locking/arch: Remove dummy arch_{read,spin,write}_relax() implementations

arch_{read,spin,write}_relax() are defined as cpu_relax() by the core
code, so architectures that can't do better (i.e. most of them) don't
need to bother with the dummy definitions.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: paulmck@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/1507055129-12300-3-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/arc/include/asm/spinlock.h

@@ -413,8 +413,4 @@ static inline void arch_write_unlock(arch_rwlock_t *rw)
 #define arch_read_lock_flags(lock, flags)	arch_read_lock(lock)
 #define arch_write_lock_flags(lock, flags)	arch_write_lock(lock)
 
-#define arch_spin_relax(lock)	cpu_relax()
-#define arch_read_relax(lock)	cpu_relax()
-#define arch_write_relax(lock)	cpu_relax()
-
 #endif /* __ASM_SPINLOCK_H */

arch/arm/include/asm/spinlock.h

@@ -273,8 +273,4 @@ static inline int arch_read_trylock(arch_rwlock_t *rw)
 #define arch_read_lock_flags(lock, flags) arch_read_lock(lock)
 #define arch_write_lock_flags(lock, flags) arch_write_lock(lock)
 
-#define arch_spin_relax(lock)	cpu_relax()
-#define arch_read_relax(lock)	cpu_relax()
-#define arch_write_relax(lock)	cpu_relax()
-
 #endif /* __ASM_SPINLOCK_H */

arch/arm64/include/asm/spinlock.h

@@ -306,10 +306,6 @@ static inline int arch_read_trylock(arch_rwlock_t *rw)
 #define arch_read_lock_flags(lock, flags) arch_read_lock(lock)
 #define arch_write_lock_flags(lock, flags) arch_write_lock(lock)
 
-#define arch_spin_relax(lock)	cpu_relax()
-#define arch_read_relax(lock)	cpu_relax()
-#define arch_write_relax(lock)	cpu_relax()
-
 /* See include/linux/spinlock.h */
 #define smp_mb__after_spinlock()	smp_mb()
 

arch/blackfin/include/asm/spinlock.h

@@ -82,10 +82,6 @@ static inline void arch_write_unlock(arch_rwlock_t *rw)
 	__raw_write_unlock_asm(&rw->lock);
 }
 
-#define arch_spin_relax(lock)  	cpu_relax()
-#define arch_read_relax(lock)	cpu_relax()
-#define arch_write_relax(lock)	cpu_relax()
-
 #endif
 
 #endif /*  !__BFIN_SPINLOCK_H */

arch/ia64/include/asm/spinlock.h

@@ -269,8 +269,4 @@ static inline int arch_read_trylock(arch_rwlock_t *x)
 	return (u32)ia64_cmpxchg4_acq((__u32 *)(x), new.word, old.word) == old.word;
 }
 
-#define arch_spin_relax(lock)	cpu_relax()
-#define arch_read_relax(lock)	cpu_relax()
-#define arch_write_relax(lock)	cpu_relax()
-
 #endif /*  _ASM_IA64_SPINLOCK_H */

arch/m32r/include/asm/spinlock.h

@@ -308,8 +308,4 @@ static inline int arch_write_trylock(arch_rwlock_t *lock)
 #define arch_read_lock_flags(lock, flags) arch_read_lock(lock)
 #define arch_write_lock_flags(lock, flags) arch_write_lock(lock)
 
-#define arch_spin_relax(lock)	cpu_relax()
-#define arch_read_relax(lock)	cpu_relax()
-#define arch_write_relax(lock)	cpu_relax()
-
 #endif	/* _ASM_M32R_SPINLOCK_H */

arch/metag/include/asm/spinlock.h

@@ -20,8 +20,4 @@
 #define	arch_read_lock_flags(lock, flags) arch_read_lock(lock)
 #define	arch_write_lock_flags(lock, flags) arch_write_lock(lock)
 
-#define arch_spin_relax(lock)	cpu_relax()
-#define arch_read_relax(lock)	cpu_relax()
-#define arch_write_relax(lock)	cpu_relax()
-
 #endif /* __ASM_SPINLOCK_H */

arch/metag/include/asm/spinlock_lnkget.h

@@ -212,8 +212,4 @@ static inline int arch_read_trylock(arch_rwlock_t *rw)
 #define	arch_read_lock_flags(lock, flags) arch_read_lock(lock)
 #define	arch_write_lock_flags(lock, flags) arch_write_lock(lock)
 
-#define arch_spin_relax(lock)	cpu_relax()
-#define arch_read_relax(lock)	cpu_relax()
-#define arch_write_relax(lock)	cpu_relax()
-
 #endif /* __ASM_SPINLOCK_LNKGET_H */

arch/mips/include/asm/spinlock.h

@@ -16,8 +16,4 @@
 #define arch_read_lock_flags(lock, flags) arch_read_lock(lock)
 #define arch_write_lock_flags(lock, flags) arch_write_lock(lock)
 
-#define arch_spin_relax(lock)	cpu_relax()
-#define arch_read_relax(lock)	cpu_relax()
-#define arch_write_relax(lock)	cpu_relax()
-
 #endif /* _ASM_SPINLOCK_H */

arch/s390/include/asm/spinlock.h

@@ -45,6 +45,7 @@ static inline void arch_spin_relax(arch_spinlock_t *lock)
 {
 	arch_lock_relax(lock->lock);
 }
+#define arch_spin_relax		arch_spin_relax
 
 static inline u32 arch_spin_lockval(int cpu)
 {
@@ -256,10 +257,12 @@ static inline void arch_read_relax(arch_rwlock_t *rw)
 {
 	arch_lock_relax(rw->owner);
 }
+#define arch_read_relax		arch_read_relax
 
 static inline void arch_write_relax(arch_rwlock_t *rw)
 {
 	arch_lock_relax(rw->owner);
 }
+#define arch_write_relax	arch_write_relax
 
 #endif /* __ASM_SPINLOCK_H */

arch/sh/include/asm/spinlock-cas.h

@@ -93,8 +93,4 @@ static inline int arch_write_trylock(arch_rwlock_t *rw)
 #define arch_read_lock_flags(lock, flags) arch_read_lock(lock)
 #define arch_write_lock_flags(lock, flags) arch_write_lock(lock)
 
-#define arch_spin_relax(lock)	cpu_relax()
-#define arch_read_relax(lock)	cpu_relax()
-#define arch_write_relax(lock)	cpu_relax()
-
 #endif /* __ASM_SH_SPINLOCK_CAS_H */

arch/sh/include/asm/spinlock-llsc.h

@@ -200,8 +200,4 @@ static inline int arch_write_trylock(arch_rwlock_t *rw)
 #define arch_read_lock_flags(lock, flags) arch_read_lock(lock)
 #define arch_write_lock_flags(lock, flags) arch_write_lock(lock)
 
-#define arch_spin_relax(lock)	cpu_relax()
-#define arch_read_relax(lock)	cpu_relax()
-#define arch_write_relax(lock)	cpu_relax()
-
 #endif /* __ASM_SH_SPINLOCK_LLSC_H */

arch/sparc/include/asm/spinlock_32.h

@@ -186,10 +186,6 @@ static inline int __arch_read_trylock(arch_rwlock_t *rw)
 #define arch_read_lock_flags(rw, flags)   arch_read_lock(rw)
 #define arch_write_lock_flags(rw, flags)  arch_write_lock(rw)
 
-#define arch_spin_relax(lock)	cpu_relax()
-#define arch_read_relax(lock)	cpu_relax()
-#define arch_write_relax(lock)	cpu_relax()
-
 #endif /* !(__ASSEMBLY__) */
 
 #endif /* __SPARC_SPINLOCK_H */

arch/sparc/include/asm/spinlock_64.h

@@ -16,10 +16,6 @@
 #define arch_read_lock_flags(p, f) arch_read_lock(p)
 #define arch_write_lock_flags(p, f) arch_write_lock(p)
 
-#define arch_spin_relax(lock)	cpu_relax()
-#define arch_read_relax(lock)	cpu_relax()
-#define arch_write_relax(lock)	cpu_relax()
-
 #endif /* !(__ASSEMBLY__) */
 
 #endif /* !(__SPARC64_SPINLOCK_H) */

arch/x86/include/asm/spinlock.h

@@ -44,8 +44,4 @@
 #define arch_read_lock_flags(lock, flags) arch_read_lock(lock)
 #define arch_write_lock_flags(lock, flags) arch_write_lock(lock)
 
-#define arch_spin_relax(lock)	cpu_relax()
-#define arch_read_relax(lock)	cpu_relax()
-#define arch_write_relax(lock)	cpu_relax()
-
 #endif /* _ASM_X86_SPINLOCK_H */