Merge branch 'l2tp-remove-unused-code'

Guillaume Nault says:

====================
l2tp: remove unused code

Patch #1 removes the ref/deref mechanism that was originally used to
prevent ppp pseudowires from dropping their sockets. This mechanism
was error prone and isn't used anymore.

Patch #2 removes some module specific refcount debugging.
Patches #3 and #4 take care of some dead code.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

net/l2tp/l2tp_core.c

@@ -100,8 +100,6 @@ struct l2tp_skb_cb {
 
 #define L2TP_SKB_CB(skb)	((struct l2tp_skb_cb *) &skb->cb[sizeof(struct inet_skb_parm)])
 
-static atomic_t l2tp_tunnel_count;
-static atomic_t l2tp_session_count;
 static struct workqueue_struct *l2tp_wq;
 
 /* per-net private data for this module */
@@ -216,12 +214,10 @@ struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id)
 }
 EXPORT_SYMBOL_GPL(l2tp_tunnel_get);
 
-/* Lookup a session. A new reference is held on the returned session.
- * Optionally calls session->ref() too if do_ref is true.
- */
+/* 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, bool do_ref)
+				      u32 session_id)
 {
 	struct hlist_head *session_list;
 	struct l2tp_session *session;
@@ -235,8 +231,6 @@ struct l2tp_session *l2tp_session_get(const struct net *net,
 		hlist_for_each_entry_rcu(session, session_list, global_hlist) {
 			if (session->session_id == session_id) {
 				l2tp_session_inc_refcount(session);
-				if (do_ref && session->ref)
-					session->ref(session);
 				rcu_read_unlock_bh();
 
 				return session;
@@ -252,8 +246,6 @@ struct l2tp_session *l2tp_session_get(const struct net *net,
 	hlist_for_each_entry(session, session_list, hlist) {
 		if (session->session_id == session_id) {
 			l2tp_session_inc_refcount(session);
-			if (do_ref && session->ref)
-				session->ref(session);
 			read_unlock_bh(&tunnel->hlist_lock);
 
 			return session;
@@ -265,8 +257,7 @@ struct l2tp_session *l2tp_session_get(const struct net *net,
 }
 EXPORT_SYMBOL_GPL(l2tp_session_get);
 
-struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth,
-					  bool do_ref)
+struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth)
 {
 	int hash;
 	struct l2tp_session *session;
@@ -277,8 +268,6 @@ struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth,
 		hlist_for_each_entry(session, &tunnel->session_hlist[hash], hlist) {
 			if (++count > nth) {
 				l2tp_session_inc_refcount(session);
-				if (do_ref && session->ref)
-					session->ref(session);
 				read_unlock_bh(&tunnel->hlist_lock);
 				return session;
 			}
@@ -295,8 +284,7 @@ EXPORT_SYMBOL_GPL(l2tp_session_get_nth);
  * This is very inefficient but is only used by management interfaces.
  */
 struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net,
-						const char *ifname,
-						bool do_ref)
+						const char *ifname)
 {
 	struct l2tp_net *pn = l2tp_pernet(net);
 	int hash;
@@ -307,8 +295,6 @@ struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net,
 		hlist_for_each_entry_rcu(session, &pn->l2tp_session_hlist[hash], global_hlist) {
 			if (!strcmp(session->ifname, ifname)) {
 				l2tp_session_inc_refcount(session);
-				if (do_ref && session->ref)
-					session->ref(session);
 				rcu_read_unlock_bh();
 
 				return session;
@@ -371,10 +357,6 @@ int l2tp_session_register(struct l2tp_session *session,
 	hlist_add_head(&session->hlist, head);
 	write_unlock_bh(&tunnel->hlist_lock);
 
-	/* Ignore management session in session count value */
-	if (session->session_id != 0)
-		atomic_inc(&l2tp_session_count);
-
 	return 0;
 
 err_tlock_pnlock:
@@ -489,9 +471,6 @@ static void l2tp_recv_dequeue_skb(struct l2tp_session *session, struct sk_buff *
 		(*session->recv_skb)(session, skb, L2TP_SKB_CB(skb)->length);
 	else
 		kfree_skb(skb);
-
-	if (session->deref)
-		(*session->deref)(session);
 }
 
