v4.19.13 snapshot.
diff --git a/fs/sysfs/Kconfig b/fs/sysfs/Kconfig
new file mode 100644
index 0000000..b275601
--- /dev/null
+++ b/fs/sysfs/Kconfig
@@ -0,0 +1,24 @@
+config SYSFS
+ bool "sysfs file system support" if EXPERT
+ default y
+ select KERNFS
+ help
+ The sysfs filesystem is a virtual filesystem that the kernel uses to
+ export internal kernel objects, their attributes, and their
+ relationships to one another.
+
+ Users can use sysfs to ascertain useful information about the running
+ kernel, such as the devices the kernel has discovered on each bus and
+ which driver each is bound to. sysfs can also be used to tune devices
+ and other kernel subsystems.
+
+ Some system agents rely on the information in sysfs to operate.
+ /sbin/hotplug uses device and object attributes in sysfs to assist in
+ delegating policy decisions, like persistently naming devices.
+
+ sysfs is currently used by the block subsystem to mount the root
+ partition. If sysfs is disabled you must specify the boot device on
+ the kernel boot command line via its major and minor numbers. For
+ example, "root=03:01" for /dev/hda1.
+
+ Designers of embedded systems may wish to say N here to conserve space.
diff --git a/fs/sysfs/Makefile b/fs/sysfs/Makefile
new file mode 100644
index 0000000..6eff6e1
--- /dev/null
+++ b/fs/sysfs/Makefile
@@ -0,0 +1,5 @@
+#
+# Makefile for the sysfs virtual filesystem
+#
+
+obj-y := file.o dir.o symlink.o mount.o group.o
diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
new file mode 100644
index 0000000..feeae80
--- /dev/null
+++ b/fs/sysfs/dir.c
@@ -0,0 +1,161 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * fs/sysfs/dir.c - sysfs core and dir operation implementation
+ *
+ * Copyright (c) 2001-3 Patrick Mochel
+ * Copyright (c) 2007 SUSE Linux Products GmbH
+ * Copyright (c) 2007 Tejun Heo <teheo@suse.de>
+ *
+ * Please see Documentation/filesystems/sysfs.txt for more information.
+ */
+
+#define pr_fmt(fmt) "sysfs: " fmt
+
+#include <linux/fs.h>
+#include <linux/kobject.h>
+#include <linux/slab.h>
+#include "sysfs.h"
+
+DEFINE_SPINLOCK(sysfs_symlink_target_lock);
+
+void sysfs_warn_dup(struct kernfs_node *parent, const char *name)
+{
+ char *buf;
+
+ buf = kzalloc(PATH_MAX, GFP_KERNEL);
+ if (buf)
+ kernfs_path(parent, buf, PATH_MAX);
+
+ pr_warn("cannot create duplicate filename '%s/%s'\n", buf, name);
+ dump_stack();
+
+ kfree(buf);
+}
+
+/**
+ * sysfs_create_dir_ns - create a directory for an object with a namespace tag
+ * @kobj: object we're creating directory for
+ * @ns: the namespace tag to use
+ */
+int sysfs_create_dir_ns(struct kobject *kobj, const void *ns)
+{
+ struct kernfs_node *parent, *kn;
+ kuid_t uid;
+ kgid_t gid;
+
+ BUG_ON(!kobj);
+
+ if (kobj->parent)
+ parent = kobj->parent->sd;
+ else
+ parent = sysfs_root_kn;
+
+ if (!parent)
+ return -ENOENT;
+
+ kobject_get_ownership(kobj, &uid, &gid);
+
+ kn = kernfs_create_dir_ns(parent, kobject_name(kobj),
+ S_IRWXU | S_IRUGO | S_IXUGO, uid, gid,
+ kobj, ns);
+ if (IS_ERR(kn)) {
+ if (PTR_ERR(kn) == -EEXIST)
+ sysfs_warn_dup(parent, kobject_name(kobj));
+ return PTR_ERR(kn);
+ }
+
+ kobj->sd = kn;
+ return 0;
+}
+
+/**
+ * sysfs_remove_dir - remove an object's directory.
+ * @kobj: object.
+ *
+ * The only thing special about this is that we remove any files in
+ * the directory before we remove the directory, and we've inlined
+ * what used to be sysfs_rmdir() below, instead of calling separately.
+ */
+void sysfs_remove_dir(struct kobject *kobj)
+{
+ struct kernfs_node *kn = kobj->sd;
+
+ /*
+ * In general, kboject owner is responsible for ensuring removal
+ * doesn't race with other operations and sysfs doesn't provide any
+ * protection; however, when @kobj is used as a symlink target, the
+ * symlinking entity usually doesn't own @kobj and thus has no
+ * control over removal. @kobj->sd may be removed anytime
+ * and symlink code may end up dereferencing an already freed node.
+ *
+ * sysfs_symlink_target_lock synchronizes @kobj->sd
+ * disassociation against symlink operations so that symlink code
+ * can safely dereference @kobj->sd.
+ */
+ spin_lock(&sysfs_symlink_target_lock);
+ kobj->sd = NULL;
+ spin_unlock(&sysfs_symlink_target_lock);
+
+ if (kn) {
+ WARN_ON_ONCE(kernfs_type(kn) != KERNFS_DIR);
+ kernfs_remove(kn);
+ }
+}
+
+int sysfs_rename_dir_ns(struct kobject *kobj, const char *new_name,
+ const void *new_ns)
+{
+ struct kernfs_node *parent;
+ int ret;
+
+ parent = kernfs_get_parent(kobj->sd);
+ ret = kernfs_rename_ns(kobj->sd, parent, new_name, new_ns);
+ kernfs_put(parent);
+ return ret;
+}
+
+int sysfs_move_dir_ns(struct kobject *kobj, struct kobject *new_parent_kobj,
+ const void *new_ns)
+{
+ struct kernfs_node *kn = kobj->sd;
+ struct kernfs_node *new_parent;
+
+ new_parent = new_parent_kobj && new_parent_kobj->sd ?
+ new_parent_kobj->sd : sysfs_root_kn;
+
+ return kernfs_rename_ns(kn, new_parent, kn->name, new_ns);
+}
+
+/**
+ * sysfs_create_mount_point - create an always empty directory
+ * @parent_kobj: kobject that will contain this always empty directory
+ * @name: The name of the always empty directory to add
+ */
+int sysfs_create_mount_point(struct kobject *parent_kobj, const char *name)
+{
+ struct kernfs_node *kn, *parent = parent_kobj->sd;
+
+ kn = kernfs_create_empty_dir(parent, name);
+ if (IS_ERR(kn)) {
+ if (PTR_ERR(kn) == -EEXIST)
+ sysfs_warn_dup(parent, name);
+ return PTR_ERR(kn);
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(sysfs_create_mount_point);
+
+/**
+ * sysfs_remove_mount_point - remove an always empty directory.
