diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /include/linux/bio.h |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'include/linux/bio.h')
-rw-r--r-- | include/linux/bio.h | 339 |
1 files changed, 339 insertions, 0 deletions
diff --git a/include/linux/bio.h b/include/linux/bio.h new file mode 100644 index 000000000000..038022763f09 --- /dev/null +++ b/include/linux/bio.h | |||
@@ -0,0 +1,339 @@ | |||
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 | |||
26 | /* Platforms may set this to teach the BIO layer about IOMMU hardware. */ | ||
27 | #include <asm/io.h> | ||
28 | |||
29 | #if defined(BIO_VMERGE_MAX_SIZE) && defined(BIO_VMERGE_BOUNDARY) | ||
30 | #define BIOVEC_VIRT_START_SIZE(x) (bvec_to_phys(x) & (BIO_VMERGE_BOUNDARY - 1)) | ||
31 | #define BIOVEC_VIRT_OVERSIZE(x) ((x) > BIO_VMERGE_MAX_SIZE) | ||
32 | #else | ||
33 | #define BIOVEC_VIRT_START_SIZE(x) 0 | ||
34 | #define BIOVEC_VIRT_OVERSIZE(x) 0 | ||
35 | #endif | ||
36 | |||
37 | #ifndef BIO_VMERGE_BOUNDARY | ||
38 | #define BIO_VMERGE_BOUNDARY 0 | ||
39 | #endif | ||
40 | |||
41 | #define BIO_DEBUG | ||
42 | |||
43 | #ifdef BIO_DEBUG | ||
44 | #define BIO_BUG_ON BUG_ON | ||
45 | #else | ||
46 | #define BIO_BUG_ON | ||
47 | #endif | ||
48 | |||
49 | #define BIO_MAX_PAGES (256) | ||
50 | #define BIO_MAX_SIZE (BIO_MAX_PAGES << PAGE_CACHE_SHIFT) | ||
51 | #define BIO_MAX_SECTORS (BIO_MAX_SIZE >> 9) | ||
52 | |||
53 | /* | ||
54 | * was unsigned short, but we might as well be ready for > 64kB I/O pages | ||
55 | */ | ||
56 | struct bio_vec { | ||
57 | struct page *bv_page; | ||
58 | unsigned int bv_len; | ||
59 | unsigned int bv_offset; | ||
60 | }; | ||
61 | |||
62 | struct bio_set; | ||
63 | struct bio; | ||
64 | typedef int (bio_end_io_t) (struct bio *, unsigned int, int); | ||
65 | typedef void (bio_destructor_t) (struct bio *); | ||
66 | |||
67 | /* | ||
68 | * main unit of I/O for the block layer and lower layers (ie drivers and | ||
69 | * stacking drivers) | ||
70 | */ | ||
71 | struct bio { | ||
72 | sector_t bi_sector; | ||
73 | struct bio *bi_next; /* request queue link */ | ||
74 | struct block_device *bi_bdev; | ||
75 | unsigned long bi_flags; /* status, command, etc */ | ||
76 | unsigned long bi_rw; /* bottom bits READ/WRITE, | ||
77 | * top bits priority | ||
78 | */ | ||
79 | |||
80 | unsigned short bi_vcnt; /* how many bio_vec's */ | ||
81 | unsigned short bi_idx; /* current index into bvl_vec */ | ||
82 | |||
83 | /* Number of segments in this BIO after | ||
84 | * physical address coalescing is performed. | ||
85 | */ | ||
86 | unsigned short bi_phys_segments; | ||
87 | |||
88 | /* Number of segments after physical and DMA remapping | ||
89 | * hardware coalescing is performed. | ||
90 | */ | ||
91 | unsigned short bi_hw_segments; | ||
92 | |||
93 | unsigned int bi_size; /* residual I/O count */ | ||
94 | |||
95 | /* | ||
96 | * To keep track of the max hw size, we account for the | ||
97 | * sizes of the first and last virtually mergeable segments | ||
98 | * in this bio | ||
99 | */ | ||
100 | unsigned int bi_hw_front_size; | ||
101 | unsigned int bi_hw_back_size; | ||
102 | |||
103 | unsigned int bi_max_vecs; /* max bvl_vecs we can hold */ | ||
104 | |||
105 | struct bio_vec *bi_io_vec; /* the actual vec list */ | ||
106 | |||
107 | bio_end_io_t *bi_end_io; | ||
108 | atomic_t bi_cnt; /* pin count */ | ||
