drm/i915: Decouple the object from the unbound list before freeing pages

As we may actually allocate in order to save the physical swizzling bits
during the free, we have to be careful not to trigger the shrinker on
the same object.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
[danvet: Added a small comment in the code to really drive the
scariness of this patch home.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 4ef8b5714337f20f7fb3a44a69c69a6cce574d1c..c1f691958f89bf1c6754a2576a3a21bff1140e86 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1696,10 +1696,14 @@ i915_gem_object_put_pages(struct drm_i915_gem_object *obj)
        if (obj->pages_pin_count)
                return -EBUSY;
 
+       /* ->put_pages might need to allocate memory for the bit17 swizzle
+        * array, hence protect them from being reaped by removing them from gtt
+        * lists early. */
+       list_del(&obj->gtt_list);
+
        ops->put_pages(obj);
        obj->pages = NULL;
 
-       list_del(&obj->gtt_list);
        if (i915_gem_object_is_purgeable(obj))
                i915_gem_object_truncate(obj);