Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1098 insertions, 0 deletions

diff --git a/lib/kobject.c b/lib/kobject.c
new file mode 100644
index 000000000..97d86dc17
--- /dev/null
+++ b/lib/kobject.c
@@ -0,0 +1,1098 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * kobject.c - library routines for handling generic kernel objects
+ *
+ * Copyright (c) 2002-2003 Patrick Mochel <mochel@osdl.org>
+ * Copyright (c) 2006-2007 Greg Kroah-Hartman <greg@kroah.com>
+ * Copyright (c) 2006-2007 Novell Inc.
+ *
+ * Please see the file Documentation/kobject.txt for critical information
+ * about using the kobject interface.
+ */
+
+#include <linux/kobject.h>
+#include <linux/string.h>
+#include <linux/export.h>
+#include <linux/stat.h>
+#include <linux/slab.h>
+#include <linux/random.h>
+
+/**
+ * kobject_namespace - return @kobj's namespace tag
+ * @kobj: kobject in question
+ *
+ * Returns namespace tag of @kobj if its parent has namespace ops enabled
+ * and thus @kobj should have a namespace tag associated with it.  Returns
+ * %NULL otherwise.
+ */
+const void *kobject_namespace(struct kobject *kobj)
+{
+	const struct kobj_ns_type_operations *ns_ops = kobj_ns_ops(kobj);
+
+	if (!ns_ops || ns_ops->type == KOBJ_NS_TYPE_NONE)
+		return NULL;
+
+	return kobj->ktype->namespace(kobj);
+}
+
+/**
+ * kobject_get_ownership - get sysfs ownership data for @kobj
+ * @kobj: kobject in question
+ * @uid: kernel user ID for sysfs objects
+ * @gid: kernel group ID for sysfs objects
+ *
+ * Returns initial uid/gid pair that should be used when creating sysfs
+ * representation of given kobject. Normally used to adjust ownership of
+ * objects in a container.
+ */
+void kobject_get_ownership(struct kobject *kobj, kuid_t *uid, kgid_t *gid)
+{
+	*uid = GLOBAL_ROOT_UID;
+	*gid = GLOBAL_ROOT_GID;
+
+	if (kobj->ktype->get_ownership)
+		kobj->ktype->get_ownership(kobj, uid, gid);
+}
+
+/*
+ * populate_dir - populate directory with attributes.
+ * @kobj: object we're working on.
+ *
+ * Most subsystems have a set of default attributes that are associated
+ * with an object that registers with them.  This is a helper called during
+ * object registration that loops through the default attributes of the
+ * subsystem and creates attributes files for them in sysfs.
+ */
+static int populate_dir(struct kobject *kobj)
+{
+	struct kobj_type *t = get_ktype(kobj);
+	struct attribute *attr;
+	int error = 0;
+	int i;
+
+	if (t && t->default_attrs) {
+		for (i = 0; (attr = t->default_attrs[i]) != NULL; i++) {
+			error = sysfs_create_file(kobj, attr);
+			if (error)
+				break;
+		}
+	}
+	return error;
+}
+
+static int create_dir(struct kobject *kobj)
+{
+	const struct kobj_ns_type_operations *ops;
+	int error;
+
+	error = sysfs_create_dir_ns(kobj, kobject_namespace(kobj));
+	if (error)
+		return error;
+
+	error = populate_dir(kobj);
+	if (error) {
+		sysfs_remove_dir(kobj);
+		return error;
+	}
+
+	/*
+	 * @kobj->sd may be deleted by an ancestor going away.  Hold an
+	 * extra reference so that it stays until @kobj is gone.
+	 */
+	sysfs_get(kobj->sd);
+
+	/*
+	 * If @kobj has ns_ops, its children need to be filtered based on
+	 * their namespace tags.  Enable namespace support on @kobj->sd.
+	 */
+	ops = kobj_child_ns_ops(kobj);
+	if (ops) {
+		BUG_ON(ops->type <= KOBJ_NS_TYPE_NONE);
+		BUG_ON(ops->type >= KOBJ_NS_TYPES);
+		BUG_ON(!kobj_ns_type_registered(ops->type));
+
+		sysfs_enable_ns(kobj->sd);
+	}
+
+	return 0;
+}
+
+static int get_kobj_path_length(struct kobject *kobj)
+{
+	int length = 1;
+	struct kobject *parent = kobj;
+
+	/* walk up the ancestors until we hit the one pointing to the
+	 * root.
