Re: [net PATCH v3 3/5] virtio_net: factor out xdp handler for readability

John Fastabend
2017-01-13T19:57:11Z

On 17-01-12 11:40 PM, Jason Wang wrote:
>
>
> On 2017年01月13日 10:51, John Fastabend wrote:
>> At this point the do_xdp_prog is mostly if/else branches handling
>> the different modes of virtio_net. So remove it and handle running
>> the program in the per mode handlers.
>>
>> Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
>> ---
>> drivers/net/virtio_net.c | 76 +++++++++++++++++-----------------------------
>> 1 file changed, 28 insertions(+), 48 deletions(-)
>>
>> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
>> index 43cb2e0..ec54644 100644
>> --- a/drivers/net/virtio_net.c
>> +++ b/drivers/net/virtio_net.c
>> @@ -388,49 +388,6 @@ static void virtnet_xdp_xmit(struct virtnet_info *vi,
>> virtqueue_kick(sq->vq);
>> }
>>
>
> [...]
>
>> /* This happens when rx buffer size is underestimated */
>> @@ -598,8 +570,10 @@ static struct sk_buff *receive_mergeable(struct
>> net_device *dev,
>> if (unlikely(hdr->hdr.gso_type))
>> goto err_xdp;
>> - act = do_xdp_prog(vi, rq, xdp_prog,
>> - page_address(xdp_page) + offset, len);
>> + data = page_address(xdp_page) + offset;
>> + xdp.data = data + desc_room;
>> + xdp.data_end = xdp.data + (len - vi->hdr_len);
>
> It looks desc_room is always vi->hdr_len.
>

Seems to be the case I'll just use vi->hdr_len and remove the variable.

Thanks.

>> + act = bpf_prog_run_xdp(xdp_prog, &xdp);
>> switch (act) {
>> case XDP_PASS:
>> /* We can only create skb based on xdp_page. */
>> @@ -613,13 +587,19 @@ static struct sk_buff *receive_mergeable(struct
>> net_device *dev,
>> }
>> break;
>> case XDP_TX:
>> + qp = vi->curr_queue_pairs -
>> + vi->xdp_queue_pairs +
>> + smp_processor_id();
>> + virtnet_xdp_xmit(vi, rq, &vi->sq[qp], &xdp, data);
>> ewma_pkt_len_add(&rq->mrg_avg_pkt_len, len);
>> if (unlikely(xdp_page != page))
>> goto err_xdp;
>> rcu_read_unlock();
>> goto xdp_xmit;
>> - case XDP_DROP:
>> default:
>> + bpf_warn_invalid_xdp_action(act);
>> + case XDP_ABORTED:
>> + case XDP_DROP:
>> if (unlikely(xdp_page != page))
>> __free_pages(xdp_page, 0);
>> ewma_pkt_len_add(&rq->mrg_avg_pkt_len, len);
>>
>