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author | Russell King <rmk+kernel@arm.linux.org.uk> | 2015-07-07 12:35:33 +0100 |
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committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2015-07-07 12:35:33 +0100 |
commit | 06be5eefe1192eb8ce8d07497f67595b6bfe9741 (patch) | |
tree | 80f1987d4970f8079681f8be0c135cafc8d6329a /tools/include/asm-generic/atomic-gcc.h | |
parent | ARM: fix lockdep unannotated irqs-off warning (diff) | |
parent | ARM: avoid unwanted GCC memset()/memcpy() optimisations for IO variants (diff) | |
download | linux-dev-06be5eefe1192eb8ce8d07497f67595b6bfe9741.tar.xz linux-dev-06be5eefe1192eb8ce8d07497f67595b6bfe9741.zip |
Merge branches 'fixes' and 'ioremap' into for-linus
Diffstat (limited to 'tools/include/asm-generic/atomic-gcc.h')
-rw-r--r-- | tools/include/asm-generic/atomic-gcc.h | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/tools/include/asm-generic/atomic-gcc.h b/tools/include/asm-generic/atomic-gcc.h new file mode 100644 index 000000000000..2ba78c9f5701 --- /dev/null +++ b/tools/include/asm-generic/atomic-gcc.h @@ -0,0 +1,63 @@ +#ifndef __TOOLS_ASM_GENERIC_ATOMIC_H +#define __TOOLS_ASM_GENERIC_ATOMIC_H + +#include <linux/compiler.h> +#include <linux/types.h> + +/* + * Atomic operations that C can't guarantee us. Useful for + * resource counting etc.. + * + * Excerpts obtained from the Linux kernel sources. + */ + +#define ATOMIC_INIT(i) { (i) } + +/** + * atomic_read - read atomic variable + * @v: pointer of type atomic_t + * + * Atomically reads the value of @v. + */ +static inline int atomic_read(const atomic_t *v) +{ + return ACCESS_ONCE((v)->counter); +} + +/** + * atomic_set - set atomic variable + * @v: pointer of type atomic_t + * @i: required value + * + * Atomically sets the value of @v to @i. + */ +static inline void atomic_set(atomic_t *v, int i) +{ + v->counter = i; +} + +/** + * atomic_inc - increment atomic variable + * @v: pointer of type atomic_t + * + * Atomically increments @v by 1. + */ +static inline void atomic_inc(atomic_t *v) +{ + __sync_add_and_fetch(&v->counter, 1); +} + +/** + * atomic_dec_and_test - decrement and test + * @v: pointer of type atomic_t + * + * Atomically decrements @v by 1 and + * returns true if the result is 0, or false for all other + * cases. + */ +static inline int atomic_dec_and_test(atomic_t *v) +{ + return __sync_sub_and_fetch(&v->counter, 1) == 0; +} + +#endif /* __TOOLS_ASM_GENERIC_ATOMIC_H */ |