109 | |||
110 | void *bi_private; | ||
111 | |||
112 | bio_destructor_t *bi_destructor; /* destructor */ | ||
113 | struct bio_set *bi_set; /* memory pools set */ | ||
114 | }; | ||
115 | |||
116 | /* | ||
117 | * bio flags | ||
118 | */ | ||
119 | #define BIO_UPTODATE 0 /* ok after I/O completion */ | ||
120 | #define BIO_RW_BLOCK 1 /* RW_AHEAD set, and read/write would block */ | ||
121 | #define BIO_EOF 2 /* out-out-bounds error */ | ||
122 | #define BIO_SEG_VALID 3 /* nr_hw_seg valid */ | ||
123 | #define BIO_CLONED 4 /* doesn't own data */ | ||
124 | #define BIO_BOUNCED 5 /* bio is a bounce bio */ | ||
125 | #define BIO_USER_MAPPED 6 /* contains user pages */ | ||
126 | #define BIO_EOPNOTSUPP 7 /* not supported */ | ||
127 | #define bio_flagged(bio, flag) ((bio)->bi_flags & (1 << (flag))) | ||
128 | |||
129 | /* | ||
130 | * top 4 bits of bio flags indicate the pool this bio came from | ||
131 | */ | ||
132 | #define BIO_POOL_BITS (4) | ||
133 | #define BIO_POOL_OFFSET (BITS_PER_LONG - BIO_POOL_BITS) | ||
134 | #define BIO_POOL_MASK (1UL << BIO_POOL_OFFSET) | ||
135 | #define BIO_POOL_IDX(bio) ((bio)->bi_flags >> BIO_POOL_OFFSET) | ||
136 | |||
137 | /* | ||
138 | * bio bi_rw flags | ||
139 | * | ||
140 | * bit 0 -- read (not set) or write (set) | ||
141 | * bit 1 -- rw-ahead when set | ||
142 | * bit 2 -- barrier | ||
143 | * bit 3 -- fail fast, don't want low level driver retries | ||
144 | * bit 4 -- synchronous I/O hint: the block layer will unplug immediately | ||
145 | */ | ||
146 | #define BIO_RW 0 | ||
147 | #define BIO_RW_AHEAD 1 | ||
148 | #define BIO_RW_BARRIER 2 | ||
149 | #define BIO_RW_FAILFAST 3 | ||
150 | #define BIO_RW_SYNC 4 | ||
151 | |||
152 | /* | ||
153 | * various member access, note that bio_data should of course not be used | ||
154 | * on highmem page vectors | ||
155 | */ | ||
156 | #define bio_iovec_idx(bio, idx) (&((bio)->bi_io_vec[(idx)])) | ||
157 | #define bio_iovec(bio) bio_iovec_idx((bio), (bio)->bi_idx) | ||
158 | #define bio_page(bio) bio_iovec((bio))->bv_page | ||
159 | #define bio_offset(bio) bio_iovec((bio))->bv_offset | ||
160 | #define bio_segments(bio) ((bio)->bi_vcnt - (bio)->bi_idx) | ||
161 | #define bio_sectors(bio) ((bio)->bi_size >> 9) | ||
162 | #define bio_cur_sectors(bio) (bio_iovec(bio)->bv_len >> 9) | ||
163 | #define bio_data(bio) (page_address(bio_page((bio))) + bio_offset((bio))) | ||
164 | #define bio_barrier(bio) ((bio)->bi_rw & (1 << BIO_RW_BARRIER)) | ||
165 | #define bio_sync(bio) ((bio)->bi_rw & (1 << BIO_RW_SYNC)) | ||
166 | #define bio_failfast(bio) ((bio)->bi_rw & (1 << BIO_RW_FAILFAST)) | ||
167 | #define bio_rw_ahead(bio) ((bio)->bi_rw & (1 << BIO_RW_AHEAD)) | ||
168 | |||
169 | /* | ||
170 | * will die | ||
171 | */ | ||
172 | #define bio_to_phys(bio) (page_to_phys(bio_page((bio))) + (unsigned long) bio_offset((bio))) | ||
173 | #define bvec_to_phys(bv) (page_to_phys((bv)->bv_page) + (unsigned long) (bv)->bv_offset) | ||
174 | |||
175 | /* | ||
176 | * queues that have highmem support enabled may still need to revert to | ||
177 | * PIO transfers occasionally and thus map high pages temporarily. For | ||
178 | * permanent PIO fall back, user is probably better off disabling highmem | ||
179 | * I/O completely on that queue (see ide-dma for example) | ||
180 | */ | ||
181 | #define __bio_kmap_atomic(bio, idx, kmtype) \ | ||
