Drivers can store their internal per-policy information in
policy->driver_data, lets use it.
we have benefits after this replacing.
1) memory saving.
2) policy is shared by several cpus, per_cpu seems not correct. using
*driver_data* is more reasonable.
3) fix a memory leak in acpi_cpufreq_cpu_exit. as policy->cpu might
change during cpu hotplug. So sometimes we cant't free *data*, use
*driver_data* to fix it.
4) fix a zero return value of get_cur_freq_on_cpu. Only per_cpu of
policy->cpu is set to *data*, if we try to get cpufreq on other cpus, we
get zero instead of correct values. Use *driver_data* to fix it.
Signed-off-by: Pan Xinhui <[email protected]>
---
Changes from V1:
codes style fix, comments update
move cpufreq_cpu_put(policy) after we get *driver_data*
---
drivers/cpufreq/acpi-cpufreq.c | 40 ++++++++++++++++++++++------------------
1 file changed, 22 insertions(+), 18 deletions(-)
diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
index 0136dfc..e7fcaa6 100644
--- a/drivers/cpufreq/acpi-cpufreq.c
+++ b/drivers/cpufreq/acpi-cpufreq.c
@@ -72,8 +72,6 @@ struct acpi_cpufreq_data {
cpumask_var_t freqdomain_cpus;
};
-static DEFINE_PER_CPU(struct acpi_cpufreq_data *, acfreq_data);
-
/* acpi_perf_data is a pointer to percpu data. */
static struct acpi_processor_performance __percpu *acpi_perf_data;
@@ -144,7 +142,7 @@ static int _store_boost(int val)
static ssize_t show_freqdomain_cpus(struct cpufreq_policy *policy, char *buf)
{
- struct acpi_cpufreq_data *data = per_cpu(acfreq_data, policy->cpu);
+ struct acpi_cpufreq_data *data = policy->driver_data;
return cpufreq_show_cpus(data->freqdomain_cpus, buf);
}
@@ -327,7 +325,8 @@ static void drv_write(struct drv_cmd *cmd)
put_cpu();
}
-static u32 get_cur_val(const struct cpumask *mask)
+static u32
+get_cur_val(const struct cpumask *mask, struct acpi_cpufreq_data *data)
{
struct acpi_processor_performance *perf;
struct drv_cmd cmd;
@@ -335,7 +334,7 @@ static u32 get_cur_val(const struct cpumask *mask)
if (unlikely(cpumask_empty(mask)))
return 0;
- switch (per_cpu(acfreq_data, cpumask_first(mask))->cpu_feature) {
+ switch (data->cpu_feature) {
case SYSTEM_INTEL_MSR_CAPABLE:
cmd.type = SYSTEM_INTEL_MSR_CAPABLE;
cmd.addr.msr.reg = MSR_IA32_PERF_CTL;
@@ -346,7 +345,7 @@ static u32 get_cur_val(const struct cpumask *mask)
break;
case SYSTEM_IO_CAPABLE:
cmd.type = SYSTEM_IO_CAPABLE;
- perf = per_cpu(acfreq_data, cpumask_first(mask))->acpi_data;
+ perf = data->acpi_data;
cmd.addr.io.port = perf->control_register.address;
cmd.addr.io.bit_width = perf->control_register.bit_width;
break;
@@ -364,19 +363,24 @@ static u32 get_cur_val(const struct cpumask *mask)
static unsigned int get_cur_freq_on_cpu(unsigned int cpu)
{
- struct acpi_cpufreq_data *data = per_cpu(acfreq_data, cpu);
+ struct acpi_cpufreq_data *data;
+ struct cpufreq_policy *policy;
unsigned int freq;
unsigned int cached_freq;
pr_debug("get_cur_freq_on_cpu (%d)\n", cpu);
- if (unlikely(data == NULL ||
- data->acpi_data == NULL || data->freq_table == NULL)) {
+ policy = cpufreq_cpu_get(cpu);
+ if (unlikely(!policy))
+ return 0;
+
+ data = policy->driver_data;
+ cpufreq_cpu_put(policy);
+ if (unlikely(!data || !data->acpi_data || !data->freq_table))
return 0;
- }
cached_freq = data->freq_table[data->acpi_data->state].frequency;
- freq = extract_freq(get_cur_val(cpumask_of(cpu)), data);
+ freq = extract_freq(get_cur_val(cpumask_of(cpu), data), data);
if (freq != cached_freq) {
/*
* The dreaded BIOS frequency change behind our back.
