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 const struct sysfs_ops dm_sysfs_ops = {
  79         .show   = dm_attr_show,
  80 };
  81
  82 static void dm_kobject_release(struct kobject *kobj)
  83 {
  84         complete(dm_get_completion_from_kobject(kobj));
  85 }
  86
  87 /*
  88  * dm kobject is embedded in mapped_device structure
  89  * no need to define release function here
  90  */
  91 static struct kobj_type dm_ktype = {
  92         .sysfs_ops      = &dm_sysfs_ops,
  93         .default_attrs  = dm_attrs,
  94         .release        = dm_kobject_release,
  95 };
  96
  97 /*
  98  * Initialize kobj
  99  * because nobody using md yet, no need to call explicit dm_get/put
 100  */
 101 int dm_sysfs_init(struct mapped_device *md)
 102 {
 103         return kobject_init_and_add(dm_kobject(md), &dm_ktype,
 104                                     &disk_to_dev(dm_disk(md))->kobj,
 105                                     "%s", "dm");
 106 }
 107
 108 /*
 109  * Remove kobj, called after all references removed
 110  */
 111 void dm_sysfs_exit(struct mapped_device *md)
 112 {
 113         struct kobject *kobj = dm_kobject(md);
 114         kobject_put(kobj);
 115         wait_for_completion(dm_get_completion_from_kobject(kobj));
 116 }