From: Ming Lei <ming.lei@redhat.com> To: Jens Axboe <axboe@kernel.dk> Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Theodore Ts'o <tytso@mit.edu>, Omar Sandoval <osandov@fb.com>, Sagi Grimberg <sagi@grimberg.me>, Dave Chinner <dchinner@redhat.com>, Kent Overstreet <kent.overstreet@gmail.com>, Mike Snitzer <snitzer@redhat.com>, dm-devel@redhat.com, Alexander Viro <viro@zeniv.linux.org.uk>, linux-fsdevel@vger.kernel.org, linux-raid@vger.kernel.org, David Sterba <dsterba@suse.com>, linux-btrfs@vger.kernel.org, "Darrick J . Wong" <darrick.wong@oracle.com>, linux-xfs@vger.kernel.org, Gao Xiang <gaoxiang25@huawei.com>, Christoph Hellwig <hch@lst.de>, linux-ext4@vger.kernel.org, Coly Li <colyli@suse.de>, linux-bcache@vger.kernel.org, Boaz Harrosh <ooo@electrozaur.com>, Bob Peterson <rpeterso@redhat.com>, cluster-devel@redhat.com, Ming Lei <ming.lei@redhat.com> Subject: [PATCH V14 08/18] block: introduce mp_bvec_last_segment() Date: Mon, 21 Jan 2019 16:17:55 +0800 Message-ID: <20190121081805.32727-9-ming.lei@redhat.com> (raw) In-Reply-To: <20190121081805.32727-1-ming.lei@redhat.com> 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> --- include/linux/bvec.h | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) 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 */ -- 2.9.5
next prev parent reply index Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-01-21 8:17 [PATCH V14 00/18] block: support multi-page bvec Ming Lei 2019-01-21 8:17 ` [PATCH V14 01/18] btrfs: look at bi_size for repair decisions Ming Lei 2019-01-21 8:17 ` [PATCH V14 02/18] block: don't use bio->bi_vcnt to figure out segment number Ming Lei 2019-01-21 8:17 ` [PATCH V14 03/18] block: remove bvec_iter_rewind() Ming Lei 2019-01-21 8:17 ` [PATCH V14 04/18] block: introduce multi-page bvec helpers Ming Lei 2019-01-21 8:17 ` [PATCH V14 05/18] block: introduce bio_for_each_mp_bvec() and rq_for_each_mp_bvec() Ming Lei 2019-01-21 8:17 ` [PATCH V14 06/18] block: use bio_for_each_mp_bvec() to compute multi-page bvec count Ming Lei 2019-01-21 8:17 ` [PATCH V14 07/18] block: use bio_for_each_mp_bvec() to map sg Ming Lei 2019-01-21 8:17 ` Ming Lei [this message] 2019-01-21 8:17 ` [PATCH V14 09/18] fs/buffer.c: use bvec iterator to truncate the bio Ming Lei 2019-01-21 8:17 ` [PATCH V14 10/18] btrfs: use mp_bvec_last_segment to get bio's last page Ming Lei 2019-01-21 8:17 ` [PATCH V14 11/18] block: loop: pass multi-page bvec to iov_iter Ming Lei 2019-01-21 8:17 ` [PATCH V14 12/18] bcache: avoid to use bio_for_each_segment_all() in bch_bio_alloc_pages() Ming Lei 2019-01-21 8:18 ` [PATCH V14 13/18] block: allow bio_for_each_segment_all() to iterate over multi-page bvec Ming Lei 2019-01-21 8:18 ` [PATCH V14 14/18] block: enable multipage bvecs Ming Lei 2019-01-21 8:18 ` [PATCH V14 15/18] block: always define BIO_MAX_PAGES as 256 Ming Lei 2019-01-21 8:18 ` [PATCH V14 16/18] block: document usage of bio iterator helpers Ming Lei 2019-01-21 8:18 ` [PATCH V14 17/18] block: kill QUEUE_FLAG_NO_SG_MERGE Ming Lei 2019-01-21 8:18 ` [PATCH V14 18/18] block: kill BLK_MQ_F_SG_MERGE Ming Lei 2019-01-21 8:22 ` [PATCH V14 00/18] block: support multi-page bvec Christoph Hellwig 2019-01-21 8:37 ` Ming Lei 2019-01-21 8:38 ` Christoph Hellwig 2019-01-21 8:40 ` Ming Lei 2019-01-21 9:43 ` Sagi Grimberg 2019-01-22 2:01 ` Ming Lei
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