[dpdk-dev] [PATCH] net/bnxt: fix to clear cached value of stats in clear stats

[Kalesh A P <kalesh-anakkur.purayil@broadcom.com>]

From: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>

As part of the workaround put in the commit "219842b9990c",
driver caches the last read stats values from the hardware.
But this is not cleared during the clear stats operation. This
results in showing up stale stats values while reading the stats
after the clear operation.

Fixes: 219842b9990c ("net/bnxt: workaround spurious zero stats in Thor")
Cc: stable@dpdk.org

Signed-off-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Reviewed-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
Reviewed-by: Lance Richardson <lance.richardson@broadcom.com>
Reviewed-by: Somnath Kotur <somnath.kotur@broadcom.com>
---
 drivers/net/bnxt/bnxt_stats.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/net/bnxt/bnxt_stats.c b/drivers/net/bnxt/bnxt_stats.c
index c7b23f4..991eafc 100644
--- a/drivers/net/bnxt/bnxt_stats.c
+++ b/drivers/net/bnxt/bnxt_stats.c
@@ -603,6 +603,16 @@ int bnxt_stats_get_op(struct rte_eth_dev *eth_dev,
 	return rc;
 }
 
+static void bnxt_clear_prev_stat(struct bnxt *bp)
+{
+	/*
+	 * Clear the cached values of stats returned by HW in the previous
+	 * get operation.
+	 */
+	memset(bp->prev_rx_ring_stats, 0, sizeof(struct bnxt_ring_stats) * bp->rx_cp_nr_rings);
+	memset(bp->prev_tx_ring_stats, 0, sizeof(struct bnxt_ring_stats) * bp->tx_cp_nr_rings);
+}
+
 int bnxt_stats_reset_op(struct rte_eth_dev *eth_dev)
 {
 	struct bnxt *bp = eth_dev->data->dev_private;
@@ -625,6 +635,8 @@ int bnxt_stats_reset_op(struct rte_eth_dev *eth_dev)
 		rte_atomic64_clear(&rxq->rx_mbuf_alloc_fail);
 	}
 
+	bnxt_clear_prev_stat(bp);
+
 	return ret;
 }
 
@@ -933,6 +945,8 @@ int bnxt_dev_xstats_reset_op(struct rte_eth_dev *eth_dev)
 		PMD_DRV_LOG(ERR, "Failed to reset xstats: %s\n",
 			    strerror(-ret));
 
+	bnxt_clear_prev_stat(bp);
+
 	return ret;
 }
 
-- 
2.10.1