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>

1 files changed, 0 insertions, 90 deletions

diff --git a/drivers/dax/pmem.c b/drivers/dax/pmem.c
deleted file mode 100644
index d3cefa7868ac..000000000000
--- a/drivers/dax/pmem.c
+++ /dev/null
@@ -1,90 +0,0 @@
-/*
- * Copyright(c) 2016 Intel Corporation. All rights reserved.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of version 2 of the GNU General Public License as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License for more details.
- */
-#include <linux/percpu-refcount.h>
-#include <linux/memremap.h>
-#include <linux/module.h>
-#include <linux/pfn_t.h>
-#include "../nvdimm/pfn.h"
-#include "../nvdimm/nd.h"
-#include "bus.h"
-
-static int dax_pmem_probe(struct device *dev)
-{
-	struct resource res;
-	int rc, id, region_id;
-	resource_size_t offset;
-	struct nd_pfn_sb *pfn_sb;
-	struct dev_dax *dev_dax;
-	struct nd_namespace_io *nsio;
-	struct dax_region *dax_region;
-	struct dev_pagemap pgmap = { 0 };
-	struct nd_namespace_common *ndns;
-	struct nd_dax *nd_dax = to_nd_dax(dev);
-	struct nd_pfn *nd_pfn = &nd_dax->nd_pfn;
-
-	ndns = nvdimm_namespace_common_probe(dev);
-	if (IS_ERR(ndns))
-		return PTR_ERR(ndns);
-	nsio = to_nd_namespace_io(&ndns->dev);
-
-	/* parse the 'pfn' info block via ->rw_bytes */
-	rc = devm_nsio_enable(dev, nsio);
-	if (rc)
-		return rc;
-	rc = nvdimm_setup_pfn(nd_pfn, &pgmap);
-	if (rc)
-		return rc;
-	devm_nsio_disable(dev, nsio);
-
-	/* reserve the metadata area, device-dax will reserve the data */
-        pfn_sb = nd_pfn->pfn_sb;
-	offset = le64_to_cpu(pfn_sb->dataoff);
-	if (!devm_request_mem_region(dev, nsio->res.start, offset,
-				dev_name(&ndns->dev))) {
-                dev_warn(dev, "could not reserve metadata\n");
-                return -EBUSY;
-        }
-
-	rc = sscanf(dev_name(&ndns->dev), "namespace%d.%d", &region_id, &id);
-	if (rc != 2)
-		return -EINVAL;
-
-	/* adjust the dax_region resource to the start of data */
-	memcpy(&res, &pgmap.res, sizeof(res));
-	res.start += offset;
-	dax_region = alloc_dax_region(dev, region_id, &res,
-			le32_to_cpu(pfn_sb->align), PFN_DEV|PFN_MAP);
-	if (!dax_region)
-		return -ENOMEM;
-
-	dev_dax = devm_create_dev_dax(dax_region, id, &pgmap);
-
-	/* child dev_dax instances now own the lifetime of the dax_region */
-	dax_region_put(dax_region);
-
-	return PTR_ERR_OR_ZERO(dev_dax);
-}
-
-static struct nd_device_driver dax_pmem_driver = {
-	.probe = dax_pmem_probe,
-	.drv = {
-		.name = "dax_pmem",
-	},
-	.type = ND_DRIVER_DAX_PMEM,
-};
-
-module_nd_driver(dax_pmem_driver);
-
-MODULE_LICENSE("GPL v2");
-MODULE_AUTHOR("Intel Corporation");
-MODULE_ALIAS_ND_DEVICE(ND_DEVICE_DAX_PMEM);