cmd->request->flags &= ~REQ_DONTPREP;
scsi_unprep_request(req);
static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd){	unsigned long flags;	cmd->request->flags &= ~REQ_DONTPREP;	spin_lock_irqsave(q->queue_lock, flags);	blk_requeue_request(q, cmd->request);	spin_unlock_irqrestore(q->queue_lock, flags);	scsi_run_queue(q);}