ignore redirection loop from mobile device to full website

I use this code to redirect users to mobile site :
Dim userAgent As String = Request.UserAgent.ToString().ToLower() If userAgent IsNot Nothing Then If Request.Browser.IsMobileDevice = True Then Response.Redirect("http://m.domain.com") End If End If and I put full web site link back in mobile site if any user want to see full version website from mobile ,how can I prevent redirect loop for mobile users with this link ?