On Sat, Dec 03, 2016 at 03:27:30PM -0800, Ben Pfaff wrote:

On Sat, Dec 03, 2016 at 10:22:28AM +0100, Michał Mirosław wrote:

quoted

This All-in-one patch removes abuse of VLAN CFI bit, so it can be passed
intact through linux networking stack.

Signed-off-by: Michał Mirosław <redacted>
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Dear NetDevs

I guess this needs to be split to the prep..convert[]..finish sequence,
but if you like it as is, then it's ready.

The biggest question is if the modified interface and vlan_present
is the way to go. This can be changed to use vlan_proto != 0 instead
of an extra flag bit.

As I can't test most of the driver changes, please look at them carefully.
OVS and bridge eyes are especially welcome.

This appears to change the established Open vSwitch userspace API.  You
can see that simply from the way that it changes the documentation for
the userspace API.  If I'm right about that, then this change will break
all userspace programs that use the Open vSwitch kernel module,
including Open vSwitch itself.

If I understood the code correctly, it does change expected meaning for
the (unlikely?) case of header truncated just before the VLAN TCI - it will
be impossible to differentiate this case from the VLAN TCI == 0.

I guess this is a problem with OVS API, because it doesn't directly show
the "missing" state of elements, but relies on an "invalid" value.

I can probably change the code to mask this change in the OVS code (by keeping
the CFI/DEI bit unusable). This somehow feels wrong, though.

Best Regards,
Michał Mirosław