Le mercredi 16 juin 2010 à 15:28 +0200, Pedro Garcia a écrit :

In my understanding, 802.1p is a "subset" of 802.1q, and they share the 
protocol number. We can do a 802.1p module, but in the end it will end
up reusing most of the code in 802.1q.

I was more thinking of a default ETH_P_8021Q rx handler (aka
vlan_skb_recv_minimal) with minimum handling (only accept vid=0 frames),
being overridden by real 8021q handler if module loaded/present.

In any case defining a VLAN 0 ends up usually in problems with which table 
the ARP entries get stored in. This patch solves the problem to whom 
is not using VLAN 0 explicitly, but if somebody is using VLAN 0 tagging
it will work (whatever "work" means) as before.

Probably a definitive fix would be not to allow the definition of VLAN 0 
in 802.1q module and provide some other way to tag priority packets without
using a subinterface (maybe in the same module or a new 8021p one). I am 
having a look at the kernel to see what happens if we load two modules for 
the same protocol. 

By the way, the changelog I have to write is just the text before the 
patch?

Yes, you can take a look on any patch around for examples, like...

git show 6e327c11a91d190650df9aabe7d3694d4838bfa1

Check Documentation/SubmittingPatches   section 2)