netdev - [PATCH net 15/17] can: kvaser_usb_leaf: Fix bogus restart events

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Message-Id: <20220920092915.921613-16-mkl@pengutronix.de>
Date:   Tue, 20 Sep 2022 11:29:13 +0200
From:   Marc Kleine-Budde <mkl@...gutronix.de>
To:     netdev@...r.kernel.org
Cc:     davem@...emloft.net, kuba@...nel.org, linux-can@...r.kernel.org,
        kernel@...gutronix.de, Anssi Hannula <anssi.hannula@...wise.fi>,
        stable@...r.kernel.org, Jimmy Assarsson <extja@...ser.com>,
        Marc Kleine-Budde <mkl@...gutronix.de>
Subject: [PATCH net 15/17] can: kvaser_usb_leaf: Fix bogus restart events

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

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.

Cc: stable@...r.kernel.org
Fixes: 080f40a6fa28 ("can: kvaser_usb: Add support for Kvaser CAN/USB devices")
Tested-by: Jimmy Assarsson <extja@...ser.com>
Signed-off-by: Anssi Hannula <anssi.hannula@...wise.fi>
Signed-off-by: Jimmy Assarsson <extja@...ser.com>
Link: https://lore.kernel.org/all/20220903182559.189-13-extja@kvaser.com
Signed-off-by: Marc Kleine-Budde <mkl@...gutronix.de>
---
 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 f8a12a285050..3e31a9ebea88 100644
--- a/drivers/net/can/usb/kvaser_usb/kvaser_usb_leaf.c
+++ b/drivers/net/can/usb/kvaser_usb/kvaser_usb_leaf.c
@@ -901,7 +901,7 @@ 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;
 
@@ -1018,7 +1018,7 @@ 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++;
 
@@ -1111,7 +1111,7 @@ 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