fs: use kmem_cache_zalloc instead
[pv_ops_mirror.git] / include / asm-xtensa / semaphore.h
blob3e04167cd9dce22d2989f18e569255ecb059b11d
1 /*
2 * linux/include/asm-xtensa/semaphore.h
4 * This file is subject to the terms and conditions of the GNU General Public
5 * License. See the file "COPYING" in the main directory of this archive
6 * for more details.
8 * Copyright (C) 2001 - 2005 Tensilica Inc.
9 */
11 #ifndef _XTENSA_SEMAPHORE_H
12 #define _XTENSA_SEMAPHORE_H
14 #include <asm/atomic.h>
15 #include <asm/system.h>
16 #include <linux/wait.h>
17 #include <linux/rwsem.h>
19 struct semaphore {
20 atomic_t count;
21 int sleepers;
22 wait_queue_head_t wait;
25 #define __SEMAPHORE_INITIALIZER(name,n) \
26 { \
27 .count = ATOMIC_INIT(n), \
28 .sleepers = 0, \
29 .wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
32 #define __DECLARE_SEMAPHORE_GENERIC(name,count) \
33 struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
35 #define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
37 static inline void sema_init (struct semaphore *sem, int val)
39 atomic_set(&sem->count, val);
40 sem->sleepers = 0;
41 init_waitqueue_head(&sem->wait);
44 static inline void init_MUTEX (struct semaphore *sem)
46 sema_init(sem, 1);
49 static inline void init_MUTEX_LOCKED (struct semaphore *sem)
51 sema_init(sem, 0);
54 asmlinkage void __down(struct semaphore * sem);
55 asmlinkage int __down_interruptible(struct semaphore * sem);
56 asmlinkage int __down_trylock(struct semaphore * sem);
57 asmlinkage void __up(struct semaphore * sem);
59 extern spinlock_t semaphore_wake_lock;
61 static inline void down(struct semaphore * sem)
63 might_sleep();
65 if (atomic_sub_return(1, &sem->count) < 0)
66 __down(sem);
69 static inline int down_interruptible(struct semaphore * sem)
71 int ret = 0;
73 might_sleep();
75 if (atomic_sub_return(1, &sem->count) < 0)
76 ret = __down_interruptible(sem);
77 return ret;
80 static inline int down_trylock(struct semaphore * sem)
82 int ret = 0;
84 if (atomic_sub_return(1, &sem->count) < 0)
85 ret = __down_trylock(sem);
86 return ret;
90 * Note! This is subtle. We jump to wake people up only if
91 * the semaphore was negative (== somebody was waiting on it).
93 static inline void up(struct semaphore * sem)
95 if (atomic_add_return(1, &sem->count) <= 0)
96 __up(sem);
99 #endif /* _XTENSA_SEMAPHORE_H */