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>

1 files changed, 1 insertions, 155 deletions

diff --git a/include/asm-frv/semaphore.h b/include/asm-frv/semaphore.h
index d7aaa1911a1..d9b2034ed1d 100644
--- a/include/asm-frv/semaphore.h
+++ b/include/asm-frv/semaphore.h
@@ -1,155 +1 @@
-/* semaphore.h: semaphores for the FR-V
- *
- * Copyright (C) 2003 Red Hat, Inc. All Rights Reserved.
- * Written by David Howells (dhowells@redhat.com)
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version
- * 2 of the License, or (at your option) any later version.
- */
-#ifndef _ASM_SEMAPHORE_H
-#define _ASM_SEMAPHORE_H
-
-#define RW_LOCK_BIAS		 0x01000000
-
-#ifndef __ASSEMBLY__
-
-#include <linux/linkage.h>
-#include <linux/wait.h>
-#include <linux/spinlock.h>
-#include <linux/rwsem.h>
-
-/*
- * the semaphore definition
- * - if counter is >0 then there are tokens available on the semaphore for down to collect
- * - if counter is <=0 then there are no spare tokens, and anyone that wants one must wait
- * - if wait_list is not empty, then there are processes waiting for the semaphore
- */
-struct semaphore {
-	unsigned		counter;
-	spinlock_t		wait_lock;
-	struct list_head	wait_list;
-#ifdef CONFIG_DEBUG_SEMAPHORE
-	unsigned		__magic;
-#endif
-};
-
-#ifdef CONFIG_DEBUG_SEMAPHORE
-# define __SEM_DEBUG_INIT(name) , (long)&(name).__magic
-#else
-# define __SEM_DEBUG_INIT(name)
-#endif
-
-
-#define __SEMAPHORE_INITIALIZER(name,count) \
-{ count, SPIN_LOCK_UNLOCKED, LIST_HEAD_INIT((name).wait_list) __SEM_DEBUG_INIT(name) }
-
-#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);
-}
-
-extern void __down(struct semaphore *sem, unsigned long flags);
-extern int  __down_interruptible(struct semaphore *sem, unsigned long flags);
-extern void __up(struct semaphore *sem);
-
-static inline void down(struct semaphore *sem)
-{
-	unsigned long flags;
-
-#ifdef CONFIG_DEBUG_SEMAPHORE
-	CHECK_MAGIC(sem->__magic);
-#endif
-
-	spin_lock_irqsave(&sem->wait_lock, flags);
-	if (likely(sem->counter > 0)) {
-		sem->counter--;
-		spin_unlock_irqrestore(&sem->wait_lock, flags);
-	}
-	else {
-		__down(sem, flags);
-	}
-}
-
-static inline int down_interruptible(struct semaphore *sem)
-{
-	unsigned long flags;
-	int ret = 0;
-
-#ifdef CONFIG_DEBUG_SEMAPHORE
-	CHECK_MAGIC(sem->__magic);
-#endif
-
-	spin_lock_irqsave(&sem->wait_lock, flags);
-	if (likely(sem->counter > 0)) {
-		sem->counter--;
-		spin_unlock_irqrestore(&sem->wait_lock, flags);
-	}
-	else {
-		ret = __down_interruptible(sem, flags);
-	}
-	return ret;
-}
-
-/*
- * non-blockingly attempt to down() a semaphore.
- * - returns zero if we acquired it
- */
-static inline int down_trylock(struct semaphore *sem)
-{
-	unsigned long flags;
-	int success = 0;
-
-#ifdef CONFIG_DEBUG_SEMAPHORE
-	CHECK_MAGIC(sem->__magic);
-#endif
-
-	spin_lock_irqsave(&sem->wait_lock, flags);
-	if (sem->counter > 0) {
-		sem->counter--;
-		success = 1;
-	}
-	spin_unlock_irqrestore(&sem->wait_lock, flags);
-	return !success;
-}
-
-static inline void up(struct semaphore *sem)
-{
-	unsigned long flags;
-
-#ifdef CONFIG_DEBUG_SEMAPHORE
-	CHECK_MAGIC(sem->__magic);
-#endif
-
-	spin_lock_irqsave(&sem->wait_lock, flags);
-	if (!list_empty(&sem->wait_list))
-		__up(sem);
-	else
-		sem->counter++;
-	spin_unlock_irqrestore(&sem->wait_lock, flags);
-}
-
-static inline int sem_getcount(struct semaphore *sem)
-{
-	return sem->counter;
-}
-
-#endif /* __ASSEMBLY__ */
-
-#endif
+#include <linux/semaphore.h>