Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [RFC net-next] udp: add a GSO type for UDPv6
To:     Willem de Bruijn <willemdebruijn.kernel@gmail.com>
CC:     David Miller <davem@davemloft.net>,
        Network Development <netdev@vger.kernel.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        <salil.mehta@huawei.com>, <yisen.zhuang@huawei.com>,
        <linuxarm@huawei.com>, Jakub Kicinski <kuba@kernel.org>
References: <1599048911-7923-1-git-send-email-tanhuazhong@huawei.com>
 <CA+FuTSc_KOZRTdh34Vw3gTCzGMmi5XvDZKjpWMOXw7aby53wqw@mail.gmail.com>
From:   tanhuazhong <tanhuazhong@huawei.com>
Message-ID: <b4bf766c-4d56-cf6b-9018-468ebcd3e147@huawei.com>
Date:   Thu, 3 Sep 2020 09:25:39 +0800
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101
 Thunderbird/52.5.2
MIME-Version: 1.0
In-Reply-To: <CA+FuTSc_KOZRTdh34Vw3gTCzGMmi5XvDZKjpWMOXw7aby53wqw@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk


On 2020/9/2 22:33, Willem de Bruijn wrote:
> On Wed, Sep 2, 2020 at 2:18 PM Huazhong Tan <tanhuazhong@huawei.com> wrote:
>>
>> In some cases, for UDP GSO, UDPv4 and UDPv6 need to be handled
>> separately, for example, checksum offload, so add new GSO type
>> SKB_GSO_UDPV6_L4 for UDPv6, and the old SKB_GSO_UDP_L4 stands
>> for UDPv4.
> 
> This is in preparation for hardware you have that actually cares about
> this distinction, I guess?
> 

it is mainly for separating checksum offload of IPv4 and IPv6 right now.
with this patch, the user can switch checksum offload of IPv4 and not
affect IPv6's, vice versa.

> 
>> diff --git a/include/linux/netdev_features.h b/include/linux/netdev_features.h
>> index 2cc3cf8..b7c1a76 100644
>> --- a/include/linux/netdev_features.h
>> +++ b/include/linux/netdev_features.h
>> @@ -54,6 +54,7 @@ enum {
>>          NETIF_F_GSO_UDP_BIT,            /* ... UFO, deprecated except tuntap */
>>          NETIF_F_GSO_UDP_L4_BIT,         /* ... UDP payload GSO (not UFO) */
>>          NETIF_F_GSO_FRAGLIST_BIT,               /* ... Fraglist GSO */
>> +       NETIF_F_GSO_UDPV6_L4_BIT,       /* ... UDPv6 payload GSO (not UFO) */
>>          /**/NETIF_F_GSO_LAST =          /* last bit, see GSO_MASK */
>>                  NETIF_F_GSO_FRAGLIST_BIT,
> 
> Need to update NETIF_F_GSO_LAST then, too.

ok, thanks.

> 
>