[PATCH] [6/106] staging: hv: Fix GARP not sent after Quick Migration

[Andi Kleen]

2.6.35-longterm review patch.  If anyone has any objections, please let me know.

------------------
From: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>

commit c996edcf1c451b81740abbcca5257ed7e353fcc6 upstream.

After Quick Migration, the network is not immediately operational in the
current context when receiving RNDIS_STATUS_MEDIA_CONNECT event. So, I added
another netif_notify_peers() into a scheduled work, otherwise GARP packet will
not be sent after quick migration, and cause network disconnection.

Thanks to Mike Surcouf <mike@xxxxxxxxxxxxx> for reporting the bug and
testing the patch.

Reported-by: Mike Surcouf <mike@xxxxxxxxxxxxx>
Tested-by: Mike Surcouf <mike@xxxxxxxxxxxxx>
Signed-off-by: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
Signed-off-by: Hank Janssen <hjanssen@xxxxxxxxxxxxx>
Signed-off-by: Abhishek Kane <v-abkane@xxxxxxxxxxxxx>
Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>

---
 drivers/staging/hv/netvsc_drv.c |   24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

Index: linux-2.6.35.y/drivers/staging/hv/netvsc_drv.c
===================================================================
--- linux-2.6.35.y.orig/drivers/staging/hv/netvsc_drv.c
+++ linux-2.6.35.y/drivers/staging/hv/netvsc_drv.c
@@ -46,6 +46,7 @@ struct net_device_context {
 	/* point back to our device context */
 	struct vm_device *device_ctx;
 	unsigned long avail;
+	struct work_struct work;
 };
 
 struct netvsc_driver_context {
@@ -237,6 +238,7 @@ static void netvsc_linkstatus_callback(s
 {
 	struct vm_device *device_ctx = to_vm_device(device_obj);
 	struct net_device *net = dev_get_drvdata(&device_ctx->device);
+	struct net_device_context *ndev_ctx;
 
 	DPRINT_ENTER(NETVSC_DRV);
 
@@ -250,6 +252,8 @@ static void netvsc_linkstatus_callback(s
 		netif_carrier_on(net);
 		netif_wake_queue(net);
 		netif_notify_peers(net);
+		ndev_ctx = netdev_priv(net);
+		schedule_work(&ndev_ctx->work);
 	} else {
 		netif_carrier_off(net);
 		netif_stop_queue(net);
@@ -354,6 +358,25 @@ static const struct net_device_ops devic
 	.ndo_set_mac_address =		eth_mac_addr,
 };
 
+/*
+ * Send GARP packet to network peers after migrations.
+ * After Quick Migration, the network is not immediately operational in the
+ * current context when receiving RNDIS_STATUS_MEDIA_CONNECT event. So, add
+ * another netif_notify_peers() into a scheduled work, otherwise GARP packet
+ * will not be sent after quick migration, and cause network disconnection.
+ */
+static void netvsc_send_garp(struct work_struct *w)
+{
+	struct net_device_context *ndev_ctx;
+	struct net_device *net;
+
+	msleep(20);
+	ndev_ctx = container_of(w, struct net_device_context, work);
+	net = dev_get_drvdata(&ndev_ctx->device_ctx->device);
+	netif_notify_peers(net);
+}
+
+
 static int netvsc_probe(struct device *device)
 {
 	struct driver_context *driver_ctx =
@@ -385,6 +408,7 @@ static int netvsc_probe(struct device *d
 	net_device_ctx->device_ctx = device_ctx;
 	net_device_ctx->avail = ring_size;
 	dev_set_drvdata(device, net);
+	INIT_WORK(&net_device_ctx->work, netvsc_send_garp);
 
 	/* Notify the netvsc driver of the new device */
 	ret = net_drv_obj->Base.OnDeviceAdd(device_obj, &device_info);
--
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