An unfortunate sequence of events, but it turns out there is a valid usecase for being able to free/decouple the driver objects before they are freed by the DRM core. In particular, if we have a pointer into a drm core object from inside a driver object, that pointer needs to be nerfed *before* it is freed so that concurrent access (e.g. debugfs) does not following the dangling pointer.
The legacy marker was adding in the code movement from drp_fops.c to drm_file.c
References: 9acdac68bcdc ("drm: rename drm_fops.c to drm_file.c") Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Cc: Daniel Vetter daniel.vetter@intel.com Cc: Gustavo Padovan gustavo.padovan@collabora.com Cc: CQ Tang cq.tang@intel.com Cc: stable@vger.kernel.org # v4.12+ --- drivers/gpu/drm/drm_file.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c index 0ac4566ae3f4..7b4258d6f7cc 100644 --- a/drivers/gpu/drm/drm_file.c +++ b/drivers/gpu/drm/drm_file.c @@ -258,8 +258,7 @@ void drm_file_free(struct drm_file *file) (long)old_encode_dev(file->minor->kdev->devt), atomic_read(&dev->open_count));
- if (drm_core_check_feature(dev, DRIVER_LEGACY) && - dev->driver->preclose) + if (dev->driver->preclose) dev->driver->preclose(dev, file);
if (drm_core_check_feature(dev, DRIVER_LEGACY))