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-rw-r--r--drivers/cpufreq/cpufreq.c8
-rw-r--r--drivers/cpufreq/cpufreq_conservative.c13
-rw-r--r--drivers/cpufreq/cpufreq_ondemand.c13
-rw-r--r--drivers/cpufreq/cpufreq_stats.c4
4 files changed, 33 insertions, 5 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 44d1eca83a72..35e0b9ceecf7 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1497,6 +1497,7 @@ int cpufreq_update_policy(unsigned int cpu)
}
EXPORT_SYMBOL(cpufreq_update_policy);
+#ifdef CONFIG_HOTPLUG_CPU
static int cpufreq_cpu_callback(struct notifier_block *nfb,
unsigned long action, void *hcpu)
{
@@ -1532,10 +1533,11 @@ static int cpufreq_cpu_callback(struct notifier_block *nfb,
return NOTIFY_OK;
}
-static struct notifier_block cpufreq_cpu_notifier =
+static struct notifier_block __cpuinitdata cpufreq_cpu_notifier =
{
.notifier_call = cpufreq_cpu_callback,
};
+#endif /* CONFIG_HOTPLUG_CPU */
/*********************************************************************
* REGISTER / UNREGISTER CPUFREQ DRIVER *
@@ -1596,7 +1598,7 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data)
}
if (!ret) {
- register_cpu_notifier(&cpufreq_cpu_notifier);
+ register_hotcpu_notifier(&cpufreq_cpu_notifier);
dprintk("driver %s up and running\n", driver_data->name);
cpufreq_debug_enable_ratelimit();
}
@@ -1628,7 +1630,7 @@ int cpufreq_unregister_driver(struct cpufreq_driver *driver)
dprintk("unregistering driver %s\n", driver->name);
sysdev_driver_unregister(&cpu_sysdev_class, &cpufreq_sysdev_driver);
- unregister_cpu_notifier(&cpufreq_cpu_notifier);
+ unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
spin_lock_irqsave(&cpufreq_driver_lock, flags);
cpufreq_driver = NULL;
diff --git a/drivers/cpufreq/cpufreq_conservative.c b/drivers/cpufreq/cpufreq_conservative.c
index e07a35487bde..b3ebc8f01975 100644
--- a/drivers/cpufreq/cpufreq_conservative.c
+++ b/drivers/cpufreq/cpufreq_conservative.c
@@ -22,6 +22,7 @@
#include <linux/types.h>
#include <linux/fs.h>
#include <linux/sysfs.h>
+#include <linux/cpu.h>
#include <linux/sched.h>
#include <linux/kmod.h>
#include <linux/workqueue.h>
@@ -72,6 +73,14 @@ static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info);
static unsigned int dbs_enable; /* number of CPUs using this policy */
+/*
+ * DEADLOCK ALERT! There is a ordering requirement between cpu_hotplug
+ * lock and dbs_mutex. cpu_hotplug lock should always be held before
+ * dbs_mutex. If any function that can potentially take cpu_hotplug lock
+ * (like __cpufreq_driver_target()) is being called with dbs_mutex taken, then
+ * cpu_hotplug lock should be taken before that. Note that cpu_hotplug lock
+ * is recursive for the same process. -Venki
+ */
static DEFINE_MUTEX (dbs_mutex);
static DECLARE_WORK (dbs_work, do_dbs_timer, NULL);
@@ -414,12 +423,14 @@ static void dbs_check_cpu(int cpu)
static void do_dbs_timer(void *data)
{
int i;
+ lock_cpu_hotplug();
mutex_lock(&dbs_mutex);
for_each_online_cpu(i)
dbs_check_cpu(i);
schedule_delayed_work(&dbs_work,
usecs_to_jiffies(dbs_tuners_ins.sampling_rate));
mutex_unlock(&dbs_mutex);
+ unlock_cpu_hotplug();
}
static inline void dbs_timer_init(void)
