Return codes aren't honored properly in cpufreq_set_policy(). This can lead to two problems: - wrong errors propagated to sysfs - we try to do next state-change even if the previous one failed
cpufreq_governor_dbs() now returns proper errors on all invalid state-transition requests and this code should honor that.
Reviewed-and-tested-by: Preeti U Murthy preeti@linux.vnet.ibm.com Signed-off-by: Viresh Kumar viresh.kumar@linaro.org --- drivers/cpufreq/cpufreq.c | 31 ++++++++++++++++++++++++------- 1 file changed, 24 insertions(+), 7 deletions(-)
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index a7b6ac6e048e..a3e8fb61cbcc 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -2295,16 +2295,31 @@ static int cpufreq_set_policy(struct cpufreq_policy *policy, old_gov = policy->governor; /* end old governor */ if (old_gov) { - __cpufreq_governor(policy, CPUFREQ_GOV_STOP); + ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP); + if (ret) { + /* This can happen due to race with other operations */ + pr_debug("%s: Failed to Stop Governor: %s (%d)\n", + __func__, old_gov->name, ret); + return ret; + } + up_write(&policy->rwsem); - __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT); + ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT); down_write(&policy->rwsem); + + if (ret) { + pr_err("%s: Failed to Exit Governor: %s (%d)\n", + __func__, old_gov->name, ret); + return ret; + } }
/* start new governor */ policy->governor = new_policy->governor; - if (!__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT)) { - if (!__cpufreq_governor(policy, CPUFREQ_GOV_START)) + ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT); + if (!ret) { + ret = __cpufreq_governor(policy, CPUFREQ_GOV_START); + if (!ret) goto out;
up_write(&policy->rwsem); @@ -2316,11 +2331,13 @@ static int cpufreq_set_policy(struct cpufreq_policy *policy, pr_debug("starting governor %s failed\n", policy->governor->name); if (old_gov) { policy->governor = old_gov; - __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT); - __cpufreq_governor(policy, CPUFREQ_GOV_START); + if (__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT)) + policy->governor = NULL; + else + __cpufreq_governor(policy, CPUFREQ_GOV_START); }
- return -EINVAL; + return ret;
out: pr_debug("governor: change or update limits\n");