diff mbox series

[08/11] PM / devfreq: check get_dev_status in devfreq_update_stats

Message ID 1615294733-22761-9-git-send-email-aisheng.dong@nxp.com (mailing list archive)
State New, archived
Delegated to: Chanwoo Choi
Headers show
Series PM / devfreq: a few small fixes and improvements | expand

Commit Message

Dong Aisheng March 9, 2021, 12:58 p.m. UTC
Check .get_dev_status() in devfreq_update_stats in case it's abused
when a device does not provide it.

Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
---
 drivers/devfreq/governor.h | 3 +++
 1 file changed, 3 insertions(+)

Comments

Chanwoo Choi March 9, 2021, 4:02 p.m. UTC | #1
On 21. 3. 9. 오후 9:58, Dong Aisheng wrote:
> Check .get_dev_status() in devfreq_update_stats in case it's abused
> when a device does not provide it.
> 
> Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
> ---
>   drivers/devfreq/governor.h | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/devfreq/governor.h b/drivers/devfreq/governor.h
> index 31af6d072a10..67a6dbdd5d23 100644
> --- a/drivers/devfreq/governor.h
> +++ b/drivers/devfreq/governor.h
> @@ -89,6 +89,9 @@ int devfreq_update_target(struct devfreq *devfreq, unsigned long freq);
>   
>   static inline int devfreq_update_stats(struct devfreq *df)
>   {
> +	if (!df->profile->get_dev_status)
> +		return -EINVAL;
> +
>   	return df->profile->get_dev_status(df->dev.parent, &df->last_status);
>   }
>   #endif /* _GOVERNOR_H */
> 

Applied it. Thanks.
Chanwoo Choi March 9, 2021, 4:20 p.m. UTC | #2
On 21. 3. 9. 오후 9:58, Dong Aisheng wrote:
> Check .get_dev_status() in devfreq_update_stats in case it's abused
> when a device does not provide it.
> 
> Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
> ---
>   drivers/devfreq/governor.h | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/devfreq/governor.h b/drivers/devfreq/governor.h
> index 31af6d072a10..67a6dbdd5d23 100644
> --- a/drivers/devfreq/governor.h
> +++ b/drivers/devfreq/governor.h
> @@ -89,6 +89,9 @@ int devfreq_update_target(struct devfreq *devfreq, unsigned long freq);
>   
>   static inline int devfreq_update_stats(struct devfreq *df)
>   {
> +	if (!df->profile->get_dev_status)
> +		return -EINVAL;
> +

I'm considering the following method instead of returning the error
when .get_dev_status is NULL.

	if (!df->profile->get_dev_status) {
		df->last_status.total_time = 0;
		df->last_status.busy_time = 0;
		df->last_status.current_frequency = 0;
		return 0;	
	}	

>   	return df->profile->get_dev_status(df->dev.parent, &df->last_status);
>   }
>   #endif /* _GOVERNOR_H */
>
Dong Aisheng March 10, 2021, 3 a.m. UTC | #3
On Wed, Mar 10, 2021 at 12:20 AM Chanwoo Choi <cwchoi00@gmail.com> wrote:
>
> On 21. 3. 9. 오후 9:58, Dong Aisheng wrote:
> > Check .get_dev_status() in devfreq_update_stats in case it's abused
> > when a device does not provide it.
> >
> > Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
> > ---
> >   drivers/devfreq/governor.h | 3 +++
> >   1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/devfreq/governor.h b/drivers/devfreq/governor.h
> > index 31af6d072a10..67a6dbdd5d23 100644
> > --- a/drivers/devfreq/governor.h
> > +++ b/drivers/devfreq/governor.h
> > @@ -89,6 +89,9 @@ int devfreq_update_target(struct devfreq *devfreq, unsigned long freq);
> >
> >   static inline int devfreq_update_stats(struct devfreq *df)
> >   {
> > +     if (!df->profile->get_dev_status)
> > +             return -EINVAL;
> > +
>
> I'm considering the following method instead of returning the error
> when .get_dev_status is NULL.
>
>         if (!df->profile->get_dev_status) {
>                 df->last_status.total_time = 0;
>                 df->last_status.busy_time = 0;
>                 df->last_status.current_frequency = 0;
>                 return 0;
>         }

I might  suggest not cause it's meaningless for ondemand governor but
introducing confusing. Simply return error could make the life a bit easier.
does it make sense to you?

