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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_bioset(gfp_t, int, struct bio_set *);
216extern void bio_put(struct bio *);
217
218extern void __bio_clone(struct bio *, struct bio *);
219extern struct bio *bio_clone_bioset(struct bio *, gfp_t, struct bio_set *bs);
220
221extern struct bio_set *fs_bio_set;
222
223static inline struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
224{
225 return bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
226}
227
228static inline struct bio *bio_clone(struct bio *bio, gfp_t gfp_mask)
229{
230 return bio_clone_bioset(bio, gfp_mask, fs_bio_set);
231}
232
233static inline struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs)
234{
235 return bio_alloc_bioset(gfp_mask, nr_iovecs, NULL);
236}
237
238static inline struct bio *bio_clone_kmalloc(struct bio *bio, gfp_t gfp_mask)
239{
240 return bio_clone_bioset(bio, gfp_mask, NULL);
241
242}
243
244extern void bio_endio(struct bio *, int);
245struct request_queue;
246extern int bio_phys_segments(struct request_queue *, struct bio *);
247
248extern void bio_init(struct bio *);
249extern void bio_reset(struct bio *);
250
251extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
252extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
253 unsigned int, unsigned int);
254extern int bio_get_nr_vecs(struct block_device *);
255extern sector_t bio_sector_offset(struct bio *, unsigned short, unsigned int);
256extern struct bio *bio_map_user(struct request_queue *, struct block_device *,
257 unsigned long, unsigned int, int, gfp_t);
258struct sg_iovec;
259struct rq_map_data;
260extern struct bio *bio_map_user_iov(struct request_queue *,
261 struct block_device *,
262 struct sg_iovec *, int, int, gfp_t);
263extern void bio_unmap_user(struct bio *);
264extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
265 gfp_t);
266extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
267 gfp_t, int);
268extern void bio_set_pages_dirty(struct bio *bio);
269extern void bio_check_pages_dirty(struct bio *bio);
270
271#ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
272# error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
273#endif
274#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
275extern void bio_flush_dcache_pages(struct bio *bi);
276#else
277static inline void bio_flush_dcache_pages(struct bio *bi)
278{
279}
280#endif
281
282extern struct bio *bio_copy_user(struct request_queue *, struct rq_map_data *,
283 unsigned long, unsigned int, int, gfp_t);
284extern struct bio *bio_copy_user_iov(struct request_queue *,
285 struct rq_map_data *, struct sg_iovec *,
286 int, int, gfp_t);
287extern int bio_uncopy_user(struct bio *);
288void zero_fill_bio(struct bio *bio);
289extern struct bio_vec *bvec_alloc_bs(gfp_t, int, unsigned long *, struct bio_set *);
290extern void bvec_free_bs(struct bio_set *, struct bio_vec *, unsigned int);
291extern unsigned int bvec_nr_vecs(unsigned short idx);
292
293#ifdef CONFIG_BLK_CGROUP
294int bio_associate_current(struct bio *bio);
295void bio_disassociate_task(struct bio *bio);
296#else /* CONFIG_BLK_CGROUP */
297static inline int bio_associate_current(struct bio *bio) { return -ENOENT; }
298static inline void bio_disassociate_task(struct bio *bio) { }
299#endif /* CONFIG_BLK_CGROUP */
300
301/*
302 * bio_set is used to allow other portions of the IO system to
303 * allocate their own private memory pools for bio and iovec structures.
304 * These memory pools in turn all allocate from the bio_slab
305 * and the bvec_slabs[].
306 */
307#define BIO_POOL_SIZE 2
308#define BIOVEC_NR_POOLS 6
309#define BIOVEC_MAX_IDX (BIOVEC_NR_POOLS - 1)
310
311struct bio_set {
312 struct kmem_cache *bio_slab;
313 unsigned int front_pad;
314
315 mempool_t *bio_pool;
316#if defined(CONFIG_BLK_DEV_INTEGRITY)
317 mempool_t *bio_integrity_pool;
318#endif
319 mempool_t *bvec_pool;
320};
321
322struct biovec_slab {
323 int nr_vecs;
324 char *name;
325 struct kmem_cache *slab;
326};
327
328/*
329 * a small number of entries is fine, not going to be performance critical.
