Generic semaphore implementation

Semaphores are no longer performance-critical, so a generic C
implementation is better for maintainability, debuggability and
extensibility.  Thanks to Peter Zijlstra for fixing the lockdep
warning.  Thanks to Harvey Harrison for pointing out that the
unlikely() was unnecessary.

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 1 insertions, 187 deletions

diff --git a/include/asm-blackfin/semaphore-helper.h b/include/asm-blackfin/semaphore-helper.h
deleted file mode 100644
index 9082b0dc3eb5..000000000000
--- a/include/asm-blackfin/semaphore-helper.h
+++ /dev/null
@@ -1,82 +0,0 @@
-/* Based on M68K version,	Lineo Inc.	May 2001 */
-
-#ifndef _BFIN_SEMAPHORE_HELPER_H
-#define _BFIN_SEMAPHORE_HELPER_H
-
-/*
- * SMP- and interrupt-safe semaphores helper functions.
- *
- * (C) Copyright 1996 Linus Torvalds
- *
- */
-
-#include <asm/errno.h>
-
-/*
- * These two _must_ execute atomically wrt each other.
- */
-static inline void wake_one_more(struct semaphore *sem)
-{
-	atomic_inc(&sem->waking);
-}
-
-static inline int waking_non_zero(struct semaphore *sem)
-{
-	int ret;
-	unsigned long flags = 0;
-
-	spin_lock_irqsave(&semaphore_wake_lock, flags);
-	ret = 0;
-	if (atomic_read(&sem->waking) > 0) {
-		atomic_dec(&sem->waking);
-		ret = 1;
-	}
-	spin_unlock_irqrestore(&semaphore_wake_lock, flags);
-	return ret;
-}
-
-/*
- * waking_non_zero_interruptible:
- *	1	got the lock
- *	0	go to sleep
- *	-EINTR	interrupted
- */
-static inline int waking_non_zero_interruptible(struct semaphore *sem,
-						struct task_struct *tsk)
-{
-	int ret = 0;
-	unsigned long flags = 0;
-
-	spin_lock_irqsave(&semaphore_wake_lock, flags);
-	if (atomic_read(&sem->waking) > 0) {
-		atomic_dec(&sem->waking);
-		ret = 1;
-	} else if (signal_pending(tsk)) {
-		atomic_inc(&sem->count);
-		ret = -EINTR;
-	}
-	spin_unlock_irqrestore(&semaphore_wake_lock, flags);
-	return ret;
-}
-
-/*
- * waking_non_zero_trylock:
- *	1	failed to lock
- *	0	got the lock
- */
-static inline int waking_non_zero_trylock(struct semaphore *sem)
-{
-	int ret = 1;
-	unsigned long flags = 0;
-
-	spin_lock_irqsave(&semaphore_wake_lock, flags);
-	if (atomic_read(&sem->waking) > 0) {
-		atomic_dec(&sem->waking);
-		ret = 0;
-	} else
-		atomic_inc(&sem->count);
-	spin_unlock_irqrestore(&semaphore_wake_lock, flags);
-	return ret;
-}
-
-#endif				/* _BFIN_SEMAPHORE_HELPER_H */
diff --git a/include/asm-blackfin/semaphore.h b/include/asm-blackfin/semaphore.h
index 533f90fb2e4e..d9b2034ed1d2 100644
--- a/include/asm-blackfin/semaphore.h
+++ b/include/asm-blackfin/semaphore.h
@@ -1,105 +1 @@
-#ifndef _BFIN_SEMAPHORE_H
-#define _BFIN_SEMAPHORE_H
-
-#ifndef __ASSEMBLY__
-
-#include <linux/linkage.h>
-#include <linux/wait.h>
-#include <linux/spinlock.h>
-#include <linux/rwsem.h>
-#include <asm/atomic.h>
-
-/*
- * Interrupt-safe semaphores..
- *
- * (C) Copyright 1996 Linus Torvalds
- *
- * BFIN version by akbar hussain Lineo Inc  April 2001
- *
- */
-
-struct semaphore {
-	atomic_t count;
-	int sleepers;
-	wait_queue_head_t wait;
-};
-
-#define __SEMAPHORE_INITIALIZER(name, n)				\
-{									\
-	.count		= ATOMIC_INIT(n),				\
-	.sleepers	= 0,						\
-	.wait		= __WAIT_QUEUE_HEAD_INITIALIZER((name).wait)	\
-}
-
-#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
-	struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
-
-#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
-
-static inline void sema_init(struct semaphore *sem, int val)
-{
-	*sem = (struct semaphore)__SEMAPHORE_INITIALIZER(*sem, val);
-}
-
-static inline void init_MUTEX(struct semaphore *sem)
-{
-	sema_init(sem, 1);
-}
-
-static inline void init_MUTEX_LOCKED(struct semaphore *sem)
-{
-	sema_init(sem, 0);
-}
-
-asmlinkage void __down(struct semaphore *sem);
-asmlinkage int __down_interruptible(struct semaphore *sem);
-asmlinkage int __down_trylock(struct semaphore *sem);
-asmlinkage void __up(struct semaphore *sem);
-
-extern spinlock_t semaphore_wake_lock;
-
-/*
- * This is ugly, but we want the default case to fall through.
- * "down_failed" is a special asm handler that calls the C
- * routine that actually waits.
- */
-static inline void down(struct semaphore *sem)
-{
-	might_sleep();
-	if (atomic_dec_return(&sem->count) < 0)
-		__down(sem);
-}
-
-static inline int down_interruptible(struct semaphore *sem)
-{
-	int ret = 0;
-
-	might_sleep();
-	if (atomic_dec_return(&sem->count) < 0)
-		ret = __down_interruptible(sem);
-	return (ret);
-}
-
-static inline int down_trylock(struct semaphore *sem)
-{
-	int ret = 0;
-
-	if (atomic_dec_return(&sem->count) < 0)
-		ret = __down_trylock(sem);
-	return ret;
-}
-
-/*
- * Note! This is subtle. We jump to wake people up only if
- * the semaphore was negative (== somebody was waiting on it).
- * The default case (no contention) will result in NO
- * jumps for both down() and up().
- */
-static inline void up(struct semaphore *sem)
-{
-	if (atomic_inc_return(&sem->count) <= 0)
-		__up(sem);
-}
-
-#endif				/* __ASSEMBLY__ */
-#endif				/* _BFIN_SEMAPHORE_H */
+#include <linux/semaphore.h>