Le 13/12/2023 à 23:30, George Stark a écrit : > [Vous ne recevez pas souvent de courriers de gnstark@xxxxxxxxxxxxxxxxx. Découvrez pourquoi ceci est important à https://aka.ms/LearnAboutSenderIdentification ] > > 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(). So you abandonned the idea of using mutex.h ? I can't see the point to spread mutex functions into devm-helpers.h Adding a mutex_destroy macro for this purpose looks odd. And if someone defines a new version of mutex_destroy() and forget the macro, it will go undetected. Usually macros of that type serve the purpose of defining a fallback when the macro is not defined. In that case, when someone adds a new version without defining the macro, it gets detected because if conflicts with the fallback. But in your case it works the other way round, so I will just go undetected. For me the best solution remains to use mutex.h and have devm_mutex_init() defined or declared at the same place as mutex_destroy(). > > Signed-off-by: George Stark <gnstark@xxxxxxxxxxxxxxxxx> > --- > include/linux/devm-helpers.h | 27 +++++++++++++++++++++++++++ > 1 file changed, 27 insertions(+) > > diff --git a/include/linux/devm-helpers.h b/include/linux/devm-helpers.h > index 74891802200d..4043c3481d2e 100644 > --- a/include/linux/devm-helpers.h > +++ b/include/linux/devm-helpers.h > @@ -24,6 +24,7 @@ > */ > > #include <linux/device.h> > +#include <linux/mutex.h> > #include <linux/workqueue.h> > > static inline void devm_delayed_work_drop(void *res) > @@ -76,4 +77,30 @@ static inline int devm_work_autocancel(struct device *dev, > return devm_add_action(dev, devm_work_drop, w); > } > > +#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 > +} > + > #endif > -- > 2.25.1 >
