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cpufreq: Split __cpufreq_remove_dev() into two parts 

During CPU offline, the cpufreq core invokes __cpufreq_remove_dev()
to perform work such as stopping the cpufreq governor, clearing the
CPU from the policy structure etc, and finally cleaning up the
kobject.

There are certain subtle issues related to the kobject cleanup, and
it would be much easier to deal with them if we separate that part
from the rest of the cleanup-work in the CPU offline phase. So split
the __cpufreq_remove_dev() function into 2 parts: one that handles
the kobject cleanup, and the other that handles the rest of the work.

Reported-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Srivatsa S. Bhat 2013-09-07 01:23:09 +05:30 committed by Rafael J. Wysocki
parent a857c0b9e2
commit cedb70afd0
1 changed files with 53 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

65
drivers/cpufreq/cpufreq.c
View File

@ -1141,22 +1141,14 @@ static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *policy,
return cpu_dev->id;
}
/**
* __cpufreq_remove_dev - remove a CPU device
*
* Removes the cpufreq interface for a CPU device.
* Caller should already have policy_rwsem in write mode for this CPU.
* This routine frees the rwsem before returning.
*/
static int __cpufreq_remove_dev(struct device *dev,
struct subsys_interface *sif, bool frozen)
static int __cpufreq_remove_dev_prepare(struct device *dev,
struct subsys_interface *sif,
bool frozen)
{
unsigned int cpu = dev->id, cpus;
int new_cpu, ret;
unsigned long flags;
struct cpufreq_policy *policy;
struct kobject *kobj;
struct completion *cmp;
pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
@ -1213,6 +1205,33 @@ static int __cpufreq_remove_dev(struct device *dev,
}
}
return 0;
}
static int __cpufreq_remove_dev_finish(struct device *dev,
struct subsys_interface *sif,
bool frozen)
{
unsigned int cpu = dev->id, cpus;
int ret;
unsigned long flags;
struct cpufreq_policy *policy;
struct kobject *kobj;
struct completion *cmp;
read_lock_irqsave(&cpufreq_driver_lock, flags);
policy = per_cpu(cpufreq_cpu_data, cpu);
read_unlock_irqrestore(&cpufreq_driver_lock, flags);
if (!policy) {
pr_debug("%s: No cpu_data found\n", __func__);
return -EINVAL;
}
lock_policy_rwsem_read(cpu);
cpus = cpumask_weight(policy->cpus);
unlock_policy_rwsem_read(cpu);
/* If cpu is last user of policy, free policy */
if (cpus == 1) {
if (cpufreq_driver->target) {
@ -1272,6 +1291,27 @@ static int __cpufreq_remove_dev(struct device *dev,
return 0;
}
/**
* __cpufreq_remove_dev - remove a CPU device
*
* Removes the cpufreq interface for a CPU device.
* Caller should already have policy_rwsem in write mode for this CPU.
* This routine frees the rwsem before returning.
*/
static inline int __cpufreq_remove_dev(struct device *dev,
struct subsys_interface *sif,
bool frozen)
{
int ret;
ret = __cpufreq_remove_dev_prepare(dev, sif, frozen);
if (!ret)
ret = __cpufreq_remove_dev_finish(dev, sif, frozen);
return ret;
}
static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
{
unsigned int cpu = dev->id;
@ -2000,7 +2040,8 @@ static int cpufreq_cpu_callback(struct notifier_block *nfb,
break;
case CPU_DOWN_PREPARE:
__cpufreq_remove_dev(dev, NULL, frozen);
__cpufreq_remove_dev_prepare(dev, NULL, frozen);
__cpufreq_remove_dev_finish(dev, NULL, frozen);
break;
case CPU_DOWN_FAILED: