diff mbox series

[net,06/27] can: dev: __can_get_echo_skb(): fix real payload length return value for RTR frames

Message ID 20201103220636.972106-7-mkl@pengutronix.de (mailing list archive)
State Not Applicable
Delegated to: Netdev Maintainers
Headers show
Series pull-request: can 2020-11-03 | expand

Commit Message

Marc Kleine-Budde Nov. 3, 2020, 10:06 p.m. UTC 
From: Oliver Hartkopp <socketcan@hartkopp.net>

The can_get_echo_skb() function returns the number of received bytes to
be used for netdev statistics. In the case of RTR frames we get a valid
(potential non-zero) data length value which has to be passed for further
operations. But on the wire RTR frames have no payload length. Therefore
the value to be used in the statistics has to be zero for RTR frames.

Reported-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Link: https://lore.kernel.org/r/20201020064443.80164-1-socketcan@hartkopp.net
Fixes: cf5046b309b3 ("can: dev: let can_get_echo_skb() return dlc of CAN frame")
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 drivers/net/can/dev.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c
index 73cfcd7e9517..6dee4f8f2024 100644
--- a/drivers/net/can/dev.c
+++ b/drivers/net/can/dev.c
@@ -512,9 +512,13 @@  __can_get_echo_skb(struct net_device *dev, unsigned int idx, u8 *len_ptr)
 		 */
 		struct sk_buff *skb = priv->echo_skb[idx];
 		struct canfd_frame *cf = (struct canfd_frame *)skb->data;
-		u8 len = cf->len;
 
-		*len_ptr = len;
+		/* get the real payload length for netdev statistics */
+		if (cf->can_id & CAN_RTR_FLAG)
+			*len_ptr = 0;
+		else
+			*len_ptr = cf->len;
+
 		priv->echo_skb[idx] = NULL;
 
 		return skb;