[PATCH RFC 0/5] can: rework the CAN MTU logic

[PATCH RFC 0/5] can: rework the CAN MTU logic

[Vincent Mailhol]

---
RFC preface:

I am sending this as an RFC because I am not done 100% with my testing
and this depends on the other series I just sent earlier today:

Link: https://lore.kernel.org/linux-can/20250918-can-fix-mtu-v1-0-0d1cada9393b@kernel.org/

I will drop the RFC tag once the above series is merged and appears in
net-next.
---

The CAN MTU logic is currently broken. can_change_mtu() will update
both the MTU and the CAN_CTRLMODE_FD flag.

Back then, commit bc05a8944a34 ("can: allow to change the device mtu
for CAN FD capable devices") stated that:

  The configuration can be done either with the 'fd { on | off }'
  option in the 'ip' tool from iproute2 or by setting the CAN
  netdevice MTU to CAN_MTU (16) or to CANFD_MTU (72).

  Link: https://git.kernel.org/torvalds/c/bc05a8944a34

The problem is that after doing for example:

  $ ip link set can0 mtu 72 bittiming 500000

on a CAN FD interface, we are left with a device on which CAN FD is
enabled but which does not have the FD databittiming parameters
configured.

The same goes on when setting the mtu back to 16:

  ip link set can0 type can bitrate 500000 fd on dbitrate 5000000
  ip link set can0 mtu 16

The device is now in Classical CAN mode but iproute2 is still
reporting the databittiming values (although this time, the issue
seems less critical as it is only a reporting problem).

The only way to resolve the problem and bring the device back to a
coherent state is to call again the netlink interface using the
"fd on" or "fd off" options.

The idea of being able to infer the CAN_CTRLMODE_FD flag from the MTU
value is just incorrect for physical devices. Note that this logic
remains valid on virtual interfaces (vcan and vxcan) because those do
not have control mode flags and thus no conflict occurs.

This series reworks the CAN MTU logic. The goal is to always maintain
a coherent state between the MTU and the control mode flags as listed
in below table:

		fd off, xl off		fd on, xl off		fd any, xl on
  ---------------------------------------------------------------------------
  default mtu	CAN_MTU			CANFD_MTU		CANXL_MTU
  min mtu	CAN_MTU			CANFD_MTU		CANXL_MIN_MTU
  max mtu	CAN_MTU			CANFD_MTU		CANXL_MAX_MTU

In order to switch between one column to another, the user must use
the fd/xl on/off flags. Directly modifying the MTU from one column to
the other is not permitted any more.

The CAN XL is not yet supported at the moment, so the last column is
just given as a reference to better understand what is coming up. This
series will just implement the first two columns.

While doing the rewrite, the logic is adjusted to reuse as much as
possible the net core infrastructure. By populating:

  net_device->min_mtu

and

  net_device->max_mtu

the net core infrastructure will automatically:
    
  1. validate that the user's inputs are in range.

  2. report those min and max MTU values through the netlink
     interface.
    
Point 1. allows us to get rid of the can_change_mtu() for all the
physical devices and point 2. allows the end user to see the valid MTU
range by doing a:

  $ ip --details link show can0

Finally, because using the net core, it will be possible to modify the
MTU while the device is up. As stated previously, the only
modifications allowed will be within the MTU range of a given MTU. So
for Classical CAN and CAN FD, the MTU is fixed to, respectively,
CAN_MTU and CANFD_MTU. For the upcoming CAN XL, the user will be able
to change the MTU to anything between CANXL_MIN_MTU and CANXL_MAX_MTU
even if the device is up.

The first patch of this series annotates the read access on
net_device->mtu. This preparation is needed to prevent any race
condition to occur when modifying the MTU while the device is up.

The second patch is another preparation change which moves
can_set_static_ctrlmode() from dev.h to dev.c.

The third patch populates the MTU minimum and maximum value.

The fourth patch is just a clean-up to remove the old
can_change_mtu().

The fifth and last patch comes as a bonus content and modifies the
default MTU of the vcan and vxcan so that CAN XL is on by default.

To: Oliver Hartkopp <socketcan@hartkopp.net>
To: Marc Kleine-Budde <mkl@pengutronix.de>
Cc: linux-can@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Vincent Mailhol <mailhol@kernel.org>

---
Vincent Mailhol (5):
      can: annotate mtu accesses with READ_ONCE()
      can: dev: turn can_set_static_ctrlmode() into a non-inline function
      can: populate the minimum and maximum MTU values
      can: treewide: remove can_change_mtu()
      can: enable CAN XL for virtual CAN devices by default

 drivers/net/can/at91_can.c                         |  1 -
 drivers/net/can/bxcan.c                            |  1 -
 drivers/net/can/c_can/c_can_main.c                 |  1 -
 drivers/net/can/can327.c                           |  1 -
 drivers/net/can/cc770/cc770.c                      |  1 -
 drivers/net/can/ctucanfd/ctucanfd_base.c           |  1 -
 drivers/net/can/dev/dev.c                          | 54 +++++++++++-----------
 drivers/net/can/dev/netlink.c                      |  9 ++--
 drivers/net/can/esd/esd_402_pci-core.c             |  1 -
 drivers/net/can/flexcan/flexcan-core.c             |  1 -
 drivers/net/can/grcan.c                            |  1 -
 drivers/net/can/ifi_canfd/ifi_canfd.c              |  1 -
 drivers/net/can/janz-ican3.c                       |  1 -
 drivers/net/can/kvaser_pciefd/kvaser_pciefd_core.c |  1 -
 drivers/net/can/m_can/m_can.c                      |  1 -
 drivers/net/can/mscan/mscan.c                      |  1 -
 drivers/net/can/peak_canfd/peak_canfd.c            |  1 -
 drivers/net/can/rcar/rcar_can.c                    |  1 -
 drivers/net/can/rcar/rcar_canfd.c                  |  1 -
 drivers/net/can/rockchip/rockchip_canfd-core.c     |  1 -
 drivers/net/can/sja1000/sja1000.c                  |  1 -
 drivers/net/can/slcan/slcan-core.c                 |  1 -
 drivers/net/can/softing/softing_main.c             |  1 -
 drivers/net/can/spi/hi311x.c                       |  1 -
 drivers/net/can/spi/mcp251x.c                      |  1 -
 drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c     |  1 -
 drivers/net/can/sun4i_can.c                        |  1 -
 drivers/net/can/ti_hecc.c                          |  1 -
 drivers/net/can/usb/ems_usb.c                      |  1 -
 drivers/net/can/usb/esd_usb.c                      |  1 -
 drivers/net/can/usb/etas_es58x/es58x_core.c        |  1 -
 drivers/net/can/usb/f81604.c                       |  1 -
 drivers/net/can/usb/gs_usb.c                       |  1 -
 drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c   |  1 -
 drivers/net/can/usb/mcba_usb.c                     |  1 -
 drivers/net/can/usb/peak_usb/pcan_usb_core.c       |  1 -
 drivers/net/can/usb/ucan.c                         |  1 -
 drivers/net/can/usb/usb_8dev.c                     |  1 -
 drivers/net/can/vcan.c                             |  2 +-
 drivers/net/can/vxcan.c                            |  2 +-
 drivers/net/can/xilinx_can.c                       |  1 -
 include/linux/can/dev.h                            | 25 ++--------
 net/can/af_can.c                                   |  2 +-
 net/can/isotp.c                                    |  2 +-
 net/can/raw.c                                      |  2 +-
 45 files changed, 38 insertions(+), 97 deletions(-)
---
base-commit: 5e87fdc37f8dc619549d49ba5c951b369ce7c136
change-id: 20250915-can-fix-mtu-050a94b563a0
prerequisite-change-id: 20250918-can-fix-mtu-b521e1ed1a29:v1
prerequisite-patch-id: ace4f8ad663553a2a04ec56ca28fd2445b0ce06e
prerequisite-patch-id: 10ebdab5a42d989075b951bba3e93b5bea178ead
prerequisite-patch-id: 11502adb20b40227221185c363cd4f0733ca2239
prerequisite-patch-id: be9ed4f4caaa323a1757a7c5d4d2a4bfb2cfc124

Best regards,
-- 
Vincent Mailhol <mailhol@kernel.org>

[PATCH RFC 1/5] can: annotate mtu accesses with READ_ONCE()

[Vincent Mailhol]

As hinted in commit 501a90c94510 ("inet: protect against too small mtu
values."), net_device->mtu is vulnerable to race conditions if it is
written and read without holding the RTNL.

At the moment, all the writes are done while the interface is down, so
there are no such issues yet. But upcoming changes will allow to
modify the MTU while the CAN XL devices are up.

In preparation to the introduction of CAN XL, annotate all the
net_device->mtu accesses which are not yet guarded by the RTNL with a
READ_ONCE().

Note that all the write accesses are already either guarded by the
RTNL or are already annotated and thus need no changes.

Signed-off-by: Vincent Mailhol <mailhol@kernel.org>
---
 net/can/af_can.c | 2 +-
 net/can/isotp.c  | 2 +-
 net/can/raw.c    | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/can/af_can.c b/net/can/af_can.c
index b2387a46794a576973f3d865a5ca8e2ba696d167..770173d8db42813d5c085248d1bcf5fbe717955b 100644
--- a/net/can/af_can.c
+++ b/net/can/af_can.c
@@ -221,7 +221,7 @@ int can_send(struct sk_buff *skb, int loop)
 	}
 
 	/* Make sure the CAN frame can pass the selected CAN netdevice. */
-	if (unlikely(skb->len > skb->dev->mtu)) {
+	if (unlikely(skb->len > READ_ONCE(skb->dev->mtu))) {
 		err = -EMSGSIZE;
 		goto inval_skb;
 	}
diff --git a/net/can/isotp.c b/net/can/isotp.c
index dee1412b3c9c1ffcfc43a109b448701459fcf8b9..74ee1e52249b232813a06c5d2c6e404a38dce990 100644
--- a/net/can/isotp.c
+++ b/net/can/isotp.c
@@ -1313,7 +1313,7 @@ static int isotp_bind(struct socket *sock, struct sockaddr *uaddr, int len)
 		err = -ENODEV;
 		goto out;
 	}
-	if (dev->mtu < so->ll.mtu) {
+	if (READ_ONCE(dev->mtu) < so->ll.mtu) {
 		dev_put(dev);
 		err = -EINVAL;
 		goto out;
diff --git a/net/can/raw.c b/net/can/raw.c
index 76b867d21def209f5c6d236604c0e434a1c55a4d..6cb959e3dcd3e54972628ee59572a749009d1323 100644
--- a/net/can/raw.c
+++ b/net/can/raw.c
@@ -950,7 +950,7 @@ static int raw_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
 	err = -EINVAL;
 
 	/* check for valid CAN (CC/FD/XL) frame content */
-	txmtu = raw_check_txframe(ro, skb, dev->mtu);
+	txmtu = raw_check_txframe(ro, skb, READ_ONCE(dev->mtu));
 	if (!txmtu)
 		goto free_skb;
 

-- 
2.49.1

[PATCH RFC 2/5] can: dev: turn can_set_static_ctrlmode() into a non-inline function

[Vincent Mailhol]

can_set_static_ctrlmode() is declared as a static inline. But it is
only called in the probe function of the devices and so does not
really benefit from any kind of optimization.

