1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2008 Red Hat, Inc. All rights reserved.
4 *
5 * This file is released under the GPL.
6 */
7
8#include <linux/sysfs.h>
9#include <linux/dm-ioctl.h>
10#include "dm-core.h"
11#include "dm-rq.h"
12
13struct dm_sysfs_attr {
14	struct attribute attr;
15	ssize_t (*show)(struct mapped_device *md, char *p);
16	ssize_t (*store)(struct mapped_device *md, const char *p, size_t count);
17};
18
19#define DM_ATTR_RO(_name) \
20struct dm_sysfs_attr dm_attr_##_name = \
21	__ATTR(_name, 0444, dm_attr_##_name##_show, NULL)
22
23static ssize_t dm_attr_show(struct kobject *kobj, struct attribute *attr,
24			    char *page)
25{
26	struct dm_sysfs_attr *dm_attr;
27	struct mapped_device *md;
28	ssize_t ret;
29
30	dm_attr = container_of(attr, struct dm_sysfs_attr, attr);
31	if (!dm_attr->show)
32		return -EIO;
33
34	md = dm_get_from_kobject(kobj);
35	if (!md)
36		return -EINVAL;
37
38	ret = dm_attr->show(md, page);
39	dm_put(md);
40
41	return ret;
42}
43
44#define DM_ATTR_RW(_name) \
45struct dm_sysfs_attr dm_attr_##_name = \
46	__ATTR(_name, 0644, dm_attr_##_name##_show, dm_attr_##_name##_store)
47
48static ssize_t dm_attr_store(struct kobject *kobj, struct attribute *attr,
49			     const char *page, size_t count)
50{
51	struct dm_sysfs_attr *dm_attr;
52	struct mapped_device *md;
53	ssize_t ret;
54
55	dm_attr = container_of(attr, struct dm_sysfs_attr, attr);
56	if (!dm_attr->store)
57		return -EIO;
58
59	md = dm_get_from_kobject(kobj);
60	if (!md)
61		return -EINVAL;
62
63	ret = dm_attr->store(md, page, count);
64	dm_put(md);
65
66	return ret;
67}
68
69static ssize_t dm_attr_name_show(struct mapped_device *md, char *buf)
70{
71	if (dm_copy_name_and_uuid(md, buf, NULL))
72		return -EIO;
73
74	strcat(buf, "\n");
75	return strlen(buf);
76}
77
78static ssize_t dm_attr_uuid_show(struct mapped_device *md, char *buf)
79{
80	if (dm_copy_name_and_uuid(md, NULL, buf))
81		return -EIO;
82
83	strcat(buf, "\n");
84	return strlen(buf);
85}
86
87static ssize_t dm_attr_suspended_show(struct mapped_device *md, char *buf)
88{
89	sprintf(buf, "%d\n", dm_suspended_md(md));
90
91	return strlen(buf);
92}
93
94static ssize_t dm_attr_use_blk_mq_show(struct mapped_device *md, char *buf)
95{
96	/* Purely for userspace compatibility */
97	sprintf(buf, "%d\n", true);
98
99	return strlen(buf);
100}
101
102static DM_ATTR_RO(name);
103static DM_ATTR_RO(uuid);
104static DM_ATTR_RO(suspended);
105static DM_ATTR_RO(use_blk_mq);
106static DM_ATTR_RW(rq_based_seq_io_merge_deadline);
107
108static struct attribute *dm_attrs[] = {
109	&dm_attr_name.attr,
110	&dm_attr_uuid.attr,
111	&dm_attr_suspended.attr,
112	&dm_attr_use_blk_mq.attr,
113	&dm_attr_rq_based_seq_io_merge_deadline.attr,
114	NULL,
115};
116ATTRIBUTE_GROUPS(dm);
117
118static const struct sysfs_ops dm_sysfs_ops = {
119	.show	= dm_attr_show,
120	.store	= dm_attr_store,
121};
122
123static const struct kobj_type dm_ktype = {
124	.sysfs_ops	= &dm_sysfs_ops,
125	.default_groups	= dm_groups,
126	.release	= dm_kobject_release,
127};
128
129/*
130 * Initialize kobj
131 * because nobody using md yet, no need to call explicit dm_get/put
132 */
133int dm_sysfs_init(struct mapped_device *md)
134{
135	return kobject_init_and_add(dm_kobject(md), &dm_ktype,
136				    &disk_to_dev(dm_disk(md))->kobj,
137				    "%s", "dm");
138}
139
140/*
141 * Remove kobj, called after all references removed
142 */
143void dm_sysfs_exit(struct mapped_device *md)
144{
145	struct kobject *kobj = dm_kobject(md);
146
147	kobject_put(kobj);
148	wait_for_completion(dm_get_completion_from_kobject(kobj));
149}
150