On 02.07.2018 21:48, Corinna Vinschen wrote:
> Hi,
>
> the patch 1f7aa2bc268e, "r8169: simplify rtl_set_mac_address",
> introduced a regression found by trying to team a r8169 NIC.
>
Thanks for reporting!
> Try the following (assuming the r8169 NIC is eth0):
>
> $ nmcli con add type team con-name team0 ifname nm-team config \
> '{"runner": {"name": "lacp"}, "link_watch": {"name": "ethtool"}}' \
> ipv4.method disable ipv6.method ignore
> $ nmcli con add type ethernet ifname eth0 con-name team0.0 master nm-team
> $ nmcli con up team0.0
> $ teamdctl nm-team port present eth0
> command call failed (No such device)
>
> Bisecting turned up commit 1f7aa2bc268e, "r8169: simplify
> rtl_set_mac_address" as the culprit. Reverting this patch fixes
> the issue and the teamdctl call succeeds.
>
> The reason is apparently the usage of eth_mac_addr here. eth_mac_addr
> calls eth_prepare_mac_addr_change which checks for IFF_LIVE_ADDR_CHANGE.
> Debugging shows this flag not being set on r8169, thus
> eth_prepare_mac_addr_change returns -EBUSY (no idea why userspace claims
> "No such device", rather than "Device or resource busy", but that's not
> the point here).
>
> Note that other devices like igb, don't call eth_mac_addr either, but
> rather call memcpy by themselves to copy the new MAC, just as the
> original r8169 code did, too. Consequentially this problem is not
> present on igb.
>
Doing the memcpy directly in the driver (like it was before) would be
a solution, however I'd consider this more a workaround because purpose
of the core functions is to encapsulate such details.
> I suggest to revert this change in the first place, but I wonder if
> we're not just missing to set IFF_LIVE_ADDR_CHANGE in a lot of drivers.
>
I'd prefer to keep the code and set flag IFF_LIVE_ADDR_CHANGE in the
driver. Setting this flag via ethtool --set-priv-flags in theory would
also be an option, however the r8169 driver doesn't implement the
ethtool_ops set_priv_flags callback.
>
> Thanks,
> Corinna
>
Rgds, Heiner
