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/*
* 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++) {
mode_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->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, create an attribute group
* @kobj: The kobject to create the group on
* @grp: The attribute group to create
*
* 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);
}
EXPORT_SYMBOL_GPL(sysfs_create_group);
EXPORT_SYMBOL_GPL(sysfs_update_group);
EXPORT_SYMBOL_GPL(sysfs_remove_group);
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