linux-stable/drivers/nvdimm/region.c
Dan Williams 6aa734a2f3 libnvdimm, region, pmem: fix 'badblocks' sysfs_get_dirent() reference lifetime
We need to hold a reference on the 'dirent' until we are sure there are
no more notifications that will be sent. As noted in the new comments we
take advantage of the fact that the references are taken and dropped
under device_lock() and that nd_device_notify() holds device_lock() over
new badblocks notifications. The notifications that happen when
badblocks are cleared only occur while the device is active.

Also take the opportunity to fix up the error messages to report the
user visible effect of a sysfs_get_dirent() failure.

Fixes: 975750a98c ("libnvdimm, pmem: Add sysfs notifications to badblocks")
Cc: Toshi Kani <toshi.kani@hpe.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-06-30 18:56:03 -07:00

168 lines
4.5 KiB
C

/*
* 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-core.h"
#include "nd.h"
static int nd_region_probe(struct device *dev)
{
int err, rc;
static unsigned long once;
struct nd_region_data *ndrd;
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_region_activate(nd_region);
if (rc)
return rc;
rc = nd_blk_region_init(nd_region);
if (rc)
return rc;
rc = nd_region_register_namespaces(nd_region, &err);
if (rc < 0)
return rc;
ndrd = dev_get_drvdata(dev);
ndrd->ns_active = rc;
ndrd->ns_count = rc + err;
if (rc && err && rc == err)
return -ENODEV;
if (is_nd_pmem(&nd_region->dev)) {
struct resource ndr_res;
if (devm_init_badblocks(dev, &nd_region->bb))
return -ENODEV;
nd_region->bb_state = sysfs_get_dirent(nd_region->dev.kobj.sd,
"badblocks");
if (!nd_region->bb_state)
dev_warn(&nd_region->dev,
"'badblocks' notification disabled\n");
ndr_res.start = nd_region->ndr_start;
ndr_res.end = nd_region->ndr_start + nd_region->ndr_size - 1;
nvdimm_badblocks_populate(nd_region, &nd_region->bb, &ndr_res);
}
nd_region->btt_seed = nd_btt_create(nd_region);
nd_region->pfn_seed = nd_pfn_create(nd_region);
nd_region->dax_seed = nd_dax_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);
device_for_each_child(dev, NULL, child_unregister);
/* flush attribute readers and disable */
nvdimm_bus_lock(dev);
nd_region->ns_seed = NULL;
nd_region->btt_seed = NULL;
nd_region->pfn_seed = NULL;
nd_region->dax_seed = NULL;
dev_set_drvdata(dev, NULL);
nvdimm_bus_unlock(dev);
/*
* Note, this assumes device_lock() context to not race
* nd_region_notify()
*/
sysfs_put(nd_region->bb_state);
nd_region->bb_state = NULL;
return 0;
}
static int child_notify(struct device *dev, void *data)
{
nd_device_notify(dev, *(enum nvdimm_event *) data);
return 0;
}
static void nd_region_notify(struct device *dev, enum nvdimm_event event)
{
if (event == NVDIMM_REVALIDATE_POISON) {
struct nd_region *nd_region = to_nd_region(dev);
struct resource res;
if (is_nd_pmem(&nd_region->dev)) {
res.start = nd_region->ndr_start;
res.end = nd_region->ndr_start +
nd_region->ndr_size - 1;
nvdimm_badblocks_populate(nd_region,
&nd_region->bb, &res);
if (nd_region->bb_state)
sysfs_notify_dirent(nd_region->bb_state);
}
}
device_for_each_child(dev, &event, child_notify);
}
static struct nd_device_driver nd_region_driver = {
.probe = nd_region_probe,
.remove = nd_region_remove,
.notify = nd_region_notify,
.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);