ulist_add_merge
return ulist_add_merge(ulist, val, aux, NULL, gfp_mask);
int ulist_add_merge(struct ulist *ulist, u64 val, u64 aux,
int ret = ulist_add_merge(ulist, val, (uintptr_t)aux, &old64, gfp_mask);
return ulist_add_merge(ulist, val, (u64)aux, (u64 *)old_aux, gfp_mask);