drivers/block/rnbd/rnbd-srv-sysfs.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * RDMA Network Block Driver
   4  *
   5  * Copyright (c) 2014 - 2018 ProfitBricks GmbH. All rights reserved.
   6  * Copyright (c) 2018 - 2019 1&1 IONOS Cloud GmbH. All rights reserved.
   7  * Copyright (c) 2019 - 2020 1&1 IONOS SE. All rights reserved.
   8  */
   9 #undef pr_fmt
  10 #define pr_fmt(fmt) KBUILD_MODNAME " L" __stringify(__LINE__) ": " fmt
  11
  12 #include <uapi/linux/limits.h>
  13 #include <linux/kobject.h>
  14 #include <linux/sysfs.h>
  15 #include <linux/stat.h>
  16 #include <linux/genhd.h>
  17 #include <linux/list.h>
  18 #include <linux/moduleparam.h>
  19 #include <linux/device.h>
  20
  21 #include "rnbd-srv.h"
  22
  23 static struct device *rnbd_dev;
  24 static struct class *rnbd_dev_class;
  25 static struct kobject *rnbd_devs_kobj;
  26
  27 static void rnbd_srv_dev_release(struct kobject *kobj)
  28 {
  29         struct rnbd_srv_dev *dev;
  30
  31         dev = container_of(kobj, struct rnbd_srv_dev, dev_kobj);
  32
  33         kfree(dev);
  34 }
  35
  36 static struct kobj_type dev_ktype = {
  37         .sysfs_ops = &kobj_sysfs_ops,
  38         .release = rnbd_srv_dev_release
  39 };
  40
  41 int rnbd_srv_create_dev_sysfs(struct rnbd_srv_dev *dev,
  42                                struct block_device *bdev,
  43                                const char *dev_name)
  44 {
  45         struct kobject *bdev_kobj;
  46         int ret;
  47
  48         ret = kobject_init_and_add(&dev->dev_kobj, &dev_ktype,
  49                                    rnbd_devs_kobj, dev_name);
  50         if (ret) {
  51                 kobject_put(&dev->dev_kobj);
  52                 return ret;
  53         }
  54
  55         dev->dev_sessions_kobj = kobject_create_and_add("sessions",
  56                                                         &dev->dev_kobj);
  57         if (!dev->dev_sessions_kobj) {
  58                 ret = -ENOMEM;
  59                 goto free_dev_kobj;
  60         }
  61
  62         bdev_kobj = &disk_to_dev(bdev->bd_disk)->kobj;
  63         ret = sysfs_create_link(&dev->dev_kobj, bdev_kobj, "block_dev");
  64         if (ret)
  65                 goto put_sess_kobj;
  66
  67         return 0;
  68
  69 put_sess_kobj:
  70         kobject_put(dev->dev_sessions_kobj);
  71 free_dev_kobj:
  72         kobject_del(&dev->dev_kobj);
  73         kobject_put(&dev->dev_kobj);
  74         return ret;
  75 }
  76
  77 void rnbd_srv_destroy_dev_sysfs(struct rnbd_srv_dev *dev)
  78 {
  79         sysfs_remove_link(&dev->dev_kobj, "block_dev");
  80         kobject_del(dev->dev_sessions_kobj);
  81         kobject_put(dev->dev_sessions_kobj);
  82         kobject_del(&dev->dev_kobj);
  83         kobject_put(&dev->dev_kobj);
  84 }
  85
  86 static ssize_t read_only_show(struct kobject *kobj, struct kobj_attribute *attr,
  87                               char *page)
  88 {
  89         struct rnbd_srv_sess_dev *sess_dev;
  90
  91         sess_dev = container_of(kobj, struct rnbd_srv_sess_dev, kobj);
  92
  93         return scnprintf(page, PAGE_SIZE, "%d\n",
  94                          !(sess_dev->open_flags & FMODE_WRITE));
  95 }
  96
  97 static struct kobj_attribute rnbd_srv_dev_session_ro_attr =
  98         __ATTR_RO(read_only);
  99
 100 static ssize_t access_mode_show(struct kobject *kobj,
 101                                 struct kobj_attribute *attr,
 102                                 char *page)
 103 {
 104         struct rnbd_srv_sess_dev *sess_dev;
 105
 106         sess_dev = container_of(kobj, struct rnbd_srv_sess_dev, kobj);
 107
 108         return scnprintf(page, PAGE_SIZE, "%s\n",
 109                          rnbd_access_mode_str(sess_dev->access_mode));
 110 }
 111
 112 static struct kobj_attribute rnbd_srv_dev_session_access_mode_attr =
 113         __ATTR_RO(access_mode);
 114
 115 static ssize_t mapping_path_show(struct kobject *kobj,
 116                                  struct kobj_attribute *attr, char *page)
 117 {
 118         struct rnbd_srv_sess_dev *sess_dev;
 119
 120         sess_dev = container_of(kobj, struct rnbd_srv_sess_dev, kobj);
 121
 122         return scnprintf(page, PAGE_SIZE, "%s\n", sess_dev->pathname);
 123 }
 124
 125 static struct kobj_attribute rnbd_srv_dev_session_mapping_path_attr =
 126         __ATTR_RO(mapping_path);
 127
 128 static ssize_t rnbd_srv_dev_session_force_close_show(struct kobject *kobj,
 129                                         struct kobj_attribute *attr, char *page)
