linux-stable.git/drivers/net/can/dev/netlink.c, branch linux-5.15.y

can: netlink: allow configuring of fixed data bit rates without need for do_set_data_bittiming callback

2022-08-17T12:23:20+00:00

[ Upstream commit ec30c109391c5eac9b1d689a61e4bfed88148947 ]

This patch is similar to 7e193a42c37c ("can: netlink: allow
configuring of fixed bit rates without need for do_set_bittiming
callback") but for data bit rates instead of bit rates.

Usually CAN devices support configurable data bit rates. The limits
are defined by struct can_priv::data_bittiming_const. Another way is
to implement the struct can_priv::do_set_data_bittiming callback.

If the bit rate is configured via netlink, the can_changelink()
function checks that either can_priv::data_bittiming_const or struct
can_priv::do_set_data_bittiming is implemented.

In commit 431af779256c ("can: dev: add CAN interface API for fixed
bitrates") an API for configuring bit rates on CAN interfaces that
only support fixed bit rates was added. The supported bit rates are
defined by struct can_priv::bitrate_const.

However the above mentioned commit forgot to add the struct
can_priv::data_bitrate_const to the check in can_changelink().

In order to avoid to implement a no-op can_priv::do_set_data_bittiming
callback on devices with fixed data bit rates, extend the check in
can_changelink() accordingly.

Link: https://lore.kernel.org/all/20220613143633.4151884-1-mkl@pengutronix.de
Fixes: 431af779256c ("can: dev: add CAN interface API for fixed bitrates")
Acked-by: Max Staudt 
Signed-off-by: Marc Kleine-Budde 
Signed-off-by: Sasha Levin

can: netlink: allow configuring of fixed bit rates without need for do_set_bittiming callback

2022-08-17T12:23:20+00:00

[ Upstream commit 7e193a42c37cf40eba8ac5af2d5e8eeb8b9506f9 ]

Usually CAN devices support configurable bit rates. The limits are
defined by struct can_priv::bittiming_const. Another way is to
implement the struct can_priv::do_set_bittiming callback.

If the bit rate is configured via netlink, the can_changelink()
function checks that either can_priv::bittiming_const or struct
can_priv::do_set_bittiming is implemented.

In commit 431af779256c ("can: dev: add CAN interface API for fixed
bitrates") an API for configuring bit rates on CAN interfaces that
only support fixed bit rates was added. The supported bit rates are
defined by struct can_priv::bitrate_const.

However the above mentioned commit forgot to add the struct
can_priv::bitrate_const to the check in can_changelink().

In order to avoid to implement a no-op can_priv::do_set_bittiming
callback on devices with fixed bit rates, extend the check in
can_changelink() accordingly.

Link: https://lore.kernel.org/all/20220611144248.3924903-1-mkl@pengutronix.de
Fixes: 431af779256c ("can: dev: add CAN interface API for fixed bitrates")
Reported-by: Max Staudt 
Signed-off-by: Marc Kleine-Budde 
Signed-off-by: Sasha Levin

can: netlink: allow user to turn off unsupported features

2021-08-19T13:07:03+00:00

The sanity checks on the control modes will reject any request related
to an unsupported features, even turning it off.

Example on an interface which does not support CAN-FD:

$ ip link set can0 type can bitrate 500000 fd off
RTNETLINK answers: Operation not supported

This patch lets such command go through (but requests to turn on an
unsupported feature are, of course, still denied).

Link: https://lore.kernel.org/r/20210815033248.98111-2-mailhol.vincent@wanadoo.fr
Signed-off-by: Vincent Mailhol 
Signed-off-by: Marc Kleine-Budde

can: netlink: remove redundant check in can_validate()

2021-07-25T09:36:25+00:00

can_validate() does a first check:

|	if (is_can_fd) {
|		if (!data[IFLA_CAN_BITTIMING] || !data[IFLA_CAN_DATA_BITTIMING])
|			return -EOPNOTSUPP;
|	}

If that first if succeeds, we know that if is_can_fd is true then
data[IFLA_CAN_BITTIMING is set.

However, the next if switch does not leverage on above knowledge and
redoes the check:

| 	if (data[IFLA_CAN_DATA_BITTIMING]) {
|		if (!is_can_fd || !data[IFLA_CAN_BITTIMING])
|		                   ^~~~~~~~~~~~~~~~~~~~~~~~
| 			return -EOPNOTSUPP;
| 	}

This patch removes that redundant check.

