From b103f358d9f6f58658f1a6dc08912ab921dd86f1 Mon Sep 17 00:00:00 2001 From: Wei Liu Date: Thu, 16 May 2013 23:26:11 +0000 Subject: xen-netback: enable user to unload netback module MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Acked-by: Ian Campbell ¬ Signed-off-by: David S. Miller --- drivers/net/xen-netback/interface.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) (limited to 'drivers/net/xen-netback/interface.c') diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c index d98414168485..82202c2b1bd1 100644 --- a/drivers/net/xen-netback/interface.c +++ b/drivers/net/xen-netback/interface.c @@ -316,6 +316,8 @@ int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref, 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 @@ int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref, err_unmap: xen_netbk_unmap_frontend_rings(vif); err: + module_put(THIS_MODULE); return err; } @@ -360,18 +363,32 @@ void xenvif_carrier_off(struct xenvif *vif) 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); } -- cgit v1.2.3