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Commit 6e0e613f authored by Todd Poynor's avatar Todd Poynor Committed by Ruchi Kandoi
Browse files

cpufreq: interactive: fix deadlock on spinlock in timer 



Need to use irqsave/restore spinlock calls to avoid a deadlock in calls
from the timer.

Change-Id: I15b6b590045ba1447e34ca7b5ff342723e53a605
Signed-off-by: default avatarTodd Poynor <toddpoynor@google.com>
parent 67dd6bf3

drivers/cpufreq/cpufreq_interactive.c

+17 −12
Original line number Diff line number Diff line
@@ -126,6 +126,7 @@ static void cpufreq_interactive_timer_resched( 
	struct cpufreq_interactive_cpuinfo *pcpu)

{

	unsigned long expires = jiffies + usecs_to_jiffies(timer_rate);

	unsigned long flags;



	mod_timer_pinned(&pcpu->cpu_timer, expires);

	if (timer_slack_val >= 0 && pcpu->target_freq > pcpu->policy->min) {
@@ -133,27 +134,28 @@ static void cpufreq_interactive_timer_resched( 
		mod_timer_pinned(&pcpu->cpu_slack_timer, expires);

	}



	spin_lock(&pcpu->load_lock);

	spin_lock_irqsave(&pcpu->load_lock, flags);

	pcpu->time_in_idle =

		get_cpu_idle_time_us(smp_processor_id(),

				     &pcpu->time_in_idle_timestamp);

	pcpu->cputime_speedadj = 0;

	pcpu->cputime_speedadj_timestamp = pcpu->time_in_idle_timestamp;

	spin_unlock(&pcpu->load_lock);

	spin_unlock_irqrestore(&pcpu->load_lock, flags);

}



static unsigned int freq_to_targetload(unsigned int freq)

{

	int i;

	unsigned int ret;

	unsigned long flags;



	spin_lock(&target_loads_lock);

	spin_lock_irqsave(&target_loads_lock, flags);



	for (i = 0; i < ntarget_loads - 1 && freq >= target_loads[i+1]; i += 2)

		;



	ret = target_loads[i];

	spin_unlock(&target_loads_lock);

	spin_unlock_irqrestore(&target_loads_lock, flags);

	return ret;

}
@@ -284,11 +286,11 @@ static void cpufreq_interactive_timer(unsigned long data) 
	if (!pcpu->governor_enabled)

		goto exit;



	spin_lock(&pcpu->load_lock);

	spin_lock_irqsave(&pcpu->load_lock, flags);

	now = update_load(data);

	delta_time = (unsigned int)(now - pcpu->cputime_speedadj_timestamp);

	cputime_speedadj = pcpu->cputime_speedadj;

	spin_unlock(&pcpu->load_lock);

	spin_unlock_irqrestore(&pcpu->load_lock, flags);



	if (WARN_ON_ONCE(!delta_time))

		goto rearm;
@@ -549,6 +551,7 @@ static int cpufreq_interactive_notifier( 
	struct cpufreq_freqs *freq = data;

	struct cpufreq_interactive_cpuinfo *pcpu;

	int cpu;

	unsigned long flags;



	if (val == CPUFREQ_POSTCHANGE) {

		pcpu = &per_cpu(cpuinfo, freq->cpu);
@@ -562,9 +565,9 @@ static int cpufreq_interactive_notifier( 
		for_each_cpu(cpu, pcpu->policy->cpus) {

			struct cpufreq_interactive_cpuinfo *pjcpu =

				&per_cpu(cpuinfo, cpu);

			spin_lock(&pjcpu->load_lock);

			spin_lock_irqsave(&pjcpu->load_lock, flags);

			update_load(cpu);

			spin_unlock(&pjcpu->load_lock);

			spin_unlock_irqrestore(&pjcpu->load_lock, flags);

		}



		up_read(&pcpu->enable_sem);
@@ -581,15 +584,16 @@ static ssize_t show_target_loads( 
{

	int i;

	ssize_t ret = 0;

	unsigned long flags;



	spin_lock(&target_loads_lock);

	spin_lock_irqsave(&target_loads_lock, flags);



	for (i = 0; i < ntarget_loads; i++)

		ret += sprintf(buf + ret, "%u%s", target_loads[i],

			       i & 0x1 ? ":" : " ");



	ret += sprintf(buf + ret, "\n");

	spin_unlock(&target_loads_lock);

	spin_unlock_irqrestore(&target_loads_lock, flags);

	return ret;

}
@@ -602,6 +606,7 @@ static ssize_t store_target_loads( 
	unsigned int *new_target_loads = NULL;

	int ntokens = 1;

	int i;

	unsigned long flags;



	cp = buf;

	while ((cp = strpbrk(cp + 1, " :")))
@@ -631,12 +636,12 @@ static ssize_t store_target_loads( 
	if (i != ntokens)

		goto err_inval;



	spin_lock(&target_loads_lock);

	spin_lock_irqsave(&target_loads_lock, flags);

	if (target_loads != default_target_loads)

		kfree(target_loads);

	target_loads = new_target_loads;

	ntarget_loads = ntokens;

	spin_unlock(&target_loads_lock);

	spin_unlock_irqrestore(&target_loads_lock, flags);

	return count;



err_inval: