diff --git a/mm/compaction.c b/mm/compaction.c
index c62bd06..0d0248d 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -611,8 +611,7 @@
 		continue;
 
 next_pageblock:
-		low_pfn += pageblock_nr_pages;
-		low_pfn = ALIGN(low_pfn, pageblock_nr_pages) - 1;
+		low_pfn = ALIGN(low_pfn + 1, pageblock_nr_pages) - 1;
 		last_pageblock_nr = pageblock_nr;
 	}
 
@@ -795,7 +794,7 @@
 	low_pfn = max(cc->migrate_pfn, zone->zone_start_pfn);
 
 	/* Only scan within a pageblock boundary */
-	end_pfn = ALIGN(low_pfn + pageblock_nr_pages, pageblock_nr_pages);
+	end_pfn = ALIGN(low_pfn + 1, pageblock_nr_pages);
 
 	/* Do not cross the free scanner or scan within a memory hole */
 	if (end_pfn > cc->free_pfn || !pfn_valid(low_pfn)) {