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1/* SPDX-License-Identifier: GPL-2.0-or-later */2/*3 * configfs.h - definitions for the device driver filesystem4 *5 * Based on sysfs:6 * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel7 *8 * Based on kobject.h:9 * Copyright (c) 2002-2003 Patrick Mochel10 * Copyright (c) 2002-2003 Open Source Development Labs11 *12 * configfs Copyright (C) 2005 Oracle. All rights reserved.13 *14 * Please read Documentation/filesystems/configfs.rst before using15 * the configfs interface, ESPECIALLY the parts about reference counts and16 * item destructors.17 */18 19#ifndef _CONFIGFS_H_20#define _CONFIGFS_H_21 22#include <linux/stat.h> /* S_IRUGO */23#include <linux/types.h> /* ssize_t */24#include <linux/list.h> /* struct list_head */25#include <linux/kref.h> /* struct kref */26#include <linux/mutex.h> /* struct mutex */27 28#define CONFIGFS_ITEM_NAME_LEN 2029 30struct module;31 32struct configfs_item_operations;33struct configfs_group_operations;34struct configfs_attribute;35struct configfs_bin_attribute;36struct configfs_subsystem;37 38struct config_item {39 char *ci_name;40 char ci_namebuf[CONFIGFS_ITEM_NAME_LEN];41 struct kref ci_kref;42 struct list_head ci_entry;43 struct config_item *ci_parent;44 struct config_group *ci_group;45 const struct config_item_type *ci_type;46 struct dentry *ci_dentry;47};48 49extern __printf(2, 3)50int config_item_set_name(struct config_item *, const char *, ...);51 52static inline char *config_item_name(struct config_item * item)53{54 return item->ci_name;55}56 57extern void config_item_init_type_name(struct config_item *item,58 const char *name,59 const struct config_item_type *type);60 61extern struct config_item *config_item_get(struct config_item *);62extern struct config_item *config_item_get_unless_zero(struct config_item *);63extern void config_item_put(struct config_item *);64 65struct config_item_type {66 struct module *ct_owner;67 struct configfs_item_operations *ct_item_ops;68 struct configfs_group_operations *ct_group_ops;69 struct configfs_attribute **ct_attrs;70 struct configfs_bin_attribute **ct_bin_attrs;71};72 73/**74 * group - a group of config_items of a specific type, belonging75 * to a specific subsystem.76 */77struct config_group {78 struct config_item cg_item;79 struct list_head cg_children;80 struct configfs_subsystem *cg_subsys;81 struct list_head default_groups;82 struct list_head group_entry;83};84 85extern void config_group_init(struct config_group *group);86extern void config_group_init_type_name(struct config_group *group,87 const char *name,88 const struct config_item_type *type);89 90static inline struct config_group *to_config_group(struct config_item *item)91{92 return item ? container_of(item,struct config_group,cg_item) : NULL;93}94 95static inline struct config_group *config_group_get(struct config_group *group)96{97 return group ? to_config_group(config_item_get(&group->cg_item)) : NULL;98}99 100static inline void config_group_put(struct config_group *group)101{102 config_item_put(&group->cg_item);103}104 105extern struct config_item *config_group_find_item(struct config_group *,106 const char *);107 108 109static inline void configfs_add_default_group(struct config_group *new_group,110 struct config_group *group)111{112 list_add_tail(&new_group->group_entry, &group->default_groups);113}114 115struct configfs_attribute {116 const char *ca_name;117 struct module *ca_owner;118 umode_t ca_mode;119 ssize_t (*show)(struct config_item *, char *);120 ssize_t (*store)(struct config_item *, const char *, size_t);121};122 123#define CONFIGFS_ATTR(_pfx, _name) \124static struct configfs_attribute _pfx##attr_##_name = { \125 .ca_name = __stringify(_name), \126 .ca_mode = S_IRUGO | S_IWUSR, \127 .ca_owner = THIS_MODULE, \128 .show = _pfx##_name##_show, \129 .store = _pfx##_name##_store, \130}131 132#define CONFIGFS_ATTR_RO(_pfx, _name) \133static struct configfs_attribute _pfx##attr_##_name = { \134 .ca_name = __stringify(_name), \135 .ca_mode = S_IRUGO, \136 .ca_owner = THIS_MODULE, \137 .show = _pfx##_name##_show, \138}139 140#define CONFIGFS_ATTR_WO(_pfx, _name) \141static struct configfs_attribute _pfx##attr_##_name = { \142 .ca_name = __stringify(_name), \143 .ca_mode = S_IWUSR, \144 .ca_owner = THIS_MODULE, \145 .store = _pfx##_name##_store, \146}147 148struct file;149struct vm_area_struct;150 151struct configfs_bin_attribute {152 struct configfs_attribute cb_attr; /* std. attribute */153 void *cb_private; /* for user */154 