nvdimm: Replace lockdep_mutex with local lock classes

In response to an attempt to expand dev->lockdep_mutex for device_lock()
validation [1], Peter points out [2] that the lockdep API already has
the ability to assign a dedicated lock class per subsystem device-type.

Use lockdep_set_class() to override the default device_lock()
'__lockdep_no_validate__' class for each NVDIMM subsystem device-type. This
enables lockdep to detect deadlocks and recursive locking within the
device-driver core and the subsystem.

Link: https://lore.kernel.org/r/[e-mail] [1]
Link: https://lore.kernel.org/r/[e-mail] [2]
Suggested-by: Peter Zijlstra <[e-mail]>
Cc: Vishal Verma <[e-mail]>
Cc: Dave Jiang <[e-mail]>
Cc: Ira Weiny <[e-mail]>
Reviewed-by: Ira Weiny <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Dan Williams <[e-mail]>

drivers/nvdimm/btt_devs.c

···
 }
 EXPORT_SYMBOL(is_nd_btt);
 
+static struct lock_class_key nvdimm_btt_key;
+
 static struct device *__nd_btt_create(struct nd_region *nd_region,
 				      unsigned long lbasize, uuid_t *uuid,
 				      struct nd_namespace_common *ndns)
···
 	dev->parent = &nd_region->dev;
 	dev->type = &nd_btt_device_type;
 	device_initialize(&nd_btt->dev);
+	lockdep_set_class(&nd_btt->dev.mutex, &nvdimm_btt_key);
 	if (ndns && !__nd_attach_ndns(&nd_btt->dev, ndns, &nd_btt->ndns)) {
 		dev_dbg(&ndns->dev, "failed, already claimed by %s\n",
 				dev_name(ndns->claim));
···
 {
 	struct device *dev = __nd_btt_create(nd_region, 0, NULL, NULL);
 
-	__nd_device_register(dev);
+	nd_device_register(dev);
 	return dev;
 }
 
···
 	if (!nd_btt->uuid)
 		return -ENOMEM;
 
-	__nd_device_register(&nd_btt->dev);
+	nd_device_register(&nd_btt->dev);
 
 	return 0;
 }

drivers/nvdimm/bus.c

···
 }
 EXPORT_SYMBOL_GPL(nvdimm_to_bus);
 
+static struct lock_class_key nvdimm_bus_key;
+
 struct nvdimm_bus *nvdimm_bus_register(struct device *parent,
 		struct nvdimm_bus_descriptor *nd_desc)
 {
···
 	nvdimm_bus->dev.bus = &nvdimm_bus_type;
 	nvdimm_bus->dev.of_node = nd_desc->of_node;
 	device_initialize(&nvdimm_bus->dev);
+	lockdep_set_class(&nvdimm_bus->dev.mutex, &nvdimm_bus_key);
 	device_set_pm_not_required(&nvdimm_bus->dev);
 	rc = dev_set_name(&nvdimm_bus->dev, "ndbus%d", nvdimm_bus->id);
 	if (rc)
···
 	put_device(dev);
 }
 
-void __nd_device_register(struct device *dev)
+void nd_device_register(struct device *dev)
 {
 	if (!dev)
 		return;
···
 
 	async_schedule_dev_domain(nd_async_device_register, dev,
 				  &nd_async_domain);
-}
-
-void nd_device_register(struct device *dev)
-{
-	device_initialize(dev);
-	__nd_device_register(dev);
 }
 EXPORT_SYMBOL(nd_device_register);
 
···
 	kfree(dev);
 }
 
+static struct lock_class_key nvdimm_ndctl_key;
+
 int nvdimm_bus_create_ndctl(struct nvdimm_bus *nvdimm_bus)
 {
 	dev_t devt = MKDEV(nvdimm_bus_major, nvdimm_bus->id);
···
 	if (!dev)
 		return -ENOMEM;
 	device_initialize(dev);
+	lockdep_set_class(&dev->mutex, &nvdimm_ndctl_key);
 	device_set_pm_not_required(dev);
 	dev->class = nd_class;
 	dev->parent = &nvdimm_bus->dev;

drivers/nvdimm/dax_devs.c

···
 	nd_dax = nd_dax_alloc(nd_region);
 	if (nd_dax)
 		dev = nd_pfn_devinit(&nd_dax->nd_pfn, NULL);
-	__nd_device_register(dev);
+	nd_device_register(dev);
 	return dev;
 }
 