@@ -397,7 +401,7 @@ static unsigned int check_freqs(const struct cpumask *mask, unsigned int freq,
unsigned int i;
for (i = 0; i < 100; i++) {
- cur_freq = extract_freq(get_cur_val(mask), data);
+ cur_freq = extract_freq(get_cur_val(mask, data), data);
if (cur_freq == freq)
return 1;
udelay(10);
@@ -408,7 +412,7 @@ static unsigned int check_freqs(const struct cpumask *mask, unsigned int freq,
static int acpi_cpufreq_target(struct cpufreq_policy *policy,
unsigned int index)
{
- struct acpi_cpufreq_data *data = per_cpu(acfreq_data, policy->cpu);
+ struct acpi_cpufreq_data *data = policy->driver_data;
struct acpi_processor_performance *perf;
struct drv_cmd cmd;
unsigned int next_perf_state = 0; /* Index into perf table */
@@ -673,7 +677,7 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
}
data->acpi_data = per_cpu_ptr(acpi_perf_data, cpu);
- per_cpu(acfreq_data, cpu) = data;
+ policy->driver_data = data;
if (cpu_has(c, X86_FEATURE_CONSTANT_TSC))
acpi_cpufreq_driver.flags |= CPUFREQ_CONST_LOOPS;
@@ -843,19 +847,19 @@ err_free_mask:
free_cpumask_var(data->freqdomain_cpus);
err_free:
kfree(data);
- per_cpu(acfreq_data, cpu) = NULL;
+ policy->driver_data = NULL;
return result;
}
static int acpi_cpufreq_cpu_exit(struct cpufreq_policy *policy)
{
- struct acpi_cpufreq_data *data = per_cpu(acfreq_data, policy->cpu);
+ struct acpi_cpufreq_data *data = policy->driver_data;
pr_debug("acpi_cpufreq_cpu_exit\n");
if (data) {
- per_cpu(acfreq_data, policy->cpu) = NULL;
+ policy->driver_data = NULL;
acpi_processor_unregister_performance(data->acpi_data,
policy->cpu);
free_cpumask_var(data->freqdomain_cpus);
@@ -868,7 +872,7 @@ static int acpi_cpufreq_cpu_exit(struct cpufreq_policy *policy)
static int acpi_cpufreq_resume(struct cpufreq_policy *policy)
{
- struct acpi_cpufreq_data *data = per_cpu(acfreq_data, policy->cpu);
+ struct acpi_cpufreq_data *data = policy->driver_data;
pr_debug("acpi_cpufreq_resume\n");
--
1.9.1
hi, all
thanks for reviewing.
any comments or advices are welcome :)
I am OOO tomorrow, so response may arrive later.
thanks
xinhui
On 2015年07月07日 20:43, Pan Xinhui wrote:
>
> Drivers can store their internal per-policy information in
> policy->driver_data, lets use it.
>
> we have benefits after this replacing.
> 1) memory saving.
> 2) policy is shared by several cpus, per_cpu seems not correct. using
> *driver_data* is more reasonable.
> 3) fix a memory leak in acpi_cpufreq_cpu_exit. as policy->cpu might
> change during cpu hotplug. So sometimes we cant't free *data*, use
> *driver_data* to fix it.
> 4) fix a zero return value of get_cur_freq_on_cpu. Only per_cpu of
> policy->cpu is set to *data*, if we try to get cpufreq on other cpus, we
> get zero instead of correct values. Use *driver_data* to fix it.
