mirror of https://gitee.com/openkylin/linux.git
405 lines
9.9 KiB
C
405 lines
9.9 KiB
C
/*
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* vim: noexpandtab ts=8 sts=0 sw=8:
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*
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* configfs_example_macros.c - This file is a demonstration module
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* containing a number of configfs subsystems. It uses the helper
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* macros defined by configfs.h
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*
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* Based on sysfs:
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* sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
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*
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* configfs Copyright (C) 2005 Oracle. All rights reserved.
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/configfs.h>
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/*
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* 01-childless
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*
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* This first example is a childless subsystem. It cannot create
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* any config_items. It just has attributes.
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*
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* Note that we are enclosing the configfs_subsystem inside a container.
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* This is not necessary if a subsystem has no attributes directly
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* on the subsystem. See the next example, 02-simple-children, for
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* such a subsystem.
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*/
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struct childless {
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struct configfs_subsystem subsys;
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int showme;
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int storeme;
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};
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static inline struct childless *to_childless(struct config_item *item)
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{
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return item ? container_of(to_configfs_subsystem(to_config_group(item)),
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struct childless, subsys) : NULL;
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}
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static ssize_t childless_showme_show(struct config_item *item, char *page)
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{
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struct childless *childless = to_childless(item);
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ssize_t pos;
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pos = sprintf(page, "%d\n", childless->showme);
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childless->showme++;
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return pos;
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}
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static ssize_t childless_storeme_show(struct config_item *item, char *page)
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{
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return sprintf(page, "%d\n", to_childless(item)->storeme);
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}
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static ssize_t childless_storeme_store(struct config_item *item,
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const char *page, size_t count)
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{
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struct childless *childless = to_childless(item);
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unsigned long tmp;
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char *p = (char *) page;
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tmp = simple_strtoul(p, &p, 10);
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if (!p || (*p && (*p != '\n')))
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return -EINVAL;
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if (tmp > INT_MAX)
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return -ERANGE;
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childless->storeme = tmp;
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return count;
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}
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static ssize_t childless_description_show(struct config_item *item, char *page)
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{
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return sprintf(page,
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"[01-childless]\n"
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"\n"
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"The childless subsystem is the simplest possible subsystem in\n"
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"configfs. It does not support the creation of child config_items.\n"
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"It only has a few attributes. In fact, it isn't much different\n"
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"than a directory in /proc.\n");
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}
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CONFIGFS_ATTR_RO(childless_, showme);
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CONFIGFS_ATTR(childless_, storeme);
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CONFIGFS_ATTR_RO(childless_, description);
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static struct configfs_attribute *childless_attrs[] = {
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&childless_attr_showme,
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&childless_attr_storeme,
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&childless_attr_description,
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NULL,
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};
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static const struct config_item_type childless_type = {
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.ct_attrs = childless_attrs,
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.ct_owner = THIS_MODULE,
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};
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static struct childless childless_subsys = {
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.subsys = {
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.su_group = {
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.cg_item = {
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.ci_namebuf = "01-childless",
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.ci_type = &childless_type,
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},
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},
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},
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};
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/* ----------------------------------------------------------------- */
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/*
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* 02-simple-children
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*
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* This example merely has a simple one-attribute child. Note that
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* there is no extra attribute structure, as the child's attribute is
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* known from the get-go. Also, there is no container for the
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* subsystem, as it has no attributes of its own.
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*/
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struct simple_child {
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struct config_item item;
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int storeme;
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};
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static inline struct simple_child *to_simple_child(struct config_item *item)
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{
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return item ? container_of(item, struct simple_child, item) : NULL;
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}
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static ssize_t simple_child_storeme_show(struct config_item *item, char *page)
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{
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return sprintf(page, "%d\n", to_simple_child(item)->storeme);
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}
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static ssize_t simple_child_storeme_store(struct config_item *item,
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const char *page, size_t count)
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{
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struct simple_child *simple_child = to_simple_child(item);
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unsigned long tmp;
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char *p = (char *) page;
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tmp = simple_strtoul(p, &p, 10);
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if (!p || (*p && (*p != '\n')))
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return -EINVAL;
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if (tmp > INT_MAX)
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return -ERANGE;
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simple_child->storeme = tmp;
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return count;
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}
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CONFIGFS_ATTR(simple_child_, storeme);
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static struct configfs_attribute *simple_child_attrs[] = {
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&simple_child_attr_storeme,
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NULL,
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};
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static void simple_child_release(struct config_item *item)
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{
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kfree(to_simple_child(item));
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}
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static struct configfs_item_operations simple_child_item_ops = {
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.release = simple_child_release,
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};
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static const struct config_item_type simple_child_type = {
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.ct_item_ops = &simple_child_item_ops,
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.ct_attrs = simple_child_attrs,
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.ct_owner = THIS_MODULE,
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};
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struct simple_children {
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struct config_group group;
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};
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static inline struct simple_children *to_simple_children(struct config_item *item)
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{
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return item ? container_of(to_config_group(item),
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struct simple_children, group) : NULL;
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}
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static struct config_item *simple_children_make_item(struct config_group *group,
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const char *name)
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{
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struct simple_child *simple_child;
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simple_child = kzalloc(sizeof(struct simple_child), GFP_KERNEL);
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if (!simple_child)
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return ERR_PTR(-ENOMEM);
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config_item_init_type_name(&simple_child->item, name,
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&simple_child_type);
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simple_child->storeme = 0;
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return &simple_child->item;
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}
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static ssize_t simple_children_description_show(struct config_item *item,
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char *page)
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{
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return sprintf(page,
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"[02-simple-children]\n"
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"\n"
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"This subsystem allows the creation of child config_items. These\n"
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"items have only one attribute that is readable and writeable.\n");
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}
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CONFIGFS_ATTR_RO(simple_children_, description);
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static struct configfs_attribute *simple_children_attrs[] = {
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&simple_children_attr_description,
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NULL,
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};
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static void simple_children_release(struct config_item *item)
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{
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kfree(to_simple_children(item));
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}
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static struct configfs_item_operations simple_children_item_ops = {
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.release = simple_children_release,
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};
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/*
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* Note that, since no extra work is required on ->drop_item(),
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* no ->drop_item() is provided.
