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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#include <linux/bug.h>
27
28#ifdef CONFIG_BLOCK
29
30#include <asm/io.h>
31
32/* struct bio, bio_vec and BIO_* flags are defined in blk_types.h */
33#include <linux/blk_types.h>
34
35#define BIO_DEBUG
36
37#ifdef BIO_DEBUG
38#define BIO_BUG_ON BUG_ON
39#else
40#define BIO_BUG_ON
41#endif
42
43#define BIO_MAX_PAGES 256
44#define BIO_MAX_SIZE (BIO_MAX_PAGES << PAGE_CACHE_SHIFT)
45#define BIO_MAX_SECTORS (BIO_MAX_SIZE >> 9)
46
47/*
48 * upper 16 bits of bi_rw define the io priority of this bio
49 */
50#define BIO_PRIO_SHIFT (8 * sizeof(unsigned long) - IOPRIO_BITS)
51#define bio_prio(bio) ((bio)->bi_rw >> BIO_PRIO_SHIFT)
52#define bio_prio_valid(bio) ioprio_valid(bio_prio(bio))
53
54#define bio_set_prio(bio, prio) do { \
55 WARN_ON(prio >= (1 << IOPRIO_BITS)); \
56 (bio)->bi_rw &= ((1UL << BIO_PRIO_SHIFT) - 1); \
57 (bio)->bi_rw |= ((unsigned long) (prio) << BIO_PRIO_SHIFT); \
58} while (0)
59
60/*
61 * various member access, note that bio_data should of course not be used
62 * on highmem page vectors
63 */
64#define bio_iovec_idx(bio, idx) (&((bio)->bi_io_vec[(idx)]))
65#define bio_iovec(bio) bio_iovec_idx((bio), (bio)->bi_idx)
66#define bio_page(bio) bio_iovec((bio))->bv_page
67#define bio_offset(bio) bio_iovec((bio))->bv_offset
68#define bio_segments(bio) ((bio)->bi_vcnt - (bio)->bi_idx)
69#define bio_sectors(bio) ((bio)->bi_size >> 9)
70
71static inline unsigned int bio_cur_bytes(struct bio *bio)
72{
73 if (bio->bi_vcnt)
74 return bio_iovec(bio)->bv_len;
75 else /* dataless requests such as discard */
76 return bio->bi_size;
77}
78
79static inline void *bio_data(struct bio *bio)
80{
81 if (bio->bi_vcnt)
82 return page_address(bio_page(bio)) + bio_offset(bio);
83
84 return NULL;
85}
86
87static inline int bio_has_allocated_vec(struct bio *bio)
88{
89 return bio->bi_io_vec && bio->bi_io_vec != bio->bi_inline_vecs;
90}
91
92/*
93 * will die
94 */
95#define bio_to_phys(bio) (page_to_phys(bio_page((bio))) + (unsigned long) bio_offset((bio)))
96#define bvec_to_phys(bv) (page_to_phys((bv)->bv_page) + (unsigned long) (bv)->bv_offset)
97
98/*
99 * queues that have highmem support enabled may still need to revert to
100 * PIO transfers occasionally and thus map high pages temporarily. For
101 * permanent PIO fall back, user is probably better off disabling highmem
102 * I/O completely on that queue (see ide-dma for example)
103 */
104#define __bio_kmap_atomic(bio, idx, kmtype) \
105 (kmap_atomic(bio_iovec_idx((bio), (idx))->bv_page) + \
106 bio_iovec_idx((bio), (idx))->bv_offset)
107
108#define __bio_kunmap_atomic(addr, kmtype) kunmap_atomic(addr)
