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From:   Albert Huang <huangjie.albert@bytedance.com>
To:     Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>
Cc:     Albert Huang <huangjie.albert@bytedance.com>,
        "David S. Miller" <davem@davemloft.net>,
        Toshiaki Makita <toshiaki.makita1@gmail.com>,
        Lorenzo Bianconi <lorenzo@kernel.org>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH net] veth: fix ethtool statistical errors
Date:   Thu, 16 Nov 2023 19:41:50 +0800
Message-Id: <20231116114150.48639-1-huangjie.albert@bytedance.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

if peer->real_num_rx_queues > 1, the ethtool -s command for
veth network device will display some error statistical values.
The value of tx_idx is reset with each iteration, so even if
peer->real_num_rx_queues is greater than 1, the value of tx_idx
will remain constant. This results in incorrect statistical values.
To fix this issue, assign the value of pp_idx to tx_idx.

Fixes: 5fe6e56776ba ("veth: rely on peer veth_rq for ndo_xdp_xmit accounting")
Signed-off-by: Albert Huang <huangjie.albert@bytedance.com>
---
 drivers/net/veth.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index 0deefd1573cf..3a8e3fc5eeb5 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -225,7 +225,7 @@ static void veth_get_ethtool_stats(struct net_device *dev,
 	for (i = 0; i < peer->real_num_rx_queues; i++) {
 		const struct veth_rq_stats *rq_stats = &rcv_priv->rq[i].stats;
 		const void *base = (void *)&rq_stats->vs;
-		unsigned int start, tx_idx = idx;
+		unsigned int start, tx_idx = pp_idx;
 		size_t offset;
 
 		tx_idx += (i % dev->real_num_tx_queues) * VETH_TQ_STATS_LEN;
-- 
2.20.1