uverbs_try_lock_object
ret = uverbs_try_lock_object(uobj, UVERBS_LOOKUP_WRITE);
ret = uverbs_try_lock_object(uobj, mode);
WARN_ON(uverbs_try_lock_object(uobj, UVERBS_LOOKUP_WRITE));
WARN_ON(uverbs_try_lock_object(obj, UVERBS_LOOKUP_WRITE));