Re: [PATCH] Real-Time Preemption V0.7.52-07: rt_init_MUTEX_LOCKED declaration

[Ingo Molnar <mingo@elte.hu>]

* Luca Falavigna <dktrkranz@gmail.com> wrote:

> This patch fixes broken rt_init_MUTEX_LOCKED declaration using 
> rt_sema_init() macro. This way we fix a potential compile bug: 
> rt_init_MUTEX_LOCKED calls 
> there_is_no_init_MUTEX_LOCKED_for_RT_semaphores, which is not 
> referenced. (e.g. drivers/char/watchdog/cpu5wdt.c: "cpu5wdt: Unknown 
> symbol there_is_no_init_MUTEX_LOCKED_for_RT_semaphores")

the right solution would be to mark policy->lock as a compat_semaphore.  
That will revert things back to the stock semantics. (at the price of 
not having PI, which isnt a big issue in this case.)

> -+extern void there_is_no_init_MUTEX_LOCKED_for_RT_semaphores(void);

the reason for not allowing init_MUTEX_LOCKED() is that in basically 
every case that does it, the semaphore is not used as a true mutex in 
the strict sense. So the affected semaphore should be changed to 
compat_semaphore, to gain full semantics.

	Ingo