drm/tests: helpers: Create a helper to allocate an atomic state

As we gain more tests, boilerplate to allocate an atomic state and free
it starts to be there more and more as well.

In order to reduce the allocation boilerplate, we can create a helper
to create that atomic state, and call an action when the test is done.
This will also clean up the exit path.
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-v3-6-952565ccccfe@kernel.orgSigned-off-by: Maxime Ripard <mripard@kernel.org>

drivers/gpu/drm/tests/drm_kunit_helpers.c

 // SPDX-License-Identifier: GPL-2.0
 
+#include <drm/drm_atomic.h>
 #include <drm/drm_drv.h>
 #include <drm/drm_kunit_helpers.h>
 #include <drm/drm_managed.h>
@@ -187,5 +188,50 @@ drm_kunit_helper_acquire_ctx_alloc(struct kunit *test)
 }
 EXPORT_SYMBOL_GPL(drm_kunit_helper_acquire_ctx_alloc);
 
+static void kunit_action_drm_atomic_state_put(void *ptr)
+{
+	struct drm_atomic_state *state = ptr;
+
+	drm_atomic_state_put(state);
+}
+
+/**
+ * drm_kunit_helper_atomic_state_alloc - Allocates an atomic state
+ * @test: The test context object
+ * @drm: The device to alloc the state for
+ * @ctx: Locking context for that atomic update
+ *
+ * Allocates a empty atomic state.
+ *
+ * The state is tied to the kunit test context, so we must not call
+ * drm_atomic_state_put() on it, it will be done so automatically.
+ *
+ * Returns:
+ * An ERR_PTR on error, a pointer to the newly allocated state otherwise
+ */
+struct drm_atomic_state *
+drm_kunit_helper_atomic_state_alloc(struct kunit *test,
+				    struct drm_device *drm,
+				    struct drm_modeset_acquire_ctx *ctx)
+{
+	struct drm_atomic_state *state;
+	int ret;
+
+	state = drm_atomic_state_alloc(drm);
+	if (!state)
+		return ERR_PTR(-ENOMEM);
+
+	ret = kunit_add_action_or_reset(test,
+					kunit_action_drm_atomic_state_put,
+					state);
+	if (ret)
+		return ERR_PTR(ret);
+
+	state->acquire_ctx = ctx;
+
+	return state;
+}
+EXPORT_SYMBOL_GPL(drm_kunit_helper_atomic_state_alloc);
+
 MODULE_AUTHOR("Maxime Ripard <maxime@cerno.tech>");
 MODULE_LICENSE("GPL");

include/drm/drm_kunit_helpers.h

@@ -90,4 +90,9 @@ __drm_kunit_helper_alloc_drm_device(struct kunit *test,
 struct drm_modeset_acquire_ctx *
 drm_kunit_helper_acquire_ctx_alloc(struct kunit *test);
 
+struct drm_atomic_state *
+drm_kunit_helper_atomic_state_alloc(struct kunit *test,
+				    struct drm_device *drm,
+				    struct drm_modeset_acquire_ctx *ctx);
+
 #endif // DRM_KUNIT_HELPERS_H_