Re: [PATCH tip/core/rcu 01/14] rcu: Protect rcu_boost() lockless accesses with ACCESS_ONCE()

From: Davidlohr Bueso
Date: Fri Jan 09 2015 - 01:42:24 EST


On Thu, 2015-01-08 at 07:22 -0800, Paul E. McKenney wrote:
> > Didn't we just obsolete ACCESS_ONCE with that {READ,WRITE}_ONCE stuff?
>
> Indeed we did! But that was after I did this commit back on October 29th.
>
> I am planning a bulk change to READ_ONCE() and ASSIGN_ONCE() either as
> the last patch for 3.20 or as the first one for 3.21. Probably as the
> first for 3.21 to minimize rebasing hassles with any needed 3.20 fixes.

That reminds me, I think the new conversion for stores will most likely
introduce silly arg bugs:

- ACCESS_ONCE(a) = b;
+ ASSIGN_ONCE(b, a);

Thanks,
Davidlohr

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