From 4cd47222e435dec8e3787614924174f53fcfb5ae Mon Sep 17 00:00:00 2001 From: George Stark Date: Thu, 11 Apr 2024 19:10:25 +0300 Subject: locking/mutex: Introduce devm_mutex_init() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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(). Suggested-by: Christophe Leroy Signed-off-by: George Stark Reviewed-by: Christophe Leroy Reviewed-by: Andy Shevchenko Reviewed-by: Marek Behún Acked-by: Waiman Long Link: https://lore.kernel.org/r/20240411161032.609544-2-gnstark@salutedevices.com Signed-off-by: Lee Jones --- include/linux/mutex.h | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) (limited to 'include/linux/mutex.h') diff --git a/include/linux/mutex.h b/include/linux/mutex.h index 67edc4ca2bee..a561c629d89f 100644 --- a/include/linux/mutex.h +++ b/include/linux/mutex.h @@ -22,6 +22,8 @@ #include #include +struct device; + #ifdef CONFIG_DEBUG_LOCK_ALLOC # define __DEP_MAP_MUTEX_INITIALIZER(lockname) \ , .dep_map = { \ @@ -117,6 +119,31 @@ do { \ } while (0) #endif /* CONFIG_PREEMPT_RT */ +#ifdef CONFIG_DEBUG_MUTEXES + +int __devm_mutex_init(struct device *dev, struct mutex *lock); + +#else + +static inline int __devm_mutex_init(struct device *dev, struct mutex *lock) +{ + /* + * When CONFIG_DEBUG_MUTEXES is off mutex_destroy() is just a nop so + * no really need to register it in the devm subsystem. + */ + return 0; +} + +#endif + +#define devm_mutex_init(dev, mutex) \ +({ \ + typeof(mutex) mutex_ = (mutex); \ + \ + mutex_init(mutex_); \ + __devm_mutex_init(dev, mutex_); \ +}) + /* * See kernel/locking/mutex.c for detailed documentation of these APIs. * Also see Documentation/locking/mutex-design.rst. -- cgit v1.2.3