From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A6C4811705 for ; Mon, 11 Sep 2023 14:42:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2695CC433CA; Mon, 11 Sep 2023 14:42:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1694443327; bh=XPBo8QNI4ToO1XSzr7YPhYNGL74sJGP6MhGG5CbbhXE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=t+peE8Du74FtwVMiJvBBCl4xNYzFkP8G6pryuQ++JYOzG9xzLYMZR2dRLMFRyNF8f Pvo5TN7DLNalSFzZNd2SnsqkJUv649wvU1zgjNyDOwZTh/540Y3iuwI4w9j2K0+OYk m9O1FFPyXR0ZuWVtPOII8P/2Ytrd+fUFfHHsfdfw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Li Nan , Song Liu , Sasha Levin Subject: [PATCH 6.4 339/737] md/raid10: factor out dereference_rdev_and_rrdev() Date: Mon, 11 Sep 2023 15:43:18 +0200 Message-ID: <20230911134700.000643074@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230911134650.286315610@linuxfoundation.org> References: <20230911134650.286315610@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Li Nan [ Upstream commit b99f8fd2d91eb734f13098aa1cf337edaca454b7 ] Factor out a helper to get 'rdev' and 'replacement' from config->mirrors. Just to make code cleaner and prepare to fix the bug of io loss while 'replacement' replace 'rdev'. There is no functional change. Signed-off-by: Li Nan Link: https://lore.kernel.org/r/20230701080529.2684932-3-linan666@huaweicloud.com Signed-off-by: Song Liu Stable-dep-of: 673643490b9a ("md/raid10: use dereference_rdev_and_rrdev() to get devices") Signed-off-by: Sasha Levin --- drivers/md/raid10.c | 29 ++++++++++++++++++++--------- 1 file changed, 20 insertions(+), 9 deletions(-) diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index ee75b058438f3..f47fd50651c45 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -1321,6 +1321,25 @@ static void raid10_write_one_disk(struct mddev *mddev, struct r10bio *r10_bio, } } +static struct md_rdev *dereference_rdev_and_rrdev(struct raid10_info *mirror, + struct md_rdev **prrdev) +{ + struct md_rdev *rdev, *rrdev; + + rrdev = rcu_dereference(mirror->replacement); + /* + * Read replacement first to prevent reading both rdev and + * replacement as NULL during replacement replace rdev. + */ + smp_mb(); + rdev = rcu_dereference(mirror->rdev); + if (rdev == rrdev) + rrdev = NULL; + + *prrdev = rrdev; + return rdev; +} + static void wait_blocked_dev(struct mddev *mddev, struct r10bio *r10_bio) { int i; @@ -1464,15 +1483,7 @@ static void raid10_write_request(struct mddev *mddev, struct bio *bio, int d = r10_bio->devs[i].devnum; struct md_rdev *rdev, *rrdev; - rrdev = rcu_dereference(conf->mirrors[d].replacement); - /* - * Read replacement first to prevent reading both rdev and - * replacement as NULL during replacement replace rdev. - */ - smp_mb(); - rdev = rcu_dereference(conf->mirrors[d].rdev); - if (rdev == rrdev) - rrdev = NULL; + rdev = dereference_rdev_and_rrdev(&conf->mirrors[d], &rrdev); if (rdev && (test_bit(Faulty, &rdev->flags))) rdev = NULL; if (rrdev && (test_bit(Faulty, &rrdev->flags))) -- 2.40.1