linux/include/target/configfs_macros.h
<<
>>
Prefs
   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
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.