[mirror_ubuntu-bionic-kernel.git] / include / linux / configfs.h

/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * configfs.h - definitions for the device driver filesystem
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 *
 * Based on sysfs:
 * 	sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
 *
 * Based on kobject.h:
 *      Copyright (c) 2002-2003	Patrick Mochel
 *      Copyright (c) 2002-2003	Open Source Development Labs
 *
 * configfs Copyright (C) 2005 Oracle.  All rights reserved.
 *
 * Please read Documentation/filesystems/configfs/configfs.txt before using
 * the configfs interface, ESPECIALLY the parts about reference counts and
 * item destructors.
 */

#ifndef _CONFIGFS_H_
#define _CONFIGFS_H_

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/list.h>
#include <linux/kref.h>
#include <linux/mutex.h>
#include <linux/err.h>

#include <linux/atomic.h>

#define CONFIGFS_ITEM_NAME_LEN	20

struct module;

struct configfs_item_operations;
struct configfs_group_operations;
struct configfs_attribute;
struct configfs_subsystem;

struct config_item {
	char			*ci_name;
	char			ci_namebuf[CONFIGFS_ITEM_NAME_LEN];
	struct kref		ci_kref;
	struct list_head	ci_entry;
	struct config_item	*ci_parent;
	struct config_group	*ci_group;
	struct config_item_type	*ci_type;
	struct dentry		*ci_dentry;
};

extern int config_item_set_name(struct config_item *, const char *, ...);

static inline char *config_item_name(struct config_item * item)
{
	return item->ci_name;
}

extern void config_item_init(struct config_item *);
extern void config_item_init_type_name(struct config_item *item,
				       const char *name,
				       struct config_item_type *type);

extern struct config_item * config_item_get(struct config_item *);
extern void config_item_put(struct config_item *);

struct config_item_type {
	struct module				*ct_owner;
	struct configfs_item_operations		*ct_item_ops;
	struct configfs_group_operations	*ct_group_ops;
	struct configfs_attribute		**ct_attrs;
};

/**
 *	group - a group of config_items of a specific type, belonging
 *	to a specific subsystem.
 */
struct config_group {
	struct config_item		cg_item;
	struct list_head		cg_children;
	struct configfs_subsystem 	*cg_subsys;
	struct config_group		**default_groups;
};

extern void config_group_init(struct config_group *group);
extern void config_group_init_type_name(struct config_group *group,
					const char *name,
					struct config_item_type *type);

static inline struct config_group *to_config_group(struct config_item *item)
{
	return item ? container_of(item,struct config_group,cg_item) : NULL;
}

static inline struct config_group *config_group_get(struct config_group *group)
{
	return group ? to_config_group(config_item_get(&group->cg_item)) : NULL;
}

static inline void config_group_put(struct config_group *group)
{
	config_item_put(&group->cg_item);
}

extern struct config_item *config_group_find_item(struct config_group *,
						  const char *);


struct configfs_attribute {
	const char		*ca_name;
	struct module 		*ca_owner;
	umode_t			ca_mode;
};

/*
 * Users often need to create attribute structures for their configurable
 * attributes, containing a configfs_attribute member and function pointers
 * for the show() and store() operations on that attribute. If they don't
 * need anything else on the extended attribute structure, they can use
 * this macro to define it  The argument _item is the name of the
 * config_item structure.
 */
#define CONFIGFS_ATTR_STRUCT(_item)					\
struct _item##_attribute {						\
	struct configfs_attribute attr;					\
	ssize_t (*show)(struct _item *, char *);			\
	ssize_t (*store)(struct _item *, const char *, size_t);		\
}

/*
 * With the extended attribute structure, users can use this macro
 * (similar to sysfs' __ATTR) to make defining attributes easier.
 * An example:
 * #define MYITEM_ATTR(_name, _mode, _show, _store)	\
 * struct myitem_attribute childless_attr_##_name =	\
 *         __CONFIGFS_ATTR(_name, _mode, _show, _store)
 */
#define __CONFIGFS_ATTR(_name, _mode, _show, _store)			\
{									\
	.attr	= {							\
			.ca_name = __stringify(_name),			\
			.ca_mode = _mode,				\
			.ca_owner = THIS_MODULE,			\
	},								\
	.show	= _show,						\
	.store	= _store,						\
}
/* Here is a readonly version, only requiring a show() operation */
#define __CONFIGFS_ATTR_RO(_name, _show)				\
{									\
	.attr	= {							\
			.ca_name = __stringify(_name),			\
			.ca_mode = 0444,				\
			.ca_owner = THIS_MODULE,			\
	},								\
	.show	= _show,						\
}

