Revert: "rt2x00: Don't let mac80211 send a BAR when an AMPDU subframe fails"

This revert:

commit be03d4a45c09ee5100d3aaaedd087f19bc20d01f
Author: Andreas Hartmann <andihartmann@01019freenet.de>
Date:   Tue Apr 17 00:25:28 2012 +0200

    rt2x00: Don't let mac80211 send a BAR when an AMPDU subframe fails

To fix problem workaround by above commit use
IEEE80211_HW_TEARDOWN_AGGR_ON_BAR_FAIL flag (see change log for
"mac80211: introduce IEEE80211_HW_TEARDOWN_AGGR_ON_BAR_FAIL" patch).

Resolve: https://bugzilla.kernel.org/show_bug.cgi?id=42828
Bisected-by: Francisco Pina Martins <f.pinamartins@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/rt2x00/rt2800lib.c

@@ -5090,7 +5090,8 @@ static int rt2800_probe_hw_mode(struct rt2x00_dev *rt2x00dev)
 	    IEEE80211_HW_SUPPORTS_PS |
 	    IEEE80211_HW_PS_NULLFUNC_STACK |
 	    IEEE80211_HW_AMPDU_AGGREGATION |
-	    IEEE80211_HW_REPORTS_TX_ACK_STATUS;
+	    IEEE80211_HW_REPORTS_TX_ACK_STATUS |
+	    IEEE80211_HW_TEARDOWN_AGGR_ON_BAR_FAIL;
 
 	/*
 	 * Don't set IEEE80211_HW_HOST_BROADCAST_PS_BUFFERING for USB devices

drivers/net/wireless/rt2x00/rt2x00dev.c

@@ -392,10 +392,9 @@ void rt2x00lib_txdone(struct queue_entry *entry,
 		tx_info->flags |= IEEE80211_TX_STAT_AMPDU;
 		tx_info->status.ampdu_len = 1;
 		tx_info->status.ampdu_ack_len = success ? 1 : 0;
-		/*
-		 * TODO: Need to tear down BA session here
-		 * if not successful.
-		 */
+
+		if (!success)
+			tx_info->flags |= IEEE80211_TX_STAT_AMPDU_NO_BACK;
 	}
 
 	if (rate_flags & IEEE80211_TX_RC_USE_RTS_CTS) {