net/mvpp2: fix xstats get return if xstats is null

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>

diff --git a/drivers/net/mvpp2/mrvl_ethdev.c b/drivers/net/mvpp2/mrvl_ethdev.c
index f86701d24886a958518181dd3d8d9ef4d3fc1287..735efb6cfc06c714bc86687241241637ff5c3857 100644 (file)
--- 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;
 }
 
 /**