_dirty(struct bio *bio);
247 extern void bio_check_pages_dirty(struct bio *bio);
248
249 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
250 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
251 #endif
252 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
253 extern void bio_flush_dcache_pages(struct bio *bi);
254 #else
bio_flush_dcache_pages(struct bio * bi)255 static inline void bio_flush_dcache_pages(struct bio *bi)
256 {
257 }
258 #endif
259
260 extern struct bio *bio_copy_user(struct request_queue *, struct rq_map_data *,
261 unsigned long, unsigned int, int, gfp_t);
262 extern struct bio *bio_copy_user_iov(struct request_queue *,
263 struct rq_map_data *, struct sg_iovec *,
264 int, int, gfp_t);
265 extern int bio_uncopy_user(struct bio *);
266 void zero_fill_bio(struct bio *bio);
267 extern struct bio_vec *bvec_alloc_bs(gfp_t, int, unsigned long *, struct bio_set *);
268 extern void bvec_free_bs(struct bio_set *, struct bio_vec *, unsigned int);
269 extern unsigned int bvec_nr_vecs(unsigned short idx);
270
271 /*
272 * Allow queuer to specify a completion CPU for this bio
273 */
bio_set_completion_cpu(struct bio * bio,unsigned int cpu)274 static inline void bio_set_completion_cpu(struct bio *bio, unsigned int cpu)
275 {
276 bio->bi_comp_cpu = cpu;
277 }
278
279 /*
280 * bio_set is used to allow other portions of the IO system to
281 * allocate their own private memory pools for bio and iovec structures.
282 * These memory pools in turn all allocate from the bio_slab
283 * and the bvec_slabs[].
284 */
285 #define BIO_POOL_SIZE 2
286 #define BIOVEC_NR_POOLS 6
287 #define BIOVEC_MAX_IDX (BIOVEC_NR_POOLS - 1)
288
289 struct bio_set {
290 struct kmem_cache *bio_slab;
291 unsigned int front_pad;
292
293 mempool_t *bio_pool;
294 #if defined(CONFIG_BLK_DEV_INTEGRITY)
295 mempool_t *bio_integrity_pool;
296 #endif
297 mempool_t *bvec_pool;
298 };
299
300 struct biovec_slab {
301 int nr_vecs;
302 char *name;
303 struct kmem_cache *slab;
304 };
305
306 extern struct bio_set *fs_bio_set;
307
308 /*
309 * a small number of entries is fine, not going to be performance critical.
310 * basically we just need to survive
311 */
312 #define BIO_SPLIT_ENTRIES 2
313
314 #ifdef CONFIG_HIGHMEM
315 /*
316 * remember never ever reenable interrupts between a bvec_kmap_irq and
317 * bvec_kunmap_irq!
318 */
bvec_kmap_irq(struct bio_vec * bvec,unsigned long * flags)319 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
320 {
321 unsigned long addr;
322
323 /*
324 * might not be a highmem page, but the preempt/irq count
325 * balancing is a lot nicer this way
326 */
327 local_irq_save(*flags);
328 addr = (unsigned long) kmap_atomic(bvec->bv_page, KM_BIO_SRC_IRQ);
329
330 BUG_ON(addr & ~PAGE_MASK);
331
332 return (char *) addr + bvec->bv_offset;
333 }
334
bvec_kunmap_irq(char * buffer,unsigned long * flags)335 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
336 {
337 unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
338
339 kunmap_atomic((void *) ptr, KM_BIO_SRC_IRQ);
340 local_irq_restore(*flags);
341 }
342
343 #else
bvec_kmap_irq(struct bio_vec * bvec,unsigned long * flags)344 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
345 {
346 return page_address(bvec->bv_page) + bvec->bv_offset;
347 }
348
bvec_kunmap_irq(char * buffer,unsigned long * flags)349 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
350 {
351 *flags = 0;
352 }
353 #endif
354
__bio_kmap_irq(struct bio * bio,unsigned short idx,unsigned long * flags)355 static inline char *__bio_kmap_irq(struct bio *bio, unsigned short idx,
356 unsigned long *flags)
357 {
358 return bvec_kmap_irq(bio_iovec_idx(bio, idx), flags);
359 }
360 #define __bio_kunmap_irq(buf, flags) bvec_kunmap_irq(buf, flags)
361
362 #define bio_kmap_irq(bio, flags) \
363 __bio_kmap_irq((bio), (bio)->bi_idx, (flags))
364 #define bio_kunmap_irq(buf,flags) __bio_kunmap_irq(buf, flags)
365
366 /*
367 * Check whether this bio carries any data or not. A NULL bio is allowed.
368 */
bio_has_data(struct bio * bio)369 static inline int bio_has_data(struct bio *bio)
370 {
371 return bio && bio->bi_io_vec != NULL;
372 }
373
374 /*
375 * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
376 *
377 * A bio_list anchors a singly-linked list of bios chained through the bi_next
378 * member of the bio. The bio_list also caches the last list member to allow
379 * fast access to the tail.
