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97 lines
2.7 KiB
97 lines
2.7 KiB
/* |
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* bvec iterator |
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* |
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* Copyright (C) 2001 Ming Lei <[email protected]> |
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* |
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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License version 2 as |
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* published by the Free Software Foundation. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public Licens |
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* along with this program; if not, write to the Free Software |
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111- |
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*/ |
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#ifndef __LINUX_BVEC_ITER_H |
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#define __LINUX_BVEC_ITER_H |
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#include <linux/kernel.h> |
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#include <linux/bug.h> |
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/* |
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* was unsigned short, but we might as well be ready for > 64kB I/O pages |
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*/ |
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struct bio_vec { |
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struct page *bv_page; |
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unsigned int bv_len; |
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unsigned int bv_offset; |
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}; |
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struct bvec_iter { |
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sector_t bi_sector; /* device address in 512 byte |
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sectors */ |
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unsigned int bi_size; /* residual I/O count */ |
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unsigned int bi_idx; /* current index into bvl_vec */ |
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unsigned int bi_bvec_done; /* number of bytes completed in |
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current bvec */ |
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}; |
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/* |
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* various member access, note that bio_data should of course not be used |
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* on highmem page vectors |
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*/ |
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#define __bvec_iter_bvec(bvec, iter) (&(bvec)[(iter).bi_idx]) |
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#define bvec_iter_page(bvec, iter) \ |
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(__bvec_iter_bvec((bvec), (iter))->bv_page) |
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#define bvec_iter_len(bvec, iter) \ |
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min((iter).bi_size, \ |
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__bvec_iter_bvec((bvec), (iter))->bv_len - (iter).bi_bvec_done) |
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#define bvec_iter_offset(bvec, iter) \ |
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(__bvec_iter_bvec((bvec), (iter))->bv_offset + (iter).bi_bvec_done) |
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#define bvec_iter_bvec(bvec, iter) \ |
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((struct bio_vec) { \ |
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.bv_page = bvec_iter_page((bvec), (iter)), \ |
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.bv_len = bvec_iter_len((bvec), (iter)), \ |
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.bv_offset = bvec_iter_offset((bvec), (iter)), \ |
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}) |
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static inline void bvec_iter_advance(const struct bio_vec *bv, |
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struct bvec_iter *iter, |
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unsigned bytes) |
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{ |
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WARN_ONCE(bytes > iter->bi_size, |
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"Attempted to advance past end of bvec iter\n"); |
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while (bytes) { |
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unsigned iter_len = bvec_iter_len(bv, *iter); |
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unsigned len = min(bytes, iter_len); |
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bytes -= len; |
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iter->bi_size -= len; |
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iter->bi_bvec_done += len; |
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if (iter->bi_bvec_done == __bvec_iter_bvec(bv, *iter)->bv_len) { |
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iter->bi_bvec_done = 0; |
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iter->bi_idx++; |
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} |
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} |
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} |
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#define for_each_bvec(bvl, bio_vec, iter, start) \ |
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for (iter = (start); \ |
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(iter).bi_size && \ |
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((bvl = bvec_iter_bvec((bio_vec), (iter))), 1); \ |
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bvec_iter_advance((bio_vec), &(iter), (bvl).bv_len)) |
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#endif /* __LINUX_BVEC_ITER_H */
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