Re: [PATCH v3 08/13] xen/pvcalls: implement accept command

[Stefano Stabellini]

On Mon, 14 Aug 2017, Boris Ostrovsky wrote:
> > > +
> > > +    ret = bedata->rsp[req_id].ret;
> > 
> > You can just return bedata->rsp[req_id].ret;
> 
> Or maybe not. The slot may get reused by the time you get to the end.

Right!

> > 
> > -boris
> > 
> > > +    /* read ret, then set this rsp slot to be reused */
> > > +    smp_mb();
> > > +    WRITE_ONCE(bedata->rsp[req_id].req_id, PVCALLS_INVALID_ID);
> > > +    WRITE_ONCE(map->passive.inflight_req_id, PVCALLS_INVALID_ID);
> > > +    return ret;
> > > +}
>