NVMe: Export namespace attributes to sysfs

Exposes the NGUID, EUI-64, and NSID to sysfs entries under the disk's
kobject.
Signed-off-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

drivers/nvme/host/core.c

@@ -574,6 +574,11 @@ static int nvme_revalidate_disk(struct gendisk *disk)
 		ns->type = NVME_NS_LIGHTNVM;
 	}
 
+	if (ns->ctrl->vs >= NVME_VS(1, 1))
+		memcpy(ns->eui, id->eui64, sizeof(ns->eui));
+	if (ns->ctrl->vs >= NVME_VS(1, 2))
+		memcpy(ns->uuid, id->nguid, sizeof(ns->uuid));
+
 	old_ms = ns->ms;
 	lbaf = id->flbas & NVME_NS_FLBAS_LBA_MASK;
 	ns->lba_shift = id->lbaf[lbaf].ds;
@@ -964,6 +969,59 @@ static ssize_t nvme_sysfs_reset(struct device *dev,
 }
 static DEVICE_ATTR(reset_controller, S_IWUSR, NULL, nvme_sysfs_reset);
 
+static ssize_t uuid_show(struct device *dev, struct device_attribute *attr,
+								char *buf)
+{
+	struct nvme_ns *ns = dev_to_disk(dev)->private_data;
+	return sprintf(buf, "%pU\n", ns->uuid);
+}
+static DEVICE_ATTR(uuid, S_IRUGO, uuid_show, NULL);
+
+static ssize_t eui_show(struct device *dev, struct device_attribute *attr,
+								char *buf)
+{
+	struct nvme_ns *ns = dev_to_disk(dev)->private_data;
+	return sprintf(buf, "%8phd\n", ns->eui);
+}
+static DEVICE_ATTR(eui, S_IRUGO, eui_show, NULL);
+
+static ssize_t nsid_show(struct device *dev, struct device_attribute *attr,
+								char *buf)
+{
+	struct nvme_ns *ns = dev_to_disk(dev)->private_data;
+	return sprintf(buf, "%d\n", ns->ns_id);
+}
+static DEVICE_ATTR(nsid, S_IRUGO, nsid_show, NULL);
+
+static struct attribute *nvme_ns_attrs[] = {
+	&dev_attr_uuid.attr,
+	&dev_attr_eui.attr,
+	&dev_attr_nsid.attr,
+	NULL,
+};
+
+static umode_t nvme_attrs_are_visible(struct kobject *kobj,
+		struct attribute *a, int n)
+{
+	struct device *dev = container_of(kobj, struct device, kobj);
+	struct nvme_ns *ns = dev_to_disk(dev)->private_data;
+
+	if (a == &dev_attr_uuid.attr) {
+		if (!memchr_inv(ns->uuid, 0, sizeof(ns->uuid)))
+			return 0;
+	}
+	if (a == &dev_attr_eui.attr) {
+		if (!memchr_inv(ns->eui, 0, sizeof(ns->eui)))
+			return 0;
+	}
+	return a->mode;
+}
+
+static const struct attribute_group nvme_ns_attr_group = {
+	.attrs		= nvme_ns_attrs,
+	.is_visible	= nvme_attrs_are_visible,
+};
+
 static int ns_cmp(void *priv, struct list_head *a, struct list_head *b)
 {
 	struct nvme_ns *nsa = container_of(a, struct nvme_ns, list);
@@ -1038,9 +1096,14 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 
 	list_add_tail(&ns->list, &ctrl->namespaces);
 	kref_get(&ctrl->kref);
-	if (ns->type != NVME_NS_LIGHTNVM)
-		add_disk(ns->disk);
+	if (ns->type == NVME_NS_LIGHTNVM)
+		return;
 
+	add_disk(ns->disk);
+	if (sysfs_create_group(&disk_to_dev(ns->disk)->kobj,
+					&nvme_ns_attr_group))
+		pr_warn("%s: failed to create sysfs group for identification\n",
+			ns->disk->disk_name);
 	return;
  out_free_disk:
 	kfree(disk);
@@ -1060,6 +1123,8 @@ static void nvme_ns_remove(struct nvme_ns *ns)
 	if (ns->disk->flags & GENHD_FL_UP) {
 		if (blk_get_integrity(ns->disk))
 			blk_integrity_unregister(ns->disk);
+		sysfs_remove_group(&disk_to_dev(ns->disk)->kobj,
+					&nvme_ns_attr_group);
 		del_gendisk(ns->disk);
 	}
 	if (kill || !blk_queue_dying(ns->queue)) {

drivers/nvme/host/nvme.h

@@ -102,6 +102,9 @@ struct nvme_ns {
 	struct gendisk *disk;
 	struct kref kref;
 
+	u8 eui[8];
+	u8 uuid[16];
+
 	unsigned ns_id;
 	int lba_shift;
 	u16 ms;