1 files changed, 178 insertions, 113 deletions

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 1572878c3403..7a3ab3427369 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -209,6 +209,9 @@ struct tun_struct {
 	struct tun_prog __rcu *steering_prog;
 	struct tun_prog __rcu *filter_prog;
 	struct ethtool_link_ksettings link_ksettings;
+	/* init args */
+	struct file *file;
+	struct ifreq *ifr;
 };
 
 struct veth {
@@ -216,6 +219,9 @@ struct veth {
 	__be16 h_vlan_TCI;
 };
 
+static void tun_flow_init(struct tun_struct *tun);
+static void tun_flow_uninit(struct tun_struct *tun);
+
 static int tun_napi_receive(struct napi_struct *napi, int budget)
 {
 	struct tun_file *tfile = container_of(napi, struct tun_file, napi);
@@ -262,12 +268,17 @@ static void tun_napi_init(struct tun_struct *tun, struct tun_file *tfile,
 	tfile->napi_enabled = napi_en;
 	tfile->napi_frags_enabled = napi_en && napi_frags;
 	if (napi_en) {
-		netif_tx_napi_add(tun->dev, &tfile->napi, tun_napi_poll,
-				  NAPI_POLL_WEIGHT);
+		netif_napi_add_tx(tun->dev, &tfile->napi, tun_napi_poll);
 		napi_enable(&tfile->napi);
 	}
 }
 
+static void tun_napi_enable(struct tun_file *tfile)
+{
+	if (tfile->napi_enabled)
+		napi_enable(&tfile->napi);
+}
+
 static void tun_napi_disable(struct tun_file *tfile)
 {
 	if (tfile->napi_enabled)
@@ -629,7 +640,8 @@ static void __tun_detach(struct tun_file *tfile, bool clean)
 	tun = rtnl_dereference(tfile->tun);
 
 	if (tun && clean) {
-		tun_napi_disable(tfile);
+		if (!tfile->detached)
+			tun_napi_disable(tfile);
 		tun_napi_del(tfile);
 	}
 
@@ -648,8 +660,10 @@ static void __tun_detach(struct tun_file *tfile, bool clean)
 		if (clean) {
 			RCU_INIT_POINTER(tfile->tun, NULL);
 			sock_put(&tfile->sk);
-		} else
+		} else {
 			tun_disable_queue(tun, tfile);
+			tun_napi_disable(tfile);
+		}
 
 		synchronize_net();
 		tun_flow_delete_by_queue(tun, tun->numqueues + 1);
@@ -722,6 +736,7 @@ static void tun_detach_all(struct net_device *dev)
 		sock_put(&tfile->sk);
 	}
 	list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) {
+		tun_napi_del(tfile);
 		tun_enable_queue(tfile);
 		tun_queue_purge(tfile);
 		xdp_rxq_info_unreg(&tfile->xdp_rxq);
@@ -802,6 +817,7 @@ static int tun_attach(struct tun_struct *tun, struct file *file,
 
 	if (tfile->detached) {
 		tun_enable_queue(tfile);
+		tun_napi_enable(tfile);
 	} else {
 		sock_hold(&tfile->sk);
 		tun_napi_init(tun, tfile, napi, napi_frags);
@@ -953,6 +969,49 @@ static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
 
 static const struct ethtool_ops tun_ethtool_ops;
 
