We reserve space in the GuC workqueue for submitting the request in the future. However, if we fail to construct the request, we need to give that reserved space back to the system. Fixes:dadd481bfe("drm/i915/guc: Prepare for nonblocking execbuf submission") Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97978 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Michał Winiarski <michal.winiarski@intel.com> Reviewed-by: Michał Winiarski <michal.winiarski@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/20161007065327.24515-4-chris@chris-wilson.co.uk (cherry picked from commit5ba899082c) Signed-off-by: Jani Nikula <jani.nikula@intel.com>