1 files changed, 354 insertions, 0 deletions
diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c
new file mode 100644
index 000000000..b400c0437
--- /dev/null
+++ b/fs/sysfs/group.c
@@ -0,0 +1,354 @@
+/*
+ * 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
+ *
+ * This file is released undert the GPL v2.
+ *
+ */
+
+#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,
+			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, NULL);
+			if (unlikely(error))
+				break;
+		}
+		if (error) {
+			remove_files(parent, grp);
+			goto exit;
+		}
+	}
+
+	if (grp->bin_attrs) {
+		for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++) {
+			if (update)
+				kernfs_remove_by_name(parent,
+						(*bin_attr)->attr.name);
+			error = sysfs_add_file_mode_ns(parent,
+					&(*bin_attr)->attr, true,
+					(*bin_attr)->attr.mode, 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;
+	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;
+	}
+	if (grp->name) {
+		kn = kernfs_create_dir(kobj->sd, grp->name,
+				       S_IRWXU | S_IRUGO | S_IXUGO, kobj);
+		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, grp, update);
+	if (error) {
+		if (grp->name)
+			kernfs_remove(kn);
+	}
+	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.
+ */
+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 error.
+ */
+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.
+ *
+ * The primary use for this function is to call it after making a change
+ * that affects group visibility.
+ *
+ * Returns 0 on success or error.
+ */
+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 %p not found for kobject '%s'\n",
+			     grp, 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;
+	int error = 0;
+	struct attribute *const *attr;
+	int i;
+
+	parent = kernfs_find_and_get(kobj->sd, grp->name);
+	if (!parent)
+		return -ENOENT;
+
+	for ((i = 0, attr = grp->attrs); *attr && !error; (++i, ++attr))
+		error = sysfs_add_file(parent, *attr, false);
+	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);