From 57b23c0f612dcfa1aae99c9422d6d36ced1670d4 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Tue, 7 Apr 2026 18:22:33 +0200 Subject: bpf: Retire rcu_trace_implies_rcu_gp() RCU Tasks Trace grace period implies RCU grace period, and this guarantee is expected to remain in the future. Only BPF is the user of this predicate, hence retire the API and clean up all in-tree users. RCU Tasks Trace is now implemented on SRCU-fast and its grace period mechanism always has at least one call to synchronize_rcu() as it is required for SRCU-fast's correctness (it replaces the smp_mb() that SRCU-fast readers skip). So, RCU-tt GP will always imply RCU GP. Reviewed-by: Puranjay Mohan Reviewed-by: Paul E. McKenney Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260407162234.785270-1-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- include/linux/rcupdate.h | 12 ------------ 1 file changed, 12 deletions(-) (limited to 'include/linux') diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 04f3f86a4145..bfa765132de8 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -205,18 +205,6 @@ static inline void exit_tasks_rcu_start(void) { } static inline void exit_tasks_rcu_finish(void) { } #endif /* #else #ifdef CONFIG_TASKS_RCU_GENERIC */ -/** - * rcu_trace_implies_rcu_gp - does an RCU Tasks Trace grace period imply an RCU grace period? - * - * As an accident of implementation, an RCU Tasks Trace grace period also - * acts as an RCU grace period. However, this could change at any time. - * Code relying on this accident must call this function to verify that - * this accident is still happening. - * - * You have been warned! - */ -static inline bool rcu_trace_implies_rcu_gp(void) { return true; } - /** * cond_resched_tasks_rcu_qs - Report potential quiescent states to RCU * -- cgit v1.2.3