+ * @parent_kobj: kobject that will contain this always empty directory
+ * @name: The name of the always empty directory to remove
+ *
+ */
+void sysfs_remove_mount_point(struct kobject *parent_kobj, const char *name)
+{
+ struct kernfs_node *parent = parent_kobj->sd;
+
+ kernfs_remove_by_name_ns(parent, name, NULL);
+}
+EXPORT_SYMBOL_GPL(sysfs_remove_mount_point);
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
new file mode 100644
index 0000000..0a7252a
--- /dev/null
+++ b/fs/sysfs/file.c
@@ -0,0 +1,558 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * fs/sysfs/file.c - sysfs regular (text) file implementation
+ *
+ * Copyright (c) 2001-3 Patrick Mochel
+ * Copyright (c) 2007 SUSE Linux Products GmbH
+ * Copyright (c) 2007 Tejun Heo <teheo@suse.de>
+ *
+ * Please see Documentation/filesystems/sysfs.txt for more information.
+ */
+
+#include <linux/module.h>
+#include <linux/kobject.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/seq_file.h>
+
+#include "sysfs.h"
+#include "../kernfs/kernfs-internal.h"
+
+/*
+ * Determine ktype->sysfs_ops for the given kernfs_node. This function
+ * must be called while holding an active reference.
+ */
+static const struct sysfs_ops *sysfs_file_ops(struct kernfs_node *kn)
+{
+ struct kobject *kobj = kn->parent->priv;
+
+ if (kn->flags & KERNFS_LOCKDEP)
+ lockdep_assert_held(kn);
+ return kobj->ktype ? kobj->ktype->sysfs_ops : NULL;
+}
+
+/*
+ * Reads on sysfs are handled through seq_file, which takes care of hairy
+ * details like buffering and seeking. The following function pipes
+ * sysfs_ops->show() result through seq_file.
+ */
+static int sysfs_kf_seq_show(struct seq_file *sf, void *v)
+{
+ struct kernfs_open_file *of = sf->private;
+ struct kobject *kobj = of->kn->parent->priv;
+ const struct sysfs_ops *ops = sysfs_file_ops(of->kn);
+ ssize_t count;
+ char *buf;
+
+ /* acquire buffer and ensure that it's >= PAGE_SIZE and clear */
+ count = seq_get_buf(sf, &buf);
+ if (count < PAGE_SIZE) {
+ seq_commit(sf, -1);
+ return 0;
+ }
+ memset(buf, 0, PAGE_SIZE);
+
+ /*
+ * Invoke show(). Control may reach here via seq file lseek even
+ * if @ops->show() isn't implemented.
+ */
+ if (ops->show) {
+ count = ops->show(kobj, of->kn->priv, buf);
+ if (count < 0)
+ return count;
+ }
+
+ /*
+ * The code works fine with PAGE_SIZE return but it's likely to
+ * indicate truncated result or overflow in normal use cases.
+ */
+ if (count >= (ssize_t)PAGE_SIZE) {
+ printk("fill_read_buffer: %pS returned bad count\n",
+ ops->show);
+ /* Try to struggle along */
+ count = PAGE_SIZE - 1;
+ }
+ seq_commit(sf, count);
+ return 0;
+}
+
+static ssize_t sysfs_kf_bin_read(struct kernfs_open_file *of, char *buf,
+ size_t count, loff_t pos)
+{
+ struct bin_attribute *battr = of->kn->priv;
+ struct kobject *kobj = of->kn->parent->priv;
+ loff_t size = file_inode(of->file)->i_size;
+
+ if (!count)
+ return 0;
+
+ if (size) {
+ if (pos >= size)
+ return 0;
+ if (pos + count > size)
+ count = size - pos;
+ }
+
+ if (!battr->read)
+ return -EIO;
+
+ return battr->read(of->file, kobj, battr, buf, pos, count);
+}
+
+/* kernfs read callback for regular sysfs files with pre-alloc */
+static ssize_t sysfs_kf_read(struct kernfs_open_file *of, char *buf,
+ size_t count, loff_t pos)
+{
+ const struct sysfs_ops *ops = sysfs_file_ops(of->kn);
+ struct kobject *kobj = of->kn->parent->priv;
+ ssize_t len;
+
+ /*
+ * If buf != of->prealloc_buf, we don't know how
+ * large it is, so cannot safely pass it to ->show
+ */
+ if (WARN_ON_ONCE(buf != of->prealloc_buf))
+ return 0;
+ len = ops->show(kobj, of->kn->priv, buf);
+ if (len < 0)
+ return len;
+ if (pos) {
+ if (len <= pos)
+ return 0;
+ len -= pos;
+ memmove(buf, buf + pos, len);
+ }
+ return min_t(ssize_t, count, len);
+}
+
+/* kernfs write callback for regular sysfs files */
+static ssize_t sysfs_kf_write(struct kernfs_open_file *of, char *buf,
+ size_t count, loff_t pos)
+{
+ const struct sysfs_ops *ops = sysfs_file_ops(of->kn);
+ struct kobject *kobj = of->kn->parent->priv;
+
+ if (!count)
+ return 0;
+
+ return ops->store(kobj, of->kn->priv, buf, count);
+}
+
+/* kernfs write callback for bin sysfs files */
+static ssize_t sysfs_kf_bin_write(struct kernfs_open_file *of, char *buf,
+ size_t count, loff_t pos)
+{
+ struct bin_attribute *battr = of->kn->priv;
+ struct kobject *kobj = of->kn->parent->priv;
+ loff_t size = file_inode(of->file)->i_size;
+
+ if (size) {
+ if (size <= pos)
+ return -EFBIG;
+ count = min_t(ssize_t, count, size - pos);
+ }
+ if (!count)
+ return 0;
+
+ if (!battr->write)
+ return -EIO;
+
+ return battr->write(of->file, kobj, battr, buf, pos, count);
+}
+
