This patchset implements asynchronous crypto handling in the layer 2 TX path. With this we can allow IPsec ESP GSO for software crypto. This also merges the IPsec GSO and non-GSO paths to both use validate_xmit_xfrm().
1) Separate ESP handling from segmentation for GRO packets. This unifies the IPsec GSO and non GSO codepath. 2) Add asynchronous callbacks for xfrm on layer 2. This adds the necessary infrastructure to core networking. 3) Allow to use the layer2 IPsec GSO codepath for software crypto, all infrastructure is there now. 4) Also allow IPsec GSO with software crypto for local sockets. 5) Don't require synchronous crypto fallback on IPsec offloading, it is not needed anymore.
