configfs_macros.h
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/* -*- mode: c; c-basic-offset: 8; -*-
* vim: noexpandtab sw=8 ts=8 sts=0:
*
* configfs_macros.h - extends macros for configfs
*
* 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.
*
* Added CONFIGFS_EATTR() macros from original configfs.h macros
* Copright (C) 2008-2009 Nicholas A. Bellinger <nab@linux-iscsi.org>
*
* Please read Documentation/filesystems/configfs/configfs.txt before using
* the configfs interface, ESPECIALLY the parts about reference counts and
* item destructors.
*/
#ifndef _CONFIGFS_MACROS_H_
#define _CONFIGFS_MACROS_H_
#include <linux/configfs.h>
/*
* 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 _name isends up as
* 'struct _name_attribute, as well as names of to CONFIGFS_ATTR_OPS() below.
* The argument _item is the name of the structure containing the
* struct config_item or struct config_group structure members
*/
#define CONFIGFS_EATTR_STRUCT(_name, _item) \
struct _name##_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_EATTR(_name, _mode, _show, _store) \
* struct myitem_attribute childless_attr_##_name = \
* __CONFIGFS_EATTR(_name, _mode, _show, _store)
*/
#define __CONFIGFS_EATTR(_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_EATTR_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 _name is the name of the attribute defined by
* CONFIGFS_ATTR_STRUCT(). The argument _item is the name of the structure
* containing the struct config_item or struct config_group structure member.
* The argument _item_member is the actual name of the struct config_* struct
* in your _item structure. Meaning my_structure->some_config_group.
* ^^_item^^^^^ ^^_item_member^^^
* This macro expects the attributes to be named "struct <name>_attribute".
*/
#define CONFIGFS_EATTR_OPS_TO_FUNC(_name, _item, _item_member) \
static struct _item *to_##_name(struct config_item *ci) \
{ \
return (ci) ? container_of(to_config_group(ci), struct _item, \
_item_member) : NULL; \
}
#define CONFIGFS_EATTR_OPS_SHOW(_name, _item) \
static ssize_t _name##_attr_show(struct config_item *item, \
struct configfs_attribute *attr, \
char *page) \
{ \
struct _item *_item = to_##_name(item); \
struct _name##_attribute * _name##_attr = \
container_of(attr, struct _name##_attribute, attr); \
ssize_t ret = 0; \
\
if (_name##_attr->show) \
ret = _name##_attr->show(_item, page); \
return ret; \
}
#define CONFIGFS_EATTR_OPS_STORE(_name, _item) \
static ssize_t _name##_attr_store(struct config_item *item, \
struct configfs_attribute *attr, \
const char *page, size_t count) \
{ \
struct _item *_item = to_##_name(item); \
struct _name##_attribute * _name##_attr = \
container_of(attr, struct _name##_attribute, attr); \
ssize_t ret = -EINVAL; \
\
if (_name##_attr->store) \
ret = _name##_attr->store(_item, page, count); \
return ret; \
}
#define CONFIGFS_EATTR_OPS(_name, _item, _item_member) \
CONFIGFS_EATTR_OPS_TO_FUNC(_name, _item, _item_member); \
CONFIGFS_EATTR_OPS_SHOW(_name, _item); \
CONFIGFS_EATTR_OPS_STORE(_name, _item);
#define CONFIGFS_EATTR_OPS_RO(_name, _item, _item_member) \
CONFIGFS_EATTR_OPS_TO_FUNC(_name, _item, _item_member); \
CONFIGFS_EATTR_OPS_SHOW(_name, _item);
#endif /* _CONFIGFS_MACROS_H_ */