pgnr_to_size
if ((start + pgnr_to_size(pgnr)) != end) {
new_bo->end = new_bo->start + pgnr_to_size(pgnr);
bdev->size = pgnr_to_size(bdev->pgnr);
bo->end = bo->start + pgnr_to_size(pgnr);
virt += pgnr_to_size(1);
virt += pgnr_to_size(1);