Re: [PATCHv3] scsi: disable automatic target scan

[Benjamin Block <bblock@linux.vnet.ibm.com>]

On 09:29 Fri 01 Apr     , Hannes Reinecke wrote:
> On 03/30/2016 09:41 PM, Benjamin Block wrote:
> > Hello Hannes,
> > 
> > I am a bit late here, but as this got pulled and Steffen didn't have
> > time to give it a review, I did today.
> > 
> > On 08:39 Thu 17 Mar     , Hannes Reinecke wrote:
> >> On larger installations it is useful to disable automatic LUN
> >> scanning, and only add the required LUNs via udev rules.
> >> This can speed up bootup dramatically.
> >>
> >> This patch introduces a new scan module parameter value 'manual',
> >> which works like 'none', but can be overriden by setting the 'rescan'
> >> value from scsi_scan_target to 'SCSI_SCAN_MANUAL'.
> >> And it updates all relevant callers to set the 'rescan' value
> >> to 'SCSI_SCAN_MANUAL' if invoked via the 'scan' option in sysfs.
> >>
> >> Signed-off-by: Hannes Reinecke <hare@suse.de>
> >> ---
> > 
> > [:snip:]
> > 
> >>
> >> diff --git a/drivers/s390/scsi/zfcp_unit.c b/drivers/s390/scsi/zfcp_unit.c
> >> index 157d3d2..08bba7c 100644
> >> --- a/drivers/s390/scsi/zfcp_unit.c
> >> +++ b/drivers/s390/scsi/zfcp_unit.c
> >> @@ -26,7 +26,8 @@ void zfcp_unit_scsi_scan(struct zfcp_unit *unit)
> >>  	lun = scsilun_to_int((struct scsi_lun *) &unit->fcp_lun);
> >>
> >>  	if (rport && rport->port_state == FC_PORTSTATE_ONLINE)
> >> -		scsi_scan_target(&rport->dev, 0, rport->scsi_target_id, lun, 1);
> >> +		scsi_scan_target(&rport->dev, 0, rport->scsi_target_id, lun,
> >> +				 SCSI_SCAN_RESCAN);
> > 
> > I'd rather use the new SCSI_SCAN_MANUAL here. We don't want this to be
> > "blocked" by an attribute set in a different (new) code-path and
> > config-location.
> > 
> > This path is used by both, zfcp-recovery and -userinterfaces (sysfs) and
> > in both cases we call it with the intend that the scan is really done -
> > hence the SCSI_SCAN_MANUAL to force a scan. I'd find it very weird if
> > suddenly our users would have to additionally use yet an other config to
> > get the old interfaces working properly.
> > 
> Okay, no problem with that.
> zfcp has its own scanning rules (cf allow_lun_scan module parameter), so
> setting it to 'MANUAL' will just restore the original behaviour.
> 
> Will you be sending a patch for it?
> 

Yeah, sry, once I am through our backlog and I find time to test that
properly.



                                                    Beste Grüße / Best regards,
                                                      - Benjamin Block
-- 
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