On 26/01/08 11:31AM, Jonathan Cameron wrote: > On Wed, 7 Jan 2026 09:33:11 -0600 > John Groves <[email protected]> wrote: > > > The new fsdev driver provides pages/folios initialized compatibly with > > fsdax - normal rather than devdax-style refcounting, and starting out > > with order-0 folios. > > > > When fsdev binds to a daxdev, it is usually (always?) switching from the > > devdax mode (device.c), which pre-initializes compound folios according > > to its alignment. Fsdev uses fsdev_clear_folio_state() to switch the > > folios into a fsdax-compatible state. > > > > A side effect of this is that raw mmap doesn't (can't?) work on an fsdev > > dax instance. Accordingly, The fsdev driver does not provide raw mmap - > > devices must be put in 'devdax' mode (drivers/dax/device.c) to get raw > > mmap capability. > > > > In this commit is just the framework, which remaps pages/folios compatibly > > with fsdax. > > > > Enabling dax changes: > > > > * bus.h: add DAXDRV_FSDEV_TYPE driver type > > * bus.c: allow DAXDRV_FSDEV_TYPE drivers to bind to daxdevs > > * dax.h: prototype inode_dax(), which fsdev needs > > > > Suggested-by: Dan Williams <[email protected]> > > Suggested-by: Gregory Price <[email protected]> > > Signed-off-by: John Groves <[email protected]> > > > diff --git a/drivers/dax/Kconfig b/drivers/dax/Kconfig > > index d656e4c0eb84..491325d914a8 100644 > > --- a/drivers/dax/Kconfig > > +++ b/drivers/dax/Kconfig > > @@ -78,4 +78,21 @@ config DEV_DAX_KMEM > > > > Say N if unsure. > > > > +config DEV_DAX_FS > > + tristate "FSDEV DAX: fs-dax compatible device driver" > > + depends on DEV_DAX > > + default DEV_DAX > > What's the logic for the default? Generally I'd not expect a > default for something new like this (so default of default == no)
My thinking is that this is harmless unless you use it, but if you need it you need it. So defaulting to include the module seems viable. [ ... ] John
