Re: [PATCH 00/13] scsi: Core ALUA driver

[John Garry <john.g.garry@oracle.com>]

On 23/03/2026 19:45, Benjamin Marzinski wrote:
>>> I don't
>>> think the Native SCSI multipath code would need to actively interface
>>> with the device handler code to support IMPLICIT ALUA. IIUC, looking at
>>> sdev->access_state should be enough to pick the correct path.
>> We also have the functionality from alua_check_sense() to consider.
> But the multipath code won't call that directly. Right now, the scsi
> device handler will, at least for every scsi device except ones using
> the Native Multipath code. My point is that this would just work, except
> that the Native Multipath code goes out of its way to break it, by
> disabling device handlers, and I don't really see the point of disabling
> something that every other scsi device, multipathed or not, has enabled.
> It's not like leaving it enabled makes it any harder to move the
> implicit ALUA support from the device handler to the generic scsi code,
> if that's the goal, since the Native Multipath code doesn't care who is
> issuing those rtpgs and updating the state.
> 
> I guess this is more of a question for Hannes. Is the goal to turn off
> automatic device handler attachment in general, and go back to making
> dm-multipath attach device handlers to the scsi devices it is using?

I'm not answering for Hannes, but I don't think that is the goal.

> If
> not, then I don't see any reason to have the Native Multipath code
> disable it. 

It was just disabled it as we now had another method in the scsi core 
code to get ALUA info.

My plan would be - based on this series - to not attach DH just when 
using native SCSI multipath for a device.

> If it allowed device handlers to get attached, these two
> developement efforts (native scsi multipath and refactoring the alua
> support) could go on in parallel.
> 
> Or am I missing something here?

It just seems to be about this DH stuff is that there is bad history 
there and no more users are wanted.

But now I am getting bogged down in this ALUA support because of that, 
which I feared would happen.

Thanks,
John