+	 * Add 1 to strlen for leading '/' of each level.
+	 */
+	do {
+		if (kobject_name(parent) == NULL)
+			return 0;
+		length += strlen(kobject_name(parent)) + 1;
+		parent = parent->parent;
+	} while (parent);
+	return length;
+}
+
+static void fill_kobj_path(struct kobject *kobj, char *path, int length)
+{
+	struct kobject *parent;
+
+	--length;
+	for (parent = kobj; parent; parent = parent->parent) {
+		int cur = strlen(kobject_name(parent));
+		/* back up enough to print this name with '/' */
+		length -= cur;
+		memcpy(path + length, kobject_name(parent), cur);
+		*(path + --length) = '/';
+	}
+
+	pr_debug("kobject: '%s' (%p): %s: path = '%s'\n", kobject_name(kobj),
+		 kobj, __func__, path);
+}
+
+/**
+ * kobject_get_path - generate and return the path associated with a given kobj and kset pair.
+ *
+ * @kobj:	kobject in question, with which to build the path
+ * @gfp_mask:	the allocation type used to allocate the path
+ *
+ * The result must be freed by the caller with kfree().
+ */
+char *kobject_get_path(struct kobject *kobj, gfp_t gfp_mask)
+{
+	char *path;
+	int len;
+
+	len = get_kobj_path_length(kobj);
+	if (len == 0)
+		return NULL;
+	path = kzalloc(len, gfp_mask);
+	if (!path)
+		return NULL;
+	fill_kobj_path(kobj, path, len);
+
+	return path;
+}
+EXPORT_SYMBOL_GPL(kobject_get_path);
+
+/* add the kobject to its kset's list */
+static void kobj_kset_join(struct kobject *kobj)
+{
+	if (!kobj->kset)
+		return;
+
+	kset_get(kobj->kset);
+	spin_lock(&kobj->kset->list_lock);
+	list_add_tail(&kobj->entry, &kobj->kset->list);
+	spin_unlock(&kobj->kset->list_lock);
+}
+
+/* remove the kobject from its kset's list */
+static void kobj_kset_leave(struct kobject *kobj)
+{
+	if (!kobj->kset)
+		return;
+
+	spin_lock(&kobj->kset->list_lock);
+	list_del_init(&kobj->entry);
+	spin_unlock(&kobj->kset->list_lock);
+	kset_put(kobj->kset);
+}
+
+static void kobject_init_internal(struct kobject *kobj)
+{
+	if (!kobj)
+		return;
+	kref_init(&kobj->kref);
+	INIT_LIST_HEAD(&kobj->entry);
+	kobj->state_in_sysfs = 0;
+	kobj->state_add_uevent_sent = 0;
+	kobj->state_remove_uevent_sent = 0;
+	kobj->state_initialized = 1;
+}
+
+
+static int kobject_add_internal(struct kobject *kobj)
+{
+	int error = 0;
+	struct kobject *parent;
+
+	if (!kobj)
+		return -ENOENT;
+
+	if (!kobj->name || !kobj->name[0]) {
+		WARN(1,
+		     "kobject: (%p): attempted to be registered with empty name!\n",
+		     kobj);
+		return -EINVAL;
+	}
+
+	parent = kobject_get(kobj->parent);
+
+	/* join kset if set, use it as parent if we do not already have one */
+	if (kobj->kset) {
+		if (!parent)
+			parent = kobject_get(&kobj->kset->kobj);
+		kobj_kset_join(kobj);
+		kobj->parent = parent;
+	}
+
+	pr_debug("kobject: '%s' (%p): %s: parent: '%s', set: '%s'\n",
+		 kobject_name(kobj), kobj, __func__,
+		 parent ? kobject_name(parent) : "<NULL>",
+		 kobj->kset ? kobject_name(&kobj->kset->kobj) : "<NULL>");
+
+	error = create_dir(kobj);
+	if (error) {
+		kobj_kset_leave(kobj);
+		kobject_put(parent);
+		kobj->parent = NULL;
+
+		/* be noisy on error issues */
+		if (error == -EEXIST)
+			pr_err("%s failed for %s with -EEXIST, don't try to register things with the same name in the same directory.\n",
+			       __func__, kobject_name(kobj));
+		else
+			pr_err("%s failed for %s (error: %d parent: %s)\n",
+			       __func__, kobject_name(kobj), error,
+			       parent ? kobject_name(parent) : "'none'");
+	} else
+		kobj->state_in_sysfs = 1;
+
+	return error;
+}
+
+/**
+ * kobject_set_name_vargs - Set the name of an kobject
+ * @kobj: struct kobject to set the name of
+ * @fmt: format string used to build the name
+ * @vargs: vargs to format the string.
