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/stat.h> /* S_IRUGO */ 39 #include <linux/types.h> /* ssize_t */ 40 #include <linux/list.h> /* struct list_head */ 41 #include <linux/kref.h> /* struct kref */ 42 #include <linux/mutex.h> /* struct mutex */ 43 44 #define CONFIGFS_ITEM_NAME_LEN 20 45 46 struct module; 47 48 struct configfs_item_operations; 49 struct configfs_group_operations; 50 struct configfs_attribute; 51 struct configfs_bin_attribute; 52 struct configfs_subsystem; 53 54 struct config_item { 55 char *ci_name; 56 char ci_namebuf[CONFIGFS_ITEM_NAME_LEN]; 57 struct kref ci_kref; 58 struct list_head ci_entry; 59 struct config_item *ci_parent; 60 struct config_group *ci_group; 61 struct config_item_type *ci_type; 62 struct dentry *ci_dentry; 63 }; 64 65 extern __printf(2, 3) 66 int config_item_set_name(struct config_item *, const char *, ...); 67 68 static inline char *config_item_name(struct config_item * item) 69 { 70 return item->ci_name; 71 } 72 73 extern void config_item_init_type_name(struct config_item *item, 74 const char *name, 75 struct config_item_type *type); 76 77 extern struct config_item * config_item_get(struct config_item *); 78 extern void config_item_put(struct config_item *); 79 80 struct config_item_type { 81 struct module *ct_owner; 82 struct configfs_item_operations *ct_item_ops; 83 struct configfs_group_operations *ct_group_ops; 84 struct configfs_attribute **ct_attrs; 85 struct configfs_bin_attribute **ct_bin_attrs; 86 }; 87 88 /** 89 * group - a group of config_items of a specific type, belonging 90 * to a specific subsystem. 91 */ 92 struct config_group { 93 struct config_item cg_item; 94 struct list_head cg_children; 95 struct configfs_subsystem *cg_subsys; 96 struct list_head default_groups; 97 struct list_head group_entry; 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 static inline void configfs_add_default_group(struct config_group *new_group, 125 struct config_group *group) 126 { 127 list_add_tail(&new_group->group_entry, &group->default_groups); 128 } 129 130 struct configfs_attribute { 131 const char *ca_name; 132 struct module *ca_owner; 133 umode_t ca_mode; 134 ssize_t (*show)(struct config_item *, char *); 135 ssize_t (*store)(struct config_item *, const char *, size_t); 136 }; 137 138 #define CONFIGFS_ATTR(_pfx, _name) \ 139 static struct configfs_attribute _pfx##attr_##_name = { \ 140 .ca_name = __stringify(_name), \ 141 .ca_mode = S_IRUGO | S_IWUSR, \ 142 .ca_owner = THIS_MODULE, \ 143 .show = _pfx##_name##_show, \ 144 .store = _pfx##_name##_store, \ 145 } 146 147 #define CONFIGFS_ATTR_RO(_pfx, _name) \ 148 static struct configfs_attribute _pfx##attr_##_name = { \ 149 .ca_name = __stringify(_name), \ 150 .ca_mode = S_IRUGO, \ 151 .ca_owner = THIS_MODULE, \ 152 .show = _pfx##_name##_show, \ 153 } 154 155 #define CONFIGFS_ATTR_WO(_pfx, _name) \ 156 static struct configfs_attribute _pfx##attr_##_name = { \ 157 .ca_name = __stringify(_name), \ 158 .ca_mode = S_IWUSR, \ 159 .ca_owner = THIS_MODULE, \ 160 .store = _pfx##_name##_store, \ 161 } 162 163 struct file; 164 struct vm_area_struct; 165 166 struct configfs_bin_attribute { 167 struct configfs_attribute cb_attr; /* std. attribute */ 168 void *cb_private; /* for user */ 169 size_t cb_max_size; /* max core size */ 170 ssize_t (*read)(struct config_item *, void *, size_t); 171 ssize_t (*write)(struct config_item *, const void *, size_t); 172 }; 173 174 #define CONFIGFS_BIN_ATTR(_pfx, _name, _priv, _maxsz) \ 175 static struct configfs_bin_attribute _pfx##attr_##_name = { \ 176 .cb_attr = { \ 177 .ca_name = __stringify(_name), \ 178 .ca_mode = S_IRUGO | S_IWUSR, \ 179 .ca_owner = THIS_MODULE, \ 180 }, \ 181 .cb_private = _priv, \ 182 .cb_max_size = _maxsz, \ 183 .read = _pfx##_name##_read, \ 184 .write = _pfx##_name##_write, \ 185 } 186 187 #define CONFIGFS_BIN_ATTR_RO(_pfx, _name, _priv, _maxsz) \ 188 static struct configfs_bin_attribute _pfx##attr_##_name = { \ 189 .cb_attr = { \ 190 .ca_name = __stringify(_name), \ 191 .ca_mode = S_IRUGO, \ 192 .ca_owner = THIS_MODULE, \ 193 }, \ 194 .cb_private = _priv, \ 195 .cb_max_size = _maxsz, \ 196 .read = _pfx##_name##_read, \ 197 } 198 199 #define CONFIGFS_BIN_ATTR_WO(_pfx, _name, _priv, _maxsz) \ 200 static struct configfs_bin_attribute _pfx##attr_##_name = { \ 201 .cb_attr = { \ 202 .ca_name = __stringify(_name), \ 203 .ca_mode = S_IWUSR, \ 204 .ca_owner = THIS_MODULE, \ 205 }, \ 206 .cb_private = _priv, \ 207 .cb_max_size = _maxsz, \ 208 .write = _pfx##_name##_write, \ 209 } 210 211 /* 212 * If allow_link() exists, the item can symlink(2) out to other 213 * items. If the item is a group, it may support mkdir(2). 214 * Groups supply one of make_group() and make_item(). If the 215 * group supports make_group(), one can create group children. If it 216 * supports make_item(), one can create config_item children. make_group() 217 * and make_item() return ERR_PTR() on errors. If it has 218 * default_groups on group->default_groups, it has automatically created 219 * group children. default_groups may coexist alongsize make_group() or 220 * make_item(), but if the group wishes to have only default_groups 221 * children (disallowing mkdir(2)), it need not provide either function. 222 * If the group has commit(), it supports pending and committed (active) 223 * items. 224 */ 225 struct configfs_item_operations { 226 void (*release)(struct config_item *); 227 int (*allow_link)(struct config_item *src, struct config_item *target); 228 void (*drop_link)(struct config_item *src, struct config_item *target); 229 }; 230 231 struct configfs_group_operations { 232 struct config_item *(*make_item)(struct config_group *group, const char *name); 233 struct config_group *(*make_group)(struct config_group *group, const char *name); 234 int (*commit_item)(struct config_item *item); 235 void (*disconnect_notify)(struct config_group *group, struct config_item *item); 236 void (*drop_item)(struct config_group *group, struct config_item *item); 237 }; 238 239 struct configfs_subsystem { 240 struct config_group su_group; 241 struct mutex su_mutex; 242 }; 243 244 static inline struct configfs_subsystem *to_configfs_subsystem(struct config_group *group) 245 { 246 return group ? 247 container_of(group, struct configfs_subsystem, su_group) : 248 NULL; 249 } 250 251 int configfs_register_subsystem(struct configfs_subsystem *subsys); 252 void configfs_unregister_subsystem(struct configfs_subsystem *subsys); 253 254 int configfs_register_group(struct config_group *parent_group, 255 struct config_group *group); 256 void configfs_unregister_group(struct config_group *group); 257 258 void configfs_remove_default_groups(struct config_group *group); 259 260 struct config_group * 261 configfs_register_default_group(struct config_group *parent_group, 262 const char *name, 263 struct config_item_type *item_type); 264 void configfs_unregister_default_group(struct config_group *group); 265 266 /* These functions can sleep and can alloc with GFP_KERNEL */ 267 /* WARNING: These cannot be called underneath configfs callbacks!! */ 268 int configfs_depend_item(struct configfs_subsystem *subsys, 269 struct config_item *target); 270 void configfs_undepend_item(struct config_item *target); 271 272 /* 273 * These functions can sleep and can alloc with GFP_KERNEL 274 * NOTE: These should be called only underneath configfs callbacks. 275 * NOTE: First parameter is a caller's subsystem, not target's. 276 * WARNING: These cannot be called on newly created item 277 * (in make_group()/make_item() callback) 278 */ 279 int configfs_depend_item_unlocked(struct configfs_subsystem *caller_subsys, 280 struct config_item *target); 281 282 283 static inline void configfs_undepend_item_unlocked(struct config_item *target) 284 { 285 configfs_undepend_item(target); 286 } 287 288 #endif /* _CONFIGFS_H_ */ 289