Link: https://lore.kernel.org/r/20210603151550.140727-2-mailhol.vincent@wanadoo.fr
Signed-off-by: Vincent Mailhol 
Signed-off-by: Marc Kleine-Budde

can: netlink: clear data_bittiming if FD is turned off

2021-07-25T09:36:25+00:00

When the FD is turned off through the netlink interface, the data bit
timing values still remain in data_bittiming and are displayed despite
of the feature being disabled.

Example:

| $ ip link set can0 type can bitrate 500000 dbitrate 2000000 fd on
| $ ip --details link show can0
| 1:  can0:  mtu 72 qdisc pfifo_fast state DOWN mode DEFAULT group default qlen 10
|     link/can  promiscuity 0 minmtu 0 maxmtu 0
|     can  state STOPPED restart-ms 0
| 	  bitrate 500000 sample-point 0.875
| 	  tq 12 prop-seg 69 phase-seg1 70 phase-seg2 20 sjw 1
| 	  ES582.1/ES584.1: tseg1 2..256 tseg2 2..128 sjw 1..128 brp 1..512 brp-inc 1
| 	  dbitrate 2000000 dsample-point 0.750
| 	  dtq 12 dprop-seg 14 dphase-seg1 15 dphase-seg2 10 dsjw 1
| 	  ES582.1/ES584.1: dtseg1 2..32 dtseg2 1..16 dsjw 1..8 dbrp 1..32 dbrp-inc 1
| 	  clock 80000000 numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535
|
| $ ip link set can0 type can bitrate 500000 fd off
| $ ip --details link show can0
| 1:  can0:  mtu 16 qdisc pfifo_fast state DOWN mode DEFAULT group default qlen 10
|     link/can  promiscuity 0 minmtu 0 maxmtu 0
|     can state STOPPED restart-ms 0
| 	  bitrate 500000 sample-point 0.875
| 	  tq 12 prop-seg 69 phase-seg1 70 phase-seg2 20 sjw 1
| 	  ES582.1/ES584.1: tseg1 2..256 tseg2 2..128 sjw 1..128 brp 1..512 brp-inc 1
| 	  dbitrate 2000000 dsample-point 0.750
| 	  dtq 12 dprop-seg 14 dphase-seg1 15 dphase-seg2 10 dsjw 1
| 	  ES582.1/ES584.1: dtseg1 2..32 dtseg2 1..16 dsjw 1..8 dbrp 1..32 dbrp-inc 1
| 	  clock 80000000 numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535

Remark: once FD is turned off, it is not possible to turn fd back on
and reuse the previously input data bit timing values:

| $ ip link set can0 type can bitrate 500000 fd on
| RTNETLINK answers: Operation not supported

This means that the user will need to re-configure the data bit timing
in order to turn fd on again.

Because old data bit timing values cannot be reused, this patch clears
priv->data_bit timing whenever FD is turned off. This way, the data
bit timing variables are not displayed anymore.

Link: https://lore.kernel.org/r/20210618081904.141114-2-mailhol.vincent@wanadoo.fr
Signed-off-by: Vincent Mailhol 
Signed-off-by: Marc Kleine-Budde

can: bittiming: add calculation for CAN FD Transmitter Delay Compensation (TDC)

2021-03-30T09:14:45+00:00

The logic for the tdco calculation is to just reuse the normal sample
point: tdco = sp. Because the sample point is expressed in tenth of
percent and the tdco is expressed in time quanta, a conversion is
needed.

At the end,
     ssp = tdcv + tdco
         = tdcv + sp.

Another popular method is to set tdco to the middle of the bit:
     tdc->tdco = can_bit_time(dbt) / 2
During benchmark tests, we could not find a clear advantages for one
of the two methods.

The tdco calculation is triggered each time the data_bittiming is
changed so that users relying on automated calculation can use the
netlink interface the exact same way without need of new parameters.
For example, a command such as:
	ip link set canX type can bitrate 500000 dbitrate 4000000 fd on
would trigger the calculation.

The user using CONFIG_CAN_CALC_BITTIMING who does not want automated
calculation needs to manually set tdco to zero.
For example with:
	ip link set canX type can tdco 0 bitrate 500000 dbitrate 4000000 fd on
(if the tdco parameter is provided in a previous command, it will be
overwritten).

If tdcv is set to zero (default), it is automatically calculated by
the transiver for each frame. As such, there is no code in the kernel
to calculate it.

tdcf has no automated calculation functions because we could not
figure out a formula for this parameter.

Link: https://lore.kernel.org/r/20210224002008.4158-6-mailhol.vincent@wanadoo.fr
Signed-off-by: Vincent Mailhol 
Signed-off-by: Marc Kleine-Budde

can: netlink: move '=' operators back to previous line (checkpatch fix)

2021-03-30T09:14:45+00:00

Fix the warning triggered by having an '=' at the beginning of the
line by moving it back to the previous line. Also replace all
indentations with a single space so that future entries can be more
easily added.

