device-dax: Add /sys/class/dax backwards compatibility
On the expectation that some environments may not upgrade libdaxctl
(userspace component that depends on the /sys/class/dax hierarchy),
provide a default / legacy dax_pmem_compat driver. The dax_pmem_compat
driver implements the original /sys/class/dax sysfs layout rather than
/sys/bus/dax. When userspace is upgraded it can blacklist this module
and switch to the dax_pmem driver going forward.
CONFIG_DEV_DAX_PMEM_COMPAT and supporting code will be deleted according
to the dax_pmem entry in Documentation/ABI/obsolete/.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/dax/bus.h b/drivers/dax/bus.h
index 395ab812..ce97755 100644
--- a/drivers/dax/bus.h
+++ b/drivers/dax/bus.h
@@ -2,7 +2,8 @@
/* Copyright(c) 2016 - 2018 Intel Corporation. All rights reserved. */
#ifndef __DAX_BUS_H__
#define __DAX_BUS_H__
-struct device;
+#include <linux/device.h>
+
struct dev_dax;
struct resource;
struct dax_device;
@@ -10,8 +11,23 @@ struct dax_region;
void dax_region_put(struct dax_region *dax_region);
struct dax_region *alloc_dax_region(struct device *parent, int region_id,
struct resource *res, unsigned int align, unsigned long flags);
-struct dev_dax *devm_create_dev_dax(struct dax_region *dax_region, int id,
- struct dev_pagemap *pgmap);
+
+enum dev_dax_subsys {
+ DEV_DAX_BUS,
+ DEV_DAX_CLASS,
+};
+
+struct dev_dax *__devm_create_dev_dax(struct dax_region *dax_region, int id,
+ struct dev_pagemap *pgmap, enum dev_dax_subsys subsys);
+
+static inline struct dev_dax *devm_create_dev_dax(struct dax_region *dax_region,
+ int id, struct dev_pagemap *pgmap)
+{
+ return __devm_create_dev_dax(dax_region, id, pgmap, DEV_DAX_BUS);
+}
+
+/* to be deleted when DEV_DAX_CLASS is removed */
+struct dev_dax *__dax_pmem_probe(struct device *dev, enum dev_dax_subsys subsys);
struct dax_device_driver {
struct device_driver drv;
@@ -26,6 +42,10 @@ int __dax_driver_register(struct dax_device_driver *dax_drv,
void dax_driver_unregister(struct dax_device_driver *dax_drv);
void kill_dev_dax(struct dev_dax *dev_dax);
+#if IS_ENABLED(CONFIG_DEV_DAX_PMEM_COMPAT)
+int dev_dax_probe(struct device *dev);
+#endif
+
/*
* While run_dax() is potentially a generic operation that could be
* defined in include/linux/dax.h we don't want to grow any users
