From 76ea364161e72b1878126edf8d507d2a62fb47b0 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 2 Aug 2022 17:04:54 -0700 Subject: rcu: Add full-sized polling for start_poll() The start_poll_synchronize_rcu() API compresses the combined expedited and normal grace-period states into a single unsigned long, which conserves storage, but can miss grace periods in certain cases involving overlapping normal and expedited grace periods. Missing the occasional grace period is usually not a problem, but there are use cases that care about each and every grace period. This commit therefore adds the next member of the full-state RCU grace-period polling API, namely the start_poll_synchronize_rcu_full() function. This uses up to three times the storage (rcu_gp_oldstate structure instead of unsigned long), but is guaranteed not to miss grace periods. Signed-off-by: Paul E. McKenney --- include/linux/rcutiny.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'include/linux/rcutiny.h') diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index 6e299955c4e9..6bc30e46a819 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -26,6 +26,12 @@ static inline void get_state_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp) } unsigned long start_poll_synchronize_rcu(void); + +static inline void start_poll_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp) +{ + rgosp->rgos_norm = start_poll_synchronize_rcu(); +} + bool poll_state_synchronize_rcu(unsigned long oldstate); static inline bool poll_state_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp) -- cgit v1.2.3-73-gaa49b