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