/* -*- 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_ */