[PATCH 07/12] drm/xe/tests: Add helpers to call stubs out of KUnit context

[Lucas De Marchi]

On Fri, Aug 09, 2024 at 06:51:54PM GMT, Michal Wajdeczko wrote:
>The KUNIT_STATIC_STUB_REDIRECT() allows to redirect function call but will
>work only if the caller is in a KUnit context. To allow implementation of
>the more complex test cases, add helpers that allow calling stubs also out
>of a KUnit context.
>
>Signed-off-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
>Cc: Lucas De Marchi <lucas.demarchi at intel.com>
>---
> drivers/gpu/drm/xe/tests/xe_test.h | 74 ++++++++++++++++++++++++++++++
> 1 file changed, 74 insertions(+)
>
>diff --git a/drivers/gpu/drm/xe/tests/xe_test.h b/drivers/gpu/drm/xe/tests/xe_test.h
>index b8fa409ce2b1..ffa8fa6c96f0 100644
>--- a/drivers/gpu/drm/xe/tests/xe_test.h
>+++ b/drivers/gpu/drm/xe/tests/xe_test.h
>@@ -54,11 +54,85 @@ xe_cur_kunit_priv(enum xe_test_priv_id id)
> 	return priv->id == id ? priv : NULL;
> }
>
>+/**
>+ * XE_TEST_REDIRECT() - Call a function stub if one exists.
>+ * @stub: The pointer to the function stub
>+ * @args: All of the arguments passed to this stub
>+ *
>+ * This is a function prologue which is used to allow calls to the current
>+ * function to be redirected if a KUnit is running. If the stub is NULL or
>+ * the KUnit is not running the function will continue execution as normal.
>+ *
>+ * Unlikely the KUNIT_STATIC_STUB_REDIRECT(), this redirection will work
>+ * even if the caller is not in a KUnit context (like a worker thread).
>+ *
>+ * Example:
>+ *
>+ * .. code-block:: c
>+ *
>+ *	int (*stub)(int n);
>+ *
>+ *	int real_func(int n)
>+ *	{
>+ *		XE_TEST_REDIRECT(stub, n);
>+ *		return n + 1;
>+ *	}
>+ *
>+ *	int replacement_func(int n)
>+ *	{
>+ *		return n + 100;
>+ *	}
>+ *
>+ *	void example_test(struct kunit *test)
>+ *	{
>+ *		stub = replacement_func;
>+ *		KUNIT_EXPECT_EQ(test, real_func(1), 101);
>+ *		KUNIT_EXPECT_EQ(test, real_func(1), 101);
>+ *	}
>+ */
>+#define XE_TEST_REDIRECT(stub, args...)							\

this seems another one that should rather be in the kunit layer, not in
xe

>+do {											\
>+	typeof(stub) replacement = (stub);						\
>+	if (XE_TEST_RUNNING()) {							\
>+		if (unlikely(replacement)) {						\
>+			pr_info(KUNIT_SUBTEST_INDENT "# %s: calling stub %ps\n",	\
>+				__func__, replacement);					\

KUNIT_STATIC_STUB_REDIRECT() silently calls the stub without pr_info().
Why does this version need to be extra-verbose?

Lucas De Marchi


>+			return replacement(args);					\
>+		}									\
>+	}										\
>+} while (0)
>+
>+static inline void __nullify_pointer(void *data)
>+{
>+	void **ptr = data;
>+
>+	*ptr = NULL;
>+}
>+
>+/**
>+ * XE_TEST_ACTIVATE_STUB() - Setup a function stub.
>+ * @test: Test case that wants to setup a function stub
>+ * @stub: The function stub pointer
>+ * @replacement: The replacement function
>+ *
>+ * This helper setups a function stub with the replacement function.
>+ * It will also automatically restore stub to NULL at the test end.
>+ */
>+#define XE_TEST_ACTIVATE_STUB(test, stub, replacement)	({					\
>+	typeof(test) __test = (test);								\
>+	typeof(stub) *__ptr = &(stub);								\
>+	typecheck_pointer(*__ptr);								\
>+	*__ptr = (replacement);									\
>+	kunit_info(__test, "activated stub %s with %ps\n", __stringify(stub), *__ptr);		\
>+	kunit_add_action_or_reset(__test, __nullify_pointer, __ptr);				\
>+})
>+
> #else /* if IS_ENABLED(CONFIG_DRM_XE_KUNIT_TEST) */
>
> #define XE_TEST_DECLARE(x)
> #define XE_TEST_ONLY(x) 0
> #define XE_TEST_RUNNING() false
>+#define XE_TEST_REDIRECT(...) do { } while (0)
>
> #define xe_cur_kunit_priv(_id) NULL
>
>-- 
>2.43.0
>