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Subject[PATCH v2 4/7] cpufreq: Extract the handover of policy cpu to a helper function
Date
During cpu offline, when the policy->cpu is going down, some other CPU
present in the policy->cpus mask is nominated as the new policy->cpu.
Extract this functionality from __cpufreq_remove_dev() and implement
it in a helper function. This helps in upcoming code reorganization.

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
---

drivers/cpufreq/cpufreq.c | 63 ++++++++++++++++++++++++++++-----------------
1 file changed, 39 insertions(+), 24 deletions(-)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 39bda8f..32b3ce7 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1129,6 +1129,38 @@ static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
CPUFREQ_UPDATE_POLICY_CPU, policy);
}

+static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *data,
+ unsigned int old_cpu)
+{
+ struct device *cpu_dev;
+ unsigned long flags;
+ int ret;
+
+ /* first sibling now owns the new sysfs dir */
+ cpu_dev = get_cpu_device(cpumask_first(data->cpus));
+ sysfs_remove_link(&cpu_dev->kobj, "cpufreq");
+ ret = kobject_move(&data->kobj, &cpu_dev->kobj);
+ if (ret) {
+ pr_err("%s: Failed to move kobj: %d", __func__, ret);
+
+ WARN_ON(lock_policy_rwsem_write(old_cpu));
+ cpumask_set_cpu(old_cpu, data->cpus);
+
+ write_lock_irqsave(&cpufreq_driver_lock, flags);
+ per_cpu(cpufreq_cpu_data, old_cpu) = data;
+ write_unlock_irqrestore(&cpufreq_driver_lock, flags);
+
+ unlock_policy_rwsem_write(old_cpu);
+
+ ret = sysfs_create_link(&cpu_dev->kobj, &data->kobj,
+ "cpufreq");
+
+ return -EINVAL;
+ }
+
+ return cpu_dev->id;
+}
+
/**
* __cpufreq_remove_dev - remove a CPU device
*
@@ -1139,12 +1171,12 @@ static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
static int __cpufreq_remove_dev(struct device *dev,
struct subsys_interface *sif)
{
- unsigned int cpu = dev->id, ret, cpus;
+ unsigned int cpu = dev->id, cpus;
+ int new_cpu;
unsigned long flags;
struct cpufreq_policy *data;
struct kobject *kobj;
struct completion *cmp;
- struct device *cpu_dev;

pr_debug("%s: unregistering CPU %u\n", __func__, cpu);

@@ -1179,32 +1211,15 @@ static int __cpufreq_remove_dev(struct device *dev,
if (cpu != data->cpu) {
sysfs_remove_link(&dev->kobj, "cpufreq");
} else if (cpus > 1) {
- /* first sibling now owns the new sysfs dir */
- cpu_dev = get_cpu_device(cpumask_first(data->cpus));
- sysfs_remove_link(&cpu_dev->kobj, "cpufreq");
- ret = kobject_move(&data->kobj, &cpu_dev->kobj);
- if (ret) {
- pr_err("%s: Failed to move kobj: %d", __func__, ret);

+ new_cpu = cpufreq_nominate_new_policy_cpu(data, cpu);
+ if (new_cpu >= 0) {
WARN_ON(lock_policy_rwsem_write(cpu));
- cpumask_set_cpu(cpu, data->cpus);
-
- write_lock_irqsave(&cpufreq_driver_lock, flags);
- per_cpu(cpufreq_cpu_data, cpu) = data;
- write_unlock_irqrestore(&cpufreq_driver_lock, flags);
-
+ update_policy_cpu(data, new_cpu);
unlock_policy_rwsem_write(cpu);
-
- ret = sysfs_create_link(&cpu_dev->kobj, &data->kobj,
- "cpufreq");
- return -EINVAL;
+ pr_debug("%s: policy Kobject moved to cpu: %d "
+ "from: %d\n",__func__, new_cpu, cpu);
}
-
- WARN_ON(lock_policy_rwsem_write(cpu));
- update_policy_cpu(data, cpu_dev->id);
- unlock_policy_rwsem_write(cpu);
- pr_debug("%s: policy Kobject moved to cpu: %d from: %d\n",
- __func__, cpu_dev->id, cpu);
}

/* If cpu is last user of policy, free policy */


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