On Thu, 2010-08-19 at 17:10 +0100, Jeremy Fitzhardinge wrote:
> On 08/19/2010 03:54 AM, Stefano Stabellini wrote:
> > On Thu, 19 Aug 2010, Ian Campbell wrote:
> >> On Thu, 2010-08-19 at 11:50 +0100, Ian Campbell wrote:
> >>> On Thu, 2010-08-19 at 11:37 +0100, Stefano Stabellini wrote:
> >>>> On Thu, 19 Aug 2010, Ian Campbell wrote:
> >>>>> if (r && !(r == XEN_PLATFORM_ERR_MAGIC &&
> >>>>> + (xen_emul_unplug != -1) &&
> >>>>> (xen_emul_unplug & XEN_UNPLUG_IGNORE)))
> >>>> I wouldn't add xen_emul_unplug != -1 because it should be clear that
> >>>> xen_emul_unplug & XEN_UNPLUG_IGNORE always implies xen_emul_unplug != -1.
> >>> That's not correct since -1 is all 1s. So you can get a false positive
> >>> for "xen_emul_unplug & XEN_UNPLUG_IGNORE" if xen_emul_unplug == -1.
> >> IOW if we were to rewrite the test to use less boolean logic the patch
> >> might look like:
> >>
> >> if (r) {
> >> if (r != XEN_PLATFORM_ERR_MAGIC)
> >> return;
> >> + if (xen_emul_unplug == -1)
> >> + return;
> >> if (!(xen_emul_unplug & XEN_UNPLUG_IGNORE))
> >> return;
> >> }
> >>
> >> Perhaps this refactoring is worthwhile in any case? It certainly makes
> >> my head hurt less ;-)
> >>
> >
> > Yeah, it is probably worth it anyway :)
>
> Treating a variable as an integer and a bitfield seems like a bad idea.
Should be fine? I'd just #define XEN_UNPLUG_ALL_THE_BITS ~0U for the
sake of cosmetics...
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