veth: Fix veth_get_stats()
Subsystems (2)
PATCH 1/1 veth: Fix veth_get_stats()
veth_get_stats() can be called in parallel on several cpus.
It's better to not reset dev->stats as it could give wrong result on one cpu. Use temporary variables, then store the final results.
Also, we should loop on every possible cpus, not only online cpus, or cpu hotplug can suddenly give wrong veth stats.
Signed-off-by Eric Dumazet <[email protected]>
--- drivers/net/veth.c | 35 ++++++++++++++++------------------- 1 files changed, 16 insertions(+), 19 deletions(-)
drivers/net/veth.c +16 -19
@@ -210,32 +210,29 @@ rx_drop:static struct net_device_stats *veth_get_stats (struct net_device *dev) {struct veth_priv *priv; -struct net_device_stats *dev_stats;int cpu; -struct veth_net_stats *stats; +struct veth_net_stats *stats, total = {0 }; priv =netdev_priv (dev); - dev_stats = &dev->stats; - - dev_stats->rx_packets =0 ; - dev_stats->tx_packets =0 ; - dev_stats->rx_bytes =0 ; - dev_stats->tx_bytes =0 ; - dev_stats->tx_dropped =0 ; - dev_stats->rx_dropped =0 ; -for_each_online_cpu (cpu) { +for_each_possible_cpu (cpu) { stats =per_cpu_ptr (priv->stats, cpu); - dev_stats->rx_packets += stats->rx_packets; - dev_stats->tx_packets += stats->tx_packets; - dev_stats->rx_bytes += stats->rx_bytes; - dev_stats->tx_bytes += stats->tx_bytes; - dev_stats->tx_dropped += stats->tx_dropped; - dev_stats->rx_dropped += stats->rx_dropped; + total.rx_packets += stats->rx_packets; + total.tx_packets += stats->tx_packets; + total.rx_bytes += stats->rx_bytes; + total.tx_bytes += stats->tx_bytes; + total.tx_dropped += stats->tx_dropped; + total.rx_dropped += stats->rx_dropped; } - -return dev_stats; + dev->stats.rx_packets = total.rx_packets; + dev->stats.tx_packets = total.tx_packets; + dev->stats.rx_bytes = total.rx_bytes; + dev->stats.tx_bytes = total.tx_bytes; + dev->stats.tx_dropped = total.tx_dropped; + dev->stats.rx_dropped = total.rx_dropped; + +return &dev->stats; }static int veth_open (struct net_device *dev)
From: Eric Dumazet <[email protected]>
Date: Wed, 18 Nov 2009 18:09:39 +0100
Quoted 9 lines
veth_get_stats()can be called in parallel on several cpus.It's better to not reset
dev->statsas it could give wrong result on one cpu. Use temporary variables, then store the final results.Also, we should loop on every possible cpus, not only online cpus, or cpu hotplug can suddenly give wrong veth stats.
Signed-off-by Eric Dumazet <[email protected]>
Applied.