diff options
Diffstat (limited to 'drivers/gpu/drm/msm/msm_gem.h')
| -rw-r--r-- | drivers/gpu/drm/msm/msm_gem.h | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/drivers/gpu/drm/msm/msm_gem.h b/drivers/gpu/drm/msm/msm_gem.h index d608339c1643..432032ad4aed 100644 --- a/drivers/gpu/drm/msm/msm_gem.h +++ b/drivers/gpu/drm/msm/msm_gem.h @@ -229,7 +229,19 @@ msm_gem_unlock(struct drm_gem_object *obj) static inline bool msm_gem_is_locked(struct drm_gem_object *obj) { - return dma_resv_is_locked(obj->resv); + /* + * Destroying the object is a special case.. msm_gem_free_object() + * calls many things that WARN_ON if the obj lock is not held. But + * acquiring the obj lock in msm_gem_free_object() can cause a + * locking order inversion between reservation_ww_class_mutex and + * fs_reclaim. + * + * This deadlock is not actually possible, because no one should + * be already holding the lock when msm_gem_free_object() is called. + * Unfortunately lockdep is not aware of this detail. So when the + * refcount drops to zero, we pretend it is already locked. + */ + return dma_resv_is_locked(obj->resv) || (kref_read(&obj->refcount) == 0); } static inline bool is_active(struct msm_gem_object *msm_obj) |