[18/48] rcu: Make TINY_RCU depend on !PREEMPT_RCU rather than !PREEMPTION

Commit Message

Uladzislau Rezki May 7, 2024, 9:35 a.m. UTC

From: "Paul E. McKenney" <[e-mail]>

Right now, TINY_RCU depends on (!PREEMPTION && !SMP), which has served the
kernel well for many years due to the fact that PREEMPT_RCU is normally
a synonym for PREEMPTION.  But with the advent of lazy preemption,
it will be possible to have non-preemptible RCU in a preemptible kernel,
so that kernels could be built with PREEMPT_RCU=n and PREEMPTION=y.

This commit therefore makes TINY_RCU depend on (!PREEMPT_RCU && !SMP),
thus allowing for a non-preemptible RCU in preemptible kernels.

Signed-off-by: Paul E. McKenney <[e-mail]>
Cc: Ankur Arora <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Signed-off-by: Uladzislau Rezki (Sony) <[e-mail]>
---
 kernel/rcu/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Patch

diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig
index e7d2dd267593..7dca0138260c 100644
--- a/kernel/rcu/Kconfig
+++ b/kernel/rcu/Kconfig
@@ -31,7 +31,7 @@  config PREEMPT_RCU
 
 config TINY_RCU
 	bool
-	default y if !PREEMPTION && !SMP
+	default y if !PREEMPT_RCU && !SMP
 	help
 	  This option selects the RCU implementation that is
 	  designed for UP systems from which real-time response