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

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

[Marc Kleine-Budde]

Usually CAN devices support freely 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.

Fixes: 431af779256c ("can: dev: add CAN interface API for fixed bitrates")
Reported-by: Max Staudt <max@enpas.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 drivers/net/can/dev/netlink.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/can/dev/netlink.c b/drivers/net/can/dev/netlink.c
index 7633d98e3912..667ddd28fcdc 100644
--- a/drivers/net/can/dev/netlink.c
+++ b/drivers/net/can/dev/netlink.c
@@ -176,7 +176,8 @@ static int can_changelink(struct net_device *dev, struct nlattr *tb[],
 		 * directly via do_set_bitrate(). Bail out if neither
 		 * is given.
 		 */
-		if (!priv->bittiming_const && !priv->do_set_bittiming)
+		if (!priv->bittiming_const && !priv->do_set_bittiming &&
+		    !priv->bitrate_const)
 			return -EOPNOTSUPP;
 
 		memcpy(&bt, nla_data(data[IFLA_CAN_BITTIMING]), sizeof(bt));
-- 
2.35.1

Re: [PATCH] can: netlink: allow configuring of fixed bit rates without need for do_set_bittiming callback

[Max Staudt]

Thank you!

As discussed, after 3 years of can327/elmcan with the dummy function, I
believe this to be thoroughly tested ;)

Tested-by: Max Staudt <max@enpas.org>