[$] The intersection of mlx5, netdev, and lockdown

The NVIDIA Mellanox ConnectX HW family of adapters is a complex beast,supporting networking, InfiniBand, RDMA, and more. As a result, the mlx5kernel driver that supports this hardware is also complex, as is theinterface that it provides to user space. The mlx5 developers have, for awhile now, been proposingthe addition of a new control interface, in the form of a separate virtualdevice exported by the kernel, that would make vast amounts of debugginginformation available. This driver has encountered some significantopposition on its way toward the mainline, though, raising a number ofquestions about appropriate interfaces and when subsystem maintainers haveveto power over submissions.