Avoid the situation where the frontend is sending packets but the
domain 0 bridging (or whatever) is not yet configured (because the
hotplug scripts are too slow) and so packets get dropped.
Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
Cc: Steven.Smith@xxxxxxxxxx
---
drivers/xen/netback/common.h | 2 +
drivers/xen/netback/xenbus.c | 45 +++++++++++++++++++++++++++++++++++++++++-
2 files changed, 46 insertions(+), 1 deletions(-)
diff --git a/drivers/xen/netback/common.h b/drivers/xen/netback/common.h
index ea617b9..51f97c0 100644
--- a/drivers/xen/netback/common.h
+++ b/drivers/xen/netback/common.h
@@ -147,6 +147,8 @@ struct backend_info {
struct xenbus_device *dev;
struct xen_netif *netif;
enum xenbus_state frontend_state;
+ struct xenbus_watch hotplug_status_watch;
+ int have_hotplug_status_watch:1;
/* State relating to the netback accelerator */
void *netback_accel_priv;
diff --git a/drivers/xen/netback/xenbus.c b/drivers/xen/netback/xenbus.c
index b114aa4..b89853a 100644
--- a/drivers/xen/netback/xenbus.c
+++ b/drivers/xen/netback/xenbus.c
@@ -32,6 +32,7 @@
static int connect_rings(struct backend_info *);
static void connect(struct backend_info *);
static void backend_create_netif(struct backend_info *be);
+static void unregister_hotplug_status_watch(struct backend_info *be);
static int netback_remove(struct xenbus_device *dev)
{
@@ -39,8 +40,10 @@ static int netback_remove(struct xenbus_device *dev)
//netback_remove_accelerators(be, dev);
+ unregister_hotplug_status_watch(be);
if (be->netif) {
kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE);
+ xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status");
netif_disconnect(be->netif);
be->netif = NULL;
}
@@ -218,6 +221,7 @@ static void disconnect_backend(struct xenbus_device *dev)
struct backend_info *be = dev_get_drvdata(&dev->dev);
if (be->netif) {
+ xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status");
netif_disconnect(be->netif);
be->netif = NULL;
}
@@ -337,6 +341,36 @@ static int xen_net_read_mac(struct xenbus_device *dev, u8
mac[])
return 0;
}
+static void unregister_hotplug_status_watch(struct backend_info *be)
+{
+ if (be->have_hotplug_status_watch) {
+ unregister_xenbus_watch(&be->hotplug_status_watch);
+ kfree(be->hotplug_status_watch.node);
+ }
+ be->have_hotplug_status_watch = 0;
+}
+
+static void hotplug_status_changed(struct xenbus_watch *watch,
+ const char **vec,
+ unsigned int vec_size)
+{
+ struct backend_info *be = container_of(watch,
+ struct backend_info,
+ hotplug_status_watch);
+ char *str;
+ unsigned int len;
+
+ str = xenbus_read(XBT_NIL, be->dev->nodename, "hotplug-status", &len);
+ if (IS_ERR(str))
+ return;
+ if (len == sizeof("connected")-1 && !memcmp(str, "connected", len)) {
+ xenbus_switch_state(be->dev, XenbusStateConnected);
+ /* Not interested in this watch anymore. */
+ unregister_hotplug_status_watch(be);
+ }
+ kfree(str);
+}
+
static void connect(struct backend_info *be)
{
int err;
@@ -356,7 +390,16 @@ static void connect(struct backend_info *be)
&be->netif->credit_usec);
be->netif->remaining_credit = be->netif->credit_bytes;
- xenbus_switch_state(dev, XenbusStateConnected);
+ unregister_hotplug_status_watch(be);
+ err = xenbus_watch_pathfmt(dev, &be->hotplug_status_watch,
+ hotplug_status_changed,
+ "%s/%s", dev->nodename, "hotplug-status");
+ if (err) {
+ /* Switch now, since we can't do a watch. */
+ xenbus_switch_state(dev, XenbusStateConnected);
+ } else {
+ be->have_hotplug_status_watch = 1;
+ }
netif_wake_queue(be->netif->dev);
}
--
1.5.6.5
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