[PATCH mt76-next 01/25] wifi: mt76: mt7996: take the link of an 802.3 frame from its station

[Felix Fietkau <nbd@nbd.name>]

mt7996_tx_prepare_skb() takes the link of every frame other than the
QoS data of an MLO station from IEEE80211_TX_CTRL_MLO_LINK. mac80211
does not set that field for 802.3 frames, as include/net/mac80211.h
documents, so it reads 0.

Since commit 729c83a3330c ("wifi: mt76: mt7996: fix reading zeroed
info->control.flags after mt76_tx_status_skb_add()"),
mt7996_mac_write_txwi() uses that link instead of the link of the wcid.
When the host writes the TXD of an 802.3 frame to a non-MLO station on
a link other than 0, the TXD thus names the BSS and band of link 0, and
the frame is lost.

Treat an 802.3 frame like one with IEEE80211_LINK_UNSPECIFIED, so that
it takes the link of its wcid, as before that commit.

Fixes: 729c83a3330c ("wifi: mt76: mt7996: fix reading zeroed info->control.flags after mt76_tx_status_skb_add()")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
 drivers/net/wireless/mediatek/mt76/mt7996/mac.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/mac.c b/drivers/net/wireless/mediatek/mt76/mt7996/mac.c
index f36da545045b..edff4e5a5dff 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7996/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7996/mac.c
@@ -1062,6 +1062,9 @@ int mt7996_tx_prepare_skb(struct mt76_dev *mdev, void *txwi_ptr,
 		u8 tid = tx_info->skb->priority & IEEE80211_QOS_CTL_TID_MASK;
 
 		link_id = (tid % 2) ? msta->seclink_id : msta->deflink_id;
+	} else if (is_8023) {
+		/* mac80211 does not set the MLO link of an 802.3 frame */
+		link_id = IEEE80211_LINK_UNSPECIFIED;
 	} else {
 		link_id = u32_get_bits(info->control.flags,
 				       IEEE80211_TX_CTRL_MLO_LINK);
-- 
2.47.3