net: ena: Make missed_tx stat incremental

Most statistics in ena driver are incremented, meaning that a stat's
value is a sum of all increases done to it since driver/queue
initialization.

This patch makes all statistics this way, effectively making missed_tx
statistic incremental.
Also added a comment regarding rx_drops and tx_drops to make it
clearer how these counters are calculated.

Fixes: 11095fdb712b ("net: ena: add statistics for missed tx packets")
Signed-off-by: Shay Agroskin <shayagr@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c b/drivers/net/ethernet/amazon/ena/ena_netdev.c
index 233db15..a3a8edf 100644 (file)
--- a/drivers/net/ethernet/amazon/ena/ena_netdev.c
+++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c
@@ -3687,7 +3687,7 @@ static int check_missing_comp_in_tx_queue(struct ena_adapter *adapter,
        }
 
        u64_stats_update_begin(&tx_ring->syncp);
-       tx_ring->tx_stats.missed_tx = missed_tx;
+       tx_ring->tx_stats.missed_tx += missed_tx;
        u64_stats_update_end(&tx_ring->syncp);
 
        return rc;
@@ -4556,6 +4556,9 @@ static void ena_keep_alive_wd(void *adapter_data,
        tx_drops = ((u64)desc->tx_drops_high << 32) | desc->tx_drops_low;
 
        u64_stats_update_begin(&adapter->syncp);
+       /* These stats are accumulated by the device, so the counters indicate
+        * all drops since last reset.
+        */
        adapter->dev_stats.rx_drops = rx_drops;
        adapter->dev_stats.tx_drops = tx_drops;
        u64_stats_update_end(&adapter->syncp);