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- From: Michal Kazior <michal.kazior@tieto.com>
- Date: Mon, 25 Jan 2016 14:43:24 +0100
- Subject: [PATCH] mac80211: fix unnecessary frame drops in mesh fwding
- 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>
- ---
- --- a/net/mac80211/rx.c
- +++ b/net/mac80211/rx.c
- @@ -2235,7 +2235,7 @@ 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);
- @@ -2304,7 +2304,8 @@ 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;
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