[PATCH 2/2] sh, rwsem: drop superfluous arch specific implementation

[Michal Hocko]

From: Michal Hocko <mhocko@xxxxxxxx>

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 <dave@xxxxxxxxxxxx>
Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
---
 arch/sh/include/asm/Kbuild  |   1 +
 arch/sh/include/asm/rwsem.h | 130 --------------------------------------------
 2 files changed, 1 insertion(+), 130 deletions(-)
 delete mode 100644 arch/sh/include/asm/rwsem.h

diff --git a/arch/sh/include/asm/Kbuild b/arch/sh/include/asm/Kbuild
index aac452b26aa8..6d866c7a9b74 100644
--- a/arch/sh/include/asm/Kbuild
+++ b/arch/sh/include/asm/Kbuild
@@ -25,6 +25,7 @@ generic-y += percpu.h
 generic-y += poll.h
 generic-y += preempt.h
 generic-y += resource.h
+generic-y += rwsem.h
 generic-y += sembuf.h
 generic-y += serial.h
 generic-y += shmbuf.h
diff --git a/arch/sh/include/asm/rwsem.h b/arch/sh/include/asm/rwsem.h
deleted file mode 100644
index 8a457b83d2a5..000000000000
--- a/arch/sh/include/asm/rwsem.h
+++ /dev/null
@@ -1,130 +0,0 @@
-/*
- * include/asm-sh/rwsem.h: R/W semaphores for SH using the stuff
- * in lib/rwsem.c.
- */
-
-#ifndef _ASM_SH_RWSEM_H
-#define _ASM_SH_RWSEM_H
-
-#ifndef _LINUX_RWSEM_H
-#error "please don't include asm/rwsem.h directly, use linux/rwsem.h instead"
-#endif
-
-#ifdef __KERNEL__
-
-#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_inc_return((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_killable(struct rw_semaphore *sem)
-{
-	int tmp;
-
-	tmp = atomic_add_return(RWSEM_ACTIVE_WRITE_BIAS,
-				(atomic_t *)(&sem->count));
-	if (tmp != RWSEM_ACTIVE_WRITE_BIAS)
-		if (IS_ERR(rwsem_down_write_failed_killable(sem)))
-			return -EINTR;
-
-	return 0;
-}
-
-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_dec_return((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 /* __KERNEL__ */
-#endif /* _ASM_SH_RWSEM_H */
-- 
2.8.0.rc3