configfs: switch ->default groups to a linked list

Replace the current NULL-terminated array of default groups with a linked
list.  This gets rid of lots of nasty code to size and/or dynamically
allocate the array.

While we're at it also provide a conveniant helper to remove the default
groups.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Felipe Balbi <balbi@kernel.org>		[drivers/usb/gadget]
Acked-by: Joel Becker <jlbec@evilplan.org>
Acked-by: Nicholas Bellinger <nab@linux-iscsi.org>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>

10 files changed, 237 insertions, 553 deletions

diff --git a/drivers/infiniband/core/cma_configfs.c b/drivers/infiniband/core/cma_configfs.c
index 18b112aa577e..41573df1d9fc 100644
--- a/drivers/infiniband/core/cma_configfs.c
+++ b/drivers/infiniband/core/cma_configfs.c
@@ -49,8 +49,6 @@ struct cma_dev_group {
 	char				name[IB_DEVICE_NAME_MAX];
 	struct config_group		device_group;
 	struct config_group		ports_group;
-	struct config_group		*default_dev_group[2];
-	struct config_group		**default_ports_group;
 	struct cma_dev_port_group	*ports;
 };
 
@@ -158,7 +156,6 @@ static int make_cma_ports(struct cma_dev_group *cma_dev_group,
 	unsigned int i;
 	unsigned int ports_num;
 	struct cma_dev_port_group *ports;
-	struct config_group **ports_group;
 	int err;
 
 	ibdev = cma_get_ib_dev(cma_dev);
@@ -169,9 +166,8 @@ static int make_cma_ports(struct cma_dev_group *cma_dev_group,
 	ports_num = ibdev->phys_port_cnt;
 	ports = kcalloc(ports_num, sizeof(*cma_dev_group->ports),
 			GFP_KERNEL);
-	ports_group = kcalloc(ports_num + 1, sizeof(*ports_group), GFP_KERNEL);
 
-	if (!ports || !ports_group) {
+	if (!ports) {
 		err = -ENOMEM;
 		goto free;
 	}
@@ -185,18 +181,16 @@ static int make_cma_ports(struct cma_dev_group *cma_dev_group,
 		config_group_init_type_name(&ports[i].group,
 					    port_str,
 					    &cma_port_group_type);
-		ports_group[i] = &ports[i].group;
+		configfs_add_default_group(&ports[i].group,
+				&cma_dev_group->ports_group);
+
 	}
-	ports_group[i] = NULL;
-	cma_dev_group->default_ports_group = ports_group;
 	cma_dev_group->ports = ports;
 
 	return 0;
 free:
 	kfree(ports);
-	kfree(ports_group);
 	cma_dev_group->ports = NULL;
-	cma_dev_group->default_ports_group = NULL;
 	return err;
 }
 
@@ -220,9 +214,7 @@ static void release_cma_ports_group(struct config_item  *item)
 							   ports_group);
 
 	kfree(cma_dev_group->ports);
-	kfree(cma_dev_group->default_ports_group);
 	cma_dev_group->ports = NULL;
-	cma_dev_group->default_ports_group = NULL;
 };
 
 static struct configfs_item_operations cma_ports_item_ops = {
@@ -263,22 +255,17 @@ static struct config_group *make_cma_dev(struct config_group *group,
 
 	strncpy(cma_dev_group->name, name, sizeof(cma_dev_group->name));
 
-	err = make_cma_ports(cma_dev_group, cma_dev);
-	if (err)
-		goto fail;
-
-	cma_dev_group->ports_group.default_groups =
-		cma_dev_group->default_ports_group;
 	config_group_init_type_name(&cma_dev_group->ports_group, "ports",
 				    &cma_ports_group_type);
 
-	cma_dev_group->device_group.default_groups
-		= cma_dev_group->default_dev_group;
-	cma_dev_group->default_dev_group[0] = &cma_dev_group->ports_group;
-	cma_dev_group->default_dev_group[1] = NULL;
+	err = make_cma_ports(cma_dev_group, cma_dev);
+	if (err)
+		goto fail;
 
 	config_group_init_type_name(&cma_dev_group->device_group, name,
 				    &cma_device_group_type);
+	configfs_add_default_group(&cma_dev_group->ports_group,
+			&cma_dev_group->device_group);
 
 	cma_deref_dev(cma_dev);
 	return &cma_dev_group->device_group;
diff --git a/drivers/target/iscsi/iscsi_target_configfs.c b/drivers/target/iscsi/iscsi_target_configfs.c
index 2f821de63049..a24443ba59ea 100644
--- a/drivers/target/iscsi/iscsi_target_configfs.c
+++ b/drivers/target/iscsi/iscsi_target_configfs.c
@@ -771,21 +771,11 @@ static int lio_target_init_nodeacl(struct se_node_acl *se_nacl,
 {
 	struct iscsi_node_acl *acl =
 		container_of(se_nacl, struct iscsi_node_acl, se_node_acl);
-	struct config_group *stats_cg = &se_nacl->acl_fabric_stat_group;
-
-	stats_cg->default_groups = kmalloc(sizeof(struct config_group *) * 2,
-				GFP_KERNEL);
-	if (!stats_cg->default_groups) {
-		pr_err("Unable to allocate memory for"
-				" stats_cg->default_groups\n");
-		return -ENOMEM;
-	}
 
-	stats_cg->default_groups[0] = &acl->node_stat_grps.iscsi_sess_stats_group;
-	stats_cg->default_groups[1] = NULL;
 	config_group_init_type_name(&acl->node_stat_grps.iscsi_sess_stats_group,
 			"iscsi_sess_stats", &iscsi_stat_sess_cit);
-
+	configfs_add_default_group(&acl->node_stat_grps.iscsi_sess_stats_group,
+			&se_nacl->acl_fabric_stat_group);
 	return 0;
 }
 
@@ -793,17 +783,8 @@ static void lio_target_cleanup_nodeacl( struct se_node_acl *se_nacl)
 {
 	struct iscsi_node_acl *acl = container_of(se_nacl,
 			struct iscsi_node_acl, se_node_acl);
-	struct config_item *df_item;
-	struct config_group *stats_cg;
-	int i;
-
-	stats_cg = &acl->se_node_acl.acl_fabric_stat_group;
-	for (i = 0; stats_cg->default_groups[i]; i++) {
-		df_item = &stats_cg->default_groups[i]->cg_item;
-		stats_cg->default_groups[i] = NULL;
-		config_item_put(df_item);
-	}
-	kfree(stats_cg->default_groups);
+
+	configfs_remove_default_groups(&acl->se_node_acl.acl_fabric_stat_group);
 }
 
 /* End items for lio_target_acl_cit */
@@ -1260,42 +1241,37 @@ static struct se_wwn *lio_target_call_coreaddtiqn(
 	struct config_group *group,
 	const char *name)
 {
-	struct config_group *stats_cg;
 	struct iscsi_tiqn *tiqn;
 
 	tiqn = iscsit_add_tiqn((unsigned char *)name);
 	if (IS_ERR(tiqn))
 		return ERR_CAST(tiqn);
-	/*
-	 * Setup struct iscsi_wwn_stat_grps for se_wwn->fabric_stat_group.
-	 */
-	stats_cg = &tiqn->tiqn_wwn.fabric_stat_group;
-
-	stats_cg->default_groups = kmalloc(sizeof(struct config_group *) * 6,
-				GFP_KERNEL);
-	if (!stats_cg->default_groups) {
-		pr_err("Unable to allocate memory for"
-				" stats_cg->default_groups\n");
-		iscsit_del_tiqn(tiqn);
-		return ERR_PTR(-ENOMEM);
-	}
 
