+ George Stark (IIRC you also tried to achieve something like this in the past)
On Thu, Sep 5, 2024 at 11:47 PM Bart Van Assche <bvanassche@xxxxxxx> wrote:
>
> With CONFIG_PREEMPT_RT disabled __mutex_init() is a function. With
> CONFIG_PREEMPT_RT enabled, __mutex_init() is a macro. I assume this is why
> mutex_init() is defined twice as exactly the same macro.
>
> Prepare for introducing a new macro for mutex initialization by combining
> the two identical mutex_init() definitions into a single definition. This
> patch does not change any functionality because the C preprocessor expands
> macros when it encounters the macro name and not when a macro definition
> is encountered. See also commit bb630f9f7a7d ("locking/rtmutex: Add mutex
> variant for RT").
>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
> ---
> include/linux/mutex.h | 8 +-------
> 1 file changed, 1 insertion(+), 7 deletions(-)
>
> diff --git a/include/linux/mutex.h b/include/linux/mutex.h
> index a561c629d89f..ef617089db19 100644
> --- a/include/linux/mutex.h
> +++ b/include/linux/mutex.h
> @@ -49,7 +49,6 @@ static inline void mutex_destroy(struct mutex *lock) {}
>
> #endif
>
> -#ifndef CONFIG_PREEMPT_RT
> /**
> * mutex_init - initialize the mutex
> * @mutex: the mutex to be initialized
> @@ -65,6 +64,7 @@ do { \
> __mutex_init((mutex), #mutex, &__key); \
> } while (0)
>
> +#ifndef CONFIG_PREEMPT_RT
> #define __MUTEX_INITIALIZER(lockname) \
> { .owner = ATOMIC_LONG_INIT(0) \
> , .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(lockname.wait_lock) \
> @@ -111,12 +111,6 @@ do { \
> __mutex_rt_init((mutex), name, key); \
> } while (0)
>
> -#define mutex_init(mutex) \
> -do { \
> - static struct lock_class_key __key; \
> - \
> - __mutex_init((mutex), #mutex, &__key); \
> -} while (0)
> #endif /* CONFIG_PREEMPT_RT */
>
> #ifdef CONFIG_DEBUG_MUTEXES
--
With Best Regards,
Andy Shevchenko
