Re: [PATCH] xen/irq: Delete the pirq_cleanup_check() macro

[Jan Beulich <jbeulich@xxxxxxxx>]

On 30.07.2025 00:31, Andrew Cooper wrote:
> MISRA Rule 5.5 objects to a macro aliasing a function, which is what
> pirq_cleanup_check() does.  The macro is an overly-complicated way of writing:
> 
>     if ( !pirq->evtchn )
>         pirq_cleanup_check(pirq, d);

The way you word this does not in any way appreciate the original intention
behind introducing this macro: It wasn't to write something in an overly
complicated form, but to make sure no call site would mistakenly omit the
condition. IOW ...

> There are only a handful of users, so expand it inline to be plain regular C.
> 
> Doing this shows one path now needing braces, and one path in
> evtchn_bind_pirq() where the expanded form simplies back to no delta, as it
> follows an unconditional clear of info->evtchn.

... this one place you don't need to touch is now becoming at least close
to a bad precedent.

The code changes themselves being all fine, the above is not an objection
to the patch. I'd much appreciate if the description was re-worded, though,
to take into account the original intention. And obviously with the original
intention in mind, whether pleasing Misra this way is actually outweighing
the (latent) risk wants (re)considering.

Jan