Messages in this thread | | | Date | Fri, 25 Feb 2022 13:58:02 +0200 | From | Vladimir Oltean <> | Subject | Re: [PATCH net-next v2 1/1] net: dsa: microchip: ksz9477: implement MTU configuration |
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On Fri, Feb 25, 2022 at 12:47:40PM +0100, Oleksij Rempel wrote: > On Thu, Feb 24, 2022 at 11:46:57AM +0200, Vladimir Oltean wrote: > > > So where is it failing exactly? Here I guess, because mtu_limit will be > > negative? > > > > mtu_limit = min_t(int, master->max_mtu, dev->max_mtu); > > old_master_mtu = master->mtu; > > new_master_mtu = largest_mtu + dsa_tag_protocol_overhead(cpu_dp->tag_ops); > > if (new_master_mtu > mtu_limit) > > return -ERANGE; > > > > I don't think we can work around it in DSA, it's garbage in, garbage out. > > > > In principle, I don't have such a big issue with writing the MTU > > register as part of the switch initialization, especially if it's global > > and not per port. But tell me something else. You pre-program the MTU > > with VLAN_ETH_FRAME_LEN + ETH_FCS_LEN, but in the MTU change procedure, > > you also add KSZ9477_INGRESS_TAG_LEN (2) to that. Is that needed at all? > > I expect that if it's needed, it's needed in both places. Can you > > sustain an iperf3 tcp session over a VLAN upper of a ksz9477 port? > > I suspect that the missing VLAN_HLEN is masking a lack of KSZ9477_INGRESS_TAG_LEN. > > Hm... I assume I need to do something like this: > - build kernel with BRIDGE_VLAN_FILTERING > - | > ip l a name br0 type bridge vlan_filtering 1 > ip l s dev br0 up > ip l s lan1 master br0 > ip l s dev lan1 up > bridge vlan add dev lan1 vid 5 pvid untagged > ip link add link br0 name vlan5 type vlan id 5 > > I use lan5@ksz for net boot. As soon as i link lan1@ksz to the br0 with > vlan_filtering enabled, the nfs on lan5 will be broken. Currently I have > no time to investigate it. I'll try to fix VLAN support in a separate > task. What will is acceptable way to proceed with MTU patch?
No bridge, why create a bridge? And even if you do, why add lan5 to it? The expectation is that standalone ports still remain functional when other ports join a bridge.
I was saying:
ip link set lan1 up ip link add link lan1 name lan1.5 type vlan id 5 ip addr add 192.168.100.1/24 dev lan1.5 && ip link set lan1.5 up iperf3 -c 192.168.100.2
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