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: Todd Poynor <toddpoynor@google.com>

diff --git a/drivers/cpufreq/cpufreq_interactive.c b/drivers/cpufreq/cpufreq_interactive.c
index 286781ff9dd1cd4d3d887bd630a0fe968c2e5cb3..c70ebf534151da33c06186cbe22dce0f5decdc30 100644 (file)
--- a/drivers/cpufreq/cpufreq_interactive.c
+++ b/drivers/cpufreq/cpufreq_interactive.c
@@ -125,6 +125,7 @@ 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) {
@@ -132,27 +133,28 @@ 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;
 }
 
@@ -283,11 +285,11 @@ 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;
@@ -548,6 +550,7 @@ 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);
@@ -561,9 +564,9 @@ 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);
@@ -580,15 +583,16 @@ 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;
 }
 
@@ -601,6 +605,7 @@ 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, " :")))
@@ -630,12 +635,12 @@ 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: