diff options
Diffstat (limited to 'include/asm-powerpc/semaphore.h')
-rw-r--r-- | include/asm-powerpc/semaphore.h | 95 |
1 files changed, 1 insertions, 94 deletions
diff --git a/include/asm-powerpc/semaphore.h b/include/asm-powerpc/semaphore.h index 48dd32e07749..d9b2034ed1d2 100644 --- a/include/asm-powerpc/semaphore.h +++ b/include/asm-powerpc/semaphore.h | |||
@@ -1,94 +1 @@ | |||
1 | #ifndef _ASM_POWERPC_SEMAPHORE_H | #include <linux/semaphore.h> | |
2 | #define _ASM_POWERPC_SEMAPHORE_H | ||
3 | |||
4 | /* | ||
5 | * Remove spinlock-based RW semaphores; RW semaphore definitions are | ||
6 | * now in rwsem.h and we use the generic lib/rwsem.c implementation. | ||
7 | * Rework semaphores to use atomic_dec_if_positive. | ||
8 | * -- Paul Mackerras (paulus@samba.org) | ||
9 | */ | ||
10 | |||
11 | #ifdef __KERNEL__ | ||
12 | |||
13 | #include <asm/atomic.h> | ||
14 | #include <asm/system.h> | ||
15 | #include <linux/wait.h> | ||
16 | #include <linux/rwsem.h> | ||
17 | |||
18 | struct semaphore { | ||
19 | /* | ||
20 | * Note that any negative value of count is equivalent to 0, | ||
21 | * but additionally indicates that some process(es) might be | ||
22 | * sleeping on `wait'. | ||
23 | */ | ||
24 | atomic_t count; | ||
25 | wait_queue_head_t wait; | ||
26 | }; | ||
27 | |||
28 | #define __SEMAPHORE_INITIALIZER(name, n) \ | ||
29 | { \ | ||
30 | .count = ATOMIC_INIT(n), \ | ||
31 | .wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \ | ||
32 | } | ||
33 | |||
34 | #define __DECLARE_SEMAPHORE_GENERIC(name, count) \ | ||
35 | struct semaphore name = __SEMAPHORE_INITIALIZER(name,count) | ||
36 | |||
37 | #define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name, 1) | ||
38 | |||
39 | static inline void sema_init (struct semaphore *sem, int val) | ||
40 | { | ||
41 | atomic_set(&sem->count, val); | ||
42 | init_waitqueue_head(&sem->wait); | ||
43 | } | ||
44 | |||
45 | static inline void init_MUTEX (struct semaphore *sem) | ||
46 | { | ||
47 | sema_init(sem, 1); | ||
48 | } | ||
49 | |||
50 | static inline void init_MUTEX_LOCKED (struct semaphore *sem) | ||
51 | { | ||
52 | sema_init(sem, 0); | ||
53 | } | ||
54 | |||
55 | extern void __down(struct semaphore * sem); | ||
56 | extern int __down_interruptible(struct semaphore * sem); | ||
57 | extern void __up(struct semaphore * sem); | ||
58 | |||
59 | static inline void down(struct semaphore * sem) | ||
60 | { | ||
61 | might_sleep(); | ||
62 | |||
63 | /* | ||
64 | * Try to get the semaphore, take the slow path if we fail. | ||
65 | */ | ||
66 | if (unlikely(atomic_dec_return(&sem->count) < 0)) | ||
67 | __down(sem); | ||
68 | } | ||
69 | |||
70 | static inline int down_interruptible(struct semaphore * sem) | ||
71 | { | ||
72 | int ret = 0; | ||
73 | |||
74 | might_sleep(); | ||
75 | |||
76 | if (unlikely(atomic_dec_return(&sem->count) < 0)) | ||
77 | ret = __down_interruptible(sem); | ||
78 | return ret; | ||
79 | } | ||
80 | |||
81 | static inline int down_trylock(struct semaphore * sem) | ||
82 | { | ||
83 | return atomic_dec_if_positive(&sem->count) < 0; | ||
84 | } | ||
85 | |||
86 | static inline void up(struct semaphore * sem) | ||
87 | { | ||
88 | if (unlikely(atomic_inc_return(&sem->count) <= 0)) | ||
89 | __up(sem); | ||
90 | } | ||
91 | |||
92 | #endif /* __KERNEL__ */ | ||
93 | |||
94 | #endif /* _ASM_POWERPC_SEMAPHORE_H */ | ||