330 * basically we just need to survive
331 */
332#define BIO_SPLIT_ENTRIES 2
333
334#ifdef CONFIG_HIGHMEM
335/*
336 * remember never ever reenable interrupts between a bvec_kmap_irq and
337 * bvec_kunmap_irq!
338 */
339static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
340{
341 unsigned long addr;
342
343 /*
344 * might not be a highmem page, but the preempt/irq count
345 * balancing is a lot nicer this way
346 */
347 local_irq_save(*flags);
348 addr = (unsigned long) kmap_atomic(bvec->bv_page);
349
350 BUG_ON(addr & ~PAGE_MASK);
351
352 return (char *) addr + bvec->bv_offset;
353}
354
355static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
356{
357 unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
358
359 kunmap_atomic((void *) ptr);
360 local_irq_restore(*flags);
361}
362
363#else
364static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
365{
366 return page_address(bvec->bv_page) + bvec->bv_offset;
367}
368
369static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
370{
371 *flags = 0;
372}
373#endif
374
375static inline char *__bio_kmap_irq(struct bio *bio, unsigned short idx,
376 unsigned long *flags)
377{
378 return bvec_kmap_irq(bio_iovec_idx(bio, idx), flags);
379}
380#define __bio_kunmap_irq(buf, flags) bvec_kunmap_irq(buf, flags)
381
382#define bio_kmap_irq(bio, flags) \
383 __bio_kmap_irq((bio), (bio)->bi_idx, (flags))
384#define bio_kunmap_irq(buf,flags) __bio_kunmap_irq(buf, flags)
385
386/*
387 * Check whether this bio carries any data or not. A NULL bio is allowed.
388 */
389static inline bool bio_has_data(struct bio *bio)
390{
391 if (bio && bio->bi_vcnt)
392 return true;
393
394 return false;
395}
396
397static inline bool bio_is_rw(struct bio *bio)
398{
399 if (!bio_has_data(bio))
400 return false;
401
402 if (bio->bi_rw & REQ_WRITE_SAME)
403 return false;
404
405 return true;
406}
407
408static inline bool bio_mergeable(struct bio *bio)
409{
410 if (bio->bi_rw & REQ_NOMERGE_FLAGS)
411 return false;
412
413 return true;
414}
415
416/*
417 * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
418 *
419 * A bio_list anchors a singly-linked list of bios chained through the bi_next
420 * member of the bio. The bio_list also caches the last list member to allow
421 * fast access to the tail.
422 */
423struct bio_list {
424 struct bio *head;
425 struct bio *tail;
426};
427
428static inline int bio_list_empty(const struct bio_list *bl)
429{
430 return bl->head == NULL;
431}
432
433static inline void bio_list_init(struct bio_list *bl)
434{
435 bl->head = bl->tail = NULL;
436}
437
438#define bio_list_for_each(bio, bl) \
439 for (bio = (bl)->head; bio; bio = bio->bi_next)
440
441static inline unsigned bio_list_size(const struct bio_list *bl)
442{
443 unsigned sz = 0;
444 struct bio *bio;
445
446 bio_list_for_each(bio, bl)
447 sz++;
448
449 return sz;
450}
451
452static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
453{
454 bio->bi_next = NULL;
455
456 if (bl->tail)
457 bl->tail->bi_next = bio;
458 else
459 bl->head = bio;
460
461 bl->tail = bio;
462}
463
464static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
465{
466 bio->bi_next = bl->head;
467
468 bl->head = bio;
469
470 if (!bl->tail)
471 bl->tail = bio;
472}
473
474static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
475{
476 if (!bl2->head)
477 return;
478
479 if (bl->tail)
480 bl->tail->bi_next = bl2->head;
481 else
482 bl->head = bl2->head;
483
484 bl->tail = bl2->tail;
485}
486
487static inline void bio_list_merge_head(struct bio_list *bl,