-	stats_cg->default_groups[0] = &tiqn->tiqn_stat_grps.iscsi_instance_group;
-	stats_cg->default_groups[1] = &tiqn->tiqn_stat_grps.iscsi_sess_err_group;
-	stats_cg->default_groups[2] = &tiqn->tiqn_stat_grps.iscsi_tgt_attr_group;
-	stats_cg->default_groups[3] = &tiqn->tiqn_stat_grps.iscsi_login_stats_group;
-	stats_cg->default_groups[4] = &tiqn->tiqn_stat_grps.iscsi_logout_stats_group;
-	stats_cg->default_groups[5] = NULL;
 	config_group_init_type_name(&tiqn->tiqn_stat_grps.iscsi_instance_group,
 			"iscsi_instance", &iscsi_stat_instance_cit);
+	configfs_add_default_group(&tiqn->tiqn_stat_grps.iscsi_instance_group,
+			&tiqn->tiqn_wwn.fabric_stat_group);
+
 	config_group_init_type_name(&tiqn->tiqn_stat_grps.iscsi_sess_err_group,
 			"iscsi_sess_err", &iscsi_stat_sess_err_cit);
+	configfs_add_default_group(&tiqn->tiqn_stat_grps.iscsi_sess_err_group,
+			&tiqn->tiqn_wwn.fabric_stat_group);
+
 	config_group_init_type_name(&tiqn->tiqn_stat_grps.iscsi_tgt_attr_group,
 			"iscsi_tgt_attr", &iscsi_stat_tgt_attr_cit);
+	configfs_add_default_group(&tiqn->tiqn_stat_grps.iscsi_tgt_attr_group,
+			&tiqn->tiqn_wwn.fabric_stat_group);
+
 	config_group_init_type_name(&tiqn->tiqn_stat_grps.iscsi_login_stats_group,
 			"iscsi_login_stats", &iscsi_stat_login_cit);
+	configfs_add_default_group(&tiqn->tiqn_stat_grps.iscsi_login_stats_group,
+			&tiqn->tiqn_wwn.fabric_stat_group);
+
 	config_group_init_type_name(&tiqn->tiqn_stat_grps.iscsi_logout_stats_group,
 			"iscsi_logout_stats", &iscsi_stat_logout_cit);
+	configfs_add_default_group(&tiqn->tiqn_stat_grps.iscsi_logout_stats_group,
+			&tiqn->tiqn_wwn.fabric_stat_group);
+
 
 	pr_debug("LIO_Target_ConfigFS: REGISTER -> %s\n", tiqn->tiqn);
 	pr_debug("LIO_Target_ConfigFS: REGISTER -> Allocated Node:"
@@ -1307,17 +1283,8 @@ static void lio_target_call_coredeltiqn(
 	struct se_wwn *wwn)
 {
 	struct iscsi_tiqn *tiqn = container_of(wwn, struct iscsi_tiqn, tiqn_wwn);
-	struct config_item *df_item;
-	struct config_group *stats_cg;
-	int i;
-
-	stats_cg = &tiqn->tiqn_wwn.fabric_stat_group;
-	for (i = 0; stats_cg->default_groups[i]; i++) {
-		df_item = &stats_cg->default_groups[i]->cg_item;
-		stats_cg->default_groups[i] = NULL;
-		config_item_put(df_item);
-	}
-	kfree(stats_cg->default_groups);
+
+	configfs_remove_default_groups(&tiqn->tiqn_wwn.fabric_stat_group);
 
 	pr_debug("LIO_Target_ConfigFS: DEREGISTER -> %s\n",
 			tiqn->tiqn);
diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c
index 713c63d9681b..d498533f09ee 100644
--- a/drivers/target/target_core_configfs.c
+++ b/drivers/target/target_core_configfs.c
@@ -194,13 +194,11 @@ static struct config_group *target_core_register_fabric(
 	pr_debug("Target_Core_ConfigFS: REGISTER tfc_wwn_cit -> %p\n",
 			&tf->tf_wwn_cit);
 
-	tf->tf_group.default_groups = tf->tf_default_groups;
-	tf->tf_group.default_groups[0] = &tf->tf_disc_group;
-	tf->tf_group.default_groups[1] = NULL;
-
 	config_group_init_type_name(&tf->tf_group, name, &tf->tf_wwn_cit);
+
 	config_group_init_type_name(&tf->tf_disc_group, "discovery_auth",
 			&tf->tf_discovery_cit);
+	configfs_add_default_group(&tf->tf_disc_group, &tf->tf_group);
 
 	pr_debug("Target_Core_ConfigFS: REGISTER -> Allocated Fabric:"
 			" %s\n", tf->tf_group.cg_item.ci_name);
@@ -216,9 +214,6 @@ static void target_core_deregister_fabric(
 {
 	struct target_fabric_configfs *tf = container_of(
 		to_config_group(item), struct target_fabric_configfs, tf_group);
-	struct config_group *tf_group;
-	struct config_item *df_item;
-	int i;
 
 	pr_debug("Target_Core_ConfigFS: DEREGISTER -> Looking up %s in"
 		" tf list\n", config_item_name(item));
@@ -230,12 +225,7 @@ static void target_core_deregister_fabric(
 	pr_debug("Target_Core_ConfigFS: DEREGISTER -> Releasing ci"
 			" %s\n", config_item_name(item));
 
-	tf_group = &tf->tf_group;
-	for (i = 0; tf_group->default_groups[i]; i++) {
-		df_item = &tf_group->default_groups[i]->cg_item;
-		tf_group->default_groups[i] = NULL;
-		config_item_put(df_item);
-	}
+	configfs_remove_default_groups(&tf->tf_group);
 	config_item_put(item);
 }
 
@@ -2151,7 +2141,6 @@ static void target_core_dev_release(struct config_item *item)
 	struct se_device *dev =
 		container_of(dev_cg, struct se_device, dev_group);
 
-	kfree(dev_cg->default_groups);
 	target_free_device(dev);
 }
 
@@ -2819,8 +2808,6 @@ static struct config_group *target_core_make_subdev(
 	struct se_hba *hba = item_to_hba(hba_ci);
 	struct target_backend *tb = hba->backend;
 	struct se_device *dev;
-	struct config_group *dev_cg = NULL, *tg_pt_gp_cg = NULL;
-	struct config_group *dev_stat_grp = NULL;
 	int errno = -ENOMEM, ret;
 
 	ret = mutex_lock_interruptible(&hba->hba_access_mutex);
@@ -2831,73 +2818,52 @@ static struct config_group *target_core_make_subdev(
 	if (!dev)
 		goto out_unlock;
 
-	dev_cg = &dev->dev_group;
-
-	dev_cg->default_groups = kmalloc(sizeof(struct config_group *) * 6,
-			GFP_KERNEL);
-	if (!dev_cg->default_groups)
-		goto out_free_device;
+	config_group_init_type_name(&dev->dev_group, name, &tb->tb_dev_cit);
 
-	config_group_init_type_name(dev_cg, name, &tb->tb_dev_cit);
 	config_group_init_type_name(&dev->dev_attrib.da_group, "attrib",
 			&tb->tb_dev_attrib_cit);
+	configfs_add_default_group(&dev->dev_attrib.da_group, &dev->dev_group);
+
 	config_group_init_type_name(&dev->dev_pr_group, "pr",
 			&tb->tb_dev_pr_cit);
+	configfs_add_default_group(&dev->dev_pr_group, &dev->dev_group);
+
 	config_group_init_type_name(&dev->t10_wwn.t10_wwn_group, "wwn",
 			&tb->tb_dev_wwn_cit);
+	configfs_add_default_group(&dev->t10_wwn.t10_wwn_group,
+			&dev->dev_group);
+
 	config_group_init_type_name(&dev->t10_alua.alua_tg_pt_gps_group,
 			"alua", &tb->tb_dev_alua_tg_pt_gps_cit);
+	configfs_add_default_group(&dev->t10_alua.alua_tg_pt_gps_group,
+			&dev->dev_group);
+
 	config_group_init_type_name(&dev->dev_stat_grps.stat_group,
 			"statistics", &tb->tb_dev_stat_cit);
+	configfs_add_default_group(&dev->dev_stat_grps.stat_group,
+			&dev->dev_group);
 
-	dev_cg->default_groups[0] = &dev->dev_attrib.da_group;
-	dev_cg->default_groups[1] = &dev->dev_pr_group;
-	dev_cg->default_groups[2] = &dev->t10_wwn.t10_wwn_group;
-	dev_cg->default_groups[3] = &dev->t10_alua.alua_tg_pt_gps_group;
-	dev_cg->default_groups[4] = &dev->dev_stat_grps.stat_group;
-	dev_cg->default_groups[5] = NULL;
 	/*
 	 * Add core/$HBA/$DEV/alua/default_tg_pt_gp
 	 */
 	tg_pt_gp = core_alua_allocate_tg_pt_gp(dev, "default_tg_pt_gp", 1);
 	if (!tg_pt_gp)
-		goto out_free_dev_cg_default_groups;
+		goto out_free_device;
 	dev->t10_alua.default_tg_pt_gp = tg_pt_gp;
 
