As Maxime suggested, add a new helper
drm_kunit_display_mode_from_cea_vic(), it can replace the direct call
of drm_display_mode_from_cea_vic(), and it will help solving
the `mode` memory leaks.

Acked-by: Maxime Ripard <mripard@kernel.org>
Suggested-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
---
v4:
- Return NULL early if drm_display_mode_from_cea_vic() return NULL,
  because it doesn't really make much sense to register a cleanup action
  if we know that it's going to be useless.
v3:
- Adjust drm/drm_edid.h header to drm_kunit_helpers.c.
- Drop the "helper" in the helper name.
- Add Acked-by.
---
 drivers/gpu/drm/tests/drm_kunit_helpers.c | 42 +++++++++++++++++++++++
 include/drm/drm_kunit_helpers.h           |  4 +++
 2 files changed, 46 insertions(+)

diff --git a/drivers/gpu/drm/tests/drm_kunit_helpers.c b/drivers/gpu/drm/tests/drm_kunit_helpers.c
index aa62719dab0e..04a6b8cc62ac 100644
--- a/drivers/gpu/drm/tests/drm_kunit_helpers.c
+++ b/drivers/gpu/drm/tests/drm_kunit_helpers.c
@@ -3,6 +3,7 @@
 #include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_drv.h>
+#include <drm/drm_edid.h>
 #include <drm/drm_fourcc.h>
 #include <drm/drm_kunit_helpers.h>
 #include <drm/drm_managed.h>
@@ -311,6 +312,47 @@ drm_kunit_helper_create_crtc(struct kunit *test,
 }
 EXPORT_SYMBOL_GPL(drm_kunit_helper_create_crtc);
 
+static void kunit_action_drm_mode_destroy(void *ptr)
+{
+	struct drm_display_mode *mode = ptr;
+
+	drm_mode_destroy(NULL, mode);
+}
+
+/**
+ * drm_kunit_display_mode_from_cea_vic() - return a mode for CEA VIC
+					   for a KUnit test
+ * @test: The test context object
+ * @dev: DRM device
+ * @video_code: CEA VIC of the mode
+ *
+ * Creates a new mode matching the specified CEA VIC for a KUnit test.
+ *
+ * Resources will be cleaned up automatically.
+ *
+ * Returns: A new drm_display_mode on success or NULL on failure
+ */
+struct drm_display_mode *
+drm_kunit_display_mode_from_cea_vic(struct kunit *test, struct drm_device *dev,
+				    u8 video_code)
+{
+	struct drm_display_mode *mode;
+	int ret;
+
+	mode = drm_display_mode_from_cea_vic(dev, video_code);
+	if (!mode)
+		return NULL;
+
+	ret = kunit_add_action_or_reset(test,
+					kunit_action_drm_mode_destroy,
+					mode);
+	if (ret)
+		return NULL;
+
+	return mode;
+}
+EXPORT_SYMBOL_GPL(drm_kunit_display_mode_from_cea_vic);
+
 MODULE_AUTHOR("Maxime Ripard <maxime@cerno.tech>");
 MODULE_DESCRIPTION("KUnit test suite helper functions");
 MODULE_LICENSE("GPL");
diff --git a/include/drm/drm_kunit_helpers.h b/include/drm/drm_kunit_helpers.h
index e7cc17ee4934..afdd46ef04f7 100644
--- a/include/drm/drm_kunit_helpers.h
+++ b/include/drm/drm_kunit_helpers.h
@@ -120,4 +120,8 @@ drm_kunit_helper_create_crtc(struct kunit *test,
 			     const struct drm_crtc_funcs *funcs,
 			     const struct drm_crtc_helper_funcs *helper_funcs);
 
+struct drm_display_mode *
+drm_kunit_display_mode_from_cea_vic(struct kunit *test, struct drm_device *dev,
+				    u8 video_code);
+
 #endif // DRM_KUNIT_HELPERS_H_
-- 
2.34.1