Re: [PATCH 06/21] lpfc: Fix host reset escalation killing all IOs.

[Hannes Reinecke <hare@suse.de>]

On 04/03/2015 11:11 PM, James Smart wrote:
> Fix host reset escalation killing all IOs.
> 
> SLI-3 adapters will use a new host template. The template differs
> from SLI-4 adapters in that it does not have an eh_host_reset_handler.
> 
> Lpfc has traditionally never had a host_reset. The host reset
> handler was added when we ran into a stuck hardware condition on a
> SLI-4 adapter. The host_reset will reset and reinit the pci function,
> clearing the hardware condition.
> 
> Unfortunately, the host reset handler uses attach/detach code paths,
> which makes scsi_add_host() and scsi_remove_host() calls. Meaning, a
> host_reset will completely remove the scsi_host from the system. As a
> new call to scsi_add_host() is made, the shost# changes, which results
> in completely new scsi_devices and device names. All the older scsi
> devices on the old shost# are now orphaned and unrecoverable.
> 
> We realize we need to re-implement the host_reset_handler so the scsi_host
> stays registered across the host_reset, but that will be a rather
> lengthy effort. In the short term, we had an immediate need to restore
> the SLI-3 devices to their working behavior, with the easiest path being
> to remove their host_reset handler.
> 
> Signed-off-by: Dick Kennedy <dick.kennedy@emulex.com>
> Signed-off-by: James Smart <james.smart@emulex.com>
> ---

Of course, this will disable the eh_deadline mechanism, which relies
on the host_reset to be present.

Of which you are perfectly aware :-)

So, grudgingly:

Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare@suse.de			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
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