inside of the net_device structure, I know I can take
the net_device pointer as documented in [3], but how may I obtain the
napi_struct from the netdevice? or I am doing it the wrong way?
You are doing it the wrong way. The napi_struct you need is not embedded
here. See
$ less +/napi drivers/net/ethernet/realtek/8139cp.c
(first match in struct cp_private).
You should really read one of the existing drivers.
--
Ueimor