Stephen Hemminger wrote:

+/***
+ * mod_timer_noact - modify a timer's timeout
+ * @timer: the timer to be modified
+ *
+ * mod_timer_noact works like mod_timer except that it doesn't activate an
+ * inactive timer, instead it returns without updating timer->expires.
+ *
+ * The function returns whether it has modified a pending timer or not.
+ * (ie. mod_timer_noact() of an inactive timer returns 0, mod_timer_noact() of
+ * an active timer returns 1.)
+ */
+int mod_timer_noact(struct timer_list *timer, unsigned long expires)
+{
+	BUG_ON(!timer->function);
+
+	/*
+	 * This is a common optimization triggered by the
+	 * networking code - if the timer is re-modified
+	 * to be the same thing then just return:
+	 */
+	if (timer->expires == expires && timer_pending(timer))
+		return 1;

This doesn't seem right, since it uses TIMER_NOACT below, there's
no point in checking for timer_pending() I think.

+
+	return __mod_timer(timer, expires, TIMER_NOACT);
+}
+
+EXPORT_SYMBOL(mod_timer_noact);
+