Simply checking if the segcblist is enabled is enough to know if we need to initialize it or not. It's safe to check within hotplug machine.
Signed-off-by: Frederic Weisbecker <[email protected]> Cc: Josh Triplett <[email protected]> Cc: Lai Jiangshan <[email protected]> Cc: Joel Fernandes <[email protected]> Cc: Neeraj Upadhyay <[email protected]> Cc: Boqun Feng <[email protected]> --- kernel/rcu/tree.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 4c5a1ac54fa6..f74a9ba62c12 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -4066,14 +4066,13 @@ int rcutree_prepare_cpu(unsigned int cpu) rdp->dynticks_nesting = 1; /* CPU not up, no tearing. */ rcu_dynticks_eqs_online(); raw_spin_unlock_rcu_node(rnp); /* irqs remain disabled. */ + /* - * Lock in case the CB/GP kthreads are still around handling - * old callbacks. + * Only non-NOCB CPUs that didn't have early-boot callbacks need to be + * (re-)initialized. */ - rcu_nocb_lock(rdp); - if (rcu_segcblist_empty(&rdp->cblist)) /* No early-boot CBs? */ + if (!rcu_segcblist_is_enabled(&rdp->cblist)) rcu_segcblist_init(&rdp->cblist); /* Re-enable callbacks. */ - rcu_nocb_unlock(rdp); /* * Add CPU to leaf rcu_node pending-online bitmask. Any needed -- 2.25.1
