Subject: Re: Expose bond_xmit_hash function

From: Jiri Pirko <[email-masked]>
Date: Wed, 15 Jan 2020 10:45:13 +0100

Wed, Jan 15, 2020 at 09:01:43AM CET, [email-masked] wrote:
>RDMA over Converged Ethernet (RoCE) is a standard protocol which enables 
>RDMA’s efficient data transfer over Ethernet networks allowing transport 
>offload with hardware RDMA engine implementation.
>The RoCE v2 protocol exists on top of either the UDP/IPv4 or the 
>UDP/IPv6 protocol:
>
>--------------------------------------------------------------
>| L2 | L3 | UDP |IB BTH | Payload| ICRC | FCS |
>--------------------------------------------------------------
>
>When a bond LAG netdev is in use, we would like to have the same hash 
>result for RoCE packets as any other UDP packets, for this purpose we 
>need to expose the bond_xmit_hash function to external modules.
>If no objection, I will push a patch that export this symbol.

I don't think it is good idea to do it. It is an internal bond function.
it even accepts "struct bonding *bond". Do you plan to push netdev
struct as an arg instead? What about team? What about OVS bonding?

Also, you don't really need a hash, you need a slave that is going to be
used for a packet xmit.

I think this could work in a generic way:

struct net_device *master_xmit_slave_get(struct net_device *master_dev,
					 struct sk_buff *skb);