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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/* Platforms may set this to teach the BIO layer about IOMMU hardware. */
30#include <asm/io.h>
31
32#if defined(BIO_VMERGE_MAX_SIZE) && defined(BIO_VMERGE_BOUNDARY)
33#define BIOVEC_VIRT_START_SIZE(x) (bvec_to_phys(x) & (BIO_VMERGE_BOUNDARY - 1))
34#define BIOVEC_VIRT_OVERSIZE(x) ((x) > BIO_VMERGE_MAX_SIZE)
35#else
36#define BIOVEC_VIRT_START_SIZE(x) 0
37#define BIOVEC_VIRT_OVERSIZE(x) 0
38#endif
39
40#ifndef BIO_VMERGE_BOUNDARY
41#define BIO_VMERGE_BOUNDARY 0
42#endif
43
44#define BIO_DEBUG
45
46#ifdef BIO_DEBUG
47#define BIO_BUG_ON BUG_ON
48#else
49#define BIO_BUG_ON
50#endif
51
52#define BIO_MAX_PAGES 256
53#define BIO_MAX_SIZE (BIO_MAX_PAGES << PAGE_CACHE_SHIFT)
54#define BIO_MAX_SECTORS (BIO_MAX_SIZE >> 9)
55
56/*
57 * was unsigned short, but we might as well be ready for > 64kB I/O pages
58 */
59struct bio_vec {
60 struct page *bv_page;
61 unsigned int bv_len;
62 unsigned int bv_offset;
63};
64
65struct bio_set;
66struct bio;
67struct bio_integrity_payload;
68typedef void (bio_end_io_t) (struct bio *, int);
69typedef void (bio_destructor_t) (struct bio *);
70
71/*
72 * main unit of I/O for the block layer and lower layers (ie drivers and
73 * stacking drivers)
74 */
75struct bio {
76 sector_t bi_sector; /* device address in 512 byte
77 sectors */
78 struct bio *bi_next; /* request queue link */
79 struct block_device *bi_bdev;
80 unsigned long bi_flags; /* status, command, etc */
81 unsigned long bi_rw; /* bottom bits READ/WRITE,
82 * top bits priority
83 */
84
85 unsigned short bi_vcnt; /* how many bio_vec's */
86 unsigned short bi_idx; /* current index into bvl_vec */
87
88 /* Number of segments in this BIO after
89 * physical address coalescing is performed.
90 */
91 unsigned short bi_phys_segments;
92
93 /* Number of segments after physical and DMA remapping
94 * hardware coalescing is performed.
95 */
96 unsigned short bi_hw_segments;
97
98 unsigned int bi_size; /* residual I/O count */
99
100 /*
101 * To keep track of the max hw size, we account for the
102 * sizes of the first and last virtually mergeable segments
103 * in this bio
104 */
105 unsigned int bi_hw_front_size;
106 unsigned int bi_hw_back_size;
107
108 unsigned int bi_max_vecs; /* max bvl_vecs we can hold */
109
110 struct bio_vec *bi_io_vec; /* the actual vec list */
111
112 bio_end_io_t *bi_end_io;
113 atomic_t bi_cnt; /* pin count */
114
115 void *bi_private;
116#if defined(CONFIG_BLK_DEV_INTEGRITY)
117 struct bio_integrity_payload *bi_integrity; /* data integrity */
118#endif
119
120 bio_destructor_t *bi_destructor; /* destructor */
121};
122
123/*
124 * bio flags
125 */
126#define BIO_UPTODATE 0 /* ok after I/O completion */
127#define BIO_RW_BLOCK 1 /* RW_AHEAD set, and read/write would block */
128#define BIO_EOF 2 /* out-out-bounds error */
129#define BIO_SEG_VALID 3 /* nr_hw_seg valid */
130#define BIO_CLONED 4 /* doesn't own data */
131#define BIO_BOUNCED 5 /* bio is a bounce bio */
