linux-toradex.git/drivers/net/can/vcan.c, branch v5.17-rc4 Linux kernel for Apalis and Colibri modules can: do not increase tx_bytes statistics for RTR frames 2022-01-05T11:09:05+00:00 Vincent Mailhol mailhol.vincent@wanadoo.fr 2021-12-07T12:15:31+00:00 cc4b08c31b5c51352f258032cc65e884b3e61e6a The actual payload length of the CAN Remote Transmission Request (RTR) frames is always 0, i.e. no payload is transmitted on the wire. However, those RTR frames still use the DLC to indicate the length of the requested frame. As such, net_device_stats::tx_bytes should not be increased when sending RTR frames. The function can_get_echo_skb() already returns the correct length, even for RTR frames (c.f. [1]). However, for historical reasons, the drivers do not use can_get_echo_skb()'s return value and instead, most of them store a temporary length (or dlc) in some local structure or array. Using the return value of can_get_echo_skb() solves the issue. After doing this, such length/dlc fields become unused and so this patch does the adequate cleaning when needed. This patch fixes all the CAN drivers. Finally, can_get_echo_skb() is decorated with the __must_check attribute in order to force future drivers to correctly use its return value (else the compiler would emit a warning). [1] commit ed3320cec279 ("can: dev: __can_get_echo_skb(): fix real payload length return value for RTR frames") Link: https://lore.kernel.org/all/20211207121531.42941-6-mailhol.vincent@wanadoo.fr Cc: Nicolas Ferre <nicolas.ferre@microchip.com> Cc: Alexandre Belloni <alexandre.belloni@bootlin.com> Cc: Ludovic Desroches <ludovic.desroches@microchip.com> Cc: Maxime Ripard <mripard@kernel.org> Cc: Chen-Yu Tsai <wens@csie.org> Cc: Jernej Skrabec <jernej.skrabec@gmail.com> Cc: Yasushi SHOJI <yashi@spacecubics.com> Cc: Oliver Hartkopp <socketcan@hartkopp.net> Cc: Stephane Grosjean <s.grosjean@peak-system.com> Cc: Andreas Larsson <andreas@gaisler.com> Tested-by: Jimmy Assarsson <extja@kvaser.com> # kvaser Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr> Acked-by: Stefan Mätje <stefan.maetje@esd.eu> # esd_usb2 Tested-by: Stefan Mätje <stefan.maetje@esd.eu> # esd_usb2 [mkl: add conversion for grcan] Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> 
The actual payload length of the CAN Remote Transmission Request (RTR)
frames is always 0, i.e. no payload is transmitted on the wire.
However, those RTR frames still use the DLC to indicate the length of
the requested frame.

As such, net_device_stats::tx_bytes should not be increased when
sending RTR frames.

The function can_get_echo_skb() already returns the correct length,
even for RTR frames (c.f. [1]). However, for historical reasons, the
drivers do not use can_get_echo_skb()'s return value and instead, most
of them store a temporary length (or dlc) in some local structure or
array. Using the return value of can_get_echo_skb() solves the
issue. After doing this, such length/dlc fields become unused and so
this patch does the adequate cleaning when needed.

This patch fixes all the CAN drivers.

Finally, can_get_echo_skb() is decorated with the __must_check
attribute in order to force future drivers to correctly use its return
value (else the compiler would emit a warning).

[1] commit ed3320cec279 ("can: dev: __can_get_echo_skb():
fix real payload length return value for RTR frames")

