Re: [XEN PATCH v2 3/7] xen/list: address violations of MISRA C Rule 20.7

[Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>]

On 2024-03-11 08:48, Jan Beulich wrote:
> On 08.03.2024 12:21, Nicola Vetrini wrote:
> > --- a/xen/include/xen/list.h
> > +++ b/xen/include/xen/list.h
> > @@ -479,9 +479,9 @@ static inline void list_splice_init(struct 
> > list_head *list,
> >   * @n:      another &struct list_head to use as temporary storage
> >   * @head:   the head for your list.
> >   */
> > -#define list_for_each_backwards_safe(pos, n, head)              \
> > -    for ( pos = (head)->prev, n = pos->prev; pos != (head);     \
> > -          pos = n, n = pos->prev )
> > +#define list_for_each_backwards_safe(pos, n, head)                 \
> > +    for ( (pos) = (head)->prev, n = (pos)->prev; (pos) != (head);  \
> > +          (pos) = n, n = (pos)->prev )
> I think this is worse than before and incomplete: At least the rhs use 
> of n
> also needs parenthesizing. Plus if pos is parenthesized even in lhs
> instances, imo n ought to be, too.
You are right: this was simply an oversight.

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