08/10/2021 08:26, lihuisong (C):

As you mentioned, if we do not want the user to free rte_pci_device and 
we want rte_pci_device
to be freed in time. Can we add a code logic calculating the number of 
ports under a PCI address
and calling rte_dev_remove() in rte_eth_dev_close() to free 
rte_pci_device and delete it from rte_pci_bus?

Yes that's the idea.
But it cannot be done in ethdev lib,
it should be the responsibility of the driver.
Only the driver knows exactly what to free.