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[79.178.2.214]) by smtp.gmail.com with ESMTPSA id s19sm5973078qkj.88.2020.02.25.03.18.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 25 Feb 2020 03:18:08 -0800 (PST) Date: Tue, 25 Feb 2020 06:18:01 -0500 From: "Michael S. Tsirkin" To: Yuya Kusakabe Cc: jasowang@redhat.com, andriin@fb.com, ast@kernel.org, bpf@vger.kernel.org, daniel@iogearbox.net, davem@davemloft.net, hawk@kernel.org, john.fastabend@gmail.com, kafai@fb.com, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, songliubraving@fb.com, yhs@fb.com Subject: Re: [PATCH bpf-next v6 1/2] virtio_net: keep vnet header zeroed if XDP is loaded for small buffer Message-ID: <20200225061501-mutt-send-email-mst@kernel.org> References: <20200225033103.437305-1-yuya.kusakabe@gmail.com> <20200225033212.437563-1-yuya.kusakabe@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200225033212.437563-1-yuya.kusakabe@gmail.com> Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Tue, Feb 25, 2020 at 12:32:11PM +0900, Yuya Kusakabe wrote: > We do not want to care about the vnet header in receive_small() if XDP > is loaded, since we can not know whether or not the packet is modified > by XDP. > > Fixes: f6b10209b90d ("virtio-net: switch to use build_skb() for small buffer") > Signed-off-by: Yuya Kusakabe Acked-by: Michael S. Tsirkin > --- > drivers/net/virtio_net.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index 2fe7a3188282..f39d0218bdaa 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -735,10 +735,10 @@ static struct sk_buff *receive_small(struct net_device *dev, > } > skb_reserve(skb, headroom - delta); > skb_put(skb, len); > - if (!delta) { > + if (!xdp_prog) { > buf += header_offset; > memcpy(skb_vnet_hdr(skb), buf, vi->hdr_len); > - } /* keep zeroed vnet hdr since packet was changed by bpf */ > + } /* keep zeroed vnet hdr since XDP is loaded */ > > err: > return skb; > -- > 2.24.1