-	tg_pt_gp_cg = &dev->t10_alua.alua_tg_pt_gps_group;
-	tg_pt_gp_cg->default_groups = kmalloc(sizeof(struct config_group *) * 2,
-				GFP_KERNEL);
-	if (!tg_pt_gp_cg->default_groups) {
-		pr_err("Unable to allocate tg_pt_gp_cg->"
-				"default_groups\n");
-		goto out_free_tg_pt_gp;
-	}
-
 	config_group_init_type_name(&tg_pt_gp->tg_pt_gp_group,
 			"default_tg_pt_gp", &target_core_alua_tg_pt_gp_cit);
-	tg_pt_gp_cg->default_groups[0] = &tg_pt_gp->tg_pt_gp_group;
-	tg_pt_gp_cg->default_groups[1] = NULL;
+	configfs_add_default_group(&tg_pt_gp->tg_pt_gp_group,
+			&dev->t10_alua.alua_tg_pt_gps_group);
+
 	/*
 	 * Add core/$HBA/$DEV/statistics/ default groups
 	 */
-	dev_stat_grp = &dev->dev_stat_grps.stat_group;
-	dev_stat_grp->default_groups = kmalloc(sizeof(struct config_group *) * 4,
-				GFP_KERNEL);
-	if (!dev_stat_grp->default_groups) {
-		pr_err("Unable to allocate dev_stat_grp->default_groups\n");
-		goto out_free_tg_pt_gp_cg_default_groups;
-	}
 	target_stat_setup_dev_default_groups(dev);
 
 	mutex_unlock(&hba->hba_access_mutex);
-	return dev_cg;
+	return &dev->dev_group;
 
-out_free_tg_pt_gp_cg_default_groups:
-	kfree(tg_pt_gp_cg->default_groups);
-out_free_tg_pt_gp:
-	core_alua_free_tg_pt_gp(tg_pt_gp);
-out_free_dev_cg_default_groups:
-	kfree(dev_cg->default_groups);
 out_free_device:
 	target_free_device(dev);
 out_unlock:
@@ -2913,40 +2879,22 @@ static void target_core_drop_subdev(
 	struct se_device *dev =
 		container_of(dev_cg, struct se_device, dev_group);
 	struct se_hba *hba;
-	struct config_item *df_item;
-	struct config_group *tg_pt_gp_cg, *dev_stat_grp;
-	int i;
 
 	hba = item_to_hba(&dev->se_hba->hba_group.cg_item);
 
 	mutex_lock(&hba->hba_access_mutex);
 
-	dev_stat_grp = &dev->dev_stat_grps.stat_group;
-	for (i = 0; dev_stat_grp->default_groups[i]; i++) {
-		df_item = &dev_stat_grp->default_groups[i]->cg_item;
-		dev_stat_grp->default_groups[i] = NULL;
-		config_item_put(df_item);
-	}
-	kfree(dev_stat_grp->default_groups);
+	configfs_remove_default_groups(&dev->dev_stat_grps.stat_group);
+	configfs_remove_default_groups(&dev->t10_alua.alua_tg_pt_gps_group);
 
-	tg_pt_gp_cg = &dev->t10_alua.alua_tg_pt_gps_group;
-	for (i = 0; tg_pt_gp_cg->default_groups[i]; i++) {
-		df_item = &tg_pt_gp_cg->default_groups[i]->cg_item;
-		tg_pt_gp_cg->default_groups[i] = NULL;
-		config_item_put(df_item);
-	}
-	kfree(tg_pt_gp_cg->default_groups);
 	/*
 	 * core_alua_free_tg_pt_gp() is called from ->default_tg_pt_gp
 	 * directly from target_core_alua_tg_pt_gp_release().
 	 */
 	dev->t10_alua.default_tg_pt_gp = NULL;
 
-	for (i = 0; dev_cg->default_groups[i]; i++) {
-		df_item = &dev_cg->default_groups[i]->cg_item;
-		dev_cg->default_groups[i] = NULL;
-		config_item_put(df_item);
-	}
+	configfs_remove_default_groups(dev_cg);
+
 	/*
 	 * se_dev is released from target_core_dev_item_ops->release()
 	 */
@@ -3141,8 +3089,6 @@ void target_setup_backend_cits(struct target_backend *tb)
 
 static int __init target_core_init_configfs(void)
 {
-	struct config_group *target_cg, *hba_cg = NULL, *alua_cg = NULL;
-	struct config_group *lu_gp_cg = NULL;
 	struct configfs_subsystem *subsys = &target_core_fabrics;
 	struct t10_alua_lu_gp *lu_gp;
 	int ret;
@@ -3161,51 +3107,24 @@ static int __init target_core_init_configfs(void)
 	 * Create $CONFIGFS/target/core default group for HBA <-> Storage Object
 	 * and ALUA Logical Unit Group and Target Port Group infrastructure.
 	 */
-	target_cg = &subsys->su_group;
-	target_cg->default_groups = kmalloc(sizeof(struct config_group *) * 2,
-				GFP_KERNEL);
-	if (!target_cg->default_groups) {
-		pr_err("Unable to allocate target_cg->default_groups\n");
-		ret = -ENOMEM;
-		goto out_global;
-	}
+	config_group_init_type_name(&target_core_hbagroup, "core",
+			&target_core_cit);
+	configfs_add_default_group(&target_core_hbagroup, &subsys->su_group);
 
-	config_group_init_type_name(&target_core_hbagroup,
-			"core", &target_core_cit);
-	target_cg->default_groups[0] = &target_core_hbagroup;
-	target_cg->default_groups[1] = NULL;
 	/*
 	 * Create ALUA infrastructure under /sys/kernel/config/target/core/alua/
 	 */
-	hba_cg = &target_core_hbagroup;
-	hba_cg->default_groups = kmalloc(sizeof(struct config_group *) * 2,
-				GFP_KERNEL);
-	if (!hba_cg->default_groups) {
-		pr_err("Unable to allocate hba_cg->default_groups\n");
-		ret = -ENOMEM;
-		goto out_global;
-	}
-	config_group_init_type_name(&alua_group,
-			"alua", &target_core_alua_cit);
-	hba_cg->default_groups[0] = &alua_group;
-	hba_cg->default_groups[1] = NULL;
+	config_group_init_type_name(&alua_group, "alua", &target_core_alua_cit);
+	configfs_add_default_group(&alua_group, &target_core_hbagroup);
+
 	/*
 	 * Add ALUA Logical Unit Group and Target Port Group ConfigFS
 	 * groups under /sys/kernel/config/target/core/alua/
 	 */
-	alua_cg = &alua_group;
-	alua_cg->default_groups = kmalloc(sizeof(struct config_group *) * 2,
-			GFP_KERNEL);
-	if (!alua_cg->default_groups) {
-		pr_err("Unable to allocate alua_cg->default_groups\n");
-		ret = -ENOMEM;
-		goto out_global;
-	}
+	config_group_init_type_name(&alua_lu_gps_group, "lu_gps",
+			&target_core_alua_lu_gps_cit);
+	configfs_add_default_group(&alua_lu_gps_group, &alua_group);
 
-	config_group_init_type_name(&alua_lu_gps_group,
-			"lu_gps", &target_core_alua_lu_gps_cit);
-	alua_cg->default_groups[0] = &alua_lu_gps_group;
-	alua_cg->default_groups[1] = NULL;
 	/*
 	 * Add core/alua/lu_gps/default_lu_gp
 	 */
@@ -3215,20 +3134,12 @@ static int __init target_core_init_configfs(void)
 		goto out_global;
 	}
 
-	lu_gp_cg = &alua_lu_gps_group;
-	lu_gp_cg->default_groups = kmalloc(sizeof(struct config_group *) * 2,
-			GFP_KERNEL);
-	if (!lu_gp_cg->default_groups) {
-		pr_err("Unable to allocate lu_gp_cg->default_groups\n");
-		ret = -ENOMEM;
-		goto out_global;
-	}
-
 	config_group_init_type_name(&lu_gp->lu_gp_group, "default_lu_gp",
 				&target_core_alua_lu_gp_cit);
-	lu_gp_cg->default_groups[0] = &lu_gp->lu_gp_group;
-	lu_gp_cg->default_groups[1] = NULL;
+	configfs_add_default_group(&lu_gp->lu_gp_group, &alua_lu_gps_group);
+
 	default_lu_gp = lu_gp;
+
 	/*
 	 * Register the target_core_mod subsystem with configfs.
 	 */
@@ -3267,55 +3178,21 @@ out_global:
 		core_alua_free_lu_gp(default_lu_gp);
 		default_lu_gp = NULL;
 	}
-	if (lu_gp_cg)
-		kfree(lu_gp_cg->default_groups);
-	if (alua_cg)
-		kfree(alua_cg->default_groups);
-	if (hba_cg)
-		kfree(hba_cg->default_groups);
-	kfree(target_cg->default_groups);
 	release_se_kmem_caches();
 	return ret;
 }
 
 static void __exit target_core_exit_configfs(void)
 {
-	struct config_group *hba_cg, *alua_cg, *lu_gp_cg;
-	struct config_item *item;
-	int i;
+	configfs_remove_default_groups(&alua_lu_gps_group);
+	configfs_remove_default_groups(&alua_group);
+	configfs_remove_default_groups(&target_core_hbagroup);
 
