cfg80211: consider existing DFS interfaces

It was possible to break interface combinations in
the following way:

 combo 1: iftype = AP, num_ifaces = 2, num_chans = 2,
 combo 2: iftype = AP, num_ifaces = 1, num_chans = 1, radar = HT20

With the above interface combinations it was
possible to:

 step 1. start AP on DFS channel by matching combo 2
 step 2. start AP on non-DFS channel by matching combo 1

This was possible beacuse (step 2) did not consider
if other interfaces require radar detection.

The patch changes how cfg80211 tracks channels -
instead of channel itself now a complete chandef
is stored.

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

1 files changed, 2 insertions, 0 deletions

diff --git a/net/wireless/ibss.c b/net/wireless/ibss.c
index e37e39c29dfb..1470b90e438f 100644
--- a/net/wireless/ibss.c
+++ b/net/wireless/ibss.c
@@ -122,6 +122,7 @@ int __cfg80211_join_ibss(struct cfg80211_registered_device *rdev,
 
         wdev->ibss_fixed = params->channel_fixed;
         wdev->ibss_dfs_possible = params->userspace_handles_dfs;
+        wdev->chandef = params->chandef;
 #ifdef CONFIG_CFG80211_WEXT
         wdev->wext.ibss.chandef = params->chandef;
 #endif
@@ -205,6 +206,7 @@ static void __cfg80211_clear_ibss(struct net_device *dev, bool nowext)
 
         wdev->current_bss = NULL;
         wdev->ssid_len = 0;
+        memset(&wdev->chandef, 0, sizeof(wdev->chandef));
 #ifdef CONFIG_CFG80211_WEXT
         if (!nowext)
                 wdev->wext.ibss.ssid_len = 0;