[Intel-gfx] [PATCH 5/5] drm/i915: Always flush tiling changes before accessing through the GTT

[Chris Wilson]

As we defer updating the fence register from set-tiling to the point of
use, we need to declare every access through the GTT as either fenced or
unfenced.

This patches fixes an old bug in the execbuffer relocation processing
which could conceivably be hit by a pathological userspace.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_gem_execbuffer.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 2a24d0c..1a0d54f 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -381,7 +381,11 @@ i915_gem_execbuffer_relocate_entry(struct drm_i915_gem_object *obj,
 		uint32_t __iomem *reloc_entry;
 		void __iomem *reloc_page;
 
-		ret = i915_gem_object_set_to_gtt_domain(obj, 1);
+		ret = i915_gem_object_set_to_gtt_domain(obj, true);
+		if (ret)
+			return ret;
+
+		ret = i915_gem_object_put_fence(obj);
 		if (ret)
 			return ret;
 
-- 
1.7.10