diff options
author | Stephen Rothwell <sfr@canb.auug.org.au> | 2008-08-01 01:20:30 -0400 |
---|---|---|
committer | Paul Mackerras <paulus@samba.org> | 2008-08-03 22:02:00 -0400 |
commit | b8b572e1015f81b4e748417be2629dfe51ab99f9 (patch) | |
tree | 7df58667d5ed71d6c8f8f4ce40ca16b6fb776d0b /arch/powerpc/include/asm/rwsem.h | |
parent | 2b12a4c524812fb3f6ee590a02e65b95c8c32229 (diff) |
powerpc: Move include files to arch/powerpc/include/asm
from include/asm-powerpc. This is the result of a
mkdir arch/powerpc/include/asm
git mv include/asm-powerpc/* arch/powerpc/include/asm
Followed by a few documentation/comment fixups and a couple of places
where <asm-powepc/...> was being used explicitly. Of the latter only
one was outside the arch code and it is a driver only built for powerpc.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc/include/asm/rwsem.h')
-rw-r--r-- | arch/powerpc/include/asm/rwsem.h | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/rwsem.h b/arch/powerpc/include/asm/rwsem.h new file mode 100644 index 000000000000..24cd9281ec37 --- /dev/null +++ b/arch/powerpc/include/asm/rwsem.h | |||
@@ -0,0 +1,173 @@ | |||
1 | #ifndef _ASM_POWERPC_RWSEM_H | ||
2 | #define _ASM_POWERPC_RWSEM_H | ||
3 | |||
4 | #ifndef _LINUX_RWSEM_H | ||
5 | #error "Please don't include <asm/rwsem.h> directly, use <linux/rwsem.h> instead." | ||
6 | #endif | ||
7 | |||
8 | #ifdef __KERNEL__ | ||
9 | |||
10 | /* | ||
11 | * R/W semaphores for PPC using the stuff in lib/rwsem.c. | ||
12 | * Adapted largely from include/asm-i386/rwsem.h | ||
13 | * by Paul Mackerras <paulus@samba.org>. | ||
14 | */ | ||
15 | |||
16 | #include <linux/list.h> | ||
17 | #include <linux/spinlock.h> | ||
18 | #include <asm/atomic.h> | ||
19 | #include <asm/system.h> | ||
20 | |||
21 | /* | ||
22 | * the semaphore definition | ||
23 | */ | ||
24 | struct rw_semaphore { | ||
25 | /* XXX this should be able to be an atomic_t -- paulus */ | ||
26 | signed int count; | ||
27 | #define RWSEM_UNLOCKED_VALUE 0x00000000 | ||
28 | #define RWSEM_ACTIVE_BIAS 0x00000001 | ||
29 | #define RWSEM_ACTIVE_MASK 0x0000ffff | ||
30 | #define RWSEM_WAITING_BIAS (-0x00010000) | ||
31 | #define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS | ||
32 | #define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS) | ||
33 | spinlock_t wait_lock; | ||
34 | struct list_head wait_list; | ||
35 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | ||
36 | struct lockdep_map dep_map; | ||
37 | #endif | ||
38 | }; | ||
39 | |||
40 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | ||
41 | # define __RWSEM_DEP_MAP_INIT(lockname) , .dep_map = { .name = #lockname } | ||
42 | #else | ||
43 | # define __RWSEM_DEP_MAP_INIT(lockname) | ||
44 | #endif | ||
45 | |||
46 | #define __RWSEM_INITIALIZER(name) \ | ||
47 | { RWSEM_UNLOCKED_VALUE, __SPIN_LOCK_UNLOCKED((name).wait_lock), \ | ||
48 | LIST_HEAD_INIT((name).wait_list) __RWSEM_DEP_MAP_INIT(name) } | ||
49 | |||
50 | #define DECLARE_RWSEM(name) \ | ||
51 | struct rw_semaphore name = __RWSEM_INITIALIZER(name) | ||
52 | |||
53 | extern struct rw_semaphore *rwsem_down_read_failed(struct rw_semaphore *sem); | ||
54 | extern struct rw_semaphore *rwsem_down_write_failed(struct rw_semaphore *sem); | ||
55 | extern struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem); | ||
56 | extern struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem); | ||
57 | |||
58 | extern void __init_rwsem(struct rw_semaphore *sem, const char *name, | ||
