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-core.h"
  10#include "dm-rq.h"
  11
  12struct 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) \
  19struct dm_sysfs_attr dm_attr_##_name = \
  20        __ATTR(_name, S_IRUGO, dm_attr_##_name##_show, NULL)
  21
  22static 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) \
  44struct dm_sysfs_attr dm_attr_##_name = \
  45        __ATTR(_name, S_IRUGO | S_IWUSR, dm_attr_##_name##_show, dm_attr_##_name##_store)
  46
  47static 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
  68static 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
  77static 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
  86static 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
  93static 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
 101static DM_ATTR_RO(name);
 102static DM_ATTR_RO(uuid);
 103static DM_ATTR_RO(suspended);
 104static DM_ATTR_RO(use_blk_mq);
 105static DM_ATTR_RW(rq_based_seq_io_merge_deadline);
 106
 107static 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
 116static const struct sysfs_ops dm_sysfs_ops = {
 117        .show   = dm_attr_show,
 118        .store  = dm_attr_store,
 119};
 120
 121static struct kobj_type dm_ktype = {
 122        .sysfs_ops      = &dm_sysfs_ops,
 123        .default_attrs  = dm_attrs,
 124        .release        = dm_kobject_release,
 125};
 126
 127/*
 128 * Initialize kobj
 129 * because nobody using md yet, no need to call explicit dm_get/put
 130 */
 131int dm_sysfs_init(struct mapped_device *md)
 132{
 133        return kobject_init_and_add(dm_kobject(md), &dm_ktype,
 134                                    &disk_to_dev(dm_disk(md))->kobj,
 135                                    "%s", "dm");
 136}
 137
 138/*
 139 * Remove kobj, called after all references removed
 140 */
 141void dm_sysfs_exit(struct mapped_device *md)
 142{
 143        struct kobject *kobj = dm_kobject(md);
 144        kobject_put(kobj);
 145        wait_for_completion(dm_get_completion_from_kobject(kobj));
 146}
 147