From: Frederic Weisbecker <frederic@xxxxxxxxxx>
The rcu_init() function is called way before SMP is initialized and
therefore only the boot CPU should be online at this stage.
Simplify the boot per-cpu initialization accordingly.
Signed-off-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
Cc: Neeraj Upadhyay <quic_neeraju@xxxxxxxxxxx>
Cc: Uladzislau Rezki <uladzislau.rezki@xxxxxxxx>
Cc: Joel Fernandes <joel@xxxxxxxxxxxxxxxxx>
Cc: Boqun Feng <boqun.feng@xxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
---
kernel/rcu/tree.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index a4b8189455d5..e6a9e5744e45 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -4782,7 +4782,7 @@ static void __init kfree_rcu_batch_init(void)
void __init rcu_init(void)
{
- int cpu;
+ int cpu = smp_processor_id();
rcu_early_boot_tests();
@@ -4802,11 +4802,10 @@ void __init rcu_init(void)
* or the scheduler are operational.
*/
pm_notifier(rcu_pm_notify, 0);
- for_each_online_cpu(cpu) {
- rcutree_prepare_cpu(cpu);
- rcu_cpu_starting(cpu);
- rcutree_online_cpu(cpu);
- }
+ WARN_ON(num_online_cpus() > 1); // Only one CPU this early in boot.
+ rcutree_prepare_cpu(cpu);
+ rcu_cpu_starting(cpu);
+ rcutree_online_cpu(cpu);
/* Create workqueue for Tree SRCU and for expedited GPs. */
rcu_gp_wq = alloc_workqueue("rcu_gp", WQ_MEM_RECLAIM, 0);
--
2.31.1.189.g2e36527f23
