net/axgbe: 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 axgbe 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: 9d1ef6b2e731 ("net/axgbe: add xstats")
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/axgbe/axgbe_ethdev.c b/drivers/net/axgbe/axgbe_ethdev.c
index 951da5cc26ea85ada7ddddea39dca57731dd72bd..e6822fa711e4363fa878743166461b7dcdee7517 100644 (file)
--- 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