mac80211: avoid transmitting delBA to old AP

When roaming while we have active BA session,
we can end up transmitting delBA frames to
the old AP while we're already on the new AP's
channel, which can cause warnings.

Simply avoid sending those frames, but still
tear down the internal session state, since
they are not really necessary anyway as we
will implicitly disassociate when sending the
association to the new AP.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/sta_info.h

@@ -79,6 +79,7 @@ enum ieee80211_sta_info_flags {
  * @dialog_token: dialog token for aggregation session
  * @state: session state (see above)
  * @stop_initiator: initiator of a session stop
+ * @tx_stop: TX DelBA frame when stopping
  *
  * This structure is protected by RCU and the per-station
  * spinlock. Assignments to the array holding it must hold
@@ -95,6 +96,7 @@ struct tid_ampdu_tx {
 	unsigned long state;
 	u8 dialog_token;
 	u8 stop_initiator;
+	bool tx_stop;
 };
 
 /**