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authorMatthew Wilcox <matthew@wil.cx>2008-03-07 21:55:58 -0500
committerMatthew Wilcox <willy@linux.intel.com>2008-04-17 10:42:34 -0400
commit64ac24e738823161693bf791f87adc802cf529ff (patch)
tree19c0b0cf314d4394ca580c05b86cdf874ce0a167 /include/asm-frv
parente48b3deee475134585eed03e7afebe4bf9e0dba9 (diff)
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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>
Diffstat (limited to 'include/asm-frv')
-rw-r--r--include/asm-frv/semaphore.h156
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>