[PATCH] md: protect read mddev->recovery in md_sync_action()

["Chen Cheng" <chencheng@fnnas.com>]

From: Chen Cheng <chencheng@fnnas.com>

md_sync_action() read mddev->recovery in lockless path, use READ_ONCE()
instead of u64 plain read.

Fixes: e792a4c2156a3 ("md: add new helpers for sync_action")

Signed-off-by: Chen Cheng <chencheng@fnnas.com>
---
 drivers/md/md.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index c5c50640b684..f4415c1a79d9 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -5074,11 +5074,11 @@ static enum sync_action md_get_active_sync_action(struct mddev *mddev)
 	return is_recover ? ACTION_RECOVER : ACTION_IDLE;
 }
 
 enum sync_action md_sync_action(struct mddev *mddev)
 {
-	unsigned long recovery = mddev->recovery;
+	unsigned long recovery = READ_ONCE(mddev->recovery);
 	enum sync_action active_action;
 
 	/*
 	 * frozen has the highest priority, means running sync_thread will be
 	 * stopped immediately, and no new sync_thread can start.
-- 
2.54.0