[PATCH 3/3] drm/gem: start adding support for per-file object mmaps

[Chris Wilson]

From: Chris Wilson <chris at chris-wilson.co.uk>
Subject: Re: [proof-of-concept/rfc] per object file mmaps
To: Dave Airlie <airlied at gmail.com>, dri-devel at lists.freedesktop.org
In-Reply-To: <1355892119-13926-1-git-send-email-airlied at gmail.com>
References: <1355892119-13926-1-git-send-email-airlied at gmail.com>

On Wed, 19 Dec 2012 14:41:56 +1000, Dave Airlie <airlied at gmail.com> wrote:
> The 2+3 patches are actually the code, the first was just a cleanup.
> 
> Anyways the second patch describes it best, but I've taken the approach
> that we just need to keep track of what filp this object has had a handle
> created on, and block mmaps on it. We could also probably block a bit
> more explicitly in the driver respective mmap offset retrieval ioctls,
> however we need to block in mmap itself to stop people just picking misc
> address and trying them.
> 
> It doesn't really add much now, but with render nodes where we have flink_to
> or fd passing it would be more useful.
> 
> I've no idea if I'll get to do much more with this, so consider it an
> indication of how I'd like it done for someone else to run with :-)

Locking looks entirely non-existent for per-file mmap add/remove in the
generic gem code. Also we have a pair of hooks there that look like they
would be a convenient point to place that code.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre