lockdep: lock_set_subclass - reset a held lock's subclass

this can be used to reset a held lock's subclass, for arbitrary-depth
iterated data structures such as trees or lists which have per-node
locks.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 1bfdc30bb0af..f270ce1582ff 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -300,6 +300,9 @@ extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
 extern void lock_release(struct lockdep_map *lock, int nested,
                          unsigned long ip);
 
+extern void lock_set_subclass(struct lockdep_map *lock, unsigned int subclass,
+                              unsigned long ip);
+
 # define INIT_LOCKDEP                           .lockdep_recursion = 0,
 
 #define lockdep_depth(tsk)      (debug_locks ? (tsk)->lockdep_depth : 0)
@@ -316,6 +319,7 @@ static inline void lockdep_on(void)
 
 # define lock_acquire(l, s, t, r, c, i)         do { } while (0)
 # define lock_release(l, n, i)                  do { } while (0)
+# define lock_set_subclass(l, s, i)             do { } while (0)
 # define lockdep_init()                         do { } while (0)
 # define lockdep_info()                         do { } while (0)
 # define lockdep_init_map(lock, name, key, sub) do { (void)(key); } while (0)