Re: [PATCH v3] cpuidle/coupled: Add sanity check for safe_state_index

2015-09-03 Thread Xunlei Pang 
Hi Rafael,

On 3 September 2015 at 09:35, Rafael J. Wysocki  wrote:
> On Monday, August 31, 2015 11:34:05 AM Xunlei Pang wrote:
>> From: Xunlei Pang 
>>
>> Since we are using cpuidle_driver::safe_state_index directly as the
>> target state index, it is better to add the sanity check at the point
>> of registering the driver.
>>
>> Signed-off-by: Xunlei Pang 
>
> I'm queuing this one up for the next PM pull request, thanks!

Thanks!

Regards,
Xunlei

>
>
>> ---
>> v2->v3:
>> Move the code to a new cpuidle_coupled_state_verify() depending on
>> CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED, to avoid using #ifdef in function
>> bodies. Thanks Rafael's comments on this.
>>
>>  drivers/cpuidle/coupled.c | 22 ++
>>  drivers/cpuidle/cpuidle.h |  6 ++
>>  drivers/cpuidle/driver.c  |  4 
>>  3 files changed, 32 insertions(+)
>>
>> diff --git a/drivers/cpuidle/coupled.c b/drivers/cpuidle/coupled.c
>> index 1523e2d..344058f 100644
>> --- a/drivers/cpuidle/coupled.c
>> +++ b/drivers/cpuidle/coupled.c
>> @@ -187,6 +187,28 @@ bool cpuidle_state_is_coupled(struct cpuidle_driver 
>> *drv, int state)
>>  }
>>
>>  /**
>> + * cpuidle_coupled_state_verify - check if the coupled states are correctly 
>> set.
>> + * @drv: struct cpuidle_driver for the platform
>> + *
>> + * Returns 0 for valid state values, a negative error code otherwise:
>> + *  * -EINVAL if any coupled state(safe_state_index) is wrongly set.
>> + */
>> +int cpuidle_coupled_state_verify(struct cpuidle_driver *drv)
>> +{
>> + int i;
>> +
>> + for (i = drv->state_count - 1; i >= 0; i--) {
>> + if (cpuidle_state_is_coupled(drv, i) &&
>> + (drv->safe_state_index == i ||
>> +  drv->safe_state_index < 0 ||
>> +  drv->safe_state_index >= drv->state_count))
>> + return -EINVAL;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +/**
>>   * cpuidle_coupled_set_ready - mark a cpu as ready
>>   * @coupled: the struct coupled that contains the current cpu
>>   */
>> diff --git a/drivers/cpuidle/cpuidle.h b/drivers/cpuidle/cpuidle.h
>> index 178c5ad..f87f399 100644
>> --- a/drivers/cpuidle/cpuidle.h
>> +++ b/drivers/cpuidle/cpuidle.h
>> @@ -35,6 +35,7 @@ extern void cpuidle_remove_sysfs(struct cpuidle_device 
>> *dev);
>>
>>  #ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
>>  bool cpuidle_state_is_coupled(struct cpuidle_driver *drv, int state);
>> +int cpuidle_coupled_state_verify(struct cpuidle_driver *drv);
>>  int cpuidle_enter_state_coupled(struct cpuidle_device *dev,
>>   struct cpuidle_driver *drv, int next_state);
>>  int cpuidle_coupled_register_device(struct cpuidle_device *dev);
>> @@ -46,6 +47,11 @@ bool cpuidle_state_is_coupled(struct cpuidle_driver *drv, 
>> int state)
>>   return false;
>>  }
>>
>> +static inline int cpuidle_coupled_state_verify(struct cpuidle_driver *drv)
>> +{
>> + return 0;
>> +}
>> +
>>  static inline int cpuidle_enter_state_coupled(struct cpuidle_device *dev,
>>   struct cpuidle_driver *drv, int next_state)
>>  {
>> diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c
>> index 5db1478..389ade4 100644
>> --- a/drivers/cpuidle/driver.c
>> +++ b/drivers/cpuidle/driver.c
>> @@ -227,6 +227,10 @@ static int __cpuidle_register_driver(struct 
>> cpuidle_driver *drv)
>>   if (!drv || !drv->state_count)
>>   return -EINVAL;
>>
>> + ret = cpuidle_coupled_state_verify(drv);
>> + if (ret)
>> + return ret;
>> +
>>   if (cpuidle_disabled())
>>   return -ENODEV;
>>
>>
>
> --
> I speak only for myself.
> Rafael J. Wysocki, Intel Open Source Technology Center.
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Re: [PATCH v3] cpuidle/coupled: Add sanity check for safe_state_index

