The only thing that omap_gem_free_object does that might need the magic protection of struct_mutex (of keeping all objects alive if that lock is held, even if the last reference is gone) is the mm_list manipulation.
But that is already protected by the separate omapdrm->list_lock, which means struct_mutex is an entirely internal lock for omapdrm. Everything else is just releasing resources, which is all protected already by the various subsystems and allocators.
To make this even more obvious we could do an s/dev->struct_mutex/omapdrm->gem_lock/ like I've done for udl. But since omapdrm is a lot bigger and a lot more active I'll refrain from that - this is better done by omapdrm developers at some suitable time in the future.
v2: Just auditing the code isn't enough, I actually have to remove the now wrong locking check in omap_gem_free_object ...
Signed-off-by: Daniel Vetter daniel.vetter@intel.com Cc: Tomi Valkeinen tomi.valkeinen@ti.com --- drivers/gpu/drm/omapdrm/omap_drv.c | 2 +- drivers/gpu/drm/omapdrm/omap_gem.c | 2 -- 2 files changed, 1 insertion(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/omapdrm/omap_drv.c b/drivers/gpu/drm/omapdrm/omap_drv.c index 5fcf9eaf3eaf..5005ecc284d2 100644 --- a/drivers/gpu/drm/omapdrm/omap_drv.c +++ b/drivers/gpu/drm/omapdrm/omap_drv.c @@ -493,7 +493,7 @@ static struct drm_driver omap_drm_driver = { .prime_fd_to_handle = drm_gem_prime_fd_to_handle, .gem_prime_export = omap_gem_prime_export, .gem_prime_import = omap_gem_prime_import, - .gem_free_object = omap_gem_free_object, + .gem_free_object_unlocked = omap_gem_free_object, .gem_vm_ops = &omap_gem_vm_ops, .dumb_create = omap_gem_dumb_create, .dumb_map_offset = omap_gem_dumb_map_offset, diff --git a/drivers/gpu/drm/omapdrm/omap_gem.c b/drivers/gpu/drm/omapdrm/omap_gem.c index 183447572e90..ac4175c13ecb 100644 --- a/drivers/gpu/drm/omapdrm/omap_gem.c +++ b/drivers/gpu/drm/omapdrm/omap_gem.c @@ -1086,8 +1086,6 @@ void omap_gem_free_object(struct drm_gem_object *obj)
evict(obj);
- WARN_ON(!mutex_is_locked(&dev->struct_mutex)); - mutex_lock(&priv->list_lock); list_del(&omap_obj->mm_list); mutex_unlock(&priv->list_lock);