diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c
index f94711caa08..9197b2c72ca 100644
--- a/drivers/net/usb/cdc_ncm.c
+++ b/drivers/net/usb/cdc_ncm.c
@@ -344,23 +344,6 @@ static const struct ethtool_ops cdc_ncm_ethtool_ops = {
 	.nway_reset = usbnet_nway_reset,
 };
 
-/* return first slave interface if an IAD matches the given master */
-static struct usb_interface *get_iad_slave(struct usb_device *udev,
-					   struct usb_interface *master) {
-	int i;
-	struct usb_interface_assoc_descriptor *iad;
-	u8 mnum = master->cur_altsetting->desc.bInterfaceNumber;
-
-	for (i = 0; i < USB_MAXIADS; i++) {
-		iad = udev->actconfig->intf_assoc[i];
-		if (!iad)
-			break;
-		if (iad->bFirstInterface == mnum && iad->bInterfaceCount == 2)
-			return usb_ifnum_to_if(udev, mnum + 1);
-	}
-	return NULL;
-}
-
 int cdc_ncm_bind_common(struct usbnet *dev, struct usb_interface *intf, u8 data_altsetting)
 {
 	struct cdc_ncm_ctx *ctx;
@@ -453,13 +436,10 @@ advance:
 	}
 
 	/* some buggy devices have an IAD but no CDC Union */
-	if (!ctx->union_desc) {
-		dev_dbg(&intf->dev, "missing CDC Union descriptor\n");
-		ctx->data = get_iad_slave(dev->udev, intf);
-		if (ctx->data) {
-			ctx->control = intf;
-			dev_dbg(&intf->dev, "got slave from IAD\n");
-		}
+	if (!ctx->union_desc && intf->intf_assoc && intf->intf_assoc->bInterfaceCount == 2) {
+		ctx->control = intf;
+		ctx->data = usb_ifnum_to_if(dev->udev, intf->cur_altsetting->desc.bInterfaceNumber + 1);
+		dev_dbg(&intf->dev, "CDC Union missing - got slave from IAD\n");
 	}
 
 	/* check if we got everything */