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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
da6d8567 ACM |
2 | #ifndef __TOOLS_ASM_GENERIC_ATOMIC_H |
3 | #define __TOOLS_ASM_GENERIC_ATOMIC_H | |
4 | ||
5 | #include <linux/compiler.h> | |
6 | #include <linux/types.h> | |
7 | ||
8 | /* | |
9 | * Atomic operations that C can't guarantee us. Useful for | |
10 | * resource counting etc.. | |
11 | * | |
12 | * Excerpts obtained from the Linux kernel sources. | |
13 | */ | |
14 | ||
15 | #define ATOMIC_INIT(i) { (i) } | |
16 | ||
17 | /** | |
18 | * atomic_read - read atomic variable | |
19 | * @v: pointer of type atomic_t | |
20 | * | |
21 | * Atomically reads the value of @v. | |
22 | */ | |
23 | static inline int atomic_read(const atomic_t *v) | |
24 | { | |
6aa7de05 | 25 | return READ_ONCE((v)->counter); |
da6d8567 ACM |
26 | } |
27 | ||
28 | /** | |
29 | * atomic_set - set atomic variable | |
30 | * @v: pointer of type atomic_t | |
31 | * @i: required value | |
32 | * | |
33 | * Atomically sets the value of @v to @i. | |
34 | */ | |
35 | static inline void atomic_set(atomic_t *v, int i) | |
36 | { | |
37 | v->counter = i; | |
38 | } | |
39 | ||
40 | /** | |
41 | * atomic_inc - increment atomic variable | |
42 | * @v: pointer of type atomic_t | |
43 | * | |
44 | * Atomically increments @v by 1. | |
45 | */ | |
46 | static inline void atomic_inc(atomic_t *v) | |
47 | { | |
48 | __sync_add_and_fetch(&v->counter, 1); | |
49 | } | |
50 | ||
51 | /** | |
52 | * atomic_dec_and_test - decrement and test | |
53 | * @v: pointer of type atomic_t | |
54 | * | |
55 | * Atomically decrements @v by 1 and | |
56 | * returns true if the result is 0, or false for all other | |
57 | * cases. | |
58 | */ | |
59 | static inline int atomic_dec_and_test(atomic_t *v) | |
60 | { | |
61 | return __sync_sub_and_fetch(&v->counter, 1) == 0; | |
62 | } | |
63 | ||
ed4aad50 ACM |
64 | #define cmpxchg(ptr, oldval, newval) \ |
65 | __sync_val_compare_and_swap(ptr, oldval, newval) | |
66 | ||
67 | static inline int atomic_cmpxchg(atomic_t *v, int oldval, int newval) | |
68 | { | |
69 | return cmpxchg(&(v)->counter, oldval, newval); | |
70 | } | |
71 | ||
da6d8567 | 72 | #endif /* __TOOLS_ASM_GENERIC_ATOMIC_H */ |