Re: [RFC PATCH v1 3/7] vhost/vsock: support MSG_EOR bit processing

[Stefano Garzarella]

On Fri, Aug 06, 2021 at 11:40:38AM +0300, Arseny Krasnov wrote:
> On 06.08.2021 10:28, Stefano Garzarella wrote:
> > Caution: This is an external email. Be cautious while opening links or attachments.
> >
> >
> >
> > On Mon, Jul 26, 2021 at 07:33:38PM +0300, Arseny Krasnov wrote:
> > > It works in the same way as 'end-of-message' bit: if packet has
> > > 'EOM' bit, also check for 'EOR' bit.
> > >
> > > Signed-off-by: Arseny Krasnov <arseny.krasnov@xxxxxxxxxxxxx>
> > > ---
> > > drivers/vhost/vsock.c | 12 +++++++++++-
> > > 1 file changed, 11 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
> > > index 3b55de70ac77..3e2b150f9c6f 100644
> > > --- a/drivers/vhost/vsock.c
> > > +++ b/drivers/vhost/vsock.c
> > > @@ -115,6 +115,7 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
> > >               size_t iov_len, payload_len;
> > >               int head;
> > >               bool restore_msg_eom_flag = false;
> > > +              bool restore_msg_eor_flag = false;
> > Since we now have 2 flags to potentially restore, we could use a single
> > variable (e.g. uint32_t flags_to_restore), initialized to 0.
> >
> > We can set all the flags we need to restore and then simply put it
> > in or with the `pkt->hdr.flags` field.
> >
> > >               spin_lock_bh(&vsock->send_pkt_list_lock);
> > >               if (list_empty(&vsock->send_pkt_list)) {
> > > @@ -188,6 +189,11 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
> > >                       if (le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SEQ_EOM) {
> > >                               pkt->hdr.flags &= ~cpu_to_le32(VIRTIO_VSOCK_SEQ_EOM);
> > >                               restore_msg_eom_flag = true;
> > > +
> > > +                              if (le32_to_cpu(pkt->hdr.flags & VIRTIO_VSOCK_SEQ_EOR)) {
> >                                                                 ^
> > Here it should be `le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SEQ_EOR`
> >
> > > +                                      pkt->hdr.flags &= ~cpu_to_le32(VIRTIO_VSOCK_SEQ_EOR);
> > > +                                      restore_msg_eor_flag = true;
> > > +                              }
> > >                       }
> > >               }
> > >
> > > @@ -224,9 +230,13 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
> > >                * to send it with the next available buffer.
> > >                */
> > >               if (pkt->off < pkt->len) {
> > > -                      if (restore_msg_eom_flag)
> > > +                      if (restore_msg_eom_flag) {
> > >                               pkt->hdr.flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOM);
> > >
> > > +                              if (restore_msg_eor_flag)
> > > +                                      pkt->hdr.flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOR);
> > > +                      }
> > > +
> > If we use a single variable, here we can simply do:
> >
> >                         pkt->hdr.flags |= cpu_to_le32(flags_to_restore);
> >
> > Stefano
>
> Thanks, i'll prepare v2 both with spec patch. About spec: i've already sent
>
> patch for SEQPACKET, can i prepare spec patch updating current reviewed
>
> SEQPACKET? E.g. i'll include both EOM and EOR in one patch.

Yep, since spec is not yet merged, I think make sense to have all 
seqpacket stuff in a single patch.

Thanks,
Stefano