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#ifndef __BP_ATOMIC_H
#define __BP_ATOMIC_H
#include_next <linux/atomic.h>
/* atomic_cmpxchg_relaxed */
#ifndef atomic_cmpxchg_relaxed
#define atomic_cmpxchg_relaxed atomic_cmpxchg
#define atomic_cmpxchg_acquire atomic_cmpxchg
#define atomic_cmpxchg_release atomic_cmpxchg
#else /* atomic_cmpxchg_relaxed */
#ifndef atomic_cmpxchg_acquire
#define atomic_cmpxchg_acquire(...) \
__atomic_op_acquire(atomic_cmpxchg, __VA_ARGS__)
#endif
#ifndef atomic_cmpxchg_release
#define atomic_cmpxchg_release(...) \
__atomic_op_release(atomic_cmpxchg, __VA_ARGS__)
#endif
#ifndef atomic_cmpxchg
#define atomic_cmpxchg(...) \
__atomic_op_fence(atomic_cmpxchg, __VA_ARGS__)
#endif
#endif /* atomic_cmpxchg_relaxed */
/* these were introduced together, so just a single check is enough */
#ifndef atomic_try_cmpxchg_acquire
#ifndef atomic_try_cmpxchg
#define __atomic_try_cmpxchg(type, _p, _po, _n) \
({ \
typeof(_po) __po = (_po); \
typeof(*(_po)) __r, __o = *__po; \
__r = atomic_cmpxchg##type((_p), __o, (_n)); \
if (unlikely(__r != __o)) \
*__po = __r; \
likely(__r == __o); \
})
#define atomic_try_cmpxchg(_p, _po, _n) __atomic_try_cmpxchg(, _p, _po, _n)
#define atomic_try_cmpxchg_relaxed(_p, _po, _n) __atomic_try_cmpxchg(_relaxed, _p, _po, _n)
#define atomic_try_cmpxchg_acquire(_p, _po, _n) __atomic_try_cmpxchg(_acquire, _p, _po, _n)
#define atomic_try_cmpxchg_release(_p, _po, _n) __atomic_try_cmpxchg(_release, _p, _po, _n)
#else /* atomic_try_cmpxchg */
#define atomic_try_cmpxchg_relaxed atomic_try_cmpxchg
#define atomic_try_cmpxchg_acquire atomic_try_cmpxchg
#define atomic_try_cmpxchg_release atomic_try_cmpxchg
#endif /* atomic_try_cmpxchg */
#endif /* atomic_try_cmpxchg_acquire */
#if LINUX_VERSION_IS_LESS(3,7,0)
/*
* atomic_dec_if_positive - decrement by 1 if old value positive
* @v: pointer of type atomic_t
*
* The function returns the old value of *v minus 1, even if
* the atomic variable, v, was not decremented.
*/
static inline int atomic_dec_if_positive(atomic_t *v)
{
int c, old, dec;
c = atomic_read(v);
for (;;) {
dec = c - 1;
if (unlikely(dec < 0))
break;
old = atomic_cmpxchg((v), c, dec);
if (likely(old == c))
break;
c = old;
}
return dec;
}
#endif
#endif /* __BP_ATOMIC_H */
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