• Davide Caratti's avatar
    net: vlan: add support for tunnel offload · 7dad9937
    Davide Caratti authored
    GSO tunneled packets are always segmented in software before they are
    transmitted by a VLAN, even when the lower device can offload tunnel
    encapsulation and VLAN together (i.e., some bits in NETIF_F_GSO_ENCAP_ALL
    mask are set in the lower device 'vlan_features'). If we let VLANs have
    the same tunnel offload capabilities as their lower device, throughput
    can improve significantly when CPU is limited on the transmitter side.
    
     - set NETIF_F_GSO_ENCAP_ALL bits in the VLAN 'hw_features', to ensure
     that 'features' will have those bits zeroed only when the lower device
     has no hardware support for tunnel encapsulation.
     - for the same reason, copy GSO-related bits of 'hw_enc_features' from
     lower device to VLAN, and ensure to update that value when the lower
     device changes its features.
     - set NETIF_F_HW_CSUM bit in the VLAN 'hw_enc_features' if 'real_dev'
     is able to compute checksums at least for a kind of packets, like done
     with commit 8403debe ("vlan: Keep NETIF_F_HW_CSUM similar to other
     software devices"). This avoids software segmentation due to mismatching
     checksum capabilities between VLAN's 'features' and 'hw_enc_features'.
    Reported-by: default avatarFlavio Leitner <fbl@redhat.com>
    Signed-off-by: default avatarDavide Caratti <dcaratti@redhat.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    7dad9937
vlan.c 19.6 KB