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>

18 files changed, 89 insertions, 71 deletions

diff --git a/arch/s390/appldata/appldata_net_sum.c b/arch/s390/appldata/appldata_net_sum.c
index 9a9586f4103f..f02e89ce4df1 100644
--- a/arch/s390/appldata/appldata_net_sum.c
+++ b/arch/s390/appldata/appldata_net_sum.c
@@ -85,7 +85,8 @@ static void appldata_get_net_sum_data(void *data)
 
         rcu_read_lock();
         for_each_netdev_rcu(&init_net, dev) {
-                const struct net_device_stats *stats = dev_get_stats(dev);
+                struct rtnl_link_stats64 temp;
+                const struct net_device_stats *stats = dev_get_stats(dev, &temp);
 
                 rx_packets += stats->rx_packets;
                 tx_packets += stats->tx_packets;
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index a95a41b74b4e..9bb9bfa225b6 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 b35ef36741ef..da54b38bb480 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 4dd0510d7a99..9a0996795321 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 e6d626e78515..6112f1498940 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 35b3f2922e5c..ba674c5ca29e 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 3b8b0a062749..fd19d6ab97a2 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 188bc8496a26..18dff43b8bd2 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 44a07593de56..1a429ed6da9d 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 5ede9c255094..96c86c873011 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 fb69b01c8f3a..020fa5a25fda 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) {
 
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 4d27368674db..60de65316fdb 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -666,7 +666,8 @@ struct netdev_rx_queue {
  *      Callback uses when the transmitter has not made any progress
  *      for dev->watchdog ticks.
  *
- * struct rtnl_link_stats64* (*ndo_get_stats64)(struct net_device *dev);
+ * struct rtnl_link_stats64* (*ndo_get_stats64)(struct net_device *dev
+ *                      struct rtnl_link_stats64 *storage);
  * struct net_device_stats* (*ndo_get_stats)(struct net_device *dev);
  *      Called when a user wants to get the network device usage
  *      statistics. Drivers must do one of the following:
@@ -733,7 +734,8 @@ struct net_device_ops {
                                                    struct neigh_parms *);
         void                    (*ndo_tx_timeout) (struct net_device *dev);
 
-        struct rtnl_link_stats64* (*ndo_get_stats64)(struct net_device *dev);
+        struct rtnl_link_stats64* (*ndo_get_stats64)(struct net_device *dev,
+                                                     struct rtnl_link_stats64 *storage);
         struct net_device_stats* (*ndo_get_stats)(struct net_device *dev);
 
         void                    (*ndo_vlan_rx_register)(struct net_device *dev,
@@ -2139,8 +2141,10 @@ extern void		netdev_features_change(struct net_device *dev);
 /* Load a device via the kmod */
 extern void             dev_load(struct net *net, const char *name);
 extern void             dev_mcast_init(void);
-extern const struct rtnl_link_stats64 *dev_get_stats(struct net_device *dev);
-extern void             dev_txq_stats_fold(const struct net_device *dev, struct net_device_stats *stats);
+extern const struct rtnl_link_stats64 *dev_get_stats(struct net_device *dev,
+                                                     struct rtnl_link_stats64 *storage);
+extern void             dev_txq_stats_fold(const struct net_device *dev,
+                                           struct net_device_stats *stats);
 
 extern int              netdev_max_backlog;
 extern int              netdev_tstamp_prequeue;
diff --git a/net/8021q/vlan_dev.c b/net/8021q/vlan_dev.c
index c6456cb842fa..7865a4ce5250 100644
--- a/net/8021q/vlan_dev.c
+++ b/net/8021q/vlan_dev.c
@@ -803,11 +803,9 @@ static u32 vlan_ethtool_get_flags(struct net_device *dev)
         return dev_ethtool_get_flags(vlan->real_dev);
 }
 
-static struct rtnl_link_stats64 *vlan_dev_get_stats64(struct net_device *dev)
+static struct rtnl_link_stats64 *vlan_dev_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
 {
-        struct rtnl_link_stats64 *stats = &dev->stats64;
-
-        dev_txq_stats_fold(dev, &dev->stats);
+        dev_txq_stats_fold(dev, (struct net_device_stats *)stats);
 
         if (vlan_dev_info(dev)->vlan_rx_stats) {
                 struct vlan_rx_stats *p, accum = {0};
diff --git a/net/8021q/vlanproc.c b/net/8021q/vlanproc.c
index df56f5ce887c..80e280f56686 100644
--- a/net/8021q/vlanproc.c
+++ b/net/8021q/vlanproc.c
@@ -278,6 +278,7 @@ static int vlandev_seq_show(struct seq_file *seq, void *offset)
 {
         struct net_device *vlandev = (struct net_device *) seq->private;
         const struct vlan_dev_info *dev_info = vlan_dev_info(vlandev);
+        struct rtnl_link_stats64 temp;
         const struct rtnl_link_stats64 *stats;
         static const char fmt[] = "%30s %12lu\n";
         static const char fmt64[] = "%30s %12llu\n";
@@ -286,7 +287,7 @@ static int vlandev_seq_show(struct seq_file *seq, void *offset)
         if (!is_vlan_dev(vlandev))
                 return 0;
 
