/* * fs/sysfs/group.c - Operations for adding/removing multiple files at once. * * Copyright (c) 2003 Patrick Mochel * Copyright (c) 2003 Open Source Development Lab * * 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 sysfs_dirent *dir_sd, struct kobject *kobj,			 const struct attribute_group *grp){	struct attribute *const* attr;	int i; 	for (i = 0, attr = grp->attrs; *attr; i++, attr++)		sysfs_hash_and_remove(dir_sd, NULL, (*attr)->name);} static int create_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,			const struct attribute_group *grp, int update){	struct attribute *const* attr;	int error = 0, i; 	for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++) {		umode_t mode = 0; 		/* in update mode, we're changing the permissions or		 * visibility.  Do this by first removing then		 * re-adding (if required) the file */		if (update)			sysfs_hash_and_remove(dir_sd, NULL, (*attr)->name);		if (grp->is_visible) {			mode = grp->is_visible(kobj, *attr, i);			if (!mode)				continue;		}		error = sysfs_add_file_mode(dir_sd, *attr, SYSFS_KOBJ_ATTR,					    (*attr)->mode | mode);		if (unlikely(error))			break;	}	if (error)		remove_files(dir_sd, kobj, grp);	return error;}  static int internal_create_group(struct kobject *kobj, int update,				 const struct attribute_group *grp){	struct sysfs_dirent *sd;	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) {		WARN(1, "sysfs: attrs not set by subsystem for group: %s/%s\n",			kobj->name, grp->name ? "" : grp->name);		return -EINVAL;	}	if (grp->name) {		error = sysfs_create_subdir(kobj, grp->name, &sd);		if (error)			return error;	} else		sd = kobj->sd;	sysfs_get(sd);	error = create_files(sd, kobj, grp, update);	if (error) {		if (grp->name)			sysfs_remove_subdir(sd);	}	sysfs_put(sd);	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);} /** * 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);}   void sysfs_remove_group(struct kobject * kobj, 			const struct attribute_group * grp){	struct sysfs_dirent *dir_sd = kobj->sd;	struct sysfs_dirent *sd; 	if (grp->name) {		sd = sysfs_get_dirent(dir_sd, NULL, grp->name);		if (!sd) {			WARN(!sd, KERN_WARNING "sysfs group %p not found for "				"kobject '%s'\n", grp, kobject_name(kobj));			return;		}	} else		sd = sysfs_get(dir_sd); 	remove_files(sd, kobj, grp);	if (grp->name)		sysfs_remove_subdir(sd); 	sysfs_put(sd);} /** * 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 sysfs_dirent *dir_sd;	int error = 0;	struct attribute *const *attr;	int i; 	dir_sd = sysfs_get_dirent(kobj->sd, NULL, grp->name);	if (!dir_sd)		return -ENOENT; 	for ((i = 0, attr = grp->attrs); *attr && !error; (++i, ++attr))		error = sysfs_add_file(dir_sd, *attr, SYSFS_KOBJ_ATTR);	if (error) {		while (--i >= 0)			sysfs_hash_and_remove(dir_sd, NULL, (*--attr)->name);	}	sysfs_put(dir_sd); 	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 sysfs_dirent *dir_sd;	struct attribute *const *attr; 	dir_sd = sysfs_get_dirent(kobj->sd, NULL, grp->name);	if (dir_sd) {		for (attr = grp->attrs; *attr; ++attr)			sysfs_hash_and_remove(dir_sd, NULL, (*attr)->name);		sysfs_put(dir_sd);	}}EXPORT_SYMBOL_GPL(sysfs_unmerge_group);  EXPORT_SYMBOL_GPL(sysfs_create_group);EXPORT_SYMBOL_GPL(sysfs_update_group);EXPORT_SYMBOL_GPL(sysfs_remove_group);