be2net: fix netdev_stats_update

Problem initially reproted and fixed by Eric Dumazet <eric.dumazet@gmail.com>

netdev_stats_update() resets netdev->stats and then accumulates stats from
various rings. This is wrong as stats readers can sometimes catch zero values.
Use temporary variables instead for accumulating per-ring values.

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

1 files changed, 17 insertions, 12 deletions

diff --git a/drivers/net/benet/be_main.c b/drivers/net/benet/be_main.c
index c4f564cd745b..5ca06b0d2d0c 100644
--- a/drivers/net/benet/be_main.c
+++ b/drivers/net/benet/be_main.c
@@ -428,33 +428,38 @@ void netdev_stats_update(struct be_adapter *adapter)
         struct net_device_stats *dev_stats = &adapter->netdev->stats;
         struct be_rx_obj *rxo;
         struct be_tx_obj *txo;
+        unsigned long pkts = 0, bytes = 0, mcast = 0, drops = 0;
         int i;
 
-        memset(dev_stats, 0, sizeof(*dev_stats));
         for_all_rx_queues(adapter, rxo, i) {
-                dev_stats->rx_packets += rx_stats(rxo)->rx_pkts;
-                dev_stats->rx_bytes += rx_stats(rxo)->rx_bytes;
-                dev_stats->multicast += rx_stats(rxo)->rx_mcast_pkts;
+                pkts += rx_stats(rxo)->rx_pkts;
+                bytes += rx_stats(rxo)->rx_bytes;
+                mcast += rx_stats(rxo)->rx_mcast_pkts;
                 /*  no space in linux buffers: best possible approximation */
                 if (adapter->generation == BE_GEN3) {
                         if (!(lancer_chip(adapter))) {
-                                struct be_erx_stats_v1 *erx_stats =
+                                struct be_erx_stats_v1 *erx =
                                         be_erx_stats_from_cmd(adapter);
-                                dev_stats->rx_dropped +=
-                                erx_stats->rx_drops_no_fragments[rxo->q.id];
+                                drops += erx->rx_drops_no_fragments[rxo->q.id];
                         }
                 } else {
-                        struct be_erx_stats_v0 *erx_stats =
+                        struct be_erx_stats_v0 *erx =
                                         be_erx_stats_from_cmd(adapter);
-                        dev_stats->rx_dropped +=
-                                erx_stats->rx_drops_no_fragments[rxo->q.id];
+                        drops += erx->rx_drops_no_fragments[rxo->q.id];
                 }
         }
+        dev_stats->rx_packets = pkts;
+        dev_stats->rx_bytes = bytes;
+        dev_stats->multicast = mcast;
+        dev_stats->rx_dropped = drops;
 
+        pkts = bytes = 0;
         for_all_tx_queues(adapter, txo, i) {
-                dev_stats->tx_packets += tx_stats(txo)->be_tx_pkts;
-                dev_stats->tx_bytes += tx_stats(txo)->be_tx_bytes;
+                pkts += tx_stats(txo)->be_tx_pkts;
+                bytes += tx_stats(txo)->be_tx_bytes;
         }
+        dev_stats->tx_packets = pkts;
+        dev_stats->tx_bytes = bytes;
 
         /* bad pkts received */
         dev_stats->rx_errors = drvs->rx_crc_errors +