Re: Raw can socket close and disabling filters

[Oliver Hartkopp <socketcan@hartkopp.net>]

On 04/25/2016 09:19 AM, laurent vaudoit wrote:

>> So when the notifier runs with NETDEV_UNREGISTER it will remove the filters
>> & bind status.
>>
>> In this case the block in raw_release() won't have anything to do to release
>> the filters and the bind state, right?
>
> i agree with this. The fact is that on my setup i need to send an
> information to another µc when releasing a socket on a device, and so
> my specific code was done in the release function, after the
> unregister.

I think using raw_release() as trigger is always a good choice.

> This is how i've seen this behaviour.

Interesting information. I didn't know about the notifier running at 
unregister_netdevice_notifier() time.

>> Looks double work - but I wonder why we can rely on a notifier call when we
>> call unregister_netdevice_notifier() ??
>
> For me, the disable_all_filter part of code in release can not be
> called, as the ro->bound will allways be 0.

The question remains whether we can really rely on the notifier call 
which is obviously invoked by unregister_netdevice_notifier() ...
I'll have to dig if this behaviour is intentional and documented.
Until then I feel better to leave it as-is.

Regards,
Oliver