region.c
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/*
* Copyright(c) 2013-2015 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/cpumask.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/nd.h>
#include "nd.h"
static int nd_region_probe(struct device *dev)
{
int err, rc;
static unsigned long once;
struct nd_region_namespaces *num_ns;
struct nd_region *nd_region = to_nd_region(dev);
if (nd_region->num_lanes > num_online_cpus()
&& nd_region->num_lanes < num_possible_cpus()
&& !test_and_set_bit(0, &once)) {
dev_info(dev, "online cpus (%d) < concurrent i/o lanes (%d) < possible cpus (%d)\n",
num_online_cpus(), nd_region->num_lanes,
num_possible_cpus());
dev_info(dev, "setting nr_cpus=%d may yield better libnvdimm device performance\n",
nd_region->num_lanes);
}
rc = nd_blk_region_init(nd_region);
if (rc)
return rc;
rc = nd_region_register_namespaces(nd_region, &err);
num_ns = devm_kzalloc(dev, sizeof(*num_ns), GFP_KERNEL);
if (!num_ns)
return -ENOMEM;
if (rc < 0)
return rc;
num_ns->active = rc;
num_ns->count = rc + err;
dev_set_drvdata(dev, num_ns);
if (rc && err && rc == err)
return -ENODEV;
nd_region->btt_seed = nd_btt_create(nd_region);
nd_region->pfn_seed = nd_pfn_create(nd_region);
if (err == 0)
return 0;
/*
* Given multiple namespaces per region, we do not want to
* disable all the successfully registered peer namespaces upon
* a single registration failure. If userspace is missing a
* namespace that it expects it can disable/re-enable the region
* to retry discovery after correcting the failure.
* <regionX>/namespaces returns the current
* "<async-registered>/<total>" namespace count.
*/
dev_err(dev, "failed to register %d namespace%s, continuing...\n",
err, err == 1 ? "" : "s");
return 0;
}
static int child_unregister(struct device *dev, void *data)
{
nd_device_unregister(dev, ND_SYNC);
return 0;
}
static int nd_region_remove(struct device *dev)
{
struct nd_region *nd_region = to_nd_region(dev);
/* flush attribute readers and disable */
nvdimm_bus_lock(dev);
nd_region->ns_seed = NULL;
nd_region->btt_seed = NULL;
nd_region->pfn_seed = NULL;
dev_set_drvdata(dev, NULL);
nvdimm_bus_unlock(dev);
device_for_each_child(dev, NULL, child_unregister);
return 0;
}
static struct nd_device_driver nd_region_driver = {
.probe = nd_region_probe,
.remove = nd_region_remove,
.drv = {
.name = "nd_region",
},
.type = ND_DRIVER_REGION_BLK | ND_DRIVER_REGION_PMEM,
};
int __init nd_region_init(void)
{
return nd_driver_register(&nd_region_driver);
}
void nd_region_exit(void)
{
driver_unregister(&nd_region_driver.drv);
}
MODULE_ALIAS_ND_DEVICE(ND_DEVICE_REGION_PMEM);
MODULE_ALIAS_ND_DEVICE(ND_DEVICE_REGION_BLK);