On Fri, Dec 8, 2017 at 10:27 PM, Michael Chan <michael.c...@broadcom.com> wrote:
> Hardware should not aggregate any packets when generic XDP is installed.
>
> Cc: Ariel Elior <ariel.el...@cavium.com>
> Cc: everest-linux...@cavium.com
> Signed-off-by: Michael Chan <michael.c...@broadcom.com>
> ---
> net/core/dev.c | 24 ++++++++++++++++++++++++
> 1 file changed, 24 insertions(+)
>
> diff --git a/net/core/dev.c b/net/core/dev.c
> index 6ebd0e7..ec08ace 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -1542,6 +1542,29 @@ void dev_disable_lro(struct net_device *dev)
> }
> EXPORT_SYMBOL(dev_disable_lro);
>
> +/**
> + * dev_disable_gro_hw - disable HW Generic Receive Offload on a device
> + * @dev: device
> + *
> + * Disable HW Generic Receive Offload (GRO_HW) on a net device. Must be
> + * called under RTNL. This is needed if Generic XDP is installed on
> + * the device.
> + */
> +static void dev_disable_gro_hw(struct net_device *dev)
> +{
> + struct net_device *lower_dev;
> + struct list_head *iter;
> +
> + dev->wanted_features &= ~NETIF_F_GRO_HW;
> + netdev_update_features(dev);
> +
> + if (unlikely(dev->features & NETIF_F_GRO_HW))
> + netdev_WARN(dev, "failed to disable GRO_HW!\n");
> +
> + netdev_for_each_lower_dev(dev, lower_dev, iter)
> + dev_disable_gro_hw(lower_dev);
I think these two lines are redundant in dev_disable_lro, since
netdev_update_features should propagate the disable to all of the
lower devices. Also this doesn't prevent the lower devices from
re-enabling gro_hw.
> +}
> +
> static int call_netdevice_notifier(struct notifier_block *nb, unsigned long
> val,
> struct net_device *dev)
> {
> @@ -4564,6 +4587,7 @@ static int generic_xdp_install(struct net_device *dev,
> struct netdev_bpf *xdp)
> } else if (new && !old) {
> static_key_slow_inc(&generic_xdp_needed);
> dev_disable_lro(dev);
> + dev_disable_gro_hw(dev);
> }
> break;
>
> --
> 1.8.3.1
>
