[Intel-gfx] [PATCH v4 07/12] drm/i915: GEM operations need to be done under the big lock

[Chris Wilson]

On Tue, Feb 02, 2016 at 02:46:19PM +0000, Tvrtko Ursulin wrote:
> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> 
> VMA creation and GEM list management need the big lock.
> 
> v2:
> 
> Mutex unlock ended on the wrong path somehow. (0-day, Julia Lawall)
> 
> Not to mention drm_gem_object_unreference was there in existing
> code with no mutex held.
> 
> v3:
> 
> Some callers of i915_gem_object_create_stolen_for_preallocated
> already hold the lock so move the mutex into the other caller
> as well.
> 
> v4:
> 
> Changed to lockdep_assert_held. (Chris Wilson)
> 
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>

Also
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
:)

Daniel, what did you think of having a config option to turn
lockdep_assert_held into WARN_ON(!mutex_is_locked()) when lockdep is not
fully-enabled?
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre