rcu: Make rcu_read_unlock_special() expedite strict grace periods

In kernels built with CONFIG_RCU_STRICT_GRACE_PERIOD=y, every grace
period is an expedited grace period.  However, rcu_read_unlock_special()
does not treat them that way, instead allowing the deferred quiescent
state to be reported whenever.  This commit therefore adds a check of
this Kconfig option that causes rcu_read_unlock_special() to treat all
grace periods as expedited for CONFIG_RCU_STRICT_GRACE_PERIOD=y kernels.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index e17cb23..a21c41c 100644 (file)
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -615,6 +615,7 @@ static void rcu_read_unlock_special(struct task_struct *t)
 
                expboost = (t->rcu_blocked_node && READ_ONCE(t->rcu_blocked_node->exp_tasks)) ||
                           (rdp->grpmask & READ_ONCE(rnp->expmask)) ||
+                          IS_ENABLED(CONFIG_RCU_STRICT_GRACE_PERIOD) ||
                           (IS_ENABLED(CONFIG_RCU_BOOST) && irqs_were_disabled &&
                            t->rcu_blocked_node);
                // Need to defer quiescent state until everything is enabled.