drm_atomic_get_plane_state() allocates a new plane state by
duplicating the current one and inserts it into the atomic commit as
a single operation.

However, a later change will need to insert a plane state into a
commit without going through the full allocation and duplication path
in drm_atomic_get_plane_state().

Extract the state insertion logic into a new static
drm_atomic_commit_set_plane_state() helper, and convert
drm_atomic_get_plane_state() to use it.

Signed-off-by: Maxime Ripard <mripard@kernel.org>
---
 drivers/gpu/drm/drm_atomic.c | 29 +++++++++++++++++++++++------
 1 file changed, 23 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 4ffe5147ab16..56542494ab56 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -624,10 +624,27 @@ static int drm_atomic_connector_check(struct drm_connector *connector,
 	}
 
 	return 0;
 }
 
+static int drm_atomic_commit_set_plane_state(struct drm_atomic_commit *commit,
+					     struct drm_plane *plane,
+					     struct drm_plane_state *plane_state)
+{
+	int index = drm_plane_index(plane);
+
+	drm_modeset_lock_assert_held(&plane->mutex);
+
+	commit->planes[index].state_to_destroy = plane_state;
+	commit->planes[index].old_state = plane->state;
+	commit->planes[index].new_state = plane_state;
+	commit->planes[index].ptr = plane;
+	plane_state->state = commit;
+
+	return 0;
+}
+
 /**
  * drm_atomic_get_plane_state - get plane state
  * @state: global atomic state object
  * @plane: plane to get state object for
  *
@@ -642,11 +659,11 @@ static int drm_atomic_connector_check(struct drm_connector *connector,
  */
 struct drm_plane_state *
 drm_atomic_get_plane_state(struct drm_atomic_commit *state,
 			  struct drm_plane *plane)
 {
-	int ret, index = drm_plane_index(plane);
+	int ret;
 	struct drm_plane_state *plane_state;
 
 	WARN_ON(!state->acquire_ctx);
 	drm_WARN_ON(state->dev, state->checked);
 
@@ -665,15 +682,15 @@ drm_atomic_get_plane_state(struct drm_atomic_commit *state,
 
 	plane_state = plane->funcs->atomic_duplicate_state(plane);
 	if (!plane_state)
 		return ERR_PTR(-ENOMEM);
 
-	state->planes[index].state_to_destroy = plane_state;
-	state->planes[index].ptr = plane;
-	state->planes[index].old_state = plane->state;
-	state->planes[index].new_state = plane_state;
-	plane_state->state = state;
+	ret = drm_atomic_commit_set_plane_state(state, plane, plane_state);
+	if (ret) {
+		plane->funcs->atomic_destroy_state(plane, plane_state);
+		return ERR_PTR(ret);
+	}
 
 	drm_dbg_atomic(plane->dev, "Added [PLANE:%d:%s] %p state to %p\n",
 		       plane->base.id, plane->name, plane_state, state);
 
 	if (plane_state->crtc) {

-- 
2.54.0