[PATCH 4/5] wifi: ath12k: fix MLO beacon handling using per-link addressing

[Jose Ignacio Tornos Martinez]

ath12k_mac_handle_beacon_iter() uses ahvif->deflink for both BSSID
matching and connection_loss_work cancellation. In MLO, deflink is
only the first link created for the MLD VIF and does not represent
the other links. This causes two problems:

1. Beacon BSSID matching only checks deflink's BSS config
   (vif->bss_conf.bssid), so beacons received on non-deflink links
   never match and never cancel connection_loss_work.

2. Only deflink's connection_loss_work is cancelled, leaving
   non-deflink connection_loss_work timers running even when beacons
   are being received normally.

When the firmware reports a beacon miss event on any link,
ath12k_mac_handle_beacon_miss() queues connection_loss_work on that
link with a 3-second timeout. If a beacon is received before the
timeout, ath12k_mac_handle_beacon_iter() should cancel it. But the
deflink-only handling means that for non-deflink MLO links, beacons
are never matched and connection_loss_work is never cancelled through
this path.

Fix by handling non-MLO and MLO cases separately. For non-MLO, keep
the existing deflink behavior. For MLO, iterate all active links to
match the beacon BSSID against each link's BSS config. When a match
is found, cancel connection_loss_work on all links because the
work callback calls per-VIF ieee80211_connection_loss() regardless
of which link queued it.

Tested on WCN7850 with MLO (Wi-Fi 7).

Signed-off-by: Jose Ignacio Tornos Martinez <jtornosm@xxxxxxxxxx>
---
 drivers/net/wireless/ath/ath12k/mac.c | 36 ++++++++++++++++++++++++---
 1 file changed, 32 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/ath/ath12k/mac.c b/drivers/net/wireless/ath/ath12k/mac.c
index e36a37852fab..ebc35636b4ef 100644
--- a/drivers/net/wireless/ath/ath12k/mac.c
+++ b/drivers/net/wireless/ath/ath12k/mac.c
@@ -1946,15 +1946,43 @@ static void ath12k_mac_handle_beacon_iter(void *data, u8 *mac,
 	struct sk_buff *skb = data;
 	struct ieee80211_mgmt *mgmt = (void *)skb->data;
 	struct ath12k_vif *ahvif = ath12k_vif_to_ahvif(vif);
-	struct ath12k_link_vif *arvif = &ahvif->deflink;
+	struct ieee80211_bss_conf *link_conf;
+	struct ath12k_link_vif *arvif;
+	unsigned long links;
+	u8 link_id;
 
-	if (vif->type != NL80211_IFTYPE_STATION || !arvif->is_created)
+	if (vif->type != NL80211_IFTYPE_STATION)
 		return;
 
-	if (!ether_addr_equal(mgmt->bssid, vif->bss_conf.bssid))
+	if (!ieee80211_vif_is_mld(vif)) {
+		arvif = &ahvif->deflink;
+		if (arvif->is_created &&
+		    ether_addr_equal(mgmt->bssid, vif->bss_conf.bssid))
+			cancel_delayed_work(&arvif->connection_loss_work);
 		return;
+	}
 
-	cancel_delayed_work(&arvif->connection_loss_work);
+	/* For MLO, each link has a different AP BSSID. Check the beacon
+	 * against all link BSS configs. If any matches, cancel
+	 * connection_loss_work on all links since it calls per-VIF
+	 * ieee80211_connection_loss() regardless of which link queued it.
+	 */
+	links = ahvif->links_map;
+	for_each_set_bit(link_id, &links, IEEE80211_MLD_MAX_NUM_LINKS) {
+		link_conf = rcu_dereference(vif->link_conf[link_id]);
+		if (link_conf &&
+		    ether_addr_equal(mgmt->bssid, link_conf->bssid))
+			goto found;
+	}
+
+	return;
+
+found:
+	for_each_set_bit(link_id, &links, IEEE80211_MLD_MAX_NUM_LINKS) {
+		arvif = rcu_dereference(ahvif->link[link_id]);
+		if (arvif && arvif->is_created)
+			cancel_delayed_work(&arvif->connection_loss_work);
+	}
 }
 
 void ath12k_mac_handle_beacon(struct ath12k *ar, struct sk_buff *skb)
-- 
2.54.0