wifi: mt76: scan: set vif offchannel link for scanning/roc

The driver needs to know what vif link to use

Link: https://patch.msgid.link/20250311103646.43346-4-nbd@nbd.name
Signed-off-by: Felix Fietkau <nbd@nbd.name>

Author: nbd168

drivers/net/wireless/mediatek/mt76/channel.c

@@ -293,6 +293,7 @@ struct mt76_vif_link *mt76_get_vif_phy_link(struct mt76_phy *phy,
 		kfree(mlink);
 		return ERR_PTR(ret);
 	}
+	rcu_assign_pointer(mvif->offchannel_link, mlink);
 
 	return mlink;
 }
@@ -301,10 +302,12 @@ void mt76_put_vif_phy_link(struct mt76_phy *phy, struct ieee80211_vif *vif,
 			   struct mt76_vif_link *mlink)
 {
 	struct mt76_dev *dev = phy->dev;
+	struct mt76_vif_data *mvif = mlink->mvif;
 
 	if (IS_ERR_OR_NULL(mlink) || !mlink->offchannel)
 		return;
 
+	rcu_assign_pointer(mvif->offchannel_link, NULL);
 	dev->drv->vif_link_remove(phy, vif, &vif->bss_conf, mlink);
 	kfree(mlink);
 }

drivers/net/wireless/mediatek/mt76/mt76.h

@@ -351,6 +351,7 @@ struct mt76_wcid {
 	u8 hw_key_idx;
 	u8 hw_key_idx2;
 
+	u8 offchannel:1;
 	u8 sta:1;
 	u8 sta_disabled:1;
 	u8 amsdu:1;
@@ -787,6 +788,7 @@ struct mt76_vif_link {
 
 struct mt76_vif_data {
 	struct mt76_vif_link __rcu *link[IEEE80211_MLD_MAX_NUM_LINKS];
+	struct mt76_vif_link __rcu *offchannel_link;
 
 	struct mt76_phy *roc_phy;
 	u16 valid_links;