>
> Signed-off-by: Pan Xinhui <[email protected]>
> ---
> Changes from V1:
> codes style fix, comments update
> move cpufreq_cpu_put(policy) after we get *driver_data*
> ---
> drivers/cpufreq/acpi-cpufreq.c | 40 ++++++++++++++++++++++------------------
> 1 file changed, 22 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
> index 0136dfc..e7fcaa6 100644
> --- a/drivers/cpufreq/acpi-cpufreq.c
> +++ b/drivers/cpufreq/acpi-cpufreq.c
> @@ -72,8 +72,6 @@ struct acpi_cpufreq_data {
> cpumask_var_t freqdomain_cpus;
> };
>
> -static DEFINE_PER_CPU(struct acpi_cpufreq_data *, acfreq_data);
> -
> /* acpi_perf_data is a pointer to percpu data. */
> static struct acpi_processor_performance __percpu *acpi_perf_data;
>
> @@ -144,7 +142,7 @@ static int _store_boost(int val)
>
> static ssize_t show_freqdomain_cpus(struct cpufreq_policy *policy, char *buf)
> {
> - struct acpi_cpufreq_data *data = per_cpu(acfreq_data, policy->cpu);
> + struct acpi_cpufreq_data *data = policy->driver_data;
>
> return cpufreq_show_cpus(data->freqdomain_cpus, buf);
> }
> @@ -327,7 +325,8 @@ static void drv_write(struct drv_cmd *cmd)
> put_cpu();
> }
>
> -static u32 get_cur_val(const struct cpumask *mask)
> +static u32
> +get_cur_val(const struct cpumask *mask, struct acpi_cpufreq_data *data)
> {
> struct acpi_processor_performance *perf;
> struct drv_cmd cmd;
> @@ -335,7 +334,7 @@ static u32 get_cur_val(const struct cpumask *mask)
> if (unlikely(cpumask_empty(mask)))
> return 0;
>
> - switch (per_cpu(acfreq_data, cpumask_first(mask))->cpu_feature) {
> + switch (data->cpu_feature) {
> case SYSTEM_INTEL_MSR_CAPABLE:
> cmd.type = SYSTEM_INTEL_MSR_CAPABLE;
> cmd.addr.msr.reg = MSR_IA32_PERF_CTL;
> @@ -346,7 +345,7 @@ static u32 get_cur_val(const struct cpumask *mask)
> break;
> case SYSTEM_IO_CAPABLE:
> cmd.type = SYSTEM_IO_CAPABLE;
> - perf = per_cpu(acfreq_data, cpumask_first(mask))->acpi_data;
> + perf = data->acpi_data;
> cmd.addr.io.port = perf->control_register.address;
> cmd.addr.io.bit_width = perf->control_register.bit_width;
> break;
> @@ -364,19 +363,24 @@ static u32 get_cur_val(const struct cpumask *mask)
>
> static unsigned int get_cur_freq_on_cpu(unsigned int cpu)
> {
> - struct acpi_cpufreq_data *data = per_cpu(acfreq_data, cpu);
> + struct acpi_cpufreq_data *data;
> + struct cpufreq_policy *policy;
> unsigned int freq;
> unsigned int cached_freq;
>
> pr_debug("get_cur_freq_on_cpu (%d)\n", cpu);
>
> - if (unlikely(data == NULL ||
> - data->acpi_data == NULL || data->freq_table == NULL)) {
> + policy = cpufreq_cpu_get(cpu);
> + if (unlikely(!policy))
> + return 0;
> +
> + data = policy->driver_data;
> + cpufreq_cpu_put(policy);
> + if (unlikely(!data || !data->acpi_data || !data->freq_table))
> return 0;
> - }
>
> cached_freq = data->freq_table[data->acpi_data->state].frequency;
> - freq = extract_freq(get_cur_val(cpumask_of(cpu)), data);
> + freq = extract_freq(get_cur_val(cpumask_of(cpu), data), data);
> if (freq != cached_freq) {
> /*
> * The dreaded BIOS frequency change behind our back.
