Le 07/03/2024 à 03:40, 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 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() > > Signed-off-by: George Stark <gnstark@xxxxxxxxxxxxxxxxx> > Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx> > --- > Hello Christophe. Hope you don't mind I put you SoB tag because you helped alot > to make this patch happen. Up to you, I sent a RFC patch based on yours with my ideas included because an exemple is easier than a lot of words for understanding, and my scripts automatically sets the Signed-off-by: but feel free to change it to Suggested-by: Christophe > > include/linux/mutex.h | 13 +++++++++++++ > kernel/locking/mutex-debug.c | 22 ++++++++++++++++++++++ > 2 files changed, 35 insertions(+) > > diff --git a/include/linux/mutex.h b/include/linux/mutex.h > index f7611c092db7..9bcf72cb941a 100644 > --- a/include/linux/mutex.h > +++ b/include/linux/mutex.h > @@ -22,6 +22,8 @@ > #include <linux/cleanup.h> > #include <linux/mutex_types.h> > > +struct device; > + > #ifdef CONFIG_DEBUG_LOCK_ALLOC > # define __DEP_MAP_MUTEX_INITIALIZER(lockname) \ > , .dep_map = { \ > @@ -115,10 +117,21 @@ do { \ > > #ifdef CONFIG_DEBUG_MUTEXES > > +int devm_mutex_init(struct device *dev, struct mutex *lock); > void mutex_destroy(struct mutex *lock); > > #else > > +static inline int devm_mutex_init(struct device *dev, struct mutex *lock) > +{ > + /* > + * since mutex_destroy is nop actually there's no need to register it > + * in devm subsystem. > + */ > + mutex_init(lock); > + return 0; > +} > + > static inline void mutex_destroy(struct mutex *lock) {} > > #endif > diff --git a/kernel/locking/mutex-debug.c b/kernel/locking/mutex-debug.c > index bc8abb8549d2..c9efab1a8026 100644 > --- a/kernel/locking/mutex-debug.c > +++ b/kernel/locking/mutex-debug.c > @@ -19,6 +19,7 @@ > #include <linux/kallsyms.h> > #include <linux/interrupt.h> > #include <linux/debug_locks.h> > +#include <linux/device.h> > > #include "mutex.h" > > @@ -104,3 +105,24 @@ void mutex_destroy(struct mutex *lock) > } > > EXPORT_SYMBOL_GPL(mutex_destroy); > + > +static void devm_mutex_release(void *res) > +{ > + mutex_destroy(res); > +} > + > +/** > + * 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. > + */ > +int devm_mutex_init(struct device *dev, struct mutex *lock) > +{ > + mutex_init(lock); > + return devm_add_action_or_reset(dev, devm_mutex_release, lock); > +} > +EXPORT_SYMBOL_GPL(devm_mutex_init); > -- > 2.25.1 >
