[PATCH v2] dummy_can: fix packet statistics

[PATCH v2] dummy_can: fix packet statistics

[Oliver Hartkopp]

The former implementation was only counting the tx_packets value but not
the tx_bytes as the skb was dropped on driver layer.
By enabling the CAN echo support (IFF_ECHO) in dummy_can_init() the code
to put and get the echo skb is activated and the tx_bytes are counted
correctly.

Fixes: 816cf430e84b ("can: add dummy_can driver")
Cc: Vincent Mailhol <mailhol@kernel.org>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
---
 drivers/net/can/dummy_can.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/can/dummy_can.c b/drivers/net/can/dummy_can.c
index 41953655e3d3..cd23de488edc 100644
--- a/drivers/net/can/dummy_can.c
+++ b/drivers/net/can/dummy_can.c
@@ -239,10 +239,11 @@ static int __init dummy_can_init(void)
 	if (!dev)
 		return -ENOMEM;
 
 	dev->netdev_ops = &dummy_can_netdev_ops;
 	dev->ethtool_ops = &dummy_can_ethtool_ops;
+	dev->flags |= IFF_ECHO; /* enable echo handling */
 	priv = netdev_priv(dev);
 	priv->can.bittiming_const = &dummy_can_bittiming_const;
 	priv->can.bitrate_max = 20 * MEGA /* BPS */;
 	priv->can.clock.freq = 160 * MEGA /* Hz */;
 	priv->can.fd.data_bittiming_const = &dummy_can_fd_databittiming_const;
-- 
2.47.3

Re: [PATCH v2] dummy_can: fix packet statistics

[Vincent Mailhol]

On 26/01/2026 at 11:45, Oliver Hartkopp wrote:
> The former implementation was only counting the tx_packets value but not
> the tx_bytes as the skb was dropped on driver layer.
> By enabling the CAN echo support (IFF_ECHO) in dummy_can_init() the code
> to put and get the echo skb is activated and the tx_bytes are counted
> correctly.
> 
> Fixes: 816cf430e84b ("can: add dummy_can driver")
> Cc: Vincent Mailhol <mailhol@kernel.org>
> Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>

Reviewed-by: Vincent Mailhol <mailhol@kernel.org>


Yours sincerely,
Vincent Mailhol

Re: [PATCH v2] dummy_can: fix packet statistics

[Marc Kleine-Budde]

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On 26.01.2026 11:45:40, Oliver Hartkopp wrote:
> The former implementation was only counting the tx_packets value but not
> the tx_bytes as the skb was dropped on driver layer.
> By enabling the CAN echo support (IFF_ECHO) in dummy_can_init() the code
> to put and get the echo skb is activated and the tx_bytes are counted
> correctly.
>
> Fixes: 816cf430e84b ("can: add dummy_can driver")
> Cc: Vincent Mailhol <mailhol@kernel.org>
> Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>

Applied to linux-can.

Thanks,
Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde          |
Embedded Linux                   | https://www.pengutronix.de |
Vertretung Nürnberg              | Phone: +49-5121-206917-129 |
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Re: [PATCH v2] dummy_can: fix packet statistics

[Marc Kleine-Budde]

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On 26.01.2026 11:45:40, Oliver Hartkopp wrote:
> The former implementation was only counting the tx_packets value but not
> the tx_bytes as the skb was dropped on driver layer.
> By enabling the CAN echo support (IFF_ECHO) in dummy_can_init() the code
> to put and get the echo skb is activated and the tx_bytes are counted
> correctly.

Re-phrased the commit message to make it more imperative:

    can: dummy_can: dummy_can_init(): fix packet statistics

    The former implementation was only counting the tx_packets value but not
    the tx_bytes as the skb was dropped on driver layer.

    Enable CAN echo support (IFF_ECHO) in dummy_can_init(), which activates the
    code for setting and retrieving the echo SKB and counts the tx_bytes
    correctly.

regards,
Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde          |
Embedded Linux                   | https://www.pengutronix.de |
Vertretung Nürnberg              | Phone: +49-5121-206917-129 |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-9   |

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