[IEEE80211]: Fix softmac lockdep reports.
[linux-2.6] / net / ieee80211 / softmac / ieee80211softmac_scan.c
1 /*
2  * Scanning routines.
3  *
4  * These are not exported because they're assigned to the function pointers.
5  *
6  * Copyright (c) 2005, 2006 Johannes Berg <johannes@sipsolutions.net>
7  *                          Joseph Jezak <josejx@gentoo.org>
8  *                          Larry Finger <Larry.Finger@lwfinger.net>
9  *                          Danny van Dyk <kugelfang@gentoo.org>
10  *                          Michael Buesch <mbuesch@freenet.de>
11  *
12  * This program is free software; you can redistribute it and/or modify it
13  * under the terms of version 2 of the GNU General Public License as
14  * published by the Free Software Foundation.
15  *
16  * This program is distributed in the hope that it will be useful, but WITHOUT
17  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
18  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
19  * more details.
20  *
21  * You should have received a copy of the GNU General Public License
22  * along with this program; if not, write to the Free Software
23  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
24  *
25  * The full GNU General Public License is included in this distribution in the
26  * file called COPYING.
27  */
28
29 #include <linux/completion.h>
30 #include "ieee80211softmac_priv.h"
31
32 /* internal, use to trigger scanning if needed.
33  * Returns -EBUSY if already scanning,
34  * result of start_scan otherwise */
35 int
36 ieee80211softmac_start_scan(struct ieee80211softmac_device *sm)
37 {
38         unsigned long flags;
39         int ret;
40
41         spin_lock_irqsave(&sm->lock, flags);
42         if (sm->scanning)
43         {
44                 spin_unlock_irqrestore(&sm->lock, flags);
45                 return -EINPROGRESS;
46         }
47         sm->scanning = 1;
48         spin_unlock_irqrestore(&sm->lock, flags);
49
50         ret = sm->start_scan(sm->dev);
51         if (ret) {
52                 spin_lock_irqsave(&sm->lock, flags);
53                 sm->scanning = 0;
54                 spin_unlock_irqrestore(&sm->lock, flags);
55         }
56         return ret;
57 }
58
59 void
60 ieee80211softmac_stop_scan(struct ieee80211softmac_device *sm)
61 {
62         unsigned long flags;
63
64         spin_lock_irqsave(&sm->lock, flags);
65
66         if (!sm->scanning) {
67                 spin_unlock_irqrestore(&sm->lock, flags);
68                 return;
69         }
70
71         spin_unlock_irqrestore(&sm->lock, flags);
72         sm->stop_scan(sm->dev);
73 }
74
75 void
76 ieee80211softmac_wait_for_scan(struct ieee80211softmac_device *sm)
77 {
78         unsigned long flags;
79
80         spin_lock_irqsave(&sm->lock, flags);
81
82         if (!sm->scanning) {
83                 spin_unlock_irqrestore(&sm->lock, flags);
84                 return;
85         }
86
87         spin_unlock_irqrestore(&sm->lock, flags);
88         sm->wait_for_scan(sm->dev);
89 }
90
91
92 /* internal scanning implementation follows */
93 void ieee80211softmac_scan(struct work_struct *work)
94 {
95         int invalid_channel;
96         u8 current_channel_idx;
97         struct ieee80211softmac_scaninfo *si =
98                 container_of(work, struct ieee80211softmac_scaninfo,
99                              softmac_scan.work);
100         struct ieee80211softmac_device *sm = si->mac;
101         unsigned long flags;
102
103         while (!(si->stop) && (si->current_channel_idx < si->number_channels)) {
104                 current_channel_idx = si->current_channel_idx;
105                 si->current_channel_idx++; /* go to the next channel */
106
107                 invalid_channel = (si->skip_flags & si->channels[current_channel_idx].flags);
108
109                 if (!invalid_channel) {
110                         sm->set_channel(sm->dev, si->channels[current_channel_idx].channel);
111                         // FIXME make this user configurable (active/passive)
112                         if(ieee80211softmac_send_mgt_frame(sm, NULL, IEEE80211_STYPE_PROBE_REQ, 0))
113                                 printkl(KERN_DEBUG PFX "Sending Probe Request Failed\n");
114
115                         /* also send directed management frame for the network we're looking for */
116                         // TODO: is this if correct, or should we do this only if scanning from assoc request?
