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SubjectRe: [PATCH v4 1/2] locking/rwsem: Add a new RWSEM_ANONYMOUSLY_OWNED flag

* Matthew Wilcox <willy@infradead.org> wrote:

> On Tue, May 15, 2018 at 05:49:50PM -0400, Waiman Long wrote:
> > @@ -357,11 +357,8 @@ static inline bool rwsem_can_spin_on_owner(struct rw_semaphore *sem)
> >
> > rcu_read_lock();
> > owner = READ_ONCE(sem->owner);
> > - if (!rwsem_owner_is_writer(owner)) {
> > - /*
> > - * Don't spin if the rwsem is readers owned.
> > - */
> > - ret = !rwsem_owner_is_reader(owner);
> > + if (!owner || !is_rwsem_owner_spinnable(owner)) {
> > + ret = !owner; /* !owner is spinnable */
> > goto done;
> > }
>
> This is confusingly written. I think you mean ...
>
> if (!owner)
> goto done;
> if (!is_rwsem_owner_spinnable(owner)) {
> ret = false;
> goto done;
> }

Yes, that's cleaner. Waiman, mind sending a followup patch that cleans this up?

Thanks,

Ingo

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