diff --git a/include/linux/drbd_limits.h b/include/linux/drbd_limits.h
index cd3565cfed4413aecc78da313e7b386b19f5344c..7d956e91ae7be8081d9f7b8bbce6bc012a5563e9 100644
--- a/include/linux/drbd_limits.h
+++ b/include/linux/drbd_limits.h
@@ -137,7 +137,7 @@
 #define DRBD_AL_EXTENTS_SCALE '1'
 
 #define DRBD_MINOR_NUMBER_MIN  -1
-#define DRBD_MINOR_NUMBER_MAX  (1<<30)
+#define DRBD_MINOR_NUMBER_MAX  ((1 << 20) - 1)
 #define DRBD_MINOR_NUMBER_DEF  -1
 #define DRBD_MINOR_NUMBER_SCALE '1'