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>

1 files changed, 40 insertions, 163 deletions

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;