We don't want to hardcode default groups at subsystem creation time. We export: * configfs_register_group * configfs_unregister_group to allow drivers to programatically create/destroy groups later, after module init time. This is needed for IIO configfs support. Suggested-by: Lars-Peter Clausen <lars@xxxxxxxxxx> Signed-off-by: Daniel Baluta <daniel.baluta@xxxxxxxxx> --- fs/configfs/dir.c | 102 +++++++++++++++++++++++++++++++++++++++++++++++ include/linux/configfs.h | 8 ++++ 2 files changed, 110 insertions(+) diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c index c81ce7f..bf76795 100644 --- a/fs/configfs/dir.c +++ b/fs/configfs/dir.c @@ -1636,6 +1636,108 @@ const struct file_operations configfs_dir_operations = { .iterate = configfs_readdir, }; +/** + * configfs_alloc_group() - allocate a configfs group + * @name: group name + * @item_type: config_item associated with the allocated group + * + * Dynamically allocates and initialize a group specified by name and + * config_item_type. We need kzalloc'ed memory because default_group + * is empty. + * + * Return: allocated config group or ERR_PTR() on error + */ +struct config_group * +configfs_alloc_group(const char *name, struct config_item_type *item_type) +{ + 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); + + return group; +} +EXPORT_SYMBOL(configfs_alloc_group); + +/** + * configfs_free_group() - frees memory for a configfs group + * @group: group to be 'eliberated' + */ +void configfs_free_group(struct config_group *group) +{ + kfree(group); +} +EXPORT_SYMBOL(configfs_free_group); + +/** + * 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 condigfs_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); + int configfs_register_subsystem(struct configfs_subsystem *subsys) { int err; diff --git a/include/linux/configfs.h b/include/linux/configfs.h index 63a36e8..c522a5e 100644 --- a/include/linux/configfs.h +++ b/include/linux/configfs.h @@ -252,6 +252,14 @@ static inline struct configfs_subsystem *to_configfs_subsystem(struct config_gro int configfs_register_subsystem(struct configfs_subsystem *subsys); void configfs_unregister_subsystem(struct configfs_subsystem *subsys); +struct config_group * +configfs_alloc_group(const char *name, struct config_item_type *item_type); +void configfs_free_group(struct config_group *group); + +int configfs_register_group(struct config_group *parent_group, + struct config_group *group); +void configfs_unregister_group(struct config_group *group); + /* These functions can sleep and can alloc with GFP_KERNEL */ /* WARNING: These cannot be called underneath configfs callbacks!! */ int configfs_depend_item(struct configfs_subsystem *subsys, struct config_item *target); -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html