cfg80211: remove radar requirements check from cfg80211_can_use_iftype_chan()

We don't have to double check whether the parameters passed to
cfg80211_can_use_iftype_chan() are correct.  We should just make sure
they *are* when we call this function.

Remove the radar_detect argument check in
cfg80211_can_use_iftype_chan() to simplify the code.

Signed-off-by: Luciano Coelho <luciano.coelho@intel.com>
[keep braces around a long comment + single statement]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

3 files changed, 10 insertions, 34 deletions

diff --git a/net/wireless/ibss.c b/net/wireless/ibss.c
index 1470b90e438f..349db9ddc0d1 100644
--- a/net/wireless/ibss.c
+++ b/net/wireless/ibss.c
@@ -128,12 +128,11 @@ int __cfg80211_join_ibss(struct cfg80211_registered_device *rdev,
 #endif
         check_chan = params->chandef.chan;
         if (params->userspace_handles_dfs) {
-                /* use channel NULL to check for radar even if the current
-                 * channel is not a radar channel - it might decide to change
-                 * to DFS channel later.
+                /* Check for radar even if the current channel is not
+                 * a radar channel - it might decide to change to DFS
+                 * channel later.
                  */
                 radar_detect_width = BIT(params->chandef.width);
-                check_chan = NULL;
         }
 
         err = cfg80211_can_use_iftype_chan(rdev, wdev, wdev->iftype,
diff --git a/net/wireless/mesh.c b/net/wireless/mesh.c
index d42a3fcb2f67..5af5cc6b2c4c 100644
--- a/net/wireless/mesh.c
+++ b/net/wireless/mesh.c
@@ -236,6 +236,12 @@ int cfg80211_set_mesh_channel(struct cfg80211_registered_device *rdev,
                 if (!netif_running(wdev->netdev))
                         return -ENETDOWN;
 
+                /* cfg80211_can_use_chan() calls
+                 * cfg80211_can_use_iftype_chan() with no radar
+                 * detection, so if we're trying to use a radar
+                 * channel here, something is wrong.
+                 */
+                WARN_ON_ONCE(chandef->chan->flags & IEEE80211_CHAN_RADAR);
                 err = cfg80211_can_use_chan(rdev, wdev, chandef->chan,
                                             CHAN_MODE_SHARED);
                 if (err)
diff --git a/net/wireless/util.c b/net/wireless/util.c
index 780b4546c9c7..57b3ce7a6b92 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -1269,7 +1269,6 @@ int cfg80211_can_use_iftype_chan(struct cfg80211_registered_device *rdev,
         enum cfg80211_chan_mode chmode;
         int num_different_channels = 0;
         int total = 1;
-        bool radar_required = false;
         int i, j;
 
         ASSERT_RTNL();
@@ -1277,35 +1276,7 @@ int cfg80211_can_use_iftype_chan(struct cfg80211_registered_device *rdev,
         if (WARN_ON(hweight32(radar_detect) > 1))
                 return -EINVAL;
 
-        switch (iftype) {
-        case NL80211_IFTYPE_ADHOC:
-        case NL80211_IFTYPE_AP:
-        case NL80211_IFTYPE_AP_VLAN:
-        case NL80211_IFTYPE_MESH_POINT:
-        case NL80211_IFTYPE_P2P_GO:
-        case NL80211_IFTYPE_WDS:
-                /* if the interface could potentially choose a DFS channel,
-                 * then mark DFS as required.
-                 */
-                if (!chan) {
-                        if (chanmode != CHAN_MODE_UNDEFINED && radar_detect)
-                                radar_required = true;
-                        break;
-                }
-                radar_required = !!(chan->flags & IEEE80211_CHAN_RADAR);
-                break;
-        case NL80211_IFTYPE_P2P_CLIENT:
-        case NL80211_IFTYPE_STATION:
-        case NL80211_IFTYPE_P2P_DEVICE:
-        case NL80211_IFTYPE_MONITOR:
-                break;
-        case NUM_NL80211_IFTYPES:
-        case NL80211_IFTYPE_UNSPECIFIED:
-        default:
-                return -EINVAL;
-        }
-
-        if (radar_required && !radar_detect)
+        if (WARN_ON(iftype >= NUM_NL80211_IFTYPES))
                 return -EINVAL;
 
         /* Always allow software iftypes */