Revert "net: Move {l,t,d}stats allocation to core and convert veth & vrf"

This reverts commit 877c81faf0 which is
commit 34d21de99cea9cb17967874313e5b0262527833c upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: I9a8aac914cc10fb293d8ff1fcaedf88122f907a8
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/net/veth.c

@@ -1381,12 +1381,25 @@ static void veth_free_queues(struct net_device *dev)
 
 static int veth_dev_init(struct net_device *dev)
 {
-	return veth_alloc_queues(dev);
+	int err;
+
+	dev->lstats = netdev_alloc_pcpu_stats(struct pcpu_lstats);
+	if (!dev->lstats)
+		return -ENOMEM;
+
+	err = veth_alloc_queues(dev);
+	if (err) {
+		free_percpu(dev->lstats);
+		return err;
+	}
+
+	return 0;
 }
 
 static void veth_dev_free(struct net_device *dev)
 {
 	veth_free_queues(dev);
+	free_percpu(dev->lstats);
 }
 
 #ifdef CONFIG_NET_POLL_CONTROLLER
@@ -1612,7 +1625,6 @@ static void veth_setup(struct net_device *dev)
 			       NETIF_F_HW_VLAN_STAG_RX);
 	dev->needs_free_netdev = true;
 	dev->priv_destructor = veth_dev_free;
-	dev->pcpu_stat_type = NETDEV_PCPU_STAT_LSTATS;
 	dev->max_mtu = ETH_MAX_MTU;
 
 	dev->hw_features = VETH_FEATURES;

drivers/net/vrf.c

@@ -121,12 +121,22 @@ struct net_vrf {
 	int			ifindex;
 };
 
+struct pcpu_dstats {
+	u64			tx_pkts;
+	u64			tx_bytes;
+	u64			tx_drps;
+	u64			rx_pkts;
+	u64			rx_bytes;
+	u64			rx_drps;
+	struct u64_stats_sync	syncp;
+};
+
 static void vrf_rx_stats(struct net_device *dev, int len)
 {
 	struct pcpu_dstats *dstats = this_cpu_ptr(dev->dstats);
 
 	u64_stats_update_begin(&dstats->syncp);
-	dstats->rx_packets++;
+	dstats->rx_pkts++;
 	dstats->rx_bytes += len;
 	u64_stats_update_end(&dstats->syncp);
 }
@@ -151,10 +161,10 @@ static void vrf_get_stats64(struct net_device *dev,
 		do {
 			start = u64_stats_fetch_begin_irq(&dstats->syncp);
 			tbytes = dstats->tx_bytes;
-			tpkts = dstats->tx_packets;
+			tpkts = dstats->tx_pkts;
-			tdrops = dstats->tx_drops;
+			tdrops = dstats->tx_drps;
 			rbytes = dstats->rx_bytes;
-			rpkts = dstats->rx_packets;
+			rpkts = dstats->rx_pkts;
 		} while (u64_stats_fetch_retry_irq(&dstats->syncp, start));
 		stats->tx_bytes += tbytes;
 		stats->tx_packets += tpkts;
@@ -411,7 +421,7 @@ static int vrf_local_xmit(struct sk_buff *skb, struct net_device *dev,
 	if (likely(__netif_rx(skb) == NET_RX_SUCCESS))
 		vrf_rx_stats(dev, len);
 	else
-		this_cpu_inc(dev->dstats->rx_drops);
+		this_cpu_inc(dev->dstats->rx_drps);
 
 	return NETDEV_TX_OK;
 }
@@ -606,11 +616,11 @@ static netdev_tx_t vrf_xmit(struct sk_buff *skb, struct net_device *dev)
 		struct pcpu_dstats *dstats = this_cpu_ptr(dev->dstats);
 
 		u64_stats_update_begin(&dstats->syncp);
-		dstats->tx_packets++;
+		dstats->tx_pkts++;
 		dstats->tx_bytes += len;
 		u64_stats_update_end(&dstats->syncp);
 	} else {
-		this_cpu_inc(dev->dstats->tx_drops);
+		this_cpu_inc(dev->dstats->tx_drps);
 	}
 
 	return ret;

include/linux/netdevice.h

@@ -1780,13 +1780,6 @@ enum netdev_ml_priv_type {
 	ML_PRIV_CAN,
 };
 
-enum netdev_stat_type {
-	NETDEV_PCPU_STAT_NONE,
-	NETDEV_PCPU_STAT_LSTATS, /* struct pcpu_lstats */
-	NETDEV_PCPU_STAT_TSTATS, /* struct pcpu_sw_netstats */
-	NETDEV_PCPU_STAT_DSTATS, /* struct pcpu_dstats */
-};
-
 /**
  *	struct net_device - The DEVICE structure.
  *
@@ -1981,14 +1974,10 @@ enum netdev_stat_type {
  *
  * 	@ml_priv:	Mid-layer private
  *	@ml_priv_type:  Mid-layer private type
- *
+ * 	@lstats:	Loopback statistics
- *	@pcpu_stat_type:	Type of device statistics which the core should
+ * 	@tstats:	Tunnel statistics
- *				allocate/free: none, lstats, tstats, dstats. none
+ * 	@dstats:	Dummy statistics
- *				means the driver is handling statistics allocation/
+ * 	@vstats:	Virtual ethernet statistics
- *				freeing internally.
- *	@lstats:		Loopback statistics: packets, bytes
- *	@tstats:		Tunnel statistics: RX/TX packets, RX/TX bytes
- *	@dstats:		Dummy statistics: RX/TX/drop packets, RX/TX bytes
  *
  *	@garp_port:	GARP
  *	@mrp_port:	MRP
@@ -2339,7 +2328,6 @@ struct net_device {
 	void				*ml_priv;
 	enum netdev_ml_priv_type	ml_priv_type;
 
