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From:   Ming Lei <ming.lei@redhat.com>
To:     Jens Axboe <axboe@fb.com>, Christoph Hellwig <hch@infradead.org>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Kent Overstreet <kent.overstreet@gmail.com>
Cc:     David Sterba <dsterba@suse.cz>, Huang Ying <ying.huang@intel.com>,
        linux-kernel@vger.kernel.org, linux-block@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
        Theodore Ts'o <tytso@mit.edu>,
        "Darrick J . Wong" <darrick.wong@oracle.com>,
        Coly Li <colyli@suse.de>, Filipe Manana <fdmanana@gmail.com>,
        Randy Dunlap <rdunlap@infradead.org>,
        Ming Lei <ming.lei@redhat.com>
Subject: [PATCH V6 16/30] dm: clone bio via bio_clone_chunk_bioset
Date:   Sat,  9 Jun 2018 20:30:00 +0800
Message-Id: <20180609123014.8861-17-ming.lei@redhat.com>
In-Reply-To: <20180609123014.8861-1-ming.lei@redhat.com>
References: <20180609123014.8861-1-ming.lei@redhat.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

The incoming bio will become very big after multipage bvec is enabled,
so we can't clone bio page by page.

This patch uses the introduced bio_clone_chunk_bioset(), so the incoming
bio can be cloned successfully. This way is safe because device mapping
won't modify the bio vector on the cloned multipage bio.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 drivers/md/dm.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 98dff36b89a3..13ca3574d972 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1582,8 +1582,8 @@ static blk_qc_t __split_and_process_bio(struct mapped_device *md,
 				 * the usage of io->orig_bio in dm_remap_zone_report()
 				 * won't be affected by this reassignment.
 				 */
-				struct bio *b = bio_clone_bioset(bio, GFP_NOIO,
-								 &md->queue->bio_split);
+				struct bio *b = bio_clone_chunk_bioset(bio, GFP_NOIO,
+								       &md->queue->bio_split);
 				ci.io->orig_bio = b;
 				bio_advance(bio, (bio_sectors(bio) - ci.sector_count) << 9);
 				bio_chain(b, bio);
-- 
2.9.5