[Bridge] [PATCH net-next] bridge: Add netlink support for vlan_protocol attribute

[Nikolay Aleksandrov]

> On Aug 28, 2015, at 4:06 AM, Toshiaki Makita <toshiaki.makita1 at gmail.com> wrote:
> 
> On 15/08/28 (金) 0:48, Nikolay Aleksandrov wrote:
>> 
>>> On Aug 26, 2015, at 11:00 PM, Toshiaki Makita <makita.toshiaki at lab.ntt.co.jp> wrote:
>>> 
>>> This enables bridge vlan_protocol to be configured through netlink.
>>> 
>>> When CONFIG_BRIDGE_VLAN_FILTERING is disabled, kernel behaves the
>>> same way as this feature is not implemented.
>>> 
>>> Signed-off-by: Toshiaki Makita <makita.toshiaki at lab.ntt.co.jp>
>>> ---
>>> include/uapi/linux/if_link.h |  1 +
>>> net/bridge/br_netlink.c      | 34 ++++++++++++++++++++++++++++++++++
>>> net/bridge/br_private.h      |  1 +
>>> net/bridge/br_vlan.c         | 35 +++++++++++++++++++++--------------
>>> 4 files changed, 57 insertions(+), 14 deletions(-)
>>> 
>> 
>> Nice, looks good. I have a similar patch as well and was going to ask wouldn’t it be
>> better to make empty stubs which return an error when vlan filtering isn’t configured
>> and drop the ifdefs in the netlink handling code ?
>> Similar to how vlan_filtering netlink attribute is handled in commit:
>> a7854037da00 ("bridge: netlink: add support for vlan_filtering attribute”)
>> 
>> Potential problem would be the return of the protocol, but I think if 0 is returned that
>> can be handled.
> 
> This is the exact reason why I didn't implement the stub.
> I wanted to avoid to charge userspace with that special casing 0.
> Also, this is consistent with sysfs implementation, which doesn't expose vlan_* entries when CONFIG_BRIDGE_VLAN_PROTOCOL is disabled.
> 
> Toshiaki Makita

Okay, fair enough.

Thanks,
 Nik