/*
 * With these extended attributes, the simple show_attribute() and
 * store_attribute() operations need to call the show() and store() of the
 * attributes.  This is a common pattern, so we provide a macro to define
 * them.  The argument _item is the name of the config_item structure.
 * This macro expects the attributes to be named "struct <name>_attribute"
 * and the function to_<name>() to exist;
 */
#define CONFIGFS_ATTR_OPS(_item)					\
static ssize_t _item##_attr_show(struct config_item *item,		\
				 struct configfs_attribute *attr,	\
				 char *page)				\
{									\
	struct _item *_item = to_##_item(item);				\
	struct _item##_attribute *_item##_attr =			\
		container_of(attr, struct _item##_attribute, attr);	\
	ssize_t ret = 0;						\
									\
	if (_item##_attr->show)						\
		ret = _item##_attr->show(_item, page);			\
	return ret;							\
}									\
static ssize_t _item##_attr_store(struct config_item *item,		\
				  struct configfs_attribute *attr,	\
				  const char *page, size_t count)	\
{									\
	struct _item *_item = to_##_item(item);				\
	struct _item##_attribute *_item##_attr =			\
		container_of(attr, struct _item##_attribute, attr);	\
	ssize_t ret = -EINVAL;						\
									\
	if (_item##_attr->store)					\
		ret = _item##_attr->store(_item, page, count);		\
	return ret;							\
}

/*
 * If allow_link() exists, the item can symlink(2) out to other
 * items.  If the item is a group, it may support mkdir(2).
 * Groups supply one of make_group() and make_item().  If the
 * group supports make_group(), one can create group children.  If it
 * supports make_item(), one can create config_item children.  make_group()
 * and make_item() return ERR_PTR() on errors.  If it has
 * default_groups on group->default_groups, it has automatically created
 * group children.  default_groups may coexist alongsize make_group() or
 * make_item(), but if the group wishes to have only default_groups
 * children (disallowing mkdir(2)), it need not provide either function.
 * If the group has commit(), it supports pending and committed (active)
 * items.
 */
struct configfs_item_operations {
	void (*release)(struct config_item *);
	ssize_t	(*show_attribute)(struct config_item *, struct configfs_attribute *,char *);
	ssize_t	(*store_attribute)(struct config_item *,struct configfs_attribute *,const char *, size_t);
	int (*allow_link)(struct config_item *src, struct config_item *target);
	int (*drop_link)(struct config_item *src, struct config_item *target);
};

struct configfs_group_operations {
	struct config_item *(*make_item)(struct config_group *group, const char *name);
	struct config_group *(*make_group)(struct config_group *group, const char *name);
	int (*commit_item)(struct config_item *item);
	void (*disconnect_notify)(struct config_group *group, struct config_item *item);
	void (*drop_item)(struct config_group *group, struct config_item *item);
};

struct configfs_subsystem {
	struct config_group	su_group;
	struct mutex		su_mutex;
};

static inline struct configfs_subsystem *to_configfs_subsystem(struct config_group *group)
{
	return group ?
		container_of(group, struct configfs_subsystem, su_group) :
		NULL;
}

int configfs_register_subsystem(struct configfs_subsystem *subsys);
void configfs_unregister_subsystem(struct configfs_subsystem *subsys);

/* These functions can sleep and can alloc with GFP_KERNEL */
/* WARNING: These cannot be called underneath configfs callbacks!! */
int configfs_depend_item(struct configfs_subsystem *subsys, struct config_item *target);
void configfs_undepend_item(struct configfs_subsystem *subsys, struct config_item *target);

