Re: [PATCH v11 00/18] virtio/vsock: introduce SOCK_SEQPACKET support

Arseny Krasnov
2021-06-11T11:17:18Z

On 11.06.2021 14:07, Arseny Krasnov wrote:
> This patchset implements support of SOCK_SEQPACKET for virtio
> transport.
> As SOCK_SEQPACKET guarantees to save record boundaries, so to
> do it, new bit for field 'flags' was added: SEQ_EOR. This bit is
> set to 1 in last RW packet of message.
> Now as packets of one socket are not reordered neither on vsock
> nor on vhost transport layers, such bit allows to restore original
> message on receiver's side. If user's buffer is smaller than message
> length, when all out of size data is dropped.
> Maximum length of datagram is limited by 'peer_buf_alloc' value.
> Implementation also supports 'MSG_TRUNC' flags.
> Tests also implemented.
>
> Thanks to stsp2@yandex.ru for encouragements and initial design
> recommendations.
>
> Arseny Krasnov (18):
> af_vsock: update functions for connectible socket
> af_vsock: separate wait data loop
> af_vsock: separate receive data loop
> af_vsock: implement SEQPACKET receive loop
> af_vsock: implement send logic for SEQPACKET
> af_vsock: rest of SEQPACKET support
> af_vsock: update comments for stream sockets
> virtio/vsock: set packet's type in virtio_transport_send_pkt_info()
> virtio/vsock: simplify credit update function API
> virtio/vsock: defines and constants for SEQPACKET
> virtio/vsock: dequeue callback for SOCK_SEQPACKET
> virtio/vsock: add SEQPACKET receive logic
> virtio/vsock: rest of SOCK_SEQPACKET support
> virtio/vsock: enable SEQPACKET for transport
> vhost/vsock: enable SEQPACKET for transport
> vsock/loopback: enable SEQPACKET for transport
> vsock_test: add SOCK_SEQPACKET tests
> virtio/vsock: update trace event for SEQPACKET
>
> drivers/vhost/vsock.c | 56 ++-
> include/linux/virtio_vsock.h | 10 +
> include/net/af_vsock.h | 8 +
> .../trace/events/vsock_virtio_transport_common.h | 5 +-
> include/uapi/linux/virtio_vsock.h | 9 +
> net/vmw_vsock/af_vsock.c | 464 ++++++++++++------
> net/vmw_vsock/virtio_transport.c | 26 ++
> net/vmw_vsock/virtio_transport_common.c | 179 +++++++-
> net/vmw_vsock/vsock_loopback.c | 12 +
> tools/testing/vsock/util.c | 32 +-
> tools/testing/vsock/util.h | 3 +
> tools/testing/vsock/vsock_test.c | 116 ++++++
> 12 files changed, 730 insertions(+), 190 deletions(-)
>
> v10 -> v11:
> General changelog:
> - now data is copied to user's buffer only when
> whole message is received.
> - reader is woken up when EOR packet is received.
> - if read syscall was interrupted by signal or
> timeout, error is returned(not 0).
>
> Per patch changelog:
> see every patch after '---' line.
So here is new version for review with updates discussed earlier :)
>
> v9 -> v10:
> General changelog:
> - patch for write serialization removed from patchset.
> - commit messages rephrased
>
> Per patch changelog:
> see every patch after '---' line.
>
> v8 -> v9:
> General changelog:
> - see per patch change log.
>
> Per patch changelog:
> see every patch after '---' line.
>
> v7 -> v8:
> General changelog:
> - whole idea is simplified: channel now considered reliable,
> so SEQ_BEGIN, SEQ_END, 'msg_len' and 'msg_id' were removed.
> Only thing that is used to mark end of message is bit in
> 'flags' field of packet header: VIRTIO_VSOCK_SEQ_EOR. Packet
> with such bit set to 1 means, that this is last packet of
> message.
>
> - POSIX MSG_EOR support is removed, as there is no exact
> description how it works.
>
> - all changes to 'include/uapi/linux/virtio_vsock.h' moved
> to dedicated patch, as these changes linked with patch to
> spec.
>
> - patch 'virtio/vsock: SEQPACKET feature bit support' now merged
> to 'virtio/vsock: setup SEQPACKET ops for transport'.
>
> - patch 'vhost/vsock: SEQPACKET feature bit support' now merged
> to 'vhost/vsock: setup SEQPACKET ops for transport'.
>
> Per patch changelog:
> see every patch after '---' line.
>
> v6 -> v7:
> General changelog:
> - virtio transport callback for message length now removed
> from transport. Length of record is returned by dequeue
> callback.
>
> - function which tries to get message length now returns 0
> when rx queue is empty. Also length of current message in
> progress is set to 0, when message processed or error
> happens.
>
> - patches for virtio feature bit moved after patches with
> transport ops.
