To make spinlock debugging work with -funsigned-char the i386 version
of spin_is_locked() needs to cast to signed char explicitly instead of
just char. XFS needed -funsigned-char (and currently still has it),
but it doesn't evert hurt.
* We make no fairness assumptions. They have a cost.
*/
-#define spin_is_locked(x) (*(volatile char *)(&(x)->lock) <= 0)
+#define spin_is_locked(x) (*(volatile signed char *)(&(x)->lock) <= 0)
#define spin_unlock_wait(x) do { barrier(); } while(spin_is_locked(x))
#define spin_lock_string \