diff --git a/arch/sh/include/asm/pgtable.h b/arch/sh/include/asm/pgtable.h
index 083ea068e819..db85916b9e95 100644
--- a/arch/sh/include/asm/pgtable.h
+++ b/arch/sh/include/asm/pgtable.h
@@ -134,6 +134,7 @@ typedef pte_t *pte_addr_t;
 extern void pgtable_cache_init(void);
 
 struct vm_area_struct;
+struct mm_struct;
 
 extern void __update_cache(struct vm_area_struct *vma,
 			   unsigned long address, pte_t pte);