Merge branch 'vsock-sockmap-support'

Bobby Eshleman says:

====================
Add support for sockmap to vsock.

We're testing usage of vsock as a way to redirect guest-local UDS
requests to the host and this patch series greatly improves the
performance of such a setup.

Compared to copying packets via userspace, this improves throughput by
121% in basic testing.

Tested as follows.

Setup: guest unix dgram sender -> guest vsock redirector -> host vsock
server
Threads: 1
Payload: 64k
No sockmap:
- 76.3 MB/s
- The guest vsock redirector was
"socat VSOCK-CONNECT:2:1234 UNIX-RECV:/path/to/sock"
Using sockmap (this patch):
- 168.8 MB/s (+121%)
- The guest redirector was a simple sockmap echo server,
redirecting unix ingress to vsock 2:1234 egress.
- Same sender and server programs

*Note: these numbers are from RFC v1

Only the virtio transport has been tested. The loopback transport was
used in writing bpf/selftests, but not thoroughly tested otherwise.

This series requires the skb patch.

Changes in v4:
- af_vsock: fix parameter alignment in vsock_dgram_recvmsg()
- af_vsock: add TCP_ESTABLISHED comment in vsock_dgram_connect()
- vsock/bpf: change ret type to bool

Changes in v3:
- vsock/bpf: Refactor wait logic in vsock_bpf_recvmsg() to avoid
backwards goto
- vsock/bpf: Check psock before acquiring slock
- vsock/bpf: Return bool instead of int of 0 or 1
- vsock/bpf: Wrap macro args __sk/__psock in parens
- vsock/bpf: Place comment trailer */ on separate line

Changes in v2:
- vsock/bpf: rename vsock_dgram_* -> vsock_*
- vsock/bpf: change sk_psock_{get,put} and {lock,release}_sock() order
to minimize slock hold time
- vsock/bpf: use "new style" wait
- vsock/bpf: fix bug in wait log
- vsock/bpf: add check that recvmsg sk_type is one dgram, seqpacket, or
stream. Return error if not one of the three.
- virtio/vsock: comment __skb_recv_datagram() usage
- virtio/vsock: do not init copied in read_skb()
- vsock/bpf: add ifdef guard around struct proto in dgram_recvmsg()
- selftests/bpf: add vsock loopback config for aarch64
- selftests/bpf: add vsock loopback config for s390x
- selftests/bpf: remove vsock device from vmtest.sh qemu machine
- selftests/bpf: remove CONFIG_VIRTIO_VSOCKETS=y from config.x86_64
- vsock/bpf: move transport-related (e.g., if (!vsk->transport)) checks
out of fast path
====================

Signed-off-by: Bobby Eshleman <bobby.eshleman@bytedance.com>
Signed-off-by: David S. Miller <davem@davemloft.net>