1 files changed, 548 insertions, 229 deletions

diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c
index c708400fff4a..f9f0f16c41d1 100644
--- a/drivers/net/ppp/ppp_generic.c
+++ b/drivers/net/ppp/ppp_generic.c
@@ -1,13 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Generic PPP layer for Linux.
  *
  * Copyright 1999-2002 Paul Mackerras.
  *
- *  This program is free software; you can redistribute it and/or
- *  modify it under the terms of the GNU General Public License
- *  as published by the Free Software Foundation; either version
- *  2 of the License, or (at your option) any later version.
- *
  * The generic PPP layer handles the PPP network interfaces, the
  * /dev/ppp device, packet and VJ compression, and multilink.
  * It talks to PPP `channels' via the interface defined in
@@ -37,6 +33,7 @@
 #include <linux/ppp_channel.h>
 #include <linux/ppp-comp.h>
 #include <linux/skbuff.h>
+#include <linux/rculist.h>
 #include <linux/rtnetlink.h>
 #include <linux/if_arp.h>
 #include <linux/ip.h>
@@ -48,7 +45,8 @@
 #include <linux/mutex.h>
 #include <linux/slab.h>
 #include <linux/file.h>
-#include <asm/unaligned.h>
+#include <linux/unaligned.h>
+#include <net/netdev_lock.h>
 #include <net/slhc_vj.h>
 #include <linux/atomic.h>
 #include <linux/refcount.h>
@@ -73,6 +71,20 @@
 #define MPHDRLEN	6	/* multilink protocol header length */
 #define MPHDRLEN_SSN	4	/* ditto with short sequence numbers */
 
+#define PPP_PROTO_LEN	2
+#define PPP_LCP_HDRLEN	4
+
+/* The filter instructions generated by libpcap are constructed
+ * assuming a four-byte PPP header on each packet, where the last
+ * 2 bytes are the protocol field defined in the RFC and the first
+ * byte of the first 2 bytes indicates the direction.
+ * The second byte is currently unused, but we still need to initialize
+ * it to prevent crafted BPF programs from reading them which would
+ * cause reading of uninitialized data.
+ */
+#define PPP_FILTER_OUTBOUND_TAG 0x0100
+#define PPP_FILTER_INBOUND_TAG  0x0000
+
 /*
  * An instance of /dev/ppp can be associated with either a ppp
  * interface unit or a ppp channel.  In both cases, file->private_data
@@ -96,16 +108,9 @@ struct ppp_file {
 #define PF_TO_PPP(pf)		PF_TO_X(pf, struct ppp)
 #define PF_TO_CHANNEL(pf)	PF_TO_X(pf, struct channel)
 
-/*
- * Data structure to hold primary network stats for which
- * we want to use 64 bit storage.  Other network stats
- * are stored in dev->stats of the ppp strucute.
- */
-struct ppp_link_stats {
-	u64 rx_packets;
-	u64 tx_packets;
-	u64 rx_bytes;
-	u64 tx_bytes;
+struct ppp_xmit_recursion {
+	struct task_struct *owner;
+	local_lock_t bh_lock;
 };
 
 /*
@@ -121,7 +126,7 @@ struct ppp {
 	int		n_channels;	/* how many channels are attached 54 */
 	spinlock_t	rlock;		/* lock for receive side 58 */
 	spinlock_t	wlock;		/* lock for transmit side 5c */
-	int __percpu	*xmit_recursion; /* xmit recursion detect */
+	struct ppp_xmit_recursion __percpu *xmit_recursion; /* xmit recursion detect */
 	int		mru;		/* max receive unit 60 */
 	unsigned int	flags;		/* control bits 64 */
 	unsigned int	xstate;		/* transmit state bits 68 */
@@ -151,7 +156,6 @@ struct ppp {
 	struct bpf_prog *active_filter; /* filter for pkts to reset idle */
 #endif /* CONFIG_PPP_FILTER */
 	struct net	*ppp_net;	/* the net we belong to */
-	struct ppp_link_stats stats64;	/* 64 bit network stats */
 };
 
 /*
@@ -175,10 +179,12 @@ struct channel {
 	struct ppp_channel *chan;	/* public channel data structure */
 	struct rw_semaphore chan_sem;	/* protects `chan' during chan ioctl */
 	spinlock_t	downl;		/* protects `chan', file.xq dequeue */
-	struct ppp	*ppp;		/* ppp unit we're connected to */
+	struct ppp __rcu *ppp;		/* ppp unit we're connected to */
 	struct net	*chan_net;	/* the net channel belongs to */
+	netns_tracker	ns_tracker;
 	struct list_head clist;		/* link in list of channels per unit */
-	rwlock_t	upl;		/* protects `ppp' */
+	spinlock_t	upl;		/* protects `ppp' and 'bridge' */
+	struct channel __rcu *bridge;	/* "bridged" ppp channel */
 #ifdef CONFIG_PPP_MULTILINK
 	u8		avail;		/* flag used in multilink stuff */
 	u8		had_frag;	/* >= 1 fragments have been sent */
@@ -274,7 +280,7 @@ static void ppp_mp_insert(struct ppp *ppp, struct sk_buff *skb);
 static struct sk_buff *ppp_mp_reconstruct(struct ppp *ppp);
 static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb);
 #endif /* CONFIG_PPP_MULTILINK */
-static int ppp_set_compress(struct ppp *ppp, unsigned long arg);
+static int ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data);
 static void ppp_ccp_peek(struct ppp *ppp, struct sk_buff *skb, int inbound);
 static void ppp_ccp_closed(struct ppp *ppp);
 static struct compressor *find_compressor(int type);
@@ -287,7 +293,7 @@ static struct channel *ppp_find_channel(struct ppp_net *pn, int unit);
 static int ppp_connect_channel(struct channel *pch, int unit);
 static int ppp_disconnect_channel(struct channel *pch);
 static void ppp_destroy_channel(struct channel *pch);
-static int unit_get(struct idr *p, void *ptr);
+static int unit_get(struct idr *p, void *ptr, int min);
 static int unit_set(struct idr *p, void *ptr, int n);
 static void unit_put(struct idr *p, int n);
 static void *unit_find(struct idr *p, int n);
@@ -295,13 +301,13 @@ static void ppp_setup(struct net_device *dev);
 
 static const struct net_device_ops ppp_netdev_ops;
 
-static struct class *ppp_class;
+static const struct class ppp_class = {
+	.name = "ppp",
+};
 
 /* per net-namespace data */
 static inline struct ppp_net *ppp_pernet(struct net *net)
 {
-	BUG_ON(!net);
-
 	return net_generic(net, ppp_net_id);
 }
 
@@ -482,7 +488,7 @@ static ssize_t ppp_read(struct file *file, char __user *buf,
 	ret = -EFAULT;
 	iov.iov_base = buf;
 	iov.iov_len = count;
-	iov_iter_init(&to, READ, &iov, 1, count);
+	iov_iter_init(&to, ITER_DEST, &iov, 1, count);
 	if (skb_copy_datagram_iter(skb, 0, &to, skb->len))
 		goto outf;
 	ret = skb->len;
@@ -493,6 +499,15 @@ static ssize_t ppp_read(struct file *file, char __user *buf,
 	return ret;
 }
 
+static bool ppp_check_packet(struct sk_buff *skb, size_t count)
+{
+	/* LCP packets must include LCP header which 4 bytes long:
+	 * 1-byte code, 1-byte identifier, and 2-byte length.
+	 */
+	return get_unaligned_be16(skb->data) != PPP_LCP ||
+		count >= PPP_PROTO_LEN + PPP_LCP_HDRLEN;
+}
+
 static ssize_t ppp_write(struct file *file, const char __user *buf,
 			 size_t count, loff_t *ppos)
 {
@@ -502,6 +517,9 @@ static ssize_t ppp_write(struct file *file, const char __user *buf,
 
 	if (!pf)
 		return -ENXIO;
+	/* All PPP packets should start with the 2-byte protocol */
+	if (count < PPP_PROTO_LEN)
+		return -EINVAL;
 	ret = -ENOMEM;
 	skb = alloc_skb(count + pf->hdrlen, GFP_KERNEL);
 	if (!skb)
@@ -512,6 +530,11 @@ static ssize_t ppp_write(struct file *file, const char __user *buf,
 		kfree_skb(skb);
 		goto out;
 	}
+	ret = -EINVAL;
+	if (unlikely(!ppp_check_packet(skb, count))) {
+		kfree_skb(skb);
+		goto out;
+	}
 
 	switch (pf->kind) {
 	case INTERFACE:
@@ -558,36 +581,150 @@ static __poll_t ppp_poll(struct file *file, poll_table *wait)
 }
 
 #ifdef CONFIG_PPP_FILTER
-static int get_filter(void __user *arg, struct sock_filter **p)
+static struct bpf_prog *get_filter(struct sock_fprog *uprog)
+{
+	struct sock_fprog_kern fprog;
+	struct bpf_prog *res = NULL;
+	int err;
+
+	if (!uprog->len)
+		return NULL;
+
+	/* uprog->len is unsigned short, so no overflow here */
+	fprog.len = uprog->len;
+	fprog.filter = memdup_array_user(uprog->filter,
+					 uprog->len, sizeof(struct sock_filter));
+	if (IS_ERR(fprog.filter))
+		return ERR_CAST(fprog.filter);
+
+	err = bpf_prog_create(&res, &fprog);
+	kfree(fprog.filter);
+
+	return err ? ERR_PTR(err) : res;
+}
+
+static struct bpf_prog *ppp_get_filter(struct sock_fprog __user *p)
 {
 	struct sock_fprog uprog;
-	struct sock_filter *code = NULL;
-	int len;
 
-	if (copy_from_user(&uprog, arg, sizeof(uprog)))
-		return -EFAULT;
+	if (copy_from_user(&uprog, p, sizeof(struct sock_fprog)))
+		return ERR_PTR(-EFAULT);
+	return get_filter(&uprog);
+}
 
-	if (!uprog.len) {
-		*p = NULL;
-		return 0;
+#ifdef CONFIG_COMPAT
+struct sock_fprog32 {
+	unsigned short len;
+	compat_caddr_t filter;
+};
+
+#define PPPIOCSPASS32		_IOW('t', 71, struct sock_fprog32)
+#define PPPIOCSACTIVE32		_IOW('t', 70, struct sock_fprog32)
+
+static struct bpf_prog *compat_ppp_get_filter(struct sock_fprog32 __user *p)
+{
+	struct sock_fprog32 uprog32;
+	struct sock_fprog uprog;
+
+	if (copy_from_user(&uprog32, p, sizeof(struct sock_fprog32)))
+		return ERR_PTR(-EFAULT);
+	uprog.len = uprog32.len;
+	uprog.filter = compat_ptr(uprog32.filter);
+	return get_filter(&uprog);
+}
+#endif
+#endif
+
+/* Bridge one PPP channel to another.
+ * When two channels are bridged, ppp_input on one channel is redirected to
+ * the other's ops->start_xmit handler.
+ * In order to safely bridge channels we must reject channels which are already
+ * part of a bridge instance, or which form part of an existing unit.
+ * Once successfully bridged, each channel holds a reference on the other
+ * to prevent it being freed while the bridge is extant.
+ */
+static int ppp_bridge_channels(struct channel *pch, struct channel *pchb)
+{
+	spin_lock(&pch->upl);
+	if (rcu_dereference_protected(pch->ppp, lockdep_is_held(&pch->upl)) ||
+	    rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl))) {
+		spin_unlock(&pch->upl);
+		return -EALREADY;
+	}
+	refcount_inc(&pchb->file.refcnt);
+	rcu_assign_pointer(pch->bridge, pchb);
+	spin_unlock(&pch->upl);
+
+	spin_lock(&pchb->upl);
+	if (rcu_dereference_protected(pchb->ppp, lockdep_is_held(&pchb->upl)) ||
+	    rcu_dereference_protected(pchb->bridge, lockdep_is_held(&pchb->upl))) {
+		spin_unlock(&pchb->upl);
+		goto err_unset;
 	}
+	refcount_inc(&pch->file.refcnt);
+	rcu_assign_pointer(pchb->bridge, pch);
+	spin_unlock(&pchb->upl);
+
+	return 0;
+
+err_unset:
+	spin_lock(&pch->upl);
+	/* Re-read pch->bridge with upl held in case it was modified concurrently */
+	pchb = rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl));
+	RCU_INIT_POINTER(pch->bridge, NULL);
+	spin_unlock(&pch->upl);
+	synchronize_rcu();
 
-	len = uprog.len * sizeof(struct sock_filter);
-	code = memdup_user(uprog.filter, len);
-	if (IS_ERR(code))
-		return PTR_ERR(code);
+	if (pchb)
+		if (refcount_dec_and_test(&pchb->file.refcnt))
+			ppp_destroy_channel(pchb);
 
-	*p = code;
-	return uprog.len;
+	return -EALREADY;
+}
+
+static int ppp_unbridge_channels(struct channel *pch)
+{
+	struct channel *pchb, *pchbb;
+
+	spin_lock(&pch->upl);
+	pchb = rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl));
+	if (!pchb) {
+		spin_unlock(&pch->upl);
+		return -EINVAL;
+	}
+	RCU_INIT_POINTER(pch->bridge, NULL);
+	spin_unlock(&pch->upl);
+
+	/* Only modify pchb if phcb->bridge points back to pch.
+	 * If not, it implies that there has been a race unbridging (and possibly
+	 * even rebridging) pchb.  We should leave pchb alone to avoid either a
+	 * refcount underflow, or breaking another established bridge instance.
+	 */
+	spin_lock(&pchb->upl);
+	pchbb = rcu_dereference_protected(pchb->bridge, lockdep_is_held(&pchb->upl));
+	if (pchbb == pch)
+		RCU_INIT_POINTER(pchb->bridge, NULL);
+	spin_unlock(&pchb->upl);
+
+	synchronize_rcu();
+
+	if (pchbb == pch)
+		if (refcount_dec_and_test(&pch->file.refcnt))
+			ppp_destroy_channel(pch);
+
+	if (refcount_dec_and_test(&pchb->file.refcnt))
+		ppp_destroy_channel(pchb);
+
+	return 0;
 }
-#endif /* CONFIG_PPP_FILTER */
 
 static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
 	struct ppp_file *pf;
 	struct ppp *ppp;
 	int err = -EFAULT, val, val2, i;
-	struct ppp_idle idle;
+	struct ppp_idle32 idle32;
+	struct ppp_idle64 idle64;
 	struct npioctl npi;
 	int unit, cflags;
 	struct slcompress *vj;
@@ -616,8 +753,9 @@ static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	}
 
 	if (pf->kind == CHANNEL) {
-		struct channel *pch;
+		struct channel *pch, *pchb;
 		struct ppp_channel *chan;
+		struct ppp_net *pn;
 
 		pch = PF_TO_CHANNEL(pf);
 
