Merge branch 'l2tp-avoid-multiple-assignment-remove-BUG_ON'

Tom Parkin says:

====================
l2tp: avoid multiple assignment, remove BUG_ON

l2tp hasn't been kept up to date with the static analysis checks offered
by checkpatch.pl.

This patchset builds on the series: "l2tp: cleanup checkpatch.pl
warnings" and "l2tp: further checkpatch.pl cleanups" to resolve some of
the remaining checkpatch warnings in l2tp.
====================

Signed-off-by: David S. Miller <[e-mail]>

net/l2tp/l2tp_core.c

···
 		      int length)
 {
 	struct l2tp_tunnel *tunnel = session->tunnel;
+	u32 ns = 0, nr = 0;
 	int offset;
-	u32 ns, nr;
 
 	/* Parse and check optional cookie */
 	if (session->peer_cookie_len > 0) {
···
 	 * the control of the LNS.  If no sequence numbers present but
 	 * we were expecting them, discard frame.
 	 */
-	ns = nr = 0;
 	L2TP_SKB_CB(skb)->has_seq = 0;
 	if (tunnel->version == L2TP_HDR_VER_2) {
 		if (hdrflags & L2TP_HDRFLAG_S) {
···
 
 /* Drop skbs from the session's reorder_q
  */
-static int l2tp_session_queue_purge(struct l2tp_session *session)
+static void l2tp_session_queue_purge(struct l2tp_session *session)
 {
 	struct sk_buff *skb = NULL;
 
-	BUG_ON(!session);
-	BUG_ON(session->magic != L2TP_SESSION_MAGIC);
+	if (WARN_ON(session->magic != L2TP_SESSION_MAGIC))
+		return;
+
 	while ((skb = skb_dequeue(&session->reorder_q))) {
 		atomic_long_inc(&session->stats.rx_errors);
 		kfree_skb(skb);
 	}
-	return 0;
 }
 
 /* Internal UDP receive frame. Do the real work of receiving an L2TP data frame
···
 	}
 
 	/* Point to L2TP header */
-	optr = ptr = skb->data;
+	optr = skb->data;
+	ptr = skb->data;
 
 	/* Get L2TP header flags */
 	hdrflags = ntohs(*(__be16 *)ptr);
···
 	struct hlist_node *walk;
 	struct hlist_node *tmp;
 	struct l2tp_session *session;
-
-	BUG_ON(!tunnel);
 
 	l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: closing all sessions...\n",
 		  tunnel->name);
···
 {
 	struct l2tp_tunnel *tunnel = session->tunnel;
 
-	BUG_ON(refcount_read(&session->ref_count) != 0);
-
 	if (tunnel) {
-		BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
+		if (WARN_ON(tunnel->magic != L2TP_TUNNEL_MAGIC))
+			goto out;
 		l2tp_tunnel_dec_refcount(tunnel);
 	}
 
+out:
 	kfree(session);
 }
 EXPORT_SYMBOL_GPL(l2tp_session_free);

net/l2tp/l2tp_debugfs.c

···
 	if (!pos)
 		goto out;
 
-	BUG_ON(!m->private);
+	if (WARN_ON(!m->private)) {
+		pd = NULL;
+		goto out;
+	}
 	pd = m->private;
 
 	if (!pd->tunnel)

net/l2tp/l2tp_ip.c

···
 		goto discard;
 
 	/* Point to L2TP header */
-	optr = ptr = skb->data;
+	optr = skb->data;
+	ptr = skb->data;
 	session_id = ntohl(*((__be32 *)ptr));
 	ptr += 4;
 
···
 			goto discard_sess;
 
 		/* Point to L2TP header */
-		optr = ptr = skb->data;
+		optr = skb->data;
+		ptr = skb->data;
 		ptr += 4;
 		pr_debug("%s: ip recv\n", tunnel->name);
 		print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);
···
 	    chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST)
 		goto out;
 
-	if (addr->l2tp_addr.s_addr)
-		inet->inet_rcv_saddr = inet->inet_saddr = addr->l2tp_addr.s_addr;
+	if (addr->l2tp_addr.s_addr) {
+		inet->inet_rcv_saddr = addr->l2tp_addr.s_addr;
+		inet->inet_saddr = addr->l2tp_addr.s_addr;
+	}
 	if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST)
 		inet->inet_saddr = 0;  /* Use device */
 

net/l2tp/l2tp_ip6.c

···
 		goto discard;
 
 	/* Point to L2TP header */
-	optr = ptr = skb->data;
+	optr = skb->data;
+	ptr = skb->data;
 	session_id = ntohl(*((__be32 *)ptr));
 	ptr += 4;
 
···
 			goto discard_sess;
 
 		/* Point to L2TP header */
-		optr = ptr = skb->data;
+		optr = skb->data;
+		ptr = skb->data;
 		ptr += 4;
 		pr_debug("%s: ip recv\n", tunnel->name);
 		print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, ptr, length);

net/l2tp/l2tp_ppp.c

···
 		sock_put(sk);
 		goto out;
 	}
-
-	BUG_ON(session->magic != L2TP_SESSION_MAGIC);
+	if (WARN_ON(session->magic != L2TP_SESSION_MAGIC)) {
+		session = NULL;
+		sock_put(sk);
+		goto out;
+	}
 
 out:
 	return session;
···
 
 	if (session) {
 		sk->sk_user_data = NULL;
-		BUG_ON(session->magic != L2TP_SESSION_MAGIC);
+		if (WARN_ON(session->magic != L2TP_SESSION_MAGIC))
+			return;
 		l2tp_session_dec_refcount(session);
 	}
 }
···
 	if (!pos)
 		goto out;
 
-	BUG_ON(!m->private);
+	if (WARN_ON(!m->private)) {
+		pd = NULL;
+		goto out;
+	}
+
 	pd = m->private;
 	net = seq_file_net(m);