5 files changed, 130 insertions, 32 deletions

diff --git a/kernel/fs/configfs/dir.c b/kernel/fs/configfs/dir.c
index c81ce7f20..a7a1b218f 100644
--- a/kernel/fs/configfs/dir.c
+++ b/kernel/fs/configfs/dir.c
@@ -1636,6 +1636,116 @@ const struct file_operations configfs_dir_operations = {
 	.iterate	= configfs_readdir,
 };
 
+/**
+ * configfs_register_group - creates a parent-child relation between two groups
+ * @parent_group:	parent group
+ * @group:		child group
+ *
+ * link groups, creates dentry for the child and attaches it to the
+ * parent dentry.
+ *
+ * Return: 0 on success, negative errno code on error
+ */
+int configfs_register_group(struct config_group *parent_group,
+			    struct config_group *group)
+{
+	struct configfs_subsystem *subsys = parent_group->cg_subsys;
+	struct dentry *parent;
+	int ret;
+
+	mutex_lock(&subsys->su_mutex);
+	link_group(parent_group, group);
+	mutex_unlock(&subsys->su_mutex);
+
+	parent = parent_group->cg_item.ci_dentry;
+
+	mutex_lock_nested(&d_inode(parent)->i_mutex, I_MUTEX_PARENT);
+	ret = create_default_group(parent_group, group);
+	if (!ret) {
+		spin_lock(&configfs_dirent_lock);
+		configfs_dir_set_ready(group->cg_item.ci_dentry->d_fsdata);
+		spin_unlock(&configfs_dirent_lock);
+	}
+	mutex_unlock(&d_inode(parent)->i_mutex);
+	return ret;
+}
+EXPORT_SYMBOL(configfs_register_group);
+
+/**
+ * configfs_unregister_group() - unregisters a child group from its parent
+ * @group: parent group to be unregistered
+ *
+ * Undoes configfs_register_group()
+ */
+void configfs_unregister_group(struct config_group *group)
+{
+	struct configfs_subsystem *subsys = group->cg_subsys;
+	struct dentry *dentry = group->cg_item.ci_dentry;
+	struct dentry *parent = group->cg_item.ci_parent->ci_dentry;
+
+	mutex_lock_nested(&d_inode(parent)->i_mutex, I_MUTEX_PARENT);
+	spin_lock(&configfs_dirent_lock);
+	configfs_detach_prep(dentry, NULL);
+	spin_unlock(&configfs_dirent_lock);
+
+	configfs_detach_group(&group->cg_item);
+	d_inode(dentry)->i_flags |= S_DEAD;
+	dont_mount(dentry);
+	d_delete(dentry);
+	mutex_unlock(&d_inode(parent)->i_mutex);
+
+	dput(dentry);
+
+	mutex_lock(&subsys->su_mutex);
+	unlink_group(group);
+	mutex_unlock(&subsys->su_mutex);
+}
+EXPORT_SYMBOL(configfs_unregister_group);
+
+/**
+ * configfs_register_default_group() - allocates and registers a child group
+ * @parent_group:	parent group
+ * @name:		child group name
+ * @item_type:		child item type description
+ *
+ * boilerplate to allocate and register a child group with its parent. We need
+ * kzalloc'ed memory because child's default_group is initially empty.
+ *
+ * Return: allocated config group or ERR_PTR() on error
+ */
+struct config_group *
+configfs_register_default_group(struct config_group *parent_group,
+				const char *name,
+				struct config_item_type *item_type)
+{
+	int ret;
+	struct config_group *group;
+
+	group = kzalloc(sizeof(*group), GFP_KERNEL);
+	if (!group)
+		return ERR_PTR(-ENOMEM);
+	config_group_init_type_name(group, name, item_type);
+
+	ret = configfs_register_group(parent_group, group);
+	if (ret) {
+		kfree(group);
+		return ERR_PTR(ret);
+	}
+	return group;
+}
+EXPORT_SYMBOL(configfs_register_default_group);
+
+/**
+ * configfs_unregister_default_group() - unregisters and frees a child group
+ * @group:	the group to act on
+ */
+void configfs_unregister_default_group(struct config_group *group)
+{
+	configfs_unregister_group(group);
+	kfree(group);
+}
+EXPORT_SYMBOL(configfs_unregister_default_group);
+
 int configfs_register_subsystem(struct configfs_subsystem *subsys)
 {
 	int err;
diff --git a/kernel/fs/configfs/file.c b/kernel/fs/configfs/file.c
index 403269ffc..d39099ea7 100644
--- a/kernel/fs/configfs/file.c
+++ b/kernel/fs/configfs/file.c
@@ -65,7 +65,6 @@ static int fill_read_buffer(struct dentry * dentry, struct configfs_buffer * buf
 {
 	struct configfs_attribute * attr = to_attr(dentry);
 	struct config_item * item = to_item(dentry->d_parent);
-	struct configfs_item_operations * ops = buffer->ops;
 	int ret = 0;
 	ssize_t count;
 
@@ -74,7 +73,8 @@ static int fill_read_buffer(struct dentry * dentry, struct configfs_buffer * buf
 	if (!buffer->page)
 		return -ENOMEM;
 
