[RFC PATCH v2 00/13] virtio/vsock: introduce SOCK_SEQPACKET support.

[Arseny Krasnov]

	This patchset impelements support of SOCK_SEQPACKET for virtio
transport.
	As SOCK_SEQPACKET guarantees to save record boundaries, so to
do it, new packet operation was added: it marks start of record (with
record length in header), such packet doesn't carry any data.  To send
record, packet with start marker is sent first, then all data is sent
as usual 'RW' packets. On receiver's side, length of record is known
from packet with start record marker. Now as  packets of one socket
are not reordered neither on vsock nor on vhost transport layers, such
marker allows to restore original record on receiver's side. If user's
buffer is smaller that record length, when all out of size data is
dropped.
	Maximum length of datagram is not limited as in stream socket,
because same credit logic is used. Difference with stream socket is
that user is not woken up until whole record is received or error
occurred. Implementation also supports 'MSG_EOR' and 'MSG_TRUNC' flags.
	Tests also implemented.

 Arseny Krasnov (13):
  af_vsock: implement 'vsock_wait_data()'.
  af_vsock: separate rx loops for STREAM/SEQPACKET.
  af_vsock: implement rx loops entry point
  af_vsock: replace previous stream rx loop.
  af_vsock: implement send logic for SOCK_SEQPACKET
  af_vsock: general support of SOCK_SEQPACKET type.
  af_vsock: update comments for stream sockets.
  virtio/vsock: dequeue callback for SOCK_SEQPACKET.
  virtio/vsock: implement fetch of record length
  virtio/vsock: update receive logic
  virtio/vsock: rest of SOCK_SEQPACKET support
  vhost/vsock: support for SOCK_SEQPACKET socket.
  vsock_test: add SOCK_SEQPACKET tests.

 drivers/vhost/vsock.c                   |   7 +-
 include/linux/virtio_vsock.h            |  12 +
 include/net/af_vsock.h                  |   6 +
 include/uapi/linux/virtio_vsock.h       |   9 +
 net/vmw_vsock/af_vsock.c                | 483 ++++++++++++++++------
 net/vmw_vsock/virtio_transport.c        |   4 +
 net/vmw_vsock/virtio_transport_common.c | 294 +++++++++++--
 tools/testing/vsock/util.c              |  32 +-
 tools/testing/vsock/util.h              |   3 +
 tools/testing/vsock/vsock_test.c        | 126 ++++++
 10 files changed, 824 insertions(+), 152 deletions(-)

 v1 -> v2:
 - patches reordered: af_vsock.c changes now before virtio vsock
 - patches reorganized: more small patches, where +/- are not mixed
 - tests for SOCK_SEQPACKET added
 - all commit messages updated
 - af_vsock.c: 'vsock_pre_recv_check()' inlined to
   'vsock_connectible_recvmsg()'
 - af_vsock.c: 'vsock_assign_transport()' returns ENODEV if transport
   was not found
 - virtio_transport_common.c: transport callback for seqpacket dequeue
 - virtio_transport_common.c: simplified
   'virtio_transport_recv_connected()'
 - virtio_transport_common.c: send reset on socket and packet type
			      mismatch.

Signed-off-by: Arseny Krasnov <arseny.krasnov@xxxxxxxxxxxxx>

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2.25.1