From: Ming Lei <ming.lei@redhat.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, 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, Shaohua Li <shli@kernel.org>,
linux-raid@vger.kernel.org, linux-erofs@lists.ozlabs.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>,
Theodore Ts'o <tytso@mit.edu>,
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
Subject: Re: [PATCH V10 09/19] block: introduce bio_bvecs()
Date: Mon, 19 Nov 2018 16:21:25 +0800 [thread overview]
Message-ID: <20181119082124.GC16736@ming.t460p> (raw)
In-Reply-To: <20181116134541.GH3165@lst.de>
On Fri, Nov 16, 2018 at 02:45:41PM +0100, Christoph Hellwig wrote:
> On Thu, Nov 15, 2018 at 04:52:56PM +0800, Ming Lei wrote:
> > There are still cases in which we need to use bio_bvecs() for get the
> > number of multi-page segment, so introduce it.
>
> The only user in your final tree seems to be the loop driver, and
> even that one only uses the helper for read/write bios.
>
> I think something like this would be much simpler in the end:
>
> diff --git a/drivers/block/loop.c b/drivers/block/loop.c
> index d509902a8046..712511815ac6 100644
> --- a/drivers/block/loop.c
> +++ b/drivers/block/loop.c
> @@ -514,16 +514,18 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd,
> struct request *rq = blk_mq_rq_from_pdu(cmd);
> struct bio *bio = rq->bio;
> struct file *file = lo->lo_backing_file;
> + struct bvec_iter bvec_iter;
> + struct bio_vec tmp;
> unsigned int offset;
> int nr_bvec = 0;
> int ret;
>
> + __rq_for_each_bio(bio, rq)
> + bio_for_each_bvec(tmp, bio, bvec_iter)
> + nr_bvec++;
> +
> if (rq->bio != rq->biotail) {
> - struct bvec_iter iter;
> - struct bio_vec tmp;
>
> - __rq_for_each_bio(bio, rq)
> - nr_bvec += bio_bvecs(bio);
> bvec = kmalloc_array(nr_bvec, sizeof(struct bio_vec),
> GFP_NOIO);
> if (!bvec)
> @@ -537,7 +539,7 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd,
> * API will take care of all details for us.
> */
> __rq_for_each_bio(bio, rq)
> - bio_for_each_bvec(tmp, bio, iter) {
> + bio_for_each_bvec(tmp, bio, bvec_iter) {
> *bvec = tmp;
> bvec++;
> }
> @@ -551,7 +553,6 @@ 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);
> - nr_bvec = bio_bvecs(bio);
> }
> atomic_set(&cmd->ref, 2);
>
> diff --git a/include/linux/bio.h b/include/linux/bio.h
> index dcad0b69f57a..379440d1ced0 100644
> --- a/include/linux/bio.h
> +++ b/include/linux/bio.h
> @@ -200,30 +200,6 @@ static inline unsigned bio_segments(struct bio *bio)
> }
> }
>
> -static inline unsigned bio_bvecs(struct bio *bio)
> -{
> - unsigned bvecs = 0;
> - struct bio_vec bv;
> - struct bvec_iter iter;
> -
> - /*
> - * We special case discard/write same/write zeroes, because they
> - * interpret bi_size differently:
> - */
> - switch (bio_op(bio)) {
> - case REQ_OP_DISCARD:
> - case REQ_OP_SECURE_ERASE:
> - case REQ_OP_WRITE_ZEROES:
> - return 0;
> - case REQ_OP_WRITE_SAME:
> - return 1;
> - default:
> - bio_for_each_bvec(bv, bio, iter)
> - bvecs++;
> - return bvecs;
> - }
> -}
> -
> /*
> * get a reference to a bio, so it won't disappear. the intended use is
> * something like:
OK, will do it in next version.
Thanks,
Ming
next prev parent reply other threads:[~2018-11-19 8:21 UTC|newest]
Thread overview: 103+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-15 8:52 [PATCH V10 00/19] block: support multi-page bvec Ming Lei
2018-11-15 8:52 ` [PATCH V10 01/19] block: introduce multi-page page bvec helpers Ming Lei
2018-11-15 18:25 ` Omar Sandoval
2018-11-19 2:25 ` Ming Lei
2018-11-16 13:13 ` Christoph Hellwig
2018-11-19 2:23 ` Ming Lei
2018-11-19 3:10 ` Jens Axboe
2018-11-19 3:35 ` Ming Lei
2018-11-15 8:52 ` [PATCH V10 02/19] block: introduce bio_for_each_bvec() Ming Lei
2018-11-15 18:28 ` Omar Sandoval
2018-11-16 13:30 ` Christoph Hellwig
2018-11-19 3:31 ` Ming Lei
2018-11-15 8:52 ` [PATCH V10 03/19] block: use bio_for_each_bvec() to compute multi-page bvec count Ming Lei