> @@ -397,7 +401,7 @@ static unsigned int check_freqs(const struct cpumask *mask, unsigned int freq,
> unsigned int i;
>
> for (i = 0; i < 100; i++) {
> - cur_freq = extract_freq(get_cur_val(mask), data);
> + cur_freq = extract_freq(get_cur_val(mask, data), data);
> if (cur_freq == freq)
> return 1;
> udelay(10);
> @@ -408,7 +412,7 @@ static unsigned int check_freqs(const struct cpumask *mask, unsigned int freq,
> static int acpi_cpufreq_target(struct cpufreq_policy *policy,
> unsigned int index)
> {
> - struct acpi_cpufreq_data *data = per_cpu(acfreq_data, policy->cpu);
> + struct acpi_cpufreq_data *data = policy->driver_data;
> struct acpi_processor_performance *perf;
> struct drv_cmd cmd;
> unsigned int next_perf_state = 0; /* Index into perf table */
> @@ -673,7 +677,7 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
> }
>
> data->acpi_data = per_cpu_ptr(acpi_perf_data, cpu);
> - per_cpu(acfreq_data, cpu) = data;
> + policy->driver_data = data;
>
> if (cpu_has(c, X86_FEATURE_CONSTANT_TSC))
> acpi_cpufreq_driver.flags |= CPUFREQ_CONST_LOOPS;
> @@ -843,19 +847,19 @@ err_free_mask:
> free_cpumask_var(data->freqdomain_cpus);
> err_free:
> kfree(data);
> - per_cpu(acfreq_data, cpu) = NULL;
> + policy->driver_data = NULL;
>
> return result;
> }
>
> static int acpi_cpufreq_cpu_exit(struct cpufreq_policy *policy)
> {
> - struct acpi_cpufreq_data *data = per_cpu(acfreq_data, policy->cpu);
> + struct acpi_cpufreq_data *data = policy->driver_data;
>
> pr_debug("acpi_cpufreq_cpu_exit\n");
>
> if (data) {
> - per_cpu(acfreq_data, policy->cpu) = NULL;
> + policy->driver_data = NULL;
> acpi_processor_unregister_performance(data->acpi_data,
> policy->cpu);
> free_cpumask_var(data->freqdomain_cpus);
> @@ -868,7 +872,7 @@ static int acpi_cpufreq_cpu_exit(struct cpufreq_policy *policy)
>
> static int acpi_cpufreq_resume(struct cpufreq_policy *policy)
> {
> - struct acpi_cpufreq_data *data = per_cpu(acfreq_data, policy->cpu);
> + struct acpi_cpufreq_data *data = policy->driver_data;
>
> pr_debug("acpi_cpufreq_resume\n");
>
>
On 07-07-15, 20:43, Pan Xinhui wrote:
>
> Drivers can store their internal per-policy information in
> policy->driver_data, lets use it.
>
> we have benefits after this replacing.
> 1) memory saving.
> 2) policy is shared by several cpus, per_cpu seems not correct. using
> *driver_data* is more reasonable.
> 3) fix a memory leak in acpi_cpufreq_cpu_exit. as policy->cpu might
> change during cpu hotplug. So sometimes we cant't free *data*, use
> *driver_data* to fix it.
> 4) fix a zero return value of get_cur_freq_on_cpu. Only per_cpu of
> policy->cpu is set to *data*, if we try to get cpufreq on other cpus, we
> get zero instead of correct values. Use *driver_data* to fix it.
>
> Signed-off-by: Pan Xinhui <[email protected]>
> ---
> Changes from V1:
> codes style fix, comments update
> move cpufreq_cpu_put(policy) after we get *driver_data*
> ---
> drivers/cpufreq/acpi-cpufreq.c | 40 ++++++++++++++++++++++------------------
> 1 file changed, 22 insertions(+), 18 deletions(-)
Acked-by: Viresh Kumar <[email protected]>
--
viresh
Hi Pan,
On Tue, Jul 07, 2015 at 08:43:26PM +0800, Pan Xinhui wrote:
> @@ -364,19 +363,24 @@ static u32 get_cur_val(const struct cpumask *mask)
>
> static unsigned int get_cur_freq_on_cpu(unsigned int cpu)
> {
> - struct acpi_cpufreq_data *data = per_cpu(acfreq_data, cpu);
> + struct acpi_cpufreq_data *data;
> + struct cpufreq_policy *policy;
> unsigned int freq;
> unsigned int cached_freq;
>
> pr_debug("get_cur_freq_on_cpu (%d)\n", cpu);
>
> - if (unlikely(data == NULL ||
> - data->acpi_data == NULL || data->freq_table == NULL)) {
> + policy = cpufreq_cpu_get(cpu);
> + if (unlikely(!policy))
> + return 0;
> +
> + data = policy->driver_data;
> + cpufreq_cpu_put(policy);
If we put policy here can we guarantee that memory pointed to by data
stays valid? Shoudln't we issue cpufreq_cpu_put(policy) after we done
assessing the pointer?
> + if (unlikely(!data || !data->acpi_data || !data->freq_table))
> return 0;
> - }
>
> cached_freq = data->freq_table[data->acpi_data->state].frequency;
> - freq = extract_freq(get_cur_val(cpumask_of(cpu)), data);
> + freq = extract_freq(get_cur_val(cpumask_of(cpu), data), data);
> if (freq != cached_freq) {
> /*
> * The dreaded BIOS frequency change behind our back.
Thanks.
