| Message ID | 20130205165331.GA31226@onelab2.iet.unipi.it |
|---|---|
| State | New |
| Headers | show |
On Tue, Feb 05, 2013 at 05:53:31PM +0100, Luigi Rizzo wrote: > DESCRIPTION: > > When frontend and backend are connected through a hub as below > (showing only one direction), and the frontend (or in general, all > output ports of the hub) cannot accept more traffic, the backend > queues packets in queue-A. > > When the frontend (or in general, one output port) becomes ready again, > quemu tries to flush packets from queue-B, which is unfortunately empty. > > e1000.0 <--[queue B]-- hub0port0(hub)hub0port1 <--[queue A]-- tap.0 > > To fix this i propose to introduce a new function net_hub_flush() > which is called when trying to flush a queue connected to a hub. > > cheers > luigi > > Signed-off-by: Luigi Rizzo <rizzo@iet.unipi.it> Thanks, applied to the net-next tree: https://github.com/stefanha/qemu/commits/net-next This patch will be part of the first net pull request for QEMU 1.5. Stefan
diff --git a/net/hub.c b/net/hub.c index a24c9d1..df32074 100644 --- a/net/hub.c +++ b/net/hub.c @@ -338,3 +338,17 @@ void net_hub_check_clients(void) } } } + +bool net_hub_flush(NetClientState *nc) +{ + NetHubPort *port; + NetHubPort *source_port = DO_UPCAST(NetHubPort, nc, nc); + int ret = 0; + + QLIST_FOREACH(port, &source_port->hub->ports, next) { + if (port != source_port) { + ret += qemu_net_queue_flush(port->nc.send_queue); + } + } + return ret ? true : false; +} diff --git a/net/hub.h b/net/hub.h index 583ada8..a625eff 100644 --- a/net/hub.h +++ b/net/hub.h @@ -21,5 +21,6 @@ NetClientState *net_hub_add_port(int hub_id, const char *name); NetClientState *net_hub_find_client_by_name(int hub_id, const char *name); void net_hub_info(Monitor *mon); void net_hub_check_clients(void); +bool net_hub_flush(NetClientState *nc); #endif /* NET_HUB_H */ diff --git a/net/net.c b/net/net.c index 9806862..9489702 100644 --- a/net/net.c +++ b/net/net.c @@ -439,6 +439,12 @@ void qemu_flush_queued_packets(NetClientState *nc) { nc->receive_disabled = 0; + if (nc->peer && nc->peer->info->type == NET_CLIENT_OPTIONS_KIND_HUBPORT) { + if (net_hub_flush(nc->peer)) { + qemu_notify_event(); + } + return; + } if (qemu_net_queue_flush(nc->send_queue)) { /* We emptied the queue successfully, signal to the IO thread to repoll * the file descriptor (for tap, for example).
DESCRIPTION: When frontend and backend are connected through a hub as below (showing only one direction), and the frontend (or in general, all output ports of the hub) cannot accept more traffic, the backend queues packets in queue-A. When the frontend (or in general, one output port) becomes ready again, quemu tries to flush packets from queue-B, which is unfortunately empty. e1000.0 <--[queue B]-- hub0port0(hub)hub0port1 <--[queue A]-- tap.0 To fix this i propose to introduce a new function net_hub_flush() which is called when trying to flush a queue connected to a hub. cheers luigi Signed-off-by: Luigi Rizzo <rizzo@iet.unipi.it>