ipv6: try not to take rtnl_lock in ip6mr_sk_done

Avoid traversing the list of mr6_tables (which requires the
rtnl_lock) in ip6mr_sk_done(), when we know in advance that
a match will not be found.
This can happen when rawv6_close()/ip6mr_sk_done() is invoked
on non-mroute6 sockets.
This patch helps reduce rtnl_lock contention when destroying
a large number of net namespaces, each having a non-mroute6
raw socket.

v2: same patch, only fixed subject line and expanded comment.

Signed-off-by: Francesco Ruggeri <fruggeri@arista.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Francesco Ruggeri 2017-11-08 11:23:46 -08:00 committed by David S. Miller
parent 07842561a8
commit 338d182fa5

View file

@ -1617,6 +1617,10 @@ int ip6mr_sk_done(struct sock *sk)
struct net *net = sock_net(sk);
struct mr6_table *mrt;
if (sk->sk_type != SOCK_RAW ||
inet_sk(sk)->inet_num != IPPROTO_ICMPV6)
return err;
rtnl_lock();
ip6mr_for_each_table(mrt, net) {
if (sk == mrt->mroute6_sk) {