diff options
| author | Viresh Kumar <viresh.kumar@linaro.org> | 2016-02-11 17:31:13 +0530 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2016-03-09 14:41:01 +0100 |
| commit | 99522fe6788f5bf627dce7c20ed9484c933511a3 (patch) | |
| tree | 55353e0c03780e911cf855135f32f02565fd9603 /drivers/cpufreq/cpufreq.c | |
| parent | 49f18560f8bac5315047edfb673dd13d56cbcbc9 (diff) | |
| download | linux-99522fe6788f5bf627dce7c20ed9484c933511a3.tar.gz linux-99522fe6788f5bf627dce7c20ed9484c933511a3.tar.bz2 linux-99522fe6788f5bf627dce7c20ed9484c933511a3.zip | |
cpufreq: Remove cpufreq_governor_lock
We used to drop policy->rwsem just before calling __cpufreq_governor()
in some cases earlier and so it was possible that __cpufreq_governor()
ran concurrently via separate threads for the same policy.
In order to guarantee valid state transitions for governors,
'governor_enabled' was required to be protected using some locking
and cpufreq_governor_lock was added for that.
But now __cpufreq_governor() is always called under policy->rwsem,
and 'governor_enabled' is protected against races even without
cpufreq_governor_lock.
Get rid of the extra lock now.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Juri Lelli <juri.lelli@arm.com>
Tested-by: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
[ rjw : Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpufreq/cpufreq.c')
| -rw-r--r-- | drivers/cpufreq/cpufreq.c | 8 |
1 files changed, 0 insertions, 8 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 692876892457..bc93272b4a12 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -147,8 +147,6 @@ void cpufreq_update_util(u64 time, unsigned long util, unsigned long max) rcu_read_unlock(); } -DEFINE_MUTEX(cpufreq_governor_lock); - /* Flag to suspend/resume CPUFreq governors */ static bool cpufreq_suspended; @@ -2015,11 +2013,9 @@ static int __cpufreq_governor(struct cpufreq_policy *policy, pr_debug("%s: for CPU %u, event %u\n", __func__, policy->cpu, event); - mutex_lock(&cpufreq_governor_lock); if ((policy->governor_enabled && event == CPUFREQ_GOV_START) || (!policy->governor_enabled && (event == CPUFREQ_GOV_LIMITS || event == CPUFREQ_GOV_STOP))) { - mutex_unlock(&cpufreq_governor_lock); return -EBUSY; } @@ -2028,8 +2024,6 @@ static int __cpufreq_governor(struct cpufreq_policy *policy, else if (event == CPUFREQ_GOV_START) policy->governor_enabled = true; - mutex_unlock(&cpufreq_governor_lock); - ret = policy->governor->governor(policy, event); if (!ret) { @@ -2039,12 +2033,10 @@ static int __cpufreq_governor(struct cpufreq_policy *policy, policy->governor->initialized--; } else { /* Restore original values */ - mutex_lock(&cpufreq_governor_lock); if (event == CPUFREQ_GOV_STOP) policy->governor_enabled = true; else if (event == CPUFREQ_GOV_START) policy->governor_enabled = false; - mutex_unlock(&cpufreq_governor_lock); } if (((event == CPUFREQ_GOV_POLICY_INIT) && ret) || |