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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
70static 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
78static 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
86static 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 */
169struct 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 */
198struct 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};
208extern struct bio_pair *bio_split(struct bio *bi, int first_sectors);
209extern void bio_pair_release(struct bio_pair *dbio);
210
211extern struct bio_set *bioset_create(unsigned int, unsigned int);
212extern void bioset_free(struct bio_set *);
213
214extern struct bio *bio_alloc(gfp_t, unsigned int);
215extern struct bio *bio_kmalloc(gfp_t, unsigned int);
216extern struct bio *bio_alloc_bioset(gfp_t, int, struct bio_set *);
217extern void bio_put(struct bio *);
218extern void bio_free(struct bio *, struct bio_set *);
219
220extern void bio_endio(struct bio *, int);
221struct request_queue;
222extern int bio_phys_segments(struct request_queue *, struct bio *);
223
224extern void __bio_clone(struct bio *, struct bio *);
225extern struct bio *bio_clone(struct bio *, gfp_t);
226
227extern void bio_init(struct bio *);
228
229extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
230extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
231 unsigned int, unsigned int);
232extern int bio_get_nr_vecs(struct block_device *);
233extern sector_t bio_sector_offset(struct bio *, unsigned short, unsigned int);
234extern struct bio *bio_map_user(struct request_queue *, struct block_device *,
235 unsigned long, unsigned int, int, gfp_t);
236struct sg_iovec;
237struct rq_map_data;
238extern struct bio *bio_map_user_iov(struct request_queue *,
239 struct block_device *,
240 struct sg_iovec *, int, int, gfp_t);
241extern void bio_unmap_user(struct bio *);
242extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
243 gfp_t);
244extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
245 gfp_t, int);
246extern void bio_set_pages_dirty(struct bio *bio);
247extern 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
253extern void bio_flush_dcache_pages(struct bio *bi);
254#else
255static inline void bio_flush_dcache_pages(struct bio *bi)
256{
257}
258#endif
259
260extern struct bio *bio_copy_user(struct request_queue *, struct rq_map_data *,
261 unsigned long, unsigned int, int, gfp_t);
262extern struct bio *bio_copy_user_iov(struct request_queue *,
263 struct rq_map_data *, struct sg_iovec *,
264 int, int, gfp_t);
265extern int bio_uncopy_user(struct bio *);
266void zero_fill_bio(struct bio *bio);
267extern struct bio_vec *bvec_alloc_bs(gfp_t, int, unsigned long *, struct bio_set *);
268extern void bvec_free_bs(struct bio_set *, struct bio_vec *, unsigned int);
269extern unsigned int bvec_nr_vecs(unsigned short idx);
270
271/*
272 * bio_set is used to allow other portions of the IO system to
273 * allocate their own private memory pools for bio and iovec structures.
274 * These memory pools in turn all allocate from the bio_slab
275 * and the bvec_slabs[].
276 */
277#define BIO_POOL_SIZE 2
278#define BIOVEC_NR_POOLS 6
279#define BIOVEC_MAX_IDX (BIOVEC_NR_POOLS - 1)
280
281struct bio_set {
282 struct kmem_cache *bio_slab;
283 unsigned int front_pad;
284
285 mempool_t *bio_pool;
286#if defined(CONFIG_BLK_DEV_INTEGRITY)
287 mempool_t *bio_integrity_pool;
288#endif
289 mempool_t *bvec_pool;
290};
291
292struct biovec_slab {
293 int nr_vecs;
294 char *name;
295 struct kmem_cache *slab;
296};
297
298extern struct bio_set *fs_bio_set;
299
300/*
301 * a small number of entries is fine, not going to be performance critical.
302 * basically we just need to survive
303 */
304#define BIO_SPLIT_ENTRIES 2
305
306#ifdef CONFIG_HIGHMEM
307/*
308 * remember never ever reenable interrupts between a bvec_kmap_irq and
309 * bvec_kunmap_irq!
310 */
311static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
312{
313 unsigned long addr;
314
315 /*
316 * might not be a highmem page, but the preempt/irq count
317 * balancing is a lot nicer this way
318 */
319 local_irq_save(*flags);
320 addr = (unsigned long) kmap_atomic(bvec->bv_page, KM_BIO_SRC_IRQ);
321
322 BUG_ON(addr & ~PAGE_MASK);
323
324 return (char *) addr + bvec->bv_offset;
325}
326
327static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
328{
329 unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
330
331 kunmap_atomic((void *) ptr, KM_BIO_SRC_IRQ);
332 local_irq_restore(*flags);
333}
334
335#else
336static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
337{
338 return page_address(bvec->bv_page) + bvec->bv_offset;
339}
340
341static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
342{
343 *flags = 0;
344}
345#endif
346
347static inline char *__bio_kmap_irq(struct bio *bio, unsigned short idx,
348 unsigned long *flags)
349{
350 return bvec_kmap_irq(bio_iovec_idx(bio, idx), flags);
351}
352#define __bio_kunmap_irq(buf, flags) bvec_kunmap_irq(buf, flags)
353
354#define bio_kmap_irq(bio, flags) \
355 __bio_kmap_irq((bio), (bio)->bi_idx, (flags))
356#define bio_kunmap_irq(buf,flags) __bio_kunmap_irq(buf, flags)
357
358/*
359 * Check whether this bio carries any data or not. A NULL bio is allowed.
