[LSF/MM TOPIC] [ATTEND] scsi_eh updates

[LSF/MM TOPIC] [ATTEND] scsi_eh updates

[Hannes Reinecke]

Hi all,

(before leaving for holiday ...)

I'd like to attend LSF 2014.

During that I'd like to discuss the current status of the SCSI EH
and the future planned updates.

As discussed during last year's LSF the SCSI error handler should be
updated to handle modern SCSI transports better.
While some patchsets are already merged, there are some issues which
are still open:
- Handling of requests during host reset:
  Do we need to keep hold of outstanding requests during host reset?
  Or is it save to return them prior to host reset?
- Check for transport status prior to sending TMFs.
  Task management functions typically need a working I_T nexus,
  so it does make sense to first check the transport status
  prior to attempting any TMFs
- Further steps for updating SCSI EH
As these are tricky issues which have possible repercussions on the
entire subsystem and LLDDs it'd be good to have a broader discussion
here.

Happy X-mas,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare@suse.de			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)
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Re: [LSF/MM TOPIC] [ATTEND] scsi_eh updates

[Nicholas A. Bellinger]

On Fri, 2013-12-20 at 15:54 +0100, Hannes Reinecke wrote:
> Hi all,
> 
> (before leaving for holiday ...)
> 
> I'd like to attend LSF 2014.
> 
> During that I'd like to discuss the current status of the SCSI EH
> and the future planned updates.
> 
> As discussed during last year's LSF the SCSI error handler should be
> updated to handle modern SCSI transports better.
> While some patchsets are already merged, there are some issues which
> are still open:
> - Handling of requests during host reset:
>   Do we need to keep hold of outstanding requests during host reset?
>   Or is it save to return them prior to host reset?
> - Check for transport status prior to sending TMFs.
>   Task management functions typically need a working I_T nexus,
>   so it does make sense to first check the transport status
>   prior to attempting any TMFs
> - Further steps for updating SCSI EH
> As these are tricky issues which have possible repercussions on the
> entire subsystem and LLDDs it'd be good to have a broader discussion
> here.

+1 on this too.

Without upstream movement on scsi_eh, it's going to be a long and
painful road for scsi-mq.

--nab

Re: [LSF/MM TOPIC] [ATTEND] scsi_eh updates

[Bart Van Assche]

On 12/20/13 15:54, Hannes Reinecke wrote:
> I'd like to attend LSF 2014.
> 
> During that I'd like to discuss the current status of the SCSI EH
> and the future planned updates.
> 
> As discussed during last year's LSF the SCSI error handler should be
> updated to handle modern SCSI transports better.
> While some patchsets are already merged, there are some issues which
> are still open:
> - Handling of requests during host reset:
>   Do we need to keep hold of outstanding requests during host reset?
>   Or is it save to return them prior to host reset?
> - Check for transport status prior to sending TMFs.
>   Task management functions typically need a working I_T nexus,
>   so it does make sense to first check the transport status
>   prior to attempting any TMFs
> - Further steps for updating SCSI EH
> As these are tricky issues which have possible repercussions on the
> entire subsystem and LLDDs it'd be good to have a broader discussion
> here.

+1 for this topic.

Given my recent contributions to the error detection and recovery code
in the SRP initiator driver I think I can provide valuable inputs for
this discussion.

Bart.

Re: [LSF/MM TOPIC] [ATTEND] scsi_eh updates

[Giridhar Malavali]

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On 12/20/13 6:54 AM, "Hannes Reinecke" <hare@suse.de> wrote:

>Hi all,
>
>(before leaving for holiday ...)
>
>I'd like to attend LSF 2014.
>
>During that I'd like to discuss the current status of the SCSI EH
>and the future planned updates.
>
>As discussed during last year's LSF the SCSI error handler should be
>updated to handle modern SCSI transports better.
>While some patchsets are already merged, there are some issues which
>are still open:
>- Handling of requests during host reset:
>  Do we need to keep hold of outstanding requests during host reset?
>  Or is it save to return them prior to host reset?
>- Check for transport status prior to sending TMFs.
>  Task management functions typically need a working I_T nexus,
>  so it does make sense to first check the transport status
>  prior to attempting any TMFs
>- Further steps for updating SCSI EH
>As these are tricky issues which have possible repercussions on the
>entire subsystem and LLDDs it'd be good to have a broader discussion
>here.

+1

I would like to participate in this discussion to provide inputs from
LLDDs.

-- Giri 


>
>Happy X-mas,
>
>Hannes
>-- 
>Dr. Hannes Reinecke		      zSeries & Storage
>hare@suse.de			      +49 911 74053 688
>SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
>GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)
>--
>To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
>the body of a message to majordomo@vger.kernel.org
>More majordomo info at  http://vger.kernel.org/majordomo-info.html


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Re: [LSF/MM TOPIC] [ATTEND] scsi_eh updates

[James Bottomley]

On Mon, 2014-01-20 at 18:44 +0000, Giridhar Malavali wrote:
> 
> On 12/20/13 6:54 AM, "Hannes Reinecke" <hare@suse.de> wrote:
> 
> >Hi all,
> >
> >(before leaving for holiday ...)
> >
> >I'd like to attend LSF 2014.
> >
> >During that I'd like to discuss the current status of the SCSI EH
> >and the future planned updates.
> >
> >As discussed during last year's LSF the SCSI error handler should be
> >updated to handle modern SCSI transports better.
> >While some patchsets are already merged, there are some issues which
> >are still open:
> >- Handling of requests during host reset:
> >  Do we need to keep hold of outstanding requests during host reset?
> >  Or is it save to return them prior to host reset?
> >- Check for transport status prior to sending TMFs.
> >  Task management functions typically need a working I_T nexus,
> >  so it does make sense to first check the transport status
> >  prior to attempting any TMFs
> >- Further steps for updating SCSI EH
> >As these are tricky issues which have possible repercussions on the
> >entire subsystem and LLDDs it'd be good to have a broader discussion
> >here.
> 
> +1
> 
> I would like to participate in this discussion to provide inputs from
> LLDDs.

For the last time, this isn't the way to ask for a place.  You need to
send in an ATTEND request according to the CFP.

http://marc.info/?l=linux-scsi&m=138753185305739

Thanks,

James

Re: [LSF/MM TOPIC] [ATTEND] scsi_eh updates

[Hannes Reinecke]

On 01/20/2014 07:44 PM, Giridhar Malavali wrote:
> 
> 
> On 12/20/13 6:54 AM, "Hannes Reinecke" <hare@suse.de> wrote:
> 
[ .. ]
>>
>> As discussed during last year's LSF the SCSI error handler should be
>> updated to handle modern SCSI transports better.
>> While some patchsets are already merged, there are some issues which
>> are still open:
>> - Handling of requests during host reset:
>>  Do we need to keep hold of outstanding requests during host reset?
>>  Or is it save to return them prior to host reset?
>> - Check for transport status prior to sending TMFs.
>>  Task management functions typically need a working I_T nexus,
>>  so it does make sense to first check the transport status
>>  prior to attempting any TMFs
>> - Further steps for updating SCSI EH
>> As these are tricky issues which have possible repercussions on the
>> entire subsystem and LLDDs it'd be good to have a broader discussion
>> here.
> 
> +1
> 
> I would like to participate in this discussion to provide inputs from
> LLDDs.
> 
And I would _very_ much like to have participation from LLDD
vendors/providers; as part of the scsi_eh update I plan to introduce
a new callback 'eh_transport_reset'.
Which need to be implemented at the LLDD level.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare@suse.de			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)
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To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
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More majordomo info at  http://vger.kernel.org/majordomo-info.html