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RE: [PATCH v2] xen/arm: p2m: Populate pages for GICv2 mapping in arch_domain_create()
- To: Jan Beulich <jbeulich@xxxxxxxx>
- From: Henry Wang <Henry.Wang@xxxxxxx>
- Date: Fri, 14 Oct 2022 12:10:38 +0000
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- Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>, Bertrand Marquis <Bertrand.Marquis@xxxxxxx>, Wei Chen <Wei.Chen@xxxxxxx>, Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxxx>, Julien Grall <julien@xxxxxxx>
- Delivery-date: Fri, 14 Oct 2022 12:11:17 +0000
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- Thread-topic: [PATCH v2] xen/arm: p2m: Populate pages for GICv2 mapping in arch_domain_create()
Hi Jan,
> -----Original Message-----
> From: Jan Beulich <jbeulich@xxxxxxxx>
> Subject: Re: [PATCH v2] xen/arm: p2m: Populate pages for GICv2 mapping in
> arch_domain_create()
>
> On 14.10.2022 13:04, Henry Wang wrote:
> >> -----Original Message-----
> >> From: Jan Beulich <jbeulich@xxxxxxxx>
> >>
> >>> My initial thought is the "else if" part in p2m_set_allocation. It might
> >>> be
> >>> wrong. Would the code below seems ok to you?
> >>>
> >>> int err;
> >>>
> >>> do {
> >>> err = p2m_teardown_allocation(d)
> >>> } while ( err == -ERESTART )
> >>
> >> Sure, one of several ways of doing it.
> >
> > Thanks for your confirmation. Just to play safe if you have more simple
> > Solutions please do raise it. It is a good opportunity for me to learn and
> > personally I am not a big fan of either do-while or the introduced "err"
> > which is used only by p2m_teardown_allocation(d), considering the
> > p2m_final_teardown(d) has a void return type...
>
> Personally I would probably have written
>
> while ( p2m_teardown_allocation(d) == -ERESTART )
> /* Nothing - no preemption support here. */;
Thanks very much for the suggestions! I didn't think of the /* */
part and I really like this idea. This said, a quick search of different
coding styles and I found [1] mentioned:
"Empty loop bodies should use either empty braces or continue. "
So I will probably follow...
>
> or
>
> while ( p2m_teardown_allocation(d) == -ERESTART )
> continue; /* No preemption support here. */
...this way. Great experience of learning, thanks!
[1] https://google.github.io/styleguide/cppguide.html
Kind regards,
Henry
>
> . Otoh with the "err" variable you could ASSERT(!err) after the loop.
>
> Jan
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