drm/tests: helpers: Create a helper to allocate a locking ctx

As we get more and more tests, the locking context initialisation
creates more and more boilerplate, both at creation and destruction.

Let's create a helper that will allocate, initialise a context, and
register kunit actions to clean up once the test is done.
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Maíra Canal <mairacanal@riseup.net>
Link: https://lore.kernel.org/r/20230728-kms-kunit-actions-rework-v3-5-952565ccccfe@kernel.orgSigned-off-by: Maxime Ripard <mripard@kernel.org>

drivers/gpu/drm/tests/drm_kunit_helpers.c

@@ -146,5 +146,46 @@ __drm_kunit_helper_alloc_drm_device_with_driver(struct kunit *test,
 }
 EXPORT_SYMBOL_GPL(__drm_kunit_helper_alloc_drm_device_with_driver);
 
+static void action_drm_release_context(void *ptr)
+{
+	struct drm_modeset_acquire_ctx *ctx = ptr;
+
+	drm_modeset_drop_locks(ctx);
+	drm_modeset_acquire_fini(ctx);
+}
+
+/**
+ * drm_kunit_helper_context_alloc - Allocates an acquire context
+ * @test: The test context object
+ *
+ * Allocates and initializes a modeset acquire context.
+ *
+ * The context is tied to the kunit test context, so we must not call
+ * drm_modeset_acquire_fini() on it, it will be done so automatically.
+ *
+ * Returns:
+ * An ERR_PTR on error, a pointer to the newly allocated context otherwise
+ */
+struct drm_modeset_acquire_ctx *
+drm_kunit_helper_acquire_ctx_alloc(struct kunit *test)
+{
+	struct drm_modeset_acquire_ctx *ctx;
+	int ret;
+
+	ctx = kunit_kzalloc(test, sizeof(*ctx), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, ctx);
+
+	drm_modeset_acquire_init(ctx, 0);
+
+	ret = kunit_add_action_or_reset(test,
+					action_drm_release_context,
+					ctx);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return ctx;
+}
+EXPORT_SYMBOL_GPL(drm_kunit_helper_acquire_ctx_alloc);
+
 MODULE_AUTHOR("Maxime Ripard <maxime@cerno.tech>");
 MODULE_LICENSE("GPL");

include/drm/drm_kunit_helpers.h

@@ -87,5 +87,7 @@ __drm_kunit_helper_alloc_drm_device(struct kunit *test,
 						      sizeof(_type),		\
 						      offsetof(_type, _member),	\
 						      _feat))
+struct drm_modeset_acquire_ctx *
+drm_kunit_helper_acquire_ctx_alloc(struct kunit *test);
 
 #endif // DRM_KUNIT_HELPERS_H_