On Thu, Jun 27, 2024 at 10:54:19AM +1000, Alistair Popple wrote: > When a fs dax page is freed it has to notify filesystems that the page > has been unpinned/unmapped and is free. Currently this involves > special code in the page free paths to detect a transition of refcount > from 2 to 1 and to call some fs dax specific code. > > A future change will require this to happen when the page refcount > drops to zero. In this case we can use the existing > pgmap->ops->page_free() callback so wire that up for all devices that > support FS DAX (nvdimm and virtio). Given that ->page_ffree is only called from free_zone_device_folio and right next to a switch on the the type, can't we just do the wake_up_var there without the somewhat confusing indirect call that just back in common code without any driver logic?
