Re: [PATCH RFC v3 04/22] scsi: core: Add support to send reserved commands

[John Garry]

On 27/10/2022 02:21, Damien Le Moal wrote:
> >   
> > +	if (blk_mq_is_reserved_rq(rq)) {
> > +		struct scsi_device *sdev = cmd->device;
> This variable is not really needed. You can call:
> 		
> 		scsi_device_unbusy(cmd->device, cmd);
>
> No ?

ok, your suggestion is good

> > +
> > +		scsi_mq_uninit_cmd(cmd);
> > +		scsi_device_unbusy(sdev, cmd);
> > +		__blk_mq_end_request(rq, 0);
> > +
> > +		return;
> > +	}
> > +
> >   	INIT_LIST_HEAD(&cmd->eh_entry);
> >   
> >   	atomic_inc(&cmd->device->iodone_cnt);
> > @@ -1718,6 +1728,21 @@ static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
> >   	blk_status_t ret;
> >   	int reason;
> >   
> > +	if (blk_mq_is_reserved_rq(req)) {
> > +		if (!(req->rq_flags & RQF_DONTPREP)) {
> > +			ret = scsi_prepare_cmd(req);
> > +			if (ret != BLK_STS_OK)
> > +				goto out_dec_host_busy;
> > +
> > +			req->rq_flags |= RQF_DONTPREP;
> > +		} else {
> > +			clear_bit(SCMD_STATE_COMPLETE, &cmd->state);
> > +		}
> > +		blk_mq_start_request(req);
> > +
> > +		return shost->hostt->reserved_queuecommand(shost, cmd);
> > +	}
> > +
> >   	WARN_ON_ONCE(cmd->budget_token < 0);
> >   
> >   	/*
> > diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
> > index 91678c77398e..a39f36aa0b0d 100644
> > --- a/include/scsi/scsi_host.h
> > +++ b/include/scsi/scsi_host.h
> > @@ -73,6 +73,7 @@ struct scsi_host_template {
> >   	 * STATUS: REQUIRED
> >   	 */
> >   	int (* queuecommand)(struct Scsi_Host *, struct scsi_cmnd *);
> > +	int (*reserved_queuecommand)(struct Scsi_Host *, struct scsi_cmnd *);
> Nit: This op name sound like something returning a bool... May be a
> straight "queue_reserved_command" name would be clearer ?

or queuecommand_reserved ? I'm just trying to have the name a variant of 
"queuecommand".

>

thanks,
John