mac80211: fix queues stuck issue with HT bandwidth change

No upstream commit, the buggy code was removed in 3.5 in commit
7213cf2c and others.

Rajkumar changed code for handling channel switching in
mac80211 to stop the queues in

  commit 7cc44ed4
  Author: Rajkumar Manoharan <rmanohar@qca.qualcomm.com>
  Date:   Fri Sep 16 15:32:34 2011 +0530

      mac80211: Fix regression on queue stop during 2040 bss change

which went into 3.2. In the 3.4 cycle, Paul's change

  commit 3117bbdb
  Author: Paul Stewart <pstew@chromium.org>
  Date:   Tue Mar 13 07:46:18 2012 -0700

      mac80211: Don't let regulatory make us deaf

went in and changed the TX/RX enable logic, but now
the conditions for stopping and restarting the queues
were different so that now, if the AP changes between
20/40 MHz bandwidth, it can happen that we stop but
never restart the queues. This breaks the connection
and the module actually has to be reloaded to get it
back to work.

Fix this by making sure the queues are always started
when they were stopped.
Reported-by: Florian Manschwetus <manschwetus@googlemail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

net/mac80211/mlme.c

@@ -187,7 +187,7 @@ static u32 ieee80211_enable_ht(struct ieee80211_sub_if_data *sdata,
 	u32 changed = 0;
 	int hti_cfreq;
 	u16 ht_opmode;
-	bool enable_ht = true;
+	bool enable_ht = true, queues_stopped = false;
 	enum nl80211_channel_type prev_chantype;
 	enum nl80211_channel_type rx_channel_type = NL80211_CHAN_NO_HT;
 	enum nl80211_channel_type tx_channel_type;
@@ -254,6 +254,7 @@ static u32 ieee80211_enable_ht(struct ieee80211_sub_if_data *sdata,
 		 */
 		ieee80211_stop_queues_by_reason(&sdata->local->hw,
 				IEEE80211_QUEUE_STOP_REASON_CHTYPE_CHANGE);
+		queues_stopped = true;
 
 		/* flush out all packets */
 		synchronize_net();
@@ -272,12 +273,12 @@ static u32 ieee80211_enable_ht(struct ieee80211_sub_if_data *sdata,
 						 IEEE80211_RC_HT_CHANGED,
 						 tx_channel_type);
 		rcu_read_unlock();
-
-		if (beacon_htcap_ie)
-			ieee80211_wake_queues_by_reason(&sdata->local->hw,
-				IEEE80211_QUEUE_STOP_REASON_CHTYPE_CHANGE);
 	}
 
+	if (queues_stopped)
+		ieee80211_wake_queues_by_reason(&sdata->local->hw,
+			IEEE80211_QUEUE_STOP_REASON_CHTYPE_CHANGE);
+
 	ht_opmode = le16_to_cpu(hti->operation_mode);
 
 	/* if bss configuration changed store the new one */