From b6fe4917ae4353b397079902cb024ae01f20dfb2 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 4 Aug 2022 13:46:05 -0700 Subject: rcu: Add full-sized polling for cond_sync_full() The cond_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 yet another member of the full-state RCU grace-period polling API, which is the cond_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. [ paulmck: Apply feedback from kernel test robot and Julia Lawall. ] Signed-off-by: Paul E. McKenney --- include/linux/rcutiny.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/linux/rcutiny.h') diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index 653e35777a99..3bee97f76bf4 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -44,6 +44,11 @@ static inline void cond_synchronize_rcu(unsigned long oldstate) might_sleep(); } +static inline void cond_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp) +{ + cond_synchronize_rcu(rgosp->rgos_norm); +} + static inline unsigned long start_poll_synchronize_rcu_expedited(void) { return start_poll_synchronize_rcu(); -- cgit v1.2.3-73-gaa49b