Re: [PATCH v2] srcu/tiny: Remove preempt_disable/enable() in srcu_gp_start_if_needed()

Joel Fernandes
2025-09-10T14:36:25Z

[..]
> > kernel/rcu/srcutiny.c | 4 +---
> > 1 file changed, 1 insertion(+), 3 deletions(-)
> >
> > diff --git a/kernel/rcu/srcutiny.c b/kernel/rcu/srcutiny.c
> > index b52ec45698e8..b2da188133fc 100644
> > --- a/kernel/rcu/srcutiny.c
> > +++ b/kernel/rcu/srcutiny.c
> > @@ -181,10 +181,9 @@ static void srcu_gp_start_if_needed(struct srcu_struct *ssp)
> > {
> > unsigned long cookie;
> >
> > - preempt_disable(); // Needed for PREEMPT_LAZY
> > + lockdep_assert_preemption_disabled();

nit: Do we still want to keep the comment that the expectation of preemption
being disabled is for the LAZY case?

thanks,

- Joel

> > cookie = get_state_synchronize_srcu(ssp);
> > if (ULONG_CMP_GE(READ_ONCE(ssp->srcu_idx_max), cookie)) {
> > - preempt_enable();
> > return;
> > }
> > WRITE_ONCE(ssp->srcu_idx_max, cookie);
> > @@ -194,7 +193,6 @@ static void srcu_gp_start_if_needed(struct srcu_struct *ssp)
> > else if (list_empty(&ssp->srcu_work.entry))
> > list_add(&ssp->srcu_work.entry, &srcu_boot_list);
> > }
> > - preempt_enable();
> > }
> >
> > /*
> > --
> > 2.48.1
> >