From: Clark Williams Date: Sun, 30 Jan 2022 15:46:27 -0600 Subject: [PATCH 338/342] rt: PREEMPT_RT safety net for backported patches Origin: https://git.kernel.org/cgit/linux/kernel/git/rt/linux-stable-rt.git/commit?id=d7c847666d7341feb472045cb36e599fc76b63a6 While doing some 4.19-rt cleanup work, I stumbled across the fact that parts of two backported patches were dependent on CONFIG_PREEMPT_RT, rather than the CONFIG_PREEMPT_RT_FULL used in 4.19 and earlier RT series. The commits in the linux-stable-rt v4.19-rt branch are: dad4c6a33bf4e mm: slub: Don't resize the location tracking cache on PREEMPT_RT e626b6f873f2c net: Treat __napi_schedule_irqoff() as __napi_schedule() on PREEMPT_RT Discussing this at the Stable RT maintainers meeting, Steven Rostedt suggested that we automagically select CONFIG_PREEMPT_RT if CONFIG_PREEMPT_RT_FULL is on, giving us a safety net for any subsequently backported patches. Here's my first cut at that patch. I suspect we'll need a similar patch for stable RT kernels < 4.19. Suggested-by: Steven Rostedt Signed-off-by: Clark Williams --- kernel/Kconfig.preempt | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/Kconfig.preempt b/kernel/Kconfig.preempt index 306567f72a3e..fd924c0bcea7 100644 --- a/kernel/Kconfig.preempt +++ b/kernel/Kconfig.preempt @@ -6,6 +6,9 @@ config PREEMPT_RT_BASE bool select PREEMPT +config PREEMPT_RT + bool + config HAVE_PREEMPT_LAZY bool @@ -80,6 +83,7 @@ config PREEMPT_RT_FULL depends on IRQ_FORCED_THREADING select PREEMPT_RT_BASE select PREEMPT_RCU + select PREEMPT_RT help All and everything