drm/i915: Mark all non-vma being inserted into the address spaces

We need to distinguish between full i915_vma structs and simple
drm_mm_nodes when considering eviction (i.e. we must be careful not to
treat a mere drm_mm_node as a much larger i915_vma causing memory
corruption, if we are lucky). To do this, color these not-a-vma with -1
(I915_COLOR_UNEVICTABLE).

v2...v200: New name for -1.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161205142941.21965-1-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 985142c..5f164ad 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -437,7 +437,7 @@ static void *reloc_iomap(struct drm_i915_gem_object *obj,
 			memset(&cache->node, 0, sizeof(cache->node));
 			ret = drm_mm_insert_node_in_range_generic
 				(&ggtt->base.mm, &cache->node,
-				 4096, 0, 0,
+				 4096, 0, I915_COLOR_UNEVICTABLE,
 				 0, ggtt->mappable_end,
 				 DRM_MM_SEARCH_DEFAULT,
 				 DRM_MM_CREATE_DEFAULT);