[PATCH net] virtio-net: enable big mode correctly
From: Jason Wang <jasowang@redhat.com>
Date: 2021-11-25 06:08:10
Also in:
lkml, virtualization
Subsystem:
networking drivers, the rest, virtio net driver · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, "Michael S. Tsirkin", Jason Wang
When VIRTIO_NET_F_MTU feature is not negotiated, we assume a very large max_mtu. In this case, using small packet mode is not correct since it may breaks the networking when MTU is grater than ETH_DATA_LEN. To have a quick fix, simply enable the big packet mode when VIRTIO_NET_F_MTU is not negotiated. We can do optimization on top. Reported-by: Eli Cohen <redacted> Cc: Eli Cohen <redacted> Signed-off-by: Jason Wang <jasowang@redhat.com> --- drivers/net/virtio_net.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 7c43bfc1ce44..83ae3ef5eb11 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c@@ -3200,11 +3200,12 @@ static int virtnet_probe(struct virtio_device *vdev) dev->mtu = mtu; dev->max_mtu = mtu; - /* TODO: size buffers correctly in this case. */ - if (dev->mtu > ETH_DATA_LEN) - vi->big_packets = true; } + /* TODO: size buffers correctly in this case. */ + if (dev->max_mtu > ETH_DATA_LEN) + vi->big_packets = true; + if (vi->any_header_sg) dev->needed_headroom = vi->hdr_len;
--
2.25.1