109
110/*
111 * merge helpers etc
112 */
113
114#define __BVEC_END(bio) bio_iovec_idx((bio), (bio)->bi_vcnt - 1)
115#define __BVEC_START(bio) bio_iovec_idx((bio), (bio)->bi_idx)
116
117/* Default implementation of BIOVEC_PHYS_MERGEABLE */
118#define __BIOVEC_PHYS_MERGEABLE(vec1, vec2) \
119 ((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2)))
120
121/*
122 * allow arch override, for eg virtualized architectures (put in asm/io.h)
123 */
124#ifndef BIOVEC_PHYS_MERGEABLE
125#define BIOVEC_PHYS_MERGEABLE(vec1, vec2) \
126 __BIOVEC_PHYS_MERGEABLE(vec1, vec2)
127#endif
128
129#define __BIO_SEG_BOUNDARY(addr1, addr2, mask) \
130 (((addr1) | (mask)) == (((addr2) - 1) | (mask)))
131#define BIOVEC_SEG_BOUNDARY(q, b1, b2) \
132 __BIO_SEG_BOUNDARY(bvec_to_phys((b1)), bvec_to_phys((b2)) + (b2)->bv_len, queue_segment_boundary((q)))
133#define BIO_SEG_BOUNDARY(q, b1, b2) \
134 BIOVEC_SEG_BOUNDARY((q), __BVEC_END((b1)), __BVEC_START((b2)))
135
136#define bio_io_error(bio) bio_endio((bio), -EIO)
137
138/*
139 * drivers should not use the __ version unless they _really_ want to
140 * run through the entire bio and not just pending pieces
141 */
142#define __bio_for_each_segment(bvl, bio, i, start_idx) \
143 for (bvl = bio_iovec_idx((bio), (start_idx)), i = (start_idx); \
144 i < (bio)->bi_vcnt; \
145 bvl++, i++)
146
147#define bio_for_each_segment(bvl, bio, i) \
148 __bio_for_each_segment(bvl, bio, i, (bio)->bi_idx)
149
150/*
151 * get a reference to a bio, so it won't disappear. the intended use is
152 * something like:
153 *
154 * bio_get(bio);
155 * submit_bio(rw, bio);
156 * if (bio->bi_flags ...)
157 * do_something
158 * bio_put(bio);
159 *
160 * without the bio_get(), it could potentially complete I/O before submit_bio
161 * returns. and then bio would be freed memory when if (bio->bi_flags ...)
162 * runs
163 */
164#define bio_get(bio) atomic_inc(&(bio)->bi_cnt)
165
166#if defined(CONFIG_BLK_DEV_INTEGRITY)
167/*
168 * bio integrity payload
169 */
170struct bio_integrity_payload {
171 struct bio *bip_bio; /* parent bio */
172
173 sector_t bip_sector; /* virtual start sector */
174
175 void *bip_buf; /* generated integrity data */
176 bio_end_io_t *bip_end_io; /* saved I/O completion fn */
177
178 unsigned int bip_size;
179
180 unsigned short bip_slab; /* slab the bip came from */
181 unsigned short bip_vcnt; /* # of integrity bio_vecs */
182 unsigned short bip_idx; /* current bip_vec index */
183
184 struct work_struct bip_work; /* I/O completion */
185 struct bio_vec bip_vec[0]; /* embedded bvec array */
186};
187#endif /* CONFIG_BLK_DEV_INTEGRITY */
188
189/*
190 * A bio_pair is used when we need to split a bio.
