2022-06-13 03:08:55

by Dario Binacchi

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

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 <[email protected]>
Signed-off-by: Dario Binacchi <[email protected]>
---

(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 &&
+ 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)
--
2.32.0


2022-06-13 07:15:41

by Marc Kleine-Budde

[permalink] [raw]
Subject: Re: [PATCH v3 05/13] can: netlink: dump bitrate 0 if can_priv::bittiming.bitrate is -1U

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 <[email protected]>
> Signed-off-by: Dario Binacchi <[email protected]>
> ---
>
> (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

--
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 |


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2022-06-13 21:58:25

by Dario Binacchi

[permalink] [raw]
Subject: Re: [PATCH v3 05/13] can: netlink: dump bitrate 0 if can_priv::bittiming.bitrate is -1U

On Mon, Jun 13, 2022 at 9:11 AM Marc Kleine-Budde <[email protected]> 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 <[email protected]>
> > Signed-off-by: Dario Binacchi <[email protected]>
> > ---
> >
> > (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 |



--

Dario Binacchi

Embedded Linux Developer

[email protected]

__________________________________


Amarula Solutions SRL

Via Le Canevare 30, 31100 Treviso, Veneto, IT

T. +39 042 243 5310
[email protected]

http://www.amarulasolutions.com

2022-06-14 07:27:50

by Marc Kleine-Budde

[permalink] [raw]
Subject: Re: [PATCH v3 05/13] can: netlink: dump bitrate 0 if can_priv::bittiming.bitrate is -1U

On 13.06.2022 22:44:12, Dario Binacchi wrote:
> On Mon, Jun 13, 2022 at 9:11 AM Marc Kleine-Budde <[email protected]> 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

--
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 |


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