@@ -632,6 +770,31 @@ static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 			err = ppp_disconnect_channel(pch);
 			break;
 
+		case PPPIOCBRIDGECHAN:
+			if (get_user(unit, p))
+				break;
+			err = -ENXIO;
+			pn = ppp_pernet(current->nsproxy->net_ns);
+			spin_lock_bh(&pn->all_channels_lock);
+			pchb = ppp_find_channel(pn, unit);
+			/* Hold a reference to prevent pchb being freed while
+			 * we establish the bridge.
+			 */
+			if (pchb)
+				refcount_inc(&pchb->file.refcnt);
+			spin_unlock_bh(&pn->all_channels_lock);
+			if (!pchb)
+				break;
+			err = ppp_bridge_channels(pch, pchb);
+			/* Drop earlier refcount now bridge establishment is complete */
+			if (refcount_dec_and_test(&pchb->file.refcnt))
+				ppp_destroy_channel(pchb);
+			break;
+
+		case PPPIOCUNBRIDGECHAN:
+			err = ppp_unbridge_channels(pch);
+			break;
+
 		default:
 			down_read(&pch->chan_sem);
 			chan = pch->chan;
@@ -683,9 +846,14 @@ static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 		break;
 
 	case PPPIOCSCOMPRESS:
-		err = ppp_set_compress(ppp, arg);
+	{
+		struct ppp_option_data data;
+		if (copy_from_user(&data, argp, sizeof(data)))
+			err = -EFAULT;
+		else
+			err = ppp_set_compress(ppp, &data);
 		break;
-
+	}
 	case PPPIOCGUNIT:
 		if (put_user(ppp->file.index, p))
 			break;
@@ -705,10 +873,18 @@ static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 		err = 0;
 		break;
 
-	case PPPIOCGIDLE:
-		idle.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
-		idle.recv_idle = (jiffies - ppp->last_recv) / HZ;
-		if (copy_to_user(argp, &idle, sizeof(idle)))
+	case PPPIOCGIDLE32:
+                idle32.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
+                idle32.recv_idle = (jiffies - ppp->last_recv) / HZ;
+                if (copy_to_user(argp, &idle32, sizeof(idle32)))
+			break;
+		err = 0;
+		break;
+
+	case PPPIOCGIDLE64:
+		idle64.xmit_idle = (jiffies - ppp->last_xmit) / HZ;
+		idle64.recv_idle = (jiffies - ppp->last_recv) / HZ;
+		if (copy_to_user(argp, &idle64, sizeof(idle64)))
 			break;
 		err = 0;
 		break;
@@ -757,55 +933,25 @@ static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 
 #ifdef CONFIG_PPP_FILTER
 	case PPPIOCSPASS:
-	{
-		struct sock_filter *code;
-
-		err = get_filter(argp, &code);
-		if (err >= 0) {
-			struct bpf_prog *pass_filter = NULL;
-			struct sock_fprog_kern fprog = {
-				.len = err,
-				.filter = code,
-			};
-
-			err = 0;
-			if (fprog.filter)
-				err = bpf_prog_create(&pass_filter, &fprog);
-			if (!err) {
-				ppp_lock(ppp);
-				if (ppp->pass_filter)
-					bpf_prog_destroy(ppp->pass_filter);
-				ppp->pass_filter = pass_filter;
-				ppp_unlock(ppp);
-			}
-			kfree(code);
-		}
-		break;
-	}
 	case PPPIOCSACTIVE:
 	{
-		struct sock_filter *code;
+		struct bpf_prog *filter = ppp_get_filter(argp);
+		struct bpf_prog **which;
 
-		err = get_filter(argp, &code);
-		if (err >= 0) {
-			struct bpf_prog *active_filter = NULL;
-			struct sock_fprog_kern fprog = {
-				.len = err,
-				.filter = code,
-			};
-
-			err = 0;
-			if (fprog.filter)
-				err = bpf_prog_create(&active_filter, &fprog);
-			if (!err) {
-				ppp_lock(ppp);
-				if (ppp->active_filter)
-					bpf_prog_destroy(ppp->active_filter);
-				ppp->active_filter = active_filter;
-				ppp_unlock(ppp);
-			}
-			kfree(code);
+		if (IS_ERR(filter)) {
+			err = PTR_ERR(filter);
+			break;
 		}
+		if (cmd == PPPIOCSPASS)
+			which = &ppp->pass_filter;
+		else
+			which = &ppp->active_filter;
+		ppp_lock(ppp);
+		if (*which)
+			bpf_prog_destroy(*which);
+		*which = filter;
+		ppp_unlock(ppp);
+		err = 0;
 		break;
 	}
 #endif /* CONFIG_PPP_FILTER */
@@ -831,6 +977,77 @@ out:
 	return err;
 }
 
