Users of freq table may want to access it for any CPU from policy->related_cpus mask. One such user is cpu-cooling layer. It gets a list of 'clip_cpus' (equivalent to policy->related_cpus) during registration and tries to get freq_table for the first CPU of this mask.

If the CPU, for which it tries to fetch freq_table, is offline, cpufreq_frequency_get_table() fails. This happens because it relies on cpufreq_cpu_get_raw() for its functioning which returns policy only for online CPUs.

Fix this by considering offline CPUs, but with a restriction that the policy is active at that time.

Because we will be using 'cpufreq_cpu_data' now, which is internal to cpufreq-core, lets also move cpufreq_frequency_get_table() to cpufreq.c file.

Reported-and-tested-by: Pi-Cheng Chen pi-cheng.chen@linaro.org Signed-off-by: Viresh Kumar viresh.kumar@linaro.org --- V2: Get rid of cpufreq_cpu_data()'s declaration as well.. Thanks Javi.

drivers/cpufreq/cpufreq.c | 9 +++++++++ drivers/cpufreq/freq_table.c | 9 --------- 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 2c22e3902e72..26063afb3eba 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -169,6 +169,15 @@ struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy) } EXPORT_SYMBOL_GPL(get_governor_parent_kobj);

+struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned int cpu) +{ + struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu); + + return policy && !policy_is_inactive(policy) ? + policy->freq_table : NULL; +} +EXPORT_SYMBOL_GPL(cpufreq_frequency_get_table); + static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall) { u64 idle_time; diff --git a/drivers/cpufreq/freq_table.c b/drivers/cpufreq/freq_table.c index df14766a8e06..dfbbf981ed56 100644 --- a/drivers/cpufreq/freq_table.c +++ b/drivers/cpufreq/freq_table.c @@ -297,15 +297,6 @@ int cpufreq_table_validate_and_show(struct cpufreq_policy *policy, } EXPORT_SYMBOL_GPL(cpufreq_table_validate_and_show);

-struct cpufreq_policy *cpufreq_cpu_get_raw(unsigned int cpu); - -struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned int cpu) -{ - struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu); - return policy ? policy->freq_table : NULL; -} -EXPORT_SYMBOL_GPL(cpufreq_frequency_get_table); - MODULE_AUTHOR("Dominik Brodowski linux@brodo.de"); MODULE_DESCRIPTION("CPUfreq frequency table helpers"); MODULE_LICENSE("GPL");

On 09-07-15, 02:40, Rafael J. Wysocki wrote:

The above sentence is completely unclear to anyone unfamiliar with the code in question.

The fix is to access the policy data structure for the given CPU directly (which also returns a valid policy for offline CPUs), but the policy itself has to be active (meaning that at least one CPU using it is online) for the frequency table to be returned.

Right?

Yeah..

-------------------8<-------------------- Message-Id: 9c37b9a711b6dc6e419e256fd62fcc93a29db4e4.1436418686.git.viresh.kumar@linaro.org From: Viresh Kumar viresh.kumar@linaro.org Date: Wed, 8 Jul 2015 12:53:03 +0530 Subject: [PATCH V3] cpufreq: Allow accessing freq_table for offline CPUs

Users of freq table may want to access it for any CPU from policy->related_cpus mask. One such user is cpu-cooling layer. It gets a list of 'clip_cpus' (equivalent to policy->related_cpus) during registration and tries to get freq_table for the first CPU of this mask.

If the CPU, for which it tries to fetch freq_table, is offline, cpufreq_frequency_get_table() fails. This happens because it relies on cpufreq_cpu_get_raw() for its functioning which returns policy only for online CPUs.

The fix is to access the policy data structure for the given CPU directly (which also returns a valid policy for offline CPUs), but the policy itself has to be active (meaning that at least one CPU using it is online) for the frequency table to be returned.

Because we will be using 'cpufreq_cpu_data' now, which is internal to cpufreq-core, lets also move cpufreq_frequency_get_table() to cpufreq.c file.

Reported-and-tested-by: Pi-Cheng Chen pi-cheng.chen@linaro.org Signed-off-by: Viresh Kumar viresh.kumar@linaro.org --- V3-> Changelog improvement suggested by Rafael.

drivers/cpufreq/cpufreq.c | 9 +++++++++ drivers/cpufreq/freq_table.c | 9 --------- 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 36e97a5a7e20..a7b6ac6e048e 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -169,6 +169,15 @@ struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy) } EXPORT_SYMBOL_GPL(get_governor_parent_kobj);

+struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned int cpu) +{ + struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu); + + return policy && !policy_is_inactive(policy) ? + policy->freq_table : NULL; +} +EXPORT_SYMBOL_GPL(cpufreq_frequency_get_table); + static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall) { u64 idle_time; diff --git a/drivers/cpufreq/freq_table.c b/drivers/cpufreq/freq_table.c index df14766a8e06..dfbbf981ed56 100644 --- a/drivers/cpufreq/freq_table.c +++ b/drivers/cpufreq/freq_table.c @@ -297,15 +297,6 @@ int cpufreq_table_validate_and_show(struct cpufreq_policy *policy, } EXPORT_SYMBOL_GPL(cpufreq_table_validate_and_show);

-struct cpufreq_policy *cpufreq_cpu_get_raw(unsigned int cpu); - -struct cpufreq_frequency_table *cpufreq_frequency_get_table(unsigned int cpu) -{ - struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu); - return policy ? policy->freq_table : NULL; -} -EXPORT_SYMBOL_GPL(cpufreq_frequency_get_table); - MODULE_AUTHOR("Dominik Brodowski linux@brodo.de"); MODULE_DESCRIPTION("CPUfreq frequency table helpers"); MODULE_LICENSE("GPL");