On Sat. 14 Aug 2021 at 20:12, Marc Kleine-Budde [off-list ref] wrote:

On 14.08.2021 18:17:48, Vincent Mailhol wrote:
[...]

quoted

 static int can_changelink(struct net_device *dev, struct nlattr *tb[],
                        struct nlattr *data[],
                        struct netlink_ext_ack *extack)
 {
      struct can_priv *priv = netdev_priv(dev);
+     u32 tdc_mask = 0;
      int err;

      /* We need synchronization with dev->stop() */

@@ -107,6 +179,7 @@ static int can_changelink(struct net_device *dev, struct nlattr *tb[],
              struct can_ctrlmode *cm;
              u32 ctrlstatic;
              u32 maskedflags;
+             u32 tdc_flags;

              /* Do not allow changing controller mode while running */
              if (dev->flags & IFF_UP)

@@ -138,7 +211,18 @@ static int can_changelink(struct net_device *dev, struct nlattr *tb[],
                      dev->mtu = CAN_MTU;
                      memset(&priv->data_bittiming, 0,
                             sizeof(priv->data_bittiming));
+                     memset(&priv->tdc, 0, sizeof(priv->tdc));
+                     priv->ctrlmode &= ~CAN_CTRLMODE_TDC_MASK;
              }
+
+             tdc_flags = cm->flags & CAN_CTRLMODE_TDC_MASK;
+             /* CAN_CTRLMODE_TDC_{AUTO,MANUAL} are mutually exclusive */
+             if (tdc_flags == CAN_CTRLMODE_TDC_MASK)
+                     return -EOPNOTSUPP;
+             /* If one of CAN_CTRLMODE_TDC_* is set then TDC must be set */
+             if (tdc_flags && !data[IFLA_CAN_TDC])
+                     return -EOPNOTSUPP;

These don't need information form the can_priv, right? So these checks
can be moved to can_validate()?

ACK. Actually, this comment applies not only to can_changelink()
but also to can_tdc_changelink().  I just sent a v5 where I made
sure to move all the checks that do not rely on can_priv to
can_validate().


Yours sincerely,
Vincent