191 * This can only happen for a bio that refers to just one
192 * page of data, and in the unusual situation when the
193 * page crosses a chunk/device boundary
194 *
195 * The address of the master bio is stored in bio1.bi_private
196 * The address of the pool the pair was allocated from is stored
197 * in bio2.bi_private
198 */
199struct bio_pair {
200 struct bio bio1, bio2;
201 struct bio_vec bv1, bv2;
202#if defined(CONFIG_BLK_DEV_INTEGRITY)
203 struct bio_integrity_payload bip1, bip2;
204 struct bio_vec iv1, iv2;
205#endif
206 atomic_t cnt;
207 int error;
208};
209extern struct bio_pair *bio_split(struct bio *bi, int first_sectors);
210extern void bio_pair_release(struct bio_pair *dbio);
211
212extern struct bio_set *bioset_create(unsigned int, unsigned int);
213extern void bioset_free(struct bio_set *);
214
215extern struct bio *bio_alloc(gfp_t, unsigned int);
216extern struct bio *bio_kmalloc(gfp_t, unsigned int);
217extern struct bio *bio_alloc_bioset(gfp_t, int, struct bio_set *);
218extern void bio_put(struct bio *);
219extern void bio_free(struct bio *, struct bio_set *);
220
221extern void bio_endio(struct bio *, int);
222struct request_queue;
223extern int bio_phys_segments(struct request_queue *, struct bio *);
224
225extern void __bio_clone(struct bio *, struct bio *);
226extern struct bio *bio_clone(struct bio *, gfp_t);
227
228extern void bio_init(struct bio *);
229
230extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
231extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
232 unsigned int, unsigned int);
233extern int bio_get_nr_vecs(struct block_device *);
234extern sector_t bio_sector_offset(struct bio *, unsigned short, unsigned int);
235extern struct bio *bio_map_user(struct request_queue *, struct block_device *,
236 unsigned long, unsigned int, int, gfp_t);
237struct sg_iovec;
238struct rq_map_data;
239extern struct bio *bio_map_user_iov(struct request_queue *,
240 struct block_device *,
241 struct sg_iovec *, int, int, gfp_t);
242extern void bio_unmap_user(struct bio *);
243extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
244 gfp_t);
245extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
246 gfp_t, int);
247extern void bio_set_pages_dirty(struct bio *bio);
248extern void bio_check_pages_dirty(struct bio *bio);
249
250#ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
251# error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
252#endif
253#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
254extern void bio_flush_dcache_pages(struct bio *bi);
255#else
256static inline void bio_flush_dcache_pages(struct bio *bi)
257{
258}
259#endif
260
261extern struct bio *bio_copy_user(struct request_queue *, struct rq_map_data *,
262 unsigned long, unsigned int, int, gfp_t);
263extern struct bio *bio_copy_user_iov(struct request_queue *,
264 struct rq_map_data *, struct sg_iovec *,
265 int, int, gfp_t);
266extern int bio_uncopy_user(struct bio *);
267void zero_fill_bio(struct bio *bio);
268extern struct bio_vec *bvec_alloc_bs(gfp_t, int, unsigned long *, struct bio_set *);
269extern void bvec_free_bs(struct bio_set *, struct bio_vec *, unsigned int);
270extern unsigned int bvec_nr_vecs(unsigned short idx);
271
272#ifdef CONFIG_BLK_CGROUP
273int bio_associate_current(struct bio *bio);
274void bio_disassociate_task(struct bio *bio);
275#else /* CONFIG_BLK_CGROUP */
276static inline int bio_associate_current(struct bio *bio) { return -ENOENT; }
277static inline void bio_disassociate_task(struct bio *bio) { }
278#endif /* CONFIG_BLK_CGROUP */
279
280/*
281 * bio_set is used to allow other portions of the IO system to
282 * allocate their own private memory pools for bio and iovec structures.
283 * These memory pools in turn all allocate from the bio_slab
284 * and the bvec_slabs[].
285 */
286#define BIO_POOL_SIZE 2
287#define BIOVEC_NR_POOLS 6
288#define BIOVEC_MAX_IDX (BIOVEC_NR_POOLS - 1)
289
290struct bio_set {
291 struct kmem_cache *bio_slab;
292 unsigned int front_pad;
293
294 mempool_t *bio_pool;
295#if defined(CONFIG_BLK_DEV_INTEGRITY)
296 mempool_t *bio_integrity_pool;
297#endif
298 mempool_t *bvec_pool;
299};
300
301struct biovec_slab {
302 int nr_vecs;
303 char *name;
304 struct kmem_cache *slab;
305};
306
307extern struct bio_set *fs_bio_set;
308
309/*
310 * a small number of entries is fine, not going to be performance critical.
