drivers/md/dm-uevent.c

   1 /*
   2  * Device Mapper Uevent Support (dm-uevent)
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License as published by the
   6  * Free Software Foundation; either version 2 of the License, or (at your
   7  * option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  17  *
  18  * Copyright IBM Corporation, 2007
  19  *      Author: Mike Anderson <andmike@linux.vnet.ibm.com>
  20  */
  21 #include <linux/list.h>
  22 #include <linux/slab.h>
  23 #include <linux/kobject.h>
  24 #include <linux/dm-ioctl.h>
  25 #include <linux/export.h>
  26
  27 #include "dm.h"
  28 #include "dm-uevent.h"
  29
  30 #define DM_MSG_PREFIX "uevent"
  31
  32 static const struct {
  33         enum dm_uevent_type type;
  34         enum kobject_action action;
  35         char *name;
  36 } _dm_uevent_type_names[] = {
  37         {DM_UEVENT_PATH_FAILED, KOBJ_CHANGE, "PATH_FAILED"},
  38         {DM_UEVENT_PATH_REINSTATED, KOBJ_CHANGE, "PATH_REINSTATED"},
  39 };
  40
  41 static struct kmem_cache *_dm_event_cache;
  42
  43 struct dm_uevent {
  44         struct mapped_device *md;
  45         enum kobject_action action;
  46         struct kobj_uevent_env ku_env;
  47         struct list_head elist;
  48         char name[DM_NAME_LEN];
  49         char uuid[DM_UUID_LEN];
  50 };
  51
  52 static void dm_uevent_free(struct dm_uevent *event)
  53 {
  54         kmem_cache_free(_dm_event_cache, event);
  55 }
  56
  57 static struct dm_uevent *dm_uevent_alloc(struct mapped_device *md)
  58 {
  59         struct dm_uevent *event;
  60
  61         event = kmem_cache_zalloc(_dm_event_cache, GFP_ATOMIC);
  62         if (!event)
  63                 return NULL;
  64
  65         INIT_LIST_HEAD(&event->elist);
  66         event->md = md;
  67
  68         return event;
  69 }
  70
  71 static struct dm_uevent *dm_build_path_uevent(struct mapped_device *md,
  72                                               struct dm_target *ti,
  73                                               enum kobject_action action,
  74                                               const char *dm_action,
  75                                               const char *path,
  76                                               unsigned nr_valid_paths)
  77 {
  78         struct dm_uevent *event;
  79
  80         event = dm_uevent_alloc(md);
  81         if (!event) {
  82                 DMERR("%s: dm_uevent_alloc() failed", __func__);
  83                 goto err_nomem;
  84         }
  85
  86         event->action = action;
  87
  88         if (add_uevent_var(&event->ku_env, "DM_TARGET=%s", ti->type->name)) {
  89                 DMERR("%s: add_uevent_var() for DM_TARGET failed",
  90                       __func__);
  91                 goto err_add;
  92         }
  93
  94         if (add_uevent_var(&event->ku_env, "DM_ACTION=%s", dm_action)) {
  95                 DMERR("%s: add_uevent_var() for DM_ACTION failed",
  96                       __func__);
  97                 goto err_add;
  98         }
  99
 100         if (add_uevent_var(&event->ku_env, "DM_SEQNUM=%u",
 101                            dm_next_uevent_seq(md))) {
 102                 DMERR("%s: add_uevent_var() for DM_SEQNUM failed",
 103                       __func__);
 104                 goto err_add;
 105         }
 106
 107         if (add_uevent_var(&event->ku_env, "DM_PATH=%s", path)) {
 108                 DMERR("%s: add_uevent_var() for DM_PATH failed", __func__);
 109                 goto err_add;
 110         }
 111
 112         if (add_uevent_var(&event->ku_env, "DM_NR_VALID_PATHS=%d",
 113                            nr_valid_paths)) {
 114                 DMERR("%s: add_uevent_var() for DM_NR_VALID_PATHS failed",
 115                       __func__);
 116                 goto err_add;
 117         }
 118
 119         return event;
 120
 121 err_add:
 122         dm_uevent_free(event);
 123 err_nomem:
 124         return ERR_PTR(-ENOMEM);
 125 }
 126
 127 /**
 128  * dm_send_uevents - send uevents for given list
 129  *
 130  * @events:     list of events to send
 131  * @kobj:       kobject generating event
 132  *
 133  */
 134 void dm_send_uevents(struct list_head *events, struct kobject *kobj)
 135 {
 136         int r;
 137         struct dm_uevent *event, *next;
 138
 139         list_for_each_entry_safe(event, next, events, elist) {
 140                 list_del_init(&event->elist);
 141
 142                 /*
 143                  * When a device is being removed this copy fails and we
 144                  * discard these unsent events.
 145                  */
 146                 if (dm_copy_name_and_uuid(event->md, event->name,
 147                                           event->uuid)) {
 148                         DMINFO("%s: skipping sending uevent for lost device",
 149                                __func__);
 150                         goto uevent_free;
 151                 }
 152
 153                 if (add_uevent_var(&event->ku_env, "DM_NAME=%s", event->name)) {
 154                         DMERR("%s: add_uevent_var() for DM_NAME failed",
 155                               __func__);
 156                         goto uevent_free;
 157                 }
 158
 159                 if (add_uevent_var(&event->ku_env, "DM_UUID=%s", event->uuid)) {
 160                         DMERR("%s: add_uevent_var() for DM_UUID failed",
 161                               __func__);
 162                         goto uevent_free;
 163                 }
 164
 165                 r = kobject_uevent_env(kobj, event->action, event->ku_env.envp);
 166                 if (r)
 167                         DMERR("%s: kobject_uevent_env failed", __func__);
 168 uevent_free:
 169                 dm_uevent_free(event);
 170         }
 171 }
 172 EXPORT_SYMBOL_GPL(dm_send_uevents);
 173
 174 /**
 175  * dm_path_uevent - called to create a new path event and queue it
 176  *
 177  * @event_type: path event type enum
 178  * @ti:                 pointer to a dm_target
 179  * @path:               string containing pathname
 180  * @nr_valid_paths:     number of valid paths remaining
 181  *
 182  */
 183 void dm_path_uevent(enum dm_uevent_type event_type, struct dm_target *ti,
 184                    const char *path, unsigned nr_valid_paths)
 185 {
 186         struct mapped_device *md = dm_table_get_md(ti->table);
 187         struct dm_uevent *event;
 188
 189         if (event_type >= ARRAY_SIZE(_dm_uevent_type_names)) {
 190                 DMERR("%s: Invalid event_type %d", __func__, event_type);
 191                 return;
 192         }
 193
 194         event = dm_build_path_uevent(md, ti,
 195                                      _dm_uevent_type_names[event_type].action,
 196                                      _dm_uevent_type_names[event_type].name,
 197                                      path, nr_valid_paths);
 198         if (IS_ERR(event))
 199                 return;
 200
 201         dm_uevent_add(md, &event->elist);
 202 }
 203 EXPORT_SYMBOL_GPL(dm_path_uevent);
 204
 205 int dm_uevent_init(void)
 206 {
 207         _dm_event_cache = KMEM_CACHE(dm_uevent, 0);
 208         if (!_dm_event_cache)
 209                 return -ENOMEM;
 210
 211         DMINFO("version 1.0.3");
 212
 213         return 0;
 214 }
 215
 216 void dm_uevent_exit(void)
 217 {
 218         kmem_cache_destroy(_dm_event_cache);
 219 }