Merge branch 'af-xdp-sock-diag'

Björn Töpel says:

====================
This series adds an AF_XDP sock_diag interface for querying sockets
from user-space. Tools like iproute2 ss(8) can use this interface to
list open AF_XDP sockets.

The diagnostic provides information about the Rx/Tx/fill/completetion
rings, umem, memory usage and such. For a complete list, please refer
to the xsk_diag.c file.

The AF_XDP sock_diag interface is optional, and can be built as a
module. A separate patch series, adding ss(8) iproute2 support, will
follow.

v1->v2:
  * Removed extra newline
  * Zero-out all user-space facing structures prior setting the
    members
  * Added explicit "pad" member in _msg struct
  * Removed unused variable "req" in xsk_diag_handler_dump()

Thanks to Daniel for reviewing the series!
====================

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>