182 | (kmap_atomic(bio_iovec_idx((bio), (idx))->bv_page, kmtype) + \ | ||
183 | bio_iovec_idx((bio), (idx))->bv_offset) | ||
184 | |||
185 | #define __bio_kunmap_atomic(addr, kmtype) kunmap_atomic(addr, kmtype) | ||
186 | |||
187 | /* | ||
188 | * merge helpers etc | ||
189 | */ | ||
190 | |||
191 | #define __BVEC_END(bio) bio_iovec_idx((bio), (bio)->bi_vcnt - 1) | ||
192 | #define __BVEC_START(bio) bio_iovec_idx((bio), (bio)->bi_idx) | ||
193 | |||
194 | /* | ||
195 | * allow arch override, for eg virtualized architectures (put in asm/io.h) | ||
196 | */ | ||
197 | #ifndef BIOVEC_PHYS_MERGEABLE | ||
198 | #define BIOVEC_PHYS_MERGEABLE(vec1, vec2) \ | ||
199 | ((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2))) | ||
200 | #endif | ||
201 | |||
202 | #define BIOVEC_VIRT_MERGEABLE(vec1, vec2) \ | ||
203 | ((((bvec_to_phys((vec1)) + (vec1)->bv_len) | bvec_to_phys((vec2))) & (BIO_VMERGE_BOUNDARY - 1)) == 0) | ||
204 | #define __BIO_SEG_BOUNDARY(addr1, addr2, mask) \ | ||
205 | (((addr1) | (mask)) == (((addr2) - 1) | (mask))) | ||
206 | #define BIOVEC_SEG_BOUNDARY(q, b1, b2) \ | ||
207 | __BIO_SEG_BOUNDARY(bvec_to_phys((b1)), bvec_to_phys((b2)) + (b2)->bv_len, (q)->seg_boundary_mask) | ||
208 | #define BIO_SEG_BOUNDARY(q, b1, b2) \ | ||
209 | BIOVEC_SEG_BOUNDARY((q), __BVEC_END((b1)), __BVEC_START((b2))) | ||
210 | |||
211 | #define bio_io_error(bio, bytes) bio_endio((bio), (bytes), -EIO) | ||
212 | |||
213 | /* | ||
214 | * drivers should not use the __ version unless they _really_ want to | ||
215 | * run through the entire bio and not just pending pieces | ||
216 | */ | ||
217 | #define __bio_for_each_segment(bvl, bio, i, start_idx) \ | ||
218 | for (bvl = bio_iovec_idx((bio), (start_idx)), i = (start_idx); \ | ||
219 | i < (bio)->bi_vcnt; \ | ||
220 | bvl++, i++) | ||
221 | |||
222 | #define bio_for_each_segment(bvl, bio, i) \ | ||
223 | __bio_for_each_segment(bvl, bio, i, (bio)->bi_idx) | ||
224 | |||
225 | /* | ||
226 | * get a reference to a bio, so it won't disappear. the intended use is | ||
227 | * something like: | ||
228 | * | ||
229 | * bio_get(bio); | ||
230 | * submit_bio(rw, bio); | ||
231 | * if (bio->bi_flags ...) | ||
232 | * do_something | ||
233 | * bio_put(bio); | ||
234 | * | ||
235 | * without the bio_get(), it could potentially complete I/O before submit_bio | ||
236 | * returns. and then bio would be freed memory when if (bio->bi_flags ...) | ||
237 | * runs | ||
238 | */ | ||
239 | #define bio_get(bio) atomic_inc(&(bio)->bi_cnt) | ||
240 | |||
241 | |||
242 | /* | ||
243 | * A bio_pair is used when we need to split a bio. | ||
244 | * This can only happen for a bio that refers to just one | ||
245 | * page of data, and in the unusual situation when the | ||
246 | * page crosses a chunk/device boundary | ||
247 | * | ||
248 | * The address of the master bio is stored in bio1.bi_private | ||
249 | * The address of the pool the pair was allocated from is stored | ||
250 | * in bio2.bi_private | ||
251 | */ | ||
252 | struct bio_pair { | ||
253 | struct bio bio1, bio2; | ||
254 | struct bio_vec bv1, bv2; | ||
255 | atomic_t cnt; | ||
256 | int error; | ||
257 | }; | ||
258 | extern struct bio_pair *bio_split(struct bio *bi, mempool_t *pool, | ||
259 | int first_sectors); | ||
260 | extern mempool_t *bio_split_pool; | ||
261 | extern void bio_pair_release(struct bio_pair *dbio); | ||
262 | |||
