diff --git a/mm/sparse.c b/mm/sparse.c
index db6bf3c..6903c8f 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -248,10 +248,7 @@ static int __meminit sparse_init_one_section(struct mem_section *ms,
 
 unsigned long usemap_size(void)
 {
-	unsigned long size_bytes;
-	size_bytes = roundup(SECTION_BLOCKFLAGS_BITS, 8) / 8;
-	size_bytes = roundup(size_bytes, sizeof(unsigned long));
-	return size_bytes;
+	return BITS_TO_LONGS(SECTION_BLOCKFLAGS_BITS) * sizeof(unsigned long);
 }
 
 #ifdef CONFIG_MEMORY_HOTPLUG