mac80211: schedule the actual switch of the station before CSA count 0

commit ff1e417c7c239b7abfe70aa90460a77eaafc7f83 upstream.

Due to the time it takes to process the beacon that started the CSA
process, we may be late for the switch if we try to reach exactly
beacon 0.  To avoid that, use count - 1 when calculating the switch time.

Reported-by: Jouni Malinen <j@w1.fi>
Signed-off-by: Luciano Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index d870aa09ae4fc4cb4489fa3403e21ce3195e1719..c9535a976b564b10e2e4619ce0227b65ed63926d 100644 (file)
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -1086,7 +1086,8 @@ ieee80211_sta_process_chanswitch(struct ieee80211_sub_if_data *sdata,
                ieee80211_queue_work(&local->hw, &ifmgd->chswitch_work);
        else
                mod_timer(&ifmgd->chswitch_timer,
-                         TU_TO_EXP_TIME(csa_ie.count * cbss->beacon_interval));
+                         TU_TO_EXP_TIME((csa_ie.count - 1) *
+                                        cbss->beacon_interval));
 }
 
 static u32 ieee80211_handle_pwr_constr(struct ieee80211_sub_if_data *sdata,