#endif /* _CONFIGFS_H_ */
Commit	Line	Data
7063fbf2 JB	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	*
55dff495 RD	30	* Please read Documentation/filesystems/configfs/configfs.txt before using
55dff495 RD	31	* the configfs interface, ESPECIALLY the parts about reference counts and
7063fbf2 JB	32	* item destructors.
	33	*/
	34
	35	#ifndef _CONFIGFS_H_
	36	#define _CONFIGFS_H_
	37
07783618	38	#include <linux/kernel.h>
7063fbf2 JB	39	#include <linux/types.h>
	40	#include <linux/list.h>
	41	#include <linux/kref.h>
e6bd07ae	42	#include <linux/mutex.h>
dacdd0e0	43	#include <linux/err.h>
7063fbf2	44
60063497	45	#include <linux/atomic.h>
7063fbf2 JB	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_subsystem;
	55
	56	struct config_item {
	57	char *ci_name;
	58	char ci_namebuf[CONFIGFS_ITEM_NAME_LEN];
	59	struct kref ci_kref;
	60	struct list_head ci_entry;
	61	struct config_item *ci_parent;
	62	struct config_group *ci_group;
	63	struct config_item_type *ci_type;
	64	struct dentry *ci_dentry;
	65	};
	66
	67	extern int config_item_set_name(struct config_item , const char , ...);
	68
	69	static inline char config_item_name(struct config_item item)
	70	{
	71	return item->ci_name;
	72	}
	73
	74	extern void config_item_init(struct config_item *);
	75	extern void config_item_init_type_name(struct config_item *item,
	76	const char *name,
	77	struct config_item_type *type);
7063fbf2 JB	78
	79	extern struct config_item * config_item_get(struct config_item *);
	80	extern void config_item_put(struct config_item *);
	81
	82	struct config_item_type {
	83	struct module *ct_owner;
	84	struct configfs_item_operations *ct_item_ops;
	85	struct configfs_group_operations *ct_group_ops;
	86	struct configfs_attribute **ct_attrs;
	87	};
	88
7063fbf2 JB	89	/**
	90	* group - a group of config_items of a specific type, belonging
	91	* to a specific subsystem.
	92	*/
7063fbf2 JB	93	struct config_group {
	94	struct config_item cg_item;
	95	struct list_head cg_children;
	96	struct configfs_subsystem *cg_subsys;
	97	struct config_group **default_groups;
	98	};
	99
7063fbf2 JB	100	extern void config_group_init(struct config_group *group);
	101	extern void config_group_init_type_name(struct config_group *group,
	102	const char *name,
	103	struct config_item_type *type);
	104
7063fbf2 JB	105	static inline struct config_group to_config_group(struct config_item item)
	106	{
	107	return item ? container_of(item,struct config_group,cg_item) : NULL;
	108	}
	109
	110	static inline struct config_group config_group_get(struct config_group group)
	111	{
	112	return group ? to_config_group(config_item_get(&group->cg_item)) : NULL;
	113	}
	114
	115	static inline void config_group_put(struct config_group *group)
	116	{
	117	config_item_put(&group->cg_item);
	118	}
	119
3fe6c5ce SS	120	extern struct config_item config_group_find_item(struct config_group ,
3fe6c5ce SS	121	const char *);
7063fbf2 JB	122
	123
	124	struct configfs_attribute {
3d0f89bb	125	const char *ca_name;
7063fbf2	126	struct module *ca_owner;
43947514	127	umode_t ca_mode;
7063fbf2 JB	128	};
7063fbf2 JB	129
9b1d9aa4 SS	130	/*
	131	* Users often need to create attribute structures for their configurable
	132	* attributes, containing a configfs_attribute member and function pointers
ecb3d28c JB	133	* for the show() and store() operations on that attribute. If they don't
	134	* need anything else on the extended attribute structure, they can use
	135	* this macro to define it The argument _item is the name of the
	136	* config_item structure.
	137	*/
	138	#define CONFIGFS_ATTR_STRUCT(_item) \
	139	struct _item##_attribute { \
	140	struct configfs_attribute attr; \
	141	ssize_t (show)(struct _item , char *); \
	142	ssize_t (store)(struct _item , const char *, size_t); \
	143	}
	144
	145	/*
	146	* With the extended attribute structure, users can use this macro
	147	* (similar to sysfs' __ATTR) to make defining attributes easier.
	148	* An example:
	149	* #define MYITEM_ATTR(_name, _mode, _show, _store) \
	150	* struct myitem_attribute childless_attr_##_name = \
	151	* __CONFIGFS_ATTR(_name, _mode, _show, _store)
9b1d9aa4 SS	152	*/
	153	#define __CONFIGFS_ATTR(_name, _mode, _show, _store) \
	154	{ \
