net: dsa: use new function dev_fetch_sw_netstats

Simplify the code by using new function dev_fetch_sw_netstats().
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Tested-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/b6047017-8226-6b7e-a3cd-064e69fdfa27@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/dsa/slave.c

@@ -1221,28 +1221,9 @@ static void dsa_slave_get_stats64(struct net_device *dev,
 				  struct rtnl_link_stats64 *stats)
 {
 	struct dsa_slave_priv *p = netdev_priv(dev);
-	struct pcpu_sw_netstats *s;
-	unsigned int start;
-	int i;
 
 	netdev_stats_to_stats64(stats, &dev->stats);
-	for_each_possible_cpu(i) {
-		u64 tx_packets, tx_bytes, rx_packets, rx_bytes;
-
-		s = per_cpu_ptr(p->stats64, i);
-		do {
-			start = u64_stats_fetch_begin_irq(&s->syncp);
-			tx_packets = s->tx_packets;
-			tx_bytes = s->tx_bytes;
-			rx_packets = s->rx_packets;
-			rx_bytes = s->rx_bytes;
-		} while (u64_stats_fetch_retry_irq(&s->syncp, start));
-
-		stats->tx_packets += tx_packets;
-		stats->tx_bytes += tx_bytes;
-		stats->rx_packets += rx_packets;
-		stats->rx_bytes += rx_bytes;
-	}
+	dev_fetch_sw_netstats(stats, p->stats64);
 }
 
 static int dsa_slave_get_rxnfc(struct net_device *dev,