// SPDX-License-Identifier: GPL-2.0-or-later/* * configfs_example_macros.c - This file is a demonstration module *      containing a number of configfs subsystems.  It uses the helper *      macros defined by configfs.h * * Based on sysfs: *      sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel * * configfs Copyright (C) 2005 Oracle.  All rights reserved. */ #include <linux/init.h>#include <linux/kernel.h>#include <linux/module.h>#include <linux/slab.h>#include <linux/configfs.h> /* * 01-childless * * This first example is a childless subsystem.  It cannot create * any config_items.  It just has attributes. * * Note that we are enclosing the configfs_subsystem inside a container. * This is not necessary if a subsystem has no attributes directly * on the subsystem.  See the next example, 02-simple-children, for * such a subsystem. */ struct childless {	struct configfs_subsystem subsys;	int showme;	int storeme;}; static inline struct childless *to_childless(struct config_item *item){	return container_of(to_configfs_subsystem(to_config_group(item)),			    struct childless, subsys);} static ssize_t childless_showme_show(struct config_item *item, char *page){	struct childless *childless = to_childless(item);	ssize_t pos; 	pos = sprintf(page, "%d\n", childless->showme);	childless->showme++; 	return pos;} static ssize_t childless_storeme_show(struct config_item *item, char *page){	return sprintf(page, "%d\n", to_childless(item)->storeme);} static ssize_t childless_storeme_store(struct config_item *item,		const char *page, size_t count){	struct childless *childless = to_childless(item);	int ret; 	ret = kstrtoint(page, 10, &childless->storeme);	if (ret)		return ret; 	return count;} static ssize_t childless_description_show(struct config_item *item, char *page){	return sprintf(page,"[01-childless]\n""\n""The childless subsystem is the simplest possible subsystem in\n""configfs.  It does not support the creation of child config_items.\n""It only has a few attributes.  In fact, it isn't much different\n""than a directory in /proc.\n");} CONFIGFS_ATTR_RO(childless_, showme);CONFIGFS_ATTR(childless_, storeme);CONFIGFS_ATTR_RO(childless_, description); static struct configfs_attribute *childless_attrs[] = {	&childless_attr_showme,	&childless_attr_storeme,	&childless_attr_description,	NULL,}; static const struct config_item_type childless_type = {	.ct_attrs	= childless_attrs,	.ct_owner	= THIS_MODULE,}; static struct childless childless_subsys = {	.subsys = {		.su_group = {			.cg_item = {				.ci_namebuf = "01-childless",				.ci_type = &childless_type,			},		},	},}; /* ----------------------------------------------------------------- */ /* * 02-simple-children * * This example merely has a simple one-attribute child.  Note that * there is no extra attribute structure, as the child's attribute is * known from the get-go.  Also, there is no container for the * subsystem, as it has no attributes of its own. */ struct simple_child {	struct config_item item;	int storeme;}; static inline struct simple_child *to_simple_child(struct config_item *item){	return container_of(item, struct simple_child, item);} static ssize_t simple_child_storeme_show(struct config_item *item, char *page){	return sprintf(page, "%d\n", to_simple_child(item)->storeme);} static ssize_t simple_child_storeme_store(struct config_item *item,		const char *page, size_t count){	struct simple_child *simple_child = to_simple_child(item);	int ret; 	ret = kstrtoint(page, 10, &simple_child->storeme);	if (ret)		return ret; 	return count;} CONFIGFS_ATTR(simple_child_, storeme); static struct configfs_attribute *simple_child_attrs[] = {	&simple_child_attr_storeme,	NULL,}; static void simple_child_release(struct config_item *item){	kfree(to_simple_child(item));} static const struct configfs_item_operations simple_child_item_ops = {	.release	= simple_child_release,}; static const struct config_item_type simple_child_type = {	.ct_item_ops	= &simple_child_item_ops,	.ct_attrs	= simple_child_attrs,	.ct_owner	= THIS_MODULE,}; struct simple_children {	struct config_group group;}; static inline struct simple_children *to_simple_children(struct config_item *item){	return container_of(to_config_group(item),			    struct simple_children, group);} static struct config_item *simple_children_make_item(struct config_group *group,		const char *name){	struct simple_child *simple_child; 	simple_child = kzalloc(sizeof(struct simple_child), GFP_KERNEL);	if (!simple_child)		return ERR_PTR(-ENOMEM); 	config_item_init_type_name(&simple_child->item, name,				   &simple_child_type); 	return &simple_child->item;} static ssize_t simple_children_description_show(struct config_item *item,		char *page){	return sprintf(page,"[02-simple-children]\n""\n""This subsystem allows the creation of child config_items.  