Signed-off-by: Saravana Kannan <redacted>
---
 drivers/cpufreq/cpufreq.c | 46 +++++++++++++++++++++++++++++++++-------------
 1 file changed, 33 insertions(+), 13 deletions(-)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index d9fc6e5..97edf05 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c

@@ -41,6 +41,7 @@ static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data_fallback);
 static DEFINE_RWLOCK(cpufreq_driver_lock);
 DEFINE_MUTEX(cpufreq_governor_lock);
 static LIST_HEAD(cpufreq_policy_list);
+static cpumask_t has_symlink;

 /* This one keeps track of the previously set governor of a removed CPU */
 static DEFINE_PER_CPU(char[CPUFREQ_NAME_LEN], cpufreq_cpu_governor);

@@ -865,7 +866,10 @@ static int cpufreq_add_dev_symlink(struct cpufreq_policy *policy)
        unsigned int j;
        int ret = 0;

-       for_each_cpu(j, policy->related_cpus) {
+       /* Only some of the related CPUs might be present. So, create
+        * symlinks only for those.
+        */

+       for_each_cpu_and(j, policy->related_cpus, cpu_present_mask) {
                struct device *cpu_dev;

                if (j == policy->kobj_cpu)

@@ -877,6 +881,7 @@ static int cpufreq_add_dev_symlink(struct cpufreq_policy *policy)
                                        "cpufreq");
                if (ret)
                        break;
+               cpumask_set_cpu(j, &has_symlink);
        }
        return ret;
 }

@@ -1101,9 +1106,6 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
        unsigned long flags;
        bool recover_policy = cpufreq_suspended;

-       if (cpu_is_offline(cpu))
-               return 0;
-

        pr_debug("adding CPU %u\n", cpu);

 #ifdef CONFIG_SMP

@@ -1111,7 +1113,19 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
         * CPU because it is in the same boat. */
        policy = cpufreq_cpu_get(cpu);
        if (policy) {
-               if (!cpumask_test_cpu(cpu, policy->cpus))
+               /* If a CPU gets physically plugged in after one or more of
+                * its related CPUs are ONLINE, we need to create a symlink
+                * for it since it wouldn't have been created when the policy
+                * was initialized. Do this as soon as it's plugged in.
+                */
+               if (sif && !cpumask_test_cpu(cpu, &has_symlink)) {

+               if (!cpumask_test_cpu(cpu, policy->cpus) && cpu_online(cpu))
                        ret = cpufreq_add_policy_cpu(policy, cpu, dev);
                else
                        ret = 0;

@@ -1120,6 +1134,9 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
        }
 #endif

+       if (cpu_is_offline(cpu))
+               return 0;
+

        if (!down_read_trylock(&cpufreq_rwsem))
                return 0;

@@ -1303,25 +1320,24 @@ static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *policy,
                                           unsigned int old_cpu)
 {
        struct device *cpu_dev;
+       unsigned int new_cpu;
        int ret;

        /* first sibling now owns the new sysfs dir */
-       cpu_dev = get_cpu_device(cpumask_any_but(policy->cpus, old_cpu));
+       for_each_cpu_and(new_cpu, policy->related_cpus, cpu_present_mask)
+               if (new_cpu != old_cpu)
+                       break;
+       cpu_dev = get_cpu_device(new_cpu);

        sysfs_remove_link(&cpu_dev->kobj, "cpufreq");
        ret = kobject_move(&policy->kobj, &cpu_dev->kobj);
        if (ret) {
                pr_err("%s: Failed to move kobj: %d\n", __func__, ret);
-
-               down_write(&policy->rwsem);
-               cpumask_set_cpu(old_cpu, policy->cpus);
-               up_write(&policy->rwsem);
-
                ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj,
                                        "cpufreq");
-
                return -EINVAL;
        }
+       cpumask_clear_cpu(new_cpu, &has_symlink);
        policy->kobj_cpu = cpu_dev->id;

        return cpu_dev->id;

@@ -1407,8 +1423,12 @@ static int __cpufreq_remove_dev_finish(struct device *dev,
        cpus = cpumask_weight(policy->cpus);
        up_read(&policy->rwsem);

-       if (cpu != policy->kobj_cpu)
+       if (cpu != policy->kobj_cpu) {
                sysfs_remove_link(&dev->kobj, "cpufreq");
+               cpumask_clear_cpu(cpu, &has_symlink);
+       } else {
+               cpufreq_nominate_new_policy_cpu(policy, cpu);
+       }