[PATCH v5 2/9] locking/lockdep: Provide empty lockdep_map structure for !CONFIG_LOCKDEP

[Byungchul Park <byungchul.park@xxxxxxx>]

By this patch, the lockdep_map structure takes no space if lockdep is
disabled, making a debug facility's impact on unreleated kernel less.

Thanks to this, we don't need #ifdef to sparate code due to the
lockdep_map structure.

Signed-off-by: Byungchul Park <byungchul.park@xxxxxxx>
---
 include/linux/lockdep.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index bfa8e0b..b6662d0 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -527,6 +527,11 @@ static inline void lockdep_on(void)
  */
 struct lock_class_key { };
 
+/*
+ * The lockdep_map takes no space if lockdep is disabled:
+ */
+struct lockdep_map { };
+
 #define lockdep_depth(tsk)	(0)
 
 #define lockdep_is_held_type(l, r)		(1)
-- 
1.9.1