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| author | Eric Dumazet <edumazet@google.com> | 2012-12-05 09:18:10 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2012-12-05 16:01:28 -0500 |
| commit | 0e1efe9d5e10921f1e2152b108e013605fca3c9f (patch) | |
| tree | c254570a9058345ea2eb1f319cc5c88cfe8c65ee | |
| parent | cc86802805b5d714a5dc80fe4edecaf1368b09ed (diff) | |
| download | linux-0e1efe9d5e10921f1e2152b108e013605fca3c9f.tar.gz linux-0e1efe9d5e10921f1e2152b108e013605fca3c9f.tar.bz2 linux-0e1efe9d5e10921f1e2152b108e013605fca3c9f.zip | |
ipv6: avoid taking locks at socket dismantle
ipv6_sock_mc_close() is called for ipv6 sockets at close time, and most
of them don't use multicast.
Add a test to avoid contention on a shared spinlock.
Same heuristic applies for ipv6_sock_ac_close(), to avoid contention
on a shared rwlock.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv6/anycast.c | 3 | ||||
| -rw-r--r-- | net/ipv6/mcast.c | 3 |
2 files changed, 6 insertions, 0 deletions
diff --git a/net/ipv6/anycast.c b/net/ipv6/anycast.c index 2f4f584d796d..757a810d8f15 100644 --- a/net/ipv6/anycast.c +++ b/net/ipv6/anycast.c @@ -189,6 +189,9 @@ void ipv6_sock_ac_close(struct sock *sk) struct net *net = sock_net(sk); int prev_index; + if (!np->ipv6_ac_list) + return; + write_lock_bh(&ipv6_sk_ac_lock); pac = np->ipv6_ac_list; np->ipv6_ac_list = NULL; diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c index b19ed51a45bb..28dfa5f3801f 100644 --- a/net/ipv6/mcast.c +++ b/net/ipv6/mcast.c @@ -284,6 +284,9 @@ void ipv6_sock_mc_close(struct sock *sk) struct ipv6_mc_socklist *mc_lst; struct net *net = sock_net(sk); + if (!rcu_access_pointer(np->ipv6_mc_list)) + return; + spin_lock(&ipv6_sk_mc_lock); while ((mc_lst = rcu_dereference_protected(np->ipv6_mc_list, lockdep_is_held(&ipv6_sk_mc_lock))) != NULL) { |