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 const 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 const struct config_item_type *type); 76 77 extern struct config_item *config_item_get(struct config_item *); 78 extern struct config_item *config_item_get_unless_zero(struct config_item *); 79 extern void config_item_put(struct config_item *); 80 81 struct config_item_type { 82 struct module *ct_owner; 83 struct configfs_item_operations *ct_item_ops; 84 struct configfs_group_operations *ct_group_ops; 85 struct configfs_attribute **ct_attrs; 86 struct configfs_bin_attribute **ct_bin_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 list_head default_groups; 98 struct list_head group_entry; 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 const 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 static inline void configfs_add_default_group(struct config_group *new_group, 126 struct config_group *group) 127 { 128 list_add_tail(&new_group->group_entry, &group->default_groups); 129 } 130 131 struct configfs_attribute { 132 const char *ca_name; 133 struct module *ca_owner; 134 umode_t ca_mode; 135 ssize_t (*show)(struct config_item *, char *); 136 ssize_t (*store)(struct config_item *, const char *, size_t); 137 }; 138 139 #define CONFIGFS_ATTR(_pfx, _name) \ 140 static struct configfs_attribute _pfx##attr_##_name = { \ 141 .ca_name = __stringify(_name), \ 142 .ca_mode = S_IRUGO | S_IWUSR, \ 143 .ca_owner = THIS_MODULE, \ 144 .show = _pfx##_name##_show, \ 145 .store = _pfx##_name##_store, \ 146 } 147 148 #define CONFIGFS_ATTR_RO(_pfx, _name) \ 149 static struct configfs_attribute _pfx##attr_##_name = { \ 150 .ca_name = __stringify(_name), \ 151 .ca_mode = S_IRUGO, \ 152 .ca_owner = THIS_MODULE, \ 153 .show = _pfx##_name##_show, \ 154 } 155 156 #define CONFIGFS_ATTR_WO(_pfx, _name) \ 157 static struct configfs_attribute _pfx##attr_##_name = { \ 158 .ca_name = __stringify(_name), \ 159 .ca_mode = S_IWUSR, \ 160 .ca_owner = THIS_MODULE, \ 161 .store = _pfx##_name##_store, \ 162 } 163 164 struct file; 165 struct vm_area_struct; 166 167 struct configfs_bin_attribute { 168 struct configfs_attribute cb_attr; /* std. attribute */ 169 void *cb_private; /* for user */ 170 size_t cb_max_size; /* max core size */ 171 ssize_t (*read)(struct config_item *, void *, size_t); 172 ssize_t (*write)(struct config_item *, const void *, size_t); 173 }; 174 175 #define CONFIGFS_BIN_ATTR(_pfx, _name, _priv, _maxsz) \ 176 static struct configfs_bin_attribute _pfx##attr_##_name = { \ 177 .cb_attr = { \ 178 .ca_name = __stringify(_name), \ 179 .ca_mode = S_IRUGO | S_IWUSR, \ 180 .ca_owner = THIS_MODULE, \ 181 }, \ 182 .cb_private = _priv, \ 183 .cb_max_size = _maxsz, \ 184 .read = _pfx##_name##_read, \ 185 .write = _pfx##_name##_write, \ 186 } 187 188 #define CONFIGFS_BIN_ATTR_RO(_pfx, _name, _priv, _maxsz) \ 189 static struct configfs_bin_attribute _pfx##attr_##_name = { \ 190 .cb_attr = { \ 191 .ca_name = __stringify(_name), \ 192 .ca_mode = S_IRUGO, \ 193 .ca_owner = THIS_MODULE, \ 194 }, \ 195 .cb_private = _priv, \ 196 .cb_max_size = _maxsz, \ 197 .read = _pfx##_name##_read, \ 198 } 199 200 #define CONFIGFS_BIN_ATTR_WO(_pfx, _name, _priv, _maxsz) \ 201 static struct configfs_bin_attribute _pfx##attr_##_name = { \ 202 .cb_attr = { \ 203 .ca_name = __stringify(_name), \ 204 .ca_mode = S_IWUSR, \ 205 .ca_owner = THIS_MODULE, \ 206 }, \ 207 .cb_private = _priv, \ 208 .cb_max_size = _maxsz, \ 209 .write = _pfx##_name##_write, \ 210 } 211 212 /* 213 * If allow_link() exists, the item can symlink(2) out to other 214 * items. If the item is a group, it may support mkdir(2). 215 * Groups supply one of make_group() and make_item(). If the 216 * group supports make_group(), one can create group children. If it 217 * supports make_item(), one can create config_item children. make_group() 218 * and make_item() return ERR_PTR() on errors. If it has 219 * default_groups on group->default_groups, it has automatically created 220 * group children. default_groups may coexist alongsize make_group() or 221 * make_item(), but if the group wishes to have only default_groups 222 * children (disallowing mkdir(2)), it need not provide either function. 223 * If the group has commit(), it supports pending and committed (active) 224 * items. 225 */ 226 struct configfs_item_operations { 227 void (*release)(struct config_item *); 228 int (*allow_link)(struct config_item *src, struct config_item *target); 229 void (*drop_link)(struct config_item *src, struct config_item *target); 230 }; 231 232 struct configfs_group_operations { 233 struct config_item *(*make_item)(struct config_group *group, const char *name); 234 struct config_group *(*make_group)(struct config_group *group, const char *name); 235 int (*commit_item)(struct config_item *item); 236 void (*disconnect_notify)(struct config_group *group, struct config_item *item); 237 void (*drop_item)(struct config_group *group, struct config_item *item); 238 }; 239 240 struct configfs_subsystem { 241 struct config_group su_group; 242 struct mutex su_mutex; 243 }; 244 245 static inline struct configfs_subsystem *to_configfs_subsystem(struct config_group *group) 246 { 247 return group ? 248 container_of(group, struct configfs_subsystem, su_group) : 249 NULL; 250 } 251 252 int configfs_register_subsystem(struct configfs_subsystem *subsys); 253 void configfs_unregister_subsystem(struct configfs_subsystem *subsys); 254 255 int configfs_register_group(struct config_group *parent_group, 256 struct config_group *group); 257 void configfs_unregister_group(struct config_group *group); 258 259 void configfs_remove_default_groups(struct config_group *group); 260 261 struct config_group * 262 configfs_register_default_group(struct config_group *parent_group, 263 const char *name, 264 const struct config_item_type *item_type); 265 void configfs_unregister_default_group(struct config_group *group); 266 267 /* These functions can sleep and can alloc with GFP_KERNEL */ 268 /* WARNING: These cannot be called underneath configfs callbacks!! */ 269 int configfs_depend_item(struct configfs_subsystem *subsys, 270 struct config_item *target); 271 void configfs_undepend_item(struct config_item *target); 272 273 /* 274 * These functions can sleep and can alloc with GFP_KERNEL 275 * NOTE: These should be called only underneath configfs callbacks. 276 * NOTE: First parameter is a caller's subsystem, not target's. 277 * WARNING: These cannot be called on newly created item 278 * (in make_group()/make_item() callback) 279 */ 280 int configfs_depend_item_unlocked(struct configfs_subsystem *caller_subsys, 281 struct config_item *target); 282 283 284 static inline void configfs_undepend_item_unlocked(struct config_item *target) 285 { 286 configfs_undepend_item(target); 287 } 288 289 #endif /* _CONFIGFS_H_ */ 290