can: c_can: exit c_can_do_tx() early if no frames have been sent

The c_can_poll() handles RX/TX events unconditionally. It may therefore
happen that c_can_do_tx() is called unnecessarily because the interrupt
was triggered by the reception of a frame. In these cases, we avoid to
execute unnecessary statements and exit immediately.

Link: https://lore.kernel.org/r/20210807130800.5246-3-dariobin@libero.it
Signed-off-by: Dario Binacchi <dariobin@libero.it>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/drivers/net/can/c_can/c_can_main.c b/drivers/net/can/c_can/c_can_main.c
index 052ff35ed4dcafb9a956fc188646de124a094d4c..1ec0ce664732d805225a7c54d0eea0d3d83e6524 100644 (file)
--- a/drivers/net/can/c_can/c_can_main.c
+++ b/drivers/net/can/c_can/c_can_main.c
@@ -720,17 +720,18 @@ static void c_can_do_tx(struct net_device *dev)
                pkts++;
        }
 
+       if (!pkts)
+               return;
+
        /* Clear the bits in the tx_active mask */
        atomic_sub(clr, &priv->tx_active);
 
        if (clr & BIT(priv->msg_obj_tx_num - 1))
                netif_wake_queue(dev);
 
-       if (pkts) {
-               stats->tx_bytes += bytes;
-               stats->tx_packets += pkts;
-               can_led_event(dev, CAN_LED_EVENT_TX);
-       }
+       stats->tx_bytes += bytes;
+       stats->tx_packets += pkts;
+       can_led_event(dev, CAN_LED_EVENT_TX);
 }
 
 /* If we have a gap in the pending bits, that means we either