Transform it into a "normal" function by moving it to

  drivers/net/can/dev/dev.c

Signed-off-by: Vincent Mailhol <mailhol@kernel.org>
---
This also serves as a preparation for the next patch in which we are
adding can_set_default_mtu(). That function will only be used by the
can_dev.ko module and so we do not need to export its GPL
symbol. However, if can_set_static_ctrlmode() stays as a static
inline, then the call to set_default_mtu(), which we plan to add in
can_set_static_ctrlmode(), would also be inlined and thus would become
visible to the users of can_set_static_ctrlmode().

Making can_set_static_ctrlmode() a non-inline function resolve this
dependency.
---
 drivers/net/can/dev/dev.c | 21 +++++++++++++++++++++
 include/linux/can/dev.h   | 23 ++---------------------
 2 files changed, 23 insertions(+), 21 deletions(-)

diff --git a/drivers/net/can/dev/dev.c b/drivers/net/can/dev/dev.c
index 3913971125de0ab16b4ad9f36712954141014ddf..a0ae659beedcd1fa0979662c12614ae7846032c0 100644
--- a/drivers/net/can/dev/dev.c
+++ b/drivers/net/can/dev/dev.c
@@ -347,6 +347,27 @@ int can_change_mtu(struct net_device *dev, int new_mtu)
 }
 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)
+{
+	struct can_priv *priv = netdev_priv(dev);
+
+	/* alloc_candev() succeeded => netdev_priv() is valid at this point */
+	if (priv->ctrlmode_supported & static_mode) {
+		netdev_warn(dev,
+			    "Controller features can not be supported and static at the same time\n");
+		return -EINVAL;
+	}
+	priv->ctrlmode = static_mode;
+
+	/* override MTU which was set by default in can_setup()? */
+	if (static_mode & CAN_CTRLMODE_FD)
+		dev->mtu = CANFD_MTU;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(can_set_static_ctrlmode);
+
 /* generic implementation of netdev_ops::ndo_eth_ioctl for CAN devices
  * supporting hardware timestamps
  */
diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h
index 9a92cbe5b2cb7ccdfca3121718856d096e9ecfa6..5dc58360c2d74a1711d4e02d28fe52ae20b146e0 100644
--- a/include/linux/can/dev.h
+++ b/include/linux/can/dev.h
@@ -125,27 +125,6 @@ static inline s32 can_get_relative_tdco(const struct can_priv *priv)
 	return (s32)priv->fd.tdc.tdco - sample_point_in_tc;
 }
 
-/* helper to define static CAN controller features at device creation time */
-static inline int __must_check can_set_static_ctrlmode(struct net_device *dev,
-						       u32 static_mode)
-{
-	struct can_priv *priv = netdev_priv(dev);
-
-	/* alloc_candev() succeeded => netdev_priv() is valid at this point */
-	if (priv->ctrlmode_supported & static_mode) {
-		netdev_warn(dev,
-			    "Controller features can not be supported and static at the same time\n");
-		return -EINVAL;
-	}
-	priv->ctrlmode = static_mode;
-
-	/* override MTU which was set by default in can_setup()? */
-	if (static_mode & CAN_CTRLMODE_FD)
-		dev->mtu = CANFD_MTU;
-
-	return 0;
-}
-
 static inline u32 can_get_static_ctrlmode(struct can_priv *priv)
 {
 	return priv->ctrlmode & ~priv->ctrlmode_supported;
@@ -188,6 +167,8 @@ struct can_priv *safe_candev_priv(struct net_device *dev);
 int open_candev(struct net_device *dev);
 void close_candev(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);
 int can_ethtool_op_get_ts_info_hwts(struct net_device *dev,
 				    struct kernel_ethtool_ts_info *info);

-- 
2.49.1

[PATCH RFC 3/5] can: populate the minimum and maximum MTU values

[Vincent Mailhol]

By populating:

  net_device->min_mtu

and

  net_device->max_mtu

the net core infrastructure will automatically:

  1. validate that the user's inputs are in range.

  2. report those min and max MTU values through the netlink
     interface.

Add can_set_default_mtu() which will set the default mtu value as well
as the minimum and maximum values. The logic for the default mtu value
remains unchanged:

  - CANFD_MTU if the device has a static CAN_CTRLMODE_FD.

  - CAN_MTU otherwise.

Call can_set_default_mtu() each time the CAN_CTRLMODE_FD is modified.
This will guarantee that the MTU value is always consistent with the
control mode flags.

With this, the checks done in can_change_mtu() become fully redundant
and will be removed in an upcoming change and it is now possible to
confirm the minimum and maximum MTU values on a physical CAN interface
by doing:

  $ ip --details link show can0

The virtual interfaces (vcan and vxcan) are not impacted by this
change.

Signed-off-by: Vincent Mailhol <mailhol@kernel.org>
---
With this, when adding the CAN XL netlink interface, all we have to do
is to add one if branch to can_set_default_mtu() like this:

	void can_set_default_mtu(struct net_device *dev)
	{
		struct can_priv *priv = netdev_priv(dev);

		if (priv->ctrlmode & CAN_CTRLMODE_XL) {
			dev->mtu = CANXL_MTU;
			dev->min_mtu = CANXL_MIN_MTU;
			dev->max_mtu = CANXL_MAX_MTU;
		} else if (priv->ctrlmode & CAN_CTRLMODE_FD) {
			dev->mtu = CANFD_MTU;
			dev->min_mtu = CANFD_MTU;
			dev->max_mtu = CANFD_MTU;
		} else {
			dev->mtu = CAN_MTU;
			dev->min_mtu = CAN_MTU;
			dev->max_mtu = CAN_MTU;
		}
	}

and we will be done!
---
 drivers/net/can/dev/dev.c     | 21 ++++++++++++++++++---
 drivers/net/can/dev/netlink.c |  9 ++++-----
 include/linux/can/dev.h       |  1 +
 3 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/drivers/net/can/dev/dev.c b/drivers/net/can/dev/dev.c
index a0ae659beedcd1fa0979662c12614ae7846032c0..69c00720e9956cad986ea86fbba49285d76f51db 100644
--- a/drivers/net/can/dev/dev.c
+++ b/drivers/net/can/dev/dev.c
@@ -239,11 +239,12 @@ EXPORT_SYMBOL_GPL(can_bus_off);
 void can_setup(struct net_device *dev)
 {
 	dev->type = ARPHRD_CAN;
-	dev->mtu = CAN_MTU;
 	dev->hard_header_len = 0;
 	dev->addr_len = 0;
 	dev->tx_queue_len = 10;
 
