On Tue, Sep 29, 2020 at 2:23 PM Michael S. Tsirkin [off-list ref] wrote:

On Tue, Sep 29, 2020 at 09:58:06AM +0800, xiangxia.m.yue@gmail.com wrote:

quoted

From: Tonghao Zhang <redacted>

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 <redacted>
---
v2:
* change the fix-tag
---
 drivers/net/virtio_net.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 7145c83c6c8c..21b71148c532 100644
--- 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))
+

I think I'd rather we open-coded this, the macro is only
used in one place ...

Yes, in this patch, it is used only in one place. But in next patch
[1], we use it twice and that make the code look a bit nicer.
Would we open-coded this in this patch ?

[1] - http://patchwork.ozlabs.org/project/netdev/patch/20200928033915.82810-2-xiangxia.m.yue@gmail.com/

quoted

 struct virtnet_stat_desc {
      char desc[ETH_GSTRING_LEN];
      size_t offset;

@@ -2531,7 +2536,8 @@ 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)

quoted

--
2.23.0

-- 
Best regards, Tonghao