can: netlink: add can_bittiming_const_fill_info()

Add function can_bittiming_const_fill_info() to factorise the logic
when filling the bittiming constant information for Classical CAN and
CAN FD. This function will be reused later on for CAN XL.

Signed-off-by: Vincent Mailhol <mailhol@kernel.org>
Link: https://patch.msgid.link/20250923-canxl-netlink-prep-v4-15-e720d28f66fe@kernel.org
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

Author: vincent-mailhol

drivers/net/can/dev/netlink.c

@@ -567,6 +567,15 @@ static int can_bittiming_fill_info(struct sk_buff *skb, int ifla_can_bittiming,
 		nla_put(skb, ifla_can_bittiming, sizeof(*bittiming), bittiming);
 }
 
+static int can_bittiming_const_fill_info(struct sk_buff *skb,
+					 int ifla_can_bittiming_const,
+					 const struct can_bittiming_const *bittiming_const)
+{
+	return bittiming_const &&
+		nla_put(skb, ifla_can_bittiming_const,
+			sizeof(*bittiming_const), bittiming_const);
+}
+
 static int can_tdc_fill_info(struct sk_buff *skb, const struct net_device *dev)
 {
 	struct nlattr *nest;
@@ -652,9 +661,8 @@ static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
 	if (can_bittiming_fill_info(skb, IFLA_CAN_BITTIMING,
 				    &priv->bittiming) ||
 
-	    (priv->bittiming_const &&
-	     nla_put(skb, IFLA_CAN_BITTIMING_CONST,
-		     sizeof(*priv->bittiming_const), priv->bittiming_const)) ||
+	    can_bittiming_const_fill_info(skb, IFLA_CAN_BITTIMING_CONST,
+					  priv->bittiming_const) ||
 
 	    nla_put(skb, IFLA_CAN_CLOCK, sizeof(priv->clock), &priv->clock) ||
 	    nla_put_u32(skb, IFLA_CAN_STATE, state) ||
@@ -668,10 +676,8 @@ static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
 	    can_bittiming_fill_info(skb, IFLA_CAN_DATA_BITTIMING,
 				    &priv->fd.data_bittiming) ||
 
-	    (priv->fd.data_bittiming_const &&
-	     nla_put(skb, IFLA_CAN_DATA_BITTIMING_CONST,
-		     sizeof(*priv->fd.data_bittiming_const),
-		     priv->fd.data_bittiming_const)) ||
+	    can_bittiming_const_fill_info(skb, IFLA_CAN_DATA_BITTIMING_CONST,
+					  priv->fd.data_bittiming_const) ||
 
 	    (priv->termination_const &&
 	     (nla_put_u16(skb, IFLA_CAN_TERMINATION, priv->termination) ||