From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from userp1040.oracle.com ([156.151.31.81]:17011 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752178AbcESEUo (ORCPT ); Thu, 19 May 2016 00:20:44 -0400 From: Sasha Levin To: stable@vger.kernel.org, stable-commits@vger.kernel.org Cc: Shaohua Li , Ming Lei , Neil Brown , Sasha Levin Subject: [added to the 4.1 stable tree] MD: make bio mergeable Date: Thu, 19 May 2016 00:19:13 -0400 Message-Id: <1463631606-32540-14-git-send-email-sasha.levin@oracle.com> In-Reply-To: <1463631606-32540-1-git-send-email-sasha.levin@oracle.com> References: <1463631606-32540-1-git-send-email-sasha.levin@oracle.com> Sender: stable-owner@vger.kernel.org List-ID: From: Shaohua Li This patch has been added to the 4.1 stable tree. If you have any objections, please let us know. =============== [ Upstream commit 9c573de3283af007ea11c17bde1e4568d9417328 ] blk_queue_split marks bio unmergeable, which makes sense for normal bio. But if dispatching the bio to underlayer disk, the blk_queue_split checks are invalid, hence it's possible the bio becomes mergeable. In the reported bug, this bug causes trim against raid0 performance slash https://bugzilla.kernel.org/show_bug.cgi?id=117051 Reported-and-tested-by: Park Ju Hyung Fixes: 6ac45aeb6bca(block: avoid to merge splitted bio) Cc: stable@vger.kernel.org (v4.3+) Cc: Ming Lei Cc: Neil Brown Reviewed-by: Jens Axboe Signed-off-by: Shaohua Li Signed-off-by: Sasha Levin --- drivers/md/md.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/md/md.c b/drivers/md/md.c index 78c1f77..72dc91d 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -289,6 +289,8 @@ static void md_make_request(struct request_queue *q, struct bio *bio) * go away inside make_request */ sectors = bio_sectors(bio); + /* bio could be mergeable after passing to underlayer */ + bio->bi_rw &= ~REQ_NOMERGE; mddev->pers->make_request(mddev, bio); cpu = part_stat_lock(); -- 2.5.0