drm/i915: release the GTT mmaps when going into D3

So we'll get a fault when someone tries to access the mmap, then we'll
wake up from D3.

v2: - Rebase
v3: - Use gtt active/inactive

Testcase: igt/pm_pc8/gem-mmap-gtt
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@gmail.com>
[danvet: Add comment + WARN as discussed with Paulo on irc.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.c

@@ -917,6 +917,8 @@ static int i915_runtime_suspend(struct device *device)
 
 	DRM_DEBUG_KMS("Suspending device\n");
 
+	i915_gem_release_all_mmaps(dev_priv);
+
 	del_timer_sync(&dev_priv->gpu_error.hangcheck_timer);
 	dev_priv->pm.suspended = true;
 	intel_opregion_notify_adapter(dev, PCI_D3cold);

drivers/gpu/drm/i915/i915_drv.h

@@ -2015,6 +2015,7 @@ void i915_gem_object_unpin(struct drm_i915_gem_object *obj);
 int __must_check i915_vma_unbind(struct i915_vma *vma);
 int __must_check i915_gem_object_ggtt_unbind(struct drm_i915_gem_object *obj);
 int i915_gem_object_put_pages(struct drm_i915_gem_object *obj);
+void i915_gem_release_all_mmaps(struct drm_i915_private *dev_priv);
 void i915_gem_release_mmap(struct drm_i915_gem_object *obj);
 void i915_gem_lastclose(struct drm_device *dev);
 

drivers/gpu/drm/i915/i915_gem.c

@@ -1465,6 +1465,22 @@ out:
 	return ret;
 }
 
+void i915_gem_release_all_mmaps(struct drm_i915_private *dev_priv)
+{
+	struct i915_vma *vma;
+
+	/*
+	 * Only the global gtt is relevant for gtt memory mappings, so restrict
+	 * list traversal to objects bound into the global address space. Note
+	 * that the active list should be empty, but better safe than sorry.
+	 */
+	WARN_ON(!list_empty(&dev_priv->gtt.base.active_list));
+	list_for_each_entry(vma, &dev_priv->gtt.base.active_list, mm_list)
+		i915_gem_release_mmap(vma->obj);
+	list_for_each_entry(vma, &dev_priv->gtt.base.inactive_list, mm_list)
+		i915_gem_release_mmap(vma->obj);
+}
+
 /**
  * i915_gem_release_mmap - remove physical page mappings
  * @obj: obj in question