patch 'net/mvpp2: fix xstats get return if xstats is null' has been queued to stable release 20.11.6

[Xueming Li]

Hi,

FYI, your patch has been queued to stable release 20.11.6

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 06/23/22. So please
shout if anyone has objections.

Also note that after the patch there's a diff of the upstream commit vs the
patch applied to the branch. This will indicate if there was any rebasing
needed to apply to the stable branch. If there were code changes for rebasing
(ie: not only metadata diffs), please double check that the rebase was
correctly done.

Queued patches are on a temporary branch at:
https://github.com/steevenlee/dpdk

This queued commit can be viewed at:
https://github.com/steevenlee/dpdk/commit/2b88b790c13c872f1de308ccf9ea120b27dc5666

Thanks.

Xueming Li <xuemingl at nvidia.com>

---
>From 2b88b790c13c872f1de308ccf9ea120b27dc5666 Mon Sep 17 00:00:00 2001
From: Chengwen Feng <fengchengwen at huawei.com>
Date: Fri, 13 May 2022 10:53:53 +0800
Subject: [PATCH] net/mvpp2: fix xstats get return if xstats is null
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Cc: Xueming Li <xuemingl at nvidia.com>

[ upstream commit d853d24b27d6524f26a2a830c7ef678ba739cfce ]

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")

Signed-off-by: Chengwen Feng <fengchengwen at huawei.com>
Acked-by: Morten Brørup <mb at smartsharesystems.com>
Reviewed-by: Andrew Rybchenko <andrew.rybchenko at 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 ce077c4ecd..09af452abe 100644
--- a/drivers/net/mvpp2/mrvl_ethdev.c
+++ b/drivers/net/mvpp2/mrvl_ethdev.c
@@ -1376,13 +1376,14 @@ 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))
@@ -1398,7 +1399,7 @@ mrvl_xstats_get(struct rte_eth_dev *dev,
 		stats[i].value = val;
 	}
 
-	return n;
+	return count;
 }
 
 /**
-- 
2.35.1

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2022-06-21 15:37:52.589867491 +0800
+++ 0073-net-mvpp2-fix-xstats-get-return-if-xstats-is-null.patch	2022-06-21 15:37:49.111118179 +0800
@@ -1 +1 @@
-From d853d24b27d6524f26a2a830c7ef678ba739cfce Mon Sep 17 00:00:00 2001
+From 2b88b790c13c872f1de308ccf9ea120b27dc5666 Mon Sep 17 00:00:00 2001
@@ -7,0 +8,3 @@
+Cc: Xueming Li <xuemingl at nvidia.com>
+
+[ upstream commit d853d24b27d6524f26a2a830c7ef678ba739cfce ]
@@ -18 +20,0 @@
-Cc: stable at dpdk.org
@@ -28 +30 @@
-index f86701d248..735efb6cfc 100644
+index ce077c4ecd..09af452abe 100644
@@ -31 +33 @@
-@@ -1626,13 +1626,14 @@ mrvl_xstats_get(struct rte_eth_dev *dev,
+@@ -1376,13 +1376,14 @@ mrvl_xstats_get(struct rte_eth_dev *dev,
@@ -50 +52 @@
-@@ -1648,7 +1649,7 @@ mrvl_xstats_get(struct rte_eth_dev *dev,
+@@ -1398,7 +1399,7 @@ mrvl_xstats_get(struct rte_eth_dev *dev,