311 * basically we just need to survive
312 */
313#define BIO_SPLIT_ENTRIES 2
314
315#ifdef CONFIG_HIGHMEM
316/*
317 * remember never ever reenable interrupts between a bvec_kmap_irq and
318 * bvec_kunmap_irq!
319 */
320static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
321{
322 unsigned long addr;
323
324 /*
325 * might not be a highmem page, but the preempt/irq count
326 * balancing is a lot nicer this way
327 */
328 local_irq_save(*flags);
329 addr = (unsigned long) kmap_atomic(bvec->bv_page);
330
331 BUG_ON(addr & ~PAGE_MASK);
332
333 return (char *) addr + bvec->bv_offset;
334}
335
336static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
337{
338 unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
339
340 kunmap_atomic((void *) ptr);
341 local_irq_restore(*flags);
342}
343
344#else
345static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
346{
347 return page_address(bvec->bv_page) + bvec->bv_offset;
348}
349
350static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
351{
352 *flags = 0;
353}
354#endif
355
356static inline char *__bio_kmap_irq(struct bio *bio, unsigned short idx,
357 unsigned long *flags)
358{
359 return bvec_kmap_irq(bio_iovec_idx(bio, idx), flags);
360}
361#define __bio_kunmap_irq(buf, flags) bvec_kunmap_irq(buf, flags)
362
363#define bio_kmap_irq(bio, flags) \
364 __bio_kmap_irq((bio), (bio)->bi_idx, (flags))
365#define bio_kunmap_irq(buf,flags) __bio_kunmap_irq(buf, flags)
366
367/*
368 * Check whether this bio carries any data or not. A NULL bio is allowed.
369 */
370static inline int bio_has_data(struct bio *bio)
371{
372 return bio && bio->bi_io_vec != NULL;
373}
374
375/*
376 * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
377 *
378 * A bio_list anchors a singly-linked list of bios chained through the bi_next
379 * member of the bio. The bio_list also caches the last list member to allow
380 * fast access to the tail.
381 */
382struct bio_list {
383 struct bio *head;
384 struct bio *tail;
385};
386
387static inline int bio_list_empty(const struct bio_list *bl)
388{
389 return bl->head == NULL;
390}
391
392static inline void bio_list_init(struct bio_list *bl)
393{
394 bl->head = bl->tail = NULL;
395}
396
397#define bio_list_for_each(bio, bl) \
398 for (bio = (bl)->head; bio; bio = bio->bi_next)
399
400static inline unsigned bio_list_size(const struct bio_list *bl)
401{
402 unsigned sz = 0;
403 struct bio *bio;
404
405 bio_list_for_each(bio, bl)
406 sz++;
407
408 return sz;
409}
410
411static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
412{
413 bio->bi_next = NULL;
414
415 if (bl->tail)
416 bl->tail->bi_next = bio;
417 else
418 bl->head = bio;
419
420 bl->tail = bio;
421}
422
423static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
424{
425 bio->bi_next = bl->head;
426
427 bl->head = bio;
428
429 if (!bl->tail)
430 bl->tail = bio;
431}
432
433static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
434{
435 if (!bl2->head)
436 return;
437
438 if (bl->tail)
439 bl->tail->bi_next = bl2->head;
440 else
441 bl->head = bl2->head;
442
443 bl->tail = bl2->tail;
444}
445
446static inline void bio_list_merge_head(struct bio_list *bl,
447 struct bio_list *bl2)
448{
449 if (!bl2->head)
450 return;
451
452 if (bl->head)
453 bl2->tail->bi_next = bl->head;
454 else
455 bl->tail = bl2->tail;
456
457 bl->head = bl2->head;
458}
459
460static inline struct bio *bio_list_peek(struct bio_list *bl)
