Re: [XEN PATCH 2/7] x86/mm: address MISRA C:2012 Rule 2.1

[Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>]

On 2023-12-12 10:53, Jan Beulich wrote:
> On 12.12.2023 10:12, Nicola Vetrini wrote:
> > On 2023-12-12 02:42, Stefano Stabellini wrote:
> > > On Mon, 11 Dec 2023, Nicola Vetrini wrote:
> > > > The "return 0" after the swich statement in 'xen/arch/x86/mm.c'
> > > > is unreachable because all switch clauses end with returns.
> > > > However, some of them can be substituted with "break"s to allow
> > > > the "return 0" outside the switch to be reachable.
> > > >
> > > > No functional changes.
> > > This is correct but makes the code inconsistent. I would either 
> > > remove
> > > the return 0; at the end of arch_memory_op, or do the following:
> > >
> > > - initialize rc to 0 at the beginning: int rc = 0;
> > > - all switch clauses break instead of return;
> > > - at the end: return rc;
> > Given the feedback on the Arm side, the first solution is likely to be
> > preferred.
> I wouldn't mind either option, with
> - the former ensured to be okay with all compiler versions we (still)
>   support,
I tested a stripped-down version of the switch on godbolt.org (as far 
back as gcc-4.8.5) and it doesn't complain. It should be tested on a 
real Xen build, though.
> - the latter having the initialize rc to 0 part dropped; imo it's 
> better
>   if every case block makes sure to set the intended value explicitly.
This is a lot of churn, I'd rather avoid it.

--
Nicola Vetrini, BSc
Software Engineer, BUGSENG srl (https://bugseng.com)