On Fri, Dec 15, 2023 at 8:23 AM Christophe Leroy
<[email protected]> wrote:
>
> From: George Stark <[email protected]>
>
> Using of devm API leads to a certain order of releasing resources.
> So all dependent resources which are not devm-wrapped should be deleted
> with respect to devm-release order. Mutex is one of such objects that
> often is bound to other resources and has no own devm wrapping.
> Since mutex_destroy() actually does nothing in non-debug builds
> frequently calling mutex_destroy() is just ignored which is safe for now
> but wrong formally and can lead to a problem if mutex_destroy() will be
> extended so introduce devm_mutex_init()
Missing period.
...
> } while (0)
> #endif /* CONFIG_PREEMPT_RT */
^^^ (1)
> +struct device;
> +
> +/*
> + * devm_mutex_init() registers a function that calls mutex_destroy()
> + * when the ressource is released.
> + *
> + * When mutex_destroy() is a not, there is no need to register that
> + * function.
> + */
> +#ifdef CONFIG_DEBUG_MUTEXES
Shouldn't this be
#if defined(CONFIG_DEBUG_MUTEXES) && !defined(CONFIG_PREEMPT_RT)
(see (1) as well)?
> +void mutex_destroy(struct mutex *lock);
> +int devm_mutex_init(struct device *dev, struct mutex *lock);
> +#else
> +static inline void mutex_destroy(struct mutex *lock) {}
> +
> +static inline int devm_mutex_init(struct device *dev, struct mutex *lock)
> +{
> + mutex_init(lock);
> + return 0;
> +}
> +#endif
--
With Best Regards,
Andy Shevchenko
Le 15/12/2023 à 16:58, Andy Shevchenko a écrit :
> On Fri, Dec 15, 2023 at 8:23 AM Christophe Leroy
> <[email protected]> wrote:
>>
>> From: George Stark <[email protected]>
>>
>> Using of devm API leads to a certain order of releasing resources.
>> So all dependent resources which are not devm-wrapped should be deleted
>> with respect to devm-release order. Mutex is one of such objects that
>> often is bound to other resources and has no own devm wrapping.
>> Since mutex_destroy() actually does nothing in non-debug builds
>> frequently calling mutex_destroy() is just ignored which is safe for now
>> but wrong formally and can lead to a problem if mutex_destroy() will be
>> extended so introduce devm_mutex_init()
>
> Missing period.
>
> ...
>
>> } while (0)
>> #endif /* CONFIG_PREEMPT_RT */
>
> ^^^ (1)
>
>> +struct device;
>> +
>> +/*
>> + * devm_mutex_init() registers a function that calls mutex_destroy()
>> + * when the ressource is released.
>> + *
>> + * When mutex_destroy() is a not, there is no need to register that
>> + * function.
>> + */
>> +#ifdef CONFIG_DEBUG_MUTEXES
>
> Shouldn't this be
>
> #if defined(CONFIG_DEBUG_MUTEXES) && !defined(CONFIG_PREEMPT_RT)
>
> (see (1) as well)?
Isn't needed, handled by Kconfig:
config DEBUG_MUTEXES
bool "Mutex debugging: basic checks"
depends on DEBUG_KERNEL && !PREEMPT_RT
>
>> +void mutex_destroy(struct mutex *lock);
>> +int devm_mutex_init(struct device *dev, struct mutex *lock);
>> +#else
>> +static inline void mutex_destroy(struct mutex *lock) {}
>> +
>> +static inline int devm_mutex_init(struct device *dev, struct mutex *lock)
>> +{
>> + mutex_init(lock);
>> + return 0;
>> +}
>> +#endif
>
On 12/15/23 10:58, Andy Shevchenko wrote:
> On Fri, Dec 15, 2023 at 8:23 AM Christophe Leroy
> <[email protected]> wrote:
>> From: George Stark <[email protected]>
>>
>> Using of devm API leads to a certain order of releasing resources.
>> So all dependent resources which are not devm-wrapped should be deleted
>> with respect to devm-release order. Mutex is one of such objects that
>> often is bound to other resources and has no own devm wrapping.
>> Since mutex_destroy() actually does nothing in non-debug builds
>> frequently calling mutex_destroy() is just ignored which is safe for now
>> but wrong formally and can lead to a problem if mutex_destroy() will be
>> extended so introduce devm_mutex_init()
> Missing period.
>
> ...
>
>> } while (0)
>> #endif /* CONFIG_PREEMPT_RT */
> ^^^ (1)
>
>> +struct device;
>> +
>> +/*
>> + * devm_mutex_init() registers a function that calls mutex_destroy()
>> + * when the ressource is released.
>> + *
>> + * When mutex_destroy() is a not, there is no need to register that
>> + * function.
>> + */
>> +#ifdef CONFIG_DEBUG_MUTEXES
> Shouldn't this be
>
> #if defined(CONFIG_DEBUG_MUTEXES) && !defined(CONFIG_PREEMPT_RT)
>
> (see (1) as well)?
CONFIG_DEBUG_MUTEXES and CONFIG_PREEMPT_RT are mutually exclusive. At
most one of them can be set.
Cheers,
Longman