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authorChristoph Hellwig <hch@lst.de>2015-10-03 15:32:59 +0200
committerNicholas Bellinger <nab@linux-iscsi.org>2015-10-13 22:17:57 -0700
commit517982229f78b2aebf00a8a337e84e8eeea70b8e (patch)
tree6f5f093837a26d5b56874689234dc818951779ac /samples/configfs/configfs_sample.c
parent45b997737a8025be2825e464e9e9dd5d07160dc3 (diff)
downloadlinux-517982229f78b2aebf00a8a337e84e8eeea70b8e.tar.gz
configfs: remove old API
Remove the old show_attribute and store_attribute methods and update the documentation. Also replace the two C samples with a single new one in the proper samples directory where people expect to find it. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Diffstat (limited to 'samples/configfs/configfs_sample.c')
-rw-r--r--samples/configfs/configfs_sample.c404
1 files changed, 404 insertions, 0 deletions
diff --git a/samples/configfs/configfs_sample.c b/samples/configfs/configfs_sample.c
new file mode 100644
index 000000000000..1ea33119e532
--- /dev/null
+++ b/samples/configfs/configfs_sample.c
@@ -0,0 +1,404 @@
+/*
+ * vim: noexpandtab ts=8 sts=0 sw=8:
+ *
+ * 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
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ *
+ * 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/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 item ? container_of(to_configfs_subsystem(to_config_group(item)),
+ struct childless, subsys) : NULL;
+}
+
+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);
+ unsigned long tmp;
+ char *p = (char *) page;
+
+ tmp = simple_strtoul(p, &p, 10);
+ if (!p || (*p && (*p != '\n')))
+ return -EINVAL;
+
+ if (tmp > INT_MAX)
+ return -ERANGE;
+
+ childless->storeme = tmp;
+
+ 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 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 item ? container_of(item, struct simple_child, item) : NULL;
+}
+
+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);
+ unsigned long tmp;
+ char *p = (char *) page;
+
+ tmp = simple_strtoul(p, &p, 10);
+ if (!p || (*p && (*p != '\n')))
+ return -EINVAL;
+
+ if (tmp > INT_MAX)
+ return -ERANGE;
+
+ simple_child->storeme = tmp;
+
+ 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 struct configfs_item_operations simple_child_item_ops = {
+ .release = simple_child_release,
+};
+
+static 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 item ? container_of(to_config_group(item),
+ struct simple_children, group) : NULL;
+}
+
+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);
+
+ simple_child->storeme = 0;
+
+ 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 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 struct configfs_group_operations simple_children_group_ops = {
+ .make_item = simple_children_make_item,
+};
+
+static 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 struct configfs_group_operations group_children_group_ops = {
+ .make_group = group_children_make_group,
+};
+
+static 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)
+{
+ int ret;
+ int i;
+ struct configfs_subsystem *subsys;
+
+ 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) {
+ printk(KERN_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_LICENSE("GPL");