patch 'net/hns3: 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/17467579f79a4f9825a307a189d86c123b29d259

Thanks.

Xueming Li <xuemingl at nvidia.com>

---
>From 17467579f79a4f9825a307a189d86c123b29d259 Mon Sep 17 00:00:00 2001
From: Chengwen Feng <fengchengwen at huawei.com>
Date: Fri, 13 May 2022 10:53:51 +0800
Subject: [PATCH] net/hns3: 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 e15401f362779dba8623b4ee3db388fdf79dca7f ]

Many user (e.g. telemetry) invokes rte_eth_xstats_get(port_id, NULL, 0)
to retrieve the required number of elements, but currently hns3 PMD
returns zero when xstats is null.

Dedicated check for xstats vs null is not required, since ethdev layer
guarantees that it may be null only if number of entries n is 0 (which
is definitely smaller than total xstats count).

Fixes: 8839c5e202f3 ("net/hns3: support device stats")

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/hns3/hns3_stats.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/net/hns3/hns3_stats.c b/drivers/net/hns3/hns3_stats.c
index 04702f17d1..3cb1e4cac1 100644
--- a/drivers/net/hns3/hns3_stats.c
+++ b/drivers/net/hns3/hns3_stats.c
@@ -694,9 +694,13 @@ hns3_error_int_stats_add(struct hns3_adapter *hns, const char *err)
  * @praram xstats
  *   A pointer to a table of structure of type *rte_eth_xstat*
  *   to be filled with device statistics ids and values.
- *   This parameter can be set to NULL if n is 0.
+ *   This parameter can be set to NULL if and only if n is 0.
  * @param n
  *   The size of the xstats array (number of elements).
+ *   If lower than the required number of elements, the function returns the
+ *   required number of elements.
+ *   If equal to zero, the xstats parameter must be NULL, the function returns
+ *   the required number of elements.
  * @return
  *   0 on fail, count(The size of the statistics elements) on success.
  */
@@ -716,9 +720,6 @@ hns3_dev_xstats_get(struct rte_eth_dev *dev, struct rte_eth_xstat *xstats,
 	int count;
 	int ret;
 
-	if (xstats == NULL)
-		return 0;
-
 	count = hns3_xstats_calc_num(dev);
 	if ((int)n < count)
 		return count;
-- 
2.35.1

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2022-06-21 15:37:52.511593306 +0800
+++ 0071-net-hns3-fix-xstats-get-return-if-xstats-is-null.patch	2022-06-21 15:37:49.107784833 +0800
@@ -1 +1 @@
-From e15401f362779dba8623b4ee3db388fdf79dca7f Mon Sep 17 00:00:00 2001
+From 17467579f79a4f9825a307a189d86c123b29d259 Mon Sep 17 00:00:00 2001
@@ -7,0 +8,3 @@
+Cc: Xueming Li <xuemingl at nvidia.com>
+
+[ upstream commit e15401f362779dba8623b4ee3db388fdf79dca7f ]
@@ -18 +20,0 @@
-Cc: stable at dpdk.org
@@ -28 +30 @@
-index 2799ff4432..07fad03485 100644
+index 04702f17d1..3cb1e4cac1 100644
@@ -31 +33 @@
-@@ -1031,9 +1031,13 @@ hns3_imissed_stats_get(struct rte_eth_dev *dev, struct rte_eth_xstat *xstats,
+@@ -694,9 +694,13 @@ hns3_error_int_stats_add(struct hns3_adapter *hns, const char *err)
@@ -46 +48 @@
-@@ -1052,9 +1056,6 @@ hns3_dev_xstats_get(struct rte_eth_dev *dev, struct rte_eth_xstat *xstats,
+@@ -716,9 +720,6 @@ hns3_dev_xstats_get(struct rte_eth_dev *dev, struct rte_eth_xstat *xstats,