virtio-net: introduce and use helper function for guest gso support checks

Probe routine is already several hundred lines.
Use helper function for guest gso support check.

Signed-off-by: Gavin Li <gavinl@nvidia.com>
Reviewed-by: Gavi Teitz <gavi@nvidia.com>
Reviewed-by: Parav Pandit <parav@nvidia.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Reviewed-by: Si-Wei Liu <si-wei.liu@oracle.com>
Message-Id: <20220914144911.56422-2-gavinl@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Author: GavinLi-NV

drivers/net/virtio_net.c

@@ -3682,6 +3682,14 @@ static int virtnet_validate(struct virtio_device *vdev)
 	return 0;
 }
 
+static bool virtnet_check_guest_gso(const struct virtnet_info *vi)
+{
+	return virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_TSO4) ||
+		virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_TSO6) ||
+		virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_ECN) ||
+		virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_UFO);
+}
+
 static int virtnet_probe(struct virtio_device *vdev)
 {
 	int i, err = -ENOMEM;
@@ -3777,10 +3785,7 @@ static int virtnet_probe(struct virtio_device *vdev)
 	spin_lock_init(&vi->refill_lock);
 
 	/* If we can receive ANY GSO packets, we must allocate large ones. */
-	if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
-	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6) ||
-	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN) ||
-	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_UFO))
+	if (virtnet_check_guest_gso(vi))
 		vi->big_packets = true;
 
 	if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))