+#ifdef CONFIG_COMPAT
+struct ppp_option_data32 {
+	compat_uptr_t		ptr;
+	u32			length;
+	compat_int_t		transmit;
+};
+#define PPPIOCSCOMPRESS32	_IOW('t', 77, struct ppp_option_data32)
+
+static long ppp_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct ppp_file *pf;
+	int err = -ENOIOCTLCMD;
+	void __user *argp = (void __user *)arg;
+
+	mutex_lock(&ppp_mutex);
+
+	pf = file->private_data;
+	if (pf && pf->kind == INTERFACE) {
+		struct ppp *ppp = PF_TO_PPP(pf);
+		switch (cmd) {
+#ifdef CONFIG_PPP_FILTER
+		case PPPIOCSPASS32:
+		case PPPIOCSACTIVE32:
+		{
+			struct bpf_prog *filter = compat_ppp_get_filter(argp);
+			struct bpf_prog **which;
+
+			if (IS_ERR(filter)) {
+				err = PTR_ERR(filter);
+				break;
+			}
+			if (cmd == PPPIOCSPASS32)
+				which = &ppp->pass_filter;
+			else
+				which = &ppp->active_filter;
+			ppp_lock(ppp);
+			if (*which)
+				bpf_prog_destroy(*which);
+			*which = filter;
+			ppp_unlock(ppp);
+			err = 0;
+			break;
+		}
+#endif /* CONFIG_PPP_FILTER */
+		case PPPIOCSCOMPRESS32:
+		{
+			struct ppp_option_data32 data32;
+			if (copy_from_user(&data32, argp, sizeof(data32))) {
+				err = -EFAULT;
+			} else {
+				struct ppp_option_data data = {
+					.ptr = compat_ptr(data32.ptr),
+					.length = data32.length,
+					.transmit = data32.transmit
+				};
+				err = ppp_set_compress(ppp, &data);
+			}
+			break;
+		}
+		}
+	}
+	mutex_unlock(&ppp_mutex);
+
+	/* all other commands have compatible arguments */
+	if (err == -ENOIOCTLCMD)
+		err = ppp_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
+
+	return err;
+}
+#endif
+
 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 			struct file *file, unsigned int cmd, unsigned long arg)
 {
@@ -899,11 +1116,16 @@ static const struct file_operations ppp_device_fops = {
 	.write		= ppp_write,
 	.poll		= ppp_poll,
 	.unlocked_ioctl	= ppp_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= ppp_compat_ioctl,
+#endif
 	.open		= ppp_open,
 	.release	= ppp_release,
 	.llseek		= noop_llseek,
 };
 
+static void ppp_nl_dellink(struct net_device *dev, struct list_head *head);
+
 static __net_init int ppp_init_net(struct net *net)
 {
 	struct ppp_net *pn = net_generic(net, ppp_net_id);
@@ -919,28 +1141,20 @@ static __net_init int ppp_init_net(struct net *net)
 	return 0;
 }
 
-static __net_exit void ppp_exit_net(struct net *net)
+static __net_exit void ppp_exit_rtnl_net(struct net *net,
+					 struct list_head *dev_to_kill)
 {
 	struct ppp_net *pn = net_generic(net, ppp_net_id);
-	struct net_device *dev;
-	struct net_device *aux;
 	struct ppp *ppp;
-	LIST_HEAD(list);
 	int id;
 
-	rtnl_lock();
-	for_each_netdev_safe(net, dev, aux) {
-		if (dev->netdev_ops == &ppp_netdev_ops)
-			unregister_netdevice_queue(dev, &list);
-	}
-
 	idr_for_each_entry(&pn->units_idr, ppp, id)
-		/* Skip devices already unregistered by previous loop */
-		if (!net_eq(dev_net(ppp->dev), net))
-			unregister_netdevice_queue(ppp->dev, &list);
+		ppp_nl_dellink(ppp->dev, dev_to_kill);
+}
 
-	unregister_netdevice_many(&list);
-	rtnl_unlock();
+static __net_exit void ppp_exit_net(struct net *net)
+{
+	struct ppp_net *pn = net_generic(net, ppp_net_id);
 
 	mutex_destroy(&pn->all_ppp_mutex);
 	idr_destroy(&pn->units_idr);
@@ -950,6 +1164,7 @@ static __net_exit void ppp_exit_net(struct net *net)
 
 static struct pernet_operations ppp_net_ops = {
 	.init = ppp_init_net,
+	.exit_rtnl = ppp_exit_rtnl_net,
 	.exit = ppp_exit_net,
 	.id   = &ppp_net_id,
 	.size = sizeof(struct ppp_net),
@@ -963,9 +1178,20 @@ static int ppp_unit_register(struct ppp *ppp, int unit, bool ifname_is_set)
 	mutex_lock(&pn->all_ppp_mutex);
 
 	if (unit < 0) {
-		ret = unit_get(&pn->units_idr, ppp);
+		ret = unit_get(&pn->units_idr, ppp, 0);
 		if (ret < 0)
 			goto err;
+		if (!ifname_is_set) {
+			while (1) {
+				snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ret);
+				if (!netdev_name_in_use(ppp->ppp_net, ppp->dev->name))
+					break;
+				unit_put(&pn->units_idr, ret);
+				ret = unit_get(&pn->units_idr, ppp, ret + 1);
+				if (ret < 0)
+					goto err;
+			}
+		}
 	} else {
 		/* Caller asked for a specific unit number. Fail with -EEXIST
 		 * if unavailable. For backward compatibility, return -EEXIST
@@ -1029,13 +1255,18 @@ static int ppp_dev_configure(struct net *src_net, struct net_device *dev,
 	spin_lock_init(&ppp->rlock);
 	spin_lock_init(&ppp->wlock);
 
-	ppp->xmit_recursion = alloc_percpu(int);
+	ppp->xmit_recursion = alloc_percpu(struct ppp_xmit_recursion);
 	if (!ppp->xmit_recursion) {
 		err = -ENOMEM;
 		goto err1;
 	}
-	for_each_possible_cpu(cpu)
-		(*per_cpu_ptr(ppp->xmit_recursion, cpu)) = 0;
+	for_each_possible_cpu(cpu) {
+		struct ppp_xmit_recursion *xmit_recursion;
+
+		xmit_recursion = per_cpu_ptr(ppp->xmit_recursion, cpu);
+		xmit_recursion->owner = NULL;
+		local_lock_init(&xmit_recursion->bh_lock);
+	}
 
 #ifdef CONFIG_PPP_MULTILINK
 	ppp->minseq = -1;
@@ -1077,10 +1308,13 @@ static int ppp_nl_validate(struct nlattr *tb[], struct nlattr *data[],
 	return 0;
 }
 
-static int ppp_nl_newlink(struct net *src_net, struct net_device *dev,
-			  struct nlattr *tb[], struct nlattr *data[],
+static int ppp_nl_newlink(struct net_device *dev,
+			  struct rtnl_newlink_params *params,
 			  struct netlink_ext_ack *extack)
 {
+	struct net *link_net = rtnl_newlink_link_net(params);
+	struct nlattr **data = params->data;
+	struct nlattr **tb = params->tb;
 	struct ppp_config conf = {
 		.unit = -1,
 		.ifname_is_set = true,
@@ -1114,10 +1348,10 @@ static int ppp_nl_newlink(struct net *src_net, struct net_device *dev,
 	 * the PPP unit identifer as suffix (i.e. ppp<unit_id>). This allows
 	 * userspace to infer the device name using to the PPPIOCGUNIT ioctl.
 	 */
-	if (!tb[IFLA_IFNAME])
+	if (!tb[IFLA_IFNAME] || !nla_len(tb[IFLA_IFNAME]) || !*(char *)nla_data(tb[IFLA_IFNAME]))
 		conf.ifname_is_set = false;
 
-	err = ppp_dev_configure(src_net, dev, &conf);
+	err = ppp_dev_configure(link_net, dev, &conf);
 
 out_unlock:
 	mutex_unlock(&ppp_mutex);
@@ -1146,7 +1380,7 @@ static struct net *ppp_nl_get_link_net(const struct net_device *dev)
 {
 	struct ppp *ppp = netdev_priv(dev);
 
-	return ppp->ppp_net;
+	return READ_ONCE(ppp->ppp_net);
 }
 
 static struct rtnl_link_ops ppp_link_ops __read_mostly = {
@@ -1185,11 +1419,9 @@ static int __init ppp_init(void)
 		goto out_net;
 	}
 
-	ppp_class = class_create(THIS_MODULE, "ppp");
-	if (IS_ERR(ppp_class)) {
-		err = PTR_ERR(ppp_class);
+	err = class_register(&ppp_class);
+	if (err)
 		goto out_chrdev;
-	}
 
 	err = rtnl_link_register(&ppp_link_ops);
 	if (err) {
@@ -1198,12 +1430,12 @@ static int __init ppp_init(void)
 	}
 
 	/* not a big deal if we fail here :-) */
-	device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
+	device_create(&ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
 
 	return 0;
 
 out_class:
-	class_destroy(ppp_class);
+	class_unregister(&ppp_class);
 out_chrdev:
 	unregister_chrdev(PPP_MAJOR, "ppp");
 out_net:
@@ -1260,11 +1492,11 @@ ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
 }
 
 static int
-ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
+ppp_net_siocdevprivate(struct net_device *dev, struct ifreq *ifr,
+		       void __user *addr, int cmd)
 {
 	struct ppp *ppp = netdev_priv(dev);
 	int err = -EFAULT;
-	void __user *addr = (void __user *) ifr->ifr_ifru.ifru_data;
 	struct ppp_stats stats;
 	struct ppp_comp_stats cstats;
 	char *vers;
@@ -1305,23 +1537,12 @@ ppp_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 static void
 ppp_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats64)
 {
-	struct ppp *ppp = netdev_priv(dev);
-
-	ppp_recv_lock(ppp);
-	stats64->rx_packets = ppp->stats64.rx_packets;
-	stats64->rx_bytes   = ppp->stats64.rx_bytes;
-	ppp_recv_unlock(ppp);
-
-	ppp_xmit_lock(ppp);
-	stats64->tx_packets = ppp->stats64.tx_packets;
-	stats64->tx_bytes   = ppp->stats64.tx_bytes;
-	ppp_xmit_unlock(ppp);
-
 	stats64->rx_errors        = dev->stats.rx_errors;
 	stats64->tx_errors        = dev->stats.tx_errors;
 	stats64->rx_dropped       = dev->stats.rx_dropped;
 	stats64->tx_dropped       = dev->stats.tx_dropped;
 	stats64->rx_length_errors = dev->stats.rx_length_errors;
+	dev_fetch_sw_netstats(stats64, dev->tstats);
 }
 
 static int ppp_dev_init(struct net_device *dev)
@@ -1368,15 +1589,40 @@ static void ppp_dev_priv_destructor(struct net_device *dev)
 		ppp_destroy_interface(ppp);
 }
 
+static int ppp_fill_forward_path(struct net_device_path_ctx *ctx,
+				 struct net_device_path *path)
+{
+	struct ppp *ppp = netdev_priv(ctx->dev);
+	struct ppp_channel *chan;
+	struct channel *pch;
+
+	if (ppp->flags & SC_MULTILINK)
+		return -EOPNOTSUPP;
+
+	pch = list_first_or_null_rcu(&ppp->channels, struct channel, clist);
+	if (!pch)
+		return -ENODEV;
+
+	chan = READ_ONCE(pch->chan);
+	if (!chan)
+		return -ENODEV;
+
+	if (!chan->ops->fill_forward_path)
+		return -EOPNOTSUPP;
+
+	return chan->ops->fill_forward_path(ctx, path, chan);
+}
+
 static const struct net_device_ops ppp_netdev_ops = {
 	.ndo_init	 = ppp_dev_init,
 	.ndo_uninit      = ppp_dev_uninit,
 	.ndo_start_xmit  = ppp_start_xmit,
-	.ndo_do_ioctl    = ppp_net_ioctl,
+	.ndo_siocdevprivate = ppp_net_siocdevprivate,
 	.ndo_get_stats64 = ppp_get_stats64,
+	.ndo_fill_forward_path = ppp_fill_forward_path,
 };
 
-static struct device_type ppp_type = {
+static const struct device_type ppp_type = {
 	.name = "ppp",
 };
 
@@ -1385,7 +1631,7 @@ static void ppp_setup(struct net_device *dev)
 	dev->netdev_ops = &ppp_netdev_ops;
 	SET_NETDEV_DEVTYPE(dev, &ppp_type);
 
-	dev->features |= NETIF_F_LLTX;
+	dev->lltx = true;
 
 	dev->hard_header_len = PPP_HDRLEN;
 	dev->mtu = PPP_MRU;
@@ -1394,6 +1640,7 @@ static void ppp_setup(struct net_device *dev)
 	dev->type = ARPHRD_PPP;
 	dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
 	dev->priv_destructor = ppp_dev_priv_destructor;
+	dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
 	netif_keep_dst(dev);
 }
 
@@ -1419,21 +1666,28 @@ static void __ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
 			netif_wake_queue(ppp->dev);
 		else
 			netif_stop_queue(ppp->dev);
+	} else {
+		kfree_skb(skb);
 	}
 	ppp_xmit_unlock(ppp);
 }
 
 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
 {
+	struct ppp_xmit_recursion *xmit_recursion;
+
 	local_bh_disable();
 
-	if (unlikely(*this_cpu_ptr(ppp->xmit_recursion)))
+	xmit_recursion = this_cpu_ptr(ppp->xmit_recursion);
+	if (xmit_recursion->owner == current)
 		goto err;
+	local_lock_nested_bh(&ppp->xmit_recursion->bh_lock);
+	xmit_recursion->owner = current;
 
-	(*this_cpu_ptr(ppp->xmit_recursion))++;
 	__ppp_xmit_process(ppp, skb);
-	(*this_cpu_ptr(ppp->xmit_recursion))--;
 
+	xmit_recursion->owner = NULL;
+	local_unlock_nested_bh(&ppp->xmit_recursion->bh_lock);
 	local_bh_enable();
 
 	return;
@@ -1490,7 +1744,6 @@ pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
 		 */
 		if (net_ratelimit())
 			netdev_err(ppp->dev, "ppp: compressor dropped pkt\n");
-		kfree_skb(skb);
 		consume_skb(new_skb);
 		new_skb = NULL;
 	}
@@ -1510,14 +1763,16 @@ ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
 	int len;
 	unsigned char *cp;
 