--
Dmitry
Hi Dmitry,
On 07-07-15, 10:11, Dmitry Torokhov wrote:
> > + data = policy->driver_data;
> > + cpufreq_cpu_put(policy);
>
> If we put policy here can we guarantee that memory pointed to by data
> stays valid? Shoudln't we issue cpufreq_cpu_put(policy) after we done
> assessing the pointer?
Ideally yes, you are right. But this was a special case as a callback
of the cpufreq-driver is being called and any such issues must be
handled at the core level, it at all they are relevant.
So probably we can do cpufreq_cpu_put() as soon as we have used it.
--
viresh
hi, Dmitry
thanks for your reply
On 2015年07月08日 01:11, Dmitry Torokhov wrote:
> Hi Pan,
>
> On Tue, Jul 07, 2015 at 08:43:26PM +0800, Pan Xinhui wrote:
>> @@ -364,19 +363,24 @@ static u32 get_cur_val(const struct cpumask *mask)
>>
>> static unsigned int get_cur_freq_on_cpu(unsigned int cpu)
>> {
>> - struct acpi_cpufreq_data *data = per_cpu(acfreq_data, cpu);
>> + struct acpi_cpufreq_data *data;
>> + struct cpufreq_policy *policy;
>> unsigned int freq;
>> unsigned int cached_freq;
>>
>> pr_debug("get_cur_freq_on_cpu (%d)\n", cpu);
>>
>> - if (unlikely(data == NULL ||
>> - data->acpi_data == NULL || data->freq_table == NULL)) {
>> + policy = cpufreq_cpu_get(cpu);
>> + if (unlikely(!policy))
>> + return 0;
>> +
>> + data = policy->driver_data;
>> + cpufreq_cpu_put(policy);
>
> If we put policy here can we guarantee that memory pointed to by data
> stays valid? Shoudln't we issue cpufreq_cpu_put(policy) after we done
> assessing the pointer?
>
*driver_data* is used internal by acpi-cpufreq driver. So probably issuing
cpufreq_cpu_put(policy) after we get *driver_data* is OKay.
The worry you have is about the race. we set *driver_data* to NULL then
free it in ->exit callback while ->get callback is using it.
CPU A CPU B
->get ->exit
data = policy->driver_data;
if (!data ....)
policy->driver_data = NULL;
kfree(data);
access data ....
yes, it might happen in real world. As Viresh says, it is more like to be a core level work.
But this race exists in current codes, too. Maybe down_write policy->rwsem can avoid this race(need double check).
thanks for pointing out it. :)
thanks
xinhui
>> + if (unlikely(!data || !data->acpi_data || !data->freq_table))
>> return 0;
>> - }
>>
>> cached_freq = data->freq_table[data->acpi_data->state].frequency;
>> - freq = extract_freq(get_cur_val(cpumask_of(cpu)), data);
>> + freq = extract_freq(get_cur_val(cpumask_of(cpu), data), data);
>> if (freq != cached_freq) {
>> /*
>> * The dreaded BIOS frequency change behind our back.
>
> Thanks.
>
On Tuesday, July 07, 2015 08:04:43 PM Viresh Kumar wrote:
> On 07-07-15, 20:43, Pan Xinhui wrote:
> >
> > Drivers can store their internal per-policy information in
> > policy->driver_data, lets use it.
> >
> > we have benefits after this replacing.
> > 1) memory saving.
> > 2) policy is shared by several cpus, per_cpu seems not correct. using
> > *driver_data* is more reasonable.
> > 3) fix a memory leak in acpi_cpufreq_cpu_exit. as policy->cpu might
> > change during cpu hotplug. So sometimes we cant't free *data*, use
> > *driver_data* to fix it.
> > 4) fix a zero return value of get_cur_freq_on_cpu. Only per_cpu of
> > policy->cpu is set to *data*, if we try to get cpufreq on other cpus, we
> > get zero instead of correct values. Use *driver_data* to fix it.
> >
> > Signed-off-by: Pan Xinhui <[email protected]>
> > ---
> > Changes from V1:
> > codes style fix, comments update
> > move cpufreq_cpu_put(policy) after we get *driver_data*
> > ---
> > drivers/cpufreq/acpi-cpufreq.c | 40 ++++++++++++++++++++++------------------
> > 1 file changed, 22 insertions(+), 18 deletions(-)
>
> Acked-by: Viresh Kumar <[email protected]>
OK
Does it fix any recent regressions or is it just an old bug?
