1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 /* -*- mode: c; c-basic-offset: 8; -*- 3 * vim: noexpandtab sw=8 ts=8 sts=0: 4 * 5 * configfs.h - definitions for the device driver filesystem 6 * 7 * Based on sysfs: 8 * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel 9 * 10 * Based on kobject.h: 11 * Copyright (c) 2002-2003 Patrick Mochel 12 * Copyright (c) 2002-2003 Open Source Development Labs 13 * 14 * configfs Copyright (C) 2005 Oracle. All rights reserved. 15 * 16 * Please read Documentation/filesystems/configfs.rst before using 17 * the configfs interface, ESPECIALLY the parts about reference counts and 18 * item destructors. 19 */ 20 21 #ifndef _CONFIGFS_H_ 22 #define _CONFIGFS_H_ 23 24 #include <linux/stat.h> /* S_IRUGO */ 25 #include <linux/types.h> /* ssize_t */ 26 #include <linux/list.h> /* struct list_head */ 27 #include <linux/kref.h> /* struct kref */ 28 #include <linux/mutex.h> /* struct mutex */ 29 30 #define CONFIGFS_ITEM_NAME_LEN 20 31 32 struct module; 33 34 struct configfs_item_operations; 35 struct configfs_group_operations; 36 struct configfs_attribute; 37 struct configfs_bin_attribute; 38 struct configfs_subsystem; 39 40 struct config_item { 41 char *ci_name; 42 char ci_namebuf[CONFIGFS_ITEM_NAME_LEN]; 43 struct kref ci_kref; 44 struct list_head ci_entry; 45 struct config_item *ci_parent; 46 struct config_group *ci_group; 47 const struct config_item_type *ci_type; 48 struct dentry *ci_dentry; 49 }; 50 51 extern __printf(2, 3) 52 int config_item_set_name(struct config_item *, const char *, ...); 53 54 static inline char *config_item_name(struct config_item * item) 55 { 56 return item->ci_name; 57 } 58 59 extern void config_item_init_type_name(struct config_item *item, 60 const char *name, 61 const struct config_item_type *type); 62 63 extern struct config_item *config_item_get(struct config_item *); 64 extern struct config_item *config_item_get_unless_zero(struct config_item *); 65 extern void config_item_put(struct config_item *); 66 67 struct config_item_type { 68 struct module *ct_owner; 69 struct configfs_item_operations *ct_item_ops; 70 struct configfs_group_operations *ct_group_ops; 71 struct configfs_attribute **ct_attrs; 72 struct configfs_bin_attribute **ct_bin_attrs; 73 }; 74 75 /** 76 * group - a group of config_items of a specific type, belonging 77 * to a specific subsystem. 78 */ 79 struct config_group { 80 struct config_item cg_item; 81 struct list_head cg_children; 82 struct configfs_subsystem *cg_subsys; 83 struct list_head default_groups; 84 struct list_head group_entry; 85 }; 86 87 extern void config_group_init(struct config_group *group); 88 extern void config_group_init_type_name(struct config_group *group, 89 const char *name, 90 const struct config_item_type *type); 91 92 static inline struct config_group *to_config_group(struct config_item *item) 93 { 94 return item ? container_of(item,struct config_group,cg_item) : NULL; 95 } 96 97 static inline struct config_group *config_group_get(struct config_group *group) 98 { 99 return group ? to_config_group(config_item_get(&group->cg_item)) : NULL; 100 } 101 102 static inline void config_group_put(struct config_group *group) 103 { 104 config_item_put(&group->cg_item); 105 } 106 107 extern struct config_item *config_group_find_item(struct config_group *, 108 const char *); 109 110 111 static inline void configfs_add_default_group(struct config_group *new_group, 112 struct config_group *group) 113 { 114 list_add_tail(&new_group->group_entry, &group->default_groups); 115 } 116 117 struct configfs_attribute { 118 const char *ca_name; 119 struct module *ca_owner; 120 umode_t ca_mode; 121 ssize_t (*show)(struct config_item *, char *); 122 ssize_t (*store)(struct config_item *, const char *, size_t); 123 }; 124 125 #define CONFIGFS_ATTR(_pfx, _name) \ 126 static struct configfs_attribute _pfx##attr_##_name = { \ 127 .ca_name = __stringify(_name), \ 128 .ca_mode = S_IRUGO | S_IWUSR, \ 129 .ca_owner = THIS_MODULE, \ 130 .show = _pfx##_name##_show, \ 131 .store = _pfx##_name##_store, \ 132 } 133 134 #define CONFIGFS_ATTR_RO(_pfx, _name) \ 135 static struct configfs_attribute _pfx##attr_##_name = { \ 136 .ca_name = __stringify(_name), \ 137 .ca_mode = S_IRUGO, \ 138 .ca_owner = THIS_MODULE, \ 139 .show = _pfx##_name##_show, \ 140 } 141 142 #define CONFIGFS_ATTR_WO(_pfx, _name) \ 143 static struct configfs_attribute _pfx##attr_##_name = { \ 144 .ca_name = __stringify(_name), \ 145 .ca_mode = S_IWUSR, \ 146 .ca_owner = THIS_MODULE, \ 147 .store = _pfx##_name##_store, \ 148 } 149 150 struct file; 151 struct vm_area_struct; 152 153 struct