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References: <20211216031135.3182660-1-wangwenliang.1995@bytedance.com>
In-Reply-To: <20211216031135.3182660-1-wangwenliang.1995@bytedance.com>
From:   Jason Wang <jasowang@redhat.com>
Date:   Thu, 16 Dec 2021 11:23:42 +0800
Message-ID: <CACGkMEtPkybSyPRXqcqtBGbEHvMEw04dcWpUDswuXgwEnshBSA@mail.gmail.com>
Subject: Re: [PATCH] virtio_net: fix rx_drops stat for small pkts
To:     Wenliang Wang <wangwenliang.1995@bytedance.com>
Cc:     mst <mst@redhat.com>, davem <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        virtualization <virtualization@lists.linux-foundation.org>,
        netdev <netdev@vger.kernel.org>,
        linux-kernel <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Thu, Dec 16, 2021 at 11:12 AM Wenliang Wang
<wangwenliang.1995@bytedance.com> wrote:
>
> We found the stat of rx drops for small pkts does not increment when
> build_skb fail, it's not coherent with other mode's rx drops stat.
>
> Signed-off-by: Wenliang Wang <wangwenliang.1995@bytedance.com>

Acked-by: Jason Wang <jasowang@redhat.com>

> ---
>  drivers/net/virtio_net.c | 9 +++------
>  1 file changed, 3 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 55db6a336f7e..b107835242ad 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -733,7 +733,7 @@ static struct sk_buff *receive_small(struct net_device *dev,
>                 pr_debug("%s: rx error: len %u exceeds max size %d\n",
>                          dev->name, len, GOOD_PACKET_LEN);
>                 dev->stats.rx_length_errors++;
> -               goto err_len;
> +               goto err;
>         }
>
>         if (likely(!vi->xdp_enabled)) {
> @@ -825,10 +825,8 @@ static struct sk_buff *receive_small(struct net_device *dev,
>
>  skip_xdp:
>         skb = build_skb(buf, buflen);
> -       if (!skb) {
> -               put_page(page);
> +       if (!skb)
>                 goto err;
> -       }
>         skb_reserve(skb, headroom - delta);
>         skb_put(skb, len);
>         if (!xdp_prog) {
> @@ -839,13 +837,12 @@ static struct sk_buff *receive_small(struct net_device *dev,
>         if (metasize)
>                 skb_metadata_set(skb, metasize);
>
> -err:
>         return skb;
>
>  err_xdp:
>         rcu_read_unlock();
>         stats->xdp_drops++;
> -err_len:
> +err:
>         stats->drops++;
>         put_page(page);
>  xdp_xmit:
> --
> 2.30.2
>