drm/atomic: Convert pageflip ioctl locking to interruptible.

Pass DRM_MODESET_ACQUIRE_INTERRUPTIBLE to acquire_init, and handle
drm_modeset_backoff which can now fail by returning the error.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20170912133749.6532-6-maarten.lankhorst@linux.intel.com
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c
index f3a283e2bbd7..5d1c4f452ca8 100644
--- a/drivers/gpu/drm/drm_plane.c
+++ b/drivers/gpu/drm/drm_plane.c
@@ -986,7 +986,7 @@ int drm_mode_page_flip_ioctl(struct drm_device *dev,
                 return -EINVAL;
         }
 
-        drm_modeset_acquire_init(&ctx, 0);
+        drm_modeset_acquire_init(&ctx, DRM_MODESET_ACQUIRE_INTERRUPTIBLE);
 retry:
         ret = drm_modeset_lock(&crtc->mutex, &ctx);
         if (ret)
@@ -1075,8 +1075,9 @@ out:
         crtc->primary->old_fb = NULL;
 
         if (ret == -EDEADLK) {
-                drm_modeset_backoff(&ctx);
-                goto retry;
+                ret = drm_modeset_backoff(&ctx);
+                if (!ret)
+                        goto retry;
         }
 
         drm_modeset_drop_locks(&ctx);