• Brenden Blanco's avatar
    net/mlx4_en: fixup xdp tx irq to match rx · 958b3d39
    Brenden Blanco authored
    In cases where the number of tx rings is not a multiple of the number of
    rx rings, the tx completion event will be handled on a different core
    from the transmit and population of the ring. Races on the ring will
    lead to a double-free of the page, and possibly other corruption.
    The rings are initialized by default with a valid multiple of rings,
    based on the number of cpus, therefore an invalid configuration requires
    ethtool to change the ring layout. For instance 'ethtool -L eth0 rx 9 tx
    8' will cause packets received on rx0, and XDP_TX'd to tx48, to be
    completed on cpu3 (48 % 9 == 3).
    Resolve this discrepancy by shifting the irq for the xdp tx queues to
    start again from 0, modulo rx_ring_num.
    Fixes: 9ecc2d86
     ("net/mlx4_en: add xdp forwarding and data write support")
    Reported-by: default avatarJesper Dangaard Brouer <brouer@redhat.com>
    Signed-off-by: default avatarBrenden Blanco <bblanco@plumgrid.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>