[dm-devel] [PATCH 3/3] dm mpath: add support for using previously attached scsi_dh

[Hannes Reinecke]

On 05/08/2012 05:19 AM, Mike Snitzer wrote:
> Use the previously attached scsi_dh if "default" is provided as the
> hardware handler name (the new 'use_default_hw_handler' flag is set in
> the multipath structure).
> 
> Leverage scsi_dh_attach's ability to increment the scsi_dh's reference
> count if the same scsi_dh name is provided when attaching -- currently
> attached scsi_dh name is determined with scsi_dh_attached_handler_name.
> 
Not sure it that's the correct way.

Using 'default' as the hardware handler name has the drawback that
the original information (ie the original hardware handler name)
is lost.

So if there is no 'default', eg if the kernel module hasn't been
loaded, we wouldn't know which hardware handler to load.

I'd rather have a feature 'default_hw_handler' which then could be
passed into the kernel module. With that we would retain both, the
original implementation and the default case.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare at suse.de			      +49 911 74053 688
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