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Date: Mon, 6 May 2013 17:11:46 +0100
From: Wei Liu <wei.liu2@...rix.com>
To: <netdev@...r.kernel.org>, <xen-devel@...ts.xen.org>
CC: <ian.campbell@...rix.com>, Wei Liu <wei.liu2@...rix.com>
Subject: [PATCH net-next] 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 before hand.
Signed-off-by: Wei Liu <wei.liu2@...rix.com>
---
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
--
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