unique_t
unique_t *un;
kmem_free(un, sizeof (unique_t));
const unique_t *una = (const unique_t *)a;
const unique_t *unb = (const unique_t *)b;
sizeof (unique_t), offsetof(unique_t, un_link));
unique_t *un = kmem_alloc(sizeof (unique_t), KM_SLEEP);
unique_t un_tofind;