Rafael
hi, Rafael
thanks for your kind reply. :)
On 2015年07月09日 08:20, Rafael J. Wysocki wrote:
> On Tuesday, July 07, 2015 08:04:43 PM Viresh Kumar wrote:
>> On 07-07-15, 20:43, Pan Xinhui wrote:
>>>
>>> Drivers can store their internal per-policy information in
>>> policy->driver_data, lets use it.
>>>
>>> we have benefits after this replacing.
>>> 1) memory saving.
>>> 2) policy is shared by several cpus, per_cpu seems not correct. using
>>> *driver_data* is more reasonable.
>>> 3) fix a memory leak in acpi_cpufreq_cpu_exit. as policy->cpu might
>>> change during cpu hotplug. So sometimes we cant't free *data*, use
>>> *driver_data* to fix it.
>>> 4) fix a zero return value of get_cur_freq_on_cpu. Only per_cpu of
>>> policy->cpu is set to *data*, if we try to get cpufreq on other cpus, we
>>> get zero instead of correct values. Use *driver_data* to fix it.
>>>
>>> Signed-off-by: Pan Xinhui <[email protected]>
>>> ---
>>> Changes from V1:
>>> codes style fix, comments update
>>> move cpufreq_cpu_put(policy) after we get *driver_data*
>>> ---
>>> drivers/cpufreq/acpi-cpufreq.c | 40 ++++++++++++++++++++++------------------
>>> 1 file changed, 22 insertions(+), 18 deletions(-)
>>
>> Acked-by: Viresh Kumar <[email protected]>
>
> OK
>
> Does it fix any recent regressions or is it just an old bug?
>
This patch achieve old bug fix and codes improvements. In past days, policy has no field *driver_data*, So
acpi-cpufreq driver has to use per_cpu to store some extra information. But it did not take good care of every scenarios.
Now cpufreq core makes awesome effort to store more per-policy information in policy. We can make use of this feature. So I
cook this patch. :)
I am preparing two patches for other two issues in acpi-cpufreq driver based on this patch.
I will fix them step by step. :)
thanks
xinhui
> Rafael
>
On Thursday, July 09, 2015 09:28:30 AM Pan Xinhui wrote:
> hi, Rafael
> thanks for your kind reply. :)
>
> On 2015年07月09日 08:20, Rafael J. Wysocki wrote:
> > On Tuesday, July 07, 2015 08:04:43 PM Viresh Kumar wrote:
> >> On 07-07-15, 20:43, Pan Xinhui wrote:
> >>>
> >>> Drivers can store their internal per-policy information in
> >>> policy->driver_data, lets use it.
> >>>
> >>> we have benefits after this replacing.
> >>> 1) memory saving.
> >>> 2) policy is shared by several cpus, per_cpu seems not correct. using
> >>> *driver_data* is more reasonable.
> >>> 3) fix a memory leak in acpi_cpufreq_cpu_exit. as policy->cpu might
> >>> change during cpu hotplug. So sometimes we cant't free *data*, use
> >>> *driver_data* to fix it.
> >>> 4) fix a zero return value of get_cur_freq_on_cpu. Only per_cpu of
> >>> policy->cpu is set to *data*, if we try to get cpufreq on other cpus, we
> >>> get zero instead of correct values. Use *driver_data* to fix it.
> >>>
> >>> Signed-off-by: Pan Xinhui <[email protected]>
> >>> ---
> >>> Changes from V1:
> >>> codes style fix, comments update
> >>> move cpufreq_cpu_put(policy) after we get *driver_data*
> >>> ---
> >>> drivers/cpufreq/acpi-cpufreq.c | 40 ++++++++++++++++++++++------------------
> >>> 1 file changed, 22 insertions(+), 18 deletions(-)
> >>
> >> Acked-by: Viresh Kumar <[email protected]>
> >
> > OK
> >
> > Does it fix any recent regressions or is it just an old bug?
> >
>
> This patch achieve old bug fix and codes improvements. In past days, policy has no field *driver_data*, So
> acpi-cpufreq driver has to use per_cpu to store some extra information. But it did not take good care of every scenarios.
> Now cpufreq core makes awesome effort to store more per-policy information in policy. We can make use of this feature. So I
> cook this patch. :)
OK, patch applied, thanks!
> I am preparing two patches for other two issues in acpi-cpufreq driver based on this patch.
> I will fix them step by step. :)
Thanks for doing that!
Rafael