-	lu_gp_cg = &alua_lu_gps_group;
-	for (i = 0; lu_gp_cg->default_groups[i]; i++) {
-		item = &lu_gp_cg->default_groups[i]->cg_item;
-		lu_gp_cg->default_groups[i] = NULL;
-		config_item_put(item);
-	}
-	kfree(lu_gp_cg->default_groups);
-	lu_gp_cg->default_groups = NULL;
-
-	alua_cg = &alua_group;
-	for (i = 0; alua_cg->default_groups[i]; i++) {
-		item = &alua_cg->default_groups[i]->cg_item;
-		alua_cg->default_groups[i] = NULL;
-		config_item_put(item);
-	}
-	kfree(alua_cg->default_groups);
-	alua_cg->default_groups = NULL;
-
-	hba_cg = &target_core_hbagroup;
-	for (i = 0; hba_cg->default_groups[i]; i++) {
-		item = &hba_cg->default_groups[i]->cg_item;
-		hba_cg->default_groups[i] = NULL;
-		config_item_put(item);
-	}
-	kfree(hba_cg->default_groups);
-	hba_cg->default_groups = NULL;
 	/*
 	 * We expect subsys->su_group.default_groups to be released
 	 * by configfs subsystem provider logic..
 	 */
 	configfs_unregister_subsystem(&target_core_fabrics);
-	kfree(target_core_fabrics.su_group.default_groups);
 
 	core_alua_free_lu_gp(default_lu_gp);
 	default_lu_gp = NULL;
diff --git a/drivers/target/target_core_fabric_configfs.c b/drivers/target/target_core_fabric_configfs.c
index f916d18ccb48..8caef31da415 100644
--- a/drivers/target/target_core_fabric_configfs.c
+++ b/drivers/target/target_core_fabric_configfs.c
@@ -273,18 +273,10 @@ static struct config_group *target_fabric_make_mappedlun(
 	struct se_portal_group *se_tpg = se_nacl->se_tpg;
 	struct target_fabric_configfs *tf = se_tpg->se_tpg_wwn->wwn_tf;
 	struct se_lun_acl *lacl = NULL;
-	struct config_item *acl_ci;
-	struct config_group *lacl_cg = NULL, *ml_stat_grp = NULL;
 	char *buf;
 	unsigned long long mapped_lun;
 	int ret = 0;
 
-	acl_ci = &group->cg_item;
-	if (!acl_ci) {
-		pr_err("Unable to locatel acl_ci\n");
-		return NULL;
-	}
-
 	buf = kzalloc(strlen(name) + 1, GFP_KERNEL);
 	if (!buf) {
 		pr_err("Unable to allocate memory for name buf\n");
@@ -315,37 +307,19 @@ static struct config_group *target_fabric_make_mappedlun(
 		goto out;
 	}
 
-	lacl_cg = &lacl->se_lun_group;
-	lacl_cg->default_groups = kmalloc(sizeof(struct config_group *) * 2,
-				GFP_KERNEL);
-	if (!lacl_cg->default_groups) {
-		pr_err("Unable to allocate lacl_cg->default_groups\n");
-		ret = -ENOMEM;
-		goto out;
-	}
-
 	config_group_init_type_name(&lacl->se_lun_group, name,
 			&tf->tf_tpg_mappedlun_cit);
+
 	config_group_init_type_name(&lacl->ml_stat_grps.stat_group,
 			"statistics", &tf->tf_tpg_mappedlun_stat_cit);
-	lacl_cg->default_groups[0] = &lacl->ml_stat_grps.stat_group;
-	lacl_cg->default_groups[1] = NULL;
-
-	ml_stat_grp = &lacl->ml_stat_grps.stat_group;
-	ml_stat_grp->default_groups = kmalloc(sizeof(struct config_group *) * 3,
-				GFP_KERNEL);
-	if (!ml_stat_grp->default_groups) {
-		pr_err("Unable to allocate ml_stat_grp->default_groups\n");
-		ret = -ENOMEM;
-		goto out;
-	}
+	configfs_add_default_group(&lacl->ml_stat_grps.stat_group,
+			&lacl->se_lun_group);
+
 	target_stat_setup_mappedlun_default_groups(lacl);
 
 	kfree(buf);
 	return &lacl->se_lun_group;
 out:
-	if (lacl_cg)
-		kfree(lacl_cg->default_groups);
 	kfree(lacl);
 	kfree(buf);
 	return ERR_PTR(ret);
@@ -357,25 +331,9 @@ static void target_fabric_drop_mappedlun(
 {
 	struct se_lun_acl *lacl = container_of(to_config_group(item),
 			struct se_lun_acl, se_lun_group);
-	struct config_item *df_item;
-	struct config_group *lacl_cg = NULL, *ml_stat_grp = NULL;
-	int i;
-
-	ml_stat_grp = &lacl->ml_stat_grps.stat_group;
-	for (i = 0; ml_stat_grp->default_groups[i]; i++) {
-		df_item = &ml_stat_grp->default_groups[i]->cg_item;
-		ml_stat_grp->default_groups[i] = NULL;
-		config_item_put(df_item);
-	}
-	kfree(ml_stat_grp->default_groups);
 
-	lacl_cg = &lacl->se_lun_group;
-	for (i = 0; lacl_cg->default_groups[i]; i++) {
-		df_item = &lacl_cg->default_groups[i]->cg_item;
-		lacl_cg->default_groups[i] = NULL;
-		config_item_put(df_item);
-	}
-	kfree(lacl_cg->default_groups);
+	configfs_remove_default_groups(&lacl->ml_stat_grps.stat_group);
+	configfs_remove_default_groups(&lacl->se_lun_group);
 
 	config_item_put(item);
 }
@@ -424,7 +382,6 @@ static struct config_group *target_fabric_make_nodeacl(
 			struct se_portal_group, tpg_acl_group);
 	struct target_fabric_configfs *tf = se_tpg->se_tpg_wwn->wwn_tf;
 	struct se_node_acl *se_nacl;
-	struct config_group *nacl_cg;
 
 	se_nacl = core_tpg_add_initiator_node_acl(se_tpg, name);
 	if (IS_ERR(se_nacl))
@@ -438,24 +395,28 @@ static struct config_group *target_fabric_make_nodeacl(
 		}
 	}
 
-	nacl_cg = &se_nacl->acl_group;
-	nacl_cg->default_groups = se_nacl->acl_default_groups;
-	nacl_cg->default_groups[0] = &se_nacl->acl_attrib_group;
-	nacl_cg->default_groups[1] = &se_nacl->acl_auth_group;
-	nacl_cg->default_groups[2] = &se_nacl->acl_param_group;
-	nacl_cg->default_groups[3] = &se_nacl->acl_fabric_stat_group;
-	nacl_cg->default_groups[4] = NULL;
-
 	config_group_init_type_name(&se_nacl->acl_group, name,
 			&tf->tf_tpg_nacl_base_cit);
+
 	config_group_init_type_name(&se_nacl->acl_attrib_group, "attrib",
 			&tf->tf_tpg_nacl_attrib_cit);
+	configfs_add_default_group(&se_nacl->acl_attrib_group,
+			&se_nacl->acl_group);
+
 	config_group_init_type_name(&se_nacl->acl_auth_group, "auth",
 			&tf->tf_tpg_nacl_auth_cit);
+	configfs_add_default_group(&se_nacl->acl_auth_group,
+			&se_nacl->acl_group);
+
 	config_group_init_type_name(&se_nacl->acl_param_group, "param",
 			&tf->tf_tpg_nacl_param_cit);
+	configfs_add_default_group(&se_nacl->acl_param_group,
+			&se_nacl->acl_group);
+
 	config_group_init_type_name(&se_nacl->acl_fabric_stat_group,
 			"fabric_statistics", &tf->tf_tpg_nacl_stat_cit);
+	configfs_add_default_group(&se_nacl->acl_fabric_stat_group,
+			&se_nacl->acl_group);
 
 	return &se_nacl->acl_group;
 }
@@ -466,16 +427,9 @@ static void target_fabric_drop_nodeacl(
 {
 	struct se_node_acl *se_nacl = container_of(to_config_group(item),
 			struct se_node_acl, acl_group);
-	struct config_item *df_item;
-	struct config_group *nacl_cg;
-	int i;
-
-	nacl_cg = &se_nacl->acl_group;
-	for (i = 0; nacl_cg->default_groups[i]; i++) {
-		df_item = &nacl_cg->default_groups[i]->cg_item;
-		nacl_cg->default_groups[i] = NULL;
-		config_item_put(df_item);
-	}
+
+	configfs_remove_default_groups(&se_nacl->acl_group);
+
 	/*
 	 * struct se_node_acl free is done in target_fabric_nacl_base_release()
 	 */
@@ -795,7 +749,6 @@ static struct config_group *target_fabric_make_lun(
 	struct se_portal_group *se_tpg = container_of(group,
 			struct se_portal_group, tpg_lun_group);
 	struct target_fabric_configfs *tf = se_tpg->se_tpg_wwn->wwn_tf;
-	struct config_group *lun_cg = NULL, *port_stat_grp = NULL;
 	unsigned long long unpacked_lun;
 	int errno;
 
@@ -812,31 +765,14 @@ static struct config_group *target_fabric_make_lun(
 	if (IS_ERR(lun))
 		return ERR_CAST(lun);
 
-	lun_cg = &lun->lun_group;
-	lun_cg->default_groups = kmalloc(sizeof(struct config_group *) * 2,
-				GFP_KERNEL);
-	if (!lun_cg->default_groups) {
-		pr_err("Unable to allocate lun_cg->default_groups\n");
-		kfree(lun);
-		return ERR_PTR(-ENOMEM);
-	}
-
 	config_group_init_type_name(&lun->lun_group, name,
 			&tf->tf_tpg_port_cit);
+
 	config_group_init_type_name(&lun->port_stat_grps.stat_group,
 			"statistics", &tf->tf_tpg_port_stat_cit);
-	lun_cg->default_groups[0] = &lun->port_stat_grps.stat_group;
-	lun_cg->default_groups[1] = NULL;
-
-	port_stat_grp = &lun->port_stat_grps.stat_group;
-	port_stat_grp->default_groups =  kzalloc(sizeof(struct config_group *) * 4,
-				GFP_KERNEL);
-	if (!port_stat_grp->default_groups) {
-		pr_err("Unable to allocate port_stat_grp->default_groups\n");
-		kfree(lun_cg->default_groups);
-		kfree(lun);
-		return ERR_PTR(-ENOMEM);
-	}
+	configfs_add_default_group(&lun->port_stat_grps.stat_group,
+			&lun->lun_group);
+
 	target_stat_setup_port_default_groups(lun);
 
 	return &lun->lun_group;
@@ -848,25 +784,9 @@ static void target_fabric_drop_lun(
 {
 	struct se_lun *lun = container_of(to_config_group(item),
 				struct se_lun, lun_group);
-	struct config_item *df_item;
-	struct config_group *lun_cg, *port_stat_grp;
-	int i;
-
-	port_stat_grp = &lun->port_stat_grps.stat_group;
-	for (i = 0; port_stat_grp->default_groups[i]; i++) {
-		df_item = &port_stat_grp->default_groups[i]->cg_item;
-		port_stat_grp->default_groups[i] = NULL;
-		config_item_put(df_item);
-	}
-	kfree(port_stat_grp->default_groups);
 
-	lun_cg = &lun->lun_group;
-	for (i = 0; lun_cg->default_groups[i]; i++) {
-		df_item = &lun_cg->default_groups[i]->cg_item;
-		lun_cg->default_groups[i] = NULL;
-		config_item_put(df_item);
-	}
-	kfree(lun_cg->default_groups);
+	configfs_remove_default_groups(&lun->port_stat_grps.stat_group);
+	configfs_remove_default_groups(&lun->lun_group);
 
 	config_item_put(item);
 }
@@ -922,32 +842,39 @@ static struct config_group *target_fabric_make_tpg(
 	se_tpg = tf->tf_ops->fabric_make_tpg(wwn, group, name);
 	if (!se_tpg || IS_ERR(se_tpg))
 		return ERR_PTR(-EINVAL);
-	/*
-	 * Setup default groups from pre-allocated se_tpg->tpg_default_groups
-	 */
-	se_tpg->tpg_group.default_groups = se_tpg->tpg_default_groups;
-	se_tpg->tpg_group.default_groups[0] = &se_tpg->tpg_lun_group;
-	se_tpg->tpg_group.default_groups[1] = &se_tpg->tpg_np_group;
-	se_tpg->tpg_group.default_groups[2] = &se_tpg->tpg_acl_group;
-	se_tpg->tpg_group.default_groups[3] = &se_tpg->tpg_attrib_group;
-	se_tpg->tpg_group.default_groups[4] = &se_tpg->tpg_auth_group;
-	se_tpg->tpg_group.default_groups[5] = &se_tpg->tpg_param_group;
-	se_tpg->tpg_group.default_groups[6] = NULL;
 
 	config_group_init_type_name(&se_tpg->tpg_group, name,
 			&tf->tf_tpg_base_cit);
+
 	config_group_init_type_name(&se_tpg->tpg_lun_group, "lun",
 			&tf->tf_tpg_lun_cit);
+	configfs_add_default_group(&se_tpg->tpg_lun_group,
+			&se_tpg->tpg_group);
+
 	config_group_init_type_name(&se_tpg->tpg_np_group, "np",
 			&tf->tf_tpg_np_cit);
+	configfs_add_default_group(&se_tpg->tpg_np_group,
+			&se_tpg->tpg_group);
+
 	config_group_init_type_name(&se_tpg->tpg_acl_group, "acls",
 			&tf->tf_tpg_nacl_cit);
+	configfs_add_default_group(&se_tpg->tpg_acl_group,
+			&se_tpg->tpg_group);
+
 	config_group_init_type_name(&se_tpg->tpg_attrib_group, "attrib",
 			&tf->tf_tpg_attrib_cit);
+	configfs_add_default_group(&se_tpg->tpg_attrib_group,
+			&se_tpg->tpg_group);
+
 	config_group_init_type_name(&se_tpg->tpg_auth_group, "auth",
 			&tf->tf_tpg_auth_cit);
+	configfs_add_default_group(&se_tpg->tpg_auth_group,
+			&se_tpg->tpg_group);
+
 	config_group_init_type_name(&se_tpg->tpg_param_group, "param",
 			&tf->tf_tpg_param_cit);
+	configfs_add_default_group(&se_tpg->tpg_param_group,
+			&se_tpg->tpg_group);
 
 	return &se_tpg->tpg_group;
 }
@@ -958,19 +885,8 @@ static void target_fabric_drop_tpg(
 {
 	struct se_portal_group *se_tpg = container_of(to_config_group(item),
 				struct se_portal_group, tpg_group);
-	struct config_group *tpg_cg = &se_tpg->tpg_group;
-	struct config_item *df_item;
-	int i;
-	/*
-	 * Release default groups, but do not release tpg_cg->default_groups
-	 * memory as it is statically allocated at se_tpg->tpg_default_groups.
-	 */
-	for (i = 0; tpg_cg->default_groups[i]; i++) {
-		df_item = &tpg_cg->default_groups[i]->cg_item;
-		tpg_cg->default_groups[i] = NULL;
-		config_item_put(df_item);
-	}
 
+	configfs_remove_default_groups(&se_tpg->tpg_group);
 	config_item_put(item);
 }
 
@@ -1026,16 +942,12 @@ static struct config_group *target_fabric_make_wwn(
 		return ERR_PTR(-EINVAL);
 
 	wwn->wwn_tf = tf;
-	/*
-	 * Setup default groups from pre-allocated wwn->wwn_default_groups
-	 */
-	wwn->wwn_group.default_groups = wwn->wwn_default_groups;
-	wwn->wwn_group.default_groups[0] = &wwn->fabric_stat_group;
-	wwn->wwn_group.default_groups[1] = NULL;
 
 	config_group_init_type_name(&wwn->wwn_group, name, &tf->tf_tpg_cit);
+
 	config_group_init_type_name(&wwn->fabric_stat_group, "fabric_statistics",
 			&tf->tf_wwn_fabric_stats_cit);
+	configfs_add_default_group(&wwn->fabric_stat_group, &wwn->wwn_group);
 
 	return &wwn->wwn_group;
 }
@@ -1046,16 +958,8 @@ static void target_fabric_drop_wwn(
 {
 	struct se_wwn *wwn = container_of(to_config_group(item),
 				struct se_wwn, wwn_group);
-	struct config_item *df_item;
-	struct config_group *cg = &wwn->wwn_group;
-	int i;
-
-	for (i = 0; cg->default_groups[i]; i++) {
-		df_item = &cg->default_groups[i]->cg_item;
-		cg->default_groups[i] = NULL;
-		config_item_put(df_item);
-	}
 
+	configfs_remove_default_groups(&wwn->wwn_group);
 	config_item_put(item);
 }
 
diff --git a/drivers/target/target_core_internal.h b/drivers/target/target_core_internal.h
index db4412fe6b8a..4a7cf499cdfa 100644
--- a/drivers/target/target_core_internal.h
+++ b/drivers/target/target_core_internal.h
@@ -22,7 +22,6 @@ struct target_fabric_configfs {
 	struct list_head	tf_list;
 	struct config_group	tf_group;
 	struct config_group	tf_disc_group;
-	struct config_group	*tf_default_groups[2];
 	const struct target_core_fabric_ops *tf_ops;
 
 	struct config_item_type tf_discovery_cit;
diff --git a/drivers/target/target_core_stat.c b/drivers/target/target_core_stat.c
index 81a6b3e07687..1a39033d2bff 100644
--- a/drivers/target/target_core_stat.c
+++ b/drivers/target/target_core_stat.c
@@ -407,19 +407,20 @@ static struct config_item_type target_stat_scsi_lu_cit = {
  */
 void target_stat_setup_dev_default_groups(struct se_device *dev)
 {
-	struct config_group *dev_stat_grp = &dev->dev_stat_grps.stat_group;
-
 	config_group_init_type_name(&dev->dev_stat_grps.scsi_dev_group,
 			"scsi_dev", &target_stat_scsi_dev_cit);
+	configfs_add_default_group(&dev->dev_stat_grps.scsi_dev_group,
+			&dev->dev_stat_grps.stat_group);
+
 	config_group_init_type_name(&dev->dev_stat_grps.scsi_tgt_dev_group,
 			"scsi_tgt_dev", &target_stat_scsi_tgt_dev_cit);
+	configfs_add_default_group(&dev->dev_stat_grps.scsi_tgt_dev_group,
+			&dev->dev_stat_grps.stat_group);
+
 	config_group_init_type_name(&dev->dev_stat_grps.scsi_lu_group,
 			"scsi_lu", &target_stat_scsi_lu_cit);
-
-	dev_stat_grp->default_groups[0] = &dev->dev_stat_grps.scsi_dev_group;
-	dev_stat_grp->default_groups[1] = &dev->dev_stat_grps.scsi_tgt_dev_group;
-	dev_stat_grp->default_groups[2] = &dev->dev_stat_grps.scsi_lu_group;
-	dev_stat_grp->default_groups[3] = NULL;
+	configfs_add_default_group(&dev->dev_stat_grps.scsi_lu_group,
+			&dev->dev_stat_grps.stat_group);
 }
 
 /*
@@ -818,19 +819,20 @@ static struct config_item_type target_stat_scsi_transport_cit = {
  */
 void target_stat_setup_port_default_groups(struct se_lun *lun)
 {
-	struct config_group *port_stat_grp = &lun->port_stat_grps.stat_group;
-
 	config_group_init_type_name(&lun->port_stat_grps.scsi_port_group,
 			"scsi_port", &target_stat_scsi_port_cit);
+	configfs_add_default_group(&lun->port_stat_grps.scsi_port_group,
+			&lun->port_stat_grps.stat_group);
+
 	config_group_init_type_name(&lun->port_stat_grps.scsi_tgt_port_group,
 			"scsi_tgt_port", &target_stat_scsi_tgt_port_cit);
+	configfs_add_default_group(&lun->port_stat_grps.scsi_tgt_port_group,
+			&lun->port_stat_grps.stat_group);
+
 	config_group_init_type_name(&lun->port_stat_grps.scsi_transport_group,
 			"scsi_transport", &target_stat_scsi_transport_cit);
-
-	port_stat_grp->default_groups[0] = &lun->port_stat_grps.scsi_port_group;
-	port_stat_grp->default_groups[1] = &lun->port_stat_grps.scsi_tgt_port_group;
-	port_stat_grp->default_groups[2] = &lun->port_stat_grps.scsi_transport_group;
-	port_stat_grp->default_groups[3] = NULL;
+	configfs_add_default_group(&lun->port_stat_grps.scsi_transport_group,
+			&lun->port_stat_grps.stat_group);
 }
 
 /*
@@ -1351,14 +1353,13 @@ static struct config_item_type target_stat_scsi_att_intr_port_cit = {
  */
 void target_stat_setup_mappedlun_default_groups(struct se_lun_acl *lacl)
 {
-	struct config_group *ml_stat_grp = &lacl->ml_stat_grps.stat_group;
-
 	config_group_init_type_name(&lacl->ml_stat_grps.scsi_auth_intr_group,
 			"scsi_auth_intr", &target_stat_scsi_auth_intr_cit);
+	configfs_add_default_group(&lacl->ml_stat_grps.scsi_auth_intr_group,
+			&lacl->ml_stat_grps.stat_group);
+
 	config_group_init_type_name(&lacl->ml_stat_grps.scsi_att_intr_port_group,
 			"scsi_att_intr_port", &target_stat_scsi_att_intr_port_cit);
-
-	ml_stat_grp->default_groups[0] = &lacl->ml_stat_grps.scsi_auth_intr_group;
-	ml_stat_grp->default_groups[1] = &lacl->ml_stat_grps.scsi_att_intr_port_group;
-	ml_stat_grp->default_groups[2] = NULL;
+	configfs_add_default_group(&lacl->ml_stat_grps.scsi_att_intr_port_group,
+			&lacl->ml_stat_grps.stat_group);
 }
diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c
index 590c44989e5e..2f8081f0f795 100644
--- a/drivers/usb/gadget/configfs.c
+++ b/drivers/usb/gadget/configfs.c
@@ -49,7 +49,6 @@ struct gadget_info {
 	struct config_group configs_group;
 	struct config_group strings_group;
 	struct config_group os_desc_group;
-	struct config_group *default_groups[5];
 
 	struct mutex lock;
 	struct usb_gadget_strings *gstrings[MAX_USB_STRING_LANGS + 1];
@@ -71,7 +70,6 @@ static inline struct gadget_info *to_gadget_info(struct config_item *item)
 struct config_usb_cfg {
 	struct config_group group;
 	struct config_group strings_group;
-	struct config_group *default_groups[2];
 	struct list_head string_list;
 	struct usb_configuration c;
 	struct list_head func_list;
@@ -666,13 +664,12 @@ static struct config_group *config_desc_make(
 	INIT_LIST_HEAD(&cfg->string_list);
 	INIT_LIST_HEAD(&cfg->func_list);
 
-	cfg->group.default_groups = cfg->default_groups;
-	cfg->default_groups[0] = &cfg->strings_group;
-
 	config_group_init_type_name(&cfg->group, name,
 				&gadget_config_type);
+
 	config_group_init_type_name(&cfg->strings_group, "strings",
 			&gadget_config_name_strings_type);
+	configfs_add_default_group(&cfg->strings_group, &cfg->group);
 
 	ret = usb_add_config_only(&gi->cdev, &cfg->c);
 	if (ret)
@@ -1149,15 +1146,11 @@ int usb_os_desc_prepare_interf_dir(struct config_group *parent,
 				   char **names,
 				   struct module *owner)
 {
-	struct config_group **f_default_groups, *os_desc_group,
-				**interface_groups;
+	struct config_group *os_desc_group;
 	struct config_item_type *os_desc_type, *interface_type;
 
 	vla_group(data_chunk);
-	vla_item(data_chunk, struct config_group *, f_default_groups, 2);
 	vla_item(data_chunk, struct config_group, os_desc_group, 1);
-	vla_item(data_chunk, struct config_group *, interface_groups,
-		 n_interf + 1);
 	vla_item(data_chunk, struct config_item_type, os_desc_type, 1);
 	vla_item(data_chunk, struct config_item_type, interface_type, 1);
 
@@ -1165,18 +1158,14 @@ int usb_os_desc_prepare_interf_dir(struct config_group *parent,
 	if (!vlabuf)
 		return -ENOMEM;
 
-	f_default_groups = vla_ptr(vlabuf, data_chunk, f_default_groups);
 	os_desc_group = vla_ptr(vlabuf, data_chunk, os_desc_group);
 	os_desc_type = vla_ptr(vlabuf, data_chunk, os_desc_type);
-	interface_groups = vla_ptr(vlabuf, data_chunk, interface_groups);
 	interface_type = vla_ptr(vlabuf, data_chunk, interface_type);
 
