• Vladimir Oltean's avatar
    Revert "net: dsa: sja1105: Clear VLAN filtering offload netdev feature" · a1e6f641
    Vladimir Oltean authored
    This reverts commit e9bf9694.
    
    The topic of the reverted patch is the support for switches with global
    VLAN filtering, added by commit 061f6a50 ("net: dsa: Add
    ndo_vlan_rx_{add, kill}_vid implementation"). Be there a switch with 4
    ports swp0 -> swp3, and the following setup:
    
    ip link add br0 type bridge vlan_filtering 1
    ip link set swp0 master br0
    ip link set swp1 master br0
    
    What would happen with VLAN-tagged traffic received on standalone ports
    swp2 and swp3? Well, it would get dropped, were it not for the
    .ndo_vlan_rx_add_vid and .ndo_vlan_rx_kill_vid implementations (called
    from vlan_vid_add and vlan_vid_del respectively). Basically, for DSA
    switches where VLAN filtering is a global attribute, we enforce the
    standalone ports to have 'rx-vlan-filter: off [fixed]' in their ethtool
    features, which lets the user know that all VLAN-tagged packets that are
    not explicitly added in the RX filtering list are dropped.
    
    As for the sja1105 driver, at the time of the reverted patch, it was
    operating in a pretty handicapped mode when it had ports under a bridge
    with vlan_filtering=1. Specifically, it was unable to terminate traffic
    through the CPU port (for further explanation see "Traffic support" in
    Documentation/networking/dsa/sja1105.rst).
    
    However, since then, the sja1105 driver has made considerable progress,
    and that limitation is no longer as severe now. Specifically, since
    commit 2cafa72e ("net: dsa: sja1105: add a new
    best_effort_vlan_filtering devlink parameter"), the driver is able to
    perform CPU termination even when some ports are under bridges with
    vlan_filtering=1. Then, since commit 8841f6e6 ("net: dsa: sja1105:
    make devlink property best_effort_vlan_filtering true by default"), this
    even became the default operating mode.
    
    So we can now take advantage of the logic in the DSA core.
    Signed-off-by: default avatarVladimir Oltean <vladimir.oltean@nxp.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    a1e6f641
sja1105_main.c 103 KB