cfg80211: clarify set_channel APIs

Now that we've removed all uses of the set_channel
API except for the monitor channel and in libertas,
clarify this. Split the libertas mesh use into a
new libertas_set_mesh_channel() operation, just to
keep backward compatibility, and rename the normal
set_channel() to set_monitor_channel().

Also describe the desired set_monitor_channel()
semantics more clearly.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

7 files changed, 42 insertions, 75 deletions

diff --git a/net/wireless/chan.c b/net/wireless/chan.c
index 20b87d8..c1999e4 100644
--- a/net/wireless/chan.c
+++ b/net/wireless/chan.c
@@ -78,50 +78,17 @@ bool cfg80211_can_beacon_sec_chan(struct wiphy *wiphy,
 }
 EXPORT_SYMBOL(cfg80211_can_beacon_sec_chan);
 
-int cfg80211_set_freq(struct cfg80211_registered_device *rdev,
-		      struct wireless_dev *wdev, int freq,
-		      enum nl80211_channel_type channel_type)
+int cfg80211_set_monitor_channel(struct cfg80211_registered_device *rdev,
+				 int freq, enum nl80211_channel_type chantype)
 {
 	struct ieee80211_channel *chan;
-	int result;
 
-	if (wdev && wdev->iftype == NL80211_IFTYPE_MONITOR)
-		wdev = NULL;
-
-	if (wdev) {
-		ASSERT_WDEV_LOCK(wdev);
-
-		if (!netif_running(wdev->netdev))
-			return -ENETDOWN;
-	}
-
-	if (!rdev->ops->set_channel)
+	if (!rdev->ops->set_monitor_channel)
 		return -EOPNOTSUPP;
 
-	chan = rdev_freq_to_chan(rdev, freq, channel_type);
+	chan = rdev_freq_to_chan(rdev, freq, chantype);
 	if (!chan)
 		return -EINVAL;
 
-	/* Both channels should be able to initiate communication */
-	if (wdev && (wdev->iftype == NL80211_IFTYPE_ADHOC ||
-		     wdev->iftype == NL80211_IFTYPE_AP ||
-		     wdev->iftype == NL80211_IFTYPE_AP_VLAN ||
-		     wdev->iftype == NL80211_IFTYPE_MESH_POINT ||
-		     wdev->iftype == NL80211_IFTYPE_P2P_GO) &&
-	    !cfg80211_can_beacon_sec_chan(&rdev->wiphy, chan, channel_type)) {
-		printk(KERN_DEBUG
-		       "cfg80211: Secondary channel not allowed to beacon\n");
-		return -EINVAL;
-	}
-
-	result = rdev->ops->set_channel(&rdev->wiphy,
-					wdev ? wdev->netdev : NULL,
-					chan, channel_type);
-	if (result)
-		return result;
-
-	if (wdev)
-		wdev->channel = chan;
-
-	return 0;
+	return rdev->ops->set_monitor_channel(&rdev->wiphy, chan, chantype);
 }
diff --git a/net/wireless/core.h b/net/wireless/core.h
index 1d3d241..9348a47 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -444,9 +444,8 @@ cfg80211_can_add_interface(struct cfg80211_registered_device *rdev,
 struct ieee80211_channel *
 rdev_freq_to_chan(struct cfg80211_registered_device *rdev,
 		  int freq, enum nl80211_channel_type channel_type);
-int cfg80211_set_freq(struct cfg80211_registered_device *rdev,
-		      struct wireless_dev *wdev, int freq,
-		      enum nl80211_channel_type channel_type);
+int cfg80211_set_monitor_channel(struct cfg80211_registered_device *rdev,
+				 int freq, enum nl80211_channel_type chantype);
 
 int ieee80211_get_ratemask(struct ieee80211_supported_band *sband,
 			   const u8 *rates, unsigned int n_rates,
diff --git a/net/wireless/mesh.c b/net/wireless/mesh.c
index 2e3b700..b44c736 100644
--- a/net/wireless/mesh.c
+++ b/net/wireless/mesh.c
@@ -179,6 +179,13 @@ int cfg80211_set_mesh_freq(struct cfg80211_registered_device *rdev,
 {
 	struct ieee80211_channel *channel;
 