+	skb->dev = ppp->dev;
+
 	if (proto < 0x8000) {
 #ifdef CONFIG_PPP_FILTER
-		/* check if we should pass this packet */
-		/* the filter instructions are constructed assuming
-		   a four-byte PPP header on each packet */
-		*(u8 *)skb_push(skb, 2) = 1;
+		/* check if the packet passes the pass and active filters.
+		 * See comment for PPP_FILTER_OUTBOUND_TAG above.
+		 */
+		*(__be16 *)skb_push(skb, 2) = htons(PPP_FILTER_OUTBOUND_TAG);
 		if (ppp->pass_filter &&
-		    BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
+		    bpf_prog_run(ppp->pass_filter, skb) == 0) {
 			if (ppp->debug & 1)
 				netdev_printk(KERN_DEBUG, ppp->dev,
 					      "PPP: outbound frame "
@@ -1527,7 +1782,7 @@ ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
 		}
 		/* if this packet passes the active filter, record the time */
 		if (!(ppp->active_filter &&
-		      BPF_PROG_RUN(ppp->active_filter, skb) == 0))
+		      bpf_prog_run(ppp->active_filter, skb) == 0))
 			ppp->last_xmit = jiffies;
 		skb_pull(skb, 2);
 #else
@@ -1536,8 +1791,7 @@ ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
 #endif /* CONFIG_PPP_FILTER */
 	}
 
-	++ppp->stats64.tx_packets;
-	ppp->stats64.tx_bytes += skb->len - 2;
+	dev_sw_netstats_tx_add(ppp->dev, 1, skb->len - PPP_PROTO_LEN);
 
 	switch (proto) {
 	case PPP_IP:
@@ -1590,9 +1844,10 @@ ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
 					   "down - pkt dropped.\n");
 			goto drop;
 		}
-		skb = pad_compress_skb(ppp, skb);
-		if (!skb)
+		new_skb = pad_compress_skb(ppp, skb);
+		if (!new_skb)
 			goto drop;
+		skb = new_skb;
 	}
 
 	/*
@@ -1903,10 +2158,9 @@ static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
 #endif /* CONFIG_PPP_MULTILINK */
 
 /* Try to send data out on a channel */
-static void __ppp_channel_push(struct channel *pch)
+static void __ppp_channel_push(struct channel *pch, struct ppp *ppp)
 {
 	struct sk_buff *skb;
-	struct ppp *ppp;
 
 	spin_lock(&pch->downl);
 	if (pch->chan) {
@@ -1925,7 +2179,6 @@ static void __ppp_channel_push(struct channel *pch)
 	spin_unlock(&pch->downl);
 	/* see if there is anything from the attached unit to be sent */
 	if (skb_queue_empty(&pch->file.xq)) {
-		ppp = pch->ppp;
 		if (ppp)
 			__ppp_xmit_process(ppp, NULL);
 	}
@@ -1933,15 +2186,22 @@ static void __ppp_channel_push(struct channel *pch)
 
 static void ppp_channel_push(struct channel *pch)
 {
-	read_lock_bh(&pch->upl);
-	if (pch->ppp) {
-		(*this_cpu_ptr(pch->ppp->xmit_recursion))++;
-		__ppp_channel_push(pch);
-		(*this_cpu_ptr(pch->ppp->xmit_recursion))--;
+	struct ppp_xmit_recursion *xmit_recursion;
+	struct ppp *ppp;
+
+	rcu_read_lock_bh();
+	ppp = rcu_dereference_bh(pch->ppp);
+	if (ppp) {
+		xmit_recursion = this_cpu_ptr(ppp->xmit_recursion);
+		local_lock_nested_bh(&ppp->xmit_recursion->bh_lock);
+		xmit_recursion->owner = current;
+		__ppp_channel_push(pch, ppp);
+		xmit_recursion->owner = NULL;
+		local_unlock_nested_bh(&ppp->xmit_recursion->bh_lock);
 	} else {
-		__ppp_channel_push(pch);
+		__ppp_channel_push(pch, NULL);
 	}
-	read_unlock_bh(&pch->upl);
+	rcu_read_unlock_bh();
 }
 
 /*
@@ -2005,10 +2265,45 @@ static bool ppp_decompress_proto(struct sk_buff *skb)
 	return pskb_may_pull(skb, 2);
 }
 
+/* Attempt to handle a frame via. a bridged channel, if one exists.
+ * If the channel is bridged, the frame is consumed by the bridge.
+ * If not, the caller must handle the frame by normal recv mechanisms.
+ * Returns true if the frame is consumed, false otherwise.
+ */
+static bool ppp_channel_bridge_input(struct channel *pch, struct sk_buff *skb)
+{
+	struct channel *pchb;
+
+	rcu_read_lock();
+	pchb = rcu_dereference(pch->bridge);
+	if (!pchb)
+		goto out_rcu;
+
+	spin_lock_bh(&pchb->downl);
+	if (!pchb->chan) {
+		/* channel got unregistered */
+		kfree_skb(skb);
+		goto outl;
+	}
+
+	skb_scrub_packet(skb, !net_eq(pch->chan_net, pchb->chan_net));
+	if (!pchb->chan->ops->start_xmit(pchb->chan, skb))
+		kfree_skb(skb);
+
+outl:
+	spin_unlock_bh(&pchb->downl);
+out_rcu:
+	rcu_read_unlock();
+
+	/* If pchb is set then we've consumed the packet */
+	return !!pchb;
+}
+
 void
 ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
 {
 	struct channel *pch = chan->ppp;
+	struct ppp *ppp;
 	int proto;
 
 	if (!pch) {
@@ -2016,18 +2311,23 @@ ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
 		return;
 	}
 
-	read_lock_bh(&pch->upl);
+	/* If the channel is bridged, transmit via. bridge */
+	if (ppp_channel_bridge_input(pch, skb))
+		return;
+
+	rcu_read_lock_bh();
+	ppp = rcu_dereference_bh(pch->ppp);
 	if (!ppp_decompress_proto(skb)) {
 		kfree_skb(skb);
-		if (pch->ppp) {
-			++pch->ppp->dev->stats.rx_length_errors;
-			ppp_receive_error(pch->ppp);
+		if (ppp) {
+			++ppp->dev->stats.rx_length_errors;
+			ppp_receive_error(ppp);
 		}
 		goto done;
 	}
 
 	proto = PPP_PROTO(skb);
-	if (!pch->ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
+	if (!ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
 		/* put it on the channel queue */
 		skb_queue_tail(&pch->file.rq, skb);
 		/* drop old frames if queue too long */
@@ -2036,11 +2336,11 @@ ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
 			kfree_skb(skb);
 		wake_up_interruptible(&pch->file.rwait);
 	} else {
-		ppp_do_recv(pch->ppp, skb, pch);
+		ppp_do_recv(ppp, skb, pch);
 	}
 
 done:
-	read_unlock_bh(&pch->upl);
+	rcu_read_unlock_bh();
 }
 
 /* Put a 0-length skb in the receive queue as an error indication */
@@ -2049,20 +2349,22 @@ ppp_input_error(struct ppp_channel *chan, int code)
 {
 	struct channel *pch = chan->ppp;
 	struct sk_buff *skb;
+	struct ppp *ppp;
 
 	if (!pch)
 		return;
 
-	read_lock_bh(&pch->upl);
-	if (pch->ppp) {
+	rcu_read_lock_bh();
+	ppp = rcu_dereference_bh(pch->ppp);
+	if (ppp) {
 		skb = alloc_skb(0, GFP_ATOMIC);
 		if (skb) {
 			skb->len = 0;		/* probably unnecessary */
 			skb->cb[0] = code;
-			ppp_do_recv(pch->ppp, skb, pch);
+			ppp_do_recv(ppp, skb, pch);
 		}
 	}
-	read_unlock_bh(&pch->upl);
+	rcu_read_unlock_bh();
 }
 
 /*
@@ -2176,8 +2478,7 @@ ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
 		break;
 	}
 
-	++ppp->stats64.rx_packets;
-	ppp->stats64.rx_bytes += skb->len - 2;
+	dev_sw_netstats_rx_add(ppp->dev, skb->len - PPP_PROTO_LEN);
 
 	npi = proto_to_npindex(proto);
 	if (npi < 0) {
@@ -2194,16 +2495,15 @@ ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
 		/* network protocol frame - give it to the kernel */
 
 #ifdef CONFIG_PPP_FILTER
-		/* check if the packet passes the pass and active filters */
-		/* the filter instructions are constructed assuming
-		   a four-byte PPP header on each packet */
 		if (ppp->pass_filter || ppp->active_filter) {
 			if (skb_unclone(skb, GFP_ATOMIC))
 				goto err;
-
-			*(u8 *)skb_push(skb, 2) = 0;
+			/* Check if the packet passes the pass and active filters.
+			 * See comment for PPP_FILTER_INBOUND_TAG above.
+			 */
+			*(__be16 *)skb_push(skb, 2) = htons(PPP_FILTER_INBOUND_TAG);
 			if (ppp->pass_filter &&
-			    BPF_PROG_RUN(ppp->pass_filter, skb) == 0) {
+			    bpf_prog_run(ppp->pass_filter, skb) == 0) {
 				if (ppp->debug & 1)
 					netdev_printk(KERN_DEBUG, ppp->dev,
 						      "PPP: inbound frame "
@@ -2212,7 +2512,7 @@ ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
 				return;
 			}
 			if (!(ppp->active_filter &&
-			      BPF_PROG_RUN(ppp->active_filter, skb) == 0))
+			      bpf_prog_run(ppp->active_filter, skb) == 0))
 				ppp->last_recv = jiffies;
 			__skb_pull(skb, 2);
 		} else
@@ -2612,9 +2912,8 @@ int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
 
 	pn = ppp_pernet(net);
 
-	pch->ppp = NULL;
 	pch->chan = chan;
-	pch->chan_net = get_net(net);
+	pch->chan_net = get_net_track(net, &pch->ns_tracker, GFP_KERNEL);
 	chan->ppp = pch;
 	init_ppp_file(&pch->file, CHANNEL);
 	pch->file.hdrlen = chan->hdrlen;
@@ -2623,7 +2922,7 @@ int ppp_register_net_channel(struct net *net, struct ppp_channel *chan)
 #endif /* CONFIG_PPP_MULTILINK */
 	init_rwsem(&pch->chan_sem);
 	spin_lock_init(&pch->downl);
-	rwlock_init(&pch->upl);
+	spin_lock_init(&pch->upl);
 
 	spin_lock_bh(&pn->all_channels_lock);
 	pch->file.index = ++pn->last_channel_index;
@@ -2652,13 +2951,15 @@ int ppp_channel_index(struct ppp_channel *chan)
 int ppp_unit_number(struct ppp_channel *chan)
 {
 	struct channel *pch = chan->ppp;
+	struct ppp *ppp;
 	int unit = -1;
 
 	if (pch) {
-		read_lock_bh(&pch->upl);
-		if (pch->ppp)
-			unit = pch->ppp->file.index;
-		read_unlock_bh(&pch->upl);
+		rcu_read_lock();
+		ppp = rcu_dereference(pch->ppp);
+		if (ppp)
+			unit = ppp->file.index;
+		rcu_read_unlock();
 	}
 	return unit;
 }
@@ -2670,12 +2971,14 @@ char *ppp_dev_name(struct ppp_channel *chan)
 {
 	struct channel *pch = chan->ppp;
 	char *name = NULL;
+	struct ppp *ppp;
 
 	if (pch) {
-		read_lock_bh(&pch->upl);
-		if (pch->ppp && pch->ppp->dev)
-			name = pch->ppp->dev->name;
-		read_unlock_bh(&pch->upl);
+		rcu_read_lock();
+		ppp = rcu_dereference(pch->ppp);
+		if (ppp && ppp->dev)
+			name = ppp->dev->name;
+		rcu_read_unlock();
 	}
 	return name;
 }
@@ -2697,12 +3000,12 @@ ppp_unregister_channel(struct ppp_channel *chan)
 	chan->ppp = NULL;
 
 	/*
-	 * This ensures that we have returned from any calls into the
+	 * This ensures that we have returned from any calls into
 	 * the channel's start_xmit or ioctl routine before we proceed.
 	 */
 	down_write(&pch->chan_sem);
 	spin_lock_bh(&pch->downl);
-	pch->chan = NULL;
+	WRITE_ONCE(pch->chan, NULL);
 	spin_unlock_bh(&pch->downl);
 	up_write(&pch->chan_sem);
 	ppp_disconnect_channel(pch);
@@ -2712,8 +3015,11 @@ ppp_unregister_channel(struct ppp_channel *chan)
 	list_del(&pch->list);
 	spin_unlock_bh(&pn->all_channels_lock);
 
+	ppp_unbridge_channels(pch);
+
 	pch->file.dead = 1;
 	wake_up_interruptible(&pch->file.rwait);
+
 	if (refcount_dec_and_test(&pch->file.refcnt))
 		ppp_destroy_channel(pch);
 }
@@ -2738,24 +3044,20 @@ ppp_output_wakeup(struct ppp_channel *chan)
 
 /* Process the PPPIOCSCOMPRESS ioctl. */
 static int
-ppp_set_compress(struct ppp *ppp, unsigned long arg)
+ppp_set_compress(struct ppp *ppp, struct ppp_option_data *data)
 {
-	int err;
+	int err = -EFAULT;
 	struct compressor *cp, *ocomp;
-	struct ppp_option_data data;
 	void *state, *ostate;
 	unsigned char ccp_option[CCP_MAX_OPTION_LENGTH];
 
-	err = -EFAULT;
-	if (copy_from_user(&data, (void __user *) arg, sizeof(data)))
+	if (data->length > CCP_MAX_OPTION_LENGTH)
 		goto out;
-	if (data.length > CCP_MAX_OPTION_LENGTH)
-		goto out;
-	if (copy_from_user(ccp_option, (void __user *) data.ptr, data.length))
+	if (copy_from_user(ccp_option, data->ptr, data->length))
 		goto out;
 
 	err = -EINVAL;
-	if (data.length < 2 || ccp_option[1] < 2 || ccp_option[1] > data.length)
+	if (data->length < 2 || ccp_option[1] < 2 || ccp_option[1] > data->length)
 		goto out;
 
 	cp = try_then_request_module(
@@ -2765,8 +3067,8 @@ ppp_set_compress(struct ppp *ppp, unsigned long arg)
 		goto out;
 
 	err = -ENOBUFS;
-	if (data.transmit) {
-		state = cp->comp_alloc(ccp_option, data.length);
+	if (data->transmit) {
+		state = cp->comp_alloc(ccp_option, data->length);
 		if (state) {
 			ppp_xmit_lock(ppp);
 			ppp->xstate &= ~SC_COMP_RUN;
@@ -2784,7 +3086,7 @@ ppp_set_compress(struct ppp *ppp, unsigned long arg)
 			module_put(cp->owner);
 
 	} else {
-		state = cp->decomp_alloc(ccp_option, data.length);
+		state = cp->decomp_alloc(ccp_option, data->length);
 		if (state) {
 			ppp_recv_lock(ppp);
 			ppp->rstate &= ~SC_DECOMP_RUN;
@@ -3007,14 +3309,25 @@ static void
 ppp_get_stats(struct ppp *ppp, struct ppp_stats *st)
 {
 	struct slcompress *vj = ppp->vj;
+	int cpu;
 
 	memset(st, 0, sizeof(*st));
-	st->p.ppp_ipackets = ppp->stats64.rx_packets;
+	for_each_possible_cpu(cpu) {
+		struct pcpu_sw_netstats *p = per_cpu_ptr(ppp->dev->tstats, cpu);
+		u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
+
+		rx_packets = u64_stats_read(&p->rx_packets);
+		rx_bytes = u64_stats_read(&p->rx_bytes);
+		tx_packets = u64_stats_read(&p->tx_packets);
+		tx_bytes = u64_stats_read(&p->tx_bytes);
+
+		st->p.ppp_ipackets += rx_packets;
+		st->p.ppp_ibytes += rx_bytes;
+		st->p.ppp_opackets += tx_packets;
+		st->p.ppp_obytes += tx_bytes;
+	}
 	st->p.ppp_ierrors = ppp->dev->stats.rx_errors;
-	st->p.ppp_ibytes = ppp->stats64.rx_bytes;
-	st->p.ppp_opackets = ppp->stats64.tx_packets;
 	st->p.ppp_oerrors = ppp->dev->stats.tx_errors;
-	st->p.ppp_obytes = ppp->stats64.tx_bytes;
 	if (!vj)
 		return;
 	st->vj.vjs_packets = vj->sls_o_compressed + vj->sls_o_uncompressed;
@@ -3188,9 +3501,10 @@ ppp_connect_channel(struct channel *pch, int unit)
 	ppp = ppp_find_unit(pn, unit);
 	if (!ppp)
 		goto out;
-	write_lock_bh(&pch->upl);
+	spin_lock(&pch->upl);
 	ret = -EINVAL;
-	if (pch->ppp)
+	if (rcu_dereference_protected(pch->ppp, lockdep_is_held(&pch->upl)) ||
+	    rcu_dereference_protected(pch->bridge, lockdep_is_held(&pch->upl)))
 		goto outl;
 
 	ppp_lock(ppp);
@@ -3202,21 +3516,25 @@ ppp_connect_channel(struct channel *pch, int unit)
 		ret = -ENOTCONN;
 		goto outl;
 	}
+	if (pch->chan->direct_xmit)
+		ppp->dev->priv_flags |= IFF_NO_QUEUE;
+	else
+		ppp->dev->priv_flags &= ~IFF_NO_QUEUE;
 	spin_unlock_bh(&pch->downl);
 	if (pch->file.hdrlen > ppp->file.hdrlen)
 		ppp->file.hdrlen = pch->file.hdrlen;
 	hdrlen = pch->file.hdrlen + 2;	/* for protocol bytes */
 	if (hdrlen > ppp->dev->hard_header_len)
 		ppp->dev->hard_header_len = hdrlen;
-	list_add_tail(&pch->clist, &ppp->channels);
+	list_add_tail_rcu(&pch->clist, &ppp->channels);
 	++ppp->n_channels;
-	pch->ppp = ppp;
+	rcu_assign_pointer(pch->ppp, ppp);
 	refcount_inc(&ppp->file.refcnt);
 	ppp_unlock(ppp);
 	ret = 0;
 
  outl:
-	write_unlock_bh(&pch->upl);
+	spin_unlock(&pch->upl);
  out:
 	mutex_unlock(&pn->all_ppp_mutex);
 	return ret;
@@ -3231,17 +3549,17 @@ ppp_disconnect_channel(struct channel *pch)
 	struct ppp *ppp;
 	int err = -EINVAL;
 
-	write_lock_bh(&pch->upl);
-	ppp = pch->ppp;
-	pch->ppp = NULL;
-	write_unlock_bh(&pch->upl);
+	spin_lock(&pch->upl);
+	ppp = rcu_replace_pointer(pch->ppp, NULL, lockdep_is_held(&pch->upl));
+	spin_unlock(&pch->upl);
 	if (ppp) {
 		/* remove it from the ppp unit's list */
 		ppp_lock(ppp);
-		list_del(&pch->clist);
+		list_del_rcu(&pch->clist);
 		if (--ppp->n_channels == 0)
 			wake_up_interruptible(&ppp->file.rwait);
 		ppp_unlock(ppp);
+		synchronize_net();
 		if (refcount_dec_and_test(&ppp->file.refcnt))
 			ppp_destroy_interface(ppp);
 		err = 0;
@@ -3254,7 +3572,7 @@ ppp_disconnect_channel(struct channel *pch)
  */
 static void ppp_destroy_channel(struct channel *pch)
 {
-	put_net(pch->chan_net);
+	put_net_track(pch->chan_net, &pch->ns_tracker);
 	pch->chan_net = NULL;
 
 	atomic_dec(&channel_count);
@@ -3276,8 +3594,8 @@ static void __exit ppp_cleanup(void)
 		pr_err("PPP: removing module but units remain!\n");
 	rtnl_link_unregister(&ppp_link_ops);
 	unregister_chrdev(PPP_MAJOR, "ppp");
-	device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
-	class_destroy(ppp_class);
+	device_destroy(&ppp_class, MKDEV(PPP_MAJOR, 0));
+	class_unregister(&ppp_class);
 	unregister_pernet_device(&ppp_net_ops);
 }
 
@@ -3298,9 +3616,9 @@ static int unit_set(struct idr *p, void *ptr, int n)
 }
 
 /* get new free unit number and associate pointer with it */
-static int unit_get(struct idr *p, void *ptr)
+static int unit_get(struct idr *p, void *ptr, int min)
 {
-	return idr_alloc(p, ptr, 0, 0, GFP_KERNEL);
+	return idr_alloc(p, ptr, min, 0, GFP_KERNEL);
 }
 
 /* put unit number back to a pool */
@@ -3331,6 +3649,7 @@ EXPORT_SYMBOL(ppp_input_error);
 EXPORT_SYMBOL(ppp_output_wakeup);
 EXPORT_SYMBOL(ppp_register_compressor);
 EXPORT_SYMBOL(ppp_unregister_compressor);
+MODULE_DESCRIPTION("Generic PPP layer driver");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS_CHARDEV(PPP_MAJOR, 0);
 MODULE_ALIAS_RTNL_LINK("ppp");