/* Mark this request as flush request, so that dm_request_fn() can recognize.  */
static void dm_rq_prepare_flush(struct request_queue *q, struct request *rq)
/* Mark this request as flush request, so that dm_request_fn() can recognize.  */
static void dm_rq_prepare_flush(struct request_queue *q, struct request *rq)
{
	rq->cmd_type = REQ_TYPE_LINUX_BLOCK;
	rq->cmd[0] = REQ_LB_OP_FLUSH;
}