netlink: update listeners directly when removing socket

The code is now confusing to read - first in one function down
(netlink_remove) any group subscriptions are implicitly removed
by calling __sk_del_bind_node(), but the subscriber database is
only updated far later by calling netlink_update_listeners().

Move the latter call to just after removal from the list so it
is easier to follow the code.

This also enables moving the locking inside the kernel-socket
conditional, which improves the normal socket destruction path.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index b4cf8ee..6a9fb7c 100644 (file)
--- 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;
@@ -1241,10 +1243,8 @@ 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();
 
        kfree(nlk->groups);
        nlk->groups = NULL;