Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[linux-2.6] / 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
26 #include "dm.h"
27 #include "dm-uevent.h"
28
29 #define DM_MSG_PREFIX "uevent"
30
31 static const struct {
32         enum dm_uevent_type type;
33         enum kobject_action action;
34         char *name;
35 } _dm_uevent_type_names[] = {
36         {DM_UEVENT_PATH_FAILED, KOBJ_CHANGE, "PATH_FAILED"},
37         {DM_UEVENT_PATH_REINSTATED, KOBJ_CHANGE, "PATH_REINSTATED"},
38 };
39
40 static struct kmem_cache *_dm_event_cache;
41
42 struct dm_uevent {
43         struct mapped_device *md;
44         enum kobject_action action;
45         struct kobj_uevent_env ku_env;
46         struct list_head elist;
47         char name[DM_NAME_LEN];
48         char uuid[DM_UUID_LEN];
49 };
50
51 static void dm_uevent_free(struct dm_uevent *event)
52 {
53         kmem_cache_free(_dm_event_cache, event);
54 }
55
56 static struct dm_uevent *dm_uevent_alloc(struct mapped_device *md)
57 {
58         struct dm_uevent *event;
59
60         event = kmem_cache_zalloc(_dm_event_cache, GFP_ATOMIC);
61         if (!event)
62                 return NULL;
63
64         INIT_LIST_HEAD(&event->elist);
65         event->md = md;
66
67         return event;
68 }
69
70 static struct dm_uevent *dm_build_path_uevent(struct mapped_device *md,
71                                               struct dm_target *ti,
72                                               enum kobject_action action,
73                                               const char *dm_action,
74                                               const char *path,
75                                               unsigned nr_valid_paths)
76 {
77         struct dm_uevent *event;
78
79         event = dm_uevent_alloc(md);
80         if (!event) {
81                 DMERR("%s: dm_uevent_alloc() failed", __func__);
82                 goto err_nomem;
83         }
84
85         event->action = action;
86
87         if (add_uevent_var(&event->ku_env, "DM_TARGET=%s", ti->type->name)) {
88                 DMERR("%s: add_uevent_var() for DM_TARGET failed",
89                       __func__);
90                 goto err_add;
91         }
92
93         if (add_uevent_var(&event->ku_env, "DM_ACTION=%s", dm_action)) {
94                 DMERR("%s: add_uevent_var() for DM_ACTION failed",
95                       __func__);
96                 goto err_add;
97         }
98
99         if (add_uevent_var(&event->ku_env, "DM_SEQNUM=%u",
100                            dm_next_uevent_seq(md))) {
101                 DMERR("%s: add_uevent_var() for DM_SEQNUM failed",
102                       __func__);
103                 goto err_add;
104         }
105
106         if (add_uevent_var(&event->ku_env, "DM_PATH=%s", path)) {
107                 DMERR("%s: add_uevent_var() for DM_PATH failed", __func__);
108                 goto err_add;
109         }
110
111         if (add_uevent_var(&event->ku_env, "DM_NR_VALID_PATHS=%d",
112                            nr_valid_paths)) {
113                 DMERR("%s: add_uevent_var() for DM_NR_VALID_PATHS failed",
114                       __func__);
115                 goto err_add;
116         }
117
118         return event;
119
120 err_add:
121         dm_uevent_free(event);
122 err_nomem:
123         return ERR_PTR(-ENOMEM);
124 }
125
126 /**
127  * dm_send_uevents - send uevents for given list
128  *
129  * @events:     list of events to send
130  * @kobj:       kobject generating event
131  *
132  */
133 void dm_send_uevents(struct list_head *events, struct kobject *kobj)
134 {
135         int r;
136         struct dm_uevent *event, *next;
137
138         list_for_each_entry_safe(event, next, events, elist) {
139                 list_del_init(&event->elist);
140
141                 /*
142                  * Need to call dm_copy_name_and_uuid from here for now.
143                  * Context of previous var adds and locking used for
144                  * hash_cell not compatable.
145                  */
146                 if (dm_copy_name_and_uuid(event->md, event->name,
147                                           event->uuid)) {
148                         DMERR("%s: dm_copy_name_and_uuid() failed",
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                 goto out;
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                 goto out;
200
201         dm_uevent_add(md, &event->elist);
202
203 out:
204         dm_put(md);
205 }
206 EXPORT_SYMBOL_GPL(dm_path_uevent);
207
208 int dm_uevent_init(void)
209 {
210         _dm_event_cache = KMEM_CACHE(dm_uevent, 0);
211         if (!_dm_event_cache)
212                 return -ENOMEM;
213
214         DMINFO("version 1.0.3");
215
216         return 0;
217 }
218
219 void dm_uevent_exit(void)
220 {
221         kmem_cache_destroy(_dm_event_cache);
222 }