vdo_get_data_region_start
result = decode_layout(buffer, offset, vdo_get_data_region_start(*geometry) + 1,
vdo_get_data_region_start(*geometry) + 1,
return vdo_get_data_region_start(geometry) -
vdo_get_data_region_start(vdo->geometry),
vdo_get_data_region_start(vdo->geometry),