net: Convert broute_net_ops, frame_filter_net_ops and frame_nat_net_ops

These pernet_operations use ebt_register_table() and
ebt_unregister_table() to act on the tables, which
are used as argument in ebt_do_table(), called from
ebtables hooks.

Since there are no net-related bridge packets in-flight,
when the init and exit methods are called, these
pernet_operations are safe to be executed in parallel
with any other.

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/bridge/netfilter/ebtable_broute.c

@@ -77,6 +77,7 @@ static void __net_exit broute_net_exit(struct net *net)
 static struct pernet_operations broute_net_ops = {
 	.init = broute_net_init,
 	.exit = broute_net_exit,
+	.async = true,
 };
 
 static int __init ebtable_broute_init(void)

net/bridge/netfilter/ebtable_filter.c

@@ -105,6 +105,7 @@ static void __net_exit frame_filter_net_exit(struct net *net)
 static struct pernet_operations frame_filter_net_ops = {
 	.init = frame_filter_net_init,
 	.exit = frame_filter_net_exit,
+	.async = true,
 };
 
 static int __init ebtable_filter_init(void)

net/bridge/netfilter/ebtable_nat.c

@@ -105,6 +105,7 @@ static void __net_exit frame_nat_net_exit(struct net *net)
 static struct pernet_operations frame_nat_net_ops = {
 	.init = frame_nat_net_init,
 	.exit = frame_nat_net_exit,
+	.async = true,
 };
 
 static int __init ebtable_nat_init(void)