[PATCH 21/26] drm: use new iterator in drm_gem_plane_helper_prepare_fb v2

["Christian König" <ckoenig.leichtzumerken@gmail.com>]

Makes the handling a bit more complex, but avoids the use of
dma_resv_get_excl_unlocked().

v2: add missing rcu_read_lock()/unlock()

Signed-off-by: Christian König <christian.koenig@amd.com>
---
 drivers/gpu/drm/drm_gem_atomic_helper.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_gem_atomic_helper.c b/drivers/gpu/drm/drm_gem_atomic_helper.c
index e570398abd78..d8f9c6432544 100644
--- a/drivers/gpu/drm/drm_gem_atomic_helper.c
+++ b/drivers/gpu/drm/drm_gem_atomic_helper.c
@@ -143,6 +143,7 @@
  */
 int drm_gem_plane_helper_prepare_fb(struct drm_plane *plane, struct drm_plane_state *state)
 {
+	struct dma_resv_iter cursor;
 	struct drm_gem_object *obj;
 	struct dma_fence *fence;
 
@@ -150,9 +151,18 @@ int drm_gem_plane_helper_prepare_fb(struct drm_plane *plane, struct drm_plane_st
 		return 0;
 
 	obj = drm_gem_fb_get_obj(state->fb, 0);
-	fence = dma_resv_get_excl_unlocked(obj->resv);
-	drm_atomic_set_fence_for_plane(state, fence);
+	rcu_read_lock();
+	dma_resv_iter_begin(&cursor, obj->resv, false);
+	dma_resv_for_each_fence_unlocked(&cursor, fence) {
+		rcu_read_unlock();
+		/* TODO: We only use the first write fence here */
+		drm_atomic_set_fence_for_plane(state, fence);
+		return 0;
+	}
+	dma_resv_iter_end(&cursor);
+	rcu_read_unlock();
 
+	drm_atomic_set_fence_for_plane(state, NULL);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(drm_gem_plane_helper_prepare_fb);
-- 
2.25.1