132#define BIO_USER_MAPPED 6 /* contains user pages */
133#define BIO_EOPNOTSUPP 7 /* not supported */
134#define bio_flagged(bio, flag) ((bio)->bi_flags & (1 << (flag)))
135
136/*
137 * top 4 bits of bio flags indicate the pool this bio came from
138 */
139#define BIO_POOL_BITS (4)
140#define BIO_POOL_OFFSET (BITS_PER_LONG - BIO_POOL_BITS)
141#define BIO_POOL_MASK (1UL << BIO_POOL_OFFSET)
142#define BIO_POOL_IDX(bio) ((bio)->bi_flags >> BIO_POOL_OFFSET)
143
144/*
145 * bio bi_rw flags
146 *
147 * bit 0 -- read (not set) or write (set)
148 * bit 1 -- rw-ahead when set
149 * bit 2 -- barrier
150 * bit 3 -- fail fast, don't want low level driver retries
151 * bit 4 -- synchronous I/O hint: the block layer will unplug immediately
152 */
153#define BIO_RW 0
154#define BIO_RW_AHEAD 1
155#define BIO_RW_BARRIER 2
156#define BIO_RW_FAILFAST 3
157#define BIO_RW_SYNC 4
158#define BIO_RW_META 5
159
160/*
161 * upper 16 bits of bi_rw define the io priority of this bio
162 */
163#define BIO_PRIO_SHIFT (8 * sizeof(unsigned long) - IOPRIO_BITS)
164#define bio_prio(bio) ((bio)->bi_rw >> BIO_PRIO_SHIFT)
165#define bio_prio_valid(bio) ioprio_valid(bio_prio(bio))
166
167#define bio_set_prio(bio, prio) do { \
168 WARN_ON(prio >= (1 << IOPRIO_BITS)); \
169 (bio)->bi_rw &= ((1UL << BIO_PRIO_SHIFT) - 1); \
170 (bio)->bi_rw |= ((unsigned long) (prio) << BIO_PRIO_SHIFT); \
171} while (0)
172
173/*
174 * various member access, note that bio_data should of course not be used
175 * on highmem page vectors
176 */
177#define bio_iovec_idx(bio, idx) (&((bio)->bi_io_vec[(idx)]))
178#define bio_iovec(bio) bio_iovec_idx((bio), (bio)->bi_idx)
179#define bio_page(bio) bio_iovec((bio))->bv_page
180#define bio_offset(bio) bio_iovec((bio))->bv_offset
181#define bio_segments(bio) ((bio)->bi_vcnt - (bio)->bi_idx)
182#define bio_sectors(bio) ((bio)->bi_size >> 9)
183#define bio_barrier(bio) ((bio)->bi_rw & (1 << BIO_RW_BARRIER))
184#define bio_sync(bio) ((bio)->bi_rw & (1 << BIO_RW_SYNC))
185#define bio_failfast(bio) ((bio)->bi_rw & (1 << BIO_RW_FAILFAST))
186#define bio_rw_ahead(bio) ((bio)->bi_rw & (1 << BIO_RW_AHEAD))
187#define bio_rw_meta(bio) ((bio)->bi_rw & (1 << BIO_RW_META))
188#define bio_empty_barrier(bio) (bio_barrier(bio) && !(bio)->bi_size)
189
190static inline unsigned int bio_cur_sectors(struct bio *bio)
191{
192 if (bio->bi_vcnt)
193 return bio_iovec(bio)->bv_len >> 9;
194
195 return 0;
196}
197
198static inline void *bio_data(struct bio *bio)
199{
200 if (bio->bi_vcnt)
201 return page_address(bio_page(bio)) + bio_offset(bio);
202
203 return NULL;
204}
205
206/*
207 * will die
208 */
209#define bio_to_phys(bio) (page_to_phys(bio_page((bio))) + (unsigned long) bio_offset((bio)))
210#define bvec_to_phys(bv) (page_to_phys((bv)->bv_page) + (unsigned long) (bv)->bv_offset)
211
212/*
213 * queues that have highmem support enabled may still need to revert to
214 * PIO transfers occasionally and thus map high pages temporarily. For
215 * permanent PIO fall back, user is probably better off disabling highmem
