[PATCH] drm/amd/display: Only put primary planes into the mode_info->planes list

[Nicholas Kazlauskas]

We want DRM planes to be initialized in the following order:

- primary planes
- overlay planes
- cursor planes

to support existing userspace expectations for plane z-ordering. This
means that we also need to register CRTCs after all planes have been
initialized since overlay planes can be placed on any CRTC.

So the only reason why we have the mode_info->planes list is to
remember the primary planes for use later when we need to register
the CRTC.

Overlay planes have no purpose being in this list. DRM will cleanup
any planes that we've registered for us, so the only planes that need to
be explicitly cleaned up are the ones that have failed to register.

By dropping the explicit free on every plane in the mode_info->planes
list this patch also fixes a double-free in the case where we fail to
initialize only some of the planes.

Cc: Leo Li <sunpeng.li at amd.com>
Cc: Harry Wentland <harry.wentland at amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas at amd.com>
---
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index cde0da3ae964..f770de36121f 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -1818,8 +1818,6 @@ static int initialize_plane(struct amdgpu_display_manager *dm,
 	int ret = 0;
 
 	plane = kzalloc(sizeof(struct drm_plane), GFP_KERNEL);
-	mode_info->planes[plane_id] = plane;
-
 	if (!plane) {
 		DRM_ERROR("KMS: Failed to allocate plane\n");
 		return -ENOMEM;
@@ -1836,13 +1834,17 @@ static int initialize_plane(struct amdgpu_display_manager *dm,
 	if (plane_id >= dm->dc->caps.max_streams)
 		possible_crtcs = 0xff;
 
-	ret = amdgpu_dm_plane_init(dm, mode_info->planes[plane_id], possible_crtcs);
+	ret = amdgpu_dm_plane_init(dm, plane, possible_crtcs);
 
 	if (ret) {
 		DRM_ERROR("KMS: Failed to initialize plane\n");
+		kfree(plane);
 		return ret;
 	}
 
+	if (mode_info)
+		mode_info->planes[plane_id] = plane;
+
 	return ret;
 }
 
@@ -1885,7 +1887,7 @@ static int amdgpu_dm_initialize_drm_device(struct amdgpu_device *adev)
 	struct amdgpu_encoder *aencoder = NULL;
 	struct amdgpu_mode_info *mode_info = &adev->mode_info;
 	uint32_t link_cnt;
-	int32_t overlay_planes, primary_planes, total_planes;
+	int32_t overlay_planes, primary_planes;
 	enum dc_connection_type new_connection_type = dc_connection_none;
 
 	link_cnt = dm->dc->caps.max_links;
@@ -1914,9 +1916,7 @@ static int amdgpu_dm_initialize_drm_device(struct amdgpu_device *adev)
 
 	/* There is one primary plane per CRTC */
 	primary_planes = dm->dc->caps.max_streams;
-
-	total_planes = primary_planes + overlay_planes;
-	ASSERT(total_planes <= AMDGPU_MAX_PLANES);
+	ASSERT(primary_planes <= AMDGPU_MAX_PLANES);
 
 	/*
 	 * Initialize primary planes, implicit planes for legacy IOCTLS.
@@ -1937,7 +1937,7 @@ static int amdgpu_dm_initialize_drm_device(struct amdgpu_device *adev)
 	 * Order is reversed to match iteration order in atomic check.
 	 */
 	for (i = (overlay_planes - 1); i >= 0; i--) {
-		if (initialize_plane(dm, mode_info, primary_planes + i,
+		if (initialize_plane(dm, NULL, primary_planes + i,
 				     DRM_PLANE_TYPE_OVERLAY)) {
 			DRM_ERROR("KMS: Failed to initialize overlay plane\n");
 			goto fail;
@@ -2041,8 +2041,7 @@ static int amdgpu_dm_initialize_drm_device(struct amdgpu_device *adev)
 fail:
 	kfree(aencoder);
 	kfree(aconnector);
-	for (i = 0; i < primary_planes; i++)
-		kfree(mode_info->planes[i]);
+
 	return -EINVAL;
 }
 
-- 
2.17.1