On Friday, January 02, 2015 11:16:49 AM Viresh Kumar wrote:
Later commit will allocate memory from within the spinlock as that would be part of critical region. kzalloc() might sleep and we can't sleep from inside spinlocks critical region, so convert the spinlock into a mutex.
"We will need to allocate memory under cpufreq_stats_lock, so it cannot be a spinlock any more. Convert it to a mutex."
Reviewed-by: Prarit Bhargava prarit@redhat.com Signed-off-by: Viresh Kumar viresh.kumar@linaro.org
drivers/cpufreq/cpufreq_stats.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c index 7701532b32c8..de55ca86b6f1 100644 --- a/drivers/cpufreq/cpufreq_stats.c +++ b/drivers/cpufreq/cpufreq_stats.c @@ -12,10 +12,11 @@ #include <linux/cpu.h> #include <linux/cpufreq.h> #include <linux/module.h> +#include <linux/mutex.h> #include <linux/slab.h> #include <linux/cputime.h> -static spinlock_t cpufreq_stats_lock; +static DEFINE_MUTEX(cpufreq_stats_lock); struct cpufreq_stats { unsigned int total_trans; @@ -39,12 +40,12 @@ static int cpufreq_stats_update(struct cpufreq_stats *stat) { unsigned long long cur_time = get_jiffies_64();
- spin_lock(&cpufreq_stats_lock);
- mutex_lock(&cpufreq_stats_lock); if (stat->time_in_state) stat->time_in_state[stat->last_index] += cur_time - stat->last_time; stat->last_time = cur_time;
- spin_unlock(&cpufreq_stats_lock);
- mutex_unlock(&cpufreq_stats_lock); return 0;
} @@ -218,10 +219,10 @@ static int __cpufreq_stats_create_table(struct cpufreq_policy *policy) stat->freq_table[i++] = pos->frequency; stat->state_num = i;
- spin_lock(&cpufreq_stats_lock);
- mutex_lock(&cpufreq_stats_lock); stat->last_time = get_jiffies_64(); stat->last_index = freq_table_get_index(stat, policy->cur);
- spin_unlock(&cpufreq_stats_lock);
- mutex_unlock(&cpufreq_stats_lock);
policy->stats_data = stat; ret = sysfs_create_group(&policy->kobj, &stats_attr_group); @@ -298,13 +299,13 @@ static int cpufreq_stat_notifier_trans(struct notifier_block *nb, cpufreq_stats_update(stat);
- spin_lock(&cpufreq_stats_lock);
- mutex_lock(&cpufreq_stats_lock); stat->last_index = new_index;
#ifdef CONFIG_CPU_FREQ_STAT_DETAILS stat->trans_table[old_index * stat->max_state + new_index]++; #endif stat->total_trans++;
- spin_unlock(&cpufreq_stats_lock);
- mutex_unlock(&cpufreq_stats_lock); cpufreq_cpu_put(policy); return 0;
} @@ -322,7 +323,6 @@ static int __init cpufreq_stats_init(void) int ret; unsigned int cpu;
- spin_lock_init(&cpufreq_stats_lock); ret = cpufreq_register_notifier(¬ifier_policy_block, CPUFREQ_POLICY_NOTIFIER); if (ret)