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Commit b103f358 authored by Wei Liu's avatar Wei Liu Committed by David S. Miller
Browse files

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: default avatarWei Liu <wei.liu2@citrix.com>
Acked-by: default avatarIan Campbell <ian.campbell@citrix.com&gt;¬>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f1db320e

drivers/net/xen-netback/common.h

+1 −0
Original line number Diff line number Diff line
@@ -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);

drivers/net/xen-netback/interface.c

+18 −1
Original line number Diff line number Diff line
@@ -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);

}

drivers/net/xen-netback/netback.c

+20 −0
Original line number Diff line number Diff line
@@ -1949,5 +1949,25 @@ static int __init netback_init(void) 


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");

drivers/net/xen-netback/xenbus.c

+5 −0
Original line number Diff line number Diff line
@@ -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);

}