Re: [PATCH REPOST] docs: networking: Remove VLAN_TAG_PRESENT from openvswitch doc

From: Ilya Maximets
Date: Mon Feb 03 2025 - 08:41:26 EST


On 2/3/25 14:29, Michał Mirosław wrote:
> On Mon, Feb 03, 2025 at 12:30:12PM +0100, Andreas Karis wrote:
>> Since commit 0c4b2d370514 ("net: remove VLAN_TAG_PRESENT"), the kernel
>> no longer uses VLAN_TAG_PRESENT.
>> Update the openvswitch documentation which still contained an outdated
>> reference to VLAN_TAG_PRESENT.
>
> Hi, it would be best to extend this doc saying that the CFI bit is not
> usable in openvswitch (unlike in other parts of kernel).

FWIW, sch_frag does the same thing. So, it's not only openvswitch.
Though, yes, sch_frag is probably doing that because TC mimics what
OVS does.

>
> Nevertheless,
> Acked-by: Michał Mirosław <mirq-linux@xxxxxxxxxxxx>
>
>>
>> Signed-off-by: Andreas Karis <ak.karis@xxxxxxxxx>
>> ---
>> Documentation/networking/openvswitch.rst | 5 ++---
>> 1 file changed, 2 insertions(+), 3 deletions(-)
>>
>> diff --git a/Documentation/networking/openvswitch.rst b/Documentation/networking/openvswitch.rst
>> index 1a8353dbf1b6..8d2bbcb92286 100644
>> --- a/Documentation/networking/openvswitch.rst
>> +++ b/Documentation/networking/openvswitch.rst
>> @@ -230,9 +230,8 @@ an all-zero-bits vlan and an empty encap attribute, like this::
>> eth(...), eth_type(0x8100), vlan(0), encap()
>>
>> Unlike a TCP packet with source and destination ports 0, an
>> -all-zero-bits VLAN TCI is not that rare, so the CFI bit (aka
>> -VLAN_TAG_PRESENT inside the kernel) is ordinarily set in a vlan
>> -attribute expressly to allow this situation to be distinguished.
>> +all-zero-bits VLAN TCI is not that rare, so the CFI bit is ordinarily set
>> +in a vlan attribute expressly to allow this situation to be distinguished.
>> Thus, the flow key in this second example unambiguously indicates a
>> missing or malformed VLAN TCI.
>>
>> --
>> 2.48.1
>>
>