can: treewide: remove can_change_mtu()

can_change_mtu() became obsolete by commit 23049938605b ("can: populate the
minimum and maximum MTU values"). Now that net_device->min_mtu and
net_device->max_mtu are populated, all the checks are already done by
dev_validate_mtu() in net/core/dev.c.

Remove the net_device_ops->ndo_change_mtu() callback of all the physical
interfaces, then remove can_change_mtu(). Only keep the vcan_change_mtu()
and vxcan_change_mtu() because the virtual interfaces use their own
different MTU logic.

The only functional change this patch introduces is that now the user will
be able to change the MTU even if the interface is up. This does not matter
for Classical CAN and CAN FD because their MTU range is composed of only
one value, respectively CAN_MTU and CANFD_MTU. For the upcoming CAN XL, the
MTU will be configurable within the CANXL_MIN_MTU to CANXL_MAX_MTU range at
any time, even if the interface is up. This is consistent with the other
net protocols and does not contradict ISO 11898-1:2024 as having a
modifiable MTU is a kernel extension.

Signed-off-by: Vincent Mailhol <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Marc Kleine-Budde <[e-mail]>

drivers/net/can/at91_can.c

···
 	.ndo_open	= at91_open,
 	.ndo_stop	= at91_close,
 	.ndo_start_xmit	= at91_start_xmit,
-	.ndo_change_mtu = can_change_mtu,
 };
 
 static const struct ethtool_ops at91_ethtool_ops = {

drivers/net/can/bxcan.c

···
 	.ndo_open = bxcan_open,
 	.ndo_stop = bxcan_stop,
 	.ndo_start_xmit = bxcan_start_xmit,
-	.ndo_change_mtu = can_change_mtu,
 };
 
 static const struct ethtool_ops bxcan_ethtool_ops = {

drivers/net/can/c_can/c_can_main.c

···
 	.ndo_open = c_can_open,
 	.ndo_stop = c_can_close,
 	.ndo_start_xmit = c_can_start_xmit,
-	.ndo_change_mtu = can_change_mtu,
 };
 
 int register_c_can_dev(struct net_device *dev)

drivers/net/can/can327.c

···
 	.ndo_open = can327_netdev_open,
 	.ndo_stop = can327_netdev_close,
 	.ndo_start_xmit = can327_netdev_start_xmit,
-	.ndo_change_mtu = can_change_mtu,
 };
 
 static const struct ethtool_ops can327_ethtool_ops = {

drivers/net/can/cc770/cc770.c

···
 	.ndo_open = cc770_open,
 	.ndo_stop = cc770_close,
 	.ndo_start_xmit = cc770_start_xmit,
-	.ndo_change_mtu = can_change_mtu,
 };
 
 static const struct ethtool_ops cc770_ethtool_ops = {

drivers/net/can/ctucanfd/ctucanfd_base.c

···
 	.ndo_open	= ctucan_open,
 	.ndo_stop	= ctucan_close,
 	.ndo_start_xmit	= ctucan_start_xmit,
-	.ndo_change_mtu	= can_change_mtu,
 };
 
 static const struct ethtool_ops ctucan_ethtool_ops = {

drivers/net/can/dev/dev.c

···
 	}
 }
 
-/* changing MTU and control mode for CAN/CANFD devices */
-int can_change_mtu(struct net_device *dev, int new_mtu)
-{
-	struct can_priv *priv = netdev_priv(dev);
-	u32 ctrlmode_static = can_get_static_ctrlmode(priv);
-
-	/* Do not allow changing the MTU while running */
-	if (dev->flags & IFF_UP)
-		return -EBUSY;
-
-	/* allow change of MTU according to the CANFD ability of the device */
-	switch (new_mtu) {
-	case CAN_MTU:
-		/* 'CANFD-only' controllers can not switch to CAN_MTU */
-		if (ctrlmode_static & CAN_CTRLMODE_FD)
-			return -EINVAL;
-
-		priv->ctrlmode &= ~CAN_CTRLMODE_FD;
-		break;
-
-	case CANFD_MTU:
-		/* check for potential CANFD ability */
-		if (!(priv->ctrlmode_supported & CAN_CTRLMODE_FD) &&
-		    !(ctrlmode_static & CAN_CTRLMODE_FD))
-			return -EINVAL;
-
-		priv->ctrlmode |= CAN_CTRLMODE_FD;
-		break;
-
-	default:
-		return -EINVAL;
-	}
-
-	WRITE_ONCE(dev->mtu, new_mtu);
-	return 0;
-}
-EXPORT_SYMBOL_GPL(can_change_mtu);
-
 /* helper to define static CAN controller features at device creation time */
 int can_set_static_ctrlmode(struct net_device *dev, u32 static_mode)
 {

