[PATCH mt76-next 13/27] wifi: mt76: mt7996: make a returning link primary if a station has none

[Felix Fietkau <nbd@nbd.name>]

mt7996_mac_sta_remove_link() clears deflink_id when it removes the
primary link and no secondary link is left to take its place. If the
removed link then comes back, mt7996_mac_sta_add_links() finds its
existing msta_link and only marks it valid again. deflink_id stays
IEEE80211_LINK_UNSPECIFIED, so the station has no primary link: the TXQs
keep the WLAN index that they had before, seclink_id stays unspecified,
mt7996_sta_rate_ctrl_update() finds no primary link, and
mt7996_sta_set_4addr() treats every link as a secondary link.

Make a returning link the primary link when the station has none, in
the same way as mt7996_mac_sta_init_link() does for a new link. Move the
two steps that set the primary link, and the switch to the secondary
link on removal, to helpers.

Fixes: e8c819df0243 ("wifi: mt76: mt7996: Destroy active sta links in mt7996_mac_sta_remove()")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
 .../net/wireless/mediatek/mt76/mt7996/main.c  | 55 +++++++++++++------
 1 file changed, 37 insertions(+), 18 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/main.c b/drivers/net/wireless/mediatek/mt76/mt7996/main.c
index 9de455939125..8f483b1de852 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7996/main.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7996/main.c
@@ -1133,6 +1133,38 @@ mt7996_sta_init_txq_wcid(struct ieee80211_sta *sta, int idx)
 	}
 }
 
+static void
+mt7996_sta_deflink_set(struct ieee80211_sta *sta, unsigned int link_id,
+		       int idx)
+{
+	struct mt7996_sta *msta = (struct mt7996_sta *)sta->drv_priv;
+
+	msta->deflink_id = link_id;
+	mt7996_sta_init_txq_wcid(sta, idx);
+}
+
+static void
+mt7996_sta_deflink_release(struct mt7996_dev *dev, struct ieee80211_sta *sta,
+			   unsigned int link_id)
+{
+	struct mt7996_sta *msta = (struct mt7996_sta *)sta->drv_priv;
+	struct mt7996_sta_link *msta_seclink;
+
+	if (msta->deflink_id != link_id)
+		return;
+
+	msta->deflink_id = IEEE80211_LINK_UNSPECIFIED;
+	if (msta->seclink_id == link_id)
+		return;
+
+	/* switch to the secondary link */
+	msta_seclink = mt76_dereference(msta->link[msta->seclink_id],
+					&dev->mt76);
+	if (msta_seclink)
+		mt7996_sta_deflink_set(sta, msta->seclink_id,
+				       msta_seclink->wcid.idx);
+}
+
 static u8
 mt7996_sta_seclink_get(struct mt7996_dev *dev, struct mt7996_sta *msta)
 {
@@ -1180,8 +1212,7 @@ mt7996_mac_sta_init_link(struct mt7996_dev *dev,
 
 	if (msta->deflink_id == IEEE80211_LINK_UNSPECIFIED) {
 		msta_link = &msta->deflink;
-		msta->deflink_id = link_id;
-		mt7996_sta_init_txq_wcid(sta, idx);
+		mt7996_sta_deflink_set(sta, link_id, idx);
 	} else {
 		msta_link = kzalloc_obj(*msta_link);
 		if (!msta_link) {
@@ -1242,22 +1273,7 @@ void mt7996_mac_sta_remove_link(struct mt7996_dev *dev,
 		mt7996_mac_wtbl_update(dev, msta_link->wcid.idx,
 				       MT_WTBL_UPDATE_ADM_COUNT_CLEAR);
 
-		if (msta->deflink_id == link_id) {
-			msta->deflink_id = IEEE80211_LINK_UNSPECIFIED;
-			if (msta->seclink_id != link_id) {
-				struct mt7996_sta_link *msta_seclink;
-
-				/* switch to the secondary link */
-				msta_seclink = mt76_dereference(
-						msta->link[msta->seclink_id],
-						&dev->mt76);
-				if (msta_seclink) {
-					msta->deflink_id = msta->seclink_id;
-					mt7996_sta_init_txq_wcid(sta,
-						msta_seclink->wcid.idx);
-				}
-			}
-		}
+		mt7996_sta_deflink_release(dev, sta, link_id);
 		msta_link->wcid.link_valid = false;
 		msta->seclink_id = mt7996_sta_seclink_get(dev, msta);
 	}
@@ -1336,6 +1352,9 @@ mt7996_mac_sta_add_links(struct mt7996_dev *dev, struct ieee80211_vif *vif,
 		msta_link = mt76_dereference(msta->link[link_id], &dev->mt76);
 		if (msta_link) {
 			msta_link->wcid.link_valid = true;
+			if (msta->deflink_id == IEEE80211_LINK_UNSPECIFIED)
+				mt7996_sta_deflink_set(sta, link_id,
+						       msta_link->wcid.idx);
 			msta->seclink_id = mt7996_sta_seclink_get(dev, msta);
 			continue;
 		}
-- 
2.47.3