[PATCH 3.16.y-ckt 159/254] mac80211: schedule the actual switch of the station before CSA count 0

[Luis Henriques]

3.16.7-ckt2 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Luciano Coelho <luciano.coelho at intel.com>

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 at w1.fi>
Signed-off-by: Luciano Coelho <luciano.coelho at intel.com>
Signed-off-by: Johannes Berg <johannes.berg at intel.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 net/mac80211/mlme.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index a374bcc32706..a59a78b6923d 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -1136,7 +1136,8 @@ 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,
-- 
2.1.0