virtio-net: don't disable guest csum when disable LRO

[ Upstream commit 1a03b8a35a957f9f38ecb8a97443b7380bbf6a8b ]

Open vSwitch and Linux bridge will disable LRO of the interface
when this interface added to them. Now when disable the LRO, the
virtio-net csum is disable too. That drops the forwarding performance.

Fixes: a02e8964eaf9 ("virtio-net: ethtool configurable LRO")
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index ba38765dc4905aa9c461fb49e75a47e6440f81ec..c34927b1d806efb94a4e012d38b11727c532c4c1 100644 (file)
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -63,6 +63,11 @@ static const unsigned long guest_offloads[] = {
        VIRTIO_NET_F_GUEST_CSUM
 };
 
+#define GUEST_OFFLOAD_LRO_MASK ((1ULL << VIRTIO_NET_F_GUEST_TSO4) | \
+                               (1ULL << VIRTIO_NET_F_GUEST_TSO6) | \
+                               (1ULL << VIRTIO_NET_F_GUEST_ECN)  | \
+                               (1ULL << VIRTIO_NET_F_GUEST_UFO))
+
 struct virtnet_stat_desc {
        char desc[ETH_GSTRING_LEN];
        size_t offset;
@@ -2547,7 +2552,8 @@ static int virtnet_set_features(struct net_device *dev,
                if (features & NETIF_F_LRO)
                        offloads = vi->guest_offloads_capable;
                else
-                       offloads = 0;
+                       offloads = vi->guest_offloads_capable &
+                                  ~GUEST_OFFLOAD_LRO_MASK;
 
                err = virtnet_set_guest_offloads(vi, offloads);
                if (err)