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_ */ 148