virtio: Add memory statistics reporting to the balloon driver (V4)
[linux-2.6.git] / drivers / md / dm-sysfs.c
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.h"
10
11 struct dm_sysfs_attr {
12         struct attribute attr;
13         ssize_t (*show)(struct mapped_device *, char *);
14         ssize_t (*store)(struct mapped_device *, char *);
15 };
16
17 #define DM_ATTR_RO(_name) \
18 struct dm_sysfs_attr dm_attr_##_name = \
19         __ATTR(_name, S_IRUGO, dm_attr_##_name##_show, NULL)
20
21 static ssize_t dm_attr_show(struct kobject *kobj, struct attribute *attr,
22                             char *page)
23 {
24         struct dm_sysfs_attr *dm_attr;
25         struct mapped_device *md;
26         ssize_t ret;
27
28         dm_attr = container_of(attr, struct dm_sysfs_attr, attr);
29         if (!dm_attr->show)
30                 return -EIO;
31
32         md = dm_get_from_kobject(kobj);
33         if (!md)
34                 return -EINVAL;
35
36         ret = dm_attr->show(md, page);
37         dm_put(md);
38
39         return ret;
40 }
41
42 static ssize_t dm_attr_name_show(struct mapped_device *md, char *buf)
43 {
44         if (dm_copy_name_and_uuid(md, buf, NULL))
45                 return -EIO;
46
47         strcat(buf, "\n");
48         return strlen(buf);
49 }
50
51 static ssize_t dm_attr_uuid_show(struct mapped_device *md, char *buf)
52 {
53         if (dm_copy_name_and_uuid(md, NULL, buf))
54                 return -EIO;
55
56         strcat(buf, "\n");
57         return strlen(buf);
58 }
59
60 static ssize_t dm_attr_suspended_show(struct mapped_device *md, char *buf)
61 {
62         sprintf(buf, "%d\n", dm_suspended_md(md));
63
64         return strlen(buf);
65 }
66
67 static DM_ATTR_RO(name);
68 static DM_ATTR_RO(uuid);
69 static DM_ATTR_RO(suspended);
70
71 static struct attribute *dm_attrs[] = {
72         &dm_attr_name.attr,
73         &dm_attr_uuid.attr,
74         &dm_attr_suspended.attr,
75         NULL,
76 };
77
78 static struct sysfs_ops dm_sysfs_ops = {
79         .show   = dm_attr_show,
80 };
81
82 /*
83  * dm kobject is embedded in mapped_device structure
84  * no need to define release function here
85  */
86 static struct kobj_type dm_ktype = {
87         .sysfs_ops      = &dm_sysfs_ops,
88         .default_attrs  = dm_attrs,
89 };
90
91 /*
92  * Initialize kobj
93  * because nobody using md yet, no need to call explicit dm_get/put
94  */
95 int dm_sysfs_init(struct mapped_device *md)
96 {
97         return kobject_init_and_add(dm_kobject(md), &dm_ktype,
98                                     &disk_to_dev(dm_disk(md))->kobj,
99                                     "%s", "dm");
100 }
101
102 /*
103  * Remove kobj, called after all references removed
104  */
105 void dm_sysfs_exit(struct mapped_device *md)
106 {
107         kobject_put(dm_kobject(md));
108 }