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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-xtensa
parente48b3deee475134585eed03e7afebe4bf9e0dba9 (diff)
downloadop-kernel-dev-64ac24e738823161693bf791f87adc802cf529ff.zip
op-kernel-dev-64ac24e738823161693bf791f87adc802cf529ff.tar.gz
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-xtensa')
-rw-r--r--include/asm-xtensa/semaphore.h100
1 files changed, 1 insertions, 99 deletions
diff --git a/include/asm-xtensa/semaphore.h b/include/asm-xtensa/semaphore.h
index 3e04167..d9b2034 100644
--- a/include/asm-xtensa/semaphore.h
+++ b/include/asm-xtensa/semaphore.h
@@ -1,99 +1 @@
-/*
- * linux/include/asm-xtensa/semaphore.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.
- *
- * Copyright (C) 2001 - 2005 Tensilica Inc.
- */
-
-#ifndef _XTENSA_SEMAPHORE_H
-#define _XTENSA_SEMAPHORE_H
-
-#include <asm/atomic.h>
-#include <asm/system.h>
-#include <linux/wait.h>
-#include <linux/rwsem.h>
-
-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)
-{
- atomic_set(&sem->count, val);
- sem->sleepers = 0;
- init_waitqueue_head(&sem->wait);
-}
-
-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;
-
-static inline void down(struct semaphore * sem)
-{
- might_sleep();
-
- if (atomic_sub_return(1, &sem->count) < 0)
- __down(sem);
-}
-
-static inline int down_interruptible(struct semaphore * sem)
-{
- int ret = 0;
-
- might_sleep();
-
- if (atomic_sub_return(1, &sem->count) < 0)
- ret = __down_interruptible(sem);
- return ret;
-}
-
-static inline int down_trylock(struct semaphore * sem)
-{
- int ret = 0;
-
- if (atomic_sub_return(1, &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).
- */
-static inline void up(struct semaphore * sem)
-{
- if (atomic_add_return(1, &sem->count) <= 0)
- __up(sem);
-}
-
-#endif /* _XTENSA_SEMAPHORE_H */
+#include <linux/semaphore.h>
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