On 06.11.2020 02:14, Jakub Kicinski wrote:
> On Wed, 4 Nov 2020 15:25:24 +0100 Heiner Kallweit wrote:
>> @@ -1066,7 +1054,7 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb,
>> struct net_device *dev)
>> return NETDEV_TX_OK;
>>
>> drop:
>> - this_cpu_inc(tun->pcpu_stats->tx_dropped);
>> + dev->stats.tx_dropped++;
>> skb_tx_error(skb);
>> kfree_skb(skb);
>> rcu_read_unlock();
>
> This is no longer atomic. Multiple CPUs may try to update it at the
> same time.
>
> Do you know what the story on dev->rx_dropped is? The kdoc says drivers
> are not supposed to use it but:
>
> drivers/net/ipvlan/ipvlan_core.c:
> atomic_long_inc(&skb->dev->rx_dropped);
> drivers/net/macvlan.c: atomic_long_inc(&skb->dev->rx_dropped);
> drivers/net/vxlan.c: atomic_long_inc(&vxlan->dev->rx_dropped);
>
> Maybe tun can use it, too?
>
Thanks, yes that should be possible. Here we speak about tx_dropped,
but AFAICS the same applies as for rx_dropped. Will change it accordingly
in a v3.
