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 *, const char *, size_t count);
  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 #define DM_ATTR_RW(_name) \
  43 struct dm_sysfs_attr dm_attr_##_name = \
  44         __ATTR(_name, S_IRUGO | S_IWUSR, dm_attr_##_name##_show, dm_attr_##_name##_store)
  45
  46 static ssize_t dm_attr_store(struct kobject *kobj, struct attribute *attr,
  47                              const char *page, size_t count)
  48 {
  49         struct dm_sysfs_attr *dm_attr;
  50         struct mapped_device *md;
  51         ssize_t ret;
  52
  53         dm_attr = container_of(attr, struct dm_sysfs_attr, attr);
  54         if (!dm_attr->store)
  55                 return -EIO;
  56
  57         md = dm_get_from_kobject(kobj);
  58         if (!md)
  59                 return -EINVAL;
  60
  61         ret = dm_attr->store(md, page, count);
  62         dm_put(md);
  63
  64         return ret;
  65 }
  66
  67 static ssize_t dm_attr_name_show(struct mapped_device *md, char *buf)
  68 {
  69         if (dm_copy_name_and_uuid(md, buf, NULL))
  70                 return -EIO;
  71
  72         strcat(buf, "\n");
  73         return strlen(buf);
  74 }
  75
  76 static ssize_t dm_attr_uuid_show(struct mapped_device *md, char *buf)
  77 {
  78         if (dm_copy_name_and_uuid(md, NULL, buf))
  79                 return -EIO;
  80
  81         strcat(buf, "\n");
  82         return strlen(buf);
  83 }
  84
  85 static ssize_t dm_attr_suspended_show(struct mapped_device *md, char *buf)
  86 {
  87         sprintf(buf, "%d\n", dm_suspended_md(md));
  88
  89         return strlen(buf);
  90 }
  91
  92 static ssize_t dm_attr_use_blk_mq_show(struct mapped_device *md, char *buf)
  93 {
  94         sprintf(buf, "%d\n", dm_use_blk_mq(md));
  95
  96         return strlen(buf);
  97 }
  98
  99 static DM_ATTR_RO(name);
 100 static DM_ATTR_RO(uuid);
 101 static DM_ATTR_RO(suspended);
 102 static DM_ATTR_RO(use_blk_mq);
 103 static DM_ATTR_RW(rq_based_seq_io_merge_deadline);
 104
 105 static struct attribute *dm_attrs[] = {
 106         &dm_attr_name.attr,
 107         &dm_attr_uuid.attr,
 108         &dm_attr_suspended.attr,
 109         &dm_attr_use_blk_mq.attr,
 110         &dm_attr_rq_based_seq_io_merge_deadline.attr,
 111         NULL,
 112 };
 113
 114 static const struct sysfs_ops dm_sysfs_ops = {
 115         .show   = dm_attr_show,
 116         .store  = dm_attr_store,
 117 };
 118
 119 static struct kobj_type dm_ktype = {
 120         .sysfs_ops      = &dm_sysfs_ops,
 121         .default_attrs  = dm_attrs,
 122         .release        = dm_kobject_release,
 123 };
 124
 125 /*
 126  * Initialize kobj
 127  * because nobody using md yet, no need to call explicit dm_get/put
 128  */
 129 int dm_sysfs_init(struct mapped_device *md)
 130 {
 131         return kobject_init_and_add(dm_kobject(md), &dm_ktype,
 132                                     &disk_to_dev(dm_disk(md))->kobj,
 133                                     "%s", "dm");
 134 }
 135
 136 /*
 137  * Remove kobj, called after all references removed
 138  */
 139 void dm_sysfs_exit(struct mapped_device *md)
 140 {
 141         struct kobject *kobj = dm_kobject(md);
 142         kobject_put(kobj);
 143         wait_for_completion(dm_get_completion_from_kobject(kobj));
 144 }