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8fc55455 ML |
1 | /* |
2 | * bvec iterator | |
3 | * | |
4 | * Copyright (C) 2001 Ming Lei <ming.lei@canonical.com> | |
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_BVEC_ITER_H | |
21 | #define __LINUX_BVEC_ITER_H | |
22 | ||
23 | #include <linux/blk_types.h> | |
24 | ||
25 | /* | |
26 | * various member access, note that bio_data should of course not be used | |
27 | * on highmem page vectors | |
28 | */ | |
29 | #define __bvec_iter_bvec(bvec, iter) (&(bvec)[(iter).bi_idx]) | |
30 | ||
31 | #define bvec_iter_page(bvec, iter) \ | |
32 | (__bvec_iter_bvec((bvec), (iter))->bv_page) | |
33 | ||
34 | #define bvec_iter_len(bvec, iter) \ | |
35 | min((iter).bi_size, \ | |
36 | __bvec_iter_bvec((bvec), (iter))->bv_len - (iter).bi_bvec_done) | |
37 | ||
38 | #define bvec_iter_offset(bvec, iter) \ | |
39 | (__bvec_iter_bvec((bvec), (iter))->bv_offset + (iter).bi_bvec_done) | |
40 | ||
41 | #define bvec_iter_bvec(bvec, iter) \ | |
42 | ((struct bio_vec) { \ | |
43 | .bv_page = bvec_iter_page((bvec), (iter)), \ | |
44 | .bv_len = bvec_iter_len((bvec), (iter)), \ | |
45 | .bv_offset = bvec_iter_offset((bvec), (iter)), \ | |
46 | }) | |
47 | ||
48 | static inline void bvec_iter_advance(struct bio_vec *bv, struct bvec_iter *iter, | |
49 | unsigned bytes) | |
50 | { | |
51 | WARN_ONCE(bytes > iter->bi_size, | |
52 | "Attempted to advance past end of bvec iter\n"); | |
53 | ||
54 | while (bytes) { | |
55 | unsigned len = min(bytes, bvec_iter_len(bv, *iter)); | |
56 | ||
57 | bytes -= len; | |
58 | iter->bi_size -= len; | |
59 | iter->bi_bvec_done += len; | |
60 | ||
61 | if (iter->bi_bvec_done == __bvec_iter_bvec(bv, *iter)->bv_len) { | |
62 | iter->bi_bvec_done = 0; | |
63 | iter->bi_idx++; | |
64 | } | |
65 | } | |
66 | } | |
67 | ||
68 | #define for_each_bvec(bvl, bio_vec, iter, start) \ | |
69 | for (iter = (start); \ | |
70 | (iter).bi_size && \ | |
71 | ((bvl = bvec_iter_bvec((bio_vec), (iter))), 1); \ | |
72 | bvec_iter_advance((bio_vec), &(iter), (bvl).bv_len)) | |
73 | ||
74 | #endif /* __LINUX_BVEC_ITER_H */ |