Non-blocking commits on -ERESTARTSYS

[Leo Li]

Hi Daniel, Maarten,

Just digging an old thread out of the grave:
https://lists.freedesktop.org/archives/dri-devel/2017-August/150495.html

It's suppose to fix a memory leak on the drm_commit object during
non-blocking commits. Within drm_atomic_helper_setup_commit, a reference
to the commit object is obtained by the new_crtc_state. This reference
is suppose to be 'put' once flip_done is signaled (via the
release_crtc_commit callback), but never happens if .prepare_fb returns
-ERESTARTSYS: drm_atomic_helper_commit early returns before the
commit_tail work is queued.

We're starting to bump into this issue again. Regarding Daniel's
suggestion for an IGT test, has there been any work done on it? I'd be
interested in taking a look otherwise. As a side note, I can also
reproduce this on i915.

Thanks,
Leo