cfg80211: track monitor channel

Make it even more obvious we support single
monitor channel. This will allow us to remove
.get_channel.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/chan.c

@@ -82,6 +82,7 @@ int cfg80211_set_monitor_channel(struct cfg80211_registered_device *rdev,
 				 int freq, enum nl80211_channel_type chantype)
 {
 	struct ieee80211_channel *chan;
+	int err;
 
 	if (!rdev->ops->set_monitor_channel)
 		return -EOPNOTSUPP;
@@ -92,7 +93,13 @@ int cfg80211_set_monitor_channel(struct cfg80211_registered_device *rdev,
 	if (!chan)
 		return -EINVAL;
 
-	return rdev->ops->set_monitor_channel(&rdev->wiphy, chan, chantype);
+	err = rdev->ops->set_monitor_channel(&rdev->wiphy, chan, chantype);
+	if (!err) {
+		rdev->monitor_channel = chan;
+		rdev->monitor_channel_type = chantype;
+	}
+
+	return err;
 }
 
 void

net/wireless/core.c

@@ -730,9 +730,15 @@ void cfg80211_update_iface_num(struct cfg80211_registered_device *rdev,
 		rdev->num_running_monitor_ifaces += num;
 
 	has_monitors_only_new = cfg80211_has_monitors_only(rdev);
-	if (has_monitors_only_new != has_monitors_only_old)
+	if (has_monitors_only_new != has_monitors_only_old) {
 		rdev->ops->set_monitor_enabled(&rdev->wiphy,
 					       has_monitors_only_new);
+
+		if (!has_monitors_only_new) {
+			rdev->monitor_channel = NULL;
+			rdev->monitor_channel_type = NL80211_CHAN_NO_HT;
+		}
+	}
 }
 
 static int cfg80211_netdev_notifier_call(struct notifier_block *nb,

net/wireless/core.h

@@ -59,6 +59,9 @@ struct cfg80211_registered_device {
 	int num_running_ifaces;
 	int num_running_monitor_ifaces;
 
+	struct ieee80211_channel *monitor_channel;
+	enum nl80211_channel_type monitor_channel_type;
+
 	/* BSSes/scanning */
 	spinlock_t bss_lock;
 	struct list_head bss_list;