From: Hannes Reinecke <hare@suse.de>
To: Kashyap Desai <kashyap.desai@avagotech.com>, linux-scsi@vger.kernel.org
Subject: Re: Scsi Error handling query
Date: Fri, 27 Mar 2015 17:02:16 +0100 [thread overview]
Message-ID: <55157F08.3070707@suse.de> (raw)
In-Reply-To: <bc74695bc632f3cda3ccec360eb6e0ae@mail.gmail.com>
On 03/26/2015 07:43 PM, Kashyap Desai wrote:
>> -----Original Message-----
>> From: Hannes Reinecke [mailto:hare@suse.de]
>> Sent: Thursday, March 26, 2015 9:28 PM
>> To: Kashyap Desai; linux-scsi@vger.kernel.org
>> Subject: Re: Scsi Error handling query
>>
>> On 03/26/2015 02:38 PM, Kashyap Desai wrote:
>>> Hi Hannes,
>>>
>>> I was going through one of the slide posted at below link.
>>>
>>> http://events.linuxfoundation.org/sites/events/files/slides/SCSI-EH.pd
>>> f
>>>
>>> Slide #59 has below data. I was trying to correlate with latest
>>> upstream code, but do not understand few things. Does Linux handle
>>> blocking I/O to the device and target before it actually start legacy EH
>> recovery ?
>>
>> Yes. This is handled by 'scsi_eh_scmd_add()', which adds the command to
>> the
>> internal 'eh_entry' list and starts recovery once all remaining
>> outstanding
>> commands are completed.
>
> Thanks Hannes..! Scsi_eh_scmd_add() move shost state to recovery, so it
> means blocking further IO to the Host and not really a limited to
> Device/Target for which command was timed out. Right ?
> I understood that, new improvement of scsi error handling will allow IOs to
> the other Devices attached to the host except the IO belongs to specific
> target.
>
> Also, one more thing to clarify... In presentation, term "task set aborts"
> was used. Does this mean task set abort is handled as traversing complete
> list of timed out command and sending individual TASK ABORT ?
>
No. The idea was to send 'task set aborts' as a single TMF.
However, I'm not sure if I'll be going ahead with that one; once
we've issued a 'transport reset the commands will be cone anyway.
Cheers,
Hannes
--
Dr. Hannes Reinecke zSeries & Storage
hare@suse.de +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)
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next prev parent reply other threads:[~2015-03-27 16:02 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-26 13:38 Scsi Error handling query Kashyap Desai
2015-03-26 15:57 ` Hannes Reinecke
2015-03-26 18:43 ` Kashyap Desai
2015-03-27 16:02 ` Hannes Reinecke [this message]
2015-03-30 11:45 ` Kashyap Desai
2015-03-30 15:12 ` Hannes Reinecke
2015-03-31 13:33 ` Kashyap Desai
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