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-rw-r--r--kernel/rcu/update.c38
1 files changed, 30 insertions, 8 deletions
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index f19271dce0a9..4f6db7e6a117 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -121,11 +121,14 @@ EXPORT_SYMBOL(rcu_read_lock_sched_held);
* Should expedited grace-period primitives always fall back to their
* non-expedited counterparts? Intended for use within RCU. Note
* that if the user specifies both rcu_expedited and rcu_normal, then
- * rcu_normal wins.
+ * rcu_normal wins. (Except during the time period during boot from
+ * when the first task is spawned until the rcu_exp_runtime_mode()
+ * core_initcall() is invoked, at which point everything is expedited.)
*/
bool rcu_gp_is_normal(void)
{
- return READ_ONCE(rcu_normal);
+ return READ_ONCE(rcu_normal) &&
+ rcu_scheduler_active != RCU_SCHEDULER_INIT;
}
EXPORT_SYMBOL_GPL(rcu_gp_is_normal);
@@ -135,13 +138,14 @@ static atomic_t rcu_expedited_nesting =
/*
* Should normal grace-period primitives be expedited? Intended for
* use within RCU. Note that this function takes the rcu_expedited
- * sysfs/boot variable into account as well as the rcu_expedite_gp()
- * nesting. So looping on rcu_unexpedite_gp() until rcu_gp_is_expedited()
- * returns false is a -really- bad idea.
+ * sysfs/boot variable and rcu_scheduler_active into account as well
+ * as the rcu_expedite_gp() nesting. So looping on rcu_unexpedite_gp()
+ * until rcu_gp_is_expedited() returns false is a -really- bad idea.
*/
bool rcu_gp_is_expedited(void)
{
- return rcu_expedited || atomic_read(&rcu_expedited_nesting);
+ return rcu_expedited || atomic_read(&rcu_expedited_nesting) ||
+ rcu_scheduler_active == RCU_SCHEDULER_INIT;
}
EXPORT_SYMBOL_GPL(rcu_gp_is_expedited);
@@ -257,7 +261,7 @@ EXPORT_SYMBOL_GPL(rcu_callback_map);
int notrace debug_lockdep_rcu_enabled(void)
{
- return rcu_scheduler_active && debug_locks &&
+ return rcu_scheduler_active != RCU_SCHEDULER_INACTIVE && debug_locks &&
current->lockdep_recursion == 0;
}
EXPORT_SYMBOL_GPL(debug_lockdep_rcu_enabled);
@@ -591,7 +595,7 @@ EXPORT_SYMBOL_GPL(call_rcu_tasks);
void synchronize_rcu_tasks(void)
{
/* Complain if the scheduler has not started. */
- RCU_LOCKDEP_WARN(!rcu_scheduler_active,
+ RCU_LOCKDEP_WARN(rcu_scheduler_active == RCU_SCHEDULER_INACTIVE,
"synchronize_rcu_tasks called too soon");
/* Wait for the grace period. */
@@ -813,6 +817,23 @@ static void rcu_spawn_tasks_kthread(void)
#endif /* #ifdef CONFIG_TASKS_RCU */
+/*
+ * Test each non-SRCU synchronous grace-period wait API. This is
+ * useful just after a change in mode for these primitives, and
+ * during early boot.
+ */
+void rcu_test_sync_prims(void)
+{
+ if (!IS_ENABLED(CONFIG_PROVE_RCU))
+ return;
+ synchronize_rcu();
+ synchronize_rcu_bh();
+ synchronize_sched();
+ synchronize_rcu_expedited();
+ synchronize_rcu_bh_expedited();
+ synchronize_sched_expedited();
+}
+
#ifdef CONFIG_PROVE_RCU
/*
@@ -865,6 +886,7 @@ void rcu_early_boot_tests(void)
early_boot_test_call_rcu_bh();
if (rcu_self_test_sched)
early_boot_test_call_rcu_sched();
+ rcu_test_sync_prims();
}
static int rcu_verify_early_boot_tests(void)