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 V13 12/19] block: loop: pass multi-page bvec to iov_iter
Date: Fri, 11 Jan 2019 19:01:20 +0800 [thread overview]
Message-ID: <20190111110127.21664-13-ming.lei@redhat.com> (raw)
In-Reply-To: <20190111110127.21664-1-ming.lei@redhat.com>
iov_iter is implemented on bvec itererator helpers, so it is safe to pass
multi-page bvec to it, and this way is much more efficient than passing one
page in each bvec.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
drivers/block/loop.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index b8a0720d3653..28dd22c6f83f 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -511,21 +511,22 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd,
loff_t pos, bool rw)
{
struct iov_iter iter;
+ struct req_iterator rq_iter;
struct bio_vec *bvec;
struct request *rq = blk_mq_rq_from_pdu(cmd);
struct bio *bio = rq->bio;
struct file *file = lo->lo_backing_file;
+ struct bio_vec tmp;
unsigned int offset;
- int segments = 0;
+ int nr_bvec = 0;
int ret;
+ rq_for_each_bvec(tmp, rq, rq_iter)
+ nr_bvec++;
+
if (rq->bio != rq->biotail) {
- struct req_iterator iter;
- struct bio_vec tmp;
- __rq_for_each_bio(bio, rq)
- segments += bio_segments(bio);
- bvec = kmalloc_array(segments, sizeof(struct bio_vec),
+ bvec = kmalloc_array(nr_bvec, sizeof(struct bio_vec),
GFP_NOIO);
if (!bvec)
return -EIO;
@@ -534,10 +535,10 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd,
/*
* The bios of the request may be started from the middle of
* the 'bvec' because of bio splitting, so we can't directly
- * copy bio->bi_iov_vec to new bvec. The rq_for_each_segment
+ * copy bio->bi_iov_vec to new bvec. The rq_for_each_bvec
* API will take care of all details for us.
*/
- rq_for_each_segment(tmp, rq, iter) {
+ rq_for_each_bvec(tmp, rq, rq_iter) {
*bvec = tmp;
bvec++;
}
@@ -551,11 +552,10 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd,
*/
offset = bio->bi_iter.bi_bvec_done;
bvec = __bvec_iter_bvec(bio->bi_io_vec, bio->bi_iter);
- segments = bio_segments(bio);
}
atomic_set(&cmd->ref, 2);
- iov_iter_bvec(&iter, rw, bvec, segments, blk_rq_bytes(rq));
+ iov_iter_bvec(&iter, rw, bvec, nr_bvec, blk_rq_bytes(rq));
iter.iov_offset = offset;
cmd->iocb.ki_pos = pos;
--
2.9.5
next prev parent reply other threads:[~2019-01-11 11:04 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-11 11:01 [PATCH V13 00/19] block: support multi-page bvec Ming Lei
2019-01-11 11:01 ` [PATCH V13 01/19] btrfs: look at bi_size for repair decisions Ming Lei
2019-01-11 11:01 ` [PATCH V13 02/19] block: don't use bio->bi_vcnt to figure out segment number Ming Lei
2019-01-11 11:01 ` [PATCH V13 03/19] block: remove bvec_iter_rewind() Ming Lei
2019-01-11 11:01 ` [PATCH V13 04/19] block: rename bvec helpers Ming Lei
2019-01-11 11:01 ` [PATCH V13 05/19] block: introduce multi-page " Ming Lei
2019-01-11 11:01 ` [PATCH V13 06/19] block: introduce bio_for_each_bvec() and rq_for_each_bvec() Ming Lei
2019-01-11 11:01 ` [PATCH V13 07/19] block: use bio_for_each_bvec() to compute multi-page bvec count Ming Lei
2019-01-11 11:01 ` [PATCH V13 08/19] block: use bio_for_each_bvec() to map sg Ming Lei
2019-01-11 11:01 ` [PATCH V13 09/19] block: introduce bvec_last_segment() Ming Lei
2019-01-11 11:01 ` [PATCH V13 10/19] fs/buffer.c: use bvec iterator to truncate the bio Ming Lei
2019-01-11 11:01 ` [PATCH V13 11/19] btrfs: use bvec_last_segment to get bio's last page Ming Lei
2019-01-11 11:01 ` Ming Lei [this message]
2019-01-11 11:01 ` [PATCH V13 13/19] bcache: avoid to use bio_for_each_segment_all() in bch_bio_alloc_pages() Ming Lei
2019-01-11 11:01 ` [PATCH V13 14/19] block: allow bio_for_each_segment_all() to iterate over multi-page bvec Ming Lei
2019-01-11 11:01 ` [PATCH V13 15/19] block: enable multipage bvecs Ming Lei
2019-01-11 11:01 ` [PATCH V13 16/19] block: always define BIO_MAX_PAGES as 256 Ming Lei
2019-01-11 11:01 ` [PATCH V13 17/19] block: document usage of bio iterator helpers Ming Lei
2019-01-11 11:01 ` [PATCH V13 18/19] block: kill QUEUE_FLAG_NO_SG_MERGE Ming Lei
2019-01-11 11:01 ` [PATCH V13 19/19] block: kill BLK_MQ_F_SG_MERGE Ming Lei
2019-01-15 3:44 ` [PATCH V13 00/19] block: support multi-page bvec Jens Axboe
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