Re: [PATCH] scsi: target: core: Add a way to hide a port group

[Dmitry Bogdanov <d.bogdanov@yadro.com>]

On Wed, Sep 07, 2022 at 03:01:00PM -0500, Mike Christie wrote:
> 
> On 9/6/22 2:49 AM, Dmitry Bogdanov wrote:
> > From: Roman Bolshakov <r.bolshakov@yadro.com>
> >
> > Default target port group is always returned in the list of port groups,
> > even if the behaviour is unwanted, i.e. it has no members and
> > non-default port groups are primary port groups.
> >
> > A new port group attribute - "hidden" can be used to hide empty port
> > groups with no ports in REPORT TARGET PORT GROUPS, including default
> > target port group:
> >
> >   echo 1 > $DEVICE/alua/default_tg_pt_gp/hidden
> >
> 
> How about "enable"? I think that fits how we handle other objects like
> targets that are setup automatically but are not yet usable (can't login
> or reported in discovery commands) and devices we have setup but are not
> reported in commands like REPORT_LUNs (technically you need to enable and
> map them but you get the idea I'm going for).
There is already an enable semantic. It is pg_pt_gp_id field. Until it
(id) is not set the port group is treated as disabled and it is not
reported in RTPG. But the default_tg_pt_gp is enabled by default and can
not be deleted.

The patch solves the presence of non-deletable empty default_tg_pt_gp
in RTPG.
May be, a global attribute like target/core/alua/hide_emtpy_tpg would
fit better than an attribute per each port group?

I would always hide the empty default_lu_gp (not configurable) but I am
afraid that it will be considered as not backward compatible change. :(

BR,
 Dmitry