···
 		nd_detach_ndns(dax_dev, &nd_pfn->ndns);
 		put_device(dax_dev);
 	} else
-		__nd_device_register(dax_dev);
+		nd_device_register(dax_dev);
 
 	return rc;
 }

drivers/nvdimm/dimm_devs.c

···
 	return dev->type == &nvdimm_device_type;
 }
 
+static struct lock_class_key nvdimm_key;
+
 struct nvdimm *__nvdimm_create(struct nvdimm_bus *nvdimm_bus,
 		void *provider_data, const struct attribute_group **groups,
 		unsigned long flags, unsigned long cmd_mask, int num_flush,
···
 	/* get security state and extended (master) state */
 	nvdimm->sec.flags = nvdimm_security_flags(nvdimm, NVDIMM_USER);
 	nvdimm->sec.ext_flags = nvdimm_security_flags(nvdimm, NVDIMM_MASTER);
+	device_initialize(dev);
+	lockdep_set_class(&dev->mutex, &nvdimm_key);
 	nd_device_register(dev);
 
 	return nvdimm;

drivers/nvdimm/namespace_devs.c

···
 	return dev;
 }
 
+static struct lock_class_key nvdimm_namespace_key;
+
 void nd_region_create_ns_seed(struct nd_region *nd_region)
 {
 	WARN_ON(!is_nvdimm_bus_locked(&nd_region->dev));
···
 	 */
 	if (!nd_region->ns_seed)
 		dev_err(&nd_region->dev, "failed to create namespace\n");
-	else
+	else {
+		device_initialize(nd_region->ns_seed);
+		lockdep_set_class(&nd_region->ns_seed->mutex,
+				  &nvdimm_namespace_key);
 		nd_device_register(nd_region->ns_seed);
+	}
 }
 
 void nd_region_create_dax_seed(struct nd_region *nd_region)
···
 		if (id < 0)
 			break;
 		dev_set_name(dev, "namespace%d.%d", nd_region->id, id);
+		device_initialize(dev);
+		lockdep_set_class(&dev->mutex, &nvdimm_namespace_key);
 		nd_device_register(dev);
 	}
 	if (i)

drivers/nvdimm/nd-core.h

···
 int nvdimm_bus_create_ndctl(struct nvdimm_bus *nvdimm_bus);
 void nvdimm_bus_destroy_ndctl(struct nvdimm_bus *nvdimm_bus);
 void nd_synchronize(void);
-void __nd_device_register(struct device *dev);
+void nd_device_register(struct device *dev);
 struct nd_label_id;
 char *nd_label_gen_id(struct nd_label_id *label_id, const uuid_t *uuid,
 		      u32 flags);

drivers/nvdimm/pfn_devs.c

···
 }
 EXPORT_SYMBOL(is_nd_pfn);
 
+static struct lock_class_key nvdimm_pfn_key;
+
 struct device *nd_pfn_devinit(struct nd_pfn *nd_pfn,
 		struct nd_namespace_common *ndns)
 {
···
 	nd_pfn->align = nd_pfn_default_alignment();
 	dev = &nd_pfn->dev;
 	device_initialize(&nd_pfn->dev);
+	lockdep_set_class(&nd_pfn->dev.mutex, &nvdimm_pfn_key);
 	if (ndns && !__nd_attach_ndns(&nd_pfn->dev, ndns, &nd_pfn->ndns)) {
 		dev_dbg(&ndns->dev, "failed, already claimed by %s\n",
 				dev_name(ndns->claim));
···
 	nd_pfn = nd_pfn_alloc(nd_region);
 	dev = nd_pfn_devinit(nd_pfn, NULL);
 
-	__nd_device_register(dev);
+	nd_device_register(dev);
 	return dev;
 }
 
···
 		nd_detach_ndns(pfn_dev, &nd_pfn->ndns);
 		put_device(pfn_dev);
 	} else
-		__nd_device_register(pfn_dev);
+		nd_device_register(pfn_dev);
 
 	return rc;
 }

drivers/nvdimm/region_devs.c

···
 	return align;
 }
 
+static struct lock_class_key nvdimm_region_key;
+
 static struct nd_region *nd_region_create(struct nvdimm_bus *nvdimm_bus,
 		struct nd_region_desc *ndr_desc,
 		const struct device_type *dev_type, const char *caller)
···
 	else
 		nd_region->flush = NULL;
 
+	device_initialize(dev);
+	lockdep_set_class(&dev->mutex, &nvdimm_region_key);
 	nd_device_register(dev);
 
 	return nd_region;