> + struct {
> + /*
> + * ZONE_DEVICE pages are never on an lru or handled by
> + * a slab allocator, this points to the hosting device
> + * page map.
> + */
> + struct dev_pagemap *pgmap;
> + /*
> + * inode association for MEMORY_DEVICE_FS_DAX page-idle
> + * callbacks. Note that we don't use ->mapping since
> + * that has hard coded page-cache assumptions in
> + * several paths.
> + */
What assumptions? I'd much rather fix those up than having two fields
that have the same functionality.
