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 2bca44b..bfe88c4 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -359,7 +359,9 @@
#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)