On 03/08/2016 06:13 PM, Oliver Hartkopp wrote:
> As described in 'can: m_can: tag current CAN FD controllers as non-ISO'
> (6cfda7fbebe) it is possible to define fixed configuration options by
> setting the according bit in 'ctrlmode' and clear it in 'ctrlmode_supported'.
> This leads to the incovenience that the fixed configuration can not be passed
> by netlink (ip tool) even when it has the correct value (e.g. non-ISO, FD).
>
> This patch fixes that issue and allows fixed set bit values to be set again
> which does not change the unmodifiable content.
>
> Additionally it fixes the inconsitency that was prohibiting the support of
> 'CANFD-only' controller drivers.
>
> Reported-by: Ramesh Shanmugasundaram <ramesh.shanmugasundaram@xxxxxxxxxxxxxx>
> Signed-off-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx>
> Cc: linux-stable <stable@xxxxxxxxxxxxxxx> 3.16+
> ---
> drivers/net/can/dev.c | 16 +++++++++++++---
> 1 file changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c
> index 141c2a4..b084cfd 100644
> --- a/drivers/net/can/dev.c
> +++ b/drivers/net/can/dev.c
> @@ -696,11 +696,18 @@ int can_change_mtu(struct net_device *dev, int new_mtu)
> /* allow change of MTU according to the CANFD ability of the device */
> switch (new_mtu) {
> case CAN_MTU:
> + /* take care of 'CANFD-only' controllers */
> + if (!(priv->ctrlmode_supported & CAN_CTRLMODE_FD) &&
> + (priv->ctrlmode & CAN_CTRLMODE_FD))
> + return -EINVAL;
> +
> priv->ctrlmode &= ~CAN_CTRLMODE_FD;
> break;
>
> case CANFD_MTU:
> - if (!(priv->ctrlmode_supported & CAN_CTRLMODE_FD))
> + /* check for CANFD capability */
> + if (!(priv->ctrlmode_supported & CAN_CTRLMODE_FD) &&
> + !(priv->ctrlmode & CAN_CTRLMODE_FD))
> return -EINVAL;
>
> priv->ctrlmode |= CAN_CTRLMODE_FD;
> @@ -819,10 +826,13 @@ static int can_changelink(struct net_device *dev,
> return -EBUSY;
> cm = nla_data(data[IFLA_CAN_CTRLMODE]);
>
> - /* check whether changed bits are allowed to be modified */
> - if (cm->mask & ~priv->ctrlmode_supported)
> + /* check whether provided bits are allowed to be passed */
> + if (cm->mask & ~(priv->ctrlmode_supported | priv->ctrlmode))
> return -EOPNOTSUPP;
>
> + /* reduce to bits that are allowed to be modified */
> + cm->mask &= priv->ctrlmode_supported;
> +
I just realized that I'm updating a provided netlink attribute here.
Does anyone know, whether this is feasible OR if I need to spend an extra
variable to perform the '&=' operation?
Are netlink attributes to be treated as constants?
Thanks,
Oliver
> /* clear bits to be modified and copy the flag values */
> priv->ctrlmode &= ~cm->mask;
> priv->ctrlmode |= (cm->flags & cm->mask);
>
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