2015-09-03 Thread Xunlei Pang 
Hi Rafael,

On 3 September 2015 at 09:35, Rafael J. Wysocki  wrote:
> On Monday, August 31, 2015 11:34:05 AM Xunlei Pang wrote:
>> From: Xunlei Pang 
>>
>> Since we are using cpuidle_driver::safe_state_index directly as the
>> target state index, it is better to add the sanity check at the point
>> of registering the driver.
>>
>> Signed-off-by: Xunlei Pang 
>
> I'm queuing this one up for the next PM pull request, thanks!

Thanks!

Regards,
Xunlei

>
>
>> ---
>> v2->v3:
>> Move the code to a new cpuidle_coupled_state_verify() depending on
>> CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED, to avoid using #ifdef in function
>> bodies. Thanks Rafael's comments on this.
>>
>>  drivers/cpuidle/coupled.c | 22 ++
>>  drivers/cpuidle/cpuidle.h |  6 ++
>>  drivers/cpuidle/driver.c  |  4 
>>  3 files changed, 32 insertions(+)
>>
>> diff --git a/drivers/cpuidle/coupled.c b/drivers/cpuidle/coupled.c
>> index 1523e2d..344058f 100644
>> --- a/drivers/cpuidle/coupled.c
>> +++ b/drivers/cpuidle/coupled.c
>> @@ -187,6 +187,28 @@ bool cpuidle_state_is_coupled(struct cpuidle_driver 
>> *drv, int state)
>>  }
>>
>>  /**
>> + * cpuidle_coupled_state_verify - check if the coupled states are correctly 
>> set.
>> + * @drv: struct cpuidle_driver for the platform
>> + *
>> + * Returns 0 for valid state values, a negative error code otherwise:
>> + *  * -EINVAL if any coupled state(safe_state_index) is wrongly set.
>> + */
>> +int cpuidle_coupled_state_verify(struct cpuidle_driver *drv)
>> +{
>> + int i;
>> +
>> + for (i = drv->state_count - 1; i >= 0; i--) {
>> + if (cpuidle_state_is_coupled(drv, i) &&
>> + (drv->safe_state_index == i ||
>> +  drv->safe_state_index < 0 ||
>> +  drv->safe_state_index >= drv->state_count))
>> + return -EINVAL;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +/**
>>   * cpuidle_coupled_set_ready - mark a cpu as ready
>>   * @coupled: the struct coupled that contains the current cpu
>>   */
>> diff --git a/drivers/cpuidle/cpuidle.h b/drivers/cpuidle/cpuidle.h
>> index 178c5ad..f87f399 100644
>> --- a/drivers/cpuidle/cpuidle.h
>> +++ b/drivers/cpuidle/cpuidle.h
>> @@ -35,6 +35,7 @@ extern void cpuidle_remove_sysfs(struct cpuidle_device 
>> *dev);
>>
>>  #ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
>>  bool cpuidle_state_is_coupled(struct cpuidle_driver *drv, int state);
>> +int cpuidle_coupled_state_verify(struct cpuidle_driver *drv);
>>  int cpuidle_enter_state_coupled(struct cpuidle_device *dev,
>>   struct cpuidle_driver *drv, int next_state);
>>  int cpuidle_coupled_register_device(struct cpuidle_device *dev);
>> @@ -46,6 +47,11 @@ bool cpuidle_state_is_coupled(struct cpuidle_driver *drv, 
>> int state)
>>   return false;
>>  }
>>
>> +static inline int cpuidle_coupled_state_verify(struct cpuidle_driver *drv)
>> +{
>> + return 0;
>> +}
>> +
>>  static inline int cpuidle_enter_state_coupled(struct cpuidle_device *dev,
>>   struct cpuidle_driver *drv, int next_state)
>>  {
>> diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c
>> index 5db1478..389ade4 100644
>> --- a/drivers/cpuidle/driver.c
>> +++ b/drivers/cpuidle/driver.c
>> @@ -227,6 +227,10 @@ static int __cpuidle_register_driver(struct 
>> cpuidle_driver *drv)
>>   if (!drv || !drv->state_count)
>>   return -EINVAL;
>>
>> + ret = cpuidle_coupled_state_verify(drv);
>> + if (ret)
>> + return ret;
>> +
>>   if (cpuidle_disabled())
>>   return -ENODEV;
>>
>>
>
> --
> I speak only for myself.
> Rafael J. Wysocki, Intel Open Source Technology Center.
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Re: [PATCH v3] cpuidle/coupled: Add sanity check for safe_state_index

