[PATCH net-next 0/2] l2tp: drop l2tp_session_find()

[PATCH net-next 0/2] l2tp: drop l2tp_session_find()

[Guillaume Nault]

l2tp_netlink is the last user of l2tp_session_find(), but that call is
useless. Let's remove it and drop l2tp_session_find() definitely.

Guillaume Nault (2):
  l2tp: remove useless duplicate session detection in l2tp_netlink
  l2tp: remove l2tp_session_find()

 net/l2tp/l2tp_core.c    | 51 +------------------------------------------------
 net/l2tp/l2tp_core.h    |  3 ---
 net/l2tp/l2tp_netlink.c |  5 -----
 3 files changed, 1 insertion(+), 58 deletions(-)

-- 
2.11.0

[PATCH net-next 1/2] l2tp: remove useless duplicate session detection in l2tp_netlink

[Guillaume Nault]

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>
---
 net/l2tp/l2tp_netlink.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/net/l2tp/l2tp_netlink.c b/net/l2tp/l2tp_netlink.c
index 7e3e669baac4..12cfcd0ca807 100644
--- a/net/l2tp/l2tp_netlink.c
+++ b/net/l2tp/l2tp_netlink.c
@@ -521,11 +521,6 @@ 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;
-- 
2.11.0

[PATCH net-next 2/2] l2tp: remove l2tp_session_find()

[Guillaume Nault]

This function isn't used anymore.

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
---
 net/l2tp/l2tp_core.c | 51 +--------------------------------------------------
 net/l2tp/l2tp_core.h |  3 ---
 2 files changed, 1 insertion(+), 53 deletions(-)

diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index e37d9554da7b..154974be1eed 100644
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -217,27 +217,6 @@ static void l2tp_tunnel_sock_put(struct sock *sk)
 	sock_put(sk);
 }
 
-/* Lookup a session by id in the global session list
- */
-static struct l2tp_session *l2tp_session_find_2(struct net *net, u32 session_id)
-{
-	struct l2tp_net *pn = l2tp_pernet(net);
-	struct hlist_head *session_list =
-		l2tp_session_id_hash_2(pn, session_id);
-	struct l2tp_session *session;
-
-	rcu_read_lock_bh();
-	hlist_for_each_entry_rcu(session, session_list, global_hlist) {
-		if (session->session_id == session_id) {
-			rcu_read_unlock_bh();
-			return session;
-		}
-	}
-	rcu_read_unlock_bh();
-
-	return NULL;
-}
-
 /* Session hash list.
  * The session_id SHOULD be random according to RFC2661, but several
  * L2TP implementations (Cisco and Microsoft) use incrementing
@@ -250,35 +229,7 @@ l2tp_session_id_hash(struct l2tp_tunnel *tunnel, u32 session_id)
 	return &tunnel->session_hlist[hash_32(session_id, L2TP_HASH_BITS)];
 }
 
-/* Lookup a session by id
- */
-struct l2tp_session *l2tp_session_find(struct net *net, struct l2tp_tunnel *tunnel, u32 session_id)
-{
-	struct hlist_head *session_list;
-	struct l2tp_session *session;
-
-	/* In L2TPv3, session_ids are unique over all tunnels and we
-	 * sometimes need to look them up before we know the
-	 * tunnel.
-	 */
-	if (tunnel == NULL)
-		return l2tp_session_find_2(net, session_id);
-
-	session_list = l2tp_session_id_hash(tunnel, session_id);
-	read_lock_bh(&tunnel->hlist_lock);
-	hlist_for_each_entry(session, session_list, hlist) {
-		if (session->session_id == session_id) {
-			read_unlock_bh(&tunnel->hlist_lock);
-			return session;
-		}
-	}
-	read_unlock_bh(&tunnel->hlist_lock);
-
-	return NULL;
-}
-EXPORT_SYMBOL_GPL(l2tp_session_find);
-
-/* Like l2tp_session_find() but takes a reference on the returned session.
+/* Lookup a session. A new reference is held on the returned session.
  * Optionally calls session->ref() too if do_ref is true.
  */
 struct l2tp_session *l2tp_session_get(struct net *net,
diff --git a/net/l2tp/l2tp_core.h b/net/l2tp/l2tp_core.h
index 8ce7818c7a9d..a3248e18badb 100644
--- a/net/l2tp/l2tp_core.h
+++ b/net/l2tp/l2tp_core.h
@@ -233,9 +233,6 @@ static inline struct l2tp_tunnel *l2tp_sock_to_tunnel(struct sock *sk)
 struct l2tp_session *l2tp_session_get(struct net *net,
 				      struct l2tp_tunnel *tunnel,
 				      u32 session_id, bool do_ref);
-struct l2tp_session *l2tp_session_find(struct net *net,
-				       struct l2tp_tunnel *tunnel,
-				       u32 session_id);
 struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth,
 					  bool do_ref);
 struct l2tp_session *l2tp_session_get_by_ifname(struct net *net, char *ifname,
-- 
2.11.0

Re: [PATCH net-next 0/2] l2tp: drop l2tp_session_find()

[David Miller]

From: Guillaume Nault <g.nault@alphalink.fr>
Date: Tue, 11 Apr 2017 13:12:03 +0200

> l2tp_netlink is the last user of l2tp_session_find(), but that call is
> useless. Let's remove it and drop l2tp_session_find() definitely.

Series applied, thank you.