Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next

Pull networking updates from David Miller:
 "Highlights:

   1) Maintain the TCP retransmit queue using an rbtree, with 1GB
      windows at 100Gb this really has become necessary. From Eric
      Dumazet.

   2) Multi-program support for cgroup+bpf, from Alexei Starovoitov.

   3) Perform broadcast flooding in hardware in mv88e6xxx, from Andrew
      Lunn.

   4) Add meter action support to openvswitch, from Andy Zhou.

   5) Add a data meta pointer for BPF accessible packets, from Daniel
      Borkmann.

   6) Namespace-ify almost all TCP sysctl knobs, from Eric Dumazet.

   7) Turn on Broadcom Tags in b53 driver, from Florian Fainelli.

   8) More work to move the RTNL mutex down, from Florian Westphal.

   9) Add 'bpftool' utility, to help with bpf program introspection.
      From Jakub Kicinski.

  10) Add new 'cpumap' type for XDP_REDIRECT action, from Jesper
      Dangaard Brouer.

  11) Support 'blocks' of transformations in the packet scheduler which
      can span multiple network devices, from Jiri Pirko.

  12) TC flower offload support in cxgb4, from Kumar Sanghvi.

  13) Priority based stream scheduler for SCTP, from Marcelo Ricardo
      Leitner.

  14) Thunderbolt networking driver, from Amir Levy and Mika Westerberg.

  15) Add RED qdisc offloadability, and use it in mlxsw driver. From
      Nogah Frankel.

  16) eBPF based device controller for cgroup v2, from Roman Gushchin.

  17) Add some fundamental tracepoints for TCP, from Song Liu.

  18) Remove garbage collection from ipv6 route layer, this is a
      significant accomplishment. From Wei Wang.

  19) Add multicast route offload support to mlxsw, from Yotam Gigi"

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (2177 commits)
  tcp: highest_sack fix
  geneve: fix fill_info when link down
  bpf: fix lockdep splat
  net: cdc_ncm: GetNtbFormat endian fix
  openvswitch: meter: fix NULL pointer dereference in ovs_meter_cmd_reply_start
  netem: remove unnecessary 64 bit modulus
  netem: use 64 bit divide by rate
  tcp: Namespace-ify sysctl_tcp_default_congestion_control
  net: Protect iterations over net::fib_notifier_ops in fib_seq_sum()
  ipv6: set all.accept_dad to 0 by default
  uapi: fix linux/tls.h userspace compilation error
  usbnet: ipheth: prevent TX queue timeouts when device not ready
  vhost_net: conditionally enable tx polling
  uapi: fix linux/rxrpc.h userspace compilation errors
  net: stmmac: fix LPI transitioning for dwmac4
  atm: horizon: Fix irq release error
  net-sysfs: trigger netlink notification on ifalias change via sysfs
  openvswitch: Using kfree_rcu() to simplify the code
  openvswitch: Make local function ovs_nsh_key_attr_size() static
  openvswitch: Fix return value check in ovs_meter_cmd_features()
  ...

1 files changed, 165 insertions, 155 deletions

diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
index 0c2738349442..b412fc3351dc 100644
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -122,10 +122,11 @@
 struct pppol2tp_session {
 	int			owner;		/* pid that opened the socket */
 
-	struct sock		*sock;		/* Pointer to the session
+	struct mutex		sk_lock;	/* Protects .sk */
+	struct sock __rcu	*sk;		/* Pointer to the session
 						 * PPPoX socket */
-	struct sock		*tunnel_sock;	/* Pointer to the tunnel UDP
-						 * socket */
+	struct sock		*__sk;		/* Copy of .sk, for cleanup */
+	struct rcu_head		rcu;		/* For asynchronous release */
 	int			flags;		/* accessed by PPPIOCGFLAGS.
 						 * Unused. */
 };
@@ -138,6 +139,24 @@ static const struct ppp_channel_ops pppol2tp_chan_ops = {
 
 static const struct proto_ops pppol2tp_ops;
 