+	channel = rdev_freq_to_chan(rdev, freq, channel_type);
+	if (!channel || !cfg80211_can_beacon_sec_chan(&rdev->wiphy,
+						      channel,
+						      channel_type)) {
+		return -EINVAL;
+	}
+
 	/*
 	 * Workaround for libertas (only!), it puts the interface
 	 * into mesh mode but doesn't implement join_mesh. Instead,
@@ -186,27 +193,20 @@ int cfg80211_set_mesh_freq(struct cfg80211_registered_device *rdev,
 	 * you set the channel. Note that the libertas mesh isn't
 	 * compatible with 802.11 mesh.
 	 */
-	if (!rdev->ops->join_mesh) {
-		int err;
+	if (rdev->ops->libertas_set_mesh_channel) {
+		if (channel_type != NL80211_CHAN_NO_HT)
+			return -EINVAL;
 
 		if (!netif_running(wdev->netdev))
 			return -ENETDOWN;
-		wdev_lock(wdev);
-		err = cfg80211_set_freq(rdev, wdev, freq, channel_type);
-		wdev_unlock(wdev);
-
-		return err;
+		return rdev->ops->libertas_set_mesh_channel(&rdev->wiphy,
+							    wdev->netdev,
+							    channel);
 	}
 
 	if (wdev->mesh_id_len)
 		return -EBUSY;
 
-	channel = rdev_freq_to_chan(rdev, freq, channel_type);
-	if (!channel || !cfg80211_can_beacon_sec_chan(&rdev->wiphy,
-						      channel,
-						      channel_type)) {
-		return -EINVAL;
-	}
 	wdev->preset_chan = channel;
 	wdev->preset_chantype = channel_type;
 	return 0;
diff --git a/net/wireless/mlme.c b/net/wireless/mlme.c
index eb90988..da4406f 100644
--- a/net/wireless/mlme.c
+++ b/net/wireless/mlme.c
@@ -947,8 +947,6 @@ void cfg80211_ch_switch_notify(struct net_device *dev, int freq,
 	if (WARN_ON(!chan))
 		goto out;
 
-	wdev->channel = chan;
-
 	nl80211_ch_switch_notify(rdev, dev, freq, type, GFP_KERNEL);
 out:
 	wdev_unlock(wdev);
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index b22f1f8..5e29bd3 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -921,7 +921,7 @@ static int nl80211_send_wiphy(struct sk_buff *msg, u32 pid, u32 seq, int flags,
 		if (nla_put_u32(msg, i, NL80211_CMD_SET_WIPHY_NETNS))
 			goto nla_put_failure;
 	}
-	if (dev->ops->set_channel || dev->ops->start_ap ||
+	if (dev->ops->set_monitor_channel || dev->ops->start_ap ||
 	    dev->ops->join_mesh) {
 		i++;
 		if (nla_put_u32(msg, i, NL80211_CMD_SET_CHANNEL))
@@ -1178,8 +1178,8 @@ static bool nl80211_can_set_dev_channel(struct wireless_dev *wdev)
 	 * the channel in the start-ap or join-mesh commands instead.
 	 *
 	 * Monitors are special as they are normally slaved to
-	 * whatever else is going on, so they behave as though
-	 * you tried setting the wiphy channel itself.
+	 * whatever else is going on, so they have their own special
+	 * operation to set the monitor channel if possible.
 	 */
 	return !wdev ||
 		wdev->iftype == NL80211_IFTYPE_AP ||
@@ -1217,6 +1217,10 @@ static int __nl80211_set_channel(struct cfg80211_registered_device *rdev,
 	enum nl80211_channel_type channel_type = NL80211_CHAN_NO_HT;
 	u32 freq;
 	int result;
+	enum nl80211_iftype iftype = NL80211_IFTYPE_MONITOR;
+
+	if (wdev)
+		iftype = wdev->iftype;
 
