[PATCH v3 03/11] devm-helpers: introduce devm_mutex_init

[Andy Shevchenko]

On Thu, Dec 14, 2023 at 12:30 AM George Stark <gnstark at salutedevices.com> wrote:
>
> 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 wrapper.
> 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() is
> extended so introduce devm_mutex_init().

...

> +#ifdef mutex_destroy
> +static inline void devm_mutex_release(void *res)
> +{
> +       mutex_destroy(res);
> +}
> +#endif
> +
> +/**
> + * devm_mutex_init - Resource-managed mutex initialization
> + * @dev:       Device which lifetime mutex is bound to
> + * @lock:      Pointer to a mutex
> + *
> + * Initialize mutex which is automatically destroyed when the driver is detached.
> + *
> + * Returns: 0 on success or a negative error code on failure.
> + */
> +static inline int devm_mutex_init(struct device *dev, struct mutex *lock)
> +{
> +       mutex_init(lock);
> +#ifdef mutex_destroy
> +       return devm_add_action_or_reset(dev, devm_mutex_release, lock);
> +#else
> +       return 0;
> +#endif
> +}

If this is going to be accepted, you may decrease the amount of ifdeffery.

#ifdef ...
#else
#define devm_mutex_init(dev, lock)  mutex_init(lock)
#endif


-- 
With Best Regards,
Andy Shevchenko