diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index d5bb1a3..8927485 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -327,30 +327,10 @@
 	return err;
 }
 
-struct unmap_grant_pages_callback_data
-{
-	struct completion completion;
-	int result;
-};
-
-static void unmap_grant_callback(int result,
-				 struct gntab_unmap_queue_data *data)
-{
-	struct unmap_grant_pages_callback_data* d = data->data;
-
-	d->result = result;
-	complete(&d->completion);
-}
-
 static int __unmap_grant_pages(struct grant_map *map, int offset, int pages)
 {
 	int i, err = 0;
 	struct gntab_unmap_queue_data unmap_data;
-	struct unmap_grant_pages_callback_data data;
-
-	init_completion(&data.completion);
-	unmap_data.data = &data;
-	unmap_data.done= &unmap_grant_callback;
 
 	if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) {
 		int pgno = (map->notify.addr >> PAGE_SHIFT);
@@ -367,11 +347,9 @@
 	unmap_data.pages = map->pages + offset;
 	unmap_data.count = pages;
 
-	gnttab_unmap_refs_async(&unmap_data);
-
-	wait_for_completion(&data.completion);
-	if (data.result)
-		return data.result;
+	err = gnttab_unmap_refs_sync(&unmap_data);
+	if (err)
+		return err;
 
 	for (i = 0; i < pages; i++) {
 		if (map->unmap_ops[offset+i].status)