kunit: Add kunit_add_action() to defer a call until test exit

Many uses of the KUnit resource system are intended to simply defer
calling a function until the test exits (be it due to success or
failure). The existing kunit_alloc_resource() function is often used for
this, but was awkward to use (requiring passing NULL init functions, etc),
and returned a resource without incrementing its reference count, which
-- while okay for this use-case -- could cause problems in others.

Instead, introduce a simple kunit_add_action() API: a simple function
(returning nothing, accepting a single void* argument) can be scheduled
to be called when the test exits. Deferred actions are called in the
opposite order to that which they were registered.

This mimics the devres API, devm_add_action(), and also provides
kunit_remove_action(), to cancel a deferred action, and
kunit_release_action() to trigger one early.

This is implemented as a resource under the hood, so the ordering
between resource cleanup and deferred functions is maintained.

Reviewed-by: Benjamin Berg <benjamin.berg@intel.com>
Reviewed-by: Maxime Ripard <maxime@cerno.tech>
Tested-by: Maxime Ripard <maxime@cerno.tech>
Signed-off-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

1 files changed, 87 insertions, 1 deletions

diff --git a/lib/kunit/kunit-test.c b/lib/kunit/kunit-test.c
index 42e44caa1bdd..83d8e90ca7a2 100644
--- a/lib/kunit/kunit-test.c
+++ b/lib/kunit/kunit-test.c
@@ -112,7 +112,7 @@ struct kunit_test_resource_context {
 	struct kunit test;
 	bool is_resource_initialized;
 	int allocate_order[2];
-	int free_order[2];
+	int free_order[4];
 };
 
 static int fake_resource_init(struct kunit_resource *res, void *context)
@@ -403,6 +403,88 @@ static void kunit_resource_test_named(struct kunit *test)
 	KUNIT_EXPECT_TRUE(test, list_empty(&test->resources));
 }
 
+static void increment_int(void *ctx)
+{
+	int *i = (int *)ctx;
+	(*i)++;
+}
+
+static void kunit_resource_test_action(struct kunit *test)
+{
+	int num_actions = 0;
+
+	kunit_add_action(test, increment_int, &num_actions);
+	KUNIT_EXPECT_EQ(test, num_actions, 0);
+	kunit_cleanup(test);
+	KUNIT_EXPECT_EQ(test, num_actions, 1);
+
+	/* Once we've cleaned up, the action queue is empty. */
+	kunit_cleanup(test);
+	KUNIT_EXPECT_EQ(test, num_actions, 1);
+
+	/* Check the same function can be deferred multiple times. */
+	kunit_add_action(test, increment_int, &num_actions);
+	kunit_add_action(test, increment_int, &num_actions);
+	kunit_cleanup(test);
+	KUNIT_EXPECT_EQ(test, num_actions, 3);
+}
+static void kunit_resource_test_remove_action(struct kunit *test)
+{
+	int num_actions = 0;
+
+	kunit_add_action(test, increment_int, &num_actions);
+	KUNIT_EXPECT_EQ(test, num_actions, 0);
+
+	kunit_remove_action(test, increment_int, &num_actions);
+	kunit_cleanup(test);
+	KUNIT_EXPECT_EQ(test, num_actions, 0);
+}
+static void kunit_resource_test_release_action(struct kunit *test)
+{
+	int num_actions = 0;
+
+	kunit_add_action(test, increment_int, &num_actions);
+	KUNIT_EXPECT_EQ(test, num_actions, 0);
+	/* Runs immediately on trigger. */
+	kunit_release_action(test, increment_int, &num_actions);
+	KUNIT_EXPECT_EQ(test, num_actions, 1);
+
+	/* Doesn't run again on test exit. */
+	kunit_cleanup(test);
+	KUNIT_EXPECT_EQ(test, num_actions, 1);
+}
+static void action_order_1(void *ctx)
+{
+	struct kunit_test_resource_context *res_ctx = (struct kunit_test_resource_context *)ctx;
+
+	KUNIT_RESOURCE_TEST_MARK_ORDER(res_ctx, free_order, 1);
+	kunit_log(KERN_INFO, current->kunit_test, "action_order_1");
+}
+static void action_order_2(void *ctx)
+{
+	struct kunit_test_resource_context *res_ctx = (struct kunit_test_resource_context *)ctx;
+
+	KUNIT_RESOURCE_TEST_MARK_ORDER(res_ctx, free_order, 2);
+	kunit_log(KERN_INFO, current->kunit_test, "action_order_2");
+}
+static void kunit_resource_test_action_ordering(struct kunit *test)
+{
+	struct kunit_test_resource_context *ctx = test->priv;
+
+	kunit_add_action(test, action_order_1, ctx);
+	kunit_add_action(test, action_order_2, ctx);
+	kunit_add_action(test, action_order_1, ctx);
+	kunit_add_action(test, action_order_2, ctx);
+	kunit_remove_action(test, action_order_1, ctx);
+	kunit_release_action(test, action_order_2, ctx);
+	kunit_cleanup(test);
+
+	/* [2 is triggered] [2], [(1 is cancelled)] [1] */
+	KUNIT_EXPECT_EQ(test, ctx->free_order[0], 2);
+	KUNIT_EXPECT_EQ(test, ctx->free_order[1], 2);
+	KUNIT_EXPECT_EQ(test, ctx->free_order[2], 1);
+}
+
 static int kunit_resource_test_init(struct kunit *test)
 {
 	struct kunit_test_resource_context *ctx =
@@ -434,6 +516,10 @@ static struct kunit_case kunit_resource_test_cases[] = {
 	KUNIT_CASE(kunit_resource_test_proper_free_ordering),
 	KUNIT_CASE(kunit_resource_test_static),
 	KUNIT_CASE(kunit_resource_test_named),
+	KUNIT_CASE(kunit_resource_test_action),
+	KUNIT_CASE(kunit_resource_test_remove_action),
+	KUNIT_CASE(kunit_resource_test_release_action),
+	KUNIT_CASE(kunit_resource_test_action_ordering),
 	{}
 };