diff options
author | Matthew Wilcox <matthew@wil.cx> | 2008-03-07 21:55:58 -0500 |
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committer | Matthew Wilcox <willy@linux.intel.com> | 2008-04-17 10:42:34 -0400 |
commit | 64ac24e738823161693bf791f87adc802cf529ff (patch) | |
tree | 19c0b0cf314d4394ca580c05b86cdf874ce0a167 /include/asm-ia64/semaphore.h | |
parent | e48b3deee475134585eed03e7afebe4bf9e0dba9 (diff) | |
download | op-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-ia64/semaphore.h')
-rw-r--r-- | include/asm-ia64/semaphore.h | 100 |
1 files changed, 1 insertions, 99 deletions
diff --git a/include/asm-ia64/semaphore.h b/include/asm-ia64/semaphore.h index d8393d1..d9b2034 100644 --- a/include/asm-ia64/semaphore.h +++ b/include/asm-ia64/semaphore.h @@ -1,99 +1 @@ -#ifndef _ASM_IA64_SEMAPHORE_H -#define _ASM_IA64_SEMAPHORE_H - -/* - * Copyright (C) 1998-2000 Hewlett-Packard Co - * Copyright (C) 1998-2000 David Mosberger-Tang <davidm@hpl.hp.com> - */ - -#include <linux/wait.h> -#include <linux/rwsem.h> - -#include <asm/atomic.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) -{ - *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); -extern int __down_interruptible (struct semaphore * sem); -extern int __down_trylock (struct semaphore * sem); -extern void __up (struct semaphore * sem); - -/* - * Atomically decrement the semaphore's count. If it goes negative, - * block the calling thread in the TASK_UNINTERRUPTIBLE state. - */ -static inline void -down (struct semaphore *sem) -{ - might_sleep(); - if (ia64_fetchadd(-1, &sem->count.counter, acq) < 1) - __down(sem); -} - -/* - * Atomically decrement the semaphore's count. If it goes negative, - * block the calling thread in the TASK_INTERRUPTIBLE state. - */ -static inline int -down_interruptible (struct semaphore * sem) -{ - int ret = 0; - - might_sleep(); - if (ia64_fetchadd(-1, &sem->count.counter, acq) < 1) - ret = __down_interruptible(sem); - return ret; -} - -static inline int -down_trylock (struct semaphore *sem) -{ - int ret = 0; - - if (ia64_fetchadd(-1, &sem->count.counter, acq) < 1) - ret = __down_trylock(sem); - return ret; -} - -static inline void -up (struct semaphore * sem) -{ - if (ia64_fetchadd(1, &sem->count.counter, rel) <= -1) - __up(sem); -} - -#endif /* _ASM_IA64_SEMAPHORE_H */ +#include <linux/semaphore.h> |