once_disable_jump(once_key, mod);
}
EXPORT_SYMBOL(__do_once_done);
+
+static DEFINE_MUTEX(once_mutex);
+
+bool __do_once_slow_start(bool *done)
+ __acquires(once_mutex)
+{
+ mutex_lock(&once_mutex);
+ if (*done) {
+ mutex_unlock(&once_mutex);
+ /* Keep sparse happy by restoring an even lock count on
+ * this mutex. In case we return here, we don't call into
+ * __do_once_done but return early in the DO_ONCE_SLOW() macro.
+ */
+ __acquire(once_mutex);
+ return false;
+ }
+
+ return true;
+}
+EXPORT_SYMBOL(__do_once_slow_start);
+
+void __do_once_slow_done(bool *done, struct static_key_true *once_key,
+ struct module *mod)
+ __releases(once_mutex)
+{
+ *done = true;
+ mutex_unlock(&once_mutex);
+ once_disable_jump(once_key, mod);
+}
+EXPORT_SYMBOL(__do_once_slow_done);