These changes are the raw update to linux-4.4.6-rt14. Kernel sources

[kvmfornfv.git] / kernel / fs / configfs / dir.c

diff --git a/kernel/fs/configfs/dir.c b/kernel/fs/configfs/dir.c
index c81ce7f..a7a1b21 100644 (file)
--- 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;