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>

1 files changed, 17 insertions, 12 deletions

diff --git a/drivers/cpufreq/cpufreq_interactive.c b/drivers/cpufreq/cpufreq_interactive.c
index 286781ff9dd..c70ebf53415 100644
--- 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: