nfp: add helper for printing ethtool strings

Add a helper for printing ethtool strings and advancing the
pointer correctly.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/netronome/nfp/nfp_net_ethtool.c

@@ -335,53 +335,52 @@ static int nfp_net_set_ringparam(struct net_device *netdev,
 	return nfp_net_set_ring_size(nn, rxd_cnt, txd_cnt);
 }
 
+static __printf(2, 3) u8 *nfp_pr_et(u8 *data, const char *fmt, ...)
+{
+	va_list args;
+
+	va_start(args, fmt);
+	vsnprintf(data, ETH_GSTRING_LEN, fmt, args);
+	va_end(args);
+
+	return data + ETH_GSTRING_LEN;
+}
+
 static void nfp_net_get_strings(struct net_device *netdev,
 				u32 stringset, u8 *data)
 {
 	struct nfp_net *nn = netdev_priv(netdev);
-	u8 *p = data;
 	int i;
 
 	switch (stringset) {
 	case ETH_SS_STATS:
-		for (i = 0; i < NN_ET_GLOBAL_STATS_LEN; i++) {
-			memcpy(p, nfp_net_et_stats[i].name, ETH_GSTRING_LEN);
-			p += ETH_GSTRING_LEN;
-		}
+		for (i = 0; i < NN_ET_GLOBAL_STATS_LEN; i++)
+			data = nfp_pr_et(data, nfp_net_et_stats[i].name);
+
 		for (i = 0; i < nn->dp.num_r_vecs; i++) {
-			sprintf(p, "rvec_%u_rx_pkts", i);
-			p += ETH_GSTRING_LEN;
-			sprintf(p, "rvec_%u_tx_pkts", i);
-			p += ETH_GSTRING_LEN;
-			sprintf(p, "rvec_%u_tx_busy", i);
-			p += ETH_GSTRING_LEN;
+			data = nfp_pr_et(data, "rvec_%u_rx_pkts", i);
+			data = nfp_pr_et(data, "rvec_%u_tx_pkts", i);
+			data = nfp_pr_et(data, "rvec_%u_tx_busy", i);
 		}
-		strncpy(p, "hw_rx_csum_ok", ETH_GSTRING_LEN);
-		p += ETH_GSTRING_LEN;
-		strncpy(p, "hw_rx_csum_inner_ok", ETH_GSTRING_LEN);
-		p += ETH_GSTRING_LEN;
-		strncpy(p, "hw_rx_csum_err", ETH_GSTRING_LEN);
-		p += ETH_GSTRING_LEN;
-		strncpy(p, "hw_tx_csum", ETH_GSTRING_LEN);
-		p += ETH_GSTRING_LEN;
-		strncpy(p, "hw_tx_inner_csum", ETH_GSTRING_LEN);
-		p += ETH_GSTRING_LEN;
-		strncpy(p, "tx_gather", ETH_GSTRING_LEN);
-		p += ETH_GSTRING_LEN;
-		strncpy(p, "tx_lso", ETH_GSTRING_LEN);
-		p += ETH_GSTRING_LEN;
+
+		data = nfp_pr_et(data, "hw_rx_csum_ok");
+		data = nfp_pr_et(data, "hw_rx_csum_inner_ok");
+		data = nfp_pr_et(data, "hw_rx_csum_err");
+		data = nfp_pr_et(data, "hw_tx_csum");
+		data = nfp_pr_et(data, "hw_tx_inner_csum");
+		data = nfp_pr_et(data, "tx_gather");
+		data = nfp_pr_et(data, "tx_lso");
+
 		for (i = 0; i < nn->dp.num_tx_rings; i++) {
-			sprintf(p, "txq_%u_pkts", i);
-			p += ETH_GSTRING_LEN;
-			sprintf(p, "txq_%u_bytes", i);
-			p += ETH_GSTRING_LEN;
+			data = nfp_pr_et(data, "txq_%u_pkts", i);
+			data = nfp_pr_et(data, "txq_%u_bytes", i);
 		}
+
 		for (i = 0; i < nn->dp.num_rx_rings; i++) {
-			sprintf(p, "rxq_%u_pkts", i);
-			p += ETH_GSTRING_LEN;
-			sprintf(p, "rxq_%u_bytes", i);
-			p += ETH_GSTRING_LEN;
+			data = nfp_pr_et(data, "rxq_%u_pkts", i);
+			data = nfp_pr_et(data, "rxq_%u_bytes", i);
 		}
+
 		break;
 	}
 }