+ */
+int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
+				  va_list vargs)
+{
+	const char *s;
+
+	if (kobj->name && !fmt)
+		return 0;
+
+	s = kvasprintf_const(GFP_KERNEL, fmt, vargs);
+	if (!s)
+		return -ENOMEM;
+
+	/*
+	 * ewww... some of these buggers have '/' in the name ... If
+	 * that's the case, we need to make sure we have an actual
+	 * allocated copy to modify, since kvasprintf_const may have
+	 * returned something from .rodata.
+	 */
+	if (strchr(s, '/')) {
+		char *t;
+
+		t = kstrdup(s, GFP_KERNEL);
+		kfree_const(s);
+		if (!t)
+			return -ENOMEM;
+		strreplace(t, '/', '!');
+		s = t;
+	}
+	kfree_const(kobj->name);
+	kobj->name = s;
+
+	return 0;
+}
+
+/**
+ * kobject_set_name - Set the name of a kobject
+ * @kobj: struct kobject to set the name of
+ * @fmt: format string used to build the name
+ *
+ * This sets the name of the kobject.  If you have already added the
+ * kobject to the system, you must call kobject_rename() in order to
+ * change the name of the kobject.
+ */
+int kobject_set_name(struct kobject *kobj, const char *fmt, ...)
+{
+	va_list vargs;
+	int retval;
+
+	va_start(vargs, fmt);
+	retval = kobject_set_name_vargs(kobj, fmt, vargs);
+	va_end(vargs);
+
+	return retval;
+}
+EXPORT_SYMBOL(kobject_set_name);
+
+/**
+ * kobject_init - initialize a kobject structure
+ * @kobj: pointer to the kobject to initialize
+ * @ktype: pointer to the ktype for this kobject.
+ *
+ * This function will properly initialize a kobject such that it can then
+ * be passed to the kobject_add() call.
+ *
+ * After this function is called, the kobject MUST be cleaned up by a call
+ * to kobject_put(), not by a call to kfree directly to ensure that all of
+ * the memory is cleaned up properly.
+ */
+void kobject_init(struct kobject *kobj, struct kobj_type *ktype)
+{
+	char *err_str;
+
+	if (!kobj) {
+		err_str = "invalid kobject pointer!";
+		goto error;
+	}
+	if (!ktype) {
+		err_str = "must have a ktype to be initialized properly!\n";
+		goto error;
+	}
+	if (kobj->state_initialized) {
+		/* do not error out as sometimes we can recover */
+		pr_err("kobject (%p): tried to init an initialized object, something is seriously wrong.\n",
+		       kobj);
+		dump_stack();
+	}
+
+	kobject_init_internal(kobj);
+	kobj->ktype = ktype;
+	return;
+
+error:
+	pr_err("kobject (%p): %s\n", kobj, err_str);
+	dump_stack();
+}
+EXPORT_SYMBOL(kobject_init);
+
+static __printf(3, 0) int kobject_add_varg(struct kobject *kobj,
+					   struct kobject *parent,
+					   const char *fmt, va_list vargs)
+{
+	int retval;
+
+	retval = kobject_set_name_vargs(kobj, fmt, vargs);
+	if (retval) {
+		pr_err("kobject: can not set name properly!\n");
+		return retval;
+	}
+	kobj->parent = parent;
+	return kobject_add_internal(kobj);
+}
+
+/**
+ * kobject_add - the main kobject add function
+ * @kobj: the kobject to add
+ * @parent: pointer to the parent of the kobject.
+ * @fmt: format to name the kobject with.
+ *
+ * The kobject name is set and added to the kobject hierarchy in this
+ * function.
+ *
+ * If @parent is set, then the parent of the @kobj will be set to it.
+ * If @parent is NULL, then the parent of the @kobj will be set to the
+ * kobject associated with the kset assigned to this kobject.  If no kset
+ * is assigned to the kobject, then the kobject will be located in the
+ * root of the sysfs tree.
+ *
+ * If this function returns an error, kobject_put() must be called to
+ * properly clean up the memory associated with the object.
+ * Under no instance should the kobject that is passed to this function
+ * be directly freed with a call to kfree(), that can leak memory.
