drivers/md/dm-sysfs.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2008 Red Hat, Inc. All rights reserved.
   4  *
   5  * This file is released under the GPL.
   6  */
   7
   8 #include <linux/sysfs.h>
   9 #include <linux/dm-ioctl.h>
  10 #include "dm-core.h"
  11 #include "dm-rq.h"
  12
  13 struct dm_sysfs_attr {
  14         struct attribute attr;
  15         ssize_t (*show)(struct mapped_device *md, char *p);
  16         ssize_t (*store)(struct mapped_device *md, const char *p, size_t count);
  17 };
  18
  19 #define DM_ATTR_RO(_name) \
  20 struct dm_sysfs_attr dm_attr_##_name = \
  21         __ATTR(_name, 0444, dm_attr_##_name##_show, NULL)
  22
  23 static ssize_t dm_attr_show(struct kobject *kobj, struct attribute *attr,
  24                             char *page)
  25 {
  26         struct dm_sysfs_attr *dm_attr;
  27         struct mapped_device *md;
  28         ssize_t ret;
  29
  30         dm_attr = container_of(attr, struct dm_sysfs_attr, attr);
  31         if (!dm_attr->show)
  32                 return -EIO;
  33
  34         md = dm_get_from_kobject(kobj);
  35         if (!md)
  36                 return -EINVAL;
  37
  38         ret = dm_attr->show(md, page);
  39         dm_put(md);
  40
  41         return ret;
  42 }
  43
  44 #define DM_ATTR_RW(_name) \
  45 struct dm_sysfs_attr dm_attr_##_name = \
  46         __ATTR(_name, 0644, dm_attr_##_name##_show, dm_attr_##_name##_store)
  47
  48 static ssize_t dm_attr_store(struct kobject *kobj, struct attribute *attr,
  49                              const char *page, size_t count)
  50 {
  51         struct dm_sysfs_attr *dm_attr;
  52         struct mapped_device *md;
  53         ssize_t ret;
  54
  55         dm_attr = container_of(attr, struct dm_sysfs_attr, attr);
  56         if (!dm_attr->store)
  57                 return -EIO;
  58
  59         md = dm_get_from_kobject(kobj);
  60         if (!md)
  61                 return -EINVAL;
  62
  63         ret = dm_attr->store(md, page, count);
  64         dm_put(md);
  65
  66         return ret;
  67 }
  68
  69 static ssize_t dm_attr_name_show(struct mapped_device *md, char *buf)
  70 {
  71         if (dm_copy_name_and_uuid(md, buf, NULL))
  72                 return -EIO;
  73
  74         strcat(buf, "\n");
  75         return strlen(buf);
  76 }
  77
  78 static ssize_t dm_attr_uuid_show(struct mapped_device *md, char *buf)
  79 {
  80         if (dm_copy_name_and_uuid(md, NULL, buf))
  81                 return -EIO;
  82
  83         strcat(buf, "\n");
  84         return strlen(buf);
  85 }
  86
  87 static ssize_t dm_attr_suspended_show(struct mapped_device *md, char *buf)
  88 {
  89         sprintf(buf, "%d\n", dm_suspended_md(md));
  90
  91         return strlen(buf);
  92 }
  93
  94 static ssize_t dm_attr_use_blk_mq_show(struct mapped_device *md, char *buf)
  95 {
  96         /* Purely for userspace compatibility */
  97         sprintf(buf, "%d\n", true);
  98
  99         return strlen(buf);
 100 }
 101
 102 static DM_ATTR_RO(name);
 103 static DM_ATTR_RO(uuid);
 104 static DM_ATTR_RO(suspended);
 105 static DM_ATTR_RO(use_blk_mq);
 106 static DM_ATTR_RW(rq_based_seq_io_merge_deadline);
 107
 108 static struct attribute *dm_attrs[] = {
 109         &dm_attr_name.attr,
 110         &dm_attr_uuid.attr,
 111         &dm_attr_suspended.attr,
 112         &dm_attr_use_blk_mq.attr,
 113         &dm_attr_rq_based_seq_io_merge_deadline.attr,
 114         NULL,
 115 };
 116 ATTRIBUTE_GROUPS(dm);
 117
 118 static const struct sysfs_ops dm_sysfs_ops = {
 119         .show   = dm_attr_show,
 120         .store  = dm_attr_store,
 121 };
 122
 123 static const struct kobj_type dm_ktype = {
 124         .sysfs_ops      = &dm_sysfs_ops,
 125         .default_groups = dm_groups,
 126         .release        = dm_kobject_release,
 127 };
 128
 129 /*
 130  * Initialize kobj
 131  * because nobody using md yet, no need to call explicit dm_get/put
 132  */
 133 int dm_sysfs_init(struct mapped_device *md)
 134 {
 135         return kobject_init_and_add(dm_kobject(md), &dm_ktype,
 136                                     &disk_to_dev(dm_disk(md))->kobj,
 137                                     "%s", "dm");
 138 }
 139
 140 /*
 141  * Remove kobj, called after all references removed
 142  */
 143 void dm_sysfs_exit(struct mapped_device *md)
 144 {
 145         struct kobject *kobj = dm_kobject(md);
 146
 147         kobject_put(kobj);
 148         wait_for_completion(dm_get_completion_from_kobject(kobj));
 149 }