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
State Accepted
Commit b19e13463a1054b1b51f4314a1a53da02aed776f
Headers show
Series None | expand

Commit Message

Aisheng Dong 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 11, 2021, 7:01 a.m. UTC | #1
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

> 

> 



-- 
Best Regards,
Chanwoo Choi
Samsung Electronics
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 */