cpufreq: userspace: Move is_managed indicator into per-policy structure

The userspace governor uses the 'cpu' field of cpufreq_policy structure
to track if it is allowed to set the speed of the policy.

However, there is a window where the 'cpu' field is equal to the value
of nr_cpus_id when all affected CPUs of policy are offline, which is an
illegal value to get the per-CPU variable.

To avoid this issue, modify the governor to use a per-policy indicator
to track if the policy is managed.

Signed-off-by: Liao Chang <liaochang1@huawei.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/cpufreq/cpufreq_userspace.c b/drivers/cpufreq/cpufreq_userspace.c
index 442e31060d6275efbffea654bc9d053c9b922c59..2c42fee76daa808f0cd1c7b1ab85476e695082e9 100644 (file)
--- a/drivers/cpufreq/cpufreq_userspace.c
+++ b/drivers/cpufreq/cpufreq_userspace.c
@@ -15,9 +15,8 @@
 #include <linux/mutex.h>
 #include <linux/slab.h>
 
-static DEFINE_PER_CPU(unsigned int, cpu_is_managed);
-
 struct userspace_policy {
+       unsigned int is_managed;
        unsigned int setspeed;
        struct mutex mutex;
 };
@@ -37,7 +36,7 @@ static int cpufreq_set(struct cpufreq_policy *policy, unsigned int freq)
        pr_debug("cpufreq_set for cpu %u, freq %u kHz\n", policy->cpu, freq);
 
        mutex_lock(&userspace->mutex);
-       if (!per_cpu(cpu_is_managed, policy->cpu))
+       if (!userspace->is_managed)
                goto err;
 
        userspace->setspeed = freq;
@@ -85,7 +84,7 @@ static int cpufreq_userspace_policy_start(struct cpufreq_policy *policy)
        pr_debug("started managing cpu %u\n", policy->cpu);
 
        mutex_lock(&userspace->mutex);
-       per_cpu(cpu_is_managed, policy->cpu) = 1;
+       userspace->is_managed = 1;
        userspace->setspeed = policy->cur;
        mutex_unlock(&userspace->mutex);
        return 0;
@@ -98,7 +97,7 @@ static void cpufreq_userspace_policy_stop(struct cpufreq_policy *policy)
        pr_debug("managing cpu %u stopped\n", policy->cpu);
 
        mutex_lock(&userspace->mutex);
-       per_cpu(cpu_is_managed, policy->cpu) = 0;
+       userspace->is_managed = 0;
        userspace->setspeed = 0;
        mutex_unlock(&userspace->mutex);
 }