wifi: mt76: mt7996: set vif default link_id adding/removing vif links

This info will be consumed by subsequent patches (e.g. in set/get tsf
routines).

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://patch.msgid.link/20250312-b4-mt7996-mlo-p2-v1-18-015b3d6fd928@kernel.org
Signed-off-by: Felix Fietkau <nbd@nbd.name>

Author: LorenzoBianconi

drivers/net/wireless/mediatek/mt76/mt7996/main.c

@@ -271,6 +271,7 @@ int mt7996_vif_link_add(struct mt76_phy *mphy, struct ieee80211_vif *vif,
 			struct mt76_vif_link *mlink)
 {
 	struct mt7996_vif_link *link = container_of(mlink, struct mt7996_vif_link, mt76);
+	struct mt7996_vif *mvif = (struct mt7996_vif *)vif->drv_priv;
 	struct mt7996_sta_link *msta_link = &link->msta_link;
 	struct mt7996_phy *phy = mphy->priv;
 	struct mt7996_dev *dev = phy->dev;
@@ -338,6 +339,9 @@ int mt7996_vif_link_add(struct mt76_phy *mphy, struct ieee80211_vif *vif,
 
 	ieee80211_iter_keys(mphy->hw, vif, mt7996_key_iter, NULL);
 
+	if (mvif->mt76.deflink_id == IEEE80211_LINK_UNSPECIFIED)
+		mvif->mt76.deflink_id = link_conf->link_id;
+
 	return 0;
 }
 
@@ -346,6 +350,7 @@ void mt7996_vif_link_remove(struct mt76_phy *mphy, struct ieee80211_vif *vif,
 			    struct mt76_vif_link *mlink)
 {
 	struct mt7996_vif_link *link = container_of(mlink, struct mt7996_vif_link, mt76);
+	struct mt7996_vif *mvif = (struct mt7996_vif *)vif->drv_priv;
 	struct mt7996_sta_link *msta_link = &link->msta_link;
 	struct mt7996_phy *phy = mphy->priv;
 	struct mt7996_dev *dev = phy->dev;
@@ -359,6 +364,19 @@ void mt7996_vif_link_remove(struct mt76_phy *mphy, struct ieee80211_vif *vif,
 
 	rcu_assign_pointer(dev->mt76.wcid[idx], NULL);
 
+	if (mvif->mt76.deflink_id == link_conf->link_id) {
+		struct ieee80211_bss_conf *iter;
+		unsigned int link_id;
+
+		mvif->mt76.deflink_id = IEEE80211_LINK_UNSPECIFIED;
+		for_each_vif_active_link(vif, iter, link_id) {
+			if (link_id != IEEE80211_LINK_UNSPECIFIED) {
+				mvif->mt76.deflink_id = link_id;
+				break;
+			}
+		}
+	}
+
 	dev->mt76.vif_mask &= ~BIT_ULL(mlink->idx);
 	phy->omac_mask &= ~BIT_ULL(mlink->omac_idx);
 
@@ -443,6 +461,7 @@ static int mt7996_add_interface(struct ieee80211_hw *hw,
 	mt76_vif_init(vif, &mvif->mt76);
 
 	vif->offload_flags |= IEEE80211_OFFLOAD_ENCAP_4ADDR;
+	mvif->mt76.deflink_id = IEEE80211_LINK_UNSPECIFIED;
 
 out:
 	mutex_unlock(&dev->mt76.mutex);