fs: use kmem_cache_zalloc instead
[pv_ops_mirror.git] / include / asm-sh / semaphore.h
blob9e5a37c4dce2d297eaf9f2162910495c1fae4f8d
1 #ifndef __ASM_SH_SEMAPHORE_H
2 #define __ASM_SH_SEMAPHORE_H
4 #include <linux/linkage.h>
6 #ifdef __KERNEL__
7 /*
8 * SMP- and interrupt-safe semaphores.
10 * (C) Copyright 1996 Linus Torvalds
12 * SuperH verison by Niibe Yutaka
13 * (Currently no asm implementation but generic C code...)
16 #include <linux/spinlock.h>
17 #include <linux/rwsem.h>
18 #include <linux/wait.h>
20 #include <asm/system.h>
21 #include <asm/atomic.h>
23 struct semaphore {
24 atomic_t count;
25 int sleepers;
26 wait_queue_head_t wait;
29 #define __SEMAPHORE_INITIALIZER(name, n) \
30 { \
31 .count = ATOMIC_INIT(n), \
32 .sleepers = 0, \
33 .wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
36 #define __DECLARE_SEMAPHORE_GENERIC(name,count) \
37 struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
39 #define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
41 static inline void sema_init (struct semaphore *sem, int val)
44 * *sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val);
46 * i'd rather use the more flexible initialization above, but sadly
47 * GCC 2.7.2.3 emits a bogus warning. EGCS doesn't. Oh well.
49 atomic_set(&sem->count, val);
50 sem->sleepers = 0;
51 init_waitqueue_head(&sem->wait);
54 static inline void init_MUTEX (struct semaphore *sem)
56 sema_init(sem, 1);
59 static inline void init_MUTEX_LOCKED (struct semaphore *sem)
61 sema_init(sem, 0);
64 #if 0
65 asmlinkage void __down_failed(void /* special register calling convention */);
66 asmlinkage int __down_failed_interruptible(void /* params in registers */);
67 asmlinkage int __down_failed_trylock(void /* params in registers */);
68 asmlinkage void __up_wakeup(void /* special register calling convention */);
69 #endif
71 asmlinkage void __down(struct semaphore * sem);
72 asmlinkage int __down_interruptible(struct semaphore * sem);
73 asmlinkage int __down_trylock(struct semaphore * sem);
74 asmlinkage void __up(struct semaphore * sem);
76 extern spinlock_t semaphore_wake_lock;
78 static inline void down(struct semaphore * sem)
80 might_sleep();
81 if (atomic_dec_return(&sem->count) < 0)
82 __down(sem);
85 static inline int down_interruptible(struct semaphore * sem)
87 int ret = 0;
89 might_sleep();
90 if (atomic_dec_return(&sem->count) < 0)
91 ret = __down_interruptible(sem);
92 return ret;
95 static inline int down_trylock(struct semaphore * sem)
97 int ret = 0;
99 if (atomic_dec_return(&sem->count) < 0)
100 ret = __down_trylock(sem);
101 return ret;
105 * Note! This is subtle. We jump to wake people up only if
106 * the semaphore was negative (== somebody was waiting on it).
108 static inline void up(struct semaphore * sem)
110 if (atomic_inc_return(&sem->count) <= 0)
111 __up(sem);
114 #endif
115 #endif /* __ASM_SH_SEMAPHORE_H */