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