Link: https://lore.kernel.org/all/20211207121531.42941-6-mailhol.vincent@wanadoo.fr
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Ludovic Desroches <ludovic.desroches@microchip.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Chen-Yu Tsai <wens@csie.org>
Cc: Jernej Skrabec <jernej.skrabec@gmail.com>
Cc: Yasushi SHOJI <yashi@spacecubics.com>
Cc: Oliver Hartkopp <socketcan@hartkopp.net>
Cc: Stephane Grosjean <s.grosjean@peak-system.com>
Cc: Andreas Larsson <andreas@gaisler.com>
Tested-by: Jimmy Assarsson <extja@kvaser.com> # kvaser
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Acked-by: Stefan Mätje <stefan.maetje@esd.eu> # esd_usb2
Tested-by: Stefan Mätje <stefan.maetje@esd.eu> # esd_usb2
[mkl: add conversion for grcan]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
net: introduce CAN specific pointer in the struct net_device 2021-02-24T22:32:15+00:00 Oleksij Rempel o.rempel@pengutronix.de 2021-02-23T07:01:26+00:00 4e096a18867a5a989b510f6999d9c6b6622e8f7b Since 20dd3850bcf8 ("can: Speed up CAN frame receiption by using ml_priv") the CAN framework uses per device specific data in the AF_CAN protocol. For this purpose the struct net_device->ml_priv is used. Later the ml_priv usage in CAN was extended for other users, one of them being CAN_J1939. Later in the kernel ml_priv was converted to an union, used by other drivers. E.g. the tun driver started storing it's stats pointer. Since tun devices can claim to be a CAN device, CAN specific protocols will wrongly interpret this pointer, which will cause system crashes. Mostly this issue is visible in the CAN_J1939 stack. To fix this issue, we request a dedicated CAN pointer within the net_device struct. Reported-by: syzbot+5138c4dd15a0401bec7b@syzkaller.appspotmail.com Fixes: 20dd3850bcf8 ("can: Speed up CAN frame receiption by using ml_priv") Fixes: ffd956eef69b ("can: introduce CAN midlayer private and allocate it automatically") Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol") Fixes: 497a5757ce4e ("tun: switch to net core provided statistics counters") Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> Link: https://lore.kernel.org/r/20210223070127.4538-1-o.rempel@pengutronix.de Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Since 20dd3850bcf8 ("can: Speed up CAN frame receiption by using
ml_priv") the CAN framework uses per device specific data in the AF_CAN
protocol. For this purpose the struct net_device->ml_priv is used. Later
the ml_priv usage in CAN was extended for other users, one of them being
CAN_J1939.

Later in the kernel ml_priv was converted to an union, used by other
drivers. E.g. the tun driver started storing it's stats pointer.

Since tun devices can claim to be a CAN device, CAN specific protocols
will wrongly interpret this pointer, which will cause system crashes.
Mostly this issue is visible in the CAN_J1939 stack.

To fix this issue, we request a dedicated CAN pointer within the
net_device struct.

Reported-by: syzbot+5138c4dd15a0401bec7b@syzkaller.appspotmail.com
Fixes: 20dd3850bcf8 ("can: Speed up CAN frame receiption by using ml_priv")
Fixes: ffd956eef69b ("can: introduce CAN midlayer private and allocate it automatically")
Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol")
Fixes: 497a5757ce4e ("tun: switch to net core provided statistics counters")
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Link: https://lore.kernel.org/r/20210223070127.4538-1-o.rempel@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
can: make use of preallocated can_ml_priv for per device struct can_dev_rcv_lists 2019-09-04T11:29:15+00:00 Marc Kleine-Budde mkl@pengutronix.de 2018-10-08T07:02:39+00:00 8df9ffb888c021fa68f9075d545f2ec5eca37200 This patch removes the old method of allocating the per device protocol specific memory via a netdevice_notifier. This had the drawback, that the allocation can fail, leading to a lot of null pointer checks in the code. This also makes the live cycle management of this memory quite complicated. This patch switches from the allocating the struct can_dev_rcv_lists in a NETDEV_REGISTER call to using the dev->ml_priv, which is allocated by the driver since the previous patch. Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> Acked-by: Oliver Hartkopp <socketcan@hartkopp.net> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> 
This patch removes the old method of allocating the per device protocol
specific memory via a netdevice_notifier. This had the drawback, that
the allocation can fail, leading to a lot of null pointer checks in the
code. This also makes the live cycle management of this memory quite
complicated.

This patch switches from the allocating the struct can_dev_rcv_lists in
a NETDEV_REGISTER call to using the dev->ml_priv, which is allocated by
the driver since the previous patch.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
can: introduce CAN midlayer private and allocate it automatically 2019-09-04T11:29:14+00:00 Marc Kleine-Budde mkl@pengutronix.de 2018-10-08T07:02:38+00:00 ffd956eef69b212a724b1cc4cdc61828f3ad9104 This patch introduces the CAN midlayer private structure ("struct can_ml_priv") which should be used to hold protocol specific per device data structures. For now it's only member is "struct can_dev_rcv_lists". The CAN midlayer private is allocated via alloc_netdev()'s private and assigned to "struct net_device::ml_priv" during device creation. This is done transparently for CAN drivers using alloc_candev(). The slcan, vcan and vxcan drivers which are not using alloc_candev() have been adopted manually. The memory layout of the netdev_priv allocated via alloc_candev() will looke like this: +-------------------------+ | driver's priv | +-------------------------+ | struct can_ml_priv | +-------------------------+ | array of struct sk_buff | +-------------------------+ Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> 
This patch introduces the CAN midlayer private structure ("struct
can_ml_priv") which should be used to hold protocol specific per device
data structures. For now it's only member is "struct can_dev_rcv_lists".

