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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2016-05-18 22:59:49 +0200
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2016-06-02 23:24:39 +0200
commit9a15fb2c797a15524e63eacb10bd6cd68a99e830 (patch)
treec42c85d19058a8632ce0a5fd06ae775d04ca654c /include/linux/cpufreq.h
parentbf2be2de8493dd5f86d6e0f0d4eecb5810ad035b (diff)
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cpufreq: Drop the 'initialized' field from struct cpufreq_governor
The 'initialized' field in struct cpufreq_governor is only used by the conservative governor (as a usage counter) and the way that happens is far from straightforward and arguably incorrect. Namely, the value of 'initialized' is checked by cpufreq_dbs_governor_init() and cpufreq_dbs_governor_exit() and the results of those checks are passed (as the second argument) to the ->init() and ->exit() callbacks in struct dbs_governor. Those callbacks are only implemented by the ondemand and conservative governors and ondemand doesn't use their second argument at all. In turn, the conservative governor uses it to decide whether or not to either register or unregister a transition notifier. That whole mechanism is not only unnecessarily convoluted, but also racy, because the 'initialized' field of struct cpufreq_governor is updated in cpufreq_init_governor() and cpufreq_exit_governor() under policy->rwsem which doesn't help if one of these functions is run twice in parallel for different policies (which isn't impossible in principle), for example. Instead of it, add a proper usage counter to the conservative governor and update it from cs_init() and cs_exit() which is guaranteed to be non-racy, as those functions are only called under gov_dbs_data_mutex which is global. With that in place, drop the 'initialized' field from struct cpufreq_governor as it is not used any more. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Diffstat (limited to 'include/linux/cpufreq.h')
-rw-r--r--include/linux/cpufreq.h1
1 files changed, 0 insertions, 1 deletions
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 3be54a0..fbd696e 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -457,7 +457,6 @@ static inline unsigned long cpufreq_scale(unsigned long old, u_int div,
struct cpufreq_governor {
char name[CPUFREQ_NAME_LEN];
- int initialized;
int (*init)(struct cpufreq_policy *policy);
void (*exit)(struct cpufreq_policy *policy);
int (*start)(struct cpufreq_policy *policy);
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