diff options
Diffstat (limited to 'fs/configfs/item.c')
| -rw-r--r-- | fs/configfs/item.c | 206 |
1 files changed, 206 insertions, 0 deletions
diff --git a/fs/configfs/item.c b/fs/configfs/item.c new file mode 100644 index 000000000..99d491cd0 --- /dev/null +++ b/fs/configfs/item.c @@ -0,0 +1,206 @@ +/* -*- mode: c; c-basic-offset: 8; -*- + * vim: noexpandtab sw=8 ts=8 sts=0: + * + * item.c - library routines for handling generic config items + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public + * License along with this program; if not, write to the + * Free Software Foundation, Inc., 59 Temple Place - Suite 330, + * Boston, MA 021110-1307, USA. + * + * Based on kobject: + * kobject is Copyright (c) 2002-2003 Patrick Mochel + * + * configfs Copyright (C) 2005 Oracle. All rights reserved. + * + * Please see the file Documentation/filesystems/configfs/configfs.txt for + * critical information about using the config_item interface. + */ + +#include <linux/string.h> +#include <linux/module.h> +#include <linux/stat.h> +#include <linux/slab.h> + +#include <linux/configfs.h> + + +static inline struct config_item *to_item(struct list_head *entry) +{ + return container_of(entry, struct config_item, ci_entry); +} + +/* Evil kernel */ +static void config_item_release(struct kref *kref); + +/** + * config_item_init - initialize item. + * @item: item in question. + */ +static void config_item_init(struct config_item *item) +{ + kref_init(&item->ci_kref); + INIT_LIST_HEAD(&item->ci_entry); +} + +/** + * config_item_set_name - Set the name of an item + * @item: item. + * @fmt: The vsnprintf()'s format string. + * + * If strlen(name) >= CONFIGFS_ITEM_NAME_LEN, then use a + * dynamically allocated string that @item->ci_name points to. + * Otherwise, use the static @item->ci_namebuf array. + */ +int config_item_set_name(struct config_item *item, const char *fmt, ...) +{ + int limit = CONFIGFS_ITEM_NAME_LEN; + int need; + va_list args; + char *name; + + /* + * First, try the static array + */ + va_start(args, fmt); + need = vsnprintf(item->ci_namebuf, limit, fmt, args); + va_end(args); + if (need < limit) + name = item->ci_namebuf; + else { + va_start(args, fmt); + name = kvasprintf(GFP_KERNEL, fmt, args); + va_end(args); + if (!name) + return -EFAULT; + } + + /* Free the old name, if necessary. */ + if (item->ci_name && item->ci_name != item->ci_namebuf) + kfree(item->ci_name); + + /* Now, set the new name */ + item->ci_name = name; + return 0; +} +EXPORT_SYMBOL(config_item_set_name); + +void config_item_init_type_name(struct config_item *item, + const char *name, + const struct config_item_type *type) +{ + config_item_set_name(item, "%s", name); + item->ci_type = type; + config_item_init(item); +} +EXPORT_SYMBOL(config_item_init_type_name); + +void config_group_init_type_name(struct config_group *group, const char *name, + const struct config_item_type *type) +{ + config_item_set_name(&group->cg_item, "%s", name); + group->cg_item.ci_type = type; + config_group_init(group); +} +EXPORT_SYMBOL(config_group_init_type_name); + +struct config_item *config_item_get(struct config_item *item) +{ + if (item) + kref_get(&item->ci_kref); + return item; +} +EXPORT_SYMBOL(config_item_get); + +struct config_item *config_item_get_unless_zero(struct config_item *item) +{ + if (item && kref_get_unless_zero(&item->ci_kref)) + return item; + return NULL; +} +EXPORT_SYMBOL(config_item_get_unless_zero); + +static void config_item_cleanup(struct config_item *item) +{ + const struct config_item_type *t = item->ci_type; + struct config_group *s = item->ci_group; + struct config_item *parent = item->ci_parent; + + pr_debug("config_item %s: cleaning up\n", config_item_name(item)); + if (item->ci_name != item->ci_namebuf) + kfree(item->ci_name); + item->ci_name = NULL; + if (t && t->ct_item_ops && t->ct_item_ops->release) + t->ct_item_ops->release(item); + if (s) + config_group_put(s); + if (parent) + config_item_put(parent); +} + +static void config_item_release(struct kref *kref) +{ + config_item_cleanup(container_of(kref, struct config_item, ci_kref)); +} + +/** + * config_item_put - decrement refcount for item. + * @item: item. + * + * Decrement the refcount, and if 0, call config_item_cleanup(). + */ +void config_item_put(struct config_item *item) +{ + if (item) + kref_put(&item->ci_kref, config_item_release); +} +EXPORT_SYMBOL(config_item_put); + +/** + * config_group_init - initialize a group for use + * @group: config_group + */ +void config_group_init(struct config_group *group) +{ + config_item_init(&group->cg_item); + INIT_LIST_HEAD(&group->cg_children); + INIT_LIST_HEAD(&group->default_groups); +} +EXPORT_SYMBOL(config_group_init); + +/** + * config_group_find_item - search for item in group. + * @group: group we're looking in. + * @name: item's name. + * + * Iterate over @group->cg_list, looking for a matching config_item. + * If matching item is found take a reference and return the item. + * Caller must have locked group via @group->cg_subsys->su_mtx. + */ +struct config_item *config_group_find_item(struct config_group *group, + const char *name) +{ + struct list_head *entry; + struct config_item *ret = NULL; + + list_for_each(entry, &group->cg_children) { + struct config_item *item = to_item(entry); + if (config_item_name(item) && + !strcmp(config_item_name(item), name)) { + ret = config_item_get(item); + break; + } + } + return ret; +} +EXPORT_SYMBOL(config_group_find_item); |