Re: [RFC PATCH 00/12] Ion cleanup in preparation for moving out of staging

From: Rob Clark
Date: Mon Mar 13 2017 - 17:29:51 EST

On Mon, Mar 13, 2017 at 5:09 PM, Laura Abbott <labbott@xxxxxxxxxx> wrote:
>> Hm, we might want to expose all the heaps as individual
>> /dev/ion_$heapname nodes? Should we do this from the start, since
>> we're massively revamping the uapi anyway (imo not needed, current
>> state seems to work too)?
>> -Daniel
> I thought about that. One advantage with separate /dev/ion_$heap
> is that we don't have to worry about a limit of 32 possible
> heaps per system (32-bit heap id allocation field). But dealing
> with an ioctl seems easier than names. Userspace might be less
> likely to hardcode random id numbers vs. names as well.

other advantage, I think, is selinux (brought up elsewhere on this
thread).. heaps at known fixed PAs are useful for certain sorts of
attacks so being able to restrict access more easily seems like a good