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Date: Fri, 28 Feb 2025 08:36:34 -0700
From: Keith Busch <kbusch@kernel.org>
To: Sean Christopherson <seanjc@google.com>
Cc: Lei Yang <leiyang@redhat.com>, Keith Busch <kbusch@meta.com>,
	pbonzini@redhat.com, kvm@vger.kernel.org,
	virtualization@lists.linux.dev, x86@kernel.org,
	netdev@vger.kernel.org
Subject: Re: [PATCHv3 0/2]
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In-Reply-To: <Z8HWab5J5O29xsJj@google.com>

On Fri, Feb 28, 2025 at 07:29:45AM -0800, Sean Christopherson wrote:
> On Fri, Feb 28, 2025, Keith Busch wrote:
> > On Fri, Feb 28, 2025 at 06:32:47AM -0800, Sean Christopherson wrote:
> > > > @@ -35,10 +35,12 @@ static inline int call_once(struct once *once, int (*cb)(struct once *))
> > > >                 return 0;
> > > >  
> > > >          guard(mutex)(&once->lock);
> > > > -        WARN_ON(atomic_read(&once->state) == ONCE_RUNNING);
> > > > -        if (atomic_read(&once->state) != ONCE_NOT_STARTED)
> > > > +        if (WARN_ON(atomic_read(&once->state) == ONCE_RUNNING))
> > > >                  return -EINVAL;
> > > >  
> > > > +        if (atomic_read(&once->state) == ONCE_COMPLETED)
> > > > +                return 0;
> > > > +
> > > >          atomic_set(&once->state, ONCE_RUNNING);
> > > >         r = cb(once);
> > > >         if (r)
> > 
> > Possible suggestion since it seems odd to do an atomic_read twice on the
> > same value.
> 
> Yeah, good call.  At the risk of getting too cute, how about this?

Sure, that also looks good to me.