+static int tun_net_init(struct net_device *dev)
+{
+	struct tun_struct *tun = netdev_priv(dev);
+	struct ifreq *ifr = tun->ifr;
+	int err;
+
+	dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
+	if (!dev->tstats)
+		return -ENOMEM;
+
+	spin_lock_init(&tun->lock);
+
+	err = security_tun_dev_alloc_security(&tun->security);
+	if (err < 0) {
+		free_percpu(dev->tstats);
+		return err;
+	}
+
+	tun_flow_init(tun);
+
+	dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
+			   TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
+			   NETIF_F_HW_VLAN_STAG_TX;
+	dev->features = dev->hw_features | NETIF_F_LLTX;
+	dev->vlan_features = dev->features &
+			     ~(NETIF_F_HW_VLAN_CTAG_TX |
+			       NETIF_F_HW_VLAN_STAG_TX);
+
+	tun->flags = (tun->flags & ~TUN_FEATURES) |
+		      (ifr->ifr_flags & TUN_FEATURES);
+
+	INIT_LIST_HEAD(&tun->disabled);
+	err = tun_attach(tun, tun->file, false, ifr->ifr_flags & IFF_NAPI,
+			 ifr->ifr_flags & IFF_NAPI_FRAGS, false);
+	if (err < 0) {
+		tun_flow_uninit(tun);
+		security_tun_dev_free_security(tun->security);
+		free_percpu(dev->tstats);
+		return err;
+	}
+	return 0;
+}
+
 /* Net device detach from fd. */
 static void tun_net_uninit(struct net_device *dev)
 {
@@ -1009,6 +1068,7 @@ static unsigned int run_ebpf_filter(struct tun_struct *tun,
 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct tun_struct *tun = netdev_priv(dev);
+	enum skb_drop_reason drop_reason;
 	int txq = skb->queue_mapping;
 	struct netdev_queue *queue;
 	struct tun_file *tfile;
@@ -1018,8 +1078,10 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 	tfile = rcu_dereference(tun->tfiles[txq]);
 
 	/* Drop packet if interface is not attached */
-	if (!tfile)
+	if (!tfile) {
+		drop_reason = SKB_DROP_REASON_DEV_READY;
 		goto drop;
+	}
 
 	if (!rcu_dereference(tun->steering_prog))
 		tun_automq_xmit(tun, skb);
@@ -1029,19 +1091,32 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 	/* Drop if the filter does not like it.
 	 * This is a noop if the filter is disabled.
 	 * Filter can be enabled only for the TAP devices. */
-	if (!check_filter(&tun->txflt, skb))
+	if (!check_filter(&tun->txflt, skb)) {
+		drop_reason = SKB_DROP_REASON_TAP_TXFILTER;
 		goto drop;
+	}
 
 	if (tfile->socket.sk->sk_filter &&
-	    sk_filter(tfile->socket.sk, skb))
+	    sk_filter(tfile->socket.sk, skb)) {
+		drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
 		goto drop;
+	}
 
 	len = run_ebpf_filter(tun, skb, len);
-	if (len == 0 || pskb_trim(skb, len))
+	if (len == 0) {
+		drop_reason = SKB_DROP_REASON_TAP_FILTER;
 		goto drop;
+	}
 
-	if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC)))
+	if (pskb_trim(skb, len)) {
+		drop_reason = SKB_DROP_REASON_NOMEM;
 		goto drop;
+	}
+
+	if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC))) {
+		drop_reason = SKB_DROP_REASON_SKB_UCOPY_FAULT;
+		goto drop;
+	}
 
 	skb_tx_timestamp(skb);
 
@@ -1052,12 +1127,14 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 
 	nf_reset_ct(skb);
 
-	if (ptr_ring_produce(&tfile->tx_ring, skb))
+	if (ptr_ring_produce(&tfile->tx_ring, skb)) {
+		drop_reason = SKB_DROP_REASON_FULL_RING;
 		goto drop;
+	}
 
 	/* NETIF_F_LLTX requires to do our own update of trans_start */
 	queue = netdev_get_tx_queue(dev, txq);
-	queue->trans_start = jiffies;
+	txq_trans_cond_update(queue);
 
 	/* Notify and wake up reader process */
 	if (tfile->flags & TUN_FASYNC)
@@ -1068,9 +1145,9 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 	return NETDEV_TX_OK;
 
 drop:
-	atomic_long_inc(&dev->tx_dropped);
+	dev_core_stats_tx_dropped_inc(dev);
 	skb_tx_error(skb);
-	kfree_skb(skb);
+	kfree_skb_reason(skb, drop_reason);
 	rcu_read_unlock();
 	return NET_XMIT_DROP;
 }
@@ -1169,6 +1246,7 @@ static int tun_net_change_carrier(struct net_device *dev, bool new_carrier)
 }
 
 static const struct net_device_ops tun_netdev_ops = {
+	.ndo_init		= tun_net_init,
 	.ndo_uninit		= tun_net_uninit,
 	.ndo_open		= tun_net_open,
 	.ndo_stop		= tun_net_close,
@@ -1223,7 +1301,7 @@ resample:
 		void *frame = tun_xdp_to_ptr(xdp);
 