+/* Retrieves the pppol2tp socket associated to a session.
+ * A reference is held on the returned socket, so this function must be paired
+ * with sock_put().
+ */
+static struct sock *pppol2tp_session_get_sock(struct l2tp_session *session)
+{
+	struct pppol2tp_session *ps = l2tp_session_priv(session);
+	struct sock *sk;
+
+	rcu_read_lock();
+	sk = rcu_dereference(ps->sk);
+	if (sk)
+		sock_hold(sk);
+	rcu_read_unlock();
+
+	return sk;
+}
+
 /* Helpers to obtain tunnel/session contexts from sockets.
  */
 static inline struct l2tp_session *pppol2tp_sock_to_session(struct sock *sk)
@@ -224,7 +243,8 @@ static void pppol2tp_recv(struct l2tp_session *session, struct sk_buff *skb, int
 	/* If the socket is bound, send it in to PPP's input queue. Otherwise
 	 * queue it on the session socket.
 	 */
-	sk = ps->sock;
+	rcu_read_lock();
+	sk = rcu_dereference(ps->sk);
 	if (sk == NULL)
 		goto no_sock;
 
@@ -247,30 +267,16 @@ static void pppol2tp_recv(struct l2tp_session *session, struct sk_buff *skb, int
 			kfree_skb(skb);
 		}
 	}
+	rcu_read_unlock();
 
 	return;
 
 no_sock:
+	rcu_read_unlock();
 	l2tp_info(session, L2TP_MSG_DATA, "%s: no socket\n", session->name);
 	kfree_skb(skb);
 }
 
-static void pppol2tp_session_sock_hold(struct l2tp_session *session)
-{
-	struct pppol2tp_session *ps = l2tp_session_priv(session);
-
-	if (ps->sock)
-		sock_hold(ps->sock);
-}
-
-static void pppol2tp_session_sock_put(struct l2tp_session *session)
-{
-	struct pppol2tp_session *ps = l2tp_session_priv(session);
-
-	if (ps->sock)
-		sock_put(ps->sock);
-}
-
 /************************************************************************
  * Transmit handling
  ***********************************************************************/
@@ -287,7 +293,6 @@ static int pppol2tp_sendmsg(struct socket *sock, struct msghdr *m,
 	int error;
 	struct l2tp_session *session;
 	struct l2tp_tunnel *tunnel;
-	struct pppol2tp_session *ps;
 	int uhlen;
 
 	error = -ENOTCONN;
@@ -300,10 +305,7 @@ static int pppol2tp_sendmsg(struct socket *sock, struct msghdr *m,
 	if (session == NULL)
 		goto error;
 
-	ps = l2tp_session_priv(session);
-	tunnel = l2tp_sock_to_tunnel(ps->tunnel_sock);
-	if (tunnel == NULL)
-		goto error_put_sess;
+	tunnel = session->tunnel;
 
 	uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
 
@@ -314,7 +316,7 @@ static int pppol2tp_sendmsg(struct socket *sock, struct msghdr *m,
 			   2 + total_len, /* 2 bytes for PPP_ALLSTATIONS & PPP_UI */
 			   0, GFP_KERNEL);
 	if (!skb)
-		goto error_put_sess_tun;
+		goto error_put_sess;
 
 	/* Reserve space for headers. */
 	skb_reserve(skb, NET_SKB_PAD);
@@ -332,20 +334,17 @@ static int pppol2tp_sendmsg(struct socket *sock, struct msghdr *m,
 	error = memcpy_from_msg(skb_put(skb, total_len), m, total_len);
 	if (error < 0) {
 		kfree_skb(skb);
-		goto error_put_sess_tun;
+		goto error_put_sess;
 	}
 
 	local_bh_disable();
 	l2tp_xmit_skb(session, skb, session->hdr_len);
 	local_bh_enable();
 
-	sock_put(ps->tunnel_sock);
 	sock_put(sk);
 
 	return total_len;
 
-error_put_sess_tun:
-	sock_put(ps->tunnel_sock);
 error_put_sess:
 	sock_put(sk);
 error:
@@ -369,10 +368,8 @@ error:
 static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
 {
 	struct sock *sk = (struct sock *) chan->private;
-	struct sock *sk_tun;
 	struct l2tp_session *session;
 	struct l2tp_tunnel *tunnel;
-	struct pppol2tp_session *ps;
 	int uhlen, headroom;
 
 	if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
@@ -383,13 +380,7 @@ static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
 	if (session == NULL)
 		goto abort;
 
-	ps = l2tp_session_priv(session);
-	sk_tun = ps->tunnel_sock;
-	if (sk_tun == NULL)
-		goto abort_put_sess;
-	tunnel = l2tp_sock_to_tunnel(sk_tun);
-	if (tunnel == NULL)
-		goto abort_put_sess;
+	tunnel = session->tunnel;
 
 	uhlen = (tunnel->encap == L2TP_ENCAPTYPE_UDP) ? sizeof(struct udphdr) : 0;
 	headroom = NET_SKB_PAD +
@@ -398,7 +389,7 @@ static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
 		   session->hdr_len +	/* L2TP header */
 		   2;			/* 2 bytes for PPP_ALLSTATIONS & PPP_UI */
 	if (skb_cow_head(skb, headroom))
-		goto abort_put_sess_tun;
+		goto abort_put_sess;
 
