[openwrt/openwrt] mac80211: fix traffic stalls on forwarded mesh packets due to wrong AC selection

[LEDE Commits]

nbd pushed a commit to openwrt/openwrt.git, branch master:
https://git.openwrt.org/eae0dbf68cb973d7b629d65c3a2645ccaef7410a

commit eae0dbf68cb973d7b629d65c3a2645ccaef7410a
Author: Felix Fietkau <nbd at nbd.name>
AuthorDate: Tue Feb 15 15:16:31 2022 +0100

    mac80211: fix traffic stalls on forwarded mesh packets due to wrong AC selection
    
    Signed-off-by: Felix Fietkau <nbd at nbd.name>
---
 ...x-forwarded-mesh-frames-AC-queue-selectio.patch | 50 ++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/package/kernel/mac80211/patches/subsys/322-mac80211-fix-forwarded-mesh-frames-AC-queue-selectio.patch b/package/kernel/mac80211/patches/subsys/322-mac80211-fix-forwarded-mesh-frames-AC-queue-selectio.patch
new file mode 100644
index 0000000000..50693f7232
--- /dev/null
+++ b/package/kernel/mac80211/patches/subsys/322-mac80211-fix-forwarded-mesh-frames-AC-queue-selectio.patch
@@ -0,0 +1,50 @@
+From: Nicolas Escande <nico.escande at gmail.com>
+Date: Mon, 14 Feb 2022 18:32:14 +0100
+Subject: [PATCH] mac80211: fix forwarded mesh frames AC & queue selection
+
+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 at triplefau.lt>
+Signed-off-by: Remi Pommarel <repk at triplefau.lt>
+Signed-off-by: Nicolas Escande <nico.escande at gmail.com>
+---
+
+--- a/net/mac80211/rx.c
++++ b/net/mac80211/rx.c
+@@ -2921,13 +2921,13 @@ 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))