These\n""items have only one attribute that is readable and writeable.\n");} CONFIGFS_ATTR_RO(simple_children_, description); static struct configfs_attribute *simple_children_attrs[] = {	&simple_children_attr_description,	NULL,}; static void simple_children_release(struct config_item *item){	kfree(to_simple_children(item));} static const struct configfs_item_operations simple_children_item_ops = {	.release	= simple_children_release,}; /* * Note that, since no extra work is required on ->drop_item(), * no ->drop_item() is provided. */static const struct configfs_group_operations simple_children_group_ops = {	.make_item	= simple_children_make_item,}; static const struct config_item_type simple_children_type = {	.ct_item_ops	= &simple_children_item_ops,	.ct_group_ops	= &simple_children_group_ops,	.ct_attrs	= simple_children_attrs,	.ct_owner	= THIS_MODULE,}; static struct configfs_subsystem simple_children_subsys = {	.su_group = {		.cg_item = {			.ci_namebuf = "02-simple-children",			.ci_type = &simple_children_type,		},	},}; /* ----------------------------------------------------------------- */ /* * 03-group-children * * This example reuses the simple_children group from above.  However, * the simple_children group is not the subsystem itself, it is a * child of the subsystem.  Creation of a group in the subsystem creates * a new simple_children group.  That group can then have simple_child * children of its own. */ static struct config_group *group_children_make_group(		struct config_group *group, const char *name){	struct simple_children *simple_children; 	simple_children = kzalloc(sizeof(struct simple_children),				  GFP_KERNEL);	if (!simple_children)		return ERR_PTR(-ENOMEM); 	config_group_init_type_name(&simple_children->group, name,				    &simple_children_type); 	return &simple_children->group;} static ssize_t group_children_description_show(struct config_item *item,		char *page){	return sprintf(page,"[03-group-children]\n""\n""This subsystem allows the creation of child config_groups.  These\n""groups are like the subsystem simple-children.\n");} CONFIGFS_ATTR_RO(group_children_, description); static struct configfs_attribute *group_children_attrs[] = {	&group_children_attr_description,	NULL,}; /* * Note that, since no extra work is required on ->drop_item(), * no ->drop_item() is provided. */static const struct configfs_group_operations group_children_group_ops = {	.make_group	= group_children_make_group,}; static const struct config_item_type group_children_type = {	.ct_group_ops	= &group_children_group_ops,	.ct_attrs	= group_children_attrs,	.ct_owner	= THIS_MODULE,}; static struct configfs_subsystem group_children_subsys = {	.su_group = {		.cg_item = {			.ci_namebuf = "03-group-children",			.ci_type = &group_children_type,		},	},}; /* ----------------------------------------------------------------- */ /* * We're now done with our subsystem definitions. * For convenience in this module, here's a list of them all.  It * allows the init function to easily register them.  Most modules * will only have one subsystem, and will only call register_subsystem * on it directly. */static struct configfs_subsystem *example_subsys[] = {	&childless_subsys.subsys,	&simple_children_subsys,	&group_children_subsys,	NULL,}; static int __init configfs_example_init(void){	struct configfs_subsystem *subsys;	int ret, i; 	for (i = 0; example_subsys[i]; i++) {		subsys = example_subsys[i]; 		config_group_init(&subsys->su_group);		mutex_init(&subsys->su_mutex);		ret = configfs_register_subsystem(subsys);		if (ret) {			pr_err("Error %d while registering subsystem %s\n",			       ret, subsys->su_group.cg_item.ci_namebuf);			goto out_unregister;		}	} 	return 0; out_unregister:	for (i--; i >= 0; i--)		configfs_unregister_subsystem(example_subsys[i]); 	return ret;} static void __exit configfs_example_exit(void){	int i; 	for (i = 0; example_subsys[i]; i++)		configfs_unregister_subsystem(example_subsys[i]);} module_init(configfs_example_init);module_exit(configfs_example_exit);MODULE_DESCRIPTION("Sample configfs module");MODULE_LICENSE("GPL");