 /* Dequeue skbs from the session's reorder_q, subject to packet order.
@@ -520,8 +499,6 @@ start:
 			session->reorder_skip = 1;
 			__skb_unlink(skb, &session->reorder_q);
 			kfree_skb(skb);
-			if (session->deref)
-				(*session->deref)(session);
 			continue;
 		}
 
@@ -694,9 +671,6 @@ discard:
  * a data (not control) frame before coming here. Fields up to the
  * session-id have already been parsed and ptr points to the data
  * after the session-id.
- *
- * session->ref() must have been called prior to l2tp_recv_common().
- * session->deref() will be called automatically after skb is processed.
  */
 void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
 		      unsigned char *ptr, unsigned char *optr, u16 hdrflags,
@@ -863,9 +837,6 @@ void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
 discard:
 	atomic_long_inc(&session->stats.rx_errors);
 	kfree_skb(skb);
-
-	if (session->deref)
-		(*session->deref)(session);
 }
 EXPORT_SYMBOL(l2tp_recv_common);
 
@@ -879,8 +850,6 @@ int l2tp_session_queue_purge(struct l2tp_session *session)
 	while ((skb = skb_dequeue(&session->reorder_q))) {
 		atomic_long_inc(&session->stats.rx_errors);
 		kfree_skb(skb);
-		if (session->deref)
-			(*session->deref)(session);
 	}
 	return 0;
 }
@@ -972,13 +941,10 @@ 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, true);
+	session = l2tp_session_get(tunnel->l2tp_net, tunnel, session_id);
 	if (!session || !session->recv_skb) {
-		if (session) {
-			if (session->deref)
-				session->deref(session);
+		if (session)
 			l2tp_session_dec_refcount(session);
-		}
 
 		/* Not found? Pass to userspace to deal with */
 		l2tp_info(tunnel, L2TP_MSG_DATA,
@@ -1279,7 +1245,6 @@ static void l2tp_tunnel_destruct(struct sock *sk)
 	spin_lock_bh(&pn->l2tp_tunnel_list_lock);
 	list_del_rcu(&tunnel->list);
 	spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
-	atomic_dec(&l2tp_tunnel_count);
 
 	l2tp_tunnel_closeall(tunnel);
 
@@ -1322,9 +1287,6 @@ again:
 			if (test_and_set_bit(0, &session->dead))
 				goto again;
 
-			if (session->ref != NULL)
-				(*session->ref)(session);
-
 			write_unlock_bh(&tunnel->hlist_lock);
 
 			__l2tp_session_unhash(session);
@@ -1333,9 +1295,6 @@ again:
 			if (session->session_close != NULL)
 				(*session->session_close)(session);
 
-			if (session->deref != NULL)
-				(*session->deref)(session);
-
 			l2tp_session_dec_refcount(session);
 
 			write_lock_bh(&tunnel->hlist_lock);
@@ -1666,7 +1625,6 @@ int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32
 
 	/* Add tunnel to our list */
 	INIT_LIST_HEAD(&tunnel->list);
-	atomic_inc(&l2tp_tunnel_count);
 
 	/* Bump the reference count. The tunnel context is deleted
 	 * only when this drops to zero. Must be done before list insertion
@@ -1712,8 +1670,6 @@ void l2tp_session_free(struct l2tp_session *session)
 
 	if (tunnel) {
 		BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
-		if (session->session_id != 0)
-			atomic_dec(&l2tp_session_count);
 		sock_put(tunnel->sock);
 		session->tunnel = NULL;
 		l2tp_tunnel_dec_refcount(tunnel);
@@ -1759,15 +1715,13 @@ int l2tp_session_delete(struct l2tp_session *session)
 	if (test_and_set_bit(0, &session->dead))
 		return 0;
 