 	if (!info->attrs[NL80211_ATTR_WIPHY_FREQ])
 		return -EINVAL;
@@ -1231,7 +1235,7 @@ static int __nl80211_set_channel(struct cfg80211_registered_device *rdev,
 	freq = nla_get_u32(info->attrs[NL80211_ATTR_WIPHY_FREQ]);
 
 	mutex_lock(&rdev->devlist_mtx);
-	if (wdev) switch (wdev->iftype) {
+	switch (iftype) {
 	case NL80211_IFTYPE_AP:
 	case NL80211_IFTYPE_P2P_GO:
 		if (wdev->beacon_interval) {
@@ -1252,12 +1256,11 @@ static int __nl80211_set_channel(struct cfg80211_registered_device *rdev,
 	case NL80211_IFTYPE_MESH_POINT:
 		result = cfg80211_set_mesh_freq(rdev, wdev, freq, channel_type);
 		break;
+	case NL80211_IFTYPE_MONITOR:
+		result = cfg80211_set_monitor_channel(rdev, freq, channel_type);
+		break;
 	default:
-		wdev_lock(wdev);
-		result = cfg80211_set_freq(rdev, wdev, freq, channel_type);
-		wdev_unlock(wdev);
-	} else {
-		result = cfg80211_set_freq(rdev, NULL, freq, channel_type);
+		result = -EINVAL;
 	}
 	mutex_unlock(&rdev->devlist_mtx);
 
diff --git a/net/wireless/wext-compat.c b/net/wireless/wext-compat.c
index faeb035..bc87983 100644
--- a/net/wireless/wext-compat.c
+++ b/net/wireless/wext-compat.c
@@ -802,9 +802,7 @@ static int cfg80211_wext_siwfreq(struct net_device *dev,
 		if (freq == 0)
 			return -EINVAL;
 		mutex_lock(&rdev->devlist_mtx);
-		wdev_lock(wdev);
-		err = cfg80211_set_freq(rdev, wdev, freq, NL80211_CHAN_NO_HT);
-		wdev_unlock(wdev);
+		err = cfg80211_set_monitor_channel(rdev, freq, NL80211_CHAN_NO_HT);
 		mutex_unlock(&rdev->devlist_mtx);
 		return err;
 	case NL80211_IFTYPE_MESH_POINT:
@@ -848,11 +846,7 @@ static int cfg80211_wext_giwfreq(struct net_device *dev,
 		freq->e = 6;
 		return 0;
 	default:
-		if (!wdev->channel)
-			return -EINVAL;
-		freq->m = wdev->channel->center_freq;
-		freq->e = 6;
-		return 0;
+		return -EINVAL;
 	}
 }
 
diff --git a/net/wireless/wext-sme.c b/net/wireless/wext-sme.c
index 7decbd3..1f773f6 100644
--- a/net/wireless/wext-sme.c
+++ b/net/wireless/wext-sme.c
@@ -111,9 +111,15 @@ int cfg80211_mgd_wext_siwfreq(struct net_device *dev,
 
 	wdev->wext.connect.channel = chan;
 
-	/* SSID is not set, we just want to switch channel */
+	/*
+	 * SSID is not set, we just want to switch monitor channel,
+	 * this is really just backward compatibility, if the SSID
+	 * is set then we use the channel to select the BSS to use
+	 * to connect to instead. If we were connected on another
+	 * channel we disconnected above and reconnect below.
+	 */
 	if (chan && !wdev->wext.connect.ssid_len) {
-		err = cfg80211_set_freq(rdev, wdev, freq, NL80211_CHAN_NO_HT);
+		err = cfg80211_set_monitor_channel(rdev, freq, NL80211_CHAN_NO_HT);
 		goto out;
 	}