x86: spinlocks: define dummy __raw_spin_is_contended

Architectures other than mips and x86 are not using ticket spinlocks.
Therefore, the contention on the lock is meaningless, since there is
nobody known to be waiting on it (arguably /fairly/ unfair locks).

Dummy it out to return 0 on other architectures.

Signed-off-by: Kyle McMartin <[e-mail]>
Acked-by: Ralf Baechle <[e-mail]>
Acked-by: Ingo Molnar <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

arch/mips/include/asm/spinlock.h

···
 
 	return (((counters >> 14) - counters) & 0x1fff) > 1;
 }
+#define __raw_spin_is_contended	__raw_spin_is_contended
 
 static inline void __raw_spin_lock(raw_spinlock_t *lock)
 {

arch/x86/include/asm/paravirt.h

···
 {
 	return PVOP_CALL1(int, pv_lock_ops.spin_is_contended, lock);
 }
+#define __raw_spin_is_contended	__raw_spin_is_contended
 
 static __always_inline void __raw_spin_lock(struct raw_spinlock *lock)
 {

arch/x86/include/asm/spinlock.h

···
 {
 	return __ticket_spin_is_contended(lock);
 }
+#define __raw_spin_is_contended	__raw_spin_is_contended
 
 static __always_inline void __raw_spin_lock(raw_spinlock_t *lock)
 {

include/linux/spinlock.h

···
 #ifdef CONFIG_GENERIC_LOCKBREAK
 #define spin_is_contended(lock) ((lock)->break_lock)
 #else
+
+#ifdef __raw_spin_is_contended
 #define spin_is_contended(lock)	__raw_spin_is_contended(&(lock)->raw_lock)
+#else
+#define spin_is_contended(lock)	(((void)(lock), 0))
+#endif /*__raw_spin_is_contended*/
 #endif
 
 /**