Re: [RFC] eventfd: add EFD_AUTORESET flag

[Paolo Bonzini]

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.

Paolo