+ *
+ * Note, no "add" uevent will be created with this call, the caller should set
+ * up all of the necessary sysfs files for the object and then call
+ * kobject_uevent() with the UEVENT_ADD parameter to ensure that
+ * userspace is properly notified of this kobject's creation.
+ */
+int kobject_add(struct kobject *kobj, struct kobject *parent,
+		const char *fmt, ...)
+{
+	va_list args;
+	int retval;
+
+	if (!kobj)
+		return -EINVAL;
+
+	if (!kobj->state_initialized) {
+		pr_err("kobject '%s' (%p): tried to add an uninitialized object, something is seriously wrong.\n",
+		       kobject_name(kobj), kobj);
+		dump_stack();
+		return -EINVAL;
+	}
+	va_start(args, fmt);
+	retval = kobject_add_varg(kobj, parent, fmt, args);
+	va_end(args);
+
+	return retval;
+}
+EXPORT_SYMBOL(kobject_add);
+
+/**
+ * kobject_init_and_add - initialize a kobject structure and add it to the kobject hierarchy
+ * @kobj: pointer to the kobject to initialize
+ * @ktype: pointer to the ktype for this kobject.
+ * @parent: pointer to the parent of this kobject.
+ * @fmt: the name of the kobject.
+ *
+ * This function combines the call to kobject_init() and
+ * kobject_add().  The same type of error handling after a call to
+ * kobject_add() and kobject lifetime rules are the same here.
+ */
+int kobject_init_and_add(struct kobject *kobj, struct kobj_type *ktype,
+			 struct kobject *parent, const char *fmt, ...)
+{
+	va_list args;
+	int retval;
+
+	kobject_init(kobj, ktype);
+
+	va_start(args, fmt);
+	retval = kobject_add_varg(kobj, parent, fmt, args);
+	va_end(args);
+
+	return retval;
+}
+EXPORT_SYMBOL_GPL(kobject_init_and_add);
+
+/**
+ * kobject_rename - change the name of an object
+ * @kobj: object in question.
+ * @new_name: object's new name
+ *
+ * It is the responsibility of the caller to provide mutual
+ * exclusion between two different calls of kobject_rename
+ * on the same kobject and to ensure that new_name is valid and
+ * won't conflict with other kobjects.
+ */
+int kobject_rename(struct kobject *kobj, const char *new_name)
+{
+	int error = 0;
+	const char *devpath = NULL;
+	const char *dup_name = NULL, *name;
+	char *devpath_string = NULL;
+	char *envp[2];
+
+	kobj = kobject_get(kobj);
+	if (!kobj)
+		return -EINVAL;
+	if (!kobj->parent)
+		return -EINVAL;
+
+	devpath = kobject_get_path(kobj, GFP_KERNEL);
+	if (!devpath) {
+		error = -ENOMEM;
+		goto out;
+	}
+	devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
+	if (!devpath_string) {
+		error = -ENOMEM;
+		goto out;
+	}
+	sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
+	envp[0] = devpath_string;
+	envp[1] = NULL;
+
+	name = dup_name = kstrdup_const(new_name, GFP_KERNEL);
+	if (!name) {
+		error = -ENOMEM;
+		goto out;
+	}
+
+	error = sysfs_rename_dir_ns(kobj, new_name, kobject_namespace(kobj));
+	if (error)
+		goto out;
+
+	/* Install the new kobject name */
+	dup_name = kobj->name;
+	kobj->name = name;
+
+	/* This function is mostly/only used for network interface.
+	 * Some hotplug package track interfaces by their name and
+	 * therefore want to know when the name is changed by the user. */
+	kobject_uevent_env(kobj, KOBJ_MOVE, envp);
+
+out:
+	kfree_const(dup_name);
+	kfree(devpath_string);
+	kfree(devpath);
+	kobject_put(kobj);
+
+	return error;
+}
+EXPORT_SYMBOL_GPL(kobject_rename);
+
+/**
+ * kobject_move - move object to another parent
+ * @kobj: object in question.