216 * I/O completely on that queue (see ide-dma for example)
217 */
218#define __bio_kmap_atomic(bio, idx, kmtype) \
219 (kmap_atomic(bio_iovec_idx((bio), (idx))->bv_page, kmtype) + \
220 bio_iovec_idx((bio), (idx))->bv_offset)
221
222#define __bio_kunmap_atomic(addr, kmtype) kunmap_atomic(addr, kmtype)
223
224/*
225 * merge helpers etc
226 */
227
228#define __BVEC_END(bio) bio_iovec_idx((bio), (bio)->bi_vcnt - 1)
229#define __BVEC_START(bio) bio_iovec_idx((bio), (bio)->bi_idx)
230
231/*
232 * allow arch override, for eg virtualized architectures (put in asm/io.h)
233 */
234#ifndef BIOVEC_PHYS_MERGEABLE
235#define BIOVEC_PHYS_MERGEABLE(vec1, vec2) \
236 ((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2)))
237#endif
238
239#define BIOVEC_VIRT_MERGEABLE(vec1, vec2) \
240 ((((bvec_to_phys((vec1)) + (vec1)->bv_len) | bvec_to_phys((vec2))) & (BIO_VMERGE_BOUNDARY - 1)) == 0)
241#define __BIO_SEG_BOUNDARY(addr1, addr2, mask) \
242 (((addr1) | (mask)) == (((addr2) - 1) | (mask)))
243#define BIOVEC_SEG_BOUNDARY(q, b1, b2) \
244 __BIO_SEG_BOUNDARY(bvec_to_phys((b1)), bvec_to_phys((b2)) + (b2)->bv_len, (q)->seg_boundary_mask)
245#define BIO_SEG_BOUNDARY(q, b1, b2) \
246 BIOVEC_SEG_BOUNDARY((q), __BVEC_END((b1)), __BVEC_START((b2)))
247
248#define bio_io_error(bio) bio_endio((bio), -EIO)
249
250/*
251 * drivers should not use the __ version unless they _really_ want to
252 * run through the entire bio and not just pending pieces
253 */
254#define __bio_for_each_segment(bvl, bio, i, start_idx) \
255 for (bvl = bio_iovec_idx((bio), (start_idx)), i = (start_idx); \
256 i < (bio)->bi_vcnt; \
257 bvl++, i++)
258
259#define bio_for_each_segment(bvl, bio, i) \
260 __bio_for_each_segment(bvl, bio, i, (bio)->bi_idx)
261
262/*
263 * get a reference to a bio, so it won't disappear. the intended use is
264 * something like:
265 *
266 * bio_get(bio);
267 * submit_bio(rw, bio);
268 * if (bio->bi_flags ...)
269 * do_something
270 * bio_put(bio);
271 *
272 * without the bio_get(), it could potentially complete I/O before submit_bio
273 * returns. and then bio would be freed memory when if (bio->bi_flags ...)
274 * runs
275 */
276#define bio_get(bio) atomic_inc(&(bio)->bi_cnt)
277
278#if defined(CONFIG_BLK_DEV_INTEGRITY)
279/*
280 * bio integrity payload
281 */
282struct bio_integrity_payload {
283 struct bio *bip_bio; /* parent bio */
284 struct bio_vec *bip_vec; /* integrity data vector */
285
286 sector_t bip_sector; /* virtual start sector */
287
288 void *bip_buf; /* generated integrity data */
289 bio_end_io_t *bip_end_io; /* saved I/O completion fn */
290
291 int bip_error; /* saved I/O error */
292 unsigned int bip_size;
293
294 unsigned short bip_pool; /* pool the ivec came from */
295 unsigned short bip_vcnt; /* # of integrity bio_vecs */
296 unsigned short bip_idx; /* current bip_vec index */
297
298 struct work_struct bip_work; /* I/O completion */
299};
300#endif /* CONFIG_BLK_DEV_INTEGRITY */
301
302/*
303 * A bio_pair is used when we need to split a bio.
