Файловый менеджер

Файловый менеджер - Редактировать - /usr/src/linux-headers-5.4.0-200/include/linux/bvec.h

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/* SPDX-License-Identifier: GPL-2.0 / / * bvec iterator * * Copyright (C) 2001 Ming Lei <ming.lei@canonical.com> / #ifndef __LINUX_BVEC_ITER_H #define __LINUX_BVEC_ITER_H #include <linux/kernel.h> #include <linux/bug.h> #include <linux/errno.h> #include <linux/mm.h> / * was unsigned short, but we might as well be ready for > 64kB I/O pages / struct bio_vec { struct page bv_page; unsigned int bv_len; unsigned int bv_offset; }; struct bvec_iter { sector_t bi_sector; /* device address in 512 byte sectors / unsigned int bi_size; / residual I/O count / unsigned int bi_idx; / current index into bvl_vec / unsigned int bi_bvec_done; / number of bytes completed in current bvec / }; struct bvec_iter_all { struct bio_vec bv; int idx; unsigned done; }; / * various member access, note that bio_data should of course not be used * on highmem page vectors / #define __bvec_iter_bvec(bvec, iter) (&(bvec)[(iter).bi_idx]) / multi-page (mp_bvec) helpers / #define mp_bvec_iter_page(bvec, iter) \ (__bvec_iter_bvec((bvec), (iter))->bv_page) #define mp_bvec_iter_len(bvec, iter) \ min((iter).bi_size, \ __bvec_iter_bvec((bvec), (iter))->bv_len - (iter).bi_bvec_done) #define mp_bvec_iter_offset(bvec, iter) \ (__bvec_iter_bvec((bvec), (iter))->bv_offset + (iter).bi_bvec_done) #define mp_bvec_iter_page_idx(bvec, iter) \ (mp_bvec_iter_offset((bvec), (iter)) / PAGE_SIZE) #define mp_bvec_iter_bvec(bvec, iter) \ ((struct bio_vec) { \ .bv_page = mp_bvec_iter_page((bvec), (iter)), \ .bv_len = mp_bvec_iter_len((bvec), (iter)), \ .bv_offset = mp_bvec_iter_offset((bvec), (iter)), \ }) / For building single-page bvec in flight / #define bvec_iter_offset(bvec, iter) \ (mp_bvec_iter_offset((bvec), (iter)) % PAGE_SIZE) #define bvec_iter_len(bvec, iter) \ min_t(unsigned, mp_bvec_iter_len((bvec), (iter)), \ PAGE_SIZE - bvec_iter_offset((bvec), (iter))) #define bvec_iter_page(bvec, iter) \ (mp_bvec_iter_page((bvec), (iter)) + \ mp_bvec_iter_page_idx((bvec), (iter))) #define bvec_iter_bvec(bvec, iter) \ ((struct bio_vec) { \ .bv_page = bvec_iter_page((bvec), (iter)), \ .bv_len = bvec_iter_len((bvec), (iter)), \ .bv_offset = bvec_iter_offset((bvec), (iter)), \ }) static inline bool bvec_iter_advance(const struct bio_vec bv, struct bvec_iter iter, unsigned bytes) { if (WARN_ONCE(bytes > iter->bi_size, "Attempted to advance past end of bvec iter\n")) { iter->bi_size = 0; return false; } while (bytes) { const struct bio_vec cur = bv + iter->bi_idx; unsigned len = min3(bytes, iter->bi_size, cur->bv_len - iter->bi_bvec_done); bytes -= len; iter->bi_size -= len; iter->bi_bvec_done += len; if (iter->bi_bvec_done == cur->bv_len) { iter->bi_bvec_done = 0; iter->bi_idx++; } } return true; } static inline void bvec_iter_skip_zero_bvec(struct bvec_iter iter) { iter->bi_bvec_done = 0; iter->bi_idx++; } #define for_each_bvec(bvl, bio_vec, iter, start) \ for (iter = (start); \ (iter).bi_size && \ ((bvl = bvec_iter_bvec((bio_vec), (iter))), 1); \ (bvl).bv_len ? (void)bvec_iter_advance((bio_vec), &(iter), \ (bvl).bv_len) : bvec_iter_skip_zero_bvec(&(iter))) / for iterating one bio from start to end / #define BVEC_ITER_ALL_INIT (struct bvec_iter) \ { \ .bi_sector = 0, \ .bi_size = UINT_MAX, \ .bi_idx = 0, \ .bi_bvec_done = 0, \ } static inline struct bio_vec bvec_init_iter_all(struct bvec_iter_all iter_all) { iter_all->done = 0; iter_all->idx = 0; return &iter_all->bv; } static inline void bvec_advance(const struct bio_vec bvec, struct bvec_iter_all iter_all) { struct bio_vec bv = &iter_all->bv; if (iter_all->done) { bv->bv_page++; bv->bv_offset = 0; } else { bv->bv_page = bvec->bv_page + (bvec->bv_offset >> PAGE_SHIFT); bv->bv_offset = bvec->bv_offset & ~PAGE_MASK; } bv->bv_len = min_t(unsigned int, PAGE_SIZE - bv->bv_offset, bvec->bv_len - iter_all->done); iter_all->done += bv->bv_len; if (iter_all->done == bvec->bv_len) { iter_all->idx++; iter_all->done = 0; } } /* * Get the last single-page segment from the multi-page bvec and store it * in @seg / static inline void mp_bvec_last_segment(const struct bio_vec bvec, struct bio_vec seg) { unsigned total = bvec->bv_offset + bvec->bv_len; unsigned last_page = (total - 1) / PAGE_SIZE; seg->bv_page = bvec->bv_page + last_page; / the whole segment is inside the last page / if (bvec->bv_offset >= last_page PAGE_SIZE) { seg->bv_offset = bvec->bv_offset % PAGE_SIZE; seg->bv_len = bvec->bv_len; } else { seg->bv_offset = 0; seg->bv_len = total - last_page * PAGE_SIZE; } } #endif /* __LINUX_BVEC_ITER_H */

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