+	can_set_default_mtu(dev);
+
 	/* New-style flags. */
 	dev->flags = IFF_NOARP;
 	dev->features = NETIF_F_HW_CSUM;
@@ -309,6 +310,21 @@ void free_candev(struct net_device *dev)
 }
 EXPORT_SYMBOL_GPL(free_candev);
 
+void can_set_default_mtu(struct net_device *dev)
+{
+	struct can_priv *priv = netdev_priv(dev);
+
+	if (priv->ctrlmode & CAN_CTRLMODE_FD) {
+		dev->mtu = CANFD_MTU;
+		dev->min_mtu = CANFD_MTU;
+		dev->max_mtu = CANFD_MTU;
+	} else {
+		dev->mtu = CAN_MTU;
+		dev->min_mtu = CAN_MTU;
+		dev->max_mtu = CAN_MTU;
+	}
+}
+
 /* changing MTU and control mode for CAN/CANFD devices */
 int can_change_mtu(struct net_device *dev, int new_mtu)
 {
@@ -361,8 +377,7 @@ int can_set_static_ctrlmode(struct net_device *dev, u32 static_mode)
 	priv->ctrlmode = static_mode;
 
 	/* override MTU which was set by default in can_setup()? */
-	if (static_mode & CAN_CTRLMODE_FD)
-		dev->mtu = CANFD_MTU;
+	can_set_default_mtu(dev);
 
 	return 0;
 }
diff --git a/drivers/net/can/dev/netlink.c b/drivers/net/can/dev/netlink.c
index d9f6ab3efb9767409c318b714f19df8a30e51137..248f607e3864ffbda6f0b8daf4e2484179cf9cd5 100644
--- a/drivers/net/can/dev/netlink.c
+++ b/drivers/net/can/dev/netlink.c
@@ -223,17 +223,16 @@ static int can_changelink(struct net_device *dev, struct nlattr *tb[],
 		priv->ctrlmode &= ~cm->mask;
 		priv->ctrlmode |= maskedflags;
 
-		/* CAN_CTRLMODE_FD can only be set when driver supports FD */
-		if (priv->ctrlmode & CAN_CTRLMODE_FD) {
-			dev->mtu = CANFD_MTU;
-		} else {
-			dev->mtu = CAN_MTU;
+		/* Wipe potential leftovers from previous CAN FD config */
+		if (!(priv->ctrlmode & CAN_CTRLMODE_FD)) {
 			memset(&priv->fd.data_bittiming, 0,
 			       sizeof(priv->fd.data_bittiming));
 			priv->ctrlmode &= ~CAN_CTRLMODE_FD_TDC_MASK;
 			memset(&priv->fd.tdc, 0, sizeof(priv->fd.tdc));
 		}
 
+		can_set_default_mtu(dev);
+
 		fd_tdc_flag_provided = cm->mask & CAN_CTRLMODE_FD_TDC_MASK;
 		/* CAN_CTRLMODE_TDC_{AUTO,MANUAL} are mutually
 		 * exclusive: make sure to turn the other one off
diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h
index 5dc58360c2d74a1711d4e02d28fe52ae20b146e0..3354f70ed2c684d7d482549560d4cb5838cbebd5 100644
--- a/include/linux/can/dev.h
+++ b/include/linux/can/dev.h
@@ -166,6 +166,7 @@ struct can_priv *safe_candev_priv(struct net_device *dev);
 
 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);

-- 
2.49.1

[PATCH RFC 4/5] can: treewide: remove can_change_mtu()

[Vincent Mailhol]

can_change_mtu() became obsolete by the previous patch. 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 can_change_mtu() and remove the
net_device_ops->ndo_change_mtu() callback of all the physical
interfaces. Only keep the vcan_change_mtu() and vxcan_change_mtu()
because the virtual interfaces use their own different logic.

