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Date:   Fri, 10 Aug 2018 13:21:57 +0200
From:   Guillaume Nault <g.nault@...halink.fr>
To:     netdev@...r.kernel.org
Cc:     James Chapman <jchapman@...alix.com>
Subject: [PATCH net-next 2/8] l2tp: split l2tp_session_get()

l2tp_session_get() is used for two different purposes. If 'tunnel' is
NULL, the session is searched globally in the supplied network
namespace. Otherwise it is searched exclusively in the tunnel context.

Callers always know the context in which they need to search the
session. But some of them do provide both a namespace and a tunnel,
making the semantic of the call unclear.

This patch defines l2tp_tunnel_get_session() for lookups done in a
tunnel and restricts l2tp_session_get() to namespace searches.

Signed-off-by: Guillaume Nault <g.nault@...halink.fr>
---
 net/l2tp/l2tp_core.c    | 50 ++++++++++++++++++++---------------------
 net/l2tp/l2tp_core.h    |  6 ++---
 net/l2tp/l2tp_ip.c      |  2 +-
 net/l2tp/l2tp_ip6.c     |  2 +-
 net/l2tp/l2tp_netlink.c |  4 ++--
 net/l2tp/l2tp_ppp.c     |  8 +++----
 6 files changed, 36 insertions(+), 36 deletions(-)

diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index ac6a00bcec71..2bd701a58aa6 100644
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -203,44 +203,44 @@ struct l2tp_tunnel *l2tp_tunnel_get_nth(const struct net *net, int nth)
 }
 EXPORT_SYMBOL_GPL(l2tp_tunnel_get_nth);
 
-/* Lookup a session. A new reference is held on the returned session. */
-struct l2tp_session *l2tp_session_get(const struct net *net,
-				      struct l2tp_tunnel *tunnel,
-				      u32 session_id)
+struct l2tp_session *l2tp_tunnel_get_session(struct l2tp_tunnel *tunnel,
+					     u32 session_id)
 {
 	struct hlist_head *session_list;
 	struct l2tp_session *session;
 
-	if (!tunnel) {
-		struct l2tp_net *pn = l2tp_pernet(net);
-
-		session_list = l2tp_session_id_hash_2(pn, session_id);
+	session_list = l2tp_session_id_hash(tunnel, session_id);
 
-		rcu_read_lock_bh();
-		hlist_for_each_entry_rcu(session, session_list, global_hlist) {
-			if (session->session_id == session_id) {
-				l2tp_session_inc_refcount(session);
-				rcu_read_unlock_bh();
+	read_lock_bh(&tunnel->hlist_lock);
+	hlist_for_each_entry(session, session_list, hlist)
+		if (session->session_id == session_id) {
+			l2tp_session_inc_refcount(session);
+			read_unlock_bh(&tunnel->hlist_lock);
 
-				return session;
-			}
+			return session;
 		}
-		rcu_read_unlock_bh();
+	read_unlock_bh(&tunnel->hlist_lock);
 
-		return NULL;
-	}
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(l2tp_tunnel_get_session);
 
-	session_list = l2tp_session_id_hash(tunnel, session_id);
-	read_lock_bh(&tunnel->hlist_lock);
-	hlist_for_each_entry(session, session_list, hlist) {
+struct l2tp_session *l2tp_session_get(const struct net *net, u32 session_id)
+{
+	struct hlist_head *session_list;
+	struct l2tp_session *session;
+
+	session_list = l2tp_session_id_hash_2(l2tp_pernet(net), session_id);
+
+	rcu_read_lock_bh();
+	hlist_for_each_entry_rcu(session, session_list, global_hlist)
 		if (session->session_id == session_id) {
 			l2tp_session_inc_refcount(session);
-			read_unlock_bh(&tunnel->hlist_lock);
+			rcu_read_unlock_bh();
 
 			return session;
 		}
-	}
-	read_unlock_bh(&tunnel->hlist_lock);
+	rcu_read_unlock_bh();
 
 	return NULL;
 }
@@ -872,7 +872,7 @@ static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb)
 	}
 