 		if (__ptr_ring_produce(&tfile->tx_ring, frame)) {
-			atomic_long_inc(&dev->tx_dropped);
+			dev_core_stats_tx_dropped_inc(dev);
 			break;
 		}
 		nxmit++;
@@ -1252,6 +1330,7 @@ static int tun_xdp_tx(struct net_device *dev, struct xdp_buff *xdp)
 }
 
 static const struct net_device_ops tap_netdev_ops = {
+	.ndo_init		= tun_net_init,
 	.ndo_uninit		= tun_net_uninit,
 	.ndo_open		= tun_net_open,
 	.ndo_stop		= tun_net_close,
@@ -1292,7 +1371,7 @@ static void tun_flow_uninit(struct tun_struct *tun)
 #define MAX_MTU 65535
 
 /* Initialize net device. */
-static void tun_net_init(struct net_device *dev)
+static void tun_net_initialize(struct net_device *dev)
 {
 	struct tun_struct *tun = netdev_priv(dev);
 
@@ -1380,7 +1459,8 @@ static struct sk_buff *tun_napi_alloc_frags(struct tun_file *tfile,
 	int err;
 	int i;
 
-	if (it->nr_segs > MAX_SKB_FRAGS + 1)
+	if (it->nr_segs > MAX_SKB_FRAGS + 1 ||
+	    len > (ETH_MAX_MTU - NET_SKB_PAD - NET_IP_ALIGN))
 		return ERR_PTR(-EMSGSIZE);
 
 	local_bh_disable();
@@ -1551,13 +1631,13 @@ static int tun_xdp_act(struct tun_struct *tun, struct bpf_prog *xdp_prog,
 	case XDP_PASS:
 		break;
 	default:
-		bpf_warn_invalid_xdp_action(act);
+		bpf_warn_invalid_xdp_action(tun->dev, xdp_prog, act);
 		fallthrough;
 	case XDP_ABORTED:
 		trace_xdp_exception(tun->dev, xdp_prog, act);
 		fallthrough;
 	case XDP_DROP:
-		atomic_long_inc(&tun->dev->rx_dropped);
+		dev_core_stats_rx_dropped_inc(tun->dev);
 		break;
 	}
 
@@ -1666,6 +1746,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 	u32 rxhash = 0;
 	int skb_xdp = 1;
 	bool frags = tun_napi_frags_enabled(tfile);
+	enum skb_drop_reason drop_reason;
 
 	if (!(tun->flags & IFF_NO_PI)) {
 		if (len < sizeof(pi))
@@ -1727,7 +1808,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 		 */
 		skb = tun_build_skb(tun, tfile, from, &gso, len, &skb_xdp);
 		if (IS_ERR(skb)) {
-			atomic_long_inc(&tun->dev->rx_dropped);
+			dev_core_stats_rx_dropped_inc(tun->dev);
 			return PTR_ERR(skb);
 		}
 		if (!skb)
@@ -1756,7 +1837,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 
 		if (IS_ERR(skb)) {
 			if (PTR_ERR(skb) != -EAGAIN)
-				atomic_long_inc(&tun->dev->rx_dropped);
+				dev_core_stats_rx_dropped_inc(tun->dev);
 			if (frags)
 				mutex_unlock(&tfile->napi_mutex);
 			return PTR_ERR(skb);
@@ -1769,9 +1850,10 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 
 		if (err) {
 			err = -EFAULT;
+			drop_reason = SKB_DROP_REASON_SKB_UCOPY_FAULT;
 drop:
-			atomic_long_inc(&tun->dev->rx_dropped);
-			kfree_skb(skb);
+			dev_core_stats_rx_dropped_inc(tun->dev);
+			kfree_skb_reason(skb, drop_reason);
 			if (frags) {
 				tfile->napi.skb = NULL;
 				mutex_unlock(&tfile->napi_mutex);
@@ -1805,7 +1887,7 @@ drop:
 				pi.proto = htons(ETH_P_IPV6);
 				break;
 			default:
-				atomic_long_inc(&tun->dev->rx_dropped);
+				dev_core_stats_rx_dropped_inc(tun->dev);
 				kfree_skb(skb);
 				return -EINVAL;
 			}
@@ -1818,6 +1900,7 @@ drop:
 	case IFF_TAP:
 		if (frags && !pskb_may_pull(skb, ETH_HLEN)) {
 			err = -ENOMEM;
+			drop_reason = SKB_DROP_REASON_HDR_TRUNC;
 			goto drop;
 		}
 		skb->protocol = eth_type_trans(skb, tun->dev);
@@ -1871,6 +1954,7 @@ drop:
 	if (unlikely(!(tun->dev->flags & IFF_UP))) {
 		err = -EIO;
 		rcu_read_unlock();
+		drop_reason = SKB_DROP_REASON_DEV_READY;
 		goto drop;
 	}
 
