diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 7452eb31ed1278b96438e1866472bc239407b728..6d9960dd6f35e5ef522c7f9d0d4715d3e3a6365d 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -142,7 +142,7 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
 	/*
 	 * Don't remap the low PCI/ISA area, it's always mapped..
 	 */
-	if (phys_addr >= ISA_START_ADDRESS && last_addr < ISA_END_ADDRESS)
+	if (is_ISA_range(phys_addr, last_addr))
 		return (__force void __iomem *)phys_to_virt(phys_addr);
 
 	/*
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 227df3ca9bfd7523a72a12d0f28b82f106e94d32..5bbc22efe4e53af20c5cf45a8f2879d2a54514a5 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -215,7 +215,7 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
 	}
 
 	/* Low ISA region is always mapped WB in page table. No need to track */
-	if (start >= ISA_START_ADDRESS && (end - 1) <= ISA_END_ADDRESS) {
+	if (is_ISA_range(start, end - 1)) {
 		if (ret_type)
 			*ret_type = _PAGE_CACHE_WB;
 
@@ -415,9 +415,8 @@ int free_memtype(u64 start, u64 end)
 	}
 
 	/* Low ISA region is always mapped WB. No need to track */
-	if (start >= ISA_START_ADDRESS && end <= ISA_END_ADDRESS) {
+	if (is_ISA_range(start, end - 1))
 		return 0;
-	}
 
 	spin_lock(&memtype_lock);
 	list_for_each_entry(ml, &memtype_list, nd) {
diff --git a/include/asm-x86/e820.h b/include/asm-x86/e820.h
index 7004251fc66bd7925a787bd09ccb675dc0714de8..5103d0b2c46ced797cea56b8c37fd9421ead11f6 100644
--- a/include/asm-x86/e820.h
+++ b/include/asm-x86/e820.h
@@ -24,6 +24,7 @@ struct e820map {
 
 #define ISA_START_ADDRESS	0xa0000
 #define ISA_END_ADDRESS		0x100000
+#define is_ISA_range(s, e) ((s) >= ISA_START_ADDRESS && (e) < ISA_END_ADDRESS)
 
 #define BIOS_BEGIN		0x000a0000
 #define BIOS_END		0x00100000