2015-09-02 Thread Rafael J. Wysocki 
On Monday, August 31, 2015 11:34:05 AM Xunlei Pang wrote:
> From: Xunlei Pang 
> 
> Since we are using cpuidle_driver::safe_state_index directly as the
> target state index, it is better to add the sanity check at the point
> of registering the driver.
> 
> Signed-off-by: Xunlei Pang 

I'm queuing this one up for the next PM pull request, thanks!


> ---
> v2->v3:
> Move the code to a new cpuidle_coupled_state_verify() depending on 
> CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED, to avoid using #ifdef in function 
> bodies. Thanks Rafael's comments on this.
> 
>  drivers/cpuidle/coupled.c | 22 ++
>  drivers/cpuidle/cpuidle.h |  6 ++
>  drivers/cpuidle/driver.c  |  4 
>  3 files changed, 32 insertions(+)
> 
> diff --git a/drivers/cpuidle/coupled.c b/drivers/cpuidle/coupled.c
> index 1523e2d..344058f 100644
> --- a/drivers/cpuidle/coupled.c
> +++ b/drivers/cpuidle/coupled.c
> @@ -187,6 +187,28 @@ bool cpuidle_state_is_coupled(struct cpuidle_driver 
> *drv, int state)
>  }
>  
>  /**
> + * cpuidle_coupled_state_verify - check if the coupled states are correctly 
> set.
> + * @drv: struct cpuidle_driver for the platform
> + *
> + * Returns 0 for valid state values, a negative error code otherwise:
> + *  * -EINVAL if any coupled state(safe_state_index) is wrongly set.
> + */
> +int cpuidle_coupled_state_verify(struct cpuidle_driver *drv)
> +{
> + int i;
> +
> + for (i = drv->state_count - 1; i >= 0; i--) {
> + if (cpuidle_state_is_coupled(drv, i) &&
> + (drv->safe_state_index == i ||
> +  drv->safe_state_index < 0 ||
> +  drv->safe_state_index >= drv->state_count))
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> +/**
>   * cpuidle_coupled_set_ready - mark a cpu as ready
>   * @coupled: the struct coupled that contains the current cpu
>   */
> diff --git a/drivers/cpuidle/cpuidle.h b/drivers/cpuidle/cpuidle.h
> index 178c5ad..f87f399 100644
> --- a/drivers/cpuidle/cpuidle.h
> +++ b/drivers/cpuidle/cpuidle.h
> @@ -35,6 +35,7 @@ extern void cpuidle_remove_sysfs(struct cpuidle_device 
> *dev);
>  
>  #ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
>  bool cpuidle_state_is_coupled(struct cpuidle_driver *drv, int state);
> +int cpuidle_coupled_state_verify(struct cpuidle_driver *drv);
>  int cpuidle_enter_state_coupled(struct cpuidle_device *dev,
>   struct cpuidle_driver *drv, int next_state);
>  int cpuidle_coupled_register_device(struct cpuidle_device *dev);
> @@ -46,6 +47,11 @@ bool cpuidle_state_is_coupled(struct cpuidle_driver *drv, 
> int state)
>   return false;
>  }
>  
> +static inline int cpuidle_coupled_state_verify(struct cpuidle_driver *drv)
> +{
> + return 0;
> +}
> +
>  static inline int cpuidle_enter_state_coupled(struct cpuidle_device *dev,
>   struct cpuidle_driver *drv, int next_state)
>  {
> diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c
> index 5db1478..389ade4 100644
> --- a/drivers/cpuidle/driver.c
> +++ b/drivers/cpuidle/driver.c
> @@ -227,6 +227,10 @@ static int __cpuidle_register_driver(struct 
> cpuidle_driver *drv)
>   if (!drv || !drv->state_count)
>   return -EINVAL;
>  
> + ret = cpuidle_coupled_state_verify(drv);
> + if (ret)
> + return ret;
> +
>   if (cpuidle_disabled())
>   return -ENODEV;
>  
> 

-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
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Re: [PATCH v3] cpuidle/coupled: Add sanity check for safe_state_index

2015-09-02 Thread Rafael J. Wysocki 
On Monday, August 31, 2015 11:34:05 AM Xunlei Pang wrote:
> From: Xunlei Pang 
> 
> Since we are using cpuidle_driver::safe_state_index directly as the
> target state index, it is better to add the sanity check at the point
> of registering the driver.
> 
> Signed-off-by: Xunlei Pang 

I'm queuing this one up for the next PM pull request, thanks!


> ---
> v2->v3:
> Move the code to a new cpuidle_coupled_state_verify() depending on 
> CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED, to avoid using #ifdef in function 
> bodies. Thanks Rafael's comments on this.
> 
>  drivers/cpuidle/coupled.c | 22 ++
>  drivers/cpuidle/cpuidle.h |  6 ++
>  drivers/cpuidle/driver.c  |  4 
>  3 files changed, 32 insertions(+)
> 
> diff --git a/drivers/cpuidle/coupled.c b/drivers/cpuidle/coupled.c
> index 1523e2d..344058f 100644
> --- a/drivers/cpuidle/coupled.c
> +++ b/drivers/cpuidle/coupled.c
> @@ -187,6 +187,28 @@ bool cpuidle_state_is_coupled(struct cpuidle_driver 
> *drv, int state)
>  }
>  
>  /**
> + * cpuidle_coupled_state_verify - check if the coupled states are correctly 
> set.
> + * @drv: struct cpuidle_driver for the platform
> + *
> + * Returns 0 for valid state values, a negative error code otherwise:
> + *  * -EINVAL if any coupled state(safe_state_index) is wrongly set.
> + */
> +int cpuidle_coupled_state_verify(struct cpuidle_driver *drv)
> +{
> + int i;
> +
> + for (i = drv->state_count - 1; i >= 0; i--) {
> + if (cpuidle_state_is_coupled(drv, i) &&
> + (drv->safe_state_index == i ||
> +  drv->safe_state_index < 0 ||
> +  drv->safe_state_index >= drv->state_count))
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> +/**
>   * cpuidle_coupled_set_ready - mark a cpu as ready
>   * @coupled: the struct coupled that contains the current cpu
>   */
> diff --git a/drivers/cpuidle/cpuidle.h b/drivers/cpuidle/cpuidle.h
> index 178c5ad..f87f399 100644
> --- a/drivers/cpuidle/cpuidle.h
> +++ b/drivers/cpuidle/cpuidle.h
> @@ -35,6 +35,7 @@ extern void cpuidle_remove_sysfs(struct cpuidle_device 
> *dev);
>  
>  #ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
>  bool cpuidle_state_is_coupled(struct cpuidle_driver *drv, int state);
> +int cpuidle_coupled_state_verify(struct cpuidle_driver *drv);
>  int cpuidle_enter_state_coupled(struct cpuidle_device *dev,
>   struct cpuidle_driver *drv, int next_state);
>  int cpuidle_coupled_register_device(struct cpuidle_device *dev);
> @@ -46,6 +47,11 @@ bool cpuidle_state_is_coupled(struct cpuidle_driver *drv, 
> int state)
>   return false;
>  }
>  
> +static inline int cpuidle_coupled_state_verify(struct cpuidle_driver *drv)
> +{
> + return 0;
> +}
> +
>  static inline int cpuidle_enter_state_coupled(struct cpuidle_device *dev,
>   struct cpuidle_driver *drv, int next_state)
>  {
> diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c
> index 5db1478..389ade4 100644
> --- a/drivers/cpuidle/driver.c
> +++ b/drivers/cpuidle/driver.c
> @@ -227,6 +227,10 @@ static int __cpuidle_register_driver(struct 
> cpuidle_driver *drv)
>   if (!drv || !drv->state_count)
>   return -EINVAL;
>  
> + ret = cpuidle_coupled_state_verify(drv);
> + if (ret)
> + return ret;
> +
>   if (cpuidle_disabled())
>   return -ENODEV;
>  
> 

-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
--
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[PATCH v3] cpuidle/coupled: Add sanity check for safe_state_index

2015-08-30 Thread Xunlei Pang 
From: Xunlei Pang 

Since we are using cpuidle_driver::safe_state_index directly as the
target state index, it is better to add the sanity check at the point
of registering the driver.

Signed-off-by: Xunlei Pang 
---
v2->v3:
Move the code to a new cpuidle_coupled_state_verify() depending on 
CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED, to avoid using #ifdef in function 
bodies. Thanks Rafael's comments on this.

 drivers/cpuidle/coupled.c | 22 ++
 drivers/cpuidle/cpuidle.h |  6 ++
 drivers/cpuidle/driver.c  |  4 
 3 files changed, 32 insertions(+)

diff --git a/drivers/cpuidle/coupled.c b/drivers/cpuidle/coupled.c
index 1523e2d..344058f 100644
--- a/drivers/cpuidle/coupled.c
+++ b/drivers/cpuidle/coupled.c
@@ -187,6 +187,28 @@ bool cpuidle_state_is_coupled(struct cpuidle_driver *drv, 
int state)
 }
 
 /**
+ * cpuidle_coupled_state_verify - check if the coupled states are correctly 
set.
+ * @drv: struct cpuidle_driver for the platform
+ *
+ * Returns 0 for valid state values, a negative error code otherwise:
+ *  * -EINVAL if any coupled state(safe_state_index) is wrongly set.
+ */
+int cpuidle_coupled_state_verify(struct cpuidle_driver *drv)
+{
+   int i;
+
+   for (i = drv->state_count - 1; i >= 0; i--) {
+   if (cpuidle_state_is_coupled(drv, i) &&
+   (drv->safe_state_index == i ||
+drv->safe_state_index < 0 ||
+drv->safe_state_index >= drv->state_count))
+   return -EINVAL;
+   }
+
+   return 0;
+}
+
+/**
  * cpuidle_coupled_set_ready - mark a cpu as ready
  * @coupled: the struct coupled that contains the current cpu
  */
diff --git a/drivers/cpuidle/cpuidle.h b/drivers/cpuidle/cpuidle.h
index 178c5ad..f87f399 100644
--- a/drivers/cpuidle/cpuidle.h
+++ b/drivers/cpuidle/cpuidle.h
@@ -35,6 +35,7 @@ extern void cpuidle_remove_sysfs(struct cpuidle_device *dev);
 
 #ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
 bool cpuidle_state_is_coupled(struct cpuidle_driver *drv, int state);
+int cpuidle_coupled_state_verify(struct cpuidle_driver *drv);
 int cpuidle_enter_state_coupled(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int next_state);
 int cpuidle_coupled_register_device(struct cpuidle_device *dev);
@@ -46,6 +47,11 @@ bool cpuidle_state_is_coupled(struct cpuidle_driver *drv, 
int state)
return false;
 }
 
+static inline int cpuidle_coupled_state_verify(struct cpuidle_driver *drv)
+{
+   return 0;
+}
+
 static inline int cpuidle_enter_state_coupled(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int next_state)
 {
diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c
index 5db1478..389ade4 100644
--- a/drivers/cpuidle/driver.c
+++ b/drivers/cpuidle/driver.c
@@ -227,6 +227,10 @@ static int __cpuidle_register_driver(struct cpuidle_driver 
*drv)
if (!drv || !drv->state_count)
return -EINVAL;
 
