diff options
| -rw-r--r-- | block/bio.c | 60 | ||||
| -rw-r--r-- | include/linux/bio.h | 2 |
2 files changed, 49 insertions, 13 deletions
diff --git a/block/bio.c b/block/bio.c index e75878f8b14a..1ccff0dace89 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1025,19 +1025,8 @@ int bio_alloc_pages(struct bio *bio, gfp_t gfp_mask) } EXPORT_SYMBOL(bio_alloc_pages); -/** - * bio_copy_data - copy contents of data buffers from one chain of bios to - * another - * @src: source bio list - * @dst: destination bio list - * - * If @src and @dst are single bios, bi_next must be NULL - otherwise, treats - * @src and @dst as linked lists of bios. - * - * Stops when it reaches the end of either @src or @dst - that is, copies - * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios). - */ -void bio_copy_data(struct bio *dst, struct bio *src) +static void __bio_copy_data(struct bio *dst, struct bio *src, + int offset, int size) { struct bvec_iter src_iter, dst_iter; struct bio_vec src_bv, dst_bv; @@ -1047,6 +1036,12 @@ void bio_copy_data(struct bio *dst, struct bio *src) src_iter = src->bi_iter; dst_iter = dst->bi_iter; + /* for supporting partial copy */ + if (offset || size != src->bi_iter.bi_size) { + bio_advance_iter(src, &src_iter, offset); + src_iter.bi_size = size; + } + while (1) { if (!src_iter.bi_size) { src = src->bi_next; @@ -1083,8 +1078,47 @@ void bio_copy_data(struct bio *dst, struct bio *src) bio_advance_iter(dst, &dst_iter, bytes); } } + +/** + * bio_copy_data - copy contents of data buffers from one chain of bios to + * another + * @src: source bio list + * @dst: destination bio list + * + * If @src and @dst are single bios, bi_next must be NULL - otherwise, treats + * @src and @dst as linked lists of bios. + * + * Stops when it reaches the end of either @src or @dst - that is, copies + * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios). + */ +void bio_copy_data(struct bio *dst, struct bio *src) +{ + __bio_copy_data(dst, src, 0, src->bi_iter.bi_size); +} EXPORT_SYMBOL(bio_copy_data); +/** + * bio_copy_data_partial - copy partial contents of data buffers from one + * chain of bios to another + * @dst: destination bio list + * @src: source bio list + * @offset: starting copy from the offset + * @size: how many bytes to copy + * + * If @src and @dst are single bios, bi_next must be NULL - otherwise, treats + * @src and @dst as linked lists of bios. + * + * Stops when it reaches the end of either @src or @dst - that is, copies + * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios). + */ +void bio_copy_data_partial(struct bio *dst, struct bio *src, + int offset, int size) +{ + __bio_copy_data(dst, src, offset, size); + +} +EXPORT_SYMBOL(bio_copy_data_partial); + struct bio_map_data { int is_our_pages; struct iov_iter iter; diff --git a/include/linux/bio.h b/include/linux/bio.h index 8e521194f6fc..42b62a0288b0 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -468,6 +468,8 @@ static inline void bio_flush_dcache_pages(struct bio *bi) #endif extern void bio_copy_data(struct bio *dst, struct bio *src); +extern void bio_copy_data_partial(struct bio *dst, struct bio *src, + int offset, int size); extern int bio_alloc_pages(struct bio *bio, gfp_t gfp); extern void bio_free_pages(struct bio *bio); |