 	/* Setup PPP header */
 	__skb_push(skb, 2);
@@ -409,12 +400,10 @@ static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
 	l2tp_xmit_skb(session, skb, session->hdr_len);
 	local_bh_enable();
 
-	sock_put(sk_tun);
 	sock_put(sk);
+
 	return 1;
 
-abort_put_sess_tun:
-	sock_put(sk_tun);
 abort_put_sess:
 	sock_put(sk);
 abort:
@@ -431,17 +420,16 @@ abort:
  */
 static void pppol2tp_session_close(struct l2tp_session *session)
 {
-	struct pppol2tp_session *ps = l2tp_session_priv(session);
-	struct sock *sk = ps->sock;
-	struct socket *sock = sk->sk_socket;
+	struct sock *sk;
 
 	BUG_ON(session->magic != L2TP_SESSION_MAGIC);
 
-	if (sock)
-		inet_shutdown(sock, SEND_SHUTDOWN);
-
-	/* Don't let the session go away before our socket does */
-	l2tp_session_inc_refcount(session);
+	sk = pppol2tp_session_get_sock(session);
+	if (sk) {
+		if (sk->sk_socket)
+			inet_shutdown(sk->sk_socket, SEND_SHUTDOWN);
+		sock_put(sk);
+	}
 }
 
 /* Really kill the session socket. (Called from sock_put() if
@@ -461,6 +449,14 @@ static void pppol2tp_session_destruct(struct sock *sk)
 	}
 }
 
+static void pppol2tp_put_sk(struct rcu_head *head)
+{
+	struct pppol2tp_session *ps;
+
+	ps = container_of(head, typeof(*ps), rcu);
+	sock_put(ps->__sk);
+}
+
 /* Called when the PPPoX socket (session) is closed.
  */
 static int pppol2tp_release(struct socket *sock)
@@ -486,11 +482,23 @@ static int pppol2tp_release(struct socket *sock)
 
 	session = pppol2tp_sock_to_session(sk);
 
-	/* Purge any queued data */
 	if (session != NULL) {
-		__l2tp_session_unhash(session);
-		l2tp_session_queue_purge(session);
-		sock_put(sk);
+		struct pppol2tp_session *ps;
+
+		l2tp_session_delete(session);
+
+		ps = l2tp_session_priv(session);
+		mutex_lock(&ps->sk_lock);
+		ps->__sk = rcu_dereference_protected(ps->sk,
+						     lockdep_is_held(&ps->sk_lock));
+		RCU_INIT_POINTER(ps->sk, NULL);
+		mutex_unlock(&ps->sk_lock);
+		call_rcu(&ps->rcu, pppol2tp_put_sk);
+
+		/* Rely on the sock_put() call at the end of the function for
+		 * dropping the reference held by pppol2tp_sock_to_session().
+		 * The last reference will be dropped by pppol2tp_put_sk().
+		 */
 	}
 	release_sock(sk);
 
@@ -557,16 +565,46 @@ out:
 static void pppol2tp_show(struct seq_file *m, void *arg)
 {
 	struct l2tp_session *session = arg;
-	struct pppol2tp_session *ps = l2tp_session_priv(session);
+	struct sock *sk;
 
-	if (ps) {
-		struct pppox_sock *po = pppox_sk(ps->sock);
-		if (po)
-			seq_printf(m, "   interface %s\n", ppp_dev_name(&po->chan));
+	sk = pppol2tp_session_get_sock(session);
+	if (sk) {
+		struct pppox_sock *po = pppox_sk(sk);
+
+		seq_printf(m, "   interface %s\n", ppp_dev_name(&po->chan));
+		sock_put(sk);
 	}
 }
 #endif
 
