[PATCH rcu 03/12] rcutorture: Validate get_completed_synchronize_rcu()

Paul E. McKenney
2022-06-20T22:51:42Z

This commit verifies that the RCU grace-period state cookie returned
from get_completed_synchronize_rcu() causes poll_state_synchronize_rcu()
to return true, as required.

This commit is in preparation for polled expedited grace periods.

Link: https://lore.kernel.org/all/20220121142454.1994916-1-bfoster@redhat.com/
Link: https://docs.google.com/document/d/1RNKWW9jQyfjxw2E8dsXVTdvZYh0HnYeSHDKog9jhdN8/edit?usp=sharing
Cc: Brian Foster <bfoster@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Ian Kent <raven@themaw.net>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
kernel/rcu/rcutorture.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 7120165a93426..4ceec9f4169c7 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -338,6 +338,7 @@ struct rcu_torture_ops {
void (*sync)(void);
void (*exp_sync)(void);
unsigned long (*get_gp_state)(void);
+ unsigned long (*get_gp_completed)(void);
unsigned long (*start_gp_poll)(void);
bool (*poll_gp_state)(unsigned long oldstate);
void (*cond_sync)(unsigned long oldstate);
@@ -504,6 +505,7 @@ static struct rcu_torture_ops rcu_ops = {
.sync = synchronize_rcu,
.exp_sync = synchronize_rcu_expedited,
.get_gp_state = get_state_synchronize_rcu,
+ .get_gp_completed = get_completed_synchronize_rcu,
.start_gp_poll = start_poll_synchronize_rcu,
.poll_gp_state = poll_state_synchronize_rcu,
.cond_sync = cond_synchronize_rcu,
@@ -1254,6 +1256,10 @@ rcu_torture_writer(void *arg)
rcu_torture_writer_state_getname(),
rcu_torture_writer_state,
cookie, cur_ops->get_gp_state());
+ if (cur_ops->get_gp_completed) {
+ cookie = cur_ops->get_gp_completed();
+ WARN_ON_ONCE(!cur_ops->poll_gp_state(cookie));
+ }
cur_ops->readunlock(idx);
}
switch (synctype[torture_random(&rand) % nsynctypes]) {
--
2.31.1.189.g2e36527f23