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| author | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2022-05-11 17:51:39 +0200 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2022-05-12 17:11:57 +0200 |
| commit | f339f3541701d824a0256ad4bf14c26ceb6d79c3 (patch) | |
| tree | 018563397be7130f81c61a13db0e456463461d46 /drivers/cpufreq | |
| parent | fddd8f86dff4a24742a7f0322ccbb34c6c1c9850 (diff) | |
| download | linux-f339f3541701d824a0256ad4bf14c26ceb6d79c3.tar.gz | |
cpufreq: Rearrange locking in cpufreq_remove_dev()
Currently, cpufreq_remove_dev() invokes the ->exit() driver callback without holding the policy rwsem which is inconsistent with what happens if ->exit() is invoked directly from cpufreq_offline(). It also manipulates the real_cpus mask and removes the CPU device symlink without holding the policy rwsem, but cpufreq_offline() holds the rwsem around the modifications thereof. For consistency, modify cpufreq_remove_dev() to hold the policy rwsem until the ->exit() callback has been called (or it has been determined that it is not necessary to call it). Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Diffstat (limited to 'drivers/cpufreq')
| -rw-r--r-- | drivers/cpufreq/cpufreq.c | 21 |
1 files changed, 14 insertions, 7 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 9664a86766c9..1f6667ce43bd 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1660,18 +1660,25 @@ static void cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif) if (!policy) return; + down_write(&policy->rwsem); + if (cpu_online(cpu)) - cpufreq_offline(cpu); + __cpufreq_offline(cpu, policy); remove_cpu_dev_symlink(policy, cpu, dev); - if (cpumask_empty(policy->real_cpus)) { - /* We did light-weight exit earlier, do full tear down now */ - if (cpufreq_driver->offline) - cpufreq_driver->exit(policy); - - cpufreq_policy_free(policy); + if (!cpumask_empty(policy->real_cpus)) { + up_write(&policy->rwsem); + return; } + + /* We did light-weight exit earlier, do full tear down now */ + if (cpufreq_driver->offline) + cpufreq_driver->exit(policy); + + up_write(&policy->rwsem); + + cpufreq_policy_free(policy); } /** |