netdev - Re: [PATCH net-next 0/7] net: network drivers should not depend on geneve/vxlan

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Date:	Wed, 20 Apr 2016 03:21:02 +0200
From:	Hannes Frederic Sowa <hannes@...essinduktion.org>
To:	David Miller <davem@...emloft.net>
Cc:	netdev@...r.kernel.org, jesse@...nel.org
Subject: Re: [PATCH net-next 0/7] net: network drivers should not depend on
 geneve/vxlan

On 20.04.2016 03:11, David Miller wrote:
> From: Hannes Frederic Sowa <hannes@...essinduktion.org>
> Date: Wed, 20 Apr 2016 03:06:13 +0200
> 
>> On Wed, Apr 20, 2016, at 02:27, David Miller wrote:
>>> From: Hannes Frederic Sowa <hannes@...essinduktion.org>
>>> Date: Mon, 18 Apr 2016 21:19:41 +0200
>>>
>>>> This patchset removes the dependency of network drivers on vxlan or
>>>> geneve, so those don't get autoloaded when the nic driver is loaded.
>>>>
>>>> Also audited the code such that vxlan_get_rx_port and geneve_get_rx_port
>>>> are not called without rtnl lock.
>>>
>>> In net-next, the 'qed' driver has tunneling offload support too.
>>> Don't you need to update this series to handle that driver as
>>> well?
>>
>> I audited qede as well:
>>
>> qede calls {vxlan,geneve}_get_rx_port only from ndo_open which isn't
>> reused anywhere else in the driver, only from ndo_open, which holds
>> rtnl_lock also. Thus the driver is safe and doesn't need a change.
> 
> I'm talking about your final patches which elide the dependencies.

The dependency will be removed with only the last two patches for all
drivers. The static inline functions {vxlan,geneve}_get_rx_port now
simply expand to a call to call_netdevice_notifiers, which is provided
by the core kernel and not by the vxlan or geneve module anymore.

During testing I saw that very often some drivers actually reused their
*_attach or *_open function from other callbacks, e.g. pci ones. While
they often didn't care about rtnl_lock, we now require that for the new
get_rx_port functions, thus I added them.

I hadn't had to modify all drivers with vxlan offloading support, e.g.
also mlx5 and the broadcom drivers, bnx2x and bnxt, were already fine.

Bye,
Hannes