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*/
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static struct configfs_group_operations simple_children_group_ops = {
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.make_item = simple_children_make_item,
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};
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static const struct config_item_type simple_children_type = {
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.ct_item_ops = &simple_children_item_ops,
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.ct_group_ops = &simple_children_group_ops,
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.ct_attrs = simple_children_attrs,
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.ct_owner = THIS_MODULE,
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};
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static struct configfs_subsystem simple_children_subsys = {
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.su_group = {
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.cg_item = {
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.ci_namebuf = "02-simple-children",
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.ci_type = &simple_children_type,
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},
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},
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};
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/* ----------------------------------------------------------------- */
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/*
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* 03-group-children
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*
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* This example reuses the simple_children group from above. However,
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* the simple_children group is not the subsystem itself, it is a
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* child of the subsystem. Creation of a group in the subsystem creates
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* a new simple_children group. That group can then have simple_child
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* children of its own.
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*/
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static struct config_group *group_children_make_group(
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struct config_group *group, const char *name)
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{
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struct simple_children *simple_children;
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simple_children = kzalloc(sizeof(struct simple_children),
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GFP_KERNEL);
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if (!simple_children)
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return ERR_PTR(-ENOMEM);
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config_group_init_type_name(&simple_children->group, name,
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&simple_children_type);
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return &simple_children->group;
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}
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static ssize_t group_children_description_show(struct config_item *item,
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char *page)
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{
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return sprintf(page,
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"[03-group-children]\n"
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"\n"
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"This subsystem allows the creation of child config_groups. These\n"
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"groups are like the subsystem simple-children.\n");
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}
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CONFIGFS_ATTR_RO(group_children_, description);
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static struct configfs_attribute *group_children_attrs[] = {
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&group_children_attr_description,
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NULL,
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};
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/*
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* Note that, since no extra work is required on ->drop_item(),
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* no ->drop_item() is provided.
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*/
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static struct configfs_group_operations group_children_group_ops = {
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.make_group = group_children_make_group,
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};
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static const struct config_item_type group_children_type = {
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.ct_group_ops = &group_children_group_ops,
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.ct_attrs = group_children_attrs,
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.ct_owner = THIS_MODULE,
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};
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static struct configfs_subsystem group_children_subsys = {
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.su_group = {
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.cg_item = {
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.ci_namebuf = "03-group-children",
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.ci_type = &group_children_type,
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},
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},
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};
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/* ----------------------------------------------------------------- */
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/*
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* We're now done with our subsystem definitions.
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* For convenience in this module, here's a list of them all. It
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* allows the init function to easily register them. Most modules
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* will only have one subsystem, and will only call register_subsystem
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* on it directly.
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*/
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static struct configfs_subsystem *example_subsys[] = {
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&childless_subsys.subsys,
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&simple_children_subsys,
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&group_children_subsys,
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NULL,
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};
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static int __init configfs_example_init(void)
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{
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int ret;
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int i;
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struct configfs_subsystem *subsys;
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for (i = 0; example_subsys[i]; i++) {
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subsys = example_subsys[i];
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config_group_init(&subsys->su_group);
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mutex_init(&subsys->su_mutex);
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ret = configfs_register_subsystem(subsys);
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if (ret) {
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printk(KERN_ERR "Error %d while registering subsystem %s\n",
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ret,
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subsys->su_group.cg_item.ci_namebuf);
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goto out_unregister;
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}
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}
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return 0;
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out_unregister:
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for (i--; i >= 0; i--)
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configfs_unregister_subsystem(example_subsys[i]);
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return ret;
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}
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static void __exit configfs_example_exit(void)
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{
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int i;
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for (i = 0; example_subsys[i]; i++)
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configfs_unregister_subsystem(example_subsys[i]);
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}
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module_init(configfs_example_init);
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module_exit(configfs_example_exit);
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MODULE_LICENSE("GPL");
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