Commit 11e584cf authored by Viresh Kumar's avatar Viresh Kumar Committed by Rafael J. Wysocki

cpufreq: Don't allow updating inactive policies from sysfs

Later commits would change the way policies are managed today. Policies
wouldn't be freed on cpu hotplug (currently they aren't freed only for
suspend), and while the CPU is offline, the sysfs cpufreq files would
still be present.

User may accidentally try to update the sysfs files in following
directory: '/sys/devices/system/cpu/cpuX/cpufreq/'. And that would
result in undefined behavior as policy wouldn't be active then.

Apart from updating the store() routine, we also update __cpufreq_get()
which can call cpufreq_out_of_sync(). The later routine tries to update
policy->cur and starts notifying kernel about it.
Signed-off-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Acked-by: default avatarSaravana Kannan <skannan@codeaurora.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 6c1e4591
...@@ -875,11 +875,18 @@ static ssize_t store(struct kobject *kobj, struct attribute *attr, ...@@ -875,11 +875,18 @@ static ssize_t store(struct kobject *kobj, struct attribute *attr,
down_write(&policy->rwsem); down_write(&policy->rwsem);
/* Updating inactive policies is invalid, so avoid doing that. */
if (unlikely(policy_is_inactive(policy))) {
ret = -EBUSY;
goto unlock_policy_rwsem;
}
if (fattr->store) if (fattr->store)
ret = fattr->store(policy, buf, count); ret = fattr->store(policy, buf, count);
else else
ret = -EIO; ret = -EIO;
unlock_policy_rwsem:
up_write(&policy->rwsem); up_write(&policy->rwsem);
up_read(&cpufreq_rwsem); up_read(&cpufreq_rwsem);
...@@ -1610,6 +1617,10 @@ static unsigned int __cpufreq_get(struct cpufreq_policy *policy) ...@@ -1610,6 +1617,10 @@ static unsigned int __cpufreq_get(struct cpufreq_policy *policy)
ret_freq = cpufreq_driver->get(policy->cpu); ret_freq = cpufreq_driver->get(policy->cpu);
/* Updating inactive policies is invalid, so avoid doing that. */
if (unlikely(policy_is_inactive(policy)))
return ret_freq;
if (ret_freq && policy->cur && if (ret_freq && policy->cur &&
!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) { !(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
/* verify no discrepancy between actual and /* verify no discrepancy between actual and
......
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