Re: [PATCH v4 1/2] drivers/s390/char: Add Ultravisor io device

[Steffen Eiden]

On 5/18/22 15:45, Janosch Frank wrote:
> On 5/18/22 13:47, Heiko Carstens wrote:
> > On Tue, May 10, 2022 at 02:47:23PM +0000, Steffen Eiden wrote:
> > > diff --git a/drivers/s390/char/Kconfig b/drivers/s390/char/Kconfig
> > > index 6cc4b19acf85..e9b9902abbaf 100644
> > > --- a/drivers/s390/char/Kconfig
> > > +++ b/drivers/s390/char/Kconfig
> > > @@ -100,6 +100,16 @@ config SCLP_OFB
> > >         This option enables the Open-for-Business interface to the s390
> > >         Service Element.
> > > +config S390_UV_UAPI
> > > +    def_tristate y
> > > +    prompt "Ultravisor userspace API"
> > > +    help
> > > +      Selecting exposes parts of the UV interface to userspace
> > > +      by providing a misc character device at /dev/uv.
> > > +      Using IOCTLs one can interact with the UV.
> > > +      The device is only available if the Ultravisor
> > > +      Facility (158) is present.
> >
> > Is there a reason why this is default "y"? If you think this should be
> > compiled into the kernel if used, then why allow to make it a module
> > at all?
> > Instead you could get rid of a couple if lines of code.
>
> There was a lot of discussion around this already and the "Y" was chosen 
> as auto-loading this is a pain and therefore the SCLP and CHSC-Misc set 
> it to Y and we took that as an example (Steffen spoke to Peter to get 
> guidance).
>
> I'm sure that we want the possibility to have this as a module. 
> Personally I'd choose "m" over "y" since the module is only useful for a 
> very small amount of users.

I am fine with changing "y" to "m".

Steffen