2018-11-15 20:20 ` Omar Sandoval
2018-11-15 21:05 ` Mike Snitzer
2018-11-15 22:18 ` Omar Sandoval
2018-11-16 9:19 ` Christoph Hellwig
2018-11-16 9:41 ` Gao Xiang
2018-11-16 16:04 ` Omar Sandoval
2018-11-19 7:50 ` Ming Lei
2018-11-15 8:52 ` [PATCH V10 04/19] block: use bio_for_each_bvec() to map sg Ming Lei
2018-11-15 22:33 ` Omar Sandoval
2018-11-16 13:33 ` Christoph Hellwig
2018-11-19 7:51 ` Ming Lei
2018-11-15 8:52 ` [PATCH V10 05/19] block: introduce bvec_last_segment() Ming Lei
2018-11-15 23:23 ` Omar Sandoval
2018-11-19 7:57 ` Ming Lei
2018-11-16 13:34 ` Christoph Hellwig
2018-11-15 8:52 ` [PATCH V10 06/19] fs/buffer.c: use bvec iterator to truncate the bio Ming Lei
2018-11-16 0:20 ` Omar Sandoval
2018-11-16 13:36 ` Christoph Hellwig
2018-11-15 8:52 ` [PATCH V10 07/19] btrfs: use bvec_last_segment to get bio's last page Ming Lei
2018-11-16 0:21 ` Omar Sandoval
2018-11-16 13:37 ` Christoph Hellwig
2018-11-19 8:09 ` Ming Lei
2018-11-15 8:52 ` [PATCH V10 08/19] btrfs: move bio_pages_all() to btrfs Ming Lei
2018-11-16 0:23 ` Omar Sandoval
2018-11-19 8:15 ` Ming Lei
2018-11-16 13:38 ` Christoph Hellwig
2018-11-19 8:19 ` Ming Lei
2018-11-19 8:24 ` Christoph Hellwig
2018-11-15 8:52 ` [PATCH V10 09/19] block: introduce bio_bvecs() Ming Lei
2018-11-16 0:26 ` Omar Sandoval
2018-11-16 13:45 ` Christoph Hellwig
2018-11-19 8:21 ` Ming Lei [this message]
2018-11-20 0:49 ` Sagi Grimberg
2018-11-20 16:16 ` Christoph Hellwig
2018-11-20 20:11 ` Sagi Grimberg
2018-11-21 0:59 ` Ming Lei
2018-11-21 3:20 ` Sagi Grimberg
2018-11-21 3:44 ` Ming Lei
2018-11-21 4:25 ` Sagi Grimberg
2018-11-21 4:42 ` Sagi Grimberg
2018-11-21 5:04 ` Ming Lei
2018-11-21 5:35 ` Sagi Grimberg
2018-11-21 8:46 ` Christoph Hellwig
2018-11-21 10:19 ` Ming Lei
2018-11-15 8:52 ` [PATCH V10 10/19] block: loop: pass multi-page bvec to iov_iter Ming Lei
2018-11-16 0:40 ` Omar Sandoval
2018-11-19 8:25 ` Ming Lei
2018-11-15 8:52 ` [PATCH V10 11/19] bcache: avoid to use bio_for_each_segment_all() in bch_bio_alloc_pages() Ming Lei
2018-11-16 0:44 ` Omar Sandoval
2018-11-19 8:27 ` Ming Lei
2018-11-16 13:46 ` Christoph Hellwig
2018-11-19 8:28 ` Ming Lei
2018-11-15 8:52 ` [PATCH V10 12/19] block: allow bio_for_each_segment_all() to iterate over multi-page bvec Ming Lei
2018-11-15 12:42 ` David Sterba
2018-11-19 8:29 ` Ming Lei
2018-11-16 1:22 ` Omar Sandoval
2018-11-19 8:32 ` Ming Lei
2018-11-15 8:53 ` [PATCH V10 13/19] iomap & xfs: only account for new added page Ming Lei
2018-11-16 1:46 ` Omar Sandoval
2018-11-19 8:35 ` Ming Lei
2018-11-16 13:49 ` Christoph Hellwig
2018-11-19 8:39 ` Ming Lei
2018-11-15 8:53 ` [PATCH V10 14/19] block: enable multipage bvecs Ming Lei
2018-11-16 1:56 ` Omar Sandoval
2018-11-19 8:45 ` Ming Lei
2018-11-16 13:53 ` Christoph Hellwig
2018-11-19 9:00 ` Ming Lei
2018-11-15 8:53 ` [PATCH V10 15/19] block: always define BIO_MAX_PAGES as 256 Ming Lei
2018-11-16 1:59 ` Omar Sandoval
2018-11-19 9:04 ` Ming Lei
2018-11-20 2:45 ` Huang, Ying
2018-11-16 13:53 ` Christoph Hellwig
2018-11-15 8:53 ` [PATCH V10 16/19] block: document usage of bio iterator helpers Ming Lei
2018-11-16 2:05 ` Omar Sandoval
2018-11-15 8:53 ` [PATCH V10 17/19] block: don't use bio->bi_vcnt to figure out segment number Ming Lei
2018-11-16 2:11 ` Omar Sandoval
2018-11-19 9:06 ` Ming Lei
2018-11-16 13:55 ` Christoph Hellwig
2018-11-15 8:53 ` [PATCH V10 18/19] block: kill QUEUE_FLAG_NO_SG_MERGE Ming Lei
2018-11-16 2:18 ` Omar Sandoval
2018-11-16 13:59 ` Christoph Hellwig
2018-11-16 16:40 ` Omar Sandoval
2018-11-19 9:17 ` Ming Lei
2018-11-16 13:58 ` Christoph Hellwig
2018-11-19 9:20 ` Ming Lei
2018-11-15 8:53 ` [PATCH V10 19/19] block: kill BLK_MQ_F_SG_MERGE Ming Lei
2018-11-16 13:59 ` Christoph Hellwig
2018-11-16 16:40 ` Omar Sandoval
2018-11-16 14:03 ` [PATCH V10 00/19] block: support multi-page bvec Christoph Hellwig
2018-11-17 2:42 ` Ming Lei
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