Looking at this: > #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 why is it optimised for '*p' being zero?? I'd have though the initial assignment to 'v' should be made by reading '*p' without any memory barriers (etc). David