[PATCH v2 09/11] dm-raid: add a new helper prepare_suspend() in md_personality

[Yu Kuai <yukuai3@huawei.com>]

There are no functional changes for now, prepare to fix a deadlock for
dm-raid456.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
---
 drivers/md/dm-raid.c | 10 +++++++---
 drivers/md/md.h      |  1 +
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index f1637cf88559..ede2e4574ee5 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -3806,10 +3806,14 @@ static void raid_io_hints(struct dm_target *ti, struct queue_limits *limits)
 static void raid_presuspend(struct dm_target *ti)
 {
 	struct raid_set *rs = ti->private;
+	struct mddev *mddev = &rs->md;
 
-	mddev_lock_nointr(&rs->md);
-	md_frozen_sync_thread(&rs->md);
-	mddev_unlock(&rs->md);
+	mddev_lock_nointr(mddev);
+	md_frozen_sync_thread(mddev);
+	mddev_unlock(mddev);
+
+	if (mddev->pers && mddev->pers->prepare_suspend)
+		mddev->pers->prepare_suspend(mddev);
 }
 
 static void raid_presuspend_undo(struct dm_target *ti)
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 437ab70ce79b..29b476ff3b9f 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -617,6 +617,7 @@ struct md_personality
 	int (*start_reshape) (struct mddev *mddev);
 	void (*finish_reshape) (struct mddev *mddev);
 	void (*update_reshape_pos) (struct mddev *mddev);
+	void (*prepare_suspend) (struct mddev *mddev);
 	/* quiesce suspends or resumes internal processing.
 	 * 1 - stop new actions and wait for action io to complete
 	 * 0 - return to normal behaviour
-- 
2.39.2