On Thu, 29 Jan 2026 16:04:37 -0500
Gregory Price [off-list ref] wrote:

CXL regions may wish not to auto-configure their memory as dax kmem,
but the current plumbing defaults all cxl-created dax devices to the
kmem driver.  This exposes them to hotplug policy, even if the user
intends to use the memory as a dax device.

Add plumbing to allow CXL drivers to select whether a DAX region should
default to kmem (DAXDRV_KMEM_TYPE) or device (DAXDRV_DEVICE_TYPE).

Add a 'dax_driver' field to struct cxl_dax_region and update
devm_cxl_add_dax_region() to take a dax_driver_type parameter.

In drivers/dax/cxl.c, the IORESOURCE_DAX_KMEM flag used by dax driver
matching code is now set conditionally based on dax_region->dax_driver.

Exports `enum dax_driver_type` to linux/dax.h for use in the cxl driver.

All current callers pass DAXDRV_KMEM_TYPE for backward compatibility.

Cc: John Groves <redacted>
Signed-off-by: Gregory Price <gourry@gourry.net>

LGTM
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>