Reading Explicit Congestion Notification (ECN) for ROCE on Sysfs

[dasturiasArista]

Nvidia/Mellanox expose ROCE ECN information on sysfs on the path
/sys/class/net/<interface>/ecn/<protocol>/

There are 2 protocols Reaction Point (rp) and Notification point (np)

For each of the protocols they have a list of attributes:
/sys/class/net/<interface>/ecn/<protocol>/params/<requested attribute>

Each protocol will also if ECN is enabled per priority (where X is the
priority):
/sys/class/net/<interface>/ecn/<protocol>/enable/X

This is documented here
https://docs.nvidia.com/networking/display/mlnxofedv571020/explicit+congestion+notification+(ecn)

The attributes are documented here:
https://enterprise-support.nvidia.com/s/article/dcqcn-parameters

[discordianfish]

Needs updating but LGTM in general

[dasturiasArista]

Needs updating but LGTM in general

Thanks for the review! Happy to update whatever needs to be updated, but I'm not entirely clear what that is :). Are you referring to the commit history? Would it just the cleanest in that case to just create a new fork and PR?

[discordianfish]

@dasturiasArista No need for a new PR, I'd just squash your commits, rebase and then (force) push this branch again.

[dasturiasArista]

Hey sorry about this, but I was trying to update everything without creating a new PR, but looks like I did something and it closed out the PR. I created a new PR here: #695