diff --git a/mm/internal.h b/mm/internal.h
index 7aa2ea0a8623..bfad3b5d2665 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -133,9 +133,9 @@ struct alloc_context {
  * Assumption: *_mem_map is contiguous at least up to MAX_ORDER
  */
 static inline unsigned long
-__find_buddy_index(unsigned long page_idx, unsigned int order)
+__find_buddy_pfn(unsigned long page_pfn, unsigned int order)
 {
-	return page_idx ^ (1 << order);
+	return page_pfn ^ (1 << order);
 }
 
 extern struct page *__pageblock_pfn_to_page(unsigned long start_pfn,
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 3c790ae4cb52..49d40261f8c4 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -787,9 +787,8 @@ static inline void __free_one_page(struct page *page,
 		struct zone *zone, unsigned int order,
 		int migratetype)
 {
-	unsigned long page_idx;
-	unsigned long combined_idx;
-	unsigned long uninitialized_var(buddy_idx);
+	unsigned long combined_pfn;
+	unsigned long uninitialized_var(buddy_pfn);
 	struct page *buddy;
 	unsigned int max_order;
 
@@ -802,15 +801,13 @@ static inline void __free_one_page(struct page *page,
 	if (likely(!is_migrate_isolate(migratetype)))
 		__mod_zone_freepage_state(zone, 1 << order, migratetype);
 
-	page_idx = pfn & ((1 << MAX_ORDER) - 1);
-
-	VM_BUG_ON_PAGE(page_idx & ((1 << order) - 1), page);
+	VM_BUG_ON_PAGE(pfn & ((1 << order) - 1), page);
 	VM_BUG_ON_PAGE(bad_range(zone, page), page);
 
 continue_merging:
 	while (order < max_order - 1) {
-		buddy_idx = __find_buddy_index(page_idx, order);
-		buddy = page + (buddy_idx - page_idx);
+		buddy_pfn = __find_buddy_pfn(pfn, order);
+		buddy = page + (buddy_pfn - pfn);
 		if (!page_is_buddy(page, buddy, order))
 			goto done_merging;
 		/*
@@ -824,9 +821,9 @@ continue_merging:
 			zone->free_area[order].nr_free--;
 			rmv_page_order(buddy);
 		}
-		combined_idx = buddy_idx & page_idx;
-		page = page + (combined_idx - page_idx);
-		page_idx = combined_idx;
+		combined_pfn = buddy_pfn & pfn;
+		page = page + (combined_pfn - pfn);
+		pfn = combined_pfn;
 		order++;
 	}
 	if (max_order < MAX_ORDER) {
@@ -841,8 +838,8 @@ continue_merging:
 		if (unlikely(has_isolate_pageblock(zone))) {
 			int buddy_mt;
 
-			buddy_idx = __find_buddy_index(page_idx, order);
-			buddy = page + (buddy_idx - page_idx);
+			buddy_pfn = __find_buddy_pfn(pfn, order);
+			buddy = page + (buddy_pfn - pfn);
 			buddy_mt = get_pageblock_migratetype(buddy);
 
 			if (migratetype != buddy_mt
@@ -867,10 +864,10 @@ done_merging:
 	 */
 	if ((order < MAX_ORDER-2) && pfn_valid_within(page_to_pfn(buddy))) {
 		struct page *higher_page, *higher_buddy;
-		combined_idx = buddy_idx & page_idx;
-		higher_page = page + (combined_idx - page_idx);
-		buddy_idx = __find_buddy_index(combined_idx, order + 1);
-		higher_buddy = higher_page + (buddy_idx - combined_idx);
+		combined_pfn = buddy_pfn & pfn;
+		higher_page = page + (combined_pfn - pfn);
+		buddy_pfn = __find_buddy_pfn(combined_pfn, order + 1);
+		higher_buddy = higher_page + (buddy_pfn - combined_pfn);
 		if (page_is_buddy(higher_page, higher_buddy, order + 1)) {
 			list_add_tail(&page->lru,
 				&zone->free_area[order].free_list[migratetype]);
diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index a5594bfcc5ed..dadb7e74d7d6 100644
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -83,7 +83,7 @@ static void unset_migratetype_isolate(struct page *page, unsigned migratetype)
 	unsigned long flags, nr_pages;
 	bool isolated_page = false;
 	unsigned int order;
-	unsigned long page_idx, buddy_idx;
+	unsigned long pfn, buddy_pfn;
 	struct page *buddy;
 
 	zone = page_zone(page);
@@ -102,9 +102,9 @@ static void unset_migratetype_isolate(struct page *page, unsigned migratetype)
 	if (PageBuddy(page)) {
 		order = page_order(page);
 		if (order >= pageblock_order) {
-			page_idx = page_to_pfn(page) & ((1 << MAX_ORDER) - 1);
-			buddy_idx = __find_buddy_index(page_idx, order);
-			buddy = page + (buddy_idx - page_idx);
+			pfn = page_to_pfn(page);
+			buddy_pfn = __find_buddy_pfn(pfn, order);
+			buddy = page + (buddy_pfn - pfn);
 
 			if (pfn_valid_within(page_to_pfn(buddy)) &&
 			    !is_migrate_isolate_page(buddy)) {