On Wed, Feb 12, 2020 at 09:31:32AM +0100, Paolo Bonzini wrote:
> On 29/01/20 18:20, Stefan Hajnoczi wrote:
> > +	/* Semaphore semantics don't make sense when autoreset is enabled */
> > +	if ((flags & EFD_SEMAPHORE) && (flags & EFD_AUTORESET))
> > +		return -EINVAL;
> > +
> 
> I think they do, you just want to subtract 1 instead of setting the
> count to 0.  This way, writing 1 would be the post operation on the
> semaphore, while poll() would be the wait operation.

True!  Then EFD_AUTORESET is not a fitting name.  EFD_AUTOREAD or
EFD_POLL_READS?

Stefan