73 lines
1.5 KiB
C
73 lines
1.5 KiB
C
|
/* 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 */
|