wil6210: fix race condition of disconnect while BACK event

This race condition was causing double free of tid_ampdu_rx structures
Signed-off-by: Dedy Lansky <qca_dlansky@qca.qualcomm.com>
Signed-off-by: Vladimir Kondratiev <qca_vkondrat@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/wil6210/wmi.c

@@ -597,16 +597,18 @@ static void wmi_evt_ba_status(struct wil6210_priv *wil, int id, void *d,
 		return;
 	}
 
+	mutex_lock(&wil->mutex);
+
 	cid = wil->vring2cid_tid[evt->ringid][0];
 	if (cid >= WIL6210_MAX_CID) {
 		wil_err(wil, "invalid CID %d for vring %d\n", cid, evt->ringid);
-		return;
+		goto out;
 	}
 
 	sta = &wil->sta[cid];
 	if (sta->status == wil_sta_unused) {
 		wil_err(wil, "CID %d unused\n", cid);
-		return;
+		goto out;
 	}
 
 	wil_dbg_wmi(wil, "BACK for CID %d %pM\n", cid, sta->addr);
@@ -618,6 +620,9 @@ static void wmi_evt_ba_status(struct wil6210_priv *wil, int id, void *d,
 			sta->tid_rx[i] = wil_tid_ampdu_rx_alloc(wil,
 						evt->agg_wsize, 0);
 	}
+
+out:
+	mutex_unlock(&wil->mutex);
 }
 
 static const struct {