diff options
author | Matthew Wilcox <matthew@wil.cx> | 2008-03-07 21:55:58 -0500 |
---|---|---|
committer | Matthew Wilcox <willy@linux.intel.com> | 2008-04-17 10:42:34 -0400 |
commit | 64ac24e738823161693bf791f87adc802cf529ff (patch) | |
tree | 19c0b0cf314d4394ca580c05b86cdf874ce0a167 /include/asm-v850 | |
parent | e48b3deee475134585eed03e7afebe4bf9e0dba9 (diff) |
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-v850')
-rw-r--r-- | include/asm-v850/semaphore.h | 85 |
1 files changed, 1 insertions, 84 deletions
diff --git a/include/asm-v850/semaphore.h b/include/asm-v850/semaphore.h index 10ed0ccf37df..d9b2034ed1d2 100644 --- a/include/asm-v850/semaphore.h +++ b/include/asm-v850/semaphore.h | |||
@@ -1,84 +1 @@ | |||
1 | #ifndef __V850_SEMAPHORE_H__ | #include <linux/semaphore.h> | |
2 | #define __V850_SEMAPHORE_H__ | ||
3 | |||
4 | #include <linux/linkage.h> | ||
5 | #include <linux/spinlock.h> | ||
6 | #include <linux/wait.h> | ||
7 | #include <linux/rwsem.h> | ||
8 | |||
9 | #include <asm/atomic.h> | ||
10 | |||
11 | struct semaphore { | ||
12 | atomic_t count; | ||
13 | int sleepers; | ||
14 | wait_queue_head_t wait; | ||
15 | }; | ||
16 | |||
17 | #define __SEMAPHORE_INITIALIZER(name,count) \ | ||
18 | { ATOMIC_INIT (count), 0, \ | ||
19 | __WAIT_QUEUE_HEAD_INITIALIZER ((name).wait) } | ||
20 | |||
21 | #define __DECLARE_SEMAPHORE_GENERIC(name,count) \ | ||
22 | struct semaphore name = __SEMAPHORE_INITIALIZER (name,count) | ||
23 | |||
24 | #define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC (name,1) | ||
25 | |||
26 | static inline void sema_init (struct semaphore *sem, int val) | ||
27 | { | ||
28 | *sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val); | ||
29 | } | ||
30 | |||
31 | static inline void init_MUTEX (struct semaphore *sem) | ||
32 | { | ||
33 | sema_init (sem, 1); | ||
34 | } | ||
35 | |||
36 | static inline void init_MUTEX_LOCKED (struct semaphore *sem) | ||
37 | { | ||
38 | sema_init (sem, 0); | ||
39 | } | ||
40 | |||
41 | /* | ||
42 | * special register calling convention | ||
43 | */ | ||
44 | asmlinkage void __down_failed (void); | ||
45 | asmlinkage int __down_interruptible_failed (void); | ||
46 | asmlinkage int __down_trylock_failed (void); | ||
47 | asmlinkage void __up_wakeup (void); | ||
48 | |||
49 | extern void __down (struct semaphore * sem); | ||
50 | extern int __down_interruptible (struct semaphore * sem); | ||
51 | extern int __down_trylock (struct semaphore * sem); | ||
52 | extern void __up (struct semaphore * sem); | ||
53 | |||
54 | static inline void down (struct semaphore * sem) | ||
55 | { | ||
56 | might_sleep(); | ||
57 | if (atomic_dec_return (&sem->count) < 0) | ||
58 | __down (sem); | ||
59 | } | ||
60 | |||
61 | static inline int down_interruptible (struct semaphore * sem) | ||
62 | { | ||
63 | int ret = 0; | ||
64 | might_sleep(); | ||
65 | if (atomic_dec_return (&sem->count) < 0) | ||
66 | ret = __down_interruptible (sem); | ||
67 | return ret; | ||
68 | } | ||
69 | |||
70 | static inline int down_trylock (struct semaphore *sem) | ||
71 | { | ||
72 | int ret = 0; | ||
73 | if (atomic_dec_return (&sem->count) < 0) | ||
74 | ret = __down_trylock (sem); | ||
75 | return ret; | ||
76 | } | ||
77 | |||
78 | static inline void up (struct semaphore * sem) | ||
79 | { | ||
80 | if (atomic_inc_return (&sem->count) <= 0) | ||
81 | __up (sem); | ||
82 | } | ||
83 | |||
84 | #endif /* __V850_SEMAPHORE_H__ */ | ||