linux-stable/drivers/dax/pmem/compat.c
Dan Williams 730926c3b0 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>
2019-01-06 21:41:57 -08:00

73 lines
1.7 KiB
C

// SPDX-License-Identifier: GPL-2.0
/* Copyright(c) 2016 - 2018 Intel Corporation. All rights reserved. */
#include <linux/percpu-refcount.h>
#include <linux/memremap.h>
#include <linux/module.h>
#include <linux/pfn_t.h>
#include <linux/nd.h>
#include "../bus.h"
/* we need the private definitions to implement compat suport */
#include "../dax-private.h"
static int dax_pmem_compat_probe(struct device *dev)
{
struct dev_dax *dev_dax = __dax_pmem_probe(dev, DEV_DAX_CLASS);
int rc;
if (IS_ERR(dev_dax))
return PTR_ERR(dev_dax);
if (!devres_open_group(&dev_dax->dev, dev_dax, GFP_KERNEL))
return -ENOMEM;
device_lock(&dev_dax->dev);
rc = dev_dax_probe(&dev_dax->dev);
device_unlock(&dev_dax->dev);
devres_close_group(&dev_dax->dev, dev_dax);
if (rc)
devres_release_group(&dev_dax->dev, dev_dax);
return rc;
}
static int dax_pmem_compat_release(struct device *dev, void *data)
{
device_lock(dev);
devres_release_group(dev, to_dev_dax(dev));
device_unlock(dev);
return 0;
}
static int dax_pmem_compat_remove(struct device *dev)
{
device_for_each_child(dev, NULL, dax_pmem_compat_release);
return 0;
}
static struct nd_device_driver dax_pmem_compat_driver = {
.probe = dax_pmem_compat_probe,
.remove = dax_pmem_compat_remove,
.drv = {
.name = "dax_pmem_compat",
},
.type = ND_DRIVER_DAX_PMEM,
};
static int __init dax_pmem_compat_init(void)
{
return nd_driver_register(&dax_pmem_compat_driver);
}
module_init(dax_pmem_compat_init);
static void __exit dax_pmem_compat_exit(void)
{
driver_unregister(&dax_pmem_compat_driver.drv);
}
module_exit(dax_pmem_compat_exit);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Intel Corporation");
MODULE_ALIAS_ND_DEVICE(ND_DEVICE_DAX_PMEM);