Bluetooth: Finish implementation for Rec RR (P=1) on ERTM

Now the code handles the case under SREJ_SENT state.
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
Reviewed-by: João Paulo Rechi Vita <jprvita@profusion.mobi>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/bluetooth/l2cap.c

@@ -3499,8 +3499,17 @@ static inline void l2cap_data_channel_rrframe(struct sock *sk, u16 rx_control)
 	l2cap_drop_acked_frames(sk);
 
 	if (rx_control & L2CAP_CTRL_POLL) {
-		l2cap_send_i_or_rr_or_rnr(sk);
-		pi->conn_state &= ~L2CAP_CONN_REMOTE_BUSY;
+		if (pi->conn_state & L2CAP_CONN_SREJ_SENT) {
+			if ((pi->conn_state & L2CAP_CONN_REMOTE_BUSY) &&
+					(pi->unacked_frames > 0))
+				__mod_retrans_timer();
+
+			pi->conn_state &= ~L2CAP_CONN_REMOTE_BUSY;
+			l2cap_send_srejtail(sk);
+		} else {
+			l2cap_send_i_or_rr_or_rnr(sk);
+			pi->conn_state &= ~L2CAP_CONN_REMOTE_BUSY;
+		}
 
 	} else if (rx_control & L2CAP_CTRL_FINAL) {
 		pi->conn_state &= ~L2CAP_CONN_REMOTE_BUSY;