Signed-off-by: Vincent Mailhol <mailhol@kernel.org>
---
 drivers/net/can/at91_can.c                         |  1 -
 drivers/net/can/bxcan.c                            |  1 -
 drivers/net/can/c_can/c_can_main.c                 |  1 -
 drivers/net/can/can327.c                           |  1 -
 drivers/net/can/cc770/cc770.c                      |  1 -
 drivers/net/can/ctucanfd/ctucanfd_base.c           |  1 -
 drivers/net/can/dev/dev.c                          | 38 ----------------------
 drivers/net/can/esd/esd_402_pci-core.c             |  1 -
 drivers/net/can/flexcan/flexcan-core.c             |  1 -
 drivers/net/can/grcan.c                            |  1 -
 drivers/net/can/ifi_canfd/ifi_canfd.c              |  1 -
 drivers/net/can/janz-ican3.c                       |  1 -
 drivers/net/can/kvaser_pciefd/kvaser_pciefd_core.c |  1 -
 drivers/net/can/m_can/m_can.c                      |  1 -
 drivers/net/can/mscan/mscan.c                      |  1 -
 drivers/net/can/peak_canfd/peak_canfd.c            |  1 -
 drivers/net/can/rcar/rcar_can.c                    |  1 -
 drivers/net/can/rcar/rcar_canfd.c                  |  1 -
 drivers/net/can/rockchip/rockchip_canfd-core.c     |  1 -
 drivers/net/can/sja1000/sja1000.c                  |  1 -
 drivers/net/can/slcan/slcan-core.c                 |  1 -
 drivers/net/can/softing/softing_main.c             |  1 -
 drivers/net/can/spi/hi311x.c                       |  1 -
 drivers/net/can/spi/mcp251x.c                      |  1 -
 drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c     |  1 -
 drivers/net/can/sun4i_can.c                        |  1 -
 drivers/net/can/ti_hecc.c                          |  1 -
 drivers/net/can/usb/ems_usb.c                      |  1 -
 drivers/net/can/usb/esd_usb.c                      |  1 -
 drivers/net/can/usb/etas_es58x/es58x_core.c        |  1 -
 drivers/net/can/usb/f81604.c                       |  1 -
 drivers/net/can/usb/gs_usb.c                       |  1 -
 drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c   |  1 -
 drivers/net/can/usb/mcba_usb.c                     |  1 -
 drivers/net/can/usb/peak_usb/pcan_usb_core.c       |  1 -
 drivers/net/can/usb/ucan.c                         |  1 -
 drivers/net/can/usb/usb_8dev.c                     |  1 -
 drivers/net/can/xilinx_can.c                       |  1 -
 include/linux/can/dev.h                            |  1 -
 39 files changed, 76 deletions(-)

diff --git a/drivers/net/can/at91_can.c b/drivers/net/can/at91_can.c
index 191707d7e3dac2b816575b9232178a171559a494..c2a3a4eef5b281f6723e3fa7a40bba1a1d623a54 100644
--- a/drivers/net/can/at91_can.c
+++ b/drivers/net/can/at91_can.c
@@ -948,7 +948,6 @@ static const struct net_device_ops at91_netdev_ops = {
 	.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 = {
diff --git a/drivers/net/can/bxcan.c b/drivers/net/can/bxcan.c
index bfc60eb33dc3752722909c3cf6bffad29696f851..9c3af7049814385501bfd950c35c90ccfc42a2e8 100644
--- a/drivers/net/can/bxcan.c
+++ b/drivers/net/can/bxcan.c
@@ -881,7 +881,6 @@ static const struct net_device_ops bxcan_netdev_ops = {
 	.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 = {
diff --git a/drivers/net/can/c_can/c_can_main.c b/drivers/net/can/c_can/c_can_main.c
index cc371d0c9f3c769051ff1e0a8954d8c52dbcdbf6..3702cac7fbf0f08a509cf65f388c8707ed196fef 100644
--- a/drivers/net/can/c_can/c_can_main.c
+++ b/drivers/net/can/c_can/c_can_main.c
@@ -1362,7 +1362,6 @@ static const struct net_device_ops c_can_netdev_ops = {
 	.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)
diff --git a/drivers/net/can/can327.c b/drivers/net/can/can327.c
index 24af639610309dd2a3372151782b8c9a32306306..b66fc16aedd2cc23f65ef3bf3d7f9e1a7c24d395 100644
--- a/drivers/net/can/can327.c
+++ b/drivers/net/can/can327.c
@@ -849,7 +849,6 @@ static const struct net_device_ops can327_netdev_ops = {
 	.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 = {
diff --git a/drivers/net/can/cc770/cc770.c b/drivers/net/can/cc770/cc770.c
index 30909f3aab576fb8eefb46b83f0aeca2fa7ffda1..8d5abd643c068e9f4d5a1eba8f3b0ce6a21c9de8 100644
--- a/drivers/net/can/cc770/cc770.c
+++ b/drivers/net/can/cc770/cc770.c
@@ -834,7 +834,6 @@ static const struct net_device_ops cc770_netdev_ops = {
 	.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 = {
diff --git a/drivers/net/can/ctucanfd/ctucanfd_base.c b/drivers/net/can/ctucanfd/ctucanfd_base.c
index 8bd3f0fc385c3096e21aca20244e4ce04cf5708c..1e6b9e3dc2fea42801291cea75d55c268b0f3a41 100644
--- a/drivers/net/can/ctucanfd/ctucanfd_base.c
+++ b/drivers/net/can/ctucanfd/ctucanfd_base.c
@@ -1301,7 +1301,6 @@ static const struct net_device_ops ctucan_netdev_ops = {
 	.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 = {
diff --git a/drivers/net/can/dev/dev.c b/drivers/net/can/dev/dev.c
index 69c00720e9956cad986ea86fbba49285d76f51db..dcee4af436f4de837344fdf7965f7aa99f52df14 100644
--- a/drivers/net/can/dev/dev.c
+++ b/drivers/net/can/dev/dev.c
@@ -325,44 +325,6 @@ void can_set_default_mtu(struct net_device *dev)
 	}
 }
 
-/* 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)
 {
diff --git a/drivers/net/can/esd/esd_402_pci-core.c b/drivers/net/can/esd/esd_402_pci-core.c
index 5d6d2828cd0458bc87c9e5fbab1fd0c41a970cdd..05adecae63757b80b2b419e5831d0d7a671ae545 100644
--- a/drivers/net/can/esd/esd_402_pci-core.c
+++ b/drivers/net/can/esd/esd_402_pci-core.c
@@ -86,7 +86,6 @@ static const struct net_device_ops pci402_acc_netdev_ops = {
 	.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,
 };
 