-        stats = dev_get_stats(vlandev);
+        stats = dev_get_stats(vlandev, &temp);
         seq_printf(seq,
                    "%s  VID: %d  REORDER_HDR: %i  dev->priv_flags: %hx\n",
                    vlandev->name, dev_info->vlan_id,
diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c
index edf639e96281..075c435ad22d 100644
--- a/net/bridge/br_device.c
+++ b/net/bridge/br_device.c
@@ -98,10 +98,10 @@ static int br_dev_stop(struct net_device *dev)
         return 0;
 }
 
-static struct rtnl_link_stats64 *br_get_stats64(struct net_device *dev)
+static struct rtnl_link_stats64 *br_get_stats64(struct net_device *dev,
+                                                struct rtnl_link_stats64 *stats)
 {
         struct net_bridge *br = netdev_priv(dev);
-        struct rtnl_link_stats64 *stats = &dev->stats64;
         struct br_cpu_netstats tmp, sum = { 0 };
         unsigned int cpu;
 
diff --git a/net/core/dev.c b/net/core/dev.c
index 93b8929fa21d..92482d7a87a9 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3703,7 +3703,8 @@ void dev_seq_stop(struct seq_file *seq, void *v)
 
 static void dev_seq_printf_stats(struct seq_file *seq, struct net_device *dev)
 {
-        const struct rtnl_link_stats64 *stats = dev_get_stats(dev);
+        struct rtnl_link_stats64 temp;
+        const struct rtnl_link_stats64 *stats = dev_get_stats(dev, &temp);
 
         seq_printf(seq, "%6s: %7llu %7llu %4llu %4llu %4llu %5llu %10llu %9llu "
                    "%8llu %7llu %4llu %4llu %4llu %5llu %7llu %10llu\n",
@@ -5281,23 +5282,29 @@ EXPORT_SYMBOL(dev_txq_stats_fold);
 /**
  *      dev_get_stats   - get network device statistics
  *      @dev: device to get statistics from
+ *      @storage: place to store stats
  *
  *      Get network statistics from device. The device driver may provide
  *      its own method by setting dev->netdev_ops->get_stats64 or
  *      dev->netdev_ops->get_stats; otherwise the internal statistics
  *      structure is used.
  */
-const struct rtnl_link_stats64 *dev_get_stats(struct net_device *dev)
+const struct rtnl_link_stats64 *dev_get_stats(struct net_device *dev,
+                                              struct rtnl_link_stats64 *storage)
 {
         const struct net_device_ops *ops = dev->netdev_ops;
 
-        if (ops->ndo_get_stats64)
-                return ops->ndo_get_stats64(dev);
-        if (ops->ndo_get_stats)
-                return (struct rtnl_link_stats64 *)ops->ndo_get_stats(dev);
-
-        dev_txq_stats_fold(dev, &dev->stats);
-        return &dev->stats64;
+        if (ops->ndo_get_stats64) {
+                memset(storage, 0, sizeof(*storage));
+                return ops->ndo_get_stats64(dev, storage);
+        }
+        if (ops->ndo_get_stats) {
+                memcpy(storage, ops->ndo_get_stats(dev), sizeof(*storage));
+                return storage;
+        }
+        memcpy(storage, &dev->stats, sizeof(*storage));
+        dev_txq_stats_fold(dev, (struct net_device_stats *)storage);
+        return storage;
 }
 EXPORT_SYMBOL(dev_get_stats);
 
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index ea3bb4c3b87d..914f42b0f039 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -330,7 +330,9 @@ static ssize_t netstat_show(const struct device *d,
 
         read_lock(&dev_base_lock);
         if (dev_isalive(dev)) {
-                const struct rtnl_link_stats64 *stats = dev_get_stats(dev);
+                struct rtnl_link_stats64 temp;
+                const struct rtnl_link_stats64 *stats = dev_get_stats(dev, &temp);
+
                 ret = sprintf(buf, fmt_u64, *(u64 *)(((u8 *) stats) + offset));
         }
         read_unlock(&dev_base_lock);
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index e645778e9b7e..5e773ea2201d 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -791,6 +791,7 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
 {
         struct ifinfomsg *ifm;
         struct nlmsghdr *nlh;
+        struct rtnl_link_stats64 temp;
         const struct rtnl_link_stats64 *stats;
         struct nlattr *attr;
 
@@ -847,7 +848,7 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
         if (attr == NULL)
                 goto nla_put_failure;
 
-        stats = dev_get_stats(dev);
+        stats = dev_get_stats(dev, &temp);
         copy_rtnl_link_stats(nla_data(attr), stats);
 
         attr = nla_reserve(skb, IFLA_STATS64,