size_t cb_max_size; /* max core size */155 ssize_t (*read)(struct config_item *, void *, size_t);156 ssize_t (*write)(struct config_item *, const void *, size_t);157};158 159#define CONFIGFS_BIN_ATTR(_pfx, _name, _priv, _maxsz) \160static struct configfs_bin_attribute _pfx##attr_##_name = { \161 .cb_attr = { \162 .ca_name = __stringify(_name), \163 .ca_mode = S_IRUGO | S_IWUSR, \164 .ca_owner = THIS_MODULE, \165 }, \166 .cb_private = _priv, \167 .cb_max_size = _maxsz, \168 .read = _pfx##_name##_read, \169 .write = _pfx##_name##_write, \170}171 172#define CONFIGFS_BIN_ATTR_RO(_pfx, _name, _priv, _maxsz) \173static struct configfs_bin_attribute _pfx##attr_##_name = { \174 .cb_attr = { \175 .ca_name = __stringify(_name), \176 .ca_mode = S_IRUGO, \177 .ca_owner = THIS_MODULE, \178 }, \179 .cb_private = _priv, \180 .cb_max_size = _maxsz, \181 .read = _pfx##_name##_read, \182}183 184#define CONFIGFS_BIN_ATTR_WO(_pfx, _name, _priv, _maxsz) \185static struct configfs_bin_attribute _pfx##attr_##_name = { \186 .cb_attr = { \187 .ca_name = __stringify(_name), \188 .ca_mode = S_IWUSR, \189 .ca_owner = THIS_MODULE, \190 }, \191 .cb_private = _priv, \192 .cb_max_size = _maxsz, \193 .write = _pfx##_name##_write, \194}195 196/*197 * If allow_link() exists, the item can symlink(2) out to other198 * items. If the item is a group, it may support mkdir(2).199 * Groups supply one of make_group() and make_item(). If the200 * group supports make_group(), one can create group children. If it201 * supports make_item(), one can create config_item children. make_group()202 * and make_item() return ERR_PTR() on errors. If it has203 * default_groups on group->default_groups, it has automatically created204 * group children. default_groups may coexist alongsize make_group() or205 * make_item(), but if the group wishes to have only default_groups206 * children (disallowing mkdir(2)), it need not provide either function.207 */208struct configfs_item_operations {209 void (*release)(struct config_item *);210 int (*allow_link)(struct config_item *src, struct config_item *target);211 void (*drop_link)(struct config_item *src, struct config_item *target);212};213 214struct configfs_group_operations {215 struct config_item *(*make_item)(struct config_group *group, const char *name);216 struct config_group *(*make_group)(struct config_group *group, const char *name);217 void (*disconnect_notify)(struct config_group *group, struct config_item *item);218 void (*drop_item)(struct config_group *group, struct config_item *item);219 bool (*is_visible)(struct config_item *item, struct configfs_attribute *attr, int n);220 bool (*is_bin_visible)(struct config_item *item, struct configfs_bin_attribute *attr,221 int n);222};223 224struct configfs_subsystem {225 struct config_group su_group;226 struct mutex su_mutex;227};228 229static inline struct configfs_subsystem *to_configfs_subsystem(struct config_group *group)230{231 return group ?232 container_of(group, struct configfs_subsystem, su_group) :233 NULL;234}235 236int configfs_register_subsystem(struct configfs_subsystem *subsys);237void configfs_unregister_subsystem(struct configfs_subsystem *subsys);238 239int configfs_register_group(struct config_group *parent_group,240 struct config_group *group);241void configfs_unregister_group(struct config_group *group);242 243void configfs_remove_default_groups(struct config_group *group);244 245struct config_group *246configfs_register_default_group(struct config_group *parent_group,247 const char *name,248 const struct config_item_type *item_type);249void configfs_unregister_default_group(struct config_group *group);250 251/* These functions can sleep and can alloc with GFP_KERNEL */252/* WARNING: These cannot be called underneath configfs callbacks!! */253int configfs_depend_item(struct configfs_subsystem *subsys,254 struct config_item *target);255void configfs_undepend_item(struct config_item *target);256 257/*258 * These functions can sleep and can alloc with GFP_KERNEL259 * NOTE: These should be called only underneath configfs callbacks.260 * NOTE: First parameter is a caller's subsystem, not target's.261 * WARNING: These cannot be called on newly created item262 * (in make_group()/make_item() callback)263 */264int configfs_depend_item_unlocked(struct configfs_subsystem *caller_subsys,265 struct config_item *target);266 267 268static inline void configfs_undepend_item_unlocked(struct config_item *target)269{270 configfs_undepend_item(target);271}272 273#endif /* _CONFIGFS_H_ */274