Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754099AbcDRDRo (ORCPT ); Sun, 17 Apr 2016 23:17:44 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:36248 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753476AbcDRCe1 (ORCPT ); Sun, 17 Apr 2016 22:34:27 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Michal Kazior , Johannes Berg Subject: [PATCH 4.5 090/124] mac80211: fix unnecessary frame drops in mesh fwding Date: Mon, 18 Apr 2016 11:29:22 +0900 Message-Id: <20160418022620.362891984@linuxfoundation.org> X-Mailer: git-send-email 2.8.0 In-Reply-To: <20160418022615.726954227@linuxfoundation.org> References: <20160418022615.726954227@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2246 Lines: 67 4.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: Michal Kazior commit cf44012810ccdd8fd947518e965cb04b7b8498be upstream. The ieee80211_queue_stopped() expects hw queue number but it was given raw WMM AC number instead. This could cause frame drops and problems with traffic in some cases - most notably if driver doesn't map AC numbers to queue numbers 1:1 and uses ieee80211_stop_queues() and ieee80211_wake_queue() only without ever calling ieee80211_wake_queues(). On ath10k it was possible to hit this problem in the following case: 1. wlan0 uses queue 0 (ath10k maps queues per vif) 2. offchannel uses queue 15 3. queues 1-14 are unused 4. ieee80211_stop_queues() 5. ieee80211_wake_queue(q=0) 6. ieee80211_wake_queue(q=15) (other queues are not woken up because both driver and mac80211 know other queues are unused) 7. ieee80211_rx_h_mesh_fwding() 8. ieee80211_select_queue_80211() returns 2 9. ieee80211_queue_stopped(q=2) returns true 10. frame is dropped (oops!) Fixes: d3c1597b8d1b ("mac80211: fix forwarded mesh frame queue mapping") Signed-off-by: Michal Kazior Signed-off-by: Johannes Berg Signed-off-by: Greg Kroah-Hartman --- net/mac80211/rx.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -2249,7 +2249,7 @@ ieee80211_rx_h_mesh_fwding(struct ieee80 struct ieee80211_local *local = rx->local; struct ieee80211_sub_if_data *sdata = rx->sdata; struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh; - u16 q, hdrlen; + u16 ac, q, hdrlen; hdr = (struct ieee80211_hdr *) skb->data; hdrlen = ieee80211_hdrlen(hdr->frame_control); @@ -2318,7 +2318,8 @@ ieee80211_rx_h_mesh_fwding(struct ieee80 ether_addr_equal(sdata->vif.addr, hdr->addr3)) return RX_CONTINUE; - q = ieee80211_select_queue_80211(sdata, skb, hdr); + ac = ieee80211_select_queue_80211(sdata, skb, hdr); + q = sdata->vif.hw_queue[ac]; if (ieee80211_queue_stopped(&local->hw, q)) { IEEE80211_IFSTA_MESH_CTR_INC(ifmsh, dropped_frames_congestion); return RX_DROP_MONITOR;