mm/page_isolation: use macro to judge the alignment

Signed-off-by: Wang Xiaoqiang <wangxq10@lzu.edu.cn>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Author: Naoya Horiguchi

mm/page_isolation.c

@@ -165,8 +165,8 @@ int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
 	unsigned long undo_pfn;
 	struct page *page;
 
-	BUG_ON((start_pfn) & (pageblock_nr_pages - 1));
-	BUG_ON((end_pfn) & (pageblock_nr_pages - 1));
+	BUG_ON(!IS_ALIGNED(start_pfn, pageblock_nr_pages));
+	BUG_ON(!IS_ALIGNED(end_pfn, pageblock_nr_pages));
 
 	for (pfn = start_pfn;
 	     pfn < end_pfn;