488 struct bio_list *bl2)
489{
490 if (!bl2->head)
491 return;
492
493 if (bl->head)
494 bl2->tail->bi_next = bl->head;
495 else
496 bl->tail = bl2->tail;
497
498 bl->head = bl2->head;
499}
500
501static inline struct bio *bio_list_peek(struct bio_list *bl)
502{
503 return bl->head;
504}
505
506static inline struct bio *bio_list_pop(struct bio_list *bl)
507{
508 struct bio *bio = bl->head;
509
510 if (bio) {
511 bl->head = bl->head->bi_next;
512 if (!bl->head)
513 bl->tail = NULL;
514
515 bio->bi_next = NULL;
516 }
517
518 return bio;
519}
520
521static inline struct bio *bio_list_get(struct bio_list *bl)
522{
523 struct bio *bio = bl->head;
524
525 bl->head = bl->tail = NULL;
526
527 return bio;
528}
529
530#if defined(CONFIG_BLK_DEV_INTEGRITY)
531
532#define bip_vec_idx(bip, idx) (&(bip->bip_vec[(idx)]))
533#define bip_vec(bip) bip_vec_idx(bip, 0)
534
535#define __bip_for_each_vec(bvl, bip, i, start_idx) \
536 for (bvl = bip_vec_idx((bip), (start_idx)), i = (start_idx); \
537 i < (bip)->bip_vcnt; \
538 bvl++, i++)
539
540#define bip_for_each_vec(bvl, bip, i) \
541 __bip_for_each_vec(bvl, bip, i, (bip)->bip_idx)
542
543#define bio_for_each_integrity_vec(_bvl, _bio, _iter) \
544 for_each_bio(_bio) \
545 bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
546
547#define bio_integrity(bio) (bio->bi_integrity != NULL)
548
549extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
550extern void bio_integrity_free(struct bio *);
551extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
552extern int bio_integrity_enabled(struct bio *bio);
553extern int bio_integrity_set_tag(struct bio *, void *, unsigned int);
554extern int bio_integrity_get_tag(struct bio *, void *, unsigned int);
555extern int bio_integrity_prep(struct bio *);
556extern void bio_integrity_endio(struct bio *, int);
557extern void bio_integrity_advance(struct bio *, unsigned int);
558extern void bio_integrity_trim(struct bio *, unsigned int, unsigned int);
559extern void bio_integrity_split(struct bio *, struct bio_pair *, int);
560extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t);
561extern int bioset_integrity_create(struct bio_set *, int);
562extern void bioset_integrity_free(struct bio_set *);
563extern void bio_integrity_init(void);
564
565#else /* CONFIG_BLK_DEV_INTEGRITY */
566
567static inline int bio_integrity(struct bio *bio)
568{
569 return 0;
570}
571
572static inline int bio_integrity_enabled(struct bio *bio)
573{
574 return 0;
575}
576
577static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
578{
579 return 0;
580}
581
582static inline void bioset_integrity_free (struct bio_set *bs)
583{
584 return;
585}
586
587static inline int bio_integrity_prep(struct bio *bio)
588{
589 return 0;
590}
591
592static inline void bio_integrity_free(struct bio *bio)
593{
594 return;
595}
596
597static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
598 gfp_t gfp_mask)
599{
600 return 0;
601}
602
603static inline void bio_integrity_split(struct bio *bio, struct bio_pair *bp,
604 int sectors)
605{
606 return;
607}
608
609static inline void bio_integrity_advance(struct bio *bio,
610 unsigned int bytes_done)
611{
612 return;
613}
614
615static inline void bio_integrity_trim(struct bio *bio, unsigned int offset,
616 unsigned int sectors)
617{
618 return;
619}
620
621static inline void bio_integrity_init(void)
622{
623 return;
624}
625
626#endif /* CONFIG_BLK_DEV_INTEGRITY */
627
628#endif /* CONFIG_BLOCK */
629#endif /* __LINUX_BIO_H */