diff mbox series

[v3,05/13] can: netlink: dump bitrate 0 if can_priv::bittiming.bitrate is -1U

Message ID 20220612213927.3004444-6-dario.binacchi@amarulasolutions.com
State New
Headers
Series can: slcan: extend supported features |

Commit Message

Dario Binacchi June 12, 2022, 9:39 p.m. UTC 
Adding Netlink support to the slcan driver made it necessary to set the
bitrate to a fake value (-1U) to prevent open_candev() from failing. 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.

Suggested-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
---

(no changes since v1)

 drivers/net/can/dev/netlink.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

Comments

Marc Kleine-Budde June 13, 2022, 7:10 a.m. UTC | #1 
On 12.06.2022 23:39:19, Dario Binacchi wrote:
> Adding Netlink support to the slcan driver made it necessary to set the
> bitrate to a fake value (-1U) to prevent open_candev() from failing. 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.
> 
> Suggested-by: Marc Kleine-Budde <mkl@pengutronix.de>
> Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
> ---
> 
> (no changes since v1)
> 
>  drivers/net/can/dev/netlink.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/can/dev/netlink.c b/drivers/net/can/dev/netlink.c
> index 7633d98e3912..788a6752fcc7 100644
> --- a/drivers/net/can/dev/netlink.c
> +++ b/drivers/net/can/dev/netlink.c
> @@ -505,11 +505,16 @@ static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
>  	struct can_ctrlmode cm = {.flags = priv->ctrlmode};
>  	struct can_berr_counter bec = { };
>  	enum can_state state = priv->state;
> +	__u32 bitrate = priv->bittiming.bitrate;
> +	int ret = 0;
>  
>  	if (priv->do_get_state)
>  		priv->do_get_state(dev, &state);
>  
> -	if ((priv->bittiming.bitrate &&

What about changing this line to:

        if ((priv->bittiming.bitrate && priv->bittiming.bitrate != -1 &&

This would make the code a lot cleaner. Can you think of a nice macro
name for the -1?

0 could be CAN_BITRATE_UNCONFIGURED or _UNSET. For -1 I cannot find a
catchy name, something like CAN_BITRATE_CONFIGURED_UNKOWN or
SET_UNKNOWN.

The macros can be added to bittiming.h and be part of this patch. Ofq
course the above code (and slcan.c) would make use of the macros instead
of using 0 and -1.

Marc
Dario Binacchi June 13, 2022, 8:44 p.m. UTC | #2 
On Mon, Jun 13, 2022 at 9:11 AM Marc Kleine-Budde <mkl@pengutronix.de> wrote:
>
> On 12.06.2022 23:39:19, Dario Binacchi wrote:
> > Adding Netlink support to the slcan driver made it necessary to set the
> > bitrate to a fake value (-1U) to prevent open_candev() from failing. 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.
> >
> > Suggested-by: Marc Kleine-Budde <mkl@pengutronix.de>
> > Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
> > ---
> >
> > (no changes since v1)
> >
> >  drivers/net/can/dev/netlink.c | 12 +++++++++---
> >  1 file changed, 9 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/net/can/dev/netlink.c b/drivers/net/can/dev/netlink.c
> > index 7633d98e3912..788a6752fcc7 100644
> > --- a/drivers/net/can/dev/netlink.c
> > +++ b/drivers/net/can/dev/netlink.c
> > @@ -505,11 +505,16 @@ static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
> >       struct can_ctrlmode cm = {.flags = priv->ctrlmode};
> >       struct can_berr_counter bec = { };
> >       enum can_state state = priv->state;
> > +     __u32 bitrate = priv->bittiming.bitrate;
> > +     int ret = 0;
> >
> >       if (priv->do_get_state)
> >               priv->do_get_state(dev, &state);
> >
> > -     if ((priv->bittiming.bitrate &&
>
> What about changing this line to:
>
>         if ((priv->bittiming.bitrate && priv->bittiming.bitrate != -1 &&

That you are right. The code becomes much cleaner.

>
> This would make the code a lot cleaner. Can you think of a nice macro
> name for the -1?
>
> 0 could be CAN_BITRATE_UNCONFIGURED or _UNSET. For -1 I cannot find a
> catchy name, something like CAN_BITRATE_CONFIGURED_UNKOWN or
> SET_UNKNOWN.
>

Personally I would use CAN_BITRATE_UNSET (0) and CAN_BITRATE_UNKNOWN (-1).
Let me know what your ultimate preference is.

Thanks and regards,
Dario

> The macros can be added to bittiming.h and be part of this patch. Ofq
> course the above code (and slcan.c) would make use of the macros instead
> of using 0 and -1.
>
> Marc
>
> --
> Pengutronix e.K.                 | Marc Kleine-Budde           |
> Embedded Linux                   | https://www.pengutronix.de  |
> Vertretung West/Dortmund         | Phone: +49-231-2826-924     |
> Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-5555 |
Marc Kleine-Budde June 14, 2022, 7:24 a.m. UTC | #3 
On 13.06.2022 22:44:12, Dario Binacchi wrote:
> On Mon, Jun 13, 2022 at 9:11 AM Marc Kleine-Budde <mkl@pengutronix.de> wrote:
> > This would make the code a lot cleaner. Can you think of a nice macro
> > name for the -1?
> >
> > 0 could be CAN_BITRATE_UNCONFIGURED or _UNSET. For -1 I cannot find a
> > catchy name, something like CAN_BITRATE_CONFIGURED_UNKOWN or
> > SET_UNKNOWN.
> >
> 
> Personally I would use CAN_BITRATE_UNSET (0) and CAN_BITRATE_UNKNOWN (-1).
> Let me know what your ultimate preference is.

Looks good.

Marc
diff mbox series

Patch

diff --git a/drivers/net/can/dev/netlink.c b/drivers/net/can/dev/netlink.c
index 7633d98e3912..788a6752fcc7 100644
--- a/drivers/net/can/dev/netlink.c
+++ b/drivers/net/can/dev/netlink.c
@@ -505,11 +505,16 @@  static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
 	struct can_ctrlmode cm = {.flags = priv->ctrlmode};
 	struct can_berr_counter bec = { };
 	enum can_state state = priv->state;
+	__u32 bitrate = priv->bittiming.bitrate;
+	int ret = 0;
 
 	if (priv->do_get_state)
 		priv->do_get_state(dev, &state);
 
-	if ((priv->bittiming.bitrate &&
+	if (bitrate == -1U)
+		priv->bittiming.bitrate = 0;
+
+	if ((bitrate &&
 	     nla_put(skb, IFLA_CAN_BITTIMING,
 		     sizeof(priv->bittiming), &priv->bittiming)) ||
 
@@ -563,9 +568,10 @@  static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
 	    can_ctrlmode_ext_fill_info(skb, priv)
 	    )
 
-		return -EMSGSIZE;
+		ret = -EMSGSIZE;
 
-	return 0;
+	priv->bittiming.bitrate = bitrate;
+	return ret;
 }
 
 static size_t can_get_xstats_size(const struct net_device *dev)