+ * @new_parent: object's new parent (can be NULL)
+ */
+int kobject_move(struct kobject *kobj, struct kobject *new_parent)
+{
+	int error;
+	struct kobject *old_parent;
+	const char *devpath = NULL;
+	char *devpath_string = NULL;
+	char *envp[2];
+
+	kobj = kobject_get(kobj);
+	if (!kobj)
+		return -EINVAL;
+	new_parent = kobject_get(new_parent);
+	if (!new_parent) {
+		if (kobj->kset)
+			new_parent = kobject_get(&kobj->kset->kobj);
+	}
+
+	/* old object path */
+	devpath = kobject_get_path(kobj, GFP_KERNEL);
+	if (!devpath) {
+		error = -ENOMEM;
+		goto out;
+	}
+	devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
+	if (!devpath_string) {
+		error = -ENOMEM;
+		goto out;
+	}
+	sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
+	envp[0] = devpath_string;
+	envp[1] = NULL;
+	error = sysfs_move_dir_ns(kobj, new_parent, kobject_namespace(kobj));
+	if (error)
+		goto out;
+	old_parent = kobj->parent;
+	kobj->parent = new_parent;
+	new_parent = NULL;
+	kobject_put(old_parent);
+	kobject_uevent_env(kobj, KOBJ_MOVE, envp);
+out:
+	kobject_put(new_parent);
+	kobject_put(kobj);
+	kfree(devpath_string);
+	kfree(devpath);
+	return error;
+}
+EXPORT_SYMBOL_GPL(kobject_move);
+
+/**
+ * kobject_del - unlink kobject from hierarchy.
+ * @kobj: object.
+ */
+void kobject_del(struct kobject *kobj)
+{
+	struct kernfs_node *sd;
+
+	if (!kobj)
+		return;
+
+	sd = kobj->sd;
+	sysfs_remove_dir(kobj);
+	sysfs_put(sd);
+
+	kobj->state_in_sysfs = 0;
+	kobj_kset_leave(kobj);
+	kobject_put(kobj->parent);
+	kobj->parent = NULL;
+}
+EXPORT_SYMBOL(kobject_del);
+
+/**
+ * kobject_get - increment refcount for object.
+ * @kobj: object.
+ */
+struct kobject *kobject_get(struct kobject *kobj)
+{
+	if (kobj) {
+		if (!kobj->state_initialized)
+			WARN(1, KERN_WARNING
+				"kobject: '%s' (%p): is not initialized, yet kobject_get() is being called.\n",
+			     kobject_name(kobj), kobj);
+		kref_get(&kobj->kref);
+	}
+	return kobj;
+}
+EXPORT_SYMBOL(kobject_get);
+
+struct kobject * __must_check kobject_get_unless_zero(struct kobject *kobj)
+{
+	if (!kobj)
+		return NULL;
+	if (!kref_get_unless_zero(&kobj->kref))
+		kobj = NULL;
+	return kobj;
+}
+EXPORT_SYMBOL(kobject_get_unless_zero);
+
+/*
+ * kobject_cleanup - free kobject resources.
+ * @kobj: object to cleanup
+ */
+static void kobject_cleanup(struct kobject *kobj)
+{
+	struct kobj_type *t = get_ktype(kobj);
+	const char *name = kobj->name;
+
+	pr_debug("kobject: '%s' (%p): %s, parent %p\n",
+		 kobject_name(kobj), kobj, __func__, kobj->parent);
+
+	if (t && !t->release)
+		pr_debug("kobject: '%s' (%p): does not have a release() function, it is broken and must be fixed.\n",
+			 kobject_name(kobj), kobj);
+
+	/* send "remove" if the caller did not do it but sent "add" */
+	if (kobj->state_add_uevent_sent && !kobj->state_remove_uevent_sent) {
+		pr_debug("kobject: '%s' (%p): auto cleanup 'remove' event\n",
+			 kobject_name(kobj), kobj);
+		kobject_uevent(kobj, KOBJ_REMOVE);
+	}
+
+	/* remove from sysfs if the caller did not do it */
+	if (kobj->state_in_sysfs) {
+		pr_debug("kobject: '%s' (%p): auto cleanup kobject_del\n",
+			 kobject_name(kobj), kobj);
+		kobject_del(kobj);
+	}
+
+	if (t && t->release) {
+		pr_debug("kobject: '%s' (%p): calling ktype release\n",
+			 kobject_name(kobj), kobj);
+		t->release(kobj);
+	}
+
+	/* free name if we allocated it */
+	if (name) {
+		pr_debug("kobject: '%s': free name\n", name);
+		kfree_const(name);
+	}
+}
+
+#ifdef CONFIG_DEBUG_KOBJECT_RELEASE
+static void kobject_delayed_cleanup(struct work_struct *work)
+{
+	kobject_cleanup(container_of(to_delayed_work(work),
+				     struct kobject, release));
+}
+#endif
+
+static void kobject_release(struct kref *kref)
+{
+	struct kobject *kobj = container_of(kref, struct kobject, kref);
+#ifdef CONFIG_DEBUG_KOBJECT_RELEASE
+	unsigned long delay = HZ + HZ * (get_random_int() & 0x3);
+	pr_info("kobject: '%s' (%p): %s, parent %p (delayed %ld)\n",
+		 kobject_name(kobj), kobj, __func__, kobj->parent, delay);
+	INIT_DELAYED_WORK(&kobj->release, kobject_delayed_cleanup);
+
+	schedule_delayed_work(&kobj->release, delay);
+#else
+	kobject_cleanup(kobj);
+#endif
+}
+
+/**
+ * kobject_put - decrement refcount for object.
