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