+static int sysfs_kf_bin_mmap(struct kernfs_open_file *of,
+ struct vm_area_struct *vma)
+{
+ struct bin_attribute *battr = of->kn->priv;
+ struct kobject *kobj = of->kn->parent->priv;
+
+ return battr->mmap(of->file, kobj, battr, vma);
+}
+
+void sysfs_notify(struct kobject *kobj, const char *dir, const char *attr)
+{
+ struct kernfs_node *kn = kobj->sd, *tmp;
+
+ if (kn && dir)
+ kn = kernfs_find_and_get(kn, dir);
+ else
+ kernfs_get(kn);
+
+ if (kn && attr) {
+ tmp = kernfs_find_and_get(kn, attr);
+ kernfs_put(kn);
+ kn = tmp;
+ }
+
+ if (kn) {
+ kernfs_notify(kn);
+ kernfs_put(kn);
+ }
+}
+EXPORT_SYMBOL_GPL(sysfs_notify);
+
+static const struct kernfs_ops sysfs_file_kfops_empty = {
+};
+
+static const struct kernfs_ops sysfs_file_kfops_ro = {
+ .seq_show = sysfs_kf_seq_show,
+};
+
+static const struct kernfs_ops sysfs_file_kfops_wo = {
+ .write = sysfs_kf_write,
+};
+
+static const struct kernfs_ops sysfs_file_kfops_rw = {
+ .seq_show = sysfs_kf_seq_show,
+ .write = sysfs_kf_write,
+};
+
+static const struct kernfs_ops sysfs_prealloc_kfops_ro = {
+ .read = sysfs_kf_read,
+ .prealloc = true,
+};
+
+static const struct kernfs_ops sysfs_prealloc_kfops_wo = {
+ .write = sysfs_kf_write,
+ .prealloc = true,
+};
+
+static const struct kernfs_ops sysfs_prealloc_kfops_rw = {
+ .read = sysfs_kf_read,
+ .write = sysfs_kf_write,
+ .prealloc = true,
+};
+
+static const struct kernfs_ops sysfs_bin_kfops_ro = {
+ .read = sysfs_kf_bin_read,
+};
+
+static const struct kernfs_ops sysfs_bin_kfops_wo = {
+ .write = sysfs_kf_bin_write,
+};
+
+static const struct kernfs_ops sysfs_bin_kfops_rw = {
+ .read = sysfs_kf_bin_read,
+ .write = sysfs_kf_bin_write,
+};
+
+static const struct kernfs_ops sysfs_bin_kfops_mmap = {
+ .read = sysfs_kf_bin_read,
+ .write = sysfs_kf_bin_write,
+ .mmap = sysfs_kf_bin_mmap,
+};
+
+int sysfs_add_file_mode_ns(struct kernfs_node *parent,
+ const struct attribute *attr, bool is_bin,
+ umode_t mode, kuid_t uid, kgid_t gid, const void *ns)
+{
+ struct lock_class_key *key = NULL;
+ const struct kernfs_ops *ops;
+ struct kernfs_node *kn;
+ loff_t size;
+
+ if (!is_bin) {
+ struct kobject *kobj = parent->priv;
+ const struct sysfs_ops *sysfs_ops = kobj->ktype->sysfs_ops;
+
+ /* every kobject with an attribute needs a ktype assigned */
+ if (WARN(!sysfs_ops, KERN_ERR
+ "missing sysfs attribute operations for kobject: %s\n",
+ kobject_name(kobj)))
+ return -EINVAL;
+
+ if (sysfs_ops->show && sysfs_ops->store) {
+ if (mode & SYSFS_PREALLOC)
+ ops = &sysfs_prealloc_kfops_rw;
+ else
+ ops = &sysfs_file_kfops_rw;
+ } else if (sysfs_ops->show) {
+ if (mode & SYSFS_PREALLOC)
+ ops = &sysfs_prealloc_kfops_ro;
+ else
+ ops = &sysfs_file_kfops_ro;
+ } else if (sysfs_ops->store) {
+ if (mode & SYSFS_PREALLOC)
+ ops = &sysfs_prealloc_kfops_wo;
+ else
+ ops = &sysfs_file_kfops_wo;
+ } else
+ ops = &sysfs_file_kfops_empty;
+
+ size = PAGE_SIZE;
+ } else {
+ struct bin_attribute *battr = (void *)attr;
+
+ if (battr->mmap)
+ ops = &sysfs_bin_kfops_mmap;
+ else if (battr->read && battr->write)
+ ops = &sysfs_bin_kfops_rw;
+ else if (battr->read)
+ ops = &sysfs_bin_kfops_ro;
+ else if (battr->write)
+ ops = &sysfs_bin_kfops_wo;
+ else
+ ops = &sysfs_file_kfops_empty;
+
+ size = battr->size;
+ }
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ if (!attr->ignore_lockdep)
+ key = attr->key ?: (struct lock_class_key *)&attr->skey;
+#endif
+
+ kn = __kernfs_create_file(parent, attr->name, mode & 0777, uid, gid,
+ size, ops, (void *)attr, ns, key);
+ if (IS_ERR(kn)) {
+ if (PTR_ERR(kn) == -EEXIST)
+ sysfs_warn_dup(parent, attr->name);
+ return PTR_ERR(kn);
+ }
+ return 0;
+}
+
+/**
+ * sysfs_create_file_ns - create an attribute file for an object with custom ns
+ * @kobj: object we're creating for
+ * @attr: attribute descriptor
+ * @ns: namespace the new file should belong to
+ */
+int sysfs_create_file_ns(struct kobject *kobj, const struct attribute *attr,
+ const void *ns)
+{
+ kuid_t uid;
+ kgid_t gid;
+
+ BUG_ON(!kobj || !kobj->sd || !attr);
+
+ kobject_get_ownership(kobj, &uid, &gid);
+ return sysfs_add_file_mode_ns(kobj->sd, attr, false, attr->mode,
+ uid, gid, ns);
+
+}
+EXPORT_SYMBOL_GPL(sysfs_create_file_ns);
+
+int sysfs_create_files(struct kobject *kobj, const struct attribute **ptr)
+{
+ int err = 0;
+ int i;
+
+ for (i = 0; ptr[i] && !err; i++)
+ err = sysfs_create_file(kobj, ptr[i]);
+ if (err)
+ while (--i >= 0)
+ sysfs_remove_file(kobj, ptr[i]);
+ return err;
+}
+EXPORT_SYMBOL_GPL(sysfs_create_files);
+
+/**
+ * sysfs_add_file_to_group - add an attribute file to a pre-existing group.
+ * @kobj: object we're acting for.
+ * @attr: attribute descriptor.
+ * @group: group name.
