bridge: Reorder neighbor suppression check when flooding

The bridge does not flood ARP / NS packets for which a reply was sent to
bridge ports that have neighbor suppression enabled.

Subsequent patches are going to add per-{Port, VLAN} neighbor
suppression, which is going to make it more expensive to check whether
neighbor suppression is enabled since a VLAN lookup will be required.

Therefore, instead of unnecessarily performing this lookup for every
packet, only perform it for ARP / NS packets for which a reply was sent.
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/bridge/br_forward.c

@@ -224,8 +224,8 @@ void br_flood(struct net_bridge *br, struct sk_buff *skb,
 		/* Do not flood to ports that enable proxy ARP */
 		if (p->flags & BR_PROXYARP)
 			continue;
-		if ((p->flags & (BR_PROXYARP_WIFI | BR_NEIGH_SUPPRESS)) &&
-		    BR_INPUT_SKB_CB(skb)->proxyarp_replied)
+		if (BR_INPUT_SKB_CB(skb)->proxyarp_replied &&
+		    (p->flags & (BR_PROXYARP_WIFI | BR_NEIGH_SUPPRESS)))
 			continue;
 
 		prev = maybe_deliver(prev, p, skb, local_orig);