Linux Virtualization - Jan 2021 - [PATCH net-next v2 2/7] virtio-net, xsk: distinguish XDP_TX and XSK XMIT ctx

On 2021/1/18 ??7:54, Xuan Zhuo wrote:
> On Mon, 18 Jan 2021 14:45:16 +0800, Jason Wang <jasowang at
redhat.com> wrote:
>> On 2021/1/16 ??10:59, Xuan Zhuo wrote:
>>> If support xsk, a new ptr will be recovered during the
>>> process of freeing the old ptr. In order to distinguish between ctx
sent
>>> by XDP_TX and ctx sent by xsk, a struct is added here to
distinguish
>>> between these two situations. virtnet_xdp_type.type It is used to
>>> distinguish different ctx, and virtnet_xdp_type.offset is used to
record
>>> the offset between "true ctx" and virtnet_xdp_type.
>>>
>>> The newly added virtnet_xsk_hdr will be used for xsk.
>>>
>>> Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
>>
>> Any reason that you can't simply encode the type in the pointer
itself
>> as we used to do?
>>
>> #define VIRTIO_XSK_FLAG??? BIT(1)
>>
>> ?
> Since xdp socket does not use xdp_frame, we will encounter three data types
when
> recycling: skb, xdp_frame, xdp socket.

Just to make sure we are in the same page. Currently, the pointer type 
is encoded with 1 bit in the pointer. Can we simply use 2 bit to 
distinguish skb, xdp, xsk?

Thanks

>