On 15.03.2021 14:40, Stefano Garzarella wrote:
> Hi Arseny,
>
> On Sun, Mar 07, 2021 at 08:57:19PM +0300, 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, two new packet operations were added: first for start of record
>> and second to mark end of record(SEQ_BEGIN and SEQ_END later). Also,
>> both operations carries metadata - to maintain boundaries and payload
>> integrity. Metadata is introduced by adding special header with two
>> fields - message id and message length:
>>
>> struct virtio_vsock_seq_hdr {
>> __le32 msg_id;
>> __le32 msg_len;
>> } __attribute__((packed));
>>
>> This header is transmitted as payload of SEQ_BEGIN and SEQ_END
>> packets(buffer of second virtio descriptor in chain) in the same way as
>> data transmitted in RW packets. Payload was chosen as buffer for this
>> header to avoid touching first virtio buffer which carries header of
>> packet, because someone could check that size of this buffer is equal
>> to size of packet header. To send record, packet with start marker is
>> sent first(it's header carries length of record and id),then all data
>> is sent as usual 'RW' packets and finally SEQ_END is sent(it carries
>> id of message, which is equal to id of SEQ_BEGIN), also after sending
>> SEQ_END id is incremented. On receiver's side,size of record is known
> >from packet with start record marker. To check that no packets were
>> dropped by transport, 'msg_id's of two sequential SEQ_BEGIN and SEQ_END
>> are checked to be equal and length of data between two markers is
>> compared to then length in SEQ_BEGIN header.
>> Now as packets of one socket are not reordered neither on
>> vsock nor on vhost transport layers, such markers 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.
>>
>> Thanks to stsp2@xxxxxxxxx for encouragements and initial design
>> recommendations.
>>
>> Arseny Krasnov (22):
>> 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: separate wait space 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: dequeue callback for SOCK_SEQPACKET
>> virtio/vsock: fetch length for SEQPACKET record
>> virtio/vsock: add SEQPACKET receive logic
>> virtio/vsock: rest of SOCK_SEQPACKET support
>> virtio/vsock: SEQPACKET feature bit
>> vhost/vsock: SEQPACKET feature bit support
>> virtio/vsock: SEQPACKET feature bit support
>> virtio/vsock: setup SEQPACKET ops for transport
>> vhost/vsock: setup SEQPACKET ops for transport
>> vsock/loopback: setup SEQPACKET ops for transport
>> vsock_test: add SOCK_SEQPACKET tests
>> virtio/vsock: update trace event for SEQPACKET
>>
>> drivers/vhost/vsock.c | 22 +-
>> include/linux/virtio_vsock.h | 22 +
>> include/net/af_vsock.h | 10 +
>> .../events/vsock_virtio_transport_common.h | 48 +-
>> include/uapi/linux/virtio_vsock.h | 19 +
>> net/vmw_vsock/af_vsock.c | 589 +++++++++++------
>> net/vmw_vsock/virtio_transport.c | 18 +
>> net/vmw_vsock/virtio_transport_common.c | 364 ++++++++--
>> net/vmw_vsock/vsock_loopback.c | 13 +
>> tools/testing/vsock/util.c | 32 +-
>> tools/testing/vsock/util.h | 3 +
>> tools/testing/vsock/vsock_test.c | 126 ++++
>> 12 files changed, 1013 insertions(+), 253 deletions(-)
>>
>> 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.
> I left a bunch of comments in the patches, I hope they are easy to fix
> :-)
Thank you, yes, there are still small fixes.
>
> Thanks for the changelogs. About 'per patch changelog', it is very
> useful!
> Just a suggestion, I think is better to include them in each patch after
> the '---' to simplify the review.
Ack
>
> You can use git-notes(1) or you can simply edit the format-patch and add
> the changelog after the 3 dashes, so that they are ignored when the
> patch is applied.
>
> Thanks,
> Stefano
>
>