-	if (session->ref)
-		(*session->ref)(session);
 	__l2tp_session_unhash(session);
 	l2tp_session_queue_purge(session);
 	if (session->session_close != NULL)
 		(*session->session_close)(session);
-	if (session->deref)
-		(*session->deref)(session);
+
 	l2tp_session_dec_refcount(session);
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(l2tp_session_delete);

net/l2tp/l2tp_core.h

@@ -129,8 +129,6 @@ struct l2tp_session {
 	int (*build_header)(struct l2tp_session *session, void *buf);
 	void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len);
 	void (*session_close)(struct l2tp_session *session);
-	void (*ref)(struct l2tp_session *session);
-	void (*deref)(struct l2tp_session *session);
 #if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
 	void (*show)(struct seq_file *m, void *priv);
 #endif
@@ -245,12 +243,10 @@ struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id);
 
 struct l2tp_session *l2tp_session_get(const struct net *net,
 				      struct l2tp_tunnel *tunnel,
-				      u32 session_id, bool do_ref);
-struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth,
-					  bool do_ref);
+				      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,
-						bool do_ref);
+						const char *ifname);
 struct l2tp_tunnel *l2tp_tunnel_find(const struct net *net, u32 tunnel_id);
 struct l2tp_tunnel *l2tp_tunnel_find_nth(const struct net *net, int nth);
 
@@ -298,37 +294,17 @@ static inline void l2tp_tunnel_dec_refcount(struct l2tp_tunnel *tunnel)
 /* Session reference counts. Incremented when code obtains a reference
  * to a session.
  */
-static inline void l2tp_session_inc_refcount_1(struct l2tp_session *session)
+static inline void l2tp_session_inc_refcount(struct l2tp_session *session)
 {
 	refcount_inc(&session->ref_count);
 }
 
-static inline void l2tp_session_dec_refcount_1(struct l2tp_session *session)
+static inline void l2tp_session_dec_refcount(struct l2tp_session *session)
 {
 	if (refcount_dec_and_test(&session->ref_count))
 		l2tp_session_free(session);
 }
 
-#ifdef L2TP_REFCNT_DEBUG
-#define l2tp_session_inc_refcount(_s)					\
-do {									\
-	pr_debug("l2tp_session_inc_refcount: %s:%d %s: cnt=%d\n",	\
-		 __func__, __LINE__, (_s)->name,			\
-		 refcount_read(&_s->ref_count));			\
-	l2tp_session_inc_refcount_1(_s);				\
-} while (0)
-#define l2tp_session_dec_refcount(_s)					\
-do {									\
-	pr_debug("l2tp_session_dec_refcount: %s:%d %s: cnt=%d\n",	\
-		 __func__, __LINE__, (_s)->name,			\
-		 refcount_read(&_s->ref_count));			\
-	l2tp_session_dec_refcount_1(_s);				\
-} while (0)
-#else
-#define l2tp_session_inc_refcount(s) l2tp_session_inc_refcount_1(s)
-#define l2tp_session_dec_refcount(s) l2tp_session_dec_refcount_1(s)
-#endif
-
 #define l2tp_printk(ptr, type, func, fmt, ...)				\
 do {									\
 	if (((ptr)->debug) & (type))					\

net/l2tp/l2tp_debugfs.c

@@ -53,7 +53,7 @@ static void l2tp_dfs_next_tunnel(struct l2tp_dfs_seq_data *pd)
 
 static void l2tp_dfs_next_session(struct l2tp_dfs_seq_data *pd)
 {
-	pd->session = l2tp_session_get_nth(pd->tunnel, pd->session_idx, true);
+	pd->session = l2tp_session_get_nth(pd->tunnel, pd->session_idx);
 	pd->session_idx++;
 
 	if (pd->session == NULL) {
@@ -241,8 +241,6 @@ static int l2tp_dfs_seq_show(struct seq_file *m, void *v)
 		l2tp_dfs_seq_tunnel_show(m, pd->tunnel);
 	} else {
 		l2tp_dfs_seq_session_show(m, pd->session);
-		if (pd->session->deref)
-			pd->session->deref(pd->session);
 		l2tp_session_dec_refcount(pd->session);
 	}
 

