Nouveau - Sep 2017 - [PATCH 4.12 35/43] drm/nouveau: Fix error handling in nv50_disp_atomic_commit

4.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>

commit 813a7e1604eaad1c2792d37d402e1b48b8d0eb3f upstream.

Make it more clear that post commit return ret is really return 0,

and add a missing drm_atomic_helper_cleanup_planes when
drm_atomic_helper_wait_for_fences fails.

Fixes: 839ca903f12e ("drm/nouveau/kms/nv50: transition to atomic interfaces
internally")
Cc: Ben Skeggs <bskeggs at redhat.com>
Cc: dri-devel at lists.freedesktop.org
Cc: nouveau at lists.freedesktop.org
Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Link:
http://patchwork.freedesktop.org/patch/msgid/20170711143314.2148-2-maarten.lankhorst
at linux.intel.com
Reviewed-by: Sean Paul <seanpaul at chromium.org>
[mlankhorst: Use if (ret) to remove the goto in success case.]
Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>

---
 drivers/gpu/drm/nouveau/nv50_display.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

--- a/drivers/gpu/drm/nouveau/nv50_display.c
+++ b/drivers/gpu/drm/nouveau/nv50_display.c
@@ -4091,7 +4091,7 @@ nv50_disp_atomic_commit(struct drm_devic
 	if (!nonblock) {
 		ret = drm_atomic_helper_wait_for_fences(dev, state, true);
 		if (ret)
-			goto done;
+			goto err_cleanup;
 	}
 
 	for_each_plane_in_state(state, plane, plane_state, i) {
@@ -4119,7 +4119,7 @@ nv50_disp_atomic_commit(struct drm_devic
 		if (crtc->state->enable) {
 			if (!drm->have_disp_power_ref) {
 				drm->have_disp_power_ref = true;
-				return ret;
+				return 0;
 			}
 			active = true;
 			break;
@@ -4131,6 +4131,9 @@ nv50_disp_atomic_commit(struct drm_devic
 		drm->have_disp_power_ref = false;
 	}
 
+err_cleanup:
+	if (ret)
+		drm_atomic_helper_cleanup_planes(dev, state);
 done:
 	pm_runtime_put_autosuspend(dev->dev);
 	return ret;