vd_lbl2cksum
label->dkl_cksum = vd_lbl2cksum(label);
label->dkl_cksum != vd_lbl2cksum(label))
label->dkl_cksum = vd_lbl2cksum(label);
label.dkl_cksum != vd_lbl2cksum(&label) ||
static ushort_t vd_lbl2cksum(struct dk_label *label);