From 395e73bd8d35fa9b8505e44f63a2a10abde09cce Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Sun, 9 Jun 2024 20:12:19 -0700 Subject: [PATCH] srcu: Add NUM_ACTIVE_SRCU_POLL_OLDSTATE This commit adds NUM_ACTIVE_SRCU_POLL_OLDSTATE, which gives the maximum number of distinct return values from get_state_synchronize_rcu() that can, at a given point in time, correspond to not-completed SRCU grace periods. Reported-by: Kent Overstreet Closes: https://lore.kernel.org/all/irycqy4sinjdgm2hkyix2bffunpcmuwgeufsx6nlljvqme3wiu@ify3zdnrmzph/ Signed-off-by: Paul E. McKenney --- include/linux/srcu.h | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/include/linux/srcu.h b/include/linux/srcu.h index 236610e4a8fa..f664cba7a80c 100644 --- a/include/linux/srcu.h +++ b/include/linux/srcu.h @@ -61,6 +61,10 @@ unsigned long get_state_synchronize_srcu(struct srcu_struct *ssp); unsigned long start_poll_synchronize_srcu(struct srcu_struct *ssp); bool poll_state_synchronize_srcu(struct srcu_struct *ssp, unsigned long cookie); +// Maximum number of unsigned long values corresponding to +// not-yet-completed SRCU grace periods. +#define NUM_ACTIVE_SRCU_POLL_OLDSTATE 2 + #ifdef CONFIG_NEED_SRCU_NMI_SAFE int __srcu_read_lock_nmisafe(struct srcu_struct *ssp) __acquires(ssp); void __srcu_read_unlock_nmisafe(struct srcu_struct *ssp, int idx) __releases(ssp); -- 2.50.1