Extract of ./scripts/checkpatch.pl -f drivers/net/can/dev/netlink.c:

CHECK: Assignment operator '=' should be on the previous line
+       [IFLA_CAN_BITTIMING_CONST]
+                               = { .len = sizeof(struct can_bittiming_const) },

CHECK: Assignment operator '=' should be on the previous line
+       [IFLA_CAN_DATA_BITTIMING]
+                               = { .len = sizeof(struct can_bittiming) },

CHECK: Assignment operator '=' should be on the previous line
+       [IFLA_CAN_DATA_BITTIMING_CONST]
+                               = { .len = sizeof(struct can_bittiming_const) },

Link: https://lore.kernel.org/r/20210224002008.4158-4-mailhol.vincent@wanadoo.fr
Signed-off-by: Vincent Mailhol 
Signed-off-by: Marc Kleine-Budde

can: dev: Move device back to init netns on owning netns delete

2021-03-16T07:40:04+00:00

When a non-initial netns is destroyed, the usual policy is to delete
all virtual network interfaces contained, but move physical interfaces
back to the initial netns. This keeps the physical interface visible
on the system.

CAN devices are somewhat special, as they define rtnl_link_ops even
if they are physical devices. If a CAN interface is moved into a
non-initial netns, destroying that netns lets the interface vanish
instead of moving it back to the initial netns. default_device_exit()
skips CAN interfaces due to having rtnl_link_ops set. Reproducer:

  ip netns add foo
  ip link set can0 netns foo
  ip netns delete foo

WARNING: CPU: 1 PID: 84 at net/core/dev.c:11030 ops_exit_list+0x38/0x60
CPU: 1 PID: 84 Comm: kworker/u4:2 Not tainted 5.10.19 #1
Workqueue: netns cleanup_net
[] (unwind_backtrace) from [] (show_stack+0x10/0x14)
[] (show_stack) from [] (dump_stack+0x94/0xa8)
[] (dump_stack) from [] (__warn+0xb8/0x114)
[] (__warn) from [] (warn_slowpath_fmt+0x7c/0xac)
[] (warn_slowpath_fmt) from [] (ops_exit_list+0x38/0x60)
[] (ops_exit_list) from [] (cleanup_net+0x230/0x380)
[] (cleanup_net) from [] (process_one_work+0x1d8/0x438)
[] (process_one_work) from [] (worker_thread+0x64/0x5a8)
[] (worker_thread) from [] (kthread+0x148/0x14c)
[] (kthread) from [] (ret_from_fork+0x14/0x2c)

To properly restore physical CAN devices to the initial netns on owning
netns exit, introduce a flag on rtnl_link_ops that can be set by drivers.
For CAN devices setting this flag, default_device_exit() considers them
non-virtual, applying the usual namespace move.

The issue was introduced in the commit mentioned below, as at that time
CAN devices did not have a dellink() operation.

Fixes: e008b5fc8dc7 ("net: Simplfy default_device_exit and improve batching.")
Link: https://lore.kernel.org/r/20210302122423.872326-1-martin@strongswan.org
Signed-off-by: Martin Willi 
Signed-off-by: Marc Kleine-Budde

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2021-01-29T01:09:31+00:00

drivers/net/can/dev.c
  b552766c872f ("can: dev: prevent potential information leak in can_fill_info()")
  3e77f70e7345 ("can: dev: move driver related infrastructure into separate subdir")
  0a042c6ec991 ("can: dev: move netlink related code into seperate file")

  Code move.

drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
  57ac4a31c483 ("net/mlx5e: Correctly handle changing the number of queues when the interface is down")
  214baf22870c ("net/mlx5e: Support HTB offload")

  Adjacent code changes

net/switchdev/switchdev.c
  20776b465c0c ("net: switchdev: don't set port_obj_info->handled true when -EOPNOTSUPP")
  ffb68fc58e96 ("net: switchdev: remove the transaction structure from port object notifiers")
  bae33f2b5afe ("net: switchdev: remove the transaction structure from port attributes")

  Transaction parameter gets dropped otherwise keep the fix.

Signed-off-by: Jakub Kicinski

can: dev: move netlink related code into seperate file

2021-01-13T08:42:59+00:00

This patch moves the netlink related code of the CAN device infrastructure into
a separate file.

Reviewed-by: Vincent Mailhol 
Link: https://lore.kernel.org/r/20210111141930.693847-7-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde