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Commit 6d167a44 authored by Shilpasri G Bhat's avatar Shilpasri G Bhat Committed by Rafael J. Wysocki
Browse files

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: default avatarShreyas B Prabhu <shreyas@linux.vnet.ibm.com>
Suggested-by: default avatarGautham R Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: default avatarShilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
Reviewed-by: default avatarGautham R. Shenoy <ego@linux.vnet.ibm.com>
Acked-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 86622cb8

drivers/cpufreq/powernv-cpufreq.c

+11 −8
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ 
#include <linux/of.h>

#include <linux/reboot.h>

#include <linux/slab.h>

#include <linux/cpu.h>



#include <asm/cputhreads.h>

#include <asm/firmware.h>
@@ -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] = {