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/configfs.txt before using 31 * the configfs interface, ESPECIALLY the parts about reference counts and 32 * item destructors. 33 */ 34 35 #ifndef _CONFIGFS_H_ 36 #define _CONFIGFS_H_ 37 38 #include <linux/kernel.h> 39 #include <linux/types.h> 40 #include <linux/list.h> 41 #include <linux/kref.h> 42 #include <linux/mutex.h> 43 #include <linux/err.h> 44 45 #include <linux/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 __printf(2, 3) 68 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_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 umode_t ca_mode; 128 ssize_t (*show)(struct config_item *, char *); 129 ssize_t (*store)(struct config_item *, const char *, size_t); 130 }; 131 132 #define CONFIGFS_ATTR(_pfx, _name) \ 133 static struct configfs_attribute _pfx##attr_##_name = { \ 134 .ca_name = __stringify(_name), \ 135 .ca_mode = S_IRUGO | S_IWUSR, \ 136 .ca_owner = THIS_MODULE, \ 137 .show = _pfx##_name##_show, \ 138 .store = _pfx##_name##_store, \ 139 } 140 141 #define CONFIGFS_ATTR_RO(_pfx, _name) \ 142 static struct configfs_attribute _pfx##attr_##_name = { \ 143 .ca_name = __stringify(_name), \ 144 .ca_mode = S_IRUGO, \ 145 .ca_owner = THIS_MODULE, \ 146 .show = _pfx##_name##_show, \ 147 } 148 149 #define CONFIGFS_ATTR_WO(_pfx, _name) \ 150 static struct configfs_attribute _pfx##attr_##_name = { \ 151 .ca_name = __stringify(_name), \ 152 .ca_mode = S_IWUSR, \ 153 .ca_owner = THIS_MODULE, \ 154 .store = _pfx##_name##_store, \ 155 } 156 157 /* 158 * If allow_link() exists, the item can symlink(2) out to other 159 * items. If the item is a group, it may support mkdir(2). 160 * Groups supply one of make_group() and make_item(). If the 161 * group supports make_group(), one can create group children. If it 162 * supports make_item(), one can create config_item children. make_group() 163 * and make_item() return ERR_PTR() on errors. If it has 164 * default_groups on group->default_groups, it has automatically created 165 * group children. default_groups may coexist alongsize make_group() or 166 * make_item(), but if the group wishes to have only default_groups 167 * children (disallowing mkdir(2)), it need not provide either function. 168 * If the group has commit(), it supports pending and committed (active) 169 * items. 170 */ 171 struct configfs_item_operations { 172 void (*release)(struct config_item *); 173 int (*allow_link)(struct config_item *src, struct config_item *target); 174 int (*drop_link)(struct config_item *src, struct config_item *target); 175 }; 176 177 struct configfs_group_operations { 178 struct config_item *(*make_item)(struct config_group *group, const char *name); 179 struct config_group *(*make_group)(struct config_group *group, const char *name); 180 int (*commit_item)(struct config_item *item); 181 void (*disconnect_notify)(struct config_group *group, struct config_item *item); 182 void (*drop_item)(struct config_group *group, struct config_item *item); 183 }; 184 185 struct configfs_subsystem { 186 struct config_group su_group; 187 struct mutex su_mutex; 188 }; 189 190 static inline struct configfs_subsystem *to_configfs_subsystem(struct config_group *group) 191 { 192 return group ? 193 container_of(group, struct configfs_subsystem, su_group) : 194 NULL; 195 } 196 197 int configfs_register_subsystem(struct configfs_subsystem *subsys); 198 void configfs_unregister_subsystem(struct configfs_subsystem *subsys); 199 200 /* These functions can sleep and can alloc with GFP_KERNEL */ 201 /* WARNING: These cannot be called underneath configfs callbacks!! */ 202 int configfs_depend_item(struct configfs_subsystem *subsys, struct config_item *target); 203 void configfs_undepend_item(struct configfs_subsystem *subsys, struct config_item *target); 204 205 #endif /* _CONFIGFS_H_ */ 206