1 /* -*- mode: c; c-basic-offset: 8; -*- 2 * vim: noexpandtab sw=8 ts=8 sts=0: 3 * 4 * configfs.h - definitions for the device driver filesystem 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public 8 * License as published by the Free Software Foundation; either 9 * version 2 of the License, or (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public 17 * License along with this program; if not, write to the 18 * Free Software Foundation, Inc., 59 Temple Place - Suite 330, 19 * Boston, MA 021110-1307, USA. 20 * 21 * Based on sysfs: 22 * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel 23 * 24 * Based on kobject.h: 25 * Copyright (c) 2002-2003 Patrick Mochel 26 * Copyright (c) 2002-2003 Open Source Development Labs 27 * 28 * configfs Copyright (C) 2005 Oracle. All rights reserved. 29 * 30 * Please read Documentation/filesystems/configfs.txt before using the 31 * configfs interface, ESPECIALLY the parts about reference counts and 32 * item destructors. 33 */ 34 35 #ifndef _CONFIGFS_H_ 36 #define _CONFIGFS_H_ 37 38 #ifdef __KERNEL__ 39 40 #include <linux/kernel.h> 41 #include <linux/types.h> 42 #include <linux/list.h> 43 #include <linux/kref.h> 44 #include <linux/mutex.h> 45 46 #include <asm/atomic.h> 47 48 #define CONFIGFS_ITEM_NAME_LEN 20 49 50 struct module; 51 52 struct configfs_item_operations; 53 struct configfs_group_operations; 54 struct configfs_attribute; 55 struct configfs_subsystem; 56 57 struct config_item { 58 char *ci_name; 59 char ci_namebuf[CONFIGFS_ITEM_NAME_LEN]; 60 struct kref ci_kref; 61 struct list_head ci_entry; 62 struct config_item *ci_parent; 63 struct config_group *ci_group; 64 struct config_item_type *ci_type; 65 struct dentry *ci_dentry; 66 }; 67 68 extern int config_item_set_name(struct config_item *, const char *, ...); 69 70 static inline char *config_item_name(struct config_item * item) 71 { 72 return item->ci_name; 73 } 74 75 extern void config_item_init(struct config_item *); 76 extern void config_item_init_type_name(struct config_item *item, 77 const char *name, 78 struct config_item_type *type); 79 80 extern struct config_item * config_item_get(struct config_item *); 81 extern void config_item_put(struct config_item *); 82 83 struct config_item_type { 84 struct module *ct_owner; 85 struct configfs_item_operations *ct_item_ops; 86 struct configfs_group_operations *ct_group_ops; 87 struct configfs_attribute **ct_attrs; 88 }; 89 90 /** 91 * group - a group of config_items of a specific type, belonging 92 * to a specific subsystem. 93 */ 94 struct config_group { 95 struct config_item cg_item; 96 struct list_head cg_children; 97 struct configfs_subsystem *cg_subsys; 98 struct config_group **default_groups; 99 }; 100 101 extern void config_group_init(struct config_group *group); 102 extern void config_group_init_type_name(struct config_group *group, 103 const char *name, 104 struct config_item_type *type); 105 106 static inline struct config_group *to_config_group(struct config_item *item) 107 { 108 return item ? container_of(item,struct config_group,cg_item) : NULL; 109 } 110 111 static inline struct config_group *config_group_get(struct config_group *group) 112 { 113 return group ? to_config_group(config_item_get(&group->cg_item)) : NULL; 114 } 115 116 static inline void config_group_put(struct config_group *group) 117 { 118 config_item_put(&group->cg_item); 119 } 120 121 extern struct config_item *config_group_find_item(struct config_group *, 122 const char *); 123 124 125 struct configfs_attribute { 126 const char *ca_name; 127 struct module *ca_owner; 128 mode_t ca_mode; 129 }; 130 131 /* 132 * Users often need to create attribute structures for their configurable 133 * attributes, containing a configfs_attribute member and function pointers 134 * for the show() and store() operations on that attribute. They can use 135 * this macro (similar to sysfs' __ATTR) to make defining attributes easier. 136 */ 137 #define __CONFIGFS_ATTR(_name, _mode, _show, _store) \ 138 { \ 139 .attr = { \ 140 .ca_name = __stringify(_name), \ 141 .ca_mode = _mode, \ 142 .ca_owner = THIS_MODULE, \ 143 }, \ 144 .show = _show, \ 145 .store = _store, \ 146 } 147 148 /* 149 * If allow_link() exists, the item can symlink(2) out to other 150 * items. If the item is a group, it may support mkdir(2). 151 * Groups supply one of make_group() and make_item(). If the 152 * group supports make_group(), one can create group children. If it 153 * supports make_item(), one can create config_item children. If it has 154 * default_groups on group->default_groups, it has automatically created 155 * group children. default_groups may coexist alongsize make_group() or 156 * make_item(), but if the group wishes to have only default_groups 157 * children (disallowing mkdir(2)), it need not provide either function. 158 * If the group has commit(), it supports pending and commited (active) 159 * items. 160 */ 161 struct configfs_item_operations { 162 void (*release)(struct config_item *); 163 ssize_t (*show_attribute)(struct config_item *, struct configfs_attribute *,char *); 164 ssize_t (*store_attribute)(struct config_item *,struct configfs_attribute *,const char *, size_t); 165 int (*allow_link)(struct config_item *src, struct config_item *target); 166 int (*drop_link)(struct config_item *src, struct config_item *target); 167 }; 168 169 struct configfs_group_operations { 170 struct config_item *(*make_item)(struct config_group *group, const char *name); 171 struct config_group *(*make_group)(struct config_group *group, const char *name); 172 int (*commit_item)(struct config_item *item); 173 void (*disconnect_notify)(struct config_group *group, struct config_item *item); 174 void (*drop_item)(struct config_group *group, struct config_item *item); 175 }; 176 177 struct configfs_subsystem { 178 struct config_group su_group; 179 struct mutex su_mutex; 180 }; 181 182 static inline struct configfs_subsystem *to_configfs_subsystem(struct config_group *group) 183 { 184 return group ? 185 container_of(group, struct configfs_subsystem, su_group) : 186 NULL; 187 } 188 189 int configfs_register_subsystem(struct configfs_subsystem *subsys); 190 void configfs_unregister_subsystem(struct configfs_subsystem *subsys); 191 192 /* These functions can sleep and can alloc with GFP_KERNEL */ 193 /* WARNING: These cannot be called underneath configfs callbacks!! */ 194 int configfs_depend_item(struct configfs_subsystem *subsys, struct config_item *target); 195 void configfs_undepend_item(struct configfs_subsystem *subsys, struct config_item *target); 196 197 #endif /* __KERNEL__ */ 198 199 #endif /* _CONFIGFS_H_ */ 200