On Mon, Jun 05, 2017 at 03:09:50PM -0700, Paul E. McKenney wrote: > diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c > index 3ae8474557df..157654fa436a 100644 > --- a/kernel/rcu/srcutree.c > +++ b/kernel/rcu/srcutree.c > @@ -357,7 +357,7 @@ EXPORT_SYMBOL_GPL(cleanup_srcu_struct); > > /* > * Counts the new reader in the appropriate per-CPU element of the > - * srcu_struct. Must be called from process context. > + * srcu_struct. > * Returns an index that must be passed to the matching srcu_read_unlock(). > */ > int __srcu_read_lock(struct srcu_struct *sp) > @@ -365,7 +365,7 @@ int __srcu_read_lock(struct srcu_struct *sp) > int idx; > > idx = READ_ONCE(sp->srcu_idx) & 0x1; > - __this_cpu_inc(sp->sda->srcu_lock_count[idx]); > + this_cpu_inc(sp->sda->srcu_lock_count[idx]); > smp_mb(); /* B */ /* Avoid leaking the critical section. */ > return idx; > } So again, the change is to make this an IRQ safe operation, however if we have this balance requirement, the IRQ will not visibly change the value and load-store should be good again, no? Or am I missing some other detail with this implementation?
