[PATCH net-next] xen-netback: enable user to unload netback module
DORMANTno replies
From: Wei Liu <hidden>
Date: 2013-05-17 09:26:22
Subsystem:
networking drivers, the rest, xen network backend driver · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Wei Liu, Paul Durrant
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 <redacted> Acked-by: Ian Campbell <redacted>¬ --- 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); +}
--
1.7.10.4