In a future patch, _drm_lease_held will dereference drm_file->master only after making a call to drm_file_get_master. This will increment the reference count of drm_file->master while holding onto a new drm_file.master_lock.
In preparation for this, the call to _drm_lease_held should be moved out from the section locked by &dev->mode_config.idr_mutex. This avoids creating new lock hierarchies between &dev->mode_config.idr_mutex and &drm_file->master_lock.
Reported-by: Daniel Vetter daniel.vetter@ffwll.ch Signed-off-by: Desmond Cheong Zhi Xi desmondcheongzx@gmail.com --- drivers/gpu/drm/drm_mode_object.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/drm_mode_object.c b/drivers/gpu/drm/drm_mode_object.c index b26588b52795..83e35ff3b13a 100644 --- a/drivers/gpu/drm/drm_mode_object.c +++ b/drivers/gpu/drm/drm_mode_object.c @@ -146,16 +146,18 @@ struct drm_mode_object *__drm_mode_object_find(struct drm_device *dev, if (obj && obj->id != id) obj = NULL;
- if (obj && drm_mode_object_lease_required(obj->type) && - !_drm_lease_held(file_priv, obj->id)) - obj = NULL; - if (obj && obj->free_cb) { if (!kref_get_unless_zero(&obj->refcount)) obj = NULL; } mutex_unlock(&dev->mode_config.idr_mutex);
+ if (obj && drm_mode_object_lease_required(obj->type) && + !_drm_lease_held(file_priv, obj->id)) { + drm_mode_object_put(obj); + obj = NULL; + } + return obj; }