netlink: Lockless lookup with RCU grace period in socket release

Defers the release of the socket reference using call_rcu() to
allow using an RCU read-side protected call to rhashtable_lookup()

This restores behaviour and performance gains as previously
introduced by e341694 ("netlink: Convert netlink_lookup() to use
RCU protected hash table") without the side effect of severely
delayed socket destruction.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 0 deletions

diff --git a/net/netlink/af_netlink.h b/net/netlink/af_netlink.h
index f123a88496f8..fd96fa76202a 100644
--- a/net/netlink/af_netlink.h
+++ b/net/netlink/af_netlink.h
@@ -50,6 +50,7 @@ struct netlink_sock {
 #endif /* CONFIG_NETLINK_MMAP */
 
         struct rhash_head       node;
+        struct rcu_head         rcu;
 };
 
 static inline struct netlink_sock *nlk_sk(struct sock *sk)