This helper is used to iterate multipage bvec for bio spliting/merge, and it is required in bio_clone_bioset() too, so introduce it. Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx> --- include/linux/bio.h | 34 +++++++++++++++++++++++++++++++--- include/linux/bvec.h | 36 ++++++++++++++++++++++++++++++++---- 2 files changed, 63 insertions(+), 7 deletions(-) diff --git a/include/linux/bio.h b/include/linux/bio.h index 95ca5ddc72ef..0cb29c73ff27 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -76,6 +76,9 @@ #define bio_data_dir(bio) \ (op_is_write(bio_op(bio)) ? WRITE : READ) +#define bio_iter_seg_iovec(bio, iter) \ + bvec_iter_segment_bvec((bio)->bi_io_vec, (iter)) + /* * Check whether this bio carries any data or not. A NULL bio is allowed. */ @@ -156,8 +159,8 @@ static inline void *bio_data(struct bio *bio) #define bio_for_each_page_all(bvl, bio, i) \ for (i = 0, bvl = (bio)->bi_io_vec; i < (bio)->bi_vcnt; i++, bvl++) -static inline void bio_advance_iter(struct bio *bio, struct bvec_iter *iter, - unsigned bytes) +static inline void __bio_advance_iter(struct bio *bio, struct bvec_iter *iter, + unsigned bytes, bool seg) { iter->bi_sector += bytes >> 9; @@ -165,11 +168,26 @@ static inline void bio_advance_iter(struct bio *bio, struct bvec_iter *iter, iter->bi_size -= bytes; iter->bi_done += bytes; } else { - bvec_iter_advance(bio->bi_io_vec, iter, bytes); + if (!seg) + bvec_iter_advance(bio->bi_io_vec, iter, bytes); + else + bvec_iter_seg_advance(bio->bi_io_vec, iter, bytes); /* TODO: It is reasonable to complete bio with error here. */ } } +static inline void bio_advance_iter(struct bio *bio, struct bvec_iter *iter, + unsigned bytes) +{ + __bio_advance_iter(bio, iter, bytes, false); +} + +static inline void bio_advance_seg_iter(struct bio *bio, struct bvec_iter *iter, + unsigned bytes) +{ + __bio_advance_iter(bio, iter, bytes, true); +} + static inline bool bio_rewind_iter(struct bio *bio, struct bvec_iter *iter, unsigned int bytes) { @@ -193,6 +211,16 @@ static inline bool bio_rewind_iter(struct bio *bio, struct bvec_iter *iter, #define bio_for_each_page(bvl, bio, iter) \ __bio_for_each_page(bvl, bio, iter, (bio)->bi_iter) +#define __bio_for_each_segment(bvl, bio, iter, start) \ + for (iter = (start); \ + (iter).bi_size && \ + ((bvl = bio_iter_seg_iovec((bio), (iter))), 1); \ + bio_advance_seg_iter((bio), &(iter), (bvl).bv_len)) + +/* returns one real segment(multipage bvec) each time */ +#define bio_for_each_segment(bvl, bio, iter) \ + __bio_for_each_segment(bvl, bio, iter, (bio)->bi_iter) + #define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len) static inline unsigned bio_pages(struct bio *bio) diff --git a/include/linux/bvec.h b/include/linux/bvec.h index 2433c73fa5ea..84c395feed49 100644 --- a/include/linux/bvec.h +++ b/include/linux/bvec.h @@ -126,8 +126,16 @@ struct 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) +#define bvec_iter_segment_bvec(bvec, iter) \ +((struct bio_vec) { \ + .bv_page = bvec_iter_segment_page((bvec), (iter)), \ + .bv_len = bvec_iter_segment_len((bvec), (iter)), \ + .bv_offset = bvec_iter_segment_offset((bvec), (iter)), \ +}) + +static inline bool __bvec_iter_advance(const struct bio_vec *bv, + struct bvec_iter *iter, + unsigned bytes, bool segment) { if (WARN_ONCE(bytes > iter->bi_size, "Attempted to advance past end of bvec iter\n")) { @@ -136,8 +144,14 @@ static inline bool bvec_iter_advance(const struct bio_vec *bv, } while (bytes) { - unsigned iter_len = bvec_iter_len(bv, *iter); - unsigned len = min(bytes, iter_len); + unsigned len; + + if (segment) + len = bvec_iter_segment_len(bv, *iter); + else + len = bvec_iter_len(bv, *iter); + + len = min(bytes, len); bytes -= len; iter->bi_size -= len; @@ -176,6 +190,20 @@ static inline bool bvec_iter_rewind(const struct bio_vec *bv, return true; } +static inline bool bvec_iter_advance(const struct bio_vec *bv, + struct bvec_iter *iter, + unsigned bytes) +{ + return __bvec_iter_advance(bv, iter, bytes, false); +} + +static inline bool bvec_iter_seg_advance(const struct bio_vec *bv, + struct bvec_iter *iter, + unsigned bytes) +{ + return __bvec_iter_advance(bv, iter, bytes, true); +} + #define for_each_bvec(bvl, bio_vec, iter, start) \ for (iter = (start); \ (iter).bi_size && \ -- 2.9.5