net/l2tp/l2tp_eth.c

@@ -41,7 +41,6 @@
 
 /* via netdev_priv() */
 struct l2tp_eth {
-	struct net_device	*dev;
 	struct sock		*tunnel_sock;
 	struct l2tp_session	*session;
 	atomic_long_t		tx_bytes;
@@ -60,9 +59,6 @@ struct l2tp_eth_sess {
 
 static int l2tp_eth_dev_init(struct net_device *dev)
 {
-	struct l2tp_eth *priv = netdev_priv(dev);
-
-	priv->dev = dev;
 	eth_hw_addr_random(dev);
 	eth_broadcast_addr(dev->broadcast);
 	netdev_lockdep_set_classes(dev);
@@ -315,7 +311,6 @@ static int l2tp_eth_create(struct net *net, struct l2tp_tunnel *tunnel,
 	l2tp_eth_adjust_mtu(tunnel, session, dev);
 
 	priv = netdev_priv(dev);
-	priv->dev = dev;
 	priv->session = session;
 
 	priv->tunnel_sock = tunnel->sock;

net/l2tp/l2tp_ip.c

@@ -143,7 +143,7 @@ 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, true);
+	session = l2tp_session_get(net, NULL, session_id);
 	if (!session)
 		goto discard;
 
@@ -205,8 +205,6 @@ pass_up:
 	return sk_receive_skb(sk, skb, 1);
 
 discard_sess:
-	if (session->deref)
-		session->deref(session);
 	l2tp_session_dec_refcount(session);
 	goto discard;
 

net/l2tp/l2tp_ip6.c

@@ -156,7 +156,7 @@ 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, true);
+	session = l2tp_session_get(net, NULL, session_id);
 	if (!session)
 		goto discard;
 
@@ -219,8 +219,6 @@ pass_up:
 	return sk_receive_skb(sk, skb, 1);
 
 discard_sess:
-	if (session->deref)
-		session->deref(session);
 	l2tp_session_dec_refcount(session);
 	goto discard;
 

net/l2tp/l2tp_netlink.c

@@ -48,8 +48,7 @@ static int l2tp_nl_session_send(struct sk_buff *skb, u32 portid, u32 seq,
 /* Accessed under genl lock */
 static const struct l2tp_nl_cmd_ops *l2tp_nl_cmd_ops[__L2TP_PWTYPE_MAX];
 
-static struct l2tp_session *l2tp_nl_session_get(struct genl_info *info,
-						bool do_ref)
+static struct l2tp_session *l2tp_nl_session_get(struct genl_info *info)
 {
 	u32 tunnel_id;
 	u32 session_id;
@@ -60,15 +59,14 @@ static struct l2tp_session *l2tp_nl_session_get(struct genl_info *info,
 
 	if (info->attrs[L2TP_ATTR_IFNAME]) {
 		ifname = nla_data(info->attrs[L2TP_ATTR_IFNAME]);
-		session = l2tp_session_get_by_ifname(net, ifname, do_ref);
+		session = l2tp_session_get_by_ifname(net, ifname);
 	} else if ((info->attrs[L2TP_ATTR_SESSION_ID]) &&
 		   (info->attrs[L2TP_ATTR_CONN_ID])) {
 		tunnel_id = nla_get_u32(info->attrs[L2TP_ATTR_CONN_ID]);
 		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,
-						   do_ref);
+			session = l2tp_session_get(net, tunnel, session_id);
 			l2tp_tunnel_dec_refcount(tunnel);
 		}
 	}
@@ -649,7 +647,7 @@ 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, false);
+		session = l2tp_session_get(net, tunnel, session_id);
 		if (session) {
 			ret = l2tp_session_notify(&l2tp_nl_family, info, session,
 						  L2TP_CMD_SESSION_CREATE);
@@ -669,7 +667,7 @@ static int l2tp_nl_cmd_session_delete(struct sk_buff *skb, struct genl_info *inf
 	struct l2tp_session *session;
 	u16 pw_type;
 
