Re: [PATCH v2 net-next] net/hsr: add protocol version to fill_info output

[Jakub Kicinski <kuba@kernel.org>]

On Thu, 25 Sep 2025 10:37:38 +0200 Fernando Fernandez Mancera wrote:
> > I'm not very familiar with HSR or PRP. But The PRP_V1 which has value
> > of 3 looks like a kernel-internal hack. Or does the protocol actually
> > specify value 3 to mean PRP?
> > 
> > I don't think there's anything particularly wrong with the code.
> > The version is for HSR because PRP only has one version, there's no
> > ambiguity.
> > 
> > But again, I'm just glancing at the code I could be wrong..
> >   
> 
> No you are right, this is a hack made to integrate PRP with HSR driver. 
> PRP does not have a version other than PRP_V1 therefore it does not make 
> much sense to configure it. Having said that, I think it's weird to 
> report HSR_VERSION 3 but fail when configuring it.
> 
> IMHO HSR_VERSION should be hidden for PRP or it should be possible to 
> configure it to "3" (which now that you say it, it looks weird).

I think we're in agreement then? i was suggesting:

--- a/net/hsr/hsr_netlink.c
+++ b/net/hsr/hsr_netlink.c
@@ -166,6 +166,8 @@ static int hsr_fill_info(struct sk_buff *skb, const struct net_device *dev)
 		goto nla_put_failure;
 	if (hsr->prot_version == PRP_V1)
 		proto = HSR_PROTOCOL_PRP;
+	else if (nla_put_u8(skb, IFLA_HSR_VERSION, hsr->prot_version))
+		goto nla_put_failure;
 	if (nla_put_u8(skb, IFLA_HSR_PROTOCOL, proto))
 		goto nla_put_failure;

This will not report the HSR version if prot is PRP