Re: [PATCH v7] mm: assert exclusive nid/zonenum bits at the page/folio access sites

[David Hildenbrand (Arm)]

>>  
>>  static inline enum zone_type folio_zonenum(const struct folio *folio)
>>  {
>> +#if ZONES_WIDTH != 0
>> +	ASSERT_EXCLUSIVE_BITS(folio->flags, ZONES_MASK << ZONES_PGSHIFT);
>> +#endif
>>  	return memdesc_zonenum(folio->flags);
>>  }
>>  
> 
> Better to factor out a common macro alongside a comment for these two '#if'?

Yes.

And while looking at it, doesn't memdesc_section have similar problems? And
there are other callers of memdesc_zonenum we wouldn't handle. So the
macro approach is only partially helpful I thing.

Maybe we should just pass by reference and fixup all callers? Ends up the cleanest.

Untested: