diff mbox

[1/1] ARM: ux500:mach-ux500/cpuidle.c spinlock dis-matching

Message ID CAKvkGKdoWxmnRbNvn_SikRhzsyyzqEC99XtSM9ZeaVGjEA_Ydw@mail.gmail.com (mailing list archive)
State New, archived
Headers show

Commit Message

??? Dec. 28, 2012, 7:06 a.m. UTC 
Hi Daniel,

       I think we must unlock the master spinlock even
prcmu_gic_decouple function now always return 0.
       Could you give some infos about this?
Thanks.




Steve Zhan

Comments

??? Jan. 4, 2013, 2:46 a.m. UTC | #1 
Hi all,

Is this not bug?

steve.

2012/12/28, steve.zhan <zhanzhenbo@gmail.com>:
> Hi Daniel,
>
>        I think we must unlock the master spinlock even
> prcmu_gic_decouple function now always return 0.
>        Could you give some infos about this?
> Thanks.
>
> diff --git a/arch/arm/mach-ux500/cpuidle.c b/arch/arm/mach-ux500/cpuidle.c
> index b54884bd..b0759ce 100644
> --- a/arch/arm/mach-ux500/cpuidle.c
> +++ b/arch/arm/mach-ux500/cpuidle.c
> @@ -29,6 +29,7 @@ static inline int ux500_enter_idle(struct cpuidle_device
> *dev,
>  {
>         int this_cpu = smp_processor_id();
>         bool recouple = false;
> +       bool locked = false;
>
>         clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &this_cpu);
>
> @@ -39,6 +40,8 @@ static inline int ux500_enter_idle(struct cpuidle_device
> *dev,
>                 if (!spin_trylock(&master_lock))
>                         goto wfi;
>
> +               locked = true;
> +
>                 /* decouple the gic from the A9 cores */
>                 if (prcmu_gic_decouple())
>                         goto out;
> @@ -76,7 +79,7 @@ static inline int ux500_enter_idle(struct cpuidle_device
> *dev,
>                 /* When we switch to retention, the prcmu is in charge
>                  * of recoupling the gic automatically */
>                 recouple = false;
> -
> +               locked = false;
>                 spin_unlock(&master_lock);
>         }
>  wfi:
> @@ -86,7 +89,8 @@ out:
>
>         if (recouple) {
>                 prcmu_gic_recouple();
> -               spin_unlock(&master_lock);
> +               if (locked)
> +                       spin_unlock(&master_lock);
>         }
>
>         clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &this_cpu);
>
>
>
> Steve Zhan
>
Daniel Lezcano Jan. 6, 2013, 4:23 p.m. UTC | #2 
On 12/28/2012 08:06 AM, steve.zhan wrote:
> Hi Daniel,

Hi Steve,

sorry I missed your email.

> 
>        I think we must unlock the master spinlock even
> prcmu_gic_decouple function now always return 0.
>        Could you give some infos about this?

I agree, that would be cleaner.

AFAICS, your patch does not solve the problem because 'recouple' will be
false if prcmu_gic_decouple fails, so the lock will never be release.

That will be simpler to do:

if (prcmu_gic_decouple()) {
	spin_unlock(&master);
	goto out;
}

no ?

> Thanks.
> 
> diff --git a/arch/arm/mach-ux500/cpuidle.c b/arch/arm/mach-ux500/cpuidle.c
> index b54884bd..b0759ce 100644
> --- a/arch/arm/mach-ux500/cpuidle.c
> +++ b/arch/arm/mach-ux500/cpuidle.c
> @@ -29,6 +29,7 @@ static inline int ux500_enter_idle(struct cpuidle_device *dev,
>  {
>         int this_cpu = smp_processor_id();
>         bool recouple = false;
> +       bool locked = false;
> 
>         clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &this_cpu);
> 
> @@ -39,6 +40,8 @@ static inline int ux500_enter_idle(struct cpuidle_device *dev,
>                 if (!spin_trylock(&master_lock))
>                         goto wfi;
> 
> +               locked = true;
> +
>                 /* decouple the gic from the A9 cores */
>                 if (prcmu_gic_decouple())
>                         goto out;
> @@ -76,7 +79,7 @@ static inline int ux500_enter_idle(struct cpuidle_device *dev,
>                 /* When we switch to retention, the prcmu is in charge
>                  * of recoupling the gic automatically */
>                 recouple = false;
> -
> +               locked = false;
>                 spin_unlock(&master_lock);
>         }
>  wfi:
> @@ -86,7 +89,8 @@ out:
> 
>         if (recouple) {
>                 prcmu_gic_recouple();
> -               spin_unlock(&master_lock);
> +               if (locked)
> +                       spin_unlock(&master_lock);
>         }
> 
>         clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &this_cpu);
> 
> 
> 
> Steve Zhan
>
??? Jan. 7, 2013, 5:50 a.m. UTC | #3 
Hi Daniel,

