mutex_destroy is no-op inline when DEBUG_MUTEX is not enabled. When mutex_destroy is indirectly used by non-GPL kernel modules that use inline functions such as reservation_object_fini(), users can use a kernel with DEBUG_MUTEX disabled to avoid a dependence on the GPL-only symbol mutex_destroy.
The RT Linux patches replace mutex_destroy with rt_mutex_destroy. Currently, rt_mutex_destroy is GPL_ONLY irrespective of whether mutex debugging is enabled. This patch aligns rt_mutex_destroy with mutex_destroy by using the same no-op inline technique. This allows non-GPL modules to access the same functionality with RT Linux as with regular Linux. Signed-off-by: Alex Goins <ago...@nvidia.com> --- include/linux/rtmutex.h | 7 ++++++- kernel/locking/rtmutex.c | 5 ++--- 2 files changed, 8 insertions(+), 4 deletions(-) diff --git a/include/linux/rtmutex.h b/include/linux/rtmutex.h index 1abba5c..741e844 100644 --- a/include/linux/rtmutex.h +++ b/include/linux/rtmutex.h @@ -56,6 +56,12 @@ struct hrtimer_sleeper; #endif #ifdef CONFIG_DEBUG_RT_MUTEXES + extern void rt_mutex_destroy(struct rt_mutex *lock); +#else + static inline void rt_mutex_destroy(struct rt_mutex *lock) {} +#endif + +#ifdef CONFIG_DEBUG_RT_MUTEXES # define __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \ , .name = #mutexname, .file = __FILE__, .line = __LINE__ # define rt_mutex_init(mutex) __rt_mutex_init(mutex, __func__) @@ -87,7 +93,6 @@ static inline int rt_mutex_is_locked(struct rt_mutex *lock) } extern void __rt_mutex_init(struct rt_mutex *lock, const char *name); -extern void rt_mutex_destroy(struct rt_mutex *lock); extern void rt_mutex_lock(struct rt_mutex *lock); extern int rt_mutex_lock_interruptible(struct rt_mutex *lock); diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c index 1ec0f48..8d3a80e 100644 --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -1513,6 +1513,7 @@ bool __sched rt_mutex_futex_unlock(struct rt_mutex *lock, return rt_mutex_slowunlock(lock, wqh); } +#ifdef CONFIG_DEBUG_RT_MUTEXES /** * rt_mutex_destroy - mark a mutex unusable * @lock: the mutex to be destroyed @@ -1524,12 +1525,10 @@ bool __sched rt_mutex_futex_unlock(struct rt_mutex *lock, void rt_mutex_destroy(struct rt_mutex *lock) { WARN_ON(rt_mutex_is_locked(lock)); -#ifdef CONFIG_DEBUG_RT_MUTEXES lock->magic = NULL; -#endif } - EXPORT_SYMBOL_GPL(rt_mutex_destroy); +#endif /** * __rt_mutex_init - initialize the rt lock -- 1.9.1