diff --git a/drivers/net/can/flexcan/flexcan-core.c b/drivers/net/can/flexcan/flexcan-core.c
index 06d5d35fc1b550d51dd92211340e9d71aa7f002c..f5d22c61503faa4fc20415aeaca22b6f25b8aa83 100644
--- a/drivers/net/can/flexcan/flexcan-core.c
+++ b/drivers/net/can/flexcan/flexcan-core.c
@@ -1867,7 +1867,6 @@ static const struct net_device_ops flexcan_netdev_ops = {
 	.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)
diff --git a/drivers/net/can/grcan.c b/drivers/net/can/grcan.c
index c5784d9779ef518ac253e66923ef542d52584373..3b1b09943436fab13024f88f7bf2cc67b1e11926 100644
--- a/drivers/net/can/grcan.c
+++ b/drivers/net/can/grcan.c
@@ -1561,7 +1561,6 @@ static const struct net_device_ops grcan_netdev_ops = {
 	.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 = {
diff --git a/drivers/net/can/ifi_canfd/ifi_canfd.c b/drivers/net/can/ifi_canfd/ifi_canfd.c
index 2eeee65f606f37d8f1c1f1b8002daf8a12c93248..0f83335e4d075ed4c2a178efb4ea097f3c846d2a 100644
--- a/drivers/net/can/ifi_canfd/ifi_canfd.c
+++ b/drivers/net/can/ifi_canfd/ifi_canfd.c
@@ -944,7 +944,6 @@ static const struct net_device_ops ifi_canfd_netdev_ops = {
 	.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 = {
diff --git a/drivers/net/can/janz-ican3.c b/drivers/net/can/janz-ican3.c
index bfa5cbe88017d42a61caa20d22e25084f1a9656a..1efdd1fd8caa424bf4d42ed3985f4b39e1c118da 100644
--- a/drivers/net/can/janz-ican3.c
+++ b/drivers/net/can/janz-ican3.c
@@ -1752,7 +1752,6 @@ static const struct net_device_ops ican3_netdev_ops = {
 	.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 = {
diff --git a/drivers/net/can/kvaser_pciefd/kvaser_pciefd_core.c b/drivers/net/can/kvaser_pciefd/kvaser_pciefd_core.c
index 0880023611bebeef671ad1d9b9921d30b8193dd2..705f9bb74cd23c9c6a5f34fd7c0f7a529d0535d0 100644
--- a/drivers/net/can/kvaser_pciefd/kvaser_pciefd_core.c
+++ b/drivers/net/can/kvaser_pciefd/kvaser_pciefd_core.c
@@ -904,7 +904,6 @@ static const struct net_device_ops kvaser_pciefd_netdev_ops = {
 	.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,
diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index fe74dbd2c9663b7090678ab78318698d50ffb481..0e043aee045b40f11559f5a7728dad440dc3e85a 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -2129,7 +2129,6 @@ static const struct net_device_ops m_can_netdev_ops = {
 	.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,
diff --git a/drivers/net/can/mscan/mscan.c b/drivers/net/can/mscan/mscan.c
index 8c2a7bc64d3d714d33445ebbff5fa41218d68b1f..39c7aa2a0b2f8e1d61745136ee694dd5e50724fd 100644
--- a/drivers/net/can/mscan/mscan.c
+++ b/drivers/net/can/mscan/mscan.c
@@ -607,7 +607,6 @@ static const struct net_device_ops mscan_netdev_ops = {
 	.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 = {
diff --git a/drivers/net/can/peak_canfd/peak_canfd.c b/drivers/net/can/peak_canfd/peak_canfd.c
index 77292afaed227878fb9fb4b86199b28892bbc5ca..8cb642011235168d04028183dab67205630d2621 100644
--- a/drivers/net/can/peak_canfd/peak_canfd.c
+++ b/drivers/net/can/peak_canfd/peak_canfd.c
@@ -773,7 +773,6 @@ static const struct net_device_ops peak_canfd_netdev_ops = {
 	.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,
diff --git a/drivers/net/can/rcar/rcar_can.c b/drivers/net/can/rcar/rcar_can.c
index 87c134bcd48db559db45c901a12c40cef00dcde4..f157529a4934d6394abaed292e88816e21e8d439 100644
--- a/drivers/net/can/rcar/rcar_can.c
+++ b/drivers/net/can/rcar/rcar_can.c
@@ -628,7 +628,6 @@ static const struct net_device_ops rcar_can_netdev_ops = {
 	.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 = {
diff --git a/drivers/net/can/rcar/rcar_canfd.c b/drivers/net/can/rcar/rcar_canfd.c
index b3c8c592fb0e04edfef30989c3df659ad772a80f..bc0ddf31d21dd2b33726c34f7acb49e11c2a904a 100644
--- a/drivers/net/can/rcar/rcar_canfd.c
+++ b/drivers/net/can/rcar/rcar_canfd.c
@@ -1810,7 +1810,6 @@ static const struct net_device_ops rcar_canfd_netdev_ops = {
 	.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 = {
diff --git a/drivers/net/can/rockchip/rockchip_canfd-core.c b/drivers/net/can/rockchip/rockchip_canfd-core.c
index 046f0a0ae4d4b06a076f9a72b9ad6603fa0ac31e..29de0c01e4edcf1a725a27dd47b5b61c0807b0be 100644
--- a/drivers/net/can/rockchip/rockchip_canfd-core.c
+++ b/drivers/net/can/rockchip/rockchip_canfd-core.c
@@ -761,7 +761,6 @@ static const struct net_device_ops rkcanfd_netdev_ops = {
 	.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)
diff --git a/drivers/net/can/sja1000/sja1000.c b/drivers/net/can/sja1000/sja1000.c
index 4d245857ef1cec0ae1ee82008b96912bbb1f2638..acfa49db3907ed2eeed748e0661c45a8e167c756 100644
--- a/drivers/net/can/sja1000/sja1000.c
+++ b/drivers/net/can/sja1000/sja1000.c
@@ -697,7 +697,6 @@ static const struct net_device_ops sja1000_netdev_ops = {
 	.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 = {
diff --git a/drivers/net/can/slcan/slcan-core.c b/drivers/net/can/slcan/slcan-core.c
index 58ff2ec1d9757e0ce55ce73b85e1884937a73d72..cd789e178d34bbbf3297f59823b90a0e1612ba37 100644
--- a/drivers/net/can/slcan/slcan-core.c
+++ b/drivers/net/can/slcan/slcan-core.c
@@ -774,7 +774,6 @@ static const struct net_device_ops slcan_netdev_ops = {
 	.ndo_open               = slcan_netdev_open,
 	.ndo_stop               = slcan_netdev_close,
 	.ndo_start_xmit         = slcan_netdev_xmit,
-	.ndo_change_mtu         = can_change_mtu,
 };
 
