linux-kernel - [PATCH -next 7/8] md: use new helper to stop sync_thread in __md_stop

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Date:   Sat, 11 Nov 2023 01:28:33 +0800
From:   Yu Kuai <yukuai1@...weicloud.com>
To:     song@...nel.org, xni@...hat.com, yukuai3@...wei.com, neilb@...e.de
Cc:     linux-kernel@...r.kernel.org, linux-raid@...r.kernel.org,
        yukuai1@...weicloud.com, yi.zhang@...wei.com, yangerkun@...wei.com
Subject: [PATCH -next 7/8] md: use new helper to stop sync_thread in __md_stop_writes()

From: Yu Kuai <yukuai3@...wei.com>

md_reap_sync_thread() should only be called when md_do_sync() is done,
for example, holding 'reconfig_mutex' to wait for md_do_sync() to be
done can deadlock(see details in commit 130443d60b1b ("md: refactor
idle/frozen_sync_thread() to fix deadlock")). Hence use new helper to
stop sync_thread.

Signed-off-by: Yu Kuai <yukuai3@...wei.com>
Signed-off-by: Yu Kuai <yukuai1@...weicloud.com>
---
 drivers/md/md.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 7252fae0c989..35f3dd7db369 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -6325,12 +6325,11 @@ static void md_clean(struct mddev *mddev)
 
 static void __md_stop_writes(struct mddev *mddev)
 {
-	set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
-	if (work_pending(&mddev->sync_work))
-		flush_workqueue(md_misc_wq);
-	if (mddev->sync_thread) {
-		set_bit(MD_RECOVERY_INTR, &mddev->recovery);
-		md_reap_sync_thread(mddev);
+	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) {
+		stop_sync_thread(mddev, true, false);
+		mddev_lock_nointr(mddev);
+	} else {
+		set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
 	}
 
 	del_timer_sync(&mddev->safemode_timer);
-- 
2.39.2