Regards
Aisheng

>
> >       return df->profile->get_dev_status(df->dev.parent, &df->last_status);
> >   }
> >   #endif /* _GOVERNOR_H */
> >
>
>
> --
> Best Regards,
> Samsung Electronics
> Chanwoo Choi
Chanwoo Choi March 11, 2021, 7:01 a.m. UTC | #4
On 3/10/21 12:00 PM, Dong Aisheng wrote:
> On Wed, Mar 10, 2021 at 12:20 AM Chanwoo Choi <cwchoi00@gmail.com> wrote:
>>
>> On 21. 3. 9. 오후 9:58, Dong Aisheng wrote:
>>> Check .get_dev_status() in devfreq_update_stats in case it's abused
>>> when a device does not provide it.
>>>
>>> Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
>>> ---
>>>   drivers/devfreq/governor.h | 3 +++
>>>   1 file changed, 3 insertions(+)
>>>
>>> diff --git a/drivers/devfreq/governor.h b/drivers/devfreq/governor.h
>>> index 31af6d072a10..67a6dbdd5d23 100644
>>> --- a/drivers/devfreq/governor.h
>>> +++ b/drivers/devfreq/governor.h
>>> @@ -89,6 +89,9 @@ int devfreq_update_target(struct devfreq *devfreq, unsigned long freq);
>>>
>>>   static inline int devfreq_update_stats(struct devfreq *df)
>>>   {
>>> +     if (!df->profile->get_dev_status)
>>> +             return -EINVAL;
>>> +
>>
>> I'm considering the following method instead of returning the error
>> when .get_dev_status is NULL.
>>
>>         if (!df->profile->get_dev_status) {
>>                 df->last_status.total_time = 0;
>>                 df->last_status.busy_time = 0;
>>                 df->last_status.current_frequency = 0;
>>                 return 0;
>>         }
> 
> I might  suggest not cause it's meaningless for ondemand governor but
> introducing confusing. Simply return error could make the life a bit easier.
> does it make sense to you?

Actually, I considered the some corner case as following:
We can see the simple_ondemand governor through available_governors
even if the devfreq driver doesn't implement the .get_dev_status.
In this corner case, My intention tried to prevent the error
on this case. But, actually, it is different issue. I'll fix
this issue when get_dev_status is NULL, don't show the
simple_ondemand governor name through available_governors
on other patch.

And I applied it. Thanks.

> 
> Regards
> Aisheng
> 
>>
>>>       return df->profile->get_dev_status(df->dev.parent, &df->last_status);
>>>   }
>>>   #endif /* _GOVERNOR_H */
>>>
>>
>>
>> --
>> Best Regards,
>> Samsung Electronics
>> Chanwoo Choi
> 
>
diff mbox series

Patch

diff --git a/drivers/devfreq/governor.h b/drivers/devfreq/governor.h
index 31af6d072a10..67a6dbdd5d23 100644
--- a/drivers/devfreq/governor.h
+++ b/drivers/devfreq/governor.h
@@ -89,6 +89,9 @@  int devfreq_update_target(struct devfreq *devfreq, unsigned long freq);
 
 static inline int devfreq_update_stats(struct devfreq *df)
 {
+	if (!df->profile->get_dev_status)
+		return -EINVAL;
+
 	return df->profile->get_dev_status(df->dev.parent, &df->last_status);
 }
 #endif /* _GOVERNOR_H */