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1/* -*- mode: c; c-basic-offset: 8; -*-
2 * vim: noexpandtab sw=8 ts=8 sts=0:
3 *
4 * configfs_macros.h - extends macros for configfs
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 * Added CONFIGFS_EATTR() macros from original configfs.h macros
31 * Copright (C) 2008-2009 Nicholas A. Bellinger <nab@linux-iscsi.org>
32 *
33 * Please read Documentation/filesystems/configfs/configfs.txt before using
34 * the configfs interface, ESPECIALLY the parts about reference counts and
35 * item destructors.
36 */
37
38#ifndef _CONFIGFS_MACROS_H_
39#define _CONFIGFS_MACROS_H_
40
41#include <linux/configfs.h>
42
43/*
44 * Users often need to create attribute structures for their configurable
45 * attributes, containing a configfs_attribute member and function pointers
46 * for the show() and store() operations on that attribute. If they don't
47 * need anything else on the extended attribute structure, they can use
48 * this macro to define it. The argument _name isends up as
49 * 'struct _name_attribute, as well as names of to CONFIGFS_ATTR_OPS() below.
50 * The argument _item is the name of the structure containing the
51 * struct config_item or struct config_group structure members
52 */
53#define CONFIGFS_EATTR_STRUCT(_name, _item) \
54struct _name##_attribute { \
55 struct configfs_attribute attr; \
56 ssize_t (*show)(struct _item *, char *); \
57 ssize_t (*store)(struct _item *, const char *, size_t); \
58}
59
60/*
61 * With the extended attribute structure, users can use this macro
62 * (similar to sysfs' __ATTR) to make defining attributes easier.
63 * An example:
64 * #define MYITEM_EATTR(_name, _mode, _show, _store) \
65 * struct myitem_attribute childless_attr_##_name = \
66 * __CONFIGFS_EATTR(_name, _mode, _show, _store)
67 */
68#define __CONFIGFS_EATTR(_name, _mode, _show, _store) \
69{ \
70 .attr = { \
71 .ca_name = __stringify(_name), \
72 .ca_mode = _mode, \
73 .ca_owner = THIS_MODULE, \
74 }, \
75 .show = _show, \
76 .store = _store, \
77}
78/* Here is a readonly version, only requiring a show() operation */
79#define __CONFIGFS_EATTR_RO(_name, _show) \
80{ \
81 .attr = { \
82 .ca_name = __stringify(_name), \
83 .ca_mode = 0444, \
84 .ca_owner = THIS_MODULE, \
85 }, \
86 .show = _show, \
87}
88
89/*
90 * With these extended attributes, the simple show_attribute() and
91 * store_attribute() operations need to call the show() and store() of the
92 * attributes. This is a common pattern, so we provide a macro to define
93 * them. The argument _name is the name of the attribute defined by
94 * CONFIGFS_ATTR_STRUCT(). The argument _item is the name of the structure
95 * containing the struct config_item or struct config_group structure member.
96 * The argument _item_member is the actual name of the struct config_* struct
97 * in your _item structure. Meaning my_structure->some_config_group.
98 * ^^_item^^^^^ ^^_item_member^^^
99 * This macro expects the attributes to be named "struct <name>_attribute".
100 */
101#define CONFIGFS_EATTR_OPS_TO_FUNC(_name, _item, _item_member) \
102static struct _item *to_##_name(struct config_item *ci) \
103{ \
104 return (ci) ? container_of(to_config_group(ci), struct _item, \
105 _item_member) : NULL; \
106}
107
108#define CONFIGFS_EATTR_OPS_SHOW(_name, _item) \
109static ssize_t _name##_attr_show(struct config_item *item, \
110 struct configfs_attribute *attr, \
111 char *page) \
112{ \
113 struct _item *_item = to_##_name(item); \
114 struct _name##_attribute * _name##_attr = \
115 container_of(attr, struct _name##_attribute, attr); \
116 ssize_t ret = 0; \
117 \
118 if (_name##_attr->show) \
119 ret = _name##_attr->show(_item, page); \
120 return ret; \
121}
122
123#define CONFIGFS_EATTR_OPS_STORE(_name, _item) \
124static ssize_t _name##_attr_store(struct config_item *item, \
125 struct configfs_attribute *attr, \
126 const char *page, size_t count) \
127{ \
128 struct _item *_item = to_##_name(item); \
129 struct _name##_attribute * _name##_attr = \
130 container_of(attr, struct _name##_attribute, attr); \
131 ssize_t ret = -EINVAL; \
132 \
133 if (_name##_attr->store) \
134 ret = _name##_attr->store(_item, page, count); \
135 return ret; \
136}
137
138#define CONFIGFS_EATTR_OPS(_name, _item, _item_member) \
139 CONFIGFS_EATTR_OPS_TO_FUNC(_name, _item, _item_member); \
140 CONFIGFS_EATTR_OPS_SHOW(_name, _item); \
141 CONFIGFS_EATTR_OPS_STORE(_name, _item);
142
143#define CONFIGFS_EATTR_OPS_RO(_name, _item, _item_member) \
144 CONFIGFS_EATTR_OPS_TO_FUNC(_name, _item, _item_member); \
145 CONFIGFS_EATTR_OPS_SHOW(_name, _item);
146
147#endif /* _CONFIGFS_MACROS_H_ */