From 340fbd8ca1c7d6006a6b6afe716c10007bbfde85 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Thu, 22 May 2014 09:16:52 +0100
Subject: [PATCH] drm/i915: Only discard backing storage on releasing the last
 ref

Before purging our pages (as opposed to copying back the contents from
the GPU), make sure that there is not an exposed CPU mmapping through
which the user can inspect the results.

Regression from

commit 5537252b6b6d71fb1a8ed7395a8e5babf91953fd
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Tue Mar 25 13:23:06 2014 +0000

    drm/i915: Invalidate our pages under memory pressure

Testcase: igt/gem_mmap/new-object
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=79005
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Tested-by: Guo Jinxian <jinxianx.guo@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
Reading git-format-patch failed