lockdep: Clear whole lockdep_map on initialization
Tejun Heo [Thu, 14 Jul 2011 13:19:09 +0000 (15:19 +0200)]
lockdep_init_map() only initializes parts of lockdep_map and triggers
kmemcheck warning when it is copied as a whole.  There isn't anything
to be gained by clearing selectively.  memset() the whole structure
and remove loop for ->class_cache[] clearing.

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=35532

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-and-tested-by: Christian Casteyde <casteyde.christian@free.fr>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=35532
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110714131909.GJ3455@htj.dyndns.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/lockdep.c

index 5903586..8c24294 100644 (file)
@@ -2874,10 +2874,7 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this,
 void lockdep_init_map(struct lockdep_map *lock, const char *name,
                      struct lock_class_key *key, int subclass)
 {
-       int i;
-
-       for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++)
-               lock->class_cache[i] = NULL;
+       memset(lock, 0, sizeof(*lock));
 
 #ifdef CONFIG_LOCK_STAT
        lock->cpu = raw_smp_processor_id();