missing atomic_read_long() in slub.c

nr_slabs is atomic_long_t, not atomic_t
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/slub.c

@@ -2734,7 +2734,7 @@ static void slab_mem_offline_callback(void *arg)
 			 * and offline_pages() function shoudn't call this
 			 * callback. So, we must fail.
 			 */
-			BUG_ON(atomic_read(&n->nr_slabs));
+			BUG_ON(atomic_long_read(&n->nr_slabs));
 
 			s->node[offline_node] = NULL;
 			kmem_cache_free(kmalloc_caches, n);