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Commit de52a2a1 authored by Maria Yu's avatar Maria Yu
Browse files

cpufreq: Use correct locking for cpufreq_cpu_data 



Use write lock when updating cpufreq_cpu_data,
and read lock when getting the policy pointer.

CRs-Fixed: 689522
Change-Id: I454f0d575157b3411d369e04097386f50aeaaa1c
Signed-off-by: default avatarMaria Yu <aiquny@codeaurora.org>
parent 2a27b376

drivers/cpufreq/cpufreq.c

+14 −4
Original line number Diff line number Diff line
@@ -1276,10 +1276,10 @@ static int __cpufreq_remove_dev_finish(struct device *dev, 
	unsigned long flags;

	struct cpufreq_policy *policy;



	read_lock_irqsave(&cpufreq_driver_lock, flags);

	write_lock_irqsave(&cpufreq_driver_lock, flags);

	policy = per_cpu(cpufreq_cpu_data, cpu);

	per_cpu(cpufreq_cpu_data, cpu) = NULL;

	read_unlock_irqrestore(&cpufreq_driver_lock, flags);

	write_unlock_irqrestore(&cpufreq_driver_lock, flags);



	if (!policy) {

		pr_debug("%s: No cpu_data found\n", __func__);
@@ -1445,12 +1445,17 @@ EXPORT_SYMBOL(cpufreq_quick_get_max); 


static unsigned int __cpufreq_get(unsigned int cpu)

{

	struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);

	struct cpufreq_policy *policy;

	unsigned int ret_freq = 0;

	unsigned long flags;



	if (!cpufreq_driver->get)

		return ret_freq;



	read_lock_irqsave(&cpufreq_driver_lock, flags);

	policy = per_cpu(cpufreq_cpu_data, cpu);

	read_unlock_irqrestore(&cpufreq_driver_lock, flags);



	ret_freq = cpufreq_driver->get(cpu);



	if (ret_freq && policy->cur &&
@@ -1474,12 +1479,17 @@ static unsigned int __cpufreq_get(unsigned int cpu) 
 */

unsigned int cpufreq_get(unsigned int cpu)

{

	struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);

	struct cpufreq_policy *policy;

	unsigned int ret_freq = 0;

	unsigned long flags;



	if (cpufreq_disabled() || !cpufreq_driver)

		return -ENOENT;



	read_lock_irqsave(&cpufreq_driver_lock, flags);

	policy = per_cpu(cpufreq_cpu_data, cpu);

	read_unlock_irqrestore(&cpufreq_driver_lock, flags);



	BUG_ON(!policy);



	if (!down_read_trylock(&cpufreq_rwsem))