 /******************************************
diff --git a/drivers/net/can/softing/softing_main.c b/drivers/net/can/softing/softing_main.c
index 278ee8722770c252a2df20c7f3cd61a895a31b59..79bc64395ac4608fd1a1f9f4deac7b1f4b9a497b 100644
--- a/drivers/net/can/softing/softing_main.c
+++ b/drivers/net/can/softing/softing_main.c
@@ -609,7 +609,6 @@ static const struct net_device_ops softing_netdev_ops = {
 	.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 = {
diff --git a/drivers/net/can/spi/hi311x.c b/drivers/net/can/spi/hi311x.c
index 6441ff3b4198718e8e662daa3022f06a2405f322..09ae218315d73d49c2ec4280707911966fce1c31 100644
--- a/drivers/net/can/spi/hi311x.c
+++ b/drivers/net/can/spi/hi311x.c
@@ -812,7 +812,6 @@ static const struct net_device_ops hi3110_netdev_ops = {
 	.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 = {
diff --git a/drivers/net/can/spi/mcp251x.c b/drivers/net/can/spi/mcp251x.c
index 313e1d241f0110ccee900c3f17e479ff1a4a1919..1075c9015f6b2c83c2cdc1c5c565879b50433020 100644
--- a/drivers/net/can/spi/mcp251x.c
+++ b/drivers/net/can/spi/mcp251x.c
@@ -1270,7 +1270,6 @@ static const struct net_device_ops mcp251x_netdev_ops = {
 	.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 = {
diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
index 7450ea42c1ea51a908d1e016aacbf67c4e71c57f..9402530ba3d48beaa59ccefb929a4fd35290bd01 100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
@@ -1715,7 +1715,6 @@ static const struct net_device_ops mcp251xfd_netdev_ops = {
 	.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
diff --git a/drivers/net/can/sun4i_can.c b/drivers/net/can/sun4i_can.c
index 53bfd873de9bdecaf6923049007f9efd71289dd3..6fcb301ef611d0c8bdb8720aaa77dc78950123d6 100644
--- a/drivers/net/can/sun4i_can.c
+++ b/drivers/net/can/sun4i_can.c
@@ -768,7 +768,6 @@ static const struct net_device_ops sun4ican_netdev_ops = {
 	.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 = {
diff --git a/drivers/net/can/ti_hecc.c b/drivers/net/can/ti_hecc.c
index e6d6661a908ab12eb4c7ec61c162848c18ef20f4..1d3dbf28b1057c50effc43c488e472bbc71de9ca 100644
--- a/drivers/net/can/ti_hecc.c
+++ b/drivers/net/can/ti_hecc.c
@@ -829,7 +829,6 @@ static const struct net_device_ops ti_hecc_netdev_ops = {
 	.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 = {
diff --git a/drivers/net/can/usb/ems_usb.c b/drivers/net/can/usb/ems_usb.c
index 5355bac4dccbe0e31ba115909b0537a9b92c2fa6..de8e212a1366b4367e9abb6ae702769e399b45bc 100644
--- a/drivers/net/can/usb/ems_usb.c
+++ b/drivers/net/can/usb/ems_usb.c
@@ -885,7 +885,6 @@ static const struct net_device_ops ems_usb_netdev_ops = {
 	.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 = {
diff --git a/drivers/net/can/usb/esd_usb.c b/drivers/net/can/usb/esd_usb.c
index 27a3818885c2ca7451e9ce959b06e6e15e70a4a6..a9418341dbf61630bd90dbf76689170f775bad9a 100644
--- a/drivers/net/can/usb/esd_usb.c
+++ b/drivers/net/can/usb/esd_usb.c
@@ -991,7 +991,6 @@ static const struct net_device_ops esd_usb_netdev_ops = {
 	.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 = {
diff --git a/drivers/net/can/usb/etas_es58x/es58x_core.c b/drivers/net/can/usb/etas_es58x/es58x_core.c
index adc91873c083f968ff7571a5b0db5747988482c5..47d9e03f304495db90e7d69bd135aaaa4a8d01ed 100644
--- a/drivers/net/can/usb/etas_es58x/es58x_core.c
+++ b/drivers/net/can/usb/etas_es58x/es58x_core.c
@@ -1977,7 +1977,6 @@ static const struct net_device_ops es58x_netdev_ops = {
 	.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 = {
diff --git a/drivers/net/can/usb/f81604.c b/drivers/net/can/usb/f81604.c
index e0cfa1460b0b83110d5ce7ffe07bac442ce8a682..efe61ece79ea251056fd44d208de145e24eedf16 100644
--- a/drivers/net/can/usb/f81604.c
+++ b/drivers/net/can/usb/f81604.c
@@ -1052,7 +1052,6 @@ static const struct net_device_ops f81604_netdev_ops = {
 	.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 = {
diff --git a/drivers/net/can/usb/gs_usb.c b/drivers/net/can/usb/gs_usb.c
index c9482d6e947b0c7b033dc4f0c35f5b111e1bfd92..aea35aa15a7cd667df04e047b42cc949d8b27fbb 100644
--- a/drivers/net/can/usb/gs_usb.c
+++ b/drivers/net/can/usb/gs_usb.c
@@ -1105,7 +1105,6 @@ static const struct net_device_ops gs_usb_netdev_ops = {
 	.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,
 };
 
