v4.19.13 snapshot.
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);