On Sat, Dec 9, 2017 at 10:56 AM, Alexander Duyck
<alexander.du...@gmail.com> wrote:
> 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.
Right. But for GRO_HW, there is no automatic propagation.
> Also this doesn't prevent the lower devices from
> re-enabling gro_hw.
Right. You can re-enable LRO on the upper device as well.
