net: fix 64 bit counters on 32 bit arches

There is a small possibility that a reader gets incorrect values on 32
bit arches. SNMP applications could catch incorrect counters when a
32bit high part is changed by another stats consumer/provider.

One way to solve this is to add a rtnl_link_stats64 param to all
ndo_get_stats64() methods, and also add such a parameter to
dev_get_stats().

Rule is that we are not allowed to use dev->stats64 as a temporary
storage for 64bit stats, but a caller provided area (usually on stack)

Old drivers (only providing get_stats() method) need no changes.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

10 files changed, 52 insertions, 48 deletions

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index a95a41b..9bb9bfa 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -3804,51 +3804,49 @@ static int bond_close(struct net_device *bond_dev)
 	return 0;
 }
 
-static struct rtnl_link_stats64 *bond_get_stats(struct net_device *bond_dev)
+static struct rtnl_link_stats64 *bond_get_stats(struct net_device *bond_dev,
+						struct rtnl_link_stats64 *stats)
 {
 	struct bonding *bond = netdev_priv(bond_dev);
-	struct rtnl_link_stats64 *stats = &bond_dev->stats64;
-	struct rtnl_link_stats64 local_stats;
+	struct rtnl_link_stats64 temp;
 	struct slave *slave;
 	int i;
 
-	memset(&local_stats, 0, sizeof(local_stats));
+	memset(stats, 0, sizeof(*stats));
 
 	read_lock_bh(&bond->lock);
 
 	bond_for_each_slave(bond, slave, i) {
 		const struct rtnl_link_stats64 *sstats =
-			dev_get_stats(slave->dev);
-
-		local_stats.rx_packets += sstats->rx_packets;
-		local_stats.rx_bytes += sstats->rx_bytes;
-		local_stats.rx_errors += sstats->rx_errors;
-		local_stats.rx_dropped += sstats->rx_dropped;
-
-		local_stats.tx_packets += sstats->tx_packets;
-		local_stats.tx_bytes += sstats->tx_bytes;
-		local_stats.tx_errors += sstats->tx_errors;
-		local_stats.tx_dropped += sstats->tx_dropped;
-
-		local_stats.multicast += sstats->multicast;
-		local_stats.collisions += sstats->collisions;
-
-		local_stats.rx_length_errors += sstats->rx_length_errors;
-		local_stats.rx_over_errors += sstats->rx_over_errors;
-		local_stats.rx_crc_errors += sstats->rx_crc_errors;
-		local_stats.rx_frame_errors += sstats->rx_frame_errors;
-		local_stats.rx_fifo_errors += sstats->rx_fifo_errors;
-		local_stats.rx_missed_errors += sstats->rx_missed_errors;
-
-		local_stats.tx_aborted_errors += sstats->tx_aborted_errors;
-		local_stats.tx_carrier_errors += sstats->tx_carrier_errors;
-		local_stats.tx_fifo_errors += sstats->tx_fifo_errors;
-		local_stats.tx_heartbeat_errors += sstats->tx_heartbeat_errors;
-		local_stats.tx_window_errors += sstats->tx_window_errors;
+			dev_get_stats(slave->dev, &temp);
+
+		stats->rx_packets += sstats->rx_packets;
+		stats->rx_bytes += sstats->rx_bytes;
+		stats->rx_errors += sstats->rx_errors;
+		stats->rx_dropped += sstats->rx_dropped;
+
+		stats->tx_packets += sstats->tx_packets;
+		stats->tx_bytes += sstats->tx_bytes;
+		stats->tx_errors += sstats->tx_errors;
+		stats->tx_dropped += sstats->tx_dropped;
+
+		stats->multicast += sstats->multicast;
+		stats->collisions += sstats->collisions;
+
+		stats->rx_length_errors += sstats->rx_length_errors;
+		stats->rx_over_errors += sstats->rx_over_errors;
+		stats->rx_crc_errors += sstats->rx_crc_errors;
+		stats->rx_frame_errors += sstats->rx_frame_errors;
+		stats->rx_fifo_errors += sstats->rx_fifo_errors;
+		stats->rx_missed_errors += sstats->rx_missed_errors;
+
+		stats->tx_aborted_errors += sstats->tx_aborted_errors;
+		stats->tx_carrier_errors += sstats->tx_carrier_errors;
+		stats->tx_fifo_errors += sstats->tx_fifo_errors;
+		stats->tx_heartbeat_errors += sstats->tx_heartbeat_errors;
+		stats->tx_window_errors += sstats->tx_window_errors;
 	}
 
