From: Oliver Hartkopp <socketcan@hartkopp.net>
To: Fabio Baltieri <fabio.baltieri@gmail.com>
Cc: Kurt Van Dijck <kurt.van.dijck@eia.be>,
Marc Kleine-Budde <mkl@pengutronix.de>,
Wolfgang Grandegger <wg@grandegger.com>,
linux-kernel@vger.kernel.org, linux-can@vger.kernel.org
Subject: Re: [PATCH] can: rename LED trigger name on netdev renames
Date: Thu, 06 Sep 2012 21:31:07 +0200 [thread overview]
Message-ID: <5048F9FB.9020207@hartkopp.net> (raw)
In-Reply-To: <20120906185938.GA4043@gmail.com>
On 06.09.2012 20:59, Fabio Baltieri wrote:
> Hi Kurt,
>
> thanks for the patch!
>
> On Tue, Sep 04, 2012 at 11:29:11AM +0200, Kurt Van Dijck wrote:
>> The LED trigger name for CAN devices is based on the initial
>> CAN device name, but does never change. The LED trigger name
>> is not guaranteed to be unique in case of hotplugging CAN devices.
>>
>> This patch tries to address this problem by modifying the
>> LED trigger name according to the CAN device name when
>> the latter changes.
>
> That's an ideal solution, and I like the notifier implementation, but I
> see a couple of problems with it.
>
>> This patch is meant as illustration only.
>> In case of VCAN device rename, a segmentation fault will occur.
>>
>> Signed-off-by: Kurt Van Dijck <kurt.van.dijck@eia.be>
>> ---
>> drivers/net/can/led.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 57 insertions(+)
>>
>> diff --git a/drivers/net/can/led.c b/drivers/net/can/led.c
>> index eaa14ac..f62f908 100644
>> --- a/drivers/net/can/led.c
>> +++ b/drivers/net/can/led.c
>> @@ -12,6 +12,7 @@
>> #include <linux/slab.h>
>> #include <linux/netdevice.h>
>> #include <linux/can/dev.h>
>> +#include <linux/if_arp.h>
>>
>> #include <linux/can/led.h>
>>
>> @@ -87,3 +88,59 @@ void devm_can_led_init(struct net_device *netdev)
>> devres_add(&netdev->dev, res);
>> }
>> EXPORT_SYMBOL_GPL(devm_can_led_init);
>> +
>> +/*
>> + * NETDEV rename notifier to rename the associated led triggers too
>> + */
>> +static int can_led_notifier(struct notifier_block *nb, unsigned long msg,
>> + void *data)
>> +{
>> + struct net_device *netdev = (struct net_device *)data;
>> + struct can_priv *priv = netdev_priv(netdev);
>> + int busy = 0;
>> +
>> + if (!net_eq(dev_net(netdev), &init_net))
>> + return NOTIFY_DONE;
>> +
>> + if (netdev->type != ARPHRD_CAN)
>> + return NOTIFY_DONE;
>> +
>> + if (msg != NETDEV_CHANGENAME)
>> + return NOTIFY_DONE;
>
> That's the main problem, which I also got stuck into when I did my first
> can-led implementation. As LED structures are in netdev's private data,
> you can only use it if your driver is based on the can-dev API, and
> there are no way to be sure of that if you get outside driver's code
> itself.
>
> This would give problems with vcan, slcan, and probabily other
> non-mainlined drivers.
Do you think, this is really a problem?
If a driver decides not to use the can-dev framework it has to implement own
solutions or just adopt can-dev.
Regards,
Oliver
>
> Is there any way to register a notifier which fires only for devices
> registered with devm_can_led_init?
