Bluetooth: hci_conn: Make unacked packet handling more robust

This attempts to make unacked packet handling more robust by detecting
if there are no connections left then restore all buffers of the
respective pool.

Fixes: 5638d9e ("Bluetooth: hci_conn: Fix not restoring ISO buffer count on disconnect")
Signed-off-by: Luiz Augusto von Dentz <[email protected]>

Author: Vudentz

net/bluetooth/hci_conn.c

@@ -149,8 +149,6 @@ static void hci_conn_cleanup(struct hci_conn *conn)
 
 	hci_chan_list_flush(conn);
 
-	hci_conn_hash_del(hdev, conn);
-
 	if (HCI_CONN_HANDLE_UNSET(conn->handle))
 		ida_free(&hdev->unset_handle_ida, conn->handle);
 
@@ -1152,28 +1150,54 @@ void hci_conn_del(struct hci_conn *conn)
 	disable_delayed_work_sync(&conn->auto_accept_work);
 	disable_delayed_work_sync(&conn->idle_work);
 
-	if (conn->type == ACL_LINK) {
-		/* Unacked frames */
-		hdev->acl_cnt += conn->sent;
-	} else if (conn->type == LE_LINK) {
-		cancel_delayed_work(&conn->le_conn_timeout);
+	/* Remove the connection from the list so unacked logic can detect when
+	 * a certain pool is not being utilized.
+	 */
+	hci_conn_hash_del(hdev, conn);
 
-		if (hdev->le_pkts)
-			hdev->le_cnt += conn->sent;
+	/* Handle unacked frames:
+	 *
+	 * - In case there are no connection, or if restoring the buffers
+	 *   considered in transist would overflow, restore all buffers to the
+	 *   pool.
+	 * - Otherwise restore just the buffers considered in transit for the
+	 *   hci_conn
+	 */
+	switch (conn->type) {
+	case ACL_LINK:
+		if (!hci_conn_num(hdev, ACL_LINK) ||
+		    hdev->acl_cnt + conn->sent > hdev->acl_pkts)
+			hdev->acl_cnt = hdev->acl_pkts;
 		else
 			hdev->acl_cnt += conn->sent;
-	} else {
-		/* Unacked ISO frames */
-		if (conn->type == CIS_LINK ||
-		    conn->type == BIS_LINK ||
-		    conn->type == PA_LINK) {
-			if (hdev->iso_pkts)
-				hdev->iso_cnt += conn->sent;
-			else if (hdev->le_pkts)
+		break;
+	case LE_LINK:
+		cancel_delayed_work(&conn->le_conn_timeout);
+
+		if (hdev->le_pkts) {
+			if (!hci_conn_num(hdev, LE_LINK) ||
+			    hdev->le_cnt + conn->sent > hdev->le_pkts)
+				hdev->le_cnt = hdev->le_pkts;
+			else
 				hdev->le_cnt += conn->sent;
+		} else {
+			if ((!hci_conn_num(hdev, LE_LINK) &&
+			     !hci_conn_num(hdev, ACL_LINK)) ||
+			    hdev->acl_cnt + conn->sent > hdev->acl_pkts)
+				hdev->acl_cnt = hdev->acl_pkts;
 			else
 				hdev->acl_cnt += conn->sent;
 		}
+		break;
+	case CIS_LINK:
+	case BIS_LINK:
+	case PA_LINK:
+		if (!hci_iso_count(hdev) ||
+		    hdev->iso_cnt + conn->sent > hdev->iso_pkts)
+			hdev->iso_cnt = hdev->iso_pkts;
+		else
+			hdev->iso_cnt += conn->sent;
+		break;
 	}
 
 	skb_queue_purge(&conn->data_q);