[Trusty][PATCH 1/2] Revert "dm: fix AB-BA deadlock in __dm_destroy()"

[Luis Henriques]

BugLink: https://bugs.launchpad.net/bugs/1522766

This reverts commit 340f3e9970d6251a549d0c8cf90179b190f15def, which was
commit 2a708cff93f1845b9239bc7d6310aef54e716c6a upstream.

Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/md/dm.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 23c95ba85019..ad6cf066c992 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -2490,14 +2490,14 @@ static void __dm_destroy(struct mapped_device *md, bool wait)
 	 * do not race with internal suspend.
 	 */
 	mutex_lock(&md->suspend_lock);
-	map = dm_get_live_table(md, &srcu_idx);
 	if (!dm_suspended_md(md)) {
 		dm_table_presuspend_targets(map);
 		dm_table_postsuspend_targets(map);
 	}
+	mutex_unlock(&md->suspend_lock);
+
 	/* dm_put_live_table must be before msleep, otherwise deadlock is possible */
 	dm_put_live_table(md, srcu_idx);
-	mutex_unlock(&md->suspend_lock);
 
 	/*
 	 * Rare, but there may be I/O requests still going to complete,