Re: [Qemu-devel] [PATCH 1/4] linux-aio: queue requests that cannot be submitted

[Paolo Bonzini <pbonzini@redhat.com>]

On 11/12/2014 13:49, Kevin Wolf wrote:
> > -    } else {
> > -        i = ret;
> > +        abort();
> >      }
> 
> abort() doesn't feel right here.

man doesn't suggest any error that can actually happen.

> > +    QSIMPLEQ_INSERT_TAIL(&s->io_q.pending, laiocb, next);
> > +    s->io_q.idx++;
> > +    if (s->io_q.idx == (s->io_q.plugged ? MAX_QUEUED_IO : 1)) {
> 
> More naturally written and more obviously correct as (!s->io_q,plugged ||
> s->io_q.idx >= MAX_QUEUED_IO). Which happens to be what the next patch
> converts it to, so I won't spend much time thinking about whether this
> version is actually right.

Sort of.  If the queue is blocked due to -EAGAIN, I don't want to
io_submit every time an operation is queued, hence the ==.  The next
patch adds !s->io_q.blocked, so it can use the more natural and indeed
more obvious expression.

Paolo