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 20b87d895722..c1999e45a07c 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 1d3d24126946..9348a47562a4 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 2e3b700eba32..b44c736bf9cf 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 eb90988bbd36..da4406f11929 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 b22f1f876881..5e29bd38e7df 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 faeb03548aa4..bc879833b21f 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 7decbd357d51..1f773f668d1a 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;
         }