[PATCH 6.1 0251/1146] can: kvaser_usb_leaf: Fix bogus restart events

Greg Kroah-Hartman
2022-12-28T15:31:34Z

From: Anssi Hannula <anssi.hannula@bitwise.fi>

[ Upstream commit 90904d326269a38fe5dd895fb2db7c03199654c4 ]

When auto-restart is enabled, the kvaser_usb_leaf driver considers
transition from any state >= CAN_STATE_BUS_OFF as a bus-off recovery
event (restart).

However, these events may occur at interface startup time before
kvaser_usb_open() has set the state to CAN_STATE_ERROR_ACTIVE, causing
restarts counter to increase and CAN_ERR_RESTARTED to be sent despite no
actual restart having occurred.

Fix that by making the auto-restart condition checks more strict so that
they only trigger when the interface was actually in the BUS_OFF state.

Fixes: 080f40a6fa28 ("can: kvaser_usb: Add support for Kvaser CAN/USB devices")
Tested-by: Jimmy Assarsson <extja@kvaser.com>
Signed-off-by: Anssi Hannula <anssi.hannula@bitwise.fi>
Signed-off-by: Jimmy Assarsson <extja@kvaser.com>
Link: https://lore.kernel.org/all/20221010185237.319219-10-extja@kvaser.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/can/usb/kvaser_usb/kvaser_usb_leaf.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/can/usb/kvaser_usb/kvaser_usb_leaf.c b/drivers/net/can/usb/kvaser_usb/kvaser_usb_leaf.c
index 4f9c76f4d0da..fa940be4e1b0 100644
--- a/drivers/net/can/usb/kvaser_usb/kvaser_usb_leaf.c
+++ b/drivers/net/can/usb/kvaser_usb/kvaser_usb_leaf.c
@@ -898,7 +898,7 @@ static void kvaser_usb_leaf_tx_acknowledge(const struct kvaser_usb *dev,
context = &priv->tx_contexts[tid % dev->max_tx_urbs];

/* Sometimes the state change doesn't come after a bus-off event */
- if (priv->can.restart_ms && priv->can.state >= CAN_STATE_BUS_OFF) {
+ if (priv->can.restart_ms && priv->can.state == CAN_STATE_BUS_OFF) {
struct sk_buff *skb;
struct can_frame *cf;

@@ -998,7 +998,7 @@ kvaser_usb_leaf_rx_error_update_can_state(struct kvaser_usb_net_priv *priv,
}

if (priv->can.restart_ms &&
- cur_state >= CAN_STATE_BUS_OFF &&
+ cur_state == CAN_STATE_BUS_OFF &&
new_state < CAN_STATE_BUS_OFF)
priv->can.can_stats.restarts++;

@@ -1088,7 +1088,7 @@ static void kvaser_usb_leaf_rx_error(const struct kvaser_usb *dev,
}

if (priv->can.restart_ms &&
- old_state >= CAN_STATE_BUS_OFF &&
+ old_state == CAN_STATE_BUS_OFF &&
new_state < CAN_STATE_BUS_OFF) {
cf->can_id |= CAN_ERR_RESTARTED;
netif_carrier_on(priv->netdev);
--
2.35.1