drivers/net/can/esd/esd_402_pci-core.c

···
 	.ndo_open = acc_open,
 	.ndo_stop = acc_close,
 	.ndo_start_xmit = acc_start_xmit,
-	.ndo_change_mtu = can_change_mtu,
 	.ndo_eth_ioctl = can_eth_ioctl_hwts,
 };
 

drivers/net/can/flexcan/flexcan-core.c

···
 	.ndo_open	= flexcan_open,
 	.ndo_stop	= flexcan_close,
 	.ndo_start_xmit	= flexcan_start_xmit,
-	.ndo_change_mtu = can_change_mtu,
 };
 
 static int register_flexcandev(struct net_device *dev)

drivers/net/can/grcan.c

···
 	.ndo_open	= grcan_open,
 	.ndo_stop	= grcan_close,
 	.ndo_start_xmit	= grcan_start_xmit,
-	.ndo_change_mtu = can_change_mtu,
 };
 
 static const struct ethtool_ops grcan_ethtool_ops = {

drivers/net/can/ifi_canfd/ifi_canfd.c

···
 	.ndo_open	= ifi_canfd_open,
 	.ndo_stop	= ifi_canfd_close,
 	.ndo_start_xmit	= ifi_canfd_start_xmit,
-	.ndo_change_mtu	= can_change_mtu,
 };
 
 static const struct ethtool_ops ifi_canfd_ethtool_ops = {

drivers/net/can/janz-ican3.c

···
 	.ndo_open	= ican3_open,
 	.ndo_stop	= ican3_stop,
 	.ndo_start_xmit	= ican3_xmit,
-	.ndo_change_mtu = can_change_mtu,
 };
 
 static const struct ethtool_ops ican3_ethtool_ops = {

drivers/net/can/kvaser_pciefd/kvaser_pciefd_core.c

···
 	.ndo_stop = kvaser_pciefd_stop,
 	.ndo_eth_ioctl = can_eth_ioctl_hwts,
 	.ndo_start_xmit = kvaser_pciefd_start_xmit,
-	.ndo_change_mtu = can_change_mtu,
 };
 
 static int kvaser_pciefd_set_phys_id(struct net_device *netdev,

drivers/net/can/m_can/m_can.c

···
 	.ndo_open = m_can_open,
 	.ndo_stop = m_can_close,
 	.ndo_start_xmit = m_can_start_xmit,
-	.ndo_change_mtu = can_change_mtu,
 };
 
 static int m_can_get_coalesce(struct net_device *dev,

drivers/net/can/mscan/mscan.c

···
 	.ndo_open	= mscan_open,
 	.ndo_stop	= mscan_close,
 	.ndo_start_xmit	= mscan_start_xmit,
-	.ndo_change_mtu	= can_change_mtu,
 };
 
 static const struct ethtool_ops mscan_ethtool_ops = {

drivers/net/can/peak_canfd/peak_canfd.c

···
 	.ndo_stop = peak_canfd_close,
 	.ndo_eth_ioctl = peak_eth_ioctl,
 	.ndo_start_xmit = peak_canfd_start_xmit,
-	.ndo_change_mtu = can_change_mtu,
 };
 
 static int peak_get_ts_info(struct net_device *dev,

drivers/net/can/rcar/rcar_can.c

···
 	.ndo_open = rcar_can_open,
 	.ndo_stop = rcar_can_close,
 	.ndo_start_xmit = rcar_can_start_xmit,
-	.ndo_change_mtu = can_change_mtu,
 };
 
