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authorPaul Mundt <lethal@linux-sh.org>2008-07-28 19:09:44 -0400
committerPaul Mundt <lethal@linux-sh.org>2008-07-28 19:09:44 -0400
commitf15cbe6f1a4b4d9df59142fc8e4abb973302cf44 (patch)
tree774d7b11abaaf33561ab8268bf51ddd9ceb79025 /include/asm-sh/rwsem.h
parent25326277d8d1393d1c66240e6255aca780f9e3eb (diff)
sh: migrate to arch/sh/include/
This follows the sparc changes a439fe51a1f8eb087c22dd24d69cebae4a3addac. Most of the moving about was done with Sam's directions at: http://marc.info/?l=linux-sh&m=121724823706062&w=2 with subsequent hacking and fixups entirely my fault. Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Diffstat (limited to 'include/asm-sh/rwsem.h')
-rw-r--r--include/asm-sh/rwsem.h188
1 files changed, 0 insertions, 188 deletions
diff --git a/include/asm-sh/rwsem.h b/include/asm-sh/rwsem.h
deleted file mode 100644
index 1987f3ea7f1b..000000000000
--- a/include/asm-sh/rwsem.h
+++ /dev/null
@@ -1,188 +0,0 @@
1/*
2 * include/asm-sh/rwsem.h: R/W semaphores for SH using the stuff
3 * in lib/rwsem.c.
4 */
5
6#ifndef _ASM_SH_RWSEM_H
7#define _ASM_SH_RWSEM_H
8
9#ifndef _LINUX_RWSEM_H
10#error "please don't include asm/rwsem.h directly, use linux/rwsem.h instead"
11#endif
12
13#ifdef __KERNEL__
14#include <linux/list.h>
15#include <linux/spinlock.h>
16#include <asm/atomic.h>
17#include <asm/system.h>
18
19/*
20 * the semaphore definition
21 */
22struct rw_semaphore {
23 long count;
24#define RWSEM_UNLOCKED_VALUE 0x00000000
25#define RWSEM_ACTIVE_BIAS 0x00000001
26#define RWSEM_ACTIVE_MASK 0x0000ffff
27#define RWSEM_WAITING_BIAS (-0x00010000)
28#define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS
29#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS)
30 spinlock_t wait_lock;
31 struct list_head wait_list;
32#ifdef CONFIG_DEBUG_LOCK_ALLOC
33 struct lockdep_map dep_map;
34#endif
35};
36
37#ifdef CONFIG_DEBUG_LOCK_ALLOC
38# define __RWSEM_DEP_MAP_INIT(lockname) , .dep_map = { .name = #lockname }
39#else
40# define __RWSEM_DEP_MAP_INIT(lockname)
41#endif
42
43#define __RWSEM_INITIALIZER(name) \
44 { RWSEM_UNLOCKED_VALUE, SPIN_LOCK_UNLOCKED, \
45 LIST_HEAD_INIT((name).wait_list) \
46 __RWSEM_DEP_MAP_INIT(name) }
47
48#define DECLARE_RWSEM(name) \
49 struct rw_semaphore name = __RWSEM_INITIALIZER(name)
50
51extern struct rw_semaphore *rwsem_down_read_failed(struct rw_semaphore *sem);
52extern struct rw_semaphore *rwsem_down_write_failed(struct rw_semaphore *sem);
53extern struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem);
54extern struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem);
55
56extern void __init_rwsem(struct rw_semaphore *sem, const char *name,
57 struct lock_class_key *key);
58
59#define init_rwsem(sem) \
60do { \
61 static struct lock_class_key __key; \
62 \
63 __init_rwsem((sem), #sem, &__key); \
64} while (0)
65
66static inline void init_rwsem(struct rw_semaphore *sem)
67{
68 sem->count = RWSEM_UNLOCKED_VALUE;
69 spin_lock_init(&sem->wait_lock);
70 INIT_LIST_HEAD(&sem->wait_list);
71}
72
73/*
74 * lock for reading
75 */
76static inline void __down_read(struct rw_semaphore *sem)
77{
78 if (atomic_inc_return((atomic_t *)(&sem->count)) > 0)
79 smp_wmb();
80 else
81 rwsem_down_read_failed(sem);
82}
83
84static inline int __down_read_trylock(struct rw_semaphore *sem)
85{
86 int tmp;
87
88 while ((tmp = sem->count) >= 0) {
89 if (tmp == cmpxchg(&sem->count, tmp,
90 tmp + RWSEM_ACTIVE_READ_BIAS)) {
91 smp_wmb();
92 return 1;
93 }
94 }
95 return 0;
96}
97
98/*
99 * lock for writing
100 */
101static inline void __down_write(struct rw_semaphore *sem)
102{
103 int tmp;
104
105 tmp = atomic_add_return(RWSEM_ACTIVE_WRITE_BIAS,
106 (atomic_t *)(&sem->count));
107 if (tmp == RWSEM_ACTIVE_WRITE_BIAS)
108 smp_wmb();
109 else
110 rwsem_down_write_failed(sem);
111}
112
113static inline int __down_write_trylock(struct rw_semaphore *sem)
114{
115 int tmp;
116
117 tmp = cmpxchg(&sem->count, RWSEM_UNLOCKED_VALUE,
118 RWSEM_ACTIVE_WRITE_BIAS);
119 smp_wmb();
120 return tmp == RWSEM_UNLOCKED_VALUE;
121}
122
123/*
124 * unlock after reading
125 */
126static inline void __up_read(struct rw_semaphore *sem)
127{
128 int tmp;
129
130 smp_wmb();
131 tmp = atomic_dec_return((atomic_t *)(&sem->count));
132 if (tmp < -1 && (tmp & RWSEM_ACTIVE_MASK) == 0)
133 rwsem_wake(sem);
134}
135
136/*
137 * unlock after writing
138 */
139static inline void __up_write(struct rw_semaphore *sem)
140{
141 smp_wmb();
142 if (atomic_sub_return(RWSEM_ACTIVE_WRITE_BIAS,
143 (atomic_t *)(&sem->count)) < 0)
144 rwsem_wake(sem);
145}
146
147/*
148 * implement atomic add functionality
149 */
150static inline void rwsem_atomic_add(int delta, struct rw_semaphore *sem)
151{
152 atomic_add(delta, (atomic_t *)(&sem->count));
153}
154
155/*
156 * downgrade write lock to read lock
157 */
158static inline void __downgrade_write(struct rw_semaphore *sem)
159{
160 int tmp;
161
162 smp_wmb();
163 tmp = atomic_add_return(-RWSEM_WAITING_BIAS, (atomic_t *)(&sem->count));
164 if (tmp < 0)
165 rwsem_downgrade_wake(sem);
166}
167
168static inline void __down_write_nested(struct rw_semaphore *sem, int subclass)
169{
170 __down_write(sem);
171}
172
173/*
174 * implement exchange and add functionality
175 */
176static inline int rwsem_atomic_update(int delta, struct rw_semaphore *sem)
177{
178 smp_mb();
179 return atomic_add_return(delta, (atomic_t *)(&sem->count));
180}
181
182static inline int rwsem_is_locked(struct rw_semaphore *sem)
183{
184 return (sem->count != 0);
185}
186
187#endif /* __KERNEL__ */
188#endif /* _ASM_SH_RWSEM_H */
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