linux/drivers/nvdimm/region.c
Dan Williams 87a30e1f05 driver-core, libnvdimm: Let device subsystems add local lockdep coverage
For good reason, the standard device_lock() is marked
lockdep_set_novalidate_class() because there is simply no sane way to
describe the myriad ways the device_lock() ordered with other locks.
However, that leaves subsystems that know their own local device_lock()
ordering rules to find lock ordering mistakes manually. Instead,
introduce an optional / additional lockdep-enabled lock that a subsystem
can acquire in all the same paths that the device_lock() is acquired.

A conversion of the NFIT driver and NVDIMM subsystem to a
lockdep-validate device_lock() scheme is included. The
debug_nvdimm_lock() implementation implements the correct lock-class and
stacking order for the libnvdimm device topology hierarchy.

Yes, this is a hack, but hopefully it is a useful hack for other
subsystems device_lock() debug sessions. Quoting Greg:

    "Yeah, it feels a bit hacky but it's really up to a subsystem to mess up
     using it as much as anything else, so user beware :)

     I don't object to it if it makes things easier for you to debug."

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/156341210661.292348.7014034644265455704.stgit@dwillia2-desk3.amr.corp.intel.com
2019-07-18 16:23:27 -07:00

161 lines
4.1 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright(c) 2013-2015 Intel Corporation. All rights reserved.
*/
#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_dbg(dev, "online cpus (%d) < concurrent i/o lanes (%d) < possible cpus (%d)\n",
num_online_cpus(), nd_region->num_lanes,
num_possible_cpus());
dev_dbg(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;
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);
}
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;
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 nd_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);