 130 {
 131         return scnprintf(page, PAGE_SIZE, "Usage: echo 1 > %s\n",
 132                          attr->attr.name);
 133 }
 134
 135 static ssize_t rnbd_srv_dev_session_force_close_store(struct kobject *kobj,
 136                                         struct kobj_attribute *attr,
 137                                         const char *buf, size_t count)
 138 {
 139         struct rnbd_srv_sess_dev *sess_dev;
 140
 141         sess_dev = container_of(kobj, struct rnbd_srv_sess_dev, kobj);
 142
 143         if (!sysfs_streq(buf, "1")) {
 144                 rnbd_srv_err(sess_dev, "%s: invalid value: '%s'\n",
 145                               attr->attr.name, buf);
 146                 return -EINVAL;
 147         }
 148
 149         rnbd_srv_info(sess_dev, "force close requested\n");
 150
 151         /* first remove sysfs itself to avoid deadlock */
 152         sysfs_remove_file_self(&sess_dev->kobj, &attr->attr);
 153         rnbd_srv_sess_dev_force_close(sess_dev);
 154
 155         return count;
 156 }
 157
 158 static struct kobj_attribute rnbd_srv_dev_session_force_close_attr =
 159         __ATTR(force_close, 0644,
 160                rnbd_srv_dev_session_force_close_show,
 161                rnbd_srv_dev_session_force_close_store);
 162
 163 static struct attribute *rnbd_srv_default_dev_sessions_attrs[] = {
 164         &rnbd_srv_dev_session_access_mode_attr.attr,
 165         &rnbd_srv_dev_session_ro_attr.attr,
 166         &rnbd_srv_dev_session_mapping_path_attr.attr,
 167         &rnbd_srv_dev_session_force_close_attr.attr,
 168         NULL,
 169 };
 170
 171 static struct attribute_group rnbd_srv_default_dev_session_attr_group = {
 172         .attrs = rnbd_srv_default_dev_sessions_attrs,
 173 };
 174
 175 void rnbd_srv_destroy_dev_session_sysfs(struct rnbd_srv_sess_dev *sess_dev)
 176 {
 177         sysfs_remove_group(&sess_dev->kobj,
 178                            &rnbd_srv_default_dev_session_attr_group);
 179
 180         kobject_del(&sess_dev->kobj);
 181         kobject_put(&sess_dev->kobj);
 182 }
 183
 184 static void rnbd_srv_sess_dev_release(struct kobject *kobj)
 185 {
 186         struct rnbd_srv_sess_dev *sess_dev;
 187
 188         sess_dev = container_of(kobj, struct rnbd_srv_sess_dev, kobj);
 189         rnbd_destroy_sess_dev(sess_dev, sess_dev->keep_id);
 190 }
 191
 192 static struct kobj_type rnbd_srv_sess_dev_ktype = {
 193         .sysfs_ops      = &kobj_sysfs_ops,
 194         .release        = rnbd_srv_sess_dev_release,
 195 };
 196
 197 int rnbd_srv_create_dev_session_sysfs(struct rnbd_srv_sess_dev *sess_dev)
 198 {
 199         int ret;
 200
 201         ret = kobject_init_and_add(&sess_dev->kobj, &rnbd_srv_sess_dev_ktype,
 202                                    sess_dev->dev->dev_sessions_kobj, "%s",
 203                                    sess_dev->sess->sessname);
 204         if (ret) {
 205                 kobject_put(&sess_dev->kobj);
 206                 return ret;
 207         }
 208
 209         ret = sysfs_create_group(&sess_dev->kobj,
 210                                  &rnbd_srv_default_dev_session_attr_group);
 211         if (ret) {
 212                 kobject_del(&sess_dev->kobj);
 213                 kobject_put(&sess_dev->kobj);
 214         }
 215
 216         return ret;
 217 }
 218
 219 int rnbd_srv_create_sysfs_files(void)
 220 {
 221         int err;
 222
 223         rnbd_dev_class = class_create(THIS_MODULE, "rnbd-server");
 224         if (IS_ERR(rnbd_dev_class))
 225                 return PTR_ERR(rnbd_dev_class);
 226
 227         rnbd_dev = device_create(rnbd_dev_class, NULL,
 228                                   MKDEV(0, 0), NULL, "ctl");
 229         if (IS_ERR(rnbd_dev)) {
 230                 err = PTR_ERR(rnbd_dev);
 231                 goto cls_destroy;
 232         }
 233         rnbd_devs_kobj = kobject_create_and_add("devices", &rnbd_dev->kobj);
 234         if (!rnbd_devs_kobj) {
 235                 err = -ENOMEM;
 236                 goto dev_destroy;
 237         }
 238
 239         return 0;
 240
 241 dev_destroy:
 242         device_destroy(rnbd_dev_class, MKDEV(0, 0));
 243 cls_destroy:
 244         class_destroy(rnbd_dev_class);
 245
 246         return err;
 247 }
 248
 249 void rnbd_srv_destroy_sysfs_files(void)
 250 {
 251         kobject_del(rnbd_devs_kobj);
 252         kobject_put(rnbd_devs_kobj);
 253         device_destroy(rnbd_dev_class, MKDEV(0, 0));
 254         class_destroy(rnbd_dev_class);
 255 }