Re: [PATCH] llist: Put parentheses around parameters of llist_for_each_entry_safe()

From: Huang\, Ying
Date: Tue Sep 26 2017 - 03:01:57 EST


Hi, Byungchul,

Byungchul Park <byungchul.park@xxxxxxx> writes:

> It would be somewhat safer to put parentheses around parameters of
> a macro with parameters. Put it.
>
> Signed-off-by: Byungchul Park <byungchul.park@xxxxxxx>
> ---
> include/linux/llist.h | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/include/linux/llist.h b/include/linux/llist.h
> index 1957635..e280b297 100644
> --- a/include/linux/llist.h
> +++ b/include/linux/llist.h
> @@ -183,10 +183,10 @@ static inline void init_llist_head(struct llist_head *list)
> * reverse the order by yourself before traversing.
> */
> #define llist_for_each_entry_safe(pos, n, node, member) \
> - for (pos = llist_entry((node), typeof(*pos), member); \
> + for ((pos) = llist_entry((node), typeof(*(pos)), member); \
> member_address_is_nonnull(pos, member) && \
> - (n = llist_entry(pos->member.next, typeof(*n), member), true); \
> - pos = n)
> + ((n) = llist_entry((pos)->member.next, typeof(*(n)), member), true); \
> + (pos) = (n))
>
> /**
> * llist_empty - tests whether a lock-less list is empty

The original code follows the style of list_for_each_entry_safe(). The
parameters "pos" and "n" must be variable. Because list_xxx family
functions work well so far, I think we needn't to change it too.

Best Regards,
Huang, Ying