263 | extern struct bio_set *bioset_create(int, int, int); | ||
264 | extern void bioset_free(struct bio_set *); | ||
265 | |||
266 | extern struct bio *bio_alloc(unsigned int __nocast, int); | ||
267 | extern struct bio *bio_alloc_bioset(unsigned int __nocast, int, struct bio_set *); | ||
268 | extern void bio_put(struct bio *); | ||
269 | |||
270 | extern void bio_endio(struct bio *, unsigned int, int); | ||
271 | struct request_queue; | ||
272 | extern int bio_phys_segments(struct request_queue *, struct bio *); | ||
273 | extern int bio_hw_segments(struct request_queue *, struct bio *); | ||
274 | |||
275 | extern void __bio_clone(struct bio *, struct bio *); | ||
276 | extern struct bio *bio_clone(struct bio *, unsigned int __nocast); | ||
277 | |||
278 | extern void bio_init(struct bio *); | ||
279 | |||
280 | extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int); | ||
281 | extern int bio_get_nr_vecs(struct block_device *); | ||
282 | extern struct bio *bio_map_user(struct request_queue *, struct block_device *, | ||
283 | unsigned long, unsigned int, int); | ||
284 | extern void bio_unmap_user(struct bio *); | ||
285 | extern void bio_set_pages_dirty(struct bio *bio); | ||
286 | extern void bio_check_pages_dirty(struct bio *bio); | ||
287 | extern struct bio *bio_copy_user(struct request_queue *, unsigned long, unsigned int, int); | ||
288 | extern int bio_uncopy_user(struct bio *); | ||
289 | void zero_fill_bio(struct bio *bio); | ||
290 | |||
291 | #ifdef CONFIG_HIGHMEM | ||
292 | /* | ||
293 | * remember to add offset! and never ever reenable interrupts between a | ||
294 | * bvec_kmap_irq and bvec_kunmap_irq!! | ||
295 | * | ||
296 | * This function MUST be inlined - it plays with the CPU interrupt flags. | ||
297 | * Hence the `extern inline'. | ||
298 | */ | ||
299 | extern inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags) | ||
300 | { | ||
301 | unsigned long addr; | ||
302 | |||
303 | /* | ||
304 | * might not be a highmem page, but the preempt/irq count | ||
305 | * balancing is a lot nicer this way | ||
306 | */ | ||
307 | local_irq_save(*flags); | ||
308 | addr = (unsigned long) kmap_atomic(bvec->bv_page, KM_BIO_SRC_IRQ); | ||
309 | |||
310 | BUG_ON(addr & ~PAGE_MASK); | ||
311 | |||
312 | return (char *) addr + bvec->bv_offset; | ||
313 | } | ||
314 | |||
315 | extern inline void bvec_kunmap_irq(char *buffer, unsigned long *flags) | ||
316 | { | ||
317 | unsigned long ptr = (unsigned long) buffer & PAGE_MASK; | ||
318 | |||
319 | kunmap_atomic((void *) ptr, KM_BIO_SRC_IRQ); | ||
320 | local_irq_restore(*flags); | ||
321 | } | ||
322 | |||
323 | #else | ||
324 | #define bvec_kmap_irq(bvec, flags) (page_address((bvec)->bv_page) + (bvec)->bv_offset) | ||
325 | #define bvec_kunmap_irq(buf, flags) do { *(flags) = 0; } while (0) | ||
326 | #endif | ||
327 | |||
328 | extern inline char *__bio_kmap_irq(struct bio *bio, unsigned short idx, | ||
329 | unsigned long *flags) | ||
330 | { | ||
331 | return bvec_kmap_irq(bio_iovec_idx(bio, idx), flags); | ||
332 | } | ||
333 | #define __bio_kunmap_irq(buf, flags) bvec_kunmap_irq(buf, flags) | ||
334 | |||
335 | #define bio_kmap_irq(bio, flags) \ | ||
336 | __bio_kmap_irq((bio), (bio)->bi_idx, (flags)) | ||
337 | #define bio_kunmap_irq(buf,flags) __bio_kunmap_irq(buf, flags) | ||
338 | |||
339 | #endif /* __LINUX_BIO_H */ | ||