Re: [PATCH v2 07/15] mm, swap: tidy up swap device and cluster info helpers

[David Hildenbrand]

On 05.09.25 21:13, Kairui Song wrote:
> From: Kairui Song <kasong@xxxxxxxxxxx>
>
> swp_swap_info is the most commonly used helper for retrieving swap info.
> It has an internal check that may lead to a NULL return value, but
> almost none of its caller checks the return value, making the internal
> check pointless. In fact, most of these callers already ensured the
> entry is valid and never expect a NULL value.
>
> Tidy this up and shorten the name. If the caller can make sure the

"Tidy this up and improve the function names." ?

> swap entry/type is valid and the device is pinned, use the new introduced
> __swap_entry_to_info/__swap_type_to_info instead. They have more debug
> sanity checks and lower overhead as they are inlined.
>
> Callers that may expect a NULL value should use
> swap_entry_to_info/swap_type_to_info instead.
>
> No feature change. The rearranged codes should have had no effect, or
> they should have been hitting NULL de-ref bugs already. Only some new
> sanity checks are added so potential issues may show up in debug build.
>
> The new helpers will be frequently used with swap table later when working
> with swap cache folios. A locked swap cache folio ensures the entries are
> valid and stable so these helpers are very helpful.
>
> Signed-off-by: Kairui Song <kasong@xxxxxxxxxxx>
> Acked-by: Chris Li <chrisl@xxxxxxxxxx>
> Reviewed-by: Barry Song <baohua@xxxxxxxxxx>
> ---

Acked-by: David Hildenbrand <david@xxxxxxxxxx>

--
Cheers

David / dhildenb