| Ming Lei | 8fc5545 | 2016-06-09 10:00:58 -0600 | [diff] [blame^] | 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 */ |