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xen-netback: enable user to unload netback module

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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 <wei.liu2@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>¬
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Wei Liu
2013-05-16 23:26:11 +00:00
committed by David S. Miller
parent f1db320ec5
commit b103f358d9
4 changed files with 44 additions and 1 deletions
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19
drivers/net/xen-netback/interface.c
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@@ -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);
}