diff --git a/lib/lcm.c b/lib/lcm.c
index e97dbd5..03d7fcb 100644
--- a/lib/lcm.c
+++ b/lib/lcm.c
@@ -12,3 +12,14 @@
 		return 0;
 }
 EXPORT_SYMBOL_GPL(lcm);
+
+unsigned long lcm_not_zero(unsigned long a, unsigned long b)
+{
+	unsigned long l = lcm(a, b);
+
+	if (l)
+		return l;
+
+	return (b ? : a);
+}
+EXPORT_SYMBOL_GPL(lcm_not_zero);