l2tp: remove useless duplicate session detection in l2tp_netlink

commit af87ae465abdc070de0dc35d6c6a9e7a8cd82987 upstream.

There's no point in checking for duplicate sessions at the beginning of
l2tp_nl_cmd_session_create(); the ->session_create() callbacks already
return -EEXIST when the session already exists.

Furthermore, even if l2tp_session_find() returns NULL, a new session
might be created right after the test. So relying on ->session_create()
to avoid duplicate session is the only sane behaviour.

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.2: also delete the now-unused local variable]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/net/l2tp/l2tp_netlink.c b/net/l2tp/l2tp_netlink.c
index 061e767..bb34f63 100644 (file)
--- a/net/l2tp/l2tp_netlink.c
+++ b/net/l2tp/l2tp_netlink.c
@@ -361,7 +361,6 @@ static int l2tp_nl_cmd_session_create(struct sk_buff *skb, struct genl_info *inf
        u32 peer_session_id;
        int ret = 0;
        struct l2tp_tunnel *tunnel;
-       struct l2tp_session *session;
        struct l2tp_session_cfg cfg = { 0, };
        struct net *net = genl_info_net(info);
 
@@ -381,11 +380,6 @@ static int l2tp_nl_cmd_session_create(struct sk_buff *skb, struct genl_info *inf
                goto out;
        }
        session_id = nla_get_u32(info->attrs[L2TP_ATTR_SESSION_ID]);
-       session = l2tp_session_find(net, tunnel, session_id);
-       if (session) {
-               ret = -EEXIST;
-               goto out;
-       }
 
        if (!info->attrs[L2TP_ATTR_PEER_SESSION_ID]) {
                ret = -EINVAL;