cpufreq: make sure frequency transitions are serialized
Whenever we are changing frequency of a cpu, we are calling PRECHANGE and
POSTCHANGE notifiers. They must be serialized. i.e. PRECHANGE or POSTCHANGE
shouldn't be called twice contiguously.
This can happen due to bugs in users of __cpufreq_driver_target() or actual
cpufreq drivers who are sending these notifiers.
This patch adds some protection against this. Now, we keep track of the last
transaction and see if something went wrong.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 3c7ee2f..c0bc737 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -119,6 +119,7 @@
struct kobject kobj;
struct completion kobj_unregister;
+ bool transition_ongoing; /* Tracks transition status */
};
#define CPUFREQ_ADJUST (0)