>
next prev parent reply other threads:[~2012-09-06 19:31 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-30 19:20 [PATCH can-next v3 1/2] can: add tx/rx LED trigger support Fabio Baltieri
2012-07-30 19:20 ` [PATCH can-next v3 2/2] can: flexcan: add " Fabio Baltieri
2012-07-30 21:17 ` [PATCH can-next v3 1/2] can: add tx/rx " Marc Kleine-Budde
2012-07-31 6:57 ` Fabio Baltieri
2012-07-31 7:10 ` Marc Kleine-Budde
2012-07-31 11:57 ` Fabio Baltieri
2012-07-31 12:00 ` Marc Kleine-Budde
2012-07-31 22:05 ` [PATCH can-next v4] " Fabio Baltieri
2012-08-01 9:36 ` Marc Kleine-Budde
2012-08-01 10:07 ` Marc Kleine-Budde
2012-08-01 10:30 ` Fabio Baltieri
2012-08-01 11:37 ` Marc Kleine-Budde
2012-08-01 11:49 ` [PATCH can-next v5 1/2] " Fabio Baltieri
2012-08-01 11:49 ` [PATCH can-next v5 2/2] can: flexcan: add " Fabio Baltieri
2012-08-01 11:53 ` Marc Kleine-Budde
2012-08-01 12:24 ` Fabio Baltieri
2012-08-01 12:30 ` Marc Kleine-Budde
2012-08-01 21:02 ` Marc Kleine-Budde
2012-08-01 11:59 ` [PATCH can-next v5 1/2] can: add tx/rx " Marc Kleine-Budde
2012-08-01 12:06 ` Oliver Hartkopp
2012-08-01 12:18 ` Marc Kleine-Budde
2012-08-01 18:21 ` [PATCH can-next v6] " Fabio Baltieri
2012-08-01 21:00 ` Marc Kleine-Budde
2012-08-01 22:38 ` Fabio Baltieri
2012-08-01 21:05 ` Oliver Hartkopp
2012-08-24 5:10 ` Kurt Van Dijck
2012-08-24 11:28 ` Marc Kleine-Budde
2012-08-24 12:42 ` Kurt Van Dijck
2012-08-24 22:01 ` Fabio Baltieri
2012-08-25 20:25 ` Kurt Van Dijck
2012-09-03 12:40 ` Marc Kleine-Budde
2012-09-03 18:13 ` Kurt Van Dijck
2012-09-03 18:29 ` Fabio Baltieri
2012-09-03 20:54 ` Oliver Hartkopp
2012-09-04 7:11 ` Kurt Van Dijck
2012-09-04 9:29 ` [PATCH] can: rename LED trigger name on netdev renames Kurt Van Dijck
2012-09-06 18:59 ` Fabio Baltieri
2012-09-06 19:31 ` Oliver Hartkopp [this message]
2012-09-06 20:46 ` Fabio Baltieri
2012-09-07 7:19 ` Kurt Van Dijck
2012-09-09 16:17 ` [PATCH v2] " Fabio Baltieri
2012-09-10 14:25 ` [PATCH] can: export a safe netdev_priv wrapper for candev Kurt Van Dijck
2012-09-10 18:22 ` Oliver Hartkopp
2012-09-10 18:29 ` Fabio Baltieri
2012-09-10 19:55 ` [PATCH v2] " Kurt Van Dijck
2012-09-10 14:28 ` [PATCH v3] can: rename LED trigger name on netdev renames Kurt Van Dijck
2012-09-10 18:25 ` Oliver Hartkopp
2012-09-10 18:40 ` Fabio Baltieri
2012-09-10 19:01 ` Oliver Hartkopp
2012-09-10 20:08 ` Kurt Van Dijck
2012-09-11 5:42 ` Oliver Hartkopp
2012-09-11 7:13 ` Fabio Baltieri
2012-09-12 7:22 ` Kurt Van Dijck
2012-09-11 8:05 ` Kurt Van Dijck
2012-09-10 20:06 ` [PATCH v4] " Kurt Van Dijck
2012-09-11 21:04 ` Fabio Baltieri
2012-09-04 20:15 ` [PATCH can-next v6] can: add tx/rx LED trigger support Fabio Baltieri
2012-09-06 10:33 ` Kurt Van Dijck
2012-09-06 11:17 ` Fabio Baltieri
2012-09-06 15:11 ` Kurt Van Dijck
2012-09-06 20:57 ` Fabio Baltieri
2012-09-07 7:04 ` Kurt Van Dijck
2012-09-07 18:59 ` Fabio Baltieri
2012-07-31 8:46 ` [PATCH can-next v3 1/2] " Wolfgang Grandegger
2012-07-31 10:12 ` Marc Kleine-Budde
2012-07-31 11:55 ` Fabio Baltieri
2012-07-31 12:14 ` Fabio Baltieri
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5048F9FB.9020207@hartkopp.net \
--to=socketcan@hartkopp.net \
--cc=fabio.baltieri@gmail.com \
--cc=kurt.van.dijck@eia.be \
--cc=linux-can@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mkl@pengutronix.de \
--cc=wg@grandegger.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).