[PATCH v4 1/4] 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(a)intel.com&gt; Signed-off-by: Dan Williams <dan.j.williams(a)intel.com&gt; --- drivers/nvdimm/bus.c | 188 +++++++++++++++++++++++++++++++++++++++++++++++-- drivers/nvdimm/core.c | 127 --------------------------------- 2 files changed, 181 insertions(+), 134 deletions(-) diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c index 275dd5c0a301..46d7e555b044 100644 --- a/drivers/nvdimm/bus.c +++ b/drivers/nvdimm/bus.c @@ -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); } diff --git a/drivers/nvdimm/core.c b/drivers/nvdimm/core.c index e8528756f54f..2c98f958fabb 100644 --- a/drivers/nvdimm/core.c +++ b/drivers/nvdimm/core.c @@ -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");