+ * @kobj: object.
+ *
+ * Decrement the refcount, and if 0, call kobject_cleanup().
+ */
+void kobject_put(struct kobject *kobj)
+{
+	if (kobj) {
+		if (!kobj->state_initialized)
+			WARN(1, KERN_WARNING
+				"kobject: '%s' (%p): is not initialized, yet kobject_put() is being called.\n",
+			     kobject_name(kobj), kobj);
+		kref_put(&kobj->kref, kobject_release);
+	}
+}
+EXPORT_SYMBOL(kobject_put);
+
+static void dynamic_kobj_release(struct kobject *kobj)
+{
+	pr_debug("kobject: (%p): %s\n", kobj, __func__);
+	kfree(kobj);
+}
+
+static struct kobj_type dynamic_kobj_ktype = {
+	.release	= dynamic_kobj_release,
+	.sysfs_ops	= &kobj_sysfs_ops,
+};
+
+/**
+ * kobject_create - create a struct kobject dynamically
+ *
+ * This function creates a kobject structure dynamically and sets it up
+ * to be a "dynamic" kobject with a default release function set up.
+ *
+ * If the kobject was not able to be created, NULL will be returned.
+ * The kobject structure returned from here must be cleaned up with a
+ * call to kobject_put() and not kfree(), as kobject_init() has
+ * already been called on this structure.
+ */
+struct kobject *kobject_create(void)
+{
+	struct kobject *kobj;
+
+	kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
+	if (!kobj)
+		return NULL;
+
+	kobject_init(kobj, &dynamic_kobj_ktype);
+	return kobj;
+}
+
+/**
+ * kobject_create_and_add - create a struct kobject dynamically and register it with sysfs
+ *
+ * @name: the name for the kobject
+ * @parent: the parent kobject of this kobject, if any.
+ *
+ * This function creates a kobject structure dynamically and registers it
+ * with sysfs.  When you are finished with this structure, call
+ * kobject_put() and the structure will be dynamically freed when
+ * it is no longer being used.
+ *
+ * If the kobject was not able to be created, NULL will be returned.
+ */
+struct kobject *kobject_create_and_add(const char *name, struct kobject *parent)
+{
+	struct kobject *kobj;
+	int retval;
+
+	kobj = kobject_create();
+	if (!kobj)
+		return NULL;
+
+	retval = kobject_add(kobj, parent, "%s", name);
+	if (retval) {
+		pr_warn("%s: kobject_add error: %d\n", __func__, retval);
+		kobject_put(kobj);
+		kobj = NULL;
+	}
+	return kobj;
+}
+EXPORT_SYMBOL_GPL(kobject_create_and_add);
+
+/**
+ * kset_init - initialize a kset for use
+ * @k: kset
+ */
+void kset_init(struct kset *k)
+{
+	kobject_init_internal(&k->kobj);
+	INIT_LIST_HEAD(&k->list);
+	spin_lock_init(&k->list_lock);
+}
+
+/* default kobject attribute operations */
+static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
+			      char *buf)
+{
+	struct kobj_attribute *kattr;
+	ssize_t ret = -EIO;
+
+	kattr = container_of(attr, struct kobj_attribute, attr);
+	if (kattr->show)
+		ret = kattr->show(kobj, kattr, buf);
+	return ret;
+}
+
+static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute *attr,
+			       const char *buf, size_t count)
+{
+	struct kobj_attribute *kattr;
+	ssize_t ret = -EIO;
+
+	kattr = container_of(attr, struct kobj_attribute, attr);
+	if (kattr->store)
+		ret = kattr->store(kobj, kattr, buf, count);
+	return ret;
+}
+
+const struct sysfs_ops kobj_sysfs_ops = {
+	.show	= kobj_attr_show,
+	.store	= kobj_attr_store,
+};
+EXPORT_SYMBOL_GPL(kobj_sysfs_ops);
+
+/**
+ * kset_register - initialize and add a kset.