-	memcpy(stats, &local_stats, sizeof(struct net_device_stats));
-
 	read_unlock_bh(&bond->lock);
 
 	return stats;
diff --git a/drivers/net/ixgbe/ixgbe_ethtool.c b/drivers/net/ixgbe/ixgbe_ethtool.c
index b35ef36..da54b38 100644
--- a/drivers/net/ixgbe/ixgbe_ethtool.c
+++ b/drivers/net/ixgbe/ixgbe_ethtool.c
@@ -55,7 +55,7 @@ struct ixgbe_stats {
 				offsetof(struct ixgbe_adapter, m)
 #define IXGBE_NETDEV_STAT(m)	NETDEV_STATS, \
 				sizeof(((struct net_device *)0)->m), \
-				offsetof(struct net_device, m)
+				offsetof(struct net_device, m) - offsetof(struct net_device, stats)
 
 static struct ixgbe_stats ixgbe_gstrings_stats[] = {
 	{"rx_packets", IXGBE_NETDEV_STAT(stats.rx_packets)},
@@ -998,16 +998,18 @@ static void ixgbe_get_ethtool_stats(struct net_device *netdev,
 	struct ixgbe_adapter *adapter = netdev_priv(netdev);
 	u64 *queue_stat;
 	int stat_count = sizeof(struct ixgbe_queue_stats) / sizeof(u64);
+	struct rtnl_link_stats64 temp;
+	const struct rtnl_link_stats64 *net_stats;
 	int j, k;
 	int i;
 	char *p = NULL;
 
 	ixgbe_update_stats(adapter);
-	dev_get_stats(netdev);
+	net_stats = dev_get_stats(netdev, &temp);
 	for (i = 0; i < IXGBE_GLOBAL_STATS_LEN; i++) {
 		switch (ixgbe_gstrings_stats[i].type) {
 		case NETDEV_STATS:
-			p = (char *) netdev +
+			p = (char *) net_stats +
 					ixgbe_gstrings_stats[i].stat_offset;
 			break;
 		case IXGBE_STATS:
diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c
index 4dd0510..9a09967 100644
--- a/drivers/net/loopback.c
+++ b/drivers/net/loopback.c
@@ -98,10 +98,10 @@ static netdev_tx_t loopback_xmit(struct sk_buff *skb,
 	return NETDEV_TX_OK;
 }
 
-static struct rtnl_link_stats64 *loopback_get_stats64(struct net_device *dev)
+static struct rtnl_link_stats64 *loopback_get_stats64(struct net_device *dev,
+						      struct rtnl_link_stats64 *stats)
 {
 	const struct pcpu_lstats __percpu *pcpu_lstats;
-	struct rtnl_link_stats64 *stats = &dev->stats64;
 	u64 bytes = 0;
 	u64 packets = 0;
 	u64 drops = 0;
diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index e6d626e..6112f14 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -431,12 +431,12 @@ static void macvlan_uninit(struct net_device *dev)
 	free_percpu(vlan->rx_stats);
 }
 
-static struct rtnl_link_stats64 *macvlan_dev_get_stats64(struct net_device *dev)
+static struct rtnl_link_stats64 *macvlan_dev_get_stats64(struct net_device *dev,
+							 struct rtnl_link_stats64 *stats)
 {
-	struct rtnl_link_stats64 *stats = &dev->stats64;
 	struct macvlan_dev *vlan = netdev_priv(dev);
 
-	dev_txq_stats_fold(dev, &dev->stats);
+	dev_txq_stats_fold(dev, (struct net_device_stats *)stats);
 
 	if (vlan->rx_stats) {
 		struct macvlan_rx_stats *p, accum = {0};
diff --git a/drivers/net/sfc/efx.c b/drivers/net/sfc/efx.c
index 35b3f29..ba674c5 100644
--- a/drivers/net/sfc/efx.c
+++ b/drivers/net/sfc/efx.c
@@ -1533,11 +1533,10 @@ static int efx_net_stop(struct net_device *net_dev)
 }
 
 /* Context: process, dev_base_lock or RTNL held, non-blocking. */
-static struct rtnl_link_stats64 *efx_net_stats(struct net_device *net_dev)
+static struct rtnl_link_stats64 *efx_net_stats(struct net_device *net_dev, struct rtnl_link_stats64 *stats)
 {
 	struct efx_nic *efx = netdev_priv(net_dev);
 	struct efx_mac_stats *mac_stats = &efx->mac_stats;
-	struct rtnl_link_stats64 *stats = &net_dev->stats64;
 
 	spin_lock_bh(&efx->stats_lock);
 	efx->type->update_stats(efx);
diff --git a/drivers/net/sfc/ethtool.c b/drivers/net/sfc/ethtool.c
index 3b8b0a0..fd19d6a 100644
--- a/drivers/net/sfc/ethtool.c
+++ b/drivers/net/sfc/ethtool.c
@@ -469,12 +469,13 @@ static void efx_ethtool_get_stats(struct net_device *net_dev,
 	struct efx_mac_stats *mac_stats = &efx->mac_stats;
 	struct efx_ethtool_stat *stat;
 	struct efx_channel *channel;
+	struct rtnl_link_stats64 temp;
 	int i;
 
