[PATCH 1/3] can: c_can: exit c_can_do_tx() early if no frames have been sent

Dario Binacchi
2021-06-06T20:17:24Z

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.

Signed-off-by: Dario Binacchi <dariobin@libero.it>
---

drivers/net/can/c_can/c_can.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c
index 313793f6922d..2b203bf004f9 100644
--- a/drivers/net/can/c_can/c_can.c
+++ b/drivers/net/can/c_can/c_can.c
@@ -721,17 +721,18 @@ 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
--
2.17.1