Re: [PATCH] Use queuedata accessors for device handler

[Hannes Reinecke <hare@suse.de>]

On 08/22/2011 04:45 PM, Christoph Hellwig wrote:
> On Mon, Aug 22, 2011 at 03:35:43PM +0200, Hannes Reinecke wrote:
>>
>> Starting multipath on a cciss device will cause a kernel
>> warning to be triggered. Problem is that we're using the
>> ->queuedata field of the request_queue to dereference the
>> scsi device; however, for other (non-SCSI) devices this
>> points to a totally different structure.
>> So we should rather be using accessors here to make
>> sure ->queuedata points to a valid sdev.
>
> How do we match to attach a scsi device handler to a non-scsi queue?
> I suspect that is the fundamental issue that needs addressing.
>
We don't. SCSI device handler are only for SCSI devices, not block 
devices. But scsi_dh_attach() and scsi_dh_detach() is called from 
dm-mpath.c:parse_path(), and this doesn't have any idea about the 
underlying device type.

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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