slub: fix atomic usage in any_slab_objects()

any_slab_objects() does an atomic_read on an atomic_long_t, this
fixes it to use atomic_long_read instead.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/slub.c

@@ -3762,7 +3762,7 @@ static int any_slab_objects(struct kmem_cache *s)
 		if (!n)
 			continue;
 
-		if (atomic_read(&n->total_objects))
+		if (atomic_long_read(&n->total_objects))
 			return 1;
 	}
 	return 0;