+ * @k: kset.
+ */
+int kset_register(struct kset *k)
+{
+	int err;
+
+	if (!k)
+		return -EINVAL;
+
+	kset_init(k);
+	err = kobject_add_internal(&k->kobj);
+	if (err)
+		return err;
+	kobject_uevent(&k->kobj, KOBJ_ADD);
+	return 0;
+}
+EXPORT_SYMBOL(kset_register);
+
+/**
+ * kset_unregister - remove a kset.
+ * @k: kset.
+ */
+void kset_unregister(struct kset *k)
+{
+	if (!k)
+		return;
+	kobject_del(&k->kobj);
+	kobject_put(&k->kobj);
+}
+EXPORT_SYMBOL(kset_unregister);
+
+/**
+ * kset_find_obj - search for object in kset.
+ * @kset: kset we're looking in.
+ * @name: object's name.
+ *
+ * Lock kset via @kset->subsys, and iterate over @kset->list,
+ * looking for a matching kobject. If matching object is found
+ * take a reference and return the object.
+ */
+struct kobject *kset_find_obj(struct kset *kset, const char *name)
+{
+	struct kobject *k;
+	struct kobject *ret = NULL;
+
+	spin_lock(&kset->list_lock);
+
+	list_for_each_entry(k, &kset->list, entry) {
+		if (kobject_name(k) && !strcmp(kobject_name(k), name)) {
+			ret = kobject_get_unless_zero(k);
+			break;
+		}
+	}
+
+	spin_unlock(&kset->list_lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(kset_find_obj);
+
+static void kset_release(struct kobject *kobj)
+{
+	struct kset *kset = container_of(kobj, struct kset, kobj);
+	pr_debug("kobject: '%s' (%p): %s\n",
+		 kobject_name(kobj), kobj, __func__);
+	kfree(kset);
+}
+
+void kset_get_ownership(struct kobject *kobj, kuid_t *uid, kgid_t *gid)
+{
+	if (kobj->parent)
+		kobject_get_ownership(kobj->parent, uid, gid);
+}
+
+static struct kobj_type kset_ktype = {
+	.sysfs_ops	= &kobj_sysfs_ops,
+	.release	= kset_release,
+	.get_ownership	= kset_get_ownership,
+};
+
+/**
+ * kset_create - create a struct kset dynamically
+ *
+ * @name: the name for the kset
+ * @uevent_ops: a struct kset_uevent_ops for the kset
+ * @parent_kobj: the parent kobject of this kset, if any.
+ *
+ * This function creates a kset structure dynamically.  This structure can
+ * then be registered with the system and show up in sysfs with a call to
+ * kset_register().  When you are finished with this structure, if
+ * kset_register() has been called, call kset_unregister() and the
+ * structure will be dynamically freed when it is no longer being used.
+ *
+ * If the kset was not able to be created, NULL will be returned.
+ */
+static struct kset *kset_create(const char *name,
+				const struct kset_uevent_ops *uevent_ops,
+				struct kobject *parent_kobj)
+{
+	struct kset *kset;
+	int retval;
+
+	kset = kzalloc(sizeof(*kset), GFP_KERNEL);
+	if (!kset)
+		return NULL;
+	retval = kobject_set_name(&kset->kobj, "%s", name);
+	if (retval) {
+		kfree(kset);
+		return NULL;
+	}
+	kset->uevent_ops = uevent_ops;
+	kset->kobj.parent = parent_kobj;
+
+	/*
+	 * The kobject of this kset will have a type of kset_ktype and belong to
+	 * no kset itself.  That way we can properly free it when it is
+	 * finished being used.
+	 */
+	kset->kobj.ktype = &kset_ktype;
+	kset->kobj.kset = NULL;
+
+	return kset;
+}
+
+/**
+ * kset_create_and_add - create a struct kset dynamically and add it to sysfs
+ *
+ * @name: the name for the kset
+ * @uevent_ops: a struct kset_uevent_ops for the kset
+ * @parent_kobj: the parent kobject of this kset, if any.
+ *
+ * This function creates a kset structure dynamically and registers it
+ * with sysfs.  When you are finished with this structure, call
+ * kset_unregister() and the structure will be dynamically freed when it
+ * is no longer being used.
+ *
+ * If the kset was not able to be created, NULL will be returned.
