Return-path: Received: from mail-lf0-f41.google.com ([209.85.215.41]:36616 "EHLO mail-lf0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755405AbcAYNmn (ORCPT ); Mon, 25 Jan 2016 08:42:43 -0500 Received: by mail-lf0-f41.google.com with SMTP id h129so85432654lfh.3 for ; Mon, 25 Jan 2016 05:42:42 -0800 (PST) From: Michal Kazior To: linux-wireless@vger.kernel.org Cc: johannes@sipsolutions.net, Michal Kazior Subject: [PATCH] mac80211: fix unnecessary frame drops in mesh fwding Date: Mon, 25 Jan 2016 14:43:24 +0100 Message-Id: <1453729404-26506-1-git-send-email-michal.kazior@tieto.com> (sfid-20160125_144246_965537_DE4B606F) Sender: linux-wireless-owner@vger.kernel.org List-ID: 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 --- net/mac80211/rx.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c index ae993edfdecf..664e8861edbe 100644 --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -2235,7 +2235,7 @@ ieee80211_rx_h_mesh_fwding(struct ieee80211_rx_data *rx) 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); @@ -2304,7 +2304,8 @@ ieee80211_rx_h_mesh_fwding(struct ieee80211_rx_data *rx) 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; -- 2.1.4