    Happy new year, Thank you for reply.
Sorry for that i have refer the old patch email.
I have updated the patch, Pls check the URL:
http://lists.infradead.org/pipermail/linux-arm-kernel/2012-December/138939.html
Now i am using gmail GUI tools to send mail, i will switch email tool
to MUTT to commit the other patchs in the future.



--------------
steve.zhan

2013/1/7, Daniel Lezcano <daniel.lezcano@linaro.org>:
> On 12/28/2012 08:06 AM, steve.zhan wrote:
>> Hi Daniel,
>
> Hi Steve,
>
> sorry I missed your email.
>
>>
>>        I think we must unlock the master spinlock even
>> prcmu_gic_decouple function now always return 0.
>>        Could you give some infos about this?
>
> I agree, that would be cleaner.
>
> AFAICS, your patch does not solve the problem because 'recouple' will be
> false if prcmu_gic_decouple fails, so the lock will never be release.
>
> That will be simpler to do:
>
> if (prcmu_gic_decouple()) {
> 	spin_unlock(&master);
> 	goto out;
> }
>
> no ?
>
>> Thanks.
>>
>> diff --git a/arch/arm/mach-ux500/cpuidle.c
>> b/arch/arm/mach-ux500/cpuidle.c
>> index b54884bd..b0759ce 100644
>> --- a/arch/arm/mach-ux500/cpuidle.c
>> +++ b/arch/arm/mach-ux500/cpuidle.c
>> @@ -29,6 +29,7 @@ static inline int ux500_enter_idle(struct cpuidle_device
>> *dev,
>>  {
>>         int this_cpu = smp_processor_id();
>>         bool recouple = false;
>> +       bool locked = false;
>>
>>         clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &this_cpu);
>>
>> @@ -39,6 +40,8 @@ static inline int ux500_enter_idle(struct cpuidle_device
>> *dev,
>>                 if (!spin_trylock(&master_lock))
>>                         goto wfi;
>>
>> +               locked = true;
>> +
>>                 /* decouple the gic from the A9 cores */
>>                 if (prcmu_gic_decouple())
>>                         goto out;
>> @@ -76,7 +79,7 @@ static inline int ux500_enter_idle(struct cpuidle_device
>> *dev,
>>                 /* When we switch to retention, the prcmu is in charge
>>                  * of recoupling the gic automatically */
>>                 recouple = false;
>> -
>> +               locked = false;
>>                 spin_unlock(&master_lock);
>>         }
>>  wfi:
>> @@ -86,7 +89,8 @@ out:
>>
>>         if (recouple) {
>>                 prcmu_gic_recouple();
>> -               spin_unlock(&master_lock);
>> +               if (locked)
>> +                       spin_unlock(&master_lock);
>>         }
>>
>>         clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &this_cpu);
>>
>>
>>
>> Steve Zhan
>>
>
>
> --
>  <http://www.linaro.org/> Linaro.org ? Open source software for ARM SoCs
>
> Follow Linaro:  <http://www.facebook.com/pages/Linaro> Facebook |
> <http://twitter.com/#!/linaroorg> Twitter |
> <http://www.linaro.org/linaro-blog/> Blog
>
>
Daniel Lezcano Jan. 7, 2013, 8:54 a.m. UTC | #4 
On 01/07/2013 06:50 AM, steve.zhan wrote:
> Hi Daniel,
> 
>     Happy new year, Thank you for reply.
> Sorry for that i have refer the old patch email.
> I have updated the patch, Pls check the URL:
> http://lists.infradead.org/pipermail/linux-arm-kernel/2012-December/138939.html
> Now i am using gmail GUI tools to send mail, i will switch email tool
> to MUTT to commit the other patchs in the future.

Ok.

Please do not introduce a new variable which is at the end pointless and
add more complexity.

You can simply remove the if statement for prcmu_gic_decouple(), or
unlock if it fails.

