[Qemu-devel] Re: [PATCHv2] qemu-kvm/vhost: fix up irqfd support

[Alex Williamson <alex.williamson@redhat.com>]

On Wed, 2010-10-06 at 19:02 +0200, Michael S. Tsirkin wrote:
> On Wed, Oct 06, 2010 at 10:48:44AM -0600, Alex Williamson wrote:
> > > -int msix_unset_mask_notifier(PCIDevice *dev, unsigned vector)
> > > +static int msix_unset_mask_notifier_for_vector(PCIDevice *dev, unsigned vector)
> > >  {
> > >      int r = 0;
> > > -    void *opaque;
> > >      if (vector >= dev->msix_entries_nr || !dev->msix_entry_used[vector])
> > >          return 0;
> > >  
> > > -    opaque = dev->msix_mask_notifier_opaque[vector];
> > > -
> > >      assert(dev->msix_mask_notifier);
> > > -    assert(opaque);
> > >  
> > >      /* Mask the old notifier unless it is already masked. */
> > >      if (!msix_is_masked(dev, vector)) {
> > > -        r = dev->msix_mask_notifier(dev, vector, opaque, true);
> > > +        r = dev->msix_mask_notifier(dev, vector, true);
> > >          if (r < 0) {
> > >              return r;
> > >          }
> > >      }
> > > -    dev->msix_mask_notifier_opaque[vector] = NULL;
> > > +    return r;
> > > +}
> > 
> > The above need to be combined to a single function now since the only
> > difference is s/true/false.
> > 
> > Alex
> 
> This is the way it was in the past, and it turned out to be very
> confusing to read since both variables: mask and assign are bool but
> polarity is reversed.
> 
> Unrolled it seems easier to grok.

You could always keep the functions as separate wrapper callers of the
common function so you only need to keep true = unset, false = set
straight in one place.  Thanks,

Alex