On 07/07/2015 09:21 AM, Fam Zheng wrote:
> Since commit 6e99c63 "net/socket: Drop net_socket_can_send" and friends,
> net queues need to be explicitly flushed after qemu_can_send_packet()
> returns false, because the netdev side will disable the polling of fd.
>
> This fixes the case of "cont" after "stop" (or migration).
>
> Signed-off-by: Fam Zheng <f...@redhat.com>
>
> ---
>
> v2: Unify with VM stop handler. (Stefan)
> ---
> net/net.c | 19 ++++++++++++-------
> 1 file changed, 12 insertions(+), 7 deletions(-)
>
> diff --git a/net/net.c b/net/net.c
> index 6ff7fec..28a5597 100644
> --- a/net/net.c
> +++ b/net/net.c
> @@ -1257,14 +1257,19 @@ void qmp_set_link(const char *name, bool up, Error
> **errp)
> static void net_vm_change_state_handler(void *opaque, int running,
> RunState state)
> {
> - /* Complete all queued packets, to guarantee we don't modify
> - * state later when VM is not running.
> - */
> - if (!running) {
> - NetClientState *nc;
> - NetClientState *tmp;
> + NetClientState *nc;
> + NetClientState *tmp;
>
> - QTAILQ_FOREACH_SAFE(nc, &net_clients, next, tmp) {
> + QTAILQ_FOREACH_SAFE(nc, &net_clients, next, tmp) {
> + if (running) {
> + /* Flush queued packets and wake up backends. */
> + if (nc->peer && qemu_can_send_packet(nc)) {
> + qemu_flush_queued_packets(nc->peer);
> + }
> + } else {
> + /* Complete all queued packets, to guarantee we don't modify
> + * state later when VM is not running.
> + */
> qemu_flush_or_purge_queued_packets(nc, true);
> }
Looks like qemu_can_send_packet() checks both nc->peer and runstate. So
probably, we can simplify this to:
if (qemu_can_send_packet(nc))
qemu_flush_queued_packets(nc->peer);
else
qemu_flush_or_purge_queued_packets(nc, true);
> }
