diff options
Diffstat (limited to 'kernel/include/linux/configfs.h')
| -rw-r--r-- | kernel/include/linux/configfs.h | 260 |
1 files changed, 260 insertions, 0 deletions
diff --git a/kernel/include/linux/configfs.h b/kernel/include/linux/configfs.h new file mode 100644 index 000000000..34025df61 --- /dev/null +++ b/kernel/include/linux/configfs.h @@ -0,0 +1,260 @@ +/* -*- mode: c; c-basic-offset: 8; -*- + * vim: noexpandtab sw=8 ts=8 sts=0: + * + * configfs.h - definitions for the device driver filesystem + * + * 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 sysfs: + * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel + * + * Based on kobject.h: + * Copyright (c) 2002-2003 Patrick Mochel + * Copyright (c) 2002-2003 Open Source Development Labs + * + * configfs Copyright (C) 2005 Oracle. All rights reserved. + * + * Please read Documentation/filesystems/configfs/configfs.txt before using + * the configfs interface, ESPECIALLY the parts about reference counts and + * item destructors. + */ + +#ifndef _CONFIGFS_H_ +#define _CONFIGFS_H_ + +#include <linux/kernel.h> +#include <linux/types.h> +#include <linux/list.h> +#include <linux/kref.h> +#include <linux/mutex.h> +#include <linux/err.h> + +#include <linux/atomic.h> + +#define CONFIGFS_ITEM_NAME_LEN 20 + +struct module; + +struct configfs_item_operations; +struct configfs_group_operations; +struct configfs_attribute; +struct configfs_subsystem; + +struct config_item { + char *ci_name; + char ci_namebuf[CONFIGFS_ITEM_NAME_LEN]; + struct kref ci_kref; + struct list_head ci_entry; + struct config_item *ci_parent; + struct config_group *ci_group; + struct config_item_type *ci_type; + struct dentry *ci_dentry; +}; + +extern int config_item_set_name(struct config_item *, const char *, ...); + +static inline char *config_item_name(struct config_item * item) +{ + return item->ci_name; +} + +extern void config_item_init(struct config_item *); +extern void config_item_init_type_name(struct config_item *item, + const char *name, + struct config_item_type *type); + +extern struct config_item * config_item_get(struct config_item *); +extern void config_item_put(struct config_item *); + +struct config_item_type { + struct module *ct_owner; + struct configfs_item_operations *ct_item_ops; + struct configfs_group_operations *ct_group_ops; + struct configfs_attribute **ct_attrs; +}; + +/** + * group - a group of config_items of a specific type, belonging + * to a specific subsystem. + */ +struct config_group { + struct config_item cg_item; + struct list_head cg_children; + struct configfs_subsystem *cg_subsys; + struct config_group **default_groups; +}; + +extern void config_group_init(struct config_group *group); +extern void config_group_init_type_name(struct config_group *group, + const char *name, + struct config_item_type *type); + +static inline struct config_group *to_config_group(struct config_item *item) +{ + return item ? container_of(item,struct config_group,cg_item) : NULL; +} + +static inline struct config_group *config_group_get(struct config_group *group) +{ + return group ? to_config_group(config_item_get(&group->cg_item)) : NULL; +} + +static inline void config_group_put(struct config_group *group) +{ + config_item_put(&group->cg_item); +} + +extern struct config_item *config_group_find_item(struct config_group *, + const char *); + + +struct configfs_attribute { + const char *ca_name; + struct module *ca_owner; + umode_t ca_mode; +}; + +/* + * Users often need to create attribute structures for their configurable + * attributes, containing a configfs_attribute member and function pointers + * for the show() and store() operations on that attribute. If they don't + * need anything else on the extended attribute structure, they can use + * this macro to define it The argument _item is the name of the + * config_item structure. + */ +#define CONFIGFS_ATTR_STRUCT(_item) \ +struct _item##_attribute { \ + struct configfs_attribute attr; \ + ssize_t (*show)(struct _item *, char *); \ + ssize_t (*store)(struct _item *, const char *, size_t); \ +} + +/* + * With the extended attribute structure, users can use this macro + * (similar