304 * This can only happen for a bio that refers to just one
305 * page of data, and in the unusual situation when the
306 * page crosses a chunk/device boundary
307 *
308 * The address of the master bio is stored in bio1.bi_private
309 * The address of the pool the pair was allocated from is stored
310 * in bio2.bi_private
311 */
312struct bio_pair {
313 struct bio bio1, bio2;
314 struct bio_vec bv1, bv2;
315#if defined(CONFIG_BLK_DEV_INTEGRITY)
316 struct bio_integrity_payload bip1, bip2;
317 struct bio_vec iv1, iv2;
318#endif
319 atomic_t cnt;
320 int error;
321};
322extern struct bio_pair *bio_split(struct bio *bi, mempool_t *pool,
323 int first_sectors);
324extern mempool_t *bio_split_pool;
325extern void bio_pair_release(struct bio_pair *dbio);
326
327extern struct bio_set *bioset_create(int, int);
328extern void bioset_free(struct bio_set *);
329
330extern struct bio *bio_alloc(gfp_t, int);
331extern struct bio *bio_alloc_bioset(gfp_t, int, struct bio_set *);
332extern void bio_put(struct bio *);
333extern void bio_free(struct bio *, struct bio_set *);
334
335extern void bio_endio(struct bio *, int);
336struct request_queue;
337extern int bio_phys_segments(struct request_queue *, struct bio *);
338extern int bio_hw_segments(struct request_queue *, struct bio *);
339
340extern void __bio_clone(struct bio *, struct bio *);
341extern struct bio *bio_clone(struct bio *, gfp_t);
342
343extern void bio_init(struct bio *);
344
345extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
346extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
347 unsigned int, unsigned int);
348extern int bio_get_nr_vecs(struct block_device *);
349extern struct bio *bio_map_user(struct request_queue *, struct block_device *,
350 unsigned long, unsigned int, int);
351struct sg_iovec;
352extern struct bio *bio_map_user_iov(struct request_queue *,
353 struct block_device *,
354 struct sg_iovec *, int, int);
355extern void bio_unmap_user(struct bio *);
356extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
357 gfp_t);
358extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
359 gfp_t, int);
360extern void bio_set_pages_dirty(struct bio *bio);
361extern void bio_check_pages_dirty(struct bio *bio);
362extern struct bio *bio_copy_user(struct request_queue *, unsigned long, unsigned int, int);
363extern struct bio *bio_copy_user_iov(struct request_queue *, struct sg_iovec *,
364 int, int);
365extern int bio_uncopy_user(struct bio *);
366void zero_fill_bio(struct bio *bio);
367extern struct bio_vec *bvec_alloc_bs(gfp_t, int, unsigned long *, struct bio_set *);
368extern unsigned int bvec_nr_vecs(unsigned short idx);
369
370/*
371 * bio_set is used to allow other portions of the IO system to
372 * allocate their own private memory pools for bio and iovec structures.
373 * These memory pools in turn all allocate from the bio_slab
374 * and the bvec_slabs[].
375 */
376#define BIO_POOL_SIZE 2
377#define BIOVEC_NR_POOLS 6
378
379struct bio_set {
380 mempool_t *bio_pool;
381#if defined(CONFIG_BLK_DEV_INTEGRITY)
382 mempool_t *bio_integrity_pool;
383#endif
384 mempool_t *bvec_pools[BIOVEC_NR_POOLS];
385};
386
387struct biovec_slab {
388 int nr_vecs;
389 char *name;
390 struct kmem_cache *slab;
391};
392
393extern struct bio_set *fs_bio_set;
394
395/*
396 * a small number of entries is fine, not going to be performance critical.
397 * basically we just need to survive
398 */
399#define BIO_SPLIT_ENTRIES 2
400
401#ifdef CONFIG_HIGHMEM
402/*
403 * remember to add offset! and never ever reenable interrupts between a
404 * bvec_kmap_irq and bvec_kunmap_irq!!
405 *
406 * This function MUST be inlined - it plays with the CPU interrupt flags.
407 */
408static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
409{
410 unsigned long addr;
411
412 /*
413 * might not be a highmem page, but the preempt/irq count
414 * balancing is a lot nicer this way
415 */
416 local_irq_save(*flags);
417 addr = (unsigned long) kmap_atomic(bvec->bv_page, KM_BIO_SRC_IRQ);
418
419 BUG_ON(addr & ~PAGE_MASK);
420
421 return (char *) addr + bvec->bv_offset;
422}
423
424static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
425{
426 unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
427
428 kunmap_atomic((void *) ptr, KM_BIO_SRC_IRQ);
429 local_irq_restore(*flags);
430}
431
432#else
433#define bvec_kmap_irq(bvec, flags) (page_address((bvec)->bv_page) + (bvec)->bv_offset)
434#define bvec_kunmap_irq(buf, flags) do { *(flags) = 0; } while (0)
435#endif
436
437static inline char *__bio_kmap_irq(struct bio *bio, unsigned short idx,
438 unsigned long *flags)
439{
440 return bvec_kmap_irq(bio_iovec_idx(bio, idx), flags);
441}
442#define __bio_kunmap_irq(buf, flags) bvec_kunmap_irq(buf, flags)
443
444#define bio_kmap_irq(bio, flags) \
445 __bio_kmap_irq((bio), (bio)->bi_idx, (flags))
446#define bio_kunmap_irq(buf,flags) __bio_kunmap_irq(buf, flags)
447
448#if defined(CONFIG_BLK_DEV_INTEGRITY)
449
450#define bip_vec_idx(bip, idx) (&(bip->bip_vec[(idx)]))
451#define bip_vec(bip) bip_vec_idx(bip, 0)
452
453#define __bip_for_each_vec(bvl, bip, i, start_idx) \
454 for (bvl = bip_vec_idx((bip), (start_idx)), i = (start_idx); \
455 i < (bip)->bip_vcnt; \
456 bvl++, i++)
457
458#define bip_for_each_vec(bvl, bip, i) \
459 __bip_for_each_vec(bvl, bip, i, (bip)->bip_idx)
460
461static inline int bio_integrity(struct bio *bio)
462{
463#if defined(CONFIG_BLK_DEV_INTEGRITY)
464 return bio->bi_integrity != NULL;
465#else
466 return 0;
467#endif
468}
469
470extern struct bio_integrity_payload *bio_integrity_alloc_bioset(struct bio *, gfp_t, unsigned int, struct bio_set *);
471extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
472extern void bio_integrity_free(struct bio *, struct bio_set *);
473extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
474extern int bio_integrity_enabled(struct bio *bio);
475extern int bio_integrity_set_tag(struct bio *, void *, unsigned int);
476extern int bio_integrity_get_tag(struct bio *, void *, unsigned int);
477extern int bio_integrity_prep(struct bio *);
478extern void bio_integrity_endio(struct bio *, int);
479extern void bio_integrity_advance(struct bio *, unsigned int);
480extern void bio_integrity_trim(struct bio *, unsigned int, unsigned int);
481extern void bio_integrity_split(struct bio *, struct bio_pair *, int);
482extern int bio_integrity_clone(struct bio *, struct bio *, struct bio_set *);
483extern int bioset_integrity_create(struct bio_set *, int);
484extern void bioset_integrity_free(struct bio_set *);
485extern void bio_integrity_init_slab(void);
486
487#else /* CONFIG_BLK_DEV_INTEGRITY */
488
489#define bio_integrity(a) (0)
490#define bioset_integrity_create(a, b) (0)
491#define bio_integrity_prep(a) (0)
492#define bio_integrity_enabled(a) (0)
493#define bio_integrity_clone(a, b, c) (0)
494#define bioset_integrity_free(a) do { } while (0)
495#define bio_integrity_free(a, b) do { } while (0)
496#define bio_integrity_endio(a, b) do { } while (0)
497#define bio_integrity_advance(a, b) do { } while (0)
498#define bio_integrity_trim(a, b, c) do { } while (0)
499#define bio_integrity_split(a, b, c) do { } while (0)
500#define bio_integrity_set_tag(a, b, c) do { } while (0)
501#define bio_integrity_get_tag(a, b, c) do { } while (0)
502#define bio_integrity_init_slab(a) do { } while (0)
503
504#endif /* CONFIG_BLK_DEV_INTEGRITY */
505
506#endif /* CONFIG_BLOCK */
507#endif /* __LINUX_BIO_H */