117                         if (sm->associnfo.req_essid.len)
118                                 ieee80211softmac_send_mgt_frame(sm, &sm->associnfo.req_essid, IEEE80211_STYPE_PROBE_REQ, 0);
119
120                         spin_lock_irqsave(&sm->lock, flags);
121                         if (unlikely(!sm->running)) {
122                                 /* Prevent reschedule on workqueue flush */
123                                 spin_unlock_irqrestore(&sm->lock, flags);
124                                 break;
125                         }
126                         queue_delayed_work(sm->wq, &si->softmac_scan, IEEE80211SOFTMAC_PROBE_DELAY);
127                         spin_unlock_irqrestore(&sm->lock, flags);
128                         return;
129                 } else {
130                         dprintk(PFX "Not probing Channel %d (not allowed here)\n", si->channels[current_channel_idx].channel);
131                 }
132         }
133
134         spin_lock_irqsave(&sm->lock, flags);
135         cancel_delayed_work(&si->softmac_scan);
136         si->started = 0;
137         spin_unlock_irqrestore(&sm->lock, flags);
138
139         dprintk(PFX "Scanning finished: scanned %d channels starting with channel %d\n",
140                      sm->scaninfo->number_channels, sm->scaninfo->channels[0].channel);
141         ieee80211softmac_scan_finished(sm);
142         complete_all(&sm->scaninfo->finished);
143 }
144
145 static inline struct ieee80211softmac_scaninfo *allocate_scaninfo(struct ieee80211softmac_device *mac)
146 {
147         /* ugh. can we call this without having the spinlock held? */
148         struct ieee80211softmac_scaninfo *info = kmalloc(sizeof(struct ieee80211softmac_scaninfo), GFP_ATOMIC);
149         if (unlikely(!info))
150                 return NULL;
151         INIT_DELAYED_WORK(&info->softmac_scan, ieee80211softmac_scan);
152         info->mac = mac;
153         init_completion(&info->finished);
154         return info;
155 }
156
157 int ieee80211softmac_start_scan_implementation(struct net_device *dev)
158 {
159         struct ieee80211softmac_device *sm = ieee80211_priv(dev);
160         unsigned long flags;
161
162         if (!(dev->flags & IFF_UP))
163                 return -ENODEV;
164
165         assert(ieee80211softmac_scan_handlers_check_self(sm));
166         if (!ieee80211softmac_scan_handlers_check_self(sm))
167                 return -EINVAL;
168
169         spin_lock_irqsave(&sm->lock, flags);
170         /* it looks like we need to hold the lock here
171          * to make sure we don't allocate two of these... */
172         if (unlikely(!sm->scaninfo))
173                 sm->scaninfo = allocate_scaninfo(sm);
174         if (unlikely(!sm->scaninfo)) {
175                 spin_unlock_irqrestore(&sm->lock, flags);
176                 return -ENOMEM;
177         }
178
179         sm->scaninfo->skip_flags = IEEE80211_CH_INVALID;
180         if (0 /* not scanning in IEEE802.11b */)//TODO
181                 sm->scaninfo->skip_flags |= IEEE80211_CH_B_ONLY;
182         if (0 /* IEEE802.11a */) {//TODO
183                 sm->scaninfo->channels = sm->ieee->geo.a;
184                 sm->scaninfo->number_channels = sm->ieee->geo.a_channels;
185         } else {
186                 sm->scaninfo->channels = sm->ieee->geo.bg;
187                 sm->scaninfo->number_channels = sm->ieee->geo.bg_channels;
188         }
189         sm->scaninfo->current_channel_idx = 0;
190         sm->scaninfo->started = 1;
191         sm->scaninfo->stop = 0;
192         INIT_COMPLETION(sm->scaninfo->finished);
193         queue_delayed_work(sm->wq, &sm->scaninfo->softmac_scan, 0);
194         spin_unlock_irqrestore(&sm->lock, flags);
195         return 0;
196 }
197
198 void ieee80211softmac_stop_scan_implementation(struct net_device *dev)
199 {
200         struct ieee80211softmac_device *sm = ieee80211_priv(dev);
201         unsigned long flags;
202
203         assert(ieee80211softmac_scan_handlers_check_self(sm));
204         if (!ieee80211softmac_scan_handlers_check_self(sm))
205                 return;
206
207         spin_lock_irqsave(&sm->lock, flags);
208         assert(sm->scaninfo != NULL);
209         if (sm->scaninfo) {
210                 if (sm->scaninfo->started)
211                         sm->scaninfo->stop = 1;
212                 else
213                         complete_all(&sm->scaninfo->finished);
214         }
215         spin_unlock_irqrestore(&sm->lock, flags);
216 }
217
218 void ieee80211softmac_wait_for_scan_implementation(struct net_device *dev)
219 {
220         struct ieee80211softmac_device *sm = ieee80211_priv(dev);
221         unsigned long flags;
222
223         assert(ieee80211softmac_scan_handlers_check_self(sm));
224         if (!ieee80211softmac_scan_handlers_check_self(sm))
225                 return;
226
227         spin_lock_irqsave(&sm->lock, flags);
228         if (!sm->scaninfo->started) {
229                 spin_unlock_irqrestore(&sm->lock, flags);
230                 return;
231         }
232         spin_unlock_irqrestore(&sm->lock, flags);
233         wait_for_completion(&sm->scaninfo->finished);
234 }
235
236 /* this is what drivers (that do scanning) call when they're done */
237 void ieee80211softmac_scan_finished(struct ieee80211softmac_device *sm)
238 {
239         unsigned long flags;
240
241         spin_lock_irqsave(&sm->lock, flags);
242         sm->scanning = 0;
243         spin_unlock_irqrestore(&sm->lock, flags);
244
245         if (sm->associnfo.bssvalid) {
246                 struct ieee80211softmac_network *net;
247
248                 net = ieee80211softmac_get_network_by_bssid(sm, sm->associnfo.bssid);
249                 if (net)
250                         sm->set_channel(sm->dev, net->channel);
251         }
252         ieee80211softmac_call_events(sm, IEEE80211SOFTMAC_EVENT_SCAN_FINISHED, NULL);
253 }
254 EXPORT_SYMBOL_GPL(ieee80211softmac_scan_finished);