diff --git a/drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c b/drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c
index 90e77fa0ff4a58b25eec33e0f9ffcb54dab97438..89e22b66f91929ac1785b18289cb7669cfa2aaef 100644
--- a/drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c
+++ b/drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c
@@ -786,7 +786,6 @@ static const struct net_device_ops kvaser_usb_netdev_ops = {
 	.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 = {
diff --git a/drivers/net/can/usb/mcba_usb.c b/drivers/net/can/usb/mcba_usb.c
index 1f9b915094e64de875adff35026e9cd3beb0410d..41c0a1c399bf36104fbf8991b537acdb01e7e950 100644
--- a/drivers/net/can/usb/mcba_usb.c
+++ b/drivers/net/can/usb/mcba_usb.c
@@ -761,7 +761,6 @@ static const struct net_device_ops mcba_netdev_ops = {
 	.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 = {
diff --git a/drivers/net/can/usb/peak_usb/pcan_usb_core.c b/drivers/net/can/usb/peak_usb/pcan_usb_core.c
index 117637b9b995b9e7aa8f313574cf9e0a9929e93d..7903de379de36f862209f2ee9a19e26e0026c336 100644
--- a/drivers/net/can/usb/peak_usb/pcan_usb_core.c
+++ b/drivers/net/can/usb/peak_usb/pcan_usb_core.c
@@ -814,7 +814,6 @@ static const struct net_device_ops peak_usb_netdev_ops = {
 	.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.
diff --git a/drivers/net/can/usb/ucan.c b/drivers/net/can/usb/ucan.c
index 07406daf7c88ed64edbe501a87b259b77053be93..de61d9da99e359c3d3b0293302a72c96aabc1bb2 100644
--- a/drivers/net/can/usb/ucan.c
+++ b/drivers/net/can/usb/ucan.c
@@ -1233,7 +1233,6 @@ static const struct net_device_ops ucan_netdev_ops = {
 	.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 = {
diff --git a/drivers/net/can/usb/usb_8dev.c b/drivers/net/can/usb/usb_8dev.c
index 8a5596ce4e46312e6080a424e0107e0c22595267..7449328f7cd7279bc259eb746131586f70bb1c0f 100644
--- a/drivers/net/can/usb/usb_8dev.c
+++ b/drivers/net/can/usb/usb_8dev.c
@@ -868,7 +868,6 @@ static const struct net_device_ops usb_8dev_netdev_ops = {
 	.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 = {
diff --git a/drivers/net/can/xilinx_can.c b/drivers/net/can/xilinx_can.c
index a25a3ca62c12e3a0a5674581c3787595e543d843..43d7f22820b88efcdba2ed5f0918c724b3bdd973 100644
--- a/drivers/net/can/xilinx_can.c
+++ b/drivers/net/can/xilinx_can.c
@@ -1702,7 +1702,6 @@ static const struct net_device_ops xcan_netdev_ops = {
 	.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 = {
diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h
index 3354f70ed2c684d7d482549560d4cb5838cbebd5..48a6851b047fd339a87e96cadda8d5e39b2e8c73 100644
--- a/include/linux/can/dev.h
+++ b/include/linux/can/dev.h
@@ -167,7 +167,6 @@ struct can_priv *safe_candev_priv(struct net_device *dev);
 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);

-- 
2.49.1

[PATCH RFC 5/5] can: enable CAN XL for virtual CAN devices by default

[Vincent Mailhol]

In commit 97edec3a11cf ("can: enable CAN FD for virtual CAN devices by
default"), vcan and vxcan default MTU was set to CANFD_MTU by default.
The reason was that users were confused on how to activate CAN FD on
virtual interfaces.

Following the introduction of CAN XL, the same logic should be
applied. Set the MTU to CANXL_MTU by default.

The users who really wish to use a Classical CAN only or a CAN FD
virtual device can do respectively:

  $ ip link set vcan0 mtu 16

or

  $ ip link set vcan0 mtu 72

to force the old behaviour.

Signed-off-by: Vincent Mailhol <mailhol@kernel.org>
---
 drivers/net/can/vcan.c  | 2 +-
 drivers/net/can/vxcan.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/can/vcan.c b/drivers/net/can/vcan.c
index f67e858071007acd5f34fa00a76212f1a77997a6..fdc662aea2798125b3aa373f09958363b427ced2 100644
--- a/drivers/net/can/vcan.c
+++ b/drivers/net/can/vcan.c
@@ -156,7 +156,7 @@ static const struct ethtool_ops vcan_ethtool_ops = {
 static void vcan_setup(struct net_device *dev)
 {
 	dev->type		= ARPHRD_CAN;
-	dev->mtu		= CANFD_MTU;
+	dev->mtu		= CANXL_MTU;
 	dev->hard_header_len	= 0;
 	dev->addr_len		= 0;
 	dev->tx_queue_len	= 0;
diff --git a/drivers/net/can/vxcan.c b/drivers/net/can/vxcan.c
index 99a78a75716749bf858cc78eadb41ca2588fcf94..b2c19f8c5f8e5101b8be343401afe9a4f388c4da 100644
--- a/drivers/net/can/vxcan.c
+++ b/drivers/net/can/vxcan.c
@@ -156,7 +156,7 @@ static void vxcan_setup(struct net_device *dev)
 	struct can_ml_priv *can_ml;
 
 	dev->type		= ARPHRD_CAN;
-	dev->mtu		= CANFD_MTU;
+	dev->mtu		= CANXL_MTU;
 	dev->hard_header_len	= 0;
 	dev->addr_len		= 0;
 	dev->tx_queue_len	= 0;

-- 
2.49.1