 	EFX_BUG_ON_PARANOID(stats->n_stats != EFX_ETHTOOL_NUM_STATS);
 
 	/* Update MAC and NIC statistics */
-	dev_get_stats(net_dev);
+	dev_get_stats(net_dev, &temp);
 
 	/* Fill detailed statistics buffer */
 	for (i = 0; i < EFX_ETHTOOL_NUM_STATS; i++) {
diff --git a/drivers/parisc/led.c b/drivers/parisc/led.c
index 188bc84..18dff43 100644
--- a/drivers/parisc/led.c
+++ b/drivers/parisc/led.c
@@ -355,12 +355,13 @@ static __inline__ int led_get_net_activity(void)
 	rcu_read_lock();
 	for_each_netdev_rcu(&init_net, dev) {
 	    const struct net_device_stats *stats;
+	    struct rtnl_link_stats64 temp;
 	    struct in_device *in_dev = __in_dev_get_rcu(dev);
 	    if (!in_dev || !in_dev->ifa_list)
 		continue;
 	    if (ipv4_is_loopback(in_dev->ifa_list->ifa_local))
 		continue;
-	    stats = dev_get_stats(dev);
+	    stats = dev_get_stats(dev, &temp);
 	    rx_total += stats->rx_packets;
 	    tx_total += stats->tx_packets;
 	}
diff --git a/drivers/scsi/fcoe/fcoe.c b/drivers/scsi/fcoe/fcoe.c
index 44a0759..1a429ed 100644
--- a/drivers/scsi/fcoe/fcoe.c
+++ b/drivers/scsi/fcoe/fcoe.c
@@ -2653,6 +2653,7 @@ static void fcoe_get_lesb(struct fc_lport *lport,
 	u32 lfc, vlfc, mdac;
 	struct fcoe_dev_stats *devst;
 	struct fcoe_fc_els_lesb *lesb;
+	struct rtnl_link_stats64 temp;
 	struct net_device *netdev = fcoe_netdev(lport);
 
 	lfc = 0;
@@ -2669,7 +2670,7 @@ static void fcoe_get_lesb(struct fc_lport *lport,
 	lesb->lesb_link_fail = htonl(lfc);
 	lesb->lesb_vlink_fail = htonl(vlfc);
 	lesb->lesb_miss_fka = htonl(mdac);
-	lesb->lesb_fcs_error = htonl(dev_get_stats(netdev)->rx_crc_errors);
+	lesb->lesb_fcs_error = htonl(dev_get_stats(netdev, &temp)->rx_crc_errors);
 }
 
 /**
diff --git a/drivers/staging/batman-adv/hard-interface.c b/drivers/staging/batman-adv/hard-interface.c
index 5ede9c2..96c86c8 100644
--- a/drivers/staging/batman-adv/hard-interface.c
+++ b/drivers/staging/batman-adv/hard-interface.c
@@ -440,6 +440,7 @@ int batman_skb_recv(struct sk_buff *skb, struct net_device *dev,
 	struct batman_packet *batman_packet;
 	struct batman_if *batman_if;
 	struct net_device_stats *stats;
+	struct rtnl_link_stats64 temp;
 	int ret;
 
 	skb = skb_share_check(skb, GFP_ATOMIC);
@@ -468,7 +469,7 @@ int batman_skb_recv(struct sk_buff *skb, struct net_device *dev,
 	if (batman_if->if_status != IF_ACTIVE)
 		goto err_free;
 
-	stats = (struct net_device_stats *)dev_get_stats(skb->dev);
+	stats = (struct net_device_stats *)dev_get_stats(skb->dev, &temp);
 	if (stats) {
 		stats->rx_packets++;
 		stats->rx_bytes += skb->len;
diff --git a/drivers/usb/gadget/rndis.c b/drivers/usb/gadget/rndis.c
index fb69b01..020fa5a 100644
--- a/drivers/usb/gadget/rndis.c
+++ b/drivers/usb/gadget/rndis.c
@@ -171,6 +171,7 @@ gen_ndis_query_resp (int configNr, u32 OID, u8 *buf, unsigned buf_len,
 	int			i, count;
 	rndis_query_cmplt_type	*resp;
 	struct net_device	*net;
+	struct rtnl_link_stats64 temp;
 	const struct rtnl_link_stats64 *stats;
 
 	if (!r) return -ENOMEM;
@@ -194,7 +195,7 @@ gen_ndis_query_resp (int configNr, u32 OID, u8 *buf, unsigned buf_len,
 	resp->InformationBufferOffset = cpu_to_le32 (16);
 
 	net = rndis_per_dev_params[configNr].dev;
-	stats = dev_get_stats(net);
+	stats = dev_get_stats(net, &temp);
 
 	switch (OID) {