Re: [PATCH] rcu-tasks: Fix compilation warning with !CONFIG_TASKS_RCU and CONFIG_TINY_RCU

[Laurent Pinchart]

Hi Paul,

On Tue, Aug 25, 2020 at 08:02:22AM -0700, Paul E. McKenney wrote:
> On Sun, Aug 23, 2020 at 06:04:05AM +0300, Laurent Pinchart wrote:
> > Commit 8344496e8b49 ("rcu-tasks: Conditionally compile
> > show_rcu_tasks_gp_kthreads()") introduced conditional compilation of
> > several functions, but forgot one occurrence of
> > show_rcu_tasks_classic_gp_kthread() that causes the compiler to warn of
> > an unused static function. Fix it.
> > 
> > Fixes: 8344496e8b49 ("rcu-tasks: Conditionally compile show_rcu_tasks_gp_kthreads()")
> > Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> > ---
> >  kernel/rcu/tasks.h | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
> > index 835e2df8590a..bddf3968c1eb 100644
> > --- a/kernel/rcu/tasks.h
> > +++ b/kernel/rcu/tasks.h
> > @@ -590,7 +590,9 @@ void exit_tasks_rcu_finish(void) __releases(&tasks_rcu_exit_srcu)
> >  }
> >  
> >  #else /* #ifdef CONFIG_TASKS_RCU */
> > +#ifndef CONFIG_TINY_RCU
> >  static void show_rcu_tasks_classic_gp_kthread(void) { }
> > +#endif /* #ifndef CONFIG_TINY_RCU */
> >  void exit_tasks_rcu_start(void) { }
> >  void exit_tasks_rcu_finish(void) { exit_tasks_rcu_finish_trace(current); }
> >  #endif /* #else #ifdef CONFIG_TASKS_RCU */
> 
> Good catch!!!
> 
> But does the following addition of "static inline" work for you?

They do. I initially added a static inline, and realized #ifdef was used
extensively when trying to find the proper Fixes: tag, so I went for
that. I don't mind either way, as long as this gets fixed :-)

> ------------------------------------------------------------------------
> 
> diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
> index 835e2df..3dc3ffc 100644
> --- a/kernel/rcu/tasks.h
> +++ b/kernel/rcu/tasks.h
> @@ -590,9 +590,9 @@ void exit_tasks_rcu_finish(void) __releases(&tasks_rcu_exit_srcu)
>  }
>  
>  #else /* #ifdef CONFIG_TASKS_RCU */
> -static void show_rcu_tasks_classic_gp_kthread(void) { }
> -void exit_tasks_rcu_start(void) { }
> -void exit_tasks_rcu_finish(void) { exit_tasks_rcu_finish_trace(current); }
> +static inline void show_rcu_tasks_classic_gp_kthread(void) { }
> +static inline void exit_tasks_rcu_start(void) { }
> +static inline void exit_tasks_rcu_finish(void) { exit_tasks_rcu_finish_trace(current); }
>  #endif /* #else #ifdef CONFIG_TASKS_RCU */
>  
>  #ifdef CONFIG_TASKS_RUDE_RCU

-- 
Regards,

Laurent Pinchart