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_bin_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 __printf(2, 3) 69 int config_item_set_name(struct config_item *, const char *, ...); 70 71 static inline char *config_item_name(struct config_item * item) 72 { 73 return item->ci_name; 74 } 75 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 struct configfs_bin_attribute **ct_bin_attrs; 89 }; 90 91 /** 92 * group - a group of config_items of a specific type, belonging 93 * to a specific subsystem. 94 */ 95 struct config_group { 96 struct config_item cg_item; 97 struct list_head cg_children; 98 struct configfs_subsystem *cg_subsys; 99 struct list_head default_groups; 100 struct list_head group_entry; 101 }; 102 103 extern void config_group_init(struct config_group *group); 104 extern void config_group_init_type_name(struct config_group *group, 105 const char *name, 106 struct config_item_type *type); 107 108 static inline struct config_group *to_config_group(struct config_item *item) 109 { 110 return item ? container_of(item,struct config_group,cg_item) : NULL; 111 } 112 113 static inline struct config_group *config_group_get(struct config_group *group) 114 { 115 return group ? to_config_group(config_item_get(&group->cg_item)) : NULL; 116 } 117 118 static inline void config_group_put(struct config_group *group) 119 { 120 config_item_put(&group->cg_item); 121 } 122 123 extern struct config_item *config_group_find_item(struct config_group *, 124 const char *); 125 126 127 static inline void configfs_add_default_group(struct config_group *new_group, 128 struct config_group *group) 129 { 130 list_add_tail(&new_group->group_entry, &group->default_groups); 131 } 132 133 struct configfs_attribute { 134 const char *ca_name; 135 struct module *ca_owner; 136 umode_t ca_mode; 137 ssize_t (*show)(struct config_item *, char *); 138 ssize_t (*store)(struct config_item *, const char *, size_t); 139 }; 140 141 #define CONFIGFS_ATTR(_pfx, _name) \ 142 static struct configfs_attribute _pfx##attr_##_name = { \ 143 .ca_name = __stringify(_name), \ 144 .ca_mode = S_IRUGO | S_IWUSR, \ 145 .ca_owner = THIS_MODULE, \ 146 .show = _pfx##_name##_show, \ 147 .store = _pfx##_name##_store, \ 148 } 149 150 #define CONFIGFS_ATTR_RO(_pfx, _name) \ 151 static struct configfs_attribute _pfx##attr_##_name = { \ 152 .ca_name = __stringify(_name), \ 153 .ca_mode = S_IRUGO, \ 154 .ca_owner = THIS_MODULE, \ 155 .show = _pfx##_name##_show, \ 156 } 157 158 #define CONFIGFS_ATTR_WO(_pfx, _name) \ 159 static struct configfs_attribute _pfx##attr_##_name = { \ 160 .ca_name = __stringify(_name), \ 161 .ca_mode = S_IWUSR, \ 162 .ca_owner = THIS_MODULE, \ 163 .store = _pfx##_name##_store, \ 164 } 165 166 struct file; 167 struct vm_area_struct; 168 169 struct configfs_bin_attribute { 170 struct configfs_attribute cb_attr; /* std. attribute */ 171 void *cb_private; /* for user */ 172 size_t cb_max_size; /* max core size */ 173 ssize_t (*read)(struct config_item *, void *, size_t); 174 ssize_t (*write)(struct config_item *, const void *, size_t); 175 }; 176 177 #define CONFIGFS_BIN_ATTR(_pfx, _name, _priv, _maxsz) \ 178 static struct configfs_bin_attribute _pfx##attr_##_name = { \ 179 .cb_attr = { \ 180 .ca_name = __stringify(_name), \ 181 .ca_mode = S_IRUGO | S_IWUSR, \ 182 .ca_owner = THIS_MODULE, \ 183 }, \ 184 .cb_private = _priv, \ 185 .cb_max_size = _maxsz, \ 186 .read = _pfx##_name##_read, \ 187 .write = _pfx##_name##_write, \ 188 } 189 190 #define CONFIGFS_BIN_ATTR_RO(_pfx, _name, _priv, _maxsz) \ 191 static struct configfs_bin_attribute _pfx##attr_##_name = { \ 192 .cb_attr = { \ 193 .ca_name = __stringify(_name), \ 194 .ca_mode = S_IRUGO, \ 195 .ca_owner = THIS_MODULE, \ 196 }, \ 197 .cb_private = _priv, \ 198 .cb_max_size = _maxsz, \ 199 .read = _pfx##_name##_read, \ 200 } 201 202 #define CONFIGFS_BIN_ATTR_WO(_pfx, _name, _priv, _maxsz) \ 203 static struct configfs_bin_attribute _pfx##attr_##_name = { \ 204 .cb_attr = { \ 205 .ca_name = __stringify(_name), \ 206 .ca_mode = S_IWUSR, \ 207 .ca_owner = THIS_MODULE, \ 208 }, \ 209 .cb_private = _priv, \ 210 .cb_max_size = _maxsz, \ 211 .write = _pfx##_name##_write, \ 212 } 213 214 /* 215 * If allow_link() exists, the item can symlink(2) out to other 216 * items. If the item is a group, it may support mkdir(2). 217 * Groups supply one of make_group() and make_item(). If the 218 * group supports make_group(), one can create group children. If it 219 * supports make_item(), one can create config_item children. make_group() 220 * and make_item() return ERR_PTR() on errors. If it has 221 * default_groups on group->default_groups, it has automatically created 222 * group children. default_groups may coexist alongsize make_group() or 223 * make_item(), but if the group wishes to have only default_groups 224 * children (disallowing mkdir(2)), it need not provide either function. 225 * If the group has commit(), it supports pending and committed (active) 226 * items. 227 */ 228 struct configfs_item_operations { 229 void (*release)(struct config_item *); 230 int (*allow_link)(struct config_item *src, struct config_item *target); 231 int (*drop_link)(struct config_item *src, struct config_item *target); 232 }; 233 234 struct configfs_group_operations { 235 struct config_item *(*make_item)(struct config_group *group, const char *name); 236 struct config_group *(*make_group)(struct config_group *group, const char *name); 237 int (*commit_item)(struct config_item *item); 238 void (*disconnect_notify)(struct config_group *group, struct config_item *item); 239 void (*drop_item)(struct config_group *group, struct config_item *item); 240 }; 241 242 struct configfs_subsystem { 243 struct config_group su_group; 244 struct mutex su_mutex; 245 }; 246 247 static inline struct configfs_subsystem *to_configfs_subsystem(struct config_group *group) 248 { 249 return group ? 250 container_of(group, struct configfs_subsystem, su_group) : 251 NULL; 252 } 253 254 int configfs_register_subsystem(struct configfs_subsystem *subsys); 255 void configfs_unregister_subsystem(struct configfs_subsystem *subsys); 256 257 int configfs_register_group(struct config_group *parent_group, 258 struct config_group *group); 259 void configfs_unregister_group(struct config_group *group); 260 261 void configfs_remove_default_groups(struct config_group *group); 262 263 struct config_group * 264 configfs_register_default_group(struct config_group *parent_group, 265 const char *name, 266 struct config_item_type *item_type); 267 void configfs_unregister_default_group(struct config_group *group); 268 269 /* These functions can sleep and can alloc with GFP_KERNEL */ 270 /* WARNING: These cannot be called underneath configfs callbacks!! */ 271 int configfs_depend_item(struct configfs_subsystem *subsys, 272 struct config_item *target); 273 void configfs_undepend_item(struct config_item *target); 274 275 /* 276 * These functions can sleep and can alloc with GFP_KERNEL 277 * NOTE: These should be called only underneath configfs callbacks. 278 * NOTE: First parameter is a caller's subsystem, not target's. 279 * WARNING: These cannot be called on newly created item 280 * (in make_group()/make_item() callback) 281 */ 282 int configfs_depend_item_unlocked(struct configfs_subsystem *caller_subsys, 283 struct config_item *target); 284 285 286 static inline void configfs_undepend_item_unlocked(struct config_item *target) 287 { 288 configfs_undepend_item(target); 289 } 290 291 #endif /* _CONFIGFS_H_ */ 292