Re: [PATCH 1/1] thermal: fix cpu_cooling max_level behavior

From: Eduardo Valentin
Date: Sat Jan 04 2014 - 08:53:49 EST


On 02-01-2014 00:02, Zhang Rui wrote:
> On Fri, 2013-12-06 at 09:52 -0400, Eduardo Valentin wrote:
>> On 13-11-2013 14:11, Eduardo Valentin wrote:
>>> As per Documentation/thermal/sysfs-api.txt, max_level
>>> is an index, not a counter. Thus, in case a CPU has
>>> 3 valid frequencies, max_level is expected to be 2, for instance.
>>>
>>> The current code makes max_level == number of valid frequencies,
>>> which is bogus. This patch fix the cpu_cooling device by
>>> ranging max_level properly.
>>>
> good catch.
>>> Reported-by: Carlos Hernandez <ceh@xxxxxx>
>>> Signed-off-by: Eduardo Valentin <eduardo.valentin@xxxxxx>
>>
>> Rui,
>>
>> Can you please consider pushing this fix?
>>
> applied.
>
>>> ---
>>> drivers/thermal/cpu_cooling.c | 6 ++++--
>>> 1 file changed, 4 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c
>>> index d179028..d0f8f8b5 100644
>>> --- a/drivers/thermal/cpu_cooling.c
>>> +++ b/drivers/thermal/cpu_cooling.c
>>> @@ -173,6 +173,8 @@ static int get_property(unsigned int cpu, unsigned long input,
>>> freq = table[i].frequency;
>>> max_level++;
>>> }
>>> + /* max_level is an index, not a counter */
>>> + max_level--;
>>>
> I think we should check the max_level first, like the patch I attached
> below.
>
> thanks,
> rui
>
>>From a116776f7b6052599df0c67db29c30ea9d69d7ee Mon Sep 17 00:00:00 2001
> From: Zhang Rui <rui.zhang@xxxxxxxxx>
> Date: Thu, 2 Jan 2014 11:57:48 +0800
> Subject: [PATCH] Thermal cpu cooling: return error if no valid cpu frequency
> entry
>
> Signed-off-by: Zhang Rui <rui.zhang@xxxxxxxxx>
> ---
> drivers/thermal/cpu_cooling.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c
> index cc556a8..bb486b4 100644
> --- a/drivers/thermal/cpu_cooling.c
> +++ b/drivers/thermal/cpu_cooling.c
> @@ -173,6 +173,11 @@ static int get_property(unsigned int cpu, unsigned long input,
> freq = table[i].frequency;
> max_level++;
> }
> +
> + /* No valid cpu frequency entry */
> + if (max_level == 0)
> + return -EINVAL;
> +

Agreed. For the patch above:

Acked-by: Eduardo Valentin <eduardo.valentin@xxxxxx>

> /* max_level is an index, not a counter */
> max_level--;
>
>


--
You have got to be excited about what you are doing. (L. Lamport)

Eduardo Valentin

Attachment: signature.asc
Description: OpenPGP digital signature