ipvs: batch __ip_vs_dev_cleanup

It's better to batch __ip_vs_cleanup to speedup ipvs
devices dismantle.
Signed-off-by: Haishuang Yan <yanhaishuang@cmss.chinamobile.com>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>

net/netfilter/ipvs/ip_vs_core.c

@@ -2433,14 +2433,19 @@ static int __net_init __ip_vs_dev_init(struct net *net)
 	return ret;
 }
 
-static void __net_exit __ip_vs_dev_cleanup(struct net *net)
+static void __net_exit __ip_vs_dev_cleanup_batch(struct list_head *net_list)
 {
-	struct netns_ipvs *ipvs = net_ipvs(net);
+	struct netns_ipvs *ipvs;
+	struct net *net;
+
 	EnterFunction(2);
+	list_for_each_entry(net, net_list, exit_list) {
+		ipvs = net_ipvs(net);
 		nf_unregister_net_hooks(net, ip_vs_ops, ARRAY_SIZE(ip_vs_ops));
 		ipvs->enable = 0;	/* Disable packet reception */
 		smp_wmb();
 		ip_vs_sync_net_cleanup(ipvs);
+	}
 	LeaveFunction(2);
 }
 
@@ -2453,7 +2458,7 @@ static struct pernet_operations ipvs_core_ops = {
 
 static struct pernet_operations ipvs_core_dev_ops = {
 	.init = __ip_vs_dev_init,
-	.exit = __ip_vs_dev_cleanup,
+	.exit_batch = __ip_vs_dev_cleanup_batch,
 };
 
 /*