59 | struct lock_class_key *key); | ||
60 | |||
61 | #define init_rwsem(sem) \ | ||
62 | do { \ | ||
63 | static struct lock_class_key __key; \ | ||
64 | \ | ||
65 | __init_rwsem((sem), #sem, &__key); \ | ||
66 | } while (0) | ||
67 | |||
68 | /* | ||
69 | * lock for reading | ||
70 | */ | ||
71 | static inline void __down_read(struct rw_semaphore *sem) | ||
72 | { | ||
73 | if (unlikely(atomic_inc_return((atomic_t *)(&sem->count)) <= 0)) | ||
74 | rwsem_down_read_failed(sem); | ||
75 | } | ||
76 | |||
77 | static inline int __down_read_trylock(struct rw_semaphore *sem) | ||
78 | { | ||
79 | int tmp; | ||
80 | |||
81 | while ((tmp = sem->count) >= 0) { | ||
82 | if (tmp == cmpxchg(&sem->count, tmp, | ||
83 | tmp + RWSEM_ACTIVE_READ_BIAS)) { | ||
84 | return 1; | ||
85 | } | ||
86 | } | ||
87 | return 0; | ||
88 | } | ||
89 | |||
90 | /* | ||
91 | * lock for writing | ||
92 | */ | ||
93 | static inline void __down_write_nested(struct rw_semaphore *sem, int subclass) | ||
94 | { | ||
95 | int tmp; | ||
96 | |||
97 | tmp = atomic_add_return(RWSEM_ACTIVE_WRITE_BIAS, | ||
98 | (atomic_t *)(&sem->count)); | ||
99 | if (unlikely(tmp != RWSEM_ACTIVE_WRITE_BIAS)) | ||
100 | rwsem_down_write_failed(sem); | ||
101 | } | ||
102 | |||
103 | static inline void __down_write(struct rw_semaphore *sem) | ||
104 | { | ||
105 | __down_write_nested(sem, 0); | ||
106 | } | ||
107 | |||
108 | static inline int __down_write_trylock(struct rw_semaphore *sem) | ||
109 | { | ||
110 | int tmp; | ||
111 | |||
112 | tmp = cmpxchg(&sem->count, RWSEM_UNLOCKED_VALUE, | ||
113 | RWSEM_ACTIVE_WRITE_BIAS); | ||
114 | return tmp == RWSEM_UNLOCKED_VALUE; | ||
115 | } | ||
116 | |||
117 | /* | ||
118 | * unlock after reading | ||
119 | */ | ||
120 | static inline void __up_read(struct rw_semaphore *sem) | ||
121 | { | ||
122 | int tmp; | ||
123 | |||
124 | tmp = atomic_dec_return((atomic_t *)(&sem->count)); | ||
125 | if (unlikely(tmp < -1 && (tmp & RWSEM_ACTIVE_MASK) == 0)) | ||
126 | rwsem_wake(sem); | ||
127 | } | ||
128 | |||
129 | /* | ||
130 | * unlock after writing | ||
131 | */ | ||
132 | static inline void __up_write(struct rw_semaphore *sem) | ||
133 | { | ||
134 | if (unlikely(atomic_sub_return(RWSEM_ACTIVE_WRITE_BIAS, | ||
135 | (atomic_t *)(&sem->count)) < 0)) | ||
136 | rwsem_wake(sem); | ||
137 | } | ||
138 | |||
139 | /* | ||
140 | * implement atomic add functionality | ||
141 | */ | ||
142 | static inline void rwsem_atomic_add(int delta, struct rw_semaphore *sem) | ||
143 | { | ||
144 | atomic_add(delta, (atomic_t *)(&sem->count)); | ||
145 | } | ||
146 | |||
147 | /* | ||
148 | * downgrade write lock to read lock | ||
149 | */ | ||
150 | static inline void __downgrade_write(struct rw_semaphore *sem) | ||
151 | { | ||
152 | int tmp; | ||
153 | |||
154 | tmp = atomic_add_return(-RWSEM_WAITING_BIAS, (atomic_t *)(&sem->count)); | ||
155 | if (tmp < 0) | ||
156 | rwsem_downgrade_wake(sem); | ||
157 | } | ||
158 | |||
159 | /* | ||
160 | * implement exchange and add functionality | ||
161 | */ | ||
162 | static inline int rwsem_atomic_update(int delta, struct rw_semaphore *sem) | ||
163 | { | ||
164 | return atomic_add_return(delta, (atomic_t *)(&sem->count)); | ||
165 | } | ||
166 | |||
167 | static inline int rwsem_is_locked(struct rw_semaphore *sem) | ||
168 | { | ||
169 | return (sem->count != 0); | ||
170 | } | ||
171 | |||
172 | #endif /* __KERNEL__ */ | ||
173 | #endif /* _ASM_POWERPC_RWSEM_H */ | ||