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3f7e212d | 1 | /* |
acac43e2 AS |
2 | * Generic C implementation of atomic counter operations. Usable on |
3 | * UP systems only. Do not include in machine independent code. | |
4 | * | |
3f7e212d AB |
5 | * Originally implemented for MN10300. |
6 | * | |
7 | * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. | |
8 | * Written by David Howells (dhowells@redhat.com) | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or | |
11 | * modify it under the terms of the GNU General Public Licence | |
12 | * as published by the Free Software Foundation; either version | |
13 | * 2 of the Licence, or (at your option) any later version. | |
14 | */ | |
15 | #ifndef __ASM_GENERIC_ATOMIC_H | |
16 | #define __ASM_GENERIC_ATOMIC_H | |
17 | ||
18 | #ifdef CONFIG_SMP | |
19 | #error not SMP safe | |
20 | #endif | |
21 | ||
22 | /* | |
23 | * Atomic operations that C can't guarantee us. Useful for | |
24 | * resource counting etc.. | |
25 | */ | |
26 | ||
27 | #define ATOMIC_INIT(i) { (i) } | |
28 | ||
29 | #ifdef __KERNEL__ | |
30 | ||
31 | /** | |
32 | * atomic_read - read atomic variable | |
33 | * @v: pointer of type atomic_t | |
34 | * | |
37682177 | 35 | * Atomically reads the value of @v. |
3f7e212d | 36 | */ |
f3d46f9d | 37 | #define atomic_read(v) (*(volatile int *)&(v)->counter) |
3f7e212d AB |
38 | |
39 | /** | |
40 | * atomic_set - set atomic variable | |
41 | * @v: pointer of type atomic_t | |
42 | * @i: required value | |
43 | * | |
37682177 | 44 | * Atomically sets the value of @v to @i. |
3f7e212d AB |
45 | */ |
46 | #define atomic_set(v, i) (((v)->counter) = (i)) | |
47 | ||
df9ee292 | 48 | #include <linux/irqflags.h> |
3f7e212d AB |
49 | #include <asm/system.h> |
50 | ||
51 | /** | |
52 | * atomic_add_return - add integer to atomic variable | |
53 | * @i: integer value to add | |
54 | * @v: pointer of type atomic_t | |
55 | * | |
56 | * Atomically adds @i to @v and returns the result | |
3f7e212d AB |
57 | */ |
58 | static inline int atomic_add_return(int i, atomic_t *v) | |
59 | { | |
60 | unsigned long flags; | |
61 | int temp; | |
62 | ||
df9ee292 | 63 | raw_local_irq_save(flags); /* Don't trace it in an irqsoff handler */ |
3f7e212d AB |
64 | temp = v->counter; |
65 | temp += i; | |
66 | v->counter = temp; | |
9e58143d | 67 | raw_local_irq_restore(flags); |
3f7e212d AB |
68 | |
69 | return temp; | |
70 | } | |
71 | ||
72 | /** | |
73 | * atomic_sub_return - subtract integer from atomic variable | |
74 | * @i: integer value to subtract | |
75 | * @v: pointer of type atomic_t | |
76 | * | |
77 | * Atomically subtracts @i from @v and returns the result | |
3f7e212d AB |
78 | */ |
79 | static inline int atomic_sub_return(int i, atomic_t *v) | |
80 | { | |
81 | unsigned long flags; | |
82 | int temp; | |
83 | ||
df9ee292 | 84 | raw_local_irq_save(flags); /* Don't trace it in an irqsoff handler */ |
3f7e212d AB |
85 | temp = v->counter; |
86 | temp -= i; | |
87 | v->counter = temp; | |
9e58143d | 88 | raw_local_irq_restore(flags); |
3f7e212d AB |
89 | |
90 | return temp; | |
91 | } | |
92 | ||
93 | static inline int atomic_add_negative(int i, atomic_t *v) | |
94 | { | |
95 | return atomic_add_return(i, v) < 0; | |
96 | } | |
97 | ||
98 | static inline void atomic_add(int i, atomic_t *v) | |
99 | { | |
100 | atomic_add_return(i, v); | |
101 | } | |
102 | ||
103 | static inline void atomic_sub(int i, atomic_t *v) | |
104 | { | |
105 | atomic_sub_return(i, v); | |
106 | } | |
107 | ||
108 | static inline void atomic_inc(atomic_t *v) | |
109 | { | |
110 | atomic_add_return(1, v); | |
111 | } | |
112 | ||
113 | static inline void atomic_dec(atomic_t *v) | |
114 | { | |
115 | atomic_sub_return(1, v); | |
116 | } | |
117 | ||
118 | #define atomic_dec_return(v) atomic_sub_return(1, (v)) | |
119 | #define atomic_inc_return(v) atomic_add_return(1, (v)) | |
120 | ||
121 | #define atomic_sub_and_test(i, v) (atomic_sub_return((i), (v)) == 0) | |
3eea44ea MF |
122 | #define atomic_dec_and_test(v) (atomic_dec_return(v) == 0) |
123 | #define atomic_inc_and_test(v) (atomic_inc_return(v) == 0) | |
3f7e212d | 124 | |
8b9d4069 ML |
125 | #define atomic_xchg(ptr, v) (xchg(&(ptr)->counter, (v))) |
126 | #define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new))) | |
127 | ||
128 | #define cmpxchg_local(ptr, o, n) \ | |
129 | ((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\ | |
130 | (unsigned long)(n), sizeof(*(ptr)))) | |
131 | ||
132 | #define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n)) | |
133 | ||
f24219b4 | 134 | static inline int __atomic_add_unless(atomic_t *v, int a, int u) |
8b9d4069 ML |
135 | { |
136 | int c, old; | |
137 | c = atomic_read(v); | |
138 | while (c != u && (old = atomic_cmpxchg(v, c, c + a)) != c) | |
139 | c = old; | |
f24219b4 | 140 | return c; |
8b9d4069 | 141 | } |
3f7e212d | 142 | |
f6081bd3 MF |
143 | /** |
144 | * atomic_clear_mask - Atomically clear bits in atomic variable | |
145 | * @mask: Mask of the bits to be cleared | |
146 | * @v: pointer of type atomic_t | |
147 | * | |
148 | * Atomically clears the bits set in @mask from @v | |
149 | */ | |
150 | static inline void atomic_clear_mask(unsigned long mask, atomic_t *v) | |
3f7e212d AB |
151 | { |
152 | unsigned long flags; | |
153 | ||
154 | mask = ~mask; | |
9e58143d | 155 | raw_local_irq_save(flags); /* Don't trace it in a irqsoff handler */ |
f6081bd3 | 156 | v->counter &= mask; |
9e58143d | 157 | raw_local_irq_restore(flags); |
3f7e212d AB |
158 | } |
159 | ||
3f7e212d AB |
160 | /* Assume that atomic operations are already serializing */ |
161 | #define smp_mb__before_atomic_dec() barrier() | |
162 | #define smp_mb__after_atomic_dec() barrier() | |
163 | #define smp_mb__before_atomic_inc() barrier() | |
164 | #define smp_mb__after_atomic_inc() barrier() | |
165 | ||
3f7e212d AB |
166 | #endif /* __KERNEL__ */ |
167 | #endif /* __ASM_GENERIC_ATOMIC_H */ |