lkml.org 
[lkml]   [2020]   [Nov]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.19 017/101] can: dev: __can_get_echo_skb(): fix real payload length return value for RTR frames
    Date
    From: Oliver Hartkopp <socketcan@hartkopp.net>

    [ Upstream commit ed3320cec279407a86bc4c72edc4a39eb49165ec ]

    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>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/net/can/dev.c | 8 ++++++--
    1 file changed, 6 insertions(+), 2 deletions(-)

    diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c
    index be532eb64baa2..1950b13f22dfc 100644
    --- a/drivers/net/can/dev.c
    +++ b/drivers/net/can/dev.c
    @@ -493,9 +493,13 @@ struct sk_buff *__can_get_echo_skb(struct net_device *dev, unsigned int idx, u8
    */
    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;
    --
    2.27.0


    \
     
     \ /
      Last update: 2020-11-17 15:10    [W:4.036 / U:0.012 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site