-	session = l2tp_nl_session_get(info, true);
+	session = l2tp_nl_session_get(info);
 	if (session == NULL) {
 		ret = -ENODEV;
 		goto out;
@@ -683,8 +681,6 @@ static int l2tp_nl_cmd_session_delete(struct sk_buff *skb, struct genl_info *inf
 		if (l2tp_nl_cmd_ops[pw_type] && l2tp_nl_cmd_ops[pw_type]->session_delete)
 			ret = (*l2tp_nl_cmd_ops[pw_type]->session_delete)(session);
 
-	if (session->deref)
-		session->deref(session);
 	l2tp_session_dec_refcount(session);
 
 out:
@@ -696,7 +692,7 @@ static int l2tp_nl_cmd_session_modify(struct sk_buff *skb, struct genl_info *inf
 	int ret = 0;
 	struct l2tp_session *session;
 
-	session = l2tp_nl_session_get(info, false);
+	session = l2tp_nl_session_get(info);
 	if (session == NULL) {
 		ret = -ENODEV;
 		goto out;
@@ -828,7 +824,7 @@ static int l2tp_nl_cmd_session_get(struct sk_buff *skb, struct genl_info *info)
 	struct sk_buff *msg;
 	int ret;
 
-	session = l2tp_nl_session_get(info, false);
+	session = l2tp_nl_session_get(info);
 	if (session == NULL) {
 		ret = -ENODEV;
 		goto err;
@@ -874,7 +870,7 @@ static int l2tp_nl_cmd_session_dump(struct sk_buff *skb, struct netlink_callback
 				goto out;
 		}
 
-		session = l2tp_session_get_nth(tunnel, si, false);
+		session = l2tp_session_get_nth(tunnel, si);
 		if (session == NULL) {
 			ti++;
 			tunnel = NULL;

net/l2tp/l2tp_ppp.c

@@ -742,7 +742,7 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
 	if (tunnel->peer_tunnel_id == 0)
 		tunnel->peer_tunnel_id = peer_tunnel_id;
 
-	session = l2tp_session_get(sock_net(sk), tunnel, session_id, false);
+	session = l2tp_session_get(sock_net(sk), tunnel, session_id);
 	if (session) {
 		drop_refcnt = true;
 		ps = l2tp_session_priv(session);
@@ -1193,13 +1193,11 @@ static int pppol2tp_tunnel_ioctl(struct l2tp_tunnel *tunnel,
 			/* resend to session ioctl handler */
 			struct l2tp_session *session =
 				l2tp_session_get(sock_net(sk), tunnel,
-						 stats.session_id, true);
+						 stats.session_id);
 
 			if (session) {
 				err = pppol2tp_session_ioctl(session, cmd,
 							     arg);
-				if (session->deref)
-					session->deref(session);
 				l2tp_session_dec_refcount(session);
 			} else {
 				err = -EBADR;
@@ -1615,7 +1613,7 @@ static void pppol2tp_next_tunnel(struct net *net, struct pppol2tp_seq_data *pd)
 
 static void pppol2tp_next_session(struct net *net, struct pppol2tp_seq_data *pd)
 {
-	pd->session = l2tp_session_get_nth(pd->tunnel, pd->session_idx, true);
+	pd->session = l2tp_session_get_nth(pd->tunnel, pd->session_idx);
 	pd->session_idx++;
 
 	if (pd->session == NULL) {
@@ -1758,8 +1756,6 @@ static int pppol2tp_seq_show(struct seq_file *m, void *v)
 		pppol2tp_seq_tunnel_show(m, pd->tunnel);
 	} else {
 		pppol2tp_seq_session_show(m, pd->session);
-		if (pd->session->deref)
-			pd->session->deref(pd->session);
 		l2tp_session_dec_refcount(pd->session);
 	}