mirror of
https://github.com/FEX-Emu/linux.git
synced 2024-12-25 02:48:21 +00:00
784aae735d
Implement simple read-only sysfs entry for device-mapper block device. This patch adds a simple sysfs directory named "dm" under block device properties and implements - name attribute (string containing mapped device name) - uuid attribute (string containing UUID, or empty string if not set) The kobject is embedded in mapped_device struct, so no additional memory allocation is needed for initializing sysfs entry. During the processing of sysfs attribute we need to lock mapped device which is done by a new function dm_get_from_kobj, which returns the md associated with kobject and increases the usage count. Each 'show attribute' function is responsible for its own locking. Signed-off-by: Milan Broz <mbroz@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
100 lines
2.0 KiB
C
100 lines
2.0 KiB
C
/*
|
|
* Copyright (C) 2008 Red Hat, Inc. All rights reserved.
|
|
*
|
|
* This file is released under the GPL.
|
|
*/
|
|
|
|
#include <linux/sysfs.h>
|
|
#include <linux/dm-ioctl.h>
|
|
#include "dm.h"
|
|
|
|
struct dm_sysfs_attr {
|
|
struct attribute attr;
|
|
ssize_t (*show)(struct mapped_device *, char *);
|
|
ssize_t (*store)(struct mapped_device *, char *);
|
|
};
|
|
|
|
#define DM_ATTR_RO(_name) \
|
|
struct dm_sysfs_attr dm_attr_##_name = \
|
|
__ATTR(_name, S_IRUGO, dm_attr_##_name##_show, NULL)
|
|
|
|
static ssize_t dm_attr_show(struct kobject *kobj, struct attribute *attr,
|
|
char *page)
|
|
{
|
|
struct dm_sysfs_attr *dm_attr;
|
|
struct mapped_device *md;
|
|
ssize_t ret;
|
|
|
|
dm_attr = container_of(attr, struct dm_sysfs_attr, attr);
|
|
if (!dm_attr->show)
|
|
return -EIO;
|
|
|
|
md = dm_get_from_kobject(kobj);
|
|
if (!md)
|
|
return -EINVAL;
|
|
|
|
ret = dm_attr->show(md, page);
|
|
dm_put(md);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static ssize_t dm_attr_name_show(struct mapped_device *md, char *buf)
|
|
{
|
|
if (dm_copy_name_and_uuid(md, buf, NULL))
|
|
return -EIO;
|
|
|
|
strcat(buf, "\n");
|
|
return strlen(buf);
|
|
}
|
|
|
|
static ssize_t dm_attr_uuid_show(struct mapped_device *md, char *buf)
|
|
{
|
|
if (dm_copy_name_and_uuid(md, NULL, buf))
|
|
return -EIO;
|
|
|
|
strcat(buf, "\n");
|
|
return strlen(buf);
|
|
}
|
|
|
|
static DM_ATTR_RO(name);
|
|
static DM_ATTR_RO(uuid);
|
|
|
|
static struct attribute *dm_attrs[] = {
|
|
&dm_attr_name.attr,
|
|
&dm_attr_uuid.attr,
|
|
NULL,
|
|
};
|
|
|
|
static struct sysfs_ops dm_sysfs_ops = {
|
|
.show = dm_attr_show,
|
|
};
|
|
|
|
/*
|
|
* dm kobject is embedded in mapped_device structure
|
|
* no need to define release function here
|
|
*/
|
|
static struct kobj_type dm_ktype = {
|
|
.sysfs_ops = &dm_sysfs_ops,
|
|
.default_attrs = dm_attrs,
|
|
};
|
|
|
|
/*
|
|
* Initialize kobj
|
|
* because nobody using md yet, no need to call explicit dm_get/put
|
|
*/
|
|
int dm_sysfs_init(struct mapped_device *md)
|
|
{
|
|
return kobject_init_and_add(dm_kobject(md), &dm_ktype,
|
|
&disk_to_dev(dm_disk(md))->kobj,
|
|
"%s", "dm");
|
|
}
|
|
|
|
/*
|
|
* Remove kobj, called after all references removed
|
|
*/
|
|
void dm_sysfs_exit(struct mapped_device *md)
|
|
{
|
|
kobject_put(dm_kobject(md));
|
|
}
|