On Tue, Jun 30, 2015 at 6:47 PM, Fam Zheng <f...@redhat.com> wrote:
> On Tue, 06/30 07:41, sfel...@gmail.com wrote:
>> From: Scott Feldman <sfel...@gmail.com>
>>
>> Commit 6e99c63 ("net/socket: Drop net_socket_can_send") changed the
>> semantics around .can_receive for sockets to now require the device to
>> flush queued pkts when transitioning to a .can_receive=true state. Rocker
>> device was not flushing the queue on .can_receive=true transition, so the
>> receiver was stuck.
>>
>> But, turns out we really don't want any queuing at all on the port when the
>> port is disabled, otherwise when the port transitions to enabled, we'd
>> receive and forward stale pkts that really should have been dropped. So,
>> let's remove .can_receive so avoid queuing and drop the pkt in .receive if
>> the port is disabled.
>>
>> Signed-off-by: Scott Feldman <sfel...@gmail.com>
>> ---
>> hw/net/rocker/rocker_fp.c | 18 ++++++++++--------
>> 1 file changed, 10 insertions(+), 8 deletions(-)
>>
>> diff --git a/hw/net/rocker/rocker_fp.c b/hw/net/rocker/rocker_fp.c
>> index d8d934c..ac53c13 100644
>> --- a/hw/net/rocker/rocker_fp.c
>> +++ b/hw/net/rocker/rocker_fp.c
>> @@ -125,18 +125,21 @@ int fp_port_eg(FpPort *port, const struct iovec *iov,
>> int iovcnt)
>> return ROCKER_OK;
>> }
>>
>> -static int fp_port_can_receive(NetClientState *nc)
>> -{
>> - FpPort *port = qemu_get_nic_opaque(nc);
>> -
>> - return port->enabled;
>> -}
>> -
>> static ssize_t fp_port_receive_iov(NetClientState *nc, const struct iovec
>> *iov,
>> int iovcnt)
>> {
>> FpPort *port = qemu_get_nic_opaque(nc);
>>
>> + /* If the port is disabled, we want to drop this pkt
>> + * now rather than queing it for later. We don't want
>> + * any stale pkts getting into the device when the port
>> + * transitions to enabled.
>> + */
>> +
>> + if (!port->enabled) {
>> + return iov_size(iov, iovcnt);
>
> Other devices return -1 when dropping packets, for example see
> e1000_receive_iov or virtio_net_receive. Maybe return -1 here too?
I posted v2 with the change. Perhaps we should have:
#define QEMU_SEND_PACKET_DROPPED -1
Or something like that...
-scott