>
> Per patch changelog:
> see every patch after '---' line.
>
> v5 -> v6:
> General changelog:
> - virtio transport specific callbacks which send SEQ_BEGIN or
> SEQ_END now hidden inside virtio transport. Only enqueue,
> dequeue and record length callbacks are provided by transport.
>
> - virtio feature bit for SEQPACKET socket support introduced:
> VIRTIO_VSOCK_F_SEQPACKET.
>
> - 'msg_cnt' field in 'struct virtio_vsock_seq_hdr' renamed to
> 'msg_id' and used as id.
>
> Per patch changelog:
> - 'af_vsock: separate wait data loop':
> 1) Commit message updated.
> 2) 'prepare_to_wait()' moved inside while loop(thanks to
> Jorgen Hansen).
> Marked 'Reviewed-by' with 1), but as 2) I removed R-b.
>
> - 'af_vsock: separate receive data loop': commit message
> updated.
> Marked 'Reviewed-by' with that fix.
>
> - 'af_vsock: implement SEQPACKET receive loop': style fixes.
>
> - 'af_vsock: rest of SEQPACKET support':
> 1) 'module_put()' added when transport callback check failed.
> 2) Now only 'seqpacket_allow()' callback called to check
> support of SEQPACKET by transport.
>
> - 'af_vsock: update comments for stream sockets': commit message
> updated.
> Marked 'Reviewed-by' with that fix.
>
> - 'virtio/vsock: set packet's type in send':
> 1) Commit message updated.
> 2) Parameter 'type' from 'virtio_transport_send_credit_update()'
> also removed in this patch instead of in next.
>
> - 'virtio/vsock: dequeue callback for SOCK_SEQPACKET': SEQPACKET
> related state wrapped to special struct.
>
> - 'virtio/vsock: update trace event for SEQPACKET': format strings
> now not broken by new lines.
>
> v4 -> v5:
> - patches reorganized:
> 1) Setting of packet's type in 'virtio_transport_send_pkt_info()'
> is moved to separate patch.
> 2) Simplifying of 'virtio_transport_send_credit_update()' is
> moved to separate patch and before main virtio/vsock patches.
> - style problem fixed
> - in 'af_vsock: separate receive data loop' extra 'release_sock()'
> removed
> - added trace event fields for SEQPACKET
> - in 'af_vsock: separate wait data loop':
> 1) 'vsock_wait_data()' removed 'goto out;'
> 2) Comment for invalid data amount is changed.
> - in 'af_vsock: rest of SEQPACKET support', 'new_transport' pointer
> check is moved after 'try_module_get()'
> - in 'af_vsock: update comments for stream sockets', 'connect-oriented'
> replaced with 'connection-oriented'
> - in 'loopback/vsock: setup SEQPACKET ops for transport',
> 'loopback/vsock' replaced with 'vsock/loopback'
>
> v3 -> v4:
> - SEQPACKET specific metadata moved from packet header to payload
> and called 'virtio_vsock_seq_hdr'
> - record integrity check:
> 1) SEQ_END operation was added, which marks end of record.
> 2) Both SEQ_BEGIN and SEQ_END carries counter which is incremented
> on every marker send.
> - af_vsock.c: socket operations for STREAM and SEQPACKET call same
> functions instead of having own "gates" differs only by names:
> 'vsock_seqpacket/stream_getsockopt()' now replaced with
> 'vsock_connectible_getsockopt()'.
> - af_vsock.c: 'seqpacket_dequeue' callback returns error and flag that
> record ready. There is no need to return number of copied bytes,
> because case when record received successfully is checked at virtio
> transport layer, when SEQ_END is processed. Also user doesn't need
> number of copied bytes, because 'recv()' from SEQPACKET could return
> error, length of users's buffer or length of whole record(both are
> known in af_vsock.c).
> - af_vsock.c: both wait loops in af_vsock.c(for data and space) moved
> to separate functions because now both called from several places.
> - af_vsock.c: 'vsock_assign_transport()' checks that 'new_transport'
> pointer is not NULL and returns 'ESOCKTNOSUPPORT' instead of 'ENODEV'
> if failed to use transport.
> - tools/testing/vsock/vsock_test.c: rename tests
>
> v2 -> v3:
> - patches reorganized: split for prepare and implementation patches
> - local variables are declared in "Reverse Christmas tree" manner
> - virtio_transport_common.c: valid leXX_to_cpu() for vsock header
> fields access
> - af_vsock.c: 'vsock_connectible_*sockopt()' added as shared code
> between stream and seqpacket sockets.
> - af_vsock.c: loops in '__vsock_*_recvmsg()' refactored.
> - af_vsock.c: 'vsock_wait_data()' refactored.
>
> v1 -> v2:
> - patches reordered: af_vsock.c related 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@kaspersky.com>
>