Re: [PATCH rcu 10/11] srcu: Add FORCE_NEED_SRCU_NMI_SAFE Kconfig for testing

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@kernel.org wrote:

...

commit 2245ef8605a80726548253d885b4cadd97f69f3b Author: Paul E. McKenney paulmck@kernel.org 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@linux-m68k.org>
Closes: https://lore.kernel.org/all/CAMuHMdX6dy9_tmpLkpcnGzxyRbe6qSWYukcPp=H1GzZdyd3qBQ@mail.gmail.com/
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

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@linux-m68k.org

Applied, and thank you very much for both the review and the report!

Thanx, Paul