to sysfs' __ATTR) to make defining attributes easier. + * An example: + * #define MYITEM_ATTR(_name, _mode, _show, _store) \ + * struct myitem_attribute childless_attr_##_name = \ + * __CONFIGFS_ATTR(_name, _mode, _show, _store) + */ +#define __CONFIGFS_ATTR(_name, _mode, _show, _store) \ +{ \ + .attr = { \ + .ca_name = __stringify(_name), \ + .ca_mode = _mode, \ + .ca_owner = THIS_MODULE, \ + }, \ + .show = _show, \ + .store = _store, \ +} +/* Here is a readonly version, only requiring a show() operation */ +#define __CONFIGFS_ATTR_RO(_name, _show) \ +{ \ + .attr = { \ + .ca_name = __stringify(_name), \ + .ca_mode = 0444, \ + .ca_owner = THIS_MODULE, \ + }, \ + .show = _show, \ +} + +/* + * With these extended attributes, the simple show_attribute() and + * store_attribute() operations need to call the show() and store() of the + * attributes. This is a common pattern, so we provide a macro to define + * them. The argument _item is the name of the config_item structure. + * This macro expects the attributes to be named "struct <name>_attribute" + * and the function to_<name>() to exist; + */ +#define CONFIGFS_ATTR_OPS(_item) \ +static ssize_t _item##_attr_show(struct config_item *item, \ + struct configfs_attribute *attr, \ + char *page) \ +{ \ + struct _item *_item = to_##_item(item); \ + struct _item##_attribute *_item##_attr = \ + container_of(attr, struct _item##_attribute, attr); \ + ssize_t ret = 0; \ + \ + if (_item##_attr->show) \ + ret = _item##_attr->show(_item, page); \ + return ret; \ +} \ +static ssize_t _item##_attr_store(struct config_item *item, \ + struct configfs_attribute *attr, \ + const char *page, size_t count) \ +{ \ + struct _item *_item = to_##_item(item); \ + struct _item##_attribute *_item##_attr = \ + container_of(attr, struct _item##_attribute, attr); \ + ssize_t ret = -EINVAL; \ + \ + if (_item##_attr->store) \ + ret = _item##_attr->store(_item, page, count); \ + return ret; \ +} + +/* + * If allow_link() exists, the item can symlink(2) out to other + * items. If the item is a group, it may support mkdir(2). + * Groups supply one of make_group() and make_item(). If the + * group supports make_group(), one can create group children. If it + * supports make_item(), one can create config_item children. make_group() + * and make_item() return ERR_PTR() on errors. If it has + * default_groups on group->default_groups, it has automatically created + * group children. default_groups may coexist alongsize make_group() or + * make_item(), but if the group wishes to have only default_groups + * children (disallowing mkdir(2)), it need not provide either function. + * If the group has commit(), it supports pending and committed (active) + * items. + */ +struct configfs_item_operations { + void (*release)(struct config_item *); + ssize_t (*show_attribute)(struct config_item *, struct configfs_attribute *,char *); + ssize_t (*store_attribute)(struct config_item *,struct configfs_attribute *,const char *, size_t); + int (*allow_link)(struct config_item *src, struct config_item *target); + int (*drop_link)(struct config_item *src, struct config_item *target); +}; + +struct configfs_group_operations { + struct config_item *(*make_item)(struct config_group *group, const char *name); + struct config_group *(*make_group)(struct config_group *group, const char *name); + int (*commit_item)(struct config_item *item); + void (*disconnect_notify)(struct config_group *group, struct config_item *item); + void (*drop_item)(struct config_group *group, struct config_item *item); +}; + +struct configfs_subsystem { + struct config_group su_group; + struct mutex su_mutex; +}; + +static inline struct configfs_subsystem *to_configfs_subsystem(struct config_group *group) +{ + return group ? + container_of(group, struct configfs_subsystem, su_group) : + NULL; +} + +int configfs_register_subsystem(struct configfs_subsystem *subsys); +void configfs_unregister_subsystem(struct configfs_subsystem *subsys); + +/* 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); +void configfs_undepend_item(struct configfs_subsystem *subsys, struct config_item *target); + +#endif /* _CONFIGFS_H_ */ |