Re: [cocci] mm/slab: prepare for struct page conversion by spatch

[Vlastimil Babka <vbabka@suse.cz>]

On 11/7/21 13:50, Markus Elfring wrote:
>>> * Will any guidance help to find nicer solutions?
>>
>> Luis already proposed a perfectly reasonable solution.
> 
> His proposal can look a bit too terse (for affected implementation details),
> can't it?
> https://sympa.inria.fr/sympa/arc/cocci/2021-11/msg00017.html
> https://lore.kernel.org/cocci/YYVZva1hfwanXdyB@bombadil.infradead.org/

I don't mind terse, I wasn't asking for complete fixup of my patches,
but for hints, and I got plenty from all of you, thanks! Will try to
apply everything tomorrow.

> @@
> @@
> -struct page
> +struct slab

The above is itself incomplete to go from "struct page *page" to "struct
slab *slab", but will results in "struct slab *page".

So my attempts included:
- struct page *page
+ struct slab *slab

But that for some reason resulted in spatch reporting (IIRC) syntax
errors, so I had to change it to this:

- struct page *page;
+ struct slab *slab;

And that worked in most cases, but didn't handle the multiple variables
being declared nor declaration+assignment.

But I assume Luis' suggestion is supposed to work together with the rule
that does simply -page +slab. I'll see how it works out, and also
Julia's suggestion "just have one rule to change all occurences of page
to slab, and then have individual rules to change eg page_address(slab)
to slab_address(slab)."

Thanks,
Vlastimil