Re: [PATCH net-next v1] net/core: Replace driver version to be kernel version

[Florian Fainelli <f.fainelli@gmail.com>]

On 1/25/2020 11:24 AM, Leon Romanovsky wrote:
> On Sat, Jan 25, 2020 at 08:49:58PM +0200, Leon Romanovsky wrote:
>> On Sat, Jan 25, 2020 at 08:55:01AM -0800, Florian Fainelli wrote:
>>>
>>>
>>> On 1/25/2020 8:14 AM, Leon Romanovsky wrote:
>>>> From: Leon Romanovsky <leonro@mellanox.com>
>>>>
>>>> In order to stop useless driver version bumps and unify output
>>>> presented by ethtool -i, let's overwrite the version string.
>>>>
>>>> Before this change:
>>>> [leonro@erver ~]$ ethtool -i eth0
>>>> driver: virtio_net
>>>> version: 1.0.0
>>>> After this change:
>>>> [leonro@server ~]$ ethtool -i eth0
>>>> driver: virtio_net
>>>> version: 5.5.0-rc6+
>>>>
>>>> Signed-off-by: Leon Romanovsky <leonro@mellanox.com>> ---
>>>>  Changelog:
>>>>  v1: Resend per-Dave's request
>>>>      https://lore.kernel.org/linux-rdma/20200125.101311.1924780619716720495.davem@davemloft.net
>>>>      No changes at all and applied cleanly on top of "3333e50b64fe Merge branch 'mlxsw-Offload-TBF'"
>>>>  v0: https://lore.kernel.org/linux-rdma/20200123130541.30473-1-leon@kernel.org
>>>
>>> There does not appear to be any explanation why we think this is a good
>>> idea for *all* drivers, and not just the ones that are purely virtual?
>>
>> We beat this dead horse too many times already, latest discussion and
>> justification can be found in that thread.
>> https://lore.kernel.org/linux-rdma/20200122152627.14903-1-michal.kalderon@marvell.com/T/#md460ff8f976c532a89d6860411c3c50bb811038b
>>
>> However, it was discussed in ksummit mailing list too and overall
>> agreement that version exposed by in-tree modules are useless and
>> sometimes even worse. They mislead users to expect some features
>> or lack of them based on this arbitrary string.
>>
>>>
>>> Are you not concerned that this is ABI and that specific userland may be
>>> relying on a specific info format and we could now be breaking their
>>> version checks? I do not disagree that the version is not particularly
>>> useful for in-tree kernel, but this is ABI, and breaking user-space is
>>> usually a source of support questions.
>>
>> See this Linus's response:
>> "The unified policy is pretty much that version codes do not matter, do
>> not exist, and do not get updated.
>>
>> Things are supposed to be backwards and forwards compatible, because
>> we don't accept breakage in user space anyway. So versioning is
>> pointless, and only causes problems."
>> https://lore.kernel.org/ksummit-discuss/CA+55aFx9A=5cc0QZ7CySC4F2K7eYaEfzkdYEc9JaNgCcV25=rg@mail.gmail.com/
>>
>> I also don't think that declaring every print in the kernel as ABI is
>> good thing to do. We are not breaking binary ABI and continuing to
>> supply some sort of versioning, but in unified format and not in wild
>> west way like it is now.
>>
>> So bottom line, if some REAL user space application (not test suites) relies
>> on specific version reported from ethtool, it is already broken and can't work
>> sanely for stable@, distros and upstream kernels.
> 
> And about support questions,
> I'm already over-asked to update our mlx5 driver version every time some
> of our developers adds new feature (every week or two), which is insane.
> So I prefer to have one stable solution in the kernel.

Fair enough, can you spin a new version which provides this background
discussion and links into your commit message?
-- 
Florian