Re: [PATCH v2 08/30] s390/pci: stash associated GISA designation

[Matthew Rosato]

On 1/24/22 9:08 AM, Pierre Morel wrote:
> On 1/14/22 21:31, Matthew Rosato wrote:
> > For passthrough devices, we will need to know the GISA designation of the
> > guest if interpretation facilities are to be used.  Setup to stash 
> > this in
> > the zdev and set a default of 0 (no GISA designation) for now; a 
> > subsequent
> > patch will set a valid GISA designation for passthrough devices.
> > Also, extend mpcific routines to specify this stashed designation as part
> > of the mpcific command.
> >
> > Reviewed-by: Niklas Schnelle <schnelle@xxxxxxxxxxxxx>
> > Reviewed-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
> > Reviewed-by: Eric Farman <farman@xxxxxxxxxxxxx>
> > Reviewed-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
> > Signed-off-by: Matthew Rosato <mjrosato@xxxxxxxxxxxxx>
> > ---
> >   arch/s390/include/asm/pci.h     | 1 +
> >   arch/s390/include/asm/pci_clp.h | 3 ++-
> >   arch/s390/pci/pci.c             | 6 ++++++
> >   arch/s390/pci/pci_clp.c         | 1 +
> >   arch/s390/pci/pci_irq.c         | 5 +++++
> >   5 files changed, 15 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h
> > index 90824be5ce9a..2474b8d30f2a 100644
> > --- a/arch/s390/include/asm/pci.h
> > +++ b/arch/s390/include/asm/pci.h
> > @@ -123,6 +123,7 @@ struct zpci_dev {
> >       enum zpci_state state;
> >       u32        fid;        /* function ID, used by sclp */
> >       u32        fh;        /* function handle, used by insn's */
> > +    u32        gd;        /* GISA designation for passthrough */
>
> I already gave my R-B, and do not want to remove it, but wouldn't it be 
> possible to use more explicit names like gisa_designation instead of 
> just gd.
> It would not change anything to the functionality but would facilitate 
> the maintenance?

Honestly, I don't have a strong opinion on this one -- AFAICT struct 
zpci_dev has a fair mix of short names (fh) and explicit names 
(max_bus_speed).

It does require changes to this patch and various subsequent patches -- 
The changes are, as you say, not functional, so I think it's not a big deal?

I do think 'gisa_designation' is too verbose though -- How about just 
'gisa', this is the same name used in the structure where we get this 
value from (gisa in struct sie_page2)

As long as nobody objects I will s/gd/gisa/ here and in struct 
clp_req_set_pci, retaining review tags.