drm/i915: Unbind any residual objects/vma from the Global GTT on shutdown

We may unload the PCI device before all users (such as dma-buf) are
completely shutdown. This may leave VMA in the global GTT which we want
to revoke, whilst keeping the objects themselves around to service the
dma-buf.
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/20170210163523.17533-2-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_gem_gtt.c

@@ -2818,6 +2818,15 @@ int i915_gem_init_ggtt(struct drm_i915_private *dev_priv)
 void i915_ggtt_cleanup_hw(struct drm_i915_private *dev_priv)
 {
 	struct i915_ggtt *ggtt = &dev_priv->ggtt;
+	struct i915_vma *vma, *vn;
+
+	ggtt->base.closed = true;
+
+	mutex_lock(&dev_priv->drm.struct_mutex);
+	WARN_ON(!list_empty(&ggtt->base.active_list));
+	list_for_each_entry_safe(vma, vn, &ggtt->base.inactive_list, vm_link)
+		WARN_ON(i915_vma_unbind(vma));
+	mutex_unlock(&dev_priv->drm.struct_mutex);
 
 	if (dev_priv->mm.aliasing_ppgtt) {
 		struct i915_hw_ppgtt *ppgtt = dev_priv->mm.aliasing_ppgtt;