nfp: flower: fixup ipv6/ipv4 route lookup for neigh events

When a callback is received to invalidate a neighbour entry
there is no need to try and populate any other flow information.
Only the flowX->daddr information is needed as lookup key to delete
an entry from the NFP neighbour table. Fix this by only doing the
lookup if the callback is for a new entry.

As part of this cleanup remove the setting of flow6.flowi6_proto, as
this is not needed either, it looks to be a possible leftover from a
previous implementation.
Signed-off-by: Louis Peens <louis.peens@corigine.com>
Signed-off-by: Yinjun Zhang <yinjun.zhang@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/netronome/nfp/flower/tunnel_conf.c

@@ -494,7 +494,7 @@ nfp_tun_neigh_event_handler(struct notifier_block *nb, unsigned long event,
 	struct flowi6 flow6 = {};
 	struct neighbour *n;
 	struct nfp_app *app;
-	struct rtable *rt;
+	bool neigh_invalid;
 	bool ipv6 = false;
 	int err;
 
@@ -513,6 +513,8 @@ nfp_tun_neigh_event_handler(struct notifier_block *nb, unsigned long event,
 	if (n->tbl->family == AF_INET6)
 		ipv6 = true;
 
+	neigh_invalid = !(n->nud_state & NUD_VALID) || n->dead;
+
 	if (ipv6)
 		flow6.daddr = *(struct in6_addr *)n->primary_key;
 	else
@@ -533,29 +535,41 @@ nfp_tun_neigh_event_handler(struct notifier_block *nb, unsigned long event,
 #if IS_ENABLED(CONFIG_INET)
 	if (ipv6) {
 #if IS_ENABLED(CONFIG_IPV6)
+		if (!neigh_invalid) {
 			struct dst_entry *dst;
-
-		dst = ipv6_stub->ipv6_dst_lookup_flow(dev_net(n->dev), NULL,
+			/* Use ipv6_dst_lookup_flow to populate flow6->saddr
+			 * and other fields. This information is only needed
+			 * for new entries, lookup can be skipped when an entry
+			 * gets invalidated - as only the daddr is needed for
+			 * deleting.
+			 */
+			dst = ip6_dst_lookup_flow(dev_net(n->dev), NULL,
 						  &flow6, NULL);
 			if (IS_ERR(dst))
 				return NOTIFY_DONE;
 
 			dst_release(dst);
-		flow6.flowi6_proto = IPPROTO_UDP;
+		}
 		nfp_tun_write_neigh_v6(n->dev, app, &flow6, n, GFP_ATOMIC);
 #else
 		return NOTIFY_DONE;
 #endif /* CONFIG_IPV6 */
 	} else {
-		/* Do a route lookup to populate flow data. */
+		if (!neigh_invalid) {
+			struct rtable *rt;
+			/* Use ip_route_output_key to populate flow4->saddr and
+			 * other fields. This information is only needed for
+			 * new entries, lookup can be skipped when an entry
+			 * gets invalidated - as only the daddr is needed for
+			 * deleting.
+			 */
 			rt = ip_route_output_key(dev_net(n->dev), &flow4);
 			err = PTR_ERR_OR_ZERO(rt);
 			if (err)
 				return NOTIFY_DONE;
 
 			ip_rt_put(rt);
-
-		flow4.flowi4_proto = IPPROTO_UDP;
+		}
 		nfp_tun_write_neigh_v4(n->dev, app, &flow4, n, GFP_ATOMIC);
 	}
 #else