From 74212ca432982903d0fc6a0f282b199e000ad8b1 Mon Sep 17 00:00:00 2001
From: Cesar Eduardo Barros <cesarb@cesarb.net>
Date: Sat, 16 Feb 2008 08:41:24 -0200
Subject: [PATCH] [CPUFREQ] Warn when cpufreq_register_notifier called before
pure initcalls
If cpufreq_register_notifier is called before pure initcalls,
init_cpufreq_transition_notifier_list will overwrite whatever it did,
causing notifiers to be ignored.
Print some noise to the kernel log if that happens.
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Signed-off-by: Dave Jones <davej@codemonkey.org.uk>
---
drivers/cpufreq/cpufreq.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index be78c07f72c..d3575f5ec6d 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -118,9 +118,11 @@ static void handle_update(struct work_struct *work);
static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
static struct srcu_notifier_head cpufreq_transition_notifier_list;
+static bool init_cpufreq_transition_notifier_list_called;
static int __init init_cpufreq_transition_notifier_list(void)
{
srcu_init_notifier_head(&cpufreq_transition_notifier_list);
+ init_cpufreq_transition_notifier_list_called = true;
return 0;
}
pure_initcall(init_cpufreq_transition_notifier_list);
@@ -1367,6 +1369,8 @@ int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
{
int ret;
+ WARN_ON(!init_cpufreq_transition_notifier_list_called);
+
switch (list) {
case CPUFREQ_TRANSITION_NOTIFIER:
ret = srcu_notifier_chain_register(
--
2.25.4