/* SPDX-License-Identifier: GPL-2.0 */ #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 READ_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; } #define cmpxchg(ptr, oldval, newval) \ __sync_val_compare_and_swap(ptr, oldval, newval) static inline int atomic_cmpxchg(atomic_t *v, int oldval, int newval) { return cmpxchg(&(v)->counter, oldval, newval); } #endif /* __TOOLS_ASM_GENERIC_ATOMIC_H */ |