Re: [Qemu-devel] [PATCH for-2.4 v2] xen: Drop net_rx_ok

[Fam Zheng <famz@redhat.com>]

On Tue, 07/28 17:32, Wen Congyang wrote:
> On 07/28/2015 05:25 PM, Fam Zheng wrote:
> > Let net_rx_packet() (which checks the same conditions) drops the packet
> > if the device is not ready. Drop net_xen_info.can_receive and update the
> > return value for the buffer full case.
> > 
> > We rely on the qemu_flush_queued_packets() in net_event() to wake up
> > the peer when the buffer becomes available again.
> > 
> > Signed-off-by: Fam Zheng <famz@redhat.com>
> > 
> > ---
> > 
> > v2:
> >     Fix return value of net_rx_packet to keep the semantics when ring
> >     buffer is full. [Stefan]
> >     Update commit message accordingly.
> > ---
> >  hw/net/xen_nic.c | 24 +-----------------------
> >  1 file changed, 1 insertion(+), 23 deletions(-)
> > 
> > diff --git a/hw/net/xen_nic.c b/hw/net/xen_nic.c
> > index 19ecfc4..acb7e2e 100644
> > --- a/hw/net/xen_nic.c
> > +++ b/hw/net/xen_nic.c
> > @@ -234,27 +234,6 @@ static void net_rx_response(struct XenNetDev *netdev,
> >  
> >  #define NET_IP_ALIGN 2
> >  
> > -static int net_rx_ok(NetClientState *nc)
> > -{
> > -    struct XenNetDev *netdev = qemu_get_nic_opaque(nc);
> > -    RING_IDX rc, rp;
> > -
> > -    if (netdev->xendev.be_state != XenbusStateConnected) {
> > -        return 0;
> > -    }
> > -
> > -    rc = netdev->rx_ring.req_cons;
> > -    rp = netdev->rx_ring.sring->req_prod;
> > -    xen_rmb();
> > -
> > -    if (rc == rp || RING_REQUEST_CONS_OVERFLOW(&netdev->rx_ring, rc)) {
> > -        xen_be_printf(&netdev->xendev, 2, "%s: no rx buffers (%d/%d)\n",
> > -                      __FUNCTION__, rc, rp);
> > -        return 0;
> > -    }
> > -    return 1;
> > -}
> > -
> >  static ssize_t net_rx_packet(NetClientState *nc, const uint8_t *buf, size_t size)
> >  {
> >      struct XenNetDev *netdev = qemu_get_nic_opaque(nc);
> > @@ -272,7 +251,7 @@ static ssize_t net_rx_packet(NetClientState *nc, const uint8_t *buf, size_t size
> >  
> >      if (rc == rp || RING_REQUEST_CONS_OVERFLOW(&netdev->rx_ring, rc)) {
> >          xen_be_printf(&netdev->xendev, 2, "no buffer, drop packet\n");
> 
> IIUC, 'return 0' means that the packet will be queued in the incoming queue. So the log should
> be changed too.

You're right, will fix.

Fam