![Dan Williams](/assets/img/avatar_default.png)
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
161 lines
4.1 KiB
C
161 lines
4.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright(c) 2013-2015 Intel Corporation. All rights reserved.
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*/
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#include <linux/cpumask.h>
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#include <linux/module.h>
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#include <linux/device.h>
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#include <linux/nd.h>
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#include "nd-core.h"
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#include "nd.h"
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static int nd_region_probe(struct device *dev)
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{
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int err, rc;
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static unsigned long once;
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struct nd_region_data *ndrd;
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struct nd_region *nd_region = to_nd_region(dev);
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if (nd_region->num_lanes > num_online_cpus()
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&& nd_region->num_lanes < num_possible_cpus()
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&& !test_and_set_bit(0, &once)) {
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dev_dbg(dev, "online cpus (%d) < concurrent i/o lanes (%d) < possible cpus (%d)\n",
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num_online_cpus(), nd_region->num_lanes,
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num_possible_cpus());
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dev_dbg(dev, "setting nr_cpus=%d may yield better libnvdimm device performance\n",
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nd_region->num_lanes);
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}
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rc = nd_region_activate(nd_region);
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if (rc)
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return rc;
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rc = nd_blk_region_init(nd_region);
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if (rc)
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return rc;
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if (is_nd_pmem(&nd_region->dev)) {
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struct resource ndr_res;
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if (devm_init_badblocks(dev, &nd_region->bb))
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return -ENODEV;
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nd_region->bb_state = sysfs_get_dirent(nd_region->dev.kobj.sd,
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"badblocks");
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if (!nd_region->bb_state)
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dev_warn(&nd_region->dev,
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"'badblocks' notification disabled\n");
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ndr_res.start = nd_region->ndr_start;
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ndr_res.end = nd_region->ndr_start + nd_region->ndr_size - 1;
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nvdimm_badblocks_populate(nd_region, &nd_region->bb, &ndr_res);
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}
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rc = nd_region_register_namespaces(nd_region, &err);
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if (rc < 0)
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return rc;
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ndrd = dev_get_drvdata(dev);
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ndrd->ns_active = rc;
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ndrd->ns_count = rc + err;
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if (rc && err && rc == err)
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return -ENODEV;
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nd_region->btt_seed = nd_btt_create(nd_region);
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nd_region->pfn_seed = nd_pfn_create(nd_region);
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nd_region->dax_seed = nd_dax_create(nd_region);
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if (err == 0)
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return 0;
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/*
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* Given multiple namespaces per region, we do not want to
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* disable all the successfully registered peer namespaces upon
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* a single registration failure. If userspace is missing a
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* namespace that it expects it can disable/re-enable the region
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* to retry discovery after correcting the failure.
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* <regionX>/namespaces returns the current
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* "<async-registered>/<total>" namespace count.
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*/
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dev_err(dev, "failed to register %d namespace%s, continuing...\n",
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err, err == 1 ? "" : "s");
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return 0;
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}
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static int child_unregister(struct device *dev, void *data)
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{
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nd_device_unregister(dev, ND_SYNC);
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return 0;
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}
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static int nd_region_remove(struct device *dev)
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{
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struct nd_region *nd_region = to_nd_region(dev);
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device_for_each_child(dev, NULL, child_unregister);
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/* flush attribute readers and disable */
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nvdimm_bus_lock(dev);
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nd_region->ns_seed = NULL;
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nd_region->btt_seed = NULL;
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nd_region->pfn_seed = NULL;
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nd_region->dax_seed = NULL;
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dev_set_drvdata(dev, NULL);
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nvdimm_bus_unlock(dev);
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/*
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* Note, this assumes nd_device_lock() context to not race
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* nd_region_notify()
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*/
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sysfs_put(nd_region->bb_state);
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nd_region->bb_state = NULL;
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return 0;
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}
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static int child_notify(struct device *dev, void *data)
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{
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nd_device_notify(dev, *(enum nvdimm_event *) data);
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return 0;
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}
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static void nd_region_notify(struct device *dev, enum nvdimm_event event)
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{
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if (event == NVDIMM_REVALIDATE_POISON) {
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struct nd_region *nd_region = to_nd_region(dev);
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struct resource res;
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if (is_nd_pmem(&nd_region->dev)) {
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res.start = nd_region->ndr_start;
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res.end = nd_region->ndr_start +
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nd_region->ndr_size - 1;
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nvdimm_badblocks_populate(nd_region,
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&nd_region->bb, &res);
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if (nd_region->bb_state)
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sysfs_notify_dirent(nd_region->bb_state);
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}
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}
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device_for_each_child(dev, &event, child_notify);
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}
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static struct nd_device_driver nd_region_driver = {
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.probe = nd_region_probe,
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.remove = nd_region_remove,
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.notify = nd_region_notify,
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.drv = {
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.name = "nd_region",
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},
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.type = ND_DRIVER_REGION_BLK | ND_DRIVER_REGION_PMEM,
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};
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int __init nd_region_init(void)
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{
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return nd_driver_register(&nd_region_driver);
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}
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void nd_region_exit(void)
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{
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driver_unregister(&nd_region_driver.drv);
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}
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MODULE_ALIAS_ND_DEVICE(ND_DEVICE_REGION_PMEM);
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MODULE_ALIAS_ND_DEVICE(ND_DEVICE_REGION_BLK);
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