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  • * Re: [PATCH net-next v5 0/6] virtio/vsock: introduce MSG_EOR flag for SEQPACKET
           [not found] <20210903123016.3272800-1-arseny.krasnov@kaspersky.com>
           [not found] ` <20210903123238.3273526-1-arseny.krasnov@kaspersky.com>
    @ 2021-09-05 15:55 ` Michael S. Tsirkin
           [not found]   ` <4558e96b-6330-667f-955b-b689986f884f@kaspersky.com>
      1 sibling, 1 reply; 6+ messages in thread
    From: Michael S. Tsirkin @ 2021-09-05 15:55 UTC (permalink / raw)
      To: Arseny Krasnov
      Cc: Andra Paraschiv, kvm, netdev, stsp2, linux-kernel, virtualization,
    	oxffffaa, Norbert Slusarek, Stefan Hajnoczi, Jakub Kicinski,
    	Colin Ian King, David S. Miller
    
    On Fri, Sep 03, 2021 at 03:30:13PM +0300, Arseny Krasnov wrote:
    > 	This patchset implements support of MSG_EOR bit for SEQPACKET
    > AF_VSOCK sockets over virtio transport.
    > 	First we need to define 'messages' and 'records' like this:
    > Message is result of sending calls: 'write()', 'send()', 'sendmsg()'
    > etc. It has fixed maximum length, and it bounds are visible using
    > return from receive calls: 'read()', 'recv()', 'recvmsg()' etc.
    > Current implementation based on message definition above.
    > 	Record has unlimited length, it consists of multiple message,
    > and bounds of record are visible via MSG_EOR flag returned from
    > 'recvmsg()' call. Sender passes MSG_EOR to sending system call and
    > receiver will see MSG_EOR when corresponding message will be processed.
    > 	Idea of patchset comes from POSIX: it says that SEQPACKET
    > supports record boundaries which are visible for receiver using
    > MSG_EOR bit. So, it looks like MSG_EOR is enough thing for SEQPACKET
    > and we don't need to maintain boundaries of corresponding send -
    > receive system calls. But, for 'sendXXX()' and 'recXXX()' POSIX says,
    > that all these calls operates with messages, e.g. 'sendXXX()' sends
    > message, while 'recXXX()' reads messages and for SEQPACKET, 'recXXX()'
    > must read one entire message from socket, dropping all out of size
    > bytes. Thus, both message boundaries and MSG_EOR bit must be supported
    > to follow POSIX rules.
    > 	To support MSG_EOR new bit was added along with existing
    > 'VIRTIO_VSOCK_SEQ_EOR': 'VIRTIO_VSOCK_SEQ_EOM'(end-of-message) - now it
    > works in the same way as 'VIRTIO_VSOCK_SEQ_EOR'. But 'VIRTIO_VSOCK_SEQ_EOR'
    > is used to mark 'MSG_EOR' bit passed from userspace.
    > 	This patchset includes simple test for MSG_EOR.
    
    
    I'm prepared to merge this for this window,
    but I'm not sure who's supposed to ack the net/vmw_vsock/af_vsock.c
    bits. It's a harmless variable renaming so maybe it does not matter.
    
    The rest is virtio stuff so I guess my tree is ok.
    
    Objections, anyone?
    
    
    
    >  Arseny Krasnov(6):
    >   virtio/vsock: rename 'EOR' to 'EOM' bit.
    >   virtio/vsock: add 'VIRTIO_VSOCK_SEQ_EOR' bit.
    >   vhost/vsock: support MSG_EOR bit processing
    >   virtio/vsock: support MSG_EOR bit processing
    >   af_vsock: rename variables in receive loop
    >   vsock_test: update message bounds test for MSG_EOR
    > 
    >  drivers/vhost/vsock.c                   | 28 +++++++++++++----------
    >  include/uapi/linux/virtio_vsock.h       |  3 ++-
    >  net/vmw_vsock/af_vsock.c                | 10 ++++----
    >  net/vmw_vsock/virtio_transport_common.c | 23 ++++++++++++-------
    >  tools/testing/vsock/vsock_test.c        |  8 ++++++-
    >  5 files changed, 45 insertions(+), 27 deletions(-)
    > 
    >  v4 -> v5:
    >  - Move bitwise and out of le32_to_cpu() in 0003.
    > 
    >  v3 -> v4:
    >  - 'sendXXX()' renamed to 'send*()' in 0002- commit msg.
    >  - Comment about bit restore updated in 0003-.
    >  - 'same' renamed to 'similar' in 0003- commit msg.
    >  - u32 used instead of uint32_t in 0003-.
    > 
    >  v2 -> v3:
    >  - 'virtio/vsock: rename 'EOR' to 'EOM' bit.' - commit message updated.
    >  - 'VIRTIO_VSOCK_SEQ_EOR' bit add moved to separate patch.
    >  - 'vhost/vsock: support MSG_EOR bit processing' - commit message
    >    updated.
    >  - 'vhost/vsock: support MSG_EOR bit processing' - removed unneeded
    >    'le32_to_cpu()', because input argument was already in CPU
    >    endianness.
    > 
    >  v1 -> v2:
    >  - 'VIRTIO_VSOCK_SEQ_EOR' is renamed to 'VIRTIO_VSOCK_SEQ_EOM', to
    >    support backward compatibility.
    >  - use bitmask of flags to restore in vhost.c, instead of separated
    >    bool variable for each flag.
    >  - test for EAGAIN removed, as logically it is not part of this
    >    patchset(will be sent separately).
    >  - cover letter updated(added part with POSIX description).
    > 
    > Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
    > -- 
    > 2.25.1
    
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    ^ permalink raw reply	[flat|nested] 6+ messages in thread

  • end of thread, other threads:[~2021-09-06  8:03 UTC | newest]
    
    Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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         [not found] <20210903123016.3272800-1-arseny.krasnov@kaspersky.com>
         [not found] ` <20210903123238.3273526-1-arseny.krasnov@kaspersky.com>
    2021-09-03 12:51   ` [PATCH net-next v5 3/6] vhost/vsock: support MSG_EOR bit processing Stefano Garzarella
    2021-09-05 15:55 ` [PATCH net-next v5 0/6] virtio/vsock: introduce MSG_EOR flag for SEQPACKET Michael S. Tsirkin
         [not found]   ` <4558e96b-6330-667f-955b-b689986f884f@kaspersky.com>
    2021-09-05 16:19     ` Michael S. Tsirkin
         [not found]       ` <5b20410a-fb8f-2e38-59d9-74dc6b8a9d4f@kaspersky.com>
    2021-09-05 20:18         ` Michael S. Tsirkin
    2021-09-06  7:33           ` Stefano Garzarella
    2021-09-06  8:03             ` Michael S. Tsirkin
    

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