Re: [PATCH 18/22] mm: mark DEVICE_PUBLIC as broken

[Ralph Campbell]

On 6/13/19 12:44 PM, Jason Gunthorpe wrote:
> On Thu, Jun 13, 2019 at 11:43:21AM +0200, Christoph Hellwig wrote:
> > The code hasn't been used since it was added to the tree, and doesn't
> > appear to actually be usable.  Mark it as BROKEN until either a user
> > comes along or we finally give up on it.
> >
> > Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> >   mm/Kconfig | 1 +
> >   1 file changed, 1 insertion(+)
> >
> > diff --git a/mm/Kconfig b/mm/Kconfig
> > index 0d2ba7e1f43e..406fa45e9ecc 100644
> > +++ b/mm/Kconfig
> > @@ -721,6 +721,7 @@ config DEVICE_PRIVATE
> >   config DEVICE_PUBLIC
> >   	bool "Addressable device memory (like GPU memory)"
> >   	depends on ARCH_HAS_HMM
> > +	depends on BROKEN
> >   	select HMM
> >   	select DEV_PAGEMAP_OPS
>
> This seems a bit harsh, we do have another kconfig that selects this
> one today:
>
> config DRM_NOUVEAU_SVM
>          bool "(EXPERIMENTAL) Enable SVM (Shared Virtual Memory) support"
>          depends on ARCH_HAS_HMM
>          depends on DRM_NOUVEAU
>          depends on STAGING
>          select HMM_MIRROR
>          select DEVICE_PRIVATE
>          default n
>          help
>            Say Y here if you want to enable experimental support for
>            Shared Virtual Memory (SVM).
>
> Maybe it should be depends on STAGING not broken?
>
> or maybe nouveau_svm doesn't actually need DEVICE_PRIVATE?
>
> Jason

I think you are confusing DEVICE_PRIVATE for DEVICE_PUBLIC.
DRM_NOUVEAU_SVM does use DEVICE_PRIVATE but not DEVICE_PUBLIC.