+ */
+int sysfs_add_file_to_group(struct kobject *kobj,
+ const struct attribute *attr, const char *group)
+{
+ struct kernfs_node *parent;
+ kuid_t uid;
+ kgid_t gid;
+ int error;
+
+ if (group) {
+ parent = kernfs_find_and_get(kobj->sd, group);
+ } else {
+ parent = kobj->sd;
+ kernfs_get(parent);
+ }
+
+ if (!parent)
+ return -ENOENT;
+
+ kobject_get_ownership(kobj, &uid, &gid);
+ error = sysfs_add_file_mode_ns(parent, attr, false,
+ attr->mode, uid, gid, NULL);
+ kernfs_put(parent);
+
+ return error;
+}
+EXPORT_SYMBOL_GPL(sysfs_add_file_to_group);
+
+/**
+ * sysfs_chmod_file - update the modified mode value on an object attribute.
+ * @kobj: object we're acting for.
+ * @attr: attribute descriptor.
+ * @mode: file permissions.
+ *
+ */
+int sysfs_chmod_file(struct kobject *kobj, const struct attribute *attr,
+ umode_t mode)
+{
+ struct kernfs_node *kn;
+ struct iattr newattrs;
+ int rc;
+
+ kn = kernfs_find_and_get(kobj->sd, attr->name);
+ if (!kn)
+ return -ENOENT;
+
+ newattrs.ia_mode = (mode & S_IALLUGO) | (kn->mode & ~S_IALLUGO);
+ newattrs.ia_valid = ATTR_MODE;
+
+ rc = kernfs_setattr(kn, &newattrs);
+
+ kernfs_put(kn);
+ return rc;
+}
+EXPORT_SYMBOL_GPL(sysfs_chmod_file);
+
+/**
+ * sysfs_break_active_protection - break "active" protection
+ * @kobj: The kernel object @attr is associated with.
+ * @attr: The attribute to break the "active" protection for.
+ *
+ * With sysfs, just like kernfs, deletion of an attribute is postponed until
+ * all active .show() and .store() callbacks have finished unless this function
+ * is called. Hence this function is useful in methods that implement self
+ * deletion.
+ */
+struct kernfs_node *sysfs_break_active_protection(struct kobject *kobj,
+ const struct attribute *attr)
+{
+ struct kernfs_node *kn;
+
+ kobject_get(kobj);
+ kn = kernfs_find_and_get(kobj->sd, attr->name);
+ if (kn)
+ kernfs_break_active_protection(kn);
+ return kn;
+}
+EXPORT_SYMBOL_GPL(sysfs_break_active_protection);
+
+/**
+ * sysfs_unbreak_active_protection - restore "active" protection
+ * @kn: Pointer returned by sysfs_break_active_protection().
+ *
+ * Undo the effects of sysfs_break_active_protection(). Since this function
+ * calls kernfs_put() on the kernfs node that corresponds to the 'attr'
+ * argument passed to sysfs_break_active_protection() that attribute may have
+ * been removed between the sysfs_break_active_protection() and
+ * sysfs_unbreak_active_protection() calls, it is not safe to access @kn after
+ * this function has returned.
+ */
+void sysfs_unbreak_active_protection(struct kernfs_node *kn)
+{
+ struct kobject *kobj = kn->parent->priv;
+
+ kernfs_unbreak_active_protection(kn);
+ kernfs_put(kn);
+ kobject_put(kobj);
+}
+EXPORT_SYMBOL_GPL(sysfs_unbreak_active_protection);
+
+/**
+ * sysfs_remove_file_ns - remove an object attribute with a custom ns tag
+ * @kobj: object we're acting for
+ * @attr: attribute descriptor
+ * @ns: namespace tag of the file to remove
+ *
+ * Hash the attribute name and namespace tag and kill the victim.
+ */
+void sysfs_remove_file_ns(struct kobject *kobj, const struct attribute *attr,
+ const void *ns)
+{
+ struct kernfs_node *parent = kobj->sd;
+
+ kernfs_remove_by_name_ns(parent, attr->name, ns);
+}
+EXPORT_SYMBOL_GPL(sysfs_remove_file_ns);
+
+/**
+ * sysfs_remove_file_self - remove an object attribute from its own method
+ * @kobj: object we're acting for
+ * @attr: attribute descriptor
+ *
+ * See kernfs_remove_self() for details.
+ */
+bool sysfs_remove_file_self(struct kobject *kobj, const struct attribute *attr)
+{
+ struct kernfs_node *parent = kobj->sd;
+ struct kernfs_node *kn;
+ bool ret;
+
+ kn = kernfs_find_and_get(parent, attr->name);
+ if (WARN_ON_ONCE(!kn))
+ return false;
+
+ ret = kernfs_remove_self(kn);
+
+ kernfs_put(kn);
+ return ret;
+}
+
+void sysfs_remove_files(struct kobject *kobj, const struct attribute **ptr)
+{
+ int i;
+ for (i = 0; ptr[i]; i++)
+ sysfs_remove_file(kobj, ptr[i]);
+}
+EXPORT_SYMBOL_GPL(sysfs_remove_files);
+
+/**
+ * sysfs_remove_file_from_group - remove an attribute file from a group.
+ * @kobj: object we're acting for.
+ * @attr: attribute descriptor.
+ * @group: group name.
+ */
+void sysfs_remove_file_from_group(struct kobject *kobj,
+ const struct attribute *attr, const char *group)
+{
+ struct kernfs_node *parent;
+
+ if (group) {
+ parent = kernfs_find_and_get(kobj->sd, group);
+ } else {
+ parent = kobj->sd;
+ kernfs_get(parent);
+ }
+
+ if (parent) {
+ kernfs_remove_by_name(parent, attr->name);
+ kernfs_put(parent);
+ }
+}
+EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group);
+
+/**
+ * sysfs_create_bin_file - create binary file for object.
+ * @kobj: object.
+ * @attr: attribute descriptor.
+ */
+int sysfs_create_bin_file(struct kobject *kobj,
+ const struct bin_attribute *attr)
+{
+ kuid_t uid;
+ kgid_t gid;
+
+ BUG_ON(!kobj || !kobj->sd || !attr);
+
+ kobject_get_ownership(kobj, &uid, &gid);
+ return sysfs_add_file_mode_ns(kobj->sd, &attr->attr, true,
+ attr->attr.mode, uid, gid, NULL);
+}
+EXPORT_SYMBOL_GPL(sysfs_create_bin_file);
+
+/**
+ * sysfs_remove_bin_file - remove binary file for object.
