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 <frugg...@arista.com>
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index f5500f5..e1bb2d8 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -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) {
