cpufreq: Clear policy->cpus bits in __cpufreq_remove_dev_finish()

This broke after a recent change "cedb70a cpufreq: Split __cpufreq_remove_dev()
into two parts" from Srivatsa.

Consider a scenario where we have two CPUs in a policy (0 & 1) and we are
removing CPU 1. On the call to __cpufreq_remove_dev_prepare() we have cleared 1
from policy->cpus and now on a call to __cpufreq_remove_dev_finish() we read
cpumask_weight of policy->cpus, which will come as 1 and this code will behave
as if we are removing the last CPU from policy :)

Fix it by clearing the CPU mask in __cpufreq_remove_dev_finish() instead of
__cpufreq_remove_dev_prepare().

Tested-by: Stephen Warren <swarren@wwwdotorg.org>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 8 insertions, 8 deletions

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 43c24aa756f6..dbfe219667d3 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1125,7 +1125,7 @@ static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *policy,
         int ret;
 
         /* first sibling now owns the new sysfs dir */
-        cpu_dev = get_cpu_device(cpumask_first(policy->cpus));
+        cpu_dev = get_cpu_device(cpumask_any_but(policy->cpus, old_cpu));
 
         /* Don't touch sysfs files during light-weight tear-down */
         if (frozen)
@@ -1189,12 +1189,9 @@ static int __cpufreq_remove_dev_prepare(struct device *dev,
                         policy->governor->name, CPUFREQ_NAME_LEN);
 #endif
 
-        WARN_ON(lock_policy_rwsem_write(cpu));
+        lock_policy_rwsem_read(cpu);
         cpus = cpumask_weight(policy->cpus);
-
-        if (cpus > 1)
-                cpumask_clear_cpu(cpu, policy->cpus);
-        unlock_policy_rwsem_write(cpu);
+        unlock_policy_rwsem_read(cpu);
 
         if (cpu != policy->cpu) {
                 if (!frozen)
@@ -1237,9 +1234,12 @@ static int __cpufreq_remove_dev_finish(struct device *dev,
                 return -EINVAL;
         }
 
-        lock_policy_rwsem_read(cpu);
+        WARN_ON(lock_policy_rwsem_write(cpu));
         cpus = cpumask_weight(policy->cpus);
-        unlock_policy_rwsem_read(cpu);
+
+        if (cpus > 1)
+                cpumask_clear_cpu(cpu, policy->cpus);
+        unlock_policy_rwsem_write(cpu);
 
         /* If cpu is last user of policy, free policy */
         if (cpus == 1) {