netdev - [PATCH net-next 07/15] can: netlink: dump bitrate 0 if can

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Date:   Sun,  3 Jul 2022 12:14:21 +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,
        Dario Binacchi <dario.binacchi@...rulasolutions.com>,
        Marc Kleine-Budde <mkl@...gutronix.de>,
        Jeroen Hofstee <jhofstee@...tronenergy.com>
Subject: [PATCH net-next 07/15] can: netlink: dump bitrate 0 if can_priv::bittiming.bitrate is -1U

From: Dario Binacchi <dario.binacchi@...rulasolutions.com>

Upcoming changes on slcan driver will require you to specify a bitrate
of value -1 to prevent the open_candev() from failing but at the same
time highlighting that it is a fake value. In this case the command
`ip --details -s -s link show' would print 4294967295 as the bitrate
value. The patch change this value in 0.

Link: https://lore.kernel.org/all/20220628163137.413025-5-dario.binacchi@amarulasolutions.com
Suggested-by: Marc Kleine-Budde <mkl@...gutronix.de>
Signed-off-by: Dario Binacchi <dario.binacchi@...rulasolutions.com>
Tested-by: Jeroen Hofstee <jhofstee@...tronenergy.com>
Signed-off-by: Marc Kleine-Budde <mkl@...gutronix.de>
---
 drivers/net/can/dev/netlink.c | 3 ++-
 include/linux/can/bittiming.h | 2 ++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/can/dev/netlink.c b/drivers/net/can/dev/netlink.c
index 037824011266..8efa22d9f214 100644
--- a/drivers/net/can/dev/netlink.c
+++ b/drivers/net/can/dev/netlink.c
@@ -511,7 +511,8 @@ static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
 	if (priv->do_get_state)
 		priv->do_get_state(dev, &state);
 
-	if ((priv->bittiming.bitrate &&
+	if ((priv->bittiming.bitrate != CAN_BITRATE_UNSET &&
+	     priv->bittiming.bitrate != CAN_BITRATE_UNKNOWN &&
 	     nla_put(skb, IFLA_CAN_BITTIMING,
 		     sizeof(priv->bittiming), &priv->bittiming)) ||
 
diff --git a/include/linux/can/bittiming.h b/include/linux/can/bittiming.h
index 7ae21c0f7f23..ef0a77173e3c 100644
--- a/include/linux/can/bittiming.h
+++ b/include/linux/can/bittiming.h
@@ -11,6 +11,8 @@
 
 #define CAN_SYNC_SEG 1
 
+#define CAN_BITRATE_UNSET 0
+#define CAN_BITRATE_UNKNOWN (-1U)
 
 #define CAN_CTRLMODE_TDC_MASK					\
 	(CAN_CTRLMODE_TDC_AUTO | CAN_CTRLMODE_TDC_MANUAL)
-- 
2.35.1