-	count = ops->show_attribute(item,attr,buffer->page);
+	count = attr->show(item, buffer->page);
+
 	buffer->needs_read_fill = 0;
 	BUG_ON(count > (ssize_t)SIMPLE_ATTR_SIZE);
 	if (count >= 0)
@@ -171,9 +171,8 @@ flush_write_buffer(struct dentry * dentry, struct configfs_buffer * buffer, size
 {
 	struct configfs_attribute * attr = to_attr(dentry);
 	struct config_item * item = to_item(dentry->d_parent);
-	struct configfs_item_operations * ops = buffer->ops;
 
-	return ops->store_attribute(item,attr,buffer->page,count);
+	return attr->store(item, buffer->page, count);
 }
 
 
@@ -237,8 +236,7 @@ static int check_perm(struct inode * inode, struct file * file)
 	 * and we must have a store method.
 	 */
 	if (file->f_mode & FMODE_WRITE) {
-
-		if (!(inode->i_mode & S_IWUGO) || !ops->store_attribute)
+		if (!(inode->i_mode & S_IWUGO) || !attr->store)
 			goto Eaccess;
 
 	}
@@ -248,7 +246,7 @@ static int check_perm(struct inode * inode, struct file * file)
 	 * must be a show method for it.
 	 */
 	if (file->f_mode & FMODE_READ) {
-		if (!(inode->i_mode & S_IRUGO) || !ops->show_attribute)
+		if (!(inode->i_mode & S_IRUGO) || !attr->show)
 			goto Eaccess;
 	}
 
diff --git a/kernel/fs/configfs/inode.c b/kernel/fs/configfs/inode.c
index 8d89f5fd0..eae87575e 100644
--- a/kernel/fs/configfs/inode.c
+++ b/kernel/fs/configfs/inode.c
@@ -236,7 +236,7 @@ void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent)
 
 	if (dentry) {
 		spin_lock(&dentry->d_lock);
-		if (!d_unhashed(dentry) && d_really_is_positive(dentry)) {
+		if (simple_positive(dentry)) {
 			dget_dlock(dentry);
 			__d_drop(dentry);
 			spin_unlock(&dentry->d_lock);
diff --git a/kernel/fs/configfs/item.c b/kernel/fs/configfs/item.c
index e65f9ffbb..b863a09cd 100644
--- a/kernel/fs/configfs/item.c
+++ b/kernel/fs/configfs/item.c
@@ -47,12 +47,11 @@ static void config_item_release(struct kref *kref);
  *	config_item_init - initialize item.
  *	@item:	item in question.
  */
-void config_item_init(struct config_item *item)
+static void config_item_init(struct config_item *item)
 {
 	kref_init(&item->ci_kref);
 	INIT_LIST_HEAD(&item->ci_entry);
 }
-EXPORT_SYMBOL(config_item_init);
 
 /**
  *	config_item_set_name - Set the name of an item
@@ -116,7 +115,7 @@ void config_item_init_type_name(struct config_item *item,
 				const char *name,
 				struct config_item_type *type)
 {
-	config_item_set_name(item, name);
+	config_item_set_name(item, "%s", name);
 	item->ci_type = type;
 	config_item_init(item);
 }
@@ -125,7 +124,7 @@ EXPORT_SYMBOL(config_item_init_type_name);
 void config_group_init_type_name(struct config_group *group, const char *name,
 			 struct config_item_type *type)
 {
-	config_item_set_name(&group->cg_item, name);
+	config_item_set_name(&group->cg_item, "%s", name);
 	group->cg_item.ci_type = type;
 	config_group_init(group);
 }
diff --git a/kernel/fs/configfs/symlink.c b/kernel/fs/configfs/symlink.c
index cc9f2546e..ec5c8325b 100644
--- a/kernel/fs/configfs/symlink.c
+++ b/kernel/fs/configfs/symlink.c
@@ -279,36 +279,27 @@ static int configfs_getlink(struct dentry *dentry, char * path)
 
 }
 
-static void *configfs_follow_link(struct dentry *dentry, struct nameidata *nd)
+static const char *configfs_follow_link(struct dentry *dentry, void **cookie)
 {
-	int error = -ENOMEM;
 	unsigned long page = get_zeroed_page(GFP_KERNEL);
+	int error;
 
-	if (page) {
-		error = configfs_getlink(dentry, (char *)page);
-		if (!error) {
-			nd_set_link(nd, (char *)page);
-			return (void *)page;
-		}
-	}
-
-	nd_set_link(nd, ERR_PTR(error));
-	return NULL;
-}
+	if (!page)
+		return ERR_PTR(-ENOMEM);
 
-static void configfs_put_link(struct dentry *dentry, struct nameidata *nd,
-			      void *cookie)
-{
-	if (cookie) {
-		unsigned long page = (unsigned long)cookie;
-		free_page(page);
+	error = configfs_getlink(dentry, (char *)page);
+	if (!error) {
+		return *cookie = (void *)page;
 	}
+
+	free_page(page);
+	return ERR_PTR(error);
 }
 
 const struct inode_operations configfs_symlink_inode_operations = {
 	.follow_link = configfs_follow_link,
 	.readlink = generic_readlink,
-	.put_link = configfs_put_link,
+	.put_link = free_page_put_link,
 	.setattr = configfs_setattr,
 };