From 6d167a44e6c8da3316e037b788585fcf96112bea Mon Sep 17 00:00:00 2001 From: Shilpasri G Bhat Date: Wed, 3 Feb 2016 01:11:38 +0530 Subject: [PATCH] cpufreq: powernv: Hot-plug safe the kworker thread In the kworker_thread powernv_cpufreq_work_fn(), we can end up sending an IPI to a cpu going offline. This is a rare corner case which is fixed using {get/put}_online_cpus(). Along with this fix, this patch adds changes to do oneshot cpumask_{clear/and} operation. Suggested-by: Shreyas B Prabhu Suggested-by: Gautham R Shenoy Signed-off-by: Shilpasri G Bhat Reviewed-by: Gautham R. Shenoy Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/powernv-cpufreq.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c index 53f980bf9b77..a271b0fbe8b9 100644 --- a/drivers/cpufreq/powernv-cpufreq.c +++ b/drivers/cpufreq/powernv-cpufreq.c @@ -28,6 +28,7 @@ #include #include #include +#include #include #include @@ -423,18 +424,19 @@ void powernv_cpufreq_work_fn(struct work_struct *work) { struct chip *chip = container_of(work, struct chip, throttle); unsigned int cpu; - cpumask_var_t mask; + cpumask_t mask; - smp_call_function_any(&chip->mask, + get_online_cpus(); + cpumask_and(&mask, &chip->mask, cpu_online_mask); + smp_call_function_any(&mask, powernv_cpufreq_throttle_check, NULL, 0); if (!chip->restore) - return; + goto out; chip->restore = false; - cpumask_copy(mask, &chip->mask); - for_each_cpu_and(cpu, mask, cpu_online_mask) { - int index, tcpu; + for_each_cpu(cpu, &mask) { + int index; struct cpufreq_policy policy; cpufreq_get_policy(&policy, cpu); @@ -442,9 +444,10 @@ void powernv_cpufreq_work_fn(struct work_struct *work) policy.cur, CPUFREQ_RELATION_C, &index); powernv_cpufreq_target_index(&policy, index); - for_each_cpu(tcpu, policy.cpus) - cpumask_clear_cpu(tcpu, mask); + cpumask_andnot(&mask, &mask, policy.cpus); } +out: + put_online_cpus(); } static char throttle_reason[][30] = { -- 2.20.1