@@ -1883,17 +1967,25 @@ drop:
 					  skb_headlen(skb));
 
 		if (unlikely(headlen > skb_headlen(skb))) {
-			atomic_long_inc(&tun->dev->rx_dropped);
+			WARN_ON_ONCE(1);
+			err = -ENOMEM;
+			dev_core_stats_rx_dropped_inc(tun->dev);
+napi_busy:
 			napi_free_frags(&tfile->napi);
 			rcu_read_unlock();
 			mutex_unlock(&tfile->napi_mutex);
-			WARN_ON(1);
-			return -ENOMEM;
+			return err;
 		}
 
-		local_bh_disable();
-		napi_gro_frags(&tfile->napi);
-		local_bh_enable();
+		if (likely(napi_schedule_prep(&tfile->napi))) {
+			local_bh_disable();
+			napi_gro_frags(&tfile->napi);
+			napi_complete(&tfile->napi);
+			local_bh_enable();
+		} else {
+			err = -EBUSY;
+			goto napi_busy;
+		}
 		mutex_unlock(&tfile->napi_mutex);
 	} else if (tfile->napi_enabled) {
 		struct sk_buff_head *queue = &tfile->sk.sk_write_queue;
@@ -1911,7 +2003,7 @@ drop:
 	} else if (!IS_ENABLED(CONFIG_4KSTACKS)) {
 		tun_rx_batched(tun, tfile, skb, more);
 	} else {
-		netif_rx_ni(skb);
+		netif_rx(skb);
 	}
 	rcu_read_unlock();
 
@@ -2206,11 +2298,6 @@ static void tun_free_netdev(struct net_device *dev)
 	BUG_ON(!(list_empty(&tun->disabled)));
 
 	free_percpu(dev->tstats);
-	/* We clear tstats so that tun_set_iff() can tell if
-	 * tun_free_netdev() has been called from register_netdevice().
-	 */
-	dev->tstats = NULL;
-
 	tun_flow_uninit(tun);
 	security_tun_dev_free_security(tun->security);
 	__tun_set_ebpf(tun, &tun->steering_prog, NULL);
@@ -2342,9 +2429,10 @@ static int tun_xdp_one(struct tun_struct *tun,
 	struct virtio_net_hdr *gso = &hdr->gso;
 	struct bpf_prog *xdp_prog;
 	struct sk_buff *skb = NULL;
+	struct sk_buff_head *queue;
 	u32 rxhash = 0, act;
 	int buflen = hdr->buflen;
-	int err = 0;
+	int ret = 0;
 	bool skb_xdp = false;
 	struct page *page;
 
@@ -2359,13 +2447,13 @@ static int tun_xdp_one(struct tun_struct *tun,
 		xdp_set_data_meta_invalid(xdp);
 
 		act = bpf_prog_run_xdp(xdp_prog, xdp);
-		err = tun_xdp_act(tun, xdp_prog, xdp, act);
-		if (err < 0) {
+		ret = tun_xdp_act(tun, xdp_prog, xdp, act);
+		if (ret < 0) {
 			put_page(virt_to_head_page(xdp->data));
-			return err;
+			return ret;
 		}
 
-		switch (err) {
+		switch (ret) {
 		case XDP_REDIRECT:
 			*flush = true;
 			fallthrough;
@@ -2389,7 +2477,7 @@ static int tun_xdp_one(struct tun_struct *tun,
 build:
 	skb = build_skb(xdp->data_hard_start, buflen);
 	if (!skb) {
-		err = -ENOMEM;
+		ret = -ENOMEM;
 		goto out;
 	}
 
@@ -2399,7 +2487,7 @@ build:
 	if (virtio_net_hdr_to_skb(skb, gso, tun_is_little_endian(tun))) {
 		atomic_long_inc(&tun->rx_frame_errors);
 		kfree_skb(skb);
-		err = -EINVAL;
+		ret = -EINVAL;
 		goto out;
 	}
 
