l2arc_vdev_present
ASSERT(!l2arc_vdev_present(vd));
pool != 0ULL && l2arc_vdev_present(vd))
pool != 0ULL && l2arc_vdev_present(vd))
boolean_t l2arc_vdev_present(vdev_t *vd);
if (l2arc_vdev_present(vd)) {