locking/spinlocks: Always evaluate the second argument of spin_lock_nested()

[mirror_ubuntu-bionic-kernel.git] / include / linux / spinlock.h

diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h
index 3f2867ff0ced55086615610aa6807f80af042b08..262ba4ef9a8ebacb24e7f7326a05bbcb2f666c69 100644 (file)
--- a/include/linux/spinlock.h
+++ b/include/linux/spinlock.h
@@ -197,7 +197,13 @@ static inline void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock)
                 _raw_spin_lock_nest_lock(lock, &(nest_lock)->dep_map); \
         } while (0)
 #else
-# define raw_spin_lock_nested(lock, subclass)          _raw_spin_lock(lock)
+/*
+ * Always evaluate the 'subclass' argument to avoid that the compiler
+ * warns about set-but-not-used variables when building with
+ * CONFIG_DEBUG_LOCK_ALLOC=n and with W=1.
+ */
+# define raw_spin_lock_nested(lock, subclass)          \
+       _raw_spin_lock(((void)(subclass), (lock)))
 # define raw_spin_lock_nest_lock(lock, nest_lock)      _raw_spin_lock(lock)
 #endif