[PATCH v3 2/2] test_maple_tree: test maple_range_64 node in RCU mode

[Dimitris Charisis]

This commit adds a test that builds two maple_range_64 trees in RCU
mode.  The first tree has a root that is a full maple_range_64 node and
ensures that the destruction under RCU does not misinterpret the last
slot as metadata. 226 insertions produce such a root on a 64-bit build.

The second tree is a height 3 tree whose root holds 15 child pointers
and metadata in its last slot, so every slot is non-zero and ensures
that the destruction under RCU does not descend into the metadata slot.
3166 insertions produce such a tree on a 64-bit build.

Signed-off-by: Dimitris Charisis <dchar@xxxxxxxxxxxxxxxxx>
---
 lib/test_maple_tree.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/lib/test_maple_tree.c b/lib/test_maple_tree.c
index b9367c61e8b50d107ab972fc5222fb6a531fad87..fb40e193a3cb76f0eb02af3aa4a38630692a4a9b 100644
--- a/lib/test_maple_tree.c
+++ b/lib/test_maple_tree.c
@@ -3710,6 +3710,36 @@ static noinline void __init alloc_cyclic_testing(struct maple_tree *mt)
 	MT_BUG_ON(mt, ret != 1);
 }
 
+static noinline void __init check_range64_in_rcu(struct maple_tree *mt)
+{
+	unsigned long i;
+	unsigned long nr_entries = 226; /* Build a full maple_range_64 root node */
+
+	MT_BUG_ON(mt, !mtree_empty(mt));
+	mt_init_flags(mt, MT_FLAGS_USE_RCU);
+
+	for (i = 0; i < nr_entries; i++) {
+		MT_BUG_ON(mt, mtree_test_insert_range(mt, i*10, i*10 + 9,
+						      xa_mk_value(i)));
+	}
+
+	mtree_destroy(mt);
+	rcu_barrier();
+
+	nr_entries = 3166; /* Height 3. Root has 15 children + metadata */
+
+	MT_BUG_ON(mt, !mtree_empty(mt));
+	mt_init_flags(mt, MT_FLAGS_USE_RCU);
+
+	for (i = 0; i < nr_entries; i++) {
+		MT_BUG_ON(mt, mtree_test_insert_range(mt, i*10, i*10 + 9,
+						      xa_mk_value(i)));
+	}
+
+	mtree_destroy(mt);
+	rcu_barrier();
+}
+
 static DEFINE_MTREE(tree);
 static int __init maple_tree_seed(void)
 {
@@ -3999,6 +4029,8 @@ static int __init maple_tree_seed(void)
 	alloc_cyclic_testing(&tree);
 	mtree_destroy(&tree);
 
+	check_range64_in_rcu(&tree);
+
 
 #if defined(BENCH)
 skip:

-- 
2.47.3