drm/i915: Extract vm specific part of eviction

As we'll see in the next patch, being able to evict for just 1 VM is
handy.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_gem_evict.c

@@ -155,12 +155,31 @@ found:
 	return ret;
 }
 
+static int i915_gem_evict_vm(struct i915_address_space *vm, bool do_idle)
+{
+	struct i915_vma *vma, *next;
+	int ret;
+
+	if (do_idle) {
+		ret = i915_gpu_idle(vm->dev);
+		if (ret)
+			return ret;
+
+		i915_gem_retire_requests(vm->dev);
+	}
+
+	list_for_each_entry_safe(vma, next, &vm->inactive_list, mm_list)
+		if (vma->obj->pin_count == 0)
+			WARN_ON(i915_vma_unbind(vma));
+
+	return 0;
+}
+
 int
 i915_gem_evict_everything(struct drm_device *dev)
 {
 	drm_i915_private_t *dev_priv = dev->dev_private;
 	struct i915_address_space *vm;
-	struct i915_vma *vma, *next;
 	bool lists_empty = true;
 	int ret;
 
@@ -187,11 +206,8 @@ i915_gem_evict_everything(struct drm_device *dev)
 	i915_gem_retire_requests(dev);
 
 	/* Having flushed everything, unbind() should never raise an error */
-	list_for_each_entry(vm, &dev_priv->vm_list, global_link) {
-		list_for_each_entry_safe(vma, next, &vm->inactive_list, mm_list)
-			if (vma->obj->pin_count == 0)
-				WARN_ON(i915_vma_unbind(vma));
-	}
+	list_for_each_entry(vm, &dev_priv->vm_list, global_link)
+		WARN_ON(i915_gem_evict_vm(vm, false));
 
 	return 0;
 }