locking/rwsem, xtensa: Drop superfluous arch specific implementation

Since "locking, rwsem: drop explicit memory barriers" the arch specific
code is basically same as the the generic one so we can drop the
superfluous code.

Suggested-by: Davidlohr Bueso <[e-mail]>
Signed-off-by: Michal Hocko <[e-mail]>
Acked-by: Max Filippov <[e-mail]>
Cc: Andrew Morton <[e-mail]>
Cc: Chris Zankel <[e-mail]>
Cc: David S. Miller <[e-mail]>
Cc: Linus Torvalds <[e-mail]>
Cc: Paul E. McKenney <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Signed-off-by: Davidlohr Bueso <[e-mail]>
Cc: Signed-off-by: Jason Low <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: Tony Luck <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Ingo Molnar <[e-mail]>

arch/xtensa/include/asm/Kbuild

···
 generic-y += percpu.h
 generic-y += preempt.h
 generic-y += resource.h
+generic-y += rwsem.h
 generic-y += sections.h
 generic-y += siginfo.h
 generic-y += statfs.h

arch/xtensa/include/asm/rwsem.h

···
-/*
- * include/asm-xtensa/rwsem.h
- *
- * This file is subject to the terms and conditions of the GNU General Public
- * License.  See the file "COPYING" in the main directory of this archive
- * for more details.
- *
- * Largely copied from include/asm-ppc/rwsem.h
- *
- * Copyright (C) 2001 - 2005 Tensilica Inc.
- */
-
-#ifndef _XTENSA_RWSEM_H
-#define _XTENSA_RWSEM_H
-
-#ifndef _LINUX_RWSEM_H
-#error "Please don't include <asm/rwsem.h> directly, use <linux/rwsem.h> instead."
-#endif
-
-#define RWSEM_UNLOCKED_VALUE		0x00000000
-#define RWSEM_ACTIVE_BIAS		0x00000001
-#define RWSEM_ACTIVE_MASK		0x0000ffff
-#define RWSEM_WAITING_BIAS		(-0x00010000)
-#define RWSEM_ACTIVE_READ_BIAS		RWSEM_ACTIVE_BIAS
-#define RWSEM_ACTIVE_WRITE_BIAS		(RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS)
-
-/*
- * lock for reading
- */
-static inline void __down_read(struct rw_semaphore *sem)
-{
-	if (atomic_add_return(1,(atomic_t *)(&sem->count)) <= 0)
-		rwsem_down_read_failed(sem);
-}
-
-static inline int __down_read_trylock(struct rw_semaphore *sem)
-{
-	int tmp;
-
-	while ((tmp = sem->count) >= 0) {
-		if (tmp == cmpxchg(&sem->count, tmp,
-				   tmp + RWSEM_ACTIVE_READ_BIAS)) {
-			return 1;
-		}
-	}
-	return 0;
-}
-
-/*
- * lock for writing
- */
-static inline void __down_write(struct rw_semaphore *sem)
-{
-	int tmp;
-
-	tmp = atomic_add_return(RWSEM_ACTIVE_WRITE_BIAS,
-				(atomic_t *)(&sem->count));
-	if (tmp != RWSEM_ACTIVE_WRITE_BIAS)
-		rwsem_down_write_failed(sem);
-}
-
-static inline int __down_write_trylock(struct rw_semaphore *sem)
-{
-	int tmp;
-
-	tmp = cmpxchg(&sem->count, RWSEM_UNLOCKED_VALUE,
-		      RWSEM_ACTIVE_WRITE_BIAS);
-	return tmp == RWSEM_UNLOCKED_VALUE;
-}
-
-/*
- * unlock after reading
- */
-static inline void __up_read(struct rw_semaphore *sem)
-{
-	int tmp;
-
-	tmp = atomic_sub_return(1,(atomic_t *)(&sem->count));
-	if (tmp < -1 && (tmp & RWSEM_ACTIVE_MASK) == 0)
-		rwsem_wake(sem);
-}
-
-/*
- * unlock after writing
- */
-static inline void __up_write(struct rw_semaphore *sem)
-{
-	if (atomic_sub_return(RWSEM_ACTIVE_WRITE_BIAS,
-			      (atomic_t *)(&sem->count)) < 0)
-		rwsem_wake(sem);
-}
-
-/*
- * implement atomic add functionality
- */
-static inline void rwsem_atomic_add(int delta, struct rw_semaphore *sem)
-{
-	atomic_add(delta, (atomic_t *)(&sem->count));
-}
-
-/*
- * downgrade write lock to read lock
- */
-static inline void __downgrade_write(struct rw_semaphore *sem)
-{
-	int tmp;
-
-	tmp = atomic_add_return(-RWSEM_WAITING_BIAS, (atomic_t *)(&sem->count));
-	if (tmp < 0)
-		rwsem_downgrade_wake(sem);
-}
-
-/*
- * implement exchange and add functionality
- */
-static inline int rwsem_atomic_update(int delta, struct rw_semaphore *sem)
-{
-	return atomic_add_return(delta, (atomic_t *)(&sem->count));
-}
-
-#endif	/* _XTENSA_RWSEM_H */