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