@@ -514,6 +525,7 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
break;
case CPUFREQ_GOV_LIMITS:
+ lock_cpu_hotplug();
mutex_lock(&dbs_mutex);
if (policy->max < this_dbs_info->cur_policy->cur)
__cpufreq_driver_target(
@@ -524,6 +536,7 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
this_dbs_info->cur_policy,
policy->min, CPUFREQ_RELATION_L);
mutex_unlock(&dbs_mutex);
+ unlock_cpu_hotplug();
break;
}
return 0;
diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
index 3e6ffcaa5af4..693e540481b4 100644
--- a/drivers/cpufreq/cpufreq_ondemand.c
+++ b/drivers/cpufreq/cpufreq_ondemand.c
@@ -21,6 +21,7 @@
#include <linux/types.h>
#include <linux/fs.h>
#include <linux/sysfs.h>
+#include <linux/cpu.h>
#include <linux/sched.h>
#include <linux/kmod.h>
#include <linux/workqueue.h>
@@ -71,6 +72,14 @@ static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info);
static unsigned int dbs_enable; /* number of CPUs using this policy */
+/*
+ * DEADLOCK ALERT! There is a ordering requirement between cpu_hotplug
+ * lock and dbs_mutex. cpu_hotplug lock should always be held before
+ * dbs_mutex. If any function that can potentially take cpu_hotplug lock
+ * (like __cpufreq_driver_target()) is being called with dbs_mutex taken, then
+ * cpu_hotplug lock should be taken before that. Note that cpu_hotplug lock
+ * is recursive for the same process. -Venki
+ */
static DEFINE_MUTEX (dbs_mutex);
static DECLARE_WORK (dbs_work, do_dbs_timer, NULL);
@@ -363,12 +372,14 @@ static void dbs_check_cpu(int cpu)
static void do_dbs_timer(void *data)
{
int i;
+ lock_cpu_hotplug();
mutex_lock(&dbs_mutex);
for_each_online_cpu(i)
dbs_check_cpu(i);
queue_delayed_work(dbs_workq, &dbs_work,
usecs_to_jiffies(dbs_tuners_ins.sampling_rate));
mutex_unlock(&dbs_mutex);
+ unlock_cpu_hotplug();
}
static inline void dbs_timer_init(void)
@@ -469,6 +480,7 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
break;
case CPUFREQ_GOV_LIMITS:
+ lock_cpu_hotplug();
mutex_lock(&dbs_mutex);
if (policy->max < this_dbs_info->cur_policy->cur)
__cpufreq_driver_target(
@@ -479,6 +491,7 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
this_dbs_info->cur_policy,
policy->min, CPUFREQ_RELATION_L);
mutex_unlock(&dbs_mutex);
+ unlock_cpu_hotplug();
break;
}
return 0;
diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c
index c576c0b3f452..145061b8472a 100644
--- a/drivers/cpufreq/cpufreq_stats.c
+++ b/drivers/cpufreq/cpufreq_stats.c
@@ -350,7 +350,7 @@ __init cpufreq_stats_init(void)
return ret;
}
- register_cpu_notifier(&cpufreq_stat_cpu_notifier);
+ register_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
lock_cpu_hotplug();
for_each_online_cpu(cpu) {
cpufreq_stat_cpu_callback(&cpufreq_stat_cpu_notifier, CPU_ONLINE,
@@ -368,7 +368,7 @@ __exit cpufreq_stats_exit(void)
CPUFREQ_POLICY_NOTIFIER);
cpufreq_unregister_notifier(&notifier_trans_block,
CPUFREQ_TRANSITION_NOTIFIER);
- unregister_cpu_notifier(&cpufreq_stat_cpu_notifier);
+ unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
lock_cpu_hotplug();
for_each_online_cpu(cpu) {
cpufreq_stat_cpu_callback(&cpufreq_stat_cpu_notifier, CPU_DEAD,
generated by cgit (git 2.34.1) at 2025-06-08 16:48:52 +0000