diff --git a/arch/i386/mm/ioremap.c b/arch/i386/mm/ioremap.c
index fff08ae7b5ed..0b278315d737 100644
--- a/arch/i386/mm/ioremap.c
+++ b/arch/i386/mm/ioremap.c
@@ -196,7 +196,7 @@ void iounmap(volatile void __iomem *addr)
 	/* Reset the direct mapping. Can block */
 	if ((p->flags >> 20) && p->phys_addr < virt_to_phys(high_memory) - 1) {
 		change_page_attr(virt_to_page(__va(p->phys_addr)),
-				 p->size >> PAGE_SHIFT,
+				 get_vm_area_size(p) >> PAGE_SHIFT,
 				 PAGE_KERNEL);
 		global_flush_tlb();
 	} 
diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index c2b10cae5da5..89338b468d0d 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -58,6 +58,13 @@ void vmalloc_sync_all(void);
 /*
  *	Lowlevel-APIs (not for driver use!)
  */
+
+static inline size_t get_vm_area_size(const struct vm_struct *area)
+{
+	/* return actual size without guard page */
+	return area->size - PAGE_SIZE;
+}
+
 extern struct vm_struct *get_vm_area(unsigned long size, unsigned long flags);
 extern struct vm_struct *__get_vm_area(unsigned long size, unsigned long flags,
 					unsigned long start, unsigned long end);