vxlan_core: add helper vxlan_vni_in_use

more users in follow up patches
Signed-off-by: NRoopa Prabhu <roopa@nvidia.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/vxlan/vxlan_core.c

@@ -3554,13 +3554,38 @@ static int vxlan_sock_add(struct vxlan_dev *vxlan)
 	return ret;
 }
 
+static int vxlan_vni_in_use(struct net *src_net, struct vxlan_dev *vxlan,
+			    struct vxlan_config *conf, __be32 vni)
+{
+	struct vxlan_net *vn = net_generic(src_net, vxlan_net_id);
+	struct vxlan_dev *tmp;
+
+	list_for_each_entry(tmp, &vn->vxlan_list, next) {
+		if (tmp == vxlan)
+			continue;
+		if (tmp->cfg.vni != vni)
+			continue;
+		if (tmp->cfg.dst_port != conf->dst_port)
+			continue;
+		if ((tmp->cfg.flags & (VXLAN_F_RCV_FLAGS | VXLAN_F_IPV6)) !=
+		    (conf->flags & (VXLAN_F_RCV_FLAGS | VXLAN_F_IPV6)))
+			continue;
+
+		if ((conf->flags & VXLAN_F_IPV6_LINKLOCAL) &&
+		    tmp->cfg.remote_ifindex != conf->remote_ifindex)
+			continue;
+
+		return -EEXIST;
+	}
+
+	return 0;
+}
+
 static int vxlan_config_validate(struct net *src_net, struct vxlan_config *conf,
 				 struct net_device **lower,
 				 struct vxlan_dev *old,
 				 struct netlink_ext_ack *extack)
 {
-	struct vxlan_net *vn = net_generic(src_net, vxlan_net_id);
-	struct vxlan_dev *tmp;
 	bool use_ipv6 = false;
 
 	if (conf->flags & VXLAN_F_GPE) {
@@ -3693,22 +3718,7 @@ static int vxlan_config_validate(struct net *src_net, struct vxlan_config *conf,
 	if (!conf->age_interval)
 		conf->age_interval = FDB_AGE_DEFAULT;
 
-	list_for_each_entry(tmp, &vn->vxlan_list, next) {
-		if (tmp == old)
-			continue;
-
-		if (tmp->cfg.vni != conf->vni)
-			continue;
-		if (tmp->cfg.dst_port != conf->dst_port)
-			continue;
-		if ((tmp->cfg.flags & (VXLAN_F_RCV_FLAGS | VXLAN_F_IPV6)) !=
-		    (conf->flags & (VXLAN_F_RCV_FLAGS | VXLAN_F_IPV6)))
-			continue;
-
-		if ((conf->flags & VXLAN_F_IPV6_LINKLOCAL) &&
-		    tmp->cfg.remote_ifindex != conf->remote_ifindex)
-			continue;
-
+	if (vxlan_vni_in_use(src_net, old, conf, conf->vni)) {
 		NL_SET_ERR_MSG(extack,
 			       "A VXLAN device with the specified VNI already exists");
 		return -EEXIST;