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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 <shreyas@linux.vnet.ibm.com>
Suggested-by: Gautham R Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Shilpasri G Bhat 2016-02-03 01:11:38 +05:30 committed by Rafael J. Wysocki
parent 86622cb8c5
commit 6d167a44e6
1 changed files with 11 additions and 8 deletions
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19
drivers/cpufreq/powernv-cpufreq.c
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@ -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] = {