static int __usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
			     u16 value, u16 index, void *data, u16 size)
{
	void *buf = NULL;
	int err = -ENOMEM;

	netdev_dbg(dev->net, "usbnet_read_cmd cmd=0x%02x reqtype=%02x"
		   " value=0x%04x index=0x%04x size=%d\n",
		   cmd, reqtype, value, index, size);

	if (data) {
		buf = kmalloc(size, GFP_KERNEL);
		if (!buf)
			goto out;
	}

	err = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
			      cmd, reqtype, value, index, buf, size,
			      USB_CTRL_GET_TIMEOUT);
	if (err > 0 && err <= size)
		memcpy(data, buf, err);
	kfree(buf);
out:
	return err;
}

Unknown