netdev - Re: [PATCH v3 net-next 2/3] openvswitch: Use is_skb

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Message-ID: <CAOrHB_BEQBbvDa2W0dJmmANsjZEiwx7GbTxo-7yirDB=5d9cqQ@mail.gmail.com>
Date:   Thu, 1 Dec 2016 11:50:00 -0800
From:   Pravin Shelar <pshelar@....org>
To:     Jiri Benc <jbenc@...hat.com>
Cc:     Jarno Rajahalme <jarno@....org>,
        Linux Kernel Network Developers <netdev@...r.kernel.org>,
        Eric Garver <e@...g.me>
Subject: Re: [PATCH v3 net-next 2/3] openvswitch: Use is_skb_forwardable() for
 length check.

On Wed, Nov 30, 2016 at 5:51 AM, Jiri Benc <jbenc@...hat.com> wrote:
> On Tue, 29 Nov 2016 15:30:52 -0800, Jarno Rajahalme wrote:
>> @@ -504,11 +485,20 @@ void ovs_vport_send(struct vport *vport, struct sk_buff *skb, u8 mac_proto)
>>               goto drop;
>>       }
>>
>> -     if (unlikely(packet_length(skb, vport->dev) > mtu &&
>> -                  !skb_is_gso(skb))) {
>> -             net_warn_ratelimited("%s: dropped over-mtu packet: %d > %d\n",
>> -                                  vport->dev->name,
>> -                                  packet_length(skb, vport->dev), mtu);
>> +     if (unlikely(!is_skb_forwardable(vport->dev, skb))) {
>
> How does this work when the vlan tag is accelerated? Then we can be
> over MTU, yet the check will pass.
>

This is not changing any behavior compared to current OVS vlan checks.
Single vlan header is not considered for MTU check.