Re: iscsi flashnode bus? Re: [RFC PATCH 2/4] iscsi: sysfs filtering by network namespace

[Mike Christie <michaelc-hcNo3dDEHLuVc3sceRu5cw@public.gmane.org>]

On 5/21/15, 3:49 PM, Chris Leech wrote:
> On Wed, May 13, 2015 at 03:12:45PM -0700, Chris Leech wrote:
>> This makes the iscsi_host, iscsi_session, iscsi_connection, and
>> iscsi_endpoint transport class devices only visible in sysfs under a
>> matching network namespace.  The network namespace for all of these
>> objects is tracked in the iscsi_cls_host structure.
>
> I noticed that I didn't change iscsi_iface, but it should probably be
> handled the same was as iscsi_endpoint.
>
> I had intentionally skipped over all the flashnode stuff, until I had a
> chance to go back and take a closer look.
>
> Is there any particular reason why the flashnode support was implemented
> as a bus?  Following the pattern of everything else in
> scsi_transport_iscsi it should probably have been two classes
> (iscsi_flash_session and iscsi_flash_conn).  It's an issue as sysfs
> tagging only works on a per-class basis right now.
>


At some point upstream started telling us to stop using classes and use 
buses instead. It was around the time the fcoe's fcoe_sysfs stuff was 
being reviewed. In the middle of this mail is the comment about using 
buses instead of classes for fcoe:

http://www.spinics.net/lists/linux-scsi/msg58168.html

> I can see a couple of ways forward.
>
> 1) Extend sysfs tagging to work with device_type as well as class, and
>     use that for the two types on the flashnode "bus"

If we are supposed to be using buses instead of classes then I think is 
correct.

>
> 2) Change the flashnode code to use classes instead of a bus.
>     Keeping a single iscsi_flashnode class and continuing to use the two
>     device_types for sessions and connections should result in the only
>     visible change being /sys/bus/iscsi_flashnode moving to
>     /sys/class/iscsi_flashnode.

If we can use classes, this is fine with me.

>
> I prefer #2, but it looks like the open-iscsi tools would need to be
> updated (not all code paths follow the recommendations to ignore
> bus/class differences and check all subsystem locations).  And I don't
> know for sure that there aren't any other tools using this interface
> (it's only implemented for qla4xxx).
>

Ccing qlogic. I do not think any tools use it. I do not even know if 
anyone uses iscsiadm to manage it. Qlogic?


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