51 lines
1.1 KiB
C
51 lines
1.1 KiB
C
#ifndef _LINUX_ATOMIC_H
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#define _LINUX_ATOMIC_H
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#include <asm/atomic.h>
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/**
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* atomic_inc_not_zero_hint - increment if not null
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* @v: pointer of type atomic_t
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* @hint: probable value of the atomic before the increment
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*
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* This version of atomic_inc_not_zero() gives a hint of probable
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* value of the atomic. This helps processor to not read the memory
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* before doing the atomic read/modify/write cycle, lowering
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* number of bus transactions on some arches.
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*
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* Returns: 0 if increment was not done, 1 otherwise.
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*/
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#ifndef atomic_inc_not_zero_hint
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static inline int atomic_inc_not_zero_hint(atomic_t *v, int hint)
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{
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int val, c = hint;
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/* sanity test, should be removed by compiler if hint is a constant */
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if (!hint)
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return atomic_inc_not_zero(v);
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do {
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val = atomic_cmpxchg(v, c, c + 1);
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if (val == c)
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return 1;
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c = val;
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} while (c);
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return 0;
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}
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#endif
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#ifndef CONFIG_ARCH_HAS_ATOMIC_OR
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static inline void atomic_or(int i, atomic_t *v)
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{
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int old;
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int new;
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do {
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old = atomic_read(v);
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new = old | i;
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} while (atomic_cmpxchg(v, old, new) != old);
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}
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#endif /* #ifndef CONFIG_ARCH_HAS_ATOMIC_OR */
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#endif /* _LINUX_ATOMIC_H */
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