configfs_bin_attribute { 154 struct configfs_attribute cb_attr; /* std. attribute */ 155 void *cb_private; /* for user */ 156 size_t cb_max_size; /* max core size */ 157 ssize_t (*read)(struct config_item *, void *, size_t); 158 ssize_t (*write)(struct config_item *, const void *, size_t); 159 }; 160 161 #define CONFIGFS_BIN_ATTR(_pfx, _name, _priv, _maxsz) \ 162 static struct configfs_bin_attribute _pfx##attr_##_name = { \ 163 .cb_attr = { \ 164 .ca_name = __stringify(_name), \ 165 .ca_mode = S_IRUGO | S_IWUSR, \ 166 .ca_owner = THIS_MODULE, \ 167 }, \ 168 .cb_private = _priv, \ 169 .cb_max_size = _maxsz, \ 170 .read = _pfx##_name##_read, \ 171 .write = _pfx##_name##_write, \ 172 } 173 174 #define CONFIGFS_BIN_ATTR_RO(_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, \ 179 .ca_owner = THIS_MODULE, \ 180 }, \ 181 .cb_private = _priv, \ 182 .cb_max_size = _maxsz, \ 183 .read = _pfx##_name##_read, \ 184 } 185 186 #define CONFIGFS_BIN_ATTR_WO(_pfx, _name, _priv, _maxsz) \ 187 static struct configfs_bin_attribute _pfx##attr_##_name = { \ 188 .cb_attr = { \ 189 .ca_name = __stringify(_name), \ 190 .ca_mode = S_IWUSR, \ 191 .ca_owner = THIS_MODULE, \ 192 }, \ 193 .cb_private = _priv, \ 194 .cb_max_size = _maxsz, \ 195 .write = _pfx##_name##_write, \ 196 } 197 198 /* 199 * If allow_link() exists, the item can symlink(2) out to other 200 * items. If the item is a group, it may support mkdir(2). 201 * Groups supply one of make_group() and make_item(). If the 202 * group supports make_group(), one can create group children. If it 203 * supports make_item(), one can create config_item children. make_group() 204 * and make_item() return ERR_PTR() on errors. If it has 205 * default_groups on group->default_groups, it has automatically created 206 * group children. default_groups may coexist alongsize make_group() or 207 * make_item(), but if the group wishes to have only default_groups 208 * children (disallowing mkdir(2)), it need not provide either function. 209 * If the group has commit(), it supports pending and committed (active) 210 * items. 211 */ 212 struct configfs_item_operations { 213 void (*release)(struct config_item *); 214 int (*allow_link)(struct config_item *src, struct config_item *target); 215 void (*drop_link)(struct config_item *src, struct config_item *target); 216 }; 217 218 struct configfs_group_operations { 219 struct config_item *(*make_item)(struct config_group *group, const char *name); 220 struct config_group *(*make_group)(struct config_group *group, const char *name); 221 int (*commit_item)(struct config_item *item); 222 void (*disconnect_notify)(struct config_group *group, struct config_item *item); 223 void (*drop_item)(struct config_group *group, struct config_item *item); 224 }; 225 226 struct configfs_subsystem { 227 struct config_group su_group; 228 struct mutex su_mutex; 229 }; 230 231 static inline struct configfs_subsystem *to_configfs_subsystem(struct config_group *group) 232 { 233 return group ? 234 container_of(group, struct configfs_subsystem, su_group) : 235 NULL; 236 } 237 238 int configfs_register_subsystem(struct configfs_subsystem *subsys); 239 void configfs_unregister_subsystem(struct configfs_subsystem *subsys); 240 241 int configfs_register_group(struct config_group *parent_group, 242 struct config_group *group); 243 void configfs_unregister_group(struct config_group *group); 244 245 void configfs_remove_default_groups(struct config_group *group); 246 247 struct config_group * 248 configfs_register_default_group(struct config_group *parent_group, 249 const char *name, 250 const struct config_item_type *item_type); 251 void configfs_unregister_default_group(struct config_group *group); 252 253 /* These functions can sleep and can alloc with GFP_KERNEL */ 254 /* WARNING: These cannot be called underneath configfs callbacks!! */ 255 int configfs_depend_item(struct configfs_subsystem *subsys, 256 struct config_item *target); 257 void configfs_undepend_item(struct config_item *target); 258 259 /* 260 * These functions can sleep and can alloc with GFP_KERNEL 261 * NOTE: These should be called only underneath configfs callbacks. 262 * NOTE: First parameter is a caller's subsystem, not target's. 263 * WARNING: These cannot be called on newly created item 264 * (in make_group()/make_item() callback) 265 */ 266 int configfs_depend_item_unlocked(struct configfs_subsystem *caller_subsys, 267 struct config_item *target); 268 269 270 static inline void configfs_undepend_item_unlocked(struct config_item *target) 271 { 272 configfs_undepend_item(target); 273 } 274 275 #endif /* _CONFIGFS_H_ */ 276