[PATCH v4 1/8] drm/atomic: Avoid connector to writeback_connector casts

[Boris Brezillon]

Use container_of() instead of type casting so that it keeps working
even if base is moved inside the drm_writeback_connector struct.

Signed-off-by: Boris Brezillon <boris.brezillon at bootlin.com>
Reviewed-by: Liviu Dudau <liviu.dudau at arm.com>
Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
Changes in v4:
- None

Changes in v3:
- Add Daniel's and Liviu's R-b

Changes in v2:
- New patch
---
 drivers/gpu/drm/drm_atomic.c | 4 +++-
 include/drm/drm_writeback.h  | 6 ++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index 178842380f75..6ea20d5dee66 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -2423,6 +2423,7 @@ static int prepare_signaling(struct drm_device *dev,
 	}
 
 	for_each_new_connector_in_state(state, conn, conn_state, i) {
+		struct drm_writeback_connector *wb_conn;
 		struct drm_writeback_job *job;
 		struct drm_out_fence_state *f;
 		struct dma_fence *fence;
@@ -2446,7 +2447,8 @@ static int prepare_signaling(struct drm_device *dev,
 		f[*num_fences].out_fence_ptr = fence_ptr;
 		*fence_state = f;
 
-		fence = drm_writeback_get_out_fence((struct drm_writeback_connector *)conn);
+		wb_conn = drm_connector_to_writeback(conn);
+		fence = drm_writeback_get_out_fence(wb_conn);
 		if (!fence)
 			return -ENOMEM;
 
diff --git a/include/drm/drm_writeback.h b/include/drm/drm_writeback.h
index a10fe556dfd4..23df9d463003 100644
--- a/include/drm/drm_writeback.h
+++ b/include/drm/drm_writeback.h
@@ -110,6 +110,12 @@ struct drm_writeback_job {
 	struct dma_fence *out_fence;
 };
 
+static inline struct drm_writeback_connector *
+drm_connector_to_writeback(struct drm_connector *connector)
+{
+	return container_of(connector, struct drm_writeback_connector, base);
+}
+
 int drm_writeback_connector_init(struct drm_device *dev,
 				 struct drm_writeback_connector *wb_connector,
 				 const struct drm_connector_funcs *con_funcs,
-- 
2.14.1