BTRFS and guard_bio_eod() need to get the last singlepage segment from one multipage bvec, so introduce this helper to make them happy.
Cc: Dave Chinner <dchin...@redhat.com> Cc: Kent Overstreet <kent.overstr...@gmail.com> Cc: Mike Snitzer <snit...@redhat.com> Cc: dm-de...@redhat.com Cc: Alexander Viro <v...@zeniv.linux.org.uk> Cc: linux-fsde...@vger.kernel.org Cc: Shaohua Li <s...@kernel.org> Cc: linux-r...@vger.kernel.org Cc: linux-er...@lists.ozlabs.org Cc: David Sterba <dste...@suse.com> Cc: linux-bt...@vger.kernel.org Cc: Darrick J. Wong <darrick.w...@oracle.com> Cc: linux-...@vger.kernel.org Cc: Gao Xiang <gaoxian...@huawei.com> Cc: Christoph Hellwig <h...@lst.de> Cc: Theodore Ts'o <ty...@mit.edu> Cc: linux-e...@vger.kernel.org Cc: Coly Li <col...@suse.de> Cc: linux-bca...@vger.kernel.org Cc: Boaz Harrosh <o...@electrozaur.com> Cc: Bob Peterson <rpete...@redhat.com> Cc: cluster-devel@redhat.com Signed-off-by: Ming Lei <ming....@redhat.com> --- include/linux/bvec.h | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/include/linux/bvec.h b/include/linux/bvec.h index 3d61352cd8cf..01616a0b6220 100644 --- a/include/linux/bvec.h +++ b/include/linux/bvec.h @@ -216,4 +216,29 @@ static inline bool mp_bvec_iter_advance(const struct bio_vec *bv, .bi_bvec_done = 0, \ } +/* + * Get the last singlepage segment from the multipage bvec and store it + * in @seg + */ +static inline void bvec_last_segment(const struct bio_vec *bvec, + struct bio_vec *seg) +{ + unsigned total = bvec->bv_offset + bvec->bv_len; + unsigned last_page = total / PAGE_SIZE; + + if (last_page * PAGE_SIZE == total) + last_page--; + + 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 */ -- 2.9.5