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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Shay Agroskin <shayagr@amazon.com>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 5.7 10/15] net: ena: Make missed_tx stat incremental
Date:   Wed, 26 Aug 2020 14:02:38 +0200
Message-Id: <20200826114849.800823726@linuxfoundation.org>
In-Reply-To: <20200826114849.295321031@linuxfoundation.org>
References: <20200826114849.295321031@linuxfoundation.org>
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From: Shay Agroskin <shayagr@amazon.com>

[ Upstream commit ccd143e5150f24b9ba15145c7221b61dd9e41021 ]

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/amazon/ena/ena_netdev.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/amazon/ena/ena_netdev.c
+++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c
@@ -3594,7 +3594,7 @@ static int check_missing_comp_in_tx_queu
 	}
 
 	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;
@@ -4519,6 +4519,9 @@ static void ena_keep_alive_wd(void *adap
 	rx_drops = ((u64)desc->rx_drops_high << 32) | desc->rx_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;
 	u64_stats_update_end(&adapter->syncp);
 }