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authorAlex Elder <elder@linaro.org>2021-06-11 13:26:00 -0500
committerDavid S. Miller <davem@davemloft.net>2021-06-14 12:13:38 -0700
commit994c393bb6886d6d94d628475b274a8cb3fc67a4 (patch)
tree36f896c2133b667725d3726a8abe619e4a3c0a3c /drivers/net
parent4f667b8e049e716a0533fc927f50310fe6e40d22 (diff)
net: qualcomm: rmnet: don't over-count statistics
The purpose of the loop using u64_stats_fetch_*_irq() is to ensure statistics on a given CPU are collected atomically. If one of the statistics values gets updated within the begin/retry window, the loop will run again. Currently the statistics totals are updated inside that window. This means that if the loop ever retries, the statistics for the CPU will be counted more than once. Fix this by taking a snapshot of a CPU's statistics inside the protected window, and then updating the counters with the snapshot values after exiting the loop. (Also add a newline at the end of this file...) Fixes: 192c4b5d48f2a ("net: qualcomm: rmnet: Add support for 64 bit stats") Signed-off-by: Alex Elder <elder@linaro.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net')
-rw-r--r--drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c18
1 files changed, 9 insertions, 9 deletions
diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c
index 41fbd2ceeede..ab1e0fcccabb 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c
@@ -126,24 +126,24 @@ static void rmnet_get_stats64(struct net_device *dev,
struct rtnl_link_stats64 *s)
{
struct rmnet_priv *priv = netdev_priv(dev);
- struct rmnet_vnd_stats total_stats;
+ struct rmnet_vnd_stats total_stats = { };
struct rmnet_pcpu_stats *pcpu_ptr;
+ struct rmnet_vnd_stats snapshot;
unsigned int cpu, start;
- memset(&total_stats, 0, sizeof(struct rmnet_vnd_stats));
-
for_each_possible_cpu(cpu) {
pcpu_ptr = per_cpu_ptr(priv->pcpu_stats, cpu);
do {
start = u64_stats_fetch_begin_irq(&pcpu_ptr->syncp);
- total_stats.rx_pkts += pcpu_ptr->stats.rx_pkts;
- total_stats.rx_bytes += pcpu_ptr->stats.rx_bytes;
- total_stats.tx_pkts += pcpu_ptr->stats.tx_pkts;
- total_stats.tx_bytes += pcpu_ptr->stats.tx_bytes;
+ snapshot = pcpu_ptr->stats; /* struct assignment */
} while (u64_stats_fetch_retry_irq(&pcpu_ptr->syncp, start));
- total_stats.tx_drops += pcpu_ptr->stats.tx_drops;
+ total_stats.rx_pkts += snapshot.rx_pkts;
+ total_stats.rx_bytes += snapshot.rx_bytes;
+ total_stats.tx_pkts += snapshot.tx_pkts;
+ total_stats.tx_bytes += snapshot.tx_bytes;
+ total_stats.tx_drops += snapshot.tx_drops;
}
s->rx_packets = total_stats.rx_pkts;
@@ -354,4 +354,4 @@ int rmnet_vnd_update_dev_mtu(struct rmnet_port *port,
}
return 0;
-} \ No newline at end of file
+}