From: Jakub Kicinski <kuba@xxxxxxxxxx>
We run into a unused variable warning in bridge code when variable is
only used inside the condition of rcu_dereference_protected().
#define mlock_dereference(X, br) \
rcu_dereference_protected(X, lockdep_is_held(&br->multicast_lock))
Since on builds with CONFIG_PROVE_RCU=n rcu_dereference_protected()
compiles to nothing the compiler doesn't see the variable use.
This commit therefore prevents this warning by adding the condition as
dead code.
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
--
CC: paulmck@xxxxxxxxxx
CC: josh@xxxxxxxxxxxxxxxx
CC: rostedt@xxxxxxxxxxx
CC: mathieu.desnoyers@xxxxxxxxxxxx
CC: joel@xxxxxxxxxxxxxxxxx
CC: jiangshanlai@xxxxxxxxx
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
---
include/linux/rcupdate.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index f9533bb..de08264 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -328,7 +328,7 @@ static inline void rcu_preempt_sleep_check(void) { }
#else /* #ifdef CONFIG_PROVE_RCU */
-#define RCU_LOCKDEP_WARN(c, s) do { } while (0)
+#define RCU_LOCKDEP_WARN(c, s) do { } while (0 && (c))
#define rcu_sleep_check() do { } while (0)
#endif /* #else #ifdef CONFIG_PROVE_RCU */
--
2.9.5
