[PATCH v3 03/10] net/hns3: adjust retval when xstats is null of get xstats

[Chengwen Feng]

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.

This patch adjusts that the return value was the required number of
elements when stats is NULL.

Fixes: 8839c5e202f3 ("net/hns3: support device stats")
Cc: stable at dpdk.org

Signed-off-by: Chengwen Feng <fengchengwen at huawei.com>
---
 drivers/net/hns3/hns3_stats.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/net/hns3/hns3_stats.c b/drivers/net/hns3/hns3_stats.c
index 806720faff..4165e22f7f 100644
--- a/drivers/net/hns3/hns3_stats.c
+++ b/drivers/net/hns3/hns3_stats.c
@@ -1020,7 +1020,7 @@ hns3_imissed_stats_get(struct rte_eth_dev *dev, struct rte_eth_xstat *xstats,
  * @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.
+ *   If set to NULL, the function returns the required number of elements.
  * @param n
  *   The size of the xstats array (number of elements).
  * @return
@@ -1041,11 +1041,8 @@ 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)
+	if (xstats == NULL || (int)n < count)
 		return count;
 
 	count = 0;
-- 
2.33.0