net/bnxt: fix xstats get

[ upstream commit eac4fc7 ]

Fix to return count in xstats get op in all cases.
Driver was returning 0 if the 'xstats' parameter being passed to
xstats_get_op was NULL. This won't work on some applications that
rely on a valid count being passed even in this case so that it can
allocate memory accordingly followed by a reissue of the xstats_get_op
to get the actual stats populated by the driver.

Fixes: 063e59d ("net/bnxt: fix crash in xstats get")

Reviewed-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Reviewed-by: Lance Richardson <lance.richardson@broadcom.com>
Reviewed-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
Signed-off-by: Somnath Kotur <somnath.kotur@broadcom.com>

drivers/net/bnxt/bnxt_stats.c

@@ -594,10 +594,15 @@ int bnxt_dev_xstats_get_op(struct rte_eth_dev *eth_dev,
 	if (rc)
 		return rc;
 
-	if (xstats == NULL)
-		return 0;
+	stat_count = RTE_DIM(bnxt_rx_stats_strings) +
+		RTE_DIM(bnxt_tx_stats_strings) +
+		RTE_DIM(bnxt_func_stats_strings) +
+		RTE_DIM(bnxt_rx_ext_stats_strings) +
+		RTE_DIM(bnxt_tx_ext_stats_strings) +
+		bnxt_flow_stats_cnt(bp);
 
-	memset(xstats, 0, sizeof(*xstats));
+	if (n < stat_count || xstats == NULL)
+		return stat_count;
 
 	bnxt_hwrm_func_qstats(bp, 0xffff, NULL, &func_qstats);
 	bnxt_hwrm_port_qstats(bp);
@@ -609,17 +614,7 @@ int bnxt_dev_xstats_get_op(struct rte_eth_dev *eth_dev,
 					(bp->fw_tx_port_stats_ext_size /
 					 stat_size));
 
-	count = RTE_DIM(bnxt_rx_stats_strings) +
-		RTE_DIM(bnxt_tx_stats_strings) +
-		RTE_DIM(bnxt_func_stats_strings) +
-		RTE_DIM(bnxt_rx_ext_stats_strings) +
-		RTE_DIM(bnxt_tx_ext_stats_strings) +
-		bnxt_flow_stats_cnt(bp);
-
-	stat_count = count;
-
-	if (n < count)
-		return count;
+	memset(xstats, 0, sizeof(*xstats));
 
 	count = 0;
 	for (i = 0; i < RTE_DIM(bnxt_rx_stats_strings); i++) {