-	parent->default_groups = f_default_groups;
 	os_desc_type->ct_owner = owner;
 	config_group_init_type_name(os_desc_group, "os_desc", os_desc_type);
-	f_default_groups[0] = os_desc_group;
+	configfs_add_default_group(os_desc_group, parent);
 
-	os_desc_group->default_groups = interface_groups;
 	interface_type->ct_group_ops = &interf_grp_ops;
 	interface_type->ct_attrs = interf_grp_attrs;
 	interface_type->ct_owner = owner;
@@ -1189,7 +1178,7 @@ int usb_os_desc_prepare_interf_dir(struct config_group *parent,
 		config_group_init_type_name(&d->group, "", interface_type);
 		config_item_set_name(&d->group.cg_item, "interface.%s",
 				     names[n_interf]);
-		interface_groups[n_interf] = &d->group;
+		configfs_add_default_group(&d->group, os_desc_group);
 	}
 
 	return 0;
@@ -1423,20 +1412,23 @@ static struct config_group *gadgets_make(
 	if (!gi)
 		return ERR_PTR(-ENOMEM);
 
-	gi->group.default_groups = gi->default_groups;
-	gi->group.default_groups[0] = &gi->functions_group;
-	gi->group.default_groups[1] = &gi->configs_group;
-	gi->group.default_groups[2] = &gi->strings_group;
-	gi->group.default_groups[3] = &gi->os_desc_group;
+	config_group_init_type_name(&gi->group, name, &gadget_root_type);
 
 	config_group_init_type_name(&gi->functions_group, "functions",
 			&functions_type);
+	configfs_add_default_group(&gi->functions_group, &gi->group);
+
 	config_group_init_type_name(&gi->configs_group, "configs",
 			&config_desc_type);
+	configfs_add_default_group(&gi->configs_group, &gi->group);
+
 	config_group_init_type_name(&gi->strings_group, "strings",
 			&gadget_strings_strings_type);
+	configfs_add_default_group(&gi->strings_group, &gi->group);
+
 	config_group_init_type_name(&gi->os_desc_group, "os_desc",
 			&os_desc_type);
+	configfs_add_default_group(&gi->os_desc_group, &gi->group);
 
 	gi->composite.bind = configfs_do_nothing;
 	gi->composite.unbind = configfs_do_nothing;
@@ -1461,8 +1453,6 @@ static struct config_group *gadgets_make(
 	if (!gi->composite.gadget_driver.function)
 		goto err;
 
-	config_group_init_type_name(&gi->group, name,
-				&gadget_root_type);
 	return &gi->group;
 err:
 	kfree(gi);
diff --git a/drivers/usb/gadget/function/f_mass_storage.c b/drivers/usb/gadget/function/f_mass_storage.c
index 223ccf89d226..142bb7763f2a 100644
--- a/drivers/usb/gadget/function/f_mass_storage.c
+++ b/drivers/usb/gadget/function/f_mass_storage.c
@@ -3484,12 +3484,12 @@ static struct usb_function_instance *fsg_alloc_inst(void)
 
 	opts->lun0.lun = opts->common->luns[0];
 	opts->lun0.lun_id = 0;
-	config_group_init_type_name(&opts->lun0.group, "lun.0", &fsg_lun_type);
-	opts->default_groups[0] = &opts->lun0.group;
-	opts->func_inst.group.default_groups = opts->default_groups;
 
 	config_group_init_type_name(&opts->func_inst.group, "", &fsg_func_type);
 
+	config_group_init_type_name(&opts->lun0.group, "lun.0", &fsg_lun_type);
+	configfs_add_default_group(&opts->lun0.group, &opts->func_inst.group);
+
 	return &opts->func_inst;
 
 release_buffers:
diff --git a/drivers/usb/gadget/function/f_rndis.c b/drivers/usb/gadget/function/f_rndis.c
index e587767e374c..f577eec88f8c 100644
--- a/drivers/usb/gadget/function/f_rndis.c
+++ b/drivers/usb/gadget/function/f_rndis.c
@@ -889,7 +889,6 @@ static void rndis_free_inst(struct usb_function_instance *f)
 			free_netdev(opts->net);
 	}
 
-	kfree(opts->rndis_os_desc.group.default_groups); /* single VLA chunk */
 	kfree(opts);
 }
 
@@ -916,10 +915,10 @@ static struct usb_function_instance *rndis_alloc_inst(void)
 
 	descs[0] = &opts->rndis_os_desc;
 	names[0] = "rndis";
-	usb_os_desc_prepare_interf_dir(&opts->func_inst.group, 1, descs,
-				       names, THIS_MODULE);
 	config_group_init_type_name(&opts->func_inst.group, "",
 				    &rndis_func_type);
+	usb_os_desc_prepare_interf_dir(&opts->func_inst.group, 1, descs,
+				       names, THIS_MODULE);
 
 	return &opts->func_inst;
 }
diff --git a/drivers/usb/gadget/function/uvc_configfs.c b/drivers/usb/gadget/function/uvc_configfs.c
index ad8c9b05572d..66753ba7a42e 100644
--- a/drivers/usb/gadget/function/uvc_configfs.c
+++ b/drivers/usb/gadget/function/uvc_configfs.c
@@ -272,11 +272,6 @@ static struct config_item_type uvcg_default_processing_type = {
 
 /* struct uvcg_processing {}; */
 
-static struct config_group *uvcg_processing_default_groups[] = {
-	&uvcg_default_processing.group,
-	NULL,
-};
-
 /* control/processing */
 static struct uvcg_processing_grp {
 	struct config_group	group;
@@ -394,11 +389,6 @@ static struct config_item_type uvcg_default_camera_type = {
 
 /* struct uvcg_camera {}; */
 
-static struct config_group *uvcg_camera_default_groups[] = {
-	&uvcg_default_camera.group,
-	NULL,
-};
-
 /* control/terminal/camera */
 static struct uvcg_camera_grp {
 	struct config_group	group;
@@ -477,11 +467,6 @@ static struct config_item_type uvcg_default_output_type = {
 
 /* struct uvcg_output {}; */
 
-static struct config_group *uvcg_output_default_groups[] = {
-	&uvcg_default_output.group,
-	NULL,
-};
-
 /* control/terminal/output */
 static struct uvcg_output_grp {
 	struct config_group	group;
@@ -491,12 +476,6 @@ static struct config_item_type uvcg_output_grp_type = {
 	.ct_owner = THIS_MODULE,
 };
 
-static struct config_group *uvcg_terminal_default_groups[] = {
-	&uvcg_camera_grp.group,
-	&uvcg_output_grp.group,
-	NULL,
-};
-
 /* control/terminal */
 static struct uvcg_terminal_grp {
 	struct config_group	group;
@@ -619,12 +598,6 @@ static struct config_item_type uvcg_control_class_type = {
 	.ct_owner	= THIS_MODULE,
 };
 
-static struct config_group *uvcg_control_class_default_groups[] = {
-	&uvcg_control_class_fs.group,
-	&uvcg_control_class_ss.group,
-	NULL,
-};
-
 /* control/class */
 static struct uvcg_control_class_grp {
 	struct config_group	group;
@@ -634,14 +607,6 @@ static struct config_item_type uvcg_control_class_grp_type = {
 	.ct_owner = THIS_MODULE,
 };
 
-static struct config_group *uvcg_control_default_groups[] = {
-	&uvcg_control_header_grp.group,
-	&uvcg_processing_grp.group,
-	&uvcg_terminal_grp.group,
-	&uvcg_control_class_grp.group,
-	NULL,
-};
-
 /* control */
 static struct uvcg_control_grp {
 	struct config_group	group;
@@ -1780,11 +1745,6 @@ static struct config_item_type uvcg_default_color_matching_type = {
 
 /* struct uvcg_color_matching {}; */
 
-static struct config_group *uvcg_color_matching_default_groups[] = {
-	&uvcg_default_color_matching.group,
-	NULL,
-};
-
 /* streaming/color_matching */
 static struct uvcg_color_matching_grp {
 	struct config_group	group;
@@ -2145,13 +2105,6 @@ static struct config_item_type uvcg_streaming_class_type = {
 	.ct_owner	= THIS_MODULE,
 };
 
-static struct config_group *uvcg_streaming_class_default_groups[] = {
-	&uvcg_streaming_class_fs.group,
-	&uvcg_streaming_class_hs.group,
-	&uvcg_streaming_class_ss.group,
-	NULL,
-};
-
 /* streaming/class */
 static struct uvcg_streaming_class_grp {
 	struct config_group	group;
@@ -2161,15 +2114,6 @@ static struct config_item_type uvcg_streaming_class_grp_type = {
 	.ct_owner = THIS_MODULE,
 };
 
