2020-08-23 03:06:40

by Laurent Pinchart

[permalink] [raw]
Subject: [PATCH] rcu-tasks: Fix compilation warning with !CONFIG_TASKS_RCU and CONFIG_TINY_RCU

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 <[email protected]>
---
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 */
--
Regards,

Laurent Pinchart


2020-08-25 15:05:30

by Paul E. McKenney

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

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 <[email protected]>
> ---
> 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?

Thanx, Paul

------------------------------------------------------------------------

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

2020-08-25 15:26:12

by Laurent Pinchart

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

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 <[email protected]>
> > ---
> > 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

2020-08-25 16:18:03

by Paul E. McKenney

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

On Tue, Aug 25, 2020 at 06:22:49PM +0300, Laurent Pinchart wrote:
> 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 <[email protected]>
> > > ---
> > > 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 :-)

This is admittedly an odd .h file, given that it is included but once.

I have applied the following patch with your Reported-by, cc-ing -stable
for v5.8 and later.

Thanx, Paul

> > ------------------------------------------------------------------------
> >
> > 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

2020-09-17 22:28:32

by Laurent Pinchart

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

Hi Paul,

On Tue, Aug 25, 2020 at 09:16:29AM -0700, Paul E. McKenney wrote:
> On Tue, Aug 25, 2020 at 06:22:49PM +0300, Laurent Pinchart wrote:
> > 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 <[email protected]>
> > > > ---
> > > > 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 :-)
>
> This is admittedly an odd .h file, given that it is included but once.
>
> I have applied the following patch with your Reported-by, cc-ing -stable
> for v5.8 and later.

I don't see the fix in Linus' master branch. Given that 8344496e8b49 was
introduced in v5.9-rc1, shouldn't this be treated as a regression and
merged before Linus releases v5.9 ?

> > > ------------------------------------------------------------------------
> > >
> > > 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

2020-09-17 23:27:56

by Paul E. McKenney

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

On Fri, Sep 18, 2020 at 01:26:41AM +0300, Laurent Pinchart wrote:
> Hi Paul,
>
> On Tue, Aug 25, 2020 at 09:16:29AM -0700, Paul E. McKenney wrote:
> > On Tue, Aug 25, 2020 at 06:22:49PM +0300, Laurent Pinchart wrote:
> > > 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 <[email protected]>
> > > > > ---
> > > > > 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 :-)
> >
> > This is admittedly an odd .h file, given that it is included but once.
> >
> > I have applied the following patch with your Reported-by, cc-ing -stable
> > for v5.8 and later.
>
> I don't see the fix in Linus' master branch. Given that 8344496e8b49 was
> introduced in v5.9-rc1, shouldn't this be treated as a regression and
> merged before Linus releases v5.9 ?

The current plan is that it goes in during the upcoming merge window,
a few weeks from now. However, it sounds like you need it sooner.
I will try doing a pull request and see what happens.

Thanx, Paul

> > > > ------------------------------------------------------------------------
> > > >
> > > > 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

2020-09-21 19:38:58

by Paul E. McKenney

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

On Thu, Sep 17, 2020 at 04:24:16PM -0700, Paul E. McKenney wrote:
> On Fri, Sep 18, 2020 at 01:26:41AM +0300, Laurent Pinchart wrote:
> > Hi Paul,
> >
> > On Tue, Aug 25, 2020 at 09:16:29AM -0700, Paul E. McKenney wrote:
> > > On Tue, Aug 25, 2020 at 06:22:49PM +0300, Laurent Pinchart wrote:
> > > > 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 <[email protected]>
> > > > > > ---
> > > > > > 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 :-)
> > >
> > > This is admittedly an odd .h file, given that it is included but once.
> > >
> > > I have applied the following patch with your Reported-by, cc-ing -stable
> > > for v5.8 and later.
> >
> > I don't see the fix in Linus' master branch. Given that 8344496e8b49 was
> > introduced in v5.9-rc1, shouldn't this be treated as a regression and
> > merged before Linus releases v5.9 ?
>
> The current plan is that it goes in during the upcoming merge window,
> a few weeks from now. However, it sounds like you need it sooner.
> I will try doing a pull request and see what happens.

And sent, CCing you.

Thanx, Paul

> > > > > ------------------------------------------------------------------------
> > > > >
> > > > > 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

2020-09-21 19:59:15

by Laurent Pinchart

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

On Mon, Sep 21, 2020 at 12:37:18PM -0700, Paul E. McKenney wrote:
> On Thu, Sep 17, 2020 at 04:24:16PM -0700, Paul E. McKenney wrote:
> > On Fri, Sep 18, 2020 at 01:26:41AM +0300, Laurent Pinchart wrote:
> > > Hi Paul,
> > >
> > > On Tue, Aug 25, 2020 at 09:16:29AM -0700, Paul E. McKenney wrote:
> > > > On Tue, Aug 25, 2020 at 06:22:49PM +0300, Laurent Pinchart wrote:
> > > > > 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 <[email protected]>
> > > > > > > ---
> > > > > > > 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 :-)
> > > >
> > > > This is admittedly an odd .h file, given that it is included but once.
> > > >
> > > > I have applied the following patch with your Reported-by, cc-ing -stable
> > > > for v5.8 and later.
> > >
> > > I don't see the fix in Linus' master branch. Given that 8344496e8b49 was
> > > introduced in v5.9-rc1, shouldn't this be treated as a regression and
> > > merged before Linus releases v5.9 ?
> >
> > The current plan is that it goes in during the upcoming merge window,
> > a few weeks from now. However, it sounds like you need it sooner.
> > I will try doing a pull request and see what happens.
>
> And sent, CCing you.

Thank you :-)

> > > > > > ------------------------------------------------------------------------
> > > > > >
> > > > > > 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