From ae30c4a7b550e0ac12857279c0a337d80f73261c Mon Sep 17 00:00:00 2001
From: Chengwen Feng <fengchengwen@huawei.com>
Date: Fri, 13 May 2022 10:53:53 +0800
Subject: [PATCH 091/122] net/mvpp2: fix xstats get return if xstats is null
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Many user (e.g. telemetry) invokes rte_eth_xstats_get(port_id, NULL, 0)
to retrieve the required number of elements, but currently mvpp2 PMD
returns zero when xstats is null.

Remove the logic of "return zero when xstats is NULL", and add the logic
of "return the required number of entries when n is lower than the
required number of entries".

Fixes: a77b5378cd41 ("net/mrvl: add extended statistics")
Cc: stable@dpdk.org

Signed-off-by: Chengwen Feng <fengchengwen@huawei.com>
Acked-by: Morten Brørup <mb@smartsharesystems.com>
Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
---
 drivers/net/mvpp2/mrvl_ethdev.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/net/mvpp2/mrvl_ethdev.c b/drivers/net/mvpp2/mrvl_ethdev.c
index 9c7fe13f7f..2a8fb6cbce 100644
--- a/drivers/net/mvpp2/mrvl_ethdev.c
+++ b/drivers/net/mvpp2/mrvl_ethdev.c
@@ -1626,13 +1626,14 @@ mrvl_xstats_get(struct rte_eth_dev *dev,
 {
 	struct mrvl_priv *priv = dev->data->dev_private;
 	struct pp2_ppio_statistics ppio_stats;
-	unsigned int i;
+	unsigned int i, count;
 
-	if (!stats)
-		return 0;
+	count = RTE_DIM(mrvl_xstats_tbl);
+	if (n < count)
+		return count;
 
 	pp2_ppio_get_statistics(priv->ppio, &ppio_stats, 0);
-	for (i = 0; i < n && i < RTE_DIM(mrvl_xstats_tbl); i++) {
+	for (i = 0; i < count; i++) {
 		uint64_t val;
 
 		if (mrvl_xstats_tbl[i].size == sizeof(uint32_t))
@@ -1648,7 +1649,7 @@ mrvl_xstats_get(struct rte_eth_dev *dev,
 		stats[i].value = val;
 	}
 
-	return n;
+	return count;
 }
 
 /**
-- 
2.22.0