From b103f358d9f6f58658f1a6dc08912ab921dd86f1 Mon Sep 17 00:00:00 2001 From: Wei Liu Date: Thu, 16 May 2013 23:26:11 +0000 Subject: [PATCH] xen-netback: enable user to unload netback module MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 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/common.h | 1 + drivers/net/xen-netback/interface.c | 19 ++++++++++++++++++- drivers/net/xen-netback/netback.c | 20 ++++++++++++++++++++ drivers/net/xen-netback/xenbus.c | 5 +++++ 4 files changed, 44 insertions(+), 1 deletion(-) diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h index 9d7f172..6102a6c 100644 --- a/drivers/net/xen-netback/common.h +++ b/drivers/net/xen-netback/common.h @@ -120,6 +120,7 @@ void xenvif_get(struct xenvif *vif); void xenvif_put(struct xenvif *vif); int xenvif_xenbus_init(void); +void xenvif_xenbus_fini(void); int xenvif_schedulable(struct xenvif *vif); 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 @@ 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); } diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index 295a9c2..2d9477f 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -1949,5 +1949,25 @@ failed_init: module_init(netback_init); +static void __exit netback_fini(void) +{ + int i, j; + + xenvif_xenbus_fini(); + + for (i = 0; i < xen_netbk_group_nr; i++) { + struct xen_netbk *netbk = &xen_netbk[i]; + del_timer_sync(&netbk->net_timer); + kthread_stop(netbk->task); + for (j = 0; j < MAX_PENDING_REQS; j++) { + if (netbk->mmap_pages[i]) + __free_page(netbk->mmap_pages[i]); + } + } + + vfree(xen_netbk); +} +module_exit(netback_fini); + MODULE_LICENSE("Dual BSD/GPL"); MODULE_ALIAS("xen-backend:vif"); diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c index 410018c..d230c14 100644 --- a/drivers/net/xen-netback/xenbus.c +++ b/drivers/net/xen-netback/xenbus.c @@ -485,3 +485,8 @@ int xenvif_xenbus_init(void) { return xenbus_register_backend(&netback_driver); } + +void xenvif_xenbus_fini(void) +{ + return xenbus_unregister_driver(&netback_driver); +} -- 2.7.4