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| author | Ming Lei <ming.lei@redhat.com> | 2019-02-27 13:40:10 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2019-02-27 14:18:52 +0100 |
| commit | 4d633062c1c0794a6b3836b7b55afba4599736e8 (patch) | |
| tree | 548fd74a24fae2181f63fdde531ff63cc953d6c5 /include/linux/bvec.h | |
| parent | iomap: wire up the iopoll method (diff) | |
| download | linux-4d633062c1c0794a6b3836b7b55afba4599736e8.tar.xz linux-4d633062c1c0794a6b3836b7b55afba4599736e8.zip | |
block: introduce bvec_nth_page()
Single-page bvec can often be seen in small BS workloads, so
introduce bvec_nth_page() for avoiding to call nth_page() unnecessarily,
which looks not cheap.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to '')
| -rw-r--r-- | include/linux/bvec.h | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/include/linux/bvec.h b/include/linux/bvec.h index 30a57b68d017..4376f683c08a 100644 --- a/include/linux/bvec.h +++ b/include/linux/bvec.h @@ -51,6 +51,11 @@ struct bvec_iter_all { unsigned done; }; +static inline struct page *bvec_nth_page(struct page *page, int idx) +{ + return idx == 0 ? page : nth_page(page, idx); +} + /* * various member access, note that bio_data should of course not be used * on highmem page vectors @@ -87,8 +92,8 @@ struct bvec_iter_all { PAGE_SIZE - bvec_iter_offset((bvec), (iter))) #define bvec_iter_page(bvec, iter) \ - nth_page(mp_bvec_iter_page((bvec), (iter)), \ - mp_bvec_iter_page_idx((bvec), (iter))) + bvec_nth_page(mp_bvec_iter_page((bvec), (iter)), \ + mp_bvec_iter_page_idx((bvec), (iter))) #define bvec_iter_bvec(bvec, iter) \ ((struct bio_vec) { \ @@ -171,7 +176,7 @@ static inline void mp_bvec_last_segment(const struct bio_vec *bvec, unsigned total = bvec->bv_offset + bvec->bv_len; unsigned last_page = (total - 1) / PAGE_SIZE; - seg->bv_page = nth_page(bvec->bv_page, last_page); + seg->bv_page = bvec_nth_page(bvec->bv_page, last_page); /* the whole segment is inside the last page */ if (bvec->bv_offset >= last_page * PAGE_SIZE) { |