+ */
+struct kset *kset_create_and_add(const char *name,
+				 const struct kset_uevent_ops *uevent_ops,
+				 struct kobject *parent_kobj)
+{
+	struct kset *kset;
+	int error;
+
+	kset = kset_create(name, uevent_ops, parent_kobj);
+	if (!kset)
+		return NULL;
+	error = kset_register(kset);
+	if (error) {
+		kfree(kset);
+		return NULL;
+	}
+	return kset;
+}
+EXPORT_SYMBOL_GPL(kset_create_and_add);
+
+
+static DEFINE_SPINLOCK(kobj_ns_type_lock);
+static const struct kobj_ns_type_operations *kobj_ns_ops_tbl[KOBJ_NS_TYPES];
+
+int kobj_ns_type_register(const struct kobj_ns_type_operations *ops)
+{
+	enum kobj_ns_type type = ops->type;
+	int error;
+
+	spin_lock(&kobj_ns_type_lock);
+
+	error = -EINVAL;
+	if (type >= KOBJ_NS_TYPES)
+		goto out;
+
+	error = -EINVAL;
+	if (type <= KOBJ_NS_TYPE_NONE)
+		goto out;
+
+	error = -EBUSY;
+	if (kobj_ns_ops_tbl[type])
+		goto out;
+
+	error = 0;
+	kobj_ns_ops_tbl[type] = ops;
+
+out:
+	spin_unlock(&kobj_ns_type_lock);
+	return error;
+}
+
+int kobj_ns_type_registered(enum kobj_ns_type type)
+{
+	int registered = 0;
+
+	spin_lock(&kobj_ns_type_lock);
+	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES))
+		registered = kobj_ns_ops_tbl[type] != NULL;
+	spin_unlock(&kobj_ns_type_lock);
+
+	return registered;
+}
+
+const struct kobj_ns_type_operations *kobj_child_ns_ops(struct kobject *parent)
+{
+	const struct kobj_ns_type_operations *ops = NULL;
+
+	if (parent && parent->ktype && parent->ktype->child_ns_type)
+		ops = parent->ktype->child_ns_type(parent);
+
+	return ops;
+}
+
+const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj)
+{
+	return kobj_child_ns_ops(kobj->parent);
+}
+
+bool kobj_ns_current_may_mount(enum kobj_ns_type type)
+{
+	bool may_mount = true;
+
+	spin_lock(&kobj_ns_type_lock);
+	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
+	    kobj_ns_ops_tbl[type])
+		may_mount = kobj_ns_ops_tbl[type]->current_may_mount();
+	spin_unlock(&kobj_ns_type_lock);
+
+	return may_mount;
+}
+
+void *kobj_ns_grab_current(enum kobj_ns_type type)
+{
+	void *ns = NULL;
+
+	spin_lock(&kobj_ns_type_lock);
+	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
+	    kobj_ns_ops_tbl[type])
+		ns = kobj_ns_ops_tbl[type]->grab_current_ns();
+	spin_unlock(&kobj_ns_type_lock);
+
+	return ns;
+}
+EXPORT_SYMBOL_GPL(kobj_ns_grab_current);
+
+const void *kobj_ns_netlink(enum kobj_ns_type type, struct sock *sk)
+{
+	const void *ns = NULL;
+
+	spin_lock(&kobj_ns_type_lock);
+	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
+	    kobj_ns_ops_tbl[type])
+		ns = kobj_ns_ops_tbl[type]->netlink_ns(sk);
+	spin_unlock(&kobj_ns_type_lock);
+
+	return ns;
+}
+
+const void *kobj_ns_initial(enum kobj_ns_type type)
+{
+	const void *ns = NULL;
+
+	spin_lock(&kobj_ns_type_lock);
+	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
+	    kobj_ns_ops_tbl[type])
+		ns = kobj_ns_ops_tbl[type]->initial_ns();
+	spin_unlock(&kobj_ns_type_lock);
+
+	return ns;
+}
+
+void kobj_ns_drop(enum kobj_ns_type type, void *ns)
+{
+	spin_lock(&kobj_ns_type_lock);
+	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
+	    kobj_ns_ops_tbl[type] && kobj_ns_ops_tbl[type]->drop_ns)
+		kobj_ns_ops_tbl[type]->drop_ns(ns);
+	spin_unlock(&kobj_ns_type_lock);
+}
+EXPORT_SYMBOL_GPL(kobj_ns_drop);