+ * @kobj: object.
+ * @attr: attribute descriptor.
+ */
+void sysfs_remove_bin_file(struct kobject *kobj,
+ const struct bin_attribute *attr)
+{
+ kernfs_remove_by_name(kobj->sd, attr->attr.name);
+}
+EXPORT_SYMBOL_GPL(sysfs_remove_bin_file);
diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c
new file mode 100644
index 0000000..1eb2d63
--- /dev/null
+++ b/fs/sysfs/group.c
@@ -0,0 +1,434 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * fs/sysfs/group.c - Operations for adding/removing multiple files at once.
+ *
+ * Copyright (c) 2003 Patrick Mochel
+ * Copyright (c) 2003 Open Source Development Lab
+ * Copyright (c) 2013 Greg Kroah-Hartman
+ * Copyright (c) 2013 The Linux Foundation
+ */
+
+#include <linux/kobject.h>
+#include <linux/module.h>
+#include <linux/dcache.h>
+#include <linux/namei.h>
+#include <linux/err.h>
+#include "sysfs.h"
+
+
+static void remove_files(struct kernfs_node *parent,
+ const struct attribute_group *grp)
+{
+ struct attribute *const *attr;
+ struct bin_attribute *const *bin_attr;
+
+ if (grp->attrs)
+ for (attr = grp->attrs; *attr; attr++)
+ kernfs_remove_by_name(parent, (*attr)->name);
+ if (grp->bin_attrs)
+ for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++)
+ kernfs_remove_by_name(parent, (*bin_attr)->attr.name);
+}
+
+static int create_files(struct kernfs_node *parent, struct kobject *kobj,
+ kuid_t uid, kgid_t gid,
+ const struct attribute_group *grp, int update)
+{
+ struct attribute *const *attr;
+ struct bin_attribute *const *bin_attr;
+ int error = 0, i;
+
+ if (grp->attrs) {
+ for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++) {
+ umode_t mode = (*attr)->mode;
+
+ /*
+ * In update mode, we're changing the permissions or
+ * visibility. Do this by first removing then
+ * re-adding (if required) the file.
+ */
+ if (update)
+ kernfs_remove_by_name(parent, (*attr)->name);
+ if (grp->is_visible) {
+ mode = grp->is_visible(kobj, *attr, i);
+ if (!mode)
+ continue;
+ }
+
+ WARN(mode & ~(SYSFS_PREALLOC | 0664),
+ "Attribute %s: Invalid permissions 0%o\n",
+ (*attr)->name, mode);
+
+ mode &= SYSFS_PREALLOC | 0664;
+ error = sysfs_add_file_mode_ns(parent, *attr, false,
+ mode, uid, gid, NULL);
+ if (unlikely(error))
+ break;
+ }
+ if (error) {
+ remove_files(parent, grp);
+ goto exit;
+ }
+ }
+
+ if (grp->bin_attrs) {
+ for (i = 0, bin_attr = grp->bin_attrs; *bin_attr; i++, bin_attr++) {
+ umode_t mode = (*bin_attr)->attr.mode;
+
+ if (update)
+ kernfs_remove_by_name(parent,
+ (*bin_attr)->attr.name);
+ if (grp->is_bin_visible) {
+ mode = grp->is_bin_visible(kobj, *bin_attr, i);
+ if (!mode)
+ continue;
+ }
+
+ WARN(mode & ~(SYSFS_PREALLOC | 0664),
+ "Attribute %s: Invalid permissions 0%o\n",
+ (*bin_attr)->attr.name, mode);
+
+ mode &= SYSFS_PREALLOC | 0664;
+ error = sysfs_add_file_mode_ns(parent,
+ &(*bin_attr)->attr, true,
+ mode,
+ uid, gid, NULL);
+ if (error)
+ break;
+ }
+ if (error)
+ remove_files(parent, grp);
+ }
+exit:
+ return error;
+}
+
+
+static int internal_create_group(struct kobject *kobj, int update,
+ const struct attribute_group *grp)
+{
+ struct kernfs_node *kn;
+ kuid_t uid;
+ kgid_t gid;
+ int error;
+
+ BUG_ON(!kobj || (!update && !kobj->sd));
+
+ /* Updates may happen before the object has been instantiated */
+ if (unlikely(update && !kobj->sd))
+ return -EINVAL;
+ if (!grp->attrs && !grp->bin_attrs) {
+ WARN(1, "sysfs: (bin_)attrs not set by subsystem for group: %s/%s\n",
+ kobj->name, grp->name ?: "");
+ return -EINVAL;
+ }
+ kobject_get_ownership(kobj, &uid, &gid);
+ if (grp->name) {
+ if (update) {
+ kn = kernfs_find_and_get(kobj->sd, grp->name);
+ if (!kn) {
+ pr_warn("Can't update unknown attr grp name: %s/%s\n",
+ kobj->name, grp->name);
+ return -EINVAL;
+ }
+ } else {
+ kn = kernfs_create_dir_ns(kobj->sd, grp->name,
+ S_IRWXU | S_IRUGO | S_IXUGO,
+ uid, gid, kobj, NULL);
+ if (IS_ERR(kn)) {
+ if (PTR_ERR(kn) == -EEXIST)
+ sysfs_warn_dup(kobj->sd, grp->name);
+ return PTR_ERR(kn);
+ }
+ }
+ } else
+ kn = kobj->sd;
+ kernfs_get(kn);
+ error = create_files(kn, kobj, uid, gid, grp, update);
+ if (error) {
+ if (grp->name)
+ kernfs_remove(kn);
+ }
+ kernfs_put(kn);
+
+ if (grp->name && update)
+ kernfs_put(kn);
+
+ return error;
+}
+
+/**
+ * sysfs_create_group - given a directory kobject, create an attribute group
+ * @kobj: The kobject to create the group on
+ * @grp: The attribute group to create
+ *
+ * This function creates a group for the first time. It will explicitly
+ * warn and error if any of the attribute files being created already exist.
+ *
+ * Returns 0 on success or error code on failure.
+ */
+int sysfs_create_group(struct kobject *kobj,
+ const struct attribute_group *grp)
+{
+ return internal_create_group(kobj, 0, grp);
+}
+EXPORT_SYMBOL_GPL(sysfs_create_group);
+
+/**
+ * sysfs_create_groups - given a directory kobject, create a bunch of attribute groups
+ * @kobj: The kobject to create the group on
+ * @groups: The attribute groups to create, NULL terminated
+ *
+ * This function creates a bunch of attribute groups. If an error occurs when
+ * creating a group, all previously created groups will be removed, unwinding
+ * everything back to the original state when this function was called.
+ * It will explicitly warn and error if any of the attribute files being
+ * created already exist.
+ *
+ * Returns 0 on success or error code from sysfs_create_group on failure.
+ */
+int sysfs_create_groups(struct kobject *kobj,
+ const struct attribute_group **groups)
+{
+ int error = 0;
+ int i;
+
+ if (!groups)
+ return 0;
+
+ for (i = 0; groups[i]; i++) {
+ error = sysfs_create_group(kobj, groups[i]);
+ if (error) {
+ while (--i >= 0)
+ sysfs_remove_group(kobj, groups[i]);
+ break;
+ }
+ }
+ return error;
+}
+EXPORT_SYMBOL_GPL(sysfs_create_groups);
+
+/**
+ * sysfs_update_group - given a directory kobject, update an attribute group
+ * @kobj: The kobject to update the group on
+ * @grp: The attribute group to update
+ *
+ * This function updates an attribute group. Unlike
+ * sysfs_create_group(), it will explicitly not warn or error if any
+ * of the attribute files being created already exist. Furthermore,
+ * if the visibility of the files has changed through the is_visible()
+ * callback, it will update the permissions and add or remove the
+ * relevant files. Changing a group's name (subdirectory name under
+ * kobj's directory in sysfs) is not allowed.
+ *
+ * The primary use for this function is to call it after making a change
+ * that affects group visibility.
+ *
+ * Returns 0 on success or error code on failure.
+ */
+int sysfs_update_group(struct kobject *kobj,
+ const struct attribute_group *grp)
+{
+ return internal_create_group(kobj, 1, grp);
+}
+EXPORT_SYMBOL_GPL(sysfs_update_group);
+
+/**
+ * sysfs_remove_group: remove a group from a kobject
+ * @kobj: kobject to remove the group from
+ * @grp: group to remove
+ *
+ * This function removes a group of attributes from a kobject. The attributes
+ * previously have to have been created for this group, otherwise it will fail.
+ */
+void sysfs_remove_group(struct kobject *kobj,
+ const struct attribute_group *grp)
+{
+ struct kernfs_node *parent = kobj->sd;
+ struct kernfs_node *kn;
+
+ if (grp->name) {
+ kn = kernfs_find_and_get(parent, grp->name);
+ if (!kn) {
+ WARN(!kn, KERN_WARNING
+ "sysfs group '%s' not found for kobject '%s'\n",
+ grp->name, kobject_name(kobj));
+ return;
+ }
+ } else {
+ kn = parent;
+ kernfs_get(kn);
+ }
+
+ remove_files(kn, grp);
+ if (grp->name)
+ kernfs_remove(kn);
+
+ kernfs_put(kn);
+}
+EXPORT_SYMBOL_GPL(sysfs_remove_group);
+
+/**
+ * sysfs_remove_groups - remove a list of groups
+ *
+ * @kobj: The kobject for the groups to be removed from
+ * @groups: NULL terminated list of groups to be removed
+ *
+ * If groups is not NULL, remove the specified groups from the kobject.
+ */
+void sysfs_remove_groups(struct kobject *kobj,
+ const struct attribute_group **groups)
+{
+ int i;
+
+ if (!groups)
+ return;
+ for (i = 0; groups[i]; i++)
+ sysfs_remove_group(kobj, groups[i]);
+}
+EXPORT_SYMBOL_GPL(sysfs_remove_groups);
+
+/**
+ * sysfs_merge_group - merge files into a pre-existing attribute group.
+ * @kobj: The kobject containing the group.
+ * @grp: The files to create and the attribute group they belong to.
+ *
+ * This function returns an error if the group doesn't exist or any of the
+ * files already exist in that group, in which case none of the new files
+ * are created.
+ */
+int sysfs_merge_group(struct kobject *kobj,
+ const struct attribute_group *grp)
+{
+ struct kernfs_node *parent;
+ kuid_t uid;
+ kgid_t gid;
+ int error = 0;
+ struct attribute *const *attr;
+ int i;
+
+ parent = kernfs_find_and_get(kobj->sd, grp->name);
+ if (!parent)
+ return -ENOENT;
+
+ kobject_get_ownership(kobj, &uid, &gid);
+
+ for ((i = 0, attr = grp->attrs); *attr && !error; (++i, ++attr))
+ error = sysfs_add_file_mode_ns(parent, *attr, false,
+ (*attr)->mode, uid, gid, NULL);
+ if (error) {
+ while (--i >= 0)
+ kernfs_remove_by_name(parent, (*--attr)->name);
+ }
+ kernfs_put(parent);
+
+ return error;
+}
+EXPORT_SYMBOL_GPL(sysfs_merge_group);
+
+/**
+ * sysfs_unmerge_group - remove files from a pre-existing attribute group.
+ * @kobj: The kobject containing the group.
+ * @grp: The files to remove and the attribute group they belong to.
+ */
+void sysfs_unmerge_group(struct kobject *kobj,
+ const struct attribute_group *grp)
+{
+ struct kernfs_node *parent;
+ struct attribute *const *attr;
+
+ parent = kernfs_find_and_get(kobj->sd, grp->name);
+ if (parent) {
+ for (attr = grp->attrs; *attr; ++attr)
+ kernfs_remove_by_name(parent, (*attr)->name);
+ kernfs_put(parent);
+ }
+}
+EXPORT_SYMBOL_GPL(sysfs_unmerge_group);
+
+/**
+ * sysfs_add_link_to_group - add a symlink to an attribute group.
+ * @kobj: The kobject containing the group.
+ * @group_name: The name of the group.
+ * @target: The target kobject of the symlink to create.
+ * @link_name: The name of the symlink to create.
+ */
+int sysfs_add_link_to_group(struct kobject *kobj, const char *group_name,
+ struct kobject *target, const char *link_name)
+{
+ struct kernfs_node *parent;
+ int error = 0;
+
+ parent = kernfs_find_and_get(kobj->sd, group_name);
+ if (!parent)
+ return -ENOENT;
+
+ error = sysfs_create_link_sd(parent, target, link_name);
+ kernfs_put(parent);
+
+ return error;
+}
+EXPORT_SYMBOL_GPL(sysfs_add_link_to_group);
+
+/**
+ * sysfs_remove_link_from_group - remove a symlink from an attribute group.
