cpufreq: governor: Use common mutex for dbs_data protection

Every governor relying on the common code in cpufreq_governor.c
has to provide its own mutex in struct common_dbs_data.  However,
there actually is no need to have a separate mutex per governor
for this purpose, they may be using the same global mutex just
fine.  Accordingly, introduce a single common mutex for that and
drop the mutex field from struct common_dbs_data.

That at least will ensure that the mutex is always present and
initialized regardless of what the particular governors do.

Another benefit is that the common code does not need a pointer to
a governor-related structure to get to the mutex which sometimes
helps.

Finally, it makes the code generally easier to follow.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Saravana Kannan <skannan@codeaurora.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

1 files changed, 5 insertions, 2 deletions

diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c
index 6bc2f50cc1d9..f291fdd878ce 100644
--- a/drivers/cpufreq/cpufreq_governor.c
+++ b/drivers/cpufreq/cpufreq_governor.c
@@ -22,6 +22,9 @@
 
 #include "cpufreq_governor.h"
 
+DEFINE_MUTEX(dbs_data_mutex);
+EXPORT_SYMBOL_GPL(dbs_data_mutex);
+
 static struct attribute_group *get_sysfs_attr(struct dbs_data *dbs_data)
 {
 	if (have_governor_per_policy())
@@ -543,7 +546,7 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 	int ret;
 
 	/* Lock governor to block concurrent initialization of governor */
-	mutex_lock(&cdata->mutex);
+	mutex_lock(&dbs_data_mutex);
 
 	if (have_governor_per_policy())
 		dbs_data = policy->governor_data;
@@ -576,7 +579,7 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 	}
 
 unlock:
-	mutex_unlock(&cdata->mutex);
+	mutex_unlock(&dbs_data_mutex);
 
 	return ret;
 }