-	enum netdev_stat_type		pcpu_stat_type:8;
 	union {
 		struct pcpu_lstats __percpu		*lstats;
 		struct pcpu_sw_netstats __percpu	*tstats;
@@ -2737,16 +2725,6 @@ struct pcpu_sw_netstats {
 	struct u64_stats_sync   syncp;
 } __aligned(4 * sizeof(u64));
 
-struct pcpu_dstats {
-	u64			rx_packets;
-	u64			rx_bytes;
-	u64			rx_drops;
-	u64			tx_packets;
-	u64			tx_bytes;
-	u64			tx_drops;
-	struct u64_stats_sync	syncp;
-} __aligned(8 * sizeof(u64));
-
 struct pcpu_lstats {
 	u64_stats_t packets;
 	u64_stats_t bytes;

net/core/dev.c

@@ -10007,46 +10007,6 @@ void netif_tx_stop_all_queues(struct net_device *dev)
 }
 EXPORT_SYMBOL(netif_tx_stop_all_queues);
 
-static int netdev_do_alloc_pcpu_stats(struct net_device *dev)
-{
-	void __percpu *v;
-
-	switch (dev->pcpu_stat_type) {
-	case NETDEV_PCPU_STAT_NONE:
-		return 0;
-	case NETDEV_PCPU_STAT_LSTATS:
-		v = dev->lstats = netdev_alloc_pcpu_stats(struct pcpu_lstats);
-		break;
-	case NETDEV_PCPU_STAT_TSTATS:
-		v = dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
-		break;
-	case NETDEV_PCPU_STAT_DSTATS:
-		v = dev->dstats = netdev_alloc_pcpu_stats(struct pcpu_dstats);
-		break;
-	default:
-		return -EINVAL;
-	}
-
-	return v ? 0 : -ENOMEM;
-}
-
-static void netdev_do_free_pcpu_stats(struct net_device *dev)
-{
-	switch (dev->pcpu_stat_type) {
-	case NETDEV_PCPU_STAT_NONE:
-		return;
-	case NETDEV_PCPU_STAT_LSTATS:
-		free_percpu(dev->lstats);
-		break;
-	case NETDEV_PCPU_STAT_TSTATS:
-		free_percpu(dev->tstats);
-		break;
-	case NETDEV_PCPU_STAT_DSTATS:
-		free_percpu(dev->dstats);
-		break;
-	}
-}
-
 /**
  * register_netdevice() - register a network device
  * @dev: device to register
@@ -10107,15 +10067,11 @@ int register_netdevice(struct net_device *dev)
 		goto err_uninit;
 	}
 
-	ret = netdev_do_alloc_pcpu_stats(dev);
-	if (ret)
-		goto err_uninit;
-
 	ret = -EBUSY;
 	if (!dev->ifindex)
 		dev->ifindex = dev_new_index(net);
 	else if (__dev_get_by_index(net, dev->ifindex))
-		goto err_free_pcpu;
+		goto err_uninit;
 
 	/* Transfer changeable features to wanted_features and enable
 	 * software offloads (GSO and GRO).
@@ -10162,14 +10118,14 @@ int register_netdevice(struct net_device *dev)
 	ret = call_netdevice_notifiers(NETDEV_POST_INIT, dev);
 	ret = notifier_to_errno(ret);
 	if (ret)
-		goto err_free_pcpu;
+		goto err_uninit;
 
 	ret = netdev_register_kobject(dev);
 	write_lock(&dev_base_lock);
 	dev->reg_state = ret ? NETREG_UNREGISTERED : NETREG_REGISTERED;
 	write_unlock(&dev_base_lock);
 	if (ret)
-		goto err_free_pcpu;
+		goto err_uninit;
 
 	__netdev_update_features(dev);
 
@@ -10216,8 +10172,6 @@ int register_netdevice(struct net_device *dev)
 out:
 	return ret;
 
-err_free_pcpu:
-	netdev_do_free_pcpu_stats(dev);
 err_uninit:
 	if (dev->netdev_ops->ndo_uninit)
 		dev->netdev_ops->ndo_uninit(dev);
@@ -10471,7 +10425,6 @@ void netdev_run_todo(void)
 		WARN_ON(rcu_access_pointer(dev->ip_ptr));
 		WARN_ON(rcu_access_pointer(dev->ip6_ptr));
 
-		netdev_do_free_pcpu_stats(dev);
 		if (dev->priv_destructor)
 			dev->priv_destructor(dev);
 		if (dev->needs_free_netdev)