Re: [PATCH stable 2/2] virtio-net: make all RX paths handle erors consistently

[Zhi Yong Wu <zwu.kernel@gmail.com>]

typo in the subject....

s/erors/errors/

On Wed, Dec 25, 2013 at 10:56 PM, Michael S. Tsirkin <mst@redhat.com> wrote:
> receive mergeable now handles errors internally.
> Do same for big and small packet paths, otherwise
> the logic is too hard to follow.
>
> Cc: Jason Wang <jasowang@redhat.com>
> Cc: David S. Miller <davem@davemloft.net>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
>
> (cherry picked from commit f121159d72091f25afb22007c833e60a6845e912)
> ---
>  drivers/net/virtio_net.c | 56 +++++++++++++++++++++++++++++++-----------------
>  1 file changed, 36 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 435076f..c0ed6d5 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -297,6 +297,34 @@ static struct sk_buff *page_to_skb(struct receive_queue *rq,
>         return skb;
>  }
>
> +static struct sk_buff *receive_small(void *buf, unsigned int len)
> +{
> +       struct sk_buff * skb = buf;
> +
> +       len -= sizeof(struct virtio_net_hdr);
> +       skb_trim(skb, len);
> +
> +       return skb;
> +}
> +
> +static struct sk_buff *receive_big(struct net_device *dev,
> +                                  struct receive_queue *rq,
> +                                  void *buf)
> +{
> +       struct page *page = buf;
> +       struct sk_buff *skb = page_to_skb(rq, page, 0);
> +
> +       if (unlikely(!skb))
> +               goto err;
> +
> +       return skb;
> +
> +err:
> +       dev->stats.rx_dropped++;
> +       give_pages(rq, page);
> +       return NULL;
> +}
> +
>  static struct sk_buff *receive_mergeable(struct net_device *dev,
>                                          struct receive_queue *rq,
>                                          void *buf,
> @@ -360,7 +388,6 @@ static void receive_buf(struct receive_queue *rq, void *buf, unsigned int len)
>         struct net_device *dev = vi->dev;
>         struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
>         struct sk_buff *skb;
> -       struct page *page;
>         struct skb_vnet_hdr *hdr;
>
>         if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
> @@ -372,26 +399,15 @@ static void receive_buf(struct receive_queue *rq, void *buf, unsigned int len)
>                         dev_kfree_skb(buf);
>                 return;
>         }
> +       if (vi->mergeable_rx_bufs)
> +               skb = receive_mergeable(dev, rq, buf, len);
> +       else if (vi->big_packets)
> +               skb = receive_big(dev, rq, buf);
> +       else
> +               skb = receive_small(buf, len);
>
> -       if (!vi->mergeable_rx_bufs && !vi->big_packets) {
> -               skb = buf;
> -               len -= sizeof(struct virtio_net_hdr);
> -               skb_trim(skb, len);
> -       } else {
> -               page = buf;
> -               if (vi->mergeable_rx_bufs) {
> -                       skb = receive_mergeable(dev, rq, page, len);
> -                       if (unlikely(!skb))
> -                               return;
> -               } else {
> -                       skb = page_to_skb(rq, page, len);
> -                       if (unlikely(!skb)) {
> -                               dev->stats.rx_dropped++;
> -                               give_pages(rq, page);
> -                               return;
> -                       }
> -               }
> -       }
> +       if (unlikely(!skb))
> +               return;
>
>         hdr = skb_vnet_hdr(skb);
>
> --
> MST
>
> _______________________________________________
> Virtualization mailing list
> Virtualization@lists.linux-foundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/virtualization



-- 
Regards,

Zhi Yong Wu