xen-netback: enable user to unload netback module
This patch enables user to unload netback module, which is useful when user
wants to upgrade to a newer netback module without rebooting the host.
Netfront cannot handle netback removal event. As we cannot fix all possible
frontends we add module get / put along with vif get / put to avoid
mis-unloading of netback. To unload netback module, user needs to shutdown all
VMs or migrate them to another host or unplug all vifs before hand.
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>¬
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index d984141..82202c2 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -316,6 +316,8 @@
if (vif->irq)
return 0;
+ __module_get(THIS_MODULE);
+
err = xen_netbk_map_frontend_rings(vif, tx_ring_ref, rx_ring_ref);
if (err < 0)
goto err;
@@ -343,6 +345,7 @@
err_unmap:
xen_netbk_unmap_frontend_rings(vif);
err:
+ module_put(THIS_MODULE);
return err;
}
@@ -360,18 +363,32 @@
void xenvif_disconnect(struct xenvif *vif)
{
+ /* Disconnect funtion might get called by generic framework
+ * even before vif connects, so we need to check if we really
+ * need to do a module_put.
+ */
+ int need_module_put = 0;
+
if (netif_carrier_ok(vif->dev))
xenvif_carrier_off(vif);
atomic_dec(&vif->refcnt);
wait_event(vif->waiting_to_free, atomic_read(&vif->refcnt) == 0);
- if (vif->irq)
+ if (vif->irq) {
unbind_from_irqhandler(vif->irq, vif);
+ /* vif->irq is valid, we had a module_get in
+ * xenvif_connect.
+ */
+ need_module_put = 1;
+ }
unregister_netdev(vif->dev);
xen_netbk_unmap_frontend_rings(vif);
free_netdev(vif->dev);
+
+ if (need_module_put)
+ module_put(THIS_MODULE);
}