Thanks
  -- Daniel

> --------------
> steve.zhan
> 
> 2013/1/7, Daniel Lezcano <daniel.lezcano@linaro.org>:
>> On 12/28/2012 08:06 AM, steve.zhan wrote:
>>> Hi Daniel,
>>
>> Hi Steve,
>>
>> sorry I missed your email.
>>
>>>
>>>        I think we must unlock the master spinlock even
>>> prcmu_gic_decouple function now always return 0.
>>>        Could you give some infos about this?
>>
>> I agree, that would be cleaner.
>>
>> AFAICS, your patch does not solve the problem because 'recouple' will be
>> false if prcmu_gic_decouple fails, so the lock will never be release.
>>
>> That will be simpler to do:
>>
>> if (prcmu_gic_decouple()) {
>> 	spin_unlock(&master);
>> 	goto out;
>> }
>>
>> no ?
>>
>>> Thanks.
>>>
>>> diff --git a/arch/arm/mach-ux500/cpuidle.c
>>> b/arch/arm/mach-ux500/cpuidle.c
>>> index b54884bd..b0759ce 100644
>>> --- a/arch/arm/mach-ux500/cpuidle.c
>>> +++ b/arch/arm/mach-ux500/cpuidle.c
>>> @@ -29,6 +29,7 @@ static inline int ux500_enter_idle(struct cpuidle_device
>>> *dev,
>>>  {
>>>         int this_cpu = smp_processor_id();
>>>         bool recouple = false;
>>> +       bool locked = false;
>>>
>>>         clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &this_cpu);
>>>
>>> @@ -39,6 +40,8 @@ static inline int ux500_enter_idle(struct cpuidle_device
>>> *dev,
>>>                 if (!spin_trylock(&master_lock))
>>>                         goto wfi;
>>>
>>> +               locked = true;
>>> +
>>>                 /* decouple the gic from the A9 cores */
>>>                 if (prcmu_gic_decouple())
>>>                         goto out;
>>> @@ -76,7 +79,7 @@ static inline int ux500_enter_idle(struct cpuidle_device
>>> *dev,
>>>                 /* When we switch to retention, the prcmu is in charge
>>>                  * of recoupling the gic automatically */
>>>                 recouple = false;
>>> -
>>> +               locked = false;
>>>                 spin_unlock(&master_lock);
>>>         }
>>>  wfi:
>>> @@ -86,7 +89,8 @@ out:
>>>
>>>         if (recouple) {
>>>                 prcmu_gic_recouple();
>>> -               spin_unlock(&master_lock);
>>> +               if (locked)
>>> +                       spin_unlock(&master_lock);
>>>         }
>>>
>>>         clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &this_cpu);
>>>
>>>
>>>
>>> Steve Zhan
>>>
>>
>>
>> --
>>  <http://www.linaro.org/> Linaro.org ? Open source software for ARM SoCs
>>
>> Follow Linaro:  <http://www.facebook.com/pages/Linaro> Facebook |
>> <http://twitter.com/#!/linaroorg> Twitter |
>> <http://www.linaro.org/linaro-blog/> Blog
>>
>>
> 
>
diff mbox

Patch

diff --git a/arch/arm/mach-ux500/cpuidle.c b/arch/arm/mach-ux500/cpuidle.c
index b54884bd..b0759ce 100644
--- a/arch/arm/mach-ux500/cpuidle.c
+++ b/arch/arm/mach-ux500/cpuidle.c
@@ -29,6 +29,7 @@  static inline int ux500_enter_idle(struct cpuidle_device *dev,
 {
        int this_cpu = smp_processor_id();
        bool recouple = false;
+       bool locked = false;

        clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &this_cpu);

@@ -39,6 +40,8 @@  static inline int ux500_enter_idle(struct cpuidle_device *dev,
                if (!spin_trylock(&master_lock))
                        goto wfi;

+               locked = true;
+
                /* decouple the gic from the A9 cores */
                if (prcmu_gic_decouple())
                        goto out;
@@ -76,7 +79,7 @@  static inline int ux500_enter_idle(struct cpuidle_device *dev,
                /* When we switch to retention, the prcmu is in charge
                 * of recoupling the gic automatically */
                recouple = false;
-
+               locked = false;
                spin_unlock(&master_lock);
        }
 wfi:
@@ -86,7 +89,8 @@  out:

        if (recouple) {
                prcmu_gic_recouple();
-               spin_unlock(&master_lock);
+               if (locked)
+                       spin_unlock(&master_lock);
        }

        clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &this_cpu);