[EARLY RFC][PATCH 0/4] ION per heap devices

[John Stultz]

On Tue, Feb 19, 2019 at 1:25 PM Laura Abbott <labbott at redhat.com> wrote:
>
> On 2/15/19 12:24 PM, John Stultz wrote:
> > This is a *very early RFC* (it builds, that's all I'll say :)
> > but I wanted to share it to get some initial feedback before I
> > go down the rabit hole of trying to adapt the Android userland
> > code to get this fully validated.
> >
> > This patchset tries to implement the per-heap devices for ION.
> > The main benefit is that it avoids multiplexing heap operations
> > through the /dev/ion interface, and allows for each heap to have
> > its own permissions/sepolicy rules.
> >
> > Feedback would be greatly appreciated!
> > thanks
> > -john
> >
> > 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
> >
> > John Stultz (4):
> >    ion: Add ION_VERSION ioctl
> >    ion: Initial hack to create per heap devices
> >    ion: Add HEAP_INFO ioctl to be able to fetch heap type
> >    ion: Make "legacy" /dev/ion support optional
> >
> >   drivers/staging/android/ion/Kconfig     |  7 +++
> >   drivers/staging/android/ion/ion-ioctl.c | 80 +++++++++++++++++++++++++++++++++
> >   drivers/staging/android/ion/ion.c       | 51 ++++++++++++++++-----
> >   drivers/staging/android/ion/ion.h       |  6 +++
> >   drivers/staging/android/uapi/ion.h      | 57 +++++++++++++++++++++++
> >   5 files changed, 191 insertions(+), 10 deletions(-)
> >
>
> So it occurs to me if this is going to be a new ABI
> all together maybe we should just declare a new allocation ioctl
> to be used with it. We can keep the old ioctls around
> for legacy use cases and maybe eventually delete them
> and just use the new allocation ioctl with the new
> split heaps.

So... I did add ION_IOC_HEAP_ALLOC in my patchset.  Or are you
suggesting we use a new ION_IOC_MAGIC value for the new ABI? Or some
larger rework?

thanks
-john