[EARLY RFC][PATCH 1/4] ion: Add ION_VERSION ioctl

[John Stultz]

On Tue, Feb 19, 2019 at 12:46 PM Laura Abbott <labbott at redhat.com> wrote:
>
> On 2/15/19 12:24 PM, John Stultz wrote:
> > With all the slight interface changes ion has had
> > through its time in staging, keeping userland working
> > properly has been a pain. Assuming more churn going
> > forward, provide a proper version interface.
> >
> > Cc: Laura Abbott <labbott at redhat.com>
> > Cc: Sumit Semwal <sumit.semwal at linaro.org>
> > Cc: Liam Mark <lmark at codeaurora.org>
> > Cc: Brian Starkey <Brian.Starkey at arm.com>
> > Cc: Andrew F. Davis <afd at ti.com>
> > Cc: Alistair Strachan <astrachan at google.com>
> > Cc: dri-devel at lists.freedesktop.org
> > Signed-off-by: John Stultz <john.stultz at linaro.org>
> > ---
> >   drivers/staging/android/ion/ion-ioctl.c | 4 ++++
> >   drivers/staging/android/ion/ion.h       | 2 ++
> >   drivers/staging/android/uapi/ion.h      | 7 +++++++
> >   3 files changed, 13 insertions(+)
> >
> > diff --git a/drivers/staging/android/ion/ion-ioctl.c b/drivers/staging/android/ion/ion-ioctl.c
> > index a8d3cc4..458a9f2 100644
> > --- a/drivers/staging/android/ion/ion-ioctl.c
> > +++ b/drivers/staging/android/ion/ion-ioctl.c
> > @@ -13,6 +13,7 @@
> >   union ion_ioctl_arg {
> >       struct ion_allocation_data allocation;
> >       struct ion_heap_query query;
> > +     u32 version;
> >   };
> >
> >   static int validate_ioctl_arg(unsigned int cmd, union ion_ioctl_arg *arg)
> > @@ -86,6 +87,9 @@ long ion_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
> >       case ION_IOC_HEAP_QUERY:
> >               ret = ion_query_heaps(&data.query);
> >               break;
> > +     case ION_IOC_VERSION:
> > +             data.version = ION_VERSION;
> > +             break;
> >       default:
> >               return -ENOTTY;
> >       }
> > diff --git a/drivers/staging/android/ion/ion.h b/drivers/staging/android/ion/ion.h
> > index 47b594c..439e682 100644
> > --- a/drivers/staging/android/ion/ion.h
> > +++ b/drivers/staging/android/ion/ion.h
> > @@ -21,6 +21,8 @@
> >
> >   #include "../uapi/ion.h"
> >
> > +#define ION_VERSION 3
> > +
> >   /**
> >    * struct ion_platform_heap - defines a heap in the given platform
> >    * @type:   type of the heap from ion_heap_type enum
> > diff --git a/drivers/staging/android/uapi/ion.h b/drivers/staging/android/uapi/ion.h
> > index 5d70098..c480448 100644
> > --- a/drivers/staging/android/uapi/ion.h
> > +++ b/drivers/staging/android/uapi/ion.h
> > @@ -124,4 +124,11 @@ struct ion_heap_query {
> >   #define ION_IOC_HEAP_QUERY     _IOWR(ION_IOC_MAGIC, 8, \
> >                                       struct ion_heap_query)
> >
> > +/**
> > + * DOC: ION_IOC_VERSION - Get ION interface version
> > + *
> > + * Takes a u32 and returns the ION interface version
> > + */
> > +#define ION_IOC_VERSION              _IOR(ION_IOC_MAGIC, 9, u32)
> > +
> >   #endif /* _UAPI_LINUX_ION_H */
> >
>
> Like I said on the other thread, I was told no before
> https://lore.kernel.org/lkml/1472769644-11039-4-git-send-email-labbott@redhat.com/T/#u

Alright, then. I'm ok with dropping it. Hopefully we can just avoid
any more really subtle abi breaks.

thanks
-john