[RFC PATCH 3/4] net:openvswitch: Avoid extra copy if no listeners.

[Adrian Moreno <amorenoz@redhat.com>]

If there are no listeneres in the multicast group, there is no need for
building the upcall packet. Exit early in that case.

Signed-off-by: Adrian Moreno <amorenoz@redhat.com>
---
 net/openvswitch/datapath.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
index 5a2c0b3b4112..5171aefa6a7c 100644
--- a/net/openvswitch/datapath.c
+++ b/net/openvswitch/datapath.c
@@ -455,6 +455,10 @@ static int queue_userspace_packet(struct datapath *dp, struct sk_buff *skb,
 	if (!dp_ifindex)
 		return -ENODEV;
 
+	if (upcall_info->portid == MCAST_PID &&
+	    !genl_has_listeners(&dp_packet_genl_family, ovs_dp_get_net(dp), 0))
+		return 0;
+
 	if (skb_vlan_tag_present(skb)) {
 		nskb = skb_clone(skb, GFP_ATOMIC);
 		if (!nskb)
-- 
2.44.0