Subject: Re: [PATCH 1/3] rcu: Introduce hlist_nulls variant of hlist

From: "Paul E. McKenney" <[email-masked]>
Date: Wed, 19 Nov 2008 13:17:39 -0800

On Wed, Nov 19, 2008 at 04:53:47PM -0200, Arnaldo Carvalho de Melo wrote:
> Em Wed, Nov 19, 2008 at 10:46:24AM -0800, Paul E. McKenney escreveu:
> > For whatever it is worth, here is a more complete use case, on the
> > off-chance that it becomes useful some time:
> > 
> > 	retry:
> > 	rcu_read_lock();
> 
> 	retry: /* should be here, huh? */

Indeed!  Either that or have an rcu_read_unlock() before the
goto retry.

Good catch!

							Thanx, Paul

> > 	hlist_nulls_for_each_entry_rcu(tpos, pos, head, hn_node) {
> > 		if (!(curgen = still_valid(tpos)))
> > 			goto retry;
> > 		if (needs_deletion(tpos)) {
> > 			spin_lock(&update_side_lock);
> > 			if (still_valid(tpos) == curgen)
> > 				hlist_nulls_del_init_rcu(pos);
> > 			spin_unlock(&update_side_lock);
> > 		}
> > 	}
> > 	rcu_read_unlock();
> 
> - Arnaldo