From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shilpasri G Bhat Subject: [PATCH v7 2/6] cpufreq: powernv: Hot-plug safe the kworker thread Date: Thu, 28 Jan 2016 12:55:37 +0530 Message-ID: <1453965941-7363-3-git-send-email-shilpa.bhat@linux.vnet.ibm.com> References: <1453965941-7363-1-git-send-email-shilpa.bhat@linux.vnet.ibm.com> Return-path: In-Reply-To: <1453965941-7363-1-git-send-email-shilpa.bhat@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org To: linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org Cc: rjw@rjwysocki.net, viresh.kumar@linaro.org, linux-pm@vger.kernel.org, pc@us.ibm.com, anton@samba.org, ego@linux.vnet.ibm.com, shreyas@linux.vnet.ibm.com, bsingharora@gmail.com, mpe@ellerman.id.au, Shilpasri G Bhat List-Id: linux-pm@vger.kernel.org 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 --- No changes from v6. Changes form v5: - Fix the kbuild-error: drivers/cpufreq/powernv-cpufreq.c:428:2: error: implicit declaration of function 'get_online_cpus' [-Werror=implicit-function-declaration 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 53f980b..a271b0f 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] = { -- 1.9.3