[nfp] NIC stops transmitting for small MSS values when TSO is enabled

[Edwin Peer]

Description of problem:
When TCP Segmentation Offload (TSO) is enabled on Netronome Agilio SmartNICs, the interface TX ring hangs when sending packets that require more than 64 segments to send.

Steps to reproduce:
1. Enable TSO (ethtool -K <intf> tso on)
2. Run an iperf session with a suitably small MSS

Actual results:
The iperf traffic rate drops to zero, after which, the NIC accepts no more TX packets.

Expected results:
The iperf session should complete normally.

Suggested resolution:
This bug has been fixed in version 2.0.4 of the Agilio SmartNIC firmware available in the upstream linux-firmware repository as of commit 2a91ed954213eabc90154ccd682cbfed7195c4b0.

https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/commit/?id=2a91ed954213eabc90154ccd682cbfed7195c4b0

Please backport as appropriate into Bionic and other releases.

[Imran Khakoo (imrankhakoo)]

This was tested on a new 18.04 daily build and was found to be resolved.

[Ads20000 (ads20000)]

Does that mean you can close this bug as Fix Released then (presumably Invalid for Backports)? :)

[Imran Khakoo (imrankhakoo)]

@Edwin Peer or @Simon Horman, kindly close the bug.