diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index 31e8041274f6..f74856e17e48 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -34,6 +34,7 @@ struct vm_area_struct;
 #define ___GFP_NO_KSWAPD	0x400000u
 #define ___GFP_OTHER_NODE	0x800000u
 #define ___GFP_WRITE		0x1000000u
+/* If the above are modified, __GFP_BITS_SHIFT may need updating */
 
 /*
  * GFP bitmasks..