[PATCH RFC v2 03/12] fs/configfs: separate out configfs_{link,unlink}_root()

[hare]

From: Hannes Reinecke <hare@xxxxxxx>

Separate out functions to link and unlink subsystem groups.

Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
---
 fs/configfs/dir.c | 68 ++++++++++++++++++++++++++++++++++---------------------
 1 file changed, 42 insertions(+), 26 deletions(-)

diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
index 2cd64c13538699683487b0669e8950f5c7bedd54..c9e1ae47fb0d7796121fa6b45aeb10a832a69cff 100644
--- a/fs/configfs/dir.c
+++ b/fs/configfs/dir.c
@@ -1861,31 +1861,19 @@ void configfs_unregister_default_group(struct config_group *group)
 }
 EXPORT_SYMBOL(configfs_unregister_default_group);
 
-int configfs_register_subsystem(struct configfs_subsystem *subsys)
+static int configfs_link_root(struct configfs_super_info  *info,
+			      struct configfs_subsystem *subsys,
+			      struct dentry *root)
 {
-	struct configfs_super_info *info = configfs_get_super_info(0);
 	struct config_group *group = &subsys->su_group;
 	struct dentry *dentry;
-	struct dentry *root;
 	struct configfs_dirent *sd;
 	struct configfs_fragment *frag;
 	int err;
 
-	if (IS_ERR(info))
-		return PTR_ERR(info);
-
 	frag = new_fragment();
-	if (!frag) {
-		configfs_put_super_info(info);
+	if (!frag)
 		return -ENOMEM;
-	}
-
-	root = configfs_pin_fs();
-	if (IS_ERR(root)) {
-		put_fragment(frag);
-		configfs_put_super_info(info);
-		return PTR_ERR(root);
-	}
 
 	if (!group->cg_item.ci_name)
 		group->cg_item.ci_name = group->cg_item.ci_namebuf;
@@ -1923,32 +1911,47 @@ int configfs_register_subsystem(struct configfs_subsystem *subsys)
 		mutex_lock(&info->subsys_mutex);
 		unlink_group(group);
 		mutex_unlock(&info->subsys_mutex);
-		configfs_release_fs();
 	}
 	put_fragment(frag);
-	configfs_put_super_info(info);
 	return err;
 }
 
-void configfs_unregister_subsystem(struct configfs_subsystem *subsys)
+int configfs_register_subsystem(struct configfs_subsystem *subsys)
 {
 	struct configfs_super_info *info = configfs_get_super_info(0);
+	struct dentry *root;
+	int err;
+
+	if (WARN_ON(IS_ERR(info)))
+		return PTR_ERR(info);
+
+	root = configfs_pin_fs();
+	if (IS_ERR(root)) {
+		err = PTR_ERR(root);
+		goto out_put;
+	}
+
+	err = configfs_link_root(info, subsys, root);
+	if (err)
+		configfs_release_fs();
+
+out_put:
+	configfs_put_super_info(info);
+	return err;
+}
+
+static bool configfs_unlink_root(struct configfs_subsystem *subsys)
+{
 	struct config_group *group = &subsys->su_group;
 	struct dentry *dentry = dget(group->cg_item.ci_dentry);
 	struct dentry *root = dentry->d_sb->s_root;
 	struct configfs_dirent *sd = dentry->d_fsdata;
 	struct configfs_fragment *frag = sd->s_frag;
 
-	if (WARN_ON(IS_ERR(info))) {
-		dput(dentry);
-		return;
-	}
-
 	if (dentry->d_parent != root) {
 		pr_err("Tried to unregister non-subsystem!\n");
 		dput(dentry);
-		configfs_put_super_info(info);
-		return;
+		return false;
 	}
 
 	down_write(&frag->frag_sem);
@@ -1976,6 +1979,19 @@ void configfs_unregister_subsystem(struct configfs_subsystem *subsys)
 	inode_unlock(d_inode(root));
 
 	dput(dentry);
+	return true;
+}
+
+void configfs_unregister_subsystem(struct configfs_subsystem *subsys)
+{
+	struct configfs_super_info *info = configfs_get_super_info(0);
+	struct config_group *group = &subsys->su_group;
+
+	if (WARN_ON(IS_ERR(info)))
+		return;
+
+	if (!configfs_unlink_root(subsys))
+		return;
 
 	mutex_lock(&info->subsys_mutex);
 	unlink_group(group);

-- 
2.51.0