Governor sysfs attributes are still removed in __cpufreq_governor(_EXIT), though, so had store() been used for them, the deadlock described in the changelog of commit 1aee40ac9c86 would have been possible.
Fortunately, we don't use store() (which still does get_online_cpus()) for those attributes now. We use governor_store() for them and that doesn't call get_online_cpus().
And so we don't need to split cpufreq-offline functionality into DOWN_PREPARE and POST_DEAD hotplug notifiers anymore.
Signed-off-by: Viresh Kumar viresh.kumar@linaro.org [ rjw: Changelog ] Tested-by: Juri Lelli juri.lelli@arm.com Tested-by: Shilpasri G Bhat shilpa.bhat@linux.vnet.ibm.com --- drivers/cpufreq/cpufreq.c | 36 ++++++++++-------------------------- 1 file changed, 10 insertions(+), 26 deletions(-)
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 9c62bf35b9dc..863ac26c4ecf 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1361,9 +1361,10 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) return ret; }
-static void cpufreq_offline_prepare(unsigned int cpu) +static void cpufreq_offline(unsigned int cpu) { struct cpufreq_policy *policy; + int ret;
pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
@@ -1374,7 +1375,7 @@ static void cpufreq_offline_prepare(unsigned int cpu) }
if (has_target()) { - int ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP); + ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP); if (ret) pr_err("%s: Failed to stop governor\n", __func__); } @@ -1397,34 +1398,23 @@ static void cpufreq_offline_prepare(unsigned int cpu) /* Start governor again for active policy */ if (!policy_is_inactive(policy)) { if (has_target()) { - int ret = __cpufreq_governor(policy, CPUFREQ_GOV_START); + ret = __cpufreq_governor(policy, CPUFREQ_GOV_START); if (!ret) ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
if (ret) pr_err("%s: Failed to start governor\n", __func__); } - } else if (cpufreq_driver->stop_cpu) { - cpufreq_driver->stop_cpu(policy); - } -}
-static void cpufreq_offline_finish(unsigned int cpu) -{ - struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu); - - if (!policy) { - pr_debug("%s: No cpu_data found\n", __func__); return; }
- /* Only proceed for inactive policies */ - if (!policy_is_inactive(policy)) - return; + if (cpufreq_driver->stop_cpu) + cpufreq_driver->stop_cpu(policy);
/* If cpu is last user of policy, free policy */ if (has_target()) { - int ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT); + ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT); if (ret) pr_err("%s: Failed to exit governor\n", __func__); } @@ -1453,10 +1443,8 @@ static void cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif) if (!policy) return;
- if (cpu_online(cpu)) { - cpufreq_offline_prepare(cpu); - cpufreq_offline_finish(cpu); - } + if (cpu_online(cpu)) + cpufreq_offline(cpu);
cpumask_clear_cpu(cpu, policy->real_cpus); remove_cpu_dev_symlink(policy, cpu); @@ -2304,11 +2292,7 @@ static int cpufreq_cpu_callback(struct notifier_block *nfb, break;
case CPU_DOWN_PREPARE: - cpufreq_offline_prepare(cpu); - break; - - case CPU_POST_DEAD: - cpufreq_offline_finish(cpu); + cpufreq_offline(cpu); break;
case CPU_DOWN_FAILED: