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Commit 18515942 authored by Dan Williams's avatar Dan Williams
Browse files

libnvdimm: register nvdimm_bus devices with an nd_bus driver 



A recent effort to add a new nvdimm bus provider attribute highlighted a
race between interrogating nvdimm_bus->nd_desc and nvdimm_bus tear down.
The typical way to handle these races is to take the device_lock() in
the attribute method and validate that the device is still active.  In
order for a device to be 'active' it needs to be associated with a
driver.  So, we create the small boilerplate for a driver and register
nvdimm_bus devices on the 'nvdimm_bus_type' bus.

A result of this change is that ndbusX devices now appear under
/sys/bus/nd/devices.  In fact this makes /sys/class/nd somewhat
redundant, but removing that will need to take a long deprecation period
given its use by ndctl binaries in the field.

This change naturally pulls code from drivers/nvdimm/core.c to
drivers/nvdimm/bus.c, so it is a nice code organization clean-up as
well.

Cc: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 5bf0b6e1

drivers/nvdimm/bus.c

+181 −7
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ 
int nvdimm_major;

static int nvdimm_bus_major;

static struct class *nd_class;

static DEFINE_IDA(nd_ida);



static int to_nd_device_type(struct device *dev)

{
@@ -60,13 +61,6 @@ static int nvdimm_bus_uevent(struct device *dev, struct kobj_uevent_env *env) 
			to_nd_device_type(dev));

}



static int nvdimm_bus_match(struct device *dev, struct device_driver *drv)

{

	struct nd_device_driver *nd_drv = to_nd_device_driver(drv);



	return !!test_bit(to_nd_device_type(dev), &nd_drv->type);

}



static struct module *to_bus_provider(struct device *dev)

{

	/* pin bus providers while regions are enabled */
@@ -223,6 +217,8 @@ long nvdimm_clear_poison(struct device *dev, phys_addr_t phys, 
}

EXPORT_SYMBOL_GPL(nvdimm_clear_poison);



static int nvdimm_bus_match(struct device *dev, struct device_driver *drv);



static struct bus_type nvdimm_bus_type = {

	.name = "nd",

	.uevent = nvdimm_bus_uevent,
@@ -232,6 +228,176 @@ static struct bus_type nvdimm_bus_type = { 
	.shutdown = nvdimm_bus_shutdown,

};



static void nvdimm_bus_release(struct device *dev)

{

	struct nvdimm_bus *nvdimm_bus;



	nvdimm_bus = container_of(dev, struct nvdimm_bus, dev);

	ida_simple_remove(&nd_ida, nvdimm_bus->id);

	kfree(nvdimm_bus);

}



static bool is_nvdimm_bus(struct device *dev)

{

	return dev->release == nvdimm_bus_release;

}



struct nvdimm_bus *walk_to_nvdimm_bus(struct device *nd_dev)

{

	struct device *dev;



	for (dev = nd_dev; dev; dev = dev->parent)

		if (is_nvdimm_bus(dev))

			break;

	dev_WARN_ONCE(nd_dev, !dev, "invalid dev, not on nd bus\n");

	if (dev)

		return to_nvdimm_bus(dev);

	return NULL;

}



struct nvdimm_bus *to_nvdimm_bus(struct device *dev)

{

	struct nvdimm_bus *nvdimm_bus;



	nvdimm_bus = container_of(dev, struct nvdimm_bus, dev);

	WARN_ON(!is_nvdimm_bus(dev));

	return nvdimm_bus;

}

EXPORT_SYMBOL_GPL(to_nvdimm_bus);



struct nvdimm_bus *nvdimm_bus_register(struct device *parent,

		struct nvdimm_bus_descriptor *nd_desc)

{

	struct nvdimm_bus *nvdimm_bus;

	int rc;



	nvdimm_bus = kzalloc(sizeof(*nvdimm_bus), GFP_KERNEL);

	if (!nvdimm_bus)

		return NULL;

	INIT_LIST_HEAD(&nvdimm_bus->list);

	INIT_LIST_HEAD(&nvdimm_bus->mapping_list);

	INIT_LIST_HEAD(&nvdimm_bus->poison_list);

	init_waitqueue_head(&nvdimm_bus->probe_wait);

	nvdimm_bus->id = ida_simple_get(&nd_ida, 0, 0, GFP_KERNEL);

	mutex_init(&nvdimm_bus->reconfig_mutex);

	if (nvdimm_bus->id < 0) {

		kfree(nvdimm_bus);

		return NULL;

	}

	nvdimm_bus->nd_desc = nd_desc;

	nvdimm_bus->dev.parent = parent;

	nvdimm_bus->dev.release = nvdimm_bus_release;

	nvdimm_bus->dev.groups = nd_desc->attr_groups;

	nvdimm_bus->dev.bus = &nvdimm_bus_type;

	dev_set_name(&nvdimm_bus->dev, "ndbus%d", nvdimm_bus->id);

	rc = device_register(&nvdimm_bus->dev);

	if (rc) {

		dev_dbg(&nvdimm_bus->dev, "registration failed: %d\n", rc);

		goto err;

	}



	return nvdimm_bus;

 err:

	put_device(&nvdimm_bus->dev);

	return NULL;

}

EXPORT_SYMBOL_GPL(nvdimm_bus_register);



void nvdimm_bus_unregister(struct nvdimm_bus *nvdimm_bus)

{

	if (!nvdimm_bus)

		return;

	device_unregister(&nvdimm_bus->dev);

}

EXPORT_SYMBOL_GPL(nvdimm_bus_unregister);



static int child_unregister(struct device *dev, void *data)

{

	/*

	 * the singular ndctl class device per bus needs to be

	 * "device_destroy"ed, so skip it here

	 *

	 * i.e. remove classless children

	 */

	if (dev->class)

		/* pass */;

	else

		nd_device_unregister(dev, ND_SYNC);

	return 0;

}



static void free_poison_list(struct list_head *poison_list)

{

	struct nd_poison *pl, *next;



	list_for_each_entry_safe(pl, next, poison_list, list) {

		list_del(&pl->list);

		kfree(pl);

	}

	list_del_init(poison_list);

}



static int nd_bus_remove(struct device *dev)

{

	struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);



	mutex_lock(&nvdimm_bus_list_mutex);

	list_del_init(&nvdimm_bus->list);

	mutex_unlock(&nvdimm_bus_list_mutex);



	nd_synchronize();

	device_for_each_child(&nvdimm_bus->dev, NULL, child_unregister);



	nvdimm_bus_lock(&nvdimm_bus->dev);

	free_poison_list(&nvdimm_bus->poison_list);

	nvdimm_bus_unlock(&nvdimm_bus->dev);



	nvdimm_bus_destroy_ndctl(nvdimm_bus);



	return 0;

}



static int nd_bus_probe(struct device *dev)

{

	struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);

	int rc;



	rc = nvdimm_bus_create_ndctl(nvdimm_bus);

	if (rc)

		return rc;



	mutex_lock(&nvdimm_bus_list_mutex);

	list_add_tail(&nvdimm_bus->list, &nvdimm_bus_list);

	mutex_unlock(&nvdimm_bus_list_mutex);



	/* enable bus provider attributes to look up their local context */

	dev_set_drvdata(dev, nvdimm_bus->nd_desc);



	return 0;

}



static struct nd_device_driver nd_bus_driver = {

	.probe = nd_bus_probe,

	.remove = nd_bus_remove,

	.drv = {

		.name = "nd_bus",

		.suppress_bind_attrs = true,

		.bus = &nvdimm_bus_type,

		.owner = THIS_MODULE,

		.mod_name = KBUILD_MODNAME,

	},

};



static int nvdimm_bus_match(struct device *dev, struct device_driver *drv)

{

	struct nd_device_driver *nd_drv = to_nd_device_driver(drv);



	if (is_nvdimm_bus(dev) && nd_drv == &nd_bus_driver)

		return true;



	return !!test_bit(to_nd_device_type(dev), &nd_drv->type);

}



static ASYNC_DOMAIN_EXCLUSIVE(nd_async_domain);



void nd_synchronize(void)
@@ -864,8 +1030,14 @@ int __init nvdimm_bus_init(void) 
		goto err_class;

	}



	rc = driver_register(&nd_bus_driver.drv);

	if (rc)

		goto err_nd_bus;



	return 0;



 err_nd_bus:

	class_destroy(nd_class);

 err_class:

	unregister_chrdev(nvdimm_major, "dimmctl");

 err_dimm_chrdev:
@@ -878,8 +1050,10 @@ int __init nvdimm_bus_init(void) 


void nvdimm_bus_exit(void)

{

	driver_unregister(&nd_bus_driver.drv);

	class_destroy(nd_class);

	unregister_chrdev(nvdimm_bus_major, "ndctl");

	unregister_chrdev(nvdimm_major, "dimmctl");

	bus_unregister(&nvdimm_bus_type);

	ida_destroy(&nd_ida);

}

drivers/nvdimm/core.c

+0 −127
Original line number Diff line number Diff line
@@ -26,7 +26,6 @@ 


LIST_HEAD(nvdimm_bus_list);

DEFINE_MUTEX(nvdimm_bus_list_mutex);

static DEFINE_IDA(nd_ida);



void nvdimm_bus_lock(struct device *dev)

{
@@ -195,25 +194,6 @@ u64 nd_fletcher64(void *addr, size_t len, bool le) 
}

EXPORT_SYMBOL_GPL(nd_fletcher64);



static void nvdimm_bus_release(struct device *dev)

{

	struct nvdimm_bus *nvdimm_bus;



	nvdimm_bus = container_of(dev, struct nvdimm_bus, dev);

	ida_simple_remove(&nd_ida, nvdimm_bus->id);

	kfree(nvdimm_bus);

}



struct nvdimm_bus *to_nvdimm_bus(struct device *dev)

{

	struct nvdimm_bus *nvdimm_bus;



	nvdimm_bus = container_of(dev, struct nvdimm_bus, dev);

	WARN_ON(nvdimm_bus->dev.release != nvdimm_bus_release);

	return nvdimm_bus;

}

EXPORT_SYMBOL_GPL(to_nvdimm_bus);



struct nvdimm_bus_descriptor *to_nd_desc(struct nvdimm_bus *nvdimm_bus)

{

	/* struct nvdimm_bus definition is private to libnvdimm */
@@ -221,19 +201,6 @@ struct nvdimm_bus_descriptor *to_nd_desc(struct nvdimm_bus *nvdimm_bus) 
}

EXPORT_SYMBOL_GPL(to_nd_desc);



struct nvdimm_bus *walk_to_nvdimm_bus(struct device *nd_dev)

{

	struct device *dev;



	for (dev = nd_dev; dev; dev = dev->parent)

		if (dev->release == nvdimm_bus_release)

			break;

	dev_WARN_ONCE(nd_dev, !dev, "invalid dev, not on nd bus\n");

	if (dev)

		return to_nvdimm_bus(dev);

	return NULL;

}



static bool is_uuid_sep(char sep)

{

	if (sep == '\n' || sep == '-' || sep == ':' || sep == '\0')
@@ -447,51 +414,6 @@ struct attribute_group nvdimm_bus_attribute_group = { 
};

EXPORT_SYMBOL_GPL(nvdimm_bus_attribute_group);



struct nvdimm_bus *nvdimm_bus_register(struct device *parent,

		struct nvdimm_bus_descriptor *nd_desc)

{

	struct nvdimm_bus *nvdimm_bus;

	int rc;



	nvdimm_bus = kzalloc(sizeof(*nvdimm_bus), GFP_KERNEL);

	if (!nvdimm_bus)

		return NULL;

