On Tue, Sep 10, 2024 at 02:14:29PM +1000, Alistair Popple wrote: > @@ -337,6 +341,7 @@ struct folio { > /* private: */ > }; > /* public: */ > + struct dev_pagemap *pgmap; Shouldn't that be indented by one more tab stop? And for ease of reading, perhaps it should be placed either immediately before or after 'struct list_head lru;'? > +++ b/include/linux/mmzone.h > @@ -1134,6 +1134,12 @@ static inline bool is_zone_device_page(const struct page *page) > return page_zonenum(page) == ZONE_DEVICE; > } > > +static inline struct dev_pagemap *page_dev_pagemap(const struct page *page) > +{ > + WARN_ON(!is_zone_device_page(page)); > + return page_folio(page)->pgmap; > +} I haven't read to the end yet, but presumably we'll eventually want: static inline struct dev_pagemap *folio_dev_pagemap(const struct folio *folio) { WARN_ON(!folio_is_zone_device(folio)) return folio->pgmap; } and since we'll want it eventually, maybe now is the time to add it, and make page_dev_pagemap() simply call it?