Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756591Ab2KNF4I (ORCPT ); Wed, 14 Nov 2012 00:56:08 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:55246 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756438Ab2KNFvF (ORCPT ); Wed, 14 Nov 2012 00:51:05 -0500 Message-Id: <20121114053939.141502299@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Wed, 14 Nov 2012 05:40:11 +0000 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Sven Eckelmann , Simon Wunderlich , Felix Fietkau , "John W. Linville" Subject: [ 38/82] ath9k: Test for TID only in BlockAcks while checking tx status In-Reply-To: <20121114053933.726869752@decadent.org.uk> X-SA-Exim-Connect-IP: 2001:470:1f08:1539:21c:bfff:fe03:f805 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2698 Lines: 71 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sven Eckelmann commit 6fe7cc71bbf3a0bc28c9cec3c00bc11e81344412 upstream. The ath9k xmit functions for AMPDUs can send frames as non-aggregate in case only one frame is currently available. The client will then answer using a normal Ack instead of a BlockAck. This acknowledgement has no TID stored and therefore the hardware is not able to provide us the corresponding TID. The TID set by the hardware in the tx status descriptor has to be seen as undefined and not as a valid TID value for normal acknowledgements. Doing otherwise results in a massive amount of retransmissions and stalls of connections. Users may experience low bandwidth and complete connection stalls in environments with transfers using multiple TIDs. This regression was introduced in b11b160defc48e4daa283f785192ea3a23a51f8e ("ath9k: validate the TID in the tx status information"). Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich Acked-by: Felix Fietkau Signed-off-by: John W. Linville [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- drivers/net/wireless/ath/ath9k/xmit.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/drivers/net/wireless/ath/ath9k/xmit.c +++ b/drivers/net/wireless/ath/ath9k/xmit.c @@ -370,7 +370,7 @@ static void ath_tx_complete_aggr(struct u16 seq_st = 0, acked_cnt = 0, txfail_cnt = 0; u32 ba[WME_BA_BMP_SIZE >> 5]; int isaggr, txfail, txpending, sendbar = 0, needreset = 0, nbad = 0; - bool rc_update = true; + bool rc_update = true, isba; struct ieee80211_tx_rate rates[4]; struct ath_frame_info *fi; int nframes; @@ -408,13 +408,17 @@ static void ath_tx_complete_aggr(struct an = (struct ath_node *)sta->drv_priv; tidno = ieee80211_get_qos_ctl(hdr)[0] & IEEE80211_QOS_CTL_TID_MASK; tid = ATH_AN_2_TID(an, tidno); + isba = ts->ts_flags & ATH9K_TX_BA; /* * The hardware occasionally sends a tx status for the wrong TID. * In this case, the BA status cannot be considered valid and all * subframes need to be retransmitted + * + * Only BlockAcks have a TID and therefore normal Acks cannot be + * checked */ - if (tidno != ts->tid) + if (isba && tidno != ts->tid) txok = false; isaggr = bf_isaggr(bf); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/