+   ret = cpuidle_coupled_state_verify(drv);
+   if (ret)
+   return ret;
+
if (cpuidle_disabled())
return -ENODEV;
 
-- 
1.9.1


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[PATCH v3] cpuidle/coupled: Add sanity check for safe_state_index

2015-08-30 Thread Xunlei Pang 
From: Xunlei Pang pang.xun...@linaro.org

Since we are using cpuidle_driver::safe_state_index directly as the
target state index, it is better to add the sanity check at the point
of registering the driver.

Signed-off-by: Xunlei Pang pang.xun...@linaro.org
---
v2-v3:
Move the code to a new cpuidle_coupled_state_verify() depending on 
CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED, to avoid using #ifdef in function 
bodies. Thanks Rafael's comments on this.

 drivers/cpuidle/coupled.c | 22 ++
 drivers/cpuidle/cpuidle.h |  6 ++
 drivers/cpuidle/driver.c  |  4 
 3 files changed, 32 insertions(+)

diff --git a/drivers/cpuidle/coupled.c b/drivers/cpuidle/coupled.c
index 1523e2d..344058f 100644
--- a/drivers/cpuidle/coupled.c
+++ b/drivers/cpuidle/coupled.c
@@ -187,6 +187,28 @@ bool cpuidle_state_is_coupled(struct cpuidle_driver *drv, 
int state)
 }
 
 /**
+ * cpuidle_coupled_state_verify - check if the coupled states are correctly 
set.
+ * @drv: struct cpuidle_driver for the platform
+ *
+ * Returns 0 for valid state values, a negative error code otherwise:
+ *  * -EINVAL if any coupled state(safe_state_index) is wrongly set.
+ */
+int cpuidle_coupled_state_verify(struct cpuidle_driver *drv)
+{
+   int i;
+
+   for (i = drv-state_count - 1; i = 0; i--) {
+   if (cpuidle_state_is_coupled(drv, i) 
+   (drv-safe_state_index == i ||
+drv-safe_state_index  0 ||
+drv-safe_state_index = drv-state_count))
+   return -EINVAL;
+   }
+
+   return 0;
+}
+
+/**
  * cpuidle_coupled_set_ready - mark a cpu as ready
  * @coupled: the struct coupled that contains the current cpu
  */
diff --git a/drivers/cpuidle/cpuidle.h b/drivers/cpuidle/cpuidle.h
index 178c5ad..f87f399 100644
--- a/drivers/cpuidle/cpuidle.h
+++ b/drivers/cpuidle/cpuidle.h
@@ -35,6 +35,7 @@ extern void cpuidle_remove_sysfs(struct cpuidle_device *dev);
 
 #ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
 bool cpuidle_state_is_coupled(struct cpuidle_driver *drv, int state);
+int cpuidle_coupled_state_verify(struct cpuidle_driver *drv);
 int cpuidle_enter_state_coupled(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int next_state);
 int cpuidle_coupled_register_device(struct cpuidle_device *dev);
@@ -46,6 +47,11 @@ bool cpuidle_state_is_coupled(struct cpuidle_driver *drv, 
int state)
return false;
 }
 
+static inline int cpuidle_coupled_state_verify(struct cpuidle_driver *drv)
+{
+   return 0;
+}
+
 static inline int cpuidle_enter_state_coupled(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int next_state)
 {
diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c
index 5db1478..389ade4 100644
--- a/drivers/cpuidle/driver.c
+++ b/drivers/cpuidle/driver.c
@@ -227,6 +227,10 @@ static int __cpuidle_register_driver(struct cpuidle_driver 
*drv)
if (!drv || !drv-state_count)
return -EINVAL;
 
+   ret = cpuidle_coupled_state_verify(drv);
+   if (ret)
+   return ret;
+
if (cpuidle_disabled())
return -ENODEV;
 
-- 
1.9.1


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