| From | Kamal Mostafa <> | Subject | [PATCH 4.2.y-ckt 200/218] mac80211: fix unnecessary frame drops in mesh fwding | Date | Thu, 31 Mar 2016 13:16:53 -0700 |
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4.2.8-ckt7 -stable review patch. If anyone has any objections, please let me know.
---8<------------------------------------------------------------
From: Michal Kazior <michal.kazior@tieto.com>
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 <michal.kazior@tieto.com> Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- 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 c06f40d6..3250527 100644 --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -2213,7 +2213,7 @@ 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); @@ -2282,7 +2282,8 @@ 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; -- 2.7.4
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