[PATCH v4 6/9] net/axgbe: adjust return value of xstats-get ops

[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 axgbe PMD
returns zero when xstats is NULL.

In the previous patch, the framework defines that the required number
of entries should be returned when n is lower than the required number
of entries, and makes sure xstats must not be NULL when n is non-zero.

This patch removes the logic of "return zero when xstats is NULL", and
adds the logic of "return the required number of entries when n is
lower than the required number of entries".

Fixes: 9d1ef6b2e731 ("net/axgbe: add xstats")
Cc: stable at dpdk.org

Signed-off-by: Chengwen Feng <fengchengwen at huawei.com>
---
 drivers/net/axgbe/axgbe_ethdev.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/net/axgbe/axgbe_ethdev.c b/drivers/net/axgbe/axgbe_ethdev.c
index 951da5cc26..e6822fa711 100644
--- a/drivers/net/axgbe/axgbe_ethdev.c
+++ b/drivers/net/axgbe/axgbe_ethdev.c
@@ -1013,18 +1013,18 @@ axgbe_dev_xstats_get(struct rte_eth_dev *dev, struct rte_eth_xstat *stats,
 	struct axgbe_port *pdata = dev->data->dev_private;
 	unsigned int i;
 
-	if (!stats)
-		return 0;
+	if (n < AXGBE_XSTATS_COUNT)
+		return AXGBE_XSTATS_COUNT;
 
 	axgbe_read_mmc_stats(pdata);
 
-	for (i = 0; i < n && i < AXGBE_XSTATS_COUNT; i++) {
+	for (i = 0; i < AXGBE_XSTATS_COUNT; i++) {
 		stats[i].id = i;
 		stats[i].value = *(u64 *)((uint8_t *)&pdata->mmc_stats +
 				axgbe_xstats_strings[i].offset);
 	}
 
-	return i;
+	return AXGBE_XSTATS_COUNT;
 }
 
 static int
-- 
2.33.0