Re: [XEN PATCH 01/10] xen/include: address violations of MISRA C Rule 20.7

[Jan Beulich <jbeulich@xxxxxxxx>]

On 29.02.2024 16:27, Nicola Vetrini wrote:
> --- a/xen/include/xen/kconfig.h
> +++ b/xen/include/xen/kconfig.h
> @@ -25,7 +25,7 @@
>  #define __ARG_PLACEHOLDER_1 0,
>  #define config_enabled(cfg) _config_enabled(cfg)
>  #define _config_enabled(value) __config_enabled(__ARG_PLACEHOLDER_##value)
> -#define __config_enabled(arg1_or_junk) ___config_enabled(arg1_or_junk 1, 0)
> +#define __config_enabled(arg1_or_junk) ___config_enabled(arg1_or_junk (1), 
> (0))
>  #define ___config_enabled(__ignored, val, ...) val

In addition to what Andrew said, would you mind clarifying what exactly the
violation is here? I find it questionable that numeric literals need
parenthesizing; they don't normally need to, aynwhere.

> --- a/xen/include/xen/list.h
> +++ b/xen/include/xen/list.h
> @@ -490,9 +490,9 @@ static inline void list_splice_init(struct list_head 
> *list,
>   * @member: the name of the list_struct within the struct.
>   */
>  #define list_for_each_entry(pos, head, member)                          \
> -    for (pos = list_entry((head)->next, typeof(*pos), member);          \
> -         &pos->member != (head);                                        \
> -         pos = list_entry(pos->member.next, typeof(*pos), member))
> +    for (pos = list_entry((head)->next, typeof(*(pos)), member);          \
> +         &(pos)->member != (head);                                      \
> +         pos = list_entry((pos)->member.next, typeof(*(pos)), member))

this ends up inconsistent, which I think isn't nice: Some uses of "pos"
are now parenthesized, while others aren't. Applies further down as well.

You may also want to take this as a strong suggestion to split dissimilar
changes, so uncontroversial parts can go in.

> @@ -977,4 +977,3 @@ static inline void hlist_add_after_rcu(struct hlist_node 
> *prev,
>            pos = pos->next)
>  
>  #endif /* __XEN_LIST_H__ */
> -

Unrelated change?

> --- a/xen/include/xen/spinlock.h
> +++ b/xen/include/xen/spinlock.h
> @@ -94,7 +94,7 @@ struct lock_profile_qhead {
>      int32_t                   idx;     /* index for printout */
>  };
>  
> -#define _LOCK_PROFILE(lockname) { .name = #lockname, .lock = &lockname, }
> +#define _LOCK_PROFILE(lockname) { .name = #lockname, .lock = &(lockname), }

This also may be viewed as falling in the same category, but is less
problematic because the other use is stringification, when in principle
some kind of expression would be passed in (albeit in practice I don't
expect anyone would do that).

Jan