diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 8e333f9..9eadad6 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -229,7 +229,7 @@
 
 	zone_span_writelock(zone);
 
-	old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
+	old_zone_end_pfn = zone_end_pfn(zone);
 	if (!zone->spanned_pages || start_pfn < zone->zone_start_pfn)
 		zone->zone_start_pfn = start_pfn;
 
@@ -514,8 +514,9 @@
 static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,
 			     unsigned long end_pfn)
 {
-	unsigned long zone_start_pfn =  zone->zone_start_pfn;
-	unsigned long zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
+	unsigned long zone_start_pfn = zone->zone_start_pfn;
+	unsigned long z = zone_end_pfn(zone); /* zone_end_pfn namespace clash */
+	unsigned long zone_end_pfn = z;
 	unsigned long pfn;
 	struct mem_section *ms;
 	int nid = zone_to_nid(zone);