linux/drivers/md/dm-uevent.c
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   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
  32static 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
  41static struct kmem_cache *_dm_event_cache;
  42
  43struct 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
  52static void dm_uevent_free(struct dm_uevent *event)
  53{
  54        kmem_cache_free(_dm_event_cache, event);
  55}
  56
  57static 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
  71static 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
 121err_add:
 122        dm_uevent_free(event);
 123err_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 */
 134void 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__);
 168uevent_free:
 169                dm_uevent_free(event);
 170        }
 171}
 172EXPORT_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 */
 183void 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}
 203EXPORT_SYMBOL_GPL(dm_path_uevent);
 204
 205int 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
 216void dm_uevent_exit(void)
 217{
 218        kmem_cache_destroy(_dm_event_cache);
 219}
 220
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