+ * @kobj: The kobject containing the group.
+ * @group_name: The name of the group.
+ * @link_name: The name of the symlink to remove.
+ */
+void sysfs_remove_link_from_group(struct kobject *kobj, const char *group_name,
+ const char *link_name)
+{
+ struct kernfs_node *parent;
+
+ parent = kernfs_find_and_get(kobj->sd, group_name);
+ if (parent) {
+ kernfs_remove_by_name(parent, link_name);
+ kernfs_put(parent);
+ }
+}
+EXPORT_SYMBOL_GPL(sysfs_remove_link_from_group);
+
+/**
+ * __compat_only_sysfs_link_entry_to_kobj - add a symlink to a kobject pointing
+ * to a group or an attribute
+ * @kobj: The kobject containing the group.
+ * @target_kobj: The target kobject.
+ * @target_name: The name of the target group or attribute.
+ */
+int __compat_only_sysfs_link_entry_to_kobj(struct kobject *kobj,
+ struct kobject *target_kobj,
+ const char *target_name)
+{
+ struct kernfs_node *target;
+ struct kernfs_node *entry;
+ struct kernfs_node *link;
+
+ /*
+ * We don't own @target_kobj and it may be removed at any time.
+ * Synchronize using sysfs_symlink_target_lock. See sysfs_remove_dir()
+ * for details.
+ */
+ spin_lock(&sysfs_symlink_target_lock);
+ target = target_kobj->sd;
+ if (target)
+ kernfs_get(target);
+ spin_unlock(&sysfs_symlink_target_lock);
+ if (!target)
+ return -ENOENT;
+
+ entry = kernfs_find_and_get(target_kobj->sd, target_name);
+ if (!entry) {
+ kernfs_put(target);
+ return -ENOENT;
+ }
+
+ link = kernfs_create_link(kobj->sd, target_name, entry);
+ if (IS_ERR(link) && PTR_ERR(link) == -EEXIST)
+ sysfs_warn_dup(kobj->sd, target_name);
+
+ kernfs_put(entry);
+ kernfs_put(target);
+ return PTR_ERR_OR_ZERO(link);
+}
+EXPORT_SYMBOL_GPL(__compat_only_sysfs_link_entry_to_kobj);
diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c
new file mode 100644
index 0000000..92682fc
--- /dev/null
+++ b/fs/sysfs/mount.c
@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * fs/sysfs/symlink.c - operations for initializing and mounting sysfs
+ *
+ * Copyright (c) 2001-3 Patrick Mochel
+ * Copyright (c) 2007 SUSE Linux Products GmbH
+ * Copyright (c) 2007 Tejun Heo <teheo@suse.de>
+ *
+ * Please see Documentation/filesystems/sysfs.txt for more information.
+ */
+
+#include <linux/fs.h>
+#include <linux/magic.h>
+#include <linux/mount.h>
+#include <linux/init.h>
+#include <linux/user_namespace.h>
+
+#include "sysfs.h"
+
+static struct kernfs_root *sysfs_root;
+struct kernfs_node *sysfs_root_kn;
+
+static struct dentry *sysfs_mount(struct file_system_type *fs_type,
+ int flags, const char *dev_name, void *data)
+{
+ struct dentry *root;
+ void *ns;
+ bool new_sb = false;
+
+ if (!(flags & SB_KERNMOUNT)) {
+ if (!kobj_ns_current_may_mount(KOBJ_NS_TYPE_NET))
+ return ERR_PTR(-EPERM);
+ }
+
+ ns = kobj_ns_grab_current(KOBJ_NS_TYPE_NET);
+ root = kernfs_mount_ns(fs_type, flags, sysfs_root,
+ SYSFS_MAGIC, &new_sb, ns);
+ if (!new_sb)
+ kobj_ns_drop(KOBJ_NS_TYPE_NET, ns);
+ else if (!IS_ERR(root))
+ root->d_sb->s_iflags |= SB_I_USERNS_VISIBLE;
+
+ return root;
+}
+
+static void sysfs_kill_sb(struct super_block *sb)
+{
+ void *ns = (void *)kernfs_super_ns(sb);
+
+ kernfs_kill_sb(sb);
+ kobj_ns_drop(KOBJ_NS_TYPE_NET, ns);
+}
+
+static struct file_system_type sysfs_fs_type = {
+ .name = "sysfs",
+ .mount = sysfs_mount,
+ .kill_sb = sysfs_kill_sb,
+ .fs_flags = FS_USERNS_MOUNT,
+};
+
+int __init sysfs_init(void)
+{
+ int err;
+
+ sysfs_root = kernfs_create_root(NULL, KERNFS_ROOT_EXTRA_OPEN_PERM_CHECK,
+ NULL);
+ if (IS_ERR(sysfs_root))
+ return PTR_ERR(sysfs_root);
+
+ sysfs_root_kn = sysfs_root->kn;
+
+ err = register_filesystem(&sysfs_fs_type);
+ if (err) {
+ kernfs_destroy_root(sysfs_root);
+ return err;
+ }
+
+ return 0;
+}
diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c
new file mode 100644
index 0000000..215c225
--- /dev/null
+++ b/fs/sysfs/symlink.c
@@ -0,0 +1,197 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * fs/sysfs/symlink.c - sysfs symlink implementation
+ *
+ * Copyright (c) 2001-3 Patrick Mochel
+ * Copyright (c) 2007 SUSE Linux Products GmbH
+ * Copyright (c) 2007 Tejun Heo <teheo@suse.de>
+ *
+ * Please see Documentation/filesystems/sysfs.txt for more information.
+ */
+
+#include <linux/fs.h>
+#include <linux/module.h>
+#include <linux/kobject.h>
+#include <linux/mutex.h>
+#include <linux/security.h>
+
+#include "sysfs.h"
+
+static int sysfs_do_create_link_sd(struct kernfs_node *parent,
+ struct kobject *target_kobj,
+ const char *name, int warn)
+{
+ struct kernfs_node *kn, *target = NULL;
+
+ BUG_ON(!name || !parent);
+
+ /*
+ * We don't own @target_kobj and it may be removed at any time.
+ * Synchronize using sysfs_symlink_target_lock. See
+ * sysfs_remove_dir() for details.
