+static DEFINE_SPINLOCK(delayed_fput_lock);
+static LIST_HEAD(delayed_fput_list);
+static void delayed_fput(struct work_struct *unused)
+{
+ LIST_HEAD(head);
+ spin_lock_irq(&delayed_fput_lock);
+ list_splice_init(&delayed_fput_list, &head);
+ spin_unlock_irq(&delayed_fput_lock);
+ while (!list_empty(&head)) {
+ struct file *f = list_first_entry(&head, struct file, f_u.fu_list);
+ list_del_init(&f->f_u.fu_list);
+ __fput(f);
+ }
+}
+
+static void ____fput(struct callback_head *work)
+{
+ __fput(container_of(work, struct file, f_u.fu_rcuhead));
+}
+
+/*
+ * If kernel thread really needs to have the final fput() it has done
+ * to complete, call this. The only user right now is the boot - we
+ * *do* need to make sure our writes to binaries on initramfs has
+ * not left us with opened struct file waiting for __fput() - execve()
+ * won't work without that. Please, don't add more callers without
+ * very good reasons; in particular, never call that with locks
+ * held and never call that from a thread that might need to do
+ * some work on any kind of umount.
+ */
+void flush_delayed_fput(void)
+{
+ delayed_fput(NULL);
+}
+
+static DECLARE_WORK(delayed_fput_work, delayed_fput);
+