Re: [PATCH rcu 10/11] srcu: Add FORCE_NEED_SRCU_NMI_SAFE Kconfig for testing
From: Paul E. McKenney
Date: Tue Mar 25 2025 - 11:51:15 EST
On Tue, Mar 25, 2025 at 04:36:23PM +0100, Geert Uytterhoeven wrote:
> Hi Paul,
>
> On Tue, 25 Mar 2025 at 16:08, Paul E. McKenney <paulmck@xxxxxxxxxx> wrote:
> > commit 2245ef8605a80726548253d885b4cadd97f69f3b
> > Author: Paul E. McKenney <paulmck@xxxxxxxxxx>
> > Date: Tue Mar 25 07:31:45 2025 -0700
> >
> > srcu: Make FORCE_NEED_SRCU_NMI_SAFE depend on RCU_EXPERT
> >
> > The FORCE_NEED_SRCU_NMI_SAFE is useful only for those wishing to test
> > the SRCU code paths that accommodate architectures that do not have
> > NMI-safe per-CPU operations, that is, those architectures that do not
> > select the ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option. As such, this
> > is a specialized Kconfig option that is not intended for casual users.
> >
> > This commit therefore hides it behind the RCU_EXPERT Kconfig option.
> > Given that this new FORCE_NEED_SRCU_NMI_SAFE Kconfig option has no effect
> > unless the ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option is also selected,
> > it also depends on this Kconfig option.
> >
> > [ paulmck: Apply Geert Uytterhoeven feedback. ]
> >
> > Reported-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
> > Closes: https://lore.kernel.org/all/CAMuHMdX6dy9_tmpLkpcnGzxyRbe6qSWYukcPp=H1GzZdyd3qBQ@xxxxxxxxxxxxxx/
> > Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
> >
> > diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig
> > index b3f985d41717a..ceaf6594f634c 100644
> > --- a/kernel/rcu/Kconfig
> > +++ b/kernel/rcu/Kconfig
> > @@ -68,6 +68,8 @@ config TREE_SRCU
> > config FORCE_NEED_SRCU_NMI_SAFE
> > bool "Force selection of NEED_SRCU_NMI_SAFE"
> > depends on !TINY_SRCU
> > + depends on RCU_EXPERT
> > + depends on ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
> > select NEED_SRCU_NMI_SAFE
> > default n
> > help
>
> LGTM, so
> Reviewed-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Applied, and thank you very much for both the review and the report!
Thanx, Paul