[PATCH v2 2/4] maple_tree: Relax lockdep checks for on-stack trees

[Liam R. Howlett]

To support early release of the maple tree locks, do not lockdep check
the lock if it is set to NULL.  This is intended for the special case
on-stack use of tracking entries and not for general use.

Cc: Linus Torvalds <torvalds at linux-foundation.org>
Signed-off-by: Liam R. Howlett <Liam.Howlett at oracle.com>
---
 include/linux/maple_tree.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/include/linux/maple_tree.h b/include/linux/maple_tree.h
index 7769270b85e8..6618c1512886 100644
--- a/include/linux/maple_tree.h
+++ b/include/linux/maple_tree.h
@@ -182,7 +182,9 @@ enum maple_type {
 
 #ifdef CONFIG_LOCKDEP
 typedef struct lockdep_map *lockdep_map_p;
-#define mt_lock_is_held(mt)	lock_is_held(mt->ma_external_lock)
+#define mt_lock_is_held(mt)                                             \
+	(!(mt)->ma_external_lock || lock_is_held((mt)->ma_external_lock))
+
 #define mt_set_external_lock(mt, lock)					\
 	(mt)->ma_external_lock = &(lock)->dep_map
 #else
-- 
2.39.2