diff --git a/include/linux/mm.h b/include/linux/mm.h
index fa651609b65dbc928a1a3d20035c29b42a1a8947..72a15dc26bbf399bb891f01f740283e723929b33 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -73,7 +73,7 @@ extern unsigned int kobjsize(const void *objp);
 #endif
 
 /*
- * vm_flags..
+ * vm_flags in vm_area_struct, see mm_types.h.
  */
 #define VM_READ		0x00000001	/* currently active flags */
 #define VM_WRITE	0x00000002
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 386edbe2cb4e98b1a01767e15978b02df896d895..bf334138c7c148da4c9ec7b409254045de0d327b 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -113,7 +113,7 @@ struct vm_area_struct {
 	struct vm_area_struct *vm_next;
 
 	pgprot_t vm_page_prot;		/* Access permissions of this VMA. */
-	unsigned long vm_flags;		/* Flags, listed below. */
+	unsigned long vm_flags;		/* Flags, see mm.h. */
 
 	struct rb_node vm_rb;
 
diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index 364789aae9f335c44fa9e8b71848048134ab5ea2..328eb40227277967c8a6179efb56ad14e03fc233 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -4,9 +4,9 @@
 #include <linux/spinlock.h>
 #include <asm/page.h>		/* pgprot_t */
 
-struct vm_area_struct;
+struct vm_area_struct;		/* vma defining user mapping in mm_types.h */
 
-/* bits in vm_struct->flags */
+/* bits in flags of vmalloc's vm_struct below */
 #define VM_IOREMAP	0x00000001	/* ioremap() and friends */
 #define VM_ALLOC	0x00000002	/* vmalloc() */
 #define VM_MAP		0x00000004	/* vmap()ed pages */