Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932242AbcDZX1f (ORCPT ); Tue, 26 Apr 2016 19:27:35 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:41006 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754793AbcDZX1b (ORCPT ); Tue, 26 Apr 2016 19:27:31 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Johannes Berg" , "Michal Kazior" Date: Wed, 27 Apr 2016 01:02:21 +0200 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 039/217] mac80211: fix unnecessary frame drops in mesh fwding In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8426:ae4:c500:9cba:69ae:962d:6167 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: 2249 Lines: 65 3.16.35-rc1 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: Ben Hutchings --- net/mac80211/rx.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -2058,7 +2058,7 @@ ieee80211_rx_h_mesh_fwding(struct ieee80 struct ieee80211_sub_if_data *sdata = rx->sdata; struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb); 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); @@ -2128,7 +2128,8 @@ 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;