[ovs-dev] [PATCH] faq: Mention Linux kernel versions supported by 2.13.x.

[Gregory Rose]

On 5/18/2020 7:26 PM, Han Zhou wrote:
> On Thu, May 14, 2020 at 10:48 AM Gregory Rose <gvrose8192 at gmail.com> wrote:
>>
>>
>>
>> On 5/14/2020 10:36 AM, Ben Pfaff wrote:
>>> This is based on acinclude.m4 in branch-2.13, which rejects anything
>>> newer than 5.0.
>>>
>>> Reported-by: Han Zhou <hzhou at ovn.org>
>>> Signed-off-by: Ben Pfaff <blp at ovn.org>
>>> ---
>>>    Documentation/faq/releases.rst | 1 +
>>>    1 file changed, 1 insertion(+)
>>>
>>> diff --git a/Documentation/faq/releases.rst
> b/Documentation/faq/releases.rst
>>> index 748540b91634..f9c5d7c7ff13 100644
>>> --- a/Documentation/faq/releases.rst
>>> +++ b/Documentation/faq/releases.rst
>>> @@ -70,6 +70,7 @@ Q: What Linux kernel versions does each Open vSwitch
> release work with?
>>>        2.10.x       3.10 to 4.17
>>>        2.11.x       3.10 to 4.18
>>>        2.12.x       3.10 to 5.0
>>> +    2.13.x       3.10 to 5.0
>>>        2.14.x       3.10 to 5.5
>>>        ============ ==============
>>>
>>>
>>
>> LGTM
>>
>> Acked-by: Greg Rose <gvrose8192 at gmail.com>
> 
> Thanks Ben and Greg. I just encountered an compiling error with master
> against 2.13.0 kernel:
> /home/hzhou/src/ovs/_build_kernel_3.13/datapath/linux/flow_table.c: In
> function ‘__table_instance_destroy’:
> /home/hzhou/src/ovs/_build_kernel_3.13/datapath/linux/flow_table.c:156:2:
> error: implicit declaration of function ‘kvfree’
> [-Werror=implicit-function-declaration]
>    kvfree(ti->buckets);
>    ^
> This was introduced by patch:
> ----- 8>< ------------------------------------- ><8 --------------------
> commit 4383e54bbe889754a4cdb0eef85f8cfe42a1dcff
> Author: Kent Overstreet <kent.overstreet at gmail.com>
> Date:   Wed Mar 27 08:32:16 2019 -0700
> 
>      datapath: convert to kvmalloc
> ----------------------------------------------------------------------------
> So it seems even kernel 3.13 was not supported for quite some time by at
> least OVS 2.12, 2.13. Shall we update the supported versions for the
> related branches to "3.14 to ..." instead of "3.10 to ..."? Or should we
> backport the kvfree() related changes from upstream to OVS tree and keep
> supporting the versions mentioned in this faq? I am not sure if any other
> errors will come once this kvfree() is fixed.
> 
> If we decide to do the later (i.e. backporting required changes for 3.13
> and older kernels), I will also need to update another patch (reviewed but
> waiting to be merged):
> https://patchwork.ozlabs.org/project/openvswitch/patch/1588554154-30608-1-git-send-email-hzhou@ovn.org/
> That patch would fail on kernel 3.13 too, because some hash related fields
> in skb were changed during 3.13 - 3.14. I have the v2 ready, but if we
> decide to drop the support for 3.13 because of the other compiling errors,
> I don't need to submit v2. Let me know :)
> 
> Thanks,
> Han
> 

Travis only checks from 3.16.  We should probably update the faq to
remove 3.10 from recent branches.  I can do that if we agree that's the
right thing to do.

- Greg