| From 859ae7018316daa4adbc496012dcbbb458d7e510 Mon Sep 17 00:00:00 2001 |
| From: Nicolas Escande <nico.escande@gmail.com> |
| Date: Mon, 14 Feb 2022 18:32:14 +0100 |
| Subject: mac80211: fix forwarded mesh frames AC & queue selection |
| |
| From: Nicolas Escande <nico.escande@gmail.com> |
| |
| commit 859ae7018316daa4adbc496012dcbbb458d7e510 upstream. |
| |
| There are two problems with the current code that have been highlighted |
| with the AQL feature that is now enbaled by default. |
| |
| First problem is in ieee80211_rx_h_mesh_fwding(), |
| ieee80211_select_queue_80211() is used on received packets to choose |
| the sending AC queue of the forwarding packet although this function |
| should only be called on TX packet (it uses ieee80211_tx_info). |
| This ends with forwarded mesh packets been sent on unrelated random AC |
| queue. To fix that, AC queue can directly be infered from skb->priority |
| which has been extracted from QOS info (see ieee80211_parse_qos()). |
| |
| Second problem is the value of queue_mapping set on forwarded mesh |
| frames via skb_set_queue_mapping() is not the AC of the packet but a |
| hardware queue index. This may or may not work depending on AC to HW |
| queue mapping which is driver specific. |
| |
| Both of these issues lead to improper AC selection while forwarding |
| mesh packets but more importantly due to improper airtime accounting |
| (which is done on a per STA, per AC basis) caused traffic stall with |
| the introduction of AQL. |
| |
| Fixes: cf44012810cc ("mac80211: fix unnecessary frame drops in mesh fwding") |
| Fixes: d3c1597b8d1b ("mac80211: fix forwarded mesh frame queue mapping") |
| Co-developed-by: Remi Pommarel <repk@triplefau.lt> |
| Signed-off-by: Remi Pommarel <repk@triplefau.lt> |
| Signed-off-by: Nicolas Escande <nico.escande@gmail.com> |
| Link: https://lore.kernel.org/r/20220214173214.368862-1-nico.escande@gmail.com |
| Signed-off-by: Johannes Berg <johannes.berg@intel.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| net/mac80211/rx.c | 4 ++-- |
| 1 file changed, 2 insertions(+), 2 deletions(-) |
| |
| --- a/net/mac80211/rx.c |
| +++ b/net/mac80211/rx.c |
| @@ -2852,13 +2852,13 @@ ieee80211_rx_h_mesh_fwding(struct ieee80 |
| ether_addr_equal(sdata->vif.addr, hdr->addr3)) |
| return RX_CONTINUE; |
| |
| - ac = ieee80211_select_queue_80211(sdata, skb, hdr); |
| + ac = ieee802_1d_to_ac[skb->priority]; |
| 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; |
| } |
| - skb_set_queue_mapping(skb, q); |
| + skb_set_queue_mapping(skb, ac); |
| |
| if (!--mesh_hdr->ttl) { |
| if (!is_multicast_ether_addr(hdr->addr1)) |