380 */
381 struct bio_list {
382 struct bio *head;
383 struct bio *tail;
384 };
385
bio_list_empty(const struct bio_list * bl)386 static inline int bio_list_empty(const struct bio_list *bl)
387 {
388 return bl->head == NULL;
389 }
390
bio_list_init(struct bio_list * bl)391 static inline void bio_list_init(struct bio_list *bl)
392 {
393 bl->head = bl->tail = NULL;
394 }
395
396 #define bio_list_for_each(bio, bl) \
397 for (bio = (bl)->head; bio; bio = bio->bi_next)
398
bio_list_size(const struct bio_list * bl)399 static inline unsigned bio_list_size(const struct bio_list *bl)
400 {
401 unsigned sz = 0;
402 struct bio *bio;
403
404 bio_list_for_each(bio, bl)
405 sz++;
406
407 return sz;
408 }
409
bio_list_add(struct bio_list * bl,struct bio * bio)410 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
411 {
412 bio->bi_next = NULL;
413
414 if (bl->tail)
415 bl->tail->bi_next = bio;
416 else
417 bl->head = bio;
418
419 bl->tail = bio;
420 }
421
bio_list_add_head(struct bio_list * bl,struct bio * bio)422 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
423 {
424 bio->bi_next = bl->head;
425
426 bl->head = bio;
427
428 if (!bl->tail)
429 bl->tail = bio;
430 }
431
bio_list_merge(struct bio_list * bl,struct bio_list * bl2)432 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
433 {
434 if (!bl2->head)
435 return;
436
437 if (bl->tail)
438 bl->tail->bi_next = bl2->head;
439 else
440 bl->head = bl2->head;
441
442 bl->tail = bl2->tail;
443 }
444
bio_list_merge_head(struct bio_list * bl,struct bio_list * bl2)445 static inline void bio_list_merge_head(struct bio_list *bl,
446 struct bio_list *bl2)
447 {
448 if (!bl2->head)
449 return;
450
451 if (bl->head)
452 bl2->tail->bi_next = bl->head;
453 else
454 bl->tail = bl2->tail;
455
456 bl->head = bl2->head;
457 }
458
bio_list_peek(struct bio_list * bl)459 static inline struct bio *bio_list_peek(struct bio_list *bl)
460 {
461 return bl->head;
462 }
463
bio_list_pop(struct bio_list * bl)464 static inline struct bio *bio_list_pop(struct bio_list *bl)
465 {
466 struct bio *bio = bl->head;
467
468 if (bio) {
469 bl->head = bl->head->bi_next;
470 if (!bl->head)
471 bl->tail = NULL;
472
473 bio->bi_next = NULL;
474 }
475
476 return bio;
477 }
478
bio_list_get(struct bio_list * bl)479 static inline struct bio *bio_list_get(struct bio_list *bl)
480 {
481 struct bio *bio = bl->head;
482
483 bl->head = bl->tail = NULL;
484
485 return bio;
486 }
487
488 #if defined(CONFIG_BLK_DEV_INTEGRITY)
489
490 #define bip_vec_idx(bip, idx) (&(bip->bip_vec[(idx)]))
491 #define bip_vec(bip) bip_vec_idx(bip, 0)
492
493 #define __bip_for_each_vec(bvl, bip, i, start_idx) \
494 for (bvl = bip_vec_idx((bip), (start_idx)), i = (start_idx); \
495 i < (bip)->bip_vcnt; \
496 bvl++, i++)
497
498 #define bip_for_each_vec(bvl, bip, i) \
499 __bip_for_each_vec(bvl, bip, i, (bip)->bip_idx)
500
501 #define bio_for_each_integrity_vec(_bvl, _bio, _iter) \
502 for_each_bio(_bio) \
503 bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
504
505 #define bio_integrity(bio) (bio->bi_integrity != NULL)
506
507 extern struct bio_integrity_payload *bio_integrity_alloc_bioset(struct bio *, gfp_t, unsigned int, struct bio_set *);
508 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
509 extern void bio_integrity_free(struct bio *, struct bio_set *);
510 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
511 extern int bio_integrity_enabled(struct bio *bio);
512 extern int bio_integrity_set_tag(struct bio *, void *, unsigned int);
513 extern int bio_integrity_get_tag(struct bio *, void *, unsigned int);
514 extern int bio_integrity_prep(struct bio *);
515 extern void bio_integrity_endio(struct bio *, int);
516 extern void bio_integrity_advance(struct bio *, unsigned int);
517 extern void bio_integrity_trim(struct bio *, unsigned int, unsigned int);
518 extern void bio_integrity_split(struct bio *, struct bio_pair *, int);
519 extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t, struct bio_set *);
520 extern int bioset_integrity_create(struct bio_set *, int);
521 extern void bioset_integrity_free(struct bio_set *);
522 extern void bio_integrity_init(void);
523
524 #else /* CONFIG_BLK_DEV_INTEGRITY */
525
526 #define bio_integrity(a) (0)
527 #define bioset_integrity_create(a, b) (0)
528 #define bio_integrity_prep(a) (0)
529 #define bio_integrity_enabled(a) (0)
530 #define bio_integrity_clone(a, b, c, d) (0)
531 #define bioset_integrity_free(a) do { } while (0)
532 #define bio_integrity_free(a, b) do { } while (0)
533 #define bio_integrity_endio(a, b) do { } while (0)
534 #define bio_integrity_advance(a, b) do { } while (0)
535 #define bio_integrity_trim(a, b, c) do { } while (0)
536 #define bio_integrity_split(a, b, c) do { } while (0)
537 #define bio_integrity_set_tag(a, b, c) do { } while (0)
538 #define bio_integrity_get_tag(a, b, c) do { } while (0)
539 #define bio_integrity_init(a) do { } while (0)
540
541 #endif /* CONFIG_BLK_DEV_INTEGRITY */
542
543 #endif /* CONFIG_BLOCK */
544 #endif /* __LINUX_BIO_H */
545