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