On Tue, Jul 07, 2015 at 04:58:29PM +0800, Jason Wang wrote:
>
>
> On 07/07/2015 04:13 PM, Michael S. Tsirkin wrote:
> > On Tue, Jul 07, 2015 at 09:21:07AM +0800, 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>
> > Note virtio has its own handler which must be used to
> > flush packets - this one might run too early or too late.
>
> If runs too realy (DRIVER_OK is not set), then: packet will be dropped
> (if this patch is used with "drop virtio_net_can_receive()", or the
> queue will be purged since qemu_can_send_packet() returns false. If too
> late, at least tap read poll will be enabled. So still looks ok?
It's still not helpful for virtio. So which cards are fixed?
I just find the comment
This fixes the case of "cont" after "stop" (or migration)
too vague.
Can you please include the info about what's broken in the commit log?
> >
> >> ---
> >>
> >> 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);
> >> }
> >> }
> >> --
> >> 2.4.3
