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- /* Atomic operations usable in machine independent code */
- #ifndef _LINUX_ATOMIC_H
- #define _LINUX_ATOMIC_H
- #include <asm/atomic.h>
- /**
- * atomic_add_unless - add unless the number is already a given value
- * @v: pointer of type atomic_t
- * @a: the amount to add to v...
- * @u: ...unless v is equal to u.
- *
- * Atomically adds @a to @v, so long as @v was not already @u.
- * Returns non-zero if @v was not @u, and zero otherwise.
- */
- static inline int atomic_add_unless(atomic_t *v, int a, int u)
- {
- return __atomic_add_unless(v, a, u) != u;
- }
- /**
- * atomic_inc_not_zero - increment unless the number is zero
- * @v: pointer of type atomic_t
- *
- * Atomically increments @v by 1, so long as @v is non-zero.
- * Returns non-zero if @v was non-zero, and zero otherwise.
- */
- #ifndef atomic_inc_not_zero
- #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
- #endif
- /**
- * atomic_inc_not_zero_hint - increment if not null
- * @v: pointer of type atomic_t
- * @hint: probable value of the atomic before the increment
- *
- * This version of atomic_inc_not_zero() gives a hint of probable
- * value of the atomic. This helps processor to not read the memory
- * before doing the atomic read/modify/write cycle, lowering
- * number of bus transactions on some arches.
- *
- * Returns: 0 if increment was not done, 1 otherwise.
- */
- #ifndef atomic_inc_not_zero_hint
- static inline int atomic_inc_not_zero_hint(atomic_t *v, int hint)
- {
- int val, c = hint;
- /* sanity test, should be removed by compiler if hint is a constant */
- if (!hint)
- return atomic_inc_not_zero(v);
- do {
- val = atomic_cmpxchg(v, c, c + 1);
- if (val == c)
- return 1;
- c = val;
- } while (c);
- return 0;
- }
- #endif
- #ifndef atomic_inc_unless_negative
- static inline int atomic_inc_unless_negative(atomic_t *p)
- {
- int v, v1;
- for (v = 0; v >= 0; v = v1) {
- v1 = atomic_cmpxchg(p, v, v + 1);
- if (likely(v1 == v))
- return 1;
- }
- return 0;
- }
- #endif
- #ifndef atomic_dec_unless_positive
- static inline int atomic_dec_unless_positive(atomic_t *p)
- {
- int v, v1;
- for (v = 0; v <= 0; v = v1) {
- v1 = atomic_cmpxchg(p, v, v - 1);
- if (likely(v1 == v))
- return 1;
- }
- return 0;
- }
- #endif
- #ifndef CONFIG_ARCH_HAS_ATOMIC_OR
- static inline void atomic_or(int i, atomic_t *v)
- {
- int old;
- int new;
- do {
- old = atomic_read(v);
- new = old | i;
- } while (atomic_cmpxchg(v, old, new) != old);
- }
- #endif /* #ifndef CONFIG_ARCH_HAS_ATOMIC_OR */
- #include <asm-generic/atomic-long.h>
- #ifdef CONFIG_GENERIC_ATOMIC64
- #include <asm-generic/atomic64.h>
- #endif
- #endif /* _LINUX_ATOMIC_H */
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