Re: [PATCH v3 0/7] Prepare mutable list iterators to cache cursor state

[Jani Nikula <jani.nikula@linux.intel.com>]

On Mon, 22 Jun 2026, Kaitao Cheng <kaitao.cheng@linux.dev> wrote:
> Add *_mutable() iterator variants for list, hlist and llist.  The new
> helpers are variadic and support both forms.  In the common case, the
> caller omits the temporary cursor and the macro creates a unique internal
> cursor with typeof(pos) and __UNIQUE_ID().  If a loop really needs an
> explicit temporary cursor, the caller can still pass it and the helper
> keeps the existing *_safe() behaviour.
>
> For example, a call site may use the shorter form:
>
>   list_for_each_entry_mutable(pos, head, member)
>
> or keep the explicit temporary cursor form:
>
>   list_for_each_entry_mutable(pos, tmp, head, member)

I'm unconvinced it's a good idea to allow two forms with macro trickery,
*especially* when it's not the last argument you can omit. I think it's
a footgun.

IMO stick with the first form only, and there'll always be the _safe
variant that can be used when the temp pointer is needed.


BR,
Jani.


-- 
Jani Nikula, Intel