mm: check PageUnevictable in lru_deactivate_fn()

The lru_deactivate_fn should not move page which in on unevictable lru
into inactive list.  Otherwise, we can meet BUG when we use
isolate_lru_pages as __isolate_lru_page could return -EINVAL.
Reported-by: NYing Han <yinghan@google.com>
Tested-by: NYing Han <yinghan@google.com>
Signed-off-by: NMinchan Kim <minchan.kim@gmail.com>
Reviewed-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Rik van Riel<riel@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/swap.c

@@ -396,6 +396,9 @@ static void lru_deactivate_fn(struct page *page, void *arg)
 	if (!PageLRU(page))
 		return;
 
+	if (PageUnevictable(page))
+		return;
+
 	/* Some processes are using the page */
 	if (page_mapped(page))
 		return;