+static void pppol2tp_session_init(struct l2tp_session *session)
+{
+	struct pppol2tp_session *ps;
+	struct dst_entry *dst;
+
+	session->recv_skb = pppol2tp_recv;
+	session->session_close = pppol2tp_session_close;
+#if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
+	session->show = pppol2tp_show;
+#endif
+
+	ps = l2tp_session_priv(session);
+	mutex_init(&ps->sk_lock);
+	ps->owner = current->pid;
+
+	/* If PMTU discovery was enabled, use the MTU that was discovered */
+	dst = sk_dst_get(session->tunnel->sock);
+	if (dst) {
+		u32 pmtu = dst_mtu(dst);
+
+		if (pmtu) {
+			session->mtu = pmtu - PPPOL2TP_HEADER_OVERHEAD;
+			session->mru = pmtu - PPPOL2TP_HEADER_OVERHEAD;
+		}
+		dst_release(dst);
+	}
+}
+
 /* connect() handler. Attach a PPPoX socket to a tunnel UDP socket
  */
 static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
@@ -578,7 +616,6 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
 	struct l2tp_session *session = NULL;
 	struct l2tp_tunnel *tunnel;
 	struct pppol2tp_session *ps;
-	struct dst_entry *dst;
 	struct l2tp_session_cfg cfg = { 0, };
 	int error = 0;
 	u32 tunnel_id, peer_tunnel_id;
@@ -688,7 +725,7 @@ 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);
@@ -696,13 +733,10 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
 		/* Using a pre-existing session is fine as long as it hasn't
 		 * been connected yet.
 		 */
-		if (ps->sock) {
-			error = -EEXIST;
-			goto end;
-		}
-
-		/* consistency checks */
-		if (ps->tunnel_sock != tunnel->sock) {
+		mutex_lock(&ps->sk_lock);
+		if (rcu_dereference_protected(ps->sk,
+					      lockdep_is_held(&ps->sk_lock))) {
+			mutex_unlock(&ps->sk_lock);
 			error = -EEXIST;
 			goto end;
 		}
@@ -718,35 +752,19 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
 			error = PTR_ERR(session);
 			goto end;
 		}
-	}
-
-	/* Associate session with its PPPoL2TP socket */
-	ps = l2tp_session_priv(session);
-	ps->owner	     = current->pid;
-	ps->sock	     = sk;
-	ps->tunnel_sock = tunnel->sock;
 
-	session->recv_skb	= pppol2tp_recv;
-	session->session_close	= pppol2tp_session_close;
-#if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
-	session->show		= pppol2tp_show;
-#endif
-
-	/* We need to know each time a skb is dropped from the reorder
-	 * queue.
-	 */
-	session->ref = pppol2tp_session_sock_hold;
-	session->deref = pppol2tp_session_sock_put;
-
-	/* If PMTU discovery was enabled, use the MTU that was discovered */
-	dst = sk_dst_get(tunnel->sock);
-	if (dst != NULL) {
-		u32 pmtu = dst_mtu(dst);
+		pppol2tp_session_init(session);
+		ps = l2tp_session_priv(session);
+		l2tp_session_inc_refcount(session);
 
-		if (pmtu != 0)
-			session->mtu = session->mru = pmtu -
-				PPPOL2TP_HEADER_OVERHEAD;
-		dst_release(dst);
+		mutex_lock(&ps->sk_lock);
+		error = l2tp_session_register(session, tunnel);
+		if (error < 0) {
+			mutex_unlock(&ps->sk_lock);
+			kfree(session);
+			goto end;
+		}
+		drop_refcnt = true;
 	}
 
 	/* Special case: if source & dest session_id == 0x0000, this
@@ -771,12 +789,23 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
 	po->chan.mtu	 = session->mtu;
 
 	error = ppp_register_net_channel(sock_net(sk), &po->chan);
-	if (error)
+	if (error) {
+		mutex_unlock(&ps->sk_lock);
 		goto end;
+	}
 
 out_no_ppp:
 	/* This is how we get the session context from the socket. */
 	sk->sk_user_data = session;
+	rcu_assign_pointer(ps->sk, sk);
+	mutex_unlock(&ps->sk_lock);
+
+	/* Keep the reference we've grabbed on the session: sk doesn't expect
+	 * the session to disappear. pppol2tp_session_destruct() is responsible
+	 * for dropping it.
+	 */
+	drop_refcnt = false;
+
 	sk->sk_state = PPPOX_CONNECTED;
 	l2tp_info(session, L2TP_MSG_CONTROL, "%s: created\n",
 		  session->name);
@@ -800,12 +829,11 @@ static int pppol2tp_session_create(struct net *net, struct l2tp_tunnel *tunnel,
 {
 	int error;
 	struct l2tp_session *session;
-	struct pppol2tp_session *ps;
 
 	/* Error if tunnel socket is not prepped */
 	if (!tunnel->sock) {
 		error = -ENOENT;
-		goto out;
+		goto err;
 	}
 
