One question I have regarding the feature, regarding the partial offload compatible with ndo_features_check().
Consider the following example - Let's assume my adapter is capable of doing outer-csum validation for vxlan packets, but only if inner network protocol is IPv4, while at the same time it's capable of doing gso offloading for any vxlan-encapsulated packet. In that case, I'll publish NETIF_F_GSO_UDP_TUNNEL_CSUM as part of my offload capability [& encap capabilities], and in my driver's implementation of ndo_features_check() I'd remove the feature in case I'd find out SKB is vxlan whose inner network protocol is ipv6. Is there a way I could have benefited from the partial offload in that case? If I understand the feature correctly, if I were to publish UDP_TUNNEL_CSUM under partial-gso, it would mean that stack would peel the feature off until it would decide there's actual need for SW GSO, thereby denying me the ability of utilizing the HW offload capability for CSUM. Am I reading it wrong? Or does this trade-off exist?
