r8152: change rx early size when the mtu is changed

The rx early size is calculated with the mtu, so it has to be
re-calculated when the mtu is changed.

Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/usb/r8152.c

@@ -3777,6 +3777,7 @@ static int rtl8152_ioctl(struct net_device *netdev, struct ifreq *rq, int cmd)
 static int rtl8152_change_mtu(struct net_device *dev, int new_mtu)
 {
 	struct r8152 *tp = netdev_priv(dev);
+	int ret;
 
 	switch (tp->version) {
 	case RTL_VER_01:
@@ -3789,9 +3790,22 @@ static int rtl8152_change_mtu(struct net_device *dev, int new_mtu)
 	if (new_mtu < 68 || new_mtu > RTL8153_MAX_MTU)
 		return -EINVAL;
 
+	ret = usb_autopm_get_interface(tp->intf);
+	if (ret < 0)
+		return ret;
+
+	mutex_lock(&tp->control);
+
 	dev->mtu = new_mtu;
 
-	return 0;
+	if (netif_running(dev) && netif_carrier_ok(dev))
+		r8153_set_rx_early_size(tp);
+
+	mutex_unlock(&tp->control);
+
+	usb_autopm_put_interface(tp->intf);
+
+	return ret;
 }
 
 static const struct net_device_ops rtl8152_netdev_ops = {