 	/* Default MTU values. */
@@ -820,18 +848,20 @@ static int pppol2tp_session_create(struct net *net, struct l2tp_tunnel *tunnel,
 				      peer_session_id, cfg);
 	if (IS_ERR(session)) {
 		error = PTR_ERR(session);
-		goto out;
+		goto err;
 	}
 
-	ps = l2tp_session_priv(session);
-	ps->tunnel_sock = tunnel->sock;
+	pppol2tp_session_init(session);
 
-	l2tp_info(session, L2TP_MSG_CONTROL, "%s: created\n",
-		  session->name);
+	error = l2tp_session_register(session, tunnel);
+	if (error < 0)
+		goto err_sess;
 
-	error = 0;
+	return 0;
 
-out:
+err_sess:
+	kfree(session);
+err:
 	return error;
 }
 
@@ -862,9 +892,7 @@ static int pppol2tp_getname(struct socket *sock, struct sockaddr *uaddr,
 		goto end;
 
 	pls = l2tp_session_priv(session);
-	tunnel = l2tp_sock_to_tunnel(pls->tunnel_sock);
-	if (tunnel == NULL)
-		goto end_put_sess;
+	tunnel = session->tunnel;
 
 	inet = inet_sk(tunnel->sock);
 	if ((tunnel->version == 2) && (tunnel->sock->sk_family == AF_INET)) {
@@ -944,8 +972,6 @@ static int pppol2tp_getname(struct socket *sock, struct sockaddr *uaddr,
 	*usockaddr_len = len;
 	error = 0;
 
-	sock_put(pls->tunnel_sock);
-end_put_sess:
 	sock_put(sk);
 end:
 	return error;
@@ -992,12 +1018,10 @@ static int pppol2tp_session_ioctl(struct l2tp_session *session,
 		 "%s: pppol2tp_session_ioctl(cmd=%#x, arg=%#lx)\n",
 		 session->name, cmd, arg);
 
-	sk = ps->sock;
+	sk = pppol2tp_session_get_sock(session);
 	if (!sk)
 		return -EBADR;
 
-	sock_hold(sk);
-
 	switch (cmd) {
 	case SIOCGIFMTU:
 		err = -ENXIO;
@@ -1143,13 +1167,11 @@ 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;
@@ -1188,7 +1210,6 @@ static int pppol2tp_ioctl(struct socket *sock, unsigned int cmd,
 	struct sock *sk = sock->sk;
 	struct l2tp_session *session;
 	struct l2tp_tunnel *tunnel;
-	struct pppol2tp_session *ps;
 	int err;
 
 	if (!sk)
@@ -1212,16 +1233,10 @@ static int pppol2tp_ioctl(struct socket *sock, unsigned int cmd,
 	/* Special case: if session's session_id is zero, treat ioctl as a
 	 * tunnel ioctl
 	 */
-	ps = l2tp_session_priv(session);
 	if ((session->session_id == 0) &&
 	    (session->peer_session_id == 0)) {
-		err = -EBADF;
-		tunnel = l2tp_sock_to_tunnel(ps->tunnel_sock);
-		if (tunnel == NULL)
-			goto end_put_sess;
-
+		tunnel = session->tunnel;
 		err = pppol2tp_tunnel_ioctl(tunnel, cmd, arg);
-		sock_put(ps->tunnel_sock);
 		goto end_put_sess;
 	}
 
@@ -1273,7 +1288,6 @@ static int pppol2tp_session_setsockopt(struct sock *sk,
 				       int optname, int val)
 {
 	int err = 0;
-	struct pppol2tp_session *ps = l2tp_session_priv(session);
 
 	switch (optname) {
 	case PPPOL2TP_SO_RECVSEQ:
@@ -1294,8 +1308,8 @@ static int pppol2tp_session_setsockopt(struct sock *sk,
 		}
 		session->send_seq = !!val;
 		{
-			struct sock *ssk      = ps->sock;
-			struct pppox_sock *po = pppox_sk(ssk);
+			struct pppox_sock *po = pppox_sk(sk);
+
 			po->chan.hdrlen = val ? PPPOL2TP_L2TP_HDR_SIZE_SEQ :
 				PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
 		}
@@ -1348,7 +1362,6 @@ static int pppol2tp_setsockopt(struct socket *sock, int level, int optname,
 	struct sock *sk = sock->sk;
 	struct l2tp_session *session;
 	struct l2tp_tunnel *tunnel;
-	struct pppol2tp_session *ps;
 	int val;
 	int err;
 