461{
462 return bl->head;
463}
464
465static inline struct bio *bio_list_pop(struct bio_list *bl)
466{
467 struct bio *bio = bl->head;
468
469 if (bio) {
470 bl->head = bl->head->bi_next;
471 if (!bl->head)
472 bl->tail = NULL;
473
474 bio->bi_next = NULL;
475 }
476
477 return bio;
478}
479
480static inline struct bio *bio_list_get(struct bio_list *bl)
481{
482 struct bio *bio = bl->head;
483
484 bl->head = bl->tail = NULL;
485
486 return bio;
487}
488
489#if defined(CONFIG_BLK_DEV_INTEGRITY)
490
491#define bip_vec_idx(bip, idx) (&(bip->bip_vec[(idx)]))
492#define bip_vec(bip) bip_vec_idx(bip, 0)
493
494#define __bip_for_each_vec(bvl, bip, i, start_idx) \
495 for (bvl = bip_vec_idx((bip), (start_idx)), i = (start_idx); \
496 i < (bip)->bip_vcnt; \
497 bvl++, i++)
498
499#define bip_for_each_vec(bvl, bip, i) \
500 __bip_for_each_vec(bvl, bip, i, (bip)->bip_idx)
501
502#define bio_for_each_integrity_vec(_bvl, _bio, _iter) \
503 for_each_bio(_bio) \
504 bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
505
506#define bio_integrity(bio) (bio->bi_integrity != NULL)
507
508extern struct bio_integrity_payload *bio_integrity_alloc_bioset(struct bio *, gfp_t, unsigned int, struct bio_set *);
509extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
510extern void bio_integrity_free(struct bio *, struct bio_set *);
511extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
512extern int bio_integrity_enabled(struct bio *bio);
513extern int bio_integrity_set_tag(struct bio *, void *, unsigned int);
514extern int bio_integrity_get_tag(struct bio *, void *, unsigned int);
515extern int bio_integrity_prep(struct bio *);
516extern void bio_integrity_endio(struct bio *, int);
517extern void bio_integrity_advance(struct bio *, unsigned int);
518extern void bio_integrity_trim(struct bio *, unsigned int, unsigned int);
519extern void bio_integrity_split(struct bio *, struct bio_pair *, int);
520extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t, struct bio_set *);
521extern int bioset_integrity_create(struct bio_set *, int);
522extern void bioset_integrity_free(struct bio_set *);
523extern void bio_integrity_init(void);
524
525#else /* CONFIG_BLK_DEV_INTEGRITY */
526
527static inline int bio_integrity(struct bio *bio)
528{
529 return 0;
530}
531
532static inline int bio_integrity_enabled(struct bio *bio)
533{
534 return 0;
535}
536
537static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
538{
539 return 0;
540}
541
542static inline void bioset_integrity_free (struct bio_set *bs)
543{
544 return;
545}
546
547static inline int bio_integrity_prep(struct bio *bio)
548{
549 return 0;
550}
551
552static inline void bio_integrity_free(struct bio *bio, struct bio_set *bs)
553{
554 return;
555}
556
557static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
558 gfp_t gfp_mask, struct bio_set *bs)
559{
560 return 0;
561}
562
563static inline void bio_integrity_split(struct bio *bio, struct bio_pair *bp,
564 int sectors)
565{
566 return;
567}
568
569static inline void bio_integrity_advance(struct bio *bio,
570 unsigned int bytes_done)
571{
572 return;
573}
574
575static inline void bio_integrity_trim(struct bio *bio, unsigned int offset,
576 unsigned int sectors)
577{
578 return;
579}
580
581static inline void bio_integrity_init(void)
582{
583 return;
584}
585
586#endif /* CONFIG_BLK_DEV_INTEGRITY */
587
588#endif /* CONFIG_BLOCK */
589#endif /* __LINUX_BIO_H */