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

[Brian Starkey <Brian.Starkey@arm.com>]

Hi John,

On Fri, Feb 15, 2019 at 12:24:08PM -0800, 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.

In general, I've always thought that having a device node per-heap is
a bit messy for userspace. Multiplexing through the single node
doesn't seem like an insurmountable problem, but the point about
permissions/sepolicy is reasonably compelling if it's a real
requirement. What would be the reasons for that?

Thanks,
-Brian

> 
> Feedback would be greatly appreciated!
> thanks
> -john
> 
> Cc: Laura Abbott <labbott@redhat.com>
> Cc: Sumit Semwal <sumit.semwal@linaro.org>
> Cc: Liam Mark <lmark@codeaurora.org>
> Cc: Brian Starkey <Brian.Starkey@arm.com>
> Cc: Andrew F. Davis <afd@ti.com>
> Cc: Alistair Strachan <astrachan@google.com>
> Cc: dri-devel@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(-)
> 
> -- 
> 2.7.4
> 
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