@@ -1373,20 +1386,14 @@ static int pppol2tp_setsockopt(struct socket *sock, int level, int optname,
 
 	/* Special case: if session_id == 0x0000, treat as operation on tunnel
 	 */
-	ps = l2tp_session_priv(session);
 	if ((session->session_id == 0) &&
 	    (session->peer_session_id == 0)) {
-		err = -EBADF;
-		tunnel = l2tp_sock_to_tunnel(ps->tunnel_sock);
-		if (tunnel == NULL)
-			goto end_put_sess;
-
+		tunnel = session->tunnel;
 		err = pppol2tp_tunnel_setsockopt(sk, tunnel, optname, val);
-		sock_put(ps->tunnel_sock);
-	} else
+	} else {
 		err = pppol2tp_session_setsockopt(sk, session, optname, val);
+	}
 
-end_put_sess:
 	sock_put(sk);
 end:
 	return err;
@@ -1474,7 +1481,6 @@ static int pppol2tp_getsockopt(struct socket *sock, int level, int optname,
 	struct l2tp_tunnel *tunnel;
 	int val, len;
 	int err;
-	struct pppol2tp_session *ps;
 
 	if (level != SOL_PPPOL2TP)
 		return -EINVAL;
@@ -1498,16 +1504,10 @@ static int pppol2tp_getsockopt(struct socket *sock, int level, int optname,
 		goto end;
 
 	/* Special case: if session_id == 0x0000, treat as operation on tunnel */
-	ps = l2tp_session_priv(session);
 	if ((session->session_id == 0) &&
 	    (session->peer_session_id == 0)) {
-		err = -EBADF;
-		tunnel = l2tp_sock_to_tunnel(ps->tunnel_sock);
-		if (tunnel == NULL)
-			goto end_put_sess;
-
+		tunnel = session->tunnel;
 		err = pppol2tp_tunnel_getsockopt(sk, tunnel, optname, &val);
-		sock_put(ps->tunnel_sock);
 		if (err)
 			goto end_put_sess;
 	} else {
@@ -1566,7 +1566,7 @@ 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) {
@@ -1634,8 +1634,9 @@ static void pppol2tp_seq_session_show(struct seq_file *m, void *v)
 {
 	struct l2tp_session *session = v;
 	struct l2tp_tunnel *tunnel = session->tunnel;
-	struct pppol2tp_session *ps = l2tp_session_priv(session);
-	struct pppox_sock *po = pppox_sk(ps->sock);
+	unsigned char state;
+	char user_data_ok;
+	struct sock *sk;
 	u32 ip = 0;
 	u16 port = 0;
 
@@ -1645,6 +1646,15 @@ static void pppol2tp_seq_session_show(struct seq_file *m, void *v)
 		port = ntohs(inet->inet_sport);
 	}
 
+	sk = pppol2tp_session_get_sock(session);
+	if (sk) {
+		state = sk->sk_state;
+		user_data_ok = (session == sk->sk_user_data) ? 'Y' : 'N';
+	} else {
+		state = 0;
+		user_data_ok = 'N';
+	}
+
 	seq_printf(m, "  SESSION '%s' %08X/%d %04X/%04X -> "
 		   "%04X/%04X %d %c\n",
 		   session->name, ip, port,
@@ -1652,9 +1662,7 @@ static void pppol2tp_seq_session_show(struct seq_file *m, void *v)
 		   session->session_id,
 		   tunnel->peer_tunnel_id,
 		   session->peer_session_id,
-		   ps->sock->sk_state,
-		   (session == ps->sock->sk_user_data) ?
-		   'Y' : 'N');
+		   state, user_data_ok);
 	seq_printf(m, "   %d/%d/%c/%c/%s %08x %u\n",
 		   session->mtu, session->mru,
 		   session->recv_seq ? 'R' : '-',
@@ -1671,8 +1679,12 @@ static void pppol2tp_seq_session_show(struct seq_file *m, void *v)
 		   atomic_long_read(&session->stats.rx_bytes),
 		   atomic_long_read(&session->stats.rx_errors));
 
-	if (po)
+	if (sk) {
+		struct pppox_sock *po = pppox_sk(sk);
+
 		seq_printf(m, "   interface %s\n", ppp_dev_name(&po->chan));
+		sock_put(sk);
+	}
 }
 
 static int pppol2tp_seq_show(struct seq_file *m, void *v)
@@ -1697,8 +1709,6 @@ 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);
 	}