is_rwsem_reader_owned
extern bool is_rwsem_reader_owned(struct rw_semaphore *sem);
rwsem_blocked_by = is_rwsem_reader_owned(
DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem);
DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem);
DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem);