[PATCH V10 06/19] fs/buffer.c: use bvec iterator to truncate the bio

Ming Lei
2018-11-15T08:55:00Z

Once multi-page bvec is enabled, the last bvec may include more than one
page, this patch use bvec_last_segment() to truncate the bio.

Cc: Dave Chinner <dchinner@redhat.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: dm-devel@redhat.com
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Cc: Shaohua Li <shli@kernel.org>
Cc: linux-raid@vger.kernel.org
Cc: linux-erofs@lists.ozlabs.org
Cc: David Sterba <dsterba@suse.com>
Cc: linux-btrfs@vger.kernel.org
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: linux-xfs@vger.kernel.org
Cc: Gao Xiang <gaoxiang25@huawei.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: linux-ext4@vger.kernel.org
Cc: Coly Li <colyli@suse.de>
Cc: linux-bcache@vger.kernel.org
Cc: Boaz Harrosh <ooo@electrozaur.com>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: cluster-devel@redhat.com
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
fs/buffer.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/buffer.c b/fs/buffer.c
index 1286c2b95498..fa37ad52e962 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -3032,7 +3032,10 @@ void guard_bio_eod(int op, struct bio *bio)

/* ..and clear the end of the buffer for reads */
if (op == REQ_OP_READ) {
- zero_user(bvec->bv_page, bvec->bv_offset + bvec->bv_len,
+ struct bio_vec bv;
+
+ bvec_last_segment(bvec, &bv);
+ zero_user(bv.bv_page, bv.bv_offset + bv.bv_len,
truncated_bytes);
}
}
--
2.9.5