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

Heiko Carstens
2022-05-18T11:47:34Z

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.