xarray: Move multiorder account test in-kernel

Move this test to the in-kernel test suite, and enhance it to test
several different orders.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
diff --git a/lib/test_xarray.c b/lib/test_xarray.c
index ca86141..38cab4c 100644
--- a/lib/test_xarray.c
+++ b/lib/test_xarray.c
@@ -1019,6 +1019,37 @@
 	XA_BUG_ON(xa, !xa_empty(xa));
 }
 
+/*
+ * Check that the pointer / value / sibling entries are accounted the
+ * way we expect them to be.
+ */
+static noinline void check_account(struct xarray *xa)
+{
+#ifdef CONFIG_XARRAY_MULTI
+	unsigned int order;
+
+	for (order = 1; order < 12; order++) {
+		XA_STATE(xas, xa, 1 << order);
+
+		xa_store_order(xa, 0, order, xa, GFP_KERNEL);
+		xas_load(&xas);
+		XA_BUG_ON(xa, xas.xa_node->count == 0);
+		XA_BUG_ON(xa, xas.xa_node->count > (1 << order));
+		XA_BUG_ON(xa, xas.xa_node->nr_values != 0);
+
+		xa_store_order(xa, 1 << order, order, xa_mk_value(1 << order),
+				GFP_KERNEL);
+		XA_BUG_ON(xa, xas.xa_node->count != xas.xa_node->nr_values * 2);
+
+		xa_erase(xa, 1 << order);
+		XA_BUG_ON(xa, xas.xa_node->nr_values != 0);
+
+		xa_erase(xa, 0);
+		XA_BUG_ON(xa, !xa_empty(xa));
+	}
+#endif
+}
+
 static noinline void check_destroy(struct xarray *xa)
 {
 	unsigned long index;
@@ -1068,6 +1099,7 @@
 	check_xa_alloc();
 	check_find(&array);
 	check_find_entry(&array);
+	check_account(&array);
 	check_destroy(&array);
 	check_move(&array);
 	check_create_range(&array);