360 */
361static inline int bio_has_data(struct bio *bio)
362{
363 return bio && bio->bi_io_vec != NULL;
364}
365
366/*
367 * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
368 *
369 * A bio_list anchors a singly-linked list of bios chained through the bi_next
370 * member of the bio. The bio_list also caches the last list member to allow
371 * fast access to the tail.
372 */
373struct bio_list {
374 struct bio *head;
375 struct bio *tail;
376};
377
378static inline int bio_list_empty(const struct bio_list *bl)
379{
380 return bl->head == NULL;
381}
382
383static inline void bio_list_init(struct bio_list *bl)
384{
385 bl->head = bl->tail = NULL;
386}
387
388#define bio_list_for_each(bio, bl) \
389 for (bio = (bl)->head; bio; bio = bio->bi_next)
390
391static inline unsigned bio_list_size(const struct bio_list *bl)
392{
393 unsigned sz = 0;
394 struct bio *bio;
395
396 bio_list_for_each(bio, bl)
397 sz++;
398
399 return sz;
400}
401
402static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
403{
404 bio->bi_next = NULL;
405
406 if (bl->tail)
407 bl->tail->bi_next = bio;
408 else
409 bl->head = bio;
410
411 bl->tail = bio;
412}
413
414static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
415{
416 bio->bi_next = bl->head;
417
418 bl->head = bio;
419
420 if (!bl->tail)
421 bl->tail = bio;
422}
423
424static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
425{
426 if (!bl2->head)
427 return;
428
429 if (bl->tail)
430 bl->tail->bi_next = bl2->head;
431 else
432 bl->head = bl2->head;
433
434 bl->tail = bl2->tail;
435}
436
437static inline void bio_list_merge_head(struct bio_list *bl,
438 struct bio_list *bl2)
439{
440 if (!bl2->head)
441 return;
442
443 if (bl->head)
444 bl2->tail->bi_next = bl->head;
445 else
446 bl->tail = bl2->tail;
447
448 bl->head = bl2->head;
449}
450
451static inline struct bio *bio_list_peek(struct bio_list *bl)
452{
453 return bl->head;
454}
455
456static inline struct bio *bio_list_pop(struct bio_list *bl)
457{
458 struct bio *bio = bl->head;
459
460 if (bio) {
461 bl->head = bl->head->bi_next;
462 if (!bl->head)
463 bl->tail = NULL;
464
465 bio->bi_next = NULL;
466 }
467
468 return bio;
469}
470
471static inline struct bio *bio_list_get(struct bio_list *bl)
472{
473 struct bio *bio = bl->head;
474
475 bl->head = bl->tail = NULL;
476
477 return bio;
478}
479
480#if defined(CONFIG_BLK_DEV_INTEGRITY)
481
482#define bip_vec_idx(bip, idx) (&(bip->bip_vec[(idx)]))
483#define bip_vec(bip) bip_vec_idx(bip, 0)
484
485#define __bip_for_each_vec(bvl, bip, i, start_idx) \
486 for (bvl = bip_vec_idx((bip), (start_idx)), i = (start_idx); \
487 i < (bip)->bip_vcnt; \
488 bvl++, i++)
489
490#define bip_for_each_vec(bvl, bip, i) \
491 __bip_for_each_vec(bvl, bip, i, (bip)->bip_idx)
492
493#define bio_for_each_integrity_vec(_bvl, _bio, _iter) \
494 for_each_bio(_bio) \
495 bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
496
497#define bio_integrity(bio) (bio->bi_integrity != NULL)
498
499extern struct bio_integrity_payload *bio_integrity_alloc_bioset(struct bio *, gfp_t, unsigned int, struct bio_set *);
500extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
501extern void bio_integrity_free(struct bio *, struct bio_set *);
502extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
503extern int bio_integrity_enabled(struct bio *bio);
504extern int bio_integrity_set_tag(struct bio *, void *, unsigned int);
505extern int bio_integrity_get_tag(struct bio *, void *, unsigned int);
506extern int bio_integrity_prep(struct bio *);
507extern void bio_integrity_endio(struct bio *, int);
508extern void bio_integrity_advance(struct bio *, unsigned int);
509extern void bio_integrity_trim(struct bio *, unsigned int, unsigned int);
510extern void bio_integrity_split(struct bio *, struct bio_pair *, int);
511extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t, struct bio_set *);
512extern int bioset_integrity_create(struct bio_set *, int);
513extern void bioset_integrity_free(struct bio_set *);
514extern void bio_integrity_init(void);
515
516#else /* CONFIG_BLK_DEV_INTEGRITY */
517
518#define bio_integrity(a) (0)
519#define bioset_integrity_create(a, b) (0)
520#define bio_integrity_prep(a) (0)
521#define bio_integrity_enabled(a) (0)
522static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
523 gfp_t gfp_mask, struct bio_set *bs)
524{
525 return 0;
526}
527#define bioset_integrity_free(a) do { } while (0)
528#define bio_integrity_free(a, b) do { } while (0)
529#define bio_integrity_endio(a, b) do { } while (0)
530#define bio_integrity_advance(a, b) do { } while (0)
531#define bio_integrity_trim(a, b, c) do { } while (0)
532#define bio_integrity_split(a, b, c) do { } while (0)
533#define bio_integrity_set_tag(a, b, c) do { } while (0)
534#define bio_integrity_get_tag(a, b, c) do { } while (0)
535#define bio_integrity_init(a) do { } while (0)
536
537#endif /* CONFIG_BLK_DEV_INTEGRITY */
538
539#endif /* CONFIG_BLOCK */
540#endif /* __LINUX_BIO_H */