commit b1ae345d971664f70cfdc293029c40ccfb093591
Author: Johannes Berg <johannes.berg@intel.com>;
Date:   Thu Feb 21 16:42:47 2013 -0800

    lockdep: make lockdep_assert_held() not have a return value
    
    I recently made the mistake of writing:
    
      foo = lockdep_dereference_protected(..., lockdep_assert_held(...));
    
    which is clearly bogus.  If lockdep is disabled in the config this would
    cause a compile failure, if it is enabled then it compiles and causes a
    puzzling warning about dereferencing without the correct protection.
    
    Wrap the macro in "do { ...  } while (0)" to also fail compile for this
    when lockdep is enabled.
    
    Signed-off-by: Johannes Berg <johannes.berg@intel.com>;
    Cc: Peter Zijlstra <peterz@infradead.org>;
    Cc: Ingo Molnar <mingo@redhat.com>;
    Signed-off-by: Andrew Morton <akpm@linux-foundation.org>;
    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>;

diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 2bca44b0893c..bfe88c4aa251 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -359,7 +359,9 @@ extern void lockdep_trace_alloc(gfp_t mask);
 
 #define lockdep_depth(tsk)	(debug_locks ? (tsk)->lockdep_depth : 0)
 
-#define lockdep_assert_held(l)	WARN_ON(debug_locks && !lockdep_is_held(l))
+#define lockdep_assert_held(l)	do {				\
+		WARN_ON(debug_locks && !lockdep_is_held(l));	\
+	} while (0)
 
 #define lockdep_recursing(tsk)	((tsk)->lockdep_recursion)