diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index 3e3603f..880798a 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -492,13 +492,11 @@
 
 	pr_debug("priv %p\n", priv);
 
-	spin_lock(&priv->lock);
 	while (!list_empty(&priv->maps)) {
 		map = list_entry(priv->maps.next, struct grant_map, next);
 		list_del(&map->next);
 		gntdev_put_map(map);
 	}
-	spin_unlock(&priv->lock);
 
 	if (use_ptemod)
 		mmu_notifier_unregister(&priv->mn, priv->mm);
@@ -562,10 +560,11 @@
 	map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count);
 	if (map) {
 		list_del(&map->next);
-		gntdev_put_map(map);
 		err = 0;
 	}
 	spin_unlock(&priv->lock);
+	if (map)
+		gntdev_put_map(map);
 	return err;
 }