loopback: packet drops accounting
We can in some situations drop packets in netif_rx()
loopback driver does not report these (unlikely) drops to its stats,
and incorrectly change packets/bytes counts.
After this patch applied, "ifconfig lo" can reports these drops as in :
# ifconfig lo
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:692562900 errors:3228 dropped:3228 overruns:0 frame:0
TX packets:692562900 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:2865674174 (2.6 GiB) TX bytes:2865674174 (2.6 GiB)
I initialy chose to reflect those errors only in tx_dropped/tx_errors, but David
convinced me that it was really RX errors, as loopback_xmit() really starts
a RX process. (calling eth_type_trans() for example, that itself pulls the ethernet header)
These errors are accounted in rx_dropped/rx_errors.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c
index b7d438a..6f71157 100644
--- a/drivers/net/loopback.c
+++ b/drivers/net/loopback.c
@@ -62,6 +62,7 @@
struct pcpu_lstats {
unsigned long packets;
unsigned long bytes;
+ unsigned long drops;
};
/*
@@ -71,18 +72,22 @@
static int loopback_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct pcpu_lstats *pcpu_lstats, *lb_stats;
+ int len;
skb_orphan(skb);
- skb->protocol = eth_type_trans(skb,dev);
+ skb->protocol = eth_type_trans(skb, dev);
/* it's OK to use per_cpu_ptr() because BHs are off */
pcpu_lstats = dev->ml_priv;
lb_stats = per_cpu_ptr(pcpu_lstats, smp_processor_id());
- lb_stats->bytes += skb->len;
- lb_stats->packets++;
- netif_rx(skb);
+ len = skb->len;
+ if (likely(netif_rx(skb) == NET_RX_SUCCESS)) {
+ lb_stats->bytes += len;
+ lb_stats->packets++;
+ } else
+ lb_stats->drops++;
return 0;
}
@@ -93,6 +98,7 @@
struct net_device_stats *stats = &dev->stats;
unsigned long bytes = 0;
unsigned long packets = 0;
+ unsigned long drops = 0;
int i;
pcpu_lstats = dev->ml_priv;
@@ -102,11 +108,14 @@
lb_stats = per_cpu_ptr(pcpu_lstats, i);
bytes += lb_stats->bytes;
packets += lb_stats->packets;
+ drops += lb_stats->drops;
}
stats->rx_packets = packets;
stats->tx_packets = packets;
- stats->rx_bytes = bytes;
- stats->tx_bytes = bytes;
+ stats->rx_dropped = drops;
+ stats->rx_errors = drops;
+ stats->rx_bytes = bytes;
+ stats->tx_bytes = bytes;
return stats;
}
