diff options
| author | Ming Lei <ming.lei@redhat.com> | 2019-02-15 19:13:14 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2019-02-15 08:40:11 -0700 |
| commit | 45a3fb95298b326ab8175f2bd97bd8666017b692 (patch) | |
| tree | 2f613b6fcee60b90ecb3fb9a4371fab448cf9427 /include/linux/bvec.h | |
| parent | 862e5a5e6fa2c7fd514c179e9ceea27a49a3327f (diff) | |
block: introduce mp_bvec_last_segment()
BTRFS and guard_bio_eod() need to get the last singlepage segment
from one multipage bvec, so introduce this helper to make them happy.
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include/linux/bvec.h')
| -rw-r--r-- | include/linux/bvec.h | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/include/linux/bvec.h b/include/linux/bvec.h index 0ae729b1c9fe..21f76bad7be2 100644 --- a/include/linux/bvec.h +++ b/include/linux/bvec.h @@ -131,4 +131,26 @@ static inline bool bvec_iter_advance(const struct bio_vec *bv, .bi_bvec_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 = nth_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 */ |