Re: [PATCH] rculist: list_first_or_null_rcu() should uselist_entry_rcu()

From: Tejun Heo
Date: Wed Jun 26 2013 - 11:26:15 EST


On Wed, Jun 26, 2013 at 07:17:52AM -0700, Paul E. McKenney wrote:
> > Do you mean something like the following?
> >
> > struct list_head *__next = ACCESS_ONCE(__ptr->next); \
> > likely(__ptr != __next) ? \
> > list_entry_rcu(__next, type, member) : NULL; \
> >
> > Yeah, that looks right to me.
>
> I would feel much better about this! Does it avoid warnings in your
> use cases?

Yeah, it does, and more importantly it adds the missing read barrier
during RCU deref. I'll give it another test and post the updated
version.

Thanks a lot!

--
tejun
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