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authorLuigi Rizzo <rizzo@iet.unipi.it>2013-02-05 17:53:31 +0100
committerStefan Hajnoczi <stefanha@redhat.com>2013-02-27 16:10:23 +0100
commit199ee608f0d08510b5c6c37f31a7fbff211d63c4 (patch)
tree62d264bb698419fdc701bd11830d47d905cab9e8 /net
parentee24aaf356f44ca7c8fbef136a438c12091cffd0 (diff)
net: fix qemu_flush_queued_packets() in presence of a hub
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. Signed-off-by: Luigi Rizzo <rizzo@iet.unipi.it> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'net')
-rw-r--r--net/hub.c14
-rw-r--r--net/hub.h1
-rw-r--r--net/net.c6
3 files changed, 21 insertions, 0 deletions
diff --git a/net/hub.c b/net/hub.c
index a24c9d17f7..df32074de0 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 583ada89d8..a625effe00 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 be03a8dd14..a66aa02472 100644
--- a/net/net.c
+++ b/net/net.c
@@ -441,6 +441,12 @@ 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).