[PATCH mt76-next 15/27] wifi: mt76: mt7996: keep a returning link when adding station links fails

[Felix Fietkau <nbd@nbd.name>]

mt7996_mac_sta_add_links() removes all links that it was asked to add,
with flush set, when one of them fails. A link that comes back after
a removal kept its msta_link and may still have a firmware entry. The
flush frees its msta_link and returns its WTBL index to wcid_mask, so a
later station can be given an index whose entry still belongs to this
station.

Flush only the links that this call created, and remove a returning
link again without flush.

Fixes: e8c819df0243 ("wifi: mt76: mt7996: Destroy active sta links in mt7996_mac_sta_remove()")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
 drivers/net/wireless/mediatek/mt76/mt7996/main.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/main.c b/drivers/net/wireless/mediatek/mt76/mt7996/main.c
index 8e70a4061ed6..58a487549ddf 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7996/main.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7996/main.c
@@ -1355,6 +1355,7 @@ mt7996_mac_sta_add_links(struct mt7996_dev *dev, struct ieee80211_vif *vif,
 			 struct ieee80211_sta *sta, unsigned long new_links)
 {
 	struct mt7996_sta *msta = (struct mt7996_sta *)sta->drv_priv;
+	unsigned long created = 0, returned = 0;
 	unsigned int link_id;
 	int err = 0;
 
@@ -1372,6 +1373,7 @@ mt7996_mac_sta_add_links(struct mt7996_dev *dev, struct ieee80211_vif *vif,
 				mt7996_sta_deflink_set(sta, link_id,
 						       msta_link->wcid.idx);
 			msta->seclink_id = mt7996_sta_seclink_get(dev, msta);
+			returned |= BIT(link_id);
 			continue;
 		}
 
@@ -1405,12 +1407,14 @@ mt7996_mac_sta_add_links(struct mt7996_dev *dev, struct ieee80211_vif *vif,
 			goto error_unlink;
 
 		mphy->num_sta++;
+		created |= BIT(link_id);
 	}
 
 	return 0;
 
 error_unlink:
-	mt7996_mac_sta_remove_links(dev, vif, sta, new_links, true);
+	mt7996_mac_sta_remove_links(dev, vif, sta, created, true);
+	mt7996_mac_sta_remove_links(dev, vif, sta, returned, false);
 
 	return err;
 }
-- 
2.47.3