+ */
+ spin_lock(&sysfs_symlink_target_lock);
+ if (target_kobj->sd) {
+ target = target_kobj->sd;
+ kernfs_get(target);
+ }
+ spin_unlock(&sysfs_symlink_target_lock);
+
+ if (!target)
+ return -ENOENT;
+
+ kn = kernfs_create_link(parent, name, target);
+ kernfs_put(target);
+
+ if (!IS_ERR(kn))
+ return 0;
+
+ if (warn && PTR_ERR(kn) == -EEXIST)
+ sysfs_warn_dup(parent, name);
+ return PTR_ERR(kn);
+}
+
+/**
+ * sysfs_create_link_sd - create symlink to a given object.
+ * @kn: directory we're creating the link in.
+ * @target: object we're pointing to.
+ * @name: name of the symlink.
+ */
+int sysfs_create_link_sd(struct kernfs_node *kn, struct kobject *target,
+ const char *name)
+{
+ return sysfs_do_create_link_sd(kn, target, name, 1);
+}
+
+static int sysfs_do_create_link(struct kobject *kobj, struct kobject *target,
+ const char *name, int warn)
+{
+ struct kernfs_node *parent = NULL;
+
+ if (!kobj)
+ parent = sysfs_root_kn;
+ else
+ parent = kobj->sd;
+
+ if (!parent)
+ return -EFAULT;
+
+ return sysfs_do_create_link_sd(parent, target, name, warn);
+}
+
+/**
+ * sysfs_create_link - create symlink between two objects.
+ * @kobj: object whose directory we're creating the link in.
+ * @target: object we're pointing to.
+ * @name: name of the symlink.
+ */
+int sysfs_create_link(struct kobject *kobj, struct kobject *target,
+ const char *name)
+{
+ return sysfs_do_create_link(kobj, target, name, 1);
+}
+EXPORT_SYMBOL_GPL(sysfs_create_link);
+
+/**
+ * sysfs_create_link_nowarn - create symlink between two objects.
+ * @kobj: object whose directory we're creating the link in.
+ * @target: object we're pointing to.
+ * @name: name of the symlink.
+ *
+ * This function does the same as sysfs_create_link(), but it
+ * doesn't warn if the link already exists.
+ */
+int sysfs_create_link_nowarn(struct kobject *kobj, struct kobject *target,
+ const char *name)
+{
+ return sysfs_do_create_link(kobj, target, name, 0);
+}
+EXPORT_SYMBOL_GPL(sysfs_create_link_nowarn);
+
+/**
+ * sysfs_delete_link - remove symlink in object's directory.
+ * @kobj: object we're acting for.
+ * @targ: object we're pointing to.
+ * @name: name of the symlink to remove.
+ *
+ * Unlike sysfs_remove_link sysfs_delete_link has enough information
+ * to successfully delete symlinks in tagged directories.
+ */
+void sysfs_delete_link(struct kobject *kobj, struct kobject *targ,
+ const char *name)
+{
+ const void *ns = NULL;
+
+ /*
+ * We don't own @target and it may be removed at any time.
+ * Synchronize using sysfs_symlink_target_lock. See
+ * sysfs_remove_dir() for details.
+ */
+ spin_lock(&sysfs_symlink_target_lock);
+ if (targ->sd && kernfs_ns_enabled(kobj->sd))
+ ns = targ->sd->ns;
+ spin_unlock(&sysfs_symlink_target_lock);
+ kernfs_remove_by_name_ns(kobj->sd, name, ns);
+}
+
+/**
+ * sysfs_remove_link - remove symlink in object's directory.
+ * @kobj: object we're acting for.
+ * @name: name of the symlink to remove.
+ */
+void sysfs_remove_link(struct kobject *kobj, const char *name)
+{
+ struct kernfs_node *parent = NULL;
+
+ if (!kobj)
+ parent = sysfs_root_kn;
+ else
+ parent = kobj->sd;
+
+ kernfs_remove_by_name(parent, name);
+}
+EXPORT_SYMBOL_GPL(sysfs_remove_link);
+
+/**
+ * sysfs_rename_link_ns - rename symlink in object's directory.
+ * @kobj: object we're acting for.
+ * @targ: object we're pointing to.
+ * @old: previous name of the symlink.
+ * @new: new name of the symlink.
+ * @new_ns: new namespace of the symlink.
+ *
+ * A helper function for the common rename symlink idiom.
+ */
+int sysfs_rename_link_ns(struct kobject *kobj, struct kobject *targ,
+ const char *old, const char *new, const void *new_ns)
+{
+ struct kernfs_node *parent, *kn = NULL;
+ const void *old_ns = NULL;
+ int result;
+
+ if (!kobj)
+ parent = sysfs_root_kn;
+ else
+ parent = kobj->sd;
+
+ if (targ->sd)
+ old_ns = targ->sd->ns;
+
+ result = -ENOENT;
+ kn = kernfs_find_and_get_ns(parent, old, old_ns);
+ if (!kn)
+ goto out;
+
+ result = -EINVAL;
+ if (kernfs_type(kn) != KERNFS_LINK)
+ goto out;
+ if (kn->symlink.target_kn->priv != targ)
+ goto out;
+
+ result = kernfs_rename_ns(kn, parent, new, new_ns);
+
+out:
+ kernfs_put(kn);
+ return result;
+}
+EXPORT_SYMBOL_GPL(sysfs_rename_link_ns);
diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
new file mode 100644
index 0000000..0050cc0
--- /dev/null
+++ b/fs/sysfs/sysfs.h
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * fs/sysfs/sysfs.h - sysfs internal header file
+ *
+ * Copyright (c) 2001-3 Patrick Mochel
+ * Copyright (c) 2007 SUSE Linux Products GmbH
+ * Copyright (c) 2007 Tejun Heo <teheo@suse.de>
+ */
+
+#ifndef __SYSFS_INTERNAL_H
+#define __SYSFS_INTERNAL_H
+
+#include <linux/sysfs.h>
+
+/*
+ * mount.c
+ */
+extern struct kernfs_node *sysfs_root_kn;
+
+/*
+ * dir.c
+ */
+extern spinlock_t sysfs_symlink_target_lock;
+
+void sysfs_warn_dup(struct kernfs_node *parent, const char *name);
+
+/*
+ * file.c
+ */
+int sysfs_add_file_mode_ns(struct kernfs_node *parent,
+ const struct attribute *attr, bool is_bin,
+ umode_t amode, kuid_t uid, kgid_t gid,
+ const void *ns);
+
+/*
+ * symlink.c
+ */
+int sysfs_create_link_sd(struct kernfs_node *kn, struct kobject *target,
+ const char *name);
+
+#endif /* __SYSFS_INTERNAL_H */