+ struct hlist_node *n;
+
+ /*
+ * RCU here will block mmu_notifier_unregister until
+ * ->release returns.
+ */
+ rcu_read_lock();
+ hlist_for_each_entry_rcu(mn, n, &mm->mmu_notifier_mm->list, hlist)
+ /*
+ * if ->release runs before mmu_notifier_unregister it
+ * must be handled as it's the only way for the driver
+ * to flush all existing sptes and stop the driver
+ * from establishing any more sptes before all the
+ * pages in the mm are freed.
+ */
+ if (mn->ops->release)
+ mn->ops->release(mn, mm);
+ rcu_read_unlock();