[PATCH v2] score: Fix _Thread_Change_priority()

[Sebastian Huber]

----- Joel Sherrill <joel.sherrill at oarcorp.com> schrieb:
> 
> 
> On 3/18/2015 3:20 PM, Sebastian Huber wrote:
[...]
> > diff --git a/cpukit/score/src/threadchangepriority.c b/cpukit/score/src/threadchangepriority.c
> > index d61dfb8..6ee65f5 100644
> > --- a/cpukit/score/src/threadchangepriority.c
> > +++ b/cpukit/score/src/threadchangepriority.c
> > @@ -29,29 +29,36 @@ void _Thread_Change_priority(
> >    bool              prepend_it
> >  )
> >  {
> > +  ISR_Level level;
> > +
> > +  _ISR_Disable( level );
> > +
> >    /*
> >     *  Do not bother recomputing all the priority related information if
> >     *  we are not REALLY changing priority.
> >     */
> >    if ( the_thread->current_priority != new_priority ) {
> > -    ISR_Level level;
> > -
> > -    _ISR_Disable( level );
> > +    uint32_t my_generation = the_thread->priority_generation + 1;
> >
> >      the_thread->current_priority = new_priority;
> > +    the_thread->priority_generation = my_generation;
> >
> > -    if ( _States_Is_ready( the_thread->current_state ) ) {
> > -      _Scheduler_Change_priority(
> > -        the_thread,
> > -        new_priority,
> > -        prepend_it
> > -      );
> > -    } else {
> > -      _Scheduler_Update_priority( the_thread, new_priority );
> > -    }
> > +    _Thread_queue_Requeue( the_thread->Wait.queue, the_thread );
> Can we get a comment above this call that _Thread_queue_Requeue
> checks that the thread is actually blocked on the specified queue so
> we don't need to check the thread state?

I want to get rid of this _Thread_queue_Requeue() in a follow up patch.  Things are getting much more compilicated on SMP since we now have to take the lock order into account to avoid deadlocks.