	155	.attr = { \
	156	.ca_name = __stringify(_name), \
	157	.ca_mode = _mode, \
	158	.ca_owner = THIS_MODULE, \
	159	}, \
	160	.show = _show, \
	161	.store = _store, \
	162	}
ecb3d28c JB	163	/* Here is a readonly version, only requiring a show() operation */
	164	#define __CONFIGFS_ATTR_RO(_name, _show) \
	165	{ \
	166	.attr = { \
	167	.ca_name = __stringify(_name), \
	168	.ca_mode = 0444, \
	169	.ca_owner = THIS_MODULE, \
	170	}, \
	171	.show = _show, \
	172	}
	173
	174	/*
	175	* With these extended attributes, the simple show_attribute() and
	176	* store_attribute() operations need to call the show() and store() of the
	177	* attributes. This is a common pattern, so we provide a macro to define
	178	* them. The argument _item is the name of the config_item structure.
	179	* This macro expects the attributes to be named "struct <name>_attribute"
	180	* and the function to_<name>() to exist;
	181	*/
	182	#define CONFIGFS_ATTR_OPS(_item) \
	183	static ssize_t _item##_attr_show(struct config_item *item, \
	184	struct configfs_attribute *attr, \
	185	char *page) \
	186	{ \
	187	struct _item *_item = to_##_item(item); \
	188	struct _item##_attribute *_item##_attr = \
	189	container_of(attr, struct _item##_attribute, attr); \
	190	ssize_t ret = 0; \
	191	\
	192	if (_item##_attr->show) \
	193	ret = _item##_attr->show(_item, page); \
	194	return ret; \
	195	} \
	196	static ssize_t _item##_attr_store(struct config_item *item, \
	197	struct configfs_attribute *attr, \
	198	const char *page, size_t count) \
	199	{ \
	200	struct _item *_item = to_##_item(item); \
	201	struct _item##_attribute *_item##_attr = \
	202	container_of(attr, struct _item##_attribute, attr); \
	203	ssize_t ret = -EINVAL; \
	204	\
	205	if (_item##_attr->store) \
	206	ret = _item##_attr->store(_item, page, count); \
	207	return ret; \
	208	}
7063fbf2 JB	209
	210	/*
	211	* If allow_link() exists, the item can symlink(2) out to other
	212	* items. If the item is a group, it may support mkdir(2).
	213	* Groups supply one of make_group() and make_item(). If the
	214	* group supports make_group(), one can create group children. If it
a6795e9e JB	215	* supports make_item(), one can create config_item children. make_group()
a6795e9e JB	216	* and make_item() return ERR_PTR() on errors. If it has
7063fbf2 JB	217	* default_groups on group->default_groups, it has automatically created
	218	* group children. default_groups may coexist alongsize make_group() or
	219	* make_item(), but if the group wishes to have only default_groups
	220	* children (disallowing mkdir(2)), it need not provide either function.
25985edc	221	* If the group has commit(), it supports pending and committed (active)
7063fbf2 JB	222	* items.
	223	*/
	224	struct configfs_item_operations {
	225	void (release)(struct config_item );
	226	ssize_t (show_attribute)(struct config_item , struct configfs_attribute ,char );
	227	ssize_t (store_attribute)(struct config_item ,struct configfs_attribute ,const char , size_t);
	228	int (allow_link)(struct config_item src, struct config_item *target);
	229	int (drop_link)(struct config_item src, struct config_item *target);
	230	};
	231
	232	struct configfs_group_operations {
f89ab861 JB	233	struct config_item (make_item)(struct config_group group, const char name);
f89ab861 JB	234	struct config_group (make_group)(struct config_group group, const char name);
7063fbf2	235	int (commit_item)(struct config_item item);
299894cc	236	void (disconnect_notify)(struct config_group group, struct config_item *item);
7063fbf2 JB	237	void (drop_item)(struct config_group group, struct config_item *item);
	238	};
	239
7063fbf2 JB	240	struct configfs_subsystem {
7063fbf2 JB	241	struct config_group su_group;
e6bd07ae	242	struct mutex su_mutex;
7063fbf2 JB	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
631d1feb JB	255	/* These functions can sleep and can alloc with GFP_KERNEL */
	256	/* WARNING: These cannot be called underneath configfs callbacks!! */
	257	int configfs_depend_item(struct configfs_subsystem subsys, struct config_item target);
	258	void configfs_undepend_item(struct configfs_subsystem subsys, struct config_item target);
	259
7063fbf2	260	#endif /* _CONFIGFS_H_ */