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/types.h> 41 #include <linux/list.h> 42 #include <linux/kref.h> 43 #include <linux/mutex.h> 44 45 #include <asm/atomic.h> 46 47 #define CONFIGFS_ITEM_NAME_LEN 20 48 49 struct module; 50 51 struct configfs_item_operations; 52 struct configfs_group_operations; 53 struct configfs_attribute; 54 struct configfs_subsystem; 55 56 struct config_item { 57 char *ci_name; 58 char ci_namebuf[CONFIGFS_ITEM_NAME_LEN]; 59 struct kref ci_kref; 60 struct list_head ci_entry; 61 struct config_item *ci_parent; 62 struct config_group *ci_group; 63 struct config_item_type *ci_type; 64 struct dentry *ci_dentry; 65 }; 66 67 extern int config_item_set_name(struct config_item *, const char *, ...); 68 69 static inline char *config_item_name(struct config_item * item) 70 { 71 return item->ci_name; 72 } 73 74 extern void config_item_init(struct config_item *); 75 extern void config_item_init_type_name(struct config_item *item, 76 const char *name, 77 struct config_item_type *type); 78 79 extern struct config_item * config_item_get(struct config_item *); 80 extern void config_item_put(struct config_item *); 81 82 struct config_item_type { 83 struct module *ct_owner; 84 struct configfs_item_operations *ct_item_ops; 85 struct configfs_group_operations *ct_group_ops; 86 struct configfs_attribute **ct_attrs; 87 }; 88 89 /** 90 * group - a group of config_items of a specific type, belonging 91 * to a specific subsystem. 92 */ 93 struct config_group { 94 struct config_item cg_item; 95 struct list_head cg_children; 96 struct configfs_subsystem *cg_subsys; 97 struct config_group **default_groups; 98 }; 99 100 extern void config_group_init(struct config_group *group); 101 extern void config_group_init_type_name(struct config_group *group, 102 const char *name, 103 struct config_item_type *type); 104 105 static inline struct config_group *to_config_group(struct config_item *item) 106 { 107 return item ? container_of(item,struct config_group,cg_item) : NULL; 108 } 109 110 static inline struct config_group *config_group_get(struct config_group *group) 111 { 112 return group ? to_config_group(config_item_get(&group->cg_item)) : NULL; 113 } 114 115 static inline void config_group_put(struct config_group *group) 116 { 117 config_item_put(&group->cg_item); 118 } 119 120 extern struct config_item *config_group_find_item(struct config_group *, 121 const char *); 122 123 124 struct configfs_attribute { 125 const char *ca_name; 126 struct module *ca_owner; 127 mode_t ca_mode; 128 }; 129 130 /* 131 * Users often need to create attribute structures for their configurable 132 * attributes, containing a configfs_attribute member and function pointers 133 * for the show() and store() operations on that attribute. They can use 134 * this macro (similar to sysfs' __ATTR) to make defining attributes easier. 135 */ 136 #define __CONFIGFS_ATTR(_name, _mode, _show, _store) \ 137 { \ 138 .attr = { \ 139 .ca_name = __stringify(_name), \ 140 .ca_mode = _mode, \ 141 .ca_owner = THIS_MODULE, \ 142 }, \ 143 .show = _show, \ 144 .store = _store, \ 145 } 146 147 /* 148 * If allow_link() exists, the item can symlink(2) out to other 149 * items. If the item is a group, it may support mkdir(2). 150 * Groups supply one of make_group() and make_item(). If the 151 * group supports make_group(), one can create group children. If it 152 * supports make_item(), one can create config_item children. If it has 153 * default_groups on group->default_groups, it has automatically created 154 * group children. default_groups may coexist alongsize make_group() or 155 * make_item(), but if the group wishes to have only default_groups 156 * children (disallowing mkdir(2)), it need not provide either function. 157 * If the group has commit(), it supports pending and commited (active) 158 * items. 159 */ 160 struct configfs_item_operations { 161 void (*release)(struct config_item *); 162 ssize_t (*show_attribute)(struct config_item *, struct configfs_attribute *,char *); 163 ssize_t (*store_attribute)(struct config_item *,struct configfs_attribute *,const char *, size_t); 164 int (*allow_link)(struct config_item *src, struct config_item *target); 165 int (*drop_link)(struct config_item *src, struct config_item *target); 166 }; 167 168 struct configfs_group_operations { 169 struct config_item *(*make_item)(struct config_group *group, const char *name); 170 struct config_group *(*make_group)(struct config_group *group, const char *name); 171 int (*commit_item)(struct config_item *item); 172 void (*disconnect_notify)(struct config_group *group, struct config_item *item); 173 void (*drop_item)(struct config_group *group, struct config_item *item); 174 }; 175 176 struct configfs_subsystem { 177 struct config_group su_group; 178 struct mutex su_mutex; 179 }; 180 181 static inline struct configfs_subsystem *to_configfs_subsystem(struct config_group *group) 182 { 183 return group ? 184 container_of(group, struct configfs_subsystem, su_group) : 185 NULL; 186 } 187 188 int configfs_register_subsystem(struct configfs_subsystem *subsys); 189 void configfs_unregister_subsystem(struct configfs_subsystem *subsys); 190 191 /* These functions can sleep and can alloc with GFP_KERNEL */ 192 /* WARNING: These cannot be called underneath configfs callbacks!! */ 193 int configfs_depend_item(struct configfs_subsystem *subsys, struct config_item *target); 194 void configfs_undepend_item(struct configfs_subsystem *subsys, struct config_item *target); 195 196 #endif /* __KERNEL__ */ 197 198 #endif /* _CONFIGFS_H_ */ 199