 	/* Find the session context */
-	session = l2tp_session_get(tunnel->l2tp_net, tunnel, session_id);
+	session = l2tp_tunnel_get_session(tunnel, session_id);
 	if (!session || !session->recv_skb) {
 		if (session)
 			l2tp_session_dec_refcount(session);
diff --git a/net/l2tp/l2tp_core.h b/net/l2tp/l2tp_core.h
index 04a9488c54b4..8480a0af973e 100644
--- a/net/l2tp/l2tp_core.h
+++ b/net/l2tp/l2tp_core.h
@@ -196,12 +196,12 @@ static inline void *l2tp_session_priv(struct l2tp_session *session)
 
 struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id);
 struct l2tp_tunnel *l2tp_tunnel_get_nth(const struct net *net, int nth);
+struct l2tp_session *l2tp_tunnel_get_session(struct l2tp_tunnel *tunnel,
+					     u32 session_id);
 
 void l2tp_tunnel_free(struct l2tp_tunnel *tunnel);
 
-struct l2tp_session *l2tp_session_get(const struct net *net,
-				      struct l2tp_tunnel *tunnel,
-				      u32 session_id);
+struct l2tp_session *l2tp_session_get(const struct net *net, u32 session_id);
 struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth);
 struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net,
 						const char *ifname);
diff --git a/net/l2tp/l2tp_ip.c b/net/l2tp/l2tp_ip.c
index 0bc39cc20a3f..35f6f86d4dcc 100644
--- a/net/l2tp/l2tp_ip.c
+++ b/net/l2tp/l2tp_ip.c
@@ -144,7 +144,7 @@ static int l2tp_ip_recv(struct sk_buff *skb)
 	}
 
 	/* Ok, this is a data packet. Lookup the session. */
-	session = l2tp_session_get(net, NULL, session_id);
+	session = l2tp_session_get(net, session_id);
 	if (!session)
 		goto discard;
 
diff --git a/net/l2tp/l2tp_ip6.c b/net/l2tp/l2tp_ip6.c
index 42f828cf62fb..237f1a4a0b0c 100644
--- a/net/l2tp/l2tp_ip6.c
+++ b/net/l2tp/l2tp_ip6.c
@@ -157,7 +157,7 @@ static int l2tp_ip6_recv(struct sk_buff *skb)
 	}
 
 	/* Ok, this is a data packet. Lookup the session. */
-	session = l2tp_session_get(net, NULL, session_id);
+	session = l2tp_session_get(net, session_id);
 	if (!session)
 		goto discard;
 
diff --git a/net/l2tp/l2tp_netlink.c b/net/l2tp/l2tp_netlink.c
index 357503e5acd5..edbd5d1fbcde 100644
--- a/net/l2tp/l2tp_netlink.c
+++ b/net/l2tp/l2tp_netlink.c
@@ -66,7 +66,7 @@ static struct l2tp_session *l2tp_nl_session_get(struct genl_info *info)
 		session_id = nla_get_u32(info->attrs[L2TP_ATTR_SESSION_ID]);
 		tunnel = l2tp_tunnel_get(net, tunnel_id);
 		if (tunnel) {
-			session = l2tp_session_get(net, tunnel, session_id);
+			session = l2tp_tunnel_get_session(tunnel, session_id);
 			l2tp_tunnel_dec_refcount(tunnel);
 		}
 	}
@@ -627,7 +627,7 @@ static int l2tp_nl_cmd_session_create(struct sk_buff *skb, struct genl_info *inf
 							   &cfg);
 
 	if (ret >= 0) {
-		session = l2tp_session_get(net, tunnel, session_id);
+		session = l2tp_tunnel_get_session(tunnel, session_id);
 		if (session) {
 			ret = l2tp_session_notify(&l2tp_nl_family, info, session,
 						  L2TP_CMD_SESSION_CREATE);
diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
index c33ef9a3f3b5..cd43d02484e4 100644
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -757,7 +757,7 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
 	if (tunnel->peer_tunnel_id == 0)
 		tunnel->peer_tunnel_id = info.peer_tunnel_id;
 
-	session = l2tp_session_get(sock_net(sk), tunnel, info.session_id);
+	session = l2tp_tunnel_get_session(tunnel, info.session_id);
 	if (session) {
 		drop_refcnt = true;
 
@@ -1134,10 +1134,10 @@ static int pppol2tp_tunnel_ioctl(struct l2tp_tunnel *tunnel,
 		}
 		if (stats.session_id != 0) {
 			/* resend to session ioctl handler */
-			struct l2tp_session *session =
-				l2tp_session_get(sock_net(sk), tunnel,
-						 stats.session_id);
+			struct l2tp_session *session;
 
+			session = l2tp_tunnel_get_session(tunnel,
+							  stats.session_id);
 			if (!session) {
 				err = -EBADR;
 				break;
-- 
2.18.0

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