LXR linux/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
  11struct 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) \
  18struct dm_sysfs_attr dm_attr_##_name = \
  19        __ATTR(_name, S_IRUGO, dm_attr_##_name##_show, NULL)
  20
  21static 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) \
  43struct dm_sysfs_attr dm_attr_##_name = \
  44        __ATTR(_name, S_IRUGO | S_IWUSR, dm_attr_##_name##_show, dm_attr_##_name##_store)
  45
  46static 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
  67static 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
  76static 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
  85static 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
  92static 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
  99static DM_ATTR_RO(name);
 100static DM_ATTR_RO(uuid);
 101static DM_ATTR_RO(suspended);
 102static DM_ATTR_RO(use_blk_mq);
 103static DM_ATTR_RW(rq_based_seq_io_merge_deadline);
 104
 105static 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
 114static const struct sysfs_ops dm_sysfs_ops = {
 115        .show   = dm_attr_show,
 116        .store  = dm_attr_store,
 117};
 118
 119static 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 */
 129int 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 */
 139void 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}
 145