[3.8.y.z extended stable] Patch "l2tp: Fix build warning with ipv6 disabled." has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    l2tp: Fix build warning with ipv6 disabled.

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.13.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 81811da0320e829c9c5f3c46f54acac3a1373bbf Mon Sep 17 00:00:00 2001
From: "David S. Miller" <davem at davemloft.net>
Date: Tue, 8 Oct 2013 15:44:26 -0400
Subject: l2tp: Fix build warning with ipv6 disabled.
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

[ Upstream commit 8d8a51e26a6d415e1470759f2cf5f3ee3ee86196 ]

net/l2tp/l2tp_core.c: In function ‘l2tp_verify_udp_checksum’:
net/l2tp/l2tp_core.c:499:22: warning: unused variable ‘tunnel’ [-Wunused-variable]

Create a helper "l2tp_tunnel()" to facilitate this, and as a side
effect get rid of a bunch of unnecessary void pointer casts.

Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 net/l2tp/l2tp_core.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index 8861e9f..02a922c 100644
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -115,6 +115,11 @@ static void l2tp_session_set_header_len(struct l2tp_session *session, int versio
 static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel);
 static void l2tp_tunnel_closeall(struct l2tp_tunnel *tunnel);

+static inline struct l2tp_tunnel *l2tp_tunnel(struct sock *sk)
+{
+	return sk->sk_user_data;
+}
+
 static inline struct l2tp_net *l2tp_pernet(struct net *net)
 {
 	BUG_ON(!net);
@@ -517,7 +522,6 @@ out:
 static inline int l2tp_verify_udp_checksum(struct sock *sk,
 					   struct sk_buff *skb)
 {
-	struct l2tp_tunnel *tunnel = (struct l2tp_tunnel *)sk->sk_user_data;
 	struct udphdr *uh = udp_hdr(skb);
 	u16 ulen = ntohs(uh->len);
 	__wsum psum;
@@ -526,7 +530,7 @@ static inline int l2tp_verify_udp_checksum(struct sock *sk,
 		return 0;

 #if IS_ENABLED(CONFIG_IPV6)
-	if (sk->sk_family == PF_INET6 && !tunnel->v4mapped) {
+	if (sk->sk_family == PF_INET6 && !l2tp_tunnel(sk)->v4mapped) {
 		if (!uh->check) {
 			LIMIT_NETDEBUG(KERN_INFO "L2TP: IPv6: checksum is 0\n");
 			return 1;
@@ -1271,9 +1275,8 @@ EXPORT_SYMBOL_GPL(l2tp_xmit_skb);
  */
 static void l2tp_tunnel_destruct(struct sock *sk)
 {
-	struct l2tp_tunnel *tunnel;
+	struct l2tp_tunnel *tunnel = l2tp_tunnel(sk);

-	tunnel = sk->sk_user_data;
 	if (tunnel == NULL)
 		goto end;

@@ -1596,7 +1599,7 @@ int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32
 	}

 	/* Check if this socket has already been prepped */
-	tunnel = (struct l2tp_tunnel *)sk->sk_user_data;
+	tunnel = l2tp_tunnel(sk);
 	if (tunnel != NULL) {
 		/* This socket has already been prepped */
 		err = -EBUSY;
--
1.8.1.2