Re: [PATCH -v2 14/33] locking,m68k: Implement atomic_fetch_{add,sub,and,or,xor}()

From: Peter Zijlstra
Date: Thu Jun 16 2016 - 08:50:25 EST


On Thu, Jun 16, 2016 at 02:43:29PM +0200, Andreas Schwab wrote:
> Peter Zijlstra <peterz@xxxxxxxxxxxxx> writes:
> >> > +/*
> >> > + * Am I reading these CAS loops right in that %2 is the old value and the first
> >> > + * iteration uses an uninitialized value?
> >> > + *
> >> > + * Would it not make sense to add: tmp = atomic_read(v); to avoid this?
> >> > + */

> No, there is nothing to fix here.

OK, care to elucidate? Clearly I need help reading this.

I'm more than happy to remove the comment, but I would like to better
understand.