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cpufreq: msm: fix race in cpufreq

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__cpufreq_driver_target expects to be called with the rw semaphore
held. We are not doing this when the frequency is asked to be changed
by dcvs.

Use cpufreq_driver_target variant of that function which gets the
rw semaphore before setting the frequency.

Change-Id: I67a7d437f68749f43c26b95ae73f436890326019
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
This commit is contained in:
Abhijeet Dharmapurikar 2012-08-26 20:33:43 -07:00 committed by Stephen Boyd
parent e2c08a46fc
commit e585b1137c
1 changed files with 14 additions and 5 deletions
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19
drivers/cpufreq/cpufreq_gov_msm.c
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@ -66,13 +66,17 @@ static int msm_dcvs_freq_set(struct msm_dcvs_freq *self,
if (freq > gov->max_freq)
freq = gov->max_freq;
ret = __cpufreq_driver_target(gov->policy, freq, CPUFREQ_RELATION_L);
gov->cur_freq = gov->policy->cur;
mutex_unlock(&per_cpu(gov_mutex, gov->cpu));
if (!ret)
return gov->cur_freq;
ret = cpufreq_driver_target(gov->policy, freq, CPUFREQ_RELATION_L);
if (!ret) {
gov->cur_freq = cpufreq_quick_get(gov->cpu);
if (freq != gov->cur_freq)
pr_err("cpu %d freq %u gov->cur_freq %u didn't match",
gov->cpu, freq, gov->cur_freq);
}
ret = gov->cur_freq;
return ret;
}
@ -82,6 +86,11 @@ static unsigned int msm_dcvs_freq_get(struct msm_dcvs_freq *self)
struct msm_gov *gov =
container_of(self, struct msm_gov, gov_notifier);
/*
* the rw_sem in cpufreq is always held when this is called.
* The policy->cur won't be updated in this case - so it is safe to
* access policy->cur
*/
return gov->cur_freq;
}