The CAN midlayer private is allocated via alloc_netdev()'s private and
assigned to "struct net_device::ml_priv" during device creation. This is
done transparently for CAN drivers using alloc_candev(). The slcan, vcan
and vxcan drivers which are not using alloc_candev() have been adopted
manually. The memory layout of the netdev_priv allocated via
alloc_candev() will looke like this:

  +-------------------------+
  | driver's priv           |
  +-------------------------+
  | struct can_ml_priv      |
  +-------------------------+
  | array of struct sk_buff |
  +-------------------------+

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
can: vcan: introduce pr_fmt and make use of it 2019-08-13T15:32:21+00:00 Marc Kleine-Budde mkl@pengutronix.de 2019-07-26T07:35:43+00:00 e83e416cdf4ff7f4815fe039a70688cf7e2d9d58 This patch introduces pr_fmt and makes use of it, also it converts a printk() to pr_info(). Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> 
This patch introduces pr_fmt and makes use of it, also it converts a
printk() to pr_info().

Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
can: vcan: remove unnecessary blank lines 2019-08-13T15:32:21+00:00 Marc Kleine-Budde mkl@pengutronix.de 2019-07-24T12:28:21+00:00 4248f5e02f2e23f75f15db15253137923209ad79 This patch removes unnecessary blank lines, so that checkpatch doesn't complain anymore. Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> 
This patch removes unnecessary blank lines, so that checkpatch doesn't
complain anymore.

Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
can: vcan: convert block comments to network style comments 2019-08-13T15:32:21+00:00 Marc Kleine-Budde mkl@pengutronix.de 2019-07-24T12:16:29+00:00 d569de814967362bdd69f073b88f1f1321097dee This patch converts all block comments to network subsystem style block comments. Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> 
This patch converts all block comments to network subsystem style block
comments.

Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
drivers/net: Use octal not symbolic permissions 2018-03-26T16:07:49+00:00 Joe Perches joe@perches.com 2018-03-23T22:54:39+00:00 d61e40385655fbba659fc3d81df9bdf1b848e263 Prefer the direct use of octal for permissions. Done with checkpatch -f --types=SYMBOLIC_PERMS --fix-inplace and some typing. Miscellanea: o Whitespace neatening around these conversions. Signed-off-by: Joe Perches <joe@perches.com> Reviewed-by: Wei Liu <wei.liu2@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
Prefer the direct use of octal for permissions.

Done with checkpatch -f --types=SYMBOLIC_PERMS --fix-inplace
and some typing.

Miscellanea:

o Whitespace neatening around these conversions.

Signed-off-by: Joe Perches <joe@perches.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
can: migrate documentation to restructured text 2018-01-26T09:46:44+00:00 Robert Schwebel r.schwebel@pengutronix.de 2018-01-24T10:19:11+00:00 7d5977394515ad3a636361ce23890863be6e0f70 The kernel documentation is now restructured text. Convert the SocketCAN documentation and include it in the toplevel kernel documentation. This patch doesn't do any content change. All references to can.txt in the code are converted to can.rst. Signed-off-by: Robert Schwebel <r.schwebel@pengutronix.de> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> 
The kernel documentation is now restructured text. Convert the SocketCAN
documentation and include it in the toplevel kernel documentation.

This patch doesn't do any content change.

All references to can.txt in the code are converted to can.rst.

Signed-off-by: Robert Schwebel <r.schwebel@pengutronix.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
can: enable CAN FD for virtual CAN devices by default 2017-06-09T12:39:02+00:00 Oliver Hartkopp socketcan@hartkopp.net 2017-06-02T17:37:30+00:00 97edec3a11cf6f73f2e45c3035b5ff8e4c3543dd CAN FD capable CAN interfaces can handle (classic) CAN 2.0 frames too. New users usually fail at their first attempt to explore CAN FD on virtual CAN interfaces due to the current CAN_MTU default. Set the MTU to CANFD_MTU by default to reduce this confusion. If someone *really* needs a 'classic CAN'-only device this can be set with the 'ip' tool with e.g. 'ip link set vcan0 mtu 16' as before. Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> 
CAN FD capable CAN interfaces can handle (classic) CAN 2.0 frames too.
New users usually fail at their first attempt to explore CAN FD on
virtual CAN interfaces due to the current CAN_MTU default.

Set the MTU to CANFD_MTU by default to reduce this confusion.
If someone *really* needs a 'classic CAN'-only device this can be set
with the 'ip' tool with e.g. 'ip link set vcan0 mtu 16' as before.

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>