ipv6: switch inet6_dump_ifinfo() to RCU protection

No longer hold RTNL while calling inet6_dump_ifinfo()
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Donald Hunter <donald.hunter@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/addrconf.c

@@ -7462,7 +7462,7 @@ int __init addrconf_init(void)
 	rtnl_af_register(&inet6_ops);
 
 	err = rtnl_register_module(THIS_MODULE, PF_INET6, RTM_GETLINK,
-				   NULL, inet6_dump_ifinfo, 0);
+				   NULL, inet6_dump_ifinfo, RTNL_FLAG_DUMP_UNLOCKED);
 	if (err < 0)
 		goto errout;