-static struct config_group *uvcg_streaming_default_groups[] = {
-	&uvcg_streaming_header_grp.group,
-	&uvcg_uncompressed_grp.group,
-	&uvcg_mjpeg_grp.group,
-	&uvcg_color_matching_grp.group,
-	&uvcg_streaming_class_grp.group,
-	NULL,
-};
-
 /* streaming */
 static struct uvcg_streaming_grp {
 	struct config_group	group;
@@ -2179,12 +2123,6 @@ static struct config_item_type uvcg_streaming_grp_type = {
 	.ct_owner = THIS_MODULE,
 };
 
-static struct config_group *uvcg_default_groups[] = {
-	&uvcg_control_grp.group,
-	&uvcg_streaming_grp.group,
-	NULL,
-};
-
 static inline struct f_uvc_opts *to_f_uvc_opts(struct config_item *item)
 {
 	return container_of(to_config_group(item), struct f_uvc_opts,
@@ -2273,59 +2211,64 @@ static struct config_item_type uvc_func_type = {
 	.ct_owner	= THIS_MODULE,
 };
 
-static inline void uvcg_init_group(struct config_group *g,
-				   struct config_group **default_groups,
-				   const char *name,
-				   struct config_item_type *type)
-{
-	g->default_groups = default_groups;
-	config_group_init_type_name(g, name, type);
-}
-
 int uvcg_attach_configfs(struct f_uvc_opts *opts)
 {
 	config_group_init_type_name(&uvcg_control_header_grp.group,
 				    "header",
 				    &uvcg_control_header_grp_type);
+
 	config_group_init_type_name(&uvcg_default_processing.group,
-				    "default",
-				    &uvcg_default_processing_type);
-	uvcg_init_group(&uvcg_processing_grp.group,
-			uvcg_processing_default_groups,
-			"processing",
-			&uvcg_processing_grp_type);
+			"default", &uvcg_default_processing_type);
+	config_group_init_type_name(&uvcg_processing_grp.group,
+			"processing", &uvcg_processing_grp_type);
+	configfs_add_default_group(&uvcg_default_processing.group,
+			&uvcg_processing_grp.group);
+
 	config_group_init_type_name(&uvcg_default_camera.group,
-				    "default",
-				    &uvcg_default_camera_type);
-	uvcg_init_group(&uvcg_camera_grp.group,
-			uvcg_camera_default_groups,
-			"camera",
-			&uvcg_camera_grp_type);
+			"default", &uvcg_default_camera_type);
+	config_group_init_type_name(&uvcg_camera_grp.group,
+			"camera", &uvcg_camera_grp_type);
+	configfs_add_default_group(&uvcg_default_camera.group,
+			&uvcg_camera_grp.group);
+
 	config_group_init_type_name(&uvcg_default_output.group,
-				    "default",
-				    &uvcg_default_output_type);
-	uvcg_init_group(&uvcg_output_grp.group,
-			uvcg_output_default_groups,
-			"output",
-			&uvcg_output_grp_type);
-	uvcg_init_group(&uvcg_terminal_grp.group,
-			uvcg_terminal_default_groups,
-			"terminal",
-			&uvcg_terminal_grp_type);
+			"default", &uvcg_default_output_type);
+	config_group_init_type_name(&uvcg_output_grp.group,
+			"output", &uvcg_output_grp_type);
+	configfs_add_default_group(&uvcg_default_output.group,
+			&uvcg_output_grp.group);
+
+	config_group_init_type_name(&uvcg_terminal_grp.group,
+			"terminal", &uvcg_terminal_grp_type);
+	configfs_add_default_group(&uvcg_camera_grp.group,
+			&uvcg_terminal_grp.group);
+	configfs_add_default_group(&uvcg_output_grp.group,
+			&uvcg_terminal_grp.group);
+
 	config_group_init_type_name(&uvcg_control_class_fs.group,
-				    "fs",
-				    &uvcg_control_class_type);
+			"fs", &uvcg_control_class_type);
 	config_group_init_type_name(&uvcg_control_class_ss.group,
-				    "ss",
-				    &uvcg_control_class_type);
-	uvcg_init_group(&uvcg_control_class_grp.group,
-			uvcg_control_class_default_groups,
+			"ss", &uvcg_control_class_type);
+	config_group_init_type_name(&uvcg_control_class_grp.group,
 			"class",
 			&uvcg_control_class_grp_type);
-	uvcg_init_group(&uvcg_control_grp.group,
-			uvcg_control_default_groups,
+	configfs_add_default_group(&uvcg_control_class_fs.group,
+			&uvcg_control_class_grp.group);
+	configfs_add_default_group(&uvcg_control_class_ss.group,
+			&uvcg_control_class_grp.group);
+
+	config_group_init_type_name(&uvcg_control_grp.group,
 			"control",
 			&uvcg_control_grp_type);
+	configfs_add_default_group(&uvcg_control_header_grp.group,
+			&uvcg_control_grp.group);
+	configfs_add_default_group(&uvcg_processing_grp.group,
+			&uvcg_control_grp.group);
+	configfs_add_default_group(&uvcg_terminal_grp.group,
+			&uvcg_control_grp.group);
+	configfs_add_default_group(&uvcg_control_class_grp.group,
+			&uvcg_control_grp.group);
+
 	config_group_init_type_name(&uvcg_streaming_header_grp.group,
 				    "header",
 				    &uvcg_streaming_header_grp_type);
@@ -2338,30 +2281,47 @@ int uvcg_attach_configfs(struct f_uvc_opts *opts)
 	config_group_init_type_name(&uvcg_default_color_matching.group,
 				    "default",
 				    &uvcg_default_color_matching_type);
-	uvcg_init_group(&uvcg_color_matching_grp.group,
-			uvcg_color_matching_default_groups,
+	config_group_init_type_name(&uvcg_color_matching_grp.group,
 			"color_matching",
 			&uvcg_color_matching_grp_type);
+	configfs_add_default_group(&uvcg_default_color_matching.group,
+			&uvcg_color_matching_grp.group);
+
 	config_group_init_type_name(&uvcg_streaming_class_fs.group,
-				    "fs",
-				    &uvcg_streaming_class_type);
+			"fs", &uvcg_streaming_class_type);
 	config_group_init_type_name(&uvcg_streaming_class_hs.group,
-				    "hs",
-				    &uvcg_streaming_class_type);
+			"hs", &uvcg_streaming_class_type);
 	config_group_init_type_name(&uvcg_streaming_class_ss.group,
-				    "ss",
-				    &uvcg_streaming_class_type);
-	uvcg_init_group(&uvcg_streaming_class_grp.group,
-			uvcg_streaming_class_default_groups,
-			"class",
-			&uvcg_streaming_class_grp_type);
-	uvcg_init_group(&uvcg_streaming_grp.group,
-			uvcg_streaming_default_groups,
-			"streaming",
-			&uvcg_streaming_grp_type);
-	uvcg_init_group(&opts->func_inst.group,
-			uvcg_default_groups,
+			"ss", &uvcg_streaming_class_type);
+	config_group_init_type_name(&uvcg_streaming_class_grp.group,
+			"class", &uvcg_streaming_class_grp_type);
+	configfs_add_default_group(&uvcg_streaming_class_fs.group,
+			&uvcg_streaming_class_grp.group);
+	configfs_add_default_group(&uvcg_streaming_class_hs.group,
+			&uvcg_streaming_class_grp.group);
+	configfs_add_default_group(&uvcg_streaming_class_ss.group,
+			&uvcg_streaming_class_grp.group);
+
+	config_group_init_type_name(&uvcg_streaming_grp.group,
+			"streaming", &uvcg_streaming_grp_type);
+	configfs_add_default_group(&uvcg_streaming_header_grp.group,
+			&uvcg_streaming_grp.group);
+	configfs_add_default_group(&uvcg_uncompressed_grp.group,
+			&uvcg_streaming_grp.group);
+	configfs_add_default_group(&uvcg_mjpeg_grp.group,
+			&uvcg_streaming_grp.group);
+	configfs_add_default_group(&uvcg_color_matching_grp.group,
+			&uvcg_streaming_grp.group);
+	configfs_add_default_group(&uvcg_streaming_class_grp.group,
+			&uvcg_streaming_grp.group);
+
+	config_group_init_type_name(&opts->func_inst.group,
 			"",
 			&uvc_func_type);
+	configfs_add_default_group(&uvcg_control_grp.group,
+			&opts->func_inst.group);
+	configfs_add_default_group(&uvcg_streaming_grp.group,
+			&opts->func_inst.group);
+
 	return 0;
 }