@@ -2409,16 +2497,27 @@ build:
 	skb_record_rx_queue(skb, tfile->queue_index);
 
 	if (skb_xdp) {
-		err = do_xdp_generic(xdp_prog, skb);
-		if (err != XDP_PASS)
+		ret = do_xdp_generic(xdp_prog, skb);
+		if (ret != XDP_PASS) {
+			ret = 0;
 			goto out;
+		}
 	}
 
 	if (!rcu_dereference(tun->steering_prog) && tun->numqueues > 1 &&
 	    !tfile->detached)
 		rxhash = __skb_get_hash_symmetric(skb);
 
-	netif_receive_skb(skb);
+	if (tfile->napi_enabled) {
+		queue = &tfile->sk.sk_write_queue;
+		spin_lock(&queue->lock);
+		__skb_queue_tail(queue, skb);
+		spin_unlock(&queue->lock);
+		ret = 1;
+	} else {
+		netif_receive_skb(skb);
+		ret = 0;
+	}
 
 	/* No need to disable preemption here since this function is
 	 * always called with bh disabled
@@ -2429,7 +2528,7 @@ build:
 		tun_flow_update(tun, rxhash, tfile);
 
 out:
-	return err;
+	return ret;
 }
 
 static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
@@ -2443,10 +2542,11 @@ static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
 	if (!tun)
 		return -EBADFD;
 
-	if (ctl && (ctl->type == TUN_MSG_PTR)) {
+	if (m->msg_controllen == sizeof(struct tun_msg_ctl) &&
+	    ctl && ctl->type == TUN_MSG_PTR) {
 		struct tun_page tpage;
 		int n = ctl->num;
-		int flush = 0;
+		int flush = 0, queued = 0;
 
 		memset(&tpage, 0, sizeof(tpage));
 
@@ -2455,12 +2555,17 @@ static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
 
 		for (i = 0; i < n; i++) {
 			xdp = &((struct xdp_buff *)ctl->ptr)[i];
-			tun_xdp_one(tun, tfile, xdp, &flush, &tpage);
+			ret = tun_xdp_one(tun, tfile, xdp, &flush, &tpage);
+			if (ret > 0)
+				queued += ret;
 		}
 
 		if (flush)
 			xdp_do_flush();
 
+		if (tfile->napi_enabled && queued > 0)
+			napi_schedule(&tfile->napi);
+
 		rcu_read_unlock();
 		local_bh_enable();
 
@@ -2568,7 +2673,7 @@ static ssize_t tun_flags_show(struct device *dev, struct device_attribute *attr,
 			      char *buf)
 {
 	struct tun_struct *tun = netdev_priv(to_net_dev(dev));
-	return sprintf(buf, "0x%x\n", tun_flags(tun));
+	return sysfs_emit(buf, "0x%x\n", tun_flags(tun));
 }
 
 static ssize_t owner_show(struct device *dev, struct device_attribute *attr,
@@ -2576,9 +2681,9 @@ static ssize_t owner_show(struct device *dev, struct device_attribute *attr,
 {
 	struct tun_struct *tun = netdev_priv(to_net_dev(dev));
 	return uid_valid(tun->owner)?
-		sprintf(buf, "%u\n",
-			from_kuid_munged(current_user_ns(), tun->owner)):
-		sprintf(buf, "-1\n");
+		sysfs_emit(buf, "%u\n",
+			   from_kuid_munged(current_user_ns(), tun->owner)) :
+		sysfs_emit(buf, "-1\n");
 }
 
 static ssize_t group_show(struct device *dev, struct device_attribute *attr,
@@ -2586,9 +2691,9 @@ static ssize_t group_show(struct device *dev, struct device_attribute *attr,
 {
 	struct tun_struct *tun = netdev_priv(to_net_dev(dev));
 	return gid_valid(tun->group) ?
-		sprintf(buf, "%u\n",
-			from_kgid_munged(current_user_ns(), tun->group)):
-		sprintf(buf, "-1\n");
+		sysfs_emit(buf, "%u\n",
+			   from_kgid_munged(current_user_ns(), tun->group)) :
+		sysfs_emit(buf, "-1\n");
 }
 
 static DEVICE_ATTR_RO(tun_flags);
@@ -2716,48 +2821,26 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
 		tun->rx_batched = 0;
 		RCU_INIT_POINTER(tun->steering_prog, NULL);
 
-		dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
-		if (!dev->tstats) {
-			err = -ENOMEM;
-			goto err_free_dev;
-		}
+		tun->ifr = ifr;
+		tun->file = file;
 
-		spin_lock_init(&tun->lock);
-
-		err = security_tun_dev_alloc_security(&tun->security);
-		if (err < 0)
-			goto err_free_stat;
-
-		tun_net_init(dev);
-		tun_flow_init(tun);
-
-		dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
-				   TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
-				   NETIF_F_HW_VLAN_STAG_TX;
-		dev->features = dev->hw_features | NETIF_F_LLTX;
-		dev->vlan_features = dev->features &
-				     ~(NETIF_F_HW_VLAN_CTAG_TX |
-				       NETIF_F_HW_VLAN_STAG_TX);
-
-		tun->flags = (tun->flags & ~TUN_FEATURES) |
-			      (ifr->ifr_flags & TUN_FEATURES);
-
-		INIT_LIST_HEAD(&tun->disabled);
-		err = tun_attach(tun, file, false, ifr->ifr_flags & IFF_NAPI,
-				 ifr->ifr_flags & IFF_NAPI_FRAGS, false);
-		if (err < 0)
-			goto err_free_flow;
+		tun_net_initialize(dev);
 
 		err = register_netdevice(tun->dev);
-		if (err < 0)
-			goto err_detach;
+		if (err < 0) {
+			free_netdev(dev);
+			return err;
+		}
 		/* free_netdev() won't check refcnt, to avoid race
 		 * with dev_put() we need publish tun after registration.
 		 */
 		rcu_assign_pointer(tfile->tun, tun);
 	}
 
-	netif_carrier_on(tun->dev);
+	if (ifr->ifr_flags & IFF_NO_CARRIER)
+		netif_carrier_off(tun->dev);
+	else
+		netif_carrier_on(tun->dev);
 
 	/* Make sure persistent devices do not get stuck in
 	 * xoff state.
@@ -2767,24 +2850,6 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
 
 	strcpy(ifr->ifr_name, tun->dev->name);
 	return 0;
-
-err_detach:
-	tun_detach_all(dev);
-	/* We are here because register_netdevice() has failed.
-	 * If register_netdevice() already called tun_free_netdev()
-	 * while dealing with the error, dev->stats has been cleared.
-	 */
-	if (!dev->tstats)
-		goto err_free_dev;
-
-err_free_flow:
-	tun_flow_uninit(tun);
-	security_tun_dev_free_security(tun->security);
-err_free_stat:
-	free_percpu(dev->tstats);
-err_free_dev:
-	free_netdev(dev);
-	return err;
 }
 
 static void tun_get_iff(struct tun_struct *tun, struct ifreq *ifr)
@@ -3003,8 +3068,8 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
 		 * This is needed because we never checked for invalid flags on
 		 * TUNSETIFF.
 		 */
-		return put_user(IFF_TUN | IFF_TAP | TUN_FEATURES,
-				(unsigned int __user*)argp);
+		return put_user(IFF_TUN | IFF_TAP | IFF_NO_CARRIER |
+				TUN_FEATURES, (unsigned int __user*)argp);
 	} else if (cmd == TUNSETQUEUE) {
 		return tun_set_queue(file, &ifr);
 	} else if (cmd == SIOCGSKNS) {
@@ -3487,15 +3552,15 @@ static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info
 {
 	struct tun_struct *tun = netdev_priv(dev);
 
-	strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
-	strlcpy(info->version, DRV_VERSION, sizeof(info->version));
+	strscpy(info->driver, DRV_NAME, sizeof(info->driver));
+	strscpy(info->version, DRV_VERSION, sizeof(info->version));
 
 	switch (tun->flags & TUN_TYPE_MASK) {
 	case IFF_TUN:
-		strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
+		strscpy(info->bus_info, "tun", sizeof(info->bus_info));
 		break;
 	case IFF_TAP:
-		strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
+		strscpy(info->bus_info, "tap", sizeof(info->bus_info));
 		break;
 	}
 }