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
  12 struct 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) \
  19 struct dm_sysfs_attr dm_attr_##_name = \
  20         __ATTR(_name, S_IRUGO, dm_attr_##_name##_show, NULL)
  21
  22 static 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) \
  44 struct dm_sysfs_attr dm_attr_##_name = \
  45         __ATTR(_name, S_IRUGO | S_IWUSR, dm_attr_##_name##_show, dm_attr_##_name##_store)
  46
  47 static 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
  68 static 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
  77 static 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
  86 static 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
  93 static 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
 101 static DM_ATTR_RO(name);
 102 static DM_ATTR_RO(uuid);
 103 static DM_ATTR_RO(suspended);
 104 static DM_ATTR_RO(use_blk_mq);
 105 static DM_ATTR_RW(rq_based_seq_io_merge_deadline);
 106
 107 static 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
 116 static const struct sysfs_ops dm_sysfs_ops = {
 117         .show   = dm_attr_show,
 118         .store  = dm_attr_store,
 119 };
 120
 121 static 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  */
 131 int 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  */
 141 void 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 }