 static const struct ethtool_ops rcar_can_ethtool_ops = {

drivers/net/can/rcar/rcar_canfd.c

···
 	.ndo_open = rcar_canfd_open,
 	.ndo_stop = rcar_canfd_close,
 	.ndo_start_xmit = rcar_canfd_start_xmit,
-	.ndo_change_mtu = can_change_mtu,
 };
 
 static const struct ethtool_ops rcar_canfd_ethtool_ops = {

drivers/net/can/rockchip/rockchip_canfd-core.c

···
 	.ndo_open = rkcanfd_open,
 	.ndo_stop = rkcanfd_stop,
 	.ndo_start_xmit = rkcanfd_start_xmit,
-	.ndo_change_mtu = can_change_mtu,
 };
 
 static int __maybe_unused rkcanfd_runtime_suspend(struct device *dev)

drivers/net/can/sja1000/sja1000.c

···
 	.ndo_open	= sja1000_open,
 	.ndo_stop	= sja1000_close,
 	.ndo_start_xmit	= sja1000_start_xmit,
-	.ndo_change_mtu	= can_change_mtu,
 };
 
 static const struct ethtool_ops sja1000_ethtool_ops = {

drivers/net/can/slcan/slcan-core.c

···
 	.ndo_open               = slcan_netdev_open,
 	.ndo_stop               = slcan_netdev_close,
 	.ndo_start_xmit         = slcan_netdev_xmit,
-	.ndo_change_mtu         = can_change_mtu,
 };
 
 /******************************************

drivers/net/can/softing/softing_main.c

···
 	.ndo_open = softing_netdev_open,
 	.ndo_stop = softing_netdev_stop,
 	.ndo_start_xmit	= softing_netdev_start_xmit,
-	.ndo_change_mtu = can_change_mtu,
 };
 
 static const struct ethtool_ops softing_ethtool_ops = {

drivers/net/can/spi/hi311x.c

···
 	.ndo_open = hi3110_open,
 	.ndo_stop = hi3110_stop,
 	.ndo_start_xmit = hi3110_hard_start_xmit,
-	.ndo_change_mtu = can_change_mtu,
 };
 
 static const struct ethtool_ops hi3110_ethtool_ops = {

drivers/net/can/spi/mcp251x.c

···
 	.ndo_open = mcp251x_open,
 	.ndo_stop = mcp251x_stop,
 	.ndo_start_xmit = mcp251x_hard_start_xmit,
-	.ndo_change_mtu = can_change_mtu,
 };
 
 static const struct ethtool_ops mcp251x_ethtool_ops = {

drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c

···
 	.ndo_stop = mcp251xfd_stop,
 	.ndo_start_xmit	= mcp251xfd_start_xmit,
 	.ndo_eth_ioctl = can_eth_ioctl_hwts,
-	.ndo_change_mtu = can_change_mtu,
 };
 
 static void

drivers/net/can/sun4i_can.c

···
 	.ndo_open = sun4ican_open,
 	.ndo_stop = sun4ican_close,
 	.ndo_start_xmit = sun4ican_start_xmit,
-	.ndo_change_mtu = can_change_mtu,
 };
 
 static const struct ethtool_ops sun4ican_ethtool_ops = {

drivers/net/can/ti_hecc.c

···
 	.ndo_open		= ti_hecc_open,
 	.ndo_stop		= ti_hecc_close,
 	.ndo_start_xmit		= ti_hecc_xmit,
-	.ndo_change_mtu		= can_change_mtu,
 };
 
 static const struct ethtool_ops ti_hecc_ethtool_ops = {

drivers/net/can/usb/ems_usb.c

···
 	.ndo_open = ems_usb_open,
 	.ndo_stop = ems_usb_close,
 	.ndo_start_xmit = ems_usb_start_xmit,
-	.ndo_change_mtu = can_change_mtu,
 };
 
 static const struct ethtool_ops ems_usb_ethtool_ops = {

drivers/net/can/usb/esd_usb.c

···
 	.ndo_open = esd_usb_open,
 	.ndo_stop = esd_usb_close,
 	.ndo_start_xmit = esd_usb_start_xmit,
-	.ndo_change_mtu = can_change_mtu,
 };
 
