diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /include/asm-parisc/semaphore.h |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'include/asm-parisc/semaphore.h')
-rw-r--r-- | include/asm-parisc/semaphore.h | 147 |
1 files changed, 147 insertions, 0 deletions
diff --git a/include/asm-parisc/semaphore.h b/include/asm-parisc/semaphore.h new file mode 100644 index 000000000000..f78bb2e34538 --- /dev/null +++ b/include/asm-parisc/semaphore.h | |||
@@ -0,0 +1,147 @@ | |||
1 | /* SMP- and interrupt-safe semaphores. | ||
2 | * PA-RISC version by Matthew Wilcox | ||
3 | * | ||
4 | * Linux/PA-RISC Project (http://www.parisc-linux.org/) | ||
5 | * Copyright (C) 1996 Linus Torvalds | ||
6 | * Copyright (C) 1999-2001 Matthew Wilcox < willy at debian d0T org > | ||
7 | * Copyright (C) 2000 Grant Grundler < grundler a debian org > | ||
8 | * | ||
9 | * This program is free software; you can redistribute it and/or modify | ||
10 | * it under the terms of the GNU General Public License as published by | ||
11 | * the Free Software Foundation; either version 2 of the License, or | ||
12 | * (at your option) any later version. | ||
13 | * | ||
14 | * This program is distributed in the hope that it will be useful, | ||
15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | ||
17 | * GNU General Public License for more details. | ||
18 | * | ||
19 | * You should have received a copy of the GNU General Public License | ||
20 | * along with this program; if not, write to the Free Software | ||
21 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | ||
22 | */ | ||
23 | |||
24 | #ifndef _ASM_PARISC_SEMAPHORE_H | ||
25 | #define _ASM_PARISC_SEMAPHORE_H | ||
26 | |||
27 | #include <linux/spinlock.h> | ||
28 | #include <linux/wait.h> | ||
29 | #include <linux/rwsem.h> | ||
30 | |||
31 | #include <asm/system.h> | ||
32 | |||
33 | /* | ||
34 | * The `count' is initialised to the number of people who are allowed to | ||
35 | * take the lock. (Normally we want a mutex, so this is `1'). if | ||
36 | * `count' is positive, the lock can be taken. if it's 0, no-one is | ||
37 | * waiting on it. if it's -1, at least one task is waiting. | ||
38 | */ | ||
39 | struct semaphore { | ||
40 | spinlock_t sentry; | ||
41 | int count; | ||
42 | wait_queue_head_t wait; | ||
43 | }; | ||
44 | |||
45 | #define __SEMAPHORE_INITIALIZER(name, n) \ | ||
46 | { \ | ||
47 | .sentry = SPIN_LOCK_UNLOCKED, \ | ||
48 | .count = n, \ | ||
49 | .wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \ | ||
50 | } | ||
51 | |||
52 | #define __MUTEX_INITIALIZER(name) \ | ||
53 | __SEMAPHORE_INITIALIZER(name,1) | ||
54 | |||
55 | #define __DECLARE_SEMAPHORE_GENERIC(name,count) \ | ||
56 | struct semaphore name = __SEMAPHORE_INITIALIZER(name,count) | ||
57 | |||
58 | #define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1) | ||
59 | #define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0) | ||
60 | |||
61 | extern inline void sema_init (struct semaphore *sem, int val) | ||
62 | { | ||
63 | *sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val); | ||
64 | } | ||
65 | |||
66 | static inline void init_MUTEX (struct semaphore *sem) | ||
67 | { | ||
68 | sema_init(sem, 1); | ||
69 | } | ||
70 | |||
71 | static inline void init_MUTEX_LOCKED (struct semaphore *sem) | ||
72 | { | ||
73 | sema_init(sem, 0); | ||
74 | } | ||
75 | |||
76 | static inline int sem_getcount(struct semaphore *sem) | ||
77 | { | ||
78 | return sem->count; | ||
79 | } | ||
80 | |||
81 | asmlinkage void __down(struct semaphore * sem); | ||
82 | asmlinkage int __down_interruptible(struct semaphore * sem); | ||
83 | asmlinkage void __up(struct semaphore * sem); | ||
84 | |||
85 | /* Semaphores can be `tried' from irq context. So we have to disable | ||
86 | * interrupts while we're messing with the semaphore. Sorry. | ||
87 | */ | ||
88 | |||
89 | extern __inline__ void down(struct semaphore * sem) | ||
90 | { | ||
91 | might_sleep(); | ||
92 | spin_lock_irq(&sem->sentry); | ||
93 | if (sem->count > 0) { | ||
94 | sem->count--; | ||
95 | } else { | ||
96 | __down(sem); | ||
97 | } | ||
98 | spin_unlock_irq(&sem->sentry); | ||
99 | } | ||
100 | |||
101 | extern __inline__ int down_interruptible(struct semaphore * sem) | ||
102 | { | ||
103 | int ret = 0; | ||
104 | might_sleep(); | ||
105 | spin_lock_irq(&sem->sentry); | ||
106 | if (sem->count > 0) { | ||
107 | sem->count--; | ||
108 | } else { | ||
109 | ret = __down_interruptible(sem); | ||
110 | } | ||
111 | spin_unlock_irq(&sem->sentry); | ||
112 | return ret; | ||
113 | } | ||
114 | |||
115 | /* | ||
116 | * down_trylock returns 0 on success, 1 if we failed to get the lock. | ||
117 | * May not sleep, but must preserve irq state | ||
118 | */ | ||
119 | extern __inline__ int down_trylock(struct semaphore * sem) | ||
120 | { | ||
121 | int flags, count; | ||
122 | |||
123 | spin_lock_irqsave(&sem->sentry, flags); | ||
124 | count = sem->count - 1; | ||
125 | if (count >= 0) | ||
126 | sem->count = count; | ||
127 | spin_unlock_irqrestore(&sem->sentry, flags); | ||
128 | return (count < 0); | ||
129 | } | ||
130 | |||
131 | /* | ||
132 | * Note! This is subtle. We jump to wake people up only if | ||
133 | * the semaphore was negative (== somebody was waiting on it). | ||
134 | */ | ||
135 | extern __inline__ void up(struct semaphore * sem) | ||
136 | { | ||
137 | int flags; | ||
138 | spin_lock_irqsave(&sem->sentry, flags); | ||
139 | if (sem->count < 0) { | ||
140 | __up(sem); | ||
141 | } else { | ||
142 | sem->count++; | ||
143 | } | ||
144 | spin_unlock_irqrestore(&sem->sentry, flags); | ||
145 | } | ||
146 | |||
147 | #endif /* _ASM_PARISC_SEMAPHORE_H */ | ||