From 69cee7147b4a4ea02085d571cd2d9974d4a4d8d5 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Thu, 11 Feb 2016 17:31:11 +0530 Subject: [PATCH] cpufreq: Merge cpufreq_offline_prepare/finish routines Commit 1aee40ac9c86 (cpufreq: Invoke __cpufreq_remove_dev_finish() after releasing cpu_hotplug.lock) split the cpufreq's CPU offline routine in two pieces, one of them to be run with CPU offline/online locked and the other to be called later. The reason for that split was a possible deadlock scenario involving cpufreq sysfs attributes and CPU offline. However, the handling of CPU offline in cpufreq has changed since then. Policy sysfs attributes are never removed during CPU offline, so there's no need to worry about accessing them during CPU offline, because that can't lead to any deadlocks now. Governor sysfs attributes are still removed in __cpufreq_governor(_EXIT), but there is a new kobject type for them now and its show/store callbacks don't lock CPU offline/online (they don't need to do that). This means that the CPU offline code in cpufreq doesn't need to be split any more, so combine cpufreq_offline_prepare() with cpufreq_offline_finish(). Signed-off-by: Viresh Kumar [ rjw: Changelog ] Tested-by: Juri Lelli Tested-by: Shilpasri G Bhat Signed-off-by: Rafael J. Wysocki --- 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 e92e9eab7c6c..f65553dc48c9 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1362,9 +1362,10 @@ 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); @@ -1375,7 +1376,7 @@ 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__); } @@ -1398,34 +1399,23 @@ 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__); } @@ -1454,10 +1444,8 @@ 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); @@ -2305,11 +2293,7 @@ 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: -- 2.20.1