Merge branch 'netlink_multicast'

Johannes Berg says:

====================
netlink/genetlink cleanups & multicast improvements

I'm looking at using the multicast group functionality in a way that would
benefit from knowing when there are subscribers to avoid collecting the
required data when there aren't any. During this I noticed that the unbind
for multicast groups doesn't actually work - it's never called when sockets
are closed. Luckily, nobody actually uses the functionality.

While looking at the code trying to find why it's not called and where the
multicast listeners are actually removed, I found the potential cleanup in
patch 3. Patch 2 also has a cleanup for a generic netlink API in this area.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 16 insertions, 9 deletions

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 074cf3e91c6f..f29b63fad932 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1091,8 +1091,10 @@ static void netlink_remove(struct sock *sk)
 	mutex_unlock(&nl_sk_hash_lock);
 
 	netlink_table_grab();
-	if (nlk_sk(sk)->subscriptions)
+	if (nlk_sk(sk)->subscriptions) {
 		__sk_del_bind_node(sk);
+		netlink_update_listeners(sk);
+	}
 	netlink_table_ungrab();
 }
 
@@ -1226,8 +1228,8 @@ static int netlink_release(struct socket *sock)
 
 	module_put(nlk->module);
 
-	netlink_table_grab();
 	if (netlink_is_kernel(sk)) {
+		netlink_table_grab();
 		BUG_ON(nl_table[sk->sk_protocol].registered == 0);
 		if (--nl_table[sk->sk_protocol].registered == 0) {
 			struct listeners *old;
@@ -1241,11 +1243,16 @@ static int netlink_release(struct socket *sock)
 			nl_table[sk->sk_protocol].flags = 0;
 			nl_table[sk->sk_protocol].registered = 0;
 		}
-	} else if (nlk->subscriptions) {
-		netlink_update_listeners(sk);
+		netlink_table_ungrab();
 	}
-	netlink_table_ungrab();
 
+	if (nlk->netlink_unbind) {
+		int i;
+
+		for (i = 0; i < nlk->ngroups; i++)
+			if (test_bit(i, nlk->groups))
+				nlk->netlink_unbind(i + 1);
+	}
 	kfree(nlk->groups);
 	nlk->groups = NULL;
 
@@ -1410,8 +1417,8 @@ static int netlink_realloc_groups(struct sock *sk)
 	return err;
 }
 
-static void netlink_unbind(int group, long unsigned int groups,
-			   struct netlink_sock *nlk)
+static void netlink_undo_bind(int group, long unsigned int groups,
+			      struct netlink_sock *nlk)
 {
 	int undo;
 
@@ -1461,7 +1468,7 @@ static int netlink_bind(struct socket *sock, struct sockaddr *addr,
 			err = nlk->netlink_bind(group);
 			if (!err)
 				continue;
-			netlink_unbind(group, groups, nlk);
+			netlink_undo_bind(group, groups, nlk);
 			return err;
 		}
 	}
@@ -1471,7 +1478,7 @@ static int netlink_bind(struct socket *sock, struct sockaddr *addr,
 			netlink_insert(sk, net, nladdr->nl_pid) :
 			netlink_autobind(sock);
 		if (err) {
-			netlink_unbind(nlk->ngroups, groups, nlk);
+			netlink_undo_bind(nlk->ngroups, groups, nlk);
 			return err;
 		}
 	}