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Date: Mon, 20 Jun 2011 07:46:12 +0200
From: Eric Dumazet <eric.dumazet@...il.com>
To: David Miller <davem@...emloft.net>
Cc: netdev <netdev@...r.kernel.org>,
Stephen Hemminger <shemminger@...tta.com>,
Jeff Kirsher <jeffrey.t.kirsher@...el.com>
Subject: [PATCH net-next-2.6] veth: fix 64bit stats on 32bit arches
Using 64bit stats on 32bit arches must use a synchronization or readers
can get transient values.
Fixes bug introduced in commit 6311cc44a2 (veth: convert to 64 bit
statistics)
Signed-off-by: Eric Dumazet <eric.dumazet@...il.com>
CC: Stephen Hemminger <shemminger@...tta.com>
CC: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
---
drivers/net/veth.c | 55 ++++++++++++++++++++++++++++---------------
1 file changed, 37 insertions(+), 18 deletions(-)
diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index 8730d64..8acb3af 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -12,6 +12,7 @@
#include <linux/slab.h>
#include <linux/ethtool.h>
#include <linux/etherdevice.h>
+#include <linux/u64_stats_sync.h>
#include <net/dst.h>
#include <net/xfrm.h>
@@ -24,12 +25,13 @@
#define MAX_MTU 65535 /* Max L3 MTU (arbitrary) */
struct veth_net_stats {
- u64 rx_packets;
- u64 tx_packets;
- u64 rx_bytes;
- u64 tx_bytes;
- u64 tx_dropped;
- u64 rx_dropped;
+ u64 rx_packets;
+ u64 tx_packets;
+ u64 rx_bytes;
+ u64 tx_bytes;
+ u64 rx_dropped;
+ u64 tx_dropped;
+ struct u64_stats_sync syncp;
};
struct veth_priv {
@@ -137,21 +139,29 @@ static netdev_tx_t veth_xmit(struct sk_buff *skb, struct net_device *dev)
if (dev_forward_skb(rcv, skb) != NET_RX_SUCCESS)
goto rx_drop;
+ u64_stats_update_begin(&stats->syncp);
stats->tx_bytes += length;
stats->tx_packets++;
+ u64_stats_update_end(&stats->syncp);
+ u64_stats_update_begin(&rcv_stats->syncp);
rcv_stats->rx_bytes += length;
rcv_stats->rx_packets++;
+ u64_stats_update_end(&rcv_stats->syncp);
return NETDEV_TX_OK;
tx_drop:
kfree_skb(skb);
+ u64_stats_update_begin(&stats->syncp);
stats->tx_dropped++;
+ u64_stats_update_end(&stats->syncp);
return NETDEV_TX_OK;
rx_drop:
+ u64_stats_update_begin(&rcv_stats->syncp);
rcv_stats->rx_dropped++;
+ u64_stats_update_end(&rcv_stats->syncp);
return NETDEV_TX_OK;
}
@@ -162,21 +172,30 @@ rx_drop:
static struct rtnl_link_stats64 *veth_get_stats64(struct net_device *dev,
struct rtnl_link_stats64 *tot)
{
- struct veth_priv *priv;
+ struct veth_priv *priv = netdev_priv(dev);
int cpu;
- struct veth_net_stats *stats;
-
- priv = netdev_priv(dev);
for_each_possible_cpu(cpu) {
- stats = per_cpu_ptr(priv->stats, cpu);
-
- tot->rx_packets += stats->rx_packets;
- tot->tx_packets += stats->tx_packets;
- tot->rx_bytes += stats->rx_bytes;
- tot->tx_bytes += stats->tx_bytes;
- tot->tx_dropped += stats->tx_dropped;
- tot->rx_dropped += stats->rx_dropped;
+ struct veth_net_stats *stats = per_cpu_ptr(priv->stats, cpu);
+ u64 rx_packets, rx_bytes, rx_dropped;
+ u64 tx_packets, tx_bytes, tx_dropped;
+ unsigned int start;
+
+ do {
+ start = u64_stats_fetch_begin_bh(&stats->syncp);
+ rx_packets = stats->rx_packets;
+ tx_packets = stats->tx_packets;
+ rx_bytes = stats->rx_bytes;
+ tx_bytes = stats->tx_bytes;
+ rx_dropped = stats->rx_dropped;
+ tx_dropped = stats->tx_dropped;
+ } while (u64_stats_fetch_retry_bh(&stats->syncp, start));
+ tot->rx_packets += rx_packets;
+ tot->tx_packets += tx_packets;
+ tot->rx_bytes += rx_bytes;
+ tot->tx_bytes += tx_bytes;
+ tot->rx_dropped += rx_dropped;
+ tot->tx_dropped += tx_dropped;
}
return tot;
--
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