 static const struct ethtool_ops esd_usb_ethtool_ops = {

drivers/net/can/usb/etas_es58x/es58x_core.c

···
 	.ndo_stop = es58x_stop,
 	.ndo_start_xmit = es58x_start_xmit,
 	.ndo_eth_ioctl = can_eth_ioctl_hwts,
-	.ndo_change_mtu = can_change_mtu,
 };
 
 static const struct ethtool_ops es58x_ethtool_ops = {

drivers/net/can/usb/f81604.c

···
 	.ndo_open = f81604_open,
 	.ndo_stop = f81604_close,
 	.ndo_start_xmit = f81604_start_xmit,
-	.ndo_change_mtu = can_change_mtu,
 };
 
 static const struct can_bittiming_const f81604_bittiming_const = {

drivers/net/can/usb/gs_usb.c

···
 	.ndo_open = gs_can_open,
 	.ndo_stop = gs_can_close,
 	.ndo_start_xmit = gs_can_start_xmit,
-	.ndo_change_mtu = can_change_mtu,
 	.ndo_eth_ioctl = gs_can_eth_ioctl,
 };
 

drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c

···
 	.ndo_stop = kvaser_usb_close,
 	.ndo_eth_ioctl = can_eth_ioctl_hwts,
 	.ndo_start_xmit = kvaser_usb_start_xmit,
-	.ndo_change_mtu = can_change_mtu,
 };
 
 static const struct ethtool_ops kvaser_usb_ethtool_ops = {

drivers/net/can/usb/mcba_usb.c

···
 	.ndo_open = mcba_usb_open,
 	.ndo_stop = mcba_usb_close,
 	.ndo_start_xmit = mcba_usb_start_xmit,
-	.ndo_change_mtu = can_change_mtu,
 };
 
 static const struct ethtool_ops mcba_ethtool_ops = {

drivers/net/can/usb/nct6694_canfd.c

···
 	.ndo_open = nct6694_canfd_open,
 	.ndo_stop = nct6694_canfd_close,
 	.ndo_start_xmit = nct6694_canfd_start_xmit,
-	.ndo_change_mtu = can_change_mtu,
 };
 
 static const struct ethtool_ops nct6694_canfd_ethtool_ops = {

drivers/net/can/usb/peak_usb/pcan_usb_core.c

···
 	.ndo_stop = peak_usb_ndo_stop,
 	.ndo_eth_ioctl = peak_eth_ioctl,
 	.ndo_start_xmit = peak_usb_ndo_start_xmit,
-	.ndo_change_mtu = can_change_mtu,
 };
 
 /* CAN-USB devices generally handle 32-bit CAN channel IDs.

drivers/net/can/usb/ucan.c

···
 	.ndo_open = ucan_open,
 	.ndo_stop = ucan_close,
 	.ndo_start_xmit = ucan_start_xmit,
-	.ndo_change_mtu = can_change_mtu,
 };
 
 static const struct ethtool_ops ucan_ethtool_ops = {

drivers/net/can/usb/usb_8dev.c

···
 	.ndo_open = usb_8dev_open,
 	.ndo_stop = usb_8dev_close,
 	.ndo_start_xmit = usb_8dev_start_xmit,
-	.ndo_change_mtu = can_change_mtu,
 };
 
 static const struct ethtool_ops usb_8dev_ethtool_ops = {

drivers/net/can/xilinx_can.c

···
 	.ndo_open	= xcan_open,
 	.ndo_stop	= xcan_close,
 	.ndo_start_xmit	= xcan_start_xmit,
-	.ndo_change_mtu	= can_change_mtu,
 };
 
 static const struct ethtool_ops xcan_ethtool_ops = {

include/linux/can/dev.h

···
 int open_candev(struct net_device *dev);
 void close_candev(struct net_device *dev);
 void can_set_default_mtu(struct net_device *dev);
-int can_change_mtu(struct net_device *dev, int new_mtu);
 int __must_check can_set_static_ctrlmode(struct net_device *dev,
 					 u32 static_mode);
 int can_eth_ioctl_hwts(struct net_device *netdev, struct ifreq *ifr, int cmd);