	INIT_LIST_HEAD(&nvdimm_bus->list);

	INIT_LIST_HEAD(&nvdimm_bus->mapping_list);

	INIT_LIST_HEAD(&nvdimm_bus->poison_list);

	init_waitqueue_head(&nvdimm_bus->probe_wait);

	nvdimm_bus->id = ida_simple_get(&nd_ida, 0, 0, GFP_KERNEL);

	mutex_init(&nvdimm_bus->reconfig_mutex);

	if (nvdimm_bus->id < 0) {

		kfree(nvdimm_bus);

		return NULL;

	}

	nvdimm_bus->nd_desc = nd_desc;

	nvdimm_bus->dev.parent = parent;

	nvdimm_bus->dev.release = nvdimm_bus_release;

	nvdimm_bus->dev.groups = nd_desc->attr_groups;

	dev_set_name(&nvdimm_bus->dev, "ndbus%d", nvdimm_bus->id);

	rc = device_register(&nvdimm_bus->dev);

	if (rc) {

		dev_dbg(&nvdimm_bus->dev, "registration failed: %d\n", rc);

		goto err;

	}



	rc = nvdimm_bus_create_ndctl(nvdimm_bus);

	if (rc)

		goto err;



	mutex_lock(&nvdimm_bus_list_mutex);

	list_add_tail(&nvdimm_bus->list, &nvdimm_bus_list);

	mutex_unlock(&nvdimm_bus_list_mutex);



	return nvdimm_bus;

 err:

	put_device(&nvdimm_bus->dev);

	return NULL;

}

EXPORT_SYMBOL_GPL(nvdimm_bus_register);



static void set_badblock(struct badblocks *bb, sector_t s, int num)

{

	dev_dbg(bb->dev, "Found a poison range (0x%llx, 0x%llx)\n",
@@ -667,54 +589,6 @@ int nvdimm_bus_add_poison(struct nvdimm_bus *nvdimm_bus, u64 addr, u64 length) 
}

EXPORT_SYMBOL_GPL(nvdimm_bus_add_poison);



static void free_poison_list(struct list_head *poison_list)

{

	struct nd_poison *pl, *next;



	list_for_each_entry_safe(pl, next, poison_list, list) {

		list_del(&pl->list);

		kfree(pl);

	}

	list_del_init(poison_list);

}



static int child_unregister(struct device *dev, void *data)

{

	/*

	 * the singular ndctl class device per bus needs to be

	 * "device_destroy"ed, so skip it here

	 *

	 * i.e. remove classless children

	 */

	if (dev->class)

		/* pass */;

	else

		nd_device_unregister(dev, ND_SYNC);

	return 0;

}



void nvdimm_bus_unregister(struct nvdimm_bus *nvdimm_bus)

{

	if (!nvdimm_bus)

		return;



	mutex_lock(&nvdimm_bus_list_mutex);

	list_del_init(&nvdimm_bus->list);

	mutex_unlock(&nvdimm_bus_list_mutex);



	nd_synchronize();

	device_for_each_child(&nvdimm_bus->dev, NULL, child_unregister);



	nvdimm_bus_lock(&nvdimm_bus->dev);

	free_poison_list(&nvdimm_bus->poison_list);

	nvdimm_bus_unlock(&nvdimm_bus->dev);



	nvdimm_bus_destroy_ndctl(nvdimm_bus);



	device_unregister(&nvdimm_bus->dev);

}

EXPORT_SYMBOL_GPL(nvdimm_bus_unregister);



#ifdef CONFIG_BLK_DEV_INTEGRITY

int nd_integrity_init(struct gendisk *disk, unsigned long meta_size)

{
@@ -773,7 +647,6 @@ static __exit void libnvdimm_exit(void) 
	nvdimm_bus_exit();

	nd_region_devs_exit();

	nvdimm_devs_exit();

	ida_destroy(&nd_ida);

}



MODULE_LICENSE("GPL v2");