diff options
Diffstat (limited to 'include/linux/bvec.h')
| -rw-r--r-- | include/linux/bvec.h | 104 |
1 files changed, 96 insertions, 8 deletions
diff --git a/include/linux/bvec.h b/include/linux/bvec.h index a81c13ac1972..35c25dff651a 100644 --- a/include/linux/bvec.h +++ b/include/linux/bvec.h @@ -4,16 +4,30 @@ * * Copyright (C) 2001 Ming Lei <ming.lei@canonical.com> */ -#ifndef __LINUX_BVEC_ITER_H -#define __LINUX_BVEC_ITER_H +#ifndef __LINUX_BVEC_H +#define __LINUX_BVEC_H -#include <linux/kernel.h> +#include <linux/highmem.h> #include <linux/bug.h> #include <linux/errno.h> +#include <linux/limits.h> +#include <linux/minmax.h> #include <linux/mm.h> +#include <linux/types.h> -/* - * was unsigned short, but we might as well be ready for > 64kB I/O pages +struct page; + +/** + * struct bio_vec - a contiguous range of physical memory addresses + * @bv_page: First page associated with the address range. + * @bv_len: Number of bytes in the address range. + * @bv_offset: Start of the address range relative to the start of @bv_page. + * + * The following holds for a bvec if n * PAGE_SIZE < bv_offset + bv_len: + * + * nth_page(@bv_page, n) == @bv_page + n + * + * This holds because page_is_mergeable() checks the above property. */ struct bio_vec { struct page *bv_page; @@ -30,7 +44,7 @@ struct bvec_iter { unsigned int bi_bvec_done; /* number of bytes completed in current bvec */ -}; +} __packed; struct bvec_iter_all { struct bio_vec bv; @@ -108,11 +122,28 @@ static inline bool bvec_iter_advance(const struct bio_vec *bv, return true; } +/* + * A simpler version of bvec_iter_advance(), @bytes should not span + * across multiple bvec entries, i.e. bytes <= bv[i->bi_idx].bv_len + */ +static inline void bvec_iter_advance_single(const struct bio_vec *bv, + struct bvec_iter *iter, unsigned int bytes) +{ + unsigned int done = iter->bi_bvec_done + bytes; + + if (done == bv[iter->bi_idx].bv_len) { + done = 0; + iter->bi_idx++; + } + iter->bi_bvec_done = done; + iter->bi_size -= bytes; +} + #define for_each_bvec(bvl, bio_vec, iter, start) \ for (iter = (start); \ (iter).bi_size && \ ((bvl = bvec_iter_bvec((bio_vec), (iter))), 1); \ - bvec_iter_advance((bio_vec), &(iter), (bvl).bv_len)) + bvec_iter_advance_single((bio_vec), &(iter), (bvl).bv_len)) /* for iterating one bio from start to end */ #define BVEC_ITER_ALL_INIT (struct bvec_iter) \ @@ -153,4 +184,61 @@ static inline void bvec_advance(const struct bio_vec *bvec, } } -#endif /* __LINUX_BVEC_ITER_H */ +/** + * bvec_kmap_local - map a bvec into the kernel virtual address space + * @bvec: bvec to map + * + * Must be called on single-page bvecs only. Call kunmap_local on the returned + * address to unmap. + */ +static inline void *bvec_kmap_local(struct bio_vec *bvec) +{ + return kmap_local_page(bvec->bv_page) + bvec->bv_offset; +} + +/** + * memcpy_from_bvec - copy data from a bvec + * @bvec: bvec to copy from + * + * Must be called on single-page bvecs only. + */ +static inline void memcpy_from_bvec(char *to, struct bio_vec *bvec) +{ + memcpy_from_page(to, bvec->bv_page, bvec->bv_offset, bvec->bv_len); +} + +/** + * memcpy_to_bvec - copy data to a bvec + * @bvec: bvec to copy to + * + * Must be called on single-page bvecs only. + */ +static inline void memcpy_to_bvec(struct bio_vec *bvec, const char *from) +{ + memcpy_to_page(bvec->bv_page, bvec->bv_offset, from, bvec->bv_len); +} + +/** + * memzero_bvec - zero all data in a bvec + * @bvec: bvec to zero + * + * Must be called on single-page bvecs only. + */ +static inline void memzero_bvec(struct bio_vec *bvec) +{ + memzero_page(bvec->bv_page, bvec->bv_offset, bvec->bv_len); +} + +/** + * bvec_virt - return the virtual address for a bvec + * @bvec: bvec to return the virtual address for + * + * Note: the caller must ensure that @bvec->bv_page is not a highmem page. + */ +static inline void *bvec_virt(struct bio_vec *bvec) +{ + WARN_ON_ONCE(PageHighMem(bvec->bv_page)); + return page_address(bvec->bv_page) + bvec->bv_offset; +} + +#endif /* __LINUX_BVEC_H */ |